update-ids-ruleset: Early exit script if lockfile exists.

This prevents from running the script while the WUI is performing
operations at the same time or to launch multiple instances of the
script.

Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>

src/scripts/update-ids-ruleset

@@ -42,6 +42,17 @@ if ( $> == 0 ) {
 	POSIX::setuid( $uid );
 }
 
+# Check if the IDS lock file exists.
+# In this case the WUI or another instance currently is altering the
+# ruleset.
+if (-f "$IDS::ids_page_lock_file") {
+	# Store notice to the syslog.
+	&IDS::_log_to_syslog("Another process currently is altering the IDS ruleset.");
+
+	# Exit.
+	exit 0;
+}
+
 # Check if the red device is active.
 unless (-e "${General::swroot}/red/active") {
 	# Store notice in the syslog.