diff options
Diffstat (limited to '')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 12089 |
1 files changed, 7495 insertions, 4594 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 313034117070..efab29b8935b 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -31,11 +31,10 @@ #include <linux/bpf.h> #include <linux/btf.h> #include <linux/filter.h> -#include <linux/list.h> #include <linux/limits.h> #include <linux/perf_event.h> +#include <linux/bpf_perf_event.h> #include <linux/ring_buffer.h> -#include <linux/version.h> #include <sys/epoll.h> #include <sys/ioctl.h> #include <sys/mman.h> @@ -54,15 +53,15 @@ #include "str_error.h" #include "libbpf_internal.h" #include "hashmap.h" - -#ifndef EM_BPF -#define EM_BPF 247 -#endif +#include "bpf_gen_internal.h" +#include "zip.h" #ifndef BPF_FS_MAGIC #define BPF_FS_MAGIC 0xcafe4a11 #endif +#define BPF_FS_DEFAULT_PATH "/sys/fs/bpf" + #define BPF_INSN_SZ (sizeof(struct bpf_insn)) /* vsprintf() in __base_pr() uses nonliteral format string. It may break @@ -73,8 +72,157 @@ #define __printf(a, b) __attribute__((format(printf, a, b))) static struct bpf_map *bpf_object__add_map(struct bpf_object *obj); -static const struct btf_type * -skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); +static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog); +static int map_set_def_max_entries(struct bpf_map *map); + +static const char * const attach_type_name[] = { + [BPF_CGROUP_INET_INGRESS] = "cgroup_inet_ingress", + [BPF_CGROUP_INET_EGRESS] = "cgroup_inet_egress", + [BPF_CGROUP_INET_SOCK_CREATE] = "cgroup_inet_sock_create", + [BPF_CGROUP_INET_SOCK_RELEASE] = "cgroup_inet_sock_release", + [BPF_CGROUP_SOCK_OPS] = "cgroup_sock_ops", + [BPF_CGROUP_DEVICE] = "cgroup_device", + [BPF_CGROUP_INET4_BIND] = "cgroup_inet4_bind", + [BPF_CGROUP_INET6_BIND] = "cgroup_inet6_bind", + [BPF_CGROUP_INET4_CONNECT] = "cgroup_inet4_connect", + [BPF_CGROUP_INET6_CONNECT] = "cgroup_inet6_connect", + [BPF_CGROUP_UNIX_CONNECT] = "cgroup_unix_connect", + [BPF_CGROUP_INET4_POST_BIND] = "cgroup_inet4_post_bind", + [BPF_CGROUP_INET6_POST_BIND] = "cgroup_inet6_post_bind", + [BPF_CGROUP_INET4_GETPEERNAME] = "cgroup_inet4_getpeername", + [BPF_CGROUP_INET6_GETPEERNAME] = "cgroup_inet6_getpeername", + [BPF_CGROUP_UNIX_GETPEERNAME] = "cgroup_unix_getpeername", + [BPF_CGROUP_INET4_GETSOCKNAME] = "cgroup_inet4_getsockname", + [BPF_CGROUP_INET6_GETSOCKNAME] = "cgroup_inet6_getsockname", + [BPF_CGROUP_UNIX_GETSOCKNAME] = "cgroup_unix_getsockname", + [BPF_CGROUP_UDP4_SENDMSG] = "cgroup_udp4_sendmsg", + [BPF_CGROUP_UDP6_SENDMSG] = "cgroup_udp6_sendmsg", + [BPF_CGROUP_UNIX_SENDMSG] = "cgroup_unix_sendmsg", + [BPF_CGROUP_SYSCTL] = "cgroup_sysctl", + [BPF_CGROUP_UDP4_RECVMSG] = "cgroup_udp4_recvmsg", + [BPF_CGROUP_UDP6_RECVMSG] = "cgroup_udp6_recvmsg", + [BPF_CGROUP_UNIX_RECVMSG] = "cgroup_unix_recvmsg", + [BPF_CGROUP_GETSOCKOPT] = "cgroup_getsockopt", + [BPF_CGROUP_SETSOCKOPT] = "cgroup_setsockopt", + [BPF_SK_SKB_STREAM_PARSER] = "sk_skb_stream_parser", + [BPF_SK_SKB_STREAM_VERDICT] = "sk_skb_stream_verdict", + [BPF_SK_SKB_VERDICT] = "sk_skb_verdict", + [BPF_SK_MSG_VERDICT] = "sk_msg_verdict", + [BPF_LIRC_MODE2] = "lirc_mode2", + [BPF_FLOW_DISSECTOR] = "flow_dissector", + [BPF_TRACE_RAW_TP] = "trace_raw_tp", + [BPF_TRACE_FENTRY] = "trace_fentry", + [BPF_TRACE_FEXIT] = "trace_fexit", + [BPF_MODIFY_RETURN] = "modify_return", + [BPF_LSM_MAC] = "lsm_mac", + [BPF_LSM_CGROUP] = "lsm_cgroup", + [BPF_SK_LOOKUP] = "sk_lookup", + [BPF_TRACE_ITER] = "trace_iter", + [BPF_XDP_DEVMAP] = "xdp_devmap", + [BPF_XDP_CPUMAP] = "xdp_cpumap", + [BPF_XDP] = "xdp", + [BPF_SK_REUSEPORT_SELECT] = "sk_reuseport_select", + [BPF_SK_REUSEPORT_SELECT_OR_MIGRATE] = "sk_reuseport_select_or_migrate", + [BPF_PERF_EVENT] = "perf_event", + [BPF_TRACE_KPROBE_MULTI] = "trace_kprobe_multi", + [BPF_STRUCT_OPS] = "struct_ops", + [BPF_NETFILTER] = "netfilter", + [BPF_TCX_INGRESS] = "tcx_ingress", + [BPF_TCX_EGRESS] = "tcx_egress", + [BPF_TRACE_UPROBE_MULTI] = "trace_uprobe_multi", + [BPF_NETKIT_PRIMARY] = "netkit_primary", + [BPF_NETKIT_PEER] = "netkit_peer", +}; + +static const char * const link_type_name[] = { + [BPF_LINK_TYPE_UNSPEC] = "unspec", + [BPF_LINK_TYPE_RAW_TRACEPOINT] = "raw_tracepoint", + [BPF_LINK_TYPE_TRACING] = "tracing", + [BPF_LINK_TYPE_CGROUP] = "cgroup", + [BPF_LINK_TYPE_ITER] = "iter", + [BPF_LINK_TYPE_NETNS] = "netns", + [BPF_LINK_TYPE_XDP] = "xdp", + [BPF_LINK_TYPE_PERF_EVENT] = "perf_event", + [BPF_LINK_TYPE_KPROBE_MULTI] = "kprobe_multi", + [BPF_LINK_TYPE_STRUCT_OPS] = "struct_ops", + [BPF_LINK_TYPE_NETFILTER] = "netfilter", + [BPF_LINK_TYPE_TCX] = "tcx", + [BPF_LINK_TYPE_UPROBE_MULTI] = "uprobe_multi", + [BPF_LINK_TYPE_NETKIT] = "netkit", +}; + +static const char * const map_type_name[] = { + [BPF_MAP_TYPE_UNSPEC] = "unspec", + [BPF_MAP_TYPE_HASH] = "hash", + [BPF_MAP_TYPE_ARRAY] = "array", + [BPF_MAP_TYPE_PROG_ARRAY] = "prog_array", + [BPF_MAP_TYPE_PERF_EVENT_ARRAY] = "perf_event_array", + [BPF_MAP_TYPE_PERCPU_HASH] = "percpu_hash", + [BPF_MAP_TYPE_PERCPU_ARRAY] = "percpu_array", + [BPF_MAP_TYPE_STACK_TRACE] = "stack_trace", + [BPF_MAP_TYPE_CGROUP_ARRAY] = "cgroup_array", + [BPF_MAP_TYPE_LRU_HASH] = "lru_hash", + [BPF_MAP_TYPE_LRU_PERCPU_HASH] = "lru_percpu_hash", + [BPF_MAP_TYPE_LPM_TRIE] = "lpm_trie", + [BPF_MAP_TYPE_ARRAY_OF_MAPS] = "array_of_maps", + [BPF_MAP_TYPE_HASH_OF_MAPS] = "hash_of_maps", + [BPF_MAP_TYPE_DEVMAP] = "devmap", + [BPF_MAP_TYPE_DEVMAP_HASH] = "devmap_hash", + [BPF_MAP_TYPE_SOCKMAP] = "sockmap", + [BPF_MAP_TYPE_CPUMAP] = "cpumap", + [BPF_MAP_TYPE_XSKMAP] = "xskmap", + [BPF_MAP_TYPE_SOCKHASH] = "sockhash", + [BPF_MAP_TYPE_CGROUP_STORAGE] = "cgroup_storage", + [BPF_MAP_TYPE_REUSEPORT_SOCKARRAY] = "reuseport_sockarray", + [BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE] = "percpu_cgroup_storage", + [BPF_MAP_TYPE_QUEUE] = "queue", + [BPF_MAP_TYPE_STACK] = "stack", + [BPF_MAP_TYPE_SK_STORAGE] = "sk_storage", + [BPF_MAP_TYPE_STRUCT_OPS] = "struct_ops", + [BPF_MAP_TYPE_RINGBUF] = "ringbuf", + [BPF_MAP_TYPE_INODE_STORAGE] = "inode_storage", + [BPF_MAP_TYPE_TASK_STORAGE] = "task_storage", + [BPF_MAP_TYPE_BLOOM_FILTER] = "bloom_filter", + [BPF_MAP_TYPE_USER_RINGBUF] = "user_ringbuf", + [BPF_MAP_TYPE_CGRP_STORAGE] = "cgrp_storage", + [BPF_MAP_TYPE_ARENA] = "arena", +}; + +static const char * const prog_type_name[] = { + [BPF_PROG_TYPE_UNSPEC] = "unspec", + [BPF_PROG_TYPE_SOCKET_FILTER] = "socket_filter", + [BPF_PROG_TYPE_KPROBE] = "kprobe", + [BPF_PROG_TYPE_SCHED_CLS] = "sched_cls", + [BPF_PROG_TYPE_SCHED_ACT] = "sched_act", + [BPF_PROG_TYPE_TRACEPOINT] = "tracepoint", + [BPF_PROG_TYPE_XDP] = "xdp", + [BPF_PROG_TYPE_PERF_EVENT] = "perf_event", + [BPF_PROG_TYPE_CGROUP_SKB] = "cgroup_skb", + [BPF_PROG_TYPE_CGROUP_SOCK] = "cgroup_sock", + [BPF_PROG_TYPE_LWT_IN] = "lwt_in", + [BPF_PROG_TYPE_LWT_OUT] = "lwt_out", + [BPF_PROG_TYPE_LWT_XMIT] = "lwt_xmit", + [BPF_PROG_TYPE_SOCK_OPS] = "sock_ops", + [BPF_PROG_TYPE_SK_SKB] = "sk_skb", + [BPF_PROG_TYPE_CGROUP_DEVICE] = "cgroup_device", + [BPF_PROG_TYPE_SK_MSG] = "sk_msg", + [BPF_PROG_TYPE_RAW_TRACEPOINT] = "raw_tracepoint", + [BPF_PROG_TYPE_CGROUP_SOCK_ADDR] = "cgroup_sock_addr", + [BPF_PROG_TYPE_LWT_SEG6LOCAL] = "lwt_seg6local", + [BPF_PROG_TYPE_LIRC_MODE2] = "lirc_mode2", + [BPF_PROG_TYPE_SK_REUSEPORT] = "sk_reuseport", + [BPF_PROG_TYPE_FLOW_DISSECTOR] = "flow_dissector", + [BPF_PROG_TYPE_CGROUP_SYSCTL] = "cgroup_sysctl", + [BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE] = "raw_tracepoint_writable", + [BPF_PROG_TYPE_CGROUP_SOCKOPT] = "cgroup_sockopt", + [BPF_PROG_TYPE_TRACING] = "tracing", + [BPF_PROG_TYPE_STRUCT_OPS] = "struct_ops", + [BPF_PROG_TYPE_EXT] = "ext", + [BPF_PROG_TYPE_LSM] = "lsm", + [BPF_PROG_TYPE_SK_LOOKUP] = "sk_lookup", + [BPF_PROG_TYPE_SYSCALL] = "syscall", + [BPF_PROG_TYPE_NETFILTER] = "netfilter", +}; static int __base_pr(enum libbpf_print_level level, const char *format, va_list args) @@ -89,9 +237,10 @@ static libbpf_print_fn_t __libbpf_pr = __base_pr; libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn) { - libbpf_print_fn_t old_print_fn = __libbpf_pr; + libbpf_print_fn_t old_print_fn; + + old_print_fn = __atomic_exchange_n(&__libbpf_pr, fn, __ATOMIC_RELAXED); - __libbpf_pr = fn; return old_print_fn; } @@ -99,13 +248,20 @@ __printf(2, 3) void libbpf_print(enum libbpf_print_level level, const char *format, ...) { va_list args; + int old_errno; + libbpf_print_fn_t print_fn; - if (!__libbpf_pr) + print_fn = __atomic_load_n(&__libbpf_pr, __ATOMIC_RELAXED); + if (!print_fn) return; + old_errno = errno; + va_start(args, format); __libbpf_pr(level, format, args); va_end(args); + + errno = old_errno; } static void pr_perm_msg(int err) @@ -155,62 +311,89 @@ static inline __u64 ptr_to_u64(const void *ptr) return (__u64) (unsigned long) ptr; } -enum kern_feature_id { - /* v4.14: kernel support for program & map names. */ - FEAT_PROG_NAME, - /* v5.2: kernel support for global data sections. */ - FEAT_GLOBAL_DATA, - /* BTF support */ - FEAT_BTF, - /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */ - FEAT_BTF_FUNC, - /* BTF_KIND_VAR and BTF_KIND_DATASEC support */ - FEAT_BTF_DATASEC, - /* BTF_FUNC_GLOBAL is supported */ - FEAT_BTF_GLOBAL_FUNC, - /* BPF_F_MMAPABLE is supported for arrays */ - FEAT_ARRAY_MMAP, - /* kernel support for expected_attach_type in BPF_PROG_LOAD */ - FEAT_EXP_ATTACH_TYPE, - /* bpf_probe_read_{kernel,user}[_str] helpers */ - FEAT_PROBE_READ_KERN, - /* BPF_PROG_BIND_MAP is supported */ - FEAT_PROG_BIND_MAP, - __FEAT_CNT, -}; +int libbpf_set_strict_mode(enum libbpf_strict_mode mode) +{ + /* as of v1.0 libbpf_set_strict_mode() is a no-op */ + return 0; +} + +__u32 libbpf_major_version(void) +{ + return LIBBPF_MAJOR_VERSION; +} + +__u32 libbpf_minor_version(void) +{ + return LIBBPF_MINOR_VERSION; +} -static bool kernel_supports(enum kern_feature_id feat_id); +const char *libbpf_version_string(void) +{ +#define __S(X) #X +#define _S(X) __S(X) + return "v" _S(LIBBPF_MAJOR_VERSION) "." _S(LIBBPF_MINOR_VERSION); +#undef _S +#undef __S +} enum reloc_type { RELO_LD64, RELO_CALL, RELO_DATA, - RELO_EXTERN, + RELO_EXTERN_LD64, + RELO_EXTERN_CALL, + RELO_SUBPROG_ADDR, + RELO_CORE, }; struct reloc_desc { enum reloc_type type; int insn_idx; - int map_idx; - int sym_off; - bool processed; + union { + const struct bpf_core_relo *core_relo; /* used when type == RELO_CORE */ + struct { + int map_idx; + int sym_off; + int ext_idx; + }; + }; }; -struct bpf_sec_def; - -typedef struct bpf_link *(*attach_fn_t)(const struct bpf_sec_def *sec, - struct bpf_program *prog); +/* stored as sec_def->cookie for all libbpf-supported SEC()s */ +enum sec_def_flags { + SEC_NONE = 0, + /* expected_attach_type is optional, if kernel doesn't support that */ + SEC_EXP_ATTACH_OPT = 1, + /* legacy, only used by libbpf_get_type_names() and + * libbpf_attach_type_by_name(), not used by libbpf itself at all. + * This used to be associated with cgroup (and few other) BPF programs + * that were attachable through BPF_PROG_ATTACH command. Pretty + * meaningless nowadays, though. + */ + SEC_ATTACHABLE = 2, + SEC_ATTACHABLE_OPT = SEC_ATTACHABLE | SEC_EXP_ATTACH_OPT, + /* attachment target is specified through BTF ID in either kernel or + * other BPF program's BTF object + */ + SEC_ATTACH_BTF = 4, + /* BPF program type allows sleeping/blocking in kernel */ + SEC_SLEEPABLE = 8, + /* BPF program support non-linear XDP buffer */ + SEC_XDP_FRAGS = 16, + /* Setup proper attach type for usdt probes. */ + SEC_USDT = 32, +}; struct bpf_sec_def { - const char *sec; - size_t len; + char *sec; enum bpf_prog_type prog_type; enum bpf_attach_type expected_attach_type; - bool is_exp_attach_type_optional; - bool is_attachable; - bool is_attach_btf; - bool is_sleepable; - attach_fn_t attach_fn; + long cookie; + int handler_id; + + libbpf_prog_setup_fn_t prog_setup_fn; + libbpf_prog_prepare_load_fn_t prog_prepare_load_fn; + libbpf_prog_attach_fn_t prog_attach_fn; }; /* @@ -218,9 +401,10 @@ struct bpf_sec_def { * linux/filter.h. */ struct bpf_program { - const struct bpf_sec_def *sec_def; + char *name; char *sec_name; size_t sec_idx; + const struct bpf_sec_def *sec_def; /* this program's instruction offset (in number of instructions) * within its containing ELF section */ @@ -240,12 +424,6 @@ struct bpf_program { */ size_t sub_insn_off; - char *name; - /* sec_name with / replaced by _; makes recursive pinning - * in bpf_object__pin_programs easier - */ - char *pin_name; - /* instructions that belong to BPF program; insns[0] is located at * sec_insn_off instruction within its ELF section in ELF file, so * when mapping ELF file instruction index to the local instruction, @@ -260,24 +438,28 @@ struct bpf_program { struct reloc_desc *reloc_desc; int nr_reloc; - int log_level; - struct { - int nr; - int *fds; - } instances; - bpf_program_prep_t preprocessor; + /* BPF verifier log settings */ + char *log_buf; + size_t log_size; + __u32 log_level; struct bpf_object *obj; - void *priv; - bpf_program_clear_priv_t clear_priv; - bool load; + int fd; + bool autoload; + bool autoattach; + bool sym_global; + bool mark_btf_static; enum bpf_prog_type type; enum bpf_attach_type expected_attach_type; + int exception_cb_idx; + int prog_ifindex; + __u32 attach_btf_obj_fd; __u32 attach_btf_id; __u32 attach_prog_fd; + void *func_info; __u32 func_info_rec_size; __u32 func_info_cnt; @@ -315,6 +497,8 @@ struct bpf_struct_ops { #define KCONFIG_SEC ".kconfig" #define KSYMS_SEC ".ksyms" #define STRUCT_OPS_SEC ".struct_ops" +#define STRUCT_OPS_LINK_SEC ".struct_ops.link" +#define ARENA_SEC ".arena.1" enum libbpf_map_type { LIBBPF_MAP_UNSPEC, @@ -324,15 +508,23 @@ enum libbpf_map_type { LIBBPF_MAP_KCONFIG, }; -static const char * const libbpf_type_to_btf_name[] = { - [LIBBPF_MAP_DATA] = DATA_SEC, - [LIBBPF_MAP_BSS] = BSS_SEC, - [LIBBPF_MAP_RODATA] = RODATA_SEC, - [LIBBPF_MAP_KCONFIG] = KCONFIG_SEC, +struct bpf_map_def { + unsigned int type; + unsigned int key_size; + unsigned int value_size; + unsigned int max_entries; + unsigned int map_flags; }; struct bpf_map { + struct bpf_object *obj; char *name; + /* real_name is defined for special internal maps (.rodata*, + * .data*, .bss, .kconfig) and preserves their original ELF section + * name. This is important to be able to find corresponding BTF + * DATASEC information. + */ + char *real_name; int fd; int sec_idx; size_t sec_offset; @@ -341,11 +533,10 @@ struct bpf_map { struct bpf_map_def def; __u32 numa_node; __u32 btf_var_idx; + int mod_btf_fd; __u32 btf_key_type_id; __u32 btf_value_type_id; __u32 btf_vmlinux_value_type_id; - void *priv; - bpf_map_clear_priv_t clear_priv; enum libbpf_map_type libbpf_type; void *mmaped; struct bpf_struct_ops *st_ops; @@ -355,6 +546,8 @@ struct bpf_map { char *pin_path; bool pinned; bool reused; + bool autocreate; + __u64 map_extra; }; enum extern_type { @@ -378,6 +571,7 @@ struct extern_desc { int btf_id; int sec_btf_id; const char *name; + char *essent_name; bool is_set; bool is_weak; union { @@ -392,15 +586,64 @@ struct extern_desc { unsigned long long addr; /* target btf_id of the corresponding kernel var. */ - int vmlinux_btf_id; + int kernel_btf_obj_fd; + int kernel_btf_id; /* local btf_id of the ksym extern's type. */ __u32 type_id; + /* BTF fd index to be patched in for insn->off, this is + * 0 for vmlinux BTF, index in obj->fd_array for module + * BTF + */ + __s16 btf_fd_idx; } ksym; }; }; -static LIST_HEAD(bpf_objects_list); +struct module_btf { + struct btf *btf; + char *name; + __u32 id; + int fd; + int fd_array_idx; +}; + +enum sec_type { + SEC_UNUSED = 0, + SEC_RELO, + SEC_BSS, + SEC_DATA, + SEC_RODATA, + SEC_ST_OPS, +}; + +struct elf_sec_desc { + enum sec_type sec_type; + Elf64_Shdr *shdr; + Elf_Data *data; +}; + +struct elf_state { + int fd; + const void *obj_buf; + size_t obj_buf_sz; + Elf *elf; + Elf64_Ehdr *ehdr; + Elf_Data *symbols; + Elf_Data *arena_data; + size_t shstrndx; /* section index for section name strings */ + size_t strtabidx; + struct elf_sec_desc *secs; + size_t sec_cnt; + int btf_maps_shndx; + __u32 btf_maps_sec_btf_id; + int text_shndx; + int symbols_shndx; + bool has_st_ops; + int arena_data_shndx; +}; + +struct usdt_manager; struct bpf_object { char name[BPF_OBJ_NAME_LEN]; @@ -417,95 +660,73 @@ struct bpf_object { struct extern_desc *externs; int nr_extern; int kconfig_map_idx; - int rodata_map_idx; bool loaded; bool has_subcalls; + bool has_rodata; - /* - * Information when doing elf related work. Only valid if fd - * is valid. - */ - struct { - int fd; - const void *obj_buf; - size_t obj_buf_sz; - Elf *elf; - GElf_Ehdr ehdr; - Elf_Data *symbols; - Elf_Data *data; - Elf_Data *rodata; - Elf_Data *bss; - Elf_Data *st_ops_data; - size_t shstrndx; /* section index for section name strings */ - size_t strtabidx; - struct { - GElf_Shdr shdr; - Elf_Data *data; - } *reloc_sects; - int nr_reloc_sects; - int maps_shndx; - int btf_maps_shndx; - __u32 btf_maps_sec_btf_id; - int text_shndx; - int symbols_shndx; - int data_shndx; - int rodata_shndx; - int bss_shndx; - int st_ops_shndx; - } efile; - /* - * All loaded bpf_object is linked in a list, which is - * hidden to caller. bpf_objects__<func> handlers deal with - * all objects. - */ - struct list_head list; + struct bpf_gen *gen_loader; + + /* Information when doing ELF related work. Only valid if efile.elf is not NULL */ + struct elf_state efile; struct btf *btf; + struct btf_ext *btf_ext; + /* Parse and load BTF vmlinux if any of the programs in the object need * it at load time. */ struct btf *btf_vmlinux; - struct btf_ext *btf_ext; - - void *priv; - bpf_object_clear_priv_t clear_priv; + /* Path to the custom BTF to be used for BPF CO-RE relocations as an + * override for vmlinux BTF. + */ + char *btf_custom_path; + /* vmlinux BTF override for CO-RE relocations */ + struct btf *btf_vmlinux_override; + /* Lazily initialized kernel module BTFs */ + struct module_btf *btf_modules; + bool btf_modules_loaded; + size_t btf_module_cnt; + size_t btf_module_cap; + + /* optional log settings passed to BPF_BTF_LOAD and BPF_PROG_LOAD commands */ + char *log_buf; + size_t log_size; + __u32 log_level; + + int *fd_array; + size_t fd_array_cap; + size_t fd_array_cnt; + + struct usdt_manager *usdt_man; + + struct bpf_map *arena_map; + void *arena_data; + size_t arena_data_sz; + + struct kern_feature_cache *feat_cache; + char *token_path; + int token_fd; char path[]; }; -#define obj_elf_valid(o) ((o)->efile.elf) static const char *elf_sym_str(const struct bpf_object *obj, size_t off); static const char *elf_sec_str(const struct bpf_object *obj, size_t off); static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx); static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name); -static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr); +static Elf64_Shdr *elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn); static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn); static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn); -static int elf_sym_by_sec_off(const struct bpf_object *obj, size_t sec_idx, - size_t off, __u32 sym_type, GElf_Sym *sym); +static Elf64_Sym *elf_sym_by_idx(const struct bpf_object *obj, size_t idx); +static Elf64_Rel *elf_rel_by_idx(Elf_Data *data, size_t idx); void bpf_program__unload(struct bpf_program *prog) { - int i; - if (!prog) return; - /* - * If the object is opened but the program was never loaded, - * it is possible that prog->instances.nr == -1. - */ - if (prog->instances.nr > 0) { - for (i = 0; i < prog->instances.nr; i++) - zclose(prog->instances.fds[i]); - } else if (prog->instances.nr != -1) { - pr_warn("Internal error: instances.nr is %d\n", - prog->instances.nr); - } - - prog->instances.nr = -1; - zfree(&prog->instances.fds); + zclose(prog->fd); zfree(&prog->func_info); zfree(&prog->line_info); @@ -516,16 +737,9 @@ static void bpf_program__exit(struct bpf_program *prog) if (!prog) return; - if (prog->clear_priv) - prog->clear_priv(prog, prog->priv); - - prog->priv = NULL; - prog->clear_priv = NULL; - bpf_program__unload(prog); zfree(&prog->name); zfree(&prog->sec_name); - zfree(&prog->pin_name); zfree(&prog->insns); zfree(&prog->reloc_desc); @@ -534,17 +748,6 @@ static void bpf_program__exit(struct bpf_program *prog) prog->sec_idx = -1; } -static char *__bpf_program__pin_name(struct bpf_program *prog) -{ - char *name, *p; - - name = p = strdup(prog->sec_name); - while ((p = strchr(p, '/'))) - *p = '_'; - - return name; -} - static bool insn_is_subprog_call(const struct bpf_insn *insn) { return BPF_CLASS(insn->code) == BPF_JMP && @@ -555,13 +758,21 @@ static bool insn_is_subprog_call(const struct bpf_insn *insn) insn->off == 0; } +static bool is_call_insn(const struct bpf_insn *insn) +{ + return insn->code == (BPF_JMP | BPF_CALL); +} + +static bool insn_is_pseudo_func(struct bpf_insn *insn) +{ + return is_ldimm64_insn(insn) && insn->src_reg == BPF_PSEUDO_FUNC; +} + static int bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog, const char *name, size_t sec_idx, const char *sec_name, size_t sec_off, void *insn_data, size_t insn_data_sz) { - int i; - if (insn_data_sz == 0 || insn_data_sz % BPF_INSN_SZ || sec_off % BPF_INSN_SZ) { pr_warn("sec '%s': corrupted program '%s', offset %zu, size %zu\n", sec_name, name, sec_off, insn_data_sz); @@ -578,10 +789,25 @@ bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog, prog->insns_cnt = prog->sec_insn_cnt; prog->type = BPF_PROG_TYPE_UNSPEC; - prog->load = true; + prog->fd = -1; + prog->exception_cb_idx = -1; + + /* libbpf's convention for SEC("?abc...") is that it's just like + * SEC("abc...") but the corresponding bpf_program starts out with + * autoload set to false. + */ + if (sec_name[0] == '?') { + prog->autoload = false; + /* from now on forget there was ? in section name */ + sec_name++; + } else { + prog->autoload = true; + } + + prog->autoattach = true; - prog->instances.fds = NULL; - prog->instances.nr = -1; + /* inherit object's log_level */ + prog->log_level = obj->log_level; prog->sec_name = strdup(sec_name); if (!prog->sec_name) @@ -591,22 +817,11 @@ bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog, if (!prog->name) goto errout; - prog->pin_name = __bpf_program__pin_name(prog); - if (!prog->pin_name) - goto errout; - prog->insns = malloc(insn_data_sz); if (!prog->insns) goto errout; memcpy(prog->insns, insn_data, insn_data_sz); - for (i = 0; i < prog->insns_cnt; i++) { - if (insn_is_subprog_call(&prog->insns[i])) { - obj->has_subcalls = true; - break; - } - } - return 0; errout: pr_warn("sec '%s': failed to allocate memory for prog '%s'\n", sec_name, name); @@ -618,27 +833,30 @@ static int bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, const char *sec_name, int sec_idx) { + Elf_Data *symbols = obj->efile.symbols; struct bpf_program *prog, *progs; void *data = sec_data->d_buf; - size_t sec_sz = sec_data->d_size, sec_off, prog_sz; - int nr_progs, err; + size_t sec_sz = sec_data->d_size, sec_off, prog_sz, nr_syms; + int nr_progs, err, i; const char *name; - GElf_Sym sym; + Elf64_Sym *sym; progs = obj->programs; nr_progs = obj->nr_programs; - sec_off = 0; + nr_syms = symbols->d_size / sizeof(Elf64_Sym); - while (sec_off < sec_sz) { - if (elf_sym_by_sec_off(obj, sec_idx, sec_off, STT_FUNC, &sym)) { - pr_warn("sec '%s': failed to find program symbol at offset %zu\n", - sec_name, sec_off); - return -LIBBPF_ERRNO__FORMAT; - } + for (i = 0; i < nr_syms; i++) { + sym = elf_sym_by_idx(obj, i); + + if (sym->st_shndx != sec_idx) + continue; + if (ELF64_ST_TYPE(sym->st_info) != STT_FUNC) + continue; - prog_sz = sym.st_size; + prog_sz = sym->st_size; + sec_off = sym->st_value; - name = elf_sym_str(obj, sym.st_name); + name = elf_sym_str(obj, sym->st_name); if (!name) { pr_warn("sec '%s': failed to get symbol name for offset %zu\n", sec_name, sec_off); @@ -651,6 +869,11 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, return -LIBBPF_ERRNO__FORMAT; } + if (sec_idx != obj->efile.text_shndx && ELF64_ST_BIND(sym->st_info) == STB_LOCAL) { + pr_warn("sec '%s': program '%s' is static and not supported\n", sec_name, name); + return -ENOTSUP; + } + pr_debug("sec '%s': found program '%s' at insn offset %zu (%zu bytes), code size %zu insns (%zu bytes)\n", sec_name, name, sec_off / BPF_INSN_SZ, sec_off, prog_sz / BPF_INSN_SZ, prog_sz); @@ -674,26 +897,25 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, if (err) return err; + if (ELF64_ST_BIND(sym->st_info) != STB_LOCAL) + prog->sym_global = true; + + /* if function is a global/weak symbol, but has restricted + * (STV_HIDDEN or STV_INTERNAL) visibility, mark its BTF FUNC + * as static to enable more permissive BPF verification mode + * with more outside context available to BPF verifier + */ + if (prog->sym_global && (ELF64_ST_VISIBILITY(sym->st_other) == STV_HIDDEN + || ELF64_ST_VISIBILITY(sym->st_other) == STV_INTERNAL)) + prog->mark_btf_static = true; + nr_progs++; obj->nr_programs = nr_progs; - - sec_off += prog_sz; } return 0; } -static __u32 get_kernel_version(void) -{ - __u32 major, minor, patch; - struct utsname info; - - uname(&info); - if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3) - return 0; - return KERNEL_VERSION(major, minor, patch); -} - static const struct btf_member * find_member_by_offset(const struct btf_type *t, __u32 bit_offset) { @@ -723,22 +945,33 @@ find_member_by_name(const struct btf *btf, const struct btf_type *t, return NULL; } +static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name, + __u16 kind, struct btf **res_btf, + struct module_btf **res_mod_btf); + #define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_" static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, const char *name, __u32 kind); static int -find_struct_ops_kern_types(const struct btf *btf, const char *tname, +find_struct_ops_kern_types(struct bpf_object *obj, const char *tname_raw, + struct module_btf **mod_btf, const struct btf_type **type, __u32 *type_id, const struct btf_type **vtype, __u32 *vtype_id, const struct btf_member **data_member) { const struct btf_type *kern_type, *kern_vtype; const struct btf_member *kern_data_member; + struct btf *btf; __s32 kern_vtype_id, kern_type_id; + char tname[256]; __u32 i; - kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT); + snprintf(tname, sizeof(tname), "%.*s", + (int)bpf_core_essential_name_len(tname_raw), tname_raw); + + kern_type_id = find_ksym_btf_id(obj, tname, BTF_KIND_STRUCT, + &btf, mod_btf); if (kern_type_id < 0) { pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n", tname); @@ -791,15 +1024,72 @@ static bool bpf_map__is_struct_ops(const struct bpf_map *map) return map->def.type == BPF_MAP_TYPE_STRUCT_OPS; } +static bool is_valid_st_ops_program(struct bpf_object *obj, + const struct bpf_program *prog) +{ + int i; + + for (i = 0; i < obj->nr_programs; i++) { + if (&obj->programs[i] == prog) + return prog->type == BPF_PROG_TYPE_STRUCT_OPS; + } + + return false; +} + +/* For each struct_ops program P, referenced from some struct_ops map M, + * enable P.autoload if there are Ms for which M.autocreate is true, + * disable P.autoload if for all Ms M.autocreate is false. + * Don't change P.autoload for programs that are not referenced from any maps. + */ +static int bpf_object_adjust_struct_ops_autoload(struct bpf_object *obj) +{ + struct bpf_program *prog, *slot_prog; + struct bpf_map *map; + int i, j, k, vlen; + + for (i = 0; i < obj->nr_programs; ++i) { + int should_load = false; + int use_cnt = 0; + + prog = &obj->programs[i]; + if (prog->type != BPF_PROG_TYPE_STRUCT_OPS) + continue; + + for (j = 0; j < obj->nr_maps; ++j) { + map = &obj->maps[j]; + if (!bpf_map__is_struct_ops(map)) + continue; + + vlen = btf_vlen(map->st_ops->type); + for (k = 0; k < vlen; ++k) { + slot_prog = map->st_ops->progs[k]; + if (prog != slot_prog) + continue; + + use_cnt++; + if (map->autocreate) + should_load = true; + } + } + if (use_cnt) + prog->autoload = should_load; + } + + return 0; +} + /* Init the map's fields that depend on kern_btf */ -static int bpf_map__init_kern_struct_ops(struct bpf_map *map, - const struct btf *btf, - const struct btf *kern_btf) +static int bpf_map__init_kern_struct_ops(struct bpf_map *map) { const struct btf_member *member, *kern_member, *kern_data_member; const struct btf_type *type, *kern_type, *kern_vtype; __u32 i, kern_type_id, kern_vtype_id, kern_data_off; + struct bpf_object *obj = map->obj; + const struct btf *btf = obj->btf; struct bpf_struct_ops *st_ops; + const struct btf *kern_btf; + struct module_btf *mod_btf; void *data, *kern_data; const char *tname; int err; @@ -807,16 +1097,19 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map, st_ops = map->st_ops; type = st_ops->type; tname = st_ops->tname; - err = find_struct_ops_kern_types(kern_btf, tname, + err = find_struct_ops_kern_types(obj, tname, &mod_btf, &kern_type, &kern_type_id, &kern_vtype, &kern_vtype_id, &kern_data_member); if (err) return err; + kern_btf = mod_btf ? mod_btf->btf : obj->btf_vmlinux; + pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n", map->name, st_ops->type_id, kern_type_id, kern_vtype_id); + map->mod_btf_fd = mod_btf ? mod_btf->fd : -1; map->def.value_size = kern_vtype->size; map->btf_vmlinux_value_type_id = kern_vtype_id; @@ -874,26 +1167,59 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map, if (btf_is_ptr(mtype)) { struct bpf_program *prog; - mtype = skip_mods_and_typedefs(btf, mtype->type, &mtype_id); + /* Update the value from the shadow type */ + prog = *(void **)mdata; + st_ops->progs[i] = prog; + if (!prog) + continue; + if (!is_valid_st_ops_program(obj, prog)) { + pr_warn("struct_ops init_kern %s: member %s is not a struct_ops program\n", + map->name, mname); + return -ENOTSUP; + } + kern_mtype = skip_mods_and_typedefs(kern_btf, kern_mtype->type, &kern_mtype_id); - if (!btf_is_func_proto(mtype) || - !btf_is_func_proto(kern_mtype)) { - pr_warn("struct_ops init_kern %s: non func ptr %s is not supported\n", + + /* mtype->type must be a func_proto which was + * guaranteed in bpf_object__collect_st_ops_relos(), + * so only check kern_mtype for func_proto here. + */ + if (!btf_is_func_proto(kern_mtype)) { + pr_warn("struct_ops init_kern %s: kernel member %s is not a func ptr\n", map->name, mname); return -ENOTSUP; } - prog = st_ops->progs[i]; - if (!prog) { - pr_debug("struct_ops init_kern %s: func ptr %s is not set\n", - map->name, mname); - continue; + if (mod_btf) + prog->attach_btf_obj_fd = mod_btf->fd; + + /* if we haven't yet processed this BPF program, record proper + * attach_btf_id and member_idx + */ + if (!prog->attach_btf_id) { + prog->attach_btf_id = kern_type_id; + prog->expected_attach_type = kern_member_idx; } - prog->attach_btf_id = kern_type_id; - prog->expected_attach_type = kern_member_idx; + /* struct_ops BPF prog can be re-used between multiple + * .struct_ops & .struct_ops.link as long as it's the + * same struct_ops struct definition and the same + * function pointer field + */ + if (prog->attach_btf_id != kern_type_id) { + pr_warn("struct_ops init_kern %s func ptr %s: invalid reuse of prog %s in sec %s with type %u: attach_btf_id %u != kern_type_id %u\n", + map->name, mname, prog->name, prog->sec_name, prog->type, + prog->attach_btf_id, kern_type_id); + return -EINVAL; + } + if (prog->expected_attach_type != kern_member_idx) { + pr_warn("struct_ops init_kern %s func ptr %s: invalid reuse of prog %s in sec %s with type %u: expected_attach_type %u != kern_member_idx %u\n", + map->name, mname, prog->name, prog->sec_name, prog->type, + prog->expected_attach_type, kern_member_idx); + return -EINVAL; + } st_ops->kern_func_off[i] = kern_data_off + kern_moff; @@ -934,8 +1260,10 @@ static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj) if (!bpf_map__is_struct_ops(map)) continue; - err = bpf_map__init_kern_struct_ops(map, obj->btf, - obj->btf_vmlinux); + if (!map->autocreate) + continue; + + err = bpf_map__init_kern_struct_ops(map); if (err) return err; } @@ -943,7 +1271,8 @@ static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj) return 0; } -static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) +static int init_struct_ops_maps(struct bpf_object *obj, const char *sec_name, + int shndx, Elf_Data *data) { const struct btf_type *type, *datasec; const struct btf_var_secinfo *vsi; @@ -954,15 +1283,15 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) struct bpf_map *map; __u32 i; - if (obj->efile.st_ops_shndx == -1) + if (shndx == -1) return 0; btf = obj->btf; - datasec_id = btf__find_by_name_kind(btf, STRUCT_OPS_SEC, + datasec_id = btf__find_by_name_kind(btf, sec_name, BTF_KIND_DATASEC); if (datasec_id < 0) { pr_warn("struct_ops init: DATASEC %s not found\n", - STRUCT_OPS_SEC); + sec_name); return -EINVAL; } @@ -975,7 +1304,7 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) type_id = btf__resolve_type(obj->btf, vsi->type); if (type_id < 0) { pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n", - vsi->type, STRUCT_OPS_SEC); + vsi->type, sec_name); return -EINVAL; } @@ -994,16 +1323,27 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) if (IS_ERR(map)) return PTR_ERR(map); - map->sec_idx = obj->efile.st_ops_shndx; + map->sec_idx = shndx; map->sec_offset = vsi->offset; map->name = strdup(var_name); if (!map->name) return -ENOMEM; + map->btf_value_type_id = type_id; + + /* Follow same convention as for programs autoload: + * SEC("?.struct_ops") means map is not created by default. + */ + if (sec_name[0] == '?') { + map->autocreate = false; + /* from now on forget there was ? in section name */ + sec_name++; + } map->def.type = BPF_MAP_TYPE_STRUCT_OPS; map->def.key_size = sizeof(int); map->def.value_size = type->size; map->def.max_entries = 1; + map->def.map_flags = strcmp(sec_name, STRUCT_OPS_LINK_SEC) == 0 ? BPF_F_LINK : 0; map->st_ops = calloc(1, sizeof(*map->st_ops)); if (!map->st_ops) @@ -1016,14 +1356,14 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off) return -ENOMEM; - if (vsi->offset + type->size > obj->efile.st_ops_data->d_size) { + if (vsi->offset + type->size > data->d_size) { pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n", - var_name, STRUCT_OPS_SEC); + var_name, sec_name); return -EINVAL; } memcpy(st_ops->data, - obj->efile.st_ops_data->d_buf + vsi->offset, + data->d_buf + vsi->offset, type->size); st_ops->tname = tname; st_ops->type = type; @@ -1036,6 +1376,29 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) return 0; } +static int bpf_object_init_struct_ops(struct bpf_object *obj) +{ + const char *sec_name; + int sec_idx, err; + + for (sec_idx = 0; sec_idx < obj->efile.sec_cnt; ++sec_idx) { + struct elf_sec_desc *desc = &obj->efile.secs[sec_idx]; + + if (desc->sec_type != SEC_ST_OPS) + continue; + + sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); + if (!sec_name) + return -LIBBPF_ERRNO__FORMAT; + + err = init_struct_ops_maps(obj, sec_name, sec_idx, desc->data); + if (err) + return err; + } + + return 0; +} + static struct bpf_object *bpf_object__new(const char *path, const void *obj_buf, size_t obj_buf_sz, @@ -1052,12 +1415,10 @@ static struct bpf_object *bpf_object__new(const char *path, strcpy(obj->path, path); if (obj_name) { - strncpy(obj->name, obj_name, sizeof(obj->name) - 1); - obj->name[sizeof(obj->name) - 1] = 0; + libbpf_strlcpy(obj->name, obj_name, sizeof(obj->name)); } else { /* Using basename() GNU version which doesn't modify arg. */ - strncpy(obj->name, basename((void *)path), - sizeof(obj->name) - 1); + libbpf_strlcpy(obj->name, basename((void *)path), sizeof(obj->name)); end = strchr(obj->name, '.'); if (end) *end = 0; @@ -1072,69 +1433,48 @@ static struct bpf_object *bpf_object__new(const char *path, */ obj->efile.obj_buf = obj_buf; obj->efile.obj_buf_sz = obj_buf_sz; - obj->efile.maps_shndx = -1; obj->efile.btf_maps_shndx = -1; - obj->efile.data_shndx = -1; - obj->efile.rodata_shndx = -1; - obj->efile.bss_shndx = -1; - obj->efile.st_ops_shndx = -1; obj->kconfig_map_idx = -1; - obj->rodata_map_idx = -1; obj->kern_version = get_kernel_version(); obj->loaded = false; - INIT_LIST_HEAD(&obj->list); - list_add(&obj->list, &bpf_objects_list); return obj; } static void bpf_object__elf_finish(struct bpf_object *obj) { - if (!obj_elf_valid(obj)) + if (!obj->efile.elf) return; - if (obj->efile.elf) { - elf_end(obj->efile.elf); - obj->efile.elf = NULL; - } + elf_end(obj->efile.elf); + obj->efile.elf = NULL; obj->efile.symbols = NULL; - obj->efile.data = NULL; - obj->efile.rodata = NULL; - obj->efile.bss = NULL; - obj->efile.st_ops_data = NULL; + obj->efile.arena_data = NULL; - zfree(&obj->efile.reloc_sects); - obj->efile.nr_reloc_sects = 0; + zfree(&obj->efile.secs); + obj->efile.sec_cnt = 0; zclose(obj->efile.fd); obj->efile.obj_buf = NULL; obj->efile.obj_buf_sz = 0; } -/* if libelf is old and doesn't support mmap(), fall back to read() */ -#ifndef ELF_C_READ_MMAP -#define ELF_C_READ_MMAP ELF_C_READ -#endif - static int bpf_object__elf_init(struct bpf_object *obj) { + Elf64_Ehdr *ehdr; int err = 0; - GElf_Ehdr *ep; + Elf *elf; - if (obj_elf_valid(obj)) { + if (obj->efile.elf) { pr_warn("elf: init internal error\n"); return -LIBBPF_ERRNO__LIBELF; } if (obj->efile.obj_buf_sz > 0) { - /* - * obj_buf should have been validated by - * bpf_object__open_buffer(). - */ - obj->efile.elf = elf_memory((char *)obj->efile.obj_buf, - obj->efile.obj_buf_sz); + /* obj_buf should have been validated by bpf_object__open_mem(). */ + elf = elf_memory((char *)obj->efile.obj_buf, obj->efile.obj_buf_sz); } else { - obj->efile.fd = open(obj->path, O_RDONLY); + obj->efile.fd = open(obj->path, O_RDONLY | O_CLOEXEC); if (obj->efile.fd < 0) { char errmsg[STRERR_BUFSIZE], *cp; @@ -1144,39 +1484,53 @@ static int bpf_object__elf_init(struct bpf_object *obj) return err; } - obj->efile.elf = elf_begin(obj->efile.fd, ELF_C_READ_MMAP, NULL); + elf = elf_begin(obj->efile.fd, ELF_C_READ_MMAP, NULL); } - if (!obj->efile.elf) { + if (!elf) { pr_warn("elf: failed to open %s as ELF file: %s\n", obj->path, elf_errmsg(-1)); err = -LIBBPF_ERRNO__LIBELF; goto errout; } - if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) { + obj->efile.elf = elf; + + if (elf_kind(elf) != ELF_K_ELF) { + err = -LIBBPF_ERRNO__FORMAT; + pr_warn("elf: '%s' is not a proper ELF object\n", obj->path); + goto errout; + } + + if (gelf_getclass(elf) != ELFCLASS64) { + err = -LIBBPF_ERRNO__FORMAT; + pr_warn("elf: '%s' is not a 64-bit ELF object\n", obj->path); + goto errout; + } + + obj->efile.ehdr = ehdr = elf64_getehdr(elf); + if (!obj->efile.ehdr) { pr_warn("elf: failed to get ELF header from %s: %s\n", obj->path, elf_errmsg(-1)); err = -LIBBPF_ERRNO__FORMAT; goto errout; } - ep = &obj->efile.ehdr; - if (elf_getshdrstrndx(obj->efile.elf, &obj->efile.shstrndx)) { + if (elf_getshdrstrndx(elf, &obj->efile.shstrndx)) { pr_warn("elf: failed to get section names section index for %s: %s\n", obj->path, elf_errmsg(-1)); err = -LIBBPF_ERRNO__FORMAT; goto errout; } - /* Elf is corrupted/truncated, avoid calling elf_strptr. */ - if (!elf_rawdata(elf_getscn(obj->efile.elf, obj->efile.shstrndx), NULL)) { + /* ELF is corrupted/truncated, avoid calling elf_strptr. */ + if (!elf_rawdata(elf_getscn(elf, obj->efile.shstrndx), NULL)) { pr_warn("elf: failed to get section names strings from %s: %s\n", obj->path, elf_errmsg(-1)); - return -LIBBPF_ERRNO__FORMAT; + err = -LIBBPF_ERRNO__FORMAT; + goto errout; } /* Old LLVM set e_machine to EM_NONE */ - if (ep->e_type != ET_REL || - (ep->e_machine && ep->e_machine != EM_BPF)) { + if (ehdr->e_type != ET_REL || (ehdr->e_machine && ehdr->e_machine != EM_BPF)) { pr_warn("elf: %s is not a valid eBPF object file\n", obj->path); err = -LIBBPF_ERRNO__FORMAT; goto errout; @@ -1190,11 +1544,11 @@ errout: static int bpf_object__check_endianness(struct bpf_object *obj) { -#if __BYTE_ORDER == __LITTLE_ENDIAN - if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB) +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + if (obj->efile.ehdr->e_ident[EI_DATA] == ELFDATA2LSB) return 0; -#elif __BYTE_ORDER == __BIG_ENDIAN - if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB) +#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ + if (obj->efile.ehdr->e_ident[EI_DATA] == ELFDATA2MSB) return 0; #else # error "Unrecognized __BYTE_ORDER__" @@ -1206,7 +1560,14 @@ static int bpf_object__check_endianness(struct bpf_object *obj) static int bpf_object__init_license(struct bpf_object *obj, void *data, size_t size) { - memcpy(obj->license, data, min(size, sizeof(obj->license) - 1)); + if (!data) { + pr_warn("invalid license section in %s\n", obj->path); + return -LIBBPF_ERRNO__FORMAT; + } + /* libbpf_strlcpy() only copies first N - 1 bytes, so size + 1 won't + * go over allowed ELF data section buffer + */ + libbpf_strlcpy(obj->license, data, min(size + 1, sizeof(obj->license))); pr_debug("license of %s is %s\n", obj->path, obj->license); return 0; } @@ -1216,7 +1577,7 @@ bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size) { __u32 kver; - if (size != sizeof(kver)) { + if (!data || size != sizeof(kver)) { pr_warn("invalid kver section in %s\n", obj->path); return -LIBBPF_ERRNO__FORMAT; } @@ -1234,128 +1595,197 @@ static bool bpf_map_type__is_map_in_map(enum bpf_map_type type) return false; } -int bpf_object__section_size(const struct bpf_object *obj, const char *name, - __u32 *size) +static int find_elf_sec_sz(const struct bpf_object *obj, const char *name, __u32 *size) { - int ret = -ENOENT; + Elf_Data *data; + Elf_Scn *scn; - *size = 0; - if (!name) { + if (!name) return -EINVAL; - } else if (!strcmp(name, DATA_SEC)) { - if (obj->efile.data) - *size = obj->efile.data->d_size; - } else if (!strcmp(name, BSS_SEC)) { - if (obj->efile.bss) - *size = obj->efile.bss->d_size; - } else if (!strcmp(name, RODATA_SEC)) { - if (obj->efile.rodata) - *size = obj->efile.rodata->d_size; - } else if (!strcmp(name, STRUCT_OPS_SEC)) { - if (obj->efile.st_ops_data) - *size = obj->efile.st_ops_data->d_size; - } else { - Elf_Scn *scn = elf_sec_by_name(obj, name); - Elf_Data *data = elf_sec_data(obj, scn); - if (data) { - ret = 0; /* found it */ - *size = data->d_size; - } + scn = elf_sec_by_name(obj, name); + data = elf_sec_data(obj, scn); + if (data) { + *size = data->d_size; + return 0; /* found it */ } - return *size ? 0 : ret; + return -ENOENT; } -int bpf_object__variable_offset(const struct bpf_object *obj, const char *name, - __u32 *off) +static Elf64_Sym *find_elf_var_sym(const struct bpf_object *obj, const char *name) { Elf_Data *symbols = obj->efile.symbols; const char *sname; size_t si; - if (!name || !off) - return -EINVAL; - - for (si = 0; si < symbols->d_size / sizeof(GElf_Sym); si++) { - GElf_Sym sym; + for (si = 0; si < symbols->d_size / sizeof(Elf64_Sym); si++) { + Elf64_Sym *sym = elf_sym_by_idx(obj, si); - if (!gelf_getsym(symbols, si, &sym)) + if (ELF64_ST_TYPE(sym->st_info) != STT_OBJECT) continue; - if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL || - GELF_ST_TYPE(sym.st_info) != STT_OBJECT) + + if (ELF64_ST_BIND(sym->st_info) != STB_GLOBAL && + ELF64_ST_BIND(sym->st_info) != STB_WEAK) continue; - sname = elf_sym_str(obj, sym.st_name); + sname = elf_sym_str(obj, sym->st_name); if (!sname) { - pr_warn("failed to get sym name string for var %s\n", - name); - return -EIO; - } - if (strcmp(name, sname) == 0) { - *off = sym.st_value; - return 0; + pr_warn("failed to get sym name string for var %s\n", name); + return ERR_PTR(-EIO); } + if (strcmp(name, sname) == 0) + return sym; } - return -ENOENT; + return ERR_PTR(-ENOENT); } -static struct bpf_map *bpf_object__add_map(struct bpf_object *obj) +/* Some versions of Android don't provide memfd_create() in their libc + * implementation, so avoid complications and just go straight to Linux + * syscall. + */ +static int sys_memfd_create(const char *name, unsigned flags) { - struct bpf_map *new_maps; - size_t new_cap; - int i; + return syscall(__NR_memfd_create, name, flags); +} - if (obj->nr_maps < obj->maps_cap) - return &obj->maps[obj->nr_maps++]; +static int create_placeholder_fd(void) +{ + int fd; - new_cap = max((size_t)4, obj->maps_cap * 3 / 2); - new_maps = libbpf_reallocarray(obj->maps, new_cap, sizeof(*obj->maps)); - if (!new_maps) { - pr_warn("alloc maps for object failed\n"); - return ERR_PTR(-ENOMEM); - } + fd = ensure_good_fd(sys_memfd_create("libbpf-placeholder-fd", MFD_CLOEXEC)); + if (fd < 0) + return -errno; + return fd; +} - obj->maps_cap = new_cap; - obj->maps = new_maps; +static struct bpf_map *bpf_object__add_map(struct bpf_object *obj) +{ + struct bpf_map *map; + int err; - /* zero out new maps */ - memset(obj->maps + obj->nr_maps, 0, - (obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps)); - /* - * fill all fd with -1 so won't close incorrect fd (fd=0 is stdin) - * when failure (zclose won't close negative fd)). + err = libbpf_ensure_mem((void **)&obj->maps, &obj->maps_cap, + sizeof(*obj->maps), obj->nr_maps + 1); + if (err) + return ERR_PTR(err); + + map = &obj->maps[obj->nr_maps++]; + map->obj = obj; + /* Preallocate map FD without actually creating BPF map just yet. + * These map FD "placeholders" will be reused later without changing + * FD value when map is actually created in the kernel. + * + * This is useful to be able to perform BPF program relocations + * without having to create BPF maps before that step. This allows us + * to finalize and load BTF very late in BPF object's loading phase, + * right before BPF maps have to be created and BPF programs have to + * be loaded. By having these map FD placeholders we can perform all + * the sanitizations, relocations, and any other adjustments before we + * start creating actual BPF kernel objects (BTF, maps, progs). */ - for (i = obj->nr_maps; i < obj->maps_cap; i++) { - obj->maps[i].fd = -1; - obj->maps[i].inner_map_fd = -1; - } + map->fd = create_placeholder_fd(); + if (map->fd < 0) + return ERR_PTR(map->fd); + map->inner_map_fd = -1; + map->autocreate = true; - return &obj->maps[obj->nr_maps++]; + return map; } -static size_t bpf_map_mmap_sz(const struct bpf_map *map) +static size_t array_map_mmap_sz(unsigned int value_sz, unsigned int max_entries) { - long page_sz = sysconf(_SC_PAGE_SIZE); + const long page_sz = sysconf(_SC_PAGE_SIZE); size_t map_sz; - map_sz = (size_t)roundup(map->def.value_size, 8) * map->def.max_entries; + map_sz = (size_t)roundup(value_sz, 8) * max_entries; map_sz = roundup(map_sz, page_sz); return map_sz; } -static char *internal_map_name(struct bpf_object *obj, - enum libbpf_map_type type) +static size_t bpf_map_mmap_sz(const struct bpf_map *map) +{ + const long page_sz = sysconf(_SC_PAGE_SIZE); + + switch (map->def.type) { + case BPF_MAP_TYPE_ARRAY: + return array_map_mmap_sz(map->def.value_size, map->def.max_entries); + case BPF_MAP_TYPE_ARENA: + return page_sz * map->def.max_entries; + default: + return 0; /* not supported */ + } +} + +static int bpf_map_mmap_resize(struct bpf_map *map, size_t old_sz, size_t new_sz) +{ + void *mmaped; + + if (!map->mmaped) + return -EINVAL; + + if (old_sz == new_sz) + return 0; + + mmaped = mmap(NULL, new_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); + if (mmaped == MAP_FAILED) + return -errno; + + memcpy(mmaped, map->mmaped, min(old_sz, new_sz)); + munmap(map->mmaped, old_sz); + map->mmaped = mmaped; + return 0; +} + +static char *internal_map_name(struct bpf_object *obj, const char *real_name) { char map_name[BPF_OBJ_NAME_LEN], *p; - const char *sfx = libbpf_type_to_btf_name[type]; - int sfx_len = max((size_t)7, strlen(sfx)); - int pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1, - strlen(obj->name)); + int pfx_len, sfx_len = max((size_t)7, strlen(real_name)); + + /* This is one of the more confusing parts of libbpf for various + * reasons, some of which are historical. The original idea for naming + * internal names was to include as much of BPF object name prefix as + * possible, so that it can be distinguished from similar internal + * maps of a different BPF object. + * As an example, let's say we have bpf_object named 'my_object_name' + * and internal map corresponding to '.rodata' ELF section. The final + * map name advertised to user and to the kernel will be + * 'my_objec.rodata', taking first 8 characters of object name and + * entire 7 characters of '.rodata'. + * Somewhat confusingly, if internal map ELF section name is shorter + * than 7 characters, e.g., '.bss', we still reserve 7 characters + * for the suffix, even though we only have 4 actual characters, and + * resulting map will be called 'my_objec.bss', not even using all 15 + * characters allowed by the kernel. Oh well, at least the truncated + * object name is somewhat consistent in this case. But if the map + * name is '.kconfig', we'll still have entirety of '.kconfig' added + * (8 chars) and thus will be left with only first 7 characters of the + * object name ('my_obje'). Happy guessing, user, that the final map + * name will be "my_obje.kconfig". + * Now, with libbpf starting to support arbitrarily named .rodata.* + * and .data.* data sections, it's possible that ELF section name is + * longer than allowed 15 chars, so we now need to be careful to take + * only up to 15 first characters of ELF name, taking no BPF object + * name characters at all. So '.rodata.abracadabra' will result in + * '.rodata.abracad' kernel and user-visible name. + * We need to keep this convoluted logic intact for .data, .bss and + * .rodata maps, but for new custom .data.custom and .rodata.custom + * maps we use their ELF names as is, not prepending bpf_object name + * in front. We still need to truncate them to 15 characters for the + * kernel. Full name can be recovered for such maps by using DATASEC + * BTF type associated with such map's value type, though. + */ + if (sfx_len >= BPF_OBJ_NAME_LEN) + sfx_len = BPF_OBJ_NAME_LEN - 1; + + /* if there are two or more dots in map name, it's a custom dot map */ + if (strchr(real_name + 1, '.') != NULL) + pfx_len = 0; + else + pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1, strlen(obj->name)); snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name, - sfx_len, libbpf_type_to_btf_name[type]); + sfx_len, real_name); /* sanitise map name to characters allowed by kernel */ for (p = map_name; *p && p < map_name + sizeof(map_name); p++) @@ -1366,11 +1796,46 @@ static char *internal_map_name(struct bpf_object *obj, } static int +map_fill_btf_type_info(struct bpf_object *obj, struct bpf_map *map); + +/* Internal BPF map is mmap()'able only if at least one of corresponding + * DATASEC's VARs are to be exposed through BPF skeleton. I.e., it's a GLOBAL + * variable and it's not marked as __hidden (which turns it into, effectively, + * a STATIC variable). + */ +static bool map_is_mmapable(struct bpf_object *obj, struct bpf_map *map) +{ + const struct btf_type *t, *vt; + struct btf_var_secinfo *vsi; + int i, n; + + if (!map->btf_value_type_id) + return false; + + t = btf__type_by_id(obj->btf, map->btf_value_type_id); + if (!btf_is_datasec(t)) + return false; + + vsi = btf_var_secinfos(t); + for (i = 0, n = btf_vlen(t); i < n; i++, vsi++) { + vt = btf__type_by_id(obj->btf, vsi->type); + if (!btf_is_var(vt)) + continue; + + if (btf_var(vt)->linkage != BTF_VAR_STATIC) + return true; + } + + return false; +} + +static int bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, - int sec_idx, void *data, size_t data_sz) + const char *real_name, int sec_idx, void *data, size_t data_sz) { struct bpf_map_def *def; struct bpf_map *map; + size_t mmap_sz; int err; map = bpf_object__add_map(obj); @@ -1380,9 +1845,11 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, map->libbpf_type = type; map->sec_idx = sec_idx; map->sec_offset = 0; - map->name = internal_map_name(obj, type); - if (!map->name) { - pr_warn("failed to alloc map name\n"); + map->real_name = strdup(real_name); + map->name = internal_map_name(obj, real_name); + if (!map->real_name || !map->name) { + zfree(&map->real_name); + zfree(&map->name); return -ENOMEM; } @@ -1392,19 +1859,26 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, def->value_size = data_sz; def->max_entries = 1; def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_KCONFIG - ? BPF_F_RDONLY_PROG : 0; - def->map_flags |= BPF_F_MMAPABLE; + ? BPF_F_RDONLY_PROG : 0; + + /* failures are fine because of maps like .rodata.str1.1 */ + (void) map_fill_btf_type_info(obj, map); + + if (map_is_mmapable(obj, map)) + def->map_flags |= BPF_F_MMAPABLE; pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n", map->name, map->sec_idx, map->sec_offset, def->map_flags); - map->mmaped = mmap(NULL, bpf_map_mmap_sz(map), PROT_READ | PROT_WRITE, + mmap_sz = bpf_map_mmap_sz(map); + map->mmaped = mmap(NULL, mmap_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (map->mmaped == MAP_FAILED) { err = -errno; map->mmaped = NULL; pr_warn("failed to alloc map '%s' content buffer: %d\n", map->name, err); + zfree(&map->real_name); zfree(&map->name); return err; } @@ -1418,34 +1892,47 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, static int bpf_object__init_global_data_maps(struct bpf_object *obj) { - int err; + struct elf_sec_desc *sec_desc; + const char *sec_name; + int err = 0, sec_idx; /* * Populate obj->maps with libbpf internal maps. */ - if (obj->efile.data_shndx >= 0) { - err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA, - obj->efile.data_shndx, - obj->efile.data->d_buf, - obj->efile.data->d_size); - if (err) - return err; - } - if (obj->efile.rodata_shndx >= 0) { - err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA, - obj->efile.rodata_shndx, - obj->efile.rodata->d_buf, - obj->efile.rodata->d_size); - if (err) - return err; + for (sec_idx = 1; sec_idx < obj->efile.sec_cnt; sec_idx++) { + sec_desc = &obj->efile.secs[sec_idx]; - obj->rodata_map_idx = obj->nr_maps - 1; - } - if (obj->efile.bss_shndx >= 0) { - err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS, - obj->efile.bss_shndx, - NULL, - obj->efile.bss->d_size); + /* Skip recognized sections with size 0. */ + if (!sec_desc->data || sec_desc->data->d_size == 0) + continue; + + switch (sec_desc->sec_type) { + case SEC_DATA: + sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA, + sec_name, sec_idx, + sec_desc->data->d_buf, + sec_desc->data->d_size); + break; + case SEC_RODATA: + obj->has_rodata = true; + sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA, + sec_name, sec_idx, + sec_desc->data->d_buf, + sec_desc->data->d_size); + break; + case SEC_BSS: + sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS, + sec_name, sec_idx, + NULL, + sec_desc->data->d_size); + break; + default: + /* skip */ + break; + } if (err) return err; } @@ -1471,7 +1958,7 @@ static int set_kcfg_value_tri(struct extern_desc *ext, void *ext_val, switch (ext->kcfg.type) { case KCFG_BOOL: if (value == 'm') { - pr_warn("extern (kcfg) %s=%c should be tristate or char\n", + pr_warn("extern (kcfg) '%s': value '%c' implies tristate or char type\n", ext->name, value); return -EINVAL; } @@ -1492,7 +1979,7 @@ static int set_kcfg_value_tri(struct extern_desc *ext, void *ext_val, case KCFG_INT: case KCFG_CHAR_ARR: default: - pr_warn("extern (kcfg) %s=%c should be bool, tristate, or char\n", + pr_warn("extern (kcfg) '%s': value '%c' implies bool, tristate, or char type\n", ext->name, value); return -EINVAL; } @@ -1506,7 +1993,8 @@ static int set_kcfg_value_str(struct extern_desc *ext, char *ext_val, size_t len; if (ext->kcfg.type != KCFG_CHAR_ARR) { - pr_warn("extern (kcfg) %s=%s should be char array\n", ext->name, value); + pr_warn("extern (kcfg) '%s': value '%s' implies char array type\n", + ext->name, value); return -EINVAL; } @@ -1520,7 +2008,7 @@ static int set_kcfg_value_str(struct extern_desc *ext, char *ext_val, /* strip quotes */ len -= 2; if (len >= ext->kcfg.sz) { - pr_warn("extern (kcfg) '%s': long string config %s of (%zu bytes) truncated to %d bytes\n", + pr_warn("extern (kcfg) '%s': long string '%s' of (%zu bytes) truncated to %d bytes\n", ext->name, value, len, ext->kcfg.sz - 1); len = ext->kcfg.sz - 1; } @@ -1577,23 +2065,38 @@ static bool is_kcfg_value_in_range(const struct extern_desc *ext, __u64 v) static int set_kcfg_value_num(struct extern_desc *ext, void *ext_val, __u64 value) { - if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR) { - pr_warn("extern (kcfg) %s=%llu should be integer\n", + if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR && + ext->kcfg.type != KCFG_BOOL) { + pr_warn("extern (kcfg) '%s': value '%llu' implies integer, char, or boolean type\n", + ext->name, (unsigned long long)value); + return -EINVAL; + } + if (ext->kcfg.type == KCFG_BOOL && value > 1) { + pr_warn("extern (kcfg) '%s': value '%llu' isn't boolean compatible\n", ext->name, (unsigned long long)value); return -EINVAL; + } if (!is_kcfg_value_in_range(ext, value)) { - pr_warn("extern (kcfg) %s=%llu value doesn't fit in %d bytes\n", + pr_warn("extern (kcfg) '%s': value '%llu' doesn't fit in %d bytes\n", ext->name, (unsigned long long)value, ext->kcfg.sz); return -ERANGE; } switch (ext->kcfg.sz) { - case 1: *(__u8 *)ext_val = value; break; - case 2: *(__u16 *)ext_val = value; break; - case 4: *(__u32 *)ext_val = value; break; - case 8: *(__u64 *)ext_val = value; break; - default: - return -EINVAL; + case 1: + *(__u8 *)ext_val = value; + break; + case 2: + *(__u16 *)ext_val = value; + break; + case 4: + *(__u32 *)ext_val = value; + break; + case 8: + *(__u64 *)ext_val = value; + break; + default: + return -EINVAL; } ext->is_set = true; return 0; @@ -1608,7 +2111,7 @@ static int bpf_object__process_kconfig_line(struct bpf_object *obj, void *ext_val; __u64 num; - if (strncmp(buf, "CONFIG_", 7)) + if (!str_has_pfx(buf, "CONFIG_")) return 0; sep = strchr(buf, '='); @@ -1647,16 +2150,19 @@ static int bpf_object__process_kconfig_line(struct bpf_object *obj, /* assume integer */ err = parse_u64(value, &num); if (err) { - pr_warn("extern (kcfg) %s=%s should be integer\n", - ext->name, value); + pr_warn("extern (kcfg) '%s': value '%s' isn't a valid integer\n", ext->name, value); return err; } + if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR) { + pr_warn("extern (kcfg) '%s': value '%s' implies integer type\n", ext->name, value); + return -EINVAL; + } err = set_kcfg_value_num(ext, ext_val, num); break; } if (err) return err; - pr_debug("extern (kcfg) %s=%s\n", ext->name, value); + pr_debug("extern (kcfg) '%s': set to %s\n", ext->name, value); return 0; } @@ -1675,9 +2181,9 @@ static int bpf_object__read_kconfig_file(struct bpf_object *obj, void *data) return -ENAMETOOLONG; /* gzopen also accepts uncompressed files. */ - file = gzopen(buf, "r"); + file = gzopen(buf, "re"); if (!file) - file = gzopen("/proc/config.gz", "r"); + file = gzopen("/proc/config.gz", "re"); if (!file) { pr_warn("failed to open system Kconfig\n"); @@ -1742,7 +2248,7 @@ static int bpf_object__init_kconfig_map(struct bpf_object *obj) map_sz = last_ext->kcfg.data_off + last_ext->kcfg.sz; err = bpf_object__init_internal_map(obj, LIBBPF_MAP_KCONFIG, - obj->efile.symbols_shndx, + ".kconfig", obj->efile.symbols_shndx, NULL, map_sz); if (err) return err; @@ -1752,130 +2258,7 @@ static int bpf_object__init_kconfig_map(struct bpf_object *obj) return 0; } -static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict) -{ - Elf_Data *symbols = obj->efile.symbols; - int i, map_def_sz = 0, nr_maps = 0, nr_syms; - Elf_Data *data = NULL; - Elf_Scn *scn; - - if (obj->efile.maps_shndx < 0) - return 0; - - if (!symbols) - return -EINVAL; - - - scn = elf_sec_by_idx(obj, obj->efile.maps_shndx); - data = elf_sec_data(obj, scn); - if (!scn || !data) { - pr_warn("elf: failed to get legacy map definitions for %s\n", - obj->path); - return -EINVAL; - } - - /* - * Count number of maps. Each map has a name. - * Array of maps is not supported: only the first element is - * considered. - * - * TODO: Detect array of map and report error. - */ - nr_syms = symbols->d_size / sizeof(GElf_Sym); - for (i = 0; i < nr_syms; i++) { - GElf_Sym sym; - - if (!gelf_getsym(symbols, i, &sym)) - continue; - if (sym.st_shndx != obj->efile.maps_shndx) - continue; - nr_maps++; - } - /* Assume equally sized map definitions */ - pr_debug("elf: found %d legacy map definitions (%zd bytes) in %s\n", - nr_maps, data->d_size, obj->path); - - if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) { - pr_warn("elf: unable to determine legacy map definition size in %s\n", - obj->path); - return -EINVAL; - } - map_def_sz = data->d_size / nr_maps; - - /* Fill obj->maps using data in "maps" section. */ - for (i = 0; i < nr_syms; i++) { - GElf_Sym sym; - const char *map_name; - struct bpf_map_def *def; - struct bpf_map *map; - - if (!gelf_getsym(symbols, i, &sym)) - continue; - if (sym.st_shndx != obj->efile.maps_shndx) - continue; - - map = bpf_object__add_map(obj); - if (IS_ERR(map)) - return PTR_ERR(map); - - map_name = elf_sym_str(obj, sym.st_name); - if (!map_name) { - pr_warn("failed to get map #%d name sym string for obj %s\n", - i, obj->path); - return -LIBBPF_ERRNO__FORMAT; - } - - map->libbpf_type = LIBBPF_MAP_UNSPEC; - map->sec_idx = sym.st_shndx; - map->sec_offset = sym.st_value; - pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n", - map_name, map->sec_idx, map->sec_offset); - if (sym.st_value + map_def_sz > data->d_size) { - pr_warn("corrupted maps section in %s: last map \"%s\" too small\n", - obj->path, map_name); - return -EINVAL; - } - - map->name = strdup(map_name); - if (!map->name) { - pr_warn("failed to alloc map name\n"); - return -ENOMEM; - } - pr_debug("map %d is \"%s\"\n", i, map->name); - def = (struct bpf_map_def *)(data->d_buf + sym.st_value); - /* - * If the definition of the map in the object file fits in - * bpf_map_def, copy it. Any extra fields in our version - * of bpf_map_def will default to zero as a result of the - * calloc above. - */ - if (map_def_sz <= sizeof(struct bpf_map_def)) { - memcpy(&map->def, def, map_def_sz); - } else { - /* - * Here the map structure being read is bigger than what - * we expect, truncate if the excess bits are all zero. - * If they are not zero, reject this map as - * incompatible. - */ - char *b; - - for (b = ((char *)def) + sizeof(struct bpf_map_def); - b < ((char *)def) + map_def_sz; b++) { - if (*b != 0) { - pr_warn("maps section in %s: \"%s\" has unrecognized, non-zero options\n", - obj->path, map_name); - if (strict) - return -EINVAL; - } - } - memcpy(&map->def, def, sizeof(struct bpf_map_def)); - } - } - return 0; -} - -static const struct btf_type * +const struct btf_type * skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id) { const struct btf_type *t = btf__type_by_id(btf, id); @@ -1906,9 +2289,9 @@ resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id) return btf_is_func_proto(t) ? t : NULL; } -static const char *btf_kind_str(const struct btf_type *t) +static const char *__btf_kind_str(__u16 kind) { - switch (btf_kind(t)) { + switch (kind) { case BTF_KIND_UNKN: return "void"; case BTF_KIND_INT: return "int"; case BTF_KIND_PTR: return "ptr"; @@ -1925,10 +2308,19 @@ static const char *btf_kind_str(const struct btf_type *t) case BTF_KIND_FUNC_PROTO: return "func_proto"; case BTF_KIND_VAR: return "var"; case BTF_KIND_DATASEC: return "datasec"; + case BTF_KIND_FLOAT: return "float"; + case BTF_KIND_DECL_TAG: return "decl_tag"; + case BTF_KIND_TYPE_TAG: return "type_tag"; + case BTF_KIND_ENUM64: return "enum64"; default: return "unknown"; } } +const char *btf_kind_str(const struct btf_type *t) +{ + return __btf_kind_str(btf_kind(t)); +} + /* * Fetch integer attribute of BTF map definition. Such attributes are * represented using a pointer to an array, in which dimensionality of array @@ -1966,271 +2358,410 @@ static bool get_map_field_int(const char *map_name, const struct btf *btf, return true; } -static int build_map_pin_path(struct bpf_map *map, const char *path) +static bool get_map_field_long(const char *map_name, const struct btf *btf, + const struct btf_member *m, __u64 *res) { - char buf[PATH_MAX]; - int len; + const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL); + const char *name = btf__name_by_offset(btf, m->name_off); - if (!path) - path = "/sys/fs/bpf"; + if (btf_is_ptr(t)) { + __u32 res32; + bool ret; + + ret = get_map_field_int(map_name, btf, m, &res32); + if (ret) + *res = (__u64)res32; + return ret; + } + + if (!btf_is_enum(t) && !btf_is_enum64(t)) { + pr_warn("map '%s': attr '%s': expected ENUM or ENUM64, got %s.