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

[Langer, Christoph]

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");
>          }
>      }
> }