diff options
Diffstat (limited to 'tools/lib/bpf/btf.c')
| -rw-r--r-- | tools/lib/bpf/btf.c | 1054 |
1 files changed, 767 insertions, 287 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index ee95fd379d4d..48c66f3a9200 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -22,6 +22,7 @@ #include "libbpf_internal.h" #include "hashmap.h" #include "strset.h" +#include "str_error.h" #define BTF_MAX_NR_TYPES 0x7fffffffU #define BTF_MAX_STR_OFFSET 0x7fffffffU @@ -116,6 +117,9 @@ struct btf { /* whether strings are already deduplicated */ bool strs_deduped; + /* whether base_btf should be freed in btf_free for this instance */ + bool owns_base; + /* BTF object FD, if loaded into kernel */ int fd; @@ -279,7 +283,7 @@ static int btf_parse_str_sec(struct btf *btf) return -EINVAL; } if (!btf->base_btf && start[0]) { - pr_debug("Invalid BTF string section\n"); + pr_debug("Malformed BTF string section, did you forget to provide base BTF?\n"); return -EINVAL; } return 0; @@ -598,7 +602,7 @@ static int btf_sanity_check(const struct btf *btf) __u32 i, n = btf__type_cnt(btf); int err; - for (i = 1; i < n; i++) { + for (i = btf->start_id; i < n; i++) { t = btf_type_by_id(btf, i); err = btf_validate_type(btf, t, i); if (err) @@ -969,6 +973,8 @@ void btf__free(struct btf *btf) free(btf->raw_data); free(btf->raw_data_swapped); free(btf->type_offs); + if (btf->owns_base) + btf__free(btf->base_btf); free(btf); } @@ -991,6 +997,7 @@ static struct btf *btf_new_empty(struct btf *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->swapped_endian = base_btf->swapped_endian; } /* +1 for empty string at offset 0 */ @@ -1079,53 +1086,43 @@ struct btf *btf__new(const void *data, __u32 size) return libbpf_ptr(btf_new(data, size, NULL)); } -static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, - struct btf_ext **btf_ext) +struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf) +{ + return libbpf_ptr(btf_new(data, size, base_btf)); +} + +struct btf_elf_secs { + Elf_Data *btf_data; + Elf_Data *btf_ext_data; + Elf_Data *btf_base_data; +}; + +static int btf_find_elf_sections(Elf *elf, const char *path, struct btf_elf_secs *secs) { - Elf_Data *btf_data = NULL, *btf_ext_data = NULL; - int err = 0, fd = -1, idx = 0; - struct btf *btf = NULL; Elf_Scn *scn = NULL; - Elf *elf = NULL; + Elf_Data *data; GElf_Ehdr ehdr; size_t shstrndx; + int idx = 0; - 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 | O_CLOEXEC); - if (fd < 0) { - err = -errno; - pr_warn("failed to open %s: %s\n", path, strerror(errno)); - return ERR_PTR(err); - } - - err = -LIBBPF_ERRNO__FORMAT; - - elf = elf_begin(fd, ELF_C_READ, NULL); - if (!elf) { - pr_warn("failed to open %s as ELF file\n", path); - goto done; - } if (!gelf_getehdr(elf, &ehdr)) { pr_warn("failed to get EHDR from %s\n", path); - goto done; + goto err; } if (elf_getshdrstrndx(elf, &shstrndx)) { pr_warn("failed to get section names section index for %s\n", path); - goto done; + goto err; } if (!elf_rawdata(elf_getscn(elf, shstrndx), NULL)) { pr_warn("failed to get e_shstrndx from %s\n", path); - goto done; + goto err; } while ((scn = elf_nextscn(elf, scn)) != NULL) { + Elf_Data **field; GElf_Shdr sh; char *name; @@ -1133,42 +1130,103 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, if (gelf_getshdr(scn, &sh) != &sh) { pr_warn("failed to get section(%d) header from %s\n", idx, path); - goto done; + goto err; } name = elf_strptr(elf, shstrndx, sh.sh_name); if (!name) { pr_warn("failed to get section(%d) name from %s\n", idx, path); - goto done; + goto err; } - if (strcmp(name, BTF_ELF_SEC) == 0) { - btf_data = elf_getdata(scn, 0); - if (!btf_data) { - pr_warn("failed to get section(%d, %s) data from %s\n", - idx, name, path); - goto done; - } - continue; - } else if (btf_ext && strcmp(name, BTF_EXT_ELF_SEC) == 0) { - btf_ext_data = elf_getdata(scn, 0); - if (!btf_ext_data) { - pr_warn("failed to get section(%d, %s) data from %s\n", - idx, name, path); - goto done; - } + + if (strcmp(name, BTF_ELF_SEC) == 0) + field = &secs->btf_data; + else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) + field = &secs->btf_ext_data; + else if (strcmp(name, BTF_BASE_ELF_SEC) == 0) + field = &secs->btf_base_data; + else continue; + + data = elf_getdata(scn, 0); + if (!data) { + pr_warn("failed to get section(%d, %s) data from %s\n", + idx, name, path); + goto err; } + *field = data; + } + + return 0; + +err: + return -LIBBPF_ERRNO__FORMAT; +} + +static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, + struct btf_ext **btf_ext) +{ + struct btf_elf_secs secs = {}; + struct btf *dist_base_btf = NULL; + struct btf *btf = NULL; + int err = 0, fd = -1; + Elf *elf = NULL; + + 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 | O_CLOEXEC); + if (fd < 0) { + err = -errno; + pr_warn("failed to open %s: %s\n", path, errstr(err)); + return ERR_PTR(err); + } + + elf = elf_begin(fd, ELF_C_READ, NULL); + if (!elf) { + err = -LIBBPF_ERRNO__FORMAT; + pr_warn("failed to open %s as ELF file\n", path); + goto done; } - if (!btf_data) { + err = btf_find_elf_sections(elf, path, &secs); + if (err) + goto done; + + if (!secs.btf_data) { pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path); err = -ENODATA; goto done; } - btf = btf_new(btf_data->d_buf, btf_data->d_size, base_btf); - err = libbpf_get_error(btf); - if (err) + + if (secs.btf_base_data) { + dist_base_btf = btf_new(secs.btf_base_data->d_buf, secs.btf_base_data->d_size, + NULL); + if (IS_ERR(dist_base_btf)) { + err = PTR_ERR(dist_base_btf); + dist_base_btf = NULL; + goto done; + } + } + + btf = btf_new(secs.btf_data->d_buf, secs.btf_data->d_size, + dist_base_btf ?: base_btf); + if (IS_ERR(btf)) { + err = PTR_ERR(btf); goto done; + } + if (dist_base_btf && base_btf) { + err = btf__relocate(btf, base_btf); + if (err) + goto done; + btf__free(dist_base_btf); + dist_base_btf = NULL; + } + + if (dist_base_btf) + btf->owns_base = true; switch (gelf_getclass(elf)) { case ELFCLASS32: @@ -1182,11 +1240,12 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, break; } - if (btf_ext && btf_ext_data) { - *btf_ext = btf_ext__new(btf_ext_data->d_buf, btf_ext_data->d_size); - err = libbpf_get_error(*btf_ext); - if (err) + if (btf_ext && secs.btf_ext_data) { + *btf_ext = btf_ext__new(secs.btf_ext_data->d_buf, secs.btf_ext_data->d_size); + if (IS_ERR(*btf_ext)) { + err = PTR_ERR(*btf_ext); goto done; + } } else if (btf_ext) { *btf_ext = NULL; } @@ -1200,6 +1259,7 @@ done: if (btf_ext) btf_ext__free(*btf_ext); + btf__free(dist_base_btf); btf__free(btf); return ERR_PTR(err); @@ -1317,7 +1377,9 @@ struct btf *btf__parse_split(const char *path, struct btf *base_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) +int btf_load_into_kernel(struct btf *btf, + char *log_buf, size_t log_sz, __u32 log_level, + int token_fd) { LIBBPF_OPTS(bpf_btf_load_opts, opts); __u32 buf_sz = 0, raw_size; @@ -1367,6 +1429,10 @@ retry_load: opts.log_level = log_level; } + opts.token_fd = token_fd; + if (token_fd) + opts.btf_flags |= BPF_F_TOKEN_FD; + btf->fd = bpf_btf_load(raw_data, raw_size, &opts); if (btf->fd < 0) { /* time to turn on verbose mode and try again */ @@ -1381,7 +1447,7 @@ retry_load: goto retry_load; err = -errno; - pr_warn("BTF loading error: %d\n", err); + pr_warn("BTF loading error: %s\n", errstr(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); @@ -1394,7 +1460,7 @@ done: int btf__load_into_kernel(struct btf *btf) { - return btf_load_into_kernel(btf, NULL, 0, 0); + return btf_load_into_kernel(btf, NULL, 0, 0, 0); } int btf__fd(const struct btf *btf) @@ -1728,9 +1794,8 @@ struct btf_pipe { struct hashmap *str_off_map; /* map string offsets from src to dst */ }; -static int btf_rewrite_str(__u32 *str_off, void *ctx) +static int btf_rewrite_str(struct btf_pipe *p, __u32 *str_off) { - struct btf_pipe *p = ctx; long mapped_off; int off, err; @@ -1760,10 +1825,11 @@ static int btf_rewrite_str(__u32 *str_off, void *ctx) return 0; } -int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type) +static int btf_add_type(struct btf_pipe *p, const struct btf_type *src_type) { - struct btf_pipe p = { .src = src_btf, .dst = btf }; + struct btf_field_iter it; struct btf_type *t; + __u32 *str_off; int sz, err; sz = btf_type_size(src_type); @@ -1771,35 +1837,33 @@ int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_t return libbpf_err(sz); /* deconstruct BTF, if necessary, and invalidate raw_data */ - if (btf_ensure_modifiable(btf)) + if (btf_ensure_modifiable(p->dst)) return libbpf_err(-ENOMEM); - t = btf_add_type_mem(btf, sz); + t = btf_add_type_mem(p->dst, sz); if (!t) return libbpf_err(-ENOMEM); memcpy(t, src_type, sz); - err = btf_type_visit_str_offs(t, btf_rewrite_str, &p); + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS); if (err) return libbpf_err(err); - return btf_commit_type(btf, sz); + while ((str_off = btf_field_iter_next(&it))) { + err = btf_rewrite_str(p, str_off); + if (err) + return libbpf_err(err); + } + + return btf_commit_type(p->dst, sz); } -static int btf_rewrite_type_ids(__u32 *type_id, void *ctx) +int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type) { - struct btf *btf = ctx; - - if (!