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 1.2
   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 <dbus/dbus-list.h>
  31 #include <dbus/dbus-hash.h>
  32 #include <dbus/dbus-timeout.h>
  33
  34 static void bus_connection_remove_transactions (DBusConnection *connection);
  35
  36 typedef struct
  37 {
  38   BusExpireItem expire_item;
  39
  40   DBusConnection *will_get_reply;
  41   DBusConnection *will_send_reply;
  42
  43   dbus_uint32_t reply_serial;
  44
  45 } BusPendingReply;
  46
  47 struct BusConnections
  48 {
  49   int refcount;
  50   DBusList *completed;  /**< List of all completed connections */
  51   int n_completed;      /**< Length of completed list */
  52   DBusList *incomplete; /**< List of all not-yet-active connections */
  53   int n_incomplete;     /**< Length of incomplete list */
  54   BusContext *context;
  55   DBusHashTable *completed_by_user; /**< Number of completed connections for each UID */
  56   DBusTimeout *expire_timeout; /**< Timeout for expiring incomplete connections. */
  57   int stamp;            /**< Incrementing number */
  58   BusExpireList *pending_replies; /**< List of pending replies */
  59 };
  60
  61 static dbus_int32_t connection_data_slot = -1;
  62
  63 typedef struct
  64 {
  65   BusConnections *connections;
  66   DBusList *link_in_connection_list;
  67   DBusConnection *connection;
  68   DBusList *services_owned;
  69   int n_services_owned;
  70   DBusList *match_rules;
  71   int n_match_rules;
  72   char *name;
  73   DBusList *transaction_messages; /**< Stuff we need to send as part of a transaction */
  74   DBusMessage *oom_message;
  75   DBusPreallocatedSend *oom_preallocated;
  76   BusClientPolicy *policy;
  77
  78   long connection_tv_sec;  /**< Time when we connected (seconds component) */
  79   long connection_tv_usec; /**< Time when we connected (microsec component) */
  80   int stamp;               /**< connections->stamp last time we were traversed */
  81 } BusConnectionData;
  82
  83 static void bus_pending_reply_expired (BusExpireList *list,
  84                                        DBusList      *link,
  85                                        void          *data);
  86
  87 static void bus_connection_drop_pending_replies (BusConnections  *connections,
  88                                                  DBusConnection  *connection);
  89
  90 static dbus_bool_t expire_incomplete_timeout (void *data);
  91
  92 #define BUS_CONNECTION_DATA(connection) (dbus_connection_get_data ((connection), connection_data_slot))
  93
  94 static DBusLoop*
  95 connection_get_loop (DBusConnection *connection)
  96 {
  97   BusConnectionData *d;
  98
  99   d = BUS_CONNECTION_DATA (connection);
 100
 101   return bus_context_get_loop (d->connections->context);
 102 }
 103
 104
 105 static int
 106 get_connections_for_uid (BusConnections *connections,
 107                          dbus_uid_t      uid)
 108 {
 109   void *val;
 110   int current_count;
 111
 112   /* val is NULL is 0 when it isn't in the hash yet */
 113
 114   val = _dbus_hash_table_lookup_ulong (connections->completed_by_user,
 115                                        uid);
 116
 117   current_count = _DBUS_POINTER_TO_INT (val);
 118
 119   return current_count;
 120 }
 121
 122 static dbus_bool_t
 123 adjust_connections_for_uid (BusConnections *connections,
 124                             dbus_uid_t      uid,
 125                             int             adjustment)
 126 {
 127   int current_count;
 128
 129   current_count = get_connections_for_uid (connections, uid);
 130
 131   _dbus_verbose ("Adjusting connection count for UID " DBUS_UID_FORMAT
 132                  ": was %d adjustment %d making %d\n",
 133                  uid, current_count, adjustment, current_count + adjustment);
 134
 135   _dbus_assert (current_count >= 0);
 136
 137   current_count += adjustment;
 138
 139   _dbus_assert (current_count >= 0);
 140
 141   if (current_count == 0)
 142     {
 143       _dbus_hash_table_remove_ulong (connections->completed_by_user, uid);
 144       return TRUE;
 145     }
 146   else
 147     {
 148       dbus_bool_t retval;
 149
 150       retval = _dbus_hash_table_insert_ulong (connections->completed_by_user,
 151                                               uid, _DBUS_INT_TO_POINTER (current_count));
 152
 153       /* only positive adjustment can fail as otherwise
 154        * a hash entry should already exist
 155        */
 156       _dbus_assert (adjustment > 0 ||
 157                     (adjustment <= 0 && retval));
 158
 159       return retval;
 160     }
 161 }
 162
 163 void
 164 bus_connection_disconnected (DBusConnection *connection)
 165 {
 166   BusConnectionData *d;
 167   BusService *service;
 168   BusMatchmaker *matchmaker;
 169
 170   d = BUS_CONNECTION_DATA (connection);
 171   _dbus_assert (d != NULL);
 172
 173   _dbus_verbose ("%s disconnected, dropping all service ownership and releasing\n",
 174                  d->name ? d->name : "(inactive)");
 175
 176   /* Delete our match rules */
 177   if (d->n_match_rules > 0)
 178     {
 179       matchmaker = bus_context_get_matchmaker (d->connections->context);
 180       bus_matchmaker_disconnected (matchmaker, connection);
 181     }
 182
 183   /* Drop any service ownership. FIXME Unfortunately, this requires
 184    * memory allocation and there doesn't seem to be a good way to
 185    * handle it other than sleeping; we can't "fail" the operation of
 186    * disconnecting a client, and preallocating a broadcast "service is
 187    * now gone" message for every client-service pair seems kind of
 188    * involved. Probably we need to do that though.
 189    */
 190   while ((service = _dbus_list_get_last (&d->services_owned)))
 191     {
 192       BusTransaction *transaction;
 193       DBusError error;
 194
 195     retry:
 196
 197       dbus_error_init (&error);
 198
 199       transaction = NULL;
 200       while (transaction == NULL)
 201         {
 202           transaction = bus_transaction_new (d->connections->context);
 203           _dbus_wait_for_memory ();
 204         }
 205
 206       if (!bus_service_remove_owner (service, connection,
 207                                      transaction, &error))
 208         {
 209           _DBUS_ASSERT_ERROR_IS_SET (&error);
 210
 211           if (dbus_error_has_name (&error, DBUS_ERROR_NO_MEMORY))
 212             {
 213               dbus_error_free (&error);
 214               bus_transaction_cancel_and_free (transaction);
 215               _dbus_wait_for_memory ();
 216               goto retry;
 217             }
 218           else
 219             {
 220               _dbus_verbose ("Failed to remove service owner: %s %s\n",
 221                              error.name, error.message);
 222               _dbus_assert_not_reached ("Removing service owner failed for non-memory-related reason");
 223             }
 224         }
 225
 226       bus_transaction_execute_and_free (transaction);
 227     }
 228
 229   bus_dispatch_remove_connection (connection);
 230
 231   /* no more watching */
 232   if (!dbus_connection_set_watch_functions (connection,
 233                                             NULL, NULL, NULL,
 234                                             connection,
 235                                             NULL))
 236     _dbus_assert_not_reached ("setting watch functions to NULL failed");
 237
 238   if (!dbus_connection_set_timeout_functions (connection,
 239                                               NULL, NULL, NULL,
 240                                               connection,
 241                                               NULL))
 242     _dbus_assert_not_reached ("setting timeout functions to NULL failed");
 243
 244   dbus_connection_set_unix_user_function (connection,
 245                                           NULL, NULL, NULL);
 246
 247   dbus_connection_set_dispatch_status_function (connection,
 248                                                 NULL, NULL, NULL);
 249
 250   bus_connection_remove_transactions (connection);
 251
 252   if (d->link_in_connection_list != NULL)
 253     {
 254       if (d->name != NULL)
 255         {
 256           unsigned long uid;
 257
 258           _dbus_list_remove_link (&d->connections->completed, d->link_in_connection_list);
 259           d->link_in_connection_list = NULL;
 260           d->connections->n_completed -= 1;
 261
 262           if (dbus_connection_get_unix_user (connection, &uid))
 263             {
 264               if (!adjust_connections_for_uid (d->connections,
 265                                                uid, -1))
 266                 _dbus_assert_not_reached ("adjusting downward should never fail");
 267             }
 268         }
 269       else
 270         {
 271           _dbus_list_remove_link (&d->connections->incomplete, d->link_in_connection_list);
 272           d->link_in_connection_list = NULL;
 273           d->connections->n_incomplete -= 1;
 274         }
 275
 276       _dbus_assert (d->connections->n_incomplete >= 0);
 277       _dbus_assert (d->connections->n_completed >= 0);
 278     }
 279
 280   bus_connection_drop_pending_replies (d->connections, connection);
 281
 282   /* frees "d" as side effect */
 283   dbus_connection_set_data (connection,
 284                             connection_data_slot,
 285                             NULL, NULL);
 286
 287   dbus_connection_unref (connection);
 288 }
 289
 290 static dbus_bool_t
 291 connection_watch_callback (DBusWatch     *watch,
 292                            unsigned int   condition,
 293                            void          *data)
 294 {
 295  /* FIXME this can be done in dbus-mainloop.c
 296   * if the code in activation.c for the babysitter
 297   * watch handler is fixed.
