services/companion/java/com/android/server/companion/virtual/InputController.java

/*
 * 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.companion.virtual;

import android.annotation.IntDef;
import android.annotation.NonNull;
import android.annotation.StringDef;
import android.graphics.Point;
import android.graphics.PointF;
import android.hardware.display.DisplayManagerInternal;
import android.hardware.input.InputDeviceIdentifier;
import android.hardware.input.InputManager;
import android.hardware.input.InputManagerInternal;
import android.hardware.input.VirtualKeyEvent;
import android.hardware.input.VirtualMouseButtonEvent;
import android.hardware.input.VirtualMouseRelativeEvent;
import android.hardware.input.VirtualMouseScrollEvent;
import android.hardware.input.VirtualTouchEvent;
import android.os.Handler;
import android.os.IBinder;
import android.os.RemoteException;
import android.util.ArrayMap;
import android.util.Slog;
import android.view.Display;
import android.view.InputDevice;
import android.view.WindowManager;

import com.android.internal.annotations.GuardedBy;
import com.android.internal.annotations.VisibleForTesting;
import com.android.server.LocalServices;

import java.io.PrintWriter;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.Iterator;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Supplier;

/** Controls virtual input devices, including device lifecycle and event dispatch. */
class InputController {

    private static final String TAG = "VirtualInputController";

    private static final AtomicLong sNextPhysId = new AtomicLong(1);

    static final String PHYS_TYPE_KEYBOARD = "Keyboard";
    static final String PHYS_TYPE_MOUSE = "Mouse";
    static final String PHYS_TYPE_TOUCHSCREEN = "Touchscreen";
    @StringDef(prefix = { "PHYS_TYPE_" }, value = {
            PHYS_TYPE_KEYBOARD,
            PHYS_TYPE_MOUSE,
            PHYS_TYPE_TOUCHSCREEN,
    })
    @Retention(RetentionPolicy.SOURCE)
    @interface PhysType {
    }

    private final Object mLock;

    /* Token -> file descriptor associations. */
    @VisibleForTesting
    @GuardedBy("mLock")
    final Map<IBinder, InputDeviceDescriptor> mInputDeviceDescriptors = new ArrayMap<>();

    private final Handler mHandler;
    private final NativeWrapper mNativeWrapper;
    private final DisplayManagerInternal mDisplayManagerInternal;
    private final InputManagerInternal mInputManagerInternal;
    private final WindowManager mWindowManager;
    private final DeviceCreationThreadVerifier mThreadVerifier;

    InputController(@NonNull Object lock, @NonNull Handler handler,
            @NonNull WindowManager windowManager) {
        this(lock, new NativeWrapper(), handler, windowManager,
                // Verify that virtual devices are not created on the handler thread.
                () -> !handler.getLooper().isCurrentThread());
    }

    @VisibleForTesting
    InputController(@NonNull Object lock, @NonNull NativeWrapper nativeWrapper,
            @NonNull Handler handler, @NonNull WindowManager windowManager,
            @NonNull DeviceCreationThreadVerifier threadVerifier) {
        mLock = lock;
        mHandler = handler;
        mNativeWrapper = nativeWrapper;
        mDisplayManagerInternal = LocalServices.getService(DisplayManagerInternal.class);
        mInputManagerInternal = LocalServices.getService(InputManagerInternal.class);
        mWindowManager = windowManager;
        mThreadVerifier = threadVerifier;
    }

    void close() {
        synchronized (mLock) {
            final Iterator<Map.Entry<IBinder, InputDeviceDescriptor>> iterator =
                    mInputDeviceDescriptors.entrySet().iterator();
            if (iterator.hasNext()) {
                final Map.Entry<IBinder, InputDeviceDescriptor> entry = iterator.next();
                final IBinder token = entry.getKey();
                final InputDeviceDescriptor inputDeviceDescriptor = entry.getValue();
                iterator.remove();
                closeInputDeviceDescriptorLocked(token, inputDeviceDescriptor);
            }
        }
    }

