bus/connection.c

   1 /* -*- mode: C; c-file-style: "gnu" -*- */
   2 /* connection.c  Client connections
   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  *
  22  */
  23 #include "connection.h"
  24 #include "dispatch.h"
  25 #include "policy.h"
  26 #include "services.h"
  27 #include "utils.h"
  28 #include "signals.h"
  29 #include "expirelist.h"
  30 #include "selinux.h"
  31 #include <dbus/dbus-list.h>
  32 #include <dbus/dbus-hash.h>
  33 #include <dbus/dbus-timeout.h>
  34 #include <dbus/dbus-userdb.h>
  35
  36 static void bus_connection_remove_transactions (DBusConnection *connection);
  37
  38 typedef struct
  39 {
  40   BusExpireItem expire_item;
  41
  42   DBusConnection *will_get_reply;
  43   DBusConnection *will_send_reply;
  44
  45   dbus_uint32_t reply_serial;
  46
  47 } BusPendingReply;
  48
  49 struct BusConnections
  50 {
  51   int refcount;
  52   DBusList *completed;  /**< List of all completed connections */
  53   int n_completed;      /**< Length of completed list */
  54   DBusList *incomplete; /**< List of all not-yet-active connections */
  55   int n_incomplete;     /**< Length of incomplete list */
  56   BusContext *context;
  57   DBusHashTable *completed_by_user; /**< Number of completed connections for each UID */
  58   DBusTimeout *expire_timeout; /**< Timeout for expiring incomplete connections. */
  59   int stamp;                   /**< Incrementing number */
  60   BusExpireList *pending_replies; /**< List of pending replies */
  61 };
  62
  63 static dbus_int32_t connection_data_slot = -1;
  64
  65 typedef struct
  66 {
  67   BusConnections *connections;
  68   DBusList *link_in_connection_list;
  69   DBusConnection *connection;
  70   DBusList *services_owned;
  71   int n_services_owned;
  72   DBusList *match_rules;
  73   int n_match_rules;
  74   char *name;
  75   DBusList *transaction_messages; /**< Stuff we need to send as part of a transaction */
  76   DBusMessage *oom_message;
  77   DBusPreallocatedSend *oom_preallocated;
  78   BusClientPolicy *policy;
  79
  80   BusSELinuxID *selinux_id;
  81
  82   long connection_tv_sec;  /**< Time when we connected (seconds component) */
  83   long connection_tv_usec; /**< Time when we connected (microsec component) */
  84   int stamp;               /**< connections->stamp last time we were traversed */
  85 } BusConnectionData;
  86
  87 static dbus_bool_t bus_pending_reply_expired (BusExpireList *list,
  88                                               DBusList      *link,
  89                                               void          *data);
  90
  91 static void bus_connection_drop_pending_replies (BusConnections  *connections,
  92                                                  DBusConnection  *connection);
  93
  94 static dbus_bool_t expire_incomplete_timeout (void *data);
  95
  96 #define BUS_CONNECTION_DATA(connection) (dbus_connection_get_data ((connection), connection_data_slot))
  97
  98 static DBusLoop*
  99 connection_get_loop (DBusConnection *connection)
 100 {
 101   BusConnectionData *d;
 102
 103   d = BUS_CONNECTION_DATA (connection);
 104
 105   return bus_context_get_loop (d->connections->context);
 106 }
 107
 108
 109 static int
 110 get_connections_for_uid (BusConnections *connections,
 111                          dbus_uid_t      uid)
 112 {
 113   void *val;
 114   int current_count;
 115
 116   /* val is NULL is 0 when it isn't in the hash yet */
 117
 118   val = _dbus_hash_table_lookup_ulong (connections->completed_by_user,
 119                                        uid);
 120
 121   current_count = _DBUS_POINTER_TO_INT (val);
 122
 123   return current_count;
 124 }
 125
 126 static dbus_bool_t
 127 adjust_connections_for_uid (BusConnections *connections,
 128                             dbus_uid_t      uid,
 129                             int             adjustment)
 130 {
 131   int current_count;
 132
 133   current_count = get_connections_for_uid (connections, uid);
 134
 135   _dbus_verbose ("Adjusting connection count for UID " DBUS_UID_FORMAT
 136                  ": was %d adjustment %d making %d\n",
 137                  uid, current_count, adjustment, current_count + adjustment);
 138
 139   _dbus_assert (current_count >= 0);
 140
 141   current_count += adjustment;
 142
 143   _dbus_assert (current_count >= 0);
 144
 145   if (current_count == 0)
 146     {
 147       _dbus_hash_table_remove_ulong (connections->completed_by_user, uid);
 148       return TRUE;
 149     }
 150   else
 151     {
 152       dbus_bool_t retval;
 153
 154       retval = _dbus_hash_table_insert_ulong (connections->completed_by_user,
 155                                               uid, _DBUS_INT_TO_POINTER (current_count));
 156
 157       /* only positive adjustment can fail as otherwise
 158        * a hash entry should already exist
 159        */
 160       _dbus_assert (adjustment > 0 ||
 161                     (adjustment <= 0 && retval));
 162
 163       return retval;
 164     }
 165 }
 166
 167 void
 168 bus_connection_disconnected (DBusConnection *connection)
 169 {
 170   BusConnectionData *d;
 171   BusService *service;
 172   BusMatchmaker *matchmaker;
 173
 174   d = BUS_CONNECTION_DATA (connection);
 175   _dbus_assert (d != NULL);
 176
 177   _dbus_verbose ("%s disconnected, dropping all service ownership and releasing\n",
 178                  d->name ? d->name : "(inactive)");
 179
 180   /* Delete our match rules */
 181   if (d->n_match_rules > 0)
 182     {
 183       matchmaker = bus_context_get_matchmaker (d->connections->context);
 184       bus_matchmaker_disconnected (matchmaker, connection);
 185     }
 186
 187   /* Drop any service ownership. Unfortunately, this requires
 188    * memory allocation and there doesn't seem to be a good way to
 189    * handle it other than sleeping; we can't "fail" the operation of
 190    * disconnecting a client, and preallocating a broadcast "service is
 191    * now gone" message for every client-service pair seems kind of
 192    * involved.
 193    */
 194   while ((service = _dbus_list_get_last (&d->services_owned)))
 195     {
 196       BusTransaction *transaction;
 197       DBusError error;
 198
 199     retry:
 200
 201       dbus_error_init (&error);
 202
 203       while ((transaction = bus_transaction_new (d->connections->context)) == NULL)
 204         _dbus_wait_for_memory ();
 205
 206       if (!bus_service_remove_owner (service, connection,
 207                                      transaction, &error))
 208         {
 209           _DBUS_ASSERT_ERROR_IS_SET (&error);
 210
 211           if (dbus_error_has_name (&error, DBUS_ERROR_NO_MEMORY))
 212             {
 213               dbus_error_free (&error);
 214               bus_transaction_cancel_and_free (transaction);
 215               _dbus_wait_for_memory ();
 216               goto retry;
 217             }
 218           else
 219             {
 220               _dbus_verbose ("Failed to remove service owner: %s %s\n",
 221                              error.name, error.message);
 222               _dbus_assert_not_reached ("Removing service owner failed for non-memory-related reason");
 223             }
 224         }
 225
 226       bus_transaction_execute_and_free (transaction);
 227     }
 228
 229   bus_dispatch_remove_connection (connection);
 230
 231   /* no more watching */
 232   if (!dbus_connection_set_watch_functions (connection,
 233                                             NULL, NULL, NULL,
 234                                             connection,
 235                                             NULL))
 236     _dbus_assert_not_reached ("setting watch functions to NULL failed");
 237
 238   if (!dbus_connection_set_timeout_functions (connection,
 239                                               NULL, NULL, NULL,
 240                                               connection,
 241                                               NULL))
 242     _dbus_assert_not_reached ("setting timeout functions to NULL failed");
 243
 244   dbus_connection_set_unix_user_function (connection,
 245                                           NULL, NULL, NULL);
 246
 247   dbus_connection_set_dispatch_status_function (connection,
 248                                                 NULL, NULL, NULL);
 249
 250   bus_connection_remove_transactions (connection);
 251
 252   if (d->link_in_connection_list != NULL)
 253     {
 254       if (d->name != NULL)
 255         {
 256           unsigned long uid;
 257
 258           _dbus_list_remove_link (&d->connections->completed, d->link_in_connection_list);
 259           d->link_in_connection_list = NULL;
 260           d->connections->n_completed -= 1;
 261
 262           if (dbus_connection_get_unix_user (connection, &uid))
 263             {
 264               if (!adjust_connections_for_uid (d->connections,
 265                                                uid, -1))
 266                 _dbus_assert_not_reached ("adjusting downward should never fail");
 267             }
 268         }
 269       else
 270         {
 271           _dbus_list_remove_link (&d->connections->incomplete, d->link_in_connection_list);
 272           d->link_in_connection_list = NULL;
 273           d->connections->n_incomplete -= 1;
 274         }
 275
 276       _dbus_assert (d->connections->n_incomplete >= 0);
 277       _dbus_assert (d->connections->n_completed >= 0);
 278     }
 279
 280   bus_connection_drop_pending_replies (d->connections, connection);
 281
 282   /* frees "d" as side effect */
 283   dbus_connection_set_data (connection,
 284                             connection_data_slot,
 285                             NULL, NULL);
 286
 287   dbus_connection_unref (connection);
 288 }
 289
 290 static dbus_bool_t
 291 connection_watch_callback (DBusWatch     *watch,
 292                            unsigned int   condition,
 293                            void          *data)
 294 {
 295  /* FIXME this can be done in dbus-mainloop.c
 296   * if the code in activation.c for the babysitter
 297   * watch handler is fixed.
