bpf: introduce BPF_PROG_QUERY command

introduce BPF_PROG_QUERY command to retrieve a set of either
attached programs to given cgroup or a set of effective programs
that will execute for events within a cgroup

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
for cgroup bits
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 57eb866ae78d..269512b94a94 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5761,4 +5761,14 @@ int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
         mutex_unlock(&cgroup_mutex);
         return ret;
 }
+int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
+                     union bpf_attr __user *uattr)
+{
+        int ret;
+
+        mutex_lock(&cgroup_mutex);
+        ret = __cgroup_bpf_query(cgrp, attr, uattr);
+        mutex_unlock(&cgroup_mutex);
+        return ret;
+}
 #endif /* CONFIG_CGROUP_BPF */