bpf: Implement link_query for bpf iterators

This patch implemented bpf_link callback functions
show_fdinfo and fill_link_info to support link_query
interface.

The general interface for show_fdinfo and fill_link_info
will print/fill the target_name. Each targets can
register show_fdinfo and fill_link_info callbacks
to print/fill more target specific information.

For example, the below is a fdinfo result for a bpf
task iterator.
  $ cat /proc/1749/fdinfo/7
  pos:    0
  flags:  02000000
  mnt_id: 14
  link_type:      iter
  link_id:        11
  prog_tag:       990e1f8152f7e54f
  prog_id:        59
  target_name:    task

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200821184418.574122-1-yhs@fb.com
This commit is contained in:
Yonghong Song
2020-08-21 11:44:18 -07:00
committed by Alexei Starovoitov
parent 149cb33955
commit 6b0a249a30
4 changed files with 78 additions and 0 deletions

View File

@@ -4071,6 +4071,13 @@ struct bpf_link_info {
__u64 cgroup_id;
__u32 attach_type;
} cgroup;
struct {
__aligned_u64 target_name; /* in/out: target_name buffer ptr */
__u32 target_name_len; /* in/out: target_name buffer len */
union {
__u32 map_id;
} map;
} iter;
struct {
__u32 netns_ino;
__u32 attach_type;