FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_event.c
1 /* $NetBSD: kern_event.c,v 1.19 2004/02/14 11:56:28 jdolecek Exp $ */
2 /*-
3 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD: src/sys/kern/kern_event.c,v 1.27 2001/07/05 17:10:44 rwatson Exp $
28 */
29
30 #include <sys/cdefs.h>
31 __KERNEL_RCSID(0, "$NetBSD: kern_event.c,v 1.19 2004/02/14 11:56:28 jdolecek Exp $");
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/kernel.h>
36 #include <sys/proc.h>
37 #include <sys/malloc.h>
38 #include <sys/unistd.h>
39 #include <sys/file.h>
40 #include <sys/fcntl.h>
41 #include <sys/select.h>
42 #include <sys/queue.h>
43 #include <sys/event.h>
44 #include <sys/eventvar.h>
45 #include <sys/poll.h>
46 #include <sys/pool.h>
47 #include <sys/protosw.h>
48 #include <sys/socket.h>
49 #include <sys/socketvar.h>
50 #include <sys/stat.h>
51 #include <sys/uio.h>
52 #include <sys/mount.h>
53 #include <sys/filedesc.h>
54 #include <sys/sa.h>
55 #include <sys/syscallargs.h>
56
57 static int kqueue_scan(struct file *fp, size_t maxevents,
58 struct kevent *ulistp, const struct timespec *timeout,
59 struct proc *p, register_t *retval);
60 static void kqueue_wakeup(struct kqueue *kq);
61
62 static int kqueue_read(struct file *fp, off_t *offset, struct uio *uio,
63 struct ucred *cred, int flags);
64 static int kqueue_write(struct file *fp, off_t *offset, struct uio *uio,
65 struct ucred *cred, int flags);
66 static int kqueue_ioctl(struct file *fp, u_long com, void *data,
67 struct proc *p);
68 static int kqueue_fcntl(struct file *fp, u_int com, void *data,
69 struct proc *p);
70 static int kqueue_poll(struct file *fp, int events, struct proc *p);
71 static int kqueue_kqfilter(struct file *fp, struct knote *kn);
72 static int kqueue_stat(struct file *fp, struct stat *sp, struct proc *p);
73 static int kqueue_close(struct file *fp, struct proc *p);
74
75 static struct fileops kqueueops = {
76 kqueue_read, kqueue_write, kqueue_ioctl, kqueue_fcntl, kqueue_poll,
77 kqueue_stat, kqueue_close, kqueue_kqfilter
78 };
79
80 static void knote_attach(struct knote *kn, struct filedesc *fdp);
81 static void knote_drop(struct knote *kn, struct proc *p,
82 struct filedesc *fdp);
83 static void knote_enqueue(struct knote *kn);
84 static void knote_dequeue(struct knote *kn);
85
86 static void filt_kqdetach(struct knote *kn);
87 static int filt_kqueue(struct knote *kn, long hint);
88 static int filt_procattach(struct knote *kn);
89 static void filt_procdetach(struct knote *kn);
90 static int filt_proc(struct knote *kn, long hint);
91 static int filt_fileattach(struct knote *kn);
92 static void filt_timerexpire(void *knx);
93 static int filt_timerattach(struct knote *kn);
94 static void filt_timerdetach(struct knote *kn);
95 static int filt_timer(struct knote *kn, long hint);
96
97 static const struct filterops kqread_filtops =
98 { 1, NULL, filt_kqdetach, filt_kqueue };
99 static const struct filterops proc_filtops =
100 { 0, filt_procattach, filt_procdetach, filt_proc };
101 static const struct filterops file_filtops =
102 { 1, filt_fileattach, NULL, NULL };
103 static struct filterops timer_filtops =
104 { 0, filt_timerattach, filt_timerdetach, filt_timer };
105
106 struct pool kqueue_pool;
107 struct pool knote_pool;
108 static int kq_ncallouts = 0;
109 static int kq_calloutmax = (4 * 1024);
110
111 MALLOC_DEFINE(M_KEVENT, "kevent", "kevents/knotes");
112
113 #define KNOTE_ACTIVATE(kn) \
114 do { \
115 kn->kn_status |= KN_ACTIVE; \
116 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
117 knote_enqueue(kn); \
118 } while(0)
119
120 #define KN_HASHSIZE 64 /* XXX should be tunable */
121 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
122
123 extern const struct filterops sig_filtops;
124
125 /*
126 * Table for for all system-defined filters.
127 * These should be listed in the numeric order of the EVFILT_* defines.
128 * If filtops is NULL, the filter isn't implemented in NetBSD.
129 * End of list is when name is NULL.
130 */
131 struct kfilter {
132 const char *name; /* name of filter */
133 uint32_t filter; /* id of filter */
134 const struct filterops *filtops;/* operations for filter */
135 };
136
137 /* System defined filters */
138 static const struct kfilter sys_kfilters[] = {
139 { "EVFILT_READ", EVFILT_READ, &file_filtops },
140 { "EVFILT_WRITE", EVFILT_WRITE, &file_filtops },
141 { "EVFILT_AIO", EVFILT_AIO, NULL },
142 { "EVFILT_VNODE", EVFILT_VNODE, &file_filtops },
143 { "EVFILT_PROC", EVFILT_PROC, &proc_filtops },
144 { "EVFILT_SIGNAL", EVFILT_SIGNAL, &sig_filtops },
145 { "EVFILT_TIMER", EVFILT_TIMER, &timer_filtops },
146 { NULL, 0, NULL }, /* end of list */
147 };
148
149 /* User defined kfilters */
150 static struct kfilter *user_kfilters; /* array */
151 static int user_kfilterc; /* current offset */
152 static int user_kfiltermaxc; /* max size so far */
153
154 /*
155 * kqueue_init:
156 *
157 * Initialize the kqueue/knote facility.
