android-35/android/telephony/mbms/MbmsDownloadReceiver.java - platform/prebuilts/fullsdk/sources - Git at Google

 /*
  * Copyright (C) 2017 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 android.telephony.mbms;

 import android.annotation.SystemApi;
 import android.content.BroadcastReceiver;
 import android.content.ContentResolver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.pm.ActivityInfo;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
 import android.net.Uri;
 import android.os.Bundle;
 import android.telephony.MbmsDownloadSession;
 import android.telephony.mbms.vendor.VendorUtils;
 import android.util.Log;

 import com.android.internal.annotations.VisibleForTesting;

 import java.io.File;
 import java.io.FileFilter;
 import java.io.IOException;
 import java.nio.file.FileSystems;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 import java.util.UUID;

 /**
  * The {@link BroadcastReceiver} responsible for handling intents sent from the middleware. Apps
  * that wish to download using MBMS APIs should declare this class in their AndroidManifest.xml as
  * follows:
 <pre>{@code
 <receiver
     android:name="android.telephony.mbms.MbmsDownloadReceiver"
     android:permission="android.permission.SEND_EMBMS_INTENTS"
     android:enabled="true"
     android:exported="true">
 </receiver>}</pre>
  */
 public class MbmsDownloadReceiver extends BroadcastReceiver {
     /** @hide */
     public static final String DOWNLOAD_TOKEN_SUFFIX = ".download_token";
     /** @hide */
     public static final String MBMS_FILE_PROVIDER_META_DATA_KEY = "mbms-file-provider-authority";

     private static final String EMBMS_INTENT_PERMISSION = "android.permission.SEND_EMBMS_INTENTS";

     /**
      * Indicates that the requested operation completed without error.
      * @hide
      */
     @SystemApi
     public static final int RESULT_OK = 0;

     /**
      * Indicates that the intent sent had an invalid action. This will be the result if
      * {@link Intent#getAction()} returns anything other than
      * {@link VendorUtils#ACTION_DOWNLOAD_RESULT_INTERNAL},
      * {@link VendorUtils#ACTION_FILE_DESCRIPTOR_REQUEST}, or
      * {@link VendorUtils#ACTION_CLEANUP}.
      * This is a fatal result code and no result extras should be expected.
      * @hide
      */
     @SystemApi
     public static final int RESULT_INVALID_ACTION = 1;

     /**
      * Indicates that the intent was missing some required extras.
      * This is a fatal result code and no result extras should be expected.
      * @hide
      */
     @SystemApi
     public static final int RESULT_MALFORMED_INTENT = 2;

     /**
      * Indicates that the supplied value for {@link VendorUtils#EXTRA_TEMP_FILE_ROOT}
      * does not match what the app has stored.
      * This is a fatal result code and no result extras should be expected.
      * @hide
      */
     @SystemApi
     public static final int RESULT_BAD_TEMP_FILE_ROOT = 3;

     /**
      * Indicates that the manager was unable to move the completed download to its final location.
      * This is a fatal result code and no result extras should be expected.
      * @hide
      */
     @SystemApi
     public static final int RESULT_DOWNLOAD_FINALIZATION_ERROR = 4;

     /**
      * Indicates that the manager was unable to generate one or more of the requested file
      * descriptors.
      * This is a non-fatal result code -- some file descriptors may still be generated, but there
      * is no guarantee that they will be the same number as requested.
      * @hide
      */
     @SystemApi
     public static final int RESULT_TEMP_FILE_GENERATION_ERROR = 5;

     /**
      * Indicates that the manager was unable to notify the app of the completed download.
      * This is a fatal result code and no result extras should be expected.
      * @hide
      */
     @SystemApi
     public static final int RESULT_APP_NOTIFICATION_ERROR = 6;


     private static final String LOG_TAG = "MbmsDownloadReceiver";
     private static final String TEMP_FILE_SUFFIX = ".embms.temp";
     private static final String TEMP_FILE_STAGING_LOCATION = "staged_completed_files";

     private static final int MAX_TEMP_FILE_RETRIES = 5;

     private String mFileProviderAuthorityCache = null;
     private String mMiddlewarePackageNameCache = null;

     /** @hide */
     @Override
     public void onReceive(Context context, Intent intent) {
         verifyPermissionIntegrity(context);

         if (!verifyIntentContents(context, intent)) {
             setResultCode(RESULT_MALFORMED_INTENT);
             return;
         }
         if (!Objects.equals(intent.getStringExtra(VendorUtils.EXTRA_TEMP_FILE_ROOT),
                 MbmsTempFileProvider.getEmbmsTempFileDir(context).getPath())) {
             setResultCode(RESULT_BAD_TEMP_FILE_ROOT);
             return;
         }

         if (VendorUtils.ACTION_DOWNLOAD_RESULT_INTERNAL.equals(intent.getAction())) {
             moveDownloadedFile(context, intent);
             cleanupPostMove(context, intent);
         } else if (VendorUtils.ACTION_FILE_DESCRIPTOR_REQUEST.equals(intent.getAction())) {
             generateTempFiles(context, intent);
         } else if (VendorUtils.ACTION_CLEANUP.equals(intent.getAction())) {
             cleanupTempFiles(context, intent);
         } else {
             setResultCode(RESULT_INVALID_ACTION);
         }
     }

