diff options
Diffstat (limited to 'tools/lib/bpf/btf.c')
| -rw-r--r-- | tools/lib/bpf/btf.c | 3632 |
1 files changed, 2755 insertions, 877 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 3d1c25fc97ae..d88647da2c7f 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) /* Copyright (c) 2018 Facebook */ +#include <byteswap.h> #include <endian.h> #include <stdio.h> #include <stdlib.h> @@ -20,9 +21,7 @@ #include "libbpf.h" #include "libbpf_internal.h" #include "hashmap.h" - -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 +#include "strset.h" #define BTF_MAX_NR_TYPES 0x7fffffffU #define BTF_MAX_STR_OFFSET 0x7fffffffU @@ -30,17 +29,98 @@ static struct btf_type btf_void; struct btf { - union { - struct btf_header *hdr; - void *data; - }; - struct btf_type **types; - const char *strings; - void *nohdr_data; + /* raw BTF data in native endianness */ + void *raw_data; + /* raw BTF data in non-native endianness */ + void *raw_data_swapped; + __u32 raw_size; + /* whether target endianness differs from the native one */ + bool swapped_endian; + + /* + * When BTF is loaded from an ELF or raw memory it is stored + * in a contiguous memory block. The hdr, type_data, and, strs_data + * point inside that memory region to their respective parts of BTF + * representation: + * + * +--------------------------------+ + * | Header | Types | Strings | + * +--------------------------------+ + * ^ ^ ^ + * | | | + * hdr | | + * types_data-+ | + * strs_data------------+ + * + * If BTF data is later modified, e.g., due to types added or + * removed, BTF deduplication performed, etc, this contiguous + * representation is broken up into three independently allocated + * memory regions to be able to modify them independently. + * raw_data is nulled out at that point, but can be later allocated + * and cached again if user calls btf__raw_data(), at which point + * raw_data will contain a contiguous copy of header, types, and + * strings: + * + * +----------+ +---------+ +-----------+ + * | Header | | Types | | Strings | + * +----------+ +---------+ +-----------+ + * ^ ^ ^ + * | | | + * hdr | | + * types_data----+ | + * strset__data(strs_set)-----+ + * + * +----------+---------+-----------+ + * | Header | Types | Strings | + * raw_data----->+----------+---------+-----------+ + */ + struct btf_header *hdr; + + void *types_data; + size_t types_data_cap; /* used size stored in hdr->type_len */ + + /* type ID to `struct btf_type *` lookup index + * type_offs[0] corresponds to the first non-VOID type: + * - for base BTF it's type [1]; + * - for split BTF it's the first non-base BTF type. + */ + __u32 *type_offs; + size_t type_offs_cap; + /* number of types in this BTF instance: + * - doesn't include special [0] void type; + * - for split BTF counts number of types added on top of base BTF. + */ __u32 nr_types; - __u32 types_size; - __u32 data_size; + /* if not NULL, points to the base BTF on top of which the current + * split BTF is based + */ + struct btf *base_btf; + /* BTF type ID of the first type in this BTF instance: + * - for base BTF it's equal to 1; + * - for split BTF it's equal to biggest type ID of base BTF plus 1. + */ + int start_id; + /* logical string offset of this BTF instance: + * - for base BTF it's equal to 0; + * - for split BTF it's equal to total size of base BTF's string section size. + */ + int start_str_off; + + /* only one of strs_data or strs_set can be non-NULL, depending on + * whether BTF is in a modifiable state (strs_set is used) or not + * (strs_data points inside raw_data) + */ + void *strs_data; + /* a set of unique strings */ + struct strset *strs_set; + /* whether strings are already deduplicated */ + bool strs_deduped; + + /* BTF object FD, if loaded into kernel */ int fd; + + /* Pointer size (in bytes) for a target architecture of this BTF */ + int ptr_sz; }; static inline __u64 ptr_to_u64(const void *ptr) @@ -48,110 +128,166 @@ static inline __u64 ptr_to_u64(const void *ptr) return (__u64) (unsigned long) ptr; } -static int btf_add_type(struct btf *btf, struct btf_type *t) +/* Ensure given dynamically allocated memory region pointed to by *data* with + * capacity of *cap_cnt* elements each taking *elem_sz* bytes has enough + * memory to accommodate *add_cnt* new elements, assuming *cur_cnt* elements + * are already used. At most *max_cnt* elements can be ever allocated. + * If necessary, memory is reallocated and all existing data is copied over, + * new pointer to the memory region is stored at *data, new memory region + * capacity (in number of elements) is stored in *cap. + * On success, memory pointer to the beginning of unused memory is returned. + * On error, NULL is returned. + */ +void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, + size_t cur_cnt, size_t max_cnt, size_t add_cnt) { - if (btf->types_size - btf->nr_types < 2) { - struct btf_type **new_types; - __u32 expand_by, new_size; + size_t new_cnt; + void *new_data; - if (btf->types_size == BTF_MAX_NR_TYPES) - return -E2BIG; + if (cur_cnt + add_cnt <= *cap_cnt) + return *data + cur_cnt * elem_sz; - expand_by = max(btf->types_size >> 2, 16U); - new_size = min(BTF_MAX_NR_TYPES, btf->types_size + expand_by); + /* requested more than the set limit */ + if (cur_cnt + add_cnt > max_cnt) + return NULL; - new_types = realloc(btf->types, sizeof(*new_types) * new_size); - if (!new_types) - return -ENOMEM; + new_cnt = *cap_cnt; + new_cnt += new_cnt / 4; /* expand by 25% */ + if (new_cnt < 16) /* but at least 16 elements */ + new_cnt = 16; + if (new_cnt > max_cnt) /* but not exceeding a set limit */ + new_cnt = max_cnt; + if (new_cnt < cur_cnt + add_cnt) /* also ensure we have enough memory */ + new_cnt = cur_cnt + add_cnt; + + new_data = libbpf_reallocarray(*data, new_cnt, elem_sz); + if (!new_data) + return NULL; - if (btf->nr_types == 0) - new_types[0] = &btf_void; + /* zero out newly allocated portion of memory */ + memset(new_data + (*cap_cnt) * elem_sz, 0, (new_cnt - *cap_cnt) * elem_sz); - btf->types = new_types; - btf->types_size = new_size; - } + *data = new_data; + *cap_cnt = new_cnt; + return new_data + cur_cnt * elem_sz; +} + +/* Ensure given dynamically allocated memory region has enough allocated space + * to accommodate *need_cnt* elements of size *elem_sz* bytes each + */ +int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt) +{ + void *p; + + if (need_cnt <= *cap_cnt) + return 0; + + p = libbpf_add_mem(data, cap_cnt, elem_sz, *cap_cnt, SIZE_MAX, need_cnt - *cap_cnt); + if (!p) + return -ENOMEM; + + return 0; +} + +static void *btf_add_type_offs_mem(struct btf *btf, size_t add_cnt) +{ + return libbpf_add_mem((void **)&btf->type_offs, &btf->type_offs_cap, sizeof(__u32), + btf->nr_types, BTF_MAX_NR_TYPES, add_cnt); +} + +static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off) +{ + __u32 *p; - btf->types[++(btf->nr_types)] = t; + p = btf_add_type_offs_mem(btf, 1); + if (!p) + return -ENOMEM; + *p = type_off; return 0; } +static void btf_bswap_hdr(struct btf_header *h) +{ + h->magic = bswap_16(h->magic); + h->hdr_len = bswap_32(h->hdr_len); + h->type_off = bswap_32(h->type_off); + h->type_len = bswap_32(h->type_len); + h->str_off = bswap_32(h->str_off); + h->str_len = bswap_32(h->str_len); +} + static int btf_parse_hdr(struct btf *btf) { - const struct btf_header *hdr = btf->hdr; + struct btf_header *hdr = btf->hdr; __u32 meta_left; - if (btf->data_size < sizeof(struct btf_header)) { + if (btf->raw_size < sizeof(struct btf_header)) { pr_debug("BTF header not found\n"); return -EINVAL; } - if (hdr->magic != BTF_MAGIC) { - pr_debug("Invalid BTF magic:%x\n", hdr->magic); - return -EINVAL; - } - - if (hdr->version != BTF_VERSION) { - pr_debug("Unsupported BTF version:%u\n", hdr->version); - return -ENOTSUP; - } - - if (hdr->flags) { - pr_debug("Unsupported BTF flags:%x\n", hdr->flags); - return -ENOTSUP; - } - - meta_left = btf->data_size - sizeof(*hdr); - if (!meta_left) { - pr_debug("BTF has no data\n"); + if (hdr->magic == bswap_16(BTF_MAGIC)) { + btf->swapped_endian = true; + if (bswap_32(hdr->hdr_len) != sizeof(struct btf_header)) { + pr_warn("Can't load BTF with non-native endianness due to unsupported header length %u\n", + bswap_32(hdr->hdr_len)); + return -ENOTSUP; + } + btf_bswap_hdr(hdr); + } else if (hdr->magic != BTF_MAGIC) { + pr_debug("Invalid BTF magic: %x\n", hdr->magic); return -EINVAL; } - if (meta_left < hdr->type_off) { - pr_debug("Invalid BTF type section offset:%u\n", hdr->type_off); + if (btf->raw_size < hdr->hdr_len) { + pr_debug("BTF header len %u larger than data size %u\n", + hdr->hdr_len, btf->raw_size); return -EINVAL; } - if (meta_left < hdr->str_off) { - pr_debug("Invalid BTF string section offset:%u\n", hdr->str_off); + meta_left = btf->raw_size - hdr->hdr_len; + if (meta_left < (long long)hdr->str_off + hdr->str_len) { + pr_debug("Invalid BTF total size: %u\n", btf->raw_size); return -EINVAL; } - if (hdr->type_off >= hdr->str_off) { - pr_debug("BTF type section offset >= string section offset. No type?\n"); + if ((long long)hdr->type_off + hdr->type_len > hdr->str_off) { + pr_debug("Invalid BTF data sections layout: type data at %u + %u, strings data at %u + %u\n", + hdr->type_off, hdr->type_len, hdr->str_off, hdr->str_len); return -EINVAL; } - if (hdr->type_off & 0x02) { + if (hdr->type_off % 4) { pr_debug("BTF type section is not aligned to 4 bytes\n"); return -EINVAL; } - btf->nohdr_data = btf->hdr + 1; - return 0; } static int btf_parse_str_sec(struct btf *btf) { const struct btf_header *hdr = btf->hdr; - const char *start = btf->nohdr_data + hdr->str_off; + const char *start = btf->strs_data; const char *end = start + btf->hdr->str_len; - if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET || - start[0] || end[-1]) { + if (btf->base_btf && hdr->str_len == 0) + return 0; + if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET || end[-1]) { + pr_debug("Invalid BTF string section\n"); + return -EINVAL; + } + if (!btf->base_btf && start[0]) { pr_debug("Invalid BTF string section\n"); return -EINVAL; } - - btf->strings = start; - return 0; } -static int btf_type_size(struct btf_type *t) +static int btf_type_size(const struct btf_type *t) { - int base_size = sizeof(struct btf_type); + const int base_size = sizeof(struct btf_type); __u16 vlen = btf_vlen(t); switch (btf_kind(t)) { @@ -162,11 +298,15 @@ static int btf_type_size(struct btf_type *t) case BTF_KIND_PTR: case BTF_KIND_TYPEDEF: case BTF_KIND_FUNC: + case BTF_KIND_FLOAT: + case BTF_KIND_TYPE_TAG: return base_size; case BTF_KIND_INT: return base_size + sizeof(__u32); case BTF_KIND_ENUM: return base_size + vlen * sizeof(struct btf_enum); + case BTF_KIND_ENUM64: + return base_size + vlen * sizeof(struct btf_enum64); case BTF_KIND_ARRAY: return base_size + sizeof(struct btf_array); case BTF_KIND_STRUCT: @@ -178,6 +318,92 @@ static int btf_type_size(struct btf_type *t) return base_size + sizeof(struct btf_var); case BTF_KIND_DATASEC: return base_size + vlen * sizeof(struct btf_var_secinfo); + case BTF_KIND_DECL_TAG: + return base_size + sizeof(struct btf_decl_tag); + default: + pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t)); + return -EINVAL; + } +} + +static void btf_bswap_type_base(struct btf_type *t) +{ + t->name_off = bswap_32(t->name_off); + t->info = bswap_32(t->info); + t->type = bswap_32(t->type); +} + +static int btf_bswap_type_rest(struct btf_type *t) +{ + struct btf_var_secinfo *v; + struct btf_enum64 *e64; + struct btf_member *m; + struct btf_array *a; + struct btf_param *p; + struct btf_enum *e; + __u16 vlen = btf_vlen(t); + int i; + + switch (btf_kind(t)) { + case BTF_KIND_FWD: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + case BTF_KIND_FLOAT: + case BTF_KIND_TYPE_TAG: + return 0; + case BTF_KIND_INT: + *(__u32 *)(t + 1) = bswap_32(*(__u32 *)(t + 1)); + return 0; + case BTF_KIND_ENUM: + for (i = 0, e = btf_enum(t); i < vlen; i++, e++) { + e->name_off = bswap_32(e->name_off); + e->val = bswap_32(e->val); + } + return 0; + case BTF_KIND_ENUM64: + for (i = 0, e64 = btf_enum64(t); i < vlen; i++, e64++) { + e64->name_off = bswap_32(e64->name_off); + e64->val_lo32 = bswap_32(e64->val_lo32); + e64->val_hi32 = bswap_32(e64->val_hi32); + } + return 0; + case BTF_KIND_ARRAY: + a = btf_array(t); + a->type = bswap_32(a->type); + a->index_type = bswap_32(a->index_type); + a->nelems = bswap_32(a->nelems); + return 0; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + for (i = 0, m = btf_members(t); i < vlen; i++, m++) { + m->name_off = bswap_32(m->name_off); + m->type = bswap_32(m->type); + m->offset = bswap_32(m->offset); + } + return 0; + case BTF_KIND_FUNC_PROTO: + for (i = 0, p = btf_params(t); i < vlen; i++, p++) { + p->name_off = bswap_32(p->name_off); + p->type = bswap_32(p->type); + } + return 0; + case BTF_KIND_VAR: + btf_var(t)->linkage = bswap_32(btf_var(t)->linkage); + return 0; + case BTF_KIND_DATASEC: + for (i = 0, v = btf_var_secinfos(t); i < vlen; i++, v++) { + v->type = bswap_32(v->type); + v->offset = bswap_32(v->offset); + v->size = bswap_32(v->size); + } + return 0; + case BTF_KIND_DECL_TAG: + btf_decl_tag(t)->component_idx = bswap_32(btf_decl_tag(t)->component_idx); + return 0; default: pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t)); return -EINVAL; @@ -187,38 +413,180 @@ static int btf_type_size(struct btf_type *t) static int btf_parse_type_sec(struct btf *btf) { struct btf_header *hdr = btf->hdr; - void *nohdr_data = btf->nohdr_data; - void *next_type = nohdr_data + hdr->type_off; - void *end_type = nohdr_data + hdr->str_off; + void *next_type = btf->types_data; + void *end_type = next_type + hdr->type_len; + int err, type_size; - while (next_type < end_type) { - struct btf_type *t = next_type; - int type_size; - int err; + while (next_type + sizeof(struct btf_type) <= end_type) { + if (btf->swapped_endian) + btf_bswap_type_base(next_type); - type_size = btf_type_size(t); + type_size = btf_type_size(next_type); if (type_size < 0) return type_size; - next_type += type_size; - err = btf_add_type(btf, t); + if (next_type + type_size > end_type) { + pr_warn("BTF type [%d] is malformed\n", btf->start_id + btf->nr_types); + return -EINVAL; + } + + if (btf->swapped_endian && btf_bswap_type_rest(next_type)) + return -EINVAL; + + err = btf_add_type_idx_entry(btf, next_type - btf->types_data); if (err) return err; + + next_type += type_size; + btf->nr_types++; + } + + if (next_type != end_type) { + pr_warn("BTF types data is malformed\n"); + return -EINVAL; } return 0; } -__u32 btf__get_nr_types(const struct btf *btf) +__u32 btf__type_cnt(const struct btf *btf) { - return btf->nr_types; + return btf->start_id + btf->nr_types; +} + +const struct btf *btf__base_btf(const struct btf *btf) +{ + return