[RFC PATCH bpf-next v4 07/12] libbpf: Support passing user-defined flags for struct_ops

[Hui Zhu <hui.zhu@linux.dev>]

From: Hui Zhu <zhuhui@kylinos.cn>

Building on the previous change that added flags to the kernel's link
creation path, this patch exposes this functionality through libbpf.

The `bpf_struct_ops_opts` struct is extended with a `flags` member,
which is then passed to the `bpf_link_create` syscall within
`bpf_map__attach_struct_ops_opts`.

This enables userspace applications to pass flags, such as
`BPF_F_ALLOW_OVERRIDE`, when attaching struct_ops to cgroups,
providing more control over the attachment behavior in nested
hierarchies.

Signed-off-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Hui Zhu <zhuhui@kylinos.cn>
---
 tools/lib/bpf/libbpf.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 70a00da54ff5..06c936bad211 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -13511,6 +13511,7 @@ struct bpf_link *bpf_map__attach_struct_ops_opts(const struct bpf_map *map,
 	}
 
 	link_opts.cgroup.relative_fd = OPTS_GET(opts, relative_fd, 0);
+	link_opts.flags = OPTS_GET(opts, flags, 0);
 
 	fd = bpf_link_create(map->fd, 0, BPF_STRUCT_OPS, &link_opts);
 	if (fd < 0) {
-- 
2.43.0