1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-bus.c Convenience functions for communicating with the bus.
4 * Copyright (C) 2003 CodeFactory AB
5 * Copyright (C) 2003 Red Hat, Inc.
7 * Licensed under the Academic Free License version 2.1
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27 #include "dbus-protocol.h"
28 #include "dbus-internals.h"
29 #include "dbus-message.h"
30 #include "dbus-marshal-validate.h"
31 #include "dbus-misc.h"
32 #include "dbus-threads-internal.h"
33 #include "dbus-connection-internal.h"
34 #include "dbus-string.h"
37 * @defgroup DBusBus Message bus APIs
39 * @brief Functions for communicating with the message bus
41 * dbus_bus_get() allows all modules and libraries in a given
42 * process to share the same connection to the bus daemon by storing
43 * the connection globally.
45 * All other functions in this module are just convenience functions;
46 * most of them invoke methods on the bus daemon, by sending method
47 * call messages to #DBUS_SERVICE_DBUS. These convenience functions
48 * often make blocking method calls. If you don't want to block,
49 * you can send the method call messages manually in the same way
50 * you would any other method call message.
52 * This module is the only one in libdbus that's specific to
53 * communicating with the message bus daemon. The rest of the API can
54 * also be used for connecting to another application directly.
56 * @todo right now the default address of the system bus is hardcoded,
57 * so if you change it in the global config file suddenly you have to
58 * set DBUS_SYSTEM_BUS_ADDRESS env variable. Might be nice if the
59 * client lib somehow read the config file, or if the bus on startup
60 * somehow wrote out its address to a well-known spot, but might also
65 * @defgroup DBusBusInternals Message bus APIs internals
66 * @ingroup DBusInternals
67 * @brief Internals of functions for communicating with the message bus
73 * Block of message-bus-related data we attach to each
74 * #DBusConnection used with these convenience functions.
79 DBusConnection *connection; /**< Connection we're associated with */
80 char *unique_name; /**< Unique name of this connection */
82 unsigned int is_well_known : 1; /**< Is one of the well-known connections in our global array */
85 /** The slot we have reserved to store BusData.
87 static dbus_int32_t bus_data_slot = -1;
89 /** Number of bus types */
92 static DBusConnection *bus_connections[N_BUS_TYPES];
93 static char *bus_connection_addresses[N_BUS_TYPES] = { NULL, NULL, NULL };
95 static DBusBusType activation_bus_type = DBUS_BUS_STARTER;
97 static dbus_bool_t initialized = FALSE;
100 addresses_shutdown_func (void *data)
105 while (i < N_BUS_TYPES)
107 if (bus_connections[i] != NULL)
108 _dbus_warn_check_failed ("dbus_shutdown() called but connections were still live. This probably means the application did not drop all its references to bus connections.");
110 dbus_free (bus_connection_addresses[i]);
111 bus_connection_addresses[i] = NULL;
115 activation_bus_type = DBUS_BUS_STARTER;
121 get_from_env (char **connection_p,
126 _dbus_assert (*connection_p == NULL);
128 s = _dbus_getenv (env_var);
129 if (s == NULL || *s == '\0')
130 return TRUE; /* successfully didn't use the env var */
133 *connection_p = _dbus_strdup (s);
134 return *connection_p != NULL;
139 init_session_address (void)
145 /* First, look in the environment. This is the normal case on
146 * freedesktop.org/Unix systems. */
147 get_from_env (&bus_connection_addresses[DBUS_BUS_SESSION],
148 "DBUS_SESSION_BUS_ADDRESS");
149 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
151 dbus_bool_t supported;
153 DBusError error = DBUS_ERROR_INIT;
155 if (!_dbus_string_init (&addr))
159 /* So it's not in the environment - let's try a platform-specific method.
160 * On MacOS, this involves asking launchd. On Windows (not specified yet)
161 * we might do a COM lookup.
162 * Ignore errors - if we failed, fall back to autolaunch. */
163 retval = _dbus_lookup_session_address (&supported, &addr, &error);
164 if (supported && retval)
166 retval =_dbus_string_steal_data (&addr, &bus_connection_addresses[DBUS_BUS_SESSION]);
168 else if (supported && !retval)
170 if (dbus_error_is_set(&error))
171 _dbus_warn ("Dynamic session lookup supported but failed: %s", error.message);
173 _dbus_warn ("Dynamic session lookup supported but failed silently");
175 _dbus_string_free (&addr);
183 /* We have a hard-coded (but compile-time-configurable) fallback address for
184 * the session bus. */
185 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
186 bus_connection_addresses[DBUS_BUS_SESSION] =
187 _dbus_strdup (DBUS_SESSION_BUS_CONNECT_ADDRESS);
189 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
196 init_connections_unlocked (void)
204 while (i < N_BUS_TYPES)
206 bus_connections[i] = NULL;
210 /* Don't init these twice, we may run this code twice if
211 * init_connections_unlocked() fails midway through.
