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   dbus_connection_set_windows_user_function (connection,
 246                                              NULL, NULL, NULL);
 247
 248   dbus_connection_set_dispatch_status_function (connection,
 249                                                 NULL, NULL, NULL);
 250
 251   bus_connection_remove_transactions (connection);
 252
 253   if (d->link_in_connection_list != NULL)
 254     {
 255       if (d->name != NULL)
 256         {
 257           unsigned long uid;
 258
 259           _dbus_list_remove_link (&d->connections->completed, d->link_in_connection_list);
 260           d->link_in_connection_list = NULL;
 261           d->connections->n_completed -= 1;
 262
 263           if (dbus_connection_get_unix_user (connection, &uid))
 264             {
 265               if (!adjust_connections_for_uid (d->connections,
 266                                                uid, -1))
 267                 _dbus_assert_not_reached ("adjusting downward should never fail");
 268             }
 269         }
 270       else
 271         {
 272           _dbus_list_remove_link (&d->connections->incomplete, d->link_in_connection_list);
 273           d->link_in_connection_list = NULL;
 274           d->connections->n_incomplete -= 1;
 275         }
 276
 277       _dbus_assert (d->connections->n_incomplete >= 0);
 278       _dbus_assert (d->connections->n_completed >= 0);
 279     }
 280
 281   bus_connection_drop_pending_replies (d->connections, connection);
 282
 283   /* frees "d" as side effect */
 284   dbus_connection_set_data (connection,
 285                             connection_data_slot,
 286                             NULL, NULL);
 287
 288   dbus_connection_unref (connection);
 289 }
 290
 291 static dbus_bool_t
 292 connection_watch_callback (DBusWatch     *watch,
 293                            unsigned int   condition,
 294                            void          *data)
 295 {
 296  /* FIXME this can be done in dbus-mainloop.c
 297   * if the code in activation.c for the babysitter
 298   * watch handler is fixed.
 299   */
 300
 301 #if 0
 302   _dbus_verbose ("Calling handle_watch\n");
 303 #endif
 304   return dbus_watch_handle (watch, condition);
 305 }
 306
 307 static dbus_bool_t
 308 add_connection_watch (DBusWatch      *watch,
 309                       void           *data)
 310 {
 311   DBusConnection *connection = data;
 312
 313   return _dbus_loop_add_watch (connection_get_loop (connection),
 314                                watch, connection_watch_callback, connection,
 315                                NULL);
 316 }
 317
 318 static void
 319 remove_connection_watch (DBusWatch      *watch,
 320                          void           *data)
 321 {
 322   DBusConnection *connection = data;
 323
 324   _dbus_loop_remove_watch (connection_get_loop (connection),
 325                            watch, connection_watch_callback, connection);
 326 }
 327
 328 static void
 329 connection_timeout_callback (DBusTimeout   *timeout,
 330                              void          *data)
 331 {
 332   /* DBusConnection *connection = data; */
 333
 334   /* can return FALSE on OOM but we just let it fire again later */
 335   dbus_timeout_handle (timeout);
 336 }
 337
 338 static dbus_bool_t
 339 add_connection_timeout (DBusTimeout    *timeout,
 340                         void           *data)
 341 {
 342   DBusConnection *connection = data;
 343
 344   return _dbus_loop_add_timeout (connection_get_loop (connection),
 345                                  timeout, connection_timeout_callback, connection, NULL);
 346 }
 347
 348 static void
 349 remove_connection_timeout (DBusTimeout    *timeout,
 350                            void           *data)
 351 {
 352   DBusConnection *connection = data;
 353
 354   _dbus_loop_remove_timeout (connection_get_loop (connection),
 355                              timeout, connection_timeout_callback, connection);
 356 }
 357
 358 static void
 359 dispatch_status_function (DBusConnection    *connection,
 360                           DBusDispatchStatus new_status,
 361                           void              *data)
 362 {
 363   DBusLoop *loop = data;
 364
 365   if (new_status != DBUS_DISPATCH_COMPLETE)
 366     {
 367       while (!_dbus_loop_queue_dispatch (loop, connection))
 368         _dbus_wait_for_memory ();
 369     }
 370 }
 371
 372 static dbus_bool_t
 373 allow_unix_user_function (DBusConnection *connection,
 374                           unsigned long   uid,
 375                           void           *data)
 376 {
 377   BusConnectionData *d;
 378
 379   d = BUS_CONNECTION_DATA (connection);
 380
 381   _dbus_assert (d != NULL);
 382
 383   return bus_context_allow_unix_user (d->connections->context, uid);
 384 }
 385
 386 static void
 387 free_connection_data (void *data)
 388 {
 389   BusConnectionData *d = data;
 390
 391   /* services_owned should be NULL since we should be disconnected */
 392   _dbus_assert (d->services_owned == NULL);
 393   _dbus_assert (d->n_services_owned == 0);
 394   /* similarly */
 395   _dbus_assert (d->transaction_messages == NULL);
 396
 397   if (d->oom_preallocated)
 398     dbus_connection_free_preallocated_send (d->connection, d->oom_preallocated);
 399
 400   if (d->oom_message)
 401     dbus_message_unref (d->oom_message);
 402
 403   if (d->policy)
 404     bus_client_policy_unref (d->policy);
 405
 406   if (d->selinux_id)
 407     bus_selinux_id_unref (d->selinux_id);
 408
 409   dbus_free (d->name);
 410
 411   dbus_free (d);
 412 }
 413
 414 static void
 415 call_timeout_callback (DBusTimeout   *timeout,
 416                        void          *data)
 417 {
 418   /* can return FALSE on OOM but we just let it fire again later */
 419   dbus_timeout_handle (timeout);
 420 }
 421
 422 BusConnections*
 423 bus_connections_new (BusContext *context)
 424 {
 425   BusConnections *connections;
 426
 427   if (!dbus_connection_allocate_data_slot (&connection_data_slot))
 428     goto failed_0;
 429
 430   connections = dbus_new0 (BusConnections, 1);
 431   if (connections == NULL)
 432     goto failed_1;
 433
 434   connections->completed_by_user = _dbus_hash_table_new (DBUS_HASH_ULONG,
 435                                                          NULL, NULL);
 436   if (connections->completed_by_user == NULL)
 437     goto failed_2;
 438
 439   connections->expire_timeout = _dbus_timeout_new (100, /* irrelevant */
 440                                                    expire_incomplete_timeout,
 441                                                    connections, NULL);
 442   if (connections->expire_timeout == NULL)
 443     goto failed_3;
 444
 445   _dbus_timeout_set_enabled (connections->expire_timeout, FALSE);
 446
 447   connections->pending_replies = bus_expire_list_new (bus_context_get_loop (context),
 448                                                       bus_context_get_reply_timeout (context),
 449                                                       bus_pending_reply_expired,
 450                                                       connections);
 451   if (connections->pending_replies == NULL)
 452     goto failed_4;
 453
 454   if (!_dbus_loop_add_timeout (bus_context_get_loop (context),
 455                                connections->expire_timeout,
 456                                call_timeout_callback, NULL, NULL))
 457     goto failed_5;
 458
 459   connections->refcount = 1;
