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.\n");
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\n", error.message);
173 _dbus_warn ("Dynamic session lookup supported but failed silently\n");
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 /* If we return FALSE we have to be sure that restarting
294 * the above code will work right
297 if (!dbus_setenv ("DBUS_ACTIVATION_ADDRESS", NULL))
300 if (!dbus_setenv ("DBUS_ACTIVATION_BUS_TYPE", NULL))
303 if (!_dbus_register_shutdown_func (addresses_shutdown_func,
314 bus_data_free (void *data)
318 if (bd->is_well_known)
322 if (!_DBUS_LOCK (bus))
323 _dbus_assert_not_reached ("global locks should have been initialized "
324 "when we attached bus data");
326 /* We may be stored in more than one slot */
327 /* This should now be impossible - these slots are supposed to
328 * be cleared on disconnect, so should not need to be cleared on
332 while (i < N_BUS_TYPES)
334 if (bus_connections[i] == bd->connection)
335 bus_connections[i] = NULL;
342 dbus_free (bd->unique_name);
345 dbus_connection_free_data_slot (&bus_data_slot);
349 ensure_bus_data (DBusConnection *connection)
353 if (!dbus_connection_allocate_data_slot (&bus_data_slot))
356 bd = dbus_connection_get_data (connection, bus_data_slot);
359 bd = dbus_new0 (BusData, 1);
362 dbus_connection_free_data_slot (&bus_data_slot);
366 bd->connection = connection;
368 if (!dbus_connection_set_data (connection, bus_data_slot, bd,
372 dbus_connection_free_data_slot (&bus_data_slot);
376 /* Data slot refcount now held by the BusData */
380 dbus_connection_free_data_slot (&bus_data_slot);
387 * Internal function that checks to see if this
388 * is a shared connection owned by the bus and if it is unref it.
390 * @param connection a connection that has been disconnected.
393 _dbus_bus_notify_shared_connection_disconnected_unlocked (DBusConnection *connection)
397 if (!_DBUS_LOCK (bus))
399 /* If it was in bus_connections, we would have initialized global locks
400 * when we added it. So, it can't be. */
404 /* We are expecting to have the connection saved in only one of these
405 * slots, but someone could in a pathological case set system and session
406 * bus to the same bus or something. Or set one of them to the starter
407 * bus without setting the starter bus type in the env variable.
408 * So we don't break the loop as soon as we find a match.
410 for (i = 0; i < N_BUS_TYPES; ++i)
412 if (bus_connections[i] == connection)
414 bus_connections[i] = NULL;
421 static DBusConnection *
422 internal_bus_get (DBusBusType type,
427 DBusConnection *connection;
429 DBusBusType address_type;
431 _dbus_return_val_if_fail (type >= 0 && type < N_BUS_TYPES, NULL);
432 _dbus_return_val_if_error_is_set (error, NULL);
436 if (!_DBUS_LOCK (bus))
438 _DBUS_SET_OOM (error);
439 /* do not "goto out", that would try to unlock */
443 if (!init_connections_unlocked ())
445 _DBUS_SET_OOM (error);
449 /* We want to use the activation address even if the
450 * activating bus is the session or system bus,
455 /* Use the real type of the activation bus for getting its
456 * connection, but only if the real type's address is available. (If
457 * the activating bus isn't a well-known bus then
458 * activation_bus_type == DBUS_BUS_STARTER)
460 if (type == DBUS_BUS_STARTER &&
461 bus_connection_addresses[activation_bus_type] != NULL)
462 type = activation_bus_type;
464 if (!private && bus_connections[type] != NULL)
466 connection = bus_connections[type];
467 dbus_connection_ref (connection);
471 address = bus_connection_addresses[address_type];
474 dbus_set_error (error, DBUS_ERROR_FAILED,
475 "Unable to determine the address of the message bus (try 'man dbus-launch' and 'man dbus-daemon' for help)");
480 connection = dbus_connection_open_private (address, error);
482 connection = dbus_connection_open (address, error);
489 if (!dbus_bus_register (connection, error))
491 _dbus_connection_close_possibly_shared (connection);
492 dbus_connection_unref (connection);
499 /* store a weak ref to the connection (dbus-connection.c is
500 * supposed to have a strong ref that it drops on disconnect,
501 * since this is a shared connection)
503 bus_connections[type] = connection;
506 /* By default we're bound to the lifecycle of
509 dbus_connection_set_exit_on_disconnect (connection,
512 if (!_DBUS_LOCK (bus_datas))
513 _dbus_assert_not_reached ("global locks were initialized already");
515 bd = ensure_bus_data (connection);
516 _dbus_assert (bd != NULL); /* it should have been created on
517 register, so OOM not possible */
518 bd->is_well_known = TRUE;
519 _DBUS_UNLOCK (bus_datas);
522 /* Return a reference to the caller, or NULL with error set. */
523 if (connection == NULL)
524 _DBUS_ASSERT_ERROR_IS_SET (error);
531 /** @} */ /* end of implementation details docs */
534 * @addtogroup DBusBus
539 * Connects to a bus daemon and registers the client with it. If a
540 * connection to the bus already exists, then that connection is
541 * returned. The caller of this function owns a reference to the bus.
