bus.c 19.9 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 29
/* -*- 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 "loop.h"
#include "activation.h"
#include "connection.h"
#include "services.h"
#include "utils.h"
30
#include "policy.h"
31
#include "config-parser.h"
32 33
#include <dbus/dbus-list.h>
#include <dbus/dbus-hash.h>
34 35 36 37 38
#include <dbus/dbus-internals.h>

struct BusContext
{
  int refcount;
39
  char *type;
40
  char *address;
41
  BusLoop *loop;
42
  DBusList *servers;
43 44 45
  BusConnections *connections;
  BusActivation *activation;
  BusRegistry *registry;
46
  DBusList *default_rules;      /**< Default policy rules */
47
  DBusList *mandatory_rules;    /**< Mandatory policy rules */
48 49
  DBusHashTable *rules_by_uid;  /**< per-UID policy rules */
  DBusHashTable *rules_by_gid;  /**< per-GID policy rules */
50 51
};

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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113
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)
    return NULL;

  context = bd->context;

  server_data_slot_unref ();

  return context;
}

114
static dbus_bool_t
115 116 117 118
server_watch_callback (DBusWatch     *watch,
                       unsigned int   condition,
                       void          *data)
{
119
  DBusServer *server = data;
120

121
  return dbus_server_handle_watch (server, watch, condition);
122 123
}

124
static dbus_bool_t
125
add_server_watch (DBusWatch  *watch,
126
                  void       *data)
127
{
128 129 130 131 132 133 134
  DBusServer *server = data;
  BusContext *context;
  
  context = server_get_context (server);
  
  return bus_loop_add_watch (context->loop,
                             watch, server_watch_callback, server,
135
                             NULL);
136 137 138 139
}

static void
remove_server_watch (DBusWatch  *watch,
140
                     void       *data)
141
{
142 143 144 145 146 147 148
  DBusServer *server = data;
  BusContext *context;
  
  context = server_get_context (server);
  
  bus_loop_remove_watch (context->loop,
                         watch, server_watch_callback, server);
149 150
}

151

152 153 154 155
static void
server_timeout_callback (DBusTimeout   *timeout,
                         void          *data)
{
156
  /* can return FALSE on OOM but we just let it fire again later */
157 158 159 160 161
  dbus_timeout_handle (timeout);
}

static dbus_bool_t
add_server_timeout (DBusTimeout *timeout,
162
                    void        *data)
163
{
164 165 166 167 168 169 170
  DBusServer *server = data;
  BusContext *context;
  
  context = server_get_context (server);

  return bus_loop_add_timeout (context->loop,
                               timeout, server_timeout_callback, server, NULL);
171 172 173 174
}

static void
remove_server_timeout (DBusTimeout *timeout,
175
                       void        *data)
176
{
177 178 179 180 181 182 183
  DBusServer *server = data;
  BusContext *context;
  
  context = server_get_context (server);
  
  bus_loop_remove_timeout (context->loop,
                           timeout, server_timeout_callback, server);
184 185
}

186 187 188 189 190 191 192 193
static void
new_connection_callback (DBusServer     *server,
                         DBusConnection *new_connection,
                         void           *data)
{
  BusContext *context = data;
  
  if (!bus_connections_setup_connection (context->connections, new_connection))
194 195
    {
      _dbus_verbose ("No memory to setup new connection\n");
196

197 198 199 200 201 202 203 204
      /* 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);
    }
  
205
  /* on OOM, we won't have ref'd the connection so it will die. */
206 207
}

208
static void
209 210
free_rule_func (void *data,
                void *user_data)
211 212 213 214 215 216
{
  BusPolicyRule *rule = data;

  bus_policy_rule_unref (rule);
}

217 218 219 220 221 222 223 224 225 226 227 228
static void
free_rule_list_func (void *data)
{
  DBusList **list = data;

  _dbus_list_foreach (list, free_rule_func, NULL);
  
