[PATCH bpf-next v2 05/10] bpftool: Output io_uring iterator info

[Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>]

Output the sole field related to io_uring iterator (inode of attached
io_uring) so that it can be useful in informational and also debugging
cases (trying to find actual io_uring fd attached to the iterator).

Output:
89: iter  prog 262  target_name io_uring_file  io_uring_inode 16764
	pids test_progs(384)

[
  {
    "id": 123,
    "type": "iter",
    "prog_id": 463,
    "target_name": "io_uring_buf",
    "io_uring_inode": 16871,
    "pids": [
      {
        "pid": 443,
        "comm": "test_progs"
      }
    ]
  }
]

[
  {
    "id": 126,
    "type": "iter",
    "prog_id": 483,
    "target_name": "io_uring_file",
    "io_uring_inode": 16887,
    "pids": [
      {
        "pid": 448,
        "comm": "test_progs"
      }
    ]
  }
]

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
---
 tools/bpf/bpftool/link.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index 2c258db0d352..409ae861b839 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -86,6 +86,12 @@ static bool is_iter_map_target(const char *target_name)
 	       strcmp(target_name, "bpf_sk_storage_map") == 0;
 }
 
+static bool is_iter_io_uring_target(const char *target_name)
+{
+	return strcmp(target_name, "io_uring_file") == 0 ||
+	       strcmp(target_name, "io_uring_buf") == 0;
+}
+
 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);
@@ -94,6 +100,8 @@ 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);
+	else if (is_iter_io_uring_target(target_name))
+		jsonw_uint_field(wtr, "io_uring_inode", info->iter.io_uring.inode);
 }
 
 static int get_prog_info(int prog_id, struct bpf_prog_info *info)
@@ -204,6 +212,8 @@ 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);
+	else if (is_iter_io_uring_target(target_name))
+		printf("io_uring_inode %llu  ", info->iter.io_uring.inode);
 }
 
 static int show_link_close_plain(int fd, struct bpf_link_info *info)
-- 
2.34.0