    void createKeyboard(@NonNull String deviceName,
            int vendorId,
            int productId,
            @NonNull IBinder deviceToken,
            int displayId) {
        final String phys = createPhys(PHYS_TYPE_KEYBOARD);
        try {
            createDeviceInternal(InputDeviceDescriptor.TYPE_KEYBOARD, deviceName, vendorId,
                    productId, deviceToken, displayId, phys,
                    () -> mNativeWrapper.openUinputKeyboard(deviceName, vendorId, productId, phys));
        } catch (DeviceCreationException e) {
            throw new RuntimeException(
                    "Failed to create virtual keyboard device '" + deviceName + "'.", e);
        }
    }

    void createMouse(@NonNull String deviceName,
            int vendorId,
            int productId,
            @NonNull IBinder deviceToken,
            int displayId) {
        final String phys = createPhys(PHYS_TYPE_MOUSE);
        try {
            createDeviceInternal(InputDeviceDescriptor.TYPE_MOUSE, deviceName, vendorId, productId,
                    deviceToken, displayId, phys,
                    () -> mNativeWrapper.openUinputMouse(deviceName, vendorId, productId, phys));
        } catch (DeviceCreationException e) {
            throw new RuntimeException(
                    "Failed to create virtual mouse device: '" + deviceName + "'.", e);
        }
        mInputManagerInternal.setVirtualMousePointerDisplayId(displayId);
    }

    void createTouchscreen(@NonNull String deviceName,
            int vendorId,
            int productId,
            @NonNull IBinder deviceToken,
            int displayId,
            @NonNull Point screenSize) {
        final String phys = createPhys(PHYS_TYPE_TOUCHSCREEN);
        try {
            createDeviceInternal(InputDeviceDescriptor.TYPE_TOUCHSCREEN, deviceName, vendorId,
                    productId, deviceToken, displayId, phys,
                    () -> mNativeWrapper.openUinputTouchscreen(deviceName, vendorId, productId,
                            phys, screenSize.y, screenSize.x));
        } catch (DeviceCreationException e) {
            throw new RuntimeException(
                    "Failed to create virtual touchscreen device '" + deviceName + "'.", e);
        }
    }

    void unregisterInputDevice(@NonNull IBinder token) {
        synchronized (mLock) {
            final InputDeviceDescriptor inputDeviceDescriptor = mInputDeviceDescriptors.remove(
                    token);
            if (inputDeviceDescriptor == null) {
                throw new IllegalArgumentException(
                        "Could not unregister input device for given token");
            }
            closeInputDeviceDescriptorLocked(token, inputDeviceDescriptor);
        }
    }

    @GuardedBy("mLock")
    private void closeInputDeviceDescriptorLocked(IBinder token,
            InputDeviceDescriptor inputDeviceDescriptor) {
        token.unlinkToDeath(inputDeviceDescriptor.getDeathRecipient(), /* flags= */ 0);
        mNativeWrapper.closeUinput(inputDeviceDescriptor.getFileDescriptor());
        InputManager.getInstance().removeUniqueIdAssociation(inputDeviceDescriptor.getPhys());

        // Reset values to the default if all virtual mice are unregistered, or set display
        // id if there's another mouse (choose the most recent). The inputDeviceDescriptor must be
        // removed from the mInputDeviceDescriptors instance variable prior to this point.
        if (inputDeviceDescriptor.isMouse()) {
            if (mInputManagerInternal.getVirtualMousePointerDisplayId()
                    == inputDeviceDescriptor.getDisplayId()) {
                updateActivePointerDisplayIdLocked();
            }
        }
    }

    void setShowPointerIcon(boolean visible, int displayId) {
        mInputManagerInternal.setPointerIconVisible(visible, displayId);
    }

    void setPointerAcceleration(float pointerAcceleration, int displayId) {
        mInputManagerInternal.setPointerAcceleration(pointerAcceleration, displayId);
    }

    void setDisplayEligibilityForPointerCapture(boolean isEligible, int displayId) {
        mInputManagerInternal.setDisplayEligibilityForPointerCapture(displayId, isEligible);
    }

    void setLocalIme(int displayId) {
        // WM throws a SecurityException if the display is untrusted.
        if ((mDisplayManagerInternal.getDisplayInfo(displayId).flags & Display.FLAG_TRUSTED)
                == Display.FLAG_TRUSTED) {
            mWindowManager.setDisplayImePolicy(displayId,
                    WindowManager.DISPLAY_IME_POLICY_LOCAL);
        }
    }

