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
  35 static void bus_connection_remove_transactions (DBusConnection *connection);
  36
  37 typedef struct
  38 {
  39   BusExpireItem expire_item;
  40
  41   DBusConnection *will_get_reply;
  42   DBusConnection *will_send_reply;
  43
  44   dbus_uint32_t reply_serial;
  45
  46 } BusPendingReply;
  47
  48 struct BusConnections
  49 {
  50   int refcount;
  51   DBusList *completed;  /**< List of all completed connections */
  52   int n_completed;      /**< Length of completed list */
  53   DBusList *incomplete; /**< List of all not-yet-active connections */
  54   int n_incomplete;     /**< Length of incomplete list */
  55   BusContext *context;
  56   DBusHashTable *completed_by_user; /**< Number of completed connections for each UID */
  57   DBusTimeout *expire_timeout; /**< Timeout for expiring incomplete connections. */
  58   int stamp;                   /**< Incrementing number */
  59   BusExpireList *pending_replies; /**< List of pending replies */
  60 };
  61
  62 static dbus_int32_t connection_data_slot = -1;
  63
  64 typedef struct
  65 {
  66   BusConnections *connections;
  67   DBusList *link_in_connection_list;
  68   DBusConnection *connection;
  69   DBusList *services_owned;
  70   int n_services_owned;
  71   DBusList *match_rules;
  72   int n_match_rules;
  73   char *name;
  74   DBusList *transaction_messages; /**< Stuff we need to send as part of a transaction */
  75   DBusMessage *oom_message;
  76   DBusPreallocatedSend *oom_preallocated;
  77   BusClientPolicy *policy;
  78
  79   BusSELinuxID *selinux_id;
  80
  81   long connection_tv_sec;  /**< Time when we connected (seconds component) */
  82   long connection_tv_usec; /**< Time when we connected (microsec component) */
  83   int stamp;               /**< connections->stamp last time we were traversed */
  84 } BusConnectionData;
  85
  86 static dbus_bool_t bus_pending_reply_expired (BusExpireList *list,
  87                                               DBusList      *link,
  88                                               void          *data);
  89
  90 static void bus_connection_drop_pending_replies (BusConnections  *connections,
  91                                                  DBusConnection  *connection);
  92
  93 static dbus_bool_t expire_incomplete_timeout (void *data);
  94
  95 #define BUS_CONNECTION_DATA(connection) (dbus_connection_get_data ((connection), connection_data_slot))
  96
  97 static DBusLoop*
  98 connection_get_loop (DBusConnection *connection)
  99 {
 100   BusConnectionData *d;
 101
 102   d = BUS_CONNECTION_DATA (connection);
 103
 104   return bus_context_get_loop (d->connections->context);
 105 }
 106
 107
 108 static int
 109 get_connections_for_uid (BusConnections *connections,
 110                          dbus_uid_t      uid)
 111 {
 112   void *val;
 113   int current_count;
 114
 115   /* val is NULL is 0 when it isn't in the hash yet */
 116
 117   val = _dbus_hash_table_lookup_ulong (connections->completed_by_user,
 118                                        uid);
 119
 120   current_count = _DBUS_POINTER_TO_INT (val);
 121
 122   return current_count;
 123 }
 124
 125 static dbus_bool_t
 126 adjust_connections_for_uid (BusConnections *connections,
 127                             dbus_uid_t      uid,
 128                             int             adjustment)
 129 {
 130   int current_count;
 131
 132   current_count = get_connections_for_uid (connections, uid);
 133
 134   _dbus_verbose ("Adjusting connection count for UID " DBUS_UID_FORMAT
 135                  ": was %d adjustment %d making %d\n",
 136                  uid, current_count, adjustment, current_count + adjustment);
 137
 138   _dbus_assert (current_count >= 0);
 139
 140   current_count += adjustment;
 141
 142   _dbus_assert (current_count >= 0);
 143
 144   if (current_count == 0)
 145     {
 146       _dbus_hash_table_remove_ulong (connections->completed_by_user, uid);
 147       return TRUE;
 148     }
 149   else
 150     {
 151       dbus_bool_t retval;
 152
 153       retval = _dbus_hash_table_insert_ulong (connections->completed_by_user,
 154                                               uid, _DBUS_INT_TO_POINTER (current_count));
 155
 156       /* only positive adjustment can fail as otherwise
 157        * a hash entry should already exist
 158        */
 159       _dbus_assert (adjustment > 0 ||
 160                     (adjustment <= 0 && retval));
 161
 162       return retval;
 163     }
 164 }
 165
 166 void
 167 bus_connection_disconnected (DBusConnection *connection)
 168 {
 169   BusConnectionData *d;
 170   BusService *service;
 171   BusMatchmaker *matchmaker;
 172
 173   d = BUS_CONNECTION_DATA (connection);
 174   _dbus_assert (d != NULL);
 175
 176   _dbus_verbose ("%s disconnected, dropping all service ownership and releasing\n",
 177                  d->name ? d->name : "(inactive)");
 178
 179   /* Delete our match rules */
 180   if (d->n_match_rules > 0)
 181     {
 182       matchmaker = bus_context_get_matchmaker (d->connections->context);
 183       bus_matchmaker_disconnected (matchmaker, connection);
 184     }
 185
 186   /* Drop any service ownership. Unfortunately, this requires
 187    * memory allocation and there doesn't seem to be a good way to
 188    * handle it other than sleeping; we can't "fail" the operation of
 189    * disconnecting a client, and preallocating a broadcast "service is
 190    * now gone" message for every client-service pair seems kind of
 191    * involved.
 192    */
 193   while ((service = _dbus_list_get_last (&d->services_owned)))
 194     {
 195       BusTransaction *transaction;
 196       DBusError error;
 197
 198     retry:
 199
 200       dbus_error_init (&error);
 201
 202       while ((transaction = bus_transaction_new (d->connections->context)) == NULL)
 203         _dbus_wait_for_memory ();
 204
 205       if (!bus_service_remove_owner (service, connection,
 206                                      transaction, &error))
 207         {
 208           _DBUS_ASSERT_ERROR_IS_SET (&error);
 209
 210           if (dbus_error_has_name (&error, DBUS_ERROR_NO_MEMORY))
 211             {
 212               dbus_error_free (&error);
 213               bus_transaction_cancel_and_free (transaction);
 214               _dbus_wait_for_memory ();
 215               goto retry;
 216             }
 217           else
 218             {
 219               _dbus_verbose ("Failed to remove service owner: %s %s\n",
 220                              error.name, error.message);
 221               _dbus_assert_not_reached ("Removing service owner failed for non-memory-related reason");
 222             }
 223         }
 224
 225       bus_transaction_execute_and_free (transaction);
 226     }
 227
 228   bus_dispatch_remove_connection (connection);
 229
 230   /* no more watching */
 231   if (!dbus_connection_set_watch_functions (connection,
 232                                             NULL, NULL, NULL,
 233                                             connection,
 234                                             NULL))
 235     _dbus_assert_not_reached ("setting watch functions to NULL failed");
 236
 237   if (!dbus_connection_set_timeout_functions (connection,
 238                                               NULL, NULL, NULL,
 239                                               connection,
 240                                               NULL))
 241     _dbus_assert_not_reached ("setting timeout functions to NULL failed");
 242
 243   dbus_connection_set_unix_user_function (connection,
 244                                           NULL, NULL, NULL);
 245
 246   dbus_connection_set_dispatch_status_function (connection,
 247                                                 NULL, NULL, NULL);
 248
 249   bus_connection_remove_transactions (connection);
 250
 251   if (d->link_in_connection_list != NULL)
 252     {
 253       if (d->name != NULL)
 254         {
 255           unsigned long uid;
 256
 257           _dbus_list_remove_link (&d->connections->completed, d->link_in_connection_list);
 258           d->link_in_connection_list = NULL;
 259           d->connections->n_completed -= 1;
 260
 261           if (dbus_connection_get_unix_user (connection, &uid))
 262             {
 263               if (!adjust_connections_for_uid (d->connections,
 264                                                uid, -1))
 265                 _dbus_assert_not_reached ("adjusting downward should never fail");
 266             }
 267         }
 268       else
 269         {
 270           _dbus_list_remove_link (&d->connections->incomplete, d->link_in_connection_list);
 271           d->link_in_connection_list = NULL;
 272           d->connections->n_incomplete -= 1;
 273         }
 274
 275       _dbus_assert (d->connections->n_incomplete >= 0);
 276       _dbus_assert (d->connections->n_completed >= 0);
 277     }
 278
 279   bus_connection_drop_pending_replies (d->connections, connection);
 280
 281   /* frees "d" as side effect */
 282   dbus_connection_set_data (connection,
 283                             connection_data_slot,
 284                             NULL, NULL);
 285
 286   dbus_connection_unref (connection);
 287 }
 288
 289 static dbus_bool_t
 290 connection_watch_callback (DBusWatch     *watch,
 291                            unsigned int   condition,
 292                            void          *data)
 293 {
 294  /* FIXME this can be done in dbus-mainloop.c
 295   * if the code in activation.c for the babysitter
 296   * watch handler is fixed.
