4/n: Add and use Face AIDL start/stop user clients

Bug: 181984005
Test: atest CtsBiometricsTestCases
Test: atest com.android.server.biometrics
Change-Id: I1b62b12d3b99fd572450316168b6cea2c7a06e16

services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceProvider.java

@@ -78,7 +78,6 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
     @NonNull private final String mHalInstanceName;
     @NonNull @VisibleForTesting
     final SparseArray<Sensor> mSensors; // Map of sensors that this HAL supports
-    @NonNull private final HalClientMonitor.LazyDaemon<IFace> mLazyDaemon;
     @NonNull private final Handler mHandler;
     @NonNull private final LockoutResetDispatcher mLockoutResetDispatcher;
     @NonNull private final UsageStats mUsageStats;
@@ -126,7 +125,6 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
         mContext = context;
         mHalInstanceName = halInstanceName;
         mSensors = new SparseArray<>();
-        mLazyDaemon = this::getHalInstance;
         mHandler = new Handler(Looper.getMainLooper());
         mUsageStats = new UsageStats(context);
         mLockoutResetDispatcher = lockoutResetDispatcher;
@@ -163,7 +161,8 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
     }
 
     @Nullable
-    private synchronized IFace getHalInstance() {
+    @VisibleForTesting
+    synchronized IFace getHalInstance() {
         if (mTestHalEnabled) {
             return new TestHal();
         }
@@ -214,22 +213,6 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
         mSensors.get(sensorId).getScheduler().scheduleClientMonitor(client, callback);
     }
 
-    private void createNewSessionWithoutHandler(@NonNull IFace daemon, int sensorId,
-            int userId) throws RemoteException {
-        // Note that per IFace createSession contract, this method will block until all
-        // existing operations are canceled/finished. However, also note that this is fine, since
-        // this method "withoutHandler" means it should only ever be invoked from the worker thread,
-        // so callers will never be blocked.
-        mSensors.get(sensorId).createNewSession(daemon, sensorId, userId);
-
-        if (FaceUtils.getInstance(sensorId).isInvalidationInProgress(mContext, userId)) {
-            Slog.w(getTag(), "Scheduling unfinished invalidation request for sensor: " + sensorId
-                    + ", user: " + userId);
-            scheduleInvalidationRequest(sensorId, userId);
-        }
-    }
-
-
     private void scheduleLoadAuthenticatorIds(int sensorId) {
         for (UserInfo user : UserManager.get(mContext).getAliveUsers()) {
             scheduleLoadAuthenticatorIdsForUser(sensorId, user.id);
@@ -238,32 +221,16 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
 
     private void scheduleLoadAuthenticatorIdsForUser(int sensorId, int userId) {
         mHandler.post(() -> {
-            final IFace daemon = getHalInstance();
-            if (daemon == null) {
-                Slog.e(getTag(), "Null daemon during loadAuthenticatorIds, sensorId: " + sensorId);
-                return;
-            }
+            final FaceGetAuthenticatorIdClient client = new FaceGetAuthenticatorIdClient(
+                    mContext, mSensors.get(sensorId).getLazySession(), userId,
+                    mContext.getOpPackageName(), sensorId,
+                    mSensors.get(sensorId).getAuthenticatorIds());
 
-            try {
-                if (!mSensors.get(sensorId).hasSessionForUser(userId)) {
-                    createNewSessionWithoutHandler(daemon, sensorId, userId);
-                }
-
-                final FaceGetAuthenticatorIdClient client = new FaceGetAuthenticatorIdClient(
-                        mContext, mSensors.get(sensorId).getLazySession(), userId,
-                        mContext.getOpPackageName(), sensorId,
-                        mSensors.get(sensorId).getAuthenticatorIds());
-
-                scheduleForSensor(sensorId, client);
-            } catch (RemoteException e) {
-                Slog.e(getTag(), "Remote exception when scheduling loadAuthenticatorId"
-                        + ", sensorId: " + sensorId
-                        + ", userId: " + userId, e);
-            }
+            scheduleForSensor(sensorId, client);
         });
     }
 
