/*
* Copyright (C) 2016 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.tv;
import android.Manifest;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.content.pm.ServiceInfo;
import android.os.Handler;
import android.os.UserHandle;
import android.util.Log;
import android.util.Slog;
import java.util.ArrayList;
import java.util.Collections;
/**
* Watches for emote provider services to be installed.
* Adds a provider for each registered service.
*
* @see TvRemoteProviderProxy
*/
final class TvRemoteProviderWatcher {
private static final String TAG = "TvRemoteProvWatcher"; // max. 23 chars
private static final boolean DEBUG = Log.isLoggable(TAG, Log.VERBOSE);
private final Context mContext;
private final ProviderMethods mProvider;
private final Handler mHandler;
private final PackageManager mPackageManager;
private final ArrayList<TvRemoteProviderProxy> mProviderProxies = new ArrayList<>();
private final int mUserId;
private final String mUnbundledServicePackage;
private boolean mRunning;
public TvRemoteProviderWatcher(Context context, ProviderMethods provider, Handler handler) {
mContext = context;
mProvider = provider;
mHandler = handler;
mUserId = UserHandle.myUserId();
mPackageManager = context.getPackageManager();
mUnbundledServicePackage = context.getString(
com.android.internal.R.string.config_tvRemoteServicePackage);
}
public void start() {
if (DEBUG) Slog.d(TAG, "start()");
if (!mRunning) {
mRunning = true;
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_PACKAGE_ADDED);
filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
filter.addAction(Intent.ACTION_PACKAGE_CHANGED);
filter.addAction(Intent.ACTION_PACKAGE_REPLACED);
filter.addAction(Intent.ACTION_PACKAGE_RESTARTED);
filter.addDataScheme("package");
mContext.registerReceiverAsUser(mScanPackagesReceiver,
new UserHandle(mUserId), filter, null, mHandler);
// Scan packages.
// Also has the side-effect of restarting providers if needed.
mHandler.post(mScanPackagesRunnable);
}
}
public void stop() {
if (mRunning) {
mRunning = false;
mContext.unregisterReceiver(mScanPackagesReceiver);
mHandler.removeCallbacks(mScanPackagesRunnable);
// Stop all providers.
for (int i = mProviderProxies.size() - 1; i >= 0; i--) {
mProviderProxies.get(i).stop();
}
}
}
private void scanPackages() {
if (!mRunning) {
return;
}
if (DEBUG) Log.d(TAG, "scanPackages()");
// Add providers for all new services.
// Reorder the list so that providers left at the end will be the ones to remove.
int targetIndex = 0;
Intent intent = new Intent(TvRemoteProviderProxy.SERVICE_INTERFACE);
for (ResolveInfo resolveInfo : mPackageManager.queryIntentServicesAsUser(
intent, 0, mUserId)) {
ServiceInfo serviceInfo = resolveInfo.serviceInfo;
if (serviceInfo != null && verifyServiceTrusted(serviceInfo)) {
int sourceIndex = findProvider(serviceInfo.packageName, serviceInfo.name);
if (sourceIndex < 0) {
TvRemoteProviderProxy providerProxy =
new TvRemoteProviderProxy(mContext,
new ComponentName(serviceInfo.packageName, serviceInfo.name),
mUserId, serviceInfo.applicationInfo.uid);
providerProxy.start();
mProviderProxies.add(targetIndex++, providerProxy);
mProvider.addProvider(providerProxy);
} else if (sourceIndex >= targetIndex) {
TvRemoteProviderProxy provider = mProviderProxies.get(sourceIndex);
provider.start(); // restart the provider if needed
provider.rebindIfDisconnected();
Collections.swap(mProviderProxies, sourceIndex, targetIndex++);
}
}
}
if (DEBUG) Log.d(TAG, "scanPackages() targetIndex " + targetIndex);
// Remove providers for missing services.
if (targetIndex < mProviderProxies.size()) {
for (int i = mProviderProxies.size() - 1; i >= targetIndex; i--) {
TvRemoteProviderProxy providerProxy = mProviderProxies.get(i);
mProvider.removeProvider(providerProxy);
mProviderProxies.remove(providerProxy);
providerProxy.stop();
}
}
}
private boolean verifyServiceTrusted(ServiceInfo serviceInfo) {
if (serviceInfo.permission == null || !serviceInfo.permission.equals(
Manifest.permission.BIND_TV_REMOTE_SERVICE)) {
// If the service does not require this permission then any app could
// potentially bind to it and cause the atv remote provider service to
// misbehave. So we only want to trust providers that require the
// correct permissions.
Slog.w(TAG, "Ignoring atv remote provider service because it did not "
+ "require the BIND_TV_REMOTE_SERVICE permission in its manifest: "
+ serviceInfo.packageName + "/" + serviceInfo.name);
return false;
}
// Check if package name is white-listed here.
if (!serviceInfo.packageName.equals(mUnbundledServicePackage)) {
Slog.w(TAG, "Ignoring atv remote provider service because the package has not "
+ "been set and/or whitelisted: "
+ serviceInfo.packageName + "/" + serviceInfo.name);
return false;
}
if (!hasNecessaryPermissions(serviceInfo.packageName)) {
// If the service does not have permission to be
// a virtual tv remote controller, do not trust it.
Slog.w(TAG, "Ignoring atv remote provider service because its package does not "
+ "have TV_VIRTUAL_REMOTE_CONTROLLER permission: " + serviceInfo.packageName);
return false;
}
// Looks good.
return true;
}
// Returns true only if these permissions are present in calling package.
// Manifest.permission.TV_VIRTUAL_REMOTE_CONTROLLER : virtual remote controller on TV
private boolean hasNecessaryPermissions(String packageName) {
if ((mPackageManager.checkPermission(Manifest.permission.TV_VIRTUAL_REMOTE_CONTROLLER,
packageName) == PackageManager.PERMISSION_GRANTED)) {
return true;
}
return false;
}
private int findProvider(String packageName, String className) {
int count = mProviderProxies.size();
for (int i = 0; i < count; i++) {
TvRemoteProviderProxy provider = mProviderProxies.get(i);
if (provider.hasComponentName(packageName, className)) {
return i;
}
}
return -1;
}
private final BroadcastReceiver mScanPackagesReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
if (DEBUG) {
Slog.d(TAG, "Received package manager broadcast: " + intent);
}
mHandler.post(mScanPackagesRunnable);
}
};
private final Runnable mScanPackagesRunnable = new Runnable() {
@Override
public void run() {
scanPackages();
}
};
public interface ProviderMethods {
void addProvider(TvRemoteProviderProxy providerProxy);
void removeProvider(TvRemoteProviderProxy providerProxy);
}
}