1 /*
2 * Copyright (c) 2017, 2023, 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 import java.io.UncheckedIOException;
29 import java.lang.ref.Cleaner.Cleanable;
30 import jdk.internal.ref.CleanerFactory;
31 import static sun.nio.ch.EPoll.*;
32
33 /**
34 * Poller implementation based on the epoll facility.
35 */
36
37 class EPollPoller extends Poller {
38 private static final int ENOENT = 2;
39
40 private final int epfd;
41 private final int event;
42 private final int maxEvents;
43 private final long address;
44 private final Cleanable cleaner;
45
46 EPollPoller(boolean subPoller, boolean read) throws IOException {
47 this.epfd = EPoll.create();
48 this.event = (read) ? EPOLLIN : EPOLLOUT;
49 this.maxEvents = (subPoller) ? 64 : 512;
50 this.address = EPoll.allocatePollArray(maxEvents);
51 if (subPoller) {
52 this.cleaner = CleanerFactory.cleaner().register(this, release(epfd, address));
53 } else {
54 this.cleaner = null;
55 }
56 }
57
58 @Override
59 void close() {
60 cleaner.clean();
61 }
62
63 /**
64 * Closes epoll instance and release poll array.
65 */
66 private static Runnable release(int epfd, long address) {
67 return () -> {
68 try {
69 FileDispatcherImpl.closeIntFD(epfd);
70 } catch (IOException ioe) {
71 throw new UncheckedIOException(ioe);
72 } finally {
73 // release memory
74 EPoll.freePollArray(address);
75 }
76 };
77 }
78
79 @Override
80 int fdVal() {
81 return epfd;
82 }
83
84 @Override
85 void implRegister(int fdVal) throws IOException {
86 // re-arm
87 int err = EPoll.ctl(epfd, EPOLL_CTL_MOD, fdVal, (event | EPOLLONESHOT));
88 if (err == ENOENT)
89 err = EPoll.ctl(epfd, EPOLL_CTL_ADD, fdVal, (event | EPOLLONESHOT));
90 if (err != 0)
91 throw new IOException("epoll_ctl failed: " + err);
92 }
93
94 @Override
95 void implDeregister(int fdVal, boolean polled) {
96 // event is disabled if already polled
97 if (!polled) {
98 EPoll.ctl(epfd, EPOLL_CTL_DEL, fdVal, 0);
99 }
100 }
101
102 @Override
103 int poll(int timeout) throws IOException {
104 int n = EPoll.wait(epfd, address, maxEvents, timeout);
105 int i = 0;
106 while (i < n) {
107 long eventAddress = EPoll.getEvent(address, i);
108 int fdVal = EPoll.getDescriptor(eventAddress);
109 polled(fdVal);
110 i++;
111 }
112 return n;
113 }
114 }
115