 460   connections->context = context;
 461
 462   return connections;
 463
 464  failed_5:
 465   bus_expire_list_free (connections->pending_replies);
 466  failed_4:
 467   _dbus_timeout_unref (connections->expire_timeout);
 468  failed_3:
 469   _dbus_hash_table_unref (connections->completed_by_user);
 470  failed_2:
 471   dbus_free (connections);
 472  failed_1:
 473   dbus_connection_free_data_slot (&connection_data_slot);
 474  failed_0:
 475   return NULL;
 476 }
 477
 478 BusConnections *
 479 bus_connections_ref (BusConnections *connections)
 480 {
 481   _dbus_assert (connections->refcount > 0);
 482   connections->refcount += 1;
 483
 484   return connections;
 485 }
 486
 487 void
 488 bus_connections_unref (BusConnections *connections)
 489 {
 490   _dbus_assert (connections->refcount > 0);
 491   connections->refcount -= 1;
 492   if (connections->refcount == 0)
 493     {
 494       /* drop all incomplete */
 495       while (connections->incomplete != NULL)
 496         {
 497           DBusConnection *connection;
 498
 499           connection = connections->incomplete->data;
 500
 501           dbus_connection_ref (connection);
 502           dbus_connection_close (connection);
 503           bus_connection_disconnected (connection);
 504           dbus_connection_unref (connection);
 505         }
 506
 507       _dbus_assert (connections->n_incomplete == 0);
 508
 509       /* drop all real connections */
 510       while (connections->completed != NULL)
 511         {
 512           DBusConnection *connection;
 513
 514           connection = connections->completed->data;
 515
 516           dbus_connection_ref (connection);
 517           dbus_connection_close (connection);
 518           bus_connection_disconnected (connection);
 519           dbus_connection_unref (connection);
 520         }
 521
 522       _dbus_assert (connections->n_completed == 0);
 523
 524       bus_expire_list_free (connections->pending_replies);
 525
 526       _dbus_loop_remove_timeout (bus_context_get_loop (connections->context),
 527                                  connections->expire_timeout,
 528                                  call_timeout_callback, NULL);
 529
 530       _dbus_timeout_unref (connections->expire_timeout);
 531
 532       _dbus_hash_table_unref (connections->completed_by_user);
 533
 534       dbus_free (connections);
 535
 536       dbus_connection_free_data_slot (&connection_data_slot);
 537     }
 538 }
 539
 540 dbus_bool_t
 541 bus_connections_setup_connection (BusConnections *connections,
 542                                   DBusConnection *connection)
 543 {
 544   BusConnectionData *d;
 545   dbus_bool_t retval;
 546   DBusError error;
 547
 548   d = dbus_new0 (BusConnectionData, 1);
 549
 550   if (d == NULL)
 551     return FALSE;
 552
 553   d->connections = connections;
 554   d->connection = connection;
 555
 556   _dbus_get_current_time (&d->connection_tv_sec,
 557                           &d->connection_tv_usec);
 558
 559   _dbus_assert (connection_data_slot >= 0);
 560
 561   if (!dbus_connection_set_data (connection,
 562                                  connection_data_slot,
 563                                  d, free_connection_data))
 564     {
 565       dbus_free (d);
 566       return FALSE;
 567     }
 568
 569   dbus_connection_set_route_peer_messages (connection, TRUE);
 570
 571   retval = FALSE;
 572
 573   dbus_error_init (&error);
 574   d->selinux_id = bus_selinux_init_connection_id (connection,
 575                                                   &error);
 576   if (dbus_error_is_set (&error))
 577     {
 578       /* This is a bit bogus because we pretend all errors
 579        * are OOM; this is done because we know that in bus.c
 580        * an OOM error disconnects the connection, which is
 581        * the same thing we want on any other error.
 582        */
 583       dbus_error_free (&error);
 584       goto out;
 585     }
 586
 587   if (!dbus_connection_set_watch_functions (connection,
 588                                             add_connection_watch,
 589                                             remove_connection_watch,
 590                                             NULL,
 591                                             connection,
 592                                             NULL))
 593     goto out;
 594
 595   if (!dbus_connection_set_timeout_functions (connection,
 596                                               add_connection_timeout,
 597                                               remove_connection_timeout,
 598                                               NULL,
 599                                               connection, NULL))
 600     goto out;
 601
 602   /* For now we don't need to set a Windows user function because
 603    * there are no policies in the config file controlling what
 604    * Windows users can connect. The default 'same user that owns the
 605    * bus can connect' behavior of DBusConnection is fine on Windows.
 606    */
 607   dbus_connection_set_unix_user_function (connection,
 608                                           allow_unix_user_function,
 609                                           NULL, NULL);
 610
 611   dbus_connection_set_dispatch_status_function (connection,
 612                                                 dispatch_status_function,
 613                                                 bus_context_get_loop (connections->context),
 614                                                 NULL);
 615
 616   d->link_in_connection_list = _dbus_list_alloc_link (connection);
 617   if (d->link_in_connection_list == NULL)
 618     goto out;
 619
 620   /* Setup the connection with the dispatcher */
 621   if (!bus_dispatch_add_connection (connection))
 622     goto out;
 623
 624   if (dbus_connection_get_dispatch_status (connection) != DBUS_DISPATCH_COMPLETE)
 625     {
 626       if (!_dbus_loop_queue_dispatch (bus_context_get_loop (connections->context), connection))
 627         {
 628           bus_dispatch_remove_connection (connection);
 629           goto out;
 630         }
 631     }
 632
 633   _dbus_list_append_link (&connections->incomplete, d->link_in_connection_list);
 634   connections->n_incomplete += 1;
 635
 636   dbus_connection_ref (connection);
 637
 638   /* Note that we might disconnect ourselves here, but it only takes
 639    * effect on return to the main loop. We call this to free up
 640    * expired connections if possible, and to queue the timeout for our
 641    * own expiration.
 642    */
 643   bus_connections_expire_incomplete (connections);
 644
 645   /* And we might also disconnect ourselves here, but again it
 646    * only takes effect on return to main loop.
 647    */
 648   if (connections->n_incomplete >
 649       bus_context_get_max_incomplete_connections (connections->context))
 650     {
 651       _dbus_verbose ("Number of incomplete connections exceeds max, dropping oldest one\n");
 652
 653       _dbus_assert (connections->incomplete != NULL);
 654       /* Disconnect the oldest unauthenticated connection.  FIXME
 655        * would it be more secure to drop a *random* connection?  This
 656        * algorithm seems to mean that if someone can create new
 657        * connections quickly enough, they can keep anyone else from
 658        * completing authentication. But random may or may not really
 659        * help with that, a more elaborate solution might be required.
