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comparison: ipc/chromium/src/third_party/libevent/devpoll.c
ipc/chromium/src/third_party/libevent/devpoll.c
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| 1 /* | |
| 2 * Copyright 2000-2009 Niels Provos <provos@citi.umich.edu> | |
| 3 * Copyright 2009-2012 Niels Provos and Nick Mathewson | |
| 4 * | |
| 5 * Redistribution and use in source and binary forms, with or without | |
| 6 * modification, are permitted provided that the following conditions | |
| 7 * are met: | |
| 8 * 1. Redistributions of source code must retain the above copyright | |
| 9 * notice, this list of conditions and the following disclaimer. | |
| 10 * 2. Redistributions in binary form must reproduce the above copyright | |
| 11 * notice, this list of conditions and the following disclaimer in the | |
| 12 * documentation and/or other materials provided with the distribution. | |
| 13 * 3. The name of the author may not be used to endorse or promote products | |
| 14 * derived from this software without specific prior written permission. | |
| 15 * | |
| 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
| 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
| 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
| 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
| 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
| 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
| 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 26 */ | |
| 27 #include "event2/event-config.h" | |
| 28 | |
| 29 #include <sys/types.h> | |
| 30 #include <sys/resource.h> | |
| 31 #ifdef _EVENT_HAVE_SYS_TIME_H | |
| 32 #include <sys/time.h> | |
| 33 #endif | |
| 34 #include <sys/queue.h> | |
| 35 #include <sys/devpoll.h> | |
| 36 #include <signal.h> | |
| 37 #include <stdio.h> | |
| 38 #include <stdlib.h> | |
| 39 #include <string.h> | |
| 40 #include <unistd.h> | |
| 41 #include <fcntl.h> | |
| 42 #include <errno.h> | |
| 43 | |
| 44 #include "event2/event.h" | |
| 45 #include "event2/event_struct.h" | |
| 46 #include "event2/thread.h" | |
| 47 #include "event-internal.h" | |
| 48 #include "evsignal-internal.h" | |
| 49 #include "log-internal.h" | |
| 50 #include "evmap-internal.h" | |
| 51 #include "evthread-internal.h" | |
| 52 | |
| 53 struct devpollop { | |
| 54 struct pollfd *events; | |
| 55 int nevents; | |
| 56 int dpfd; | |
| 57 struct pollfd *changes; | |
| 58 int nchanges; | |
| 59 }; | |
| 60 | |
| 61 static void *devpoll_init(struct event_base *); | |
| 62 static int devpoll_add(struct event_base *, int fd, short old, short events, void *); | |
| 63 static int devpoll_del(struct event_base *, int fd, short old, short events, void *); | |
| 64 static int devpoll_dispatch(struct event_base *, struct timeval *); | |
| 65 static void devpoll_dealloc(struct event_base *); | |
| 66 | |
| 67 const struct eventop devpollops = { | |
| 68 "devpoll", | |
| 69 devpoll_init, | |
| 70 devpoll_add, | |
| 71 devpoll_del, | |
| 72 devpoll_dispatch, | |
| 73 devpoll_dealloc, | |
| 74 1, /* need reinit */ | |
| 75 EV_FEATURE_FDS|EV_FEATURE_O1, | |
| 76 0 | |
| 77 }; | |
| 78 | |
| 79 #define NEVENT 32000 | |
| 80 | |
| 81 static int | |
| 82 devpoll_commit(struct devpollop *devpollop) | |
| 83 { | |
| 84 /* | |
| 85 * Due to a bug in Solaris, we have to use pwrite with an offset of 0. | |
| 86 * Write is limited to 2GB of data, until it will fail. | |