 297   */
 298
 299 #if 0
 300   _dbus_verbose ("Calling handle_watch\n");
 301 #endif
 302   return dbus_watch_handle (watch, condition);
 303 }
 304
 305 static dbus_bool_t
 306 add_connection_watch (DBusWatch      *watch,
 307                       void           *data)
 308 {
 309   DBusConnection *connection = data;
 310
 311   return _dbus_loop_add_watch (connection_get_loop (connection),
 312                                watch, connection_watch_callback, connection,
 313                                NULL);
 314 }
 315
 316 static void
 317 remove_connection_watch (DBusWatch      *watch,
 318                          void           *data)
 319 {
 320   DBusConnection *connection = data;
 321
 322   _dbus_loop_remove_watch (connection_get_loop (connection),
 323                            watch, connection_watch_callback, connection);
 324 }
 325
 326 static void
 327 connection_timeout_callback (DBusTimeout   *timeout,
 328                              void          *data)
 329 {
 330   /* DBusConnection *connection = data; */
 331
 332   /* can return FALSE on OOM but we just let it fire again later */
 333   dbus_timeout_handle (timeout);
 334 }
 335
 336 static dbus_bool_t
 337 add_connection_timeout (DBusTimeout    *timeout,
 338                         void           *data)
 339 {
 340   DBusConnection *connection = data;
 341
 342   return _dbus_loop_add_timeout (connection_get_loop (connection),
 343                                  timeout, connection_timeout_callback, connection, NULL);
 344 }
 345
 346 static void
 347 remove_connection_timeout (DBusTimeout    *timeout,
 348                            void           *data)
 349 {
 350   DBusConnection *connection = data;
 351
 352   _dbus_loop_remove_timeout (connection_get_loop (connection),
 353                              timeout, connection_timeout_callback, connection);
 354 }
 355
 356 static void
 357 dispatch_status_function (DBusConnection    *connection,
 358                           DBusDispatchStatus new_status,
 359                           void              *data)
 360 {
 361   DBusLoop *loop = data;
 362
 363   if (new_status != DBUS_DISPATCH_COMPLETE)
 364     {
 365       while (!_dbus_loop_queue_dispatch (loop, connection))
 366         _dbus_wait_for_memory ();
 367     }
 368 }
 369
 370 static dbus_bool_t
 371 allow_user_function (DBusConnection *connection,
 372                      unsigned long   uid,
 373                      void           *data)
 374 {
 375   BusConnectionData *d;
 376
 377   d = BUS_CONNECTION_DATA (connection);
 378
 379   _dbus_assert (d != NULL);
 380
 381   return bus_context_allow_user (d->connections->context, uid);
 382 }
 383
 384 static void
 385 free_connection_data (void *data)
 386 {
 387   BusConnectionData *d = data;
 388
 389   /* services_owned should be NULL since we should be disconnected */
 390   _dbus_assert (d->services_owned == NULL);
 391   _dbus_assert (d->n_services_owned == 0);
 392   /* similarly */
 393   _dbus_assert (d->transaction_messages == NULL);
 394
 395   if (d->oom_preallocated)
 396     dbus_connection_free_preallocated_send (d->connection, d->oom_preallocated);
 397
 398   if (d->oom_message)
 399     dbus_message_unref (d->oom_message);
 400
 401   if (d->policy)
 402     bus_client_policy_unref (d->policy);
 403
 404   if (d->selinux_id)
 405     bus_selinux_id_unref (d->selinux_id);
 406
 407   dbus_free (d->name);
 408
 409   dbus_free (d);
 410 }
 411
 412 static void
 413 call_timeout_callback (DBusTimeout   *timeout,
 414                        void          *data)
 415 {
 416   /* can return FALSE on OOM but we just let it fire again later */
 417   dbus_timeout_handle (timeout);
 418 }
 419
 420 BusConnections*
 421 bus_connections_new (BusContext *context)
 422 {
 423   BusConnections *connections;
 424
 425   if (!dbus_connection_allocate_data_slot (&connection_data_slot))
 426     goto failed_0;
 427
 428   connections = dbus_new0 (BusConnections, 1);
 429   if (connections == NULL)
 430     goto failed_1;
 431
 432   connections->completed_by_user = _dbus_hash_table_new (DBUS_HASH_ULONG,
 433                                                          NULL, NULL);
 434   if (connections->completed_by_user == NULL)
 435     goto failed_2;
 436
 437   connections->expire_timeout = _dbus_timeout_new (100, /* irrelevant */
 438                                                    expire_incomplete_timeout,
 439                                                    connections, NULL);
 440   if (connections->expire_timeout == NULL)
 441     goto failed_3;
 442
 443   _dbus_timeout_set_enabled (connections->expire_timeout, FALSE);
 444
 445   connections->pending_replies = bus_expire_list_new (bus_context_get_loop (context),
 446                                                       bus_context_get_reply_timeout (context),
 447                                                       bus_pending_reply_expired,
 448                                                       connections);
 449   if (connections->pending_replies == NULL)
 450     goto failed_4;
 451
 452   if (!_dbus_loop_add_timeout (bus_context_get_loop (context),
 453                                connections->expire_timeout,
 454                                call_timeout_callback, NULL, NULL))
 455     goto failed_5;
 456
 457   connections->refcount = 1;
 458   connections->context = context;
 459
 460   return connections;
 461
 462  failed_5:
 463   bus_expire_list_free (connections->pending_replies);
 464  failed_4:
 465   _dbus_timeout_unref (connections->expire_timeout);
 466  failed_3:
 467   _dbus_hash_table_unref (connections->completed_by_user);
 468  failed_2:
 469   dbus_free (connections);
 470  failed_1:
 471   dbus_connection_free_data_slot (&connection_data_slot);
 472  failed_0:
 473   return NULL;
 474 }
 475
 476 BusConnections *
 477 bus_connections_ref (BusConnections *connections)
 478 {
 479   _dbus_assert (connections->refcount > 0);
 480   connections->refcount += 1;
 481
 482   return connections;
 483 }
 484
 485 void
 486 bus_connections_unref (BusConnections *connections)
 487 {
 488   _dbus_assert (connections->refcount > 0);
 489   connections->refcount -= 1;
 490   if (connections->refcount == 0)
 491     {
 492       /* drop all incomplete */
 493       while (connections->incomplete != NULL)
 494         {
 495           DBusConnection *connection;
 496
 497           connection = connections->incomplete->data;
 498
 499           dbus_connection_ref (connection);
 500           dbus_connection_close (connection);
 501           bus_connection_disconnected (connection);
 502           dbus_connection_unref (connection);
 503         }
 504
 505       _dbus_assert (connections->n_incomplete == 0);
 506
 507       /* drop all real connections */
 508       while (connections->completed != NULL)
 509         {
 510           DBusConnection *connection;
 511
 512           connection = connections->completed->data;
 513
 514           dbus_connection_ref (connection);
 515           dbus_connection_close (connection);
 516           bus_connection_disconnected (connection);
 517           dbus_connection_unref (connection);
 518         }
 519
 520       _dbus_assert (connections->n_completed == 0);
 521
 522       bus_expire_list_free (connections->pending_replies);
 523
 524       _dbus_loop_remove_timeout (bus_context_get_loop (connections->context),
 525                                  connections->expire_timeout,
 526                                  call_timeout_callback, NULL);
 527
 528       _dbus_timeout_unref (connections->expire_timeout);
 529
 530       _dbus_hash_table_unref (connections->completed_by_user);
 531
 532       dbus_free (connections);
 533
 534       dbus_connection_free_data_slot (&connection_data_slot);
 535     }
 536 }
 537
 538 dbus_bool_t
 539 bus_connections_setup_connection (BusConnections *connections,
 540                                   DBusConnection *connection)
 541 {
 542   BusConnectionData *d;
 543   dbus_bool_t retval;
 544   DBusError error;
 545
 546   d = dbus_new0 (BusConnectionData, 1);
 547
 548   if (d == NULL)
 549     return FALSE;
 550
 551   d->connections = connections;
 552   d->connection = connection;
 553
 554   _dbus_get_current_time (&d->connection_tv_sec,
 555                           &d->connection_tv_usec);
 556
 557   _dbus_assert (connection_data_slot >= 0);
 558
 559   if (!dbus_connection_set_data (connection,
 560                                  connection_data_slot,
 561                                  d, free_connection_data))
 562     {
 563       dbus_free (d);
 564       return FALSE;
 565     }
 566
 567   dbus_connection_set_route_peer_messages (connection, TRUE);
 568
 569   retval = FALSE;
 570
 571   dbus_error_init (&error);
 572   d->selinux_id = bus_selinux_init_connection_id (connection,
 573                                                   &error);
 574   if (dbus_error_is_set (&error))
 575     {
 576       /* This is a bit bogus because we pretend all errors
 577        * are OOM; this is done because we know that in bus.c
 578        * an OOM error disconnects the connection, which is
 579        * the same thing we want on any other error.