btf->base_btf; +} + +/* internal helper returning non-const pointer to a type */ +struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id) +{ + if (type_id == 0) + return &btf_void; + if (type_id < btf->start_id) + return btf_type_by_id(btf->base_btf, type_id); + return btf->types_data + btf->type_offs[type_id - btf->start_id]; } const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id) { - if (type_id > btf->nr_types) - return NULL; + if (type_id >= btf->start_id + btf->nr_types) + return errno = EINVAL, NULL; + return btf_type_by_id((struct btf *)btf, type_id); +} + +static int determine_ptr_size(const struct btf *btf) +{ + static const char * const long_aliases[] = { + "long", + "long int", + "int long", + "unsigned long", + "long unsigned", + "unsigned long int", + "unsigned int long", + "long unsigned int", + "long int unsigned", + "int unsigned long", + "int long unsigned", + }; + const struct btf_type *t; + const char *name; + int i, j, n; + + if (btf->base_btf && btf->base_btf->ptr_sz > 0) + return btf->base_btf->ptr_sz; + + n = btf__type_cnt(btf); + for (i = 1; i < n; i++) { + t = btf__type_by_id(btf, i); + if (!btf_is_int(t)) + continue; + + if (t->size != 4 && t->size != 8) + continue; + + name = btf__name_by_offset(btf, t->name_off); + if (!name) + continue; + + for (j = 0; j < ARRAY_SIZE(long_aliases); j++) { + if (strcmp(name, long_aliases[j]) == 0) + return t->size; + } + } + + return -1; +} + +static size_t btf_ptr_sz(const struct btf *btf) +{ + if (!btf->ptr_sz) + ((struct btf *)btf)->ptr_sz = determine_ptr_size(btf); + return btf->ptr_sz < 0 ? sizeof(void *) : btf->ptr_sz; +} + +/* Return pointer size this BTF instance assumes. The size is heuristically + * determined by looking for 'long' or 'unsigned long' integer type and + * recording its size in bytes. If BTF type information doesn't have any such + * type, this function returns 0. In the latter case, native architecture's + * pointer size is assumed, so will be either 4 or 8, depending on + * architecture that libbpf was compiled for. It's possible to override + * guessed value by using btf__set_pointer_size() API. + */ +size_t btf__pointer_size(const struct btf *btf) +{ + if (!btf->ptr_sz) + ((struct btf *)btf)->ptr_sz = determine_ptr_size(btf); - return btf->types[type_id]; + if (btf->ptr_sz < 0) + /* not enough BTF type info to guess */ + return 0; + + return btf->ptr_sz; +} + +/* Override or set pointer size in bytes. Only values of 4 and 8 are + * supported. + */ +int btf__set_pointer_size(struct btf *btf, size_t ptr_sz) +{ + if (ptr_sz != 4 && ptr_sz != 8) + return libbpf_err(-EINVAL); + btf->ptr_sz = ptr_sz; + return 0; +} + +static bool is_host_big_endian(void) +{ +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + return false; +#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ + return true; +#else +# error "Unrecognized __BYTE_ORDER__" +#endif +} + +enum btf_endianness btf__endianness(const struct btf *btf) +{ + if (is_host_big_endian()) + return btf->swapped_endian ? BTF_LITTLE_ENDIAN : BTF_BIG_ENDIAN; + else + return btf->swapped_endian ? BTF_BIG_ENDIAN : BTF_LITTLE_ENDIAN; +} + +int btf__set_endianness(struct btf *btf, enum btf_endianness endian) +{ + if (endian != BTF_LITTLE_ENDIAN && endian != BTF_BIG_ENDIAN) + return libbpf_err(-EINVAL); + + btf->swapped_endian = is_host_big_endian() != (endian == BTF_BIG_ENDIAN); + if (!btf->swapped_endian) { + free(btf->raw_data_swapped); + btf->raw_data_swapped = NULL; + } + return 0; } static bool btf_type_is_void(const struct btf_type *t) @@ -242,35 +610,38 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id) int i; t = btf__type_by_id(btf, type_id); - for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t); - i++) { + for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t); i++) { switch (btf_kind(t)) { case BTF_KIND_INT: case BTF_KIND_STRUCT: case BTF_KIND_UNION: case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: case BTF_KIND_DATASEC: + case BTF_KIND_FLOAT: size = t->size; goto done; case BTF_KIND_PTR: - size = sizeof(void *); + size = btf_ptr_sz(btf); goto done; case BTF_KIND_TYPEDEF: case BTF_KIND_VOLATILE: case BTF_KIND_CONST: case BTF_KIND_RESTRICT: case BTF_KIND_VAR: + case BTF_KIND_DECL_TAG: + case BTF_KIND_TYPE_TAG: type_id = t->type; break; case BTF_KIND_ARRAY: array = btf_array(t); if (nelems && array->nelems > UINT32_MAX / nelems) - return -E2BIG; + return libbpf_err(-E2BIG); nelems *= array->nelems; type_id = array->type; break; default: - return -EINVAL; + return libbpf_err(-EINVAL); } t = btf__type_by_id(btf, type_id); @@ -278,9 +649,9 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id) done: if (size < 0) - return -EINVAL; + return libbpf_err(-EINVAL); if (nelems && size > UINT32_MAX / nelems) - return -E2BIG; + return libbpf_err(-E2BIG); return nelems * size; } @@ -293,13 +664,16 @@ int btf__align_of(const struct btf *btf, __u32 id) switch (kind) { case BTF_KIND_INT: case BTF_KIND_ENUM: - return min(sizeof(void *), (size_t)t->size); + case BTF_KIND_ENUM64: + case BTF_KIND_FLOAT: + return min(btf_ptr_sz(btf), (size_t)t->size); case BTF_KIND_PTR: - return sizeof(void *); + return btf_ptr_sz(btf); case BTF_KIND_TYPEDEF: case BTF_KIND_VOLATILE: case BTF_KIND_CONST: case BTF_KIND_RESTRICT: + case BTF_KIND_TYPE_TAG: return btf__align_of(btf, t->type); case BTF_KIND_ARRAY: return btf__align_of(btf, btf_array(t)->type); @@ -312,7 +686,7 @@ int btf__align_of(const struct btf *btf, __u32 id) for (i = 0; i < vlen; i++, m++) { align = btf__align_of(btf, m->type); if (align <= 0) - return align; + return libbpf_err(align); max_align = max(max_align, align); } @@ -320,7 +694,7 @@ int btf__align_of(const struct btf *btf, __u32 id) } default: pr_warn("unsupported BTF_KIND:%u\n", btf_kind(t)); - return 0; + return errno = EINVAL, 0; } } @@ -339,39 +713,39 @@ int btf__resolve_type(const struct btf *btf, __u32 type_id) } if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t)) - return -EINVAL; + return libbpf_err(-EINVAL); return type_id; } __s32 btf__find_by_name(const struct btf *btf, const char *type_name) { - __u32 i; + __u32 i, nr_types = btf__type_cnt(btf); if (!strcmp(type_name, "void")) return 0; - for (i = 1; i <= btf->nr_types; i++) { - const struct btf_type *t = btf->types[i]; + for (i = 1; i < nr_types; i++) { + const struct btf_type *t = btf__type_by_id(btf, i); const char *name = btf__name_by_offset(btf, t->name_off); if (name && !strcmp(type_name, name)) return i; } - return -ENOENT; + return libbpf_err(-ENOENT); } -__s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name, - __u32 kind) +static __s32 btf_find_by_name_kind(const struct btf *btf, int start_id, + const char *type_name, __u32 kind) { - __u32 i; + __u32 i, nr_types = btf__type_cnt(btf); if (kind == BTF_KIND_UNKN || !strcmp(type_name, "void")) return 0; - for (i = 1; i <= btf->nr_types; i++) { - const struct btf_type *t = btf->types[i]; + for (i = start_id; i < nr_types; i++) { + const struct btf_type *t = btf__type_by_id(btf, i); const char *name; if (btf_kind(t) != kind) @@ -381,23 +755,103 @@ __s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name, return i; } - return -ENOENT; + return libbpf_err(-ENOENT); +} + +__s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name, + __u32 kind) +{ + return btf_find_by_name_kind(btf, btf->start_id, type_name, kind); +} + +__s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name, + __u32 kind) +{ + return btf_find_by_name_kind(btf, 1, type_name, kind); +} + +static bool btf_is_modifiable(const struct btf *btf) +{ + return (void *)btf->hdr != btf->raw_data; } void btf__free(struct btf *btf) { - if (!btf) + if (IS_ERR_OR_NULL(btf)) return; - if (btf->fd != -1) + if (btf->fd >= 0) close(btf->fd); - free(btf->data); - free(btf->types); + if (btf_is_modifiable(btf)) { + /* if BTF was modified after loading, it will have a split + * in-memory representation for header, types, and strings + * sections, so we need to free all of them individually. It + * might still have a cached contiguous raw data present, + * which will be unconditionally freed below. + */ + free(btf->hdr); + free(btf->types_data); + strset__free(btf->strs_set); + } + free(btf->raw_data); + free(btf->raw_data_swapped); + free(btf->type_offs); free(btf); } -struct btf *btf__new(__u8 *data, __u32 size) +static struct btf *btf_new_empty(struct btf *base_btf) +{ + struct btf *btf; + + btf = calloc(1, sizeof(*btf)); + if (!btf) + return ERR_PTR(-ENOMEM); + + btf->nr_types = 0; + btf->start_id = 1; + btf->start_str_off = 0; + btf->fd = -1; + btf->ptr_sz = sizeof(void *); + btf->swapped_endian = false; + + if (base_btf) { + btf->base_btf = base_btf; + btf->start_id = btf__type_cnt(base_btf); + btf->start_str_off = base_btf->hdr->str_len; + } + + /* +1 for empty string at offset 0 */ + btf->raw_size = sizeof(struct btf_header) + (base_btf ? 0 : 1); + btf->raw_data = calloc(1, btf->raw_size); + if (!btf->raw_data) { + free(btf); + return ERR_PTR(-ENOMEM); + } + + btf->hdr = btf->raw_data; + btf->hdr->hdr_len = sizeof(struct btf_header); + btf->hdr->magic = BTF_MAGIC; + btf->hdr->version = BTF_VERSION; + + btf->types_data = btf->raw_data + btf->hdr->hdr_len; + btf->strs_data = btf->raw_data + btf->hdr->hdr_len; + btf->hdr->str_len = base_btf ? 0 : 1; /* empty string at offset 0 */ + + return btf; +} + +struct btf *btf__new_empty(void) +{ + return libbpf_ptr(btf_new_empty(NULL)); +} + +struct btf *btf__new_empty_split(struct btf *base_btf) +{ + return libbpf_ptr(btf_new_empty(base_btf)); +} + +static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf) { struct btf *btf; int err; @@ -406,27 +860,38 @@ struct btf *btf__new(__u8 *data, __u32 size) if (!btf) return ERR_PTR(-ENOMEM); + btf->nr_types = 0; + btf->start_id = 1; + btf->start_str_off = 0; btf->fd = -1; - btf->data = malloc(size); - if (!btf->data) { + if (base_btf) { + btf->base_btf = base_btf; + btf->start_id = btf__type_cnt(base_btf); + btf->start_str_off = base_btf->hdr->str_len; + } + + btf->raw_data = malloc(size); + if (!btf->raw_data) { err = -ENOMEM; goto done; } + memcpy(btf->raw_data, data, size); + btf->raw_size = size; - memcpy(btf->data, data, size); - btf->data_size = size; - + btf->hdr = btf->raw_data; err = btf_parse_hdr(btf); if (err) goto done; + btf->strs_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->str_off; + btf->types_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->type_off; + err = btf_parse_str_sec(btf); + err = err ?: btf_parse_type_sec(btf); if (err) goto done; - err = btf_parse_type_sec(btf); - done: if (err) { btf__free(btf); @@ -436,18 +901,13 @@ done: return btf; } -static bool btf_check_endianness(const GElf_Ehdr *ehdr) +struct btf *btf__new(const void *data, __u32 size) { -#if __BYTE_ORDER == __LITTLE_ENDIAN - return ehdr->e_ident[EI_DATA] == ELFDATA2LSB; -#elif __BYTE_ORDER == __BIG_ENDIAN - return ehdr->e_ident[EI_DATA] == ELFDATA2MSB; -#else -# error "Unrecognized __BYTE_ORDER__" -#endif + return libbpf_ptr(btf_new(data, size, NULL)); } -struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) +static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, + struct btf_ext **btf_ext) { Elf_Data *btf_data = NULL, *btf_ext_data = NULL; int err = 0, fd = -1, idx = 0; @@ -455,13 +915,14 @@ struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) Elf_Scn *scn = NULL; Elf *elf = NULL; GElf_Ehdr ehdr; + size_t shstrndx; if (elf_version(EV_CURRENT) == EV_NONE) { pr_warn("failed to init libelf for %s\n", path); return ERR_PTR(-LIBBPF_ERRNO__LIBELF); } - fd = open(path, O_RDONLY); + fd = open(path, O_RDONLY | O_CLOEXEC); if (fd < 0) { err = -errno; pr_warn("failed to open %s: %s\n", path, strerror(errno)); @@ -479,11 +940,14 @@ struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) pr_warn("failed to get EHDR from %s\n", path); goto done; } - if (!btf_check_endianness(&ehdr)) { - pr_warn("non-native ELF endianness is not supported\n"); + + if (elf_getshdrstrndx(elf, &shstrndx)) { + pr_warn("failed to get section names section index for %s\n", + path); goto done; } - if (!elf_rawdata(elf_getscn(elf, ehdr.e_shstrndx), NULL)) { + + if (!elf_rawdata(elf_getscn(elf, shstrndx), NULL)) { pr_warn("failed to get e_shstrndx from %s\n", path); goto done; } @@ -498,7 +962,7 @@ struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) idx, path); goto done; } - name = elf_strptr(elf, ehdr.e_shstrndx, sh.sh_name); + name = elf_strptr(elf, shstrndx, sh.sh_name); if (!name) { pr_warn("failed to get section(%d) name from %s\n", idx, path); @@ -529,14 +993,27 @@ struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) err = -ENOENT; goto done; } - btf = btf__new(btf_data->d_buf, btf_data->d_size); - if (IS_ERR(btf)) + btf = btf_new(btf_data->d_buf, btf_data->d_size, base_btf); + err = libbpf_get_error(btf); + if (err) goto done; + switch (gelf_getclass(elf)) { + case ELFCLASS32: + btf__set_pointer_size(btf, 4); + break; + case ELFCLASS64: + btf__set_pointer_size(btf, 8); + break; + default: + pr_warn("failed to get ELF class (bitness) for %s\n", path); + break; + } + if (btf_ext && btf_ext_data) { - *btf_ext = btf_ext__new(btf_ext_data->d_buf, - btf_ext_data->d_size); - if (IS_ERR(*btf_ext)) + *btf_ext = btf_ext__new(btf_ext_data->d_buf, btf_ext_data->d_size); + err = libbpf_get_error(*btf_ext); + if (err) goto done; } else if (btf_ext) { *btf_ext = NULL; @@ -546,143 +1023,206 @@ done: elf_end(elf); close(fd); - if (err) - return ERR_PTR(err); - /* - * btf is always parsed before btf_ext, so no need to clean up - * btf_ext, if btf loading failed - */ - if (IS_ERR(btf)) + if (!err) return btf; - if (btf_ext && IS_ERR(*btf_ext)) { - btf__free(btf); - err = PTR_ERR(*btf_ext); - return ERR_PTR(err); - } - return btf; + + if (btf_ext) + btf_ext__free(*btf_ext); + btf__free(btf); + + return ERR_PTR(err); } -static int compare_vsi_off(const void *_a, const void *_b) +struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) { - const struct btf_var_secinfo *a = _a; - const struct btf_var_secinfo *b = _b; + return libbpf_ptr(btf_parse_elf(path, NULL, btf_ext)); +} - return a->offset - b->offset; +struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf) +{ + return libbpf_ptr(btf_parse_elf(path, base_btf, NULL)); } -static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf, - struct btf_type *t) +static struct btf *btf_parse_raw(const char *path, struct btf *base_btf) { - __u32 size = 0, off = 0, i, vars = btf_vlen(t); - const char *name = btf__name_by_offset(btf, t->name_off); - const struct btf_type *t_var; - struct btf_var_secinfo *vsi; - const struct btf_var *var; - int ret; + struct btf *btf = NULL; + void *data = NULL; + FILE *f = NULL; + __u16 magic; + int err = 0; + long sz; - if (!name) { - pr_debug("No name found in string section for DATASEC kind.