| /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */ |
| /* dbus-bus.c Convenience functions for communicating with the bus. |
| * |
| * Copyright (C) 2003 CodeFactory AB |
| * Copyright (C) 2003 Red Hat, Inc. |
| * |
| * Licensed under the Academic Free License version 2.1 |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| * |
| */ |
| |
| #include <config.h> |
| #include "dbus-bus.h" |
| #include "dbus-protocol.h" |
| #include "dbus-internals.h" |
| #include "dbus-message.h" |
| #include "dbus-marshal-validate.h" |
| #include "dbus-threads-internal.h" |
| #include "dbus-connection-internal.h" |
| #include "dbus-string.h" |
| |
| /** |
| * @defgroup DBusBus Message bus APIs |
| * @ingroup DBus |
| * @brief Functions for communicating with the message bus |
| * |
| * dbus_bus_get() allows all modules and libraries in a given |
| * process to share the same connection to the bus daemon by storing |
| * the connection globally. |
| * |
| * All other functions in this module are just convenience functions; |
| * most of them invoke methods on the bus daemon, by sending method |
| * call messages to #DBUS_SERVICE_DBUS. These convenience functions |
| * often make blocking method calls. If you don't want to block, |
| * you can send the method call messages manually in the same way |
| * you would any other method call message. |
| * |
| * This module is the only one in libdbus that's specific to |
| * communicating with the message bus daemon. The rest of the API can |
| * also be used for connecting to another application directly. |
| * |
| * @todo right now the default address of the system bus is hardcoded, |
| * so if you change it in the global config file suddenly you have to |
| * set DBUS_SYSTEM_BUS_ADDRESS env variable. Might be nice if the |
| * client lib somehow read the config file, or if the bus on startup |
| * somehow wrote out its address to a well-known spot, but might also |
| * not be worth it. |
| */ |
| |
| /** |
| * @defgroup DBusBusInternals Message bus APIs internals |
| * @ingroup DBusInternals |
| * @brief Internals of functions for communicating with the message bus |
| * |
| * @{ |
| */ |
| |
| /** |
| * Block of message-bus-related data we attach to each |
| * #DBusConnection used with these convenience functions. |
| * |
| */ |
| typedef struct |
| { |
| DBusConnection *connection; /**< Connection we're associated with */ |
| char *unique_name; /**< Unique name of this connection */ |
| |
| unsigned int is_well_known : 1; /**< Is one of the well-known connections in our global array */ |
| } BusData; |
| |
| /** The slot we have reserved to store BusData. |
| */ |
| static dbus_int32_t bus_data_slot = -1; |
| |
| /** Number of bus types */ |
| #define N_BUS_TYPES 3 |
| |
| static DBusConnection *bus_connections[N_BUS_TYPES]; |
| static char *bus_connection_addresses[N_BUS_TYPES] = { NULL, NULL, NULL }; |
| |
| static DBusBusType activation_bus_type = DBUS_BUS_STARTER; |
| |
| static dbus_bool_t initialized = FALSE; |
| |
| /** |
| * Lock for globals in this file |
| */ |
| _DBUS_DEFINE_GLOBAL_LOCK (bus); |
| |
| /** |
| * Global lock covering all BusData on any connection. The bet is |
| * that some lock contention is better than more memory |
| * for a per-connection lock, but it's tough to imagine it mattering |
| * either way. |
| */ |
| _DBUS_DEFINE_GLOBAL_LOCK (bus_datas); |
| |
| static void |
| addresses_shutdown_func (void *data) |
| { |
| int i; |
| |
| i = 0; |
| while (i < N_BUS_TYPES) |
| { |
| if (bus_connections[i] != NULL) |
| _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"); |
| |
| dbus_free (bus_connection_addresses[i]); |
| bus_connection_addresses[i] = NULL; |
| ++i; |
| } |
| |
| activation_bus_type = DBUS_BUS_STARTER; |
| |
| initialized = FALSE; |
| } |
| |
| static dbus_bool_t |
| get_from_env (char **connection_p, |
| const char *env_var) |
| { |
| const char *s; |
| |
| _dbus_assert (*connection_p == NULL); |
| |
| s = _dbus_getenv (env_var); |
| if (s == NULL || *s == '\0') |
| return TRUE; /* successfully didn't use the env var */ |
| else |
| { |
| *connection_p = _dbus_strdup (s); |
| return *connection_p != NULL; |
| } |
| } |
| |
| static dbus_bool_t |
| init_session_address (void) |
| { |
| dbus_bool_t retval; |
| |
| retval = FALSE; |
| |
| /* First, look in the environment. This is the normal case on |
| * freedesktop.org/Unix systems. */ |
| get_from_env (&bus_connection_addresses[DBUS_BUS_SESSION], |
| "DBUS_SESSION_BUS_ADDRESS"); |
| if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL) |
| { |
| dbus_bool_t supported; |
| DBusString addr; |
| DBusError error = DBUS_ERROR_INIT; |
| |
| if (!_dbus_string_init (&addr)) |
| return FALSE; |
| |
| supported = FALSE; |
| /* So it's not in the environment - let's try a platform-specific method. |
| * On MacOS, this involves asking launchd. On Windows (not specified yet) |
| * we might do a COM lookup. |
| * Ignore errors - if we failed, fall back to autolaunch. */ |
| retval = _dbus_lookup_session_address (&supported, &addr, &error); |
| if (supported && retval) |
| { |
| retval =_dbus_string_steal_data (&addr, &bus_connection_addresses[DBUS_BUS_SESSION]); |
| } |
| else if (supported && !retval) |
| { |
| if (dbus_error_is_set(&error)) |
| _dbus_warn ("Dynamic session lookup supported but failed: %s\n", error.message); |
| else |
| _dbus_warn ("Dynamic session lookup supported but failed silently\n"); |
| } |
| _dbus_string_free (&addr); |
| } |
| else |
| retval = TRUE; |
| |
| if (!retval) |
| return FALSE; |
| |
| /* The DBUS_SESSION_BUS_DEFAULT_ADDRESS should have really been named |
| * DBUS_SESSION_BUS_FALLBACK_ADDRESS. |
| */ |
| if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL) |
| bus_connection_addresses[DBUS_BUS_SESSION] = |
| _dbus_strdup (DBUS_SESSION_BUS_DEFAULT_ADDRESS); |
| if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL) |
| return FALSE; |
| |
| return TRUE; |
| } |
| |
| static dbus_bool_t |
| init_connections_unlocked (void) |
| { |
| if (!initialized) |
| { |
| const char *s; |
| int i; |
| |
| i = 0; |
| while (i < N_BUS_TYPES) |
| { |
