/* -*- mode: C; c-file-style: "gnu" -*- */ /* 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 1.2 * * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include "dbus-bus.h" #include "dbus-protocol.h" #include "dbus-internals.h" #include "dbus-message.h" #include /** * @defgroup DBusBus Message bus APIs * @ingroup DBus * @brief Functions for communicating with the message bus * * @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. * * * @todo get rid of most of these; they should be done * with DBusGProxy and the Qt equivalent, i.e. the same * way any other interface would be used. */ typedef struct { DBusConnection *connection; /**< Connection we're associated with */ char *base_service; /**< Base service 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_ACTIVATION; static dbus_bool_t initialized = FALSE; /** * Lock for globals in this file */ _DBUS_DEFINE_GLOBAL_LOCK (bus); static void addresses_shutdown_func (void *data) { int i; i = 0; while (i < N_BUS_TYPES) { if (bus_connections[i] != NULL) _dbus_warn ("dbus_shutdown() called but connections were still live!"); dbus_free (bus_connection_addresses[i]); bus_connection_addresses[i] = NULL; ++i; } activation_bus_type = DBUS_BUS_ACTIVATION; } 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_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 (!get_from_env (&bus_connection_addresses[DBUS_BUS_SESSION], "DBUS_SESSION_BUS_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_ACTIVATION] == NULL) { _dbus_verbose ("Filling in activation bus address...\n"); if (!get_from_env (&bus_connection_addresses[DBUS_BUS_ACTIVATION], "DBUS_ACTIVATION_ADDRESS")) return FALSE; _dbus_verbose (" \"%s\"\n", bus_connection_addresses[DBUS_BUS_ACTIVATION] ? bus_connection_addresses[DBUS_BUS_ACTIVATION] : "none set"); } if (bus_connection_addresses[DBUS_BUS_ACTIVATION] != NULL) { s = _dbus_getenv ("DBUS_ACTIVATION_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_ACTIVATION] = _dbus_strdup (bus_connection_addresses[DBUS_BUS_SESSION]); if (bus_connection_addresses[DBUS_BUS_ACTIVATION] == 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 */ i = 0; while (i < N_BUS_TYPES) { if (bus_connections[i] == bd->connection) bus_connections[i] = NULL; ++i; } _DBUS_UNLOCK (bus); } dbus_free (bd->base_service); 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; } /** @} */ /* 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. * * @todo alex thinks we should nullify the connection when we get a disconnect-message. * * @param type bus type * @param error address where an error can be returned. * @returns a DBusConnection */ DBusConnection * dbus_bus_get (DBusBusType type, 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_error (error, DBUS_ERROR_NO_MEMORY, NULL); 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_ACTIVATION) */ if (type == DBUS_BUS_ACTIVATION && bus_connection_addresses[activation_bus_type] != NULL) type = activation_bus_type; if (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"); _DBUS_UNLOCK (bus); return NULL; } connection = dbus_connection_open (address, error); if (!connection) { _DBUS_ASSERT_ERROR_IS_SET (error); _DBUS_UNLOCK (bus); return NULL; } /* By default we're bound to the lifecycle of * the message bus. */ dbus_connection_set_exit_on_disconnect (connection, TRUE); if (!dbus_bus_register (connection, error)) { _DBUS_ASSERT_ERROR_IS_SET (error); dbus_connection_disconnect (connection); dbus_connection_unref (connection); _DBUS_UNLOCK (bus); return NULL; } bus_connections[type] = connection; bd = ensure_bus_data (connection); _dbus_assert (bd != NULL); bd->is_well_known = TRUE; _DBUS_UNLOCK (bus); return connection; } /** * 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 base service name will be set, * and can be obtained using dbus_bus_get_base_service(). * * @todo if we get an error reply, it has to be converted into * DBusError and returned * * @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; bd = ensure_bus_data (connection); if (bd == NULL) { _DBUS_SET_OOM (error); return FALSE; } if (bd->base_service != NULL) { _dbus_warn ("Attempt to register the same DBusConnection with the message bus, but it is already registered\n"); /* This isn't an error, it's a programming bug. We'll be nice * and not _dbus_assert_not_reached() */ return TRUE; } message = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS, DBUS_PATH_ORG_FREEDESKTOP_DBUS, DBUS_INTERFACE_ORG_FREEDESKTOP_DBUS, "Hello"); if (!