gio/gdbusnameowning.c

   1 /* GDBus - GLib D-Bus Library
   2  *
   3  * Copyright (C) 2008-2010 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Author: David Zeuthen <davidz@redhat.com>
  19  */
  20
  21 #include "config.h"
  22
  23 #include <stdlib.h>
  24
  25 #include "gdbusutils.h"
  26 #include "gdbusnameowning.h"
  27 #include "gdbuserror.h"
  28 #include "gdbusprivate.h"
  29 #include "gdbusconnection.h"
  30
  31 #include "glibintl.h"
  32
  33 /**
  34  * SECTION:gdbusnameowning
  35  * @title: Owning Bus Names
  36  * @short_description: Simple API for owning bus names
  37  * @include: gio/gio.h
  38  *
  39  * Convenience API for owning bus names.
  40  *
  41  * A simple example for owning a name can be found in
  42  * [gdbus-example-own-name.c](https://git.gnome.org/browse/glib/tree/gio/tests/gdbus-example-own-name.c)
  43  */
  44
  45 G_LOCK_DEFINE_STATIC (lock);
  46
  47 /* ---------------------------------------------------------------------------------------------------- */
  48
  49 typedef enum
  50 {
  51   PREVIOUS_CALL_NONE = 0,
  52   PREVIOUS_CALL_ACQUIRED,
  53   PREVIOUS_CALL_LOST,
  54 } PreviousCall;
  55
  56 typedef struct
  57 {
  58   volatile gint             ref_count;
  59   guint                     id;
  60   GBusNameOwnerFlags        flags;
  61   gchar                    *name;
  62   GBusAcquiredCallback      bus_acquired_handler;
  63   GBusNameAcquiredCallback  name_acquired_handler;
  64   GBusNameLostCallback      name_lost_handler;
  65   gpointer                  user_data;
  66   GDestroyNotify            user_data_free_func;
  67   GMainContext             *main_context;
  68
  69   PreviousCall              previous_call;
  70
  71   GDBusConnection          *connection;
  72   gulong                    disconnected_signal_handler_id;
  73   guint                     name_acquired_subscription_id;
  74   guint                     name_lost_subscription_id;
  75
  76   volatile gboolean         cancelled; /* must hold lock when reading or modifying */
  77
  78   gboolean                  needs_release;
  79 } Client;
  80
  81 static guint next_global_id = 1;
  82 static GHashTable *map_id_to_client = NULL;
  83
  84
  85 static Client *
  86 client_ref (Client *client)
  87 {
  88   g_atomic_int_inc (&client->ref_count);
  89   return client;
  90 }
  91
  92 static void
  93 client_unref (Client *client)
  94 {
  95   if (g_atomic_int_dec_and_test (&client->ref_count))
  96     {
  97       if (client->connection != NULL)
  98         {
  99           if (client->disconnected_signal_handler_id > 0)
 100             g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 101           if (client->name_acquired_subscription_id > 0)
 102             g_dbus_connection_signal_unsubscribe (client->connection, client->name_acquired_subscription_id);
 103           if (client->name_lost_subscription_id > 0)
 104             g_dbus_connection_signal_unsubscribe (client->connection, client->name_lost_subscription_id);
 105           g_object_unref (client->connection);
 106         }
 107       g_main_context_unref (client->main_context);
 108       g_free (client->name);
 109       if (client->user_data_free_func != NULL)
 110         client->user_data_free_func (client->user_data);
 111       g_free (client);
 112     }
 113 }
 114
 115 /* ---------------------------------------------------------------------------------------------------- */
 116
 117
 118 typedef enum
 119 {
 120   CALL_TYPE_NAME_ACQUIRED,
 121   CALL_TYPE_NAME_LOST
 122 } CallType;
 123
 124 typedef struct
 125 {
 126   Client *client;
 127
 128   /* keep this separate because client->connection may
 129    * be set to NULL after scheduling the call
 130    */
 131   GDBusConnection *connection;
 132
 133   /* set to TRUE to call acquired */
 134   CallType call_type;
 135 } CallHandlerData;
 136
 137 static void
 138 call_handler_data_free (CallHandlerData *data)
 139 {
 140   if (data->connection != NULL)
 141     g_object_unref (data->connection);
 142   client_unref (data->client);
 143   g_free (data);
 144 }
 145
 146 static void
 147 actually_do_call (Client *client, GDBusConnection *connection, CallType call_type)
 148 {
 149   switch (call_type)
 150     {
 151     case CALL_TYPE_NAME_ACQUIRED:
 152       if (client->name_acquired_handler != NULL)
 153         {
 154           client->name_acquired_handler (connection,
 155                                          client->name,
 156                                          client->user_data);
 157         }
 158       break;
 159
 160     case CALL_TYPE_NAME_LOST:
 161       if (client->name_lost_handler != NULL)
