1 /* $NetBSD: devpoll.c,v 1.1.1.2 2017/01/31 21:14:52 christos Exp $ */ 2 /* 3 * Copyright 2000-2009 Niels Provos <provos@citi.umich.edu> 4 * Copyright 2009-2012 Niels Provos and Nick Mathewson 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT 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 OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 #include "event2/event-config.h" 29 #include <sys/cdefs.h> 30 __RCSID("$NetBSD: devpoll.c,v 1.1.1.2 2017/01/31 21:14:52 christos Exp $"); 31 #include "evconfig-private.h" 32 33 #ifdef EVENT__HAVE_DEVPOLL 34 35 #include <sys/types.h> 36 #include <sys/resource.h> 37 #ifdef EVENT__HAVE_SYS_TIME_H 38 #include <sys/time.h> 39 #endif 40 #include <sys/queue.h> 41 #include <sys/devpoll.h> 42 #include <signal.h> 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <unistd.h> 47 #include <fcntl.h> 48 #include <errno.h> 49 50 #include "event2/event.h" 51 #include "event2/event_struct.h" 52 #include "event2/thread.h" 53 #include "event-internal.h" 54 #include "evsignal-internal.h" 55 #include "log-internal.h" 56 #include "evmap-internal.h" 57 #include "evthread-internal.h" 58 59 struct devpollop { 60 struct pollfd *events; 61 int nevents; 62 int dpfd; 63 struct pollfd *changes; 64 int nchanges; 65 }; 66 67 static void *devpoll_init(struct event_base *); 68 static int devpoll_add(struct event_base *, int fd, short old, short events, void *); 69 static int devpoll_del(struct event_base *, int fd, short old, short events, void *); 70 static int devpoll_dispatch(struct event_base *, struct timeval *); 71 static void devpoll_dealloc(struct event_base *); 72 73 const struct eventop devpollops = { 74 "devpoll", 75 devpoll_init, 76 devpoll_add, 77 devpoll_del, 78 devpoll_dispatch, 79 devpoll_dealloc, 80 1, /* need reinit */ 81 EV_FEATURE_FDS|EV_FEATURE_O1, 82 0 83 }; 84 85 #define NEVENT 32000 86 87 static int 88 devpoll_commit(struct devpollop *devpollop) 89 { 90 /* 91 * Due to a bug in Solaris, we have to use pwrite with an offset of 0. 92 * Write is limited to 2GB of data, until it will fail. 93 */ 94 if (pwrite(devpollop->dpfd, devpollop->changes, 95 sizeof(struct pollfd) * devpollop->nchanges, 0) == -1) 96 return (-1); 97 98 devpollop->nchanges = 0; 99 return (0); 100 } 101 102 static int 103 devpoll_queue(struct devpollop *devpollop, int fd, int events) { 104 struct pollfd *pfd; 105 106 if (devpollop->nchanges >= devpollop->nevents) { 107 /* 108 * Change buffer is full, must commit it to /dev/poll before 109 * adding more 110 */ 111 if (devpoll_commit(devpollop) != 0) 112 return (-1); 113 } 114 115 pfd = &devpollop->changes[devpollop->nchanges++]; 116 pfd->fd = fd; 117 pfd->events = events; 118 pfd->revents = 0; 119 120 return (0); 121 } 122 123 static void * 124 devpoll_init(struct event_base *base) 125 { 126 int dpfd, nfiles = NEVENT; 127 struct rlimit rl; 128 struct devpollop *devpollop; 129 130 if (!(devpollop = mm_calloc(1, sizeof(struct devpollop)))) 131 return (NULL); 132 133 if (getrlimit(RLIMIT_NOFILE, &rl) == 0 && 134 rl.rlim_cur != RLIM_INFINITY) 135 nfiles = rl.rlim_cur; 136 137 /* Initialize the kernel queue */ 138 if ((dpfd = evutil_open_closeonexec_("/dev/poll", O_RDWR, 0)) == -1) { 139 event_warn("open: /dev/poll"); 140 mm_free(devpollop); 141 return (NULL); 142 } 143 144 devpollop->dpfd = dpfd; 145 146 /* Initialize fields */ 147 /* FIXME: allocating 'nfiles' worth of space here can be 148 * expensive and unnecessary. See how epoll.c does it instead. */ 149 devpollop->events = mm_calloc(nfiles, sizeof(struct pollfd)); 150 if (devpollop->events == NULL) { 151 mm_free(devpollop); 152 close(dpfd); 153 return (NULL); 154 } 155 devpollop->nevents = nfiles; 156 157 devpollop->changes = mm_calloc(nfiles, sizeof(struct pollfd)); 158 if (devpollop->changes == NULL) { 