LocalTransport.java revision 9679410db578e179c7559e7a52bb21c8082e9631
1/* 2 * Copyright (C) 2009 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 17package com.android.internal.backup; 18 19import android.app.backup.BackupDataInput; 20import android.app.backup.BackupDataOutput; 21import android.app.backup.BackupTransport; 22import android.app.backup.RestoreDescription; 23import android.app.backup.RestoreSet; 24import android.content.ComponentName; 25import android.content.Context; 26import android.content.Intent; 27import android.content.pm.PackageInfo; 28import android.os.Environment; 29import android.os.ParcelFileDescriptor; 30import android.os.SELinux; 31import android.system.ErrnoException; 32import android.system.Os; 33import android.system.StructStat; 34import android.util.Log; 35 36import com.android.org.bouncycastle.util.encoders.Base64; 37 38import java.io.BufferedOutputStream; 39import java.io.File; 40import java.io.FileInputStream; 41import java.io.FileNotFoundException; 42import java.io.FileOutputStream; 43import java.io.IOException; 44import java.util.ArrayList; 45import java.util.Arrays; 46import java.util.Collections; 47import java.util.HashSet; 48import java.util.List; 49 50import static android.system.OsConstants.*; 51 52/** 53 * Backup transport for stashing stuff into a known location on disk, and 54 * later restoring from there. For testing only. 55 */ 56 57public class LocalTransport extends BackupTransport { 58 private static final String TAG = "LocalTransport"; 59 private static final boolean DEBUG = false; 60 61 private static final String TRANSPORT_DIR_NAME 62 = "com.android.internal.backup.LocalTransport"; 63 64 private static final String TRANSPORT_DESTINATION_STRING 65 = "Backing up to debug-only private cache"; 66 67 private static final String TRANSPORT_DATA_MANAGEMENT_LABEL 68 = ""; 69 70 private static final String INCREMENTAL_DIR = "_delta"; 71 private static final String FULL_DATA_DIR = "_full"; 72 73 // The currently-active restore set always has the same (nonzero!) token 74 private static final long CURRENT_SET_TOKEN = 1; 75 76 private Context mContext; 77 private File mDataDir = new File(Environment.getDownloadCacheDirectory(), "backup"); 78 private File mCurrentSetDir = new File(mDataDir, Long.toString(CURRENT_SET_TOKEN)); 79 private File mCurrentSetIncrementalDir = new File(mCurrentSetDir, INCREMENTAL_DIR); 80 private File mCurrentSetFullDir = new File(mCurrentSetDir, FULL_DATA_DIR); 81 82 private PackageInfo[] mRestorePackages = null; 83 private int mRestorePackage = -1; // Index into mRestorePackages 84 private int mRestoreType; 85 private File mRestoreSetDir; 86 private File mRestoreSetIncrementalDir; 87 private File mRestoreSetFullDir; 88 private long mRestoreToken; 89 90 // Additional bookkeeping for full backup 91 private String mFullTargetPackage; 92 private ParcelFileDescriptor mSocket; 93 private FileInputStream mSocketInputStream; 94 private BufferedOutputStream mFullBackupOutputStream; 95 private byte[] mFullBackupBuffer; 96 97 private File mFullRestoreSetDir; 98 private HashSet<String> mFullRestorePackages; 99 private FileInputStream mCurFullRestoreStream; 100 private FileOutputStream mFullRestoreSocketStream; 101 private byte[] mFullRestoreBuffer; 102 103 public LocalTransport(Context context) { 104 mContext = context; 105 mCurrentSetDir.mkdirs(); 106 mCurrentSetFullDir.mkdir(); 107 mCurrentSetIncrementalDir.mkdir(); 108 if (!SELinux.restorecon(mCurrentSetDir)) { 109 Log.e(TAG, "SELinux restorecon failed for " + mCurrentSetDir); 110 } 111 } 112 113 @Override 114 public String name() { 115 return new ComponentName(mContext, this.getClass()).flattenToShortString(); 116 } 117 118 @Override 119 public Intent configurationIntent() { 120 // The local transport is not user-configurable 121 return null; 122 } 123 124 @Override 125 public String currentDestinationString() { 126 return TRANSPORT_DESTINATION_STRING; 127 } 128 129 public Intent dataManagementIntent() { 130 // The local transport does not present a data-management UI 131 // TODO: consider adding simple UI to wipe the archives entirely, 132 // for cleaning up the cache partition. 