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Commit f4f91bef authored by Piotr Wilczyński's avatar Piotr Wilczyński
Browse files

Limit the number of virtual displays 

- general limit
- limit per package

Bug: 261791612
Flag: com.android.server.display.feature.flags.virtual_display_limit
Test: atest DisplayManagerServiceTest
Test: atest VirtualDisplayAdapterTest
Change-Id: I284e1a7a17934e1c8d3ba5ca1ddf6504f8adfe49
parent 0fc279fb

core/res/res/values/config.xml

+8 −0
Original line number Diff line number Diff line
@@ -6916,6 +6916,14 @@ 
         entering the corresponding modes -->

    <string name="config_rearDisplayPhysicalAddress" translatable="false"></string>



    <!-- The maximum number of virtual displays that can exist at the same time.

         It must be >= 1. -->

    <integer name="config_virtualDisplayLimit">100</integer>



    <!-- The maximum number of virtual displays per package that can exist at the same time.

         It must be >= 1. -->

    <integer name="config_virtualDisplayLimitPerPackage">50</integer>



    <!-- List of certificate to be used for font fs-verity integrity verification -->

    <string-array translatable="false" name="config_fontManagerServiceCerts">

    </string-array>

core/res/res/values/symbols.xml

+3 −0
Original line number Diff line number Diff line
@@ -5242,6 +5242,9 @@ 
  <java-symbol type="integer" name="config_deviceStateConcurrentRearDisplay" />

  <java-symbol type="string" name="config_rearDisplayPhysicalAddress" />



  <java-symbol type="integer" name="config_virtualDisplayLimit" />

  <java-symbol type="integer" name="config_virtualDisplayLimitPerPackage" />



  <!-- For app language picker -->

  <java-symbol type="string" name="system_locale_title" />

  <java-symbol type="layout" name="app_language_picker_system_default" />

services/core/java/com/android/server/display/DisplayManagerService.java

+6 −5
Original line number Diff line number Diff line
@@ -1960,7 +1960,7 @@ public final class DisplayManagerService extends SystemService { 
                        // handles stopping the projection.

                        Slog.w(TAG, "Content Recording: failed to start mirroring - "

                                + "releasing virtual display " + displayId);

                        releaseVirtualDisplayInternal(callback.asBinder());

                        releaseVirtualDisplayInternal(callback.asBinder(), callingUid);

                        return Display.INVALID_DISPLAY;

                    } else if (projection != null) {

                        // Indicate that this projection has been used to record, and can't be used
@@ -2049,7 +2049,7 @@ public final class DisplayManagerService extends SystemService { 
        // Something weird happened and the logical display was not created.

        Slog.w(TAG, "Rejecting request to create virtual display "

                + "because the logical display was not created.");

        mVirtualDisplayAdapter.releaseVirtualDisplayLocked(callback.asBinder());

        mVirtualDisplayAdapter.releaseVirtualDisplayLocked(callback.asBinder(), callingUid);

        mDisplayDeviceRepo.onDisplayDeviceEvent(device,

                DisplayAdapter.DISPLAY_DEVICE_EVENT_REMOVED);

        return -1;
@@ -2076,14 +2076,14 @@ public final class DisplayManagerService extends SystemService { 
        }

    }



    private void releaseVirtualDisplayInternal(IBinder appToken) {

    private void releaseVirtualDisplayInternal(IBinder appToken, int callingUid) {

        synchronized (mSyncRoot) {

            if (mVirtualDisplayAdapter == null) {

                return;

            }



            DisplayDevice device =

                    mVirtualDisplayAdapter.releaseVirtualDisplayLocked(appToken);

                    mVirtualDisplayAdapter.releaseVirtualDisplayLocked(appToken, callingUid);

            Slog.d(TAG, "Virtual Display: Display Device released");

            if (device != null) {

                // TODO: multi-display - handle virtual displays the same as other display adapters.
@@ -4606,9 +4606,10 @@ public final class DisplayManagerService extends SystemService { 


        @Override // Binder call

        public void releaseVirtualDisplay(IVirtualDisplayCallback callback) {

            final int callingUid = Binder.getCallingUid();

            final long token = Binder.clearCallingIdentity();

            try {

                releaseVirtualDisplayInternal(callback.asBinder());

                releaseVirtualDisplayInternal(callback.asBinder(), callingUid);

            } finally {

                Binder.restoreCallingIdentity(token);

