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 $
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/kernel.h>
33 #include <sys/malloc.h>
34 #include <sys/unistd.h>
37 #include <sys/fcntl.h>
38 #include <sys/queue.h>
39 #include <sys/event.h>
40 #include <sys/eventvar.h>
41 #include <sys/protosw.h>
42 #include <sys/socket.h>
43 #include <sys/socketvar.h>
45 #include <sys/sysctl.h>
46 #include <sys/sysproto.h>
47 #include <sys/thread.h>
49 #include <sys/signalvar.h>
50 #include <sys/filio.h>
53 #include <sys/thread2.h>
54 #include <sys/file2.h>
55 #include <sys/mplock2.h>
57 #define EVENT_REGISTER 1
58 #define EVENT_PROCESS 2
60 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
62 struct kevent_copyin_args {
63 struct kevent_args *ka;
67 #define KNOTE_CACHE_MAX 8
69 struct knote_cache_list {
70 struct klist knote_cache;
74 static int kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count,
75 struct knote *marker);
76 static int kqueue_read(struct file *fp, struct uio *uio,
77 struct ucred *cred, int flags);
78 static int kqueue_write(struct file *fp, struct uio *uio,
79 struct ucred *cred, int flags);
80 static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
81 struct ucred *cred, struct sysmsg *msg);
82 static int kqueue_kqfilter(struct file *fp, struct knote *kn);
83 static int kqueue_stat(struct file *fp, struct stat *st,
85 static int kqueue_close(struct file *fp);
86 static void kqueue_wakeup(struct kqueue *kq);
87 static int filter_attach(struct knote *kn);
88 static int filter_event(struct knote *kn, long hint);
93 static struct fileops kqueueops = {
94 .fo_read = kqueue_read,
95 .fo_write = kqueue_write,
96 .fo_ioctl = kqueue_ioctl,
97 .fo_kqfilter = kqueue_kqfilter,
98 .fo_stat = kqueue_stat,
99 .fo_close = kqueue_close,
100 .fo_shutdown = nofo_shutdown
103 static void knote_attach(struct knote *kn);
104 static void knote_drop(struct knote *kn);
105 static void knote_detach_and_drop(struct knote *kn);
106 static void knote_enqueue(struct knote *kn);
107 static void knote_dequeue(struct knote *kn);
108 static struct knote *knote_alloc(void);
109 static void knote_free(struct knote *kn);
111 static void precise_sleep_intr(systimer_t info, int in_ipi,
112 struct intrframe *frame);
113 static int precise_sleep(void *ident, int flags, const char *wmesg,
116 static void filt_kqdetach(struct knote *kn);
117 static int filt_kqueue(struct knote *kn, long hint);
118 static int filt_procattach(struct knote *kn);
119 static void filt_procdetach(struct knote *kn);
120 static int filt_proc(struct knote *kn, long hint);
121 static int filt_fileattach(struct knote *kn);
122 static void filt_timerexpire(void *knx);
123 static int filt_timerattach(struct knote *kn);
124 static void filt_timerdetach(struct knote *kn);
125 static int filt_timer(struct knote *kn, long hint);
126 static int filt_userattach(struct knote *kn);
127 static void filt_userdetach(struct knote *kn);
128 static int filt_user(struct knote *kn, long hint);
129 static void filt_usertouch(struct knote *kn, struct kevent *kev,
131 static int filt_fsattach(struct knote *kn);
132 static void filt_fsdetach(struct knote *kn);
133 static int filt_fs(struct knote *kn, long hint);
135 static struct filterops file_filtops =
136 { FILTEROP_ISFD | FILTEROP_MPSAFE, filt_fileattach, NULL, NULL };
137 static struct filterops kqread_filtops =
138 { FILTEROP_ISFD | FILTEROP_MPSAFE, NULL, filt_kqdetach, filt_kqueue };
139 static struct filterops proc_filtops =
140 { FILTEROP_MPSAFE, filt_procattach, filt_procdetach, filt_proc };
141 static struct filterops timer_filtops =
142 { FILTEROP_MPSAFE, filt_timerattach, filt_timerdetach, filt_timer };
143 static struct filterops user_filtops =
144 { FILTEROP_MPSAFE, filt_userattach, filt_userdetach, filt_user };
145 static struct filterops fs_filtops =
146 { FILTEROP_MPSAFE, filt_fsattach, filt_fsdetach, filt_fs };
148 static int kq_ncallouts = 0;
149 static int kq_calloutmax = (4 * 1024);
150 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
151 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
152 static int kq_checkloop = 1000000;
153 SYSCTL_INT(_kern, OID_AUTO, kq_checkloop, CTLFLAG_RW,
154 &kq_checkloop, 0, "Maximum number of loops for kqueue scan");
155 static int kq_sleep_threshold = 20000;
156 SYSCTL_INT(_kern, OID_AUTO, kq_sleep_threshold, CTLFLAG_RW,
157 &kq_sleep_threshold, 0, "Minimum sleep duration without busy-looping");
159 #define KNOTE_ACTIVATE(kn) do { \
160 kn->kn_status |= KN_ACTIVE; \
161 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
165 #define KN_HASHSIZE 64 /* XXX should be tunable */
166 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
168 extern struct filterops aio_filtops;
169 extern struct filterops sig_filtops;
172 * Table for for all system-defined filters.
