cgroups: add unified_cgroup_fd() helper

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/cgroups/cgroup_utils.c b/src/lxc/cgroups/cgroup_utils.c
index dc7813441efa83b6e624897121264bfb5079f35b..1ffc63fa9c0e5d5da975d367ea0541db10db3c47 100644 (file)
--- a/src/lxc/cgroups/cgroup_utils.c
+++ b/src/lxc/cgroups/cgroup_utils.c
@@ -98,3 +98,16 @@ int unified_cgroup_hierarchy(void)
 
        return 0;
 }
+
+int unified_cgroup_fd(int fd)
+{
+
+       int ret;
+       struct statfs fs;
+
+       ret = fstatfs(fd, &fs);
+       if (!ret && is_fs_type(&fs, CGROUP2_SUPER_MAGIC))
+               return true;
+
+       return false;
+}

diff --git a/src/lxc/cgroups/cgroup_utils.h b/src/lxc/cgroups/cgroup_utils.h
index 17d7b2ffee0fcec240db5b4d48e33697779043b7..818eead1de42453fa757f9da303e08e2e4f9866f 100644 (file)
--- a/src/lxc/cgroups/cgroup_utils.h
+++ b/src/lxc/cgroups/cgroup_utils.h
@@ -30,4 +30,6 @@ __hidden extern bool test_writeable_v2(char *mountpoint, char *path);
 
 __hidden extern int unified_cgroup_hierarchy(void);
 
+__hidden extern int unified_cgroup_fd(int fd);
+
 #endif /* __LXC_CGROUP_UTILS_H */