 660        */
 661       dbus_connection_close (connections->incomplete->data);
 662     }
 663
 664   retval = TRUE;
 665
 666  out:
 667   if (!retval)
 668     {
 669       if (d->selinux_id)
 670         bus_selinux_id_unref (d->selinux_id);
 671       d->selinux_id = NULL;
 672
 673       if (!dbus_connection_set_watch_functions (connection,
 674                                                 NULL, NULL, NULL,
 675                                                 connection,
 676                                                 NULL))
 677         _dbus_assert_not_reached ("setting watch functions to NULL failed");
 678
 679       if (!dbus_connection_set_timeout_functions (connection,
 680                                                   NULL, NULL, NULL,
 681                                                   connection,
 682                                                   NULL))
 683         _dbus_assert_not_reached ("setting timeout functions to NULL failed");
 684
 685       dbus_connection_set_unix_user_function (connection,
 686                                               NULL, NULL, NULL);
 687
 688       dbus_connection_set_windows_user_function (connection,
 689                                                  NULL, NULL, NULL);
 690
 691       dbus_connection_set_dispatch_status_function (connection,
 692                                                     NULL, NULL, NULL);
 693
 694       if (d->link_in_connection_list != NULL)
 695         {
 696           _dbus_assert (d->link_in_connection_list->next == NULL);
 697           _dbus_assert (d->link_in_connection_list->prev == NULL);
 698           _dbus_list_free_link (d->link_in_connection_list);
 699           d->link_in_connection_list = NULL;
 700         }
 701
 702       if (!dbus_connection_set_data (connection,
 703                                      connection_data_slot,
 704                                      NULL, NULL))
 705         _dbus_assert_not_reached ("failed to set connection data to null");
 706
 707       /* "d" has now been freed */
 708     }
 709
 710   return retval;
 711 }
 712
 713 void
 714 bus_connections_expire_incomplete (BusConnections *connections)
 715 {
 716   int next_interval;
 717
 718   next_interval = -1;
 719
 720   if (connections->incomplete != NULL)
 721     {
 722       long tv_sec, tv_usec;
 723       DBusList *link;
 724       int auth_timeout;
 725
 726       _dbus_get_current_time (&tv_sec, &tv_usec);
 727       auth_timeout = bus_context_get_auth_timeout (connections->context);
 728
 729       link = _dbus_list_get_first_link (&connections->incomplete);
 730       while (link != NULL)
 731         {
 732           DBusList *next = _dbus_list_get_next_link (&connections->incomplete, link);
 733           DBusConnection *connection;
 734           BusConnectionData *d;
 735           double elapsed;
 736
 737           connection = link->data;
 738
 739           d = BUS_CONNECTION_DATA (connection);
 740
 741           _dbus_assert (d != NULL);
 742
 743           elapsed = ELAPSED_MILLISECONDS_SINCE (d->connection_tv_sec,
 744                                                 d->connection_tv_usec,
 745                                                 tv_sec, tv_usec);
 746
 747           if (elapsed >= (double) auth_timeout)
 748             {
 749               _dbus_verbose ("Timing out authentication for connection %p\n", connection);
 750               dbus_connection_close (connection);
 751             }
 752           else
 753             {
 754               /* We can end the loop, since the connections are in oldest-first order */
 755               next_interval = ((double)auth_timeout) - elapsed;
 756               _dbus_verbose ("Connection %p authentication expires in %d milliseconds\n",
 757                              connection, next_interval);
 758
 759               break;
 760             }
 761
 762           link = next;
 763         }
 764     }
 765
 766   bus_expire_timeout_set_interval (connections->expire_timeout,
 767                                    next_interval);
 768 }
 769
 770 static dbus_bool_t
 771 expire_incomplete_timeout (void *data)
 772 {
 773   BusConnections *connections = data;
 774
 775   _dbus_verbose ("Running %s\n", _DBUS_FUNCTION_NAME);
 776
 777   /* note that this may remove the timeout */
 778   bus_connections_expire_incomplete (connections);
 779
 780   return TRUE;
 781 }
 782
 783 dbus_bool_t
 784 bus_connection_get_unix_groups  (DBusConnection   *connection,
 785                                  unsigned long   **groups,
 786                                  int              *n_groups,
 787                                  DBusError        *error)
 788 {
 789   BusConnectionData *d;
 790   unsigned long uid;
 791
 792   d = BUS_CONNECTION_DATA (connection);
 793
 794   _dbus_assert (d != NULL);
 795
 796   *groups = NULL;
 797   *n_groups = 0;
 798
 799   if (dbus_connection_get_unix_user (connection, &uid))
 800     {
 801       if (!_dbus_unix_groups_from_uid (uid, groups, n_groups))
 802         {
 803           _dbus_verbose ("Did not get any groups for UID %lu\n",
 804                          uid);
 805           return FALSE;
 806         }
 807       else
 808         {
 809           _dbus_verbose ("Got %d groups for UID %lu\n",
 810                          *n_groups, uid);
 811           return TRUE;
 812         }
 813     }
 814   else
 815     return TRUE; /* successfully got 0 groups */
 816 }
 817
 818 dbus_bool_t
 819 bus_connection_is_in_unix_group (DBusConnection *connection,
 820                                  unsigned long   gid)
 821 {
 822   int i;
 823   unsigned long *group_ids;
 824   int n_group_ids;
 825
 826   if (!bus_connection_get_unix_groups (connection, &group_ids, &n_group_ids,
 827                                        NULL))
 828     return FALSE;
 829
 830   i = 0;
 831   while (i < n_group_ids)
 832     {
 833       if (group_ids[i] == gid)
 834         {
 835           dbus_free (group_ids);
 836           return TRUE;
 837         }
 838       ++i;
 839     }
 840
 841   dbus_free (group_ids);
 842   return FALSE;
 843 }
 844
 845 BusClientPolicy*
 846 bus_connection_get_policy (DBusConnection *connection)
 847 {
 848   BusConnectionData *d;
 849
 850   d = BUS_CONNECTION_DATA (connection);
 851
 852   _dbus_assert (d != NULL);
 853   _dbus_assert (d->policy != NULL);
 854
 855   return d->policy;
 856 }
 857
 858 static dbus_bool_t
 859 foreach_active (BusConnections               *connections,
 860                 BusConnectionForeachFunction  function,
 861                 void                         *data)
 862 {
 863   DBusList *link;
 864
 865   link = _dbus_list_get_first_link (&connections->completed);
 866   while (link != NULL)
 867     {
 868       DBusConnection *connection = link->data;
 869       DBusList *next = _dbus_list_get_next_link (&connections->completed, link);
 870
 871       if (!(* function) (connection, data))
 872         return FALSE;
 873
 874       link = next;
 875     }
 876
 877   return TRUE;
 878 }
 879
 880 static dbus_bool_t
 881 foreach_inactive (BusConnections               *connections,
 882                   BusConnectionForeachFunction  function,
 883                   void                         *data)
 884 {
 885   DBusList *link;
 886
 887   link = _dbus_list_get_first_link (&connections->incomplete);
 888   while (link != NULL)
 889     {
 890       DBusConnection *connection = link->data;
 891       DBusList *next = _dbus_list_get_next_link (&connections->incomplete, link);
 892
 893       if (!(* function) (connection, data))
 894         return FALSE;
 895
 896       link = next;
 897     }
 898
 899   return TRUE;
 900 }
 901
 902 /**
 903  * Calls function on each active connection; if the function returns
 904  * #FALSE, stops iterating. Active connections are authenticated
 905  * and have sent a Hello message.
 906  *
 907  * @param connections the connections object
 908  * @param function the function
 909  * @param data data to pass to it as a second arg
 910  */
 911 void
 912 bus_connections_foreach_active (BusConnections               *connections,
 913                                 BusConnectionForeachFunction  function,
 914                                 void                         *data)
 915 {
 916   foreach_active (connections, function, data);
 917 }
 918
 919 /**
 920  * Calls function on each connection; if the function returns
 921  * #FALSE, stops iterating.
 922  *
 923  * @param connections the connections object
 924  * @param function the function
 925  * @param data data to pass to it as a second arg
 926  */
 927 void
 928 bus_connections_foreach (BusConnections               *connections,
 929                          BusConnectionForeachFunction  function,
 930                          void                         *data)
 931 {
 932   if (!foreach_active (connections, function, data))
 933     return;
 934
 935   foreach_inactive (connections, function, data);
 936 }
 937
 938 BusContext*
 939 bus_connections_get_context (BusConnections *connections)
 940 {
 941   return connections->context;
 942 }
 943
 944 /*
 945  * This is used to avoid covering the same connection twice when
 946  * traversing connections. Note that it assumes we will
 947  * bus_connection_mark_stamp() each connection at least once per
 948  * INT_MAX increments of the global stamp, or wraparound would break
 949  * things.