212 * In practice, each block below should contain only one
213 * "return FALSE" or running through twice may not
217 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
219 _dbus_verbose ("Filling in system bus address...\n");
221 if (!get_from_env (&bus_connection_addresses[DBUS_BUS_SYSTEM],
222 "DBUS_SYSTEM_BUS_ADDRESS"))
227 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
229 /* Use default system bus address if none set in environment */
230 bus_connection_addresses[DBUS_BUS_SYSTEM] =
231 _dbus_strdup (DBUS_SYSTEM_BUS_DEFAULT_ADDRESS);
233 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
236 _dbus_verbose (" used default system bus \"%s\"\n",
237 bus_connection_addresses[DBUS_BUS_SYSTEM]);
240 _dbus_verbose (" used env var system bus \"%s\"\n",
241 bus_connection_addresses[DBUS_BUS_SYSTEM]);
243 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
245 _dbus_verbose ("Filling in session bus address...\n");
247 if (!init_session_address ())
250 _dbus_verbose (" \"%s\"\n", bus_connection_addresses[DBUS_BUS_SESSION] ?
251 bus_connection_addresses[DBUS_BUS_SESSION] : "none set");
254 if (bus_connection_addresses[DBUS_BUS_STARTER] == NULL)
256 _dbus_verbose ("Filling in activation bus address...\n");
258 if (!get_from_env (&bus_connection_addresses[DBUS_BUS_STARTER],
259 "DBUS_STARTER_ADDRESS"))
262 _dbus_verbose (" \"%s\"\n", bus_connection_addresses[DBUS_BUS_STARTER] ?
263 bus_connection_addresses[DBUS_BUS_STARTER] : "none set");
267 if (bus_connection_addresses[DBUS_BUS_STARTER] != NULL)
269 s = _dbus_getenv ("DBUS_STARTER_BUS_TYPE");
273 _dbus_verbose ("Bus activation type was set to \"%s\"\n", s);
275 if (strcmp (s, "system") == 0)
276 activation_bus_type = DBUS_BUS_SYSTEM;
277 else if (strcmp (s, "session") == 0)
278 activation_bus_type = DBUS_BUS_SESSION;
283 /* Default to the session bus instead if available */
284 if (bus_connection_addresses[DBUS_BUS_SESSION] != NULL)
286 bus_connection_addresses[DBUS_BUS_STARTER] =
287 _dbus_strdup (bus_connection_addresses[DBUS_BUS_SESSION]);
288 if (bus_connection_addresses[DBUS_BUS_STARTER] == NULL)
293 s = _dbus_getenv ("DBUS_DEFAULT_PROTOCOL_STRATEGY");
297 dbus_set_default_protocol_strategy (s);
300 /* If we return FALSE we have to be sure that restarting
301 * the above code will work right
304 if (!_dbus_register_shutdown_func (addresses_shutdown_func,
315 bus_data_free (void *data)
319 if (bd->is_well_known)
323 if (!_DBUS_LOCK (bus))
324 _dbus_assert_not_reached ("global locks should have been initialized "
325 "when we attached bus data");
327 /* We may be stored in more than one slot */
328 /* This should now be impossible - these slots are supposed to
329 * be cleared on disconnect, so should not need to be cleared on
333 while (i < N_BUS_TYPES)
335 if (bus_connections[i] == bd->connection)
336 bus_connections[i] = NULL;
343 dbus_free (bd->unique_name);
346 dbus_connection_free_data_slot (&bus_data_slot);
350 ensure_bus_data (DBusConnection *connection)
354 if (!dbus_connection_allocate_data_slot (&bus_data_slot))
357 bd = dbus_connection_get_data (connection, bus_data_slot);
360 bd = dbus_new0 (BusData, 1);
363 dbus_connection_free_data_slot (&bus_data_slot);
367 bd->connection = connection;
369 if (!dbus_connection_set_data (connection, bus_data_slot, bd,
373 dbus_connection_free_data_slot (&bus_data_slot);
377 /* Data slot refcount now held by the BusData */
381 dbus_connection_free_data_slot (&bus_data_slot);
388 * Internal function that checks to see if this
389 * is a shared connection owned by the bus and if it is unref it.
391 * @param connection a connection that has been disconnected.
394 _dbus_bus_notify_shared_connection_disconnected_unlocked (DBusConnection *connection)
398 if (!_DBUS_LOCK (bus))
400 /* If it was in bus_connections, we would have initialized global locks
401 * when we added it. So, it can't be. */
405 /* We are expecting to have the connection saved in only one of these
406 * slots, but someone could in a pathological case set system and session
407 * bus to the same bus or something. Or set one of them to the starter
408 * bus without setting the starter bus type in the env variable.
409 * So we don't break the loop as soon as we find a match.
