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comparison: ipc/chromium/src/third_party/libevent/poll.c
ipc/chromium/src/third_party/libevent/poll.c
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- changeset 6
- 8bccb770b82d
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| -1:000000000000 | 0:3786a95cfd90 |
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| 1 /* $OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */ | |
| 2 | |
| 3 /* | |
| 4 * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu> | |
| 5 * Copyright 2007-2012 Niels Provos and Nick Mathewson | |
| 6 * | |
| 7 * Redistribution and use in source and binary forms, with or without | |
| 8 * modification, are permitted provided that the following conditions | |
| 9 * are met: | |
| 10 * 1. Redistributions of source code must retain the above copyright | |
| 11 * notice, this list of conditions and the following disclaimer. | |
| 12 * 2. Redistributions in binary form must reproduce the above copyright | |
| 13 * notice, this list of conditions and the following disclaimer in the | |
| 14 * documentation and/or other materials provided with the distribution. | |
| 15 * 3. The name of the author may not be used to endorse or promote products | |
| 16 * derived from this software without specific prior written permission. | |
| 17 * | |
| 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
| 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
| 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
| 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
| 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
| 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
| 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 28 */ | |
| 29 #include "event2/event-config.h" | |
| 30 | |
| 31 #include <sys/types.h> | |
| 32 #ifdef _EVENT_HAVE_SYS_TIME_H | |
| 33 #include <sys/time.h> | |
| 34 #endif | |
| 35 #include <sys/queue.h> | |
| 36 #include <poll.h> | |
| 37 #include <signal.h> | |
| 38 #include <limits.h> | |
| 39 #include <stdio.h> | |
| 40 #include <stdlib.h> | |
| 41 #include <string.h> | |
| 42 #include <unistd.h> | |
| 43 #include <errno.h> | |
| 44 | |
| 45 #include "event-internal.h" | |
| 46 #include "evsignal-internal.h" | |
| 47 #include "log-internal.h" | |
| 48 #include "evmap-internal.h" | |
| 49 #include "event2/thread.h" | |
| 50 #include "evthread-internal.h" | |
| 51 | |
| 52 struct pollidx { | |
| 53 int idxplus1; | |
| 54 }; | |
| 55 | |
| 56 struct pollop { | |
| 57 int event_count; /* Highest number alloc */ | |
| 58 int nfds; /* Highest number used */ | |
| 59 int realloc_copy; /* True iff we must realloc | |
| 60 * event_set_copy */ | |
| 61 struct pollfd *event_set; | |
| 62 struct pollfd *event_set_copy; | |
| 63 }; | |
| 64 | |
| 65 static void *poll_init(struct event_base *); | |
| 66 static int poll_add(struct event_base *, int, short old, short events, void *_idx); | |
| 67 static int poll_del(struct event_base *, int, short old, short events, void *_idx); | |
| 68 static int poll_dispatch(struct event_base *, struct timeval *); | |
| 69 static void poll_dealloc(struct event_base *); | |
| 70 | |
| 71 const struct eventop pollops = { | |
| 72 "poll", | |
| 73 poll_init, | |
| 74 poll_add, | |
| 75 poll_del, | |
| 76 poll_dispatch, | |
| 77 poll_dealloc, | |
| 78 0, /* doesn't need_reinit */ | |
| 79 EV_FEATURE_FDS, | |
| 80 sizeof(struct pollidx), | |
| 81 }; | |
| 82 | |
| 83 static void * | |
| 84 poll_init(struct event_base *base) | |
| 85 { | |
| 86 struct pollop *pollop; | |
| 87 | |