*type_id) /* nothing to do for VOID references */ - return 0; + struct btf_pipe p = { .src = src_btf, .dst = btf }; - /* 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; + return btf_add_type(&p, src_type); } static size_t btf_dedup_identity_hash_fn(long key, void *ctx); @@ -1847,6 +1911,9 @@ int btf__add_btf(struct btf *btf, const struct btf *src_btf) memcpy(t, src_btf->types_data, data_sz); for (i = 0; i < cnt; i++) { + struct btf_field_iter it; + __u32 *type_id, *str_off; + sz = btf_type_size(t); if (sz < 0) { /* unlikely, has to be corrupted src_btf */ @@ -1858,15 +1925,31 @@ int btf__add_btf(struct btf *btf, const struct btf *src_btf) *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); + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS); if (err) goto err_out; + while ((str_off = btf_field_iter_next(&it))) { + err = btf_rewrite_str(&p, str_off); + 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); + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); if (err) goto err_out; + while ((type_id = btf_field_iter_next(&it))) { + if (!*type_id) /* nothing to do for VOID references */ + continue; + + /* 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; + } + /* go to next type data and type offset index entry */ t += sz; off++; @@ -2804,7 +2887,7 @@ int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id, return btf_commit_type(btf, sz); } -struct btf_ext_sec_setup_param { +struct btf_ext_sec_info_param { __u32 off; __u32 len; __u32 min_rec_size; @@ -2812,14 +2895,20 @@ struct btf_ext_sec_setup_param { const char *desc; }; -static int btf_ext_setup_info(struct btf_ext *btf_ext, - struct btf_ext_sec_setup_param *ext_sec) +/* + * Parse a single info subsection of the BTF.ext info data: + * - validate subsection structure and elements + * - save info subsection start and sizing details in struct btf_ext + * - endian-independent operation, for calling before byte-swapping + */ +static int btf_ext_parse_sec_info(struct btf_ext *btf_ext, + struct btf_ext_sec_info_param *ext_sec, + bool is_native) { 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; if (ext_sec->len == 0) @@ -2831,6 +2920,7 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext, return -EINVAL; } + /* The start of the info sec (including the __u32 record_size). */ info = btf_ext->data + btf_ext->hdr->hdr_len + ext_sec->off; info_left = ext_sec->len; @@ -2846,9 +2936,13 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext, return -EINVAL; } - /* The record size needs to meet the minimum standard */ - record_size = *(__u32 *)info; + /* The record size needs to meet either the minimum standard or, when + * handling non-native endianness data, the exact standard so as + * to allow safe byte-swapping. + */ + record_size = is_native ? *(__u32 *)info : bswap_32(*(__u32 *)info); if (record_size < ext_sec->min_rec_size || + (!is_native && record_size != ext_sec->min_rec_size) || record_size & 0x03) { pr_debug("%s section in .BTF.ext has invalid record size %u\n", ext_sec->desc, record_size); @@ -2860,7 +2954,7 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext, /* If no records, return failure now so .BTF.ext won't be used. */ if (!info_left) { - pr_debug("%s section in .BTF.ext has no records", ext_sec->desc); + pr_debug("%s section in .BTF.ext has no records\n", ext_sec->desc); return -EINVAL; } @@ -2875,7 +2969,7 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext, return -EINVAL; } - num_records = sinfo->num_info; + num_records = is_native ? sinfo->num_info : bswap_32(sinfo->num_info); if (num_records == 0) { pr_debug("%s section has incorrect num_records in .BTF.ext\n", ext_sec->desc); @@ -2903,64 +2997,157 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext, return 0; } -static int btf_ext_setup_func_info(struct btf_ext *btf_ext) +/* Parse all info secs in the BTF.ext info data */ +static int btf_ext_parse_info(struct btf_ext *btf_ext, bool is_native) { - struct btf_ext_sec_setup_param param = { + struct btf_ext_sec_info_param func_info = { .off = btf_ext->hdr->func_info_off, .len = btf_ext->hdr->func_info_len, .min_rec_size = sizeof(struct bpf_func_info_min), .ext_info = &btf_ext->func_info, .desc = "func_info" }; - - return btf_ext_setup_info(btf_ext, ¶m); -} - -static int btf_ext_setup_line_info(struct btf_ext *btf_ext) -{ - struct btf_ext_sec_setup_param param = { + struct btf_ext_sec_info_param line_info = { .off = btf_ext->hdr->line_info_off, .len = btf_ext->hdr->line_info_len, .min_rec_size = sizeof(struct bpf_line_info_min), .ext_info = &btf_ext->line_info, .desc = "line_info", }; - - return btf_ext_setup_info(btf_ext, ¶m); -} - -static int btf_ext_setup_core_relos(struct btf_ext *btf_ext) -{ - struct btf_ext_sec_setup_param param = { + struct btf_ext_sec_info_param core_relo = { .