fff-layer3-config: Disable SIGHUP during test mode

The SIGHUP signal is sent to a process if a hangup is detected on the
controlling terminal. This might happen if the ssh session, from which
the test mode was started, is disconnected.

Because ssh session disconnects might happen due to network
reconfiguration, aborting the test mode without restoring the old
settings might make the device unreachable.

Instead, disable the SIGHUP signal when test mode is activated, so
the script is either killed by the user (after successful configuration)
or the timer expires and the old settings are restored.

Fixes: #141

Signed-off-by: Fabian Bläse <fabian@blaese.de>
Reviewed-by: Christian Dresel <freifunk@dresel.systems>
Reviewed-by: Johannes Kimmel <fff@bareminimum.eu>

src/packages/fff/fff-layer3-config/Makefile

@@ -1,7 +1,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=fff-layer3-config
-PKG_RELEASE:=7
+PKG_RELEASE:=8
 
 include $(INCLUDE_DIR)/package.mk
 

src/packages/fff/fff-layer3-config/files/usr/sbin/configure-layer3

@@ -73,6 +73,7 @@ keep_changes() {
 test_changes() {
 	echo $$ > /tmp/configure-layer3-pid
 	trap keep_changes SIGINT SIGTERM
+	trap : SIGHUP
 
 	reload_services