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 17package com.android.providers.settings; 18 19import java.io.BufferedReader; 20import java.io.BufferedWriter; 21import java.io.DataInputStream; 22import java.io.DataOutputStream; 23import java.io.EOFException; 24import java.io.File; 25import java.io.FileInputStream; 26import java.io.FileOutputStream; 27import java.io.FileReader; 28import java.io.FileWriter; 29import java.io.IOException; 30import java.util.Arrays; 31import java.util.zip.CRC32; 32 33import android.app.backup.BackupDataInput; 34import android.app.backup.BackupDataOutput; 35import android.app.backup.BackupAgentHelper; 36import android.content.ContentValues; 37import android.content.Context; 38import android.database.Cursor; 39import android.net.Uri; 40import android.net.wifi.WifiManager; 41import android.os.FileUtils; 42import android.os.ParcelFileDescriptor; 43import android.os.Process; 44import android.provider.Settings; 45import android.text.TextUtils; 46import android.util.Log; 47 48/** 49 * Performs backup and restore of the System and Secure settings. 50 * List of settings that are backed up are stored in the Settings.java file 51 */ 52public class SettingsBackupAgent extends BackupAgentHelper { 53 private static final boolean DEBUG = false; 54 55 private static final String KEY_SYSTEM = "system"; 56 private static final String KEY_SECURE = "secure"; 57 private static final String KEY_LOCALE = "locale"; 58 59 // Versioning of the state file. Increment this version 60 // number any time the set of state items is altered. 61 private static final int STATE_VERSION = 1; 62 63 private static final int STATE_SYSTEM = 0; 64 private static final int STATE_SECURE = 1; 65 private static final int STATE_LOCALE = 2; 66 private static final int STATE_WIFI = 3; 67 private static final int STATE_SIZE = 4; // The number of state items 68 69 private static String[] sortedSystemKeys = null; 70 private static String[] sortedSecureKeys = null; 71 72 private static final byte[] EMPTY_DATA = new byte[0]; 73 74 private static final String TAG = "SettingsBackupAgent"; 75 76 private static final int COLUMN_NAME = 1; 77 private static final int COLUMN_VALUE = 2; 78 79 private static final String[] PROJECTION = { 80 Settings.NameValueTable._ID, 81 Settings.NameValueTable.NAME, 82 Settings.NameValueTable.VALUE 83 }; 84 85 private static final String FILE_WIFI_SUPPLICANT = "/data/misc/wifi/wpa_supplicant.conf"; 86 private static final String FILE_WIFI_SUPPLICANT_TEMPLATE = 87 "/system/etc/wifi/wpa_supplicant.conf"; 88 89 // the key to store the WIFI data under, should be sorted as last, so restore happens last. 90 // use very late unicode character to quasi-guarantee last sort position. 91 private static final String KEY_WIFI_SUPPLICANT = "\uffedWIFI"; 92 93 private SettingsHelper mSettingsHelper; 94 95 public void onCreate() { 96 mSettingsHelper = new SettingsHelper(this); 97 super.onCreate(); 98 } 99 100 @Override 101 public void onBackup(ParcelFileDescriptor oldState, BackupDataOutput data, 102 ParcelFileDescriptor newState) throws IOException { 103 104 byte[] systemSettingsData = getSystemSettings(); 105 byte[] secureSettingsData = getSecureSettings(); 106 byte[] locale = mSettingsHelper.getLocaleData(); 107 byte[] wifiData = getWifiSupplicant(FILE_WIFI_SUPPLICANT); 108 109 long[] stateChecksums = readOldChecksums(oldState); 110 111 stateChecksums[STATE_SYSTEM] = 112 writeIfChanged(stateChecksums[STATE_SYSTEM], KEY_SYSTEM, systemSettingsData, data); 113 stateChecksums[STATE_SECURE] = 114 writeIfChanged(stateChecksums[STATE_SECURE], KEY_SECURE, secureSettingsData, data); 115 stateChecksums[STATE_LOCALE] = 116 