distro/installer/src/main/com/android/timezone/distro/installer/TimeZoneDistroInstaller.java - platform/system/timezone - 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.
  */
 package com.android.timezone.distro.installer;

 import com.android.timezone.distro.DistroException;
 import com.android.timezone.distro.DistroVersion;
 import com.android.timezone.distro.FileUtils;
 import com.android.timezone.distro.StagedDistroOperation;
 import com.android.timezone.distro.TimeZoneDistro;

 import android.annotation.IntDef;
 import android.util.Slog;

 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import libcore.util.TimeZoneFinder;
 import libcore.util.ZoneInfoDB;

 /**
  * A distro-validation / extraction class. Separate from the services code that uses it for easier
  * testing. This class is not thread-safe: callers are expected to handle mutual exclusion.
  */
 public class TimeZoneDistroInstaller {

     @Retention(RetentionPolicy.SOURCE)
     @IntDef(prefix = { "INSTALL_" }, value = {
             INSTALL_SUCCESS,
             INSTALL_FAIL_BAD_DISTRO_STRUCTURE,
             INSTALL_FAIL_BAD_DISTRO_FORMAT_VERSION,
             INSTALL_FAIL_RULES_TOO_OLD,
             INSTALL_FAIL_VALIDATION_ERROR,
     })
     private @interface InstallResultType {}

     /** {@link #stageInstallWithErrorCode(TimeZoneDistro)} result code: Success. */
     public final static int INSTALL_SUCCESS = 0;

     /** {@link #stageInstallWithErrorCode(TimeZoneDistro)} result code: Distro corrupt. */
     public final static int INSTALL_FAIL_BAD_DISTRO_STRUCTURE = 1;

     /**
      * {@link #stageInstallWithErrorCode(TimeZoneDistro)} result code: Distro version incompatible.
      */
     public final static int INSTALL_FAIL_BAD_DISTRO_FORMAT_VERSION = 2;

     /**
      * {@link #stageInstallWithErrorCode(TimeZoneDistro)} result code: Distro rules too old for
      * device.
      */
     public final static int INSTALL_FAIL_RULES_TOO_OLD = 3;

     /**
      * {@link #stageInstallWithErrorCode(TimeZoneDistro)} result code: Distro content failed
      * validation.
      */
     public final static int INSTALL_FAIL_VALIDATION_ERROR = 4;

     @Retention(RetentionPolicy.SOURCE)
     @IntDef(prefix = { "UNINSTALL_" }, value = {
             UNINSTALL_SUCCESS,
             UNINSTALL_NOTHING_INSTALLED,
             UNINSTALL_FAIL,
     })
     private @interface UninstallResultType {}

     /**
      * {@link #stageUninstall()} result code: An uninstall has been successfully staged.
      */
     public final static int UNINSTALL_SUCCESS = 0;

     /**
      * {@link #stageUninstall()} result code: Nothing was installed that required an uninstall to be
      * staged.
      */
     public final static int UNINSTALL_NOTHING_INSTALLED = 1;

     /**
      * {@link #stageUninstall()} result code: The uninstall could not be staged.
      */
     public final static int UNINSTALL_FAIL = 2;

     // This constant must match one in system/timezone/tzdatacheck/tzdatacheck.cpp.
     private static final String STAGED_TZ_DATA_DIR_NAME = "staged";
     // This constant must match one in system/timezone/tzdatacheck/tzdatacheck.cpp.
     private static final String CURRENT_TZ_DATA_DIR_NAME = "current";
     private static final String WORKING_DIR_NAME = "working";
     private static final String OLD_TZ_DATA_DIR_NAME = "old";

     /**
      * The name of the file in the staged directory used to indicate a staged uninstallation.
      */
     // This constant must match one in system/timezone/tzdatacheck/tzdatacheck.cpp.
     // VisibleForTesting.
     public static final String UNINSTALL_TOMBSTONE_FILE_NAME = "STAGED_UNINSTALL_TOMBSTONE";

     private final String logTag;
     private final File systemTzDataFile;
     private final File oldStagedDataDir;
     private final File stagedTzDataDir;
     private final File currentTzDataDir;
     private final File workingDir;

     public TimeZoneDistroInstaller(String logTag, File systemTzDataFile, File installDir) {
         this.logTag = logTag;
         this.systemTzDataFile = systemTzDataFile;
         oldStagedDataDir = new File(installDir, OLD_TZ_DATA_DIR_NAME);
         stagedTzDataDir = new File(installDir, STAGED_TZ_DATA_DIR_NAME);
         currentTzDataDir = new File(installDir, CURRENT_TZ_DATA_DIR_NAME);
         workingDir = new File(installDir, WORKING_DIR_NAME);
     }

