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
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 private static final int SIZE_POLLFD = pollfdSize();
47 private static final int FD_OFFSET = fdOffset();
48 private static final int EVENTS_OFFSET = eventsOffset();
49 private static final int REVENTS_OFFSET = reventsOffset();
50
51 /**
52 * Allocates a poll array of {@code size} WSAPOLLFD structures.
53 */
54 static long allocatePollArray(int size) {
55 if (size <= 0)
56 throw new IllegalArgumentException();
57 return UNSAFE.allocateMemory(size * SIZE_POLLFD);
58 }
59
60 /**
61 * Reallocates a poll array from {@code size} to {@code newSize}
62 * WSAPOLLFD structures.
63 */
64 static long reallocatePollArray(long address, int size, int newSize) {
65 if (newSize < size)
66 throw new IllegalArgumentException();
67 long newAddress = allocatePollArray(newSize);
68 UNSAFE.copyMemory(address, newAddress, size * SIZE_POLLFD);
69 UNSAFE.freeMemory(address);
70 return newAddress;
71 }
72
73 /**
74 * Free a poll array.
75 */
76 static void freePollArray(long address) {
77 UNSAFE.freeMemory(address);
78 }
79
80 static void putDescriptor(long address, int i, int fd) {
81 int offset = SIZE_POLLFD * i + FD_OFFSET;
82 if (ADDRESS_SIZE == 8) {
83 UNSAFE.putLong(address + offset, fd);
84 } else {
85 UNSAFE.putInt(address + offset, fd);
86 }
87 }
88
89 static int getDescriptor(long address, int i) {
90 int offset = SIZE_POLLFD * i + FD_OFFSET;
91 long s;
92 if (ADDRESS_SIZE == 8) {
93 s = UNSAFE.getLong(address + offset);
94 } else {
95 s = UNSAFE.getInt(address + offset);
96 }
97 int fd = (int) s;
98 assert ((long) fd) == s;
99 return fd;
100 }
101
102 static void putEvents(long address, int i, short events) {
103 int offset = SIZE_POLLFD * i + EVENTS_OFFSET;
104 UNSAFE.putShort(address + offset, events);
105 }
106
107 static short getEvents(long address, int i) {
108 int offset = SIZE_POLLFD * i + EVENTS_OFFSET;
109 return UNSAFE.getShort(address + offset);
110 }
111
112 static void putRevents(long address, int i, short revents) {
113 int offset = SIZE_POLLFD * i + REVENTS_OFFSET;
114 UNSAFE.putShort(address + offset, revents);
115 }
116
117 static short getRevents(long address, int i) {
118 int offset = SIZE_POLLFD * i + REVENTS_OFFSET;
119 return UNSAFE.getShort(address + offset);
120 }
121
122 // -- Native methods --
123
124 private static native int pollfdSize();
125
126 private static native int fdOffset();
127
128 private static native int eventsOffset();
129
130 private static native int reventsOffset();
131
132 static native int poll(long pollAddress, int numfds, int timeout)
133 throws IOException;
134
135 static {
136 IOUtil.load();
137 }
138 }