158 */
159 void
160 kqueue_init(void)
161 {
162
163 pool_init(&kqueue_pool, sizeof(struct kqueue), 0, 0, 0, "kqueuepl",
164 NULL);
165 pool_init(&knote_pool, sizeof(struct knote), 0, 0, 0, "knotepl",
166 NULL);
167 }
168
169 /*
170 * Find kfilter entry by name, or NULL if not found.
171 */
172 static const struct kfilter *
173 kfilter_byname_sys(const char *name)
174 {
175 int i;
176
177 for (i = 0; sys_kfilters[i].name != NULL; i++) {
178 if (strcmp(name, sys_kfilters[i].name) == 0)
179 return (&sys_kfilters[i]);
180 }
181 return (NULL);
182 }
183
184 static struct kfilter *
185 kfilter_byname_user(const char *name)
186 {
187 int i;
188
189 /* user_kfilters[] could be NULL if no filters were registered */
190 if (!user_kfilters)
191 return (NULL);
192
193 for (i = 0; user_kfilters[i].name != NULL; i++) {
194 if (user_kfilters[i].name != '\0' &&
195 strcmp(name, user_kfilters[i].name) == 0)
196 return (&user_kfilters[i]);
197 }
198 return (NULL);
199 }
200
201 static const struct kfilter *
202 kfilter_byname(const char *name)
203 {
204 const struct kfilter *kfilter;
205
206 if ((kfilter = kfilter_byname_sys(name)) != NULL)
207 return (kfilter);
208
209 return (kfilter_byname_user(name));
210 }
211
212 /*
213 * Find kfilter entry by filter id, or NULL if not found.
214 * Assumes entries are indexed in filter id order, for speed.
215 */
216 static const struct kfilter *
217 kfilter_byfilter(uint32_t filter)
218 {
219 const struct kfilter *kfilter;
220
221 if (filter < EVFILT_SYSCOUNT) /* it's a system filter */
222 kfilter = &sys_kfilters[filter];
223 else if (user_kfilters != NULL &&
224 filter < EVFILT_SYSCOUNT + user_kfilterc)
225 /* it's a user filter */
226 kfilter = &user_kfilters[filter - EVFILT_SYSCOUNT];
227 else
228 return (NULL); /* out of range */
229 KASSERT(kfilter->filter == filter); /* sanity check! */
230 return (kfilter);
231 }
232
233 /*
234 * Register a new kfilter. Stores the entry in user_kfilters.
235 * Returns 0 if operation succeeded, or an appropriate errno(2) otherwise.
236 * If retfilter != NULL, the new filterid is returned in it.
237 */
238 int
239 kfilter_register(const char *name, const struct filterops *filtops,
240 int *retfilter)
241 {
242 struct kfilter *kfilter;
243 void *space;
244 int len;
245
246 if (name == NULL || name[0] == '\0' || filtops == NULL)
247 return (EINVAL); /* invalid args */
248 if (kfilter_byname(name) != NULL)
249 return (EEXIST); /* already exists */
250 if (user_kfilterc > 0xffffffff - EVFILT_SYSCOUNT)
251 return (EINVAL); /* too many */
252
253 /* check if need to grow user_kfilters */
254 if (user_kfilterc + 1 > user_kfiltermaxc) {
255 /*
256 * Grow in KFILTER_EXTENT chunks. Use malloc(9), because we
257 * want to traverse user_kfilters as an array.
258 */
259 user_kfiltermaxc += KFILTER_EXTENT;
260 kfilter = malloc(user_kfiltermaxc * sizeof(struct filter *),
261 M_KEVENT, M_WAITOK);
262
263 /* copy existing user_kfilters */
264 if (user_kfilters != NULL)
265 memcpy((caddr_t)kfilter, (caddr_t)user_kfilters,
266 user_kfilterc * sizeof(struct kfilter *));
267 /* zero new sections */
268 memset((caddr_t)kfilter +
269 user_kfilterc * sizeof(struct kfilter *), 0,
270 (user_kfiltermaxc - user_kfilterc) *
271 sizeof(struct kfilter *));
272 /* switch to new kfilter */
273 if (user_kfilters != NULL)
274 free(user_kfilters, M_KEVENT);
275 user_kfilters = kfilter;
276 }
277 len = strlen(name) + 1; /* copy name */
278 space = malloc(len, M_KEVENT, M_WAITOK);
279 memcpy(space, name, len);
280 user_kfilters[user_kfilterc].name = space;
281
282 user_kfilters[user_kfilterc].filter = user_kfilterc + EVFILT_SYSCOUNT;
283
284 len = sizeof(struct filterops); /* copy filtops */
285 space = malloc(len, M_KEVENT, M_WAITOK);
286 memcpy(space, filtops, len);
287 user_kfilters[user_kfilterc].filtops = space;
288
289 if (retfilter != NULL)
290 *retfilter = user_kfilters[user_kfilterc].filter;
291 user_kfilterc++; /* finally, increment count */
292 return (0);
293 }
294
295 /*
296 * Unregister a kfilter previously registered with kfilter_register.
297 * This retains the filter id, but clears the name and frees filtops (filter
298 * operations), so that the number isn't reused during a boot.
299 * Returns 0 if operation succeeded, or an appropriate errno(2) otherwise.
300 */
301 int
302 kfilter_unregister(const char *name)
303 {
304 struct kfilter *kfilter;
305
306 if (name == NULL || name[0] == '\0')
307 return (EINVAL); /* invalid name */
308
309 if (kfilter_byname_sys(name) != NULL)
310 return (EINVAL); /* can't detach system filters */
311
312 kfilter = kfilter_byname_user(name);
313 if (kfilter == NULL) /* not found */
314 return (ENOENT);
315
316 if (kfilter->name[0] != '\0') {
317 /* XXX Cast away const (but we know it's safe. */
318 free((void *) kfilter->name, M_KEVENT);
319 kfilter->name = ""; /* mark as `not implemented' */
320 }
321 if (kfilter->filtops != NULL) {
322 /* XXX Cast away const (but we know it's safe. */
323 free((void *) kfilter->filtops, M_KEVENT);
324 kfilter->filtops = NULL; /* mark as `not implemented' */
325 }
326 return (0);
327 }
328
329
330 /*
331 * Filter attach method for EVFILT_READ and EVFILT_WRITE on normal file
332 * descriptors. Calls struct fileops kqfilter method for given file descriptor.
