1 /* 2 * Copyright (c) 2008, 2018, 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 jdk.internal.misc.Unsafe; 30 31 /** 32 * Provides access to the Linux epoll facility. 33 */ 34 35 class EPoll { EPoll()36 private EPoll() { } 37 38 private static final Unsafe unsafe = Unsafe.getUnsafe(); 39 40 /** 41 * typedef union epoll_data { 42 * void *ptr; 43 * int fd; 44 * __uint32_t u32; 45 * __uint64_t u64; 46 * } epoll_data_t; 47 * 48 * struct epoll_event { 49 * __uint32_t events; 50 * epoll_data_t data; 51 * } 52 */ 53 private static final int SIZEOF_EPOLLEVENT = eventSize(); 54 private static final int OFFSETOF_EVENTS = eventsOffset(); 55 private static final int OFFSETOF_FD = dataOffset(); 56 57 // opcodes 58 static final int EPOLL_CTL_ADD = 1; 59 static final int EPOLL_CTL_DEL = 2; 60 static final int EPOLL_CTL_MOD = 3; 61 62 // events 63 static final int EPOLLIN = 0x1; 64 static final int EPOLLOUT = 0x4; 65 66 // flags 67 static final int EPOLLONESHOT = (1 << 30); 68 69 /** 70 * Allocates a poll array to handle up to {@code count} events. 71 */ allocatePollArray(int count)72 static long allocatePollArray(int count) { 73 return unsafe.allocateMemory(count * SIZEOF_EPOLLEVENT); 74 } 75 76 /** 77 * Free a poll array 78 */ freePollArray(long address)79 static void freePollArray(long address) { 80 unsafe.freeMemory(address); 81 } 82 83 /** 84 * Returns event[i]; 85 */ getEvent(long address, int i)86 static long getEvent(long address, int i) { 87 return address + (SIZEOF_EPOLLEVENT*i); 88 } 89 90 /** 91 * Returns event->data.fd 92 */ getDescriptor(long eventAddress)93 static int getDescriptor(long eventAddress) { 94 return unsafe.getInt(eventAddress + OFFSETOF_FD); 95 } 96 97 /** 98 * Returns event->events 99 */ getEvents(long eventAddress)100 static int getEvents(long eventAddress) { 101 return unsafe.getInt(eventAddress + OFFSETOF_EVENTS); 102 } 103 104 // -- Native methods -- 105 eventSize()106 private static native int eventSize(); 107 eventsOffset()108 private static native int eventsOffset(); 109 dataOffset()110 private static native int dataOffset(); 111 create()112 static native int create() throws IOException; 113 ctl(int epfd, int opcode, int fd, int events)114 static native int ctl(int epfd, int opcode, int fd, int events); 115 wait(int epfd, long pollAddress, int numfds, int timeout)116 static native int wait(int epfd, long pollAddress, int numfds, int timeout) 117 throws IOException; 118 119 static { IOUtil.load()120 IOUtil.load(); 121 } 122 } 123