  _dbus_list_clear (list);

  dbus_free (list);
}

229 230 231 232 233 234 235 236
static void
free_server_data (void *data)
{
  BusServerData *bd = data;  
  
  dbus_free (bd);
}

237 238 239
static dbus_bool_t
setup_server (BusContext *context,
              DBusServer *server,
240
              char      **auth_mechanisms,
241
              DBusError  *error)
242
{
243 244
  BusServerData *bd;
  
245 246 247 248 249 250
  if (!dbus_server_set_auth_mechanisms (server, (const char**) auth_mechanisms))
    {
      BUS_SET_OOM (error);
      return FALSE;
    }
  
251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274
  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;
    }
275 276 277 278 279 280 281 282 283
  
  bd = dbus_new0 (BusServerData, 1);
  if (!dbus_server_set_data (server,
                             server_data_slot,
                             bd, free_server_data))
    {
      dbus_free (bd);
      return FALSE;
    }
284

285 286
  bd->context = context;
  
287 288 289
  return TRUE;
}

290
BusContext*
291 292
bus_context_new (const DBusString *config_file,
                 DBusError        *error)
293 294
{
  BusContext *context;
295 296 297 298
  DBusList *link;
  DBusList **addresses;
  BusConfigParser *parser;
  DBusString full_address;
299 300 301 302
  const char *user;
  char **auth_mechanisms;
  DBusList **auth_mechanisms_list;
  int len;
303
  
304
  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
305

306
  if (!_dbus_string_init (&full_address))
307 308 309 310 311 312 313 314 315 316 317 318
    {
      BUS_SET_OOM (error);
      return NULL;
    }
  
  if (!server_data_slot_ref ())
    {
      BUS_SET_OOM (error);
      _dbus_string_free (&full_address);
      return NULL;
    }
  
319 320
  parser = NULL;
  context = NULL;
321
  auth_mechanisms = NULL;
322 323 324 325
  
  parser = bus_config_load (config_file, error);
  if (parser == NULL)
    goto failed;
326 327 328 329 330
  
  context = dbus_new0 (BusContext, 1);
  if (context == NULL)
    {
      BUS_SET_OOM (error);
331
      goto failed;
332 333 334
    }
  
  context->refcount = 1;
335

336 337 338 339 340 341 342
  context->loop = bus_loop_new ();
  if (context->loop == NULL)
    {
      BUS_SET_OOM (error);
      goto failed;
    }
  
343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371
  /* 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 */
372 373 374 375 376 377 378 379 380 381 382
  
  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;
383
      else if (!setup_server (context, server, auth_mechanisms, error))
384 385 386 387 388 389 390 391 392 393 394
        goto failed;

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

395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418
  /* Here we change our credentials if required,
   * as soon as we've set up our sockets
   */
  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;
    }
419 420 421

  /* note that type may be NULL */
  context->type = _dbus_strdup (bus_config_parser_get_type (parser));
422
  
423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445
  /* 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;
            }
        }
446

447 448 449 450 451 452 453 454 455 456 457 458
      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))
459 460 461 462
    {
      BUS_SET_OOM (error);
      goto failed;
    }
463 464

  /* Create activation subsystem */
465
  
466
  context->activation = bus_activation_new (context, &full_address,
467 468
                                            bus_config_parser_get_service_dirs (parser),
                                            error);
469 470 471 472 473 474 475 476 477 478 479 480 481
  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;
    }

482
  context->registry = bus_registry_new (context);
483 484 485 486 487 488
  if (context->registry == NULL)
    {
      BUS_SET_OOM (error);
      goto failed;
    }
  
489
  context->rules_by_uid = _dbus_hash_table_new (DBUS_HASH_ULONG,
490
                                                NULL,
491
                                                free_rule_list_func);
492 493 494 495 496 497
  if (context->rules_by_uid == NULL)
    {
      BUS_SET_OOM (error);
      goto failed;
    }

