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
61 * Global token for kqueue subsystem
64 struct lwkt_token kq_token = LWKT_TOKEN_INITIALIZER(kq_token);
65 SYSCTL_LONG(_lwkt, OID_AUTO, kq_collisions,
66 CTLFLAG_RW, &kq_token.t_collisions, 0,
67 "Collision counter of kq_token");
70 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
72 struct kevent_copyin_args {
73 struct kevent_args *ka;
77 static int kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count,
78 struct knote *marker);
79 static int kqueue_read(struct file *fp, struct uio *uio,
80 struct ucred *cred, int flags);
81 static int kqueue_write(struct file *fp, struct uio *uio,
82 struct ucred *cred, int flags);
83 static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
84 struct ucred *cred, struct sysmsg *msg);
85 static int kqueue_kqfilter(struct file *fp, struct knote *kn);
86 static int kqueue_stat(struct file *fp, struct stat *st,
88 static int kqueue_close(struct file *fp);
89 static void kqueue_wakeup(struct kqueue *kq);
90 static int filter_attach(struct knote *kn);
91 static int filter_event(struct knote *kn, long hint);
96 static struct fileops kqueueops = {
97 .fo_read = kqueue_read,
98 .fo_write = kqueue_write,
99 .fo_ioctl = kqueue_ioctl,
100 .fo_kqfilter = kqueue_kqfilter,
101 .fo_stat = kqueue_stat,
102 .fo_close = kqueue_close,
103 .fo_shutdown = nofo_shutdown
106 static void knote_attach(struct knote *kn);
107 static void knote_drop(struct knote *kn);
108 static void knote_detach_and_drop(struct knote *kn);
109 static void knote_enqueue(struct knote *kn);
110 static void knote_dequeue(struct knote *kn);
111 static struct knote *knote_alloc(void);
112 static void knote_free(struct knote *kn);
114 static void filt_kqdetach(struct knote *kn);
115 static int filt_kqueue(struct knote *kn, long hint);
116 static int filt_procattach(struct knote *kn);
117 static void filt_procdetach(struct knote *kn);
118 static int filt_proc(struct knote *kn, long hint);
119 static int filt_fileattach(struct knote *kn);
120 static void filt_timerexpire(void *knx);
121 static int filt_timerattach(struct knote *kn);
122 static void filt_timerdetach(struct knote *kn);
123 static int filt_timer(struct knote *kn, long hint);
124 static int filt_userattach(struct knote *kn);
125 static void filt_userdetach(struct knote *kn);
126 static int filt_user(struct knote *kn, long hint);
127 static void filt_usertouch(struct knote *kn, struct kevent *kev,
130 static struct filterops file_filtops =
131 { FILTEROP_ISFD | FILTEROP_MPSAFE, filt_fileattach, NULL, NULL };
132 static struct filterops kqread_filtops =
133 { FILTEROP_ISFD | FILTEROP_MPSAFE, NULL, filt_kqdetach, filt_kqueue };
134 static struct filterops proc_filtops =
135 { 0, filt_procattach, filt_procdetach, filt_proc };
136 static struct filterops timer_filtops =
137 { FILTEROP_MPSAFE, filt_timerattach, filt_timerdetach, filt_timer };
138 static struct filterops user_filtops =
139 { 0, filt_userattach, filt_userdetach, filt_user };
141 static int kq_ncallouts = 0;
142 static int kq_calloutmax = (4 * 1024);
143 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
144 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
145 static int kq_checkloop = 1000000;
146 SYSCTL_INT(_kern, OID_AUTO, kq_checkloop, CTLFLAG_RW,
147 &kq_checkloop, 0, "Maximum number of loops for kqueue scan");
149 #define KNOTE_ACTIVATE(kn) do { \
150 kn->kn_status |= KN_ACTIVE; \
151 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
155 #define KN_HASHSIZE 64 /* XXX should be tunable */
156 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
158 extern struct filterops aio_filtops;
159 extern struct filterops sig_filtops;
162 * Table for for all system-defined filters.