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", }; + int err; - return btf_ext_setup_info(btf_ext, ¶m); + err = btf_ext_parse_sec_info(btf_ext, &func_info, is_native); + if (err) + return err; + + err = btf_ext_parse_sec_info(btf_ext, &line_info, is_native); + if (err) + return err; + + if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) + return 0; /* skip core relos parsing */ + + err = btf_ext_parse_sec_info(btf_ext, &core_relo, is_native); + if (err) + return err; + + return 0; +} + +/* Swap byte-order of BTF.ext header with any endianness */ +static void btf_ext_bswap_hdr(struct btf_ext_header *h) +{ + bool is_native = h->magic == BTF_MAGIC; + __u32 hdr_len; + + hdr_len = is_native ? h->hdr_len : bswap_32(h->hdr_len); + + h->magic = bswap_16(h->magic); + h->hdr_len = bswap_32(h->hdr_len); + h->func_info_off = bswap_32(h->func_info_off); + h->func_info_len = bswap_32(h->func_info_len); + h->line_info_off = bswap_32(h->line_info_off); + h->line_info_len = bswap_32(h->line_info_len); + + if (hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) + return; + + h->core_relo_off = bswap_32(h->core_relo_off); + h->core_relo_len = bswap_32(h->core_relo_len); +} + +/* Swap byte-order of generic info subsection */ +static void btf_ext_bswap_info_sec(void *info, __u32 len, bool is_native, + info_rec_bswap_fn bswap_fn) +{ + struct btf_ext_info_sec *sec; + __u32 info_left, rec_size, *rs; + + if (len == 0) + return; + + rs = info; /* info record size */ + rec_size = is_native ? *rs : bswap_32(*rs); + *rs = bswap_32(*rs); + + sec = info + sizeof(__u32); /* info sec #1 */ + info_left = len - sizeof(__u32); + while (info_left) { + unsigned int sec_hdrlen = sizeof(struct btf_ext_info_sec); + __u32 i, num_recs; + void *p; + + num_recs = is_native ? sec->num_info : bswap_32(sec->num_info); + sec->sec_name_off = bswap_32(sec->sec_name_off); + sec->num_info = bswap_32(sec->num_info); + p = sec->data; /* info rec #1 */ + for (i = 0; i < num_recs; i++, p += rec_size) + bswap_fn(p); + sec = p; + info_left -= sec_hdrlen + (__u64)rec_size * num_recs; + } +} + +/* + * Swap byte-order of all info data in a BTF.ext section + * - requires BTF.ext hdr in native endianness + */ +static void btf_ext_bswap_info(struct btf_ext *btf_ext, void *data) +{ + const bool is_native = btf_ext->swapped_endian; + const struct btf_ext_header *h = data; + void *info; + + /* Swap func_info subsection byte-order */ + info = data + h->hdr_len + h->func_info_off; + btf_ext_bswap_info_sec(info, h->func_info_len, is_native, + (info_rec_bswap_fn)bpf_func_info_bswap); + + /* Swap line_info subsection byte-order */ + info = data + h->hdr_len + h->line_info_off; + btf_ext_bswap_info_sec(info, h->line_info_len, is_native, + (info_rec_bswap_fn)bpf_line_info_bswap); + + /* Swap core_relo subsection byte-order (if present) */ + if (h->hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) + return; + + info = data + h->hdr_len + h->core_relo_off; + btf_ext_bswap_info_sec(info, h->core_relo_len, is_native, + (info_rec_bswap_fn)bpf_core_relo_bswap); } -static int btf_ext_parse_hdr(__u8 *data, __u32 data_size) +/* Parse hdr data and info sections: check and convert to native endianness */ +static int btf_ext_parse(struct btf_ext *btf_ext) { - const struct btf_ext_header *hdr = (struct btf_ext_header *)data; + __u32 hdr_len, data_size = btf_ext->data_size; + struct btf_ext_header *hdr = btf_ext->hdr; + bool swapped_endian = false; + int err; - if (data_size < offsetofend(struct btf_ext_header, hdr_len) || - data_size < hdr->hdr_len) { - pr_debug("BTF.ext header not found"); + if (data_size < offsetofend(struct btf_ext_header, hdr_len)) { + pr_debug("BTF.ext header too short\n"); return -EINVAL; } + hdr_len = hdr->hdr_len; if (hdr->magic == bswap_16(BTF_MAGIC)) { - pr_warn("BTF.ext in non-native endianness is not supported\n"); - return -ENOTSUP; + swapped_endian = true; + hdr_len = bswap_32(hdr_len); } else if (hdr->magic != BTF_MAGIC) { pr_debug("Invalid BTF.ext magic:%x\n", hdr->magic); return -EINVAL; } - if (hdr->version != BTF_VERSION) { + /* Ensure known version of structs, current BTF_VERSION == 1 */ + if (hdr->version != 1) { pr_debug("Unsupported BTF.ext version:%u\n", hdr->version); return -ENOTSUP; } @@ -2970,11 +3157,39 @@ static int btf_ext_parse_hdr(__u8 *data, __u32 data_size) return -ENOTSUP; } - if (data_size == hdr->hdr_len) { + if (data_size < hdr_len) { + pr_debug("BTF.ext header not found\n"); + return -EINVAL; + } else if (data_size == hdr_len) { pr_debug("BTF.ext has no data\n"); return -EINVAL; } + /* Verify mandatory hdr info details present */ + if (hdr_len < offsetofend(struct btf_ext_header, line_info_len)) { + pr_warn("BTF.ext header missing func_info, line_info\n"); + return -EINVAL; + } + + /* Keep hdr native byte-order in memory for introspection */ + if (swapped_endian) + btf_ext_bswap_hdr(btf_ext->hdr); + + /* Validate info