|  | /* | 
|  | * Copyright (C) 2015 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. | 
|  | */ | 
|  |  | 
|  | #include <ctype.h> | 
|  | #include <errno.h> | 
|  | #include <ftw.h> | 
|  | #include <libgen.h> | 
|  | #include <stdarg.h> | 
|  | #include <stdio.h> | 
|  | #include <stdlib.h> | 
|  | #include <string.h> | 
|  | #include <unistd.h> | 
|  | #include <iostream> | 
|  | #include <memory> | 
|  | #include <string> | 
|  | #include <vector> | 
|  |  | 
|  | #include "android-base/logging.h" | 
|  |  | 
|  | // The name of the directory that holds a staged time zone update distro. If this exists it should | 
|  | // replace the one in CURRENT_DIR_NAME. | 
|  | // See also libcore.tzdata.update2.TimeZoneDistroInstaller. | 
|  | static const char* STAGED_DIR_NAME = "/staged"; | 
|  |  | 
|  | // The name of the directory that holds the (optional) installed time zone update distro. | 
|  | // See also libcore.tzdata.update2.TimeZoneDistroInstaller. | 
|  | static const char* CURRENT_DIR_NAME = "/current"; | 
|  |  | 
|  | // The name of a file in the staged dir that indicates the staged operation is an "uninstall". | 
|  | // See also libcore.tzdata.update2.TimeZoneDistroInstaller. | 
|  | static const char* UNINSTALL_TOMBSTONE_FILE_NAME = "/STAGED_UNINSTALL_TOMBSTONE"; | 
|  |  | 
|  | // The name of the file containing the distro version information. | 
|  | // See also libcore.tzdata.shared2.TimeZoneDistro / libcore.tzdata.shared2.DistroVersion. | 
|  | static const char* DISTRO_VERSION_FILENAME = "/distro_version"; | 
|  |  | 
|  | // distro_version is an ASCII file consisting of 17 bytes in the form: AAA.BBB|CCCCC|DDD | 
|  | // AAA.BBB is the major/minor version of the distro format (e.g. 001.001), | 
|  | // CCCCC is the rules version (e.g. 2016g) | 
|  | // DDD is the android revision for this rules version to allow for distro corrections (e.g. 001) | 
|  | // We only need the first 13 to determine if it is suitable for the device. | 
|  | static const int DISTRO_VERSION_LENGTH = 13; | 
|  |  | 
|  | // The major version of the distro format supported by this code as a null-terminated char[]. | 
|  | // See also libcore.tzdata.shared2.TimeZoneDistro / libcore.tzdata.shared2.DistroVersion. | 
|  | static const char SUPPORTED_DISTRO_MAJOR_VERSION[] = "001"; | 
|  |  | 
|  | // The length of the distro format major version excluding the \0 | 
|  | static const size_t SUPPORTED_DISTRO_MAJOR_VERSION_LEN = sizeof(SUPPORTED_DISTRO_MAJOR_VERSION) - 1; | 
|  |  | 
|  | // The minor version of the distro format supported by this code as a null-terminated char[]. | 
|  | // See also libcore.tzdata.shared2.TimeZoneDistro / libcore.tzdata.shared2.DistroVersion. | 
|  | static const char SUPPORTED_DISTRO_MINOR_VERSION[] = "001"; | 
|  |  | 
|  | // The length of the distro format minor version excluding the \0 | 
|  | static const size_t SUPPORTED_DISTRO_MINOR_VERSION_LEN = sizeof(SUPPORTED_DISTRO_MINOR_VERSION) - 1; | 
|  |  | 
|  | // The length of the distro format version. e.g. 001.001 | 
|  | static const size_t SUPPORTED_DISTRO_VERSION_LEN = | 
|  | SUPPORTED_DISTRO_MAJOR_VERSION_LEN + SUPPORTED_DISTRO_MINOR_VERSION_LEN + 1; | 
|  |  | 
|  | // The length of the IANA rules version bytes. e.g. 2016a | 
|  | static const size_t RULES_VERSION_LEN = 5; | 
|  |  | 
|  | // Distro version bytes are: AAA.BBB|CCCCC - the rules version is CCCCC | 
|  | static const size_t DISTRO_VERSION_RULES_IDX = 8; | 
|  |  | 
|  | // See also libcore.tzdata.shared2.TimeZoneDistro. | 
|  | static const char* TZDATA_FILENAME = "/tzdata"; | 
|  |  | 
|  | // tzdata file header (as much as we need for the version): | 
