diff --git a/services/java/com/android/server/pm/UserDetails.java b/services/java/com/android/server/pm/UserDetails.java
new file mode 100644
index 0000000..2aeed7c
--- /dev/null
+++ b/services/java/com/android/server/pm/UserDetails.java
@@ -0,0 +1,305 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.pm;
+
+import com.android.internal.util.FastXmlSerializer;
+
+import android.content.pm.UserInfo;
+import android.os.Environment;
+import android.os.FileUtils;
+import android.util.Slog;
+import android.util.SparseArray;
+import android.util.Xml;
+
+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.xmlpull.v1.XmlPullParser;
+import org.xmlpull.v1.XmlPullParserException;
+import org.xmlpull.v1.XmlSerializer;
+
+public class UserDetails {
+    private static final String TAG_NAME = "name";
+
+    private static final String ATTR_FLAGS = "flags";
+
+    private static final String ATTR_ID = "id";
+
+    private static final String TAG_USERS = "users";
+
+    private static final String TAG_USER = "user";
+
+    private static final String TAG = "UserDetails";
+
+    private static final String USER_INFO_DIR = "system/users";
+    private static final String USER_LIST_FILENAME = "userlist.xml";
+
+    private SparseArray<UserInfo> mUsers;
+
+    private final File mUsersDir;
+    private final File mUserListFile;
+
+    /**
+     * Available for testing purposes.
+     */
+    UserDetails(File dataDir) {
+        mUsersDir = new File(dataDir, USER_INFO_DIR);
+        mUsersDir.mkdirs();
+        FileUtils.setPermissions(mUsersDir.toString(),
+                FileUtils.S_IRWXU|FileUtils.S_IRWXG
+                |FileUtils.S_IROTH|FileUtils.S_IXOTH,
+                -1, -1);
+        mUserListFile = new File(mUsersDir, USER_LIST_FILENAME);
+        readUserList();
+    }
+
+    public UserDetails() {
+        this(Environment.getDataDirectory());
+    }
+
+    public List<UserInfo> getUsers() {
+        ArrayList<UserInfo> users = new ArrayList<UserInfo>(mUsers.size());
+        for (int i = 0; i < mUsers.size(); i++) {
+            users.add(mUsers.valueAt(i));
+        }
+        return users;
+    }
+
+    private void readUserList() {
+        mUsers = new SparseArray<UserInfo>();
+        if (!mUserListFile.exists()) {
+            fallbackToSingleUser();
+            return;
+        }
+        FileInputStream fis = null;
+        try {
+            fis = new FileInputStream(mUserListFile);
+            XmlPullParser parser = Xml.newPullParser();
+            parser.setInput(fis, null);
+            int type;
+            while ((type = parser.next()) != XmlPullParser.START_TAG
+                    && type != XmlPullParser.END_DOCUMENT) {
+                ;
+            }
+
+            if (type != XmlPullParser.START_TAG) {
+                Slog.e(TAG, "Unable to read user list");
+                fallbackToSingleUser();
+                return;
+            }
+
+            while ((type = parser.next()) != XmlPullParser.END_DOCUMENT) {
+                if (type == XmlPullParser.START_TAG && parser.getName().equals(TAG_USER)) {
+                    String id = parser.getAttributeValue(null, ATTR_ID);
+                    UserInfo user = readUser(Integer.parseInt(id));
+                    if (user != null) {
+                        mUsers.put(user.id, user);
+                    }
+                }
+            }
+        } catch (IOException ioe) {
+            fallbackToSingleUser();
+        } catch (XmlPullParserException pe) {
+            fallbackToSingleUser();
+        }
+    }
+
+    private void fallbackToSingleUser() {
+        // Create the primary user
+        UserInfo primary = new UserInfo(0, "Primary",
+                UserInfo.FLAG_ADMIN | UserInfo.FLAG_PRIMARY);
+        mUsers.put(0, primary);
+
+        writeUserList();
+        writeUser(primary);
+    }
+
+    /*
+     * Writes the user file in this format:
+     *
+     * <user flags="20039023" id="0">
+     *   <name>Primary</name>
+     * </user>
+     */
+    private void writeUser(UserInfo userInfo) {
+        try {
+            final File mUserFile = new File(mUsersDir, userInfo.id + ".xml");
+            final FileOutputStream fos = new FileOutputStream(mUserFile);
+            final BufferedOutputStream bos = new BufferedOutputStream(fos);
+
+            // XmlSerializer serializer = XmlUtils.serializerInstance();
+            final XmlSerializer serializer = new FastXmlSerializer();
+            serializer.setOutput(bos, "utf-8");
+            serializer.startDocument(null, true);
+            serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
+
+            serializer.startTag(null, TAG_USER);
+            serializer.attribute(null, ATTR_ID, Integer.toString(userInfo.id));
+            serializer.attribute(null, ATTR_FLAGS, Integer.toString(userInfo.flags));
+
+            serializer.startTag(null, TAG_NAME);
+            serializer.text(userInfo.name);
