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1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* main.c  main() for message bus
3  *
4  * Copyright (C) 2003 Red Hat, Inc.
5  *
6  * Licensed under the Academic Free License version 2.1
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
21  *
22  */
23 
24 #include <config.h>
25 #include "bus.h"
26 #include "driver.h"
27 #include <dbus/dbus-internals.h>
28 #include <dbus/dbus-watch.h>
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #ifdef HAVE_SIGNAL_H
33 #include <signal.h>
34 #endif
35 #ifdef HAVE_ERRNO_H
36 #include <errno.h>
37 #endif
38 #include "selinux.h"
39 
40 static BusContext *context;
41 
42 static int reload_pipe[2];
43 #define RELOAD_READ_END 0
44 #define RELOAD_WRITE_END 1
45 
46 static void close_reload_pipe (void);
47 
48 static void
signal_handler(int sig)49 signal_handler (int sig)
50 {
51 
52   switch (sig)
53     {
54 #ifdef DBUS_BUS_ENABLE_DNOTIFY_ON_LINUX
55     case SIGIO:
56       /* explicit fall-through */
57 #endif /* DBUS_BUS_ENABLE_DNOTIFY_ON_LINUX  */
58 #ifdef SIGHUP
59     case SIGHUP:
60       {
61         DBusString str;
62         _dbus_string_init_const (&str, "foo");
63         if ((reload_pipe[RELOAD_WRITE_END] > 0) &&
64             !_dbus_write_socket (reload_pipe[RELOAD_WRITE_END], &str, 0, 1))
65           {
66             _dbus_warn ("Unable to write to reload pipe.\n");
67             close_reload_pipe ();
68           }
69       }
70       break;
71 #endif
72     }
73 }
74 
75 static void
usage(void)76 usage (void)
77 {
78   fprintf (stderr, DBUS_DAEMON_NAME " [--version] [--session] [--system] [--config-file=FILE] [--print-address[=DESCRIPTOR]] [--print-pid[=DESCRIPTOR]] [--fork] [--nofork] [--introspect] [--address=ADDRESS] [--systemd-activation]\n");
79   exit (1);
80 }
81 
82 static void
version(void)83 version (void)
84 {
85   printf ("D-Bus Message Bus Daemon %s\n"
86           "Copyright (C) 2002, 2003 Red Hat, Inc., CodeFactory AB, and others\n"
87           "This is free software; see the source for copying conditions.\n"
88           "There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n",
89           DBUS_VERSION_STRING);
90   exit (0);
91 }
92 
93 static void
introspect(void)94 introspect (void)
95 {
96   DBusString xml;
97   const char *v_STRING;
98 
99   if (!_dbus_string_init (&xml))
100     goto oom;
101 
102   if (!bus_driver_generate_introspect_string (&xml))
103     {
104       _dbus_string_free (&xml);
105       goto oom;
106     }
107 
108   v_STRING = _dbus_string_get_const_data (&xml);
109   printf ("%s\n", v_STRING);
110 
111   exit (0);
112 
113  oom:
114   _dbus_warn ("Can not introspect - Out of memory\n");
115   exit (1);
116 }
117 
118 static void
check_two_config_files(const DBusString * config_file,const char * extra_arg)119 check_two_config_files (const DBusString *config_file,
120                         const char       *extra_arg)
121 {
122   if (_dbus_string_get_length (config_file) > 0)
123     {
124       fprintf (stderr, "--%s specified but configuration file %s already requested\n",
125                extra_arg, _dbus_string_get_const_data (config_file));
126       exit (1);
127     }
128 }
129 
130 static void
check_two_addresses(const DBusString * address,const char * extra_arg)131 check_two_addresses (const DBusString *address,
132                      const char       *extra_arg)
133 {
134   if (_dbus_string_get_length (address) > 0)
135     {
136       fprintf (stderr, "--%s specified but address %s already requested\n",
137                extra_arg, _dbus_string_get_const_data (address));
138       exit (1);
139     }
140 }
141 
142 static void
check_two_addr_descriptors(const DBusString * addr_fd,const char * extra_arg)143 check_two_addr_descriptors (const DBusString *addr_fd,
144                             const char       *extra_arg)
145 {
146   if (_dbus_string_get_length (addr_fd) > 0)
147     {
148       fprintf (stderr, "--%s specified but printing address to %s already requested\n",
