{
ca_mutex_lock(g_context.lock);
- bool const started = (g_context.event_loop != NULL);
+ bool const started =
+ (g_context.event_loop != NULL
+ && g_main_loop_is_running(g_context.event_loop));
ca_mutex_unlock(g_context.lock);
return success;
}
+/**
+ * Inform thread waiting for the event loop to start that the loop has
+ * started. This is done in the context of the event loop itself so
+ * that we can be certain that the event loop is indeed running.
+ */
+static gboolean CALEEventLoopStarted(gpointer user_data)
+{
+ sem_t * const sem = user_data;
+
+ (void) sem_post(sem);
+
+ return G_SOURCE_REMOVE;
+}
+
static void CALEStartEventLoop(void * data)
{
CALEContext * const context = data;
*/
if (CALESetUpDBus(&g_context))
{
- /*
- Notify the upper LE stack of the availability of Bluetooth
- adapters, if any are already powered on.
- */
- if (CAGetLEAdapterState() == CA_STATUS_OK)
- {
- /**
- * @todo Should we acquire the context lock here to
- * prevent the @c CALEDeviceStateChangedCallback
- * from being potentially yanked out from under us
- * if the CA adapters are stopped/terminated as
- * we're about to invoke this callback?
- */
- g_context.on_device_state_changed(CA_ADAPTER_ENABLED);
- }
-
ca_mutex_lock(context->lock);
assert(context->event_loop == NULL);
ca_mutex_unlock(context->lock);
+ /*
+ Add an idle handler that notifies a thread waiting for the
+ GLib event loop to run that the event loop is actually
+ running. We do this in the context of the event loop itself
+ to avoid race conditions.
+ */
+ GSource * const source = g_idle_source_new();
+ g_source_set_priority(source, G_PRIORITY_HIGH_IDLE);
+ g_source_set_callback(source,
+ CALEEventLoopStarted,
+ &context->le_started, // data
+ NULL); // notify
+ (void) g_source_attach(source, loop_context);
+ g_source_unref(source);
+
g_main_loop_run(event_loop); // Blocks until loop is quit.
+
+ CALETearDownDBus(&g_context);
}
/*
return success;
}
-static CAResult_t CALEStop()
-{
- CAResult_t result = CA_STATUS_FAILED;
-
- OIC_LOG(DEBUG, TAG, "Stop Linux BLE adapter.");
-
- // Only stop if we were previously started.
- if (CALECheckStarted())
- {
- // Stop the event loop thread regardless of previous errors.
- CALEStopEventLoop(&g_context);
- CALETearDownDBus(&g_context);
- result = CA_STATUS_OK;
- }
-
- return result;
-}
-
// -----------------------------------------------------------------------
CAResult_t CAInitializeLEAdapter()
OIC_LOG(DEBUG, TAG, __func__);
+ CAResult_t result = CA_STATUS_FAILED;
+
// Only start if we were previously stopped.
if (CALECheckStarted())
{
- return CA_STATUS_FAILED;
+ return result;
}
/**
* the @c CAGetLEInterfaceInformation() function below for
* further details.
*/
- return ca_thread_pool_add_task(g_context.client_thread_pool,
- CALEStartEventLoop,
- &g_context);
+ result = ca_thread_pool_add_task(g_context.client_thread_pool,
+ CALEStartEventLoop,
+ &g_context);
+
+ /*
+ Wait for the GLib event loop to actually run before returning.
+
+ This addresses corner cases where operations are incorrectly
+ permitted to run in parallel before the event loop is run. For
+ example, the LE transport could have been stopped in a thread
+ parallel to the one starting the event loop start. In that case
+ the GLib event loop may never exit since the stop operation that
+ causes the event loop to exit occurred before event loop
+ started. That ultimately causes the CA layer termination to
+ block indefinitely on a pthread_join(). The solution is to only
+ return from the LE transport start operation once we know the
+ event loop is up and running.