174 static struct filterops *sysfilt_ops[] = {
175 &file_filtops, /* EVFILT_READ */
176 &file_filtops, /* EVFILT_WRITE */
177 &aio_filtops, /* EVFILT_AIO */
178 &file_filtops, /* EVFILT_VNODE */
179 &proc_filtops, /* EVFILT_PROC */
180 &sig_filtops, /* EVFILT_SIGNAL */
181 &timer_filtops, /* EVFILT_TIMER */
182 &file_filtops, /* EVFILT_EXCEPT */
183 &user_filtops, /* EVFILT_USER */
184 &fs_filtops, /* EVFILT_FS */
187 static struct knote_cache_list knote_cache_lists[MAXCPU];
190 * Acquire a knote, return non-zero on success, 0 on failure.
192 * If we cannot acquire the knote we sleep and return 0. The knote
193 * may be stale on return in this case and the caller must restart
194 * whatever loop they are in.
196 * Related kq token must be held.
199 knote_acquire(struct knote *kn)
201 if (kn->kn_status & KN_PROCESSING) {
202 kn->kn_status |= KN_WAITING | KN_REPROCESS;
203 tsleep(kn, 0, "kqepts", hz);
204 /* knote may be stale now */
207 kn->kn_status |= KN_PROCESSING;
212 * Release an acquired knote, clearing KN_PROCESSING and handling any
213 * KN_REPROCESS events.
215 * Caller must be holding the related kq token
217 * Non-zero is returned if the knote is destroyed or detached.
220 knote_release(struct knote *kn)
224 while (kn->kn_status & KN_REPROCESS) {
225 kn->kn_status &= ~KN_REPROCESS;
226 if (kn->kn_status & KN_WAITING) {
227 kn->kn_status &= ~KN_WAITING;
230 if (kn->kn_status & KN_DELETING) {
231 knote_detach_and_drop(kn);
235 if (filter_event(kn, 0))
238 if (kn->kn_status & KN_DETACHED)
242 kn->kn_status &= ~KN_PROCESSING;
243 /* kn should not be accessed anymore */
248 filt_fileattach(struct knote *kn)
250 return (fo_kqfilter(kn->kn_fp, kn));
257 kqueue_kqfilter(struct file *fp, struct knote *kn)
259 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
261 if (kn->kn_filter != EVFILT_READ)
264 kn->kn_fop = &kqread_filtops;
265 knote_insert(&kq->kq_kqinfo.ki_note, kn);
270 filt_kqdetach(struct knote *kn)
272 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
274 knote_remove(&kq->kq_kqinfo.ki_note, kn);
279 filt_kqueue(struct knote *kn, long hint)
281 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
283 kn->kn_data = kq->kq_count;
284 return (kn->kn_data > 0);
288 filt_procattach(struct knote *kn)
294 p = pfind(kn->kn_id);
295 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
296 p = zpfind(kn->kn_id);
302 if (!PRISON_CHECK(curthread->td_ucred, p->p_ucred)) {
308 lwkt_gettoken(&p->p_token);
309 kn->kn_ptr.p_proc = p;
310 kn->kn_flags |= EV_CLEAR; /* automatically set */
313 * internal flag indicating registration done by kernel
315 if (kn->kn_flags & EV_FLAG1) {
316 kn->kn_data = kn->kn_sdata; /* ppid */
317 kn->kn_fflags = NOTE_CHILD;
318 kn->kn_flags &= ~EV_FLAG1;
321 knote_insert(&p->p_klist, kn);
324 * Immediately activate any exit notes if the target process is a
325 * zombie. This is necessary to handle the case where the target
326 * process, e.g. a child, dies before the kevent is negistered.
328 if (immediate && filt_proc(kn, NOTE_EXIT))
330 lwkt_reltoken(&p->p_token);
337 * The knote may be attached to a different process, which may exit,
338 * leaving nothing for the knote to be attached to. So when the process
339 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
340 * it will be deleted when read out. However, as part of the knote deletion,
341 * this routine is called, so a check is needed to avoid actually performing
342 * a detach, because the original process does not exist any more.
345 filt_procdetach(struct knote *kn)
349 if (kn->kn_status & KN_DETACHED)
351 p = kn->kn_ptr.p_proc;
352 knote_remove(&p->p_klist, kn);
356 filt_proc(struct knote *kn, long hint)
361 * mask off extra data
363 event = (u_int)hint & NOTE_PCTRLMASK;
366 * if the user is interested in this event, record it.
368 if (kn->kn_sfflags & event)
369 kn->kn_fflags |= event;
372 * Process is gone, so flag the event as finished. Detach the
373 * knote from the process now because the process will be poof,
376 if (event == NOTE_EXIT) {
377 struct proc *p = kn->kn_ptr.p_proc;
378 if ((kn->kn_status & KN_DETACHED) == 0) {
380 knote_remove(&p->p_klist, kn);
381 kn->kn_status |= KN_DETACHED;
382 kn->kn_data = p->p_xstat;
383 kn->kn_ptr.p_proc = NULL;
386 kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT);
391 * process forked, and user wants to track the new process,
392 * so attach a new knote to it, and immediately report an
393 * event with the parent's pid.
395 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
400 * register knote with new process.
