From ae4ab4b4117d23da49f04a7e1fe82a41e6074eeb Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 8 Feb 2019 11:19:38 -0800 Subject: btf: expose API to work with raw btf_ext data This patch changes struct btf_ext to retain original data in sequential block of memory, which makes it possible to expose btf_ext__get_raw_data() interface similar to btf__get_raw_data(), allowing users of libbpf to get access to raw representation of .BTF.ext section. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/btf.c | 102 +++++++++++++++++++++++++---------------------- tools/lib/bpf/btf.h | 2 + tools/lib/bpf/libbpf.map | 1 + 3 files changed, 57 insertions(+), 48 deletions(-) (limited to 'tools') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 4fba0aa989df..f6b724ed1bdd 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -42,9 +42,8 @@ struct btf { struct btf_ext_info { /* - * info points to a deep copy of the individual info section - * (e.g. func_info and line_info) from the .BTF.ext. - * It does not include the __u32 rec_size. + * info points to the individual info section (e.g. func_info and + * line_info) from the .BTF.ext. It does not include the __u32 rec_size. */ void *info; __u32 rec_size; @@ -52,8 +51,13 @@ struct btf_ext_info { }; struct btf_ext { + union { + struct btf_ext_header *hdr; + void *data; + }; struct btf_ext_info func_info; struct btf_ext_info line_info; + __u32 data_size; }; struct btf_ext_info_sec { @@ -596,7 +600,7 @@ int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, return 0; } -struct btf_ext_sec_copy_param { +struct btf_ext_sec_setup_param { __u32 off; __u32 len; __u32 min_rec_size; @@ -604,20 +608,14 @@ struct btf_ext_sec_copy_param { const char *desc; }; -static int btf_ext_copy_info(struct btf_ext *btf_ext, - __u8 *data, __u32 data_size, - struct btf_ext_sec_copy_param *ext_sec) +static int btf_ext_setup_info(struct btf_ext *btf_ext, + struct btf_ext_sec_setup_param *ext_sec) { - const struct btf_ext_header *hdr = (struct btf_ext_header *)data; const struct btf_ext_info_sec *sinfo; struct btf_ext_info *ext_info; __u32 info_left, record_size; /* The start of the info sec (including the __u32 record_size). */ - const void *info; - - /* data and data_size do not include btf_ext_header from now on */ - data = data + hdr->hdr_len; - data_size -= hdr->hdr_len; + void *info; if (ext_sec->off & 0x03) { pr_debug(".BTF.ext %s section is not aligned to 4 bytes\n", @@ -625,16 +623,15 @@ static int btf_ext_copy_info(struct btf_ext *btf_ext, return -EINVAL; } - if (data_size < ext_sec->off || - ext_sec->len > data_size - ext_sec->off) { + info = btf_ext->data + btf_ext->hdr->hdr_len + ext_sec->off; + info_left = ext_sec->len; + + if (btf_ext->data + btf_ext->data_size < info + ext_sec->len) { pr_debug("%s section (off:%u len:%u) is beyond the end of the ELF section .BTF.ext\n", - ext_sec->desc, ext_sec->off, ext_sec->len); + ext_sec->desc, ext_sec->off, ext_sec->len); return -EINVAL; } - info = data + ext_sec->off; - info_left = ext_sec->len; - /* At least a record size */ if (info_left < sizeof(__u32)) { pr_debug(".BTF.ext %s record size not found\n", ext_sec->desc); @@ -646,7 +643,7 @@ static int btf_ext_copy_info(struct btf_ext *btf_ext, if (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); + ext_sec->desc, record_size); return -EINVAL; } @@ -692,42 +689,35 @@ static int btf_ext_copy_info(struct btf_ext *btf_ext, ext_info = ext_sec->ext_info; ext_info->len = ext_sec->len - sizeof(__u32); ext_info->rec_size = record_size; - ext_info->info = malloc(ext_info->len); - if (!ext_info->info) - return -ENOMEM; - memcpy(ext_info->info, info + sizeof(__u32), ext_info->len); + ext_info->info = info + sizeof(__u32); return 0; } -static int btf_ext_copy_func_info(struct btf_ext *btf_ext, - __u8 *data, __u32 data_size) +static int btf_ext_setup_func_info(struct btf_ext *btf_ext) { - const struct btf_ext_header *hdr = (struct btf_ext_header *)data; - struct btf_ext_sec_copy_param param = { - .off = hdr->func_info_off, - .len = hdr->func_info_len, + struct btf_ext_sec_setup_param param = { + .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_copy_info(btf_ext, data, data_size, ¶m); + return btf_ext_setup_info(btf_ext, ¶m); } -static int btf_ext_copy_line_info(struct btf_ext *btf_ext, - __u8 *data, __u32 data_size) +static int btf_ext_setup_line_info(struct btf_ext *btf_ext) { - const struct btf_ext_header *hdr = (struct btf_ext_header *)data; - struct btf_ext_sec_copy_param param = { - .off = hdr->line_info_off, - .len = hdr->line_info_len, + struct btf_ext_sec_setup_param param = { + .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_copy_info(btf_ext, data, data_size, ¶m); + return btf_ext_setup_info(btf_ext, ¶m); } static int btf_ext_parse_hdr(__u8 *data, __u32 data_size) @@ -767,9 +757,7 @@ void btf_ext__free(struct btf_ext *btf_ext) { if (!btf_ext) return; - - free(btf_ext->func_info.info); - free(btf_ext->line_info.info); + free(btf_ext->data); free(btf_ext); } @@ -786,13 +774,23 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size) if (!btf_ext) return ERR_PTR(-ENOMEM); - err = btf_ext_copy_func_info(btf_ext, data, size); - if (err) { - btf_ext__free(btf_ext); - return ERR_PTR(err); + btf_ext->data_size = size; + btf_ext->data = malloc(size); + if (!btf_ext->data) { + err = -ENOMEM; + goto done; } + memcpy(btf_ext->data, data, size); + + err = btf_ext_setup_func_info(btf_ext); + if (err) + goto done; - err = btf_ext_copy_line_info(btf_ext, data, size); + err = btf_ext_setup_line_info(btf_ext); + if (err) + goto done; + +done: if (err) { btf_ext__free(btf_ext); return ERR_PTR(err); @@ -801,6 +799,12 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size) return btf_ext; } +const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size) +{ + *size = btf_ext->data_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, @@ -849,7 +853,8 @@ static int btf_ext_reloc_info(const struct btf *btf, return -ENOENT; } -int btf_ext__reloc_func_info(const struct btf *btf, const struct btf_ext *btf_ext, +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) { @@ -857,7 +862,8 @@ int btf_ext__reloc_func_info(const struct btf *btf, const struct btf_ext *btf_ex insns_cnt, func_info, cnt); } -int btf_ext__reloc_line_info(const struct btf *btf, const struct btf_ext *btf_ext, +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) { diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 10fe412461fe..0306b54d54eb 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -78,6 +78,8 @@ LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size); LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext); +LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext* btf_ext, + __u32 *size); LIBBPF_API int btf_ext__reloc_func_info(const struct btf *btf, const struct btf_ext *btf_ext, const char *sec_name, __u32 insns_cnt, diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 9e10467f8cbb..eb78c7c261d9 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -141,6 +141,7 @@ LIBBPF_0.0.2 { btf__load; btf_ext__free; btf_ext__func_info_rec_size; + btf_ext__get_raw_data; btf_ext__line_info_rec_size; btf_ext__new; btf_ext__reloc_func_info; -- cgit v1.2.3-59-g8ed1b