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Commit 5228cc20 authored by Varun Shah's avatar Varun Shah
Browse files

Prune obsolete UsageStats data on upgrade. 

When a database upgrade is performed for UsageStats, prune all
UsageStats data that belongs to packages that have been uninstalled.
This ensures that all data in UsageStats in R belongs to packages that
are currently installed or to those packages whose DONT_DELETE_DATA flag
was set when uninstalling.

Also remove the clean-up mapping step on boot. That was added as a
safety measure to ensure the mappings file is always updated. However,
with the addition of the prune job on package uninstalls and this CL,
that step is now unnecessary.

Bug: 143889121
Test: atest UsageStatsDatabase
Change-Id: Ib3d24dead4cd0e23145c15e7b1f88e2e20aadcaa
parent ece1fa0b

services/usage/java/com/android/server/usage/UsageStatsDatabase.java

+75 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ import java.io.OutputStream; 
import java.nio.file.Files;

import java.nio.file.StandardCopyOption;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;



/**
@@ -122,6 +123,7 @@ public class UsageStatsDatabase { 
    private int mCurrentVersion;

    private boolean mFirstUpdate;

    private boolean mNewUpdate;

    private boolean mUpgradePerformed;



    // The obfuscated packages to tokens mappings file

    private final File mPackageMappingsFile;
@@ -325,6 +327,13 @@ public class UsageStatsDatabase { 
        return mNewUpdate;

    }



    /**

     * Was an upgrade performed when this database was initialized?

     */

    boolean wasUpgradePerformed() {

        return mUpgradePerformed;

    }



    private void checkVersionAndBuildLocked() {

        int version;

        String buildFingerprint;
@@ -397,6 +406,8 @@ public class UsageStatsDatabase { 
        if (mUpdateBreadcrumb.exists()) {

            // Files should be up to date with current version. Clear the version update breadcrumb

            mUpdateBreadcrumb.delete();

            // update mUpgradePerformed after breadcrumb is deleted to indicate a successful upgrade

            mUpgradePerformed = true;

        }



        if (mBackupsDir.exists() && !KEEP_BACKUP_DIR) {
@@ -594,6 +605,70 @@ public class UsageStatsDatabase { 
        }

    }



    /**

     * Iterates through all the files on disk and prunes any data that belongs to packages that have

     * been uninstalled (packages that are not in the given list).

     * Note: this should only be called once, when there has been a database upgrade.

     *

     * @param installedPackages map of installed packages (package_name:package_install_time)

     */

    void prunePackagesDataOnUpgrade(HashMap<String, Long> installedPackages) {

        if (installedPackages == null || installedPackages.isEmpty()) {

            return;

        }

        synchronized (mLock) {

            for (int i = 0; i < mIntervalDirs.length; i++) {

                final File[] files = mIntervalDirs[i].listFiles();

                if (files == null) {

                    continue;

                }

                for (int j = 0; j < files.length; j++) {

                    try {

                        final IntervalStats stats = new IntervalStats();

                        final AtomicFile atomicFile = new AtomicFile(files[j]);

                        readLocked(atomicFile, stats, mCurrentVersion, mPackagesTokenData);

                        if (!pruneStats(installedPackages, stats)) {

                            continue; // no stats were pruned so no need to rewrite

                        }

                        writeLocked(atomicFile, stats, mCurrentVersion, mPackagesTokenData);

                    } catch (Exception e) {

                        Slog.e(TAG, "Failed to prune data from: " + files[j].toString());

                    }

                }

            }

        }

    }



    private boolean pruneStats(HashMap<String, Long> installedPackages, IntervalStats stats) {

        boolean dataPruned = false;



        // prune old package usage stats

        for (int i = stats.packageStats.size() - 1; i >= 0; i--) {

            final UsageStats usageStats = stats.packageStats.valueAt(i);

            final Long timeInstalled = installedPackages.get(usageStats.mPackageName);

            if (timeInstalled == null || timeInstalled > usageStats.mEndTimeStamp) {

                stats.packageStats.removeAt(i);

                dataPruned = true;

            }

        }

        if (dataPruned) {

            // ensure old stats don't linger around during the obfuscation step on write

            stats.packageStatsObfuscated.clear();

        }



        // prune old events

        for (int i = stats.events.size() - 1; i >= 0; i--) {

            final UsageEvents.Event event = stats.events.get(i);

            final Long timeInstalled = installedPackages.get(event.mPackage);

            if (timeInstalled == null || timeInstalled > event.mTimeStamp) {

                stats.events.remove(i);

                dataPruned = true;

            }

        }



        return dataPruned;