 162         {
 163           client->name_lost_handler (connection,
 164                                      client->name,
 165                                      client->user_data);
 166         }
 167       break;
 168
 169     default:
 170       g_assert_not_reached ();
 171       break;
 172     }
 173 }
 174
 175 static gboolean
 176 call_in_idle_cb (gpointer _data)
 177 {
 178   CallHandlerData *data = _data;
 179   actually_do_call (data->client, data->connection, data->call_type);
 180   return FALSE;
 181 }
 182
 183 static void
 184 schedule_call_in_idle (Client *client, CallType  call_type)
 185 {
 186   CallHandlerData *data;
 187   GSource *idle_source;
 188
 189   data = g_new0 (CallHandlerData, 1);
 190   data->client = client_ref (client);
 191   data->connection = client->connection != NULL ? g_object_ref (client->connection) : NULL;
 192   data->call_type = call_type;
 193
 194   idle_source = g_idle_source_new ();
 195   g_source_set_priority (idle_source, G_PRIORITY_HIGH);
 196   g_source_set_callback (idle_source,
 197                          call_in_idle_cb,
 198                          data,
 199                          (GDestroyNotify) call_handler_data_free);
 200   g_source_set_name (idle_source, "[gio, gdbusnameowning.c] call_in_idle_cb");
 201   g_source_attach (idle_source, client->main_context);
 202   g_source_unref (idle_source);
 203 }
 204
 205 static void
 206 do_call (Client *client, CallType call_type)
 207 {
 208   GMainContext *current_context;
 209
 210   /* only schedule in idle if we're not in the right thread */
 211   current_context = g_main_context_ref_thread_default ();
 212   if (current_context != client->main_context)
 213     schedule_call_in_idle (client, call_type);
 214   else
 215     actually_do_call (client, client->connection, call_type);
 216   g_main_context_unref (current_context);
 217 }
 218
 219 static void
 220 call_acquired_handler (Client *client)
 221 {
 222   G_LOCK (lock);
 223   if (client->previous_call != PREVIOUS_CALL_ACQUIRED)
 224     {
 225       client->previous_call = PREVIOUS_CALL_ACQUIRED;
 226       if (!client->cancelled)
 227         {
 228           G_UNLOCK (lock);
 229           do_call (client, CALL_TYPE_NAME_ACQUIRED);
 230           goto out;
 231         }
 232     }
 233   G_UNLOCK (lock);
 234  out:
 235   ;
 236 }
 237
 238 static void
 239 call_lost_handler (Client  *client)
 240 {
 241   G_LOCK (lock);
 242   if (client->previous_call != PREVIOUS_CALL_LOST)
 243     {
 244       client->previous_call = PREVIOUS_CALL_LOST;
 245       if (!client->cancelled)
 246         {
 247           G_UNLOCK (lock);
 248           do_call (client, CALL_TYPE_NAME_LOST);
 249           goto out;
 250         }
 251     }
 252   G_UNLOCK (lock);
 253  out:
 254   ;
 255 }
 256
 257 /* ---------------------------------------------------------------------------------------------------- */
 258
 259 static void
 260 on_name_lost_or_acquired (GDBusConnection  *connection,
 261                           const gchar      *sender_name,
 262                           const gchar      *object_path,
 263                           const gchar      *interface_name,
 264                           const gchar      *signal_name,
 265                           GVariant         *parameters,
 266                           gpointer          user_data)
 267 {
 268   Client *client = user_data;
 269   const gchar *name;
 270
 271   if (g_strcmp0 (object_path, "/org/freedesktop/DBus") != 0 ||
 272       g_strcmp0 (interface_name, "org.freedesktop.DBus") != 0 ||
 273       g_strcmp0 (sender_name, "org.freedesktop.DBus") != 0)
 274     goto out;
 275
 276   if (!g_variant_is_of_type (parameters, G_VARIANT_TYPE ("(s)")))
 277     {
 278       g_warning ("%s signal had unexpected signature %s", signal_name,
 279                  g_variant_get_type_string (parameters));
 280       goto out;
 281     }
 282
 283   if (g_strcmp0 (signal_name, "NameLost") == 0)
 284     {
 285       g_variant_get (parameters, "(&s)", &name);
 286       if (g_strcmp0 (name, client->name) == 0)
 287         {
 288           call_lost_handler (client);
 289         }
 290     }
 291   else if (g_strcmp0 (signal_name, "NameAcquired") == 0)
 292     {
 293       g_variant_get (parameters, "(&s)", &name);
 294       if (g_strcmp0 (name, client->name) == 0)
 295         {
 296           call_acquired_handler (client);
 297         }
 298     }
 299  out:
 300   ;
 301 }
 302
 303 /* ---------------------------------------------------------------------------------------------------- */
 304
 305 static void
 306 request_name_cb (GObject      *source_object,
