telephony/java/android/telephony/mbms/MbmsDownloadReceiver.java - platform/frameworks/base - 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.content.BroadcastReceiver;
 import android.content.ContentResolver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.net.Uri;
 import android.os.Bundle;
 import android.telephony.MbmsDownloadManager;
 import android.telephony.mbms.vendor.VendorIntents;
 import android.util.Log;

 import java.io.File;
 import java.io.FileFilter;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
 import java.util.UUID;

 /**
  * @hide
  */
 public class MbmsDownloadReceiver extends BroadcastReceiver {
     public static final String DOWNLOAD_TOKEN_SUFFIX = ".download_token";
     public static final String MBMS_FILE_PROVIDER_META_DATA_KEY = "mbms-file-provider-authority";

     /**
      * TODO: @SystemApi all these result codes
      * Indicates that the requested operation completed without error.
      */
     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 VendorIntents#ACTION_DOWNLOAD_RESULT_INTERNAL},
      * {@link VendorIntents#ACTION_FILE_DESCRIPTOR_REQUEST}, or
      * {@link VendorIntents#ACTION_CLEANUP}.
      * This is a fatal result code and no result extras should be expected.
      */
     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.
      */
     public static final int RESULT_MALFORMED_INTENT = 2;

     /**
      * Indicates that the supplied value for {@link VendorIntents#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.
      */
     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.
      */
     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.
      */
     public static final int RESULT_TEMP_FILE_GENERATION_ERROR = 5;

     private static final String LOG_TAG = "MbmsDownloadReceiver";
     private static final String TEMP_FILE_SUFFIX = ".embms.temp";
     private static final int MAX_TEMP_FILE_RETRIES = 5;


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

     @Override
     public void onReceive(Context context, Intent intent) {
         if (!verifyIntentContents(context, intent)) {
             setResultCode(RESULT_MALFORMED_INTENT);
             return;
         }
         if (!Objects.equals(intent.getStringExtra(VendorIntents.EXTRA_TEMP_FILE_ROOT),
                 MbmsTempFileProvider.getEmbmsTempFileDir(context).getPath())) {
             setResultCode(RESULT_BAD_TEMP_FILE_ROOT);
             return;
         }

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

     private boolean verifyIntentContents(Context context, Intent intent) {
         if (VendorIntents.ACTION_DOWNLOAD_RESULT_INTERNAL.equals(intent.getAction())) {
             if (!intent.hasExtra(MbmsDownloadManager.EXTRA_RESULT)) {
                 Log.w(LOG_TAG, "Download result did not include a result code. Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(VendorIntents.EXTRA_REQUEST)) {
                 Log.w(LOG_TAG, "Download result did not include the associated request. Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(VendorIntents.EXTRA_TEMP_FILE_ROOT)) {
                 Log.w(LOG_TAG, "Download result did not include the temp file root. Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(MbmsDownloadManager.EXTRA_FILE_INFO)) {
                 Log.w(LOG_TAG, "Download result did not include the associated file info. " +
                         "Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(VendorIntents.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(VendorIntents.EXTRA_REQUEST);
             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 (VendorIntents.ACTION_FILE_DESCRIPTOR_REQUEST.equals(intent.getAction())) {
             if (!intent.hasExtra(VendorIntents.EXTRA_SERVICE_INFO)) {
                 Log.w(LOG_TAG, "Temp file request did not include the associated service info." +
                         " Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(VendorIntents.EXTRA_TEMP_FILE_ROOT)) {
                 Log.w(LOG_TAG, "Download result did not include the temp file root. Ignoring.");
                 return false;
             }
         } else if (VendorIntents.ACTION_CLEANUP.equals(intent.getAction())) {
             if (!intent.hasExtra(VendorIntents.EXTRA_SERVICE_INFO)) {
                 Log.w(LOG_TAG, "Cleanup request did not include the associated service info." +
                         " Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(VendorIntents.EXTRA_TEMP_FILE_ROOT)) {
                 Log.w(LOG_TAG, "Cleanup request did not include the temp file root. Ignoring.");
                 return false;
             }
             if (!intent.hasExtra(VendorIntents.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(VendorIntents.EXTRA_REQUEST);
         Intent intentForApp = request.getIntentForApp();

         int result = intent.getIntExtra(MbmsDownloadManager.EXTRA_RESULT,
                 MbmsDownloadManager.RESULT_CANCELLED);
         intentForApp.putExtra(MbmsDownloadManager.EXTRA_RESULT, result);

