1 /* $OpenBSD: kqueue.c,v 1.5 2002/07/10 14:41:31 art 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 #include "evconfig-private.h" 31 32 #ifdef EVENT__HAVE_KQUEUE 33 34 #include <sys/types.h> 35 #ifdef EVENT__HAVE_SYS_TIME_H 36 #include <sys/time.h> 37 #endif 38 #include <sys/queue.h> 39 #include <sys/event.h> 40 #include <signal.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <unistd.h> 45 #include <errno.h> 46 #ifdef EVENT__HAVE_INTTYPES_H 47 #include <inttypes.h> 48 #endif 49 50 /* Some platforms apparently define the udata field of struct kevent as 51 * intptr_t, whereas others define it as void*. There doesn't seem to be an 52 * easy way to tell them apart via autoconf, so we need to use OS macros. */ 53 #if defined(EVENT__HAVE_INTTYPES_H) && !defined(__OpenBSD__) && !defined(__FreeBSD__) && !defined(__darwin__) && !defined(__APPLE__) && !defined(__CloudABI__) 54 #define PTR_TO_UDATA(x) ((intptr_t)(x)) 55 #define INT_TO_UDATA(x) ((intptr_t)(x)) 56 #else 57 #define PTR_TO_UDATA(x) (x) 58 #define INT_TO_UDATA(x) ((void*)(x)) 59 #endif 60 61 #include "event-internal.h" 62 #include "log-internal.h" 63 #include "evmap-internal.h" 64 #include "event2/thread.h" 65 #include "evthread-internal.h" 66 #include "changelist-internal.h" 67 68 #include "kqueue-internal.h" 69 70 #define NEVENT 64 71 72 struct kqop { 73 struct kevent *changes; 74 int changes_size; 75 76 struct kevent *events; 77 int events_size; 78 int kq; 79 int notify_event_added; 80 pid_t pid; 81 }; 82 83 static void kqop_free(struct kqop *kqop); 84 85 static void *kq_init(struct event_base *); 86 static int kq_sig_add(struct event_base *, int, short, short, void *); 87 static int kq_sig_del(struct event_base *, int, short, short, void *); 88 static int kq_dispatch(struct event_base *, struct timeval *); 89 static void kq_dealloc(struct event_base *); 90 91 const struct eventop kqops = { 92 "kqueue", 93 kq_init, 94 event_changelist_add_, 95 event_changelist_del_, 96 kq_dispatch, 97 kq_dealloc, 98 1 /* need reinit */, 99 EV_FEATURE_ET|EV_FEATURE_O1|EV_FEATURE_FDS, 100 EVENT_CHANGELIST_FDINFO_SIZE 101 }; 102 103 static const struct eventop kqsigops = { 104 "kqueue_signal", 105 NULL, 106 kq_sig_add, 107 kq_sig_del, 108 NULL, 109 NULL, 110 1 /* need reinit */, 111 0, 112 0 113 }; 114 115 static void * 116 kq_init(struct event_base *base) 117 { 118 int kq = -1; 119 struct kqop *kqueueop = NULL; 120 121 if (!(kqueueop = mm_calloc(1, sizeof(struct kqop)))) 122 return (NULL); 123 124 /* Initialize the kernel queue */ 125 126 if ((kq = kqueue()) == -1) { 127 event_warn("kqueue"); 128 goto err; 129 } 130 131 kqueueop->kq = kq; 132 133 kqueueop->pid = getpid(); 134 135 /* Initialize fields */ 136 kqueueop->changes = mm_calloc(NEVENT, sizeof(struct kevent)); 137 if (kqueueop->changes == NULL) 138 goto err; 139 kqueueop->events = mm_calloc(NEVENT, sizeof(struct kevent)); 140 if (kqueueop->events == NULL) 141 goto err; 142 kqueueop->events_size = kqueueop->changes_size = NEVENT; 143 144 /* Check for Mac OS X kqueue bug. */ 145 memset(&kqueueop->changes[0], 0, sizeof kqueueop->changes[0]); 146 kqueueop->changes[0].ident = -1; 147 kqueueop->changes[0].filter = EVFILT_READ; 148 kqueueop->changes[0].flags = EV_ADD; 149 /* 150 * If kqueue works, then kevent will succeed, and it will 151 * stick an error in events[0]. If kqueue is broken, then 152 * kevent will fail. 153 */ 154 if (kevent(kq, 155 kqueueop->changes, 1, kqueueop->events, NEVENT, NULL) != 1 || 156 (int)kqueueop->events[0].ident != -1 || 157 !