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;
143 init_session_address (void)
149 /* First, look in the environment. This is the normal case on
150 * freedesktop.org/Unix systems. */
151 get_from_env (&bus_connection_addresses[DBUS_BUS_SESSION],
152 "DBUS_SESSION_BUS_ADDRESS");
153 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
155 dbus_bool_t supported;
157 DBusError error = DBUS_ERROR_INIT;
159 if (!_dbus_string_init (&addr))
163 /* So it's not in the environment - let's try a platform-specific method.
164 * On MacOS, this involves asking launchd. On Windows (not specified yet)
165 * we might do a COM lookup.
166 * Ignore errors - if we failed, fall back to autolaunch. */
167 retval = _dbus_lookup_session_address (&supported, &addr, &error);
168 if (supported && retval)
170 retval =_dbus_string_steal_data (&addr, &bus_connection_addresses[DBUS_BUS_SESSION]);
172 else if (supported && !retval)
174 if (dbus_error_is_set(&error))
175 _dbus_warn ("Dynamic session lookup supported but failed: %s\n", error.message);
177 _dbus_warn ("Dynamic session lookup supported but failed silently\n");
179 _dbus_string_free (&addr);
187 /* We have a hard-coded (but compile-time-configurable) fallback address for
188 * the session bus. */
189 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
190 bus_connection_addresses[DBUS_BUS_SESSION] =
191 _dbus_strdup (DBUS_SESSION_BUS_CONNECT_ADDRESS);
193 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
200 init_connections_unlocked (void)
208 while (i < N_BUS_TYPES)
210 bus_connections[i] = NULL;
214 /* Don't init these twice, we may run this code twice if
215 * init_connections_unlocked() fails midway through.
216 * In practice, each block below should contain only one
217 * "return FALSE" or running through twice may not
221 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
223 _dbus_verbose ("Filling in system bus address...\n");
225 if (!get_from_env (&bus_connection_addresses[DBUS_BUS_SYSTEM],
226 "DBUS_SYSTEM_BUS_ADDRESS"))
231 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
233 /* Use default system bus address if none set in environment */
234 bus_connection_addresses[DBUS_BUS_SYSTEM] =
235 _dbus_strdup (DBUS_SYSTEM_BUS_DEFAULT_ADDRESS);
237 if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
240 _dbus_verbose (" used default system bus \"%s\"\n",
241 bus_connection_addresses[DBUS_BUS_SYSTEM]);
244 _dbus_verbose (" used env var system bus \"%s\"\n",
245 bus_connection_addresses[DBUS_BUS_SYSTEM]);
247 if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
249 _dbus_verbose ("Filling in session bus address...\n");
251 if (!init_session_address ())
254 _dbus_verbose (" \"%s\"\n", bus_connection_addresses[DBUS_BUS_SESSION] ?
255 bus_connection_addresses[DBUS_BUS_SESSION] : "none set");
258 if (bus_connection_addresses[DBUS_BUS_STARTER] == NULL)
260 _dbus_verbose ("Filling in activation bus address...\n");
262 if (!get_from_env (&bus_connection_addresses[DBUS_BUS_STARTER],
263 "DBUS_STARTER_ADDRESS"))
266 _dbus_verbose (" \"%s\"\n", bus_connection_addresses[DBUS_BUS_STARTER] ?
267 bus_connection_addresses[DBUS_BUS_STARTER] : "none set");
271 if (bus_connection_addresses[DBUS_BUS_STARTER] != NULL)
273 s = _dbus_getenv ("DBUS_STARTER_BUS_TYPE");
277 _dbus_verbose ("Bus activation type was set to \"%s\"\n", s);
279 if (strcmp (s, "system") == 0)
280 activation_bus_type = DBUS_BUS_SYSTEM;
281 else if (strcmp (s, "session") == 0)
282 activation_bus_type = DBUS_BUS_SESSION;
287 /* Default to the session bus instead if available */
288 if (bus_connection_addresses[DBUS_BUS_SESSION] != NULL)
290 bus_connection_addresses[DBUS_BUS_STARTER] =
291 _dbus_strdup (bus_connection_addresses[DBUS_BUS_SESSION]);
292 if (bus_connection_addresses[DBUS_BUS_STARTER] == NULL)
297 /* If we return FALSE we have to be sure that restarting
298 * the above code will work right
301 if (!dbus_setenv ("DBUS_ACTIVATION_ADDRESS", NULL))
304 if (!dbus_setenv ("DBUS_ACTIVATION_BUS_TYPE", NULL))
307 if (!_dbus_register_shutdown_func (addresses_shutdown_func,
318 bus_data_free (void *data)
322 if (bd->is_well_known)
326 if (!_DBUS_LOCK (bus))
327 _dbus_assert_not_reached ("global locks should have been initialized "
328 "when we attached bus data");
330 /* We may be stored in more than one slot */
331 /* This should now be impossible - these slots are supposed to
332 * be cleared on disconnect, so should not need to be cleared on
336 while (i < N_BUS_TYPES)
338 if (bus_connections[i] == bd->connection)
339 bus_connections[i] = NULL;
346 dbus_free (bd->unique_name);
349 dbus_connection_free_data_slot (&bus_data_slot);
353 ensure_bus_data (DBusConnection *connection)
357 if (!dbus_connection_allocate_data_slot (&bus_data_slot))
360 bd = dbus_connection_get_data (connection, bus_data_slot);
363 bd = dbus_new0 (BusData, 1);
366 dbus_connection_free_data_slot (&bus_data_slot);
370 bd->connection = connection;
372 if (!dbus_connection_set_data (connection, bus_data_slot, bd,
376 dbus_connection_free_data_slot (&bus_data_slot);
380 /* Data slot refcount now held by the BusData */
384 dbus_connection_free_data_slot (&bus_data_slot);
391 * Internal function that checks to see if this
392 * is a shared connection owned by the bus and if it is unref it.
