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 <limits.h>
41 #include <signal.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 #include <errno.h>
47 #ifdef EVENT__HAVE_INTTYPES_H
48 #include <inttypes.h>
49 #endif
50
51 /* Some platforms apparently define the udata field of struct kevent as
52 * intptr_t, whereas others define it as void*. There doesn't seem to be an
53 * easy way to tell them apart via autoconf, so we need to use OS macros. */
54 #if defined(__NetBSD__)
55 #define PTR_TO_UDATA(x) ((typeof(((struct kevent *)0)->udata))(x))
56 #define INT_TO_UDATA(x) ((typeof(((struct kevent *)0)->udata))(intptr_t)(x))
57 #elif defined(EVENT__HAVE_INTTYPES_H) && !defined(__OpenBSD__) && !defined(__FreeBSD__) && !defined(__darwin__) && !defined(__APPLE__) && !defined(__CloudABI__)
58 #define PTR_TO_UDATA(x) ((intptr_t)(x))
59 #define INT_TO_UDATA(x) ((intptr_t)(x))
60 #else
61 #define PTR_TO_UDATA(x) (x)
62 #define INT_TO_UDATA(x) ((void*)(x))
63 #endif
64
65 #include "event-internal.h"
66 #include "log-internal.h"
67 #include "evmap-internal.h"
68 #include "event2/thread.h"
69 #include "event2/util.h"
70 #include "evthread-internal.h"
71 #include "changelist-internal.h"
72
73 #include "kqueue-internal.h"
74
75 #define NEVENT 64
76
77 struct kqop {
78 struct kevent *changes;
79 int changes_size;
80
81 struct kevent *events;
82 int events_size;
83 int kq;
84 int notify_event_added;
85 pid_t pid;
86 };
87
88 static void kqop_free(struct kqop *kqop);
89
90 static void *kq_init(struct event_base *);
91 static int kq_sig_add(struct event_base *, int, short, short, void *);
92 static int kq_sig_del(struct event_base *, int, short, short, void *);
93 static int kq_dispatch(struct event_base *, struct timeval *);
94 static void kq_dealloc(struct event_base *);
95
96 const struct eventop kqops = {
97 "kqueue",
98 kq_init,
99 event_changelist_add_,
100 event_changelist_del_,
101 kq_dispatch,
102 kq_dealloc,
103 1 /* need reinit */,
104 EV_FEATURE_ET|EV_FEATURE_O1|EV_FEATURE_FDS,
105 EVENT_CHANGELIST_FDINFO_SIZE
106 };
107
108 static const struct eventop kqsigops = {
109 "kqueue_signal",
110 NULL,
111 kq_sig_add,
112 kq_sig_del,
113 NULL,
114 NULL,
115 1 /* need reinit */,
116 0,
117 0
118 };
119
120 static void *
kq_init(struct event_base * base)121 kq_init(struct event_base *base)
122 {
123 int kq = -1;
124 struct kqop *kqueueop = NULL;
125
126 if (!(kqueueop = mm_calloc(1, sizeof(struct kqop))))
127 return (NULL);
128
129 /* Initialize the kernel queue */
130
131 if ((kq = kqueue()) == -1) {
132 event_warn("kqueue");
133 goto err;
134 }
135
136 kqueueop->kq = kq;
137
138 kqueueop->pid = getpid();
139
140 /* Initialize fields */
141 kqueueop->changes = mm_calloc(NEVENT, sizeof(struct kevent));
142 if (kqueueop->changes == NULL)
143 goto err;
144 kqueueop->events = mm_calloc(NEVENT, sizeof(struct kevent));
145 if (kqueueop->events == NULL)
146 goto err;
147 kqueueop->events_size = kqueueop->changes_size = NEVENT;
148
149 /* Check for Mac OS X kqueue bug. */
150 memset(&kqueueop->changes[0], 0, sizeof kqueueop->changes[0]);
151 kqueueop->changes[0].ident = -1;
152 kqueueop->changes[0].filter = EVFILT_READ;
153 kqueueop->changes[0].flags = EV_ADD;
154 /*
155 * If kqueue works, then kevent will succeed, and it will
156 * stick an error in events[0]. If kqueue is broken, then
157 * kevent will fail.