subsections and cache key metadata */ + err = btf_ext_parse_info(btf_ext, !swapped_endian); + if (err) + return err; + + /* Keep infos native byte-order in memory for introspection */ + if (swapped_endian) + btf_ext_bswap_info(btf_ext, btf_ext->data); + + /* + * Set btf_ext->swapped_endian only after all header and info data has + * been swapped, helping bswap functions determine if their data are + * in native byte-order when called. + */ + btf_ext->swapped_endian = swapped_endian; return 0; } @@ -2986,6 +3201,7 @@ void btf_ext__free(struct btf_ext *btf_ext) free(btf_ext->line_info.sec_idxs); free(btf_ext->core_relo_info.sec_idxs); free(btf_ext->data); + free(btf_ext->data_swapped); free(btf_ext); } @@ -3006,29 +3222,7 @@ struct btf_ext *btf_ext__new(const __u8 *data, __u32 size) } memcpy(btf_ext->data, data, size); - 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; - - err = btf_ext_setup_line_info(btf_ext); - if (err) - goto done; - - 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; + err = btf_ext_parse(btf_ext); done: if (err) { @@ -3039,10 +3233,65 @@ done: return btf_ext; } -const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size) +static void *btf_ext_raw_data(const struct btf_ext *btf_ext_ro, bool swap_endian) { + struct btf_ext *btf_ext = (struct btf_ext *)btf_ext_ro; + const __u32 data_sz = btf_ext->data_size; + void *data; + + /* Return native data (always present) or swapped data if present */ + if (!swap_endian) + return btf_ext->data; + else if (btf_ext->data_swapped) + return btf_ext->data_swapped; + + /* Recreate missing swapped data, then cache and return */ + data = calloc(1, data_sz); + if (!data) + return NULL; + memcpy(data, btf_ext->data, data_sz); + + btf_ext_bswap_info(btf_ext, data); + btf_ext_bswap_hdr(data); + btf_ext->data_swapped = data; + return data; +} + +const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size) +{ + void *data; + + data = btf_ext_raw_data(btf_ext, btf_ext->swapped_endian); + if (!data) + return errno = ENOMEM, NULL; + *size = btf_ext->data_size; - return btf_ext->data; + return data; +} + +__attribute__((alias("btf_ext__raw_data"))) +const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size); + +enum btf_endianness btf_ext__endianness(const struct btf_ext *btf_ext) +{ + if (is_host_big_endian()) + return btf_ext->swapped_endian ? BTF_LITTLE_ENDIAN : BTF_BIG_ENDIAN; + else + return btf_ext->swapped_endian ? BTF_BIG_ENDIAN : BTF_LITTLE_ENDIAN; +} + +int btf_ext__set_endianness(struct btf_ext *btf_ext, enum btf_endianness endian) +{ + if (endian != BTF_LITTLE_ENDIAN && endian != BTF_BIG_ENDIAN) + return libbpf_err(-EINVAL); + + btf_ext->swapped_endian = is_host_big_endian() != (endian == BTF_BIG_ENDIAN); + + if (!btf_ext->swapped_endian) { + free(btf_ext->data_swapped); + btf_ext->data_swapped = NULL; + } + return 0; } struct btf_dedup; @@ -3206,7 +3455,7 @@ int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts) d = btf_dedup_new(btf, opts); if (IS_ERR(d)) { - pr_debug("btf_dedup_new failed: %ld", PTR_ERR(d)); + pr_debug("btf_dedup_new failed: %ld\n", PTR_ERR(d)); return libbpf_err(-EINVAL); } @@ -3217,42 +3466,42 @@ int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts) err = btf_dedup_prep(d); if (err) { - pr_debug("btf_dedup_prep failed:%d\n", err); + pr_debug("btf_dedup_prep failed: %s\n", errstr(err)); goto done; } err = btf_dedup_strings(d); if (err < 0) { - pr_debug("btf_dedup_strings failed:%d\n", err); + pr_debug("btf_dedup_strings failed: %s\n", errstr(err)); goto done; } err = btf_dedup_prim_types(d); if (err < 0) { - pr_debug("btf_dedup_prim_types failed:%d\n", err); + pr_debug("btf_dedup_prim_types failed: %s\n", errstr(err)); goto done; } err = btf_dedup_struct_types(d); if (err < 0) { - pr_debug("btf_dedup_struct_types failed:%d\n", err); + pr_debug("btf_dedup_struct_types failed: %s\n", errstr(err)); goto done; } err = btf_dedup_resolve_fwds(d); if (err < 0) { - pr_debug("btf_dedup_resolve_fwds failed:%d\n", err); + pr_debug("btf_dedup_resolve_fwds failed: %s\n", errstr(err)); goto done; } err = btf_dedup_ref_types(d); if (err < 0) { - pr_debug("btf_dedup_ref_types failed:%d\n", err); + pr_debug("btf_dedup_ref_types failed: %s\n", errstr(err)); goto done; } err = btf_dedup_compact_types(d); if (err < 0) { - pr_debug("btf_dedup_compact_types failed:%d\n", err); + pr_debug("btf_dedup_compact_types failed: %s\n", errstr(err)); goto done; } err = btf_dedup_remap_types(d); if (err < 0) { - pr_debug("btf_dedup_remap_types failed:%d\n", err); + pr_debug("btf_dedup_remap_types failed: %s\n", errstr(err)); goto done; } @@ -3300,7 +3549,7 @@ struct btf_dedup { struct strset *strs_set; }; -static long hash_combine(long h, long