164 static struct filterops *sysfilt_ops[] = {
165 &file_filtops, /* EVFILT_READ */
166 &file_filtops, /* EVFILT_WRITE */
167 &aio_filtops, /* EVFILT_AIO */
168 &file_filtops, /* EVFILT_VNODE */
169 &proc_filtops, /* EVFILT_PROC */
170 &sig_filtops, /* EVFILT_SIGNAL */
171 &timer_filtops, /* EVFILT_TIMER */
172 &file_filtops, /* EVFILT_EXCEPT */
173 &user_filtops, /* EVFILT_USER */
177 filt_fileattach(struct knote *kn)
179 return (fo_kqfilter(kn->kn_fp, kn));
186 kqueue_kqfilter(struct file *fp, struct knote *kn)
188 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
190 if (kn->kn_filter != EVFILT_READ)
193 kn->kn_fop = &kqread_filtops;
194 knote_insert(&kq->kq_kqinfo.ki_note, kn);
199 filt_kqdetach(struct knote *kn)
201 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
203 knote_remove(&kq->kq_kqinfo.ki_note, kn);
208 filt_kqueue(struct knote *kn, long hint)
210 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
212 kn->kn_data = kq->kq_count;
213 return (kn->kn_data > 0);
217 filt_procattach(struct knote *kn)
223 p = pfind(kn->kn_id);
224 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
225 p = zpfind(kn->kn_id);
231 if (!PRISON_CHECK(curthread->td_ucred, p->p_ucred)) {
237 lwkt_gettoken(&p->p_token);
238 kn->kn_ptr.p_proc = p;
239 kn->kn_flags |= EV_CLEAR; /* automatically set */
242 * internal flag indicating registration done by kernel
244 if (kn->kn_flags & EV_FLAG1) {
245 kn->kn_data = kn->kn_sdata; /* ppid */
246 kn->kn_fflags = NOTE_CHILD;
247 kn->kn_flags &= ~EV_FLAG1;
250 knote_insert(&p->p_klist, kn);
253 * Immediately activate any exit notes if the target process is a
254 * zombie. This is necessary to handle the case where the target
255 * process, e.g. a child, dies before the kevent is negistered.
257 if (immediate && filt_proc(kn, NOTE_EXIT))
259 lwkt_reltoken(&p->p_token);
266 * The knote may be attached to a different process, which may exit,
267 * leaving nothing for the knote to be attached to. So when the process
268 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
269 * it will be deleted when read out. However, as part of the knote deletion,
270 * this routine is called, so a check is needed to avoid actually performing
271 * a detach, because the original process does not exist any more.
274 filt_procdetach(struct knote *kn)
278 if (kn->kn_status & KN_DETACHED)
280 p = kn->kn_ptr.p_proc;
281 knote_remove(&p->p_klist, kn);
285 filt_proc(struct knote *kn, long hint)
290 * mask off extra data
292 event = (u_int)hint & NOTE_PCTRLMASK;
295 * if the user is interested in this event, record it.
297 if (kn->kn_sfflags & event)
298 kn->kn_fflags |= event;
301 * Process is gone, so flag the event as finished. Detach the
302 * knote from the process now because the process will be poof,
305 if (event == NOTE_EXIT) {
306 struct proc *p = kn->kn_ptr.p_proc;
307 if ((kn->kn_status & KN_DETACHED) == 0) {
309 knote_remove(&p->p_klist, kn);
310 kn->kn_status |= KN_DETACHED;
311 kn->kn_data = p->p_xstat;
312 kn->kn_ptr.p_proc = NULL;
315 kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT);
320 * process forked, and user wants to track the new process,
321 * so attach a new knote to it, and immediately report an
322 * event with the parent's pid.
324 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
329 * register knote with new process.
331 kev.ident = hint & NOTE_PDATAMASK; /* pid */
332 kev.filter = kn->kn_filter;
333 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
334 kev.fflags = kn->kn_sfflags;
335 kev.data = kn->kn_id; /* parent */
336 kev.udata = kn->kn_kevent.udata; /* preserve udata */
337 error = kqueue_register(kn->kn_kq, &kev);
339 kn->kn_fflags |= NOTE_TRACKERR;
342 return (kn->kn_fflags != 0);
346 * The callout interlocks with callout_terminate() but can still
347 * race a deletion so if KN_DELETING is set we just don't touch
351 filt_timerexpire(void *knx)
353 struct lwkt_token *tok;
354 struct knote *kn = knx;
355 struct callout *calloutp;
359 tok = lwkt_token_pool_lookup(kn->kn_kq);
361 if ((kn->kn_status & KN_DELETING) == 0) {
365 if ((kn->kn_flags & EV_ONESHOT) == 0) {
366 tv.tv_sec = kn->kn_sdata / 1000;
367 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
368 tticks = tvtohz_high(&tv);
369 calloutp = (struct callout *)kn->kn_hook;
370 callout_reset(calloutp, tticks, filt_timerexpire, kn);
377 * data contains amount of time to sleep, in milliseconds
380 filt_timerattach(struct knote *kn)
382 struct callout *calloutp;
387 prev_ncallouts = atomic_fetchadd_int(&kq_ncallouts, 1);
388 if (prev_ncallouts >= kq_calloutmax) {
389 atomic_subtract_int(&kq_ncallouts, 1);
394 tv.tv_sec = kn->kn_sdata / 1000;
395 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
396 tticks = tvtohz_high(&tv);
398 kn->kn_flags |= EV_CLEAR; /* automatically set */
399 calloutp = kmalloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK);
400 callout_init_mp(calloutp);
401 kn->kn_hook = (caddr_t)calloutp;
402 callout_reset(calloutp, tticks, filt_timerexpire, kn);
408 * This function is called with the knote flagged locked but it is
409 * still possible to race a callout event due to the callback blocking.
