Metacat

/**

 *  '$RCSfile$'

 *    Purpose: An implementation of the AuthInterface interface that

 *             allows Metacat to use the LDAP protocol for

 *             directory services

 *  Copyright: 2000 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Matt Jones

 *    Release: @release@

 *

 *   '$Author: tao $'

 *     '$Date: 2003-03-19 15:11:10 -0800 (Wed, 19 Mar 2003) $'

 * '$Revision: 1494 $'

 *

 * This program 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.

 *

 * This program is distributed in the hope that it will be useful,

 * but 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.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.metacat;

import java.net.ConnectException;

import javax.naming.AuthenticationException;

import javax.naming.Context;

import javax.naming.NamingEnumeration;

import javax.naming.NamingException;

import javax.naming.SizeLimitExceededException;

import javax.naming.InitialContext;

import javax.naming.directory.InvalidSearchFilterException;

import javax.naming.directory.Attribute;

import javax.naming.directory.Attributes;

import javax.naming.directory.BasicAttribute;

import javax.naming.directory.BasicAttributes;

import javax.naming.directory.DirContext;

import javax.naming.directory.InitialDirContext;

import javax.naming.directory.SearchResult;

import javax.naming.directory.SearchControls;

import javax.naming.ReferralException;

import javax.naming.ldap.*;

import java.util.Iterator;

import java.util.HashMap;

import java.util.Hashtable;

import java.util.Enumeration;

import java.util.Set;

import java.util.Vector;

/**

 * An implementation of the AuthInterface interface that

 * allows Metacat to use the LDAP protocol for directory services.

 * The LDAP authentication service is used to determine if a user 

 * is authenticated, and whether they are a member of a particular group.

 */

public class AuthLdap implements AuthInterface, Runnable {

  private MetaCatUtil util = new MetaCatUtil();

  private String ldapUrl;

  private String ldapsUrl;

  private String ldapBase;

  private String referral;

  private Context referralContext;

  Hashtable env = new Hashtable(11);

  private Context rContext;

  private String userName;

  private String userPassword;

  ReferralException refExc;

  String uid=null;

  /** 

   * Construct an AuthLdap

   */

  public AuthLdap() {

    // Read LDAP URI for directory service information

    this.ldapUrl = MetaCatUtil.getOption("ldapurl");

    this.ldapsUrl = MetaCatUtil.getOption("ldapsurl");

    this.ldapBase = MetaCatUtil.getOption("ldapbase");

    this.referral = MetaCatUtil.getOption("referral");

  }

  /**

   * Determine if a user/password are valid according to the authentication

   * service.

   *

   * @param user the name of the principal to authenticate

   * @param password the password to use for authentication

   * @returns boolean true if authentication successful, false otherwise

   */

  public boolean authenticate(String user, String password)

                    throws ConnectException

  {

    String ldapUrl = this.ldapUrl;

    String ldapsUrl = this.ldapsUrl;

    String ldapBase = this.ldapBase;

    boolean authenticated = false;

    String identifier = user;

    //get uid here.

    uid=user.substring(0, user.indexOf(","));

    try {

        // Check the usename as passed in

        authenticated = ldapAuthenticate(identifier, password);

        // if not found, try looking up a valid DN then auth again

        if (!authenticated) {

            MetaCatUtil.debugMessage("Looking up DN for: " + identifier, 35);

            identifier = getIdentifyingName(identifier,ldapUrl,ldapBase);

            //System.out.println("identifier: "+identifier);

            String refUrl = "";

            String refBase = "";

            if (identifier.startsWith("ldap")) {

                refUrl = identifier.substring(0,

                               identifier.lastIndexOf("/")+1);

                MetaCatUtil.debugMessage("Ref ldapUrl: " + refUrl, 35);

                int position = identifier.indexOf(",");

                int position2 = identifier.indexOf(",", position+1);

                refBase = identifier.substring(position2+1);

                MetaCatUtil.debugMessage("Ref ldapBase: " + refBase, 35);

                identifier = identifier.substring(

                             identifier.lastIndexOf("/")+1);

