2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * $FreeBSD: src/sys/kern/kern_event.c,v 1.2.2.10 2004/04/04 07:03:14 cperciva Exp $
27 * $DragonFly: src/sys/kern/kern_event.c,v 1.33 2007/02/03 17:05:57 corecode Exp $
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kernel.h>
34 #include <sys/malloc.h>
35 #include <sys/unistd.h>
38 #include <sys/fcntl.h>
39 #include <sys/select.h>
40 #include <sys/queue.h>
41 #include <sys/event.h>
42 #include <sys/eventvar.h>
44 #include <sys/protosw.h>
45 #include <sys/socket.h>
46 #include <sys/socketvar.h>
48 #include <sys/sysctl.h>
49 #include <sys/sysproto.h>
51 #include <sys/signalvar.h>
52 #include <sys/filio.h>
54 #include <sys/thread2.h>
55 #include <sys/file2.h>
56 #include <sys/mplock2.h>
58 #include <vm/vm_zone.h>
60 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
62 static int kqueue_scan(struct file *fp, int maxevents,
63 struct kevent *ulistp, const struct timespec *timeout,
64 struct thread *td, int *res);
65 static int kqueue_read(struct file *fp, struct uio *uio,
66 struct ucred *cred, int flags);
67 static int kqueue_write(struct file *fp, struct uio *uio,
68 struct ucred *cred, int flags);
69 static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
70 struct ucred *cred, struct sysmsg *msg);
71 static int kqueue_poll(struct file *fp, int events, struct ucred *cred);
72 static int kqueue_kqfilter(struct file *fp, struct knote *kn);
73 static int kqueue_stat(struct file *fp, struct stat *st,
75 static int kqueue_close(struct file *fp);
76 static void kqueue_wakeup(struct kqueue *kq);
81 static struct fileops kqueueops = {
82 .fo_read = kqueue_read,
83 .fo_write = kqueue_write,
84 .fo_ioctl = kqueue_ioctl,
85 .fo_poll = kqueue_poll,
86 .fo_kqfilter = kqueue_kqfilter,
87 .fo_stat = kqueue_stat,
88 .fo_close = kqueue_close,
89 .fo_shutdown = nofo_shutdown
92 static void knote_attach(struct knote *kn, struct filedesc *fdp);
93 static void knote_drop(struct knote *kn, struct thread *td);
94 static void knote_enqueue(struct knote *kn);
95 static void knote_dequeue(struct knote *kn);
96 static void knote_init(void);
97 static struct knote *knote_alloc(void);
98 static void knote_free(struct knote *kn);
100 static void filt_kqdetach(struct knote *kn);
101 static int filt_kqueue(struct knote *kn, long hint);
102 static int filt_procattach(struct knote *kn);
103 static void filt_procdetach(struct knote *kn);
104 static int filt_proc(struct knote *kn, long hint);
105 static int filt_fileattach(struct knote *kn);
106 static void filt_timerexpire(void *knx);
107 static int filt_timerattach(struct knote *kn);
108 static void filt_timerdetach(struct knote *kn);
109 static int filt_timer(struct knote *kn, long hint);
111 static struct filterops file_filtops =
112 { 1, filt_fileattach, NULL, NULL };
113 static struct filterops kqread_filtops =
114 { 1, NULL, filt_kqdetach, filt_kqueue };
115 static struct filterops proc_filtops =
116 { 0, filt_procattach, filt_procdetach, filt_proc };
117 static struct filterops timer_filtops =
118 { 0, filt_timerattach, filt_timerdetach, filt_timer };
120 static vm_zone_t knote_zone;
121 static int kq_ncallouts = 0;
122 static int kq_calloutmax = (4 * 1024);
123 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
124 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
126 #define KNOTE_ACTIVATE(kn) do { \
127 kn->kn_status |= KN_ACTIVE; \
128 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
132 #define KN_HASHSIZE 64 /* XXX should be tunable */
133 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
135 extern struct filterops aio_filtops;
136 extern struct filterops sig_filtops;
139 * Table for for all system-defined filters.
