J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2005-2007 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.nio.ch; |
| 27 | |
| 28 | import java.io.IOException; |
| 29 | import java.util.LinkedList; |
| 30 | import java.util.HashSet; |
| 31 | |
| 32 | /** |
| 33 | * Manipulates a native array of epoll_event structs on Linux: |
| 34 | * |
| 35 | * typedef union epoll_data { |
| 36 | * void *ptr; |
| 37 | * int fd; |
| 38 | * __uint32_t u32; |
| 39 | * __uint64_t u64; |
| 40 | * } epoll_data_t; |
| 41 | * |
| 42 | * struct epoll_event { |
| 43 | * __uint32_t events; |
| 44 | * epoll_data_t data; |
| 45 | * }; |
| 46 | * |
| 47 | * The system call to wait for I/O events is epoll_wait(2). It populates an |
| 48 | * array of epoll_event structures that are passed to the call. The data |
| 49 | * member of the epoll_event structure contains the same data as was set |
| 50 | * when the file descriptor was registered to epoll via epoll_ctl(2). In |
| 51 | * this implementation we set data.fd to be the file descriptor that we |
| 52 | * register. That way, we have the file descriptor available when we |
| 53 | * process the events. |
| 54 | * |
| 55 | * All file descriptors registered with epoll have the POLLHUP and POLLERR |
| 56 | * events enabled even when registered with an event set of 0. To ensure |
| 57 | * that epoll_wait doesn't poll an idle file descriptor when the underlying |
| 58 | * connection is closed or reset then its registration is deleted from |
| 59 | * epoll (it will be re-added again if the event set is changed) |
| 60 | */ |
| 61 | |
| 62 | class EPollArrayWrapper { |
| 63 | // EPOLL_EVENTS |
| 64 | static final int EPOLLIN = 0x001; |
| 65 | |
| 66 | // opcodes |
| 67 | static final int EPOLL_CTL_ADD = 1; |
| 68 | static final int EPOLL_CTL_DEL = 2; |
| 69 | static final int EPOLL_CTL_MOD = 3; |
| 70 | |
| 71 | // Miscellaneous constants |
| 72 | static final short SIZE_EPOLLEVENT = 12; |
| 73 | static final short EVENT_OFFSET = 0; |
| 74 | static final short DATA_OFFSET = 4; |
| 75 | static final short FD_OFFSET = 4; |
| 76 | static final int NUM_EPOLLEVENTS = Math.min(fdLimit(), 8192); |
| 77 | |
| 78 | // Base address of the native pollArray |
| 79 | private final long pollArrayAddress; |
| 80 | |
| 81 | // Set of "idle" file descriptors |
| 82 | private final HashSet<Integer> idleSet; |
| 83 | |
| 84 | EPollArrayWrapper() { |
| 85 | // creates the epoll file descriptor |
| 86 | epfd = epollCreate(); |
| 87 | |
| 88 | // the epoll_event array passed to epoll_wait |
| 89 | int allocationSize = NUM_EPOLLEVENTS * SIZE_EPOLLEVENT; |
| 90 | pollArray = new AllocatedNativeObject(allocationSize, true); |
| 91 | pollArrayAddress = pollArray.address(); |
| 92 | |
| 93 | for (int i=0; i<NUM_EPOLLEVENTS; i++) { |
| 94 | putEventOps(i, 0); |
| 95 | putData(i, 0L); |
| 96 | } |
| 97 | |
| 98 | // create idle set |
| 99 | idleSet = new HashSet<Integer>(); |
| 100 | } |
| 101 | |
| 102 | // Used to update file description registrations |
| 103 | private static class Updator { |
| 104 | int opcode; |
| 105 | int fd; |
| 106 | int events; |
| 107 | Updator(int opcode, int fd, int events) { |
| 108 | this.opcode = opcode; |
| 109 | this.fd = fd; |
| 110 | this.events = events; |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | private LinkedList<Updator> updateList = new LinkedList<Updator>(); |
| 115 | |
| 116 | // The epoll_event array for results from epoll_wait |
| 117 | private AllocatedNativeObject pollArray; |
| 118 | |
| 119 | // The fd of the epoll driver |
| 120 | final int epfd; |
| 121 | |
| 122 | // The fd of the interrupt line going out |
| 123 | int outgoingInterruptFD; |
| 124 | |
| 125 | // The fd of the interrupt line coming in |
| 126 | int incomingInterruptFD; |
| 127 | |
| 128 | // The index of the interrupt FD |
| 129 | int interruptedIndex; |
| 130 | |
| 131 | // Number of updated pollfd entries |
| 132 | int updated; |
| 133 | |
| 134 | void initInterrupt(int fd0, int fd1) { |
| 135 | outgoingInterruptFD = fd1; |
| 136 | incomingInterruptFD = fd0; |
| 137 | epollCtl(epfd, EPOLL_CTL_ADD, fd0, EPOLLIN); |
| 138 | } |
| 139 | |
| 140 | void putEventOps(int i, int event) { |
| 141 | int offset = SIZE_EPOLLEVENT * i + EVENT_OFFSET; |
| 142 | pollArray.putInt(offset, event); |
| 143 | } |
| 144 | |
| 145 | void putData(int i, long value) { |
