DB Wipe detection

- Create a check file for each database in order to detect
1) an unexpected DB file removal
2) DB wipe caused by a DB corruption.

- Either case, do a WTF to collect information on APR.

- Also print file timestamps in "dumpsys dbinfo". Example:

=====================
Database files in /data/system:
  locksettings.db                            20480b ctime=2018-10-23T22:48:35Z mtime=2018-10-23T22:48:35Z atime=2018-10-23T18:54:12Z
  locksettings.db-wipecheck                      0b ctime=2018-10-23T18:54:12Z mtime=2018-10-23T18:54:12Z atime=2018-10-23T18:54:12Z
  notification_log.db                        45056b ctime=2018-10-23T22:48:08Z mtime=2018-10-23T22:48:08Z atime=2018-10-23T18:54:13Z
    :
=====================

Change-Id: I77fbeb0bb635c787aba797412f116475fecbe41c
Fixes: 117886381
Test: manual test

Test 1: corruption
1. Stop CP2 process (adb shell killall android.process.acore)
2. shell 'echo abc > /data/user/0/com.android.providers.contacts/databases/contacts2.db'
3. Launch the contacts app.

Test 2: Unexpected file removal
1. Stop CP2 process (adb shell killall android.process.acore)
2. shell 'rm -f /data/user/0/com.android.providers.contacts/databases/contacts2.db'
3. Launch the contacts app.

In both cases, logcat shows a client side stacktrace and also a WTF. (am_wtf)

5 files changed, 145 insertions, 7 deletions

diff --git a/core/java/android/database/sqlite/SQLiteConnection.java b/core/java/android/database/sqlite/SQLiteConnection.java
index 5c4f16a7cf3d..20505ca803dc 100644
--- a/core/java/android/database/sqlite/SQLiteConnection.java
+++ b/core/java/android/database/sqlite/SQLiteConnection.java
@@ -34,6 +34,7 @@ import dalvik.system.BlockGuard;
 import dalvik.system.CloseGuard;
 
 import java.io.File;
+import java.io.IOException;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Date;
@@ -414,6 +415,10 @@ public final class SQLiteConnection implements CancellationSignal.OnCancelListen
         final String newLocale = mConfiguration.locale.toString();
         nativeRegisterLocalizedCollators(mConnectionPtr, newLocale);
 
+        if (!mConfiguration.isInMemoryDb()) {
+            checkDatabaseWiped();
+        }
+
         // If the database is read-only, we cannot modify the android metadata table
         // or existing indexes.
         if (mIsReadOnlyConnection) {
@@ -449,6 +454,36 @@ public final class SQLiteConnection implements CancellationSignal.OnCancelListen
         }
     }
 
+    private void checkDatabaseWiped() {
+        if (!SQLiteGlobal.checkDbWipe()) {
+            return;
+        }
+        try {
+            final File checkFile = new File(mConfiguration.path
+                    + SQLiteGlobal.WIPE_CHECK_FILE_SUFFIX);
+
+            final boolean hasMetadataTable = executeForLong(
+                    "SELECT count(*) FROM sqlite_master"
+                            + " WHERE type='table' AND name='android_metadata'", null, null) > 0;
+            final boolean hasCheckFile = checkFile.exists();
+
+            if (!mIsReadOnlyConnection && !hasCheckFile) {
+                // Create the check file, unless it's a readonly connection,
+                // in which case we can't create the metadata table anyway.
+                checkFile.createNewFile();
+            }
+
+            if (!hasMetadataTable && hasCheckFile) {
+                // Bad. The DB is gone unexpectedly.
+                SQLiteDatabase.wipeDetected(mConfiguration.path, "unknown");
+            }
+
+        } catch (RuntimeException | IOException ex) {
+            SQLiteDatabase.wtfAsSystemServer(TAG,
+                    "Unexpected exception while checking for wipe", ex);
+        }
+    }
+
     // Called by SQLiteConnectionPool only.
     void reconfigure(SQLiteDatabaseConfiguration configuration) {
         mOnlyAllowReadOnlyOperations = false;
diff --git a/core/java/android/database/sqlite/SQLiteConnectionPool.java b/core/java/android/database/sqlite/SQLiteConnectionPool.java
index 3ee348ba4865..dbc176614daf 100644
--- a/core/java/android/database/sqlite/SQLiteConnectionPool.java
+++ b/core/java/android/database/sqlite/SQLiteConnectionPool.java
@@ -24,6 +24,7 @@ import android.os.Message;
 import android.os.OperationCanceledException;
 import android.os.SystemClock;
 import android.text.TextUtils;
+import android.util.ArraySet;
 import android.util.Log;
 import android.util.PrefixPrinter;
 import android.util.Printer;
@@ -34,6 +35,7 @@ import com.android.internal.annotations.VisibleForTesting;
 import dalvik.system.CloseGuard;
 