                MetaCatUtil.debugMessage("Trying: " + identifier, 35);

                authenticated = ldapAuthenticate(identifier, password,

                                                 refUrl, refBase);

            } else {

                identifier = identifier+","+ldapBase;

                MetaCatUtil.debugMessage("Trying: " + identifier, 35);

                authenticated = ldapAuthenticate(identifier, password);

            }

            //authenticated = ldapAuthenticate(identifier, password);

        }

    } catch (NullPointerException e) {

      util.debugMessage("NullPointerException b' password is null", 30);

      util.debugMessage("NullPointerException while authenticating in " + 

                        "AuthLdap.authenticate: " + e, 30);

      throw new ConnectException(

      "NullPointerException while authenticating in " + 

                        "AuthLdap.authenticate: " + e);

    } catch (NamingException e) {

      util.debugMessage("Naming exception while authenticating in " + 

                        "AuthLdap.authenticate: " + e, 30);

      e.printStackTrace();

    } catch (Exception e) {

      util.debugMessage(e.getMessage(), 30);

    }

    return authenticated;

  }

  /**

   * Connect to the LDAP directory and do the authentication using the

   * username and password as passed into the routine.

   *

   * @param identifier the distinguished name to check against LDAP

   * @param password the password for authentication

   */

  private boolean ldapAuthenticate(String identifier, String password)

            throws ConnectException, NamingException, NullPointerException

  {

      return ldapAuthenticate(identifier, password, 

                              this.ldapsUrl, this.ldapBase);

  }

  /**

   * Connect to the LDAP directory and do the authentication using the

   * username and password as passed into the routine.

   *

   * @param identifier the distinguished name to check against LDAP

   * @param password the password for authentication

   */

  private boolean ldapAuthenticate(String identifier, String password,

            String directoryUrl, String searchBase)

            throws ConnectException, NamingException, NullPointerException

  {

    double totStartTime = System.currentTimeMillis();

    boolean authenticated = false;

    if (identifier != null && !password.equals("")) 

    {

        //Pass the username and password to run() method

        userName=identifier;

        userPassword=password;

        // Identify service provider to use

        Hashtable env = new Hashtable(11);

        env.put(Context.INITIAL_CONTEXT_FACTORY, 

              "com.sun.jndi.ldap.LdapCtxFactory");

        env.put(Context.REFERRAL, "throw");

        env.put(Context.PROVIDER_URL, directoryUrl + searchBase);

        if ( !ldapsUrl.equals(ldapUrl) ) 

        {

          // ldap is set on default port 389

          // ldaps is set on second port - 636 by default

          //env.put(Context.SECURITY_PROTOCOL, "ssl");

        }

        env.put(Context.SECURITY_AUTHENTICATION, "simple");

        env.put(Context.SECURITY_PRINCIPAL, identifier);

        env.put(Context.SECURITY_CREDENTIALS, password);

        // If our auth credentials are invalid, an exception will be thrown

        DirContext ctx = null;

        try 

        {

          double startTime = System.currentTimeMillis();

          //Here to check the autheration

          ctx = new InitialDirContext(env);

          double stopTime = System.currentTimeMillis();

          util.debugMessage("Connection time thru " + ldapsUrl + " was: " +

                             (stopTime-startTime)/1000 + " seconds.", 35);

          authenticated = true;

          //tls.close();

          ctx.close();

          this.ldapUrl = ldapUrl;

          this.ldapBase = ldapBase;

          //break;

        } 

        catch (AuthenticationException ae) 

        {

          authenticated = false;

          if ( ctx != null ) 

          {

            ctx.close();

          }

        } 

        catch (javax.naming.InvalidNameException ine) 

        {

            util.debugMessage("An invalid DN was provided!", 30);

        } 

        catch (javax.naming.ReferralException re) 

        {

          util.debugMessage("referral during authentication", 30);

          util.debugMessage("Referral information: "+re.getReferralInfo(), 30);

          try

          {

            refExc = re;

            Thread t = new Thread(this);

            t.start();

            Thread.sleep(5000); //this is a manual override of ldap's 

                                //hideously long time out period.

