1 /*
2 * Copyright (c) 2005, 2010, 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
26 package sun.nio.ch;
27
28 import java.io.IOException;
29 import java.nio.channels.*;
30 import java.nio.channels.spi.*;
31 import java.util.*;
32 import sun.misc.*;
33
34 /**
35 * An implementation of Selector for Linux 2.6+ kernels that uses
36 * the epoll event notification facility.
37 */
38 class EPollSelectorImpl
39 extends SelectorImpl
40 {
41
42 // File descriptors used for interrupt
43 protected int fd0;
44 protected int fd1;
45
46 // The poll object
47 EPollArrayWrapper pollWrapper;
48
49 // Maps from file descriptors to keys
50 private Map<Integer,SelectionKeyImpl> fdToKey;
51
52 // True if this Selector has been closed
53 private volatile boolean closed = false;
54
55 // Lock for interrupt triggering and clearing
56 private Object interruptLock = new Object();
57 private boolean interruptTriggered = false;
58
59 /**
60 * Package private constructor called by factory method in
61 * the abstract superclass Selector.
62 */
63 EPollSelectorImpl(SelectorProvider sp) {
64 super(sp);
65 long pipeFds = IOUtil.makePipe(false);
66 fd0 = (int) (pipeFds >>> 32);
67 fd1 = (int) pipeFds;
68 pollWrapper = new EPollArrayWrapper();
69 pollWrapper.initInterrupt(fd0, fd1);
70 fdToKey = new HashMap<Integer,SelectionKeyImpl>();
71 }
72
73 protected int doSelect(long timeout)
74 throws IOException
75 {
76 if (closed)
77 throw new ClosedSelectorException();
78 processDeregisterQueue();
79 try {
80 begin();
81 pollWrapper.poll(timeout);
82 } finally {
83 end();
84 }
85 processDeregisterQueue();
86 int numKeysUpdated = updateSelectedKeys();
87 if (pollWrapper.interrupted()) {
88 // Clear the wakeup pipe
89 pollWrapper.putEventOps(pollWrapper.interruptedIndex(), 0);
90 synchronized (interruptLock) {
91 pollWrapper.clearInterrupted();
92 IOUtil.drain(fd0);
93 interruptTriggered = false;
94 }
95 }
96 return numKeysUpdated;
97 }
98
99 /**
100 * Update the keys whose fd's have been selected by the epoll.
101 * Add the ready keys to the ready queue.
102 */
103 private int updateSelectedKeys() {
104 int entries = pollWrapper.updated;
105 int numKeysUpdated = 0;
106 for (int i=0; i<entries; i++) {
107 int nextFD = pollWrapper.getDescriptor(i);
108 SelectionKeyImpl ski = fdToKey.get(Integer.valueOf(nextFD));
109 // ski is null in the case of an interrupt
110 if (ski != null) {
111 int rOps = pollWrapper.getEventOps(i);
112 if (selectedKeys.contains(ski)) {
113 if (ski.channel.translateAndSetReadyOps(rOps, ski)) {
114 numKeysUpdated++;
115 }
116 } else {
117 ski.channel.translateAndSetReadyOps(rOps, ski);
118 if ((ski.nioReadyOps() & ski.nioInterestOps()) != 0) {
119 selectedKeys.add(ski);
120 numKeysUpdated++;
121 }
122 }
123 }
124 }
125 return numKeysUpdated;
126 }
127
128 protected void implClose() throws IOException {
129 if (closed)
130 return;
131 closed = true;
132
133 // prevent further wakeup
134 synchronized (interruptLock) {
135 interruptTriggered = true;
136 }
137
138 FileDispatcherImpl.closeIntFD(fd0);
139 FileDispatcherImpl.closeIntFD(fd1);
140
141 pollWrapper.closeEPollFD();
142 // it is possible
143 selectedKeys = null;
144
145 // Deregister channels
146 Iterator<SelectionKey> i = keys.iterator();
147 while (i.hasNext()) {
148 SelectionKeyImpl ski = (SelectionKeyImpl)i.next();
149 deregister(ski);
150 SelectableChannel selch = ski.channel();
151 if (!selch.isOpen() && !selch.isRegistered())
152 ((SelChImpl)selch).kill();
153 i.remove();
154 }
155
156 fd0 = -1;
157 fd1 = -1;
158 }
159
160 protected void implRegister(SelectionKeyImpl ski) {
161 if (closed)
162 throw new ClosedSelectorException();
163 SelChImpl ch = ski.channel;
164 fdToKey.put(Integer.valueOf(ch.getFDVal()), ski);
165 pollWrapper.add(ch);
166 keys.add(ski);
167 }
168
169 protected void implDereg(SelectionKeyImpl ski) throws IOException {
170 assert (ski.getIndex() >= 0);
171 SelChImpl ch = ski.channel;
172 int fd = ch.getFDVal();
173 fdToKey.remove(Integer.valueOf(fd));
174 pollWrapper.release(ch);
175 ski.setIndex(-1);
176 keys.remove(ski);
177 selectedKeys.remove(ski);
178 deregister((AbstractSelectionKey)ski);
179 SelectableChannel selch = ski.channel();
180 if (!selch.isOpen() && !selch.isRegistered())
181 ((SelChImpl)selch).kill();
182 }
183
184 void putEventOps(SelectionKeyImpl sk, int ops) {
185 if (closed)
186 throw new ClosedSelectorException();
187 pollWrapper.setInterest(sk.channel, ops);
188 }
189
190 public Selector wakeup() {
191 synchronized (interruptLock) {
192 if (!interruptTriggered) {
193 pollWrapper.interrupt();
194 interruptTriggered = true;
195 }
196 }
197 return this;
198 }
199
200 static {
201 Util.load();
202 }
203
204 }