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1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-launch.c  dbus-launch utility
3  *
4  * Copyright (C) 2003, 2006 Red Hat, Inc.
5  * Copyright (C) 2006 Thiago Macieira <thiago@kde.org>
6  *
7  * Licensed under the Academic Free License version 2.1
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
22  *
23  */
24 
25 #include <config.h>
26 #include "dbus-launch.h"
27 #include <stdlib.h>
28 #include <ctype.h>
29 #include <unistd.h>
30 #include <fcntl.h>
31 #include <signal.h>
32 #include <sys/wait.h>
33 #include <errno.h>
34 #include <stdio.h>
35 #include <string.h>
36 #include <signal.h>
37 #include <stdarg.h>
38 #include <sys/select.h>
39 #include <time.h>
40 
41 #ifdef DBUS_BUILD_X11
42 #include <X11/Xlib.h>
43 extern Display *xdisplay;
44 #endif
45 
46 static char* machine_uuid = NULL;
47 
48 const char*
get_machine_uuid(void)49 get_machine_uuid (void)
50 {
51   return machine_uuid;
52 }
53 
54 static void
save_machine_uuid(const char * uuid_arg)55 save_machine_uuid (const char *uuid_arg)
56 {
57   if (strlen (uuid_arg) != 32)
58     {
59       fprintf (stderr, "machine ID '%s' looks like it's the wrong length, should be 32 hex digits",
60                uuid_arg);
61       exit (1);
62     }
63 
64   machine_uuid = xstrdup (uuid_arg);
65 }
66 
67 #define UUID_MAXLEN 40
68 /* Read the machine uuid from file if needed. Returns TRUE if machine_uuid is
69  * set after this function */
70 static int
read_machine_uuid_if_needed(void)71 read_machine_uuid_if_needed (void)
72 {
73   FILE *f;
74   char uuid[UUID_MAXLEN];
75   size_t len;
76   int ret = FALSE;
77 
78   if (machine_uuid != NULL)
79     return TRUE;
80 
81   f = fopen (DBUS_MACHINE_UUID_FILE, "r");
82   if (f == NULL)
83     return FALSE;
84 
85   if (fgets (uuid, UUID_MAXLEN, f) == NULL)
86     goto out;
87 
88   len = strlen (uuid);
89   if (len < 32)
90     goto out;
91 
92   /* rstrip the read uuid */
93   while (len > 31 && isspace(uuid[len - 1]))
94     len--;
95 
96   if (len != 32)
97     goto out;
98 
99   uuid[len] = '\0';
100   machine_uuid = xstrdup (uuid);
101   verbose ("UID: %s\n", machine_uuid);
102   ret = TRUE;
103 
104 out:
105   fclose(f);
106   return ret;
107 }
108 
109 
110 void
verbose(const char * format,...)111 verbose (const char *format,
112          ...)
113 {
114   va_list args;
115   static int verbose = TRUE;
116   static int verbose_initted = FALSE;
117 
118   /* things are written a bit oddly here so that
119    * in the non-verbose case we just have the one
120    * conditional and return immediately.
121    */
122   if (!verbose)
123     return;
124 
125   if (!verbose_initted)
126     {
127       verbose = getenv ("DBUS_VERBOSE") != NULL;
128       verbose_initted = TRUE;
129       if (!verbose)
130         return;
131     }
132 
133   fprintf (stderr, "%lu: ", (unsigned long) getpid ());
134 
135   va_start (args, format);
136   vfprintf (stderr, format, args);
137   va_end (args);
138 }
139 
140 static void
usage(int ecode)141 usage (int ecode)
142 {
143   fprintf (stderr, "dbus-launch [--version] [--help] [--sh-syntax] [--csh-syntax] [--auto-syntax] [--exit-with-session]\n");
144   exit (ecode);
145 }
146 
147 static void
version(void)148 version (void)
149 {
150   printf ("D-Bus Message Bus Launcher %s\n"
151           "Copyright (C) 2003 Red Hat, Inc.\n"
152           "This is free software; see the source for copying conditions.\n"
153           "There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n",
154           VERSION);
155   exit (0);
156 }
157 
158 char *
xstrdup(const char * str)159 xstrdup (const char *str)
160 {
161   int len;
162   char *copy;
163 
164   if (str == NULL)
165     return NULL;
166 
167   len = strlen (str);
168 
169   copy = malloc (len + 1);
170   if (copy == NULL)
171     return NULL;
172 
173   memcpy (copy, str, len + 1);
174 
175   return copy;
176 }
177 
178 typedef enum
179 {
180   READ_STATUS_OK,    /**< Read succeeded */
181   READ_STATUS_ERROR, /**< Some kind of error */
182   READ_STATUS_EOF    /**< EOF returned */
183 } ReadStatus;
184 
185 static ReadStatus
read_line(int fd,char * buf,size_t maxlen)186 read_line (int        fd,
187            char      *buf,
188            size_t     maxlen)
189 {
190   size_t bytes = 0;
191   ReadStatus retval;
192 
