/*
 * Portions Copyright 2000-2009 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

/*
 *  (C) Copyright IBM Corp. 1999 All Rights Reserved.
 *  Copyright 1997 The Open Group Research Institute.  All rights reserved.
 */

package sun.security.krb5.internal.tools;

import sun.security.krb5.*;
import sun.security.krb5.internal.*;
import sun.security.krb5.internal.ccache.*;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.util.StringTokenizer;
import java.io.File;
import java.util.Arrays;
import sun.security.util.Password;

/**
 * Kinit tool for obtaining Kerberos v5 tickets.
 *
 * @author Yanni Zhang
 * @author Ram Marti
 */
public class Kinit {

    private KinitOptions options;
    private static final boolean DEBUG = Krb5.DEBUG;

    /**
     * The main method is used to accept user command line input for ticket
     * request.
     * <p>
     * Usage: kinit [-A] [-f] [-p] [-c cachename] [[-k [-t keytab_file_name]]
     * [principal] [password]
     * <ul>
     * <li>    -A        do not include addresses
     * <li>    -f        forwardable
     * <li>    -p        proxiable
     * <li>    -c        cache name (i.e., FILE://c:\temp\mykrb5cc)
     * <li>    -k        use keytab
     * <li>    -t        keytab file name
     * <li>    principal the principal name (i.e., duke@java.sun.com)
     * <li>    password  the principal's Kerberos password
     * </ul>
     * <p>
     * Use java sun.security.krb5.tools.Kinit -help to bring up help menu.
     * <p>
     * We currently support only file-based credentials cache to
     * store the tickets obtained from the KDC.
     * By default, for all Unix platforms a cache file named
     * /tmp/krb5cc_&lt;uid&gt will be generated. The &lt;uid&gt is the
     * numeric user identifier.
     * For all other platforms, a cache file named
     * &lt;USER_HOME&gt/krb5cc_&lt;USER_NAME&gt would be generated.
     * <p>
     * &lt;USER_HOME&gt is obtained from <code>java.lang.System</code>
     * property <i>user.home</i>.
     * &lt;USER_NAME&gt is obtained from <code>java.lang.System</code>
     * property <i>user.name</i>.
     * If &lt;USER_HOME&gt is null the cache file would be stored in
     * the current directory that the program is running from.
     * &lt;USER_NAME&gt is operating system's login username.
     * It could be different from user's principal name.
     *</p>
     *<p>
     * For instance, on Windows NT, it could be
     * c:\winnt\profiles\duke\krb5cc_duke, in
     * which duke is the &lt;USER_NAME&gt, and c:\winnt\profile\duke is the
     * &lt;USER_HOME&gt.
     *<p>
     * A single user could have multiple principal names,
     * but the primary principal of the credentials cache could only be one,
     * which means one cache file could only store tickets for one
     * specific user principal. If the user switches
     * the principal name at the next Kinit, the cache file generated for the
     * new ticket would overwrite the old cache file by default.
     * To avoid overwriting, you need to specify
     * a different cache file name when you request a
     * new ticket.
     *</p>
     *<p>
     * You can specify the location of the cache file by using the -c option
     *
     */

    public static void main(String[] args) {
        try {
            Kinit self = new Kinit(args);
        }
        catch (Exception e) {
            String msg = null;
            if (e instanceof KrbException) {
                msg = ((KrbException)e).krbErrorMessage() + " " +
                    ((KrbException)e).returnCodeMessage();
            } else  {
                msg = e.getMessage();
            }
            if (msg != null) {
                System.err.println("Exception: " + msg);
            } else {
                System.out.println("Exception: " + e);
            }
            e.printStackTrace();
            System.exit(-1);
        }
        return;
    }

    /**
     * Constructs a new Kinit object.
     * @param args array of ticket request options.
     * Avaiable options are: -f, -p, -c, principal, password.
     * @exception IOException if an I/O error occurs.
     * @exception RealmException if the Realm could not be instantiated.
     * @exception KrbException if error occurs during Kerberos operation.
     */
    private Kinit(String[] args)
        throws IOException, RealmException, KrbException {
        if (args == null || args.length == 0) {
            options = new KinitOptions();
        } else {
            options = new KinitOptions(args);
        }
        String princName = null;
        PrincipalName principal = options.getPrincipal();
        if (principal != null) {
            princName = principal.toString();
        }
        if (DEBUG) {
            System.out.println("Principal is " + principal);
        }
        char[] psswd = options.password;
        EncryptionKey[] skeys = null;
        boolean useKeytab = options.useKeytabFile();
        if (!useKeytab) {
            if (princName == null) {
                throw new IllegalArgumentException
                    (" Can not obtain principal name");
            }
            if (psswd == null) {
                System.out.print("Password for " + princName + ":");
                System.out.flush();
                psswd = Password.readPassword(System.in);
                if (DEBUG) {
                    System.out.println(">>> Kinit console input " +
                        new String(psswd));
                }
            }
        } else {
            if (DEBUG) {
                System.out.println(">>> Kinit using keytab");
            }
            if (princName == null) {
                throw new IllegalArgumentException
                    ("Principal name must be specified.");
            }
            String ktabName = options.keytabFileName();
            if (ktabName != null) {
                if (DEBUG) {
                    System.out.println(
                                       ">>> Kinit keytab file name: " + ktabName);
                }
            }