\n", + map_name, name, btf_kind_str(t)); + return false; + } - len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map)); + if (btf_vlen(t) != 1) { + pr_warn("map '%s': attr '%s': invalid __ulong\n", + map_name, name); + return false; + } + + if (btf_is_enum(t)) { + const struct btf_enum *e = btf_enum(t); + + *res = e->val; + } else { + const struct btf_enum64 *e = btf_enum64(t); + + *res = btf_enum64_value(e); + } + return true; +} + +static int pathname_concat(char *buf, size_t buf_sz, const char *path, const char *name) +{ + int len; + + len = snprintf(buf, buf_sz, "%s/%s", path, name); if (len < 0) return -EINVAL; - else if (len >= PATH_MAX) + if (len >= buf_sz) return -ENAMETOOLONG; + return 0; +} + +static int build_map_pin_path(struct bpf_map *map, const char *path) +{ + char buf[PATH_MAX]; + int err; + + if (!path) + path = BPF_FS_DEFAULT_PATH; + + err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); + if (err) + return err; + return bpf_map__set_pin_path(map, buf); } +/* should match definition in bpf_helpers.h */ +enum libbpf_pin_type { + LIBBPF_PIN_NONE, + /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */ + LIBBPF_PIN_BY_NAME, +}; -static int parse_btf_map_def(struct bpf_object *obj, - struct bpf_map *map, - const struct btf_type *def, - bool strict, bool is_inner, - const char *pin_root_path) +int parse_btf_map_def(const char *map_name, struct btf *btf, + const struct btf_type *def_t, bool strict, + struct btf_map_def *map_def, struct btf_map_def *inner_def) { const struct btf_type *t; const struct btf_member *m; + bool is_inner = inner_def == NULL; int vlen, i; - vlen = btf_vlen(def); - m = btf_members(def); + vlen = btf_vlen(def_t); + m = btf_members(def_t); for (i = 0; i < vlen; i++, m++) { - const char *name = btf__name_by_offset(obj->btf, m->name_off); + const char *name = btf__name_by_offset(btf, m->name_off); if (!name) { - pr_warn("map '%s': invalid field #%d.\n", map->name, i); + pr_warn("map '%s': invalid field #%d.\n", map_name, i); return -EINVAL; } if (strcmp(name, "type") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, - &map->def.type)) + if (!get_map_field_int(map_name, btf, m, &map_def->map_type)) return -EINVAL; - pr_debug("map '%s': found type = %u.\n", - map->name, map->def.type); + map_def->parts |= MAP_DEF_MAP_TYPE; } else if (strcmp(name, "max_entries") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, - &map->def.max_entries)) + if (!get_map_field_int(map_name, btf, m, &map_def->max_entries)) return -EINVAL; - pr_debug("map '%s': found max_entries = %u.\n", - map->name, map->def.max_entries); + map_def->parts |= MAP_DEF_MAX_ENTRIES; } else if (strcmp(name, "map_flags") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, - &map->def.map_flags)) + if (!get_map_field_int(map_name, btf, m, &map_def->map_flags)) return -EINVAL; - pr_debug("map '%s': found map_flags = %u.\n", - map->name, map->def.map_flags); + map_def->parts |= MAP_DEF_MAP_FLAGS; } else if (strcmp(name, "numa_node") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, &map->numa_node)) + if (!get_map_field_int(map_name, btf, m, &map_def->numa_node)) return -EINVAL; - pr_debug("map '%s': found numa_node = %u.\n", map->name, map->numa_node); + map_def->parts |= MAP_DEF_NUMA_NODE; } else if (strcmp(name, "key_size") == 0) { __u32 sz; - if (!get_map_field_int(map->name, obj->btf, m, &sz)) + if (!get_map_field_int(map_name, btf, m, &sz)) return -EINVAL; - pr_debug("map '%s': found key_size = %u.\n", - map->name, sz); - if (map->def.key_size && map->def.key_size != sz) { + if (map_def->key_size && map_def->key_size != sz) { pr_warn("map '%s': conflicting key size %u != %u.\n", - map->name, map->def.key_size, sz); + map_name, map_def->key_size, sz); return -EINVAL; } - map->def.key_size = sz; + map_def->key_size = sz; + map_def->parts |= MAP_DEF_KEY_SIZE; } else if (strcmp(name, "key") == 0) { __s64 sz; - t = btf__type_by_id(obj->btf, m->type); + t = btf__type_by_id(btf, m->type); if (!t) { pr_warn("map '%s': key type [%d] not found.\n", - map->name, m->type); + map_name, m->type); return -EINVAL; } if (!btf_is_ptr(t)) { pr_warn("map '%s': key spec is not PTR: %s.\n", - map->name, btf_kind_str(t)); + map_name, btf_kind_str(t)); return -EINVAL; } - sz = btf__resolve_size(obj->btf, t->type); + sz = btf__resolve_size(btf, t->type); if (sz < 0) { pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n", - map->name, t->type, (ssize_t)sz); + map_name, t->type, (ssize_t)sz); return sz; } - pr_debug("map '%s': found key [%u], sz = %zd.\n", - map->name, t->type, (ssize_t)sz); - if (map->def.key_size && map->def.key_size != sz) { + if (map_def->key_size && map_def->key_size != sz) { pr_warn("map '%s': conflicting key size %u != %zd.\n", - map->name, map->def.key_size, (ssize_t)sz); + map_name, map_def->key_size, (ssize_t)sz); return -EINVAL; } - map->def.key_size = sz; - map->btf_key_type_id = t->type; + map_def->key_size = sz; + map_def->key_type_id = t->type; + map_def->parts |= MAP_DEF_KEY_SIZE | MAP_DEF_KEY_TYPE; } else if (strcmp(name, "value_size") == 0) { __u32 sz; - if (!get_map_field_int(map->name, obj->btf, m, &sz)) + if (!get_map_field_int(map_name, btf, m, &sz)) return -EINVAL; - pr_debug("map '%s': found value_size = %u.\n", - map->name, sz); - if (map->def.value_size && map->def.value_size != sz) { + if (map_def->value_size && map_def->value_size != sz) { pr_warn("map '%s': conflicting value size %u != %u.\n", - map->name, map->def.value_size, sz); + map_name, map_def->value_size, sz); return -EINVAL; } - map->def.value_size = sz; + map_def->value_size = sz; + map_def->parts |= MAP_DEF_VALUE_SIZE; } else if (strcmp(name, "value") == 0) { __s64 sz; - t = btf__type_by_id(obj->btf, m->type); + t = btf__type_by_id(btf, m->type); if (!t) { pr_warn("map '%s': value type [%d] not found.\n", - map->name, m->type); + map_name, m->type); return -EINVAL; } if (!btf_is_ptr(t)) { pr_warn("map '%s': value spec is not PTR: %s.\n", - map->name, btf_kind_str(t)); + map_name, btf_kind_str(t)); return -EINVAL; } - sz = btf__resolve_size(obj->btf, t->type); + sz = btf__resolve_size(btf, t->type); if (sz < 0) { pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n", - map->name, t->type, (ssize_t)sz); + map_name, t->type, (ssize_t)sz); return sz; } - pr_debug("map '%s': found value [%u], sz = %zd.\n", - map->name, t->type, (ssize_t)sz); - if (map->def.value_size && map->def.value_size != sz) { + if (map_def->value_size && map_def->value_size != sz) { pr_warn("map '%s': conflicting value size %u != %zd.\n", - map->name, map->def.value_size, (ssize_t)sz); + map_name, map_def->value_size, (ssize_t)sz); return -EINVAL; } - map->def.value_size = sz; - map->btf_value_type_id = t->type; + map_def->value_size = sz; + map_def->value_type_id = t->type; + map_def->parts |= MAP_DEF_VALUE_SIZE | MAP_DEF_VALUE_TYPE; } else if (strcmp(name, "values") == 0) { + bool is_map_in_map = bpf_map_type__is_map_in_map(map_def->map_type); + bool is_prog_array = map_def->map_type == BPF_MAP_TYPE_PROG_ARRAY; + const char *desc = is_map_in_map ? "map-in-map inner" : "prog-array value"; + char inner_map_name[128]; int err; if (is_inner) { pr_warn("map '%s': multi-level inner maps not supported.\n", - map->name); + map_name); return -ENOTSUP; } if (i != vlen - 1) { pr_warn("map '%s': '%s' member should be last.\n", - map->name, name); + map_name, name); return -EINVAL; } - if (!bpf_map_type__is_map_in_map(map->def.type)) { - pr_warn("map '%s': should be map-in-map.\n", - map->name); + if (!is_map_in_map && !is_prog_array) { + pr_warn("map '%s': should be map-in-map or prog-array.\n", + map_name); return -ENOTSUP; } - if (map->def.value_size && map->def.value_size != 4) { + if (map_def->value_size && map_def->value_size != 4) { pr_warn("map '%s': conflicting value size %u != 4.\n", - map->name, map->def.value_size); + map_name, map_def->value_size); return -EINVAL; } - map->def.value_size = 4; - t = btf__type_by_id(obj->btf, m->type); + map_def->value_size = 4; + t = btf__type_by_id(btf, m->type); if (!t) { - pr_warn("map '%s': map-in-map inner type [%d] not found.\n", - map->name, m->type); + pr_warn("map '%s': %s type [%d] not found.\n", + map_name, desc, m->type); return -EINVAL; } if (!btf_is_array(t) || btf_array(t)->nelems) { - pr_warn("map '%s': map-in-map inner spec is not a zero-sized array.\n", - map->name); + pr_warn("map '%s': %s spec is not a zero-sized array.\n", + map_name, desc); return -EINVAL; } - t = skip_mods_and_typedefs(obj->btf, btf_array(t)->type, - NULL); + t = skip_mods_and_typedefs(btf, btf_array(t)->type, NULL); if (!btf_is_ptr(t)) { - pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", - map->name, btf_kind_str(t)); + pr_warn("map '%s': %s def is of unexpected kind %s.\n", + map_name, desc, btf_kind_str(t)); return -EINVAL; } - t = skip_mods_and_typedefs(obj->btf, t->type, NULL); + t = skip_mods_and_typedefs(btf, t->type, NULL); + if (is_prog_array) { + if (!btf_is_func_proto(t)) { + pr_warn("map '%s': prog-array value def is of unexpected kind %s.\n", + map_name, btf_kind_str(t)); + return -EINVAL; + } + continue; + } if (!btf_is_struct(t)) { pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", - map->name, btf_kind_str(t)); + map_name, btf_kind_str(t)); return -EINVAL; } - map->inner_map = calloc(1, sizeof(*map->inner_map)); - if (!map->inner_map) - return -ENOMEM; - map->inner_map->sec_idx = obj->efile.btf_maps_shndx; - map->inner_map->name = malloc(strlen(map->name) + - sizeof(".inner") + 1); - if (!map->inner_map->name) - return -ENOMEM; - sprintf(map->inner_map->name, "%s.inner", map->name); - - err = parse_btf_map_def(obj, map->inner_map, t, strict, - true /* is_inner */, NULL); + snprintf(inner_map_name, sizeof(inner_map_name), "%s.inner", map_name); + err = parse_btf_map_def(inner_map_name, btf, t, strict, inner_def, NULL); if (err) return err; + + map_def->parts |= MAP_DEF_INNER_MAP; } else if (strcmp(name, "pinning") == 0) { __u32 val; - int err; if (is_inner) { - pr_debug("map '%s': inner def can't be pinned.\n", - map->name); + pr_warn("map '%s': inner def can't be pinned.\n", map_name); return -EINVAL; } - if (!get_map_field_int(map->name, obj->btf, m, &val)) + if (!get_map_field_int(map_name, btf, m, &val)) return -EINVAL; - pr_debug("map '%s': found pinning = %u.\n", - map->name, val); - - if (val != LIBBPF_PIN_NONE && - val != LIBBPF_PIN_BY_NAME) { + if (val != LIBBPF_PIN_NONE && val != LIBBPF_PIN_BY_NAME) { pr_warn("map '%s': invalid pinning value %u.\n", - map->name, val); + map_name, val); return -EINVAL; } - if (val == LIBBPF_PIN_BY_NAME) { - err = build_map_pin_path(map, pin_root_path); - if (err) { - pr_warn("map '%s': couldn't build pin path.\n", - map->name); - return err; - } - } + map_def->pinning = val; + map_def->parts |= MAP_DEF_PINNING; + } else if (strcmp(name, "map_extra") == 0) { + __u64 map_extra; + + if (!get_map_field_long(map_name, btf, m, &map_extra)) + return -EINVAL; + map_def->map_extra = map_extra; + map_def->parts |= MAP_DEF_MAP_EXTRA; } else { if (strict) { - pr_warn("map '%s': unknown field '%s'.\n", - map->name, name); + pr_warn("map '%s': unknown field '%s'.\n", map_name, name); return -ENOTSUP; } - pr_debug("map '%s': ignoring unknown field '%s'.\n", - map->name, name); + pr_debug("map '%s': ignoring unknown field '%s'.\n", map_name, name); } } - if (map->def.type == BPF_MAP_TYPE_UNSPEC) { - pr_warn("map '%s': map type isn't specified.\n", map->name); + if (map_def->map_type == BPF_MAP_TYPE_UNSPEC) { + pr_warn("map '%s': map type isn't specified.\n", map_name); return -EINVAL; } return 0; } +static size_t adjust_ringbuf_sz(size_t sz) +{ + __u32 page_sz = sysconf(_SC_PAGE_SIZE); + __u32 mul; + + /* if user forgot to set any size, make sure they see error */ + if (sz == 0) + return 0; + /* Kernel expects BPF_MAP_TYPE_RINGBUF's max_entries to be + * a power-of-2 multiple of kernel's page size. If user diligently + * satisified these conditions, pass the size through. + */ + if ((sz % page_sz) == 0 && is_pow_of_2(sz / page_sz)) + return sz; + + /* Otherwise find closest (page_sz * power_of_2) product bigger than + * user-set size to satisfy both user size request and kernel + * requirements and substitute correct max_entries for map creation. + */ + for (mul = 1; mul <= UINT_MAX / page_sz; mul <<= 1) { + if (mul * page_sz > sz) + return mul * page_sz; + } + + /* if it's impossible to satisfy the conditions (i.e., user size is + * very close to UINT_MAX but is not a power-of-2 multiple of + * page_size) then just return original size and let kernel reject it + */ + return sz; +} + +static bool map_is_ringbuf(const struct bpf_map *map) +{ + return map->def.type == BPF_MAP_TYPE_RINGBUF || + map->def.type == BPF_MAP_TYPE_USER_RINGBUF; +} + +static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def) +{ + map->def.type = def->map_type; + map->def.key_size = def->key_size; + map->def.value_size = def->value_size; + map->def.max_entries = def->max_entries; + map->def.map_flags = def->map_flags; + map->map_extra = def->map_extra; + + map->numa_node = def->numa_node; + map->btf_key_type_id = def->key_type_id; + map->btf_value_type_id = def->value_type_id; + + /* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */ + if (map_is_ringbuf(map)) + map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); + + if (def->parts & MAP_DEF_MAP_TYPE) + pr_debug("map '%s': found type = %u.\n", map->name, def->map_type); + + if (def->parts & MAP_DEF_KEY_TYPE) + pr_debug("map '%s': found key [%u], sz = %u.\n", + map->name, def->key_type_id, def->key_size); + else if (def->parts & MAP_DEF_KEY_SIZE) + pr_debug("map '%s': found key_size = %u.\n", map->name, def->key_size); + + if (def->parts & MAP_DEF_VALUE_TYPE) + pr_debug("map '%s': found value [%u], sz = %u.\n", + map->name, def->value_type_id, def->value_size); + else if (def->parts & MAP_DEF_VALUE_SIZE) + pr_debug("map '%s': found value_size = %u.\n", map->name, def->value_size); + + if (def->parts & MAP_DEF_MAX_ENTRIES) + pr_debug("map '%s': found max_entries = %u.\n", map->name, def->max_entries); + if (def->parts & MAP_DEF_MAP_FLAGS) + pr_debug("map '%s': found map_flags = 0x%x.\n", map->name, def->map_flags); + if (def->parts & MAP_DEF_MAP_EXTRA) + pr_debug("map '%s': found map_extra = 0x%llx.\n", map->name, + (unsigned long long)def->map_extra); + if (def->parts & MAP_DEF_PINNING) + pr_debug("map '%s': found pinning = %u.\n", map->name, def->pinning); + if (def->parts & MAP_DEF_NUMA_NODE) + pr_debug("map '%s': found numa_node = %u.\n", map->name, def->numa_node); + + if (def->parts & MAP_DEF_INNER_MAP) + pr_debug("map '%s': found inner map definition.\n", map->name); +} + +static const char *btf_var_linkage_str(__u32 linkage) +{ + switch (linkage) { + case BTF_VAR_STATIC: return "static"; + case BTF_VAR_GLOBAL_ALLOCATED: return "global"; + case BTF_VAR_GLOBAL_EXTERN: return "extern"; + default: return "unknown"; + } +} + static int bpf_object__init_user_btf_map(struct bpf_object *obj, const struct btf_type *sec, int var_idx, int sec_idx, const Elf_Data *data, bool strict, const char *pin_root_path) { + struct btf_map_def map_def = {}, inner_def = {}; const struct btf_type *var, *def; const struct btf_var_secinfo *vi; const struct btf_var *var_extra; const char *map_name; struct bpf_map *map; + int err; vi = btf_var_secinfos(sec) + var_idx; var = btf__type_by_id(obj->btf, vi->type); @@ -2250,10 +2781,9 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj, map_name, btf_kind_str(var)); return -EINVAL; } - if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED && - var_extra->linkage != BTF_VAR_STATIC) { - pr_warn("map '%s': unsupported var linkage %u.\n", - map_name, var_extra->linkage); + if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED) { + pr_warn("map '%s': unsupported map linkage %s.\n", + map_name, btf_var_linkage_str(var_extra->linkage)); return -EOPNOTSUPP; } @@ -2284,7 +2814,67 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj, pr_debug("map '%s': at sec_idx %d, offset %zu.\n", map_name, map->sec_idx, map->sec_offset); - return parse_btf_map_def(obj, map, def, strict, false, pin_root_path); + err = parse_btf_map_def(map->name, obj->btf, def, strict, &map_def, &inner_def); + if (err) + return err; + + fill_map_from_def(map, &map_def); + + if (map_def.pinning == LIBBPF_PIN_BY_NAME) { + err = build_map_pin_path(map, pin_root_path); + if (err) { + pr_warn("map '%s': couldn't build pin path.\n", map->name); + return err; + } + } + + if (map_def.parts & MAP_DEF_INNER_MAP) { + map->inner_map = calloc(1, sizeof(*map->inner_map)); + if (!map->inner_map) + return -ENOMEM; + map->inner_map->fd = create_placeholder_fd(); + if (map->inner_map->fd < 0) + return map->inner_map->fd; + map->inner_map->sec_idx = sec_idx; + map->inner_map->name = malloc(strlen(map_name) + sizeof(".inner") + 1); + if (!map->inner_map->name) + return -ENOMEM; + sprintf(map->inner_map->name, "%s.inner", map_name); + + fill_map_from_def(map->inner_map, &inner_def); + } + + err = map_fill_btf_type_info(obj, map); + if (err) + return err; + + return 0; +} + +static int init_arena_map_data(struct bpf_object *obj, struct bpf_map *map, + const char *sec_name, int sec_idx, + void *data, size_t data_sz) +{ + const long page_sz = sysconf(_SC_PAGE_SIZE); + size_t mmap_sz; + + mmap_sz = bpf_map_mmap_sz(obj->arena_map); + if (roundup(data_sz, page_sz) > mmap_sz) { + pr_warn("elf: sec '%s': declared ARENA map size (%zu) is too small to hold global __arena variables of size %zu\n", + sec_name, mmap_sz, data_sz); + return -E2BIG; + } + + obj->arena_data = malloc(data_sz); + if (!obj->arena_data) + return -ENOMEM; + memcpy(obj->arena_data, data, data_sz); + obj->arena_data_sz = data_sz; + + /* make bpf_map__init_value() work for ARENA maps */ + map->mmaped = obj->arena_data; + + return 0; } static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, @@ -2308,8 +2898,8 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, return -EINVAL; } - nr_types = btf__get_nr_types(obj->btf); - for (i = 1; i <= nr_types; i++) { + nr_types = btf__type_cnt(obj->btf); + for (i = 1; i < nr_types; i++) { t = btf__type_by_id(obj->btf, i); if (!btf_is_datasec(t)) continue; @@ -2336,6 +2926,33 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, return err; } + for (i = 0; i < obj->nr_maps; i++) { + struct bpf_map *map = &obj->maps[i]; + + if (map->def.type != BPF_MAP_TYPE_ARENA) + continue; + + if (obj->arena_map) { + pr_warn("map '%s': only single ARENA map is supported (map '%s' is also ARENA)\n", + map->name, obj->arena_map->name); + return -EINVAL; + } + obj->arena_map = map; + + if (obj->efile.arena_data) { + err = init_arena_map_data(obj, map, ARENA_SEC, obj->efile.arena_data_shndx, + obj->efile.arena_data->d_buf, + obj->efile.arena_data->d_size); + if (err) + return err; + } + } + if (obj->efile.arena_data && !obj->arena_map) { + pr_warn("elf: sec '%s': to use global __arena variables the ARENA map should be explicitly declared in SEC(\".maps\")\n", + ARENA_SEC); + return -ENOENT; + } + return 0; } @@ -2344,54 +2961,69 @@ static int bpf_object__init_maps(struct bpf_object *obj, { const char *pin_root_path; bool strict; - int err; + int err = 0; strict = !OPTS_GET(opts, relaxed_maps, false); pin_root_path = OPTS_GET(opts, pin_root_path, NULL); - err = bpf_object__init_user_maps(obj, strict); - err = err ?: bpf_object__init_user_btf_maps(obj, strict, pin_root_path); + err = bpf_object__init_user_btf_maps(obj, strict, pin_root_path); err = err ?: bpf_object__init_global_data_maps(obj); err = err ?: bpf_object__init_kconfig_map(obj); - err = err ?: bpf_object__init_struct_ops_maps(obj); - if (err) - return err; + err = err ?: bpf_object_init_struct_ops(obj); - return 0; + return err; } static bool section_have_execinstr(struct bpf_object *obj, int idx) { - GElf_Shdr sh; + Elf64_Shdr *sh; - if (elf_sec_hdr(obj, elf_sec_by_idx(obj, idx), &sh)) + sh = elf_sec_hdr(obj, elf_sec_by_idx(obj, idx)); + if (!sh) return false; - return sh.sh_flags & SHF_EXECINSTR; + return sh->sh_flags & SHF_EXECINSTR; } -static bool btf_needs_sanitization(struct bpf_object *obj) +static bool starts_with_qmark(const char *s) { - bool has_func_global = kernel_supports(FEAT_BTF_GLOBAL_FUNC); - bool has_datasec = kernel_supports(FEAT_BTF_DATASEC); - bool has_func = kernel_supports(FEAT_BTF_FUNC); - - return !has_func || !has_datasec || !has_func_global; + return s && s[0] == '?'; } -static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) +static bool btf_needs_sanitization(struct bpf_object *obj) { - bool has_func_global = kernel_supports(FEAT_BTF_GLOBAL_FUNC); - bool has_datasec = kernel_supports(FEAT_BTF_DATASEC); - bool has_func = kernel_supports(FEAT_BTF_FUNC); + bool has_func_global = kernel_supports(obj, FEAT_BTF_GLOBAL_FUNC); + bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC); + bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT); + bool has_func = kernel_supports(obj, FEAT_BTF_FUNC); + bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG); + bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG); + bool has_enum64 = kernel_supports(obj, FEAT_BTF_ENUM64); + bool has_qmark_datasec = kernel_supports(obj, FEAT_BTF_QMARK_DATASEC); + + return !has_func || !has_datasec || !has_func_global || !has_float || + !has_decl_tag || !has_type_tag || !has_enum64 || !has_qmark_datasec; +} + +static int bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) +{ + bool has_func_global = kernel_supports(obj, FEAT_BTF_GLOBAL_FUNC); + bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC); + bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT); + bool has_func = kernel_supports(obj, FEAT_BTF_FUNC); + bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG); + bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG); + bool has_enum64 = kernel_supports(obj, FEAT_BTF_ENUM64); + bool has_qmark_datasec = kernel_supports(obj, FEAT_BTF_QMARK_DATASEC); + int enum64_placeholder_id = 0; struct btf_type *t; int i, j, vlen; - for (i = 1; i <= btf__get_nr_types(btf); i++) { + for (i = 1; i < btf__type_cnt(btf); i++) { t = (struct btf_type *)btf__type_by_id(btf, i); - if (!has_datasec && btf_is_var(t)) { - /* replace VAR with INT */ + if ((!has_datasec && btf_is_var(t)) || (!has_decl_tag && btf_is_decl_tag(t))) { + /* replace VAR/DECL_TAG with INT */ t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0); /* * using size = 1 is the safest choice, 4 will be too @@ -2409,7 +3041,7 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) name = (char *)btf__name_by_offset(btf, t->name_off); while (*name) { - if (*name == '.') + if (*name == '.' || *name == '?') *name = '_'; name++; } @@ -2424,6 +3056,14 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) vt = (void *)btf__type_by_id(btf, v->type); m->name_off = vt->name_off; } + } else if (!has_qmark_datasec && btf_is_datasec(t) && + starts_with_qmark(btf__name_by_offset(btf, t->name_off))) { + /* replace '?' prefix with '_' for DATASEC names */ + char *name; + + name = (char *)btf__name_by_offset(btf, t->name_off); + if (name[0] == '?') + name[0] = '_'; } else if (!has_func && btf_is_func_proto(t)) { /* replace FUNC_PROTO with ENUM */ vlen = btf_vlen(t); @@ -2435,20 +3075,55 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) } else if (!has_func_global && btf_is_func(t)) { /* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */ t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0); + } else if (!has_float && btf_is_float(t)) { + /* replace FLOAT with an equally-sized empty STRUCT; + * since C compilers do not accept e.g. "float" as a + * valid struct name, make it anonymous + */ + t->name_off = 0; + t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 0); + } else if (!has_type_tag && btf_is_type_tag(t)) { + /* replace TYPE_TAG with a CONST */ + t->name_off = 0; + t->info = BTF_INFO_ENC(BTF_KIND_CONST, 0, 0); + } else if (!has_enum64 && btf_is_enum(t)) { + /* clear the kflag */ + t->info = btf_type_info(btf_kind(t), btf_vlen(t), false); + } else if (!has_enum64 && btf_is_enum64(t)) { + /* replace ENUM64 with a union */ + struct btf_member *m; + + if (enum64_placeholder_id == 0) { + enum64_placeholder_id = btf__add_int(btf, "enum64_placeholder", 1, 0); + if (enum64_placeholder_id < 0) + return enum64_placeholder_id; + + t = (struct btf_type *)btf__type_by_id(btf, i); + } + + m = btf_members(t); + vlen = btf_vlen(t); + t->info = BTF_INFO_ENC(BTF_KIND_UNION, 0, vlen); + for (j = 0; j < vlen; j++, m++) { + m->type = enum64_placeholder_id; + m->offset = 0; + } } } + + return 0; } static bool libbpf_needs_btf(const struct bpf_object *obj) { return obj->efile.btf_maps_shndx >= 0 || - obj->efile.st_ops_shndx >= 0 || + obj->efile.has_st_ops || obj->nr_extern > 0; } static bool kernel_needs_btf(const struct bpf_object *obj) { - return obj->efile.st_ops_shndx >= 0; + return obj->efile.has_st_ops; } static int bpf_object__init_btf(struct bpf_object *obj, @@ -2459,31 +3134,69 @@ static int bpf_object__init_btf(struct bpf_object *obj, if (btf_data) { obj->btf = btf__new(btf_data->d_buf, btf_data->d_size); - if (IS_ERR(obj->btf)) { - err = PTR_ERR(obj->btf); + err = libbpf_get_error(obj->btf); + if (err) { obj->btf = NULL; - pr_warn("Error loading ELF section %s: %d.\n", - BTF_ELF_SEC, err); + pr_warn("Error loading ELF section %s: %d.\n", BTF_ELF_SEC, err); goto out; } /* enforce 8-byte pointers for BPF-targeted BTFs */ btf__set_pointer_size(obj->btf, 8); - err = 0; } if (btf_ext_data) { + struct btf_ext_info *ext_segs[3]; + int seg_num, sec_num; + if (!obj->btf) { pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n", BTF_EXT_ELF_SEC, BTF_ELF_SEC); goto out; } - obj->btf_ext = btf_ext__new(btf_ext_data->d_buf, - btf_ext_data->d_size); - if (IS_ERR(obj->btf_ext)) { - pr_warn("Error loading ELF section %s: %ld. Ignored and continue.\n", - BTF_EXT_ELF_SEC, PTR_ERR(obj->btf_ext)); + obj->btf_ext = btf_ext__new(btf_ext_data->d_buf, btf_ext_data->d_size); + err = libbpf_get_error(obj->btf_ext); + if (err) { + pr_warn("Error loading ELF section %s: %d. Ignored and continue.\n", + BTF_EXT_ELF_SEC, err); obj->btf_ext = NULL; goto out; } + + /* setup .BTF.ext to ELF section mapping */ + ext_segs[0] = &obj->btf_ext->func_info; + ext_segs[1] = &obj->btf_ext->line_info; + ext_segs[2] = &obj->btf_ext->core_relo_info; + for (seg_num = 0; seg_num < ARRAY_SIZE(ext_segs); seg_num++) { + struct btf_ext_info *seg = ext_segs[seg_num]; + const struct btf_ext_info_sec *sec; + const char *sec_name; + Elf_Scn *scn; + + if (seg->sec_cnt == 0) + continue; + + seg->sec_idxs = calloc(seg->sec_cnt, sizeof(*seg->sec_idxs)); + if (!seg->sec_idxs) { + err = -ENOMEM; + goto out; + } + + sec_num = 0; + for_each_btf_ext_sec(seg, sec) { + /* preventively increment index to avoid doing + * this before every continue below + */ + sec_num++; + + sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); + if (str_is_empty(sec_name)) + continue; + scn = elf_sec_by_name(obj, sec_name); + if (!scn) + continue; + + seg->sec_idxs[sec_num - 1] = elf_ndxscn(scn); + } + } } out: if (err && libbpf_needs_btf(obj)) { @@ -2493,23 +3206,134 @@ out: return 0; } -static int bpf_object__finalize_btf(struct bpf_object *obj) +static int compare_vsi_off(const void *_a, const void *_b) { + const struct btf_var_secinfo *a = _a; + const struct btf_var_secinfo *b = _b; + + return a->offset - b->offset; +} + +static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf, + struct btf_type *t) +{ + __u32 size = 0, i, vars = btf_vlen(t); + const char *sec_name = btf__name_by_offset(btf, t->name_off); + struct btf_var_secinfo *vsi; + bool fixup_offsets = false; int err; + if (!sec_name) { + pr_debug("No name found in string section for DATASEC kind.\n"); + return -ENOENT; + } + + /* Extern-backing datasecs (.ksyms, .kconfig) have their size and + * variable offsets set at the previous step. Further, not every + * extern BTF VAR has corresponding ELF symbol preserved, so we skip + * all fixups altogether for such sections and go straight to sorting + * VARs within their DATASEC. + */ + if (strcmp(sec_name, KCONFIG_SEC) == 0 || strcmp(sec_name, KSYMS_SEC) == 0) + goto sort_vars; + + /* Clang leaves DATASEC size and VAR offsets as zeroes, so we need to + * fix this up. But BPF static linker already fixes this up and fills + * all the sizes and offsets during static linking. So this step has + * to be optional. But the STV_HIDDEN handling is non-optional for any + * non-extern DATASEC, so the variable fixup loop below handles both + * functions at the same time, paying the cost of BTF VAR <-> ELF + * symbol matching just once. + */ + if (t->size == 0) { + err = find_elf_sec_sz(obj, sec_name, &size); + if (err || !size) { + pr_debug("sec '%s': failed to determine size from ELF: size %u, err %d\n", + sec_name, size, err); + return -ENOENT; + } + + t->size = size; + fixup_offsets = true; + } + + for (i = 0, vsi = btf_var_secinfos(t); i < vars; i++, vsi++) { + const struct btf_type *t_var; + struct btf_var *var; + const char *var_name; + Elf64_Sym *sym; + + t_var = btf__type_by_id(btf, vsi->type); + if (!t_var || !btf_is_var(t_var)) { + pr_debug("sec '%s': unexpected non-VAR type found\n", sec_name); + return -EINVAL; + } + + var = btf_var(t_var); + if (var->linkage == BTF_VAR_STATIC || var->linkage == BTF_VAR_GLOBAL_EXTERN) + continue; + + var_name = btf__name_by_offset(btf, t_var->name_off); + if (!var_name) { + pr_debug("sec '%s': failed to find name of DATASEC's member #%d\n", + sec_name, i); + return -ENOENT; + } + + sym = find_elf_var_sym(obj, var_name); + if (IS_ERR(sym)) { + pr_debug("sec '%s': failed to find ELF symbol for VAR '%s'\n", + sec_name, var_name); + return -ENOENT; + } + + if (fixup_offsets) + vsi->offset = sym->st_value; + + /* if variable is a global/weak symbol, but has restricted + * (STV_HIDDEN or STV_INTERNAL) visibility, mark its BTF VAR + * as static. This follows similar logic for functions (BPF + * subprogs) and influences libbpf's further decisions about + * whether to make global data BPF array maps as + * BPF_F_MMAPABLE. + */ + if (ELF64_ST_VISIBILITY(sym->st_other) == STV_HIDDEN + || ELF64_ST_VISIBILITY(sym->st_other) == STV_INTERNAL) + var->linkage = BTF_VAR_STATIC; + } + +sort_vars: + qsort(btf_var_secinfos(t), vars, sizeof(*vsi), compare_vsi_off); + return 0; +} + +static int bpf_object_fixup_btf(struct bpf_object *obj) +{ + int i, n, err = 0; + if (!obj->btf) return 0; - err = btf__finalize_data(obj, obj->btf); - if (err) { - pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err); - return err; + n = btf__type_cnt(obj->btf); + for (i = 1; i < n; i++) { + struct btf_type *t = btf_type_by_id(obj->btf, i); + + /* Loader needs to fix up some of the things compiler + * couldn't get its hands on while emitting BTF. This + * is section size and global variable offset. We use + * the info from the ELF itself for this purpose. + */ + if (btf_is_datasec(t)) { + err = btf_fixup_datasec(obj, obj->btf, t); + if (err) + return err; + } } return 0; } -static inline bool libbpf_prog_needs_vmlinux_btf(struct bpf_program *prog) +static bool prog_needs_vmlinux_btf(struct bpf_program *prog) { if (prog->type == BPF_PROG_TYPE_STRUCT_OPS || prog->type == BPF_PROG_TYPE_LSM) @@ -2524,42 +3348,61 @@ static inline bool libbpf_prog_needs_vmlinux_btf(struct bpf_program *prog) return false; } -static int bpf_object__load_vmlinux_btf(struct bpf_object *obj) +static bool map_needs_vmlinux_btf(struct bpf_map *map) +{ + return bpf_map__is_struct_ops(map); +} + +static bool obj_needs_vmlinux_btf(const struct bpf_object *obj) { - bool need_vmlinux_btf = false; struct bpf_program *prog; - int i, err; + struct bpf_map *map; + int i; - /* CO-RE relocations need kernel BTF */ - if (obj->btf_ext && obj->btf_ext->core_relo_info.len) - need_vmlinux_btf = true; + /* CO-RE relocations need kernel BTF, only when btf_custom_path + * is not specified + */ + if (obj->btf_ext && obj->btf_ext->core_relo_info.len && !obj->btf_custom_path) + return true; /* Support for typed ksyms needs kernel BTF */ for (i = 0; i < obj->nr_extern; i++) { const struct extern_desc *ext; ext = &obj->externs[i]; - if (ext->type == EXT_KSYM && ext->ksym.type_id) { - need_vmlinux_btf = true; - break; - } + if (ext->type == EXT_KSYM && ext->ksym.type_id) + return true; } bpf_object__for_each_program(prog, obj) { - if (!prog->load) + if (!prog->autoload) continue; - if (libbpf_prog_needs_vmlinux_btf(prog)) { - need_vmlinux_btf = true; - break; - } + if (prog_needs_vmlinux_btf(prog)) + return true; } - if (!need_vmlinux_btf) + bpf_object__for_each_map(map, obj) { + if (map_needs_vmlinux_btf(map)) + return true; + } + + return false; +} + +static int bpf_object__load_vmlinux_btf(struct bpf_object *obj, bool force) +{ + int err; + + /* btf_vmlinux could be loaded earlier */ + if (obj->btf_vmlinux || obj->gen_loader) return 0; - obj->btf_vmlinux = libbpf_find_kernel_btf(); - if (IS_ERR(obj->btf_vmlinux)) { - err = PTR_ERR(obj->btf_vmlinux); + if (!force && !obj_needs_vmlinux_btf(obj)) + return 0; + + obj->btf_vmlinux = btf__load_vmlinux_btf(); + err = libbpf_get_error(obj->btf_vmlinux); + if (err) { pr_warn("Error loading vmlinux BTF: %d\n", err); obj->btf_vmlinux = NULL; return err; @@ -2571,12 +3414,12 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) { struct btf *kern_btf = obj->btf; bool btf_mandatory, sanitize; - int err = 0; + int i, err = 0; if (!obj->btf) return 0; - if (!kernel_supports(FEAT_BTF)) { + if (!kernel_supports(obj, FEAT_BTF)) { if (kernel_needs_btf(obj)) { err = -EOPNOTSUPP; goto report; @@ -2585,23 +3428,73 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) return 0; } + /* Even though some subprogs are global/weak, user might prefer more + * permissive BPF verification process that BPF verifier performs for + * static functions, taking into account more context from the caller + * functions. In such case, they need to mark such subprogs with + * __attribute__((visibility("hidden"))) and libbpf will adjust + * corresponding FUNC BTF type to be marked as static and trigger more + * involved BPF verification process. + */ + for (i = 0; i < obj->nr_programs; i++) { + struct bpf_program *prog = &obj->programs[i]; + struct btf_type *t; + const char *name; + int j, n; + + if (!prog->mark_btf_static || !prog_is_subprog(obj, prog)) + continue; + + n = btf__type_cnt(obj->btf); + for (j = 1; j < n; j++) { + t = btf_type_by_id(obj->btf, j); + if (!btf_is_func(t) || btf_func_linkage(t) != BTF_FUNC_GLOBAL) + continue; + + name = btf__str_by_offset(obj->btf, t->name_off); + if (strcmp(name, prog->name) != 0) + continue; + + t->info = btf_type_info(BTF_KIND_FUNC, BTF_FUNC_STATIC, 0); + break; + } + } + sanitize = btf_needs_sanitization(obj); if (sanitize) { const void *raw_data; __u32 sz; /* clone BTF to sanitize a copy and leave the original intact */ - raw_data = btf__get_raw_data(obj->btf, &sz); + raw_data = btf__raw_data(obj->btf, &sz); kern_btf = btf__new(raw_data, sz); - if (IS_ERR(kern_btf)) - return PTR_ERR(kern_btf); + err = libbpf_get_error(kern_btf); + if (err) + return err; /* enforce 8-byte pointers for BPF-targeted BTFs */ btf__set_pointer_size(obj->btf, 8); - bpf_object__sanitize_btf(obj, kern_btf); + err = bpf_object__sanitize_btf(obj, kern_btf); + if (err) + return err; } - err = btf__load(kern_btf); + if (obj->gen_loader) { + __u32 raw_size = 0; + const void *raw_data = btf__raw_data(kern_btf, &raw_size); + + if (!raw_data) + return -ENOMEM; + bpf_gen__load_btf(obj->gen_loader, raw_data, raw_size); + /* Pretend to have valid FD to pass various fd >= 0 checks. + * This fd == 0 will not be used with any syscall and will be reset to -1 eventually. + */ + btf__set_fd(kern_btf, 0); + } else { + /* currently BPF_BTF_LOAD only supports log_level 1 */ + err = btf_load_into_kernel(kern_btf, obj->log_buf, obj->log_size, + obj->log_level ? 1 : 0, obj->token_fd); + } if (sanitize) { if (!err) { /* move fd to libbpf's BTF */ @@ -2682,32 +3575,36 @@ static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name) return NULL; } -static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr) +static Elf64_Shdr *elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn) { + Elf64_Shdr *shdr; + if (!scn) - return -EINVAL; + return NULL; - if (gelf_getshdr(scn, hdr) != hdr) { + shdr = elf64_getshdr(scn); + if (!shdr) { pr_warn("elf: failed to get section(%zu) header from %s: %s\n", elf_ndxscn(scn), obj->path, elf_errmsg(-1)); - return -EINVAL; + return NULL; } - return 0; + return shdr; } static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn) { const char *name; - GElf_Shdr sh; + Elf64_Shdr *sh; if (!scn) return NULL; - if (elf_sec_hdr(obj, scn, &sh)) + sh = elf_sec_hdr(obj, scn); + if (!sh) return NULL; - name = elf_sec_str(obj, sh.sh_name); + name = elf_sec_str(obj, sh->sh_name); if (!name) { pr_warn("elf: failed to get section(%zu) name from %s: %s\n", elf_ndxscn(scn), obj->path, elf_errmsg(-1)); @@ -2735,40 +3632,36 @@ static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn) return data; } -static int elf_sym_by_sec_off(const struct bpf_object *obj, size_t sec_idx, - size_t off, __u32 sym_type, GElf_Sym *sym) +static Elf64_Sym *elf_sym_by_idx(const struct bpf_object *obj, size_t idx) { - Elf_Data *symbols = obj->efile.symbols; - size_t n = symbols->d_size / sizeof(GElf_Sym); - int i; + if (idx >= obj->efile.symbols->d_size / sizeof(Elf64_Sym)) + return NULL; - for (i = 0; i < n; i++) { - if (!gelf_getsym(symbols, i, sym)) - continue; - if (sym->st_shndx != sec_idx || sym->st_value != off) - continue; - if (GELF_ST_TYPE(sym->st_info) != sym_type) - continue; - return 0; - } + return (Elf64_Sym *)obj->efile.symbols->d_buf + idx; +} - return -ENOENT; +static Elf64_Rel *elf_rel_by_idx(Elf_Data *data, size_t idx) +{ + if (idx >= data->d_size / sizeof(Elf64_Rel)) + return NULL; + + return (Elf64_Rel *)data->d_buf + idx; } static bool is_sec_name_dwarf(const char *name) { /* approximation, but the actual list is too long */ - return strncmp(name, ".debug_", sizeof(".debug_") - 1) == 0; + return str_has_pfx(name, ".debug_"); } -static bool ignore_elf_section(GElf_Shdr *hdr, const char *name) +static bool ignore_elf_section(Elf64_Shdr *hdr, const char *name) { /* no special handling of .strtab */ if (hdr->sh_type == SHT_STRTAB) return true; /* ignore .llvm_addrsig section as well */ - if (hdr->sh_type == 0x6FFF4C03 /* SHT_LLVM_ADDRSIG */) + if (hdr->sh_type == SHT_LLVM_ADDRSIG) return true; /* no subprograms will lead to an empty .text section, ignore it */ @@ -2780,7 +3673,7 @@ static bool ignore_elf_section(GElf_Shdr *hdr, const char *name) if (is_sec_name_dwarf(name)) return true; - if (strncmp(name, ".rel", sizeof(".rel") - 1) == 0) { + if (str_has_pfx(name, ".rel")) { name += sizeof(".rel") - 1; /* DWARF section relocations */ if (is_sec_name_dwarf(name)) @@ -2809,6 +3702,7 @@ static int cmp_progs(const void *_a, const void *_b) static int bpf_object__elf_collect(struct bpf_object *obj) { + struct elf_sec_desc *sec_desc; Elf *elf = obj->efile.elf; Elf_Data *btf_ext_data = NULL; Elf_Data *btf_data = NULL; @@ -2816,17 +3710,32 @@ static int bpf_object__elf_collect(struct bpf_object *obj) const char *name; Elf_Data *data; Elf_Scn *scn; - GElf_Shdr sh; + Elf64_Shdr *sh; + + /* ELF section indices are 0-based, but sec #0 is special "invalid" + * section. Since section count retrieved by elf_getshdrnum() does + * include sec #0, it is already the necessary size of an array to keep + * all the sections. + */ + if (elf_getshdrnum(obj->efile.elf, &obj->efile.sec_cnt)) { + pr_warn("elf: failed to get the number of sections for %s: %s\n", + obj->path, elf_errmsg(-1)); + return -LIBBPF_ERRNO__FORMAT; + } + obj->efile.secs = calloc(obj->efile.sec_cnt, sizeof(*obj->efile.secs)); + if (!obj->efile.secs) + return -ENOMEM; /* a bunch of ELF parsing functionality depends on processing symbols, * so do the first pass and find the symbol table */ scn = NULL; while ((scn = elf_nextscn(elf, scn)) != NULL) { - if (elf_sec_hdr(obj, scn, &sh)) + sh = elf_sec_hdr(obj, scn); + if (!sh) return -LIBBPF_ERRNO__FORMAT; - if (sh.sh_type == SHT_SYMTAB) { + if (sh->sh_type == SHT_SYMTAB) { if (obj->efile.symbols) { pr_warn("elf: multiple symbol tables in %s\n", obj->path); return -LIBBPF_ERRNO__FORMAT; @@ -2836,24 +3745,34 @@ static int bpf_object__elf_collect(struct bpf_object *obj) if (!data) return -LIBBPF_ERRNO__FORMAT; + idx = elf_ndxscn(scn); + obj->efile.symbols = data; - obj->efile.symbols_shndx = elf_ndxscn(scn); - obj->efile.strtabidx = sh.sh_link; + obj->efile.symbols_shndx = idx; + obj->efile.strtabidx = sh->sh_link; } } + if (!obj->efile.symbols) { + pr_warn("elf: couldn't find symbol table in %s, stripped object file?\n", + obj->path); + return -ENOENT; + } + scn = NULL; while ((scn = elf_nextscn(elf, scn)) != NULL) { - idx++; + idx = elf_ndxscn(scn); + sec_desc = &obj->efile.secs[idx]; - if (elf_sec_hdr(obj, scn, &sh)) + sh = elf_sec_hdr(obj, scn); + if (!sh) return -LIBBPF_ERRNO__FORMAT; - name = elf_sec_str(obj, sh.sh_name); + name = elf_sec_str(obj, sh->sh_name); if (!name) return -LIBBPF_ERRNO__FORMAT; - if (ignore_elf_section(&sh, name)) + if (ignore_elf_section(sh, name)) continue; data = elf_sec_data(obj, scn); @@ -2862,8 +3781,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj) pr_debug("elf: section(%d) %s, size %ld, link %d, flags %lx, type=%d\n", idx, name, (unsigned long)data->d_size, - (int)sh.sh_link, (unsigned long)sh.sh_flags, - (int)sh.sh_type); + (int)sh->sh_link, (unsigned long)sh->sh_flags, + (int)sh->sh_type); if (strcmp(name, "license") == 0) { err = bpf_object__init_license(obj, data->d_buf, data->d_size); @@ -2874,66 +3793,83 @@ static int bpf_object__elf_collect(struct bpf_object *obj) if (err) return err; } else if (strcmp(name, "maps") == 0) { - obj->efile.maps_shndx = idx; + pr_warn("elf: legacy map definitions in 'maps' section are not supported by libbpf v1.0+\n"); + return -ENOTSUP; } else if (strcmp(name, MAPS_ELF_SEC) == 0) { obj->efile.btf_maps_shndx = idx; } else if (strcmp(name, BTF_ELF_SEC) == 0) { + if (sh->sh_type != SHT_PROGBITS) + return -LIBBPF_ERRNO__FORMAT; btf_data = data; } else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) { + if (sh->sh_type != SHT_PROGBITS) + return -LIBBPF_ERRNO__FORMAT; btf_ext_data = data; - } else if (sh.sh_type == SHT_SYMTAB) { + } else if (sh->sh_type == SHT_SYMTAB) { /* already processed during the first pass above */ - } else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) { - if (sh.sh_flags & SHF_EXECINSTR) { + } else if (sh->sh_type == SHT_PROGBITS && data->d_size > 0) { + if (sh->sh_flags & SHF_EXECINSTR) { if (strcmp(name, ".text") == 0) obj->efile.text_shndx = idx; err = bpf_object__add_programs(obj, data, name, idx); if (err) return err; - } else if (strcmp(name, DATA_SEC) == 0) { - obj->efile.data = data; - obj->efile.data_shndx = idx; - } else if (strcmp(name, RODATA_SEC) == 0) { - obj->efile.rodata = data; - obj->efile.rodata_shndx = idx; - } else if (strcmp(name, STRUCT_OPS_SEC) == 0) { - obj->efile.st_ops_data = data; - obj->efile.st_ops_shndx = idx; + } else if (strcmp(name, DATA_SEC) == 0 || + str_has_pfx(name, DATA_SEC ".")) { + sec_desc->sec_type = SEC_DATA; + sec_desc->shdr = sh; + sec_desc->data = data; + } else if (strcmp(name, RODATA_SEC) == 0 || + str_has_pfx(name, RODATA_SEC ".")) { + sec_desc->sec_type = SEC_RODATA; + sec_desc->shdr = sh; + sec_desc->data = data; + } else if (strcmp(name, STRUCT_OPS_SEC) == 0 || + strcmp(name, STRUCT_OPS_LINK_SEC) == 0 || + strcmp(name, "?" STRUCT_OPS_SEC) == 0 || + strcmp(name, "?" STRUCT_OPS_LINK_SEC) == 0) { + sec_desc->sec_type = SEC_ST_OPS; + sec_desc->shdr = sh; + sec_desc->data = data; + obj->efile.has_st_ops = true; + } else if (strcmp(name, ARENA_SEC) == 0) { + obj->efile.arena_data = data; + obj->efile.arena_data_shndx = idx; } else { pr_info("elf: skipping unrecognized data section(%d) %s\n", idx, name); } - } else if (sh.sh_type == SHT_REL) { - int nr_sects = obj->efile.nr_reloc_sects; - void *sects = obj->efile.reloc_sects; - int sec = sh.sh_info; /* points to other section */ + } else if (sh->sh_type == SHT_REL) { + int targ_sec_idx = sh->sh_info; /* points to other section */ + + if (sh->sh_entsize != sizeof(Elf64_Rel) || + targ_sec_idx >= obj->efile.sec_cnt) + return -LIBBPF_ERRNO__FORMAT; /* Only do relo for section with exec instructions */ - if (!section_have_execinstr(obj, sec) && + if (!section_have_execinstr(obj, targ_sec_idx) && strcmp(name, ".rel" STRUCT_OPS_SEC) && + strcmp(name, ".rel" STRUCT_OPS_LINK_SEC) && + strcmp(name, ".rel?" STRUCT_OPS_SEC) && + strcmp(name, ".rel?" STRUCT_OPS_LINK_SEC) && strcmp(name, ".rel" MAPS_ELF_SEC)) { pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n", - idx, name, sec, - elf_sec_name(obj, elf_sec_by_idx(obj, sec)) ?: "<?>"); + idx, name, targ_sec_idx, + elf_sec_name(obj, elf_sec_by_idx(obj, targ_sec_idx)) ?: "<?>"); continue; } - sects = libbpf_reallocarray(sects, nr_sects + 1, - sizeof(*obj->efile.reloc_sects)); - if (!sects) - return -ENOMEM; - - obj->efile.reloc_sects = sects; - obj->efile.nr_reloc_sects++; - - obj->efile.reloc_sects[nr_sects].shdr = sh; - obj->efile.reloc_sects[nr_sects].data = data; - } else if (sh.sh_type == SHT_NOBITS && strcmp(name, BSS_SEC) == 0) { - obj->efile.bss = data; - obj->efile.bss_shndx = idx; + sec_desc->sec_type = SEC_RELO; + sec_desc->shdr = sh; + sec_desc->data = data; + } else if (sh->sh_type == SHT_NOBITS && (strcmp(name, BSS_SEC) == 0 || + str_has_pfx(name, BSS_SEC "."))) { + sec_desc->sec_type = SEC_BSS; + sec_desc->shdr = sh; + sec_desc->data = data; } else { pr_info("elf: skipping section(%d) %s (size %zu)\n", idx, name, - (size_t)sh.sh_size); + (size_t)sh->sh_size); } } @@ -2943,42 +3879,65 @@ static int bpf_object__elf_collect(struct bpf_object *obj) } /* sort BPF programs by section name and in-section instruction offset - * for faster search */ - qsort(obj->programs, obj->nr_programs, sizeof(*obj->programs), cmp_progs); + * for faster search + */ + if (obj->nr_programs) + qsort(obj->programs, obj->nr_programs, sizeof(*obj->programs), cmp_progs); return bpf_object__init_btf(obj, btf_data, btf_ext_data); } -static bool sym_is_extern(const GElf_Sym *sym) +static bool sym_is_extern(const Elf64_Sym *sym) { - int bind = GELF_ST_BIND(sym->st_info); + int bind = ELF64_ST_BIND(sym->st_info); /* externs are symbols w/ type=NOTYPE, bind=GLOBAL|WEAK, section=UND */ return sym->st_shndx == SHN_UNDEF && (bind == STB_GLOBAL || bind == STB_WEAK) && - GELF_ST_TYPE(sym->st_info) == STT_NOTYPE; + ELF64_ST_TYPE(sym->st_info) == STT_NOTYPE; +} + +static bool sym_is_subprog(const Elf64_Sym *sym, int text_shndx) +{ + int bind = ELF64_ST_BIND(sym->st_info); + int type = ELF64_ST_TYPE(sym->st_info); + + /* in .text section */ + if (sym->st_shndx != text_shndx) + return false; + + /* local function */ + if (bind == STB_LOCAL && type == STT_SECTION) + return true; + + /* global function */ + return bind == STB_GLOBAL && type == STT_FUNC; } static int find_extern_btf_id(const struct btf *btf, const char *ext_name) { const struct btf_type *t; - const char *var_name; + const char *tname; int i, n; if (!btf) return -ESRCH; - n = btf__get_nr_types(btf); - for (i = 1; i <= n; i++) { + n = btf__type_cnt(btf); + for (i = 1; i < n; i++) { t = btf__type_by_id(btf, i); - if (!btf_is_var(t)) + if (!btf_is_var(t) && !btf_is_func(t)) continue; - var_name = btf__name_by_offset(btf, t->name_off); - if (strcmp(var_name, ext_name)) + tname = btf__name_by_offset(btf, t->name_off); + if (strcmp(tname, ext_name)) continue; - if (btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN) + if (btf_is_var(t) && + btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN) + return -EINVAL; + + if (btf_is_func(t) && btf_func_linkage(t) != BTF_FUNC_EXTERN) return -EINVAL; return i; @@ -2995,8 +3954,8 @@ static int find_extern_sec_btf_id(struct btf *btf, int ext_btf_id) { if (!btf) return -ESRCH; - n = btf__get_nr_types(btf); - for (i = 1; i <= n; i++) { + n = btf__type_cnt(btf); + for (i = 1; i < n; i++) { t = btf__type_by_id(btf, i); if (!btf_is_datasec(t)) @@ -3043,6 +4002,10 @@ static enum kcfg_type find_kcfg_type(const struct btf *btf, int id, if (strcmp(name, "libbpf_tristate")) return KCFG_UNKNOWN; return KCFG_TRISTATE; + case BTF_KIND_ENUM64: + if (strcmp(name, "libbpf_tristate")) + return KCFG_UNKNOWN; + return KCFG_TRISTATE; case BTF_KIND_ARRAY: if (btf_array(t)->nelems == 0) return KCFG_UNKNOWN; @@ -3080,8 +4043,8 @@ static int find_int_btf_id(const struct btf *btf) const struct btf_type *t; int i, n; - n = btf__get_nr_types(btf); - for (i = 1; i <= n; i++) { + n = btf__type_cnt(btf); + for (i = 1; i < n; i++) { t = btf__type_by_id(btf, i); if (btf_is_int(t) && btf_int_bits(t) == 32) @@ -3091,34 +4054,79 @@ static int find_int_btf_id(const struct btf *btf) return 0; } +static int add_dummy_ksym_var(struct btf *btf) +{ + int i, int_btf_id, sec_btf_id, dummy_var_btf_id; + const struct btf_var_secinfo *vs; + const struct btf_type *sec; + + if (!btf) + return 0; + + sec_btf_id = btf__find_by_name_kind(btf, KSYMS_SEC, + BTF_KIND_DATASEC); + if (sec_btf_id < 0) + return 0; + + sec = btf__type_by_id(btf, sec_btf_id); + vs = btf_var_secinfos(sec); + for (i = 0; i < btf_vlen(sec); i++, vs++) { + const struct btf_type *vt; + + vt = btf__type_by_id(btf, vs->type); + if (btf_is_func(vt)) + break; + } + + /* No func in ksyms sec. No need to add dummy var. */ + if (i == btf_vlen(sec)) + return 0; + + int_btf_id = find_int_btf_id(btf); + dummy_var_btf_id = btf__add_var(btf, + "dummy_ksym", + BTF_VAR_GLOBAL_ALLOCATED, + int_btf_id); + if (dummy_var_btf_id < 0) + pr_warn("cannot create a dummy_ksym var\n"); + + return dummy_var_btf_id; +} + static int bpf_object__collect_externs(struct bpf_object *obj) { struct btf_type *sec, *kcfg_sec = NULL, *ksym_sec = NULL; const struct btf_type *t; struct extern_desc *ext; - int i, n, off; + int i, n, off, dummy_var_btf_id; const char *ext_name, *sec_name; + size_t ext_essent_len; Elf_Scn *scn; - GElf_Shdr sh; + Elf64_Shdr *sh; if (!obj->efile.symbols) return 0; scn = elf_sec_by_idx(obj, obj->efile.symbols_shndx); - if (elf_sec_hdr(obj, scn, &sh)) + sh = elf_sec_hdr(obj, scn); + if (!sh || sh->sh_entsize != sizeof(Elf64_Sym)) return -LIBBPF_ERRNO__FORMAT; - n = sh.sh_size / sh.sh_entsize; + dummy_var_btf_id = add_dummy_ksym_var(obj->btf); + if (dummy_var_btf_id < 0) + return dummy_var_btf_id; + + n = sh->sh_size / sh->sh_entsize; pr_debug("looking for externs among %d symbols...