On 30/08/2022 00:18, Hao Luo wrote:
> Support dumping info of a cgroup_iter link. This includes
> showing the cgroup's id and the order for walking the cgroup
> hierarchy. Example output is as follows:
>
>> bpftool link show
> 1: iter prog 2 target_name bpf_map
> 2: iter prog 3 target_name bpf_prog
> 3: iter prog 12 target_name cgroup cgroup_id 72 order self_only
>
>> bpftool -p link show
> [{
> "id": 1,
> "type": "iter",
> "prog_id": 2,
> "target_name": "bpf_map"
> },{
> "id": 2,
> "type": "iter",
> "prog_id": 3,
> "target_name": "bpf_prog"
> },{
> "id": 3,
> "type": "iter",
> "prog_id": 12,
> "target_name": "cgroup",
> "cgroup_id": 72,
> "order": "self_only"
> }
> ]
>
> Signed-off-by: Hao Luo <haoluo@xxxxxxxxxx>
> ---
> tools/bpf/bpftool/link.c | 35 +++++++++++++++++++++++++++++++++++
> 1 file changed, 35 insertions(+)
>
> diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
> index 7a20931c3250..9e8d14d0114d 100644
> --- a/tools/bpf/bpftool/link.c
> +++ b/tools/bpf/bpftool/link.c
> @@ -83,6 +83,29 @@ static bool is_iter_map_target(const char *target_name)
> strcmp(target_name, "bpf_sk_storage_map") == 0;
> }
>
> +static bool is_iter_cgroup_target(const char *target_name)
> +{
> + return strcmp(target_name, "cgroup") == 0;
> +}
> +
> +static const char *cgroup_order_string(__u32 order)
> +{
> + switch (order) {
> + case BPF_CGROUP_ITER_ORDER_UNSPEC:
> + return "order_unspec";
> + case BPF_CGROUP_ITER_SELF_ONLY:
> + return "self_only";
> + case BPF_CGROUP_ITER_DESCENDANTS_PRE:
> + return "descendants_pre";
> + case BPF_CGROUP_ITER_DESCENDANTS_POST:
> + return "descendants_post";
> + case BPF_CGROUP_ITER_ANCESTORS_UP:
> + return "ancestors_up";
> + default: /* won't happen */
> + return "";
I wonder if that one should be "unknown", in case another option is
added in the future, so we can spot it and address it?
> + }
> +}
> +
> static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr)
> {
> const char *target_name = u64_to_ptr(info->iter.target_name);
> @@ -91,6 +114,12 @@ static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr)
>
> if (is_iter_map_target(target_name))
> jsonw_uint_field(wtr, "map_id", info->iter.map.map_id);
> +
> + if (is_iter_cgroup_target(target_name)) {
> + jsonw_lluint_field(wtr, "cgroup_id", info->iter.cgroup.cgroup_id);
> + jsonw_string_field(wtr, "order",
> + cgroup_order_string(info->iter.cgroup.order));
> + }
> }
>
> static int get_prog_info(int prog_id, struct bpf_prog_info *info)
> @@ -208,6 +237,12 @@ static void show_iter_plain(struct bpf_link_info *info)
>
> if (is_iter_map_target(target_name))
> printf("map_id %u ", info->iter.map.map_id);
> +
> + if (is_iter_cgroup_target(target_name)) {
> + printf("cgroup_id %llu ", info->iter.cgroup.cgroup_id);
> + printf("order %s ",
> + cgroup_order_string(info->iter.cgroup.order));
> + }
> }
>
> static int show_link_close_plain(int fd, struct bpf_link_info *info)
Looks good to me, thank you!
Reviewed-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
