1 /*

     2  * Copyright 2009 Sun Microsystems, Inc.  All Rights Reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  */

    23 

    24 /* @test

    25  * @bug 6693490

    26  * @summary Pre-close file descriptor may inadvertently get registered with

    27  *     epoll during close

    28  */

    29 

    30 import java.net.*;

    31 import java.nio.channels.*;

    32 import java.util.concurrent.*;

    33 import java.util.*;

    34 import java.io.IOException;

    35 

    36 public class RegAfterPreClose {

    37 

    38     static volatile boolean done;

    39 

    40     /**

    41      * A task that continuously connects to a given address and immediately

    42      * closes the connection.

    43      */

    44     static class Connector implements Runnable {

    45         private final SocketAddress sa;

    46         Connector(int port) throws IOException {

    47             InetAddress lh = InetAddress.getLocalHost();

    48             this.sa = new InetSocketAddress(lh, port);

    49         }

    50         public void run() {

    51             while (!done) {

    52                 try {

    53                     SocketChannel.open(sa).close();

    54                 } catch (IOException x) {

    55                     // back-off as probably resource related

    56                     try {

    57                         Thread.sleep(10);

    58                     } catch (InterruptedException  ignore) { }

    59                 }

    60             }

    61         }

    62     }

    63 

    64     /**

    65      * A task that closes a channel.

    66      */

    67     static class Closer implements Runnable {

    68         private final Channel channel;

    69         Closer(Channel sc) {

    70             this.channel = sc;

    71         }

    72         public void run() {

    73             try {

    74                 channel.close();

    75             } catch (IOException ignore) { }

    76         }

    77     }

    78 

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

    80         // create listener

    81         InetSocketAddress isa = new InetSocketAddress(0);

    82         ServerSocketChannel ssc = ServerSocketChannel.open();

    83         ssc.socket().bind(isa);

    84 

    85         // register with Selector

    86         final Selector sel = Selector.open();

    87         ssc.configureBlocking(false);

    88         SelectionKey key = ssc.register(sel, SelectionKey.OP_ACCEPT);

    89 

    90         ThreadFactory factory = new ThreadFactory() {

    91             @Override

    92             public Thread newThread(Runnable r) {

    93                 Thread t = new Thread(r);

    94                 t.setDaemon(true);

    95                 return t;

    96             }

    97         };

    98 

    99         // schedule test to run for 1 minute

   100         Executors.newScheduledThreadPool(1, factory).schedule(new Runnable() {

   101             public void run() {

   102                 done = true;

   103                 sel.wakeup();

   104             }}, 1, TimeUnit.MINUTES);

   105 

   106         // create Executor that handles tasks that closes channels

   107         // "asynchronously" - this creates the conditions to provoke the bug.

   108         Executor executor = Executors.newFixedThreadPool(2, factory);

   109 

   110         // submit task that connects to listener

   111         executor.execute(new Connector(ssc.socket().getLocalPort()));

   112 

   113         // loop accepting connections until done (or an IOException is thrown)

   114         while (!done) {

   115             sel.select();

   116             if (key.isAcceptable()) {

   117                 SocketChannel sc = ssc.accept();

   118                 if (sc != null) {

   119                     sc.configureBlocking(false);

   120                     sc.register(sel, SelectionKey.OP_READ);

   121                     executor.execute(new Closer(sc));

   122                 }

   123             }

   124             sel.selectedKeys().clear();

   125         }

   126     }

   127 }