     // VisibleForTesting
     File getOldStagedDataDir() {
         return oldStagedDataDir;
     }

     // VisibleForTesting
     File getStagedTzDataDir() {
         return stagedTzDataDir;
     }

     // VisibleForTesting
     File getCurrentTzDataDir() {
         return currentTzDataDir;
     }

     // VisibleForTesting
     File getWorkingDir() {
         return workingDir;
     }

     /**
      * Stage an install of the supplied content, to be installed the next time the device boots.
      *
      * <p>Errors during unpacking or staging will throw an {@link IOException}.
      * Returns {@link #INSTALL_SUCCESS} on success, or one of the failure codes.
      */
     public @InstallResultType int stageInstallWithErrorCode(TimeZoneDistro distro)
             throws IOException {
         if (oldStagedDataDir.exists()) {
             FileUtils.deleteRecursive(oldStagedDataDir);
         }
         if (workingDir.exists()) {
             FileUtils.deleteRecursive(workingDir);
         }

         Slog.i(logTag, "Unpacking / verifying time zone update");
         try {
             unpackDistro(distro, workingDir);

             DistroVersion distroVersion;
             try {
                 distroVersion = readDistroVersion(workingDir);
             } catch (DistroException e) {
                 Slog.i(logTag, "Invalid distro version: " + e.getMessage());
                 return INSTALL_FAIL_BAD_DISTRO_STRUCTURE;
             }
             if (distroVersion == null) {
                 Slog.i(logTag, "Update not applied: Distro version could not be loaded");
                 return INSTALL_FAIL_BAD_DISTRO_STRUCTURE;
             }
             if (!DistroVersion.isCompatibleWithThisDevice(distroVersion)) {
                 Slog.i(logTag, "Update not applied: Distro format version check failed: "
                         + distroVersion);
                 return INSTALL_FAIL_BAD_DISTRO_FORMAT_VERSION;
             }

             if (!checkDistroDataFilesExist(workingDir)) {
                 Slog.i(logTag, "Update not applied: Distro is missing required data file(s)");
                 return INSTALL_FAIL_BAD_DISTRO_STRUCTURE;
             }

             if (!checkDistroRulesNewerThanSystem(systemTzDataFile, distroVersion)) {
                 Slog.i(logTag, "Update not applied: Distro rules version check failed");
                 return INSTALL_FAIL_RULES_TOO_OLD;
             }

             // Validate the tzdata file.
             File zoneInfoFile = new File(workingDir, TimeZoneDistro.TZDATA_FILE_NAME);
             ZoneInfoDB.TzData tzData = ZoneInfoDB.TzData.loadTzData(zoneInfoFile.getPath());
             if (tzData == null) {
                 Slog.i(logTag, "Update not applied: " + zoneInfoFile + " could not be loaded");
                 return INSTALL_FAIL_VALIDATION_ERROR;
             }
             try {
                 tzData.validate();
             } catch (IOException e) {
                 Slog.i(logTag, "Update not applied: " + zoneInfoFile + " failed validation", e);
                 return INSTALL_FAIL_VALIDATION_ERROR;
             } finally {
                 tzData.close();
             }

             // Validate the tzlookup.xml file.
             File tzLookupFile = new File(workingDir, TimeZoneDistro.TZLOOKUP_FILE_NAME);
             if (!tzLookupFile.exists()) {
                 Slog.i(logTag, "Update not applied: " + tzLookupFile + " does not exist");
                 return INSTALL_FAIL_BAD_DISTRO_STRUCTURE;
             }
             try {
                 TimeZoneFinder timeZoneFinder =
                         TimeZoneFinder.createInstance(tzLookupFile.getPath());
                 timeZoneFinder.validate();
             } catch (IOException e) {
                 Slog.i(logTag, "Update not applied: " + tzLookupFile + " failed validation", e);
                 return INSTALL_FAIL_VALIDATION_ERROR;
             }