(kqueueop->events[0].flags & EV_ERROR)) { 158 event_warn("%s: detected broken kqueue; not using.", __func__); 159 goto err; 160 } 161 162 base->evsigsel = &kqsigops; 163 164 return (kqueueop); 165 err: 166 if (kqueueop) 167 kqop_free(kqueueop); 168 169 return (NULL); 170 } 171 172 #define ADD_UDATA 0x30303 173 174 static void 175 kq_setup_kevent(struct kevent *out, evutil_socket_t fd, int filter, short change) 176 { 177 memset(out, 0, sizeof(struct kevent)); 178 out->ident = fd; 179 out->filter = filter; 180 181 if (change & EV_CHANGE_ADD) { 182 out->flags = EV_ADD; 183 /* We set a magic number here so that we can tell 'add' 184 * errors from 'del' errors. */ 185 out->udata = INT_TO_UDATA(ADD_UDATA); 186 if (change & EV_ET) 187 out->flags |= EV_CLEAR; 188 #ifdef NOTE_EOF 189 /* Make it behave like select() and poll() */ 190 if (filter == EVFILT_READ) 191 out->fflags = NOTE_EOF; 192 #endif 193 } else { 194 EVUTIL_ASSERT(change & EV_CHANGE_DEL); 195 out->flags = EV_DELETE; 196 } 197 } 198 199 static int 200 kq_build_changes_list(const struct event_changelist *changelist, 201 struct kqop *kqop) 202 { 203 int i; 204 int n_changes = 0; 205 206 for (i = 0; i < changelist->n_changes; ++i) { 207 struct event_change *in_ch = &changelist->changes[i]; 208 struct kevent *out_ch; 209 if (n_changes >= kqop->changes_size - 1) { 210 int newsize = kqop->changes_size * 2; 211 struct kevent *newchanges; 212 213 newchanges = mm_realloc(kqop->changes, 214 newsize * sizeof(struct kevent)); 215 if (newchanges == NULL) { 216 event_warn("%s: realloc", __func__); 217 return (-1); 218 } 219 kqop->changes = newchanges; 220 kqop->changes_size = newsize; 221 } 222 if (in_ch->read_change) { 223 out_ch = &kqop->changes[n_changes++]; 224 kq_setup_kevent(out_ch, in_ch->fd, EVFILT_READ, 225 in_ch->read_change); 226 } 227 if (in_ch->write_change) { 228 out_ch = &kqop->changes[n_changes++]; 229 kq_setup_kevent(out_ch, in_ch->fd, EVFILT_WRITE, 230 in_ch->write_change); 231 } 232 } 233 return n_changes; 234 } 235 236 static int 237 kq_grow_events(struct kqop *kqop, size_t new_size) 238 { 239 struct kevent *newresult; 240 241 newresult = mm_realloc(kqop->events, 242 new_size * sizeof(struct kevent)); 243 244 if (newresult) { 245 kqop->events = newresult; 246 kqop->events_size = new_size; 247 return 0; 248 } else { 249 return -1; 250 } 251 } 252 253 static int 254 kq_dispatch(struct event_base *base, struct timeval *tv) 255 { 256 struct kqop *kqop = base->evbase; 257 struct kevent *events = kqop->events; 258 struct kevent *changes; 259 struct timespec ts, *ts_p = NULL; 260 int i, n_changes, res; 261 262 if (tv != NULL) { 263 ts.tv_sec = tv->tv_sec; 264 ts.tv_nsec = tv->tv_usec * 1000; 265 ts_p = &ts; 266 } 267 268 /* Build "changes" from "base->changes" */ 269 EVUTIL_ASSERT(kqop->changes); 270 n_changes = kq_build_changes_list(&base->changelist, kqop); 271 if (n_changes < 0) 272 return -1; 273 274 event_changelist_remove_all_(&base->changelist, base); 275 276 /* steal the changes array in case some broken code tries to call 277 * dispatch twice at once. */ 278 changes = kqop->changes; 279 kqop->changes = NULL; 280 281 /* Make sure that 'events' is at least as long as the list of changes: 282 * otherwise errors in the changes can get reported as a -1 return 283 * value from kevent() rather than as EV_ERROR events in the events 284 * array. 