/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You 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 org.apache.catalina.startup;

import java.io.BufferedReader;

import java.io.FileReader;

import java.io.IOException;

import java.util.Hashtable;

import java.util.Enumeration;

/**

 * Concrete implementation of the <strong>UserDatabase</code> interface

 * that processes the <code>/etc/passwd</code> file on a Unix system.

 *

 * @author Craig R. McClanahan

 */

public final class PasswdUserDatabase

    implements UserDatabase {

    // --------------------------------------------------------- Constructors

    /**

     * Initialize a new instance of this user database component.

     */

    public PasswdUserDatabase() {

        super();

    }

    // --------------------------------------------------- Instance Variables

    /**

     * The pathname of the Unix password file.

     */

    private static final String PASSWORD_FILE = "/etc/passwd";

    /**

     * The set of home directories for all defined users, keyed by username.

     */

    private Hashtable homes = new Hashtable();

    /**

     * The UserConfig listener with which we are associated.

     */

    private UserConfig userConfig = null;

    // ----------------------------------------------------------- Properties

    /**

     * Return the UserConfig listener with which we are associated.

     */

    public UserConfig getUserConfig() {

        return (this.userConfig);

    }

    /**

     * Set the UserConfig listener with which we are associated.

     *

     * @param userConfig The new UserConfig listener

     */

    public void setUserConfig(UserConfig userConfig) {

        this.userConfig = userConfig;

        init();

    }

    // ------------------------------------------------------- Public Methods

    /**

     * Return an absolute pathname to the home directory for the specified user.

     *

     * @param user User for which a home directory should be retrieved

     */

    public String getHome(String user) {

        return ((String) homes.get(user));

    }

    /**

     * Return an enumeration of the usernames defined on this server.

     */

    public Enumeration getUsers() {

        return (homes.keys());

    }

    // ------------------------------------------------------ Private Methods

    /**

     * Initialize our set of users and home directories.

     */

    private void init() {

        BufferedReader reader = null;

        try {

            reader = new BufferedReader(new FileReader(PASSWORD_FILE));

            while (true) {

                // Accumulate the next line

                StringBuffer buffer = new StringBuffer();

                while (true) {

                    int ch = reader.read();

                    if ((ch < 0) || (ch == '\n'))

                        break;

                    buffer.append((char) ch);

                }

                String line = buffer.toString();

                if (line.length() < 1)

                    break;

                // Parse the line into constituent elements

                int n = 0;

                String tokens[] = new String[7];

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

                    tokens[i] = null;

                while (n < tokens.length) {

                    String token = null;

                    int colon = line.indexOf(':');

                    if (colon >= 0) {

                        token = line.substring(0, colon);

                        line = line.substring(colon + 1);

                    } else {

                        token = line;

                        line = "";

                    }

                    tokens[n++] = token;

                }

                // Add this user and corresponding directory

                if ((tokens[0] != null) && (tokens[5] != null))

                    homes.put(tokens[0], tokens[5]);

            }

            reader.close();

            reader = null;

        } catch (Exception e) {

            if (reader != null) {

                try {

                    reader.close();

                } catch (IOException f) {

                    ;

                }

                reader = null;

            }

        }

    }

}