/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.providers.settings;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Arrays;
import java.util.zip.CRC32;
import android.app.backup.BackupDataInput;
import android.app.backup.BackupDataOutput;
import android.app.backup.BackupAgentHelper;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.net.wifi.WifiManager;
import android.os.FileUtils;
import android.os.ParcelFileDescriptor;
import android.os.Process;
import android.provider.Settings;
import android.text.TextUtils;
import android.util.Log;
/**
* Performs backup and restore of the System and Secure settings.
* List of settings that are backed up are stored in the Settings.java file
*/
public class SettingsBackupAgent extends BackupAgentHelper {
private static final boolean DEBUG = false;
private static final String KEY_SYSTEM = "system";
private static final String KEY_SECURE = "secure";
private static final String KEY_LOCALE = "locale";
// Versioning of the state file. Increment this version
// number any time the set of state items is altered.
private static final int STATE_VERSION = 1;
private static final int STATE_SYSTEM = 0;
private static final int STATE_SECURE = 1;
private static final int STATE_LOCALE = 2;
private static final int STATE_WIFI = 3;
private static final int STATE_SIZE = 4; // The number of state items
private static String[] sortedSystemKeys = null;
private static String[] sortedSecureKeys = null;
private static final byte[] EMPTY_DATA = new byte[0];
private static final String TAG = "SettingsBackupAgent";
private static final int COLUMN_NAME = 1;
private static final int COLUMN_VALUE = 2;
private static final String[] PROJECTION = {
Settings.NameValueTable._ID,
Settings.NameValueTable.NAME,
Settings.NameValueTable.VALUE
};
private static final String FILE_WIFI_SUPPLICANT = "/data/misc/wifi/wpa_supplicant.conf";
private static final String FILE_WIFI_SUPPLICANT_TEMPLATE =
"/system/etc/wifi/wpa_supplicant.conf";
// the key to store the WIFI data under, should be sorted as last, so restore happens last.
// use very late unicode character to quasi-guarantee last sort position.
private static final String KEY_WIFI_SUPPLICANT = "\uffedWIFI";
private SettingsHelper mSettingsHelper;
public void onCreate() {
mSettingsHelper = new SettingsHelper(this);
super.onCreate();
}
@Override
public void onBackup(ParcelFileDescriptor oldState, BackupDataOutput data,
ParcelFileDescriptor newState) throws IOException {
byte[] systemSettingsData = getSystemSettings();
byte[] secureSettingsData = getSecureSettings();
byte[] locale = mSettingsHelper.getLocaleData();
byte[] wifiData = getWifiSupplicant(FILE_WIFI_SUPPLICANT);
long[] stateChecksums = readOldChecksums(oldState);
stateChecksums[STATE_SYSTEM] =
writeIfChanged(stateChecksums[STATE_SYSTEM], KEY_SYSTEM, systemSettingsData, data);
stateChecksums[STATE_SECURE] =
writeIfChanged(stateChecksums[STATE_SECURE], KEY_SECURE, secureSettingsData, data);
stateChecksums[STATE_LOCALE] =
writeIfChanged(stateChecksums[STATE_LOCALE], KEY_LOCALE, locale, data);
stateChecksums[STATE_WIFI] =
writeIfChanged(stateChecksums[STATE_WIFI], KEY_WIFI_SUPPLICANT, wifiData, data);
writeNewChecksums(stateChecksums, newState);
}
@Override
public void onRestore(BackupDataInput data, int appVersionCode,
ParcelFileDescriptor newState) throws IOException {
while (data.readNextHeader()) {
final String key = data.getKey();
final int size = data.getDataSize();
if (KEY_SYSTEM.equals(key)) {
restoreSettings(data, Settings.System.CONTENT_URI);
mSettingsHelper.applyAudioSettings();
} else if (KEY_SECURE.equals(key)) {
restoreSettings(data, Settings.Secure.CONTENT_URI);
} else if (KEY_WIFI_SUPPLICANT.equals(key)) {
int retainedWifiState = enableWifi(false);
restoreWifiSupplicant(FILE_WIFI_SUPPLICANT, data);
FileUtils.setPermissions(FILE_WIFI_SUPPLICANT,
FileUtils.S_IRUSR | FileUtils.S_IWUSR |
FileUtils.S_IRGRP | FileUtils.S_IWGRP,
Process.myUid(), Process.WIFI_UID);
// retain the previous WIFI state.
enableWifi(retainedWifiState == WifiManager.WIFI_STATE_ENABLED ||
retainedWifiState == WifiManager.WIFI_STATE_ENABLING);
} else if (KEY_LOCALE.equals(key)) {
byte[] localeData = new byte[size];
data.readEntityData(localeData, 0, size);
mSettingsHelper.setLocaleData(localeData);
} else {
data.skipEntityData();
}
}
}
private long[] readOldChecksums(ParcelFileDescriptor oldState) throws IOException {
long[] stateChecksums = new long[STATE_SIZE];
DataInputStream dataInput = new DataInputStream(
new FileInputStream(oldState.getFileDescriptor()));
try {
int stateVersion = dataInput.readInt();
if (stateVersion == STATE_VERSION) {
for (int i = 0; i < STATE_SIZE; i++) {
stateChecksums[i] = dataInput.readLong();
}
}
} catch (EOFException eof) {
// With the default 0 checksum we'll wind up forcing a backup of
// any unhandled data sets, which is appropriate.
