app: script: Improve handling to trace stop

CMUX Modem traces should be stopped before any attempt to close the
CMUX pipes. Otherwise it might hang up the ldattach utility.

Signed-off-by: Seppo Takalo <seppo.takalo@nordicsemi.no>

Author: SeppoTakalo

app/scripts/sm_start_ppp.sh

@@ -230,18 +230,22 @@ fi
 sleep 3
 
 stty -F $AT_CMUX clocal
+test -c $AT_CMUX
 
+if [ $TRACE -gt 0 ]; then
+	echo "Starting trace collection..."
+	start-stop-daemon --start --pidfile $TRACE_PID_FILE --make-pidfile \
+	 --background --exec /bin/dd -- if=$MT_CMUX of=$MODEM_TRACE_FILE bs=1024
+fi
 echo "Connect and wait for PPP link..."
-test -c $AT_CMUX
-test $TRACE -gt 0 && start-stop-daemon --start --pidfile $TRACE_PID_FILE --make-pidfile --background --exec /bin/dd -- if=$MT_CMUX of=$MODEM_TRACE_FILE bs=1024
 
 chat $CHATOPT -t$TIMEOUT "${CHAT_SCRIPT[@]}" >$AT_CMUX <$AT_CMUX
 
 shutdown_modem() {
 	set +eu
+	start-stop-daemon --stop --pidfile $TRACE_PID_FILE --remove-pidfile --oknodo --retry 1
 	chat $CHATOPT -t5 '' $SHUTDOWN_SCRIPT >$AT_CMUX <$AT_CMUX
 	CHAT_ERR=$?
-	start-stop-daemon --stop --pidfile $TRACE_PID_FILE --remove-pidfile --oknodo
 	pkill ldattach
 	sleep 1
 	if [ "$CHAT_ERR" -ne 0 ]; then

app/scripts/sm_stop_ppp.sh

@@ -8,17 +8,16 @@ PIDFILE="/var/run/nrf91-modem.pid"
 PPP_PIDFILE="/var/run/ppp-nrf91.pid"
 TRACE_PID_FILE="/var/run/nrf91-modem-trace.pid"
 
-# Request PPPD to terminate
-if [ -f $PPP_PIDFILE ]; then
-        echo "Stopping PPP link..."
-        kill -SIGTERM $(head -1 <$PPP_PIDFILE)
-fi
-
 # Stop trace collection
 if [ -f $TRACE_PID_FILE ]; then
         echo "Stopping trace collection..."
-        kill $(cat $TRACE_PID_FILE) 2>/dev/null || true
-        rm -f $TRACE_PID_FILE
+        start-stop-daemon --stop --pidfile $TRACE_PID_FILE --remove-pidfile --oknodo --retry 1
+fi
+
+# Request PPPD to terminate
+if [ -f $PPP_PIDFILE ]; then
+        echo "Stopping PPP link..."
+        start-stop-daemon --stop --pidfile $PPP_PIDFILE
 fi
 
 # Wait for Shutdown script to complete