Merge ~morphis/snappy-hwe-snaps/+git/wifi-ap:check-interface-is-available into ~snappy-hwe-team/snappy-hwe-snaps/+git/wifi-ap:master

[Simon Fels]

Before we start using a WiFi network interface check if it is present and fail if that is not the case.

[Konrad Zapałowicz (kzapalowicz)]

Ack

review: Approve

[Matteo Croce (teknoraver)]

review: Approve

diff --git a/bin/ap.sh b/bin/ap.sh
index 66aa782..f017554 100755
--- a/bin/ap.sh
+++ b/bin/ap.sh
@@ -26,11 +26,18 @@ fi
 
 DEFAULT_ACCESS_POINT_INTERFACE="ap0"
 
-if [ "$DISABLED" == "1" ] ; then
+if [ $DISABLED -eq 1 ] ; then
 	echo "Not starting as WiFi AP is disabled"
 	exit 0
 fi
 
+# Make sure the configured WiFi interface is really available before
+# doing anything.
+if ! ifconfig $WIFI_INTERFACE ; then
+	echo "ERROR: WiFi interface $WIFI_INTERFACE is not available!"
+	exit 1
+fi
+
 shutdown() {
 	DNSMASQ_PID=$(cat $SNAP_DATA/dnsmasq.pid)
 	kill -TERM $DNSMASQ_PID