149                extra_arg, _dbus_string_get_const_data (addr_fd));
150       exit (1);
151     }
152 }
153 
154 static void
check_two_pid_descriptors(const DBusString * pid_fd,const char * extra_arg)155 check_two_pid_descriptors (const DBusString *pid_fd,
156                            const char       *extra_arg)
157 {
158   if (_dbus_string_get_length (pid_fd) > 0)
159     {
160       fprintf (stderr, "--%s specified but printing pid to %s already requested\n",
161                extra_arg, _dbus_string_get_const_data (pid_fd));
162       exit (1);
163     }
164 }
165 
166 static dbus_bool_t
handle_reload_watch(DBusWatch * watch,unsigned int flags,void * data)167 handle_reload_watch (DBusWatch    *watch,
168 		     unsigned int  flags,
169 		     void         *data)
170 {
171   DBusError error;
172   DBusString str;
173 
174   while (!_dbus_string_init (&str))
175     _dbus_wait_for_memory ();
176 
177   if ((reload_pipe[RELOAD_READ_END] > 0) &&
178       _dbus_read_socket (reload_pipe[RELOAD_READ_END], &str, 1) != 1)
179     {
180       _dbus_warn ("Couldn't read from reload pipe.\n");
181       close_reload_pipe ();
182       return TRUE;
183     }
184   _dbus_string_free (&str);
185 
186   /* this can only fail if we don't understand the config file
187    * or OOM.  Either way we should just stick with the currently
188    * loaded config.
189    */
190   dbus_error_init (&error);
191   if (! bus_context_reload_config (context, &error))
192     {
193       _DBUS_ASSERT_ERROR_IS_SET (&error);
194       _dbus_assert (dbus_error_has_name (&error, DBUS_ERROR_FAILED) ||
195 		    dbus_error_has_name (&error, DBUS_ERROR_NO_MEMORY));
196       _dbus_warn ("Unable to reload configuration: %s\n",
197 		  error.message);
198       dbus_error_free (&error);
199     }
200   return TRUE;
201 }
202 
203 static dbus_bool_t
reload_watch_callback(DBusWatch * watch,unsigned int condition,void * data)204 reload_watch_callback (DBusWatch    *watch,
205 		       unsigned int  condition,
206 		       void         *data)
207 {
208   return dbus_watch_handle (watch, condition);
209 }
210 
211 static void
setup_reload_pipe(DBusLoop * loop)212 setup_reload_pipe (DBusLoop *loop)
213 {
214   DBusError error;
215   DBusWatch *watch;
216 
217   dbus_error_init (&error);
218 
219   if (!_dbus_full_duplex_pipe (&reload_pipe[0], &reload_pipe[1],
220 			       TRUE, &error))
221     {
222       _dbus_warn ("Unable to create reload pipe: %s\n",
223 		  error.message);
224       dbus_error_free (&error);
225       exit (1);
226     }
227 
228   watch = _dbus_watch_new (reload_pipe[RELOAD_READ_END],
229 			   DBUS_WATCH_READABLE, TRUE,
230 			   handle_reload_watch, NULL, NULL);
231 
232   if (watch == NULL)
233     {
234       _dbus_warn ("Unable to create reload watch: %s\n",
235 		  error.message);
236       dbus_error_free (&error);
237       exit (1);
238     }
239 
240   if (!_dbus_loop_add_watch (loop, watch, reload_watch_callback,
241 			     NULL, NULL))
242     {
243       _dbus_warn ("Unable to add reload watch to main loop: %s\n",
244 		  error.message);
245       dbus_error_free (&error);
246       exit (1);
247     }
248 
249 }
250 
251 static void
close_reload_pipe(void)252 close_reload_pipe (void)
253 {
254     _dbus_close_socket (reload_pipe[RELOAD_READ_END], NULL);
255     reload_pipe[RELOAD_READ_END] = -1;
256 
257     _dbus_close_socket (reload_pipe[RELOAD_WRITE_END], NULL);
258     reload_pipe[RELOAD_WRITE_END] = -1;
259 }
260 
261 int
main(int argc,char ** argv)262 main (int argc, char **argv)
263 {
264   DBusError error;
265   DBusString config_file;
266   DBusString address;
267   DBusString addr_fd;
268   DBusString pid_fd;
269   const char *prev_arg;
270   DBusPipe print_addr_pipe;
271   DBusPipe print_pid_pipe;
272   int i;
273   dbus_bool_t print_address;
274   dbus_bool_t print_pid;
275   dbus_bool_t is_session_bus;
276   int force_fork;
277   dbus_bool_t systemd_activation;
278 
279   if (!_dbus_string_init (&config_file))
280     return 1;
281 