411 for (i = 0; i < N_BUS_TYPES; ++i)
413 if (bus_connections[i] == connection)
415 bus_connections[i] = NULL;
422 static DBusConnection *
423 internal_bus_get (DBusBusType type,
428 DBusConnection *connection;
430 DBusBusType address_type;
432 _dbus_return_val_if_fail (type >= 0 && type < N_BUS_TYPES, NULL);
433 _dbus_return_val_if_error_is_set (error, NULL);
437 if (!_DBUS_LOCK (bus))
439 _DBUS_SET_OOM (error);
440 /* do not "goto out", that would try to unlock */
444 if (!init_connections_unlocked ())
446 _DBUS_SET_OOM (error);
450 /* We want to use the activation address even if the
451 * activating bus is the session or system bus,
456 /* Use the real type of the activation bus for getting its
457 * connection, but only if the real type's address is available. (If
458 * the activating bus isn't a well-known bus then
459 * activation_bus_type == DBUS_BUS_STARTER)
461 if (type == DBUS_BUS_STARTER &&
462 bus_connection_addresses[activation_bus_type] != NULL)
463 type = activation_bus_type;
465 if (!private && bus_connections[type] != NULL)
467 connection = bus_connections[type];
468 dbus_connection_ref (connection);
472 address = bus_connection_addresses[address_type];
475 dbus_set_error (error, DBUS_ERROR_FAILED,
476 "Unable to determine the address of the message bus (try 'man dbus-launch' and 'man dbus-daemon' for help)");
481 connection = dbus_connection_open_private (address, error);
483 connection = dbus_connection_open (address, error);
490 if (!dbus_bus_register (connection, error))
492 _dbus_connection_close_possibly_shared (connection);
493 dbus_connection_unref (connection);
500 /* store a weak ref to the connection (dbus-connection.c is
501 * supposed to have a strong ref that it drops on disconnect,
502 * since this is a shared connection)
504 bus_connections[type] = connection;
507 /* By default we're bound to the lifecycle of
510 dbus_connection_set_exit_on_disconnect (connection,
513 if (!_DBUS_LOCK (bus_datas))
514 _dbus_assert_not_reached ("global locks were initialized already");
516 bd = ensure_bus_data (connection);
517 _dbus_assert (bd != NULL); /* it should have been created on
518 register, so OOM not possible */
519 bd->is_well_known = TRUE;
520 _DBUS_UNLOCK (bus_datas);
523 /* Return a reference to the caller, or NULL with error set. */
524 if (connection == NULL)
525 _DBUS_ASSERT_ERROR_IS_SET (error);
532 /** @} */ /* end of implementation details docs */
535 * @addtogroup DBusBus
540 * Connects to a bus daemon and registers the client with it. If a
541 * connection to the bus already exists, then that connection is
542 * returned. The caller of this function owns a reference to the bus.
544 * The caller may NOT call dbus_connection_close() on this connection;
545 * see dbus_connection_open() and dbus_connection_close() for details
548 * If this function obtains a new connection object never before
549 * returned from dbus_bus_get(), it will call
550 * dbus_connection_set_exit_on_disconnect(), so the application
551 * will exit if the connection closes. You can undo this
552 * by calling dbus_connection_set_exit_on_disconnect() yourself
553 * after you get the connection.
555 * dbus_bus_get() calls dbus_bus_register() for you.
557 * If returning a newly-created connection, this function will block
558 * until authentication and bus registration are complete.
560 * @param type bus type
561 * @param error address where an error can be returned.
562 * @returns a #DBusConnection with new ref or #NULL on error
565 dbus_bus_get (DBusBusType type,
568 return internal_bus_get (type, FALSE, error);
572 * Connects to a bus daemon and registers the client with it as with
573 * dbus_bus_register(). Unlike dbus_bus_get(), always creates a new
574 * connection. This connection will not be saved or recycled by
575 * libdbus. Caller owns a reference to the bus and must either close
576 * it or know it to be closed prior to releasing this reference.
578 * See dbus_connection_open_private() for more details on when to
579 * close and unref this connection.
581 * This function calls
582 * dbus_connection_set_exit_on_disconnect() on the new connection, so the application
583 * will exit if the connection closes. You can undo this
584 * by calling dbus_connection_set_exit_on_disconnect() yourself
585 * after you get the connection.
587 * dbus_bus_get_private() calls dbus_bus_register() for you.
589 * This function will block until authentication and bus registration
592 * @param type bus type
593 * @param error address where an error can be returned.
594 * @returns a DBusConnection with new ref
597 dbus_bus_get_private (DBusBusType type,
600 return internal_bus_get (type, TRUE, error);
604 * Registers a connection with the bus. This must be the first
605 * thing an application does when connecting to the message bus.
606 * If registration succeeds, the unique name will be set,
607 * and can be obtained using dbus_bus_get_unique_name().
609 * This function will block until registration is complete.
611 * If the connection has already registered with the bus
612 * (determined by checking whether dbus_bus_get_unique_name()
613 * returns a non-#NULL value), then this function does nothing.
615 * If you use dbus_bus_get() or dbus_bus_get_private() this
616 * function will be called for you.
618 * @note Just use dbus_bus_get() or dbus_bus_get_private() instead of
619 * dbus_bus_register() and save yourself some pain. Using
620 * dbus_bus_register() manually is only useful if you have your
621 * own custom message bus not found in #DBusBusType.
623 * If you open a bus connection with dbus_connection_open() or
624 * dbus_connection_open_private() you will have to dbus_bus_register()
625 * yourself, or make the appropriate registration method calls
626 * yourself. If you send the method calls yourself, call
627 * dbus_bus_set_unique_name() with the unique bus name you get from
630 * For shared connections (created with dbus_connection_open()) in a
631 * multithreaded application, you can't really make the registration
632 * calls yourself, because you don't know whether some other thread is
633 * also registering, and the bus will kick you off if you send two
634 * registration messages.
636 * If you use dbus_bus_register() however, there is a lock that
637 * keeps both apps from registering at the same time.
639 * The rule in a multithreaded app, then, is that dbus_bus_register()
640 * must be used to register, or you need to have your own locks that
641 * all threads in the app will respect.
