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"
35 #include "dbus-transport-kdbus.h"
41 * @defgroup DBusBus Message bus APIs
43 * @brief Functions for communicating with the message bus
45 * dbus_bus_get() allows all modules and libraries in a given
46 * process to share the same connection to the bus daemon by storing
47 * the connection globally.
49 * All other functions in this module are just convenience functions;
50 * most of them invoke methods on the bus daemon, by sending method
51 * call messages to #DBUS_SERVICE_DBUS. These convenience functions
52 * often make blocking method calls. If you don't want to block,
53 * you can send the method call messages manually in the same way
54 * you would any other method call message.
56 * This module is the only one in libdbus that's specific to
57 * communicating with the message bus daemon. The rest of the API can
58 * also be used for connecting to another application directly.
60 * @todo right now the default address of the system bus is hardcoded,
61 * so if you change it in the global config file suddenly you have to
62 * set DBUS_SYSTEM_BUS_ADDRESS env variable. Might be nice if the
63 * client lib somehow read the config file, or if the bus on startup
64 * somehow wrote out its address to a well-known spot, but might also
69 * @defgroup DBusBusInternals Message bus APIs internals
70 * @ingroup DBusInternals
71 * @brief Internals of functions for communicating with the message bus
77 * Block of message-bus-related data we attach to each
78 * #DBusConnection used with these convenience functions.
83 DBusConnection *connection; /**< Connection we're associated with */
84 char *unique_name; /**< Unique name of this connection */
86 unsigned int is_well_known : 1; /**< Is one of the well-known connections in our global array */
89 /** The slot we have reserved to store BusData.
91 static dbus_int32_t bus_data_slot = -1;
93 /** Number of bus types */
96 static DBusConnection *bus_connections[N_BUS_TYPES];
97 static char *bus_connection_addresses[N_BUS_TYPES] = { NULL, NULL, NULL };
99 static DBusBusType activation_bus_type = DBUS_BUS_STARTER;
101 static dbus_bool_t initialized = FALSE;
104 addresses_shutdown_func (void *data)
109 while (i < N_BUS_TYPES)
111 if (bus_connections[i] != NULL)
112 _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");
114 dbus_free (bus_connection_addresses[i]);
115 bus_connection_addresses[i] = NULL;
119 activation_bus_type = DBUS_BUS_STARTER;
125 get_from_env (char **connection_p,
130 _dbus_assert (*connection_p == NULL);
132 s = _dbus_getenv (env_var);
133 if (s == NULL || *s == '\0')
134 return TRUE; /* successfully didn't use the env var */
137 *connection_p = _dbus_strdup (s);
138 return *connection_p != NULL;
142 void dbus_bus_set_bus_connection_address(DBusBusType address_type, char* address)
144 if(bus_connection_addresses[address_type] != NULL)
145 free(bus_connection_addresses[address_type]);
146 bus_connection_addresses[address_type] = address;
150 init_session_address (void)
156 /* First, look in the environment. This is the normal case on
157 * freedesktop.org/Unix systems. */
158 get_from_env (&bus_connection_addresses[DBUS_BUS_SESSION],
159 "DBUS_SESSION_BUS_ADDRESS");
160 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
162 dbus_bool_t supported;
164 DBusError error = DBUS_ERROR_INIT;
166 if (!_dbus_string_init (&addr))
170 /* So it's not in the environment - let's try a platform-specific method.
171 * On MacOS, this involves asking launchd. On Windows (not specified yet)
172 * we might do a COM lookup.
173 * Ignore errors - if we failed, fall back to autolaunch. */
174 retval = _dbus_lookup_session_address (&supported, &addr, &error);
175 if (supported && retval)
177 retval =_dbus_string_steal_data (&addr, &bus_connection_addresses[DBUS_BUS_SESSION]);
179 else if (supported && !retval)
181 if (dbus_error_is_set(&error))
182 _dbus_warn ("Dynamic session lookup supported but failed: %s\n", error.message);
184 _dbus_warn ("Dynamic session lookup supported but failed silently\n");
186 _dbus_string_free (&addr);
194 /* We have a hard-coded (but compile-time-configurable) fallback address for
195 * the session bus. */
196 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
197 bus_connection_addresses[DBUS_BUS_SESSION] =
198 _dbus_strdup (DBUS_SESSION_BUS_CONNECT_ADDRESS);
200 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
207 init_connections_unlocked (void)
215 while (i < N_BUS_TYPES)
217 bus_connections[i] = NULL;
221 /* Don't init these twice, we may run this code twice if
222 * init_connections_unlocked() fails midway through.
223 * In practice, each block below should contain only one
224 * "return FALSE" or running through twice may not
228 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
230 _dbus_verbose ("Filling in system bus address...\n");
232 if (!get_from_env (&bus_connection_addresses[DBUS_BUS_SYSTEM],
233 "DBUS_SYSTEM_BUS_ADDRESS"))
238 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
240 /* Use default system bus address if none set in environment */
241 bus_connection_addresses[DBUS_BUS_SYSTEM] =
242 _dbus_strdup (DBUS_SYSTEM_BUS_DEFAULT_ADDRESS);
244 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
247 _dbus_verbose (" used default system bus \"%s\"\n",
248 bus_connection_addresses[DBUS_BUS_SYSTEM]);
251 _dbus_verbose (" used env var system bus \"%s\"\n",
252 bus_connection_addresses[DBUS_BUS_SYSTEM]);
254 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
256 _dbus_verbose ("Filling in session bus address...\n");
258 if (!init_session_address ())
261 _dbus_verbose (" \"%s\"\n", bus_connection_addresses[DBUS_BUS_SESSION] ?
