Don't fail on DBus connection error or opening log

Especially in offline mode - like during installation, tests etc.

QubesOS/qubes-issues#2412

qubes/ext/qubesmanager.py

@@ -36,12 +36,19 @@ import qubes.ext
 class QubesManager(qubes.ext.Extension):
     def __init__(self, *args, **kwargs):
         super(QubesManager, self).__init__(*args, **kwargs)
-        self._system_bus = dbus.SystemBus()
+        try:
+            self._system_bus = dbus.SystemBus()
+        except dbus.exceptions.DBusException:
+            # we can't access Qubes() object here to check for offline mode,
+            # so lets assume it is this case...
+            self._system_bus = None
 
     # pylint: disable=no-self-use,unused-argument,too-few-public-methods
 
     @qubes.ext.handler('status:error')
     def on_status_error(self, vm, event, status, message):
+        if self._system_bus is None:
+            return
         try:
             qubes_manager = self._system_bus.get_object(
                 'org.qubesos.QubesManager',
@@ -54,6 +61,8 @@ class QubesManager(qubes.ext.Extension):
 
     @qubes.ext.handler('status:no-error')
     def on_status_no_error(self, vm, event, status, message):
+        if self._system_bus is None:
+            return
         try:
             qubes_manager = self._system_bus.get_object(
                 'org.qubesos.QubesManager',

qubes/log.py

@@ -99,7 +99,16 @@ def enable():
     handler_console.setFormatter(formatter_console)
     logging.root.addHandler(handler_console)
 
-    handler_log = logging.FileHandler('log', 'a', encoding='utf-8')
+    if os.path.exists('/var/log/qubes'):
+        log_path = '/var/log/qubes/qubes.log'
+    else:
+        # for tests, travis etc
+        log_path = '/tmp/qubes.log'
+    old_umask = os.umask(0o007)
+    try:
+        handler_log = logging.FileHandler(log_path, 'a', encoding='utf-8')
+    finally:
+        os.umask(old_umask)
     handler_log.setFormatter(formatter_log)
     logging.root.addHandler(handler_log)