 import java.io.Closeable;
+import java.io.File;
 import java.util.ArrayList;
 import java.util.Map;
 import java.util.WeakHashMap;
@@ -1105,9 +1107,12 @@ public final class SQLiteConnectionPool implements Closeable {
      * @param printer The printer to receive the dump, not null.
      * @param verbose True to dump more verbose information.
      */
-    public void dump(Printer printer, boolean verbose) {
+    public void dump(Printer printer, boolean verbose, ArraySet<String> directories) {
         Printer indentedPrinter = PrefixPrinter.create(printer, "    ");
         synchronized (mLock) {
+            if (directories != null) {
+                directories.add(new File(mConfiguration.path).getParent());
+            }
             printer.println("Connection pool for " + mConfiguration.path + ":");
             printer.println("  Open: " + mIsOpen);
             printer.println("  Max connections: " + mMaxConnectionPoolSize);
diff --git a/core/java/android/database/sqlite/SQLiteDatabase.java b/core/java/android/database/sqlite/SQLiteDatabase.java
index eb5c720d6309..f9c2c3e2c983 100644
--- a/core/java/android/database/sqlite/SQLiteDatabase.java
+++ b/core/java/android/database/sqlite/SQLiteDatabase.java
@@ -22,6 +22,8 @@ import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.UnsupportedAppUsage;
 import android.app.ActivityManager;
+import android.app.ActivityThread;
+import android.content.ContentResolver;
 import android.content.ContentValues;
 import android.database.Cursor;
 import android.database.DatabaseErrorHandler;
@@ -34,6 +36,7 @@ import android.os.Looper;
 import android.os.OperationCanceledException;
 import android.os.SystemProperties;
 import android.text.TextUtils;
+import android.util.ArraySet;
 import android.util.EventLog;
 import android.util.Log;
 import android.util.Pair;
@@ -45,9 +48,14 @@ import dalvik.system.CloseGuard;
 
 import java.io.File;
 import java.io.FileFilter;
+import java.io.IOException;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.attribute.BasicFileAttributes;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
@@ -808,6 +816,12 @@ public final class SQLiteDatabase extends SQLiteClosable {
      * @return True if the database was successfully deleted.
      */
     public static boolean deleteDatabase(@NonNull File file) {
+        return deleteDatabase(file, /*removeCheckFile=*/ true);
+    }
+
+
+    /** @hide */
+    public static boolean deleteDatabase(@NonNull File file, boolean removeCheckFile) {
         if (file == null) {
             throw new IllegalArgumentException("file must not be null");
         }
@@ -818,6 +832,9 @@ public final class SQLiteDatabase extends SQLiteClosable {
         deleted |= new File(file.getPath() + "-shm").delete();
         deleted |= new File(file.getPath() + "-wal").delete();
 
+        // This file is not a standard SQLite file, so don't update the deleted flag.
+        new File(file.getPath() + SQLiteGlobal.WIPE_CHECK_FILE_SUFFIX).delete();
+
         File dir = file.getParentFile();
         if (dir != null) {
             final String prefix = file.getName() + "-mj";
@@ -2170,21 +2187,61 @@ public final class SQLiteDatabase extends SQLiteClosable {
      * Dump detailed information about all open databases in the current process.
      * Used by bug report.
      */
-    static void dumpAll(Printer printer, boolean verbose) {
+    static void dumpAll(Printer printer, boolean verbose, boolean isSystem) {
+        // Use this ArraySet to collect file paths.
+        final ArraySet<String> directories = new ArraySet<>();
+
         for (SQLiteDatabase db : getActiveDatabases()) {
-            db.dump(printer, verbose);
+            db.dump(printer, verbose, isSystem, directories);
+        }
+
+        // Dump DB files in the directories.
+        if (directories.size() > 0) {
+            final String[] dirs = directories.toArray(new String[directories.size()]);
+            Arrays.sort(dirs);
+            for (String dir : dirs) {
+                dumpDatabaseDirectory(printer, new File(dir), isSystem);
+            }
         }
     }
 
-    private void dump(Printer printer, boolean verbose) {
+    private void dump(Printer printer, boolean verbose, boolean isSystem, ArraySet directories) {
         synchronized (mLock) {
             if (mConnectionPoolLocked != null) {
                 printer.println("");
-                mConnectionPoolLocked.dump(printer, verbose);
+                mConnectionPoolLocked.dump(printer, verbose, directories);
             }
         }
     }
 
