1/* 2 * Copyright (C) 2015 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#include <errno.h> 18#include <ftw.h> 19#include <libgen.h> 20#include <stdarg.h> 21#include <stdio.h> 22#include <stdlib.h> 23#include <string.h> 24#include <unistd.h> 25#include <iostream> 26#include <memory> 27#include <string> 28#include <vector> 29 30#include "android-base/logging.h" 31 32static const char* TZDATA_FILENAME = "/tzdata"; 33// tzdata file header (as much as we need for the version): 34// byte[11] tzdata_version -- e.g. "tzdata2012f" 35static const int TZ_HEADER_LENGTH = 11; 36 37static void usage() { 38 std::cerr << "Usage: tzdatacheck SYSTEM_TZ_DIR DATA_TZ_DIR\n" 39 "\n" 40 "Compares the headers of two tzdata files. If the one in SYSTEM_TZ_DIR is the\n" 41 "same or a higher version than the one in DATA_TZ_DIR the DATA_TZ_DIR is renamed\n" 42 "and then deleted.\n"; 43 exit(1); 44} 45 46/* 47 * Opens a file and fills headerBytes with the first byteCount bytes from the file. It is a fatal 48 * error if the file is too small or cannot be opened. If the file does not exist false is returned. 49 * If the bytes were read successfully then true is returned. 50 */ 51static bool readHeader(const std::string& tzDataFileName, char* headerBytes, size_t byteCount) { 52 FILE* tzDataFile = fopen(tzDataFileName.c_str(), "r"); 53 if (tzDataFile == nullptr) { 54 if (errno == ENOENT) { 55 return false; 56 } else { 57 PLOG(FATAL) << "Error opening tzdata file " << tzDataFileName; 58 } 59 } 60 size_t bytesRead = fread(headerBytes, 1, byteCount, tzDataFile); 61 if (bytesRead != byteCount) { 62 LOG(FATAL) << tzDataFileName << " is too small. " << byteCount << " bytes required"; 63 } 64 fclose(tzDataFile); 65 return true; 66} 67 68/* Checks the contents of headerBytes. It is a fatal error if it not a tzdata header. */ 69static void checkValidHeader(const std::string& fileName, char* headerBytes) { 70 if (strncmp("tzdata", headerBytes, 6) != 0) { 71 LOG(FATAL) << fileName << " does not start with the expected bytes (tzdata)"; 72 } 73} 74 75/* Return the parent directory of dirName. */ 76static std::string getParentDir(const std::string& dirName) { 77 std::unique_ptr<char> mutable_dirname(strdup(dirName.c_str())); 78 return dirname(mutable_dirname.get()); 79} 80 81/* Deletes a single file, symlink or directory. Called from nftw(). */ 82static int deleteFn(const char* fpath, const struct stat*, int typeflag, struct FTW*) { 83 LOG(DEBUG) << "Inspecting " << fpath; 84 switch (typeflag) { 85 case FTW_F: 86 case FTW_SL: 87 LOG(DEBUG) << "Unlinking " << fpath; 88 if (unlink(fpath)) { 89 PLOG(WARNING) << "Failed to unlink file/symlink " << fpath; 90 } 91 break; 92 case FTW_D: 93 case FTW_DP: 94 LOG(DEBUG) << "Removing dir " << fpath; 95 if (rmdir(fpath)) { 96 PLOG(WARNING) << "Failed to remove dir " << fpath; 97 } 98 break; 99 default: 100 LOG(WARNING) << "Unsupported file type " << fpath << ": " << typeflag; 101 break; 102 } 103 return 0; 104} 105 106/* 107 * Deletes dirToDelete and returns true if it is successful in removing or moving the directory out 108 * of the way. If dirToDelete does not exist this function does nothing and returns true. 109 * 110 * During deletion, this function first renames the directory to a temporary name. If the temporary 111 * directory cannot be created, or the directory cannot be renamed, false is returned. After the 112 * rename, deletion of files and subdirs beneath the directory is performed on a "best effort" 113 * basis. Symlinks beneath the directory are not followed. 114 */ 115static bool deleteDir(const std::string& dirToDelete) { 116 // Check whether the dir exists. 117 struct stat buf; 118 if (stat(dirToDelete.c_str(), &buf) == 0) { 119 if (!S_ISDIR(buf.st_mode)) { 120 LOG(WARNING) << dirToDelete << " is not a directory"; 121 return false; 122 } 123 } else { 124 if (errno == ENOENT) { 125 PLOG(INFO) << "Directory does not exist: " << dirToDelete; 126 return true; 127 } else { 128 PLOG(WARNING) << "Unable to stat " << dirToDelete; 129 return false; 130 } 131 } 132 133 // First, rename dirToDelete. 