193   memset (buf, '\0', maxlen);
194   maxlen -= 1; /* ensure nul term */
195 
196   retval = READ_STATUS_OK;
197 
198   while (TRUE)
199     {
200       ssize_t chunk;
201       size_t to_read;
202 
203     again:
204       to_read = maxlen - bytes;
205 
206       if (to_read == 0)
207         break;
208 
209       chunk = read (fd,
210                     buf + bytes,
211                     to_read);
212       if (chunk < 0 && errno == EINTR)
213         goto again;
214 
215       if (chunk < 0)
216         {
217           retval = READ_STATUS_ERROR;
218           break;
219         }
220       else if (chunk == 0)
221         {
222           retval = READ_STATUS_EOF;
223           break; /* EOF */
224         }
225       else /* chunk > 0 */
226 	bytes += chunk;
227     }
228 
229   if (retval == READ_STATUS_EOF &&
230       bytes > 0)
231     retval = READ_STATUS_OK;
232 
233   /* whack newline */
234   if (retval != READ_STATUS_ERROR &&
235       bytes > 0 &&
236       buf[bytes-1] == '\n')
237     buf[bytes-1] = '\0';
238 
239   return retval;
240 }
241 
242 static ReadStatus
read_pid(int fd,pid_t * buf)243 read_pid (int        fd,
244           pid_t     *buf)
245 {
246   size_t bytes = 0;
247   ReadStatus retval;
248 
249   retval = READ_STATUS_OK;
250 
251   while (TRUE)
252     {
253       ssize_t chunk;
254       size_t to_read;
255 
256     again:
257       to_read = sizeof (pid_t) - bytes;
258 
259       if (to_read == 0)
260         break;
261 
262       chunk = read (fd,
263                     ((char*)buf) + bytes,
264                     to_read);
265       if (chunk < 0 && errno == EINTR)
266         goto again;
267 
268       if (chunk < 0)
269         {
270           retval = READ_STATUS_ERROR;
271           break;
272         }
273       else if (chunk == 0)
274         {
275           retval = READ_STATUS_EOF;
276           break; /* EOF */
277         }
278       else /* chunk > 0 */
279 	bytes += chunk;
280     }
281 
282   return retval;
283 }
284 
285 static void
do_write(int fd,const void * buf,size_t count)286 do_write (int fd, const void *buf, size_t count)
287 {
288   size_t bytes_written;
289   int ret;
290 
291   bytes_written = 0;
292 
293  again:
294 
295   ret = write (fd, ((const char*)buf) + bytes_written, count - bytes_written);
296 
297   if (ret < 0)
298     {
299       if (errno == EINTR)
300         goto again;
301       else
302         {
303           fprintf (stderr, "Failed to write data to pipe! %s\n",
304                    strerror (errno));
305           exit (1); /* give up, we suck */
306         }
307     }
308   else
309     bytes_written += ret;
310 
311   if (bytes_written < count)
312     goto again;
313 }
314 
315 static void
write_pid(int fd,pid_t pid)316 write_pid (int   fd,
317            pid_t pid)
318 {
319   do_write (fd, &pid, sizeof (pid));
320 }
321 
322 static int
do_waitpid(pid_t pid)323 do_waitpid (pid_t pid)
324 {
325   int ret;
326 
327  again:
328   ret = waitpid (pid, NULL, 0);
329 
330   if (ret < 0 &&
331       errno == EINTR)
332     goto again;
333 
334   return ret;
335 }
336 
337 static pid_t bus_pid_to_kill = -1;
338 
339 static void
kill_bus(void)340 kill_bus(void)
341 {
342   verbose ("Killing message bus and exiting babysitter\n");
343   kill (bus_pid_to_kill, SIGTERM);
344   sleep (3);
345   kill (bus_pid_to_kill, SIGKILL);
346 }
347 
348 void
kill_bus_and_exit(int exitcode)349 kill_bus_and_exit (int exitcode)
350 {
351   /* in case these point to any NFS mounts, get rid of them immediately */
352   close (0);
353   close (1);
354   close (2);
355 
356   kill_bus();
357 
358   exit (exitcode);
359 }
360 
361 static void
print_variables(const char * bus_address,pid_t bus_pid,long bus_wid,int c_shell_syntax,int bourne_shell_syntax,int binary_syntax)362 print_variables (const char *bus_address, pid_t bus_pid, long bus_wid,
363 		 int c_shell_syntax, int bourne_shell_syntax,
364 		 int binary_syntax)
365 {
366   if (binary_syntax)
367     {
368       do_write (1, bus_address, strlen (bus_address) + 1);
369       do_write (1, &bus_pid, sizeof bus_pid);
370       do_write (1, &bus_wid, sizeof bus_wid);
371       return;
372     }
373   else if (c_shell_syntax)
374     {
375       printf ("setenv DBUS_SESSION_BUS_ADDRESS '%s';\n", bus_address);
376       printf ("set DBUS_SESSION_BUS_PID=%ld;\n", (long) bus_pid);