 298   */
 299
 300 #if 0
 301   _dbus_verbose ("Calling handle_watch\n");
 302 #endif
 303   return dbus_watch_handle (watch, condition);
 304 }
 305
 306 static dbus_bool_t
 307 add_connection_watch (DBusWatch      *watch,
 308                       void           *data)
 309 {
 310   DBusConnection *connection = data;
 311
 312   return _dbus_loop_add_watch (connection_get_loop (connection),
 313                                watch, connection_watch_callback, connection,
 314                                NULL);
 315 }
 316
 317 static void
 318 remove_connection_watch (DBusWatch      *watch,
 319                          void           *data)
 320 {
 321   DBusConnection *connection = data;
 322
 323   _dbus_loop_remove_watch (connection_get_loop (connection),
 324                            watch, connection_watch_callback, connection);
 325 }
 326
 327 static void
 328 connection_timeout_callback (DBusTimeout   *timeout,
 329                              void          *data)
 330 {
 331   /* DBusConnection *connection = data; */
 332
 333   /* can return FALSE on OOM but we just let it fire again later */
 334   dbus_timeout_handle (timeout);
 335 }
 336
 337 static dbus_bool_t
 338 add_connection_timeout (DBusTimeout    *timeout,
 339                         void           *data)
 340 {
 341   DBusConnection *connection = data;
 342
 343   return _dbus_loop_add_timeout (connection_get_loop (connection),
 344                                  timeout, connection_timeout_callback, connection, NULL);
 345 }
 346
 347 static void
 348 remove_connection_timeout (DBusTimeout    *timeout,
 349                            void           *data)
 350 {
 351   DBusConnection *connection = data;
 352
 353   _dbus_loop_remove_timeout (connection_get_loop (connection),
 354                              timeout, connection_timeout_callback, connection);
 355 }
 356
 357 static void
 358 dispatch_status_function (DBusConnection    *connection,
 359                           DBusDispatchStatus new_status,
 360                           void              *data)
 361 {
 362   DBusLoop *loop = data;
 363
 364   if (new_status != DBUS_DISPATCH_COMPLETE)
 365     {
 366       while (!_dbus_loop_queue_dispatch (loop, connection))
 367         _dbus_wait_for_memory ();
 368     }
 369 }
 370
 371 static dbus_bool_t
 372 allow_user_function (DBusConnection *connection,
 373                      unsigned long   uid,
 374                      void           *data)
 375 {
 376   BusConnectionData *d;
 377
 378   d = BUS_CONNECTION_DATA (connection);
 379
 380   _dbus_assert (d != NULL);
 381
 382   return bus_context_allow_user (d->connections->context, uid);
 383 }
 384
 385 static void
 386 free_connection_data (void *data)
 387 {
 388   BusConnectionData *d = data;
 389
 390   /* services_owned should be NULL since we should be disconnected */
 391   _dbus_assert (d->services_owned == NULL);
 392   _dbus_assert (d->n_services_owned == 0);
 393   /* similarly */
 394   _dbus_assert (d->transaction_messages == NULL);
 395
 396   if (d->oom_preallocated)
 397     dbus_connection_free_preallocated_send (d->connection, d->oom_preallocated);
 398
 399   if (d->oom_message)
 400     dbus_message_unref (d->oom_message);
 401
 402   if (d->policy)
 403     bus_client_policy_unref (d->policy);
 404
 405   dbus_free (d->name);
 406
 407   dbus_free (d);
 408 }
 409
 410 static void
 411 call_timeout_callback (DBusTimeout   *timeout,
 412                        void          *data)
 413 {
 414   /* can return FALSE on OOM but we just let it fire again later */
 415   dbus_timeout_handle (timeout);
 416 }
 417
 418 BusConnections*
 419 bus_connections_new (BusContext *context)
 420 {
 421   BusConnections *connections;
 422
 423   if (!dbus_connection_allocate_data_slot (&connection_data_slot))
 424     goto failed_0;
 425
 426   connections = dbus_new0 (BusConnections, 1);
 427   if (connections == NULL)
 428     goto failed_1;
 429
 430   connections->completed_by_user = _dbus_hash_table_new (DBUS_HASH_ULONG,
 431                                                          NULL, NULL);
 432   if (connections->completed_by_user == NULL)
 433     goto failed_2;
 434
 435   connections->expire_timeout = _dbus_timeout_new (100, /* irrelevant */
 436                                                    expire_incomplete_timeout,
 437                                                    connections, NULL);
 438   if (connections->expire_timeout == NULL)
 439     goto failed_3;
 440
 441   _dbus_timeout_set_enabled (connections->expire_timeout, FALSE);
 442
 443   connections->pending_replies = bus_expire_list_new (bus_context_get_loop (context),
 444                                                       bus_context_get_reply_timeout (context),
 445                                                       bus_pending_reply_expired,
 446                                                       connections);
 447   if (connections->pending_replies == NULL)
 448     goto failed_4;
 449
 450   if (!_dbus_loop_add_timeout (bus_context_get_loop (context),
 451                                connections->expire_timeout,
 452                                call_timeout_callback, NULL, NULL))
 453     goto failed_5;
 454
 455   connections->refcount = 1;
 456   connections->context = context;
 457
 458   return connections;
 459
 460  failed_5:
 461   bus_expire_list_free (connections->pending_replies);
 462  failed_4:
 463   _dbus_timeout_unref (connections->expire_timeout);
 464  failed_3:
 465   _dbus_hash_table_unref (connections->completed_by_user);
 466  failed_2:
 467   dbus_free (connections);
 468  failed_1:
 469   dbus_connection_free_data_slot (&connection_data_slot);
 470  failed_0:
 471   return NULL;
 472 }
 473
 474 void
 475 bus_connections_ref (BusConnections *connections)
 476 {
 477   _dbus_assert (connections->refcount > 0);
 478   connections->refcount += 1;
 479 }
 480
 481 void
 482 bus_connections_unref (BusConnections *connections)
 483 {
 484   _dbus_assert (connections->refcount > 0);
 485   connections->refcount -= 1;
 486   if (connections->refcount == 0)
 487     {
 488       /* drop all incomplete */
 489       while (connections->incomplete != NULL)
 490         {
 491           DBusConnection *connection;
 492
 493           connection = connections->incomplete->data;
 494
 495           dbus_connection_ref (connection);
 496           dbus_connection_disconnect (connection);
 497           bus_connection_disconnected (connection);
 498           dbus_connection_unref (connection);
 499         }
 500
 501       _dbus_assert (connections->n_incomplete == 0);
 502
 503       /* drop all real connections */
 504       while (connections->completed != NULL)
 505         {
 506           DBusConnection *connection;
 507
 508           connection = connections->completed->data;
 509
 510           dbus_connection_ref (connection);
 511           dbus_connection_disconnect (connection);
 512           bus_connection_disconnected (connection);
 513           dbus_connection_unref (connection);
 514         }
 515
 516       _dbus_assert (connections->n_completed == 0);
 517
 518       _dbus_assert (connections->pending_replies->n_items == 0);
 519       bus_expire_list_free (connections->pending_replies);
 520
 521       _dbus_loop_remove_timeout (bus_context_get_loop (connections->context),
 522                                  connections->expire_timeout,
 523                                  call_timeout_callback, NULL);
 524
 525       _dbus_timeout_unref (connections->expire_timeout);
 526
 527       _dbus_hash_table_unref (connections->completed_by_user);
 528
 529       dbus_free (connections);
 530
 531       dbus_connection_free_data_slot (&connection_data_slot);
 532     }
 533 }
 534
 535 dbus_bool_t
 536 bus_connections_setup_connection (BusConnections *connections,
 537                                   DBusConnection *connection)
 538 {
 539   BusConnectionData *d;
 540   dbus_bool_t retval;
 541
 542   d = dbus_new0 (BusConnectionData, 1);
 543
 544   if (d == NULL)
 545     return FALSE;
 546
 547   d->connections = connections;
 548   d->connection = connection;
 549
 550   _dbus_get_current_time (&d->connection_tv_sec,
 551                           &d->connection_tv_usec);
 552