 307                  GAsyncResult *res,
 308                  gpointer      user_data)
 309 {
 310   Client *client = user_data;
 311   GVariant *result;
 312   guint32 request_name_reply;
 313   gboolean unsubscribe;
 314
 315   request_name_reply = 0;
 316   result = NULL;
 317
 318   /* don't use client->connection - it may be NULL already */
 319   result = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
 320                                           res,
 321                                           NULL);
 322   if (result != NULL)
 323     {
 324       g_variant_get (result, "(u)", &request_name_reply);
 325       g_variant_unref (result);
 326     }
 327
 328   unsubscribe = FALSE;
 329
 330   switch (request_name_reply)
 331     {
 332     case 1: /* DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER */
 333       /* We got the name - now listen for NameLost and NameAcquired */
 334       call_acquired_handler (client);
 335       break;
 336
 337     case 2: /* DBUS_REQUEST_NAME_REPLY_IN_QUEUE */
 338       /* Waiting in line - listen for NameLost and NameAcquired */
 339       call_lost_handler (client);
 340       break;
 341
 342     default:
 343       /* assume we couldn't get the name - explicit fallthrough */
 344     case 3: /* DBUS_REQUEST_NAME_REPLY_EXISTS */
 345     case 4: /* DBUS_REQUEST_NAME_REPLY_ALREADY_OWNER */
 346       /* Some other part of the process is already owning the name */
 347       call_lost_handler (client);
 348       unsubscribe = TRUE;
 349       client->needs_release = FALSE;
 350       break;
 351     }
 352
 353   /* If we’re not the owner and not in the queue, there’s no point in continuing
 354    * to listen to NameAcquired or NameLost. */
 355   if (unsubscribe)
 356     {
 357       GDBusConnection *connection = NULL;
 358
 359       /* make sure we use a known good Connection object since it may be set to
 360        * NULL at any point after being cancelled
 361        */
 362       G_LOCK (lock);
 363       if (!client->cancelled)
 364         connection = g_object_ref (client->connection);
 365       G_UNLOCK (lock);
 366
 367       if (connection != NULL)
 368         {
 369           if (client->name_acquired_subscription_id > 0)
 370             g_dbus_connection_signal_unsubscribe (client->connection, client->name_acquired_subscription_id);
 371           if (client->name_lost_subscription_id > 0)
 372             g_dbus_connection_signal_unsubscribe (client->connection, client->name_lost_subscription_id);
 373           client->name_acquired_subscription_id = 0;
 374           client->name_lost_subscription_id = 0;
 375
 376           g_object_unref (connection);
 377         }
 378     }
 379
 380   client_unref (client);
 381 }
 382
 383 /* ---------------------------------------------------------------------------------------------------- */
 384
 385 static void
 386 on_connection_disconnected (GDBusConnection *connection,
 387                             gboolean         remote_peer_vanished,
 388                             GError          *error,
 389                             gpointer         user_data)
 390 {
 391   Client *client = user_data;
 392
 393   if (client->disconnected_signal_handler_id > 0)
 394     g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 395   if (client->name_acquired_subscription_id > 0)
 396     g_dbus_connection_signal_unsubscribe (client->connection, client->name_acquired_subscription_id);
 397   if (client->name_lost_subscription_id > 0)
 398     g_dbus_connection_signal_unsubscribe (client->connection, client->name_lost_subscription_id);
 399   g_object_unref (client->connection);
 400   client->disconnected_signal_handler_id = 0;
 401   client->name_acquired_subscription_id = 0;
 402   client->name_lost_subscription_id = 0;
 403   client->connection = NULL;
 404
 405   call_lost_handler (client);
 406 }
 407
 408 /* ---------------------------------------------------------------------------------------------------- */
 409
 410 static void
 411 has_connection (Client *client)
 412 {
 413   /* listen for disconnection */
 414   client->disconnected_signal_handler_id = g_signal_connect (client->connection,
 415                                                              "closed",
 416                                                              G_CALLBACK (on_connection_disconnected),
 417                                                              client);
 418
 419   /* Start listening to NameLost and NameAcquired messages. We hold
 420    * references to the Client in the signal closures, since it’s possible
 421    * for a signal to be in-flight after unsubscribing the signal handler.
