/*
 * Copyright (c) 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.
 *
 * 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.
 */

/*
 * @test
 * @bug 8182672
 * @summary Java 8u121 on Linux intermittently returns null for MAC address
 *
 */

import java.net.NetworkInterface;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class GetMacAddress implements Runnable {
    String threadName;
    NetworkInterface ni;
    int count;
    static volatile boolean failed = false;
    static final int NUM_THREADS = 5;
    static final int NUM_ITERS = 100;

    public GetMacAddress(NetworkInterface ni, String name) {
        this.ni = ni;
        this.threadName = name;
    }

    public void run() {
        try {
            for (int i = 0; i < NUM_ITERS; i++) {
                byte[] addr = ni.getHardwareAddress();
                if (addr == null) {
                    System.out.println("mac id is null: " + threadName);
                    failed = true;
                }
                count = count + 1;
                if (count % 100 == 0) {
                    System.out.println("Count - " + count +
                            " - " + threadName);
                }
            }
        } catch (Exception ex) {
            System.out.println("Not expecting exception:");
            ex.printStackTrace();
            failed = true;
        }
    }

    public static void main(String[] args) throws Exception {
        ArrayList<NetworkInterface> toTest = new ArrayList<>();
        ExecutorService executor;
        Enumeration<NetworkInterface> e = NetworkInterface.getNetworkInterfaces();

        // first, build a list of interfaces which we can test with
        while (e.hasMoreElements()) {
            NetworkInterface ni = e.nextElement();
            try {
                byte[] addr = ni.getHardwareAddress();
                if (addr == null ) {
                    System.out.println("Not testing null addr: " + ni.getName());
                } else {
                    toTest.add(ni);
                }
            } catch (Exception ex) {
                System.out.println("Not testing: " + ni.getName() +
                    " " + ex.getMessage());
            }
        }
        for (NetworkInterface ni : toTest) {
            executor = Executors.newFixedThreadPool(NUM_THREADS);
            System.out.println("Testing: " + ni.getName());
            for (int i = 0; i < NUM_THREADS; i++) {
                Runnable testworker =
                        new GetMacAddress(ni, ni.getName() +"-Thread-" + i);
                executor.execute(testworker);
            }
            executor.shutdown();
            while (!executor.isTerminated()) {
            }
        }
        if (!failed) {
            System.out.println("Finished all threads");
        } else {
            throw new RuntimeException("Failed");
        }
    }
}