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platform_system_core/tzdatacheck/tzdatacheck.cpp

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/*
* 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;
}
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