\n"); - return -ENOENT; + f = fopen(path, "rb"); + if (!f) { + err = -errno; + goto err_out; } - /* .extern datasec size and var offsets were set correctly during - * extern collection step, so just skip straight to sorting variables - */ - if (t->size) - goto sort_vars; + /* check BTF magic */ + if (fread(&magic, 1, sizeof(magic), f) < sizeof(magic)) { + err = -EIO; + goto err_out; + } + if (magic != BTF_MAGIC && magic != bswap_16(BTF_MAGIC)) { + /* definitely not a raw BTF */ + err = -EPROTO; + goto err_out; + } - ret = bpf_object__section_size(obj, name, &size); - if (ret || !size || (t->size && t->size != size)) { - pr_debug("Invalid size for section %s: %u bytes\n", name, size); - return -ENOENT; + /* get file size */ + if (fseek(f, 0, SEEK_END)) { + err = -errno; + goto err_out; + } + sz = ftell(f); + if (sz < 0) { + err = -errno; + goto err_out; + } + /* rewind to the start */ + if (fseek(f, 0, SEEK_SET)) { + err = -errno; + goto err_out; } - t->size = size; + /* pre-alloc memory and read all of BTF data */ + data = malloc(sz); + if (!data) { + err = -ENOMEM; + goto err_out; + } + if (fread(data, 1, sz, f) < sz) { + err = -EIO; + goto err_out; + } - for (i = 0, vsi = btf_var_secinfos(t); i < vars; i++, vsi++) { - t_var = btf__type_by_id(btf, vsi->type); - var = btf_var(t_var); + /* finally parse BTF data */ + btf = btf_new(data, sz, base_btf); - if (!btf_is_var(t_var)) { - pr_debug("Non-VAR type seen in section %s\n", name); - return -EINVAL; - } +err_out: + free(data); + if (f) + fclose(f); + return err ? ERR_PTR(err) : btf; +} - if (var->linkage == BTF_VAR_STATIC) - continue; +struct btf *btf__parse_raw(const char *path) +{ + return libbpf_ptr(btf_parse_raw(path, NULL)); +} - name = btf__name_by_offset(btf, t_var->name_off); - if (!name) { - pr_debug("No name found in string section for VAR kind\n"); - return -ENOENT; - } +struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf) +{ + return libbpf_ptr(btf_parse_raw(path, base_btf)); +} - ret = bpf_object__variable_offset(obj, name, &off); - if (ret) { - pr_debug("No offset found in symbol table for VAR %s\n", - name); - return -ENOENT; - } +static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ext **btf_ext) +{ + struct btf *btf; + int err; - vsi->offset = off; - } + if (btf_ext) + *btf_ext = NULL; -sort_vars: - qsort(btf_var_secinfos(t), vars, sizeof(*vsi), compare_vsi_off); - return 0; + btf = btf_parse_raw(path, base_btf); + err = libbpf_get_error(btf); + if (!err) + return btf; + if (err != -EPROTO) + return ERR_PTR(err); + return btf_parse_elf(path, base_btf, btf_ext); } -int btf__finalize_data(struct bpf_object *obj, struct btf *btf) +struct btf *btf__parse(const char *path, struct btf_ext **btf_ext) { - int err = 0; - __u32 i; - - for (i = 1; i <= btf->nr_types; i++) { - struct btf_type *t = btf->types[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, btf, t); - if (err) - break; - } - } + return libbpf_ptr(btf_parse(path, NULL, btf_ext)); +} - return err; +struct btf *btf__parse_split(const char *path, struct btf *base_btf) +{ + return libbpf_ptr(btf_parse(path, base_btf, NULL)); } -int btf__load(struct btf *btf) +static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian); + +int btf_load_into_kernel(struct btf *btf, char *log_buf, size_t log_sz, __u32 log_level) { - __u32 log_buf_size = BPF_LOG_BUF_SIZE; - char *log_buf = NULL; + LIBBPF_OPTS(bpf_btf_load_opts, opts); + __u32 buf_sz = 0, raw_size; + char *buf = NULL, *tmp; + void *raw_data; int err = 0; if (btf->fd >= 0) - return -EEXIST; + return libbpf_err(-EEXIST); + if (log_sz && !log_buf) + return libbpf_err(-EINVAL); - log_buf = malloc(log_buf_size); - if (!log_buf) - return -ENOMEM; + /* cache native raw data representation */ + raw_data = btf_get_raw_data(btf, &raw_size, false); + if (!raw_data) { + err = -ENOMEM; + goto done; + } + btf->raw_size = raw_size; + btf->raw_data = raw_data; + +retry_load: + /* if log_level is 0, we won't provide log_buf/log_size to the kernel, + * initially. Only if BTF loading fails, we bump log_level to 1 and + * retry, using either auto-allocated or custom log_buf. This way + * non-NULL custom log_buf provides a buffer just in case, but hopes + * for successful load and no need for log_buf. + */ + if (log_level) { + /* if caller didn't provide custom log_buf, we'll keep + * allocating our own progressively bigger buffers for BTF + * verification log + */ + if (!log_buf) { + buf_sz = max((__u32)BPF_LOG_BUF_SIZE, buf_sz * 2); + tmp = realloc(buf, buf_sz); + if (!tmp) { + err = -ENOMEM; + goto done; + } + buf = tmp; + buf[0] = '\0'; + } - *log_buf = 0; + opts.log_buf = log_buf ? log_buf : buf; + opts.log_size = log_buf ? log_sz : buf_sz; + opts.log_level = log_level; + } - btf->fd = bpf_load_btf(btf->data, btf->data_size, - log_buf, log_buf_size, false); + btf->fd = bpf_btf_load(raw_data, raw_size, &opts); if (btf->fd < 0) { + /* time to turn on verbose mode and try again */ + if (log_level == 0) { + log_level = 1; + goto retry_load; + } + /* only retry if caller didn't provide custom log_buf, but + * make sure we can never overflow buf_sz + */ + if (!log_buf && errno == ENOSPC && buf_sz <= UINT_MAX / 2) + goto retry_load; + err = -errno; - pr_warn("Error loading BTF: %s(%d)\n", strerror(errno), errno); - if (*log_buf) - pr_warn("%s\n", log_buf); - goto done; + pr_warn("BTF loading error: %d\n", err); + /* don't print out contents of custom log_buf */ + if (!log_buf && buf[0]) + pr_warn("-- BEGIN BTF LOAD LOG ---\n%s\n-- END BTF LOAD LOG --\n", buf); } done: - free(log_buf); - return err; + free(buf); + return libbpf_err(err); +} + +int btf__load_into_kernel(struct btf *btf) +{ + return btf_load_into_kernel(btf, NULL, 0, 0); } int btf__fd(const struct btf *btf) @@ -690,49 +1230,124 @@ int btf__fd(const struct btf *btf) return btf->fd; } -const void *btf__get_raw_data(const struct btf *btf, __u32 *size) +void btf__set_fd(struct btf *btf, int fd) { - *size = btf->data_size; - return btf->data; + btf->fd = fd; } -const char *btf__name_by_offset(const struct btf *btf, __u32 offset) +static const void *btf_strs_data(const struct btf *btf) { - if (offset < btf->hdr->str_len) - return &btf->strings[offset]; - else + return btf->strs_data ? btf->strs_data : strset__data(btf->strs_set); +} + +static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian) +{ + struct btf_header *hdr = btf->hdr; + struct btf_type *t; + void *data, *p; + __u32 data_sz; + int i; + + data = swap_endian ? btf->raw_data_swapped : btf->raw_data; + if (data) { + *size = btf->raw_size; + return data; + } + + data_sz = hdr->hdr_len + hdr->type_len + hdr->str_len; + data = calloc(1, data_sz); + if (!data) return NULL; + p = data; + + memcpy(p, hdr, hdr->hdr_len); + if (swap_endian) + btf_bswap_hdr(p); + p += hdr->hdr_len; + + memcpy(p, btf->types_data, hdr->type_len); + if (swap_endian) { + for (i = 0; i < btf->nr_types; i++) { + t = p + btf->type_offs[i]; + /* btf_bswap_type_rest() relies on native t->info, so + * we swap base type info after we swapped all the + * additional information + */ + if (btf_bswap_type_rest(t)) + goto err_out; + btf_bswap_type_base(t); + } + } + p += hdr->type_len; + + memcpy(p, btf_strs_data(btf), hdr->str_len); + p += hdr->str_len; + + *size = data_sz; + return data; +err_out: + free(data); + return NULL; +} + +const void *btf__raw_data(const struct btf *btf_ro, __u32 *size) +{ + struct btf *btf = (struct btf *)btf_ro; + __u32 data_sz; + void *data; + + data = btf_get_raw_data(btf, &data_sz, btf->swapped_endian); + if (!data) + return errno = ENOMEM, NULL; + + btf->raw_size = data_sz; + if (btf->swapped_endian) + btf->raw_data_swapped = data; + else + btf->raw_data = data; + *size = data_sz; + return data; } -int btf__get_from_id(__u32 id, struct btf **btf) +__attribute__((alias("btf__raw_data"))) +const void *btf__get_raw_data(const struct btf *btf, __u32 *size); + +const char *btf__str_by_offset(const struct btf *btf, __u32 offset) { - struct bpf_btf_info btf_info = { 0 }; + if (offset < btf->start_str_off) + return btf__str_by_offset(btf->base_btf, offset); + else if (offset - btf->start_str_off < btf->hdr->str_len) + return btf_strs_data(btf) + (offset - btf->start_str_off); + else + return errno = EINVAL, NULL; +} + +const char *btf__name_by_offset(const struct btf *btf, __u32 offset) +{ + return btf__str_by_offset(btf, offset); +} + +struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf) +{ + struct bpf_btf_info btf_info; __u32 len = sizeof(btf_info); __u32 last_size; - int btf_fd; + struct btf *btf; void *ptr; int err; - err = 0; - *btf = NULL; - btf_fd = bpf_btf_get_fd_by_id(id); - if (btf_fd < 0) - return 0; - /* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so * let's start with a sane default - 4KiB here - and resize it only if * bpf_obj_get_info_by_fd() needs a bigger buffer. */ - btf_info.btf_size = 4096; - last_size = btf_info.btf_size; + last_size = 4096; ptr = malloc(last_size); - if (!ptr) { - err = -ENOMEM; - goto exit_free; - } + if (!ptr) + return ERR_PTR(-ENOMEM); - memset(ptr, 0, last_size); + memset(&btf_info, 0, sizeof(btf_info)); btf_info.btf = ptr_to_u64(ptr); + btf_info.btf_size = last_size; err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len); if (!err && btf_info.btf_size > last_size) { @@ -741,104 +1356,1281 @@ int btf__get_from_id(__u32 id, struct btf **btf) last_size = btf_info.btf_size; temp_ptr = realloc(ptr, last_size); if (!temp_ptr) { - err = -ENOMEM; + btf = ERR_PTR(-ENOMEM); goto exit_free; } ptr = temp_ptr; - memset(ptr, 0, last_size); + + len = sizeof(btf_info); + memset(&btf_info, 0, sizeof(btf_info)); btf_info.btf = ptr_to_u64(ptr); + btf_info.btf_size = last_size; + err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len); } if (err || btf_info.btf_size > last_size) { - err = errno; + btf = err ? ERR_PTR(-errno) : ERR_PTR(-E2BIG); goto exit_free; } - *btf = btf__new((__u8 *)(long)btf_info.btf, btf_info.btf_size); - if (IS_ERR(*btf)) { - err = PTR_ERR(*btf); - *btf = NULL; - } + btf = btf_new(ptr, btf_info.btf_size, base_btf); exit_free: - close(btf_fd); free(ptr); + return btf; +} + +struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf) +{ + struct btf *btf; + int btf_fd; + + btf_fd = bpf_btf_get_fd_by_id(id); + if (btf_fd < 0) + return libbpf_err_ptr(-errno); + btf = btf_get_from_fd(btf_fd, base_btf); + close(btf_fd); + + return libbpf_ptr(btf); +} + +struct btf *btf__load_from_kernel_by_id(__u32 id) +{ + return btf__load_from_kernel_by_id_split(id, NULL); +} + +static void btf_invalidate_raw_data(struct btf *btf) +{ + if (btf->raw_data) { + free(btf->raw_data); + btf->raw_data = NULL; + } + if (btf->raw_data_swapped) { + free(btf->raw_data_swapped); + btf->raw_data_swapped = NULL; + } +} + +/* Ensure BTF is ready to be modified (by splitting into a three memory + * regions for header, types, and strings). Also invalidate cached + * raw_data, if any. + */ +static int btf_ensure_modifiable(struct btf *btf) +{ + void *hdr, *types; + struct strset *set = NULL; + int err = -ENOMEM; + + if (btf_is_modifiable(btf)) { + /* any BTF modification invalidates raw_data */ + btf_invalidate_raw_data(btf); + return 0; + } + + /* split raw data into three memory regions */ + hdr = malloc(btf->hdr->hdr_len); + types = malloc(btf->hdr->type_len); + if (!hdr || !types) + goto err_out; + + memcpy(hdr, btf->hdr, btf->hdr->hdr_len); + memcpy(types, btf->types_data, btf->hdr->type_len); + + /* build lookup index for all strings */ + set = strset__new(BTF_MAX_STR_OFFSET, btf->strs_data, btf->hdr->str_len); + if (IS_ERR(set)) { + err = PTR_ERR(set); + goto err_out; + } + + /* only when everything was successful, update internal state */ + btf->hdr = hdr; + btf->types_data = types; + btf->types_data_cap = btf->hdr->type_len; + btf->strs_data = NULL; + btf->strs_set = set; + /* if BTF was created from scratch, all strings are guaranteed to be + * unique and deduplicated + */ + if (btf->hdr->str_len == 0) + btf->strs_deduped = true; + if (!btf->base_btf && btf->hdr->str_len == 1) + btf->strs_deduped = true; + + /* invalidate raw_data representation */ + btf_invalidate_raw_data(btf); + + return 0; + +err_out: + strset__free(set); + free(hdr); + free(types); return err; } -int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, - __u32 expected_key_size, __u32 expected_value_size, - __u32 *key_type_id, __u32 *value_type_id) +/* Find an offset in BTF string section that corresponds to a given string *s*. + * Returns: + * - >0 offset into string section, if string is found; + * - -ENOENT, if string is not in the string section; + * - <0, on any other error. + */ +int btf__find_str(struct btf *btf, const char *s) { - const struct btf_type *container_type; - const struct btf_member *key, *value; - const size_t max_name = 256; - char container_name[max_name]; - __s64 key_size, value_size; - __s32 container_id; + int off; - if (snprintf(container_name, max_name, "____btf_map_%s", map_name) == - max_name) { - pr_warn("map:%s length of '____btf_map_%s' is too long\n", - map_name, map_name); - return -EINVAL; + if (btf->base_btf) { + off = btf__find_str(btf->base_btf, s); + if (off != -ENOENT) + return off; } - 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; + /* BTF needs to be in a modifiable state to build string lookup index */ + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + off = strset__find_str(btf->strs_set, s); + if (off < 0) + return libbpf_err(off); + + return btf->start_str_off + off; +} + +/* Add a string s to the BTF string section. + * Returns: + * - > 0 offset into string section, on success; + * - < 0, on error. + */ +int btf__add_str(struct btf *btf, const char *s) +{ + int off; + + if (btf->base_btf) { + off = btf__find_str(btf->base_btf, s); + if (off != -ENOENT) + return off; } - container_type = btf__type_by_id(btf, container_id); - if (!container_type) { - pr_warn("map:%s cannot find BTF type for container_id:%u\n", - map_name, container_id); - return -EINVAL; + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + off = strset__add_str(btf->strs_set, s); + if (off < 0) + return libbpf_err(off); + + btf->hdr->str_len = strset__data_size(btf->strs_set); + + return btf->start_str_off + off; +} + +static void *btf_add_type_mem(struct btf *btf, size_t add_sz) +{ + return libbpf_add_mem(&btf->types_data, &btf->types_data_cap, 1, + btf->hdr->type_len, UINT_MAX, add_sz); +} + +static void btf_type_inc_vlen(struct btf_type *t) +{ + t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, btf_kflag(t)); +} + +static int btf_commit_type(struct btf *btf, int data_sz) +{ + int err; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return libbpf_err(err); + + btf->hdr->type_len += data_sz; + btf->hdr->str_off += data_sz; + btf->nr_types++; + return btf->start_id + btf->nr_types - 1; +} + +struct btf_pipe { + const struct btf *src; + struct btf *dst; + struct hashmap *str_off_map; /* map string offsets from src to dst */ +}; + +static int btf_rewrite_str(__u32 *str_off, void *ctx) +{ + struct btf_pipe *p = ctx; + void *mapped_off; + int off, err; + + if (!