// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) /* * Common eBPF ELF object loading operations. * * Copyright (C) 2013-2015 Alexei Starovoitov * Copyright (C) 2015 Wang Nan * Copyright (C) 2015 Huawei Inc. * Copyright (C) 2017 Nicira, Inc. */ #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "libbpf.h" #include "bpf.h" #include "btf.h" #include "str_error.h" #ifndef EM_BPF #define EM_BPF 247 #endif #ifndef BPF_FS_MAGIC #define BPF_FS_MAGIC 0xcafe4a11 #endif #define __printf(a, b) __attribute__((format(printf, a, b))) __printf(1, 2) static int __base_pr(const char *format, ...) { va_list args; int err; va_start(args, format); err = vfprintf(stderr, format, args); va_end(args); return err; } static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr; static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr; static __printf(1, 2) libbpf_print_fn_t __pr_debug; #define __pr(func, fmt, ...) \ do { \ if ((func)) \ (func)("libbpf: " fmt, ##__VA_ARGS__); \ } while (0) #define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__) #define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__) #define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__) void libbpf_set_print(libbpf_print_fn_t warn, libbpf_print_fn_t info, libbpf_print_fn_t debug) { __pr_warning = warn; __pr_info = info; __pr_debug = debug; } #define STRERR_BUFSIZE 128 #define CHECK_ERR(action, err, out) do { \ err = action; \ if (err) \ goto out; \ } while(0) /* Copied from tools/perf/util/util.h */ #ifndef zfree # define zfree(ptr) ({ free(*ptr); *ptr = NULL; }) #endif #ifndef zclose # define zclose(fd) ({ \ int ___err = 0; \ if ((fd) >= 0) \ ___err = close((fd)); \ fd = -1; \ ___err; }) #endif #ifdef HAVE_LIBELF_MMAP_SUPPORT # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP #else # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ #endif /* * bpf_prog should be a better name but it has been used in * linux/filter.h. */ struct bpf_program { /* Index in elf obj file, for relocation use. */ int idx; char *name; int prog_ifindex; char *section_name; /* section_name with / replaced by _; makes recursive pinning * in bpf_object__pin_programs easier */ char *pin_name; struct bpf_insn *insns; size_t insns_cnt, main_prog_cnt; enum bpf_prog_type type; struct reloc_desc { enum { RELO_LD64, RELO_CALL, } type; int insn_idx; union { int map_idx; int text_off; }; } *reloc_desc; int nr_reloc; struct { int nr; int *fds; } instances; bpf_program_prep_t preprocessor; struct bpf_object *obj; void *priv; bpf_program_clear_priv_t clear_priv; enum bpf_attach_type expected_attach_type; int btf_fd; void *func_info; __u32 func_info_rec_size; __u32 func_info_len; }; struct bpf_map { int fd; char *name; size_t offset; int map_ifindex; struct bpf_map_def def; __u32 btf_key_type_id; __u32 btf_value_type_id; void *priv; bpf_map_clear_priv_t clear_priv; }; static LIST_HEAD(bpf_objects_list); struct bpf_object { char license[64]; __u32 kern_version; struct bpf_program *programs; size_t nr_programs; struct bpf_map *maps; size_t nr_maps; bool loaded; bool has_pseudo_calls; /* * Information when doing elf related work. Only valid if fd * is valid. */ struct { int fd; void *obj_buf; size_t obj_buf_sz; Elf *elf; GElf_Ehdr ehdr; Elf_Data *symbols; size_t strtabidx; struct { GElf_Shdr shdr; Elf_Data *data; } *reloc; int nr_reloc; int maps_shndx; int text_shndx; } efile; /* * All loaded bpf_object is linked in a list, which is * hidden to caller. bpf_objects__ handlers deal with * all objects. */ struct list_head list; struct btf *btf; struct btf_ext *btf_ext; void *priv; bpf_object_clear_priv_t clear_priv; char path[]; }; #define obj_elf_valid(o) ((o)->efile.elf) 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_warning("Internal error: instances.nr is %d\n", prog->instances.nr); } prog->instances.nr = -1; zfree(&prog->instances.fds); zclose(prog->btf_fd); zfree(&prog->func_info); } 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->section_name); zfree(&prog->pin_name); zfree(&prog->insns); zfree(&prog->reloc_desc); prog->nr_reloc = 0; prog->insns_cnt = 0; prog->idx = -1; } static char *__bpf_program__pin_name(struct bpf_program *prog) { char *name, *p; name = p = strdup(prog->section_name); while ((p = strchr(p, '/'))) *p = '_'; return name; } static int bpf_program__init(void *data, size_t size, char *section_name, int idx, struct bpf_program *prog) { if (size < sizeof(struct bpf_insn)) { pr_warning("corrupted section '%s'\n", section_name); return -EINVAL; } bzero(prog, sizeof(*prog)); prog->section_name = strdup(section_name); if (!prog->section_name) { pr_warning("failed to alloc name for prog under section(%d) %s\n", idx, section_name); goto errout; } prog->pin_name = __bpf_program__pin_name(prog); if (!prog->pin_name) { pr_warning("failed to alloc pin name for prog under section(%d) %s\n", idx, section_name); goto errout; } prog->insns = malloc(size); if (!prog->insns) { pr_warning("failed to alloc insns for prog under section %s\n", section_name); goto errout; } prog->insns_cnt = size / sizeof(struct bpf_insn); memcpy(prog->insns, data, prog->insns_cnt * sizeof(struct bpf_insn)); prog->idx = idx; prog->instances.fds = NULL; prog->instances.nr = -1; prog->type = BPF_PROG_TYPE_KPROBE; prog->btf_fd = -1; return 0; errout: bpf_program__exit(prog); return -ENOMEM; } static int bpf_object__add_program(struct bpf_object *obj, void *data, size_t size, char *section_name, int idx) { struct bpf_program prog, *progs; int nr_progs, err; err = bpf_program__init(data, size, section_name, idx, &prog); if (err) return err; progs = obj->programs; nr_progs = obj->nr_programs; progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0])); if (!progs) { /* * In this case the original obj->programs * is still valid, so don't need special treat for * bpf_close_object(). */ pr_warning("failed to alloc a new program under section '%s'\n", section_name); bpf_program__exit(&prog); return -ENOMEM; } pr_debug("found program %s\n", prog.section_name); obj->programs = progs; obj->nr_programs = nr_progs + 1; prog.obj = obj; progs[nr_progs] = prog; return 0; } static int bpf_object__init_prog_names(struct bpf_object *obj) { Elf_Data *symbols = obj->efile.symbols; struct bpf_program *prog; size_t pi, si; for (pi = 0; pi < obj->nr_programs; pi++) { const char *name = NULL; prog = &obj->programs[pi]; for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name; si++) { GElf_Sym sym; if (!gelf_getsym(symbols, si, &sym)) continue; if (sym.st_shndx != prog->idx) continue; if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL) continue; name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, sym.st_name); if (!name) { pr_warning("failed to get sym name string for prog %s\n", prog->section_name); return -LIBBPF_ERRNO__LIBELF; } } if (!name && prog->idx == obj->efile.text_shndx) name = ".text"; if (!name) { pr_warning("failed to find sym for prog %s\n", prog->section_name); return -EINVAL; } prog->name = strdup(name); if (!prog->name) { pr_warning("failed to allocate memory for prog sym %s\n", name); return -ENOMEM; } } return 0; } static struct bpf_object *bpf_object__new(const char *path, void *obj_buf, size_t obj_buf_sz) { struct bpf_object *obj; obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1); if (!obj) { pr_warning("alloc memory failed for %s\n", path); return ERR_PTR(-ENOMEM); } strcpy(obj->path, path); obj->efile.fd = -1; /* * Caller of this function should also calls * bpf_object__elf_finish() after data collection to return * obj_buf to user. If not, we should duplicate the buffer to * avoid user freeing them before elf finish. */ obj->efile.obj_buf = obj_buf; obj->efile.obj_buf_sz = obj_buf_sz; obj->efile.maps_shndx = -1; 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)) return; if (obj->efile.elf) { elf_end(obj->efile.elf); obj->efile.elf = NULL; } obj->efile.symbols = NULL; zfree(&obj->efile.reloc); obj->efile.nr_reloc = 0; zclose(obj->efile.fd); obj->efile.obj_buf = NULL; obj->efile.obj_buf_sz = 0; } static int bpf_object__elf_init(struct bpf_object *obj) { int err = 0; GElf_Ehdr *ep; if (obj_elf_valid(obj)) { pr_warning("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(obj->efile.obj_buf, obj->efile.obj_buf_sz); } else { obj->efile.fd = open(obj->path, O_RDONLY); if (obj->efile.fd < 0) { char errmsg[STRERR_BUFSIZE]; char *cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warning("failed to open %s: %s\n", obj->path, cp); return -errno; } obj->efile.elf = elf_begin(obj->efile.fd, LIBBPF_ELF_C_READ_MMAP, NULL); } if (!obj->efile.elf) { pr_warning("failed to open %s as ELF file\n", obj->path); err = -LIBBPF_ERRNO__LIBELF; goto errout; } if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) { pr_warning("failed to get EHDR from %s\n", obj->path); err = -LIBBPF_ERRNO__FORMAT; goto errout; } ep = &obj->efile.ehdr; /* Old LLVM set e_machine to EM_NONE */ if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) { pr_warning("%s is not an eBPF object file\n", obj->path); err = -LIBBPF_ERRNO__FORMAT; goto errout; } return 0; errout: bpf_object__elf_finish(obj); return err; } static int bpf_object__check_endianness(struct bpf_object *obj) { static unsigned int const endian = 1; switch (obj->efile.ehdr.e_ident[EI_DATA]) { case ELFDATA2LSB: /* We are big endian, BPF obj is little endian. */ if (*(unsigned char const *)&endian != 1) goto mismatch; break; case ELFDATA2MSB: /* We are little endian, BPF obj is big endian. */ if (*(unsigned char const *)&endian != 0) goto mismatch; break; default: return -LIBBPF_ERRNO__ENDIAN; } return 0; mismatch: pr_warning("Error: endianness mismatch.\n"); return -LIBBPF_ERRNO__ENDIAN; } 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)); pr_debug("license of %s is %s\n", obj->path, obj->license); return 0; } static int bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size) { __u32 kver; if (size != sizeof(kver)) { pr_warning("invalid kver section in %s\n", obj->path); return -LIBBPF_ERRNO__FORMAT; } memcpy(&kver, data, sizeof(kver)); obj->kern_version = kver; pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version); return 0; } static int compare_bpf_map(const void *_a, const void *_b) { const struct bpf_map *a = _a; const struct bpf_map *b = _b; return a->offset - b->offset; } static int bpf_object__init_maps(struct bpf_object *obj, int flags) { bool strict = !(flags & MAPS_RELAX_COMPAT); int i, map_idx, map_def_sz, nr_maps = 0; Elf_Scn *scn; Elf_Data *data; Elf_Data *symbols = obj->efile.symbols; if (obj->efile.maps_shndx < 0) return -EINVAL; if (!symbols) return -EINVAL; scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx); if (scn) data = elf_getdata(scn, NULL); if (!scn || !data) { pr_warning("failed to get Elf_Data from map section %d\n", obj->efile.maps_shndx); 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. */ for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) { GElf_Sym sym; if (!gelf_getsym(symbols, i, &sym)) continue; if (sym.st_shndx != obj->efile.maps_shndx) continue; nr_maps++; } /* Alloc obj->maps and fill nr_maps. */ pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path, nr_maps, data->d_size); if (!nr_maps) return 0; /* Assume equally sized map definitions */ map_def_sz = data->d_size / nr_maps; if (!data->d_size || (data->d_size % nr_maps) != 0) { pr_warning("unable to determine map definition size " "section %s, %d maps in %zd bytes\n", obj->path, nr_maps, data->d_size); return -EINVAL; } obj->maps = calloc(nr_maps, sizeof(obj->maps[0])); if (!obj->maps) { pr_warning("alloc maps for object failed\n"); return -ENOMEM; } obj->nr_maps = nr_maps; /* * fill all fd with -1 so won't close incorrect * fd (fd=0 is stdin) when failure (zclose won't close * negative fd)). */ for (i = 0; i < nr_maps; i++) obj->maps[i].fd = -1; /* * Fill obj->maps using data in "maps" section. */ for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) { GElf_Sym sym; const char *map_name; struct bpf_map_def *def; if (!gelf_getsym(symbols, i, &sym)) continue; if (sym.st_shndx != obj->efile.maps_shndx) continue; map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, sym.st_name); obj->maps[map_idx].offset = sym.st_value; if (sym.st_value + map_def_sz > data->d_size) { pr_warning("corrupted maps section in %s: last map \"%s\" too small\n", obj->path, map_name); return -EINVAL; } obj->maps[map_idx].name = strdup(map_name); if (!obj->maps[map_idx].name) { pr_warning("failed to alloc map name\n"); return -ENOMEM; } pr_debug("map %d is \"%s\"\n", map_idx, obj->maps[map_idx].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(&obj->maps[map_idx].