| bus_connections[i] = NULL; |
| ++i; |
| } |
| |
| /* Don't init these twice, we may run this code twice if |
| * init_connections_unlocked() fails midway through. |
| * In practice, each block below should contain only one |
| * "return FALSE" or running through twice may not |
| * work right. |
| */ |
| |
| if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL) |
| { |
| _dbus_verbose ("Filling in system bus address...\n"); |
| |
| if (!get_from_env (&bus_connection_addresses[DBUS_BUS_SYSTEM], |
| "DBUS_SYSTEM_BUS_ADDRESS")) |
| return FALSE; |
| } |
| |
| |
| if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL) |
| { |
| /* Use default system bus address if none set in environment */ |
| bus_connection_addresses[DBUS_BUS_SYSTEM] = |
| _dbus_strdup (DBUS_SYSTEM_BUS_DEFAULT_ADDRESS); |
| |
| if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL) |
| return FALSE; |
| |
| _dbus_verbose (" used default system bus \"%s\"\n", |
| bus_connection_addresses[DBUS_BUS_SYSTEM]); |
| } |
| else |
| _dbus_verbose (" used env var system bus \"%s\"\n", |
| bus_connection_addresses[DBUS_BUS_SYSTEM]); |
| |
| if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL) |
| { |
| _dbus_verbose ("Filling in session bus address...\n"); |
| |
| if (!init_session_address ()) |
| return FALSE; |
| |
| _dbus_verbose (" \"%s\"\n", bus_connection_addresses[DBUS_BUS_SESSION] ? |
| bus_connection_addresses[DBUS_BUS_SESSION] : "none set"); |
| } |
| |
| if (bus_connection_addresses[DBUS_BUS_STARTER] == NULL) |
| { |
| _dbus_verbose ("Filling in activation bus address...\n"); |
| |
| if (!get_from_env (&bus_connection_addresses[DBUS_BUS_STARTER], |
| "DBUS_STARTER_ADDRESS")) |
| return FALSE; |
| |
| _dbus_verbose (" \"%s\"\n", bus_connection_addresses[DBUS_BUS_STARTER] ? |
| bus_connection_addresses[DBUS_BUS_STARTER] : "none set"); |
| } |
| |
| |
| if (bus_connection_addresses[DBUS_BUS_STARTER] != NULL) |
| { |
| s = _dbus_getenv ("DBUS_STARTER_BUS_TYPE"); |
| |
| if (s != NULL) |
| { |
| _dbus_verbose ("Bus activation type was set to \"%s\"\n", s); |
| |
| if (strcmp (s, "system") == 0) |
| activation_bus_type = DBUS_BUS_SYSTEM; |
| else if (strcmp (s, "session") == 0) |
| activation_bus_type = DBUS_BUS_SESSION; |
| } |
| } |
| else |
| { |
| /* Default to the session bus instead if available */ |
| if (bus_connection_addresses[DBUS_BUS_SESSION] != NULL) |
| { |
| bus_connection_addresses[DBUS_BUS_STARTER] = |
| _dbus_strdup (bus_connection_addresses[DBUS_BUS_SESSION]); |
| if (bus_connection_addresses[DBUS_BUS_STARTER] == NULL) |
| return FALSE; |
| } |
| } |
| |
| /* If we return FALSE we have to be sure that restarting |
| * the above code will work right |
| */ |
| |
| if (!_dbus_setenv ("DBUS_ACTIVATION_ADDRESS", NULL)) |
| return FALSE; |
| |
| if (!_dbus_setenv ("DBUS_ACTIVATION_BUS_TYPE", NULL)) |
| return FALSE; |
| |
| if (!_dbus_register_shutdown_func (addresses_shutdown_func, |
| NULL)) |
| return FALSE; |
| |
| initialized = TRUE; |
| } |
| |
| return initialized; |
| } |
| |
| static void |
| bus_data_free (void *data) |
| { |
| BusData *bd = data; |
| |
| if (bd->is_well_known) |
| { |
| int i; |
| _DBUS_LOCK (bus); |
| /* We may be stored in more than one slot */ |
| /* This should now be impossible - these slots are supposed to |
| * be cleared on disconnect, so should not need to be cleared on |
| * finalize |
| */ |
| i = 0; |
| while (i < N_BUS_TYPES) |
| { |
| if (bus_connections[i] == bd->connection) |
| bus_connections[i] = NULL; |
| |
| ++i; |
| } |
| _DBUS_UNLOCK (bus); |
| } |
| |
| dbus_free (bd->unique_name); |
| dbus_free (bd); |
| |
| dbus_connection_free_data_slot (&bus_data_slot); |
| } |
| |
| static BusData* |
| ensure_bus_data (DBusConnection *connection) |
| { |
| BusData *bd; |
| |
| if (!dbus_connection_allocate_data_slot (&bus_data_slot)) |
| return NULL; |
| |
| bd = dbus_connection_get_data (connection, bus_data_slot); |
| if (bd == NULL) |
| { |
| bd = dbus_new0 (BusData, 1); |
| if (bd == NULL) |
| { |
| dbus_connection_free_data_slot (&bus_data_slot); |
| return NULL; |
| } |
| |
| bd->connection = connection; |
| |
| if (!dbus_connection_set_data (connection, bus_data_slot, bd, |
| bus_data_free)) |
| { |
| dbus_free (bd); |
| dbus_connection_free_data_slot (&bus_data_slot); |
| return NULL; |
| } |
| |
| /* Data slot refcount now held by the BusData */ |
| } |
| else |
| { |
| dbus_connection_free_data_slot (&bus_data_slot); |
| } |
| |
| return bd; |
| } |
| |
| /** |
| * Internal function that checks to see if this |
| * is a shared connection owned by the bus and if it is unref it. |
| * |
| * @param connection a connection that has been disconnected. |
| */ |
| void |
| _dbus_bus_notify_shared_connection_disconnected_unlocked (DBusConnection *connection) |
| { |
| int i; |
| |
| _DBUS_LOCK (bus); |
| |
| /* We are expecting to have the connection saved in only one of these |
| * slots, but someone could in a pathological case set system and session |
| * bus to the same bus or something. Or set one of them to the starter |
| * bus without setting the starter bus type in the env variable. |
| * So we don't break the loop as soon as we find a match. |
| */ |
| for (i = 0; i < N_BUS_TYPES; ++i) |
| { |
| if (bus_connections[i] == connection) |
| { |
| bus_connections[i] = NULL; |
| } |
| } |
| |
| _DBUS_UNLOCK (bus); |
| } |
| |
| static DBusConnection * |
| internal_bus_get (DBusBusType type, |
| dbus_bool_t private, |
| DBusError *error) |
| { |
| const char *address; |
| DBusConnection *connection; |
| BusData *bd; |
| DBusBusType address_type; |
| |
| _dbus_return_val_if_fail (type >= 0 && type < N_BUS_TYPES, NULL); |
| _dbus_return_val_if_error_is_set (error, NULL); |
| |
| _DBUS_LOCK (bus); |
| |
| if (!init_connections_unlocked ()) |
| { |
| _DBUS_UNLOCK (bus); |
| _DBUS_SET_OOM (error); |
| return NULL; |
| } |
| |
| /* We want to use the activation address even if the |
| * activating bus is the session or system bus, |
| * per the spec. |
| */ |
| address_type = type; |
| |
| /* Use the real type of the activation bus for getting its |
| * connection, but only if the real type's address is available. (If |