498
  context->rules_by_gid = _dbus_hash_table_new (DBUS_HASH_ULONG,
499
                                                NULL,
500
                                                free_rule_list_func);
501 502 503 504 505
  if (context->rules_by_gid == NULL)
    {
      BUS_SET_OOM (error);
      goto failed;
    }
506

507 508 509 510 511 512 513
  /* Now become a daemon if appropriate */
  if (bus_config_parser_get_fork (parser))
    {
      if (!_dbus_become_daemon (error))
        goto failed;
    }
  
514 515
  bus_config_parser_unref (parser);
  _dbus_string_free (&full_address);
516
  dbus_free_string_array (auth_mechanisms);
517 518 519
  
  return context;
  
520
 failed:  
521 522 523 524 525 526 527
  if (parser != NULL)
    bus_config_parser_unref (parser);

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

  _dbus_string_free (&full_address);
528
  dbus_free_string_array (auth_mechanisms);
529 530 531

  server_data_slot_unref ();
  
532 533 534
  return NULL;
}

535 536 537
static void
shutdown_server (BusContext *context,
                 DBusServer *server)
538
{
539 540
  if (server == NULL ||
      !dbus_server_get_is_connected (server))
541 542
    return;
  
543
  if (!dbus_server_set_watch_functions (server,
544
                                        NULL, NULL, NULL,
545 546 547 548
                                        context,
                                        NULL))
    _dbus_assert_not_reached ("setting watch functions to NULL failed");
  
549
  if (!dbus_server_set_timeout_functions (server,
550
                                          NULL, NULL, NULL,
551 552 553 554
                                          context,
                                          NULL))
    _dbus_assert_not_reached ("setting timeout functions to NULL failed");
  
555 556 557 558 559 560 561 562 563 564 565 566 567 568 569
  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);
    }
570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586
}

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)
    {
587 588
      DBusList *link;
      
589 590
      _dbus_verbose ("Finalizing bus context %p\n", context);
      
591
      bus_context_shutdown (context);
592 593 594 595 596 597

      if (context->connections)
        {
          bus_connections_unref (context->connections);
          context->connections = NULL;
        }
598
      
599
      if (context->registry)
600 601 602 603 604
        {
          bus_registry_unref (context->registry);
          context->registry = NULL;
        }
      
605
      if (context->activation)
606 607 608 609
        {
          bus_activation_unref (context->activation);
          context->activation = NULL;
        }
610 611 612

      link = _dbus_list_get_first_link (&context->servers);
      while (link != NULL)
613
        {
614 615 616
          dbus_server_unref (link->data);
          
          link = _dbus_list_get_next_link (&context->servers, link);
617
        }
618
      _dbus_list_clear (&context->servers);
619 620 621 622 623 624 625 626 627 628 629 630

      if (context->rules_by_uid)
        {
          _dbus_hash_table_unref (context->rules_by_uid);
          context->rules_by_uid = NULL;
        }

      if (context->rules_by_gid)
        {
          _dbus_hash_table_unref (context->rules_by_gid);
          context->rules_by_gid = NULL;
        }
631

632 633 634 635 636 637
      if (context->loop)
        {
          bus_loop_unref (context->loop);
          context->loop = NULL;
        }
      
638
      dbus_free (context->type);
639 640
      dbus_free (context->address);
      dbus_free (context);
641 642

      server_data_slot_unref ();
643 644 645
    }
}

646 647 648 649 650 651 652
/* type may be NULL */
const char*
bus_context_get_type (BusContext *context)
{
  return context->type;
}

653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669
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;
}
670

671 672 673 674 675 676
BusLoop*
bus_context_get_loop (BusContext *context)
{
  return context->loop;
}

