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1 /*
2  * Copyright (C) 2008 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.providers.downloads;
18 
19 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_METERED;
20 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_ROAMING;
21 import static android.provider.Downloads.Impl.COLUMN_CONTROL;
22 import static android.provider.Downloads.Impl.COLUMN_DELETED;
23 import static android.provider.Downloads.Impl.COLUMN_STATUS;
24 import static android.provider.Downloads.Impl.CONTROL_PAUSED;
25 import static android.provider.Downloads.Impl.STATUS_BAD_REQUEST;
26 import static android.provider.Downloads.Impl.STATUS_CANCELED;
27 import static android.provider.Downloads.Impl.STATUS_CANNOT_RESUME;
28 import static android.provider.Downloads.Impl.STATUS_FILE_ERROR;
29 import static android.provider.Downloads.Impl.STATUS_HTTP_DATA_ERROR;
30 import static android.provider.Downloads.Impl.STATUS_INSUFFICIENT_SPACE_ERROR;
31 import static android.provider.Downloads.Impl.STATUS_PAUSED_BY_APP;
32 import static android.provider.Downloads.Impl.STATUS_QUEUED_FOR_WIFI;
33 import static android.provider.Downloads.Impl.STATUS_RUNNING;
34 import static android.provider.Downloads.Impl.STATUS_SUCCESS;
35 import static android.provider.Downloads.Impl.STATUS_TOO_MANY_REDIRECTS;
36 import static android.provider.Downloads.Impl.STATUS_UNHANDLED_HTTP_CODE;
37 import static android.provider.Downloads.Impl.STATUS_UNKNOWN_ERROR;
38 import static android.provider.Downloads.Impl.STATUS_WAITING_FOR_NETWORK;
39 import static android.provider.Downloads.Impl.STATUS_WAITING_TO_RETRY;
40 import static android.text.format.DateUtils.SECOND_IN_MILLIS;
41 
42 import static com.android.providers.downloads.Constants.TAG;
43 
44 import static java.net.HttpURLConnection.HTTP_INTERNAL_ERROR;
45 import static java.net.HttpURLConnection.HTTP_MOVED_PERM;
46 import static java.net.HttpURLConnection.HTTP_MOVED_TEMP;
47 import static java.net.HttpURLConnection.HTTP_OK;
48 import static java.net.HttpURLConnection.HTTP_PARTIAL;
49 import static java.net.HttpURLConnection.HTTP_PRECON_FAILED;
50 import static java.net.HttpURLConnection.HTTP_SEE_OTHER;
51 import static java.net.HttpURLConnection.HTTP_UNAVAILABLE;
52 
53 import android.app.job.JobParameters;
54 import android.content.ContentValues;
55 import android.content.Context;
56 import android.content.Intent;
57 import android.drm.DrmManagerClient;
58 import android.drm.DrmOutputStream;
59 import android.net.ConnectivityManager;
60 import android.net.INetworkPolicyListener;
61 import android.net.Network;
62 import android.net.NetworkCapabilities;
63 import android.net.NetworkInfo;
64 import android.net.NetworkPolicyManager;
65 import android.net.TrafficStats;
66 import android.net.Uri;
67 import android.os.ParcelFileDescriptor;
68 import android.os.Process;
69 import android.os.SystemClock;
70 import android.os.storage.StorageManager;
71 import android.provider.Downloads;
72 import android.system.ErrnoException;
73 import android.system.Os;
74 import android.system.OsConstants;
75 import android.util.Log;
76 import android.util.MathUtils;
77 import android.util.Pair;
78 
79 import libcore.io.IoUtils;
80 
81 import java.io.File;
82 import java.io.FileDescriptor;
83 import java.io.FileNotFoundException;
84 import java.io.IOException;
85 import java.io.InputStream;
86 import java.io.OutputStream;
87 import java.net.HttpURLConnection;
88 import java.net.MalformedURLException;
89 import java.net.ProtocolException;
90 import java.net.URL;
91 import java.net.URLConnection;
92 import java.security.GeneralSecurityException;
93 
94 import javax.net.ssl.HttpsURLConnection;
95 import javax.net.ssl.SSLContext;
96 
97 /**
98  * Task which executes a given {@link DownloadInfo}: making network requests,
99  * persisting data to disk, and updating {@link DownloadProvider}.
100  * <p>
101  * To know if a download is successful, we need to know either the final content
102  * length to expect, or the transfer to be chunked. To resume an interrupted
103  * download, we need an ETag.
104  * <p>
105  * Failed network requests are retried several times before giving up. Local
106  * disk errors fail immediately and are not retried.
