services/core/java/com/android/server/biometrics/sensors/BaseClientMonitor.java - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2020 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;

 import static com.android.internal.annotations.VisibleForTesting.Visibility;

 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.content.Context;
 import android.hardware.biometrics.BiometricsProtoEnums;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Slog;

 import com.android.internal.annotations.VisibleForTesting;

 import java.util.ArrayList;
 import java.util.List;
 import java.util.NoSuchElementException;

 /**
  * Abstract base class for keeping track and dispatching events from the biometric's HAL to the
  * the current client.  Subclasses are responsible for coordinating the interaction with
  * the biometric's HAL for the specific action (e.g. authenticate, enroll, enumerate, etc.).
  */
 public abstract class BaseClientMonitor extends LoggableMonitor
         implements IBinder.DeathRecipient {

     private static final String TAG = "Biometrics/ClientMonitor";
     protected static final boolean DEBUG = true;

     // Counter used to distinguish between ClientMonitor instances to help debugging.
     private static int sCount = 0;

     /**
      * Interface that ClientMonitor holders should use to receive callbacks.
      */
     public interface Callback {
         /**
          * Invoked when the ClientMonitor operation has been started (e.g. reached the head of
          * the queue and becomes the current operation).
          *
          * @param clientMonitor Reference of the ClientMonitor that is starting.
          */
         default void onClientStarted(@NonNull BaseClientMonitor clientMonitor) {
         }

         /**
          * Invoked when the ClientMonitor operation is complete. This abstracts away asynchronous
          * (i.e. Authenticate, Enroll, Enumerate, Remove) and synchronous (i.e. generateChallenge,
          * revokeChallenge) so that a scheduler can process ClientMonitors regardless of their
          * implementation.
          *
          * @param clientMonitor Reference of the ClientMonitor that finished.
          * @param success True if the operation completed successfully.
          */
         default void onClientFinished(@NonNull BaseClientMonitor clientMonitor, boolean success) {
         }
     }

     /** Holder for wrapping multiple handlers into a single Callback. */
     public static class CompositeCallback implements Callback {
         @NonNull
         private final List<Callback> mCallbacks;

         public CompositeCallback(@NonNull Callback... callbacks) {
             mCallbacks = new ArrayList<>();

             for (Callback callback : callbacks) {
                 if (callback != null) {
                     mCallbacks.add(callback);
                 }
             }
         }

         @Override
         public final void onClientStarted(@NonNull BaseClientMonitor clientMonitor) {
             for (int i = 0; i < mCallbacks.size(); i++) {
                 mCallbacks.get(i).onClientStarted(clientMonitor);
             }
         }

         @Override
         public final void onClientFinished(@NonNull BaseClientMonitor clientMonitor,
                 boolean success) {
             for (int i = mCallbacks.size() - 1; i >= 0; i--) {
                 mCallbacks.get(i).onClientFinished(clientMonitor, success);
             }
         }
     }

     private final int mSequentialId;
     @NonNull private final Context mContext;
     private final int mTargetUserId;
     @NonNull private final String mOwner;
     private final int mSensorId; // sensorId as configured by the framework

     @Nullable private IBinder mToken;
     private long mRequestId;
     @Nullable private ClientMonitorCallbackConverter mListener;
     // Currently only used for authentication client. The cookie generated by BiometricService
     // is never 0.
     private final int mCookie;
     private boolean mAlreadyDone = false;

     // Use an empty callback by default since delayed operations can receive events
     // before they are started and cause NPE in subclasses that access this field directly.
     @NonNull protected Callback mCallback = new Callback() {
         @Override
         public void onClientStarted(@NonNull BaseClientMonitor clientMonitor) {
             Slog.e(TAG, "mCallback onClientStarted: called before set (should not happen)");
         }

         @Override
         public void onClientFinished(@NonNull BaseClientMonitor clientMonitor,
                 boolean success) {
             Slog.e(TAG, "mCallback onClientFinished: called before set (should not happen)");
         }
     };

     /**
      * @return A ClientMonitorEnum constant defined in biometrics.proto
      */
     public abstract int getProtoEnum();

     /**
      * @return True if the ClientMonitor should cancel any current and pending interruptable clients
      */
     public boolean interruptsPrecedingClients() {
         return false;
     }