    @GuardedBy("mLock")
    private void updateActivePointerDisplayIdLocked() {
        InputDeviceDescriptor mostRecentlyCreatedMouse = null;
        for (InputDeviceDescriptor otherInputDeviceDescriptor : mInputDeviceDescriptors.values()) {
            if (otherInputDeviceDescriptor.isMouse()) {
                if (mostRecentlyCreatedMouse == null
                        || (otherInputDeviceDescriptor.getCreationOrderNumber()
                        > mostRecentlyCreatedMouse.getCreationOrderNumber())) {
                    mostRecentlyCreatedMouse = otherInputDeviceDescriptor;
                }
            }
        }
        if (mostRecentlyCreatedMouse != null) {
            mInputManagerInternal.setVirtualMousePointerDisplayId(
                    mostRecentlyCreatedMouse.getDisplayId());
        } else {
            // All mice have been unregistered
            mInputManagerInternal.setVirtualMousePointerDisplayId(Display.INVALID_DISPLAY);
        }
    }

    private static String createPhys(@PhysType String type) {
        return String.format("virtual%s:%d", type, sNextPhysId.getAndIncrement());
    }

    private void setUniqueIdAssociation(int displayId, String phys) {
        final String displayUniqueId = mDisplayManagerInternal.getDisplayInfo(displayId).uniqueId;
        InputManager.getInstance().addUniqueIdAssociation(phys, displayUniqueId);
    }

    boolean sendKeyEvent(@NonNull IBinder token, @NonNull VirtualKeyEvent event) {
        synchronized (mLock) {
            final InputDeviceDescriptor inputDeviceDescriptor = mInputDeviceDescriptors.get(
                    token);
            if (inputDeviceDescriptor == null) {
                throw new IllegalArgumentException(
                        "Could not send key event to input device for given token");
            }
            return mNativeWrapper.writeKeyEvent(inputDeviceDescriptor.getFileDescriptor(),
                    event.getKeyCode(), event.getAction());
        }
    }

    boolean sendButtonEvent(@NonNull IBinder token, @NonNull VirtualMouseButtonEvent event) {
        synchronized (mLock) {
            final InputDeviceDescriptor inputDeviceDescriptor = mInputDeviceDescriptors.get(
                    token);
            if (inputDeviceDescriptor == null) {
                throw new IllegalArgumentException(
                        "Could not send button event to input device for given token");
            }
            if (inputDeviceDescriptor.getDisplayId()
                    != mInputManagerInternal.getVirtualMousePointerDisplayId()) {
                throw new IllegalStateException(
                        "Display id associated with this mouse is not currently targetable");
            }
            return mNativeWrapper.writeButtonEvent(inputDeviceDescriptor.getFileDescriptor(),
                    event.getButtonCode(), event.getAction());
        }
    }

    boolean sendTouchEvent(@NonNull IBinder token, @NonNull VirtualTouchEvent event) {
        synchronized (mLock) {
            final InputDeviceDescriptor inputDeviceDescriptor = mInputDeviceDescriptors.get(
                    token);
            if (inputDeviceDescriptor == null) {
                throw new IllegalArgumentException(
                        "Could not send touch event to input device for given token");
            }
            return mNativeWrapper.writeTouchEvent(inputDeviceDescriptor.getFileDescriptor(),
                    event.getPointerId(), event.getToolType(), event.getAction(), event.getX(),
                    event.getY(), event.getPressure(), event.getMajorAxisSize());
        }
    }