 422    * This creates a reference count cycle, but that’s explicitly broken by
 423    * disconnecting the signal handlers before calling client_unref() in
 424    * g_bus_unown_name().
 425    *
 426    * Subscribe to NameLost and NameAcquired before calling RequestName() to
 427    * avoid the potential race of losing the name between receiving a reply to
 428    * RequestName() and subscribing to NameLost. The #PreviousCall state will
 429    * ensure that the user callbacks get called an appropriate number of times. */
 430   client->name_lost_subscription_id =
 431     g_dbus_connection_signal_subscribe (client->connection,
 432                                         "org.freedesktop.DBus",
 433                                         "org.freedesktop.DBus",
 434                                         "NameLost",
 435                                         "/org/freedesktop/DBus",
 436                                         client->name,
 437                                         G_DBUS_SIGNAL_FLAGS_NONE,
 438                                         on_name_lost_or_acquired,
 439                                         client_ref (client),
 440                                         (GDestroyNotify) client_unref);
 441   client->name_acquired_subscription_id =
 442     g_dbus_connection_signal_subscribe (client->connection,
 443                                         "org.freedesktop.DBus",
 444                                         "org.freedesktop.DBus",
 445                                         "NameAcquired",
 446                                         "/org/freedesktop/DBus",
 447                                         client->name,
 448                                         G_DBUS_SIGNAL_FLAGS_NONE,
 449                                         on_name_lost_or_acquired,
 450                                         client_ref (client),
 451                                         (GDestroyNotify) client_unref);
 452
 453   /* attempt to acquire the name */
 454   client->needs_release = TRUE;
 455   g_dbus_connection_call (client->connection,
 456                           "org.freedesktop.DBus",  /* bus name */
 457                           "/org/freedesktop/DBus", /* object path */
 458                           "org.freedesktop.DBus",  /* interface name */
 459                           "RequestName",           /* method name */
 460                           g_variant_new ("(su)",
 461                                          client->name,
 462                                          client->flags),
 463                           G_VARIANT_TYPE ("(u)"),
 464                           G_DBUS_CALL_FLAGS_NONE,
 465                           -1,
 466                           NULL,
 467                           (GAsyncReadyCallback) request_name_cb,
 468                           client_ref (client));
 469 }
 470
 471
 472 static void
 473 connection_get_cb (GObject      *source_object,
 474                    GAsyncResult *res,
 475                    gpointer      user_data)
 476 {
 477   Client *client = user_data;
 478
 479   /* must not do anything if already cancelled */
 480   G_LOCK (lock);
 481   if (client->cancelled)
 482     {
 483       G_UNLOCK (lock);
 484       goto out;
 485     }
 486   G_UNLOCK (lock);
 487
 488   client->connection = g_bus_get_finish (res, NULL);
 489   if (client->connection == NULL)
 490     {
 491       call_lost_handler (client);
 492       goto out;
 493     }
 494
 495   /* No need to schedule this in idle as we're already in the thread
 496    * that the user called g_bus_own_name() from. This is because
 497    * g_bus_get() guarantees that.
 498    *
 499    * Also, we need to ensure that the handler is invoked *before*
 500    * we call RequestName(). Otherwise there is a race.
 501    */
 502   if (client->bus_acquired_handler != NULL)
 503     {
 504       client->bus_acquired_handler (client->connection,
 505                                     client->name,
 506                                     client->user_data);
 507     }
 508
 509   has_connection (client);
 510
 511  out:
 512   client_unref (client);
 513 }
 514
 515 /* ---------------------------------------------------------------------------------------------------- */
 516
 517 /**
 518  * g_bus_own_name_on_connection:
 519  * @connection: a #GDBusConnection
 520  * @name: the well-known name to own
 521  * @flags: a set of flags from the #GBusNameOwnerFlags enumeration
 522  * @name_acquired_handler: (nullable): handler to invoke when @name is acquired or %NULL
 523  * @name_lost_handler: (nullable): handler to invoke when @name is lost or %NULL
 524  * @user_data: user data to pass to handlers
 525  * @user_data_free_func: (nullable): function for freeing @user_data or %NULL
 526  *
 527  * Like g_bus_own_name() but takes a #GDBusConnection instead of a
 528  * #GBusType.