 298   */
 299
 300 #if 0
 301   _dbus_verbose ("Calling handle_watch\n");
 302 #endif
 303   return dbus_watch_handle (watch, condition);
 304 }
 305
 306 static dbus_bool_t
 307 add_connection_watch (DBusWatch      *watch,
 308                       void           *data)
 309 {
 310   DBusConnection *connection = data;
 311
 312   return _dbus_loop_add_watch (connection_get_loop (connection),
 313                                watch, connection_watch_callback, connection,
 314                                NULL);
 315 }
 316
 317 static void
 318 remove_connection_watch (DBusWatch      *watch,
 319                          void           *data)
 320 {
 321   DBusConnection *connection = data;
 322
 323   _dbus_loop_remove_watch (connection_get_loop (connection),
 324                            watch, connection_watch_callback, connection);
 325 }
 326
 327 static void
 328 connection_timeout_callback (DBusTimeout   *timeout,
 329                              void          *data)
 330 {
 331   /* DBusConnection *connection = data; */
 332
 333   /* can return FALSE on OOM but we just let it fire again later */
 334   dbus_timeout_handle (timeout);
 335 }
 336
 337 static dbus_bool_t
 338 add_connection_timeout (DBusTimeout    *timeout,
 339                         void           *data)
 340 {
 341   DBusConnection *connection = data;
 342
 343   return _dbus_loop_add_timeout (connection_get_loop (connection),
 344                                  timeout, connection_timeout_callback, connection, NULL);
 345 }
 346
 347 static void
 348 remove_connection_timeout (DBusTimeout    *timeout,
 349                            void           *data)
 350 {
 351   DBusConnection *connection = data;
 352
 353   _dbus_loop_remove_timeout (connection_get_loop (connection),
 354                              timeout, connection_timeout_callback, connection);
 355 }
 356
 357 static void
 358 dispatch_status_function (DBusConnection    *connection,
 359                           DBusDispatchStatus new_status,
 360                           void              *data)
 361 {
 362   DBusLoop *loop = data;
 363
 364   if (new_status != DBUS_DISPATCH_COMPLETE)
 365     {
 366       while (!_dbus_loop_queue_dispatch (loop, connection))
 367         _dbus_wait_for_memory ();
 368     }
 369 }
 370
 371 static dbus_bool_t
 372 allow_user_function (DBusConnection *connection,
 373                      unsigned long   uid,
 374                      void           *data)
 375 {
 376   BusConnectionData *d;
 377
 378   d = BUS_CONNECTION_DATA (connection);
 379
 380   _dbus_assert (d != NULL);
 381
 382   return bus_context_allow_user (d->connections->context, uid);
 383 }
 384
 385 static void
 386 free_connection_data (void *data)
 387 {
 388   BusConnectionData *d = data;
 389
 390   /* services_owned should be NULL since we should be disconnected */
 391   _dbus_assert (d->services_owned == NULL);
 392   _dbus_assert (d->n_services_owned == 0);
 393   /* similarly */
 394   _dbus_assert (d->transaction_messages == NULL);
 395
 396   if (d->oom_preallocated)
 397     dbus_connection_free_preallocated_send (d->connection, d->oom_preallocated);
 398
 399   if (d->oom_message)
 400     dbus_message_unref (d->oom_message);
 401
 402   if (d->policy)
 403     bus_client_policy_unref (d->policy);
 404
 405   if (d->selinux_id)
 406     bus_selinux_id_unref (d->selinux_id);
 407
 408   dbus_free (d->name);
 409
 410   dbus_free (d);
 411 }
 412
 413 static void
 414 call_timeout_callback (DBusTimeout   *timeout,
 415                        void          *data)
 416 {
 417   /* can return FALSE on OOM but we just let it fire again later */
 418   dbus_timeout_handle (timeout);
 419 }
 420
 421 BusConnections*
 422 bus_connections_new (BusContext *context)
 423 {
 424   BusConnections *connections;
 425
 426   if (!dbus_connection_allocate_data_slot (&connection_data_slot))
 427     goto failed_0;
 428
 429   connections = dbus_new0 (BusConnections, 1);
 430   if (connections == NULL)
 431     goto failed_1;
 432
 433   connections->completed_by_user = _dbus_hash_table_new (DBUS_HASH_ULONG,
 434                                                          NULL, NULL);
 435   if (connections->completed_by_user == NULL)
 436     goto failed_2;
 437
 438   connections->expire_timeout = _dbus_timeout_new (100, /* irrelevant */
 439                                                    expire_incomplete_timeout,
 440                                                    connections, NULL);
 441   if (connections->expire_timeout == NULL)
 442     goto failed_3;
 443
 444   _dbus_timeout_set_enabled (connections->expire_timeout, FALSE);
 445
 446   connections->pending_replies = bus_expire_list_new (bus_context_get_loop (context),
 447                                                       bus_context_get_reply_timeout (context),
 448                                                       bus_pending_reply_expired,
 449                                                       connections);
 450   if (connections->pending_replies == NULL)
 451     goto failed_4;
 452
 453   if (!_dbus_loop_add_timeout (bus_context_get_loop (context),
 454                                connections->expire_timeout,
 455                                call_timeout_callback, NULL, NULL))
 456     goto failed_5;
 457
 458   connections->refcount = 1;
 459   connections->context = context;
 460
 461   return connections;
 462
 463  failed_5:
 464   bus_expire_list_free (connections->pending_replies);
 465  failed_4:
 466   _dbus_timeout_unref (connections->expire_timeout);
 467  failed_3:
 468   _dbus_hash_table_unref (connections->completed_by_user);
 469  failed_2:
 470   dbus_free (connections);
 471  failed_1:
 472   dbus_connection_free_data_slot (&connection_data_slot);
 473  failed_0:
 474   return NULL;
 475 }
 476
 477 BusConnections *
 478 bus_connections_ref (BusConnections *connections)
 479 {
 480   _dbus_assert (connections->refcount > 0);
 481   connections->refcount += 1;
 482
 483   return connections;
 484 }
 485
 486 void
 487 bus_connections_unref (BusConnections *connections)
 488 {
 489   _dbus_assert (connections->refcount > 0);
 490   connections->refcount -= 1;
 491   if (connections->refcount == 0)
 492     {
 493       /* drop all incomplete */
 494       while (connections->incomplete != NULL)
 495         {
 496           DBusConnection *connection;
 497
 498           connection = connections->incomplete->data;
 499
 500           dbus_connection_ref (connection);
 501           dbus_connection_close (connection);
 502           bus_connection_disconnected (connection);
 503           dbus_connection_unref (connection);
 504         }
 505
 506       _dbus_assert (connections->n_incomplete == 0);
 507
 508       /* drop all real connections */
 509       while (connections->completed != NULL)
 510         {
 511           DBusConnection *connection;
 512
 513           connection = connections->completed->data;
 514
 515           dbus_connection_ref (connection);
 516           dbus_connection_close (connection);
 517           bus_connection_disconnected (connection);
 518           dbus_connection_unref (connection);
 519         }
 520
 521       _dbus_assert (connections->n_completed == 0);
 522
 523       bus_expire_list_free (connections->pending_replies);
 524
 525       _dbus_loop_remove_timeout (bus_context_get_loop (connections->context),
 526                                  connections->expire_timeout,
 527                                  call_timeout_callback, NULL);
 528
 529       _dbus_timeout_unref (connections->expire_timeout);
 530
 531       _dbus_hash_table_unref (connections->completed_by_user);
 532
 533       dbus_free (connections);
 534
 535       dbus_connection_free_data_slot (&connection_data_slot);
 536     }
 537 }
 538
 539 dbus_bool_t
 540 bus_connections_setup_connection (BusConnections *connections,
 541                                   DBusConnection *connection)
 542 {
 543   BusConnectionData *d;
 544   dbus_bool_t retval;
 545   DBusError error;
 546
 547   d = dbus_new0 (BusConnectionData, 1);
 548
 549   if (d == NULL)
 550     return FALSE;
 551
 552   d->connections = connections;
 553   d->connection = connection;
 554
 555   _dbus_get_current_time (&d->connection_tv_sec,
 556                           &d->connection_tv_usec);
 557
 558   _dbus_assert (connection_data_slot >= 0);
 559
 560   if (!dbus_connection_set_data (connection,
 561                                  connection_data_slot,
 562                                  d, free_connection_data))
 563     {
 564       dbus_free (d);
 565       return FALSE;
 566     }
 567
 568   dbus_connection_set_route_peer_messages (connection, TRUE);
 569
 570   retval = FALSE;
 571
 572   dbus_error_init (&error);
 573   d->selinux_id = bus_selinux_init_connection_id (connection,
 574                                                   &error);
 575   if (dbus_error_is_set (&error))
 576     {
 577       /* This is a bit bogus because we pretend all errors
 578        * are OOM; this is done because we know that in bus.c
 579        * an OOM error disconnects the connection, which is
 580        * the same thing we want on any other error.