\n", n); for (i = 0; i < n; i++) { - GElf_Sym sym; + Elf64_Sym *sym = elf_sym_by_idx(obj, i); - if (!gelf_getsym(obj->efile.symbols, i, &sym)) + if (!sym) return -LIBBPF_ERRNO__FORMAT; - if (!sym_is_extern(&sym)) + if (!sym_is_extern(sym)) continue; - ext_name = elf_sym_str(obj, sym.st_name); + ext_name = elf_sym_str(obj, sym->st_name); if (!ext_name || !ext_name[0]) continue; @@ -3140,7 +4148,15 @@ static int bpf_object__collect_externs(struct bpf_object *obj) t = btf__type_by_id(obj->btf, ext->btf_id); ext->name = btf__name_by_offset(obj->btf, t->name_off); ext->sym_idx = i; - ext->is_weak = GELF_ST_BIND(sym.st_info) == STB_WEAK; + ext->is_weak = ELF64_ST_BIND(sym->st_info) == STB_WEAK; + + ext_essent_len = bpf_core_essential_name_len(ext->name); + ext->essent_name = NULL; + if (ext_essent_len != strlen(ext->name)) { + ext->essent_name = strndup(ext->name, ext_essent_len); + if (!ext->essent_name) + return -ENOMEM; + } ext->sec_btf_id = find_extern_sec_btf_id(obj->btf, ext->btf_id); if (ext->sec_btf_id <= 0) { @@ -3152,6 +4168,11 @@ static int bpf_object__collect_externs(struct bpf_object *obj) sec_name = btf__name_by_offset(obj->btf, sec->name_off); if (strcmp(sec_name, KCONFIG_SEC) == 0) { + if (btf_is_func(t)) { + pr_warn("extern function %s is unsupported under %s section\n", + ext->name, KCONFIG_SEC); + return -ENOTSUP; + } kcfg_sec = sec; ext->type = EXT_KCFG; ext->kcfg.sz = btf__resolve_size(obj->btf, t->type); @@ -3167,9 +4188,9 @@ static int bpf_object__collect_externs(struct bpf_object *obj) return -EINVAL; } ext->kcfg.type = find_kcfg_type(obj->btf, t->type, - &ext->kcfg.is_signed); + &ext->kcfg.is_signed); if (ext->kcfg.type == KCFG_UNKNOWN) { - pr_warn("extern (kcfg) '%s' type is unsupported\n", ext_name); + pr_warn("extern (kcfg) '%s': type is unsupported\n", ext_name); return -ENOTSUP; } } else if (strcmp(sec_name, KSYMS_SEC) == 0) { @@ -3199,7 +4220,14 @@ static int bpf_object__collect_externs(struct bpf_object *obj) * extern variables in DATASEC */ int int_btf_id = find_int_btf_id(obj->btf); + /* For extern function, a dummy_var added earlier + * will be used to replace the vs->type and + * its name string will be used to refill + * the missing param's name. + */ + const struct btf_type *dummy_var; + dummy_var = btf__type_by_id(obj->btf, dummy_var_btf_id); for (i = 0; i < obj->nr_extern; i++) { ext = &obj->externs[i]; if (ext->type != EXT_KSYM) @@ -3218,12 +4246,32 @@ static int bpf_object__collect_externs(struct bpf_object *obj) ext_name = btf__name_by_offset(obj->btf, vt->name_off); ext = find_extern_by_name(obj, ext_name); if (!ext) { - pr_warn("failed to find extern definition for BTF var '%s'\n", - ext_name); + pr_warn("failed to find extern definition for BTF %s '%s'\n", + btf_kind_str(vt), ext_name); return -ESRCH; } - btf_var(vt)->linkage = BTF_VAR_GLOBAL_ALLOCATED; - vt->type = int_btf_id; + if (btf_is_func(vt)) { + const struct btf_type *func_proto; + struct btf_param *param; + int j; + + func_proto = btf__type_by_id(obj->btf, + vt->type); + param = btf_params(func_proto); + /* Reuse the dummy_var string if the + * func proto does not have param name. + */ + for (j = 0; j < btf_vlen(func_proto); j++) + if (param[j].type && !param[j].name_off) + param[j].name_off = + dummy_var->name_off; + vs->type = dummy_var_btf_id; + vt->info &= ~0xffff; + vt->info |= BTF_FUNC_GLOBAL; + } else { + btf_var(vt)->linkage = BTF_VAR_GLOBAL_ALLOCATED; + vt->type = int_btf_id; + } vs->offset = off; vs->size = sizeof(int); } @@ -3264,23 +4312,9 @@ static int bpf_object__collect_externs(struct bpf_object *obj) return 0; } -struct bpf_program * -bpf_object__find_program_by_title(const struct bpf_object *obj, - const char *title) +static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog) { - struct bpf_program *pos; - - bpf_object__for_each_program(pos, obj) { - if (pos->sec_name && !strcmp(pos->sec_name, title)) - return pos; - } - return NULL; -} - -static bool prog_is_subprog(const struct bpf_object *obj, - const struct bpf_program *prog) -{ - return prog->sec_idx == obj->efile.text_shndx && obj->has_subcalls; + return prog->sec_idx == obj->efile.text_shndx && obj->nr_programs > 1; } struct bpf_program * @@ -3295,43 +4329,50 @@ bpf_object__find_program_by_name(const struct bpf_object *obj, if (!strcmp(prog->name, name)) return prog; } - return NULL; + return errno = ENOENT, NULL; } static bool bpf_object__shndx_is_data(const struct bpf_object *obj, int shndx) { - return shndx == obj->efile.data_shndx || - shndx == obj->efile.bss_shndx || - shndx == obj->efile.rodata_shndx; + switch (obj->efile.secs[shndx].sec_type) { + case SEC_BSS: + case SEC_DATA: + case SEC_RODATA: + return true; + default: + return false; + } } static bool bpf_object__shndx_is_maps(const struct bpf_object *obj, int shndx) { - return shndx == obj->efile.maps_shndx || - shndx == obj->efile.btf_maps_shndx; + return shndx == obj->efile.btf_maps_shndx; } static enum libbpf_map_type bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx) { - if (shndx == obj->efile.data_shndx) - return LIBBPF_MAP_DATA; - else if (shndx == obj->efile.bss_shndx) + if (shndx == obj->efile.symbols_shndx) + return LIBBPF_MAP_KCONFIG; + + switch (obj->efile.secs[shndx].sec_type) { + case SEC_BSS: return LIBBPF_MAP_BSS; - else if (shndx == obj->efile.rodata_shndx) + case SEC_DATA: + return LIBBPF_MAP_DATA; + case SEC_RODATA: return LIBBPF_MAP_RODATA; - else if (shndx == obj->efile.symbols_shndx) - return LIBBPF_MAP_KCONFIG; - else + default: return LIBBPF_MAP_UNSPEC; + } } static int bpf_program__record_reloc(struct bpf_program *prog, struct reloc_desc *reloc_desc, __u32 insn_idx, const char *sym_name, - const GElf_Sym *sym, const GElf_Rel *rel) + const Elf64_Sym *sym, const Elf64_Rel *rel) { struct bpf_insn *insn = &prog->insns[insn_idx]; size_t map_idx, nr_maps = prog->obj->nr_maps; @@ -3341,10 +4382,40 @@ static int bpf_program__record_reloc(struct bpf_program *prog, const char *sym_sec_name; struct bpf_map *map; - reloc_desc->processed = false; + if (!is_call_insn(insn) && !is_ldimm64_insn(insn)) { + pr_warn("prog '%s': invalid relo against '%s' for insns[%d].code 0x%x\n", + prog->name, sym_name, insn_idx, insn->code); + return -LIBBPF_ERRNO__RELOC; + } + + if (sym_is_extern(sym)) { + int sym_idx = ELF64_R_SYM(rel->r_info); + int i, n = obj->nr_extern; + struct extern_desc *ext; + + for (i = 0; i < n; i++) { + ext = &obj->externs[i]; + if (ext->sym_idx == sym_idx) + break; + } + if (i >= n) { + pr_warn("prog '%s': extern relo failed to find extern for '%s' (%d)\n", + prog->name, sym_name, sym_idx); + return -LIBBPF_ERRNO__RELOC; + } + pr_debug("prog '%s': found extern #%d '%s' (sym %d) for insn #%u\n", + prog->name, i, ext->name, ext->sym_idx, insn_idx); + if (insn->code == (BPF_JMP | BPF_CALL)) + reloc_desc->type = RELO_EXTERN_CALL; + else + reloc_desc->type = RELO_EXTERN_LD64; + reloc_desc->insn_idx = insn_idx; + reloc_desc->ext_idx = i; + return 0; + } /* sub-program call relocation */ - if (insn->code == (BPF_JMP | BPF_CALL)) { + if (is_call_insn(insn)) { if (insn->src_reg != BPF_PSEUDO_CALL) { pr_warn("prog '%s': incorrect bpf_call opcode\n", prog->name); return -LIBBPF_ERRNO__RELOC; @@ -3367,44 +4438,41 @@ static int bpf_program__record_reloc(struct bpf_program *prog, return 0; } - if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) { - pr_warn("prog '%s': invalid relo against '%s' for insns[%d].code 0x%x\n", - prog->name, sym_name, insn_idx, insn->code); + if (!shdr_idx || shdr_idx >= SHN_LORESERVE) { + pr_warn("prog '%s': invalid relo against '%s' in special section 0x%x; forgot to initialize global var?..\n", + prog->name, sym_name, shdr_idx); return -LIBBPF_ERRNO__RELOC; } - if (sym_is_extern(sym)) { - int sym_idx = GELF_R_SYM(rel->r_info); - int i, n = obj->nr_extern; - struct extern_desc *ext; - - for (i = 0; i < n; i++) { - ext = &obj->externs[i]; - if (ext->sym_idx == sym_idx) - break; - } - if (i >= n) { - pr_warn("prog '%s': extern relo failed to find extern for '%s' (%d)\n", - prog->name, sym_name, sym_idx); + /* loading subprog addresses */ + if (sym_is_subprog(sym, obj->efile.text_shndx)) { + /* global_func: sym->st_value = offset in the section, insn->imm = 0. + * local_func: sym->st_value = 0, insn->imm = offset in the section. + */ + if ((sym->st_value % BPF_INSN_SZ) || (insn->imm % BPF_INSN_SZ)) { + pr_warn("prog '%s': bad subprog addr relo against '%s' at offset %zu+%d\n", + prog->name, sym_name, (size_t)sym->st_value, insn->imm); return -LIBBPF_ERRNO__RELOC; } - pr_debug("prog '%s': found extern #%d '%s' (sym %d) for insn #%u\n", - prog->name, i, ext->name, ext->sym_idx, insn_idx); - reloc_desc->type = RELO_EXTERN; + + reloc_desc->type = RELO_SUBPROG_ADDR; reloc_desc->insn_idx = insn_idx; - reloc_desc->sym_off = i; /* sym_off stores extern index */ + reloc_desc->sym_off = sym->st_value; return 0; } - if (!shdr_idx || shdr_idx >= SHN_LORESERVE) { - pr_warn("prog '%s': invalid relo against '%s' in special section 0x%x; forgot to initialize global var?..\n", - prog->name, sym_name, shdr_idx); - return -LIBBPF_ERRNO__RELOC; - } - type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx); sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx)); + /* arena data relocation */ + if (shdr_idx == obj->efile.arena_data_shndx) { + reloc_desc->type = RELO_DATA; + reloc_desc->insn_idx = insn_idx; + reloc_desc->map_idx = obj->arena_map - obj->maps; + reloc_desc->sym_off = sym->st_value; + return 0; + } + /* generic map reference relocation */ if (type == LIBBPF_MAP_UNSPEC) { if (!bpf_object__shndx_is_maps(obj, shdr_idx)) { @@ -3443,7 +4511,7 @@ static int bpf_program__record_reloc(struct bpf_program *prog, } for (map_idx = 0; map_idx < nr_maps; map_idx++) { map = &obj->maps[map_idx]; - if (map->libbpf_type != type) + if (map->libbpf_type != type || map->sec_idx != sym->st_shndx) continue; pr_debug("prog '%s': found data map %zd (%s, sec %d, off %zu) for insn %u\n", prog->name, map_idx, map->name, map->sec_idx, @@ -3475,6 +4543,9 @@ static struct bpf_program *find_prog_by_sec_insn(const struct bpf_object *obj, int l = 0, r = obj->nr_programs - 1, m; struct bpf_program *prog; + if (!obj->nr_programs) + return NULL; + while (l < r) { m = l + (r - l + 1) / 2; prog = &obj->programs[m]; @@ -3495,21 +4566,30 @@ static struct bpf_program *find_prog_by_sec_insn(const struct bpf_object *obj, } static int -bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data *data) +bpf_object__collect_prog_relos(struct bpf_object *obj, Elf64_Shdr *shdr, Elf_Data *data) { - Elf_Data *symbols = obj->efile.symbols; const char *relo_sec_name, *sec_name; - size_t sec_idx = shdr->sh_info; + size_t sec_idx = shdr->sh_info, sym_idx; struct bpf_program *prog; struct reloc_desc *relos; int err, i, nrels; const char *sym_name; __u32 insn_idx; - GElf_Sym sym; - GElf_Rel rel; + Elf_Scn *scn; + Elf_Data *scn_data; + Elf64_Sym *sym; + Elf64_Rel *rel; + + if (sec_idx >= obj->efile.sec_cnt) + return -EINVAL; + + scn = elf_sec_by_idx(obj, sec_idx); + scn_data = elf_sec_data(obj, scn); + if (!scn_data) + return -LIBBPF_ERRNO__FORMAT; relo_sec_name = elf_sec_str(obj, shdr->sh_name); - sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); + sec_name = elf_sec_name(obj, scn); if (!relo_sec_name || !sec_name) return -EINVAL; @@ -3518,32 +4598,43 @@ bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data nrels = shdr->sh_size / shdr->sh_entsize; for (i = 0; i < nrels; i++) { - if (!gelf_getrel(data, i, &rel)) { + rel = elf_rel_by_idx(data, i); + if (!rel) { pr_warn("sec '%s': failed to get relo #%d\n", relo_sec_name, i); return -LIBBPF_ERRNO__FORMAT; } - if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) { - pr_warn("sec '%s': symbol 0x%zx not found for relo #%d\n", - relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i); + + sym_idx = ELF64_R_SYM(rel->r_info); + sym = elf_sym_by_idx(obj, sym_idx); + if (!sym) { + pr_warn("sec '%s': symbol #%zu not found for relo #%d\n", + relo_sec_name, sym_idx, i); return -LIBBPF_ERRNO__FORMAT; } - if (rel.r_offset % BPF_INSN_SZ) { + + if (sym->st_shndx >= obj->efile.sec_cnt) { + pr_warn("sec '%s': corrupted symbol #%zu pointing to invalid section #%zu for relo #%d\n", + relo_sec_name, sym_idx, (size_t)sym->st_shndx, i); + return -LIBBPF_ERRNO__FORMAT; + } + + if (rel->r_offset % BPF_INSN_SZ || rel->r_offset >= scn_data->d_size) { pr_warn("sec '%s': invalid offset 0x%zx for relo #%d\n", - relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i); + relo_sec_name, (size_t)rel->r_offset, i); return -LIBBPF_ERRNO__FORMAT; } - insn_idx = rel.r_offset / BPF_INSN_SZ; + insn_idx = rel->r_offset / BPF_INSN_SZ; /* relocations against static functions are recorded as * relocations against the section that contains a function; * in such case, symbol will be STT_SECTION and sym.st_name * will point to empty string (0), so fetch section name * instead */ - if (GELF_ST_TYPE(sym.st_info) == STT_SECTION && sym.st_name == 0) - sym_name = elf_sec_name(obj, elf_sec_by_idx(obj, sym.st_shndx)); + if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION && sym->st_name == 0) + sym_name = elf_sec_name(obj, elf_sec_by_idx(obj, sym->st_shndx)); else - sym_name = elf_sym_str(obj, sym.st_name); + sym_name = elf_sym_str(obj, sym->st_name); sym_name = sym_name ?: "<?"; pr_debug("sec '%s': relo #%d: insn #%u against '%s'\n", @@ -3551,9 +4642,9 @@ bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx); if (!prog) { - pr_warn("sec '%s': relo #%d: program not found in section '%s' for insn #%u\n", + pr_debug("sec '%s': relo #%d: couldn't find program in section '%s' for insn #%u, probably overridden weak function, skipping...\n", relo_sec_name, i, sec_name, insn_idx); - return -LIBBPF_ERRNO__RELOC; + continue; } relos = libbpf_reallocarray(prog->reloc_desc, @@ -3565,7 +4656,7 @@ bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data /* adjust insn_idx to local BPF program frame of reference */ insn_idx -= prog->sec_insn_off; err = bpf_program__record_reloc(prog, &relos[prog->nr_reloc], - insn_idx, sym_name, &sym, &rel); + insn_idx, sym_name, sym, rel); if (err) return err; @@ -3574,76 +4665,126 @@ bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data return 0; } -static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map) +static int map_fill_btf_type_info(struct bpf_object *obj, struct bpf_map *map) { - struct bpf_map_def *def = &map->def; - __u32 key_type_id = 0, value_type_id = 0; - int ret; + int id; + + if (!obj->btf) + return -ENOENT; /* if it's BTF-defined map, we don't need to search for type IDs. * For struct_ops map, it does not need btf_key_type_id and * btf_value_type_id. */ - if (map->sec_idx == obj->efile.btf_maps_shndx || - bpf_map__is_struct_ops(map)) + if (map->sec_idx == obj->efile.btf_maps_shndx || bpf_map__is_struct_ops(map)) return 0; - if (!bpf_map__is_internal(map)) { - ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size, - def->value_size, &key_type_id, - &value_type_id); - } else { - /* - * LLVM annotates global data differently in BTF, that is, - * only as '.data', '.bss' or '.rodata'. - */ - ret = btf__find_by_name(obj->btf, - libbpf_type_to_btf_name[map->libbpf_type]); + /* + * LLVM annotates global data differently in BTF, that is, + * only as '.data', '.bss' or '.rodata'. + */ + if (!bpf_map__is_internal(map)) + return -ENOENT; + + id = btf__find_by_name(obj->btf, map->real_name); + if (id < 0) + return id; + + map->btf_key_type_id = 0; + map->btf_value_type_id = id; + return 0; +} + +static int bpf_get_map_info_from_fdinfo(int fd, struct bpf_map_info *info) +{ + char file[PATH_MAX], buff[4096]; + FILE *fp; + __u32 val; + int err; + + snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd); + memset(info, 0, sizeof(*info)); + + fp = fopen(file, "re"); + if (!fp) { + err = -errno; + pr_warn("failed to open %s: %d. No procfs support?\n", file, + err); + return err; + } + + while (fgets(buff, sizeof(buff), fp)) { + if (sscanf(buff, "map_type:\t%u", &val) == 1) + info->type = val; + else if (sscanf(buff, "key_size:\t%u", &val) == 1) + info->key_size = val; + else if (sscanf(buff, "value_size:\t%u", &val) == 1) + info->value_size = val; + else if (sscanf(buff, "max_entries:\t%u", &val) == 1) + info->max_entries = val; + else if (sscanf(buff, "map_flags:\t%i", &val) == 1) + info->map_flags = val; } - if (ret < 0) - return ret; - map->btf_key_type_id = key_type_id; - map->btf_value_type_id = bpf_map__is_internal(map) ? - ret : value_type_id; + fclose(fp); + + return 0; +} + +bool bpf_map__autocreate(const struct bpf_map *map) +{ + return map->autocreate; +} + +int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate) +{ + if (map->obj->loaded) + return libbpf_err(-EBUSY); + + map->autocreate = autocreate; return 0; } int bpf_map__reuse_fd(struct bpf_map *map, int fd) { - struct bpf_map_info info = {}; - __u32 len = sizeof(info); + struct bpf_map_info info; + __u32 len = sizeof(info), name_len; int new_fd, err; char *new_name; - err = bpf_obj_get_info_by_fd(fd, &info, &len); + memset(&info, 0, len); + err = bpf_map_get_info_by_fd(fd, &info, &len); + if (err && errno == EINVAL) + err = bpf_get_map_info_from_fdinfo(fd, &info); if (err) - return err; + return libbpf_err(err); + + name_len = strlen(info.name); + if (name_len == BPF_OBJ_NAME_LEN - 1 && strncmp(map->name, info.name, name_len) == 0) + new_name = strdup(map->name); + else + new_name = strdup(info.name); - new_name = strdup(info.name); if (!new_name) - return -errno; + return libbpf_err(-errno); - new_fd = open("/", O_RDONLY | O_CLOEXEC); + /* + * Like dup(), but make sure new FD is >= 3 and has O_CLOEXEC set. + * This is similar to what we do in ensure_good_fd(), but without + * closing original FD. + */ + new_fd = fcntl(fd, F_DUPFD_CLOEXEC, 3); if (new_fd < 0) { err = -errno; goto err_free_new_name; } - new_fd = dup3(fd, new_fd, O_CLOEXEC); - if (new_fd < 0) { - err = -errno; - goto err_close_new_fd; - } + err = reuse_fd(map->fd, new_fd); + if (err) + goto err_free_new_name; - err = zclose(map->fd); - if (err) { - err = -errno; - goto err_close_new_fd; - } free(map->name); - map->fd = new_fd; map->name = new_name; map->def.type = info.type; map->def.key_size = info.key_size; @@ -3653,14 +4794,13 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd) map->btf_key_type_id = info.btf_key_type_id; map->btf_value_type_id = info.btf_value_type_id; map->reused = true; + map->map_extra = info.map_extra; return 0; -err_close_new_fd: - close(new_fd); err_free_new_name: free(new_name); - return err; + return libbpf_err(err); } __u32 bpf_map__max_entries(const struct bpf_map *map) @@ -3668,42 +4808,105 @@ __u32 bpf_map__max_entries(const struct bpf_map *map) return map->def.max_entries; } +struct bpf_map *bpf_map__inner_map(struct bpf_map *map) +{ + if (!bpf_map_type__is_map_in_map(map->def.type)) + return errno = EINVAL, NULL; + + return map->inner_map; +} + int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries) { - if (map->fd >= 0) - return -EBUSY; + if (map->obj->loaded) + return libbpf_err(-EBUSY); + map->def.max_entries = max_entries; + + /* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */ + if (map_is_ringbuf(map)) + map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); + return 0; } -int bpf_map__resize(struct bpf_map *map, __u32 max_entries) +static int bpf_object_prepare_token(struct bpf_object *obj) { - if (!map || !max_entries) - return -EINVAL; + const char *bpffs_path; + int bpffs_fd = -1, token_fd, err; + bool mandatory; + enum libbpf_print_level level; + + /* token is explicitly prevented */ + if (obj->token_path && obj->token_path[0] == '\0') { + pr_debug("object '%s': token is prevented, skipping...\n", obj->name); + return 0; + } + + mandatory = obj->token_path != NULL; + level = mandatory ? LIBBPF_WARN : LIBBPF_DEBUG; + + bpffs_path = obj->token_path ?: BPF_FS_DEFAULT_PATH; + bpffs_fd = open(bpffs_path, O_DIRECTORY, O_RDWR); + if (bpffs_fd < 0) { + err = -errno; + __pr(level, "object '%s': failed (%d) to open BPF FS mount at '%s'%s\n", + obj->name, err, bpffs_path, + mandatory ? "" : ", skipping optional step..."); + return mandatory ? err : 0; + } + + token_fd = bpf_token_create(bpffs_fd, 0); + close(bpffs_fd); + if (token_fd < 0) { + if (!mandatory && token_fd == -ENOENT) { + pr_debug("object '%s': BPF FS at '%s' doesn't have BPF token delegation set up, skipping...\n", + obj->name, bpffs_path); + return 0; + } + __pr(level, "object '%s': failed (%d) to create BPF token from '%s'%s\n", + obj->name, token_fd, bpffs_path, + mandatory ? "" : ", skipping optional step..."); + return mandatory ? token_fd : 0; + } + + obj->feat_cache = calloc(1, sizeof(*obj->feat_cache)); + if (!obj->feat_cache) { + close(token_fd); + return -ENOMEM; + } + + obj->token_fd = token_fd; + obj->feat_cache->token_fd = token_fd; - return bpf_map__set_max_entries(map, max_entries); + return 0; } static int bpf_object__probe_loading(struct bpf_object *obj) { - struct bpf_load_program_attr attr; char *cp, errmsg[STRERR_BUFSIZE]; struct bpf_insn insns[] = { BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }; - int ret; + int ret, insn_cnt = ARRAY_SIZE(insns); + LIBBPF_OPTS(bpf_prog_load_opts, opts, + .token_fd = obj->token_fd, + .prog_flags = obj->token_fd ? BPF_F_TOKEN_FD : 0, + ); - /* make sure basic loading works */ + if (obj->gen_loader) + return 0; - memset(&attr, 0, sizeof(attr)); - attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; - attr.insns = insns; - attr.insns_cnt = ARRAY_SIZE(insns); - attr.license = "GPL"; + ret = bump_rlimit_memlock(); + if (ret) + pr_warn("Failed to bump RLIMIT_MEMLOCK (err = %d), you might need to do it explicitly!\n", ret); - ret = bpf_load_program_xattr(&attr, NULL, 0); + /* make sure basic loading works */ + ret = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, &opts); + if (ret < 0) + ret = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, &opts); if (ret < 0) { ret = errno; cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg)); @@ -3718,322 +4921,34 @@ bpf_object__probe_loading(struct bpf_object *obj) return 0; } -static int probe_fd(int fd) -{ - if (fd >= 0) - close(fd); - return fd >= 0; -} - -static int probe_kern_prog_name(void) +bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) { - struct bpf_load_program_attr attr; - struct bpf_insn insns[] = { - BPF_MOV64_IMM(BPF_REG_0, 0), - BPF_EXIT_INSN(), - }; - int ret; - - /* make sure loading with name works */ - - memset(&attr, 0, sizeof(attr)); - attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; - attr.insns = insns; - attr.insns_cnt = ARRAY_SIZE(insns); - attr.license = "GPL"; - attr.name = "test"; - ret = bpf_load_program_xattr(&attr, NULL, 0); - return probe_fd(ret); -} - -static int probe_kern_global_data(void) -{ - struct bpf_load_program_attr prg_attr; - struct bpf_create_map_attr map_attr; - char *cp, errmsg[STRERR_BUFSIZE]; - struct bpf_insn insns[] = { - BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16), - BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42), - BPF_MOV64_IMM(BPF_REG_0, 0), - BPF_EXIT_INSN(), - }; - int ret, map; - - memset(&map_attr, 0, sizeof(map_attr)); - map_attr.map_type = BPF_MAP_TYPE_ARRAY; - map_attr.key_size = sizeof(int); - map_attr.value_size = 32; - map_attr.max_entries = 1; - - map = bpf_create_map_xattr(&map_attr); - if (map < 0) { - ret = -errno; - cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg)); - pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n", - __func__, cp, -ret); - return ret; - } - - insns[0].imm = map; - - memset(&prg_attr, 0, sizeof(prg_attr)); - prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; - prg_attr.insns = insns; - prg_attr.insns_cnt = ARRAY_SIZE(insns); - prg_attr.license = "GPL"; - - ret = bpf_load_program_xattr(&prg_attr, NULL, 0); - close(map); - return probe_fd(ret); -} - -static int probe_kern_btf(void) -{ - static const char strs[] = "\0int"; - __u32 types[] = { - /* int */ - BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), - }; - - return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), - strs, sizeof(strs))); -} - -static int probe_kern_btf_func(void) -{ - static const char strs[] = "\0int\0x\0a"; - /* void x(int a) {} */ - __u32 types[] = { - /* int */ - BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ - /* FUNC_PROTO */ /* [2] */ - BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0), - BTF_PARAM_ENC(7, 1), - /* FUNC x */ /* [3] */ - BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2), - }; - - return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), - strs, sizeof(strs))); -} - -static int probe_kern_btf_func_global(void) -{ - static const char strs[] = "\0int\0x\0a"; - /* static void x(int a) {} */ - __u32 types[] = { - /* int */ - BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ - /* FUNC_PROTO */ /* [2] */ - BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0), - BTF_PARAM_ENC(7, 1), - /* FUNC x BTF_FUNC_GLOBAL */ /* [3] */ - BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2), - }; - - return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), - strs, sizeof(strs))); -} - -static int probe_kern_btf_datasec(void) -{ - static const char strs[] = "\0x\0.data"; - /* static int a; */ - __u32 types[] = { - /* int */ - BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ - /* VAR x */ /* [2] */ - BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1), - BTF_VAR_STATIC, - /* DATASEC val */ /* [3] */ - BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4), - BTF_VAR_SECINFO_ENC(2, 0, 4), - }; - - return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), - strs, sizeof(strs))); -} - -static int probe_kern_array_mmap(void) -{ - struct bpf_create_map_attr attr = { - .map_type = BPF_MAP_TYPE_ARRAY, - .map_flags = BPF_F_MMAPABLE, - .key_size = sizeof(int), - .value_size = sizeof(int), - .max_entries = 1, - }; - - return probe_fd(bpf_create_map_xattr(&attr)); -} - -static int probe_kern_exp_attach_type(void) -{ - struct bpf_load_program_attr attr; - struct bpf_insn insns[] = { - BPF_MOV64_IMM(BPF_REG_0, 0), - BPF_EXIT_INSN(), - }; - - memset(&attr, 0, sizeof(attr)); - /* use any valid combination of program type and (optional) - * non-zero expected attach type (i.e., not a BPF_CGROUP_INET_INGRESS) - * to see if kernel supports expected_attach_type field for - * BPF_PROG_LOAD command - */ - attr.prog_type = BPF_PROG_TYPE_CGROUP_SOCK; - attr.expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE; - attr.insns = insns; - attr.insns_cnt = ARRAY_SIZE(insns); - attr.license = "GPL"; - - return probe_fd(bpf_load_program_xattr(&attr, NULL, 0)); -} - -static int probe_kern_probe_read_kernel(void) -{ - struct bpf_load_program_attr attr; - struct bpf_insn insns[] = { - BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), /* r1 = r10 (fp) */ - BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), /* r1 += -8 */ - BPF_MOV64_IMM(BPF_REG_2, 8), /* r2 = 8 */ - BPF_MOV64_IMM(BPF_REG_3, 0), /* r3 = 0 */ - BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_probe_read_kernel), - BPF_EXIT_INSN(), - }; - - memset(&attr, 0, sizeof(attr)); - attr.prog_type = BPF_PROG_TYPE_KPROBE; - attr.insns = insns; - attr.insns_cnt = ARRAY_SIZE(insns); - attr.license = "GPL"; - - return probe_fd(bpf_load_program_xattr(&attr, NULL, 0)); -} - -static int probe_prog_bind_map(void) -{ - struct bpf_load_program_attr prg_attr; - struct bpf_create_map_attr map_attr; - char *cp, errmsg[STRERR_BUFSIZE]; - struct bpf_insn insns[] = { - BPF_MOV64_IMM(BPF_REG_0, 0), - BPF_EXIT_INSN(), - }; - int ret, map, prog; - - memset(&map_attr, 0, sizeof(map_attr)); - map_attr.map_type = BPF_MAP_TYPE_ARRAY; - map_attr.key_size = sizeof(int); - map_attr.value_size = 32; - map_attr.max_entries = 1; - - map = bpf_create_map_xattr(&map_attr); - if (map < 0) { - ret = -errno; - cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg)); - pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n", - __func__, cp, -ret); - return ret; - } - - memset(&prg_attr, 0, sizeof(prg_attr)); - prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; - prg_attr.insns = insns; - prg_attr.insns_cnt = ARRAY_SIZE(insns); - prg_attr.license = "GPL"; - - prog = bpf_load_program_xattr(&prg_attr, NULL, 0); - if (prog < 0) { - close(map); - return 0; - } - - ret = bpf_prog_bind_map(prog, map, NULL); - - close(map); - close(prog); - - return ret >= 0; -} - -enum kern_feature_result { - FEAT_UNKNOWN = 0, - FEAT_SUPPORTED = 1, - FEAT_MISSING = 2, -}; - -typedef int (*feature_probe_fn)(void); - -static struct kern_feature_desc { - const char *desc; - feature_probe_fn probe; - enum kern_feature_result res; -} feature_probes[__FEAT_CNT] = { - [FEAT_PROG_NAME] = { - "BPF program name", probe_kern_prog_name, - }, - [FEAT_GLOBAL_DATA] = { - "global variables", probe_kern_global_data, - }, - [FEAT_BTF] = { - "minimal BTF", probe_kern_btf, - }, - [FEAT_BTF_FUNC] = { - "BTF functions", probe_kern_btf_func, - }, - [FEAT_BTF_GLOBAL_FUNC] = { - "BTF global function", probe_kern_btf_func_global, - }, - [FEAT_BTF_DATASEC] = { - "BTF data section and variable", probe_kern_btf_datasec, - }, - [FEAT_ARRAY_MMAP] = { - "ARRAY map mmap()", probe_kern_array_mmap, - }, - [FEAT_EXP_ATTACH_TYPE] = { - "BPF_PROG_LOAD expected_attach_type attribute", - probe_kern_exp_attach_type, - }, - [FEAT_PROBE_READ_KERN] = { - "bpf_probe_read_kernel() helper", probe_kern_probe_read_kernel, - }, - [FEAT_PROG_BIND_MAP] = { - "BPF_PROG_BIND_MAP support", probe_prog_bind_map, - } -}; - -static bool kernel_supports(enum kern_feature_id feat_id) -{ - struct kern_feature_desc *feat = &feature_probes[feat_id]; - int ret; + if (obj->gen_loader) + /* To generate loader program assume the latest kernel + * to avoid doing extra prog_load, map_create syscalls. + */ + return true; - if (READ_ONCE(feat->res) == FEAT_UNKNOWN) { - ret = feat->probe(); - if (ret > 0) { - WRITE_ONCE(feat->res, FEAT_SUPPORTED); - } else if (ret == 0) { - WRITE_ONCE(feat->res, FEAT_MISSING); - } else { - pr_warn("Detection of kernel %s support failed: %d\n", feat->desc, ret); - WRITE_ONCE(feat->res, FEAT_MISSING); - } - } + if (obj->token_fd) + return feat_supported(obj->feat_cache, feat_id); - return READ_ONCE(feat->res) == FEAT_SUPPORTED; + return feat_supported(NULL, feat_id); } static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd) { - struct bpf_map_info map_info = {}; + struct bpf_map_info map_info; char msg[STRERR_BUFSIZE]; - __u32 map_info_len; - - map_info_len = sizeof(map_info); + __u32 map_info_len = sizeof(map_info); + int err; - if (bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len)) { - pr_warn("failed to get map info for map FD %d: %s\n", - map_fd, libbpf_strerror_r(errno, msg, sizeof(msg))); + memset(&map_info, 0, map_info_len); + err = bpf_map_get_info_by_fd(map_fd, &map_info, &map_info_len); + if (err && errno == EINVAL) + err = bpf_get_map_info_from_fdinfo(map_fd, &map_info); + if (err) { + pr_warn("failed to get map info for map FD %d: %s\n", map_fd, + libbpf_strerror_r(errno, msg, sizeof(msg))); return false; } @@ -4041,7 +4956,8 @@ static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd) map_info.key_size == map->def.key_size && map_info.value_size == map->def.value_size && map_info.max_entries == map->def.max_entries && - map_info.map_flags == map->def.map_flags); + map_info.map_flags == map->def.map_flags && + map_info.map_extra == map->map_extra); } static int @@ -4073,10 +4989,10 @@ bpf_object__reuse_map(struct bpf_map *map) } err = bpf_map__reuse_fd(map, pin_fd); - if (err) { - close(pin_fd); + close(pin_fd); + if (err) return err; - } + map->pinned = true; pr_debug("reused pinned map at '%s'\n", map->pin_path); @@ -4090,6 +5006,14 @@ bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map) char *cp, errmsg[STRERR_BUFSIZE]; int err, zero = 0; + if (obj->gen_loader) { + bpf_gen__map_update_elem(obj->gen_loader, map - obj->maps, + map->mmaped, map->def.value_size); + if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG) + bpf_gen__map_freeze(obj->gen_loader, map - obj->maps); + return 0; + } + err = bpf_map_update_elem(map->fd, &zero, map->mmaped, 0); if (err) { err = -errno; @@ -4115,45 +5039,37 @@ bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map) static void bpf_map__destroy(struct bpf_map *map); -static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map) +static bool map_is_created(const struct bpf_map *map) { - struct bpf_create_map_attr create_attr; - struct bpf_map_def *def = &map->def; + return map->obj->loaded || map->reused; +} - memset(&create_attr, 0, sizeof(create_attr)); +static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, bool is_inner) +{ + LIBBPF_OPTS(bpf_map_create_opts, create_attr); + struct bpf_map_def *def = &map->def; + const char *map_name = NULL; + int err = 0, map_fd; - if (kernel_supports(FEAT_PROG_NAME)) - create_attr.name = map->name; + if (kernel_supports(obj, FEAT_PROG_NAME)) + map_name = map->name; create_attr.map_ifindex = map->map_ifindex; - create_attr.map_type = def->type; create_attr.map_flags = def->map_flags; - create_attr.key_size = def->key_size; - create_attr.value_size = def->value_size; create_attr.numa_node = map->numa_node; + create_attr.map_extra = map->map_extra; + create_attr.token_fd = obj->token_fd; + if (obj->token_fd) + create_attr.map_flags |= BPF_F_TOKEN_FD; - if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !def->max_entries) { - int nr_cpus; - - nr_cpus = libbpf_num_possible_cpus(); - if (nr_cpus < 0) { - pr_warn("map '%s': failed to determine number of system CPUs: %d\n", - map->name, nr_cpus); - return nr_cpus; + if (bpf_map__is_struct_ops(map)) { + create_attr.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id; + if (map->mod_btf_fd >= 0) { + create_attr.value_type_btf_obj_fd = map->mod_btf_fd; + create_attr.map_flags |= BPF_F_VTYPE_BTF_OBJ_FD; } - pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus); - create_attr.max_entries = nr_cpus; - } else { - create_attr.max_entries = def->max_entries; } - if (bpf_map__is_struct_ops(map)) - create_attr.btf_vmlinux_value_type_id = - map->btf_vmlinux_value_type_id; - - create_attr.btf_fd = 0; - create_attr.btf_key_type_id = 0; - create_attr.btf_value_type_id = 0; - if (obj->btf && btf__fd(obj->btf) >= 0 && !bpf_map_find_btf_info(obj, map)) { + if (obj->btf && btf__fd(obj->btf) >= 0) { create_attr.btf_fd = btf__fd(obj->btf); create_attr.btf_key_type_id = map->btf_key_type_id; create_attr.btf_value_type_id = map->btf_value_type_id; @@ -4161,26 +5077,69 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map) if (bpf_map_type__is_map_in_map(def->type)) { if (map->inner_map) { - int err; - - err = bpf_object__create_map(obj, map->inner_map); + err = map_set_def_max_entries(map->inner_map); + if (err) + return err; + err = bpf_object__create_map(obj, map->inner_map, true); if (err) { pr_warn("map '%s': failed to create inner map: %d\n", map->name, err); return err; } - map->inner_map_fd = bpf_map__fd(map->inner_map); + map->inner_map_fd = map->inner_map->fd; } if (map->inner_map_fd >= 0) create_attr.inner_map_fd = map->inner_map_fd; } - map->fd = bpf_create_map_xattr(&create_attr); - if (map->fd < 0 && (create_attr.btf_key_type_id || - create_attr.btf_value_type_id)) { + switch (def->type) { + case BPF_MAP_TYPE_PERF_EVENT_ARRAY: + case BPF_MAP_TYPE_CGROUP_ARRAY: + case BPF_MAP_TYPE_STACK_TRACE: + case BPF_MAP_TYPE_ARRAY_OF_MAPS: + case BPF_MAP_TYPE_HASH_OF_MAPS: + case BPF_MAP_TYPE_DEVMAP: + case BPF_MAP_TYPE_DEVMAP_HASH: + case BPF_MAP_TYPE_CPUMAP: + case BPF_MAP_TYPE_XSKMAP: + case BPF_MAP_TYPE_SOCKMAP: + case BPF_MAP_TYPE_SOCKHASH: + case BPF_MAP_TYPE_QUEUE: + case BPF_MAP_TYPE_STACK: + case BPF_MAP_TYPE_ARENA: + create_attr.btf_fd = 0; + create_attr.btf_key_type_id = 0; + create_attr.btf_value_type_id = 0; + map->btf_key_type_id = 0; + map->btf_value_type_id = 0; + break; + case BPF_MAP_TYPE_STRUCT_OPS: + create_attr.btf_value_type_id = 0; + break; + default: + break; + } + + if (obj->gen_loader) { + bpf_gen__map_create(obj->gen_loader, def->type, map_name, + def->key_size, def->value_size, def->max_entries, + &create_attr, is_inner ? -1 : map - obj->maps); + /* We keep pretenting we have valid FD to pass various fd >= 0 + * checks by just keeping original placeholder FDs in place. + * See bpf_object__add_map() comment. + * This placeholder fd will not be used with any syscall and + * will be reset to -1 eventually. + */ + map_fd = map->fd; + } else { + map_fd = bpf_map_create(def->type, map_name, + def->key_size, def->value_size, + def->max_entries, &create_attr); + } + if (map_fd < 0 && (create_attr.btf_key_type_id || create_attr.btf_value_type_id)) { char *cp, errmsg[STRERR_BUFSIZE]; - int err = -errno; + err = -errno; cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n", map->name, cp, err); @@ -4189,38 +5148,57 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map) create_attr.btf_value_type_id = 0; map->btf_key_type_id = 0; map->btf_value_type_id = 0; - map->fd = bpf_create_map_xattr(&create_attr); + map_fd = bpf_map_create(def->type, map_name, + def->key_size, def->value_size, + def->max_entries, &create_attr); } - if (map->fd < 0) - return -errno; - if (bpf_map_type__is_map_in_map(def->type) && map->inner_map) { + if (obj->gen_loader) + map->inner_map->fd = -1; bpf_map__destroy(map->inner_map); zfree(&map->inner_map); } - return 0; + if (map_fd < 0) + return map_fd; + + /* obj->gen_loader case, prevent reuse_fd() from closing map_fd */ + if (map->fd == map_fd) + return 0; + + /* Keep placeholder FD value but now point it to the BPF map object. + * This way everything that relied on this map's FD (e.g., relocated + * ldimm64 instructions) will stay valid and won't need adjustments. + * map->fd stays valid but now point to what map_fd points to. + */ + return reuse_fd(map->fd, map_fd); } -static int init_map_slots(struct bpf_map *map) +static int init_map_in_map_slots(struct bpf_object *obj, struct bpf_map *map) { const struct bpf_map *targ_map; unsigned int i; - int fd, err; + int fd, err = 0; for (i = 0; i < map->init_slots_sz; i++) { if (!map->init_slots[i]) continue; targ_map = map->init_slots[i]; - fd = bpf_map__fd(targ_map); - err = bpf_map_update_elem(map->fd, &i, &fd, 0); + fd = targ_map->fd; + + if (obj->gen_loader) { + bpf_gen__populate_outer_map(obj->gen_loader, + map - obj->maps, i, + targ_map - obj->maps); + } else { + err = bpf_map_update_elem(map->fd, &i, &fd, 0); + } if (err) { err = -errno; pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n", - map->name, i, targ_map->name, - fd, err); + map->name, i, targ_map->name, fd, err); return err; } pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n", @@ -4233,6 +5211,75 @@ static int init_map_slots(struct bpf_map *map) return 0; } +static int init_prog_array_slots(struct bpf_object *obj, struct bpf_map *map) +{ + const struct bpf_program *targ_prog; + unsigned int i; + int fd, err; + + if (obj->gen_loader) + return -ENOTSUP; + + for (i = 0; i < map->init_slots_sz; i++) { + if (!map->init_slots[i]) + continue; + + targ_prog = map->init_slots[i]; + fd = bpf_program__fd(targ_prog); + + err = bpf_map_update_elem(map->fd, &i, &fd, 0); + if (err) { + err = -errno; + pr_warn("map '%s': failed to initialize slot [%d] to prog '%s' fd=%d: %d\n", + map->name, i, targ_prog->name, fd, err); + return err; + } + pr_debug("map '%s': slot [%d] set to prog '%s' fd=%d\n", + map->name, i, targ_prog->name, fd); + } + + zfree(&map->init_slots); + map->init_slots_sz = 0; + + return 0; +} + +static int bpf_object_init_prog_arrays(struct bpf_object *obj) +{ + struct bpf_map *map; + int i, err; + + for (i = 0; i < obj->nr_maps; i++) { + map = &obj->maps[i]; + + if (!map->init_slots_sz || map->def.type != BPF_MAP_TYPE_PROG_ARRAY) + continue; + + err = init_prog_array_slots(obj, map); + if (err < 0) + return err; + } + return 0; +} + +static int map_set_def_max_entries(struct bpf_map *map) +{ + if (map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !map->def.max_entries) { + int nr_cpus; + + nr_cpus = libbpf_num_possible_cpus(); + if (nr_cpus < 0) { + pr_warn("map '%s': failed to determine number of system CPUs: %d\n", + map->name, nr_cpus); + return nr_cpus; + } + pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus); + map->def.max_entries = nr_cpus; + } + + return 0; +} + static int bpf_object__create_maps(struct bpf_object *obj) { @@ -4240,10 +5287,39 @@ bpf_object__create_maps(struct bpf_object *obj) char *cp, errmsg[STRERR_BUFSIZE]; unsigned int i, j; int err; + bool retried; for (i = 0; i < obj->nr_maps; i++) { map = &obj->maps[i]; + /* To support old kernels, we skip creating global data maps + * (.rodata, .data, .kconfig, etc); later on, during program + * loading, if we detect that at least one of the to-be-loaded + * programs is referencing any global data map, we'll error + * out with program name and relocation index logged. + * This approach allows to accommodate Clang emitting + * unnecessary .rodata.str1.1 sections for string literals, + * but also it allows to have CO-RE applications that use + * global variables in some of BPF programs, but not others. + * If those global variable-using programs are not loaded at + * runtime due to bpf_program__set_autoload(prog, false), + * bpf_object loading will succeed just fine even on old + * kernels. + */ + if (bpf_map__is_internal(map) && !kernel_supports(obj, FEAT_GLOBAL_DATA)) + map->autocreate = false; + + if (!map->autocreate) { + pr_debug("map '%s': skipped auto-creating...\n", map->name); + continue; + } + + err = map_set_def_max_entries(map); + if (err) + goto err_out; + + retried = false; +retry: if (map->pin_path) { err = bpf_object__reuse_map(map); if (err) { @@ -4251,13 +5327,19 @@ bpf_object__create_maps(struct bpf_object *obj) map->name); goto err_out; } + if (retried && map->fd < 0) { + pr_warn("map '%s': cannot find pinned map\n", + map->name); + err = -ENOENT; + goto err_out; + } } - if (map->fd >= 0) { + if (map->reused) { pr_debug("map '%s': skipping creation (preset fd=%d)\n", map->name, map->fd); } else { - err = bpf_object__create_map(obj, map); + err = bpf_object__create_map(obj, map, false); if (err) goto err_out; @@ -4266,27 +5348,42 @@ bpf_object__create_maps(struct bpf_object *obj) if (bpf_map__is_internal(map)) { err = bpf_object__populate_internal_map(obj, map); - if (err < 0) { - zclose(map->fd); + if (err < 0) goto err_out; + } + if (map->def.type == BPF_MAP_TYPE_ARENA) { + map->mmaped = mmap((void *)map->map_extra, bpf_map_mmap_sz(map), + PROT_READ | PROT_WRITE, + map->map_extra ? MAP_SHARED | MAP_FIXED : MAP_SHARED, + map->fd, 0); + if (map->mmaped == MAP_FAILED) { + err = -errno; + map->mmaped = NULL; + pr_warn("map '%s': failed to mmap arena: %d\n", + map->name, err); + return err; + } + if (obj->arena_data) { + memcpy(map->mmaped, obj->arena_data, obj->arena_data_sz); + zfree(&obj->arena_data); } } - - if (map->init_slots_sz) { - err = init_map_slots(map); - if (err < 0) { - zclose(map->fd); + if (map->init_slots_sz && map->def.type != BPF_MAP_TYPE_PROG_ARRAY) { + err = init_map_in_map_slots(obj, map); + if (err < 0) goto err_out; - } } } if (map->pin_path && !map->pinned) { err = bpf_map__pin(map, NULL); if (err) { + if (!retried && err == -EEXIST) { + retried = true; + goto retry; + } pr_warn("map '%s': failed to auto-pin at '%s': %d\n", map->name, map->pin_path, err); - zclose(map->fd); goto err_out; } } @@ -4303,279 +5400,6 @@ err_out: return err; } -#define BPF_CORE_SPEC_MAX_LEN 64 - -/* represents BPF CO-RE field or array element accessor */ -struct bpf_core_accessor { - __u32 type_id; /* struct/union type or array element type */ - __u32 idx; /* field index or array index */ - const char *name; /* field name or NULL for array accessor */ -}; - -struct bpf_core_spec { - const struct btf *btf; - /* high-level spec: named fields and array indices only */ - struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN]; - /* original unresolved (no skip_mods_or_typedefs) root type ID */ - __u32 root_type_id; - /* CO-RE relocation kind */ - enum bpf_core_relo_kind relo_kind; - /* high-level spec length */ - int len; - /* raw, low-level spec: 1-to-1 with accessor spec string */ - int raw_spec[BPF_CORE_SPEC_MAX_LEN]; - /* raw spec length */ - int raw_len; - /* field bit offset represented by spec */ - __u32 bit_offset; -}; - -static bool str_is_empty(const char *s) -{ - return !s || !s[0]; -} - -static bool is_flex_arr(const struct btf *btf, - const struct bpf_core_accessor *acc, - const struct btf_array *arr) -{ - const struct btf_type *t; - - /* not a flexible array, if not inside a struct or has non-zero size */ - if (!acc->name || arr->nelems > 0) - return false; - - /* has to be the last member of enclosing struct */ - t = btf__type_by_id(btf, acc->type_id); - return acc->idx == btf_vlen(t) - 1; -} - -static const char *core_relo_kind_str(enum bpf_core_relo_kind kind) -{ - switch (kind) { - case BPF_FIELD_BYTE_OFFSET: return "byte_off"; - case BPF_FIELD_BYTE_SIZE: return "byte_sz"; - case BPF_FIELD_EXISTS: return "field_exists"; - case BPF_FIELD_SIGNED: return "signed"; - case BPF_FIELD_LSHIFT_U64: return "lshift_u64"; - case BPF_FIELD_RSHIFT_U64: return "rshift_u64"; - case BPF_TYPE_ID_LOCAL: return "local_type_id"; - case BPF_TYPE_ID_TARGET: return "target_type_id"; - case BPF_TYPE_EXISTS: return "type_exists"; - case BPF_TYPE_SIZE: return "type_size"; - case BPF_ENUMVAL_EXISTS: return "enumval_exists"; - case BPF_ENUMVAL_VALUE: return "enumval_value"; - default: return "unknown"; - } -} - -static bool core_relo_is_field_based(enum bpf_core_relo_kind kind) -{ - switch (kind) { - case BPF_FIELD_BYTE_OFFSET: - case BPF_FIELD_BYTE_SIZE: - case BPF_FIELD_EXISTS: - case BPF_FIELD_SIGNED: - case BPF_FIELD_LSHIFT_U64: - case BPF_FIELD_RSHIFT_U64: - return true; - default: - return false; - } -} - -static bool core_relo_is_type_based(enum bpf_core_relo_kind kind) -{ - switch (kind) { - case BPF_TYPE_ID_LOCAL: - case BPF_TYPE_ID_TARGET: - case BPF_TYPE_EXISTS: - case BPF_TYPE_SIZE: - return true; - default: - return false; - } -} - -static bool core_relo_is_enumval_based(enum bpf_core_relo_kind kind) -{ - switch (kind) { - case BPF_ENUMVAL_EXISTS: - case BPF_ENUMVAL_VALUE: - return true; - default: - return false; - } -} - -/* - * Turn bpf_core_relo into a low- and high-level spec representation, - * validating correctness along the way, as well as calculating resulting - * field bit offset, specified by accessor string. Low-level spec captures - * every single level of nestedness, including traversing anonymous - * struct/union members. High-level one only captures semantically meaningful - * "turning points": named fields and array indicies. - * E.g., for this case: - * - * struct sample { - * int __unimportant; - * struct { - * int __1; - * int __2; - * int a[7]; - * }; - * }; - * - * struct sample *s = ...; - * - * int x = &s->a[3]; // access string = '0:1:2:3' - * - * Low-level spec has 1:1 mapping with each element of access string (it's - * just a parsed access string representation): [0, 1, 2, 3]. - * - * High-level spec will capture only 3 points: - * - intial zero-index access by pointer (&s->... is the same as &s[0]...); - * - field 'a' access (corresponds to '2' in low-level spec); - * - array element #3 access (corresponds to '3' in low-level spec). - * - * Type-based relocations (TYPE_EXISTS/TYPE_SIZE, - * TYPE_ID_LOCAL/TYPE_ID_TARGET) don't capture any field information. Their - * spec and raw_spec are kept empty. - * - * Enum value-based relocations (ENUMVAL_EXISTS/ENUMVAL_VALUE) use access - * string to specify enumerator's value index that need to be relocated. - */ -static int bpf_core_parse_spec(const struct btf *btf, - __u32 type_id, - const char *spec_str, - enum bpf_core_relo_kind relo_kind, - struct bpf_core_spec *spec) -{ - int access_idx, parsed_len, i; - struct bpf_core_accessor *acc; - const struct btf_type *t; - const char *name; - __u32 id; - __s64 sz; - - if (str_is_empty(spec_str) || *spec_str == ':') - return -EINVAL; - - memset(spec, 0, sizeof(*spec)); - spec->btf = btf; - spec->root_type_id = type_id; - spec->relo_kind = relo_kind; - - /* type-based relocations don't have a field access string */ - if (core_relo_is_type_based(relo_kind)) { - if (strcmp(spec_str, "0")) - return -EINVAL; - return 0; - } - - /* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */ - while (*spec_str) { - if (*spec_str == ':') - ++spec_str; - if (sscanf(spec_str, "%d%n", &access_idx, &parsed_len) != 1) - return -EINVAL; - if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN) - return -E2BIG; - spec_str += parsed_len; - spec->raw_spec[spec->raw_len++] = access_idx; - } - - if (spec->raw_len == 0) - return -EINVAL; - - t = skip_mods_and_typedefs(btf, type_id, &id); - if (!t) - return -EINVAL; - - access_idx = spec->raw_spec[0]; - acc = &spec->spec[0]; - acc->type_id = id; - acc->idx = access_idx; - spec->len++; - - if (core_relo_is_enumval_based(relo_kind)) { - if (!btf_is_enum(t) || spec->raw_len > 1 || access_idx >= btf_vlen(t)) - return -EINVAL; - - /* record enumerator name in a first accessor */ - acc->name = btf__name_by_offset(btf, btf_enum(t)[access_idx].name_off); - return 0; - } - - if (!core_relo_is_field_based(relo_kind)) - return -EINVAL; - - sz = btf__resolve_size(btf, id); - if (sz < 0) - return sz; - spec->bit_offset = access_idx * sz * 8; - - for (i = 1; i < spec->raw_len; i++) { - t = skip_mods_and_typedefs(btf, id, &id); - if (!t) - return -EINVAL; - - access_idx = spec->raw_spec[i]; - acc = &spec->spec[spec->len]; - - if (btf_is_composite(t)) { - const struct btf_member *m; - __u32 bit_offset; - - if (access_idx >= btf_vlen(t)) - return -EINVAL; - - bit_offset = btf_member_bit_offset(t, access_idx); - spec->bit_offset += bit_offset; - - m = btf_members(t) + access_idx; - if (m->name_off) { - name = btf__name_by_offset(btf, m->name_off); - if (str_is_empty(name)) - return -EINVAL; - - acc->type_id = id; - acc->idx = access_idx; - acc->name = name; - spec->len++; - } - - id = m->type; - } else if (btf_is_array(t)) { - const struct btf_array *a = btf_array(t); - bool flex; - - t = skip_mods_and_typedefs(btf, a->type, &id); - if (!t) - return -EINVAL; - - flex = is_flex_arr(btf, acc - 1, a); - if (!flex && access_idx >= a->nelems) - return -EINVAL; - - spec->spec[spec->len].type_id = id; - spec->spec[spec->len].idx = access_idx; - spec->len++; - - sz = btf__resolve_size(btf, id); - if (sz < 0) - return sz; - spec->bit_offset += access_idx * sz * 8; - } else { - pr_warn("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %s\n", - type_id, spec_str, i, id, btf_kind_str(t)); - return -EINVAL; - } - } - - return 0; -} - static bool bpf_core_is_flavor_sep(const char *s) { /* check X___Y name pattern, where X and Y are not underscores */ @@ -4588,7 +5412,7 @@ static bool bpf_core_is_flavor_sep(const char *s) * before last triple underscore. Struct name part after last triple * underscore is ignored by BPF CO-RE relocation during relocation matching. */ -static size_t bpf_core_essential_name_len(const char *name) +size_t bpf_core_essential_name_len(const char *name) { size_t n = strlen(name); int i; @@ -4600,46 +5424,35 @@ static size_t bpf_core_essential_name_len(const char *name) return n; } -/* dynamically sized list of type IDs */ -struct ids_vec { - __u32 *data; - int len; -}; - -static void bpf_core_free_cands(struct ids_vec *cand_ids) +void bpf_core_free_cands(struct bpf_core_cand_list *cands) { - free(cand_ids->data); - free(cand_ids); + if (!cands) + return; + + free(cands->cands); + free(cands); } -static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf, - __u32 local_type_id, - const struct btf *targ_btf) +int bpf_core_add_cands(struct bpf_core_cand *local_cand, + size_t local_essent_len, + const struct btf *targ_btf, + const char *targ_btf_name, + int targ_start_id, + struct bpf_core_cand_list *cands) { - size_t local_essent_len, targ_essent_len; - const char *local_name, *targ_name; + struct bpf_core_cand *new_cands, *cand; const struct btf_type *t, *local_t; - struct ids_vec *cand_ids; - __u32 *new_ids; - int i, err, n; - - local_t = btf__type_by_id(local_btf, local_type_id); - if (!local_t) - return ERR_PTR(-EINVAL); - - local_name = btf__name_by_offset(local_btf, local_t->name_off); - if (str_is_empty(local_name)) - return ERR_PTR(-EINVAL); - local_essent_len = bpf_core_essential_name_len(local_name); + const char *targ_name, *local_name; + size_t targ_essent_len; + int n, i; - cand_ids = calloc(1, sizeof(*cand_ids)); - if (!cand_ids) - return ERR_PTR(-ENOMEM); + local_t = btf__type_by_id(local_cand->btf, local_cand->id); + local_name = btf__str_by_offset(local_cand->btf, local_t->name_off); - n = btf__get_nr_types(targ_btf); - for (i = 1; i <= n; i++) { + n = btf__type_cnt(targ_btf); + for (i = targ_start_id; i < n; i++) { t = btf__type_by_id(targ_btf, i); - if (btf_kind(t) != btf_kind(local_t)) + if (!btf_kind_core_compat(t, local_t)) continue; targ_name = btf__name_by_offset(targ_btf, t->name_off); @@ -4650,1031 +5463,275 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf, if (targ_essent_len != local_essent_len) continue; - if (strncmp(local_name, targ_name, local_essent_len) == 0) { - pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s\n", - local_type_id, btf_kind_str(local_t), - local_name, i, btf_kind_str(t), targ_name); - new_ids = libbpf_reallocarray(cand_ids->data, - cand_ids->len + 1, - sizeof(*cand_ids->data)); - if (!new_ids) { - err = -ENOMEM; - goto err_out; - } - cand_ids->data = new_ids; - cand_ids->data[cand_ids->len++] = i; - } - } - return cand_ids; -err_out: - bpf_core_free_cands(cand_ids); - return ERR_PTR(err); -} - -/* Check two types for compatibility for the purpose of field access - * relocation. const/volatile/restrict and typedefs are skipped to ensure we - * are relocating semantically compatible entities: - * - any two STRUCTs/UNIONs are compatible and can be mixed; - * - any two FWDs are compatible, if their names match (modulo flavor suffix); - * - any two PTRs are always compatible; - * - for ENUMs, names should be the same (ignoring flavor suffix) or at - * least one of enums should be anonymous; - * - for ENUMs, check sizes, names are ignored; - * - for INT, size and signedness are ignored; - * - for ARRAY, dimensionality is ignored, element types are checked for - * compatibility recursively; - * - everything else shouldn't be ever a target of relocation. - * These rules are not set in stone and probably will be adjusted as we get - * more experience with using BPF CO-RE relocations. - */ -static int bpf_core_fields_are_compat(const struct btf *local_btf, - __u32 local_id, - const struct btf *targ_btf, - __u32 targ_id) -{ - const struct btf_type *local_type, *targ_type; - -recur: - local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id); - targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id); - if (!local_type || !targ_type) - return -EINVAL; - - if (btf_is_composite(local_type) && btf_is_composite(targ_type)) - return 1; - if (btf_kind(local_type) != btf_kind(targ_type)) - return 0; - - switch (btf_kind(local_type)) { - case BTF_KIND_PTR: - return 1; - case BTF_KIND_FWD: - case BTF_KIND_ENUM: { - const char *local_name, *targ_name; - size_t local_len, targ_len; - - local_name = btf__name_by_offset(local_btf, - local_type->name_off); - targ_name = btf__name_by_offset(targ_btf, targ_type->name_off); - local_len = bpf_core_essential_name_len(local_name); - targ_len = bpf_core_essential_name_len(targ_name); - /* one of them is anonymous or both w/ same flavor-less names */ - return local_len == 0 || targ_len == 0 || - (local_len == targ_len && - strncmp(local_name, targ_name, local_len) == 0); - } - case BTF_KIND_INT: - /* just reject deprecated bitfield-like integers; all other - * integers are by default compatible between each other - */ - return btf_int_offset(local_type) == 0 && - btf_int_offset(targ_type) == 0; - case BTF_KIND_ARRAY: - local_id = btf_array(local_type)->type; - targ_id = btf_array(targ_type)->type; - goto recur; - default: - pr_warn("unexpected kind %d relocated, local [%d], target [%d]\n", - btf_kind(local_type), local_id, targ_id); - return 0; - } -} - -/* - * Given single high-level named field accessor in local type, find - * corresponding high-level accessor for a target type. Along the way, - * maintain low-level spec for target as well. Also keep updating target - * bit offset. - * - * Searching is performed through recursive exhaustive enumeration of all - * fields of a struct/union. If there are any anonymous (embedded) - * structs/unions, they are recursively searched as well. If field with - * desired name is found, check compatibility between local and target types, - * before returning result. - * - * 1 is returned, if field is found. - * 0 is returned if no compatible field is found. - * <0 is returned on error. - */ -static int bpf_core_match_member(const struct btf *local_btf, - const struct bpf_core_accessor *local_acc, - const struct btf *targ_btf, - __u32 targ_id, - struct bpf_core_spec *spec, - __u32 *next_targ_id) -{ - const struct btf_type *local_type, *targ_type; - const struct btf_member *local_member, *m; - const char *local_name, *targ_name; - __u32 local_id; - int i, n, found; - - targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id); - if (!targ_type) - return -EINVAL; - if (!btf_is_composite(targ_type)) - return 0; - - local_id = local_acc->type_id; - local_type = btf__type_by_id(local_btf, local_id); - local_member = btf_members(local_type) + local_acc->idx; - local_name = btf__name_by_offset(local_btf, local_member->name_off); - - n = btf_vlen(targ_type); - m = btf_members(targ_type); - for (i = 0; i < n; i++, m++) { - __u32 bit_offset; + if (strncmp(local_name, targ_name, local_essent_len) != 0) + continue; - bit_offset = btf_member_bit_offset(targ_type, i); + pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s in [%s]\n", + local_cand->id, btf_kind_str(local_t), + local_name, i, btf_kind_str(t), targ_name, + targ_btf_name); + new_cands = libbpf_reallocarray(cands->cands, cands->len + 1, + sizeof(*cands->cands)); + if (!new_cands) + return -ENOMEM; - /* too deep struct/union/array nesting */ - if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN) - return -E2BIG; + cand = &new_cands[cands->len]; + cand->btf = targ_btf; + cand->id = i; - /* speculate this member will be the good one */ - spec->bit_offset += bit_offset; - spec->raw_spec[spec->raw_len++] = i; - - targ_name = btf__name_by_offset(targ_btf, m->name_off); - if (str_is_empty(targ_name)) { - /* embedded struct/union, we need to go deeper */ - found = bpf_core_match_member(local_btf, local_acc, - targ_btf, m->type, - spec, next_targ_id); - if (found) /* either found or error */ - return found; - } else if (strcmp(local_name, targ_name) == 0) { - /* matching named field */ - struct bpf_core_accessor *targ_acc; - - targ_acc = &spec->spec[spec->len++]; - targ_acc->type_id = targ_id; - targ_acc->idx = i; - targ_acc->name = targ_name; - - *next_targ_id = m->type; - found = bpf_core_fields_are_compat(local_btf, - local_member->type, - targ_btf, m->type); - if (!found) - spec->len--; /* pop accessor */ - return found; - } - /* member turned out not to be what we looked for */ - spec->bit_offset -= bit_offset; - spec->raw_len--; + cands->cands = new_cands; + cands->len++; } - return 0; } -/* Check local and target types for compatibility. This check is used for - * type-based CO-RE relocations and follow slightly different rules than - * field-based relocations. This function assumes that root types were already - * checked for name match. Beyond that initial root-level name check, names - * are completely ignored. Compatibility rules are as follows: - * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but - * kind should match for local and target types (i.e., STRUCT is not - * compatible with UNION); - * - for ENUMs, the size is ignored; - * - for INT, size and signedness are ignored; - * - for ARRAY, dimensionality is ignored, element types are checked for - * compatibility recursively; - * - CONST/VOLATILE/RESTRICT modifiers are ignored; - * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible; - * - FUNC_PROTOs are compatible if they have compatible signature: same - * number of input args and compatible return and argument types. - * These rules are not set in stone and probably will be adjusted as we get - * more experience with using BPF CO-RE relocations. - */ -static int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id, - const struct btf *targ_btf, __u32 targ_id) +static int load_module_btfs(struct bpf_object *obj) { - const struct btf_type *local_type, *targ_type; - int depth = 32; /* max recursion depth */ + struct bpf_btf_info info; + struct module_btf *mod_btf; + struct btf *btf; + char name[64]; + __u32 id = 0, len; + int err, fd; - /* caller made sure that names match (ignoring flavor suffix) */ - local_type = btf__type_by_id(local_btf, local_id); - targ_type = btf__type_by_id(targ_btf, targ_id); - if (btf_kind(local_type) != btf_kind(targ_type)) + if (obj->btf_modules_loaded) return 0; -recur: - depth--; - if (depth < 0) - return -EINVAL; - - local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id); - targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id); - if (!local_type || !targ_type) - return -EINVAL; - - if (btf_kind(local_type) != btf_kind(targ_type)) + if (obj->gen_loader) return 0; - switch (btf_kind(local_type)) { - case BTF_KIND_UNKN: - case BTF_KIND_STRUCT: - case BTF_KIND_UNION: - case BTF_KIND_ENUM: - case BTF_KIND_FWD: - return 1; - case BTF_KIND_INT: - /* just reject deprecated bitfield-like integers; all other - * integers are by default compatible between each other - */ - return btf_int_offset(local_type) == 0 && btf_int_offset(targ_type) == 0; - case BTF_KIND_PTR: - local_id = local_type->type; - targ_id = targ_type->type; - goto recur; - case BTF_KIND_ARRAY: - local_id = btf_array(local_type)->type; - targ_id = btf_array(targ_type)->type; - goto recur; - case BTF_KIND_FUNC_PROTO: { - struct btf_param *local_p = btf_params(local_type); - struct btf_param *targ_p = btf_params(targ_type); - __u16 local_vlen = btf_vlen(local_type); - __u16 targ_vlen = btf_vlen(targ_type); - int i, err; - - if (local_vlen != targ_vlen) - return 0; - - for (i = 0; i < local_vlen; i++, local_p++, targ_p++) { - skip_mods_and_typedefs(local_btf, local_p->type, &local_id); - skip_mods_and_typedefs(targ_btf, targ_p->type, &targ_id); - err = bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id); - if (err <= 0) - return err; - } + /* don't do this again, even if we find no module BTFs */ + obj->btf_modules_loaded = true; - /* tail recurse for return type check */ - skip_mods_and_typedefs(local_btf, local_type->type, &local_id); - skip_mods_and_typedefs(targ_btf, targ_type->type, &targ_id); - goto recur; - } - default: - pr_warn("unexpected kind %s relocated, local [%d], target [%d]\n", - btf_kind_str(local_type), local_id, targ_id); + /* kernel too old to support module BTFs */ + if (!kernel_supports(obj, FEAT_MODULE_BTF)) return 0; - } -} - -/* - * Try to match local spec to a target type and, if successful, produce full - * target spec (high-level, low-level + bit offset). - */ -static int bpf_core_spec_match(struct bpf_core_spec *local_spec, - const struct btf *targ_btf, __u32 targ_id, - struct bpf_core_spec *targ_spec) -{ - const struct btf_type *targ_type; - const struct bpf_core_accessor *local_acc; - struct bpf_core_accessor *targ_acc; - int i, sz, matched; - - memset(targ_spec, 0, sizeof(*targ_spec)); - targ_spec->btf = targ_btf; - targ_spec->root_type_id = targ_id; - targ_spec->relo_kind = local_spec->relo_kind; - - if (core_relo_is_type_based(local_spec->relo_kind)) { - return bpf_core_types_are_compat(local_spec->btf, - local_spec->root_type_id, - targ_btf, targ_id); - } - - local_acc = &local_spec->spec[0]; - targ_acc = &targ_spec->spec[0]; - - if (core_relo_is_enumval_based(local_spec->relo_kind)) { - size_t local_essent_len, targ_essent_len; - const struct btf_enum *e; - const char *targ_name; - /* has to resolve to an enum */ - targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id, &targ_id); - if (!btf_is_enum(targ_type)) + while (true) { + err = bpf_btf_get_next_id(id, &id); + if (err && errno == ENOENT) + return 0; + if (err && errno == EPERM) { + pr_debug("skipping module BTFs loading, missing privileges\n"); return 0; - - local_essent_len = bpf_core_essential_name_len(local_acc->name); - - for (i = 0, e = btf_enum(targ_type); i < btf_vlen(targ_type); i++, e++) { - targ_name = btf__name_by_offset(targ_spec->btf, e->name_off); - targ_essent_len = bpf_core_essential_name_len(targ_name); - if (targ_essent_len != local_essent_len) - continue; - if (strncmp(local_acc->name, targ_name, local_essent_len) == 0) { - targ_acc->type_id = targ_id; - targ_acc->idx = i; - targ_acc->name = targ_name; - targ_spec->len++; - targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx; - targ_spec->raw_len++; - return 1; - } } - return 0; - } - - if (!core_relo_is_field_based(local_spec->relo_kind)) - return -EINVAL; - - for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) { - targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id, - &targ_id); - if (!targ_type) - return -EINVAL; - - if (local_acc->name) { - matched = bpf_core_match_member(local_spec->btf, - local_acc, - targ_btf, targ_id, - targ_spec, &targ_id); - if (matched <= 0) - return matched; - } else { - /* for i=0, targ_id is already treated as array element - * type (because it's the original struct), for others - * we should find array element type first - */ - if (i > 0) { - const struct btf_array *a; - bool flex; - - if (!btf_is_array(targ_type)) - return 0; - - a = btf_array(targ_type); - flex = is_flex_arr(targ_btf, targ_acc - 1, a); - if (!flex && local_acc->idx >= a->nelems) - return 0; - if (!skip_mods_and_typedefs(targ_btf, a->type, - &targ_id)) - return -EINVAL; - } - - /* too deep struct/union/array nesting */ - if (targ_spec->raw_len == BPF_CORE_SPEC_MAX_LEN) - return -E2BIG; - - targ_acc->type_id = targ_id; - targ_acc->idx = local_acc->idx; - targ_acc->name = NULL; - targ_spec->len++; - targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx; - targ_spec->raw_len++; - - sz = btf__resolve_size(targ_btf, targ_id); - if (sz < 0) - return sz; - targ_spec->bit_offset += local_acc->idx * sz * 8; + if (err) { + err = -errno; + pr_warn("failed to iterate BTF objects: %d\n", err); + return err; } - } - - return 1; -} - -static int bpf_core_calc_field_relo(const struct bpf_program *prog, - const struct bpf_core_relo *relo, - const struct bpf_core_spec *spec, - __u32 *val, __u32 *field_sz, __u32 *type_id, - bool *validate) -{ - const struct bpf_core_accessor *acc; - const struct btf_type *t; - __u32 byte_off, byte_sz, bit_off, bit_sz, field_type_id; - const struct btf_member *m; - const struct btf_type *mt; - bool bitfield; - __s64 sz; - *field_sz = 0; - - if (relo->kind == BPF_FIELD_EXISTS) { - *val = spec ? 