*str_off) /* nothing to do for empty strings */ + return 0; + + if (p->str_off_map && + hashmap__find(p->str_off_map, (void *)(long)*str_off, &mapped_off)) { + *str_off = (__u32)(long)mapped_off; + return 0; } - if (!btf_is_struct(container_type) || btf_vlen(container_type) < 2) { - pr_warn("map:%s container_name:%s is an invalid container struct\n", - map_name, container_name); - return -EINVAL; + off = btf__add_str(p->dst, btf__str_by_offset(p->src, *str_off)); + if (off < 0) + return off; + + /* Remember string mapping from src to dst. It avoids + * performing expensive string comparisons. + */ + if (p->str_off_map) { + err = hashmap__append(p->str_off_map, (void *)(long)*str_off, (void *)(long)off); + if (err) + return err; } - key = btf_members(container_type); - value = key + 1; + *str_off = off; + return 0; +} + +int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type) +{ + struct btf_pipe p = { .src = src_btf, .dst = btf }; + struct btf_type *t; + int sz, err; - key_size = btf__resolve_size(btf, key->type); - if (key_size < 0) { - pr_warn("map:%s invalid BTF key_type_size\n", map_name); - return key_size; + sz = btf_type_size(src_type); + if (sz < 0) + return libbpf_err(sz); + + /* deconstruct BTF, if necessary, and invalidate raw_data */ + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + memcpy(t, src_type, sz); + + err = btf_type_visit_str_offs(t, btf_rewrite_str, &p); + if (err) + return libbpf_err(err); + + return btf_commit_type(btf, sz); +} + +static int btf_rewrite_type_ids(__u32 *type_id, void *ctx) +{ + struct btf *btf = ctx; + + if (!*type_id) /* nothing to do for VOID references */ + return 0; + + /* we haven't updated btf's type count yet, so + * btf->start_id + btf->nr_types - 1 is the type ID offset we should + * add to all newly added BTF types + */ + *type_id += btf->start_id + btf->nr_types - 1; + return 0; +} + +static size_t btf_dedup_identity_hash_fn(const void *key, void *ctx); +static bool btf_dedup_equal_fn(const void *k1, const void *k2, void *ctx); + +int btf__add_btf(struct btf *btf, const struct btf *src_btf) +{ + struct btf_pipe p = { .src = src_btf, .dst = btf }; + int data_sz, sz, cnt, i, err, old_strs_len; + __u32 *off; + void *t; + + /* appending split BTF isn't supported yet */ + if (src_btf->base_btf) + return libbpf_err(-ENOTSUP); + + /* deconstruct BTF, if necessary, and invalidate raw_data */ + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + /* remember original strings section size if we have to roll back + * partial strings section changes + */ + old_strs_len = btf->hdr->str_len; + + data_sz = src_btf->hdr->type_len; + cnt = btf__type_cnt(src_btf) - 1; + + /* pre-allocate enough memory for new types */ + t = btf_add_type_mem(btf, data_sz); + if (!t) + return libbpf_err(-ENOMEM); + + /* pre-allocate enough memory for type offset index for new types */ + off = btf_add_type_offs_mem(btf, cnt); + if (!off) + return libbpf_err(-ENOMEM); + + /* Map the string offsets from src_btf to the offsets from btf to improve performance */ + p.str_off_map = hashmap__new(btf_dedup_identity_hash_fn, btf_dedup_equal_fn, NULL); + if (IS_ERR(p.str_off_map)) + return libbpf_err(-ENOMEM); + + /* bulk copy types data for all types from src_btf */ + memcpy(t, src_btf->types_data, data_sz); + + for (i = 0; i < cnt; i++) { + sz = btf_type_size(t); + if (sz < 0) { + /* unlikely, has to be corrupted src_btf */ + err = sz; + goto err_out; + } + + /* fill out type ID to type offset mapping for lookups by type ID */ + *off = t - btf->types_data; + + /* add, dedup, and remap strings referenced by this BTF type */ + err = btf_type_visit_str_offs(t, btf_rewrite_str, &p); + if (err) + goto err_out; + + /* remap all type IDs referenced from this BTF type */ + err = btf_type_visit_type_ids(t, btf_rewrite_type_ids, btf); + if (err) + goto err_out; + + /* go to next type data and type offset index entry */ + t += sz; + off++; } - if (expected_key_size != key_size) { - pr_warn("map:%s btf_key_type_size:%u != map_def_key_size:%u\n", - map_name, (__u32)key_size, expected_key_size); + /* Up until now any of the copied type data was effectively invisible, + * so if we exited early before this point due to error, BTF would be + * effectively unmodified. There would be extra internal memory + * pre-allocated, but it would not be available for querying. But now + * that we've copied and rewritten all the data successfully, we can + * update type count and various internal offsets and sizes to + * "commit" the changes and made them visible to the outside world. + */ + btf->hdr->type_len += data_sz; + btf->hdr->str_off += data_sz; + btf->nr_types += cnt; + + hashmap__free(p.str_off_map); + + /* return type ID of the first added BTF type */ + return btf->start_id + btf->nr_types - cnt; +err_out: + /* zero out preallocated memory as if it was just allocated with + * libbpf_add_mem() + */ + memset(btf->types_data + btf->hdr->type_len, 0, data_sz); + memset(btf->strs_data + old_strs_len, 0, btf->hdr->str_len - old_strs_len); + + /* and now restore original strings section size; types data size + * wasn't modified, so doesn't need restoring, see big comment above */ + btf->hdr->str_len = old_strs_len; + + hashmap__free(p.str_off_map); + + return libbpf_err(err); +} + +/* + * Append new BTF_KIND_INT type with: + * - *name* - non-empty, non-NULL type name; + * - *sz* - power-of-2 (1, 2, 4, ..) size of the type, in bytes; + * - encoding is a combination of BTF_INT_SIGNED, BTF_INT_CHAR, BTF_INT_BOOL. + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding) +{ + struct btf_type *t; + int sz, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return libbpf_err(-EINVAL); + /* byte_sz must be power of 2 */ + if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 16) + return libbpf_err(-EINVAL); + if (encoding & ~(BTF_INT_SIGNED | BTF_INT_CHAR | BTF_INT_BOOL)) + return libbpf_err(-EINVAL); + + /* deconstruct BTF, if necessary, and invalidate raw_data */ + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_type) + sizeof(int); + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + /* if something goes wrong later, we might end up with an extra string, + * but that shouldn't be a problem, because BTF can't be constructed + * completely anyway and will most probably be just discarded + */ + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_INT, 0, 0); + t->size = byte_sz; + /* set INT info, we don't allow setting legacy bit offset/size */ + *(__u32 *)(t + 1) = (encoding << 24) | (byte_sz * 8); + + return btf_commit_type(btf, sz); +} + +/* + * Append new BTF_KIND_FLOAT type with: + * - *name* - non-empty, non-NULL type name; + * - *sz* - size of the type, in bytes; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_float(struct btf *btf, const char *name, size_t byte_sz) +{ + struct btf_type *t; + int sz, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return libbpf_err(-EINVAL); + + /* byte_sz must be one of the explicitly allowed values */ + if (byte_sz != 2 && byte_sz != 4 && byte_sz != 8 && byte_sz != 12 && + byte_sz != 16) + return libbpf_err(-EINVAL); + + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_FLOAT, 0, 0); + t->size = byte_sz; + + return btf_commit_type(btf, sz); +} + +/* it's completely legal to append BTF types with type IDs pointing forward to + * types that haven't been appended yet, so we only make sure that id looks + * sane, we can't guarantee that ID will always be valid + */ +static int validate_type_id(int id) +{ + if (id < 0 || id > BTF_MAX_NR_TYPES) return -EINVAL; + return 0; +} + +/* generic append function for PTR, TYPEDEF, CONST/VOLATILE/RESTRICT */ +static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref_type_id) +{ + struct btf_type *t; + int sz, name_off = 0; + + if (validate_type_id(ref_type_id)) + return libbpf_err(-EINVAL); + + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; } - value_size = btf__resolve_size(btf, value->type); - if (value_size < 0) { - pr_warn("map:%s invalid BTF value_type_size\n", map_name); - return value_size; + t->name_off = name_off; + t->info = btf_type_info(kind, 0, 0); + t->type = ref_type_id; + + return btf_commit_type(btf, sz); +} + +/* + * Append new BTF_KIND_PTR type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_ptr(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_PTR, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_ARRAY type with: + * - *index_type_id* - type ID of the type describing array index; + * - *elem_type_id* - type ID of the type describing array element; + * - *nr_elems* - the size of the array; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_array(struct btf *btf, int index_type_id, int elem_type_id, __u32 nr_elems) +{ + struct btf_type *t; + struct btf_array *a; + int sz; + + if (validate_type_id(index_type_id) || validate_type_id(elem_type_id)) + return libbpf_err(-EINVAL); + + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_type) + sizeof(struct btf_array); + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + t->name_off = 0; + t->info = btf_type_info(BTF_KIND_ARRAY, 0, 0); + t->size = 0; + + a = btf_array(t); + a->type = elem_type_id; + a->index_type = index_type_id; + a->nelems = nr_elems; + + return btf_commit_type(btf, sz); +} + +/* generic STRUCT/UNION append function */ +static int btf_add_composite(struct btf *btf, int kind, const char *name, __u32 bytes_sz) +{ + struct btf_type *t; + int sz, name_off = 0; + + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; } - if (expected_value_size != value_size) { - pr_warn("map:%s btf_value_type_size:%u != map_def_value_size:%u\n", - map_name, (__u32)value_size, expected_value_size); - return -EINVAL; + /* start out with vlen=0 and no kflag; this will be adjusted when + * adding each member + */ + t->name_off = name_off; + t->info = btf_type_info(kind, 0, 0); + t->size = bytes_sz; + + return btf_commit_type(btf, sz); +} + +/* + * Append new BTF_KIND_STRUCT type with: + * - *name* - name of the struct, can be NULL or empty for anonymous structs; + * - *byte_sz* - size of the struct, in bytes; + * + * Struct initially has no fields in it. Fields can be added by + * btf__add_field() right after btf__add_struct() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_struct(struct btf *btf, const char *name, __u32 byte_sz) +{ + return btf_add_composite(btf, BTF_KIND_STRUCT, name, byte_sz); +} + +/* + * Append new BTF_KIND_UNION type with: + * - *name* - name of the union, can be NULL or empty for anonymous union; + * - *byte_sz* - size of the union, in bytes; + * + * Union initially has no fields in it. Fields can be added by + * btf__add_field() right after btf__add_union() succeeds. All fields + * should have *bit_offset* of 0. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_union(struct btf *btf, const char *name, __u32 byte_sz) +{ + return btf_add_composite(btf, BTF_KIND_UNION, name, byte_sz); +} + +static struct btf_type *btf_last_type(struct btf *btf) +{ + return btf_type_by_id(btf, btf__type_cnt(btf) - 1); +} + +/* + * Append new field for the current STRUCT/UNION type with: + * - *name* - name of the field, can be NULL or empty for anonymous field; + * - *type_id* - type ID for the type describing field type; + * - *bit_offset* - bit offset of the start of the field within struct/union; + * - *bit_size* - bit size of a bitfield, 0 for non-bitfield fields; + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_field(struct btf *btf, const char *name, int type_id, + __u32 bit_offset, __u32 bit_size) +{ + struct btf_type *t; + struct btf_member *m; + bool is_bitfield; + int sz, name_off = 0; + + /* last type should be union/struct */ + if (btf->nr_types == 0) + return libbpf_err(-EINVAL); + t = btf_last_type(btf); + if (!btf_is_composite(t)) + return libbpf_err(-EINVAL); + + if (validate_type_id(type_id)) + return libbpf_err(-EINVAL); + /* best-effort bit field offset/size enforcement */ + is_bitfield = bit_size || (bit_offset % 8 != 0); + if (is_bitfield && (bit_size == 0 || bit_size > 255 || bit_offset > 0xffffff)) + return libbpf_err(-EINVAL); + + /* only offset 0 is allowed for unions */ + if (btf_is_union(t) && bit_offset) + return libbpf_err(-EINVAL); + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_member); + m = btf_add_type_mem(btf, sz); + if (!m) + return libbpf_err(-ENOMEM); + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; } - *key_type_id = key->type; - *value_type_id = value->type; + m->name_off = name_off; + m->type = type_id; + m->offset = bit_offset | (bit_size << 24); + /* btf_add_type_mem can invalidate t pointer */ + t = btf_last_type(btf); + /* update parent type's vlen and kflag */ + t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, is_bitfield || btf_kflag(t)); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; return 0; } +static int btf_add_enum_common(struct btf *btf, const char *name, __u32 byte_sz, + bool is_signed, __u8 kind) +{ + struct btf_type *t; + int sz, name_off = 0; + + /* byte_sz must be power of 2 */ + if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 8) + return libbpf_err(-EINVAL); + + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + /* start out with vlen=0; it will be adjusted when adding enum values */ + t->name_off = name_off; + t->info = btf_type_info(kind, 0, is_signed); + t->size = byte_sz; + + return btf_commit_type(btf, sz); +} + +/* + * Append new BTF_KIND_ENUM type with: + * - *name* - name of the enum, can be NULL or empty for anonymous enums; + * - *byte_sz* - size of the enum, in bytes. + * + * Enum initially has no enum values in it (and corresponds to enum forward + * declaration). Enumerator values can be added by btf__add_enum_value() + * immediately after btf__add_enum() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_enum(struct btf *btf, const char *name, __u32 byte_sz) +{ + /* + * set the signedness to be unsigned, it will change to signed + * if any later enumerator is negative. + */ + return btf_add_enum_common(btf, name, byte_sz, false, BTF_KIND_ENUM); +} + +/* + * Append new enum value for the current ENUM type with: + * - *name* - name of the enumerator value, can't be NULL or empty; + * - *value* - integer value corresponding to enum value *name*; + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_enum_value(struct