543 * The caller may NOT call dbus_connection_close() on this connection;
544 * see dbus_connection_open() and dbus_connection_close() for details
547 * If this function obtains a new connection object never before
548 * returned from dbus_bus_get(), it will call
549 * dbus_connection_set_exit_on_disconnect(), so the application
550 * will exit if the connection closes. You can undo this
551 * by calling dbus_connection_set_exit_on_disconnect() yourself
552 * after you get the connection.
554 * dbus_bus_get() calls dbus_bus_register() for you.
556 * If returning a newly-created connection, this function will block
557 * until authentication and bus registration are complete.
559 * @param type bus type
560 * @param error address where an error can be returned.
561 * @returns a #DBusConnection with new ref or #NULL on error
564 dbus_bus_get (DBusBusType type,
567 return internal_bus_get (type, FALSE, error);
571 * Connects to a bus daemon and registers the client with it as with
572 * dbus_bus_register(). Unlike dbus_bus_get(), always creates a new
573 * connection. This connection will not be saved or recycled by
574 * libdbus. Caller owns a reference to the bus and must either close
575 * it or know it to be closed prior to releasing this reference.
577 * See dbus_connection_open_private() for more details on when to
578 * close and unref this connection.
580 * This function calls
581 * dbus_connection_set_exit_on_disconnect() on the new connection, so the application
582 * will exit if the connection closes. You can undo this
583 * by calling dbus_connection_set_exit_on_disconnect() yourself
584 * after you get the connection.
586 * dbus_bus_get_private() calls dbus_bus_register() for you.
588 * This function will block until authentication and bus registration
591 * @param type bus type
592 * @param error address where an error can be returned.
593 * @returns a DBusConnection with new ref
596 dbus_bus_get_private (DBusBusType type,
599 return internal_bus_get (type, TRUE, error);
603 * Registers a connection with the bus. This must be the first
604 * thing an application does when connecting to the message bus.
605 * If registration succeeds, the unique name will be set,
606 * and can be obtained using dbus_bus_get_unique_name().
608 * This function will block until registration is complete.
610 * If the connection has already registered with the bus
611 * (determined by checking whether dbus_bus_get_unique_name()
612 * returns a non-#NULL value), then this function does nothing.
614 * If you use dbus_bus_get() or dbus_bus_get_private() this
615 * function will be called for you.
617 * @note Just use dbus_bus_get() or dbus_bus_get_private() instead of
618 * dbus_bus_register() and save yourself some pain. Using
619 * dbus_bus_register() manually is only useful if you have your
620 * own custom message bus not found in #DBusBusType.
622 * If you open a bus connection with dbus_connection_open() or
623 * dbus_connection_open_private() you will have to dbus_bus_register()
624 * yourself, or make the appropriate registration method calls
625 * yourself. If you send the method calls yourself, call
626 * dbus_bus_set_unique_name() with the unique bus name you get from
629 * For shared connections (created with dbus_connection_open()) in a
630 * multithreaded application, you can't really make the registration
631 * calls yourself, because you don't know whether some other thread is
632 * also registering, and the bus will kick you off if you send two
633 * registration messages.
635 * If you use dbus_bus_register() however, there is a lock that
636 * keeps both apps from registering at the same time.
638 * The rule in a multithreaded app, then, is that dbus_bus_register()
639 * must be used to register, or you need to have your own locks that
640 * all threads in the app will respect.
642 * In a single-threaded application you can register by hand instead
643 * of using dbus_bus_register(), as long as you check
644 * dbus_bus_get_unique_name() to see if a unique name has already been
645 * stored by another thread before you send the registration messages.