writeIfChanged(stateChecksums[STATE_LOCALE], KEY_LOCALE, locale, data); 117 stateChecksums[STATE_WIFI] = 118 writeIfChanged(stateChecksums[STATE_WIFI], KEY_WIFI_SUPPLICANT, wifiData, data); 119 120 writeNewChecksums(stateChecksums, newState); 121 } 122 123 @Override 124 public void onRestore(BackupDataInput data, int appVersionCode, 125 ParcelFileDescriptor newState) throws IOException { 126 127 while (data.readNextHeader()) { 128 final String key = data.getKey(); 129 final int size = data.getDataSize(); 130 if (KEY_SYSTEM.equals(key)) { 131 restoreSettings(data, Settings.System.CONTENT_URI); 132 mSettingsHelper.applyAudioSettings(); 133 } else if (KEY_SECURE.equals(key)) { 134 restoreSettings(data, Settings.Secure.CONTENT_URI); 135 } else if (KEY_WIFI_SUPPLICANT.equals(key)) { 136 int retainedWifiState = enableWifi(false); 137 restoreWifiSupplicant(FILE_WIFI_SUPPLICANT, data); 138 FileUtils.setPermissions(FILE_WIFI_SUPPLICANT, 139 FileUtils.S_IRUSR | FileUtils.S_IWUSR | 140 FileUtils.S_IRGRP | FileUtils.S_IWGRP, 141 Process.myUid(), Process.WIFI_UID); 142 // retain the previous WIFI state. 143 enableWifi(retainedWifiState == WifiManager.WIFI_STATE_ENABLED || 144 retainedWifiState == WifiManager.WIFI_STATE_ENABLING); 145 } else if (KEY_LOCALE.equals(key)) { 146 byte[] localeData = new byte[size]; 147 data.readEntityData(localeData, 0, size); 148 mSettingsHelper.setLocaleData(localeData); 149 } else { 150 data.skipEntityData(); 151 } 152 } 153 } 154 155 private long[] readOldChecksums(ParcelFileDescriptor oldState) throws IOException { 156 long[] stateChecksums = new long[STATE_SIZE]; 157 158 DataInputStream dataInput = new DataInputStream( 159 new FileInputStream(oldState.getFileDescriptor())); 160 161 try { 162 int stateVersion = dataInput.readInt(); 163 if (stateVersion == STATE_VERSION) { 164 for (int i = 0; i < STATE_SIZE; i++) { 165 stateChecksums[i] = dataInput.readLong(); 166 } 167 } 168 } catch (EOFException eof) { 169 // With the default 0 checksum we'll wind up forcing a backup of 170 // any unhandled data sets, which is appropriate. 171 } 172 dataInput.close(); 173 return stateChecksums; 174 } 175 176 private void writeNewChecksums(long[] checksums, ParcelFileDescriptor newState) 177 throws IOException { 178 DataOutputStream dataOutput = new DataOutputStream( 179 new FileOutputStream(newState.getFileDescriptor())); 180 181 dataOutput.writeInt(STATE_VERSION); 182 for (int i = 0; i < STATE_SIZE; i++) { 183 dataOutput.writeLong(checksums[i]); 184 } 185 dataOutput.close(); 186 } 187 188 private long writeIfChanged(long oldChecksum, String key, byte[] data, 189 BackupDataOutput output) { 190 CRC32 checkSummer = new CRC32(); 191 checkSummer.update(data); 192 long newChecksum = checkSummer.getValue(); 193 if (oldChecksum == newChecksum) { 194 return oldChecksum; 195 } 196 try { 197 output.writeEntityHeader(key, data.length); 198 output.writeEntityData(data, data.length); 199 } catch (IOException ioe) { 200 // Bail 201 } 202 return newChecksum; 203 } 204 205 private byte[] getSystemSettings() { 206 Cursor sortedCursor = getContentResolver().query(Settings.System.CONTENT_URI, PROJECTION, 207 null, null, Settings.NameValueTable.NAME); 208 // Copy and sort the array 209 if (sortedSystemKeys == null) { 210 sortedSystemKeys = copyAndSort(Settings.System.SETTINGS_TO_BACKUP); 211 } 212 byte[] result = extractRelevantValues(sortedCursor, sortedSystemKeys); 213 sortedCursor.close(); 214 return result; 215 } 216 217 private byte[] getSecureSettings() { 218 Cursor sortedCursor = getContentResolver().query(Settings.Secure.CONTENT_URI, PROJECTION, 219 null, null, Settings.NameValueTable.NAME); 220 // Copy and sort the array 