| 88 if (!(pollop = mm_calloc(1, sizeof(struct pollop)))) | |
| 89 return (NULL); | |
| 90 | |
| 91 evsig_init(base); | |
| 92 | |
| 93 return (pollop); | |
| 94 } | |
| 95 | |
| 96 #ifdef CHECK_INVARIANTS | |
| 97 static void | |
| 98 poll_check_ok(struct pollop *pop) | |
| 99 { | |
| 100 int i, idx; | |
| 101 struct event *ev; | |
| 102 | |
| 103 for (i = 0; i < pop->fd_count; ++i) { | |
| 104 idx = pop->idxplus1_by_fd[i]-1; | |
| 105 if (idx < 0) | |
| 106 continue; | |
| 107 EVUTIL_ASSERT(pop->event_set[idx].fd == i); | |
| 108 } | |
| 109 for (i = 0; i < pop->nfds; ++i) { | |
| 110 struct pollfd *pfd = &pop->event_set[i]; | |
| 111 EVUTIL_ASSERT(pop->idxplus1_by_fd[pfd->fd] == i+1); | |
| 112 } | |
| 113 } | |
| 114 #else | |
| 115 #define poll_check_ok(pop) | |
| 116 #endif | |
| 117 | |
| 118 static int | |
| 119 poll_dispatch(struct event_base *base, struct timeval *tv) | |
| 120 { | |
| 121 int res, i, j, nfds; | |
| 122 long msec = -1; | |
| 123 struct pollop *pop = base->evbase; | |
| 124 struct pollfd *event_set; | |
| 125 | |
| 126 poll_check_ok(pop); | |
| 127 | |
| 128 nfds = pop->nfds; | |
| 129 | |
| 130 #ifndef _EVENT_DISABLE_THREAD_SUPPORT | |
| 131 if (base->th_base_lock) { | |
| 132 /* If we're using this backend in a multithreaded setting, | |
| 133 * then we need to work on a copy of event_set, so that we can | |
| 134 * let other threads modify the main event_set while we're | |
| 135 * polling. If we're not multithreaded, then we'll skip the | |
| 136 * copy step here to save memory and time. */ | |
| 137 if (pop->realloc_copy) { | |
| 138 struct pollfd *tmp = mm_realloc(pop->event_set_copy, | |
| 139 pop->event_count * sizeof(struct pollfd)); | |
| 140 if (tmp == NULL) { | |
| 141 event_warn("realloc"); | |
| 142 return -1; | |
| 143 } | |
| 144 pop->event_set_copy = tmp; | |
| 145 pop->realloc_copy = 0; | |
| 146 } | |
| 147 memcpy(pop->event_set_copy, pop->event_set, | |
| 148 sizeof(struct pollfd)*nfds); | |
| 149 event_set = pop->event_set_copy; | |
| 150 } else { | |
| 151 event_set = pop->event_set; | |
| 152 } | |
| 153 #else | |
| 154 event_set = pop->event_set; | |
| 155 #endif | |
| 156 | |
| 157 if (tv != NULL) { | |
| 158 msec = evutil_tv_to_msec(tv); | |
| 159 if (msec < 0 || msec > INT_MAX) | |
| 160 msec = INT_MAX; | |
| 161 } | |
| 162 | |
| 163 EVBASE_RELEASE_LOCK(base, th_base_lock); | |
| 164 | |
| 165 res = poll(event_set, nfds, msec); | |
| 166 | |
| 167 EVBASE_ACQUIRE_LOCK(base, th_base_lock); | |
| 168 | |
| 169 if (res == -1) { | |
| 170 if (errno != EINTR) { | |
| 171 event_warn("poll"); | |
| 172 return (-1); | |
| 173 } | |
| 174 | |
| 175 return (0); | |
| 176 } | |
| 177 | |
| 178 event_debug(("%s: poll reports %d", __func__, res)); | |
| 179 | |
| 180 if (res == 0 || nfds == 0) | |
| 181 return (0); | |
| 182 | |
| 183 i = random() % nfds; | |
| 184 for (j = 0; j < nfds; j++) { | |
| 185 int what; | |
| 186 if (++i == nfds) | |
| 187 i = 0; | |
| 188 what = event_set[i].revents; | |
| 189 if (!what) | |
| 190 continue; | |
| 191 | |
| 192 res = 0; | |
| 193 | |
| 194 /* If the file gets closed notify */ | |
| 195 if (what & (POLLHUP|POLLERR)) | |
| 196 what |= POLLIN|POLLOUT; | |
| 197 if (what & POLLIN) | |
| 198 res |= EV_READ; | |
| 199 if (what & POLLOUT) | |
| 200 res |= EV_WRITE; | |
| 201 if (res == 0) | |
| 202 continue; | |
| 203 | |
| 204 evmap_io_active(base, event_set[i].fd, res); | |
| 205 } | |
| 206 | |
| 207 return (0); | |
| 208 } | |
| 209 | |
| 210 static int | |
| 211 poll_add(struct event_base *base, int fd, short old, short events, void *_idx) | |