             // TODO(nfuller): Add validity checks for ICU data / canarying before applying.
             // http://b/64016752

             Slog.i(logTag, "Applying time zone update");
             FileUtils.makeDirectoryWorldAccessible(workingDir);

             // Check if there is already a staged install or uninstall and remove it if there is.
             if (!stagedTzDataDir.exists()) {
                 Slog.i(logTag, "Nothing to unstage at " + stagedTzDataDir);
             } else {
                 Slog.i(logTag, "Moving " + stagedTzDataDir + " to " + oldStagedDataDir);
                 // Move stagedTzDataDir out of the way in one operation so we can't partially delete
                 // the contents.
                 FileUtils.rename(stagedTzDataDir, oldStagedDataDir);
             }

             // Move the workingDir to be the new staged directory.
             Slog.i(logTag, "Moving " + workingDir + " to " + stagedTzDataDir);
             FileUtils.rename(workingDir, stagedTzDataDir);
             Slog.i(logTag, "Install staged: " + stagedTzDataDir + " successfully created");
             return INSTALL_SUCCESS;
         } finally {
             deleteBestEffort(oldStagedDataDir);
             deleteBestEffort(workingDir);
         }
     }

     /**
      * Stage an uninstall of the current timezone update in /data which, on reboot, will return the
      * device to using data from /system. If there was something else already staged it will be
      * removed by this call.
      *
      * Returns {@link #UNINSTALL_SUCCESS} if staging the uninstallation was
      * successful and reboot will be required. Returns {@link #UNINSTALL_NOTHING_INSTALLED} if
      * there was nothing installed in /data that required an uninstall to be staged, anything that
      * was staged will have been removed and therefore no reboot is required.
      *
      * <p>Errors encountered during uninstallation will throw an {@link IOException}.
      */
     public @UninstallResultType int stageUninstall() throws IOException {
         Slog.i(logTag, "Uninstalling time zone update");

         if (oldStagedDataDir.exists()) {
             // If we can't remove this, an exception is thrown and we don't continue.
             FileUtils.deleteRecursive(oldStagedDataDir);
         }
         if (workingDir.exists()) {
             FileUtils.deleteRecursive(workingDir);
         }

         try {
             // Check if there is already an install or uninstall staged and remove it.
             if (!stagedTzDataDir.exists()) {
                 Slog.i(logTag, "Nothing to unstage at " + stagedTzDataDir);
             } else {
                 Slog.i(logTag, "Moving " + stagedTzDataDir + " to " + oldStagedDataDir);
                 // Move stagedTzDataDir out of the way in one operation so we can't partially delete
                 // the contents.
                 FileUtils.rename(stagedTzDataDir, oldStagedDataDir);
             }

             // If there's nothing actually installed, there's nothing to uninstall so no need to
             // stage anything.
             if (!currentTzDataDir.exists()) {
                 Slog.i(logTag, "Nothing to uninstall at " + currentTzDataDir);
                 return UNINSTALL_NOTHING_INSTALLED;
             }

             // Stage an uninstall in workingDir.
             FileUtils.ensureDirectoriesExist(workingDir, true /* makeWorldReadable */);
             FileUtils.createEmptyFile(new File(workingDir, UNINSTALL_TOMBSTONE_FILE_NAME));

             // Move the workingDir to be the new staged directory.
             Slog.i(logTag, "Moving " + workingDir + " to " + stagedTzDataDir);
             FileUtils.rename(workingDir, stagedTzDataDir);
             Slog.i(logTag, "Uninstall staged: " + stagedTzDataDir + " successfully created");

             return UNINSTALL_SUCCESS;
         } finally {
             deleteBestEffort(oldStagedDataDir);
             deleteBestEffort(workingDir);
         }
     }

     /**
      * Reads the currently installed distro version. Returns {@code null} if there is no distro
      * installed.
      *
      * @throws IOException if there was a problem reading data from /data
      * @throws DistroException if there was a problem with the installed distro format/structure
      */
     public DistroVersion getInstalledDistroVersion() throws DistroException, IOException {
         if (!currentTzDataDir.exists()) {
             return null;
         }
         return readDistroVersion(currentTzDataDir);
     }