value) +static unsigned long hash_combine(unsigned long h, unsigned long value) { return h * 31 + value; } @@ -3438,11 +3687,19 @@ static int btf_for_each_str_off(struct btf_dedup *d, str_off_visit_fn fn, void * int i, r; for (i = 0; i < d->btf->nr_types; i++) { + struct btf_field_iter it; struct btf_type *t = btf_type_by_id(d->btf, d->btf->start_id + i); + __u32 *str_off; - r = btf_type_visit_str_offs(t, fn, ctx); + r = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS); if (r) return r; + + while ((str_off = btf_field_iter_next(&it))) { + r = fn(str_off, ctx); + if (r) + return r; + } } if (!d->btf_ext) @@ -4099,7 +4356,7 @@ static bool btf_dedup_identical_structs(struct btf_dedup *d, __u32 id1, __u32 id * and canonical graphs are not compatible structurally, whole graphs are * incompatible. If types are structurally equivalent (i.e., all information * except referenced type IDs is exactly the same), a mapping from `canon_id` to - * a `cand_id` is recored in hypothetical mapping (`btf_dedup->hypot_map`). + * a `cand_id` is recoded in hypothetical mapping (`btf_dedup->hypot_map`). * If a type references other types, then those referenced types are checked * for equivalence recursively. * @@ -4137,7 +4394,7 @@ static bool btf_dedup_identical_structs(struct btf_dedup *d, __u32 id1, __u32 id * consists of portions of the graph that come from multiple compilation units. * This is due to the fact that types within single compilation unit are always * deduplicated and FWDs are already resolved, if referenced struct/union - * definiton is available. So, if we had unresolved FWD and found corresponding + * definition is available. So, if we had unresolved FWD and found corresponding * STRUCT/UNION, they will be from different compilation units. This * consequently means that when we "link" FWD to corresponding STRUCT/UNION, * type graph will likely have at least two different BTF types that describe @@ -4904,10 +5161,23 @@ static int btf_dedup_remap_types(struct btf_dedup *d) for (i = 0; i < d->btf->nr_types; i++) { struct btf_type *t = btf_type_by_id(d->btf, d->btf->start_id + i); + struct btf_field_iter it; + __u32 *type_id; - r = btf_type_visit_type_ids(t, btf_dedup_remap_type_id, d); + r = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); if (r) return r; + + while ((type_id = btf_field_iter_next(&it))) { + __u32 resolved_id, new_id; + + resolved_id = resolve_type_id(d, *type_id); + new_id = d->hypot_map[resolved_id]; + if (new_id > BTF_MAX_NR_TYPES) + return -EINVAL; + + *type_id = new_id; + } } if (!d->btf_ext) @@ -4926,10 +5196,9 @@ static int btf_dedup_remap_types(struct btf_dedup *d) */ struct btf *btf__load_vmlinux_btf(void) { + const char *sysfs_btf_path = "/sys/kernel/btf/vmlinux"; + /* fall back locations, trying to find vmlinux on disk */ 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", @@ -4943,8 +5212,24 @@ struct btf *btf__load_vmlinux_btf(void) struct btf *btf; int i, err; - uname(&buf); + /* is canonical sysfs location accessible? */ + if (faccessat(AT_FDCWD, sysfs_btf_path, F_OK, AT_EACCESS) < 0) { + pr_warn("kernel BTF is missing at '%s', was CONFIG_DEBUG_INFO_BTF enabled?\n", + sysfs_btf_path); + } else { + btf = btf__parse(sysfs_btf_path, NULL); + if (!btf) { + err = -errno; + pr_warn("failed to read kernel BTF from '%s': %s\n", + sysfs_btf_path, errstr(err)); + return libbpf_err_ptr(err); + } + pr_debug("loaded kernel BTF from '%s'\n", sysfs_btf_path); + return btf; + } + /* try fallback locations */ + uname(&buf); for (i = 0; i < ARRAY_SIZE(locations); i++) { snprintf(path, PATH_MAX, locations[i], buf.release); @@ -4953,7 +5238,7 @@ struct btf *btf__load_vmlinux_btf(void) btf = btf__parse(path, NULL); err = libbpf_get_error(btf); - pr_debug("loading kernel BTF '%s': %d\n", path, err); + pr_debug("loading kernel BTF '%s': %s\n", path, errstr(err)); if (err) continue; @@ -4974,136 +5259,6 @@ struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_bt 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: - case BTF_KIND_ENUM64: - return 0; - - 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_VAR: - case BTF_KIND_DECL_TAG: - case BTF_KIND_TYPE_TAG: - return visit(&t->type, ctx); - - case BTF_KIND_ARRAY: { - struct btf_array *a = btf_array(t); - - 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 *m = btf_members(t); - - for (i = 0, n = btf_vlen(t); i < n; i++, m++) { - err = visit(&m->type, ctx); - if (err) - return err; - } - return 0; - } - - case BTF_KIND_FUNC_PROTO: { - struct btf_param *m = btf_params(t); - - 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; - } - return 0; - } - - case BTF_KIND_DATASEC: { - struct btf_var_secinfo *m = btf_var_secinfos(t); - - for (i = 