 581        */
 582       dbus_error_free (&error);
 583       goto out;
 584     }
 585
 586   if (!dbus_connection_set_watch_functions (connection,
 587                                             add_connection_watch,
 588                                             remove_connection_watch,
 589                                             NULL,
 590                                             connection,
 591                                             NULL))
 592     goto out;
 593
 594   if (!dbus_connection_set_timeout_functions (connection,
 595                                               add_connection_timeout,
 596                                               remove_connection_timeout,
 597                                               NULL,
 598                                               connection, NULL))
 599     goto out;
 600
 601   dbus_connection_set_unix_user_function (connection,
 602                                           allow_user_function,
 603                                           NULL, NULL);
 604
 605   dbus_connection_set_dispatch_status_function (connection,
 606                                                 dispatch_status_function,
 607                                                 bus_context_get_loop (connections->context),
 608                                                 NULL);
 609
 610   d->link_in_connection_list = _dbus_list_alloc_link (connection);
 611   if (d->link_in_connection_list == NULL)
 612     goto out;
 613
 614   /* Setup the connection with the dispatcher */
 615   if (!bus_dispatch_add_connection (connection))
 616     goto out;
 617
 618   if (dbus_connection_get_dispatch_status (connection) != DBUS_DISPATCH_COMPLETE)
 619     {
 620       if (!_dbus_loop_queue_dispatch (bus_context_get_loop (connections->context), connection))
 621         {
 622           bus_dispatch_remove_connection (connection);
 623           goto out;
 624         }
 625     }
 626
 627   _dbus_list_append_link (&connections->incomplete, d->link_in_connection_list);
 628   connections->n_incomplete += 1;
 629
 630   dbus_connection_ref (connection);
 631
 632   /* Note that we might disconnect ourselves here, but it only takes
 633    * effect on return to the main loop. We call this to free up
 634    * expired connections if possible, and to queue the timeout for our
 635    * own expiration.
 636    */
 637   bus_connections_expire_incomplete (connections);
 638
 639   /* And we might also disconnect ourselves here, but again it
 640    * only takes effect on return to main loop.
 641    */
 642   if (connections->n_incomplete >
 643       bus_context_get_max_incomplete_connections (connections->context))
 644     {
 645       _dbus_verbose ("Number of incomplete connections exceeds max, dropping oldest one\n");
 646
 647       _dbus_assert (connections->incomplete != NULL);
 648       /* Disconnect the oldest unauthenticated connection.  FIXME
 649        * would it be more secure to drop a *random* connection?  This
 650        * algorithm seems to mean that if someone can create new
 651        * connections quickly enough, they can keep anyone else from
 652        * completing authentication. But random may or may not really
 653        * help with that, a more elaborate solution might be required.
 654        */
 655       dbus_connection_close (connections->incomplete->data);
 656     }
 657
 658   retval = TRUE;
 659
 660  out:
 661   if (!retval)
 662     {
 663       if (d->selinux_id)
 664         bus_selinux_id_unref (d->selinux_id);
 665       d->selinux_id = NULL;
 666
 667       if (!dbus_connection_set_watch_functions (connection,
 668                                                 NULL, NULL, NULL,
 669                                                 connection,
 670                                                 NULL))
 671         _dbus_assert_not_reached ("setting watch functions to NULL failed");
 672
 673       if (!dbus_connection_set_timeout_functions (connection,
 674                                                   NULL, NULL, NULL,
 675                                                   connection,
 676                                                   NULL))
 677         _dbus_assert_not_reached ("setting timeout functions to NULL failed");
 678
 679       dbus_connection_set_unix_user_function (connection,
 680                                               NULL, NULL, NULL);
 681
 682       dbus_connection_set_dispatch_status_function (connection,
 683                                                     NULL, NULL, NULL);
 684
 685       if (d->link_in_connection_list != NULL)
 686         {
 687           _dbus_assert (d->link_in_connection_list->next == NULL);
 688           _dbus_assert (d->link_in_connection_list->prev == NULL);
 689           _dbus_list_free_link (d->link_in_connection_list);
 690           d->link_in_connection_list = NULL;
 691         }
 692
 693       if (!dbus_connection_set_data (connection,
 694                                      connection_data_slot,
 695                                      NULL, NULL))
 696         _dbus_assert_not_reached ("failed to set connection data to null");
 697
 698       /* "d" has now been freed */
 699     }
 700
 701   return retval;
 702 }
 703
 704 void
 705 bus_connections_expire_incomplete (BusConnections *connections)
 706 {
 707   int next_interval;
 708
 709   next_interval = -1;
 710
 711   if (connections->incomplete != NULL)
 712     {
 713       long tv_sec, tv_usec;
 714       DBusList *link;
 715       int auth_timeout;
 716
 717       _dbus_get_current_time (&tv_sec, &tv_usec);
 718       auth_timeout = bus_context_get_auth_timeout (connections->context);
 719
 720       link = _dbus_list_get_first_link (&connections->incomplete);
 721       while (link != NULL)
 722         {
 723           DBusList *next = _dbus_list_get_next_link (&connections->incomplete, link);
 724           DBusConnection *connection;
 725           BusConnectionData *d;
 726           double elapsed;
 727
 728           connection = link->data;
 729
 730           d = BUS_CONNECTION_DATA (connection);
 731
 732           _dbus_assert (d != NULL);
 733
 734           elapsed = ELAPSED_MILLISECONDS_SINCE (d->connection_tv_sec,
 735                                                 d->connection_tv_usec,
 736                                                 tv_sec, tv_usec);
 737
 738           if (elapsed >= (double) auth_timeout)
 739             {
 740               _dbus_verbose ("Timing out authentication for connection %p\n", connection);
 741               dbus_connection_close (connection);
 742             }
 743           else
 744             {
 745               /* We can end the loop, since the connections are in oldest-first order */
 746               next_interval = ((double)auth_timeout) - elapsed;
 747               _dbus_verbose ("Connection %p authentication expires in %d milliseconds\n",
 748                              connection, next_interval);
 749
 750               break;
 751             }
 752
 753           link = next;
 754         }
 755     }
 756
 757   bus_expire_timeout_set_interval (connections->expire_timeout,
 758                                    next_interval);
 759 }
 760
 761 static dbus_bool_t
 762 expire_incomplete_timeout (void *data)
 763 {
 764   BusConnections *connections = data;
 765
 766   _dbus_verbose ("Running %s\n", _DBUS_FUNCTION_NAME);
 767
 768   /* note that this may remove the timeout */
 769   bus_connections_expire_incomplete (connections);
 770
 771   return TRUE;
 772 }
 773
 774 dbus_bool_t
 775 bus_connection_get_groups  (DBusConnection   *connection,
 776                             unsigned long   **groups,
 777                             int              *n_groups,
 778                             DBusError        *error)
 779 {
 780   BusConnectionData *d;
 781   unsigned long uid;
 782
 783   d = BUS_CONNECTION_DATA (connection);
 784
 785   _dbus_assert (d != NULL);
 786
 787   *groups = NULL;
 788   *n_groups = 0;
 789
 790   if (dbus_connection_get_unix_user (connection, &uid))
 791     {
 792       if (!_dbus_groups_from_uid (uid, groups, n_groups))
 793         {
 794           _dbus_verbose ("Did not get any groups for UID %lu\n",