 529  *
 530  * Returns: an identifier (never 0) that can be used with
 531  *     g_bus_unown_name() to stop owning the name
 532  *
 533  * Since: 2.26
 534  */
 535 guint
 536 g_bus_own_name_on_connection (GDBusConnection          *connection,
 537                               const gchar              *name,
 538                               GBusNameOwnerFlags        flags,
 539                               GBusNameAcquiredCallback  name_acquired_handler,
 540                               GBusNameLostCallback      name_lost_handler,
 541                               gpointer                  user_data,
 542                               GDestroyNotify            user_data_free_func)
 543 {
 544   Client *client;
 545
 546   g_return_val_if_fail (G_IS_DBUS_CONNECTION (connection), 0);
 547   g_return_val_if_fail (g_dbus_is_name (name) && !g_dbus_is_unique_name (name), 0);
 548
 549   G_LOCK (lock);
 550
 551   client = g_new0 (Client, 1);
 552   client->ref_count = 1;
 553   client->id = next_global_id++; /* TODO: uh oh, handle overflow */
 554   client->name = g_strdup (name);
 555   client->flags = flags;
 556   client->name_acquired_handler = name_acquired_handler;
 557   client->name_lost_handler = name_lost_handler;
 558   client->user_data = user_data;
 559   client->user_data_free_func = user_data_free_func;
 560   client->main_context = g_main_context_ref_thread_default ();
 561
 562   client->connection = g_object_ref (connection);
 563
 564   if (map_id_to_client == NULL)
 565     {
 566       map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal);
 567     }
 568   g_hash_table_insert (map_id_to_client,
 569                        GUINT_TO_POINTER (client->id),
 570                        client);
 571
 572   G_UNLOCK (lock);
 573
 574   has_connection (client);
 575
 576   return client->id;
 577 }
 578
 579 /**
 580  * g_bus_own_name:
 581  * @bus_type: the type of bus to own a name on
 582  * @name: the well-known name to own
 583  * @flags: a set of flags from the #GBusNameOwnerFlags enumeration
 584  * @bus_acquired_handler: (nullable): handler to invoke when connected to the bus of type @bus_type or %NULL
 585  * @name_acquired_handler: (nullable): handler to invoke when @name is acquired or %NULL
 586  * @name_lost_handler: (nullable): handler to invoke when @name is lost or %NULL
 587  * @user_data: user data to pass to handlers
 588  * @user_data_free_func: (nullable): function for freeing @user_data or %NULL
 589  *
 590  * Starts acquiring @name on the bus specified by @bus_type and calls
 591  * @name_acquired_handler and @name_lost_handler when the name is
 592  * acquired respectively lost. Callbacks will be invoked in the
 593  * [thread-default main context][g-main-context-push-thread-default]
 594  * of the thread you are calling this function from.
 595  *
 596  * You are guaranteed that one of the @name_acquired_handler and @name_lost_handler
 597  * callbacks will be invoked after calling this function - there are three
 598  * possible cases:
 599  *
 600  * - @name_lost_handler with a %NULL connection (if a connection to the bus
 601  *   can't be made).
 602  *
 603  * - @bus_acquired_handler then @name_lost_handler (if the name can't be
 604  *   obtained)
 605  *
 606  * - @bus_acquired_handler then @name_acquired_handler (if the name was
 607  *   obtained).
 608  *
 609  * When you are done owning the name, just call g_bus_unown_name()
 610  * with the owner id this function returns.
 611  *
 612  * If the name is acquired or lost (for example another application
 613  * could acquire the name if you allow replacement or the application
 614  * currently owning the name exits), the handlers are also invoked.
 615  * If the #GDBusConnection that is used for attempting to own the name
 616  * closes, then @name_lost_handler is invoked since it is no longer
 617  * possible for other processes to access the process.
 618  *
 619  * You cannot use g_bus_own_name() several times for the same name (unless
 620  * interleaved with calls to g_bus_unown_name()) - only the first call
 621  * will work.
 622  *
 623  * Another guarantee is that invocations of @name_acquired_handler
 624  * and @name_lost_handler are guaranteed to alternate; that
 625  * is, if @name_acquired_handler is invoked then you are
 626  * guaranteed that the next time one of the handlers is invoked, it
 627  * will be @name_lost_handler. The reverse is also true.
 628  *
 629  * If you plan on exporting objects (using e.g.
 630  * g_dbus_connection_register_object()), note that it is generally too late
 631  * to export the objects in @name_acquired_handler. Instead, you can do this
 632  * in @bus_acquired_handler since you are guaranteed that this will run
 633  * before @name is requested from the bus.
 634  *
 635  * This behavior makes it very simple to write applications that wants
 636  * to [own names][gdbus-owning-names] and export objects.
 637  * Simply register objects to be exported in @bus_acquired_handler and
 638  * unregister the objects (if any) in @name_lost_handler.
