tools/dbus-launch-x11.c - platform/external/dbus - Git at Google

 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
 /* dbus-launch.h  dbus-launch utility
  *
  * Copyright (C) 2006 Thiago Macieira <[email protected]>
  *
  * Licensed under the Academic Free License version 2.1
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  *
  */

 #include <config.h>
 #include "dbus-launch.h"

 #ifdef DBUS_BUILD_X11
 #include <stdlib.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
 #include <pwd.h>
 #include <X11/Xlib.h>
 #include <X11/Xatom.h>

 Display *xdisplay = NULL;
 static Atom selection_atom;
 static Atom address_atom;
 static Atom pid_atom;

 static int
 x_io_error_handler (Display *xdisplay)
 {
   verbose ("X IO error\n");
   kill_bus_and_exit (0);
   return 0;
 }

 static void
 remove_prefix (char *s,
                char *prefix)
 {
   int plen;

   plen = strlen (prefix);

   if (strncmp (s, prefix, plen) == 0)
     {
       memmove (s, s + plen, strlen (s) - plen + 1);
     }
 }

 static const char*
 get_homedir (void)
 {
   const char *home;

   home = getenv ("HOME");
   if (home == NULL)
     {
       /* try from the user database */
       struct passwd *user = getpwuid (getuid());
       if (user != NULL)
         home = user->pw_dir;
     }

   if (home == NULL)
     {
       fprintf (stderr, "Can't get user home directory\n");
       exit (1);
     }

   return home;
 }

 #define DBUS_DIR ".dbus"
 #define DBUS_SESSION_BUS_DIR "session-bus"

 static char *
 get_session_file (void)
 {
   static const char prefix[] = "/" DBUS_DIR "/" DBUS_SESSION_BUS_DIR "/";
   const char *machine;
   const char *home;
   char *display;
   char *result;
   char *p;

   machine = get_machine_uuid ();
   if (machine == NULL)
     return NULL;

   display = xstrdup (getenv ("DISPLAY"));
   if (display == NULL)
     {
       verbose ("X11 integration disabled because X11 is not running\n");
       return NULL;
     }

   /* remove the screen part of the display name */
   p = strrchr (display, ':');
   if (p != NULL)
     {
       for ( ; *p; ++p)
         {
           if (*p == '.')
             {
               *p = '\0';
               break;
             }
         }
     }

   /* Note that we leave the hostname in the display most of the
    * time. The idea is that we want to be per-(machine,display,user)
    * triplet to be extra-sure we get a bus we can connect to. Ideally
    * we'd recognize when the hostname matches the machine we're on in
    * all cases; we do try to drop localhost and localhost.localdomain
    * as a special common case so that alternate spellings of DISPLAY
    * don't result in extra bus instances.
    *
    * We also kill the ":" if there's nothing in front of it. This
    * avoids an ugly double underscore in the filename.
    */
   remove_prefix (display, "localhost.localdomain:");
   remove_prefix (display, "localhost:");
   remove_prefix (display, ":");

   /* replace the : in the display with _ if the : is still there.
    * use _ instead of - since it can't be in hostnames.
    */
   for (p = display; *p; ++p)
     {
       if (*p == ':')
         *p = '_';
     }

   home = get_homedir ();

   result = malloc (strlen (home) + strlen (prefix) + strlen (machine) +
                    strlen (display) + 2);
   if (result == NULL)
     {
       /* out of memory */
       free (display);
       return NULL;
     }

   strcpy (result, home);
   strcat (result, prefix);
   strcat (result, machine);
   strcat (result, "-");
   strcat (result, display);
   free (display);

   verbose ("session file: %s\n", result);
   return result;
 }

 static void
 ensure_session_directory (void)
 {
   const char *home;
   char *dir;

   home = get_homedir ();