377       if (bus_wid)
378         printf ("set DBUS_SESSION_BUS_WINDOWID=%ld;\n", (long) bus_wid);
379       fflush (stdout);
380     }
381   else if (bourne_shell_syntax)
382     {
383       printf ("DBUS_SESSION_BUS_ADDRESS='%s';\n", bus_address);
384       printf ("export DBUS_SESSION_BUS_ADDRESS;\n");
385       printf ("DBUS_SESSION_BUS_PID=%ld;\n", (long) bus_pid);
386       if (bus_wid)
387         printf ("DBUS_SESSION_BUS_WINDOWID=%ld;\n", (long) bus_wid);
388       fflush (stdout);
389     }
390   else
391     {
392       printf ("DBUS_SESSION_BUS_ADDRESS=%s\n", bus_address);
393       printf ("DBUS_SESSION_BUS_PID=%ld\n", (long) bus_pid);
394       if (bus_wid)
395 	printf ("DBUS_SESSION_BUS_WINDOWID=%ld\n", (long) bus_wid);
396       fflush (stdout);
397     }
398 }
399 
400 static int got_sighup = FALSE;
401 
402 static void
signal_handler(int sig)403 signal_handler (int sig)
404 {
405   switch (sig)
406     {
407 #ifdef SIGHUP
408     case SIGHUP:
409 #endif
410     case SIGINT:
411     case SIGTERM:
412       got_sighup = TRUE;
413       break;
414     }
415 }
416 
417 static void
kill_bus_when_session_ends(void)418 kill_bus_when_session_ends (void)
419 {
420   int tty_fd;
421   int x_fd;
422   fd_set read_set;
423   fd_set err_set;
424   struct sigaction act;
425   sigset_t empty_mask;
426 
427   /* install SIGHUP handler */
428   got_sighup = FALSE;
429   sigemptyset (&empty_mask);
430   act.sa_handler = signal_handler;
431   act.sa_mask    = empty_mask;
432   act.sa_flags   = 0;
433   sigaction (SIGHUP,  &act, NULL);
434   sigaction (SIGTERM,  &act, NULL);
435   sigaction (SIGINT,  &act, NULL);
436 
437 #ifdef DBUS_BUILD_X11
438   x11_init();
439   if (xdisplay != NULL)
440     {
441       x_fd = ConnectionNumber (xdisplay);
442     }
443   else
444     x_fd = -1;
445 #else
446   x_fd = -1;
447 #endif
448 
449   if (isatty (0))
450     tty_fd = 0;
451   else
452     tty_fd = -1;
453 
454   if (tty_fd >= 0)
455     verbose ("stdin isatty(), monitoring it\n");
456   else
457     verbose ("stdin was not a TTY, not monitoring it\n");
458 
459   if (tty_fd < 0 && x_fd < 0)
460     {
461       fprintf (stderr, "No terminal on standard input and no X display; cannot attach message bus to session lifetime\n");
462       exit (1);
463     }
464 
465   while (TRUE)
466     {
467 #ifdef DBUS_BUILD_X11
468       /* Dump events on the floor, and let
469        * IO error handler run if we lose
470        * the X connection. It's important to
471        * run this before going into select() since
472        * we might have queued outgoing messages or
473        * events.
474        */
475       x11_handle_event ();
476 #endif
477 
478       FD_ZERO (&read_set);
479       FD_ZERO (&err_set);
480 
481       if (tty_fd >= 0)
482         {
483           FD_SET (tty_fd, &read_set);
484           FD_SET (tty_fd, &err_set);
485         }
486 
487       if (x_fd >= 0)
488         {
489           FD_SET (x_fd, &read_set);
490           FD_SET (x_fd, &err_set);
491         }
492 
493       select (MAX (tty_fd, x_fd) + 1,
494               &read_set, NULL, &err_set, NULL);
495 
496       if (got_sighup)
497         {
498           verbose ("Got SIGHUP, exiting\n");
499           kill_bus_and_exit (0);
500         }
501 
502 #ifdef DBUS_BUILD_X11
503       /* Events will be processed before we select again
504        */
505       if (x_fd >= 0)
506         verbose ("X fd condition reading = %d error = %d\n",
507                  FD_ISSET (x_fd, &read_set),
508                  FD_ISSET (x_fd, &err_set));
509 #endif
510 
511       if (tty_fd >= 0)
512         {
513           if (FD_ISSET (tty_fd, &read_set))
514             {
515               int bytes_read;
516               char discard[512];
517 
518               verbose ("TTY ready for reading\n");
519 
520               bytes_read = read (tty_fd, discard, sizeof (discard));
521 
522               verbose ("Read %d bytes from TTY errno = %d\n",
523                        bytes_read, errno);
524 
525               if (bytes_read == 0)
526                 kill_bus_and_exit (0); /* EOF */
527               else if (bytes_read < 0 && errno != EINTR)
528                 {
529                   /* This shouldn't happen I don't think; to avoid
530                    * spinning on the fd forever we exit.