     /**
      * @param context    system_server context
      * @param token      a unique token for the client
      * @param listener   recipient of related events (e.g. authentication)
      * @param userId     target user id for operation
      * @param owner      name of the client that owns this
      * @param cookie     BiometricPrompt authentication cookie (to be moved into a subclass soon)
      * @param sensorId   ID of the sensor that the operation should be requested of
      * @param statsModality One of {@link BiometricsProtoEnums} MODALITY_* constants
      * @param statsAction   One of {@link BiometricsProtoEnums} ACTION_* constants
      * @param statsClient   One of {@link BiometricsProtoEnums} CLIENT_* constants
      */
     public BaseClientMonitor(@NonNull Context context,
             @Nullable IBinder token, @Nullable ClientMonitorCallbackConverter listener, int userId,
             @NonNull String owner, int cookie, int sensorId, int statsModality, int statsAction,
             int statsClient) {
         super(context, statsModality, statsAction, statsClient);
         mSequentialId = sCount++;
         mContext = context;
         mToken = token;
         mRequestId = -1;
         mListener = listener;
         mTargetUserId = userId;
         mOwner = owner;
         mCookie = cookie;
         mSensorId = sensorId;

         try {
             if (token != null) {
                 token.linkToDeath(this, 0);
             }
         } catch (RemoteException e) {
             Slog.w(TAG, "caught remote exception in linkToDeath: ", e);
         }
     }

     public int getCookie() {
         return mCookie;
     }

     /**
      * Starts the ClientMonitor's lifecycle.
      * @param callback invoked when the operation is complete (succeeds, fails, etc)
      */
     public void start(@NonNull Callback callback) {
         mCallback = wrapCallbackForStart(callback);
         mCallback.onClientStarted(this);
     }

     /**
      * Called during start to provide subclasses a hook for decorating the callback.
      *
      * Returns the original callback unless overridden.
      */
     @NonNull
     protected Callback wrapCallbackForStart(@NonNull Callback callback) {
         return callback;
     }

     /** Signals this operation has completed its lifecycle and should no longer be used. */
     @VisibleForTesting(visibility = Visibility.PACKAGE)
     public void destroy() {
         mAlreadyDone = true;
         if (mToken != null) {
             try {
                 mToken.unlinkToDeath(this, 0);
             } catch (NoSuchElementException e) {
                 // TODO: remove when duplicate call bug is found
                 Slog.e(TAG, "destroy(): " + this + ":", new Exception("here"));
             }
             mToken = null;
         }
     }

     /**
      * Call while the operation is still active, but nearly done, to prevent any action
      * upon client death (only needed for authentication clients).
      */
     void markAlreadyDone() {
         Slog.d(TAG, "marking operation as done: " + this);
         mAlreadyDone = true;
     }

     /** If this operation has been marked as completely done (or cancelled). */
     public boolean isAlreadyDone() {
         return mAlreadyDone;
     }

     @Override
     public void binderDied() {
         binderDiedInternal(true /* clearListener */);
     }

     // TODO(b/157790417): Move this to the scheduler
     void binderDiedInternal(boolean clearListener) {
         Slog.e(TAG, "Binder died, operation: " + this);

         if (mAlreadyDone) {
             Slog.w(TAG, "Binder died but client is finished, ignoring");
             return;
         }

         // If the current client dies we should cancel the current operation.
         if (this instanceof Interruptable) {
             Slog.e(TAG, "Binder died, cancelling client");
             ((Interruptable) this).cancel();
         }
         mToken = null;
         if (clearListener) {
             mListener = null;
         }
     }

     public final Context getContext() {
         return mContext;
     }

     public final String getOwnerString() {
         return mOwner;
     }

     public final ClientMonitorCallbackConverter getListener() {
         return mListener;
     }

     public int getTargetUserId() {
         return mTargetUserId;
     }

     public final IBinder getToken() {
         return mToken;
     }

     public int getSensorId() {
         return mSensorId;
     }

     /** Unique request id. */
     public final long getRequestId() {
         return mRequestId;
     }

     /** If a unique id has been set via {@link #setRequestId(long)} */
     public final boolean hasRequestId() {
         return mRequestId > 0;
     }

     /**
      * A unique identifier used to tie this operation to a request (i.e an API invocation).
      *
      * Subclasses should not call this method if this operation does not have a direct
      * correspondence to a request and {@link #hasRequestId()} will return false.
      */
     protected final void setRequestId(long id) {
         if (id <= 0) {
             throw new IllegalArgumentException("request id must be positive");
         }
         mRequestId = id;
     }

     @VisibleForTesting
     public Callback getCallback() {
         return mCallback;
     }