            util.debugMessage("Awake after 5 seconds.", 35);

            if (referralContext == null)

            {

              t.interrupt();

              authenticated = false;

            }

            else

            {

              authenticated = true;

            }

          }

          catch (Exception e)

          {

            authenticated = false;

          }

        }

    } 

    else 

    { 

        util.debugMessage("User not found", 30);

    }

    double totStopTime = System.currentTimeMillis();

    util.debugMessage("total ldap authentication time: " + 

                      (totStopTime - totStartTime)/1000 + " seconds", 35);

    return authenticated;

  }

  /**

   * Get the identifying name for a given userid or name.  This is the name

   * that is used in conjunction withthe LDAP BaseDN to create a

   * distinguished name (dn) for the record

   *

   * @param user the user for which the identifying name is requested

   * @returns String the identifying name for the user, 

   *          or null if not found

   */

  private String getIdentifyingName(String user, String ldapUrl,

                                    String ldapBase) throws NamingException

  {

    String identifier = null;

    // Identify service provider to use

    Hashtable env = new Hashtable(11);

    env.put(Context.INITIAL_CONTEXT_FACTORY,

            "com.sun.jndi.ldap.LdapCtxFactory");

    util.debugMessage("setting referrals to: " + referral, 35);

    env.put(Context.REFERRAL, referral);

    env.put(Context.PROVIDER_URL, ldapUrl + ldapBase);

    //    non-secure LDAP context; dn are publicly readable

    try {

      // Bind to the LDAP server, in order to search for the right

      // distinguished name (dn) based on userid (uid) or common name (cn)

      DirContext ctx = new InitialDirContext(env);

      SearchControls ctls = new SearchControls();

      ctls.setSearchScope(SearchControls.SUBTREE_SCOPE);

      // Search for the user id or name using the uid, then cn and sn 

      //attributes

      // If we find a record, determine the dn for the record

      // The following blocks need to be refactored into a subroutine

      // they have a ridiculous amount of redundancy

      // Parse out the uid and org components and look up the real DN

      // This assumes a dn like "uid=x,o=y,dc=someinst,dc=org"

      int position = user.indexOf(",");

      String comp1 = user.substring(0, position);

      MetaCatUtil.debugMessage("First comp is: " + comp1, 35);

      String comp2 = user.substring(position+1, 

                                    user.indexOf(",", position+1));

      MetaCatUtil.debugMessage("Second comp is: " + comp2, 35);

      String filter = "(&(" + comp1 + ")(" + comp2 + "))";

      MetaCatUtil.debugMessage("Filter is: " + filter, 35);

      MetaCatUtil.debugMessage("Provider URL is: " + ldapUrl + ldapBase, 35);

      NamingEnumeration answer;

      try {

        answer = ctx.search("", filter, ctls);

        if (answer.hasMore()) {

          SearchResult sr = (SearchResult)answer.next();

          identifier = sr.getName();

          util.debugMessage("Originally Found: " + identifier, 35);

          return identifier;

        }

      } catch (InvalidSearchFilterException e) {}

      // That failed, so check if it is just a username

      filter = "(" + user + ")";

      try {

        answer = ctx.search("", filter, ctls);

        if (answer.hasMore()) {

          SearchResult sr = (SearchResult)answer.next();

          identifier = sr.getName();

          if ( !sr.isRelative() ) { 

            this.ldapUrl = identifier.substring(0,

                                                identifier.lastIndexOf("/")+1);

            this.ldapBase = identifier.substring(identifier.indexOf(",")+1);

            identifier = identifier.substring(identifier.lastIndexOf("/")+1,

                                              identifier.indexOf(","));

          }

          util.debugMessage("Found: " + identifier, 35);

          return identifier;

        }

      } catch (InvalidSearchFilterException e) {}

      // Maybe its a user id (uid)

      filter = "(uid=" + user + ")";

      answer = ctx.search("", filter, ctls);

      if (answer.hasMore()) {

        SearchResult sr = (SearchResult)answer.next();

        identifier = sr.getName();

        if ( !sr.isRelative() ) { 

          this.ldapUrl = identifier.substring(0,identifier.lastIndexOf("/")+1);

          this.ldapBase = identifier.substring(identifier.indexOf(",")+1);

          identifier = identifier.substring(identifier.lastIndexOf("/")+1,

                                            identifier.indexOf(","));