| * the activating bus isn't a well-known bus then |
| * activation_bus_type == DBUS_BUS_STARTER) |
| */ |
| if (type == DBUS_BUS_STARTER && |
| bus_connection_addresses[activation_bus_type] != NULL) |
| type = activation_bus_type; |
| |
| if (!private && bus_connections[type] != NULL) |
| { |
| connection = bus_connections[type]; |
| dbus_connection_ref (connection); |
| |
| _DBUS_UNLOCK (bus); |
| return connection; |
| } |
| |
| address = bus_connection_addresses[address_type]; |
| if (address == NULL) |
| { |
| dbus_set_error (error, DBUS_ERROR_FAILED, |
| "Unable to determine the address of the message bus (try 'man dbus-launch' and 'man dbus-daemon' for help)"); |
| _DBUS_UNLOCK (bus); |
| return NULL; |
| } |
| |
| if (private) |
| connection = dbus_connection_open_private (address, error); |
| else |
| connection = dbus_connection_open (address, error); |
| |
| if (!connection) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| _DBUS_UNLOCK (bus); |
| return NULL; |
| } |
| |
| if (!dbus_bus_register (connection, error)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| _dbus_connection_close_possibly_shared (connection); |
| dbus_connection_unref (connection); |
| |
| _DBUS_UNLOCK (bus); |
| return NULL; |
| } |
| |
| if (!private) |
| { |
| /* store a weak ref to the connection (dbus-connection.c is |
| * supposed to have a strong ref that it drops on disconnect, |
| * since this is a shared connection) |
| */ |
| bus_connections[type] = connection; |
| } |
| |
| /* By default we're bound to the lifecycle of |
| * the message bus. |
| */ |
| dbus_connection_set_exit_on_disconnect (connection, |
| TRUE); |
| |
| _DBUS_LOCK (bus_datas); |
| bd = ensure_bus_data (connection); |
| _dbus_assert (bd != NULL); /* it should have been created on |
| register, so OOM not possible */ |
| bd->is_well_known = TRUE; |
| _DBUS_UNLOCK (bus_datas); |
| |
| |
| _DBUS_UNLOCK (bus); |
| |
| /* Return a reference to the caller */ |
| return connection; |
| } |
| |
| |
| /** @} */ /* end of implementation details docs */ |
| |
| /** |
| * @addtogroup DBusBus |
| * @{ |
| */ |
| |
| /** |
| * Connects to a bus daemon and registers the client with it. If a |
| * connection to the bus already exists, then that connection is |
| * returned. The caller of this function owns a reference to the bus. |
| * |
| * The caller may NOT call dbus_connection_close() on this connection; |
| * see dbus_connection_open() and dbus_connection_close() for details |
| * on that. |
| * |
| * If this function obtains a new connection object never before |
| * returned from dbus_bus_get(), it will call |
| * dbus_connection_set_exit_on_disconnect(), so the application |
| * will exit if the connection closes. You can undo this |
| * by calling dbus_connection_set_exit_on_disconnect() yourself |
| * after you get the connection. |
| * |
| * dbus_bus_get() calls dbus_bus_register() for you. |
| * |
| * If returning a newly-created connection, this function will block |
| * until authentication and bus registration are complete. |
| * |
| * @param type bus type |
| * @param error address where an error can be returned. |
| * @returns a #DBusConnection with new ref |
| */ |
| DBusConnection * |
| dbus_bus_get (DBusBusType type, |
| DBusError *error) |
| { |
| return internal_bus_get (type, FALSE, error); |
| } |
| |
| /** |
| * Connects to a bus daemon and registers the client with it as with |
| * dbus_bus_register(). Unlike dbus_bus_get(), always creates a new |
| * connection. This connection will not be saved or recycled by |
| * libdbus. Caller owns a reference to the bus and must either close |
| * it or know it to be closed prior to releasing this reference. |
| * |
| * See dbus_connection_open_private() for more details on when to |
| * close and unref this connection. |
| * |
| * This function calls |
| * dbus_connection_set_exit_on_disconnect() on the new connection, so the application |
| * will exit if the connection closes. You can undo this |
| * by calling dbus_connection_set_exit_on_disconnect() yourself |
| * after you get the connection. |
| * |
| * dbus_bus_get_private() calls dbus_bus_register() for you. |
| * |
| * This function will block until authentication and bus registration |
| * are complete. |
| * |
| * @param type bus type |
| * @param error address where an error can be returned. |
| * @returns a DBusConnection with new ref |
| */ |
| DBusConnection * |
| dbus_bus_get_private (DBusBusType type, |
| DBusError *error) |
| { |
| return internal_bus_get (type, TRUE, error); |
| } |
| |
| /** |
| * Registers a connection with the bus. This must be the first |
| * thing an application does when connecting to the message bus. |
| * If registration succeeds, the unique name will be set, |
| * and can be obtained using dbus_bus_get_unique_name(). |
| * |
| * This function will block until registration is complete. |
| * |
| * If the connection has already registered with the bus |
| * (determined by checking whether dbus_bus_get_unique_name() |
| * returns a non-#NULL value), then this function does nothing. |
| * |
| * If you use dbus_bus_get() or dbus_bus_get_private() this |
| * function will be called for you. |
| * |
| * @note Just use dbus_bus_get() or dbus_bus_get_private() instead of |
| * dbus_bus_register() and save yourself some pain. Using |
| * dbus_bus_register() manually is only useful if you have your |
| * own custom message bus not found in #DBusBusType. |
| * |
| * If you open a bus connection with dbus_connection_open() or |
| * dbus_connection_open_private() you will have to dbus_bus_register() |
| * yourself, or make the appropriate registration method calls |
| * yourself. If you send the method calls yourself, call |
| * dbus_bus_set_unique_name() with the unique bus name you get from |
| * the bus. |
| * |
| * For shared connections (created with dbus_connection_open()) in a |
| * multithreaded application, you can't really make the registration |
| * calls yourself, because you don't know whether some other thread is |
| * also registering, and the bus will kick you off if you send two |
