selftests/bpf: Add link detach tests for cgroup, netns, and xdp bpf_links

Add bpf_link__detach() testing to selftests for cgroup, netns, and xdp
bpf_links.

Signed-off-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Song Liu <[email protected]>
Acked-by: John Fastabend <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

1 files changed, 14 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/testing_helpers.c b/tools/testing/selftests/bpf/testing_helpers.c
index 0af6337a8962..800d503e5cb4 100644
--- a/tools/testing/selftests/bpf/testing_helpers.c
+++ b/tools/testing/selftests/bpf/testing_helpers.c
@@ -64,3 +64,17 @@ int parse_num_list(const char *s, bool **num_set, int *num_set_len)
 
 	return 0;
 }
+
+__u32 link_info_prog_id(const struct bpf_link *link, struct bpf_link_info *info)
+{
+	__u32 info_len = sizeof(*info);
+	int err;
+
+	memset(info, 0, sizeof(*info));
+	err = bpf_obj_get_info_by_fd(bpf_link__fd(link), info, &info_len);
+	if (err) {
+		printf("failed to get link info: %d\n", -errno);
+		return 0;
+	}
+	return info->prog_id;
+}