|  | // byte[11] tzdata_version  -- e.g. "tzdata2012f" | 
|  | static const int TZ_HEADER_LENGTH = 11; | 
|  |  | 
|  | static const char TZ_DATA_HEADER_PREFIX[] = "tzdata"; | 
|  | static const size_t TZ_DATA_HEADER_PREFIX_LEN = sizeof(TZ_DATA_HEADER_PREFIX) - 1; // exclude \0 | 
|  |  | 
|  | static void usage() { | 
|  | std::cerr << "Usage: tzdatacheck SYSTEM_TZ_DIR DATA_TZ_DIR\n" | 
|  | "\n" | 
|  | "Checks whether any timezone update distro in DATA_TZ_DIR is compatible with the\n" | 
|  | "current Android release and better than or the same as base system timezone rules in\n" | 
|  | "SYSTEM_TZ_DIR. If the timezone rules in SYSTEM_TZ_DIR are a higher version than the\n" | 
|  | "one in DATA_TZ_DIR the DATA_TZ_DIR is renamed and then deleted.\n"; | 
|  | exit(1); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Opens a file and fills buffer with the first byteCount bytes from the file. | 
|  | * If the file does not exist or cannot be opened or is too short then false is returned. | 
|  | * If the bytes were read successfully then true is returned. | 
|  | */ | 
|  | static bool readBytes(const std::string& fileName, char* buffer, size_t byteCount) { | 
|  | FILE* file = fopen(fileName.c_str(), "r"); | 
|  | if (file == nullptr) { | 
|  | if (errno != ENOENT) { | 
|  | PLOG(WARNING) << "Error opening file " << fileName; | 
|  | } | 
|  | return false; | 
|  | } | 
|  | size_t bytesRead = fread(buffer, 1, byteCount, file); | 
|  | fclose(file); | 
|  | if (bytesRead != byteCount) { | 
|  | LOG(WARNING) << fileName << " is too small. " << byteCount << " bytes required"; | 
|  | return false; | 
|  | } | 
|  | return true; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Checks the contents of headerBytes. Returns true if it is valid (starts with "tzdata"), false | 
|  | * otherwise. | 
|  | */ | 
|  | static bool checkValidTzDataHeader(const std::string& fileName, const char* headerBytes) { | 
|  | if (strncmp("tzdata", headerBytes, 6) != 0) { | 
|  | LOG(WARNING) << fileName << " does not start with the expected bytes (tzdata)"; | 
|  | return false; | 
|  | } | 
|  | return true; | 
|  | } | 
|  |  | 
|  | static bool checkDigits(const char* buffer, const size_t count, size_t* i) { | 
|  | for (size_t j = 0; j < count; j++) { | 
|  | char toCheck = buffer[(*i)++]; | 
|  | if (!isdigit(toCheck)) { | 
|  | return false; | 
|  | } | 
|  | } | 
|  | return true; | 
|  | } | 
|  |  | 
|  | static bool checkValidDistroVersion(const char* buffer) { | 
|  | // See DISTRO_VERSION_LENGTH comments above for a description of the format. | 
|  | size_t i = 0; | 
|  | if (!checkDigits(buffer, 3, &i)) { | 
|  | return false; | 
|  | } | 
|  | if (buffer[i++] != '.') { | 
|  | return false; | 
|  | } | 
|  | if (!checkDigits(buffer, 3, &i)) { | 
|  | return false; | 
|  | } | 
|  | if (buffer[i++] != '|') { | 
|  | return false; | 
|  | } | 
|  | if (!checkDigits(buffer, 4, &i)) { | 
|  | return false; | 
|  | } | 
|  | // Ignore the last character. It is assumed to be a letter but we don't check because it's not | 
|  | // obvious what would happen at 'z'. | 
|  | return true; | 
|  | } | 
|  |  | 
|  | /* Return the parent directory of dirName. */ | 
|  | static std::string getParentDir(const std::string& dirName) { | 
|  | std::unique_ptr<char> mutable_dirname(strdup(dirName.c_str())); | 
|  | return dirname(mutable_dirname.get()); | 
|  | } | 
|  |  | 
|  | /* Deletes a single file, symlink or directory. Called from nftw(). */ | 
|  | static int deleteFn(const char* fpath, const struct stat*, int typeflag, struct FTW*) { | 
|  | LOG(DEBUG) << "Inspecting " << fpath; | 