643 * In a single-threaded application you can register by hand instead
644 * of using dbus_bus_register(), as long as you check
645 * dbus_bus_get_unique_name() to see if a unique name has already been
646 * stored by another thread before you send the registration messages.
648 * @param connection the connection
649 * @param error place to store errors
650 * @returns #TRUE on success
653 dbus_bus_register (DBusConnection *connection,
656 DBusMessage *message, *reply;
661 _dbus_return_val_if_fail (connection != NULL, FALSE);
662 _dbus_return_val_if_error_is_set (error, FALSE);
668 if (!_DBUS_LOCK (bus_datas))
670 _DBUS_SET_OOM (error);
671 /* do not "goto out", that would try to unlock */
675 bd = ensure_bus_data (connection);
678 _DBUS_SET_OOM (error);
682 if (bd->unique_name != NULL)
684 _dbus_verbose ("Ignoring attempt to register the same DBusConnection %s with the message bus a second time.\n",
691 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
698 _DBUS_SET_OOM (error);
702 reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
706 else if (dbus_set_error_from_message (error, reply))
708 else if (!dbus_message_get_args (reply, error,
709 DBUS_TYPE_STRING, &name,
713 bd->unique_name = _dbus_strdup (name);
714 if (bd->unique_name == NULL)
716 _DBUS_SET_OOM (error);
723 _DBUS_UNLOCK (bus_datas);
726 dbus_message_unref (message);
729 dbus_message_unref (reply);
732 _DBUS_ASSERT_ERROR_IS_SET (error);
739 * Sets the unique name of the connection, as assigned by the message
740 * bus. Can only be used if you registered with the bus manually
741 * (i.e. if you did not call dbus_bus_register()). Can only be called
742 * once per connection. After the unique name is set, you can get it
743 * with dbus_bus_get_unique_name().
745 * The only reason to use this function is to re-implement the
746 * equivalent of dbus_bus_register() yourself. One (probably unusual)
747 * reason to do that might be to do the bus registration call
748 * asynchronously instead of synchronously.
750 * @note Just use dbus_bus_get() or dbus_bus_get_private(), or worst
751 * case dbus_bus_register(), instead of messing with this
752 * function. There's really no point creating pain for yourself by
753 * doing things manually.
755 * It's hard to use this function safely on shared connections
756 * (created by dbus_connection_open()) in a multithreaded application,
757 * because only one registration attempt can be sent to the bus. If
758 * two threads are both sending the registration message, there is no
759 * mechanism in libdbus itself to avoid sending it twice.
761 * Thus, you need a way to coordinate which thread sends the
762 * registration attempt; which also means you know which thread
763 * will call dbus_bus_set_unique_name(). If you don't know
764 * about all threads in the app (for example, if some libraries
765 * you're using might start libdbus-using threads), then you
766 * need to avoid using this function on shared connections.
768 * @param connection the connection
769 * @param unique_name the unique name
770 * @returns #FALSE if not enough memory
773 dbus_bus_set_unique_name (DBusConnection *connection,
774 const char *unique_name)
777 dbus_bool_t success = FALSE;
779 _dbus_return_val_if_fail (connection != NULL, FALSE);
780 _dbus_return_val_if_fail (unique_name != NULL, FALSE);
782 if (!_DBUS_LOCK (bus_datas))
784 /* do not "goto out", that would try to unlock */
788 bd = ensure_bus_data (connection);
792 _dbus_assert (bd->unique_name == NULL);
794 bd->unique_name = _dbus_strdup (unique_name);
795 success = bd->unique_name != NULL;
798 _DBUS_UNLOCK (bus_datas);
804 * Gets the unique name of the connection as assigned by the message
805 * bus. Only possible after the connection has been registered with
806 * the message bus. All connections returned by dbus_bus_get() or
807 * dbus_bus_get_private() have been successfully registered.
809 * The name remains valid until the connection is freed, and
810 * should not be freed by the caller.
812 * Other than dbus_bus_get(), there are two ways to set the unique
813 * name; one is dbus_bus_register(), the other is
814 * dbus_bus_set_unique_name(). You are responsible for calling
815 * dbus_bus_set_unique_name() if you register by hand instead of using
816 * dbus_bus_register().
818 * @param connection the connection
819 * @returns the unique name or #NULL on error
822 dbus_bus_get_unique_name (DBusConnection *connection)
825 const char *unique_name = NULL;
827 _dbus_return_val_if_fail (connection != NULL, NULL);
829 if (!_DBUS_LOCK (bus_datas))
831 /* We'd have initialized locks when we gave it its unique name, if it
832 * had one. Don't "goto out", that would try to unlock. */
836 bd = ensure_bus_data (connection);
840 unique_name = bd->unique_name;
843 _DBUS_UNLOCK (bus_datas);
849 * Asks the bus to return the UID the named connection authenticated
850 * as, if any. Only works on UNIX; only works for connections on the
851 * same machine as the bus. If you are not on the same machine as the
852 * bus, then calling this is probably a bad idea, since the UID will
853 * mean little to your application.
855 * For the system message bus you're guaranteed to be on the same
856 * machine since it only listens on a UNIX domain socket (at least,
857 * as shipped by default).