        }

        util.debugMessage("Found: " + identifier, 35);

      } else {

        // maybe its just a common name

        filter = "(cn=" + user + ")";

        NamingEnumeration answer2 = ctx.search("", filter, ctls);

        if (answer2.hasMore()) {

          SearchResult sr = (SearchResult)answer2.next();

          identifier = sr.getName();

          if ( !sr.isRelative() ) { 

            this.ldapUrl = identifier.substring(0,

                                                identifier.lastIndexOf("/")+1);

            this.ldapBase = identifier.substring(identifier.indexOf(",")+1);

            identifier = identifier.substring(identifier.lastIndexOf("/")+1,

                                              identifier.indexOf(","));

          }

          util.debugMessage("Found: " + identifier, 35);

        } else {

          // ok, last resort, is it a surname?

          filter = "(sn=" + user + ")";

          NamingEnumeration answer3 = ctx.search("", filter, ctls);

          if (answer3.hasMore()) {

            SearchResult sr = (SearchResult)answer3.next();

            identifier = sr.getName();

            if ( !sr.isRelative() ) { 

              this.ldapUrl = identifier.substring(0,

                                                identifier.lastIndexOf("/")+1);

              this.ldapBase = identifier.substring(identifier.indexOf(",")+1);

              identifier = identifier.substring(identifier.lastIndexOf("/")+1,

                                                identifier.indexOf(","));

            }

            util.debugMessage("Found: " + identifier, 35);

          }

        }

      }

      // Close the context when we're done the initial search

      ctx.close();

    } catch (NamingException e) {

      util.debugMessage("Naming exception while getting dn: " + e, 35);

      throw new NamingException(

      "Naming exception in AuthLdap.getIdentifyingName: " + e);

    }

    return identifier;

  }

  /**

   * Get all users from the authentication service

   *

   * @param user the user for authenticating against the service

   * @param password the password for authenticating against the service

   * @returns string array of all of the user names

   */

  public String[] getUsers(String user, String password) 

         throws ConnectException

  {

    String[] users = null;

    // Identify service provider to use

    Hashtable env = new Hashtable(11);

    env.put(Context.INITIAL_CONTEXT_FACTORY, 

            "com.sun.jndi.ldap.LdapCtxFactory");

    env.put(Context.REFERRAL, referral);

    env.put(Context.PROVIDER_URL, ldapUrl);

    try {

        // Create the initial directory context

        DirContext ctx = new InitialDirContext(env);

        // Specify the attributes to match.

        // Users are objects that have the attribute objectclass=InetOrgPerson.

        SearchControls ctls = new SearchControls();

        String[] attrIDs = {"dn"};

        ctls.setReturningAttributes(attrIDs);

        ctls.setSearchScope(SearchControls.SUBTREE_SCOPE);

        //ctls.setCountLimit(1000);

        String filter = "(objectClass=inetOrgPerson)";

        NamingEnumeration enum = ctx.search(ldapBase, filter, ctls);

        // Store the users in a vector

        Vector uvec = new Vector();

        try {

            while (enum.hasMore()) {

                SearchResult sr = (SearchResult)enum.next();

                uvec.add(sr.getName()+","+ldapBase);

            }

        } catch (SizeLimitExceededException slee) {

            util.debugMessage("LDAP Server size limit exceeded. " +

                    "Returning incomplete record set.", 35);

        }

        // initialize users[]; fill users[]

        users = new String[uvec.size()];

        for (int i=0; i < uvec.size(); i++) {

          users[i] = (String)uvec.elementAt(i); 

        }

        // Close the context when we're done

        ctx.close();

    } catch (NamingException e) {

      util.debugMessage("Problem getting users in AuthLdap.getUsers:" + e, 35);

      //e.printStackTrace(System.err);

      throw new ConnectException(

      "Problem getting users in AuthLdap.getUsers:" + e);

    }

    return users;

