bus.c 19.4 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
/* -*- mode: C; c-file-style: "gnu" -*- */
/* bus.c  message bus context object
 *
 * Copyright (C) 2003 Red Hat, Inc.
 *
 * Licensed under the Academic Free License version 1.2
 * 
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include "bus.h"
#include "activation.h"
#include "connection.h"
#include "services.h"
#include "utils.h"
29
#include "policy.h"
30
#include "config-parser.h"
31 32
#include <dbus/dbus-list.h>
#include <dbus/dbus-hash.h>
33 34 35 36 37
#include <dbus/dbus-internals.h>

struct BusContext
{
  int refcount;
38
  char *type;
39
  char *address;
40
  char *pidfile;
41
  DBusLoop *loop;
42
  DBusList *servers;
43 44 45
  BusConnections *connections;
  BusActivation *activation;
  BusRegistry *registry;
46
  BusPolicy *policy;
47 48 49 50 51
  int activation_timeout;        /**< How long to wait for an activation to time out */
  int auth_timeout;              /**< How long to wait for an authentication to time out */
  int max_completed_connections;    /**< Max number of authorized connections */
  int max_incomplete_connections;   /**< Max number of incomplete connections */
  int max_connections_per_user;     /**< Max number of connections auth'd as same user */
52 53
};

54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106
static int server_data_slot = -1;
static int server_data_slot_refcount = 0;

typedef struct
{
  BusContext *context;
} BusServerData;

#define BUS_SERVER_DATA(server) (dbus_server_get_data ((server), server_data_slot))

static dbus_bool_t
server_data_slot_ref (void)
{
  if (server_data_slot < 0)
    {
      server_data_slot = dbus_server_allocate_data_slot ();
      
      if (server_data_slot < 0)
        return FALSE;

      _dbus_assert (server_data_slot_refcount == 0);
    }  

  server_data_slot_refcount += 1;

  return TRUE;
}

static void
server_data_slot_unref (void)
{
  _dbus_assert (server_data_slot_refcount > 0);

  server_data_slot_refcount -= 1;
  
  if (server_data_slot_refcount == 0)
    {
      dbus_server_free_data_slot (server_data_slot);
      server_data_slot = -1;
    }
}

static BusContext*
server_get_context (DBusServer *server)
{
  BusContext *context;
  BusServerData *bd;
  
  if (!server_data_slot_ref ())
    return NULL;

  bd = BUS_SERVER_DATA (server);
  if (bd == NULL)
107 108 109 110
    {
      server_data_slot_unref ();
      return NULL;
    }
111 112 113 114 115 116 117 118

  context = bd->context;

  server_data_slot_unref ();

  return context;
}

119
static dbus_bool_t
120 121 122 123
server_watch_callback (DBusWatch     *watch,
                       unsigned int   condition,
                       void          *data)
{
124
  DBusServer *server = data;
125

126
  return dbus_server_handle_watch (server, watch, condition);
127 128
}

129
static dbus_bool_t
130
add_server_watch (DBusWatch  *watch,
131
                  void       *data)
132
{
133 134 135 136 137
  DBusServer *server = data;
  BusContext *context;
  
  context = server_get_context (server);
  
138 139 140
  return _dbus_loop_add_watch (context->loop,
                               watch, server_watch_callback, server,
                               NULL);
141 142 143 144
}

static void
remove_server_watch (DBusWatch  *watch,
145
                     void       *data)
146
{
147 148 149 150 151
  DBusServer *server = data;
  BusContext *context;
  
  context = server_get_context (server);
  
152 153
  _dbus_loop_remove_watch (context->loop,
                           watch, server_watch_callback, server);
154 155
}

156

157 158 159 160
static void
server_timeout_callback (DBusTimeout   *timeout,
                         void          *data)
{
161
  /* can return FALSE on OOM but we just let it fire again later */
162 163 164 165 166
  dbus_timeout_handle (timeout);
}

static dbus_bool_t
add_server_timeout (DBusTimeout *timeout,
167
                    void        *data)
168
{
169 170 171 172 173
  DBusServer *server = data;
  BusContext *context;
  
  context = server_get_context (server);