410 * We must call callout_terminate() instead of callout_stop() to deal
414 filt_timerdetach(struct knote *kn)
416 struct callout *calloutp;
418 calloutp = (struct callout *)kn->kn_hook;
419 callout_terminate(calloutp);
420 kfree(calloutp, M_KQUEUE);
421 atomic_subtract_int(&kq_ncallouts, 1);
425 filt_timer(struct knote *kn, long hint)
428 return (kn->kn_data != 0);
435 filt_userattach(struct knote *kn)
438 if (kn->kn_fflags & NOTE_TRIGGER)
439 kn->kn_ptr.hookid = 1;
441 kn->kn_ptr.hookid = 0;
446 * This function is called with the knote flagged locked but it is
447 * still possible to race a callout event due to the callback blocking.
448 * We must call callout_terminate() instead of callout_stop() to deal
452 filt_userdetach(struct knote *kn)
458 filt_user(struct knote *kn, long hint)
460 return (kn->kn_ptr.hookid);
464 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
470 if (kev->fflags & NOTE_TRIGGER)
471 kn->kn_ptr.hookid = 1;
473 ffctrl = kev->fflags & NOTE_FFCTRLMASK;
474 kev->fflags &= NOTE_FFLAGSMASK;
480 kn->kn_sfflags &= kev->fflags;
484 kn->kn_sfflags |= kev->fflags;
488 kn->kn_sfflags = kev->fflags;
492 /* XXX Return error? */
495 kn->kn_sdata = kev->data;
498 * This is not the correct use of EV_CLEAR in an event
499 * modification, it should have been passed as a NOTE instead.
500 * But we need to maintain compatibility with Apple & FreeBSD.
502 * Note however that EV_CLEAR can still be used when doing
503 * the initial registration of the event and works as expected
504 * (clears the event on reception).
506 if (kev->flags & EV_CLEAR) {
507 kn->kn_ptr.hookid = 0;
514 *kev = kn->kn_kevent;
515 kev->fflags = kn->kn_sfflags;
516 kev->data = kn->kn_sdata;
517 if (kn->kn_flags & EV_CLEAR) {
518 kn->kn_ptr.hookid = 0;
519 /* kn_data, kn_fflags handled by parent */
524 panic("filt_usertouch() - invalid type (%ld)", type);
530 * Acquire a knote, return non-zero on success, 0 on failure.
532 * If we cannot acquire the knote we sleep and return 0. The knote
533 * may be stale on return in this case and the caller must restart
534 * whatever loop they are in.
536 * Related kq token must be held.
539 knote_acquire(struct knote *kn)
541 if (kn->kn_status & KN_PROCESSING) {
542 kn->kn_status |= KN_WAITING | KN_REPROCESS;
543 tsleep(kn, 0, "kqepts", hz);
544 /* knote may be stale now */
547 kn->kn_status |= KN_PROCESSING;
552 * Release an acquired knote, clearing KN_PROCESSING and handling any
553 * KN_REPROCESS events.
555 * Caller must be holding the related kq token
557 * Non-zero is returned if the knote is destroyed or detached.
560 knote_release(struct knote *kn)
562 while (kn->kn_status & KN_REPROCESS) {
563 kn->kn_status &= ~KN_REPROCESS;
564 if (kn->kn_status & KN_WAITING) {
565 kn->kn_status &= ~KN_WAITING;
568 if (kn->kn_status & KN_DELETING) {
569 knote_detach_and_drop(kn);
573 if (filter_event(kn, 0))
576 kn->kn_status &= ~KN_PROCESSING;
577 if (kn->kn_status & KN_DETACHED)
584 * Initialize a kqueue.
586 * NOTE: The lwp/proc code initializes a kqueue for select/poll ops.
591 kqueue_init(struct kqueue *kq, struct filedesc *fdp)
593 TAILQ_INIT(&kq->kq_knpend);
594 TAILQ_INIT(&kq->kq_knlist);
597 SLIST_INIT(&kq->kq_kqinfo.ki_note);
601 * Terminate a kqueue. Freeing the actual kq itself is left up to the
602 * caller (it might be embedded in a lwp so we don't do it here).
