1 files changed, 219 insertions, 0 deletions
diff --git a/services/core/java/com/android/server/media/RemoteDisplayProviderWatcher.java b/services/core/java/com/android/server/media/RemoteDisplayProviderWatcher.java
new file mode 100644
index 0000000..6a5f563
--- /dev/null
+++ b/services/core/java/com/android/server/media/RemoteDisplayProviderWatcher.java
@@ -0,0 +1,219 @@
+/*
+ * Copyright (C) 2013 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.media;
+
+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.media.RemoteDisplayState;
+import android.os.Handler;
+import android.os.UserHandle;
+import android.util.Log;
+import android.util.Slog;
+
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.Collections;
+
+/**
+ * Watches for remote display provider services to be installed.
+ * Adds a provider to the media router for each registered service.
+ *
+ * @see RemoteDisplayProviderProxy
+ */
+public final class RemoteDisplayProviderWatcher {
+    private static final String TAG = "RemoteDisplayProvider";  // max. 23 chars
+    private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
+
+    private final Context mContext;
+    private final Callback mCallback;
+    private final Handler mHandler;
+    private final int mUserId;
+    private final PackageManager mPackageManager;
+
+    private final ArrayList<RemoteDisplayProviderProxy> mProviders =
+            new ArrayList<RemoteDisplayProviderProxy>();
+    private boolean mRunning;
+
+    public RemoteDisplayProviderWatcher(Context context,
+            Callback callback, Handler handler, int userId) {
+        mContext = context;
+        mCallback = callback;
+        mHandler = handler;
+        mUserId = userId;
+        mPackageManager = context.getPackageManager();
+    }
+
+    public void dump(PrintWriter pw, String prefix) {
+        pw.println(prefix + "Watcher");
+        pw.println(prefix + "  mUserId=" + mUserId);
+        pw.println(prefix + "  mRunning=" + mRunning);
+        pw.println(prefix + "  mProviders.size()=" + mProviders.size());
+    }
+
+    public void 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 = mProviders.size() - 1; i >= 0; i--) {
+                mProviders.get(i).stop();
+            }
+        }
+    }
+
+    private void scanPackages() {
+        if (!mRunning) {
+            return;
+        }
+
+        // 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(RemoteDisplayState.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) {
+                    RemoteDisplayProviderProxy provider =
+                            new RemoteDisplayProviderProxy(mContext,
+                            new ComponentName(serviceInfo.packageName, serviceInfo.name),
+                            mUserId);
+                    provider.start();
+                    mProviders.add(targetIndex++, provider);
+                    mCallback.addProvider(provider);
+                } else if (sourceIndex >= targetIndex) {
+                    RemoteDisplayProviderProxy provider = mProviders.get(sourceIndex);
+                    provider.start(); // restart the provider if needed
+                    provider.rebindIfDisconnected();
+                    Collections.swap(mProviders, sourceIndex, targetIndex++);
+                }
+            }
+        }
+
+        // Remove providers for missing services.
+        if (targetIndex < mProviders.size()) {
+            for (int i = mProviders.size() - 1; i >= targetIndex; i--) {
+                RemoteDisplayProviderProxy provider = mProviders.get(i);
+                mCallback.removeProvider(provider);
+                mProviders.remove(provider);
+                provider.stop();
+            }
+        }
+    }
+
+    private boolean verifyServiceTrusted(ServiceInfo serviceInfo) {
+        if (serviceInfo.permission == null || !serviceInfo.permission.equals(
+                Manifest.permission.BIND_REMOTE_DISPLAY)) {
+            // If the service does not require this permission then any app could
+            // potentially bind to it and cause the remote display service to
+            // misbehave.  So we only want to trust providers that require the
+            // correct permissions.
+            Slog.w(TAG, "Ignoring remote display provider service because it did not "
+                    + "require the BIND_REMOTE_DISPLAY permission in its manifest: "
+                    + serviceInfo.packageName + "/" + serviceInfo.name);
+            return false;
+        }
+        if (!hasCaptureVideoPermission(serviceInfo.packageName)) {
+            // If the service does not have permission to capture video then it
+            // isn't going to be terribly useful as a remote display, is it?
+            // Kind of makes you wonder what it's doing there in the first place.
+            Slog.w(TAG, "Ignoring remote display provider service because it does not "
+                    + "have the CAPTURE_VIDEO_OUTPUT or CAPTURE_SECURE_VIDEO_OUTPUT "
+                    + "permission: " + serviceInfo.packageName + "/" + serviceInfo.name);
+            return false;
+        }
+        // Looks good.
+        return true;
+    }
+
+    private boolean hasCaptureVideoPermission(String packageName) {
+        if (mPackageManager.checkPermission(Manifest.permission.CAPTURE_VIDEO_OUTPUT,
+                packageName) == PackageManager.PERMISSION_GRANTED) {
+            return true;
+        }
+        if (mPackageManager.checkPermission(Manifest.permission.CAPTURE_SECURE_VIDEO_OUTPUT,
+                packageName) == PackageManager.PERMISSION_GRANTED) {
+            return true;
+        }
+        return false;
+    }
+
+    private int findProvider(String packageName, String className) {
+        int count = mProviders.size();
+        for (int i = 0; i < count; i++) {
+            RemoteDisplayProviderProxy provider = mProviders.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);
+            }
+            scanPackages();
+        }
+    };
+
+    private final Runnable mScanPackagesRunnable = new Runnable() {
+        @Override
+        public void run() {
+            scanPackages();
+        }
+    };
+
+    public interface Callback {
+        void addProvider(RemoteDisplayProviderProxy provider);
+        void removeProvider(RemoteDisplayProviderProxy provider);
+    }
+}