859 * This function only works for connections that authenticated as
860 * a UNIX user, right now that includes all bus connections, but
861 * it's very possible to have connections with no associated UID.
862 * So check for errors and do something sensible if they happen.
864 * This function will always return an error on Windows.
866 * @param connection the connection
867 * @param name a name owned by the connection
868 * @param error location to store the error
869 * @returns the unix user id, or ((unsigned)-1) if error is set
872 dbus_bus_get_unix_user (DBusConnection *connection,
876 DBusMessage *message, *reply;
879 _dbus_return_val_if_fail (connection != NULL, DBUS_UID_UNSET);
880 _dbus_return_val_if_fail (name != NULL, DBUS_UID_UNSET);
881 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), DBUS_UID_UNSET);
882 _dbus_return_val_if_error_is_set (error, DBUS_UID_UNSET);
884 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
887 "GetConnectionUnixUser");
891 _DBUS_SET_OOM (error);
892 return DBUS_UID_UNSET;
895 if (!dbus_message_append_args (message,
896 DBUS_TYPE_STRING, &name,
899 dbus_message_unref (message);
900 _DBUS_SET_OOM (error);
901 return DBUS_UID_UNSET;
904 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
907 dbus_message_unref (message);
911 _DBUS_ASSERT_ERROR_IS_SET (error);
912 return DBUS_UID_UNSET;
915 if (dbus_set_error_from_message (error, reply))
917 _DBUS_ASSERT_ERROR_IS_SET (error);
918 dbus_message_unref (reply);
919 return DBUS_UID_UNSET;
922 if (!dbus_message_get_args (reply, error,
923 DBUS_TYPE_UINT32, &uid,
926 _DBUS_ASSERT_ERROR_IS_SET (error);
927 dbus_message_unref (reply);
928 return DBUS_UID_UNSET;
931 dbus_message_unref (reply);
933 return (unsigned long) uid;
937 * Asks the bus to return its globally unique ID, as described in the
938 * D-Bus specification. For the session bus, this is useful as a way
939 * to uniquely identify each user session. For the system bus,
940 * probably the bus ID is not useful; instead, use the machine ID
941 * since it's accessible without necessarily connecting to the bus and
942 * may be persistent beyond a single bus instance (across reboots for
943 * example). See dbus_try_get_local_machine_id().
945 * In addition to an ID for each bus and an ID for each machine, there is
946 * an ID for each address that the bus is listening on; that can
947 * be retrieved with dbus_connection_get_server_id(), though it is
948 * probably not very useful.
950 * @param connection the connection
951 * @param error location to store the error
952 * @returns the bus ID or #NULL if error is set
955 dbus_bus_get_id (DBusConnection *connection,
958 DBusMessage *message, *reply;
960 const char *v_STRING;
962 _dbus_return_val_if_fail (connection != NULL, NULL);
963 _dbus_return_val_if_error_is_set (error, NULL);
965 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
972 _DBUS_SET_OOM (error);
976 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
979 dbus_message_unref (message);
983 _DBUS_ASSERT_ERROR_IS_SET (error);
987 if (dbus_set_error_from_message (error, reply))
989 _DBUS_ASSERT_ERROR_IS_SET (error);
990 dbus_message_unref (reply);
995 if (!dbus_message_get_args (reply, error,
996 DBUS_TYPE_STRING, &v_STRING,
999 _DBUS_ASSERT_ERROR_IS_SET (error);
1000 dbus_message_unref (reply);
1004 id = _dbus_strdup (v_STRING); /* may be NULL */
1006 dbus_message_unref (reply);
1009 _DBUS_SET_OOM (error);
1011 /* FIXME it might be nice to cache the ID locally */
1017 * Asks the bus to assign the given name to this connection by invoking
1018 * the RequestName method on the bus. This method is fully documented
1019 * in the D-Bus specification. For quick reference, the flags and
1020 * result codes are discussed here, but the specification is the
1021 * canonical version of this information.
1023 * First you should know that for each bus name, the bus stores
1024 * a queue of connections that would like to own it. Only
1025 * one owns it at a time - called the primary owner. If the primary
1026 * owner releases the name or disconnects, then the next owner in the
1027 * queue atomically takes over.
1029 * So for example if you have an application org.freedesktop.TextEditor
1030 * and multiple instances of it can be run, you can have all of them
1031 * sitting in the queue. The first one to start up will receive messages
1032 * sent to org.freedesktop.TextEditor, but if that one exits another
1033 * will become the primary owner and receive messages.
1035 * The queue means you don't need to manually watch for the current owner to
1036 * disappear and then request the name again.
1038 * When requesting a name, you can specify several flags.
1040 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT and #DBUS_NAME_FLAG_DO_NOT_QUEUE
1041 * are properties stored by the bus for this connection with respect to
1042 * each requested bus name. These properties are stored even if the
1043 * connection is queued and does not become the primary owner.
1044 * You can update these flags by calling RequestName again (even if
1045 * you already own the name).
1047 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT means that another requestor of the
1048 * name can take it away from you by specifying #DBUS_NAME_FLAG_REPLACE_EXISTING.