158 */
159 if (kevent(kq,
160 kqueueop->changes, 1, kqueueop->events, NEVENT, NULL) != 1 ||
161 (int)kqueueop->events[0].ident != -1 ||
162 !(kqueueop->events[0].flags & EV_ERROR)) {
163 event_warn("%s: detected broken kqueue; not using.", __func__);
164 goto err;
165 }
166
167 base->evsigsel = &kqsigops;
168
169 return (kqueueop);
170 err:
171 if (kqueueop)
172 kqop_free(kqueueop);
173
174 return (NULL);
175 }
176
177 #define ADD_UDATA 0x30303
178
179 static void
kq_setup_kevent(struct kevent * out,evutil_socket_t fd,int filter,short change)180 kq_setup_kevent(struct kevent *out, evutil_socket_t fd, int filter, short change)
181 {
182 memset(out, 0, sizeof(struct kevent));
183 out->ident = fd;
184 out->filter = filter;
185
186 if (change & EV_CHANGE_ADD) {
187 out->flags = EV_ADD;
188 /* We set a magic number here so that we can tell 'add'
189 * errors from 'del' errors. */
190 out->udata = INT_TO_UDATA(ADD_UDATA);
191 if (change & EV_ET)
192 out->flags |= EV_CLEAR;
193 #ifdef NOTE_EOF
194 /* Make it behave like select() and poll() */
195 if (filter == EVFILT_READ)
196 out->fflags = NOTE_EOF;
197 #endif
198 } else {
199 EVUTIL_ASSERT(change & EV_CHANGE_DEL);
200 out->flags = EV_DELETE;
201 }
202 }
203
204 static int
kq_build_changes_list(const struct event_changelist * changelist,struct kqop * kqop)205 kq_build_changes_list(const struct event_changelist *changelist,
206 struct kqop *kqop)
207 {
208 int i;
209 int n_changes = 0;
210
211 for (i = 0; i < changelist->n_changes; ++i) {
212 struct event_change *in_ch = &changelist->changes[i];
213 struct kevent *out_ch;
214 if (n_changes >= kqop->changes_size - 1) {
215 int newsize;
216 struct kevent *newchanges;
217
218 if (kqop->changes_size > INT_MAX / 2 ||
219 (size_t)kqop->changes_size * 2 > EV_SIZE_MAX /
220 sizeof(struct kevent)) {
221 event_warnx("%s: int overflow", __func__);
222 return (-1);
223 }
224
225 newsize = kqop->changes_size * 2;
226 newchanges = mm_realloc(kqop->changes,
227 newsize * sizeof(struct kevent));
228 if (newchanges == NULL) {
229 event_warn("%s: realloc", __func__);
230 return (-1);
231 }
232 kqop->changes = newchanges;
233 kqop->changes_size = newsize;
234 }
235 if (in_ch->read_change) {
236 out_ch = &kqop->changes[n_changes++];
237 kq_setup_kevent(out_ch, in_ch->fd, EVFILT_READ,
238 in_ch->read_change);
239 }
240 if (in_ch->write_change) {
241 out_ch = &kqop->changes[n_changes++];
242 kq_setup_kevent(out_ch, in_ch->fd, EVFILT_WRITE,
243 in_ch->write_change);
244 }
245 }
246 return n_changes;
247 }
248
249 static int
kq_grow_events(struct kqop * kqop,size_t new_size)250 kq_grow_events(struct kqop *kqop, size_t new_size)
251 {
252 struct kevent *newresult;
253
254 newresult = mm_realloc(kqop->events,
255 new_size * sizeof(struct kevent));
256
257 if (newresult) {
258 kqop->events = newresult;
259 kqop->events_size = new_size;
260 return 0;
261 } else {
262 return -1;
263 }
264 }
265
266 static int
kq_dispatch(struct event_base * base,struct timeval * tv)267 kq_dispatch(struct event_base *base, struct timeval *tv)
268 {
269 struct kqop *kqop = base->evbase;
270 struct kevent *events = kqop->events;
271 struct kevent *changes;
272 struct timespec ts, *ts_p = NULL;
273 int i, n_changes, res;
274
275 if (tv != NULL) {
276 ts.tv_sec = tv->tv_sec;
277 ts.tv_nsec = tv->tv_usec * 1000;
278 ts_p = &ts;
279 }
280
281 /* Build "changes" from "base->changes" */
282 EVUTIL_ASSERT(kqop->changes);
283 n_changes = kq_build_changes_list(&base->changelist, kqop);
284 if (n_changes < 0)
285 return -1;
286
287 event_changelist_remove_all_(&base->changelist, base);
288
289 /* steal the changes array in case some broken code tries to call
290 * dispatch twice at once. */
291 changes = kqop->changes;
292 kqop->changes = NULL;
293
294 /* Make sure that 'events' is at least as long as the list of changes:
295 * otherwise errors in the changes can get reported as a -1 return
296 * value from kevent() rather than as EV_ERROR events in the events
297 * array.