   /* be sure we have space for / and nul */
   dir = malloc (strlen (home) + strlen (DBUS_DIR) + strlen (DBUS_SESSION_BUS_DIR) + 3);
   if (dir == NULL)
     {
       fprintf (stderr, "no memory\n");
       exit (1);
     }

   strcpy (dir, home);
   strcat (dir, "/");
   strcat (dir, DBUS_DIR);

   if (mkdir (dir, 0700) < 0)
     {
       /* only print a warning here, writing the session file itself will fail later */
       if (errno != EEXIST)
         fprintf (stderr, "Unable to create %s\n", dir);
     }

   strcat (dir, "/");
   strcat (dir, DBUS_SESSION_BUS_DIR);

   if (mkdir (dir, 0700) < 0)
     {
       /* only print a warning here, writing the session file itself will fail later */
       if (errno != EEXIST)
         fprintf (stderr, "Unable to create %s\n", dir);
     }

   free (dir);
 }

 static Display *
 open_x11 (void)
 {
   if (xdisplay != NULL)
     return xdisplay;

   xdisplay = XOpenDisplay (NULL);
   if (xdisplay != NULL)
     {
       verbose ("Connected to X11 display '%s'\n", DisplayString (xdisplay));
       XSetIOErrorHandler (x_io_error_handler);
     }
   return xdisplay;
 }

 static int
 init_x_atoms (Display *display)
 {
   static const char selection_prefix[] = "_DBUS_SESSION_BUS_SELECTION_";
   static const char address_prefix[] = "_DBUS_SESSION_BUS_ADDRESS";
   static const char pid_prefix[] = "_DBUS_SESSION_BUS_PID";
   static int init = FALSE;
   char *atom_name;
   const char *machine;
   char *user_name;
   struct passwd *user;

   if (init)
     return TRUE;

   machine = get_machine_uuid ();
   if (machine == NULL)
     return FALSE;

   user = getpwuid (getuid ());
   if (user == NULL)
     {
       verbose ("Could not determine user information; aborting X11 integration.\n");
       return FALSE;
     }
   user_name = xstrdup(user->pw_name);

   atom_name = malloc (strlen (machine) + strlen (user_name) + 2 +
                       MAX (strlen (selection_prefix),
                            MAX (strlen (address_prefix),
                                 strlen (pid_prefix))));
   if (atom_name == NULL)
     {
       verbose ("Could not create X11 atoms; aborting X11 integration.\n");
       free (user_name);
       return FALSE;
     }

   /* create the selection atom */
   strcpy (atom_name, selection_prefix);
   strcat (atom_name, user_name);
   strcat (atom_name, "_");
   strcat (atom_name, machine);
   selection_atom = XInternAtom (display, atom_name, FALSE);

   /* create the address property atom */
   strcpy (atom_name, address_prefix);
   address_atom = XInternAtom (display, atom_name, FALSE);

   /* create the PID property atom */
   strcpy (atom_name, pid_prefix);
   pid_atom = XInternAtom (display, atom_name, FALSE);

   free (atom_name);
   free (user_name);
   init = TRUE;
   return TRUE;
 }

 /*
  * Gets the daemon address from the X11 display.
  * Returns FALSE if there was an error. Returning
  * TRUE does not mean the address exists.
  */
 int
 x11_get_address (char **paddress, pid_t *pid, long *wid)
 {
   int result;
   Atom type;
   Window owner;
   int format;
   unsigned long items;
   unsigned long after;
   char *data;

   *paddress = NULL;

   /* locate the selection owner */
   owner = XGetSelectionOwner (xdisplay, selection_atom);
   if (owner == None)
     return TRUE;                /* no owner */
   if (wid != NULL)
     *wid = (long) owner;

   /* get the bus address */
   result = XGetWindowProperty (xdisplay, owner, address_atom, 0, 1024, False,
                               XA_STRING, &type, &format, &items, &after,
                               (unsigned char **) &data);
   if (result != Success || type == None || after != 0 || data == NULL || format != 8)
     return FALSE;               /* error */

   *paddress = xstrdup (data);
   XFree (data);

