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.
6 * Copyright (C) 2013 Samsung Electronics
8 * Licensed under the Academic Free License version 2.1
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
28 #include "dbus-protocol.h"
29 #include "dbus-internals.h"
30 #include "dbus-message.h"
31 #include "dbus-marshal-validate.h"
32 #include "dbus-misc.h"
33 #include "dbus-threads-internal.h"
34 #include "dbus-connection-internal.h"
35 #include "dbus-string.h"
36 #include "dbus-transport-kdbus.h"
42 * @defgroup DBusBus Message bus APIs
44 * @brief Functions for communicating with the message bus
46 * dbus_bus_get() allows all modules and libraries in a given
47 * process to share the same connection to the bus daemon by storing
48 * the connection globally.
50 * All other functions in this module are just convenience functions;
51 * most of them invoke methods on the bus daemon, by sending method
52 * call messages to #DBUS_SERVICE_DBUS. These convenience functions
53 * often make blocking method calls. If you don't want to block,
54 * you can send the method call messages manually in the same way
55 * you would any other method call message.
57 * This module is the only one in libdbus that's specific to
58 * communicating with the message bus daemon. The rest of the API can
59 * also be used for connecting to another application directly.
61 * @todo right now the default address of the system bus is hardcoded,
62 * so if you change it in the global config file suddenly you have to
63 * set DBUS_SYSTEM_BUS_ADDRESS env variable. Might be nice if the
64 * client lib somehow read the config file, or if the bus on startup
65 * somehow wrote out its address to a well-known spot, but might also
70 * @defgroup DBusBusInternals Message bus APIs internals
71 * @ingroup DBusInternals
72 * @brief Internals of functions for communicating with the message bus
78 * Block of message-bus-related data we attach to each
79 * #DBusConnection used with these convenience functions.
84 DBusConnection *connection; /**< Connection we're associated with */
85 char *unique_name; /**< Unique name of this connection */
87 unsigned int is_well_known : 1; /**< Is one of the well-known connections in our global array */
90 /** The slot we have reserved to store BusData.
92 static dbus_int32_t bus_data_slot = -1;
94 /** Number of bus types */
97 static DBusConnection *bus_connections[N_BUS_TYPES];
98 static char *bus_connection_addresses[N_BUS_TYPES] = { NULL, NULL, NULL };
100 static DBusBusType activation_bus_type = DBUS_BUS_STARTER;
102 static dbus_bool_t initialized = FALSE;
105 addresses_shutdown_func (void *data)
110 while (i < N_BUS_TYPES)
112 if (bus_connections[i] != NULL)
113 _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.\n");
115 dbus_free (bus_connection_addresses[i]);
116 bus_connection_addresses[i] = NULL;
120 activation_bus_type = DBUS_BUS_STARTER;
126 get_from_env (char **connection_p,
131 _dbus_assert (*connection_p == NULL);
133 s = _dbus_getenv (env_var);
134 if (s == NULL || *s == '\0')
135 return TRUE; /* successfully didn't use the env var */
138 *connection_p = _dbus_strdup (s);
139 return *connection_p != NULL;
143 void dbus_bus_set_bus_connection_address(DBusBusType address_type, char* address)
145 if(bus_connection_addresses[address_type] != NULL)
146 free(bus_connection_addresses[address_type]);
147 bus_connection_addresses[address_type] = address;
151 init_session_address (void)
157 /* First, look in the environment. This is the normal case on
158 * freedesktop.org/Unix systems. */
159 get_from_env (&bus_connection_addresses[DBUS_BUS_SESSION],
160 "DBUS_SESSION_BUS_ADDRESS");
161 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
163 dbus_bool_t supported;
165 DBusError error = DBUS_ERROR_INIT;
167 if (!_dbus_string_init (&addr))
171 /* So it's not in the environment - let's try a platform-specific method.
172 * On MacOS, this involves asking launchd. On Windows (not specified yet)
173 * we might do a COM lookup.
174 * Ignore errors - if we failed, fall back to autolaunch. */
175 retval = _dbus_lookup_session_address (&supported, &addr, &error);
176 if (supported && retval)
178 retval =_dbus_string_steal_data (&addr, &bus_connection_addresses[DBUS_BUS_SESSION]);
180 else if (supported && !retval)
182 if (dbus_error_is_set(&error))
183 _dbus_warn ("Dynamic session lookup supported but failed: %s\n", error.message);
185 _dbus_warn ("Dynamic session lookup supported but failed silently\n");
187 _dbus_string_free (&addr);
195 /* We have a hard-coded (but compile-time-configurable) fallback address for
196 * the session bus. */
197 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
198 bus_connection_addresses[DBUS_BUS_SESSION] =
199 _dbus_strdup (DBUS_SESSION_BUS_CONNECT_ADDRESS);
201 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
208 init_connections_unlocked (void)
216 while (i < N_BUS_TYPES)
218 bus_connections[i] = NULL;
222 /* Don't init these twice, we may run this code twice if
223 * init_connections_unlocked() fails midway through.
