Merge "Enforce a user limit" into jb-mr1-dev

Author: Amith Yamasani

core/res/res/values/config.xml

@@ -923,5 +923,5 @@
     <bool name="config_syncstorageengine_masterSyncAutomatically">true</bool>
 
     <!--  Maximum number of supported users -->
-    <integer name="config_multiuserMaximumUsers">10</integer>
+    <integer name="config_multiuserMaximumUsers">1</integer>
 </resources>

services/java/com/android/server/pm/UserManagerService.java

@@ -237,6 +237,18 @@ public void wipeUser(int userHandle) {
         // TODO:
     }
 
+    /**
+     * Check if we've hit the limit of how many users can be created.
+     */
+    private boolean isUserLimitReached() {
+        synchronized (mInstallLock) {
+            int nUsers = mUsers.size();
+            int userLimit = mContext.getResources().getInteger(
+                    com.android.internal.R.integer.config_multiuserMaximumUsers);
+            return nUsers >= userLimit;
+        }
+    }
+
     /**
      * Enforces that only the system UID or root's UID or apps that have the
      * {@link android.Manifest.permission.MANAGE_USERS MANAGE_USERS}
@@ -522,6 +534,9 @@ private UserInfo readUser(int id) {
     @Override
     public UserInfo createUser(String name, int flags) {
         checkManageUsersPermission("Only the system can create users");
+
+        if (isUserLimitReached()) return null;
+
         int userId = getNextAvailableId();
         UserInfo userInfo = new UserInfo(userId, name, null, flags);
         File userPath = new File(mBaseUserPath, Integer.toString(userId));