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

         Uri destinationUri = request.getDestinationUri();
         Uri finalTempFile = intent.getParcelableExtra(VendorIntents.EXTRA_FINAL_URI);
         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(MbmsDownloadManager.EXTRA_FILE_INFO);
         String relativePath = calculateDestinationFileRelativePath(request, completedFileInfo);

         Uri finalFileLocation = moveTempFile(finalTempFile, destinationUri, relativePath);
         if (finalFileLocation == null) {
             Log.w(LOG_TAG, "Failed to move temp file to final destination");
             setResultCode(RESULT_DOWNLOAD_FINALIZATION_ERROR);
             return;
         }
         intentForApp.putExtra(MbmsDownloadManager.EXTRA_COMPLETED_FILE_URI, finalFileLocation);
         intentForApp.putExtra(MbmsDownloadManager.EXTRA_FILE_INFO, completedFileInfo);

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

     private void cleanupPostMove(Context context, Intent intent) {
         DownloadRequest request = intent.getParcelableExtra(VendorIntents.EXTRA_REQUEST);
         if (request == null) {
             Log.w(LOG_TAG, "Intent does not include a DownloadRequest. Ignoring.");
             return;
         }

         List<Uri> tempFiles = intent.getParcelableExtra(VendorIntents.EXTRA_TEMP_LIST);
         if (tempFiles == null) {
             return;
         }

         for (Uri tempFileUri : tempFiles) {
             if (verifyTempFilePath(context, request.getFileServiceId(), tempFileUri)) {
                 File tempFile = new File(tempFileUri.getSchemeSpecificPart());
                 tempFile.delete();
             }
         }
     }

     private void generateTempFiles(Context context, Intent intent) {
         FileServiceInfo serviceInfo =
                 intent.getParcelableExtra(VendorIntents.EXTRA_SERVICE_INFO);
         if (serviceInfo == null) {
             Log.w(LOG_TAG, "Temp file request did not include the associated service info. " +
                     "Ignoring.");
             setResultCode(RESULT_MALFORMED_INTENT);
             return;
         }
         int fdCount = intent.getIntExtra(VendorIntents.EXTRA_FD_COUNT, 0);
         List<Uri> pausedList = intent.getParcelableExtra(VendorIntents.EXTRA_PAUSED_LIST);

         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, serviceInfo, fdCount);
         ArrayList<UriPathPair> pausedFiles =
                 generateUrisForPausedFiles(context, serviceInfo, pausedList);

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

     private ArrayList<UriPathPair> generateFreshTempFiles(Context context,
             FileServiceInfo serviceInfo,
             int freshFdCount) {
         File tempFileDir = MbmsUtils.getEmbmsTempFileDirForService(context,
                 serviceInfo.getServiceId());
         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,
             FileServiceInfo serviceInfo, List<Uri> pausedFiles) {
         if (pausedFiles == null) {
             return new ArrayList<>(0);
         }
         ArrayList<UriPathPair> result = new ArrayList<>(pausedFiles.size());

         for (Uri fileUri : pausedFiles) {
             if (!verifyTempFilePath(context, serviceInfo.getServiceId(), 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) {
         FileServiceInfo serviceInfo =
                 intent.getParcelableExtra(VendorIntents.EXTRA_SERVICE_INFO);
         File tempFileDir = MbmsUtils.getEmbmsTempFileDirForService(context,
                 serviceInfo.getServiceId());
         final List<Uri> filesInUse =
                 intent.getParcelableArrayListExtra(VendorIntents.EXTRA_TEMP_FILES_IN_USE);
         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();
         }
     }

     private static String calculateDestinationFileRelativePath(DownloadRequest request,
             FileInfo info) {
         List<String> filePathComponents = info.getUri().getPathSegments();
         List<String> requestPathComponents = request.getSourceUri().getPathSegments();
         Iterator<String> filePathIter = filePathComponents.iterator();
         Iterator<String> requestPathIter = requestPathComponents.iterator();