-    private void scheduleInvalidationRequest(int sensorId, int userId) {
+    void scheduleInvalidationRequest(int sensorId, int userId) {
         mHandler.post(() -> {
             final InvalidationRequesterClient<Face> client =
                     new InvalidationRequesterClient<>(mContext, userId, sensorId,
@@ -303,25 +270,10 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
     public void scheduleInvalidateAuthenticatorId(int sensorId, int userId,
             @NonNull IInvalidationCallback callback) {
         mHandler.post(() -> {
-            final IFace daemon = getHalInstance();
-            if (daemon == null) {
-                Slog.e(getTag(), "Null daemon during scheduleInvalidateAuthenticatorId: "
-                        + sensorId);
-                return;
-            }
-
-            try {
-                if (!mSensors.get(sensorId).hasSessionForUser(userId)) {
-                    createNewSessionWithoutHandler(daemon, sensorId, userId);
-                }
-
-                final FaceInvalidationClient client = new FaceInvalidationClient(mContext,
-                        mSensors.get(sensorId).getLazySession(), userId, sensorId,
-                        mSensors.get(sensorId).getAuthenticatorIds(), callback);
-                scheduleForSensor(sensorId, client);
-            } catch (RemoteException e) {
-                Slog.e(getTag(), "Remote exception", e);
-            }
+            final FaceInvalidationClient client = new FaceInvalidationClient(mContext,
+                    mSensors.get(sensorId).getLazySession(), userId, sensorId,
+                    mSensors.get(sensorId).getAuthenticatorIds(), callback);
+            scheduleForSensor(sensorId, client);
         });
     }
 
@@ -344,25 +296,10 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
     public void scheduleGenerateChallenge(int sensorId, int userId, @NonNull IBinder token,
             @NonNull IFaceServiceReceiver receiver, String opPackageName) {
         mHandler.post(() -> {
-            final IFace daemon = getHalInstance();
-            if (daemon == null) {
-                Slog.e(getTag(), "Null daemon during generateChallenge, sensorId: " + sensorId);
-                return;
-            }
-
-            try {
-                if (!mSensors.get(sensorId).hasSessionForUser(userId)) {
-                    createNewSessionWithoutHandler(daemon, sensorId, userId);
-                }
-
-                final FaceGenerateChallengeClient client = new FaceGenerateChallengeClient(mContext,
-                        mSensors.get(sensorId).getLazySession(), token,
-                        new ClientMonitorCallbackConverter(receiver), opPackageName, sensorId);
-
-                scheduleForSensor(sensorId, client);
-            } catch (RemoteException e) {
-                Slog.e(getTag(), "Remote exception when scheduling generateChallenge", e);
-            }
+            final FaceGenerateChallengeClient client = new FaceGenerateChallengeClient(mContext,
+                    mSensors.get(sensorId).getLazySession(), token,
+                    new ClientMonitorCallbackConverter(receiver), opPackageName, sensorId);
+            scheduleForSensor(sensorId, client);
         });
     }
 
@@ -370,25 +307,10 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
     public void scheduleRevokeChallenge(int sensorId, int userId, @NonNull IBinder token,
             @NonNull String opPackageName, long challenge) {
         mHandler.post(() -> {
-            final IFace daemon = getHalInstance();
-            if (daemon == null) {
-                Slog.e(getTag(), "Null daemon during revokeChallenge, sensorId: " + sensorId);
-                return;
-            }
-
-            try {
-                if (!mSensors.get(sensorId).hasSessionForUser(userId)) {
-                    createNewSessionWithoutHandler(daemon, sensorId, userId);
-                }
-
-                final FaceRevokeChallengeClient client = new FaceRevokeChallengeClient(mContext,
-                        mSensors.get(sensorId).getLazySession(), token, opPackageName, sensorId,
-                        challenge);
-
-                scheduleForSensor(sensorId, client);
-            } catch (RemoteException e) {
-                Slog.e(getTag(), "Remote exception when scheduling revokeChallenge", e);
-            }
+            final FaceRevokeChallengeClient client = new FaceRevokeChallengeClient(mContext,
+                    mSensors.get(sensorId).getLazySession(), token, opPackageName, sensorId,
+                    challenge);
+            scheduleForSensor(sensorId, client);
         });
     }
 