+            serializer.endTag(null, TAG_NAME);
+
+            serializer.endTag(null, TAG_USER);
+
+            serializer.endDocument();
+        } catch (IOException ioe) {
+            Slog.e(TAG, "Error writing user info " + userInfo.id + "\n" + ioe);
+        }
+    }
+
+    /*
+     * Writes the user list file in this format:
+     *
+     * <users>
+     *   <user id="0"></user>
+     *   <user id="2"></user>
+     * </users>
+     */
+    private void writeUserList() {
+        try {
+            final FileOutputStream fos = new FileOutputStream(mUserListFile);
+            final BufferedOutputStream bos = new BufferedOutputStream(fos);
+
+            // XmlSerializer serializer = XmlUtils.serializerInstance();
+            final XmlSerializer serializer = new FastXmlSerializer();
+            serializer.setOutput(bos, "utf-8");
+            serializer.startDocument(null, true);
+            serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
+
+            serializer.startTag(null, TAG_USERS);
+
+            for (int i = 0; i < mUsers.size(); i++) {
+                UserInfo user = mUsers.valueAt(i);
+                serializer.startTag(null, TAG_USER);
+                serializer.attribute(null, ATTR_ID, Integer.toString(user.id));
+                serializer.endTag(null, TAG_USER);
+                Slog.e(TAG, "Wrote user " + user.id + " to userlist.xml");
+            }
+
+            serializer.endTag(null, TAG_USERS);
+
+            serializer.endDocument();
+        } catch (IOException ioe) {
+            Slog.e(TAG, "Error writing user list");
+        }
+    }
+
+    private UserInfo readUser(int id) {
+        int flags = 0;
+        String name = null;
+
+        FileInputStream fis = null;
+        try {
+            File userFile = new File(mUsersDir, Integer.toString(id) + ".xml");
+            fis = new FileInputStream(userFile);
+            XmlPullParser parser = Xml.newPullParser();
+            parser.setInput(fis, null);
+            int type;
+            while ((type = parser.next()) != XmlPullParser.START_TAG
+                    && type != XmlPullParser.END_DOCUMENT) {
+                ;
+            }
+
+            if (type != XmlPullParser.START_TAG) {
+                Slog.e(TAG, "Unable to read user " + id);
+                return null;
+            }
+
+            if (type == XmlPullParser.START_TAG && parser.getName().equals(TAG_USER)) {
+                String storedId = parser.getAttributeValue(null, ATTR_ID);
+                if (Integer.parseInt(storedId) != id) {
+                    Slog.e(TAG, "User id does not match the file name");
+                    return null;
+                }
+                String flagString = parser.getAttributeValue(null, ATTR_FLAGS);
+                flags = Integer.parseInt(flagString);
+
+                while ((type = parser.next()) != XmlPullParser.START_TAG
+                        && type != XmlPullParser.END_DOCUMENT) {
+                }
+                if (type == XmlPullParser.START_TAG && parser.getName().equals(TAG_NAME)) {
+                    type = parser.next();
+                    if (type == XmlPullParser.TEXT) {
+                        name = parser.getText();
+                    }
+                }
+            }
+            fis.close();
+
+            UserInfo userInfo = new UserInfo(id, name, flags);
+            return userInfo;
+
+        } catch (IOException ioe) {
+        } catch (XmlPullParserException pe) {
+        }
+        return null;
+    }
+
+    public UserInfo createUser(String name, int flags) {
+        int id = getNextAvailableId();
+        UserInfo userInfo = new UserInfo(id, name, flags);
+        if (!createPackageFolders(id)) {
+            return null;
+        }
+        mUsers.put(id, userInfo);
+        writeUserList();
+        writeUser(userInfo);
+        return userInfo;
+    }
+
+    public void removeUser(int id) {
+        // Remove from the list
+        UserInfo userInfo = mUsers.get(id);
+        if (userInfo != null) {
+            // Remove this user from the list
+            mUsers.remove(id);
+            // Remove user file
+            File userFile = new File(mUsersDir, id + ".xml");
+            userFile.delete();
+            writeUserList();
+            removePackageFolders(id);
+        }
+    }
+
+    private int getNextAvailableId() {
+        int i = 0;
+        while (i < Integer.MAX_VALUE) {
+            if (mUsers.indexOfKey(i) < 0) {
+                break;
+            }
+            i++;
+        }
+        return i;
+    }
+
+    private boolean createPackageFolders(int id) {
+        // TODO: Create data directories for all the packages for a new user, w/ specified user id.
+        return true;
+    }
+
+    private boolean removePackageFolders(int id) {
+        // TODO: Remove all the data directories for the specified user.
+        return true;
+    }
+}