 553   _dbus_assert (connection_data_slot >= 0);
 554
 555   if (!dbus_connection_set_data (connection,
 556                                  connection_data_slot,
 557                                  d, free_connection_data))
 558     {
 559       dbus_free (d);
 560       return FALSE;
 561     }
 562
 563   retval = FALSE;
 564
 565   if (!dbus_connection_set_watch_functions (connection,
 566                                             add_connection_watch,
 567                                             remove_connection_watch,
 568                                             NULL,
 569                                             connection,
 570                                             NULL))
 571     goto out;
 572
 573   if (!dbus_connection_set_timeout_functions (connection,
 574                                               add_connection_timeout,
 575                                               remove_connection_timeout,
 576                                               NULL,
 577                                               connection, NULL))
 578     goto out;
 579
 580   dbus_connection_set_unix_user_function (connection,
 581                                           allow_user_function,
 582                                           NULL, NULL);
 583
 584   dbus_connection_set_dispatch_status_function (connection,
 585                                                 dispatch_status_function,
 586                                                 bus_context_get_loop (connections->context),
 587                                                 NULL);
 588
 589   d->link_in_connection_list = _dbus_list_alloc_link (connection);
 590   if (d->link_in_connection_list == NULL)
 591     goto out;
 592
 593   /* Setup the connection with the dispatcher */
 594   if (!bus_dispatch_add_connection (connection))
 595     goto out;
 596
 597   if (dbus_connection_get_dispatch_status (connection) != DBUS_DISPATCH_COMPLETE)
 598     {
 599       if (!_dbus_loop_queue_dispatch (bus_context_get_loop (connections->context), connection))
 600         {
 601           bus_dispatch_remove_connection (connection);
 602           goto out;
 603         }
 604     }
 605
 606   _dbus_list_append_link (&connections->incomplete, d->link_in_connection_list);
 607   connections->n_incomplete += 1;
 608
 609   dbus_connection_ref (connection);
 610
 611   /* Note that we might disconnect ourselves here, but it only takes
 612    * effect on return to the main loop. We call this to free up
 613    * expired connections if possible, and to queue the timeout for our
 614    * own expiration.
 615    */
 616   bus_connections_expire_incomplete (connections);
 617
 618   /* And we might also disconnect ourselves here, but again it
 619    * only takes effect on return to main loop.
 620    */
 621   if (connections->n_incomplete >
 622       bus_context_get_max_incomplete_connections (connections->context))
 623     {
 624       _dbus_verbose ("Number of incomplete connections exceeds max, dropping oldest one\n");
 625
 626       _dbus_assert (connections->incomplete != NULL);
 627       /* Disconnect the oldest unauthenticated connection.  FIXME
 628        * would it be more secure to drop a *random* connection?  This
 629        * algorithm seems to mean that if someone can create new
 630        * connections quickly enough, they can keep anyone else from
 631        * completing authentication. But random may or may not really
 632        * help with that, a more elaborate solution might be required.
 633        */
 634       dbus_connection_disconnect (connections->incomplete->data);
 635     }
 636
 637   retval = TRUE;
 638
 639  out:
 640   if (!retval)
 641     {
 642       if (!dbus_connection_set_watch_functions (connection,
 643                                                 NULL, NULL, NULL,
 644                                                 connection,
 645                                                 NULL))
 646         _dbus_assert_not_reached ("setting watch functions to NULL failed");
 647
 648       if (!dbus_connection_set_timeout_functions (connection,
 649                                                   NULL, NULL, NULL,
 650                                                   connection,
 651                                                   NULL))
 652         _dbus_assert_not_reached ("setting timeout functions to NULL failed");
 653
 654       dbus_connection_set_unix_user_function (connection,
 655                                               NULL, NULL, NULL);
 656
 657       dbus_connection_set_dispatch_status_function (connection,
 658                                                     NULL, NULL, NULL);
 659
 660       if (d->link_in_connection_list != NULL)
 661         {
 662           _dbus_assert (d->link_in_connection_list->next == NULL);
 663           _dbus_assert (d->link_in_connection_list->prev == NULL);
 664           _dbus_list_free_link (d->link_in_connection_list);
 665           d->link_in_connection_list = NULL;
 666         }
 667
 668       if (!dbus_connection_set_data (connection,
 669                                      connection_data_slot,
 670                                      NULL, NULL))
 671         _dbus_assert_not_reached ("failed to set connection data to null");
 672
 673       /* "d" has now been freed */
 674     }
 675
 676   return retval;
 677 }
 678
 679 void
 680 bus_connections_expire_incomplete (BusConnections *connections)
 681 {
 682   int next_interval;
 683
 684   next_interval = -1;
 685
 686   if (connections->incomplete != NULL)
 687     {
 688       long tv_sec, tv_usec;
 689       DBusList *link;
 690       int auth_timeout;
 691
 692       _dbus_get_current_time (&tv_sec, &tv_usec);
 693       auth_timeout = bus_context_get_auth_timeout (connections->context);
 694
 695       link = _dbus_list_get_first_link (&connections->incomplete);
 696       while (link != NULL)
 697         {
 698           DBusList *next = _dbus_list_get_next_link (&connections->incomplete, link);
 699           DBusConnection *connection;
 700           BusConnectionData *d;
 701           double elapsed;
 702
 703           connection = link->data;
 704
 705           d = BUS_CONNECTION_DATA (connection);
 706
 707           _dbus_assert (d != NULL);
 708
 709           elapsed = ELAPSED_MILLISECONDS_SINCE (d->connection_tv_sec,
 710                                                 d->connection_tv_usec,
 711                                                 tv_sec, tv_usec);
 712
 713           if (elapsed >= (double) auth_timeout)
 714             {
 715               _dbus_verbose ("Timing out authentication for connection %p\n", connection);
 716               dbus_connection_disconnect (connection);
 717             }
 718           else
 719             {
 720               /* We can end the loop, since the connections are in oldest-first order */
 721               next_interval = ((double)auth_timeout) - elapsed;
 722               _dbus_verbose ("Connection %p authentication expires in %d milliseconds\n",
 723                              connection, next_interval);
 724
 725               break;
 726             }
 727
 728           link = next;
 729         }
 730     }
 731
 732   bus_expire_timeout_set_interval (connections->expire_timeout,
 733                                    next_interval);
 734 }
 735
 736 static dbus_bool_t
 737 expire_incomplete_timeout (void *data)
 738 {
 739   BusConnections *connections = data;
 740
 741   _dbus_verbose ("Running %s\n", _DBUS_FUNCTION_NAME);
 742
 743   /* note that this may remove the timeout */
 744   bus_connections_expire_incomplete (connections);
 745
 746   return TRUE;
 747 }
 748
 749 dbus_bool_t
 750 bus_connection_get_groups  (DBusConnection   *connection,
 751                             unsigned long   **groups,
 752                             int              *n_groups,
 753                             DBusError        *error)
 754 {
 755   BusConnectionData *d;
 756   unsigned long uid;
 757   DBusUserDatabase *user_database;
 758
 759   d = BUS_CONNECTION_DATA (connection);
 760
 761   _dbus_assert (d != NULL);
 762
 763   user_database = bus_context_get_user_database (d->connections->context);
 764
 765   *groups = NULL;
 766   *n_groups = 0;
 767