262 bus_connection_addresses[DBUS_BUS_SESSION] : "none set");
265 if (bus_connection_addresses[DBUS_BUS_STARTER] == NULL)
267 _dbus_verbose ("Filling in activation bus address...\n");
269 if (!get_from_env (&bus_connection_addresses[DBUS_BUS_STARTER],
270 "DBUS_STARTER_ADDRESS"))
273 _dbus_verbose (" \"%s\"\n", bus_connection_addresses[DBUS_BUS_STARTER] ?
274 bus_connection_addresses[DBUS_BUS_STARTER] : "none set");
278 if (bus_connection_addresses[DBUS_BUS_STARTER] != NULL)
280 s = _dbus_getenv ("DBUS_STARTER_BUS_TYPE");
284 _dbus_verbose ("Bus activation type was set to \"%s\"\n", s);
286 if (strcmp (s, "system") == 0)
287 activation_bus_type = DBUS_BUS_SYSTEM;
288 else if (strcmp (s, "session") == 0)
289 activation_bus_type = DBUS_BUS_SESSION;
294 /* Default to the session bus instead if available */
295 if (bus_connection_addresses[DBUS_BUS_SESSION] != NULL)
297 bus_connection_addresses[DBUS_BUS_STARTER] =
298 _dbus_strdup (bus_connection_addresses[DBUS_BUS_SESSION]);
299 if (bus_connection_addresses[DBUS_BUS_STARTER] == NULL)
304 /* If we return FALSE we have to be sure that restarting
305 * the above code will work right
308 if (!dbus_setenv ("DBUS_ACTIVATION_ADDRESS", NULL))
311 if (!dbus_setenv ("DBUS_ACTIVATION_BUS_TYPE", NULL))
314 if (!_dbus_register_shutdown_func (addresses_shutdown_func,
325 bus_data_free (void *data)
329 if (bd->is_well_known)
333 if (!_DBUS_LOCK (bus))
334 _dbus_assert_not_reached ("global locks should have been initialized "
335 "when we attached bus data");
337 /* We may be stored in more than one slot */
338 /* This should now be impossible - these slots are supposed to
339 * be cleared on disconnect, so should not need to be cleared on
343 while (i < N_BUS_TYPES)
345 if (bus_connections[i] == bd->connection)
346 bus_connections[i] = NULL;
353 dbus_free (bd->unique_name);
356 dbus_connection_free_data_slot (&bus_data_slot);
360 ensure_bus_data (DBusConnection *connection)
364 if (!dbus_connection_allocate_data_slot (&bus_data_slot))
367 bd = dbus_connection_get_data (connection, bus_data_slot);
370 bd = dbus_new0 (BusData, 1);
373 dbus_connection_free_data_slot (&bus_data_slot);
377 bd->connection = connection;
379 if (!dbus_connection_set_data (connection, bus_data_slot, bd,
383 dbus_connection_free_data_slot (&bus_data_slot);
387 /* Data slot refcount now held by the BusData */
391 dbus_connection_free_data_slot (&bus_data_slot);
398 * Internal function that checks to see if this
399 * is a shared connection owned by the bus and if it is unref it.
401 * @param connection a connection that has been disconnected.
404 _dbus_bus_notify_shared_connection_disconnected_unlocked (DBusConnection *connection)
408 if (!_DBUS_LOCK (bus))
410 /* If it was in bus_connections, we would have initialized global locks
411 * when we added it. So, it can't be. */
415 /* We are expecting to have the connection saved in only one of these
416 * slots, but someone could in a pathological case set system and session
417 * bus to the same bus or something. Or set one of them to the starter
418 * bus without setting the starter bus type in the env variable.
419 * So we don't break the loop as soon as we find a match.