 580        */
 581       dbus_error_free (&error);
 582       goto out;
 583     }
 584
 585   if (!dbus_connection_set_watch_functions (connection,
 586                                             add_connection_watch,
 587                                             remove_connection_watch,
 588                                             NULL,
 589                                             connection,
 590                                             NULL))
 591     goto out;
 592
 593   if (!dbus_connection_set_timeout_functions (connection,
 594                                               add_connection_timeout,
 595                                               remove_connection_timeout,
 596                                               NULL,
 597                                               connection, NULL))
 598     goto out;
 599
 600   dbus_connection_set_unix_user_function (connection,
 601                                           allow_user_function,
 602                                           NULL, NULL);
 603
 604   dbus_connection_set_dispatch_status_function (connection,
 605                                                 dispatch_status_function,
 606                                                 bus_context_get_loop (connections->context),
 607                                                 NULL);
 608
 609   d->link_in_connection_list = _dbus_list_alloc_link (connection);
 610   if (d->link_in_connection_list == NULL)
 611     goto out;
 612
 613   /* Setup the connection with the dispatcher */
 614   if (!bus_dispatch_add_connection (connection))
 615     goto out;
 616
 617   if (dbus_connection_get_dispatch_status (connection) != DBUS_DISPATCH_COMPLETE)
 618     {
 619       if (!_dbus_loop_queue_dispatch (bus_context_get_loop (connections->context), connection))
 620         {
 621           bus_dispatch_remove_connection (connection);
 622           goto out;
 623         }
 624     }
 625
 626   _dbus_list_append_link (&connections->incomplete, d->link_in_connection_list);
 627   connections->n_incomplete += 1;
 628
 629   dbus_connection_ref (connection);
 630
 631   /* Note that we might disconnect ourselves here, but it only takes
 632    * effect on return to the main loop. We call this to free up
 633    * expired connections if possible, and to queue the timeout for our
 634    * own expiration.
 635    */
 636   bus_connections_expire_incomplete (connections);
 637
 638   /* And we might also disconnect ourselves here, but again it
 639    * only takes effect on return to main loop.
 640    */
 641   if (connections->n_incomplete >
 642       bus_context_get_max_incomplete_connections (connections->context))
 643     {
 644       _dbus_verbose ("Number of incomplete connections exceeds max, dropping oldest one\n");
 645
 646       _dbus_assert (connections->incomplete != NULL);
 647       /* Disconnect the oldest unauthenticated connection.  FIXME
 648        * would it be more secure to drop a *random* connection?  This
 649        * algorithm seems to mean that if someone can create new
 650        * connections quickly enough, they can keep anyone else from
 651        * completing authentication. But random may or may not really
 652        * help with that, a more elaborate solution might be required.
 653        */
 654       dbus_connection_close (connections->incomplete->data);
 655     }
 656
 657   retval = TRUE;
 658
 659  out:
 660   if (!retval)
 661     {
 662       if (d->selinux_id)
 663         bus_selinux_id_unref (d->selinux_id);
 664       d->selinux_id = NULL;
 665
 666       if (!dbus_connection_set_watch_functions (connection,
 667                                                 NULL, NULL, NULL,
 668                                                 connection,
 669                                                 NULL))
 670         _dbus_assert_not_reached ("setting watch functions to NULL failed");
 671
 672       if (!dbus_connection_set_timeout_functions (connection,
 673                                                   NULL, NULL, NULL,
 674                                                   connection,
 675                                                   NULL))
 676         _dbus_assert_not_reached ("setting timeout functions to NULL failed");
 677
 678       dbus_connection_set_unix_user_function (connection,
 679                                               NULL, NULL, NULL);
 680
 681       dbus_connection_set_dispatch_status_function (connection,
 682                                                     NULL, NULL, NULL);
 683
 684       if (d->link_in_connection_list != NULL)
 685         {
 686           _dbus_assert (d->link_in_connection_list->next == NULL);
 687           _dbus_assert (d->link_in_connection_list->prev == NULL);
 688           _dbus_list_free_link (d->link_in_connection_list);
 689           d->link_in_connection_list = NULL;
 690         }
 691
 692       if (!dbus_connection_set_data (connection,
 693                                      connection_data_slot,
 694                                      NULL, NULL))
 695         _dbus_assert_not_reached ("failed to set connection data to null");
 696
 697       /* "d" has now been freed */
 698     }
 699
 700   return retval;
 701 }
 702
 703 void
 704 bus_connections_expire_incomplete (BusConnections *connections)
 705 {
 706   int next_interval;
 707
 708   next_interval = -1;
 709
 710   if (connections->incomplete != NULL)
 711     {
 712       long tv_sec, tv_usec;
 713       DBusList *link;
 714       int auth_timeout;
 715
 716       _dbus_get_current_time (&tv_sec, &tv_usec);
 717       auth_timeout = bus_context_get_auth_timeout (connections->context);
 718
 719       link = _dbus_list_get_first_link (&connections->incomplete);
 720       while (link != NULL)
 721         {
 722           DBusList *next = _dbus_list_get_next_link (&connections->incomplete, link);
 723           DBusConnection *connection;
 724           BusConnectionData *d;
 725           double elapsed;
 726
 727           connection = link->data;
 728
 729           d = BUS_CONNECTION_DATA (connection);
 730
 731           _dbus_assert (d != NULL);
 732
 733           elapsed = ELAPSED_MILLISECONDS_SINCE (d->connection_tv_sec,
 734                                                 d->connection_tv_usec,
 735                                                 tv_sec, tv_usec);
 736
 737           if (elapsed >= (double) auth_timeout)
 738             {
 739               _dbus_verbose ("Timing out authentication for connection %p\n", connection);
 740               dbus_connection_close (connection);
 741             }
 742           else
 743             {
 744               /* We can end the loop, since the connections are in oldest-first order */
 745               next_interval = ((double)auth_timeout) - elapsed;
 746               _dbus_verbose ("Connection %p authentication expires in %d milliseconds\n",
 747                              connection, next_interval);
 748
 749               break;
 750             }
 751
 752           link = next;
 753         }
 754     }
 755
 756   bus_expire_timeout_set_interval (connections->expire_timeout,
 757                                    next_interval);
 758 }
 759
 760 static dbus_bool_t
 761 expire_incomplete_timeout (void *data)
 762 {
 763   BusConnections *connections = data;
 764
 765   _dbus_verbose ("Running %s\n", _DBUS_FUNCTION_NAME);
 766
 767   /* note that this may remove the timeout */
 768   bus_connections_expire_incomplete (connections);
 769
 770   return TRUE;
 771 }
 772
 773 dbus_bool_t
 774 bus_connection_get_groups  (DBusConnection   *connection,
 775                             unsigned long   **groups,
 776                             int              *n_groups,
 777                             DBusError        *error)
 778 {
 779   BusConnectionData *d;
 780   unsigned long uid;
 781   DBusUserDatabase *user_database;
 782
 783   d = BUS_CONNECTION_DATA (connection);
 784
 785   _dbus_assert (d != NULL);
 786
 787   user_database = bus_context_get_user_database (d->connections->context);
 788
 789   *groups = NULL;
 790   *n_groups = 0;
 791
 792   if (dbus_connection_get_unix_user (connection, &uid))
 793     {
 794       if (!_dbus_user_database_get_groups (user_database,
 795                                            uid, groups, n_groups,
 796                                            error))
 797         {
 798           _DBUS_ASSERT_ERROR_IS_SET (error);
 799           _dbus_verbose ("Did not get any groups for UID %lu\n",
 800                          uid);
 801           return FALSE;
 802         }
 803       else
 804         {
 805           _dbus_verbose ("Got %d groups for UID %lu\n",
 806                          *n_groups, uid);
 807           return TRUE;
 808         }
 809     }
 810   else
 811     return TRUE; /* successfully got 0 groups */
 812 }
 813
 814 dbus_bool_t
 815 bus_connection_is_in_group (DBusConnection *connection,
 816                             unsigned long   gid)
 817 {
 818   int i;
 819   unsigned long *group_ids;
 820   int n_group_ids;
 821
 822   if (!bus_connection_get_groups (connection, &group_ids, &n_group_ids,
 823                                   NULL))
 824     return FALSE;
 825
 826   i = 0;
 827   while (i < n_group_ids)
 828     {
 829       if (group_ids[i] == gid)
 830         {
 831           dbus_free (group_ids);
 832           return TRUE;
 833         }
 834       ++i;
 835     }
 836
 837   dbus_free (group_ids);
 838   return FALSE;
 839 }
 840
 841 BusClientPolicy*
 842 bus_connection_get_policy (DBusConnection *connection)
 843 {
 844   BusConnectionData *d;
 845
 846   d = BUS_CONNECTION_DATA (connection);
 847
 848   _dbus_assert (d != NULL);
 849   _dbus_assert (d->policy != NULL);
 850
 851   return d->policy;
 852 }
 853
 854 static dbus_bool_t
 855 foreach_active (BusConnections               *connections,
 856                 BusConnectionForeachFunction  function,
 857                 void                         *data)
 858 {
 859   DBusList *link;
 860
 861   link = _dbus_list_get_first_link (&connections->completed);
 862   while (link != NULL)
 863     {
 864       DBusConnection *connection = link->data;
 865       DBusList *next = _dbus_list_get_next_link (&connections->completed, link);
 866
 867       if (!(* function) (connection, data))
 868         return FALSE;
 869
 870       link = next;
 871     }
 872
 873   return TRUE;
 874 }
 875
 876 static dbus_bool_t
 877 foreach_inactive (BusConnections               *connections,
 878                   BusConnectionForeachFunction  function,
 879                   void                         *data)
 880 {
 881   DBusList *link;
 882
 883   link = _dbus_list_get_first_link (&connections->incomplete);
 884   while (link != NULL)
 885     {
 886       DBusConnection *connection = link->data;
 887       DBusList *next = _dbus_list_get_next_link (&connections->incomplete, link);
 888
 889       if (!(* function) (connection, data))
 890         return FALSE;
 891
 892       link = next;
 893     }
 894
 895   return TRUE;
 896 }
 897
 898 /**
 899  * Calls function on each active connection; if the function returns
 900  * #FALSE, stops iterating. Active connections are authenticated
 901  * and have sent a Hello message.