| * registration messages. |
| * |
| * If you use dbus_bus_register() however, there is a lock that |
| * keeps both apps from registering at the same time. |
| * |
| * The rule in a multithreaded app, then, is that dbus_bus_register() |
| * must be used to register, or you need to have your own locks that |
| * all threads in the app will respect. |
| * |
| * In a single-threaded application you can register by hand instead |
| * of using dbus_bus_register(), as long as you check |
| * dbus_bus_get_unique_name() to see if a unique name has already been |
| * stored by another thread before you send the registration messages. |
| * |
| * @param connection the connection |
| * @param error place to store errors |
| * @returns #TRUE on success |
| */ |
| dbus_bool_t |
| dbus_bus_register (DBusConnection *connection, |
| DBusError *error) |
| { |
| DBusMessage *message, *reply; |
| char *name; |
| BusData *bd; |
| dbus_bool_t retval; |
| |
| _dbus_return_val_if_fail (connection != NULL, FALSE); |
| _dbus_return_val_if_error_is_set (error, FALSE); |
| |
| retval = FALSE; |
| |
| _DBUS_LOCK (bus_datas); |
| |
| bd = ensure_bus_data (connection); |
| if (bd == NULL) |
| { |
| _DBUS_SET_OOM (error); |
| _DBUS_UNLOCK (bus_datas); |
| return FALSE; |
| } |
| |
| if (bd->unique_name != NULL) |
| { |
| _dbus_verbose ("Ignoring attempt to register the same DBusConnection %s with the message bus a second time.\n", |
| bd->unique_name); |
| _DBUS_UNLOCK (bus_datas); |
| |
| /* Success! */ |
| return TRUE; |
| } |
| |
| message = dbus_message_new_method_call (DBUS_SERVICE_DBUS, |
| DBUS_PATH_DBUS, |
| DBUS_INTERFACE_DBUS, |
| "Hello"); |
| |
| if (!message) |
| { |
| _DBUS_SET_OOM (error); |
| |
| _DBUS_UNLOCK (bus_datas); |
| return FALSE; |
| } |
| |
| reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error); |
| |
| dbus_message_unref (message); |
| |
| if (reply == NULL) |
| goto out; |
| else if (dbus_set_error_from_message (error, reply)) |
| goto out; |
| else if (!dbus_message_get_args (reply, error, |
| DBUS_TYPE_STRING, &name, |
| DBUS_TYPE_INVALID)) |
| goto out; |
| |
| bd->unique_name = _dbus_strdup (name); |
| if (bd->unique_name == NULL) |
| { |
| _DBUS_SET_OOM (error); |
| goto out; |
| } |
| |
| retval = TRUE; |
| |
| out: |
| if (reply) |
| dbus_message_unref (reply); |
| |
| if (!retval) |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| |
| _DBUS_UNLOCK (bus_datas); |
| |
| return retval; |
| } |
| |
| |
| /** |
| * Sets the unique name of the connection, as assigned by the message |
| * bus. Can only be used if you registered with the bus manually |
| * (i.e. if you did not call dbus_bus_register()). Can only be called |
| * once per connection. After the unique name is set, you can get it |
| * with dbus_bus_get_unique_name(). |
| * |
| * The only reason to use this function is to re-implement the |
| * equivalent of dbus_bus_register() yourself. One (probably unusual) |
| * reason to do that might be to do the bus registration call |
| * asynchronously instead of synchronously. |
| * |
| * @note Just use dbus_bus_get() or dbus_bus_get_private(), or worst |
| * case dbus_bus_register(), instead of messing with this |
| * function. There's really no point creating pain for yourself by |
| * doing things manually. |
| * |
| * It's hard to use this function safely on shared connections |
| * (created by dbus_connection_open()) in a multithreaded application, |
| * because only one registration attempt can be sent to the bus. If |
| * two threads are both sending the registration message, there is no |
| * mechanism in libdbus itself to avoid sending it twice. |
| * |
| * Thus, you need a way to coordinate which thread sends the |
| * registration attempt; which also means you know which thread |
| * will call dbus_bus_set_unique_name(). If you don't know |
| * about all threads in the app (for example, if some libraries |
| * you're using might start libdbus-using threads), then you |
| * need to avoid using this function on shared connections. |
| * |
| * @param connection the connection |
| * @param unique_name the unique name |
| * @returns #FALSE if not enough memory |
| */ |
| dbus_bool_t |
| dbus_bus_set_unique_name (DBusConnection *connection, |
| const char *unique_name) |
| { |
| BusData *bd; |
| dbus_bool_t success = FALSE; |
| |
| _dbus_return_val_if_fail (connection != NULL, FALSE); |
| _dbus_return_val_if_fail (unique_name != NULL, FALSE); |
| |
| _DBUS_LOCK (bus_datas); |
| |
| bd = ensure_bus_data (connection); |
| if (bd == NULL) |
| goto out; |
| |
| _dbus_assert (bd->unique_name == NULL); |
| |
| bd->unique_name = _dbus_strdup (unique_name); |
| success = bd->unique_name != NULL; |
| |
| out: |
| _DBUS_UNLOCK (bus_datas); |
| |
| return success; |
| } |
| |
| /** |
| * Gets the unique name of the connection as assigned by the message |
| * bus. Only possible after the connection has been registered with |
| * the message bus. All connections returned by dbus_bus_get() or |
| * dbus_bus_get_private() have been successfully registered. |
| * |
| * The name remains valid until the connection is freed, and |
| * should not be freed by the caller. |
| * |
| * Other than dbus_bus_get(), there are two ways to set the unique |
| * name; one is dbus_bus_register(), the other is |
| * dbus_bus_set_unique_name(). You are responsible for calling |
| * dbus_bus_set_unique_name() if you register by hand instead of using |
| * dbus_bus_register(). |
| * |
| * @param connection the connection |
| * @returns the unique name or #NULL on error |
| */ |
| const char* |
| dbus_bus_get_unique_name (DBusConnection *connection) |
| { |
| BusData *bd; |
| const char *unique_name = NULL; |
| |
| _dbus_return_val_if_fail (connection != NULL, NULL); |
| |
| _DBUS_LOCK (bus_datas); |
| |
| bd = ensure_bus_data (connection); |
| if (bd == NULL) |
| goto out; |
| |
| unique_name = bd->unique_name; |
| |
| out: |
| _DBUS_UNLOCK (bus_datas); |
| |
| return unique_name; |
| } |
| |
| /** |
| * Asks the bus to return the UID the named connection authenticated |