421 for (i = 0; i < N_BUS_TYPES; ++i)
423 if (bus_connections[i] == connection)
425 bus_connections[i] = NULL;
432 static DBusConnection *
433 internal_bus_get (DBusBusType type,
438 DBusConnection *connection;
440 DBusBusType address_type;
442 _dbus_return_val_if_fail (type >= 0 && type < N_BUS_TYPES, NULL);
443 _dbus_return_val_if_error_is_set (error, NULL);
447 if (!_DBUS_LOCK (bus))
449 _DBUS_SET_OOM (error);
450 /* do not "goto out", that would try to unlock */
454 if (!init_connections_unlocked ())
456 _DBUS_SET_OOM (error);
460 /* We want to use the activation address even if the
461 * activating bus is the session or system bus,
466 /* Use the real type of the activation bus for getting its
467 * connection, but only if the real type's address is available. (If
468 * the activating bus isn't a well-known bus then
469 * activation_bus_type == DBUS_BUS_STARTER)
471 if (type == DBUS_BUS_STARTER &&
472 bus_connection_addresses[activation_bus_type] != NULL)
473 type = activation_bus_type;
475 if (!private && bus_connections[type] != NULL)
477 connection = bus_connections[type];
478 dbus_connection_ref (connection);
482 address = bus_connection_addresses[address_type];
485 dbus_set_error (error, DBUS_ERROR_FAILED,
486 "Unable to determine the address of the message bus (try 'man dbus-launch' and 'man dbus-daemon' for help)");
491 connection = dbus_connection_open_private (address, error);
493 connection = dbus_connection_open (address, error);
500 if (!dbus_bus_register (connection, error))
502 _dbus_connection_close_possibly_shared (connection);
503 dbus_connection_unref (connection);
510 /* store a weak ref to the connection (dbus-connection.c is
511 * supposed to have a strong ref that it drops on disconnect,
512 * since this is a shared connection)
514 bus_connections[type] = connection;
517 /* By default we're bound to the lifecycle of
520 dbus_connection_set_exit_on_disconnect (connection,
523 if (!_DBUS_LOCK (bus_datas))
524 _dbus_assert_not_reached ("global locks were initialized already");
526 bd = ensure_bus_data (connection);
527 _dbus_assert (bd != NULL); /* it should have been created on
528 register, so OOM not possible */
529 bd->is_well_known = TRUE;
530 _DBUS_UNLOCK (bus_datas);
533 /* Return a reference to the caller, or NULL with error set. */
534 if (connection == NULL)
535 _DBUS_ASSERT_ERROR_IS_SET (error);
542 /** @} */ /* end of implementation details docs */
545 * @addtogroup DBusBus
550 * Connects to a bus daemon and registers the client with it. If a
551 * connection to the bus already exists, then that connection is
552 * returned. The caller of this function owns a reference to the bus.
554 * The caller may NOT call dbus_connection_close() on this connection;
555 * see dbus_connection_open() and dbus_connection_close() for details
558 * If this function obtains a new connection object never before
559 * returned from dbus_bus_get(), it will call
560 * dbus_connection_set_exit_on_disconnect(), so the application
561 * will exit if the connection closes. You can undo this
562 * by calling dbus_connection_set_exit_on_disconnect() yourself
563 * after you get the connection.
565 * dbus_bus_get() calls dbus_bus_register() for you.
567 * If returning a newly-created connection, this function will block
568 * until authentication and bus registration are complete.
570 * @param type bus type
571 * @param error address where an error can be returned.
572 * @returns a #DBusConnection with new ref or #NULL on error
575 dbus_bus_get (DBusBusType type,
578 return internal_bus_get (type, FALSE, error);
582 * Connects to a bus daemon and registers the client with it as with
583 * dbus_bus_register(). Unlike dbus_bus_get(), always creates a new
584 * connection. This connection will not be saved or recycled by
585 * libdbus. Caller owns a reference to the bus and must either close
586 * it or know it to be closed prior to releasing this reference.
588 * See dbus_connection_open_private() for more details on when to
589 * close and unref this connection.
591 * This function calls
592 * dbus_connection_set_exit_on_disconnect() on the new connection, so the application
593 * will exit if the connection closes. You can undo this
594 * by calling dbus_connection_set_exit_on_disconnect() yourself
595 * after you get the connection.
597 * dbus_bus_get_private() calls dbus_bus_register() for you.
599 * This function will block until authentication and bus registration
602 * @param type bus type
603 * @param error address where an error can be returned.
604 * @returns a DBusConnection with new ref
607 dbus_bus_get_private (DBusBusType type,
610 return internal_bus_get (type, TRUE, error);
614 * Registers a connection with the bus. This must be the first
615 * thing an application does when connecting to the message bus.
616 * If registration succeeds, the unique name will be set,
617 * and can be obtained using dbus_bus_get_unique_name().
619 * This function will block until registration is complete.
621 * If the connection has already registered with the bus
622 * (determined by checking whether dbus_bus_get_unique_name()
623 * returns a non-#NULL value), then this function does nothing.
625 * If you use dbus_bus_get() or dbus_bus_get_private() this
626 * function will be called for you.
628 * @note Just use dbus_bus_get() or dbus_bus_get_private() instead of
629 * dbus_bus_register() and save yourself some pain. Using
630 * dbus_bus_register() manually is only useful if you have your
631 * own custom message bus not found in #DBusBusType.
633 * If you open a bus connection with dbus_connection_open() or
634 * dbus_connection_open_private() you will have to dbus_bus_register()
635 * yourself, or make the appropriate registration method calls
636 * yourself. If you send the method calls yourself, call
637 * dbus_bus_set_unique_name() with the unique bus name you get from
640 * For shared connections (created with dbus_connection_open()) in a
641 * multithreaded application, you can't really make the registration
642 * calls yourself, because you don't know whether some other thread is
643 * also registering, and the bus will kick you off if you send two
644 * registration messages.
646 * If you use dbus_bus_register() however, there is a lock that
647 * keeps both apps from registering at the same time.
649 * The rule in a multithreaded app, then, is that dbus_bus_register()
650 * must be used to register, or you need to have your own locks that
651 * all threads in the app will respect.
653 * In a single-threaded application you can register by hand instead
654 * of using dbus_bus_register(), as long as you check
655 * dbus_bus_get_unique_name() to see if a unique name has already been
656 * stored by another thread before you send the registration messages.
