cgroups: move cgns_supported() to cgroup utilities

src/lxc/attach.c

@@ -27,7 +27,8 @@
 #include "af_unix.h"
 #include "attach.h"
 #include "caps.h"
-#include "cgroup.h"
+#include "cgroups/cgroup.h"
+#include "cgroups/cgroup_utils.h"
 #include "commands.h"
 #include "conf.h"
 #include "config.h"

src/lxc/cgroups/cgroup_utils.h

@@ -7,6 +7,7 @@
 #include <stdio.h>
 
 #include "compiler.h"
+#include "file_utils.h"
 
 /* Retrieve the cgroup version of a given entry from /proc/<pid>/mountinfo. */
 __hidden extern int get_cgroup_version(char *line);
@@ -32,4 +33,14 @@ __hidden extern int unified_cgroup_hierarchy(void);
 
 __hidden extern int unified_cgroup_fd(int fd);
 
+static inline bool cgns_supported(void)
+{
+	static int supported = -1;
+
+	if (supported == -1)
+		supported = file_exists("/proc/self/ns/cgroup");
+
+	return supported == 1;
+}
+
 #endif /* __LXC_CGROUP_UTILS_H */

src/lxc/lsm/apparmor.c

@@ -13,6 +13,7 @@
 #include <unistd.h>
 
 #include "caps.h"
+#include "cgroups/cgroup_utils.h"
 #include "conf.h"
 #include "config.h"
 #include "initutils.h"

src/lxc/start.c

@@ -27,7 +27,8 @@
 
 #include "af_unix.h"
 #include "caps.h"
-#include "cgroup.h"
+#include "cgroups/cgroup.h"
+#include "cgroups/cgroup_utils.h"
 #include "commands.h"
 #include "commands_utils.h"
 #include "compiler.h"

src/lxc/utils.c

@@ -747,11 +747,6 @@ char *on_path(const char *cmd, const char *rootfs)
 	return NULL;
 }
 
-bool cgns_supported(void)
-{
-	return file_exists("/proc/self/ns/cgroup");
-}
-
 /* historically lxc-init has been under /usr/lib/lxc and under
  * /usr/lib/$ARCH/lxc.  It now lives as $prefix/sbin/init.lxc.
  */

src/lxc/utils.h

@@ -138,7 +138,6 @@ __hidden extern bool is_shared_mountpoint(const char *path);
 __hidden extern int detect_shared_rootfs(void);
 __hidden extern bool detect_ramfs_rootfs(void);
 __hidden extern char *on_path(const char *cmd, const char *rootfs);
-__hidden extern bool cgns_supported(void);
 __hidden extern char *choose_init(const char *rootfs);
 __hidden extern bool switch_to_ns(pid_t pid, const char *ns);
 __hidden extern char *get_template_path(const char *t);

src/tests/lxc_raw_clone.c

@@ -37,6 +37,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
+#include "cgroups/cgroup_utils.h"
 #include "lxctest.h"
 #include "namespace.h"
 #include "process_utils.h"