402 kev.ident = hint & NOTE_PDATAMASK; /* pid */
403 kev.filter = kn->kn_filter;
404 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
405 kev.fflags = kn->kn_sfflags;
406 kev.data = kn->kn_id; /* parent */
407 kev.udata = kn->kn_kevent.udata; /* preserve udata */
408 error = kqueue_register(kn->kn_kq, &kev);
410 kn->kn_fflags |= NOTE_TRACKERR;
413 return (kn->kn_fflags != 0);
417 filt_timerreset(struct knote *kn)
419 struct callout *calloutp;
423 tv.tv_sec = kn->kn_sdata / 1000;
424 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
425 tticks = tvtohz_high(&tv);
426 calloutp = (struct callout *)kn->kn_hook;
427 callout_reset(calloutp, tticks, filt_timerexpire, kn);
431 * The callout interlocks with callout_terminate() but can still
432 * race a deletion so if KN_DELETING is set we just don't touch
436 filt_timerexpire(void *knx)
438 struct knote *kn = knx;
439 struct kqueue *kq = kn->kn_kq;
441 lwkt_getpooltoken(kq);
444 * Open knote_acquire(), since we can't sleep in callout,
445 * however, we do need to record this expiration.
448 if (kn->kn_status & KN_PROCESSING) {
449 kn->kn_status |= KN_REPROCESS;
450 if ((kn->kn_status & KN_DELETING) == 0 &&
451 (kn->kn_flags & EV_ONESHOT) == 0)
453 lwkt_relpooltoken(kq);
456 KASSERT((kn->kn_status & KN_DELETING) == 0,
457 ("acquire a deleting knote %#x", kn->kn_status));
458 kn->kn_status |= KN_PROCESSING;
461 if ((kn->kn_flags & EV_ONESHOT) == 0)
466 lwkt_relpooltoken(kq);
470 * data contains amount of time to sleep, in milliseconds
473 filt_timerattach(struct knote *kn)
475 struct callout *calloutp;
478 prev_ncallouts = atomic_fetchadd_int(&kq_ncallouts, 1);
479 if (prev_ncallouts >= kq_calloutmax) {
480 atomic_subtract_int(&kq_ncallouts, 1);
485 kn->kn_flags |= EV_CLEAR; /* automatically set */
486 calloutp = kmalloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK);
487 callout_init_mp(calloutp);
488 kn->kn_hook = (caddr_t)calloutp;
495 * This function is called with the knote flagged locked but it is
496 * still possible to race a callout event due to the callback blocking.
497 * We must call callout_terminate() instead of callout_stop() to deal
501 filt_timerdetach(struct knote *kn)
503 struct callout *calloutp;
505 calloutp = (struct callout *)kn->kn_hook;
506 callout_terminate(calloutp);
507 kfree(calloutp, M_KQUEUE);
508 atomic_subtract_int(&kq_ncallouts, 1);
512 filt_timer(struct knote *kn, long hint)
515 return (kn->kn_data != 0);
522 filt_userattach(struct knote *kn)
525 if (kn->kn_fflags & NOTE_TRIGGER)
526 kn->kn_ptr.hookid = 1;
528 kn->kn_ptr.hookid = 0;
533 filt_userdetach(struct knote *kn)
539 filt_user(struct knote *kn, long hint)
541 return (kn->kn_ptr.hookid);
545 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
551 if (kev->fflags & NOTE_TRIGGER)
552 kn->kn_ptr.hookid = 1;
554 ffctrl = kev->fflags & NOTE_FFCTRLMASK;
555 kev->fflags &= NOTE_FFLAGSMASK;
561 kn->kn_sfflags &= kev->fflags;
565 kn->kn_sfflags |= kev->fflags;
569 kn->kn_sfflags = kev->fflags;
573 /* XXX Return error? */
576 kn->kn_sdata = kev->data;
579 * This is not the correct use of EV_CLEAR in an event
580 * modification, it should have been passed as a NOTE instead.
581 * But we need to maintain compatibility with Apple & FreeBSD.
583 * Note however that EV_CLEAR can still be used when doing
584 * the initial registration of the event and works as expected
585 * (clears the event on reception).
587 if (kev->flags & EV_CLEAR) {
588 kn->kn_ptr.hookid = 0;
595 *kev = kn->kn_kevent;
596 kev->fflags = kn->kn_sfflags;
597 kev->data = kn->kn_sdata;
598 if (kn->kn_flags & EV_CLEAR) {
599 kn->kn_ptr.hookid = 0;
600 /* kn_data, kn_fflags handled by parent */
605 panic("filt_usertouch() - invalid type (%ld)", type);
613 struct klist fs_klist = SLIST_HEAD_INITIALIZER(&fs_klist);
616 filt_fsattach(struct knote *kn)
618 kn->kn_flags |= EV_CLEAR;
619 knote_insert(&fs_klist, kn);
625 filt_fsdetach(struct knote *kn)
627 knote_remove(&fs_klist, kn);
631 filt_fs(struct knote *kn, long hint)
633 kn->kn_fflags |= hint;
634 return (kn->kn_fflags != 0);
638 * Initialize a kqueue.
640 * NOTE: The lwp/proc code initializes a kqueue for select/poll ops.
645 kqueue_init(struct kqueue *kq, struct filedesc *fdp)
647 TAILQ_INIT(&kq->kq_knpend);
648 TAILQ_INIT(&kq->kq_knlist);
651 SLIST_INIT(&kq->kq_kqinfo.ki_note);
655 * Terminate a kqueue. Freeing the actual kq itself is left up to the
656 * caller (it might be embedded in a lwp so we don't do it here).
