Add -nosystem flag to adb backup

This makes it easy to back up everything that belongs to 3rd party apps, but
nothing that comes with the system per se.  If any system packages are
explicitly named on the command line they will be included in the backup
even if -nosystem was passed.  So, for example, this will back up all 3rd
party apps as well as system settings, but nothing else belonging to
system-deployed apps:

   adb backup -all -nosystem com.android.provider.settings

Bug 5361503

Change-Id: Iebe04b7d7027ca58b9f55e8eb7f219d6cca69269

Author: Christopher Tate

cmds/bu/src/com/android/commands/bu/Backup.java

@@ -66,6 +66,7 @@ private void doFullBackup(int socketFd) {
         boolean saveApks = false;
         boolean saveShared = false;
         boolean doEverything = false;
+        boolean allIncludesSystem = true;
 
         String arg;
         while ((arg = nextArg()) != null) {
@@ -78,6 +79,10 @@ private void doFullBackup(int socketFd) {
                     saveShared = true;
                 } else if ("-noshared".equals(arg)) {
                     saveShared = false;
+                } else if ("-system".equals(arg)) {
+                    allIncludesSystem = true;
+                } else if ("-nosystem".equals(arg)) {
+                    allIncludesSystem = false;
                 } else if ("-all".equals(arg)) {
                     doEverything = true;
                 } else {
@@ -102,7 +107,7 @@ private void doFullBackup(int socketFd) {
         try {
             ParcelFileDescriptor fd = ParcelFileDescriptor.adoptFd(socketFd);
             String[] packArray = new String[packages.size()];
-            mBackupManager.fullBackup(fd, saveApks, saveShared, doEverything,
+            mBackupManager.fullBackup(fd, saveApks, saveShared, doEverything, allIncludesSystem,
                     packages.toArray(packArray));
         } catch (RemoteException e) {
             Log.e(TAG, "Unable to invoke backup manager for backup");

core/java/android/app/backup/IBackupManager.aidl

@@ -157,11 +157,15 @@ interface IBackupManager {
      * @param allApps If <code>true</code>, the resulting tar stream will include all
      *     installed applications' data, not just those named in the <code>packageNames</code>
      *     parameter.
+     * @param allIncludesSystem If {@code true}, then {@code allApps} will be interpreted
+     *     as including packages pre-installed as part of the system. If {@code false},
+     *     then setting {@code allApps} to {@code true} will mean only that all 3rd-party
+     *     applications will be included in the dataset.
      * @param packageNames The package names of the apps whose data (and optionally .apk files)
      *     are to be backed up.  The <code>allApps</code> parameter supersedes this.
      */
     void fullBackup(in ParcelFileDescriptor fd, boolean includeApks, boolean includeShared,
-            boolean allApps, in String[] packageNames);
+            boolean allApps, boolean allIncludesSystem, in String[] packageNames);
 
     /**
      * Restore device content from the data stream passed through the given socket.  The

services/java/com/android/server/BackupManagerService.java

@@ -325,14 +325,16 @@ class FullBackupParams extends FullParams {
         public boolean includeApks;
         public boolean includeShared;
         public boolean allApps;
+        public boolean includeSystem;
         public String[] packages;
 
         FullBackupParams(ParcelFileDescriptor output, boolean saveApks, boolean saveShared,
-                boolean doAllApps, String[] pkgList) {
+                boolean doAllApps, boolean doSystem, String[] pkgList) {
             fd = output;
             includeApks = saveApks;
             includeShared = saveShared;
             allApps = doAllApps;
+            includeSystem = doSystem;
             packages = pkgList;
         }
     }
@@ -504,7 +506,7 @@ public void handleMessage(Message msg) {
                 PerformFullBackupTask task = new PerformFullBackupTask(params.fd,
                         params.observer, params.includeApks,
                         params.includeShared, params.curPassword, params.encryptPassword,
-                        params.allApps, params.packages, params.latch);
+                        params.allApps, params.includeSystem, params.packages, params.latch);
                 (new Thread(task)).start();
                 break;
             }
@@ -2161,6 +2163,7 @@ class PerformFullBackupTask implements Runnable {
         boolean mIncludeApks;
         boolean mIncludeShared;
         boolean mAllApps;
+        final boolean mIncludeSystem;
         String[] mPackages;
         String mCurrentPassword;
         String mEncryptPassword;
@@ -2219,13 +2222,14 @@ public void run() {
 