     /**
      * Reads information about any currently staged distro operation. Returns {@code null} if there
      * is no distro operation staged.
      *
      * @throws IOException if there was a problem reading data from /data
      * @throws DistroException if there was a problem with the staged distro format/structure
      */
     public StagedDistroOperation getStagedDistroOperation() throws DistroException, IOException {
         if (!stagedTzDataDir.exists()) {
             return null;
         }
         if (new File(stagedTzDataDir, UNINSTALL_TOMBSTONE_FILE_NAME).exists()) {
             return StagedDistroOperation.uninstall();
         } else {
             return StagedDistroOperation.install(readDistroVersion(stagedTzDataDir));
         }
     }

     /**
      * Reads the timezone rules version present in /system. i.e. the version that would be present
      * after a factory reset.
      *
      * @throws IOException if there was a problem reading data
      */
     public String getSystemRulesVersion() throws IOException {
         return readSystemRulesVersion(systemTzDataFile);
     }

     private void deleteBestEffort(File dir) {
         if (dir.exists()) {
             Slog.i(logTag, "Deleting " + dir);
             try {
                 FileUtils.deleteRecursive(dir);
             } catch (IOException e) {
                 // Logged but otherwise ignored.
                 Slog.w(logTag, "Unable to delete " + dir, e);
             }
         }
     }

     private void unpackDistro(TimeZoneDistro distro, File targetDir) throws IOException {
         Slog.i(logTag, "Unpacking update content to: " + targetDir);
         distro.extractTo(targetDir);
     }

     private boolean checkDistroDataFilesExist(File unpackedContentDir) throws IOException {
         Slog.i(logTag, "Verifying distro contents");
         return FileUtils.filesExist(unpackedContentDir,
                 TimeZoneDistro.TZDATA_FILE_NAME,
                 TimeZoneDistro.ICU_DATA_FILE_NAME);
     }

     private DistroVersion readDistroVersion(File distroDir) throws DistroException, IOException {
         Slog.d(logTag, "Reading distro format version: " + distroDir);
         File distroVersionFile = new File(distroDir, TimeZoneDistro.DISTRO_VERSION_FILE_NAME);
         if (!distroVersionFile.exists()) {
             throw new DistroException("No distro version file found: " + distroVersionFile);
         }
         byte[] versionBytes =
                 FileUtils.readBytes(distroVersionFile, DistroVersion.DISTRO_VERSION_FILE_LENGTH);
         return DistroVersion.fromBytes(versionBytes);
     }

     /**
      * Returns true if the the distro IANA rules version is >= system IANA rules version.
      */
     private boolean checkDistroRulesNewerThanSystem(
             File systemTzDataFile, DistroVersion distroVersion) throws IOException {

         // We only check the /system tzdata file and assume that other data like ICU is in sync.
         // There is a CTS test that checks ICU and bionic/libcore are in sync.
         Slog.i(logTag, "Reading /system rules version");
         String systemRulesVersion = readSystemRulesVersion(systemTzDataFile);

         String distroRulesVersion = distroVersion.rulesVersion;
         // canApply = distroRulesVersion >= systemRulesVersion
         boolean canApply = distroRulesVersion.compareTo(systemRulesVersion) >= 0;
         if (!canApply) {
             Slog.i(logTag, "Failed rules version check: distroRulesVersion="
                     + distroRulesVersion + ", systemRulesVersion=" + systemRulesVersion);
         } else {
             Slog.i(logTag, "Passed rules version check: distroRulesVersion="
                     + distroRulesVersion + ", systemRulesVersion=" + systemRulesVersion);
         }
         return canApply;
     }

     private String readSystemRulesVersion(File systemTzDataFile) throws IOException {
         if (!systemTzDataFile.exists()) {
             Slog.i(logTag, "tzdata file cannot be found in /system");
             throw new FileNotFoundException("system tzdata does not exist: " + systemTzDataFile);
         }
         return ZoneInfoDB.TzData.getRulesVersion(systemTzDataFile);
     }
 }
	/*
	* 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.
	*/
	package com.android.timezone.distro.installer;