333 */
334 static int
335 filt_fileattach(struct knote *kn)
336 {
337 struct file *fp;
338
339 fp = kn->kn_fp;
340 return ((*fp->f_ops->fo_kqfilter)(fp, kn));
341 }
342
343 /*
344 * Filter detach method for EVFILT_READ on kqueue descriptor.
345 */
346 static void
347 filt_kqdetach(struct knote *kn)
348 {
349 struct kqueue *kq;
350
351 kq = (struct kqueue *)kn->kn_fp->f_data;
352 SLIST_REMOVE(&kq->kq_sel.sel_klist, kn, knote, kn_selnext);
353 }
354
355 /*
356 * Filter event method for EVFILT_READ on kqueue descriptor.
357 */
358 /*ARGSUSED*/
359 static int
360 filt_kqueue(struct knote *kn, long hint)
361 {
362 struct kqueue *kq;
363
364 kq = (struct kqueue *)kn->kn_fp->f_data;
365 kn->kn_data = kq->kq_count;
366 return (kn->kn_data > 0);
367 }
368
369 /*
370 * Filter attach method for EVFILT_PROC.
371 */
372 static int
373 filt_procattach(struct knote *kn)
374 {
375 struct proc *p;
376
377 p = pfind(kn->kn_id);
378 if (p == NULL)
379 return (ESRCH);
380
381 /*
382 * Fail if it's not owned by you, or the last exec gave us
383 * setuid/setgid privs (unless you're root).
384 */
385 if ((p->p_cred->p_ruid != curproc->p_cred->p_ruid ||
386 (p->p_flag & P_SUGID))
387 && suser(curproc->p_ucred, &curproc->p_acflag) != 0)
388 return (EACCES);
389
390 kn->kn_ptr.p_proc = p;
391 kn->kn_flags |= EV_CLEAR; /* automatically set */
392
393 /*
394 * internal flag indicating registration done by kernel
395 */
396 if (kn->kn_flags & EV_FLAG1) {
397 kn->kn_data = kn->kn_sdata; /* ppid */
398 kn->kn_fflags = NOTE_CHILD;
399 kn->kn_flags &= ~EV_FLAG1;
400 }
401
402 /* XXXSMP lock the process? */
403 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
404
405 return (0);
406 }
407
408 /*
409 * Filter detach method for EVFILT_PROC.
410 *
411 * The knote may be attached to a different process, which may exit,
412 * leaving nothing for the knote to be attached to. So when the process
413 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
414 * it will be deleted when read out. However, as part of the knote deletion,
415 * this routine is called, so a check is needed to avoid actually performing
416 * a detach, because the original process might not exist any more.
417 */
418 static void
419 filt_procdetach(struct knote *kn)
420 {
421 struct proc *p;
422
423 if (kn->kn_status & KN_DETACHED)
424 return;
425
426 p = kn->kn_ptr.p_proc;
427 KASSERT(p->p_stat == SZOMB || pfind(kn->kn_id) == p);
428
429 /* XXXSMP lock the process? */
430 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
431 }
432
433 /*
434 * Filter event method for EVFILT_PROC.
435 */
436 static int
437 filt_proc(struct knote *kn, long hint)
438 {
439 u_int event;
440
441 /*
442 * mask off extra data
443 */
444 event = (u_int)hint & NOTE_PCTRLMASK;
445
446 /*
447 * if the user is interested in this event, record it.
448 */
449 if (kn->kn_sfflags & event)
450 kn->kn_fflags |= event;
451
452 /*
453 * process is gone, so flag the event as finished.
454 */
455 if (event == NOTE_EXIT) {
456 /*
457 * Detach the knote from watched process and mark
458 * it as such. We can't leave this to kqueue_scan(),
459 * since the process might not exist by then. And we
460 * have to do this now, since psignal KNOTE() is called
461 * also for zombies and we might end up reading freed
462 * memory if the kevent would already be picked up
463 * and knote g/c'ed.
464 */
465 kn->kn_fop->f_detach(kn);
466 kn->kn_status |= KN_DETACHED;
467
468 /* Mark as ONESHOT, so that the knote it g/c'ed when read */
469 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
470 return (1);
471 }
472
473 /*
474 * process forked, and user wants to track the new process,
475 * so attach a new knote to it, and immediately report an
476 * event with the parent's pid.
477 */
478 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
479 struct kevent kev;
480 int error;
481
482 /*
483 * register knote with new process.
