Introduce ephemeral users.

BUG: 24883058

Change-Id: I2e1d6aa184142c2a3dc0415c0cd407573453cf41
diff --git a/cmds/pm/src/com/android/commands/pm/Pm.java b/cmds/pm/src/com/android/commands/pm/Pm.java
index 544fd6a..478164a 100644
--- a/cmds/pm/src/com/android/commands/pm/Pm.java
+++ b/cmds/pm/src/com/android/commands/pm/Pm.java
@@ -16,11 +16,11 @@
 
 package com.android.commands.pm;
 
-import static android.content.pm.PackageManager.INTENT_FILTER_DOMAIN_VERIFICATION_STATUS_UNDEFINED;
-import static android.content.pm.PackageManager.INTENT_FILTER_DOMAIN_VERIFICATION_STATUS_ASK;
 import static android.content.pm.PackageManager.INTENT_FILTER_DOMAIN_VERIFICATION_STATUS_ALWAYS;
 import static android.content.pm.PackageManager.INTENT_FILTER_DOMAIN_VERIFICATION_STATUS_ALWAYS_ASK;
+import static android.content.pm.PackageManager.INTENT_FILTER_DOMAIN_VERIFICATION_STATUS_ASK;
 import static android.content.pm.PackageManager.INTENT_FILTER_DOMAIN_VERIFICATION_STATUS_NEVER;
+import static android.content.pm.PackageManager.INTENT_FILTER_DOMAIN_VERIFICATION_STATUS_UNDEFINED;
 
 import android.accounts.IAccountManager;
 import android.app.ActivityManager;
@@ -798,6 +798,10 @@
                 flags |= UserInfo.FLAG_MANAGED_PROFILE;
             } else if ("--restricted".equals(opt)) {
                 flags |= UserInfo.FLAG_RESTRICTED;
+            } else if ("--ephemeral".equals(opt)) {
+                flags |= UserInfo.FLAG_EPHEMERAL;
+            } else if ("--guest".equals(opt)) {
+                flags |= UserInfo.FLAG_GUEST;
             } else {
                 System.err.println("Error: unknown option " + opt);
                 return showUsage();
@@ -1356,7 +1360,7 @@
         System.err.println("       pm get-install-location");
         System.err.println("       pm set-permission-enforced PERMISSION [true|false]");
         System.err.println("       pm trim-caches DESIRED_FREE_SPACE [internal|UUID]");
-        System.err.println("       pm create-user [--profileOf USER_ID] [--managed] [--restricted] USER_NAME");
+        System.err.println("       pm create-user [--profileOf USER_ID] [--managed] [--restricted] [--ephemeral] [--guest] USER_NAME");
         System.err.println("       pm remove-user USER_ID");
         System.err.println("       pm get-max-users");
         System.err.println("");
diff --git a/core/java/android/content/pm/UserInfo.java b/core/java/android/content/pm/UserInfo.java
index 6e09595..e3050fe 100644
--- a/core/java/android/content/pm/UserInfo.java
+++ b/core/java/android/content/pm/UserInfo.java
@@ -78,6 +78,12 @@
 
     public static final int FLAG_QUIET_MODE = 0x00000080;
 
+    /**
+     * Indicates that this user is ephemeral. I.e. the user will be removed after leaving
+     * the foreground.
+     */
+    public static final int FLAG_EPHEMERAL = 0x00000100;
+
     public static final int NO_PROFILE_GROUP_ID = UserHandle.USER_NULL;
 
     public int id;
@@ -134,6 +140,11 @@
     public boolean isQuietModeEnabled() {
         return (flags & FLAG_QUIET_MODE) == FLAG_QUIET_MODE;
     }
+
+    public boolean isEphemeral() {
+        return (flags & FLAG_EPHEMERAL) == FLAG_EPHEMERAL;
+    }
+
     /**
      * Returns true if the user is a split system user.
      * <p>If {@link UserManager#isSplitSystemUser split system user mode} is not enabled,
diff --git a/core/java/android/os/UserManager.java b/core/java/android/os/UserManager.java
index c96305e..c8abcef 100644
--- a/core/java/android/os/UserManager.java
+++ b/core/java/android/os/UserManager.java
@@ -721,6 +721,25 @@
     }
 
     /**
+     * Checks if the calling app is running as an ephemeral user.
+     *
+     * @return whether the caller is an ephemeral user.
+     * @hide
+     */
+    public boolean isEphemeralUser() {
+        return isUserEphemeral(UserHandle.myUserId());
+    }
+
+    /**
+     * Returns whether the specified user is ephemeral.
+     * @hide
+     */
+    public boolean isUserEphemeral(int userId) {
+        final UserInfo user = getUserInfo(userId);
+        return user != null && user.isEphemeral();
+    }
+
+    /**
      * Return whether the given user is actively running.  This means that
      * the user is in the "started" state, not "stopped" -- it is currently
      * allowed to run code through scheduled alarms, receiving broadcasts,
diff --git a/core/java/android/os/storage/IMountService.java b/core/java/android/os/storage/IMountService.java
index c6510f0..9b3f02d 100644
--- a/core/java/android/os/storage/IMountService.java
+++ b/core/java/android/os/storage/IMountService.java
@@ -25,8 +25,6 @@
 import android.os.Parcelable;
 import android.os.RemoteException;
 