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) 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->base_service = name; retval = TRUE; out: if (reply) dbus_message_unref (reply); if (!retval) _DBUS_ASSERT_ERROR_IS_SET (error); return retval; } /** * Sets the base service name of the connection. * 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. * * @param connection the connection * @param base_service the base service name * @returns #FALSE if not enough memory */ dbus_bool_t dbus_bus_set_base_service (DBusConnection *connection, const char *base_service) { BusData *bd; _dbus_return_val_if_fail (connection != NULL, FALSE); _dbus_return_val_if_fail (base_service != NULL, FALSE); bd = ensure_bus_data (connection); if (bd == NULL) return FALSE; _dbus_assert (bd->base_service == NULL); bd->base_service = _dbus_strdup (base_service); return bd->base_service != NULL; } /** * Gets the base service name of the connection. * Only possible after the connection has been registered * with the message bus. * * @param connection the connection * @returns the base service name */ const char* dbus_bus_get_base_service (DBusConnection *connection) { BusData *bd; _dbus_return_val_if_fail (connection != NULL, NULL); bd = ensure_bus_data (connection); if (bd == NULL) return NULL; return bd->base_service; } /** * Asks the bus to try to acquire a certain service. * * @todo these docs are not complete, need to document the * return value and flags * * @todo if we get an error reply, it has to be converted into * DBusError and returned * * @param connection the connection * @param service_name the service name * @param flags flags * @param error location to store the error * @returns a result code, -1 if error is set */ int dbus_bus_acquire_service (DBusConnection *connection, const char *service_name, unsigned int flags, DBusError *error) { DBusMessage *message, *reply; dbus_uint32_t service_result; _dbus_return_val_if_fail (connection != NULL, 0); _dbus_return_val_if_fail (service_name != NULL, 0); _dbus_return_val_if_error_is_set (error, 0); message = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS, DBUS_PATH_ORG_FREEDESKTOP_DBUS, DBUS_INTERFACE_ORG_FREEDESKTOP_DBUS, "AcquireService"); if (message == NULL) { _DBUS_SET_OOM (error); return -1; } if (!dbus_message_append_args (message, DBUS_TYPE_STRING, service_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, &service_result, DBUS_TYPE_INVALID)) { _DBUS_ASSERT_ERROR_IS_SET (error); dbus_message_unref (reply); return -1; } dbus_message_unref (reply); return service_result; } /** * Checks whether a certain service exists. * * @todo the SERVICE_EXISTS message should use BOOLEAN not UINT32 * * @param connection the connection * @param service_name the service name * @param error location to store any errors * @returns #TRUE if the service exists, #FALSE if not or on error */ dbus_bool_t dbus_bus_service_exists (DBusConnection *connection, const char *service_name, DBusError *error) { DBusMessage *message, *reply; unsigned int exists; _dbus_return_val_if_fail (connection != NULL, FALSE); _dbus_return_val_if_fail (service_name != NULL, FALSE); _dbus_return_val_if_error_is_set (error, FALSE); message = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS, DBUS_PATH_ORG_FREEDESKTOP_DBUS, DBUS_INTERFACE_ORG_FREEDESKTOP_DBUS, "ServiceExists"); if (message == NULL) { _DBUS_SET_OOM (error); return FALSE; } if (!dbus_message_append_args (message, DBUS_TYPE_STRING, service_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_UINT32, &exists, DBUS_TYPE_INVALID)) { _DBUS_ASSERT_ERROR_IS_SET (error); return FALSE; } return (exists != FALSE); } /** * Activates a given service * * @param connection the connection * @param service_name the service name * @param flags the flags * @param result a place to store the result of the activation, which will * be one of DBUS_ACTIVATION_REPLY_ACTIVATED or * DBUS_ACTIVATION_REPLY_ALREADY_ACTIVE if successful. Pass NULL if you * don't care about the result. * @param error location to store any errors * @returns #TRUE if the activation succeeded, #FALSE if not * * @todo document what the flags do */ dbus_bool_t dbus_bus_activate_service (DBusConnection *connection, const char *service_name, dbus_uint32_t flags, dbus_uint32_t *result, DBusError *error) { DBusMessage *msg; DBusMessage *reply; msg = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS, DBUS_PATH_ORG_FREEDESKTOP_DBUS, DBUS_INTERFACE_ORG_FREEDESKTOP_DBUS, "ActivateService"); if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, service_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); return; } if (dbus_set_error_from_message (error, reply)) { _DBUS_ASSERT_ERROR_IS_SET (error); dbus_message_unref (reply); return; } dbus_message_unref (reply); } else { /* Silently-fail nonblocking codepath */ if (!dbus_connection_send (connection, msg, NULL)) return; } } /** * 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. * * @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; msg = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS, DBUS_PATH_ORG_FREEDESKTOP_DBUS, DBUS_INTERFACE_ORG_FREEDESKTOP_DBUS, "AddMatch"); 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. * * 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; msg = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS, DBUS_PATH_ORG_FREEDESKTOP_DBUS, DBUS_INTERFACE_ORG_FREEDESKTOP_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); } /** @} */