 768   if (dbus_connection_get_unix_user (connection, &uid))
 769     {
 770       if (!_dbus_user_database_get_groups (user_database,
 771                                            uid, groups, n_groups,
 772                                            error))
 773         {
 774           _DBUS_ASSERT_ERROR_IS_SET (error);
 775           _dbus_verbose ("Did not get any groups for UID %lu\n",
 776                          uid);
 777           return FALSE;
 778         }
 779       else
 780         {
 781           _dbus_verbose ("Got %d groups for UID %lu\n",
 782                          *n_groups, uid);
 783           return TRUE;
 784         }
 785     }
 786   else
 787     return TRUE; /* successfully got 0 groups */
 788 }
 789
 790 dbus_bool_t
 791 bus_connection_is_in_group (DBusConnection *connection,
 792                             unsigned long   gid)
 793 {
 794   int i;
 795   unsigned long *group_ids;
 796   int n_group_ids;
 797
 798   if (!bus_connection_get_groups (connection, &group_ids, &n_group_ids,
 799                                   NULL))
 800     return FALSE;
 801
 802   i = 0;
 803   while (i < n_group_ids)
 804     {
 805       if (group_ids[i] == gid)
 806         {
 807           dbus_free (group_ids);
 808           return TRUE;
 809         }
 810       ++i;
 811     }
 812
 813   dbus_free (group_ids);
 814   return FALSE;
 815 }
 816
 817 BusClientPolicy*
 818 bus_connection_get_policy (DBusConnection *connection)
 819 {
 820   BusConnectionData *d;
 821
 822   d = BUS_CONNECTION_DATA (connection);
 823
 824   _dbus_assert (d != NULL);
 825   _dbus_assert (d->policy != NULL);
 826
 827   return d->policy;
 828 }
 829
 830 static dbus_bool_t
 831 foreach_active (BusConnections               *connections,
 832                 BusConnectionForeachFunction  function,
 833                 void                         *data)
 834 {
 835   DBusList *link;
 836
 837   link = _dbus_list_get_first_link (&connections->completed);
 838   while (link != NULL)
 839     {
 840       DBusConnection *connection = link->data;
 841       DBusList *next = _dbus_list_get_next_link (&connections->completed, link);
 842
 843       if (!(* function) (connection, data))
 844         return FALSE;
 845
 846       link = next;
 847     }
 848
 849   return TRUE;
 850 }
 851
 852 static dbus_bool_t
 853 foreach_inactive (BusConnections               *connections,
 854                   BusConnectionForeachFunction  function,
 855                   void                         *data)
 856 {
 857   DBusList *link;
 858
 859   link = _dbus_list_get_first_link (&connections->incomplete);
 860   while (link != NULL)
 861     {
 862       DBusConnection *connection = link->data;
 863       DBusList *next = _dbus_list_get_next_link (&connections->incomplete, link);
 864
 865       if (!(* function) (connection, data))
 866         return FALSE;
 867
 868       link = next;
 869     }
 870
 871   return TRUE;
 872 }
 873
 874 /**
 875  * Calls function on each active connection; if the function returns
 876  * #FALSE, stops iterating. Active connections are authenticated
 877  * and have sent a Hello message.
 878  *
 879  * @param connections the connections object
 880  * @param function the function
 881  * @param data data to pass to it as a second arg
 882  */
 883 void
 884 bus_connections_foreach_active (BusConnections               *connections,
 885                                 BusConnectionForeachFunction  function,
 886                                 void                         *data)
 887 {
 888   foreach_active (connections, function, data);
 889 }
 890
 891 /**
 892  * Calls function on each connection; if the function returns
 893  * #FALSE, stops iterating.
 894  *
 895  * @param connections the connections object
 896  * @param function the function
 897  * @param data data to pass to it as a second arg
 898  */
 899 void
 900 bus_connections_foreach (BusConnections               *connections,
 901                          BusConnectionForeachFunction  function,
 902                          void                         *data)
 903 {
 904   if (!foreach_active (connections, function, data))
 905     return;
 906
 907   foreach_inactive (connections, function, data);
 908 }
 909
 910 BusContext*
 911 bus_connections_get_context (BusConnections *connections)
 912 {
 913   return connections->context;
 914 }
 915
 916 /*
 917  * This is used to avoid covering the same connection twice when
 918  * traversing connections. Note that it assumes we will
 919  * bus_connection_mark_stamp() each connection at least once per
 920  * INT_MAX increments of the global stamp, or wraparound would break
 921  * things.
 922  */
 923 void
 924 bus_connections_increment_stamp (BusConnections *connections)
 925 {
 926   connections->stamp += 1;
 927 }
 928
 929 /* Mark connection with current stamp, return TRUE if it
 930  * didn't already have that stamp
 931  */
 932 dbus_bool_t
 933 bus_connection_mark_stamp (DBusConnection *connection)
 934 {
 935   BusConnectionData *d;
 936
 937   d = BUS_CONNECTION_DATA (connection);
 938
 939   _dbus_assert (d != NULL);
 940
 941   if (d->stamp == d->connections->stamp)
 942     return FALSE;
 943   else
 944     {
 945       d->stamp = d->connections->stamp;
 946       return TRUE;
 947     }
 948 }
 949
 950 BusContext*
 951 bus_connection_get_context (DBusConnection *connection)
 952 {
 953   BusConnectionData *d;
 954
 955   d = BUS_CONNECTION_DATA (connection);
 956
 957   _dbus_assert (d != NULL);
 958
 959   return d->connections->context;
 960 }
 961
 962 BusConnections*
 963 bus_connection_get_connections (DBusConnection *connection)
 964 {
 965   BusConnectionData *d;
 966
 967   d = BUS_CONNECTION_DATA (connection);
 968
 969   _dbus_assert (d != NULL);
 970
 971   return d->connections;
 972 }
 973
 974 BusRegistry*
 975 bus_connection_get_registry (DBusConnection *connection)
 976 {
 977   BusConnectionData *d;
 978
 979   d = BUS_CONNECTION_DATA (connection);
 980
 981   _dbus_assert (d != NULL);
 982
 983   return bus_context_get_registry (d->connections->context);
 984 }
 985
 986 BusActivation*
 987 bus_connection_get_activation (DBusConnection *connection)
 988 {
 989   BusConnectionData *d;
 990
 991   d = BUS_CONNECTION_DATA (connection);
 992
 993   _dbus_assert (d != NULL);
 994
 995   return bus_context_get_activation (d->connections->context);
 996 }
 997
 998 BusMatchmaker*
 999 bus_connection_get_matchmaker (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_matchmaker (d->connections->context);
1008 }
1009
1010 /**
1011  * Checks whether the connection is registered with the message bus.
1012  *
1013  * @param connection the connection
1014  * @returns #TRUE if we're an active message bus participant
1015  */
1016 dbus_bool_t
1017 bus_connection_is_active (DBusConnection *connection)
1018 {
1019   BusConnectionData *d;
1020
1021   d = BUS_CONNECTION_DATA (connection);
1022
1023   return d != NULL && d->name != NULL;
1024 }
1025
1026 dbus_bool_t
1027 bus_connection_preallocate_oom_error (DBusConnection *connection)
1028 {
1029   DBusMessage *message;
1030   DBusPreallocatedSend *preallocated;
1031   BusConnectionData *d;
1032
1033   d = BUS_CONNECTION_DATA (connection);
1034
1035   _dbus_assert (d != NULL);
1036
1037   if (d->oom_preallocated != NULL)
1038     return TRUE;
1039
1040   preallocated = dbus_connection_preallocate_send (connection);
1041   if (preallocated == NULL)
1042     return FALSE;
1043
1044   message = dbus_message_new (DBUS_MESSAGE_TYPE_ERROR);
1045
1046   if (message == NULL)
1047     {
1048       dbus_connection_free_preallocated_send (connection, preallocated);
1049       return FALSE;
1050     }
1051
1052   /* d->name may be NULL, but that is OK */
1053   if (!dbus_message_set_error_name (message, DBUS_ERROR_NO_MEMORY) ||
1054       !dbus_message_set_destination (message, d->name) ||
1055       !dbus_message_set_sender (message,
1056                                 DBUS_SERVICE_ORG_FREEDESKTOP_DBUS))
1057     {
1058       dbus_connection_free_preallocated_send (connection, preallocated);
1059       dbus_message_unref (message);
1060       return FALSE;
1061     }
1062
1063   /* set reply serial to placeholder value just so space is already allocated
1064    * for it.