         StringBuilder pathBuilder = new StringBuilder();
         // Iterate through the segments of the carrier's URI to the file, along with the segments
         // of the source URI specified in the download request. The relative path is calculated
         // as the tail of the file's URI that does not match the path segments in the source URI.
         while (filePathIter.hasNext()) {
             String currFilePathComponent = filePathIter.next();
             if (requestPathIter.hasNext()) {
                 String requestFilePathComponent = requestPathIter.next();
                 if (requestFilePathComponent.equals(currFilePathComponent)) {
                     continue;
                 }
             }
             pathBuilder.append(currFilePathComponent);
             pathBuilder.append('/');
         }
         // remove the trailing slash
         if (pathBuilder.length() > 0) {
             pathBuilder.deleteCharAt(pathBuilder.length() - 1);
         }
         return pathBuilder.toString();
     }

     /*
      * Moves a tempfile located at fromPath to a new location at toPath. If
      * toPath is a directory, the destination file will be located at  relativePath
      * underneath toPath.
      */
     private static Uri moveTempFile(Uri fromPath, Uri toPath, String relativePath) {
         if (!ContentResolver.SCHEME_FILE.equals(fromPath.getScheme())) {
             Log.w(LOG_TAG, "Moving source uri " + fromPath+ " does not have a file scheme");
             return null;
         }
         if (!ContentResolver.SCHEME_FILE.equals(toPath.getScheme())) {
             Log.w(LOG_TAG, "Moving destination uri " + toPath + " does not have a file scheme");
             return null;
         }

         File fromFile = new File(fromPath.getSchemeSpecificPart());
         File toFile = new File(toPath.getSchemeSpecificPart());
         if (toFile.isDirectory()) {
             toFile = new File(toFile, relativePath);
         }
         toFile.getParentFile().mkdirs();

         if (fromFile.renameTo(toFile)) {
             return Uri.fromFile(toFile);
         } else if (manualMove(fromFile, toFile)) {
             return Uri.fromFile(toFile);
         }
         return null;
     }

     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)) {
             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());
         }
         String authority = appInfo.metaData.getString(MBMS_FILE_PROVIDER_META_DATA_KEY);
         if (authority == null) {
             throw new RuntimeException("Must declare the file provider authority as meta data");
         }
         return authority;
     }

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

     private static boolean manualMove(File src, File dst) {
         InputStream in = null;
         OutputStream out = null;
         try {
             if (!dst.exists()) {
                 dst.createNewFile();
             }
             in = new FileInputStream(src);
             out = new FileOutputStream(dst);
             byte[] buffer = new byte[2048];
             int len;
             do {
                 len = in.read(buffer);
                 out.write(buffer, 0, len);
             } while (len > 0);
         } catch (IOException e) {
             Log.w(LOG_TAG, "Manual file move failed due to exception "  + e);
             if (dst.exists()) {
                 dst.delete();
             }
             return false;
         } finally {
             try {
                 if (in != null) {
                     in.close();
                 }
                 if (out != null) {
                     out.close();
                 }
             } catch (IOException e) {
                 Log.w(LOG_TAG, "Error closing streams: " + e);
             }
         }
         return true;
     }
 }
	/*
	* 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.content.BroadcastReceiver;
	import android.content.ContentResolver;
	import android.content.Context;
	import android.content.Intent;
	import android.content.pm.ApplicationInfo;
	import android.content.pm.PackageManager;
	import android.net.Uri;
	import android.os.Bundle;
	import android.telephony.MbmsDownloadManager;
	import android.telephony.mbms.vendor.VendorIntents;
	import android.util.Log;

	import java.io.File;
	import java.io.FileFilter;
	import java.io.FileInputStream;
	import java.io.FileOutputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;
	import java.util.ArrayList;
	import java.util.Iterator;
	import java.util.List;
	import java.util.Objects;
	import java.util.UUID;