221 if (sortedSecureKeys == null) { 222 sortedSecureKeys = copyAndSort(Settings.Secure.SETTINGS_TO_BACKUP); 223 } 224 byte[] result = extractRelevantValues(sortedCursor, sortedSecureKeys); 225 sortedCursor.close(); 226 return result; 227 } 228 229 private void restoreSettings(BackupDataInput data, Uri contentUri) { 230 if (DEBUG) Log.i(TAG, "restoreSettings: " + contentUri); 231 String[] whitelist = null; 232 if (contentUri.equals(Settings.Secure.CONTENT_URI)) { 233 whitelist = Settings.Secure.SETTINGS_TO_BACKUP; 234 } else if (contentUri.equals(Settings.System.CONTENT_URI)) { 235 whitelist = Settings.System.SETTINGS_TO_BACKUP; 236 } 237 238 ContentValues cv = new ContentValues(2); 239 byte[] settings = new byte[data.getDataSize()]; 240 try { 241 data.readEntityData(settings, 0, settings.length); 242 } catch (IOException ioe) { 243 Log.e(TAG, "Couldn't read entity data"); 244 return; 245 } 246 int pos = 0; 247 while (pos < settings.length) { 248 int length = readInt(settings, pos); 249 pos += 4; 250 String settingName = length > 0? new String(settings, pos, length) : null; 251 pos += length; 252 length = readInt(settings, pos); 253 pos += 4; 254 String settingValue = length > 0? new String(settings, pos, length) : null; 255 pos += length; 256 if (!TextUtils.isEmpty(settingName) && !TextUtils.isEmpty(settingValue)) { 257 //Log.i(TAG, "Restore " + settingName + " = " + settingValue); 258 259 // Only restore settings in our list of known-acceptable data 260 if (invalidSavedSetting(whitelist, settingName)) { 261 continue; 262 } 263 264 if (mSettingsHelper.restoreValue(settingName, settingValue)) { 265 cv.clear(); 266 cv.put(Settings.NameValueTable.NAME, settingName); 267 cv.put(Settings.NameValueTable.VALUE, settingValue); 268 getContentResolver().insert(contentUri, cv); 269 } 270 } 271 } 272 } 273 274 // Returns 'true' if the given setting is one that we refuse to restore 275 private boolean invalidSavedSetting(String[] knownNames, String candidate) { 276 // no filter? allow everything 277 if (knownNames == null) { 278 return false; 279 } 280 281 // whitelisted setting? allow it 282 for (String name : knownNames) { 283 if (name.equals(candidate)) { 284 return false; 285 } 286 } 287 288 // refuse everything else 289 if (DEBUG) Log.v(TAG, "Ignoring restore datum: " + candidate); 290 return true; 291 } 292 293 private String[] copyAndSort(String[] keys) { 294 String[] sortedKeys = new String[keys.length]; 295 System.arraycopy(keys, 0, sortedKeys, 0, keys.length); 296 Arrays.sort(sortedKeys); 297 return sortedKeys; 298 } 299 300 /** 301 * Given a cursor sorted by key name and a set of keys sorted by name, 302 * extract the required keys and values and write them to a byte array. 303 * @param sortedCursor 304 * @param sortedKeys 305 * @return 306 */ 307 byte[] extractRelevantValues(Cursor sortedCursor, String[] sortedKeys) { 308 byte[][] values = new byte[sortedKeys.length * 2][]; // keys and values 309 if (!sortedCursor.moveToFirst()) { 310 Log.e(TAG, "Couldn't read from the cursor"); 311 return new byte[0]; 312 } 313 int keyIndex = 0; 314 int totalSize = 0; 315 while (!sortedCursor.isAfterLast()) { 316 String name = sortedCursor.getString(COLUMN_NAME); 317 while (sortedKeys[keyIndex].compareTo(name.toString()) < 0) { 318 keyIndex++; 319 if (keyIndex == sortedKeys.length) break; 320 } 321 if (keyIndex < sortedKeys.length && name.equals(sortedKeys[keyIndex])) { 322 String value = sortedCursor.getString(COLUMN_VALUE); 323 byte[] nameBytes = name.toString().getBytes(); 324 totalSize += 4 + nameBytes.length; 325 values[keyIndex * 2] = nameBytes; 326 byte[] valueBytes; 327 if (TextUtils.isEmpty(value)) { 328 valueBytes = null; 