It is useful to print map ID on successful creation.
JSON case:
$ ./bpftool -j map create /sys/fs/bpf/test_map4 type hash key 4 value 8 entries
128 name map4
{"id":12}
Generic case:
$ ./bpftool map create /sys/fs/bpf/test_map5 type hash key 4 value 8 entries
128 name map5
Map successfully created with ID: 15
Bpftool Issue: https://github.com/libbpf/bpftool/issues/121
Acked-by: Yonghong Song <[email protected]>
Reviewed-by: Quentin Monnet <[email protected]>
Signed-off-by: Harshit Mogalapalli <[email protected]>
---
v2->v3: remove a line break("\n" ) in p_err statement. [Thanks Quentin]
---
tools/bpf/bpftool/map.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index c9de44a45778..f32ae5476d76 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -1251,6 +1251,8 @@ static int do_create(int argc, char **argv)
LIBBPF_OPTS(bpf_map_create_opts, attr);
enum bpf_map_type map_type = BPF_MAP_TYPE_UNSPEC;
__u32 key_size = 0, value_size = 0, max_entries = 0;
+ struct bpf_map_info map_info = {};
+ __u32 map_info_len = sizeof(map_info);
const char *map_name = NULL;
const char *pinfile;
int err = -1, fd;
@@ -1353,13 +1355,24 @@ static int do_create(int argc, char **argv)
}
err = do_pin_fd(fd, pinfile);
- close(fd);
if (err)
- goto exit;
+ goto close_fd;
- if (json_output)
- jsonw_null(json_wtr);
+ err = bpf_obj_get_info_by_fd(fd, &map_info, &map_info_len);
+ if (err) {
+ p_err("Failed to fetch map info: %s", strerror(errno));
+ goto close_fd;
+ }
+ if (json_output) {
+ jsonw_start_object(json_wtr);
+ jsonw_int_field(json_wtr, "id", map_info.id);
+ jsonw_end_object(json_wtr);
+ } else {
+ printf("Map successfully created with ID: %u\n", map_info.id);
+ }
+close_fd:
+ close(fd);
exit:
if (attr.inner_map_fd > 0)
close(attr.inner_map_fd);
--
2.50.1