     private boolean verifyIntentContents(Context context, Intent intent) {
         if (VendorUtils.ACTION_DOWNLOAD_RESULT_INTERNAL.equals(intent.getAction())) {
             if (!intent.hasExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_RESULT)) {
                 Log.w(LOG_TAG, "Download result did not include a result code. Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_REQUEST)) {
                 Log.w(LOG_TAG, "Download result did not include the associated request. Ignoring.");
                 return false;
             }
             // We do not need to verify below extras if the result is not success.
             if (MbmsDownloadSession.RESULT_SUCCESSFUL !=
                     intent.getIntExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_RESULT,
                     MbmsDownloadSession.RESULT_CANCELLED)) {
                 return true;
             }
             if (!intent.hasExtra(VendorUtils.EXTRA_TEMP_FILE_ROOT)) {
                 Log.w(LOG_TAG, "Download result did not include the temp file root. Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(MbmsDownloadSession.EXTRA_MBMS_FILE_INFO)) {
                 Log.w(LOG_TAG, "Download result did not include the associated file info. " +
                         "Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(VendorUtils.EXTRA_FINAL_URI)) {
                 Log.w(LOG_TAG, "Download result did not include the path to the final " +
                         "temp file. Ignoring.");
                 return false;
             }
             DownloadRequest request = intent.getParcelableExtra(
                     MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_REQUEST, android.telephony.mbms.DownloadRequest.class);
             String expectedTokenFileName = request.getHash() + DOWNLOAD_TOKEN_SUFFIX;
             File expectedTokenFile = new File(
                     MbmsUtils.getEmbmsTempFileDirForService(context, request.getFileServiceId()),
                     expectedTokenFileName);
             if (!expectedTokenFile.exists()) {
                 Log.w(LOG_TAG, "Supplied download request does not match a token that we have. " +
                         "Expected " + expectedTokenFile);
                 return false;
             }
         } else if (VendorUtils.ACTION_FILE_DESCRIPTOR_REQUEST.equals(intent.getAction())) {
             if (!intent.hasExtra(VendorUtils.EXTRA_SERVICE_ID)) {
                 Log.w(LOG_TAG, "Temp file request did not include the associated service id." +
                         " Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(VendorUtils.EXTRA_TEMP_FILE_ROOT)) {
                 Log.w(LOG_TAG, "Download result did not include the temp file root. Ignoring.");
                 return false;
             }
         } else if (VendorUtils.ACTION_CLEANUP.equals(intent.getAction())) {
             if (!intent.hasExtra(VendorUtils.EXTRA_SERVICE_ID)) {
                 Log.w(LOG_TAG, "Cleanup request did not include the associated service id." +
                         " Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(VendorUtils.EXTRA_TEMP_FILE_ROOT)) {
                 Log.w(LOG_TAG, "Cleanup request did not include the temp file root. Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(VendorUtils.EXTRA_TEMP_FILES_IN_USE)) {
                 Log.w(LOG_TAG, "Cleanup request did not include the list of temp files in use. " +
                         "Ignoring.");
                 return false;
             }
         }
         return true;
     }

     private void moveDownloadedFile(Context context, Intent intent) {
         DownloadRequest request = intent.getParcelableExtra(
                 MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_REQUEST, android.telephony.mbms.DownloadRequest.class);
         Intent intentForApp = request.getIntentForApp();
         if (intentForApp == null) {
             Log.i(LOG_TAG, "Malformed app notification intent");
             setResultCode(RESULT_APP_NOTIFICATION_ERROR);
             return;
         }

         int result = intent.getIntExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_RESULT,
                 MbmsDownloadSession.RESULT_CANCELLED);
         intentForApp.putExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_RESULT, result);
         intentForApp.putExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_REQUEST, request);

         if (result != MbmsDownloadSession.RESULT_SUCCESSFUL) {
             Log.i(LOG_TAG, "Download request indicated a failed download. Aborting.");
             context.sendBroadcast(intentForApp);
             setResultCode(RESULT_OK);
             return;
         }

         Uri finalTempFile = intent.getParcelableExtra(VendorUtils.EXTRA_FINAL_URI, android.net.Uri.class);
         if (!verifyTempFilePath(context, request.getFileServiceId(), finalTempFile)) {
             Log.w(LOG_TAG, "Download result specified an invalid temp file " + finalTempFile);
             setResultCode(RESULT_DOWNLOAD_FINALIZATION_ERROR);
             return;
         }

         FileInfo completedFileInfo =
                 (FileInfo) intent.getParcelableExtra(MbmsDownloadSession.EXTRA_MBMS_FILE_INFO, android.telephony.mbms.FileInfo.class);
         Path appSpecifiedDestination = FileSystems.getDefault().getPath(
                 request.getDestinationUri().getPath());

         Uri finalLocation;
         try {
             String relativeLocation = getFileRelativePath(request.getSourceUri().getPath(),
                     completedFileInfo.getUri().getPath());
             finalLocation = moveToFinalLocation(finalTempFile, appSpecifiedDestination,
                     relativeLocation);
         } catch (IOException e) {
             Log.w(LOG_TAG, "Failed to move temp file to final destination");
             setResultCode(RESULT_DOWNLOAD_FINALIZATION_ERROR);
             return;
         }
         intentForApp.putExtra(MbmsDownloadSession.EXTRA_MBMS_COMPLETED_FILE_URI, finalLocation);
         intentForApp.putExtra(MbmsDownloadSession.EXTRA_MBMS_FILE_INFO, completedFileInfo);

         context.sendBroadcast(intentForApp);
         setResultCode(RESULT_OK);
     }

     private void cleanupPostMove(Context context, Intent intent) {
         DownloadRequest request = intent.getParcelableExtra(
                 MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_REQUEST, android.telephony.mbms.DownloadRequest.class);
         if (request == null) {
             Log.w(LOG_TAG, "Intent does not include a DownloadRequest. Ignoring.");
             return;
         }