394 * @param connection a connection that has been disconnected.
397 _dbus_bus_notify_shared_connection_disconnected_unlocked (DBusConnection *connection)
401 if (!_DBUS_LOCK (bus))
403 /* If it was in bus_connections, we would have initialized global locks
404 * when we added it. So, it can't be. */
408 /* We are expecting to have the connection saved in only one of these
409 * slots, but someone could in a pathological case set system and session
410 * bus to the same bus or something. Or set one of them to the starter
411 * bus without setting the starter bus type in the env variable.
412 * So we don't break the loop as soon as we find a match.
414 for (i = 0; i < N_BUS_TYPES; ++i)
416 if (bus_connections[i] == connection)
418 bus_connections[i] = NULL;
425 static DBusConnection *
426 internal_bus_get (DBusBusType type,
431 DBusConnection *connection;
433 DBusBusType address_type;
435 _dbus_return_val_if_fail (type >= 0 && type < N_BUS_TYPES, NULL);
436 _dbus_return_val_if_error_is_set (error, NULL);
440 if (!_DBUS_LOCK (bus))
442 _DBUS_SET_OOM (error);
443 /* do not "goto out", that would try to unlock */
447 if (!init_connections_unlocked ())
449 _DBUS_SET_OOM (error);
453 /* We want to use the activation address even if the
454 * activating bus is the session or system bus,
459 /* Use the real type of the activation bus for getting its
460 * connection, but only if the real type's address is available. (If
461 * the activating bus isn't a well-known bus then
462 * activation_bus_type == DBUS_BUS_STARTER)
464 if (type == DBUS_BUS_STARTER &&
465 bus_connection_addresses[activation_bus_type] != NULL)
466 type = activation_bus_type;
468 if (!private && bus_connections[type] != NULL)
470 connection = bus_connections[type];
471 dbus_connection_ref (connection);
475 address = bus_connection_addresses[address_type];
478 dbus_set_error (error, DBUS_ERROR_FAILED,
479 "Unable to determine the address of the message bus (try 'man dbus-launch' and 'man dbus-daemon' for help)");
484 connection = dbus_connection_open_private (address, error);
486 connection = dbus_connection_open (address, error);
493 _dbus_verbose (" !!! dbus_connection_open finished successfully !!!! \n"); //todo RP to be removed
495 if (!dbus_bus_register (connection, error))
497 _dbus_connection_close_possibly_shared (connection);
498 dbus_connection_unref (connection);
505 /* store a weak ref to the connection (dbus-connection.c is
506 * supposed to have a strong ref that it drops on disconnect,
507 * since this is a shared connection)
509 bus_connections[type] = connection;
512 /* By default we're bound to the lifecycle of
515 dbus_connection_set_exit_on_disconnect (connection,
518 if (!_DBUS_LOCK (bus_datas))
519 _dbus_assert_not_reached ("global locks were initialized already");
521 bd = ensure_bus_data (connection);
522 _dbus_assert (bd != NULL); /* it should have been created on
523 register, so OOM not possible */
524 bd->is_well_known = TRUE;
525 _DBUS_UNLOCK (bus_datas);
528 /* Return a reference to the caller, or NULL with error set. */
529 if (connection == NULL)
530 _DBUS_ASSERT_ERROR_IS_SET (error);
537 /** @} */ /* end of implementation details docs */
540 * @addtogroup DBusBus
545 * Connects to a bus daemon and registers the client with it. If a
546 * connection to the bus already exists, then that connection is
547 * returned. The caller of this function owns a reference to the bus.
549 * The caller may NOT call dbus_connection_close() on this connection;
550 * see dbus_connection_open() and dbus_connection_close() for details
553 * If this function obtains a new connection object never before
554 * returned from dbus_bus_get(), it will call
555 * dbus_connection_set_exit_on_disconnect(), so the application
556 * will exit if the connection closes. You can undo this
557 * by calling dbus_connection_set_exit_on_disconnect() yourself
558 * after you get the connection.
560 * dbus_bus_get() calls dbus_bus_register() for you.
562 * If returning a newly-created connection, this function will block
563 * until authentication and bus registration are complete.
