LocalTransport.java revision 5a009f9008d1f18b156c142b69e173109f5e218b
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 = true; 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 INCREMENTAL_DIR = "_delta"; 68 private static final String FULL_DATA_DIR = "_full"; 69 70 // The currently-active restore set always has the same (nonzero!) token 71 private static final long CURRENT_SET_TOKEN = 1; 72 73 private Context mContext; 74 private File mDataDir = new File(Environment.getDownloadCacheDirectory(), "backup"); 75 private File mCurrentSetDir = new File(mDataDir, Long.toString(CURRENT_SET_TOKEN)); 76 private File mCurrentSetIncrementalDir = new File(mCurrentSetDir, INCREMENTAL_DIR); 77 private File mCurrentSetFullDir = new File(mCurrentSetDir, FULL_DATA_DIR); 78 79 private PackageInfo[] mRestorePackages = null; 80 private int mRestorePackage = -1; // Index into mRestorePackages 81 private int mRestoreType; 82 private File mRestoreSetDir; 83 private File mRestoreSetIncrementalDir; 84 private File mRestoreSetFullDir; 85 private long mRestoreToken; 86 87 // Additional bookkeeping for full backup 88 private String mFullTargetPackage; 89 private ParcelFileDescriptor mSocket; 90 private FileInputStream mSocketInputStream; 91 private BufferedOutputStream mFullBackupOutputStream; 92 private byte[] mFullBackupBuffer; 93 94 private File mFullRestoreSetDir; 95 private HashSet<String> mFullRestorePackages; 96 private FileInputStream mCurFullRestoreStream; 97 private FileOutputStream mFullRestoreSocketStream; 98 private byte[] mFullRestoreBuffer; 99 100 public LocalTransport(Context context) { 101 mContext = context; 102 mCurrentSetDir.mkdirs(); 103 mCurrentSetFullDir.mkdir(); 104 mCurrentSetIncrementalDir.mkdir(); 105 if (!SELinux.restorecon(mCurrentSetDir)) { 106 Log.e(TAG, "SELinux restorecon failed for " + mCurrentSetDir); 107 } 108 } 109 110 @Override 111 public String name() { 112 return new ComponentName(mContext, this.getClass()).flattenToShortString(); 113 } 114 115 @Override 116 public Intent configurationIntent() { 117 // The local transport is not user-configurable 118 return null; 119 } 120 121 @Override 122 public String currentDestinationString() { 123 return TRANSPORT_DESTINATION_STRING; 124 } 125 126 @Override 127 public String transportDirName() { 128 return TRANSPORT_DIR_NAME; 129 } 130 131 @Override 132 public long requestBackupTime() { 133 // any time is a good time for local backup 134 return 0; 135 } 136 137 @Override 138 public int initializeDevice() { 139 if (DEBUG) Log.v(TAG, "wiping all data"); 140 deleteContents(mCurrentSetDir); 141 return TRANSPORT_OK; 142 } 143 144 @Override 145 public int performBackup(PackageInfo packageInfo, ParcelFileDescriptor data) { 146 if (DEBUG) { 147 try { 148 StructStat ss = Os.fstat(data.getFileDescriptor()); 149 Log.v(TAG, "performBackup() pkg=" + packageInfo.packageName 150 + " size=" + ss.st_size); 151 } catch (ErrnoException e) { 152 Log.w(TAG, "Unable to stat input file in performBackup() on " 153 + packageInfo.packageName); 154 } 155 } 156 157 File packageDir = new File(mCurrentSetIncrementalDir, packageInfo.packageName); 158 packageDir.mkdirs(); 159 160 // Each 'record' in the restore set is kept in its own file, named by 161 // the record key. Wind through the data file, extracting individual 162 // record operations and building a set of all the updates to apply 163 // in this update. 