282   if (!_dbus_string_init (&address))
283     return 1;
284 
285   if (!_dbus_string_init (&addr_fd))
286     return 1;
287 
288   if (!_dbus_string_init (&pid_fd))
289     return 1;
290 
291   print_address = FALSE;
292   print_pid = FALSE;
293   is_session_bus = FALSE;
294   force_fork = FORK_FOLLOW_CONFIG_FILE;
295   systemd_activation = FALSE;
296 
297   prev_arg = NULL;
298   i = 1;
299   while (i < argc)
300     {
301       const char *arg = argv[i];
302 
303       if (strcmp (arg, "--help") == 0 ||
304           strcmp (arg, "-h") == 0 ||
305           strcmp (arg, "-?") == 0)
306         usage ();
307       else if (strcmp (arg, "--version") == 0)
308         version ();
309       else if (strcmp (arg, "--introspect") == 0)
310         introspect ();
311       else if (strcmp (arg, "--nofork") == 0)
312         force_fork = FORK_NEVER;
313       else if (strcmp (arg, "--fork") == 0)
314         force_fork = FORK_ALWAYS;
315       else if (strcmp (arg, "--systemd-activation") == 0)
316         systemd_activation = TRUE;
317       else if (strcmp (arg, "--system") == 0)
318         {
319           check_two_config_files (&config_file, "system");
320 
321           if (!_dbus_append_system_config_file (&config_file))
322             exit (1);
323         }
324       else if (strcmp (arg, "--session") == 0)
325         {
326           check_two_config_files (&config_file, "session");
327 
328           if (!_dbus_append_session_config_file (&config_file))
329             exit (1);
330         }
331       else if (strstr (arg, "--config-file=") == arg)
332         {
333           const char *file;
334 
335           check_two_config_files (&config_file, "config-file");
336 
337           file = strchr (arg, '=');
338           ++file;
339 
340           if (!_dbus_string_append (&config_file, file))
341             exit (1);
342         }
343       else if (prev_arg &&
344                strcmp (prev_arg, "--config-file") == 0)
345         {
346           check_two_config_files (&config_file, "config-file");
347 
348           if (!_dbus_string_append (&config_file, arg))
349             exit (1);
350         }
351       else if (strcmp (arg, "--config-file") == 0)
352         ; /* wait for next arg */
353       else if (strstr (arg, "--address=") == arg)
354         {
355           const char *file;
356 
357           check_two_addresses (&address, "address");
358 
359           file = strchr (arg, '=');
360           ++file;
361 
362           if (!_dbus_string_append (&address, file))
363             exit (1);
364         }
365       else if (prev_arg &&
366                strcmp (prev_arg, "--address") == 0)
367         {
368           check_two_addresses (&address, "address");
369 
370           if (!_dbus_string_append (&address, arg))
371             exit (1);
372         }
373       else if (strcmp (arg, "--address") == 0)
374         ; /* wait for next arg */
375       else if (strstr (arg, "--print-address=") == arg)
376         {
377           const char *desc;
378 
379           check_two_addr_descriptors (&addr_fd, "print-address");
380 
381           desc = strchr (arg, '=');
382           ++desc;
383 
384           if (!_dbus_string_append (&addr_fd, desc))
385             exit (1);
386 
387           print_address = TRUE;
388         }
389       else if (prev_arg &&
390                strcmp (prev_arg, "--print-address") == 0)
391         {
392           check_two_addr_descriptors (&addr_fd, "print-address");
393 
394           if (!_dbus_string_append (&addr_fd, arg))
395             exit (1);
396 
397           print_address = TRUE;
398         }
399       else if (strcmp (arg, "--print-address") == 0)
400         print_address = TRUE; /* and we'll get the next arg if appropriate */
401       else if (strstr (arg, "--print-pid=") == arg)
402         {
403           const char *desc;
404 
405           check_two_pid_descriptors (&pid_fd, "print-pid");
406 
407           desc = strchr (arg, '=');
408           ++desc;
409 
410           if (!_dbus_string_append (&pid_fd, desc))