565 * @param type bus type
566 * @param error address where an error can be returned.
567 * @returns a #DBusConnection with new ref or #NULL on error
570 dbus_bus_get (DBusBusType type,
573 return internal_bus_get (type, FALSE, error);
577 * Connects to a bus daemon and registers the client with it as with
578 * dbus_bus_register(). Unlike dbus_bus_get(), always creates a new
579 * connection. This connection will not be saved or recycled by
580 * libdbus. Caller owns a reference to the bus and must either close
581 * it or know it to be closed prior to releasing this reference.
583 * See dbus_connection_open_private() for more details on when to
584 * close and unref this connection.
586 * This function calls
587 * dbus_connection_set_exit_on_disconnect() on the new connection, so the application
588 * will exit if the connection closes. You can undo this
589 * by calling dbus_connection_set_exit_on_disconnect() yourself
590 * after you get the connection.
592 * dbus_bus_get_private() calls dbus_bus_register() for you.
594 * This function will block until authentication and bus registration
597 * @param type bus type
598 * @param error address where an error can be returned.
599 * @returns a DBusConnection with new ref
602 dbus_bus_get_private (DBusBusType type,
605 return internal_bus_get (type, TRUE, error);
609 * Registers a connection with the bus. This must be the first
610 * thing an application does when connecting to the message bus.
611 * If registration succeeds, the unique name will be set,
612 * and can be obtained using dbus_bus_get_unique_name().
614 * This function will block until registration is complete.
616 * If the connection has already registered with the bus
617 * (determined by checking whether dbus_bus_get_unique_name()
618 * returns a non-#NULL value), then this function does nothing.
620 * If you use dbus_bus_get() or dbus_bus_get_private() this
621 * function will be called for you.
623 * @note Just use dbus_bus_get() or dbus_bus_get_private() instead of
624 * dbus_bus_register() and save yourself some pain. Using
625 * dbus_bus_register() manually is only useful if you have your
626 * own custom message bus not found in #DBusBusType.
628 * If you open a bus connection with dbus_connection_open() or
629 * dbus_connection_open_private() you will have to dbus_bus_register()
630 * yourself, or make the appropriate registration method calls
631 * yourself. If you send the method calls yourself, call
632 * dbus_bus_set_unique_name() with the unique bus name you get from
635 * For shared connections (created with dbus_connection_open()) in a
636 * multithreaded application, you can't really make the registration
637 * calls yourself, because you don't know whether some other thread is
638 * also registering, and the bus will kick you off if you send two
639 * registration messages.
641 * If you use dbus_bus_register() however, there is a lock that
642 * keeps both apps from registering at the same time.
644 * The rule in a multithreaded app, then, is that dbus_bus_register()
645 * must be used to register, or you need to have your own locks that
646 * all threads in the app will respect.
648 * In a single-threaded application you can register by hand instead
649 * of using dbus_bus_register(), as long as you check
650 * dbus_bus_get_unique_name() to see if a unique name has already been
651 * stored by another thread before you send the registration messages.
653 * @param connection the connection
654 * @param error place to store errors
655 * @returns #TRUE on success
658 dbus_bus_register (DBusConnection *connection,
661 DBusMessage *message, *reply;
667 _dbus_return_val_if_fail (connection != NULL, FALSE);
668 _dbus_return_val_if_error_is_set (error, FALSE);
674 if (!_DBUS_LOCK (bus_datas))
676 _DBUS_SET_OOM (error);
677 /* do not "goto out", that would try to unlock */
681 bd = ensure_bus_data (connection);
684 _DBUS_SET_OOM (error);
688 if (bd->unique_name != NULL)
690 _dbus_verbose ("Ignoring attempt to register the same DBusConnection %s with the message bus a second time.\n",
696 if(dbus_transport_is_kdbus(connection))
698 name = malloc(snprintf(name, 0, "%llu", ULLONG_MAX) + 1);
699 if(!bus_register_kdbus(name, connection, error))
702 if(!bus_register_policy_kdbus(name, connection, error))
705 dbus_connection_set_is_authenticated(connection);
709 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
715 _DBUS_SET_OOM (error);
719 reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
723 else if (dbus_set_error_from_message (error, reply))
725 else if (!dbus_message_get_args (reply, error,
726 DBUS_TYPE_STRING, &name,
731 bd->unique_name = _dbus_strdup (name);
733 /* determine sender once, not for every message */
734 sender = malloc (strlen(name) + 4);
737 strcpy(sender,":1.");
738 strcpy(&sender[3], name);
739 _dbus_verbose ("Message sender: %s\n", sender);
740 dbus_connection_set_sender(connection, sender);
743 if (bd->unique_name == NULL)
745 _DBUS_SET_OOM (error);
748 //_dbus_verbose("-- Our uniqe name is: %s\n", bd->unique_name);
752 _DBUS_UNLOCK (bus_datas);
755 dbus_message_unref (message);
760 dbus_message_unref (reply);
763 _DBUS_ASSERT_ERROR_IS_SET (error);
770 * Sets the unique name of the connection, as assigned by the message
771 * bus. Can only be used if you registered with the bus manually
772 * (i.e. if you did not call dbus_bus_register()). Can only be called
773 * once per connection. After the unique name is set, you can get it
774 * with dbus_bus_get_unique_name().