164 BackupDataInput changeSet = new BackupDataInput(data.getFileDescriptor()); 165 try { 166 int bufSize = 512; 167 byte[] buf = new byte[bufSize]; 168 while (changeSet.readNextHeader()) { 169 String key = changeSet.getKey(); 170 String base64Key = new String(Base64.encode(key.getBytes())); 171 File entityFile = new File(packageDir, base64Key); 172 173 int dataSize = changeSet.getDataSize(); 174 175 if (DEBUG) Log.v(TAG, "Got change set key=" + key + " size=" + dataSize 176 + " key64=" + base64Key); 177 178 if (dataSize >= 0) { 179 if (entityFile.exists()) { 180 entityFile.delete(); 181 } 182 FileOutputStream entity = new FileOutputStream(entityFile); 183 184 if (dataSize > bufSize) { 185 bufSize = dataSize; 186 buf = new byte[bufSize]; 187 } 188 changeSet.readEntityData(buf, 0, dataSize); 189 if (DEBUG) { 190 try { 191 long cur = Os.lseek(data.getFileDescriptor(), 0, SEEK_CUR); 192 Log.v(TAG, " read entity data; new pos=" + cur); 193 } 194 catch (ErrnoException e) { 195 Log.w(TAG, "Unable to stat input file in performBackup() on " 196 + packageInfo.packageName); 197 } 198 } 199 200 try { 201 entity.write(buf, 0, dataSize); 202 } catch (IOException e) { 203 Log.e(TAG, "Unable to update key file " + entityFile.getAbsolutePath()); 204 return TRANSPORT_ERROR; 205 } finally { 206 entity.close(); 207 } 208 } else { 209 entityFile.delete(); 210 } 211 } 212 return TRANSPORT_OK; 213 } catch (IOException e) { 214 // oops, something went wrong. abort the operation and return error. 215 Log.v(TAG, "Exception reading backup input:", e); 216 return TRANSPORT_ERROR; 217 } 218 } 219 220 // Deletes the contents but not the given directory 221 private void deleteContents(File dirname) { 222 File[] contents = dirname.listFiles(); 223 if (contents != null) { 224 for (File f : contents) { 225 if (f.isDirectory()) { 226 // delete the directory's contents then fall through 227 // and delete the directory itself. 228 deleteContents(f); 229 } 230 f.delete(); 231 } 232 } 233 } 234 235 @Override 236 public int clearBackupData(PackageInfo packageInfo) { 237 if (DEBUG) Log.v(TAG, "clearBackupData() pkg=" + packageInfo.packageName); 238 239 File packageDir = new File(mCurrentSetIncrementalDir, packageInfo.packageName); 240 final File[] fileset = packageDir.listFiles(); 241 if (fileset != null) { 242 for (File f : fileset) { 243 f.delete(); 244 } 245 packageDir.delete(); 246 } 247 248 packageDir = new File(mCurrentSetFullDir, packageInfo.packageName); 249 final File[] tarballs = packageDir.listFiles(); 250 if (tarballs != null) { 251 for (File f : tarballs) { 252 f.delete(); 253 } 254 packageDir.delete(); 255 } 256 257 return TRANSPORT_OK; 258 } 259 260 @Override 261 public int finishBackup() { 262 if (DEBUG) Log.v(TAG, "finishBackup()"); 263 if (mSocket != null) { 264 if (DEBUG) { 265 Log.v(TAG, "Concluding full backup of " + mFullTargetPackage); 266 } 267 try { 268 mFullBackupOutputStream.flush(); 269 mFullBackupOutputStream.close(); 270 mSocketInputStream = null; 271 mFullTargetPackage = null; 272 mSocket.close(); 273 } catch (IOException e) { 274 return TRANSPORT_ERROR; 275 } finally { 276 mSocket = null; 277 } 278 } 279 return TRANSPORT_OK; 280 } 281 282 // ------------------------------------------------------------------------------------ 283 // Full backup handling 284 285 @Override 286 public long requestFullBackupTime() { 287 return 0; 288 } 289 290 @Override 291 public int performFullBackup(PackageInfo targetPackage, ParcelFileDescriptor socket) { 292 if (mSocket != null) { 293 Log.e(TAG, "Attempt to initiate full backup while one is in progress"); 294 return TRANSPORT_ERROR; 295 } 296 297 if (DEBUG) { 298 Log.i(TAG, "performFullBackup : " + targetPackage); 299 } 300 301 // We know a priori that we run in the system process, so we need to make 302 // sure to dup() our own copy of the socket fd. Transports which run in 303 // their own processes must not do this. 304 try { 305 mSocket = ParcelFileDescriptor.dup(socket.getFileDescriptor()); 306 mSocketInputStream = new FileInputStream(mSocket.getFileDescriptor()); 307 } catch (IOException e) { 308 Log.e(TAG, "Unable to process socket for full backup"); 309 return TRANSPORT_ERROR; 310 } 311 312 mFullTargetPackage = targetPackage.packageName; 313 FileOutputStream tarstream; 314 try { 315 File tarball = new File(mCurrentSetFullDir, mFullTargetPackage); 316 tarstream = new FileOutputStream(tarball); 317 } catch (FileNotFoundException e) { 318 return TRANSPORT_ERROR; 319 } 320 