647 * @param connection the connection
648 * @param error place to store errors
649 * @returns #TRUE on success
652 dbus_bus_register (DBusConnection *connection,
655 DBusMessage *message, *reply;
660 _dbus_return_val_if_fail (connection != NULL, FALSE);
661 _dbus_return_val_if_error_is_set (error, FALSE);
667 if (!_DBUS_LOCK (bus_datas))
669 _DBUS_SET_OOM (error);
670 /* do not "goto out", that would try to unlock */
674 bd = ensure_bus_data (connection);
677 _DBUS_SET_OOM (error);
681 if (bd->unique_name != NULL)
683 _dbus_verbose ("Ignoring attempt to register the same DBusConnection %s with the message bus a second time.\n",
690 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
697 _DBUS_SET_OOM (error);
701 reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
705 else if (dbus_set_error_from_message (error, reply))
707 else if (!dbus_message_get_args (reply, error,
708 DBUS_TYPE_STRING, &name,
712 bd->unique_name = _dbus_strdup (name);
713 if (bd->unique_name == NULL)
715 _DBUS_SET_OOM (error);
722 _DBUS_UNLOCK (bus_datas);
725 dbus_message_unref (message);
728 dbus_message_unref (reply);
731 _DBUS_ASSERT_ERROR_IS_SET (error);
738 * Sets the unique name of the connection, as assigned by the message
739 * bus. Can only be used if you registered with the bus manually
740 * (i.e. if you did not call dbus_bus_register()). Can only be called
741 * once per connection. After the unique name is set, you can get it
742 * with dbus_bus_get_unique_name().
744 * The only reason to use this function is to re-implement the
745 * equivalent of dbus_bus_register() yourself. One (probably unusual)
746 * reason to do that might be to do the bus registration call
747 * asynchronously instead of synchronously.
749 * @note Just use dbus_bus_get() or dbus_bus_get_private(), or worst
750 * case dbus_bus_register(), instead of messing with this
751 * function. There's really no point creating pain for yourself by
752 * doing things manually.
754 * It's hard to use this function safely on shared connections
755 * (created by dbus_connection_open()) in a multithreaded application,
756 * because only one registration attempt can be sent to the bus. If
757 * two threads are both sending the registration message, there is no
758 * mechanism in libdbus itself to avoid sending it twice.
760 * Thus, you need a way to coordinate which thread sends the
761 * registration attempt; which also means you know which thread
762 * will call dbus_bus_set_unique_name(). If you don't know
763 * about all threads in the app (for example, if some libraries
764 * you're using might start libdbus-using threads), then you
765 * need to avoid using this function on shared connections.
767 * @param connection the connection
768 * @param unique_name the unique name
769 * @returns #FALSE if not enough memory
772 dbus_bus_set_unique_name (DBusConnection *connection,
773 const char *unique_name)
776 dbus_bool_t success = FALSE;
778 _dbus_return_val_if_fail (connection != NULL, FALSE);
779 _dbus_return_val_if_fail (unique_name != NULL, FALSE);
781 if (!_DBUS_LOCK (bus_datas))
783 /* do not "goto out", that would try to unlock */
787 bd = ensure_bus_data (connection);
791 _dbus_assert (bd->unique_name == NULL);
793 bd->unique_name = _dbus_strdup (unique_name);
794 success = bd->unique_name != NULL;
797 _DBUS_UNLOCK (bus_datas);
803 * Gets the unique name of the connection as assigned by the message
804 * bus. Only possible after the connection has been registered with
805 * the message bus. All connections returned by dbus_bus_get() or
806 * dbus_bus_get_private() have been successfully registered.
808 * The name remains valid until the connection is freed, and
809 * should not be freed by the caller.
811 * Other than dbus_bus_get(), there are two ways to set the unique
812 * name; one is dbus_bus_register(), the other is
813 * dbus_bus_set_unique_name(). You are responsible for calling
814 * dbus_bus_set_unique_name() if you register by hand instead of using
815 * dbus_bus_register().