658 * The kq's knlist must be completely eradicated so block on any
662 kqueue_terminate(struct kqueue *kq)
666 lwkt_getpooltoken(kq);
667 while ((kn = TAILQ_FIRST(&kq->kq_knlist)) != NULL) {
668 if (knote_acquire(kn))
669 knote_detach_and_drop(kn);
671 lwkt_relpooltoken(kq);
674 hashdestroy(kq->kq_knhash, M_KQUEUE, kq->kq_knhashmask);
675 kq->kq_knhash = NULL;
676 kq->kq_knhashmask = 0;
684 sys_kqueue(struct kqueue_args *uap)
686 struct thread *td = curthread;
691 error = falloc(td->td_lwp, &fp, &fd);
694 fp->f_flag = FREAD | FWRITE;
695 fp->f_type = DTYPE_KQUEUE;
696 fp->f_ops = &kqueueops;
698 kq = kmalloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO);
699 kqueue_init(kq, td->td_proc->p_fd);
702 fsetfd(kq->kq_fdp, fp, fd);
703 uap->sysmsg_result = fd;
709 * Copy 'count' items into the destination list pointed to by uap->eventlist.
712 kevent_copyout(void *arg, struct kevent *kevp, int count, int *res)
714 struct kevent_copyin_args *kap;
717 kap = (struct kevent_copyin_args *)arg;
719 error = copyout(kevp, kap->ka->eventlist, count * sizeof(*kevp));
721 kap->ka->eventlist += count;
731 * Copy at most 'max' items from the list pointed to by kap->changelist,
732 * return number of items in 'events'.
735 kevent_copyin(void *arg, struct kevent *kevp, int max, int *events)
737 struct kevent_copyin_args *kap;
740 kap = (struct kevent_copyin_args *)arg;
742 count = min(kap->ka->nchanges - kap->pchanges, max);
743 error = copyin(kap->ka->changelist, kevp, count * sizeof *kevp);
745 kap->ka->changelist += count;
746 kap->pchanges += count;
757 kern_kevent(struct kqueue *kq, int nevents, int *res, void *uap,
758 k_copyin_fn kevent_copyinfn, k_copyout_fn kevent_copyoutfn,
759 struct timespec *tsp_in, int flags)
762 struct timespec *tsp, ats;
763 int i, n, total, error, nerrors = 0;
765 int limit = kq_checkloop;
766 struct kevent kev[KQ_NEVENTS];
768 struct lwkt_token *tok;
770 if (tsp_in == NULL || tsp_in->tv_sec || tsp_in->tv_nsec)
771 atomic_set_int(&curthread->td_mpflags, TDF_MP_BATCH_DEMARC);
778 error = kevent_copyinfn(uap, kev, KQ_NEVENTS, &n);
783 for (i = 0; i < n; i++) {
785 kevp->flags &= ~EV_SYSFLAGS;
786 error = kqueue_register(kq, kevp);
789 * If a registration returns an error we
790 * immediately post the error. The kevent()
791 * call itself will fail with the error if
792 * no space is available for posting.
794 * Such errors normally bypass the timeout/blocking
795 * code. However, if the copyoutfn function refuses
796 * to post the error (see sys_poll()), then we
799 if (error || (kevp->flags & EV_RECEIPT)) {
800 kevp->flags = EV_ERROR;
803 kevent_copyoutfn(uap, kevp, 1, res);
806 } else if (lres != *res) {
817 * Acquire/wait for events - setup timeout
820 if (tsp->tv_sec || tsp->tv_nsec) {
822 timespecadd(tsp, &ats); /* tsp = target time */
829 * Collect as many events as we can. Sleeping on successive
830 * loops is disabled if copyoutfn has incremented (*res).
832 * The loop stops if an error occurs, all events have been
833 * scanned (the marker has been reached), or fewer than the
834 * maximum number of events is found.
836 * The copyoutfn function does not have to increment (*res) in
837 * order for the loop to continue.
839 * NOTE: doselect() usually passes 0x7FFFFFFF for nevents.
843 marker.kn_filter = EVFILT_MARKER;
844 marker.kn_status = KN_PROCESSING;
845 tok = lwkt_token_pool_lookup(kq);
847 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe);
849 while ((n = nevents - total) > 0) {
854 * If no events are pending sleep until timeout (if any)
855 * or an event occurs.
857 * After the sleep completes the marker is moved to the
858 * end of the list, making any received events available
861 if (kq->kq_count == 0 && *res == 0) {
862 int timeout, ustimeout = 0;
866 } else if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) {
870 struct timespec atx = *tsp;
873 timespecsub(&atx, &ats);
874 if (atx.tv_sec < 0) {
878 timeout = atx.tv_sec > 24 * 60 * 60 ?
882 if (flags & KEVENT_TIMEOUT_PRECISE &&
884 if (atx.tv_sec == 0 &&
885 atx.tv_nsec < kq_sleep_threshold) {
886 DELAY(atx.tv_nsec / 1000);
889 } else if (atx.tv_sec < 2000) {
890 ustimeout = atx.tv_sec *
891 1000000 + atx.tv_nsec/1000;
893 ustimeout = 2000000000;
899 if (kq->kq_count == 0) {
901 if (__predict_false(kq->kq_sleep_cnt == 0)) {
903 * Guard against possible wrapping. And
904 * set it to 2, so that kqueue_wakeup()
905 * can wake everyone up.