| 87 */ | |
| 88 if (pwrite(devpollop->dpfd, devpollop->changes, | |
| 89 sizeof(struct pollfd) * devpollop->nchanges, 0) == -1) | |
| 90 return (-1); | |
| 91 | |
| 92 devpollop->nchanges = 0; | |
| 93 return (0); | |
| 94 } | |
| 95 | |
| 96 static int | |
| 97 devpoll_queue(struct devpollop *devpollop, int fd, int events) { | |
| 98 struct pollfd *pfd; | |
| 99 | |
| 100 if (devpollop->nchanges >= devpollop->nevents) { | |
| 101 /* | |
| 102 * Change buffer is full, must commit it to /dev/poll before | |
| 103 * adding more | |
| 104 */ | |
| 105 if (devpoll_commit(devpollop) != 0) | |
| 106 return (-1); | |
| 107 } | |
| 108 | |
| 109 pfd = &devpollop->changes[devpollop->nchanges++]; | |
| 110 pfd->fd = fd; | |
| 111 pfd->events = events; | |
| 112 pfd->revents = 0; | |
| 113 | |
| 114 return (0); | |
| 115 } | |
| 116 | |
| 117 static void * | |
| 118 devpoll_init(struct event_base *base) | |
| 119 { | |
| 120 int dpfd, nfiles = NEVENT; | |
| 121 struct rlimit rl; | |
| 122 struct devpollop *devpollop; | |
| 123 | |
| 124 if (!(devpollop = mm_calloc(1, sizeof(struct devpollop)))) | |
| 125 return (NULL); | |
| 126 | |
| 127 if (getrlimit(RLIMIT_NOFILE, &rl) == 0 && | |
| 128 rl.rlim_cur != RLIM_INFINITY) | |
| 129 nfiles = rl.rlim_cur; | |
| 130 | |
| 131 /* Initialize the kernel queue */ | |
| 132 if ((dpfd = evutil_open_closeonexec("/dev/poll", O_RDWR, 0)) == -1) { | |
| 133 event_warn("open: /dev/poll"); | |
| 134 mm_free(devpollop); | |
| 135 return (NULL); | |
| 136 } | |
| 137 | |
| 138 devpollop->dpfd = dpfd; | |
| 139 | |
| 140 /* Initialize fields */ | |
| 141 /* FIXME: allocating 'nfiles' worth of space here can be | |
| 142 * expensive and unnecessary. See how epoll.c does it instead. */ | |
| 143 devpollop->events = mm_calloc(nfiles, sizeof(struct pollfd)); | |
| 144 if (devpollop->events == NULL) { | |
| 145 mm_free(devpollop); | |
| 146 close(dpfd); | |
| 147 return (NULL); | |
| 148 } | |
| 149 devpollop->nevents = nfiles; | |
| 150 | |
| 151 devpollop->changes = mm_calloc(nfiles, sizeof(struct pollfd)); | |
| 152 if (devpollop->changes == NULL) { | |
| 153 mm_free(devpollop->events); | |
| 154 mm_free(devpollop); | |
| 155 close(dpfd); | |
| 156 return (NULL); | |
| 157 } | |
| 158 | |
| 159 evsig_init(base); | |
| 160 | |
| 161 return (devpollop); | |
| 162 } | |
| 163 | |
| 164 static int | |
| 165 devpoll_dispatch(struct event_base *base, struct timeval *tv) | |
| 166 { | |
| 167 struct devpollop *devpollop = base->evbase; | |
| 168 struct pollfd *events = devpollop->events; | |
| 169 struct dvpoll dvp; | |
| 170 int i, res, timeout = -1; | |
| 171 | |
| 172 if (devpollop->nchanges) | |
| 173 devpoll_commit(devpollop); | |
| 174 | |
| 175 if (tv != NULL) | |
| 176 timeout = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000; | |
| 177 | |
| 178 dvp.dp_fds = devpollop->events; | |
| 179 dvp.dp_nfds = devpollop->nevents; | |
| 180 dvp.dp_timeout = timeout; | |
| 181 | |
| 182 EVBASE_RELEASE_LOCK(base, th_base_lock); | |
| 183 | |
| 184 res = ioctl(devpollop->dpfd, DP_POLL, &dvp); | |
| 185 | |
| 186 EVBASE_ACQUIRE_LOCK(base, th_base_lock); | |
| 187 | |
| 188 if (res == -1) { | |
| 189 if (errno != EINTR) { | |
| 190 event_warn("ioctl: DP_POLL"); | |
| 191 return (-1); | |
| 192 } | |
| 193 | |
| 194 return (0); | |
| 195 } | |
| 196 | |
| 197 event_debug(("%s: devpoll_wait reports %d", __func__, res)); | |