133 return null; 134 } 135 136 public String dataManagementLabel() { 137 return TRANSPORT_DATA_MANAGEMENT_LABEL; 138 } 139 140 @Override 141 public String transportDirName() { 142 return TRANSPORT_DIR_NAME; 143 } 144 145 @Override 146 public long requestBackupTime() { 147 // any time is a good time for local backup 148 return 0; 149 } 150 151 @Override 152 public int initializeDevice() { 153 if (DEBUG) Log.v(TAG, "wiping all data"); 154 deleteContents(mCurrentSetDir); 155 return TRANSPORT_OK; 156 } 157 158 @Override 159 public int performBackup(PackageInfo packageInfo, ParcelFileDescriptor data) { 160 if (DEBUG) { 161 try { 162 StructStat ss = Os.fstat(data.getFileDescriptor()); 163 Log.v(TAG, "performBackup() pkg=" + packageInfo.packageName 164 + " size=" + ss.st_size); 165 } catch (ErrnoException e) { 166 Log.w(TAG, "Unable to stat input file in performBackup() on " 167 + packageInfo.packageName); 168 } 169 } 170 171 File packageDir = new File(mCurrentSetIncrementalDir, packageInfo.packageName); 172 packageDir.mkdirs(); 173 174 // Each 'record' in the restore set is kept in its own file, named by 175 // the record key. Wind through the data file, extracting individual 176 // record operations and building a set of all the updates to apply 177 // in this update. 178 BackupDataInput changeSet = new BackupDataInput(data.getFileDescriptor()); 179 try { 180 int bufSize = 512; 181 byte[] buf = new byte[bufSize]; 182 while (changeSet.readNextHeader()) { 183 String key = changeSet.getKey(); 184 String base64Key = new String(Base64.encode(key.getBytes())); 185 File entityFile = new File(packageDir, base64Key); 186 187 int dataSize = changeSet.getDataSize(); 188 189 if (DEBUG) Log.v(TAG, "Got change set key=" + key + " size=" + dataSize 190 + " key64=" + base64Key); 191 192 if (dataSize >= 0) { 193 if (entityFile.exists()) { 194 entityFile.delete(); 195 } 196 FileOutputStream entity = new FileOutputStream(entityFile); 197 198 if (dataSize > bufSize) { 199 bufSize = dataSize; 200 buf = new byte[bufSize]; 201 } 202 changeSet.readEntityData(buf, 0, dataSize); 203 if (DEBUG) { 204 try { 205 long cur = Os.lseek(data.getFileDescriptor(), 0, SEEK_CUR); 206 Log.v(TAG, " read entity data; new pos=" + cur); 207 } 208 catch (ErrnoException e) { 209 Log.w(TAG, "Unable to stat input file in performBackup() on " 210 + packageInfo.packageName); 211 } 212 } 213 214 try { 215 entity.write(buf, 0, dataSize); 216 } catch (IOException e) { 217 Log.e(TAG, "Unable to update key file " + entityFile.getAbsolutePath()); 218 return TRANSPORT_ERROR; 219 } finally { 220 entity.close(); 221 } 222 } else { 223 entityFile.delete(); 224 } 225 } 226 return TRANSPORT_OK; 227 } catch (IOException e) { 228 // oops, something went wrong. abort the operation and return error. 229 Log.v(TAG, "Exception reading backup input:", e); 230 return TRANSPORT_ERROR; 231 } 232 } 233 234 // Deletes the contents but not the given directory 235 private void deleteContents(File dirname) { 236 File[] contents = dirname.listFiles(); 237 if (contents != null) { 238 for (File f : contents) { 239 if (f.isDirectory()) { 240 // delete the directory's contents then fall through 241 // and delete the directory itself. 