776 * The only reason to use this function is to re-implement the
777 * equivalent of dbus_bus_register() yourself. One (probably unusual)
778 * reason to do that might be to do the bus registration call
779 * asynchronously instead of synchronously.
781 * @note Just use dbus_bus_get() or dbus_bus_get_private(), or worst
782 * case dbus_bus_register(), instead of messing with this
783 * function. There's really no point creating pain for yourself by
784 * doing things manually.
786 * It's hard to use this function safely on shared connections
787 * (created by dbus_connection_open()) in a multithreaded application,
788 * because only one registration attempt can be sent to the bus. If
789 * two threads are both sending the registration message, there is no
790 * mechanism in libdbus itself to avoid sending it twice.
792 * Thus, you need a way to coordinate which thread sends the
793 * registration attempt; which also means you know which thread
794 * will call dbus_bus_set_unique_name(). If you don't know
795 * about all threads in the app (for example, if some libraries
796 * you're using might start libdbus-using threads), then you
797 * need to avoid using this function on shared connections.
799 * @param connection the connection
800 * @param unique_name the unique name
801 * @returns #FALSE if not enough memory
804 dbus_bus_set_unique_name (DBusConnection *connection,
805 const char *unique_name)
808 dbus_bool_t success = FALSE;
810 _dbus_return_val_if_fail (connection != NULL, FALSE);
811 _dbus_return_val_if_fail (unique_name != NULL, FALSE);
813 if (!_DBUS_LOCK (bus_datas))
815 /* do not "goto out", that would try to unlock */
819 bd = ensure_bus_data (connection);
823 _dbus_assert (bd->unique_name == NULL);
825 bd->unique_name = _dbus_strdup (unique_name);
826 success = bd->unique_name != NULL;
829 _DBUS_UNLOCK (bus_datas);
835 * Gets the unique name of the connection as assigned by the message
836 * bus. Only possible after the connection has been registered with
837 * the message bus. All connections returned by dbus_bus_get() or
838 * dbus_bus_get_private() have been successfully registered.
840 * The name remains valid until the connection is freed, and
841 * should not be freed by the caller.
843 * Other than dbus_bus_get(), there are two ways to set the unique
844 * name; one is dbus_bus_register(), the other is
845 * dbus_bus_set_unique_name(). You are responsible for calling
846 * dbus_bus_set_unique_name() if you register by hand instead of using
847 * dbus_bus_register().
849 * @param connection the connection
850 * @returns the unique name or #NULL on error
853 dbus_bus_get_unique_name (DBusConnection *connection)
856 const char *unique_name = NULL;
858 _dbus_return_val_if_fail (connection != NULL, NULL);
860 if (!_DBUS_LOCK (bus_datas))
862 /* We'd have initialized locks when we gave it its unique name, if it
863 * had one. Don't "goto out", that would try to unlock. */
867 bd = ensure_bus_data (connection);
871 unique_name = bd->unique_name;
874 _DBUS_UNLOCK (bus_datas);
880 * Asks the bus to return the UID the named connection authenticated
881 * as, if any. Only works on UNIX; only works for connections on the
882 * same machine as the bus. If you are not on the same machine as the
883 * bus, then calling this is probably a bad idea, since the UID will
884 * mean little to your application.
886 * For the system message bus you're guaranteed to be on the same
887 * machine since it only listens on a UNIX domain socket (at least,
888 * as shipped by default).
890 * This function only works for connections that authenticated as
891 * a UNIX user, right now that includes all bus connections, but
892 * it's very possible to have connections with no associated UID.
893 * So check for errors and do something sensible if they happen.
895 * This function will always return an error on Windows.
897 * @param connection the connection
898 * @param name a name owned by the connection
899 * @param error location to store the error
900 * @returns the unix user id, or ((unsigned)-1) if error is set
903 dbus_bus_get_unix_user (DBusConnection *connection,
907 DBusMessage *message, *reply;
910 _dbus_return_val_if_fail (connection != NULL, DBUS_UID_UNSET);
911 _dbus_return_val_if_fail (name != NULL, DBUS_UID_UNSET);
912 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), DBUS_UID_UNSET);
913 _dbus_return_val_if_error_is_set (error, DBUS_UID_UNSET);
915 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
918 "GetConnectionUnixUser");
922 _DBUS_SET_OOM (error);
923 return DBUS_UID_UNSET;
926 if (!dbus_message_append_args (message,
927 DBUS_TYPE_STRING, &name,
930 dbus_message_unref (message);
931 _DBUS_SET_OOM (error);
932 return DBUS_UID_UNSET;
935 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
938 dbus_message_unref (message);
942 _DBUS_ASSERT_ERROR_IS_SET (error);
943 return DBUS_UID_UNSET;
946 if (dbus_set_error_from_message (error, reply))
948 _DBUS_ASSERT_ERROR_IS_SET (error);
949 dbus_message_unref (reply);
950 return DBUS_UID_UNSET;
953 if (!dbus_message_get_args (reply, error,
954 DBUS_TYPE_UINT32, &uid,
957 _DBUS_ASSERT_ERROR_IS_SET (error);
958 dbus_message_unref (reply);
959 return DBUS_UID_UNSET;
962 dbus_message_unref (reply);
964 return (unsigned long) uid;
968 * Asks the bus to return its globally unique ID, as described in the
969 * D-Bus specification. For the session bus, this is useful as a way
970 * to uniquely identify each user session. For the system bus,
971 * probably the bus ID is not useful; instead, use the machine ID
972 * since it's accessible without necessarily connecting to the bus and
973 * may be persistent beyond a single bus instance (across reboots for
974 * example). See dbus_get_local_machine_id().