677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855
static dbus_bool_t
list_allows_user (dbus_bool_t           def,
                  DBusList            **list,
                  unsigned long         uid,
                  const unsigned long  *group_ids,
                  int                   n_group_ids)
{
  DBusList *link;
  dbus_bool_t allowed;
  
  allowed = def;

  link = _dbus_list_get_first_link (list);
  while (link != NULL)
    {
      BusPolicyRule *rule = link->data;
      link = _dbus_list_get_next_link (list, link);
      
      if (rule->type == BUS_POLICY_RULE_USER)
        {
          if (rule->d.user.uid != uid)
            continue;
        }
      else if (rule->type == BUS_POLICY_RULE_GROUP)
        {
          int i;

          i = 0;
          while (i < n_group_ids)
            {
              if (rule->d.group.gid == group_ids[i])
                break;
              ++i;
            }

          if (i == n_group_ids)
            continue;
        }
      else
        continue;

      allowed = rule->allow;
    }
  
  return allowed;
}

dbus_bool_t
bus_context_allow_user (BusContext   *context,
                        unsigned long uid)
{
  dbus_bool_t allowed;
  unsigned long *group_ids;
  int n_group_ids;

  /* On OOM or error we always reject the user */
  if (!_dbus_get_groups (uid, &group_ids, &n_group_ids))
    {
      _dbus_verbose ("Did not get any groups for UID %lu\n",
                     uid);
      return FALSE;
    }
  
  allowed = FALSE;

  allowed = list_allows_user (allowed,
                              &context->default_rules,
                              uid,
                              group_ids, n_group_ids);

  allowed = list_allows_user (allowed,
                              &context->mandatory_rules,
                              uid,
                              group_ids, n_group_ids);

  dbus_free (group_ids);

  return allowed;
}

static dbus_bool_t
add_list_to_policy (DBusList       **list,
                    BusPolicy       *policy)
{
  DBusList *link;

  link = _dbus_list_get_first_link (list);
  while (link != NULL)
    {
      BusPolicyRule *rule = link->data;
      link = _dbus_list_get_next_link (list, link);

      switch (rule->type)
        {
        case BUS_POLICY_RULE_USER:
        case BUS_POLICY_RULE_GROUP:
          /* These aren't per-connection policies */
          break;

        case BUS_POLICY_RULE_OWN:
        case BUS_POLICY_RULE_SEND:
        case BUS_POLICY_RULE_RECEIVE:
          /* These are per-connection */
          if (!bus_policy_append_rule (policy, rule))
            return FALSE;
          break;
        }
    }
  
  return TRUE;
}

BusPolicy*
bus_context_create_connection_policy (BusContext      *context,
                                      DBusConnection  *connection)
{
  BusPolicy *policy;
  unsigned long uid;
  DBusList **list;

  _dbus_assert (dbus_connection_get_is_authenticated (connection));
  
  policy = bus_policy_new ();
  if (policy == NULL)
    return NULL;

  if (!add_list_to_policy (&context->default_rules,
                                      policy))
    goto failed;

  /* we avoid the overhead of looking up user's groups
   * if we don't have any group rules anyway
   */
  if (_dbus_hash_table_get_n_entries (context->rules_by_gid) > 0)
    {
      const unsigned long *groups;
      int n_groups;
      int i;
      
      if (!bus_connection_get_groups (connection, &groups, &n_groups))
        goto failed;
      
      i = 0;
      while (i < n_groups)
        {
          list = _dbus_hash_table_lookup_ulong (context->rules_by_gid,
                                                groups[i]);
          
          if (list != NULL)
            {
              if (!add_list_to_policy (list, policy))
                goto failed;
            }
          
          ++i;
        }
    }

  if (!dbus_connection_get_unix_user (connection, &uid))
    goto failed;

  list = _dbus_hash_table_lookup_ulong (context->rules_by_uid,
                                        uid);

  if (!add_list_to_policy (list, policy))
    goto failed;
  
  if (!add_list_to_policy (&context->mandatory_rules,
                           policy))
    goto failed;

  bus_policy_optimize (policy);
  
  return policy;
  
 failed:
  bus_policy_unref (policy);
  return NULL;
}