107  */
108 public class DownloadThread extends Thread {
109 
110     // TODO: bind each download to a specific network interface to avoid state
111     // checking races once we have ConnectivityManager API
112 
113     // TODO: add support for saving to content://
114 
115     private static final int HTTP_REQUESTED_RANGE_NOT_SATISFIABLE = 416;
116     private static final int HTTP_TEMP_REDIRECT = 307;
117 
118     private static final int DEFAULT_TIMEOUT = (int) (20 * SECOND_IN_MILLIS);
119 
120     private final Context mContext;
121     private final SystemFacade mSystemFacade;
122     private final DownloadNotifier mNotifier;
123     private final NetworkPolicyManager mNetworkPolicy;
124     private final StorageManager mStorage;
125 
126     private final DownloadJobService mJobService;
127     private final JobParameters mParams;
128 
129     private final long mId;
130 
131     /**
132      * Info object that should be treated as read-only. Any potentially mutated
133      * fields are tracked in {@link #mInfoDelta}. If a field exists in
134      * {@link #mInfoDelta}, it must not be read from {@link #mInfo}.
135      */
136     private final DownloadInfo mInfo;
137     private final DownloadInfoDelta mInfoDelta;
138 
139     private volatile boolean mPolicyDirty;
140 
141     /**
142      * Local changes to {@link DownloadInfo}. These are kept local to avoid
143      * racing with the thread that updates based on change notifications.
144      */
145     private class DownloadInfoDelta {
146         public String mUri;
147         public String mFileName;
148         public String mMimeType;
149         public int mStatus;
150         public int mNumFailed;
151         public int mRetryAfter;
152         public long mTotalBytes;
153         public long mCurrentBytes;
154         public String mETag;
155 
156         public String mErrorMsg;
157 
158         private static final String NOT_CANCELED = COLUMN_STATUS + " != '" + STATUS_CANCELED + "'";
159         private static final String NOT_DELETED = COLUMN_DELETED + " == '0'";
160         private static final String NOT_PAUSED = "(" + COLUMN_CONTROL + " IS NULL OR "
161                 + COLUMN_CONTROL + " != '" + CONTROL_PAUSED + "')";
162 
163         private static final String SELECTION_VALID = NOT_CANCELED + " AND " + NOT_DELETED + " AND "
164                 + NOT_PAUSED;
165 
DownloadInfoDelta(DownloadInfo info)166         public DownloadInfoDelta(DownloadInfo info) {
167             mUri = info.mUri;
168             mFileName = info.mFileName;
169             mMimeType = info.mMimeType;
170             mStatus = info.mStatus;
171             mNumFailed = info.mNumFailed;
172             mRetryAfter = info.mRetryAfter;
173             mTotalBytes = info.mTotalBytes;
174             mCurrentBytes = info.mCurrentBytes;
175             mETag = info.mETag;
176         }
177 
buildContentValues()178         private ContentValues buildContentValues() {
179             final ContentValues values = new ContentValues();
180 
181             values.put(Downloads.Impl.COLUMN_URI, mUri);
182             values.put(Downloads.Impl._DATA, mFileName);
183             values.put(Downloads.Impl.COLUMN_MIME_TYPE, mMimeType);
184             values.put(Downloads.Impl.COLUMN_STATUS, mStatus);
185             values.put(Downloads.Impl.COLUMN_FAILED_CONNECTIONS, mNumFailed);
186             values.put(Constants.RETRY_AFTER_X_REDIRECT_COUNT, mRetryAfter);
187             values.put(Downloads.Impl.COLUMN_TOTAL_BYTES, mTotalBytes);
188             values.put(Downloads.Impl.COLUMN_CURRENT_BYTES, mCurrentBytes);
189             values.put(Constants.ETAG, mETag);
190 
191             values.put(Downloads.Impl.COLUMN_LAST_MODIFICATION, mSystemFacade.currentTimeMillis());
192             values.put(Downloads.Impl.COLUMN_ERROR_MSG, mErrorMsg);
193 
194             return values;
195         }
196 
197         /**
198          * Blindly push update of current delta values to provider.
199          */
writeToDatabase()200         public void writeToDatabase() {
201             mContext.getContentResolver().update(mInfo.getAllDownloadsUri(), buildContentValues(),
202                     null, null);
203         }
204 
205         /**
206          * Push update of current delta values to provider, asserting strongly
207          * that we haven't been paused or deleted.
208          */
writeToDatabaseOrThrow()209         public void writeToDatabaseOrThrow() throws StopRequestException {
210             if (mContext.getContentResolver().update(mInfo.getAllDownloadsUri(),
211                     buildContentValues(), SELECTION_VALID, null) == 0) {
212                 if (mInfo.queryDownloadControl() == CONTROL_PAUSED) {
213                     throw new StopRequestException(STATUS_PAUSED_BY_APP, "Download paused!");
214                 } else {
215                     throw new StopRequestException(STATUS_CANCELED, "Download deleted or missing!");
216                 }
217             }
218         }
219     }
220 
221     /**
222      * Flag indicating if we've made forward progress transferring file data
223      * from a remote server.
