Hi Quentin,
On 01/11/25 22:29, Quentin Monnet wrote:
2025-10-30 14:06 UTC-0700 ~ Harshit Mogalapalli
<[email protected]>
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
Signed-off-by: Harshit Mogalapalli <[email protected]>
---
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..80c96b33b553 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\n", strerror(errno));
Nit: Please remove the line break ('\n') here, p_err() already adds it.
Ah thanks for spotting that, will do.
+ 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);
I've been wondering if we should have some parent object like
'{"map_created": { "id": 15 }}' in case we later add more output, but I
can't really see a good use case at the moment, I'm probably
overthinking it... So I'm good with the current output. Thanks for this!
Thanks a lot for the review.
With the line break removed:
Sure will send a next version with updates to p_err and selftest(to not
echo messages on success)
Reviewed-by: Quentin Monnet <[email protected]>
Regards,
Harshit