1 : 0; - return 0; - } + fd = bpf_btf_get_fd_by_id(id); + if (fd < 0) { + if (errno == ENOENT) + continue; /* expected race: BTF was unloaded */ + err = -errno; + pr_warn("failed to get BTF object #%d FD: %d\n", id, err); + return err; + } - if (!spec) - return -EUCLEAN; /* request instruction poisoning */ + len = sizeof(info); + memset(&info, 0, sizeof(info)); + info.name = ptr_to_u64(name); + info.name_len = sizeof(name); - acc = &spec->spec[spec->len - 1]; - t = btf__type_by_id(spec->btf, acc->type_id); + err = bpf_btf_get_info_by_fd(fd, &info, &len); + if (err) { + err = -errno; + pr_warn("failed to get BTF object #%d info: %d\n", id, err); + goto err_out; + } - /* a[n] accessor needs special handling */ - if (!acc->name) { - if (relo->kind == BPF_FIELD_BYTE_OFFSET) { - *val = spec->bit_offset / 8; - /* remember field size for load/store mem size */ - sz = btf__resolve_size(spec->btf, acc->type_id); - if (sz < 0) - return -EINVAL; - *field_sz = sz; - *type_id = acc->type_id; - } else if (relo->kind == BPF_FIELD_BYTE_SIZE) { - sz = btf__resolve_size(spec->btf, acc->type_id); - if (sz < 0) - return -EINVAL; - *val = sz; - } else { - pr_warn("prog '%s': relo %d at insn #%d can't be applied to array access\n", - prog->name, relo->kind, relo->insn_off / 8); - return -EINVAL; + /* ignore non-module BTFs */ + if (!info.kernel_btf || strcmp(name, "vmlinux") == 0) { + close(fd); + continue; } - if (validate) - *validate = true; - return 0; - } - m = btf_members(t) + acc->idx; - mt = skip_mods_and_typedefs(spec->btf, m->type, &field_type_id); - bit_off = spec->bit_offset; - bit_sz = btf_member_bitfield_size(t, acc->idx); - - bitfield = bit_sz > 0; - if (bitfield) { - byte_sz = mt->size; - byte_off = bit_off / 8 / byte_sz * byte_sz; - /* figure out smallest int size necessary for bitfield load */ - while (bit_off + bit_sz - byte_off * 8 > byte_sz * 8) { - if (byte_sz >= 8) { - /* bitfield can't be read with 64-bit read */ - pr_warn("prog '%s': relo %d at insn #%d can't be satisfied for bitfield\n", - prog->name, relo->kind, relo->insn_off / 8); - return -E2BIG; - } - byte_sz *= 2; - byte_off = bit_off / 8 / byte_sz * byte_sz; + btf = btf_get_from_fd(fd, obj->btf_vmlinux); + err = libbpf_get_error(btf); + if (err) { + pr_warn("failed to load module [%s]'s BTF object #%d: %d\n", + name, id, err); + goto err_out; } - } else { - sz = btf__resolve_size(spec->btf, field_type_id); - if (sz < 0) - return -EINVAL; - byte_sz = sz; - byte_off = spec->bit_offset / 8; - bit_sz = byte_sz * 8; - } - /* for bitfields, all the relocatable aspects are ambiguous and we - * might disagree with compiler, so turn off validation of expected - * value, except for signedness - */ - if (validate) - *validate = !bitfield; + err = libbpf_ensure_mem((void **)&obj->btf_modules, &obj->btf_module_cap, + sizeof(*obj->btf_modules), obj->btf_module_cnt + 1); + if (err) + goto err_out; - switch (relo->kind) { - case BPF_FIELD_BYTE_OFFSET: - *val = byte_off; - if (!bitfield) { - *field_sz = byte_sz; - *type_id = field_type_id; + mod_btf = &obj->btf_modules[obj->btf_module_cnt++]; + + mod_btf->btf = btf; + mod_btf->id = id; + mod_btf->fd = fd; + mod_btf->name = strdup(name); + if (!mod_btf->name) { + err = -ENOMEM; + goto err_out; } - break; - case BPF_FIELD_BYTE_SIZE: - *val = byte_sz; - break; - case BPF_FIELD_SIGNED: - /* enums will be assumed unsigned */ - *val = btf_is_enum(mt) || - (btf_int_encoding(mt) & BTF_INT_SIGNED); - if (validate) - *validate = true; /* signedness is never ambiguous */ - break; - case BPF_FIELD_LSHIFT_U64: -#if __BYTE_ORDER == __LITTLE_ENDIAN - *val = 64 - (bit_off + bit_sz - byte_off * 8); -#else - *val = (8 - byte_sz) * 8 + (bit_off - byte_off * 8); -#endif - break; - case BPF_FIELD_RSHIFT_U64: - *val = 64 - bit_sz; - if (validate) - *validate = true; /* right shift is never ambiguous */ - break; - case BPF_FIELD_EXISTS: - default: - return -EOPNOTSUPP; + continue; + +err_out: + close(fd); + return err; } return 0; } -static int bpf_core_calc_type_relo(const struct bpf_core_relo *relo, - const struct bpf_core_spec *spec, - __u32 *val) +static struct bpf_core_cand_list * +bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id) { - __s64 sz; - - /* type-based relos return zero when target type is not found */ - if (!spec) { - *val = 0; - return 0; - } + struct bpf_core_cand local_cand = {}; + struct bpf_core_cand_list *cands; + const struct btf *main_btf; + const struct btf_type *local_t; + const char *local_name; + size_t local_essent_len; + int err, i; - switch (relo->kind) { - case BPF_TYPE_ID_TARGET: - *val = spec->root_type_id; - break; - case BPF_TYPE_EXISTS: - *val = 1; - break; - case BPF_TYPE_SIZE: - sz = btf__resolve_size(spec->btf, spec->root_type_id); - if (sz < 0) - return -EINVAL; - *val = sz; - break; - case BPF_TYPE_ID_LOCAL: - /* BPF_TYPE_ID_LOCAL is handled specially and shouldn't get here */ - default: - return -EOPNOTSUPP; - } + local_cand.btf = local_btf; + local_cand.id = local_type_id; + local_t = btf__type_by_id(local_btf, local_type_id); + if (!local_t) + return ERR_PTR(-EINVAL); - return 0; -} + local_name = btf__name_by_offset(local_btf, local_t->name_off); + if (str_is_empty(local_name)) + return ERR_PTR(-EINVAL); + local_essent_len = bpf_core_essential_name_len(local_name); -static int bpf_core_calc_enumval_relo(const struct bpf_core_relo *relo, - const struct bpf_core_spec *spec, - __u32 *val) -{ - const struct btf_type *t; - const struct btf_enum *e; + cands = calloc(1, sizeof(*cands)); + if (!cands) + return ERR_PTR(-ENOMEM); - switch (relo->kind) { - case BPF_ENUMVAL_EXISTS: - *val = spec ? 1 : 0; - break; - case BPF_ENUMVAL_VALUE: - if (!spec) - return -EUCLEAN; /* request instruction poisoning */ - t = btf__type_by_id(spec->btf, spec->spec[0].type_id); - e = btf_enum(t) + spec->spec[0].idx; - *val = e->val; - break; - default: - return -EOPNOTSUPP; - } + /* Attempt to find target candidates in vmlinux BTF first */ + main_btf = obj->btf_vmlinux_override ?: obj->btf_vmlinux; + err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf, "vmlinux", 1, cands); + if (err) + goto err_out; - return 0; -} + /* if vmlinux BTF has any candidate, don't got for module BTFs */ + if (cands->len) + return cands; -struct bpf_core_relo_res -{ - /* expected value in the instruction, unless validate == false */ - __u32 orig_val; - /* new value that needs to be patched up to */ - __u32 new_val; - /* relocation unsuccessful, poison instruction, but don't fail load */ - bool poison; - /* some relocations can't be validated against orig_val */ - bool validate; - /* for field byte offset relocations or the forms: - * *(T *)(rX + <off>) = rY - * rX = *(T *)(rY + <off>), - * we remember original and resolved field size to adjust direct - * memory loads of pointers and integers; this is necessary for 32-bit - * host kernel architectures, but also allows to automatically - * relocate fields that were resized from, e.g., u32 to u64, etc. - */ - bool fail_memsz_adjust; - __u32 orig_sz; - __u32 orig_type_id; - __u32 new_sz; - __u32 new_type_id; -}; + /* if vmlinux BTF was overridden, don't attempt to load module BTFs */ + if (obj->btf_vmlinux_override) + return cands; -/* Calculate original and target relocation values, given local and target - * specs and relocation kind. These values are calculated for each candidate. - * If there are multiple candidates, resulting values should all be consistent - * with each other. Otherwise, libbpf will refuse to proceed due to ambiguity. - * If instruction has to be poisoned, *poison will be set to true. - */ -static int bpf_core_calc_relo(const struct bpf_program *prog, - const struct bpf_core_relo *relo, - int relo_idx, - const struct bpf_core_spec *local_spec, - const struct bpf_core_spec *targ_spec, - struct bpf_core_relo_res *res) -{ - int err = -EOPNOTSUPP; - - res->orig_val = 0; - res->new_val = 0; - res->poison = false; - res->validate = true; - res->fail_memsz_adjust = false; - res->orig_sz = res->new_sz = 0; - res->orig_type_id = res->new_type_id = 0; - - if (core_relo_is_field_based(relo->kind)) { - err = bpf_core_calc_field_relo(prog, relo, local_spec, - &res->orig_val, &res->orig_sz, - &res->orig_type_id, &res->validate); - err = err ?: bpf_core_calc_field_relo(prog, relo, targ_spec, - &res->new_val, &res->new_sz, - &res->new_type_id, NULL); + /* now look through module BTFs, trying to still find candidates */ + err = load_module_btfs(obj); + if (err) + goto err_out; + + for (i = 0; i < obj->btf_module_cnt; i++) { + err = bpf_core_add_cands(&local_cand, local_essent_len, + obj->btf_modules[i].btf, + obj->btf_modules[i].name, + btf__type_cnt(obj->btf_vmlinux), + cands); if (err) - goto done; - /* Validate if it's safe to adjust load/store memory size. - * Adjustments are performed only if original and new memory - * sizes differ. - */ - res->fail_memsz_adjust = false; - if (res->orig_sz != res->new_sz) { - const struct btf_type *orig_t, *new_t; - - orig_t = btf__type_by_id(local_spec->btf, res->orig_type_id); - new_t = btf__type_by_id(targ_spec->btf, res->new_type_id); - - /* There are two use cases in which it's safe to - * adjust load/store's mem size: - * - reading a 32-bit kernel pointer, while on BPF - * size pointers are always 64-bit; in this case - * it's safe to "downsize" instruction size due to - * pointer being treated as unsigned integer with - * zero-extended upper 32-bits; - * - reading unsigned integers, again due to - * zero-extension is preserving the value correctly. - * - * In all other cases it's incorrect to attempt to - * load/store field because read value will be - * incorrect, so we poison relocated instruction. - */ - if (btf_is_ptr(orig_t) && btf_is_ptr(new_t)) - goto done; - if (btf_is_int(orig_t) && btf_is_int(new_t) && - btf_int_encoding(orig_t) != BTF_INT_SIGNED && - btf_int_encoding(new_t) != BTF_INT_SIGNED) - goto done; - - /* mark as invalid mem size adjustment, but this will - * only be checked for LDX/STX/ST insns - */ - res->fail_memsz_adjust = true; - } - } else if (core_relo_is_type_based(relo->kind)) { - err = bpf_core_calc_type_relo(relo, local_spec, &res->orig_val); - err = err ?: bpf_core_calc_type_relo(relo, targ_spec, &res->new_val); - } else if (core_relo_is_enumval_based(relo->kind)) { - err = bpf_core_calc_enumval_relo(relo, local_spec, &res->orig_val); - err = err ?: bpf_core_calc_enumval_relo(relo, targ_spec, &res->new_val); - } - -done: - if (err == -EUCLEAN) { - /* EUCLEAN is used to signal instruction poisoning request */ - res->poison = true; - err = 0; - } else if (err == -EOPNOTSUPP) { - /* EOPNOTSUPP means unknown/unsupported relocation */ - pr_warn("prog '%s': relo #%d: unrecognized CO-RE relocation %s (%d) at insn #%d\n", - prog->name, relo_idx, core_relo_kind_str(relo->kind), - relo->kind, relo->insn_off / 8); + goto err_out; } - return err; + return cands; +err_out: + bpf_core_free_cands(cands); + return ERR_PTR(err); } -/* - * Turn instruction for which CO_RE relocation failed into invalid one with - * distinct signature. +/* Check local and target types for compatibility. This check is used for + * type-based CO-RE relocations and follow slightly different rules than + * field-based relocations. This function assumes that root types were already + * checked for name match. Beyond that initial root-level name check, names + * are completely ignored. Compatibility rules are as follows: + * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but + * kind should match for local and target types (i.e., STRUCT is not + * compatible with UNION); + * - for ENUMs, the size is ignored; + * - for INT, size and signedness are ignored; + * - for ARRAY, dimensionality is ignored, element types are checked for + * compatibility recursively; + * - CONST/VOLATILE/RESTRICT modifiers are ignored; + * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible; + * - FUNC_PROTOs are compatible if they have compatible signature: same + * number of input args and compatible return and argument types. + * These rules are not set in stone and probably will be adjusted as we get + * more experience with using BPF CO-RE relocations. */ -static void bpf_core_poison_insn(struct bpf_program *prog, int relo_idx, - int insn_idx, struct bpf_insn *insn) +int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id, + const struct btf *targ_btf, __u32 targ_id) { - pr_debug("prog '%s': relo #%d: substituting insn #%d w/ invalid insn\n", - prog->name, relo_idx, insn_idx); - insn->code = BPF_JMP | BPF_CALL; - insn->dst_reg = 0; - insn->src_reg = 0; - insn->off = 0; - /* if this instruction is reachable (not a dead code), - * verifier will complain with the following message: - * invalid func unknown#195896080 - */ - insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */ + return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id, 32); } -static bool is_ldimm64(struct bpf_insn *insn) +int bpf_core_types_match(const struct btf *local_btf, __u32 local_id, + const struct btf *targ_btf, __u32 targ_id) { - return insn->code == (BPF_LD | BPF_IMM | BPF_DW); + return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false, 32); } -static int insn_bpf_size_to_bytes(struct bpf_insn *insn) +static size_t bpf_core_hash_fn(const long key, void *ctx) { - switch (BPF_SIZE(insn->code)) { - case BPF_DW: return 8; - case BPF_W: return 4; - case BPF_H: return 2; - case BPF_B: return 1; - default: return -1; - } + return key; } -static int insn_bytes_to_bpf_size(__u32 sz) +static bool bpf_core_equal_fn(const long k1, const long k2, void *ctx) { - switch (sz) { - case 8: return BPF_DW; - case 4: return BPF_W; - case 2: return BPF_H; - case 1: return BPF_B; - default: return -1; - } + return k1 == k2; } -/* - * Patch relocatable BPF instruction. - * - * Patched value is determined by relocation kind and target specification. - * For existence relocations target spec will be NULL if field/type is not found. - * Expected insn->imm value is determined using relocation kind and local - * spec, and is checked before patching instruction. If actual insn->imm value - * is wrong, bail out with error. - * - * Currently supported classes of BPF instruction are: - * 1. rX = <imm> (assignment with immediate operand); - * 2. rX += <imm> (arithmetic operations with immediate operand); - * 3. rX = <imm64> (load with 64-bit immediate value); - * 4. rX = *(T *)(rY + <off>), where T is one of {u8, u16, u32, u64}; - * 5. *(T *)(rX + <off>) = rY, where T is one of {u8, u16, u32, u64}; - * 6. *(T *)(rX + <off>) = <imm>, where T is one of {u8, u16, u32, u64}. - */ -static int bpf_core_patch_insn(struct bpf_program *prog, - const struct bpf_core_relo *relo, - int relo_idx, - const struct bpf_core_relo_res *res) +static int record_relo_core(struct bpf_program *prog, + const struct bpf_core_relo *core_relo, int insn_idx) { - __u32 orig_val, new_val; - struct bpf_insn *insn; - int insn_idx; - __u8 class; - - if (relo->insn_off % BPF_INSN_SZ) - return -EINVAL; - insn_idx = relo->insn_off / BPF_INSN_SZ; - /* adjust insn_idx from section frame of reference to the local - * program's frame of reference; (sub-)program code is not yet - * relocated, so it's enough to just subtract in-section offset - */ - insn_idx = insn_idx - prog->sec_insn_off; - insn = &prog->insns[insn_idx]; - class = BPF_CLASS(insn->code); - - if (res->poison) { -poison: - /* poison second part of ldimm64 to avoid confusing error from - * verifier about "unknown opcode 00" - */ - if (is_ldimm64(insn)) - bpf_core_poison_insn(prog, relo_idx, insn_idx + 1, insn + 1); - bpf_core_poison_insn(prog, relo_idx, insn_idx, insn); - return 0; - } - - orig_val = res->orig_val; - new_val = res->new_val; - - switch (class) { - case BPF_ALU: - case BPF_ALU64: - if (BPF_SRC(insn->code) != BPF_K) - return -EINVAL; - if (res->validate && insn->imm != orig_val) { - pr_warn("prog '%s': relo #%d: unexpected insn #%d (ALU/ALU64) value: got %u, exp %u -> %u\n", - prog->name, relo_idx, - insn_idx, insn->imm, orig_val, new_val); - return -EINVAL; - } - orig_val = insn->imm; - insn->imm = new_val; - pr_debug("prog '%s': relo #%d: patched insn #%d (ALU/ALU64) imm %u -> %u\n", - prog->name, relo_idx, insn_idx, - orig_val, new_val); - break; - case BPF_LDX: - case BPF_ST: - case BPF_STX: - if (res->validate && insn->off != orig_val) { - pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDX/ST/STX) value: got %u, exp %u -> %u\n", - prog->name, relo_idx, insn_idx, insn->off, orig_val, new_val); - return -EINVAL; - } - if (new_val > SHRT_MAX) { - pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) value too big: %u\n", - prog->name, relo_idx, insn_idx, new_val); - return -ERANGE; - } - if (res->fail_memsz_adjust) { - pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) accesses field incorrectly. " - "Make sure you are accessing pointers, unsigned integers, or fields of matching type and size.\n", - prog->name, relo_idx, insn_idx); - goto poison; - } - - orig_val = insn->off; - insn->off = new_val; - pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) off %u -> %u\n", - prog->name, relo_idx, insn_idx, orig_val, new_val); - - if (res->new_sz != res->orig_sz) { - int insn_bytes_sz, insn_bpf_sz; - - insn_bytes_sz = insn_bpf_size_to_bytes(insn); - if (insn_bytes_sz != res->orig_sz) { - pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) unexpected mem size: got %d, exp %u\n", - prog->name, relo_idx, insn_idx, insn_bytes_sz, res->orig_sz); - return -EINVAL; - } - - insn_bpf_sz = insn_bytes_to_bpf_size(res->new_sz); - if (insn_bpf_sz < 0) { - pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) invalid new mem size: %u\n", - prog->name, relo_idx, insn_idx, res->new_sz); - return -EINVAL; - } - - insn->code = BPF_MODE(insn->code) | insn_bpf_sz | BPF_CLASS(insn->code); - pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) mem_sz %u -> %u\n", - prog->name, relo_idx, insn_idx, res->orig_sz, res->new_sz); - } - break; - case BPF_LD: { - __u64 imm; - - if (!is_ldimm64(insn) || - insn[0].src_reg != 0 || insn[0].off != 0 || - insn_idx + 1 >= prog->insns_cnt || - insn[1].code != 0 || insn[1].dst_reg != 0 || - insn[1].src_reg != 0 || insn[1].off != 0) { - pr_warn("prog '%s': relo #%d: insn #%d (LDIMM64) has unexpected form\n", - prog->name, relo_idx, insn_idx); - return -EINVAL; - } - - imm = insn[0].imm + ((__u64)insn[1].imm << 32); - if (res->validate && imm != orig_val) { - pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDIMM64) value: got %llu, exp %u -> %u\n", - prog->name, relo_idx, - insn_idx, (unsigned long long)imm, - orig_val, new_val); - return -EINVAL; - } - - insn[0].imm = new_val; - insn[1].imm = 0; /* currently only 32-bit values are supported */ - pr_debug("prog '%s': relo #%d: patched insn #%d (LDIMM64) imm64 %llu -> %u\n", - prog->name, relo_idx, insn_idx, - (unsigned long long)imm, new_val); - break; - } - default: - pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:0x%x, src:0x%x, dst:0x%x, off:0x%x, imm:0x%x\n", - prog->name, relo_idx, insn_idx, insn->code, - insn->src_reg, insn->dst_reg, insn->off, insn->imm); - return -EINVAL; - } + struct reloc_desc *relos, *relo; + relos = libbpf_reallocarray(prog->reloc_desc, + prog->nr_reloc + 1, sizeof(*relos)); + if (!relos) + return -ENOMEM; + relo = &relos[prog->nr_reloc]; + relo->type = RELO_CORE; + relo->insn_idx = insn_idx; + relo->core_relo = core_relo; + prog->reloc_desc = relos; + prog->nr_reloc++; return 0; } -/* Output spec definition in the format: - * [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>, - * where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b - */ -static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec) +static const struct bpf_core_relo *find_relo_core(struct bpf_program *prog, int insn_idx) { - const struct btf_type *t; - const struct btf_enum *e; - const char *s; - __u32 type_id; + struct reloc_desc *relo; int i; - type_id = spec->root_type_id; - t = btf__type_by_id(spec->btf, type_id); - s = btf__name_by_offset(spec->btf, t->name_off); - - libbpf_print(level, "[%u] %s %s", type_id, btf_kind_str(t), str_is_empty(s) ? "<anon>" : s); - - if (core_relo_is_type_based(spec->relo_kind)) - return; - - if (core_relo_is_enumval_based(spec->relo_kind)) { - t = skip_mods_and_typedefs(spec->btf, type_id, NULL); - e = btf_enum(t) + spec->raw_spec[0]; - s = btf__name_by_offset(spec->btf, e->name_off); - - libbpf_print(level, "::%s = %u", s, e->val); - return; - } - - if (core_relo_is_field_based(spec->relo_kind)) { - for (i = 0; i < spec->len; i++) { - if (spec->spec[i].name) - libbpf_print(level, ".%s", spec->spec[i].name); - else if (i > 0 || spec->spec[i].idx > 0) - libbpf_print(level, "[%u]", spec->spec[i].idx); - } - - libbpf_print(level, " ("); - for (i = 0; i < spec->raw_len; i++) - libbpf_print(level, "%s%d", i == 0 ? "" : ":", spec->raw_spec[i]); + for (i = 0; i < prog->nr_reloc; i++) { + relo = &prog->reloc_desc[i]; + if (relo->type != RELO_CORE || relo->insn_idx != insn_idx) + continue; - if (spec->bit_offset % 8) - libbpf_print(level, " @ offset %u.%u)", - spec->bit_offset / 8, spec->bit_offset % 8); - else - libbpf_print(level, " @ offset %u)", spec->bit_offset / 8); - return; + return relo->core_relo; } -} - -static size_t bpf_core_hash_fn(const void *key, void *ctx) -{ - return (size_t)key; -} -static bool bpf_core_equal_fn(const void *k1, const void *k2, void *ctx) -{ - return k1 == k2; + return NULL; } -static void *u32_as_hash_key(__u32 x) +static int bpf_core_resolve_relo(struct bpf_program *prog, + const struct bpf_core_relo *relo, + int relo_idx, + const struct btf *local_btf, + struct hashmap *cand_cache, + struct bpf_core_relo_res *targ_res) { - return (void *)(uintptr_t)x; -} - -/* - * CO-RE relocate single instruction. - * - * The outline and important points of the algorithm: - * 1. For given local type, find corresponding candidate target types. - * Candidate type is a type with the same "essential" name, ignoring - * everything after last triple underscore (___). E.g., `sample`, - * `sample___flavor_one`, `sample___flavor_another_one`, are all candidates - * for each other. Names with triple underscore are referred to as - * "flavors" and are useful, among other things, to allow to - * specify/support incompatible variations of the same kernel struct, which - * might differ between different kernel versions and/or build - * configurations. - * - * N.B. Struct "flavors" could be generated by bpftool's BTF-to-C - * converter, when deduplicated BTF of a kernel still contains more than - * one different types with the same name. In that case, ___2, ___3, etc - * are appended starting from second name conflict. But start flavors are - * also useful to be defined "locally", in BPF program, to extract same - * data from incompatible changes between different kernel - * versions/configurations. For instance, to handle field renames between - * kernel versions, one can use two flavors of the struct name with the - * same common name and use conditional relocations to extract that field, - * depending on target kernel version. - * 2. For each candidate type, try to match local specification to this - * candidate target type. Matching involves finding corresponding - * high-level spec accessors, meaning that all named fields should match, - * as well as all array accesses should be within the actual bounds. Also, - * types should be compatible (see bpf_core_fields_are_compat for details). - * 3. It is supported and expected that there might be multiple flavors - * matching the spec. As long as all the specs resolve to the same set of - * offsets across all candidates, there is no error. If there is any - * ambiguity, CO-RE relocation will fail. This is necessary to accomodate - * imprefection of BTF deduplication, which can cause slight duplication of - * the same BTF type, if some directly or indirectly referenced (by - * pointer) type gets resolved to different actual types in different - * object files. If such situation occurs, deduplicated BTF will end up - * with two (or more) structurally identical types, which differ only in - * types they refer to through pointer. This should be OK in most cases and - * is not an error. - * 4. Candidate types search is performed by linearly scanning through all - * types in target BTF. It is anticipated that this is overall more - * efficient memory-wise and not significantly worse (if not better) - * CPU-wise compared to prebuilding a map from all local type names to - * a list of candidate type names. It's also sped up by caching resolved - * list of matching candidates per each local "root" type ID, that has at - * least one bpf_core_relo associated with it. This list is shared - * between multiple relocations for the same type ID and is updated as some - * of the candidates are pruned due to structural incompatibility. - */ -static int bpf_core_apply_relo(struct bpf_program *prog, - const struct bpf_core_relo *relo, - int relo_idx, - const struct btf *local_btf, - const struct btf *targ_btf, - struct hashmap *cand_cache) -{ - struct bpf_core_spec local_spec, cand_spec, targ_spec = {}; - const void *type_key = u32_as_hash_key(relo->type_id); - struct bpf_core_relo_res cand_res, targ_res; + struct bpf_core_spec specs_scratch[3] = {}; + struct bpf_core_cand_list *cands = NULL; + const char *prog_name = prog->name; const struct btf_type *local_type; const char *local_name; - struct ids_vec *cand_ids; - __u32 local_id, cand_id; - const char *spec_str; - int i, j, err; + __u32 local_id = relo->type_id; + int err; - local_id = relo->type_id; local_type = btf__type_by_id(local_btf, local_id); if (!local_type) return -EINVAL; @@ -5683,171 +5740,50 @@ static int bpf_core_apply_relo(struct bpf_program *prog, if (!local_name) return -EINVAL; - spec_str = btf__name_by_offset(local_btf, relo->access_str_off); - if (str_is_empty(spec_str)) - return -EINVAL; - - err = bpf_core_parse_spec(local_btf, local_id, spec_str, relo->kind, &local_spec); - if (err) { - pr_warn("prog '%s': relo #%d: parsing [%d] %s %s + %s failed: %d\n", - prog->name, relo_idx, local_id, btf_kind_str(local_type), - str_is_empty(local_name) ? "<anon>" : local_name, - spec_str, err); - return -EINVAL; - } - - pr_debug("prog '%s': relo #%d: kind <%s> (%d), spec is ", prog->name, - relo_idx, core_relo_kind_str(relo->kind), relo->kind); - bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec); - libbpf_print(LIBBPF_DEBUG, "\n"); - - /* TYPE_ID_LOCAL relo is special and doesn't need candidate search */ - if (relo->kind == BPF_TYPE_ID_LOCAL) { - targ_res.validate = true; - targ_res.poison = false; - targ_res.orig_val = local_spec.root_type_id; - targ_res.new_val = local_spec.root_type_id; - goto patch_insn; - } - - /* libbpf doesn't support candidate search for anonymous types */ - if (str_is_empty(spec_str)) { - pr_warn("prog '%s': relo #%d: <%s> (%d) relocation doesn't support anonymous types\n", - prog->name, relo_idx, core_relo_kind_str(relo->kind), relo->kind); - return -EOPNOTSUPP; - } - - if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) { - cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf); - if (IS_ERR(cand_ids)) { - pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld", - prog->name, relo_idx, local_id, btf_kind_str(local_type), - local_name, PTR_ERR(cand_ids)); - return PTR_ERR(cand_ids); + if (relo->kind != BPF_CORE_TYPE_ID_LOCAL && + !hashmap__find(cand_cache, local_id, &cands)) { + cands = bpf_core_find_cands(prog->obj, local_btf, local_id); + if (IS_ERR(cands)) { + pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n", + prog_name, relo_idx, local_id, btf_kind_str(local_type), + local_name, PTR_ERR(cands)); + return PTR_ERR(cands); } - err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL); + err = hashmap__set(cand_cache, local_id, cands, NULL, NULL); if (err) { - bpf_core_free_cands(cand_ids); - return err; - } - } - - for (i = 0, j = 0; i < cand_ids->len; i++) { - cand_id = cand_ids->data[i]; - err = bpf_core_spec_match(&local_spec, targ_btf, cand_id, &cand_spec); - if (err < 0) { - pr_warn("prog '%s': relo #%d: error matching candidate #%d ", - prog->name, relo_idx, i); - bpf_core_dump_spec(LIBBPF_WARN, &cand_spec); - libbpf_print(LIBBPF_WARN, ": %d\n", err); - return err; - } - - pr_debug("prog '%s': relo #%d: %s candidate #%d ", prog->name, - relo_idx, err == 0 ? "non-matching" : "matching", i); - bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec); - libbpf_print(LIBBPF_DEBUG, "\n"); - - if (err == 0) - continue; - - err = bpf_core_calc_relo(prog, relo, relo_idx, &local_spec, &cand_spec, &cand_res); - if (err) + bpf_core_free_cands(cands); return err; - - if (j == 0) { - targ_res = cand_res; - targ_spec = cand_spec; - } else if (cand_spec.bit_offset != targ_spec.bit_offset) { - /* if there are many field relo candidates, they - * should all resolve to the same bit offset - */ - pr_warn("prog '%s': relo #%d: field offset ambiguity: %u != %u\n", - prog->name, relo_idx, cand_spec.bit_offset, - targ_spec.bit_offset); - return -EINVAL; - } else if (cand_res.poison != targ_res.poison || cand_res.new_val != targ_res.new_val) { - /* all candidates should result in the same relocation - * decision and value, otherwise it's dangerous to - * proceed due to ambiguity - */ - pr_warn("prog '%s': relo #%d: relocation decision ambiguity: %s %u != %s %u\n", - prog->name, relo_idx, - cand_res.poison ? "failure" : "success", cand_res.new_val, - targ_res.poison ? "failure" : "success", targ_res.new_val); - return -EINVAL; } - - cand_ids->data[j++] = cand_spec.root_type_id; - } - - /* - * For BPF_FIELD_EXISTS relo or when used BPF program has field - * existence checks or kernel version/config checks, it's expected - * that we might not find any candidates. In this case, if field - * wasn't found in any candidate, the list of candidates shouldn't - * change at all, we'll just handle relocating appropriately, - * depending on relo's kind. - */ - if (j > 0) - cand_ids->len = j; - - /* - * If no candidates were found, it might be both a programmer error, - * as well as expected case, depending whether instruction w/ - * relocation is guarded in some way that makes it unreachable (dead - * code) if relocation can't be resolved. This is handled in - * bpf_core_patch_insn() uniformly by replacing that instruction with - * BPF helper call insn (using invalid helper ID). If that instruction - * is indeed unreachable, then it will be ignored and eliminated by - * verifier. If it was an error, then verifier will complain and point - * to a specific instruction number in its log. - */ - if (j == 0) { - pr_debug("prog '%s': relo #%d: no matching targets found\n", - prog->name, relo_idx); - - /* calculate single target relo result explicitly */ - err = bpf_core_calc_relo(prog, relo, relo_idx, &local_spec, NULL, &targ_res); - if (err) - return err; - } - -patch_insn: - /* bpf_core_patch_insn() should know how to handle missing targ_spec */ - err = bpf_core_patch_insn(prog, relo, relo_idx, &targ_res); - if (err) { - pr_warn("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n", - prog->name, relo_idx, relo->insn_off, err); - return -EINVAL; } - return 0; + return bpf_core_calc_relo_insn(prog_name, relo, relo_idx, local_btf, cands, specs_scratch, + targ_res); } static int bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) { const struct btf_ext_info_sec *sec; + struct bpf_core_relo_res targ_res; const struct bpf_core_relo *rec; const struct btf_ext_info *seg; struct hashmap_entry *entry; struct hashmap *cand_cache = NULL; struct bpf_program *prog; - struct btf *targ_btf; + struct bpf_insn *insn; const char *sec_name; - int i, err = 0, insn_idx, sec_idx; + int i, err = 0, insn_idx, sec_idx, sec_num; if (obj->btf_ext->core_relo_info.len == 0) return 0; - if (targ_btf_path) - targ_btf = btf__parse(targ_btf_path, NULL); - else - targ_btf = obj->btf_vmlinux; - if (IS_ERR_OR_NULL(targ_btf)) { - pr_warn("failed to get target BTF: %ld\n", PTR_ERR(targ_btf)); - return PTR_ERR(targ_btf); + if (targ_btf_path) { + obj->btf_vmlinux_override = btf__parse(targ_btf_path, NULL); + err = libbpf_get_error(obj->btf_vmlinux_override); + if (err) { + pr_warn("failed to parse target BTF: %d\n", err); + return err; + } } cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL); @@ -5857,71 +5793,146 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) } seg = &obj->btf_ext->core_relo_info; + sec_num = 0; for_each_btf_ext_sec(seg, sec) { + sec_idx = seg->sec_idxs[sec_num]; + sec_num++; + sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); if (str_is_empty(sec_name)) { err = -EINVAL; goto out; } - /* bpf_object's ELF is gone by now so it's not easy to find - * section index by section name, but we can find *any* - * bpf_program within desired section name and use it's - * prog->sec_idx to do a proper search by section index and - * instruction offset - */ - prog = NULL; - for (i = 0; i < obj->nr_programs; i++) { - prog = &obj->programs[i]; - if (strcmp(prog->sec_name, sec_name) == 0) - break; - } - if (!prog) { - pr_warn("sec '%s': failed to find a BPF program\n", sec_name); - return -ENOENT; - } - sec_idx = prog->sec_idx; - pr_debug("sec '%s': found %d CO-RE relocations\n", - sec_name, sec->num_info); + pr_debug("sec '%s': found %d CO-RE relocations\n", sec_name, sec->num_info); for_each_btf_ext_rec(seg, sec, i, rec) { + if (rec->insn_off % BPF_INSN_SZ) + return -EINVAL; insn_idx = rec->insn_off / BPF_INSN_SZ; prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx); if (!prog) { - pr_warn("sec '%s': failed to find program at insn #%d for CO-RE offset relocation #%d\n", - sec_name, insn_idx, i); - err = -EINVAL; - goto out; + /* When __weak subprog is "overridden" by another instance + * of the subprog from a different object file, linker still + * appends all the .BTF.ext info that used to belong to that + * eliminated subprogram. + * This is similar to what x86-64 linker does for relocations. + * So just ignore such relocations just like we ignore + * subprog instructions when discovering subprograms. + */ + pr_debug("sec '%s': skipping CO-RE relocation #%d for insn #%d belonging to eliminated weak subprogram\n", + sec_name, i, insn_idx); + continue; } /* no need to apply CO-RE relocation if the program is * not going to be loaded */ - if (!prog->load) + if (!prog->autoload) + continue; + + /* adjust insn_idx from section frame of reference to the local + * program's frame of reference; (sub-)program code is not yet + * relocated, so it's enough to just subtract in-section offset + */ + insn_idx = insn_idx - prog->sec_insn_off; + if (insn_idx >= prog->insns_cnt) + return -EINVAL; + insn = &prog->insns[insn_idx]; + + err = record_relo_core(prog, rec, insn_idx); + if (err) { + pr_warn("prog '%s': relo #%d: failed to record relocation: %d\n", + prog->name, i, err); + goto out; + } + + if (prog->obj->gen_loader) continue; - err = bpf_core_apply_relo(prog, rec, i, obj->btf, - targ_btf, cand_cache); + err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res); if (err) { pr_warn("prog '%s': relo #%d: failed to relocate: %d\n", prog->name, i, err); goto out; } + + err = bpf_core_patch_insn(prog->name, insn, insn_idx, rec, i, &targ_res); + if (err) { + pr_warn("prog '%s': relo #%d: failed to patch insn #%u: %d\n", + prog->name, i, insn_idx, err); + goto out; + } } } out: - /* obj->btf_vmlinux is freed at the end of object load phase */ - if (targ_btf != obj->btf_vmlinux) - btf__free(targ_btf); + /* obj->btf_vmlinux and module BTFs are freed after object load */ + btf__free(obj->btf_vmlinux_override); + obj->btf_vmlinux_override = NULL; + if (!IS_ERR_OR_NULL(cand_cache)) { hashmap__for_each_entry(cand_cache, entry, i) { - bpf_core_free_cands(entry->value); + bpf_core_free_cands(entry->pvalue); } hashmap__free(cand_cache); } return err; } +/* base map load ldimm64 special constant, used also for log fixup logic */ +#define POISON_LDIMM64_MAP_BASE 2001000000 +#define POISON_LDIMM64_MAP_PFX "200100" + +static void poison_map_ldimm64(struct bpf_program *prog, int relo_idx, + int insn_idx, struct bpf_insn *insn, + int map_idx, const struct bpf_map *map) +{ + int i; + + pr_debug("prog '%s': relo #%d: poisoning insn #%d that loads map #%d '%s'\n", + prog->name, relo_idx, insn_idx, map_idx, map->name); + + /* we turn single ldimm64 into two identical invalid calls */ + for (i = 0; i < 2; i++) { + insn->code = BPF_JMP | BPF_CALL; + insn->dst_reg = 0; + insn->src_reg = 0; + insn->off = 0; + /* if this instruction is reachable (not a dead code), + * verifier will complain with something like: + * invalid func unknown#2001000123 + * where lower 123 is map index into obj->maps[] array + */ + insn->imm = POISON_LDIMM64_MAP_BASE + map_idx; + + insn++; + } +} + +/* unresolved kfunc call special constant, used also for log fixup logic */ +#define POISON_CALL_KFUNC_BASE 2002000000 +#define POISON_CALL_KFUNC_PFX "2002" + +static void poison_kfunc_call(struct bpf_program *prog, int relo_idx, + int insn_idx, struct bpf_insn *insn, + int ext_idx, const struct extern_desc *ext) +{ + pr_debug("prog '%s': relo #%d: poisoning insn #%d that calls kfunc '%s'\n", + prog->name, relo_idx, insn_idx, ext->name); + + /* we turn kfunc call into invalid helper call with identifiable constant */ + insn->code = BPF_JMP | BPF_CALL; + insn->dst_reg = 0; + insn->src_reg = 0; + insn->off = 0; + /* if this instruction is reachable (not a dead code), + * verifier will complain with something like: + * invalid func unknown#2001000123 + * where lower 123 is extern index into obj->externs[] array + */ + insn->imm = POISON_CALL_KFUNC_BASE + ext_idx; +} + /* Relocate data references within program code: * - map references; * - global variable references; @@ -5935,39 +5946,83 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) for (i = 0; i < prog->nr_reloc; i++) { struct reloc_desc *relo = &prog->reloc_desc[i]; struct bpf_insn *insn = &prog->insns[relo->insn_idx]; + const struct bpf_map *map; struct extern_desc *ext; switch (relo->type) { case RELO_LD64: - insn[0].src_reg = BPF_PSEUDO_MAP_FD; - insn[0].imm = obj->maps[relo->map_idx].fd; - relo->processed = true; + map = &obj->maps[relo->map_idx]; + if (obj->gen_loader) { + insn[0].src_reg = BPF_PSEUDO_MAP_IDX; + insn[0].imm = relo->map_idx; + } else if (map->autocreate) { + insn[0].src_reg = BPF_PSEUDO_MAP_FD; + insn[0].imm = map->fd; + } else { + poison_map_ldimm64(prog, i, relo->insn_idx, insn, + relo->map_idx, map); + } break; case RELO_DATA: - insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; + map = &obj->maps[relo->map_idx]; insn[1].imm = insn[0].imm + relo->sym_off; - insn[0].imm = obj->maps[relo->map_idx].fd; - relo->processed = true; + if (obj->gen_loader) { + insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE; + insn[0].imm = relo->map_idx; + } else if (map->autocreate) { + insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; + insn[0].imm = map->fd; + } else { + poison_map_ldimm64(prog, i, relo->insn_idx, insn, + relo->map_idx, map); + } break; - case RELO_EXTERN: - ext = &obj->externs[relo->sym_off]; + case RELO_EXTERN_LD64: + ext = &obj->externs[relo->ext_idx]; if (ext->type == EXT_KCFG) { - insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; - insn[0].imm = obj->maps[obj->kconfig_map_idx].fd; + if (obj->gen_loader) { + insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE; + insn[0].imm = obj->kconfig_map_idx; + } else { + insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; + insn[0].imm = obj->maps[obj->kconfig_map_idx].fd; + } insn[1].imm = ext->kcfg.data_off; } else /* EXT_KSYM */ { - if (ext->ksym.type_id) { /* typed ksyms */ + if (ext->ksym.type_id && ext->is_set) { /* typed ksyms */ insn[0].src_reg = BPF_PSEUDO_BTF_ID; - insn[0].imm = ext->ksym.vmlinux_btf_id; - } else { /* typeless ksyms */ + insn[0].imm = ext->ksym.kernel_btf_id; + insn[1].imm = ext->ksym.kernel_btf_obj_fd; + } else { /* typeless ksyms or unresolved typed ksyms */ insn[0].imm = (__u32)ext->ksym.addr; insn[1].imm = ext->ksym.addr >> 32; } } - relo->processed = true; + break; + case RELO_EXTERN_CALL: + ext = &obj->externs[relo->ext_idx]; + insn[0].src_reg = BPF_PSEUDO_KFUNC_CALL; + if (ext->is_set) { + insn[0].imm = ext->ksym.kernel_btf_id; + insn[0].off = ext->ksym.btf_fd_idx; + } else { /* unresolved weak kfunc call */ + poison_kfunc_call(prog, i, relo->insn_idx, insn, + relo->ext_idx, ext); + } + break; + case RELO_SUBPROG_ADDR: + if (insn[0].src_reg != BPF_PSEUDO_FUNC) { + pr_warn("prog '%s': relo #%d: bad insn\n", + prog->name, i); + return -EINVAL; + } + /* handled already */ break; case RELO_CALL: - /* will be handled as a follow up pass */ + /* handled already */ + break; + case RELO_CORE: + /* will be handled by bpf_program_record_relos() */ break; default: pr_warn("prog '%s': relo #%d: bad relo type %d\n", @@ -5989,14 +6044,13 @@ static int adjust_prog_btf_ext_info(const struct bpf_object *obj, void *rec, *rec_end, *new_prog_info; const struct btf_ext_info_sec *sec; size_t old_sz, new_sz; - const char *sec_name; - int i, off_adj; + int i, sec_num, sec_idx, off_adj; + sec_num = 0; for_each_btf_ext_sec(ext_info, sec) { - sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); - if (!sec_name) - return -EINVAL; - if (strcmp(sec_name, prog->sec_name) != 0) + sec_idx = ext_info->sec_idxs[sec_num]; + sec_num++; + if (prog->sec_idx != sec_idx) continue; for_each_btf_ext_rec(ext_info, sec, i, rec) { @@ -6056,9 +6110,9 @@ reloc_prog_func_and_line_info(const struct bpf_object *obj, int err; /* no .BTF.ext relocation if .BTF.ext is missing or kernel doesn't - * supprot func/line info + * support func/line info */ - if (!obj->btf_ext || !kernel_supports(FEAT_BTF_FUNC)) + if (!obj->btf_ext || !kernel_supports(obj, FEAT_BTF_FUNC)) return 0; /* only attempt func info relocation if main program's func_info @@ -6132,18 +6186,81 @@ static int cmp_relo_by_insn_idx(const void *key, const void *elem) static struct reloc_desc *find_prog_insn_relo(const struct bpf_program *prog, size_t insn_idx) { + if (!prog->nr_reloc) + return NULL; return bsearch(&insn_idx, prog->reloc_desc, prog->nr_reloc, sizeof(*prog->reloc_desc), cmp_relo_by_insn_idx); } +static int append_subprog_relos(struct bpf_program *main_prog, struct bpf_program *subprog) +{ + int new_cnt = main_prog->nr_reloc + subprog->nr_reloc; + struct reloc_desc *relos; + int i; + + if (main_prog == subprog) + return 0; + relos = libbpf_reallocarray(main_prog->reloc_desc, new_cnt, sizeof(*relos)); + /* if new count is zero, reallocarray can return a valid NULL result; + * in this case the previous pointer will be freed, so we *have to* + * reassign old pointer to the new value (even if it's NULL) + */ + if (!relos && new_cnt) + return -ENOMEM; + if (subprog->nr_reloc) + memcpy(relos + main_prog->nr_reloc, subprog->reloc_desc, + sizeof(*relos) * subprog->nr_reloc); + + for (i = main_prog->nr_reloc; i < new_cnt; i++) + relos[i].insn_idx += subprog->sub_insn_off; + /* After insn_idx adjustment the 'relos' array is still sorted + * by insn_idx and doesn't break bsearch. + */ + main_prog->reloc_desc = relos; + main_prog->nr_reloc = new_cnt; + return 0; +} + +static int +bpf_object__append_subprog_code(struct bpf_object *obj, struct bpf_program *main_prog, + struct bpf_program *subprog) +{ + struct bpf_insn *insns; + size_t new_cnt; + int err; + + subprog->sub_insn_off = main_prog->insns_cnt; + + new_cnt = main_prog->insns_cnt + subprog->insns_cnt; + insns = libbpf_reallocarray(main_prog->insns, new_cnt, sizeof(*insns)); + if (!insns) { + pr_warn("prog '%s': failed to realloc prog code\n", main_prog->name); + return -ENOMEM; + } + main_prog->insns = insns; + main_prog->insns_cnt = new_cnt; + + memcpy(main_prog->insns + subprog->sub_insn_off, subprog->insns, + subprog->insns_cnt * sizeof(*insns)); + + pr_debug("prog '%s': added %zu insns from sub-prog '%s'\n", + main_prog->name, subprog->insns_cnt, subprog->name); + + /* The subprog insns are now appended. Append its relos too. */ + err = append_subprog_relos(main_prog, subprog); + if (err) + return err; + return 0; +} + static int bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, struct bpf_program *prog) { - size_t sub_insn_idx, insn_idx, new_cnt; + size_t sub_insn_idx, insn_idx; struct bpf_program *subprog; - struct bpf_insn *insns, *insn; struct reloc_desc *relo; + struct bpf_insn *insn; int err; err = reloc_prog_func_and_line_info(obj, main_prog, prog); @@ -6152,11 +6269,16 @@ bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, for (insn_idx = 0; insn_idx < prog->sec_insn_cnt; insn_idx++) { insn = &main_prog->insns[prog->sub_insn_off + insn_idx]; - if (!insn_is_subprog_call(insn)) + if (!insn_is_subprog_call(insn) && !insn_is_pseudo_func(insn)) continue; relo = find_prog_insn_relo(prog, insn_idx); - if (relo && relo->type != RELO_CALL) { + if (relo && relo->type == RELO_EXTERN_CALL) + /* kfunc relocations will be handled later + * in bpf_object__relocate_data() + */ + continue; + if (relo && relo->type != RELO_CALL && relo->type != RELO_SUBPROG_ADDR) { pr_warn("prog '%s': unexpected relo for insn #%zu, type %d\n", prog->name, insn_idx, relo->type); return -LIBBPF_ERRNO__RELOC; @@ -6168,8 +6290,22 @@ bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, * call always has imm = -1, but for static functions * relocation is against STT_SECTION and insn->imm * points to a start of a static function + * + * for subprog addr relocation, the relo->sym_off + insn->imm is + * the byte offset in the corresponding section. + */ + if (relo->type == RELO_CALL) + sub_insn_idx = relo->sym_off / BPF_INSN_SZ + insn->imm + 1; + else + sub_insn_idx = (relo->sym_off + insn->imm) / BPF_INSN_SZ; + } else if (insn_is_pseudo_func(insn)) { + /* + * RELO_SUBPROG_ADDR relo is always emitted even if both + * functions are in the same section, so it shouldn't reach here. */ - sub_insn_idx = relo->sym_off / BPF_INSN_SZ + insn->imm + 1; + pr_warn("prog '%s': missing subprog addr relo for insn #%zu\n", + prog->name, insn_idx); + return -LIBBPF_ERRNO__RELOC; } else { /* if subprogram call is to a static function within * the same ELF section, there won't be any relocation @@ -6199,23 +6335,9 @@ bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, * and relocate. */ if (subprog->sub_insn_off == 0) { - subprog->sub_insn_off = main_prog->insns_cnt; - - new_cnt = main_prog->insns_cnt + subprog->insns_cnt; - insns = libbpf_reallocarray(main_prog->insns, new_cnt, sizeof(*insns)); - if (!insns) { - pr_warn("prog '%s': failed to realloc prog code\n", main_prog->name); - return -ENOMEM; - } - main_prog->insns = insns; - main_prog->insns_cnt = new_cnt; - - memcpy(main_prog->insns + subprog->sub_insn_off, subprog->insns, - subprog->insns_cnt * sizeof(*insns)); - - pr_debug("prog '%s': added %zu insns from sub-prog '%s'\n", - main_prog->name, subprog->insns_cnt, subprog->name); - + err = bpf_object__append_subprog_code(obj, main_prog, subprog); + if (err) + return err; err = bpf_object__reloc_code(obj, main_prog, subprog); if (err) return err; @@ -6229,12 +6351,10 @@ bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, * prog; each main prog can have a different set of * subprograms appended (potentially in different order as * well), so position of any subprog can be different for - * different main programs */ + * different main programs + */ insn->imm = subprog->sub_insn_off - (prog->sub_insn_off + insn_idx) - 1; - if (relo) - relo->processed = true; - pr_debug("prog '%s': insn #%zu relocated, imm %d points to subprog '%s' (now at %zu offset)\n", prog->name, insn_idx, insn->imm, subprog->name, subprog->sub_insn_off); } @@ -6327,7 +6447,7 @@ static int bpf_object__relocate_calls(struct bpf_object *obj, struct bpf_program *prog) { struct bpf_program *subprog; - int i, j, err; + int i, err; /* mark all subprogs as not relocated (yet) within the context of * current main program @@ -6338,24 +6458,463 @@ bpf_object__relocate_calls(struct bpf_object *obj, struct bpf_program *prog) continue; subprog->sub_insn_off = 0; - for (j = 0; j < subprog->nr_reloc; j++) - if (subprog->reloc_desc[j].type == RELO_CALL) - subprog->reloc_desc[j].processed = false; } err = bpf_object__reloc_code(obj, prog, prog); if (err) return err; + return 0; +} + +static void +bpf_object__free_relocs(struct bpf_object *obj) +{ + struct bpf_program *prog; + int i; + + /* free up relocation descriptors */ + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + zfree(&prog->reloc_desc); + prog->nr_reloc = 0; + } +} + +static int cmp_relocs(const void *_a, const void *_b) +{ + const struct reloc_desc *a = _a; + const struct reloc_desc *b = _b; + + if (a->insn_idx != b->insn_idx) + return a->insn_idx < b->insn_idx ? -1 : 1; + + /* no two relocations should have the same insn_idx, but ... */ + if (a->type != b->type) + return a->type < b->type ? -1 : 1; return 0; } -static int -bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) +static void bpf_object__sort_relos(struct bpf_object *obj) +{ + int i; + + for (i = 0; i < obj->nr_programs; i++) { + struct bpf_program *p = &obj->programs[i]; + + if (!p->nr_reloc) + continue; + + qsort(p->reloc_desc, p->nr_reloc, sizeof(*p->reloc_desc), cmp_relocs); + } +} + +static int bpf_prog_assign_exc_cb(struct bpf_object *obj, struct bpf_program *prog) +{ + const char *str = "exception_callback:"; + size_t pfx_len = strlen(str); + int i, j, n; + + if (!obj->btf || !kernel_supports(obj, FEAT_BTF_DECL_TAG)) + return 0; + + n = btf__type_cnt(obj->btf); + for (i = 1; i < n; i++) { + const char *name; + struct btf_type *t; + + t = btf_type_by_id(obj->btf, i); + if (!btf_is_decl_tag(t) || btf_decl_tag(t)->component_idx != -1) + continue; + + name = btf__str_by_offset(obj->btf, t->name_off); + if (strncmp(name, str, pfx_len) != 0) + continue; + + t = btf_type_by_id(obj->btf, t->type); + if (!btf_is_func(t) || btf_func_linkage(t) != BTF_FUNC_GLOBAL) { + pr_warn("prog '%s': exception_callback:<value> decl tag not applied to the main program\n", + prog->name); + return -EINVAL; + } + if (strcmp(prog->name, btf__str_by_offset(obj->btf, t->name_off)) != 0) + continue; + /* Multiple callbacks are specified for the same prog, + * the verifier will eventually return an error for this + * case, hence simply skip appending a subprog. + */ + if (prog->exception_cb_idx >= 0) { + prog->exception_cb_idx = -1; + break; + } + + name += pfx_len; + if (str_is_empty(name)) { + pr_warn("prog '%s': exception_callback:<value> decl tag contains empty value\n", + prog->name); + return -EINVAL; + } + + for (j = 0; j < obj->nr_programs; j++) { + struct bpf_program *subprog = &obj->programs[j]; + + if (!prog_is_subprog(obj, subprog)) + continue; + if (strcmp(name, subprog->name) != 0) + continue; + /* Enforce non-hidden, as from verifier point of + * view it expects global functions, whereas the + * mark_btf_static fixes up linkage as static. + */ + if (!subprog->sym_global || subprog->mark_btf_static) { + pr_warn("prog '%s': exception callback %s must be a global non-hidden function\n", + prog->name, subprog->name); + return -EINVAL; + } + /* Let's see if we already saw a static exception callback with the same name */ + if (prog->exception_cb_idx >= 0) { + pr_warn("prog '%s': multiple subprogs with same name as exception callback '%s'\n", + prog->name, subprog->name); + return -EINVAL; + } + prog->exception_cb_idx = j; + break; + } + + if (prog->exception_cb_idx >= 0) + continue; + + pr_warn("prog '%s': cannot find exception callback '%s'\n", prog->name, name); + return -ENOENT; + } + + return 0; +} + +static struct { + enum bpf_prog_type prog_type; + const char *ctx_name; +} global_ctx_map[] = { + { BPF_PROG_TYPE_CGROUP_DEVICE, "bpf_cgroup_dev_ctx" }, + { BPF_PROG_TYPE_CGROUP_SKB, "__sk_buff" }, + { BPF_PROG_TYPE_CGROUP_SOCK, "bpf_sock" }, + { BPF_PROG_TYPE_CGROUP_SOCK_ADDR, "bpf_sock_addr" }, + { BPF_PROG_TYPE_CGROUP_SOCKOPT, "bpf_sockopt" }, + { BPF_PROG_TYPE_CGROUP_SYSCTL, "bpf_sysctl" }, + { BPF_PROG_TYPE_FLOW_DISSECTOR, "__sk_buff" }, + { BPF_PROG_TYPE_KPROBE, "bpf_user_pt_regs_t" }, + { BPF_PROG_TYPE_LWT_IN, "__sk_buff" }, + { BPF_PROG_TYPE_LWT_OUT, "__sk_buff" }, + { BPF_PROG_TYPE_LWT_SEG6LOCAL, "__sk_buff" }, + { BPF_PROG_TYPE_LWT_XMIT, "__sk_buff" }, + { BPF_PROG_TYPE_NETFILTER, "bpf_nf_ctx" }, + { BPF_PROG_TYPE_PERF_EVENT, "bpf_perf_event_data" }, + { BPF_PROG_TYPE_RAW_TRACEPOINT, "bpf_raw_tracepoint_args" }, + { BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, "bpf_raw_tracepoint_args" }, + { BPF_PROG_TYPE_SCHED_ACT, "__sk_buff" }, + { BPF_PROG_TYPE_SCHED_CLS, "__sk_buff" }, + { BPF_PROG_TYPE_SK_LOOKUP, "bpf_sk_lookup" }, + { BPF_PROG_TYPE_SK_MSG, "sk_msg_md" }, + { BPF_PROG_TYPE_SK_REUSEPORT, "sk_reuseport_md" }, + { BPF_PROG_TYPE_SK_SKB, "__sk_buff" }, + { BPF_PROG_TYPE_SOCK_OPS, "bpf_sock_ops" }, + { BPF_PROG_TYPE_SOCKET_FILTER, "__sk_buff" }, + { BPF_PROG_TYPE_XDP, "xdp_md" }, + /* all other program types don't have "named" context structs */ +}; + +/* forward declarations for arch-specific underlying types of bpf_user_pt_regs_t typedef, + * for below __builtin_types_compatible_p() checks; + * with this approach we don't need any extra arch-specific #ifdef guards + */ +struct pt_regs; +struct user_pt_regs; +struct user_regs_struct; + +static bool need_func_arg_type_fixup(const struct btf *btf, const struct bpf_program *prog, + const char *subprog_name, int arg_idx, + int arg_type_id, const char *ctx_name) +{ + const struct btf_type *t; + const char *tname; + + /* check if existing parameter already matches verifier expectations */ + t = skip_mods_and_typedefs(btf, arg_type_id, NULL); + if (!btf_is_ptr(t)) + goto out_warn; + + /* typedef bpf_user_pt_regs_t is a special PITA case, valid for kprobe + * and perf_event programs, so check this case early on and forget + * about it for subsequent checks + */ + while (btf_is_mod(t)) + t = btf__type_by_id(btf, t->type); + if (btf_is_typedef(t) && + (prog->type == BPF_PROG_TYPE_KPROBE || prog->type == BPF_PROG_TYPE_PERF_EVENT)) { + tname = btf__str_by_offset(btf, t->name_off) ?: "<anon>"; + if (strcmp(tname, "bpf_user_pt_regs_t") == 0) + return false; /* canonical type for kprobe/perf_event */ + } + + /* now we can ignore typedefs moving forward */ + t = skip_mods_and_typedefs(btf, t->type, NULL); + + /* if it's `void *`, definitely fix up BTF info */ + if (btf_is_void(t)) + return true; + + /* if it's already proper canonical type, no need to fix up */ + tname = btf__str_by_offset(btf, t->name_off) ?: "<anon>"; + if (btf_is_struct(t) && strcmp(tname, ctx_name) == 0) + return false; + + /* special cases */ + switch (prog->type) { + case BPF_PROG_TYPE_KPROBE: + /* `struct pt_regs *` is expected, but we need to fix up */ + if (btf_is_struct(t) && strcmp(tname, "pt_regs") == 0) + return true; + break; + case BPF_PROG_TYPE_PERF_EVENT: + if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct pt_regs) && + btf_is_struct(t) && strcmp(tname, "pt_regs") == 0) + return true; + if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_pt_regs) && + btf_is_struct(t) && strcmp(tname, "user_pt_regs") == 0) + return true; + if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_regs_struct) && + btf_is_struct(t) && strcmp(tname, "user_regs_struct") == 0) + return true; + break; + case BPF_PROG_TYPE_RAW_TRACEPOINT: + case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE: + /* allow u64* as ctx */ + if (btf_is_int(t) && t->size == 8) + return true; + break; + default: + break; + } + +out_warn: + pr_warn("prog '%s': subprog '%s' arg#%d is expected to be of `struct %s *` type\n", + prog->name, subprog_name, arg_idx, ctx_name); + return false; +} + +static int clone_func_btf_info(struct btf *btf, int orig_fn_id, struct bpf_program *prog) +{ + int fn_id, fn_proto_id, ret_type_id, orig_proto_id; + int i, err, arg_cnt, fn_name_off, linkage; + struct btf_type *fn_t, *fn_proto_t, *t; + struct btf_param *p; + + /* caller already validated FUNC -> FUNC_PROTO validity */ + fn_t = btf_type_by_id(btf, orig_fn_id); + fn_proto_t = btf_type_by_id(btf, fn_t->type); + + /* Note that each btf__add_xxx() operation invalidates + * all btf_type and string pointers, so we need to be + * very careful when cloning BTF types. BTF type + * pointers have to be always refetched. And to avoid + * problems with invalidated string pointers, we + * add empty strings initially, then just fix up + * name_off offsets in place. Offsets are stable for + * existing strings, so that works out. + */ + fn_name_off = fn_t->name_off; /* we are about to invalidate fn_t */ + linkage = btf_func_linkage(fn_t); + orig_proto_id = fn_t->type; /* original FUNC_PROTO ID */ + ret_type_id = fn_proto_t->type; /* fn_proto_t will be invalidated */ + arg_cnt = btf_vlen(fn_proto_t); + + /* clone FUNC_PROTO and its params */ + fn_proto_id = btf__add_func_proto(btf, ret_type_id); + if (fn_proto_id < 0) + return -EINVAL; + + for (i = 0; i < arg_cnt; i++) { + int name_off; + + /* copy original parameter data */ + t = btf_type_by_id(btf, orig_proto_id); + p = &btf_params(t)[i]; + name_off = p->name_off; + + err = btf__add_func_param(btf, "", p->type); + if (err) + return err; + + fn_proto_t = btf_type_by_id(btf, fn_proto_id); + p = &btf_params(fn_proto_t)[i]; + p->name_off = name_off; /* use remembered str offset */ + } + + /* clone FUNC now, btf__add_func() enforces non-empty name, so use + * entry program's name as a placeholder, which we replace immediately + * with original name_off + */ + fn_id = btf__add_func(btf, prog->name, linkage, fn_proto_id); + if (fn_id < 0) + return -EINVAL; + + fn_t = btf_type_by_id(btf, fn_id); + fn_t->name_off = fn_name_off; /* reuse original string */ + + return fn_id; +} + +/* Check if main program or global subprog's function prototype has `arg:ctx` + * argument tags, and, if necessary, substitute correct type to match what BPF + * verifier would expect, taking into account specific program type. This + * allows to support __arg_ctx tag transparently on old kernels that don't yet + * have a native support for it in the verifier, making user's life much + * easier. + */ +static int bpf_program_fixup_func_info(struct bpf_object *obj, struct bpf_program *prog) +{ + const char *ctx_name = NULL, *ctx_tag = "arg:ctx", *fn_name; + struct bpf_func_info_min *func_rec; + struct btf_type *fn_t, *fn_proto_t; + struct btf *btf = obj->btf; + const struct btf_type *t; + struct btf_param *p; + int ptr_id = 0, struct_id, tag_id, orig_fn_id; + int i, n, arg_idx, arg_cnt, err, rec_idx; + int *orig_ids; + + /* no .BTF.ext, no problem */ + if (!obj->btf_ext || !prog->func_info) + return 0; + + /* don't do any fix ups if kernel natively supports __arg_ctx */ + if (kernel_supports(obj, FEAT_ARG_CTX_TAG)) + return 0; + + /* some BPF program types just don't have named context structs, so + * this fallback mechanism doesn't work for them + */ + for (i = 0; i < ARRAY_SIZE(global_ctx_map); i++) { + if (global_ctx_map[i].prog_type != prog->type) + continue; + ctx_name = global_ctx_map[i].ctx_name; + break; + } + if (!ctx_name) + return 0; + + /* remember original func BTF IDs to detect if we already cloned them */ + orig_ids = calloc(prog->func_info_cnt, sizeof(*orig_ids)); + if (!orig_ids) + return -ENOMEM; + for (i = 0; i < prog->func_info_cnt; i++) { + func_rec = prog->func_info + prog->func_info_rec_size * i; + orig_ids[i] = func_rec->type_id; + } + + /* go through each DECL_TAG with "arg:ctx" and see if it points to one + * of our subprogs; if yes and subprog is global and needs adjustment, + * clone and adjust FUNC -> FUNC_PROTO combo + */ + for (i = 1, n = btf__type_cnt(btf); i < n; i++) { + /* only DECL_TAG with "arg:ctx" value are interesting */ + t = btf__type_by_id(btf, i); + if (!btf_is_decl_tag(t)) + continue; + if (strcmp(btf__str_by_offset(btf, t->name_off), ctx_tag) != 0) + continue; + + /* only global funcs need adjustment, if at all */ + orig_fn_id = t->type; + fn_t = btf_type_by_id(btf, orig_fn_id); + if (!btf_is_func(fn_t) || btf_func_linkage(fn_t) != BTF_FUNC_GLOBAL) + continue; + + /* sanity check FUNC -> FUNC_PROTO chain, just in case */ + fn_proto_t = btf_type_by_id(btf, fn_t->type); + if (!fn_proto_t || !btf_is_func_proto(fn_proto_t)) + continue; + + /* find corresponding func_info record */ + func_rec = NULL; + for (rec_idx = 0; rec_idx < prog->func_info_cnt; rec_idx++) { + if (orig_ids[rec_idx] == t->type) { + func_rec = prog->func_info + prog->func_info_rec_size * rec_idx; + break; + } + } + /* current main program doesn't call into this subprog */ + if (!func_rec) + continue; + + /* some more sanity checking of DECL_TAG */ + arg_cnt = btf_vlen(fn_proto_t); + arg_idx = btf_decl_tag(t)->component_idx; + if (arg_idx < 0 || arg_idx >= arg_cnt) + continue; + + /* check if we should fix up argument type */ + p = &btf_params(fn_proto_t)[arg_idx]; + fn_name = btf__str_by_offset(btf, fn_t->name_off) ?: "<anon>"; + if (!need_func_arg_type_fixup(btf, prog, fn_name, arg_idx, p->type, ctx_name)) + continue; + + /* clone fn/fn_proto, unless we already did it for another arg */ + if (func_rec->type_id == orig_fn_id) { + int fn_id; + + fn_id = clone_func_btf_info(btf, orig_fn_id, prog); + if (fn_id < 0) { + err = fn_id; + goto err_out; + } + + /* point func_info record to a cloned FUNC type */ + func_rec->type_id = fn_id; + } + + /* create PTR -> STRUCT type chain to mark PTR_TO_CTX argument; + * we do it just once per main BPF program, as all global + * funcs share the same program type, so need only PTR -> + * STRUCT type chain + */ + if (ptr_id == 0) { + struct_id = btf__add_struct(btf, ctx_name, 0); + ptr_id = btf__add_ptr(btf, struct_id); + if (ptr_id < 0 || struct_id < 0) { + err = -EINVAL; + goto err_out; + } + } + + /* for completeness, clone DECL_TAG and point it to cloned param */ + tag_id = btf__add_decl_tag(btf, ctx_tag, func_rec->type_id, arg_idx); + if (tag_id < 0) { + err = -EINVAL; + goto err_out; + } + + /* all the BTF manipulations invalidated pointers, refetch them */ + fn_t = btf_type_by_id(btf, func_rec->type_id); + fn_proto_t = btf_type_by_id(btf, fn_t->type); + + /* fix up type ID pointed to by param */ + p = &btf_params(fn_proto_t)[arg_idx]; + p->type = ptr_id; + } + + free(orig_ids); + return 0; +err_out: + free(orig_ids); + return err; +} + +static int bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) { struct bpf_program *prog; - size_t i; + size_t i, j; int err; if (obj->btf_ext) { @@ -6365,24 +6924,34 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) err); return err; } + bpf_object__sort_relos(obj); } - /* relocate data references first for all programs and sub-programs, - * as they don't change relative to code locations, so subsequent - * subprogram processing won't need to re-calculate any of them + + /* Before relocating calls pre-process relocations and mark + * few ld_imm64 instructions that points to subprogs. + * Otherwise bpf_object__reloc_code() later would have to consider + * all ld_imm64 insns as relocation candidates. That would + * reduce relocation speed, since amount of find_prog_insn_relo() + * would increase and most of them will fail to find a relo. */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; - err = bpf_object__relocate_data(obj, prog); - if (err) { - pr_warn("prog '%s': failed to relocate data references: %d\n", - prog->name, err); - return err; + for (j = 0; j < prog->nr_reloc; j++) { + struct reloc_desc *relo = &prog->reloc_desc[j]; + struct bpf_insn *insn = &prog->insns[relo->insn_idx]; + + /* mark the insn, so it's recognized by insn_is_pseudo_func() */ + if (relo->type == RELO_SUBPROG_ADDR) + insn[0].src_reg = BPF_PSEUDO_FUNC; } } - /* now relocate subprogram calls and append used subprograms to main + + /* relocate subprogram calls and append used subprograms to main * programs; each copy of subprogram code needs to be relocated * differently for each main program, because its code location might - * have changed + * have changed. + * Append subprog relos to main programs to allow data relos to be + * processed after text is completely relocated. */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; @@ -6391,6 +6960,8 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) */ if (prog_is_subprog(obj, prog)) continue; + if (!prog->autoload) + continue; err = bpf_object__relocate_calls(obj, prog); if (err) { @@ -6398,33 +6969,74 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) prog->name, err); return err; } + + err = bpf_prog_assign_exc_cb(obj, prog); + if (err) + return err; + /* Now, also append exception callback if it has not been done already. */ + if (prog->exception_cb_idx >= 0) { + struct bpf_program *subprog = &obj->programs[prog->exception_cb_idx]; + + /* Calling exception callback directly is disallowed, which the + * verifier will reject later. In case it was processed already, + * we can skip this step, otherwise for all other valid cases we + * have to append exception callback now. + */ + if (subprog->sub_insn_off == 0) { + err = bpf_object__append_subprog_code(obj, prog, subprog); + if (err) + return err; + err = bpf_object__reloc_code(obj, prog, subprog); + if (err) + return err; + } + } } - /* free up relocation descriptors */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; - zfree(&prog->reloc_desc); - prog->nr_reloc = 0; + if (prog_is_subprog(obj, prog)) + continue; + if (!prog->autoload) + continue; + + /* Process data relos for main programs */ + err = bpf_object__relocate_data(obj, prog); + if (err) { + pr_warn("prog '%s': failed to relocate data references: %d\n", + prog->name, err); + return err; + } + + /* Fix up .BTF.ext information, if necessary */ + err = bpf_program_fixup_func_info(obj, prog); + if (err) { + pr_warn("prog '%s': failed to perform .BTF.ext fix ups: %d\n", + prog->name, err); + return err; + } } + return 0; } static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, - GElf_Shdr *shdr, Elf_Data *data); + Elf64_Shdr *shdr, Elf_Data *data); static int bpf_object__collect_map_relos(struct bpf_object *obj, - GElf_Shdr *shdr, Elf_Data *data) + Elf64_Shdr *shdr, Elf_Data *data) { const int bpf_ptr_sz = 8, host_ptr_sz = sizeof(void *); int i, j, nrels, new_sz; const struct btf_var_secinfo *vi = NULL; const struct btf_type *sec, *var, *def; - struct bpf_map *map = NULL, *targ_map; + struct bpf_map *map = NULL, *targ_map = NULL; + struct bpf_program *targ_prog = NULL; + bool is_prog_array, is_map_in_map; const struct btf_member *member; - const char *name, *mname; - Elf_Data *symbols; + const char *name, *mname, *type; unsigned int moff; - GElf_Sym sym; - GElf_Rel rel; + Elf64_Sym *sym; + Elf64_Rel *rel; void *tmp; if (!obj->efile.btf_maps_sec_btf_id || !obj->btf) @@ -6433,28 +7045,25 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj, if (!sec) return -EINVAL; - symbols = obj->efile.symbols; nrels = shdr->sh_size / shdr->sh_entsize; for (i = 0; i < nrels; i++) { - if (!gelf_getrel(data, i, &rel)) { + rel = elf_rel_by_idx(data, i); + if (!rel) { pr_warn(".maps relo #%d: failed to get ELF relo\n", i); return -LIBBPF_ERRNO__FORMAT; } - if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) { + + sym = elf_sym_by_idx(obj, ELF64_R_SYM(rel->r_info)); + if (!sym) { pr_warn(".maps relo #%d: symbol %zx not found\n", - i, (size_t)GELF_R_SYM(rel.r_info)); + i, (size_t)ELF64_R_SYM(rel->r_info)); return -LIBBPF_ERRNO__FORMAT; } - name = elf_sym_str(obj, sym.st_name) ?: "<?>"; - if (sym.st_shndx != obj->efile.btf_maps_shndx) { - pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n", - i, name); - return -LIBBPF_ERRNO__RELOC; - } + name = elf_sym_str(obj, sym->st_name) ?: "<?>"; - pr_debug(".maps relo #%d: for %zd value %zd rel.r_offset %zu name %d ('%s')\n", - i, (ssize_t)(rel.r_info >> 32), (size_t)sym.st_value, - (size_t)rel.r_offset, sym.st_name, name); + pr_debug(".maps relo #%d: for %zd value %zd rel->r_offset %zu name %d ('%s')\n", + i, (ssize_t)(rel->r_info >> 32), (size_t)sym->st_value, + (size_t)rel->r_offset, sym->st_name, name); for (j = 0; j < obj->nr_maps; j++) { map = &obj->maps[j]; @@ -6462,29 +7071,55 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj, continue; vi = btf_var_secinfos(sec) + map->btf_var_idx; - if (vi->offset <= rel.r_offset && - rel.r_offset + bpf_ptr_sz <= vi->offset + vi->size) + if (vi->offset <= rel->r_offset && + rel->r_offset + bpf_ptr_sz <= vi->offset + vi->size) break; } if (j == obj->nr_maps) { - pr_warn(".maps relo #%d: cannot find map '%s' at rel.r_offset %zu\n", - i, name, (size_t)rel.r_offset); + pr_warn(".maps relo #%d: cannot find map '%s' at rel->r_offset %zu\n", + i, name, (size_t)rel->r_offset); return -EINVAL; } - if (!bpf_map_type__is_map_in_map(map->def.type)) - return -EINVAL; - if (map->def.type == BPF_MAP_TYPE_HASH_OF_MAPS && - map->def.key_size != sizeof(int)) { - pr_warn(".maps relo #%d: hash-of-maps '%s' should have key size %zu.\n", - i, map->name, sizeof(int)); + is_map_in_map = bpf_map_type__is_map_in_map(map->def.type); + is_prog_array = map->def.type == BPF_MAP_TYPE_PROG_ARRAY; + type = is_map_in_map ? "map" : "prog"; + if (is_map_in_map) { + if (sym->st_shndx != obj->efile.btf_maps_shndx) { + pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n", + i, name); + return -LIBBPF_ERRNO__RELOC; + } + if (map->def.type == BPF_MAP_TYPE_HASH_OF_MAPS && + map->def.key_size != sizeof(int)) { + pr_warn(".maps relo #%d: hash-of-maps '%s' should have key size %zu.\n", + i, map->name, sizeof(int)); + return -EINVAL; + } + targ_map = bpf_object__find_map_by_name(obj, name); + if (!targ_map) { + pr_warn(".maps relo #%d: '%s' isn't a valid map reference\n", + i, name); + return -ESRCH; + } + } else if (is_prog_array) { + targ_prog = bpf_object__find_program_by_name(obj, name); + if (!targ_prog) { + pr_warn(".maps relo #%d: '%s' isn't a valid program reference\n", + i, name); + return -ESRCH; + } + if (targ_prog->sec_idx != sym->st_shndx || + targ_prog->sec_insn_off * 8 != sym->st_value || + prog_is_subprog(obj, targ_prog)) { + pr_warn(".maps relo #%d: '%s' isn't an entry-point program\n", + i, name); + return -LIBBPF_ERRNO__RELOC; + } + } else { return -EINVAL; } - targ_map = bpf_object__find_map_by_name(obj, name); - if (!targ_map) - return -ESRCH; - var = btf__type_by_id(obj->btf, vi->type); def = skip_mods_and_typedefs(obj->btf, var->type, NULL); if (btf_vlen(def) == 0) @@ -6495,10 +7130,10 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj, return -EINVAL; moff = btf_member_bit_offset(def, btf_vlen(def) - 1) / 8; - if (rel.r_offset - vi->offset < moff) + if (rel->r_offset - vi->offset < moff) return -EINVAL; - moff = rel.r_offset - vi->offset - moff; + moff = rel->r_offset - vi->offset - moff; /* here we use BPF pointer size, which is always 64 bit, as we * are parsing ELF that was built for BPF target */ @@ -6515,45 +7150,38 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj, (new_sz - map->init_slots_sz) * host_ptr_sz); map->init_slots_sz = new_sz; } - map->init_slots[moff] = targ_map; + map->init_slots[moff] = is_map_in_map ? (void *)targ_map : (void *)targ_prog; - pr_debug(".maps relo #%d: map '%s' slot [%d] points to map '%s'\n", - i, map->name, moff, name); + pr_debug(".maps relo #%d: map '%s' slot [%d] points to %s '%s'\n", + i, map->name, moff, type, name); } return 0; } -static int cmp_relocs(const void *_a, const void *_b) -{ - const struct reloc_desc *a = _a; - const struct reloc_desc *b = _b; - - if (a->insn_idx != b->insn_idx) - return a->insn_idx < b->insn_idx ? -1 : 1; - - /* no two relocations should have the same insn_idx, but ... */ - if (a->type != b->type) - return a->type < b->type ? -1 : 1; - - return 0; -} - static int bpf_object__collect_relos(struct bpf_object *obj) { int i, err; - for (i = 0; i < obj->efile.nr_reloc_sects; i++) { - GElf_Shdr *shdr = &obj->efile.reloc_sects[i].shdr; - Elf_Data *data = obj->efile.reloc_sects[i].data; - int idx = shdr->sh_info; + for (i = 0; i < obj->efile.sec_cnt; i++) { + struct elf_sec_desc *sec_desc = &obj->efile.secs[i]; + Elf64_Shdr *shdr; + Elf_Data *data; + int idx; - if (shdr->sh_type != SHT_REL) { + if (sec_desc->sec_type != SEC_RELO) + continue; + + shdr = sec_desc->shdr; + data = sec_desc->data; + idx = shdr->sh_info; + + if (shdr->sh_type != SHT_REL || idx < 0 || idx >= obj->efile.sec_cnt) { pr_warn("internal error at %d\n", __LINE__); return -LIBBPF_ERRNO__INTERNAL; } - if (idx == obj->efile.st_ops_shndx) + if (obj->efile.secs[idx].sec_type == SEC_ST_OPS) err = bpf_object__collect_st_ops_relos(obj, shdr, data); else if (idx == obj->efile.btf_maps_shndx) err = bpf_object__collect_map_relos(obj, shdr, data); @@ -6563,14 +7191,7 @@ static int bpf_object__collect_relos(struct bpf_object *obj) return err; } - for (i = 0; i < obj->nr_programs; i++) { - struct bpf_program *p = &obj->programs[i]; - - if (!p->nr_reloc) - continue; - - qsort(p->reloc_desc, p->nr_reloc, sizeof(*p->reloc_desc), cmp_relocs); - } + bpf_object__sort_relos(obj); return 0; } @@ -6587,12 +7208,15 @@ static bool insn_is_helper_call(struct bpf_insn *insn, enum bpf_func_id *func_id return false; } -static int bpf_object__sanitize_prog(struct bpf_object* obj, struct bpf_program *prog) +static int bpf_object__sanitize_prog(struct bpf_object *obj, struct bpf_program *prog) { struct bpf_insn *insn = prog->insns; enum bpf_func_id func_id; int i; + if (obj->gen_loader) + return 0; + for (i = 0; i < prog->insns_cnt; i++, insn++) { if (!insn_is_helper_call(insn, &func_id)) continue; @@ -6604,12 +7228,12 @@ static int bpf_object__sanitize_prog(struct bpf_object* obj, struct bpf_program switch (func_id) { case BPF_FUNC_probe_read_kernel: case BPF_FUNC_probe_read_user: - if (!kernel_supports(FEAT_PROBE_READ_KERN)) + if (!kernel_supports(obj, FEAT_PROBE_READ_KERN)) insn->imm = BPF_FUNC_probe_read; break; case BPF_FUNC_probe_read_kernel_str: case BPF_FUNC_probe_read_user_str: - if (!kernel_supports(FEAT_PROBE_READ_KERN)) + if (!kernel_supports(obj, FEAT_PROBE_READ_KERN)) insn->imm = BPF_FUNC_probe_read_str; break; default: @@ -6619,46 +7243,108 @@ static int bpf_object__sanitize_prog(struct bpf_object* obj, struct bpf_program return 0; } -static int -load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, - char *license, __u32 kern_version, int *pfd) +static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attach_name, + int *btf_obj_fd, int *btf_type_id); + +/* this is called as prog->sec_def->prog_prepare_load_fn for libbpf-supported sec_defs */ +static int libbpf_prepare_prog_load(struct bpf_program *prog, + struct bpf_prog_load_opts *opts, long cookie) +{ + enum sec_def_flags def = cookie; + + /* old kernels might not support specifying expected_attach_type */ + if ((def & SEC_EXP_ATTACH_OPT) && !kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE)) + opts->expected_attach_type = 0; + + if (def & SEC_SLEEPABLE) + opts->prog_flags |= BPF_F_SLEEPABLE; + + if (prog->type == BPF_PROG_TYPE_XDP && (def & SEC_XDP_FRAGS)) + opts->prog_flags |= BPF_F_XDP_HAS_FRAGS; + + /* special check for usdt to use uprobe_multi link */ + if ((def & SEC_USDT) && kernel_supports(prog->obj, FEAT_UPROBE_MULTI_LINK)) + prog->expected_attach_type = BPF_TRACE_UPROBE_MULTI; + + if ((def & SEC_ATTACH_BTF) && !prog->attach_btf_id) { + int btf_obj_fd = 0, btf_type_id = 0, err; + const char *attach_name; + + attach_name = strchr(prog->sec_name, '/'); + if (!attach_name) { + /* if BPF program is annotated with just SEC("fentry") + * (or similar) without declaratively specifying + * target, then it is expected that target will be + * specified with bpf_program__set_attach_target() at + * runtime before BPF object load step. If not, then + * there is nothing to load into the kernel as BPF + * verifier won't be able to validate BPF program + * correctness anyways. + */ + pr_warn("prog '%s': no BTF-based attach target is specified, use bpf_program__set_attach_target()\n", + prog->name); + return -EINVAL; + } + attach_name++; /* skip over / */ + + err = libbpf_find_attach_btf_id(prog, attach_name, &btf_obj_fd, &btf_type_id); + if (err) + return err; + + /* cache resolved BTF FD and BTF type ID in the prog */ + prog->attach_btf_obj_fd = btf_obj_fd; + prog->attach_btf_id = btf_type_id; + + /* but by now libbpf common logic is not utilizing + * prog->atach_btf_obj_fd/prog->attach_btf_id anymore because + * this callback is called after opts were populated by + * libbpf, so this callback has to update opts explicitly here + */ + opts->attach_btf_obj_fd = btf_obj_fd; + opts->attach_btf_id = btf_type_id; + } + return 0; +} + +static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_sz); + +static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog, + struct bpf_insn *insns, int insns_cnt, + const char *license, __u32 kern_version, int *prog_fd) { - struct bpf_load_program_attr load_attr; + LIBBPF_OPTS(bpf_prog_load_opts, load_attr); + const char *prog_name = NULL; char *cp, errmsg[STRERR_BUFSIZE]; size_t log_buf_size = 0; - char *log_buf = NULL; - int btf_fd, ret; + char *log_buf = NULL, *tmp; + int btf_fd, ret, err; + bool own_log_buf = true; + __u32 log_level = prog->log_level; + + if (prog->type == BPF_PROG_TYPE_UNSPEC) { + /* + * The program type must be set. Most likely we couldn't find a proper + * section definition at load time, and thus we didn't infer the type. + */ + pr_warn("prog '%s': missing BPF prog type, check ELF section name '%s'\n", + prog->name, prog->sec_name); + return -EINVAL; + } if (!insns || !insns_cnt) return -EINVAL; - memset(&load_attr, 0, sizeof(struct bpf_load_program_attr)); - load_attr.prog_type = prog->type; - /* old kernels might not support specifying expected_attach_type */ - if (!kernel_supports(FEAT_EXP_ATTACH_TYPE) && prog->sec_def && - prog->sec_def->is_exp_attach_type_optional) - load_attr.expected_attach_type = 0; - else - load_attr.expected_attach_type = prog->expected_attach_type; - if (kernel_supports(FEAT_PROG_NAME)) - load_attr.name = prog->name; - load_attr.insns = insns; - load_attr.insns_cnt = insns_cnt; - load_attr.license = license; - if (prog->type == BPF_PROG_TYPE_STRUCT_OPS || - prog->type == BPF_PROG_TYPE_LSM) { - load_attr.attach_btf_id = prog->attach_btf_id; - } else if (prog->type == BPF_PROG_TYPE_TRACING || - prog->type == BPF_PROG_TYPE_EXT) { - load_attr.attach_prog_fd = prog->attach_prog_fd; - load_attr.attach_btf_id = prog->attach_btf_id; - } else { - load_attr.kern_version = kern_version; - load_attr.prog_ifindex = prog->prog_ifindex; - } + if (kernel_supports(obj, FEAT_PROG_NAME)) + prog_name = prog->name; + load_attr.attach_prog_fd = prog->attach_prog_fd; + load_attr.attach_btf_obj_fd = prog->attach_btf_obj_fd; + load_attr.attach_btf_id = prog->attach_btf_id; + load_attr.kern_version = kern_version; + load_attr.prog_ifindex = prog->prog_ifindex; + /* specify func_info/line_info only if kernel supports them */ - btf_fd = bpf_object__btf_fd(prog->obj); - if (btf_fd >= 0 && kernel_supports(FEAT_BTF_FUNC)) { + btf_fd = btf__fd(obj->btf); + if (btf_fd >= 0 && kernel_supports(obj, FEAT_BTF_FUNC)) { load_attr.prog_btf_fd = btf_fd; load_attr.func_info = prog->func_info; load_attr.func_info_rec_size = prog->func_info_rec_size; @@ -6667,170 +7353,380 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, load_attr.line_info_rec_size = prog->line_info_rec_size; load_attr.line_info_cnt = prog->line_info_cnt; } - load_attr.log_level = prog->log_level; + load_attr.log_level = log_level; load_attr.prog_flags = prog->prog_flags; + load_attr.fd_array = obj->fd_array; -retry_load: - if (log_buf_size) { - log_buf = malloc(log_buf_size); - if (!log_buf) - return -ENOMEM; + load_attr.token_fd = obj->token_fd; + if (obj->token_fd) + load_attr.prog_flags |= BPF_F_TOKEN_FD; - *log_buf = 0; + /* adjust load_attr if sec_def provides custom preload callback */ + if (prog->sec_def && prog->sec_def->prog_prepare_load_fn) { + err = prog->sec_def->prog_prepare_load_fn(prog, &load_attr, prog->sec_def->cookie); + if (err < 0) { + pr_warn("prog '%s': failed to prepare load attributes: %d\n", + prog->name, err); + return err; + } + insns = prog->insns; + insns_cnt = prog->insns_cnt; } - ret = bpf_load_program_xattr(&load_attr, log_buf, log_buf_size); + /* allow prog_prepare_load_fn to change expected_attach_type */ + load_attr.expected_attach_type = prog->expected_attach_type; + if (obj->gen_loader) { + bpf_gen__prog_load(obj->gen_loader, prog->type, prog->name, + license, insns, insns_cnt, &load_attr, + prog - obj->programs); + *prog_fd = -1; + return 0; + } + +retry_load: + /* if log_level is zero, we don't request logs initially even if + * custom log_buf is specified; if the program load fails, then we'll + * bump log_level to 1 and use either custom log_buf or we'll allocate + * our own and retry the load to get details on what failed + */ + if (log_level) { + if (prog->log_buf) { + log_buf = prog->log_buf; + log_buf_size = prog->log_size; + own_log_buf = false; + } else if (obj->log_buf) { + log_buf = obj->log_buf; + log_buf_size = obj->log_size; + own_log_buf = false; + } else { + log_buf_size = max((size_t)BPF_LOG_BUF_SIZE, log_buf_size * 2); + tmp = realloc(log_buf, log_buf_size); + if (!tmp) { + ret = -ENOMEM; + goto out; + } + log_buf = tmp; + log_buf[0] = '\0'; + own_log_buf = true; + } + } + + load_attr.log_buf = log_buf; + load_attr.log_size = log_buf_size; + load_attr.log_level = log_level; + + ret = bpf_prog_load(prog->type, prog_name, license, insns, insns_cnt, &load_attr); if (ret >= 0) { - if (log_buf && load_attr.log_level) - pr_debug("verifier log:\n%s", log_buf); - - if (prog->obj->rodata_map_idx >= 0 && - kernel_supports(FEAT_PROG_BIND_MAP)) { - struct bpf_map *rodata_map = - &prog->obj->maps[prog->obj->rodata_map_idx]; - - if (bpf_prog_bind_map(ret, bpf_map__fd(rodata_map), NULL)) { - cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); - pr_warn("prog '%s': failed to bind .rodata map: %s\n", - prog->name, cp); - /* Don't fail hard if can't bind rodata. */ + if (log_level && own_log_buf) { + pr_debug("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n", + prog->name, log_buf); + } + + if (obj->has_rodata && kernel_supports(obj, FEAT_PROG_BIND_MAP)) { + struct bpf_map *map; + int i; + + for (i = 0; i < obj->nr_maps; i++) { + map = &prog->obj->maps[i]; + if (map->libbpf_type != LIBBPF_MAP_RODATA) + continue; + + if (bpf_prog_bind_map(ret, map->fd, NULL)) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warn("prog '%s': failed to bind map '%s': %s\n", + prog->name, map->real_name, cp); + /* Don't fail hard if can't bind rodata. */ + } } } - *pfd = ret; + *prog_fd = ret; ret = 0; goto out; } - if (!log_buf || errno == ENOSPC) { - log_buf_size = max((size_t)BPF_LOG_BUF_SIZE, - log_buf_size << 1); - - free(log_buf); + if (log_level == 0) { + log_level = 1; goto retry_load; } - ret = errno ? -errno : -LIBBPF_ERRNO__LOAD; + /* On ENOSPC, increase log buffer size and retry, unless custom + * log_buf is specified. + * Be careful to not overflow u32, though. Kernel's log buf size limit + * isn't part of UAPI so it can always be bumped to full 4GB. So don't + * multiply by 2 unless we are sure we'll fit within 32 bits. + * Currently, we'll get -EINVAL when we reach (UINT_MAX >> 2). + */ + if (own_log_buf && errno == ENOSPC && log_buf_size <= UINT_MAX / 2) + goto retry_load; + + ret = -errno; + + /* post-process verifier log to improve error descriptions */ + fixup_verifier_log(prog, log_buf, log_buf_size); + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); - pr_warn("load bpf program failed: %s\n", cp); + pr_warn("prog '%s': BPF program load failed: %s\n", prog->name, cp); pr_perm_msg(ret); - if (log_buf && log_buf[0] != '\0') { - ret = -LIBBPF_ERRNO__VERIFY; - pr_warn("-- BEGIN DUMP LOG ---\n"); - pr_warn("\n%s\n", log_buf); - pr_warn("-- END LOG --\n"); - } else if (load_attr.insns_cnt >= BPF_MAXINSNS) { - pr_warn("Program too large (%zu insns), at most %d insns\n", - load_attr.insns_cnt, BPF_MAXINSNS); - ret = -LIBBPF_ERRNO__PROG2BIG; - } else if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) { - /* Wrong program type? */ - int fd; - - load_attr.prog_type = BPF_PROG_TYPE_KPROBE; - load_attr.expected_attach_type = 0; - fd = bpf_load_program_xattr(&load_attr, NULL, 0); - if (fd >= 0) { - close(fd); - ret = -LIBBPF_ERRNO__PROGTYPE; - goto out; - } + if (own_log_buf && log_buf && log_buf[0] != '\0') { + pr_warn("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n", + prog->name, log_buf); } out: - free(log_buf); + if (own_log_buf) + free(log_buf); return ret; } -static int libbpf_find_attach_btf_id(struct bpf_program *prog); - -int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) +static char *find_prev_line(char *buf, char *cur) { - int err = 0, fd, i, btf_id; + char *p; - if (prog->obj->loaded) { - pr_warn("prog '%s': can't load after object was loaded\n", prog->name); - return -EINVAL; - } + if (cur == buf) /* end of a log buf */ + return NULL; - if ((prog->type == BPF_PROG_TYPE_TRACING || - prog->type == BPF_PROG_TYPE_LSM || - prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) { - btf_id = libbpf_find_attach_btf_id(prog); - if (btf_id <= 0) - return btf_id; - prog->attach_btf_id = btf_id; - } + p = cur - 1; + while (p - 1 >= buf && *(p - 1) != '\n') + p--; - if (prog->instances.nr < 0 || !prog->instances.fds) { - if (prog->preprocessor) { - pr_warn("Internal error: can't load program '%s'\n", - prog->name); - return -LIBBPF_ERRNO__INTERNAL; - } + return p; +} - prog->instances.fds = malloc(sizeof(int)); - if (!prog->instances.fds) { - pr_warn("Not enough memory for BPF fds\n"); - return -ENOMEM; +static void patch_log(char *buf, size_t buf_sz, size_t log_sz, + char *orig, size_t orig_sz, const char *patch) +{ + /* size of the remaining log content to the right from the to-be-replaced part */ + size_t rem_sz = (buf + log_sz) - (orig + orig_sz); + size_t patch_sz = strlen(patch); + + if (patch_sz != orig_sz) { + /* If patch line(s) are longer than original piece of verifier log, + * shift log contents by (patch_sz - orig_sz) bytes to the right + * starting from after to-be-replaced part of the log. + * + * If patch line(s) are shorter than original piece of verifier log, + * shift log contents by (orig_sz - patch_sz) bytes to the left + * starting from after to-be-replaced part of the log + * + * We need to be careful about not overflowing available + * buf_sz capacity. If that's the case, we'll truncate the end + * of the original log, as necessary. + */ + if (patch_sz > orig_sz) { + if (orig + patch_sz >= buf + buf_sz) { + /* patch is big enough to cover remaining space completely */ + patch_sz -= (orig + patch_sz) - (buf + buf_sz) + 1; + rem_sz = 0; + } else if (patch_sz - orig_sz > buf_sz - log_sz) { + /* patch causes part of remaining log to be truncated */ + rem_sz -= (patch_sz - orig_sz) - (buf_sz - log_sz); + } } - prog->instances.nr = 1; - prog->instances.fds[0] = -1; + /* shift remaining log to the right by calculated amount */ + memmove(orig + patch_sz, orig + orig_sz, rem_sz); } - if (!prog->preprocessor) { - if (prog->instances.nr != 1) { - pr_warn("prog '%s': inconsistent nr(%d) != 1\n", - prog->name, prog->instances.nr); + memcpy(orig, patch, patch_sz); +} + +static void fixup_log_failed_core_relo(struct bpf_program *prog, + char *buf, size_t buf_sz, size_t log_sz, + char *line1, char *line2, char *line3) +{ + /* Expected log for failed and not properly guarded CO-RE relocation: + * line1 -> 123: (85) call unknown#195896080 + * line2 -> invalid func unknown#195896080 + * line3 -> <anything else or end of buffer> + * + * "123" is the index of the instruction that was poisoned. We extract + * instruction index to find corresponding CO-RE relocation and + * replace this part of the log with more relevant information about + * failed CO-RE relocation. + */ + const struct bpf_core_relo *relo; + struct bpf_core_spec spec; + char patch[512], spec_buf[256]; + int insn_idx, err, spec_len; + + if (sscanf(line1, "%d: (%*d) call unknown#195896080\n", &insn_idx) != 1) + return; + + relo = find_relo_core(prog, insn_idx); + if (!relo) + return; + + err = bpf_core_parse_spec(prog->name, prog->obj->btf, relo, &spec); + if (err) + return; + + spec_len = bpf_core_format_spec(spec_buf, sizeof(spec_buf), &spec); + snprintf(patch, sizeof(patch), + "%d: <invalid CO-RE relocation>\n" + "failed to resolve CO-RE relocation %s%s\n", + insn_idx, spec_buf, spec_len >= sizeof(spec_buf) ? "..." : ""); + + patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch); +} + +static void fixup_log_missing_map_load(struct bpf_program *prog, + char *buf, size_t buf_sz, size_t log_sz, + char *line1, char *line2, char *line3) +{ + /* Expected log for failed and not properly guarded map reference: + * line1 -> 123: (85) call unknown#2001000345 + * line2 -> invalid func unknown#2001000345 + * line3 -> <anything else or end of buffer> + * + * "123" is the index of the instruction that was poisoned. + * "345" in "2001000345" is a map index in obj->maps to fetch map name. + */ + struct bpf_object *obj = prog->obj; + const struct bpf_map *map; + int insn_idx, map_idx; + char patch[128]; + + if (sscanf(line1, "%d: (%*d) call unknown#%d\n", &insn_idx, &map_idx) != 2) + return; + + map_idx -= POISON_LDIMM64_MAP_BASE; + if (map_idx < 0 || map_idx >= obj->nr_maps) + return; + map = &obj->maps[map_idx]; + + snprintf(patch, sizeof(patch), + "%d: <invalid BPF map reference>\n" + "BPF map '%s' is referenced but wasn't created\n", + insn_idx, map->name); + + patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch); +} + +static void fixup_log_missing_kfunc_call(struct bpf_program *prog, + char *buf, size_t buf_sz, size_t log_sz, + char *line1, char *line2, char *line3) +{ + /* Expected log for failed and not properly guarded kfunc call: + * line1 -> 123: (85) call unknown#2002000345 + * line2 -> invalid func unknown#2002000345 + * line3 -> <anything else or end of buffer> + * + * "123" is the index of the instruction that was poisoned. + * "345" in "2002000345" is an extern index in obj->externs to fetch kfunc name. + */ + struct bpf_object *obj = prog->obj; + const struct extern_desc *ext; + int insn_idx, ext_idx; + char patch[128]; + + if (sscanf(line1, "%d: (%*d) call unknown#%d\n", &insn_idx, &ext_idx) != 2) + return; + + ext_idx -= POISON_CALL_KFUNC_BASE; + if (ext_idx < 0 || ext_idx >= obj->nr_extern) + return; + ext = &obj->externs[ext_idx]; + + snprintf(patch, sizeof(patch), + "%d: <invalid kfunc call>\n" + "kfunc '%s' is referenced but wasn't resolved\n", + insn_idx, ext->name); + + patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch); +} + +static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_sz) +{ + /* look for familiar error patterns in last N lines of the log */ + const size_t max_last_line_cnt = 10; + char *prev_line, *cur_line, *next_line; + size_t log_sz; + int i; + + if (!buf) + return; + + log_sz = strlen(buf) + 1; + next_line = buf + log_sz - 1; + + for (i = 0; i < max_last_line_cnt; i++, next_line = cur_line) { + cur_line = find_prev_line(buf, next_line); + if (!cur_line) + return; + + if (str_has_pfx(cur_line, "invalid func unknown#195896080\n")) { + prev_line = find_prev_line(buf, cur_line); + if (!prev_line) + continue; + + /* failed CO-RE relocation case */ + fixup_log_failed_core_relo(prog, buf, buf_sz, log_sz, + prev_line, cur_line, next_line); + return; + } else if (str_has_pfx(cur_line, "invalid func unknown#"POISON_LDIMM64_MAP_PFX)) { + prev_line = find_prev_line(buf, cur_line); + if (!prev_line) + continue; + + /* reference to uncreated BPF map */ + fixup_log_missing_map_load(prog, buf, buf_sz, log_sz, + prev_line, cur_line, next_line); + return; + } else if (str_has_pfx(cur_line, "invalid func unknown#"POISON_CALL_KFUNC_PFX)) { + prev_line = find_prev_line(buf, cur_line); + if (!prev_line) + continue; + + /* reference to unresolved kfunc */ + fixup_log_missing_kfunc_call(prog, buf, buf_sz, log_sz, + prev_line, cur_line, next_line); + return; } - err = load_program(prog, prog->insns, prog->insns_cnt, - license, kern_ver, &fd); - if (!err) - prog->instances.fds[0] = fd; - goto out; } +} - for (i = 0; i < prog->instances.nr; i++) { - struct bpf_prog_prep_result result; - bpf_program_prep_t preprocessor = prog->preprocessor; +static int bpf_program_record_relos(struct bpf_program *prog) +{ + struct bpf_object *obj = prog->obj; + int i; - memset(&result, 0, sizeof(result)); - err = preprocessor(prog, i, prog->insns, - prog->insns_cnt, &result); - if (err) { - pr_warn("Preprocessing the %dth instance of program '%s' failed\n", - i, prog->name); - goto out; - } + for (i = 0; i < prog->nr_reloc; i++) { + struct reloc_desc *relo = &prog->reloc_desc[i]; + struct extern_desc *ext = &obj->externs[relo->ext_idx]; + int kind; - if (!result.new_insn_ptr || !result.new_insn_cnt) { - pr_debug("Skip loading the %dth instance of program '%s'\n", - i, prog->name); - prog->instances.fds[i] = -1; - if (result.pfd) - *result.pfd = -1; - continue; + switch (relo->type) { + case RELO_EXTERN_LD64: + if (ext->type != EXT_KSYM) + continue; + kind = btf_is_var(btf__type_by_id(obj->btf, ext->btf_id)) ? + BTF_KIND_VAR : BTF_KIND_FUNC; + bpf_gen__record_extern(obj->gen_loader, ext->name, + ext->is_weak, !ext->ksym.type_id, + true, kind, relo->insn_idx); + break; + case RELO_EXTERN_CALL: + bpf_gen__record_extern(obj->gen_loader, ext->name, + ext->is_weak, false, false, BTF_KIND_FUNC, + relo->insn_idx); + break; + case RELO_CORE: { + struct bpf_core_relo cr = { + .insn_off = relo->insn_idx * 8, + .type_id = relo->core_relo->type_id, + .access_str_off = relo->core_relo->access_str_off, + .kind = relo->core_relo->kind, + }; + + bpf_gen__record_relo_core(obj->gen_loader, &cr); + break; } - - err = load_program(prog, result.new_insn_ptr, - result.new_insn_cnt, license, kern_ver, &fd); - if (err) { - pr_warn("Loading the %dth instance of program '%s' failed\n", - i, prog->name); - goto out; + default: + continue; } - - if (result.pfd) - *result.pfd = fd; - prog->instances.fds[i] = fd; } -out: - if (err) - pr_warn("failed to load program '%s'\n", prog->name); - zfree(&prog->insns); - prog->insns_cnt = 0; - return err; + return 0; } static int @@ -6851,29 +7747,72 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level) prog = &obj->programs[i]; if (prog_is_subprog(obj, prog)) continue; - if (!prog->load) { + if (!prog->autoload) { pr_debug("prog '%s': skipped loading\n", prog->name); continue; } prog->log_level |= log_level; - err = bpf_program__load(prog, obj->license, obj->kern_version); - if (err) + + if (obj->gen_loader) + bpf_program_record_relos(prog); + + err = bpf_object_load_prog(obj, prog, prog->insns, prog->insns_cnt, + obj->license, obj->kern_version, &prog->fd); + if (err) { + pr_warn("prog '%s': failed to load: %d\n", prog->name, err); return err; + } } + + bpf_object__free_relocs(obj); return 0; } static const struct bpf_sec_def *find_sec_def(const char *sec_name); -static struct bpf_object * -__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz, - const struct bpf_object_open_opts *opts) +static int bpf_object_init_progs(struct bpf_object *obj, const struct bpf_object_open_opts *opts) { - const char *obj_name, *kconfig; struct bpf_program *prog; + int err; + + bpf_object__for_each_program(prog, obj) { + prog->sec_def = find_sec_def(prog->sec_name); + if (!prog->sec_def) { + /* couldn't guess, but user might manually specify */ + pr_debug("prog '%s': unrecognized ELF section name '%s'\n", + prog->name, prog->sec_name); + continue; + } + + prog->type = prog->sec_def->prog_type; + prog->expected_attach_type = prog->sec_def->expected_attach_type; + + /* sec_def can have custom callback which should be called + * after bpf_program is initialized to adjust its properties + */ + if (prog->sec_def->prog_setup_fn) { + err = prog->sec_def->prog_setup_fn(prog, prog->sec_def->cookie); + if (err < 0) { + pr_warn("prog '%s': failed to initialize: %d\n", + prog->name, err); + return err; + } + } + } + + return 0; +} + +static struct bpf_object *bpf_object_open(const char *path, const void *obj_buf, size_t obj_buf_sz, + const struct bpf_object_open_opts *opts) +{ + const char *obj_name, *kconfig, *btf_tmp_path, *token_path; struct bpf_object *obj; char tmp_name[64]; int err; + char *log_buf; + size_t log_size; + __u32 log_level; if (elf_version(EV_CURRENT) == EV_NONE) { pr_warn("failed to init libelf for %s\n", @@ -6896,44 +7835,74 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz, pr_debug("loading object '%s' from buffer\n", obj_name); } + log_buf = OPTS_GET(opts, kernel_log_buf, NULL); + log_size = OPTS_GET(opts, kernel_log_size, 0); + log_level = OPTS_GET(opts, kernel_log_level, 0); + if (log_size > UINT_MAX) + return ERR_PTR(-EINVAL); + if (log_size && !log_buf) + return ERR_PTR(-EINVAL); + + token_path = OPTS_GET(opts, bpf_token_path, NULL); + /* if user didn't specify bpf_token_path explicitly, check if + * LIBBPF_BPF_TOKEN_PATH envvar was set and treat it as bpf_token_path + * option + */ + if (!token_path) + token_path = getenv("LIBBPF_BPF_TOKEN_PATH"); + if (token_path && strlen(token_path) >= PATH_MAX) + return ERR_PTR(-ENAMETOOLONG); + obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name); if (IS_ERR(obj)) return obj; + obj->log_buf = log_buf; + obj->log_size = log_size; + obj->log_level = log_level; + + if (token_path) { + obj->token_path = strdup(token_path); + if (!obj->token_path) { + err = -ENOMEM; + goto out; + } + } + + btf_tmp_path = OPTS_GET(opts, btf_custom_path, NULL); + if (btf_tmp_path) { + if (strlen(btf_tmp_path) >= PATH_MAX) { + err = -ENAMETOOLONG; + goto out; + } + obj->btf_custom_path = strdup(btf_tmp_path); + if (!obj->btf_custom_path) { + err = -ENOMEM; + goto out; + } + } + kconfig = OPTS_GET(opts, kconfig, NULL); if (kconfig) { obj->kconfig = strdup(kconfig); - if (!obj->kconfig) - return ERR_PTR(-ENOMEM); + if (!obj->kconfig) { + err = -ENOMEM; + goto out; + } } err = bpf_object__elf_init(obj); err = err ? : bpf_object__check_endianness(obj); err = err ? : bpf_object__elf_collect(obj); err = err ? : bpf_object__collect_externs(obj); - err = err ? : bpf_object__finalize_btf(obj); + err = err ? : bpf_object_fixup_btf(obj); err = err ? : bpf_object__init_maps(obj, opts); + err = err ? : bpf_object_init_progs(obj, opts); err = err ? : bpf_object__collect_relos(obj); if (err) goto out; - bpf_object__elf_finish(obj); - - bpf_object__for_each_program(prog, obj) { - prog->sec_def = find_sec_def(prog->sec_name); - if (!prog->sec_def) - /* couldn't guess, but user might manually specify */ - continue; - - if (prog->sec_def->is_sleepable) - prog->prog_flags |= BPF_F_SLEEPABLE; - bpf_program__set_type(prog, prog->sec_def->prog_type); - bpf_program__set_expected_attach_type(prog, - prog->sec_def->expected_attach_type); - if (prog->sec_def->prog_type == BPF_PROG_TYPE_TRACING || - prog->sec_def->prog_type == BPF_PROG_TYPE_EXT) - prog->attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0); - } + bpf_object__elf_finish(obj); return obj; out: @@ -6941,80 +7910,38 @@ out: return ERR_PTR(err); } -static struct bpf_object * -__bpf_object__open_xattr(struct bpf_object_open_attr *attr, int flags) -{ - DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts, - .relaxed_maps = flags & MAPS_RELAX_COMPAT, - ); - - /* param validation */ - if (!attr->file) - return NULL; - - pr_debug("loading %s\n", attr->file); - return __bpf_object__open(attr->file, NULL, 0, &opts); -} - -struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr) -{ - return __bpf_object__open_xattr(attr, 0); -} - -struct bpf_object *bpf_object__open(const char *path) -{ - struct bpf_object_open_attr attr = { - .file = path, - .prog_type = BPF_PROG_TYPE_UNSPEC, - }; - - return bpf_object__open_xattr(&attr); -} - struct bpf_object * bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts) { if (!path) - return ERR_PTR(-EINVAL); + return libbpf_err_ptr(-EINVAL); pr_debug("loading %s\n", path); - return __bpf_object__open(path, NULL, 0, opts); + return libbpf_ptr(bpf_object_open(path, NULL, 0, opts)); } -struct bpf_object * -bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz, - const struct bpf_object_open_opts *opts) +struct bpf_object *bpf_object__open(const char *path) { - if (!obj_buf || obj_buf_sz == 0) - return ERR_PTR(-EINVAL); - - return __bpf_object__open(NULL, obj_buf, obj_buf_sz, opts); + return bpf_object__open_file(path, NULL); } struct bpf_object * -bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz, - const char *name) +bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz, + const struct bpf_object_open_opts *opts) { - DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts, - .object_name = name, - /* wrong default, but backwards-compatible */ - .relaxed_maps = true, - ); - - /* returning NULL is wrong, but backwards-compatible */ if (!obj_buf || obj_buf_sz == 0) - return NULL; + return libbpf_err_ptr(-EINVAL); - return bpf_object__open_mem(obj_buf, obj_buf_sz, &opts); + return libbpf_ptr(bpf_object_open(NULL, obj_buf, obj_buf_sz, opts)); } -int bpf_object__unload(struct bpf_object *obj) +static int bpf_object_unload(struct bpf_object *obj) { size_t i; if (!obj) - return -EINVAL; + return libbpf_err(-EINVAL); for (i = 0; i < obj->nr_maps; i++) { zclose(obj->maps[i].fd); @@ -7035,26 +7962,21 @@ static int bpf_object__sanitize_maps(struct bpf_object *obj) bpf_object__for_each_map(m, obj) { if (!bpf_map__is_internal(m)) continue; - if (!kernel_supports(FEAT_GLOBAL_DATA)) { - pr_warn("kernel doesn't support global data\n"); - return -ENOTSUP; - } - if (!kernel_supports(FEAT_ARRAY_MMAP)) - m->def.map_flags ^= BPF_F_MMAPABLE; + if (!kernel_supports(obj, FEAT_ARRAY_MMAP)) + m->def.map_flags &= ~BPF_F_MMAPABLE; } return 0; } -static int bpf_object__read_kallsyms_file(struct bpf_object *obj) +int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *ctx) { char sym_type, sym_name[500]; unsigned long long sym_addr; - struct extern_desc *ext; int ret, err = 0; FILE *f; - f = fopen("/proc/kallsyms", "r"); + f = fopen("/proc/kallsyms", "re"); if (!f) { err = -errno; pr_warn("failed to open /proc/kallsyms: %d\n", err); @@ -7069,88 +7991,234 @@ static int bpf_object__read_kallsyms_file(struct bpf_object *obj) if (ret != 3) { pr_warn("failed to read kallsyms entry: %d\n", ret); err = -EINVAL; - goto out; + break; } - ext = find_extern_by_name(obj, sym_name); - if (!ext || ext->type != EXT_KSYM) - continue; + err = cb(sym_addr, sym_type, sym_name, ctx); + if (err) + break; + } - if (ext->is_set && ext->ksym.addr != sym_addr) { - pr_warn("extern (ksym) '%s' resolution is ambiguous: 0x%llx or 0x%llx\n", - sym_name, ext->ksym.addr, sym_addr); - err = -EINVAL; - goto out; + fclose(f); + return err; +} + +static int kallsyms_cb(unsigned long long sym_addr, char sym_type, + const char *sym_name, void *ctx) +{ + struct bpf_object *obj = ctx; + const struct btf_type *t; + struct extern_desc *ext; + + ext = find_extern_by_name(obj, sym_name); + if (!ext || ext->type != EXT_KSYM) + return 0; + + t = btf__type_by_id(obj->btf, ext->btf_id); + if (!btf_is_var(t)) + return 0; + + if (ext->is_set && ext->ksym.addr != sym_addr) { + pr_warn("extern (ksym) '%s': resolution is ambiguous: 0x%llx or 0x%llx\n", + sym_name, ext->ksym.addr, sym_addr); + return -EINVAL; + } + if (!ext->is_set) { + ext->is_set = true; + ext->ksym.addr = sym_addr; + pr_debug("extern (ksym) '%s': set to 0x%llx\n", sym_name, sym_addr); + } + return 0; +} + +static int bpf_object__read_kallsyms_file(struct bpf_object *obj) +{ + return libbpf_kallsyms_parse(kallsyms_cb, obj); +} + +static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name, + __u16 kind, struct btf **res_btf, + struct module_btf **res_mod_btf) +{ + struct module_btf *mod_btf; + struct btf *btf; + int i, id, err; + + btf = obj->btf_vmlinux; + mod_btf = NULL; + id = btf__find_by_name_kind(btf, ksym_name, kind); + + if (id == -ENOENT) { + err = load_module_btfs(obj); + if (err) + return err; + + for (i = 0; i < obj->btf_module_cnt; i++) { + /* we assume module_btf's BTF FD is always >0 */ + mod_btf = &obj->btf_modules[i]; + btf = mod_btf->btf; + id = btf__find_by_name_kind_own(btf, ksym_name, kind); + if (id != -ENOENT) + break; } - if (!ext->is_set) { - ext->is_set = true; - ext->ksym.addr = sym_addr; - pr_debug("extern (ksym) %s=0x%llx\n", sym_name, sym_addr); + } + if (id <= 0) + return -ESRCH; + + *res_btf = btf; + *res_mod_btf = mod_btf; + return id; +} + +static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj, + struct extern_desc *ext) +{ + const struct btf_type *targ_var, *targ_type; + __u32 targ_type_id, local_type_id; + struct module_btf *mod_btf = NULL; + const char *targ_var_name; + struct btf *btf = NULL; + int id, err; + + id = find_ksym_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, &mod_btf); + if (id < 0) { + if (id == -ESRCH && ext->is_weak) + return 0; + pr_warn("extern (var ksym) '%s': not found in kernel BTF\n", + ext->name); + return id; + } + + /* find local type_id */ + local_type_id = ext->ksym.type_id; + + /* find target type_id */ + targ_var = btf__type_by_id(btf, id); + targ_var_name = btf__name_by_offset(btf, targ_var->name_off); + targ_type = skip_mods_and_typedefs(btf, targ_var->type, &targ_type_id); + + err = bpf_core_types_are_compat(obj->btf, local_type_id, + btf, targ_type_id); + if (err <= 0) { + const struct btf_type *local_type; + const char *targ_name, *local_name; + + local_type = btf__type_by_id(obj->btf, local_type_id); + local_name = btf__name_by_offset(obj->btf, local_type->name_off); + targ_name = btf__name_by_offset(btf, targ_type->name_off); + + pr_warn("extern (var ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n", + ext->name, local_type_id, + btf_kind_str(local_type), local_name, targ_type_id, + btf_kind_str(targ_type), targ_name); + return -EINVAL; + } + + ext->is_set = true; + ext->ksym.kernel_btf_obj_fd = mod_btf ? mod_btf->fd : 0; + ext->ksym.kernel_btf_id = id; + pr_debug("extern (var ksym) '%s': resolved to [%d] %s %s\n", + ext->name, id, btf_kind_str(targ_var), targ_var_name); + + return 0; +} + +static int bpf_object__resolve_ksym_func_btf_id(struct bpf_object *obj, + struct extern_desc *ext) +{ + int local_func_proto_id, kfunc_proto_id, kfunc_id; + struct module_btf *mod_btf = NULL; + const struct btf_type *kern_func; + struct btf *kern_btf = NULL; + int ret; + + local_func_proto_id = ext->ksym.type_id; + + kfunc_id = find_ksym_btf_id(obj, ext->essent_name ?: ext->name, BTF_KIND_FUNC, &kern_btf, + &mod_btf); + if (kfunc_id < 0) { + if (kfunc_id == -ESRCH && ext->is_weak) + return 0; + pr_warn("extern (func ksym) '%s': not found in kernel or module BTFs\n", + ext->name); + return kfunc_id; + } + + kern_func = btf__type_by_id(kern_btf, kfunc_id); + kfunc_proto_id = kern_func->type; + + ret = bpf_core_types_are_compat(obj->btf, local_func_proto_id, + kern_btf, kfunc_proto_id); + if (ret <= 0) { + if (ext->is_weak) + return 0; + + pr_warn("extern (func ksym) '%s': func_proto [%d] incompatible with %s [%d]\n", + ext->name, local_func_proto_id, + mod_btf ? mod_btf->name : "vmlinux", kfunc_proto_id); + return -EINVAL; + } + + /* set index for module BTF fd in fd_array, if unset */ + if (mod_btf && !mod_btf->fd_array_idx) { + /* insn->off is s16 */ + if (obj->fd_array_cnt == INT16_MAX) { + pr_warn("extern (func ksym) '%s': module BTF fd index %d too big to fit in bpf_insn offset\n", + ext->name, mod_btf->fd_array_idx); + return -E2BIG; } + /* Cannot use index 0 for module BTF fd */ + if (!obj->fd_array_cnt) + obj->fd_array_cnt = 1; + + ret = libbpf_ensure_mem((void **)&obj->fd_array, &obj->fd_array_cap, sizeof(int), + obj->fd_array_cnt + 1); + if (ret) + return ret; + mod_btf->fd_array_idx = obj->fd_array_cnt; + /* we assume module BTF FD is always >0 */ + obj->fd_array[obj->fd_array_cnt++] = mod_btf->fd; } -out: - fclose(f); - return err; + ext->is_set = true; + ext->ksym.kernel_btf_id = kfunc_id; + ext->ksym.btf_fd_idx = mod_btf ? mod_btf->fd_array_idx : 0; + /* Also set kernel_btf_obj_fd to make sure that bpf_object__relocate_data() + * populates FD into ld_imm64 insn when it's used to point to kfunc. + * {kernel_btf_id, btf_fd_idx} -> fixup bpf_call. + * {kernel_btf_id, kernel_btf_obj_fd} -> fixup ld_imm64. + */ + ext->ksym.kernel_btf_obj_fd = mod_btf ? mod_btf->fd : 0; + pr_debug("extern (func ksym) '%s': resolved to %s [%d]\n", + ext->name, mod_btf ? mod_btf->name : "vmlinux", kfunc_id); + + return 0; } static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj) { + const struct btf_type *t; struct extern_desc *ext; - int i, id; + int i, err; for (i = 0; i < obj->nr_extern; i++) { - const struct btf_type *targ_var, *targ_type; - __u32 targ_type_id, local_type_id; - const char *targ_var_name; - int ret; - ext = &obj->externs[i]; if (ext->type != EXT_KSYM || !ext->ksym.type_id) continue; - id = btf__find_by_name_kind(obj->btf_vmlinux, ext->name, - BTF_KIND_VAR); - if (id <= 0) { - pr_warn("extern (ksym) '%s': failed to find BTF ID in vmlinux BTF.