/* Flags in connection->atomic_flags */
enum {
- FLAG_INITIALIZED = 1 << 0
+ FLAG_INITIALIZED = 1 << 0,
+ FLAG_EXIT_ON_CLOSE = 1 << 1,
+ FLAG_CLOSED = 1 << 2
};
/**
/* -- General object state ------------------------------------------------ */
/* ------------------------------------------------------------------------ */
- /* object-wide lock */
+ /* General-purpose lock for most fields */
GMutex lock;
/* A lock used in the init() method of the GInitable interface - see comments
- * in initable_init() for why a separate lock is needed
+ * in initable_init() for why a separate lock is needed.
+ *
+ * If you need both @lock and @init_lock, you must take @init_lock first.
*/
GMutex init_lock;
/* Set (by loading the contents of /var/lib/dbus/machine-id) the first time
- * someone calls org.freedesktop.DBus.GetMachineId()
+ * someone calls org.freedesktop.DBus.GetMachineId(). Protected by @lock.
*/
gchar *machine_id;
*/
GDBusAuth *auth;
- /* Set to TRUE if the connection has been closed */
- gboolean closed;
-
- /* Last serial used */
+ /* Last serial used. Protected by @lock. */
guint32 last_serial;
/* The object used to send/receive messages.
/* FLAG_INITIALIZED is set exactly when initable_init() has finished running.
* Inspect @initialization_error to see whether it succeeded or failed.
+ *
+ * FLAG_EXIT_ON_CLOSE is the exit-on-close property.
+ *
+ * FLAG_CLOSED is the closed property. It may be read at any time, but
+ * may only be written while holding @lock.
*/
volatile gint atomic_flags;
/* The result of g_main_context_ref_thread_default() when the object
* was created (the GObject _init() function) - this is used for delivery
* of the :closed GObject signal.
+ *
+ * Only set in the GObject init function, so no locks are needed.
*/
GMainContext *main_context_at_construction;
- /* construct properties */
+ /* Read-only construct properties, no locks needed */
gchar *address;
GDBusConnectionFlags flags;
- /* Map used for managing method replies */
+ /* Map used for managing method replies, protected by @lock */
GHashTable *map_method_serial_to_send_message_data; /* guint32 -> SendMessageData* */
- /* Maps used for managing signal subscription */
+ /* Maps used for managing signal subscription, protected by @lock */
GHashTable *map_rule_to_signal_data; /* match rule (gchar*) -> SignalData */
GHashTable *map_id_to_signal_data; /* id (guint) -> SignalData */
GHashTable *map_sender_unique_name_to_signal_data_array; /* unique sender (gchar*) -> GPtrArray* of SignalData */
- /* Maps used for managing exported objects and subtrees */
+ /* Maps used for managing exported objects and subtrees,
+ * protected by @lock
+ */
GHashTable *map_object_path_to_eo; /* gchar* -> ExportedObject* */
GHashTable *map_id_to_ei; /* guint -> ExportedInterface* */
GHashTable *map_object_path_to_es; /* gchar* -> ExportedSubtree* */
GHashTable *map_id_to_es; /* guint -> ExportedSubtree* */
- /* Structure used for message filters */
+ /* Structure used for message filters, protected by @lock */
GPtrArray *filters;
- /* Whether to exit on close */
- gboolean exit_on_close;
-
/* Capabilities negotiated during authentication
* Read-only after initable_init(), so it may be read without holding a
* lock, if you check for initialization first.
*/
GDBusCapabilityFlags capabilities;
+ /* Protected by @init_lock */
GDBusAuthObserver *authentication_observer;
/* Read-only after initable_init(), so it may be read if you either
return TRUE;
}
+typedef enum {
+ MAY_BE_UNINITIALIZED = (1<<1)
+} CheckUnclosedFlags;
+
+/*
+ * Check the same thing as check_initialized(), and also that the
+ * connection is not closed. If the connection is uninitialized,
+ * raise a critical warning (it's programmer error); if it's closed,
+ * raise a recoverable GError (it's a runtime error).
+ *
+ * This function is a memory barrier.