242 deleteContents(f); 243 } 244 f.delete(); 245 } 246 } 247 } 248 249 @Override 250 public int clearBackupData(PackageInfo packageInfo) { 251 if (DEBUG) Log.v(TAG, "clearBackupData() pkg=" + packageInfo.packageName); 252 253 File packageDir = new File(mCurrentSetIncrementalDir, packageInfo.packageName); 254 final File[] fileset = packageDir.listFiles(); 255 if (fileset != null) { 256 for (File f : fileset) { 257 f.delete(); 258 } 259 packageDir.delete(); 260 } 261 262 packageDir = new File(mCurrentSetFullDir, packageInfo.packageName); 263 final File[] tarballs = packageDir.listFiles(); 264 if (tarballs != null) { 265 for (File f : tarballs) { 266 f.delete(); 267 } 268 packageDir.delete(); 269 } 270 271 return TRANSPORT_OK; 272 } 273 274 @Override 275 public int finishBackup() { 276 if (DEBUG) Log.v(TAG, "finishBackup()"); 277 if (mSocket != null) { 278 if (DEBUG) { 279 Log.v(TAG, "Concluding full backup of " + mFullTargetPackage); 280 } 281 try { 282 mFullBackupOutputStream.flush(); 283 mFullBackupOutputStream.close(); 284 mSocketInputStream = null; 285 mFullTargetPackage = null; 286 mSocket.close(); 287 } catch (IOException e) { 288 if (DEBUG) { 289 Log.w(TAG, "Exception caught in finishBackup()", e); 290 } 291 return TRANSPORT_ERROR; 292 } finally { 293 mSocket = null; 294 } 295 } 296 return TRANSPORT_OK; 297 } 298 299 // ------------------------------------------------------------------------------------ 300 // Full backup handling 301 302 @Override 303 public long requestFullBackupTime() { 304 return 0; 305 } 306 307 @Override 308 public int performFullBackup(PackageInfo targetPackage, ParcelFileDescriptor socket) { 309 if (mSocket != null) { 310 Log.e(TAG, "Attempt to initiate full backup while one is in progress"); 311 return TRANSPORT_ERROR; 312 } 313 314 if (DEBUG) { 315 Log.i(TAG, "performFullBackup : " + targetPackage); 316 } 317 318 // We know a priori that we run in the system process, so we need to make 319 // sure to dup() our own copy of the socket fd. Transports which run in 320 // their own processes must not do this. 321 try { 322 mSocket = ParcelFileDescriptor.dup(socket.getFileDescriptor()); 323 mSocketInputStream = new FileInputStream(mSocket.getFileDescriptor()); 324 } catch (IOException e) { 325 Log.e(TAG, "Unable to process socket for full backup"); 326 return TRANSPORT_ERROR; 327 } 328 329 mFullTargetPackage = targetPackage.packageName; 330 FileOutputStream tarstream; 331 try { 332 File tarball = new File(mCurrentSetFullDir, mFullTargetPackage); 333 tarstream = new FileOutputStream(tarball); 334 } catch (FileNotFoundException e) { 335 return TRANSPORT_ERROR; 336 } 337 mFullBackupOutputStream = new BufferedOutputStream(tarstream); 338 mFullBackupBuffer = new byte[4096]; 339 340 return TRANSPORT_OK; 341 } 342 343 @Override 344 public int sendBackupData(int numBytes) { 345 if (mFullBackupBuffer == null) { 346 Log.w(TAG, "Attempted sendBackupData before performFullBackup"); 347 return TRANSPORT_ERROR; 348 } 349 350 if (numBytes > mFullBackupBuffer.length) { 351 mFullBackupBuffer = new byte[numBytes]; 352 } 353 while (numBytes > 0) { 354 try { 355 int nRead = mSocketInputStream.read(mFullBackupBuffer, 0, numBytes); 356 if (nRead < 0) { 357 // Something went wrong if we expect data but saw EOD 358 Log.w(TAG, "Unexpected EOD; failing backup"); 359 return TRANSPORT_ERROR; 360 } 361 mFullBackupOutputStream.write(mFullBackupBuffer, 0, nRead); 362 numBytes -= nRead; 363 } catch (IOException e) { 364 Log.e(TAG, "Error handling backup data for " + mFullTargetPackage); 365 return TRANSPORT_ERROR; 366 } 367 } 368 return TRANSPORT_OK; 369 } 370 371 // ------------------------------------------------------------------------------------ 372 // Restore handling 373 static final long[] POSSIBLE_SETS = { 2, 3, 4, 5, 6, 7, 8, 9 }; 374 375 @Override 376 public RestoreSet[] getAvailableRestoreSets() { 377 long[] existing = new long[POSSIBLE_SETS.length + 1]; 378 int num = 0; 379 380 // see which possible non-current sets exist... 