mFullBackupOutputStream = new BufferedOutputStream(tarstream); 321 mFullBackupBuffer = new byte[4096]; 322 323 return TRANSPORT_OK; 324 } 325 326 @Override 327 public int sendBackupData(int numBytes) { 328 if (mFullBackupBuffer == null) { 329 Log.w(TAG, "Attempted sendBackupData before performFullBackup"); 330 return TRANSPORT_ERROR; 331 } 332 333 if (numBytes > mFullBackupBuffer.length) { 334 mFullBackupBuffer = new byte[numBytes]; 335 } 336 while (numBytes > 0) { 337 try { 338 int nRead = mSocketInputStream.read(mFullBackupBuffer, 0, numBytes); 339 if (nRead < 0) { 340 // Something went wrong if we expect data but saw EOD 341 Log.w(TAG, "Unexpected EOD; failing backup"); 342 return TRANSPORT_ERROR; 343 } 344 mFullBackupOutputStream.write(mFullBackupBuffer, 0, nRead); 345 numBytes -= nRead; 346 } catch (IOException e) { 347 Log.e(TAG, "Error handling backup data for " + mFullTargetPackage); 348 return TRANSPORT_ERROR; 349 } 350 } 351 return TRANSPORT_OK; 352 } 353 354 // ------------------------------------------------------------------------------------ 355 // Restore handling 356 static final long[] POSSIBLE_SETS = { 2, 3, 4, 5, 6, 7, 8, 9 }; 357 358 @Override 359 public RestoreSet[] getAvailableRestoreSets() { 360 long[] existing = new long[POSSIBLE_SETS.length + 1]; 361 int num = 0; 362 363 // see which possible non-current sets exist... 364 for (long token : POSSIBLE_SETS) { 365 if ((new File(mDataDir, Long.toString(token))).exists()) { 366 existing[num++] = token; 367 } 368 } 369 // ...and always the currently-active set last 370 existing[num++] = CURRENT_SET_TOKEN; 371 372 RestoreSet[] available = new RestoreSet[num]; 373 for (int i = 0; i < available.length; i++) { 374 available[i] = new RestoreSet("Local disk image", "flash", existing[i]); 375 } 376 return available; 377 } 378 379 @Override 380 public long getCurrentRestoreSet() { 381 // The current restore set always has the same token 382 return CURRENT_SET_TOKEN; 383 } 384 385 @Override 386 public int startRestore(long token, PackageInfo[] packages) { 387 if (DEBUG) Log.v(TAG, "start restore " + token); 388 mRestorePackages = packages; 389 mRestorePackage = -1; 390 mRestoreToken = token; 391 mRestoreSetDir = new File(mDataDir, Long.toString(token)); 392 mRestoreSetIncrementalDir = new File(mRestoreSetDir, INCREMENTAL_DIR); 393 mRestoreSetFullDir = new File(mRestoreSetDir, FULL_DATA_DIR); 394 return TRANSPORT_OK; 395 } 396 397 @Override 398 public RestoreDescription nextRestorePackage() { 399 if (mRestorePackages == null) throw new IllegalStateException("startRestore not called"); 400 401 boolean found = false; 402 while (++mRestorePackage < mRestorePackages.length) { 403 String name = mRestorePackages[mRestorePackage].packageName; 404 405 // If we have key/value data for this package, deliver that 406 // skip packages where we have a data dir but no actual contents 407 String[] contents = (new File(mRestoreSetIncrementalDir, name)).list(); 408 if (contents != null && contents.length > 0) { 409 if (DEBUG) Log.v(TAG, " nextRestorePackage(TYPE_KEY_VALUE) = " + name); 410 mRestoreType = RestoreDescription.TYPE_KEY_VALUE; 411 found = true; 412 } 413 414 if (!found) { 415 // No key/value data; check for [non-empty] full data 416 File maybeFullData = new File(mRestoreSetFullDir, name); 417 if (maybeFullData.length() > 0) { 418 if (DEBUG) Log.v(TAG, " nextRestorePackage(TYPE_FULL_STREAM) = " + name); 419 mRestoreType = RestoreDescription.TYPE_FULL_STREAM; 420 mCurFullRestoreStream = null; // ensure starting from the ground state 421 found = true; 422 } 423 } 424 425 if (found) { 426 return new RestoreDescription(name, mRestoreType); 427 } 428 } 429 430 if (DEBUG) Log.v(TAG, " no more packages to restore"); 431 return RestoreDescription.NO_MORE_PACKAGES; 432 } 433 434 @Override 435 public int getRestoreData(ParcelFileDescriptor outFd) { 436 if (mRestorePackages == null) throw new IllegalStateException("startRestore