224 * In practice, each block below should contain only one
225 * "return FALSE" or running through twice may not
229 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
231 _dbus_verbose ("Filling in system bus address...\n");
233 if (!get_from_env (&bus_connection_addresses[DBUS_BUS_SYSTEM],
234 "DBUS_SYSTEM_BUS_ADDRESS"))
239 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
241 /* Use default system bus address if none set in environment */
242 bus_connection_addresses[DBUS_BUS_SYSTEM] =
243 _dbus_strdup (DBUS_SYSTEM_BUS_DEFAULT_ADDRESS);
245 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
248 _dbus_verbose (" used default system bus \"%s\"\n",
249 bus_connection_addresses[DBUS_BUS_SYSTEM]);
252 _dbus_verbose (" used env var system bus \"%s\"\n",
253 bus_connection_addresses[DBUS_BUS_SYSTEM]);
255 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
257 _dbus_verbose ("Filling in session bus address...\n");
259 if (!init_session_address ())
262 _dbus_verbose (" \"%s\"\n", bus_connection_addresses[DBUS_BUS_SESSION] ?
263 bus_connection_addresses[DBUS_BUS_SESSION] : "none set");
266 if (bus_connection_addresses[DBUS_BUS_STARTER] == NULL)
268 _dbus_verbose ("Filling in activation bus address...\n");
270 if (!get_from_env (&bus_connection_addresses[DBUS_BUS_STARTER],
271 "DBUS_STARTER_ADDRESS"))
274 _dbus_verbose (" \"%s\"\n", bus_connection_addresses[DBUS_BUS_STARTER] ?
275 bus_connection_addresses[DBUS_BUS_STARTER] : "none set");
279 if (bus_connection_addresses[DBUS_BUS_STARTER] != NULL)
281 s = _dbus_getenv ("DBUS_STARTER_BUS_TYPE");
285 _dbus_verbose ("Bus activation type was set to \"%s\"\n", s);
287 if (strcmp (s, "system") == 0)
288 activation_bus_type = DBUS_BUS_SYSTEM;
289 else if (strcmp (s, "session") == 0)
290 activation_bus_type = DBUS_BUS_SESSION;
295 /* Default to the session bus instead if available */
296 if (bus_connection_addresses[DBUS_BUS_SESSION] != NULL)
298 bus_connection_addresses[DBUS_BUS_STARTER] =
299 _dbus_strdup (bus_connection_addresses[DBUS_BUS_SESSION]);
300 if (bus_connection_addresses[DBUS_BUS_STARTER] == NULL)
305 /* If we return FALSE we have to be sure that restarting
306 * the above code will work right
309 if (!dbus_setenv ("DBUS_ACTIVATION_ADDRESS", NULL))
312 if (!dbus_setenv ("DBUS_ACTIVATION_BUS_TYPE", NULL))
315 if (!_dbus_register_shutdown_func (addresses_shutdown_func,
326 bus_data_free (void *data)
330 if (bd->is_well_known)
334 if (!_DBUS_LOCK (bus))
335 _dbus_assert_not_reached ("global locks should have been initialized "
336 "when we attached bus data");
338 /* We may be stored in more than one slot */
339 /* This should now be impossible - these slots are supposed to
340 * be cleared on disconnect, so should not need to be cleared on
344 while (i < N_BUS_TYPES)
346 if (bus_connections[i] == bd->connection)
347 bus_connections[i] = NULL;
354 dbus_free (bd->unique_name);
357 dbus_connection_free_data_slot (&bus_data_slot);
361 ensure_bus_data (DBusConnection *connection)
365 if (!dbus_connection_allocate_data_slot (&bus_data_slot))
368 bd = dbus_connection_get_data (connection, bus_data_slot);
371 bd = dbus_new0 (BusData, 1);
374 dbus_connection_free_data_slot (&bus_data_slot);
378 bd->connection = connection;
380 if (!dbus_connection_set_data (connection, bus_data_slot, bd,
384 dbus_connection_free_data_slot (&bus_data_slot);
388 /* Data slot refcount now held by the BusData */
392 dbus_connection_free_data_slot (&bus_data_slot);
399 * Internal function that checks to see if this
400 * is a shared connection owned by the bus and if it is unref it.
402 * @param connection a connection that has been disconnected.
405 _dbus_bus_notify_shared_connection_disconnected_unlocked (DBusConnection *connection)
409 if (!_DBUS_LOCK (bus))
411 /* If it was in bus_connections, we would have initialized global locks
412 * when we added it. So, it can't be. */
416 /* We are expecting to have the connection saved in only one of these
417 * slots, but someone could in a pathological case set system and session
418 * bus to the same bus or something. Or set one of them to the starter
419 * bus without setting the starter bus type in the env variable.
420 * So we don't break the loop as soon as we find a match.