|  | switch (typeflag) { | 
|  | case FTW_F: | 
|  | case FTW_SL: | 
|  | LOG(DEBUG) << "Unlinking " << fpath; | 
|  | if (unlink(fpath)) { | 
|  | PLOG(WARNING) << "Failed to unlink file/symlink " << fpath; | 
|  | } | 
|  | break; | 
|  | case FTW_D: | 
|  | case FTW_DP: | 
|  | LOG(DEBUG) << "Removing dir " << fpath; | 
|  | if (rmdir(fpath)) { | 
|  | PLOG(WARNING) << "Failed to remove dir " << fpath; | 
|  | } | 
|  | break; | 
|  | default: | 
|  | LOG(WARNING) << "Unsupported file type " << fpath << ": " << typeflag; | 
|  | break; | 
|  | } | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | enum PathStatus { ERR, NONE, IS_DIR, IS_REG, UNKNOWN }; | 
|  |  | 
|  | static PathStatus checkPath(const std::string& path) { | 
|  | struct stat buf; | 
|  | if (stat(path.c_str(), &buf) != 0) { | 
|  | if (errno != ENOENT) { | 
|  | PLOG(WARNING) << "Unable to stat " << path; | 
|  | return ERR; | 
|  | } | 
|  | return NONE; | 
|  | } | 
|  | return S_ISDIR(buf.st_mode) ? IS_DIR : S_ISREG(buf.st_mode) ? IS_REG : UNKNOWN; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Deletes fileToDelete and returns true if it is successful. If fileToDelete is not a file or | 
|  | * cannot be accessed this method returns false. | 
|  | */ | 
|  | static bool deleteFile(const std::string& fileToDelete) { | 
|  | // Check whether the file exists. | 
|  | PathStatus pathStatus = checkPath(fileToDelete); | 
|  | if (pathStatus == NONE) { | 
|  | LOG(INFO) << "Path " << fileToDelete << " does not exist"; | 
|  | return true; | 
|  | } | 
|  | if (pathStatus != IS_REG) { | 
|  | LOG(WARNING) << "Path " << fileToDelete << " failed to stat() or is not a file."; | 
|  | return false; | 
|  | } | 
|  |  | 
|  | // Attempt the deletion. | 
|  | int rc = unlink(fileToDelete.c_str()); | 
|  | if (rc != 0) { | 
|  | PLOG(WARNING) << "unlink() failed for " << fileToDelete; | 
|  | } | 
|  | return rc == 0; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Deletes dirToDelete and returns true if it is successful in removing or moving the directory out | 
|  | * of the way. If dirToDelete does not exist this function does nothing and returns true. If | 
|  | * dirToDelete is not a directory or cannot be accessed this method returns false. | 
|  | * | 
|  | * During deletion, this function first renames the directory to a temporary name. If the temporary | 
|  | * directory cannot be created, or the directory cannot be renamed, false is returned. After the | 
|  | * rename, deletion of files and subdirs beneath the directory is performed on a "best effort" | 
|  | * basis. Symlinks beneath the directory are not followed. | 
|  | */ | 
|  | static bool deleteDir(const std::string& dirToDelete) { | 
|  | // Check whether the dir exists. | 
|  | int pathStatus = checkPath(dirToDelete); | 
|  | if (pathStatus == NONE) { | 
|  | LOG(INFO) << "Path " << dirToDelete << " does not exist"; | 
|  | return true; | 
|  | } | 
|  | if (pathStatus != IS_DIR) { | 
|  | LOG(WARNING) << "Path " << dirToDelete << " failed to stat() or is not a directory."; | 
|  | return false; | 
|  | } | 
|  |  | 
|  | // First, rename dirToDelete. | 
|  |  | 
|  | std::string tempDirNameTemplate = getParentDir(dirToDelete); | 
|  | tempDirNameTemplate += "/tempXXXXXX"; | 
|  |  | 
|  | // Create an empty directory with the temporary name. For this we need a non-const char*. | 
|  | std::vector<char> tempDirName(tempDirNameTemplate.length() + 1); | 
|  | strcpy(&tempDirName[0], tempDirNameTemplate.c_str()); | 
|  | if (mkdtemp(&tempDirName[0]) == nullptr) { | 
|  | PLOG(WARNING) << "Unable to create a temporary directory: " << tempDirNameTemplate; | 
|  | return false; | 