817 * @param connection the connection
818 * @returns the unique name or #NULL on error
821 dbus_bus_get_unique_name (DBusConnection *connection)
824 const char *unique_name = NULL;
826 _dbus_return_val_if_fail (connection != NULL, NULL);
828 if (!_DBUS_LOCK (bus_datas))
830 /* We'd have initialized locks when we gave it its unique name, if it
831 * had one. Don't "goto out", that would try to unlock. */
835 bd = ensure_bus_data (connection);
839 unique_name = bd->unique_name;
842 _DBUS_UNLOCK (bus_datas);
848 * Asks the bus to return the UID the named connection authenticated
849 * as, if any. Only works on UNIX; only works for connections on the
850 * same machine as the bus. If you are not on the same machine as the
851 * bus, then calling this is probably a bad idea, since the UID will
852 * mean little to your application.
854 * For the system message bus you're guaranteed to be on the same
855 * machine since it only listens on a UNIX domain socket (at least,
856 * as shipped by default).
858 * This function only works for connections that authenticated as
859 * a UNIX user, right now that includes all bus connections, but
860 * it's very possible to have connections with no associated UID.
861 * So check for errors and do something sensible if they happen.
863 * This function will always return an error on Windows.
865 * @param connection the connection
866 * @param name a name owned by the connection
867 * @param error location to store the error
868 * @returns the unix user id, or ((unsigned)-1) if error is set
871 dbus_bus_get_unix_user (DBusConnection *connection,
875 DBusMessage *message, *reply;
878 _dbus_return_val_if_fail (connection != NULL, DBUS_UID_UNSET);
879 _dbus_return_val_if_fail (name != NULL, DBUS_UID_UNSET);
880 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), DBUS_UID_UNSET);
881 _dbus_return_val_if_error_is_set (error, DBUS_UID_UNSET);
883 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
886 "GetConnectionUnixUser");
890 _DBUS_SET_OOM (error);
891 return DBUS_UID_UNSET;
894 if (!dbus_message_append_args (message,
895 DBUS_TYPE_STRING, &name,
898 dbus_message_unref (message);
899 _DBUS_SET_OOM (error);
900 return DBUS_UID_UNSET;
903 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
906 dbus_message_unref (message);
910 _DBUS_ASSERT_ERROR_IS_SET (error);
911 return DBUS_UID_UNSET;
914 if (dbus_set_error_from_message (error, reply))
916 _DBUS_ASSERT_ERROR_IS_SET (error);
917 dbus_message_unref (reply);
918 return DBUS_UID_UNSET;
921 if (!dbus_message_get_args (reply, error,
922 DBUS_TYPE_UINT32, &uid,
925 _DBUS_ASSERT_ERROR_IS_SET (error);
926 dbus_message_unref (reply);
927 return DBUS_UID_UNSET;
930 dbus_message_unref (reply);
932 return (unsigned long) uid;
936 * Asks the bus to return its globally unique ID, as described in the
937 * D-Bus specification. For the session bus, this is useful as a way
938 * to uniquely identify each user session. For the system bus,
939 * probably the bus ID is not useful; instead, use the machine ID
940 * since it's accessible without necessarily connecting to the bus and
941 * may be persistent beyond a single bus instance (across reboots for
942 * example). See dbus_get_local_machine_id().
944 * In addition to an ID for each bus and an ID for each machine, there is
945 * an ID for each address that the bus is listening on; that can
946 * be retrieved with dbus_connection_get_server_id(), though it is
947 * probably not very useful.
949 * @param connection the connection
950 * @param error location to store the error
951 * @returns the bus ID or #NULL if error is set
954 dbus_bus_get_id (DBusConnection *connection,
957 DBusMessage *message, *reply;
959 const char *v_STRING;
961 _dbus_return_val_if_fail (connection != NULL, NULL);
962 _dbus_return_val_if_error_is_set (error, NULL);
964 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
971 _DBUS_SET_OOM (error);
975 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
978 dbus_message_unref (message);
982 _DBUS_ASSERT_ERROR_IS_SET (error);
986 if (dbus_set_error_from_message (error, reply))
988 _DBUS_ASSERT_ERROR_IS_SET (error);
989 dbus_message_unref (reply);
994 if (!dbus_message_get_args (reply, error,
995 DBUS_TYPE_STRING, &v_STRING,
998 _DBUS_ASSERT_ERROR_IS_SET (error);
999 dbus_message_unref (reply);
1003 id = _dbus_strdup (v_STRING); /* may be NULL */
1005 dbus_message_unref (reply);
1008 _DBUS_SET_OOM (error);
1010 /* FIXME it might be nice to cache the ID locally */
1016 * Asks the bus to assign the given name to this connection by invoking
1017 * the RequestName method on the bus. This method is fully documented
1018 * in the D-Bus specification. For quick reference, the flags and
1019 * result codes are discussed here, but the specification is the
1020 * canonical version of this information.