422 for (i = 0; i < N_BUS_TYPES; ++i)
424 if (bus_connections[i] == connection)
426 bus_connections[i] = NULL;
433 static DBusConnection *
434 internal_bus_get (DBusBusType type,
439 DBusConnection *connection;
441 DBusBusType address_type;
443 _dbus_return_val_if_fail (type >= 0 && type < N_BUS_TYPES, NULL);
444 _dbus_return_val_if_error_is_set (error, NULL);
448 if (!_DBUS_LOCK (bus))
450 _DBUS_SET_OOM (error);
451 /* do not "goto out", that would try to unlock */
455 if (!init_connections_unlocked ())
457 _DBUS_SET_OOM (error);
461 /* We want to use the activation address even if the
462 * activating bus is the session or system bus,
467 /* Use the real type of the activation bus for getting its
468 * connection, but only if the real type's address is available. (If
469 * the activating bus isn't a well-known bus then
470 * activation_bus_type == DBUS_BUS_STARTER)
472 if (type == DBUS_BUS_STARTER &&
473 bus_connection_addresses[activation_bus_type] != NULL)
474 type = activation_bus_type;
476 if (!private && bus_connections[type] != NULL)
478 connection = bus_connections[type];
479 dbus_connection_ref (connection);
483 address = bus_connection_addresses[address_type];
486 dbus_set_error (error, DBUS_ERROR_FAILED,
487 "Unable to determine the address of the message bus (try 'man dbus-launch' and 'man dbus-daemon' for help)");
492 connection = dbus_connection_open_private (address, error);
494 connection = dbus_connection_open (address, error);
501 if (!dbus_bus_register (connection, error))
503 _dbus_connection_close_possibly_shared (connection);
504 dbus_connection_unref (connection);
511 /* store a weak ref to the connection (dbus-connection.c is
512 * supposed to have a strong ref that it drops on disconnect,
513 * since this is a shared connection)
515 bus_connections[type] = connection;
518 /* By default we're bound to the lifecycle of
521 dbus_connection_set_exit_on_disconnect (connection,
524 if (!_DBUS_LOCK (bus_datas))
525 _dbus_assert_not_reached ("global locks were initialized already");
527 bd = ensure_bus_data (connection);
528 _dbus_assert (bd != NULL); /* it should have been created on
529 register, so OOM not possible */
530 bd->is_well_known = TRUE;
531 _DBUS_UNLOCK (bus_datas);
534 /* Return a reference to the caller, or NULL with error set. */
535 if (connection == NULL)
536 _DBUS_ASSERT_ERROR_IS_SET (error);
543 /** @} */ /* end of implementation details docs */
546 * @addtogroup DBusBus
551 * Connects to a bus daemon and registers the client with it. If a
552 * connection to the bus already exists, then that connection is
553 * returned. The caller of this function owns a reference to the bus.
555 * The caller may NOT call dbus_connection_close() on this connection;
556 * see dbus_connection_open() and dbus_connection_close() for details
559 * If this function obtains a new connection object never before
560 * returned from dbus_bus_get(), it will call
561 * dbus_connection_set_exit_on_disconnect(), so the application
562 * will exit if the connection closes. You can undo this
563 * by calling dbus_connection_set_exit_on_disconnect() yourself
564 * after you get the connection.
566 * dbus_bus_get() calls dbus_bus_register() for you.
568 * If returning a newly-created connection, this function will block
569 * until authentication and bus registration are complete.
571 * @param type bus type
572 * @param error address where an error can be returned.
573 * @returns a #DBusConnection with new ref or #NULL on error
576 dbus_bus_get (DBusBusType type,
579 return internal_bus_get (type, FALSE, error);
583 * Connects to a bus daemon and registers the client with it as with
584 * dbus_bus_register(). Unlike dbus_bus_get(), always creates a new
585 * connection. This connection will not be saved or recycled by
586 * libdbus. Caller owns a reference to the bus and must either close
587 * it or know it to be closed prior to releasing this reference.
589 * See dbus_connection_open_private() for more details on when to
590 * close and unref this connection.
592 * This function calls
593 * dbus_connection_set_exit_on_disconnect() on the new connection, so the application
594 * will exit if the connection closes. You can undo this
595 * by calling dbus_connection_set_exit_on_disconnect() yourself
596 * after you get the connection.
598 * dbus_bus_get_private() calls dbus_bus_register() for you.
600 * This function will block until authentication and bus registration
603 * @param type bus type
604 * @param error address where an error can be returned.
605 * @returns a DBusConnection with new ref
608 dbus_bus_get_private (DBusBusType type,
611 return internal_bus_get (type, TRUE, error);
615 * Registers a connection with the bus. This must be the first
616 * thing an application does when connecting to the message bus.
617 * If registration succeeds, the unique name will be set,
618 * and can be obtained using dbus_bus_get_unique_name().
620 * This function will block until registration is complete.
622 * If the connection has already registered with the bus
623 * (determined by checking whether dbus_bus_get_unique_name()
624 * returns a non-#NULL value), then this function does nothing.
626 * If you use dbus_bus_get() or dbus_bus_get_private() this
627 * function will be called for you.
629 * @note Just use dbus_bus_get() or dbus_bus_get_private() instead of
630 * dbus_bus_register() and save yourself some pain. Using
631 * dbus_bus_register() manually is only useful if you have your
632 * own custom message bus not found in #DBusBusType.
634 * If you open a bus connection with dbus_connection_open() or
635 * dbus_connection_open_private() you will have to dbus_bus_register()
636 * yourself, or make the appropriate registration method calls
637 * yourself. If you send the method calls yourself, call
638 * dbus_bus_set_unique_name() with the unique bus name you get from
641 * For shared connections (created with dbus_connection_open()) in a
642 * multithreaded application, you can't really make the registration
643 * calls yourself, because you don't know whether some other thread is
644 * also registering, and the bus will kick you off if you send two
645 * registration messages.
647 * If you use dbus_bus_register() however, there is a lock that
648 * keeps both apps from registering at the same time.