            }

services/core/java/com/android/server/display/VirtualDisplayAdapter.java

+72 −8
Original line number Diff line number Diff line
@@ -55,12 +55,14 @@ import android.os.RemoteException; 
import android.os.SystemProperties;

import android.util.ArrayMap;

import android.util.Slog;

import android.util.SparseIntArray;

import android.view.Display;

import android.view.DisplayCutout;

import android.view.DisplayShape;

import android.view.Surface;

import android.view.SurfaceControl;



import com.android.internal.R;

import com.android.internal.annotations.VisibleForTesting;

import com.android.server.display.feature.DisplayManagerFlags;
@@ -85,6 +87,11 @@ public class VirtualDisplayAdapter extends DisplayAdapter { 
    private static final AtomicInteger sNextUniqueIndex = new AtomicInteger(0);



    private final ArrayMap<IBinder, VirtualDisplayDevice> mVirtualDisplayDevices = new ArrayMap<>();



    private final int mMaxDevices;

    private final int mMaxDevicesPerPackage;

    private final SparseIntArray mNoOfDevicesPerPackage = new SparseIntArray();



    private final Handler mHandler;

    private final SurfaceControlDisplayFactory mSurfaceControlDisplayFactory;
@@ -114,8 +121,31 @@ public class VirtualDisplayAdapter extends DisplayAdapter { 
        super(syncRoot, context, handler, listener, TAG, featureFlags);

        mHandler = handler;

        mSurfaceControlDisplayFactory = surfaceControlDisplayFactory;



        mMaxDevices = context.getResources().getInteger(R.integer.config_virtualDisplayLimit);

        if (mMaxDevices < 1) {

            throw new IllegalArgumentException("The limit of virtual displays must be >= 1");

        }

        mMaxDevicesPerPackage =

                context.getResources().getInteger(R.integer.config_virtualDisplayLimitPerPackage);

        if (mMaxDevicesPerPackage < 1) {

            throw new IllegalArgumentException(

                    "The limit of virtual displays per package must be >= 1");

        }

    }



    /**

     * Create a virtual display

     * @param callback The callback

     * @param projection The media projection

     * @param ownerUid The UID of the package creating a display

     * @param ownerPackageName The name of the package creating a display

     * @param uniqueId The unique ID of the display device

     * @param surface The surface

     * @param flags The flags

     * @param virtualDisplayConfig The config

     * @return The display device created

     */

    public DisplayDevice createVirtualDisplayLocked(IVirtualDisplayCallback callback,

            IMediaProjection projection, int ownerUid, String ownerPackageName, String uniqueId,

            Surface surface, int flags, VirtualDisplayConfig virtualDisplayConfig) {
@@ -126,6 +156,22 @@ public class VirtualDisplayAdapter extends DisplayAdapter { 
            return null;

        }



        if (getFeatureFlags().isVirtualDisplayLimitEnabled()

                && mVirtualDisplayDevices.size() >= mMaxDevices) {

            Slog.w(TAG, "Rejecting request to create private virtual display because "

                    + mMaxDevices + " devices already exist.");

            return null;

        }



        int noOfDevices = mNoOfDevicesPerPackage.get(ownerUid, /* valueIfKeyNotFound= */ 0);

        if (getFeatureFlags().isVirtualDisplayLimitEnabled()

                && noOfDevices >= mMaxDevicesPerPackage) {

            Slog.w(TAG, "Rejecting request to create private virtual display because "

                    + mMaxDevicesPerPackage + " devices already exist for package "

                    + ownerPackageName + ".");

            return null;

        }



        String name = virtualDisplayConfig.getName();

        boolean secure = (flags & VIRTUAL_DISPLAY_FLAG_SECURE) != 0;
@@ -140,6 +186,9 @@ public class VirtualDisplayAdapter extends DisplayAdapter { 
                projection, mediaProjectionCallback, uniqueId, virtualDisplayConfig);



        mVirtualDisplayDevices.put(appToken, device);

        if (getFeatureFlags().isVirtualDisplayLimitEnabled()) {

            mNoOfDevicesPerPackage.put(ownerUid, noOfDevices + 1);

        }



        try {

            if (projection != null) {
@@ -150,7 +199,7 @@ public class VirtualDisplayAdapter extends DisplayAdapter { 
            appToken.linkToDeath(device, 0);

        } catch (RemoteException ex) {

            Slog.e(TAG, "Virtual Display: error while setting up VirtualDisplayDevice", ex);

            mVirtualDisplayDevices.remove(appToken);

            removeVirtualDisplayDeviceLocked(appToken, ownerUid);

            device.destroyLocked(false);

            return null;