0, n = btf_vlen(t); i < n; i++, m++) { - err = visit(&m->type, ctx); - if (err) - return err; - } - return 0; - } - - default: - return -EINVAL; - } -} - -int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx) -{ - int i, n, err; - - 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; -} - int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx) { const struct btf_ext_info *seg; @@ -5183,3 +5338,328 @@ int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void return 0; } + +struct btf_distill { + struct btf_pipe pipe; + int *id_map; + unsigned int split_start_id; + unsigned int split_start_str; + int diff_id; +}; + +static int btf_add_distilled_type_ids(struct btf_distill *dist, __u32 i) +{ + struct btf_type *split_t = btf_type_by_id(dist->pipe.src, i); + struct btf_field_iter it; + __u32 *id; + int err; + + err = btf_field_iter_init(&it, split_t, BTF_FIELD_ITER_IDS); + if (err) + return err; + while ((id = btf_field_iter_next(&it))) { + struct btf_type *base_t; + + if (!*id) + continue; + /* split BTF id, not needed */ + if (*id >= dist->split_start_id) + continue; + /* already added ? */ + if (dist->id_map[*id] > 0) + continue; + + /* only a subset of base BTF types should be referenced from + * split BTF; ensure nothing unexpected is referenced. + */ + base_t = btf_type_by_id(dist->pipe.src, *id); + switch (btf_kind(base_t)) { + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_FWD: + case BTF_KIND_ARRAY: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_TYPEDEF: + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + case BTF_KIND_PTR: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_VOLATILE: + case BTF_KIND_FUNC_PROTO: + case BTF_KIND_TYPE_TAG: + dist->id_map[*id] = *id; + break; + default: + pr_warn("unexpected reference to base type[%u] of kind [%u] when creating distilled base BTF.\n", + *id, btf_kind(base_t)); + return -EINVAL; + } + /* If a base type is used, ensure types it refers to are + * marked as used also; so for example if we find a PTR to INT + * we need both the PTR and INT. + * + * The only exception is named struct/unions, since distilled + * base BTF composite types have no members. + */ + if (btf_is_composite(base_t) && base_t->name_off) + continue; + err = btf_add_distilled_type_ids(dist, *id); + if (err) + return err; + } + return 0; +} + +static int btf_add_distilled_types(struct btf_distill *dist) +{ + bool adding_to_base = dist->pipe.dst->start_id == 1; + int id = btf__type_cnt(dist->pipe.dst); + struct btf_type *t; + int i, err = 0; + + + /* Add types for each of the required references to either distilled + * base or split BTF, depending on type characteristics. + */ + for (i = 1; i < dist->split_start_id; i++) { + const char *name; + int kind; + + if (!dist->id_map[i]) + continue; + t = btf_type_by_id(dist->pipe.src, i); + kind = btf_kind(t); + name = btf__name_by_offset(dist->pipe.src, t->name_off); + + switch (kind) { + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_FWD: + /* Named int, float, fwd are added to base. */ + if (!adding_to_base) + continue; + err = btf_add_type(&dist->pipe, t); + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + /* Named struct/union are added to base as 0-vlen + * struct/union of same size. Anonymous struct/unions + * are added to split BTF as-is. + */ + if (adding_to_base) { + if (!t->name_off) + continue; + err = btf_add_composite(dist->pipe.dst, kind, name, t->size); + } else { + if (t->name_off) + continue; + err = btf_add_type(&dist->pipe, t); + } + break; + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + /* Named enum[64]s are added to base as a sized + * enum; relocation will match with appropriately-named + * and sized enum or enum64. + * + * Anonymous enums are added to split BTF as-is. + */ + if (adding_to_base) { + if (!t->name_off) + continue; + err = btf__add_enum(dist->pipe.dst, name, t->size); + } else { + if (t->name_off) + continue; + err = btf_add_type(&dist->pipe, t); + } + break; + case BTF_KIND_ARRAY: + case BTF_KIND_TYPEDEF: + case BTF_KIND_PTR: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_VOLATILE: + case BTF_KIND_FUNC_PROTO: + case BTF_KIND_TYPE_TAG: + /* All other types are added to split BTF. */ + if (adding_to_base) + continue; + err = btf_add_type(&dist->pipe, t); + break; + default: + pr_warn("unexpected kind when adding base type '%s'[%u] of kind [%u] to distilled base BTF.