| * as, if any. Only works on UNIX; only works for connections on the |
| * same machine as the bus. If you are not on the same machine as the |
| * bus, then calling this is probably a bad idea, since the UID will |
| * mean little to your application. |
| * |
| * For the system message bus you're guaranteed to be on the same |
| * machine since it only listens on a UNIX domain socket (at least, |
| * as shipped by default). |
| * |
| * This function only works for connections that authenticated as |
| * a UNIX user, right now that includes all bus connections, but |
| * it's very possible to have connections with no associated UID. |
| * So check for errors and do something sensible if they happen. |
| * |
| * This function will always return an error on Windows. |
| * |
| * @param connection the connection |
| * @param name a name owned by the connection |
| * @param error location to store the error |
| * @returns the unix user id, or ((unsigned)-1) if error is set |
| */ |
| unsigned long |
| dbus_bus_get_unix_user (DBusConnection *connection, |
| const char *name, |
| DBusError *error) |
| { |
| DBusMessage *message, *reply; |
| dbus_uint32_t uid; |
| |
| _dbus_return_val_if_fail (connection != NULL, DBUS_UID_UNSET); |
| _dbus_return_val_if_fail (name != NULL, DBUS_UID_UNSET); |
| _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), DBUS_UID_UNSET); |
| _dbus_return_val_if_error_is_set (error, DBUS_UID_UNSET); |
| |
| message = dbus_message_new_method_call (DBUS_SERVICE_DBUS, |
| DBUS_PATH_DBUS, |
| DBUS_INTERFACE_DBUS, |
| "GetConnectionUnixUser"); |
| |
| if (message == NULL) |
| { |
| _DBUS_SET_OOM (error); |
| return DBUS_UID_UNSET; |
| } |
| |
| if (!dbus_message_append_args (message, |
| DBUS_TYPE_STRING, &name, |
| DBUS_TYPE_INVALID)) |
| { |
| dbus_message_unref (message); |
| _DBUS_SET_OOM (error); |
| return DBUS_UID_UNSET; |
| } |
| |
| reply = dbus_connection_send_with_reply_and_block (connection, message, -1, |
| error); |
| |
| dbus_message_unref (message); |
| |
| if (reply == NULL) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| return DBUS_UID_UNSET; |
| } |
| |
| if (dbus_set_error_from_message (error, reply)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| dbus_message_unref (reply); |
| return DBUS_UID_UNSET; |
| } |
| |
| if (!dbus_message_get_args (reply, error, |
| DBUS_TYPE_UINT32, &uid, |
| DBUS_TYPE_INVALID)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| dbus_message_unref (reply); |
| return DBUS_UID_UNSET; |
| } |
| |
| dbus_message_unref (reply); |
| |
| return (unsigned long) uid; |
| } |
| |
| /** |
| * Asks the bus to return its globally unique ID, as described in the |
| * D-Bus specification. For the session bus, this is useful as a way |
| * to uniquely identify each user session. For the system bus, |
| * probably the bus ID is not useful; instead, use the machine ID |
| * since it's accessible without necessarily connecting to the bus and |
| * may be persistent beyond a single bus instance (across reboots for |
| * example). See dbus_get_local_machine_id(). |
| * |
| * In addition to an ID for each bus and an ID for each machine, there is |
| * an ID for each address that the bus is listening on; that can |
| * be retrieved with dbus_connection_get_server_id(), though it is |
| * probably not very useful. |
| * |
| * @param connection the connection |
| * @param error location to store the error |
| * @returns the bus ID or #NULL if error is set |
| */ |
| char* |
| dbus_bus_get_id (DBusConnection *connection, |
| DBusError *error) |
| { |
| DBusMessage *message, *reply; |
| char *id; |
| const char *v_STRING; |
| |
| _dbus_return_val_if_fail (connection != NULL, NULL); |
| _dbus_return_val_if_error_is_set (error, NULL); |
| |
| message = dbus_message_new_method_call (DBUS_SERVICE_DBUS, |
| DBUS_PATH_DBUS, |
| DBUS_INTERFACE_DBUS, |
| "GetId"); |
| |
| if (message == NULL) |
| { |
| _DBUS_SET_OOM (error); |
| return NULL; |
| } |
| |
| reply = dbus_connection_send_with_reply_and_block (connection, message, -1, |
| error); |
| |
| dbus_message_unref (message); |
| |
| if (reply == NULL) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| return NULL; |
| } |
| |
| if (dbus_set_error_from_message (error, reply)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| dbus_message_unref (reply); |
| return NULL; |
| } |
| |
| v_STRING = NULL; |
| if (!dbus_message_get_args (reply, error, |
| DBUS_TYPE_STRING, &v_STRING, |
| DBUS_TYPE_INVALID)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| dbus_message_unref (reply); |
| return NULL; |
| } |
| |
| id = _dbus_strdup (v_STRING); /* may be NULL */ |
| |
| dbus_message_unref (reply); |
| |
| if (id == NULL) |
| _DBUS_SET_OOM (error); |
| |
| /* FIXME it might be nice to cache the ID locally */ |
| |
| return id; |
| } |
| |
| /** |
| * Asks the bus to assign the given name to this connection by invoking |
| * the RequestName method on the bus. This method is fully documented |
| * in the D-Bus specification. For quick reference, the flags and |
| * result codes are discussed here, but the specification is the |
| * canonical version of this information. |
| * |
| * First you should know that for each bus name, the bus stores |
| * a queue of connections that would like to own it. Only |
| * one owns it at a time - called the primary owner. If the primary |
| * owner releases the name or disconnects, then the next owner in the |
| * queue atomically takes over. |
| * |
| * So for example if you have an application org.freedesktop.TextEditor |
| * and multiple instances of it can be run, you can have all of them |
| * sitting in the queue. The first one to start up will receive messages |
| * sent to org.freedesktop.TextEditor, but if that one exits another |
| * will become the primary owner and receive messages. |
| * |
| * The queue means you don't need to manually watch for the current owner to |
| * disappear and then request the name again. |
| * |
| * When requesting a name, you can specify several flags. |
| * |
| * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT and #DBUS_NAME_FLAG_DO_NOT_QUEUE |