| 212 { | |
| 213 struct pollop *pop = base->evbase; | |
| 214 struct pollfd *pfd = NULL; | |
| 215 struct pollidx *idx = _idx; | |
| 216 int i; | |
| 217 | |
| 218 EVUTIL_ASSERT((events & EV_SIGNAL) == 0); | |
| 219 if (!(events & (EV_READ|EV_WRITE))) | |
| 220 return (0); | |
| 221 | |
| 222 poll_check_ok(pop); | |
| 223 if (pop->nfds + 1 >= pop->event_count) { | |
| 224 struct pollfd *tmp_event_set; | |
| 225 int tmp_event_count; | |
| 226 | |
| 227 if (pop->event_count < 32) | |
| 228 tmp_event_count = 32; | |
| 229 else | |
| 230 tmp_event_count = pop->event_count * 2; | |
| 231 | |
| 232 /* We need more file descriptors */ | |
| 233 tmp_event_set = mm_realloc(pop->event_set, | |
| 234 tmp_event_count * sizeof(struct pollfd)); | |
| 235 if (tmp_event_set == NULL) { | |
| 236 event_warn("realloc"); | |
| 237 return (-1); | |
| 238 } | |
| 239 pop->event_set = tmp_event_set; | |
| 240 | |
| 241 pop->event_count = tmp_event_count; | |
| 242 pop->realloc_copy = 1; | |
| 243 } | |
| 244 | |
| 245 i = idx->idxplus1 - 1; | |
| 246 | |
| 247 if (i >= 0) { | |
| 248 pfd = &pop->event_set[i]; | |
| 249 } else { | |
| 250 i = pop->nfds++; | |
| 251 pfd = &pop->event_set[i]; | |
| 252 pfd->events = 0; | |
| 253 pfd->fd = fd; | |
| 254 idx->idxplus1 = i + 1; | |
| 255 } | |
| 256 | |
| 257 pfd->revents = 0; | |
| 258 if (events & EV_WRITE) | |
| 259 pfd->events |= POLLOUT; | |
| 260 if (events & EV_READ) | |
| 261 pfd->events |= POLLIN; | |
| 262 poll_check_ok(pop); | |
| 263 | |
| 264 return (0); | |
| 265 } | |
| 266 | |
| 267 /* | |
| 268 * Nothing to be done here. | |
| 269 */ | |
| 270 | |
| 271 static int | |
| 272 poll_del(struct event_base *base, int fd, short old, short events, void *_idx) | |
| 273 { | |
| 274 struct pollop *pop = base->evbase; | |
| 275 struct pollfd *pfd = NULL; | |
| 276 struct pollidx *idx = _idx; | |
| 277 int i; | |
| 278 | |
| 279 EVUTIL_ASSERT((events & EV_SIGNAL) == 0); | |
| 280 if (!(events & (EV_READ|EV_WRITE))) | |
| 281 return (0); | |
| 282 | |
| 283 poll_check_ok(pop); | |
| 284 i = idx->idxplus1 - 1; | |
| 285 if (i < 0) | |
| 286 return (-1); | |
| 287 | |
| 288 /* Do we still want to read or write? */ | |
| 289 pfd = &pop->event_set[i]; | |
| 290 if (events & EV_READ) | |
| 291 pfd->events &= ~POLLIN; | |
| 292 if (events & EV_WRITE) | |
| 293 pfd->events &= ~POLLOUT; | |
| 294 poll_check_ok(pop); | |
| 295 if (pfd->events) | |
| 296 /* Another event cares about that fd. */ | |
| 297 return (0); | |
| 298 | |
| 299 /* Okay, so we aren't interested in that fd anymore. */ | |
| 300 idx->idxplus1 = 0; | |
| 301 | |
| 302 --pop->nfds; | |
| 303 if (i != pop->nfds) { | |
| 304 /* | |
| 305 * Shift the last pollfd down into the now-unoccupied | |
| 306 * position. | |
| 307 */ | |
| 308 memcpy(&pop->event_set[i], &pop->event_set[pop->nfds], | |
| 309 sizeof(struct pollfd)); | |
| 310 idx = evmap_io_get_fdinfo(&base->io, pop->event_set[i].fd); | |
| 311 EVUTIL_ASSERT(idx); | |
| 312 EVUTIL_ASSERT(idx->idxplus1 == pop->nfds + 1); | |
| 313 idx->idxplus1 = i + 1; | |
| 314 } | |
| 315 | |
| 316 poll_check_ok(pop); | |
| 317 return (0); | |
| 318 } | |
| 319 | |
| 320 static void | |
| 321 poll_dealloc(struct event_base *base) | |
| 322 { | |
| 323 struct pollop *pop = base->evbase; | |
| 324 | |
| 325 evsig_dealloc(base); | |
| 326 if (pop->event_set) | |
| 327 mm_free(pop->event_set); | |
| 328 if (pop->event_set_copy) | |
| 329 mm_free(pop->event_set_copy); | |
| 330 | |
| 331 memset(pop, 0, sizeof(struct pollop)); | |
| 332 mm_free(pop); | |
| 333 } |
