1 /*
   2  * Copyright (c) 2017, Oracle and/or its affiliates. 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.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package sun.nio.ch;
  26 
  27 import java.io.IOException;
  28 
  29 import static sun.nio.ch.EPoll.EPOLL_CTL_ADD;
  30 import static sun.nio.ch.EPoll.EPOLL_CTL_DEL;
  31 import static sun.nio.ch.EPoll.EPOLL_CTL_MOD;
  32 import static sun.nio.ch.EPoll.EPOLLONESHOT;
  33 
  34 /**
  35  * Poller implementation based on the epoll facility.
  36  */
  37 
  38 class EPollPoller extends Poller {
  39     private static final int MAX_EVENTS_TO_POLL = 512;
  40     private static final int ENOENT = 2;
  41 
  42     private final int epfd;
  43     private final int event;
  44     private final long address;
  45 
  46     EPollPoller(int event) throws IOException {
  47         this.epfd = EPoll.create();
  48         this.event = event;
  49         this.address = EPoll.allocatePollArray(MAX_EVENTS_TO_POLL);
  50     }
  51 
  52     @Override
  53     protected void implRegister(int fdVal) {
  54         // re-arm
  55         int err = EPoll.ctl(epfd, EPOLL_CTL_MOD, fdVal, (event | EPOLLONESHOT));
  56         if (err == ENOENT)
  57             err = EPoll.ctl(epfd, EPOLL_CTL_ADD, fdVal, (event | EPOLLONESHOT));
  58         if (err != 0)
  59             throw new InternalError("epoll_ctl failed: " + err);
  60     }
  61 
  62     @Override
  63     protected boolean implDeregister(int fdVal) {
  64         int err = EPoll.ctl(epfd, EPOLL_CTL_DEL, fdVal, 0);
  65         return (err == 0);
  66     }
  67 
  68     @Override
  69     public void run() {
  70         try {
  71             for (;;) {
  72                 int n = EPoll.wait(epfd, address, MAX_EVENTS_TO_POLL, -1);
  73                 while (n-- > 0) {
  74                     long eventAddress = EPoll.getEvent(address, n);
  75                     int fdVal = EPoll.getDescriptor(eventAddress);
  76                     polled(fdVal);
  77                 }
  78             }
  79         } catch (Throwable t) {
  80             t.printStackTrace();
  81         }
  82     }
  83 }
  84