| * are properties stored by the bus for this connection with respect to |
| * each requested bus name. These properties are stored even if the |
| * connection is queued and does not become the primary owner. |
| * You can update these flags by calling RequestName again (even if |
| * you already own the name). |
| * |
| * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT means that another requestor of the |
| * name can take it away from you by specifying #DBUS_NAME_FLAG_REPLACE_EXISTING. |
| * |
| * #DBUS_NAME_FLAG_DO_NOT_QUEUE means that if you aren't the primary owner, |
| * you don't want to be queued up - you only care about being the |
| * primary owner. |
| * |
| * Unlike the other two flags, #DBUS_NAME_FLAG_REPLACE_EXISTING is a property |
| * of the individual RequestName call, i.e. the bus does not persistently |
| * associate it with the connection-name pair. If a RequestName call includes |
| * the #DBUS_NAME_FLAG_REPLACE_EXISTING flag, and the current primary |
| * owner has #DBUS_NAME_FLAG_ALLOW_REPLACEMENT set, then the current primary |
| * owner will be kicked off. |
| * |
| * If no flags are given, an application will receive the requested |
| * name only if the name is currently unowned; and it will NOT give |
| * up the name if another application asks to take it over using |
| * #DBUS_NAME_FLAG_REPLACE_EXISTING. |
| * |
| * This function returns a result code. The possible result codes |
| * are as follows. |
| * |
| * #DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER means that the name had no |
| * existing owner, and the caller is now the primary owner; or that |
| * the name had an owner, and the caller specified |
| * #DBUS_NAME_FLAG_REPLACE_EXISTING, and the current owner |
| * specified #DBUS_NAME_FLAG_ALLOW_REPLACEMENT. |
| * |
| * #DBUS_REQUEST_NAME_REPLY_IN_QUEUE happens only if the caller does NOT |
| * specify #DBUS_NAME_FLAG_DO_NOT_QUEUE and either the current owner |
| * did NOT specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT |
| * specify #DBUS_NAME_FLAG_REPLACE_EXISTING. In this case the caller ends up |
| * in a queue to own the name after the current owner gives it up. |
| * |
| * #DBUS_REQUEST_NAME_REPLY_EXISTS happens if the name has an owner |
| * already and the caller specifies #DBUS_NAME_FLAG_DO_NOT_QUEUE |
| * and either the current owner has NOT specified |
| * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or the caller did NOT specify |
| * #DBUS_NAME_FLAG_REPLACE_EXISTING. |
| * |
| * #DBUS_REQUEST_NAME_REPLY_ALREADY_OWNER happens if an application |
| * requests a name it already owns. (Re-requesting a name is useful if |
| * you want to change the #DBUS_NAME_FLAG_ALLOW_REPLACEMENT or |
| * #DBUS_NAME_FLAG_DO_NOT_QUEUE settings.) |
| * |
| * When a service represents an application, say "text editor," then |
| * it should specify #DBUS_NAME_FLAG_ALLOW_REPLACEMENT if it wants |
| * the last editor started to be the user's editor vs. the first one |
| * started. Then any editor that can be the user's editor should |
| * specify #DBUS_NAME_FLAG_REPLACE_EXISTING to either take over |
| * (last-started-wins) or be queued up (first-started-wins) according |
| * to whether #DBUS_NAME_FLAG_ALLOW_REPLACEMENT was given. |
| * |
| * Conventionally, single-instance applications often offer a command |
| * line option called --replace which means to replace the current |
| * instance. To implement this, always set |
| * #DBUS_NAME_FLAG_ALLOW_REPLACEMENT when you request your |
| * application's bus name. When you lose ownership of your bus name, |
| * you need to exit. Look for the signal "NameLost" from |
| * #DBUS_SERVICE_DBUS and #DBUS_INTERFACE_DBUS (the signal's first |
| * argument is the bus name that was lost). If starting up without |
| * --replace, do not specify #DBUS_NAME_FLAG_REPLACE_EXISTING, and |
| * exit if you fail to become the bus name owner. If --replace is |
| * given, ask to replace the old owner. |
| * |
| * @param connection the connection |
| * @param name the name to request |
| * @param flags flags |
| * @param error location to store the error |
| * @returns a result code, -1 if error is set |
| */ |
| int |
| dbus_bus_request_name (DBusConnection *connection, |
| const char *name, |
| unsigned int flags, |
| DBusError *error) |
| { |
| DBusMessage *message, *reply; |
| dbus_uint32_t result; |
| |
| _dbus_return_val_if_fail (connection != NULL, 0); |
| _dbus_return_val_if_fail (name != NULL, 0); |
| _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0); |
| _dbus_return_val_if_error_is_set (error, 0); |
| |
| message = dbus_message_new_method_call (DBUS_SERVICE_DBUS, |
| DBUS_PATH_DBUS, |
| DBUS_INTERFACE_DBUS, |
| "RequestName"); |
| |
| if (message == NULL) |
| { |
| _DBUS_SET_OOM (error); |
| return -1; |
| } |
| |
| if (!dbus_message_append_args (message, |
| DBUS_TYPE_STRING, &name, |
| DBUS_TYPE_UINT32, &flags, |
| DBUS_TYPE_INVALID)) |
| { |
| dbus_message_unref (message); |
| _DBUS_SET_OOM (error); |
| return -1; |
| } |
| |
| reply = dbus_connection_send_with_reply_and_block (connection, message, -1, |
| error); |
| |
| dbus_message_unref (message); |
| |
| if (reply == NULL) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| return -1; |
| } |
| |
| if (dbus_set_error_from_message (error, reply)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| dbus_message_unref (reply); |
| return -1; |
| } |
| |
| if (!dbus_message_get_args (reply, error, |
| DBUS_TYPE_UINT32, &result, |
| DBUS_TYPE_INVALID)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| dbus_message_unref (reply); |
| return -1; |
| } |
| |
| dbus_message_unref (reply); |
| |
| return result; |
| } |
| |
| |
| /** |
| * Asks the bus to unassign the given name from this connection by |
| * invoking the ReleaseName method on the bus. The "ReleaseName" |
| * method is canonically documented in the D-Bus specification. |
| * |
| * Possible results are: #DBUS_RELEASE_NAME_REPLY_RELEASED |
| * which means you owned the name or were in the queue to own it, |
| * and and now you don't own it and aren't in the queue. |
| * #DBUS_RELEASE_NAME_REPLY_NOT_OWNER which means someone else |