  }

  /**

   * Get the users for a particular group from the authentication service

   *

   * @param user the user for authenticating against the service

   * @param password the password for authenticating against the service

   * @param group the group whose user list should be returned

   * @returns string array of the user names belonging to the group

   */

  public String[] getUsers(String user, String password, String group) 

         throws ConnectException

  {

    String[] users = null;

    // Identify service provider to use

    Hashtable env = new Hashtable(11);

    env.put(Context.INITIAL_CONTEXT_FACTORY, 

            "com.sun.jndi.ldap.LdapCtxFactory");

    env.put(Context.REFERRAL, referral);

    env.put(Context.PROVIDER_URL, ldapUrl);

    try {

        // Create the initial directory context

        DirContext ctx = new InitialDirContext(env);

        // Specify the ids of the attributes to return

        String[] attrIDs = {"uniqueMember"};

        Attributes answer = ctx.getAttributes(group, attrIDs);

        Vector uvec = new Vector();

        try {

            for (NamingEnumeration ae = answer.getAll(); ae.hasMore();) {

                Attribute attr = (Attribute)ae.next();

                for (NamingEnumeration e = attr.getAll(); 

                     e.hasMore();

                     uvec.add(e.next()) 

                    );

            }

        } catch (SizeLimitExceededException slee) {

            util.debugMessage("LDAP Server size limit exceeded. " +

                    "Returning incomplete record set.", 35);

        }

        // initialize users[]; fill users[]

        users = new String[uvec.size()];

        for (int i=0; i < uvec.size(); i++) {

          users[i] = (String)uvec.elementAt(i); 

        }

        // Close the context when we're done

        ctx.close();

    } catch (NamingException e) {

      util.debugMessage("Problem getting users for a group in " +

              "AuthLdap.getUsers:" + e, 30);

      throw new ConnectException(

      "Problem getting users for a group in AuthLdap.getUsers:" + e);

    }

    return users;

  }

  /**

   * Get all groups from the authentication service

   *

   * @param user the user for authenticating against the service

   * @param password the password for authenticating against the service

   * @returns string array of the group names

   */

  public String[] getGroups(String user, String password) 

         throws ConnectException

  {

      return getGroups(user, password, null);

  }

  /**

   * Get the groups for a particular user from the authentication service

   *

   * @param user the user for authenticating against the service

   * @param password the password for authenticating against the service

   * @param foruser the user whose group list should be returned

   * @returns string array of the group names

   */

  public String[] getGroups(String user, String password, String foruser) 

         throws ConnectException

  {

    Vector uvec = new Vector();

    //Pass the username and password to run() method

    userName=user;

    userPassword=password;

    // Identify service provider to use

    env.put(Context.INITIAL_CONTEXT_FACTORY, 

            "com.sun.jndi.ldap.LdapCtxFactory");

    env.put(Context.REFERRAL, "throw");

    env.put(Context.PROVIDER_URL, ldapUrl);

    try {

        // Create the initial directory context

        DirContext ctx = new InitialDirContext(env);

        // Specify the ids of the attributes to return

        String[] attrIDs = {"cn"};

        // Specify the attributes to match.

        // Groups are objects with attribute objectclass=groupofuniquenames.

        // and have attribute uniquemember: uid=foruser,ldapbase.

        SearchControls ctls = new SearchControls();

        ctls.setReturningAttributes(attrIDs);

        ctls.setSearchScope(SearchControls.SUBTREE_SCOPE);

        String filter = null;

        String gfilter = "(objectClass=groupOfUniqueNames)";

        if (null == foruser) {

            filter = gfilter;

        } else {

            filter = "(& " + gfilter + "(uniqueMember=" + foruser + "))";

        }

        MetaCatUtil.debugMessage("searching for groups: " + filter, 35);

        NamingEnumeration enum = ctx.search(ldapBase, filter, ctls);

        // Print the groups

        MetaCatUtil.debugMessage("getting group results.", 50);

        while (enum.hasMore()) {

          SearchResult sr = (SearchResult)enum.next();          

          uvec.add(sr.getName()+","+ldapBase);