 950  */
 951 void
 952 bus_connections_increment_stamp (BusConnections *connections)
 953 {
 954   connections->stamp += 1;
 955 }
 956
 957 /* Mark connection with current stamp, return TRUE if it
 958  * didn't already have that stamp
 959  */
 960 dbus_bool_t
 961 bus_connection_mark_stamp (DBusConnection *connection)
 962 {
 963   BusConnectionData *d;
 964
 965   d = BUS_CONNECTION_DATA (connection);
 966
 967   _dbus_assert (d != NULL);
 968
 969   if (d->stamp == d->connections->stamp)
 970     return FALSE;
 971   else
 972     {
 973       d->stamp = d->connections->stamp;
 974       return TRUE;
 975     }
 976 }
 977
 978 BusContext*
 979 bus_connection_get_context (DBusConnection *connection)
 980 {
 981   BusConnectionData *d;
 982
 983   d = BUS_CONNECTION_DATA (connection);
 984
 985   _dbus_assert (d != NULL);
 986
 987   return d->connections->context;
 988 }
 989
 990 BusConnections*
 991 bus_connection_get_connections (DBusConnection *connection)
 992 {
 993   BusConnectionData *d;
 994
 995   d = BUS_CONNECTION_DATA (connection);
 996
 997   _dbus_assert (d != NULL);
 998
 999   return d->connections;
1000 }
1001
1002 BusRegistry*
1003 bus_connection_get_registry (DBusConnection *connection)
1004 {
1005   BusConnectionData *d;
1006
1007   d = BUS_CONNECTION_DATA (connection);
1008
1009   _dbus_assert (d != NULL);
1010
1011   return bus_context_get_registry (d->connections->context);
1012 }
1013
1014 BusActivation*
1015 bus_connection_get_activation (DBusConnection *connection)
1016 {
1017   BusConnectionData *d;
1018
1019   d = BUS_CONNECTION_DATA (connection);
1020
1021   _dbus_assert (d != NULL);
1022
1023   return bus_context_get_activation (d->connections->context);
1024 }
1025
1026 BusMatchmaker*
1027 bus_connection_get_matchmaker (DBusConnection *connection)
1028 {
1029   BusConnectionData *d;
1030
1031   d = BUS_CONNECTION_DATA (connection);
1032
1033   _dbus_assert (d != NULL);
1034
1035   return bus_context_get_matchmaker (d->connections->context);
1036 }
1037
1038 BusSELinuxID*
1039 bus_connection_get_selinux_id (DBusConnection *connection)
1040 {
1041   BusConnectionData *d;
1042
1043   d = BUS_CONNECTION_DATA (connection);
1044
1045   _dbus_assert (d != NULL);
1046
1047   return d->selinux_id;
1048 }
1049
1050 /**
1051  * Checks whether the connection is registered with the message bus.
1052  *
1053  * @param connection the connection
1054  * @returns #TRUE if we're an active message bus participant
1055  */
1056 dbus_bool_t
1057 bus_connection_is_active (DBusConnection *connection)
1058 {
1059   BusConnectionData *d;
1060
1061   d = BUS_CONNECTION_DATA (connection);
1062
1063   return d != NULL && d->name != NULL;
1064 }
1065
1066 dbus_bool_t
1067 bus_connection_preallocate_oom_error (DBusConnection *connection)
1068 {
1069   DBusMessage *message;
1070   DBusPreallocatedSend *preallocated;
1071   BusConnectionData *d;
1072
1073   d = BUS_CONNECTION_DATA (connection);
1074
1075   _dbus_assert (d != NULL);
1076
1077   if (d->oom_preallocated != NULL)
1078     return TRUE;
1079
1080   preallocated = dbus_connection_preallocate_send (connection);
1081   if (preallocated == NULL)
1082     return FALSE;
1083
1084   message = dbus_message_new (DBUS_MESSAGE_TYPE_ERROR);
1085
1086   if (message == NULL)
1087     {
1088       dbus_connection_free_preallocated_send (connection, preallocated);
1089       return FALSE;
1090     }
1091
1092   /* d->name may be NULL, but that is OK */
1093   if (!dbus_message_set_error_name (message, DBUS_ERROR_NO_MEMORY) ||
1094       !dbus_message_set_destination (message, d->name) ||
1095       !dbus_message_set_sender (message,
1096                                 DBUS_SERVICE_DBUS))
1097     {
1098       dbus_connection_free_preallocated_send (connection, preallocated);
1099       dbus_message_unref (message);
1100       return FALSE;
1101     }
1102
1103   /* set reply serial to placeholder value just so space is already allocated
1104    * for it.
1105    */
1106   if (!dbus_message_set_reply_serial (message, 14))
1107     {
1108       dbus_connection_free_preallocated_send (connection, preallocated);
1109       dbus_message_unref (message);
1110       return FALSE;
1111     }
1112
1113   d->oom_message = message;
1114   d->oom_preallocated = preallocated;
1115
1116   return TRUE;
1117 }
1118
1119 void
1120 bus_connection_send_oom_error (DBusConnection *connection,
1121                                DBusMessage    *in_reply_to)
1122 {
1123   BusConnectionData *d;
1124
1125   d = BUS_CONNECTION_DATA (connection);
1126
1127   _dbus_assert (d != NULL);
1128   _dbus_assert (d->oom_message != NULL);
1129
1130   /* should always succeed since we set it to a placeholder earlier */
1131   if (!dbus_message_set_reply_serial (d->oom_message,
1132                                       dbus_message_get_serial (in_reply_to)))
1133     _dbus_assert_not_reached ("Failed to set reply serial for preallocated oom message");
1134
1135   _dbus_assert (dbus_message_get_sender (d->oom_message) != NULL);
1136
1137   dbus_connection_send_preallocated (connection, d->oom_preallocated,
1138                                      d->oom_message, NULL);
1139
1140   dbus_message_unref (d->oom_message);
1141   d->oom_message = NULL;
1142   d->oom_preallocated = NULL;
1143 }
1144
1145 void
1146 bus_connection_add_match_rule_link (DBusConnection *connection,
1147                                     DBusList       *link)
1148 {
1149   BusConnectionData *d;
1150
1151   d = BUS_CONNECTION_DATA (connection);
1152   _dbus_assert (d != NULL);
1153
1154   _dbus_list_append_link (&d->match_rules, link);
1155
1156   d->n_match_rules += 1;
1157 }
1158
1159 dbus_bool_t
1160 bus_connection_add_match_rule (DBusConnection *connection,
1161                                BusMatchRule   *rule)
1162 {
1163     DBusList *link;
1164
1165   link = _dbus_list_alloc_link (rule);
1166
1167   if (link == NULL)
1168     return FALSE;
1169
1170   bus_connection_add_match_rule_link (connection, link);
1171
1172   return TRUE;
1173 }
1174
1175 void
1176 bus_connection_remove_match_rule (DBusConnection *connection,
1177                                   BusMatchRule   *rule)
1178 {
1179   BusConnectionData *d;
1180
1181   d = BUS_CONNECTION_DATA (connection);
1182   _dbus_assert (d != NULL);
1183
1184   _dbus_list_remove_last (&d->match_rules, rule);
1185
1186   d->n_match_rules -= 1;
1187   _dbus_assert (d->n_match_rules >= 0);
1188 }
1189
1190 int
1191 bus_connection_get_n_match_rules (DBusConnection *connection)
1192 {
1193   BusConnectionData *d;
1194
1195   d = BUS_CONNECTION_DATA (connection);
1196   _dbus_assert (d != NULL);
1197
1198   return d->n_match_rules;
1199 }
1200
1201 void
1202 bus_connection_add_owned_service_link (DBusConnection *connection,
1203                                        DBusList       *link)
1204 {
1205   BusConnectionData *d;
1206
1207   d = BUS_CONNECTION_DATA (connection);
1208   _dbus_assert (d != NULL);
1209
1210   _dbus_list_append_link (&d->services_owned, link);
1211
1212   d->n_services_owned += 1;
1213 }
1214
1215 dbus_bool_t
1216 bus_connection_add_owned_service (DBusConnection *connection,
1217                                   BusService     *service)
1218 {
1219   DBusList *link;
1220
1221   link = _dbus_list_alloc_link (service);
1222
1223   if (link == NULL)
1224     return FALSE;
1225
1226   bus_connection_add_owned_service_link (connection, link);
1227
1228   return TRUE;
1229 }
1230
1231 void
1232 bus_connection_remove_owned_service (DBusConnection *connection,
1233                                      BusService     *service)
1234 {
1235   BusConnectionData *d;
1236
1237   d = BUS_CONNECTION_DATA (connection);
1238   _dbus_assert (d != NULL);
1239
1240   _dbus_list_remove_last (&d->services_owned, service);
1241
1242   d->n_services_owned -= 1;
1243   _dbus_assert (d->n_services_owned >= 0);
1244 }
1245
1246 int
1247 bus_connection_get_n_services_owned (DBusConnection *connection)
1248 {
1249   BusConnectionData *d;
1250
1251   d = BUS_CONNECTION_DATA (connection);
1252   _dbus_assert (d != NULL);
1253
1254   return d->n_services_owned;
1255 }
1256
1257 dbus_bool_t
1258 bus_connection_complete (DBusConnection   *connection,
1259                          const DBusString *name,
1260                          DBusError        *error)
1261 {
1262   BusConnectionData *d;
1263   unsigned long uid;
1264
1265   d = BUS_CONNECTION_DATA (connection);
1266   _dbus_assert (d != NULL);
1267   _dbus_assert (d->name == NULL);
1268   _dbus_assert (d->policy == NULL);
1269
1270   _dbus_assert (!bus_connection_is_active (connection));
1271
1272   if (!_dbus_string_copy_data (name, &d->name))
1273     {
1274       BUS_SET_OOM (error);
1275       return FALSE;
1276     }
1277
1278   _dbus_assert (d->name != NULL);
1279
1280   _dbus_verbose ("Name %s assigned to %p\n", d->name, connection);
1281
1282   d->policy = bus_context_create_client_policy (d->connections->context,
1283                                                 connection,
1284                                                 error);
1285
1286   /* we may have a NULL policy on OOM or error getting list of
1287    * groups for a user. In the latter case we don't handle it so
1288    * well currently, as it will just keep failing over and over.