}
dataInput.close();
return stateChecksums;
}
private void writeNewChecksums(long[] checksums, ParcelFileDescriptor newState)
throws IOException {
DataOutputStream dataOutput = new DataOutputStream(
new FileOutputStream(newState.getFileDescriptor()));
dataOutput.writeInt(STATE_VERSION);
for (int i = 0; i < STATE_SIZE; i++) {
dataOutput.writeLong(checksums[i]);
}
dataOutput.close();
}
private long writeIfChanged(long oldChecksum, String key, byte[] data,
BackupDataOutput output) {
CRC32 checkSummer = new CRC32();
checkSummer.update(data);
long newChecksum = checkSummer.getValue();
if (oldChecksum == newChecksum) {
return oldChecksum;
}
try {
output.writeEntityHeader(key, data.length);
output.writeEntityData(data, data.length);
} catch (IOException ioe) {
// Bail
}
return newChecksum;
}
private byte[] getSystemSettings() {
Cursor sortedCursor = getContentResolver().query(Settings.System.CONTENT_URI, PROJECTION,
null, null, Settings.NameValueTable.NAME);
// Copy and sort the array
if (sortedSystemKeys == null) {
sortedSystemKeys = copyAndSort(Settings.System.SETTINGS_TO_BACKUP);
}
byte[] result = extractRelevantValues(sortedCursor, sortedSystemKeys);
sortedCursor.close();
return result;
}
private byte[] getSecureSettings() {
Cursor sortedCursor = getContentResolver().query(Settings.Secure.CONTENT_URI, PROJECTION,
null, null, Settings.NameValueTable.NAME);
// Copy and sort the array
if (sortedSecureKeys == null) {
sortedSecureKeys = copyAndSort(Settings.Secure.SETTINGS_TO_BACKUP);
}
byte[] result = extractRelevantValues(sortedCursor, sortedSecureKeys);
sortedCursor.close();
return result;
}
private void restoreSettings(BackupDataInput data, Uri contentUri) {
if (DEBUG) Log.i(TAG, "restoreSettings: " + contentUri);
String[] whitelist = null;
if (contentUri.equals(Settings.Secure.CONTENT_URI)) {
whitelist = Settings.Secure.SETTINGS_TO_BACKUP;
} else if (contentUri.equals(Settings.System.CONTENT_URI)) {
whitelist = Settings.System.SETTINGS_TO_BACKUP;
}
ContentValues cv = new ContentValues(2);
byte[] settings = new byte[data.getDataSize()];
try {
data.readEntityData(settings, 0, settings.length);
} catch (IOException ioe) {
Log.e(TAG, "Couldn't read entity data");
return;
}
int pos = 0;
while (pos < settings.length) {
int length = readInt(settings, pos);
pos += 4;
String settingName = length > 0? new String(settings, pos, length) : null;
pos += length;
length = readInt(settings, pos);
pos += 4;
String settingValue = length > 0? new String(settings, pos, length) : null;
pos += length;
if (!TextUtils.isEmpty(settingName) && !TextUtils.isEmpty(settingValue)) {
//Log.i(TAG, "Restore " + settingName + " = " + settingValue);
// Only restore settings in our list of known-acceptable data
if (invalidSavedSetting(whitelist, settingName)) {
continue;
}
if (mSettingsHelper.restoreValue(settingName, settingValue)) {
cv.clear();
cv.put(Settings.NameValueTable.NAME, settingName);
cv.put(Settings.NameValueTable.VALUE, settingValue);
getContentResolver().insert(contentUri, cv);
}
}
}
}
// Returns 'true' if the given setting is one that we refuse to restore
private boolean invalidSavedSetting(String[] knownNames, String candidate) {
// no filter? allow everything
if (knownNames == null) {
return false;
}
// whitelisted setting? allow it
for (String name : knownNames) {
if (name.equals(candidate)) {
return false;
}
}
// refuse everything else
if (DEBUG) Log.v(TAG, "Ignoring restore datum: " + candidate);
return true;
}
private String[] copyAndSort(String[] keys) {
String[] sortedKeys = new String[keys.length];
System.arraycopy(keys, 0, sortedKeys, 0, keys.length);
Arrays.sort(sortedKeys);
return sortedKeys;
}
/**
* Given a cursor sorted by key name and a set of keys sorted by name,
* extract the required keys and values and write them to a byte array.
