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Commit 5af1835d authored by Jeff Sharkey's avatar Jeff Sharkey
Browse files

Generate stable MTP storage IDs. 

It ends up that MediaProvider is persisting MTP storage IDs in its
database, so we need to make sure we generate stable IDs over time,
otherwise we can end up looking into a black hole.

Bug: 22256092
Change-Id: I6a75c239aac1b71fd5f6df0df69b24971079a086
parent 7a788a86

core/java/android/os/storage/StorageVolume.java

+3 −0
Original line number Diff line number Diff line
@@ -58,6 +58,9 @@ public class StorageVolume implements Parcelable { 
    // ACTION_MEDIA_BAD_REMOVAL, ACTION_MEDIA_UNMOUNTABLE and ACTION_MEDIA_EJECT broadcasts.

    public static final String EXTRA_STORAGE_VOLUME = "storage_volume";



    public static final int STORAGE_ID_INVALID = 0x00000000;

    public static final int STORAGE_ID_PRIMARY = 0x00010001;



    public StorageVolume(String id, int storageId, File path, String description, boolean primary,

            boolean removable, boolean emulated, long mtpReserveSize, boolean allowMassStorage,

            long maxFileSize, UserHandle owner, String fsUuid, String state) {

core/java/android/os/storage/VolumeInfo.java

+33 −9
Original line number Diff line number Diff line
@@ -147,15 +147,11 @@ public class VolumeInfo implements Parcelable { 
    public String path;

    public String internalPath;



    /** Framework state */

    public final int mtpIndex;



    public VolumeInfo(String id, int type, DiskInfo disk, String partGuid, int mtpIndex) {

    public VolumeInfo(String id, int type, DiskInfo disk, String partGuid) {

        this.id = Preconditions.checkNotNull(id);

        this.type = type;

        this.disk = disk;

        this.partGuid = partGuid;

        this.mtpIndex = mtpIndex;

    }



    public VolumeInfo(Parcel parcel) {
@@ -175,7 +171,6 @@ public class VolumeInfo implements Parcelable { 
        fsLabel = parcel.readString();

        path = parcel.readString();

        internalPath = parcel.readString();

        mtpIndex = parcel.readInt();

    }



    public static @NonNull String getEnvironmentForState(int state) {
@@ -308,7 +303,6 @@ public class VolumeInfo implements Parcelable { 
        final boolean removable;

        final boolean emulated;

        final boolean allowMassStorage = false;

        final int mtpStorageId = MtpStorage.getStorageIdForIndex(mtpIndex);

        final String envState = getEnvironmentForState(state);



        File userPath = getPathForUser(userId);
@@ -326,9 +320,15 @@ public class VolumeInfo implements Parcelable { 


        long mtpReserveSize = 0;

        long maxFileSize = 0;

        int mtpStorageId = StorageVolume.STORAGE_ID_INVALID;



        if (type == TYPE_EMULATED) {

            emulated = true;



            if (isPrimary()) {

                mtpStorageId = StorageVolume.STORAGE_ID_PRIMARY;

            }



            mtpReserveSize = StorageManager.from(context).getStorageLowBytes(userPath);



            if (ID_EMULATED_INTERNAL.equals(id)) {
@@ -341,6 +341,14 @@ public class VolumeInfo implements Parcelable { 
            emulated = false;

            removable = true;



            if (isPrimary()) {

                mtpStorageId = StorageVolume.STORAGE_ID_PRIMARY;

            } else {

                // Since MediaProvider currently persists this value, we need a

                // value that is stable over time.

                mtpStorageId = buildStableMtpStorageId(fsUuid);

            }



            if ("vfat".equals(fsType)) {

                maxFileSize = 4294967295L;

            }
@@ -354,6 +362,24 @@ public class VolumeInfo implements Parcelable { 
                fsUuid, envState);

    }



    public static int buildStableMtpStorageId(String fsUuid) {

        if (TextUtils.isEmpty(fsUuid)) {

            return StorageVolume.STORAGE_ID_INVALID;

        } else {

            int hash = 0;

            for (int i = 0; i < fsUuid.length(); ++i) {

                hash = 31 * hash + fsUuid.charAt(i);