141 static struct filterops *sysfilt_ops[] = {
142 &file_filtops, /* EVFILT_READ */
143 &file_filtops, /* EVFILT_WRITE */
144 &aio_filtops, /* EVFILT_AIO */
145 &file_filtops, /* EVFILT_VNODE */
146 &proc_filtops, /* EVFILT_PROC */
147 &sig_filtops, /* EVFILT_SIGNAL */
148 &timer_filtops, /* EVFILT_TIMER */
152 filt_fileattach(struct knote *kn)
154 return (fo_kqfilter(kn->kn_fp, kn));
158 * MPALMOSTSAFE - acquires mplock
161 kqueue_kqfilter(struct file *fp, struct knote *kn)
163 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
166 if (kn->kn_filter != EVFILT_READ) {
171 kn->kn_fop = &kqread_filtops;
172 SLIST_INSERT_HEAD(&kq->kq_sel.si_note, kn, kn_selnext);
178 filt_kqdetach(struct knote *kn)
180 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
182 SLIST_REMOVE(&kq->kq_sel.si_note, kn, knote, kn_selnext);
187 filt_kqueue(struct knote *kn, long hint)
189 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
191 kn->kn_data = kq->kq_count;
192 return (kn->kn_data > 0);
196 filt_procattach(struct knote *kn)
202 p = pfind(kn->kn_id);
203 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
204 p = zpfind(kn->kn_id);
209 if (!PRISON_CHECK(curthread->td_ucred, p->p_ucred))
212 kn->kn_ptr.p_proc = p;
213 kn->kn_flags |= EV_CLEAR; /* automatically set */
216 * internal flag indicating registration done by kernel
218 if (kn->kn_flags & EV_FLAG1) {
219 kn->kn_data = kn->kn_sdata; /* ppid */
220 kn->kn_fflags = NOTE_CHILD;
221 kn->kn_flags &= ~EV_FLAG1;
224 /* XXX lock the proc here while adding to the list? */
225 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
228 * Immediately activate any exit notes if the target process is a
229 * zombie. This is necessary to handle the case where the target
230 * process, e.g. a child, dies before the kevent is registered.
232 if (immediate && filt_proc(kn, NOTE_EXIT))
239 * The knote may be attached to a different process, which may exit,
240 * leaving nothing for the knote to be attached to. So when the process
241 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
242 * it will be deleted when read out. However, as part of the knote deletion,
243 * this routine is called, so a check is needed to avoid actually performing
244 * a detach, because the original process does not exist any more.
247 filt_procdetach(struct knote *kn)
251 if (kn->kn_status & KN_DETACHED)
253 /* XXX locking? this might modify another process. */
254 p = kn->kn_ptr.p_proc;
255 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
259 filt_proc(struct knote *kn, long hint)
264 * mask off extra data
266 event = (u_int)hint & NOTE_PCTRLMASK;
269 * if the user is interested in this event, record it.
271 if (kn->kn_sfflags & event)
272 kn->kn_fflags |= event;
275 * Process is gone, so flag the event as finished. Detach the
276 * knote from the process now because the process will be poof,
279 if (event == NOTE_EXIT) {
280 struct proc *p = kn->kn_ptr.p_proc;
281 if ((kn->kn_status & KN_DETACHED) == 0) {
282 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
283 kn->kn_status |= KN_DETACHED;
284 kn->kn_data = p->p_xstat;
285 kn->kn_ptr.p_proc = NULL;
287 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
292 * process forked, and user wants to track the new process,
293 * so attach a new knote to it, and immediately report an
294 * event with the parent's pid.
296 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
301 * register knote with new process.
303 kev.ident = hint & NOTE_PDATAMASK; /* pid */
304 kev.filter = kn->kn_filter;
305 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
306 kev.fflags = kn->kn_sfflags;
307 kev.data = kn->kn_id; /* parent */
308 kev.udata = kn->kn_kevent.udata; /* preserve udata */
309 error = kqueue_register(kn->kn_kq, &kev, NULL);
311 kn->kn_fflags |= NOTE_TRACKERR;
314 return (kn->kn_fflags != 0);
318 filt_timerexpire(void *knx)
320 struct knote *kn = knx;
321 struct callout *calloutp;