@@ -398,41 +320,24 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
             @NonNull String opPackageName, @NonNull int[] disabledFeatures,
             @Nullable NativeHandle previewSurface, boolean debugConsent) {
         mHandler.post(() -> {
-            final IFace daemon = getHalInstance();
-            if (daemon == null) {
-                Slog.e(getTag(), "Null daemon during enroll, sensorId: " + sensorId);
-                // If this happens, we need to send HW_UNAVAILABLE after the scheduler gets to
-                // this operation. We should not send the callback yet, since the scheduler may
-                // be processing something else.
-                return;
-            }
-
-            try {
-                if (!mSensors.get(sensorId).hasSessionForUser(userId)) {
-                    createNewSessionWithoutHandler(daemon, sensorId, userId);
-                }
-
-                final int maxTemplatesPerUser = mSensors.get(
-                        sensorId).getSensorProperties().maxEnrollmentsPerUser;
-                final FaceEnrollClient client = new FaceEnrollClient(mContext,
-                        mSensors.get(sensorId).getLazySession(), token,
-                        new ClientMonitorCallbackConverter(receiver), userId, hardwareAuthToken,
-                        opPackageName, FaceUtils.getInstance(sensorId), disabledFeatures,
-                        ENROLL_TIMEOUT_SEC, previewSurface, sensorId, maxTemplatesPerUser,
-                        debugConsent);
-                scheduleForSensor(sensorId, client, new BaseClientMonitor.Callback() {
-                    @Override
-                    public void onClientFinished(@NonNull BaseClientMonitor clientMonitor,
-                            boolean success) {
-                        if (success) {
-                            scheduleLoadAuthenticatorIdsForUser(sensorId, userId);
-                            scheduleInvalidationRequest(sensorId, userId);
-                        }
+            final int maxTemplatesPerUser = mSensors.get(
+                    sensorId).getSensorProperties().maxEnrollmentsPerUser;
+            final FaceEnrollClient client = new FaceEnrollClient(mContext,
+                    mSensors.get(sensorId).getLazySession(), token,
+                    new ClientMonitorCallbackConverter(receiver), userId, hardwareAuthToken,
+                    opPackageName, FaceUtils.getInstance(sensorId), disabledFeatures,
+                    ENROLL_TIMEOUT_SEC, previewSurface, sensorId, maxTemplatesPerUser,
+                    debugConsent);
+            scheduleForSensor(sensorId, client, new BaseClientMonitor.Callback() {
+                @Override
+                public void onClientFinished(@NonNull BaseClientMonitor clientMonitor,
+                        boolean success) {
+                    if (success) {
+                        scheduleLoadAuthenticatorIdsForUser(sensorId, userId);
+                        scheduleInvalidationRequest(sensorId, userId);
                     }
-                });
-            } catch (RemoteException e) {
-                Slog.e(getTag(), "Remote exception when scheduling enroll", e);
-            }
+                }
+            });
         });
     }
 
@@ -447,31 +352,14 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
             @NonNull String opPackageName, boolean restricted, int statsClient,
             boolean allowBackgroundAuthentication) {
         mHandler.post(() -> {
-            final IFace daemon = getHalInstance();
-            if (daemon == null) {
-                Slog.e(getTag(), "Null daemon during authenticate, sensorId: " + sensorId);
-                // If this happens, we need to send HW_UNAVAILABLE after the scheduler gets to
-                // this operation. We should not send the callback yet, since the scheduler may
-                // be processing something else.
-                return;
-            }
-
-            try {
-                if (!mSensors.get(sensorId).hasSessionForUser(userId)) {
-                    createNewSessionWithoutHandler(daemon, sensorId, userId);
-                }
-
-                final boolean isStrongBiometric = Utils.isStrongBiometric(sensorId);
-                final FaceAuthenticationClient client = new FaceAuthenticationClient(
-                        mContext, mSensors.get(sensorId).getLazySession(), token, callback, userId,
-                        operationId, restricted, opPackageName, cookie,
-                        false /* requireConfirmation */, sensorId, isStrongBiometric, statsClient,
-                        mUsageStats, mSensors.get(sensorId).getLockoutCache(),
-                        allowBackgroundAuthentication);
-                scheduleForSensor(sensorId, client);
-            } catch (RemoteException e) {
-                Slog.e(getTag(), "Remote exception when scheduling authenticate", e);
-            }
+            final boolean isStrongBiometric = Utils.isStrongBiometric(sensorId);
+            final FaceAuthenticationClient client = new FaceAuthenticationClient(
+                    mContext, mSensors.get(sensorId).getLazySession(), token, callback, userId,
+                    operationId, restricted, opPackageName, cookie,
+                    false /* requireConfirmation */, sensorId, isStrongBiometric, statsClient,
+                    mUsageStats, mSensors.get(sensorId).getLockoutCache(),
+                    allowBackgroundAuthentication);
+            scheduleForSensor(sensorId, client);
         });
     }
 
