1 /* $OpenBSD: kqueue.c,v 1.5 2002/07/10 14:41:31 art Exp $ */ 2 3 /* 4 * Copyright 2000-2007 Niels Provos <provos (at) 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 #define _GNU_SOURCE 32 33 #include <sys/types.h> 34 #ifdef _EVENT_HAVE_SYS_TIME_H 35 #include <sys/time.h> 36 #endif 37 #include <sys/queue.h> 38 #include <sys/event.h> 39 #include <signal.h> 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <unistd.h> 44 #include <errno.h> 45 #ifdef _EVENT_HAVE_INTTYPES_H 46 #include <inttypes.h> 47 #endif 48 49 /* Some platforms apparently define the udata field of struct kevent as 50 * intptr_t, whereas others define it as void*. There doesn't seem to be an 51 * easy way to tell them apart via autoconf, so we need to use OS macros. */ 52 #if defined(_EVENT_HAVE_INTTYPES_H) && !defined(__OpenBSD__) && !defined(__FreeBSD__) && !defined(__darwin__) && !defined(__APPLE__) 53 #define PTR_TO_UDATA(x) ((intptr_t)(x)) 54 #define INT_TO_UDATA(x) ((intptr_t)(x)) 55 #else 56 #define PTR_TO_UDATA(x) (x) 57 #define INT_TO_UDATA(x) ((void*)(x)) 58 #endif 59 60 #include "event-internal.h" 61 #include "log-internal.h" 62 #include "evmap-internal.h" 63 #include "event2/thread.h" 64 #include "evthread-internal.h" 65 #include "changelist-internal.h" 66 67 #define NEVENT 64 68 69 struct kqop { 70 struct kevent *changes; 71 int changes_size; 72 73 struct kevent *events; 74 int events_size; 75 int kq; 76 pid_t pid; 77 }; 78 79 static void kqop_free(struct kqop *kqop); 80 81 static void *kq_init(struct event_base *); 82 static int kq_sig_add(struct event_base *, int, short, short, void *); 83 static int kq_sig_del(struct event_base *, int, short, short, void *); 84 static int kq_dispatch(struct event_base *, struct timeval *); 85 static void kq_dealloc(struct event_base *); 86 87 const struct eventop kqops = { 88 "kqueue", 89 kq_init, 90 event_changelist_add, 91 event_changelist_del, 92 kq_dispatch, 93 kq_dealloc, 94 1 /* need reinit */, 95 EV_FEATURE_ET|EV_FEATURE_O1|EV_FEATURE_FDS, 96 EVENT_CHANGELIST_FDINFO_SIZE 97 }; 98 99 static const struct eventop kqsigops = { 100 "kqueue_signal", 101 NULL, 102 kq_sig_add, 103 kq_sig_del, 104 NULL, 105 NULL, 106 1 /* need reinit */, 107 0, 108 0 109 }; 110 111 static void * 112 kq_init(struct event_base *base) 113 { 114 int kq = -1; 115 struct kqop *kqueueop = NULL; 116 117 if (!(kqueueop = mm_calloc(1, sizeof(struct kqop)))) 118 return (NULL); 119 120 /* Initialize the kernel queue */ 121 122 if ((kq = kqueue()) == -1) { 123 event_warn("kqueue"); 124 goto err; 125 } 126 127 kqueueop->kq = kq; 128 129 kqueueop->pid = getpid(); 130 131 /* Initialize fields */ 132 kqueueop->changes = mm_calloc(NEVENT, sizeof(struct kevent)); 133 if (kqueueop->changes == NULL) 134 goto err; 135 kqueueop->events = mm_calloc(NEVENT, sizeof(struct kevent)); 136 if (kqueueop->events == NULL) 137 goto err; 138 kqueueop->events_size = kqueueop->changes_size = NEVENT; 139 140 /* Check for Mac OS X kqueue bug. */ 141 memset(&kqueueop->changes[0], 0, sizeof kqueueop->changes[0]); 142 kqueueop->changes[0].ident = -1; 143 kqueueop->changes[0].filter = EVFILT_READ; 144 kqueueop->changes[0].flags = EV_ADD; 145 /* 146 * If kqueue works, then kevent will succeed, and it will 147 * stick an error in events[0]. If kqueue is broken, then 148 * kevent will fail. 149 */ 150 if (kevent(kq, 151 kqueueop->changes, 1, kqueueop->events, NEVENT, NULL) != 1 || 152 (int)kqueueop->events[0].ident != -1 || 153 kqueueop->events[0].flags != EV_ERROR) { 154 event_warn("%s: detected broken kqueue; not using.", __func__); 155 goto err; 156 } 157 158 base->evsigsel = &kqsigops; 159 160 return (kqueueop); 161 err: 162 if (kqueueop) 163 kqop_free(kqueueop); 164 165 return (NULL); 166 } 167 168 static void 169 kq_sighandler(int sig) 170 { 171 /* Do nothing here */ 172 } 173 174 #define ADD_UDATA 0x30303 175 176 static void 177 kq_setup_kevent(struct kevent *out, evutil_socket_t fd, int filter, short