	import com.android.timezone.distro.DistroException;
	import com.android.timezone.distro.DistroVersion;
	import com.android.timezone.distro.FileUtils;
	import com.android.timezone.distro.StagedDistroOperation;
	import com.android.timezone.distro.TimeZoneDistro;

	import android.annotation.IntDef;
	import android.util.Slog;

	import java.io.File;
	import java.io.FileNotFoundException;
	import java.io.IOException;
	import java.lang.annotation.Retention;
	import java.lang.annotation.RetentionPolicy;
	import libcore.util.TimeZoneFinder;
	import libcore.util.ZoneInfoDB;

	/**
	* A distro-validation / extraction class. Separate from the services code that uses it for easier
	* testing. This class is not thread-safe: callers are expected to handle mutual exclusion.
	*/
	public class TimeZoneDistroInstaller {

	@Retention(RetentionPolicy.SOURCE)
	@IntDef(prefix = { "INSTALL_" }, value = {
	INSTALL_SUCCESS,
	INSTALL_FAIL_BAD_DISTRO_STRUCTURE,
	INSTALL_FAIL_BAD_DISTRO_FORMAT_VERSION,
	INSTALL_FAIL_RULES_TOO_OLD,
	INSTALL_FAIL_VALIDATION_ERROR,
	})
	private @interface InstallResultType {}

	/** {@link #stageInstallWithErrorCode(TimeZoneDistro)} result code: Success. */
	public final static int INSTALL_SUCCESS = 0;

	/** {@link #stageInstallWithErrorCode(TimeZoneDistro)} result code: Distro corrupt. */
	public final static int INSTALL_FAIL_BAD_DISTRO_STRUCTURE = 1;

	/**
	* {@link #stageInstallWithErrorCode(TimeZoneDistro)} result code: Distro version incompatible.
	*/
	public final static int INSTALL_FAIL_BAD_DISTRO_FORMAT_VERSION = 2;

	/**
	* {@link #stageInstallWithErrorCode(TimeZoneDistro)} result code: Distro rules too old for
	* device.
	*/
	public final static int INSTALL_FAIL_RULES_TOO_OLD = 3;

	/**
	* {@link #stageInstallWithErrorCode(TimeZoneDistro)} result code: Distro content failed
	* validation.
	*/
	public final static int INSTALL_FAIL_VALIDATION_ERROR = 4;

	@Retention(RetentionPolicy.SOURCE)
	@IntDef(prefix = { "UNINSTALL_" }, value = {
	UNINSTALL_SUCCESS,
	UNINSTALL_NOTHING_INSTALLED,
	UNINSTALL_FAIL,
	})
	private @interface UninstallResultType {}

	/**
	* {@link #stageUninstall()} result code: An uninstall has been successfully staged.
	*/
	public final static int UNINSTALL_SUCCESS = 0;

	/**
	* {@link #stageUninstall()} result code: Nothing was installed that required an uninstall to be
	* staged.
	*/
	public final static int UNINSTALL_NOTHING_INSTALLED = 1;

	/**
	* {@link #stageUninstall()} result code: The uninstall could not be staged.
	*/
	public final static int UNINSTALL_FAIL = 2;

	// This constant must match one in system/timezone/tzdatacheck/tzdatacheck.cpp.
	private static final String STAGED_TZ_DATA_DIR_NAME = "staged";
	// This constant must match one in system/timezone/tzdatacheck/tzdatacheck.cpp.
	private static final String CURRENT_TZ_DATA_DIR_NAME = "current";
	private static final String WORKING_DIR_NAME = "working";
	private static final String OLD_TZ_DATA_DIR_NAME = "old";