@@ -503,56 +391,24 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
     private void scheduleRemoveSpecifiedIds(int sensorId, @NonNull IBinder token, int[] faceIds,
             int userId, @NonNull IFaceServiceReceiver receiver, @NonNull String opPackageName) {
         mHandler.post(() -> {
-            final IFace daemon = getHalInstance();
-            if (daemon == null) {
-                Slog.e(getTag(), "Null daemon during remove, sensorId: " + sensorId);
-                // If this happens, we need to send HW_UNAVAILABLE after the scheduler gets to
-                // this operation. We should not send the callback yet, since the scheduler may
-                // be processing something else.
-                return;
-            }
-
-            try {
-                if (!mSensors.get(sensorId).hasSessionForUser(userId)) {
-                    createNewSessionWithoutHandler(daemon, sensorId, userId);
-                }
-
-                final FaceRemovalClient client = new FaceRemovalClient(mContext,
-                        mSensors.get(sensorId).getLazySession(), token,
-                        new ClientMonitorCallbackConverter(receiver), faceIds, userId,
-                        opPackageName, FaceUtils.getInstance(sensorId), sensorId,
-                        mSensors.get(sensorId).getAuthenticatorIds());
-
-                scheduleForSensor(sensorId, client);
-            } catch (RemoteException e) {
-                Slog.e(getTag(), "Remote exception when scheduling remove", e);
-            }
+            final FaceRemovalClient client = new FaceRemovalClient(mContext,
+                    mSensors.get(sensorId).getLazySession(), token,
+                    new ClientMonitorCallbackConverter(receiver), faceIds, userId,
+                    opPackageName, FaceUtils.getInstance(sensorId), sensorId,
+                    mSensors.get(sensorId).getAuthenticatorIds());
+            scheduleForSensor(sensorId, client);
         });
     }
 
     @Override
     public void scheduleResetLockout(int sensorId, int userId, @NonNull byte[] hardwareAuthToken) {
         mHandler.post(() -> {
-            final IFace daemon = getHalInstance();
-            if (daemon == null) {
-                Slog.e(getTag(), "Null daemon during resetLockout, sensorId: " + sensorId);
-                return;
-            }
+            final FaceResetLockoutClient client = new FaceResetLockoutClient(
+                    mContext, mSensors.get(sensorId).getLazySession(), userId,
+                    mContext.getOpPackageName(), sensorId, hardwareAuthToken,
+                    mSensors.get(sensorId).getLockoutCache(), mLockoutResetDispatcher);
 
-            try {
-                if (!mSensors.get(sensorId).hasSessionForUser(userId)) {
-                    createNewSessionWithoutHandler(daemon, sensorId, userId);
-                }
-
-                final FaceResetLockoutClient client = new FaceResetLockoutClient(
-                        mContext, mSensors.get(sensorId).getLazySession(), userId,
-                        mContext.getOpPackageName(), sensorId, hardwareAuthToken,
-                        mSensors.get(sensorId).getLockoutCache(), mLockoutResetDispatcher);
-
-                scheduleForSensor(sensorId, client);
-            } catch (RemoteException e) {
-                Slog.e(getTag(), "Remote exception when scheduling resetLockout", e);
-            }
+            scheduleForSensor(sensorId, client);
         });
     }
 
