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Commit 61f2d638 authored by Christopher Tate's avatar Christopher Tate
Browse files

Apply restored wallpaper via API rather than rename-into-place 

This plays nicer with SELinux and generally means we can be more robust
about file security policies.

Bug 28403975

Change-Id: I857ee7073c0090c7515421f41c9334025e25bc79
parent 68d180bb

packages/WallpaperBackup/src/com/android/wallpaperbackup/WallpaperBackupAgent.java

+56 −15
Original line number Original line Diff line number Diff line
@@ -22,22 +22,28 @@ import android.app.backup.BackupDataInput; 
import android.app.backup.BackupDataOutput;

import android.app.backup.BackupDataOutput;

import android.app.backup.FullBackupDataOutput;

import android.app.backup.FullBackupDataOutput;

import android.content.Context;

import android.content.Context;

import android.graphics.Rect;

import android.os.Environment;

import android.os.Environment;

import android.os.ParcelFileDescriptor;

import android.os.ParcelFileDescriptor;

import android.os.UserHandle;

import android.os.UserHandle;

import android.system.Os;

import android.system.Os;

import android.util.Slog;

import android.util.Slog;

import android.util.Xml;



import org.xmlpull.v1.XmlPullParser;





import java.io.File;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.IOException;

import java.nio.charset.StandardCharsets;





public class WallpaperBackupAgent extends BackupAgent {

public class WallpaperBackupAgent extends BackupAgent {

    private static final String TAG = "WallpaperBackup";

    private static final String TAG = "WallpaperBackup";

    private static final boolean DEBUG = false;

    private static final boolean DEBUG = false;





    // NB: must be kept in sync with WallpaperManagerService but has no

    // NB: must be kept in sync with WallpaperManagerService but has no

    // compile-time visiblity.

    // compile-time visibility.





    // Target filenames within the system's wallpaper directory

    // Target filenames within the system's wallpaper directory

    static final String WALLPAPER = "wallpaper_orig";

    static final String WALLPAPER = "wallpaper_orig";
@@ -107,11 +113,7 @@ public class WallpaperBackupAgent extends BackupAgent { 
    }

    }





    // We use the default onRestoreFile() implementation that will recreate our stage files,

    // We use the default onRestoreFile() implementation that will recreate our stage files,

    // then postprocess in onRestoreFinished() to move them on top of the live data.

    // then post-process in onRestoreFinished() to apply the new wallpaper.

    //

    // NOTE: this relies on our local files dir being on the same filesystem as the live

    // system wallpaper data.  If this is not the case then an actual copy operation will

    // be needed.

    @Override

    @Override

    public void onRestoreFinished() {

    public void onRestoreFinished() {

        if (DEBUG) {

        if (DEBUG) {
@@ -125,19 +127,25 @@ public class WallpaperBackupAgent extends BackupAgent { 
            // to back up the original image on the source device.

            // to back up the original image on the source device.

            if (imageStage.exists()) {

            if (imageStage.exists()) {

                if (DEBUG) {

                if (DEBUG) {

                    Slog.v(TAG, "Got restored wallpaper; renaming into place");

                    Slog.v(TAG, "Got restored wallpaper; applying");

                }



                // Parse the restored info file to find the crop hint.  Note that this currently

                // relies on a priori knowledge of the wallpaper info file schema.

                Rect cropHint = parseCropHint(infoStage);

                if (cropHint != null) {

                    if (DEBUG) {

                        Slog.v(TAG, "Restored crop hint " + cropHint + "; now writing data");

                    }

                    WallpaperManager wm = getSystemService(WallpaperManager.class);

                    try (FileInputStream in = new FileInputStream(imageStage)) {

                        wm.setStream(in, cropHint, true, WallpaperManager.FLAG_SYSTEM);

                    } finally {} // auto-closes 'in'

                }

                }

                // Rename the image file into place last because that is the trigger for

                // the wallpaper observer to generate a new crop/scale

                Os.rename(infoStage.getCanonicalPath(), mWallpaperInfo.getCanonicalPath());

                Os.rename(imageStage.getCanonicalPath(), mWallpaperFile.getCanonicalPath());

            }

            }

        } catch (Exception e) {

        } catch (Exception e) {

            Slog.e(TAG, "Unable to restore wallpaper: " + e.getMessage());

            Slog.e(TAG, "Unable to restore wallpaper: " + e.getMessage());

            mWm.clearWallpaper(WallpaperManager.FLAG_SYSTEM, UserHandle.USER_SYSTEM);

        } finally {

        } finally {

            // These "should" not exist because of the renames, but make sure

            // in case of errors/exceptions/etc.

            if (DEBUG) {

            if (DEBUG) {

                Slog.v(TAG, "Removing restore stage files");

                Slog.v(TAG, "Removing restore stage files");

            }

            }
@@ -146,8 +154,41 @@ public class WallpaperBackupAgent extends BackupAgent { 
        }

        }

    }

    }





    private Rect parseCropHint(File wallpaperInfo) {

        Rect cropHint = new Rect();

        try (FileInputStream stream = new FileInputStream(wallpaperInfo)) {

            XmlPullParser parser = Xml.newPullParser();

            parser.setInput(stream, StandardCharsets.UTF_8.name());



            int type;

            do {

                type = parser.next();

                if (type == XmlPullParser.START_TAG) {

                    String tag = parser.getName();

                    if ("wp".equals(tag)) {

                        cropHint.left = getAttributeInt(parser, "cropLeft", 0);

                        cropHint.top = getAttributeInt(parser, "cropTop", 0);

                        cropHint.right = getAttributeInt(parser, "cropRight", 0);

                        cropHint.bottom = getAttributeInt(parser, "cropBottom", 0);

                    }

                }

            } while (type != XmlPullParser.END_DOCUMENT);

        } catch (Exception e) {

            // Whoops; can't process the info file at all.  Report failure.

            Slog.w(TAG, "Failed to parse restored metadata: " + e.getMessage());

            return null;

        }



        return cropHint;

    }



    private int getAttributeInt(XmlPullParser parser, String name, int defValue) {

        final String value = parser.getAttributeValue(null, name);

        return (value == null) ? defValue : Integer.parseInt(value);

    }



    //

    //

    // Key/value API: abstract, so required, but not used

    // Key/value API: abstract, therefore required; but not used

    //

    //





    @Override

    @Override