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_warning("maps section in %s: \"%s\" " "has unrecognized, non-zero " "options\n", obj->path, map_name); if (strict) return -EINVAL; } } memcpy(&obj->maps[map_idx].def, def, sizeof(struct bpf_map_def)); } map_idx++; } qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map); return 0; } static bool section_have_execinstr(struct bpf_object *obj, int idx) { Elf_Scn *scn; GElf_Shdr sh; scn = elf_getscn(obj->efile.elf, idx); if (!scn) return false; if (gelf_getshdr(scn, &sh) != &sh) return false; if (sh.sh_flags & SHF_EXECINSTR) return true; return false; } static int bpf_object__elf_collect(struct bpf_object *obj, int flags) { Elf *elf = obj->efile.elf; GElf_Ehdr *ep = &obj->efile.ehdr; Elf_Scn *scn = NULL; int idx = 0, err = 0; /* Elf is corrupted/truncated, avoid calling elf_strptr. */ if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) { pr_warning("failed to get e_shstrndx from %s\n", obj->path); return -LIBBPF_ERRNO__FORMAT; } while ((scn = elf_nextscn(elf, scn)) != NULL) { char *name; GElf_Shdr sh; Elf_Data *data; idx++; if (gelf_getshdr(scn, &sh) != &sh) { pr_warning("failed to get section(%d) header from %s\n", idx, obj->path); err = -LIBBPF_ERRNO__FORMAT; goto out; } name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name); if (!name) { pr_warning("failed to get section(%d) name from %s\n", idx, obj->path); err = -LIBBPF_ERRNO__FORMAT; goto out; } data = elf_getdata(scn, 0); if (!data) { pr_warning("failed to get section(%d) data from %s(%s)\n", idx, name, obj->path); err = -LIBBPF_ERRNO__FORMAT; goto out; } pr_debug("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); if (strcmp(name, "license") == 0) err = bpf_object__init_license(obj, data->d_buf, data->d_size); else if (strcmp(name, "version") == 0) err = bpf_object__init_kversion(obj, data->d_buf, data->d_size); else if (strcmp(name, "maps") == 0) obj->efile.maps_shndx = idx; else if (strcmp(name, BTF_ELF_SEC) == 0) { obj->btf = btf__new(data->d_buf, data->d_size, __pr_debug); if (IS_ERR(obj->btf)) { pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n", BTF_ELF_SEC, PTR_ERR(obj->btf)); obj->btf = NULL; } } else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) { obj->btf_ext = btf_ext__new(data->d_buf, data->d_size, __pr_debug); if (IS_ERR(obj->btf_ext)) { pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n", BTF_EXT_ELF_SEC, PTR_ERR(obj->btf_ext)); obj->btf_ext = NULL; } } else if (sh.sh_type == SHT_SYMTAB) { if (obj->efile.symbols) { pr_warning("bpf: multiple SYMTAB in %s\n", obj->path); err = -LIBBPF_ERRNO__FORMAT; } else { obj->efile.symbols = data; obj->efile.strtabidx = sh.sh_link; } } else if ((sh.sh_type == SHT_PROGBITS) && (sh.sh_flags & SHF_EXECINSTR) && (data->d_size > 0)) { if (strcmp(name, ".text") == 0) obj->efile.text_shndx = idx; err = bpf_object__add_program(obj, data->d_buf, data->d_size, name, idx); if (err) { char errmsg[STRERR_BUFSIZE]; char *cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); pr_warning("failed to alloc program %s (%s): %s", name, obj->path, cp); } } else if (sh.sh_type == SHT_REL) { void *reloc = obj->efile.reloc; int nr_reloc = obj->efile.nr_reloc + 1; int sec = sh.sh_info; /* points to other section */ /* Only do relo for section with exec instructions */ if (!section_have_execinstr(obj, sec)) { pr_debug("skip relo %s(%d) for section(%d)\n", name, idx, sec); continue; } reloc = reallocarray(reloc, nr_reloc, sizeof(*obj->efile.reloc)); if (!reloc) { pr_warning("realloc failed\n"); err = -ENOMEM; } else { int n = nr_reloc - 1; obj->efile.reloc = reloc; obj->efile.nr_reloc = nr_reloc; obj->efile.reloc[n].shdr = sh; obj->efile.reloc[n].data = data; } } else { pr_debug("skip section(%d) %s\n", idx, name); } if (err) goto out; } if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) { pr_warning("Corrupted ELF file: index of strtab invalid\n"); return LIBBPF_ERRNO__FORMAT; } if (obj->efile.maps_shndx >= 0) { err = bpf_object__init_maps(obj, flags); if (err) goto out; } err = bpf_object__init_prog_names(obj); out: return err; } static struct bpf_program * bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx) { struct bpf_program *prog; size_t i; for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; if (prog->idx == idx) return prog; } return NULL; } struct bpf_program * bpf_object__find_program_by_title(struct bpf_object *obj, const char *title) { struct bpf_program *pos; bpf_object__for_each_program(pos, obj) { if (pos->section_name && !strcmp(pos->section_name, title)) return pos; } return NULL; } static int bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr, Elf_Data *data, struct bpf_object *obj) { Elf_Data *symbols = obj->efile.symbols; int text_shndx = obj->efile.text_shndx; int maps_shndx = obj->efile.maps_shndx; struct bpf_map *maps = obj->maps; size_t nr_maps = obj->nr_maps; int i, nrels; pr_debug("collecting relocating info for: '%s'\n", prog->section_name); nrels = shdr->sh_size / shdr->sh_entsize; prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels); if (!prog->reloc_desc) { pr_warning("failed to alloc memory in relocation\n"); return -ENOMEM; } prog->nr_reloc = nrels; for (i = 0; i < nrels; i++) { GElf_Sym sym; GElf_Rel rel; unsigned int insn_idx; struct bpf_insn *insns = prog->insns; size_t map_idx; if (!gelf_getrel(data, i, &rel)) { pr_warning("relocation: failed to get %d reloc\n", i); return -LIBBPF_ERRNO__FORMAT; } if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) { pr_warning("relocation: symbol %"PRIx64" not found\n", GELF_R_SYM(rel.r_info)); return -LIBBPF_ERRNO__FORMAT; } pr_debug("relo for %lld value %lld name %d\n", (long long) (rel.r_info >> 32), (long long) sym.st_value, sym.st_name); if (sym.st_shndx != maps_shndx && sym.st_shndx != text_shndx) { pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n", prog->section_name, sym.st_shndx); return -LIBBPF_ERRNO__RELOC; } insn_idx = rel.r_offset / sizeof(struct bpf_insn); pr_debug("relocation: insn_idx=%u\n", insn_idx); if (insns[insn_idx].code == (BPF_JMP | BPF_CALL)) { if (insns[insn_idx].src_reg != BPF_PSEUDO_CALL) { pr_warning("incorrect bpf_call opcode\n"); return -LIBBPF_ERRNO__RELOC; } prog->reloc_desc[i].type = RELO_CALL; prog->reloc_desc[i].insn_idx = insn_idx; prog->reloc_desc[i].text_off = sym.st_value; obj->has_pseudo_calls = true; continue; } if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) { pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n", insn_idx, insns[insn_idx].code); return -LIBBPF_ERRNO__RELOC; } /* TODO: 'maps' is sorted. We can use bsearch to make it faster. */ for (map_idx = 0; map_idx < nr_maps; map_idx++) { if (maps[map_idx].offset == sym.st_value) { pr_debug("relocation: find map %zd (%s) for insn %u\n", map_idx, maps[map_idx].name, insn_idx); break; } } if (map_idx >= nr_maps) { pr_warning("bpf relocation: map_idx %d large than %d\n", (int)map_idx, (int)nr_maps - 1); return -LIBBPF_ERRNO__RELOC; } prog->reloc_desc[i].type = RELO_LD64; prog->reloc_desc[i].insn_idx = insn_idx; prog->reloc_desc[i].map_idx = map_idx; } return 0; } static int bpf_map_find_btf_info(struct bpf_map *map, const struct btf *btf) { const struct btf_type *container_type; const struct btf_member *key, *value; struct bpf_map_def *def = &map->def; const size_t max_name = 256; char container_name[max_name]; __s64 key_size, value_size; __s32 container_id; if (snprintf(container_name, max_name, "____btf_map_%s", map->name) == max_name) { pr_warning("map:%s length of '____btf_map_%s' is too long\n", map->name, map->name); return -EINVAL; } container_id = btf__find_by_name(btf, container_name); if (container_id < 0) { pr_debug("map:%s container_name:%s cannot be found in BTF. Missing BPF_ANNOTATE_KV_PAIR?