1289    */
1290
1291   if (d->policy == NULL)
1292     {
1293       _dbus_verbose ("Failed to create security policy for connection %p\n",
1294                      connection);
1295       _DBUS_ASSERT_ERROR_IS_SET (error);
1296       dbus_free (d->name);
1297       d->name = NULL;
1298       return FALSE;
1299     }
1300
1301   if (dbus_connection_get_unix_user (connection, &uid))
1302     {
1303       if (!adjust_connections_for_uid (d->connections,
1304                                        uid, 1))
1305         {
1306           BUS_SET_OOM (error);
1307           dbus_free (d->name);
1308           d->name = NULL;
1309           return FALSE;
1310         }
1311     }
1312
1313   /* Now the connection is active, move it between lists */
1314   _dbus_list_unlink (&d->connections->incomplete,
1315                      d->link_in_connection_list);
1316   d->connections->n_incomplete -= 1;
1317   _dbus_list_append_link (&d->connections->completed,
1318                           d->link_in_connection_list);
1319   d->connections->n_completed += 1;
1320
1321   _dbus_assert (d->connections->n_incomplete >= 0);
1322   _dbus_assert (d->connections->n_completed > 0);
1323
1324   /* See if we can remove the timeout */
1325   bus_connections_expire_incomplete (d->connections);
1326
1327   _dbus_assert (bus_connection_is_active (connection));
1328
1329   return TRUE;
1330 }
1331
1332 const char *
1333 bus_connection_get_name (DBusConnection *connection)
1334 {
1335   BusConnectionData *d;
1336
1337   d = BUS_CONNECTION_DATA (connection);
1338   _dbus_assert (d != NULL);
1339
1340   return d->name;
1341 }
1342
1343 /**
1344  * Check whether completing the passed-in connection would
1345  * exceed limits, and if so set error and return #FALSE
1346  */
1347 dbus_bool_t
1348 bus_connections_check_limits (BusConnections  *connections,
1349                               DBusConnection  *requesting_completion,
1350                               DBusError       *error)
1351 {
1352   BusConnectionData *d;
1353   unsigned long uid;
1354
1355   d = BUS_CONNECTION_DATA (requesting_completion);
1356   _dbus_assert (d != NULL);
1357
1358   _dbus_assert (d->name == NULL);
1359
1360   if (connections->n_completed >=
1361       bus_context_get_max_completed_connections (connections->context))
1362     {
1363       dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
1364                       "The maximum number of active connections has been reached");
1365       return FALSE;
1366     }
1367
1368   if (dbus_connection_get_unix_user (requesting_completion, &uid))
1369     {
1370       if (get_connections_for_uid (connections, uid) >=
1371           bus_context_get_max_connections_per_user (connections->context))
1372         {
1373           dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
1374                           "The maximum number of active connections for UID %lu has been reached",
1375                           uid);
1376           return FALSE;
1377         }
1378     }
1379
1380   return TRUE;
1381 }
1382
1383 static void
1384 bus_pending_reply_free (BusPendingReply *pending)
1385 {
1386   _dbus_verbose ("Freeing pending reply %p, replier %p receiver %p serial %u\n",
1387                  pending,
1388                  pending->will_send_reply,
1389                  pending->will_get_reply,
1390                  pending->reply_serial);
1391
1392   dbus_free (pending);
1393 }
1394
1395 static dbus_bool_t
1396 bus_pending_reply_send_no_reply (BusConnections  *connections,
1397                                  BusTransaction  *transaction,
1398                                  BusPendingReply *pending)
1399 {
1400   DBusMessage *message;
1401   DBusMessageIter iter;
1402   dbus_bool_t retval;
1403   const char *errmsg;
1404
1405   retval = FALSE;
1406
1407   message = dbus_message_new (DBUS_MESSAGE_TYPE_ERROR);
1408   if (message == NULL)
1409     return FALSE;
1410
1411   dbus_message_set_no_reply (message, TRUE);
1412
1413   if (!dbus_message_set_reply_serial (message,
1414                                       pending->reply_serial))
1415     goto out;
1416
1417   if (!dbus_message_set_error_name (message,
1418                                     DBUS_ERROR_NO_REPLY))
1419     goto out;
1420
1421   errmsg = "Message did not receive a reply (timeout by message bus)";
1422   dbus_message_iter_init_append (message, &iter);
1423   if (!dbus_message_iter_append_basic (&iter, DBUS_TYPE_STRING, &errmsg))
1424     goto out;
1425
1426   if (!bus_transaction_send_from_driver (transaction, pending->will_get_reply,
1427                                          message))
1428     goto out;
1429
1430   retval = TRUE;
1431
1432  out:
1433   dbus_message_unref (message);
1434   return retval;
1435 }
1436
1437 static dbus_bool_t
1438 bus_pending_reply_expired (BusExpireList *list,
1439                            DBusList      *link,
1440                            void          *data)
1441 {
1442   BusPendingReply *pending = link->data;
1443   BusConnections *connections = data;
1444   BusTransaction *transaction;
1445
1446   /* No reply is forthcoming. So nuke it if we can. If not,
1447    * leave it in the list to try expiring again later when we
1448    * get more memory.