381 for (long token : POSSIBLE_SETS) { 382 if ((new File(mDataDir, Long.toString(token))).exists()) { 383 existing[num++] = token; 384 } 385 } 386 // ...and always the currently-active set last 387 existing[num++] = CURRENT_SET_TOKEN; 388 389 RestoreSet[] available = new RestoreSet[num]; 390 for (int i = 0; i < available.length; i++) { 391 available[i] = new RestoreSet("Local disk image", "flash", existing[i]); 392 } 393 return available; 394 } 395 396 @Override 397 public long getCurrentRestoreSet() { 398 // The current restore set always has the same token 399 return CURRENT_SET_TOKEN; 400 } 401 402 @Override 403 public int startRestore(long token, PackageInfo[] packages) { 404 if (DEBUG) Log.v(TAG, "start restore " + token + " : " + packages.length 405 + " matching packages"); 406 mRestorePackages = packages; 407 mRestorePackage = -1; 408 mRestoreToken = token; 409 mRestoreSetDir = new File(mDataDir, Long.toString(token)); 410 mRestoreSetIncrementalDir = new File(mRestoreSetDir, INCREMENTAL_DIR); 411 mRestoreSetFullDir = new File(mRestoreSetDir, FULL_DATA_DIR); 412 return TRANSPORT_OK; 413 } 414 415 @Override 416 public RestoreDescription nextRestorePackage() { 417 if (mRestorePackages == null) throw new IllegalStateException("startRestore not called"); 418 419 boolean found = false; 420 while (++mRestorePackage < mRestorePackages.length) { 421 String name = mRestorePackages[mRestorePackage].packageName; 422 423 // If we have key/value data for this package, deliver that 424 // skip packages where we have a data dir but no actual contents 425 String[] contents = (new File(mRestoreSetIncrementalDir, name)).list(); 426 if (contents != null && contents.length > 0) { 427 if (DEBUG) Log.v(TAG, " nextRestorePackage(TYPE_KEY_VALUE) = " + name); 428 mRestoreType = RestoreDescription.TYPE_KEY_VALUE; 429 found = true; 430 } 431 432 if (!found) { 433 // No key/value data; check for [non-empty] full data 434 File maybeFullData = new File(mRestoreSetFullDir, name); 435 if (maybeFullData.length() > 0) { 436 if (DEBUG) Log.v(TAG, " nextRestorePackage(TYPE_FULL_STREAM) = " + name); 437 mRestoreType = RestoreDescription.TYPE_FULL_STREAM; 438 mCurFullRestoreStream = null; // ensure starting from the ground state 439 found = true; 440 } 441 } 442 443 if (found) { 444 return new RestoreDescription(name, mRestoreType); 445 } 446 } 447 448 if (DEBUG) Log.v(TAG, " no more packages to restore"); 449 return RestoreDescription.NO_MORE_PACKAGES; 450 } 451 452 @Override 453 public int getRestoreData(ParcelFileDescriptor outFd) { 454 if (mRestorePackages == null) throw new IllegalStateException("startRestore not called"); 455 if (mRestorePackage < 0) throw new IllegalStateException("nextRestorePackage not called"); 456 if (mRestoreType != RestoreDescription.TYPE_KEY_VALUE) { 457 throw new IllegalStateException("getRestoreData(fd) for non-key/value dataset"); 458 } 459 File packageDir = new File(mRestoreSetIncrementalDir, 460 mRestorePackages[mRestorePackage].packageName); 461 462 // The restore set is the concatenation of the individual record blobs, 463 // each of which is a file in the package's directory. We return the 464 // data in lexical order sorted by key, so that apps which use synthetic 465 // keys like BLOB_1, BLOB_2, etc will see the date in the most obvious 466 // order. 