Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 3d9c19f2 authored by Eric Biggers's avatar Eric Biggers
Browse files

BrightnessTracker: don't create stuff directly in /data/system_de 

/data/system_de is only for per-user data; it *must* only contain
per-user encrypted directories.  Only vold should ever create anything
directly in this directory.  In preparation for removing system_server's
write access to this directory (https://r.android.com/2078213), make
BrightnessTracker store its brightness_events.xml file at
/data/system/brightness_events.xml instead of
/data/system_de/brightness_events.xml, and likewise for
ambient_brightness_stats.xml.

Migration happens lazily, except that the old files aren't ever deleted
since the SELinux policy will no longer allow system_server to do that;
the old files just stop being used.  vold will need to handle the
cleanup instead, or we could just leave the files around.

Test: Flashed new build without wiping userdata.  Log shows "Reading
      ambient_brightness_stats.xml from old location" as expected.
      Rebooted.  Log message no longer appears, as expected.  File
      /data/system/ambient_brightness_stats.xml exists, as expected.
Bug: 156305599
Change-Id: I6e0948ac54ec9183348943234d505e7466042963
parent 3c7a3e39

services/core/java/com/android/server/display/BrightnessTracker.java

+30 −2
Original line number Diff line number Diff line
@@ -505,12 +505,36 @@ public class BrightnessTracker { 
        }

    }



    // Return the path to the given file, either the new path

    // /data/system/$filename, or the old path /data/system_de/$filename if the

    // file exists there but not at the new path.  Only use this for EVENTS_FILE

    // and AMBIENT_BRIGHTNESS_STATS_FILE.

    //

    // Explanation: this service previously incorrectly stored these two files

    // directly in /data/system_de, instead of in /data/system where they should

    // have been.  As system_server no longer has write access to

    // /data/system_de itself, these files were moved to /data/system.  To

    // lazily migrate the files, we simply read from the old path if it exists

    // and the new one doesn't, and always write to the new path.  Note that

    // system_server doesn't have permission to delete the old files.

    private AtomicFile getFileWithLegacyFallback(String filename) {

        AtomicFile file = mInjector.getFile(filename);

        if (file != null && !file.exists()) {

            AtomicFile legacyFile = mInjector.getLegacyFile(filename);

            if (legacyFile != null && legacyFile.exists()) {

                Slog.i(TAG, "Reading " + filename + " from old location");

                return legacyFile;

            }

        }

        return file;

    }



    private void readEvents() {

        synchronized (mEventsLock) {

            // Read might prune events so mark as dirty.

            mEventsDirty = true;

            mEvents.clear();

            final AtomicFile readFrom = mInjector.getFile(EVENTS_FILE);

            final AtomicFile readFrom = getFileWithLegacyFallback(EVENTS_FILE);

            if (readFrom != null && readFrom.exists()) {

                FileInputStream input = null;

                try {
@@ -528,7 +552,7 @@ public class BrightnessTracker { 


    private void readAmbientBrightnessStats() {

        mAmbientBrightnessStatsTracker = new AmbientBrightnessStatsTracker(mUserManager, null);

        final AtomicFile readFrom = mInjector.getFile(AMBIENT_BRIGHTNESS_STATS_FILE);

        final AtomicFile readFrom = getFileWithLegacyFallback(AMBIENT_BRIGHTNESS_STATS_FILE);

        if (readFrom != null && readFrom.exists()) {

            FileInputStream input = null;

            try {
@@ -1095,6 +1119,10 @@ public class BrightnessTracker { 
        }



        public AtomicFile getFile(String filename) {

            return new AtomicFile(new File(Environment.getDataSystemDirectory(), filename));

        }



        public AtomicFile getLegacyFile(String filename) {

            return new AtomicFile(new File(Environment.getDataSystemDeDirectory(), filename));

        }

services/tests/servicestests/src/com/android/server/display/BrightnessTrackerTest.java

+6 −0
Original line number Diff line number Diff line
@@ -1036,6 +1036,12 @@ public class BrightnessTrackerTest { 
            return null;

        }



        @Override

        public AtomicFile getLegacyFile(String filename) {

            // Don't have the test write / read from anywhere.

            return null;

        }



        @Override

        public long currentTimeMillis() {

            return mCurrentTimeMillis;