 795                          uid);
 796           return FALSE;
 797         }
 798       else
 799         {
 800           _dbus_verbose ("Got %d groups for UID %lu\n",
 801                          *n_groups, uid);
 802           return TRUE;
 803         }
 804     }
 805   else
 806     return TRUE; /* successfully got 0 groups */
 807 }
 808
 809 dbus_bool_t
 810 bus_connection_is_in_group (DBusConnection *connection,
 811                             unsigned long   gid)
 812 {
 813   int i;
 814   unsigned long *group_ids;
 815   int n_group_ids;
 816
 817   if (!bus_connection_get_groups (connection, &group_ids, &n_group_ids,
 818                                   NULL))
 819     return FALSE;
 820
 821   i = 0;
 822   while (i < n_group_ids)
 823     {
 824       if (group_ids[i] == gid)
 825         {
 826           dbus_free (group_ids);
 827           return TRUE;
 828         }
 829       ++i;
 830     }
 831
 832   dbus_free (group_ids);
 833   return FALSE;
 834 }
 835
 836 BusClientPolicy*
 837 bus_connection_get_policy (DBusConnection *connection)
 838 {
 839   BusConnectionData *d;
 840
 841   d = BUS_CONNECTION_DATA (connection);
 842
 843   _dbus_assert (d != NULL);
 844   _dbus_assert (d->policy != NULL);
 845
 846   return d->policy;
 847 }
 848
 849 static dbus_bool_t
 850 foreach_active (BusConnections               *connections,
 851                 BusConnectionForeachFunction  function,
 852                 void                         *data)
 853 {
 854   DBusList *link;
 855
 856   link = _dbus_list_get_first_link (&connections->completed);
 857   while (link != NULL)
 858     {
 859       DBusConnection *connection = link->data;
 860       DBusList *next = _dbus_list_get_next_link (&connections->completed, link);
 861
 862       if (!(* function) (connection, data))
 863         return FALSE;
 864
 865       link = next;
 866     }
 867
 868   return TRUE;
 869 }
 870
 871 static dbus_bool_t
 872 foreach_inactive (BusConnections               *connections,
 873                   BusConnectionForeachFunction  function,
 874                   void                         *data)
 875 {
 876   DBusList *link;
 877
 878   link = _dbus_list_get_first_link (&connections->incomplete);
 879   while (link != NULL)
 880     {
 881       DBusConnection *connection = link->data;
 882       DBusList *next = _dbus_list_get_next_link (&connections->incomplete, link);
 883
 884       if (!(* function) (connection, data))
 885         return FALSE;
 886
 887       link = next;
 888     }
 889
 890   return TRUE;
 891 }
 892
 893 /**
 894  * Calls function on each active connection; if the function returns
 895  * #FALSE, stops iterating. Active connections are authenticated
 896  * and have sent a Hello message.
 897  *
 898  * @param connections the connections object
 899  * @param function the function
 900  * @param data data to pass to it as a second arg
 901  */
 902 void
 903 bus_connections_foreach_active (BusConnections               *connections,
 904                                 BusConnectionForeachFunction  function,
 905                                 void                         *data)
 906 {
 907   foreach_active (connections, function, data);
 908 }
 909
 910 /**
 911  * Calls function on each connection; if the function returns
 912  * #FALSE, stops iterating.
 913  *
 914  * @param connections the connections object
 915  * @param function the function
 916  * @param data data to pass to it as a second arg
 917  */
 918 void
 919 bus_connections_foreach (BusConnections               *connections,
 920                          BusConnectionForeachFunction  function,
 921                          void                         *data)
 922 {
 923   if (!foreach_active (connections, function, data))
 924     return;
 925
 926   foreach_inactive (connections, function, data);
 927 }
 928
 929 BusContext*
 930 bus_connections_get_context (BusConnections *connections)
 931 {
 932   return connections->context;
 933 }
 934
 935 /*
 936  * This is used to avoid covering the same connection twice when
 937  * traversing connections. Note that it assumes we will
 938  * bus_connection_mark_stamp() each connection at least once per
 939  * INT_MAX increments of the global stamp, or wraparound would break
 940  * things.
 941  */
 942 void
 943 bus_connections_increment_stamp (BusConnections *connections)
 944 {
 945   connections->stamp += 1;
 946 }
 947
 948 /* Mark connection with current stamp, return TRUE if it
 949  * didn't already have that stamp
 950  */
 951 dbus_bool_t
 952 bus_connection_mark_stamp (DBusConnection *connection)
 953 {
 954   BusConnectionData *d;
 955
 956   d = BUS_CONNECTION_DATA (connection);
 957
 958   _dbus_assert (d != NULL);
 959
 960   if (d->stamp == d->connections->stamp)
 961     return FALSE;
 962   else
 963     {
 964       d->stamp = d->connections->stamp;
 965       return TRUE;
 966     }
 967 }
 968
 969 BusContext*
 970 bus_connection_get_context (DBusConnection *connection)
 971 {
 972   BusConnectionData *d;
 973
 974   d = BUS_CONNECTION_DATA (connection);
 975
 976   _dbus_assert (d != NULL);
 977
 978   return d->connections->context;
 979 }
 980
 981 BusConnections*
 982 bus_connection_get_connections (DBusConnection *connection)
 983 {
 984   BusConnectionData *d;
 985
 986   d = BUS_CONNECTION_DATA (connection);
 987
 988   _dbus_assert (d != NULL);
 989
 990   return d->connections;
 991 }
 992
 993 BusRegistry*
 994 bus_connection_get_registry (DBusConnection *connection)
 995 {
 996   BusConnectionData *d;
 997
 998   d = BUS_CONNECTION_DATA (connection);
 999
1000   _dbus_assert (d != NULL);
1001
1002   return bus_context_get_registry (d->connections->context);
1003 }
1004
1005 BusActivation*
1006 bus_connection_get_activation (DBusConnection *connection)
1007 {
1008   BusConnectionData *d;
1009
1010   d = BUS_CONNECTION_DATA (connection);
1011
1012   _dbus_assert (d != NULL);
1013
1014   return bus_context_get_activation (d->connections->context);
1015 }
1016
1017 BusMatchmaker*
1018 bus_connection_get_matchmaker (DBusConnection *connection)
1019 {
1020   BusConnectionData *d;
1021
1022   d = BUS_CONNECTION_DATA (connection);
1023
1024   _dbus_assert (d != NULL);
1025
1026   return bus_context_get_matchmaker (d->connections->context);
1027 }
1028
1029 BusSELinuxID*
1030 bus_connection_get_selinux_id (DBusConnection *connection)
1031 {
1032   BusConnectionData *d;
1033
1034   d = BUS_CONNECTION_DATA (connection);
1035
1036   _dbus_assert (d != NULL);
1037
1038   return d->selinux_id;
1039 }
1040
1041 /**
1042  * Checks whether the connection is registered with the message bus.
1043  *
1044  * @param connection the connection
1045  * @returns #TRUE if we're an active message bus participant
1046  */
1047 dbus_bool_t
1048 bus_connection_is_active (DBusConnection *connection)
1049 {
1050   BusConnectionData *d;
1051
1052   d = BUS_CONNECTION_DATA (connection);
1053
1054   return d != NULL && d->name != NULL;
1055 }
1056
1057 dbus_bool_t
1058 bus_connection_preallocate_oom_error (DBusConnection *connection)
1059 {
1060   DBusMessage *message;
1061   DBusPreallocatedSend *preallocated;
1062   BusConnectionData *d;
1063
1064   d = BUS_CONNECTION_DATA (connection);
1065
1066   _dbus_assert (d != NULL);
1067
1068   if (d->oom_preallocated != NULL)
1069     return TRUE;
1070
1071   preallocated = dbus_connection_preallocate_send (connection);
1072   if (preallocated == NULL)
1073     return FALSE;
1074
1075   message = dbus_message_new (DBUS_MESSAGE_TYPE_ERROR);
1076
1077   if (message == NULL)
1078     {
1079       dbus_connection_free_preallocated_send (connection, preallocated);
1080       return FALSE;
1081     }
1082
1083   /* d->name may be NULL, but that is OK */
1084   if (!dbus_message_set_error_name (message, DBUS_ERROR_NO_MEMORY) ||
1085       !dbus_message_set_destination (message, d->name) ||
1086       !dbus_message_set_sender (message,
1087                                 DBUS_SERVICE_DBUS))
1088     {
1089       dbus_connection_free_preallocated_send (connection, preallocated);
1090       dbus_message_unref (message);
1091       return FALSE;
1092     }
1093
1094   /* set reply serial to placeholder value just so space is already allocated
1095    * for it.