1050 * #DBUS_NAME_FLAG_DO_NOT_QUEUE means that if you aren't the primary owner,
1051 * you don't want to be queued up - you only care about being the
1054 * Unlike the other two flags, #DBUS_NAME_FLAG_REPLACE_EXISTING is a property
1055 * of the individual RequestName call, i.e. the bus does not persistently
1056 * associate it with the connection-name pair. If a RequestName call includes
1057 * the #DBUS_NAME_FLAG_REPLACE_EXISTING flag, and the current primary
1058 * owner has #DBUS_NAME_FLAG_ALLOW_REPLACEMENT set, then the current primary
1059 * owner will be kicked off.
1061 * If no flags are given, an application will receive the requested
1062 * name only if the name is currently unowned; and it will NOT give
1063 * up the name if another application asks to take it over using
1064 * #DBUS_NAME_FLAG_REPLACE_EXISTING.
1066 * This function returns a result code. The possible result codes
1069 * #DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER means that the name had no
1070 * existing owner, and the caller is now the primary owner; or that
1071 * the name had an owner, and the caller specified
1072 * #DBUS_NAME_FLAG_REPLACE_EXISTING, and the current owner
1073 * specified #DBUS_NAME_FLAG_ALLOW_REPLACEMENT.
1075 * #DBUS_REQUEST_NAME_REPLY_IN_QUEUE happens only if the caller does NOT
1076 * specify #DBUS_NAME_FLAG_DO_NOT_QUEUE and either the current owner
1077 * did NOT specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT
1078 * specify #DBUS_NAME_FLAG_REPLACE_EXISTING. In this case the caller ends up
1079 * in a queue to own the name after the current owner gives it up.
1081 * #DBUS_REQUEST_NAME_REPLY_EXISTS happens if the name has an owner
1082 * already and the caller specifies #DBUS_NAME_FLAG_DO_NOT_QUEUE
1083 * and either the current owner has NOT specified
1084 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT specify
1085 * #DBUS_NAME_FLAG_REPLACE_EXISTING.
1087 * #DBUS_REQUEST_NAME_REPLY_ALREADY_OWNER happens if an application
1088 * requests a name it already owns. (Re-requesting a name is useful if
1089 * you want to change the #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or
1090 * #DBUS_NAME_FLAG_DO_NOT_QUEUE settings.)
1092 * When a service represents an application, say "text editor," then
1093 * it should specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT if it wants
1094 * the last editor started to be the user's editor vs. the first one
1095 * started. Then any editor that can be the user's editor should
1096 * specify #DBUS_NAME_FLAG_REPLACE_EXISTING to either take over
1097 * (last-started-wins) or be queued up (first-started-wins) according
1098 * to whether #DBUS_NAME_FLAG_ALLOW_REPLACEMENT was given.
1100 * Conventionally, single-instance applications often offer a command
1101 * line option called --replace which means to replace the current
1102 * instance. To implement this, always set
1103 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT when you request your
1104 * application's bus name. When you lose ownership of your bus name,
1105 * you need to exit. Look for the signal "NameLost" from
1106 * #DBUS_SERVICE_DBUS and #DBUS_INTERFACE_DBUS (the signal's first
1107 * argument is the bus name that was lost). If starting up without
1108 * --replace, do not specify #DBUS_NAME_FLAG_REPLACE_EXISTING, and
1109 * exit if you fail to become the bus name owner. If --replace is
1110 * given, ask to replace the old owner.
1112 * @param connection the connection
1113 * @param name the name to request
1114 * @param flags flags
1115 * @param error location to store the error
1116 * @returns a result code, -1 if error is set
1119 dbus_bus_request_name (DBusConnection *connection,
1124 DBusMessage *message, *reply;
1125 dbus_uint32_t result;
1127 _dbus_return_val_if_fail (connection != NULL, 0);
1128 _dbus_return_val_if_fail (name != NULL, 0);
1129 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0);
1130 _dbus_return_val_if_error_is_set (error, 0);
1132 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1134 DBUS_INTERFACE_DBUS,
1137 if (message == NULL)
1139 _DBUS_SET_OOM (error);
1143 if (!dbus_message_append_args (message,
1144 DBUS_TYPE_STRING, &name,
1145 DBUS_TYPE_UINT32, &flags,
1148 dbus_message_unref (message);
1149 _DBUS_SET_OOM (error);
1153 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
1156 dbus_message_unref (message);
1160 _DBUS_ASSERT_ERROR_IS_SET (error);
1164 if (dbus_set_error_from_message (error, reply))
1166 _DBUS_ASSERT_ERROR_IS_SET (error);
1167 dbus_message_unref (reply);
1171 if (!dbus_message_get_args (reply, error,
1172 DBUS_TYPE_UINT32, &result,
1175 _DBUS_ASSERT_ERROR_IS_SET (error);
1176 dbus_message_unref (reply);
1180 dbus_message_unref (reply);
1187 * Asks the bus to unassign the given name from this connection by
1188 * invoking the ReleaseName method on the bus. The "ReleaseName"
1189 * method is canonically documented in the D-Bus specification.
1191 * Possible results are: #DBUS_RELEASE_NAME_REPLY_RELEASED
1192 * which means you owned the name or were in the queue to own it,
1193 * and and now you don't own it and aren't in the queue.
1194 * #DBUS_RELEASE_NAME_REPLY_NOT_OWNER which means someone else
1195 * owns the name so you can't release it.
