lxc-netstat: improve finding fs mountpoint of hierarchy

We cannot assume that the mount source name always starts with 'cgroup'
so we check the filesystem type instead.

Use 'awk' instead of 'grep -E' and  as it is a better tool for this job.

This fixes the tool on systems using openrc.

Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

diff --git a/src/lxc/lxc-netstat.in b/src/lxc/lxc-netstat.in
index 87bd3ebb5460c88cd6b748525fa137cb64617cb9..6d08ce3797a51cb9997b886a965673ed941cb4a5 100644 (file)
--- a/src/lxc/lxc-netstat.in
+++ b/src/lxc/lxc-netstat.in
@@ -51,7 +51,8 @@ get_parent_cgroup()
         init_cgroup=${fields#*:}
 
         # Get the filesystem mountpoint of the hierarchy
-        mountpoint=$(grep -E "^cgroup [^ ]+ [^ ]+ ([^ ]+,)?$subsystems(,[^ ]+)? " /proc/self/mounts | cut -d ' ' -f 2)
+        mountpoint=$(awk -v subsysregex="(^|,)$subsystems(,|\$)" \
+            '$3 == "cgroup" && $4 ~ subsysregex {print $2}' /proc/self/mounts)
         if [ -z "$mountpoint" ]; then continue; fi
 
         # Return the absolute path to the containers' parent cgroup