Do not crash if InputClassifier HAL crashes
If InputClassifier HAL crashes for some reason, we don't have to crash
the system. Instead, just check return type and move on. The
InputClassifier stage is not critical to input dispatch, and the phone
can remain perfectly functional without this stage.
Log an error message instead.
We are also assuming in InputClassifier that HAL is always present.
There are 2 lines of defense here:
1) MotionClassifier always checks the returns from the HAL. If any of
the returns are not OK, then MotionClassifier thread exits. This is safe
to do always, but a downside of this is that logspam will occur if
events are not able to be added to the queue (since the thread that is
to be consuming them is no longer running).
2) Register HAL death recipient in InputClassifier. When the HAL death
occurs, mMotionClassifier will be set to null, thus
preventing further events from going into the queue. This will avoid the
logspam from 1).
Test: ps -A | grep -i input. Then interact with the phone. Then kill the
HAL process, 'killall
android.hardware.input.classifier@1.0-service-example'. Then make sure
that phone remains functional.
Bug: 117935272
Change-Id: I7e8f676d3baa0703198f0731273678c3575bdf60
diff --git a/services/inputflinger/InputClassifier.h b/services/inputflinger/InputClassifier.h
index b97357d..0b1483f 100644
--- a/services/inputflinger/InputClassifier.h
+++ b/services/inputflinger/InputClassifier.h
@@ -69,7 +69,13 @@
* provide a MotionClassification for the current gesture.
*/
virtual MotionClassification classify(const NotifyMotionArgs& args) = 0;
+ /**
+ * Reset all internal HAL state.
+ */
virtual void reset() = 0;
+ /**
+ * Reset HAL state for a specific device.
+ */
virtual void reset(const NotifyDeviceResetArgs& args) = 0;
/**
@@ -107,6 +113,9 @@
*/
class MotionClassifier final : public MotionClassifierInterface {
public:
+ /**
+ * The provided pointer to the service cannot be null.
+ */
MotionClassifier(sp<android::hardware::input::classifier::V1_0::IInputClassifier> service);
~MotionClassifier();
/**
@@ -128,6 +137,10 @@
// The events that need to be sent to the HAL.
BlockingQueue<ClassifierEvent> mEvents;
/**
+ * Add an event to the queue mEvents.
+ */
+ void enqueueEvent(ClassifierEvent&& event);
+ /**
* Thread that will communicate with InputClassifier HAL.
* This should be the only thread that communicates with InputClassifier HAL,
* because this thread is allowed to block on the HAL calls.
@@ -143,9 +156,9 @@
*/
void callInputClassifierHal();
/**
- * Access to the InputClassifier HAL
+ * Access to the InputClassifier HAL. Can always be safely dereferenced.
*/
- sp<android::hardware::input::classifier::V1_0::IInputClassifier> mService;
+ const sp<android::hardware::input::classifier::V1_0::IInputClassifier> mService;
std::mutex mLock;
/**
* Per-device input classifications. Should only be accessed using the
@@ -184,15 +197,19 @@
void requestExit();
};
+
/**
* Implementation of the InputClassifierInterface.
* Represents a separate stage of input processing. All of the input events go through this stage.
* Acts as a passthrough for all input events except for motion events.
* The events of motion type are sent to MotionClassifier.
*/
-class InputClassifier : public InputClassifierInterface {
+class InputClassifier : public InputClassifierInterface,
+ public android::hardware::hidl_death_recipient {
public:
explicit InputClassifier(const sp<InputListenerInterface>& listener);
+ // Some of the constructor logic is finished in onFirstRef
+ virtual void onFirstRef() override;
virtual void notifyConfigurationChanged(const NotifyConfigurationChangedArgs* args) override;
virtual void notifyKey(const NotifyKeyArgs* args) override;
@@ -200,10 +217,15 @@
virtual void notifySwitch(const NotifySwitchArgs* args) override;
virtual void notifyDeviceReset(const NotifyDeviceResetArgs* args) override;
+ virtual void serviceDied(uint64_t cookie,
+ const wp<android::hidl::base::V1_0::IBase>& who) override;
+
virtual void dump(std::string& dump) override;
private:
- std::unique_ptr<MotionClassifierInterface> mMotionClassifier = nullptr;
+ // Protect access to mMotionClassifier, since it may become null via a hidl callback
+ std::mutex mLock;
+ std::unique_ptr<MotionClassifierInterface> mMotionClassifier GUARDED_BY(mLock);
// The next stage to pass input events to
sp<InputListenerInterface> mListener;
};