1196 * #DBUS_RELEASE_NAME_REPLY_NON_EXISTENT
1197 * which means nobody owned the name.
1199 * @param connection the connection
1200 * @param name the name to remove
1201 * @param error location to store the error
1202 * @returns a result code, -1 if error is set
1205 dbus_bus_release_name (DBusConnection *connection,
1209 DBusMessage *message, *reply;
1210 dbus_uint32_t result;
1212 _dbus_return_val_if_fail (connection != NULL, 0);
1213 _dbus_return_val_if_fail (name != NULL, 0);
1214 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0);
1215 _dbus_return_val_if_error_is_set (error, 0);
1217 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1219 DBUS_INTERFACE_DBUS,
1222 if (message == NULL)
1224 _DBUS_SET_OOM (error);
1228 if (!dbus_message_append_args (message,
1229 DBUS_TYPE_STRING, &name,
1232 dbus_message_unref (message);
1233 _DBUS_SET_OOM (error);
1237 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
1240 dbus_message_unref (message);
1244 _DBUS_ASSERT_ERROR_IS_SET (error);
1248 if (dbus_set_error_from_message (error, reply))
1250 _DBUS_ASSERT_ERROR_IS_SET (error);
1251 dbus_message_unref (reply);
1255 if (!dbus_message_get_args (reply, error,
1256 DBUS_TYPE_UINT32, &result,
1259 _DBUS_ASSERT_ERROR_IS_SET (error);
1260 dbus_message_unref (reply);
1264 dbus_message_unref (reply);
1270 * Asks the bus whether a certain name has an owner.
1272 * Using this can easily result in a race condition,
1273 * since an owner can appear or disappear after you
1276 * If you want to request a name, just request it;
1277 * if you want to avoid replacing a current owner,
1278 * don't specify #DBUS_NAME_FLAG_REPLACE_EXISTING and
1279 * you will get an error if there's already an owner.
1281 * @param connection the connection
1282 * @param name the name
1283 * @param error location to store any errors
1284 * @returns #TRUE if the name exists, #FALSE if not or on error
1287 dbus_bus_name_has_owner (DBusConnection *connection,
1291 DBusMessage *message, *reply;
1294 _dbus_return_val_if_fail (connection != NULL, FALSE);
1295 _dbus_return_val_if_fail (name != NULL, FALSE);
1296 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE);
1297 _dbus_return_val_if_error_is_set (error, FALSE);
1299 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1301 DBUS_INTERFACE_DBUS,
1303 if (message == NULL)
1305 _DBUS_SET_OOM (error);
1309 if (!dbus_message_append_args (message,
1310 DBUS_TYPE_STRING, &name,
1313 dbus_message_unref (message);
1314 _DBUS_SET_OOM (error);
1318 reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
1319 dbus_message_unref (message);
1323 _DBUS_ASSERT_ERROR_IS_SET (error);
1327 if (!dbus_message_get_args (reply, error,
1328 DBUS_TYPE_BOOLEAN, &exists,
1331 _DBUS_ASSERT_ERROR_IS_SET (error);
1332 dbus_message_unref (reply);
1336 dbus_message_unref (reply);
1341 * Starts a service that will request ownership of the given name.
1342 * The returned result will be one of be one of
1343 * #DBUS_START_REPLY_SUCCESS or #DBUS_START_REPLY_ALREADY_RUNNING if
1344 * successful. Pass #NULL if you don't care about the result.
1346 * The flags parameter is for future expansion, currently you should
1349 * It's often easier to avoid explicitly starting services, and
1350 * just send a method call to the service's bus name instead.
1351 * Method calls start a service to handle them by default
1352 * unless you call dbus_message_set_auto_start() to disable this
1355 * @param connection the connection
1356 * @param name the name we want the new service to request
1357 * @param flags the flags (should always be 0 for now)
1358 * @param result a place to store the result or #NULL
1359 * @param error location to store any errors
1360 * @returns #TRUE if the activation succeeded, #FALSE if not
1363 dbus_bus_start_service_by_name (DBusConnection *connection,
1365 dbus_uint32_t flags,
1366 dbus_uint32_t *result,
1372 _dbus_return_val_if_fail (connection != NULL, FALSE);
1373 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE);
1375 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1377 DBUS_INTERFACE_DBUS,
1378 "StartServiceByName");
1380 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &name,
1381 DBUS_TYPE_UINT32, &flags, DBUS_TYPE_INVALID))
1383 dbus_message_unref (msg);
1384 _DBUS_SET_OOM (error);
1388 reply = dbus_connection_send_with_reply_and_block (connection, msg,
1390 dbus_message_unref (msg);
1394 _DBUS_ASSERT_ERROR_IS_SET (error);
1398 if (dbus_set_error_from_message (error, reply))
1400 _DBUS_ASSERT_ERROR_IS_SET (error);
1401 dbus_message_unref (reply);
1405 if (result != NULL &&
1406 !dbus_message_get_args (reply, error, DBUS_TYPE_UINT32,
1407 result, DBUS_TYPE_INVALID))
1409 _DBUS_ASSERT_ERROR_IS_SET (error);
1410 dbus_message_unref (reply);
1414 dbus_message_unref (reply);
1419 send_no_return_values (DBusConnection *connection,
1425 /* Block to check success codepath */
1428 reply = dbus_connection_send_with_reply_and_block (connection, msg,
1432 _DBUS_ASSERT_ERROR_IS_SET (error);
1434 dbus_message_unref (reply);
1438 /* Silently-fail nonblocking codepath */
1439 dbus_message_set_no_reply (msg, TRUE);
1440 dbus_connection_send (connection, msg, NULL);
1445 * Adds a match rule to match messages going through the message bus.