1449    */
1450
1451   _dbus_verbose ("Expiring pending reply %p, replier %p receiver %p serial %u\n",
1452                  pending,
1453                  pending->will_send_reply,
1454                  pending->will_get_reply,
1455                  pending->reply_serial);
1456
1457   transaction = bus_transaction_new (connections->context);
1458   if (transaction == NULL)
1459     return FALSE;
1460
1461   if (!bus_pending_reply_send_no_reply (connections,
1462                                         transaction,
1463                                         pending))
1464     {
1465       bus_transaction_cancel_and_free (transaction);
1466       return FALSE;
1467     }
1468
1469   _dbus_list_remove_link (&connections->pending_replies->items,
1470                           link);
1471   bus_pending_reply_free (pending);
1472   bus_transaction_execute_and_free (transaction);
1473
1474   return TRUE;
1475 }
1476
1477 static void
1478 bus_connection_drop_pending_replies (BusConnections  *connections,
1479                                      DBusConnection  *connection)
1480 {
1481   /* The DBusConnection is almost 100% finalized here, so you can't
1482    * do anything with it except check for pointer equality
1483    */
1484   DBusList *link;
1485
1486   _dbus_verbose ("Dropping pending replies that involve connection %p\n",
1487                  connection);
1488
1489   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1490   while (link != NULL)
1491     {
1492       DBusList *next;
1493       BusPendingReply *pending;
1494
1495       next = _dbus_list_get_next_link (&connections->pending_replies->items,
1496                                        link);
1497       pending = link->data;
1498
1499       if (pending->will_get_reply == connection)
1500         {
1501           /* We don't need to track this pending reply anymore */
1502
1503           _dbus_verbose ("Dropping pending reply %p, replier %p receiver %p serial %u\n",
1504                          pending,
1505                          pending->will_send_reply,
1506                          pending->will_get_reply,
1507                          pending->reply_serial);
1508
1509           _dbus_list_remove_link (&connections->pending_replies->items,
1510                                   link);
1511           bus_pending_reply_free (pending);
1512         }
1513       else if (pending->will_send_reply == connection)
1514         {
1515           /* The reply isn't going to be sent, so set things
1516            * up so it will be expired right away
1517            */
1518           _dbus_verbose ("Will expire pending reply %p, replier %p receiver %p serial %u\n",
1519                          pending,
1520                          pending->will_send_reply,
1521                          pending->will_get_reply,
1522                          pending->reply_serial);
1523
1524           pending->will_send_reply = NULL;
1525           pending->expire_item.added_tv_sec = 0;
1526           pending->expire_item.added_tv_usec = 0;
1527
1528           bus_expire_timeout_set_interval (connections->pending_replies->timeout,
1529                                            0);
1530         }
1531
1532       link = next;
1533     }
1534 }
1535
1536
1537 typedef struct
1538 {
1539   BusPendingReply *pending;
1540   BusConnections  *connections;
1541 } CancelPendingReplyData;
1542
1543 static void
1544 cancel_pending_reply (void *data)
1545 {
1546   CancelPendingReplyData *d = data;
1547
1548   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1549
1550   if (!_dbus_list_remove (&d->connections->pending_replies->items,
1551                           d->pending))
1552     _dbus_assert_not_reached ("pending reply did not exist to be cancelled");
1553
1554   bus_pending_reply_free (d->pending); /* since it's been cancelled */
1555 }
1556
1557 static void
1558 cancel_pending_reply_data_free (void *data)
1559 {
1560   CancelPendingReplyData *d = data;
1561
1562   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1563
1564   /* d->pending should be either freed or still
1565    * in the list of pending replies (owned by someone
1566    * else)
1567    */
1568
1569   dbus_free (d);
1570 }
1571
1572 /*
1573  * Record that a reply is allowed; return TRUE on success.
1574  */
1575 dbus_bool_t
1576 bus_connections_expect_reply (BusConnections  *connections,
1577                               BusTransaction  *transaction,
1578                               DBusConnection  *will_get_reply,
1579                               DBusConnection  *will_send_reply,
1580                               DBusMessage     *reply_to_this,
1581                               DBusError       *error)
1582 {
1583   BusPendingReply *pending;
1584   dbus_uint32_t reply_serial;
1585   DBusList *link;
1586   CancelPendingReplyData *cprd;
1587   int count;
1588
1589   _dbus_assert (will_get_reply != NULL);
1590   _dbus_assert (will_send_reply != NULL);
1591   _dbus_assert (reply_to_this != NULL);
1592
1593   if (dbus_message_get_no_reply (reply_to_this))
1594     return TRUE; /* we won't allow a reply, since client doesn't care for one. */
1595
1596   reply_serial = dbus_message_get_serial (reply_to_this);
1597
1598   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1599   count = 0;
1600   while (link != NULL)
1601     {
1602       pending = link->data;
1603
1604       if (pending->reply_serial == reply_serial &&
1605           pending->will_get_reply == will_get_reply &&
1606           pending->will_send_reply == will_send_reply)
1607         {
1608           dbus_set_error (error, DBUS_ERROR_ACCESS_DENIED,
1609                           "Message has the same reply serial as a currently-outstanding existing method call");
1610           return FALSE;
1611         }
1612
1613       link = _dbus_list_get_next_link (&connections->pending_replies->items,
1614                                        link);
1615       if (pending->will_get_reply == will_get_reply)
1616         ++count;
1617     }
1618
1619   if (count >=
1620       bus_context_get_max_replies_per_connection (connections->context))
1621     {
1622       dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
1623                       "The maximum number of pending replies per connection has been reached");
1624       return FALSE;
1625     }
1626
1627   pending = dbus_new0 (BusPendingReply, 1);
1628   if (pending == NULL)
1629     {
1630       BUS_SET_OOM (error);
1631       return FALSE;
1632     }
1633
1634 #ifdef DBUS_ENABLE_VERBOSE_MODE
1635   /* so we can see a not-yet-added pending reply */
1636   pending->expire_item.added_tv_sec = 1;
1637   pending->expire_item.added_tv_usec = 1;
1638 #endif
1639
1640   pending->will_get_reply = will_get_reply;
1641   pending->will_send_reply = will_send_reply;
1642   pending->reply_serial = reply_serial;
1643
1644   cprd = dbus_new0 (CancelPendingReplyData, 1);
1645   if (cprd == NULL)
1646     {
1647       BUS_SET_OOM (error);
1648       bus_pending_reply_free (pending);
1649       return FALSE;
1650     }
1651
1652   if (!_dbus_list_prepend (&connections->pending_replies->items,
1653                            pending))
1654     {
1655       BUS_SET_OOM (error);
1656       dbus_free (cprd);
1657       bus_pending_reply_free (pending);
1658       return FALSE;
1659     }
1660
1661   if (!bus_transaction_add_cancel_hook (transaction,
1662                                         cancel_pending_reply,
1663                                         cprd,
1664                                         cancel_pending_reply_data_free))
1665     {
1666       BUS_SET_OOM (error);
1667       _dbus_list_remove (&connections->pending_replies->items, pending);
1668       dbus_free (cprd);
1669       bus_pending_reply_free (pending);
1670       return FALSE;
1671     }
1672
1673   cprd->pending = pending;
1674   cprd->connections = connections;
1675
1676   _dbus_get_current_time (&pending->expire_item.added_tv_sec,
1677                           &pending->expire_item.added_tv_usec);
1678
1679   _dbus_verbose ("Added pending reply %p, replier %p receiver %p serial %u\n",
1680                  pending,
1681                  pending->will_send_reply,
1682                  pending->will_get_reply,
1683                  pending->reply_serial);
1684
1685   return TRUE;
1686 }
1687
1688 typedef struct
1689 {
1690   DBusList        *link;
1691   BusConnections  *connections;
1692 } CheckPendingReplyData;
1693
1694 static void
1695 cancel_check_pending_reply (void *data)
1696 {
1697   CheckPendingReplyData *d = data;
1698
1699   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1700
1701   _dbus_list_prepend_link (&d->connections->pending_replies->items,
1702                            d->link);
1703   d->link = NULL;
1704 }
1705
1706 static void
1707 check_pending_reply_data_free (void *data)
1708 {
1709   CheckPendingReplyData *d = data;
1710
1711   _dbus_verbose ("%s: d = %p\n", _DBUS_FUNCTION_NAME, d);
1712
1713   if (d->link != NULL)
1714     {
1715       BusPendingReply *pending = d->link->data;
1716
1717       _dbus_assert (_dbus_list_find_last (&d->connections->pending_replies->items,
1718                                           pending) == NULL);
1719
1720       bus_pending_reply_free (pending);
1721       _dbus_list_free_link (d->link);
1722     }
1723
1724   dbus_free (d);
1725 }
1726
1727 /*
1728  * Check whether a reply is allowed, remove BusPendingReply
1729  * if so, return TRUE if so.