1065    */
1066   if (!dbus_message_set_reply_serial (message, 14))
1067     {
1068       dbus_connection_free_preallocated_send (connection, preallocated);
1069       dbus_message_unref (message);
1070       return FALSE;
1071     }
1072
1073   d->oom_message = message;
1074   d->oom_preallocated = preallocated;
1075
1076   return TRUE;
1077 }
1078
1079 void
1080 bus_connection_send_oom_error (DBusConnection *connection,
1081                                DBusMessage    *in_reply_to)
1082 {
1083   BusConnectionData *d;
1084
1085   d = BUS_CONNECTION_DATA (connection);
1086
1087   _dbus_assert (d != NULL);
1088   _dbus_assert (d->oom_message != NULL);
1089
1090   /* should always succeed since we set it to a placeholder earlier */
1091   if (!dbus_message_set_reply_serial (d->oom_message,
1092                                       dbus_message_get_serial (in_reply_to)))
1093     _dbus_assert_not_reached ("Failed to set reply serial for preallocated oom message");
1094
1095   _dbus_assert (dbus_message_get_sender (d->oom_message) != NULL);
1096
1097   dbus_connection_send_preallocated (connection, d->oom_preallocated,
1098                                      d->oom_message, NULL);
1099
1100   dbus_message_unref (d->oom_message);
1101   d->oom_message = NULL;
1102   d->oom_preallocated = NULL;
1103 }
1104
1105 void
1106 bus_connection_add_match_rule_link (DBusConnection *connection,
1107                                     DBusList       *link)
1108 {
1109   BusConnectionData *d;
1110
1111   d = BUS_CONNECTION_DATA (connection);
1112   _dbus_assert (d != NULL);
1113
1114   _dbus_list_append_link (&d->match_rules, link);
1115
1116   d->n_match_rules += 1;
1117 }
1118
1119 dbus_bool_t
1120 bus_connection_add_match_rule (DBusConnection *connection,
1121                                BusMatchRule   *rule)
1122 {
1123     DBusList *link;
1124
1125   link = _dbus_list_alloc_link (rule);
1126
1127   if (link == NULL)
1128     return FALSE;
1129
1130   bus_connection_add_match_rule_link (connection, link);
1131
1132   return TRUE;
1133 }
1134
1135 void
1136 bus_connection_remove_match_rule (DBusConnection *connection,
1137                                   BusMatchRule   *rule)
1138 {
1139   BusConnectionData *d;
1140
1141   d = BUS_CONNECTION_DATA (connection);
1142   _dbus_assert (d != NULL);
1143
1144   _dbus_list_remove_last (&d->match_rules, rule);
1145
1146   d->n_match_rules -= 1;
1147   _dbus_assert (d->n_match_rules >= 0);
1148 }
1149
1150 int
1151 bus_connection_get_n_match_rules (DBusConnection *connection)
1152 {
1153   BusConnectionData *d;
1154
1155   d = BUS_CONNECTION_DATA (connection);
1156   _dbus_assert (d != NULL);
1157
1158   return d->n_match_rules;
1159 }
1160
1161 void
1162 bus_connection_add_owned_service_link (DBusConnection *connection,
1163                                        DBusList       *link)
1164 {
1165   BusConnectionData *d;
1166
1167   d = BUS_CONNECTION_DATA (connection);
1168   _dbus_assert (d != NULL);
1169
1170   _dbus_list_append_link (&d->services_owned, link);
1171
1172   d->n_services_owned += 1;
1173 }
1174
1175 dbus_bool_t
1176 bus_connection_add_owned_service (DBusConnection *connection,
1177                                   BusService     *service)
1178 {
1179   DBusList *link;
1180
1181   link = _dbus_list_alloc_link (service);
1182
1183   if (link == NULL)
1184     return FALSE;
1185
1186   bus_connection_add_owned_service_link (connection, link);
1187
1188   return TRUE;
1189 }
1190
1191 void
1192 bus_connection_remove_owned_service (DBusConnection *connection,
1193                                      BusService     *service)
1194 {
1195   BusConnectionData *d;
1196
1197   d = BUS_CONNECTION_DATA (connection);
1198   _dbus_assert (d != NULL);
1199
1200   _dbus_list_remove_last (&d->services_owned, service);
1201
1202   d->n_services_owned -= 1;
1203   _dbus_assert (d->n_services_owned >= 0);
1204 }
1205
1206 int
1207 bus_connection_get_n_services_owned (DBusConnection *connection)
1208 {
1209   BusConnectionData *d;
1210
1211   d = BUS_CONNECTION_DATA (connection);
1212   _dbus_assert (d != NULL);
1213
1214   return d->n_services_owned;
1215 }
1216
1217 dbus_bool_t
1218 bus_connection_complete (DBusConnection   *connection,
1219                          const DBusString *name,
1220                          DBusError        *error)
1221 {
1222   BusConnectionData *d;
1223   unsigned long uid;
1224
1225   d = BUS_CONNECTION_DATA (connection);
1226   _dbus_assert (d != NULL);
1227   _dbus_assert (d->name == NULL);
1228   _dbus_assert (d->policy == NULL);
1229
1230   _dbus_assert (!bus_connection_is_active (connection));
1231
1232   if (!_dbus_string_copy_data (name, &d->name))
1233     {
1234       BUS_SET_OOM (error);
1235       return FALSE;
1236     }
1237
1238   _dbus_assert (d->name != NULL);
1239
1240   _dbus_verbose ("Name %s assigned to %p\n", d->name, connection);
1241
1242   d->policy = bus_context_create_client_policy (d->connections->context,
1243                                                 connection,
1244                                                 error);
1245
1246   /* we may have a NULL policy on OOM or error getting list of
1247    * groups for a user. In the latter case we don't handle it so
1248    * well currently, as it will just keep failing over and over.
