1 /* 2 * Copyright (C) 2012 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.server.updates; 18 19 import com.android.server.EventLogTags; 20 import com.android.internal.util.HexDump; 21 22 import android.content.BroadcastReceiver; 23 import android.content.Context; 24 import android.content.Intent; 25 import android.net.Uri; 26 import android.util.EventLog; 27 import android.util.Slog; 28 29 import java.io.File; 30 import java.io.FileOutputStream; 31 import java.io.IOException; 32 import java.io.InputStream; 33 import java.security.MessageDigest; 34 import java.security.NoSuchAlgorithmException; 35 36 import libcore.io.IoUtils; 37 import libcore.io.Streams; 38 39 public class ConfigUpdateInstallReceiver extends BroadcastReceiver { 40 41 private static final String TAG = "ConfigUpdateInstallReceiver"; 42 43 private static final String EXTRA_REQUIRED_HASH = "REQUIRED_HASH"; 44 private static final String EXTRA_VERSION_NUMBER = "VERSION"; 45 46 protected final File updateDir; 47 protected final File updateContent; 48 protected final File updateVersion; 49 ConfigUpdateInstallReceiver(String updateDir, String updateContentPath, String updateMetadataPath, String updateVersionPath)50 public ConfigUpdateInstallReceiver(String updateDir, String updateContentPath, 51 String updateMetadataPath, String updateVersionPath) { 52 this.updateDir = new File(updateDir); 53 this.updateContent = new File(updateDir, updateContentPath); 54 File updateMetadataDir = new File(updateDir, updateMetadataPath); 55 this.updateVersion = new File(updateMetadataDir, updateVersionPath); 56 } 57 58 @Override onReceive(final Context context, final Intent intent)59 public void onReceive(final Context context, final Intent intent) { 60 new Thread() { 61 @Override 62 public void run() { 63 try { 64 // get the content path from the extras 65 byte[] altContent = getAltContent(context, intent); 66 // get the version from the extras 67 int altVersion = getVersionFromIntent(intent); 68 // get the previous value from the extras 69 String altRequiredHash = getRequiredHashFromIntent(intent); 70 // get the version currently being used 71 int currentVersion = getCurrentVersion(); 72 // get the hash of the currently used value 73 String currentHash = getCurrentHash(getCurrentContent()); 74 if (!verifyVersion(currentVersion, altVersion)) { 75 Slog.i(TAG, "Not installing, new version is <= current version"); 76 } else if (!verifyPreviousHash(currentHash, altRequiredHash)) { 77 EventLog.writeEvent(EventLogTags.CONFIG_INSTALL_FAILED, 78 "Current hash did not match required value"); 79 } else { 80 // install the new content 81 Slog.i(TAG, "Found new update, installing..."); 82 install(altContent, altVersion); 83 Slog.i(TAG, "Installation successful"); 84 postInstall(context, intent); 85 } 86 } catch (Exception e) { 87 Slog.e(TAG, "Could not update content!", e); 88 // keep the error message <= 100 chars 89 String errMsg = e.toString(); 90 if (errMsg.length() > 100) { 91 errMsg = errMsg.substring(0, 99); 92 } 93 EventLog.writeEvent(EventLogTags.CONFIG_INSTALL_FAILED, errMsg); 94 } 95 } 96 }.start(); 97 } 98 getContentFromIntent(Intent i)99 private Uri getContentFromIntent(Intent i) { 100 Uri data = i.getData(); 101 if (data == null) { 102 throw new IllegalStateException("Missing required content path, ignoring."); 103 } 104 return data; 105 } 106 getVersionFromIntent(Intent i)107 private int getVersionFromIntent(Intent i) throws NumberFormatException { 108 String extraValue = i.getStringExtra(EXTRA_VERSION_NUMBER); 109 if (extraValue == null) { 110 throw new IllegalStateException("Missing required version number, ignoring."); 