implemented sxmo_networkmonitor to monitor when the network goes up/down and execute hooks

This implement a dbus monitor for networkamanger and is useful to
start/stop/restart certain things in user-defined hooks when
connectivity is gained/lost. By default all
it does is ensure the status bar is updated quickly to reflect the
network status.

Signed-off-by: Maarten van Gompel <proycon@anaproy.nl>

scripts/core/sxmo_networkmonitor.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env sh
+
+# include common definitions
+# shellcheck source=scripts/core/sxmo_common.sh
+. "$(dirname "$0")/sxmo_common.sh"
+
+gracefulexit() {
+	sxmo_statusbarupdate.sh
+	sleep 1
+	echo "sxmo_networkmonitor: gracefully exiting (on signal or after error)">&2
+	kill -9 0
+}
+
+trap "gracefulexit" INT TERM
+
+dbus-monitor --system "interface='org.freedesktop.NetworkManager',type='signal',member='StateChanged'" | \
+	while read -r line; do
+		if echo "$line" | grep -E "^signal.*StateChanged"; then
+			# shellcheck disable=SC2034
+			read -r newstate
+			if echo "$newstate" | grep "int32 70"; then
+				#network just connected (70=NM_STATE_CONNECTED_GLOBAL)
+				echo "network up">&2
+				if [ -x "$XDG_CONFIG_HOME/sxmo/hooks/network-up" ]; then
+					"$XDG_CONFIG_HOME/sxmo/hooks/network-up" &
+				fi
+				sxmo_statusbarupdate.sh
+			elif echo "$newstate" | grep "int32 20"; then
+				#network just disconnected (20=NM_STATE_DISCONNECTED)
+				echo "network down">&2
+				if [ -x "$XDG_CONFIG_HOME/sxmo/hooks/network-down" ]; then
+					"$XDG_CONFIG_HOME/sxmo/hooks/network-down" &
+				fi
+				sxmo_statusbarupdate.sh
+			elif echo "$newstate" | grep "int32 30"; then
+				#network is going down (30=NM_STATE_DISCONNECTING)
+				if [ -x "$XDG_CONFIG_HOME/sxmo/hooks/network-pre-down" ]; then
+					"$XDG_CONFIG_HOME/sxmo/hooks/network-pre-down" &
+				fi
+			fi
+		fi
+	done &
+
+wait

scripts/core/sxmo_xinit.sh

@@ -69,6 +69,7 @@ daemons() {
 daemonsneedingdbus() {
 	dunst -conf /usr/share/sxmo/appcfg/dunst.conf &
 	sxmo_notificationmonitor.sh &
+	sxmo_networkmonitor.sh &
 	sxmo_lisgdstart.sh &
 }