Full backup now saves getExternalFilesDir() content with the app data

... instead of only saving it with the enormous "shared storage" generic
data blob.  In parallel, we no longer store managed app-specific files
on external storage as part of the generic shared-storage blob.

At restore time we just go ahead and apply such files, though,
because they're a priori going to be part of an archive generated by
an older version of the platform, so that's how the data is expected
to be handled in those circumstances.

Bug 6718844

Change-Id: I4410514d368b11d74b3afe6b92d363d4115a3415

3 files changed, 25 insertions, 1 deletions

diff --git a/core/java/android/app/backup/BackupAgent.java b/core/java/android/app/backup/BackupAgent.java
index 9ad33a5a4105..b678df748748 100644
--- a/core/java/android/app/backup/BackupAgent.java
+++ b/core/java/android/app/backup/BackupAgent.java
@@ -227,6 +227,7 @@ public abstract class BackupAgent extends ContextWrapper {
         String libDir = (appInfo.nativeLibraryDir != null)
                 ? new File(appInfo.nativeLibraryDir).getCanonicalPath()
                 : null;
+        String externalFilesDir = getExternalFilesDir(null).getCanonicalPath();
 
         // Filters, the scan queue, and the set of resulting entities
         HashSet<String> filterSet = new HashSet<String>();
@@ -254,6 +255,12 @@ public abstract class BackupAgent extends ContextWrapper {
         filterSet.add(databaseDir);
         filterSet.remove(sharedPrefsDir);
         fullBackupFileTree(packageName, FullBackup.SHAREDPREFS_TREE_TOKEN, sharedPrefsDir, filterSet, data);
+
+        // getExternalFilesDir() location associated with this app.  Technically there should
+        // not be any files here if the app does not properly have permission to access
+        // external storage, but edge cases happen. fullBackupFileTree() catches
+        // IOExceptions and similar, and treats them as non-fatal, so we rely on that here.
+        fullBackupFileTree(packageName, FullBackup.MANAGED_EXTERNAL_TREE_TOKEN, externalFilesDir, null, data);
     }
 
     /**
@@ -274,6 +281,7 @@ public abstract class BackupAgent extends ContextWrapper {
         String spDir;
         String cacheDir;
         String libDir;
+        String efDir;
         String filePath;
 
         ApplicationInfo appInfo = getApplicationInfo();
@@ -287,6 +295,7 @@ public abstract class BackupAgent extends ContextWrapper {
             libDir = (appInfo.nativeLibraryDir == null)
                     ? null
                     : new File(appInfo.nativeLibraryDir).getCanonicalPath();
+            efDir = getExternalFilesDir(null).getCanonicalPath();
 
             // Now figure out which well-defined tree the file is placed in, working from
             // most to least specific.  We also specifically exclude the lib and cache dirs.
@@ -315,6 +324,9 @@ public abstract class BackupAgent extends ContextWrapper {
         } else if (filePath.startsWith(mainDir)) {
             domain = FullBackup.ROOT_TREE_TOKEN;
             rootpath = mainDir;
+        } else if (filePath.startsWith(efDir)) {
+            domain = FullBackup.MANAGED_EXTERNAL_TREE_TOKEN;
+            rootpath = efDir;
         } else {
             Log.w(TAG, "File " + filePath + " is in an unsupported location; skipping");
             return;
@@ -438,6 +450,8 @@ public abstract class BackupAgent extends ContextWrapper {
             basePath = getSharedPrefsFile("foo").getParentFile().getCanonicalPath();
         } else if (domain.equals(FullBackup.CACHE_TREE_TOKEN)) {
             basePath = getCacheDir().getCanonicalPath();
+        } else if (domain.equals(FullBackup.MANAGED_EXTERNAL_TREE_TOKEN)) {
+            basePath = getExternalFilesDir(null).getCanonicalPath();
         } else {
             // Not a supported location
             Log.i(TAG, "Data restored from non-app domain " + domain + ", ignoring");
diff --git a/core/java/android/app/backup/FullBackup.java b/core/java/android/app/backup/FullBackup.java
index f859599e18ce..2fe08f34b49e 100644
--- a/core/java/android/app/backup/FullBackup.java
+++ b/core/java/android/app/backup/FullBackup.java
@@ -46,6 +46,7 @@ public class FullBackup {
     public static final String DATA_TREE_TOKEN = "f";
     public static final String DATABASE_TREE_TOKEN = "db";
     public static final String SHAREDPREFS_TREE_TOKEN = "sp";
+    public static final String MANAGED_EXTERNAL_TREE_TOKEN = "ef";
     public static final String CACHE_TREE_TOKEN = "c";
     public static final String SHARED_STORAGE_TOKEN = "shared";
 
diff --git a/packages/SharedStorageBackup/src/com/android/sharedstoragebackup/SharedStorageAgent.java b/packages/SharedStorageBackup/src/com/android/sharedstoragebackup/SharedStorageAgent.java
index a6415b2fb8b4..89f84fcf953e 100644
--- a/packages/SharedStorageBackup/src/com/android/sharedstoragebackup/SharedStorageAgent.java
+++ b/packages/SharedStorageBackup/src/com/android/sharedstoragebackup/SharedStorageAgent.java
@@ -4,6 +4,7 @@ import android.app.backup.FullBackupAgent;
 import android.app.backup.FullBackup;
 import android.app.backup.FullBackupDataOutput;
 import android.content.Context;
+import android.os.Environment;
 import android.os.ParcelFileDescriptor;
 import android.os.storage.StorageManager;
 import android.os.storage.StorageVolume;
@@ -11,6 +12,7 @@ import android.util.Slog;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.HashSet;
 
 public class SharedStorageAgent extends FullBackupAgent {
     static final String TAG = "SharedStorageAgent";
@@ -38,13 +40,20 @@ public class SharedStorageAgent extends FullBackupAgent {
         // "primary" shared storage volume is first in the list.
         if (mVolumes != null) {
             if (DEBUG) Slog.i(TAG, "Backing up " + mVolumes.length + " shared volumes");
+            // Ignore all apps' getExternalFilesDir() content; it is backed up as part of
+            // each app-specific payload.
+            HashSet<String> externalFilesDirFilter = new HashSet<String>();
+            final File externalAndroidRoot = new File(Environment.getExternalStorageDirectory(),
+                    Environment.DIRECTORY_ANDROID);
+            externalFilesDirFilter.add(externalAndroidRoot.getCanonicalPath());
+
             for (int i = 0; i < mVolumes.length; i++) {
                 StorageVolume v = mVolumes[i];
                 // Express the contents of volume N this way in the tar stream:
                 //     shared/N/path/to/file
                 // The restore will then extract to the given volume
                 String domain = FullBackup.SHARED_PREFIX + i;
-                fullBackupFileTree(null, domain, v.getPath(), null, output);
+                fullBackupFileTree(null, domain, v.getPath(), externalFilesDirFilter, output);
             }
         }
     }