\n", - ext->name); - return -ESRCH; - } - - /* find local type_id */ - local_type_id = ext->ksym.type_id; - - /* find target type_id */ - targ_var = btf__type_by_id(obj->btf_vmlinux, id); - targ_var_name = btf__name_by_offset(obj->btf_vmlinux, - targ_var->name_off); - targ_type = skip_mods_and_typedefs(obj->btf_vmlinux, - targ_var->type, - &targ_type_id); - - ret = bpf_core_types_are_compat(obj->btf, local_type_id, - obj->btf_vmlinux, targ_type_id); - if (ret <= 0) { - const struct btf_type *local_type; - const char *targ_name, *local_name; - - local_type = btf__type_by_id(obj->btf, local_type_id); - local_name = btf__name_by_offset(obj->btf, - local_type->name_off); - targ_name = btf__name_by_offset(obj->btf_vmlinux, - targ_type->name_off); - - pr_warn("extern (ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n", - ext->name, local_type_id, - btf_kind_str(local_type), local_name, targ_type_id, - btf_kind_str(targ_type), targ_name); - return -EINVAL; + if (obj->gen_loader) { + ext->is_set = true; + ext->ksym.kernel_btf_obj_fd = 0; + ext->ksym.kernel_btf_id = 0; + continue; } - - ext->is_set = true; - ext->ksym.vmlinux_btf_id = id; - pr_debug("extern (ksym) '%s': resolved to [%d] %s %s\n", - ext->name, id, btf_kind_str(targ_var), targ_var_name); + t = btf__type_by_id(obj->btf, ext->btf_id); + if (btf_is_var(t)) + err = bpf_object__resolve_ksym_var_btf_id(obj, ext); + else + err = bpf_object__resolve_ksym_func_btf_id(obj, ext); + if (err) + return err; } return 0; } @@ -7173,29 +8241,52 @@ static int bpf_object__resolve_externs(struct bpf_object *obj, for (i = 0; i < obj->nr_extern; i++) { ext = &obj->externs[i]; - if (ext->type == EXT_KCFG && - strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) { - void *ext_val = kcfg_data + ext->kcfg.data_off; - __u32 kver = get_kernel_version(); + if (ext->type == EXT_KSYM) { + if (ext->ksym.type_id) + need_vmlinux_btf = true; + else + need_kallsyms = true; + continue; + } else if (ext->type == EXT_KCFG) { + void *ext_ptr = kcfg_data + ext->kcfg.data_off; + __u64 value = 0; - if (!kver) { - pr_warn("failed to get kernel version\n"); + /* Kconfig externs need actual /proc/config.gz */ + if (str_has_pfx(ext->name, "CONFIG_")) { + need_config = true; + continue; + } + + /* Virtual kcfg externs are customly handled by libbpf */ + if (strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) { + value = get_kernel_version(); + if (!value) { + pr_warn("extern (kcfg) '%s': failed to get kernel version\n", ext->name); + return -EINVAL; + } + } else if (strcmp(ext->name, "LINUX_HAS_BPF_COOKIE") == 0) { + value = kernel_supports(obj, FEAT_BPF_COOKIE); + } else if (strcmp(ext->name, "LINUX_HAS_SYSCALL_WRAPPER") == 0) { + value = kernel_supports(obj, FEAT_SYSCALL_WRAPPER); + } else if (!str_has_pfx(ext->name, "LINUX_") || !ext->is_weak) { + /* Currently libbpf supports only CONFIG_ and LINUX_ prefixed + * __kconfig externs, where LINUX_ ones are virtual and filled out + * customly by libbpf (their values don't come from Kconfig). + * If LINUX_xxx variable is not recognized by libbpf, but is marked + * __weak, it defaults to zero value, just like for CONFIG_xxx + * externs. + */ + pr_warn("extern (kcfg) '%s': unrecognized virtual extern\n", ext->name); return -EINVAL; } - err = set_kcfg_value_num(ext, ext_val, kver); + + err = set_kcfg_value_num(ext, ext_ptr, value); if (err) return err; - pr_debug("extern (kcfg) %s=0x%x\n", ext->name, kver); - } else if (ext->type == EXT_KCFG && - strncmp(ext->name, "CONFIG_", 7) == 0) { - need_config = true; - } else if (ext->type == EXT_KSYM) { - if (ext->ksym.type_id) - need_vmlinux_btf = true; - else - need_kallsyms = true; + pr_debug("extern (kcfg) '%s': set to 0x%llx\n", + ext->name, (long long)value); } else { - pr_warn("unrecognized extern '%s'\n", ext->name); + pr_warn("extern '%s': unrecognized extern kind\n", ext->name); return -EINVAL; } } @@ -7231,10 +8322,10 @@ static int bpf_object__resolve_externs(struct bpf_object *obj, ext = &obj->externs[i]; if (!ext->is_set && !ext->is_weak) { - pr_warn("extern %s (strong) not resolved\n", ext->name); + pr_warn("extern '%s' (strong): not resolved\n", ext->name); return -ESRCH; } else if (!ext->is_set) { - pr_debug("extern %s (weak) not resolved, defaulting to zero\n", + pr_debug("extern '%s' (weak): not resolved, defaulting to zero\n", ext->name); } } @@ -7242,32 +8333,95 @@ static int bpf_object__resolve_externs(struct bpf_object *obj, return 0; } -int bpf_object__load_xattr(struct bpf_object_load_attr *attr) +static void bpf_map_prepare_vdata(const struct bpf_map *map) +{ + struct bpf_struct_ops *st_ops; + __u32 i; + + st_ops = map->st_ops; + for (i = 0; i < btf_vlen(st_ops->type); i++) { + struct bpf_program *prog = st_ops->progs[i]; + void *kern_data; + int prog_fd; + + if (!prog) + continue; + + prog_fd = bpf_program__fd(prog); + kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i]; + *(unsigned long *)kern_data = prog_fd; + } +} + +static int bpf_object_prepare_struct_ops(struct bpf_object *obj) +{ + struct bpf_map *map; + int i; + + for (i = 0; i < obj->nr_maps; i++) { + map = &obj->maps[i]; + + if (!bpf_map__is_struct_ops(map)) + continue; + + if (!map->autocreate) + continue; + + bpf_map_prepare_vdata(map); + } + + return 0; +} + +static int bpf_object_load(struct bpf_object *obj, int extra_log_level, const char *target_btf_path) { - struct bpf_object *obj; int err, i; - if (!attr) - return -EINVAL; - obj = attr->obj; if (!obj) - return -EINVAL; + return libbpf_err(-EINVAL); if (obj->loaded) { pr_warn("object '%s': load can't be attempted twice\n", obj->name); - return -EINVAL; + return libbpf_err(-EINVAL); } - err = bpf_object__probe_loading(obj); - err = err ? : bpf_object__load_vmlinux_btf(obj); + if (obj->gen_loader) + bpf_gen__init(obj->gen_loader, extra_log_level, obj->nr_programs, obj->nr_maps); + + err = bpf_object_prepare_token(obj); + err = err ? : bpf_object__probe_loading(obj); + err = err ? : bpf_object__load_vmlinux_btf(obj, false); err = err ? : bpf_object__resolve_externs(obj, obj->kconfig); - err = err ? : bpf_object__sanitize_and_load_btf(obj); err = err ? : bpf_object__sanitize_maps(obj); err = err ? : bpf_object__init_kern_struct_ops_maps(obj); + err = err ? : bpf_object_adjust_struct_ops_autoload(obj); + err = err ? : bpf_object__relocate(obj, obj->btf_custom_path ? : target_btf_path); + err = err ? : bpf_object__sanitize_and_load_btf(obj); err = err ? : bpf_object__create_maps(obj); - err = err ? : bpf_object__relocate(obj, attr->target_btf_path); - err = err ? : bpf_object__load_progs(obj, attr->log_level); + err = err ? : bpf_object__load_progs(obj, extra_log_level); + err = err ? : bpf_object_init_prog_arrays(obj); + err = err ? : bpf_object_prepare_struct_ops(obj); + + if (obj->gen_loader) { + /* reset FDs */ + if (obj->btf) + btf__set_fd(obj->btf, -1); + if (!err) + err = bpf_gen__finish(obj->gen_loader, obj->nr_programs, obj->nr_maps); + } + /* clean up fd_array */ + zfree(&obj->fd_array); + + /* clean up module BTFs */ + for (i = 0; i < obj->btf_module_cnt; i++) { + close(obj->btf_modules[i].fd); + btf__free(obj->btf_modules[i].btf); + free(obj->btf_modules[i].name); + } + free(obj->btf_modules); + + /* clean up vmlinux BTF */ btf__free(obj->btf_vmlinux); obj->btf_vmlinux = NULL; @@ -7283,18 +8437,14 @@ out: if (obj->maps[i].pinned && !obj->maps[i].reused) bpf_map__unpin(&obj->maps[i], NULL); - bpf_object__unload(obj); + bpf_object_unload(obj); pr_warn("failed to load object '%s'\n", obj->path); - return err; + return libbpf_err(err); } int bpf_object__load(struct bpf_object *obj) { - struct bpf_object_load_attr attr = { - .obj = obj, - }; - - return bpf_object__load_xattr(&attr); + return bpf_object_load(obj, 0, NULL); } static int make_parent_dir(const char *path) @@ -7349,178 +8499,53 @@ static int check_path(const char *path) return err; } -int bpf_program__pin_instance(struct bpf_program *prog, const char *path, - int instance) +int bpf_program__pin(struct bpf_program *prog, const char *path) { char *cp, errmsg[STRERR_BUFSIZE]; int err; + if (prog->fd < 0) { + pr_warn("prog '%s': can't pin program that wasn't loaded\n", prog->name); + return libbpf_err(-EINVAL); + } + err = make_parent_dir(path); if (err) - return err; + return libbpf_err(err); err = check_path(path); if (err) - return err; + return libbpf_err(err); - if (prog == NULL) { - pr_warn("invalid program pointer\n"); - return -EINVAL; - } - - if (instance < 0 || instance >= prog->instances.nr) { - pr_warn("invalid prog instance %d of prog %s (max %d)\n", - instance, prog->name, prog->instances.nr); - return -EINVAL; - } - - if (bpf_obj_pin(prog->instances.fds[instance], path)) { + if (bpf_obj_pin(prog->fd, path)) { err = -errno; cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); - pr_warn("failed to pin program: %s\n", cp); - return err; + pr_warn("prog '%s': failed to pin at '%s': %s\n", prog->name, path, cp); + return libbpf_err(err); } - pr_debug("pinned program '%s'\n", path); + pr_debug("prog '%s': pinned at '%s'\n", prog->name, path); return 0; } -int bpf_program__unpin_instance(struct bpf_program *prog, const char *path, - int instance) +int bpf_program__unpin(struct bpf_program *prog, const char *path) { int err; - err = check_path(path); - if (err) - return err; - - if (prog == NULL) { - pr_warn("invalid program pointer\n"); - return -EINVAL; - } - - if (instance < 0 || instance >= prog->instances.nr) { - pr_warn("invalid prog instance %d of prog %s (max %d)\n", - instance, prog->name, prog->instances.nr); - return -EINVAL; + if (prog->fd < 0) { + pr_warn("prog '%s': can't unpin program that wasn't loaded\n", prog->name); + return libbpf_err(-EINVAL); } - err = unlink(path); - if (err != 0) - return -errno; - pr_debug("unpinned program '%s'\n", path); - - return 0; -} - -int bpf_program__pin(struct bpf_program *prog, const char *path) -{ - int i, err; - - err = make_parent_dir(path); - if (err) - return err; - err = check_path(path); if (err) - return err; - - if (prog == NULL) { - pr_warn("invalid program pointer\n"); - return -EINVAL; - } - - if (prog->instances.nr <= 0) { - pr_warn("no instances of prog %s to pin\n", prog->name); - return -EINVAL; - } - - if (prog->instances.nr == 1) { - /* don't create subdirs when pinning single instance */ - return bpf_program__pin_instance(prog, path, 0); - } - - for (i = 0; i < prog->instances.nr; i++) { - char buf[PATH_MAX]; - int len; - - len = snprintf(buf, PATH_MAX, "%s/%d", path, i); - if (len < 0) { - err = -EINVAL; - goto err_unpin; - } else if (len >= PATH_MAX) { - err = -ENAMETOOLONG; - goto err_unpin; - } - - err = bpf_program__pin_instance(prog, buf, i); - if (err) - goto err_unpin; - } - - return 0; - -err_unpin: - for (i = i - 1; i >= 0; i--) { - char buf[PATH_MAX]; - int len; - - len = snprintf(buf, PATH_MAX, "%s/%d", path, i); - if (len < 0) - continue; - else if (len >= PATH_MAX) - continue; - - bpf_program__unpin_instance(prog, buf, i); - } - - rmdir(path); - - return err; -} + return libbpf_err(err); -int bpf_program__unpin(struct bpf_program *prog, const char *path) -{ - int i, err; - - err = check_path(path); - if (err) - return err; - - if (prog == NULL) { - pr_warn("invalid program pointer\n"); - return -EINVAL; - } - - if (prog->instances.nr <= 0) { - pr_warn("no instances of prog %s to pin\n", prog->name); - return -EINVAL; - } - - if (prog->instances.nr == 1) { - /* don't create subdirs when pinning single instance */ - return bpf_program__unpin_instance(prog, path, 0); - } - - for (i = 0; i < prog->instances.nr; i++) { - char buf[PATH_MAX]; - int len; - - len = snprintf(buf, PATH_MAX, "%s/%d", path, i); - if (len < 0) - return -EINVAL; - else if (len >= PATH_MAX) - return -ENAMETOOLONG; - - err = bpf_program__unpin_instance(prog, buf, i); - if (err) - return err; - } - - err = rmdir(path); + err = unlink(path); if (err) - return -errno; + return libbpf_err(-errno); + pr_debug("prog '%s': unpinned from '%s'\n", prog->name, path); return 0; } @@ -7531,14 +8556,14 @@ int bpf_map__pin(struct bpf_map *map, const char *path) if (map == NULL) { pr_warn("invalid map pointer\n"); - return -EINVAL; + return libbpf_err(-EINVAL); } if (map->pin_path) { if (path && strcmp(path, map->pin_path)) { pr_warn("map '%s' already has pin path '%s' different from '%s'\n", bpf_map__name(map), map->pin_path, path); - return -EINVAL; + return libbpf_err(-EINVAL); } else if (map->pinned) { pr_debug("map '%s' already pinned at '%s'; not re-pinning\n", bpf_map__name(map), map->pin_path); @@ -7548,10 +8573,10 @@ int bpf_map__pin(struct bpf_map *map, const char *path) if (!path) { pr_warn("missing a path to pin map '%s' at\n", bpf_map__name(map)); - return -EINVAL; + return libbpf_err(-EINVAL); } else if (map->pinned) { pr_warn("map '%s' already pinned\n", bpf_map__name(map)); - return -EEXIST; + return libbpf_err(-EEXIST); } map->pin_path = strdup(path); @@ -7563,11 +8588,11 @@ int bpf_map__pin(struct bpf_map *map, const char *path) err = make_parent_dir(map->pin_path); if (err) - return err; + return libbpf_err(err); err = check_path(map->pin_path); if (err) - return err; + return libbpf_err(err); if (bpf_obj_pin(map->fd, map->pin_path)) { err = -errno; @@ -7582,7 +8607,7 @@ int bpf_map__pin(struct bpf_map *map, const char *path) out_err: cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); pr_warn("failed to pin map: %s\n", cp); - return err; + return libbpf_err(err); } int bpf_map__unpin(struct bpf_map *map, const char *path) @@ -7591,29 +8616,29 @@ int bpf_map__unpin(struct bpf_map *map, const char *path) if (map == NULL) { pr_warn("invalid map pointer\n"); - return -EINVAL; + return libbpf_err(-EINVAL); } if (map->pin_path) { if (path && strcmp(path, map->pin_path)) { pr_warn("map '%s' already has pin path '%s' different from '%s'\n", bpf_map__name(map), map->pin_path, path); - return -EINVAL; + return libbpf_err(-EINVAL); } path = map->pin_path; } else if (!path) { pr_warn("no path to unpin map '%s' from\n", bpf_map__name(map)); - return -EINVAL; + return libbpf_err(-EINVAL); } err = check_path(path); if (err) - return err; + return libbpf_err(err); err = unlink(path); if (err != 0) - return -errno; + return libbpf_err(-errno); map->pinned = false; pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path); @@ -7628,7 +8653,7 @@ int bpf_map__set_pin_path(struct bpf_map *map, const char *path) if (path) { new = strdup(path); if (!new) - return -errno; + return libbpf_err(-errno); } free(map->pin_path); @@ -7636,7 +8661,10 @@ int bpf_map__set_pin_path(struct bpf_map *map, const char *path) return 0; } -const char *bpf_map__get_pin_path(const struct bpf_map *map) +__alias(bpf_map__pin_path) +const char *bpf_map__get_pin_path(const struct bpf_map *map); + +const char *bpf_map__pin_path(const struct bpf_map *map) { return map->pin_path; } @@ -7646,35 +8674,41 @@ bool bpf_map__is_pinned(const struct bpf_map *map) return map->pinned; } +static void sanitize_pin_path(char *s) +{ + /* bpffs disallows periods in path names */ + while (*s) { + if (*s == '.') + *s = '_'; + s++; + } +} + int bpf_object__pin_maps(struct bpf_object *obj, const char *path) { struct bpf_map *map; int err; if (!obj) - return -ENOENT; + return libbpf_err(-ENOENT); if (!obj->loaded) { pr_warn("object not yet loaded; load it first\n"); - return -ENOENT; + return libbpf_err(-ENOENT); } bpf_object__for_each_map(map, obj) { char *pin_path = NULL; char buf[PATH_MAX]; - if (path) { - int len; + if (!map->autocreate) + continue; - len = snprintf(buf, PATH_MAX, "%s/%s", path, - bpf_map__name(map)); - if (len < 0) { - err = -EINVAL; - goto err_unpin_maps; - } else if (len >= PATH_MAX) { - err = -ENAMETOOLONG; + if (path) { + err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); + if (err) goto err_unpin_maps; - } + sanitize_pin_path(buf); pin_path = buf; } else if (!map->pin_path) { continue; @@ -7688,14 +8722,14 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path) return 0; err_unpin_maps: - while ((map = bpf_map__prev(map, obj))) { + while ((map = bpf_object__prev_map(obj, map))) { if (!map->pin_path) continue; bpf_map__unpin(map, NULL); } - return err; + return libbpf_err(err); } int bpf_object__unpin_maps(struct bpf_object *obj, const char *path) @@ -7704,21 +8738,17 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path) int err; if (!obj) - return -ENOENT; + return libbpf_err(-ENOENT); bpf_object__for_each_map(map, obj) { char *pin_path = NULL; char buf[PATH_MAX]; if (path) { - int len; - - len = snprintf(buf, PATH_MAX, "%s/%s", path, - bpf_map__name(map)); - if (len < 0) - return -EINVAL; - else if (len >= PATH_MAX) - return -ENAMETOOLONG; + err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); + if (err) + return libbpf_err(err); + sanitize_pin_path(buf); pin_path = buf; } else if (!map->pin_path) { continue; @@ -7726,7 +8756,7 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path) err = bpf_map__unpin(map, pin_path); if (err) - return err; + return libbpf_err(err); } return 0; @@ -7735,29 +8765,21 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path) int bpf_object__pin_programs(struct bpf_object *obj, const char *path) { struct bpf_program *prog; + char buf[PATH_MAX]; int err; if (!obj) - return -ENOENT; + return libbpf_err(-ENOENT); if (!obj->loaded) { pr_warn("object not yet loaded; load it first\n"); - return -ENOENT; + return libbpf_err(-ENOENT); } bpf_object__for_each_program(prog, obj) { - char buf[PATH_MAX]; - int len; - - len = snprintf(buf, PATH_MAX, "%s/%s", path, - prog->pin_name); - if (len < 0) { - err = -EINVAL; - goto err_unpin_programs; - } else if (len >= PATH_MAX) { - err = -ENAMETOOLONG; + err = pathname_concat(buf, sizeof(buf), path, prog->name); + if (err) goto err_unpin_programs; - } err = bpf_program__pin(prog, buf); if (err) @@ -7767,21 +8789,14 @@ int bpf_object__pin_programs(struct bpf_object *obj, const char *path) return 0; err_unpin_programs: - while ((prog = bpf_program__prev(prog, obj))) { - char buf[PATH_MAX]; - int len; - - len = snprintf(buf, PATH_MAX, "%s/%s", path, - prog->pin_name); - if (len < 0) - continue; - else if (len >= PATH_MAX) + while ((prog = bpf_object__prev_program(obj, prog))) { + if (pathname_concat(buf, sizeof(buf), path, prog->name)) continue; bpf_program__unpin(prog, buf); } - return err; + return libbpf_err(err); } int bpf_object__unpin_programs(struct bpf_object *obj, const char *path) @@ -7790,22 +8805,18 @@ int bpf_object__unpin_programs(struct bpf_object *obj, const char *path) int err; if (!obj) - return -ENOENT; + return libbpf_err(-ENOENT); bpf_object__for_each_program(prog, obj) { char buf[PATH_MAX]; - int len; - len = snprintf(buf, PATH_MAX, "%s/%s", path, - prog->pin_name); - if (len < 0) - return -EINVAL; - else if (len >= PATH_MAX) - return -ENAMETOOLONG; + err = pathname_concat(buf, sizeof(buf), path, prog->name); + if (err) + return libbpf_err(err); err = bpf_program__unpin(prog, buf); if (err) - return err; + return libbpf_err(err); } return 0; @@ -7817,24 +8828,34 @@ int bpf_object__pin(struct bpf_object *obj, const char *path) err = bpf_object__pin_maps(obj, path); if (err) - return err; + return libbpf_err(err); err = bpf_object__pin_programs(obj, path); if (err) { bpf_object__unpin_maps(obj, path); - return err; + return libbpf_err(err); } return 0; } -static void bpf_map__destroy(struct bpf_map *map) +int bpf_object__unpin(struct bpf_object *obj, const char *path) { - if (map->clear_priv) - map->clear_priv(map, map->priv); - map->priv = NULL; - map->clear_priv = NULL; + int err; + + err = bpf_object__unpin_programs(obj, path); + if (err) + return libbpf_err(err); + + err = bpf_object__unpin_maps(obj, path); + if (err) + return libbpf_err(err); + + return 0; +} +static void bpf_map__destroy(struct bpf_map *map) +{ if (map->inner_map) { bpf_map__destroy(map->inner_map); zfree(&map->inner_map); @@ -7843,10 +8864,9 @@ static void bpf_map__destroy(struct bpf_map *map) zfree(&map->init_slots); map->init_slots_sz = 0; - if (map->mmaped) { + if (map->mmaped && map->mmaped != map->obj->arena_data) munmap(map->mmaped, bpf_map_mmap_sz(map)); - map->mmaped = NULL; - } + map->mmaped = NULL; if (map->st_ops) { zfree(&map->st_ops->data); @@ -7856,6 +8876,7 @@ static void bpf_map__destroy(struct bpf_map *map) } zfree(&map->name); + zfree(&map->real_name); zfree(&map->pin_path); if (map->fd >= 0) @@ -7869,18 +8890,25 @@ void bpf_object__close(struct bpf_object *obj) if (IS_ERR_OR_NULL(obj)) return; - if (obj->clear_priv) - obj->clear_priv(obj, obj->priv); + usdt_manager_free(obj->usdt_man); + obj->usdt_man = NULL; + bpf_gen__free(obj->gen_loader); bpf_object__elf_finish(obj); - bpf_object__unload(obj); + bpf_object_unload(obj); btf__free(obj->btf); + btf__free(obj->btf_vmlinux); btf_ext__free(obj->btf_ext); for (i = 0; i < obj->nr_maps; i++) bpf_map__destroy(&obj->maps[i]); + zfree(&obj->btf_custom_path); zfree(&obj->kconfig); + + for (i = 0; i < obj->nr_extern; i++) + zfree(&obj->externs[i].essent_name); + zfree(&obj->externs); obj->nr_extern = 0; @@ -7893,32 +8921,19 @@ void bpf_object__close(struct bpf_object *obj) } zfree(&obj->programs); - list_del(&obj->list); - free(obj); -} - -struct bpf_object * -bpf_object__next(struct bpf_object *prev) -{ - struct bpf_object *next; - - if (!prev) - next = list_first_entry(&bpf_objects_list, - struct bpf_object, - list); - else - next = list_next_entry(prev, list); + zfree(&obj->feat_cache); + zfree(&obj->token_path); + if (obj->token_fd > 0) + close(obj->token_fd); - /* Empty list is noticed here so don't need checking on entry. */ - if (&next->list == &bpf_objects_list) - return NULL; + zfree(&obj->arena_data); - return next; + free(obj); } const char *bpf_object__name(const struct bpf_object *obj) { - return obj ? obj->name : ERR_PTR(-EINVAL); + return obj ? obj->name : libbpf_err_ptr(-EINVAL); } unsigned int bpf_object__kversion(const struct bpf_object *obj) @@ -7936,20 +8951,30 @@ int bpf_object__btf_fd(const struct bpf_object *obj) return obj->btf ? btf__fd(obj->btf) : -1; } -int bpf_object__set_priv(struct bpf_object *obj, void *priv, - bpf_object_clear_priv_t clear_priv) +int bpf_object__set_kversion(struct bpf_object *obj, __u32 kern_version) { - if (obj->priv && obj->clear_priv) - obj->clear_priv(obj, obj->priv); + if (obj->loaded) + return libbpf_err(-EINVAL); + + obj->kern_version = kern_version; - obj->priv = priv; - obj->clear_priv = clear_priv; return 0; } -void *bpf_object__priv(const struct bpf_object *obj) +int bpf_object__gen_loader(struct bpf_object *obj, struct gen_loader_opts *opts) { - return obj ? obj->priv : ERR_PTR(-EINVAL); + struct bpf_gen *gen; + + if (!opts) + return -EFAULT; + if (!OPTS_VALID(opts, gen_loader_opts)) + return -EINVAL; + gen = calloc(sizeof(*gen), 1); + if (!gen) + return -ENOMEM; + gen->opts = opts; + obj->gen_loader = gen; + return 0; } static struct bpf_program * @@ -7969,7 +8994,7 @@ __bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj, if (p->obj != obj) { pr_warn("error: program handler doesn't match object\n"); - return NULL; + return errno = EINVAL, NULL; } idx = (p - obj->programs) + (forward ? 1 : -1); @@ -7979,7 +9004,7 @@ __bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj, } struct bpf_program * -bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj) +bpf_object__next_program(const struct bpf_object *obj, struct bpf_program *prev) { struct bpf_program *prog = prev; @@ -7991,7 +9016,7 @@ bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj) } struct bpf_program * -bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj) +bpf_object__prev_program(const struct bpf_object *obj, struct bpf_program *next) { struct bpf_program *prog = next; @@ -8002,22 +9027,6 @@ bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj) return prog; } -int bpf_program__set_priv(struct bpf_program *prog, void *priv, - bpf_program_clear_priv_t clear_priv) -{ - if (prog->priv && prog->clear_priv) - prog->clear_priv(prog, prog->priv); - - prog->priv = priv; - prog->clear_priv = clear_priv; - return 0; -} - -void *bpf_program__priv(const struct bpf_program *prog) -{ - return prog ? prog->priv : ERR_PTR(-EINVAL); -} - void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex) { prog->prog_ifindex = ifindex; @@ -8033,369 +9042,441 @@ const char *bpf_program__section_name(const struct bpf_program *prog) return prog->sec_name; } -const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy) -{ - const char *title; - - title = prog->sec_name; - if (needs_copy) { - title = strdup(title); - if (!title) { - pr_warn("failed to strdup program title\n"); - return ERR_PTR(-ENOMEM); - } - } - - return title; -} - bool bpf_program__autoload(const struct bpf_program *prog) { - return prog->load; + return prog->autoload; } int bpf_program__set_autoload(struct bpf_program *prog, bool autoload) { if (prog->obj->loaded) - return -EINVAL; + return libbpf_err(-EINVAL); - prog->load = autoload; + prog->autoload = autoload; return 0; } -int bpf_program__fd(const struct bpf_program *prog) +bool bpf_program__autoattach(const struct bpf_program *prog) { - return bpf_program__nth_fd(prog, 0); + return prog->autoattach; } -size_t bpf_program__size(const struct bpf_program *prog) +void bpf_program__set_autoattach(struct bpf_program *prog, bool autoattach) { - return prog->insns_cnt * BPF_INSN_SZ; + prog->autoattach = autoattach; } -int bpf_program__set_prep(struct bpf_program *prog, int nr_instances, - bpf_program_prep_t prep) +const struct bpf_insn *bpf_program__insns(const struct bpf_program *prog) { - int *instances_fds; + return prog->insns; +} - if (nr_instances <= 0 || !prep) - return -EINVAL; +size_t bpf_program__insn_cnt(const struct bpf_program *prog) +{ + return prog->insns_cnt; +} - if (prog->instances.nr > 0 || prog->instances.fds) { - pr_warn("Can't set pre-processor after loading\n"); - return -EINVAL; - } +int bpf_program__set_insns(struct bpf_program *prog, + struct bpf_insn *new_insns, size_t new_insn_cnt) +{ + struct bpf_insn *insns; + + if (prog->obj->loaded) + return -EBUSY; - instances_fds = malloc(sizeof(int) * nr_instances); - if (!instances_fds) { - pr_warn("alloc memory failed for fds\n"); + insns = libbpf_reallocarray(prog->insns, new_insn_cnt, sizeof(*insns)); + /* NULL is a valid return from reallocarray if the new count is zero */ + if (!insns && new_insn_cnt) { + pr_warn("prog '%s': failed to realloc prog code\n", prog->name); return -ENOMEM; } + memcpy(insns, new_insns, new_insn_cnt * sizeof(*insns)); - /* fill all fd with -1 */ - memset(instances_fds, -1, sizeof(int) * nr_instances); - - prog->instances.nr = nr_instances; - prog->instances.fds = instances_fds; - prog->preprocessor = prep; + prog->insns = insns; + prog->insns_cnt = new_insn_cnt; return 0; } -int bpf_program__nth_fd(const struct bpf_program *prog, int n) +int bpf_program__fd(const struct bpf_program *prog) { - int fd; - if (!prog) - return -EINVAL; - - if (n >= prog->instances.nr || n < 0) { - pr_warn("Can't get the %dth fd from program %s: only %d instances\n", - n, prog->name, prog->instances.nr); - return -EINVAL; - } + return libbpf_err(-EINVAL); - fd = prog->instances.fds[n]; - if (fd < 0) { - pr_warn("%dth instance of program '%s' is invalid\n", - n, prog->name); - return -ENOENT; - } + if (prog->fd < 0) + return libbpf_err(-ENOENT); - return fd; + return prog->fd; } -enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog) +__alias(bpf_program__type) +enum bpf_prog_type bpf_program__get_type(const struct bpf_program *prog); + +enum bpf_prog_type bpf_program__type(const struct bpf_program *prog) { return prog->type; } -void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type) +static size_t custom_sec_def_cnt; +static struct bpf_sec_def *custom_sec_defs; +static struct bpf_sec_def custom_fallback_def; +static bool has_custom_fallback_def; +static int last_custom_sec_def_handler_id; + +int bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type) { + if (prog->obj->loaded) + return libbpf_err(-EBUSY); + + /* if type is not changed, do nothing */ + if (prog->type == type) + return 0; + prog->type = type; + + /* If a program type was changed, we need to reset associated SEC() + * handler, as it will be invalid now. The only exception is a generic + * fallback handler, which by definition is program type-agnostic and + * is a catch-all custom handler, optionally set by the application, + * so should be able to handle any type of BPF program. + */ + if (prog->sec_def != &custom_fallback_def) + prog->sec_def = NULL; + return 0; } -static bool bpf_program__is_type(const struct bpf_program *prog, - enum bpf_prog_type type) -{ - return prog ? (prog->type == type) : false; -} - -#define BPF_PROG_TYPE_FNS(NAME, TYPE) \ -int bpf_program__set_##NAME(struct bpf_program *prog) \ -{ \ - if (!prog) \ - return -EINVAL; \ - bpf_program__set_type(prog, TYPE); \ - return 0; \ -} \ - \ -bool bpf_program__is_##NAME(const struct bpf_program *prog) \ -{ \ - return bpf_program__is_type(prog, TYPE); \ -} \ - -BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER); -BPF_PROG_TYPE_FNS(lsm, BPF_PROG_TYPE_LSM); -BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE); -BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS); -BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT); -BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT); -BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT); -BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP); -BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT); -BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING); -BPF_PROG_TYPE_FNS(struct_ops, BPF_PROG_TYPE_STRUCT_OPS); -BPF_PROG_TYPE_FNS(extension, BPF_PROG_TYPE_EXT); -BPF_PROG_TYPE_FNS(sk_lookup, BPF_PROG_TYPE_SK_LOOKUP); - -enum bpf_attach_type -bpf_program__get_expected_attach_type(struct bpf_program *prog) +__alias(bpf_program__expected_attach_type) +enum bpf_attach_type bpf_program__get_expected_attach_type(const struct bpf_program *prog); + +enum bpf_attach_type bpf_program__expected_attach_type(const struct bpf_program *prog) { return prog->expected_attach_type; } -void bpf_program__set_expected_attach_type(struct bpf_program *prog, +int bpf_program__set_expected_attach_type(struct bpf_program *prog, enum bpf_attach_type type) { + if (prog->obj->loaded) + return libbpf_err(-EBUSY); + prog->expected_attach_type = type; + return 0; } -#define BPF_PROG_SEC_IMPL(string, ptype, eatype, eatype_optional, \ - attachable, attach_btf) \ - { \ - .sec = string, \ - .len = sizeof(string) - 1, \ - .prog_type = ptype, \ - .expected_attach_type = eatype, \ - .is_exp_attach_type_optional = eatype_optional, \ - .is_attachable = attachable, \ - .is_attach_btf = attach_btf, \ - } +__u32 bpf_program__flags(const struct bpf_program *prog) +{ + return prog->prog_flags; +} -/* Programs that can NOT be attached. */ -#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0, 0) +int bpf_program__set_flags(struct bpf_program *prog, __u32 flags) +{ + if (prog->obj->loaded) + return libbpf_err(-EBUSY); -/* Programs that can be attached. */ -#define BPF_APROG_SEC(string, ptype, atype) \ - BPF_PROG_SEC_IMPL(string, ptype, atype, true, 1, 0) + prog->prog_flags = flags; + return 0; +} -/* Programs that must specify expected attach type at load time. */ -#define BPF_EAPROG_SEC(string, ptype, eatype) \ - BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 1, 0) +__u32 bpf_program__log_level(const struct bpf_program *prog) +{ + return prog->log_level; +} -/* Programs that use BTF to identify attach point */ -#define BPF_PROG_BTF(string, ptype, eatype) \ - BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 0, 1) +int bpf_program__set_log_level(struct bpf_program *prog, __u32 log_level) +{ + if (prog->obj->loaded) + return libbpf_err(-EBUSY); -/* Programs that can be attached but attach type can't be identified by section - * name. Kept for backward compatibility. - */ -#define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype) + prog->log_level = log_level; + return 0; +} -#define SEC_DEF(sec_pfx, ptype, ...) { \ - .sec = sec_pfx, \ - .len = sizeof(sec_pfx) - 1, \ +const char *bpf_program__log_buf(const struct bpf_program *prog, size_t *log_size) +{ + *log_size = prog->log_size; + return prog->log_buf; +} + +int bpf_program__set_log_buf(struct bpf_program *prog, char *log_buf, size_t log_size) +{ + if (log_size && !log_buf) + return -EINVAL; + if (prog->log_size > UINT_MAX) + return -EINVAL; + if (prog->obj->loaded) + return -EBUSY; + + prog->log_buf = log_buf; + prog->log_size = log_size; + return 0; +} + +#define SEC_DEF(sec_pfx, ptype, atype, flags, ...) { \ + .sec = (char *)sec_pfx, \ .prog_type = BPF_PROG_TYPE_##ptype, \ + .expected_attach_type = atype, \ + .cookie = (long)(flags), \ + .prog_prepare_load_fn = libbpf_prepare_prog_load, \ __VA_ARGS__ \ } -static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec, - struct bpf_program *prog); -static struct bpf_link *attach_tp(const struct bpf_sec_def *sec, - struct bpf_program *prog); -static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec, - struct bpf_program *prog); -static struct bpf_link *attach_trace(const struct bpf_sec_def *sec, - struct bpf_program *prog); -static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec, - struct bpf_program *prog); -static struct bpf_link *attach_iter(const struct bpf_sec_def *sec, - struct bpf_program *prog); +static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_ksyscall(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_usdt(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link); static const struct bpf_sec_def section_defs[] = { - BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER), - BPF_PROG_SEC("sk_reuseport", BPF_PROG_TYPE_SK_REUSEPORT), - SEC_DEF("kprobe/", KPROBE, - .attach_fn = attach_kprobe), - BPF_PROG_SEC("uprobe/", BPF_PROG_TYPE_KPROBE), - SEC_DEF("kretprobe/", KPROBE, - .attach_fn = attach_kprobe), - BPF_PROG_SEC("uretprobe/", BPF_PROG_TYPE_KPROBE), - BPF_PROG_SEC("classifier", BPF_PROG_TYPE_SCHED_CLS), - BPF_PROG_SEC("action", BPF_PROG_TYPE_SCHED_ACT), - SEC_DEF("tracepoint/", TRACEPOINT, - .attach_fn = attach_tp), - SEC_DEF("tp/", TRACEPOINT, - .attach_fn = attach_tp), - SEC_DEF("raw_tracepoint/", RAW_TRACEPOINT, - .attach_fn = attach_raw_tp), - SEC_DEF("raw_tp/", RAW_TRACEPOINT, - .attach_fn = attach_raw_tp), - SEC_DEF("tp_btf/", TRACING, - .expected_attach_type = BPF_TRACE_RAW_TP, - .is_attach_btf = true, - .attach_fn = attach_trace), - SEC_DEF("fentry/", TRACING, - .expected_attach_type = BPF_TRACE_FENTRY, - .is_attach_btf = true, - .attach_fn = attach_trace), - SEC_DEF("fmod_ret/", TRACING, - .expected_attach_type = BPF_MODIFY_RETURN, - .is_attach_btf = true, - .attach_fn = attach_trace), - SEC_DEF("fexit/", TRACING, - .expected_attach_type = BPF_TRACE_FEXIT, - .is_attach_btf = true, - .attach_fn = attach_trace), - SEC_DEF("fentry.s/", TRACING, - .expected_attach_type = BPF_TRACE_FENTRY, - .is_attach_btf = true, - .is_sleepable = true, - .attach_fn = attach_trace), - SEC_DEF("fmod_ret.s/", TRACING, - .expected_attach_type = BPF_MODIFY_RETURN, - .is_attach_btf = true, - .is_sleepable = true, - .attach_fn = attach_trace), - SEC_DEF("fexit.s/", TRACING, - .expected_attach_type = BPF_TRACE_FEXIT, - .is_attach_btf = true, - .is_sleepable = true, - .attach_fn = attach_trace), - SEC_DEF("freplace/", EXT, - .is_attach_btf = true, - .attach_fn = attach_trace), - SEC_DEF("lsm/", LSM, - .is_attach_btf = true, - .expected_attach_type = BPF_LSM_MAC, - .attach_fn = attach_lsm), - SEC_DEF("lsm.s/", LSM, - .is_attach_btf = true, - .is_sleepable = true, - .expected_attach_type = BPF_LSM_MAC, - .attach_fn = attach_lsm), - SEC_DEF("iter/", TRACING, - .expected_attach_type = BPF_TRACE_ITER, - .is_attach_btf = true, - .attach_fn = attach_iter), - BPF_EAPROG_SEC("xdp_devmap/", BPF_PROG_TYPE_XDP, - BPF_XDP_DEVMAP), - BPF_EAPROG_SEC("xdp_cpumap/", BPF_PROG_TYPE_XDP, - BPF_XDP_CPUMAP), - BPF_APROG_SEC("xdp", BPF_PROG_TYPE_XDP, - BPF_XDP), - BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT), - BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN), - BPF_PROG_SEC("lwt_out", BPF_PROG_TYPE_LWT_OUT), - BPF_PROG_SEC("lwt_xmit", BPF_PROG_TYPE_LWT_XMIT), - BPF_PROG_SEC("lwt_seg6local", BPF_PROG_TYPE_LWT_SEG6LOCAL), - BPF_APROG_SEC("cgroup_skb/ingress", BPF_PROG_TYPE_CGROUP_SKB, - BPF_CGROUP_INET_INGRESS), - BPF_APROG_SEC("cgroup_skb/egress", BPF_PROG_TYPE_CGROUP_SKB, - BPF_CGROUP_INET_EGRESS), - BPF_APROG_COMPAT("cgroup/skb", BPF_PROG_TYPE_CGROUP_SKB), - BPF_EAPROG_SEC("cgroup/sock_create", BPF_PROG_TYPE_CGROUP_SOCK, - BPF_CGROUP_INET_SOCK_CREATE), - BPF_EAPROG_SEC("cgroup/sock_release", BPF_PROG_TYPE_CGROUP_SOCK, - BPF_CGROUP_INET_SOCK_RELEASE), - BPF_APROG_SEC("cgroup/sock", BPF_PROG_TYPE_CGROUP_SOCK, - BPF_CGROUP_INET_SOCK_CREATE), - BPF_EAPROG_SEC("cgroup/post_bind4", BPF_PROG_TYPE_CGROUP_SOCK, - BPF_CGROUP_INET4_POST_BIND), - BPF_EAPROG_SEC("cgroup/post_bind6", BPF_PROG_TYPE_CGROUP_SOCK, - BPF_CGROUP_INET6_POST_BIND), - BPF_APROG_SEC("cgroup/dev", BPF_PROG_TYPE_CGROUP_DEVICE, - BPF_CGROUP_DEVICE), - BPF_APROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS, - BPF_CGROUP_SOCK_OPS), - BPF_APROG_SEC("sk_skb/stream_parser", BPF_PROG_TYPE_SK_SKB, - BPF_SK_SKB_STREAM_PARSER), - BPF_APROG_SEC("sk_skb/stream_verdict", BPF_PROG_TYPE_SK_SKB, - BPF_SK_SKB_STREAM_VERDICT), - BPF_APROG_COMPAT("sk_skb", BPF_PROG_TYPE_SK_SKB), - BPF_APROG_SEC("sk_msg", BPF_PROG_TYPE_SK_MSG, - BPF_SK_MSG_VERDICT), - BPF_APROG_SEC("lirc_mode2", BPF_PROG_TYPE_LIRC_MODE2, - BPF_LIRC_MODE2), - BPF_APROG_SEC("flow_dissector", BPF_PROG_TYPE_FLOW_DISSECTOR, - BPF_FLOW_DISSECTOR), - BPF_EAPROG_SEC("cgroup/bind4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_INET4_BIND), - BPF_EAPROG_SEC("cgroup/bind6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_INET6_BIND), - BPF_EAPROG_SEC("cgroup/connect4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_INET4_CONNECT), - BPF_EAPROG_SEC("cgroup/connect6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_INET6_CONNECT), - BPF_EAPROG_SEC("cgroup/sendmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_UDP4_SENDMSG), - BPF_EAPROG_SEC("cgroup/sendmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_UDP6_SENDMSG), - BPF_EAPROG_SEC("cgroup/recvmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_UDP4_RECVMSG), - BPF_EAPROG_SEC("cgroup/recvmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_UDP6_RECVMSG), - BPF_EAPROG_SEC("cgroup/getpeername4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_INET4_GETPEERNAME), - BPF_EAPROG_SEC("cgroup/getpeername6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_INET6_GETPEERNAME), - BPF_EAPROG_SEC("cgroup/getsockname4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_INET4_GETSOCKNAME), - BPF_EAPROG_SEC("cgroup/getsockname6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, - BPF_CGROUP_INET6_GETSOCKNAME), - BPF_EAPROG_SEC("cgroup/sysctl", BPF_PROG_TYPE_CGROUP_SYSCTL, - BPF_CGROUP_SYSCTL), - BPF_EAPROG_SEC("cgroup/getsockopt", BPF_PROG_TYPE_CGROUP_SOCKOPT, - BPF_CGROUP_GETSOCKOPT), - BPF_EAPROG_SEC("cgroup/setsockopt", BPF_PROG_TYPE_CGROUP_SOCKOPT, - BPF_CGROUP_SETSOCKOPT), - BPF_PROG_SEC("struct_ops", BPF_PROG_TYPE_STRUCT_OPS), - BPF_EAPROG_SEC("sk_lookup/", BPF_PROG_TYPE_SK_LOOKUP, - BPF_SK_LOOKUP), + SEC_DEF("socket", SOCKET_FILTER, 0, SEC_NONE), + SEC_DEF("sk_reuseport/migrate", SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT_OR_MIGRATE, SEC_ATTACHABLE), + SEC_DEF("sk_reuseport", SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT, SEC_ATTACHABLE), + SEC_DEF("kprobe+", KPROBE, 0, SEC_NONE, attach_kprobe), + SEC_DEF("uprobe+", KPROBE, 0, SEC_NONE, attach_uprobe), + SEC_DEF("uprobe.s+", KPROBE, 0, SEC_SLEEPABLE, attach_uprobe), + SEC_DEF("kretprobe+", KPROBE, 0, SEC_NONE, attach_kprobe), + SEC_DEF("uretprobe+", KPROBE, 0, SEC_NONE, attach_uprobe), + SEC_DEF("uretprobe.s+", KPROBE, 0, SEC_SLEEPABLE, attach_uprobe), + SEC_DEF("kprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi), + SEC_DEF("kretprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi), + SEC_DEF("uprobe.multi+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi), + SEC_DEF("uretprobe.multi+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi), + SEC_DEF("uprobe.multi.s+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi), + SEC_DEF("uretprobe.multi.s+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi), + SEC_DEF("ksyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall), + SEC_DEF("kretsyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall), + SEC_DEF("usdt+", KPROBE, 0, SEC_USDT, attach_usdt), + SEC_DEF("usdt.s+", KPROBE, 0, SEC_USDT | SEC_SLEEPABLE, attach_usdt), + SEC_DEF("tc/ingress", SCHED_CLS, BPF_TCX_INGRESS, SEC_NONE), /* alias for tcx */ + SEC_DEF("tc/egress", SCHED_CLS, BPF_TCX_EGRESS, SEC_NONE), /* alias for tcx */ + SEC_DEF("tcx/ingress", SCHED_CLS, BPF_TCX_INGRESS, SEC_NONE), + SEC_DEF("tcx/egress", SCHED_CLS, BPF_TCX_EGRESS, SEC_NONE), + SEC_DEF("tc", SCHED_CLS, 0, SEC_NONE), /* deprecated / legacy, use tcx */ + SEC_DEF("classifier", SCHED_CLS, 0, SEC_NONE), /* deprecated / legacy, use tcx */ + SEC_DEF("action", SCHED_ACT, 0, SEC_NONE), /* deprecated / legacy, use tcx */ + SEC_DEF("netkit/primary", SCHED_CLS, BPF_NETKIT_PRIMARY, SEC_NONE), + SEC_DEF("netkit/peer", SCHED_CLS, BPF_NETKIT_PEER, SEC_NONE), + SEC_DEF("tracepoint+", TRACEPOINT, 0, SEC_NONE, attach_tp), + SEC_DEF("tp+", TRACEPOINT, 0, SEC_NONE, attach_tp), + SEC_DEF("raw_tracepoint+", RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp), + SEC_DEF("raw_tp+", RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp), + SEC_DEF("raw_tracepoint.w+", RAW_TRACEPOINT_WRITABLE, 0, SEC_NONE, attach_raw_tp), + SEC_DEF("raw_tp.w+", RAW_TRACEPOINT_WRITABLE, 0, SEC_NONE, attach_raw_tp), + SEC_DEF("tp_btf+", TRACING, BPF_TRACE_RAW_TP, SEC_ATTACH_BTF, attach_trace), + SEC_DEF("fentry+", TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF, attach_trace), + SEC_DEF("fmod_ret+", TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF, attach_trace), + SEC_DEF("fexit+", TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF, attach_trace), + SEC_DEF("fentry.s+", TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), + SEC_DEF("fmod_ret.s+", TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), + SEC_DEF("fexit.s+", TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), + SEC_DEF("freplace+", EXT, 0, SEC_ATTACH_BTF, attach_trace), + SEC_DEF("lsm+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF, attach_lsm), + SEC_DEF("lsm.s+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_lsm), + SEC_DEF("lsm_cgroup+", LSM, BPF_LSM_CGROUP, SEC_ATTACH_BTF), + SEC_DEF("iter+", TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF, attach_iter), + SEC_DEF("iter.s+", TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_iter), + SEC_DEF("syscall", SYSCALL, 0, SEC_SLEEPABLE), + SEC_DEF("xdp.frags/devmap", XDP, BPF_XDP_DEVMAP, SEC_XDP_FRAGS), + SEC_DEF("xdp/devmap", XDP, BPF_XDP_DEVMAP, SEC_ATTACHABLE), + SEC_DEF("xdp.frags/cpumap", XDP, BPF_XDP_CPUMAP, SEC_XDP_FRAGS), + SEC_DEF("xdp/cpumap", XDP, BPF_XDP_CPUMAP, SEC_ATTACHABLE), + SEC_DEF("xdp.frags", XDP, BPF_XDP, SEC_XDP_FRAGS), + SEC_DEF("xdp", XDP, BPF_XDP, SEC_ATTACHABLE_OPT), + SEC_DEF("perf_event", PERF_EVENT, 0, SEC_NONE), + SEC_DEF("lwt_in", LWT_IN, 0, SEC_NONE), + SEC_DEF("lwt_out", LWT_OUT, 0, SEC_NONE), + SEC_DEF("lwt_xmit", LWT_XMIT, 0, SEC_NONE), + SEC_DEF("lwt_seg6local", LWT_SEG6LOCAL, 0, SEC_NONE), + SEC_DEF("sockops", SOCK_OPS, BPF_CGROUP_SOCK_OPS, SEC_ATTACHABLE_OPT), + SEC_DEF("sk_skb/stream_parser", SK_SKB, BPF_SK_SKB_STREAM_PARSER, SEC_ATTACHABLE_OPT), + SEC_DEF("sk_skb/stream_verdict",SK_SKB, BPF_SK_SKB_STREAM_VERDICT, SEC_ATTACHABLE_OPT), + SEC_DEF("sk_skb", SK_SKB, 0, SEC_NONE), + SEC_DEF("sk_msg", SK_MSG, BPF_SK_MSG_VERDICT, SEC_ATTACHABLE_OPT), + SEC_DEF("lirc_mode2", LIRC_MODE2, BPF_LIRC_MODE2, SEC_ATTACHABLE_OPT), + SEC_DEF("flow_dissector", FLOW_DISSECTOR, BPF_FLOW_DISSECTOR, SEC_ATTACHABLE_OPT), + SEC_DEF("cgroup_skb/ingress", CGROUP_SKB, BPF_CGROUP_INET_INGRESS, SEC_ATTACHABLE_OPT), + SEC_DEF("cgroup_skb/egress", CGROUP_SKB, BPF_CGROUP_INET_EGRESS, SEC_ATTACHABLE_OPT), + SEC_DEF("cgroup/skb", CGROUP_SKB, 0, SEC_NONE), + SEC_DEF("cgroup/sock_create", CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE), + SEC_DEF("cgroup/sock_release", CGROUP_SOCK, BPF_CGROUP_INET_SOCK_RELEASE, SEC_ATTACHABLE), + SEC_DEF("cgroup/sock", CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE_OPT), + SEC_DEF("cgroup/post_bind4", CGROUP_SOCK, BPF_CGROUP_INET4_POST_BIND, SEC_ATTACHABLE), + SEC_DEF("cgroup/post_bind6", CGROUP_SOCK, BPF_CGROUP_INET6_POST_BIND, SEC_ATTACHABLE), + SEC_DEF("cgroup/bind4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_BIND, SEC_ATTACHABLE), + SEC_DEF("cgroup/bind6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_BIND, SEC_ATTACHABLE), + SEC_DEF("cgroup/connect4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_CONNECT, SEC_ATTACHABLE), + SEC_DEF("cgroup/connect6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_CONNECT, SEC_ATTACHABLE), + SEC_DEF("cgroup/connect_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_CONNECT, SEC_ATTACHABLE), + SEC_DEF("cgroup/sendmsg4", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_SENDMSG, SEC_ATTACHABLE), + SEC_DEF("cgroup/sendmsg6", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_SENDMSG, SEC_ATTACHABLE), + SEC_DEF("cgroup/sendmsg_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_SENDMSG, SEC_ATTACHABLE), + SEC_DEF("cgroup/recvmsg4", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_RECVMSG, SEC_ATTACHABLE), + SEC_DEF("cgroup/recvmsg6", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_RECVMSG, SEC_ATTACHABLE), + SEC_DEF("cgroup/recvmsg_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_RECVMSG, SEC_ATTACHABLE), + SEC_DEF("cgroup/getpeername4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETPEERNAME, SEC_ATTACHABLE), + SEC_DEF("cgroup/getpeername6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETPEERNAME, SEC_ATTACHABLE), + SEC_DEF("cgroup/getpeername_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_GETPEERNAME, SEC_ATTACHABLE), + SEC_DEF("cgroup/getsockname4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETSOCKNAME, SEC_ATTACHABLE), + SEC_DEF("cgroup/getsockname6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETSOCKNAME, SEC_ATTACHABLE), + SEC_DEF("cgroup/getsockname_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_GETSOCKNAME, SEC_ATTACHABLE), + SEC_DEF("cgroup/sysctl", CGROUP_SYSCTL, BPF_CGROUP_SYSCTL, SEC_ATTACHABLE), + SEC_DEF("cgroup/getsockopt", CGROUP_SOCKOPT, BPF_CGROUP_GETSOCKOPT, SEC_ATTACHABLE), + SEC_DEF("cgroup/setsockopt", CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE), + SEC_DEF("cgroup/dev", CGROUP_DEVICE, BPF_CGROUP_DEVICE, SEC_ATTACHABLE_OPT), + SEC_DEF("struct_ops+", STRUCT_OPS, 0, SEC_NONE), + SEC_DEF("struct_ops.s+", STRUCT_OPS, 0, SEC_SLEEPABLE), + SEC_DEF("sk_lookup", SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE), + SEC_DEF("netfilter", NETFILTER, BPF_NETFILTER, SEC_NONE), }; -#undef BPF_PROG_SEC_IMPL -#undef BPF_PROG_SEC -#undef BPF_APROG_SEC -#undef BPF_EAPROG_SEC -#undef BPF_APROG_COMPAT -#undef SEC_DEF +int libbpf_register_prog_handler(const char *sec, + enum bpf_prog_type prog_type, + enum bpf_attach_type exp_attach_type, + const struct libbpf_prog_handler_opts *opts) +{ + struct bpf_sec_def *sec_def; + + if (!OPTS_VALID(opts, libbpf_prog_handler_opts)) + return libbpf_err(-EINVAL); -#define MAX_TYPE_NAME_SIZE 32 + if (last_custom_sec_def_handler_id == INT_MAX) /* prevent overflow */ + return libbpf_err(-E2BIG); + + if (sec) { + sec_def = libbpf_reallocarray(custom_sec_defs, custom_sec_def_cnt + 1, + sizeof(*sec_def)); + if (!sec_def) + return libbpf_err(-ENOMEM); + + custom_sec_defs = sec_def; + sec_def = &custom_sec_defs[custom_sec_def_cnt]; + } else { + if (has_custom_fallback_def) + return libbpf_err(-EBUSY); + + sec_def = &custom_fallback_def; + } + + sec_def->sec = sec ? strdup(sec) : NULL; + if (sec && !sec_def->sec) + return libbpf_err(-ENOMEM); + + sec_def->prog_type = prog_type; + sec_def->expected_attach_type = exp_attach_type; + sec_def->cookie = OPTS_GET(opts, cookie, 0); + + sec_def->prog_setup_fn = OPTS_GET(opts, prog_setup_fn, NULL); + sec_def->prog_prepare_load_fn = OPTS_GET(opts, prog_prepare_load_fn, NULL); + sec_def->prog_attach_fn = OPTS_GET(opts, prog_attach_fn, NULL); + + sec_def->handler_id = ++last_custom_sec_def_handler_id; + + if (sec) + custom_sec_def_cnt++; + else + has_custom_fallback_def = true; + + return sec_def->handler_id; +} + +int libbpf_unregister_prog_handler(int handler_id) +{ + struct bpf_sec_def *sec_defs; + int i; + + if (handler_id <= 0) + return libbpf_err(-EINVAL); + + if (has_custom_fallback_def && custom_fallback_def.handler_id == handler_id) { + memset(&custom_fallback_def, 0, sizeof(custom_fallback_def)); + has_custom_fallback_def = false; + return 0; + } + + for (i = 0; i < custom_sec_def_cnt; i++) { + if (custom_sec_defs[i].handler_id == handler_id) + break; + } + + if (i == custom_sec_def_cnt) + return libbpf_err(-ENOENT); + + free(custom_sec_defs[i].sec); + for (i = i + 1; i < custom_sec_def_cnt; i++) + custom_sec_defs[i - 1] = custom_sec_defs[i]; + custom_sec_def_cnt--; + + /* try to shrink the array, but it's ok if we couldn't */ + sec_defs = libbpf_reallocarray(custom_sec_defs, custom_sec_def_cnt, sizeof(*sec_defs)); + /* if new count is zero, reallocarray can return a valid NULL result; + * in this case the previous pointer will be freed, so we *have to* + * reassign old pointer to the new value (even if it's NULL) + */ + if (sec_defs || custom_sec_def_cnt == 0) + custom_sec_defs = sec_defs; + + return 0; +} + +static bool sec_def_matches(const struct bpf_sec_def *sec_def, const char *sec_name) +{ + size_t len = strlen(sec_def->sec); + + /* "type/" always has to have proper SEC("type/extras") form */ + if (sec_def->sec[len - 1] == '/') { + if (str_has_pfx(sec_name, sec_def->sec)) + return true; + return false; + } + + /* "type+" means it can be either exact SEC("type") or + * well-formed SEC("type/extras") with proper '/' separator + */ + if (sec_def->sec[len - 1] == '+') { + len--; + /* not even a prefix */ + if (strncmp(sec_name, sec_def->sec, len) != 0) + return false; + /* exact match or has '/' separator */ + if (sec_name[len] == '\0' || sec_name[len] == '/') + return true; + return false; + } + + return strcmp(sec_name, sec_def->sec) == 0; +} static const struct bpf_sec_def *find_sec_def(const char *sec_name) { - int i, n = ARRAY_SIZE(section_defs); + const struct bpf_sec_def *sec_def; + int i, n; + n = custom_sec_def_cnt; for (i = 0; i < n; i++) { - if (strncmp(sec_name, - section_defs[i].sec, section_defs[i].len)) - continue; - return §ion_defs[i]; + sec_def = &custom_sec_defs[i]; + if (sec_def_matches(sec_def, sec_name)) + return sec_def; + } + + n = ARRAY_SIZE(section_defs); + for (i = 0; i < n; i++) { + sec_def = §ion_defs[i]; + if (sec_def_matches(sec_def, sec_name)) + return sec_def; } + + if (has_custom_fallback_def) + return &custom_fallback_def; + return NULL; } +#define MAX_TYPE_NAME_SIZE 32 + static char *libbpf_get_type_names(bool attach_type) { int i, len = ARRAY_SIZE(section_defs) * MAX_TYPE_NAME_SIZE; @@ -8408,8 +9489,15 @@ static char *libbpf_get_type_names(bool attach_type) buf[0] = '\0'; /* Forge string buf with all available names */ for (i = 0; i < ARRAY_SIZE(section_defs); i++) { - if (attach_type && !section_defs[i].is_attachable) - continue; + const struct bpf_sec_def *sec_def = §ion_defs[i]; + + if (attach_type) { + if (sec_def->prog_prepare_load_fn != libbpf_prepare_prog_load) + continue; + + if (!(sec_def->cookie & SEC_ATTACHABLE)) + continue; + } if (strlen(buf) + strlen(section_defs[i].sec) + 2 > len) { free(buf); @@ -8429,7 +9517,7 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type, char *type_names; if (!name) - return -EINVAL; + return libbpf_err(-EINVAL); sec_def = find_sec_def(name); if (sec_def) { @@ -8445,10 +9533,43 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type, free(type_names); } - return -ESRCH; + return libbpf_err(-ESRCH); +} + +const char *libbpf_bpf_attach_type_str(enum bpf_attach_type t) +{ + if (t < 0 || t >= ARRAY_SIZE(attach_type_name)) + return NULL; + + return attach_type_name[t]; +} + +const char *libbpf_bpf_link_type_str(enum bpf_link_type t) +{ + if (t < 0 || t >= ARRAY_SIZE(link_type_name)) + return NULL; + + return link_type_name[t]; +} + +const char *libbpf_bpf_map_type_str(enum bpf_map_type t) +{ + if (t < 0 || t >= ARRAY_SIZE(map_type_name)) + return NULL; + + return map_type_name[t]; +} + +const char *libbpf_bpf_prog_type_str(enum bpf_prog_type t) +{ + if (t < 0 || t >= ARRAY_SIZE(prog_type_name)) + return NULL; + + return prog_type_name[t]; } static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj, + int sec_idx, size_t offset) { struct bpf_map *map; @@ -8458,7 +9579,8 @@ static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj, map = &obj->maps[i]; if (!bpf_map__is_struct_ops(map)) continue; - if (map->sec_offset <= offset && + if (map->sec_idx == sec_idx && + map->sec_offset <= offset && offset - map->sec_offset < map->def.value_size) return map; } @@ -8466,9 +9588,11 @@ static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj, return NULL; } -/* Collect the reloc from ELF and populate the st_ops->progs[] */ +/* Collect the reloc from ELF, populate the st_ops->progs[], and update + * st_ops->data for shadow type. + */ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, - GElf_Shdr *shdr, Elf_Data *data) + Elf64_Shdr *shdr, Elf_Data *data) { const struct btf_member *member; struct bpf_struct_ops *st_ops; @@ -8476,58 +9600,58 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, unsigned int shdr_idx; const struct btf *btf; struct bpf_map *map; - Elf_Data *symbols; unsigned int moff, insn_idx; const char *name; __u32 member_idx; - GElf_Sym sym; - GElf_Rel rel; + Elf64_Sym *sym; + Elf64_Rel *rel; int i, nrels; - symbols = obj->efile.symbols; btf = obj->btf; nrels = shdr->sh_size / shdr->sh_entsize; for (i = 0; i < nrels; i++) { - if (!gelf_getrel(data, i, &rel)) { + rel = elf_rel_by_idx(data, i); + if (!rel) { pr_warn("struct_ops reloc: failed to get %d reloc\n", i); return -LIBBPF_ERRNO__FORMAT; } - if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) { + sym = elf_sym_by_idx(obj, ELF64_R_SYM(rel->r_info)); + if (!sym) { pr_warn("struct_ops reloc: symbol %zx not found\n", - (size_t)GELF_R_SYM(rel.r_info)); + (size_t)ELF64_R_SYM(rel->r_info)); return -LIBBPF_ERRNO__FORMAT; } - name = elf_sym_str(obj, sym.st_name) ?: "<?>"; - map = find_struct_ops_map_by_offset(obj, rel.r_offset); + name = elf_sym_str(obj, sym->st_name) ?: "<?