 902  *
 903  * @param connections the connections object
 904  * @param function the function
 905  * @param data data to pass to it as a second arg
 906  */
 907 void
 908 bus_connections_foreach_active (BusConnections               *connections,
 909                                 BusConnectionForeachFunction  function,
 910                                 void                         *data)
 911 {
 912   foreach_active (connections, function, data);
 913 }
 914
 915 /**
 916  * Calls function on each connection; if the function returns
 917  * #FALSE, stops iterating.
 918  *
 919  * @param connections the connections object
 920  * @param function the function
 921  * @param data data to pass to it as a second arg
 922  */
 923 void
 924 bus_connections_foreach (BusConnections               *connections,
 925                          BusConnectionForeachFunction  function,
 926                          void                         *data)
 927 {
 928   if (!foreach_active (connections, function, data))
 929     return;
 930
 931   foreach_inactive (connections, function, data);
 932 }
 933
 934 BusContext*
 935 bus_connections_get_context (BusConnections *connections)
 936 {
 937   return connections->context;
 938 }
 939
 940 /*
 941  * This is used to avoid covering the same connection twice when
 942  * traversing connections. Note that it assumes we will
 943  * bus_connection_mark_stamp() each connection at least once per
 944  * INT_MAX increments of the global stamp, or wraparound would break
 945  * things.
 946  */
 947 void
 948 bus_connections_increment_stamp (BusConnections *connections)
 949 {
 950   connections->stamp += 1;
 951 }
 952
 953 /* Mark connection with current stamp, return TRUE if it
 954  * didn't already have that stamp
 955  */
 956 dbus_bool_t
 957 bus_connection_mark_stamp (DBusConnection *connection)
 958 {
 959   BusConnectionData *d;
 960
 961   d = BUS_CONNECTION_DATA (connection);
 962
 963   _dbus_assert (d != NULL);
 964
 965   if (d->stamp == d->connections->stamp)
 966     return FALSE;
 967   else
 968     {
 969       d->stamp = d->connections->stamp;
 970       return TRUE;
 971     }
 972 }
 973
 974 BusContext*
 975 bus_connection_get_context (DBusConnection *connection)
 976 {
 977   BusConnectionData *d;
 978
 979   d = BUS_CONNECTION_DATA (connection);
 980
 981   _dbus_assert (d != NULL);
 982
 983   return d->connections->context;
 984 }
 985
 986 BusConnections*
 987 bus_connection_get_connections (DBusConnection *connection)
 988 {
 989   BusConnectionData *d;
 990
 991   d = BUS_CONNECTION_DATA (connection);
 992
 993   _dbus_assert (d != NULL);
 994
 995   return d->connections;
 996 }
 997
 998 BusRegistry*
 999 bus_connection_get_registry (DBusConnection *connection)
1000 {
1001   BusConnectionData *d;
1002
1003   d = BUS_CONNECTION_DATA (connection);
1004
1005   _dbus_assert (d != NULL);
1006
1007   return bus_context_get_registry (d->connections->context);
1008 }
1009
1010 BusActivation*
1011 bus_connection_get_activation (DBusConnection *connection)
1012 {
1013   BusConnectionData *d;
1014
1015   d = BUS_CONNECTION_DATA (connection);
1016
1017   _dbus_assert (d != NULL);
1018
1019   return bus_context_get_activation (d->connections->context);
1020 }
1021
1022 BusMatchmaker*
1023 bus_connection_get_matchmaker (DBusConnection *connection)
1024 {
1025   BusConnectionData *d;
1026
1027   d = BUS_CONNECTION_DATA (connection);
1028
1029   _dbus_assert (d != NULL);
1030
1031   return bus_context_get_matchmaker (d->connections->context);
1032 }
1033
1034 BusSELinuxID*
1035 bus_connection_get_selinux_id (DBusConnection *connection)
1036 {
1037   BusConnectionData *d;
1038
1039   d = BUS_CONNECTION_DATA (connection);
1040
1041   _dbus_assert (d != NULL);
1042
1043   return d->selinux_id;
1044 }
1045
1046 /**
1047  * Checks whether the connection is registered with the message bus.
1048  *
1049  * @param connection the connection
1050  * @returns #TRUE if we're an active message bus participant
1051  */
1052 dbus_bool_t
1053 bus_connection_is_active (DBusConnection *connection)
1054 {
1055   BusConnectionData *d;
1056
1057   d = BUS_CONNECTION_DATA (connection);
1058
1059   return d != NULL && d->name != NULL;
1060 }
1061
1062 dbus_bool_t
1063 bus_connection_preallocate_oom_error (DBusConnection *connection)
1064 {
1065   DBusMessage *message;
1066   DBusPreallocatedSend *preallocated;
1067   BusConnectionData *d;
1068
1069   d = BUS_CONNECTION_DATA (connection);
1070
1071   _dbus_assert (d != NULL);
1072
1073   if (d->oom_preallocated != NULL)
1074     return TRUE;
1075
1076   preallocated = dbus_connection_preallocate_send (connection);
1077   if (preallocated == NULL)
1078     return FALSE;
1079
1080   message = dbus_message_new (DBUS_MESSAGE_TYPE_ERROR);
1081
1082   if (message == NULL)
1083     {
1084       dbus_connection_free_preallocated_send (connection, preallocated);
1085       return FALSE;
1086     }
1087
1088   /* d->name may be NULL, but that is OK */
1089   if (!dbus_message_set_error_name (message, DBUS_ERROR_NO_MEMORY) ||
1090       !dbus_message_set_destination (message, d->name) ||
1091       !dbus_message_set_sender (message,
1092                                 DBUS_SERVICE_DBUS))
1093     {
1094       dbus_connection_free_preallocated_send (connection, preallocated);
1095       dbus_message_unref (message);
1096       return FALSE;
1097     }
1098
1099   /* set reply serial to placeholder value just so space is already allocated
1100    * for it.