604 * The kq's knlist must be completely eradicated so block on any
608 kqueue_terminate(struct kqueue *kq)
610 struct lwkt_token *tok;
613 tok = lwkt_token_pool_lookup(kq);
615 while ((kn = TAILQ_FIRST(&kq->kq_knlist)) != NULL) {
616 if (knote_acquire(kn))
617 knote_detach_and_drop(kn);
620 hashdestroy(kq->kq_knhash, M_KQUEUE, kq->kq_knhashmask);
621 kq->kq_knhash = NULL;
622 kq->kq_knhashmask = 0;
631 sys_kqueue(struct kqueue_args *uap)
633 struct thread *td = curthread;
638 error = falloc(td->td_lwp, &fp, &fd);
641 fp->f_flag = FREAD | FWRITE;
642 fp->f_type = DTYPE_KQUEUE;
643 fp->f_ops = &kqueueops;
645 kq = kmalloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO);
646 kqueue_init(kq, td->td_proc->p_fd);
649 fsetfd(kq->kq_fdp, fp, fd);
650 uap->sysmsg_result = fd;
656 * Copy 'count' items into the destination list pointed to by uap->eventlist.
659 kevent_copyout(void *arg, struct kevent *kevp, int count, int *res)
661 struct kevent_copyin_args *kap;
664 kap = (struct kevent_copyin_args *)arg;
666 error = copyout(kevp, kap->ka->eventlist, count * sizeof(*kevp));
668 kap->ka->eventlist += count;
678 * Copy at most 'max' items from the list pointed to by kap->changelist,
679 * return number of items in 'events'.
682 kevent_copyin(void *arg, struct kevent *kevp, int max, int *events)
684 struct kevent_copyin_args *kap;
687 kap = (struct kevent_copyin_args *)arg;
689 count = min(kap->ka->nchanges - kap->pchanges, max);
690 error = copyin(kap->ka->changelist, kevp, count * sizeof *kevp);
692 kap->ka->changelist += count;
693 kap->pchanges += count;
704 kern_kevent(struct kqueue *kq, int nevents, int *res, void *uap,
705 k_copyin_fn kevent_copyinfn, k_copyout_fn kevent_copyoutfn,
706 struct timespec *tsp_in)
709 struct timespec *tsp, ats;
710 int i, n, total, error, nerrors = 0;
712 int limit = kq_checkloop;
713 struct kevent kev[KQ_NEVENTS];
715 struct lwkt_token *tok;
717 if (tsp_in == NULL || tsp_in->tv_sec || tsp_in->tv_nsec)
718 atomic_set_int(&curthread->td_mpflags, TDF_MP_BATCH_DEMARC);
725 error = kevent_copyinfn(uap, kev, KQ_NEVENTS, &n);
730 for (i = 0; i < n; i++) {
732 kevp->flags &= ~EV_SYSFLAGS;
733 error = kqueue_register(kq, kevp);
736 * If a registration returns an error we
737 * immediately post the error. The kevent()
738 * call itself will fail with the error if
739 * no space is available for posting.
741 * Such errors normally bypass the timeout/blocking
742 * code. However, if the copyoutfn function refuses
743 * to post the error (see sys_poll()), then we
746 if (error || (kevp->flags & EV_RECEIPT)) {
747 kevp->flags = EV_ERROR;
750 kevent_copyoutfn(uap, kevp, 1, res);
753 } else if (lres != *res) {
764 * Acquire/wait for events - setup timeout
767 if (tsp->tv_sec || tsp->tv_nsec) {
769 timespecadd(tsp, &ats); /* tsp = target time */
776 * Collect as many events as we can. Sleeping on successive
777 * loops is disabled if copyoutfn has incremented (*res).
779 * The loop stops if an error occurs, all events have been
780 * scanned (the marker has been reached), or fewer than the
781 * maximum number of events is found.
783 * The copyoutfn function does not have to increment (*res) in
784 * order for the loop to continue.
786 * NOTE: doselect() usually passes 0x7FFFFFFF for nevents.
790 marker.kn_filter = EVFILT_MARKER;
791 marker.kn_status = KN_PROCESSING;
792 tok = lwkt_token_pool_lookup(kq);
794 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe);
796 while ((n = nevents - total) > 0) {
801 * If no events are pending sleep until timeout (if any)
802 * or an event occurs.
804 * After the sleep completes the marker is moved to the
805 * end of the list, making any received events available
808 if (kq->kq_count == 0 && *res == 0) {
813 } else if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) {
817 struct timespec atx = *tsp;
820 timespecsub(&atx, &ats);
821 if (atx.tv_sec < 0) {
825 timeout = atx.tv_sec > 24 * 60 * 60 ?