531                    */
532                   fprintf (stderr, "dbus-launch: error reading from stdin: %s\n",
533                            strerror (errno));
534                   kill_bus_and_exit (0);
535                 }
536             }
537           else if (FD_ISSET (tty_fd, &err_set))
538             {
539               verbose ("TTY has error condition\n");
540 
541               kill_bus_and_exit (0);
542             }
543         }
544     }
545 }
546 
547 static void
babysit(int exit_with_session,pid_t child_pid,int read_bus_pid_fd)548 babysit (int   exit_with_session,
549          pid_t child_pid,
550          int   read_bus_pid_fd)  /* read pid from here */
551 {
552   int ret;
553   int dev_null_fd;
554   const char *s;
555 
556   verbose ("babysitting, exit_with_session = %d, child_pid = %ld, read_bus_pid_fd = %d\n",
557            exit_with_session, (long) child_pid, read_bus_pid_fd);
558 
559   /* We chdir ("/") since we are persistent and daemon-like, and fork
560    * again so dbus-launch can reap the parent.  However, we don't
561    * setsid() or close fd 0 because the idea is to remain attached
562    * to the tty and the X server in order to kill the message bus
563    * when the session ends.
564    */
565 
566   if (chdir ("/") < 0)
567     {
568       fprintf (stderr, "Could not change to root directory: %s\n",
569                strerror (errno));
570       exit (1);
571     }
572 
573   /* Close stdout/stderr so we don't block an "eval" or otherwise
574    * lock up. stdout is still chaining through to dbus-launch
575    * and in turn to the parent shell.
576    */
577   dev_null_fd = open ("/dev/null", O_RDWR);
578   if (dev_null_fd >= 0)
579     {
580       if (!exit_with_session)
581         dup2 (dev_null_fd, 0);
582       dup2 (dev_null_fd, 1);
583       s = getenv ("DBUS_DEBUG_OUTPUT");
584       if (s == NULL || *s == '\0')
585         dup2 (dev_null_fd, 2);
586     }
587   else
588     {
589       fprintf (stderr, "Failed to open /dev/null: %s\n",
590                strerror (errno));
591       /* continue, why not */
592     }
593 
594   ret = fork ();
595 
596   if (ret < 0)
597     {
598       fprintf (stderr, "fork() failed in babysitter: %s\n",
599                strerror (errno));
600       exit (1);
601     }
602 
603   if (ret > 0)
604     {
605       /* Parent reaps pre-fork part of bus daemon, then exits and is
606        * reaped so the babysitter isn't a zombie
607        */
608 
609       verbose ("=== Babysitter's intermediate parent continues again\n");
610 
611       if (do_waitpid (child_pid) < 0)
612         {
613           /* shouldn't happen */
614           fprintf (stderr, "Failed waitpid() waiting for bus daemon's parent\n");
615           exit (1);
616         }
617 
618       verbose ("Babysitter's intermediate parent exiting\n");
619 
620       exit (0);
621     }
622 
623   /* Child continues */
624   verbose ("=== Babysitter process created\n");
625 
626   verbose ("Reading PID from bus\n");
627 
628   switch (read_pid (read_bus_pid_fd, &bus_pid_to_kill))
629     {
630     case READ_STATUS_OK:
631       break;
632     case READ_STATUS_EOF:
633       fprintf (stderr, "EOF in dbus-launch reading PID from bus daemon\n");
634       exit (1);
635       break;
636     case READ_STATUS_ERROR:
637       fprintf (stderr, "Error in dbus-launch reading PID from bus daemon: %s\n",
638 	       strerror (errno));
639       exit (1);
640       break;
641     }
642 
643   verbose ("Got PID %ld from daemon\n",
644            (long) bus_pid_to_kill);
645 
646   if (exit_with_session)
647     {
648       /* Bus is now started and launcher has needed info;
649        * we connect to X display and tty and wait to
650        * kill bus if requested.