285 * 286 * (We could instead handle -1 return values from kevent() by 287 * retrying with a smaller changes array or a larger events array, 288 * but this approach seems less risky for now.) 289 */ 290 if (kqop->events_size < n_changes) { 291 int new_size = kqop->events_size; 292 do { 293 new_size *= 2; 294 } while (new_size < n_changes); 295 296 kq_grow_events(kqop, new_size); 297 events = kqop->events; 298 } 299 300 EVBASE_RELEASE_LOCK(base, th_base_lock); 301 302 res = kevent(kqop->kq, changes, n_changes, 303 events, kqop->events_size, ts_p); 304 305 EVBASE_ACQUIRE_LOCK(base, th_base_lock); 306 307 EVUTIL_ASSERT(kqop->changes == NULL); 308 kqop->changes = changes; 309 310 if (res == -1) { 311 if (errno != EINTR) { 312 event_warn("kevent"); 313 return (-1); 314 } 315 316 return (0); 317 } 318 319 event_debug(("%s: kevent reports %d", __func__, res)); 320 321 for (i = 0; i < res; i++) { 322 int which = 0; 323 324 if (events[i].flags & EV_ERROR) { 325 switch (events[i].data) { 326 327 /* Can occur on delete if we are not currently 328 * watching any events on this fd. That can 329 * happen when the fd was closed and another 330 * file was opened with that fd. */ 331 case ENOENT: 332 /* Can occur for reasons not fully understood 333 * on FreeBSD. */ 334 case EINVAL: 335 continue; 336 #if defined(__FreeBSD__) 337 /* 338 * This currently occurs if an FD is closed 339 * before the EV_DELETE makes it out via kevent(). 340 * The FreeBSD capabilities code sees the blank 341 * capability set and rejects the request to 342 * modify an event. 343 * 344 * To be strictly correct - when an FD is closed, 345 * all the registered events are also removed. 346 * Queuing EV_DELETE to a closed FD is wrong. 347 * The event(s) should just be deleted from 348 * the pending changelist. 349 */ 350 case ENOTCAPABLE: 351 continue; 352 #endif 353 354 /* Can occur on a delete if the fd is closed. */ 355 case EBADF: 356 /* XXXX On NetBSD, we can also get EBADF if we 357 * try to add the write side of a pipe, but 358 * the read side has already been closed. 359 * Other BSDs call this situation 'EPIPE'. It 360 * would be good if we had a way to report 361 * this situation. */ 362 continue; 363 /* These two can occur on an add if the fd was one side 364 * of a pipe, and the other side was closed. */ 365 case EPERM: 366 case EPIPE: 367 /* Report read events, if we're listening for 368 * them, so that the user can learn about any 369 * add errors. (If the operation was a 370 * delete, then udata should be cleared.) */ 371 if (events[i].udata) { 372 /* The operation was an add: 373 * report the error as a read. */ 374 which |= EV_READ; 375 break; 376 } else { 377 /* The operation was a del: 378 * report nothing. */ 379 continue; 380 } 381 382 /* Other errors shouldn't occur. */ 383 default: 384 errno = events[i].data; 385 return (-1); 386 } 387 } else if (events[i].filter == EVFILT_READ) { 388 which |= EV_READ; 389 } else if (events[i].filter == EVFILT_WRITE) { 390 which |= EV_WRITE; 391 } else if (events[i].filter == EVFILT_SIGNAL) { 392 which |= EV_SIGNAL; 393 #ifdef EVFILT_USER 394 } else if (events[i].filter == EVFILT_USER) { 395 base->is_notify_pending = 0; 396 #endif 397 } 398 399 if (!which) 400 continue; 401 402 if (events[i].filter == EVFILT_SIGNAL) { 403 evmap_signal_active_(base, events[i].ident, 1); 404 } else { 405 evmap_io_active_(base, events[i].ident, which | EV_ET); 406 } 407 } 408 409 if (res == kqop->events_size) { 410 /* We used all the events space that we have. Maybe we should 411 make it bigger. */ 412 kq_grow_events(kqop, kqop->events_size * 2); 413 } 414 415 return (0); 416 } 417 418 static void 419 kqop_free(struct kqop *kqop) 420 { 421 if (kqop->changes) 422 mm_free(kqop->changes); 423 if (kqop->events) 424 mm_free(kqop->events); 425 if (kqop->kq >= 0 && kqop->pid == getpid()) 426 close(kqop->kq); 427 memset(kqop, 0, sizeof(struct kqop)); 428 mm_free(kqop); 