329 totalSize += 4; 330 } else { 331 valueBytes = value.toString().getBytes(); 332 totalSize += 4 + valueBytes.length; 333 //Log.i(TAG, "Backing up " + name + " = " + value); 334 } 335 values[keyIndex * 2 + 1] = valueBytes; 336 keyIndex++; 337 } 338 if (keyIndex == sortedKeys.length || !sortedCursor.moveToNext()) { 339 break; 340 } 341 } 342 343 byte[] result = new byte[totalSize]; 344 int pos = 0; 345 for (int i = 0; i < sortedKeys.length * 2; i++) { 346 if (values[i] != null) { 347 pos = writeInt(result, pos, values[i].length); 348 pos = writeBytes(result, pos, values[i]); 349 } 350 } 351 return result; 352 } 353 354 private byte[] getWifiSupplicant(String filename) { 355 try { 356 File file = new File(filename); 357 if (file.exists()) { 358 BufferedReader br = new BufferedReader(new FileReader(file)); 359 StringBuffer relevantLines = new StringBuffer(); 360 boolean started = false; 361 String line; 362 while ((line = br.readLine()) != null) { 363 if (!started && line.startsWith("network")) { 364 started = true; 365 } 366 if (started) { 367 relevantLines.append(line).append("\n"); 368 } 369 } 370 if (relevantLines.length() > 0) { 371 return relevantLines.toString().getBytes(); 372 } else { 373 return EMPTY_DATA; 374 } 375 } else { 376 return EMPTY_DATA; 377 } 378 } catch (IOException ioe) { 379 Log.w(TAG, "Couldn't backup " + filename); 380 return EMPTY_DATA; 381 } 382 } 383 384 private void restoreWifiSupplicant(String filename, BackupDataInput data) { 385 byte[] bytes = new byte[data.getDataSize()]; 386 if (bytes.length <= 0) return; 387 try { 388 data.readEntityData(bytes, 0, bytes.length); 389 File supplicantFile = new File(FILE_WIFI_SUPPLICANT); 390 if (supplicantFile.exists()) supplicantFile.delete(); 391 copyWifiSupplicantTemplate(); 392 393 FileOutputStream fos = new FileOutputStream(filename, true); 394 fos.write("\n".getBytes()); 395 fos.write(bytes); 396 } catch (IOException ioe) { 397 Log.w(TAG, "Couldn't restore " + filename); 398 } 399 } 400 401 private void copyWifiSupplicantTemplate() { 402 try { 403 BufferedReader br = new BufferedReader(new FileReader(FILE_WIFI_SUPPLICANT_TEMPLATE)); 404 BufferedWriter bw = new BufferedWriter(new FileWriter(FILE_WIFI_SUPPLICANT)); 405 char[] temp = new char[1024]; 406 int size; 407 while ((size = br.read(temp)) > 0) { 408 bw.write(temp, 0, size); 409 } 410 bw.close(); 411 br.close(); 412 } catch (IOException ioe) { 413 Log.w(TAG, "Couldn't copy wpa_supplicant file"); 414 } 415 } 416 417 /** 418 * Write an int in BigEndian into the byte array. 419 * @param out byte array 420 * @param pos current pos in array 421 * @param value integer to write 422 * @return the index after adding the size of an int (4) 423 */ 424 private int writeInt(byte[] out, int pos, int value) { 425 out[pos + 0] = (byte) ((value >> 24) & 0xFF); 426 out[pos + 1] = (byte) ((value >> 16) & 0xFF); 427 out[pos + 2] = (byte) ((value >> 8) & 0xFF); 428 out[pos + 3] = (byte) ((value >> 0) & 0xFF); 429 return pos + 4; 430 } 431 432 private int writeBytes(byte[] out, int pos, byte[] value) { 433 System.arraycopy(value, 0, out, pos, value.length); 434 return pos + value.length; 435 } 436 437 private int readInt(byte[] in, int pos) { 438 int result = 439 ((in[pos ] & 0xFF) << 24) | 440 ((in[pos + 1] & 0xFF) << 16) | 441 ((in[pos + 2] & 0xFF) << 8) | 442 ((in[pos + 3] & 0xFF) << 0); 443 return result; 444 } 445 446 private int enableWifi(boolean enable) { 447 WifiManager wfm = (WifiManager) getSystemService(Context.WIFI_SERVICE); 448 if (wfm != null) { 449 int state = wfm.getWifiState(); 450 wfm.setWifiEnabled(enable); 451 return state; 452 } 453 return WifiManager.WIFI_STATE_UNKNOWN; 454 } 455} 456