\n", + name, i, kind); + return -EINVAL; + + } + if (err < 0) + break; + dist->id_map[i] = id++; + } + return err; +} + +/* Split BTF ids without a mapping will be shifted downwards since distilled + * base BTF is smaller than the original base BTF. For those that have a + * mapping (either to base or updated split BTF), update the id based on + * that mapping. + */ +static int btf_update_distilled_type_ids(struct btf_distill *dist, __u32 i) +{ + struct btf_type *t = btf_type_by_id(dist->pipe.dst, i); + struct btf_field_iter it; + __u32 *id; + int err; + + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); + if (err) + return err; + while ((id = btf_field_iter_next(&it))) { + if (dist->id_map[*id]) + *id = dist->id_map[*id]; + else if (*id >= dist->split_start_id) + *id -= dist->diff_id; + } + return 0; +} + +/* Create updated split BTF with distilled base BTF; distilled base BTF + * consists of BTF information required to clarify the types that split + * BTF refers to, omitting unneeded details. Specifically it will contain + * base types and memberless definitions of named structs, unions and enumerated + * types. Associated reference types like pointers, arrays and anonymous + * structs, unions and enumerated types will be added to split BTF. + * Size is recorded for named struct/unions to help guide matching to the + * target base BTF during later relocation. + * + * The only case where structs, unions or enumerated types are fully represented + * is when they are anonymous; in such cases, the anonymous type is added to + * split BTF in full. + * + * We return newly-created split BTF where the split BTF refers to a newly-created + * distilled base BTF. Both must be freed separately by the caller. + */ +int btf__distill_base(const struct btf *src_btf, struct btf **new_base_btf, + struct btf **new_split_btf) +{ + struct btf *new_base = NULL, *new_split = NULL; + const struct btf *old_base; + unsigned int n = btf__type_cnt(src_btf); + struct btf_distill dist = {}; + struct btf_type *t; + int i, err = 0; + + /* src BTF must be split BTF. */ + old_base = btf__base_btf(src_btf); + if (!new_base_btf || !new_split_btf || !old_base) + return libbpf_err(-EINVAL); + + new_base = btf__new_empty(); + if (!new_base) + return libbpf_err(-ENOMEM); + + btf__set_endianness(new_base, btf__endianness(src_btf)); + + dist.id_map = calloc(n, sizeof(*dist.id_map)); + if (!dist.id_map) { + err = -ENOMEM; + goto done; + } + dist.pipe.src = src_btf; + dist.pipe.dst = new_base; + dist.pipe.str_off_map = hashmap__new(btf_dedup_identity_hash_fn, btf_dedup_equal_fn, NULL); + if (IS_ERR(dist.pipe.str_off_map)) { + err = -ENOMEM; + goto done; + } + dist.split_start_id = btf__type_cnt(old_base); + dist.split_start_str = old_base->hdr->str_len; + + /* Pass over src split BTF; generate the list of base BTF type ids it + * references; these will constitute our distilled BTF set to be + * distributed over base and split BTF as appropriate. + */ + for (i = src_btf->start_id; i < n; i++) { + err = btf_add_distilled_type_ids(&dist, i); + if (err < 0) + goto done; + } + /* Next add types for each of the required references to base BTF and split BTF + * in turn. + */ + err = btf_add_distilled_types(&dist); + if (err < 0) + goto done; + + /* Create new split BTF with distilled base BTF as its base; the final + * state is split BTF with distilled base BTF that represents enough + * about its base references to allow it to be relocated with the base + * BTF available. + */ + new_split = btf__new_empty_split(new_base); + if (!new_split) { + err = -errno; + goto done; + } + dist.pipe.dst = new_split; + /* First add all split types */ + for (i = src_btf->start_id; i < n; i++) { + t = btf_type_by_id(src_btf, i); + err = btf_add_type(&dist.pipe, t); + if (err < 0) + goto done; + } + /* Now add distilled types to split BTF that are not added to base. */ + err = btf_add_distilled_types(&dist); + if (err < 0) + goto done; + + /* All split BTF ids will be shifted downwards since there are less base + * BTF ids in distilled base BTF. + */ + dist.diff_id = dist.split_start_id - btf__type_cnt(new_base); + + n = btf__type_cnt(new_split); + /* Now update base/split BTF ids. */ + for (i = 1; i < n; i++) { + err = btf_update_distilled_type_ids(&dist, i); + if (err < 0) + break; + } +done: + free(dist.id_map); + hashmap__free(dist.pipe.str_off_map); + if (err) { + btf__free(new_split); + btf__free(new_base); + return libbpf_err(err); + } + *new_base_btf = new_base; + *new_split_btf = new_split; + + return 0; +} + +const struct btf_header *btf_header(const struct btf *btf) +{ + return btf->hdr; +} + +void btf_set_base_btf(struct btf *btf, const struct btf *base_btf) +{ + btf->base_btf = (struct btf *)base_btf; + btf->start_id = btf__type_cnt(base_btf); + btf->start_str_off = base_btf->hdr->str_len; +} + +int btf__relocate(struct btf *btf, const struct btf *base_btf) +{ + int err = btf_relocate(btf, base_btf, NULL); + + if (!err) + btf->owns_base = false; + return libbpf_err(err); +} |