         List<Uri> tempFiles = intent.getParcelableArrayListExtra(VendorUtils.EXTRA_TEMP_LIST, android.net.Uri.class);
         if (tempFiles == null) {
             return;
         }

         for (Uri tempFileUri : tempFiles) {
             if (verifyTempFilePath(context, request.getFileServiceId(), tempFileUri)) {
                 File tempFile = new File(tempFileUri.getSchemeSpecificPart());
                 if (!tempFile.delete()) {
                     Log.w(LOG_TAG, "Failed to delete temp file at " + tempFile.getPath());
                 }
             }
         }
     }

     private void generateTempFiles(Context context, Intent intent) {
         String serviceId = intent.getStringExtra(VendorUtils.EXTRA_SERVICE_ID);
         if (serviceId == null) {
             Log.w(LOG_TAG, "Temp file request did not include the associated service id. " +
                     "Ignoring.");
             setResultCode(RESULT_MALFORMED_INTENT);
             return;
         }
         int fdCount = intent.getIntExtra(VendorUtils.EXTRA_FD_COUNT, 0);
         List<Uri> pausedList = intent.getParcelableArrayListExtra(VendorUtils.EXTRA_PAUSED_LIST, android.net.Uri.class);

         if (fdCount == 0 && (pausedList == null || pausedList.size() == 0)) {
             Log.i(LOG_TAG, "No temp files actually requested. Ending.");
             setResultCode(RESULT_OK);
             setResultExtras(Bundle.EMPTY);
             return;
         }

         ArrayList<UriPathPair> freshTempFiles =
                 generateFreshTempFiles(context, serviceId, fdCount);
         ArrayList<UriPathPair> pausedFiles =
                 generateUrisForPausedFiles(context, serviceId, pausedList);

         Bundle result = new Bundle();
         result.putParcelableArrayList(VendorUtils.EXTRA_FREE_URI_LIST, freshTempFiles);
         result.putParcelableArrayList(VendorUtils.EXTRA_PAUSED_URI_LIST, pausedFiles);
         setResultCode(RESULT_OK);
         setResultExtras(result);
     }

     private ArrayList<UriPathPair> generateFreshTempFiles(Context context, String serviceId,
             int freshFdCount) {
         File tempFileDir = MbmsUtils.getEmbmsTempFileDirForService(context, serviceId);
         if (!tempFileDir.exists()) {
             tempFileDir.mkdirs();
         }

         // Name the files with the template "N-UUID", where N is the request ID and UUID is a
         // random uuid.
         ArrayList<UriPathPair> result = new ArrayList<>(freshFdCount);
         for (int i = 0; i < freshFdCount; i++) {
             File tempFile = generateSingleTempFile(tempFileDir);
             if (tempFile == null) {
                 setResultCode(RESULT_TEMP_FILE_GENERATION_ERROR);
                 Log.w(LOG_TAG, "Failed to generate a temp file. Moving on.");
                 continue;
             }
             Uri fileUri = Uri.fromFile(tempFile);
             Uri contentUri = MbmsTempFileProvider.getUriForFile(
                     context, getFileProviderAuthorityCached(context), tempFile);
             context.grantUriPermission(getMiddlewarePackageCached(context), contentUri,
                     Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
             result.add(new UriPathPair(fileUri, contentUri));
         }

         return result;
     }

     private static File generateSingleTempFile(File tempFileDir) {
         int numTries = 0;
         while (numTries < MAX_TEMP_FILE_RETRIES) {
             numTries++;
             String fileName =  UUID.randomUUID() + TEMP_FILE_SUFFIX;
             File tempFile = new File(tempFileDir, fileName);
             try {
                 if (tempFile.createNewFile()) {
                     return tempFile.getCanonicalFile();
                 }
             } catch (IOException e) {
                 continue;
             }
         }
         return null;
     }

     private ArrayList<UriPathPair> generateUrisForPausedFiles(Context context,
             String serviceId, List<Uri> pausedFiles) {
         if (pausedFiles == null) {
             return new ArrayList<>(0);
         }
         ArrayList<UriPathPair> result = new ArrayList<>(pausedFiles.size());

         for (Uri fileUri : pausedFiles) {
             if (!verifyTempFilePath(context, serviceId, fileUri)) {
                 Log.w(LOG_TAG, "Supplied file " + fileUri + " is not a valid temp file to resume");
                 setResultCode(RESULT_TEMP_FILE_GENERATION_ERROR);
                 continue;
             }
             File tempFile = new File(fileUri.getSchemeSpecificPart());
             if (!tempFile.exists()) {
                 Log.w(LOG_TAG, "Supplied file " + fileUri + " does not exist.");
                 setResultCode(RESULT_TEMP_FILE_GENERATION_ERROR);
                 continue;
             }
             Uri contentUri = MbmsTempFileProvider.getUriForFile(
                     context, getFileProviderAuthorityCached(context), tempFile);
             context.grantUriPermission(getMiddlewarePackageCached(context), contentUri,
                     Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);

             result.add(new UriPathPair(fileUri, contentUri));
         }
         return result;
     }

     private void cleanupTempFiles(Context context, Intent intent) {
         String serviceId = intent.getStringExtra(VendorUtils.EXTRA_SERVICE_ID);
         File tempFileDir = MbmsUtils.getEmbmsTempFileDirForService(context, serviceId);
         final List<Uri> filesInUse =
                 intent.getParcelableArrayListExtra(VendorUtils.EXTRA_TEMP_FILES_IN_USE, android.net.Uri.class);
         File[] filesToDelete = tempFileDir.listFiles(new FileFilter() {
             @Override
             public boolean accept(File file) {
                 File canonicalFile;
                 try {
                     canonicalFile = file.getCanonicalFile();
                 } catch (IOException e) {
                     Log.w(LOG_TAG, "Got IOException canonicalizing " + file + ", not deleting.");
                     return false;
                 }
                 // Reject all files that don't match what we think a temp file should look like
                 // e.g. download tokens
                 if (!canonicalFile.getName().endsWith(TEMP_FILE_SUFFIX)) {
                     return false;
                 }
                 // If any of the files in use match the uri, return false to reject it from the
                 // list to delete.
                 Uri fileInUseUri = Uri.fromFile(canonicalFile);
                 return !filesInUse.contains(fileInUseUri);
             }
         });
         for (File fileToDelete : filesToDelete) {
             fileToDelete.delete();
         }
     }