@@ -580,29 +436,14 @@ public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
     public void scheduleInternalCleanup(int sensorId, int userId,
             @Nullable BaseClientMonitor.Callback callback) {
         mHandler.post(() -> {
-            final IFace daemon = getHalInstance();
-            if (daemon == null) {
-                Slog.e(getTag(), "Null daemon during internal cleanup, sensorId: " + sensorId);
-                return;
-            }
-
-            try {
-                if (!mSensors.get(sensorId).hasSessionForUser(userId)) {
-                    createNewSessionWithoutHandler(daemon, sensorId, userId);
-                }
-
-                final List<Face> enrolledList = getEnrolledFaces(sensorId, userId);
-                final FaceInternalCleanupClient client =
-                        new FaceInternalCleanupClient(mContext,
-                                mSensors.get(sensorId).getLazySession(), userId,
-                                mContext.getOpPackageName(), sensorId, enrolledList,
-                                FaceUtils.getInstance(sensorId),
-                                mSensors.get(sensorId).getAuthenticatorIds());
-
-                scheduleForSensor(sensorId, client);
-            } catch (RemoteException e) {
-                Slog.e(getTag(), "Remote exception when scheduling internal cleanup", e);
-            }
+            final List<Face> enrolledList = getEnrolledFaces(sensorId, userId);
+            final FaceInternalCleanupClient client =
+                    new FaceInternalCleanupClient(mContext,
+                            mSensors.get(sensorId).getLazySession(), userId,
+                            mContext.getOpPackageName(), sensorId, enrolledList,
+                            FaceUtils.getInstance(sensorId),
+                            mSensors.get(sensorId).getAuthenticatorIds());
+            scheduleForSensor(sensorId, client);
         });
     }
 

services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceStartUserClient.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.biometrics.sensors.face.aidl;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.content.Context;
+import android.hardware.biometrics.face.IFace;
+import android.hardware.biometrics.face.ISession;
+import android.hardware.biometrics.face.ISessionCallback;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.util.Slog;
+
+import com.android.server.biometrics.sensors.StartUserClient;
+
+public class FaceStartUserClient extends StartUserClient<IFace, ISession> {
+    private static final String TAG = "FaceStartUserClient";
+
+    @NonNull private final ISessionCallback mSessionCallback;
+
+    public FaceStartUserClient(@NonNull Context context, @NonNull LazyDaemon<IFace> lazyDaemon,
+            @Nullable IBinder token, int userId, int sensorId,
+            @NonNull ISessionCallback sessionCallback,
+            @NonNull UserStartedCallback<ISession> callback) {
+        super(context, lazyDaemon, token, userId, sensorId, callback);
+        mSessionCallback = sessionCallback;
+    }
+
+    @Override
+    public void start(@NonNull Callback callback) {
+        super.start(callback);
+        startHalOperation();
+    }
+
+    @Override
+    protected void startHalOperation() {
+        try {
+            final ISession newSession = getFreshDaemon().createSession(getSensorId(),
+                    getTargetUserId(), mSessionCallback);
+            mUserStartedCallback.onUserStarted(getTargetUserId(), newSession);
+            getCallback().onClientFinished(this, true /* success */);
+        } catch (RemoteException e) {
+            Slog.e(TAG, "Remote exception", e);
+            getCallback().onClientFinished(this, false /* success */);
+        }
+    }
+
+    @Override
+    public void unableToStart() {
+
+    }
+}

services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceStopUserClient.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.biometrics.sensors.face.aidl;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.content.Context;
+import android.hardware.biometrics.face.ISession;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.util.Slog;
+
+import com.android.server.biometrics.sensors.StopUserClient;
+
+public class FaceStopUserClient extends StopUserClient<ISession> {
+    private static final String TAG = "FaceStopUserClient";
+
+    public FaceStopUserClient(@NonNull Context context, @NonNull LazyDaemon<ISession> lazyDaemon,
+            @Nullable IBinder token, int userId, int sensorId,
+            @NonNull UserStoppedCallback callback) {
+        super(context, lazyDaemon, token, userId, sensorId, callback);
+    }
+
+    @Override
+    public void start(@NonNull Callback callback) {
+        super.start(callback);
+        startHalOperation();
+    }
+
+    @Override
+    protected void startHalOperation() {
+        try {
+            getFreshDaemon().close(mSequentialId);
+        } catch (RemoteException e) {
+            Slog.e(TAG, "Remote exception", e);
+            getCallback().onClientFinished(this, false /* success */);
+        }
+    }
+
+    @Override
+    public void unableToStart() {
+
+    }
+}