467 ArrayList<DecodedFilename> blobs = contentsByKey(packageDir); 468 if (blobs == null) { // nextRestorePackage() ensures the dir exists, so this is an error 469 Log.e(TAG, "No keys for package: " + packageDir); 470 return TRANSPORT_ERROR; 471 } 472 473 // We expect at least some data if the directory exists in the first place 474 if (DEBUG) Log.v(TAG, " getRestoreData() found " + blobs.size() + " key files"); 475 BackupDataOutput out = new BackupDataOutput(outFd.getFileDescriptor()); 476 try { 477 for (DecodedFilename keyEntry : blobs) { 478 File f = keyEntry.file; 479 FileInputStream in = new FileInputStream(f); 480 try { 481 int size = (int) f.length(); 482 byte[] buf = new byte[size]; 483 in.read(buf); 484 if (DEBUG) Log.v(TAG, " ... key=" + keyEntry.key + " size=" + size); 485 out.writeEntityHeader(keyEntry.key, size); 486 out.writeEntityData(buf, size); 487 } finally { 488 in.close(); 489 } 490 } 491 return TRANSPORT_OK; 492 } catch (IOException e) { 493 Log.e(TAG, "Unable to read backup records", e); 494 return TRANSPORT_ERROR; 495 } 496 } 497 498 static class DecodedFilename implements Comparable<DecodedFilename> { 499 public File file; 500 public String key; 501 502 public DecodedFilename(File f) { 503 file = f; 504 key = new String(Base64.decode(f.getName())); 505 } 506 507 @Override 508 public int compareTo(DecodedFilename other) { 509 // sorts into ascending lexical order by decoded key 510 return key.compareTo(other.key); 511 } 512 } 513 514 // Return a list of the files in the given directory, sorted lexically by 515 // the Base64-decoded file name, not by the on-disk filename 516 private ArrayList<DecodedFilename> contentsByKey(File dir) { 517 File[] allFiles = dir.listFiles(); 518 if (allFiles == null || allFiles.length == 0) { 519 return null; 520 } 521 522 // Decode the filenames into keys then sort lexically by key 523 ArrayList<DecodedFilename> contents = new ArrayList<DecodedFilename>(); 524 for (File f : allFiles) { 525 contents.add(new DecodedFilename(f)); 526 } 527 Collections.sort(contents); 528 return contents; 529 } 530 531 @Override 532 public void finishRestore() { 533 if (DEBUG) Log.v(TAG, "finishRestore()"); 534 if (mRestoreType == RestoreDescription.TYPE_FULL_STREAM) { 535 resetFullRestoreState(); 536 } 537 mRestoreType = 0; 538 } 539 540 // ------------------------------------------------------------------------------------ 541 // Full restore handling 542 543 private void resetFullRestoreState() { 544 try { 545 mCurFullRestoreStream.close(); 546 } catch (IOException e) { 547 Log.w(TAG, "Unable to close full restore input stream"); 548 } 549 mCurFullRestoreStream = null; 550 mFullRestoreSocketStream = null; 551 mFullRestoreBuffer = null; 552 } 553 554 /** 555 * Ask the transport to provide data for the "current" package being restored. The 556 * transport then writes some data to the socket supplied to this call, and returns 557 * the number of bytes written. The system will then read that many bytes and 558 * stream them to the application's agent for restore, then will call this method again 559 * to receive the next chunk of the archive. This sequence will be repeated until the 560 * transport returns zero indicating that all of the package's data has been delivered 561 * (or returns a negative value indicating some sort of hard error condition at the 562 * transport level). 563 * 564 * <p>After this method returns zero, the system will then call 565 * {@link #getNextFullRestorePackage()} to begin the restore process for the next 566 * application, and the sequence begins again. 