network-hotplug-bridges: Fix warning when address doesn't exist

Some devices do not have an address, which prints an error when reading
it.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

diff --git a/config/udev/network-hotplug-bridges b/config/udev/network-hotplug-bridges
index bacf722ef96d62523ea0b5d2963e103c9d705c68..4b8764598d1d55e6339cf52836483b1f1b1fccb1 100644 (file)
--- a/config/udev/network-hotplug-bridges
+++ b/config/udev/network-hotplug-bridges
@@ -41,9 +41,8 @@ detect_zone() {
                # Try to find out if this INTERFACE is a slave of a zone
                local slave
                for slave in $(get_value "${zone}_SLAVES"); do
-
-                       #Compare if the mac address matches or if the name matches
-                       if ([ "$(</sys/class/net/${INTERFACE}/address)" = "${slave}" ] || [ "${INTERFACE}" = "${slave}" ]); then
+                       # Compare if the mac address matches or if the name matches
+                       if [ -r "/sys/class/net/${INTERFACE}/address" -a "$(</sys/class/net/${INTERFACE}/address)" = "${slave}" ] || [ "${INTERFACE}" = "${slave}" ]; then
                                echo "${zone}"
                                return 0
                        fi