976 * In addition to an ID for each bus and an ID for each machine, there is
977 * an ID for each address that the bus is listening on; that can
978 * be retrieved with dbus_connection_get_server_id(), though it is
979 * probably not very useful.
981 * @param connection the connection
982 * @param error location to store the error
983 * @returns the bus ID or #NULL if error is set
986 dbus_bus_get_id (DBusConnection *connection,
989 DBusMessage *message, *reply;
991 const char *v_STRING;
993 _dbus_return_val_if_fail (connection != NULL, NULL);
994 _dbus_return_val_if_error_is_set (error, NULL);
996 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1001 if (message == NULL)
1003 _DBUS_SET_OOM (error);
1007 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
1010 dbus_message_unref (message);
1014 _DBUS_ASSERT_ERROR_IS_SET (error);
1018 if (dbus_set_error_from_message (error, reply))
1020 _DBUS_ASSERT_ERROR_IS_SET (error);
1021 dbus_message_unref (reply);
1026 if (!dbus_message_get_args (reply, error,
1027 DBUS_TYPE_STRING, &v_STRING,
1030 _DBUS_ASSERT_ERROR_IS_SET (error);
1031 dbus_message_unref (reply);
1035 id = _dbus_strdup (v_STRING); /* may be NULL */
1037 dbus_message_unref (reply);
1040 _DBUS_SET_OOM (error);
1042 /* FIXME it might be nice to cache the ID locally */
1048 * Asks the bus to assign the given name to this connection by invoking
1049 * the RequestName method on the bus. This method is fully documented
1050 * in the D-Bus specification. For quick reference, the flags and
1051 * result codes are discussed here, but the specification is the
1052 * canonical version of this information.
1054 * First you should know that for each bus name, the bus stores
1055 * a queue of connections that would like to own it. Only
1056 * one owns it at a time - called the primary owner. If the primary
1057 * owner releases the name or disconnects, then the next owner in the
1058 * queue atomically takes over.
1060 * So for example if you have an application org.freedesktop.TextEditor
1061 * and multiple instances of it can be run, you can have all of them
1062 * sitting in the queue. The first one to start up will receive messages
1063 * sent to org.freedesktop.TextEditor, but if that one exits another
1064 * will become the primary owner and receive messages.
1066 * The queue means you don't need to manually watch for the current owner to
1067 * disappear and then request the name again.
1069 * When requesting a name, you can specify several flags.
1071 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT and #DBUS_NAME_FLAG_DO_NOT_QUEUE
1072 * are properties stored by the bus for this connection with respect to
1073 * each requested bus name. These properties are stored even if the
1074 * connection is queued and does not become the primary owner.
1075 * You can update these flags by calling RequestName again (even if
1076 * you already own the name).
1078 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT means that another requestor of the
1079 * name can take it away from you by specifying #DBUS_NAME_FLAG_REPLACE_EXISTING.
1081 * #DBUS_NAME_FLAG_DO_NOT_QUEUE means that if you aren't the primary owner,
1082 * you don't want to be queued up - you only care about being the
1085 * Unlike the other two flags, #DBUS_NAME_FLAG_REPLACE_EXISTING is a property
1086 * of the individual RequestName call, i.e. the bus does not persistently
1087 * associate it with the connection-name pair. If a RequestName call includes
1088 * the #DBUS_NAME_FLAG_REPLACE_EXISTING flag, and the current primary
1089 * owner has #DBUS_NAME_FLAG_ALLOW_REPLACEMENT set, then the current primary
1090 * owner will be kicked off.
1092 * If no flags are given, an application will receive the requested
1093 * name only if the name is currently unowned; and it will NOT give
1094 * up the name if another application asks to take it over using
1095 * #DBUS_NAME_FLAG_REPLACE_EXISTING.
1097 * This function returns a result code. The possible result codes
1100 * #DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER means that the name had no
1101 * existing owner, and the caller is now the primary owner; or that
1102 * the name had an owner, and the caller specified
1103 * #DBUS_NAME_FLAG_REPLACE_EXISTING, and the current owner
1104 * specified #DBUS_NAME_FLAG_ALLOW_REPLACEMENT.
