Java example source code file (KtabZero.java)

This example Java source code file (KtabZero.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

classnotfoundexception, exception, field, keytab, ktabzero, name, object, reflection, string

The KtabZero.java Java example source code

/*
 * Copyright (c) 2013, 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.
 *
 * 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import sun.security.krb5.internal.ktab.KeyTab;
import sun.security.krb5.internal.ktab.KeyTabConstants;

import java.io.File;
import java.lang.reflect.Field;
import java.nio.file.Files;
import java.nio.file.Paths;

/*
 * @test
 * @bug 8014196
 * @summary ktab creates a file with zero kt_vno
 */
public class KtabZero {

    static final String NAME = "k.tab";

    public static void main(String[] args) throws Exception {

        // 0. Non-existing keytab
        Files.deleteIfExists(Paths.get(NAME));
        check(true);

        // 1. Create with KeyTab
        Files.deleteIfExists(Paths.get(NAME));
        KeyTab.getInstance(NAME).save();
        check(false);

        // 2. Create with the tool
        Files.deleteIfExists(Paths.get(NAME));
        try {
            Class ktab = Class.forName("sun.security.krb5.internal.tools.Ktab");
            ktab.getDeclaredMethod("main", String[].class).invoke(null,
                    (Object)(("-k " + NAME + " -a me@HERE pass").split(" ")));
        } catch (ClassNotFoundException cnfe) {
            // Only Windows has ktab tool
            System.out.println("No ktab tool here. Ignored.");
            return;
        }
        check(false);
    }

    // Checks existence as well as kt-vno
    static void check(boolean showBeMissing) throws Exception {
        KeyTab kt = KeyTab.getInstance(NAME);
        if (kt.isMissing() != showBeMissing) {
            throw new Exception("isMissing is not " + showBeMissing);
        }
        Field f = KeyTab.class.getDeclaredField("kt_vno");
        f.setAccessible(true);
        if (f.getInt(kt) != KeyTabConstants.KRB5_KT_VNO) {
            throw new Exception("kt_vno is " + f.getInt(kt));
        }
    }
}