224      */
225     private boolean mMadeProgress = false;
226 
227     /**
228      * Details from the last time we pushed a database update.
229      */
230     private long mLastUpdateBytes = 0;
231     private long mLastUpdateTime = 0;
232 
233     private boolean mIgnoreBlocked;
234     private Network mNetwork;
235 
236     private int mNetworkType = ConnectivityManager.TYPE_NONE;
237 
238     /** Historical bytes/second speed of this download. */
239     private long mSpeed;
240     /** Time when current sample started. */
241     private long mSpeedSampleStart;
242     /** Bytes transferred since current sample started. */
243     private long mSpeedSampleBytes;
244 
245     /** Flag indicating that thread must be halted */
246     private volatile boolean mShutdownRequested;
247 
DownloadThread(DownloadJobService service, JobParameters params, DownloadInfo info)248     public DownloadThread(DownloadJobService service, JobParameters params, DownloadInfo info) {
249         mContext = service;
250         mSystemFacade = Helpers.getSystemFacade(mContext);
251         mNotifier = Helpers.getDownloadNotifier(mContext);
252         mNetworkPolicy = mContext.getSystemService(NetworkPolicyManager.class);
253         mStorage = mContext.getSystemService(StorageManager.class);
254 
255         mJobService = service;
256         mParams = params;
257 
258         mId = info.mId;
259         mInfo = info;
260         mInfoDelta = new DownloadInfoDelta(info);
261     }
262 
263     @Override
run()264     public void run() {
265         Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
266 
267         // Skip when download already marked as finished; this download was
268         // probably started again while racing with UpdateThread.
269         if (mInfo.queryDownloadStatus() == Downloads.Impl.STATUS_SUCCESS) {
270             logDebug("Already finished; skipping");
271             return;
272         }
273 
274         try {
275             // while performing download, register for rules updates
276             mNetworkPolicy.registerListener(mPolicyListener);
277 
278             logDebug("Starting");
279 
280             mInfoDelta.mStatus = STATUS_RUNNING;
281             mInfoDelta.writeToDatabase();
282 
283             // If we're showing a foreground notification for the requesting
284             // app, the download isn't affected by the blocked status of the
285             // requesting app
286             mIgnoreBlocked = mInfo.isVisible();
287 
288             // Use the caller's default network to make this connection, since
289             // they might be subject to restrictions that we shouldn't let them
290             // circumvent
291             mNetwork = mSystemFacade.getNetwork(mParams);
292             if (mNetwork == null) {
293                 throw new StopRequestException(STATUS_WAITING_FOR_NETWORK,
294                         "No network associated with requesting UID");
295             }
296 
297             // Remember which network this download started on; used to
298             // determine if errors were due to network changes.
299             final NetworkInfo info = mSystemFacade.getNetworkInfo(mNetwork, mInfo.mUid,
300                     mIgnoreBlocked);
301             if (info != null) {
302                 mNetworkType = info.getType();
303             }
304 
305             // Network traffic on this thread should be counted against the
306             // requesting UID, and is tagged with well-known value.
307             TrafficStats.setThreadStatsTag(TrafficStats.TAG_SYSTEM_DOWNLOAD);
308             TrafficStats.setThreadStatsUid(mInfo.mUid);
309 
310             executeDownload();
311 
312             mInfoDelta.mStatus = STATUS_SUCCESS;
313             TrafficStats.incrementOperationCount(1);
314 
315             // If we just finished a chunked file, record total size
316             if (mInfoDelta.mTotalBytes == -1) {
317                 mInfoDelta.mTotalBytes = mInfoDelta.mCurrentBytes;
318             }
319 
320         } catch (StopRequestException e) {
321             mInfoDelta.mStatus = e.getFinalStatus();
322             mInfoDelta.mErrorMsg = e.getMessage();
323 
324             logWarning("Stop requested with status "
325                     + Downloads.Impl.statusToString(mInfoDelta.mStatus) + ": "
326                     + mInfoDelta.mErrorMsg);
327 
328             // Nobody below our level should request retries, since we handle
329             // failure counts at this level.
330             if (mInfoDelta.mStatus == STATUS_WAITING_TO_RETRY) {
331                 throw new IllegalStateException("Execution should always throw final error codes");
332             }
333 
334             // Some errors should be retryable, unless we fail too many times.