   /* get the PID */
   if (pid != NULL)
     {
       *pid = 0;
       result = XGetWindowProperty (xdisplay, owner, pid_atom, 0, sizeof pid, False,
                                    XA_CARDINAL, &type, &format, &items, &after,
                                    (unsigned char **) &data);
       if (result == Success && type != None && after == 0 && data != NULL && format == 32)
         *pid = (pid_t) *(long*) data;
       XFree (data);
     }

   return TRUE;                  /* success */
 }

 /*
  * Saves the address in the X11 display. Returns 0 on success.
  * If an error occurs, returns -1. If the selection already exists,
  * returns 1. (i.e. another daemon is already running)
  */
 static Window
 set_address_in_x11(char *address, pid_t pid)
 {
   char *current_address;
   Window wid = None;
   unsigned long pid32; /* Xlib property functions want _long_ not 32-bit for format "32" */

   /* lock the X11 display to make sure we're doing this atomically */
   XGrabServer (xdisplay);

   if (!x11_get_address (&current_address, NULL, NULL))
     {
       /* error! */
       goto out;
     }

   if (current_address != NULL)
     {
       /* someone saved the address in the meantime */
       free (current_address);
       goto out;
     }

   /* Create our window */
   wid = XCreateWindow (xdisplay, RootWindow (xdisplay, 0), -20, -20, 10, 10,
                        0, CopyFromParent, InputOnly, CopyFromParent,
                        0, NULL);
   verbose ("Created window %d\n", wid);

   /* Save the property in the window */
   XChangeProperty (xdisplay, wid, address_atom, XA_STRING, 8, PropModeReplace,
                    (unsigned char *)address, strlen (address));
   pid32 = pid;
   XChangeProperty (xdisplay, wid, pid_atom, XA_CARDINAL, 32, PropModeReplace,
                    (unsigned char *)&pid32, 1);

   /* Now grab the selection */
   XSetSelectionOwner (xdisplay, selection_atom, wid, CurrentTime);

  out:
   /* Ungrab the server to let other people use it too */
   XUngrabServer (xdisplay);

   /* And make sure that the ungrab gets sent to X11 */
   XFlush (xdisplay);

   return wid;
 }

 /*
  * Saves the session address in session file. Returns TRUE on
  * success, FALSE if an error occurs.
  */
 static int
 set_address_in_file (char *address, pid_t pid, Window wid)
 {
   char *session_file;
   FILE *f;

   ensure_session_directory ();
   session_file = get_session_file();
   if (session_file == NULL)
     return FALSE;

   f = fopen (session_file, "w");
   free (session_file);
   if (f == NULL)
     return FALSE;               /* some kind of error */
   fprintf (f,
            "# This file allows processes on the machine with id %s using \n"
            "# display %s to find the D-Bus session bus with the below address.\n"
            "# If the DBUS_SESSION_BUS_ADDRESS environment variable is set, it will\n"
            "# be used rather than this file.\n"
            "# See \"man dbus-launch\" for more details.\n"
            "DBUS_SESSION_BUS_ADDRESS=%s\n"
            "DBUS_SESSION_BUS_PID=%ld\n"
            "DBUS_SESSION_BUS_WINDOWID=%ld\n",
            get_machine_uuid (),
            getenv ("DISPLAY"),
            address, (long)pid, (long)wid);

   fclose (f);

   return TRUE;
 }

 int
 x11_save_address (char *address, pid_t pid, long *wid)
 {
   Window id = set_address_in_x11 (address, pid);
   if (id != None)
     {
       if (!set_address_in_file (address, pid, id))
         return FALSE;

       if (wid != NULL)
         *wid = (long) id;
       return TRUE;
     }
   return FALSE;
 }

 int
 x11_init (void)
 {
   return open_x11 () != NULL && init_x_atoms (xdisplay);
 }

 void
 x11_handle_event (void)
 {
   if (xdisplay != NULL)
     {
       while (XPending (xdisplay))
         {
           XEvent ignored;
           XNextEvent (xdisplay, &ignored);
         }
     }
 }

