Accurately detect whether a system supports clone_children

If multiple cgroups are mounted under /sys/fs/cgroup, then the
original check ends up looking for /sys/fs/cgroup/cgroup.clone_children,
which does not exist because that is just a tmpfs.

So make sure to check an actual cgroupfs.

Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

diff --git a/src/lxc/lxc-checkconfig.in b/src/lxc/lxc-checkconfig.in
index 5dcf3a44b87c2608b77fddec812ff8c64fd2c8e9..30f618601118f5de503a8a59d40d7f33e26d221c 100755 (executable)
--- a/src/lxc/lxc-checkconfig.in
+++ b/src/lxc/lxc-checkconfig.in
@@ -63,7 +63,12 @@ echo -n "Multiple /dev/pts instances: " && is_enabled DEVPTS_MULTIPLE_INSTANCES
 echo
 echo "--- Control groups ---"
 
-CGROUP_MNT_PATH=$(grep -m1 "^cgroup" /proc/self/mounts | awk '{ print $2 }')
+print_cgroups() {
+  # print all mountpoints for cgroup filesystems
+  awk '$1 !~ /#/ && $3 == mp { print $2; } ; END { exit(0); } '  "mp=$1" "$2" ;
+}
+
+CGROUP_MNT_PATH=`print_cgroups cgroup /proc/self/mounts | head -1`
 
 echo -n "Cgroup: " && is_enabled CONFIG_CGROUPS yes