     /*
      * Moves a tempfile located at fromPath to its final home where the app wants it
      */
     private static Uri moveToFinalLocation(Uri fromPath, Path appSpecifiedPath,
             String relativeLocation) throws IOException {
         if (!ContentResolver.SCHEME_FILE.equals(fromPath.getScheme())) {
             Log.w(LOG_TAG, "Downloaded file location uri " + fromPath +
                     " does not have a file scheme");
             return null;
         }

         Path fromFile = FileSystems.getDefault().getPath(fromPath.getPath());
         Path toFile = appSpecifiedPath.resolve(relativeLocation);

         if (!Files.isDirectory(toFile.getParent())) {
             Files.createDirectories(toFile.getParent());
         }
         Path result = Files.move(fromFile, toFile,
                 StandardCopyOption.REPLACE_EXISTING, StandardCopyOption.ATOMIC_MOVE);

         return Uri.fromFile(result.toFile());
     }

     /**
      * @hide
      */
     @VisibleForTesting
     public static String getFileRelativePath(String sourceUriPath, String fileInfoPath) {
         if (sourceUriPath.endsWith("*")) {
             // This is a wildcard path. Strip the last path component and use that as the root of
             // the relative path.
             int lastSlash = sourceUriPath.lastIndexOf('/');
             sourceUriPath = sourceUriPath.substring(0, lastSlash);
         }
         if (!fileInfoPath.startsWith(sourceUriPath)) {
             Log.e(LOG_TAG, "File location specified in FileInfo does not match the source URI."
                     + " source: " + sourceUriPath + " fileinfo path: " + fileInfoPath);
             return null;
         }
         if (fileInfoPath.length() == sourceUriPath.length()) {
             // This is the single-file download case. Return the name of the file so that the
             // receiver puts the file directly into the dest directory.
             return sourceUriPath.substring(sourceUriPath.lastIndexOf('/') + 1);
         }

         String prefixOmittedPath = fileInfoPath.substring(sourceUriPath.length());
         if (prefixOmittedPath.startsWith("/")) {
             prefixOmittedPath = prefixOmittedPath.substring(1);
         }
         return prefixOmittedPath;
     }

     private static boolean verifyTempFilePath(Context context, String serviceId,
             Uri filePath) {
         if (!ContentResolver.SCHEME_FILE.equals(filePath.getScheme())) {
             Log.w(LOG_TAG, "Uri " + filePath + " does not have a file scheme");
             return false;
         }

         String path = filePath.getSchemeSpecificPart();
         File tempFile = new File(path);
         if (!tempFile.exists()) {
             Log.w(LOG_TAG, "File at " + path + " does not exist.");
             return false;
         }

         if (!MbmsUtils.isContainedIn(
                 MbmsUtils.getEmbmsTempFileDirForService(context, serviceId), tempFile)) {
             Log.w(LOG_TAG, "File at " + path + " is not contained in the temp file root," +
                     " which is " + MbmsUtils.getEmbmsTempFileDirForService(context, serviceId));
             return false;
         }

         return true;
     }

     private String getFileProviderAuthorityCached(Context context) {
         if (mFileProviderAuthorityCache != null) {
             return mFileProviderAuthorityCache;
         }

         mFileProviderAuthorityCache = getFileProviderAuthority(context);
         return mFileProviderAuthorityCache;
     }

     private static String getFileProviderAuthority(Context context) {
         ApplicationInfo appInfo;
         try {
             appInfo = context.getPackageManager()
                     .getApplicationInfo(context.getPackageName(), PackageManager.GET_META_DATA);
         } catch (PackageManager.NameNotFoundException e) {
             throw new RuntimeException("Package manager couldn't find " + context.getPackageName());
         }
         if (appInfo.metaData == null) {
             throw new RuntimeException("App must declare the file provider authority as metadata " +
                     "in the manifest.");
         }
         String authority = appInfo.metaData.getString(MBMS_FILE_PROVIDER_META_DATA_KEY);
         if (authority == null) {
             throw new RuntimeException("App must declare the file provider authority as metadata " +
                     "in the manifest.");
         }
         return authority;
     }

     private String getMiddlewarePackageCached(Context context) {
         if (mMiddlewarePackageNameCache == null) {
             mMiddlewarePackageNameCache = MbmsUtils.getMiddlewareServiceInfo(context,
                     MbmsDownloadSession.MBMS_DOWNLOAD_SERVICE_ACTION).packageName;
         }
         return mMiddlewarePackageNameCache;
     }

     private void verifyPermissionIntegrity(Context context) {
         PackageManager pm = context.getPackageManager();
         Intent queryIntent = new Intent(context, MbmsDownloadReceiver.class);
         List<ResolveInfo> infos = pm.queryBroadcastReceivers(queryIntent, 0);
         if (infos.size() != 1) {
             throw new IllegalStateException("Non-unique download receiver in your app");
         }
         ActivityInfo selfInfo = infos.get(0).activityInfo;
         if (selfInfo == null) {
             throw new IllegalStateException("Queried ResolveInfo does not contain a receiver");
         }
         if (MbmsUtils.getOverrideServiceName(context,
                 MbmsDownloadSession.MBMS_DOWNLOAD_SERVICE_ACTION) != null) {
             // If an override was specified, just make sure that the permission isn't null.
             if (selfInfo.permission == null) {
                 throw new IllegalStateException(
                         "MbmsDownloadReceiver must require some permission");
             }
             return;
         }
         if (!Objects.equals(EMBMS_INTENT_PERMISSION, selfInfo.permission)) {
             throw new IllegalStateException("MbmsDownloadReceiver must require the " +
                     "SEND_EMBMS_INTENTS permission.");
         }
     }
 }
	/*
	* Copyright (C) 2017 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 android.telephony.mbms;

	import android.annotation.SystemApi;
	import android.content.BroadcastReceiver;
	import android.content.ContentResolver;
	import android.content.Context;
	import android.content.Intent;
	import android.content.pm.ActivityInfo;
	import android.content.pm.ApplicationInfo;
	import android.content.pm.PackageManager;
	import android.content.pm.ResolveInfo;
	import android.net.Uri;
	import android.os.Bundle;
	import android.telephony.MbmsDownloadSession;
	import android.telephony.mbms.vendor.VendorUtils;
	import android.util.Log;

	import com.android.internal.annotations.VisibleForTesting;

	import java.io.File;
	import java.io.FileFilter;
	import java.io.IOException;
	import java.nio.file.FileSystems;
	import java.nio.file.Files;
	import java.nio.file.Path;
	import java.nio.file.StandardCopyOption;
	import java.util.ArrayList;
	import java.util.List;
	import java.util.Objects;
	import java.util.UUID;