335             if (isStatusRetryable(mInfoDelta.mStatus)) {
336                 if (mMadeProgress) {
337                     mInfoDelta.mNumFailed = 1;
338                 } else {
339                     mInfoDelta.mNumFailed += 1;
340                 }
341 
342                 if (mInfoDelta.mNumFailed < Constants.MAX_RETRIES) {
343                     final NetworkInfo info = mSystemFacade.getNetworkInfo(mNetwork, mInfo.mUid,
344                             mIgnoreBlocked);
345                     if (info != null && info.getType() == mNetworkType && info.isConnected()) {
346                         // Underlying network is still intact, use normal backoff
347                         mInfoDelta.mStatus = STATUS_WAITING_TO_RETRY;
348                     } else {
349                         // Network changed, retry on any next available
350                         mInfoDelta.mStatus = STATUS_WAITING_FOR_NETWORK;
351                     }
352 
353                     if ((mInfoDelta.mETag == null && mMadeProgress)
354                             || DownloadDrmHelper.isDrmConvertNeeded(mInfoDelta.mMimeType)) {
355                         // However, if we wrote data and have no ETag to verify
356                         // contents against later, we can't actually resume.
357                         mInfoDelta.mStatus = STATUS_CANNOT_RESUME;
358                     }
359                 }
360             }
361 
362             // If we're waiting for a network that must be unmetered, our status
363             // is actually queued so we show relevant notifications
364             if (mInfoDelta.mStatus == STATUS_WAITING_FOR_NETWORK
365                     && !mInfo.isMeteredAllowed(mInfoDelta.mTotalBytes)) {
366                 mInfoDelta.mStatus = STATUS_QUEUED_FOR_WIFI;
367             }
368 
369         } catch (Throwable t) {
370             mInfoDelta.mStatus = STATUS_UNKNOWN_ERROR;
371             mInfoDelta.mErrorMsg = t.toString();
372 
373             logError("Failed: " + mInfoDelta.mErrorMsg, t);
374 
375         } finally {
376             logDebug("Finished with status " + Downloads.Impl.statusToString(mInfoDelta.mStatus));
377 
378             mNotifier.notifyDownloadSpeed(mId, 0);
379 
380             finalizeDestination();
381 
382             mInfoDelta.writeToDatabase();
383 
384             TrafficStats.clearThreadStatsTag();
385             TrafficStats.clearThreadStatsUid();
386 
387             mNetworkPolicy.unregisterListener(mPolicyListener);
388         }
389 
390         boolean needsReschedule = false;
391         if (mInfoDelta.mStatus == STATUS_WAITING_TO_RETRY
392                 || mInfoDelta.mStatus == STATUS_WAITING_FOR_NETWORK
393                 || mInfoDelta.mStatus == STATUS_QUEUED_FOR_WIFI) {
394             needsReschedule = true;
395         }
396 
397         mJobService.jobFinishedInternal(mParams, needsReschedule);
398     }
399 
requestShutdown()400     public void requestShutdown() {
401         mShutdownRequested = true;
402     }
403 
404     /**
405      * Fully execute a single download request. Setup and send the request,
406      * handle the response, and transfer the data to the destination file.
407      */
executeDownload()408     private void executeDownload() throws StopRequestException {
409         final boolean resuming = mInfoDelta.mCurrentBytes != 0;
410 
411         URL url;
412         try {
413             // TODO: migrate URL sanity checking into client side of API
414             url = new URL(mInfoDelta.mUri);
415         } catch (MalformedURLException e) {
416             throw new StopRequestException(STATUS_BAD_REQUEST, e);
417         }
418 
419         boolean cleartextTrafficPermitted
420                 = mSystemFacade.isCleartextTrafficPermitted(mInfo.mPackage, url.getHost());
421         SSLContext appContext;
422         try {
423             appContext = mSystemFacade.getSSLContextForPackage(mContext, mInfo.mPackage);
424         } catch (GeneralSecurityException e) {
425             // This should never happen.
426             throw new StopRequestException(STATUS_UNKNOWN_ERROR, "Unable to create SSLContext.");
427         }
428         int redirectionCount = 0;
429         while (redirectionCount++ < Constants.MAX_REDIRECTS) {
430             // Enforce the cleartext traffic opt-out for the UID. This cannot be enforced earlier
431             // because of HTTP redirects which can change the protocol between HTTP and HTTPS.
432             if ((!cleartextTrafficPermitted) && ("http".equalsIgnoreCase(url.getProtocol()))) {
433                 throw new StopRequestException(STATUS_BAD_REQUEST,
434                         "Cleartext traffic not permitted for package " + mInfo.mPackage + ": "
435                         + Uri.parse(url.toString()).toSafeString());
436             }
437 
438             // Open connection and follow any redirects until we have a useful
439             // response with body.
440             HttpURLConnection conn = null;
441             try {
442                 // Check that the caller is allowed to make network connections. If so, make one on
443                 // their behalf to open the url.