	/**
	* @hide
	*/
	public class MbmsDownloadReceiver extends BroadcastReceiver {
	public static final String DOWNLOAD_TOKEN_SUFFIX = ".download_token";
	public static final String MBMS_FILE_PROVIDER_META_DATA_KEY = "mbms-file-provider-authority";

	/**
	* TODO: @SystemApi all these result codes
	* Indicates that the requested operation completed without error.
	*/
	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 VendorIntents#ACTION_DOWNLOAD_RESULT_INTERNAL},
	* {@link VendorIntents#ACTION_FILE_DESCRIPTOR_REQUEST}, or
	* {@link VendorIntents#ACTION_CLEANUP}.
	* This is a fatal result code and no result extras should be expected.
	*/
	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.
	*/
	public static final int RESULT_MALFORMED_INTENT = 2;

	/**
	* Indicates that the supplied value for {@link VendorIntents#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.
	*/
	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.
	*/
	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.
	*/
	public static final int RESULT_TEMP_FILE_GENERATION_ERROR = 5;

	private static final String LOG_TAG = "MbmsDownloadReceiver";
	private static final String TEMP_FILE_SUFFIX = ".embms.temp";
	private static final int MAX_TEMP_FILE_RETRIES = 5;


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

	@Override
	public void onReceive(Context context, Intent intent) {
	if (!verifyIntentContents(context, intent)) {
	setResultCode(RESULT_MALFORMED_INTENT);
	return;
	}
	if (!Objects.equals(intent.getStringExtra(VendorIntents.EXTRA_TEMP_FILE_ROOT),
	MbmsTempFileProvider.getEmbmsTempFileDir(context).getPath())) {
	setResultCode(RESULT_BAD_TEMP_FILE_ROOT);
	return;
	}

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

	private boolean verifyIntentContents(Context context, Intent intent) {
	if (VendorIntents.ACTION_DOWNLOAD_RESULT_INTERNAL.equals(intent.getAction())) {
	if (!intent.hasExtra(MbmsDownloadManager.EXTRA_RESULT)) {
	Log.w(LOG_TAG, "Download result did not include a result code. Ignoring.");
	return false;
	}
	if (!intent.hasExtra(VendorIntents.EXTRA_REQUEST)) {
	Log.w(LOG_TAG, "Download result did not include the associated request. Ignoring.");
	return false;
	}
	if (!intent.hasExtra(VendorIntents.EXTRA_TEMP_FILE_ROOT)) {
	Log.w(LOG_TAG, "Download result did not include the temp file root. Ignoring.");
	return false;
	}
	if (!intent.hasExtra(MbmsDownloadManager.EXTRA_FILE_INFO)) {
	Log.w(LOG_TAG, "Download result did not include the associated file info. " +
	"Ignoring.");
	return false;
	}
	if (!intent.hasExtra(VendorIntents.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(VendorIntents.EXTRA_REQUEST);
	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 (VendorIntents.ACTION_FILE_DESCRIPTOR_REQUEST.equals(intent.getAction())) {
	if (!intent.hasExtra(VendorIntents.EXTRA_SERVICE_INFO)) {
	Log.w(LOG_TAG, "Temp file request did not include the associated service info." +
	" Ignoring.");
	return false;
	}
	if (!intent.hasExtra(VendorIntents.EXTRA_TEMP_FILE_ROOT)) {
	Log.w(LOG_TAG, "Download result did not include the temp file root. Ignoring.");
	return false;
	}
	} else if (VendorIntents.ACTION_CLEANUP.equals(intent.getAction())) {
	if (!intent.hasExtra(VendorIntents.EXTRA_SERVICE_INFO)) {
	Log.w(LOG_TAG, "Cleanup request did not include the associated service info." +
	" Ignoring.");
	return false;
	}
	if (!intent.hasExtra(VendorIntents.EXTRA_TEMP_FILE_ROOT)) {
	Log.w(LOG_TAG, "Cleanup request did not include the temp file root. Ignoring.");
	return false;
	}
	if (!intent.hasExtra(VendorIntents.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(VendorIntents.EXTRA_REQUEST);
	Intent intentForApp = request.getIntentForApp();