>"; + map = find_struct_ops_map_by_offset(obj, shdr->sh_info, rel->r_offset); if (!map) { - pr_warn("struct_ops reloc: cannot find map at rel.r_offset %zu\n", - (size_t)rel.r_offset); + pr_warn("struct_ops reloc: cannot find map at rel->r_offset %zu\n", + (size_t)rel->r_offset); return -EINVAL; } - moff = rel.r_offset - map->sec_offset; - shdr_idx = sym.st_shndx; + moff = rel->r_offset - map->sec_offset; + shdr_idx = sym->st_shndx; st_ops = map->st_ops; - pr_debug("struct_ops reloc %s: for %lld value %lld shdr_idx %u rel.r_offset %zu map->sec_offset %zu name %d (\'%s\')\n", + pr_debug("struct_ops reloc %s: for %lld value %lld shdr_idx %u rel->r_offset %zu map->sec_offset %zu name %d (\'%s\')\n", map->name, - (long long)(rel.r_info >> 32), - (long long)sym.st_value, - shdr_idx, (size_t)rel.r_offset, - map->sec_offset, sym.st_name, name); + (long long)(rel->r_info >> 32), + (long long)sym->st_value, + shdr_idx, (size_t)rel->r_offset, + map->sec_offset, sym->st_name, name); if (shdr_idx >= SHN_LORESERVE) { - pr_warn("struct_ops reloc %s: rel.r_offset %zu shdr_idx %u unsupported non-static function\n", - map->name, (size_t)rel.r_offset, shdr_idx); + pr_warn("struct_ops reloc %s: rel->r_offset %zu shdr_idx %u unsupported non-static function\n", + map->name, (size_t)rel->r_offset, shdr_idx); return -LIBBPF_ERRNO__RELOC; } - if (sym.st_value % BPF_INSN_SZ) { + if (sym->st_value % BPF_INSN_SZ) { pr_warn("struct_ops reloc %s: invalid target program offset %llu\n", - map->name, (unsigned long long)sym.st_value); + map->name, (unsigned long long)sym->st_value); return -LIBBPF_ERRNO__FORMAT; } - insn_idx = sym.st_value / BPF_INSN_SZ; + insn_idx = sym->st_value / BPF_INSN_SZ; member = find_member_by_offset(st_ops->type, moff * 8); if (!member) { @@ -8551,35 +9675,25 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, return -EINVAL; } - if (prog->type == BPF_PROG_TYPE_UNSPEC) { - const struct bpf_sec_def *sec_def; - - sec_def = find_sec_def(prog->sec_name); - if (sec_def && - sec_def->prog_type != BPF_PROG_TYPE_STRUCT_OPS) { - /* for pr_warn */ - prog->type = sec_def->prog_type; - goto invalid_prog; - } - - prog->type = BPF_PROG_TYPE_STRUCT_OPS; - prog->attach_btf_id = st_ops->type_id; - prog->expected_attach_type = member_idx; - } else if (prog->type != BPF_PROG_TYPE_STRUCT_OPS || - prog->attach_btf_id != st_ops->type_id || - prog->expected_attach_type != member_idx) { - goto invalid_prog; + /* prevent the use of BPF prog with invalid type */ + if (prog->type != BPF_PROG_TYPE_STRUCT_OPS) { + pr_warn("struct_ops reloc %s: prog %s is not struct_ops BPF program\n", + map->name, prog->name); + return -EINVAL; } + st_ops->progs[member_idx] = prog; + + /* st_ops->data will be exposed to users, being returned by + * bpf_map__initial_value() as a pointer to the shadow + * type. All function pointers in the original struct type + * should be converted to a pointer to struct bpf_program + * in the shadow type. + */ + *((struct bpf_program **)(st_ops->data + moff)) = prog; } return 0; - -invalid_prog: - pr_warn("struct_ops reloc %s: cannot use prog %s in sec %s with type %u attach_btf_id %u expected_attach_type %u for func ptr %s\n", - map->name, prog->name, prog->sec_name, prog->type, - prog->attach_btf_id, prog->expected_attach_type, name); - return -EINVAL; } #define BTF_TRACE_PREFIX "btf_trace_" @@ -8587,6 +9701,29 @@ invalid_prog: #define BTF_ITER_PREFIX "bpf_iter_" #define BTF_MAX_NAME_SIZE 128 +void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type, + const char **prefix, int *kind) +{ + switch (attach_type) { + case BPF_TRACE_RAW_TP: + *prefix = BTF_TRACE_PREFIX; + *kind = BTF_KIND_TYPEDEF; + break; + case BPF_LSM_MAC: + case BPF_LSM_CGROUP: + *prefix = BTF_LSM_PREFIX; + *kind = BTF_KIND_FUNC; + break; + case BPF_TRACE_ITER: + *prefix = BTF_ITER_PREFIX; + *kind = BTF_KIND_FUNC; + break; + default: + *prefix = ""; + *kind = BTF_KIND_FUNC; + } +} + static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, const char *name, __u32 kind) { @@ -8596,7 +9733,7 @@ static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, ret = snprintf(btf_type_name, sizeof(btf_type_name), "%s%s", prefix, name); /* snprintf returns the number of characters written excluding the - * the terminating null. So, if >= BTF_MAX_NAME_SIZE are written, it + * terminating null. So, if >= BTF_MAX_NAME_SIZE are written, it * indicates truncation. */ if (ret < 0 || ret >= sizeof(btf_type_name)) @@ -8604,27 +9741,14 @@ static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, return btf__find_by_name_kind(btf, btf_type_name, kind); } -static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name, - enum bpf_attach_type attach_type) +static inline int find_attach_btf_id(struct btf *btf, const char *name, + enum bpf_attach_type attach_type) { - int err; - - if (attach_type == BPF_TRACE_RAW_TP) - err = find_btf_by_prefix_kind(btf, BTF_TRACE_PREFIX, name, - BTF_KIND_TYPEDEF); - else if (attach_type == BPF_LSM_MAC) - err = find_btf_by_prefix_kind(btf, BTF_LSM_PREFIX, name, - BTF_KIND_FUNC); - else if (attach_type == BPF_TRACE_ITER) - err = find_btf_by_prefix_kind(btf, BTF_ITER_PREFIX, name, - BTF_KIND_FUNC); - else - err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC); - - if (err <= 0) - pr_warn("%s is not found in vmlinux BTF\n", name); + const char *prefix; + int kind; - return err; + btf_get_kernel_prefix_kind(attach_type, &prefix, &kind); + return find_btf_by_prefix_kind(btf, prefix, name, kind); } int libbpf_find_vmlinux_btf_id(const char *name, @@ -8633,37 +9757,45 @@ int libbpf_find_vmlinux_btf_id(const char *name, struct btf *btf; int err; - btf = libbpf_find_kernel_btf(); - if (IS_ERR(btf)) { + btf = btf__load_vmlinux_btf(); + err = libbpf_get_error(btf); + if (err) { pr_warn("vmlinux BTF is not found\n"); - return -EINVAL; + return libbpf_err(err); } - err = __find_vmlinux_btf_id(btf, name, attach_type); + err = find_attach_btf_id(btf, name, attach_type); + if (err <= 0) + pr_warn("%s is not found in vmlinux BTF\n", name); + btf__free(btf); - return err; + return libbpf_err(err); } static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd) { - struct bpf_prog_info_linear *info_linear; - struct bpf_prog_info *info; - struct btf *btf = NULL; - int err = -EINVAL; + struct bpf_prog_info info; + __u32 info_len = sizeof(info); + struct btf *btf; + int err; - info_linear = bpf_program__get_prog_info_linear(attach_prog_fd, 0); - if (IS_ERR_OR_NULL(info_linear)) { - pr_warn("failed get_prog_info_linear for FD %d\n", - attach_prog_fd); - return -EINVAL; + memset(&info, 0, info_len); + err = bpf_prog_get_info_by_fd(attach_prog_fd, &info, &info_len); + if (err) { + pr_warn("failed bpf_prog_get_info_by_fd for FD %d: %d\n", + attach_prog_fd, err); + return err; } - info = &info_linear->info; - if (!info->btf_id) { + + err = -EINVAL; + if (!info.btf_id) { pr_warn("The target program doesn't have BTF\n"); goto out; } - if (btf__get_from_id(info->btf_id, &btf)) { - pr_warn("Failed to get BTF of the program\n"); + btf = btf__load_from_kernel_by_id(info.btf_id); + err = libbpf_get_error(btf); + if (err) { + pr_warn("Failed to get BTF %d of the program: %d\n", info.btf_id, err); goto out; } err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC); @@ -8673,78 +9805,151 @@ static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd) goto out; } out: - free(info_linear); return err; } -static int libbpf_find_attach_btf_id(struct bpf_program *prog) +static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name, + enum bpf_attach_type attach_type, + int *btf_obj_fd, int *btf_type_id) +{ + int ret, i; + + ret = find_attach_btf_id(obj->btf_vmlinux, attach_name, attach_type); + if (ret > 0) { + *btf_obj_fd = 0; /* vmlinux BTF */ + *btf_type_id = ret; + return 0; + } + if (ret != -ENOENT) + return ret; + + ret = load_module_btfs(obj); + if (ret) + return ret; + + for (i = 0; i < obj->btf_module_cnt; i++) { + const struct module_btf *mod = &obj->btf_modules[i]; + + ret = find_attach_btf_id(mod->btf, attach_name, attach_type); + if (ret > 0) { + *btf_obj_fd = mod->fd; + *btf_type_id = ret; + return 0; + } + if (ret == -ENOENT) + continue; + + return ret; + } + + return -ESRCH; +} + +static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attach_name, + int *btf_obj_fd, int *btf_type_id) { enum bpf_attach_type attach_type = prog->expected_attach_type; __u32 attach_prog_fd = prog->attach_prog_fd; - const char *name = prog->sec_name; - int i, err; + int err = 0; - if (!name) - return -EINVAL; + /* BPF program's BTF ID */ + if (prog->type == BPF_PROG_TYPE_EXT || attach_prog_fd) { + if (!attach_prog_fd) { + pr_warn("prog '%s': attach program FD is not set\n", prog->name); + return -EINVAL; + } + err = libbpf_find_prog_btf_id(attach_name, attach_prog_fd); + if (err < 0) { + pr_warn("prog '%s': failed to find BPF program (FD %d) BTF ID for '%s': %d\n", + prog->name, attach_prog_fd, attach_name, err); + return err; + } + *btf_obj_fd = 0; + *btf_type_id = err; + return 0; + } - for (i = 0; i < ARRAY_SIZE(section_defs); i++) { - if (!section_defs[i].is_attach_btf) - continue; - if (strncmp(name, section_defs[i].sec, section_defs[i].len)) - continue; - if (attach_prog_fd) - err = libbpf_find_prog_btf_id(name + section_defs[i].len, - attach_prog_fd); - else - err = __find_vmlinux_btf_id(prog->obj->btf_vmlinux, - name + section_defs[i].len, - attach_type); + /* kernel/module BTF ID */ + if (prog->obj->gen_loader) { + bpf_gen__record_attach_target(prog->obj->gen_loader, attach_name, attach_type); + *btf_obj_fd = 0; + *btf_type_id = 1; + } else { + err = find_kernel_btf_id(prog->obj, attach_name, + attach_type, btf_obj_fd, + btf_type_id); + } + if (err) { + pr_warn("prog '%s': failed to find kernel BTF type ID of '%s': %d\n", + prog->name, attach_name, err); return err; } - pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name); - return -ESRCH; + return 0; } int libbpf_attach_type_by_name(const char *name, enum bpf_attach_type *attach_type) { char *type_names; - int i; + const struct bpf_sec_def *sec_def; if (!name) - return -EINVAL; + return libbpf_err(-EINVAL); - for (i = 0; i < ARRAY_SIZE(section_defs); i++) { - if (strncmp(name, section_defs[i].sec, section_defs[i].len)) - continue; - if (!section_defs[i].is_attachable) - return -EINVAL; - *attach_type = section_defs[i].expected_attach_type; - return 0; - } - pr_debug("failed to guess attach type based on ELF section name '%s'\n", name); - type_names = libbpf_get_type_names(true); - if (type_names != NULL) { - pr_debug("attachable section(type) names are:%s\n", type_names); - free(type_names); + sec_def = find_sec_def(name); + if (!sec_def) { + pr_debug("failed to guess attach type based on ELF section name '%s'\n", name); + type_names = libbpf_get_type_names(true); + if (type_names != NULL) { + pr_debug("attachable section(type) names are:%s\n", type_names); + free(type_names); + } + + return libbpf_err(-EINVAL); } - return -EINVAL; + if (sec_def->prog_prepare_load_fn != libbpf_prepare_prog_load) + return libbpf_err(-EINVAL); + if (!(sec_def->cookie & SEC_ATTACHABLE)) + return libbpf_err(-EINVAL); + + *attach_type = sec_def->expected_attach_type; + return 0; } int bpf_map__fd(const struct bpf_map *map) { - return map ? map->fd : -EINVAL; + if (!map) + return libbpf_err(-EINVAL); + if (!map_is_created(map)) + return -1; + return map->fd; } -const struct bpf_map_def *bpf_map__def(const struct bpf_map *map) +static bool map_uses_real_name(const struct bpf_map *map) { - return map ? &map->def : ERR_PTR(-EINVAL); + /* Since libbpf started to support custom .data.* and .rodata.* maps, + * their user-visible name differs from kernel-visible name. Users see + * such map's corresponding ELF section name as a map name. + * This check distinguishes .data/.rodata from .data.* and .rodata.* + * maps to know which name has to be returned to the user. + */ + if (map->libbpf_type == LIBBPF_MAP_DATA && strcmp(map->real_name, DATA_SEC) != 0) + return true; + if (map->libbpf_type == LIBBPF_MAP_RODATA && strcmp(map->real_name, RODATA_SEC) != 0) + return true; + return false; } const char *bpf_map__name(const struct bpf_map *map) { - return map ? map->name : NULL; + if (!map) + return NULL; + + if (map_uses_real_name(map)) + return map->real_name; + + return map->name; } enum bpf_map_type bpf_map__type(const struct bpf_map *map) @@ -8754,8 +9959,8 @@ enum bpf_map_type bpf_map__type(const struct bpf_map *map) int bpf_map__set_type(struct bpf_map *map, enum bpf_map_type type) { - if (map->fd >= 0) - return -EBUSY; + if (map_is_created(map)) + return libbpf_err(-EBUSY); map->def.type = type; return 0; } @@ -8767,12 +9972,25 @@ __u32 bpf_map__map_flags(const struct bpf_map *map) int bpf_map__set_map_flags(struct bpf_map *map, __u32 flags) { - if (map->fd >= 0) - return -EBUSY; + if (map_is_created(map)) + return libbpf_err(-EBUSY); map->def.map_flags = flags; return 0; } +__u64 bpf_map__map_extra(const struct bpf_map *map) +{ + return map->map_extra; +} + +int bpf_map__set_map_extra(struct bpf_map *map, __u64 map_extra) +{ + if (map_is_created(map)) + return libbpf_err(-EBUSY); + map->map_extra = map_extra; + return 0; +} + __u32 bpf_map__numa_node(const struct bpf_map *map) { return map->numa_node; @@ -8780,8 +9998,8 @@ __u32 bpf_map__numa_node(const struct bpf_map *map) int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node) { - if (map->fd >= 0) - return -EBUSY; + if (map_is_created(map)) + return libbpf_err(-EBUSY); map->numa_node = numa_node; return 0; } @@ -8793,8 +10011,8 @@ __u32 bpf_map__key_size(const struct bpf_map *map) int bpf_map__set_key_size(struct bpf_map *map, __u32 size) { - if (map->fd >= 0) - return -EBUSY; + if (map_is_created(map)) + return libbpf_err(-EBUSY); map->def.key_size = size; return 0; } @@ -8804,10 +10022,106 @@ __u32 bpf_map__value_size(const struct bpf_map *map) return map->def.value_size; } +static int map_btf_datasec_resize(struct bpf_map *map, __u32 size) +{ + struct btf *btf; + struct btf_type *datasec_type, *var_type; + struct btf_var_secinfo *var; + const struct btf_type *array_type; + const struct btf_array *array; + int vlen, element_sz, new_array_id; + __u32 nr_elements; + + /* check btf existence */ + btf = bpf_object__btf(map->obj); + if (!btf) + return -ENOENT; + + /* verify map is datasec */ + datasec_type = btf_type_by_id(btf, bpf_map__btf_value_type_id(map)); + if (!btf_is_datasec(datasec_type)) { + pr_warn("map '%s': cannot be resized, map value type is not a datasec\n", + bpf_map__name(map)); + return -EINVAL; + } + + /* verify datasec has at least one var */ + vlen = btf_vlen(datasec_type); + if (vlen == 0) { + pr_warn("map '%s': cannot be resized, map value datasec is empty\n", + bpf_map__name(map)); + return -EINVAL; + } + + /* verify last var in the datasec is an array */ + var = &btf_var_secinfos(datasec_type)[vlen - 1]; + var_type = btf_type_by_id(btf, var->type); + array_type = skip_mods_and_typedefs(btf, var_type->type, NULL); + if (!btf_is_array(array_type)) { + pr_warn("map '%s': cannot be resized, last var must be an array\n", + bpf_map__name(map)); + return -EINVAL; + } + + /* verify request size aligns with array */ + array = btf_array(array_type); + element_sz = btf__resolve_size(btf, array->type); + if (element_sz <= 0 || (size - var->offset) % element_sz != 0) { + pr_warn("map '%s': cannot be resized, element size (%d) doesn't align with new total size (%u)\n", + bpf_map__name(map), element_sz, size); + return -EINVAL; + } + + /* create a new array based on the existing array, but with new length */ + nr_elements = (size - var->offset) / element_sz; + new_array_id = btf__add_array(btf, array->index_type, array->type, nr_elements); + if (new_array_id < 0) + return new_array_id; + + /* adding a new btf type invalidates existing pointers to btf objects, + * so refresh pointers before proceeding + */ + datasec_type = btf_type_by_id(btf, map->btf_value_type_id); + var = &btf_var_secinfos(datasec_type)[vlen - 1]; + var_type = btf_type_by_id(btf, var->type); + + /* finally update btf info */ + datasec_type->size = size; + var->size = size - var->offset; + var_type->type = new_array_id; + + return 0; +} + int bpf_map__set_value_size(struct bpf_map *map, __u32 size) { - if (map->fd >= 0) - return -EBUSY; + if (map->obj->loaded || map->reused) + return libbpf_err(-EBUSY); + + if (map->mmaped) { + size_t mmap_old_sz, mmap_new_sz; + int err; + + if (map->def.type != BPF_MAP_TYPE_ARRAY) + return -EOPNOTSUPP; + + mmap_old_sz = bpf_map_mmap_sz(map); + mmap_new_sz = array_map_mmap_sz(size, map->def.max_entries); + err = bpf_map_mmap_resize(map, mmap_old_sz, mmap_new_sz); + if (err) { + pr_warn("map '%s': failed to resize memory-mapped region: %d\n", + bpf_map__name(map), err); + return err; + } + err = map_btf_datasec_resize(map, size); + if (err && err != -ENOENT) { + pr_warn("map '%s': failed to adjust resized BTF, clearing BTF key/value info: %d\n", + bpf_map__name(map), err); + map->btf_value_type_id = 0; + map->btf_key_type_id = 0; + } + } + map->def.value_size = size; return 0; } @@ -8822,41 +10136,45 @@ __u32 bpf_map__btf_value_type_id(const struct bpf_map *map) return map ? map->btf_value_type_id : 0; } -int bpf_map__set_priv(struct bpf_map *map, void *priv, - bpf_map_clear_priv_t clear_priv) +int bpf_map__set_initial_value(struct bpf_map *map, + const void *data, size_t size) { - if (!map) - return -EINVAL; + size_t actual_sz; - if (map->priv) { - if (map->clear_priv) - map->clear_priv(map, map->priv); - } + if (map->obj->loaded || map->reused) + return libbpf_err(-EBUSY); - map->priv = priv; - map->clear_priv = clear_priv; - return 0; -} - -void *bpf_map__priv(const struct bpf_map *map) -{ - return map ? map->priv : ERR_PTR(-EINVAL); -} + if (!map->mmaped || map->libbpf_type == LIBBPF_MAP_KCONFIG) + return libbpf_err(-EINVAL); -int bpf_map__set_initial_value(struct bpf_map *map, - const void *data, size_t size) -{ - if (!map->mmaped || map->libbpf_type == LIBBPF_MAP_KCONFIG || - size != map->def.value_size || map->fd >= 0) - return -EINVAL; + if (map->def.type == BPF_MAP_TYPE_ARENA) + actual_sz = map->obj->arena_data_sz; + else + actual_sz = map->def.value_size; + if (size != actual_sz) + return libbpf_err(-EINVAL); memcpy(map->mmaped, data, size); return 0; } -bool bpf_map__is_offload_neutral(const struct bpf_map *map) +void *bpf_map__initial_value(const struct bpf_map *map, size_t *psize) { - return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY; + if (bpf_map__is_struct_ops(map)) { + if (psize) + *psize = map->def.value_size; + return map->st_ops->data; + } + + if (!map->mmaped) + return NULL; + + if (map->def.type == BPF_MAP_TYPE_ARENA) + *psize = map->obj->arena_data_sz; + else + *psize = map->def.value_size; + + return map->mmaped; } bool bpf_map__is_internal(const struct bpf_map *map) @@ -8871,8 +10189,8 @@ __u32 bpf_map__ifindex(const struct bpf_map *map) int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex) { - if (map->fd >= 0) - return -EBUSY; + if (map_is_created(map)) + return libbpf_err(-EBUSY); map->map_ifindex = ifindex; return 0; } @@ -8881,11 +10199,15 @@ int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd) { if (!bpf_map_type__is_map_in_map(map->def.type)) { pr_warn("error: unsupported map type\n"); - return -EINVAL; + return libbpf_err(-EINVAL); } if (map->inner_map_fd != -1) { pr_warn("error: inner_map_fd already specified\n"); - return -EINVAL; + return libbpf_err(-EINVAL); + } + if (map->inner_map) { + bpf_map__destroy(map->inner_map); + zfree(&map->inner_map); } map->inner_map_fd = fd; return 0; @@ -8898,7 +10220,7 @@ __bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i) struct bpf_map *s, *e; if (!obj || !obj->maps) - return NULL; + return errno = EINVAL, NULL; s = obj->maps; e = obj->maps + obj->nr_maps; @@ -8906,7 +10228,7 @@ __bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i) if ((m < s) || (m >= e)) { pr_warn("error in %s: map handler doesn't belong to object\n", __func__); - return NULL; + return errno = EINVAL, NULL; } idx = (m - obj->maps) + i; @@ -8916,7 +10238,7 @@ __bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i) } struct bpf_map * -bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj) +bpf_object__next_map(const struct bpf_object *obj, const struct bpf_map *prev) { if (prev == NULL) return obj->maps; @@ -8925,7 +10247,7 @@ bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj) } struct bpf_map * -bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj) +bpf_object__prev_map(const struct bpf_object *obj, const struct bpf_map *next) { if (next == NULL) { if (!obj->nr_maps) @@ -8942,10 +10264,25 @@ bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name) struct bpf_map *pos; bpf_object__for_each_map(pos, obj) { - if (pos->name && !strcmp(pos->name, name)) + /* if it's a special internal map name (which always starts + * with dot) then check if that special name matches the + * real map name (ELF section name) + */ + if (name[0] == '.') { + if (pos->real_name && strcmp(pos->real_name, name) == 0) + return pos; + continue; + } + /* otherwise map name has to be an exact match */ + if (map_uses_real_name(pos)) { + if (strcmp(pos->real_name, name) == 0) + return pos; + continue; + } + if (strcmp(pos->name, name) == 0) return pos; } - return NULL; + return errno = ENOENT, NULL; } int @@ -8954,113 +10291,133 @@ bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name) return bpf_map__fd(bpf_object__find_map_by_name(obj, name)); } -struct bpf_map * -bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset) +static int validate_map_op(const struct bpf_map *map, size_t key_sz, + size_t value_sz, bool check_value_sz) { - return ERR_PTR(-ENOTSUP); + if (!map_is_created(map)) /* map is not yet created */ + return -ENOENT; + + if (map->def.key_size != key_sz) { + pr_warn("map '%s': unexpected key size %zu provided, expected %u\n", + map->name, key_sz, map->def.key_size); + return -EINVAL; + } + + if (!check_value_sz) + return 0; + + switch (map->def.type) { + case BPF_MAP_TYPE_PERCPU_ARRAY: + case BPF_MAP_TYPE_PERCPU_HASH: + case BPF_MAP_TYPE_LRU_PERCPU_HASH: + case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: { + int num_cpu = libbpf_num_possible_cpus(); + size_t elem_sz = roundup(map->def.value_size, 8); + + if (value_sz != num_cpu * elem_sz) { + pr_warn("map '%s': unexpected value size %zu provided for per-CPU map, expected %d * %zu = %zd\n", + map->name, value_sz, num_cpu, elem_sz, num_cpu * elem_sz); + return -EINVAL; + } + break; + } + default: + if (map->def.value_size != value_sz) { + pr_warn("map '%s': unexpected value size %zu provided, expected %u\n", + map->name, value_sz, map->def.value_size); + return -EINVAL; + } + break; + } + return 0; } -long libbpf_get_error(const void *ptr) +int bpf_map__lookup_elem(const struct bpf_map *map, + const void *key, size_t key_sz, + void *value, size_t value_sz, __u64 flags) { - return PTR_ERR_OR_ZERO(ptr); + int err; + + err = validate_map_op(map, key_sz, value_sz, true); + if (err) + return libbpf_err(err); + + return bpf_map_lookup_elem_flags(map->fd, key, value, flags); } -int bpf_prog_load(const char *file, enum bpf_prog_type type, - struct bpf_object **pobj, int *prog_fd) +int bpf_map__update_elem(const struct bpf_map *map, + const void *key, size_t key_sz, + const void *value, size_t value_sz, __u64 flags) { - struct bpf_prog_load_attr attr; + int err; - memset(&attr, 0, sizeof(struct bpf_prog_load_attr)); - attr.file = file; - attr.prog_type = type; - attr.expected_attach_type = 0; + err = validate_map_op(map, key_sz, value_sz, true); + if (err) + return libbpf_err(err); - return bpf_prog_load_xattr(&attr, pobj, prog_fd); + return bpf_map_update_elem(map->fd, key, value, flags); } -int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr, - struct bpf_object **pobj, int *prog_fd) +int bpf_map__delete_elem(const struct bpf_map *map, + const void *key, size_t key_sz, __u64 flags) { - struct bpf_object_open_attr open_attr = {}; - struct bpf_program *prog, *first_prog = NULL; - struct bpf_object *obj; - struct bpf_map *map; int err; - if (!attr) - return -EINVAL; - if (!attr->file) - return -EINVAL; - - open_attr.file = attr->file; - open_attr.prog_type = attr->prog_type; + err = validate_map_op(map, key_sz, 0, false /* check_value_sz */); + if (err) + return libbpf_err(err); - obj = bpf_object__open_xattr(&open_attr); - if (IS_ERR_OR_NULL(obj)) - return -ENOENT; + return bpf_map_delete_elem_flags(map->fd, key, flags); +} - bpf_object__for_each_program(prog, obj) { - enum bpf_attach_type attach_type = attr->expected_attach_type; - /* - * to preserve backwards compatibility, bpf_prog_load treats - * attr->prog_type, if specified, as an override to whatever - * bpf_object__open guessed - */ - if (attr->prog_type != BPF_PROG_TYPE_UNSPEC) { - bpf_program__set_type(prog, attr->prog_type); - bpf_program__set_expected_attach_type(prog, - attach_type); - } - if (bpf_program__get_type(prog) == BPF_PROG_TYPE_UNSPEC) { - /* - * we haven't guessed from section name and user - * didn't provide a fallback type, too bad... - */ - bpf_object__close(obj); - return -EINVAL; - } +int bpf_map__lookup_and_delete_elem(const struct bpf_map *map, + const void *key, size_t key_sz, + void *value, size_t value_sz, __u64 flags) +{ + int err; - prog->prog_ifindex = attr->ifindex; - prog->log_level = attr->log_level; - prog->prog_flags |= attr->prog_flags; - if (!first_prog) - first_prog = prog; - } + err = validate_map_op(map, key_sz, value_sz, true); + if (err) + return libbpf_err(err); - bpf_object__for_each_map(map, obj) { - if (!bpf_map__is_offload_neutral(map)) - map->map_ifindex = attr->ifindex; - } + return bpf_map_lookup_and_delete_elem_flags(map->fd, key, value, flags); +} - if (!first_prog) { - pr_warn("object file doesn't contain bpf program\n"); - bpf_object__close(obj); - return -ENOENT; - } +int bpf_map__get_next_key(const struct bpf_map *map, + const void *cur_key, void *next_key, size_t key_sz) +{ + int err; - err = bpf_object__load(obj); - if (err) { - bpf_object__close(obj); - return err; - } + err = validate_map_op(map, key_sz, 0, false /* check_value_sz */); + if (err) + return libbpf_err(err); - *pobj = obj; - *prog_fd = bpf_program__fd(first_prog); - return 0; + return bpf_map_get_next_key(map->fd, cur_key, next_key); } -struct bpf_link { - int (*detach)(struct bpf_link *link); - int (*destroy)(struct bpf_link *link); - char *pin_path; /* NULL, if not pinned */ - int fd; /* hook FD, -1 if not applicable */ - bool disconnected; -}; +long libbpf_get_error(const void *ptr) +{ + if (!IS_ERR_OR_NULL(ptr)) + return 0; + + if (IS_ERR(ptr)) + errno = -PTR_ERR(ptr); + + /* If ptr == NULL, then errno should be already set by the failing + * API, because libbpf never returns NULL on success and it now always + * sets errno on error. So no extra errno handling for ptr == NULL + * case. + */ + return -errno; +} /* Replace link's underlying BPF program with the new one */ int bpf_link__update_program(struct bpf_link *link, struct bpf_program *prog) { - return bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), NULL); + int ret; + + ret = bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), NULL); + return libbpf_err_errno(ret); } /* Release "ownership" of underlying BPF resource (typically, BPF program @@ -9087,13 +10444,14 @@ int bpf_link__destroy(struct bpf_link *link) if (!link->disconnected && link->detach) err = link->detach(link); - if (link->destroy) - link->destroy(link); if (link->pin_path) free(link->pin_path); - free(link); + if (link->dealloc) + link->dealloc(link); + else + free(link); - return err; + return libbpf_err(err); } int bpf_link__fd(const struct bpf_link *link) @@ -9108,7 +10466,7 @@ const char *bpf_link__pin_path(const struct bpf_link *link) static int bpf_link__detach_fd(struct bpf_link *link) { - return close(link->fd); + return libbpf_err_errno(close(link->fd)); } struct bpf_link *bpf_link__open(const char *path) @@ -9120,13 +10478,13 @@ struct bpf_link *bpf_link__open(const char *path) if (fd < 0) { fd = -errno; pr_warn("failed to open link at %s: %d\n", path, fd); - return ERR_PTR(fd); + return libbpf_err_ptr(fd); } link = calloc(1, sizeof(*link)); if (!link) { close(fd); - return ERR_PTR(-ENOMEM); + return libbpf_err_ptr(-ENOMEM); } link->detach = &bpf_link__detach_fd; link->fd = fd; @@ -9134,7 +10492,7 @@ struct bpf_link *bpf_link__open(const char *path) link->pin_path = strdup(path); if (!link->pin_path) { bpf_link__destroy(link); - return ERR_PTR(-ENOMEM); + return libbpf_err_ptr(-ENOMEM); } return link; @@ -9150,22 +10508,22 @@ int bpf_link__pin(struct bpf_link *link, const char *path) int err; if (link->pin_path) - return -EBUSY; + return libbpf_err(-EBUSY); err = make_parent_dir(path); if (err) - return err; + return libbpf_err(err); err = check_path(path); if (err) - return err; + return libbpf_err(err); link->pin_path = strdup(path); if (!link->pin_path) - return -ENOMEM; + return libbpf_err(-ENOMEM); if (bpf_obj_pin(link->fd, link->pin_path)) { err = -errno; zfree(&link->pin_path); - return err; + return libbpf_err(err); } pr_debug("link fd=%d: pinned at %s\n", link->fd, link->pin_path); @@ -9177,7 +10535,7 @@ int bpf_link__unpin(struct bpf_link *link) int err; if (!link->pin_path) - return -EINVAL; + return libbpf_err(-EINVAL); err = unlink(link->pin_path); if (err != 0) @@ -9188,61 +10546,132 @@ int bpf_link__unpin(struct bpf_link *link) return 0; } -static int bpf_link__detach_perf_event(struct bpf_link *link) +struct bpf_link_perf { + struct bpf_link link; + int perf_event_fd; + /* legacy kprobe support: keep track of probe identifier and type */ + char *legacy_probe_name; + bool legacy_is_kprobe; + bool legacy_is_retprobe; +}; + +static int remove_kprobe_event_legacy(const char *probe_name, bool retprobe); +static int remove_uprobe_event_legacy(const char *probe_name, bool retprobe); + +static int bpf_link_perf_detach(struct bpf_link *link) { - int err; + struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); + int err = 0; - err = ioctl(link->fd, PERF_EVENT_IOC_DISABLE, 0); - if (err) + if (ioctl(perf_link->perf_event_fd, PERF_EVENT_IOC_DISABLE, 0) < 0) err = -errno; + if (perf_link->perf_event_fd != link->fd) + close(perf_link->perf_event_fd); close(link->fd); + + /* legacy uprobe/kprobe needs to be removed after perf event fd closure */ + if (perf_link->legacy_probe_name) { + if (perf_link->legacy_is_kprobe) { + err = remove_kprobe_event_legacy(perf_link->legacy_probe_name, + perf_link->legacy_is_retprobe); + } else { + err = remove_uprobe_event_legacy(perf_link->legacy_probe_name, + perf_link->legacy_is_retprobe); + } + } + return err; } -struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog, - int pfd) +static void bpf_link_perf_dealloc(struct bpf_link *link) +{ + struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); + + free(perf_link->legacy_probe_name); + free(perf_link); +} + +struct bpf_link *bpf_program__attach_perf_event_opts(const struct bpf_program *prog, int pfd, + const struct bpf_perf_event_opts *opts) { char errmsg[STRERR_BUFSIZE]; - struct bpf_link *link; - int prog_fd, err; + struct bpf_link_perf *link; + int prog_fd, link_fd = -1, err; + bool force_ioctl_attach; + + if (!OPTS_VALID(opts, bpf_perf_event_opts)) + return libbpf_err_ptr(-EINVAL); if (pfd < 0) { pr_warn("prog '%s': invalid perf event FD %d\n", prog->name, pfd); - return ERR_PTR(-EINVAL); + return libbpf_err_ptr(-EINVAL); } prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach BPF program w/o FD (did you load it?)\n", prog->name); - return ERR_PTR(-EINVAL); + return libbpf_err_ptr(-EINVAL); } link = calloc(1, sizeof(*link)); if (!link) - return ERR_PTR(-ENOMEM); - link->detach = &bpf_link__detach_perf_event; - link->fd = pfd; + return libbpf_err_ptr(-ENOMEM); + link->link.detach = &bpf_link_perf_detach; + link->link.dealloc = &bpf_link_perf_dealloc; + link->perf_event_fd = pfd; + + force_ioctl_attach = OPTS_GET(opts, force_ioctl_attach, false); + if (kernel_supports(prog->obj, FEAT_PERF_LINK) && !force_ioctl_attach) { + DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_opts, + .perf_event.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0)); + + link_fd = bpf_link_create(prog_fd, pfd, BPF_PERF_EVENT, &link_opts); + if (link_fd < 0) { + err = -errno; + pr_warn("prog '%s': failed to create BPF link for perf_event FD %d: %d (%s)\n", + prog->name, pfd, + err, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto err_out; + } + link->link.fd = link_fd; + } else { + if (OPTS_GET(opts, bpf_cookie, 0)) { + pr_warn("prog '%s': user context value is not supported\n", prog->name); + err = -EOPNOTSUPP; + goto err_out; + } - if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) { - err = -errno; - free(link); - pr_warn("prog '%s': failed to attach to pfd %d: %s\n", - prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); - if (err == -EPROTO) - pr_warn("prog '%s': try add PERF_SAMPLE_CALLCHAIN to or remove exclude_callchain_[kernel|user] from pfd %d\n", - prog->name, pfd); - return ERR_PTR(err); + if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) { + err = -errno; + pr_warn("prog '%s': failed to attach to perf_event FD %d: %s\n", + prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + if (err == -EPROTO) + pr_warn("prog '%s': try add PERF_SAMPLE_CALLCHAIN to or remove exclude_callchain_[kernel|user] from pfd %d\n", + prog->name, pfd); + goto err_out; + } + link->link.fd = pfd; } if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) { err = -errno; - free(link); - pr_warn("prog '%s': failed to enable pfd %d: %s\n", + pr_warn("prog '%s': failed to enable perf_event FD %d: %s\n", prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); - return ERR_PTR(err); + goto err_out; } - return link; + + return &link->link; +err_out: + if (link_fd >= 0) + close(link_fd); + free(link); + return libbpf_err_ptr(err); +} + +struct bpf_link *bpf_program__attach_perf_event(const struct bpf_program *prog, int pfd) +{ + return bpf_program__attach_perf_event_opts(prog, pfd, NULL); } /* @@ -9256,7 +10685,7 @@ static int parse_uint_from_file(const char *file, const char *fmt) int err, ret; FILE *f; - f = fopen(file, "r"); + f = fopen(file, "re"); if (!f) { err = -errno; pr_debug("failed to open '%s': %s\n", file, @@ -9303,12 +10732,21 @@ static int determine_uprobe_retprobe_bit(void) return parse_uint_from_file(file, "config:%d\n"); } +#define PERF_UPROBE_REF_CTR_OFFSET_BITS 32 +#define PERF_UPROBE_REF_CTR_OFFSET_SHIFT 32 + static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name, - uint64_t offset, int pid) + uint64_t offset, int pid, size_t ref_ctr_off) { - struct perf_event_attr attr = {}; + const size_t attr_sz = sizeof(struct perf_event_attr); + struct perf_event_attr attr; char errmsg[STRERR_BUFSIZE]; - int type, pfd, err; + int type, pfd; + + if ((__u64)ref_ctr_off >= (1ULL << PERF_UPROBE_REF_CTR_OFFSET_BITS)) + return -EINVAL; + + memset(&attr, 0, attr_sz); type = uprobe ? determine_uprobe_perf_type() : determine_kprobe_perf_type(); @@ -9330,8 +10768,9 @@ static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name, } attr.config |= 1 << bit; } - attr.size = sizeof(attr); + attr.size = attr_sz; attr.type = type; + attr.config |= (__u64)ref_ctr_off << PERF_UPROBE_REF_CTR_OFFSET_SHIFT; attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */ attr.config2 = offset; /* kprobe_addr or probe_offset */ @@ -9340,85 +10779,1368 @@ static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name, pid < 0 ? -1 : pid /* pid */, pid == -1 ? 0 : -1 /* cpu */, -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC); - if (pfd < 0) { + return pfd >= 0 ? pfd : -errno; +} + +static int append_to_file(const char *file, const char *fmt, ...) +{ + int fd, n, err = 0; + va_list ap; + char buf[1024]; + + va_start(ap, fmt); + n = vsnprintf(buf, sizeof(buf), fmt, ap); + va_end(ap); + + if (n < 0 || n >= sizeof(buf)) + return -EINVAL; + + fd = open(file, O_WRONLY | O_APPEND | O_CLOEXEC, 0); + if (fd < 0) + return -errno; + + if (write(fd, buf, n) < 0) err = -errno; - pr_warn("%s perf_event_open() failed: %s\n", - uprobe ? "uprobe" : "kprobe", + + close(fd); + return err; +} + +#define DEBUGFS "/sys/kernel/debug/tracing" +#define TRACEFS "/sys/kernel/tracing" + +static bool use_debugfs(void) +{ + static int has_debugfs = -1; + + if (has_debugfs < 0) + has_debugfs = faccessat(AT_FDCWD, DEBUGFS, F_OK, AT_EACCESS) == 0; + + return has_debugfs == 1; +} + +static const char *tracefs_path(void) +{ + return use_debugfs() ? DEBUGFS : TRACEFS; +} + +static const char *tracefs_kprobe_events(void) +{ + return use_debugfs() ? DEBUGFS"/kprobe_events" : TRACEFS"/kprobe_events"; +} + +static const char *tracefs_uprobe_events(void) +{ + return use_debugfs() ? DEBUGFS"/uprobe_events" : TRACEFS"/uprobe_events"; +} + +static const char *tracefs_available_filter_functions(void) +{ + return use_debugfs() ? DEBUGFS"/available_filter_functions" + : TRACEFS"/available_filter_functions"; +} + +static const char *tracefs_available_filter_functions_addrs(void) +{ + return use_debugfs() ? DEBUGFS"/available_filter_functions_addrs" + : TRACEFS"/available_filter_functions_addrs"; +} + +static void gen_kprobe_legacy_event_name(char *buf, size_t buf_sz, + const char *kfunc_name, size_t offset) +{ + static int index = 0; + int i; + + snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx_%d", getpid(), kfunc_name, offset, + __sync_fetch_and_add(&index, 1)); + + /* sanitize binary_path in the probe name */ + for (i = 0; buf[i]; i++) { + if (!isalnum(buf[i])) + buf[i] = '_'; + } +} + +static int add_kprobe_event_legacy(const char *probe_name, bool retprobe, + const char *kfunc_name, size_t offset) +{ + return append_to_file(tracefs_kprobe_events(), "%c:%s/%s %s+0x%zx", + retprobe ? 'r' : 'p', + retprobe ? "kretprobes" : "kprobes", + probe_name, kfunc_name, offset); +} + +static int remove_kprobe_event_legacy(const char *probe_name, bool retprobe) +{ + return append_to_file(tracefs_kprobe_events(), "-:%s/%s", + retprobe ? "kretprobes" : "kprobes", probe_name); +} + +static int determine_kprobe_perf_type_legacy(const char *probe_name, bool retprobe) +{ + char file[256]; + + snprintf(file, sizeof(file), "%s/events/%s/%s/id", + tracefs_path(), retprobe ? "kretprobes" : "kprobes", probe_name); + + return parse_uint_from_file(file, "%d\n"); +} + +static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe, + const char *kfunc_name, size_t offset, int pid) +{ + const size_t attr_sz = sizeof(struct perf_event_attr); + struct perf_event_attr attr; + char errmsg[STRERR_BUFSIZE]; + int type, pfd, err; + + err = add_kprobe_event_legacy(probe_name, retprobe, kfunc_name, offset); + if (err < 0) { + pr_warn("failed to add legacy kprobe event for '%s+0x%zx': %s\n", + kfunc_name, offset, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); return err; } + type = determine_kprobe_perf_type_legacy(probe_name, retprobe); + if (type < 0) { + err = type; + pr_warn("failed to determine legacy kprobe event id for '%s+0x%zx': %s\n", + kfunc_name, offset, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto err_clean_legacy; + } + + memset(&attr, 0, attr_sz); + attr.size = attr_sz; + attr.config = type; + attr.type = PERF_TYPE_TRACEPOINT; + + pfd = syscall(__NR_perf_event_open, &attr, + pid < 0 ? -1 : pid, /* pid */ + pid == -1 ? 0 : -1, /* cpu */ + -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC); + if (pfd < 0) { + err = -errno; + pr_warn("legacy kprobe perf_event_open() failed: %s\n", + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto err_clean_legacy; + } return pfd; + +err_clean_legacy: + /* Clear the newly added legacy kprobe_event */ + remove_kprobe_event_legacy(probe_name, retprobe); + return err; } -struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog, - bool retprobe, - const char *func_name) +static const char *arch_specific_syscall_pfx(void) +{ +#if defined(__x86_64__) + return "x64"; +#elif defined(__i386__) + return "ia32"; +#elif defined(__s390x__) + return "s390x"; +#elif defined(__s390__) + return "s390"; +#elif defined(__arm__) + return "arm"; +#elif defined(__aarch64__) + return "arm64"; +#elif defined(__mips__) + return "mips"; +#elif defined(__riscv) + return "riscv"; +#elif defined(__powerpc__) + return "powerpc"; +#elif defined(__powerpc64__) + return "powerpc64"; +#else + return NULL; +#endif +} + +int probe_kern_syscall_wrapper(int token_fd) { + char syscall_name[64]; + const char *ksys_pfx; + + ksys_pfx = arch_specific_syscall_pfx(); + if (!ksys_pfx) + return 0; + + snprintf(syscall_name, sizeof(syscall_name), "__%s_sys_bpf", ksys_pfx); + + if (determine_kprobe_perf_type() >= 0) { + int pfd; + + pfd = perf_event_open_probe(false, false, syscall_name, 0, getpid(), 0); + if (pfd >= 0) + close(pfd); + + return pfd >= 0 ? 1 : 0; + } else { /* legacy mode */ + char probe_name[128]; + + gen_kprobe_legacy_event_name(probe_name, sizeof(probe_name), syscall_name, 0); + if (add_kprobe_event_legacy(probe_name, false, syscall_name, 0) < 0) + return 0; + + (void)remove_kprobe_event_legacy(probe_name, false); + return 1; + } +} + +struct bpf_link * +bpf_program__attach_kprobe_opts(const struct bpf_program *prog, + const char *func_name, + const struct bpf_kprobe_opts *opts) +{ + DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts); + enum probe_attach_mode attach_mode; char errmsg[STRERR_BUFSIZE]; + char *legacy_probe = NULL; struct bpf_link *link; + size_t offset; + bool retprobe, legacy; int pfd, err; - pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name, - 0 /* offset */, -1 /* pid */); + if (!OPTS_VALID(opts, bpf_kprobe_opts)) + return libbpf_err_ptr(-EINVAL); + + attach_mode = OPTS_GET(opts, attach_mode, PROBE_ATTACH_MODE_DEFAULT); + retprobe = OPTS_GET(opts, retprobe, false); + offset = OPTS_GET(opts, offset, 0); + pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); + + legacy = determine_kprobe_perf_type() < 0; + switch (attach_mode) { + case PROBE_ATTACH_MODE_LEGACY: + legacy = true; + pe_opts.force_ioctl_attach = true; + break; + case PROBE_ATTACH_MODE_PERF: + if (legacy) + return libbpf_err_ptr(-ENOTSUP); + pe_opts.force_ioctl_attach = true; + break; + case PROBE_ATTACH_MODE_LINK: + if (legacy || !kernel_supports(prog->obj, FEAT_PERF_LINK)) + return libbpf_err_ptr(-ENOTSUP); + break; + case PROBE_ATTACH_MODE_DEFAULT: + break; + default: + return libbpf_err_ptr(-EINVAL); + } + + if (!legacy) { + pfd = perf_event_open_probe(false /* uprobe */, retprobe, + func_name, offset, + -1 /* pid */, 0 /* ref_ctr_off */); + } else { + char probe_name[256]; + + gen_kprobe_legacy_event_name(probe_name, sizeof(probe_name), + func_name, offset); + + legacy_probe = strdup(probe_name); + if (!legacy_probe) + return libbpf_err_ptr(-ENOMEM); + + pfd = perf_event_kprobe_open_legacy(legacy_probe, retprobe, func_name, + offset, -1 /* pid */); + } if (pfd < 0) { - pr_warn("prog '%s': failed to create %s '%s' perf event: %s\n", - prog->name, retprobe ? "kretprobe" : "kprobe", func_name, - libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); - return ERR_PTR(pfd); + err = -errno; + pr_warn("prog '%s': failed to create %s '%s+0x%zx' perf event: %s\n", + prog->name, retprobe ? "kretprobe" : "kprobe", + func_name, offset, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto err_out; } - link = bpf_program__attach_perf_event(prog, pfd); - if (IS_ERR(link)) { + link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts); + err = libbpf_get_error(link); + if (err) { close(pfd); - err = PTR_ERR(link); - pr_warn("prog '%s': failed to attach to %s '%s': %s\n", - prog->name, retprobe ? "kretprobe" : "kprobe", func_name, + pr_warn("prog '%s': failed to attach to %s '%s+0x%zx': %s\n", + prog->name, retprobe ? "kretprobe" : "kprobe", + func_name, offset, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); - return link; + goto err_clean_legacy; + } + if (legacy) { + struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); + + perf_link->legacy_probe_name = legacy_probe; + perf_link->legacy_is_kprobe = true; + perf_link->legacy_is_retprobe = retprobe; } + return link; + +err_clean_legacy: + if (legacy) + remove_kprobe_event_legacy(legacy_probe, retprobe); +err_out: + free(legacy_probe); + return libbpf_err_ptr(err); } -static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec, - struct bpf_program *prog) +struct bpf_link *bpf_program__attach_kprobe(const struct bpf_program *prog, + bool retprobe, + const char *func_name) { - const char *func_name; + DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts, + .retprobe = retprobe, + ); + + return bpf_program__attach_kprobe_opts(prog, func_name, &opts); +} + +struct bpf_link *bpf_program__attach_ksyscall(const struct bpf_program *prog, + const char *syscall_name, + const struct bpf_ksyscall_opts *opts) +{ + LIBBPF_OPTS(bpf_kprobe_opts, kprobe_opts); + char func_name[128]; + + if (!OPTS_VALID(opts, bpf_ksyscall_opts)) + return libbpf_err_ptr(-EINVAL); + + if (kernel_supports(prog->obj, FEAT_SYSCALL_WRAPPER)) { + /* arch_specific_syscall_pfx() should never return NULL here + * because it is guarded by kernel_supports(). However, since + * compiler does not know that we have an explicit conditional + * as well. + */ + snprintf(func_name, sizeof(func_name), "__%s_sys_%s", + arch_specific_syscall_pfx() ? : "", syscall_name); + } else { + snprintf(func_name, sizeof(func_name), "__se_sys_%s", syscall_name); + } + + kprobe_opts.retprobe = OPTS_GET(opts, retprobe, false); + kprobe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); + + return bpf_program__attach_kprobe_opts(prog, func_name, &kprobe_opts); +} + +/* Adapted from perf/util/string.c */ +bool glob_match(const char *str, const char *pat) +{ + while (*str && *pat && *pat != '*') { + if (*pat == '?') { /* Matches any single character */ + str++; + pat++; + continue; + } + if (*str != *pat) + return false; + str++; + pat++; + } + /* Check wild card */ + if (*pat == '*') { + while (*pat == '*') + pat++; + if (!*pat) /* Tail wild card matches all */ + return true; + while (*str) + if (glob_match(str++, pat)) + return true; + } + return !*str && !*pat; +} + +struct kprobe_multi_resolve { + const char *pattern; + unsigned long *addrs; + size_t cap; + size_t cnt; +}; + +struct avail_kallsyms_data { + char **syms; + size_t cnt; + struct kprobe_multi_resolve *res; +}; + +static int avail_func_cmp(const void *a, const void *b) +{ + return strcmp(*(const char **)a, *(const char **)b); +} + +static int avail_kallsyms_cb(unsigned long long sym_addr, char sym_type, + const char *sym_name, void *ctx) +{ + struct avail_kallsyms_data *data = ctx; + struct kprobe_multi_resolve *res = data->res; + int err; + + if (!bsearch(&sym_name, data->syms, data->cnt, sizeof(*data->syms), avail_func_cmp)) + return 0; + + err = libbpf_ensure_mem((void **)&res->addrs, &res->cap, sizeof(*res->addrs), res->cnt + 1); + if (err) + return err; + + res->addrs[res->cnt++] = (unsigned long)sym_addr; + return 0; +} + +static int libbpf_available_kallsyms_parse(struct kprobe_multi_resolve *res) +{ + const char *available_functions_file = tracefs_available_filter_functions(); + struct avail_kallsyms_data data; + char sym_name[500]; + FILE *f; + int err = 0, ret, i; + char **syms = NULL; + size_t cap = 0, cnt = 0; + + f = fopen(available_functions_file, "re"); + if (!f) { + err = -errno; + pr_warn("failed to open %s: %d\n", available_functions_file, err); + return err; + } + + while (true) { + char *name; + + ret = fscanf(f, "%499s%*[^\n]\n", sym_name); + if (ret == EOF && feof(f)) + break; + + if (ret != 1) { + pr_warn("failed to parse available_filter_functions entry: %d\n", ret); + err = -EINVAL; + goto cleanup; + } + + if (!glob_match(sym_name, res->pattern)) + continue; + + err = libbpf_ensure_mem((void **)&syms, &cap, sizeof(*syms), cnt + 1); + if (err) + goto cleanup; + + name = strdup(sym_name); + if (!name) { + err = -errno; + goto cleanup; + } + + syms[cnt++] = name; + } + + /* no entries found, bail out */ + if (cnt == 0) { + err = -ENOENT; + goto cleanup; + } + + /* sort available functions */ + qsort(syms, cnt, sizeof(*syms), avail_func_cmp); + + data.syms = syms; + data.res = res; + data.cnt = cnt; + libbpf_kallsyms_parse(avail_kallsyms_cb, &data); + + if (res->cnt == 0) + err = -ENOENT; + +cleanup: + for (i = 0; i < cnt; i++) + free((char *)syms[i]); + free(syms); + + fclose(f); + return err; +} + +static bool has_available_filter_functions_addrs(void) +{ + return access(tracefs_available_filter_functions_addrs(), R_OK) != -1; +} + +static int libbpf_available_kprobes_parse(struct kprobe_multi_resolve *res) +{ + const char *available_path = tracefs_available_filter_functions_addrs(); + char sym_name[500]; + FILE *f; + int ret, err = 0; + unsigned long long sym_addr; + + f = fopen(available_path, "re"); + if (!f) { + err = -errno; + pr_warn("failed to open %s: %d\n", available_path, err); + return err; + } + + while (true) { + ret = fscanf(f, "%llx %499s%*[^\n]\n", &sym_addr, sym_name); + if (ret == EOF && feof(f)) + break; + + if (ret != 2) { + pr_warn("failed to parse available_filter_functions_addrs entry: %d\n", + ret); + err = -EINVAL; + goto cleanup; + } + + if (!glob_match(sym_name, res->pattern)) + continue; + + err = libbpf_ensure_mem((void **)&res->addrs, &res->cap, + sizeof(*res->addrs), res->cnt + 1); + if (err) + goto cleanup; + + res->addrs[res->cnt++] = (unsigned long)sym_addr; + } + + if (res->cnt == 0) + err = -ENOENT; + +cleanup: + fclose(f); + return err; +} + +struct bpf_link * +bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog, + const char *pattern, + const struct bpf_kprobe_multi_opts *opts) +{ + LIBBPF_OPTS(bpf_link_create_opts, lopts); + struct kprobe_multi_resolve res = { + .pattern = pattern, + }; + struct bpf_link *link = NULL; + char errmsg[STRERR_BUFSIZE]; + const unsigned long *addrs; + int err, link_fd, prog_fd; + const __u64 *cookies; + const char **syms; bool retprobe; + size_t cnt; + + if (!OPTS_VALID(opts, bpf_kprobe_multi_opts)) + return libbpf_err_ptr(-EINVAL); + + syms = OPTS_GET(opts, syms, false); + addrs = OPTS_GET(opts, addrs, false); + cnt = OPTS_GET(opts, cnt, false); + cookies = OPTS_GET(opts, cookies, false); + + if (!pattern && !addrs && !syms) + return libbpf_err_ptr(-EINVAL); + if (pattern && (addrs || syms || cookies || cnt)) + return libbpf_err_ptr(-EINVAL); + if (!pattern && !cnt) + return libbpf_err_ptr(-EINVAL); + if (addrs && syms) + return libbpf_err_ptr(-EINVAL); + + if (pattern) { + if (has_available_filter_functions_addrs()) + err = libbpf_available_kprobes_parse(&res); + else + err = libbpf_available_kallsyms_parse(&res); + if (err) + goto error; + addrs = res.addrs; + cnt = res.cnt; + } + + retprobe = OPTS_GET(opts, retprobe, false); + + lopts.kprobe_multi.syms = syms; + lopts.kprobe_multi.addrs = addrs; + lopts.kprobe_multi.cookies = cookies; + lopts.kprobe_multi.cnt = cnt; + lopts.kprobe_multi.flags = retprobe ? BPF_F_KPROBE_MULTI_RETURN : 0; + + link = calloc(1, sizeof(*link)); + if (!link) { + err = -ENOMEM; + goto error; + } + link->detach = &bpf_link__detach_fd; - func_name = prog->sec_name + sec->len; - retprobe = strcmp(sec->sec, "kretprobe/") == 0; + prog_fd = bpf_program__fd(prog); + link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_KPROBE_MULTI, &lopts); + if (link_fd < 0) { + err = -errno; + pr_warn("prog '%s': failed to attach: %s\n", + prog->name, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto error; + } + link->fd = link_fd; + free(res.addrs); + return link; - return bpf_program__attach_kprobe(prog, retprobe, func_name); +error: + free(link); + free(res.addrs); + return libbpf_err_ptr(err); } -struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog, - bool retprobe, pid_t pid, - const char *binary_path, - size_t func_offset) +static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts); + unsigned long offset = 0; + const char *func_name; + char *func; + int n; + + *link = NULL; + + /* no auto-attach for SEC("kprobe") and SEC("kretprobe") */ + if (strcmp(prog->sec_name, "kprobe") == 0 || strcmp(prog->sec_name, "kretprobe") == 0) + return 0; + + opts.retprobe = str_has_pfx(prog->sec_name, "kretprobe/"); + if (opts.retprobe) + func_name = prog->sec_name + sizeof("kretprobe/") - 1; + else + func_name = prog->sec_name + sizeof("kprobe/") - 1; + + n = sscanf(func_name, "%m[a-zA-Z0-9_.]+%li", &func, &offset); + if (n < 1) { + pr_warn("kprobe name is invalid: %s\n", func_name); + return -EINVAL; + } + if (opts.retprobe && offset != 0) { + free(func); + pr_warn("kretprobes do not support offset specification\n"); + return -EINVAL; + } + + opts.offset = offset; + *link = bpf_program__attach_kprobe_opts(prog, func, &opts); + free(func); + return libbpf_get_error(*link); +} + +static int attach_ksyscall(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + LIBBPF_OPTS(bpf_ksyscall_opts, opts); + const char *syscall_name; + + *link = NULL; + + /* no auto-attach for SEC("ksyscall") and SEC("kretsyscall") */ + if (strcmp(prog->sec_name, "ksyscall") == 0 || strcmp(prog->sec_name, "kretsyscall") == 0) + return 0; + + opts.retprobe = str_has_pfx(prog->sec_name, "kretsyscall/"); + if (opts.retprobe) + syscall_name = prog->sec_name + sizeof("kretsyscall/") - 1; + else + syscall_name = prog->sec_name + sizeof("ksyscall/") - 1; + + *link = bpf_program__attach_ksyscall(prog, syscall_name, &opts); + return *link ? 0 : -errno; +} + +static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + LIBBPF_OPTS(bpf_kprobe_multi_opts, opts); + const char *spec; + char *pattern; + int n; + + *link = NULL; + + /* no auto-attach for SEC("kprobe.multi") and SEC("kretprobe.multi") */ + if (strcmp(prog->sec_name, "kprobe.multi") == 0 || + strcmp(prog->sec_name, "kretprobe.multi") == 0) + return 0; + + opts.retprobe = str_has_pfx(prog->sec_name, "kretprobe.multi/"); + if (opts.retprobe) + spec = prog->sec_name + sizeof("kretprobe.multi/") - 1; + else + spec = prog->sec_name + sizeof("kprobe.multi/") - 1; + + n = sscanf(spec, "%m[a-zA-Z0-9_.*?]", &pattern); + if (n < 1) { + pr_warn("kprobe multi pattern is invalid: %s\n", pattern); + return -EINVAL; + } + + *link = bpf_program__attach_kprobe_multi_opts(prog, pattern, &opts); + free(pattern); + return libbpf_get_error(*link); +} + +static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link) { + char *probe_type = NULL, *binary_path = NULL, *func_name = NULL; + LIBBPF_OPTS(bpf_uprobe_multi_opts, opts); + int n, ret = -EINVAL; + + *link = NULL; + + n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%m[^\n]", + &probe_type, &binary_path, &func_name); + switch (n) { + case 1: + /* handle SEC("u[ret]probe") - format is valid, but auto-attach is impossible. */ + ret = 0; + break; + case 3: + opts.retprobe = strcmp(probe_type, "uretprobe.multi") == 0; + *link = bpf_program__attach_uprobe_multi(prog, -1, binary_path, func_name, &opts); + ret = libbpf_get_error(*link); + break; + default: + pr_warn("prog '%s': invalid format of section definition '%s'\n", prog->name, + prog->sec_name); + break; + } + free(probe_type); + free(binary_path); + free(func_name); + return ret; +} + +static void gen_uprobe_legacy_event_name(char *buf, size_t buf_sz, + const char *binary_path, uint64_t offset) +{ + int i; + + snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx", getpid(), binary_path, (size_t)offset); + + /* sanitize binary_path in the probe name */ + for (i = 0; buf[i]; i++) { + if (!isalnum(buf[i])) + buf[i] = '_'; + } +} + +static inline int add_uprobe_event_legacy(const char *probe_name, bool retprobe, + const char *binary_path, size_t offset) +{ + return append_to_file(tracefs_uprobe_events(), "%c:%s/%s %s:0x%zx", + retprobe ? 'r' : 'p', + retprobe ? "uretprobes" : "uprobes", + probe_name, binary_path, offset); +} + +static inline int remove_uprobe_event_legacy(const char *probe_name, bool retprobe) +{ + return append_to_file(tracefs_uprobe_events(), "-:%s/%s", + retprobe ? "uretprobes" : "uprobes", probe_name); +} + +static int determine_uprobe_perf_type_legacy(const char *probe_name, bool retprobe) +{ + char file[512]; + + snprintf(file, sizeof(file), "%s/events/%s/%s/id", + tracefs_path(), retprobe ? "uretprobes" : "uprobes", probe_name); + + return parse_uint_from_file(file, "%d\n"); +} + +static int perf_event_uprobe_open_legacy(const char *probe_name, bool retprobe, + const char *binary_path, size_t offset, int pid) +{ + const size_t attr_sz = sizeof(struct perf_event_attr); + struct perf_event_attr attr; + int type, pfd, err; + + err = add_uprobe_event_legacy(probe_name, retprobe, binary_path, offset); + if (err < 0) { + pr_warn("failed to add legacy uprobe event for %s:0x%zx: %d\n", + binary_path, (size_t)offset, err); + return err; + } + type = determine_uprobe_perf_type_legacy(probe_name, retprobe); + if (type < 0) { + err = type; + pr_warn("failed to determine legacy uprobe event id for %s:0x%zx: %d\n", + binary_path, offset, err); + goto err_clean_legacy; + } + + memset(&attr, 0, attr_sz); + attr.size = attr_sz; + attr.config = type; + attr.type = PERF_TYPE_TRACEPOINT; + + pfd = syscall(__NR_perf_event_open, &attr, + pid < 0 ? -1 : pid, /* pid */ + pid == -1 ? 0 : -1, /* cpu */ + -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC); + if (pfd < 0) { + err = -errno; + pr_warn("legacy uprobe perf_event_open() failed: %d\n", err); + goto err_clean_legacy; + } + return pfd; + +err_clean_legacy: + /* Clear the newly added legacy uprobe_event */ + remove_uprobe_event_legacy(probe_name, retprobe); + return err; +} + +/* Find offset of function name in archive specified by path. Currently + * supported are .zip files that do not compress their contents, as used on + * Android in the form of APKs, for example. "file_name" is the name of the ELF + * file inside the archive. "func_name" matches symbol name or name@@LIB for + * library functions. + * + * An overview of the APK format specifically provided here: + * https://en.wikipedia.org/w/index.php?title=Apk_(file_format)&oldid=1139099120#Package_contents + */ +static long elf_find_func_offset_from_archive(const char *archive_path, const char *file_name, + const char *func_name) +{ + struct zip_archive *archive; + struct zip_entry entry; + long ret; + Elf *elf; + + archive = zip_archive_open(archive_path); + if (IS_ERR(archive)) { + ret = PTR_ERR(archive); + pr_warn("zip: failed to open %s: %ld\n", archive_path, ret); + return ret; + } + + ret = zip_archive_find_entry(archive, file_name, &entry); + if (ret) { + pr_warn("zip: could not find archive member %s in %s: %ld\n", file_name, + archive_path, ret); + goto out; + } + pr_debug("zip: found entry for %s in %s at 0x%lx\n", file_name, archive_path, + (unsigned long)entry.data_offset); + + if (entry.compression) { + pr_warn("zip: entry %s of %s is compressed and cannot be handled\n", file_name, + archive_path); + ret = -LIBBPF_ERRNO__FORMAT; + goto out; + } + + elf = elf_memory((void *)entry.data, entry.data_length); + if (!elf) { + pr_warn("elf: could not read elf file %s from %s: %s\n", file_name, archive_path, + elf_errmsg(-1)); + ret = -LIBBPF_ERRNO__LIBELF; + goto out; + } + + ret = elf_find_func_offset(elf, file_name, func_name); + if (ret > 0) { + pr_debug("elf: symbol address match for %s of %s in %s: 0x%x + 0x%lx = 0x%lx\n", + func_name, file_name, archive_path, entry.data_offset, ret, + ret + entry.data_offset); + ret += entry.data_offset; + } + elf_end(elf); + +out: + zip_archive_close(archive); + return ret; +} + +static const char *arch_specific_lib_paths(void) +{ + /* + * Based on https://packages.debian.org/sid/libc6. + * + * Assume that the traced program is built for the same architecture + * as libbpf, which should cover the vast majority of cases. + */ +#if defined(__x86_64__) + return "/lib/x86_64-linux-gnu"; +#elif defined(__i386__) + return "/lib/i386-linux-gnu"; +#elif defined(__s390x__) + return "/lib/s390x-linux-gnu"; +#elif defined(__s390__) + return "/lib/s390-linux-gnu"; +#elif defined(__arm__) && defined(__SOFTFP__) + return "/lib/arm-linux-gnueabi"; +#elif defined(__arm__) && !defined(__SOFTFP__) + return "/lib/arm-linux-gnueabihf"; +#elif defined(__aarch64__) + return "/lib/aarch64-linux-gnu"; +#elif defined(__mips__) && defined(__MIPSEL__) && _MIPS_SZLONG == 64 + return "/lib/mips64el-linux-gnuabi64"; +#elif defined(__mips__) && defined(__MIPSEL__) && _MIPS_SZLONG == 32 + return "/lib/mipsel-linux-gnu"; +#elif defined(__powerpc64__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + return "/lib/powerpc64le-linux-gnu"; +#elif defined(__sparc__) && defined(__arch64__) + return "/lib/sparc64-linux-gnu"; +#elif defined(__riscv) && __riscv_xlen == 64 + return "/lib/riscv64-linux-gnu"; +#else + return NULL; +#endif +} + +/* Get full path to program/shared library. */ +static int resolve_full_path(const char *file, char *result, size_t result_sz) +{ + const char *search_paths[3] = {}; + int i, perm; + + if (str_has_sfx(file, ".so") || strstr(file, ".so.")) { + search_paths[0] = getenv("LD_LIBRARY_PATH"); + search_paths[1] = "/usr/lib64:/usr/lib"; + search_paths[2] = arch_specific_lib_paths(); + perm = R_OK; + } else { + search_paths[0] = getenv("PATH"); + search_paths[1] = "/usr/bin:/usr/sbin"; + perm = R_OK | X_OK; + } + + for (i = 0; i < ARRAY_SIZE(search_paths); i++) { + const char *s; + + if (!search_paths[i]) + continue; + for (s = search_paths[i]; s != NULL; s = strchr(s, ':')) { + char *next_path; + int seg_len; + + if (s[0] == ':') + s++; + next_path = strchr(s, ':'); + seg_len = next_path ? next_path - s : strlen(s); + if (!seg_len) + continue; + snprintf(result, result_sz, "%.