650 * The rule in a multithreaded app, then, is that dbus_bus_register()
651 * must be used to register, or you need to have your own locks that
652 * all threads in the app will respect.
654 * In a single-threaded application you can register by hand instead
655 * of using dbus_bus_register(), as long as you check
656 * dbus_bus_get_unique_name() to see if a unique name has already been
657 * stored by another thread before you send the registration messages.
659 * @param connection the connection
660 * @param error place to store errors
661 * @returns #TRUE on success
664 dbus_bus_register (DBusConnection *connection,
667 DBusMessage *message, *reply;
672 _dbus_return_val_if_fail (connection != NULL, FALSE);
673 _dbus_return_val_if_error_is_set (error, FALSE);
679 if (!_DBUS_LOCK (bus_datas))
681 _DBUS_SET_OOM (error);
682 /* do not "goto out", that would try to unlock */
686 bd = ensure_bus_data (connection);
689 _DBUS_SET_OOM (error);
693 if (bd->unique_name != NULL)
695 _dbus_verbose ("Ignoring attempt to register the same DBusConnection %s with the message bus a second time.\n",
701 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
707 _DBUS_SET_OOM (error);
711 reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
715 else if (dbus_set_error_from_message (error, reply))
717 else if (!dbus_message_get_args (reply, error,
718 DBUS_TYPE_STRING, &name,
722 bd->unique_name = _dbus_strdup (name);
724 if (bd->unique_name == NULL)
726 _DBUS_SET_OOM (error);
729 //_dbus_verbose("-- Our uniqe name is: %s\n", bd->unique_name);
733 _DBUS_UNLOCK (bus_datas);
736 dbus_message_unref (message);
741 dbus_message_unref (reply);
744 _DBUS_ASSERT_ERROR_IS_SET (error);
751 * Sets the unique name of the connection, as assigned by the message
752 * bus. Can only be used if you registered with the bus manually
753 * (i.e. if you did not call dbus_bus_register()). Can only be called
754 * once per connection. After the unique name is set, you can get it
755 * with dbus_bus_get_unique_name().
757 * The only reason to use this function is to re-implement the
758 * equivalent of dbus_bus_register() yourself. One (probably unusual)
759 * reason to do that might be to do the bus registration call
760 * asynchronously instead of synchronously.
762 * @note Just use dbus_bus_get() or dbus_bus_get_private(), or worst
763 * case dbus_bus_register(), instead of messing with this
764 * function. There's really no point creating pain for yourself by
765 * doing things manually.
767 * It's hard to use this function safely on shared connections
768 * (created by dbus_connection_open()) in a multithreaded application,
769 * because only one registration attempt can be sent to the bus. If
770 * two threads are both sending the registration message, there is no
771 * mechanism in libdbus itself to avoid sending it twice.
773 * Thus, you need a way to coordinate which thread sends the
774 * registration attempt; which also means you know which thread
775 * will call dbus_bus_set_unique_name(). If you don't know
776 * about all threads in the app (for example, if some libraries
777 * you're using might start libdbus-using threads), then you
778 * need to avoid using this function on shared connections.
780 * @param connection the connection
781 * @param unique_name the unique name
782 * @returns #FALSE if not enough memory
785 dbus_bus_set_unique_name (DBusConnection *connection,
786 const char *unique_name)
789 dbus_bool_t success = FALSE;
791 _dbus_return_val_if_fail (connection != NULL, FALSE);
792 _dbus_return_val_if_fail (unique_name != NULL, FALSE);
794 if (!_DBUS_LOCK (bus_datas))
796 /* do not "goto out", that would try to unlock */
800 bd = ensure_bus_data (connection);
804 _dbus_assert (bd->unique_name == NULL);
806 bd->unique_name = _dbus_strdup (unique_name);
807 success = bd->unique_name != NULL;
810 _DBUS_UNLOCK (bus_datas);
816 * Gets the unique name of the connection as assigned by the message
817 * bus. Only possible after the connection has been registered with
818 * the message bus. All connections returned by dbus_bus_get() or
819 * dbus_bus_get_private() have been successfully registered.
821 * The name remains valid until the connection is freed, and
822 * should not be freed by the caller.
824 * Other than dbus_bus_get(), there are two ways to set the unique
825 * name; one is dbus_bus_register(), the other is
826 * dbus_bus_set_unique_name(). You are responsible for calling
827 * dbus_bus_set_unique_name() if you register by hand instead of using
828 * dbus_bus_register().
830 * @param connection the connection
831 * @returns the unique name or #NULL on error
834 dbus_bus_get_unique_name (DBusConnection *connection)
837 const char *unique_name = NULL;
839 _dbus_return_val_if_fail (connection != NULL, NULL);
841 if (!_DBUS_LOCK (bus_datas))
843 /* We'd have initialized locks when we gave it its unique name, if it
844 * had one. Don't "goto out", that would try to unlock. */
848 bd = ensure_bus_data (connection);
852 unique_name = bd->unique_name;
855 _DBUS_UNLOCK (bus_datas);
861 * Asks the bus to return the UID the named connection authenticated
862 * as, if any. Only works on UNIX; only works for connections on the
863 * same machine as the bus. If you are not on the same machine as the
864 * bus, then calling this is probably a bad idea, since the UID will
865 * mean little to your application.
867 * For the system message bus you're guaranteed to be on the same
868 * machine since it only listens on a UNIX domain socket (at least,
869 * as shipped by default).