	/**
	* The {@link BroadcastReceiver} responsible for handling intents sent from the middleware. Apps
	* that wish to download using MBMS APIs should declare this class in their AndroidManifest.xml as
	* follows:
	<pre>{@code
	<receiver
	android:name="android.telephony.mbms.MbmsDownloadReceiver"
	android:permission="android.permission.SEND_EMBMS_INTENTS"
	android:enabled="true"
	android:exported="true">
	</receiver>}</pre>
	*/
	public class MbmsDownloadReceiver extends BroadcastReceiver {
	/** @hide */
	public static final String DOWNLOAD_TOKEN_SUFFIX = ".download_token";
	/** @hide */
	public static final String MBMS_FILE_PROVIDER_META_DATA_KEY = "mbms-file-provider-authority";

	private static final String EMBMS_INTENT_PERMISSION = "android.permission.SEND_EMBMS_INTENTS";

	/**
	* Indicates that the requested operation completed without error.
	* @hide
	*/
	@SystemApi
	public static final int RESULT_OK = 0;

	/**
	* Indicates that the intent sent had an invalid action. This will be the result if
	* {@link Intent#getAction()} returns anything other than
	* {@link VendorUtils#ACTION_DOWNLOAD_RESULT_INTERNAL},
	* {@link VendorUtils#ACTION_FILE_DESCRIPTOR_REQUEST}, or
	* {@link VendorUtils#ACTION_CLEANUP}.
	* This is a fatal result code and no result extras should be expected.
	* @hide
	*/
	@SystemApi
	public static final int RESULT_INVALID_ACTION = 1;

	/**
	* Indicates that the intent was missing some required extras.
	* This is a fatal result code and no result extras should be expected.
	* @hide
	*/
	@SystemApi
	public static final int RESULT_MALFORMED_INTENT = 2;

	/**
	* Indicates that the supplied value for {@link VendorUtils#EXTRA_TEMP_FILE_ROOT}
	* does not match what the app has stored.
	* This is a fatal result code and no result extras should be expected.
	* @hide
	*/
	@SystemApi
	public static final int RESULT_BAD_TEMP_FILE_ROOT = 3;

	/**
	* Indicates that the manager was unable to move the completed download to its final location.
	* This is a fatal result code and no result extras should be expected.
	* @hide
	*/
	@SystemApi
	public static final int RESULT_DOWNLOAD_FINALIZATION_ERROR = 4;

	/**
	* Indicates that the manager was unable to generate one or more of the requested file
	* descriptors.
	* This is a non-fatal result code -- some file descriptors may still be generated, but there
	* is no guarantee that they will be the same number as requested.
	* @hide
	*/
	@SystemApi
	public static final int RESULT_TEMP_FILE_GENERATION_ERROR = 5;

	/**
	* Indicates that the manager was unable to notify the app of the completed download.
	* This is a fatal result code and no result extras should be expected.
	* @hide
	*/
	@SystemApi
	public static final int RESULT_APP_NOTIFICATION_ERROR = 6;


	private static final String LOG_TAG = "MbmsDownloadReceiver";
	private static final String TEMP_FILE_SUFFIX = ".embms.temp";
	private static final String TEMP_FILE_STAGING_LOCATION = "staged_completed_files";

	private static final int MAX_TEMP_FILE_RETRIES = 5;

	private String mFileProviderAuthorityCache = null;
	private String mMiddlewarePackageNameCache = null;

	/** @hide */
	@Override
	public void onReceive(Context context, Intent intent) {
	verifyPermissionIntegrity(context);

	if (!verifyIntentContents(context, intent)) {
	setResultCode(RESULT_MALFORMED_INTENT);
	return;
	}
	if (!Objects.equals(intent.getStringExtra(VendorUtils.EXTRA_TEMP_FILE_ROOT),
	MbmsTempFileProvider.getEmbmsTempFileDir(context).getPath())) {
	setResultCode(RESULT_BAD_TEMP_FILE_ROOT);
	return;
	}

	if (VendorUtils.ACTION_DOWNLOAD_RESULT_INTERNAL.equals(intent.getAction())) {
	moveDownloadedFile(context, intent);
	cleanupPostMove(context, intent);
	} else if (VendorUtils.ACTION_FILE_DESCRIPTOR_REQUEST.equals(intent.getAction())) {
	generateTempFiles(context, intent);
	} else if (VendorUtils.ACTION_CLEANUP.equals(intent.getAction())) {
	cleanupTempFiles(context, intent);
	} else {
	setResultCode(RESULT_INVALID_ACTION);
	}
	}