    boolean sendRelativeEvent(@NonNull IBinder token, @NonNull VirtualMouseRelativeEvent event) {
        synchronized (mLock) {
            final InputDeviceDescriptor inputDeviceDescriptor = mInputDeviceDescriptors.get(
                    token);
            if (inputDeviceDescriptor == null) {
                throw new IllegalArgumentException(
                        "Could not send relative event to input device for given token");
            }
            if (inputDeviceDescriptor.getDisplayId()
                    != mInputManagerInternal.getVirtualMousePointerDisplayId()) {
                throw new IllegalStateException(
                        "Display id associated with this mouse is not currently targetable");
            }
            return mNativeWrapper.writeRelativeEvent(inputDeviceDescriptor.getFileDescriptor(),
                    event.getRelativeX(), event.getRelativeY());
        }
    }

    boolean sendScrollEvent(@NonNull IBinder token, @NonNull VirtualMouseScrollEvent event) {
        synchronized (mLock) {
            final InputDeviceDescriptor inputDeviceDescriptor = mInputDeviceDescriptors.get(
                    token);
            if (inputDeviceDescriptor == null) {
                throw new IllegalArgumentException(
                        "Could not send scroll event to input device for given token");
            }
            if (inputDeviceDescriptor.getDisplayId()
                    != mInputManagerInternal.getVirtualMousePointerDisplayId()) {
                throw new IllegalStateException(
                        "Display id associated with this mouse is not currently targetable");
            }
            return mNativeWrapper.writeScrollEvent(inputDeviceDescriptor.getFileDescriptor(),
                    event.getXAxisMovement(), event.getYAxisMovement());
        }
    }

    public PointF getCursorPosition(@NonNull IBinder token) {
        synchronized (mLock) {
            final InputDeviceDescriptor inputDeviceDescriptor = mInputDeviceDescriptors.get(
                    token);
            if (inputDeviceDescriptor == null) {
                throw new IllegalArgumentException(
                        "Could not get cursor position for input device for given token");
            }
            if (inputDeviceDescriptor.getDisplayId()
                    != mInputManagerInternal.getVirtualMousePointerDisplayId()) {
                throw new IllegalStateException(
                        "Display id associated with this mouse is not currently targetable");
            }
            return LocalServices.getService(InputManagerInternal.class).getCursorPosition();
        }
    }

    public void dump(@NonNull PrintWriter fout) {
        fout.println("    InputController: ");
        synchronized (mLock) {
            fout.println("      Active descriptors: ");
            for (InputDeviceDescriptor inputDeviceDescriptor : mInputDeviceDescriptors.values()) {
                fout.println("        fd: " + inputDeviceDescriptor.getFileDescriptor());
                fout.println("          displayId: " + inputDeviceDescriptor.getDisplayId());
                fout.println("          creationOrder: "
                        + inputDeviceDescriptor.getCreationOrderNumber());
                fout.println("          type: " + inputDeviceDescriptor.getType());
                fout.println("          phys: " + inputDeviceDescriptor.getPhys());
            }
        }
    }

    private static native int nativeOpenUinputKeyboard(String deviceName, int vendorId,
            int productId, String phys);
    private static native int nativeOpenUinputMouse(String deviceName, int vendorId, int productId,
            String phys);
    private static native int nativeOpenUinputTouchscreen(String deviceName, int vendorId,
            int productId, String phys, int height, int width);
    private static native boolean nativeCloseUinput(int fd);
    private static native boolean nativeWriteKeyEvent(int fd, int androidKeyCode, int action);
    private static native boolean nativeWriteButtonEvent(int fd, int buttonCode, int action);
    private static native boolean nativeWriteTouchEvent(int fd, int pointerId, int toolType,
            int action, float locationX, float locationY, float pressure, float majorAxisSize);
    private static native boolean nativeWriteRelativeEvent(int fd, float relativeX,
            float relativeY);
    private static native boolean nativeWriteScrollEvent(int fd, float xAxisMovement,
            float yAxisMovement);