444                 checkConnectivity();
445                 conn = (HttpURLConnection) mNetwork.openConnection(url);
446                 conn.setInstanceFollowRedirects(false);
447                 conn.setConnectTimeout(DEFAULT_TIMEOUT);
448                 conn.setReadTimeout(DEFAULT_TIMEOUT);
449                 // If this is going over HTTPS configure the trust to be the same as the calling
450                 // package.
451                 if (conn instanceof HttpsURLConnection) {
452                     ((HttpsURLConnection)conn).setSSLSocketFactory(appContext.getSocketFactory());
453                 }
454 
455                 addRequestHeaders(conn, resuming);
456 
457                 final int responseCode = conn.getResponseCode();
458                 switch (responseCode) {
459                     case HTTP_OK:
460                         if (resuming) {
461                             throw new StopRequestException(
462                                     STATUS_CANNOT_RESUME, "Expected partial, but received OK");
463                         }
464                         parseOkHeaders(conn);
465                         transferData(conn);
466                         return;
467 
468                     case HTTP_PARTIAL:
469                         if (!resuming) {
470                             throw new StopRequestException(
471                                     STATUS_CANNOT_RESUME, "Expected OK, but received partial");
472                         }
473                         transferData(conn);
474                         return;
475 
476                     case HTTP_MOVED_PERM:
477                     case HTTP_MOVED_TEMP:
478                     case HTTP_SEE_OTHER:
479                     case HTTP_TEMP_REDIRECT:
480                         final String location = conn.getHeaderField("Location");
481                         url = new URL(url, location);
482                         if (responseCode == HTTP_MOVED_PERM) {
483                             // Push updated URL back to database
484                             mInfoDelta.mUri = url.toString();
485                         }
486                         continue;
487 
488                     case HTTP_PRECON_FAILED:
489                         throw new StopRequestException(
490                                 STATUS_CANNOT_RESUME, "Precondition failed");
491 
492                     case HTTP_REQUESTED_RANGE_NOT_SATISFIABLE:
493                         throw new StopRequestException(
494                                 STATUS_CANNOT_RESUME, "Requested range not satisfiable");
495 
496                     case HTTP_UNAVAILABLE:
497                         parseUnavailableHeaders(conn);
498                         throw new StopRequestException(
499                                 HTTP_UNAVAILABLE, conn.getResponseMessage());
500 
501                     case HTTP_INTERNAL_ERROR:
502                         throw new StopRequestException(
503                                 HTTP_INTERNAL_ERROR, conn.getResponseMessage());
504 
505                     default:
506                         StopRequestException.throwUnhandledHttpError(
507                                 responseCode, conn.getResponseMessage());
508                 }
509 
510             } catch (IOException e) {
511                 if (e instanceof ProtocolException
512                         && e.getMessage().startsWith("Unexpected status line")) {
513                     throw new StopRequestException(STATUS_UNHANDLED_HTTP_CODE, e);
514                 } else {
515                     // Trouble with low-level sockets
516                     throw new StopRequestException(STATUS_HTTP_DATA_ERROR, e);
517                 }
518 
519             } finally {
520                 if (conn != null) conn.disconnect();
521             }
522         }
523 
524         throw new StopRequestException(STATUS_TOO_MANY_REDIRECTS, "Too many redirects");
525     }
526 
527     /**
528      * Transfer data from the given connection to the destination file.
529      */
transferData(HttpURLConnection conn)530     private void transferData(HttpURLConnection conn) throws StopRequestException {
531 
532         // To detect when we're really finished, we either need a length, closed
533         // connection, or chunked encoding.