	private boolean verifyIntentContents(Context context, Intent intent) {
	if (VendorUtils.ACTION_DOWNLOAD_RESULT_INTERNAL.equals(intent.getAction())) {
	if (!intent.hasExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_RESULT)) {
	Log.w(LOG_TAG, "Download result did not include a result code. Ignoring.");
	return false;
	}
	if (!intent.hasExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_REQUEST)) {
	Log.w(LOG_TAG, "Download result did not include the associated request. Ignoring.");
	return false;
	}
	// We do not need to verify below extras if the result is not success.
	if (MbmsDownloadSession.RESULT_SUCCESSFUL !=
	intent.getIntExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_RESULT,
	MbmsDownloadSession.RESULT_CANCELLED)) {
	return true;
	}
	if (!intent.hasExtra(VendorUtils.EXTRA_TEMP_FILE_ROOT)) {
	Log.w(LOG_TAG, "Download result did not include the temp file root. Ignoring.");
	return false;
	}
	if (!intent.hasExtra(MbmsDownloadSession.EXTRA_MBMS_FILE_INFO)) {
	Log.w(LOG_TAG, "Download result did not include the associated file info. " +
	"Ignoring.");
	return false;
	}
	if (!intent.hasExtra(VendorUtils.EXTRA_FINAL_URI)) {
	Log.w(LOG_TAG, "Download result did not include the path to the final " +
	"temp file. Ignoring.");
	return false;
	}
	DownloadRequest request = intent.getParcelableExtra(
	MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_REQUEST, android.telephony.mbms.DownloadRequest.class);
	String expectedTokenFileName = request.getHash() + DOWNLOAD_TOKEN_SUFFIX;
	File expectedTokenFile = new File(
	MbmsUtils.getEmbmsTempFileDirForService(context, request.getFileServiceId()),
	expectedTokenFileName);
	if (!expectedTokenFile.exists()) {
	Log.w(LOG_TAG, "Supplied download request does not match a token that we have. " +
	"Expected " + expectedTokenFile);
	return false;
	}
	} else if (VendorUtils.ACTION_FILE_DESCRIPTOR_REQUEST.equals(intent.getAction())) {
	if (!intent.hasExtra(VendorUtils.EXTRA_SERVICE_ID)) {
	Log.w(LOG_TAG, "Temp file request did not include the associated service id." +
	" Ignoring.");
	return false;
	}
	if (!intent.hasExtra(VendorUtils.EXTRA_TEMP_FILE_ROOT)) {
	Log.w(LOG_TAG, "Download result did not include the temp file root. Ignoring.");
	return false;
	}
	} else if (VendorUtils.ACTION_CLEANUP.equals(intent.getAction())) {
	if (!intent.hasExtra(VendorUtils.EXTRA_SERVICE_ID)) {
	Log.w(LOG_TAG, "Cleanup request did not include the associated service id." +
	" Ignoring.");
	return false;
	}
	if (!intent.hasExtra(VendorUtils.EXTRA_TEMP_FILE_ROOT)) {
	Log.w(LOG_TAG, "Cleanup request did not include the temp file root. Ignoring.");
	return false;
	}
	if (!intent.hasExtra(VendorUtils.EXTRA_TEMP_FILES_IN_USE)) {
	Log.w(LOG_TAG, "Cleanup request did not include the list of temp files in use. " +
	"Ignoring.");
	return false;
	}
	}
	return true;
	}

	private void moveDownloadedFile(Context context, Intent intent) {
	DownloadRequest request = intent.getParcelableExtra(
	MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_REQUEST, android.telephony.mbms.DownloadRequest.class);
	Intent intentForApp = request.getIntentForApp();
	if (intentForApp == null) {
	Log.i(LOG_TAG, "Malformed app notification intent");
	setResultCode(RESULT_APP_NOTIFICATION_ERROR);
	return;
	}

	int result = intent.getIntExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_RESULT,
	MbmsDownloadSession.RESULT_CANCELLED);
	intentForApp.putExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_RESULT, result);
	intentForApp.putExtra(MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_REQUEST, request);

	if (result != MbmsDownloadSession.RESULT_SUCCESSFUL) {
	Log.i(LOG_TAG, "Download request indicated a failed download. Aborting.");
	context.sendBroadcast(intentForApp);
	setResultCode(RESULT_OK);
	return;
	}

	Uri finalTempFile = intent.getParcelableExtra(VendorUtils.EXTRA_FINAL_URI, android.net.Uri.class);
	if (!verifyTempFilePath(context, request.getFileServiceId(), finalTempFile)) {
	Log.w(LOG_TAG, "Download result specified an invalid temp file " + finalTempFile);
	setResultCode(RESULT_DOWNLOAD_FINALIZATION_ERROR);
	return;
	}

	FileInfo completedFileInfo =
	(FileInfo) intent.getParcelableExtra(MbmsDownloadSession.EXTRA_MBMS_FILE_INFO, android.telephony.mbms.FileInfo.class);
	Path appSpecifiedDestination = FileSystems.getDefault().getPath(
	request.getDestinationUri().getPath());

	Uri finalLocation;
	try {
	String relativeLocation = getFileRelativePath(request.getSourceUri().getPath(),
	completedFileInfo.getUri().getPath());
	finalLocation = moveToFinalLocation(finalTempFile, appSpecifiedDestination,
	relativeLocation);
	} catch (IOException e) {
	Log.w(LOG_TAG, "Failed to move temp file to final destination");
	setResultCode(RESULT_DOWNLOAD_FINALIZATION_ERROR);
	return;
	}
	intentForApp.putExtra(MbmsDownloadSession.EXTRA_MBMS_COMPLETED_FILE_URI, finalLocation);
	intentForApp.putExtra(MbmsDownloadSession.EXTRA_MBMS_FILE_INFO, completedFileInfo);

	context.sendBroadcast(intentForApp);
	setResultCode(RESULT_OK);
	}

	private void cleanupPostMove(Context context, Intent intent) {
	DownloadRequest request = intent.getParcelableExtra(
	MbmsDownloadSession.EXTRA_MBMS_DOWNLOAD_REQUEST, android.telephony.mbms.DownloadRequest.class);
	if (request == null) {
	Log.w(LOG_TAG, "Intent does not include a DownloadRequest. Ignoring.");
	return;
	}