+ */
+ struct timespec abs_timeout;
+ if (result == CA_STATUS_OK
+ && clock_gettime(CLOCK_REALTIME, &abs_timeout) == 0)
+ {
+ static time_t const relative_timeout = 2; // seconds
+ abs_timeout.tv_sec += relative_timeout;
+
+ int const wait_result =
+ sem_timedwait(&g_context.le_started, &abs_timeout);
+
+ if (wait_result == 0)
+ {
+ result = CA_STATUS_OK;
+ }
+ }
+
+ return result;
}
CAResult_t CAStopLEAdapter()
CAUnselectNetwork(CA_ADAPTER_GATT_BTLE) is called by the user.
*/
- OIC_LOG(DEBUG, TAG, __func__);
+ OIC_LOG(DEBUG, TAG, "Stop Linux BLE adapter.");
- return CALEStop();
+ // Only stop if we were previously started.
+ if (!CALECheckStarted())
+ {
+ return CA_STATUS_FAILED;
+ }
+
+ CALEStopEventLoop(&g_context);
+
+ return CA_STATUS_OK;
}
g_context.lock = ca_mutex_new();
g_context.condition = ca_cond_new();
+ static int const PSHARED = 0; // shared between threads
+ static unsigned int const VALUE = 0; // force sem_wait() to block
+
+ if (sem_init(&g_context.le_started, PSHARED, VALUE) != 0)
+ {
+ return CA_STATUS_FAILED;
+ }
+
/*
The CA LE interface doesn't expose a CAInitializeLEGattServer()
function so perform initialization here.
*/
CAPeripheralFinalize();
+ (void) sem_destroy(&g_context.le_started);
+
ca_mutex_lock(g_context.lock);
g_context.on_device_state_changed = NULL;
uint32_t length)
{
/*
- Check if the client has actually started. In some cases, the
- caller may not properly handle the asynchronous initialization
- or check for successful initialization prior to sending out a
- multicast style request.
- */
- if (!CALECheckStarted())
- {
- OIC_LOG(ERROR, TAG, "Client not yet started.");
-
- return CA_STATUS_FAILED;
- }
-
- /*
Now send the request through all BLE connections through the
corresponding OIC GATT request characterstics.
*/
{
ca_mutex_lock(g_context.lock);
- bool const started = (g_context.base != NULL);
+ bool const started =
+ (g_context.event_loop != NULL
+ && g_main_loop_is_running(g_context.event_loop));
ca_mutex_unlock(g_context.lock);
"Lost name \"%s\" on D-Bus!", name);
}
+/**
+ * Inform thread waiting for the event loop to start that the loop has
+ * started. This is done in the context of the event loop itself so
+ * that we can be certain that the event loop is indeed running.
+ */
+static gboolean CAPeripheralEventLoopStarted(gpointer user_data)
+{
+ ca_cond const condition = user_data;
+
+ ca_cond_signal(condition); // For service registration
+
+ return G_SOURCE_REMOVE;
+}
+
static void CAPeripheralStartEventLoop(void * data)
{
CALEContext * const context = data;
ca_mutex_unlock(g_context.lock);
- ca_cond_signal(g_context.condition);
+ /*
+ Add an idle handler that notifies a thread waiting for the
+ GLib event loop to run that the event loop is actually
+ running. We do this in the context of the event loop itself
+ to avoid race conditions.
+ */
+ GSource * const source = g_idle_source_new();
+ g_source_set_priority(source, G_PRIORITY_HIGH_IDLE);
+ g_source_set_callback(source,
+ CAPeripheralEventLoopStarted,
+ g_context.condition, // data
+ NULL); // notify
+ (void) g_source_attach(source, loop_context);
+ g_source_unref(source);
g_main_loop_run(event_loop); // Blocks until loop is quit.
}
/*
- Wait until initialization completes before proceeding to
- service and advertisement registration.
+ Wait until initialization completes and the event loop is up and
+ running before proceeding to service and advertisement
+ registration.
*/
// Number of times to wait for initialization to complete.
// Only stop if we were previously started.
if (!CAPeripheralCheckStarted())
{
- result = CA_STATUS_OK;
return result;
}
projects / contrib / iotivity.git / commitdiff