fix: dbus signal monitor not returning due to old tail version

Apparently older versions of tail work differently, causing them to never finish

Using process substitution we avoid both the temp file and tail alltogether

refs: #490

Author: luisbocanegra

package/contents/ui/DBusSignalMonitor.qml

@@ -50,8 +50,7 @@ Item {
 
     function start() {
         runCommand.exec(root.monitorCmd, o => {
-            // exit code 130 indicates received signal from the script
-            if (o.exitCode === 130) {
+            if (o.exitCode === 0) {
                 root.signalReceived(root.getMessage(o.stdout.trim()));
                 // restart for the next signal
                 // for some reason it won't restart without a delay???

package/contents/ui/tools/gdbus_get_signal.sh

@@ -7,21 +7,15 @@ SERVICE=${2}
 INTERFACE=${3}
 DBUS_PATH=${4}
 METHOD=${5}
-TMPFILE=$(mktemp)
-gdbus monitor --"${BUS_TYPE}" --dest "${SERVICE}" >"$TMPFILE" &
-PID=$!
-exit_code=130
-tail -f "$TMPFILE" | while IFS= read -r line; do
+
+while IFS= read -r line; do
   if [[ "$line" == *"${INTERFACE}.${METHOD}"* ]] && [[ "$line" == *"${DBUS_PATH}"* ]]; then
     echo "$line"
-    kill "$PID"
-    break
+    exit 0
   fi
   if [[ "$line" == *"Error"* ]]; then
-    ((exit_code = 1))
-    kill "$PID"
-    break
+    exit 1
   fi
-done
-rm -f "$TMPFILE"
-exit "$exit_code"
+done < <(gdbus monitor --"${BUS_TYPE}" --dest "${SERVICE}")
+
+exit 1