not called"); 437 if (mRestorePackage < 0) throw new IllegalStateException("nextRestorePackage not called"); 438 if (mRestoreType != RestoreDescription.TYPE_KEY_VALUE) { 439 throw new IllegalStateException("getRestoreData(fd) for non-key/value dataset"); 440 } 441 File packageDir = new File(mRestoreSetDir, mRestorePackages[mRestorePackage].packageName); 442 443 // The restore set is the concatenation of the individual record blobs, 444 // each of which is a file in the package's directory. We return the 445 // data in lexical order sorted by key, so that apps which use synthetic 446 // keys like BLOB_1, BLOB_2, etc will see the date in the most obvious 447 // order. 448 ArrayList<DecodedFilename> blobs = contentsByKey(packageDir); 449 if (blobs == null) { // nextRestorePackage() ensures the dir exists, so this is an error 450 Log.e(TAG, "No keys for package: " + packageDir); 451 return TRANSPORT_ERROR; 452 } 453 454 // We expect at least some data if the directory exists in the first place 455 if (DEBUG) Log.v(TAG, " getRestoreData() found " + blobs.size() + " key files"); 456 BackupDataOutput out = new BackupDataOutput(outFd.getFileDescriptor()); 457 try { 458 for (DecodedFilename keyEntry : blobs) { 459 File f = keyEntry.file; 460 FileInputStream in = new FileInputStream(f); 461 try { 462 int size = (int) f.length(); 463 byte[] buf = new byte[size]; 464 in.read(buf); 465 if (DEBUG) Log.v(TAG, " ... key=" + keyEntry.key + " size=" + size); 466 out.writeEntityHeader(keyEntry.key, size); 467 out.writeEntityData(buf, size); 468 } finally { 469 in.close(); 470 } 471 } 472 return TRANSPORT_OK; 473 } catch (IOException e) { 474 Log.e(TAG, "Unable to read backup records", e); 475 return TRANSPORT_ERROR; 476 } 477 } 478 479 static class DecodedFilename implements Comparable<DecodedFilename> { 480 public File file; 481 public String key; 482 483 public DecodedFilename(File f) { 484 file = f; 485 key = new String(Base64.decode(f.getName())); 486 } 487 488 @Override 489 public int compareTo(DecodedFilename other) { 490 // sorts into ascending lexical order by decoded key 491 return key.compareTo(other.key); 492 } 493 } 494 495 // Return a list of the files in the given directory, sorted lexically by 496 // the Base64-decoded file name, not by the on-disk filename 497 private ArrayList<DecodedFilename> contentsByKey(File dir) { 498 File[] allFiles = dir.listFiles(); 499 if (allFiles == null || allFiles.length == 0) { 500 return null; 501 } 502 503 // Decode the filenames into keys then sort lexically by key 504 ArrayList<DecodedFilename> contents = new ArrayList<DecodedFilename>(); 505 for (File f : allFiles) { 506 contents.add(new DecodedFilename(f)); 507 } 508 Collections.sort(contents); 509 return contents; 510 } 511 512 @Override 513 public void finishRestore() { 514 if (DEBUG) Log.v(TAG, "finishRestore()"); 515 if (mRestoreType == RestoreDescription.TYPE_FULL_STREAM) { 516 resetFullRestoreState(); 517 } 518 mRestoreType = 0; 519 } 520 521 // ------------------------------------------------------------------------------------ 522 // Full restore handling 523 524 private void resetFullRestoreState() { 525 try { 526 mCurFullRestoreStream.close(); 527 } catch (IOException e) { 528 Log.w(TAG, "Unable to close full restore input stream"); 529 } 530 mCurFullRestoreStream = null; 531 mFullRestoreSocketStream = null; 532 mFullRestoreBuffer = null; 533 } 534 535 /** 536 * Ask the transport to provide data for the "current" package being restored. The 537 * transport then writes some data to the socket supplied to this call, and returns 538 * the number of bytes written. The system will then read that many bytes and 539 * stream them to the application's agent for restore, then will call this method again 540 * to receive the next chunk of the archive. This sequence will be repeated until the 541 * transport returns zero indicating that all of the package's data has been delivered 542 * (or returns a negative value indicating some sort of hard error condition at the 543 * transport level). 