534         final boolean hasLength = mInfoDelta.mTotalBytes != -1;
535         final boolean isConnectionClose = "close".equalsIgnoreCase(
536                 conn.getHeaderField("Connection"));
537         final boolean isEncodingChunked = "chunked".equalsIgnoreCase(
538                 conn.getHeaderField("Transfer-Encoding"));
539 
540         final boolean finishKnown = hasLength || isConnectionClose || isEncodingChunked;
541         if (!finishKnown) {
542             throw new StopRequestException(
543                     STATUS_CANNOT_RESUME, "can't know size of download, giving up");
544         }
545 
546         DrmManagerClient drmClient = null;
547         ParcelFileDescriptor outPfd = null;
548         FileDescriptor outFd = null;
549         InputStream in = null;
550         OutputStream out = null;
551         try {
552             try {
553                 in = conn.getInputStream();
554             } catch (IOException e) {
555                 throw new StopRequestException(STATUS_HTTP_DATA_ERROR, e);
556             }
557 
558             try {
559                 outPfd = mContext.getContentResolver()
560                         .openFileDescriptor(mInfo.getAllDownloadsUri(), "rw");
561                 outFd = outPfd.getFileDescriptor();
562 
563                 if (DownloadDrmHelper.isDrmConvertNeeded(mInfoDelta.mMimeType)) {
564                     drmClient = new DrmManagerClient(mContext);
565                     out = new DrmOutputStream(drmClient, outPfd, mInfoDelta.mMimeType);
566                 } else {
567                     out = new ParcelFileDescriptor.AutoCloseOutputStream(outPfd);
568                 }
569 
570                 // Move into place to begin writing
571                 Os.lseek(outFd, mInfoDelta.mCurrentBytes, OsConstants.SEEK_SET);
572             } catch (ErrnoException e) {
573                 throw new StopRequestException(STATUS_FILE_ERROR, e);
574             } catch (IOException e) {
575                 throw new StopRequestException(STATUS_FILE_ERROR, e);
576             }
577 
578             try {
579                 // Pre-flight disk space requirements, when known
580                 if (mInfoDelta.mTotalBytes > 0 && mStorage.isAllocationSupported(outFd)) {
581                     mStorage.allocateBytes(outFd, mInfoDelta.mTotalBytes);
582                 }
583             } catch (IOException e) {
584                 throw new StopRequestException(STATUS_INSUFFICIENT_SPACE_ERROR, e);
585             }
586 
587             // Start streaming data, periodically watch for pause/cancel
588             // commands and checking disk space as needed.
589             transferData(in, out, outFd);
590 
591             try {
592                 if (out instanceof DrmOutputStream) {
593                     ((DrmOutputStream) out).finish();
594                 }
595             } catch (IOException e) {
596                 throw new StopRequestException(STATUS_FILE_ERROR, e);
597             }
598 
599         } finally {
600             if (drmClient != null) {
601                 drmClient.close();
602             }
603 
604             IoUtils.closeQuietly(in);
605 
606             try {
607                 if (out != null) out.flush();
608                 if (outFd != null) outFd.sync();
609             } catch (IOException e) {
610             } finally {
611                 IoUtils.closeQuietly(out);
612             }
613         }
614     }
615 
616     /**
617      * Transfer as much data as possible from the HTTP response to the
618      * destination file.
619      */
transferData(InputStream in, OutputStream out, FileDescriptor outFd)620     private void transferData(InputStream in, OutputStream out, FileDescriptor outFd)
621             throws StopRequestException {
622         final byte buffer[] = new byte[Constants.BUFFER_SIZE];
623         while (true) {
624             if (mPolicyDirty) checkConnectivity();
625 
626             if (mShutdownRequested) {
627                 throw new StopRequestException(STATUS_HTTP_DATA_ERROR,
628                         "Local halt requested; job probably timed out");
629             }
630 
631             int len = -1;
632             try {
633                 len = in.read(buffer);
634             } catch (IOException e) {
635                 throw new StopRequestException(
636                         STATUS_HTTP_DATA_ERROR, "Failed reading response: " + e, e);
637             }
638 
639             if (len == -1) {
640                 break;
641             }
642 
643             try {
644                 out.write(buffer, 0, len);
645 
646                 mMadeProgress = true;
647                 mInfoDelta.mCurrentBytes += len;
648 
649                 updateProgress(outFd);
650 
651             } catch (IOException e) {
652                 throw new StopRequestException(STATUS_FILE_ERROR, e);
653             }
654         }
655 
656         // Finished without error; verify length if known
657         if (mInfoDelta.mTotalBytes != -1 && mInfoDelta.mCurrentBytes != mInfoDelta.mTotalBytes) {
658             throw new StopRequestException(STATUS_HTTP_DATA_ERROR, "Content length mismatch; found "
659                     + mInfoDelta.mCurrentBytes + " instead of " + mInfoDelta.mTotalBytes);
660         }
661     }
662 
663     /**
664      * Called just before the thread finishes, regardless of status, to take any
665      * necessary action on the downloaded file.