871 * This function only works for connections that authenticated as
872 * a UNIX user, right now that includes all bus connections, but
873 * it's very possible to have connections with no associated UID.
874 * So check for errors and do something sensible if they happen.
876 * This function will always return an error on Windows.
878 * @param connection the connection
879 * @param name a name owned by the connection
880 * @param error location to store the error
881 * @returns the unix user id, or ((unsigned)-1) if error is set
884 dbus_bus_get_unix_user (DBusConnection *connection,
888 DBusMessage *message, *reply;
891 _dbus_return_val_if_fail (connection != NULL, DBUS_UID_UNSET);
892 _dbus_return_val_if_fail (name != NULL, DBUS_UID_UNSET);
893 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), DBUS_UID_UNSET);
894 _dbus_return_val_if_error_is_set (error, DBUS_UID_UNSET);
896 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
899 "GetConnectionUnixUser");
903 _DBUS_SET_OOM (error);
904 return DBUS_UID_UNSET;
907 if (!dbus_message_append_args (message,
908 DBUS_TYPE_STRING, &name,
911 dbus_message_unref (message);
912 _DBUS_SET_OOM (error);
913 return DBUS_UID_UNSET;
916 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
919 dbus_message_unref (message);
923 _DBUS_ASSERT_ERROR_IS_SET (error);
924 return DBUS_UID_UNSET;
927 if (dbus_set_error_from_message (error, reply))
929 _DBUS_ASSERT_ERROR_IS_SET (error);
930 dbus_message_unref (reply);
931 return DBUS_UID_UNSET;
934 if (!dbus_message_get_args (reply, error,
935 DBUS_TYPE_UINT32, &uid,
938 _DBUS_ASSERT_ERROR_IS_SET (error);
939 dbus_message_unref (reply);
940 return DBUS_UID_UNSET;
943 dbus_message_unref (reply);
945 return (unsigned long) uid;
949 * Asks the bus to return its globally unique ID, as described in the
950 * D-Bus specification. For the session bus, this is useful as a way
951 * to uniquely identify each user session. For the system bus,
952 * probably the bus ID is not useful; instead, use the machine ID
953 * since it's accessible without necessarily connecting to the bus and
954 * may be persistent beyond a single bus instance (across reboots for
955 * example). See dbus_get_local_machine_id().
957 * In addition to an ID for each bus and an ID for each machine, there is
958 * an ID for each address that the bus is listening on; that can
959 * be retrieved with dbus_connection_get_server_id(), though it is
960 * probably not very useful.
962 * @param connection the connection
963 * @param error location to store the error
964 * @returns the bus ID or #NULL if error is set
967 dbus_bus_get_id (DBusConnection *connection,
970 DBusMessage *message, *reply;
972 const char *v_STRING;
974 _dbus_return_val_if_fail (connection != NULL, NULL);
975 _dbus_return_val_if_error_is_set (error, NULL);
977 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
984 _DBUS_SET_OOM (error);
988 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
991 dbus_message_unref (message);
995 _DBUS_ASSERT_ERROR_IS_SET (error);
999 if (dbus_set_error_from_message (error, reply))
1001 _DBUS_ASSERT_ERROR_IS_SET (error);
1002 dbus_message_unref (reply);
1007 if (!dbus_message_get_args (reply, error,
1008 DBUS_TYPE_STRING, &v_STRING,
1011 _DBUS_ASSERT_ERROR_IS_SET (error);
1012 dbus_message_unref (reply);
1016 id = _dbus_strdup (v_STRING); /* may be NULL */
1018 dbus_message_unref (reply);
1021 _DBUS_SET_OOM (error);
1023 /* FIXME it might be nice to cache the ID locally */
1029 * Asks the bus to assign the given name to this connection by invoking
1030 * the RequestName method on the bus. This method is fully documented
1031 * in the D-Bus specification. For quick reference, the flags and
1032 * result codes are discussed here, but the specification is the
1033 * canonical version of this information.
1035 * First you should know that for each bus name, the bus stores
1036 * a queue of connections that would like to own it. Only
1037 * one owns it at a time - called the primary owner. If the primary
1038 * owner releases the name or disconnects, then the next owner in the
1039 * queue atomically takes over.
1041 * So for example if you have an application org.freedesktop.TextEditor
1042 * and multiple instances of it can be run, you can have all of them
1043 * sitting in the queue. The first one to start up will receive messages
1044 * sent to org.freedesktop.TextEditor, but if that one exits another
1045 * will become the primary owner and receive messages.
1047 * The queue means you don't need to manually watch for the current owner to
1048 * disappear and then request the name again.
1050 * When requesting a name, you can specify several flags.
1052 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT and #DBUS_NAME_FLAG_DO_NOT_QUEUE
1053 * are properties stored by the bus for this connection with respect to
1054 * each requested bus name. These properties are stored even if the
1055 * connection is queued and does not become the primary owner.
1056 * You can update these flags by calling RequestName again (even if
1057 * you already own the name).
1059 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT means that another requestor of the
1060 * name can take it away from you by specifying #DBUS_NAME_FLAG_REPLACE_EXISTING.