1022 * First you should know that for each bus name, the bus stores
1023 * a queue of connections that would like to own it. Only
1024 * one owns it at a time - called the primary owner. If the primary
1025 * owner releases the name or disconnects, then the next owner in the
1026 * queue atomically takes over.
1028 * So for example if you have an application org.freedesktop.TextEditor
1029 * and multiple instances of it can be run, you can have all of them
1030 * sitting in the queue. The first one to start up will receive messages
1031 * sent to org.freedesktop.TextEditor, but if that one exits another
1032 * will become the primary owner and receive messages.
1034 * The queue means you don't need to manually watch for the current owner to
1035 * disappear and then request the name again.
1037 * When requesting a name, you can specify several flags.
1039 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT and #DBUS_NAME_FLAG_DO_NOT_QUEUE
1040 * are properties stored by the bus for this connection with respect to
1041 * each requested bus name. These properties are stored even if the
1042 * connection is queued and does not become the primary owner.
1043 * You can update these flags by calling RequestName again (even if
1044 * you already own the name).
1046 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT means that another requestor of the
1047 * name can take it away from you by specifying #DBUS_NAME_FLAG_REPLACE_EXISTING.
1049 * #DBUS_NAME_FLAG_DO_NOT_QUEUE means that if you aren't the primary owner,
1050 * you don't want to be queued up - you only care about being the
1053 * Unlike the other two flags, #DBUS_NAME_FLAG_REPLACE_EXISTING is a property
1054 * of the individual RequestName call, i.e. the bus does not persistently
1055 * associate it with the connection-name pair. If a RequestName call includes
1056 * the #DBUS_NAME_FLAG_REPLACE_EXISTING flag, and the current primary
1057 * owner has #DBUS_NAME_FLAG_ALLOW_REPLACEMENT set, then the current primary
1058 * owner will be kicked off.
1060 * If no flags are given, an application will receive the requested
1061 * name only if the name is currently unowned; and it will NOT give
1062 * up the name if another application asks to take it over using
1063 * #DBUS_NAME_FLAG_REPLACE_EXISTING.
1065 * This function returns a result code. The possible result codes
1068 * #DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER means that the name had no
1069 * existing owner, and the caller is now the primary owner; or that
1070 * the name had an owner, and the caller specified
1071 * #DBUS_NAME_FLAG_REPLACE_EXISTING, and the current owner
1072 * specified #DBUS_NAME_FLAG_ALLOW_REPLACEMENT.
1074 * #DBUS_REQUEST_NAME_REPLY_IN_QUEUE happens only if the caller does NOT
1075 * specify #DBUS_NAME_FLAG_DO_NOT_QUEUE and either the current owner
1076 * did NOT specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT
1077 * specify #DBUS_NAME_FLAG_REPLACE_EXISTING. In this case the caller ends up
1078 * in a queue to own the name after the current owner gives it up.
1080 * #DBUS_REQUEST_NAME_REPLY_EXISTS happens if the name has an owner
1081 * already and the caller specifies #DBUS_NAME_FLAG_DO_NOT_QUEUE
1082 * and either the current owner has NOT specified
1083 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT specify
1084 * #DBUS_NAME_FLAG_REPLACE_EXISTING.
1086 * #DBUS_REQUEST_NAME_REPLY_ALREADY_OWNER happens if an application
1087 * requests a name it already owns. (Re-requesting a name is useful if
1088 * you want to change the #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or
1089 * #DBUS_NAME_FLAG_DO_NOT_QUEUE settings.)
1091 * When a service represents an application, say "text editor," then
1092 * it should specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT if it wants
1093 * the last editor started to be the user's editor vs. the first one
1094 * started. Then any editor that can be the user's editor should
1095 * specify #DBUS_NAME_FLAG_REPLACE_EXISTING to either take over
1096 * (last-started-wins) or be queued up (first-started-wins) according
1097 * to whether #DBUS_NAME_FLAG_ALLOW_REPLACEMENT was given.