298 *
299 * (We could instead handle -1 return values from kevent() by
300 * retrying with a smaller changes array or a larger events array,
301 * but this approach seems less risky for now.)
302 */
303 if (kqop->events_size < n_changes) {
304 int new_size = kqop->events_size;
305 do {
306 new_size *= 2;
307 } while (new_size < n_changes);
308
309 kq_grow_events(kqop, new_size);
310 events = kqop->events;
311 }
312
313 EVBASE_RELEASE_LOCK(base, th_base_lock);
314
315 res = kevent(kqop->kq, changes, n_changes,
316 events, kqop->events_size, ts_p);
317
318 EVBASE_ACQUIRE_LOCK(base, th_base_lock);
319
320 EVUTIL_ASSERT(kqop->changes == NULL);
321 kqop->changes = changes;
322
323 if (res == -1) {
324 if (errno != EINTR) {
325 event_warn("kevent");
326 return (-1);
327 }
328
329 return (0);
330 }
331
332 event_debug(("%s: kevent reports %d", __func__, res));
333
334 for (i = 0; i < res; i++) {
335 int which = 0;
336
337 if (events[i].flags & EV_ERROR) {
338 switch (events[i].data) {
339
340 /* Can occur on delete if we are not currently
341 * watching any events on this fd. That can
342 * happen when the fd was closed and another
343 * file was opened with that fd. */
344 case ENOENT:
345 /* Can occur for reasons not fully understood
346 * on FreeBSD. */
347 case EINVAL:
348 continue;
349 #if defined(__FreeBSD__)
350 /*
351 * This currently occurs if an FD is closed
352 * before the EV_DELETE makes it out via kevent().
353 * The FreeBSD capabilities code sees the blank
354 * capability set and rejects the request to
355 * modify an event.
356 *
357 * To be strictly correct - when an FD is closed,
358 * all the registered events are also removed.
359 * Queuing EV_DELETE to a closed FD is wrong.
360 * The event(s) should just be deleted from
361 * the pending changelist.
362 */
363 case ENOTCAPABLE:
364 continue;
365 #endif
366
367 /* Can occur on a delete if the fd is closed. */
368 case EBADF:
369 /* XXXX On NetBSD, we can also get EBADF if we
370 * try to add the write side of a pipe, but
371 * the read side has already been closed.
372 * Other BSDs call this situation 'EPIPE'. It
373 * would be good if we had a way to report
374 * this situation. */
375 continue;
376 /* These two can occur on an add if the fd was one side
377 * of a pipe, and the other side was closed. */
378 case EPERM:
379 case EPIPE:
380 /* Report read events, if we're listening for
381 * them, so that the user can learn about any
382 * add errors. (If the operation was a
383 * delete, then udata should be cleared.) */
384 if (events[i].udata) {
385 /* The operation was an add:
386 * report the error as a read. */
387 which |= EV_READ;
388 break;
389 } else {
390 /* The operation was a del:
391 * report nothing. */
392 continue;
393 }
394
395 /* Other errors shouldn't occur. */
396 default:
397 errno = events[i].data;
398 return (-1);
399 }
400 } else if (events[i].filter == EVFILT_READ) {
401 which |= EV_READ;
402 } else if (events[i].filter == EVFILT_WRITE) {
403 which |= EV_WRITE;
404 } else if (events[i].filter == EVFILT_SIGNAL) {
405 which |= EV_SIGNAL;
406 #ifdef EVFILT_USER
407 } else if (events[i].filter == EVFILT_USER) {
408 base->is_notify_pending = 0;
409 #endif
410 }
411
412 if (!which)
413 continue;
414
415 if (events[i].filter == EVFILT_SIGNAL) {
416 evmap_signal_active_(base, events[i].ident, 1);
417 } else {
418 evmap_io_active_(base, events[i].ident, which | EV_ET);
419 }
420 }
421
422 if (res == kqop->events_size) {
423 /* We used all the events space that we have. Maybe we should
424 make it bigger. */
425 kq_grow_events(kqop, kqop->events_size * 2);
426 }
427
428 return (0);
429 }
430
431 static void
kqop_free(struct kqop * kqop)432 kqop_free(struct kqop *kqop)
433 {
434 if (kqop->changes)
435 mm_free(kqop->changes);
436 if (kqop->events)
437 mm_free(kqop->events);
438 if (kqop->kq >= 0 && kqop->pid == getpid())
439 close(kqop->kq);
440 memset(kqop, 0, sizeof(struct kqop));
441 mm_free(kqop);
442 }
443
444 static void
kq_dealloc(struct event_base * base)445 kq_dealloc(struct event_base *base)
446 {
447 struct kqop *kqop = base->evbase;
448 evsig_dealloc_(base);
449 kqop_free(kqop);
450 }
451
452 /* signal handling */
453 static int
kq_sig_add(struct event_base * base,int nsignal,short old,short events,void * p)454 kq_sig_add(struct event_base *base, int nsignal, short old, short events, void *p)
455 {
456 struct kqop *kqop = base->evbase;
457 struct kevent kev;
458 struct timespec timeout = { 0, 0 };
459 (void)p;
460
461 EVUTIL_ASSERT(nsignal >= 0 && nsignal < NSIG);
462
463 memset(&kev, 0, sizeof(kev));
464 kev.ident = nsignal;
465 kev.filter = EVFILT_SIGNAL;
466 kev.flags = EV_ADD;
467
468 /* Be ready for the signal if it is sent any
469 * time between now and the next call to
470 * kq_dispatch. */
471 if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1)
472 return (-1);
473
474 /* We can set the handler for most signals to SIG_IGN and
475 * still have them reported to us in the queue. However,
476 * if the handler for SIGCHLD is SIG_IGN, the system reaps
477 * zombie processes for us, and we don't get any notification.
