[PATCH bpf-next v2 2/2] tools/bpftool: show btf_id in map listing

[Prashant Bhole]

Let's print btf id of map similar to the way we are printing it
for programs.

Sample output:
user@test# bpftool map -f
61: lpm_trie  flags 0x1
        key 20B  value 8B  max_entries 1  memlock 4096B
133: array  name test_btf_id  flags 0x0
        key 4B  value 4B  max_entries 4  memlock 4096B
        pinned /sys/fs/bpf/test100
        btf_id 174
170: array  name test_btf_id  flags 0x0
        key 4B  value 4B  max_entries 4  memlock 4096B
        btf_id 240

Signed-off-by: Prashant Bhole <bhole_prashant...@lab.ntt.co.jp>
Reviewed-by: Quentin Monnet <quentin.mon...@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicin...@netronome.com>
Acked-by: Song Liu <songliubrav...@fb.com>
---
v2: Add btf_id before pinned filename in show_map_close_json() as
    suggested by Quentin

 tools/bpf/bpftool/map.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index cda0f27fa895..17d379ef0edc 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -538,6 +538,9 @@ static int show_map_close_json(int fd, struct bpf_map_info 
*info)
        }
        close(fd);
 
+       if (info->btf_id)
+               jsonw_int_field(json_wtr, "btf_id", info->btf_id);
+
        if (!hash_empty(map_table.table)) {
                struct pinned_obj *obj;
 
@@ -613,6 +616,9 @@ static int show_map_close_plain(int fd, struct bpf_map_info 
*info)
                }
        }
 
+       if (info->btf_id)
+               printf("\n\tbtf_id %d", info->btf_id);
+
        printf("\n");
        return 0;
 }
-- 
2.17.2