	/**
	* The name of the file in the staged directory used to indicate a staged uninstallation.
	*/
	// This constant must match one in system/timezone/tzdatacheck/tzdatacheck.cpp.
	// VisibleForTesting.
	public static final String UNINSTALL_TOMBSTONE_FILE_NAME = "STAGED_UNINSTALL_TOMBSTONE";

	private final String logTag;
	private final File systemTzDataFile;
	private final File oldStagedDataDir;
	private final File stagedTzDataDir;
	private final File currentTzDataDir;
	private final File workingDir;

	public TimeZoneDistroInstaller(String logTag, File systemTzDataFile, File installDir) {
	this.logTag = logTag;
	this.systemTzDataFile = systemTzDataFile;
	oldStagedDataDir = new File(installDir, OLD_TZ_DATA_DIR_NAME);
	stagedTzDataDir = new File(installDir, STAGED_TZ_DATA_DIR_NAME);
	currentTzDataDir = new File(installDir, CURRENT_TZ_DATA_DIR_NAME);
	workingDir = new File(installDir, WORKING_DIR_NAME);
	}

	// VisibleForTesting
	File getOldStagedDataDir() {
	return oldStagedDataDir;
	}

	// VisibleForTesting
	File getStagedTzDataDir() {
	return stagedTzDataDir;
	}

	// VisibleForTesting
	File getCurrentTzDataDir() {
	return currentTzDataDir;
	}

	// VisibleForTesting
	File getWorkingDir() {
	return workingDir;
	}

	/**
	* Stage an install of the supplied content, to be installed the next time the device boots.
	*
	* <p>Errors during unpacking or staging will throw an {@link IOException}.
	* Returns {@link #INSTALL_SUCCESS} on success, or one of the failure codes.
	*/
	public @InstallResultType int stageInstallWithErrorCode(TimeZoneDistro distro)
	throws IOException {
	if (oldStagedDataDir.exists()) {
	FileUtils.deleteRecursive(oldStagedDataDir);
	}
	if (workingDir.exists()) {
	FileUtils.deleteRecursive(workingDir);
	}

	Slog.i(logTag, "Unpacking / verifying time zone update");
	try {
	unpackDistro(distro, workingDir);

	DistroVersion distroVersion;
	try {
	distroVersion = readDistroVersion(workingDir);
	} catch (DistroException e) {
	Slog.i(logTag, "Invalid distro version: " + e.getMessage());
	return INSTALL_FAIL_BAD_DISTRO_STRUCTURE;
	}
	if (distroVersion == null) {
	Slog.i(logTag, "Update not applied: Distro version could not be loaded");
	return INSTALL_FAIL_BAD_DISTRO_STRUCTURE;
	}
	if (!DistroVersion.isCompatibleWithThisDevice(distroVersion)) {
	Slog.i(logTag, "Update not applied: Distro format version check failed: "
	+ distroVersion);
	return INSTALL_FAIL_BAD_DISTRO_FORMAT_VERSION;
	}

	if (!checkDistroDataFilesExist(workingDir)) {
	Slog.i(logTag, "Update not applied: Distro is missing required data file(s)");
	return INSTALL_FAIL_BAD_DISTRO_STRUCTURE;
	}

	if (!checkDistroRulesNewerThanSystem(systemTzDataFile, distroVersion)) {
	Slog.i(logTag, "Update not applied: Distro rules version check failed");
	return INSTALL_FAIL_RULES_TOO_OLD;
	}

	// Validate the tzdata file.
	File zoneInfoFile = new File(workingDir, TimeZoneDistro.TZDATA_FILE_NAME);
	ZoneInfoDB.TzData tzData = ZoneInfoDB.TzData.loadTzData(zoneInfoFile.getPath());
	if (tzData == null) {
	Slog.i(logTag, "Update not applied: " + zoneInfoFile + " could not be loaded");
	return INSTALL_FAIL_VALIDATION_ERROR;
	}
	try {
	tzData.validate();
	} catch (IOException e) {
	Slog.i(logTag, "Update not applied: " + zoneInfoFile + " failed validation", e);
	return INSTALL_FAIL_VALIDATION_ERROR;
	} finally {
	tzData.close();
	}

	// Validate the tzlookup.xml file.
	File tzLookupFile = new File(workingDir, TimeZoneDistro.TZLOOKUP_FILE_NAME);
	if (!tzLookupFile.exists()) {
	Slog.i(logTag, "Update not applied: " + tzLookupFile + " does not exist");
	return INSTALL_FAIL_BAD_DISTRO_STRUCTURE;
	}
	try {
	TimeZoneFinder timeZoneFinder =
	TimeZoneFinder.createInstance(tzLookupFile.getPath());
	timeZoneFinder.validate();
	} catch (IOException e) {
	Slog.i(logTag, "Update not applied: " + tzLookupFile + " failed validation", e);
	return INSTALL_FAIL_VALIDATION_ERROR;
	}