change) 178 { 179 memset(out, 0, sizeof(struct kevent)); 180 out->ident = fd; 181 out->filter = filter; 182 183 if (change & EV_CHANGE_ADD) { 184 out->flags = EV_ADD; 185 /* We set a magic number here so that we can tell 'add' 186 * errors from 'del' errors. */ 187 out->udata = INT_TO_UDATA(ADD_UDATA); 188 if (change & EV_ET) 189 out->flags |= EV_CLEAR; 190 #ifdef NOTE_EOF 191 /* Make it behave like select() and poll() */ 192 if (filter == EVFILT_READ) 193 out->fflags = NOTE_EOF; 194 #endif 195 } else { 196 EVUTIL_ASSERT(change & EV_CHANGE_DEL); 197 out->flags = EV_DELETE; 198 } 199 } 200 201 static int 202 kq_build_changes_list(const struct event_changelist *changelist, 203 struct kqop *kqop) 204 { 205 int i; 206 int n_changes = 0; 207 208 for (i = 0; i < changelist->n_changes; ++i) { 209 struct event_change *in_ch = &changelist->changes[i]; 210 struct kevent *out_ch; 211 if (n_changes >= kqop->changes_size - 1) { 212 int newsize = kqop->changes_size * 2; 213 struct kevent *newchanges; 214 215 newchanges = mm_realloc(kqop->changes, 216 newsize * sizeof(struct kevent)); 217 if (newchanges == NULL) { 218 event_warn("%s: realloc", __func__); 219 return (-1); 220 } 221 kqop->changes = newchanges; 222 kqop->changes_size = newsize; 223 } 224 if (in_ch->read_change) { 225 out_ch = &kqop->changes[n_changes++]; 226 kq_setup_kevent(out_ch, in_ch->fd, EVFILT_READ, 227 in_ch->read_change); 228 } 229 if (in_ch->write_change) { 230 out_ch = &kqop->changes[n_changes++]; 231 kq_setup_kevent(out_ch, in_ch->fd, EVFILT_WRITE, 232 in_ch->write_change); 233 } 234 } 235 return n_changes; 236 } 237 238 static int 239 kq_grow_events(struct kqop *kqop, size_t new_size) 240 { 241 struct kevent *newresult; 242 243 newresult = mm_realloc(kqop->events, 244 new_size * sizeof(struct kevent)); 245 246 if (newresult) { 247 kqop->events = newresult; 248 kqop->events_size = new_size; 249 return 0; 250 } else { 251 return -1; 252 } 253 } 254 255 static int 256 kq_dispatch(struct event_base *base, struct timeval *tv) 257 { 258 struct kqop *kqop = base->evbase; 259 struct kevent *events = kqop->events; 260 struct kevent *changes; 261 struct timespec ts, *ts_p = NULL; 262 int i, n_changes, res; 263 264 if (tv != NULL) { 265 TIMEVAL_TO_TIMESPEC(tv, &ts); 266 ts_p = &ts; 267 } 268 269 /* Build "changes" from "base->changes" */ 270 EVUTIL_ASSERT(kqop->changes); 271 n_changes = kq_build_changes_list(&base->changelist, kqop); 272 if (n_changes < 0) 273 return -1; 274 275 event_changelist_remove_all(&base->changelist, base); 276 277 /* steal the changes array in case some broken code tries to call 278 * dispatch twice at once. */ 279 changes = kqop->changes; 280 kqop->changes = NULL; 281 282 /* Make sure that 'events' is at least as long as the list of changes: 283 * otherwise errors in the changes can get reported as a -1 return 284 * value from kevent() rather than as EV_ERROR events in the events 285 * array. 286 * 287 * (We could instead handle -1 return values from kevent() by 288 * retrying with a smaller changes array or a larger events array, 289 * but this approach seems less risky for now.) 290 */ 291 if (kqop->events_size < n_changes) { 292 int new_size = kqop->events_size; 293 do { 294 new_size *= 2; 295 } while (new_size < n_changes); 296 297 kq_grow_events(kqop, new_size); 298 events = kqop->events; 299 } 300 301 EVBASE_RELEASE_LOCK(base, th_base_lock); 302 303 res = kevent(kqop->kq, changes, n_changes, 304 events, kqop->events_size, ts_p); 305 306 EVBASE_ACQUIRE_LOCK(base, th_base_lock); 307 308 EVUTIL_ASSERT(kqop->changes == NULL); 309 kqop->changes = changes; 310 311 if (res == -1) { 312 if (errno != EINTR) { 313 event_warn("kevent"); 314 return (-1); 315 } 316 317 return (0); 318 } 319 320 event_debug(("%s: kevent reports %d", __func__, res)); 321 322 for (i = 0; i < res; i++) { 323 int which = 0; 324 325 if (events[i].flags & EV_ERROR) { 326 switch (events[i].data) { 327 328 /* Can occur on delete if we are not currently 329 * watching any events on this fd. That can 330 * happen when the fd was closed and another 331 * file was opened with that fd. */ 332 case ENOENT: 333 /* Can occur for reasons not fully understood 334 * on FreeBSD. */ 335 case EINVAL: 336 continue; 337 338 /* Can occur on a delete if the fd is closed. */ 339 case EBADF: 340 /* XXXX On NetBSD, we can also get EBADF if we 341 * try to add the write side of a pipe, but 342 * the read side has already been closed. 