+    private static void dumpDatabaseDirectory(Printer pw, File dir, boolean isSystem) {
+        pw.println("");
+        pw.println("Database files in " + dir.getAbsolutePath() + ":");
+        final File[] files = dir.listFiles();
+        if (files == null || files.length == 0) {
+            pw.println("  [none]");
+            return;
+        }
+        Arrays.sort(files, (a, b) -> a.getName().compareTo(b.getName()));
+
+        for (File f : files) {
+            if (isSystem) {
+                // If called within the system server, the directory contains other files too, so
+                // filter by file extensions.
+                // (If it's an app, just print all files because they may not use *.db
+                // extension.)
+                final String name = f.getName();
+                if (!(name.endsWith(".db") || name.endsWith(".db-wal")
+                        || name.endsWith(".db-journal")
+                        || name.endsWith(SQLiteGlobal.WIPE_CHECK_FILE_SUFFIX))) {
+                    continue;
+                }
+            }
+            pw.println(String.format("  %-40s %7db %s", f.getName(), f.length(),
+                    SQLiteDatabase.getFileTimestamps(f.getAbsolutePath())));
+        }
+    }
+
     /**
      * Returns list of full pathnames of all attached databases including the main database
      * by executing 'pragma database_list' on the database.
@@ -2611,7 +2668,7 @@ public final class SQLiteDatabase extends SQLiteClosable {
                 return this;
             }
 
-            /**
+            /**w
              * Sets <a href="https://sqlite.org/pragma.html#pragma_synchronous">synchronous mode</a>
              * .
              * @return
@@ -2646,5 +2703,34 @@ public final class SQLiteDatabase extends SQLiteClosable {
     @Retention(RetentionPolicy.SOURCE)
     public @interface DatabaseOpenFlags {}
 
+    /** @hide */
+    public static void wipeDetected(String filename, String reason) {
+        wtfAsSystemServer(TAG, "DB wipe detected:"
+                + " package=" + ActivityThread.currentPackageName()
+                + " reason=" + reason
+                + " file=" + filename
+                + " " + getFileTimestamps(filename)
+                + " checkfile " + getFileTimestamps(filename + SQLiteGlobal.WIPE_CHECK_FILE_SUFFIX),
+                new Throwable("STACKTRACE"));
+    }
+
+    /** @hide */
+    public static String getFileTimestamps(String path) {
+        try {
+            BasicFileAttributes attr = Files.readAttributes(
+                    FileSystems.getDefault().getPath(path), BasicFileAttributes.class);
+            return "ctime=" + attr.creationTime()
+                    + " mtime=" + attr.lastModifiedTime()
+                    + " atime=" + attr.lastAccessTime();
+        } catch (IOException e) {
+            return "[unable to obtain timestamp]";
+        }
+    }
+
+    /** @hide */
+    static void wtfAsSystemServer(String tag, String message, Throwable stacktrace) {
+        Log.e(tag, message, stacktrace);
+        ContentResolver.onDbCorruption(tag, message, stacktrace);
+    }
 }
 
diff --git a/core/java/android/database/sqlite/SQLiteDebug.java b/core/java/android/database/sqlite/SQLiteDebug.java
index 1c6620467b7c..f220205b5f26 100644
--- a/core/java/android/database/sqlite/SQLiteDebug.java
+++ b/core/java/android/database/sqlite/SQLiteDebug.java
@@ -189,6 +189,11 @@ public final class SQLiteDebug {
      * @param args Command-line arguments supplied to dumpsys dbinfo
      */
     public static void dump(Printer printer, String[] args) {
+        dump(printer, args, false);
+    }
+
+    /** @hide */
+    public static void dump(Printer printer, String[] args, boolean isSystem) {
         boolean verbose = false;
         for (String arg : args) {
             if (arg.equals("-v")) {
@@ -196,6 +201,6 @@ public final class SQLiteDebug {
             }
         }
 
-        SQLiteDatabase.dumpAll(printer, verbose);
+        SQLiteDatabase.dumpAll(printer, verbose, isSystem);
     }
 }
diff --git a/core/java/android/database/sqlite/SQLiteGlobal.java b/core/java/android/database/sqlite/SQLiteGlobal.java
index 67e5f65d5a1f..ff286fdb42df 100644
--- a/core/java/android/database/sqlite/SQLiteGlobal.java
+++ b/core/java/android/database/sqlite/SQLiteGlobal.java
@@ -42,6 +42,9 @@ public final class SQLiteGlobal {
     /** @hide */
     public static final String SYNC_MODE_FULL = "FULL";
 
+    /** @hide */
+    static final String WIPE_CHECK_FILE_SUFFIX = "-wipecheck";
+
     private static final Object sLock = new Object();
 
     private static int sDefaultPageSize;
@@ -181,4 +184,8 @@ public final class SQLiteGlobal {
                         com.android.internal.R.integer.db_wal_truncate_size));
     }
 
+    /** @hide */
+    public static boolean checkDbWipe() {
+        return true;
+    }
 }