libbpf: introduce concept of bpf_link (1c2e9efc) · Commits · 戴 / test

bpf_link is an abstraction of an association of a BPF program and one of many possible BPF attachment points (hooks). This allows to have uniform interface for detaching BPF programs regardless of the nature of link and how it was created. Details of creation and setting up of a specific bpf_link is handled by corresponding attachment methods (bpf_program__attach_xxx) added in subsequent commits. Once successfully created, bpf_link has to be eventually destroyed with bpf_link__destroy(), at which point BPF program is disassociated from a hook and all the relevant resources are freed. Signed-off-by:

Andrii Nakryiko <andriin@fb.com> Acked-by:

Song Liu <songliubraving@fb.com> Reviewed-by:

Stanislav Fomichev <sdf@google.com> Signed-off-by:

Daniel Borkmann <daniel@iogearbox.net>

tools/lib/bpf/libbpf.c

+17 −0

Original line number	Diff line number	Diff line
		@@ -3941,6 +3941,23 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
		return 0;
		}

		struct bpf_link {
		int (destroy)(struct bpf_link link);
		};

		int bpf_link__destroy(struct bpf_link *link)
		{
		int err;

		if (!link)
		return 0;

		err = link->destroy(link);
		free(link);

		return err;
		}

		enum bpf_perf_event_ret
		bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
		void *copy_mem, size_t copy_size,

tools/lib/bpf/libbpf.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -165,6 +165,10 @@ LIBBPF_API int bpf_program__pin(struct bpf_program prog, const char path);
		LIBBPF_API int bpf_program__unpin(struct bpf_program prog, const char path);
		LIBBPF_API void bpf_program__unload(struct bpf_program *prog);

		struct bpf_link;

		LIBBPF_API int bpf_link__destroy(struct bpf_link *link);

		struct bpf_insn;

		/*

tools/lib/bpf/libbpf.map

+2 −1

Original line number	Diff line number	Diff line
		@@ -167,10 +167,11 @@ LIBBPF_0.0.3 {

		LIBBPF_0.0.4 {
		global:
		bpf_link__destroy;
		bpf_object__load_xattr;
		btf_dump__dump_type;
		btf_dump__free;
		btf_dump__new;
		btf__parse_elf;
		bpf_object__load_xattr;
		libbpf_num_possible_cpus;
		} LIBBPF_0.0.3;

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