          MetaCatUtil.debugMessage("group " + sr.getName() + 

                                  " added to Group vector", 35);

        }

        // Close the context when we're done

        ctx.close();

    } 

    catch (ReferralException re) 

    {

      refExc = re;

      Thread t = new Thread(new GetGroup());

      util.debugMessage("Starting thread...", 50);

      t.start();

      util.debugMessage("sleeping for 5 seconds.", 50);

      try

      {

        Thread.sleep(5000);

      }

      catch(InterruptedException ie)

      {

        MetaCatUtil.debugMessage("main thread interrupted: " + ie.getMessage(), 30);

      }

      //this is a manual override of jndi's hideously long time

      //out period.

      util.debugMessage("Awake after 5 seconds.", 40);

      if (referralContext == null)

      {

        util.debugMessage("thread timed out...returning groups: " + uvec.toString(), 35);

        String groups[] = new String[uvec.size()];

        for(int i=0; i<uvec.size(); i++)

        {

          groups[i] = (String)uvec.elementAt(i);

        }

        t.interrupt();

        return groups;

      }

      DirContext dc = (DirContext)referralContext;

      String[] attrIDs = {"cn"};

      // Specify the attributes to match.

      // Groups are objects with attribute objectclass=groupofuniquenames.

      // and have attribute uniquemember: uid=foruser,ldapbase.

      SearchControls ctls = new SearchControls();

      ctls.setReturningAttributes(attrIDs);

      ctls.setSearchScope(SearchControls.SUBTREE_SCOPE);

      String filter = null;

      String gfilter = "(objectClass=groupOfUniqueNames)";

      if (null == foruser) {

          filter = gfilter;

      } else {

          filter = "(& " + gfilter + "(uniqueMember=" + foruser + "))";

      }

      try

      {

        NamingEnumeration enum = dc.search(ldapBase, filter, ctls);

        // Print the groups

        while (enum.hasMore()) {

          SearchResult sr = (SearchResult)enum.next();

          uvec.add(sr.getName()+","+ldapBase);

        }

        referralContext.close();

        dc.close();

      }

      catch(NamingException ne)

      {

        MetaCatUtil.debugMessage("Naming Exception in AuthLdap.getGroups", 30);

      }

    } catch (NamingException e) {

      e.printStackTrace(System.err);

      String groups[] = new String[uvec.size()];

      for(int i=0; i<uvec.size(); i++)

      {

        groups[i] = (String)uvec.elementAt(i);

      }

      return groups;

       /*throw new ConnectException(

      "Problem getting groups for a user in AuthLdap.getGroups:" + e);*/

    } 

    MetaCatUtil.debugMessage("The user is in the following groups: " + 

                              uvec.toString(), 35);

    String groups[] = new String[uvec.size()];

    for(int i=0; i<uvec.size(); i++)

    {

      groups[i] = (String)uvec.elementAt(i);

    }

    return groups;

  }

  /**

   * Get attributes describing a user or group

   *

   * @param foruser the user for which the attribute list is requested

   * @returns HashMap a map of attribute name to a Vector of values

   */

  public HashMap getAttributes(String foruser) 

         throws ConnectException

  {

    return getAttributes(null, null, foruser);

  }

  /**

   * Get attributes describing a user or group

   *

   * @param user the user for authenticating against the service

   * @param password the password for authenticating against the service

   * @param foruser the user whose attributes should be returned

   * @returns HashMap a map of attribute name to a Vector of values

   */

  public HashMap getAttributes(String user, String password, String foruser) 

         throws ConnectException

  {

    HashMap attributes = new HashMap();

    String ldapUrl = this.ldapUrl;

    String ldapBase = this.ldapBase;

    String userident = foruser;

    // Identify service provider to use

    Hashtable env = new Hashtable(11);

    env.put(Context.INITIAL_CONTEXT_FACTORY, 

        "com.sun.jndi.ldap.LdapCtxFactory");

    env.put(Context.REFERRAL, referral);

    env.put(Context.PROVIDER_URL, ldapUrl);

    try {

      // Create the initial directory context

      DirContext ctx = new InitialDirContext(env);

