From 96408c43447aff5091a6938f29d8b6f2d0aa2064 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Mon, 4 Feb 2019 11:00:58 -0800 Subject: [PATCH] tools/bpf: implement libbpf btf__get_map_kv_tids() API function Currently, to get map key/value type id's, the macro BPF_ANNOTATE_KV_PAIR(, , ) needs to be defined in the bpf program for the corresponding map. During program/map loading time, the local static function bpf_map_find_btf_info() in libbpf.c is implemented to retrieve the key/value type ids given the map name. The patch refactored function bpf_map_find_btf_info() to create an API btf__get_map_kv_tids() which includes the bulk of implementation for the original function. The API btf__get_map_kv_tids() can be used by bcc, a JIT based bpf compilation system, which uses the same BPF_ANNOTATE_KV_PAIR to record map key/value types. Acked-by: Martin KaFai Lau Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/btf.c | 73 ++++++++++++++++++++++++++++++++++++++++ tools/lib/bpf/btf.h | 4 +++ tools/lib/bpf/libbpf.c | 72 +++++---------------------------------- tools/lib/bpf/libbpf.map | 1 + 4 files changed, 87 insertions(+), 63 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 51a0db05bf80..7ec0463354db 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 #include #include #include @@ -504,6 +505,78 @@ exit_free: return err; } +int btf__get_map_kv_tids(const struct btf *btf, char *map_name, + __u32 expected_key_size, __u32 expected_value_size, + __u32 *key_type_id, __u32 *value_type_id) +{ + 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; + + if (snprintf(container_name, max_name, "____btf_map_%s", map_name) == + max_name) { + pr_warning("map:%s length of '____btf_map_%s' is too long\n", + map_name, map_name); + return -EINVAL; + } + + container_id = btf__find_by_name(btf, container_name); + if (container_id < 0) { + pr_warning("map:%s container_name:%s cannot be found in BTF. Missing BPF_ANNOTATE_KV_PAIR?\n", + map_name, container_name); + return container_id; + } + + container_type = btf__type_by_id(btf, container_id); + if (!container_type) { + pr_warning("map:%s cannot find BTF type for container_id:%u\n", + map_name, container_id); + return -EINVAL; + } + + if (BTF_INFO_KIND(container_type->info) != BTF_KIND_STRUCT || + BTF_INFO_VLEN(container_type->info) < 2) { + pr_warning("map:%s container_name:%s is an invalid container struct\n", + map_name, container_name); + return -EINVAL; + } + + key = (struct btf_member *)(container_type + 1); + value = key + 1; + + key_size = btf__resolve_size(btf, key->type); + if (key_size < 0) { + pr_warning("map:%s invalid BTF key_type_size\n", map_name); + return key_size; + } + + if (expected_key_size != key_size) { + pr_warning("map:%s btf_key_type_size:%u != map_def_key_size:%u\n", + map_name, (__u32)key_size, expected_key_size); + return -EINVAL; + } + + value_size = btf__resolve_size(btf, value->type); + if (value_size < 0) { + pr_warning("map:%s invalid BTF value_type_size\n", map_name); + return value_size; + } + + if (expected_value_size != value_size) { + pr_warning("map:%s btf_value_type_size:%u != map_def_value_size:%u\n", + map_name, (__u32)value_size, expected_value_size); + return -EINVAL; + } + + *key_type_id = key->type; + *value_type_id = value->type; + + return 0; +} + struct btf_ext_sec_copy_param { __u32 off; __u32 len; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 418389e2a662..258c87e9f55d 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -66,6 +66,10 @@ LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id); LIBBPF_API int btf__fd(const struct btf *btf); LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset); LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf); +LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, char *map_name, + __u32 expected_key_size, + __u32 expected_value_size, + __u32 *key_type_id, __u32 *value_type_id); LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size); LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index ce209ab9a1a2..84ca6c2bea91 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1056,72 +1056,18 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr, static int bpf_map_find_btf_info(struct bpf_map *map, const struct btf *btf) { - const struct btf_type *container_type; - const struct btf_member *key, *value; struct bpf_map_def *def = &map->def; - const size_t max_name = 256; - char container_name[max_name]; - __s64 key_size, value_size; - __s32 container_id; - - if (snprintf(container_name, max_name, "____btf_map_%s", map->name) == - max_name) { - pr_warning("map:%s length of '____btf_map_%s' is too long\n", - map->name, map->name); - return -EINVAL; - } - - container_id = btf__find_by_name(btf, container_name); - if (container_id < 0) { - pr_debug("map:%s container_name:%s cannot be found in BTF. Missing BPF_ANNOTATE_KV_PAIR?\n", - map->name, container_name); - return container_id; - } - - container_type = btf__type_by_id(btf, container_id); - if (!container_type) { - pr_warning("map:%s cannot find BTF type for container_id:%u\n", - map->name, container_id); - return -EINVAL; - } - - if (BTF_INFO_KIND(container_type->info) != BTF_KIND_STRUCT || - BTF_INFO_VLEN(container_type->info) < 2) { - pr_warning("map:%s container_name:%s is an invalid container struct\n", - map->name, container_name); - return -EINVAL; - } - - key = (struct btf_member *)(container_type + 1); - value = key + 1; - - key_size = btf__resolve_size(btf, key->type); - if (key_size < 0) { - pr_warning("map:%s invalid BTF key_type_size\n", - map->name); - return key_size; - } - - if (def->key_size != key_size) { - pr_warning("map:%s btf_key_type_size:%u != map_def_key_size:%u\n", - map->name, (__u32)key_size, def->key_size); - return -EINVAL; - } - - value_size = btf__resolve_size(btf, value->type); - if (value_size < 0) { - pr_warning("map:%s invalid BTF value_type_size\n", map->name); - return value_size; - } + __u32 key_type_id, value_type_id; + int ret; - if (def->value_size != value_size) { - pr_warning("map:%s btf_value_type_size:%u != map_def_value_size:%u\n", - map->name, (__u32)value_size, def->value_size); - return -EINVAL; - } + ret = btf__get_map_kv_tids(btf, map->name, def->key_size, + def->value_size, &key_type_id, + &value_type_id); + if (ret) + return ret; - map->btf_key_type_id = key->type; - map->btf_value_type_id = value->type; + map->btf_key_type_id = key_type_id; + map->btf_value_type_id = value_type_id; return 0; } diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 46441c5f030b..7990e857e003 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -133,6 +133,7 @@ LIBBPF_0.0.2 { bpf_map_lookup_elem_flags; bpf_object__find_map_fd_by_name; bpf_get_link_xdp_id; + btf__get_map_kv_tids; btf_ext__free; btf_ext__func_info_rec_size; btf_ext__line_info_rec_size; -- 2.30.2