* @param sortedCursor
* @param sortedKeys
* @return
*/
byte[] extractRelevantValues(Cursor sortedCursor, String[] sortedKeys) {
byte[][] values = new byte[sortedKeys.length * 2][]; // keys and values
if (!sortedCursor.moveToFirst()) {
Log.e(TAG, "Couldn't read from the cursor");
return new byte[0];
}
int keyIndex = 0;
int totalSize = 0;
while (!sortedCursor.isAfterLast()) {
String name = sortedCursor.getString(COLUMN_NAME);
while (sortedKeys[keyIndex].compareTo(name.toString()) < 0) {
keyIndex++;
if (keyIndex == sortedKeys.length) break;
}
if (keyIndex < sortedKeys.length && name.equals(sortedKeys[keyIndex])) {
String value = sortedCursor.getString(COLUMN_VALUE);
byte[] nameBytes = name.toString().getBytes();
totalSize += 4 + nameBytes.length;
values[keyIndex * 2] = nameBytes;
byte[] valueBytes;
if (TextUtils.isEmpty(value)) {
valueBytes = null;
totalSize += 4;
} else {
valueBytes = value.toString().getBytes();
totalSize += 4 + valueBytes.length;
//Log.i(TAG, "Backing up " + name + " = " + value);
}
values[keyIndex * 2 + 1] = valueBytes;
keyIndex++;
}
if (keyIndex == sortedKeys.length || !sortedCursor.moveToNext()) {
break;
}
}
byte[] result = new byte[totalSize];
int pos = 0;
for (int i = 0; i < sortedKeys.length * 2; i++) {
if (values[i] != null) {
pos = writeInt(result, pos, values[i].length);
pos = writeBytes(result, pos, values[i]);
}
}
return result;
}
private byte[] getWifiSupplicant(String filename) {
try {
File file = new File(filename);
if (file.exists()) {
BufferedReader br = new BufferedReader(new FileReader(file));
StringBuffer relevantLines = new StringBuffer();
boolean started = false;
String line;
while ((line = br.readLine()) != null) {
if (!started && line.startsWith("network")) {
started = true;
}
if (started) {
relevantLines.append(line).append("\n");
}
}
if (relevantLines.length() > 0) {
return relevantLines.toString().getBytes();
} else {
return EMPTY_DATA;
}
} else {
return EMPTY_DATA;
}
} catch (IOException ioe) {
Log.w(TAG, "Couldn't backup " + filename);
return EMPTY_DATA;
}
}
private void restoreWifiSupplicant(String filename, BackupDataInput data) {
byte[] bytes = new byte[data.getDataSize()];
if (bytes.length <= 0) return;
try {
data.readEntityData(bytes, 0, bytes.length);
File supplicantFile = new File(FILE_WIFI_SUPPLICANT);
if (supplicantFile.exists()) supplicantFile.delete();
copyWifiSupplicantTemplate();
FileOutputStream fos = new FileOutputStream(filename, true);
fos.write("\n".getBytes());
fos.write(bytes);
} catch (IOException ioe) {
Log.w(TAG, "Couldn't restore " + filename);
}
}
private void copyWifiSupplicantTemplate() {
try {
BufferedReader br = new BufferedReader(new FileReader(FILE_WIFI_SUPPLICANT_TEMPLATE));
BufferedWriter bw = new BufferedWriter(new FileWriter(FILE_WIFI_SUPPLICANT));
char[] temp = new char[1024];
int size;
while ((size = br.read(temp)) > 0) {
bw.write(temp, 0, size);
}
bw.close();
br.close();
} catch (IOException ioe) {
Log.w(TAG, "Couldn't copy wpa_supplicant file");
}
}
/**
* Write an int in BigEndian into the byte array.
* @param out byte array
* @param pos current pos in array
* @param value integer to write
* @return the index after adding the size of an int (4)
*/
private int writeInt(byte[] out, int pos, int value) {
out[pos + 0] = (byte) ((value >> 24) & 0xFF);
out[pos + 1] = (byte) ((value >> 16) & 0xFF);
out[pos + 2] = (byte) ((value >> 8) & 0xFF);
out[pos + 3] = (byte) ((value >> 0) & 0xFF);
return pos + 4;
}
private int writeBytes(byte[] out, int pos, byte[] value) {
System.arraycopy(value, 0, out, pos, value.length);
return pos + value.length;
}
private int readInt(byte[] in, int pos) {
int result =
((in[pos ] & 0xFF) << 24) |
((in[pos + 1] & 0xFF) << 16) |
((in[pos + 2] & 0xFF) << 8) |
((in[pos + 3] & 0xFF) << 0);
return result;
}
private int enableWifi(boolean enable) {
WifiManager wfm = (WifiManager) getSystemService(Context.WIFI_SERVICE);
if (wfm != null) {
int state = wfm.getWifiState();
wfm.setWifiEnabled(enable);
return state;
}
return WifiManager.WIFI_STATE_UNKNOWN;
}
}