1099 * Conventionally, single-instance applications often offer a command
1100 * line option called --replace which means to replace the current
1101 * instance. To implement this, always set
1102 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT when you request your
1103 * application's bus name. When you lose ownership of your bus name,
1104 * you need to exit. Look for the signal "NameLost" from
1105 * #DBUS_SERVICE_DBUS and #DBUS_INTERFACE_DBUS (the signal's first
1106 * argument is the bus name that was lost). If starting up without
1107 * --replace, do not specify #DBUS_NAME_FLAG_REPLACE_EXISTING, and
1108 * exit if you fail to become the bus name owner. If --replace is
1109 * given, ask to replace the old owner.
1111 * @param connection the connection
1112 * @param name the name to request
1113 * @param flags flags
1114 * @param error location to store the error
1115 * @returns a result code, -1 if error is set
1118 dbus_bus_request_name (DBusConnection *connection,
1123 DBusMessage *message, *reply;
1124 dbus_uint32_t result;
1126 _dbus_return_val_if_fail (connection != NULL, 0);
1127 _dbus_return_val_if_fail (name != NULL, 0);
1128 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0);
1129 _dbus_return_val_if_error_is_set (error, 0);
1131 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1133 DBUS_INTERFACE_DBUS,
1136 if (message == NULL)
1138 _DBUS_SET_OOM (error);
1142 if (!dbus_message_append_args (message,
1143 DBUS_TYPE_STRING, &name,
1144 DBUS_TYPE_UINT32, &flags,
1147 dbus_message_unref (message);
1148 _DBUS_SET_OOM (error);
1152 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
1155 dbus_message_unref (message);
1159 _DBUS_ASSERT_ERROR_IS_SET (error);
1163 if (dbus_set_error_from_message (error, reply))
1165 _DBUS_ASSERT_ERROR_IS_SET (error);
1166 dbus_message_unref (reply);
1170 if (!dbus_message_get_args (reply, error,
1171 DBUS_TYPE_UINT32, &result,
1174 _DBUS_ASSERT_ERROR_IS_SET (error);
1175 dbus_message_unref (reply);
1179 dbus_message_unref (reply);
1186 * Asks the bus to unassign the given name from this connection by
1187 * invoking the ReleaseName method on the bus. The "ReleaseName"
1188 * method is canonically documented in the D-Bus specification.
1190 * Possible results are: #DBUS_RELEASE_NAME_REPLY_RELEASED
1191 * which means you owned the name or were in the queue to own it,
1192 * and and now you don't own it and aren't in the queue.
1193 * #DBUS_RELEASE_NAME_REPLY_NOT_OWNER which means someone else
1194 * owns the name so you can't release it.
1195 * #DBUS_RELEASE_NAME_REPLY_NON_EXISTENT
1196 * which means nobody owned the name.
1198 * @param connection the connection
1199 * @param name the name to remove
1200 * @param error location to store the error
1201 * @returns a result code, -1 if error is set
1204 dbus_bus_release_name (DBusConnection *connection,
1208 DBusMessage *message, *reply;
1209 dbus_uint32_t result;
1211 _dbus_return_val_if_fail (connection != NULL, 0);
1212 _dbus_return_val_if_fail (name != NULL, 0);
1213 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0);
1214 _dbus_return_val_if_error_is_set (error, 0);
1216 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1218 DBUS_INTERFACE_DBUS,
1221 if (message == NULL)
1223 _DBUS_SET_OOM (error);
1227 if (!dbus_message_append_args (message,
1228 DBUS_TYPE_STRING, &name,
1231 dbus_message_unref (message);
1232 _DBUS_SET_OOM (error);
1236 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
1239 dbus_message_unref (message);
1243 _DBUS_ASSERT_ERROR_IS_SET (error);
1247 if (dbus_set_error_from_message (error, reply))
1249 _DBUS_ASSERT_ERROR_IS_SET (error);
1250 dbus_message_unref (reply);
1254 if (!dbus_message_get_args (reply, error,
1255 DBUS_TYPE_UINT32, &result,
1258 _DBUS_ASSERT_ERROR_IS_SET (error);
1259 dbus_message_unref (reply);
1263 dbus_message_unref (reply);
1269 * Asks the bus whether a certain name has an owner.
1271 * Using this can easily result in a race condition,
1272 * since an owner can appear or disappear after you
1275 * If you want to request a name, just request it;
1276 * if you want to avoid replacing a current owner,
1277 * don't specify #DBUS_NAME_FLAG_REPLACE_EXISTING and
1278 * you will get an error if there's already an owner.