btf *btf, const char *name, __s64 value) +{ + struct btf_type *t; + struct btf_enum *v; + int sz, name_off; + + /* last type should be BTF_KIND_ENUM */ + if (btf->nr_types == 0) + return libbpf_err(-EINVAL); + t = btf_last_type(btf); + if (!btf_is_enum(t)) + return libbpf_err(-EINVAL); + + /* non-empty name */ + if (!name || !name[0]) + return libbpf_err(-EINVAL); + if (value < INT_MIN || value > UINT_MAX) + return libbpf_err(-E2BIG); + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_enum); + v = btf_add_type_mem(btf, sz); + if (!v) + return libbpf_err(-ENOMEM); + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + v->name_off = name_off; + v->val = value; + + /* update parent type's vlen */ + t = btf_last_type(btf); + btf_type_inc_vlen(t); + + /* if negative value, set signedness to signed */ + if (value < 0) + t->info = btf_type_info(btf_kind(t), btf_vlen(t), true); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_ENUM64 type with: + * - *name* - name of the enum, can be NULL or empty for anonymous enums; + * - *byte_sz* - size of the enum, in bytes. + * - *is_signed* - whether the enum values are signed or not; + * + * Enum initially has no enum values in it (and corresponds to enum forward + * declaration). Enumerator values can be added by btf__add_enum64_value() + * immediately after btf__add_enum64() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_enum64(struct btf *btf, const char *name, __u32 byte_sz, + bool is_signed) +{ + return btf_add_enum_common(btf, name, byte_sz, is_signed, + BTF_KIND_ENUM64); +} + +/* + * Append new enum value for the current ENUM64 type with: + * - *name* - name of the enumerator value, can't be NULL or empty; + * - *value* - integer value corresponding to enum value *name*; + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value) +{ + struct btf_enum64 *v; + struct btf_type *t; + int sz, name_off; + + /* last type should be BTF_KIND_ENUM64 */ + if (btf->nr_types == 0) + return libbpf_err(-EINVAL); + t = btf_last_type(btf); + if (!btf_is_enum64(t)) + return libbpf_err(-EINVAL); + + /* non-empty name */ + if (!name || !name[0]) + return libbpf_err(-EINVAL); + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_enum64); + v = btf_add_type_mem(btf, sz); + if (!v) + return libbpf_err(-ENOMEM); + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + v->name_off = name_off; + v->val_lo32 = (__u32)value; + v->val_hi32 = value >> 32; + + /* update parent type's vlen */ + t = btf_last_type(btf); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_FWD type with: + * - *name*, non-empty/non-NULL name; + * - *fwd_kind*, kind of forward declaration, one of BTF_FWD_STRUCT, + * BTF_FWD_UNION, or BTF_FWD_ENUM; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind) +{ + if (!name || !name[0]) + return libbpf_err(-EINVAL); + + switch (fwd_kind) { + case BTF_FWD_STRUCT: + case BTF_FWD_UNION: { + struct btf_type *t; + int id; + + id = btf_add_ref_kind(btf, BTF_KIND_FWD, name, 0); + if (id <= 0) + return id; + t = btf_type_by_id(btf, id); + t->info = btf_type_info(BTF_KIND_FWD, 0, fwd_kind == BTF_FWD_UNION); + return id; + } + case BTF_FWD_ENUM: + /* enum forward in BTF currently is just an enum with no enum + * values; we also assume a standard 4-byte size for it + */ + return btf__add_enum(btf, name, sizeof(int)); + default: + return libbpf_err(-EINVAL); + } +} + +/* + * Append new BTF_KING_TYPEDEF type with: + * - *name*, non-empty/non-NULL name; + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id) +{ + if (!name || !name[0]) + return libbpf_err(-EINVAL); + + return btf_add_ref_kind(btf, BTF_KIND_TYPEDEF, name, ref_type_id); +} + +/* + * Append new BTF_KIND_VOLATILE type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_volatile(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_VOLATILE, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_CONST type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_const(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_CONST, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_RESTRICT type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_restrict(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_RESTRICT, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_TYPE_TAG type with: + * - *value*, non-empty/non-NULL tag value; + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id) +{ + if (!value|| !value[0]) + return libbpf_err(-EINVAL); + + return btf_add_ref_kind(btf, BTF_KIND_TYPE_TAG, value, ref_type_id); +} + +/* + * Append new BTF_KIND_FUNC type with: + * - *name*, non-empty/non-NULL name; + * - *proto_type_id* - FUNC_PROTO's type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_func(struct btf *btf, const char *name, + enum btf_func_linkage linkage, int proto_type_id) +{ + int id; + + if (!name || !name[0]) + return libbpf_err(-EINVAL); + if (linkage != BTF_FUNC_STATIC && linkage != BTF_FUNC_GLOBAL && + linkage != BTF_FUNC_EXTERN) + return libbpf_err(-EINVAL); + + id = btf_add_ref_kind(btf, BTF_KIND_FUNC, name, proto_type_id); + if (id > 0) { + struct btf_type *t = btf_type_by_id(btf, id); + + t->info = btf_type_info(BTF_KIND_FUNC, linkage, 0); + } + return libbpf_err(id); +} + +/* + * Append new BTF_KIND_FUNC_PROTO with: + * - *ret_type_id* - type ID for return result of a function. + * + * Function prototype initially has no arguments, but they can be added by + * btf__add_func_param() one by one, immediately after + * btf__add_func_proto() succeeded. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_func_proto(struct btf *btf, int ret_type_id) +{ + struct btf_type *t; + int sz; + + if (validate_type_id(ret_type_id)) + return libbpf_err(-EINVAL); + + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + /* start out with vlen=0; this will be adjusted when adding enum + * values, if necessary + */ + t->name_off = 0; + t->info = btf_type_info(BTF_KIND_FUNC_PROTO, 0, 0); + t->type = ret_type_id; + + return btf_commit_type(btf, sz); +} + +/* + * Append new function parameter for current FUNC_PROTO type with: + * - *name* - parameter name, can be NULL or empty; + * - *type_id* - type ID describing the type of the parameter. + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_func_param(struct btf *btf, const char *name, int type_id) +{ + struct btf_type *t; + struct btf_param *p; + int sz, name_off = 0; + + if (validate_type_id(type_id)) + return libbpf_err(-EINVAL); + + /* last type should be BTF_KIND_FUNC_PROTO */ + if (btf->nr_types == 0) + return libbpf_err(-EINVAL); + t = btf_last_type(btf); + if (!btf_is_func_proto(t)) + return libbpf_err(-EINVAL); + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_param); + p = btf_add_type_mem(btf, sz); + if (!p) + return libbpf_err(-ENOMEM); + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + p->name_off = name_off; + p->type = type_id; + + /* update parent type's vlen */ + t = btf_last_type(btf); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_VAR type with: + * - *name* - non-empty/non-NULL name; + * - *linkage* - variable linkage, one of BTF_VAR_STATIC, + * BTF_VAR_GLOBAL_ALLOCATED, or BTF_VAR_GLOBAL_EXTERN; + * - *type_id* - type ID of the type describing the type of the variable. + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id) +{ + struct btf_type *t; + struct btf_var *v; + int sz, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return libbpf_err(-EINVAL); + if (linkage != BTF_VAR_STATIC && linkage != BTF_VAR_GLOBAL_ALLOCATED && + linkage != BTF_VAR_GLOBAL_EXTERN) + return libbpf_err(-EINVAL); + if (validate_type_id(type_id)) + return libbpf_err(-EINVAL); + + /* deconstruct BTF, if necessary, and invalidate raw_data */ + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_type) + sizeof(struct btf_var); + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_VAR, 0, 0); + t->type = type_id; + + v = btf_var(t); + v->linkage = linkage; + + return btf_commit_type(btf, sz); +} + +/* + * Append new BTF_KIND_DATASEC type with: + * - *name* - non-empty/non-NULL name; + * - *byte_sz* - data section size, in bytes. + * + * Data section is initially empty. Variables info can be added with + * btf__add_datasec_var_info() calls, after btf__add_datasec() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz) +{ + struct btf_type *t; + int sz, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return libbpf_err(-EINVAL); + + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + /* start with vlen=0, which will be update as var_secinfos are added */ + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_DATASEC, 0, 0); + t->size = byte_sz; + + return btf_commit_type(btf, sz); +} + +/* + * Append new data section variable information entry for current DATASEC type: + * - *var_type_id* - type ID, describing type of the variable; + * - *offset* - variable offset within data section, in bytes; + * - *byte_sz* - variable size, in bytes. + * + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __u32 byte_sz) +{ + struct btf_type *t; + struct btf_var_secinfo *v; + int sz; + + /* last type should be BTF_KIND_DATASEC */ + if (btf->nr_types == 0) + return libbpf_err(-EINVAL); + t = btf_last_type(btf); + if (!btf_is_datasec(t)) + return libbpf_err(-EINVAL); + + if (validate_type_id(var_type_id)) + return libbpf_err(-EINVAL); + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_var_secinfo); + v = btf_add_type_mem(btf, sz); + if (!v) + return libbpf_err(-ENOMEM); + + v->type = var_type_id; + v->offset = offset; + v->size = byte_sz; + + /* update parent type's vlen */ + t = btf_last_type(btf); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_DECL_TAG type with: + * - *value* - non-empty/non-NULL string; + * - *ref_type_id* - referenced type ID, it might not exist yet; + * - *component_idx* - -1 for tagging reference type, otherwise struct/union + * member or function argument index; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id, + int component_idx) +{ + struct btf_type *t; + int sz, value_off; + + if (!value || !value[0] || component_idx < -1) + return libbpf_err(-EINVAL); + + if (validate_type_id(ref_type_id)) + return libbpf_err(-EINVAL); + + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_type) + sizeof(struct btf_decl_tag); + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + value_off = btf__add_str(btf, value); + if (value_off < 0) + return value_off; + + t->name_off = value_off; + t->info = btf_type_info(BTF_KIND_DECL_TAG, 0, false); + t->type = ref_type_id; + btf_decl_tag(t)->component_idx = component_idx; + + return btf_commit_type(btf, sz); +} + struct btf_ext_sec_setup_param { __u32 off; __u32 len; @@ -853,6 +2645,7 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext, const struct btf_ext_info_sec *sinfo; struct btf_ext_info *ext_info; __u32 info_left, record_size; + size_t sec_cnt = 0; /* The start of the info sec (including the __u32 record_size). */ void *info; @@ -916,8 +2709,7 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext, return -EINVAL; } - total_record_size = sec_hdrlen + - (__u64)num_records * record_size; + total_record_size = sec_hdrlen + (__u64)num_records * record_size; if (info_left < total_record_size) { pr_debug("%s section has incorrect num_records in .BTF.ext\n", ext_sec->desc); @@ -926,12 +2718,14 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext, info_left -= total_record_size; sinfo = (void *)sinfo + total_record_size; + sec_cnt++; } ext_info = ext_sec->ext_info; ext_info->len = ext_sec->len - sizeof(__u32); ext_info->rec_size = record_size; ext_info->info = info + sizeof(__u32); + ext_info->sec_cnt = sec_cnt; return 0; } @@ -962,14 +2756,14 @@ static int btf_ext_setup_line_info(struct btf_ext *btf_ext) return btf_ext_setup_info(btf_ext, ¶m); } -static int btf_ext_setup_field_reloc(struct btf_ext *btf_ext) +static int btf_ext_setup_core_relos(struct btf_ext *btf_ext) { struct btf_ext_sec_setup_param param = { - .off = btf_ext->hdr->field_reloc_off, - .len = btf_ext->hdr->field_reloc_len, - .min_rec_size = sizeof(struct bpf_field_reloc), - .ext_info = &btf_ext->field_reloc_info, - .desc = "field_reloc", + .off = btf_ext->hdr->core_relo_off, + .len = btf_ext->hdr->core_relo_len, + .min_rec_size = sizeof(struct bpf_core_relo), + .ext_info = &btf_ext->core_relo_info, + .desc = "core_relo", }; return btf_ext_setup_info(btf_ext, ¶m); @@ -985,7 +2779,10 @@ static int btf_ext_parse_hdr(__u8 *data, __u32 data_size) return -EINVAL; } - if (hdr->magic != BTF_MAGIC) { + if (hdr->magic == bswap_16(BTF_MAGIC)) { + pr_warn("BTF.ext in non-native endianness is not supported\n"); + return -ENOTSUP; + } else if (hdr->magic != BTF_MAGIC) { pr_debug("Invalid BTF.ext magic:%x\n", hdr->magic); return -EINVAL; } @@ -1010,24 +2807,23 @@ static int btf_ext_parse_hdr(__u8 *data, __u32 data_size) void btf_ext__free(struct btf_ext *btf_ext) { - if (!btf_ext) + if (IS_ERR_OR_NULL(btf_ext)) return; + free(btf_ext->func_info.sec_idxs); + free(btf_ext->line_info.sec_idxs); + free(btf_ext->core_relo_info.sec_idxs); free(btf_ext->data); free(btf_ext); } -struct btf_ext *btf_ext__new(__u8 *data, __u32 size) +struct btf_ext *btf_ext__new(const __u8 *data, __u32 size) { struct btf_ext *btf_ext; int err; - err = btf_ext_parse_hdr(data, size); - if (err) - return ERR_PTR(err); - btf_ext = calloc(1, sizeof(struct btf_ext)); if (!btf_ext) - return ERR_PTR(-ENOMEM); + return libbpf_err_ptr(-ENOMEM); btf_ext->data_size = size; btf_ext->data = malloc(size); @@ -1037,9 +2833,15 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size) } memcpy(btf_ext->data, data, size); - if (btf_ext->hdr->hdr_len < - offsetofend(struct btf_ext_header, line_info_len)) + err = btf_ext_parse_hdr(btf_ext->data, size); + if (err) + goto done; + + if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, line_info_len)) { + err = -EINVAL; goto done; + } + err = btf_ext_setup_func_info(btf_ext); if (err) goto done; @@ -1048,17 +2850,17 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size) if (err) goto done; - if (btf_ext->hdr->hdr_len < - offsetofend(struct btf_ext_header, field_reloc_len)) - goto done; - err = btf_ext_setup_field_reloc(btf_ext); + if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) + goto done; /* skip core relos parsing */ + + err = btf_ext_setup_core_relos(btf_ext); if (err) goto done; done: if (err) { btf_ext__free(btf_ext); - return ERR_PTR(err); + return libbpf_err_ptr(err); } return btf_ext; @@ -1070,87 +2872,11 @@ const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size) return btf_ext->data; } -static int btf_ext_reloc_info(const struct btf *btf, - const struct btf_ext_info *ext_info, - const char *sec_name, __u32 insns_cnt, - void **info, __u32 *cnt) -{ - __u32 sec_hdrlen = sizeof(struct btf_ext_info_sec); - __u32 