429 } 430 431 static void 432 kq_dealloc(struct event_base *base) 433 { 434 struct kqop *kqop = base->evbase; 435 evsig_dealloc_(base); 436 kqop_free(kqop); 437 } 438 439 /* signal handling */ 440 static int 441 kq_sig_add(struct event_base *base, int nsignal, short old, short events, void *p) 442 { 443 struct kqop *kqop = base->evbase; 444 struct kevent kev; 445 struct timespec timeout = { 0, 0 }; 446 (void)p; 447 448 EVUTIL_ASSERT(nsignal >= 0 && nsignal < NSIG); 449 450 memset(&kev, 0, sizeof(kev)); 451 kev.ident = nsignal; 452 kev.filter = EVFILT_SIGNAL; 453 kev.flags = EV_ADD; 454 455 /* Be ready for the signal if it is sent any 456 * time between now and the next call to 457 * kq_dispatch. */ 458 if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1) 459 return (-1); 460 461 /* We can set the handler for most signals to SIG_IGN and 462 * still have them reported to us in the queue. However, 463 * if the handler for SIGCHLD is SIG_IGN, the system reaps 464 * zombie processes for us, and we don't get any notification. 465 * This appears to be the only signal with this quirk. */ 466 if (evsig_set_handler_(base, nsignal, 467 nsignal == SIGCHLD ? SIG_DFL : SIG_IGN) == -1) 468 return (-1); 469 470 return (0); 471 } 472 473 static int 474 kq_sig_del(struct event_base *base, int nsignal, short old, short events, void *p) 475 { 476 struct kqop *kqop = base->evbase; 477 struct kevent kev; 478 479 struct timespec timeout = { 0, 0 }; 480 (void)p; 481 482 EVUTIL_ASSERT(nsignal >= 0 && nsignal < NSIG); 483 484 memset(&kev, 0, sizeof(kev)); 485 kev.ident = nsignal; 486 kev.filter = EVFILT_SIGNAL; 487 kev.flags = EV_DELETE; 488 489 /* Because we insert signal events 490 * immediately, we need to delete them 491 * immediately, too */ 492 if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1) 493 return (-1); 494 495 if (evsig_restore_handler_(base, nsignal) == -1) 496 return (-1); 497 498 return (0); 499 } 500 501 502 /* OSX 10.6 and FreeBSD 8.1 add support for EVFILT_USER, which we can use 503 * to wake up the event loop from another thread. */ 504 505 /* Magic number we use for our filter ID. */ 506 #define NOTIFY_IDENT 42 507 508 int 509 event_kq_add_notify_event_(struct event_base *base) 510 { 511 struct kqop *kqop = base->evbase; 512 #if defined(EVFILT_USER) && defined(NOTE_TRIGGER) 513 struct kevent kev; 514 struct timespec timeout = { 0, 0 }; 515 #endif 516 517 if (kqop->notify_event_added) 518 return 0; 519 520 #if defined(EVFILT_USER) && defined(NOTE_TRIGGER) 521 memset(&kev, 0, sizeof(kev)); 522 kev.ident = NOTIFY_IDENT; 523 kev.filter = EVFILT_USER; 524 kev.flags = EV_ADD | EV_CLEAR; 525 526 if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1) { 527 event_warn("kevent: adding EVFILT_USER event"); 528 return -1; 529 } 530 531 kqop->notify_event_added = 1; 532 533 return 0; 534 #else 535 return -1; 536 #endif 537 } 538 539 int 540 event_kq_notify_base_(struct event_base *base) 541 { 542 struct kqop *kqop = base->evbase; 543 #if defined(EVFILT_USER) && defined(NOTE_TRIGGER) 544 struct kevent kev; 545 struct timespec timeout = { 0, 0 }; 546 #endif 547 if (! kqop->notify_event_added) 548 return -1; 549 550 #if defined(EVFILT_USER) && defined(NOTE_TRIGGER) 551 memset(&kev, 0, sizeof(kev)); 552 kev.ident = NOTIFY_IDENT; 553 kev.filter = EVFILT_USER; 554 kev.fflags = NOTE_TRIGGER; 555 556 if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1) { 557 event_warn("kevent: triggering EVFILT_USER event"); 558 return -1; 559 } 560 561 return 0; 562 #else 563 return -1; 564 #endif 565 } 566 567 #endif /* EVENT__HAVE_KQUEUE */ 568