907 kq->kq_sleep_cnt = 2;
909 if ((flags & KEVENT_TIMEOUT_PRECISE) &&
911 error = precise_sleep(kq, PCATCH,
912 "kqread", ustimeout);
914 error = tsleep(kq, PCATCH, "kqread",
918 /* don't restart after signals... */
919 if (error == ERESTART)
926 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe);
927 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker,
934 * Process all received events
935 * Account for all non-spurious events in our total
937 i = kqueue_scan(kq, kev, n, &marker);
940 error = kevent_copyoutfn(uap, kev, i, res);
941 total += *res - lres;
945 if (limit && --limit == 0)
946 panic("kqueue: checkloop failed i=%d", i);
949 * Normally when fewer events are returned than requested
950 * we can stop. However, if only spurious events were
951 * collected the copyout will not bump (*res) and we have
958 * Deal with an edge case where spurious events can cause
959 * a loop to occur without moving the marker. This can
960 * prevent kqueue_scan() from picking up new events which
961 * race us. We must be sure to move the marker for this
964 * NOTE: We do not want to move the marker if events
965 * were scanned because normal kqueue operations
966 * may reactivate events. Moving the marker in
967 * that case could result in duplicates for the
972 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe);
973 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe);
978 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe);
981 /* Timeouts do not return EWOULDBLOCK. */
982 if (error == EWOULDBLOCK)
991 sys_kevent(struct kevent_args *uap)
993 struct thread *td = curthread;
994 struct proc *p = td->td_proc;
995 struct timespec ts, *tsp;
997 struct file *fp = NULL;
998 struct kevent_copyin_args *kap, ka;
1002 error = copyin(uap->timeout, &ts, sizeof(ts));
1009 fp = holdfp(p->p_fd, uap->fd, -1);
1012 if (fp->f_type != DTYPE_KQUEUE) {
1017 kq = (struct kqueue *)fp->f_data;
1023 error = kern_kevent(kq, uap->nevents, &uap->sysmsg_result, kap,
1024 kevent_copyin, kevent_copyout, tsp, 0);
1032 kqueue_register(struct kqueue *kq, struct kevent *kev)
1034 struct filedesc *fdp = kq->kq_fdp;
1035 struct klist *list = NULL;
1036 struct filterops *fops;
1037 struct file *fp = NULL;
1038 struct knote *kn = NULL;
1041 struct knote_cache_list *cache_list;
1043 if (kev->filter < 0) {
1044 if (kev->filter + EVFILT_SYSCOUNT < 0)
1046 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */
1050 * filter attach routine is responsible for insuring that
1051 * the identifier can be attached to it.
1056 if (fops->f_flags & FILTEROP_ISFD) {
1057 /* validate descriptor */
1058 fp = holdfp(fdp, kev->ident, -1);
1063 cache_list = &knote_cache_lists[mycpuid];
1064 if (SLIST_EMPTY(&cache_list->knote_cache)) {
1065 struct knote *new_kn;
1067 new_kn = knote_alloc();
1069 SLIST_INSERT_HEAD(&cache_list->knote_cache, new_kn, kn_link);
1070 cache_list->knote_cache_cnt++;
1075 lwkt_getpooltoken(kq);
1078 * Make sure that only one thread can register event on this kqueue,
1079 * so that we would not suffer any race, even if the registration
1080 * blocked, i.e. kq token was released, and the kqueue was shared
1081 * between threads (this should be rare though).
1083 while (__predict_false(kq->kq_regtd != NULL && kq->kq_regtd != td)) {
1084 kq->kq_state |= KQ_REGWAIT;
1085 tsleep(&kq->kq_regtd, 0, "kqreg", 0);
1087 if (__predict_false(kq->kq_regtd != NULL)) {
1088 /* Recursive calling of kqueue_register() */
1091 /* Owner of the kq_regtd, i.e. td != NULL */
1096 list = &fp->f_klist;
1097 } else if (kq->kq_knhashmask) {
1098 list = &kq->kq_knhash[
1099 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
1102 lwkt_getpooltoken(list);
1104 SLIST_FOREACH(kn, list, kn_link) {
1105 if (kn->kn_kq == kq &&
1106 kn->kn_filter == kev->filter &&
1107 kn->kn_id == kev->ident) {
1108 if (knote_acquire(kn) == 0)
1113 lwkt_relpooltoken(list);
1117 * NOTE: At this point if kn is non-NULL we will have acquired
1118 * it and set KN_PROCESSING.
1120 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
1126 * kn now contains the matching knote, or NULL if no match
1128 if (kev->flags & EV_ADD) {
1131 kn = SLIST_FIRST(&cache_list->knote_cache);
1136 SLIST_REMOVE_HEAD(&cache_list->knote_cache,
1138 cache_list->knote_cache_cnt--;
1146 * apply reference count to knote structure, and
1147 * do not release it at the end of this routine.
1151 kn->kn_sfflags = kev->fflags;
1152 kn->kn_sdata = kev->data;
1155 kn->kn_kevent = *kev;
1158 * KN_PROCESSING prevents the knote from getting
1159 * ripped out from under us while we are trying
1160 * to attach it, in case the attach blocks.
1162 kn->kn_status = KN_PROCESSING;
1164 if ((error = filter_attach(kn)) != 0) {
1165 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1171 * Interlock against close races which either tried
1172 * to remove our knote while we were blocked or missed
1173 * it entirely prior to our attachment. We do not
1174 * want to end up with a knote on a closed descriptor.
1176 if ((fops->f_flags & FILTEROP_ISFD) &&
1177 checkfdclosed(fdp, kev->ident, kn->kn_fp)) {
1178 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1182 * The user may change some filter values after the
1183 * initial EV_ADD, but doing so will not reset any
1184 * filter which have already been triggered.