	// TODO(nfuller): Add validity checks for ICU data / canarying before applying.
	// http://b/64016752

	Slog.i(logTag, "Applying time zone update");
	FileUtils.makeDirectoryWorldAccessible(workingDir);

	// Check if there is already a staged install or uninstall and remove it if there is.
	if (!stagedTzDataDir.exists()) {
	Slog.i(logTag, "Nothing to unstage at " + stagedTzDataDir);
	} else {
	Slog.i(logTag, "Moving " + stagedTzDataDir + " to " + oldStagedDataDir);
	// Move stagedTzDataDir out of the way in one operation so we can't partially delete
	// the contents.
	FileUtils.rename(stagedTzDataDir, oldStagedDataDir);
	}

	// Move the workingDir to be the new staged directory.
	Slog.i(logTag, "Moving " + workingDir + " to " + stagedTzDataDir);
	FileUtils.rename(workingDir, stagedTzDataDir);
	Slog.i(logTag, "Install staged: " + stagedTzDataDir + " successfully created");
	return INSTALL_SUCCESS;
	} finally {
	deleteBestEffort(oldStagedDataDir);
	deleteBestEffort(workingDir);
	}
	}

	/**
	* Stage an uninstall of the current timezone update in /data which, on reboot, will return the
	* device to using data from /system. If there was something else already staged it will be
	* removed by this call.
	*
	* Returns {@link #UNINSTALL_SUCCESS} if staging the uninstallation was
	* successful and reboot will be required. Returns {@link #UNINSTALL_NOTHING_INSTALLED} if
	* there was nothing installed in /data that required an uninstall to be staged, anything that
	* was staged will have been removed and therefore no reboot is required.
	*
	* <p>Errors encountered during uninstallation will throw an {@link IOException}.
	*/
	public @UninstallResultType int stageUninstall() throws IOException {
	Slog.i(logTag, "Uninstalling time zone update");

	if (oldStagedDataDir.exists()) {
	// If we can't remove this, an exception is thrown and we don't continue.
	FileUtils.deleteRecursive(oldStagedDataDir);
	}
	if (workingDir.exists()) {
	FileUtils.deleteRecursive(workingDir);
	}

	try {
	// Check if there is already an install or uninstall staged and remove it.
	if (!stagedTzDataDir.exists()) {
	Slog.i(logTag, "Nothing to unstage at " + stagedTzDataDir);
	} else {
	Slog.i(logTag, "Moving " + stagedTzDataDir + " to " + oldStagedDataDir);
	// Move stagedTzDataDir out of the way in one operation so we can't partially delete
	// the contents.
	FileUtils.rename(stagedTzDataDir, oldStagedDataDir);
	}

	// If there's nothing actually installed, there's nothing to uninstall so no need to
	// stage anything.
	if (!currentTzDataDir.exists()) {
	Slog.i(logTag, "Nothing to uninstall at " + currentTzDataDir);
	return UNINSTALL_NOTHING_INSTALLED;
	}

	// Stage an uninstall in workingDir.
	FileUtils.ensureDirectoriesExist(workingDir, true /* makeWorldReadable */);
	FileUtils.createEmptyFile(new File(workingDir, UNINSTALL_TOMBSTONE_FILE_NAME));

	// Move the workingDir to be the new staged directory.
	Slog.i(logTag, "Moving " + workingDir + " to " + stagedTzDataDir);
	FileUtils.rename(workingDir, stagedTzDataDir);
	Slog.i(logTag, "Uninstall staged: " + stagedTzDataDir + " successfully created");

	return UNINSTALL_SUCCESS;
	} finally {
	deleteBestEffort(oldStagedDataDir);
	deleteBestEffort(workingDir);
	}
	}

	/**
	* Reads the currently installed distro version. Returns {@code null} if there is no distro
	* installed.
	*
	* @throws IOException if there was a problem reading data from /data
	* @throws DistroException if there was a problem with the installed distro format/structure
	*/
	public DistroVersion getInstalledDistroVersion() throws DistroException, IOException {
	if (!currentTzDataDir.exists()) {
	return null;
	}
	return readDistroVersion(currentTzDataDir);
	}