	List<Uri> tempFiles = intent.getParcelableArrayListExtra(VendorUtils.EXTRA_TEMP_LIST, android.net.Uri.class);
	if (tempFiles == null) {
	return;
	}

	for (Uri tempFileUri : tempFiles) {
	if (verifyTempFilePath(context, request.getFileServiceId(), tempFileUri)) {
	File tempFile = new File(tempFileUri.getSchemeSpecificPart());
	if (!tempFile.delete()) {
	Log.w(LOG_TAG, "Failed to delete temp file at " + tempFile.getPath());
	}
	}
	}
	}

	private void generateTempFiles(Context context, Intent intent) {
	String serviceId = intent.getStringExtra(VendorUtils.EXTRA_SERVICE_ID);
	if (serviceId == null) {
	Log.w(LOG_TAG, "Temp file request did not include the associated service id. " +
	"Ignoring.");
	setResultCode(RESULT_MALFORMED_INTENT);
	return;
	}
	int fdCount = intent.getIntExtra(VendorUtils.EXTRA_FD_COUNT, 0);
	List<Uri> pausedList = intent.getParcelableArrayListExtra(VendorUtils.EXTRA_PAUSED_LIST, android.net.Uri.class);

	if (fdCount == 0 && (pausedList == null \|\| pausedList.size() == 0)) {
	Log.i(LOG_TAG, "No temp files actually requested. Ending.");
	setResultCode(RESULT_OK);
	setResultExtras(Bundle.EMPTY);
	return;
	}

	ArrayList<UriPathPair> freshTempFiles =
	generateFreshTempFiles(context, serviceId, fdCount);
	ArrayList<UriPathPair> pausedFiles =
	generateUrisForPausedFiles(context, serviceId, pausedList);

	Bundle result = new Bundle();
	result.putParcelableArrayList(VendorUtils.EXTRA_FREE_URI_LIST, freshTempFiles);
	result.putParcelableArrayList(VendorUtils.EXTRA_PAUSED_URI_LIST, pausedFiles);
	setResultCode(RESULT_OK);
	setResultExtras(result);
	}

	private ArrayList<UriPathPair> generateFreshTempFiles(Context context, String serviceId,
	int freshFdCount) {
	File tempFileDir = MbmsUtils.getEmbmsTempFileDirForService(context, serviceId);
	if (!tempFileDir.exists()) {
	tempFileDir.mkdirs();
	}

	// Name the files with the template "N-UUID", where N is the request ID and UUID is a
	// random uuid.
	ArrayList<UriPathPair> result = new ArrayList<>(freshFdCount);
	for (int i = 0; i < freshFdCount; i++) {
	File tempFile = generateSingleTempFile(tempFileDir);
	if (tempFile == null) {
	setResultCode(RESULT_TEMP_FILE_GENERATION_ERROR);
	Log.w(LOG_TAG, "Failed to generate a temp file. Moving on.");
	continue;
	}
	Uri fileUri = Uri.fromFile(tempFile);
	Uri contentUri = MbmsTempFileProvider.getUriForFile(
	context, getFileProviderAuthorityCached(context), tempFile);
	context.grantUriPermission(getMiddlewarePackageCached(context), contentUri,
	Intent.FLAG_GRANT_READ_URI_PERMISSION \| Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
	result.add(new UriPathPair(fileUri, contentUri));
	}

	return result;
	}

	private static File generateSingleTempFile(File tempFileDir) {
	int numTries = 0;
	while (numTries < MAX_TEMP_FILE_RETRIES) {
	numTries++;
	String fileName = UUID.randomUUID() + TEMP_FILE_SUFFIX;
	File tempFile = new File(tempFileDir, fileName);
	try {
	if (tempFile.createNewFile()) {
	return tempFile.getCanonicalFile();
	}
	} catch (IOException e) {
	continue;
	}
	}
	return null;
	}

	private ArrayList<UriPathPair> generateUrisForPausedFiles(Context context,
	String serviceId, List<Uri> pausedFiles) {
	if (pausedFiles == null) {
	return new ArrayList<>(0);
	}
	ArrayList<UriPathPair> result = new ArrayList<>(pausedFiles.size());

	for (Uri fileUri : pausedFiles) {
	if (!verifyTempFilePath(context, serviceId, fileUri)) {
	Log.w(LOG_TAG, "Supplied file " + fileUri + " is not a valid temp file to resume");
	setResultCode(RESULT_TEMP_FILE_GENERATION_ERROR);
	continue;
	}
	File tempFile = new File(fileUri.getSchemeSpecificPart());
	if (!tempFile.exists()) {
	Log.w(LOG_TAG, "Supplied file " + fileUri + " does not exist.");
	setResultCode(RESULT_TEMP_FILE_GENERATION_ERROR);
	continue;
	}
	Uri contentUri = MbmsTempFileProvider.getUriForFile(
	context, getFileProviderAuthorityCached(context), tempFile);
	context.grantUriPermission(getMiddlewarePackageCached(context), contentUri,
	Intent.FLAG_GRANT_READ_URI_PERMISSION \| Intent.FLAG_GRANT_WRITE_URI_PERMISSION);

	result.add(new UriPathPair(fileUri, contentUri));
	}
	return result;
	}

	private void cleanupTempFiles(Context context, Intent intent) {
	String serviceId = intent.getStringExtra(VendorUtils.EXTRA_SERVICE_ID);
	File tempFileDir = MbmsUtils.getEmbmsTempFileDirForService(context, serviceId);
	final List<Uri> filesInUse =
	intent.getParcelableArrayListExtra(VendorUtils.EXTRA_TEMP_FILES_IN_USE, android.net.Uri.class);
	File[] filesToDelete = tempFileDir.listFiles(new FileFilter() {
	@Override
	public boolean accept(File file) {
	File canonicalFile;
	try {
	canonicalFile = file.getCanonicalFile();
	} catch (IOException e) {
	Log.w(LOG_TAG, "Got IOException canonicalizing " + file + ", not deleting.");
	return false;
	}
	// Reject all files that don't match what we think a temp file should look like
	// e.g. download tokens
	if (!canonicalFile.getName().endsWith(TEMP_FILE_SUFFIX)) {
	return false;
	}
	// If any of the files in use match the uri, return false to reject it from the
	// list to delete.
	Uri fileInUseUri = Uri.fromFile(canonicalFile);
	return !filesInUse.contains(fileInUseUri);
	}
	});
	for (File fileToDelete : filesToDelete) {
	fileToDelete.delete();
	}
	}