|  | } | 
|  |  | 
|  | // Rename dirToDelete to tempDirName (replacing the empty tempDirName directory created above). | 
|  | int rc = rename(dirToDelete.c_str(), &tempDirName[0]); | 
|  | if (rc == -1) { | 
|  | PLOG(WARNING) << "Unable to rename directory from " << dirToDelete << " to " | 
|  | << &tempDirName[0]; | 
|  | return false; | 
|  | } | 
|  |  | 
|  | // Recursively delete contents of tempDirName. | 
|  |  | 
|  | rc = nftw(&tempDirName[0], deleteFn, 10 /* openFiles */, | 
|  | FTW_DEPTH | FTW_MOUNT | FTW_PHYS); | 
|  | if (rc == -1) { | 
|  | LOG(INFO) << "Could not delete directory: " << &tempDirName[0]; | 
|  | } | 
|  | return true; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Deletes the ConfigInstaller metadata directory. | 
|  | * TODO(nfuller). http://b/31008728 Remove this when ConfigInstaller is no longer used. | 
|  | */ | 
|  | static void deleteConfigUpdaterMetadataDir(const char* dataZoneInfoDir) { | 
|  | // Delete the update metadata | 
|  | std::string dataUpdatesDirName(dataZoneInfoDir); | 
|  | dataUpdatesDirName += "/updates"; | 
|  | LOG(INFO) << "Removing: " << dataUpdatesDirName; | 
|  | if (!deleteDir(dataUpdatesDirName)) { | 
|  | LOG(WARNING) << "Deletion of install metadata " << dataUpdatesDirName | 
|  | << " was not successful"; | 
|  | } | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Deletes the timezone update distro directory. | 
|  | */ | 
|  | static void deleteUpdateDistroDir(const std::string& distroDirName) { | 
|  | LOG(INFO) << "Removing: " << distroDirName; | 
|  | if (!deleteDir(distroDirName)) { | 
|  | LOG(WARNING) << "Deletion of distro dir " << distroDirName << " was not successful"; | 
|  | } | 
|  | } | 
|  |  | 
|  | static void handleStagedUninstall(const std::string& dataStagedDirName, | 
|  | const std::string& dataCurrentDirName, | 
|  | const PathStatus dataCurrentDirStatus) { | 
|  | LOG(INFO) << "Staged operation is an uninstall."; | 
|  |  | 
|  | // Delete the current install directory. | 
|  | switch (dataCurrentDirStatus) { | 
|  | case NONE: | 
|  | // This is unexpected: No uninstall should be staged if there is nothing to | 
|  | // uninstall. Carry on anyway. | 
|  | LOG(WARNING) << "No current install to delete."; | 
|  | break; | 
|  | case IS_DIR: | 
|  | // This is normal. Delete the current install dir. | 
|  | if (!deleteDir(dataCurrentDirName)) { | 
|  | LOG(WARNING) << "Deletion of current distro " << dataCurrentDirName | 
|  | << " was not successful"; | 
|  | // If this happens we don't know whether we were able to delete or not. We don't | 
|  | // delete the staged operation so it will be retried next boot unless overridden. | 
|  | return; | 
|  | } | 
|  | break; | 
|  | case IS_REG: | 
|  | default: | 
|  | // This is unexpected: We can try to delete the unexpected file and carry on. | 
|  | LOG(WARNING) << "Current distro dir " << dataCurrentDirName | 
|  | << " is not actually a directory. Attempting deletion."; | 
|  | if (!deleteFile(dataCurrentDirName)) { | 
|  | LOG(WARNING) << "Could not delete " << dataCurrentDirName; | 
|  | return; | 
|  | } | 
|  | break; | 
|  | } | 
|  |  | 
|  | // Delete the staged uninstall dir. | 
|  | if (!deleteDir(dataStagedDirName)) { | 
|  | LOG(WARNING) << "Deletion of current distro " << dataCurrentDirName | 
|  | << " was not successful"; | 
|  | // If this happens we don't know whether we were able to delete the staged operation | 
|  | // or not. | 
|  | return; | 
|  | } | 
|  | LOG(INFO) << "Staged uninstall complete."; | 
|  | } | 
|  |  | 
|  | static void handleStagedInstall(const std::string& dataStagedDirName, | 