651        */
652 
653       kill_bus_when_session_ends ();
654     }
655 
656   verbose ("Babysitter exiting\n");
657 
658   exit (0);
659 }
660 
661 static void
do_close_stderr(void)662 do_close_stderr (void)
663 {
664   int fd;
665 
666   fflush (stderr);
667 
668   /* dbus-launch is a Unix-only program, so we can rely on /dev/null being there.
669    * We're including unistd.h and we're dealing with sh/csh launch sequences...
670    */
671   fd = open ("/dev/null", O_RDWR);
672   if (fd == -1)
673     {
674       fprintf (stderr, "Internal error: cannot open /dev/null: %s", strerror (errno));
675       exit (1);
676     }
677 
678   close (2);
679   if (dup2 (fd, 2) == -1)
680     {
681       /* error; we can't report an error anymore... */
682       exit (1);
683     }
684   close (fd);
685 }
686 
687 static void
pass_info(const char * runprog,const char * bus_address,pid_t bus_pid,long bus_wid,int c_shell_syntax,int bourne_shell_syntax,int binary_syntax,int argc,char ** argv,int remaining_args)688 pass_info (const char *runprog, const char *bus_address, pid_t bus_pid,
689            long bus_wid, int c_shell_syntax, int bourne_shell_syntax,
690            int binary_syntax,
691            int argc, char **argv, int remaining_args)
692 {
693   if (runprog)
694     {
695       char *envvar;
696       char **args;
697       int i;
698 
699       envvar = malloc (strlen ("DBUS_SESSION_BUS_ADDRESS=") +
700           strlen (bus_address) + 1);
701       args = malloc (sizeof (char *) * ((argc-remaining_args)+2));
702 
703       if (envvar == NULL || args == NULL)
704         goto oom;
705 
706      args[0] = xstrdup (runprog);
707       if (!args[0])
708         goto oom;
709      for (i = 1; i <= (argc-remaining_args); i++)
710       {
711         size_t len = strlen (argv[remaining_args+i-1])+1;
712         args[i] = malloc (len);
713         if (!args[i])
714           goto oom;
715         strncpy (args[i], argv[remaining_args+i-1], len);
716        }
717      args[i] = NULL;
718 
719      strcpy (envvar, "DBUS_SESSION_BUS_ADDRESS=");
720      strcat (envvar, bus_address);
721      putenv (envvar);
722 
723      execvp (runprog, args);
724      fprintf (stderr, "Couldn't exec %s: %s\n", runprog, strerror (errno));
725      exit (1);
726     }
727    else
728     {
729       print_variables (bus_address, bus_pid, bus_wid, c_shell_syntax,
730          bourne_shell_syntax, binary_syntax);
731     }
732   verbose ("dbus-launch exiting\n");
733 
734   fflush (stdout);
735   fflush (stderr);
736   close (1);
737   close (2);
738   exit (0);
739 oom:
740   fprintf (stderr, "Out of memory!");
741   exit (1);
742 }
743 
744 #define READ_END  0
745 #define WRITE_END 1
746 
747 int
main(int argc,char ** argv)748 main (int argc, char **argv)
749 {
750   const char *prev_arg;
751   const char *shname;
752   const char *runprog = NULL;
753   int remaining_args = 0;
754   int exit_with_session;
755   int binary_syntax = FALSE;
756   int c_shell_syntax = FALSE;
757   int bourne_shell_syntax = FALSE;
758   int auto_shell_syntax = FALSE;
759   int autolaunch = FALSE;
760   int requires_arg = FALSE;
761   int close_stderr = FALSE;
762   int i;
763   int ret;
764   int bus_pid_to_launcher_pipe[2];
765   int bus_pid_to_babysitter_pipe[2];
766   int bus_address_to_launcher_pipe[2];
767   char *config_file;
768 
769   exit_with_session = FALSE;
770   config_file = NULL;
771 
772   prev_arg = NULL;
773   i = 1;
774   while (i < argc)
775     {
776       const char *arg = argv[i];
777 
778       if (strcmp (arg, "--help") == 0 ||
779           strcmp (arg, "-h") == 0 ||
780           strcmp (arg, "-?") == 0)
781         usage (0);
782       else if (strcmp (arg, "--auto-syntax") == 0)
783         auto_shell_syntax = TRUE;
784       else if (strcmp (arg, "-c") == 0 ||
785                strcmp (arg, "--csh-syntax") == 0)
786         c_shell_syntax = TRUE;
787       else if (strcmp (arg, "-s") == 0 ||
788                strcmp (arg, "--sh-syntax") == 0)
789         bourne_shell_syntax = TRUE;
790       else if (strcmp (arg, "--binary-syntax") == 0)
791         binary_syntax = TRUE;
792       else if (strcmp (arg, "--version") == 0)
793         version ();
794       else if (strcmp (arg, "--exit-with-session") == 0)
795         exit_with_session = TRUE;