1186 KKASSERT(kn->kn_status & KN_PROCESSING);
1187 if (fops == &user_filtops) {
1188 filt_usertouch(kn, kev, EVENT_REGISTER);
1190 kn->kn_sfflags = kev->fflags;
1191 kn->kn_sdata = kev->data;
1192 kn->kn_kevent.udata = kev->udata;
1197 * Execute the filter event to immediately activate the
1198 * knote if necessary. If reprocessing events are pending
1199 * due to blocking above we do not run the filter here
1200 * but instead let knote_release() do it. Otherwise we
1201 * might run the filter on a deleted event.
1203 if ((kn->kn_status & KN_REPROCESS) == 0) {
1204 if (filter_event(kn, 0))
1207 } else if (kev->flags & EV_DELETE) {
1209 * Delete the existing knote
1211 knote_detach_and_drop(kn);
1215 * Modify an existing event.
1217 * The user may change some filter values after the
1218 * initial EV_ADD, but doing so will not reset any
1219 * filter which have already been triggered.
1221 KKASSERT(kn->kn_status & KN_PROCESSING);
1222 if (fops == &user_filtops) {
1223 filt_usertouch(kn, kev, EVENT_REGISTER);
1225 kn->kn_sfflags = kev->fflags;
1226 kn->kn_sdata = kev->data;
1227 kn->kn_kevent.udata = kev->udata;
1231 * Execute the filter event to immediately activate the
1232 * knote if necessary. If reprocessing events are pending
1233 * due to blocking above we do not run the filter here
1234 * but instead let knote_release() do it. Otherwise we
1235 * might run the filter on a deleted event.
1237 if ((kn->kn_status & KN_REPROCESS) == 0) {
1238 if (filter_event(kn, 0))
1244 * Disablement does not deactivate a knote here.
1246 if ((kev->flags & EV_DISABLE) &&
1247 ((kn->kn_status & KN_DISABLED) == 0)) {
1248 kn->kn_status |= KN_DISABLED;
1252 * Re-enablement may have to immediately enqueue an active knote.
1254 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
1255 kn->kn_status &= ~KN_DISABLED;
1256 if ((kn->kn_status & KN_ACTIVE) &&
1257 ((kn->kn_status & KN_QUEUED) == 0)) {
1263 * Handle any required reprocessing
1266 /* kn may be invalid now */
1269 if (td != NULL) { /* Owner of the kq_regtd */
1270 kq->kq_regtd = NULL;
1271 if (__predict_false(kq->kq_state & KQ_REGWAIT)) {
1272 kq->kq_state &= ~KQ_REGWAIT;
1273 wakeup(&kq->kq_regtd);
1276 lwkt_relpooltoken(kq);
1283 * Scan the kqueue, return the number of active events placed in kevp up
1286 * Continuous mode events may get recycled, do not continue scanning past
1287 * marker unless no events have been collected.
1290 kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count,
1291 struct knote *marker)
1293 struct knote *kn, local_marker;
1297 local_marker.kn_filter = EVFILT_MARKER;
1298 local_marker.kn_status = KN_PROCESSING;
1300 lwkt_getpooltoken(kq);
1305 TAILQ_INSERT_HEAD(&kq->kq_knpend, &local_marker, kn_tqe);
1307 kn = TAILQ_NEXT(&local_marker, kn_tqe);
1308 if (kn->kn_filter == EVFILT_MARKER) {
1309 /* Marker reached, we are done */
1313 /* Move local marker past some other threads marker */
1314 kn = TAILQ_NEXT(kn, kn_tqe);
1315 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe);
1316 TAILQ_INSERT_BEFORE(kn, &local_marker, kn_tqe);
1321 * We can't skip a knote undergoing processing, otherwise
1322 * we risk not returning it when the user process expects
1323 * it should be returned. Sleep and retry.
1325 if (knote_acquire(kn) == 0)
1329 * Remove the event for processing.
1331 * WARNING! We must leave KN_QUEUED set to prevent the
1332 * event from being KNOTE_ACTIVATE()d while
1333 * the queue state is in limbo, in case we
1336 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe);
1340 * We have to deal with an extremely important race against
1341 * file descriptor close()s here. The file descriptor can
1342 * disappear MPSAFE, and there is a small window of
1343 * opportunity between that and the call to knote_fdclose().
1345 * If we hit that window here while doselect or dopoll is
1346 * trying to delete a spurious event they will not be able
1347 * to match up the event against a knote and will go haywire.
1349 if ((kn->kn_fop->f_flags & FILTEROP_ISFD) &&
1350 checkfdclosed(kq->kq_fdp, kn->kn_kevent.ident, kn->kn_fp)) {
1351 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1354 if (kn->kn_status & KN_DISABLED) {
1356 * If disabled we ensure the event is not queued
1357 * but leave its active bit set. On re-enablement
1358 * the event may be immediately triggered.
1360 kn->kn_status &= ~KN_QUEUED;
1361 } else if ((kn->kn_flags & EV_ONESHOT) == 0 &&
1362 (kn->kn_status & KN_DELETING) == 0 &&
1363 filter_event(kn, 0) == 0) {
1365 * If not running in one-shot mode and the event
1366 * is no longer present we ensure it is removed
1367 * from the queue and ignore it.
1369 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
1374 if (kn->kn_fop == &user_filtops)
1375 filt_usertouch(kn, kevp, EVENT_PROCESS);
1377 *kevp = kn->kn_kevent;
1382 if (kn->kn_flags & EV_ONESHOT) {
1383 kn->kn_status &= ~KN_QUEUED;
1384 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1386 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
1387 if (kn->kn_flags & EV_CLEAR) {
1391 if (kn->kn_flags & EV_DISPATCH) {
1392 kn->kn_status |= KN_DISABLED;
1394 kn->kn_status &= ~(KN_QUEUED |
1397 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe);
1404 * Handle any post-processing states
1408 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe);
1410 lwkt_relpooltoken(kq);
1416 * This could be expanded to call kqueue_scan, if desired.
