title: DBus SystemBus policies
body: <p>I wrote a program that runs as session service through dbus.<br />
  I wanted to make it run as system service (creating a dbus.SystemBus bus name) if executed by root (uid 0).<br />
  I am trying to run for dbus.SystemBus what I currently run for dbus.SessionBus but get a policy error.<br />
  The code (python but it doesn't really matter), cleared from everything unnecessary, I run is this:</p>
  
  <pre><code>import gobject
  import dbus
  import dbus.service
  from dbus.mainloop.glib import DBusGMainLoop
  
  DBusGMainLoop(set_as_default=True)
  loop = gobject.MainLoop()
  
  class dbusService(dbus.service.Object):
      def __init__(self):
          bus_name = dbus.service.BusName('org.testobj.service', bus=dbus.SystemBus())
          dbus.service.Object.__init__(self, bus_name, '/org/testobj/service')
  
  a = dbusService()
  </code></pre>
  
  <p>and get:</p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "&lt;stdin&gt;", line 3, in __init__
    File "/usr/lib/python2.7/site-packages/dbus/service.py", line 131, in __new__ retval = bus.request_name(name, name_flags)
    File "/usr/lib/python2.7/site-packages/dbus/bus.py", line 303, in request_name 'su', (name, flags))
    File "/usr/lib/python2.7/site-packages/dbus/connection.py", line 651, in call_blocking message, timeout)
  dbus.exceptions.DBusException: org.freedesktop.DBus.Error.AccessDenied: Connection ":1.48" is not allowed to own the service "org.testobj.service" due to security policies in the configuration file
  </code></pre>