    }



    public void onTimeChanged(long timeDiffMillis) {

        synchronized (mLock) {

            StringBuilder logBuilder = new StringBuilder();

services/usage/java/com/android/server/usage/UserUsageStatsService.java

+20 −38
Original line number Diff line number Diff line
@@ -34,10 +34,9 @@ import android.app.usage.UsageEvents.Event; 
import android.app.usage.UsageStats;

import android.app.usage.UsageStatsManager;

import android.content.Context;

import android.content.pm.ApplicationInfo;

import android.content.pm.PackageManagerInternal;

import android.content.pm.PackageInfo;

import android.content.pm.PackageManager;

import android.content.res.Configuration;

import android.os.Process;

import android.os.SystemClock;

import android.text.format.DateUtils;

import android.util.ArrayMap;
@@ -47,7 +46,6 @@ import android.util.Slog; 
import android.util.SparseIntArray;



import com.android.internal.util.IndentingPrintWriter;

import com.android.server.LocalServices;

import com.android.server.usage.UsageStatsDatabase.StatCombiner;



import java.io.File;
@@ -55,7 +53,7 @@ import java.io.IOException; 
import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.HashSet;

import java.util.HashMap;

import java.util.List;



/**
@@ -115,6 +113,9 @@ class UserUsageStatsService { 
    void init(final long currentTimeMillis) {

        readPackageMappingsLocked();

        mDatabase.init(currentTimeMillis);

        if (mDatabase.wasUpgradePerformed()) {

            mDatabase.prunePackagesDataOnUpgrade(getInstalledPackages());

        }



        int nullCount = 0;

        for (int i = 0; i < mCurrentStats.length; i++) {
@@ -184,7 +185,6 @@ class UserUsageStatsService { 
    private void readPackageMappingsLocked() {

        mDatabase.readMappingsLocked();

        updatePackageMappingsLocked();

        cleanUpPackageMappingsLocked();

    }



    /**
@@ -216,42 +216,24 @@ class UserUsageStatsService { 
    }



    /**

     * Queries Package Manager for a list of installed packages and removes those packages from

     * mPackagesTokenData which are not installed any more.

     * This will only happen once per device boot, when the user is unlocked for the first time.

     */

    private void cleanUpPackageMappingsLocked() {

        final long timeNow = System.currentTimeMillis();

        /*

         Note (b/142501248): PackageManagerInternal#getInstalledApplications is not lightweight.

         Once its implementation is updated, or it's replaced with a better alternative, update

         the call here to use it. For now, using the heavy #getInstalledApplications is okay since

         this clean-up is only performed once every boot.

     * Fetches a map of package names to their install times. This includes all installed packages,

     * including those packages which have been uninstalled with the DONT_DELETE_DATA flag.

     * Note: this is supposed be a helper method which is only used on database upgrades - it should

     * not be called otherwise since it's implementation performs a heavy query to package manager.

     */

        final PackageManagerInternal packageManagerInternal =

                LocalServices.getService(PackageManagerInternal.class);

        if (packageManagerInternal == null) {

            return;

    private HashMap<String, Long> getInstalledPackages() {

        final PackageManager packageManager = mContext.getPackageManager();

        if (packageManager == null) {

            return null;

        }

        final List<ApplicationInfo> installedPackages =

                packageManagerInternal.getInstalledApplications(0, mUserId, Process.SYSTEM_UID);

        // convert the package list to a set for easy look-ups

        final HashSet<String> packagesSet = new HashSet<>(installedPackages.size());

        final List<PackageInfo> installedPackages = packageManager.getInstalledPackagesAsUser(

                PackageManager.MATCH_UNINSTALLED_PACKAGES, mUserId);

        final HashMap<String, Long> packagesMap = new HashMap<>();

        for (int i = installedPackages.size() - 1; i >= 0; i--) {

            packagesSet.add(installedPackages.get(i).packageName);

        }

        final List<String> removedPackages = new ArrayList<>();

        // populate list of packages that are found in the mappings but not in the installed list

        for (int i = mDatabase.mPackagesTokenData.packagesToTokensMap.size() - 1; i >= 0; i--) {

            if (!packagesSet.contains(mDatabase.mPackagesTokenData.packagesToTokensMap.keyAt(i))) {

                removedPackages.add(mDatabase.mPackagesTokenData.packagesToTokensMap.keyAt(i));

            }

        }



        // remove packages in the mappings that are no longer installed

        for (int i = removedPackages.size() - 1; i >= 0; i--) {

            mDatabase.mPackagesTokenData.removePackage(removedPackages.get(i), timeNow);

            final PackageInfo packageInfo = installedPackages.get(i);

            packagesMap.put(packageInfo.packageName, packageInfo.firstInstallTime);

        }

        return packagesMap;

    }



    boolean pruneUninstalledPackagesData() {