-import java.io.FileDescriptor;
-
 /**
  * WARNING! Update IMountService.h and IMountService.cpp if you change this
  * file. In particular, the ordering of the methods below must match the
@@ -1202,13 +1200,15 @@
             }
 
             @Override
-            public void createUserKey(int userId, int serialNumber) throws RemoteException {
+            public void createUserKey(int userId, int serialNumber, boolean ephemeral)
+                    throws RemoteException {
                 Parcel _data = Parcel.obtain();
                 Parcel _reply = Parcel.obtain();
                 try {
                     _data.writeInterfaceToken(DESCRIPTOR);
                     _data.writeInt(userId);
                     _data.writeInt(serialNumber);
+                    _data.writeInt(ephemeral ? 1 : 0);
                     mRemote.transact(Stub.TRANSACTION_createUserKey, _data, _reply, 0);
                     _reply.readException();
                 } finally {
@@ -1283,7 +1283,8 @@
             }
 
             @Override
-            public void prepareUserStorage(String volumeUuid, int userId, int serialNumber)
+            public void prepareUserStorage(
+                    String volumeUuid, int userId, int serialNumber, boolean ephemeral)
                     throws RemoteException {
                 Parcel _data = Parcel.obtain();
                 Parcel _reply = Parcel.obtain();
@@ -1292,6 +1293,7 @@
                     _data.writeString(volumeUuid);
                     _data.writeInt(userId);
                     _data.writeInt(serialNumber);
+                    _data.writeInt(ephemeral ? 1 : 0);
                     mRemote.transact(Stub.TRANSACTION_prepareUserStorage, _data, _reply, 0);
                     _reply.readException();
                 } finally {
@@ -2012,7 +2014,8 @@
                     data.enforceInterface(DESCRIPTOR);
                     int userId = data.readInt();
                     int serialNumber = data.readInt();
-                    createUserKey(userId, serialNumber);
+                    boolean ephemeral = data.readInt() != 0;
+                    createUserKey(userId, serialNumber, ephemeral);
                     reply.writeNoException();
                     return true;
                 }
@@ -2052,7 +2055,8 @@
                     String volumeUuid = data.readString();
                     int userId = data.readInt();
                     int serialNumber = data.readInt();
-                    prepareUserStorage(volumeUuid, userId, serialNumber);
+                    boolean ephemeral = data.readInt() != 0;
+                    prepareUserStorage(volumeUuid, userId, serialNumber, ephemeral);
                     reply.writeNoException();
                     return true;
                 }
@@ -2376,15 +2380,16 @@
     public void setPrimaryStorageUuid(String volumeUuid, IPackageMoveObserver callback)
             throws RemoteException;
 
-    public void createUserKey(int userId, int serialNumber) throws RemoteException;
+    public void createUserKey(int userId, int serialNumber, boolean ephemeral)
+            throws RemoteException;
     public void destroyUserKey(int userId) throws RemoteException;
 
     public void unlockUserKey(int userId, int serialNumber, byte[] token) throws RemoteException;
     public void lockUserKey(int userId) throws RemoteException;
     public boolean isUserKeyUnlocked(int userId) throws RemoteException;
 
-    public void prepareUserStorage(String volumeUuid, int userId, int serialNumber)
-            throws RemoteException;
+    public void prepareUserStorage(String volumeUuid, int userId, int serialNumber,
+            boolean ephemeral) throws RemoteException;
 
     public ParcelFileDescriptor mountAppFuse(String name) throws RemoteException;
 }
diff --git a/core/java/android/os/storage/StorageManager.java b/core/java/android/os/storage/StorageManager.java
index 7f36a98..beda169 100644
--- a/core/java/android/os/storage/StorageManager.java
+++ b/core/java/android/os/storage/StorageManager.java
@@ -966,9 +966,9 @@
     }
 
     /** {@hide} */
-    public void createUserKey(int userId, int serialNumber) {
+    public void createUserKey(int userId, int serialNumber, boolean ephemeral) {
         try {
-            mMountService.createUserKey(userId, serialNumber);
+            mMountService.createUserKey(userId, serialNumber, ephemeral);
         } catch (RemoteException e) {
             throw e.rethrowAsRuntimeException();
         }
@@ -1002,9 +1002,10 @@
     }
 