111 } 112 return Integer.parseInt(extraValue.trim()); 113 } 114 getRequiredHashFromIntent(Intent i)115 private String getRequiredHashFromIntent(Intent i) { 116 String extraValue = i.getStringExtra(EXTRA_REQUIRED_HASH); 117 if (extraValue == null) { 118 throw new IllegalStateException("Missing required previous hash, ignoring."); 119 } 120 return extraValue.trim(); 121 } 122 getCurrentVersion()123 private int getCurrentVersion() throws NumberFormatException { 124 try { 125 String strVersion = IoUtils.readFileAsString(updateVersion.getCanonicalPath()).trim(); 126 return Integer.parseInt(strVersion); 127 } catch (IOException e) { 128 Slog.i(TAG, "Couldn't find current metadata, assuming first update"); 129 return 0; 130 } 131 } 132 getAltContent(Context c, Intent i)133 private byte[] getAltContent(Context c, Intent i) throws IOException { 134 Uri content = getContentFromIntent(i); 135 InputStream is = c.getContentResolver().openInputStream(content); 136 try { 137 return Streams.readFullyNoClose(is); 138 } finally { 139 is.close(); 140 } 141 } 142 getCurrentContent()143 private byte[] getCurrentContent() { 144 try { 145 return IoUtils.readFileAsByteArray(updateContent.getCanonicalPath()); 146 } catch (IOException e) { 147 Slog.i(TAG, "Failed to read current content, assuming first update!"); 148 return null; 149 } 150 } 151 getCurrentHash(byte[] content)152 private static String getCurrentHash(byte[] content) { 153 if (content == null) { 154 return "0"; 155 } 156 try { 157 MessageDigest dgst = MessageDigest.getInstance("SHA512"); 158 byte[] fingerprint = dgst.digest(content); 159 return HexDump.toHexString(fingerprint, false); 160 } catch (NoSuchAlgorithmException e) { 161 throw new AssertionError(e); 162 } 163 } 164 verifyVersion(int current, int alternative)165 private boolean verifyVersion(int current, int alternative) { 166 return (current < alternative); 167 } 168 verifyPreviousHash(String current, String required)169 private boolean verifyPreviousHash(String current, String required) { 170 // this is an optional value- if the required field is NONE then we ignore it 171 if (required.equals("NONE")) { 172 return true; 173 } 174 // otherwise, verify that we match correctly 175 return current.equals(required); 176 } 177 writeUpdate(File dir, File file, byte[] content)178 protected void writeUpdate(File dir, File file, byte[] content) throws IOException { 179 FileOutputStream out = null; 180 File tmp = null; 181 try { 182 // create the parents for the destination file 183 File parent = file.getParentFile(); 184 parent.mkdirs(); 185 // check that they were created correctly 186 if (!parent.exists()) { 187 throw new IOException("Failed to create directory " + parent.getCanonicalPath()); 188 } 189 // create the temporary file 190 tmp = File.createTempFile("journal", "", dir); 191 // mark tmp -rw-r--r-- 192 tmp.setReadable(true, false); 193 // write to it 194 out = new FileOutputStream(tmp); 195 out.write(content); 196 // sync to disk 197 out.getFD().sync(); 198 // atomic rename 199 if (!tmp.renameTo(file)) { 200 throw new IOException("Failed to atomically rename " + file.getCanonicalPath()); 201 } 202 } finally { 203 if (tmp != null) { 204 tmp.delete(); 205 } 206 IoUtils.closeQuietly(out); 207 } 208 } 209 install(byte[] content, int version)210 protected void install(byte[] content, int version) throws IOException { 211 writeUpdate(updateDir, updateContent, content); 212 writeUpdate(updateDir, updateVersion, Long.toString(version).getBytes()); 213 } 214 postInstall(Context context, Intent intent)215 protected void postInstall(Context context, Intent intent) { 216 } 217 } 218