658 * @param connection the connection
659 * @param error place to store errors
660 * @returns #TRUE on success
663 dbus_bus_register (DBusConnection *connection,
666 DBusMessage *message, *reply;
671 _dbus_return_val_if_fail (connection != NULL, FALSE);
672 _dbus_return_val_if_error_is_set (error, FALSE);
678 if (!_DBUS_LOCK (bus_datas))
680 _DBUS_SET_OOM (error);
681 /* do not "goto out", that would try to unlock */
685 bd = ensure_bus_data (connection);
688 _DBUS_SET_OOM (error);
692 if (bd->unique_name != NULL)
694 _dbus_verbose ("Ignoring attempt to register the same DBusConnection %s with the message bus a second time.\n",
700 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
706 _DBUS_SET_OOM (error);
710 reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
714 else if (dbus_set_error_from_message (error, reply))
716 else if (!dbus_message_get_args (reply, error,
717 DBUS_TYPE_STRING, &name,
721 bd->unique_name = _dbus_strdup (name);
723 if (bd->unique_name == NULL)
725 _DBUS_SET_OOM (error);
728 //_dbus_verbose("-- Our uniqe name is: %s\n", bd->unique_name);
732 _DBUS_UNLOCK (bus_datas);
735 dbus_message_unref (message);
740 dbus_message_unref (reply);
743 _DBUS_ASSERT_ERROR_IS_SET (error);
750 * Sets the unique name of the connection, as assigned by the message
751 * bus. Can only be used if you registered with the bus manually
752 * (i.e. if you did not call dbus_bus_register()). Can only be called
753 * once per connection. After the unique name is set, you can get it
754 * with dbus_bus_get_unique_name().
756 * The only reason to use this function is to re-implement the
757 * equivalent of dbus_bus_register() yourself. One (probably unusual)
758 * reason to do that might be to do the bus registration call
759 * asynchronously instead of synchronously.
761 * @note Just use dbus_bus_get() or dbus_bus_get_private(), or worst
762 * case dbus_bus_register(), instead of messing with this
763 * function. There's really no point creating pain for yourself by
764 * doing things manually.
766 * It's hard to use this function safely on shared connections
767 * (created by dbus_connection_open()) in a multithreaded application,
768 * because only one registration attempt can be sent to the bus. If
769 * two threads are both sending the registration message, there is no
770 * mechanism in libdbus itself to avoid sending it twice.
772 * Thus, you need a way to coordinate which thread sends the
773 * registration attempt; which also means you know which thread
774 * will call dbus_bus_set_unique_name(). If you don't know
775 * about all threads in the app (for example, if some libraries
776 * you're using might start libdbus-using threads), then you
777 * need to avoid using this function on shared connections.
779 * @param connection the connection
780 * @param unique_name the unique name
781 * @returns #FALSE if not enough memory
784 dbus_bus_set_unique_name (DBusConnection *connection,
785 const char *unique_name)
788 dbus_bool_t success = FALSE;
790 _dbus_return_val_if_fail (connection != NULL, FALSE);
791 _dbus_return_val_if_fail (unique_name != NULL, FALSE);
793 if (!_DBUS_LOCK (bus_datas))
795 /* do not "goto out", that would try to unlock */
799 bd = ensure_bus_data (connection);
803 _dbus_assert (bd->unique_name == NULL);
805 bd->unique_name = _dbus_strdup (unique_name);
806 success = bd->unique_name != NULL;
809 _DBUS_UNLOCK (bus_datas);
815 * Gets the unique name of the connection as assigned by the message
816 * bus. Only possible after the connection has been registered with
817 * the message bus. All connections returned by dbus_bus_get() or
818 * dbus_bus_get_private() have been successfully registered.
820 * The name remains valid until the connection is freed, and
821 * should not be freed by the caller.
823 * Other than dbus_bus_get(), there are two ways to set the unique
824 * name; one is dbus_bus_register(), the other is
825 * dbus_bus_set_unique_name(). You are responsible for calling
826 * dbus_bus_set_unique_name() if you register by hand instead of using
827 * dbus_bus_register().
829 * @param connection the connection
830 * @returns the unique name or #NULL on error
833 dbus_bus_get_unique_name (DBusConnection *connection)
836 const char *unique_name = NULL;
838 _dbus_return_val_if_fail (connection != NULL, NULL);
840 if (!_DBUS_LOCK (bus_datas))
842 /* We'd have initialized locks when we gave it its unique name, if it
843 * had one. Don't "goto out", that would try to unlock. */
847 bd = ensure_bus_data (connection);
851 unique_name = bd->unique_name;
854 _DBUS_UNLOCK (bus_datas);
860 * Asks the bus to return the UID the named connection authenticated
861 * as, if any. Only works on UNIX; only works for connections on the
862 * same machine as the bus. If you are not on the same machine as the
863 * bus, then calling this is probably a bad idea, since the UID will
864 * mean little to your application.
866 * For the system message bus you're guaranteed to be on the same
867 * machine since it only listens on a UNIX domain socket (at least,
868 * as shipped by default).
870 * This function only works for connections that authenticated as
871 * a UNIX user, right now that includes all bus connections, but
872 * it's very possible to have connections with no associated UID.