        }
@@ -194,8 +243,15 @@ public class VirtualDisplayAdapter extends DisplayAdapter { 
        }

    }



    public DisplayDevice releaseVirtualDisplayLocked(IBinder appToken) {

        VirtualDisplayDevice device = mVirtualDisplayDevices.remove(appToken);

    /**

     * Release a virtual display that was previously created

     * @param appToken The token to identify the display

     * @param ownerUid The UID of the package, used to keep track of and limit the number of

     *                 displays created per package

     * @return The display device that has been removed

     */

    public DisplayDevice releaseVirtualDisplayLocked(IBinder appToken, int ownerUid) {

        VirtualDisplayDevice device = removeVirtualDisplayDeviceLocked(appToken, ownerUid);

        if (device != null) {

            Slog.v(TAG, "Release VirtualDisplay " + device.mName);

            device.destroyLocked(true);
@@ -235,10 +291,6 @@ public class VirtualDisplayAdapter extends DisplayAdapter { 
                : ("," + uid + "," + config.getName() + "," + sNextUniqueIndex.getAndIncrement()));

    }



    private void handleBinderDiedLocked(IBinder appToken) {

        mVirtualDisplayDevices.remove(appToken);

    }



    private void handleMediaProjectionStoppedLocked(IBinder appToken) {

        VirtualDisplayDevice device = mVirtualDisplayDevices.get(appToken);

        if (device != null) {
@@ -248,6 +300,18 @@ public class VirtualDisplayAdapter extends DisplayAdapter { 
        }

    }



    private VirtualDisplayDevice removeVirtualDisplayDeviceLocked(IBinder appToken, int ownerUid) {

        int noOfDevices = mNoOfDevicesPerPackage.get(ownerUid, /* valueIfKeyNotFound= */ 0);

        if (getFeatureFlags().isVirtualDisplayLimitEnabled()) {

            if (noOfDevices <= 1) {

                mNoOfDevicesPerPackage.delete(ownerUid);

            } else {

                mNoOfDevicesPerPackage.put(ownerUid, noOfDevices - 1);

            }

        }

        return mVirtualDisplayDevices.remove(appToken);

    }



    private final class VirtualDisplayDevice extends DisplayDevice implements DeathRecipient {

        private static final int PENDING_SURFACE_CHANGE = 0x01;

        private static final int PENDING_RESIZE = 0x02;
@@ -309,7 +373,7 @@ public class VirtualDisplayAdapter extends DisplayAdapter { 
        @Override

        public void binderDied() {

            synchronized (getSyncRoot()) {

                handleBinderDiedLocked(mAppToken);

                removeVirtualDisplayDeviceLocked(mAppToken, mOwnerUid);

                Slog.i(TAG, "Virtual display device released because application token died: "

                    + mOwnerPackageName);

                destroyLocked(false);

services/core/java/com/android/server/display/feature/DisplayManagerFlags.java

+10 −0
Original line number Diff line number Diff line
@@ -199,6 +199,11 @@ public class DisplayManagerFlags { 
            Flags.FLAG_IDLE_SCREEN_CONFIG_IN_SUBSCRIBING_LIGHT_SENSOR,

            Flags::idleScreenConfigInSubscribingLightSensor);



    private final FlagState mVirtualDisplayLimit =

            new FlagState(

                    Flags.FLAG_VIRTUAL_DISPLAY_LIMIT,

                    Flags::virtualDisplayLimit);



    private final FlagState mNormalBrightnessForDozeParameter = new FlagState(

            Flags.FLAG_NORMAL_BRIGHTNESS_FOR_DOZE_PARAMETER,

            Flags::normalBrightnessForDozeParameter
@@ -412,6 +417,10 @@ public class DisplayManagerFlags { 
        return mNewHdrBrightnessModifier.isEnabled();

    }



    public boolean isVirtualDisplayLimitEnabled() {

        return mVirtualDisplayLimit.isEnabled();

    }



    /**

     * @return Whether the useDozeBrightness parameter should be used

     */
@@ -476,6 +485,7 @@ public class DisplayManagerFlags { 
        pw.println(" " + mOffloadDozeOverrideHoldsWakelock);

        pw.println(" " + mOffloadSessionCancelBlockScreenOn);

        pw.println(" " + mNewHdrBrightnessModifier);

        pw.println(" " + mVirtualDisplayLimit);

        pw.println(" " + mNormalBrightnessForDozeParameter);

        pw.println(" " + mIdleScreenConfigInSubscribingLightSensor);

        pw.println(" " + mEnableBatteryStatsForAllDisplays);