1280 * @param connection the connection
1281 * @param name the name
1282 * @param error location to store any errors
1283 * @returns #TRUE if the name exists, #FALSE if not or on error
1286 dbus_bus_name_has_owner (DBusConnection *connection,
1290 DBusMessage *message, *reply;
1293 _dbus_return_val_if_fail (connection != NULL, FALSE);
1294 _dbus_return_val_if_fail (name != NULL, FALSE);
1295 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE);
1296 _dbus_return_val_if_error_is_set (error, FALSE);
1298 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1300 DBUS_INTERFACE_DBUS,
1302 if (message == NULL)
1304 _DBUS_SET_OOM (error);
1308 if (!dbus_message_append_args (message,
1309 DBUS_TYPE_STRING, &name,
1312 dbus_message_unref (message);
1313 _DBUS_SET_OOM (error);
1317 reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
1318 dbus_message_unref (message);
1322 _DBUS_ASSERT_ERROR_IS_SET (error);
1326 if (!dbus_message_get_args (reply, error,
1327 DBUS_TYPE_BOOLEAN, &exists,
1330 _DBUS_ASSERT_ERROR_IS_SET (error);
1331 dbus_message_unref (reply);
1335 dbus_message_unref (reply);
1340 * Starts a service that will request ownership of the given name.
1341 * The returned result will be one of be one of
1342 * #DBUS_START_REPLY_SUCCESS or #DBUS_START_REPLY_ALREADY_RUNNING if
1343 * successful. Pass #NULL if you don't care about the result.
1345 * The flags parameter is for future expansion, currently you should
1348 * It's often easier to avoid explicitly starting services, and
1349 * just send a method call to the service's bus name instead.
1350 * Method calls start a service to handle them by default
1351 * unless you call dbus_message_set_auto_start() to disable this
1354 * @param connection the connection
1355 * @param name the name we want the new service to request
1356 * @param flags the flags (should always be 0 for now)
1357 * @param result a place to store the result or #NULL
1358 * @param error location to store any errors
1359 * @returns #TRUE if the activation succeeded, #FALSE if not
1362 dbus_bus_start_service_by_name (DBusConnection *connection,
1364 dbus_uint32_t flags,
1365 dbus_uint32_t *result,
1371 _dbus_return_val_if_fail (connection != NULL, FALSE);
1372 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE);
1374 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1376 DBUS_INTERFACE_DBUS,
1377 "StartServiceByName");
1379 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &name,
1380 DBUS_TYPE_UINT32, &flags, DBUS_TYPE_INVALID))
1382 dbus_message_unref (msg);
1383 _DBUS_SET_OOM (error);
1387 reply = dbus_connection_send_with_reply_and_block (connection, msg,
1389 dbus_message_unref (msg);
1393 _DBUS_ASSERT_ERROR_IS_SET (error);
1397 if (dbus_set_error_from_message (error, reply))
1399 _DBUS_ASSERT_ERROR_IS_SET (error);
1400 dbus_message_unref (reply);
1404 if (result != NULL &&
1405 !dbus_message_get_args (reply, error, DBUS_TYPE_UINT32,
1406 result, DBUS_TYPE_INVALID))
1408 _DBUS_ASSERT_ERROR_IS_SET (error);
1409 dbus_message_unref (reply);
1413 dbus_message_unref (reply);
1418 send_no_return_values (DBusConnection *connection,
1424 /* Block to check success codepath */
1427 reply = dbus_connection_send_with_reply_and_block (connection, msg,
1431 _DBUS_ASSERT_ERROR_IS_SET (error);
1433 dbus_message_unref (reply);
1437 /* Silently-fail nonblocking codepath */
1438 dbus_message_set_no_reply (msg, TRUE);
1439 dbus_connection_send (connection, msg, NULL);
1444 * Adds a match rule to match messages going through the message bus.
1445 * The "rule" argument is the string form of a match rule.
1447 * If you pass #NULL for the error, this function will not
1448 * block; the match thus won't be added until you flush the
1449 * connection, and if there's an error adding the match
1450 * you won't find out about it. This is generally acceptable, since the
1451 * possible errors (including a lack of resources in the bus, the connection
1452 * having exceeded its quota of active match rules, or the match rule being
1453 * unparseable) are generally unrecoverable.