873 * So check for errors and do something sensible if they happen.
875 * This function will always return an error on Windows.
877 * @param connection the connection
878 * @param name a name owned by the connection
879 * @param error location to store the error
880 * @returns the unix user id, or ((unsigned)-1) if error is set
883 dbus_bus_get_unix_user (DBusConnection *connection,
887 DBusMessage *message, *reply;
890 _dbus_return_val_if_fail (connection != NULL, DBUS_UID_UNSET);
891 _dbus_return_val_if_fail (name != NULL, DBUS_UID_UNSET);
892 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), DBUS_UID_UNSET);
893 _dbus_return_val_if_error_is_set (error, DBUS_UID_UNSET);
895 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
898 "GetConnectionUnixUser");
902 _DBUS_SET_OOM (error);
903 return DBUS_UID_UNSET;
906 if (!dbus_message_append_args (message,
907 DBUS_TYPE_STRING, &name,
910 dbus_message_unref (message);
911 _DBUS_SET_OOM (error);
912 return DBUS_UID_UNSET;
915 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
918 dbus_message_unref (message);
922 _DBUS_ASSERT_ERROR_IS_SET (error);
923 return DBUS_UID_UNSET;
926 if (dbus_set_error_from_message (error, reply))
928 _DBUS_ASSERT_ERROR_IS_SET (error);
929 dbus_message_unref (reply);
930 return DBUS_UID_UNSET;
933 if (!dbus_message_get_args (reply, error,
934 DBUS_TYPE_UINT32, &uid,
937 _DBUS_ASSERT_ERROR_IS_SET (error);
938 dbus_message_unref (reply);
939 return DBUS_UID_UNSET;
942 dbus_message_unref (reply);
944 return (unsigned long) uid;
948 * Asks the bus to return its globally unique ID, as described in the
949 * D-Bus specification. For the session bus, this is useful as a way
950 * to uniquely identify each user session. For the system bus,
951 * probably the bus ID is not useful; instead, use the machine ID
952 * since it's accessible without necessarily connecting to the bus and
953 * may be persistent beyond a single bus instance (across reboots for
954 * example). See dbus_get_local_machine_id().
956 * In addition to an ID for each bus and an ID for each machine, there is
957 * an ID for each address that the bus is listening on; that can
958 * be retrieved with dbus_connection_get_server_id(), though it is
959 * probably not very useful.
961 * @param connection the connection
962 * @param error location to store the error
963 * @returns the bus ID or #NULL if error is set
966 dbus_bus_get_id (DBusConnection *connection,
969 DBusMessage *message, *reply;
971 const char *v_STRING;
973 _dbus_return_val_if_fail (connection != NULL, NULL);
974 _dbus_return_val_if_error_is_set (error, NULL);
976 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
983 _DBUS_SET_OOM (error);
987 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
990 dbus_message_unref (message);
994 _DBUS_ASSERT_ERROR_IS_SET (error);
998 if (dbus_set_error_from_message (error, reply))
1000 _DBUS_ASSERT_ERROR_IS_SET (error);
1001 dbus_message_unref (reply);
1006 if (!dbus_message_get_args (reply, error,
1007 DBUS_TYPE_STRING, &v_STRING,
1010 _DBUS_ASSERT_ERROR_IS_SET (error);
1011 dbus_message_unref (reply);
1015 id = _dbus_strdup (v_STRING); /* may be NULL */
1017 dbus_message_unref (reply);
1020 _DBUS_SET_OOM (error);
1022 /* FIXME it might be nice to cache the ID locally */
1028 * Asks the bus to assign the given name to this connection by invoking
1029 * the RequestName method on the bus. This method is fully documented
1030 * in the D-Bus specification. For quick reference, the flags and
1031 * result codes are discussed here, but the specification is the
1032 * canonical version of this information.
1034 * First you should know that for each bus name, the bus stores
1035 * a queue of connections that would like to own it. Only
1036 * one owns it at a time - called the primary owner. If the primary
1037 * owner releases the name or disconnects, then the next owner in the
1038 * queue atomically takes over.
1040 * So for example if you have an application org.freedesktop.TextEditor
1041 * and multiple instances of it can be run, you can have all of them
1042 * sitting in the queue. The first one to start up will receive messages
1043 * sent to org.freedesktop.TextEditor, but if that one exits another
1044 * will become the primary owner and receive messages.
1046 * The queue means you don't need to manually watch for the current owner to
1047 * disappear and then request the name again.
1049 * When requesting a name, you can specify several flags.
1051 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT and #DBUS_NAME_FLAG_DO_NOT_QUEUE
1052 * are properties stored by the bus for this connection with respect to
1053 * each requested bus name. These properties are stored even if the
1054 * connection is queued and does not become the primary owner.
1055 * You can update these flags by calling RequestName again (even if
1056 * you already own the name).
1058 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT means that another requestor of the
1059 * name can take it away from you by specifying #DBUS_NAME_FLAG_REPLACE_EXISTING.