1730  */
1731 dbus_bool_t
1732 bus_connections_check_reply (BusConnections *connections,
1733                              BusTransaction *transaction,
1734                              DBusConnection *sending_reply,
1735                              DBusConnection *receiving_reply,
1736                              DBusMessage    *reply,
1737                              DBusError      *error)
1738 {
1739   CheckPendingReplyData *cprd;
1740   DBusList *link;
1741   dbus_uint32_t reply_serial;
1742
1743   _dbus_assert (sending_reply != NULL);
1744   _dbus_assert (receiving_reply != NULL);
1745
1746   reply_serial = dbus_message_get_reply_serial (reply);
1747
1748   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1749   while (link != NULL)
1750     {
1751       BusPendingReply *pending = link->data;
1752
1753       if (pending->reply_serial == reply_serial &&
1754           pending->will_get_reply == receiving_reply &&
1755           pending->will_send_reply == sending_reply)
1756         {
1757           _dbus_verbose ("Found pending reply with serial %u\n", reply_serial);
1758           break;
1759         }
1760
1761       link = _dbus_list_get_next_link (&connections->pending_replies->items,
1762                                        link);
1763     }
1764
1765   if (link == NULL)
1766     {
1767       _dbus_verbose ("No pending reply expected\n");
1768
1769       return FALSE;
1770     }
1771
1772   cprd = dbus_new0 (CheckPendingReplyData, 1);
1773   if (cprd == NULL)
1774     {
1775       BUS_SET_OOM (error);
1776       return FALSE;
1777     }
1778
1779   if (!bus_transaction_add_cancel_hook (transaction,
1780                                         cancel_check_pending_reply,
1781                                         cprd,
1782                                         check_pending_reply_data_free))
1783     {
1784       BUS_SET_OOM (error);
1785       dbus_free (cprd);
1786       return FALSE;
1787     }
1788
1789   cprd->link = link;
1790   cprd->connections = connections;
1791
1792   _dbus_list_unlink (&connections->pending_replies->items,
1793                      link);
1794
1795   _dbus_assert (_dbus_list_find_last (&connections->pending_replies->items,
1796                                       link->data) == NULL);
1797
1798   return TRUE;
1799 }
1800
1801 /*
1802  * Transactions
1803  *
1804  * Note that this is fairly fragile; in particular, don't try to use
1805  * one transaction across any main loop iterations.
1806  */
1807
1808 typedef struct
1809 {
1810   BusTransaction *transaction;
1811   DBusMessage    *message;
1812   DBusPreallocatedSend *preallocated;
1813 } MessageToSend;
1814
1815 typedef struct
1816 {
1817   BusTransactionCancelFunction cancel_function;
1818   DBusFreeFunction free_data_function;
1819   void *data;
1820 } CancelHook;
1821
1822 struct BusTransaction
1823 {
1824   DBusList *connections;
1825   BusContext *context;
1826   DBusList *cancel_hooks;
1827 };
1828
1829 static void
1830 message_to_send_free (DBusConnection *connection,
1831                       MessageToSend  *to_send)
1832 {
1833   if (to_send->message)
1834     dbus_message_unref (to_send->message);
1835
1836   if (to_send->preallocated)
1837     dbus_connection_free_preallocated_send (connection, to_send->preallocated);
1838
1839   dbus_free (to_send);
1840 }
1841
1842 static void
1843 cancel_hook_cancel (void *element,
1844                     void *data)
1845 {
1846   CancelHook *ch = element;
1847
1848   _dbus_verbose ("Running transaction cancel hook\n");
1849
1850   if (ch->cancel_function)
1851     (* ch->cancel_function) (ch->data);
1852 }
1853
1854 static void
1855 cancel_hook_free (void *element,
1856                   void *data)
1857 {
1858   CancelHook *ch = element;
1859
1860   if (ch->free_data_function)
1861     (* ch->free_data_function) (ch->data);
1862
1863   dbus_free (ch);
1864 }
1865
1866 static void
1867 free_cancel_hooks (BusTransaction *transaction)
1868 {
1869   _dbus_list_foreach (&transaction->cancel_hooks,
1870                       cancel_hook_free, NULL);
1871
1872   _dbus_list_clear (&transaction->cancel_hooks);
1873 }
1874
1875 BusTransaction*
1876 bus_transaction_new (BusContext *context)
1877 {
1878   BusTransaction *transaction;
1879
1880   transaction = dbus_new0 (BusTransaction, 1);
1881   if (transaction == NULL)
1882     return NULL;
1883
1884   transaction->context = context;
1885
1886   return transaction;
1887 }
1888
1889 BusContext*
1890 bus_transaction_get_context (BusTransaction  *transaction)
1891 {
1892   return transaction->context;
1893 }
1894
1895 BusConnections*
1896 bus_transaction_get_connections (BusTransaction  *transaction)
1897 {
1898   return bus_context_get_connections (transaction->context);
1899 }
1900
1901 dbus_bool_t
1902 bus_transaction_send_from_driver (BusTransaction *transaction,
1903                                   DBusConnection *connection,
1904                                   DBusMessage    *message)
1905 {
1906   /* We have to set the sender to the driver, and have
1907    * to check security policy since it was not done in
1908    * dispatch.c
1909    */
1910   _dbus_verbose ("Sending %s %s %s from driver\n",
1911                  dbus_message_get_interface (message) ?
1912                  dbus_message_get_interface (message) : "(no interface)",
1913                  dbus_message_get_member (message) ?
1914                  dbus_message_get_member (message) : "(no member)",
1915                  dbus_message_get_error_name (message) ?
1916                  dbus_message_get_error_name (message) : "(no error name)");
1917
1918   if (!dbus_message_set_sender (message, DBUS_SERVICE_DBUS))
1919     return FALSE;
1920
1921   if (bus_connection_is_active (connection))
1922     {
1923       if (!dbus_message_set_destination (message,
1924                                          bus_connection_get_name (connection)))
1925         return FALSE;
1926     }
1927
1928   /* bus driver never wants a reply */
1929   dbus_message_set_no_reply (message, TRUE);
1930
1931   /* If security policy doesn't allow the message, we silently
1932    * eat it; the driver doesn't care about getting a reply.
1933    */
1934   if (!bus_context_check_security_policy (bus_transaction_get_context (transaction),
1935                                           transaction,
1936                                           NULL, connection, connection, message, NULL))
1937     return TRUE;
1938
1939   return bus_transaction_send (transaction, connection, message);
1940 }
1941
1942 dbus_bool_t
1943 bus_transaction_send (BusTransaction *transaction,
1944                       DBusConnection *connection,
1945                       DBusMessage    *message)
1946 {
1947   MessageToSend *to_send;
1948   BusConnectionData *d;
1949   DBusList *link;
1950
1951   _dbus_verbose ("  trying to add %s interface=%s member=%s error=%s to transaction%s\n",
1952                  dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_ERROR ? "error" :
1953                  dbus_message_get_reply_serial (message) != 0 ? "reply" :
1954                  "message",
1955                  dbus_message_get_interface (message) ?
1956                  dbus_message_get_interface (message) : "(unset)",
1957                  dbus_message_get_member (message) ?
1958                  dbus_message_get_member (message) : "(unset)",
1959                  dbus_message_get_error_name (message) ?
1960                  dbus_message_get_error_name (message) : "(unset)",
1961                  dbus_connection_get_is_connected (connection) ?