|  | const std::string& dataCurrentDirName, | 
|  | const PathStatus dataCurrentDirStatus) { | 
|  | LOG(INFO) << "Staged operation is an install."; | 
|  |  | 
|  | switch (dataCurrentDirStatus) { | 
|  | case NONE: | 
|  | // This is expected: This is the first install. | 
|  | LOG(INFO) << "No current install to replace."; | 
|  | break; | 
|  | case IS_DIR: | 
|  | // This is expected: We are replacing an existing install. | 
|  | // Delete the current dir so we can replace it. | 
|  | if (!deleteDir(dataCurrentDirName)) { | 
|  | LOG(WARNING) << "Deletion of current distro " << dataCurrentDirName | 
|  | << " was not successful"; | 
|  | // If this happens, we cannot proceed. | 
|  | return; | 
|  | } | 
|  | break; | 
|  | case IS_REG: | 
|  | default: | 
|  | // This is unexpected: We can try to delete the unexpected file and carry on. | 
|  | LOG(WARNING) << "Current distro dir " << dataCurrentDirName | 
|  | << " is not actually a directory. Attempting deletion."; | 
|  | if (!deleteFile(dataCurrentDirName)) { | 
|  | LOG(WARNING) << "Could not delete " << dataCurrentDirName; | 
|  | return; | 
|  | } | 
|  | break; | 
|  | } | 
|  |  | 
|  | // Move the staged dir so it is the new current dir, completing the install. | 
|  | LOG(INFO) << "Moving " << dataStagedDirName << " to " << dataCurrentDirName; | 
|  | int rc = rename(dataStagedDirName.c_str(), dataCurrentDirName.c_str()); | 
|  | if (rc == -1) { | 
|  | PLOG(WARNING) << "Unable to rename directory from " << dataStagedDirName << " to " | 
|  | << &dataCurrentDirName[0]; | 
|  | return; | 
|  | } | 
|  |  | 
|  | LOG(INFO) << "Staged install complete."; | 
|  | } | 
|  | /* | 
|  | * Process a staged operation if there is one. | 
|  | */ | 
|  | static void processStagedOperation(const std::string& dataStagedDirName, | 
|  | const std::string& dataCurrentDirName) { | 
|  | PathStatus dataStagedDirStatus = checkPath(dataStagedDirName); | 
|  |  | 
|  | // Exit early for the common case. | 
|  | if (dataStagedDirStatus == NONE) { | 
|  | LOG(DEBUG) << "No staged time zone operation."; | 
|  | return; | 
|  | } | 
|  |  | 
|  | // Check known directory names are in a good starting state. | 
|  | if (dataStagedDirStatus != IS_DIR) { | 
|  | LOG(WARNING) << "Staged distro dir " << dataStagedDirName | 
|  | << " could not be accessed or is not a directory." | 
|  | << " stagedDirStatus=" << dataStagedDirStatus; | 
|  | return; | 
|  | } | 
|  |  | 
|  | // dataStagedDirStatus == IS_DIR. | 
|  |  | 
|  | // Work out whether there is anything currently installed. | 
|  | PathStatus dataCurrentDirStatus = checkPath(dataCurrentDirName); | 
|  | if (dataCurrentDirStatus == ERR) { | 
|  | LOG(WARNING) << "Current install dir " << dataCurrentDirName << " could not be accessed" | 
|  | << " dataCurrentDirStatus=" << dataCurrentDirStatus; | 
|  | return; | 
|  | } | 
|  |  | 
|  | // We must perform the staged operation. | 
|  |  | 
|  | // Check to see if the staged directory contains an uninstall or an install operation. | 
|  | std::string uninstallTombStoneFile(dataStagedDirName); | 
|  | uninstallTombStoneFile += UNINSTALL_TOMBSTONE_FILE_NAME; | 
|  | int uninstallTombStoneFileStatus = checkPath(uninstallTombStoneFile); | 
|  | if (uninstallTombStoneFileStatus != IS_REG && uninstallTombStoneFileStatus != NONE) { | 
|  | // Error case. | 
|  | LOG(WARNING) << "Unable to determine if the staged operation is an uninstall."; | 
|  | return; | 
|  | } | 
|  | if (uninstallTombStoneFileStatus == IS_REG) { | 
|  | handleStagedUninstall(dataStagedDirName, dataCurrentDirName, dataCurrentDirStatus); | 
|  | } else { | 
|  | // uninstallTombStoneFileStatus == NONE meaning this is a staged install. | 