1106 * #DBUS_REQUEST_NAME_REPLY_IN_QUEUE happens only if the caller does NOT
1107 * specify #DBUS_NAME_FLAG_DO_NOT_QUEUE and either the current owner
1108 * did NOT specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT
1109 * specify #DBUS_NAME_FLAG_REPLACE_EXISTING. In this case the caller ends up
1110 * in a queue to own the name after the current owner gives it up.
1112 * #DBUS_REQUEST_NAME_REPLY_EXISTS happens if the name has an owner
1113 * already and the caller specifies #DBUS_NAME_FLAG_DO_NOT_QUEUE
1114 * and either the current owner has NOT specified
1115 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT specify
1116 * #DBUS_NAME_FLAG_REPLACE_EXISTING.
1118 * #DBUS_REQUEST_NAME_REPLY_ALREADY_OWNER happens if an application
1119 * requests a name it already owns. (Re-requesting a name is useful if
1120 * you want to change the #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or
1121 * #DBUS_NAME_FLAG_DO_NOT_QUEUE settings.)
1123 * When a service represents an application, say "text editor," then
1124 * it should specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT if it wants
1125 * the last editor started to be the user's editor vs. the first one
1126 * started. Then any editor that can be the user's editor should
1127 * specify #DBUS_NAME_FLAG_REPLACE_EXISTING to either take over
1128 * (last-started-wins) or be queued up (first-started-wins) according
1129 * to whether #DBUS_NAME_FLAG_ALLOW_REPLACEMENT was given.
1131 * Conventionally, single-instance applications often offer a command
1132 * line option called --replace which means to replace the current
1133 * instance. To implement this, always set
1134 * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT when you request your
1135 * application's bus name. When you lose ownership of your bus name,
1136 * you need to exit. Look for the signal "NameLost" from
1137 * #DBUS_SERVICE_DBUS and #DBUS_INTERFACE_DBUS (the signal's first
1138 * argument is the bus name that was lost). If starting up without
1139 * --replace, do not specify #DBUS_NAME_FLAG_REPLACE_EXISTING, and
1140 * exit if you fail to become the bus name owner. If --replace is
1141 * given, ask to replace the old owner.
1143 * @param connection the connection
1144 * @param name the name to request
1145 * @param flags flags
1146 * @param error location to store the error
1147 * @returns a result code, -1 if error is set
1150 dbus_bus_request_name (DBusConnection *connection,
1155 dbus_uint32_t result;
1157 _dbus_return_val_if_fail (connection != NULL, 0);
1158 _dbus_return_val_if_fail (name != NULL, 0);
1159 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0);
1160 _dbus_return_val_if_error_is_set (error, 0);
1162 if(!dbus_transport_is_kdbus(connection))
1164 DBusMessage *message, *reply;
1166 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1168 DBUS_INTERFACE_DBUS,
1170 if (message == NULL)
1172 _DBUS_SET_OOM (error);
1176 if (!dbus_message_append_args (message,
1177 DBUS_TYPE_STRING, &name,
1178 DBUS_TYPE_UINT32, &flags,
1181 dbus_message_unref (message);
1182 _DBUS_SET_OOM (error);
1186 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
1189 dbus_message_unref (message);
1193 _DBUS_ASSERT_ERROR_IS_SET (error);
1197 if (dbus_set_error_from_message (error, reply))
1199 _DBUS_ASSERT_ERROR_IS_SET (error);
1200 dbus_message_unref (reply);
1204 if (!dbus_message_get_args (reply, error,
1205 DBUS_TYPE_UINT32, &result,
1208 _DBUS_ASSERT_ERROR_IS_SET (error);
1209 dbus_message_unref (reply);
1213 dbus_message_unref (reply);
1217 if(!bus_register_policy_kdbus(name, connection, error))
1220 result = bus_request_name_kdbus(connection, name, flags, error);
1228 * Asks the bus to unassign the given name from this connection by
1229 * invoking the ReleaseName method on the bus. The "ReleaseName"
1230 * method is canonically documented in the D-Bus specification.
1232 * Possible results are: #DBUS_RELEASE_NAME_REPLY_RELEASED
1233 * which means you owned the name or were in the queue to own it,
1234 * and and now you don't own it and aren't in the queue.
1235 * #DBUS_RELEASE_NAME_REPLY_NOT_OWNER which means someone else
1236 * owns the name so you can't release it.
1237 * #DBUS_RELEASE_NAME_REPLY_NON_EXISTENT
1238 * which means nobody owned the name.