+ *
+ * Returns: %TRUE if initialized and not closed
+ */
+static gboolean
+check_unclosed (GDBusConnection *connection,
+ CheckUnclosedFlags check,
+ GError **error)
+{
+ /* check_initialized() is effectively inlined, so we don't waste time
+ * doing two memory barriers
+ */
+ gint flags = g_atomic_int_get (&connection->atomic_flags);
+
+ if (!(check & MAY_BE_UNINITIALIZED))
+ {
+ g_return_val_if_fail (flags & FLAG_INITIALIZED, FALSE);
+ g_return_val_if_fail (connection->initialization_error == NULL, FALSE);
+ }
+
+ if (flags & FLAG_CLOSED)
+ {
+ g_set_error_literal (error,
+ G_IO_ERROR,
+ G_IO_ERROR_CLOSED,
+ _("The connection is closed"));
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
static GHashTable *alive_connections = NULL;
static void
/* Because atomic int access is a memory barrier, we can safely read
* initialization_error without a lock, as long as we do it afterwards.
*/
- if (remote_peer_vanished && connection->exit_on_close &&
+ if (remote_peer_vanished &&
+ (flags & FLAG_EXIT_ON_CLOSE) != 0 &&
(flags & FLAG_INITIALIZED) != 0 &&
connection->initialization_error == NULL)
{
gboolean
g_dbus_connection_is_closed (GDBusConnection *connection)
{
+ gint flags;
+
g_return_val_if_fail (G_IS_DBUS_CONNECTION (connection), FALSE);
- return connection->closed;
+
+ flags = g_atomic_int_get (&connection->atomic_flags);
+
+ return (flags & FLAG_CLOSED) ? TRUE : FALSE;
}
/**
ret = FALSE;
- /* do not use g_return_val_if_fail(), we want the memory barrier */
- if (!check_initialized (connection))
+ /* This is only a best-effort attempt to see whether the connection is
+ * closed, so it doesn't need the lock. If the connection closes just
+ * after this check, but before scheduling the flush operation, the
+ * result will be more or less the same as if the connection closed while
+ * the flush operation was pending - it'll fail with either CLOSED or
+ * CANCELLED.
+ */
+ if (!check_unclosed (connection, 0, error))
goto out;
g_assert (connection->worker != NULL);
- if (connection->closed)
- {
- g_set_error_literal (error,
- G_IO_ERROR,
- G_IO_ERROR_CLOSED,
- _("The connection is closed"));
- goto out;
- }
-
ret = _g_dbus_worker_flush_sync (connection->worker,
cancellable,
error);
return FALSE;
}
-/* Can be called from any thread, must hold lock */
+/* Can be called from any thread, must hold lock.
+ * FLAG_CLOSED must already have been set.
+ */
static void
-set_closed_unlocked (GDBusConnection *connection,
- gboolean remote_peer_vanished,
- GError *error)
+schedule_closed_unlocked (GDBusConnection *connection,
+ gboolean remote_peer_vanished,
+ GError *error)
{
GSource *idle_source;
EmitClosedData *data;
CONNECTION_ENSURE_LOCK (connection);
- g_assert (!connection->closed);
-
- connection->closed = TRUE;
-
data = g_new0 (EmitClosedData, 1);
data->connection = g_object_ref (connection);
data->remote_peer_vanished = remote_peer_vanished;
ret = FALSE;
- CONNECTION_LOCK (connection);
- if (!connection->closed)
+ if (check_unclosed (connection, 0, error))
{
GMainContext *context;
SyncCloseData data;
data.loop = g_main_loop_new (context, TRUE);
data.result = NULL;
- CONNECTION_UNLOCK (connection);
g_dbus_connection_close (connection, cancellable, sync_close_cb, &data);
g_main_loop_run (data.loop);
ret = g_dbus_connection_close_finish (connection, data.result, error);
- CONNECTION_LOCK (connection);
g_object_unref (data.result);
g_main_loop_unref (data.loop);
g_main_context_pop_thread_default (context);
g_main_context_unref (context);
}
- else
- {
- g_set_error_literal (error,
- G_IO_ERROR,
- G_IO_ERROR_CLOSED,
- _("The connection is closed"));
- }
- CONNECTION_UNLOCK (connection);
return ret;
}
* chicken-and-egg problems. initable_init() is responsible for setting up
* our prerequisites (mainly connection->worker), and only calling us
* from its own thread (so no memory barrier is needed).
- *
- * In the case where we're not initializing, do not use
- * g_return_val_if_fail() - we want the memory barrier.