666      */
finalizeDestination()667     private void finalizeDestination() {
668         if (Downloads.Impl.isStatusError(mInfoDelta.mStatus)) {
669             // When error, free up any disk space
670             try {
671                 final ParcelFileDescriptor target = mContext.getContentResolver()
672                         .openFileDescriptor(mInfo.getAllDownloadsUri(), "rw");
673                 try {
674                     Os.ftruncate(target.getFileDescriptor(), 0);
675                 } catch (ErrnoException ignored) {
676                 } finally {
677                     IoUtils.closeQuietly(target);
678                 }
679             } catch (FileNotFoundException ignored) {
680             }
681 
682             // Delete if local file
683             if (mInfoDelta.mFileName != null) {
684                 new File(mInfoDelta.mFileName).delete();
685                 mInfoDelta.mFileName = null;
686             }
687 
688         } else if (Downloads.Impl.isStatusSuccess(mInfoDelta.mStatus)) {
689             // When success, open access if local file
690             if (mInfoDelta.mFileName != null) {
691                 if (mInfo.mDestination != Downloads.Impl.DESTINATION_FILE_URI) {
692                     try {
693                         // Move into final resting place, if needed
694                         final File before = new File(mInfoDelta.mFileName);
695                         final File beforeDir = Helpers.getRunningDestinationDirectory(
696                                 mContext, mInfo.mDestination);
697                         final File afterDir = Helpers.getSuccessDestinationDirectory(
698                                 mContext, mInfo.mDestination);
699                         if (!beforeDir.equals(afterDir)
700                                 && before.getParentFile().equals(beforeDir)) {
701                             final File after = new File(afterDir, before.getName());
702                             if (before.renameTo(after)) {
703                                 mInfoDelta.mFileName = after.getAbsolutePath();
704                             }
705                         }
706                     } catch (IOException ignored) {
707                     }
708                 }
709             }
710         }
711     }
712 
713     /**
714      * Check if current connectivity is valid for this request.
715      */
checkConnectivity()716     private void checkConnectivity() throws StopRequestException {
717         // checking connectivity will apply current policy
718         mPolicyDirty = false;
719 
720         final NetworkInfo info = mSystemFacade.getNetworkInfo(mNetwork, mInfo.mUid, mIgnoreBlocked);
721         final NetworkCapabilities caps = mSystemFacade.getNetworkCapabilities(mNetwork);
722         if (info == null || !info.isConnected()) {
723             throw new StopRequestException(STATUS_WAITING_FOR_NETWORK, "Network is disconnected");
724         }
725         if (!caps.hasCapability(NET_CAPABILITY_NOT_ROAMING)
726                 && !mInfo.isRoamingAllowed()) {
727             throw new StopRequestException(STATUS_WAITING_FOR_NETWORK, "Network is roaming");
728         }
729         if (!caps.hasCapability(NET_CAPABILITY_NOT_METERED)
730                 && !mInfo.isMeteredAllowed(mInfoDelta.mTotalBytes)) {
731             throw new StopRequestException(STATUS_WAITING_FOR_NETWORK, "Network is metered");
732         }
733     }
734 
735     /**
736      * Report download progress through the database if necessary.
737      */
updateProgress(FileDescriptor outFd)738     private void updateProgress(FileDescriptor outFd) throws IOException, StopRequestException {
739         final long now = SystemClock.elapsedRealtime();
740         final long currentBytes = mInfoDelta.mCurrentBytes;
741 
742         final long sampleDelta = now - mSpeedSampleStart;
743         if (sampleDelta > 500) {
744             final long sampleSpeed = ((currentBytes - mSpeedSampleBytes) * 1000)
745                     / sampleDelta;
746 
747             if (mSpeed == 0) {
748                 mSpeed = sampleSpeed;
749             } else {
750                 mSpeed = ((mSpeed * 3) + sampleSpeed) / 4;
751             }
752 
753             // Only notify once we have a full sample window
754             if (mSpeedSampleStart != 0) {
755                 mNotifier.notifyDownloadSpeed(mId, mSpeed);
756             }
757 
758             mSpeedSampleStart = now;
759             mSpeedSampleBytes = currentBytes;
760         }
761 
762         final long bytesDelta = currentBytes - mLastUpdateBytes;
763         final long timeDelta = now - mLastUpdateTime;
764         if (bytesDelta > Constants.MIN_PROGRESS_STEP && timeDelta > Constants.MIN_PROGRESS_TIME) {
765             // fsync() to ensure that current progress has been flushed to disk,
766             // so we can always resume based on latest database information.
767             outFd.sync();
768 
769             mInfoDelta.writeToDatabaseOrThrow();
770 
771             mLastUpdateBytes = currentBytes;
772             mLastUpdateTime = now;
773         }
774     }
775 
776     /**
777      * Process response headers from first server response. This derives its
778      * filename, size, and ETag.
