tzdatacheck/tzdatacheck.cpp - third_party/android/platform/system/core - Git at Google

 /*
  * 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 file containing the distro version information.
 // See also libcore.tzdata.update2.TimeZoneDistro / libcore.tzdata.update2.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.update2.TimeZoneDistro / libcore.tzdata.update2.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.update2.TimeZoneDistro / libcore.tzdata.update2.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.update2.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, NOT_DIR };

 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 : NOT_DIR;
 }

 /*
  * 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;
     bool deleted = deleteDir(dataUpdatesDirName);
     if (!deleted) {
         LOG(WARNING) << "Deletion of install metadata " << dataUpdatesDirName
                 << " was not successful";
     }
 }

 /*
  * Deletes the timezone update distro directory.
  */
 static void deleteUpdateDistroDir(std::string& distroDirName) {
     LOG(INFO) << "Removing: " << distroDirName;
     bool deleted = deleteDir(distroDirName);
     if (!deleted) {
         LOG(WARNING) << "Deletion of distro dir " << distroDirName << " was not successful";
     }
 }

 /*
  * 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];

     // Check the distro directory exists. If it does not, exit quickly: nothing to do.
     std::string dataCurrentDirName(dataZoneInfoDir);
     dataCurrentDirName += "/current";
     int 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;
 }
	/*
	* 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 file containing the distro version information.
	// See also libcore.tzdata.update2.TimeZoneDistro / libcore.tzdata.update2.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.update2.TimeZoneDistro / libcore.tzdata.update2.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.update2.TimeZoneDistro / libcore.tzdata.update2.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.update2.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, NOT_DIR };

	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 : NOT_DIR;
	}

	/*
	* 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;
	bool deleted = deleteDir(dataUpdatesDirName);
	if (!deleted) {
	LOG(WARNING) << "Deletion of install metadata " << dataUpdatesDirName
	<< " was not successful";
	}
	}

	/*
	* Deletes the timezone update distro directory.
	*/
	static void deleteUpdateDistroDir(std::string& distroDirName) {
	LOG(INFO) << "Removing: " << distroDirName;
	bool deleted = deleteDir(distroDirName);
	if (!deleted) {
	LOG(WARNING) << "Deletion of distro dir " << distroDirName << " was not successful";
	}
	}

	/*
	* 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];

	// Check the distro directory exists. If it does not, exit quickly: nothing to do.
	std::string dataCurrentDirName(dataZoneInfoDir);
	dataCurrentDirName += "/current";
	int 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;
	}