343 * Other BSDs call this situation 'EPIPE'. It 344 * would be good if we had a way to report 345 * this situation. */ 346 continue; 347 /* These two can occur on an add if the fd was one side 348 * of a pipe, and the other side was closed. */ 349 case EPERM: 350 case EPIPE: 351 /* Report read events, if we're listening for 352 * them, so that the user can learn about any 353 * add errors. (If the operation was a 354 * delete, then udata should be cleared.) */ 355 if (events[i].udata) { 356 /* The operation was an add: 357 * report the error as a read. */ 358 which |= EV_READ; 359 break; 360 } else { 361 /* The operation was a del: 362 * report nothing. */ 363 continue; 364 } 365 366 /* Other errors shouldn't occur. */ 367 default: 368 errno = events[i].data; 369 return (-1); 370 } 371 } else if (events[i].filter == EVFILT_READ) { 372 which |= EV_READ; 373 } else if (events[i].filter == EVFILT_WRITE) { 374 which |= EV_WRITE; 375 } else if (events[i].filter == EVFILT_SIGNAL) { 376 which |= EV_SIGNAL; 377 } 378 379 if (!which) 380 continue; 381 382 if (events[i].filter == EVFILT_SIGNAL) { 383 evmap_signal_active(base, events[i].ident, 1); 384 } else { 385 evmap_io_active(base, events[i].ident, which | EV_ET); 386 } 387 } 388 389 if (res == kqop->events_size) { 390 /* We used all the events space that we have. Maybe we should 391 make it bigger. */ 392 kq_grow_events(kqop, kqop->events_size * 2); 393 } 394 395 return (0); 396 } 397 398 static void 399 kqop_free(struct kqop *kqop) 400 { 401 if (kqop->changes) 402 mm_free(kqop->changes); 403 if (kqop->events) 404 mm_free(kqop->events); 405 if (kqop->kq >= 0 && kqop->pid == getpid()) 406 close(kqop->kq); 407 memset(kqop, 0, sizeof(struct kqop)); 408 mm_free(kqop); 409 } 410 411 static void 412 kq_dealloc(struct event_base *base) 413 { 414 struct kqop *kqop = base->evbase; 415 evsig_dealloc(base); 416 kqop_free(kqop); 417 } 418 419 /* signal handling */ 420 static int 421 kq_sig_add(struct event_base *base, int nsignal, short old, short events, void *p) 422 { 423 struct kqop *kqop = base->evbase; 424 struct kevent kev; 425 struct timespec timeout = { 0, 0 }; 426 (void)p; 427 428 EVUTIL_ASSERT(nsignal >= 0 && nsignal < NSIG); 429 430 memset(&kev, 0, sizeof(kev)); 431 kev.ident = nsignal; 432 kev.filter = EVFILT_SIGNAL; 433 kev.flags = EV_ADD; 434 435 /* Be ready for the signal if it is sent any 436 * time between now and the next call to 437 * kq_dispatch. */ 438 if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1) 439 return (-1); 440 441 /* XXXX The manpage suggest we could use SIG_IGN instead of a 442 * do-nothing handler */ 443 if (_evsig_set_handler(base, nsignal, kq_sighandler) == -1) 444 return (-1); 445 446 return (0); 447 } 448 449 static int 450 kq_sig_del(struct event_base *base, int nsignal, short old, short events, void *p) 451 { 452 struct kqop *kqop = base->evbase; 453 struct kevent kev; 454 455 struct timespec timeout = { 0, 0 }; 456 (void)p; 457 458 EVUTIL_ASSERT(nsignal >= 0 && nsignal < NSIG); 459 460 memset(&kev, 0, sizeof(kev)); 461 kev.ident = nsignal; 462 kev.filter = EVFILT_SIGNAL; 463 kev.flags = EV_DELETE; 464 465 /* Because we insert signal events 466 * immediately, we need to delete them 467 * immediately, too */ 468 if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1) 469 return (-1); 470 471 if (_evsig_restore_handler(base, nsignal) == -1) 472 return (-1); 473 474 return (0); 475 } 476