174 175
  return _dbus_loop_add_timeout (context->loop,
                                 timeout, server_timeout_callback, server, NULL);
176 177 178 179
}

static void
remove_server_timeout (DBusTimeout *timeout,
180
                       void        *data)
181
{
182 183 184 185 186
  DBusServer *server = data;
  BusContext *context;
  
  context = server_get_context (server);
  
187 188
  _dbus_loop_remove_timeout (context->loop,
                             timeout, server_timeout_callback, server);
189 190
}

191 192 193 194 195 196 197 198
static void
new_connection_callback (DBusServer     *server,
                         DBusConnection *new_connection,
                         void           *data)
{
  BusContext *context = data;
  
  if (!bus_connections_setup_connection (context->connections, new_connection))
199 200
    {
      _dbus_verbose ("No memory to setup new connection\n");
201

202 203 204 205 206 207 208 209
      /* if we don't do this, it will get unref'd without
       * being disconnected... kind of strange really
       * that we have to do this, people won't get it right
       * in general.
       */
      dbus_connection_disconnect (new_connection);
    }
  
210
  /* on OOM, we won't have ref'd the connection so it will die. */
211 212
}

213 214 215 216 217 218 219 220
static void
free_server_data (void *data)
{
  BusServerData *bd = data;  
  
  dbus_free (bd);
}

221 222 223
static dbus_bool_t
setup_server (BusContext *context,
              DBusServer *server,
224
              char      **auth_mechanisms,
225
              DBusError  *error)
226
{
227
  BusServerData *bd;
228 229 230 231 232 233 234 235 236 237 238 239

  bd = dbus_new0 (BusServerData, 1);
  if (!dbus_server_set_data (server,
                             server_data_slot,
                             bd, free_server_data))
    {
      dbus_free (bd);
      BUS_SET_OOM (error);
      return FALSE;
    }

  bd->context = context;
240
  
241 242 243 244 245 246
  if (!dbus_server_set_auth_mechanisms (server, (const char**) auth_mechanisms))
    {
      BUS_SET_OOM (error);
      return FALSE;
    }
  
247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270
  dbus_server_set_new_connection_function (server,
                                           new_connection_callback,
                                           context, NULL);
  
  if (!dbus_server_set_watch_functions (server,
                                        add_server_watch,
                                        remove_server_watch,
                                        NULL,
                                        server,
                                        NULL))
    {
      BUS_SET_OOM (error);
      return FALSE;
    }

  if (!dbus_server_set_timeout_functions (server,
                                          add_server_timeout,
                                          remove_server_timeout,
                                          NULL,
                                          server, NULL))
    {
      BUS_SET_OOM (error);
      return FALSE;
    }
271
  
272 273 274
  return TRUE;
}

275
BusContext*
276
bus_context_new (const DBusString *config_file,
277
                 int               print_addr_fd,
278
                 DBusError        *error)
279 280
{
  BusContext *context;
281 282 283 284
  DBusList *link;
  DBusList **addresses;
  BusConfigParser *parser;
  DBusString full_address;
285
  const char *user, *pidfile;
286 287 288
  char **auth_mechanisms;
  DBusList **auth_mechanisms_list;
  int len;
289
  
290
  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
291

292
  if (!_dbus_string_init (&full_address))
293 294 295 296
    {
      BUS_SET_OOM (error);
      return NULL;
    }
297

298 299 300 301 302 303 304
  if (!server_data_slot_ref ())
    {
      BUS_SET_OOM (error);
      _dbus_string_free (&full_address);
      return NULL;
    }
  
305 306
  parser = NULL;
  context = NULL;
307
  auth_mechanisms = NULL;
308 309 310 311
  
  parser = bus_config_load (config_file, error);
  if (parser == NULL)
    goto failed;
312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336

  /* Check for an existing pid file. Of course this is a race;
   * we'd have to use fcntl() locks on the pid file to
   * avoid that. But we want to check for the pid file
   * before overwriting any existing sockets, etc.
   */
  pidfile = bus_config_parser_get_pidfile (parser);
  if (pidfile != NULL)
    {
      DBusString u;
      DBusStat stbuf;
      DBusError tmp_error;
      
      dbus_error_init (&tmp_error);
      _dbus_string_init_const (&u, pidfile);
      
      if (_dbus_stat (&u, &stbuf, &tmp_error))
	{
	  dbus_set_error (error, DBUS_ERROR_FAILED,
			  "The pid file \"%s\" exists, if the message bus is not running, remove this file",
			  pidfile);
	  dbus_error_free (&tmp_error);
	  goto failed;
	}
    }
337 338 339 340 341
  
  context = dbus_new0 (BusContext, 1);
  if (context == NULL)
    {
      BUS_SET_OOM (error);
342
      goto failed;
343 344 345
    }
  
  context->refcount = 1;
346

347 348 349 350 351 352
  /* we need another ref of the server data slot for the context
   * to own
   */
  if (!server_data_slot_ref ())
    _dbus_assert_not_reached ("second ref of server data slot failed");
  