    /** Wrapper around the static native methods for tests. */
    @VisibleForTesting
    protected static class NativeWrapper {
        public int openUinputKeyboard(String deviceName, int vendorId, int productId, String phys) {
            return nativeOpenUinputKeyboard(deviceName, vendorId, productId, phys);
        }

        public int openUinputMouse(String deviceName, int vendorId, int productId, String phys) {
            return nativeOpenUinputMouse(deviceName, vendorId, productId, phys);
        }

        public int openUinputTouchscreen(String deviceName, int vendorId,
                int productId, String phys, int height, int width) {
            return nativeOpenUinputTouchscreen(deviceName, vendorId, productId, phys, height,
                    width);
        }

        public boolean closeUinput(int fd) {
            return nativeCloseUinput(fd);
        }

        public boolean writeKeyEvent(int fd, int androidKeyCode, int action) {
            return nativeWriteKeyEvent(fd, androidKeyCode, action);
        }

        public boolean writeButtonEvent(int fd, int buttonCode, int action) {
            return nativeWriteButtonEvent(fd, buttonCode, action);
        }

        public boolean writeTouchEvent(int fd, int pointerId, int toolType, int action,
                float locationX, float locationY, float pressure, float majorAxisSize) {
            return nativeWriteTouchEvent(fd, pointerId, toolType,
                    action, locationX, locationY,
                    pressure, majorAxisSize);
        }

        public boolean writeRelativeEvent(int fd, float relativeX, float relativeY) {
            return nativeWriteRelativeEvent(fd, relativeX, relativeY);
        }

        public boolean writeScrollEvent(int fd, float xAxisMovement, float yAxisMovement) {
            return nativeWriteScrollEvent(fd, xAxisMovement,
                    yAxisMovement);
        }
    }

    @VisibleForTesting static final class InputDeviceDescriptor {

        static final int TYPE_KEYBOARD = 1;
        static final int TYPE_MOUSE = 2;
        static final int TYPE_TOUCHSCREEN = 3;
        @IntDef(prefix = { "TYPE_" }, value = {
                TYPE_KEYBOARD,
                TYPE_MOUSE,
                TYPE_TOUCHSCREEN,
        })
        @Retention(RetentionPolicy.SOURCE)
        @interface Type {
        }

        private static final AtomicLong sNextCreationOrderNumber = new AtomicLong(1);

        private final int mFd;
        private final IBinder.DeathRecipient mDeathRecipient;
        private final @Type int mType;
        private final int mDisplayId;
        private final String mPhys;
        // Monotonically increasing number; devices with lower numbers were created earlier.
        private final long mCreationOrderNumber;

        InputDeviceDescriptor(int fd, IBinder.DeathRecipient deathRecipient, @Type int type,
                int displayId, String phys) {
            mFd = fd;
            mDeathRecipient = deathRecipient;
            mType = type;
            mDisplayId = displayId;
            mPhys = phys;
            mCreationOrderNumber = sNextCreationOrderNumber.getAndIncrement();
        }

        public int getFileDescriptor() {
            return mFd;
        }

        public int getType() {
            return mType;
        }

        public boolean isMouse() {
            return mType == TYPE_MOUSE;
        }

        public IBinder.DeathRecipient getDeathRecipient() {
            return mDeathRecipient;
        }

        public int getDisplayId() {
            return mDisplayId;
        }

        public long getCreationOrderNumber() {
            return mCreationOrderNumber;
        }

        public String getPhys() {
            return mPhys;
        }
    }

    private final class BinderDeathRecipient implements IBinder.DeathRecipient {

        private final IBinder mDeviceToken;

        BinderDeathRecipient(IBinder deviceToken) {
            mDeviceToken = deviceToken;
        }

        @Override
        public void binderDied() {
            // All callers are expected to call {@link VirtualDevice#unregisterInputDevice} before
            // quitting, which removes this death recipient. If this is invoked, the remote end
            // died, or they disposed of the object without properly unregistering.
            Slog.e(TAG, "Virtual input controller binder died");
            unregisterInputDevice(mDeviceToken);
        }
    }

    /** A helper class used to wait for an input device to be registered. */
    private class WaitForDevice implements AutoCloseable {
        private final CountDownLatch mDeviceAddedLatch = new CountDownLatch(1);
        private final InputManager.InputDeviceListener mListener;