	/**
	* Reads information about any currently staged distro operation. Returns {@code null} if there
	* is no distro operation staged.
	*
	* @throws IOException if there was a problem reading data from /data
	* @throws DistroException if there was a problem with the staged distro format/structure
	*/
	public StagedDistroOperation getStagedDistroOperation() throws DistroException, IOException {
	if (!stagedTzDataDir.exists()) {
	return null;
	}
	if (new File(stagedTzDataDir, UNINSTALL_TOMBSTONE_FILE_NAME).exists()) {
	return StagedDistroOperation.uninstall();
	} else {
	return StagedDistroOperation.install(readDistroVersion(stagedTzDataDir));
	}
	}

	/**
	* Reads the timezone rules version present in /system. i.e. the version that would be present
	* after a factory reset.
	*
	* @throws IOException if there was a problem reading data
	*/
	public String getSystemRulesVersion() throws IOException {
	return readSystemRulesVersion(systemTzDataFile);
	}

	private void deleteBestEffort(File dir) {
	if (dir.exists()) {
	Slog.i(logTag, "Deleting " + dir);
	try {
	FileUtils.deleteRecursive(dir);
	} catch (IOException e) {
	// Logged but otherwise ignored.
	Slog.w(logTag, "Unable to delete " + dir, e);
	}
	}
	}

	private void unpackDistro(TimeZoneDistro distro, File targetDir) throws IOException {
	Slog.i(logTag, "Unpacking update content to: " + targetDir);
	distro.extractTo(targetDir);
	}

	private boolean checkDistroDataFilesExist(File unpackedContentDir) throws IOException {
	Slog.i(logTag, "Verifying distro contents");
	return FileUtils.filesExist(unpackedContentDir,
	TimeZoneDistro.TZDATA_FILE_NAME,
	TimeZoneDistro.ICU_DATA_FILE_NAME);
	}

	private DistroVersion readDistroVersion(File distroDir) throws DistroException, IOException {
	Slog.d(logTag, "Reading distro format version: " + distroDir);
	File distroVersionFile = new File(distroDir, TimeZoneDistro.DISTRO_VERSION_FILE_NAME);
	if (!distroVersionFile.exists()) {
	throw new DistroException("No distro version file found: " + distroVersionFile);
	}
	byte[] versionBytes =
	FileUtils.readBytes(distroVersionFile, DistroVersion.DISTRO_VERSION_FILE_LENGTH);
	return DistroVersion.fromBytes(versionBytes);
	}

	/**
	* Returns true if the the distro IANA rules version is >= system IANA rules version.
	*/
	private boolean checkDistroRulesNewerThanSystem(
	File systemTzDataFile, DistroVersion distroVersion) throws IOException {

	// We only check the /system tzdata file and assume that other data like ICU is in sync.
	// There is a CTS test that checks ICU and bionic/libcore are in sync.
	Slog.i(logTag, "Reading /system rules version");
	String systemRulesVersion = readSystemRulesVersion(systemTzDataFile);

	String distroRulesVersion = distroVersion.rulesVersion;
	// canApply = distroRulesVersion >= systemRulesVersion
	boolean canApply = distroRulesVersion.compareTo(systemRulesVersion) >= 0;
	if (!canApply) {
	Slog.i(logTag, "Failed rules version check: distroRulesVersion="
	+ distroRulesVersion + ", systemRulesVersion=" + systemRulesVersion);
	} else {
	Slog.i(logTag, "Passed rules version check: distroRulesVersion="
	+ distroRulesVersion + ", systemRulesVersion=" + systemRulesVersion);
	}
	return canApply;
	}

	private String readSystemRulesVersion(File systemTzDataFile) throws IOException {
	if (!systemTzDataFile.exists()) {
	Slog.i(logTag, "tzdata file cannot be found in /system");
	throw new FileNotFoundException("system tzdata does not exist: " + systemTzDataFile);
	}
	return ZoneInfoDB.TzData.getRulesVersion(systemTzDataFile);
	}
	}