1962                  "" : " (disconnected)");
1963
1964   _dbus_assert (dbus_message_get_sender (message) != NULL);
1965
1966   if (!dbus_connection_get_is_connected (connection))
1967     return TRUE; /* silently ignore disconnected connections */
1968
1969   d = BUS_CONNECTION_DATA (connection);
1970   _dbus_assert (d != NULL);
1971
1972   to_send = dbus_new (MessageToSend, 1);
1973   if (to_send == NULL)
1974     {
1975       return FALSE;
1976     }
1977
1978   to_send->preallocated = dbus_connection_preallocate_send (connection);
1979   if (to_send->preallocated == NULL)
1980     {
1981       dbus_free (to_send);
1982       return FALSE;
1983     }
1984
1985   dbus_message_ref (message);
1986   to_send->message = message;
1987   to_send->transaction = transaction;
1988
1989   _dbus_verbose ("about to prepend message\n");
1990
1991   if (!_dbus_list_prepend (&d->transaction_messages, to_send))
1992     {
1993       message_to_send_free (connection, to_send);
1994       return FALSE;
1995     }
1996
1997   _dbus_verbose ("prepended message\n");
1998
1999   /* See if we already had this connection in the list
2000    * for this transaction. If we have a pending message,
2001    * then we should already be in transaction->connections
2002    */
2003   link = _dbus_list_get_first_link (&d->transaction_messages);
2004   _dbus_assert (link->data == to_send);
2005   link = _dbus_list_get_next_link (&d->transaction_messages, link);
2006   while (link != NULL)
2007     {
2008       MessageToSend *m = link->data;
2009       DBusList *next = _dbus_list_get_next_link (&d->transaction_messages, link);
2010
2011       if (m->transaction == transaction)
2012         break;
2013
2014       link = next;
2015     }
2016
2017   if (link == NULL)
2018     {
2019       if (!_dbus_list_prepend (&transaction->connections, connection))
2020         {
2021           _dbus_list_remove (&d->transaction_messages, to_send);
2022           message_to_send_free (connection, to_send);
2023           return FALSE;
2024         }
2025     }
2026
2027   return TRUE;
2028 }
2029
2030 static void
2031 connection_cancel_transaction (DBusConnection *connection,
2032                                BusTransaction *transaction)
2033 {
2034   DBusList *link;
2035   BusConnectionData *d;
2036
2037   d = BUS_CONNECTION_DATA (connection);
2038   _dbus_assert (d != NULL);
2039
2040   link = _dbus_list_get_first_link (&d->transaction_messages);
2041   while (link != NULL)
2042     {
2043       MessageToSend *m = link->data;
2044       DBusList *next = _dbus_list_get_next_link (&d->transaction_messages, link);
2045
2046       if (m->transaction == transaction)
2047         {
2048           _dbus_list_remove_link (&d->transaction_messages,
2049                                   link);
2050
2051           message_to_send_free (connection, m);
2052         }
2053
2054       link = next;
2055     }
2056 }
2057
2058 void
2059 bus_transaction_cancel_and_free (BusTransaction *transaction)
2060 {
2061   DBusConnection *connection;
2062
2063   _dbus_verbose ("TRANSACTION: cancelled\n");
2064
2065   while ((connection = _dbus_list_pop_first (&transaction->connections)))
2066     connection_cancel_transaction (connection, transaction);
2067
2068   _dbus_assert (transaction->connections == NULL);
2069
2070   _dbus_list_foreach (&transaction->cancel_hooks,
2071                       cancel_hook_cancel, NULL);
2072
2073   free_cancel_hooks (transaction);
2074
2075   dbus_free (transaction);
2076 }
2077
2078 static void
2079 connection_execute_transaction (DBusConnection *connection,
2080                                 BusTransaction *transaction)
2081 {
2082   DBusList *link;
2083   BusConnectionData *d;
2084
2085   d = BUS_CONNECTION_DATA (connection);
2086   _dbus_assert (d != NULL);
2087
2088   /* Send the queue in order (FIFO) */
2089   link = _dbus_list_get_last_link (&d->transaction_messages);
2090   while (link != NULL)
2091     {
2092       MessageToSend *m = link->data;
2093       DBusList *prev = _dbus_list_get_prev_link (&d->transaction_messages, link);
2094
2095       if (m->transaction == transaction)
2096         {
2097           _dbus_list_remove_link (&d->transaction_messages,
2098                                   link);
2099
2100           _dbus_assert (dbus_message_get_sender (m->message) != NULL);
2101
2102           dbus_connection_send_preallocated (connection,
2103                                              m->preallocated,
2104                                              m->message,
2105                                              NULL);
2106
2107           m->preallocated = NULL; /* so we don't double-free it */
2108
2109           message_to_send_free (connection, m);
2110         }
2111
2112       link = prev;
2113     }
2114 }
2115
2116 void
2117 bus_transaction_execute_and_free (BusTransaction *transaction)
2118 {
2119   /* For each connection in transaction->connections
2120    * send the messages
2121    */
2122   DBusConnection *connection;
2123
2124   _dbus_verbose ("TRANSACTION: executing\n");
2125
2126   while ((connection = _dbus_list_pop_first (&transaction->connections)))
2127     connection_execute_transaction (connection, transaction);
2128
2129   _dbus_assert (transaction->connections == NULL);
2130
2131   free_cancel_hooks (transaction);
2132
2133   dbus_free (transaction);
2134 }
2135
2136 static void
2137 bus_connection_remove_transactions (DBusConnection *connection)
2138 {
2139   MessageToSend *to_send;
2140   BusConnectionData *d;
2141
2142   d = BUS_CONNECTION_DATA (connection);
2143   _dbus_assert (d != NULL);
2144
2145   while ((to_send = _dbus_list_get_first (&d->transaction_messages)))
2146     {
2147       /* only has an effect for the first MessageToSend listing this transaction */
2148       _dbus_list_remove (&to_send->transaction->connections,
2149                          connection);
2150
2151       _dbus_list_remove (&d->transaction_messages, to_send);
2152       message_to_send_free (connection, to_send);
2153     }
2154 }
2155
2156 /**
2157  * Converts the DBusError to a message reply
2158  */
2159 dbus_bool_t
2160 bus_transaction_send_error_reply (BusTransaction  *transaction,
2161                                   DBusConnection  *connection,
2162                                   const DBusError *error,
2163                                   DBusMessage     *in_reply_to)
2164 {
2165   DBusMessage *reply;
2166
2167   _dbus_assert (error != NULL);
2168   _DBUS_ASSERT_ERROR_IS_SET (error);
2169
2170   _dbus_verbose ("Sending error reply %s \"%s\"\n",
2171                  error->name, error->message);
2172
2173   reply = dbus_message_new_error (in_reply_to,
2174                                   error->name,
2175                                   error->message);
2176   if (reply == NULL)
2177     return FALSE;
2178
2179   if (!bus_transaction_send_from_driver (transaction, connection, reply))
2180     {
2181       dbus_message_unref (reply);
2182       return FALSE;
2183     }
2184
2185   dbus_message_unref (reply);
2186
2187   return TRUE;
2188 }
2189
2190 dbus_bool_t
2191 bus_transaction_add_cancel_hook (BusTransaction               *transaction,
2192                                  BusTransactionCancelFunction  cancel_function,
2193                                  void                         *data,
2194                                  DBusFreeFunction              free_data_function)
2195 {
2196   CancelHook *ch;
2197
2198   ch = dbus_new (CancelHook, 1);
2199   if (ch == NULL)
2200     return FALSE;
2201
2202   _dbus_verbose ("     adding cancel hook function = %p data = %p\n",
2203                  cancel_function, data);
2204
2205   ch->cancel_function = cancel_function;
2206   ch->data = data;
2207   ch->free_data_function = free_data_function;
2208
2209   /* It's important that the hooks get run in reverse order that they
2210    * were added
2211    */
2212   if (!_dbus_list_prepend (&transaction->cancel_hooks, ch))
2213     {
2214       dbus_free (ch);
2215       return FALSE;
2216     }
2217
2218   return TRUE;
2219 }