1096    */
1097   if (!dbus_message_set_reply_serial (message, 14))
1098     {
1099       dbus_connection_free_preallocated_send (connection, preallocated);
1100       dbus_message_unref (message);
1101       return FALSE;
1102     }
1103
1104   d->oom_message = message;
1105   d->oom_preallocated = preallocated;
1106
1107   return TRUE;
1108 }
1109
1110 void
1111 bus_connection_send_oom_error (DBusConnection *connection,
1112                                DBusMessage    *in_reply_to)
1113 {
1114   BusConnectionData *d;
1115
1116   d = BUS_CONNECTION_DATA (connection);
1117
1118   _dbus_assert (d != NULL);
1119   _dbus_assert (d->oom_message != NULL);
1120
1121   /* should always succeed since we set it to a placeholder earlier */
1122   if (!dbus_message_set_reply_serial (d->oom_message,
1123                                       dbus_message_get_serial (in_reply_to)))
1124     _dbus_assert_not_reached ("Failed to set reply serial for preallocated oom message");
1125
1126   _dbus_assert (dbus_message_get_sender (d->oom_message) != NULL);
1127
1128   dbus_connection_send_preallocated (connection, d->oom_preallocated,
1129                                      d->oom_message, NULL);
1130
1131   dbus_message_unref (d->oom_message);
1132   d->oom_message = NULL;
1133   d->oom_preallocated = NULL;
1134 }
1135
1136 void
1137 bus_connection_add_match_rule_link (DBusConnection *connection,
1138                                     DBusList       *link)
1139 {
1140   BusConnectionData *d;
1141
1142   d = BUS_CONNECTION_DATA (connection);
1143   _dbus_assert (d != NULL);
1144
1145   _dbus_list_append_link (&d->match_rules, link);
1146
1147   d->n_match_rules += 1;
1148 }
1149
1150 dbus_bool_t
1151 bus_connection_add_match_rule (DBusConnection *connection,
1152                                BusMatchRule   *rule)
1153 {
1154     DBusList *link;
1155
1156   link = _dbus_list_alloc_link (rule);
1157
1158   if (link == NULL)
1159     return FALSE;
1160
1161   bus_connection_add_match_rule_link (connection, link);
1162
1163   return TRUE;
1164 }
1165
1166 void
1167 bus_connection_remove_match_rule (DBusConnection *connection,
1168                                   BusMatchRule   *rule)
1169 {
1170   BusConnectionData *d;
1171
1172   d = BUS_CONNECTION_DATA (connection);
1173   _dbus_assert (d != NULL);
1174
1175   _dbus_list_remove_last (&d->match_rules, rule);
1176
1177   d->n_match_rules -= 1;
1178   _dbus_assert (d->n_match_rules >= 0);
1179 }
1180
1181 int
1182 bus_connection_get_n_match_rules (DBusConnection *connection)
1183 {
1184   BusConnectionData *d;
1185
1186   d = BUS_CONNECTION_DATA (connection);
1187   _dbus_assert (d != NULL);
1188
1189   return d->n_match_rules;
1190 }
1191
1192 void
1193 bus_connection_add_owned_service_link (DBusConnection *connection,
1194                                        DBusList       *link)
1195 {
1196   BusConnectionData *d;
1197
1198   d = BUS_CONNECTION_DATA (connection);
1199   _dbus_assert (d != NULL);
1200
1201   _dbus_list_append_link (&d->services_owned, link);
1202
1203   d->n_services_owned += 1;
1204 }
1205
1206 dbus_bool_t
1207 bus_connection_add_owned_service (DBusConnection *connection,
1208                                   BusService     *service)
1209 {
1210   DBusList *link;
1211
1212   link = _dbus_list_alloc_link (service);
1213
1214   if (link == NULL)
1215     return FALSE;
1216
1217   bus_connection_add_owned_service_link (connection, link);
1218
1219   return TRUE;
1220 }
1221
1222 void
1223 bus_connection_remove_owned_service (DBusConnection *connection,
1224                                      BusService     *service)
1225 {
1226   BusConnectionData *d;
1227
1228   d = BUS_CONNECTION_DATA (connection);
1229   _dbus_assert (d != NULL);
1230
1231   _dbus_list_remove_last (&d->services_owned, service);
1232
1233   d->n_services_owned -= 1;
1234   _dbus_assert (d->n_services_owned >= 0);
1235 }
1236
1237 int
1238 bus_connection_get_n_services_owned (DBusConnection *connection)
1239 {
1240   BusConnectionData *d;
1241
1242   d = BUS_CONNECTION_DATA (connection);
1243   _dbus_assert (d != NULL);
1244
1245   return d->n_services_owned;
1246 }
1247
1248 dbus_bool_t
1249 bus_connection_complete (DBusConnection   *connection,
1250                          const DBusString *name,
1251                          DBusError        *error)
1252 {
1253   BusConnectionData *d;
1254   unsigned long uid;
1255
1256   d = BUS_CONNECTION_DATA (connection);
1257   _dbus_assert (d != NULL);
1258   _dbus_assert (d->name == NULL);
1259   _dbus_assert (d->policy == NULL);
1260
1261   _dbus_assert (!bus_connection_is_active (connection));
1262
1263   if (!_dbus_string_copy_data (name, &d->name))
1264     {
1265       BUS_SET_OOM (error);
1266       return FALSE;
1267     }
1268
1269   _dbus_assert (d->name != NULL);
1270
1271   _dbus_verbose ("Name %s assigned to %p\n", d->name, connection);
1272
1273   d->policy = bus_context_create_client_policy (d->connections->context,
1274                                                 connection,
1275                                                 error);
1276
1277   /* we may have a NULL policy on OOM or error getting list of
1278    * groups for a user. In the latter case we don't handle it so
1279    * well currently, as it will just keep failing over and over.
1280    */
1281
1282   if (d->policy == NULL)
1283     {
1284       _dbus_verbose ("Failed to create security policy for connection %p\n",
1285                      connection);
1286       _DBUS_ASSERT_ERROR_IS_SET (error);
1287       dbus_free (d->name);
1288       d->name = NULL;
1289       return FALSE;
1290     }
1291
1292   if (dbus_connection_get_unix_user (connection, &uid))
1293     {
1294       if (!adjust_connections_for_uid (d->connections,
1295                                        uid, 1))
1296         {
1297           BUS_SET_OOM (error);
1298           dbus_free (d->name);
1299           d->name = NULL;
1300           return FALSE;
1301         }
1302     }
1303
1304   /* Now the connection is active, move it between lists */
1305   _dbus_list_unlink (&d->connections->incomplete,
1306                      d->link_in_connection_list);
1307   d->connections->n_incomplete -= 1;
1308   _dbus_list_append_link (&d->connections->completed,
1309                           d->link_in_connection_list);
1310   d->connections->n_completed += 1;
1311
1312   _dbus_assert (d->connections->n_incomplete >= 0);
1313   _dbus_assert (d->connections->n_completed > 0);
1314
1315   /* See if we can remove the timeout */
1316   bus_connections_expire_incomplete (d->connections);
1317
1318   _dbus_assert (bus_connection_is_active (connection));
1319
1320   return TRUE;
1321 }
1322
1323 const char *
1324 bus_connection_get_name (DBusConnection *connection)
1325 {
1326   BusConnectionData *d;
1327
1328   d = BUS_CONNECTION_DATA (connection);
1329   _dbus_assert (d != NULL);
1330
1331   return d->name;
1332 }
1333
1334 /**
1335  * Check whether completing the passed-in connection would
1336  * exceed limits, and if so set error and return #FALSE
1337  */
1338 dbus_bool_t
1339 bus_connections_check_limits (BusConnections  *connections,
1340                               DBusConnection  *requesting_completion,
1341                               DBusError       *error)
1342 {
1343   BusConnectionData *d;
1344   unsigned long uid;
1345
1346   d = BUS_CONNECTION_DATA (requesting_completion);
1347   _dbus_assert (d != NULL);
1348
1349   _dbus_assert (d->name == NULL);
1350
1351   if (connections->n_completed >=
1352       bus_context_get_max_completed_connections (connections->context))
1353     {
1354       dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
1355                       "The maximum number of active connections has been reached");
1356       return FALSE;
1357     }
1358
1359   if (dbus_connection_get_unix_user (requesting_completion, &uid))
1360     {
1361       if (get_connections_for_uid (connections, uid) >=
1362           bus_context_get_max_connections_per_user (connections->context))
1363         {
1364           dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
1365                           "The maximum number of active connections for UID %lu has been reached",
1366                           uid);
1367           return FALSE;
1368         }
1369     }
1370
1371   return TRUE;
1372 }
1373
1374 static void
1375 bus_pending_reply_free (BusPendingReply *pending)
1376 {
1377   _dbus_verbose ("Freeing pending reply %p, replier %p receiver %p serial %u\n",
1378                  pending,
1379                  pending->will_send_reply,
1380                  pending->will_get_reply,
1381                  pending->reply_serial);
1382
1383   dbus_free (pending);
1384 }
1385
1386 static dbus_bool_t
1387 bus_pending_reply_send_no_reply (BusConnections  *connections,
1388                                  BusTransaction  *transaction,
1389                                  BusPendingReply *pending)
1390 {
1391   DBusMessage *message;
1392   DBusMessageIter iter;
1393   dbus_bool_t retval;
1394   const char *errmsg;
1395
1396   retval = FALSE;
1397
1398   message = dbus_message_new (DBUS_MESSAGE_TYPE_ERROR);
1399   if (message == NULL)
1400     return FALSE;
1401
1402   dbus_message_set_no_reply (message, TRUE);
1403
1404   if (!dbus_message_set_reply_serial (message,
1405                                       pending->reply_serial))
1406     goto out;
1407
1408   if (!dbus_message_set_error_name (message,
1409                                     DBUS_ERROR_NO_REPLY))
1410     goto out;
1411
1412   errmsg = "Message did not receive a reply (timeout by message bus)";
1413   dbus_message_iter_init_append (message, &iter);
1414   if (!dbus_message_iter_append_basic (&iter, DBUS_TYPE_STRING, &errmsg))
1415     goto out;
1416
1417   if (!bus_transaction_send_from_driver (transaction, pending->will_get_reply,
1418                                          message))
1419     goto out;
1420
1421   retval = TRUE;
1422
1423  out:
1424   dbus_message_unref (message);
1425   return retval;
1426 }
1427
1428 static dbus_bool_t
1429 bus_pending_reply_expired (BusExpireList *list,
1430                            DBusList      *link,
1431                            void          *data)
1432 {
1433   BusPendingReply *pending = link->data;
1434   BusConnections *connections = data;
1435   BusTransaction *transaction;
1436
1437   /* No reply is forthcoming. So nuke it if we can. If not,
1438    * leave it in the list to try expiring again later when we
1439    * get more memory.