|  | handleStagedInstall(dataStagedDirName, dataCurrentDirName, dataCurrentDirStatus); | 
|  | } | 
|  | } | 
|  |  | 
|  | /* | 
|  | * After a platform update it is likely that timezone data found on the system partition will be | 
|  | * newer than the version found in the data partition. This tool detects this case and removes the | 
|  | * version in /data. | 
|  | * | 
|  | * Note: This code is related to code in com.android.server.updates.TzDataInstallReceiver. The | 
|  | * paths for the metadata and current timezone data must match. | 
|  | * | 
|  | * Typically on device the two args will be: | 
|  | *   /system/usr/share/zoneinfo /data/misc/zoneinfo | 
|  | * | 
|  | * See usage() for usage notes. | 
|  | */ | 
|  | int main(int argc, char* argv[]) { | 
|  | if (argc != 3) { | 
|  | usage(); | 
|  | return 1; | 
|  | } | 
|  |  | 
|  | const char* systemZoneInfoDir = argv[1]; | 
|  | const char* dataZoneInfoDir = argv[2]; | 
|  |  | 
|  | std::string dataStagedDirName(dataZoneInfoDir); | 
|  | dataStagedDirName += STAGED_DIR_NAME; | 
|  |  | 
|  | std::string dataCurrentDirName(dataZoneInfoDir); | 
|  | dataCurrentDirName += CURRENT_DIR_NAME; | 
|  |  | 
|  | // Check for an process any staged operation. | 
|  | // If the staged operation could not be handled we still have to validate the current installed | 
|  | // directory so we do not check for errors and do not quit early. | 
|  | processStagedOperation(dataStagedDirName, dataCurrentDirName); | 
|  |  | 
|  | // Check the distro directory exists. If it does not, exit quickly: nothing to do. | 
|  | PathStatus dataCurrentDirStatus = checkPath(dataCurrentDirName); | 
|  | if (dataCurrentDirStatus == NONE) { | 
|  | LOG(INFO) << "timezone distro dir " << dataCurrentDirName | 
|  | << " does not exist. No action required."; | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | // If the distro directory path is not a directory or we can't stat() the path, exit with a | 
|  | // warning: either there's a problem accessing storage or the world is not as it should be; | 
|  | // nothing to do. | 
|  | if (dataCurrentDirStatus != IS_DIR) { | 
|  | LOG(WARNING) << "Current distro dir " << dataCurrentDirName | 
|  | << " could not be accessed or is not a directory. result=" << dataCurrentDirStatus; | 
|  | return 2; | 
|  | } | 
|  |  | 
|  | // Check the installed distro version. | 
|  | std::string distroVersionFileName(dataCurrentDirName); | 
|  | distroVersionFileName += DISTRO_VERSION_FILENAME; | 
|  | std::vector<char> distroVersion; | 
|  | distroVersion.reserve(DISTRO_VERSION_LENGTH); | 
|  | bool distroVersionReadOk = | 
|  | readBytes(distroVersionFileName, distroVersion.data(), DISTRO_VERSION_LENGTH); | 
|  | if (!distroVersionReadOk) { | 
|  | LOG(WARNING) << "distro version file " << distroVersionFileName | 
|  | << " does not exist or is too short. Deleting distro dir."; | 
|  | // Implies the contents of the data partition is corrupt in some way. Try to clean up. | 
|  | deleteConfigUpdaterMetadataDir(dataZoneInfoDir); | 
|  | deleteUpdateDistroDir(dataCurrentDirName); | 
|  | return 3; | 
|  | } | 
|  |  | 
|  | if (!checkValidDistroVersion(distroVersion.data())) { | 
|  | LOG(WARNING) << "distro version file " << distroVersionFileName | 
|  | << " is not valid. Deleting distro dir."; | 
|  | // Implies the contents of the data partition is corrupt in some way. Try to clean up. | 
|  | deleteConfigUpdaterMetadataDir(dataZoneInfoDir); | 
|  | deleteUpdateDistroDir(dataCurrentDirName); | 
|  | return 4; | 
|  | } | 
|  |  | 
|  | std::string actualDistroVersion = | 