         PerformFullBackupTask(ParcelFileDescriptor fd, IFullBackupRestoreObserver observer, 
                 boolean includeApks, boolean includeShared, String curPassword,
-                String encryptPassword, boolean doAllApps, String[] packages,
+                String encryptPassword, boolean doAllApps, boolean doSystem, String[] packages,
                 AtomicBoolean latch) {
             mOutputFile = fd;
             mObserver = observer;
             mIncludeApks = includeApks;
             mIncludeShared = includeShared;
             mAllApps = doAllApps;
+            mIncludeSystem = doSystem;
             mPackages = packages;
             mCurrentPassword = curPassword;
             // when backing up, if there is a current backup password, we require that
@@ -2245,7 +2249,7 @@ public void run() {
 
         @Override
         public void run() {
-            final List<PackageInfo> packagesToBackup;
+            List<PackageInfo> packagesToBackup = new ArrayList<PackageInfo>();
 
             Slog.i(TAG, "--- Performing full-dataset backup ---");
             sendStartBackup();
@@ -2254,8 +2258,23 @@ public void run() {
             if (mAllApps) {
                 packagesToBackup = mPackageManager.getInstalledPackages(
                         PackageManager.GET_SIGNATURES);
-            } else {
-                packagesToBackup = new ArrayList<PackageInfo>();
+                // Exclude system apps if we've been asked to do so
+                if (mIncludeSystem == false) {
+                    for (int i = 0; i < packagesToBackup.size(); ) {
+                        PackageInfo pkg = packagesToBackup.get(i);
+                        if ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) {
+                            packagesToBackup.remove(i);
+                        } else {
+                            i++;
+                        }
+                    }
+                }
+            }
+
+            // Now process the command line argument packages, if any. Note that explicitly-
+            // named system-partition packages will be included even if includeSystem was
+            // set to false.
+            if (mPackages != null) {
                 for (String pkgName : mPackages) {
                     try {
                         packagesToBackup.add(mPackageManager.getPackageInfo(pkgName,
@@ -2268,8 +2287,8 @@ public void run() {
 
             // Cull any packages that have indicated that backups are not permitted.
             for (int i = 0; i < packagesToBackup.size(); ) {
-                PackageInfo info = packagesToBackup.get(i);
-                if ((info.applicationInfo.flags & ApplicationInfo.FLAG_ALLOW_BACKUP) == 0) {
+                PackageInfo pkg = packagesToBackup.get(i);
+                if ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_ALLOW_BACKUP) == 0) {
                     packagesToBackup.remove(i);
                 } else {
                     i++;
@@ -4781,7 +4800,7 @@ boolean deviceIsProvisioned() {
     // to the supplied file descriptor.  This method is synchronous and does not return
     // to the caller until the backup has been completed.
     public void fullBackup(ParcelFileDescriptor fd, boolean includeApks, boolean includeShared,
-            boolean doAllApps, String[] pkgList) {
+            boolean doAllApps, boolean includeSystem, String[] pkgList) {
         mContext.enforceCallingPermission(android.Manifest.permission.BACKUP, "fullBackup");
 
         // Validate
@@ -4811,7 +4830,7 @@ public void fullBackup(ParcelFileDescriptor fd, boolean includeApks, boolean inc
             Slog.i(TAG, "Beginning full backup...");
 
             FullBackupParams params = new FullBackupParams(fd, includeApks, includeShared,
-                    doAllApps, pkgList);
+                    doAllApps, includeSystem, pkgList);
             final int token = generateToken();
             synchronized (mFullConfirmations) {
                 mFullConfirmations.put(token, params);