Reconcile private volumes when mounted.

Many things can happen while a private volume is ejected, so we need
to reconcile newly mounted volumes against known state.

First, user IDs can be recycled, so we store the serial number in the
extended attributes of the /data/user/[id] directory inode.  Since a
serial number is always unique, we can quickly determine if a user
directory "10" really belongs to the current user "10".  When we
detect a mismatched serial number, we destroy all data belonging to
that user.  Gracefully handles upgrade case and assumes current serial
number is valid when none is defined.

Second, we destroy apps that we find no record of, either due to
uninstallation while the volume was unmounted, or reinstallation on
another volume.

When mounting a volume, ensure that data directories exist for all
current users.  Similarly, create data directories on all mounted
volumes when creating a user.  When forgetting a volume, gracefully
uninstall any apps that had been installed on that volume.

Bug: 20674082, 20275572
Change-Id: I4e3448837f7c03daf00d71681ebdc96e3d8b9cc9

2 files changed, 3 insertions, 18 deletions

diff --git a/core/java/android/content/pm/PackageManager.java b/core/java/android/content/pm/PackageManager.java
index dd1c5c2..1a4378b 100644
--- a/core/java/android/content/pm/PackageManager.java
+++ b/core/java/android/content/pm/PackageManager.java
@@ -4441,22 +4441,6 @@ public abstract class PackageManager {
     public abstract @NonNull PackageInstaller getPackageInstaller();
 
     /**
-     * Returns the data directory for a particular package and user.
-     *
-     * @hide
-     */
-    public static File getDataDirForUser(String volumeUuid, String packageName, int userId) {
-        // TODO: This should be shared with Installer's knowledge of user directory
-        final File base;
-        if (TextUtils.isEmpty(volumeUuid)) {
-            base = Environment.getDataDirectory();
-        } else {
-            base = new File("/mnt/expand/" + volumeUuid);
-        }
-        return new File(base, "user/" + userId + "/" + packageName);
-    }
-
-    /**
      * Adds a {@link CrossProfileIntentFilter}. After calling this method all intents sent from the
      * user with id sourceUserId can also be be resolved by activities in the user with id
      * targetUserId if they match the specified intent filter.
diff --git a/core/java/android/content/pm/PackageParser.java b/core/java/android/content/pm/PackageParser.java
index 64376c1..48ffb98 100644
--- a/core/java/android/content/pm/PackageParser.java
+++ b/core/java/android/content/pm/PackageParser.java
@@ -36,6 +36,7 @@ import android.content.res.TypedArray;
 import android.content.res.XmlResourceParser;
 import android.os.Build;
 import android.os.Bundle;
+import android.os.Environment;
 import android.os.FileUtils;
 import android.os.PatternMatcher;
 import android.os.UserHandle;
@@ -4785,7 +4786,7 @@ public class PackageParser {
         // Make shallow copy so we can store the metadata/libraries safely
         ApplicationInfo ai = new ApplicationInfo(p.applicationInfo);
         ai.uid = UserHandle.getUid(userId, ai.uid);
-        ai.dataDir = PackageManager.getDataDirForUser(ai.volumeUuid, ai.packageName, userId)
+        ai.dataDir = Environment.getDataUserPackageDirectory(ai.volumeUuid, userId, ai.packageName)
                 .getAbsolutePath();
         if ((flags & PackageManager.GET_META_DATA) != 0) {
             ai.metaData = p.mAppMetaData;
@@ -4812,7 +4813,7 @@ public class PackageParser {
         // make a copy.
         ai = new ApplicationInfo(ai);
         ai.uid = UserHandle.getUid(userId, ai.uid);
-        ai.dataDir = PackageManager.getDataDirForUser(ai.volumeUuid, ai.packageName, userId)
+        ai.dataDir = Environment.getDataUserPackageDirectory(ai.volumeUuid, userId, ai.packageName)
                 .getAbsolutePath();
         if (state.stopped) {
             ai.flags |= ApplicationInfo.FLAG_STOPPED;