353
#ifdef DBUS_BUILD_TESTS
354
  context->activation_timeout = 6000;  /* 6 seconds */
355
#else
356
  context->activation_timeout = 15000; /* 15 seconds */
357
#endif
358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373

  /* Making this long risks making a DOS attack easier, but too short
   * and legitimate auth will fail.  If interactive auth (ask user for
   * password) is allowed, then potentially it has to be quite long.
   * Ultimately it needs to come from the configuration file.
   */     
  context->auth_timeout = 3000; /* 3 seconds */

  context->max_incomplete_connections = 32;
  context->max_connections_per_user = 128;

  /* Note that max_completed_connections / max_connections_per_user
   * is the number of users that would have to work together to
   * DOS all the other users.
   */
  context->max_completed_connections = 1024;
374
  
375
  context->loop = _dbus_loop_new ();
376 377 378 379 380 381
  if (context->loop == NULL)
    {
      BUS_SET_OOM (error);
      goto failed;
    }
  
382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410
  /* Build an array of auth mechanisms */
  
  auth_mechanisms_list = bus_config_parser_get_mechanisms (parser);
  len = _dbus_list_get_length (auth_mechanisms_list);

  if (len > 0)
    {
      int i;

      auth_mechanisms = dbus_new0 (char*, len + 1);
      if (auth_mechanisms == NULL)
        goto failed;
      
      i = 0;
      link = _dbus_list_get_first_link (auth_mechanisms_list);
      while (link != NULL)
        {
          auth_mechanisms[i] = _dbus_strdup (link->data);
          if (auth_mechanisms[i] == NULL)
            goto failed;
          link = _dbus_list_get_next_link (auth_mechanisms_list, link);
        }
    }
  else
    {
      auth_mechanisms = NULL;
    }

  /* Listen on our addresses */
411 412 413 414 415 416 417 418 419 420 421
  
  addresses = bus_config_parser_get_addresses (parser);  
  
  link = _dbus_list_get_first_link (addresses);
  while (link != NULL)
    {
      DBusServer *server;
      
      server = dbus_server_listen (link->data, error);
      if (server == NULL)
        goto failed;
422
      else if (!setup_server (context, server, auth_mechanisms, error))
423 424 425 426 427 428 429 430 431 432 433
        goto failed;

      if (!_dbus_list_append (&context->servers, server))
        {
          BUS_SET_OOM (error);
          goto failed;
        }          
      
      link = _dbus_list_get_next_link (addresses, link);
    }

434 435
  /* note that type may be NULL */
  context->type = _dbus_strdup (bus_config_parser_get_type (parser));
436
  
437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459
  /* We have to build the address backward, so that
   * <listen> later in the config file have priority
   */
  link = _dbus_list_get_last_link (&context->servers);
  while (link != NULL)
    {
      char *addr;
      
      addr = dbus_server_get_address (link->data);
      if (addr == NULL)
        {
          BUS_SET_OOM (error);
          goto failed;
        }

      if (_dbus_string_get_length (&full_address) > 0)
        {
          if (!_dbus_string_append (&full_address, ";"))
            {
              BUS_SET_OOM (error);
              goto failed;
            }
        }
460

461 462 463 464 465 466 467 468 469 470 471 472
      if (!_dbus_string_append (&full_address, addr))
        {
          BUS_SET_OOM (error);
          goto failed;
        }

      dbus_free (addr);

      link = _dbus_list_get_prev_link (&context->servers, link);
    }

  if (!_dbus_string_copy_data (&full_address, &context->address))
473 474 475 476
    {
      BUS_SET_OOM (error);
      goto failed;
    }
477