567 * 568 * @param socket The file descriptor that the transport will use for delivering the 569 * streamed archive. 570 * @return 0 when no more data for the current package is available. A positive value 571 * indicates the presence of that much data to be delivered to the app. A negative 572 * return value is treated as equivalent to {@link BackupTransport#TRANSPORT_ERROR}, 573 * indicating a fatal error condition that precludes further restore operations 574 * on the current dataset. 575 */ 576 @Override 577 public int getNextFullRestoreDataChunk(ParcelFileDescriptor socket) { 578 if (mRestoreType != RestoreDescription.TYPE_FULL_STREAM) { 579 throw new IllegalStateException("Asked for full restore data for non-stream package"); 580 } 581 582 // first chunk? 583 if (mCurFullRestoreStream == null) { 584 final String name = mRestorePackages[mRestorePackage].packageName; 585 if (DEBUG) Log.i(TAG, "Starting full restore of " + name); 586 File dataset = new File(mRestoreSetFullDir, name); 587 try { 588 mCurFullRestoreStream = new FileInputStream(dataset); 589 } catch (IOException e) { 590 // If we can't open the target package's tarball, we return the single-package 591 // error code and let the caller go on to the next package. 592 Log.e(TAG, "Unable to read archive for " + name); 593 return TRANSPORT_PACKAGE_REJECTED; 594 } 595 mFullRestoreSocketStream = new FileOutputStream(socket.getFileDescriptor()); 596 mFullRestoreBuffer = new byte[2*1024]; 597 } 598 599 int nRead; 600 try { 601 nRead = mCurFullRestoreStream.read(mFullRestoreBuffer); 602 if (nRead < 0) { 603 // EOF: tell the caller we're done 604 nRead = NO_MORE_DATA; 605 } else if (nRead == 0) { 606 // This shouldn't happen when reading a FileInputStream; we should always 607 // get either a positive nonzero byte count or -1. Log the situation and 608 // treat it as EOF. 609 Log.w(TAG, "read() of archive file returned 0; treating as EOF"); 610 nRead = NO_MORE_DATA; 611 } else { 612 if (DEBUG) { 613 Log.i(TAG, " delivering restore chunk: " + nRead); 614 } 615 mFullRestoreSocketStream.write(mFullRestoreBuffer, 0, nRead); 616 } 617 } catch (IOException e) { 618 return TRANSPORT_ERROR; // Hard error accessing the file; shouldn't happen 619 } finally { 620 // Most transports will need to explicitly close 'socket' here, but this transport 621 // is in the same process as the caller so it can leave it up to the backup manager 622 // to manage both socket fds. 623 } 624 625 return nRead; 626 } 627 628 /** 629 * If the OS encounters an error while processing {@link RestoreDescription#TYPE_FULL_STREAM} 630 * data for restore, it will invoke this method to tell the transport that it should 631 * abandon the data download for the current package. The OS will then either call 632 * {@link #nextRestorePackage()} again to move on to restoring the next package in the 633 * set being iterated over, or will call {@link #finishRestore()} to shut down the restore 634 * operation. 635 * 636 * @return {@link #TRANSPORT_OK} if the transport was successful in shutting down the 637 * current stream cleanly, or {@link #TRANSPORT_ERROR} to indicate a serious 638 * transport-level failure. If the transport reports an error here, the entire restore 639 * operation will immediately be finished with no further attempts to restore app data. 640 */ 641 @Override 642 public int abortFullRestore() { 643 if (mRestoreType != RestoreDescription.TYPE_FULL_STREAM) { 644 throw new IllegalStateException("abortFullRestore() but not currently restoring"); 645 } 646 resetFullRestoreState(); 647 mRestoreType = 0; 648 return TRANSPORT_OK; 649 } 650 651} 652