| * owns the name so you can't release it. |
| * #DBUS_RELEASE_NAME_REPLY_NON_EXISTENT |
| * which means nobody owned the name. |
| * |
| * @param connection the connection |
| * @param name the name to remove |
| * @param error location to store the error |
| * @returns a result code, -1 if error is set |
| */ |
| int |
| dbus_bus_release_name (DBusConnection *connection, |
| const char *name, |
| DBusError *error) |
| { |
| DBusMessage *message, *reply; |
| dbus_uint32_t result; |
| |
| _dbus_return_val_if_fail (connection != NULL, 0); |
| _dbus_return_val_if_fail (name != NULL, 0); |
| _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), 0); |
| _dbus_return_val_if_error_is_set (error, 0); |
| |
| message = dbus_message_new_method_call (DBUS_SERVICE_DBUS, |
| DBUS_PATH_DBUS, |
| DBUS_INTERFACE_DBUS, |
| "ReleaseName"); |
| |
| if (message == NULL) |
| { |
| _DBUS_SET_OOM (error); |
| return -1; |
| } |
| |
| if (!dbus_message_append_args (message, |
| DBUS_TYPE_STRING, &name, |
| DBUS_TYPE_INVALID)) |
| { |
| dbus_message_unref (message); |
| _DBUS_SET_OOM (error); |
| return -1; |
| } |
| |
| reply = dbus_connection_send_with_reply_and_block (connection, message, -1, |
| error); |
| |
| dbus_message_unref (message); |
| |
| if (reply == NULL) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| return -1; |
| } |
| |
| if (dbus_set_error_from_message (error, reply)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| dbus_message_unref (reply); |
| return -1; |
| } |
| |
| if (!dbus_message_get_args (reply, error, |
| DBUS_TYPE_UINT32, &result, |
| DBUS_TYPE_INVALID)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| dbus_message_unref (reply); |
| return -1; |
| } |
| |
| dbus_message_unref (reply); |
| |
| return result; |
| } |
| |
| /** |
| * Asks the bus whether a certain name has an owner. |
| * |
| * Using this can easily result in a race condition, |
| * since an owner can appear or disappear after you |
| * call this. |
| * |
| * If you want to request a name, just request it; |
| * if you want to avoid replacing a current owner, |
| * don't specify #DBUS_NAME_FLAG_REPLACE_EXISTING and |
| * you will get an error if there's already an owner. |
| * |
| * @param connection the connection |
| * @param name the name |
| * @param error location to store any errors |
| * @returns #TRUE if the name exists, #FALSE if not or on error |
| */ |
| dbus_bool_t |
| dbus_bus_name_has_owner (DBusConnection *connection, |
| const char *name, |
| DBusError *error) |
| { |
| DBusMessage *message, *reply; |
| dbus_bool_t exists; |
| |
| _dbus_return_val_if_fail (connection != NULL, FALSE); |
| _dbus_return_val_if_fail (name != NULL, FALSE); |
| _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE); |
| _dbus_return_val_if_error_is_set (error, FALSE); |
| |
| message = dbus_message_new_method_call (DBUS_SERVICE_DBUS, |
| DBUS_PATH_DBUS, |
| DBUS_INTERFACE_DBUS, |
| "NameHasOwner"); |
| if (message == NULL) |
| { |
| _DBUS_SET_OOM (error); |
| return FALSE; |
| } |
| |
| if (!dbus_message_append_args (message, |
| DBUS_TYPE_STRING, &name, |
| DBUS_TYPE_INVALID)) |
| { |
| dbus_message_unref (message); |
| _DBUS_SET_OOM (error); |
| return FALSE; |
| } |
| |
| reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error); |
| dbus_message_unref (message); |
| |
| if (reply == NULL) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| return FALSE; |
| } |
| |
| if (!dbus_message_get_args (reply, error, |
| DBUS_TYPE_BOOLEAN, &exists, |
| DBUS_TYPE_INVALID)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| dbus_message_unref (reply); |
| return FALSE; |
| } |
| |
| dbus_message_unref (reply); |
| return exists; |
| } |
| |
| /** |
| * Starts a service that will request ownership of the given name. |
| * The returned result will be one of be one of |
| * #DBUS_START_REPLY_SUCCESS or #DBUS_START_REPLY_ALREADY_RUNNING if |
| * successful. Pass #NULL if you don't care about the result. |
| * |
| * The flags parameter is for future expansion, currently you should |
| * specify 0. |
| * |
| * It's often easier to avoid explicitly starting services, and |
| * just send a method call to the service's bus name instead. |
| * Method calls start a service to handle them by default |
| * unless you call dbus_message_set_auto_start() to disable this |
| * behavior. |
| * |
| * @param connection the connection |
| * @param name the name we want the new service to request |
| * @param flags the flags (should always be 0 for now) |
| * @param result a place to store the result or #NULL |
| * @param error location to store any errors |
| * @returns #TRUE if the activation succeeded, #FALSE if not |
| */ |
| dbus_bool_t |
| dbus_bus_start_service_by_name (DBusConnection *connection, |
| const char *name, |
| dbus_uint32_t flags, |
| dbus_uint32_t *result, |
| DBusError *error) |
| { |
| DBusMessage *msg; |
| DBusMessage *reply; |
| |
| _dbus_return_val_if_fail (connection != NULL, FALSE); |
| _dbus_return_val_if_fail (_dbus_check_is_valid_bus_name (name), FALSE); |
| |
| msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS, |
| DBUS_PATH_DBUS, |
| DBUS_INTERFACE_DBUS, |
| "StartServiceByName"); |
| |
| if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &name, |
| DBUS_TYPE_UINT32, &flags, DBUS_TYPE_INVALID)) |
| { |
| dbus_message_unref (msg); |
| _DBUS_SET_OOM (error); |
| return FALSE; |
| } |
| |
| reply = dbus_connection_send_with_reply_and_block (connection, msg, |
| -1, error); |
| dbus_message_unref (msg); |
| |
| if (reply == NULL) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| return FALSE; |
| } |
| |
| if (dbus_set_error_from_message (error, reply)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| dbus_message_unref (reply); |
| return FALSE; |
| } |
| |
| if (result != NULL && |
| !dbus_message_get_args (reply, error, DBUS_TYPE_UINT32, |
| result, DBUS_TYPE_INVALID)) |
| { |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| dbus_message_unref (reply); |
| return FALSE; |
| } |
| |
| dbus_message_unref (reply); |
| return TRUE; |
| } |
| |
| static void |