1101    */
1102   if (!dbus_message_set_reply_serial (message, 14))
1103     {
1104       dbus_connection_free_preallocated_send (connection, preallocated);
1105       dbus_message_unref (message);
1106       return FALSE;
1107     }
1108
1109   d->oom_message = message;
1110   d->oom_preallocated = preallocated;
1111
1112   return TRUE;
1113 }
1114
1115 void
1116 bus_connection_send_oom_error (DBusConnection *connection,
1117                                DBusMessage    *in_reply_to)
1118 {
1119   BusConnectionData *d;
1120
1121   d = BUS_CONNECTION_DATA (connection);
1122
1123   _dbus_assert (d != NULL);
1124   _dbus_assert (d->oom_message != NULL);
1125
1126   /* should always succeed since we set it to a placeholder earlier */
1127   if (!dbus_message_set_reply_serial (d->oom_message,
1128                                       dbus_message_get_serial (in_reply_to)))
1129     _dbus_assert_not_reached ("Failed to set reply serial for preallocated oom message");
1130
1131   _dbus_assert (dbus_message_get_sender (d->oom_message) != NULL);
1132
1133   dbus_connection_send_preallocated (connection, d->oom_preallocated,
1134                                      d->oom_message, NULL);
1135
1136   dbus_message_unref (d->oom_message);
1137   d->oom_message = NULL;
1138   d->oom_preallocated = NULL;
1139 }
1140
1141 void
1142 bus_connection_add_match_rule_link (DBusConnection *connection,
1143                                     DBusList       *link)
1144 {
1145   BusConnectionData *d;
1146
1147   d = BUS_CONNECTION_DATA (connection);
1148   _dbus_assert (d != NULL);
1149
1150   _dbus_list_append_link (&d->match_rules, link);
1151
1152   d->n_match_rules += 1;
1153 }
1154
1155 dbus_bool_t
1156 bus_connection_add_match_rule (DBusConnection *connection,
1157                                BusMatchRule   *rule)
1158 {
1159     DBusList *link;
1160
1161   link = _dbus_list_alloc_link (rule);
1162
1163   if (link == NULL)
1164     return FALSE;
1165
1166   bus_connection_add_match_rule_link (connection, link);
1167
1168   return TRUE;
1169 }
1170
1171 void
1172 bus_connection_remove_match_rule (DBusConnection *connection,
1173                                   BusMatchRule   *rule)
1174 {
1175   BusConnectionData *d;
1176
1177   d = BUS_CONNECTION_DATA (connection);
1178   _dbus_assert (d != NULL);
1179
1180   _dbus_list_remove_last (&d->match_rules, rule);
1181
1182   d->n_match_rules -= 1;
1183   _dbus_assert (d->n_match_rules >= 0);
1184 }
1185
1186 int
1187 bus_connection_get_n_match_rules (DBusConnection *connection)
1188 {
1189   BusConnectionData *d;
1190
1191   d = BUS_CONNECTION_DATA (connection);
1192   _dbus_assert (d != NULL);
1193
1194   return d->n_match_rules;
1195 }
1196
1197 void
1198 bus_connection_add_owned_service_link (DBusConnection *connection,
1199                                        DBusList       *link)
1200 {
1201   BusConnectionData *d;
1202
1203   d = BUS_CONNECTION_DATA (connection);
1204   _dbus_assert (d != NULL);
1205
1206   _dbus_list_append_link (&d->services_owned, link);
1207
1208   d->n_services_owned += 1;
1209 }
1210
1211 dbus_bool_t
1212 bus_connection_add_owned_service (DBusConnection *connection,
1213                                   BusService     *service)
1214 {
1215   DBusList *link;
1216
1217   link = _dbus_list_alloc_link (service);
1218
1219   if (link == NULL)
1220     return FALSE;
1221
1222   bus_connection_add_owned_service_link (connection, link);
1223
1224   return TRUE;
1225 }
1226
1227 void
1228 bus_connection_remove_owned_service (DBusConnection *connection,
1229                                      BusService     *service)
1230 {
1231   BusConnectionData *d;
1232
1233   d = BUS_CONNECTION_DATA (connection);
1234   _dbus_assert (d != NULL);
1235
1236   _dbus_list_remove_last (&d->services_owned, service);
1237
1238   d->n_services_owned -= 1;
1239   _dbus_assert (d->n_services_owned >= 0);
1240 }
1241
1242 int
1243 bus_connection_get_n_services_owned (DBusConnection *connection)
1244 {
1245   BusConnectionData *d;
1246
1247   d = BUS_CONNECTION_DATA (connection);
1248   _dbus_assert (d != NULL);
1249
1250   return d->n_services_owned;
1251 }
1252
1253 dbus_bool_t
1254 bus_connection_complete (DBusConnection   *connection,
1255                          const DBusString *name,
1256                          DBusError        *error)
1257 {
1258   BusConnectionData *d;
1259   unsigned long uid;
1260
1261   d = BUS_CONNECTION_DATA (connection);
1262   _dbus_assert (d != NULL);
1263   _dbus_assert (d->name == NULL);
1264   _dbus_assert (d->policy == NULL);
1265
1266   _dbus_assert (!bus_connection_is_active (connection));
1267
1268   if (!_dbus_string_copy_data (name, &d->name))
1269     {
1270       BUS_SET_OOM (error);
1271       return FALSE;
1272     }
1273
1274   _dbus_assert (d->name != NULL);
1275
1276   _dbus_verbose ("Name %s assigned to %p\n", d->name, connection);
1277
1278   d->policy = bus_context_create_client_policy (d->connections->context,
1279                                                 connection,
1280                                                 error);
1281
1282   /* we may have a NULL policy on OOM or error getting list of
1283    * groups for a user. In the latter case we don't handle it so
1284    * well currently, as it will just keep failing over and over.
1285    */
1286
1287   if (d->policy == NULL)
1288     {
1289       _dbus_verbose ("Failed to create security policy for connection %p\n",
1290                      connection);
1291       _DBUS_ASSERT_ERROR_IS_SET (error);
1292       dbus_free (d->name);
1293       d->name = NULL;
1294       return FALSE;
1295     }
1296
1297   if (dbus_connection_get_unix_user (connection, &uid))
1298     {
1299       if (!adjust_connections_for_uid (d->connections,
1300                                        uid, 1))
1301         {
1302           BUS_SET_OOM (error);
1303           dbus_free (d->name);
1304           d->name = NULL;
1305           return FALSE;
1306         }
1307     }
1308
1309   /* Now the connection is active, move it between lists */
1310   _dbus_list_unlink (&d->connections->incomplete,
1311                      d->link_in_connection_list);
1312   d->connections->n_incomplete -= 1;
1313   _dbus_list_append_link (&d->connections->completed,
1314                           d->link_in_connection_list);
1315   d->connections->n_completed += 1;
1316
1317   _dbus_assert (d->connections->n_incomplete >= 0);
1318   _dbus_assert (d->connections->n_completed > 0);
1319
1320   /* See if we can remove the timeout */
1321   bus_connections_expire_incomplete (d->connections);
1322
1323   _dbus_assert (bus_connection_is_active (connection));
1324
1325   return TRUE;
1326 }
1327
1328 const char *
1329 bus_connection_get_name (DBusConnection *connection)
1330 {
1331   BusConnectionData *d;
1332
1333   d = BUS_CONNECTION_DATA (connection);
1334   _dbus_assert (d != NULL);
1335
1336   return d->name;
1337 }
1338
1339 /**
1340  * Check whether completing the passed-in connection would
1341  * exceed limits, and if so set error and return #FALSE
1342  */
1343 dbus_bool_t
1344 bus_connections_check_limits (BusConnections  *connections,
1345                               DBusConnection  *requesting_completion,
1346                               DBusError       *error)
1347 {
1348   BusConnectionData *d;
1349   unsigned long uid;
1350
1351   d = BUS_CONNECTION_DATA (requesting_completion);
1352   _dbus_assert (d != NULL);
1353
1354   _dbus_assert (d->name == NULL);
1355
1356   if (connections->n_completed >=
1357       bus_context_get_max_completed_connections (connections->context))
1358     {
1359       dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
1360                       "The maximum number of active connections has been reached");
1361       return FALSE;
1362     }
1363
1364   if (dbus_connection_get_unix_user (requesting_completion, &uid))
1365     {
1366       if (get_connections_for_uid (connections, uid) >=
1367           bus_context_get_max_connections_per_user (connections->context))
1368         {
1369           dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
1370                           "The maximum number of active connections for UID %lu has been reached",
1371                           uid);
1372           return FALSE;
1373         }
1374     }
1375
1376   return TRUE;
1377 }
1378
1379 static void
1380 bus_pending_reply_free (BusPendingReply *pending)
1381 {
1382   _dbus_verbose ("Freeing pending reply %p, replier %p receiver %p serial %u\n",
1383                  pending,
1384                  pending->will_send_reply,
1385                  pending->will_get_reply,
1386                  pending->reply_serial);
1387
1388   dbus_free (pending);
1389 }
1390
1391 static dbus_bool_t
1392 bus_pending_reply_send_no_reply (BusConnections  *connections,
1393                                  BusTransaction  *transaction,
1394                                  BusPendingReply *pending)
1395 {
1396   DBusMessage *message;
1397   DBusMessageIter iter;
1398   dbus_bool_t retval;
1399   const char *errmsg;
1400
1401   retval = FALSE;
1402
1403   message = dbus_message_new (DBUS_MESSAGE_TYPE_ERROR);
1404   if (message == NULL)
1405     return FALSE;
1406
1407   dbus_message_set_no_reply (message, TRUE);
1408
1409   if (!dbus_message_set_reply_serial (message,
1410                                       pending->reply_serial))
1411     goto out;
1412
1413   if (!dbus_message_set_error_name (message,
1414                                     DBUS_ERROR_NO_REPLY))
1415     goto out;
1416
1417   errmsg = "Message did not receive a reply (timeout by message bus)";
1418   dbus_message_iter_init_append (message, &iter);
1419   if (!dbus_message_iter_append_basic (&iter, DBUS_TYPE_STRING, &errmsg))
1420     goto out;
1421
1422   if (!bus_transaction_send_from_driver (transaction, pending->will_get_reply,
1423                                          message))
1424     goto out;
1425
1426   retval = TRUE;
1427
1428  out:
1429   dbus_message_unref (message);
1430   return retval;
1431 }
1432
1433 static dbus_bool_t
1434 bus_pending_reply_expired (BusExpireList *list,
1435                            DBusList      *link,
1436                            void          *data)
1437 {
1438   BusPendingReply *pending = link->data;
1439   BusConnections *connections = data;
1440   BusTransaction *transaction;
1441
1442   /* No reply is forthcoming. So nuke it if we can. If not,
1443    * leave it in the list to try expiring again later when we
1444    * get more memory.
