1 /*
2 * Copyright (c) 2020, 2022, 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 jdk.internal.misc.Unsafe;
29
30 /**
31 * Provides access to WSAPoll.
32 */
33 class WSAPoll {
34 private static final Unsafe UNSAFE = Unsafe.getUnsafe();
35 private static final int ADDRESS_SIZE = UNSAFE.addressSize();
36
37 private WSAPoll() { }
38
39 /**
40 * typedef struct pollfd {
41 * SOCKET fd;
42 * SHORT events;
43 * SHORT revents;
44 * } WSAPOLLFD;
45 */
46 static {
47 IOUtil.load();
48 }
49 private static final int SIZE_POLLFD = pollfdSize();
50 private static final int FD_OFFSET = fdOffset();
51 private static final int EVENTS_OFFSET = eventsOffset();
52 private static final int REVENTS_OFFSET = reventsOffset();
53
54 /**
55 * Allocates a poll array of {@code size} WSAPOLLFD structures.
56 */
57 static long allocatePollArray(int size) {
58 if (size <= 0)
59 throw new IllegalArgumentException();
60 return UNSAFE.allocateMemory(size * SIZE_POLLFD);
61 }
62
63 /**
64 * Reallocates a poll array from {@code size} to {@code newSize}
65 * WSAPOLLFD structures.
66 */
67 static long reallocatePollArray(long address, int size, int newSize) {
68 if (newSize < size)
69 throw new IllegalArgumentException();
70 long newAddress = allocatePollArray(newSize);
71 UNSAFE.copyMemory(address, newAddress, size * SIZE_POLLFD);
72 UNSAFE.freeMemory(address);
73 return newAddress;
74 }
75
76 /**
77 * Free a poll array.
78 */
79 static void freePollArray(long address) {
80 UNSAFE.freeMemory(address);
81 }
82
83 static void putDescriptor(long address, int i, int fd) {
84 int offset = SIZE_POLLFD * i + FD_OFFSET;
85 if (ADDRESS_SIZE == 8) {
86 UNSAFE.putLong(address + offset, fd);
87 } else {
88 UNSAFE.putInt(address + offset, fd);
89 }
90 }
91
92 static int getDescriptor(long address, int i) {
93 int offset = SIZE_POLLFD * i + FD_OFFSET;
94 long s;
95 if (ADDRESS_SIZE == 8) {
96 s = UNSAFE.getLong(address + offset);
97 } else {
98 s = UNSAFE.getInt(address + offset);
99 }
100 int fd = (int) s;
101 assert ((long) fd) == s;
102 return fd;
103 }
104
105 static void putEvents(long address, int i, short events) {
106 int offset = SIZE_POLLFD * i + EVENTS_OFFSET;
107 UNSAFE.putShort(address + offset, events);
108 }
109
110 static short getEvents(long address, int i) {
111 int offset = SIZE_POLLFD * i + EVENTS_OFFSET;
112 return UNSAFE.getShort(address + offset);
113 }
114
115 static void putRevents(long address, int i, short revents) {
116 int offset = SIZE_POLLFD * i + REVENTS_OFFSET;
117 UNSAFE.putShort(address + offset, revents);
118 }
119
120 static short getRevents(long address, int i) {
121 int offset = SIZE_POLLFD * i + REVENTS_OFFSET;
122 return UNSAFE.getShort(address + offset);
123 }
124
125 // -- Native methods --
126
127 private static native int pollfdSize();
128
129 private static native int fdOffset();
130
131 private static native int eventsOffset();
132
133 private static native int reventsOffset();
134
135 static native int poll(long pollAddress, int numfds, int timeout)
136 throws IOException;
137 }