 #else
 void dummy_dbus_launch_x11 (void);

 void dummy_dbus_launch_x11 (void) { }
 #endif
	/* -- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -- */
	/* dbus-launch.h dbus-launch utility
	*
	* Copyright (C) 2006 Thiago Macieira <[email protected]>
	*
	* Licensed under the Academic Free License version 2.1
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	*
	*/

	#include <config.h>
	#include "dbus-launch.h"

	#ifdef DBUS_BUILD_X11
	#include <stdlib.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <unistd.h>
	#include <fcntl.h>
	#include <errno.h>
	#include <stdio.h>
	#include <string.h>
	#include <pwd.h>
	#include <X11/Xlib.h>
	#include <X11/Xatom.h>

	Display *xdisplay = NULL;
	static Atom selection_atom;
	static Atom address_atom;
	static Atom pid_atom;

	static int
	x_io_error_handler (Display *xdisplay)
	{
	verbose ("X IO error\n");
	kill_bus_and_exit (0);
	return 0;
	}

	static void
	remove_prefix (char *s,
	char *prefix)
	{
	int plen;

	plen = strlen (prefix);

	if (strncmp (s, prefix, plen) == 0)
	{
	memmove (s, s + plen, strlen (s) - plen + 1);
	}
	}

	static const char*
	get_homedir (void)
	{
	const char *home;

	home = getenv ("HOME");
	if (home == NULL)
	{
	/* try from the user database */
	struct passwd *user = getpwuid (getuid());
	if (user != NULL)
	home = user->pw_dir;
	}

	if (home == NULL)
	{
	fprintf (stderr, "Can't get user home directory\n");
	exit (1);
	}

	return home;
	}

	#define DBUS_DIR ".dbus"
	#define DBUS_SESSION_BUS_DIR "session-bus"

	static char *
	get_session_file (void)
	{
	static const char prefix[] = "/" DBUS_DIR "/" DBUS_SESSION_BUS_DIR "/";
	const char *machine;
	const char *home;
	char *display;
	char *result;
	char *p;

	machine = get_machine_uuid ();
	if (machine == NULL)
	return NULL;

	display = xstrdup (getenv ("DISPLAY"));
	if (display == NULL)
	{
	verbose ("X11 integration disabled because X11 is not running\n");
	return NULL;
	}

	/* remove the screen part of the display name */
	p = strrchr (display, ':');
	if (p != NULL)
	{
	for ( ; *p; ++p)
	{
	if (*p == '.')
	{
	*p = '\0';
	break;
	}
	}
	}

	/* Note that we leave the hostname in the display most of the
	* time. The idea is that we want to be per-(machine,display,user)
	* triplet to be extra-sure we get a bus we can connect to. Ideally
	* we'd recognize when the hostname matches the machine we're on in
	* all cases; we do try to drop localhost and localhost.localdomain
	* as a special common case so that alternate spellings of DISPLAY
	* don't result in extra bus instances.
	*
	* We also kill the ":" if there's nothing in front of it. This
	* avoids an ugly double underscore in the filename.
	*/
	remove_prefix (display, "localhost.localdomain:");
	remove_prefix (display, "localhost:");
	remove_prefix (display, ":");

	/* replace the : in the display with _ if the : is still there.
	* use _ instead of - since it can't be in hostnames.
	*/
	for (p = display; *p; ++p)
	{
	if (*p == ':')
	*p = '_';
	}

	home = get_homedir ();

	result = malloc (strlen (home) + strlen (prefix) + strlen (machine) +
	strlen (display) + 2);
	if (result == NULL)
	{
	/* out of memory */
	free (display);
	return NULL;
	}

	strcpy (result, home);
	strcat (result, prefix);
	strcat (result, machine);
	strcat (result, "-");
	strcat (result, display);
	free (display);

	verbose ("session file: %s\n", result);
	return result;
	}

	static void
	ensure_session_directory (void)
	{
	const char *home;
	char *dir;

	home = get_homedir ();