411             exit (1);
412 
413           print_pid = TRUE;
414         }
415       else if (prev_arg &&
416                strcmp (prev_arg, "--print-pid") == 0)
417         {
418           check_two_pid_descriptors (&pid_fd, "print-pid");
419 
420           if (!_dbus_string_append (&pid_fd, arg))
421             exit (1);
422 
423           print_pid = TRUE;
424         }
425       else if (strcmp (arg, "--print-pid") == 0)
426         print_pid = TRUE; /* and we'll get the next arg if appropriate */
427       else
428         usage ();
429 
430       prev_arg = arg;
431 
432       ++i;
433     }
434 
435   if (_dbus_string_get_length (&config_file) == 0)
436     {
437       fprintf (stderr, "No configuration file specified.\n");
438       usage ();
439     }
440 
441   _dbus_pipe_invalidate (&print_addr_pipe);
442   if (print_address)
443     {
444       _dbus_pipe_init_stdout (&print_addr_pipe);
445       if (_dbus_string_get_length (&addr_fd) > 0)
446         {
447           long val;
448           int end;
449           if (!_dbus_string_parse_int (&addr_fd, 0, &val, &end) ||
450               end != _dbus_string_get_length (&addr_fd) ||
451               val < 0 || val > _DBUS_INT_MAX)
452             {
453               fprintf (stderr, "Invalid file descriptor: \"%s\"\n",
454                        _dbus_string_get_const_data (&addr_fd));
455               exit (1);
456             }
457 
458           _dbus_pipe_init (&print_addr_pipe, val);
459         }
460     }
461   _dbus_string_free (&addr_fd);
462 
463   _dbus_pipe_invalidate (&print_pid_pipe);
464   if (print_pid)
465     {
466       _dbus_pipe_init_stdout (&print_pid_pipe);
467       if (_dbus_string_get_length (&pid_fd) > 0)
468         {
469           long val;
470           int end;
471           if (!_dbus_string_parse_int (&pid_fd, 0, &val, &end) ||
472               end != _dbus_string_get_length (&pid_fd) ||
473               val < 0 || val > _DBUS_INT_MAX)
474             {
475               fprintf (stderr, "Invalid file descriptor: \"%s\"\n",
476                        _dbus_string_get_const_data (&pid_fd));
477               exit (1);
478             }
479 
480           _dbus_pipe_init (&print_pid_pipe, val);
481         }
482     }
483   _dbus_string_free (&pid_fd);
484 
485   if (!bus_selinux_pre_init ())
486     {
487       _dbus_warn ("SELinux pre-initialization failed\n");
488       exit (1);
489     }
490 
491   dbus_error_init (&error);
492   context = bus_context_new (&config_file, force_fork,
493                              &print_addr_pipe, &print_pid_pipe,
494                              _dbus_string_get_length(&address) > 0 ? &address : NULL,
495                              systemd_activation,
496                              &error);
497   _dbus_string_free (&config_file);
498   if (context == NULL)
499     {
500       _dbus_warn ("Failed to start message bus: %s\n",
501                   error.message);
502       dbus_error_free (&error);
503       exit (1);
504     }
505 
506   is_session_bus = bus_context_get_type(context) != NULL
507       && strcmp(bus_context_get_type(context),"session") == 0;
508 
509   if (is_session_bus)
510     _dbus_daemon_publish_session_bus_address (bus_context_get_address (context));
511 
512   /* bus_context_new() closes the print_addr_pipe and
513    * print_pid_pipe
514    */
515 
516   setup_reload_pipe (bus_context_get_loop (context));
517 
518 #ifdef SIGHUP
519   _dbus_set_signal_handler (SIGHUP, signal_handler);
520 #endif
521 #ifdef DBUS_BUS_ENABLE_DNOTIFY_ON_LINUX
522   _dbus_set_signal_handler (SIGIO, signal_handler);
523 #endif /* DBUS_BUS_ENABLE_DNOTIFY_ON_LINUX */
524 
525   _dbus_verbose ("We are on D-Bus...\n");
526   _dbus_loop_run (bus_context_get_loop (context));
527 
528   bus_context_shutdown (context);
529   bus_context_unref (context);
530   bus_selinux_shutdown ();
531 
532   if (is_session_bus)
533     _dbus_daemon_unpublish_session_bus_address ();
534 
535   return 0;
536 }
537