1249    */
1250
1251   if (d->policy == NULL)
1252     {
1253       _dbus_verbose ("Failed to create security policy for connection %p\n",
1254                      connection);
1255       _DBUS_ASSERT_ERROR_IS_SET (error);
1256       dbus_free (d->name);
1257       d->name = NULL;
1258       return FALSE;
1259     }
1260
1261   if (dbus_connection_get_unix_user (connection, &uid))
1262     {
1263       if (!adjust_connections_for_uid (d->connections,
1264                                        uid, 1))
1265         {
1266           BUS_SET_OOM (error);
1267           dbus_free (d->name);
1268           d->name = NULL;
1269           return FALSE;
1270         }
1271     }
1272
1273   /* Now the connection is active, move it between lists */
1274   _dbus_list_unlink (&d->connections->incomplete,
1275                      d->link_in_connection_list);
1276   d->connections->n_incomplete -= 1;
1277   _dbus_list_append_link (&d->connections->completed,
1278                           d->link_in_connection_list);
1279   d->connections->n_completed += 1;
1280
1281   _dbus_assert (d->connections->n_incomplete >= 0);
1282   _dbus_assert (d->connections->n_completed > 0);
1283
1284   /* See if we can remove the timeout */
1285   bus_connections_expire_incomplete (d->connections);
1286
1287   _dbus_assert (bus_connection_is_active (connection));
1288
1289   return TRUE;
1290 }
1291
1292 const char *
1293 bus_connection_get_name (DBusConnection *connection)
1294 {
1295   BusConnectionData *d;
1296
1297   d = BUS_CONNECTION_DATA (connection);
1298   _dbus_assert (d != NULL);
1299
1300   return d->name;
1301 }
1302
1303 /**
1304  * Check whether completing the passed-in connection would
1305  * exceed limits, and if so set error and return #FALSE
1306  */
1307 dbus_bool_t
1308 bus_connections_check_limits (BusConnections  *connections,
1309                               DBusConnection  *requesting_completion,
1310                               DBusError       *error)
1311 {
1312   BusConnectionData *d;
1313   unsigned long uid;
1314
1315   d = BUS_CONNECTION_DATA (requesting_completion);
1316   _dbus_assert (d != NULL);
1317
1318   _dbus_assert (d->name == NULL);
1319
1320   if (connections->n_completed >=
1321       bus_context_get_max_completed_connections (connections->context))
1322     {
1323       dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
1324                       "The maximum number of active connections has been reached");
1325       return FALSE;
1326     }
1327
1328   if (dbus_connection_get_unix_user (requesting_completion, &uid))
1329     {
1330       if (get_connections_for_uid (connections, uid) >=
1331           bus_context_get_max_connections_per_user (connections->context))
1332         {
1333           dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
1334                           "The maximum number of active connections for UID %lu has been reached",
1335                           uid);
1336           return FALSE;
1337         }
1338     }
1339
1340   return TRUE;
1341 }
1342
1343 static dbus_bool_t
1344 bus_pending_reply_send_no_reply (BusConnections  *connections,
1345                                  BusTransaction  *transaction,
1346                                  BusPendingReply *pending)
1347 {
1348   DBusMessage *message;
1349   DBusMessageIter iter;
1350   dbus_bool_t retval;
1351
1352   retval = FALSE;
1353
1354   message = dbus_message_new (DBUS_MESSAGE_TYPE_ERROR);
1355   if (message == NULL)
1356     return FALSE;
1357
1358   dbus_message_set_no_reply (message, TRUE);
1359
1360   if (!dbus_message_set_reply_serial (message,
1361                                       pending->reply_serial))
1362     goto out;
1363
1364   if (!dbus_message_set_error_name (message,
1365                                     DBUS_ERROR_NO_REPLY))
1366     goto out;
1367
1368   dbus_message_append_iter_init (message, &iter);
1369   if (!dbus_message_iter_append_string (&iter, "Message did not receive a reply (timeout by message bus)"))
1370     goto out;
1371
1372   if (!bus_transaction_send_from_driver (transaction, pending->will_get_reply,
1373                                          message))
1374     goto out;
1375
1376   retval = TRUE;
1377
1378  out:
1379   dbus_message_unref (message);
1380   return retval;
1381 }
1382
1383 static void
1384 bus_pending_reply_expired (BusExpireList *list,
1385                            DBusList      *link,
1386                            void          *data)
1387 {
1388   BusPendingReply *pending = link->data;
1389   BusConnections *connections = data;
1390   BusTransaction *transaction;
1391
1392   /* No reply is forthcoming. So nuke it if we can. If not,
1393    * leave it in the list to try expiring again later when we
1394    * get more memory.
1395    */
1396   transaction = bus_transaction_new (connections->context);
1397   if (transaction == NULL)
1398     return;
1399
1400   if (bus_pending_reply_send_no_reply (connections,
1401                                        transaction,
1402                                        pending))
1403     {
1404       _dbus_list_remove_link (&connections->pending_replies->items,
1405                               link);
1406       dbus_free (pending);
1407       bus_transaction_cancel_and_free (transaction);
1408     }
1409
1410   bus_transaction_execute_and_free (transaction);
1411 }
1412
1413 static void
1414 bus_connection_drop_pending_replies (BusConnections  *connections,
1415                                      DBusConnection  *connection)
1416 {
1417   /* The DBusConnection is almost 100% finalized here, so you can't
1418    * do anything with it except check for pointer equality
1419    */
1420   DBusList *link;
1421
1422   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1423   while (link != NULL)
1424     {
1425       DBusList *next;
1426       BusPendingReply *pending;
1427
1428       next = _dbus_list_get_next_link (&connections->pending_replies->items,
1429                                        link);
1430       pending = link->data;
1431
1432       if (pending->will_get_reply == connection)
1433         {
1434           /* We don't need to track this pending reply anymore */
1435
1436           _dbus_list_remove_link (&connections->pending_replies->items,
1437                                   link);
1438           dbus_free (pending);
1439         }
1440       else if (pending->will_send_reply == connection)
1441         {
1442           /* The reply isn't going to be sent, so set things
1443            * up so it will be expired right away
1444            */
1445
1446           pending->will_send_reply = NULL;
1447           pending->expire_item.added_tv_sec = 0;
1448           pending->expire_item.added_tv_usec = 0;
1449
1450           bus_expire_timeout_set_interval (connections->pending_replies->timeout,
1451                                            0);
1452         }
1453
1454       link = next;
1455     }
1456 }
1457
1458
1459 typedef struct
1460 {
1461   BusPendingReply *pending;
1462   BusConnections  *connections;
1463 } CancelPendingReplyData;
1464
1465 static void
1466 cancel_pending_reply (void *data)
1467 {
1468   CancelPendingReplyData *d = data;
1469
1470   if (!_dbus_list_remove (&d->connections->pending_replies->items,
1471                           d->pending))
1472     _dbus_assert_not_reached ("pending reply did not exist to be cancelled");
1473
1474   dbus_free (d->pending); /* since it's been cancelled */
1475 }
1476
1477 static void
1478 cancel_pending_reply_data_free (void *data)
1479 {
1480   CancelPendingReplyData *d = data;
1481
1482   /* d->pending should be either freed or still
1483    * in the list of pending replies (owned by someone
1484    * else)
1485    */
1486
1487   dbus_free (d);
1488 }
1489
1490 /*
1491  * Record that a reply is allowed; return TRUE on success.
1492  */
1493 dbus_bool_t
1494 bus_connections_expect_reply (BusConnections  *connections,
1495                               BusTransaction  *transaction,
1496                               DBusConnection  *will_get_reply,
1497                               DBusConnection  *will_send_reply,
1498                               DBusMessage     *reply_to_this,
1499                               DBusError       *error)
1500 {
1501   BusPendingReply *pending;
1502   dbus_uint32_t reply_serial;
1503   DBusList *link;
1504   CancelPendingReplyData *cprd;
1505
1506   _dbus_assert (will_get_reply != NULL);
1507   _dbus_assert (will_send_reply != NULL);
1508   _dbus_assert (reply_to_this != NULL);
1509
1510   if (dbus_message_get_no_reply (reply_to_this))
1511     return TRUE; /* we won't allow a reply, since client doesn't care for one. */
1512
1513   reply_serial = dbus_message_get_serial (reply_to_this);
1514
1515   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1516   while (link != NULL)
1517     {
1518       pending = link->data;
1519
1520       if (pending->reply_serial == reply_serial &&
1521           pending->will_get_reply == will_get_reply &&
1522           pending->will_send_reply == will_send_reply)
1523         {
1524           dbus_set_error (error, DBUS_ERROR_ACCESS_DENIED,
1525                           "Message has the same reply serial as a currently-outstanding existing method call");
1526           return FALSE;
1527         }
1528
1529       link = _dbus_list_get_next_link (&connections->pending_replies->items,
1530                                        link);
1531     }
1532
1533   pending = dbus_new0 (BusPendingReply, 1);
1534   if (pending == NULL)
1535     {
1536       BUS_SET_OOM (error);
1537       return FALSE;
1538     }
1539
1540   cprd = dbus_new0 (CancelPendingReplyData, 1);
1541   if (cprd == NULL)
1542     {
1543       BUS_SET_OOM (error);
1544       dbus_free (pending);
1545       return FALSE;
1546     }
1547
1548   if (!_dbus_list_prepend (&connections->pending_replies->items,
1549                            pending))
1550     {
1551       BUS_SET_OOM (error);
1552       dbus_free (cprd);
1553       dbus_free (pending);
1554       return FALSE;
1555     }
1556
1557   if (!bus_transaction_add_cancel_hook (transaction,
1558                                         cancel_pending_reply,
1559                                         cprd,
1560                                         cancel_pending_reply_data_free))
1561     {
1562       BUS_SET_OOM (error);
1563       _dbus_list_remove (&connections->pending_replies->items, pending);
1564       dbus_free (cprd);
1565       dbus_free (pending);
1566       return FALSE;
1567     }
1568
1569   cprd->pending = pending;
1570   cprd->connections = connections;
1571
1572   _dbus_get_current_time (&pending->expire_item.added_tv_sec,
1573                           &pending->expire_item.added_tv_usec);
1574
1575   pending->will_get_reply = will_get_reply;
1576   pending->will_send_reply = will_send_reply;
1577   pending->reply_serial = reply_serial;
1578
1579   return TRUE;
1580 }
1581
1582 typedef struct
1583 {
1584   DBusList        *link;
1585   BusConnections  *connections;
1586 } CheckPendingReplyData;
1587
1588 static void
1589 cancel_check_pending_reply (void *data)
1590 {
1591   CheckPendingReplyData *d = data;
1592
1593   _dbus_list_prepend_link (&d->connections->pending_replies->items,
1594                            d->link);
1595   d->link = NULL;
1596 }
1597
1598 static void
1599 check_pending_reply_data_free (void *data)
1600 {
1601   CheckPendingReplyData *d = data;
1602
1603   if (d->link != NULL)
1604     {
1605       BusPendingReply *pending = d->link->data;
1606
1607       dbus_free (pending);
1608       _dbus_list_free_link (d->link);
1609     }
1610
1611   dbus_free (d);
1612 }
1613
1614 /*
1615  * Check whether a reply is allowed, remove BusPendingReply
1616  * if so, return TRUE if so.