779      */
parseOkHeaders(HttpURLConnection conn)780     private void parseOkHeaders(HttpURLConnection conn) throws StopRequestException {
781         if (mInfoDelta.mFileName == null) {
782             final String contentDisposition = conn.getHeaderField("Content-Disposition");
783             final String contentLocation = conn.getHeaderField("Content-Location");
784 
785             try {
786                 mInfoDelta.mFileName = Helpers.generateSaveFile(mContext, mInfoDelta.mUri,
787                         mInfo.mHint, contentDisposition, contentLocation, mInfoDelta.mMimeType,
788                         mInfo.mDestination);
789             } catch (IOException e) {
790                 throw new StopRequestException(
791                         Downloads.Impl.STATUS_FILE_ERROR, "Failed to generate filename: " + e);
792             }
793         }
794 
795         if (mInfoDelta.mMimeType == null) {
796             mInfoDelta.mMimeType = Intent.normalizeMimeType(conn.getContentType());
797         }
798 
799         final String transferEncoding = conn.getHeaderField("Transfer-Encoding");
800         if (transferEncoding == null) {
801             mInfoDelta.mTotalBytes = getHeaderFieldLong(conn, "Content-Length", -1);
802         } else {
803             mInfoDelta.mTotalBytes = -1;
804         }
805 
806         mInfoDelta.mETag = conn.getHeaderField("ETag");
807 
808         mInfoDelta.writeToDatabaseOrThrow();
809 
810         // Check connectivity again now that we know the total size
811         checkConnectivity();
812     }
813 
parseUnavailableHeaders(HttpURLConnection conn)814     private void parseUnavailableHeaders(HttpURLConnection conn) {
815         long retryAfter = conn.getHeaderFieldInt("Retry-After", -1);
816         retryAfter = MathUtils.constrain(retryAfter, Constants.MIN_RETRY_AFTER,
817                 Constants.MAX_RETRY_AFTER);
818         mInfoDelta.mRetryAfter = (int) (retryAfter * SECOND_IN_MILLIS);
819     }
820 
821     /**
822      * Add custom headers for this download to the HTTP request.
823      */
addRequestHeaders(HttpURLConnection conn, boolean resuming)824     private void addRequestHeaders(HttpURLConnection conn, boolean resuming) {
825         for (Pair<String, String> header : mInfo.getHeaders()) {
826             conn.addRequestProperty(header.first, header.second);
827         }
828 
829         // Only splice in user agent when not already defined
830         if (conn.getRequestProperty("User-Agent") == null) {
831             conn.addRequestProperty("User-Agent", mInfo.getUserAgent());
832         }
833 
834         // Defeat transparent gzip compression, since it doesn't allow us to
835         // easily resume partial downloads.
836         conn.setRequestProperty("Accept-Encoding", "identity");
837 
838         // Defeat connection reuse, since otherwise servers may continue
839         // streaming large downloads after cancelled.
840         conn.setRequestProperty("Connection", "close");
841 
842         if (resuming) {
843             if (mInfoDelta.mETag != null) {
844                 conn.addRequestProperty("If-Match", mInfoDelta.mETag);
845             }
846             conn.addRequestProperty("Range", "bytes=" + mInfoDelta.mCurrentBytes + "-");
847         }
848     }
849 
logDebug(String msg)850     private void logDebug(String msg) {
851         Log.d(TAG, "[" + mId + "] " + msg);
852     }
853 
logWarning(String msg)854     private void logWarning(String msg) {
855         Log.w(TAG, "[" + mId + "] " + msg);
856     }
857 
logError(String msg, Throwable t)858     private void logError(String msg, Throwable t) {
859         Log.e(TAG, "[" + mId + "] " + msg, t);
860     }
861 
862     private INetworkPolicyListener mPolicyListener = new NetworkPolicyManager.Listener() {
863         @Override
864         public void onUidRulesChanged(int uid, int uidRules) {
865             // caller is NPMS, since we only register with them
866             if (uid == mInfo.mUid) {
867                 mPolicyDirty = true;
868             }
869         }
870 
871         @Override
872         public void onMeteredIfacesChanged(String[] meteredIfaces) {
873             // caller is NPMS, since we only register with them
874             mPolicyDirty = true;
875         }
876 
877         @Override
878         public void onRestrictBackgroundChanged(boolean restrictBackground) {
879             // caller is NPMS, since we only register with them
880             mPolicyDirty = true;
881         }
882 
883         @Override
884         public void onUidPoliciesChanged(int uid, int uidPolicies) {
885             // caller is NPMS, since we only register with them
886             if (uid == mInfo.mUid) {
887                 mPolicyDirty = true;
888             }
889         }
890     };
891 
getHeaderFieldLong(URLConnection conn, String field, long defaultValue)892     private static long getHeaderFieldLong(URLConnection conn, String field, long defaultValue) {
893         try {
894             return Long.parseLong(conn.getHeaderField(field));
895         } catch (NumberFormatException e) {
896             return defaultValue;
897         }
898     }
899 
900     /**
901      * Return if given status is eligible to be treated as
902      * {@link android.provider.Downloads.Impl#STATUS_WAITING_TO_RETRY}.
903      */
isStatusRetryable(int status)904     public static boolean isStatusRetryable(int status) {
905         switch (status) {
906             case STATUS_HTTP_DATA_ERROR:
907             case HTTP_UNAVAILABLE:
908             case HTTP_INTERNAL_ERROR:
909             case STATUS_FILE_ERROR:
910                 return true;
911             default:
912                 return false;
913         }
914     }
915 }
916