\n", map->name, container_name); return container_id; } container_type = btf__type_by_id(btf, container_id); if (!container_type) { pr_warning("map:%s cannot find BTF type for container_id:%u\n", map->name, container_id); return -EINVAL; } if (BTF_INFO_KIND(container_type->info) != BTF_KIND_STRUCT || BTF_INFO_VLEN(container_type->info) < 2) { pr_warning("map:%s container_name:%s is an invalid container struct\n", map->name, container_name); return -EINVAL; } key = (struct btf_member *)(container_type + 1); value = key + 1; key_size = btf__resolve_size(btf, key->type); if (key_size < 0) { pr_warning("map:%s invalid BTF key_type_size\n", map->name); return key_size; } if (def->key_size != key_size) { pr_warning("map:%s btf_key_type_size:%u != map_def_key_size:%u\n", map->name, (__u32)key_size, def->key_size); return -EINVAL; } value_size = btf__resolve_size(btf, value->type); if (value_size < 0) { pr_warning("map:%s invalid BTF value_type_size\n", map->name); return value_size; } if (def->value_size != value_size) { pr_warning("map:%s btf_value_type_size:%u != map_def_value_size:%u\n", map->name, (__u32)value_size, def->value_size); return -EINVAL; } map->btf_key_type_id = key->type; map->btf_value_type_id = value->type; return 0; } int bpf_map__reuse_fd(struct bpf_map *map, int fd) { struct bpf_map_info info = {}; __u32 len = sizeof(info); int new_fd, err; char *new_name; err = bpf_obj_get_info_by_fd(fd, &info, &len); if (err) return err; new_name = strdup(info.name); if (!new_name) return -errno; new_fd = open("/", O_RDONLY | O_CLOEXEC); if (new_fd < 0) goto err_free_new_name; new_fd = dup3(fd, new_fd, O_CLOEXEC); if (new_fd < 0) goto err_close_new_fd; err = zclose(map->fd); if (err) 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; map->def.value_size = info.value_size; map->def.max_entries = info.max_entries; map->def.map_flags = info.map_flags; map->btf_key_type_id = info.btf_key_type_id; map->btf_value_type_id = info.btf_value_type_id; return 0; err_close_new_fd: close(new_fd); err_free_new_name: free(new_name); return -errno; } static int bpf_object__create_maps(struct bpf_object *obj) { struct bpf_create_map_attr create_attr = {}; unsigned int i; int err; for (i = 0; i < obj->nr_maps; i++) { struct bpf_map *map = &obj->maps[i]; struct bpf_map_def *def = &map->def; char *cp, errmsg[STRERR_BUFSIZE]; int *pfd = &map->fd; if (map->fd >= 0) { pr_debug("skip map create (preset) %s: fd=%d\n", map->name, map->fd); continue; } create_attr.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.max_entries = def->max_entries; create_attr.btf_fd = 0; create_attr.btf_key_type_id = 0; create_attr.btf_value_type_id = 0; if (obj->btf && !bpf_map_find_btf_info(map, obj->btf)) { 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; } *pfd = bpf_create_map_xattr(&create_attr); if (*pfd < 0 && create_attr.btf_key_type_id) { cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warning("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n", map->name, cp, errno); 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; *pfd = bpf_create_map_xattr(&create_attr); } if (*pfd < 0) { size_t j; err = *pfd; cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warning("failed to create map (name: '%s'): %s\n", map->name, cp); for (j = 0; j < i; j++) zclose(obj->maps[j].fd); return err; } pr_debug("create map %s: fd=%d\n", map->name, *pfd); } return 0; } static int bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj, struct reloc_desc *relo) { struct bpf_insn *insn, *new_insn; struct bpf_program *text; size_t new_cnt; int err; if (relo->type != RELO_CALL) return -LIBBPF_ERRNO__RELOC; if (prog->idx == obj->efile.text_shndx) { pr_warning("relo in .text insn %d into off %d\n", relo->insn_idx, relo->text_off); return -LIBBPF_ERRNO__RELOC; } if (prog->main_prog_cnt == 0) { text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx); if (!text) { pr_warning("no .text section found yet relo into text exist\n"); return -LIBBPF_ERRNO__RELOC; } new_cnt = prog->insns_cnt + text->insns_cnt; new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn)); if (!new_insn) { pr_warning("oom in prog realloc\n"); return -ENOMEM; } if (obj->btf && obj->btf_ext) { err = btf_ext__reloc(obj->btf, obj->btf_ext, text->section_name, prog->insns_cnt, &prog->func_info, &prog->func_info_len); if (err) { pr_warning("error in btf_ext__reloc for sec %s\n", text->section_name); return err; } } memcpy(new_insn + prog->insns_cnt, text->insns, text->insns_cnt * sizeof(*insn)); prog->insns = new_insn; prog->main_prog_cnt = prog->insns_cnt; prog->insns_cnt = new_cnt; pr_debug("added %zd insn from %s to prog %s\n", text->insns_cnt, text->section_name, prog->section_name); } insn = &prog->insns[relo->insn_idx]; insn->imm += prog->main_prog_cnt - relo->insn_idx; return 0; } static int bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj) { int i, err; if (!prog) return 0; if (obj->btf && obj->btf_ext) { err = btf_ext__reloc_init(obj->btf, obj->btf_ext, prog->section_name, &prog->func_info, &prog->func_info_rec_size, &prog->func_info_len); if (err) { pr_warning("err in btf_ext__reloc_init for sec %s\n", prog->section_name); return err; } prog->btf_fd = btf__fd(obj->btf); } if (!prog->reloc_desc) return 0; for (i = 0; i < prog->nr_reloc; i++) { if (prog->reloc_desc[i].type == RELO_LD64) { struct bpf_insn *insns = prog->insns; int insn_idx, map_idx; insn_idx = prog->reloc_desc[i].insn_idx; map_idx = prog->reloc_desc[i].map_idx; if (insn_idx >= (int)prog->insns_cnt) { pr_warning("relocation out of range: '%s'\n", prog->section_name); return -LIBBPF_ERRNO__RELOC; } insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD; insns[insn_idx].imm = obj->maps[map_idx].fd; } else { err = bpf_program__reloc_text(prog, obj, &prog->reloc_desc[i]); if (err) return err; } } zfree(&prog->reloc_desc); prog->nr_reloc = 0; return 0; } static int bpf_object__relocate(struct bpf_object *obj) { struct bpf_program *prog; size_t i; int err; for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; err = bpf_program__relocate(prog, obj); if (err) { pr_warning("failed to relocate '%s'\n", prog->section_name); return err; } } return 0; } static int bpf_object__collect_reloc(struct bpf_object *obj) { int i, err; if (!obj_elf_valid(obj)) { pr_warning("Internal error: elf object is closed\n"); return -LIBBPF_ERRNO__INTERNAL; } for (i = 0; i < obj->efile.nr_reloc; i++) { GElf_Shdr *shdr = &obj->efile.reloc[i].shdr; Elf_Data *data = obj->efile.reloc[i].data; int idx = shdr->sh_info; struct bpf_program *prog; if (shdr->sh_type != SHT_REL) { pr_warning("internal error at %d\n", __LINE__); return -LIBBPF_ERRNO__INTERNAL; } prog = bpf_object__find_prog_by_idx(obj, idx); if (!prog) { pr_warning("relocation failed: no section(%d)\n", idx); return -LIBBPF_ERRNO__RELOC; } err = bpf_program__collect_reloc(prog, shdr, data, obj); if (err) return err; } return 0; } static int load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, char *license, __u32 kern_version, int *pfd, __u32 func_info_cnt) { struct bpf_load_program_attr load_attr; char *cp, errmsg[STRERR_BUFSIZE]; char *log_buf; int ret; memset(&load_attr, 0, sizeof(struct bpf_load_program_attr)); load_attr.prog_type = prog->type; load_attr.expected_attach_type = prog->expected_attach_type; load_attr.name = prog->name; load_attr.insns = insns; load_attr.insns_cnt = insns_cnt; load_attr.license = license; load_attr.kern_version = kern_version; load_attr.prog_ifindex = prog->prog_ifindex; load_attr.prog_btf_fd = prog->btf_fd; load_attr.func_info = prog->func_info; load_attr.func_info_rec_size = prog->func_info_rec_size; load_attr.func_info_cnt = func_info_cnt; if (!load_attr.insns || !load_attr.insns_cnt) return -EINVAL; log_buf = malloc(BPF_LOG_BUF_SIZE); if (!log_buf) pr_warning("Alloc log buffer for bpf loader error, continue without log\n"); ret = bpf_load_program_xattr(&load_attr, log_buf, BPF_LOG_BUF_SIZE); if (ret >= 0) { *pfd = ret; ret = 0; goto out; } ret = -LIBBPF_ERRNO__LOAD; cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warning("load bpf program failed: %s\n", cp); if (log_buf && log_buf[0] != '\0') { ret = -LIBBPF_ERRNO__VERIFY; pr_warning("-- BEGIN DUMP LOG ---\n"); pr_warning("\n%s\n", log_buf); pr_warning("-- END LOG --\n"); } else if (load_attr.insns_cnt >= BPF_MAXINSNS) { pr_warning("Program too large (%zu insns), at most %d insns\n", load_attr.insns_cnt, BPF_MAXINSNS); ret = -LIBBPF_ERRNO__PROG2BIG; } else { /* Wrong program type? */ if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) { 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 (log_buf) ret = -LIBBPF_ERRNO__KVER; } out: free(log_buf); return ret; } int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_version) { __u32 func_info_cnt; int err = 0, fd, i; if (prog->func_info_len == 0) func_info_cnt = 0; else func_info_cnt = prog->func_info_len / prog->func_info_rec_size; if (prog->instances.nr < 0 || !prog->instances.fds) { if (prog->preprocessor) { pr_warning("Internal error: can't load program '%s'\n", prog->section_name); return -LIBBPF_ERRNO__INTERNAL; } prog->instances.fds = malloc(sizeof(int)); if (!prog->instances.fds) { pr_warning("Not enough memory for BPF fds\n"); return -ENOMEM; } prog->instances.nr = 1; prog->instances.fds[0] = -1; } if (!prog->preprocessor) { if (prog->instances.nr != 1) { pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n", prog->section_name, prog->instances.nr); } err = load_program(prog, prog->insns, prog->insns_cnt, license, kern_version, &fd, func_info_cnt); 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; bzero(&result, sizeof(result)); err = preprocessor(prog, i, prog->insns, prog->insns_cnt, &result); if (err) { pr_warning("Preprocessing the %dth instance of program '%s' failed\n", i, prog->section_name); goto out; } if (!result.new_insn_ptr || !result.new_insn_cnt) { pr_debug("Skip loading the %dth instance of program '%s'\n", i, prog->section_name); prog->instances.fds[i] = -1; if (result.pfd) *result.pfd = -1; continue; } err = load_program(prog, result.new_insn_ptr, result.new_insn_cnt, license, kern_version, &fd, func_info_cnt); if (err) { pr_warning("Loading the %dth instance of program '%s' failed\n", i, prog->section_name); goto out; } if (result.pfd) *result.pfd = fd; prog->instances.fds[i] = fd; } out: if (err) pr_warning("failed to load program '%s'\n", prog->section_name); zfree(&prog->insns); prog->insns_cnt = 0; return err; } static bool bpf_program__is_function_storage(struct bpf_program *prog, struct bpf_object *obj) { return prog->idx == obj->efile.text_shndx && obj->has_pseudo_calls; } static int bpf_object__load_progs(struct bpf_object *obj) { size_t i; int err; for (i = 0; i < obj->nr_programs; i++) { if (bpf_program__is_function_storage(&obj->programs[i], obj)) continue; err = bpf_program__load(&obj->programs[i], obj->license, obj->kern_version); if (err) return err; } return 0; } static bool bpf_prog_type__needs_kver(enum bpf_prog_type type) { switch (type) { case BPF_PROG_TYPE_SOCKET_FILTER: case BPF_PROG_TYPE_SCHED_CLS: case BPF_PROG_TYPE_SCHED_ACT: case BPF_PROG_TYPE_XDP: case BPF_PROG_TYPE_CGROUP_SKB: case BPF_PROG_TYPE_CGROUP_SOCK: case BPF_PROG_TYPE_LWT_IN: case BPF_PROG_TYPE_LWT_OUT: case BPF_PROG_TYPE_LWT_XMIT: case BPF_PROG_TYPE_LWT_SEG6LOCAL: case BPF_PROG_TYPE_SOCK_OPS: case BPF_PROG_TYPE_SK_SKB: case BPF_PROG_TYPE_CGROUP_DEVICE: case BPF_PROG_TYPE_SK_MSG: case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: case BPF_PROG_TYPE_LIRC_MODE2: case BPF_PROG_TYPE_SK_REUSEPORT: case BPF_PROG_TYPE_FLOW_DISSECTOR: return false; case BPF_PROG_TYPE_UNSPEC: case BPF_PROG_TYPE_KPROBE: case BPF_PROG_TYPE_TRACEPOINT: case BPF_PROG_TYPE_PERF_EVENT: case BPF_PROG_TYPE_RAW_TRACEPOINT: default: return true; } } static int bpf_object__validate(struct bpf_object *obj, bool needs_kver) { if (needs_kver && obj->kern_version == 0) { pr_warning("%s doesn't provide kernel version\n", obj->path); return -LIBBPF_ERRNO__KVERSION; } return 