832 if (kq->kq_count == 0) {
833 kq->kq_state |= KQ_SLEEP;
834 error = tsleep(kq, PCATCH, "kqread", timeout);
836 /* don't restart after signals... */
837 if (error == ERESTART)
844 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe);
845 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker,
852 * Process all received events
853 * Account for all non-spurious events in our total
855 i = kqueue_scan(kq, kev, n, &marker);
858 error = kevent_copyoutfn(uap, kev, i, res);
859 total += *res - lres;
863 if (limit && --limit == 0)
864 panic("kqueue: checkloop failed i=%d", i);
867 * Normally when fewer events are returned than requested
868 * we can stop. However, if only spurious events were
869 * collected the copyout will not bump (*res) and we have
876 * Deal with an edge case where spurious events can cause
877 * a loop to occur without moving the marker. This can
878 * prevent kqueue_scan() from picking up new events which
879 * race us. We must be sure to move the marker for this
882 * NOTE: We do not want to move the marker if events
883 * were scanned because normal kqueue operations
884 * may reactivate events. Moving the marker in
885 * that case could result in duplicates for the
890 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe);
891 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe);
896 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe);
899 /* Timeouts do not return EWOULDBLOCK. */
900 if (error == EWOULDBLOCK)
909 sys_kevent(struct kevent_args *uap)
911 struct thread *td = curthread;
912 struct proc *p = td->td_proc;
913 struct timespec ts, *tsp;
915 struct file *fp = NULL;
916 struct kevent_copyin_args *kap, ka;
920 error = copyin(uap->timeout, &ts, sizeof(ts));
927 fp = holdfp(p->p_fd, uap->fd, -1);
930 if (fp->f_type != DTYPE_KQUEUE) {
935 kq = (struct kqueue *)fp->f_data;
941 error = kern_kevent(kq, uap->nevents, &uap->sysmsg_result, kap,
942 kevent_copyin, kevent_copyout, tsp);
950 kqueue_register(struct kqueue *kq, struct kevent *kev)
952 struct lwkt_token *tok;
953 struct filedesc *fdp = kq->kq_fdp;
954 struct filterops *fops;
955 struct file *fp = NULL;
956 struct knote *kn = NULL;
959 if (kev->filter < 0) {
960 if (kev->filter + EVFILT_SYSCOUNT < 0)
962 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */
966 * filter attach routine is responsible for insuring that
967 * the identifier can be attached to it.
972 tok = lwkt_token_pool_lookup(kq);
974 if (fops->f_flags & FILTEROP_ISFD) {
975 /* validate descriptor */
976 fp = holdfp(fdp, kev->ident, -1);
981 lwkt_getpooltoken(&fp->f_klist);
983 SLIST_FOREACH(kn, &fp->f_klist, kn_link) {
984 if (kn->kn_kq == kq &&
985 kn->kn_filter == kev->filter &&
986 kn->kn_id == kev->ident) {
987 if (knote_acquire(kn) == 0)
992 lwkt_relpooltoken(&fp->f_klist);
994 if (kq->kq_knhashmask) {
997 list = &kq->kq_knhash[
998 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
999 lwkt_getpooltoken(list);
1001 SLIST_FOREACH(kn, list, kn_link) {
1002 if (kn->kn_id == kev->ident &&
1003 kn->kn_filter == kev->filter) {
1004 if (knote_acquire(kn) == 0)
1009 lwkt_relpooltoken(list);
1014 * NOTE: At this point if kn is non-NULL we will have acquired
1015 * it and set KN_PROCESSING.
1017 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
1023 * kn now contains the matching knote, or NULL if no match
1025 if (kev->flags & EV_ADD) {
1033 * apply reference count to knote structure, and
1034 * do not release it at the end of this routine.
1038 kn->kn_sfflags = kev->fflags;
1039 kn->kn_sdata = kev->data;
1042 kn->kn_kevent = *kev;
1045 * KN_PROCESSING prevents the knote from getting
1046 * ripped out from under us while we are trying
1047 * to attach it, in case the attach blocks.
1049 kn->kn_status = KN_PROCESSING;
1051 if ((error = filter_attach(kn)) != 0) {
1052 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1058 * Interlock against close races which either tried
1059 * to remove our knote while we were blocked or missed
1060 * it entirely prior to our attachment. We do not
1061 * want to end up with a knote on a closed descriptor.
1063 if ((fops->f_flags & FILTEROP_ISFD) &&
1064 checkfdclosed(fdp, kev->ident, kn->kn_fp)) {
1065 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1069 * The user may change some filter values after the
1070 * initial EV_ADD, but doing so will not reset any
1071 * filter which have already been triggered.