328 if ((kn->kn_flags & EV_ONESHOT) == 0) {
329 tv.tv_sec = kn->kn_sdata / 1000;
330 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
331 tticks = tvtohz_high(&tv);
332 calloutp = (struct callout *)kn->kn_hook;
333 callout_reset(calloutp, tticks, filt_timerexpire, kn);
338 * data contains amount of time to sleep, in milliseconds
341 filt_timerattach(struct knote *kn)
343 struct callout *calloutp;
347 if (kq_ncallouts >= kq_calloutmax)
351 tv.tv_sec = kn->kn_sdata / 1000;
352 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
353 tticks = tvtohz_high(&tv);
355 kn->kn_flags |= EV_CLEAR; /* automatically set */
356 MALLOC(calloutp, struct callout *, sizeof(*calloutp),
358 callout_init(calloutp);
359 kn->kn_hook = (caddr_t)calloutp;
360 callout_reset(calloutp, tticks, filt_timerexpire, kn);
366 filt_timerdetach(struct knote *kn)
368 struct callout *calloutp;
370 calloutp = (struct callout *)kn->kn_hook;
371 callout_stop(calloutp);
372 FREE(calloutp, M_KQUEUE);
377 filt_timer(struct knote *kn, long hint)
380 return (kn->kn_data != 0);
387 sys_kqueue(struct kqueue_args *uap)
389 struct thread *td = curthread;
394 error = falloc(td->td_lwp, &fp, &fd);
397 fp->f_flag = FREAD | FWRITE;
398 fp->f_type = DTYPE_KQUEUE;
399 fp->f_ops = &kqueueops;
401 kq = kmalloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO);
402 TAILQ_INIT(&kq->kq_head);
403 kq->kq_fdp = td->td_proc->p_fd;
406 fsetfd(kq->kq_fdp, fp, fd);
407 uap->sysmsg_result = fd;
416 sys_kevent(struct kevent_args *uap)
418 struct thread *td = curthread;
419 struct proc *p = td->td_proc;
422 struct file *fp = NULL;
424 int i, n, nerrors, error;
426 fp = holdfp(p->p_fd, uap->fd, -1);
429 if (fp->f_type != DTYPE_KQUEUE) {
434 if (uap->timeout != NULL) {
435 error = copyin(uap->timeout, &ts, sizeof(ts));
441 kq = (struct kqueue *)fp->f_data;
445 while (uap->nchanges > 0) {
446 n = uap->nchanges > KQ_NEVENTS ? KQ_NEVENTS : uap->nchanges;
447 error = copyin(uap->changelist, kq->kq_kev,
448 n * sizeof(struct kevent));
451 for (i = 0; i < n; i++) {
452 kevp = &kq->kq_kev[i];
453 kevp->flags &= ~EV_SYSFLAGS;
454 error = kqueue_register(kq, kevp, td);
456 if (uap->nevents != 0) {
457 kevp->flags = EV_ERROR;
459 (void) copyout((caddr_t)kevp,
460 (caddr_t)uap->eventlist,
471 uap->changelist += n;
474 uap->sysmsg_result = nerrors;
479 error = kqueue_scan(fp, uap->nevents, uap->eventlist,
480 uap->timeout, td, &uap->sysmsg_result);
489 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td)
491 struct filedesc *fdp = kq->kq_fdp;
492 struct filterops *fops;
493 struct file *fp = NULL;
494 struct knote *kn = NULL;
497 if (kev->filter < 0) {
498 if (kev->filter + EVFILT_SYSCOUNT < 0)
500 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */
504 * filter attach routine is responsible for insuring that
505 * the identifier can be attached to it.
507 kprintf("unknown filter: %d\n", kev->filter);
512 /* validate descriptor */
513 fp = holdfp(fdp, kev->ident, -1);
517 if (kev->ident < fdp->fd_knlistsize) {
518 SLIST_FOREACH(kn, &fdp->fd_knlist[kev->ident], kn_link)
519 if (kq == kn->kn_kq &&
520 kev->filter == kn->kn_filter)
524 if (fdp->fd_knhashmask != 0) {
527 list = &fdp->fd_knhash[
528 KN_HASH((u_long)kev->ident, fdp->fd_knhashmask)];
529 SLIST_FOREACH(kn, list, kn_link)
530 if (kev->ident == kn->kn_id &&
532 kev->filter == kn->kn_filter)
537 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
543 * kn now contains the matching knote, or NULL if no match
545 if (kev->flags & EV_ADD) {
558 * apply reference count to knote structure, and
559 * do not release it at the end of this routine.
563 kn->kn_sfflags = kev->fflags;
564 kn->kn_sdata = kev->data;
567 kn->kn_kevent = *kev;
569 knote_attach(kn, fdp);
570 if ((error = fops->f_attach(kn)) != 0) {
576 * The user may change some filter values after the
577 * initial EV_ADD, but doing so will not reset any
578 * filter which have already been triggered.