1617  */
1618 dbus_bool_t
1619 bus_connections_check_reply (BusConnections *connections,
1620                              BusTransaction *transaction,
1621                              DBusConnection *sending_reply,
1622                              DBusConnection *receiving_reply,
1623                              DBusMessage    *reply,
1624                              DBusError      *error)
1625 {
1626   CheckPendingReplyData *cprd;
1627   DBusList *link;
1628   dbus_uint32_t reply_serial;
1629
1630   _dbus_assert (sending_reply != NULL);
1631   _dbus_assert (receiving_reply != NULL);
1632
1633   reply_serial = dbus_message_get_reply_serial (reply);
1634
1635   link = _dbus_list_get_first_link (&connections->pending_replies->items);
1636   while (link != NULL)
1637     {
1638       BusPendingReply *pending = link->data;
1639
1640       if (pending->reply_serial == reply_serial &&
1641           pending->will_get_reply == receiving_reply &&
1642           pending->will_send_reply == sending_reply)
1643         {
1644           _dbus_verbose ("Found pending reply\n");
1645           break;
1646         }
1647
1648       link = _dbus_list_get_next_link (&connections->pending_replies->items,
1649                                        link);
1650     }
1651
1652   if (link == NULL)
1653     {
1654       _dbus_verbose ("No pending reply expected\n");
1655
1656       return FALSE;
1657     }
1658
1659   cprd = dbus_new0 (CheckPendingReplyData, 1);
1660   if (cprd == NULL)
1661     {
1662       BUS_SET_OOM (error);
1663       return FALSE;
1664     }
1665
1666   if (!bus_transaction_add_cancel_hook (transaction,
1667                                         cancel_check_pending_reply,
1668                                         cprd,
1669                                         check_pending_reply_data_free))
1670     {
1671       BUS_SET_OOM (error);
1672       dbus_free (cprd);
1673       return FALSE;
1674     }
1675
1676   cprd->link = link;
1677   cprd->connections = connections;
1678
1679   _dbus_list_remove_link (&connections->pending_replies->items,
1680                           link);
1681
1682   return TRUE;
1683 }
1684
1685 /*
1686  * Transactions
1687  *
1688  * Note that this is fairly fragile; in particular, don't try to use
1689  * one transaction across any main loop iterations.
1690  */
1691
1692 typedef struct
1693 {
1694   BusTransaction *transaction;
1695   DBusMessage    *message;
1696   DBusPreallocatedSend *preallocated;
1697 } MessageToSend;
1698
1699 typedef struct
1700 {
1701   BusTransactionCancelFunction cancel_function;
1702   DBusFreeFunction free_data_function;
1703   void *data;
1704 } CancelHook;
1705
1706 struct BusTransaction
1707 {
1708   DBusList *connections;
1709   BusContext *context;
1710   DBusList *cancel_hooks;
1711 };
1712
1713 static void
1714 message_to_send_free (DBusConnection *connection,
1715                       MessageToSend  *to_send)
1716 {
1717   if (to_send->message)
1718     dbus_message_unref (to_send->message);
1719
1720   if (to_send->preallocated)
1721     dbus_connection_free_preallocated_send (connection, to_send->preallocated);
1722
1723   dbus_free (to_send);
1724 }
1725
1726 static void
1727 cancel_hook_cancel (void *element,
1728                     void *data)
1729 {
1730   CancelHook *ch = element;
1731
1732   _dbus_verbose ("Running transaction cancel hook\n");
1733
1734   if (ch->cancel_function)
1735     (* ch->cancel_function) (ch->data);
1736 }
1737
1738 static void
1739 cancel_hook_free (void *element,
1740                   void *data)
1741 {
1742   CancelHook *ch = element;
1743
1744   if (ch->free_data_function)
1745     (* ch->free_data_function) (ch->data);
1746
1747   dbus_free (ch);
1748 }
1749
1750 static void
1751 free_cancel_hooks (BusTransaction *transaction)
1752 {
1753   _dbus_list_foreach (&transaction->cancel_hooks,
1754                       cancel_hook_free, NULL);
1755
1756   _dbus_list_clear (&transaction->cancel_hooks);
1757 }
1758
1759 BusTransaction*
1760 bus_transaction_new (BusContext *context)
1761 {
1762   BusTransaction *transaction;
1763
1764   transaction = dbus_new0 (BusTransaction, 1);
1765   if (transaction == NULL)
1766     return NULL;
1767
1768   transaction->context = context;
1769
1770   return transaction;
1771 }
1772
1773 BusContext*
1774 bus_transaction_get_context (BusTransaction  *transaction)
1775 {
1776   return transaction->context;
1777 }
1778
1779 BusConnections*
1780 bus_transaction_get_connections (BusTransaction  *transaction)
1781 {
1782   return bus_context_get_connections (transaction->context);
1783 }
1784
1785 dbus_bool_t
1786 bus_transaction_send_from_driver (BusTransaction *transaction,
1787                                   DBusConnection *connection,
1788                                   DBusMessage    *message)
1789 {
1790   /* We have to set the sender to the driver, and have
1791    * to check security policy since it was not done in
1792    * dispatch.c
1793    */
1794   _dbus_verbose ("Sending %s %s %s from driver\n",
1795                  dbus_message_get_interface (message) ?
1796                  dbus_message_get_interface (message) : "(no interface)",
1797                  dbus_message_get_member (message) ?
1798                  dbus_message_get_member (message) : "(no member)",
1799                  dbus_message_get_error_name (message) ?
1800                  dbus_message_get_error_name (message) : "(no error name)");
1801
1802   if (!dbus_message_set_sender (message, DBUS_SERVICE_ORG_FREEDESKTOP_DBUS))
1803     return FALSE;
1804
1805   /* bus driver never wants a reply */
1806   dbus_message_set_no_reply (message, TRUE);
1807
1808   /* If security policy doesn't allow the message, we silently
1809    * eat it; the driver doesn't care about getting a reply.
1810    */
1811   if (!bus_context_check_security_policy (bus_transaction_get_context (transaction),
1812                                           transaction,
1813                                           NULL, connection, connection, message, NULL))
1814     return TRUE;
1815
1816   return bus_transaction_send (transaction, connection, message);
1817 }
1818
1819 dbus_bool_t
1820 bus_transaction_send (BusTransaction *transaction,
1821                       DBusConnection *connection,
1822                       DBusMessage    *message)
1823 {
1824   MessageToSend *to_send;
1825   BusConnectionData *d;
1826   DBusList *link;
1827
1828   _dbus_verbose ("  trying to add %s interface=%s member=%s error=%s to transaction%s\n",
1829                  dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_ERROR ? "error" :
1830                  dbus_message_get_reply_serial (message) != 0 ? "reply" :
1831                  "message",
1832                  dbus_message_get_interface (message) ?
1833                  dbus_message_get_interface (message) : "(unset)",
1834                  dbus_message_get_member (message) ?
