/*

 * Copyright (c) 2005, 2017, Oracle and/or its affiliates. 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package sun.net.www.protocol.http.spnego;

import java.io.IOException;

import java.net.Authenticator;

import java.net.PasswordAuthentication;

import java.util.Arrays;

import javax.security.auth.callback.Callback;

import javax.security.auth.callback.CallbackHandler;

import javax.security.auth.callback.NameCallback;

import javax.security.auth.callback.PasswordCallback;

import javax.security.auth.callback.UnsupportedCallbackException;

import sun.net.www.protocol.http.HttpCallerInfo;

import sun.security.jgss.LoginConfigImpl;

/**

 * @since 1.6

 * Special callback handler used in JGSS for the HttpCaller.

 */

public class NegotiateCallbackHandler implements CallbackHandler {

    private String username;

    private char[] password;

    /**

     * Authenticator asks for username and password in a single prompt,

     * but CallbackHandler checks one by one. So, no matter which callback

     * gets handled first, make sure Authenticator is only called once.

     */

    private boolean answered;

    private final HttpCallerInfo hci;

    public NegotiateCallbackHandler(HttpCallerInfo hci) {

        this.hci = hci;

    }

    private void getAnswer() {

        if (!answered) {

            answered = true;

            if (LoginConfigImpl.HTTP_USE_GLOBAL_CREDS) {

                PasswordAuthentication passAuth =

                        Authenticator.requestPasswordAuthentication(

                                hci.host, hci.addr, hci.port, hci.protocol,

                                hci.prompt, hci.scheme, hci.url, hci.authType);

                /**

                 * To be compatible with existing callback handler implementations,

                 * when the underlying Authenticator is canceled, username and

                 * password are assigned null. No exception is thrown.

                 */

                if (passAuth != null) {

                    username = passAuth.getUserName();

                    password = passAuth.getPassword();

                }

            }

        }

    }

    public void handle(Callback[] callbacks) throws

            UnsupportedCallbackException, IOException {

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

            Callback callBack = callbacks[i];

            if (callBack instanceof NameCallback) {

                getAnswer();

                ((NameCallback)callBack).setName(username);

            } else if (callBack instanceof PasswordCallback) {

                getAnswer();

                ((PasswordCallback)callBack).setPassword(password);

                if (password != null) Arrays.fill(password, ' ');

            } else {

                throw new UnsupportedCallbackException(callBack,

                        "Call back not supported");

            }

        }

    }

}