1 /*
 2  * Copyright (c) 2020, 2021, 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
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24  */
25 package sun.nio.ch;
26 
27 import java.io.IOException;
28 import static sun.nio.ch.WEPoll.*;
29 
30 /**
31  * Poller implementation based on wepoll.
32  */
33 class WEPollPoller extends Poller {
34     private static final int MAX_EVENTS_TO_POLL = 256;
35     private static final int ENOENT = 2;
36 
37     private final long handle;
38     private final int event;
39     private final long address;
40 
41     WEPollPoller(boolean read) throws IOException {
42         this.handle = WEPoll.create();
43         this.event = (read) ? EPOLLIN : EPOLLOUT;
44         this.address = WEPoll.allocatePollArray(MAX_EVENTS_TO_POLL);
45     }
46 
47     @Override
48     void implRegister(int fdVal) throws IOException {
49         // re-arm
50         int err = WEPoll.ctl(handle, EPOLL_CTL_MOD, fdVal, (event | EPOLLONESHOT));
51         if (err == ENOENT)
52             err = WEPoll.ctl(handle, EPOLL_CTL_ADD, fdVal, (event | EPOLLONESHOT));
53         if (err != 0)
54             throw new IOException("epoll_ctl failed: " + err);
55     }
56 
57     @Override
58     void implDeregister(int fdVal) {
59         WEPoll.ctl(handle, EPOLL_CTL_DEL, fdVal, 0);
60     }
61 
62     @Override
63     int poll(int timeout) throws IOException {
64         int n = WEPoll.wait(handle, address, MAX_EVENTS_TO_POLL, timeout);
65         int i = 0;
66         while (i < n) {
67             long event = WEPoll.getEvent(address, i);
68             int fdVal = WEPoll.getDescriptor(event);
69             polled(fdVal);
70             i++;
71         }
72         return n;
73     }
74 }
75