RFR : 8182672: Java 8u121 on Linux intermittently returns null for MAC address

[Vyom Tewari]

Hi Chris,

test looks good, one minor comment can be ignored, in failing case it 
print stack and "Exception in thread "main" java.lang.RuntimeException: 
Failed" both. I can see main is declared to throw Exception. Is is 
possible to throw exception instead of  printing trace or pass this 
exception to last line ?

Thanks,

Vyom


On Friday 23 June 2017 06:58 PM, Chris Hegarty wrote:
>
>
> On 23/06/17 10:56, Seán Coffey wrote:
>> Thanks to Christoph, Vyom and Mark for the reviews.
>>
>> I've improved the testcase as per feedback. Hope this meets all 
>> requests :
>>
>> http://cr.openjdk.java.net/~coffeys/webrev.8182672.jdk10.v2/webrev/
>
> The change looks good.
>
> Sean and I did a live coding session and arrived at the following
> version of the test.
>
> -Chris.
>
> /*
>  * 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.List;
> import java.util.concurrent.Callable;
> import java.util.concurrent.ExecutorService;
> import java.util.concurrent.Executors;
> import java.util.concurrent.Future;
> import java.util.concurrent.Phaser;
> import java.util.function.Predicate;
> import java.util.stream.Collectors;
>
> public class GetMacAddress implements Callable<Exception> {
>     static final int NUM_THREADS = 5;
>     static final int NUM_ITERS = 100;
>     static volatile boolean failed; // false
>
>     final String threadName;
>     final NetworkInterface ni;
>     final Phaser startingGate;
>
>     public GetMacAddress(NetworkInterface ni, String name, Phaser 
> phaser) {
>         this.ni = ni;
>         this.threadName = name;
>         this.startingGate = phaser;
>     }
>
>     @Override
>     public Exception call() {
>         int count = 0;
>         startingGate.arriveAndAwaitAdvance();
>         try {
>             for (int i = 0; i < NUM_ITERS; i++) {
>                 ni.getMTU();
>                 byte[] addr = ni.getHardwareAddress();
>                 if (addr == null) {
>                     System.out.println(threadName + ". mac id is null");
>                     failed = true;
>                 }
>                 count = count + 1;
>                 if (count % 100 == 0) {
>                     System.out.println(threadName + ". count is " + 
> count);
>                 }
>             }
>         } catch (Exception ex) {
>             System.out.println(threadName + ". Not expecting 
> exception:" + ex.getMessage());
>             failed = true;
>             return ex;
>         }
>         return null;
>     }
>
>     static final Predicate<NetworkInterface> hasHardwareAddress = ni -> {
>         try {
>             if (ni.getHardwareAddress() == null) {
>                 System.out.println("Not testing null addr: " + 
> ni.getName());
>                 return false;
>             }
>         } catch (Exception ex) {
>             System.out.println("Not testing: " + ni.getName() +
>                     " " + ex.getMessage());
>         }
>         return true;
>     };
>
>     public static void main(String[] args) throws Exception {
>         List<NetworkInterface> toTest = 
> NetworkInterface.networkInterfaces()
>                         .filter(hasHardwareAddress)
>                         .collect(Collectors.toList());
>
>         ExecutorService executor = 
> Executors.newFixedThreadPool(NUM_THREADS);
>
>         for (NetworkInterface ni : toTest) {
>             Phaser startingGate = new Phaser(NUM_THREADS);
>             System.out.println("Testing: " + ni.getName());
>             List<Callable<Exception>> list = new ArrayList<>();
>             for (int i = 0; i < NUM_THREADS; i++)
>                 list.add(new GetMacAddress(ni, ni.getName() + 
> "-Thread-" + i, startingGate));
>             List<Future<Exception>> futures = executor.invokeAll(list);
>             for (Future<Exception> f : futures) {
>                 if (f.get() != null)
>                     f.get().printStackTrace(System.out);
>             }
>             if (failed)
>                 break;
>         }
>         executor.shutdownNow();
>         if (!failed) {
>             System.out.println("PASSED - Finished all threads");
>         } else {
>             throw new RuntimeException("Failed");
>         }
>     }
> }