1062 * #DBUS_NAME_FLAG_DO_NOT_QUEUE means that if you aren't the primary owner,
1063 * you don't want to be queued up - you only care about being the
1066 * Unlike the other two flags, #DBUS_NAME_FLAG_REPLACE_EXISTING is a property
1067 * of the individual RequestName call, i.e. the bus does not persistently
1068 * associate it with the connection-name pair. If a RequestName call includes
1069 * the #DBUS_NAME_FLAG_REPLACE_EXISTING flag, and the current primary
1070 * owner has #DBUS_NAME_FLAG_ALLOW_REPLACEMENT set, then the current primary
1071 * owner will be kicked off.
1073 * If no flags are given, an application will receive the requested
1074 * name only if the name is currently unowned; and it will NOT give
1075 * up the name if another application asks to take it over using
1076 * #DBUS_NAME_FLAG_REPLACE_EXISTING.
1078 * This function returns a result code. The possible result codes
1081 * #DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER means that the name had no
1082 * existing owner, and the caller is now the primary owner; or that
1083 * the name had an owner, and the caller specified
1084 * #DBUS_NAME_FLAG_REPLACE_EXISTING, and the current owner
1085 * specified #DBUS_NAME_FLAG_ALLOW_REPLACEMENT.
1087 * #DBUS_REQUEST_NAME_REPLY_IN_QUEUE happens only if the caller does NOT
1088 * specify #DBUS_NAME_FLAG_DO_NOT_QUEUE and either the current owner
1089 * did NOT specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT
1090 * specify #DBUS_NAME_FLAG_REPLACE_EXISTING. In this case the caller ends up
1091 * in a queue to own the name after the current owner gives it up.
1093 * #DBUS_REQUEST_NAME_REPLY_EXISTS happens if the name has an owner
1094 * already and the caller specifies #DBUS_NAME_FLAG_DO_NOT_QUEUE
1095 * and either the current owner has NOT specified
1096 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT specify
1097 * #DBUS_NAME_FLAG_REPLACE_EXISTING.
1099 * #DBUS_REQUEST_NAME_REPLY_ALREADY_OWNER happens if an application
1100 * requests a name it already owns. (Re-requesting a name is useful if
1101 * you want to change the #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or
1102 * #DBUS_NAME_FLAG_DO_NOT_QUEUE settings.)
1104 * When a service represents an application, say "text editor," then
1105 * it should specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT if it wants
1106 * the last editor started to be the user's editor vs. the first one
1107 * started. Then any editor that can be the user's editor should
1108 * specify #DBUS_NAME_FLAG_REPLACE_EXISTING to either take over
1109 * (last-started-wins) or be queued up (first-started-wins) according
1110 * to whether #DBUS_NAME_FLAG_ALLOW_REPLACEMENT was given.
1112 * Conventionally, single-instance applications often offer a command
1113 * line option called --replace which means to replace the current
1114 * instance. To implement this, always set
1115 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT when you request your
1116 * application's bus name. When you lose ownership of your bus name,
1117 * you need to exit. Look for the signal "NameLost" from
1118 * #DBUS_SERVICE_DBUS and #DBUS_INTERFACE_DBUS (the signal's first
1119 * argument is the bus name that was lost). If starting up without
1120 * --replace, do not specify #DBUS_NAME_FLAG_REPLACE_EXISTING, and
1121 * exit if you fail to become the bus name owner. If --replace is
1122 * given, ask to replace the old owner.
1124 * @param connection the connection
1125 * @param name the name to request
1126 * @param flags flags
1127 * @param error location to store the error
1128 * @returns a result code, -1 if error is set
1131 dbus_bus_request_name (DBusConnection *connection,
1136 dbus_uint32_t result;
1137 DBusMessage *message, *reply;
1139 _dbus_return_val_if_fail (connection != NULL, 0);
1140 _dbus_return_val_if_fail (name != NULL, 0);
1141 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0);
1142 _dbus_return_val_if_error_is_set (error, 0);
1144 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1146 DBUS_INTERFACE_DBUS,
1148 if (message == NULL)
1150 _DBUS_SET_OOM (error);
1154 if (!dbus_message_append_args (message,
1155 DBUS_TYPE_STRING, &name,
1156 DBUS_TYPE_UINT32, &flags,
1159 dbus_message_unref (message);
1160 _DBUS_SET_OOM (error);
1164 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
1167 dbus_message_unref (message);
1171 _DBUS_ASSERT_ERROR_IS_SET (error);
1175 if (dbus_set_error_from_message (error, reply))
1177 _DBUS_ASSERT_ERROR_IS_SET (error);
1178 dbus_message_unref (reply);
1182 if (!dbus_message_get_args (reply, error,
1183 DBUS_TYPE_UINT32, &result,
1186 _DBUS_ASSERT_ERROR_IS_SET (error);
1187 dbus_message_unref (reply);
1191 dbus_message_unref (reply);
1197 * Asks the bus to unassign the given name from this connection by
1198 * invoking the ReleaseName method on the bus. The "ReleaseName"
1199 * method is canonically documented in the D-Bus specification.
1201 * Possible results are: #DBUS_RELEASE_NAME_REPLY_RELEASED
1202 * which means you owned the name or were in the queue to own it,
1203 * and and now you don't own it and aren't in the queue.
1204 * #DBUS_RELEASE_NAME_REPLY_NOT_OWNER which means someone else
1205 * owns the name so you can't release it.