0; } static struct bpf_object * __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz, bool needs_kver, int flags) { struct bpf_object *obj; int err; if (elf_version(EV_CURRENT) == EV_NONE) { pr_warning("failed to init libelf for %s\n", path); return ERR_PTR(-LIBBPF_ERRNO__LIBELF); } obj = bpf_object__new(path, obj_buf, obj_buf_sz); if (IS_ERR(obj)) return obj; CHECK_ERR(bpf_object__elf_init(obj), err, out); CHECK_ERR(bpf_object__check_endianness(obj), err, out); CHECK_ERR(bpf_object__elf_collect(obj, flags), err, out); CHECK_ERR(bpf_object__collect_reloc(obj), err, out); CHECK_ERR(bpf_object__validate(obj, needs_kver), err, out); bpf_object__elf_finish(obj); return obj; out: bpf_object__close(obj); return ERR_PTR(err); } struct bpf_object *__bpf_object__open_xattr(struct bpf_object_open_attr *attr, int flags) { /* param validation */ if (!attr->file) return NULL; pr_debug("loading %s\n", attr->file); return __bpf_object__open(attr->file, NULL, 0, bpf_prog_type__needs_kver(attr->prog_type), flags); } 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_buffer(void *obj_buf, size_t obj_buf_sz, const char *name) { char tmp_name[64]; /* param validation */ if (!obj_buf || obj_buf_sz <= 0) return NULL; if (!name) { snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx", (unsigned long)obj_buf, (unsigned long)obj_buf_sz); tmp_name[sizeof(tmp_name) - 1] = '\0'; name = tmp_name; } pr_debug("loading object '%s' from buffer\n", name); return __bpf_object__open(name, obj_buf, obj_buf_sz, true, true); } int bpf_object__unload(struct bpf_object *obj) { size_t i; if (!obj) return -EINVAL; for (i = 0; i < obj->nr_maps; i++) zclose(obj->maps[i].fd); for (i = 0; i < obj->nr_programs; i++) bpf_program__unload(&obj->programs[i]); return 0; } int bpf_object__load(struct bpf_object *obj) { int err; if (!obj) return -EINVAL; if (obj->loaded) { pr_warning("object should not be loaded twice\n"); return -EINVAL; } obj->loaded = true; CHECK_ERR(bpf_object__create_maps(obj), err, out); CHECK_ERR(bpf_object__relocate(obj), err, out); CHECK_ERR(bpf_object__load_progs(obj), err, out); return 0; out: bpf_object__unload(obj); pr_warning("failed to load object '%s'\n", obj->path); return err; } static int check_path(const char *path) { char *cp, errmsg[STRERR_BUFSIZE]; struct statfs st_fs; char *dname, *dir; int err = 0; if (path == NULL) return -EINVAL; dname = strdup(path); if (dname == NULL) return -ENOMEM; dir = dirname(dname); if (statfs(dir, &st_fs)) { cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warning("failed to statfs %s: %s\n", dir, cp); err = -errno; } free(dname); if (!err && st_fs.f_type != BPF_FS_MAGIC) { pr_warning("specified path %s is not on BPF FS\n", path); err = -EINVAL; } return err; } int bpf_program__pin_instance(struct bpf_program *prog, const char *path, int instance) { char *cp, errmsg[STRERR_BUFSIZE]; int err; err = check_path(path); if (err) return err; if (prog == NULL) { pr_warning("invalid program pointer\n"); return -EINVAL; } if (instance < 0 || instance >= prog->instances.nr) { pr_warning("invalid prog instance %d of prog %s (max %d)\n", instance, prog->section_name, prog->instances.nr); return -EINVAL; } if (bpf_obj_pin(prog->instances.fds[instance], path)) { cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warning("failed to pin program: %s\n", cp); return -errno; } pr_debug("pinned program '%s'\n", path); return 0; } int bpf_program__unpin_instance(struct bpf_program *prog, const char *path, int instance) { int err; err = check_path(path); if (err) return err; if (prog == NULL) { pr_warning("invalid program pointer\n"); return -EINVAL; } if (instance < 0 || instance >= prog->instances.nr) { pr_warning("invalid prog instance %d of prog %s (max %d)\n", instance, prog->section_name, prog->instances.nr); return -EINVAL; } err = unlink(path); if (err != 0) return -errno; pr_debug("unpinned program '%s'\n", path); return 0; } static int make_dir(const char *path) { char *cp, errmsg[STRERR_BUFSIZE]; int err = 0; if (mkdir(path, 0700) && errno != EEXIST) err = -errno; if (err) { cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); pr_warning("failed to mkdir %s: %s\n", path, cp); } return err; } int bpf_program__pin(struct bpf_program *prog, const char *path) { int i, err; err = check_path(path); if (err) return err; if (prog == NULL) { pr_warning("invalid program pointer\n"); return -EINVAL; } if (prog->instances.nr <= 0) { pr_warning("no instances of prog %s to pin\n", prog->section_name); return -EINVAL; } if (prog->instances.nr == 1) { /* don't create subdirs when pinning single instance */ return bpf_program__pin_instance(prog, path, 0); } err = make_dir(path); if (err) return err; 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; } 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_warning("invalid program pointer\n"); return -EINVAL; } if (prog->instances.nr <= 0) { pr_warning("no instances of prog %s to pin\n", prog->section_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); if (err) return -errno; return 0; } int bpf_map__pin(struct bpf_map *map, const char *path) { char *cp, errmsg[STRERR_BUFSIZE]; int err; err = check_path(path); if (err) return err; if (map == NULL) { pr_warning("invalid map pointer\n"); return -EINVAL; } if (bpf_obj_pin(map->fd, path)) { cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warning("failed to pin map: %s\n", cp); return -errno; } pr_debug("pinned map '%s'\n", path); return 0; } int bpf_map__unpin(struct bpf_map *map, const char *path) { int err; err = check_path(path); if (err) return err; if (map == NULL) { pr_warning("invalid map pointer\n"); return -EINVAL; } err = unlink(path); if (err != 0) return -errno; pr_debug("unpinned map '%s'\n", path); return 0; } int bpf_object__pin_maps(struct bpf_object *obj, const char *path) { struct bpf_map *map; int err; if (!obj) return -ENOENT; if (!obj->loaded) { pr_warning("object not yet loaded; load it first\n"); return -ENOENT; } err = make_dir(path); if (err) return err; bpf_map__for_each(map, obj) { char buf[PATH_MAX]; int len; 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; goto err_unpin_maps; } err = bpf_map__pin(map, buf); if (err) goto err_unpin_maps; } return 0; err_unpin_maps: while ((map = bpf_map__prev(map, obj))) { char buf[PATH_MAX]; int len; len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map)); if (len < 0) continue; else if (len >= PATH_MAX) continue; bpf_map__unpin(map, buf); } return