pollevent.cc revision 2665:a124942bacb8
1/* 2 * Copyright (c) 2002-2005 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * Authors: Nathan Binkert 29 */ 30 31#include <sys/ioctl.h> 32#include <sys/types.h> 33 34#include <fcntl.h> 35#include <signal.h> 36#include <unistd.h> 37 38#include "sim/async.hh" 39#include "sim/host.hh" 40#include "base/misc.hh" 41#include "base/pollevent.hh" 42#include "sim/root.hh" 43#include "sim/serialize.hh" 44 45using namespace std; 46 47PollQueue pollQueue; 48 49///////////////////////////////////////////////////// 50// 51PollEvent::PollEvent(int _fd, int _events) 52 : queue(NULL), enabled(true) 53{ 54 pfd.fd = _fd; 55 pfd.events = _events; 56} 57 58PollEvent::~PollEvent() 59{ 60 if (queue) 61 queue->remove(this); 62} 63 64void 65PollEvent::disable() 66{ 67 if (!enabled) return; 68 enabled = false; 69 70 if (queue) 71 queue->copy(); 72} 73 74void 75PollEvent::enable() 76{ 77 if (enabled) return; 78 enabled = true; 79 80 if (queue) 81 queue->copy(); 82} 83 84void 85PollEvent::serialize(ostream &os) 86{ 87 SERIALIZE_SCALAR(pfd.fd); 88 SERIALIZE_SCALAR(pfd.events); 89 SERIALIZE_SCALAR(enabled); 90} 91 92void 93PollEvent::unserialize(Checkpoint *cp, const std::string §ion) 94{ 95 UNSERIALIZE_SCALAR(pfd.fd); 96 UNSERIALIZE_SCALAR(pfd.events); 97 UNSERIALIZE_SCALAR(enabled); 98} 99 100///////////////////////////////////////////////////// 101// 102PollQueue::PollQueue() 103 : poll_fds(NULL), max_size(0), num_fds(0) 104{ } 105 106PollQueue::~PollQueue() 107{ 108 removeHandler(); 109 for (int i = 0; i < num_fds; i++) 110 setupAsyncIO(poll_fds[0].fd, false); 111 112 delete [] poll_fds; 113} 114 115void 116PollQueue::copy() 117{ 118 eventvec_t::iterator i = events.begin(); 119 eventvec_t::iterator end = events.end(); 120 121 num_fds = 0; 122 123 while (i < end) { 124 if ((*i)->enabled) 125 poll_fds[num_fds++] = (*i)->pfd; 126 ++i; 127 } 128} 129 130void 131PollQueue::remove(PollEvent *event) 132{ 133 eventvec_t::iterator i = events.begin(); 134 eventvec_t::iterator end = events.end(); 135 136 while (i < end) { 137 if (*i == event) { 138 events.erase(i); 139 copy(); 140 event->queue = NULL; 141 return; 142 } 143 144 ++i; 145 } 146 147 panic("Event does not exist. Cannot remove."); 148} 149 150void 151PollQueue::schedule(PollEvent *event) 152{ 153 if (event->queue) 154 panic("Event already scheduled!"); 155 156 event->queue = this; 157 events.push_back(event); 158 setupAsyncIO(event->pfd.fd, true); 159 160 // if we ran out of space in the fd array, double the capacity 161 // if this is the first time that we've scheduled an event, create 162 // the array with an initial size of 16 163 if (++num_fds > max_size) { 164 if (max_size > 0) { 165 delete [] poll_fds; 166 max_size *= 2; 167 } else { 168 max_size = 16; 169 setupHandler(); 170 } 171 172 poll_fds = new pollfd[max_size]; 173 } 174 175 copy(); 176} 177 178void 179PollQueue::service() 180{ 181 int ret = poll(poll_fds, num_fds, 0); 182 183 if (ret <= 0) 184 return; 185 186 for (int i = 0; i < num_fds; i++) { 187 int revents = poll_fds[i].revents; 188 if (revents) { 189 events[i]->process(revents); 190 if (--ret <= 0) 191 break; 192 } 193 } 194} 195 196struct sigaction PollQueue::oldio; 197struct sigaction PollQueue::oldalrm; 198bool PollQueue::handler = false; 199 200void 201PollQueue::setupAsyncIO(int fd, bool set) 202{ 203 int flags = fcntl(fd, F_GETFL); 204 if (flags == -1) 205 panic("Could not set up async IO"); 206 207 if (set) 208 flags |= FASYNC; 209 else 210 flags &= ~(FASYNC); 211 212 if (fcntl(fd, F_SETFL, flags) == -1) 213 panic("Could not set up async IO"); 214 215 if (set) { 216 if (fcntl(fd, F_SETOWN, getpid()) == -1) 217 panic("Could not set up async IO"); 218 } 219} 220 221void 222PollQueue::setupHandler() 223{ 224 struct sigaction act; 225 226 act.sa_handler = handleIO; 227 sigemptyset(&act.sa_mask); 228 act.sa_flags = SA_RESTART; 229 230 if (sigaction(SIGIO, &act, &oldio) == -1) 231 panic("could not do sigaction"); 232 233 act.sa_handler = handleALRM; 234 sigemptyset(&act.sa_mask); 235 act.sa_flags = SA_RESTART; 236 237 if (sigaction(SIGALRM, &act, &oldalrm) == -1) 238 panic("could not do sigaction"); 239 240 alarm(1); 241 242 handler = true; 243} 244 245void 246PollQueue::removeHandler() 247{ 248 if (sigaction(SIGIO, &oldio, NULL) == -1) 249 panic("could not remove handler"); 250 251 if (sigaction(SIGIO, &oldalrm, NULL) == -1) 252 panic("could not remove handler"); 253} 254 255void 256PollQueue::handleIO(int sig) 257{ 258 if (sig != SIGIO) 259 panic("Wrong Handler"); 260 261 async_event = true; 262 async_io = true; 263} 264 265void 266PollQueue::handleALRM(int sig) 267{ 268 if (sig != SIGALRM) 269 panic("Wrong Handler"); 270 271 async_event = true; 272 async_alarm = true; 273 alarm(1); 274} 275 276