1073 KKASSERT(kn->kn_status & KN_PROCESSING);
1074 if (fops == &user_filtops) {
1075 filt_usertouch(kn, kev, EVENT_REGISTER);
1077 kn->kn_sfflags = kev->fflags;
1078 kn->kn_sdata = kev->data;
1079 kn->kn_kevent.udata = kev->udata;
1084 * Execute the filter event to immediately activate the
1085 * knote if necessary. If reprocessing events are pending
1086 * due to blocking above we do not run the filter here
1087 * but instead let knote_release() do it. Otherwise we
1088 * might run the filter on a deleted event.
1090 if ((kn->kn_status & KN_REPROCESS) == 0) {
1091 if (filter_event(kn, 0))
1094 } else if (kev->flags & EV_DELETE) {
1096 * Delete the existing knote
1098 knote_detach_and_drop(kn);
1102 * Modify an existing event.
1104 * The user may change some filter values after the
1105 * initial EV_ADD, but doing so will not reset any
1106 * filter which have already been triggered.
1108 KKASSERT(kn->kn_status & KN_PROCESSING);
1109 if (fops == &user_filtops) {
1110 filt_usertouch(kn, kev, EVENT_REGISTER);
1112 kn->kn_sfflags = kev->fflags;
1113 kn->kn_sdata = kev->data;
1114 kn->kn_kevent.udata = kev->udata;
1118 * Execute the filter event to immediately activate the
1119 * knote if necessary. If reprocessing events are pending
1120 * due to blocking above we do not run the filter here
1121 * but instead let knote_release() do it. Otherwise we
1122 * might run the filter on a deleted event.
1124 if ((kn->kn_status & KN_REPROCESS) == 0) {
1125 if (filter_event(kn, 0))
1131 * Disablement does not deactivate a knote here.
1133 if ((kev->flags & EV_DISABLE) &&
1134 ((kn->kn_status & KN_DISABLED) == 0)) {
1135 kn->kn_status |= KN_DISABLED;
1139 * Re-enablement may have to immediately enqueue an active knote.
1141 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
1142 kn->kn_status &= ~KN_DISABLED;
1143 if ((kn->kn_status & KN_ACTIVE) &&
1144 ((kn->kn_status & KN_QUEUED) == 0)) {
1150 * Handle any required reprocessing
1153 /* kn may be invalid now */
1163 * Scan the kqueue, return the number of active events placed in kevp up
1166 * Continuous mode events may get recycled, do not continue scanning past
1167 * marker unless no events have been collected.
1170 kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count,
1171 struct knote *marker)
1173 struct knote *kn, local_marker;
1177 local_marker.kn_filter = EVFILT_MARKER;
1178 local_marker.kn_status = KN_PROCESSING;
1180 lwkt_getpooltoken(kq);
1185 TAILQ_INSERT_HEAD(&kq->kq_knpend, &local_marker, kn_tqe);
1187 kn = TAILQ_NEXT(&local_marker, kn_tqe);
1188 if (kn->kn_filter == EVFILT_MARKER) {
1189 /* Marker reached, we are done */
1193 /* Move local marker past some other threads marker */
1194 kn = TAILQ_NEXT(kn, kn_tqe);
1195 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe);
1196 TAILQ_INSERT_BEFORE(kn, &local_marker, kn_tqe);
1201 * We can't skip a knote undergoing processing, otherwise
1202 * we risk not returning it when the user process expects
1203 * it should be returned. Sleep and retry.
1205 if (knote_acquire(kn) == 0)
1209 * Remove the event for processing.
1211 * WARNING! We must leave KN_QUEUED set to prevent the
1212 * event from being KNOTE_ACTIVATE()d while
1213 * the queue state is in limbo, in case we
1216 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe);
1220 * We have to deal with an extremely important race against
1221 * file descriptor close()s here. The file descriptor can
1222 * disappear MPSAFE, and there is a small window of
1223 * opportunity between that and the call to knote_fdclose().
1225 * If we hit that window here while doselect or dopoll is
1226 * trying to delete a spurious event they will not be able
1227 * to match up the event against a knote and will go haywire.
1229 if ((kn->kn_fop->f_flags & FILTEROP_ISFD) &&
1230 checkfdclosed(kq->kq_fdp, kn->kn_kevent.ident, kn->kn_fp)) {
1231 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1234 if (kn->kn_status & KN_DISABLED) {
1236 * If disabled we ensure the event is not queued
1237 * but leave its active bit set. On re-enablement
1238 * the event may be immediately triggered.