| 198 | |
| 199 for (i = 0; i < res; i++) { | |
| 200 int which = 0; | |
| 201 int what = events[i].revents; | |
| 202 | |
| 203 if (what & POLLHUP) | |
| 204 what |= POLLIN | POLLOUT; | |
| 205 else if (what & POLLERR) | |
| 206 what |= POLLIN | POLLOUT; | |
| 207 | |
| 208 if (what & POLLIN) | |
| 209 which |= EV_READ; | |
| 210 if (what & POLLOUT) | |
| 211 which |= EV_WRITE; | |
| 212 | |
| 213 if (!which) | |
| 214 continue; | |
| 215 | |
| 216 /* XXX(niels): not sure if this works for devpoll */ | |
| 217 evmap_io_active(base, events[i].fd, which); | |
| 218 } | |
| 219 | |
| 220 return (0); | |
| 221 } | |
| 222 | |
| 223 | |
| 224 static int | |
| 225 devpoll_add(struct event_base *base, int fd, short old, short events, void *p) | |
| 226 { | |
| 227 struct devpollop *devpollop = base->evbase; | |
| 228 int res; | |
| 229 (void)p; | |
| 230 | |
| 231 /* | |
| 232 * It's not necessary to OR the existing read/write events that we | |
| 233 * are currently interested in with the new event we are adding. | |
| 234 * The /dev/poll driver ORs any new events with the existing events | |
| 235 * that it has cached for the fd. | |
| 236 */ | |
| 237 | |
| 238 res = 0; | |
| 239 if (events & EV_READ) | |
| 240 res |= POLLIN; | |
| 241 if (events & EV_WRITE) | |
| 242 res |= POLLOUT; | |
| 243 | |
| 244 if (devpoll_queue(devpollop, fd, res) != 0) | |
| 245 return (-1); | |
| 246 | |
| 247 return (0); | |
| 248 } | |
| 249 | |
| 250 static int | |
| 251 devpoll_del(struct event_base *base, int fd, short old, short events, void *p) | |
| 252 { | |
| 253 struct devpollop *devpollop = base->evbase; | |
| 254 int res; | |
| 255 (void)p; | |
| 256 | |
| 257 res = 0; | |
| 258 if (events & EV_READ) | |
| 259 res |= POLLIN; | |
| 260 if (events & EV_WRITE) | |
| 261 res |= POLLOUT; | |
| 262 | |
| 263 /* | |
| 264 * The only way to remove an fd from the /dev/poll monitored set is | |
| 265 * to use POLLREMOVE by itself. This removes ALL events for the fd | |
| 266 * provided so if we care about two events and are only removing one | |
| 267 * we must re-add the other event after POLLREMOVE. | |
| 268 */ | |
| 269 | |
| 270 if (devpoll_queue(devpollop, fd, POLLREMOVE) != 0) | |
| 271 return (-1); | |
| 272 | |
| 273 if ((res & (POLLIN|POLLOUT)) != (POLLIN|POLLOUT)) { | |
| 274 /* | |
| 275 * We're not deleting all events, so we must resubmit the | |
| 276 * event that we are still interested in if one exists. | |
| 277 */ | |
| 278 | |
| 279 if ((res & POLLIN) && (old & EV_WRITE)) { | |
| 280 /* Deleting read, still care about write */ | |
| 281 devpoll_queue(devpollop, fd, POLLOUT); | |
| 282 } else if ((res & POLLOUT) && (old & EV_READ)) { | |
| 283 /* Deleting write, still care about read */ | |
| 284 devpoll_queue(devpollop, fd, POLLIN); | |
| 285 } | |
| 286 } | |
| 287 | |
| 288 return (0); | |
| 289 } | |
| 290 | |
| 291 static void | |
| 292 devpoll_dealloc(struct event_base *base) | |
| 293 { | |
| 294 struct devpollop *devpollop = base->evbase; | |
| 295 | |
| 296 evsig_dealloc(base); | |
| 297 if (devpollop->events) | |
| 298 mm_free(devpollop->events); | |
| 299 if (devpollop->changes) | |
| 300 mm_free(devpollop->changes); | |
| 301 if (devpollop->dpfd >= 0) | |
| 302 close(devpollop->dpfd); | |
| 303 | |
| 304 memset(devpollop, 0, sizeof(struct devpollop)); | |
| 305 mm_free(devpollop); | |
| 306 } |