580 kn->kn_sfflags = kev->fflags;
581 kn->kn_sdata = kev->data;
582 kn->kn_kevent.udata = kev->udata;
586 if (kn->kn_fop->f_event(kn, 0))
589 } else if (kev->flags & EV_DELETE) {
590 kn->kn_fop->f_detach(kn);
595 if ((kev->flags & EV_DISABLE) &&
596 ((kn->kn_status & KN_DISABLED) == 0)) {
598 kn->kn_status |= KN_DISABLED;
602 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
604 kn->kn_status &= ~KN_DISABLED;
605 if ((kn->kn_status & KN_ACTIVE) &&
606 ((kn->kn_status & KN_QUEUED) == 0))
618 kqueue_scan(struct file *fp, int maxevents, struct kevent *ulistp,
619 const struct timespec *tsp, struct thread *td, int *res)
621 struct kqueue *kq = (struct kqueue *)fp->f_data;
623 struct timeval atv, rtv, ttv;
624 struct knote *kn, marker;
625 int count, timeout, nkev = 0, error = 0;
632 TIMESPEC_TO_TIMEVAL(&atv, tsp);
633 if (itimerfix(&atv)) {
637 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
640 timeout = atv.tv_sec > 24 * 60 * 60 ?
641 24 * 60 * 60 * hz : tvtohz_high(&atv);
642 getmicrouptime(&rtv);
643 timevaladd(&atv, &rtv);
652 if (atv.tv_sec || atv.tv_usec) {
653 getmicrouptime(&rtv);
654 if (timevalcmp(&rtv, &atv, >=))
657 timevalsub(&ttv, &rtv);
658 timeout = ttv.tv_sec > 24 * 60 * 60 ?
659 24 * 60 * 60 * hz : tvtohz_high(&ttv);
665 if (kq->kq_count == 0) {
669 kq->kq_state |= KQ_SLEEP;
670 error = tsleep(kq, PCATCH, "kqread", timeout);
675 /* don't restart after signals... */
676 if (error == ERESTART)
678 else if (error == EWOULDBLOCK)
683 TAILQ_INSERT_TAIL(&kq->kq_head, &marker, kn_tqe);
685 kn = TAILQ_FIRST(&kq->kq_head);
686 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
689 if (count == maxevents)
693 if (kn->kn_status & KN_DISABLED) {
694 kn->kn_status &= ~KN_QUEUED;
698 if ((kn->kn_flags & EV_ONESHOT) == 0 &&
699 kn->kn_fop->f_event(kn, 0) == 0) {
700 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
704 *kevp = kn->kn_kevent;
707 if (kn->kn_flags & EV_ONESHOT) {
708 kn->kn_status &= ~KN_QUEUED;
711 kn->kn_fop->f_detach(kn);
714 } else if (kn->kn_flags & EV_CLEAR) {
717 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
720 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
723 if (nkev == KQ_NEVENTS) {
725 error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
726 sizeof(struct kevent) * nkev);
735 TAILQ_REMOVE(&kq->kq_head, &marker, kn_tqe);
739 error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
740 sizeof(struct kevent) * nkev);
741 *res = maxevents - count;
747 * This could be expanded to call kqueue_scan, if desired.
752 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
761 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
770 kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
771 struct ucred *cred, struct sysmsg *msg)
777 kq = (struct kqueue *)fp->f_data;
782 kq->kq_state |= KQ_ASYNC;
784 kq->kq_state &= ~KQ_ASYNC;
788 error = fsetown(*(int *)data, &kq->kq_sigio);
799 * MPALMOSTSAFE - acquires mplock
802 kqueue_poll(struct file *fp, int events, struct ucred *cred)
804 struct kqueue *kq = (struct kqueue *)fp->f_data;
809 if (events & (POLLIN | POLLRDNORM)) {
811 revents |= events & (POLLIN | POLLRDNORM);
813 selrecord(curthread, &kq->kq_sel);
814 kq->kq_state |= KQ_SEL;
826 kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred)
828 struct kqueue *kq = (struct kqueue *)fp->f_data;
830 bzero((void *)st, sizeof(*st));
831 st->st_size = kq->kq_count;
832 st->st_blksize = sizeof(struct kevent);
833 st->st_mode = S_IFIFO;
838 * MPALMOSTSAFE - acquires mplock
841 kqueue_close(struct file *fp)
843 struct thread *td = curthread;
844 struct proc *p = td->td_proc;
845 struct kqueue *kq = (struct kqueue *)fp->f_data;
846 struct filedesc *fdp;
847 struct knote **knp, *kn, *kn0;
853 for (i = 0; i < fdp->fd_knlistsize; i++) {
854 knp = &SLIST_FIRST(&fdp->fd_knlist[i]);
857 kn0 = SLIST_NEXT(kn, kn_link);
858 if (kq == kn->kn_kq) {
859 kn->kn_fop->f_detach(kn);
864 knp = &SLIST_NEXT(kn, kn_link);
869 if (fdp->fd_knhashmask != 0) {
870 for (i = 0; i < fdp->fd_knhashmask + 1; i++) {
871 knp = &SLIST_FIRST(&fdp->fd_knhash[i]);
874 kn0 = SLIST_NEXT(kn, kn_link);
875 if (kq == kn->kn_kq) {
876 kn->kn_fop->f_detach(kn);
877 /* XXX non-fd release of kn->kn_ptr */
881 knp = &SLIST_NEXT(kn, kn_link);
888 funsetown(kq->kq_sigio);
896 kqueue_wakeup(struct kqueue *kq)
898 if (kq->kq_state & KQ_SLEEP) {
899 kq->kq_state &= ~KQ_SLEEP;
902 if (kq->kq_state & KQ_SEL) {
903 kq->kq_state &= ~KQ_SEL;
904 selwakeup(&kq->kq_sel);
906 KNOTE(&kq->kq_sel.si_note, 0);
910 * walk down a list of knotes, activating them if their event has triggered.