1835                  dbus_message_get_member (message) : "(unset)",
1836                  dbus_message_get_error_name (message) ?
1837                  dbus_message_get_error_name (message) : "(unset)",
1838                  dbus_connection_get_is_connected (connection) ?
1839                  "" : " (disconnected)");
1840
1841   _dbus_assert (dbus_message_get_sender (message) != NULL);
1842
1843   if (!dbus_connection_get_is_connected (connection))
1844     return TRUE; /* silently ignore disconnected connections */
1845
1846   d = BUS_CONNECTION_DATA (connection);
1847   _dbus_assert (d != NULL);
1848
1849   to_send = dbus_new (MessageToSend, 1);
1850   if (to_send == NULL)
1851     {
1852       return FALSE;
1853     }
1854
1855   to_send->preallocated = dbus_connection_preallocate_send (connection);
1856   if (to_send->preallocated == NULL)
1857     {
1858       dbus_free (to_send);
1859       return FALSE;
1860     }
1861
1862   dbus_message_ref (message);
1863   to_send->message = message;
1864   to_send->transaction = transaction;
1865
1866   _dbus_verbose ("about to prepend message\n");
1867
1868   if (!_dbus_list_prepend (&d->transaction_messages, to_send))
1869     {
1870       message_to_send_free (connection, to_send);
1871       return FALSE;
1872     }
1873
1874   _dbus_verbose ("prepended message\n");
1875
1876   /* See if we already had this connection in the list
1877    * for this transaction. If we have a pending message,
1878    * then we should already be in transaction->connections
1879    */
1880   link = _dbus_list_get_first_link (&d->transaction_messages);
1881   _dbus_assert (link->data == to_send);
1882   link = _dbus_list_get_next_link (&d->transaction_messages, link);
1883   while (link != NULL)
1884     {
1885       MessageToSend *m = link->data;
1886       DBusList *next = _dbus_list_get_next_link (&d->transaction_messages, link);
1887
1888       if (m->transaction == transaction)
1889         break;
1890
1891       link = next;
1892     }
1893
1894   if (link == NULL)
1895     {
1896       if (!_dbus_list_prepend (&transaction->connections, connection))
1897         {
1898           _dbus_list_remove (&d->transaction_messages, to_send);
1899           message_to_send_free (connection, to_send);
1900           return FALSE;
1901         }
1902     }
1903
1904   return TRUE;
1905 }
1906
1907 static void
1908 connection_cancel_transaction (DBusConnection *connection,
1909                                BusTransaction *transaction)
1910 {
1911   DBusList *link;
1912   BusConnectionData *d;
1913
1914   d = BUS_CONNECTION_DATA (connection);
1915   _dbus_assert (d != NULL);
1916
1917   link = _dbus_list_get_first_link (&d->transaction_messages);
1918   while (link != NULL)
1919     {
1920       MessageToSend *m = link->data;
1921       DBusList *next = _dbus_list_get_next_link (&d->transaction_messages, link);
1922
1923       if (m->transaction == transaction)
1924         {
1925           _dbus_list_remove_link (&d->transaction_messages,
1926                                   link);
1927
1928           message_to_send_free (connection, m);
1929         }
1930
1931       link = next;
1932     }
1933 }
1934
1935 void
1936 bus_transaction_cancel_and_free (BusTransaction *transaction)
1937 {
1938   DBusConnection *connection;
1939
1940   _dbus_verbose ("TRANSACTION: cancelled\n");
1941
1942   while ((connection = _dbus_list_pop_first (&transaction->connections)))
1943     connection_cancel_transaction (connection, transaction);
1944
1945   _dbus_assert (transaction->connections == NULL);
1946
1947   _dbus_list_foreach (&transaction->cancel_hooks,
1948                       cancel_hook_cancel, NULL);
1949
1950   free_cancel_hooks (transaction);
1951
1952   dbus_free (transaction);
1953 }
1954
1955 static void
1956 connection_execute_transaction (DBusConnection *connection,
1957                                 BusTransaction *transaction)
1958 {
1959   DBusList *link;
1960   BusConnectionData *d;
1961
1962   d = BUS_CONNECTION_DATA (connection);
1963   _dbus_assert (d != NULL);
1964
1965   /* Send the queue in order (FIFO) */
1966   link = _dbus_list_get_last_link (&d->transaction_messages);
1967   while (link != NULL)
1968     {
1969       MessageToSend *m = link->data;
1970       DBusList *prev = _dbus_list_get_prev_link (&d->transaction_messages, link);
1971
1972       if (m->transaction == transaction)
1973         {
1974           _dbus_list_remove_link (&d->transaction_messages,
1975                                   link);
1976
1977           _dbus_assert (dbus_message_get_sender (m->message) != NULL);
1978
1979           dbus_connection_send_preallocated (connection,
1980                                              m->preallocated,
1981                                              m->message,
1982                                              NULL);
1983
1984           m->preallocated = NULL; /* so we don't double-free it */
1985
1986           message_to_send_free (connection, m);
1987         }
1988
1989       link = prev;
1990     }
1991 }
1992
1993 void
1994 bus_transaction_execute_and_free (BusTransaction *transaction)
1995 {
1996   /* For each connection in transaction->connections
1997    * send the messages
1998    */
1999   DBusConnection *connection;
2000
2001   _dbus_verbose ("TRANSACTION: executing\n");
2002
2003   while ((connection = _dbus_list_pop_first (&transaction->connections)))
2004     connection_execute_transaction (connection, transaction);
2005
2006   _dbus_assert (transaction->connections == NULL);
2007
2008   free_cancel_hooks (transaction);
2009
2010   dbus_free (transaction);
2011 }
2012
2013 static void
2014 bus_connection_remove_transactions (DBusConnection *connection)
2015 {
2016   MessageToSend *to_send;
2017   BusConnectionData *d;
2018
2019   d = BUS_CONNECTION_DATA (connection);
2020   _dbus_assert (d != NULL);
2021
2022   while ((to_send = _dbus_list_get_first (&d->transaction_messages)))
2023     {
2024       /* only has an effect for the first MessageToSend listing this transaction */
2025       _dbus_list_remove (&to_send->transaction->connections,
2026                          connection);
2027
2028       _dbus_list_remove (&d->transaction_messages, to_send);
2029       message_to_send_free (connection, to_send);
2030     }
2031 }
2032
2033 /**
2034  * Converts the DBusError to a message reply
2035  */
2036 dbus_bool_t
2037 bus_transaction_send_error_reply (BusTransaction  *transaction,
2038                                   DBusConnection  *connection,
2039                                   const DBusError *error,
2040                                   DBusMessage     *in_reply_to)
2041 {
2042   DBusMessage *reply;
2043
2044   _dbus_assert (error != NULL);
2045   _DBUS_ASSERT_ERROR_IS_SET (error);
2046
2047   _dbus_verbose ("Sending error reply %s \"%s\"\n",
2048                  error->name, error->message);
2049
2050   reply = dbus_message_new_error (in_reply_to,
2051                                   error->name,
2052                                   error->message);
2053   if (reply == NULL)
2054     return FALSE;
2055
2056   if (!bus_transaction_send_from_driver (transaction, connection, reply))
2057     {
2058       dbus_message_unref (reply);
2059       return FALSE;
2060     }
2061
2062   dbus_message_unref (reply);
2063
2064   return TRUE;
2065 }
2066
2067 dbus_bool_t
2068 bus_transaction_add_cancel_hook (BusTransaction               *transaction,
2069                                  BusTransactionCancelFunction  cancel_function,
2070                                  void                         *data,
2071                                  DBusFreeFunction              free_data_function)
2072 {
2073   CancelHook *ch;
2074
2075   ch = dbus_new (CancelHook, 1);
2076   if (ch == NULL)
2077     return FALSE;
2078
2079   ch->cancel_function = cancel_function;
2080   ch->data = data;
2081   ch->free_data_function = free_data_function;
2082
2083   /* It's important that the hooks get run in reverse order that they
2084    * were added
2085    */
2086   if (!_dbus_list_prepend (&transaction->cancel_hooks, ch))
2087     {
2088       dbus_free (ch);
2089       return FALSE;
2090     }
2091
2092   return TRUE;
2093 }