/* PasswordFile.java -- 
   Copyright (C) 2003, 2006 Free Software Foundation, Inc.

This file is a part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at
your option) any later version.

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WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
USA

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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package gnu.javax.crypto.sasl.crammd5;

import gnu.javax.crypto.sasl.NoSuchUserException;
import gnu.javax.crypto.sasl.UserAlreadyExistsException;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;

/**
 * The CRAM-MD5 password file representation.
 */
public class PasswordFile
{

  // Constants and variables
  // -------------------------------------------------------------------------

  private static String DEFAULT_FILE;
  static
    {
      DEFAULT_FILE = System.getProperty(CramMD5Registry.PASSWORD_FILE,
                                        CramMD5Registry.DEFAULT_PASSWORD_FILE);
    }

  private HashMap entries;

  private File passwdFile;

  private long lastmod;

  // Constructor(s)
  // -------------------------------------------------------------------------

  public PasswordFile() throws IOException
  {
    this(DEFAULT_FILE);
  }

  public PasswordFile(final File pwFile) throws IOException
  {
    this(pwFile.getAbsolutePath());
  }

  public PasswordFile(final String fileName) throws IOException
  {
    passwdFile = new File(fileName);
    update();
  }

  // Class methods
  // -------------------------------------------------------------------------

  // Instance methods
  // -------------------------------------------------------------------------

  public synchronized void add(final String user, final String passwd,
                               final String[] attributes) throws IOException
  {
    checkCurrent(); // check if the entry exists
    if (entries.containsKey(user))
      {
        throw new UserAlreadyExistsException(user);
      }
    if (attributes.length != 5)
      {
        throw new IllegalArgumentException("Wrong number of attributes");
      }

    final String[] fields = new String[7]; // create the new entry
    fields[0] = user;
    fields[1] = passwd;
    System.arraycopy(attributes, 0, fields, 2, 5);
    entries.put(user, fields);
    savePasswd();
  }

  public synchronized void changePasswd(final String user, final String passwd)
      throws IOException
  {
    checkCurrent();
    if (!entries.containsKey(user))
      { // check if the entry exists
        throw new NoSuchUserException(user);
      }

    final String[] fields = (String[]) entries.get(user); // get the existing entry
    fields[1] = passwd; // modify the password field
    entries.remove(user); // delete the existing entry
    entries.put(user, fields); // add the new entry

    savePasswd();
  }

  public synchronized String[] lookup(final String user) throws IOException
  {
    checkCurrent();
    if (!entries.containsKey(user))
      {
        throw new NoSuchUserException(user);
      }
    return (String[]) entries.get(user);
  }

  public synchronized boolean contains(final String s) throws IOException
  {
    checkCurrent();

    return entries.containsKey(s);
  }

  private synchronized void update() throws IOException
  {
    lastmod = passwdFile.lastModified();
    readPasswd(new FileInputStream(passwdFile));
  }

  private void checkCurrent() throws IOException
  {
    if (passwdFile.lastModified() > lastmod)
      {
        update();
      }
  }

  private synchronized void readPasswd(final InputStream in) throws IOException
  {
    final BufferedReader din = new BufferedReader(new InputStreamReader(in));
    String line;
    entries = new HashMap();
    while ((line = din.readLine()) != null)
      {
        final String[] fields = new String[7];
        final StringTokenizer st = new StringTokenizer(line, ":", true);
        try
          {
            fields[0] = st.nextToken(); // username
            st.nextToken();

            fields[1] = st.nextToken(); // passwd
            if (fields[1].equals(":"))
              {
                fields[1] = "";
              }
            else
              {
                st.nextToken();
              }

            fields[2] = st.nextToken(); // uid
            if (fields[2].equals(":"))
              {
                fields[2] = "";
              }
            else
              {
                st.nextToken();
              }

            fields[3] = st.nextToken(); // gid
            if (fields[3].equals(":"))
              {
                fields[3] = "";
              }
            else
              {
                st.nextToken();
              }

            fields[4] = st.nextToken(); // gecos
            if (fields[4].equals(":"))
              {
                fields[4] = "";
              }
            else
              {
                st.nextToken();
              }

            fields[5] = st.nextToken(); // dir
            if (fields[5].equals(":"))
              {
                fields[5] = "";
              }
            else
              {
                st.nextToken();
              }

            fields[6] = st.nextToken(); // shell
            if (fields[6].equals(":"))
              {
                fields[6] = "";
              }
          }
        catch (NoSuchElementException x)
          {
            continue;
          }

        entries.put(fields[0], fields);
      }
  }

  private synchronized void savePasswd() throws IOException
  {
    if (passwdFile != null)
      {
        final FileOutputStream fos = new FileOutputStream(passwdFile);
        PrintWriter pw = null;
        try
          {
            pw = new PrintWriter(fos);
            String key;
            String[] fields;
            StringBuffer sb;
            int i;
            for (Iterator it = entries.keySet().iterator(); it.hasNext();)
              {
                key = (String) it.next();
                fields = (String[]) entries.get(key);
                sb = new StringBuffer(fields[0]);
                for (i = 1; i < fields.length; i++)
                  {
                    sb.append(":").append(fields[i]);
                  }
                pw.println(sb.toString());
              }
          }
        finally
          {
            if (pw != null)
              {
                try
                  {
                    pw.flush();
                  }
                finally
                  {
                    pw.close();
                  }
              }
            try
              {
                fos.close();
              }
            catch (IOException ignored)
              {
              }
            lastmod = passwdFile.lastModified();
          }
      }
  }
}