1440    */
1441
1442   _dbus_verbose ("Expiring pending reply %p, replier %p receiver %p serial %u\n",
1443                  pending,
1444                  pending->will_send_reply,
1445                  pending->will_get_reply,
1446                  pending->reply_serial);
1447
1448   transaction = bus_transaction_new (connections->context);
1449   if (transaction == NULL)
1450     return FALSE;
1451
1452   if (!bus_pending_reply_send_no_reply (connections,
1453                                         transaction,
1454                                         pending))
1455     {
1456       bus_transaction_cancel_and_free (transaction);
1457       return FALSE;
1458     }
1459
1460   _dbus_list_remove_link (&connections->pending_replies->items,
1461                           link);
1462   bus_pending_reply_free (pending);
1463   bus_transaction_execute_and_free (transaction);
1464
1465   return TRUE;
1466 }
1467
1468 static void
1469 bus_connection_drop_pending_replies (BusConnections  *connections,
1470                                      DBusConnection  *connection)
1471 {
1472   /* The DBusConnection is almost 100% finalized here, so you can't
1473    * do anything with it except check for pointer equality
1474    */
1475   DBusList *link;
1476
1477   _dbus_verbose ("Dropping pending replies that involve connection %p\n",
1478                  connection);
1479
1480   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1481   while (link != NULL)
1482     {
1483       DBusList *next;
1484       BusPendingReply *pending;
1485
1486       next = _dbus_list_get_next_link (&connections->pending_replies->items,
1487                                        link);
1488       pending = link->data;
1489
1490       if (pending->will_get_reply == connection)
1491         {
1492           /* We don't need to track this pending reply anymore */
1493
1494           _dbus_verbose ("Dropping pending reply %p, replier %p receiver %p serial %u\n",
1495                          pending,
1496                          pending->will_send_reply,
1497                          pending->will_get_reply,
1498                          pending->reply_serial);
1499
1500           _dbus_list_remove_link (&connections->pending_replies->items,
1501                                   link);
1502           bus_pending_reply_free (pending);
1503         }
1504       else if (pending->will_send_reply == connection)
1505         {
1506           /* The reply isn't going to be sent, so set things
1507            * up so it will be expired right away
1508            */
1509           _dbus_verbose ("Will expire pending reply %p, replier %p receiver %p serial %u\n",
1510                          pending,
1511                          pending->will_send_reply,
1512                          pending->will_get_reply,
1513                          pending->reply_serial);
1514
1515           pending->will_send_reply = NULL;
1516           pending->expire_item.added_tv_sec = 0;
1517           pending->expire_item.added_tv_usec = 0;
1518
1519           bus_expire_timeout_set_interval (connections->pending_replies->timeout,
1520                                            0);
1521         }
1522
1523       link = next;
1524     }
1525 }
1526
1527
1528 typedef struct
1529 {
1530   BusPendingReply *pending;
1531   BusConnections  *connections;
1532 } CancelPendingReplyData;
1533
1534 static void
1535 cancel_pending_reply (void *data)
1536 {
1537   CancelPendingReplyData *d = data;
1538
1539   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1540
1541   if (!_dbus_list_remove (&d->connections->pending_replies->items,
1542                           d->pending))
1543     _dbus_assert_not_reached ("pending reply did not exist to be cancelled");
1544
1545   bus_pending_reply_free (d->pending); /* since it's been cancelled */
1546 }
1547
1548 static void
1549 cancel_pending_reply_data_free (void *data)
1550 {
1551   CancelPendingReplyData *d = data;
1552
1553   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1554
1555   /* d->pending should be either freed or still
1556    * in the list of pending replies (owned by someone
1557    * else)
1558    */
1559
1560   dbus_free (d);
1561 }
1562
1563 /*
1564  * Record that a reply is allowed; return TRUE on success.
1565  */
1566 dbus_bool_t
1567 bus_connections_expect_reply (BusConnections  *connections,
1568                               BusTransaction  *transaction,
1569                               DBusConnection  *will_get_reply,
1570                               DBusConnection  *will_send_reply,
1571                               DBusMessage     *reply_to_this,
1572                               DBusError       *error)
1573 {
1574   BusPendingReply *pending;
1575   dbus_uint32_t reply_serial;
1576   DBusList *link;
1577   CancelPendingReplyData *cprd;
1578   int count;
1579
1580   _dbus_assert (will_get_reply != NULL);
1581   _dbus_assert (will_send_reply != NULL);
1582   _dbus_assert (reply_to_this != NULL);
1583
1584   if (dbus_message_get_no_reply (reply_to_this))
1585     return TRUE; /* we won't allow a reply, since client doesn't care for one. */
1586
1587   reply_serial = dbus_message_get_serial (reply_to_this);
1588
1589   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1590   count = 0;
1591   while (link != NULL)
1592     {
1593       pending = link->data;
1594
1595       if (pending->reply_serial == reply_serial &&
1596           pending->will_get_reply == will_get_reply &&
1597           pending->will_send_reply == will_send_reply)
1598         {
1599           dbus_set_error (error, DBUS_ERROR_ACCESS_DENIED,
1600                           "Message has the same reply serial as a currently-outstanding existing method call");
1601           return FALSE;
1602         }
1603
1604       link = _dbus_list_get_next_link (&connections->pending_replies->items,
1605                                        link);
1606       if (pending->will_get_reply == will_get_reply)
1607         ++count;
1608     }
1609
1610   if (count >=
1611       bus_context_get_max_replies_per_connection (connections->context))
1612     {
1613       dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
1614                       "The maximum number of pending replies per connection has been reached");
1615       return FALSE;
1616     }
1617
1618   pending = dbus_new0 (BusPendingReply, 1);
1619   if (pending == NULL)
1620     {
1621       BUS_SET_OOM (error);
1622       return FALSE;
1623     }
1624
1625 #ifdef DBUS_ENABLE_VERBOSE_MODE
1626   /* so we can see a not-yet-added pending reply */
1627   pending->expire_item.added_tv_sec = 1;
1628   pending->expire_item.added_tv_usec = 1;
1629 #endif
1630
1631   pending->will_get_reply = will_get_reply;
1632   pending->will_send_reply = will_send_reply;
1633   pending->reply_serial = reply_serial;
1634
1635   cprd = dbus_new0 (CancelPendingReplyData, 1);
1636   if (cprd == NULL)
1637     {
1638       BUS_SET_OOM (error);
1639       bus_pending_reply_free (pending);
1640       return FALSE;
1641     }
1642
1643   if (!_dbus_list_prepend (&connections->pending_replies->items,
1644                            pending))
1645     {
1646       BUS_SET_OOM (error);
1647       dbus_free (cprd);
1648       bus_pending_reply_free (pending);
1649       return FALSE;
1650     }
1651
1652   if (!bus_transaction_add_cancel_hook (transaction,
1653                                         cancel_pending_reply,
1654                                         cprd,
1655                                         cancel_pending_reply_data_free))
1656     {
1657       BUS_SET_OOM (error);
1658       _dbus_list_remove (&connections->pending_replies->items, pending);
1659       dbus_free (cprd);
1660       bus_pending_reply_free (pending);
1661       return FALSE;
1662     }
1663
1664   cprd->pending = pending;
1665   cprd->connections = connections;
1666
1667   _dbus_get_current_time (&pending->expire_item.added_tv_sec,
1668                           &pending->expire_item.added_tv_usec);
1669
1670   _dbus_verbose ("Added pending reply %p, replier %p receiver %p serial %u\n",
1671                  pending,
1672                  pending->will_send_reply,
1673                  pending->will_get_reply,
1674                  pending->reply_serial);
1675
1676   return TRUE;
1677 }
1678
1679 typedef struct
1680 {
1681   DBusList        *link;
1682   BusConnections  *connections;
1683 } CheckPendingReplyData;
1684
1685 static void
1686 cancel_check_pending_reply (void *data)
1687 {
1688   CheckPendingReplyData *d = data;
1689
1690   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1691
1692   _dbus_list_prepend_link (&d->connections->pending_replies->items,
1693                            d->link);
1694   d->link = NULL;
1695 }
1696
1697 static void
1698 check_pending_reply_data_free (void *data)
1699 {
1700   CheckPendingReplyData *d = data;
1701
1702   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1703
1704   if (d->link != NULL)
1705     {
1706       BusPendingReply *pending = d->link->data;
1707
1708       _dbus_assert (_dbus_list_find_last (&d->connections->pending_replies->items,
1709                                           pending) == NULL);
1710
1711       bus_pending_reply_free (pending);
1712       _dbus_list_free_link (d->link);
1713     }
1714
1715   dbus_free (d);
1716 }
1717
1718 /*
1719  * Check whether a reply is allowed, remove BusPendingReply
1720  * if so, return TRUE if so.