1206 * #DBUS_RELEASE_NAME_REPLY_NON_EXISTENT
1207 * which means nobody owned the name.
1209 * @param connection the connection
1210 * @param name the name to remove
1211 * @param error location to store the error
1212 * @returns a result code, -1 if error is set
1215 dbus_bus_release_name (DBusConnection *connection,
1219 DBusMessage *message, *reply;
1220 dbus_uint32_t result;
1222 _dbus_return_val_if_fail (connection != NULL, 0);
1223 _dbus_return_val_if_fail (name != NULL, 0);
1224 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0);
1225 _dbus_return_val_if_error_is_set (error, 0);
1227 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1229 DBUS_INTERFACE_DBUS,
1232 if (message == NULL)
1234 _DBUS_SET_OOM (error);
1238 if (!dbus_message_append_args (message,
1239 DBUS_TYPE_STRING, &name,
1242 dbus_message_unref (message);
1243 _DBUS_SET_OOM (error);
1247 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
1250 dbus_message_unref (message);
1254 _DBUS_ASSERT_ERROR_IS_SET (error);
1258 if (dbus_set_error_from_message (error, reply))
1260 _DBUS_ASSERT_ERROR_IS_SET (error);
1261 dbus_message_unref (reply);
1265 if (!dbus_message_get_args (reply, error,
1266 DBUS_TYPE_UINT32, &result,
1269 _DBUS_ASSERT_ERROR_IS_SET (error);
1270 dbus_message_unref (reply);
1274 dbus_message_unref (reply);
1280 * Asks the bus whether a certain name has an owner.
1282 * Using this can easily result in a race condition,
1283 * since an owner can appear or disappear after you
1286 * If you want to request a name, just request it;
1287 * if you want to avoid replacing a current owner,
1288 * don't specify #DBUS_NAME_FLAG_REPLACE_EXISTING and
1289 * you will get an error if there's already an owner.
1291 * @param connection the connection
1292 * @param name the name
1293 * @param error location to store any errors
1294 * @returns #TRUE if the name exists, #FALSE if not or on error
1297 dbus_bus_name_has_owner (DBusConnection *connection,
1301 DBusMessage *message, *reply;
1304 _dbus_return_val_if_fail (connection != NULL, FALSE);
1305 _dbus_return_val_if_fail (name != NULL, FALSE);
1306 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE);
1307 _dbus_return_val_if_error_is_set (error, FALSE);
1309 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1311 DBUS_INTERFACE_DBUS,
1313 if (message == NULL)
1315 _DBUS_SET_OOM (error);
1319 if (!dbus_message_append_args (message,
1320 DBUS_TYPE_STRING, &name,
1323 dbus_message_unref (message);
1324 _DBUS_SET_OOM (error);
1328 reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
1329 dbus_message_unref (message);
1333 _DBUS_ASSERT_ERROR_IS_SET (error);
1337 if (!dbus_message_get_args (reply, error,
1338 DBUS_TYPE_BOOLEAN, &exists,
1341 _DBUS_ASSERT_ERROR_IS_SET (error);
1342 dbus_message_unref (reply);
1346 dbus_message_unref (reply);
1351 * Starts a service that will request ownership of the given name.
1352 * The returned result will be one of be one of
1353 * #DBUS_START_REPLY_SUCCESS or #DBUS_START_REPLY_ALREADY_RUNNING if
1354 * successful. Pass #NULL if you don't care about the result.
1356 * The flags parameter is for future expansion, currently you should
1359 * It's often easier to avoid explicitly starting services, and
1360 * just send a method call to the service's bus name instead.
1361 * Method calls start a service to handle them by default
1362 * unless you call dbus_message_set_auto_start() to disable this
1365 * @param connection the connection
1366 * @param name the name we want the new service to request
1367 * @param flags the flags (should always be 0 for now)
1368 * @param result a place to store the result or #NULL
1369 * @param error location to store any errors
1370 * @returns #TRUE if the activation succeeded, #FALSE if not
1373 dbus_bus_start_service_by_name (DBusConnection *connection,
1375 dbus_uint32_t flags,
1376 dbus_uint32_t *result,
1382 _dbus_return_val_if_fail (connection != NULL, FALSE);
1383 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE);
1385 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1387 DBUS_INTERFACE_DBUS,
1388 "StartServiceByName");
1390 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &name,
1391 DBUS_TYPE_UINT32, &flags, DBUS_TYPE_INVALID))
1393 dbus_message_unref (msg);
1394 _DBUS_SET_OOM (error);
1398 reply = dbus_connection_send_with_reply_and_block (connection, msg,
1400 dbus_message_unref (msg);
1404 _DBUS_ASSERT_ERROR_IS_SET (error);
1408 if (dbus_set_error_from_message (error, reply))
1410 _DBUS_ASSERT_ERROR_IS_SET (error);
1411 dbus_message_unref (reply);
1415 if (result != NULL &&
1416 !dbus_message_get_args (reply, error, DBUS_TYPE_UINT32,
1417 result, DBUS_TYPE_INVALID))
1419 _DBUS_ASSERT_ERROR_IS_SET (error);
1420 dbus_message_unref (reply);
1424 dbus_message_unref (reply);
1429 send_no_return_values (DBusConnection *connection,
1435 /* Block to check success codepath */
1438 reply = dbus_connection_send_with_reply_and_block (connection, msg,
1442 _DBUS_ASSERT_ERROR_IS_SET (error);
1444 dbus_message_unref (reply);
1448 /* Silently-fail nonblocking codepath */
1449 dbus_message_set_no_reply (msg, TRUE);
1450 dbus_connection_send (connection, msg, NULL);
1455 * Adds a match rule to match messages going through the message bus.