     @Override
     public String toString() {
         return "{[" + mSequentialId + "] "
                 + this.getClass().getName()
                 + ", proto=" + getProtoEnum()
                 + ", owner=" + getOwnerString()
                 + ", cookie=" + getCookie()
                 + ", requestId=" + getRequestId()
                 + ", userId=" + getTargetUserId() + "}";
     }
 }
	/*
	* Copyright (C) 2020 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;

	import static com.android.internal.annotations.VisibleForTesting.Visibility;

	import android.annotation.NonNull;
	import android.annotation.Nullable;
	import android.content.Context;
	import android.hardware.biometrics.BiometricsProtoEnums;
	import android.os.IBinder;
	import android.os.RemoteException;
	import android.util.Slog;

	import com.android.internal.annotations.VisibleForTesting;

	import java.util.ArrayList;
	import java.util.List;
	import java.util.NoSuchElementException;

	/**
	* Abstract base class for keeping track and dispatching events from the biometric's HAL to the
	* the current client. Subclasses are responsible for coordinating the interaction with
	* the biometric's HAL for the specific action (e.g. authenticate, enroll, enumerate, etc.).
	*/
	public abstract class BaseClientMonitor extends LoggableMonitor
	implements IBinder.DeathRecipient {

	private static final String TAG = "Biometrics/ClientMonitor";
	protected static final boolean DEBUG = true;

	// Counter used to distinguish between ClientMonitor instances to help debugging.
	private static int sCount = 0;

	/**
	* Interface that ClientMonitor holders should use to receive callbacks.
	*/
	public interface Callback {
	/**
	* Invoked when the ClientMonitor operation has been started (e.g. reached the head of
	* the queue and becomes the current operation).
	*
	* @param clientMonitor Reference of the ClientMonitor that is starting.
	*/
	default void onClientStarted(@NonNull BaseClientMonitor clientMonitor) {
	}

	/**
	* Invoked when the ClientMonitor operation is complete. This abstracts away asynchronous
	* (i.e. Authenticate, Enroll, Enumerate, Remove) and synchronous (i.e. generateChallenge,
	* revokeChallenge) so that a scheduler can process ClientMonitors regardless of their
	* implementation.
	*
	* @param clientMonitor Reference of the ClientMonitor that finished.
	* @param success True if the operation completed successfully.
	*/
	default void onClientFinished(@NonNull BaseClientMonitor clientMonitor, boolean success) {
	}
	}

	/** Holder for wrapping multiple handlers into a single Callback. */
	public static class CompositeCallback implements Callback {
	@NonNull
	private final List<Callback> mCallbacks;

	public CompositeCallback(@NonNull Callback... callbacks) {
	mCallbacks = new ArrayList<>();

	for (Callback callback : callbacks) {
	if (callback != null) {
	mCallbacks.add(callback);
	}
	}
	}

	@Override
	public final void onClientStarted(@NonNull BaseClientMonitor clientMonitor) {
	for (int i = 0; i < mCallbacks.size(); i++) {
	mCallbacks.get(i).onClientStarted(clientMonitor);
	}
	}

	@Override
	public final void onClientFinished(@NonNull BaseClientMonitor clientMonitor,
	boolean success) {
	for (int i = mCallbacks.size() - 1; i >= 0; i--) {
	mCallbacks.get(i).onClientFinished(clientMonitor, success);
	}
	}
	}

	private final int mSequentialId;
	@NonNull private final Context mContext;
	private final int mTargetUserId;
	@NonNull private final String mOwner;
	private final int mSensorId; // sensorId as configured by the framework

	@Nullable private IBinder mToken;
	private long mRequestId;
	@Nullable private ClientMonitorCallbackConverter mListener;
	// Currently only used for authentication client. The cookie generated by BiometricService
	// is never 0.
	private final int mCookie;
	private boolean mAlreadyDone = false;

	// Use an empty callback by default since delayed operations can receive events
	// before they are started and cause NPE in subclasses that access this field directly.
	@NonNull protected Callback mCallback = new Callback() {
	@Override
	public void onClientStarted(@NonNull BaseClientMonitor clientMonitor) {
	Slog.e(TAG, "mCallback onClientStarted: called before set (should not happen)");
	}

	@Override
	public void onClientFinished(@NonNull BaseClientMonitor clientMonitor,
	boolean success) {
	Slog.e(TAG, "mCallback onClientFinished: called before set (should not happen)");
	}
	};

	/**
	* @return A ClientMonitorEnum constant defined in biometrics.proto
	*/
	public abstract int getProtoEnum();

	/**
	* @return True if the ClientMonitor should cancel any current and pending interruptable clients
	*/
	public boolean interruptsPrecedingClients() {
	return false;
	}