1240 kn->kn_status &= ~KN_QUEUED;
1241 } else if ((kn->kn_flags & EV_ONESHOT) == 0 &&
1242 (kn->kn_status & KN_DELETING) == 0 &&
1243 filter_event(kn, 0) == 0) {
1245 * If not running in one-shot mode and the event
1246 * is no longer present we ensure it is removed
1247 * from the queue and ignore it.
1249 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
1254 if (kn->kn_fop == &user_filtops)
1255 filt_usertouch(kn, kevp, EVENT_PROCESS);
1257 *kevp = kn->kn_kevent;
1262 if (kn->kn_flags & EV_ONESHOT) {
1263 kn->kn_status &= ~KN_QUEUED;
1264 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1266 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
1267 if (kn->kn_flags & EV_CLEAR) {
1271 if (kn->kn_flags & EV_DISPATCH) {
1272 kn->kn_status |= KN_DISABLED;
1274 kn->kn_status &= ~(KN_QUEUED |
1277 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe);
1284 * Handle any post-processing states
1288 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe);
1290 lwkt_relpooltoken(kq);
1296 * This could be expanded to call kqueue_scan, if desired.
1301 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
1310 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
1319 kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
1320 struct ucred *cred, struct sysmsg *msg)
1322 struct lwkt_token *tok;
1326 kq = (struct kqueue *)fp->f_data;
1327 tok = lwkt_token_pool_lookup(kq);
1333 kq->kq_state |= KQ_ASYNC;
1335 kq->kq_state &= ~KQ_ASYNC;
1339 error = fsetown(*(int *)data, &kq->kq_sigio);
1353 kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred)
1355 struct kqueue *kq = (struct kqueue *)fp->f_data;
1357 bzero((void *)st, sizeof(*st));
1358 st->st_size = kq->kq_count;
1359 st->st_blksize = sizeof(struct kevent);
1360 st->st_mode = S_IFIFO;
1368 kqueue_close(struct file *fp)
1370 struct kqueue *kq = (struct kqueue *)fp->f_data;
1372 kqueue_terminate(kq);
1375 funsetown(&kq->kq_sigio);
1377 kfree(kq, M_KQUEUE);
1382 kqueue_wakeup(struct kqueue *kq)
1384 if (kq->kq_state & KQ_SLEEP) {
1385 kq->kq_state &= ~KQ_SLEEP;
1388 KNOTE(&kq->kq_kqinfo.ki_note, 0);
1392 * Calls filterops f_attach function, acquiring mplock if filter is not
1393 * marked as FILTEROP_MPSAFE.
1395 * Caller must be holding the related kq token
1398 filter_attach(struct knote *kn)
1402 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) {
1403 ret = kn->kn_fop->f_attach(kn);
1406 ret = kn->kn_fop->f_attach(kn);
1413 * Detach the knote and drop it, destroying the knote.
1415 * Calls filterops f_detach function, acquiring mplock if filter is not
1416 * marked as FILTEROP_MPSAFE.
1418 * Caller must be holding the related kq token
1421 knote_detach_and_drop(struct knote *kn)
1423 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1424 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) {
1425 kn->kn_fop->f_detach(kn);
1428 kn->kn_fop->f_detach(kn);
1435 * Calls filterops f_event function, acquiring mplock if filter is not
1436 * marked as FILTEROP_MPSAFE.
1438 * If the knote is in the middle of being created or deleted we cannot
1439 * safely call the filter op.
1441 * Caller must be holding the related kq token
1444 filter_event(struct knote *kn, long hint)
1448 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) {
1449 ret = kn->kn_fop->f_event(kn, hint);
1452 ret = kn->kn_fop->f_event(kn, hint);
1459 * Walk down a list of knotes, activating them if their event has triggered.
1461 * If we encounter any knotes which are undergoing processing we just mark
1462 * them for reprocessing and do not try to [re]activate the knote. However,
1463 * if a hint is being passed we have to wait and that makes things a bit
1467 knote(struct klist *list, long hint)
1471 struct knote *kntmp;
1473 lwkt_getpooltoken(list);
1475 SLIST_FOREACH(kn, list, kn_next) {
1477 lwkt_getpooltoken(kq);
1479 /* temporary verification hack */
1480 SLIST_FOREACH(kntmp, list, kn_next) {
1484 if (kn != kntmp || kn->kn_kq != kq) {
1485 lwkt_relpooltoken(kq);
1489 if (kn->kn_status & KN_PROCESSING) {
1491 * Someone else is processing the knote, ask the
1492 * other thread to reprocess it and don't mess
1493 * with it otherwise.
1496 kn->kn_status |= KN_REPROCESS;
1497 lwkt_relpooltoken(kq);
1502 * If the hint is non-zero we have to wait or risk
1503 * losing the state the caller is trying to update.