1445    */
1446
1447   _dbus_verbose ("Expiring pending reply %p, replier %p receiver %p serial %u\n",
1448                  pending,
1449                  pending->will_send_reply,
1450                  pending->will_get_reply,
1451                  pending->reply_serial);
1452
1453   transaction = bus_transaction_new (connections->context);
1454   if (transaction == NULL)
1455     return FALSE;
1456
1457   if (!bus_pending_reply_send_no_reply (connections,
1458                                         transaction,
1459                                         pending))
1460     {
1461       bus_transaction_cancel_and_free (transaction);
1462       return FALSE;
1463     }
1464
1465   _dbus_list_remove_link (&connections->pending_replies->items,
1466                           link);
1467   bus_pending_reply_free (pending);
1468   bus_transaction_execute_and_free (transaction);
1469
1470   return TRUE;
1471 }
1472
1473 static void
1474 bus_connection_drop_pending_replies (BusConnections  *connections,
1475                                      DBusConnection  *connection)
1476 {
1477   /* The DBusConnection is almost 100% finalized here, so you can't
1478    * do anything with it except check for pointer equality
1479    */
1480   DBusList *link;
1481
1482   _dbus_verbose ("Dropping pending replies that involve connection %p\n",
1483                  connection);
1484
1485   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1486   while (link != NULL)
1487     {
1488       DBusList *next;
1489       BusPendingReply *pending;
1490
1491       next = _dbus_list_get_next_link (&connections->pending_replies->items,
1492                                        link);
1493       pending = link->data;
1494
1495       if (pending->will_get_reply == connection)
1496         {
1497           /* We don't need to track this pending reply anymore */
1498
1499           _dbus_verbose ("Dropping pending reply %p, replier %p receiver %p serial %u\n",
1500                          pending,
1501                          pending->will_send_reply,
1502                          pending->will_get_reply,
1503                          pending->reply_serial);
1504
1505           _dbus_list_remove_link (&connections->pending_replies->items,
1506                                   link);
1507           bus_pending_reply_free (pending);
1508         }
1509       else if (pending->will_send_reply == connection)
1510         {
1511           /* The reply isn't going to be sent, so set things
1512            * up so it will be expired right away
1513            */
1514           _dbus_verbose ("Will expire pending reply %p, replier %p receiver %p serial %u\n",
1515                          pending,
1516                          pending->will_send_reply,
1517                          pending->will_get_reply,
1518                          pending->reply_serial);
1519
1520           pending->will_send_reply = NULL;
1521           pending->expire_item.added_tv_sec = 0;
1522           pending->expire_item.added_tv_usec = 0;
1523
1524           bus_expire_timeout_set_interval (connections->pending_replies->timeout,
1525                                            0);
1526         }
1527
1528       link = next;
1529     }
1530 }
1531
1532
1533 typedef struct
1534 {
1535   BusPendingReply *pending;
1536   BusConnections  *connections;
1537 } CancelPendingReplyData;
1538
1539 static void
1540 cancel_pending_reply (void *data)
1541 {
1542   CancelPendingReplyData *d = data;
1543
1544   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1545
1546   if (!_dbus_list_remove (&d->connections->pending_replies->items,
1547                           d->pending))
1548     _dbus_assert_not_reached ("pending reply did not exist to be cancelled");
1549
1550   bus_pending_reply_free (d->pending); /* since it's been cancelled */
1551 }
1552
1553 static void
1554 cancel_pending_reply_data_free (void *data)
1555 {
1556   CancelPendingReplyData *d = data;
1557
1558   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1559
1560   /* d->pending should be either freed or still
1561    * in the list of pending replies (owned by someone
1562    * else)
1563    */
1564
1565   dbus_free (d);
1566 }
1567
1568 /*
1569  * Record that a reply is allowed; return TRUE on success.
1570  */
1571 dbus_bool_t
1572 bus_connections_expect_reply (BusConnections  *connections,
1573                               BusTransaction  *transaction,
1574                               DBusConnection  *will_get_reply,
1575                               DBusConnection  *will_send_reply,
1576                               DBusMessage     *reply_to_this,
1577                               DBusError       *error)
1578 {
1579   BusPendingReply *pending;
1580   dbus_uint32_t reply_serial;
1581   DBusList *link;
1582   CancelPendingReplyData *cprd;
1583   int count;
1584
1585   _dbus_assert (will_get_reply != NULL);
1586   _dbus_assert (will_send_reply != NULL);
1587   _dbus_assert (reply_to_this != NULL);
1588
1589   if (dbus_message_get_no_reply (reply_to_this))
1590     return TRUE; /* we won't allow a reply, since client doesn't care for one. */
1591
1592   reply_serial = dbus_message_get_serial (reply_to_this);
1593
1594   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1595   count = 0;
1596   while (link != NULL)
1597     {
1598       pending = link->data;
1599
1600       if (pending->reply_serial == reply_serial &&
1601           pending->will_get_reply == will_get_reply &&
1602           pending->will_send_reply == will_send_reply)
1603         {
1604           dbus_set_error (error, DBUS_ERROR_ACCESS_DENIED,
1605                           "Message has the same reply serial as a currently-outstanding existing method call");
1606           return FALSE;
1607         }
1608
1609       link = _dbus_list_get_next_link (&connections->pending_replies->items,
1610                                        link);
1611       if (pending->will_get_reply == will_get_reply)
1612         ++count;
1613     }
1614
1615   if (count >=
1616       bus_context_get_max_replies_per_connection (connections->context))
1617     {
1618       dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
1619                       "The maximum number of pending replies per connection has been reached");
1620       return FALSE;
1621     }
1622
1623   pending = dbus_new0 (BusPendingReply, 1);
1624   if (pending == NULL)
1625     {
1626       BUS_SET_OOM (error);
1627       return FALSE;
1628     }
1629
1630 #ifdef DBUS_ENABLE_VERBOSE_MODE
1631   /* so we can see a not-yet-added pending reply */
1632   pending->expire_item.added_tv_sec = 1;
1633   pending->expire_item.added_tv_usec = 1;
1634 #endif
1635
1636   pending->will_get_reply = will_get_reply;
1637   pending->will_send_reply = will_send_reply;
1638   pending->reply_serial = reply_serial;
1639
1640   cprd = dbus_new0 (CancelPendingReplyData, 1);
1641   if (cprd == NULL)
1642     {
1643       BUS_SET_OOM (error);
1644       bus_pending_reply_free (pending);
1645       return FALSE;
1646     }
1647
1648   if (!_dbus_list_prepend (&connections->pending_replies->items,
1649                            pending))
1650     {
1651       BUS_SET_OOM (error);
1652       dbus_free (cprd);
1653       bus_pending_reply_free (pending);
1654       return FALSE;
1655     }
1656
1657   if (!bus_transaction_add_cancel_hook (transaction,
1658                                         cancel_pending_reply,
1659                                         cprd,
1660                                         cancel_pending_reply_data_free))
1661     {
1662       BUS_SET_OOM (error);
1663       _dbus_list_remove (&connections->pending_replies->items, pending);
1664       dbus_free (cprd);
1665       bus_pending_reply_free (pending);
1666       return FALSE;
1667     }
1668
1669   cprd->pending = pending;
1670   cprd->connections = connections;
1671
1672   _dbus_get_current_time (&pending->expire_item.added_tv_sec,
1673                           &pending->expire_item.added_tv_usec);
1674
1675   _dbus_verbose ("Added pending reply %p, replier %p receiver %p serial %u\n",
1676                  pending,
1677                  pending->will_send_reply,
1678                  pending->will_get_reply,
1679                  pending->reply_serial);
1680
1681   return TRUE;
1682 }
1683
1684 typedef struct
1685 {
1686   DBusList        *link;
1687   BusConnections  *connections;
1688 } CheckPendingReplyData;
1689
1690 static void
1691 cancel_check_pending_reply (void *data)
1692 {
1693   CheckPendingReplyData *d = data;
1694
1695   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1696
1697   _dbus_list_prepend_link (&d->connections->pending_replies->items,
1698                            d->link);
1699   d->link = NULL;
1700 }
1701
1702 static void
1703 check_pending_reply_data_free (void *data)
1704 {
1705   CheckPendingReplyData *d = data;
1706
1707   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1708
1709   if (d->link != NULL)
1710     {
1711       BusPendingReply *pending = d->link->data;
1712
1713       _dbus_assert (_dbus_list_find_last (&d->connections->pending_replies->items,
1714                                           pending) == NULL);
1715
1716       bus_pending_reply_free (pending);
1717       _dbus_list_free_link (d->link);
1718     }
1719
1720   dbus_free (d);
1721 }
1722
1723 /*
1724  * Check whether a reply is allowed, remove BusPendingReply
1725  * if so, return TRUE if so.