      // Ask for all attributes of the user 

      //Attributes attrs = ctx.getAttributes(userident);

      Attributes attrs = ctx.getAttributes(foruser);

      // Print all of the attributes

      NamingEnumeration en = attrs.getAll();

      while (en.hasMore()) {

        Attribute att = (Attribute)en.next();

        Vector values = new Vector();

        String attName = att.getID();

        NamingEnumeration attvalues = att.getAll();

        while (attvalues.hasMore()) {

          String value = (String)attvalues.next();

          values.add(value);

        }

        attributes.put(attName, values);

      }

      // Close the context when we're done

      ctx.close();

    } catch (NamingException e) {

      util.debugMessage("Problem getting attributes in " + 

              "AuthLdap.getAttributes:" + e, 35);

      throw new ConnectException(

      "Problem getting attributes in AuthLdap.getAttributes:" + e);

    }

    return attributes;

  }

  /**

   * Get list of all subtrees holding Metacat's groups and users

   * starting from the Metacat LDAP root, 

   * i.e. ldap://dev.nceas.ucsb.edu/dc=ecoinformatics,dc=org

   */

  private Hashtable getSubtrees(String user, String password,

                                String ldapUrl, String ldapBase)

                throws ConnectException

  {

    Hashtable trees = new Hashtable();

    // Identify service provider to use

    Hashtable env = new Hashtable(11);

    env.put(Context.INITIAL_CONTEXT_FACTORY, 

            "com.sun.jndi.ldap.LdapCtxFactory");

    env.put(Context.REFERRAL, referral);

    env.put(Context.PROVIDER_URL, ldapUrl + ldapBase);

    try {

        // Create the initial directory context

        DirContext ctx = new InitialDirContext(env);

        // Specify the ids of the attributes to return

        String[] attrIDs = {"o","ref"};

        SearchControls ctls = new SearchControls();

        ctls.setReturningAttributes(attrIDs);

        ctls.setSearchScope(SearchControls.SUBTREE_SCOPE);

        // Specify the attributes to match.

        // Subtrees from the main server are found as objects with attribute

        // objectclass=organization or objectclass=referral to the subtree

        // resided on other server.

        String filter = "(|(objectclass=organization)(objectclass=referral))";

        // Search for objects in the current context

        NamingEnumeration enum = ctx.search("", filter, ctls);

        // Print the subtrees' <ldapURL, baseDN>

        while (enum.hasMore()) {

          SearchResult sr = (SearchResult)enum.next();

          Attributes attrs = sr.getAttributes();

          NamingEnumeration enum1 = attrs.getAll(); // "dc" and "ref" attrs

          if (enum1.hasMore()) {

            Attribute attr = (Attribute)enum1.next();

            String attrValue = (String)attr.get();

            String attrName = (String)attr.getID();

            if ( enum1.hasMore() ) {

              attr = (Attribute)enum1.next();

              String refValue = (String)attr.get();

              String refName = (String)attr.getID();

               if ( ldapBase.startsWith(refName + "=" + refValue) ) {

                trees.put(ldapBase,

                         attrValue.substring(0,attrValue.lastIndexOf("/")+1) );

              } else {

                trees.put(refName + "=" + refValue + "," + ldapBase,

                         attrValue.substring(0,attrValue.lastIndexOf("/")+1) );

              }

            } else if ( ldapBase.startsWith(attrName + "=" + attrValue) ) {

                trees.put(ldapBase, ldapUrl);

            } else {              

                trees.put(attrName + "=" + attrValue + "," + ldapBase, ldapUrl);               

            }

          }

        }

        // Close the context when we're done

        ctx.close();

    } catch (NamingException e) {

      util.debugMessage("Problem getting subtrees in AuthLdap.getSubtrees:" 

                        + e, 30);

      throw new ConnectException(

      "Problem getting subtrees in AuthLdap.getSubtrees:" + e);

    }

    return trees;

  }

  /**

   * Get all groups and users from authentication scheme.

   * The output is formatted in XML.

   * @param user the user which requests the information

   * @param password the user's password

   */

  public String getPrincipals(String user, String password)

                throws ConnectException

  {