     /** {@hide} */
-    public void prepareUserStorage(String volumeUuid, int userId, int serialNumber) {
+    public void prepareUserStorage(
+            String volumeUuid, int userId, int serialNumber, boolean ephemeral) {
         try {
-            mMountService.prepareUserStorage(volumeUuid, userId, serialNumber);
+            mMountService.prepareUserStorage(volumeUuid, userId, serialNumber, ephemeral);
         } catch (RemoteException e) {
             throw e.rethrowAsRuntimeException();
         }
diff --git a/services/core/java/com/android/server/MountService.java b/services/core/java/com/android/server/MountService.java
index 473eff6..184f890 100644
--- a/services/core/java/com/android/server/MountService.java
+++ b/services/core/java/com/android/server/MountService.java
@@ -2716,12 +2716,13 @@
     }
 
     @Override
-    public void createUserKey(int userId, int serialNumber) {
+    public void createUserKey(int userId, int serialNumber, boolean ephemeral) {
         enforcePermission(android.Manifest.permission.STORAGE_INTERNAL);
         waitForReady();
 
         try {
-            mCryptConnector.execute("cryptfs", "create_user_key", userId, serialNumber);
+            mCryptConnector.execute("cryptfs", "create_user_key", userId, serialNumber,
+                ephemeral ? 1 : 0);
         } catch (NativeDaemonConnectorException e) {
             throw e.rethrowAsParcelableException();
         }
@@ -2797,13 +2798,14 @@
     }
 
     @Override
-    public void prepareUserStorage(String volumeUuid, int userId, int serialNumber) {
+    public void prepareUserStorage(
+            String volumeUuid, int userId, int serialNumber, boolean ephemeral) {
         enforcePermission(android.Manifest.permission.STORAGE_INTERNAL);
         waitForReady();
 
         try {
             mCryptConnector.execute("cryptfs", "prepare_user_storage", escapeNull(volumeUuid),
-                    userId, serialNumber);
+                    userId, serialNumber, ephemeral ? 1 : 0);
         } catch (NativeDaemonConnectorException e) {
             throw e.rethrowAsParcelableException();
         }
diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index d94e5f4..ab8e5a7 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -16450,7 +16450,7 @@
             if (userDir.exists()) continue;
 
             try {
-                sm.prepareUserStorage(volumeUuid, user.id, user.serialNumber);
+                sm.prepareUserStorage(volumeUuid, user.id, user.serialNumber, user.isEphemeral());
                 UserManagerService.enforceSerialNumber(userDir, user.serialNumber);
             } catch (IOException e) {
                 Log.wtf(TAG, "Failed to create user directory on " + volumeUuid, e);
diff --git a/services/core/java/com/android/server/pm/UserManagerService.java b/services/core/java/com/android/server/pm/UserManagerService.java
index e045758..4497e4d 100644
--- a/services/core/java/com/android/server/pm/UserManagerService.java
+++ b/services/core/java/com/android/server/pm/UserManagerService.java
@@ -306,13 +306,13 @@
     }
 
     void systemReady() {
-        // Prune out any partially created/partially removed users.
+        // Prune out any partially created, partially removed and ephemeral users.
         ArrayList<UserInfo> partials = new ArrayList<>();
         synchronized (mUsersLock) {
             final int userSize = mUsers.size();
             for (int i = 0; i < userSize; i++) {
                 UserInfo ui = mUsers.valueAt(i);
-                if ((ui.partial || ui.guestToRemove) && i != 0) {
+                if ((ui.partial || ui.guestToRemove || ui.isEphemeral()) && i != 0) {
                     partials.add(ui);
                 }
             }
@@ -1675,6 +1675,10 @@
                         }
                     }
                 }
+
+                if (parent != null && parent.isEphemeral()) {
+                    flags |= UserInfo.FLAG_EPHEMERAL;
+                }
                 userId = getNextAvailableId();
                 userInfo = new UserInfo(userId, name, null, flags);
                 userInfo.serialNumber = mNextSerialNumber++;
@@ -1703,12 +1707,13 @@
                 }
             }
             final StorageManager storage = mContext.getSystemService(StorageManager.class);
-            storage.createUserKey(userId, userInfo.serialNumber);
+            storage.createUserKey(userId, userInfo.serialNumber, userInfo.isEphemeral());
             for (VolumeInfo vol : storage.getWritablePrivateVolumes()) {
                 final String volumeUuid = vol.getFsUuid();
                 try {
                     final File userDir = Environment.getDataUserDirectory(volumeUuid, userId);
-                    storage.prepareUserStorage(volumeUuid, userId, userInfo.serialNumber);
+                    storage.prepareUserStorage(
+                            volumeUuid, userId, userInfo.serialNumber, userInfo.isEphemeral());
                     enforceSerialNumber(userDir, userInfo.serialNumber);
                 } catch (IOException e) {
                     Log.wtf(LOG_TAG, "Failed to create user directory on " + volumeUuid, e);