484 */
485 kev.ident = hint & NOTE_PDATAMASK; /* pid */
486 kev.filter = kn->kn_filter;
487 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
488 kev.fflags = kn->kn_sfflags;
489 kev.data = kn->kn_id; /* parent */
490 kev.udata = kn->kn_kevent.udata; /* preserve udata */
491 error = kqueue_register(kn->kn_kq, &kev, NULL);
492 if (error)
493 kn->kn_fflags |= NOTE_TRACKERR;
494 }
495
496 return (kn->kn_fflags != 0);
497 }
498
499 static void
500 filt_timerexpire(void *knx)
501 {
502 struct knote *kn = knx;
503 int tticks;
504
505 kn->kn_data++;
506 KNOTE_ACTIVATE(kn);
507
508 if ((kn->kn_flags & EV_ONESHOT) == 0) {
509 tticks = mstohz(kn->kn_sdata);
510 callout_schedule((struct callout *)kn->kn_hook, tticks);
511 }
512 }
513
514 /*
515 * data contains amount of time to sleep, in milliseconds
516 */
517 static int
518 filt_timerattach(struct knote *kn)
519 {
520 struct callout *calloutp;
521 int tticks;
522
523 if (kq_ncallouts >= kq_calloutmax)
524 return (ENOMEM);
525 kq_ncallouts++;
526
527 tticks = mstohz(kn->kn_sdata);
528
529 /* if the supplied value is under our resolution, use 1 tick */
530 if (tticks == 0) {
531 if (kn->kn_sdata == 0)
532 return (EINVAL);
533 tticks = 1;
534 }
535
536 kn->kn_flags |= EV_CLEAR; /* automatically set */
537 MALLOC(calloutp, struct callout *, sizeof(*calloutp),
538 M_KEVENT, 0);
539 callout_init(calloutp);
540 callout_reset(calloutp, tticks, filt_timerexpire, kn);
541 kn->kn_hook = calloutp;
542
543 return (0);
544 }
545
546 static void
547 filt_timerdetach(struct knote *kn)
548 {
549 struct callout *calloutp;
550
551 calloutp = (struct callout *)kn->kn_hook;
552 callout_stop(calloutp);
553 FREE(calloutp, M_KEVENT);
554 kq_ncallouts--;
555 }
556
557 static int
558 filt_timer(struct knote *kn, long hint)
559 {
560 return (kn->kn_data != 0);
561 }
562
563 /*
564 * filt_seltrue:
565 *
566 * This filter "event" routine simulates seltrue().
567 */
568 int
569 filt_seltrue(struct knote *kn, long hint)
570 {
571
572 /*
573 * We don't know how much data can be read/written,
574 * but we know that it *can* be. This is about as
575 * good as select/poll does as well.
576 */
577 kn->kn_data = 0;
578 return (1);
579 }
580
581 /*
582 * This provides full kqfilter entry for device switch tables, which
583 * has same effect as filter using filt_seltrue() as filter method.
584 */
585 static void
586 filt_seltruedetach(struct knote *kn)
587 {
588 /* Nothing to do */
589 }
590
591 static const struct filterops seltrue_filtops =
592 { 1, NULL, filt_seltruedetach, filt_seltrue };
593
594 int
595 seltrue_kqfilter(dev_t dev, struct knote *kn)
596 {
597 switch (kn->kn_filter) {
598 case EVFILT_READ:
599 case EVFILT_WRITE:
600 kn->kn_fop = &seltrue_filtops;
601 break;
602 default:
603 return (1);
604 }
605
606 /* Nothing more to do */
607 return (0);
608 }
609
610 /*
611 * kqueue(2) system call.
612 */
613 int
614 sys_kqueue(struct lwp *l, void *v, register_t *retval)
615 {
616 struct filedesc *fdp;
617 struct kqueue *kq;
618 struct file *fp;
619 struct proc *p;
620 int fd, error;
621
622 p = l->l_proc;
623 fdp = p->p_fd;
624 error = falloc(p, &fp, &fd); /* setup a new file descriptor */
625 if (error)
626 return (error);
627 fp->f_flag = FREAD | FWRITE;
628 fp->f_type = DTYPE_KQUEUE;
629 fp->f_ops = &kqueueops;
630 kq = pool_get(&kqueue_pool, PR_WAITOK);
631 memset((char *)kq, 0, sizeof(struct kqueue));
632 simple_lock_init(&kq->kq_lock);
633 TAILQ_INIT(&kq->kq_head);
634 fp->f_data = (caddr_t)kq; /* store the kqueue with the fp */
635 *retval = fd;
636 if (fdp->fd_knlistsize < 0)
637 fdp->fd_knlistsize = 0; /* this process has a kq */
638 kq->kq_fdp = fdp;
639 FILE_SET_MATURE(fp);
640 FILE_UNUSE(fp, p); /* falloc() does FILE_USE() */
641 return (error);
642 }
643
644 /*
645 * kevent(2) system call.
646 */
647 int
648 sys_kevent(struct lwp *l, void *v, register_t *retval)
649 {
650 struct sys_kevent_args /* {
651 syscallarg(int) fd;
652 syscallarg(const struct kevent *) changelist;
653 syscallarg(size_t) nchanges;
654 syscallarg(struct kevent *) eventlist;
655 syscallarg(size_t) nevents;
656 syscallarg(const struct timespec *) timeout;
657 } */ *uap = v;
658 struct kevent *kevp;
659 struct kqueue *kq;
660 struct file *fp;
661 struct timespec ts;
662 struct proc *p;
663 size_t i, n;
664 int nerrors, error;
665
666 p = l->l_proc;
667 /* check that we're dealing with a kq */
668 fp = fd_getfile(p->p_fd, SCARG(uap, fd));
669 if (fp == NULL)
670 return (EBADF);
671
672 if (fp->f_type != DTYPE_KQUEUE) {
673 simple_unlock(&fp->f_slock);
674 return (EBADF);
675 }
676
677 FILE_USE(fp);
678
679 if (SCARG(uap, timeout) != NULL) {
680 error = copyin(SCARG(uap, timeout), &ts, sizeof(ts));
681 if (error)
682 goto done;
683 SCARG(uap, timeout) = &ts;
684 }
685
686 kq = (struct kqueue *)fp->f_data;
687 nerrors = 0;