159 mm_free(devpollop->events); 160 mm_free(devpollop); 161 close(dpfd); 162 return (NULL); 163 } 164 165 evsig_init_(base); 166 167 return (devpollop); 168 } 169 170 static int 171 devpoll_dispatch(struct event_base *base, struct timeval *tv) 172 { 173 struct devpollop *devpollop = base->evbase; 174 struct pollfd *events = devpollop->events; 175 struct dvpoll dvp; 176 int i, res, timeout = -1; 177 178 if (devpollop->nchanges) 179 devpoll_commit(devpollop); 180 181 if (tv != NULL) 182 timeout = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000; 183 184 dvp.dp_fds = devpollop->events; 185 dvp.dp_nfds = devpollop->nevents; 186 dvp.dp_timeout = timeout; 187 188 EVBASE_RELEASE_LOCK(base, th_base_lock); 189 190 res = ioctl(devpollop->dpfd, DP_POLL, &dvp); 191 192 EVBASE_ACQUIRE_LOCK(base, th_base_lock); 193 194 if (res == -1) { 195 if (errno != EINTR) { 196 event_warn("ioctl: DP_POLL"); 197 return (-1); 198 } 199 200 return (0); 201 } 202 203 event_debug(("%s: devpoll_wait reports %d", __func__, res)); 204 205 for (i = 0; i < res; i++) { 206 int which = 0; 207 int what = events[i].revents; 208 209 if (what & POLLHUP) 210 what |= POLLIN | POLLOUT; 211 else if (what & POLLERR) 212 what |= POLLIN | POLLOUT; 213 214 if (what & POLLIN) 215 which |= EV_READ; 216 if (what & POLLOUT) 217 which |= EV_WRITE; 218 219 if (!which) 220 continue; 221 222 /* XXX(niels): not sure if this works for devpoll */ 223 evmap_io_active_(base, events[i].fd, which); 224 } 225 226 return (0); 227 } 228 229 230 static int 231 devpoll_add(struct event_base *base, int fd, short old, short events, void *p) 232 { 233 struct devpollop *devpollop = base->evbase; 234 int res; 235 (void)p; 236 237 /* 238 * It's not necessary to OR the existing read/write events that we 239 * are currently interested in with the new event we are adding. 240 * The /dev/poll driver ORs any new events with the existing events 241 * that it has cached for the fd. 242 */ 243 244 res = 0; 245 if (events & EV_READ) 246 res |= POLLIN; 247 if (events & EV_WRITE) 248 res |= POLLOUT; 249 250 if (devpoll_queue(devpollop, fd, res) != 0) 251 return (-1); 252 253 return (0); 254 } 255 256 static int 257 devpoll_del(struct event_base *base, int fd, short old, short events, void *p) 258 { 259 struct devpollop *devpollop = base->evbase; 260 int res; 261 (void)p; 262 263 res = 0; 264 if (events & EV_READ) 265 res |= POLLIN; 266 if (events & EV_WRITE) 267 res |= POLLOUT; 268 269 /* 270 * The only way to remove an fd from the /dev/poll monitored set is 271 * to use POLLREMOVE by itself. This removes ALL events for the fd 272 * provided so if we care about two events and are only removing one 273 * we must re-add the other event after POLLREMOVE. 274 */ 275 276 if (devpoll_queue(devpollop, fd, POLLREMOVE) != 0) 277 return (-1); 278 279 if ((res & (POLLIN|POLLOUT)) != (POLLIN|POLLOUT)) { 280 /* 281 * We're not deleting all events, so we must resubmit the 282 * event that we are still interested in if one exists. 283 */ 284 285 if ((res & POLLIN) && (old & EV_WRITE)) { 286 /* Deleting read, still care about write */ 287 devpoll_queue(devpollop, fd, POLLOUT); 288 } else if ((res & POLLOUT) && (old & EV_READ)) { 289 /* Deleting write, still care about read */ 290 devpoll_queue(devpollop, fd, POLLIN); 291 } 292 } 293 294 return (0); 295 } 296 297 static void 298 devpoll_dealloc(struct event_base *base) 299 { 300 struct devpollop *devpollop = base->evbase; 301 302 evsig_dealloc_(base); 303 if (devpollop->events) 304 mm_free(devpollop->events); 305 if (devpollop->changes) 306 mm_free(devpollop->changes); 307 if (devpollop->dpfd >= 0) 308 close(devpollop->dpfd); 309 310 memset(devpollop, 0, sizeof(struct devpollop)); 311 mm_free(devpollop); 312 } 313 314 #endif /* EVENT__HAVE_DEVPOLL */ 315