|  | std::string(distroVersion.data(), SUPPORTED_DISTRO_VERSION_LEN); | 
|  | // Check the first 3 bytes of the distro version: these are the major version (e.g. 001). | 
|  | // It must match the one we support exactly to be ok. | 
|  | if (strncmp( | 
|  | &distroVersion[0], | 
|  | SUPPORTED_DISTRO_MAJOR_VERSION, | 
|  | SUPPORTED_DISTRO_MAJOR_VERSION_LEN) != 0) { | 
|  |  | 
|  | LOG(INFO) << "distro version file " << distroVersionFileName | 
|  | << " major version is not the required version " << SUPPORTED_DISTRO_MAJOR_VERSION | 
|  | << ", was \"" << actualDistroVersion << "\". Deleting distro dir."; | 
|  | // This implies there has been an OTA and the installed distro is not compatible with the | 
|  | // new version of Android. Remove the installed distro. | 
|  | deleteConfigUpdaterMetadataDir(dataZoneInfoDir); | 
|  | deleteUpdateDistroDir(dataCurrentDirName); | 
|  | return 5; | 
|  | } | 
|  |  | 
|  | // Check the last 3 bytes of the distro version: these are the minor version (e.g. 001). | 
|  | // If the version in the distro is < the minor version required by this device it cannot be | 
|  | // used. | 
|  | if (strncmp( | 
|  | &distroVersion[4], | 
|  | SUPPORTED_DISTRO_MINOR_VERSION, | 
|  | SUPPORTED_DISTRO_MINOR_VERSION_LEN) < 0) { | 
|  |  | 
|  | LOG(INFO) << "distro version file " << distroVersionFileName | 
|  | << " minor version is not the required version " << SUPPORTED_DISTRO_MINOR_VERSION | 
|  | << ", was \"" << actualDistroVersion << "\". Deleting distro dir."; | 
|  | // This implies there has been an OTA and the installed distro is not compatible with the | 
|  | // new version of Android. Remove the installed distro. | 
|  | deleteConfigUpdaterMetadataDir(dataZoneInfoDir); | 
|  | deleteUpdateDistroDir(dataCurrentDirName); | 
|  | return 5; | 
|  | } | 
|  |  | 
|  | // Read the system rules version out of the /system tzdata file. | 
|  | std::string systemTzDataFileName(systemZoneInfoDir); | 
|  | systemTzDataFileName += TZDATA_FILENAME; | 
|  | std::vector<char> systemTzDataHeader; | 
|  | systemTzDataHeader.reserve(TZ_HEADER_LENGTH); | 
|  | bool systemFileExists = | 
|  | readBytes(systemTzDataFileName, systemTzDataHeader.data(), TZ_HEADER_LENGTH); | 
|  | if (!systemFileExists) { | 
|  | // Implies the contents of the system partition is corrupt in some way. Nothing we can do. | 
|  | LOG(WARNING) << systemTzDataFileName << " does not exist or could not be opened"; | 
|  | return 6; | 
|  | } | 
|  | if (!checkValidTzDataHeader(systemTzDataFileName, systemTzDataHeader.data())) { | 
|  | // Implies the contents of the system partition is corrupt in some way. Nothing we can do. | 
|  | LOG(WARNING) << systemTzDataFileName << " does not have a valid header."; | 
|  | return 7; | 
|  | } | 
|  |  | 
|  | // Compare the distro rules version against the system rules version. | 
|  | if (strncmp( | 
|  | &systemTzDataHeader[TZ_DATA_HEADER_PREFIX_LEN], | 
|  | &distroVersion[DISTRO_VERSION_RULES_IDX], | 
|  | RULES_VERSION_LEN) <= 0) { | 
|  | LOG(INFO) << "Found an installed distro but it is valid. No action taken."; | 
|  | // Implies there is an installed update, but it is good. | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | // Implies there has been an OTA and the system version of the timezone rules is now newer | 
|  | // than the version installed in /data. Remove the installed distro. | 
|  | LOG(INFO) << "timezone distro in " << dataCurrentDirName << " is older than data in " | 
|  | << systemTzDataFileName << "; fixing..."; | 
|  |  | 
|  | deleteConfigUpdaterMetadataDir(dataZoneInfoDir); | 
|  | deleteUpdateDistroDir(dataCurrentDirName); | 
|  | return 0; | 
|  | } |