688
689 /* traverse list of events to register */
690 while (SCARG(uap, nchanges) > 0) {
691 /* copyin a maximum of KQ_EVENTS at each pass */
692 n = MIN(SCARG(uap, nchanges), KQ_NEVENTS);
693 error = copyin(SCARG(uap, changelist), kq->kq_kev,
694 n * sizeof(struct kevent));
695 if (error)
696 goto done;
697 for (i = 0; i < n; i++) {
698 kevp = &kq->kq_kev[i];
699 kevp->flags &= ~EV_SYSFLAGS;
700 /* register each knote */
701 error = kqueue_register(kq, kevp, p);
702 if (error) {
703 if (SCARG(uap, nevents) != 0) {
704 kevp->flags = EV_ERROR;
705 kevp->data = error;
706 error = copyout((caddr_t)kevp,
707 (caddr_t)SCARG(uap, eventlist),
708 sizeof(*kevp));
709 if (error)
710 goto done;
711 SCARG(uap, eventlist)++;
712 SCARG(uap, nevents)--;
713 nerrors++;
714 } else {
715 goto done;
716 }
717 }
718 }
719 SCARG(uap, nchanges) -= n; /* update the results */
720 SCARG(uap, changelist) += n;
721 }
722 if (nerrors) {
723 *retval = nerrors;
724 error = 0;
725 goto done;
726 }
727
728 /* actually scan through the events */
729 error = kqueue_scan(fp, SCARG(uap, nevents), SCARG(uap, eventlist),
730 SCARG(uap, timeout), p, retval);
731 done:
732 FILE_UNUSE(fp, p);
733 return (error);
734 }
735
736 /*
737 * Register a given kevent kev onto the kqueue
738 */
739 int
740 kqueue_register(struct kqueue *kq, struct kevent *kev, struct proc *p)
741 {
742 const struct kfilter *kfilter;
743 struct filedesc *fdp;
744 struct file *fp;
745 struct knote *kn;
746 int s, error;
747
748 fdp = kq->kq_fdp;
749 fp = NULL;
750 kn = NULL;
751 error = 0;
752 kfilter = kfilter_byfilter(kev->filter);
753 if (kfilter == NULL || kfilter->filtops == NULL) {
754 /* filter not found nor implemented */
755 return (EINVAL);
756 }
757
758 /* search if knote already exists */
759 if (kfilter->filtops->f_isfd) {
760 /* monitoring a file descriptor */
761 if ((fp = fd_getfile(fdp, kev->ident)) == NULL)
762 return (EBADF); /* validate descriptor */
763 FILE_USE(fp);
764
765 if (kev->ident < fdp->fd_knlistsize) {
766 SLIST_FOREACH(kn, &fdp->fd_knlist[kev->ident], kn_link)
767 if (kq == kn->kn_kq &&
768 kev->filter == kn->kn_filter)
769 break;
770 }
771 } else {
772 /*
773 * not monitoring a file descriptor, so
774 * lookup knotes in internal hash table
775 */
776 if (fdp->fd_knhashmask != 0) {
777 struct klist *list;
778
779 list = &fdp->fd_knhash[
780 KN_HASH((u_long)kev->ident, fdp->fd_knhashmask)];
781 SLIST_FOREACH(kn, list, kn_link)
782 if (kev->ident == kn->kn_id &&
783 kq == kn->kn_kq &&
784 kev->filter == kn->kn_filter)
785 break;
786 }
787 }
788
789 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
790 error = ENOENT; /* filter not found */
791 goto done;
792 }
793
794 /*
795 * kn now contains the matching knote, or NULL if no match
796 */
797 if (kev->flags & EV_ADD) {
798 /* add knote */
799
800 if (kn == NULL) {
801 /* create new knote */
802 kn = pool_get(&knote_pool, PR_WAITOK);
803 if (kn == NULL) {
804 error = ENOMEM;
805 goto done;
806 }
807 kn->kn_fp = fp;
808 kn->kn_kq = kq;
809 kn->kn_fop = kfilter->filtops;
810
811 /*
812 * apply reference count to knote structure, and
813 * do not release it at the end of this routine.
814 */
815 fp = NULL;
816
817 kn->kn_sfflags = kev->fflags;
818 kn->kn_sdata = kev->data;
819 kev->fflags = 0;
820 kev->data = 0;
821 kn->kn_kevent = *kev;
822
823 knote_attach(kn, fdp);
824 if ((error = kfilter->filtops->f_attach(kn)) != 0) {
825 knote_drop(kn, p, fdp);
826 goto done;
827 }
828 } else {
829 /* modify existing knote */
830
831 /*
832 * The user may change some filter values after the
833 * initial EV_ADD, but doing so will not reset any
834 * filter which have already been triggered.
835 */
836 kn->kn_sfflags = kev->fflags;
837 kn->kn_sdata = kev->data;
838 kn->kn_kevent.udata = kev->udata;
839 }
840
841 s = splsched();
842 if (kn->kn_fop->f_event(kn, 0))
843 KNOTE_ACTIVATE(kn);
844 splx(s);
845
846 } else if (kev->flags & EV_DELETE) { /* delete knote */
847 kn->kn_fop->f_detach(kn);
848 knote_drop(kn, p, fdp);
849 goto done;
850 }
851
852 /* disable knote */
853 if ((kev->flags & EV_DISABLE) &&
854 ((kn->kn_status & KN_DISABLED) == 0)) {
855 s = splsched();
856 kn->kn_status |= KN_DISABLED;
857 splx(s);
858 }
859
860 /* enable knote */
861 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
862 s = splsched();
863 kn->kn_status &= ~KN_DISABLED;
864 if ((kn->kn_status & KN_ACTIVE) &&
865 ((kn->kn_status & KN_QUEUED) == 0))
866 knote_enqueue(kn);
867 splx(s);
868 }
869
870 done:
871 if (fp != NULL)
872 FILE_UNUSE(fp, p);
873 return (error);
874 }
875
876 /*
877 * Scan through the list of events on fp (for a maximum of maxevents),
878 * returning the results in to ulistp. Timeout is determined by tsp; if
879 * NULL, wait indefinitely, if 0 valued, perform a poll, otherwise wait
880 * as appropriate.