1240 * @param connection the connection
1241 * @param name the name to remove
1242 * @param error location to store the error
1243 * @returns a result code, -1 if error is set
1246 dbus_bus_release_name (DBusConnection *connection,
1250 DBusMessage *message, *reply;
1251 dbus_uint32_t result;
1253 _dbus_return_val_if_fail (connection != NULL, 0);
1254 _dbus_return_val_if_fail (name != NULL, 0);
1255 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0);
1256 _dbus_return_val_if_error_is_set (error, 0);
1258 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1260 DBUS_INTERFACE_DBUS,
1263 if (message == NULL)
1265 _DBUS_SET_OOM (error);
1269 if (!dbus_message_append_args (message,
1270 DBUS_TYPE_STRING, &name,
1273 dbus_message_unref (message);
1274 _DBUS_SET_OOM (error);
1278 reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
1281 dbus_message_unref (message);
1285 _DBUS_ASSERT_ERROR_IS_SET (error);
1289 if (dbus_set_error_from_message (error, reply))
1291 _DBUS_ASSERT_ERROR_IS_SET (error);
1292 dbus_message_unref (reply);
1296 if (!dbus_message_get_args (reply, error,
1297 DBUS_TYPE_UINT32, &result,
1300 _DBUS_ASSERT_ERROR_IS_SET (error);
1301 dbus_message_unref (reply);
1305 dbus_message_unref (reply);
1311 * Asks the bus whether a certain name has an owner.
1313 * Using this can easily result in a race condition,
1314 * since an owner can appear or disappear after you
1317 * If you want to request a name, just request it;
1318 * if you want to avoid replacing a current owner,
1319 * don't specify #DBUS_NAME_FLAG_REPLACE_EXISTING and
1320 * you will get an error if there's already an owner.
1322 * @param connection the connection
1323 * @param name the name
1324 * @param error location to store any errors
1325 * @returns #TRUE if the name exists, #FALSE if not or on error
1328 dbus_bus_name_has_owner (DBusConnection *connection,
1332 DBusMessage *message, *reply;
1335 _dbus_return_val_if_fail (connection != NULL, FALSE);
1336 _dbus_return_val_if_fail (name != NULL, FALSE);
1337 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE);
1338 _dbus_return_val_if_error_is_set (error, FALSE);
1340 message = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1342 DBUS_INTERFACE_DBUS,
1344 if (message == NULL)
1346 _DBUS_SET_OOM (error);
1350 if (!dbus_message_append_args (message,
1351 DBUS_TYPE_STRING, &name,
1354 dbus_message_unref (message);
1355 _DBUS_SET_OOM (error);
1359 reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
1360 dbus_message_unref (message);
1364 _DBUS_ASSERT_ERROR_IS_SET (error);
1368 if (!dbus_message_get_args (reply, error,
1369 DBUS_TYPE_BOOLEAN, &exists,
1372 _DBUS_ASSERT_ERROR_IS_SET (error);
1373 dbus_message_unref (reply);
1377 dbus_message_unref (reply);
1382 * Starts a service that will request ownership of the given name.
1383 * The returned result will be one of be one of
1384 * #DBUS_START_REPLY_SUCCESS or #DBUS_START_REPLY_ALREADY_RUNNING if
1385 * successful. Pass #NULL if you don't care about the result.
1387 * The flags parameter is for future expansion, currently you should
1390 * It's often easier to avoid explicitly starting services, and
1391 * just send a method call to the service's bus name instead.
1392 * Method calls start a service to handle them by default
1393 * unless you call dbus_message_set_auto_start() to disable this
1396 * @param connection the connection
1397 * @param name the name we want the new service to request
1398 * @param flags the flags (should always be 0 for now)
1399 * @param result a place to store the result or #NULL
1400 * @param error location to store any errors
1401 * @returns #TRUE if the activation succeeded, #FALSE if not
1404 dbus_bus_start_service_by_name (DBusConnection *connection,
1406 dbus_uint32_t flags,
1407 dbus_uint32_t *result,
1413 _dbus_return_val_if_fail (connection != NULL, FALSE);
1414 _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE);
1416 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1418 DBUS_INTERFACE_DBUS,
1419 "StartServiceByName");
1421 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &name,
1422 DBUS_TYPE_UINT32, &flags, DBUS_TYPE_INVALID))
1424 dbus_message_unref (msg);
1425 _DBUS_SET_OOM (error);
1429 reply = dbus_connection_send_with_reply_and_block (connection, msg,
1431 dbus_message_unref (msg);
1435 _DBUS_ASSERT_ERROR_IS_SET (error);
1439 if (dbus_set_error_from_message (error, reply))
1441 _DBUS_ASSERT_ERROR_IS_SET (error);
1442 dbus_message_unref (reply);
1446 if (result != NULL &&
1447 !dbus_message_get_args (reply, error, DBUS_TYPE_UINT32,
1448 result, DBUS_TYPE_INVALID))
1450 _DBUS_ASSERT_ERROR_IS_SET (error);
1451 dbus_message_unref (reply);
1455 dbus_message_unref (reply);
1460 send_no_return_values (DBusConnection *connection,
1466 /* Block to check success codepath */
1469 reply = dbus_connection_send_with_reply_and_block (connection, msg,
1473 _DBUS_ASSERT_ERROR_IS_SET (error);
1475 dbus_message_unref (reply);
1479 /* Silently-fail nonblocking codepath */
1480 dbus_message_set_no_reply (msg, TRUE);
1481 dbus_connection_send (connection, msg, NULL);
1486 * Adds a match rule to match messages going through the message bus.