	int result = intent.getIntExtra(MbmsDownloadManager.EXTRA_RESULT,
	MbmsDownloadManager.RESULT_CANCELLED);
	intentForApp.putExtra(MbmsDownloadManager.EXTRA_RESULT, result);

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

	Uri destinationUri = request.getDestinationUri();
	Uri finalTempFile = intent.getParcelableExtra(VendorIntents.EXTRA_FINAL_URI);
	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(MbmsDownloadManager.EXTRA_FILE_INFO);
	String relativePath = calculateDestinationFileRelativePath(request, completedFileInfo);

	Uri finalFileLocation = moveTempFile(finalTempFile, destinationUri, relativePath);
	if (finalFileLocation == null) {
	Log.w(LOG_TAG, "Failed to move temp file to final destination");
	setResultCode(RESULT_DOWNLOAD_FINALIZATION_ERROR);
	return;
	}
	intentForApp.putExtra(MbmsDownloadManager.EXTRA_COMPLETED_FILE_URI, finalFileLocation);
	intentForApp.putExtra(MbmsDownloadManager.EXTRA_FILE_INFO, completedFileInfo);

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

	private void cleanupPostMove(Context context, Intent intent) {
	DownloadRequest request = intent.getParcelableExtra(VendorIntents.EXTRA_REQUEST);
	if (request == null) {
	Log.w(LOG_TAG, "Intent does not include a DownloadRequest. Ignoring.");
	return;
	}

	List<Uri> tempFiles = intent.getParcelableExtra(VendorIntents.EXTRA_TEMP_LIST);
	if (tempFiles == null) {
	return;
	}

	for (Uri tempFileUri : tempFiles) {
	if (verifyTempFilePath(context, request.getFileServiceId(), tempFileUri)) {
	File tempFile = new File(tempFileUri.getSchemeSpecificPart());
	tempFile.delete();
	}
	}
	}

	private void generateTempFiles(Context context, Intent intent) {
	FileServiceInfo serviceInfo =
	intent.getParcelableExtra(VendorIntents.EXTRA_SERVICE_INFO);
	if (serviceInfo == null) {
	Log.w(LOG_TAG, "Temp file request did not include the associated service info. " +
	"Ignoring.");
	setResultCode(RESULT_MALFORMED_INTENT);
	return;
	}
	int fdCount = intent.getIntExtra(VendorIntents.EXTRA_FD_COUNT, 0);
	List<Uri> pausedList = intent.getParcelableExtra(VendorIntents.EXTRA_PAUSED_LIST);

	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, serviceInfo, fdCount);
	ArrayList<UriPathPair> pausedFiles =
	generateUrisForPausedFiles(context, serviceInfo, pausedList);

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

	private ArrayList<UriPathPair> generateFreshTempFiles(Context context,
	FileServiceInfo serviceInfo,
	int freshFdCount) {
	File tempFileDir = MbmsUtils.getEmbmsTempFileDirForService(context,
	serviceInfo.getServiceId());
	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,
	FileServiceInfo serviceInfo, List<Uri> pausedFiles) {
	if (pausedFiles == null) {
	return new ArrayList<>(0);
	}
	ArrayList<UriPathPair> result = new ArrayList<>(pausedFiles.size());