            // assert princName and principal are nonnull
            skeys = EncryptionKey.acquireSecretKeys(principal, ktabName);

            if (skeys == null || skeys.length == 0) {
                String msg = "No supported key found in keytab";
                if (princName != null) {
                    msg += " for principal " + princName;
                }
                throw new KrbException(msg);
            }
        }

        KDCOptions opt = new KDCOptions();
        setOptions(KDCOptions.FORWARDABLE, options.forwardable, opt);
        setOptions(KDCOptions.PROXIABLE, options.proxiable, opt);
        String realm = options.getKDCRealm();
        if (realm == null) {
            realm = Config.getInstance().getDefaultRealm();
        }

        if (DEBUG) {
            System.out.println(">>> Kinit realm name is " + realm);
        }

        PrincipalName sname = new PrincipalName("krbtgt" + "/" + realm,
                                        PrincipalName.KRB_NT_SRV_INST);
        sname.setRealm(realm);

        if (DEBUG) {
            System.out.println(">>> Creating KrbAsReq");
        }

        KrbAsReq as_req = null;
        HostAddresses addresses = null;
        try {
            if (options.getAddressOption())
                addresses = HostAddresses.getLocalAddresses();

            if (useKeytab) {
                as_req = new KrbAsReq(skeys, opt,
                                      principal, sname,
                                      null, null, null, null, addresses, null);
            } else {
                as_req = new KrbAsReq(psswd, opt,
                                      principal, sname,
                                      null, null, null, null, addresses, null);
            }
        } catch (KrbException exc) {
            throw exc;
        } catch (Exception exc) {
            throw new KrbException(exc.toString());
        }

        KrbAsRep as_rep = null;
        try {
            as_rep = sendASRequest(as_req, useKeytab, realm, psswd, skeys);
        } catch (KrbException ke) {
            if ((ke.returnCode() == Krb5.KDC_ERR_PREAUTH_FAILED) ||
                (ke.returnCode() == Krb5.KDC_ERR_PREAUTH_REQUIRED)) {
                if (DEBUG) {
                    System.out.println("Kinit: PREAUTH FAILED/REQ, re-send AS-REQ");
                }
                KRBError error = ke.getError();
                int etype = error.getEType();
                String salt = error.getSalt();
                byte[] s2kparams = error.getParams();
                if (useKeytab) {
                    as_req = new KrbAsReq(skeys, true, etype, salt,
                                        s2kparams, opt, principal, sname,
                                        null, null, null, null, addresses, null);
                } else {
                    as_req = new KrbAsReq(psswd, true, etype, salt,
                                        s2kparams, opt, principal, sname,
                                        null, null, null, null, addresses, null);
                }
                as_rep = sendASRequest(as_req, useKeytab, realm, psswd, skeys);
            } else {
                throw ke;
            }
        }

        sun.security.krb5.internal.ccache.Credentials credentials =
            as_rep.setCredentials();
        // we always create a new cache and store the ticket we get
        CredentialsCache cache =
            CredentialsCache.create(principal, options.cachename);
        if (cache == null) {
           throw new IOException("Unable to create the cache file " +
                                 options.cachename);
        }
        cache.update(credentials);
        cache.save();

        if (options.password == null) {
            // Assume we're running interactively
            System.out.println("New ticket is stored in cache file " +
                               options.cachename);
         } else {
             Arrays.fill(options.password, '0');
         }

        // clear the password
        if (psswd != null) {
            Arrays.fill(psswd, '0');
        }
        options = null; // release reference to options
    }

    private static KrbAsRep sendASRequest(KrbAsReq as_req, boolean useKeytab,
                String realm, char[] passwd, EncryptionKey[] skeys)
        throws IOException, RealmException, KrbException {

        if (DEBUG) {
            System.out.println(">>> Kinit: sending as_req to realm " + realm);
        }

        String kdc = as_req.send(realm);

        if (DEBUG) {
            System.out.println(">>> reading response from kdc");
        }
        KrbAsRep as_rep = null;
        try {
            if (useKeytab) {
                as_rep = as_req.getReply(skeys);
            } else {
                as_rep = as_req.getReply(passwd);
            }
        } catch (KrbException ke) {
            if (ke.returnCode() == Krb5.KRB_ERR_RESPONSE_TOO_BIG) {
                as_req.send(realm, kdc, true); // useTCP is set
                if (useKeytab) {
                    as_rep = as_req.getReply(skeys);
                } else {
                    as_rep = as_req.getReply(passwd);
                }
            } else {
                throw ke;
            }
        }
        return as_rep;
    }

    private static void setOptions(int flag, int option, KDCOptions opt) {
        switch (option) {
        case 0:
            break;
        case -1:
            opt.set(flag, false);
            break;
        case 1:
            opt.set(flag, true);
        }
    }
}