1456 * The "rule" argument is the string form of a match rule.
1458 * If you pass #NULL for the error, this function will not
1459 * block; the match thus won't be added until you flush the
1460 * connection, and if there's an error adding the match
1461 * you won't find out about it. This is generally acceptable, since the
1462 * possible errors (including a lack of resources in the bus, the connection
1463 * having exceeded its quota of active match rules, or the match rule being
1464 * unparseable) are generally unrecoverable.
1466 * If you pass non-#NULL for the error this function will
1467 * block until it gets a reply. This may be useful when using match rule keys
1468 * introduced in recent versions of D-Bus, like 'arg0namespace', to allow the
1469 * application to fall back to less efficient match rules supported by older
1470 * versions of the daemon if the running version is not new enough; or when
1471 * using user-supplied rules rather than rules hard-coded at compile time.
1473 * Normal API conventions would have the function return
1474 * a boolean value indicating whether the error was set,
1475 * but that would require blocking always to determine
1478 * The AddMatch method is fully documented in the D-Bus
1479 * specification. For quick reference, the format of the
1480 * match rules is discussed here, but the specification
1481 * is the canonical version of this information.
1483 * Rules are specified as a string of comma separated
1484 * key/value pairs. An example is
1485 * "type='signal',sender='org.freedesktop.DBus',
1486 * interface='org.freedesktop.DBus',member='Foo',
1487 * path='/bar/foo',destination=':452345.34'"
1489 * Possible keys you can match on are type, sender,
1490 * interface, member, path, destination and numbered
1491 * keys to match message args (keys are 'arg0', 'arg1', etc.).
1492 * Omitting a key from the rule indicates
1493 * a wildcard match. For instance omitting
1494 * the member from a match rule but adding a sender would
1495 * let all messages from that sender through regardless of
1498 * Matches are inclusive not exclusive so as long as one
1499 * rule matches the message will get through. It is important
1500 * to note this because every time a message is received the
1501 * application will be paged into memory to process it. This
1502 * can cause performance problems such as draining batteries
1503 * on embedded platforms.
1505 * If you match message args ('arg0', 'arg1', and so forth)
1506 * only string arguments will match. That is, arg0='5' means
1507 * match the string "5" not the integer 5.
1509 * Currently there is no way to match against non-string arguments.
1511 * A specialised form of wildcard matching on arguments is
1512 * supported for path-like namespaces. If your argument match has
1513 * a 'path' suffix (eg: "arg0path='/some/path/'") then it is
1514 * considered a match if the argument exactly matches the given
1515 * string or if one of them ends in a '/' and is a prefix of the
1518 * Matching on interface is tricky because method call
1519 * messages only optionally specify the interface.
1520 * If a message omits the interface, then it will NOT match
1521 * if the rule specifies an interface name. This means match
1522 * rules on method calls should not usually give an interface.
1524 * However, signal messages are required to include the interface
1525 * so when matching signals usually you should specify the interface
1526 * in the match rule.
1528 * For security reasons, you can match arguments only up to
1529 * #DBUS_MAXIMUM_MATCH_RULE_ARG_NUMBER.
1531 * Match rules have a maximum length of #DBUS_MAXIMUM_MATCH_RULE_LENGTH
1534 * Both of these maximums are much higher than you're likely to need,
1535 * they only exist because the D-Bus bus daemon has fixed limits on
1536 * all resource usage.
1538 * @param connection connection to the message bus
1539 * @param rule textual form of match rule
1540 * @param error location to store any errors
1543 dbus_bus_add_match (DBusConnection *connection,
1549 _dbus_return_if_fail (rule != NULL);
1551 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1553 DBUS_INTERFACE_DBUS,
1558 _DBUS_SET_OOM (error);
1562 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &rule,
1565 dbus_message_unref (msg);
1566 _DBUS_SET_OOM (error);
1570 send_no_return_values (connection, msg, error);
1572 dbus_message_unref (msg);
1576 * Removes a previously-added match rule "by value" (the most
1577 * recently-added identical rule gets removed). The "rule" argument
1578 * is the string form of a match rule.
1580 * The bus compares match rules semantically, not textually, so
1581 * whitespace and ordering don't have to be identical to
1582 * the rule you passed to dbus_bus_add_match().
1584 * If you pass #NULL for the error, this function will not
1585 * block; otherwise it will. See detailed explanation in
1586 * docs for dbus_bus_add_match().
1588 * @param connection connection to the message bus
1589 * @param rule textual form of match rule
1590 * @param error location to store any errors
1593 dbus_bus_remove_match (DBusConnection *connection,
1599 _dbus_return_if_fail (rule != NULL);
1601 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1603 DBUS_INTERFACE_DBUS,
1606 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &rule,
1609 dbus_message_unref (msg);
1610 _DBUS_SET_OOM (error);
1614 send_no_return_values (connection, msg, error);
1616 dbus_message_unref (msg);