1061 * #DBUS_NAME_FLAG_DO_NOT_QUEUE means that if you aren't the primary owner,
1062 * you don't want to be queued up - you only care about being the
1065 * Unlike the other two flags, #DBUS_NAME_FLAG_REPLACE_EXISTING is a property
1066 * of the individual RequestName call, i.e. the bus does not persistently
1067 * associate it with the connection-name pair. If a RequestName call includes
1068 * the #DBUS_NAME_FLAG_REPLACE_EXISTING flag, and the current primary
1069 * owner has #DBUS_NAME_FLAG_ALLOW_REPLACEMENT set, then the current primary
1070 * owner will be kicked off.
1072 * If no flags are given, an application will receive the requested
1073 * name only if the name is currently unowned; and it will NOT give
1074 * up the name if another application asks to take it over using
1075 * #DBUS_NAME_FLAG_REPLACE_EXISTING.
1077 * This function returns a result code. The possible result codes
1080 * #DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER means that the name had no
1081 * existing owner, and the caller is now the primary owner; or that
1082 * the name had an owner, and the caller specified
1083 * #DBUS_NAME_FLAG_REPLACE_EXISTING, and the current owner
1084 * specified #DBUS_NAME_FLAG_ALLOW_REPLACEMENT.
1086 * #DBUS_REQUEST_NAME_REPLY_IN_QUEUE happens only if the caller does NOT
1087 * specify #DBUS_NAME_FLAG_DO_NOT_QUEUE and either the current owner
1088 * did NOT specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT
1089 * specify #DBUS_NAME_FLAG_REPLACE_EXISTING. In this case the caller ends up
1090 * in a queue to own the name after the current owner gives it up.
1092 * #DBUS_REQUEST_NAME_REPLY_EXISTS happens if the name has an owner
1093 * already and the caller specifies #DBUS_NAME_FLAG_DO_NOT_QUEUE
1094 * and either the current owner has NOT specified
1095 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT specify
1096 * #DBUS_NAME_FLAG_REPLACE_EXISTING.
1098 * #DBUS_REQUEST_NAME_REPLY_ALREADY_OWNER happens if an application
1099 * requests a name it already owns. (Re-requesting a name is useful if
1100 * you want to change the #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or
1101 * #DBUS_NAME_FLAG_DO_NOT_QUEUE settings.)
1103 * When a service represents an application, say "text editor," then
1104 * it should specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT if it wants
1105 * the last editor started to be the user's editor vs. the first one
1106 * started. Then any editor that can be the user's editor should
1107 * specify #DBUS_NAME_FLAG_REPLACE_EXISTING to either take over
1108 * (last-started-wins) or be queued up (first-started-wins) according
1109 * to whether #DBUS_NAME_FLAG_ALLOW_REPLACEMENT was given.
1111 * Conventionally, single-instance applications often offer a command
1112 * line option called --replace which means to replace the current
1113 * instance. To implement this, always set
1114 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT when you request your
1115 * application's bus name. When you lose ownership of your bus name,
1116 * you need to exit. Look for the signal "NameLost" from
1117 * #DBUS_SERVICE_DBUS and #DBUS_INTERFACE_DBUS (the signal's first
1118 * argument is the bus name that was lost). If starting up without
1119 * --replace, do not specify #DBUS_NAME_FLAG_REPLACE_EXISTING, and
1120 * exit if you fail to become the bus name owner. If --replace is
1121 * given, ask to replace the old owner.
1123 * @param connection the connection
1124 * @param name the name to request
1125 * @param flags flags
1126 * @param error location to store the error
1127 * @returns a result code, -1 if error is set
1130 dbus_bus_request_name (DBusConnection *connection,
1135 dbus_uint32_t result;
1136 DBusMessage *message, *reply;
1138 _dbus_return_val_if_fail (connection != NULL, 0);
1139 _dbus_return_val_if_fail (name != NULL, 0);
1140 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0);
1141 _dbus_return_val_if_error_is_set (error, 0);
1143 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1145 DBUS_INTERFACE_DBUS,
1147 if (message == NULL)
1149 _DBUS_SET_OOM (error);
1153 if (!dbus_message_append_args (message,
1154 DBUS_TYPE_STRING, &name,
1155 DBUS_TYPE_UINT32, &flags,
1158 dbus_message_unref (message);
1159 _DBUS_SET_OOM (error);
1163 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
1166 dbus_message_unref (message);
1170 _DBUS_ASSERT_ERROR_IS_SET (error);
1174 if (dbus_set_error_from_message (error, reply))
1176 _DBUS_ASSERT_ERROR_IS_SET (error);
1177 dbus_message_unref (reply);
1181 if (!dbus_message_get_args (reply, error,
1182 DBUS_TYPE_UINT32, &result,
1185 _DBUS_ASSERT_ERROR_IS_SET (error);
1186 dbus_message_unref (reply);
1190 dbus_message_unref (reply);
1196 * Asks the bus to unassign the given name from this connection by
1197 * invoking the ReleaseName method on the bus. The "ReleaseName"
1198 * method is canonically documented in the D-Bus specification.
1200 * Possible results are: #DBUS_RELEASE_NAME_REPLY_RELEASED
1201 * which means you owned the name or were in the queue to own it,
1202 * and and now you don't own it and aren't in the queue.
1203 * #DBUS_RELEASE_NAME_REPLY_NOT_OWNER which means someone else
1204 * owns the name so you can't release it.
1205 * #DBUS_RELEASE_NAME_REPLY_NON_EXISTENT
1206 * which means nobody owned the name.