1726  */
1727 dbus_bool_t
1728 bus_connections_check_reply (BusConnections *connections,
1729                              BusTransaction *transaction,
1730                              DBusConnection *sending_reply,
1731                              DBusConnection *receiving_reply,
1732                              DBusMessage    *reply,
1733                              DBusError      *error)
1734 {
1735   CheckPendingReplyData *cprd;
1736   DBusList *link;
1737   dbus_uint32_t reply_serial;
1738
1739   _dbus_assert (sending_reply != NULL);
1740   _dbus_assert (receiving_reply != NULL);
1741
1742   reply_serial = dbus_message_get_reply_serial (reply);
1743
1744   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1745   while (link != NULL)
1746     {
1747       BusPendingReply *pending = link->data;
1748
1749       if (pending->reply_serial == reply_serial &&
1750           pending->will_get_reply == receiving_reply &&
1751           pending->will_send_reply == sending_reply)
1752         {
1753           _dbus_verbose ("Found pending reply with serial %u\n", reply_serial);
1754           break;
1755         }
1756
1757       link = _dbus_list_get_next_link (&connections->pending_replies->items,
1758                                        link);
1759     }
1760
1761   if (link == NULL)
1762     {
1763       _dbus_verbose ("No pending reply expected\n");
1764
1765       return FALSE;
1766     }
1767
1768   cprd = dbus_new0 (CheckPendingReplyData, 1);
1769   if (cprd == NULL)
1770     {
1771       BUS_SET_OOM (error);
1772       return FALSE;
1773     }
1774
1775   if (!bus_transaction_add_cancel_hook (transaction,
1776                                         cancel_check_pending_reply,
1777                                         cprd,
1778                                         check_pending_reply_data_free))
1779     {
1780       BUS_SET_OOM (error);
1781       dbus_free (cprd);
1782       return FALSE;
1783     }
1784
1785   cprd->link = link;
1786   cprd->connections = connections;
1787
1788   _dbus_list_unlink (&connections->pending_replies->items,
1789                      link);
1790
1791   _dbus_assert (_dbus_list_find_last (&connections->pending_replies->items,
1792                                       link->data) == NULL);
1793
1794   return TRUE;
1795 }
1796
1797 /*
1798  * Transactions
1799  *
1800  * Note that this is fairly fragile; in particular, don't try to use
1801  * one transaction across any main loop iterations.
1802  */
1803
1804 typedef struct
1805 {
1806   BusTransaction *transaction;
1807   DBusMessage    *message;
1808   DBusPreallocatedSend *preallocated;
1809 } MessageToSend;
1810
1811 typedef struct
1812 {
1813   BusTransactionCancelFunction cancel_function;
1814   DBusFreeFunction free_data_function;
1815   void *data;
1816 } CancelHook;
1817
1818 struct BusTransaction
1819 {
1820   DBusList *connections;
1821   BusContext *context;
1822   DBusList *cancel_hooks;
1823 };
1824
1825 static void
1826 message_to_send_free (DBusConnection *connection,
1827                       MessageToSend  *to_send)
1828 {
1829   if (to_send->message)
1830     dbus_message_unref (to_send->message);
1831
1832   if (to_send->preallocated)
1833     dbus_connection_free_preallocated_send (connection, to_send->preallocated);
1834
1835   dbus_free (to_send);
1836 }
1837
1838 static void
1839 cancel_hook_cancel (void *element,
1840                     void *data)
1841 {
1842   CancelHook *ch = element;
1843
1844   _dbus_verbose ("Running transaction cancel hook\n");
1845
1846   if (ch->cancel_function)
1847     (* ch->cancel_function) (ch->data);
1848 }
1849
1850 static void
1851 cancel_hook_free (void *element,
1852                   void *data)
1853 {
1854   CancelHook *ch = element;
1855
1856   if (ch->free_data_function)
1857     (* ch->free_data_function) (ch->data);
1858
1859   dbus_free (ch);
1860 }
1861
1862 static void
1863 free_cancel_hooks (BusTransaction *transaction)
1864 {
1865   _dbus_list_foreach (&transaction->cancel_hooks,
1866                       cancel_hook_free, NULL);
1867
1868   _dbus_list_clear (&transaction->cancel_hooks);
1869 }
1870
1871 BusTransaction*
1872 bus_transaction_new (BusContext *context)
1873 {
1874   BusTransaction *transaction;
1875
1876   transaction = dbus_new0 (BusTransaction, 1);
1877   if (transaction == NULL)
1878     return NULL;
1879
1880   transaction->context = context;
1881
1882   return transaction;
1883 }
1884
1885 BusContext*
1886 bus_transaction_get_context (BusTransaction  *transaction)
1887 {
1888   return transaction->context;
1889 }
1890
1891 BusConnections*
1892 bus_transaction_get_connections (BusTransaction  *transaction)
1893 {
1894   return bus_context_get_connections (transaction->context);
1895 }
1896
1897 dbus_bool_t
1898 bus_transaction_send_from_driver (BusTransaction *transaction,
1899                                   DBusConnection *connection,
1900                                   DBusMessage    *message)
1901 {
1902   /* We have to set the sender to the driver, and have
1903    * to check security policy since it was not done in
1904    * dispatch.c
1905    */
1906   _dbus_verbose ("Sending %s %s %s from driver\n",
1907                  dbus_message_get_interface (message) ?
1908                  dbus_message_get_interface (message) : "(no interface)",
1909                  dbus_message_get_member (message) ?
1910                  dbus_message_get_member (message) : "(no member)",
1911                  dbus_message_get_error_name (message) ?
1912                  dbus_message_get_error_name (message) : "(no error name)");
1913
1914   if (!dbus_message_set_sender (message, DBUS_SERVICE_DBUS))
1915     return FALSE;
1916
1917   if (bus_connection_is_active (connection))
1918     {
1919       if (!dbus_message_set_destination (message,
1920                                          bus_connection_get_name (connection)))
1921         return FALSE;
1922     }
1923
1924   /* bus driver never wants a reply */
1925   dbus_message_set_no_reply (message, TRUE);
1926
1927   /* If security policy doesn't allow the message, we silently
1928    * eat it; the driver doesn't care about getting a reply.
1929    */
1930   if (!bus_context_check_security_policy (bus_transaction_get_context (transaction),
1931                                           transaction,
1932                                           NULL, connection, connection, message, NULL))
1933     return TRUE;
1934
1935   return bus_transaction_send (transaction, connection, message);
1936 }
1937
1938 dbus_bool_t
1939 bus_transaction_send (BusTransaction *transaction,
1940                       DBusConnection *connection,
1941                       DBusMessage    *message)
1942 {
1943   MessageToSend *to_send;
1944   BusConnectionData *d;
1945   DBusList *link;
1946
1947   _dbus_verbose ("  trying to add %s interface=%s member=%s error=%s to transaction%s\n",
1948                  dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_ERROR ? "error" :
1949                  dbus_message_get_reply_serial (message) != 0 ? "reply" :
1950                  "message",
1951                  dbus_message_get_interface (message) ?