	/**
	* @param context system_server context
	* @param token a unique token for the client
	* @param listener recipient of related events (e.g. authentication)
	* @param userId target user id for operation
	* @param owner name of the client that owns this
	* @param cookie BiometricPrompt authentication cookie (to be moved into a subclass soon)
	* @param sensorId ID of the sensor that the operation should be requested of
	* @param statsModality One of {@link BiometricsProtoEnums} MODALITY_* constants
	* @param statsAction One of {@link BiometricsProtoEnums} ACTION_* constants
	* @param statsClient One of {@link BiometricsProtoEnums} CLIENT_* constants
	*/
	public BaseClientMonitor(@NonNull Context context,
	@Nullable IBinder token, @Nullable ClientMonitorCallbackConverter listener, int userId,
	@NonNull String owner, int cookie, int sensorId, int statsModality, int statsAction,
	int statsClient) {
	super(context, statsModality, statsAction, statsClient);
	mSequentialId = sCount++;
	mContext = context;
	mToken = token;
	mRequestId = -1;
	mListener = listener;
	mTargetUserId = userId;
	mOwner = owner;
	mCookie = cookie;
	mSensorId = sensorId;

	try {
	if (token != null) {
	token.linkToDeath(this, 0);
	}
	} catch (RemoteException e) {
	Slog.w(TAG, "caught remote exception in linkToDeath: ", e);
	}
	}

	public int getCookie() {
	return mCookie;
	}

	/**
	* Starts the ClientMonitor's lifecycle.
	* @param callback invoked when the operation is complete (succeeds, fails, etc)
	*/
	public void start(@NonNull Callback callback) {
	mCallback = wrapCallbackForStart(callback);
	mCallback.onClientStarted(this);
	}

	/**
	* Called during start to provide subclasses a hook for decorating the callback.
	*
	* Returns the original callback unless overridden.
	*/
	@NonNull
	protected Callback wrapCallbackForStart(@NonNull Callback callback) {
	return callback;
	}

	/** Signals this operation has completed its lifecycle and should no longer be used. */
	@VisibleForTesting(visibility = Visibility.PACKAGE)
	public void destroy() {
	mAlreadyDone = true;
	if (mToken != null) {
	try {
	mToken.unlinkToDeath(this, 0);
	} catch (NoSuchElementException e) {
	// TODO: remove when duplicate call bug is found
	Slog.e(TAG, "destroy(): " + this + ":", new Exception("here"));
	}
	mToken = null;
	}
	}

	/**
	* Call while the operation is still active, but nearly done, to prevent any action
	* upon client death (only needed for authentication clients).
	*/
	void markAlreadyDone() {
	Slog.d(TAG, "marking operation as done: " + this);
	mAlreadyDone = true;
	}

	/** If this operation has been marked as completely done (or cancelled). */
	public boolean isAlreadyDone() {
	return mAlreadyDone;
	}

	@Override
	public void binderDied() {
	binderDiedInternal(true /* clearListener */);
	}

	// TODO(b/157790417): Move this to the scheduler
	void binderDiedInternal(boolean clearListener) {
	Slog.e(TAG, "Binder died, operation: " + this);

	if (mAlreadyDone) {
	Slog.w(TAG, "Binder died but client is finished, ignoring");
	return;
	}

	// If the current client dies we should cancel the current operation.
	if (this instanceof Interruptable) {
	Slog.e(TAG, "Binder died, cancelling client");
	((Interruptable) this).cancel();
	}
	mToken = null;
	if (clearListener) {
	mListener = null;
	}
	}

	public final Context getContext() {
	return mContext;
	}

	public final String getOwnerString() {
	return mOwner;
	}

	public final ClientMonitorCallbackConverter getListener() {
	return mListener;
	}

	public int getTargetUserId() {
	return mTargetUserId;
	}

	public final IBinder getToken() {
	return mToken;
	}

	public int getSensorId() {
	return mSensorId;
	}

	/** Unique request id. */
	public final long getRequestId() {
	return mRequestId;
	}

	/** If a unique id has been set via {@link #setRequestId(long)} */
	public final boolean hasRequestId() {
	return mRequestId > 0;
	}

	/**
	* A unique identifier used to tie this operation to a request (i.e an API invocation).
	*
	* Subclasses should not call this method if this operation does not have a direct
	* correspondence to a request and {@link #hasRequestId()} will return false.
	*/
	protected final void setRequestId(long id) {
	if (id <= 0) {
	throw new IllegalArgumentException("request id must be positive");
	}
	mRequestId = id;
	}

	@VisibleForTesting
	public Callback getCallback() {
	return mCallback;
	}

	@Override
	public String toString() {
	return "{[" + mSequentialId + "] "
	+ this.getClass().getName()
	+ ", proto=" + getProtoEnum()
	+ ", owner=" + getOwnerString()
	+ ", cookie=" + getCookie()
	+ ", requestId=" + getRequestId()
	+ ", userId=" + getTargetUserId() + "}";
	}
	}