Commit 1c97f6af authored by Martin Kelly's avatar Martin Kelly Committed by Andrii Nakryiko
Browse files

libbpf: Add ring_buffer__ring 



Add a new function ring_buffer__ring, which exposes struct ring * to the
user, representing a single ringbuffer.

Signed-off-by: default avatarMartin Kelly <martin.kelly@crowdstrike.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230925215045.2375758-4-martin.kelly@crowdstrike.com
parent ef3b8200

tools/lib/bpf/libbpf.h

+15 −0
Original line number Diff line number Diff line
@@ -1229,6 +1229,7 @@ LIBBPF_API int bpf_tc_query(const struct bpf_tc_hook *hook, 


/* Ring buffer APIs */

struct ring_buffer;

struct ring;

struct user_ring_buffer;



typedef int (*ring_buffer_sample_fn)(void *ctx, void *data, size_t size);
@@ -1249,6 +1250,20 @@ LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms); 
LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);

LIBBPF_API int ring_buffer__epoll_fd(const struct ring_buffer *rb);



/**

 * @brief **ring_buffer__ring()** returns the ringbuffer object inside a given

 * ringbuffer manager representing a single BPF_MAP_TYPE_RINGBUF map instance.

 *

 * @param rb A ringbuffer manager object.

 * @param idx An index into the ringbuffers contained within the ringbuffer

 * manager object. The index is 0-based and corresponds to the order in which

 * ring_buffer__add was called.

 * @return A ringbuffer object on success; NULL and errno set if the index is

 * invalid.

 */

LIBBPF_API struct ring *ring_buffer__ring(struct ring_buffer *rb,

					  unsigned int idx);



struct user_ring_buffer_opts {

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

};

tools/lib/bpf/libbpf.map

+1 −0
Original line number Diff line number Diff line
@@ -400,4 +400,5 @@ LIBBPF_1.3.0 { 
		bpf_program__attach_netfilter;

		bpf_program__attach_tcx;

		bpf_program__attach_uprobe_multi;

		ring_buffer__ring;

} LIBBPF_1.2.0;

tools/lib/bpf/ringbuf.c

+8 −0
Original line number Diff line number Diff line
@@ -330,6 +330,14 @@ int ring_buffer__epoll_fd(const struct ring_buffer *rb) 
	return rb->epoll_fd;

}



struct ring *ring_buffer__ring(struct ring_buffer *rb, unsigned int idx)

{

	if (idx >= rb->ring_cnt)

		return errno = ERANGE, NULL;



	return rb->rings[idx];

}



static void user_ringbuf_unmap_ring(struct user_ring_buffer *rb)

{

	if (rb->consumer_pos) {