	for (Uri fileUri : pausedFiles) {
	if (!verifyTempFilePath(context, serviceInfo.getServiceId(), 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) {
	FileServiceInfo serviceInfo =
	intent.getParcelableExtra(VendorIntents.EXTRA_SERVICE_INFO);
	File tempFileDir = MbmsUtils.getEmbmsTempFileDirForService(context,
	serviceInfo.getServiceId());
	final List<Uri> filesInUse =
	intent.getParcelableArrayListExtra(VendorIntents.EXTRA_TEMP_FILES_IN_USE);
	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();
	}
	}

	private static String calculateDestinationFileRelativePath(DownloadRequest request,
	FileInfo info) {
	List<String> filePathComponents = info.getUri().getPathSegments();
	List<String> requestPathComponents = request.getSourceUri().getPathSegments();
	Iterator<String> filePathIter = filePathComponents.iterator();
	Iterator<String> requestPathIter = requestPathComponents.iterator();

	StringBuilder pathBuilder = new StringBuilder();
	// Iterate through the segments of the carrier's URI to the file, along with the segments
	// of the source URI specified in the download request. The relative path is calculated
	// as the tail of the file's URI that does not match the path segments in the source URI.
	while (filePathIter.hasNext()) {
	String currFilePathComponent = filePathIter.next();
	if (requestPathIter.hasNext()) {
	String requestFilePathComponent = requestPathIter.next();
	if (requestFilePathComponent.equals(currFilePathComponent)) {
	continue;
	}
	}
	pathBuilder.append(currFilePathComponent);
	pathBuilder.append('/');
	}
	// remove the trailing slash
	if (pathBuilder.length() > 0) {
	pathBuilder.deleteCharAt(pathBuilder.length() - 1);
	}
	return pathBuilder.toString();
	}

	/*
	* Moves a tempfile located at fromPath to a new location at toPath. If
	* toPath is a directory, the destination file will be located at relativePath
	* underneath toPath.
	*/
	private static Uri moveTempFile(Uri fromPath, Uri toPath, String relativePath) {
	if (!ContentResolver.SCHEME_FILE.equals(fromPath.getScheme())) {
	Log.w(LOG_TAG, "Moving source uri " + fromPath+ " does not have a file scheme");
	return null;
	}
	if (!ContentResolver.SCHEME_FILE.equals(toPath.getScheme())) {
	Log.w(LOG_TAG, "Moving destination uri " + toPath + " does not have a file scheme");
	return null;
	}

	File fromFile = new File(fromPath.getSchemeSpecificPart());
	File toFile = new File(toPath.getSchemeSpecificPart());
	if (toFile.isDirectory()) {
	toFile = new File(toFile, relativePath);
	}
	toFile.getParentFile().mkdirs();

	if (fromFile.renameTo(toFile)) {
	return Uri.fromFile(toFile);
	} else if (manualMove(fromFile, toFile)) {
	return Uri.fromFile(toFile);
	}
	return null;
	}

	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)) {
	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());
	}
	String authority = appInfo.metaData.getString(MBMS_FILE_PROVIDER_META_DATA_KEY);
	if (authority == null) {
	throw new RuntimeException("Must declare the file provider authority as meta data");
	}
	return authority;
	}

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

	private static boolean manualMove(File src, File dst) {
	InputStream in = null;
	OutputStream out = null;
	try {
	if (!dst.exists()) {
	dst.createNewFile();
	}
	in = new FileInputStream(src);
	out = new FileOutputStream(dst);
	byte[] buffer = new byte[2048];
	int len;
	do {
	len = in.read(buffer);
	out.write(buffer, 0, len);
	} while (len > 0);
	} catch (IOException e) {
	Log.w(LOG_TAG, "Manual file move failed due to exception " + e);
	if (dst.exists()) {
	dst.delete();
	}
	return false;
	} finally {
	try {
	if (in != null) {
	in.close();
	}
	if (out != null) {
	out.close();
	}
	} catch (IOException e) {
	Log.w(LOG_TAG, "Error closing streams: " + e);
	}
	}
	return true;
	}
	}