	/*
	* Moves a tempfile located at fromPath to its final home where the app wants it
	*/
	private static Uri moveToFinalLocation(Uri fromPath, Path appSpecifiedPath,
	String relativeLocation) throws IOException {
	if (!ContentResolver.SCHEME_FILE.equals(fromPath.getScheme())) {
	Log.w(LOG_TAG, "Downloaded file location uri " + fromPath +
	" does not have a file scheme");
	return null;
	}

	Path fromFile = FileSystems.getDefault().getPath(fromPath.getPath());
	Path toFile = appSpecifiedPath.resolve(relativeLocation);

	if (!Files.isDirectory(toFile.getParent())) {
	Files.createDirectories(toFile.getParent());
	}
	Path result = Files.move(fromFile, toFile,
	StandardCopyOption.REPLACE_EXISTING, StandardCopyOption.ATOMIC_MOVE);

	return Uri.fromFile(result.toFile());
	}

	/**
	* @hide
	*/
	@VisibleForTesting
	public static String getFileRelativePath(String sourceUriPath, String fileInfoPath) {
	if (sourceUriPath.endsWith("*")) {
	// This is a wildcard path. Strip the last path component and use that as the root of
	// the relative path.
	int lastSlash = sourceUriPath.lastIndexOf('/');
	sourceUriPath = sourceUriPath.substring(0, lastSlash);
	}
	if (!fileInfoPath.startsWith(sourceUriPath)) {
	Log.e(LOG_TAG, "File location specified in FileInfo does not match the source URI."
	+ " source: " + sourceUriPath + " fileinfo path: " + fileInfoPath);
	return null;
	}
	if (fileInfoPath.length() == sourceUriPath.length()) {
	// This is the single-file download case. Return the name of the file so that the
	// receiver puts the file directly into the dest directory.
	return sourceUriPath.substring(sourceUriPath.lastIndexOf('/') + 1);
	}

	String prefixOmittedPath = fileInfoPath.substring(sourceUriPath.length());
	if (prefixOmittedPath.startsWith("/")) {
	prefixOmittedPath = prefixOmittedPath.substring(1);
	}
	return prefixOmittedPath;
	}

	private static boolean verifyTempFilePath(Context context, String serviceId,
	Uri filePath) {
	if (!ContentResolver.SCHEME_FILE.equals(filePath.getScheme())) {
	Log.w(LOG_TAG, "Uri " + filePath + " does not have a file scheme");
	return false;
	}

	String path = filePath.getSchemeSpecificPart();
	File tempFile = new File(path);
	if (!tempFile.exists()) {
	Log.w(LOG_TAG, "File at " + path + " does not exist.");
	return false;
	}

	if (!MbmsUtils.isContainedIn(
	MbmsUtils.getEmbmsTempFileDirForService(context, serviceId), tempFile)) {
	Log.w(LOG_TAG, "File at " + path + " is not contained in the temp file root," +
	" which is " + MbmsUtils.getEmbmsTempFileDirForService(context, serviceId));
	return false;
	}

	return true;
	}

	private String getFileProviderAuthorityCached(Context context) {
	if (mFileProviderAuthorityCache != null) {
	return mFileProviderAuthorityCache;
	}

	mFileProviderAuthorityCache = getFileProviderAuthority(context);
	return mFileProviderAuthorityCache;
	}

	private static String getFileProviderAuthority(Context context) {
	ApplicationInfo appInfo;
	try {
	appInfo = context.getPackageManager()
	.getApplicationInfo(context.getPackageName(), PackageManager.GET_META_DATA);
	} catch (PackageManager.NameNotFoundException e) {
	throw new RuntimeException("Package manager couldn't find " + context.getPackageName());
	}
	if (appInfo.metaData == null) {
	throw new RuntimeException("App must declare the file provider authority as metadata " +
	"in the manifest.");
	}
	String authority = appInfo.metaData.getString(MBMS_FILE_PROVIDER_META_DATA_KEY);
	if (authority == null) {
	throw new RuntimeException("App must declare the file provider authority as metadata " +
	"in the manifest.");
	}
	return authority;
	}

	private String getMiddlewarePackageCached(Context context) {
	if (mMiddlewarePackageNameCache == null) {
	mMiddlewarePackageNameCache = MbmsUtils.getMiddlewareServiceInfo(context,
	MbmsDownloadSession.MBMS_DOWNLOAD_SERVICE_ACTION).packageName;
	}
	return mMiddlewarePackageNameCache;
	}

	private void verifyPermissionIntegrity(Context context) {
	PackageManager pm = context.getPackageManager();
	Intent queryIntent = new Intent(context, MbmsDownloadReceiver.class);
	List<ResolveInfo> infos = pm.queryBroadcastReceivers(queryIntent, 0);
	if (infos.size() != 1) {
	throw new IllegalStateException("Non-unique download receiver in your app");
	}
	ActivityInfo selfInfo = infos.get(0).activityInfo;
	if (selfInfo == null) {
	throw new IllegalStateException("Queried ResolveInfo does not contain a receiver");
	}
	if (MbmsUtils.getOverrideServiceName(context,
	MbmsDownloadSession.MBMS_DOWNLOAD_SERVICE_ACTION) != null) {
	// If an override was specified, just make sure that the permission isn't null.
	if (selfInfo.permission == null) {
	throw new IllegalStateException(
	"MbmsDownloadReceiver must require some permission");
	}
	return;
	}
	if (!Objects.equals(EMBMS_INTENT_PERMISSION, selfInfo.permission)) {
	throw new IllegalStateException("MbmsDownloadReceiver must require the " +
	"SEND_EMBMS_INTENTS permission.");
	}
	}
	}