1952                  dbus_message_get_interface (message) : "(unset)",
1953                  dbus_message_get_member (message) ?
1954                  dbus_message_get_member (message) : "(unset)",
1955                  dbus_message_get_error_name (message) ?
1956                  dbus_message_get_error_name (message) : "(unset)",
1957                  dbus_connection_get_is_connected (connection) ?
1958                  "" : " (disconnected)");
1959
1960   _dbus_assert (dbus_message_get_sender (message) != NULL);
1961
1962   if (!dbus_connection_get_is_connected (connection))
1963     return TRUE; /* silently ignore disconnected connections */
1964
1965   d = BUS_CONNECTION_DATA (connection);
1966   _dbus_assert (d != NULL);
1967
1968   to_send = dbus_new (MessageToSend, 1);
1969   if (to_send == NULL)
1970     {
1971       return FALSE;
1972     }
1973
1974   to_send->preallocated = dbus_connection_preallocate_send (connection);
1975   if (to_send->preallocated == NULL)
1976     {
1977       dbus_free (to_send);
1978       return FALSE;
1979     }
1980
1981   dbus_message_ref (message);
1982   to_send->message = message;
1983   to_send->transaction = transaction;
1984
1985   _dbus_verbose ("about to prepend message\n");
1986
1987   if (!_dbus_list_prepend (&d->transaction_messages, to_send))
1988     {
1989       message_to_send_free (connection, to_send);
1990       return FALSE;
1991     }
1992
1993   _dbus_verbose ("prepended message\n");
1994
1995   /* See if we already had this connection in the list
1996    * for this transaction. If we have a pending message,
1997    * then we should already be in transaction->connections
1998    */
1999   link = _dbus_list_get_first_link (&d->transaction_messages);
2000   _dbus_assert (link->data == to_send);
2001   link = _dbus_list_get_next_link (&d->transaction_messages, link);
2002   while (link != NULL)
2003     {
2004       MessageToSend *m = link->data;
2005       DBusList *next = _dbus_list_get_next_link (&d->transaction_messages, link);
2006
2007       if (m->transaction == transaction)
2008         break;
2009
2010       link = next;
2011     }
2012
2013   if (link == NULL)
2014     {
2015       if (!_dbus_list_prepend (&transaction->connections, connection))
2016         {
2017           _dbus_list_remove (&d->transaction_messages, to_send);
2018           message_to_send_free (connection, to_send);
2019           return FALSE;
2020         }
2021     }
2022
2023   return TRUE;
2024 }
2025
2026 static void
2027 connection_cancel_transaction (DBusConnection *connection,
2028                                BusTransaction *transaction)
2029 {
2030   DBusList *link;
2031   BusConnectionData *d;
2032
2033   d = BUS_CONNECTION_DATA (connection);
2034   _dbus_assert (d != NULL);
2035
2036   link = _dbus_list_get_first_link (&d->transaction_messages);
2037   while (link != NULL)
2038     {
2039       MessageToSend *m = link->data;
2040       DBusList *next = _dbus_list_get_next_link (&d->transaction_messages, link);
2041
2042       if (m->transaction == transaction)
2043         {
2044           _dbus_list_remove_link (&d->transaction_messages,
2045                                   link);
2046
2047           message_to_send_free (connection, m);
2048         }
2049
2050       link = next;
2051     }
2052 }
2053
2054 void
2055 bus_transaction_cancel_and_free (BusTransaction *transaction)
2056 {
2057   DBusConnection *connection;
2058
2059   _dbus_verbose ("TRANSACTION: cancelled\n");
2060
2061   while ((connection = _dbus_list_pop_first (&transaction->connections)))
2062     connection_cancel_transaction (connection, transaction);
2063
2064   _dbus_assert (transaction->connections == NULL);
2065
2066   _dbus_list_foreach (&transaction->cancel_hooks,
2067                       cancel_hook_cancel, NULL);
2068
2069   free_cancel_hooks (transaction);
2070
2071   dbus_free (transaction);
2072 }
2073
2074 static void
2075 connection_execute_transaction (DBusConnection *connection,
2076                                 BusTransaction *transaction)
2077 {
2078   DBusList *link;
2079   BusConnectionData *d;
2080
2081   d = BUS_CONNECTION_DATA (connection);
2082   _dbus_assert (d != NULL);
2083
2084   /* Send the queue in order (FIFO) */
2085   link = _dbus_list_get_last_link (&d->transaction_messages);
2086   while (link != NULL)
2087     {
2088       MessageToSend *m = link->data;
2089       DBusList *prev = _dbus_list_get_prev_link (&d->transaction_messages, link);
2090
2091       if (m->transaction == transaction)
2092         {
2093           _dbus_list_remove_link (&d->transaction_messages,
2094                                   link);
2095
2096           _dbus_assert (dbus_message_get_sender (m->message) != NULL);
2097
2098           dbus_connection_send_preallocated (connection,
2099                                              m->preallocated,
2100                                              m->message,
2101                                              NULL);
2102
2103           m->preallocated = NULL; /* so we don't double-free it */
2104
2105           message_to_send_free (connection, m);
2106         }
2107
2108       link = prev;
2109     }
2110 }
2111
2112 void
2113 bus_transaction_execute_and_free (BusTransaction *transaction)
2114 {
2115   /* For each connection in transaction->connections
2116    * send the messages
2117    */
2118   DBusConnection *connection;
2119
2120   _dbus_verbose ("TRANSACTION: executing\n");
2121
2122   while ((connection = _dbus_list_pop_first (&transaction->connections)))
2123     connection_execute_transaction (connection, transaction);
2124
2125   _dbus_assert (transaction->connections == NULL);
2126
2127   free_cancel_hooks (transaction);
2128
2129   dbus_free (transaction);
2130 }
2131
2132 static void
2133 bus_connection_remove_transactions (DBusConnection *connection)
2134 {
2135   MessageToSend *to_send;
2136   BusConnectionData *d;
2137
2138   d = BUS_CONNECTION_DATA (connection);
2139   _dbus_assert (d != NULL);
2140
2141   while ((to_send = _dbus_list_get_first (&d->transaction_messages)))
2142     {
2143       /* only has an effect for the first MessageToSend listing this transaction */
2144       _dbus_list_remove (&to_send->transaction->connections,
2145                          connection);
2146
2147       _dbus_list_remove (&d->transaction_messages, to_send);
2148       message_to_send_free (connection, to_send);
2149     }
2150 }
2151
2152 /**
2153  * Converts the DBusError to a message reply
2154  */
2155 dbus_bool_t
2156 bus_transaction_send_error_reply (BusTransaction  *transaction,
2157                                   DBusConnection  *connection,
2158                                   const DBusError *error,
2159                                   DBusMessage     *in_reply_to)
2160 {
2161   DBusMessage *reply;
2162
2163   _dbus_assert (error != NULL);
2164   _DBUS_ASSERT_ERROR_IS_SET (error);
2165
2166   _dbus_verbose ("Sending error reply %s \"%s\"\n",
2167                  error->name, error->message);
2168
2169   reply = dbus_message_new_error (in_reply_to,
2170                                   error->name,
2171                                   error->message);
2172   if (reply == NULL)
2173     return FALSE;
2174
2175   if (!bus_transaction_send_from_driver (transaction, connection, reply))
2176     {
2177       dbus_message_unref (reply);
2178       return FALSE;
2179     }
2180
2181   dbus_message_unref (reply);
2182
2183   return TRUE;
2184 }
2185
2186 dbus_bool_t
2187 bus_transaction_add_cancel_hook (BusTransaction               *transaction,
2188                                  BusTransactionCancelFunction  cancel_function,
2189                                  void                         *data,
2190                                  DBusFreeFunction              free_data_function)
2191 {
2192   CancelHook *ch;
2193
2194   ch = dbus_new (CancelHook, 1);
2195   if (ch == NULL)
2196     return FALSE;
2197
2198   _dbus_verbose ("     adding cancel hook function = %p data = %p\n",
2199                  cancel_function, data);
2200
2201   ch->cancel_function = cancel_function;
2202   ch->data = data;
2203   ch->free_data_function = free_data_function;
2204
2205   /* It's important that the hooks get run in reverse order that they
2206    * were added
2207    */
2208   if (!_dbus_list_prepend (&transaction->cancel_hooks, ch))
2209     {
2210       dbus_free (ch);
2211       return FALSE;
2212     }
2213
2214   return TRUE;
2215 }