796       else if (strcmp (arg, "--close-stderr") == 0)
797         close_stderr = TRUE;
798       else if (strstr (arg, "--autolaunch=") == arg)
799         {
800           const char *s;
801 
802           if (autolaunch)
803             {
804               fprintf (stderr, "--autolaunch given twice\n");
805               exit (1);
806             }
807 
808           autolaunch = TRUE;
809 
810           s = strchr (arg, '=');
811           ++s;
812 
813           save_machine_uuid (s);
814         }
815       else if (prev_arg &&
816                strcmp (prev_arg, "--autolaunch") == 0)
817         {
818           if (autolaunch)
819             {
820               fprintf (stderr, "--autolaunch given twice\n");
821               exit (1);
822             }
823 
824           autolaunch = TRUE;
825 
826           save_machine_uuid (arg);
827 	  requires_arg = FALSE;
828         }
829       else if (strcmp (arg, "--autolaunch") == 0)
830 	requires_arg = TRUE;
831       else if (strstr (arg, "--config-file=") == arg)
832         {
833           const char *file;
834 
835           if (config_file != NULL)
836             {
837               fprintf (stderr, "--config-file given twice\n");
838               exit (1);
839             }
840 
841           file = strchr (arg, '=');
842           ++file;
843 
844           config_file = xstrdup (file);
845         }
846       else if (prev_arg &&
847                strcmp (prev_arg, "--config-file") == 0)
848         {
849           if (config_file != NULL)
850             {
851               fprintf (stderr, "--config-file given twice\n");
852               exit (1);
853             }
854 
855           config_file = xstrdup (arg);
856 	  requires_arg = FALSE;
857         }
858       else if (strcmp (arg, "--config-file") == 0)
859 	requires_arg = TRUE;
860       else if (arg[0] == '-')
861         {
862           if (strcmp (arg, "--") != 0)
863             {
864               fprintf (stderr, "Option `%s' is unknown.\n", arg);
865               exit (1);
866             }
867           else
868             {
869               runprog = argv[i+1];
870               remaining_args = i+2;
871               break;
872             }
873         }
874       else
875 	{
876 	  runprog = arg;
877 	  remaining_args = i+1;
878 	  break;
879 	}
880 
881       prev_arg = arg;
882 
883       ++i;
884     }
885   if (requires_arg)
886     {
887       fprintf (stderr, "Option `%s' requires an argument.\n", prev_arg);
888       exit (1);
889     }
890 
891   if (auto_shell_syntax)
892     {
893       if ((shname = getenv ("SHELL")) != NULL)
894        {
895          if (!strncmp (shname + strlen (shname) - 3, "csh", 3))
896            c_shell_syntax = TRUE;
897          else
898            bourne_shell_syntax = TRUE;
899        }
900       else
901        bourne_shell_syntax = TRUE;
902     }
903 
904   if (exit_with_session)
905     verbose ("--exit-with-session enabled\n");
906 
907   if (autolaunch)
908     {
909 #ifndef DBUS_BUILD_X11
910       fprintf (stderr, "Autolaunch requested, but X11 support not compiled in.\n"
911 	       "Cannot continue.\n");
912       exit (1);
913 #else
914       char *address;
915       pid_t pid;
916       long wid;
917 
918       if (get_machine_uuid () == NULL)
919         {
920           fprintf (stderr, "Machine UUID not provided as arg to --autolaunch\n");
921           exit (1);
922         }
923 
924       verbose ("Autolaunch enabled (using X11).\n");
925       if (!exit_with_session)
926 	{
927 	  verbose ("--exit-with-session automatically enabled\n");
928 	  exit_with_session = TRUE;
929 	}
930 
931       if (!x11_init ())
932 	{
933 	  fprintf (stderr, "Autolaunch error: X11 initialization failed.\n");
934 	  exit (1);
935 	}
936 
937       if (!x11_get_address (&address, &pid, &wid))
938 	{
939 	  fprintf (stderr, "Autolaunch error: X11 communication error.\n");
940 	  exit (1);
941 	}
942 
943       if (address != NULL)
944 	{
945 	  verbose ("dbus-daemon is already running. Returning existing parameters.\n");
946 	  pass_info (runprog, address, pid, wid, c_shell_syntax,
947 			   bourne_shell_syntax, binary_syntax, argc, argv, remaining_args);
948 	  exit (0);
949 	}
950     }
951    else if (read_machine_uuid_if_needed())
952     {
953       x11_init();
954 #endif
955     }
956 