1446 * The "rule" argument is the string form of a match rule.
1448 * If you pass #NULL for the error, this function will not
1449 * block; the match thus won't be added until you flush the
1450 * connection, and if there's an error adding the match
1451 * you won't find out about it. This is generally acceptable, since the
1452 * possible errors (including a lack of resources in the bus, the connection
1453 * having exceeded its quota of active match rules, or the match rule being
1454 * unparseable) are generally unrecoverable.
1456 * If you pass non-#NULL for the error this function will
1457 * block until it gets a reply. This may be useful when using match rule keys
1458 * introduced in recent versions of D-Bus, like 'arg0namespace', to allow the
1459 * application to fall back to less efficient match rules supported by older
1460 * versions of the daemon if the running version is not new enough; or when
1461 * using user-supplied rules rather than rules hard-coded at compile time.
1463 * Normal API conventions would have the function return
1464 * a boolean value indicating whether the error was set,
1465 * but that would require blocking always to determine
1468 * The AddMatch method is fully documented in the D-Bus
1469 * specification. For quick reference, the format of the
1470 * match rules is discussed here, but the specification
1471 * is the canonical version of this information.
1473 * Rules are specified as a string of comma separated
1474 * key/value pairs. An example is
1475 * "type='signal',sender='org.freedesktop.DBus',
1476 * interface='org.freedesktop.DBus',member='Foo',
1477 * path='/bar/foo',destination=':452345.34'"
1479 * Possible keys you can match on are type, sender,
1480 * interface, member, path, destination and numbered
1481 * keys to match message args (keys are 'arg0', 'arg1', etc.).
1482 * Omitting a key from the rule indicates
1483 * a wildcard match. For instance omitting
1484 * the member from a match rule but adding a sender would
1485 * let all messages from that sender through regardless of
1488 * Matches are inclusive not exclusive so as long as one
1489 * rule matches the message will get through. It is important
1490 * to note this because every time a message is received the
1491 * application will be paged into memory to process it. This
1492 * can cause performance problems such as draining batteries
1493 * on embedded platforms.
1495 * If you match message args ('arg0', 'arg1', and so forth)
1496 * only string arguments will match. That is, arg0='5' means
1497 * match the string "5" not the integer 5.
1499 * Currently there is no way to match against non-string arguments.
1501 * A specialised form of wildcard matching on arguments is
1502 * supported for path-like namespaces. If your argument match has
1503 * a 'path' suffix (eg: "arg0path='/some/path/'") then it is
1504 * considered a match if the argument exactly matches the given
1505 * string or if one of them ends in a '/' and is a prefix of the
1508 * Matching on interface is tricky because method call
1509 * messages only optionally specify the interface.
1510 * If a message omits the interface, then it will NOT match
1511 * if the rule specifies an interface name. This means match
1512 * rules on method calls should not usually give an interface.
1514 * However, signal messages are required to include the interface
1515 * so when matching signals usually you should specify the interface
1516 * in the match rule.
1518 * For security reasons, you can match arguments only up to
1519 * #DBUS_MAXIMUM_MATCH_RULE_ARG_NUMBER.
1521 * Match rules have a maximum length of #DBUS_MAXIMUM_MATCH_RULE_LENGTH
1524 * Both of these maximums are much higher than you're likely to need,
1525 * they only exist because the D-Bus bus daemon has fixed limits on
1526 * all resource usage.
1528 * @param connection connection to the message bus
1529 * @param rule textual form of match rule
1530 * @param error location to store any errors
1533 dbus_bus_add_match (DBusConnection *connection,
1539 _dbus_return_if_fail (rule != NULL);
1541 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1543 DBUS_INTERFACE_DBUS,
1548 _DBUS_SET_OOM (error);
1552 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &rule,
1555 dbus_message_unref (msg);
1556 _DBUS_SET_OOM (error);
1560 send_no_return_values (connection, msg, error);
1562 dbus_message_unref (msg);
1566 * Removes a previously-added match rule "by value" (the most
1567 * recently-added identical rule gets removed). The "rule" argument
1568 * is the string form of a match rule.
1570 * The bus compares match rules semantically, not textually, so
1571 * whitespace and ordering don't have to be identical to
1572 * the rule you passed to dbus_bus_add_match().
1574 * If you pass #NULL for the error, this function will not
1575 * block; otherwise it will. See detailed explanation in
1576 * docs for dbus_bus_add_match().
1578 * @param connection connection to the message bus
1579 * @param rule textual form of match rule
1580 * @param error location to store any errors
1583 dbus_bus_remove_match (DBusConnection *connection,
1589 _dbus_return_if_fail (rule != NULL);
1591 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1593 DBUS_INTERFACE_DBUS,
1596 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &rule,
1599 dbus_message_unref (msg);
1600 _DBUS_SET_OOM (error);
1604 send_no_return_values (connection, msg, error);
1606 dbus_message_unref (msg);