/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* dbus-launch.h dbus-launch utility
*
* Copyright (C) 2006 Thiago Macieira <thiago@kde.org>
*
* 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 (¤t_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