*s/%s", seg_len, s, file); + /* ensure it has required permissions */ + if (faccessat(AT_FDCWD, result, perm, AT_EACCESS) < 0) + continue; + pr_debug("resolved '%s' to '%s'\n", file, result); + return 0; + } + } + return -ENOENT; +} + +struct bpf_link * +bpf_program__attach_uprobe_multi(const struct bpf_program *prog, + pid_t pid, + const char *path, + const char *func_pattern, + const struct bpf_uprobe_multi_opts *opts) +{ + const unsigned long *ref_ctr_offsets = NULL, *offsets = NULL; + LIBBPF_OPTS(bpf_link_create_opts, lopts); + unsigned long *resolved_offsets = NULL; + int err = 0, link_fd, prog_fd; + struct bpf_link *link = NULL; char errmsg[STRERR_BUFSIZE]; + char full_path[PATH_MAX]; + const __u64 *cookies; + const char **syms; + size_t cnt; + + if (!OPTS_VALID(opts, bpf_uprobe_multi_opts)) + return libbpf_err_ptr(-EINVAL); + + syms = OPTS_GET(opts, syms, NULL); + offsets = OPTS_GET(opts, offsets, NULL); + ref_ctr_offsets = OPTS_GET(opts, ref_ctr_offsets, NULL); + cookies = OPTS_GET(opts, cookies, NULL); + cnt = OPTS_GET(opts, cnt, 0); + + /* + * User can specify 2 mutually exclusive set of inputs: + * + * 1) use only path/func_pattern/pid arguments + * + * 2) use path/pid with allowed combinations of: + * syms/offsets/ref_ctr_offsets/cookies/cnt + * + * - syms and offsets are mutually exclusive + * - ref_ctr_offsets and cookies are optional + * + * Any other usage results in error. + */ + + if (!path) + return libbpf_err_ptr(-EINVAL); + if (!func_pattern && cnt == 0) + return libbpf_err_ptr(-EINVAL); + + if (func_pattern) { + if (syms || offsets || ref_ctr_offsets || cookies || cnt) + return libbpf_err_ptr(-EINVAL); + } else { + if (!!syms == !!offsets) + return libbpf_err_ptr(-EINVAL); + } + + if (func_pattern) { + if (!strchr(path, '/')) { + err = resolve_full_path(path, full_path, sizeof(full_path)); + if (err) { + pr_warn("prog '%s': failed to resolve full path for '%s': %d\n", + prog->name, path, err); + return libbpf_err_ptr(err); + } + path = full_path; + } + + err = elf_resolve_pattern_offsets(path, func_pattern, + &resolved_offsets, &cnt); + if (err < 0) + return libbpf_err_ptr(err); + offsets = resolved_offsets; + } else if (syms) { + err = elf_resolve_syms_offsets(path, cnt, syms, &resolved_offsets, STT_FUNC); + if (err < 0) + return libbpf_err_ptr(err); + offsets = resolved_offsets; + } + + lopts.uprobe_multi.path = path; + lopts.uprobe_multi.offsets = offsets; + lopts.uprobe_multi.ref_ctr_offsets = ref_ctr_offsets; + lopts.uprobe_multi.cookies = cookies; + lopts.uprobe_multi.cnt = cnt; + lopts.uprobe_multi.flags = OPTS_GET(opts, retprobe, false) ? BPF_F_UPROBE_MULTI_RETURN : 0; + + if (pid == 0) + pid = getpid(); + if (pid > 0) + lopts.uprobe_multi.pid = pid; + + link = calloc(1, sizeof(*link)); + if (!link) { + err = -ENOMEM; + goto error; + } + link->detach = &bpf_link__detach_fd; + + prog_fd = bpf_program__fd(prog); + link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &lopts); + if (link_fd < 0) { + err = -errno; + pr_warn("prog '%s': failed to attach multi-uprobe: %s\n", + prog->name, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto error; + } + link->fd = link_fd; + free(resolved_offsets); + return link; + +error: + free(resolved_offsets); + free(link); + return libbpf_err_ptr(err); +} + +LIBBPF_API struct bpf_link * +bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid, + const char *binary_path, size_t func_offset, + const struct bpf_uprobe_opts *opts) +{ + const char *archive_path = NULL, *archive_sep = NULL; + char errmsg[STRERR_BUFSIZE], *legacy_probe = NULL; + DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts); + enum probe_attach_mode attach_mode; + char full_path[PATH_MAX]; struct bpf_link *link; + size_t ref_ctr_off; int pfd, err; + bool retprobe, legacy; + const char *func_name; + + if (!OPTS_VALID(opts, bpf_uprobe_opts)) + return libbpf_err_ptr(-EINVAL); + + attach_mode = OPTS_GET(opts, attach_mode, PROBE_ATTACH_MODE_DEFAULT); + retprobe = OPTS_GET(opts, retprobe, false); + ref_ctr_off = OPTS_GET(opts, ref_ctr_offset, 0); + pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); + + if (!binary_path) + return libbpf_err_ptr(-EINVAL); + + /* Check if "binary_path" refers to an archive. */ + archive_sep = strstr(binary_path, "!/"); + if (archive_sep) { + full_path[0] = '\0'; + libbpf_strlcpy(full_path, binary_path, + min(sizeof(full_path), (size_t)(archive_sep - binary_path + 1))); + archive_path = full_path; + binary_path = archive_sep + 2; + } else if (!strchr(binary_path, '/')) { + err = resolve_full_path(binary_path, full_path, sizeof(full_path)); + if (err) { + pr_warn("prog '%s': failed to resolve full path for '%s': %d\n", + prog->name, binary_path, err); + return libbpf_err_ptr(err); + } + binary_path = full_path; + } + func_name = OPTS_GET(opts, func_name, NULL); + if (func_name) { + long sym_off; + + if (archive_path) { + sym_off = elf_find_func_offset_from_archive(archive_path, binary_path, + func_name); + binary_path = archive_path; + } else { + sym_off = elf_find_func_offset_from_file(binary_path, func_name); + } + if (sym_off < 0) + return libbpf_err_ptr(sym_off); + func_offset += sym_off; + } - pfd = perf_event_open_probe(true /* uprobe */, retprobe, - binary_path, func_offset, pid); + legacy = determine_uprobe_perf_type() < 0; + switch (attach_mode) { + case PROBE_ATTACH_MODE_LEGACY: + legacy = true; + pe_opts.force_ioctl_attach = true; + break; + case PROBE_ATTACH_MODE_PERF: + if (legacy) + return libbpf_err_ptr(-ENOTSUP); + pe_opts.force_ioctl_attach = true; + break; + case PROBE_ATTACH_MODE_LINK: + if (legacy || !kernel_supports(prog->obj, FEAT_PERF_LINK)) + return libbpf_err_ptr(-ENOTSUP); + break; + case PROBE_ATTACH_MODE_DEFAULT: + break; + default: + return libbpf_err_ptr(-EINVAL); + } + + if (!legacy) { + pfd = perf_event_open_probe(true /* uprobe */, retprobe, binary_path, + func_offset, pid, ref_ctr_off); + } else { + char probe_name[PATH_MAX + 64]; + + if (ref_ctr_off) + return libbpf_err_ptr(-EINVAL); + + gen_uprobe_legacy_event_name(probe_name, sizeof(probe_name), + binary_path, func_offset); + + legacy_probe = strdup(probe_name); + if (!legacy_probe) + return libbpf_err_ptr(-ENOMEM); + + pfd = perf_event_uprobe_open_legacy(legacy_probe, retprobe, + binary_path, func_offset, pid); + } if (pfd < 0) { + err = -errno; pr_warn("prog '%s': failed to create %s '%s:0x%zx' perf event: %s\n", prog->name, retprobe ? "uretprobe" : "uprobe", binary_path, func_offset, - libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); - return ERR_PTR(pfd); + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto err_out; } - link = bpf_program__attach_perf_event(prog, pfd); - if (IS_ERR(link)) { + + link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts); + err = libbpf_get_error(link); + if (err) { close(pfd); - err = PTR_ERR(link); pr_warn("prog '%s': failed to attach to %s '%s:0x%zx': %s\n", prog->name, retprobe ? "uretprobe" : "uprobe", binary_path, func_offset, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); - return link; + goto err_clean_legacy; + } + if (legacy) { + struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); + + perf_link->legacy_probe_name = legacy_probe; + perf_link->legacy_is_kprobe = false; + perf_link->legacy_is_retprobe = retprobe; } return link; + +err_clean_legacy: + if (legacy) + remove_uprobe_event_legacy(legacy_probe, retprobe); +err_out: + free(legacy_probe); + return libbpf_err_ptr(err); +} + +/* Format of u[ret]probe section definition supporting auto-attach: + * u[ret]probe/binary:function[+offset] + * + * binary can be an absolute/relative path or a filename; the latter is resolved to a + * full binary path via bpf_program__attach_uprobe_opts. + * + * Specifying uprobe+ ensures we carry out strict matching; either "uprobe" must be + * specified (and auto-attach is not possible) or the above format is specified for + * auto-attach. + */ +static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, opts); + char *probe_type = NULL, *binary_path = NULL, *func_name = NULL, *func_off; + int n, c, ret = -EINVAL; + long offset = 0; + + *link = NULL; + + n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%m[^\n]", + &probe_type, &binary_path, &func_name); + switch (n) { + case 1: + /* handle SEC("u[ret]probe") - format is valid, but auto-attach is impossible. */ + ret = 0; + break; + case 2: + pr_warn("prog '%s': section '%s' missing ':function[+offset]' specification\n", + prog->name, prog->sec_name); + break; + case 3: + /* check if user specifies `+offset`, if yes, this should be + * the last part of the string, make sure sscanf read to EOL + */ + func_off = strrchr(func_name, '+'); + if (func_off) { + n = sscanf(func_off, "+%li%n", &offset, &c); + if (n == 1 && *(func_off + c) == '\0') + func_off[0] = '\0'; + else + offset = 0; + } + opts.retprobe = strcmp(probe_type, "uretprobe") == 0 || + strcmp(probe_type, "uretprobe.s") == 0; + if (opts.retprobe && offset != 0) { + pr_warn("prog '%s': uretprobes do not support offset specification\n", + prog->name); + break; + } + opts.func_name = func_name; + *link = bpf_program__attach_uprobe_opts(prog, -1, binary_path, offset, &opts); + ret = libbpf_get_error(*link); + break; + default: + pr_warn("prog '%s': invalid format of section definition '%s'\n", prog->name, + prog->sec_name); + break; + } + free(probe_type); + free(binary_path); + free(func_name); + + return ret; +} + +struct bpf_link *bpf_program__attach_uprobe(const struct bpf_program *prog, + bool retprobe, pid_t pid, + const char *binary_path, + size_t func_offset) +{ + DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, opts, .retprobe = retprobe); + + return bpf_program__attach_uprobe_opts(prog, pid, binary_path, func_offset, &opts); +} + +struct bpf_link *bpf_program__attach_usdt(const struct bpf_program *prog, + pid_t pid, const char *binary_path, + const char *usdt_provider, const char *usdt_name, + const struct bpf_usdt_opts *opts) +{ + char resolved_path[512]; + struct bpf_object *obj = prog->obj; + struct bpf_link *link; + __u64 usdt_cookie; + int err; + + if (!OPTS_VALID(opts, bpf_uprobe_opts)) + return libbpf_err_ptr(-EINVAL); + + if (bpf_program__fd(prog) < 0) { + pr_warn("prog '%s': can't attach BPF program w/o FD (did you load it?)\n", + prog->name); + return libbpf_err_ptr(-EINVAL); + } + + if (!binary_path) + return libbpf_err_ptr(-EINVAL); + + if (!strchr(binary_path, '/')) { + err = resolve_full_path(binary_path, resolved_path, sizeof(resolved_path)); + if (err) { + pr_warn("prog '%s': failed to resolve full path for '%s': %d\n", + prog->name, binary_path, err); + return libbpf_err_ptr(err); + } + binary_path = resolved_path; + } + + /* USDT manager is instantiated lazily on first USDT attach. It will + * be destroyed together with BPF object in bpf_object__close(). + */ + if (IS_ERR(obj->usdt_man)) + return libbpf_ptr(obj->usdt_man); + if (!obj->usdt_man) { + obj->usdt_man = usdt_manager_new(obj); + if (IS_ERR(obj->usdt_man)) + return libbpf_ptr(obj->usdt_man); + } + + usdt_cookie = OPTS_GET(opts, usdt_cookie, 0); + link = usdt_manager_attach_usdt(obj->usdt_man, prog, pid, binary_path, + usdt_provider, usdt_name, usdt_cookie); + err = libbpf_get_error(link); + if (err) + return libbpf_err_ptr(err); + return link; +} + +static int attach_usdt(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + char *path = NULL, *provider = NULL, *name = NULL; + const char *sec_name; + int n, err; + + sec_name = bpf_program__section_name(prog); + if (strcmp(sec_name, "usdt") == 0) { + /* no auto-attach for just SEC("usdt") */ + *link = NULL; + return 0; + } + + n = sscanf(sec_name, "usdt/%m[^:]:%m[^:]:%m[^:]", &path, &provider, &name); + if (n != 3) { + pr_warn("invalid section '%s', expected SEC(\"usdt/<path>:<provider>:<name>\")\n", + sec_name); + err = -EINVAL; + } else { + *link = bpf_program__attach_usdt(prog, -1 /* any process */, path, + provider, name, NULL); + err = libbpf_get_error(*link); + } + free(path); + free(provider); + free(name); + return err; } static int determine_tracepoint_id(const char *tp_category, @@ -9427,9 +12149,8 @@ static int determine_tracepoint_id(const char *tp_category, char file[PATH_MAX]; int ret; - ret = snprintf(file, sizeof(file), - "/sys/kernel/debug/tracing/events/%s/%s/id", - tp_category, tp_name); + ret = snprintf(file, sizeof(file), "%s/events/%s/%s/id", + tracefs_path(), tp_category, tp_name); if (ret < 0) return -errno; if (ret >= sizeof(file)) { @@ -9443,7 +12164,8 @@ static int determine_tracepoint_id(const char *tp_category, static int perf_event_open_tracepoint(const char *tp_category, const char *tp_name) { - struct perf_event_attr attr = {}; + const size_t attr_sz = sizeof(struct perf_event_attr); + struct perf_event_attr attr; char errmsg[STRERR_BUFSIZE]; int tp_id, pfd, err; @@ -9455,8 +12177,9 @@ static int perf_event_open_tracepoint(const char *tp_category, return tp_id; } + memset(&attr, 0, attr_sz); attr.type = PERF_TYPE_TRACEPOINT; - attr.size = sizeof(attr); + attr.size = attr_sz; attr.config = tp_id; pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */, @@ -9471,60 +12194,80 @@ static int perf_event_open_tracepoint(const char *tp_category, return pfd; } -struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog, - const char *tp_category, - const char *tp_name) +struct bpf_link *bpf_program__attach_tracepoint_opts(const struct bpf_program *prog, + const char *tp_category, + const char *tp_name, + const struct bpf_tracepoint_opts *opts) { + DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts); char errmsg[STRERR_BUFSIZE]; struct bpf_link *link; int pfd, err; + if (!OPTS_VALID(opts, bpf_tracepoint_opts)) + return libbpf_err_ptr(-EINVAL); + + pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); + pfd = perf_event_open_tracepoint(tp_category, tp_name); if (pfd < 0) { pr_warn("prog '%s': failed to create tracepoint '%s/%s' perf event: %s\n", prog->name, tp_category, tp_name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); - return ERR_PTR(pfd); + return libbpf_err_ptr(pfd); } - link = bpf_program__attach_perf_event(prog, pfd); - if (IS_ERR(link)) { + link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts); + err = libbpf_get_error(link); + if (err) { close(pfd); - err = PTR_ERR(link); pr_warn("prog '%s': failed to attach to tracepoint '%s/%s': %s\n", prog->name, tp_category, tp_name, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); - return link; + return libbpf_err_ptr(err); } return link; } -static struct bpf_link *attach_tp(const struct bpf_sec_def *sec, - struct bpf_program *prog) +struct bpf_link *bpf_program__attach_tracepoint(const struct bpf_program *prog, + const char *tp_category, + const char *tp_name) +{ + return bpf_program__attach_tracepoint_opts(prog, tp_category, tp_name, NULL); +} + +static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link) { char *sec_name, *tp_cat, *tp_name; - struct bpf_link *link; + + *link = NULL; + + /* no auto-attach for SEC("tp") or SEC("tracepoint") */ + if (strcmp(prog->sec_name, "tp") == 0 || strcmp(prog->sec_name, "tracepoint") == 0) + return 0; sec_name = strdup(prog->sec_name); if (!sec_name) - return ERR_PTR(-ENOMEM); + return -ENOMEM; - /* extract "tp/<category>/<name>" */ - tp_cat = sec_name + sec->len; + /* extract "tp/<category>/<name>" or "tracepoint/<category>/<name>" */ + if (str_has_pfx(prog->sec_name, "tp/")) + tp_cat = sec_name + sizeof("tp/") - 1; + else + tp_cat = sec_name + sizeof("tracepoint/") - 1; tp_name = strchr(tp_cat, '/'); if (!tp_name) { - link = ERR_PTR(-EINVAL); - goto out; + free(sec_name); + return -EINVAL; } *tp_name = '\0'; tp_name++; - link = bpf_program__attach_tracepoint(prog, tp_cat, tp_name); -out: + *link = bpf_program__attach_tracepoint(prog, tp_cat, tp_name); free(sec_name); - return link; + return libbpf_get_error(*link); } -struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog, +struct bpf_link *bpf_program__attach_raw_tracepoint(const struct bpf_program *prog, const char *tp_name) { char errmsg[STRERR_BUFSIZE]; @@ -9534,12 +12277,12 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog, prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach before loaded\n", prog->name); - return ERR_PTR(-EINVAL); + return libbpf_err_ptr(-EINVAL); } link = calloc(1, sizeof(*link)); if (!link) - return ERR_PTR(-ENOMEM); + return libbpf_err_ptr(-ENOMEM); link->detach = &bpf_link__detach_fd; pfd = bpf_raw_tracepoint_open(tp_name, prog_fd); @@ -9548,84 +12291,123 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog, free(link); pr_warn("prog '%s': failed to attach to raw tracepoint '%s': %s\n", prog->name, tp_name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); - return ERR_PTR(pfd); + return libbpf_err_ptr(pfd); } link->fd = pfd; return link; } -static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec, - struct bpf_program *prog) +static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link) { - const char *tp_name = prog->sec_name + sec->len; + static const char *const prefixes[] = { + "raw_tp", + "raw_tracepoint", + "raw_tp.w", + "raw_tracepoint.w", + }; + size_t i; + const char *tp_name = NULL; + + *link = NULL; + + for (i = 0; i < ARRAY_SIZE(prefixes); i++) { + size_t pfx_len; + + if (!str_has_pfx(prog->sec_name, prefixes[i])) + continue; - return bpf_program__attach_raw_tracepoint(prog, tp_name); + pfx_len = strlen(prefixes[i]); + /* no auto-attach case of, e.g., SEC("raw_tp") */ + if (prog->sec_name[pfx_len] == '\0') + return 0; + + if (prog->sec_name[pfx_len] != '/') + continue; + + tp_name = prog->sec_name + pfx_len + 1; + break; + } + + if (!tp_name) { + pr_warn("prog '%s': invalid section name '%s'\n", + prog->name, prog->sec_name); + return -EINVAL; + } + + *link = bpf_program__attach_raw_tracepoint(prog, tp_name); + return libbpf_get_error(*link); } /* Common logic for all BPF program types that attach to a btf_id */ -static struct bpf_link *bpf_program__attach_btf_id(struct bpf_program *prog) +static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *prog, + const struct bpf_trace_opts *opts) { + LIBBPF_OPTS(bpf_link_create_opts, link_opts); char errmsg[STRERR_BUFSIZE]; struct bpf_link *link; int prog_fd, pfd; + if (!OPTS_VALID(opts, bpf_trace_opts)) + return libbpf_err_ptr(-EINVAL); + prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach before loaded\n", prog->name); - return ERR_PTR(-EINVAL); + return libbpf_err_ptr(-EINVAL); } link = calloc(1, sizeof(*link)); if (!link) - return ERR_PTR(-ENOMEM); + return libbpf_err_ptr(-ENOMEM); link->detach = &bpf_link__detach_fd; - pfd = bpf_raw_tracepoint_open(NULL, prog_fd); + /* libbpf is smart enough to redirect to BPF_RAW_TRACEPOINT_OPEN on old kernels */ + link_opts.tracing.cookie = OPTS_GET(opts, cookie, 0); + pfd = bpf_link_create(prog_fd, 0, bpf_program__expected_attach_type(prog), &link_opts); if (pfd < 0) { pfd = -errno; free(link); pr_warn("prog '%s': failed to attach: %s\n", prog->name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); - return ERR_PTR(pfd); + return libbpf_err_ptr(pfd); } link->fd = pfd; - return (struct bpf_link *)link; + return link; } -struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog) +struct bpf_link *bpf_program__attach_trace(const struct bpf_program *prog) { - return bpf_program__attach_btf_id(prog); + return bpf_program__attach_btf_id(prog, NULL); } -struct bpf_link *bpf_program__attach_lsm(struct bpf_program *prog) +struct bpf_link *bpf_program__attach_trace_opts(const struct bpf_program *prog, + const struct bpf_trace_opts *opts) { - return bpf_program__attach_btf_id(prog); + return bpf_program__attach_btf_id(prog, opts); } -static struct bpf_link *attach_trace(const struct bpf_sec_def *sec, - struct bpf_program *prog) +struct bpf_link *bpf_program__attach_lsm(const struct bpf_program *prog) { - return bpf_program__attach_trace(prog); + return bpf_program__attach_btf_id(prog, NULL); } -static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec, - struct bpf_program *prog) +static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link) { - return bpf_program__attach_lsm(prog); + *link = bpf_program__attach_trace(prog); + return libbpf_get_error(*link); } -static struct bpf_link *attach_iter(const struct bpf_sec_def *sec, - struct bpf_program *prog) +static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link) { - return bpf_program__attach_iter(prog, NULL); + *link = bpf_program__attach_lsm(prog); + return libbpf_get_error(*link); } static struct bpf_link * -bpf_program__attach_fd(struct bpf_program *prog, int target_fd, int btf_id, - const char *target_name) +bpf_program_attach_fd(const struct bpf_program *prog, + int target_fd, const char *target_name, + const struct bpf_link_create_opts *opts) { - DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts, - .target_btf_id = btf_id); enum bpf_attach_type attach_type; char errmsg[STRERR_BUFSIZE]; struct bpf_link *link; @@ -9634,47 +12416,116 @@ bpf_program__attach_fd(struct bpf_program *prog, int target_fd, int btf_id, prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach before loaded\n", prog->name); - return ERR_PTR(-EINVAL); + return libbpf_err_ptr(-EINVAL); } link = calloc(1, sizeof(*link)); if (!link) - return ERR_PTR(-ENOMEM); + return libbpf_err_ptr(-ENOMEM); link->detach = &bpf_link__detach_fd; - attach_type = bpf_program__get_expected_attach_type(prog); - link_fd = bpf_link_create(prog_fd, target_fd, attach_type, &opts); + attach_type = bpf_program__expected_attach_type(prog); + link_fd = bpf_link_create(prog_fd, target_fd, attach_type, opts); if (link_fd < 0) { link_fd = -errno; free(link); pr_warn("prog '%s': failed to attach to %s: %s\n", prog->name, target_name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); - return ERR_PTR(link_fd); + return libbpf_err_ptr(link_fd); } link->fd = link_fd; return link; } struct bpf_link * -bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd) +bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd) { - return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup"); + return bpf_program_attach_fd(prog, cgroup_fd, "cgroup", NULL); } struct bpf_link * -bpf_program__attach_netns(struct bpf_program *prog, int netns_fd) +bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd) +{ + return bpf_program_attach_fd(prog, netns_fd, "netns", NULL); +} + +struct bpf_link *bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex) { - return bpf_program__attach_fd(prog, netns_fd, 0, "netns"); + /* target_fd/target_ifindex use the same field in LINK_CREATE */ + return bpf_program_attach_fd(prog, ifindex, "xdp", NULL); } -struct bpf_link *bpf_program__attach_xdp(struct bpf_program *prog, int ifindex) +struct bpf_link * +bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex, + const struct bpf_tcx_opts *opts) { + LIBBPF_OPTS(bpf_link_create_opts, link_create_opts); + __u32 relative_id; + int relative_fd; + + if (!OPTS_VALID(opts, bpf_tcx_opts)) + return libbpf_err_ptr(-EINVAL); + + relative_id = OPTS_GET(opts, relative_id, 0); + relative_fd = OPTS_GET(opts, relative_fd, 0); + + /* validate we don't have unexpected combinations of non-zero fields */ + if (!ifindex) { + pr_warn("prog '%s': target netdevice ifindex cannot be zero\n", + prog->name); + return libbpf_err_ptr(-EINVAL); + } + if (relative_fd && relative_id) { + pr_warn("prog '%s': relative_fd and relative_id cannot be set at the same time\n", + prog->name); + return libbpf_err_ptr(-EINVAL); + } + + link_create_opts.tcx.expected_revision = OPTS_GET(opts, expected_revision, 0); + link_create_opts.tcx.relative_fd = relative_fd; + link_create_opts.tcx.relative_id = relative_id; + link_create_opts.flags = OPTS_GET(opts, flags, 0); + /* target_fd/target_ifindex use the same field in LINK_CREATE */ - return bpf_program__attach_fd(prog, ifindex, 0, "xdp"); + return bpf_program_attach_fd(prog, ifindex, "tcx", &link_create_opts); } -struct bpf_link *bpf_program__attach_freplace(struct bpf_program *prog, +struct bpf_link * +bpf_program__attach_netkit(const struct bpf_program *prog, int ifindex, + const struct bpf_netkit_opts *opts) +{ + LIBBPF_OPTS(bpf_link_create_opts, link_create_opts); + __u32 relative_id; + int relative_fd; + + if (!OPTS_VALID(opts, bpf_netkit_opts)) + return libbpf_err_ptr(-EINVAL); + + relative_id = OPTS_GET(opts, relative_id, 0); + relative_fd = OPTS_GET(opts, relative_fd, 0); + + /* validate we don't have unexpected combinations of non-zero fields */ + if (!ifindex) { + pr_warn("prog '%s': target netdevice ifindex cannot be zero\n", + prog->name); + return libbpf_err_ptr(-EINVAL); + } + if (relative_fd && relative_id) { + pr_warn("prog '%s': relative_fd and relative_id cannot be set at the same time\n", + prog->name); + return libbpf_err_ptr(-EINVAL); + } + + link_create_opts.netkit.expected_revision = OPTS_GET(opts, expected_revision, 0); + link_create_opts.netkit.relative_fd = relative_fd; + link_create_opts.netkit.relative_id = relative_id; + link_create_opts.flags = OPTS_GET(opts, flags, 0); + + return bpf_program_attach_fd(prog, ifindex, "netkit", &link_create_opts); +} + +struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog, int target_fd, const char *attach_func_name) { @@ -9683,21 +12534,26 @@ struct bpf_link *bpf_program__attach_freplace(struct bpf_program *prog, if (!!target_fd != !!attach_func_name) { pr_warn("prog '%s': supply none or both of target_fd and attach_func_name\n", prog->name); - return ERR_PTR(-EINVAL); + return libbpf_err_ptr(-EINVAL); } if (prog->type != BPF_PROG_TYPE_EXT) { pr_warn("prog '%s': only BPF_PROG_TYPE_EXT can attach as freplace", prog->name); - return ERR_PTR(-EINVAL); + return libbpf_err_ptr(-EINVAL); } if (target_fd) { + LIBBPF_OPTS(bpf_link_create_opts, target_opts); + btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd); if (btf_id < 0) - return ERR_PTR(btf_id); + return libbpf_err_ptr(btf_id); - return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace"); + target_opts.target_btf_id = btf_id; + + return bpf_program_attach_fd(prog, target_fd, "freplace", + &target_opts); } else { /* no target, so use raw_tracepoint_open for compatibility * with old kernels @@ -9707,7 +12563,7 @@ struct bpf_link *bpf_program__attach_freplace(struct bpf_program *prog, } struct bpf_link * -bpf_program__attach_iter(struct bpf_program *prog, +bpf_program__attach_iter(const struct bpf_program *prog, const struct bpf_iter_attach_opts *opts) { DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_create_opts); @@ -9717,7 +12573,7 @@ bpf_program__attach_iter(struct bpf_program *prog, __u32 target_fd = 0; if (!OPTS_VALID(opts, bpf_iter_attach_opts)) - return ERR_PTR(-EINVAL); + return libbpf_err_ptr(-EINVAL); link_create_opts.iter_info = OPTS_GET(opts, link_info, (void *)0); link_create_opts.iter_info_len = OPTS_GET(opts, link_info_len, 0); @@ -9725,12 +12581,12 @@ bpf_program__attach_iter(struct bpf_program *prog, prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach before loaded\n", prog->name); - return ERR_PTR(-EINVAL); + return libbpf_err_ptr(-EINVAL); } link = calloc(1, sizeof(*link)); if (!link) - return ERR_PTR(-ENOMEM); + return libbpf_err_ptr(-ENOMEM); link->detach = &bpf_link__detach_fd; link_fd = bpf_link_create(prog_fd, target_fd, BPF_TRACE_ITER, @@ -9740,78 +12596,190 @@ bpf_program__attach_iter(struct bpf_program *prog, free(link); pr_warn("prog '%s': failed to attach to iterator: %s\n", prog->name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); - return ERR_PTR(link_fd); + return libbpf_err_ptr(link_fd); } link->fd = link_fd; return link; } -struct bpf_link *bpf_program__attach(struct bpf_program *prog) +static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link) { - const struct bpf_sec_def *sec_def; + *link = bpf_program__attach_iter(prog, NULL); + return libbpf_get_error(*link); +} + +struct bpf_link *bpf_program__attach_netfilter(const struct bpf_program *prog, + const struct bpf_netfilter_opts *opts) +{ + LIBBPF_OPTS(bpf_link_create_opts, lopts); + struct bpf_link *link; + int prog_fd, link_fd; + + if (!OPTS_VALID(opts, bpf_netfilter_opts)) + return libbpf_err_ptr(-EINVAL); + + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warn("prog '%s': can't attach before loaded\n", prog->name); + return libbpf_err_ptr(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return libbpf_err_ptr(-ENOMEM); + + link->detach = &bpf_link__detach_fd; + + lopts.netfilter.pf = OPTS_GET(opts, pf, 0); + lopts.netfilter.hooknum = OPTS_GET(opts, hooknum, 0); + lopts.netfilter.priority = OPTS_GET(opts, priority, 0); + lopts.netfilter.flags = OPTS_GET(opts, flags, 0); + + link_fd = bpf_link_create(prog_fd, 0, BPF_NETFILTER, &lopts); + if (link_fd < 0) { + char errmsg[STRERR_BUFSIZE]; - sec_def = find_sec_def(prog->sec_name); - if (!sec_def || !sec_def->attach_fn) - return ERR_PTR(-ESRCH); + link_fd = -errno; + free(link); + pr_warn("prog '%s': failed to attach to netfilter: %s\n", + prog->name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); + return libbpf_err_ptr(link_fd); + } + link->fd = link_fd; - return sec_def->attach_fn(sec_def, prog); + return link; } +struct bpf_link *bpf_program__attach(const struct bpf_program *prog) +{ + struct bpf_link *link = NULL; + int err; + + if (!prog->sec_def || !prog->sec_def->prog_attach_fn) + return libbpf_err_ptr(-EOPNOTSUPP); + + err = prog->sec_def->prog_attach_fn(prog, prog->sec_def->cookie, &link); + if (err) + return libbpf_err_ptr(err); + + /* When calling bpf_program__attach() explicitly, auto-attach support + * is expected to work, so NULL returned link is considered an error. + * This is different for skeleton's attach, see comment in + * bpf_object__attach_skeleton(). + */ + if (!link) + return libbpf_err_ptr(-EOPNOTSUPP); + + return link; +} + +struct bpf_link_struct_ops { + struct bpf_link link; + int map_fd; +}; + static int bpf_link__detach_struct_ops(struct bpf_link *link) { + struct bpf_link_struct_ops *st_link; __u32 zero = 0; - if (bpf_map_delete_elem(link->fd, &zero)) - return -errno; + st_link = container_of(link, struct bpf_link_struct_ops, link); - return 0; + if (st_link->map_fd < 0) + /* w/o a real link */ + return bpf_map_delete_elem(link->fd, &zero); + + return close(link->fd); } -struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map) +struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map) { - struct bpf_struct_ops *st_ops; - struct bpf_link *link; - __u32 i, zero = 0; - int err; + struct bpf_link_struct_ops *link; + __u32 zero = 0; + int err, fd; if (!bpf_map__is_struct_ops(map) || map->fd == -1) - return ERR_PTR(-EINVAL); + return libbpf_err_ptr(-EINVAL); link = calloc(1, sizeof(*link)); if (!link) - return ERR_PTR(-EINVAL); - - st_ops = map->st_ops; - for (i = 0; i < btf_vlen(st_ops->type); i++) { - struct bpf_program *prog = st_ops->progs[i]; - void *kern_data; - int prog_fd; + return libbpf_err_ptr(-EINVAL); + + /* kern_vdata should be prepared during the loading phase. */ + err = bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0); + /* It can be EBUSY if the map has been used to create or + * update a link before. We don't allow updating the value of + * a struct_ops once it is set. That ensures that the value + * never changed. So, it is safe to skip EBUSY. + */ + if (err && (!(map->def.map_flags & BPF_F_LINK) || err != -EBUSY)) { + free(link); + return libbpf_err_ptr(err); + } - if (!prog) - continue; + link->link.detach = bpf_link__detach_struct_ops; - prog_fd = bpf_program__fd(prog); - kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i]; - *(unsigned long *)kern_data = prog_fd; + if (!(map->def.map_flags & BPF_F_LINK)) { + /* w/o a real link */ + link->link.fd = map->fd; + link->map_fd = -1; + return &link->link; } - err = bpf_map_update_elem(map->fd, &zero, st_ops->kern_vdata, 0); - if (err) { - err = -errno; + fd = bpf_link_create(map->fd, 0, BPF_STRUCT_OPS, NULL); + if (fd < 0) { free(link); - return ERR_PTR(err); + return libbpf_err_ptr(fd); } - link->detach = bpf_link__detach_struct_ops; - link->fd = map->fd; + link->link.fd = fd; + link->map_fd = map->fd; - return link; + return &link->link; } -enum bpf_perf_event_ret -bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size, - void **copy_mem, size_t *copy_size, - bpf_perf_event_print_t fn, void *private_data) +/* + * Swap the back struct_ops of a link with a new struct_ops map. + */ +int bpf_link__update_map(struct bpf_link *link, const struct bpf_map *map) +{ + struct bpf_link_struct_ops *st_ops_link; + __u32 zero = 0; + int err; + + if (!bpf_map__is_struct_ops(map) || !map_is_created(map)) + return -EINVAL; + + st_ops_link = container_of(link, struct bpf_link_struct_ops, link); + /* Ensure the type of a link is correct */ + if (st_ops_link->map_fd < 0) + return -EINVAL; + + err = bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0); + /* It can be EBUSY if the map has been used to create or + * update a link before. We don't allow updating the value of + * a struct_ops once it is set. That ensures that the value + * never changed. So, it is safe to skip EBUSY. + */ + if (err && err != -EBUSY) + return err; + + err = bpf_link_update(link->fd, map->fd, NULL); + if (err < 0) + return err; + + st_ops_link->map_fd = map->fd; + + return 0; +} + +typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(struct perf_event_header *hdr, + void *private_data); + +static enum bpf_perf_event_ret +perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size, + void **copy_mem, size_t *copy_size, + bpf_perf_event_print_t fn, void *private_data) { struct perf_event_mmap_page *header = mmap_mem; __u64 data_head = ring_buffer_read_head(header); @@ -9853,7 +12821,7 @@ bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size, } ring_buffer_write_tail(header, data_tail); - return ret; + return libbpf_err(ret); } struct perf_buffer; @@ -9990,39 +12958,60 @@ static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, struct perf_buffer_params *p); struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt, + perf_buffer_sample_fn sample_cb, + perf_buffer_lost_fn lost_cb, + void *ctx, const struct perf_buffer_opts *opts) { + const size_t attr_sz = sizeof(struct perf_event_attr); struct perf_buffer_params p = {}; - struct perf_event_attr attr = { 0, }; + struct perf_event_attr attr; + __u32 sample_period; + + if (!OPTS_VALID(opts, perf_buffer_opts)) + return libbpf_err_ptr(-EINVAL); + sample_period = OPTS_GET(opts, sample_period, 1); + if (!sample_period) + sample_period = 1; + + memset(&attr, 0, attr_sz); + attr.size = attr_sz; attr.config = PERF_COUNT_SW_BPF_OUTPUT; attr.type = PERF_TYPE_SOFTWARE; attr.sample_type = PERF_SAMPLE_RAW; - attr.sample_period = 1; - attr.wakeup_events = 1; + attr.sample_period = sample_period; + attr.wakeup_events = sample_period; p.attr = &attr; - p.sample_cb = opts ? opts->sample_cb : NULL; - p.lost_cb = opts ? opts->lost_cb : NULL; - p.ctx = opts ? opts->ctx : NULL; + p.sample_cb = sample_cb; + p.lost_cb = lost_cb; + p.ctx = ctx; - return __perf_buffer__new(map_fd, page_cnt, &p); + return libbpf_ptr(__perf_buffer__new(map_fd, page_cnt, &p)); } -struct perf_buffer * -perf_buffer__new_raw(int map_fd, size_t page_cnt, - const struct perf_buffer_raw_opts *opts) +struct perf_buffer *perf_buffer__new_raw(int map_fd, size_t page_cnt, + struct perf_event_attr *attr, + perf_buffer_event_fn event_cb, void *ctx, + const struct perf_buffer_raw_opts *opts) { struct perf_buffer_params p = {}; - p.attr = opts->attr; - p.event_cb = opts->event_cb; - p.ctx = opts->ctx; - p.cpu_cnt = opts->cpu_cnt; - p.cpus = opts->cpus; - p.map_keys = opts->map_keys; + if (!attr) + return libbpf_err_ptr(-EINVAL); + + if (!OPTS_VALID(opts, perf_buffer_raw_opts)) + return libbpf_err_ptr(-EINVAL); + + p.attr = attr; + p.event_cb = event_cb; + p.ctx = ctx; + p.cpu_cnt = OPTS_GET(opts, cpu_cnt, 0); + p.cpus = OPTS_GET(opts, cpus, NULL); + p.map_keys = OPTS_GET(opts, map_keys, NULL); - return __perf_buffer__new(map_fd, page_cnt, &p); + return libbpf_ptr(__perf_buffer__new(map_fd, page_cnt, &p)); } static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, @@ -10036,7 +13025,7 @@ static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, __u32 map_info_len; int err, i, j, n; - if (page_cnt & (page_cnt - 1)) { + if (page_cnt == 0 || (page_cnt & (page_cnt - 1))) { pr_warn("page count should be power of two, but is %zu\n", page_cnt); return ERR_PTR(-EINVAL); @@ -10045,7 +13034,7 @@ static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, /* best-effort sanity checks */ memset(&map, 0, sizeof(map)); map_info_len = sizeof(map); - err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len); + err = bpf_map_get_info_by_fd(map_fd, &map, &map_info_len); if (err) { err = -errno; /* if BPF_OBJ_GET_INFO_BY_FD is supported, will return @@ -10224,10 +13213,10 @@ static int perf_buffer__process_records(struct perf_buffer *pb, { enum bpf_perf_event_ret ret; - ret = bpf_perf_event_read_simple(cpu_buf->base, pb->mmap_size, - pb->page_size, &cpu_buf->buf, - &cpu_buf->buf_size, - perf_buffer__process_record, cpu_buf); + ret = perf_event_read_simple(cpu_buf->base, pb->mmap_size, + pb->page_size, &cpu_buf->buf, + &cpu_buf->buf_size, + perf_buffer__process_record, cpu_buf); if (ret != LIBBPF_PERF_EVENT_CONT) return ret; return 0; @@ -10243,16 +13232,19 @@ int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms) int i, cnt, err; cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms); + if (cnt < 0) + return -errno; + for (i = 0; i < cnt; i++) { struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr; err = perf_buffer__process_records(pb, cpu_buf); if (err) { pr_warn("error while processing records: %d\n", err); - return err; + return libbpf_err(err); } } - return cnt < 0 ? -errno : cnt; + return cnt; } /* Return number of PERF_EVENT_ARRAY map slots set up by this perf_buffer @@ -10273,15 +13265,31 @@ int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx) struct perf_cpu_buf *cpu_buf; if (buf_idx >= pb->cpu_cnt) - return -EINVAL; + return libbpf_err(-EINVAL); cpu_buf = pb->cpu_bufs[buf_idx]; if (!cpu_buf) - return -ENOENT; + return libbpf_err(-ENOENT); return cpu_buf->fd; } +int perf_buffer__buffer(struct perf_buffer *pb, int buf_idx, void **buf, size_t *buf_size) +{ + struct perf_cpu_buf *cpu_buf; + + if (buf_idx >= pb->cpu_cnt) + return libbpf_err(-EINVAL); + + cpu_buf = pb->cpu_bufs[buf_idx]; + if (!cpu_buf) + return libbpf_err(-ENOENT); + + *buf = cpu_buf->base; + *buf_size = pb->mmap_size; + return 0; +} + /* * Consume data from perf ring buffer corresponding to slot *buf_idx* in * PERF_EVENT_ARRAY BPF map without waiting/polling. If there is no data to @@ -10295,11 +13303,11 @@ int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx) struct perf_cpu_buf *cpu_buf; if (buf_idx >= pb->cpu_cnt) - return -EINVAL; + return libbpf_err(-EINVAL); cpu_buf = pb->cpu_bufs[buf_idx]; if (!cpu_buf) - return -ENOENT; + return libbpf_err(-ENOENT); return perf_buffer__process_records(pb, cpu_buf); } @@ -10317,280 +13325,54 @@ int perf_buffer__consume(struct perf_buffer *pb) err = perf_buffer__process_records(pb, cpu_buf); if (err) { pr_warn("perf_buffer: failed to process records in buffer #%d: %d\n", i, err); - return err; + return libbpf_err(err); } } return 0; } -struct bpf_prog_info_array_desc { - int array_offset; /* e.g. offset of jited_prog_insns */ - int count_offset; /* e.g. offset of jited_prog_len */ - int size_offset; /* > 0: offset of rec size, - * < 0: fix size of -size_offset - */ -}; - -static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = { - [BPF_PROG_INFO_JITED_INSNS] = { - offsetof(struct bpf_prog_info, jited_prog_insns), - offsetof(struct bpf_prog_info, jited_prog_len), - -1, - }, - [BPF_PROG_INFO_XLATED_INSNS] = { - offsetof(struct bpf_prog_info, xlated_prog_insns), - offsetof(struct bpf_prog_info, xlated_prog_len), - -1, - }, - [BPF_PROG_INFO_MAP_IDS] = { - offsetof(struct bpf_prog_info, map_ids), - offsetof(struct bpf_prog_info, nr_map_ids), - -(int)sizeof(__u32), - }, - [BPF_PROG_INFO_JITED_KSYMS] = { - offsetof(struct bpf_prog_info, jited_ksyms), - offsetof(struct bpf_prog_info, nr_jited_ksyms), - -(int)sizeof(__u64), - }, - [BPF_PROG_INFO_JITED_FUNC_LENS] = { - offsetof(struct bpf_prog_info, jited_func_lens), - offsetof(struct bpf_prog_info, nr_jited_func_lens), - -(int)sizeof(__u32), - }, - [BPF_PROG_INFO_FUNC_INFO] = { - offsetof(struct bpf_prog_info, func_info), - offsetof(struct bpf_prog_info, nr_func_info), - offsetof(struct bpf_prog_info, func_info_rec_size), - }, - [BPF_PROG_INFO_LINE_INFO] = { - offsetof(struct bpf_prog_info, line_info), - offsetof(struct bpf_prog_info, nr_line_info), - offsetof(struct bpf_prog_info, line_info_rec_size), - }, - [BPF_PROG_INFO_JITED_LINE_INFO] = { - offsetof(struct bpf_prog_info, jited_line_info), - offsetof(struct bpf_prog_info, nr_jited_line_info), - offsetof(struct bpf_prog_info, jited_line_info_rec_size), - }, - [BPF_PROG_INFO_PROG_TAGS] = { - offsetof(struct bpf_prog_info, prog_tags), - offsetof(struct bpf_prog_info, nr_prog_tags), - -(int)sizeof(__u8) * BPF_TAG_SIZE, - }, - -}; - -static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info, - int offset) -{ - __u32 *array = (__u32 *)info; - - if (offset >= 0) - return array[offset / sizeof(__u32)]; - return -(int)offset; -} - -static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info, - int offset) -{ - __u64 *array = (__u64 *)info; - - if (offset >= 0) - return array[offset / sizeof(__u64)]; - return -(int)offset; -} - -static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset, - __u32 val) -{ - __u32 *array = (__u32 *)info; - - if (offset >= 0) - array[offset / sizeof(__u32)] = val; -} - -static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset, - __u64 val) -{ - __u64 *array = (__u64 *)info; - - if (offset >= 0) - array[offset / sizeof(__u64)] = val; -} - -struct bpf_prog_info_linear * -bpf_program__get_prog_info_linear(int fd, __u64 arrays) -{ - struct bpf_prog_info_linear *info_linear; - struct bpf_prog_info info = {}; - __u32 info_len = sizeof(info); - __u32 data_len = 0; - int i, err; - void *ptr; - - if (arrays >> BPF_PROG_INFO_LAST_ARRAY) - return ERR_PTR(-EINVAL); - - /* step 1: get array dimensions */ - err = bpf_obj_get_info_by_fd(fd, &info, &info_len); - if (err) { - pr_debug("can't get prog info: %s", strerror(errno)); - return ERR_PTR(-EFAULT); - } - - /* step 2: calculate total size of all arrays */ - for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { - bool include_array = (arrays & (1UL << i)) > 0; - struct bpf_prog_info_array_desc *desc; - __u32 count, size; - - desc = bpf_prog_info_array_desc + i; - - /* kernel is too old to support this field */ - if (info_len < desc->array_offset + sizeof(__u32) || - info_len < desc->count_offset + sizeof(__u32) || - (desc->size_offset > 0 && info_len < desc->size_offset)) - include_array = false; - - if (!include_array) { - arrays &= ~(1UL << i); /* clear the bit */ - continue; - } - - count = bpf_prog_info_read_offset_u32(&info, desc->count_offset); - size = bpf_prog_info_read_offset_u32(&info, desc->size_offset); - - data_len += count * size; - } - - /* step 3: allocate continuous memory */ - data_len = roundup(data_len, sizeof(__u64)); - info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len); - if (!info_linear) - return ERR_PTR(-ENOMEM); - - /* step 4: fill data to info_linear->info */ - info_linear->arrays = arrays; - memset(&info_linear->info, 0, sizeof(info)); - ptr = info_linear->data; - - for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { - struct bpf_prog_info_array_desc *desc; - __u32 count, size; - - if ((arrays & (1UL << i)) == 0) - continue; - - desc = bpf_prog_info_array_desc + i; - count = bpf_prog_info_read_offset_u32(&info, desc->count_offset); - size = bpf_prog_info_read_offset_u32(&info, desc->size_offset); - bpf_prog_info_set_offset_u32(&info_linear->info, - desc->count_offset, count); - bpf_prog_info_set_offset_u32(&info_linear->info, - desc->size_offset, size); - bpf_prog_info_set_offset_u64(&info_linear->info, - desc->array_offset, - ptr_to_u64(ptr)); - ptr += count * size; - } - - /* step 5: call syscall again to get required arrays */ - err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len); - if (err) { - pr_debug("can't get prog info: %s", strerror(errno)); - free(info_linear); - return ERR_PTR(-EFAULT); - } - - /* step 6: verify the data */ - for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { - struct bpf_prog_info_array_desc *desc; - __u32 v1, v2; - - if ((arrays & (1UL << i)) == 0) - continue; - - desc = bpf_prog_info_array_desc + i; - v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset); - v2 = bpf_prog_info_read_offset_u32(&info_linear->info, - desc->count_offset); - if (v1 != v2) - pr_warn("%s: mismatch in element count\n", __func__); - - v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset); - v2 = bpf_prog_info_read_offset_u32(&info_linear->info, - desc->size_offset); - if (v1 != v2) - pr_warn("%s: mismatch in rec size\n", __func__); - } - - /* step 7: update info_len and data_len */ - info_linear->info_len = sizeof(struct bpf_prog_info); - info_linear->data_len = data_len; - - return info_linear; -} - -void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear) -{ - int i; - - for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { - struct bpf_prog_info_array_desc *desc; - __u64 addr, offs; - - if ((info_linear->arrays & (1UL << i)) == 0) - continue; - - desc = bpf_prog_info_array_desc + i; - addr = bpf_prog_info_read_offset_u64(&info_linear->info, - desc->array_offset); - offs = addr - ptr_to_u64(info_linear->data); - bpf_prog_info_set_offset_u64(&info_linear->info, - desc->array_offset, offs); - } -} - -void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear) -{ - int i; - - for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { - struct bpf_prog_info_array_desc *desc; - __u64 addr, offs; - - if ((info_linear->arrays & (1UL << i)) == 0) - continue; - - desc = bpf_prog_info_array_desc + i; - offs = bpf_prog_info_read_offset_u64(&info_linear->info, - desc->array_offset); - addr = offs + ptr_to_u64(info_linear->data); - bpf_prog_info_set_offset_u64(&info_linear->info, - desc->array_offset, addr); - } -} - int bpf_program__set_attach_target(struct bpf_program *prog, int attach_prog_fd, const char *attach_func_name) { - int btf_id; + int btf_obj_fd = 0, btf_id = 0, err; - if (!prog || attach_prog_fd < 0 || !attach_func_name) - return -EINVAL; + if (!prog || attach_prog_fd < 0) + return libbpf_err(-EINVAL); + + if (prog->obj->loaded) + return libbpf_err(-EINVAL); + + if (attach_prog_fd && !attach_func_name) { + /* remember attach_prog_fd and let bpf_program__load() find + * BTF ID during the program load + */ + prog->attach_prog_fd = attach_prog_fd; + return 0; + } - if (attach_prog_fd) + if (attach_prog_fd) { btf_id = libbpf_find_prog_btf_id(attach_func_name, attach_prog_fd); - else - btf_id = libbpf_find_vmlinux_btf_id(attach_func_name, - prog->expected_attach_type); + if (btf_id < 0) + return libbpf_err(btf_id); + } else { + if (!attach_func_name) + return libbpf_err(-EINVAL); - if (btf_id < 0) - return btf_id; + /* load btf_vmlinux, if not yet */ + err = bpf_object__load_vmlinux_btf(prog->obj, true); + if (err) + return libbpf_err(err); + err = find_kernel_btf_id(prog->obj, attach_func_name, + prog->expected_attach_type, + &btf_obj_fd, &btf_id); + if (err) + return libbpf_err(err); + } prog->attach_btf_id = btf_id; + prog->attach_btf_obj_fd = btf_obj_fd; prog->attach_prog_fd = attach_prog_fd; return 0; } @@ -10650,7 +13432,7 @@ int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz) int fd, err = 0, len; char buf[128]; - fd = open(fcpu, O_RDONLY); + fd = open(fcpu, O_RDONLY | O_CLOEXEC); if (fd < 0) { err = -errno; pr_warn("Failed to open cpu mask file %s: %d\n", fcpu, err); @@ -10685,7 +13467,7 @@ int libbpf_num_possible_cpus(void) err = parse_cpu_mask_file(fcpu, &mask, &n); if (err) - return err; + return libbpf_err(err); tmp_cpus = 0; for (i = 0; i < n; i++) { @@ -10698,6 +13480,49 @@ int libbpf_num_possible_cpus(void) return tmp_cpus; } +static int populate_skeleton_maps(const struct bpf_object *obj, + struct bpf_map_skeleton *maps, + size_t map_cnt) +{ + int i; + + for (i = 0; i < map_cnt; i++) { + struct bpf_map **map = maps[i].map; + const char *name = maps[i].name; + void **mmaped = maps[i].mmaped; + + *map = bpf_object__find_map_by_name(obj, name); + if (!*map) { + pr_warn("failed to find skeleton map '%s'\n", name); + return -ESRCH; + } + + /* externs shouldn't be pre-setup from user code */ + if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_KCONFIG) + *mmaped = (*map)->mmaped; + } + return 0; +} + +static int populate_skeleton_progs(const struct bpf_object *obj, + struct bpf_prog_skeleton *progs, + size_t prog_cnt) +{ + int i; + + for (i = 0; i < prog_cnt; i++) { + struct bpf_program **prog = progs[i].prog; + const char *name = progs[i].name; + + *prog = bpf_object__find_program_by_name(obj, name); + if (!*prog) { + pr_warn("failed to find skeleton program '%s'\n", name); + return -ESRCH; + } + } + return 0; +} + int bpf_object__open_skeleton(struct bpf_object_skeleton *s, const struct bpf_object_open_opts *opts) { @@ -10705,7 +13530,7 @@ int bpf_object__open_skeleton(struct bpf_object_skeleton *s, .object_name = s->name, ); struct bpf_object *obj; - int i; + int err; /* Attempt to preserve opts->object_name, unless overriden by user * explicitly. Overwriting object name for skeletons is discouraged, @@ -10720,44 +13545,99 @@ int bpf_object__open_skeleton(struct bpf_object_skeleton *s, } obj = bpf_object__open_mem(s->data, s->data_sz, &skel_opts); - if (IS_ERR(obj)) { - pr_warn("failed to initialize skeleton BPF object '%s': %ld\n", - s->name, PTR_ERR(obj)); - return PTR_ERR(obj); + err = libbpf_get_error(obj); + if (err) { + pr_warn("failed to initialize skeleton BPF object '%s': %d\n", + s->name, err); + return libbpf_err(err); } *s->obj = obj; + err = populate_skeleton_maps(obj, s->maps, s->map_cnt); + if (err) { + pr_warn("failed to populate skeleton maps for '%s': %d\n", s->name, err); + return libbpf_err(err); + } - for (i = 0; i < s->map_cnt; i++) { - struct bpf_map **map = s->maps[i].map; - const char *name = s->maps[i].name; - void **mmaped = s->maps[i].mmaped; + err = populate_skeleton_progs(obj, s->progs, s->prog_cnt); + if (err) { + pr_warn("failed to populate skeleton progs for '%s': %d\n", s->name, err); + return libbpf_err(err); + } - *map = bpf_object__find_map_by_name(obj, name); - if (!*map) { - pr_warn("failed to find skeleton map '%s'\n", name); - return -ESRCH; - } + return 0; +} - /* externs shouldn't be pre-setup from user code */ - if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_KCONFIG) - *mmaped = (*map)->mmaped; +int bpf_object__open_subskeleton(struct bpf_object_subskeleton *s) +{ + int err, len, var_idx, i; + const char *var_name; + const struct bpf_map *map; + struct btf *btf; + __u32 map_type_id; + const struct btf_type *map_type, *var_type; + const struct bpf_var_skeleton *var_skel; + struct btf_var_secinfo *var; + + if (!s->obj) + return libbpf_err(-EINVAL); + + btf = bpf_object__btf(s->obj); + if (!btf) { + pr_warn("subskeletons require BTF at runtime (object %s)\n", + bpf_object__name(s->obj)); + return libbpf_err(-errno); } - for (i = 0; i < s->prog_cnt; i++) { - struct bpf_program **prog = s->progs[i].prog; - const char *name = s->progs[i].name; + err = populate_skeleton_maps(s->obj, s->maps, s->map_cnt); + if (err) { + pr_warn("failed to populate subskeleton maps: %d\n", err); + return libbpf_err(err); + } - *prog = bpf_object__find_program_by_name(obj, name); - if (!*prog) { - pr_warn("failed to find skeleton program '%s'\n", name); - return -ESRCH; + err = populate_skeleton_progs(s->obj, s->progs, s->prog_cnt); + if (err) { + pr_warn("failed to populate subskeleton maps: %d\n", err); + return libbpf_err(err); + } + + for (var_idx = 0; var_idx < s->var_cnt; var_idx++) { + var_skel = &s->vars[var_idx]; + map = *var_skel->map; + map_type_id = bpf_map__btf_value_type_id(map); + map_type = btf__type_by_id(btf, map_type_id); + + if (!btf_is_datasec(map_type)) { + pr_warn("type for map '%1$s' is not a datasec: %2$s", + bpf_map__name(map), + __btf_kind_str(btf_kind(map_type))); + return libbpf_err(-EINVAL); + } + + len = btf_vlen(map_type); + var = btf_var_secinfos(map_type); + for (i = 0; i < len; i++, var++) { + var_type = btf__type_by_id(btf, var->type); + var_name = btf__name_by_offset(btf, var_type->name_off); + if (strcmp(var_name, var_skel->name) == 0) { + *var_skel->addr = map->mmaped + var->offset; + break; + } } } - return 0; } +void bpf_object__destroy_subskeleton(struct bpf_object_subskeleton *s) +{ + if (!s) + return; + free(s->maps); + free(s->progs); + free(s->vars); + free(s); +} + int bpf_object__load_skeleton(struct bpf_object_skeleton *s) { int i, err; @@ -10765,13 +13645,13 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s) err = bpf_object__load(*s->obj); if (err) { pr_warn("failed to load BPF skeleton '%s': %d\n", s->name, err); - return err; + return libbpf_err(err); } for (i = 0; i < s->map_cnt; i++) { struct bpf_map *map = *s->maps[i].map; size_t mmap_sz = bpf_map_mmap_sz(map); - int prot, map_fd = bpf_map__fd(map); + int prot, map_fd = map->fd; void **mmaped = s->maps[i].mmaped; if (!mmaped) @@ -10782,6 +13662,11 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s) continue; } + if (map->def.type == BPF_MAP_TYPE_ARENA) { + *mmaped = map->mmaped; + continue; + } + if (map->def.map_flags & BPF_F_RDONLY_PROG) prot = PROT_READ; else @@ -10797,14 +13682,13 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s) * as per normal clean up procedure, so we don't need to worry * about it from skeleton's clean up perspective. */ - *mmaped = mmap(map->mmaped, mmap_sz, prot, - MAP_SHARED | MAP_FIXED, map_fd, 0); + *mmaped = mmap(map->mmaped, mmap_sz, prot, MAP_SHARED | MAP_FIXED, map_fd, 0); if (*mmaped == MAP_FAILED) { err = -errno; *mmaped = NULL; pr_warn("failed to re-mmap() map '%s': %d\n", bpf_map__name(map), err); - return err; + return libbpf_err(err); } } @@ -10813,26 +13697,40 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s) int bpf_object__attach_skeleton(struct bpf_object_skeleton *s) { - int i; + int i, err; for (i = 0; i < s->prog_cnt; i++) { struct bpf_program *prog = *s->progs[i].prog; struct bpf_link **link = s->progs[i].link; - const struct bpf_sec_def *sec_def; - if (!prog->load) + if (!prog->autoload || !prog->autoattach) continue; - sec_def = find_sec_def(prog->sec_name); - if (!sec_def || !sec_def->attach_fn) + /* auto-attaching not supported for this program */ + if (!prog->sec_def || !prog->sec_def->prog_attach_fn) continue; - *link = sec_def->attach_fn(sec_def, prog); - if (IS_ERR(*link)) { - pr_warn("failed to auto-attach program '%s': %ld\n", - bpf_program__name(prog), PTR_ERR(*link)); - return PTR_ERR(*link); - } + /* if user already set the link manually, don't attempt auto-attach */ + if (*link) + continue; + + err = prog->sec_def->prog_attach_fn(prog, prog->sec_def->cookie, link); + if (err) { + pr_warn("prog '%s': failed to auto-attach: %d\n", + bpf_program__name(prog), err); + return libbpf_err(err); + } + + /* It's possible that for some SEC() definitions auto-attach + * is supported in some cases (e.g., if definition completely + * specifies target information), but is not in other cases. + * SEC("uprobe") is one such case. If user specified target + * binary and function name, such BPF program can be + * auto-attached. But if not, it shouldn't trigger skeleton's + * attach to fail. It should just be skipped. + * attach_fn signals such case with returning 0 (no error) and + * setting link to NULL. + */ } return 0; @@ -10852,6 +13750,9 @@ void bpf_object__detach_skeleton(struct bpf_object_skeleton *s) void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s) { + if (!s) + return; + if (s->progs) bpf_object__detach_skeleton(s); if (s->obj) |