diff options
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/lib/bpf/btf.c | 310 | ||||
| -rw-r--r-- | tools/lib/bpf/btf.h | 7 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.map | 2 |
3 files changed, 255 insertions, 64 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index c25f49fad5a6..e1dbd766c698 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> @@ -27,8 +28,13 @@ static struct btf_type btf_void; struct btf { + /* 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 @@ -153,9 +159,19 @@ static int btf_add_type_idx_entry(struct btf *btf, __u32 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->raw_size < sizeof(struct btf_header)) { @@ -163,21 +179,19 @@ static int btf_parse_hdr(struct btf *btf) return -EINVAL; } - if (hdr->magic != BTF_MAGIC) { + 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 (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->raw_size - sizeof(*hdr); if (!meta_left) { pr_debug("BTF has no data\n"); @@ -224,7 +238,7 @@ static int btf_parse_str_sec(struct btf *btf) 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)) { @@ -257,12 +271,83 @@ static int btf_type_size(const struct btf_type *t) } } +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_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: + 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_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; + default: + pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t)); + return -EINVAL; + } +} + static int btf_parse_type_sec(struct btf *btf) { struct btf_header *hdr = btf->hdr; void *next_type = btf->types_data; void *end_type = next_type + hdr->type_len; - int err, type_size; + int err, i, type_size; /* VOID (type_id == 0) is specially handled by btf__get_type_by_id(), * so ensure we can never properly use its offset from index by @@ -272,19 +357,36 @@ static int btf_parse_type_sec(struct btf *btf) if (err) return err; - while (next_type < end_type) { - err = btf_add_type_idx_entry(btf, next_type - btf->types_data); - if (err) - return err; + while (next_type + sizeof(struct btf_type) <= end_type) { + i++; + + if (btf->swapped_endian) + btf_bswap_type_base(next_type); type_size = btf_type_size(next_type); if (type_size < 0) return type_size; + if (next_type + type_size > end_type) { + pr_warn("BTF type [%d] is malformed\n", i); + 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; } @@ -373,6 +475,38 @@ int btf__set_pointer_size(struct btf *btf, size_t ptr_sz) return 0; } +static bool is_host_big_endian(void) +{ +#if __BYTE_ORDER == __LITTLE_ENDIAN + return false; +#elif __BYTE_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 -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) { return t == &btf_void || btf_is_fwd(t); @@ -561,6 +695,7 @@ void btf__free(struct btf *btf) free(btf->strs_data); } free(btf->raw_data); + free(btf->raw_data_swapped); free(btf->type_offs); free(btf); } @@ -572,8 +707,10 @@ struct btf *btf__new_empty(void) btf = calloc(1, sizeof(*btf)); if (!btf) return ERR_PTR(-ENOMEM); + btf->fd = -1; btf->ptr_sz = sizeof(void *); + btf->swapped_endian = false; /* +1 for empty string at offset 0 */ btf->raw_size = sizeof(struct btf_header) + 1; @@ -604,8 +741,6 @@ struct btf *btf__new(const void *data, __u32 size) if (!btf) return ERR_PTR(-ENOMEM); - btf->fd = -1; - btf->raw_data = malloc(size); if (!btf->raw_data) { err = -ENOMEM; @@ -624,6 +759,10 @@ struct btf *btf__new(const void *data, __u32 size) err = btf_parse_str_sec(btf); err = err ?: btf_parse_type_sec(btf); + if (err) + goto done; + + btf->fd = -1; done: if (err) { @@ -634,17 +773,6 @@ done: return btf; } -static bool btf_check_endianness(const GElf_Ehdr *ehdr) -{ -#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 -} - struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) { Elf_Data *btf_data = NULL, *btf_ext_data = NULL; @@ -677,10 +805,6 @@ 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"); - goto done; - } if (!elf_rawdata(elf_getscn(elf, ehdr.e_shstrndx), NULL)) { pr_warn("failed to get e_shstrndx from %s\n", path); goto done; @@ -792,7 +916,7 @@ struct btf *btf__parse_raw(const char *path) err = -EIO; goto err_out; } - if (magic != BTF_MAGIC) { + if (magic != BTF_MAGIC && magic != bswap_16(BTF_MAGIC)) { /* definitely not a raw BTF */ err = -EPROTO; goto err_out; @@ -942,11 +1066,13 @@ int btf__finalize_data(struct bpf_object *obj, struct btf *btf) return err; } +static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian); + int btf__load(struct btf *btf) { __u32 log_buf_size = 0, raw_size; char *log_buf = NULL; - const void *raw_data; + void *raw_data; int err = 0; if (btf->fd >= 0) @@ -961,11 +1087,14 @@ retry_load: *log_buf = 0; } - raw_data = btf__get_raw_data(btf, &raw_size); + raw_data = btf_get_raw_data(btf, &raw_size, false); if (!raw_data) { err = -ENOMEM; goto done; } + /* cache native raw data representation */ + btf->raw_size = raw_size; + btf->raw_data = raw_data; btf->fd = bpf_load_btf(raw_data, raw_size, log_buf, log_buf_size, false); if (btf->fd < 0) { @@ -998,31 +1127,73 @@ void btf__set_fd(struct btf *btf, int fd) btf->fd = fd; } -const void *btf__get_raw_data(const struct btf *btf_ro, __u32 *size) +static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian) { - struct btf *btf = (struct btf *)btf_ro; + struct btf_header *hdr = btf->hdr; + struct btf_type *t; + void *data, *p; + __u32 data_sz; + int i; - if (!btf->raw_data) { - struct btf_header *hdr = btf->hdr; - void *data; + 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 = 1; 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, hdr->str_len); + p += hdr->str_len; - btf->raw_size = hdr->hdr_len + hdr->type_len + hdr->str_len; - btf->raw_data = calloc(1, btf->raw_size); - if (!btf->raw_data) - return NULL; - data = btf->raw_data; + *size = data_sz; + return data; +err_out: + free(data); + return NULL; +} - memcpy(data, hdr, hdr->hdr_len); - data += hdr->hdr_len; +const void *btf__get_raw_data(const struct btf *btf_ro, __u32 *size) +{ + struct btf *btf = (struct btf *)btf_ro; + __u32 data_sz; + void *data; - memcpy(data, btf->types_data, hdr->type_len); - data += hdr->type_len; + data = btf_get_raw_data(btf, &data_sz, btf->swapped_endian); + if (!data) + return NULL; - memcpy(data, btf->strs_data, hdr->str_len); - data += hdr->str_len; - } - *size = btf->raw_size; - return btf->raw_data; + btf->raw_size = data_sz; + if (btf->swapped_endian) + btf->raw_data_swapped = data; + else + btf->raw_data = data; + *size = data_sz; + return data; } const char *btf__str_by_offset(const struct btf *btf, __u32 offset) @@ -1190,6 +1361,18 @@ static bool strs_hash_equal_fn(const void *key1, const void *key2, void *ctx) return strcmp(str1, str2) == 0; } +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. @@ -1203,10 +1386,7 @@ static int btf_ensure_modifiable(struct btf *btf) if (btf_is_modifiable(btf)) { /* any BTF modification invalidates raw_data */ - if (btf->raw_data) { - free(btf->raw_data); - btf->raw_data = NULL; - } + btf_invalidate_raw_data(btf); return 0; } @@ -1254,8 +1434,7 @@ static int btf_ensure_modifiable(struct btf *btf) btf->strs_deduped = btf->hdr->str_len <= 1; /* invalidate raw_data representation */ - free(btf->raw_data); - btf->raw_data = NULL; + btf_invalidate_raw_data(btf); return 0; @@ -2275,7 +2454,10 @@ 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; } diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index f7dec0144c3c..57247240a20a 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -25,6 +25,11 @@ struct btf_type; struct bpf_object; +enum btf_endianness { + BTF_LITTLE_ENDIAN = 0, + BTF_BIG_ENDIAN = 1, +}; + LIBBPF_API void btf__free(struct btf *btf); LIBBPF_API struct btf *btf__new(const void *data, __u32 size); LIBBPF_API struct btf *btf__new_empty(void); @@ -42,6 +47,8 @@ LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 id); LIBBPF_API size_t btf__pointer_size(const struct btf *btf); LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz); +LIBBPF_API enum btf_endianness btf__endianness(const struct btf *btf); +LIBBPF_API int btf__set_endianness(struct btf *btf, enum btf_endianness endian); LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id); LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id); LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id); diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 6b10ebad69c6..f7a8ff37ef04 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -325,8 +325,10 @@ LIBBPF_0.2.0 { btf__add_union; btf__add_var; btf__add_volatile; + btf__endianness; btf__find_str; btf__new_empty; + btf__set_endianness; btf__str_by_offset; perf_buffer__buffer_cnt; perf_buffer__buffer_fd; |