Commit cd31039a authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

tools/libbpf: Add support for bpf map element iterator 



Add map_fd to bpf_iter_attach_opts and flags to
bpf_link_create_opts. Later on, bpftool or selftest
will be able to create a bpf map element iterator
by passing map_fd to the kernel during link
creation time.

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723184117.590673-1-yhs@fb.com
parent 5ce6e77c

tools/lib/bpf/bpf.c

+1 −0
Original line number Diff line number Diff line
@@ -598,6 +598,7 @@ int bpf_link_create(int prog_fd, int target_fd, 
	attr.link_create.prog_fd = prog_fd;

	attr.link_create.target_fd = target_fd;

	attr.link_create.attach_type = attach_type;

	attr.link_create.flags = OPTS_GET(opts, flags, 0);



	return sys_bpf(BPF_LINK_CREATE, &attr, sizeof(attr));

}

tools/lib/bpf/bpf.h

+2 −1
Original line number Diff line number Diff line
@@ -170,8 +170,9 @@ LIBBPF_API int bpf_prog_detach2(int prog_fd, int attachable_fd, 


struct bpf_link_create_opts {

	size_t sz; /* size of this struct for forward/backward compatibility */

	__u32 flags;

};

#define bpf_link_create_opts__last_field sz

#define bpf_link_create_opts__last_field flags



LIBBPF_API int bpf_link_create(int prog_fd, int target_fd,

			       enum bpf_attach_type attach_type,

tools/lib/bpf/libbpf.c

+9 −1
Original line number Diff line number Diff line
@@ -8282,13 +8282,20 @@ struct bpf_link * 
bpf_program__attach_iter(struct bpf_program *prog,

			 const struct bpf_iter_attach_opts *opts)

{

	DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);

	char errmsg[STRERR_BUFSIZE];

	struct bpf_link *link;

	int prog_fd, link_fd;

	__u32 target_fd = 0;



	if (!OPTS_VALID(opts, bpf_iter_attach_opts))

		return ERR_PTR(-EINVAL);



	if (OPTS_HAS(opts, map_fd)) {

		target_fd = opts->map_fd;

		link_create_opts.flags = BPF_ITER_LINK_MAP_FD;

	}



	prog_fd = bpf_program__fd(prog);

	if (prog_fd < 0) {

		pr_warn("program '%s': can't attach before loaded\n",
@@ -8301,7 +8308,8 @@ bpf_program__attach_iter(struct bpf_program *prog, 
		return ERR_PTR(-ENOMEM);

	link->detach = &bpf_link__detach_fd;



	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_ITER, NULL);

	link_fd = bpf_link_create(prog_fd, target_fd, BPF_TRACE_ITER,

				  &link_create_opts);

	if (link_fd < 0) {

		link_fd = -errno;

		free(link);

tools/lib/bpf/libbpf.h

+2 −1
Original line number Diff line number Diff line
@@ -264,8 +264,9 @@ LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map); 


struct bpf_iter_attach_opts {

	size_t sz; /* size of this struct for forward/backward compatibility */

	__u32 map_fd;

};

#define bpf_iter_attach_opts__last_field sz

#define bpf_iter_attach_opts__last_field map_fd



LIBBPF_API struct bpf_link *

bpf_program__attach_iter(struct bpf_program *prog,