Index: xfce4-session/xfsm-shutdown-helper-sudo.c
===================================================================
--- xfce4-session/xfsm-shutdown-helper-sudo.c	(revision 22728)
+++ xfce4-session/xfsm-shutdown-helper-sudo.c	(working copy)
@@ -1,6 +1,6 @@
 /* $Id$ */
 /*-
- * Copyright (c) 2003-2004 Benedikt Meurer <benny@xfce.org>
+ * Copyright (c) 2003-2006 Benedikt Meurer <benny@xfce.org>
  * All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
@@ -53,6 +53,10 @@
 #include <unistd.h>
 #endif
 
+#ifdef HAVE_DBUS
+#include <dbus/dbus.h>
+#endif
+
 #include <libxfce4util/libxfce4util.h>
 
 #include <xfce4-session/xfsm-shutdown-helper.h>
@@ -65,9 +69,87 @@
   FILE    *infile;
   FILE    *outfile;
   gboolean need_password;
+#ifdef HAVE_DBUS
+  gboolean using_hal;
+#endif
 };
 
 
+#ifdef HAVE_DBUS
+static gboolean
+hal_ping (void)
+{
+  DBusConnection *connection;
+  DBusMessage    *message;
+  DBusMessage    *result;
+  DBusError       derror;
+
+  dbus_error_init (&derror);
+
+  /* connect to the system bus */
+  connection = dbus_bus_get (DBUS_BUS_SYSTEM, &derror);
+  if (G_UNLIKELY (connection == NULL))
+    return FALSE;
+
+  /* ping HAL */
+  message = dbus_message_new_method_call ("org.freedesktop.Hal",
+                                          "/org/freedesktop/Hal/devices/computer",
+                                          "org.freedesktop.DBus.Peer",
+                                          "Ping");
+  result = dbus_connection_send_with_reply_and_block (connection, message, 2000, &derror);
+  dbus_message_unref (message);
+
+  /* check if HAL is available */
+  if (result == NULL)
+    {
+      dbus_error_free (&derror);
+      return FALSE;
+    }
+
+  /* HAL is available */
+  dbus_message_unref (result);
+  return TRUE;
+}
+
+
+static gboolean
+hal_send_command (const gchar *method_name)
+{
+  DBusConnection *connection;
+  DBusMessage    *message;
+  DBusMessage    *result;
+  DBusError       derror;
+
+  dbus_error_init (&derror);
+
+  /* connect to the system bus */
+  connection = dbus_bus_get (DBUS_BUS_SYSTEM, &derror);
+  if (G_UNLIKELY (connection == NULL))
+    return FALSE;
+
+  /* send the command to HAL */
+  message = dbus_message_new_method_call ("org.freedesktop.Hal",
+                                          "/org/freedesktop/Hal/devices/computer",
+                                          "org.freedesktop.Hal.Device.SystemPowerManagement",
+                                          method_name);
+  result = dbus_connection_send_with_reply_and_block (connection, message, 2000, &derror);
+  dbus_message_unref (message);
+
+  /* check if the command succeed */
+  if (result == NULL)
+    {
+      g_warning ("Failed to send command \"%s\" to HAL: %s", method_name, derror.message);
+      dbus_error_free (&derror);
+      return FALSE;
+    }
+
+  /* the command succeed */
+  dbus_message_unref (result);
+  return TRUE;
+}
+#endif
+
+
 XfsmShutdownHelper*
 xfsm_shutdown_helper_spawn (void)
 {
@@ -80,6 +162,21 @@
   int                 result;
   int                 n;
 
+#ifdef HAVE_DBUS
+  /* check if we can use HAL first */
+  if (hal_ping ())
+    {
+      helper = g_new0 (XfsmShutdownHelper, 1);
+      helper->using_hal = TRUE;
+      return helper;
+    }
+  else
+    {
+      g_warning ("HAL is not available, falling back to sudo "
+                 "to shutdown the system from within Xfce.");
+    }
+#endif
+
   sudo = g_find_program_in_path ("sudo");
   if (G_UNLIKELY (sudo == NULL))
     {
@@ -279,6 +376,18 @@
   g_return_val_if_fail (helper != NULL, FALSE);
   g_return_val_if_fail (!helper->need_password, FALSE);
 
+#ifdef HAVE_DBUS
+  /* check if we're using HAL */
+  if (helper->using_hal)
+    {
+      /* send the command to HAL */
+      if (command == XFSM_SHUTDOWN_REBOOT)
+        return hal_send_command ("Reboot");
+      else
+        return hal_send_command ("Shutdown");
+    }
+#endif
+
   fprintf (helper->outfile, "%s\n", command_table[command]);
   fflush (helper->outfile);
 
Index: xfce4-session/Makefile.am
===================================================================
--- xfce4-session/Makefile.am	(revision 22728)
+++ xfce4-session/Makefile.am	(working copy)
@@ -1,5 +1,6 @@
 INCLUDES =								\
-	-I$(top_srcdir)
+	-I$(top_srcdir)							\
+	-DDBUS_API_SUBJECT_TO_CHANGE
 
 man_MANS = xfce4-session.1
 
@@ -42,6 +43,7 @@
 	xfsm-startup.h
 
 xfce4_session_CFLAGS =							\
+	@DBUS_CFLAGS@							\
 	@GNOME_CFLAGS@							\
 	@LIBSM_CFLAGS@							\
 	@LIBX11_CFLAGS@							\
@@ -60,6 +62,7 @@
 	@LIBX11_LIBS@							\
 	@LIBXFCE4MCS_CLIENT_LIBS@					\
 	@LIBXFCEGUI4_LIBS@						\
+	@DBUS_LIBS@							\
 	@GNOME_LIBS@
 
 xfce4_session_DEPENDENCIES =						\
Index: configure.in.in
===================================================================
--- configure.in.in	(revision 22728)
+++ configure.in.in	(working copy)
@@ -36,7 +36,7 @@
 AC_MINIX()
 AM_CONDITIONAL([HAVE_OS_CYGWIN], [test x"`uname | grep \"CYGWIN\"`" != x""])
 if test x"`uname | grep \"CYGWIN\"`" != x""; then
-	AC_DEFINE([HAVE_OS_CYGWIN], [1], [Compiling under cygwin])
+  AC_DEFINE([HAVE_OS_CYGWIN], [1], [Compiling under cygwin])
 fi
 
 dnl check for basic programs
@@ -75,6 +75,10 @@
 dnl Configure the MCS plugins
 XDT_XFCE_MCS_PLUGIN([XFCE_MCS_MANAGER], [4.3.90.2])
 
+dnl Check for DBUS support
+XDT_CHECK_OPTIONAL_PACKAGE([DBUS], [dbus-1], [0.34], [dbus],
+                           [D-Bus support (for HAL)], [yes])
+
 dnl Check for gnome support
 XDT_CHECK_OPTIONAL_PACKAGE([GNOME], [libgnome-2.0], [2.4.0], [gnome],
                            [Assistive technologies support], [no])