1421 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
1430 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
1439 kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
1440 struct ucred *cred, struct sysmsg *msg)
1445 kq = (struct kqueue *)fp->f_data;
1446 lwkt_getpooltoken(kq);
1450 kq->kq_state |= KQ_ASYNC;
1452 kq->kq_state &= ~KQ_ASYNC;
1456 error = fsetown(*(int *)data, &kq->kq_sigio);
1462 lwkt_relpooltoken(kq);
1470 kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred)
1472 struct kqueue *kq = (struct kqueue *)fp->f_data;
1474 bzero((void *)st, sizeof(*st));
1475 st->st_size = kq->kq_count;
1476 st->st_blksize = sizeof(struct kevent);
1477 st->st_mode = S_IFIFO;
1485 kqueue_close(struct file *fp)
1487 struct kqueue *kq = (struct kqueue *)fp->f_data;
1489 kqueue_terminate(kq);
1492 funsetown(&kq->kq_sigio);
1494 kfree(kq, M_KQUEUE);
1499 kqueue_wakeup(struct kqueue *kq)
1501 if (kq->kq_sleep_cnt) {
1502 u_int sleep_cnt = kq->kq_sleep_cnt;
1504 kq->kq_sleep_cnt = 0;
1510 KNOTE(&kq->kq_kqinfo.ki_note, 0);
1514 * Calls filterops f_attach function, acquiring mplock if filter is not
1515 * marked as FILTEROP_MPSAFE.
1517 * Caller must be holding the related kq token
1520 filter_attach(struct knote *kn)
1524 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) {
1525 ret = kn->kn_fop->f_attach(kn);
1528 ret = kn->kn_fop->f_attach(kn);
1535 * Detach the knote and drop it, destroying the knote.
1537 * Calls filterops f_detach function, acquiring mplock if filter is not
1538 * marked as FILTEROP_MPSAFE.
1540 * Caller must be holding the related kq token
1543 knote_detach_and_drop(struct knote *kn)
1545 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1546 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) {
1547 kn->kn_fop->f_detach(kn);
1550 kn->kn_fop->f_detach(kn);
1557 * Calls filterops f_event function, acquiring mplock if filter is not
1558 * marked as FILTEROP_MPSAFE.
1560 * If the knote is in the middle of being created or deleted we cannot
1561 * safely call the filter op.
1563 * Caller must be holding the related kq token
1566 filter_event(struct knote *kn, long hint)
1570 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) {
1571 ret = kn->kn_fop->f_event(kn, hint);
1574 ret = kn->kn_fop->f_event(kn, hint);
1581 * Walk down a list of knotes, activating them if their event has triggered.
1583 * If we encounter any knotes which are undergoing processing we just mark
1584 * them for reprocessing and do not try to [re]activate the knote. However,
1585 * if a hint is being passed we have to wait and that makes things a bit
1589 knote(struct klist *list, long hint)
1593 struct knote *kntmp;
1595 lwkt_getpooltoken(list);
1597 SLIST_FOREACH(kn, list, kn_next) {
1599 lwkt_getpooltoken(kq);
1601 /* temporary verification hack */
1602 SLIST_FOREACH(kntmp, list, kn_next) {
1606 if (kn != kntmp || kn->kn_kq != kq) {
1607 lwkt_relpooltoken(kq);
1611 if (kn->kn_status & KN_PROCESSING) {
1613 * Someone else is processing the knote, ask the
1614 * other thread to reprocess it and don't mess
1615 * with it otherwise.
1618 kn->kn_status |= KN_REPROCESS;
1619 lwkt_relpooltoken(kq);
1624 * If the hint is non-zero we have to wait or risk
1625 * losing the state the caller is trying to update.
1627 * XXX This is a real problem, certain process
1628 * and signal filters will bump kn_data for
1629 * already-processed notes more than once if
1630 * we restart the list scan. FIXME.
1632 kn->kn_status |= KN_WAITING | KN_REPROCESS;
1633 tsleep(kn, 0, "knotec", hz);
1634 lwkt_relpooltoken(kq);
1639 * Become the reprocessing master ourselves.
1641 * If hint is non-zero running the event is mandatory
1642 * when not deleting so do it whether reprocessing is
1645 kn->kn_status |= KN_PROCESSING;
1646 if ((kn->kn_status & KN_DELETING) == 0) {
1647 if (filter_event(kn, hint))
1650 if (knote_release(kn)) {
1651 lwkt_relpooltoken(kq);
1654 lwkt_relpooltoken(kq);
1656 lwkt_relpooltoken(list);
1660 * Insert knote at head of klist.
1662 * This function may only be called via a filter function and thus
1663 * kq_token should already be held and marked for processing.
1666 knote_insert(struct klist *klist, struct knote *kn)
1668 lwkt_getpooltoken(klist);
1669 KKASSERT(kn->kn_status & KN_PROCESSING);
1670 SLIST_INSERT_HEAD(klist, kn, kn_next);
1671 lwkt_relpooltoken(klist);
1675 * Remove knote from a klist
1677 * This function may only be called via a filter function and thus
1678 * kq_token should already be held and marked for processing.