            }

            hash = (hash ^ (hash << 16)) & 0xffff0000;

            // Work around values that the spec doesn't allow, or that we've

            // reserved for primary

            if (hash == 0x00000000) hash = 0x00020000;

            if (hash == 0x00010000) hash = 0x00020000;

            if (hash == 0xffff0000) hash = 0xfffe0000;

            return hash | 0x0001;

        }

    }



    // TODO: avoid this layering violation

    private static final String DOCUMENT_AUTHORITY = "com.android.externalstorage.documents";

    private static final String DOCUMENT_ROOT_PRIMARY_EMULATED = "primary";
@@ -402,7 +428,6 @@ public class VolumeInfo implements Parcelable { 
        pw.println();

        pw.printPair("path", path);

        pw.printPair("internalPath", internalPath);

        pw.printPair("mtpIndex", mtpIndex);

        pw.decreaseIndent();

        pw.println();

    }
@@ -469,6 +494,5 @@ public class VolumeInfo implements Parcelable { 
        parcel.writeString(fsLabel);

        parcel.writeString(path);

        parcel.writeString(internalPath);

        parcel.writeInt(mtpIndex);

    }

}

media/java/android/mtp/MtpStorage.java

+0 −12
Original line number Diff line number Diff line
@@ -53,18 +53,6 @@ public class MtpStorage { 
        return mStorageId;

    }



    /**

     * Generates a storage ID for storage of given index.

     * Index 0 is for primary external storage

     *

     * @return the storage ID

     */

    public static int getStorageIdForIndex(int index) {

        // storage ID is 0x00010001 for primary storage,

        // then 0x00020001, 0x00030001, etc. for secondary storages

        return ((index + 1) << 16) + 1;

    }



   /**

     * Returns the file path for the storage unit's storage in the file system

     *

services/core/java/com/android/server/MountService.java

+3 −14
Original line number Diff line number Diff line
@@ -402,16 +402,6 @@ class MountService extends IMountService.Stub 
        }

    }



    private static int sNextMtpIndex = 1;



    private static int allocateMtpIndex(String volId) {

        if (VolumeInfo.ID_EMULATED_INTERNAL.equals(volId)) {

            return 0;

        } else {

            return sNextMtpIndex++;

        }

    }



    /** List of crypto types.

      * These must match CRYPT_TYPE_XXX in cryptfs.h AND their

      * corresponding commands in CommandListener.cpp */
@@ -742,7 +732,7 @@ class MountService extends IMountService.Stub 


            // Create a stub volume that represents internal storage

            final VolumeInfo internal = new VolumeInfo(VolumeInfo.ID_PRIVATE_INTERNAL,

                    VolumeInfo.TYPE_PRIVATE, null, null, 0);

                    VolumeInfo.TYPE_PRIVATE, null, null);

            internal.state = VolumeInfo.STATE_MOUNTED;

            internal.path = Environment.getDataDirectory().getAbsolutePath();

            mVolumes.put(internal.id, internal);
@@ -967,8 +957,7 @@ class MountService extends IMountService.Stub 
                final String partGuid = TextUtils.nullIfEmpty(cooked[4]);



                final DiskInfo disk = mDisks.get(diskId);

                final int mtpIndex = allocateMtpIndex(id);

                final VolumeInfo vol = new VolumeInfo(id, type, disk, partGuid, mtpIndex);

                final VolumeInfo vol = new VolumeInfo(id, type, disk, partGuid);

                mVolumes.put(id, vol);

                onVolumeCreatedLocked(vol);

                break;
@@ -2604,7 +2593,7 @@ class MountService extends IMountService.Stub 
            final String uuid = null;

            final String state = Environment.MEDIA_REMOVED;



            res.add(0, new StorageVolume(id, MtpStorage.getStorageIdForIndex(0), path,

            res.add(0, new StorageVolume(id, StorageVolume.STORAGE_ID_INVALID, path,

                    description, primary, removable, emulated, mtpReserveSize,

                    allowMassStorage, maxFileSize, owner, uuid, state));

        }