1455 * If you pass non-#NULL for the error this function will
1456 * block until it gets a reply. This may be useful when using match rule keys
1457 * introduced in recent versions of D-Bus, like 'arg0namespace', to allow the
1458 * application to fall back to less efficient match rules supported by older
1459 * versions of the daemon if the running version is not new enough; or when
1460 * using user-supplied rules rather than rules hard-coded at compile time.
1462 * Normal API conventions would have the function return
1463 * a boolean value indicating whether the error was set,
1464 * but that would require blocking always to determine
1467 * The AddMatch method is fully documented in the D-Bus
1468 * specification. For quick reference, the format of the
1469 * match rules is discussed here, but the specification
1470 * is the canonical version of this information.
1472 * Rules are specified as a string of comma separated
1473 * key/value pairs. An example is
1474 * "type='signal',sender='org.freedesktop.DBus',
1475 * interface='org.freedesktop.DBus',member='Foo',
1476 * path='/bar/foo',destination=':452345.34'"
1478 * Possible keys you can match on are type, sender,
1479 * interface, member, path, destination and numbered
1480 * keys to match message args (keys are 'arg0', 'arg1', etc.).
1481 * Omitting a key from the rule indicates
1482 * a wildcard match. For instance omitting
1483 * the member from a match rule but adding a sender would
1484 * let all messages from that sender through regardless of
1487 * Matches are inclusive not exclusive so as long as one
1488 * rule matches the message will get through. It is important
1489 * to note this because every time a message is received the
1490 * application will be paged into memory to process it. This
1491 * can cause performance problems such as draining batteries
1492 * on embedded platforms.
1494 * If you match message args ('arg0', 'arg1', and so forth)
1495 * only string arguments will match. That is, arg0='5' means
1496 * match the string "5" not the integer 5.
1498 * Currently there is no way to match against non-string arguments.
1500 * A specialised form of wildcard matching on arguments is
1501 * supported for path-like namespaces. If your argument match has
1502 * a 'path' suffix (eg: "arg0path='/some/path/'") then it is
1503 * considered a match if the argument exactly matches the given
1504 * string or if one of them ends in a '/' and is a prefix of the
1507 * Matching on interface is tricky because method call
1508 * messages only optionally specify the interface.
1509 * If a message omits the interface, then it will NOT match
1510 * if the rule specifies an interface name. This means match
1511 * rules on method calls should not usually give an interface.
1513 * However, signal messages are required to include the interface
1514 * so when matching signals usually you should specify the interface
1515 * in the match rule.
1517 * For security reasons, you can match arguments only up to
1518 * #DBUS_MAXIMUM_MATCH_RULE_ARG_NUMBER.
1520 * Match rules have a maximum length of #DBUS_MAXIMUM_MATCH_RULE_LENGTH
1523 * Both of these maximums are much higher than you're likely to need,
1524 * they only exist because the D-Bus bus daemon has fixed limits on
1525 * all resource usage.
1527 * @param connection connection to the message bus
1528 * @param rule textual form of match rule
1529 * @param error location to store any errors
1532 dbus_bus_add_match (DBusConnection *connection,
1538 _dbus_return_if_fail (rule != NULL);
1540 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1542 DBUS_INTERFACE_DBUS,
1547 _DBUS_SET_OOM (error);
1551 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &rule,
1554 dbus_message_unref (msg);
1555 _DBUS_SET_OOM (error);
1559 send_no_return_values (connection, msg, error);
1561 dbus_message_unref (msg);
1565 * Removes a previously-added match rule "by value" (the most
1566 * recently-added identical rule gets removed). The "rule" argument
1567 * is the string form of a match rule.
1569 * The bus compares match rules semantically, not textually, so
1570 * whitespace and ordering don't have to be identical to
1571 * the rule you passed to dbus_bus_add_match().
1573 * If you pass #NULL for the error, this function will not
1574 * block; otherwise it will. See detailed explanation in
1575 * docs for dbus_bus_add_match().
1577 * @param connection connection to the message bus
1578 * @param rule textual form of match rule
1579 * @param error location to store any errors
1582 dbus_bus_remove_match (DBusConnection *connection,
1588 _dbus_return_if_fail (rule != NULL);
1590 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1592 DBUS_INTERFACE_DBUS,
1595 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &rule,
1598 dbus_message_unref (msg);
1599 _DBUS_SET_OOM (error);
1603 send_no_return_values (connection, msg, error);
1605 dbus_message_unref (msg);