881 */
882 static int
883 kqueue_scan(struct file *fp, size_t maxevents, struct kevent *ulistp,
884 const struct timespec *tsp, struct proc *p, register_t *retval)
885 {
886 struct kqueue *kq;
887 struct kevent *kevp;
888 struct timeval atv;
889 struct knote *kn, *marker=NULL;
890 size_t count, nkev;
891 int s, timeout, error;
892
893 kq = (struct kqueue *)fp->f_data;
894 count = maxevents;
895 nkev = error = 0;
896 if (count == 0)
897 goto done;
898
899 if (tsp) { /* timeout supplied */
900 TIMESPEC_TO_TIMEVAL(&atv, tsp);
901 if (itimerfix(&atv)) {
902 error = EINVAL;
903 goto done;
904 }
905 s = splclock();
906 timeradd(&atv, &time, &atv); /* calc. time to wait until */
907 splx(s);
908 timeout = hzto(&atv);
909 if (timeout <= 0)
910 timeout = -1; /* do poll */
911 } else {
912 /* no timeout, wait forever */
913 timeout = 0;
914 }
915
916 MALLOC(marker, struct knote *, sizeof(*marker), M_KEVENT, M_WAITOK);
917 memset(marker, 0, sizeof(*marker));
918
919 goto start;
920
921 retry:
922 if (tsp) {
923 /*
924 * We have to recalculate the timeout on every retry.
925 */
926 timeout = hzto(&atv);
927 if (timeout <= 0)
928 goto done;
929 }
930
931 start:
932 kevp = kq->kq_kev;
933 s = splsched();
934 simple_lock(&kq->kq_lock);
935 if (kq->kq_count == 0) {
936 if (timeout < 0) {
937 error = EWOULDBLOCK;
938 simple_unlock(&kq->kq_lock);
939 } else {
940 kq->kq_state |= KQ_SLEEP;
941 error = ltsleep(kq, PSOCK | PCATCH | PNORELOCK,
942 "kqread", timeout, &kq->kq_lock);
943 }
944 splx(s);
945 if (error == 0)
946 goto retry;
947 /* don't restart after signals... */
948 if (error == ERESTART)
949 error = EINTR;
950 else if (error == EWOULDBLOCK)
951 error = 0;
952 goto done;
953 }
954
955 /* mark end of knote list */
956 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
957 simple_unlock(&kq->kq_lock);
958
959 while (count) { /* while user wants data ... */
960 simple_lock(&kq->kq_lock);
961 kn = TAILQ_FIRST(&kq->kq_head); /* get next knote */
962 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
963 if (kn == marker) { /* if it's our marker, stop */
964 /* What if it's some else's marker? */
965 simple_unlock(&kq->kq_lock);
966 splx(s);
967 if (count == maxevents)
968 goto retry;
969 goto done;
970 }
971 kq->kq_count--;
972 simple_unlock(&kq->kq_lock);
973
974 if (kn->kn_status & KN_DISABLED) {
975 /* don't want disabled events */
976 kn->kn_status &= ~KN_QUEUED;
977 continue;
978 }
979 if ((kn->kn_flags & EV_ONESHOT) == 0 &&
980 kn->kn_fop->f_event(kn, 0) == 0) {
981 /*
982 * non-ONESHOT event that hasn't
983 * triggered again, so de-queue.
984 */
985 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
986 continue;
987 }
988 *kevp = kn->kn_kevent;
989 kevp++;
990 nkev++;
991 if (kn->kn_flags & EV_ONESHOT) {
992 /* delete ONESHOT events after retrieval */
993 kn->kn_status &= ~KN_QUEUED;
994 splx(s);
995 kn->kn_fop->f_detach(kn);
996 knote_drop(kn, p, p->p_fd);
997 s = splsched();
998 } else if (kn->kn_flags & EV_CLEAR) {
999 /* clear state after retrieval */
1000 kn->kn_data = 0;
1001 kn->kn_fflags = 0;
1002 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
1003 } else {
1004 /* add event back on list */
1005 simple_lock(&kq->kq_lock);
1006 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
1007 kq->kq_count++;
1008 simple_unlock(&kq->kq_lock);
1009 }
1010 count--;
1011 if (nkev == KQ_NEVENTS) {
1012 /* do copyouts in KQ_NEVENTS chunks */
1013 splx(s);
1014 error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
1015 sizeof(struct kevent) * nkev);
1016 ulistp += nkev;
1017 nkev = 0;
1018 kevp = kq->kq_kev;
1019 s = splsched();
1020 if (error)
1021 break;
1022 }
1023 }
1024
1025 /* remove marker */
1026 simple_lock(&kq->kq_lock);
1027 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
1028 simple_unlock(&kq->kq_lock);
1029 splx(s);
1030 done:
1031 if (marker)
1032 FREE(marker, M_KEVENT);
1033
1034 if (nkev != 0) {
1035 /* copyout remaining events */
1036 error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
1037 sizeof(struct kevent) * nkev);
1038 }
1039 *retval = maxevents - count;
1040
1041 return (error);
1042 }
1043
1044 /*
1045 * struct fileops read method for a kqueue descriptor.
1046 * Not implemented.
1047 * XXX: This could be expanded to call kqueue_scan, if desired.
1048 */
1049 /*ARGSUSED*/
1050 static int
1051 kqueue_read(struct file *fp, off_t *offset, struct uio *uio,
1052 struct ucred *cred, int flags)
1053 {
1054
1055 return (ENXIO);
1056 }
1057
1058 /*
1059 * struct fileops write method for a kqueue descriptor.
1060 * Not implemented.
1061 */
1062 /*ARGSUSED*/
1063 static int
1064 kqueue_write(struct file *fp, off_t *offset, struct uio *uio,
1065 struct ucred *cred, int flags)
1066 {
1067
1068 return (ENXIO);
1069 }
1070
1071 /*
1072 * struct fileops ioctl method for a kqueue descriptor.
1073 *
1074 * Two ioctls are currently supported. They both use struct kfilter_mapping:
1075 * KFILTER_BYNAME find name for filter, and return result in
1076 * name, which is of size len.
1077 * KFILTER_BYFILTER find filter for name. len is ignored.