544 * 545 * <p>After this method returns zero, the system will then call 546 * {@link #getNextFullRestorePackage()} to begin the restore process for the next 547 * application, and the sequence begins again. 548 * 549 * @param socket The file descriptor that the transport will use for delivering the 550 * streamed archive. 551 * @return 0 when no more data for the current package is available. A positive value 552 * indicates the presence of that much data to be delivered to the app. A negative 553 * return value is treated as equivalent to {@link BackupTransport#TRANSPORT_ERROR}, 554 * indicating a fatal error condition that precludes further restore operations 555 * on the current dataset. 556 */ 557 @Override 558 public int getNextFullRestoreDataChunk(ParcelFileDescriptor socket) { 559 if (mRestoreType != RestoreDescription.TYPE_FULL_STREAM) { 560 throw new IllegalStateException("Asked for full restore data for non-stream package"); 561 } 562 563 // first chunk? 564 if (mCurFullRestoreStream == null) { 565 final String name = mRestorePackages[mRestorePackage].packageName; 566 if (DEBUG) Log.i(TAG, "Starting full restore of " + name); 567 File dataset = new File(mRestoreSetFullDir, name); 568 try { 569 mCurFullRestoreStream = new FileInputStream(dataset); 570 } catch (IOException e) { 571 // If we can't open the target package's tarball, we return the single-package 572 // error code and let the caller go on to the next package. 573 Log.e(TAG, "Unable to read archive for " + name); 574 return TRANSPORT_PACKAGE_REJECTED; 575 } 576 mFullRestoreSocketStream = new FileOutputStream(socket.getFileDescriptor()); 577 mFullRestoreBuffer = new byte[32*1024]; 578 } 579 580 int nRead; 581 try { 582 nRead = mCurFullRestoreStream.read(mFullRestoreBuffer); 583 if (nRead < 0) { 584 // EOF: tell the caller we're done 585 nRead = NO_MORE_DATA; 586 } else if (nRead == 0) { 587 // This shouldn't happen when reading a FileInputStream; we should always 588 // get either a positive nonzero byte count or -1. Log the situation and 589 // treat it as EOF. 590 Log.w(TAG, "read() of archive file returned 0; treating as EOF"); 591 nRead = NO_MORE_DATA; 592 } else { 593 if (DEBUG) { 594 Log.i(TAG, " delivering restore chunk: " + nRead); 595 } 596 mFullRestoreSocketStream.write(mFullRestoreBuffer, 0, nRead); 597 } 598 } catch (IOException e) { 599 return TRANSPORT_ERROR; // Hard error accessing the file; shouldn't happen 600 } finally { 601 // Most transports will need to explicitly close 'socket' here, but this transport 602 // is in the same process as the caller so it can leave it up to the backup manager 603 // to manage both socket fds. 604 } 605 606 return nRead; 607 } 608 609 /** 610 * If the OS encounters an error while processing {@link RestoreDescription#TYPE_FULL_STREAM} 611 * data for restore, it will invoke this method to tell the transport that it should 612 * abandon the data download for the current package. The OS will then either call 613 * {@link #nextRestorePackage()} again to move on to restoring the next package in the 614 * set being iterated over, or will call {@link #finishRestore()} to shut down the restore 615 * operation. 616 * 617 * @return {@link #TRANSPORT_OK} if the transport was successful in shutting down the 618 * current stream cleanly, or {@link #TRANSPORT_ERROR} to indicate a serious 619 * transport-level failure. If the transport reports an error here, the entire restore 620 * operation will immediately be finished with no further attempts to restore app data. 621 */ 622 @Override 623 public int abortFullRestore() { 624 if (mRestoreType != RestoreDescription.TYPE_FULL_STREAM) { 625 throw new IllegalStateException("abortFullRestore() but not currently restoring"); 626 } 627 resetFullRestoreState(); 628 mRestoreType = 0; 629 return TRANSPORT_OK; 630 } 631 632} 633