1721  */
1722 dbus_bool_t
1723 bus_connections_check_reply (BusConnections *connections,
1724                              BusTransaction *transaction,
1725                              DBusConnection *sending_reply,
1726                              DBusConnection *receiving_reply,
1727                              DBusMessage    *reply,
1728                              DBusError      *error)
1729 {
1730   CheckPendingReplyData *cprd;
1731   DBusList *link;
1732   dbus_uint32_t reply_serial;
1733
1734   _dbus_assert (sending_reply != NULL);
1735   _dbus_assert (receiving_reply != NULL);
1736
1737   reply_serial = dbus_message_get_reply_serial (reply);
1738
1739   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1740   while (link != NULL)
1741     {
1742       BusPendingReply *pending = link->data;
1743
1744       if (pending->reply_serial == reply_serial &&
1745           pending->will_get_reply == receiving_reply &&
1746           pending->will_send_reply == sending_reply)
1747         {
1748           _dbus_verbose ("Found pending reply with serial %u\n", reply_serial);
1749           break;
1750         }
1751
1752       link = _dbus_list_get_next_link (&connections->pending_replies->items,
1753                                        link);
1754     }
1755
1756   if (link == NULL)
1757     {
1758       _dbus_verbose ("No pending reply expected\n");
1759
1760       return FALSE;
1761     }
1762
1763   cprd = dbus_new0 (CheckPendingReplyData, 1);
1764   if (cprd == NULL)
1765     {
1766       BUS_SET_OOM (error);
1767       return FALSE;
1768     }
1769
1770   if (!bus_transaction_add_cancel_hook (transaction,
1771                                         cancel_check_pending_reply,
1772                                         cprd,
1773                                         check_pending_reply_data_free))
1774     {
1775       BUS_SET_OOM (error);
1776       dbus_free (cprd);
1777       return FALSE;
1778     }
1779
1780   cprd->link = link;
1781   cprd->connections = connections;
1782
1783   _dbus_list_unlink (&connections->pending_replies->items,
1784                      link);
1785
1786   _dbus_assert (_dbus_list_find_last (&connections->pending_replies->items,
1787                                       link->data) == NULL);
1788
1789   return TRUE;
1790 }
1791
1792 /*
1793  * Transactions
1794  *
1795  * Note that this is fairly fragile; in particular, don't try to use
1796  * one transaction across any main loop iterations.
1797  */
1798
1799 typedef struct
1800 {
1801   BusTransaction *transaction;
1802   DBusMessage    *message;
1803   DBusPreallocatedSend *preallocated;
1804 } MessageToSend;
1805
1806 typedef struct
1807 {
1808   BusTransactionCancelFunction cancel_function;
1809   DBusFreeFunction free_data_function;
1810   void *data;
1811 } CancelHook;
1812
1813 struct BusTransaction
1814 {
1815   DBusList *connections;
1816   BusContext *context;
1817   DBusList *cancel_hooks;
1818 };
1819
1820 static void
1821 message_to_send_free (DBusConnection *connection,
1822                       MessageToSend  *to_send)
1823 {
1824   if (to_send->message)
1825     dbus_message_unref (to_send->message);
1826
1827   if (to_send->preallocated)
1828     dbus_connection_free_preallocated_send (connection, to_send->preallocated);
1829
1830   dbus_free (to_send);
1831 }
1832
1833 static void
1834 cancel_hook_cancel (void *element,
1835                     void *data)
1836 {
1837   CancelHook *ch = element;
1838
1839   _dbus_verbose ("Running transaction cancel hook\n");
1840
1841   if (ch->cancel_function)
1842     (* ch->cancel_function) (ch->data);
1843 }
1844
1845 static void
1846 cancel_hook_free (void *element,
1847                   void *data)
1848 {
1849   CancelHook *ch = element;
1850
1851   if (ch->free_data_function)
1852     (* ch->free_data_function) (ch->data);
1853
1854   dbus_free (ch);
1855 }
1856
1857 static void
1858 free_cancel_hooks (BusTransaction *transaction)
1859 {
1860   _dbus_list_foreach (&transaction->cancel_hooks,
1861                       cancel_hook_free, NULL);
1862
1863   _dbus_list_clear (&transaction->cancel_hooks);
1864 }
1865
1866 BusTransaction*
1867 bus_transaction_new (BusContext *context)
1868 {
1869   BusTransaction *transaction;
1870
1871   transaction = dbus_new0 (BusTransaction, 1);
1872   if (transaction == NULL)
1873     return NULL;
1874
1875   transaction->context = context;
1876
1877   return transaction;
1878 }
1879
1880 BusContext*
1881 bus_transaction_get_context (BusTransaction  *transaction)
1882 {
1883   return transaction->context;
1884 }
1885
1886 BusConnections*
1887 bus_transaction_get_connections (BusTransaction  *transaction)
1888 {
1889   return bus_context_get_connections (transaction->context);
1890 }
1891
1892 dbus_bool_t
1893 bus_transaction_send_from_driver (BusTransaction *transaction,
1894                                   DBusConnection *connection,
1895                                   DBusMessage    *message)
1896 {
1897   /* We have to set the sender to the driver, and have
1898    * to check security policy since it was not done in
1899    * dispatch.c
1900    */
1901   _dbus_verbose ("Sending %s %s %s from driver\n",
1902                  dbus_message_get_interface (message) ?
1903                  dbus_message_get_interface (message) : "(no interface)",
1904                  dbus_message_get_member (message) ?
1905                  dbus_message_get_member (message) : "(no member)",
1906                  dbus_message_get_error_name (message) ?
1907                  dbus_message_get_error_name (message) : "(no error name)");
1908
1909   if (!dbus_message_set_sender (message, DBUS_SERVICE_DBUS))
1910     return FALSE;
1911
1912   if (bus_connection_is_active (connection))
1913     {
1914       if (!dbus_message_set_destination (message,
1915                                          bus_connection_get_name (connection)))
1916         return FALSE;
1917     }
1918
1919   /* bus driver never wants a reply */
1920   dbus_message_set_no_reply (message, TRUE);
1921
1922   /* If security policy doesn't allow the message, we silently
1923    * eat it; the driver doesn't care about getting a reply.
1924    */
1925   if (!bus_context_check_security_policy (bus_transaction_get_context (transaction),
1926                                           transaction,
1927                                           NULL, connection, connection, message, NULL))
1928     return TRUE;
1929
1930   return bus_transaction_send (transaction, connection, message);
1931 }
1932
1933 dbus_bool_t
1934 bus_transaction_send (BusTransaction *transaction,
1935                       DBusConnection *connection,
1936                       DBusMessage    *message)
1937 {
1938   MessageToSend *to_send;
1939   BusConnectionData *d;
1940   DBusList *link;
1941
1942   _dbus_verbose ("  trying to add %s interface=%s member=%s error=%s to transaction%s\n",
1943                  dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_ERROR ? "error" :
1944                  dbus_message_get_reply_serial (message) != 0 ? "reply" :
1945                  "message",
1946                  dbus_message_get_interface (message) ?
