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Commit 64f10efa authored by Christopher Tate's avatar Christopher Tate Committed by Christopher Tate
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Track enable/disable of transport components 

For fallback / rollback of backup transport selection we need to
handle live enable/disable of legacy or superseded transports.
We now watch for component enable state changes in packages that
host transports, and rebind as needed.

The semantics for selecting the current transport have also been
adjusted.  We no longer require that the selected transport be
live and currently bound in order to be designated as the active
instance.  This prevents nondeterministic races around upgrade
and replacement.

Bug 17136637

Change-Id: Idaf45cf4522a23576444e6b11626ee3f7f47c36c
parent 48766577

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

+60 −31
Original line number Diff line number Diff line
@@ -1234,6 +1234,7 @@ public class BackupManagerService extends IBackupManager.Stub { 
        IntentFilter filter = new IntentFilter();

        filter.addAction(Intent.ACTION_PACKAGE_ADDED);

        filter.addAction(Intent.ACTION_PACKAGE_REMOVED);

        filter.addAction(Intent.ACTION_PACKAGE_CHANGED);

        filter.addDataScheme("package");

        mContext.registerReceiver(mBroadcastReceiver, filter);

        // Register for events related to sdcard installation.
@@ -1688,11 +1689,12 @@ public class BackupManagerService extends IBackupManager.Stub { 
            String action = intent.getAction();

            boolean replacing = false;

            boolean added = false;

            boolean rebind = false;

            boolean changed = false;

            Bundle extras = intent.getExtras();

            String pkgList[] = null;

            if (Intent.ACTION_PACKAGE_ADDED.equals(action) ||

                    Intent.ACTION_PACKAGE_REMOVED.equals(action)) {

                    Intent.ACTION_PACKAGE_REMOVED.equals(action) ||

                    Intent.ACTION_PACKAGE_CHANGED.equals(action)) {

                Uri uri = intent.getData();

                if (uri == null) {

                    return;
@@ -1701,7 +1703,43 @@ public class BackupManagerService extends IBackupManager.Stub { 
                if (pkgName != null) {

                    pkgList = new String[] { pkgName };

                }

                rebind = added = Intent.ACTION_PACKAGE_ADDED.equals(action);

                changed = Intent.ACTION_PACKAGE_CHANGED.equals(action);



                // At package-changed we only care about looking at new transport states

                if (changed) {

                    try {

                        if (MORE_DEBUG) {

                            Slog.i(TAG, "Package " + pkgName + " changed; rechecking");

                        }

                        // unbind existing possibly-stale connections to that package's transports

                        synchronized (mTransports) {

                            TransportConnection conn = mTransportConnections.get(pkgName);

                            if (conn != null) {

                                final ServiceInfo svc = conn.mTransport;

                                ComponentName svcName =

                                        new ComponentName(svc.packageName, svc.name);

                                String flatName = svcName.flattenToShortString();

                                Slog.i(TAG, "Unbinding " + svcName);



                                mContext.unbindService(conn);

                                mTransportConnections.remove(pkgName);

                                mTransports.remove(mTransportNames.get(flatName));

                                mTransportNames.remove(flatName);

                            }

                        }

                        // and then (re)bind as appropriate

                        PackageInfo app = mPackageManager.getPackageInfo(pkgName, 0);

                        checkForTransportAndBind(app);

                    } catch (NameNotFoundException e) {

                        // Nope, can't find it - just ignore

                        if (MORE_DEBUG) {

                            Slog.w(TAG, "Can't find changed package " + pkgName);

                        }

                    }

                    return; // nothing more to do in the PACKAGE_CHANGED case

                }



                added = Intent.ACTION_PACKAGE_ADDED.equals(action);

                replacing = extras.getBoolean(Intent.EXTRA_REPLACING, false);

            } else if (Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE.equals(action)) {

                added = true;
@@ -1737,11 +1775,10 @@ public class BackupManagerService extends IBackupManager.Stub { 


                        // Transport maintenance: rebind to known existing transports that have

                        // just been updated; and bind to any newly-installed transport services.

                        if (rebind) {

                            synchronized (mTransportConnections) {

                        synchronized (mTransports) {

                            final TransportConnection conn = mTransportConnections.get(packageName);

                            if (conn != null) {

                                    if (DEBUG) {

                                if (MORE_DEBUG) {

                                    Slog.i(TAG, "Transport package changed; rebinding");

                                }

                                bindTransport(conn.mTransport);
@@ -1749,7 +1786,6 @@ public class BackupManagerService extends IBackupManager.Stub { 
                                checkForTransportAndBind(app);

                            }

                        }

                        }



                    } catch (NameNotFoundException e) {

                        // doesn't really exist; ignore it
@@ -1840,7 +1876,7 @@ public class BackupManagerService extends IBackupManager.Stub { 
        intent.setComponent(svcName);



        TransportConnection connection;

        synchronized (mTransportConnections) {

        synchronized (mTransports) {

            connection = mTransportConnections.get(transport.packageName);

            if (null == connection) {

                connection = new TransportConnection(transport);
@@ -8462,31 +8498,24 @@ if (MORE_DEBUG) Slog.v(TAG, " + got " + nRead + "; now wanting " + (size - soF 
        return list;

    }



    // Select which transport to use for the next backup operation.  If the given

    // name is not one of the available transports, no action is taken and the method

    // returns null.

    // Select which transport to use for the next backup operation.

    public String selectBackupTransport(String transport) {

        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,

                "selectBackupTransport");



        synchronized (mTransports) {

            String prevTransport = null;

            if (mTransports.get(transport) != null) {

            final long oldId = Binder.clearCallingIdentity();

            try {

                    prevTransport = mCurrentTransport;

                String prevTransport = mCurrentTransport;

                mCurrentTransport = transport;

                Settings.Secure.putString(mContext.getContentResolver(),

                        Settings.Secure.BACKUP_TRANSPORT, transport);

                } finally {

                    Binder.restoreCallingIdentity(oldId);

                }

                Slog.v(TAG, "selectBackupTransport() set " + mCurrentTransport

                        + " returning " + prevTransport);

            } else {

                Slog.w(TAG, "Attempt to select unavailable transport " + transport);

            }

                return prevTransport;

            } finally {

                Binder.restoreCallingIdentity(oldId);

            }

        }

    }