478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519
  /* Note that we don't know whether the print_addr_fd is
   * one of the sockets we're using to listen on, or some
   * other random thing. But I think the answer is "don't do
   * that then"
   */
  if (print_addr_fd >= 0)
    {
      DBusString addr;
      const char *a = bus_context_get_address (context);
      int bytes;
      
      _dbus_assert (a != NULL);
      if (!_dbus_string_init (&addr))
        {
          BUS_SET_OOM (error);
          goto failed;
        }
      
      if (!_dbus_string_append (&addr, a) ||
          !_dbus_string_append (&addr, "\n"))
        {
          _dbus_string_free (&addr);
          BUS_SET_OOM (error);
          goto failed;
        }

      bytes = _dbus_string_get_length (&addr);
      if (_dbus_write (print_addr_fd, &addr, 0, bytes) != bytes)
        {
          dbus_set_error (error, DBUS_ERROR_FAILED,
                          "Printing message bus address: %s\n",
                          _dbus_strerror (errno));
          _dbus_string_free (&addr);
          goto failed;
        }

      if (print_addr_fd > 2)
        _dbus_close (print_addr_fd, NULL);

      _dbus_string_free (&addr);
    }
  
520
  /* Create activation subsystem */
521
  
522
  context->activation = bus_activation_new (context, &full_address,
523 524
                                            bus_config_parser_get_service_dirs (parser),
                                            error);
525 526 527 528 529 530 531 532 533 534 535 536 537
  if (context->activation == NULL)
    {
      _DBUS_ASSERT_ERROR_IS_SET (error);
      goto failed;
    }

  context->connections = bus_connections_new (context);
  if (context->connections == NULL)
    {
      BUS_SET_OOM (error);
      goto failed;
    }

538
  context->registry = bus_registry_new (context);
539 540 541 542 543
  if (context->registry == NULL)
    {
      BUS_SET_OOM (error);
      goto failed;
    }
544

545 546 547
  context->policy = bus_config_parser_steal_policy (parser);
  _dbus_assert (context->policy != NULL);
  
548 549 550
  /* Now become a daemon if appropriate */
  if (bus_config_parser_get_fork (parser))
    {
551 552 553 554 555 556
      DBusString u;

      if (pidfile)
        _dbus_string_init_const (&u, pidfile);
      
      if (!_dbus_become_daemon (pidfile ? &u : NULL, error))
557 558
        goto failed;
    }
559 560 561 562 563 564 565 566 567 568 569 570 571
  else
    {
      /* Need to write PID file for ourselves, not for the child process */
      if (pidfile != NULL)
        {
          DBusString u;

          _dbus_string_init_const (&u, pidfile);
          
          if (!_dbus_write_pid_file (&u, _dbus_getpid (), error))
            goto failed;
        }
    }
572 573 574

  /* keep around the pid filename so we can delete it later */
  context->pidfile = _dbus_strdup (pidfile);
575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599

  /* Here we change our credentials if required,
   * as soon as we've set up our sockets and pidfile
   */
  user = bus_config_parser_get_user (parser);
  if (user != NULL)
    {
      DBusCredentials creds;
      DBusString u;

      _dbus_string_init_const (&u, user);

      if (!_dbus_credentials_from_username (&u, &creds) ||
          creds.uid < 0 ||
          creds.gid < 0)
        {
          dbus_set_error (error, DBUS_ERROR_FAILED,
                          "Could not get UID and GID for username \"%s\"",
                          user);
          goto failed;
        }
      
      if (!_dbus_change_identity (creds.uid, creds.gid, error))
        goto failed;
    }
600
  
601 602
  bus_config_parser_unref (parser);
  _dbus_string_free (&full_address);
603
  dbus_free_string_array (auth_mechanisms);
604
  server_data_slot_unref ();
605 606 607
  
  return context;
  
608
 failed:  
609 610 611 612 613 614 615
  if (parser != NULL)
    bus_config_parser_unref (parser);

  if (context != NULL)
    bus_context_unref (context);

  _dbus_string_free (&full_address);
616
  dbus_free_string_array (auth_mechanisms);
617 618 619

  server_data_slot_unref ();
  
620 621 622
  return NULL;
}

623 624 625
static void
shutdown_server (BusContext *context,
                 DBusServer *server)
626
{
627 628
  if (server == NULL ||
      !dbus_server_get_is_connected (server))
629 630
    return;
  