services/core/java/com/android/server/biometrics/sensors/face/aidl/Sensor.java

@@ -33,8 +33,11 @@ import android.hardware.face.Face;
 import android.hardware.face.FaceManager;
 import android.hardware.face.FaceSensorPropertiesInternal;
 import android.hardware.keymaster.HardwareAuthToken;
+import android.os.Binder;
 import android.os.Handler;
+import android.os.IBinder;
 import android.os.RemoteException;
+import android.os.UserHandle;
 import android.os.UserManager;
 import android.util.Slog;
 import android.util.proto.ProtoOutputStream;
@@ -54,6 +57,9 @@ import com.android.server.biometrics.sensors.Interruptable;
 import com.android.server.biometrics.sensors.LockoutCache;
 import com.android.server.biometrics.sensors.LockoutConsumer;
 import com.android.server.biometrics.sensors.RemovalConsumer;
+import com.android.server.biometrics.sensors.StartUserClient;
+import com.android.server.biometrics.sensors.StopUserClient;
+import com.android.server.biometrics.sensors.UserAwareBiometricScheduler;
 import com.android.server.biometrics.sensors.face.FaceUtils;
 
 import java.util.ArrayList;
@@ -70,9 +76,10 @@ public class Sensor {
     @NonNull private final String mTag;
     @NonNull private final FaceProvider mProvider;
     @NonNull private final Context mContext;
+    @NonNull private final IBinder mToken;
     @NonNull private final Handler mHandler;
     @NonNull private final FaceSensorPropertiesInternal mSensorProperties;
-    @NonNull private final BiometricScheduler mScheduler;
+    @NonNull private final UserAwareBiometricScheduler mScheduler;
     @NonNull private final LockoutCache mLockoutCache;
     @NonNull private final Map<Integer, Long> mAuthenticatorIds;
     @NonNull private final HalClientMonitor.LazyDaemon<ISession> mLazySession;
@@ -427,7 +434,15 @@ public class Sensor {
         @Override
         public void onSessionClosed() {
             mHandler.post(() -> {
-              // TODO: implement this.
+                final BaseClientMonitor client = mScheduler.getCurrentClient();
+                if (!(client instanceof FaceStopUserClient)) {
+                    Slog.e(mTag, "onSessionClosed for wrong consumer: "
+                            + Utils.getClientName(client));
+                    return;
+                }
+
+                final FaceStopUserClient stopUserClient = (FaceStopUserClient) client;
+                stopUserClient.onUserStopped();
             });
         }
     }
@@ -437,9 +452,53 @@ public class Sensor {
         mTag = tag;
         mProvider = provider;
         mContext = context;
+        mToken = new Binder();
         mHandler = handler;
         mSensorProperties = sensorProperties;
-        mScheduler = new BiometricScheduler(tag, null /* gestureAvailabilityDispatcher */);
+        mScheduler = new UserAwareBiometricScheduler(tag, null /* gestureAvailabilityDispatcher */,
+                () -> mCurrentSession != null ? mCurrentSession.mUserId : UserHandle.USER_NULL,
+                new UserAwareBiometricScheduler.UserSwitchCallback() {
+                    @NonNull
+                    @Override
+                    public StopUserClient<?> getStopUserClient(int userId) {
+                        return new FaceStopUserClient(mContext, mLazySession, mToken, userId,
+                                mSensorProperties.sensorId, () -> mCurrentSession = null);
+                    }
+
+                    @NonNull
+                    @Override
+                    public StartUserClient<?, ?> getStartUserClient(int newUserId) {
+                        final HalSessionCallback.Callback callback = () -> {
+                            Slog.e(mTag, "Got ERROR_HW_UNAVAILABLE");
+                            mCurrentSession = null;
+                        };
+
+                        final int sensorId = mSensorProperties.sensorId;
+
+                        final HalSessionCallback resultController = new HalSessionCallback(mContext,
+                                mHandler, mTag, mScheduler, sensorId, newUserId, callback);
+
+                        final StartUserClient.UserStartedCallback<ISession> userStartedCallback =
+                                (userIdStarted, newSession) -> {
+                                    mCurrentSession = new Session(mTag, newSession, userIdStarted,
+                                            resultController);
+                                    if (FaceUtils.getLegacyInstance(sensorId)
+                                            .isInvalidationInProgress(mContext, userIdStarted)) {
+                                        Slog.w(mTag,
+                                                "Scheduling unfinished invalidation request for "
+                                                        + "sensor: "
+                                                        + sensorId
+                                                        + ", user: " + userIdStarted);
+                                        provider.scheduleInvalidationRequest(sensorId,
+                                                userIdStarted);
+                                    }
+                                };
+
+                        return new FaceStartUserClient(mContext, provider::getHalInstance,
+                                mToken, newUserId, mSensorProperties.sensorId,
+                                resultController, userStartedCallback);
+                    }
+                });
         mLockoutCache = new LockoutCache();
         mAuthenticatorIds = new HashMap<>();
         mLazySession = () -> mCurrentSession != null ? mCurrentSession.mSession : null;
@@ -453,11 +512,6 @@ public class Sensor {
         return mSensorProperties;
     }
 