957 
958   if (pipe (bus_pid_to_launcher_pipe) < 0 ||
959       pipe (bus_address_to_launcher_pipe) < 0 ||
960       pipe (bus_pid_to_babysitter_pipe) < 0)
961     {
962       fprintf (stderr,
963                "Failed to create pipe: %s\n",
964                strerror (errno));
965       exit (1);
966     }
967 
968   ret = fork ();
969   if (ret < 0)
970     {
971       fprintf (stderr, "Failed to fork: %s\n",
972                strerror (errno));
973       exit (1);
974     }
975 
976   if (ret == 0)
977     {
978       /* Child */
979 #define MAX_FD_LEN 64
980       char write_pid_fd_as_string[MAX_FD_LEN];
981       char write_address_fd_as_string[MAX_FD_LEN];
982 
983 #ifdef DBUS_BUILD_X11
984       xdisplay = NULL;
985 #endif
986 
987       if (close_stderr)
988 	do_close_stderr ();
989 
990       verbose ("=== Babysitter's intermediate parent created\n");
991 
992       /* Fork once more to create babysitter */
993 
994       ret = fork ();
995       if (ret < 0)
996         {
997           fprintf (stderr, "Failed to fork: %s\n",
998                    strerror (errno));
999           exit (1);
1000         }
1001 
1002       if (ret > 0)
1003         {
1004           /* In babysitter */
1005           verbose ("=== Babysitter's intermediate parent continues\n");
1006 
1007           close (bus_pid_to_launcher_pipe[READ_END]);
1008 	  close (bus_pid_to_launcher_pipe[WRITE_END]);
1009           close (bus_address_to_launcher_pipe[READ_END]);
1010           close (bus_address_to_launcher_pipe[WRITE_END]);
1011           close (bus_pid_to_babysitter_pipe[WRITE_END]);
1012 
1013           /* babysit() will fork *again*
1014            * and will also reap the pre-forked bus
1015            * daemon
1016            */
1017           babysit (exit_with_session, ret,
1018                    bus_pid_to_babysitter_pipe[READ_END]);
1019           exit (0);
1020         }
1021 
1022       verbose ("=== Bus exec process created\n");
1023 
1024       /* Now we are the bus process (well, almost;
1025        * dbus-daemon itself forks again)
1026        */
1027       close (bus_pid_to_launcher_pipe[READ_END]);
1028       close (bus_address_to_launcher_pipe[READ_END]);
1029       close (bus_pid_to_babysitter_pipe[READ_END]);
1030       close (bus_pid_to_babysitter_pipe[WRITE_END]);
1031 
1032       sprintf (write_pid_fd_as_string,
1033                "%d", bus_pid_to_launcher_pipe[WRITE_END]);
1034 
1035       sprintf (write_address_fd_as_string,
1036                "%d", bus_address_to_launcher_pipe[WRITE_END]);
1037 
1038       verbose ("Calling exec()\n");
1039 
1040 #ifdef DBUS_BUILD_TESTS
1041       /* exec from testdir */
1042       if (getenv("DBUS_USE_TEST_BINARY") != NULL)
1043         {
1044           execl (TEST_BUS_BINARY,
1045                  TEST_BUS_BINARY,
1046                  "--fork",
1047                  "--print-pid", write_pid_fd_as_string,
1048                  "--print-address", write_address_fd_as_string,
1049                  config_file ? "--config-file" : "--session",
1050                  config_file, /* has to be last in this varargs list */
1051                  NULL);
1052 
1053           fprintf (stderr,
1054                    "Failed to execute test message bus daemon %s: %s. Will try again with the system path.\n",
1055                    TEST_BUS_BINARY, strerror (errno));
1056         }
1057  #endif /* DBUS_BUILD_TESTS */
1058 
1059       execl (DBUS_DAEMONDIR"/dbus-daemon",
1060              DBUS_DAEMONDIR"/dbus-daemon",
1061              "--fork",
1062              "--print-pid", write_pid_fd_as_string,
1063              "--print-address", write_address_fd_as_string,
1064              config_file ? "--config-file" : "--session",
1065              config_file, /* has to be last in this varargs list */
1066              NULL);
1067 
1068       fprintf (stderr,
1069                "Failed to execute message bus daemon %s: %s.  Will try again without full path.\n",
1070                DBUS_DAEMONDIR"/dbus-daemon", strerror (errno));
1071 
1072       /*
1073        * If it failed, try running without full PATH.  Note this is needed
1074        * because the build process builds the run-with-tmp-session-bus.conf
1075        * file and the dbus-daemon will not be in the install location during
1076        * build time.