631
  if (!dbus_server_set_watch_functions (server,
632
                                        NULL, NULL, NULL,
633 634 635 636
                                        context,
                                        NULL))
    _dbus_assert_not_reached ("setting watch functions to NULL failed");
  
637
  if (!dbus_server_set_timeout_functions (server,
638
                                          NULL, NULL, NULL,
639 640 641 642
                                          context,
                                          NULL))
    _dbus_assert_not_reached ("setting timeout functions to NULL failed");
  
643 644 645 646 647 648 649 650 651 652 653 654 655 656 657
  dbus_server_disconnect (server);
}

void
bus_context_shutdown (BusContext  *context)
{
  DBusList *link;

  link = _dbus_list_get_first_link (&context->servers);
  while (link != NULL)
    {
      shutdown_server (context, link->data);

      link = _dbus_list_get_next_link (&context->servers, link);
    }
658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674
}

void
bus_context_ref (BusContext *context)
{
  _dbus_assert (context->refcount > 0);
  context->refcount += 1;
}

void
bus_context_unref (BusContext *context)
{
  _dbus_assert (context->refcount > 0);
  context->refcount -= 1;

  if (context->refcount == 0)
    {
675 676
      DBusList *link;
      
677 678
      _dbus_verbose ("Finalizing bus context %p\n", context);
      
679
      bus_context_shutdown (context);
680 681 682 683 684 685

      if (context->connections)
        {
          bus_connections_unref (context->connections);
          context->connections = NULL;
        }
686
      
687
      if (context->registry)
688 689 690 691 692
        {
          bus_registry_unref (context->registry);
          context->registry = NULL;
        }
      
693
      if (context->activation)
694 695 696 697
        {
          bus_activation_unref (context->activation);
          context->activation = NULL;
        }
698 699 700

      link = _dbus_list_get_first_link (&context->servers);
      while (link != NULL)
701
        {
702 703 704
          dbus_server_unref (link->data);
          
          link = _dbus_list_get_next_link (&context->servers, link);
705
        }
706
      _dbus_list_clear (&context->servers);
707

708
      if (context->policy)
709
        {
710 711
          bus_policy_unref (context->policy);
          context->policy = NULL;
712
        }
713
      
714 715
      if (context->loop)
        {
716
          _dbus_loop_unref (context->loop);
717 718 719
          context->loop = NULL;
        }
      
720
      dbus_free (context->type);
721
      dbus_free (context->address);
722 723 724 725 726 727 728 729 730 731 732 733 734 735

      if (context->pidfile)
	{
          DBusString u;
          _dbus_string_init_const (&u, context->pidfile);

          /* Deliberately ignore errors here, since there's not much
	   * we can do about it, and we're exiting anyways.
	   */
	  _dbus_delete_file (&u, NULL);

          dbus_free (context->pidfile); 
	}

736
      dbus_free (context);
737 738

      server_data_slot_unref ();
739 740 741
    }
}

742 743 744 745 746 747 748
/* type may be NULL */
const char*
bus_context_get_type (BusContext *context)
{
  return context->type;
}

749 750 751 752 753 754
const char*
bus_context_get_address (BusContext *context)
{
  return context->address;
}

755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771
BusRegistry*
bus_context_get_registry (BusContext  *context)
{
  return context->registry;
}

BusConnections*
bus_context_get_connections (BusContext  *context)
{
  return context->connections;
}

BusActivation*
bus_context_get_activation (BusContext  *context)
{
  return context->activation;
}
772

773
DBusLoop*
774 775 776 777 778
bus_context_get_loop (BusContext *context)
{
  return context->loop;
}

779 780 781 782
dbus_bool_t
bus_context_allow_user (BusContext   *context,
                        unsigned long uid)
{
783
  return bus_policy_allow_user (context->policy, uid);
784 785
}

786 787 788
BusClientPolicy*
bus_context_create_client_policy (BusContext      *context,
                                  DBusConnection  *connection)
789
{
790
  return bus_policy_create_client_policy (context->policy, connection);
791
}
792 793 794 795 796 797 798

int
bus_context_get_activation_timeout (BusContext *context)
{
  
  return context->activation_timeout;
}