* @ingroup DBus
* @brief Functions for communicating with the message bus
*
+ */
+
+
+/**
+ * @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
+{
+ char *base_service; /**< Base service name of this connection */
+
+ DBusConnection **connection; /**< Pointer to bus_connections entry */
+} BusData;
+
+/** The slot we have reserved to store BusData
+ */
+static int bus_data_slot = -1;
+/** Number of connections using the slot
+ */
+static int bus_data_slot_refcount = 0;
+
+/**
+ * Lock for bus_data_slot and bus_data_slot_refcount
+ */
+_DBUS_DEFINE_GLOBAL_LOCK (bus);
+
+
+static dbus_bool_t
+data_slot_ref (void)
+{
+ _DBUS_LOCK (bus);
+
+ if (bus_data_slot < 0)
+ {
+ bus_data_slot = dbus_connection_allocate_data_slot ();
+
+ if (bus_data_slot < 0)
+ {
+ _DBUS_UNLOCK (bus);
+ return FALSE;
+ }
+
+ _dbus_assert (bus_data_slot_refcount == 0);
+ }
+
+ bus_data_slot_refcount += 1;
+
+ _DBUS_UNLOCK (bus);
+
+ return TRUE;
+}
+
+static void
+data_slot_unref (void)
+{
+ _DBUS_LOCK (bus);
+
+ _dbus_assert (bus_data_slot_refcount > 0);
+ _dbus_assert (bus_data_slot >= 0);
+
+ bus_data_slot_refcount -= 1;
+
+ if (bus_data_slot_refcount == 0)
+ {
+ dbus_connection_free_data_slot (bus_data_slot);
+ bus_data_slot = -1;
+ }
+
+ _DBUS_UNLOCK (bus);
+}
+
+static void
+bus_data_free (void *data)
+{
+ BusData *bd = data;
+
+ if (bd->connection)
+ {
+ _DBUS_LOCK (bus);
+ *bd->connection = NULL;
+ _DBUS_UNLOCK (bus);
+ }
+
+ dbus_free (bd->base_service);
+ dbus_free (bd);
+
+ data_slot_unref ();
+}
+
+static BusData*
+ensure_bus_data (DBusConnection *connection)
+{
+ BusData *bd;
+
+ if (!data_slot_ref ())
+ return NULL;
+
+ bd = dbus_connection_get_data (connection, bus_data_slot);
+ if (bd == NULL)
+ {
+ bd = dbus_new0 (BusData, 1);
+ if (bd == NULL)
+ {
+ data_slot_unref ();
+ return NULL;
+ }
+
+ if (!dbus_connection_set_data (connection, bus_data_slot, bd,
+ bus_data_free))
+ {
+ dbus_free (bd);
+ data_slot_unref ();
+ return NULL;
+ }
+
+ /* Data slot refcount now held by the BusData */
+ }
+ else
+ {
+ data_slot_unref ();
+ }
+
+ return bd;
+}
+
+/** @} */ /* end of implementation details docs */
+
+/**
+ * @addtogroup DBusBus
* @{
*/
+/** Number of bus types */
+#define BUS_TYPES 2
+
+static DBusConnection *bus_connections[BUS_TYPES];
+
+/**
+ * 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 *name, *value;
+ DBusConnection *connection;
+ BusData *bd;
+
+ if (type <= 0 || type >= BUS_TYPES)
+ {
+ _dbus_assert_not_reached ("Invalid bus type specified.");
+
+ return NULL;
+ }
+
+ _DBUS_LOCK (bus);
+
+ if (bus_connections[type] != NULL)
+ {
+ connection = bus_connections[type];
+ dbus_connection_ref (connection);
+
+ _DBUS_UNLOCK (bus);
+ return connection;
+ }
+
+ switch (type)
+ {
+ case DBUS_BUS_SESSION:
+ name = "DBUS_SESSION_BUS_ADDRESS";
+ break;
+ case DBUS_BUS_SYSTEM:
+ name = "DBUS_SYSTEM_BUS_ADDRESS";
+ break;
+ }
+
+ value = _dbus_getenv (name);
+
+ if (type == DBUS_BUS_SYSTEM &&
+ (value == NULL || *value == '\0'))
+ {
+ /* Use default system bus address if none set */
+ value = "unix:path=" DBUS_SYSTEM_BUS_PATH;
+ }
+
+ if (value == NULL || *value == '\0')
+ {
+ dbus_set_error (error, DBUS_ERROR_FAILED,
+ "Environment variable %s not set, address of message bus unknown",
+ name);
+ _DBUS_UNLOCK (bus);
+
+ return NULL;
+ }
+
+ connection = dbus_connection_open (value, error);
+
+ if (!connection)
+ {
+ _DBUS_UNLOCK (bus);
+ return NULL;
+ }
+
+ if (!dbus_bus_register (connection, 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->connection = &bus_connections[type];
+
+ _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 the client's unique service name, #NULL on error
+ * @returns #TRUE on success
*/
-char*
-dbus_bus_register_client (DBusConnection *connection,
- DBusError *error)
+dbus_bool_t
+dbus_bus_register (DBusConnection *connection,
+ DBusError *error)
{
DBusMessage *message, *reply;
char *name;
+ BusData *bd;
+
+ _DBUS_ASSERT_ERROR_IS_CLEAR (error);
+
+ 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 (DBUS_SERVICE_DBUS,
DBUS_MESSAGE_HELLO);
if (!message)
{
_DBUS_SET_OOM (error);
- return NULL;
+ return FALSE;
}
reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
if (reply == NULL)
{
_DBUS_ASSERT_ERROR_IS_SET (error);
- return NULL;
+ return FALSE;
}
if (!dbus_message_get_args (reply, error,
0))
{
_DBUS_ASSERT_ERROR_IS_SET (error);
- return NULL;
+ return FALSE;
}
+
+ bd->base_service = name;
- return name;
+ return TRUE;
+}
+
+
+/**
+ * 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;
+
+ bd = ensure_bus_data (connection);
+ if (bd == NULL)
+ return FALSE;
+
+ _dbus_assert (bd->base_service == NULL);
+ _dbus_assert (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;
+
+ bd = ensure_bus_data (connection);
+ if (bd == NULL)
+ return NULL;
+
+ return bd->base_service;
}
/**
{
DBusMessage *message, *reply;
unsigned int exists;
+
+ _DBUS_ASSERT_ERROR_IS_CLEAR (error);
message = dbus_message_new (DBUS_SERVICE_DBUS,
DBUS_MESSAGE_SERVICE_EXISTS);
projects / platform / upstream / dbus.git / blobdiff