1077        */
1078       execlp ("dbus-daemon",
1079               "dbus-daemon",
1080               "--fork",
1081               "--print-pid", write_pid_fd_as_string,
1082               "--print-address", write_address_fd_as_string,
1083               config_file ? "--config-file" : "--session",
1084               config_file, /* has to be last in this varargs list */
1085               NULL);
1086 
1087       fprintf (stderr,
1088                "Failed to execute message bus daemon: %s\n",
1089                strerror (errno));
1090       exit (1);
1091     }
1092   else
1093     {
1094       /* Parent */
1095 #define MAX_PID_LEN 64
1096       pid_t bus_pid;
1097       char bus_address[MAX_ADDR_LEN];
1098       char buf[MAX_PID_LEN];
1099       char *end;
1100       long wid = 0;
1101       long val;
1102       int ret2;
1103 
1104       verbose ("=== Parent dbus-launch continues\n");
1105 
1106       close (bus_pid_to_launcher_pipe[WRITE_END]);
1107       close (bus_address_to_launcher_pipe[WRITE_END]);
1108       close (bus_pid_to_babysitter_pipe[READ_END]);
1109 
1110       verbose ("Waiting for babysitter's intermediate parent\n");
1111 
1112       /* Immediately reap parent of babysitter
1113        * (which was created just for us to reap)
1114        */
1115       if (do_waitpid (ret) < 0)
1116         {
1117           fprintf (stderr, "Failed to waitpid() for babysitter intermediate process: %s\n",
1118                    strerror (errno));
1119           exit (1);
1120         }
1121 
1122       verbose ("Reading address from bus\n");
1123 
1124       /* Read the pipe data, print, and exit */
1125       switch (read_line (bus_address_to_launcher_pipe[READ_END],
1126                          bus_address, MAX_ADDR_LEN))
1127         {
1128         case READ_STATUS_OK:
1129           break;
1130         case READ_STATUS_EOF:
1131           fprintf (stderr, "EOF in dbus-launch reading address from bus daemon\n");
1132           exit (1);
1133           break;
1134         case READ_STATUS_ERROR:
1135           fprintf (stderr, "Error in dbus-launch reading address from bus daemon: %s\n",
1136                    strerror (errno));
1137           exit (1);
1138           break;
1139         }
1140 
1141       close (bus_address_to_launcher_pipe[READ_END]);
1142 
1143       verbose ("Reading PID from daemon\n");
1144       /* Now read data */
1145       switch (read_line (bus_pid_to_launcher_pipe[READ_END], buf, MAX_PID_LEN))
1146 	{
1147 	case READ_STATUS_OK:
1148 	  break;
1149 	case READ_STATUS_EOF:
1150 	  fprintf (stderr, "EOF reading PID from bus daemon\n");
1151 	  exit (1);
1152 	  break;
1153 	case READ_STATUS_ERROR:
1154 	  fprintf (stderr, "Error reading PID from bus daemon: %s\n",
1155 		   strerror (errno));
1156 	  exit (1);
1157 	  break;
1158 	}
1159 
1160       end = NULL;
1161       val = strtol (buf, &end, 0);
1162       if (buf == end || end == NULL)
1163 	{
1164 	  fprintf (stderr, "Failed to parse bus PID \"%s\": %s\n",
1165 		   buf, strerror (errno));
1166 	  exit (1);
1167 	}
1168 
1169       bus_pid = val;
1170 
1171       close (bus_pid_to_launcher_pipe[READ_END]);
1172 
1173 #ifdef DBUS_BUILD_X11
1174       if (xdisplay != NULL)
1175         {
1176           verbose("Saving x11 address\n");
1177           ret2 = x11_save_address (bus_address, bus_pid, &wid);
1178           /* Only get an existing dbus session when autolaunching */
1179           if (autolaunch)
1180             {
1181               if (ret2 == 0)
1182                 {
1183                   char *address = NULL;
1184                   /* another window got added. Return its address */
1185                   bus_pid_to_kill = bus_pid;
1186                   if (x11_get_address (&address, &bus_pid, &wid)
1187                        && address != NULL)
1188                     {
1189                       verbose ("dbus-daemon is already running. Returning existing parameters.\n");
1190                       /* Kill the old bus */
1191                       kill_bus();
1192                       pass_info (runprog, address, bus_pid, wid,
1193                          c_shell_syntax, bourne_shell_syntax, binary_syntax,
1194                          argc, argv, remaining_args);
1195                     }
1196                   }
1197               if (ret2 < 0)
1198                 {
1199                   fprintf (stderr, "Error saving bus information.\n");
1200                   bus_pid_to_kill = bus_pid;
1201                   kill_bus_and_exit (1);
1202                 }
1203             }
1204         }
1205 #endif
1206 
1207       /* Forward the pid to the babysitter */
1208       write_pid (bus_pid_to_babysitter_pipe[WRITE_END], bus_pid);
1209       close (bus_pid_to_babysitter_pipe[WRITE_END]);
1210 
1211        pass_info (runprog, bus_address, bus_pid, wid, c_shell_syntax,
1212               bourne_shell_syntax, binary_syntax, argc, argv, remaining_args);
1213     }
1214 
1215   return 0;
1216 }
1217