1078 */
1079 /*ARGSUSED*/
1080 static int
1081 kqueue_ioctl(struct file *fp, u_long com, void *data, struct proc *p)
1082 {
1083 struct kfilter_mapping *km;
1084 const struct kfilter *kfilter;
1085 char *name;
1086 int error;
1087
1088 km = (struct kfilter_mapping *)data;
1089 error = 0;
1090
1091 switch (com) {
1092 case KFILTER_BYFILTER: /* convert filter -> name */
1093 kfilter = kfilter_byfilter(km->filter);
1094 if (kfilter != NULL)
1095 error = copyoutstr(kfilter->name, km->name, km->len,
1096 NULL);
1097 else
1098 error = ENOENT;
1099 break;
1100
1101 case KFILTER_BYNAME: /* convert name -> filter */
1102 MALLOC(name, char *, KFILTER_MAXNAME, M_KEVENT, M_WAITOK);
1103 error = copyinstr(km->name, name, KFILTER_MAXNAME, NULL);
1104 if (error) {
1105 FREE(name, M_KEVENT);
1106 break;
1107 }
1108 kfilter = kfilter_byname(name);
1109 if (kfilter != NULL)
1110 km->filter = kfilter->filter;
1111 else
1112 error = ENOENT;
1113 FREE(name, M_KEVENT);
1114 break;
1115
1116 default:
1117 error = ENOTTY;
1118
1119 }
1120 return (error);
1121 }
1122
1123 /*
1124 * struct fileops fcntl method for a kqueue descriptor.
1125 * Not implemented.
1126 */
1127 /*ARGSUSED*/
1128 static int
1129 kqueue_fcntl(struct file *fp, u_int com, void *data, struct proc *p)
1130 {
1131
1132 return (ENOTTY);
1133 }
1134
1135 /*
1136 * struct fileops poll method for a kqueue descriptor.
1137 * Determine if kqueue has events pending.
1138 */
1139 static int
1140 kqueue_poll(struct file *fp, int events, struct proc *p)
1141 {
1142 struct kqueue *kq;
1143 int revents;
1144
1145 kq = (struct kqueue *)fp->f_data;
1146 revents = 0;
1147 if (events & (POLLIN | POLLRDNORM)) {
1148 if (kq->kq_count) {
1149 revents |= events & (POLLIN | POLLRDNORM);
1150 } else {
1151 selrecord(p, &kq->kq_sel);
1152 }
1153 }
1154 return (revents);
1155 }
1156
1157 /*
1158 * struct fileops stat method for a kqueue descriptor.
1159 * Returns dummy info, with st_size being number of events pending.
1160 */
1161 static int
1162 kqueue_stat(struct file *fp, struct stat *st, struct proc *p)
1163 {
1164 struct kqueue *kq;
1165
1166 kq = (struct kqueue *)fp->f_data;
1167 memset((void *)st, 0, sizeof(*st));
1168 st->st_size = kq->kq_count;
1169 st->st_blksize = sizeof(struct kevent);
1170 st->st_mode = S_IFIFO;
1171 return (0);
1172 }
1173
1174 /*
1175 * struct fileops close method for a kqueue descriptor.
1176 * Cleans up kqueue.
1177 */
1178 static int
1179 kqueue_close(struct file *fp, struct proc *p)
1180 {
1181 struct kqueue *kq;
1182 struct filedesc *fdp;
1183 struct knote **knp, *kn, *kn0;
1184 int i;
1185
1186 kq = (struct kqueue *)fp->f_data;
1187 fdp = p->p_fd;
1188 for (i = 0; i < fdp->fd_knlistsize; i++) {
1189 knp = &SLIST_FIRST(&fdp->fd_knlist[i]);
1190 kn = *knp;
1191 while (kn != NULL) {
1192 kn0 = SLIST_NEXT(kn, kn_link);
1193 if (kq == kn->kn_kq) {
1194 kn->kn_fop->f_detach(kn);
1195 FILE_UNUSE(kn->kn_fp, p);
1196 pool_put(&knote_pool, kn);
1197 *knp = kn0;
1198 } else {
1199 knp = &SLIST_NEXT(kn, kn_link);
1200 }
1201 kn = kn0;
1202 }
1203 }
1204 if (fdp->fd_knhashmask != 0) {
1205 for (i = 0; i < fdp->fd_knhashmask + 1; i++) {
1206 knp = &SLIST_FIRST(&fdp->fd_knhash[i]);
1207 kn = *knp;
1208 while (kn != NULL) {
1209 kn0 = SLIST_NEXT(kn, kn_link);
1210 if (kq == kn->kn_kq) {
1211 kn->kn_fop->f_detach(kn);
1212 /* XXX non-fd release of kn->kn_ptr */
1213 pool_put(&knote_pool, kn);
1214 *knp = kn0;
1215 } else {
1216 knp = &SLIST_NEXT(kn, kn_link);
1217 }
1218 kn = kn0;
1219 }
1220 }
1221 }
1222 pool_put(&kqueue_pool, kq);
1223 fp->f_data = NULL;
1224
1225 return (0);
1226 }
1227
1228 /*
1229 * wakeup a kqueue
1230 */
1231 static void
1232 kqueue_wakeup(struct kqueue *kq)
1233 {
1234 int s;
1235
1236 s = splsched();
1237 simple_lock(&kq->kq_lock);
1238 if (kq->kq_state & KQ_SLEEP) { /* if currently sleeping ... */
1239 kq->kq_state &= ~KQ_SLEEP;
1240 wakeup(kq); /* ... wakeup */
1241 }
1242
1243 /* Notify select/poll and kevent. */
1244 selnotify(&kq->kq_sel, 0);
1245 simple_unlock(&kq->kq_lock);
1246 splx(s);
1247 }
1248
1249 /*
1250 * struct fileops kqfilter method for a kqueue descriptor.
1251 * Event triggered when monitored kqueue changes.