        WaitForDevice(String deviceName, int vendorId, int productId) {
            mListener = new InputManager.InputDeviceListener() {
                @Override
                public void onInputDeviceAdded(int deviceId) {
                    final InputDevice device = InputManager.getInstance().getInputDevice(
                            deviceId);
                    Objects.requireNonNull(device, "Newly added input device was null.");
                    if (!device.getName().equals(deviceName)) {
                        return;
                    }
                    final InputDeviceIdentifier id = device.getIdentifier();
                    if (id.getVendorId() != vendorId || id.getProductId() != productId) {
                        return;
                    }
                    mDeviceAddedLatch.countDown();
                }

                @Override
                public void onInputDeviceRemoved(int deviceId) {

                }

                @Override
                public void onInputDeviceChanged(int deviceId) {

                }
            };
            InputManager.getInstance().registerInputDeviceListener(mListener, mHandler);
        }

        /** Note: This must not be called from {@link #mHandler}'s thread. */
        void waitForDeviceCreation() throws DeviceCreationException {
            try {
                if (!mDeviceAddedLatch.await(1, TimeUnit.MINUTES)) {
                    throw new DeviceCreationException(
                            "Timed out waiting for virtual device to be created.");
                }
            } catch (InterruptedException e) {
                throw new DeviceCreationException(
                        "Interrupted while waiting for virtual device to be created.", e);
            }
        }

        @Override
        public void close() {
            InputManager.getInstance().unregisterInputDeviceListener(mListener);
        }
    }

    /** An internal exception that is thrown to indicate an error when opening a virtual device. */
    private static class DeviceCreationException extends Exception {
        DeviceCreationException(String message) {
            super(message);
        }
        DeviceCreationException(String message, Exception cause) {
            super(message, cause);
        }
    }

    /**
     * Creates a virtual input device synchronously, and waits for the notification that the device
     * was added.
     *
     * Note: Input device creation is expected to happen on a binder thread, and the calling thread
     * will be blocked until the input device creation is successful. This should not be called on
     * the handler's thread.
     *
     * @throws DeviceCreationException Throws this exception if anything unexpected happens in the
     *                                 process of creating the device. This method will take care
     *                                 to restore the state of the system in the event of any
     *                                 unexpected behavior.
     */
    private void createDeviceInternal(@InputDeviceDescriptor.Type int type, String deviceName,
            int vendorId, int productId, IBinder deviceToken, int displayId, String phys,
            Supplier<Integer> deviceOpener)
            throws DeviceCreationException {
        if (!mThreadVerifier.isValidThread()) {
            throw new IllegalStateException(
                    "Virtual device creation should happen on an auxiliary thread (e.g. binder "
                            + "thread) and not from the handler's thread.");
        }

        final int fd;
        final BinderDeathRecipient binderDeathRecipient;

        setUniqueIdAssociation(displayId, phys);
        try (WaitForDevice waiter = new WaitForDevice(deviceName, vendorId, productId)) {
            fd = deviceOpener.get();
            if (fd < 0) {
                throw new DeviceCreationException(
                        "A native error occurred when creating touchscreen: " + -fd);
            }
            // The fd is valid from here, so ensure that all failures close the fd after this point.
            try {
                waiter.waitForDeviceCreation();

                binderDeathRecipient = new BinderDeathRecipient(deviceToken);
                try {
                    deviceToken.linkToDeath(binderDeathRecipient, /* flags= */ 0);
                } catch (RemoteException e) {
                    throw new DeviceCreationException(
                            "Client died before virtual device could be created.", e);
                }
            } catch (DeviceCreationException e) {
                mNativeWrapper.closeUinput(fd);
                throw e;
            }
        } catch (DeviceCreationException e) {
            InputManager.getInstance().removeUniqueIdAssociation(phys);
            throw e;
        }

        synchronized (mLock) {
            mInputDeviceDescriptors.put(deviceToken,
                    new InputDeviceDescriptor(fd, binderDeathRecipient, type, displayId, phys));
        }
    }

    @VisibleForTesting
    interface DeviceCreationThreadVerifier {
        /** Returns true if the calling thread is a valid thread for device creation. */
        boolean isValidThread();
    }
}