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

[Seán Coffey]

Thanks all. There were a few shouts from Chris in the office when he saw 
my Enumeration code ;)

I'm running this through our test system again and will push if I get 
green results.

Regards,
Sean.

On 23/06/17 14:40, Langer, Christoph wrote:
> Hi,
>
> looks like a great piece of modern concurrent Java coding :) Well done! +1
>
> Best regards
> Christoph
>
>> -----Original Message-----
>> From: Chris Hegarty [mailto:chris.hegarty at oracle.com]
>> Sent: Freitag, 23. Juni 2017 15:28
>> To: Seán Coffey <sean.coffey at oracle.com>; Langer, Christoph
>> <christoph.langer at sap.com>
>> Cc: net-dev <net-dev at openjdk.java.net>
>> Subject: Re: RFR : 8182672: Java 8u121 on Linux intermittently returns null for
>> MAC address
>>
>>
>>
>> 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");
>>           }
>>       }
>> }