 639  *
 640  * Returns: an identifier (never 0) that can be used with
 641  *     g_bus_unown_name() to stop owning the name.
 642  *
 643  * Since: 2.26
 644  */
 645 guint
 646 g_bus_own_name (GBusType                  bus_type,
 647                 const gchar              *name,
 648                 GBusNameOwnerFlags        flags,
 649                 GBusAcquiredCallback      bus_acquired_handler,
 650                 GBusNameAcquiredCallback  name_acquired_handler,
 651                 GBusNameLostCallback      name_lost_handler,
 652                 gpointer                  user_data,
 653                 GDestroyNotify            user_data_free_func)
 654 {
 655   Client *client;
 656
 657   g_return_val_if_fail (g_dbus_is_name (name) && !g_dbus_is_unique_name (name), 0);
 658
 659   G_LOCK (lock);
 660
 661   client = g_new0 (Client, 1);
 662   client->ref_count = 1;
 663   client->id = next_global_id++; /* TODO: uh oh, handle overflow */
 664   client->name = g_strdup (name);
 665   client->flags = flags;
 666   client->bus_acquired_handler = bus_acquired_handler;
 667   client->name_acquired_handler = name_acquired_handler;
 668   client->name_lost_handler = name_lost_handler;
 669   client->user_data = user_data;
 670   client->user_data_free_func = user_data_free_func;
 671   client->main_context = g_main_context_ref_thread_default ();
 672
 673   if (map_id_to_client == NULL)
 674     {
 675       map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal);
 676     }
 677   g_hash_table_insert (map_id_to_client,
 678                        GUINT_TO_POINTER (client->id),
 679                        client);
 680
 681   g_bus_get (bus_type,
 682              NULL,
 683              connection_get_cb,
 684              client_ref (client));
 685
 686   G_UNLOCK (lock);
 687
 688   return client->id;
 689 }
 690
 691 typedef struct {
 692   GClosure *bus_acquired_closure;
 693   GClosure *name_acquired_closure;
 694   GClosure *name_lost_closure;
 695 } OwnNameData;
 696
 697 static OwnNameData *
 698 own_name_data_new (GClosure *bus_acquired_closure,
 699                    GClosure *name_acquired_closure,
 700                    GClosure *name_lost_closure)
 701 {
 702   OwnNameData *data;
 703
 704   data = g_new0 (OwnNameData, 1);
 705
 706   if (bus_acquired_closure != NULL)
 707     {
 708       data->bus_acquired_closure = g_closure_ref (bus_acquired_closure);
 709       g_closure_sink (bus_acquired_closure);
 710       if (G_CLOSURE_NEEDS_MARSHAL (bus_acquired_closure))
 711         g_closure_set_marshal (bus_acquired_closure, g_cclosure_marshal_generic);
 712     }
 713
 714   if (name_acquired_closure != NULL)
 715     {
 716       data->name_acquired_closure = g_closure_ref (name_acquired_closure);
 717       g_closure_sink (name_acquired_closure);
 718       if (G_CLOSURE_NEEDS_MARSHAL (name_acquired_closure))
 719         g_closure_set_marshal (name_acquired_closure, g_cclosure_marshal_generic);
 720     }
 721
 722   if (name_lost_closure != NULL)
 723     {
 724       data->name_lost_closure = g_closure_ref (name_lost_closure);
 725       g_closure_sink (name_lost_closure);
 726       if (G_CLOSURE_NEEDS_MARSHAL (name_lost_closure))
 727         g_closure_set_marshal (name_lost_closure, g_cclosure_marshal_generic);
 728     }
 729
 730   return data;
 731 }
 732
 733 static void
 734 own_with_closures_on_bus_acquired (GDBusConnection *connection,
 735                                    const gchar     *name,
 736                                    gpointer         user_data)
 737 {
 738   OwnNameData *data = user_data;
 739   GValue params[2] = { G_VALUE_INIT, G_VALUE_INIT };
 740
 741   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 742   g_value_set_object (&params[0], connection);
 743
 744   g_value_init (&params[1], G_TYPE_STRING);
 745   g_value_set_string (&params[1], name);
 746
 747   g_closure_invoke (data->bus_acquired_closure, NULL, 2, params, NULL);
 748
 749   g_value_unset (params + 0);
 750   g_value_unset (params + 1);
 751 }
 752
 753 static void
 754 own_with_closures_on_name_acquired (GDBusConnection *connection,
 755                                     const gchar     *name,
 756                                     gpointer         user_data)