1208 * @param connection the connection
1209 * @param name the name to remove
1210 * @param error location to store the error
1211 * @returns a result code, -1 if error is set
1214 dbus_bus_release_name (DBusConnection *connection,
1218 DBusMessage *message, *reply;
1219 dbus_uint32_t result;
1221 _dbus_return_val_if_fail (connection != NULL, 0);
1222 _dbus_return_val_if_fail (name != NULL, 0);
1223 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0);
1224 _dbus_return_val_if_error_is_set (error, 0);
1226 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1228 DBUS_INTERFACE_DBUS,
1231 if (message == NULL)
1233 _DBUS_SET_OOM (error);
1237 if (!dbus_message_append_args (message,
1238 DBUS_TYPE_STRING, &name,
1241 dbus_message_unref (message);
1242 _DBUS_SET_OOM (error);
1246 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
1249 dbus_message_unref (message);
1253 _DBUS_ASSERT_ERROR_IS_SET (error);
1257 if (dbus_set_error_from_message (error, reply))
1259 _DBUS_ASSERT_ERROR_IS_SET (error);
1260 dbus_message_unref (reply);
1264 if (!dbus_message_get_args (reply, error,
1265 DBUS_TYPE_UINT32, &result,
1268 _DBUS_ASSERT_ERROR_IS_SET (error);
1269 dbus_message_unref (reply);
1273 dbus_message_unref (reply);
1279 * Asks the bus whether a certain name has an owner.
1281 * Using this can easily result in a race condition,
1282 * since an owner can appear or disappear after you
1285 * If you want to request a name, just request it;
1286 * if you want to avoid replacing a current owner,
1287 * don't specify #DBUS_NAME_FLAG_REPLACE_EXISTING and
1288 * you will get an error if there's already an owner.
1290 * @param connection the connection
1291 * @param name the name
1292 * @param error location to store any errors
1293 * @returns #TRUE if the name exists, #FALSE if not or on error
1296 dbus_bus_name_has_owner (DBusConnection *connection,
1300 DBusMessage *message, *reply;
1303 _dbus_return_val_if_fail (connection != NULL, FALSE);
1304 _dbus_return_val_if_fail (name != NULL, FALSE);
1305 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE);
1306 _dbus_return_val_if_error_is_set (error, FALSE);
1308 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1310 DBUS_INTERFACE_DBUS,
1312 if (message == NULL)
1314 _DBUS_SET_OOM (error);
1318 if (!dbus_message_append_args (message,
1319 DBUS_TYPE_STRING, &name,
1322 dbus_message_unref (message);
1323 _DBUS_SET_OOM (error);
1327 reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
1328 dbus_message_unref (message);
1332 _DBUS_ASSERT_ERROR_IS_SET (error);
1336 if (!dbus_message_get_args (reply, error,
1337 DBUS_TYPE_BOOLEAN, &exists,
1340 _DBUS_ASSERT_ERROR_IS_SET (error);
1341 dbus_message_unref (reply);
1345 dbus_message_unref (reply);
1350 * Starts a service that will request ownership of the given name.
1351 * The returned result will be one of be one of
1352 * #DBUS_START_REPLY_SUCCESS or #DBUS_START_REPLY_ALREADY_RUNNING if
1353 * successful. Pass #NULL if you don't care about the result.
1355 * The flags parameter is for future expansion, currently you should
1358 * It's often easier to avoid explicitly starting services, and
1359 * just send a method call to the service's bus name instead.
1360 * Method calls start a service to handle them by default
1361 * unless you call dbus_message_set_auto_start() to disable this
1364 * @param connection the connection
1365 * @param name the name we want the new service to request
1366 * @param flags the flags (should always be 0 for now)
1367 * @param result a place to store the result or #NULL
1368 * @param error location to store any errors
1369 * @returns #TRUE if the activation succeeded, #FALSE if not
1372 dbus_bus_start_service_by_name (DBusConnection *connection,
1374 dbus_uint32_t flags,
1375 dbus_uint32_t *result,
1381 _dbus_return_val_if_fail (connection != NULL, FALSE);
1382 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE);
1384 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1386 DBUS_INTERFACE_DBUS,
1387 "StartServiceByName");
1389 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &name,
1390 DBUS_TYPE_UINT32, &flags, DBUS_TYPE_INVALID))
1392 dbus_message_unref (msg);
1393 _DBUS_SET_OOM (error);
1397 reply = dbus_connection_send_with_reply_and_block (connection, msg,
1399 dbus_message_unref (msg);
1403 _DBUS_ASSERT_ERROR_IS_SET (error);
1407 if (dbus_set_error_from_message (error, reply))
1409 _DBUS_ASSERT_ERROR_IS_SET (error);
1410 dbus_message_unref (reply);
1414 if (result != NULL &&
1415 !dbus_message_get_args (reply, error, DBUS_TYPE_UINT32,
1416 result, DBUS_TYPE_INVALID))
1418 _DBUS_ASSERT_ERROR_IS_SET (error);
1419 dbus_message_unref (reply);
1423 dbus_message_unref (reply);
1428 send_no_return_values (DBusConnection *connection,
1434 /* Block to check success codepath */
1437 reply = dbus_connection_send_with_reply_and_block (connection, msg,
1441 _DBUS_ASSERT_ERROR_IS_SET (error);
1443 dbus_message_unref (reply);
1447 /* Silently-fail nonblocking codepath */
1448 dbus_message_set_no_reply (msg, TRUE);
1449 dbus_connection_send (connection, msg, NULL);
1454 * Adds a match rule to match messages going through the message bus.