1681 knote_remove(struct klist *klist, struct knote *kn)
1683 lwkt_getpooltoken(klist);
1684 KKASSERT(kn->kn_status & KN_PROCESSING);
1685 SLIST_REMOVE(klist, kn, knote, kn_next);
1686 lwkt_relpooltoken(klist);
1690 knote_assume_knotes(struct kqinfo *src, struct kqinfo *dst,
1691 struct filterops *ops, void *hook)
1696 lwkt_getpooltoken(&src->ki_note);
1697 lwkt_getpooltoken(&dst->ki_note);
1698 while ((kn = SLIST_FIRST(&src->ki_note)) != NULL) {
1700 lwkt_getpooltoken(kq);
1701 if (SLIST_FIRST(&src->ki_note) != kn || kn->kn_kq != kq) {
1702 lwkt_relpooltoken(kq);
1705 if (knote_acquire(kn)) {
1706 knote_remove(&src->ki_note, kn);
1709 knote_insert(&dst->ki_note, kn);
1711 /* kn may be invalid now */
1713 lwkt_relpooltoken(kq);
1715 lwkt_relpooltoken(&dst->ki_note);
1716 lwkt_relpooltoken(&src->ki_note);
1720 * Remove all knotes referencing a specified fd
1723 knote_fdclose(struct file *fp, struct filedesc *fdp, int fd)
1727 struct knote *kntmp;
1729 lwkt_getpooltoken(&fp->f_klist);
1731 SLIST_FOREACH(kn, &fp->f_klist, kn_link) {
1732 if (kn->kn_kq->kq_fdp == fdp && kn->kn_id == fd) {
1734 lwkt_getpooltoken(kq);
1736 /* temporary verification hack */
1737 SLIST_FOREACH(kntmp, &fp->f_klist, kn_link) {
1741 if (kn != kntmp || kn->kn_kq->kq_fdp != fdp ||
1742 kn->kn_id != fd || kn->kn_kq != kq) {
1743 lwkt_relpooltoken(kq);
1746 if (knote_acquire(kn))
1747 knote_detach_and_drop(kn);
1748 lwkt_relpooltoken(kq);
1752 lwkt_relpooltoken(&fp->f_klist);
1756 * Low level attach function.
1758 * The knote should already be marked for processing.
1759 * Caller must hold the related kq token.
1762 knote_attach(struct knote *kn)
1765 struct kqueue *kq = kn->kn_kq;
1767 if (kn->kn_fop->f_flags & FILTEROP_ISFD) {
1768 KKASSERT(kn->kn_fp);
1769 list = &kn->kn_fp->f_klist;
1771 if (kq->kq_knhashmask == 0)
1772 kq->kq_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
1773 &kq->kq_knhashmask);
1774 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
1776 lwkt_getpooltoken(list);
1777 SLIST_INSERT_HEAD(list, kn, kn_link);
1778 lwkt_relpooltoken(list);
1779 TAILQ_INSERT_HEAD(&kq->kq_knlist, kn, kn_kqlink);
1783 * Low level drop function.
1785 * The knote should already be marked for processing.
1786 * Caller must hold the related kq token.
1789 knote_drop(struct knote *kn)
1796 if (kn->kn_fop->f_flags & FILTEROP_ISFD)
1797 list = &kn->kn_fp->f_klist;
1799 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
1801 lwkt_getpooltoken(list);
1802 SLIST_REMOVE(list, kn, knote, kn_link);
1803 lwkt_relpooltoken(list);
1804 TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink);
1805 if (kn->kn_status & KN_QUEUED)
1807 if (kn->kn_fop->f_flags & FILTEROP_ISFD) {
1815 * Low level enqueue function.
1817 * The knote should already be marked for processing.
1818 * Caller must be holding the kq token
1821 knote_enqueue(struct knote *kn)
1823 struct kqueue *kq = kn->kn_kq;
1825 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
1826 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe);
1827 kn->kn_status |= KN_QUEUED;
1831 * Send SIGIO on request (typically set up as a mailbox signal)
1833 if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1)
1834 pgsigio(kq->kq_sigio, SIGIO, 0);
1840 * Low level dequeue function.
1842 * The knote should already be marked for processing.
1843 * Caller must be holding the kq token
1846 knote_dequeue(struct knote *kn)
1848 struct kqueue *kq = kn->kn_kq;
1850 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
1851 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe);
1852 kn->kn_status &= ~KN_QUEUED;
1856 static struct knote *
1859 return kmalloc(sizeof(struct knote), M_KQUEUE, M_WAITOK);
1863 knote_free(struct knote *kn)
1865 struct knote_cache_list *cache_list;
1867 cache_list = &knote_cache_lists[mycpuid];
1868 if (cache_list->knote_cache_cnt < KNOTE_CACHE_MAX) {
1870 SLIST_INSERT_HEAD(&cache_list->knote_cache, kn, kn_link);
1871 cache_list->knote_cache_cnt++;
1875 kfree(kn, M_KQUEUE);
1884 precise_sleep_intr(systimer_t info, int in_ipi, struct intrframe *frame)
1886 struct sleepinfo *si;
1894 precise_sleep(void *ident, int flags, const char *wmesg, int us)
1896 struct systimer info;
1897 struct sleepinfo si = {
1903 tsleep_interlock(ident, flags);
1904 systimer_init_oneshot(&info, precise_sleep_intr, &si,
1906 r = tsleep(ident, flags | PINTERLOCKED, wmesg, 0);
1907 systimer_del(&info);