	/* be sure we have space for / and nul */
	dir = malloc (strlen (home) + strlen (DBUS_DIR) + strlen (DBUS_SESSION_BUS_DIR) + 3);
	if (dir == NULL)
	{
	fprintf (stderr, "no memory\n");
	exit (1);
	}

	strcpy (dir, home);
	strcat (dir, "/");
	strcat (dir, DBUS_DIR);

	if (mkdir (dir, 0700) < 0)
	{
	/* only print a warning here, writing the session file itself will fail later */
	if (errno != EEXIST)
	fprintf (stderr, "Unable to create %s\n", dir);
	}

	strcat (dir, "/");
	strcat (dir, DBUS_SESSION_BUS_DIR);

	if (mkdir (dir, 0700) < 0)
	{
	/* only print a warning here, writing the session file itself will fail later */
	if (errno != EEXIST)
	fprintf (stderr, "Unable to create %s\n", dir);
	}

	free (dir);
	}

	static Display *
	open_x11 (void)
	{
	if (xdisplay != NULL)
	return xdisplay;

	xdisplay = XOpenDisplay (NULL);
	if (xdisplay != NULL)
	{
	verbose ("Connected to X11 display '%s'\n", DisplayString (xdisplay));
	XSetIOErrorHandler (x_io_error_handler);
	}
	return xdisplay;
	}

	static int
	init_x_atoms (Display *display)
	{
	static const char selection_prefix[] = "_DBUS_SESSION_BUS_SELECTION_";
	static const char address_prefix[] = "_DBUS_SESSION_BUS_ADDRESS";
	static const char pid_prefix[] = "_DBUS_SESSION_BUS_PID";
	static int init = FALSE;
	char *atom_name;
	const char *machine;
	char *user_name;
	struct passwd *user;

	if (init)
	return TRUE;

	machine = get_machine_uuid ();
	if (machine == NULL)
	return FALSE;

	user = getpwuid (getuid ());
	if (user == NULL)
	{
	verbose ("Could not determine user information; aborting X11 integration.\n");
	return FALSE;
	}
	user_name = xstrdup(user->pw_name);

	atom_name = malloc (strlen (machine) + strlen (user_name) + 2 +
	MAX (strlen (selection_prefix),
	MAX (strlen (address_prefix),
	strlen (pid_prefix))));
	if (atom_name == NULL)
	{
	verbose ("Could not create X11 atoms; aborting X11 integration.\n");
	free (user_name);
	return FALSE;
	}

	/* create the selection atom */
	strcpy (atom_name, selection_prefix);
	strcat (atom_name, user_name);
	strcat (atom_name, "_");
	strcat (atom_name, machine);
	selection_atom = XInternAtom (display, atom_name, FALSE);

	/* create the address property atom */
	strcpy (atom_name, address_prefix);
	address_atom = XInternAtom (display, atom_name, FALSE);

	/* create the PID property atom */
	strcpy (atom_name, pid_prefix);
	pid_atom = XInternAtom (display, atom_name, FALSE);

	free (atom_name);
	free (user_name);
	init = TRUE;
	return TRUE;
	}

	/*
	* Gets the daemon address from the X11 display.
	* Returns FALSE if there was an error. Returning
	* TRUE does not mean the address exists.
	*/
	int
	x11_get_address (char *paddress, pid_t pid, long *wid)
	{
	int result;
	Atom type;
	Window owner;
	int format;
	unsigned long items;
	unsigned long after;
	char *data;

	*paddress = NULL;

	/* locate the selection owner */
	owner = XGetSelectionOwner (xdisplay, selection_atom);
	if (owner == None)
	return TRUE; /* no owner */
	if (wid != NULL)
	*wid = (long) owner;

	/* get the bus address */
	result = XGetWindowProperty (xdisplay, owner, address_atom, 0, 1024, False,
	XA_STRING, &type, &format, &items, &after,
	(unsigned char **) &data);
	if (result != Success \|\| type == None \|\| after != 0 \|\| data == NULL \|\| format != 8)
	return FALSE; /* error */

	*paddress = xstrdup (data);
	XFree (data);

