libbpf: Add internal helper to load BTF data by FD (a19f93cf) · Commits · 戴 / test

tools/lib/bpf/btf.c

+35 −26

Original line number	Diff line number	Diff line
		@@ -1323,35 +1323,27 @@ const char btf__name_by_offset(const struct btf btf, __u32 offset)
		return btf__str_by_offset(btf, offset);
		}

		int btf__get_from_id(__u32 id, struct btf **btf)
		struct btf btf_get_from_fd(int btf_fd, struct btf base_btf)
		{
		struct bpf_btf_info btf_info = { 0 };
		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) {
		@@ -1360,31 +1352,48 @@ 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;
		}

		return err;
		int btf__get_from_id(__u32 id, struct btf **btf)
		{
		struct btf *res;
		int btf_fd;

		*btf = NULL;
		btf_fd = bpf_btf_get_fd_by_id(id);
		if (btf_fd < 0)
		return -errno;

		res = btf_get_from_fd(btf_fd, NULL);
		close(btf_fd);
		if (IS_ERR(res))
		return PTR_ERR(res);

		*btf = res;
		return 0;
		}

		int btf__get_map_kv_tids(const struct btf btf, const char map_name,

tools/lib/bpf/libbpf_internal.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -155,6 +155,7 @@ int bpf_object__section_size(const struct bpf_object obj, const char name,
		__u32 *size);
		int bpf_object__variable_offset(const struct bpf_object obj, const char name,
		__u32 *off);
		struct btf btf_get_from_fd(int btf_fd, struct btf base_btf);

		struct btf_ext_info {
		/*

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