1947                  dbus_message_get_interface (message) : "(unset)",
1948                  dbus_message_get_member (message) ?
1949                  dbus_message_get_member (message) : "(unset)",
1950                  dbus_message_get_error_name (message) ?
1951                  dbus_message_get_error_name (message) : "(unset)",
1952                  dbus_connection_get_is_connected (connection) ?
1953                  "" : " (disconnected)");
1954
1955   _dbus_assert (dbus_message_get_sender (message) != NULL);
1956
1957   if (!dbus_connection_get_is_connected (connection))
1958     return TRUE; /* silently ignore disconnected connections */
1959
1960   d = BUS_CONNECTION_DATA (connection);
1961   _dbus_assert (d != NULL);
1962
1963   to_send = dbus_new (MessageToSend, 1);
1964   if (to_send == NULL)
1965     {
1966       return FALSE;
1967     }
1968
1969   to_send->preallocated = dbus_connection_preallocate_send (connection);
1970   if (to_send->preallocated == NULL)
1971     {
1972       dbus_free (to_send);
1973       return FALSE;
1974     }
1975
1976   dbus_message_ref (message);
1977   to_send->message = message;
1978   to_send->transaction = transaction;
1979
1980   _dbus_verbose ("about to prepend message\n");
1981
1982   if (!_dbus_list_prepend (&d->transaction_messages, to_send))
1983     {
1984       message_to_send_free (connection, to_send);
1985       return FALSE;
1986     }
1987
1988   _dbus_verbose ("prepended message\n");
1989
1990   /* See if we already had this connection in the list
1991    * for this transaction. If we have a pending message,
1992    * then we should already be in transaction->connections
1993    */
1994   link = _dbus_list_get_first_link (&d->transaction_messages);
1995   _dbus_assert (link->data == to_send);
1996   link = _dbus_list_get_next_link (&d->transaction_messages, link);
1997   while (link != NULL)
1998     {
1999       MessageToSend *m = link->data;
2000       DBusList *next = _dbus_list_get_next_link (&d->transaction_messages, link);
2001
2002       if (m->transaction == transaction)
2003         break;
2004
2005       link = next;
2006     }
2007
2008   if (link == NULL)
2009     {
2010       if (!_dbus_list_prepend (&transaction->connections, connection))
2011         {
2012           _dbus_list_remove (&d->transaction_messages, to_send);
2013           message_to_send_free (connection, to_send);
2014           return FALSE;
2015         }
2016     }
2017
2018   return TRUE;
2019 }
2020
2021 static void
2022 connection_cancel_transaction (DBusConnection *connection,
2023                                BusTransaction *transaction)
2024 {
2025   DBusList *link;
2026   BusConnectionData *d;
2027
2028   d = BUS_CONNECTION_DATA (connection);
2029   _dbus_assert (d != NULL);
2030
2031   link = _dbus_list_get_first_link (&d->transaction_messages);
2032   while (link != NULL)
2033     {
2034       MessageToSend *m = link->data;
2035       DBusList *next = _dbus_list_get_next_link (&d->transaction_messages, link);
2036
2037       if (m->transaction == transaction)
2038         {
2039           _dbus_list_remove_link (&d->transaction_messages,
2040                                   link);
2041
2042           message_to_send_free (connection, m);
2043         }
2044
2045       link = next;
2046     }
2047 }
2048
2049 void
2050 bus_transaction_cancel_and_free (BusTransaction *transaction)
2051 {
2052   DBusConnection *connection;
2053
2054   _dbus_verbose ("TRANSACTION: cancelled\n");
2055
2056   while ((connection = _dbus_list_pop_first (&transaction->connections)))
2057     connection_cancel_transaction (connection, transaction);
2058
2059   _dbus_assert (transaction->connections == NULL);
2060
2061   _dbus_list_foreach (&transaction->cancel_hooks,
2062                       cancel_hook_cancel, NULL);
2063
2064   free_cancel_hooks (transaction);
2065
2066   dbus_free (transaction);
2067 }
2068
2069 static void
2070 connection_execute_transaction (DBusConnection *connection,
2071                                 BusTransaction *transaction)
2072 {
2073   DBusList *link;
2074   BusConnectionData *d;
2075
2076   d = BUS_CONNECTION_DATA (connection);
2077   _dbus_assert (d != NULL);
2078
2079   /* Send the queue in order (FIFO) */
2080   link = _dbus_list_get_last_link (&d->transaction_messages);
2081   while (link != NULL)
2082     {
2083       MessageToSend *m = link->data;
2084       DBusList *prev = _dbus_list_get_prev_link (&d->transaction_messages, link);
2085
2086       if (m->transaction == transaction)
2087         {
2088           _dbus_list_remove_link (&d->transaction_messages,
2089                                   link);
2090
2091           _dbus_assert (dbus_message_get_sender (m->message) != NULL);
2092
2093           dbus_connection_send_preallocated (connection,
2094                                              m->preallocated,
2095                                              m->message,
2096                                              NULL);
2097
2098           m->preallocated = NULL; /* so we don't double-free it */
2099
2100           message_to_send_free (connection, m);
2101         }
2102
2103       link = prev;
2104     }
2105 }
2106
2107 void
2108 bus_transaction_execute_and_free (BusTransaction *transaction)
2109 {
2110   /* For each connection in transaction->connections
2111    * send the messages
2112    */
2113   DBusConnection *connection;
2114
2115   _dbus_verbose ("TRANSACTION: executing\n");
2116
2117   while ((connection = _dbus_list_pop_first (&transaction->connections)))
2118     connection_execute_transaction (connection, transaction);
2119
2120   _dbus_assert (transaction->connections == NULL);
2121
2122   free_cancel_hooks (transaction);
2123
2124   dbus_free (transaction);
2125 }
2126
2127 static void
2128 bus_connection_remove_transactions (DBusConnection *connection)
2129 {
2130   MessageToSend *to_send;
2131   BusConnectionData *d;
2132
2133   d = BUS_CONNECTION_DATA (connection);
2134   _dbus_assert (d != NULL);
2135
2136   while ((to_send = _dbus_list_get_first (&d->transaction_messages)))
2137     {
2138       /* only has an effect for the first MessageToSend listing this transaction */
2139       _dbus_list_remove (&to_send->transaction->connections,
2140                          connection);
2141
2142       _dbus_list_remove (&d->transaction_messages, to_send);
2143       message_to_send_free (connection, to_send);
2144     }
2145 }
2146
2147 /**
2148  * Converts the DBusError to a message reply
2149  */
2150 dbus_bool_t
2151 bus_transaction_send_error_reply (BusTransaction  *transaction,
2152                                   DBusConnection  *connection,
2153                                   const DBusError *error,
2154                                   DBusMessage     *in_reply_to)
2155 {
2156   DBusMessage *reply;
2157
2158   _dbus_assert (error != NULL);
2159   _DBUS_ASSERT_ERROR_IS_SET (error);
2160
2161   _dbus_verbose ("Sending error reply %s \"%s\"\n",
2162                  error->name, error->message);
2163
2164   reply = dbus_message_new_error (in_reply_to,
2165                                   error->name,
2166                                   error->message);
2167   if (reply == NULL)
2168     return FALSE;
2169
2170   if (!bus_transaction_send_from_driver (transaction, connection, reply))
2171     {
2172       dbus_message_unref (reply);
2173       return FALSE;
2174     }
2175
2176   dbus_message_unref (reply);
2177
2178   return TRUE;
2179 }
2180
2181 dbus_bool_t
2182 bus_transaction_add_cancel_hook (BusTransaction               *transaction,
2183                                  BusTransactionCancelFunction  cancel_function,
2184                                  void                         *data,
2185                                  DBusFreeFunction              free_data_function)
2186 {
2187   CancelHook *ch;
2188
2189   ch = dbus_new (CancelHook, 1);
2190   if (ch == NULL)
2191     return FALSE;
2192
2193   _dbus_verbose ("     adding cancel hook function = %p data = %p\n",
2194                  cancel_function, data);
2195
2196   ch->cancel_function = cancel_function;
2197   ch->data = data;
2198   ch->free_data_function = free_data_function;
2199
2200   /* It's important that the hooks get run in reverse order that they
2201    * were added
2202    */
2203   if (!_dbus_list_prepend (&transaction->cancel_hooks, ch))
2204     {
2205       dbus_free (ch);
2206       return FALSE;
2207     }
2208
2209   return TRUE;
2210 }