	/* get the PID */
	if (pid != NULL)
	{
	*pid = 0;
	result = XGetWindowProperty (xdisplay, owner, pid_atom, 0, sizeof pid, False,
	XA_CARDINAL, &type, &format, &items, &after,
	(unsigned char **) &data);
	if (result == Success && type != None && after == 0 && data != NULL && format == 32)
	pid = (pid_t) (long*) data;
	XFree (data);
	}

	return TRUE; /* success */
	}

	/*
	* Saves the address in the X11 display. Returns 0 on success.
	* If an error occurs, returns -1. If the selection already exists,
	* returns 1. (i.e. another daemon is already running)
	*/
	static Window
	set_address_in_x11(char *address, pid_t pid)
	{
	char *current_address;
	Window wid = None;
	unsigned long pid32; /* Xlib property functions want _long_ not 32-bit for format "32" */

	/* lock the X11 display to make sure we're doing this atomically */
	XGrabServer (xdisplay);

	if (!x11_get_address (&current_address, NULL, NULL))
	{
	/* error! */
	goto out;
	}

	if (current_address != NULL)
	{
	/* someone saved the address in the meantime */
	free (current_address);
	goto out;
	}

	/* Create our window */
	wid = XCreateWindow (xdisplay, RootWindow (xdisplay, 0), -20, -20, 10, 10,
	0, CopyFromParent, InputOnly, CopyFromParent,
	0, NULL);
	verbose ("Created window %d\n", wid);

	/* Save the property in the window */
	XChangeProperty (xdisplay, wid, address_atom, XA_STRING, 8, PropModeReplace,
	(unsigned char *)address, strlen (address));
	pid32 = pid;
	XChangeProperty (xdisplay, wid, pid_atom, XA_CARDINAL, 32, PropModeReplace,
	(unsigned char *)&pid32, 1);

	/* Now grab the selection */
	XSetSelectionOwner (xdisplay, selection_atom, wid, CurrentTime);

	out:
	/* Ungrab the server to let other people use it too */
	XUngrabServer (xdisplay);

	/* And make sure that the ungrab gets sent to X11 */
	XFlush (xdisplay);

	return wid;
	}

	/*
	* Saves the session address in session file. Returns TRUE on
	* success, FALSE if an error occurs.
	*/
	static int
	set_address_in_file (char *address, pid_t pid, Window wid)
	{
	char *session_file;
	FILE *f;

	ensure_session_directory ();
	session_file = get_session_file();
	if (session_file == NULL)
	return FALSE;

	f = fopen (session_file, "w");
	free (session_file);
	if (f == NULL)
	return FALSE; /* some kind of error */
	fprintf (f,
	"# This file allows processes on the machine with id %s using \n"
	"# display %s to find the D-Bus session bus with the below address.\n"
	"# If the DBUS_SESSION_BUS_ADDRESS environment variable is set, it will\n"
	"# be used rather than this file.\n"
	"# See \"man dbus-launch\" for more details.\n"
	"DBUS_SESSION_BUS_ADDRESS=%s\n"
	"DBUS_SESSION_BUS_PID=%ld\n"
	"DBUS_SESSION_BUS_WINDOWID=%ld\n",
	get_machine_uuid (),
	getenv ("DISPLAY"),
	address, (long)pid, (long)wid);

	fclose (f);

	return TRUE;
	}

	int
	x11_save_address (char address, pid_t pid, long wid)
	{
	Window id = set_address_in_x11 (address, pid);
	if (id != None)
	{
	if (!set_address_in_file (address, pid, id))
	return FALSE;

	if (wid != NULL)
	*wid = (long) id;
	return TRUE;
	}
	return FALSE;
	}

	int
	x11_init (void)
	{
	return open_x11 () != NULL && init_x_atoms (xdisplay);
	}

	void
	x11_handle_event (void)
	{
	if (xdisplay != NULL)
	{
	while (XPending (xdisplay))
	{
	XEvent ignored;
	XNextEvent (xdisplay, &ignored);
	}
	}
	}

	#else
	void dummy_dbus_launch_x11 (void);

	void dummy_dbus_launch_x11 (void) { }
	#endif