 757 {
 758   OwnNameData *data = user_data;
 759   GValue params[2] = { G_VALUE_INIT, G_VALUE_INIT };
 760
 761   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 762   g_value_set_object (&params[0], connection);
 763
 764   g_value_init (&params[1], G_TYPE_STRING);
 765   g_value_set_string (&params[1], name);
 766
 767   g_closure_invoke (data->name_acquired_closure, NULL, 2, params, NULL);
 768
 769   g_value_unset (params + 0);
 770   g_value_unset (params + 1);
 771 }
 772
 773 static void
 774 own_with_closures_on_name_lost (GDBusConnection *connection,
 775                                 const gchar     *name,
 776                                 gpointer         user_data)
 777 {
 778   OwnNameData *data = user_data;
 779   GValue params[2] = { G_VALUE_INIT, G_VALUE_INIT };
 780
 781   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 782   g_value_set_object (&params[0], connection);
 783
 784   g_value_init (&params[1], G_TYPE_STRING);
 785   g_value_set_string (&params[1], name);
 786
 787   g_closure_invoke (data->name_lost_closure, NULL, 2, params, NULL);
 788
 789   g_value_unset (params + 0);
 790   g_value_unset (params + 1);
 791 }
 792
 793 static void
 794 bus_own_name_free_func (gpointer user_data)
 795 {
 796   OwnNameData *data = user_data;
 797
 798   if (data->bus_acquired_closure != NULL)
 799     g_closure_unref (data->bus_acquired_closure);
 800
 801   if (data->name_acquired_closure != NULL)
 802     g_closure_unref (data->name_acquired_closure);
 803
 804   if (data->name_lost_closure != NULL)
 805     g_closure_unref (data->name_lost_closure);
 806
 807   g_free (data);
 808 }
 809
 810 /**
 811  * g_bus_own_name_with_closures: (rename-to g_bus_own_name)
 812  * @bus_type: the type of bus to own a name on
 813  * @name: the well-known name to own
 814  * @flags: a set of flags from the #GBusNameOwnerFlags enumeration
 815  * @bus_acquired_closure: (nullable): #GClosure to invoke when connected to
 816  *     the bus of type @bus_type or %NULL
 817  * @name_acquired_closure: (nullable): #GClosure to invoke when @name is
 818  *     acquired or %NULL
 819  * @name_lost_closure: (nullable): #GClosure to invoke when @name is lost or
 820  *     %NULL
 821  *
 822  * Version of g_bus_own_name() using closures instead of callbacks for
 823  * easier binding in other languages.
 824  *
 825  * Returns: an identifier (never 0) that can be used with
 826  *     g_bus_unown_name() to stop owning the name.
 827  *
 828  * Since: 2.26
 829  */
 830 guint
 831 g_bus_own_name_with_closures (GBusType            bus_type,
 832                               const gchar        *name,
 833                               GBusNameOwnerFlags  flags,
 834                               GClosure           *bus_acquired_closure,
 835                               GClosure           *name_acquired_closure,
 836                               GClosure           *name_lost_closure)
 837 {
 838   return g_bus_own_name (bus_type,
 839           name,
 840           flags,
 841           bus_acquired_closure != NULL ? own_with_closures_on_bus_acquired : NULL,
 842           name_acquired_closure != NULL ? own_with_closures_on_name_acquired : NULL,
 843           name_lost_closure != NULL ? own_with_closures_on_name_lost : NULL,
 844           own_name_data_new (bus_acquired_closure,
 845                              name_acquired_closure,
 846                              name_lost_closure),
 847           bus_own_name_free_func);
 848 }
 849
 850 /**
 851  * g_bus_own_name_on_connection_with_closures: (rename-to g_bus_own_name_on_connection)
 852  * @connection: a #GDBusConnection
 853  * @name: the well-known name to own
 854  * @flags: a set of flags from the #GBusNameOwnerFlags enumeration
 855  * @name_acquired_closure: (nullable): #GClosure to invoke when @name is
 856  *     acquired or %NULL
 857  * @name_lost_closure: (nullable): #GClosure to invoke when @name is lost
 858  *     or %NULL
 859  *
 860  * Version of g_bus_own_name_on_connection() using closures instead of
 861  * callbacks for easier binding in other languages.
 862  *
 863  * Returns: an identifier (never 0) that can be used with
 864  *     g_bus_unown_name() to stop owning the name.