1252 */
1253 /*ARGSUSED*/
1254 static int
1255 kqueue_kqfilter(struct file *fp, struct knote *kn)
1256 {
1257 struct kqueue *kq;
1258
1259 KASSERT(fp == kn->kn_fp);
1260 kq = (struct kqueue *)kn->kn_fp->f_data;
1261 if (kn->kn_filter != EVFILT_READ)
1262 return (1);
1263 kn->kn_fop = &kqread_filtops;
1264 SLIST_INSERT_HEAD(&kq->kq_sel.sel_klist, kn, kn_selnext);
1265 return (0);
1266 }
1267
1268
1269 /*
1270 * Walk down a list of knotes, activating them if their event has triggered.
1271 */
1272 void
1273 knote(struct klist *list, long hint)
1274 {
1275 struct knote *kn;
1276
1277 SLIST_FOREACH(kn, list, kn_selnext)
1278 if (kn->kn_fop->f_event(kn, hint))
1279 KNOTE_ACTIVATE(kn);
1280 }
1281
1282 /*
1283 * Remove all knotes from a specified klist
1284 */
1285 void
1286 knote_remove(struct proc *p, struct klist *list)
1287 {
1288 struct knote *kn;
1289
1290 while ((kn = SLIST_FIRST(list)) != NULL) {
1291 kn->kn_fop->f_detach(kn);
1292 knote_drop(kn, p, p->p_fd);
1293 }
1294 }
1295
1296 /*
1297 * Remove all knotes referencing a specified fd
1298 */
1299 void
1300 knote_fdclose(struct proc *p, int fd)
1301 {
1302 struct filedesc *fdp;
1303 struct klist *list;
1304
1305 fdp = p->p_fd;
1306 list = &fdp->fd_knlist[fd];
1307 knote_remove(p, list);
1308 }
1309
1310 /*
1311 * Attach a new knote to a file descriptor
1312 */
1313 static void
1314 knote_attach(struct knote *kn, struct filedesc *fdp)
1315 {
1316 struct klist *list;
1317 int size;
1318
1319 if (! kn->kn_fop->f_isfd) {
1320 /* if knote is not on an fd, store on internal hash table */
1321 if (fdp->fd_knhashmask == 0)
1322 fdp->fd_knhash = hashinit(KN_HASHSIZE, HASH_LIST,
1323 M_KEVENT, M_WAITOK, &fdp->fd_knhashmask);
1324 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
1325 goto done;
1326 }
1327
1328 /*
1329 * otherwise, knote is on an fd.
1330 * knotes are stored in fd_knlist indexed by kn->kn_id.
1331 */
1332 if (fdp->fd_knlistsize <= kn->kn_id) {
1333 /* expand list, it's too small */
1334 size = fdp->fd_knlistsize;
1335 while (size <= kn->kn_id) {
1336 /* grow in KQ_EXTENT chunks */
1337 size += KQ_EXTENT;
1338 }
1339 list = malloc(size * sizeof(struct klist *), M_KEVENT,M_WAITOK);
1340 if (fdp->fd_knlist) {
1341 /* copy existing knlist */
1342 memcpy((caddr_t)list, (caddr_t)fdp->fd_knlist,
1343 fdp->fd_knlistsize * sizeof(struct klist *));
1344 }
1345 /*
1346 * Zero new memory. Stylistically, SLIST_INIT() should be
1347 * used here, but that does same thing as the memset() anyway.
1348 */
1349 memset(&list[fdp->fd_knlistsize], 0,
1350 (size - fdp->fd_knlistsize) * sizeof(struct klist *));
1351
1352 /* switch to new knlist */
1353 if (fdp->fd_knlist != NULL)
1354 free(fdp->fd_knlist, M_KEVENT);
1355 fdp->fd_knlistsize = size;
1356 fdp->fd_knlist = list;
1357 }
1358
1359 /* get list head for this fd */
1360 list = &fdp->fd_knlist[kn->kn_id];
1361 done:
1362 /* add new knote */
1363 SLIST_INSERT_HEAD(list, kn, kn_link);
1364 kn->kn_status = 0;
1365 }
1366
1367 /*
1368 * Drop knote.
1369 * Should be called at spl == 0, since we don't want to hold spl
1370 * while calling FILE_UNUSE and free.
1371 */
1372 static void
1373 knote_drop(struct knote *kn, struct proc *p, struct filedesc *fdp)
1374 {
1375 struct klist *list;
1376
1377 if (kn->kn_fop->f_isfd)
1378 list = &fdp->fd_knlist[kn->kn_id];
1379 else
1380 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
1381
1382 SLIST_REMOVE(list, kn, knote, kn_link);
1383 if (kn->kn_status & KN_QUEUED)
1384 knote_dequeue(kn);
1385 if (kn->kn_fop->f_isfd)
1386 FILE_UNUSE(kn->kn_fp, p);
1387 pool_put(&knote_pool, kn);
1388 }
1389
1390
1391 /*
1392 * Queue new event for knote.
1393 */
1394 static void
1395 knote_enqueue(struct knote *kn)
1396 {
1397 struct kqueue *kq;
1398 int s;
1399
1400 kq = kn->kn_kq;
1401 KASSERT((kn->kn_status & KN_QUEUED) == 0);
1402
1403 s = splsched();
1404 simple_lock(&kq->kq_lock);
1405 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
1406 kn->kn_status |= KN_QUEUED;
1407 kq->kq_count++;
1408 simple_unlock(&kq->kq_lock);
1409 splx(s);
1410 kqueue_wakeup(kq);
1411 }
1412
1413 /*
1414 * Dequeue event for knote.
1415 */
1416 static void
1417 knote_dequeue(struct knote *kn)
1418 {
1419 struct kqueue *kq;
1420 int s;
1421
1422 KASSERT(kn->kn_status & KN_QUEUED);
1423 kq = kn->kn_kq;
1424
1425 s = splsched();
1426 simple_lock(&kq->kq_lock);
1427 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
1428 kn->kn_status &= ~KN_QUEUED;
1429 kq->kq_count--;
1430 simple_unlock(&kq->kq_lock);
1431 splx(s);
1432 }
Cache object: fb2a90088f6ec6f0825bd1d3514e3b9e
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