Configure handwriting window with the IME's pid and uid for ANRs

When starting a handwriting session, update the handwriting input window
so that it is configured with the IME's pid and uid. This means any ANRs
that occur due to the handwriting input window will be directed to the
IME process.

Since oneway binder calls do not have pid information, we cannot use
Binder.getCallingPid() to get the pid of the IME. Instead, we report the
pid from IMS when starting handwriting.

Bug: 210978621
Test: manual with custom IME, verify ANR is directed to IME.
Change-Id: Ia6963eb02cad22c7f604896e6c78ed31c84e32f6

core/java/android/inputmethodservice/InputMethodService.java

@@ -83,6 +83,7 @@ import android.os.Bundle;
 import android.os.Handler;
 import android.os.IBinder;
 import android.os.Looper;
+import android.os.Process;
 import android.os.ResultReceiver;
 import android.os.SystemClock;
 import android.os.SystemProperties;
@@ -926,7 +927,7 @@ public class InputMethodService extends AbstractInputMethodService {
                 mOnPreparedStylusHwCalled = true;
             }
             if (onStartStylusHandwriting()) {
-                mPrivOps.onStylusHandwritingReady(requestId);
+                mPrivOps.onStylusHandwritingReady(requestId, Process.myPid());
             } else {
                 Log.i(TAG, "IME is not ready. Can't start Stylus Handwriting");
                 // TODO(b/210039666): see if it's valuable to propagate this back to IMM.

core/java/com/android/internal/inputmethod/IInputMethodPrivilegedOperations.aidl

@@ -42,6 +42,6 @@ oneway interface IInputMethodPrivilegedOperations {
     void shouldOfferSwitchingToNextInputMethod(in AndroidFuture future /* T=Boolean */);
     void notifyUserActionAsync();
     void applyImeVisibilityAsync(IBinder showOrHideInputToken, boolean setVisible);
-    void onStylusHandwritingReady(int requestId);
+    void onStylusHandwritingReady(int requestId, int pid);
     void finishStylusHandwriting(int requestId);
 }

core/java/com/android/internal/inputmethod/InputMethodPrivilegedOperations.java

@@ -396,16 +396,16 @@ public final class InputMethodPrivilegedOperations {
     }
 
     /**
-     * Calls {@link IInputMethodPrivilegedOperations#onStylusHandwritingReady()}
+     * Calls {@link IInputMethodPrivilegedOperations#onStylusHandwritingReady(int, int)}
      */
     @AnyThread
-    public void onStylusHandwritingReady(int requestId) {
+    public void onStylusHandwritingReady(int requestId, int pid) {
         final IInputMethodPrivilegedOperations ops = mOps.getAndWarnIfNull();
         if (ops == null) {
             return;
         }
         try {
-            ops.onStylusHandwritingReady(requestId);
+            ops.onStylusHandwritingReady(requestId, pid);
         } catch (RemoteException e) {
             throw e.rethrowFromSystemServer();
         }

services/core/java/com/android/server/inputmethod/HandwritingEventReceiverSurface.java

@@ -82,13 +82,14 @@ final class HandwritingEventReceiverSurface {
         mIsIntercepting = false;
     }
 
-    void startIntercepting() {
-        // TODO(b/210978621): Update the spy window's PID and UID to be associated with the IME so
-        //  that ANRs are correctly attributed to the IME.
-        final SurfaceControl.Transaction t = new SurfaceControl.Transaction();
+    void startIntercepting(int imePid, int imeUid) {
+        mWindowHandle.ownerPid = imePid;
+        mWindowHandle.ownerUid = imeUid;
         mWindowHandle.inputFeatures &= ~WindowManager.LayoutParams.INPUT_FEATURE_SPY;
-        t.setInputWindowInfo(mInputSurface, mWindowHandle);
-        t.apply();
+
+        new SurfaceControl.Transaction()
+                .setInputWindowInfo(mInputSurface, mWindowHandle)
+                .apply();
         mIsIntercepting = true;
     }
 

services/core/java/com/android/server/inputmethod/HandwritingModeController.java

@@ -136,7 +136,7 @@ final class HandwritingModeController {
      */
     @UiThread
     @Nullable
-    HandwritingSession startHandwritingSession(int requestId) {
+    HandwritingSession startHandwritingSession(int requestId, int imePid, int imeUid) {
         if (mHandwritingSurface == null) {
             Slog.e(TAG, "Cannot start handwriting session: Handwriting was not initialized.");
             return null;
@@ -160,7 +160,7 @@ final class HandwritingModeController {
             throw new IllegalStateException(
                     "Handwriting surface should not be already intercepting.");
         }
-        mHandwritingSurface.startIntercepting();
+        mHandwritingSurface.startIntercepting(imePid, imeUid);
 
         return new HandwritingSession(mCurrentRequestId, mHandwritingSurface.getInputChannel(),
                 mHandwritingBuffer);

services/core/java/com/android/server/inputmethod/InputMethodManagerService.java

@@ -4697,7 +4697,10 @@ public final class InputMethodManagerService extends IInputMethodManager.Stub
                         return true;
                     }
                     final HandwritingModeController.HandwritingSession session =
-                            mHwController.startHandwritingSession(msg.arg1);
+                            mHwController.startHandwritingSession(
+                                    msg.arg1 /*requestId*/,
+                                    msg.arg2 /*pid*/,
+                                    mBindingController.getCurMethodUid());
                     if (session == null) {
                         Slog.e(TAG,
                                 "Failed to start handwriting session for requestId: " + msg.arg1);
@@ -4717,8 +4720,8 @@ public final class InputMethodManagerService extends IInputMethodManager.Stub
     }
 
     @BinderThread
-    private void onStylusHandwritingReady(int requestId) {
-        mHandler.obtainMessage(MSG_START_HANDWRITING, requestId, 0 /* unused */).sendToTarget();
+    private void onStylusHandwritingReady(int requestId, int pid) {
+        mHandler.obtainMessage(MSG_START_HANDWRITING, requestId, pid).sendToTarget();
     }
 
     private void handleSetInteractive(final boolean interactive) {
@@ -6304,8 +6307,8 @@ public final class InputMethodManagerService extends IInputMethodManager.Stub
 
         @BinderThread
         @Override
-        public void onStylusHandwritingReady(int requestId) {
-            mImms.onStylusHandwritingReady(requestId);
+        public void onStylusHandwritingReady(int requestId, int pid) {
+            mImms.onStylusHandwritingReady(requestId, pid);
         }
 
         @BinderThread