 865  *
 866  * Since: 2.26
 867  */
 868 guint
 869 g_bus_own_name_on_connection_with_closures (GDBusConnection    *connection,
 870                                             const gchar        *name,
 871                                             GBusNameOwnerFlags  flags,
 872                                             GClosure           *name_acquired_closure,
 873                                             GClosure           *name_lost_closure)
 874 {
 875   return g_bus_own_name_on_connection (connection,
 876           name,
 877           flags,
 878           name_acquired_closure != NULL ? own_with_closures_on_name_acquired : NULL,
 879           name_lost_closure != NULL ? own_with_closures_on_name_lost : NULL,
 880           own_name_data_new (NULL,
 881                              name_acquired_closure,
 882                              name_lost_closure),
 883           bus_own_name_free_func);
 884 }
 885
 886 /**
 887  * g_bus_unown_name:
 888  * @owner_id: an identifier obtained from g_bus_own_name()
 889  *
 890  * Stops owning a name.
 891  *
 892  * Note that there may still be D-Bus traffic to process (relating to owning
 893  * and unowning the name) in the current thread-default #GMainContext after
 894  * this function has returned. You should continue to iterate the #GMainContext
 895  * until the #GDestroyNotify function passed to g_bus_own_name() is called, in
 896  * order to avoid memory leaks through callbacks queued on the #GMainContext
 897  * after it’s stopped being iterated.
 898  *
 899  * Since: 2.26
 900  */
 901 void
 902 g_bus_unown_name (guint owner_id)
 903 {
 904   Client *client;
 905
 906   g_return_if_fail (owner_id > 0);
 907
 908   client = NULL;
 909
 910   G_LOCK (lock);
 911   if (owner_id == 0 || map_id_to_client == NULL ||
 912       (client = g_hash_table_lookup (map_id_to_client, GUINT_TO_POINTER (owner_id))) == NULL)
 913     {
 914       g_warning ("Invalid id %d passed to g_bus_unown_name()", owner_id);
 915       goto out;
 916     }
 917
 918   client->cancelled = TRUE;
 919   g_warn_if_fail (g_hash_table_remove (map_id_to_client, GUINT_TO_POINTER (owner_id)));
 920
 921  out:
 922   G_UNLOCK (lock);
 923
 924   /* do callback without holding lock */
 925   if (client != NULL)
 926     {
 927       /* Release the name if needed */
 928       if (client->needs_release &&
 929           client->connection != NULL &&
 930           !g_dbus_connection_is_closed (client->connection))
 931         {
 932           GVariant *result;
 933           GError *error;
 934           guint32 release_name_reply;
 935
 936           /* TODO: it kinda sucks having to do a sync call to release the name - but if
 937            * we don't, then a subsequent grab of the name will make the bus daemon return
 938            * IN_QUEUE which will trigger name_lost().
 939            *
 940            * I believe this is a bug in the bus daemon.
 941            */
 942           error = NULL;
 943           result = g_dbus_connection_call_sync (client->connection,
 944                                                 "org.freedesktop.DBus",  /* bus name */
 945                                                 "/org/freedesktop/DBus", /* object path */
 946                                                 "org.freedesktop.DBus",  /* interface name */
 947                                                 "ReleaseName",           /* method name */
 948                                                 g_variant_new ("(s)", client->name),
 949                                                 G_VARIANT_TYPE ("(u)"),
 950                                                 G_DBUS_CALL_FLAGS_NONE,
 951                                                 -1,
 952                                                 NULL,
 953                                                 &error);
 954           if (result == NULL)
 955             {
 956               g_warning ("Error releasing name %s: %s", client->name, error->message);
 957               g_error_free (error);
 958             }
 959           else
 960             {
 961               g_variant_get (result, "(u)", &release_name_reply);
 962               if (release_name_reply != 1 /* DBUS_RELEASE_NAME_REPLY_RELEASED */)
 963                 {
 964                   g_warning ("Unexpected reply %d when releasing name %s", release_name_reply, client->name);
 965                 }
 966               else
 967                 {
 968                   client->needs_release = FALSE;
 969                 }
 970               g_variant_unref (result);
 971             }
 972         }
 973
 974       if (client->disconnected_signal_handler_id > 0)
 975         g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 976       if (client->name_acquired_subscription_id > 0)
 977         g_dbus_connection_signal_unsubscribe (client->connection, client->name_acquired_subscription_id);
 978       if (client->name_lost_subscription_id > 0)
 979         g_dbus_connection_signal_unsubscribe (client->connection, client->name_lost_subscription_id);
 980       client->disconnected_signal_handler_id = 0;
 981       client->name_acquired_subscription_id = 0;
 982       client->name_lost_subscription_id = 0;
 983       if (client->connection != NULL)
 984         {
 985           g_object_unref (client->connection);
 986           client->connection = NULL;
 987         }
 988
 989       client_unref (client);
 990     }
 991 }