913 knote(struct klist *list, long hint)
917 SLIST_FOREACH(kn, list, kn_selnext)
918 if (kn->kn_fop->f_event(kn, hint))
923 * remove all knotes from a specified klist
926 knote_remove(struct thread *td, struct klist *list)
930 while ((kn = SLIST_FIRST(list)) != NULL) {
931 kn->kn_fop->f_detach(kn);
937 * remove all knotes referencing a specified fd
940 knote_fdclose(struct proc *p, int fd)
942 struct filedesc *fdp = p->p_fd;
943 struct klist *list = &fdp->fd_knlist[fd];
944 /* Take any thread of p */
945 struct thread *td = FIRST_LWP_IN_PROC(p)->lwp_thread;
947 knote_remove(td, list);
951 knote_attach(struct knote *kn, struct filedesc *fdp)
956 if (! kn->kn_fop->f_isfd) {
957 if (fdp->fd_knhashmask == 0)
958 fdp->fd_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
959 &fdp->fd_knhashmask);
960 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
964 if (fdp->fd_knlistsize <= kn->kn_id) {
965 size = fdp->fd_knlistsize;
966 while (size <= kn->kn_id)
968 MALLOC(list, struct klist *,
969 size * sizeof(struct klist *), M_KQUEUE, M_WAITOK);
970 bcopy((caddr_t)fdp->fd_knlist, (caddr_t)list,
971 fdp->fd_knlistsize * sizeof(struct klist *));
972 bzero((caddr_t)list +
973 fdp->fd_knlistsize * sizeof(struct klist *),
974 (size - fdp->fd_knlistsize) * sizeof(struct klist *));
975 if (fdp->fd_knlist != NULL)
976 FREE(fdp->fd_knlist, M_KQUEUE);
977 fdp->fd_knlistsize = size;
978 fdp->fd_knlist = list;
980 list = &fdp->fd_knlist[kn->kn_id];
982 SLIST_INSERT_HEAD(list, kn, kn_link);
987 * should be called outside of a critical section, since we don't want to
988 * hold a critical section while calling fdrop and free.
991 knote_drop(struct knote *kn, struct thread *td)
993 struct filedesc *fdp;
996 KKASSERT(td->td_proc);
997 fdp = td->td_proc->p_fd;
998 if (kn->kn_fop->f_isfd)
999 list = &fdp->fd_knlist[kn->kn_id];
1001 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
1003 SLIST_REMOVE(list, kn, knote, kn_link);
1004 if (kn->kn_status & KN_QUEUED)
1006 if (kn->kn_fop->f_isfd)
1013 knote_enqueue(struct knote *kn)
1015 struct kqueue *kq = kn->kn_kq;
1018 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
1020 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
1021 kn->kn_status |= KN_QUEUED;
1025 * Send SIGIO on request (typically set up as a mailbox signal)
1027 if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1)
1028 pgsigio(kq->kq_sigio, SIGIO, 0);
1034 knote_dequeue(struct knote *kn)
1036 struct kqueue *kq = kn->kn_kq;
1038 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
1041 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
1042 kn->kn_status &= ~KN_QUEUED;
1050 knote_zone = zinit("KNOTE", sizeof(struct knote), 0, 0, 1);
1052 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL)
1054 static struct knote *
1057 return ((struct knote *)zalloc(knote_zone));
1061 knote_free(struct knote *kn)
1063 zfree(knote_zone, kn);