134 std::string tempDirNameTemplate = getParentDir(dirToDelete); 135 tempDirNameTemplate += "/tempXXXXXX"; 136 137 // Create an empty directory with the temporary name. For this we need a non-const char*. 138 std::vector<char> tempDirName(tempDirNameTemplate.length() + 1); 139 strcpy(&tempDirName[0], tempDirNameTemplate.c_str()); 140 if (mkdtemp(&tempDirName[0]) == nullptr) { 141 PLOG(WARNING) << "Unable to create a temporary directory: " << tempDirNameTemplate; 142 return false; 143 } 144 145 // Rename dirToDelete to tempDirName. 146 int rc = rename(dirToDelete.c_str(), &tempDirName[0]); 147 if (rc == -1) { 148 PLOG(WARNING) << "Unable to rename directory from " << dirToDelete << " to " 149 << &tempDirName[0]; 150 return false; 151 } 152 153 // Recursively delete contents of tempDirName. 154 rc = nftw(&tempDirName[0], deleteFn, 10 /* openFiles */, 155 FTW_DEPTH | FTW_MOUNT | FTW_PHYS); 156 if (rc == -1) { 157 LOG(INFO) << "Could not delete directory: " << &tempDirName[0]; 158 } 159 return true; 160} 161 162/* 163 * After a platform update it is likely that timezone data found on the system partition will be 164 * newer than the version found in the data partition. This tool detects this case and removes the 165 * version in /data along with any update metadata. 166 * 167 * Note: This code is related to code in com.android.server.updates.TzDataInstallReceiver. The 168 * paths for the metadata and current timezone data must match. 169 * 170 * Typically on device the two args will be: 171 * /system/usr/share/zoneinfo /data/misc/zoneinfo 172 * 173 * See usage() for usage notes. 174 */ 175int main(int argc, char* argv[]) { 176 if (argc != 3) { 177 usage(); 178 } 179 180 const char* systemZoneInfoDir = argv[1]; 181 const char* dataZoneInfoDir = argv[2]; 182 183 std::string dataCurrentDirName(dataZoneInfoDir); 184 dataCurrentDirName += "/current"; 185 std::string dataTzDataFileName(dataCurrentDirName); 186 dataTzDataFileName += TZDATA_FILENAME; 187 188 std::vector<char> dataTzDataHeader; 189 dataTzDataHeader.reserve(TZ_HEADER_LENGTH); 190 191 bool dataFileExists = readHeader(dataTzDataFileName, dataTzDataHeader.data(), TZ_HEADER_LENGTH); 192 if (!dataFileExists) { 193 LOG(INFO) << "tzdata file " << dataTzDataFileName << " does not exist. No action required."; 194 return 0; 195 } 196 checkValidHeader(dataTzDataFileName, dataTzDataHeader.data()); 197 198 std::string systemTzDataFileName(systemZoneInfoDir); 199 systemTzDataFileName += TZDATA_FILENAME; 200 std::vector<char> systemTzDataHeader; 201 systemTzDataHeader.reserve(TZ_HEADER_LENGTH); 202 bool systemFileExists = 203 readHeader(systemTzDataFileName, systemTzDataHeader.data(), TZ_HEADER_LENGTH); 204 if (!systemFileExists) { 205 LOG(FATAL) << systemTzDataFileName << " does not exist or could not be opened"; 206 } 207 checkValidHeader(systemTzDataFileName, systemTzDataHeader.data()); 208 209 if (strncmp(&systemTzDataHeader[0], &dataTzDataHeader[0], TZ_HEADER_LENGTH) < 0) { 210 LOG(INFO) << "tzdata file " << dataTzDataFileName << " is the newer than " 211 << systemTzDataFileName << ". No action required."; 212 } else { 213 // We have detected the case this tool is intended to prevent. Go fix it. 214 LOG(INFO) << "tzdata file " << dataTzDataFileName << " is the same as or older than " 215 << systemTzDataFileName << "; fixing..."; 216 217 // Delete the update metadata 218 std::string dataUpdatesDirName(dataZoneInfoDir); 219 dataUpdatesDirName += "/updates"; 220 LOG(INFO) << "Removing: " << dataUpdatesDirName; 221 bool deleted = deleteDir(dataUpdatesDirName); 222 if (!deleted) { 223 LOG(WARNING) << "Deletion of install metadata " << dataUpdatesDirName 224 << " was not successful"; 225 } 226 227 // Delete the TZ data 228 LOG(INFO) << "Removing: " << dataCurrentDirName; 229 deleted = deleteDir(dataCurrentDirName); 230 if (!deleted) { 231 LOG(WARNING) << "Deletion of tzdata " << dataCurrentDirName << " was not successful"; 232 } 233 } 234 235 return 0; 236} 237