478 * This appears to be the only signal with this quirk. */
479 if (evsig_set_handler_(base, nsignal,
480 nsignal == SIGCHLD ? SIG_DFL : SIG_IGN) == -1)
481 return (-1);
482
483 return (0);
484 }
485
486 static int
kq_sig_del(struct event_base * base,int nsignal,short old,short events,void * p)487 kq_sig_del(struct event_base *base, int nsignal, short old, short events, void *p)
488 {
489 struct kqop *kqop = base->evbase;
490 struct kevent kev;
491
492 struct timespec timeout = { 0, 0 };
493 (void)p;
494
495 EVUTIL_ASSERT(nsignal >= 0 && nsignal < NSIG);
496
497 memset(&kev, 0, sizeof(kev));
498 kev.ident = nsignal;
499 kev.filter = EVFILT_SIGNAL;
500 kev.flags = EV_DELETE;
501
502 /* Because we insert signal events
503 * immediately, we need to delete them
504 * immediately, too */
505 if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1)
506 return (-1);
507
508 if (evsig_restore_handler_(base, nsignal) == -1)
509 return (-1);
510
511 return (0);
512 }
513
514
515 /* OSX 10.6 and FreeBSD 8.1 add support for EVFILT_USER, which we can use
516 * to wake up the event loop from another thread. */
517
518 /* Magic number we use for our filter ID. */
519 #define NOTIFY_IDENT 42
520
521 int
event_kq_add_notify_event_(struct event_base * base)522 event_kq_add_notify_event_(struct event_base *base)
523 {
524 struct kqop *kqop = base->evbase;
525 #if defined(EVFILT_USER) && defined(NOTE_TRIGGER)
526 struct kevent kev;
527 struct timespec timeout = { 0, 0 };
528 #endif
529
530 if (kqop->notify_event_added)
531 return 0;
532
533 #if defined(EVFILT_USER) && defined(NOTE_TRIGGER)
534 memset(&kev, 0, sizeof(kev));
535 kev.ident = NOTIFY_IDENT;
536 kev.filter = EVFILT_USER;
537 kev.flags = EV_ADD | EV_CLEAR;
538
539 if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1) {
540 event_warn("kevent: adding EVFILT_USER event");
541 return -1;
542 }
543
544 kqop->notify_event_added = 1;
545
546 return 0;
547 #else
548 return -1;
549 #endif
550 }
551
552 int
event_kq_notify_base_(struct event_base * base)553 event_kq_notify_base_(struct event_base *base)
554 {
555 struct kqop *kqop = base->evbase;
556 #if defined(EVFILT_USER) && defined(NOTE_TRIGGER)
557 struct kevent kev;
558 struct timespec timeout = { 0, 0 };
559 #endif
560 if (! kqop->notify_event_added)
561 return -1;
562
563 #if defined(EVFILT_USER) && defined(NOTE_TRIGGER)
564 memset(&kev, 0, sizeof(kev));
565 kev.ident = NOTIFY_IDENT;
566 kev.filter = EVFILT_USER;
567 kev.fflags = NOTE_TRIGGER;
568
569 if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1) {
570 event_warn("kevent: triggering EVFILT_USER event");
571 return -1;
572 }
573
574 return 0;
575 #else
576 return -1;
577 #endif
578 }
579
580 #endif /* EVENT__HAVE_KQUEUE */
581