err; } int bpf_object__unpin_maps(struct bpf_object *obj, const char *path) { struct bpf_map *map; int err; if (!obj) return -ENOENT; bpf_map__for_each(map, obj) { char buf[PATH_MAX]; 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 = bpf_map__unpin(map, buf); if (err) return err; } return 0; } int bpf_object__pin_programs(struct bpf_object *obj, const char *path) { struct bpf_program *prog; int err; if (!obj) return -ENOENT; if (!obj->loaded) { pr_warning("object not yet loaded; load it first\n"); return -ENOENT; } err = make_dir(path); if (err) return err; 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; goto err_unpin_programs; } err = bpf_program__pin(prog, buf); if (err) goto err_unpin_programs; } 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) continue; bpf_program__unpin(prog, buf); } return err; } int bpf_object__unpin_programs(struct bpf_object *obj, const char *path) { struct bpf_program *prog; int err; if (!obj) return -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 = bpf_program__unpin(prog, buf); if (err) return err; } return 0; } int bpf_object__pin(struct bpf_object *obj, const char *path) { int err; err = bpf_object__pin_maps(obj, path); if (err) return err; err = bpf_object__pin_programs(obj, path); if (err) { bpf_object__unpin_maps(obj, path); return err; } return 0; } void bpf_object__close(struct bpf_object *obj) { size_t i; if (!obj) return; if (obj->clear_priv) obj->clear_priv(obj, obj->priv); bpf_object__elf_finish(obj); bpf_object__unload(obj); btf__free(obj->btf); btf_ext__free(obj->btf_ext); for (i = 0; i < obj->nr_maps; i++) { zfree(&obj->maps[i].name); if (obj->maps[i].clear_priv) obj->maps[i].clear_priv(&obj->maps[i], obj->maps[i].priv); obj->maps[i].priv = NULL; obj->maps[i].clear_priv = NULL; } zfree(&obj->maps); obj->nr_maps = 0; if (obj->programs && obj->nr_programs) { for (i = 0; i < obj->nr_programs; i++) bpf_program__exit(&obj->programs[i]); } 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); /* Empty list is noticed here so don't need checking on entry. */ if (&next->list == &bpf_objects_list) return NULL; return next; } const char *bpf_object__name(struct bpf_object *obj) { return obj ? obj->path : ERR_PTR(-EINVAL); } unsigned int bpf_object__kversion(struct bpf_object *obj) { return obj ? obj->kern_version : 0; } 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) { if (obj->priv && obj->clear_priv) obj->clear_priv(obj, obj->priv); obj->priv = priv; obj->clear_priv = clear_priv; return 0; } void *bpf_object__priv(struct bpf_object *obj) { return obj ? obj->priv : ERR_PTR(-EINVAL); } static struct bpf_program * __bpf_program__iter(struct bpf_program *p, struct bpf_object *obj, bool forward) { size_t nr_programs = obj->nr_programs; ssize_t idx; if (!nr_programs) return NULL; if (!p) /* Iter from the beginning */ return forward ? &obj->programs[0] : &obj->programs[nr_programs - 1]; if (p->obj != obj) { pr_warning("error: program handler doesn't match object\n"); return NULL; } idx = (p - obj->programs) + (forward ? 1 : -1); if (idx >= obj->nr_programs || idx < 0) return NULL; return &obj->programs[idx]; } struct bpf_program * bpf_program__next(struct bpf_program *prev, struct bpf_object *obj) { struct bpf_program *prog = prev; do { prog = __bpf_program__iter(prog, obj, true); } while (prog && bpf_program__is_function_storage(prog, obj)); return prog; } struct bpf_program * bpf_program__prev(struct bpf_program *next, struct bpf_object *obj) { struct bpf_program *prog = next; do { prog = __bpf_program__iter(prog, obj, false); } while (prog && bpf_program__is_function_storage(prog, 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(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; } const char *bpf_program__title(struct bpf_program *prog, bool needs_copy) { const char *title; title = prog->section_name; if (needs_copy) { title = strdup(title); if (!title) { pr_warning("failed to strdup program title\n"); return ERR_PTR(-ENOMEM); } } return title; } int bpf_program__fd(struct bpf_program *prog) { return bpf_program__nth_fd(prog, 0); } int bpf_program__set_prep(struct bpf_program *prog, int nr_instances, bpf_program_prep_t prep) { int *instances_fds; if (nr_instances <= 0 || !prep) return -EINVAL; if (prog->instances.nr > 0 || prog->instances.fds) { pr_warning("Can't set pre-processor after loading\n"); return -EINVAL; } instances_fds = malloc(sizeof(int) * nr_instances); if (!instances_fds) { pr_warning("alloc memory failed for fds\n"); return -ENOMEM; } /* 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; return 0; } int bpf_program__nth_fd(struct bpf_program *prog, int n) { int fd; if (!prog) return -EINVAL; if (n >= prog->instances.nr || n < 0) { pr_warning("Can't get the %dth fd from program %s: only %d instances\n", n, prog->section_name, prog->instances.nr); return -EINVAL; } fd = prog->instances.fds[n]; if (fd < 0) { pr_warning("%dth instance of program '%s' is invalid\n", n, prog->section_name); return -ENOENT; } return fd; } void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type) { prog->type = type; } static bool bpf_program__is_type(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(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(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); void bpf_program__set_expected_attach_type(struct bpf_program *prog, enum bpf_attach_type type) { prog->expected_attach_type = type; } #define BPF_PROG_SEC_IMPL(string, ptype, eatype, is_attachable, atype) \ { string, sizeof(string) - 1, ptype, eatype, is_attachable, atype } /* Programs that can NOT be attached. */ #define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0) /* Programs that can be attached. */ #define BPF_APROG_SEC(string, ptype, atype) \ BPF_PROG_SEC_IMPL(string, ptype, 0, 1, atype) /* Programs that must specify expected attach type at load time. */ #define BPF_EAPROG_SEC(string, ptype, eatype) \ BPF_PROG_SEC_IMPL(string, ptype, eatype, 1, eatype) /* 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) static const struct { const char *sec; size_t len; enum bpf_prog_type prog_type; enum bpf_attach_type expected_attach_type; int is_attachable; enum bpf_attach_type