| 146 | int offset = SIZE_EPOLLEVENT * i + DATA_OFFSET; |
| 147 | pollArray.putLong(offset, value); |
| 148 | } |
| 149 | |
| 150 | void putDescriptor(int i, int fd) { |
| 151 | int offset = SIZE_EPOLLEVENT * i + FD_OFFSET; |
| 152 | pollArray.putInt(offset, fd); |
| 153 | } |
| 154 | |
| 155 | int getEventOps(int i) { |
| 156 | int offset = SIZE_EPOLLEVENT * i + EVENT_OFFSET; |
| 157 | return pollArray.getInt(offset); |
| 158 | } |
| 159 | |
| 160 | int getDescriptor(int i) { |
| 161 | int offset = SIZE_EPOLLEVENT * i + FD_OFFSET; |
| 162 | return pollArray.getInt(offset); |
| 163 | } |
| 164 | |
| 165 | /** |
| 166 | * Update the events for a given file descriptor. |
| 167 | */ |
| 168 | void setInterest(int fd, int mask) { |
| 169 | synchronized (updateList) { |
| 170 | |
| 171 | // if the interest events are 0 then add to idle set, and delete |
| 172 | // from epoll if registered (or pending) |
| 173 | if (mask == 0) { |
| 174 | if (idleSet.add(fd)) { |
| 175 | updateList.add(new Updator(EPOLL_CTL_DEL, fd, 0)); |
| 176 | } |
| 177 | return; |
| 178 | } |
| 179 | |
| 180 | // if file descriptor is idle then add to epoll |
| 181 | if (!idleSet.isEmpty() && idleSet.remove(fd)) { |
| 182 | updateList.add(new Updator(EPOLL_CTL_ADD, fd, mask)); |
| 183 | return; |
| 184 | } |
| 185 | |
| 186 | // if the previous pending operation is to add this file descriptor |
| 187 | // to epoll then update its event set |
| 188 | if (updateList.size() > 0) { |
| 189 | Updator last = updateList.getLast(); |
| 190 | if (last.fd == fd && last.opcode == EPOLL_CTL_ADD) { |
| 191 | last.events = mask; |
| 192 | return; |
| 193 | } |
| 194 | } |
| 195 | |
| 196 | // update existing registration |
| 197 | updateList.add(new Updator(EPOLL_CTL_MOD, fd, mask)); |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | /** |
| 202 | * Add a new file descriptor to epoll |
| 203 | */ |
| 204 | void add(int fd) { |
| 205 | synchronized (updateList) { |
| 206 | updateList.add(new Updator(EPOLL_CTL_ADD, fd, 0)); |
| 207 | } |
| 208 | } |
| 209 | |
| 210 | /** |
| 211 | * Remove a file descriptor from epoll |
| 212 | */ |
| 213 | void release(int fd) { |
| 214 | synchronized (updateList) { |
| 215 | // if file descriptor is idle then remove from idle set, otherwise |
| 216 | // delete from epoll |
| 217 | if (!idleSet.remove(fd)) { |
| 218 | updateList.add(new Updator(EPOLL_CTL_DEL, fd, 0)); |
| 219 | } |
| 220 | } |
| 221 | } |
| 222 | |
| 223 | /** |
| 224 | * Close epoll file descriptor and free poll array |
| 225 | */ |
| 226 | void closeEPollFD() throws IOException { |
| 227 | FileDispatcher.closeIntFD(epfd); |
| 228 | pollArray.free(); |
| 229 | } |
| 230 | |
| 231 | int poll(long timeout) throws IOException { |
| 232 | updateRegistrations(); |
| 233 | updated = epollWait(pollArrayAddress, NUM_EPOLLEVENTS, timeout, epfd); |
| 234 | for (int i=0; i<updated; i++) { |
| 235 | if (getDescriptor(i) == incomingInterruptFD) { |
| 236 | interruptedIndex = i; |
| 237 | interrupted = true; |
| 238 | break; |
| 239 | } |
| 240 | } |
| 241 | return updated; |
| 242 | } |
| 243 | |
| 244 | /** |
| 245 | * Update the pending registrations. |
| 246 | */ |
| 247 | void updateRegistrations() { |
| 248 | synchronized (updateList) { |
| 249 | Updator u = null; |
| 250 | while ((u = updateList.poll()) != null) { |
| 251 | epollCtl(epfd, u.opcode, u.fd, u.events); |
| 252 | } |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | // interrupt support |
| 257 | boolean interrupted = false; |
| 258 | |
| 259 | public void interrupt() { |
| 260 | interrupt(outgoingInterruptFD); |
| 261 | } |
| 262 | |
| 263 | public int interruptedIndex() { |
| 264 | return interruptedIndex; |
| 265 | } |
| 266 | |
| 267 | boolean interrupted() { |
| 268 | return interrupted; |
| 269 | } |
| 270 | |
| 271 | void clearInterrupted() { |
| 272 | interrupted = false; |
| 273 | } |
| 274 | |
| 275 | static { |
| 276 | init(); |
| 277 | } |
| 278 | |
| 279 | private native int epollCreate(); |
| 280 | private native void epollCtl(int epfd, int opcode, int fd, int events); |
| 281 | private native int epollWait(long pollAddress, int numfds, long timeout, |
| 282 | int epfd) throws IOException; |
| 283 | private static native int fdLimit(); |
| 284 | private static native void interrupt(int fd); |
| 285 | private static native void init(); |
| 286 | } |