| send_no_return_values (DBusConnection *connection, |
| DBusMessage *msg, |
| DBusError *error) |
| { |
| if (error) |
| { |
| /* Block to check success codepath */ |
| DBusMessage *reply; |
| |
| reply = dbus_connection_send_with_reply_and_block (connection, msg, |
| -1, error); |
| |
| if (reply == NULL) |
| _DBUS_ASSERT_ERROR_IS_SET (error); |
| else |
| dbus_message_unref (reply); |
| } |
| else |
| { |
| /* Silently-fail nonblocking codepath */ |
| dbus_message_set_no_reply (msg, TRUE); |
| dbus_connection_send (connection, msg, NULL); |
| } |
| } |
| |
| /** |
| * Adds a match rule to match messages going through the message bus. |
| * The "rule" argument is the string form of a match rule. |
| * |
| * If you pass #NULL for the error, this function will not |
| * block; the match thus won't be added until you flush the |
| * connection, and if there's an error adding the match |
| * (only possible error is lack of resources in the bus), |
| * you won't find out about it. |
| * |
| * If you pass non-#NULL for the error this function will |
| * block until it gets a reply. |
| * |
| * Normal API conventions would have the function return |
| * a boolean value indicating whether the error was set, |
| * but that would require blocking always to determine |
| * the return value. |
| * |
| * The AddMatch method is fully documented in the D-Bus |
| * specification. For quick reference, the format of the |
| * match rules is discussed here, but the specification |
| * is the canonical version of this information. |
| * |
| * Rules are specified as a string of comma separated |
| * key/value pairs. An example is |
| * "type='signal',sender='org.freedesktop.DBus', |
| * interface='org.freedesktop.DBus',member='Foo', |
| * path='/bar/foo',destination=':452345.34'" |
| * |
| * Possible keys you can match on are type, sender, |
| * interface, member, path, destination and numbered |
| * keys to match message args (keys are 'arg0', 'arg1', etc.). |
| * Omitting a key from the rule indicates |
| * a wildcard match. For instance omitting |
| * the member from a match rule but adding a sender would |
| * let all messages from that sender through regardless of |
| * the member. |
| * |
| * Matches are inclusive not exclusive so as long as one |
| * rule matches the message will get through. It is important |
| * to note this because every time a message is received the |
| * application will be paged into memory to process it. This |
| * can cause performance problems such as draining batteries |
| * on embedded platforms. |
| * |
| * If you match message args ('arg0', 'arg1', and so forth) |
| * only string arguments will match. That is, arg0='5' means |
| * match the string "5" not the integer 5. |
| * |
| * Currently there is no way to match against non-string arguments. |
| * |
| * A specialised form of wildcard matching on arguments is |
| * supported for path-like namespaces. If your argument match has |
| * a 'path' suffix (eg: "arg0path='/some/path/'") then it is |
| * considered a match if the argument exactly matches the given |
| * string or if one of them ends in a '/' and is a prefix of the |
| * other. |
| * |
| * Matching on interface is tricky because method call |
| * messages only optionally specify the interface. |
| * If a message omits the interface, then it will NOT match |
| * if the rule specifies an interface name. This means match |
| * rules on method calls should not usually give an interface. |
| * |
| * However, signal messages are required to include the interface |
| * so when matching signals usually you should specify the interface |
| * in the match rule. |
| * |
| * For security reasons, you can match arguments only up to |
| * #DBUS_MAXIMUM_MATCH_RULE_ARG_NUMBER. |
| * |
| * Match rules have a maximum length of #DBUS_MAXIMUM_MATCH_RULE_LENGTH |
| * bytes. |
| * |
| * Both of these maximums are much higher than you're likely to need, |
| * they only exist because the D-Bus bus daemon has fixed limits on |
| * all resource usage. |
| * |
| * @param connection connection to the message bus |
| * @param rule textual form of match rule |
| * @param error location to store any errors |
| */ |
| void |
| dbus_bus_add_match (DBusConnection *connection, |
| const char *rule, |
| DBusError *error) |
| { |
| DBusMessage *msg; |
| |
| _dbus_return_if_fail (rule != NULL); |
| |
| msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS, |
| DBUS_PATH_DBUS, |
| DBUS_INTERFACE_DBUS, |
| "AddMatch"); |
| |
| if (msg == NULL) |
| { |
| _DBUS_SET_OOM (error); |
| return; |
| } |
| |
| if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &rule, |
| DBUS_TYPE_INVALID)) |
| { |
| dbus_message_unref (msg); |
| _DBUS_SET_OOM (error); |
| return; |
| } |
| |
| send_no_return_values (connection, msg, error); |
| |
| dbus_message_unref (msg); |
| } |
| |
| /** |
| * Removes a previously-added match rule "by value" (the most |
| * recently-added identical rule gets removed). The "rule" argument |
| * is the string form of a match rule. |
| * |
| * The bus compares match rules semantically, not textually, so |
| * whitespace and ordering don't have to be identical to |
| * the rule you passed to dbus_bus_add_match(). |
| * |
| * If you pass #NULL for the error, this function will not |
| * block; otherwise it will. See detailed explanation in |
| * docs for dbus_bus_add_match(). |
| * |
| * @param connection connection to the message bus |
| * @param rule textual form of match rule |
| * @param error location to store any errors |
| */ |
| void |
| dbus_bus_remove_match (DBusConnection *connection, |
| const char *rule, |
| DBusError *error) |
| { |
| DBusMessage *msg; |
| |
| _dbus_return_if_fail (rule != NULL); |
| |
| msg = dbus_message_new_method_call (DBUS_SERVICE_DBUS, |
| DBUS_PATH_DBUS, |
| DBUS_INTERFACE_DBUS, |
| "RemoveMatch"); |
| |
| if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, &rule, |
| DBUS_TYPE_INVALID)) |
| { |
| dbus_message_unref (msg); |
| _DBUS_SET_OOM (error); |
| return; |
| } |
| |
| send_no_return_values (connection, msg, error); |
| |
| dbus_message_unref (msg); |
| } |
| |
| /** @} */ |