attach_type; } section_names[] = { BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER), BPF_PROG_SEC("kprobe/", BPF_PROG_TYPE_KPROBE), BPF_PROG_SEC("kretprobe/", BPF_PROG_TYPE_KPROBE), BPF_PROG_SEC("classifier", BPF_PROG_TYPE_SCHED_CLS), BPF_PROG_SEC("action", BPF_PROG_TYPE_SCHED_ACT), BPF_PROG_SEC("tracepoint/", BPF_PROG_TYPE_TRACEPOINT), BPF_PROG_SEC("raw_tracepoint/", BPF_PROG_TYPE_RAW_TRACEPOINT), BPF_PROG_SEC("xdp", BPF_PROG_TYPE_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_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), }; #undef BPF_PROG_SEC_IMPL #undef BPF_PROG_SEC #undef BPF_APROG_SEC #undef BPF_EAPROG_SEC #undef BPF_APROG_COMPAT int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type, enum bpf_attach_type *expected_attach_type) { int i; if (!name) return -EINVAL; for (i = 0; i < ARRAY_SIZE(section_names); i++) { if (strncmp(name, section_names[i].sec, section_names[i].len)) continue; *prog_type = section_names[i].prog_type; *expected_attach_type = section_names[i].expected_attach_type; return 0; } return -EINVAL; } int libbpf_attach_type_by_name(const char *name, enum bpf_attach_type *attach_type) { int i; if (!name) return -EINVAL; for (i = 0; i < ARRAY_SIZE(section_names); i++) { if (strncmp(name, section_names[i].sec, section_names[i].len)) continue; if (!section_names[i].is_attachable) return -EINVAL; *attach_type = section_names[i].attach_type; return 0; } return -EINVAL; } static int bpf_program__identify_section(struct bpf_program *prog, enum bpf_prog_type *prog_type, enum bpf_attach_type *expected_attach_type) { return libbpf_prog_type_by_name(prog->section_name, prog_type, expected_attach_type); } int bpf_map__fd(struct bpf_map *map) { return map ? map->fd : -EINVAL; } const struct bpf_map_def *bpf_map__def(struct bpf_map *map) { return map ? &map->def : ERR_PTR(-EINVAL); } const char *bpf_map__name(struct bpf_map *map) { return map ? map->name : NULL; } __u32 bpf_map__btf_key_type_id(const struct bpf_map *map) { return map ? map->btf_key_type_id : 0; } __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) { if (!map) return -EINVAL; if (map->priv) { if (map->clear_priv) map->clear_priv(map, map->priv); } map->priv = priv; map->clear_priv = clear_priv; return 0; } void *bpf_map__priv(struct bpf_map *map) { return map ? map->priv : ERR_PTR(-EINVAL); } bool bpf_map__is_offload_neutral(struct bpf_map *map) { return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY; } void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex) { map->map_ifindex = ifindex; } static struct bpf_map * __bpf_map__iter(struct bpf_map *m, struct bpf_object *obj, int i) { ssize_t idx; struct bpf_map *s, *e; if (!obj || !obj->maps) return NULL; s = obj->maps; e = obj->maps + obj->nr_maps; if ((m < s) || (m >= e)) { pr_warning("error in %s: map handler doesn't belong to object\n", __func__); return NULL; } idx = (m - obj->maps) + i; if (idx >= obj->nr_maps || idx < 0) return NULL; return &obj->maps[idx]; } struct bpf_map * bpf_map__next(struct bpf_map *prev, struct bpf_object *obj) { if (prev == NULL) return obj->maps; return __bpf_map__iter(prev, obj, 1); } struct bpf_map * bpf_map__prev(struct bpf_map *next, struct bpf_object *obj) { if (next == NULL) { if (!obj->nr_maps) return NULL; return obj->maps + obj->nr_maps - 1; } return __bpf_map__iter(next, obj, -1); } struct bpf_map * bpf_object__find_map_by_name(struct bpf_object *obj, const char *name) { struct bpf_map *pos; bpf_map__for_each(pos, obj) { if (pos->name && !strcmp(pos->name, name)) return pos; } return NULL; } struct bpf_map * bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset) { int i; for (i = 0; i < obj->nr_maps; i++) { if (obj->maps[i].offset == offset) return &obj->maps[i]; } return ERR_PTR(-ENOENT); } long libbpf_get_error(const void *ptr) { if (IS_ERR(ptr)) return PTR_ERR(ptr); return 0; } int bpf_prog_load(const char *file, enum bpf_prog_type type, struct bpf_object **pobj, int *prog_fd) { struct bpf_prog_load_attr attr; memset(&attr, 0, sizeof(struct bpf_prog_load_attr)); attr.file = file; attr.prog_type = type; attr.expected_attach_type = 0; return bpf_prog_load_xattr(&attr, pobj, prog_fd); } int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr, struct bpf_object **pobj, int *prog_fd) { struct bpf_object_open_attr open_attr = { .file = attr->file, .prog_type = attr->prog_type, }; struct bpf_program *prog, *first_prog = NULL; enum bpf_attach_type expected_attach_type; enum bpf_prog_type prog_type; struct bpf_object *obj; struct bpf_map *map; int err; if (!attr) return -EINVAL; if (!attr->file) return -EINVAL; obj = bpf_object__open_xattr(&open_attr); if (IS_ERR_OR_NULL(obj)) return -ENOENT; bpf_object__for_each_program(prog, obj) { /* * If type is not specified, try to guess it based on * section name. */ prog_type = attr->prog_type; prog->prog_ifindex = attr->ifindex; expected_attach_type = attr->expected_attach_type; if (prog_type == BPF_PROG_TYPE_UNSPEC) { err = bpf_program__identify_section(prog, &prog_type, &expected_attach_type); if (err < 0) { pr_warning("failed to guess program type based on section name %s\n", prog->section_name); bpf_object__close(obj); return -EINVAL; } } bpf_program__set_type(prog, prog_type); bpf_program__set_expected_attach_type(prog, expected_attach_type); if (!first_prog) first_prog = prog; } bpf_map__for_each(map, obj) { if (!bpf_map__is_offload_neutral(map)) map->map_ifindex = attr->ifindex; } if (!first_prog) { pr_warning("object file doesn't contain bpf program\n"); bpf_object__close(obj); return -ENOENT; } err = bpf_object__load(obj); if (err) { bpf_object__close(obj); return -EINVAL; } *pobj = obj; *prog_fd = bpf_program__fd(first_prog); return 0; } 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) { struct perf_event_mmap_page *header = mmap_mem; __u64 data_head = ring_buffer_read_head(header); __u64 data_tail = header->data_tail; void *base = ((__u8 *)header) + page_size; int ret = LIBBPF_PERF_EVENT_CONT; struct perf_event_header *ehdr; size_t ehdr_size; while (data_head != data_tail) { ehdr = base + (data_tail & (mmap_size - 1)); ehdr_size = ehdr->size; if (((void *)ehdr) + ehdr_size > base + mmap_size) { void *copy_start = ehdr; size_t len_first = base + mmap_size - copy_start; size_t len_secnd = ehdr_size - len_first; if (*copy_size < ehdr_size) { free(*copy_mem); *copy_mem = malloc(ehdr_size); if (!*copy_mem) { *copy_size = 0; ret = LIBBPF_PERF_EVENT_ERROR; break; } *copy_size = ehdr_size; } memcpy(*copy_mem, copy_start, len_first); memcpy(*copy_mem + len_first, base, len_secnd); ehdr = *copy_mem; } ret = fn(ehdr, private_data); data_tail += ehdr_size; if (ret != LIBBPF_PERF_EVENT_CONT) break; } ring_buffer_write_tail(header, data_tail); return ret; }