i, record_size, existing_len, records_len; - struct btf_ext_info_sec *sinfo; - const char *info_sec_name; - __u64 remain_len; - void *data; - - record_size = ext_info->rec_size; - sinfo = ext_info->info; - remain_len = ext_info->len; - while (remain_len > 0) { - records_len = sinfo->num_info * record_size; - info_sec_name = btf__name_by_offset(btf, sinfo->sec_name_off); - if (strcmp(info_sec_name, sec_name)) { - remain_len -= sec_hdrlen + records_len; - sinfo = (void *)sinfo + sec_hdrlen + records_len; - continue; - } - - existing_len = (*cnt) * record_size; - data = realloc(*info, existing_len + records_len); - if (!data) - return -ENOMEM; - - memcpy(data + existing_len, sinfo->data, records_len); - /* adjust insn_off only, the rest data will be passed - * to the kernel. - */ - for (i = 0; i < sinfo->num_info; i++) { - __u32 *insn_off; - - insn_off = data + existing_len + (i * record_size); - *insn_off = *insn_off / sizeof(struct bpf_insn) + - insns_cnt; - } - *info = data; - *cnt += sinfo->num_info; - return 0; - } - - return -ENOENT; -} - -int btf_ext__reloc_func_info(const struct btf *btf, - const struct btf_ext *btf_ext, - const char *sec_name, __u32 insns_cnt, - void **func_info, __u32 *cnt) -{ - return btf_ext_reloc_info(btf, &btf_ext->func_info, sec_name, - insns_cnt, func_info, cnt); -} - -int btf_ext__reloc_line_info(const struct btf *btf, - const struct btf_ext *btf_ext, - const char *sec_name, __u32 insns_cnt, - void **line_info, __u32 *cnt) -{ - return btf_ext_reloc_info(btf, &btf_ext->line_info, sec_name, - insns_cnt, line_info, cnt); -} - -__u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext) -{ - return btf_ext->func_info.rec_size; -} - -__u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext) -{ - return btf_ext->line_info.rec_size; -} - struct btf_dedup; -static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, - const struct btf_dedup_opts *opts); +static struct btf_dedup *btf_dedup_new(struct btf *btf, const struct btf_dedup_opts *opts); static void btf_dedup_free(struct btf_dedup *d); +static int btf_dedup_prep(struct btf_dedup *d); static int btf_dedup_strings(struct btf_dedup *d); static int btf_dedup_prim_types(struct btf_dedup *d); static int btf_dedup_struct_types(struct btf_dedup *d); @@ -1295,17 +3021,30 @@ static int btf_dedup_remap_types(struct btf_dedup *d); * deduplicating structs/unions is described in greater details in comments for * `btf_dedup_is_equiv` function. */ -int btf__dedup(struct btf *btf, struct btf_ext *btf_ext, - const struct btf_dedup_opts *opts) +int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts) { - struct btf_dedup *d = btf_dedup_new(btf, btf_ext, opts); + struct btf_dedup *d; int err; + if (!OPTS_VALID(opts, btf_dedup_opts)) + return libbpf_err(-EINVAL); + + d = btf_dedup_new(btf, opts); if (IS_ERR(d)) { pr_debug("btf_dedup_new failed: %ld", PTR_ERR(d)); - return -EINVAL; + return libbpf_err(-EINVAL); } + if (btf_ensure_modifiable(btf)) { + err = -ENOMEM; + goto done; + } + + err = btf_dedup_prep(d); + if (err) { + pr_debug("btf_dedup_prep failed:%d\n", err); + goto done; + } err = btf_dedup_strings(d); if (err < 0) { pr_debug("btf_dedup_strings failed:%d\n", err); @@ -1339,7 +3078,7 @@ int btf__dedup(struct btf *btf, struct btf_ext *btf_ext, done: btf_dedup_free(d); - return err; + return libbpf_err(err); } #define BTF_UNPROCESSED_ID ((__u32)-1) @@ -1368,21 +3107,17 @@ struct btf_dedup { __u32 *hypot_list; size_t hypot_cnt; size_t hypot_cap; + /* Whether hypothetical mapping, if successful, would need to adjust + * already canonicalized types (due to a new forward declaration to + * concrete type resolution). In such case, during split BTF dedup + * candidate type would still be considered as different, because base + * BTF is considered to be immutable. + */ + bool hypot_adjust_canon; /* Various option modifying behavior of algorithm */ struct btf_dedup_opts opts; -}; - -struct btf_str_ptr { - const char *str; - __u32 new_off; - bool used; -}; - -struct btf_str_ptrs { - struct btf_str_ptr *ptrs; - const char *data; - __u32 cnt; - __u32 cap; + /* temporary strings deduplication state */ + struct strset *strs_set; }; static long hash_combine(long h, long value) @@ -1406,7 +3141,7 @@ static int btf_dedup_hypot_map_add(struct btf_dedup *d, __u32 *new_list; d->hypot_cap += max((size_t)16, d->hypot_cap / 2); - new_list = realloc(d->hypot_list, sizeof(__u32) * d->hypot_cap); + new_list = libbpf_reallocarray(d->hypot_list, d->hypot_cap, sizeof(__u32)); if (!new_list) return -ENOMEM; d->hypot_list = new_list; @@ -1423,6 +3158,7 @@ static void btf_dedup_clear_hypot_map(struct btf_dedup *d) for (i = 0; i < d->hypot_cnt; i++) d->hypot_map[d->hypot_list[i]] = BTF_UNPROCESSED_ID; d->hypot_cnt = 0; + d->hypot_adjust_canon = false; } static void btf_dedup_free(struct btf_dedup *d) @@ -1457,23 +3193,20 @@ static bool btf_dedup_equal_fn(const void *k1, const void *k2, void *ctx) return k1 == k2; } -static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, - const struct btf_dedup_opts *opts) +static struct btf_dedup *btf_dedup_new(struct btf *btf, const struct btf_dedup_opts *opts) { struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup)); hashmap_hash_fn hash_fn = btf_dedup_identity_hash_fn; - int i, err = 0; + int i, err = 0, type_cnt; if (!d) return ERR_PTR(-ENOMEM); - d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds; - /* dedup_table_size is now used only to force collisions in tests */ - if (opts && opts->dedup_table_size == 1) + if (OPTS_GET(opts, force_collisions, false)) hash_fn = btf_dedup_collision_hash_fn; d->btf = btf; - d->btf_ext = btf_ext; + d->btf_ext = OPTS_GET(opts, btf_ext, NULL); d->dedup_table = hashmap__new(hash_fn, btf_dedup_equal_fn, NULL); if (IS_ERR(d->dedup_table)) { @@ -1482,15 +3215,16 @@ static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, goto done; } - d->map = malloc(sizeof(__u32) * (1 + btf->nr_types)); + type_cnt = btf__type_cnt(btf); + d->map = malloc(sizeof(__u32) * type_cnt); if (!d->map) { err = -ENOMEM; goto done; } /* special BTF "void" type is made canonical immediately */ d->map[0] = 0; - for (i = 1; i <= btf->nr_types; i++) { - struct btf_type *t = d->btf->types[i]; + for (i = 1; i < type_cnt; i++) { + struct btf_type *t = btf_type_by_id(d->btf, i); /* VAR and DATASEC are never deduped and are self-canonical */ if (btf_is_var(t) || btf_is_datasec(t)) @@ -1499,12 +3233,12 @@ static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, d->map[i] = BTF_UNPROCESSED_ID; } - d->hypot_map = malloc(sizeof(__u32) * (1 + btf->nr_types)); + d->hypot_map = malloc(sizeof(__u32) * type_cnt); if (!d->hypot_map) { err = -ENOMEM; goto done; } - for (i = 0; i <= btf->nr_types; i++) + for (i = 0; i < type_cnt; i++) d->hypot_map[i] = BTF_UNPROCESSED_ID; done: @@ -1516,157 +3250,59 @@ done: return d; } -typedef int (*str_off_fn_t)(__u32 *str_off_ptr, void *ctx); - /* * Iterate over all possible places in .BTF and .BTF.ext that can reference * string and pass pointer to it to a provided callback `fn`. */ -static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx) +static int btf_for_each_str_off(struct btf_dedup *d, str_off_visit_fn fn, void *ctx) { - void *line_data_cur, *line_data_end; - int i, j, r, rec_size; - struct btf_type *t; + int i, r; + + for (i = 0; i < d->btf->nr_types; i++) { + struct btf_type *t = btf_type_by_id(d->btf, d->btf->start_id + i); - for (i = 1; i <= d->btf->nr_types; i++) { - t = d->btf->types[i]; - r = fn(&t->name_off, ctx); + r = btf_type_visit_str_offs(t, fn, ctx); if (r) return r; - - switch (btf_kind(t)) { - case BTF_KIND_STRUCT: - case BTF_KIND_UNION: { - struct btf_member *m = btf_members(t); - __u16 vlen = btf_vlen(t); - - for (j = 0; j < vlen; j++) { - r = fn(&m->name_off, ctx); - if (r) - return r; - m++; - } - break; - } - case BTF_KIND_ENUM: { - struct btf_enum *m = btf_enum(t); - __u16 vlen = btf_vlen(t); - - for (j = 0; j < vlen; j++) { - r = fn(&m->name_off, ctx); - if (r) - return r; - m++; - } - break; - } - case BTF_KIND_FUNC_PROTO: { - struct btf_param *m = btf_params(t); - __u16 vlen = btf_vlen(t); - - for (j = 0; j < vlen; j++) { - r = fn(&m->name_off, ctx); - if (r) - return r; - m++; - } - break; - } - default: - break; - } } if (!d->btf_ext) return 0; - line_data_cur = d->btf_ext->line_info.info; - line_data_end = d->btf_ext->line_info.info + d->btf_ext->line_info.len; - rec_size = d->btf_ext->line_info.rec_size; - - while (line_data_cur < line_data_end) { - struct btf_ext_info_sec *sec = line_data_cur; - struct bpf_line_info_min *line_info; - __u32 num_info = sec->num_info; - - r = fn(&sec->sec_name_off, ctx); - if (r) - return r; - - line_data_cur += sizeof(struct btf_ext_info_sec); - for (i = 0; i < num_info; i++) { - line_info = line_data_cur; - r = fn(&line_info->file_name_off, ctx); - if (r) - return r; - r = fn(&line_info->line_off, ctx); - if (r) - return r; - line_data_cur += rec_size; - } - } + r = btf_ext_visit_str_offs(d->btf_ext, fn, ctx); + if (r) + return r; return 0; } -static int str_sort_by_content(const void *a1, const void *a2) +static int strs_dedup_remap_str_off(__u32 *str_off_ptr, void *ctx) { - const struct btf_str_ptr *p1 = a1; - const struct btf_str_ptr *p2 = a2; + struct btf_dedup *d = ctx; + __u32 str_off = *str_off_ptr; + const char *s; + int off, err; - return strcmp(p1->str, p2->str); -} - -static int str_sort_by_offset(const void *a1, const void *a2) -{ - const struct btf_str_ptr *p1 = a1; - const struct btf_str_ptr *p2 = a2; - - if (p1->str != p2->str) - return p1->str < p2->str ? -1 : 1; - return 0; -} - -static int btf_dedup_str_ptr_cmp(const void *str_ptr, const void *pelem) -{ - const struct btf_str_ptr *p = pelem; - - if (str_ptr != p->str) - return (const char *)str_ptr < p->str ? -1 : 1; - return 0; -} - -static int btf_str_mark_as_used(__u32 *str_off_ptr, void *ctx) -{ - struct btf_str_ptrs *strs; - struct btf_str_ptr *s; - - if (*str_off_ptr == 0) + /* don't touch empty string or string in main BTF */ + if (str_off == 0 || str_off < d->btf->start_str_off) return 0; - strs = ctx; - s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt, - sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp); - if (!s) - return -EINVAL; - s->used = true; - return 0; -} - -static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx) -{ - struct btf_str_ptrs *strs; - struct btf_str_ptr *s; + s = btf__str_by_offset(d->btf, str_off); + if (d->btf->base_btf) { + err = btf__find_str(d->btf->base_btf, s); + if (err >= 0) { + *str_off_ptr = err; + return 0; + } + if (err != -ENOENT) + return err; + } - if (*str_off_ptr == 0) - return 0; + off = strset__add_str(d->strs_set, s); + if (off < 0) + return off; - strs = ctx; - s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt, - sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp); - if (!s) - return -EINVAL; - *str_off_ptr = s->new_off; + *str_off_ptr = d->btf->start_str_off + off; return 0; } @@ -1683,116 +3319,43 @@ static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx) */ static int btf_dedup_strings(struct btf_dedup *d) { - const struct btf_header *hdr = d->btf->hdr; - char *start = (char *)d->btf->nohdr_data + hdr->str_off; - char *end = start + d->btf->hdr->str_len; - char *p = start, *tmp_strs = NULL; - struct btf_str_ptrs strs = { - .cnt = 0, - .cap = 0, - .ptrs = NULL, - .data = start, - }; - int i, j, err = 0, grp_idx; - bool grp_used; - - /* build index of all strings */ - while (p < end) { - if (strs.cnt + 1 > strs.cap) { - struct btf_str_ptr *new_ptrs; - - strs.cap += max(strs.cnt / 2, 16U); - new_ptrs = realloc(strs.ptrs, - sizeof(strs.ptrs[0]) * strs.cap); - if (!new_ptrs) { - err = -ENOMEM; - goto done; - } - strs.ptrs = new_ptrs; - } - - strs.ptrs[strs.cnt].str = p; - strs.ptrs[strs.cnt].used = false; + int err; - p += strlen(p) + 1; - strs.cnt++; - } + if (d->btf->strs_deduped) + return 0; - /* temporary storage for deduplicated strings */ - tmp_strs = malloc(d->btf->hdr->str_len); - if (!tmp_strs) { - err = -ENOMEM; - goto done; + d->strs_set = strset__new(BTF_MAX_STR_OFFSET, NULL, 0); + if (IS_ERR(d->strs_set)) { + err = PTR_ERR(d->strs_set); + goto err_out; } - /* mark all used strings */ - strs.ptrs[0].used = true; - err = btf_for_each_str_off(d, btf_str_mark_as_used, &strs); - if (err) - goto done; - - /* sort strings by context, so that we can identify duplicates */ - qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_content); - - /* - * iterate groups of equal strings and if any instance in a group was - * referenced, emit single instance and remember new offset - */ - p = tmp_strs; - grp_idx = 0; - grp_used = strs.ptrs[0].used; - /* iterate past end to avoid code duplication after loop */ - for (i = 1; i <= strs.cnt; i++) { - /* - * when i == strs.cnt, we want to skip string comparison and go - * straight to handling last group of strings (otherwise we'd - * need to handle last group after the loop w/ duplicated code) - */ - if (i < strs.cnt && - !strcmp(strs.ptrs[i].str, strs.ptrs[grp_idx].str)) { - grp_used = grp_used || strs.ptrs[i].used; - continue; - } - - /* - * this check would have been required after the loop to handle - * last group of strings, but due to <= condition in a loop - * we avoid that duplication + if (!d->btf->base_btf) { + /* insert empty string; we won't be looking it up during strings + * dedup, but it's good to have it for generic BTF string lookups */ - if (grp_used) { - int new_off = p - tmp_strs; - __u32 len = strlen(strs.ptrs[grp_idx].str); - - memmove(p, strs.ptrs[grp_idx].str, len + 1); - for (j = grp_idx; j < i; j++) - strs.ptrs[j].new_off = new_off; - p += len + 1; - } - - if (i < strs.cnt) { - grp_idx = i; - grp_used = strs.ptrs[i].used; - } + err = strset__add_str(d->strs_set, ""); + if (err < 0) + goto err_out; } - /* replace original strings with deduped ones */ - d->btf->hdr->str_len = p - tmp_strs; - memmove(start, tmp_strs, d->btf->hdr->str_len); - end = start + d->btf->hdr->str_len; - - /* restore original order for further binary search lookups */ - qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_offset); - /* remap string offsets */ - err = btf_for_each_str_off(d, btf_str_remap_offset, &strs); + err = btf_for_each_str_off(d, strs_dedup_remap_str_off, d); if (err) - goto done; + goto err_out; + + /* replace BTF string data and hash with deduped ones */ + strset__free(d->btf->strs_set); + d->btf->hdr->str_len = strset__data_size(d->strs_set); + d->btf->strs_set = d->strs_set; + d->strs_set = NULL; + d->btf->strs_deduped = true; + return 0; - d->btf->hdr->str_len = end - start; +err_out: + strset__free(d->strs_set); + d->strs_set = NULL; -done: - free(tmp_strs); - free(strs.ptrs); return err; } @@ -1813,8 +3376,8 @@ static bool btf_equal_common(struct btf_type *t1, struct btf_type *t2) t1->size == t2->size; } -/* Calculate type signature hash of INT. */ -static long btf_hash_int(struct btf_type *t) +/* Calculate type signature hash of INT or TAG. */ +static long btf_hash_int_decl_tag(struct btf_type *t) { __u32 info = *(__u32 *)(t + 1); long h; @@ -1824,8 +3387,8 @@ static long btf_hash_int(struct btf_type *t) return h; } -/* Check structural equality of two INTs. */ -static bool btf_equal_int(struct btf_type *t1, struct btf_type *t2) +/* Check structural equality of two INTs or TAGs. */ +static bool btf_equal_int_tag(struct btf_type *t1, struct btf_type *t2) { __u32 info1, info2; @@ -1836,7 +3399,7 @@ static bool btf_equal_int(struct btf_type *t1, struct btf_type *t2) return info1 == info2; } -/* Calculate type signature hash of ENUM. */ +/* Calculate type signature hash of ENUM/ENUM64. */ static long btf_hash_enum(struct btf_type *t) { long h; @@ -1870,9 +3433,31 @@ static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2) return true; } +static bool btf_equal_enum64(struct btf_type *t1, struct btf_type *t2) +{ + const struct btf_enum64 *m1, *m2; + __u16 vlen; + int i; + + if (!btf_equal_common(t1, t2)) + return false; + + vlen = btf_vlen(t1); + m1 = btf_enum64(t1); + m2 = btf_enum64(t2); + for (i = 0; i < vlen; i++) { + if (m1->name_off != m2->name_off || m1->val_lo32 != m2->val_lo32 || + m1->val_hi32 != m2->val_hi32) + return false; + m1++; + m2++; + } + return true; +} + static inline bool btf_is_enum_fwd(struct btf_type *t) { - return btf_is_enum(t) && btf_vlen(t) == 0; + return btf_is_any_enum(t) && btf_vlen(t) == 0; } static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2) @@ -1885,6 +3470,17 @@ static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2) t1->size == t2->size; } +static bool btf_compat_enum64(struct btf_type *t1, struct btf_type *t2) +{ + if (!btf_is_enum_fwd(t1) && !btf_is_enum_fwd(t2)) + return btf_equal_enum64(t1, t2); + + /* ignore vlen when comparing */ + return t1->name_off == t2->name_off && + (t1->info & ~0xffff) == (t2->info & ~0xffff) && + t1->size == t2->size; +} + /* * Calculate type signature hash of STRUCT/UNION, ignoring referenced type IDs, * as referenced type IDs equivalence is established separately during type @@ -1907,8 +3503,8 @@ static long btf_hash_struct(struct btf_type *t) } /* - * Check structural compatibility of two FUNC_PROTOs, ignoring referenced type - * IDs. This check is performed during type graph equivalence check and + * Check structural compatibility of two STRUCTs/UNIONs, ignoring referenced + * type IDs. This check is performed during type graph equivalence check and * referenced types equivalence is checked separately. */ static bool btf_shallow_equal_struct(struct btf_type *t1, struct btf_type *t2) @@ -2057,6 +3653,70 @@ static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2) return true; } +/* Prepare split BTF for deduplication by calculating hashes of base BTF's + * types and initializing the rest of the state (canonical type mapping) for + * the fixed base BTF part. + */ +static int btf_dedup_prep(struct btf_dedup *d) +{ + struct btf_type *t; + int type_id; + long h; + + if (!d->btf->base_btf) + return 0; + + for (type_id = 1; type_id < d->btf->start_id; type_id++) { + t = btf_type_by_id(d->btf, type_id); + + /* all base BTF types are self-canonical by definition */ + d->map[type_id] = type_id; + + switch (btf_kind(t)) { + case BTF_KIND_VAR: + case BTF_KIND_DATASEC: + /* VAR and DATASEC are never hash/deduplicated */ + continue; + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_FWD: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + case BTF_KIND_FLOAT: + case BTF_KIND_TYPE_TAG: + h = btf_hash_common(t); + break; + case BTF_KIND_INT: + case BTF_KIND_DECL_TAG: + h = btf_hash_int_decl_tag(t); + break; + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + h = btf_hash_enum(t); + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + h = btf_hash_struct(t); + break; + case BTF_KIND_ARRAY: + h = btf_hash_array(t); + break; + case BTF_KIND_FUNC_PROTO: + h = btf_hash_fnproto(t); + break; + default: + pr_debug("unknown kind %d for type [%d]\n", btf_kind(t), type_id); + return -EINVAL; + } + if (btf_dedup_table_add(d, h, type_id)) + return -ENOMEM; + } + + return 0; +} + /* * Deduplicate primitive types, that can't reference other types, by calculating * their type signature hash and comparing them with any possible canonical @@ -2065,7 +3725,7 @@ static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2) */ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) { - struct btf_type *t = d->btf->types[type_id]; + struct btf_type *t = btf_type_by_id(d->btf, type_id); struct hashmap_entry *hash_entry; struct btf_type *cand; /* if we don't find equivalent type, then we are canonical */ @@ -2086,14 +3746,16 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) case BTF_KIND_FUNC_PROTO: case BTF_KIND_VAR: case BTF_KIND_DATASEC: + case BTF_KIND_DECL_TAG: + case BTF_KIND_TYPE_TAG: return 0; case BTF_KIND_INT: - h = btf_hash_int(t); + h = btf_hash_int_decl_tag(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; - if (btf_equal_int(t, cand)) { + cand = btf_type_by_id(d->btf, cand_id); + if (btf_equal_int_tag(t, cand)) { new_id = cand_id; break; } @@ -2104,13 +3766,11 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) h = btf_hash_enum(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; + cand = btf_type_by_id(d->btf, cand_id); if (btf_equal_enum(t, cand)) { new_id = cand_id; break; } - if (d->opts.dont_resolve_fwds) - continue; if (btf_compat_enum(t, cand)) { if (btf_is_enum_fwd(t)) { /* resolve fwd to full enum */ @@ -2123,11 +3783,33 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) } break; + case BTF_KIND_ENUM64: + h = btf_hash_enum(t); + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = btf_type_by_id(d->btf, cand_id); + if (btf_equal_enum64(t, cand)) { + new_id = cand_id; + break; + } + if (btf_compat_enum64(t, cand)) { + if (btf_is_enum_fwd(t)) { + /* resolve fwd to full enum */ + new_id = cand_id; + break; + } + /* resolve canonical enum fwd to full enum */ + d->map[cand_id] = type_id; + } + } + break; + case BTF_KIND_FWD: + case BTF_KIND_FLOAT: h = btf_hash_common(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; + cand = btf_type_by_id(d->btf, cand_id); if (btf_equal_common(t, cand)) { new_id = cand_id; break; @@ -2150,8 +3832,8 @@ static int btf_dedup_prim_types(struct btf_dedup *d) { int i, err; - for (i = 1; i <= d->btf->nr_types; i++) { - err = btf_dedup_prim_type(d, i); + for (i = 0; i < d->btf->nr_types; i++) { + err = btf_dedup_prim_type(d, d->btf->start_id + i); if (err) return err; } @@ -2186,13 +3868,13 @@ static uint32_t resolve_fwd_id(struct btf_dedup *d, uint32_t type_id) { __u32 orig_type_id = type_id; - if (!btf_is_fwd(d->btf->types[type_id])) + if (!btf_is_fwd(btf__type_by_id(d->btf, type_id))) return type_id; while (is_type_mapped(d, type_id) && d->map[type_id] != type_id) type_id = d->map[type_id]; - if (!btf_is_fwd(d->btf->types[type_id])) + if (!btf_is_fwd(btf__type_by_id(d->btf, type_id))) return type_id; return orig_type_id; @@ -2204,6 +3886,44 @@ static inline __u16 btf_fwd_kind(struct btf_type *t) return btf_kflag(t) ? BTF_KIND_UNION : BTF_KIND_STRUCT; } +/* Check if given two types are identical ARRAY definitions */ +static int btf_dedup_identical_arrays(struct btf_dedup *d, __u32 id1, __u32 id2) +{ + struct btf_type *t1, *t2; + + t1 = btf_type_by_id(d->btf, id1); + t2 = btf_type_by_id(d->btf, id2); + if (!btf_is_array(t1) || !btf_is_array(t2)) + return 0; + + return btf_equal_array(t1, t2); +} + +/* Check if given two types are identical STRUCT/UNION definitions */ +static bool btf_dedup_identical_structs(struct btf_dedup *d, __u32 id1, __u32 id2) +{ + const struct btf_member *m1, *m2; + struct btf_type *t1, *t2; + int n, i; + + t1 = btf_type_by_id(d->btf, id1); + t2 = btf_type_by_id(d->btf, id2); + + if (!btf_is_composite(t1) || btf_kind(t1) != btf_kind(t2)) + return false; + + if (!btf_shallow_equal_struct(t1, t2)) + return false; + + m1 = btf_members(t1); + m2 = btf_members(t2); + for (i = 0, n = btf_vlen(t1); i < n; i++, m1++, m2++) { + if (m1->type != m2->type) + return false; + } + return true; +} + /* * Check equivalence of BTF type graph formed by candidate struct/union (we'll * call it "candidate graph" in this description for brevity) to a type graph @@ -2314,14 +4034,36 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, canon_id = resolve_fwd_id(d, canon_id); hypot_type_id = d->hypot_map[canon_id]; - if (hypot_type_id <= BTF_MAX_NR_TYPES) - return hypot_type_id == cand_id; + if (hypot_type_id <= BTF_MAX_NR_TYPES) { + if (hypot_type_id == cand_id) + return 1; + /* In some cases compiler will generate different DWARF types + * for *identical* array type definitions and use them for + * different fields within the *same* struct. This breaks type + * equivalence check, which makes an assumption that candidate + * types sub-graph has a consistent and deduped-by-compiler + * types within a single CU. So work around that by explicitly + * allowing identical array types here. + */ + if (btf_dedup_identical_arrays(d, hypot_type_id, cand_id)) + return 1; + /* It turns out that similar situation can happen with + * struct/union sometimes, sigh... Handle the case where + * structs/unions are exactly the same, down to the referenced + * type IDs. Anything more complicated (e.g., if referenced + * types are different, but equivalent) is *way more* + * complicated and requires a many-to-many equivalence mapping. + */ + if (btf_dedup_identical_structs(d, hypot_type_id, cand_id)) + return 1; + return 0; + } if (btf_dedup_hypot_map_add(d, canon_id, cand_id)) return -ENOMEM; - cand_type = d->btf->types[cand_id]; - canon_type = d->btf->types[canon_id]; + cand_type = btf_type_by_id(d->btf, cand_id); + canon_type = btf_type_by_id(d->btf, canon_id); cand_kind = btf_kind(cand_type); canon_kind = btf_kind(canon_type); @@ -2329,8 +4071,7 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, return 0; /* FWD <--> STRUCT/UNION equivalence check, if enabled */ - if (!d->opts.dont_resolve_fwds - && (cand_kind == BTF_KIND_FWD || canon_kind == BTF_KIND_FWD) + if ((cand_kind == BTF_KIND_FWD || canon_kind == BTF_KIND_FWD) && cand_kind != canon_kind) { __u16 real_kind; __u16 fwd_kind; @@ -2341,6 +4082,9 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, } else { real_kind = cand_kind; fwd_kind = btf_fwd_kind(canon_type); + /* we'd need to resolve base FWD to STRUCT/UNION */ + if (fwd_kind == real_kind && canon_id < d->btf->start_id) + d->hypot_adjust_canon = true; } return fwd_kind == real_kind; } @@ -2350,15 +4094,16 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, switch (cand_kind) { case BTF_KIND_INT: - return btf_equal_int(cand_type, canon_type); + return btf_equal_int_tag(cand_type, canon_type); case BTF_KIND_ENUM: - if (d->opts.dont_resolve_fwds) - return btf_equal_enum(cand_type, canon_type); - else - return btf_compat_enum(cand_type, canon_type); + return btf_compat_enum(cand_type, canon_type); + + case BTF_KIND_ENUM64: + return btf_compat_enum64(cand_type, canon_type); case BTF_KIND_FWD: + case BTF_KIND_FLOAT: return btf_equal_common(cand_type, canon_type); case BTF_KIND_CONST: @@ -2367,6 +4112,7 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, case BTF_KIND_PTR: case BTF_KIND_TYPEDEF: case BTF_KIND_FUNC: + case BTF_KIND_TYPE_TAG: if (cand_type->info != canon_type->info) return 0; return btf_dedup_is_equiv(d, cand_type->type, canon_type->type); @@ -2378,8 +4124,7 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, return 0; cand_arr = btf_array(cand_type); canon_arr = btf_array(canon_type); - eq = btf_dedup_is_equiv(d, - cand_arr->index_type, canon_arr->index_type); + eq = btf_dedup_is_equiv(d, cand_arr->index_type, canon_arr->index_type); if (eq <= 0) return eq; return btf_dedup_is_equiv(d, cand_arr->type, canon_arr->type); @@ -2462,18 +4207,18 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, */ static void btf_dedup_merge_hypot_map(struct btf_dedup *d) { - __u32 cand_type_id, targ_type_id; + __u32 canon_type_id, targ_type_id; __u16 t_kind, c_kind; __u32 t_id, c_id; int i; for (i = 0; i < d->hypot_cnt; i++) { - cand_type_id = d->hypot_list[i]; - targ_type_id = d->hypot_map[cand_type_id]; + canon_type_id = d->hypot_list[i]; + targ_type_id = d->hypot_map[canon_type_id]; t_id = resolve_type_id(d, targ_type_id); - c_id = resolve_type_id(d, cand_type_id); - t_kind = btf_kind(d->btf->types[t_id]); - c_kind = btf_kind(d->btf->types[c_id]); + c_id = resolve_type_id(d, canon_type_id); + t_kind = btf_kind(btf__type_by_id(d->btf, t_id)); + c_kind = btf_kind(btf__type_by_id(d->btf, c_id)); /* * Resolve FWD into STRUCT/UNION. * It's ok to resolve FWD into STRUCT/UNION that's not yet @@ -2486,9 +4231,26 @@ static void btf_dedup_merge_hypot_map(struct btf_dedup *d) * stability is not a requirement for STRUCT/UNION equivalence * checks, though. */ + + /* if it's the split BTF case, we still need to point base FWD + * to STRUCT/UNION in a split BTF, because FWDs from split BTF + * will be resolved against base FWD. If we don't point base + * canonical FWD to the resolved STRUCT/UNION, then all the + * FWDs in split BTF won't be correctly resolved to a proper + * STRUCT/UNION. + */ if (t_kind != BTF_KIND_FWD && c_kind == BTF_KIND_FWD) d->map[c_id] = t_id; - else if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD) + + /* if graph equivalence determined that we'd need to adjust + * base canonical types, then we need to only point base FWDs + * to STRUCTs/UNIONs and do no more modifications. For all + * other purposes the type graphs were not equivalent. + */ + if (d->hypot_adjust_canon) + continue; + + if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD) d->map[t_id] = c_id; if ((t_kind == BTF_KIND_STRUCT || t_kind == BTF_KIND_UNION) && @@ -2541,7 +4303,7 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) if (d->map[type_id] <= BTF_MAX_NR_TYPES) return 0; - t = d->btf->types[type_id]; + t = btf_type_by_id(d->btf, type_id); kind = btf_kind(t); if (kind != BTF_KIND_STRUCT && kind != BTF_KIND_UNION) @@ -2562,7 +4324,7 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) * creating a loop (FWD -> STRUCT and STRUCT -> FWD), because * FWD and compatible STRUCT/UNION are considered equivalent. */ - cand_type = d->btf->types[cand_id]; + cand_type = btf_type_by_id(d->btf, cand_id); if (!btf_shallow_equal_struct(t, cand_type)) continue; @@ -2572,8 +4334,10 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) return eq; if (!eq) continue; - new_id = cand_id; btf_dedup_merge_hypot_map(d); + if (d->hypot_adjust_canon) /* not really equivalent */ + continue; + new_id = cand_id; break; } @@ -2588,8 +4352,8 @@ static int btf_dedup_struct_types(struct btf_dedup *d) { int i, err; - for (i = 1; i <= d->btf->nr_types; i++) { - err = btf_dedup_struct_type(d, i); + for (i = 0; i < d->btf->nr_types; i++) { + err = btf_dedup_struct_type(d, d->btf->start_id + i); if (err) return err; } @@ -2634,7 +4398,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) if (d->map[type_id] <= BTF_MAX_NR_TYPES) return resolve_type_id(d, type_id); - t = d->btf->types[type_id]; + t = btf_type_by_id(d->btf, type_id); d->map[type_id] = BTF_IN_PROGRESS_ID; switch (btf_kind(t)) { @@ -2644,6 +4408,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) case BTF_KIND_PTR: case BTF_KIND_TYPEDEF: case BTF_KIND_FUNC: + case BTF_KIND_TYPE_TAG: ref_type_id = btf_dedup_ref_type(d, t->type); if (ref_type_id < 0) return ref_type_id; @@ -2652,7 +4417,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) h = btf_hash_common(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; + cand = btf_type_by_id(d->btf, cand_id); if (btf_equal_common(t, cand)) { new_id = cand_id; break; @@ -2660,6 +4425,23 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) } break; + case BTF_KIND_DECL_TAG: + ref_type_id = btf_dedup_ref_type(d, t->type); + if (ref_type_id < 0) + return ref_type_id; + t->type = ref_type_id; + + h = btf_hash_int_decl_tag(t); + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = btf_type_by_id(d->btf, cand_id); + if (btf_equal_int_tag(t, cand)) { + new_id = cand_id; + break; + } + } + break; + case BTF_KIND_ARRAY: { struct btf_array *info = btf_array(t); @@ -2676,7 +4458,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) h = btf_hash_array(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; + cand = btf_type_by_id(d->btf, cand_id); if (btf_equal_array(t, cand)) { new_id = cand_id; break; @@ -2708,7 +4490,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) h = btf_hash_fnproto(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; + cand = btf_type_by_id(d->btf, cand_id); if (btf_equal_fnproto(t, cand)) { new_id = cand_id; break; @@ -2732,8 +4514,8 @@ static int btf_dedup_ref_types(struct btf_dedup *d) { int i, err; - for (i = 1; i <= d->btf->nr_types; i++) { - err = btf_dedup_ref_type(d, i); + for (i = 0; i < d->btf->nr_types; i++) { + err = btf_dedup_ref_type(d, d->btf->start_id + i); if (err < 0) return err; } @@ -2756,51 +4538,49 @@ static int btf_dedup_ref_types(struct btf_dedup *d) */ static int btf_dedup_compact_types(struct btf_dedup *d) { - struct btf_type **new_types; - __u32 next_type_id = 1; - char *types_start, *p; - int i, len; + __u32 *new_offs; + __u32 next_type_id = d->btf->start_id; + const struct btf_type *t; + void *p; + int i, id, len; /* we are going to reuse hypot_map to store compaction remapping */ d->hypot_map[0] = 0; - for (i = 1; i <= d->btf->nr_types; i++) - d->hypot_map[i] = BTF_UNPROCESSED_ID; + /* base BTF types are not renumbered */ + for (id = 1; id < d->btf->start_id; id++) + d->hypot_map[id] = id; + for (i = 0, id = d->btf->start_id; i < d->btf->nr_types; i++, id++) + d->hypot_map[id] = BTF_UNPROCESSED_ID; - types_start = d->btf->nohdr_data + d->btf->hdr->type_off; - p = types_start; + p = d->btf->types_data; - for (i = 1; i <= d->btf->nr_types; i++) { - if (d->map[i] != i) + for (i = 0, id = d->btf->start_id; i < d->btf->nr_types; i++, id++) { + if (d->map[id] != id) continue; - len = btf_type_size(d->btf->types[i]); + t = btf__type_by_id(d->btf, id); + len = btf_type_size(t); if (len < 0) return len; - memmove(p, d->btf->types[i], len); - d->hypot_map[i] = next_type_id; - d->btf->types[next_type_id] = (struct btf_type *)p; + memmove(p, t, len); + d->hypot_map[id] = next_type_id; + d->btf->type_offs[next_type_id - d->btf->start_id] = p - d->btf->types_data; p += len; next_type_id++; } /* shrink struct btf's internal types index and update btf_header */ - d->btf->nr_types = next_type_id - 1; - d->btf->types_size = d->btf->nr_types; - d->btf->hdr->type_len = p - types_start; - new_types = realloc(d->btf->types, - (1 + d->btf->nr_types) * sizeof(struct btf_type *)); - if (!new_types) + d->btf->nr_types = next_type_id - d->btf->start_id; + d->btf->type_offs_cap = d->btf->nr_types; + d->btf->hdr->type_len = p - d->btf->types_data; + new_offs = libbpf_reallocarray(d->btf->type_offs, d->btf->type_offs_cap, + sizeof(*new_offs)); + if (d->btf->type_offs_cap && !new_offs) return -ENOMEM; - d->btf->types = new_types; - - /* make sure string section follows type information without gaps */ - d->btf->hdr->str_off = p - (char *)d->btf->nohdr_data; - memmove(p, d->btf->strings, d->btf->hdr->str_len); - d->btf->strings = p; - p += d->btf->hdr->str_len; - - d->btf->data_size = p - (char *)d->btf->data; + d->btf->type_offs = new_offs; + d->btf->hdr->str_off = d->btf->hdr->type_len; + d->btf->raw_size = d->btf->hdr->hdr_len + d->btf->hdr->type_len + d->btf->hdr->str_len; return 0; } @@ -2810,15 +4590,18 @@ static int btf_dedup_compact_types(struct btf_dedup *d) * then mapping it to a deduplicated type ID, stored in btf_dedup->hypot_map, * which is populated during compaction phase. */ -static int btf_dedup_remap_type_id(struct btf_dedup *d, __u32 type_id) +static int btf_dedup_remap_type_id(__u32 *type_id, void *ctx) { + struct btf_dedup *d = ctx; __u32 resolved_type_id, new_type_id; - resolved_type_id = resolve_type_id(d, type_id); + resolved_type_id = resolve_type_id(d, *type_id); new_type_id = d->hypot_map[resolved_type_id]; if (new_type_id > BTF_MAX_NR_TYPES) return -EINVAL; - return new_type_id; + + *type_id = new_type_id; + return 0; } /* @@ -2831,15 +4614,92 @@ static int btf_dedup_remap_type_id(struct btf_dedup *d, __u32 type_id) * referenced from any BTF type (e.g., struct fields, func proto args, etc) to * their final deduped type IDs. */ -static int btf_dedup_remap_type(struct btf_dedup *d, __u32 type_id) +static int btf_dedup_remap_types(struct btf_dedup *d) { - struct btf_type *t = d->btf->types[type_id]; int i, r; + for (i = 0; i < d->btf->nr_types; i++) { + struct btf_type *t = btf_type_by_id(d->btf, d->btf->start_id + i); + + r = btf_type_visit_type_ids(t, btf_dedup_remap_type_id, d); + if (r) + return r; + } + + if (!d->btf_ext) + return 0; + + r = btf_ext_visit_type_ids(d->btf_ext, btf_dedup_remap_type_id, d); + if (r) + return r; + + return 0; +} + +/* + * Probe few well-known locations for vmlinux kernel image and try to load BTF + * data out of it to use for target BTF. + */ +struct btf *btf__load_vmlinux_btf(void) +{ + const char *locations[] = { + /* try canonical vmlinux BTF through sysfs first */ + "/sys/kernel/btf/vmlinux", + /* fall back to trying to find vmlinux on disk otherwise */ + "/boot/vmlinux-%1$s", + "/lib/modules/%1$s/vmlinux-%1$s", + "/lib/modules/%1$s/build/vmlinux", + "/usr/lib/modules/%1$s/kernel/vmlinux", + "/usr/lib/debug/boot/vmlinux-%1$s", + "/usr/lib/debug/boot/vmlinux-%1$s.debug", + "/usr/lib/debug/lib/modules/%1$s/vmlinux", + }; + char path[PATH_MAX + 1]; + struct utsname buf; + struct btf *btf; + int i, err; + + uname(&buf); + + for (i = 0; i < ARRAY_SIZE(locations); i++) { + snprintf(path, PATH_MAX, locations[i], buf.release); + + if (faccessat(AT_FDCWD, path, R_OK, AT_EACCESS)) + continue; + + btf = btf__parse(path, NULL); + err = libbpf_get_error(btf); + pr_debug("loading kernel BTF '%s': %d\n", path, err); + if (err) + continue; + + return btf; + } + + pr_warn("failed to find valid kernel BTF\n"); + return libbpf_err_ptr(-ESRCH); +} + +struct btf *libbpf_find_kernel_btf(void) __attribute__((alias("btf__load_vmlinux_btf"))); + +struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf) +{ + char path[80]; + + snprintf(path, sizeof(path), "/sys/kernel/btf/%s", module_name); + return btf__parse_split(path, vmlinux_btf); +} + +int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx) +{ + int i, n, err; + switch (btf_kind(t)) { case BTF_KIND_INT: + case BTF_KIND_FLOAT: case BTF_KIND_ENUM: - break; + case BTF_KIND_ENUM64: + return 0; case BTF_KIND_FWD: case BTF_KIND_CONST: @@ -2849,175 +4709,193 @@ static int btf_dedup_remap_type(struct btf_dedup *d, __u32 type_id) case BTF_KIND_TYPEDEF: case BTF_KIND_FUNC: case BTF_KIND_VAR: - r = btf_dedup_remap_type_id(d, t->type); - if (r < 0) - return r; - t->type = r; - break; + case BTF_KIND_DECL_TAG: + case BTF_KIND_TYPE_TAG: + return visit(&t->type, ctx); case BTF_KIND_ARRAY: { - struct btf_array *arr_info = btf_array(t); + struct btf_array *a = btf_array(t); - r = btf_dedup_remap_type_id(d, arr_info->type); - if (r < 0) - return r; - arr_info->type = r; - r = btf_dedup_remap_type_id(d, arr_info->index_type); - if (r < 0) - return r; - arr_info->index_type = r; - break; + err = visit(&a->type, ctx); + err = err ?: visit(&a->index_type, ctx); + return err; } case BTF_KIND_STRUCT: case BTF_KIND_UNION: { - struct btf_member *member = btf_members(t); - __u16 vlen = btf_vlen(t); + struct btf_member *m = btf_members(t); - for (i = 0; i < vlen; i++) { - r = btf_dedup_remap_type_id(d, member->type); - if (r < 0) - return r; - member->type = r; - member++; + for (i = 0, n = btf_vlen(t); i < n; i++, m++) { + err = visit(&m->type, ctx); + if (err) + return err; } - break; + return 0; } case BTF_KIND_FUNC_PROTO: { - struct btf_param *param = btf_params(t); - __u16 vlen = btf_vlen(t); + struct btf_param *m = btf_params(t); - r = btf_dedup_remap_type_id(d, t->type); - if (r < 0) - return r; - t->type = r; - - for (i = 0; i < vlen; i++) { - r = btf_dedup_remap_type_id(d, param->type); - if (r < 0) - return r; - param->type = r; - param++; + err = visit(&t->type, ctx); + if (err) + return err; + for (i = 0, n = btf_vlen(t); i < n; i++, m++) { + err = visit(&m->type, ctx); + if (err) + return err; } - break; + return 0; } case BTF_KIND_DATASEC: { - struct btf_var_secinfo *var = btf_var_secinfos(t); - __u16 vlen = btf_vlen(t); + struct btf_var_secinfo *m = btf_var_secinfos(t); - for (i = 0; i < vlen; i++) { - r = btf_dedup_remap_type_id(d, var->type); - if (r < 0) - return r; - var->type = r; - var++; + for (i = 0, n = btf_vlen(t); i < n; i++, m++) { + err = visit(&m->type, ctx); + if (err) + return err; } - break; + return 0; } default: return -EINVAL; } - - return 0; } -static int btf_dedup_remap_types(struct btf_dedup *d) +int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx) { - int i, r; + int i, n, err; - for (i = 1; i <= d->btf->nr_types; i++) { - r = btf_dedup_remap_type(d, i); - if (r < 0) - return r; + err = visit(&t->name_off, ctx); + if (err) + return err; + + switch (btf_kind(t)) { + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + struct btf_member *m = btf_members(t); + + for (i = 0, n = btf_vlen(t); i < n; i++, m++) { + err = visit(&m->name_off, ctx); + if (err) + return err; + } + break; + } + case BTF_KIND_ENUM: { + struct btf_enum *m = btf_enum(t); + + for (i = 0, n = btf_vlen(t); i < n; i++, m++) { + err = visit(&m->name_off, ctx); + if (err) + return err; + } + break; } + case BTF_KIND_ENUM64: { + struct btf_enum64 *m = btf_enum64(t); + + for (i = 0, n = btf_vlen(t); i < n; i++, m++) { + err = visit(&m->name_off, ctx); + if (err) + return err; + } + break; + } + case BTF_KIND_FUNC_PROTO: { + struct btf_param *m = btf_params(t); + + for (i = 0, n = btf_vlen(t); i < n; i++, m++) { + err = visit(&m->name_off, ctx); + if (err) + return err; + } + break; + } + default: + break; + } + return 0; } -static struct btf *btf_load_raw(const char *path) +int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx) { - struct btf *btf; - size_t read_cnt; - struct stat st; - void *data; - FILE *f; - - if (stat(path, &st)) - return ERR_PTR(-errno); + const struct btf_ext_info *seg; + struct btf_ext_info_sec *sec; + int i, err; - data = malloc(st.st_size); - if (!data) - return ERR_PTR(-ENOMEM); + seg = &btf_ext->func_info; + for_each_btf_ext_sec(seg, sec) { + struct bpf_func_info_min *rec; - f = fopen(path, "rb"); - if (!f) { - btf = ERR_PTR(-errno); - goto cleanup; + for_each_btf_ext_rec(seg, sec, i, rec) { + err = visit(&rec->type_id, ctx); + if (err < 0) + return err; + } } - read_cnt = fread(data, 1, st.st_size, f); - fclose(f); - if (read_cnt < st.st_size) { - btf = ERR_PTR(-EBADF); - goto cleanup; - } + seg = &btf_ext->core_relo_info; + for_each_btf_ext_sec(seg, sec) { + struct bpf_core_relo *rec; - btf = btf__new(data, read_cnt); + for_each_btf_ext_rec(seg, sec, i, rec) { + err = visit(&rec->type_id, ctx); + if (err < 0) + return err; + } + } -cleanup: - free(data); - return btf; + return 0; } -/* - * Probe few well-known locations for vmlinux kernel image and try to load BTF - * data out of it to use for target BTF. - */ -struct btf *libbpf_find_kernel_btf(void) +int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx) { - struct { - const char *path_fmt; - bool raw_btf; - } locations[] = { - /* try canonical vmlinux BTF through sysfs first */ - { "/sys/kernel/btf/vmlinux", true /* raw BTF */ }, - /* fall back to trying to find vmlinux ELF on disk otherwise */ - { "/boot/vmlinux-%1$s" }, - { "/lib/modules/%1$s/vmlinux-%1$s" }, - { "/lib/modules/%1$s/build/vmlinux" }, - { "/usr/lib/modules/%1$s/kernel/vmlinux" }, - { "/usr/lib/debug/boot/vmlinux-%1$s" }, - { "/usr/lib/debug/boot/vmlinux-%1$s.debug" }, - { "/usr/lib/debug/lib/modules/%1$s/vmlinux" }, - }; - char path[PATH_MAX + 1]; - struct utsname buf; - struct btf *btf; - int i; + const struct btf_ext_info *seg; + struct btf_ext_info_sec *sec; + int i, err; - uname(&buf); + seg = &btf_ext->func_info; + for_each_btf_ext_sec(seg, sec) { + err = visit(&sec->sec_name_off, ctx); + if (err) + return err; + } - for (i = 0; i < ARRAY_SIZE(locations); i++) { - snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release); + seg = &btf_ext->line_info; + for_each_btf_ext_sec(seg, sec) { + struct bpf_line_info_min *rec; - if (access(path, R_OK)) - continue; + err = visit(&sec->sec_name_off, ctx); + if (err) + return err; - if (locations[i].raw_btf) - btf = btf_load_raw(path); - else - btf = btf__parse_elf(path, NULL); + for_each_btf_ext_rec(seg, sec, i, rec) { + err = visit(&rec->file_name_off, ctx); + if (err) + return err; + err = visit(&rec->line_off, ctx); + if (err) + return err; + } + } - pr_debug("loading kernel BTF '%s': %ld\n", - path, IS_ERR(btf) ? PTR_ERR(btf) : 0); - if (IS_ERR(btf)) - continue; + seg = &btf_ext->core_relo_info; + for_each_btf_ext_sec(seg, sec) { + struct bpf_core_relo *rec; - return btf; + err = visit(&sec->sec_name_off, ctx); + if (err) + return err; + + for_each_btf_ext_rec(seg, sec, i, rec) { + err = visit(&rec->access_str_off, ctx); + if (err) + return err; + } } - pr_warn("failed to find valid kernel BTF\n"); - return ERR_PTR(-ESRCH); + return 0; } |