1455 * The "rule" argument is the string form of a match rule.
1457 * If you pass #NULL for the error, this function will not
1458 * block; the match thus won't be added until you flush the
1459 * connection, and if there's an error adding the match
1460 * you won't find out about it. This is generally acceptable, since the
1461 * possible errors (including a lack of resources in the bus, the connection
1462 * having exceeded its quota of active match rules, or the match rule being
1463 * unparseable) are generally unrecoverable.
1465 * If you pass non-#NULL for the error this function will
1466 * block until it gets a reply. This may be useful when using match rule keys
1467 * introduced in recent versions of D-Bus, like 'arg0namespace', to allow the
1468 * application to fall back to less efficient match rules supported by older
1469 * versions of the daemon if the running version is not new enough; or when
1470 * using user-supplied rules rather than rules hard-coded at compile time.
1472 * Normal API conventions would have the function return
1473 * a boolean value indicating whether the error was set,
1474 * but that would require blocking always to determine
1477 * The AddMatch method is fully documented in the D-Bus
1478 * specification. For quick reference, the format of the
1479 * match rules is discussed here, but the specification
1480 * is the canonical version of this information.
1482 * Rules are specified as a string of comma separated
1483 * key/value pairs. An example is
1484 * "type='signal',sender='org.freedesktop.DBus',
1485 * interface='org.freedesktop.DBus',member='Foo',
1486 * path='/bar/foo',destination=':452345.34'"
1488 * Possible keys you can match on are type, sender,
1489 * interface, member, path, destination and numbered
1490 * keys to match message args (keys are 'arg0', 'arg1', etc.).
1491 * Omitting a key from the rule indicates
1492 * a wildcard match. For instance omitting
1493 * the member from a match rule but adding a sender would
1494 * let all messages from that sender through regardless of
1497 * Matches are inclusive not exclusive so as long as one
1498 * rule matches the message will get through. It is important
1499 * to note this because every time a message is received the
1500 * application will be paged into memory to process it. This
1501 * can cause performance problems such as draining batteries
1502 * on embedded platforms.
1504 * If you match message args ('arg0', 'arg1', and so forth)
1505 * only string arguments will match. That is, arg0='5' means
1506 * match the string "5" not the integer 5.
1508 * Currently there is no way to match against non-string arguments.
1510 * A specialised form of wildcard matching on arguments is
1511 * supported for path-like namespaces. If your argument match has
1512 * a 'path' suffix (eg: "arg0path='/some/path/'") then it is
1513 * considered a match if the argument exactly matches the given
1514 * string or if one of them ends in a '/' and is a prefix of the
1517 * Matching on interface is tricky because method call
1518 * messages only optionally specify the interface.
1519 * If a message omits the interface, then it will NOT match
1520 * if the rule specifies an interface name. This means match
1521 * rules on method calls should not usually give an interface.
1523 * However, signal messages are required to include the interface
1524 * so when matching signals usually you should specify the interface
1525 * in the match rule.
1527 * For security reasons, you can match arguments only up to
1528 * #DBUS_MAXIMUM_MATCH_RULE_ARG_NUMBER.
1530 * Match rules have a maximum length of #DBUS_MAXIMUM_MATCH_RULE_LENGTH
1533 * Both of these maximums are much higher than you're likely to need,
1534 * they only exist because the D-Bus bus daemon has fixed limits on
1535 * all resource usage.
1537 * @param connection connection to the message bus
1538 * @param rule textual form of match rule
1539 * @param error location to store any errors
1542 dbus_bus_add_match (DBusConnection *connection,
1548 _dbus_return_if_fail (rule != NULL);
1550 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1552 DBUS_INTERFACE_DBUS,
1557 _DBUS_SET_OOM (error);
1561 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &rule,
1564 dbus_message_unref (msg);
1565 _DBUS_SET_OOM (error);
1569 send_no_return_values (connection, msg, error);
1571 dbus_message_unref (msg);
1575 * Removes a previously-added match rule "by value" (the most
1576 * recently-added identical rule gets removed). The "rule" argument
1577 * is the string form of a match rule.
1579 * The bus compares match rules semantically, not textually, so
1580 * whitespace and ordering don't have to be identical to
1581 * the rule you passed to dbus_bus_add_match().
1583 * If you pass #NULL for the error, this function will not
1584 * block; otherwise it will. See detailed explanation in
1585 * docs for dbus_bus_add_match().
1587 * @param connection connection to the message bus
1588 * @param rule textual form of match rule
1589 * @param error location to store any errors
1592 dbus_bus_remove_match (DBusConnection *connection,
1598 _dbus_return_if_fail (rule != NULL);
1600 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1602 DBUS_INTERFACE_DBUS,
1605 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &rule,
1608 dbus_message_unref (msg);
1609 _DBUS_SET_OOM (error);
1613 send_no_return_values (connection, msg, error);
1615 dbus_message_unref (msg);