solaar: clean up gtk code

lib/solaar/gtk.py

@@ -21,6 +21,8 @@
 import importlib
 import logging
 import os.path
+import signal
+import sys
 import tempfile
 
 from logging import INFO as _INFO
@@ -44,7 +46,6 @@ def _require(module, os_package, gi=None, gi_package=None, gi_version=None):
             gi.require_version(gi_package, gi_version)
         return importlib.import_module(module)
     except (ImportError, ValueError):
-        import sys
         sys.exit('%s: missing required system package %s' % (NAME, os_package))
 
 
@@ -122,27 +123,22 @@ def _parse_arguments():
 
 
 # On first SIGINT, dump threads to stderr; on second, exit
-def _handlesigint(signal, stack):
+def _handlesig(signl, stack):
     import faulthandler
-    import signal
-    import sys
-
     signal.signal(signal.SIGINT, signal.SIG_DFL)
+    signal.signal(signal.SIGTERM, signal.SIG_DFL)
 
-    if _log.isEnabledFor(_INFO):
-        faulthandler.dump_traceback()
-
-    sys.exit('%s: exit due to keyboard interrupt' % (NAME.lower()))
+    if signl == int(signal.SIGINT):
+        if _log.isEnabledFor(_INFO):
+            faulthandler.dump_traceback()
+        sys.exit('%s: exit due to keyboard interrupt' % (NAME.lower()))
+    else:
+        sys.exit('')
 
 
 def main():
     _require('pyudev', 'python3-pyudev')
 
-    # handle ^C in console
-    import signal
-    signal.signal(signal.SIGINT, signal.SIG_DFL)
-    signal.signal(signal.SIGINT, _handlesigint)
-
     args = _parse_arguments()
     if not args:
         return
@@ -153,6 +149,11 @@ def main():
     gi = _require('gi', 'python3-gi (in Ubuntu) or python3-gobject (in Fedora)')
     _require('gi.repository.Gtk', 'gir1.2-gtk-3.0', gi, 'Gtk', '3.0')
 
+    # handle ^C in console
+    signal.signal(signal.SIGINT, signal.SIG_DFL)
+    signal.signal(signal.SIGINT, _handlesig)
+    signal.signal(signal.SIGTERM, _handlesig)
+
     udev_file = '42-logitech-unify-permissions.rules'
     if _log.isEnabledFor(_WARNING) \
        and not os.path.isfile('/etc/udev/rules.d/' + udev_file) \
@@ -178,8 +179,6 @@ def main():
         # main UI event loop
         ui.run_loop(listener.start_all, listener.stop_all, args.window != 'only', args.window != 'hide')
     except Exception:
-        import sys
-
         from traceback import format_exc
         sys.exit('%s: error: %s' % (NAME.lower(), format_exc()))