*/
- if ((flags & SEND_MESSAGE_FLAGS_INITIALIZING) == 0 &&
- !check_initialized (connection))
+ if (!check_unclosed (connection,
+ (flags & SEND_MESSAGE_FLAGS_INITIALIZING) ? MAY_BE_UNINITIALIZED : 0,
+ error))
goto out;
- if (connection->closed)
- {
- g_set_error_literal (error,
- G_IO_ERROR,
- G_IO_ERROR_CLOSED,
- _("The connection is closed"));
- goto out;
- }
-
blob = g_dbus_message_to_blob (message,
&blob_size,
connection->capabilities,
goto out;
}
- if (connection->closed)
- {
- g_simple_async_result_set_error (simple,
- G_IO_ERROR,
- G_IO_ERROR_CLOSED,
- _("The connection is closed"));
- g_simple_async_result_complete_in_idle (simple);
- g_object_unref (simple);
- goto out;
- }
-
error = NULL;
if (!g_dbus_connection_send_message_unlocked (connection, message, flags, out_serial, &error))
{
{
GDBusConnection *connection;
gboolean alive;
+ guint old_atomic_flags;
G_LOCK (message_bus_lock);
alive = (g_hash_table_lookup (alive_connections, user_data) != NULL);
//g_debug ("in on_worker_closed: %s", error->message);
CONNECTION_LOCK (connection);
- if (!connection->closed)
+ /* Even though this is atomic, we do it inside the lock to avoid breaking
+ * assumptions in remove_match_rule(). We'd need the lock in a moment
+ * anyway, so, no loss.
+ */
+ old_atomic_flags = g_atomic_int_or (&connection->atomic_flags, FLAG_CLOSED);
+
+ if (!(old_atomic_flags & FLAG_CLOSED))
{
g_hash_table_foreach_remove (connection->map_method_serial_to_send_message_data, cancel_method_on_close, NULL);
- set_closed_unlocked (connection, remote_peer_vanished, error);
+ schedule_closed_unlocked (connection, remote_peer_vanished, error);
}
CONNECTION_UNLOCK (connection);
gboolean exit_on_close)
{
g_return_if_fail (G_IS_DBUS_CONNECTION (connection));
- connection->exit_on_close = exit_on_close;
+
+ if (exit_on_close)
+ g_atomic_int_or (&connection->atomic_flags, FLAG_EXIT_ON_CLOSE);
+ else
+ g_atomic_int_and (&connection->atomic_flags, ~FLAG_EXIT_ON_CLOSE);
+
}
/**
g_dbus_connection_get_exit_on_close (GDBusConnection *connection)
{
g_return_val_if_fail (G_IS_DBUS_CONNECTION (connection), FALSE);
- return connection->exit_on_close;
+
+ if (g_atomic_int_get (&connection->atomic_flags) & FLAG_EXIT_ON_CLOSE)
+ return TRUE;
+ else
+ return FALSE;
}
/**
NULL,
&error))
{
+ /* If we could get G_IO_ERROR_CLOSED here, it wouldn't be reasonable to
+ * critical; but we're holding the lock, and our caller checked whether
+ * we were already closed, so we can't get that error.
+ */
g_critical ("Error while sending RemoveMatch() message: %s", error->message);
g_error_free (error);
}
}
/* remove the match rule from the bus unless NameLost or NameAcquired (see subscribe()) */
- if (connection->flags & G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION)
+ if ((connection->flags & G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION) &&
+ !is_signal_data_for_name_lost_or_acquired (signal_data) &&
+ !g_dbus_connection_is_closed (connection) &&
+ !connection->finalizing)
{
- if (!is_signal_data_for_name_lost_or_acquired (signal_data))
- if (!connection->closed && !connection->finalizing)
- remove_match_rule (connection, signal_data->rule);
+ /* The check for g_dbus_connection_is_closed() means that
+ * sending the RemoveMatch message can't fail with
+ * G_IO_ERROR_CLOSED, because we're holding the lock,
+ * so on_worker_closed() can't happen between the check we just
+ * did, and releasing the lock later.
+ */
+ remove_match_rule (connection, signal_data->rule);
}
+
signal_data_free (signal_data);
}
projects / platform / upstream / glib.git / blobdiff