-    @SuppressWarnings("BooleanMethodIsAlwaysInverted")
-    boolean hasSessionForUser(int userId) {
-        return mCurrentSession != null && mCurrentSession.mUserId == userId;
-    }
-
     @Nullable Session getSessionForUser(int userId) {
         if (mCurrentSession != null && mCurrentSession.mUserId == userId) {
             return mCurrentSession;
@@ -471,20 +525,6 @@ public class Sensor {
                 mProvider, this);
     }
 
-    void createNewSession(@NonNull IFace daemon, int sensorId, int userId)
-            throws RemoteException {
-
-        final HalSessionCallback.Callback callback = () -> {
-            Slog.e(mTag, "Got ERROR_HW_UNAVAILABLE");
-            mCurrentSession = null;
-        };
-        final HalSessionCallback resultController = new HalSessionCallback(mContext, mHandler,
-                mTag, mScheduler, sensorId, userId, callback);
-
-        final ISession newSession = daemon.createSession(sensorId, userId, resultController);
-        mCurrentSession = new Session(mTag, newSession, userId, resultController);
-    }
-
     @NonNull BiometricScheduler getScheduler() {
         return mScheduler;
     }

services/tests/servicestests/src/com/android/server/biometrics/sensors/face/aidl/FaceProviderTest.java

@@ -24,10 +24,12 @@ import static org.mockito.Mockito.when;
 
 import android.content.Context;
 import android.hardware.biometrics.common.CommonProps;
+import android.hardware.biometrics.face.IFace;
 import android.hardware.biometrics.face.SensorProps;
 import android.os.UserManager;
 import android.platform.test.annotations.Presubmit;
 
+import androidx.annotation.NonNull;
 import androidx.test.InstrumentationRegistry;
 import androidx.test.filters.SmallTest;
 
@@ -56,7 +58,7 @@ public class FaceProviderTest {
 
     private SensorProps[] mSensorProps;
     private LockoutResetDispatcher mLockoutResetDispatcher;
-    private FaceProvider mFaceProvider;
+    private TestableFaceProvider mFaceProvider;
 
     private static void waitForIdle() {
         InstrumentationRegistry.getInstrumentation().waitForIdleSync();
@@ -80,7 +82,7 @@ public class FaceProviderTest {
 
         mLockoutResetDispatcher = new LockoutResetDispatcher(mContext);
 
-        mFaceProvider = new FaceProvider(mContext, mSensorProps, TAG,
+        mFaceProvider = new TestableFaceProvider(mContext, mSensorProps, TAG,
                 mLockoutResetDispatcher);
     }
 
@@ -123,4 +125,19 @@ public class FaceProviderTest {
             assertEquals(0, scheduler.getCurrentPendingCount());
         }
     }
+
+    private static class TestableFaceProvider extends FaceProvider {
+        public TestableFaceProvider(@NonNull Context context,
+                @NonNull SensorProps[] props,
+                @NonNull String halInstanceName,
+                @NonNull LockoutResetDispatcher lockoutResetDispatcher) {
+            super(context, props, halInstanceName, lockoutResetDispatcher);
+        }
+
+        @Override
+        synchronized IFace getHalInstance() {
+            return mock(IFace.class);
+        }
+    }
+
 }