1487 * The "rule" argument is the string form of a match rule.
1489 * If you pass #NULL for the error, this function will not
1490 * block; the match thus won't be added until you flush the
1491 * connection, and if there's an error adding the match
1492 * you won't find out about it. This is generally acceptable, since the
1493 * possible errors (including a lack of resources in the bus, the connection
1494 * having exceeded its quota of active match rules, or the match rule being
1495 * unparseable) are generally unrecoverable.
1497 * If you pass non-#NULL for the error this function will
1498 * block until it gets a reply. This may be useful when using match rule keys
1499 * introduced in recent versions of D-Bus, like 'arg0namespace', to allow the
1500 * application to fall back to less efficient match rules supported by older
1501 * versions of the daemon if the running version is not new enough; or when
1502 * using user-supplied rules rather than rules hard-coded at compile time.
1504 * Normal API conventions would have the function return
1505 * a boolean value indicating whether the error was set,
1506 * but that would require blocking always to determine
1509 * The AddMatch method is fully documented in the D-Bus
1510 * specification. For quick reference, the format of the
1511 * match rules is discussed here, but the specification
1512 * is the canonical version of this information.
1514 * Rules are specified as a string of comma separated
1515 * key/value pairs. An example is
1516 * "type='signal',sender='org.freedesktop.DBus',
1517 * interface='org.freedesktop.DBus',member='Foo',
1518 * path='/bar/foo',destination=':452345.34'"
1520 * Possible keys you can match on are type, sender,
1521 * interface, member, path, destination and numbered
1522 * keys to match message args (keys are 'arg0', 'arg1', etc.).
1523 * Omitting a key from the rule indicates
1524 * a wildcard match. For instance omitting
1525 * the member from a match rule but adding a sender would
1526 * let all messages from that sender through regardless of
1529 * Matches are inclusive not exclusive so as long as one
1530 * rule matches the message will get through. It is important
1531 * to note this because every time a message is received the
1532 * application will be paged into memory to process it. This
1533 * can cause performance problems such as draining batteries
1534 * on embedded platforms.
1536 * If you match message args ('arg0', 'arg1', and so forth)
1537 * only string arguments will match. That is, arg0='5' means
1538 * match the string "5" not the integer 5.
1540 * Currently there is no way to match against non-string arguments.
1542 * A specialised form of wildcard matching on arguments is
1543 * supported for path-like namespaces. If your argument match has
1544 * a 'path' suffix (eg: "arg0path='/some/path/'") then it is
1545 * considered a match if the argument exactly matches the given
1546 * string or if one of them ends in a '/' and is a prefix of the
1549 * Matching on interface is tricky because method call
1550 * messages only optionally specify the interface.
1551 * If a message omits the interface, then it will NOT match
1552 * if the rule specifies an interface name. This means match
1553 * rules on method calls should not usually give an interface.
1555 * However, signal messages are required to include the interface
1556 * so when matching signals usually you should specify the interface
1557 * in the match rule.
1559 * For security reasons, you can match arguments only up to
1560 * #DBUS_MAXIMUM_MATCH_RULE_ARG_NUMBER.
1562 * Match rules have a maximum length of #DBUS_MAXIMUM_MATCH_RULE_LENGTH
1565 * Both of these maximums are much higher than you're likely to need,
1566 * they only exist because the D-Bus bus daemon has fixed limits on
1567 * all resource usage.
1569 * @param connection connection to the message bus
1570 * @param rule textual form of match rule
1571 * @param error location to store any errors
1574 dbus_bus_add_match (DBusConnection *connection,
1578 _dbus_return_if_fail (rule != NULL);
1580 if(!dbus_transport_is_kdbus(connection))
1584 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1586 DBUS_INTERFACE_DBUS,
1591 _DBUS_SET_OOM (error);
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);
1608 dbus_bus_add_match_kdbus(connection, rule, error);
1612 * Removes a previously-added match rule "by value" (the most
1613 * recently-added identical rule gets removed). The "rule" argument
1614 * is the string form of a match rule.
1616 * The bus compares match rules semantically, not textually, so
1617 * whitespace and ordering don't have to be identical to
1618 * the rule you passed to dbus_bus_add_match().
1620 * If you pass #NULL for the error, this function will not
1621 * block; otherwise it will. See detailed explanation in
1622 * docs for dbus_bus_add_match().
1624 * @param connection connection to the message bus
1625 * @param rule textual form of match rule
1626 * @param error location to store any errors
1629 dbus_bus_remove_match (DBusConnection *connection,
1633 if(!dbus_transport_is_kdbus(connection))
1637 _dbus_return_if_fail (rule != NULL);
1639 msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS,
1641 DBUS_INTERFACE_DBUS,
1644 if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &rule,
1647 dbus_message_unref (msg);
1648 _DBUS_SET_OOM (error);
1652 send_no_return_values (connection, msg, error);
1654 dbus_message_unref (msg);
1657 dbus_bus_remove_match_kdbus(connection, error);