1505 * XXX This is a real problem, certain process
1506 * and signal filters will bump kn_data for
1507 * already-processed notes more than once if
1508 * we restart the list scan. FIXME.
1510 kn->kn_status |= KN_WAITING | KN_REPROCESS;
1511 tsleep(kn, 0, "knotec", hz);
1512 lwkt_relpooltoken(kq);
1517 * Become the reprocessing master ourselves.
1519 * If hint is non-zero running the event is mandatory
1520 * when not deleting so do it whether reprocessing is
1523 kn->kn_status |= KN_PROCESSING;
1524 if ((kn->kn_status & KN_DELETING) == 0) {
1525 if (filter_event(kn, hint))
1528 if (knote_release(kn)) {
1529 lwkt_relpooltoken(kq);
1532 lwkt_relpooltoken(kq);
1534 lwkt_relpooltoken(list);
1538 * Insert knote at head of klist.
1540 * This function may only be called via a filter function and thus
1541 * kq_token should already be held and marked for processing.
1544 knote_insert(struct klist *klist, struct knote *kn)
1546 lwkt_getpooltoken(klist);
1547 KKASSERT(kn->kn_status & KN_PROCESSING);
1548 SLIST_INSERT_HEAD(klist, kn, kn_next);
1549 lwkt_relpooltoken(klist);
1553 * Remove knote from a klist
1555 * This function may only be called via a filter function and thus
1556 * kq_token should already be held and marked for processing.
1559 knote_remove(struct klist *klist, struct knote *kn)
1561 lwkt_getpooltoken(klist);
1562 KKASSERT(kn->kn_status & KN_PROCESSING);
1563 SLIST_REMOVE(klist, kn, knote, kn_next);
1564 lwkt_relpooltoken(klist);
1569 * Remove all knotes from a specified klist
1571 * Only called from aio.
1574 knote_empty(struct klist *list)
1578 lwkt_gettoken(&kq_token);
1579 while ((kn = SLIST_FIRST(list)) != NULL) {
1580 if (knote_acquire(kn))
1581 knote_detach_and_drop(kn);
1583 lwkt_reltoken(&kq_token);
1588 knote_assume_knotes(struct kqinfo *src, struct kqinfo *dst,
1589 struct filterops *ops, void *hook)
1594 lwkt_getpooltoken(&src->ki_note);
1595 lwkt_getpooltoken(&dst->ki_note);
1596 while ((kn = SLIST_FIRST(&src->ki_note)) != NULL) {
1598 lwkt_getpooltoken(kq);
1599 if (SLIST_FIRST(&src->ki_note) != kn || kn->kn_kq != kq) {
1600 lwkt_relpooltoken(kq);
1603 if (knote_acquire(kn)) {
1604 knote_remove(&src->ki_note, kn);
1607 knote_insert(&dst->ki_note, kn);
1609 /* kn may be invalid now */
1611 lwkt_relpooltoken(kq);
1613 lwkt_relpooltoken(&dst->ki_note);
1614 lwkt_relpooltoken(&src->ki_note);
1618 * Remove all knotes referencing a specified fd
1621 knote_fdclose(struct file *fp, struct filedesc *fdp, int fd)
1625 struct knote *kntmp;
1627 lwkt_getpooltoken(&fp->f_klist);
1629 SLIST_FOREACH(kn, &fp->f_klist, kn_link) {
1630 if (kn->kn_kq->kq_fdp == fdp && kn->kn_id == fd) {
1632 lwkt_getpooltoken(kq);
1634 /* temporary verification hack */
1635 SLIST_FOREACH(kntmp, &fp->f_klist, kn_link) {
1639 if (kn != kntmp || kn->kn_kq->kq_fdp != fdp ||
1640 kn->kn_id != fd || kn->kn_kq != kq) {
1641 lwkt_relpooltoken(kq);
1644 if (knote_acquire(kn))
1645 knote_detach_and_drop(kn);
1646 lwkt_relpooltoken(kq);
1650 lwkt_relpooltoken(&fp->f_klist);
1654 * Low level attach function.
1656 * The knote should already be marked for processing.
1657 * Caller must hold the related kq token.
1660 knote_attach(struct knote *kn)
1663 struct kqueue *kq = kn->kn_kq;
1665 if (kn->kn_fop->f_flags & FILTEROP_ISFD) {
1666 KKASSERT(kn->kn_fp);
1667 list = &kn->kn_fp->f_klist;
1669 if (kq->kq_knhashmask == 0)
1670 kq->kq_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
1671 &kq->kq_knhashmask);
1672 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
1674 lwkt_getpooltoken(list);
1675 SLIST_INSERT_HEAD(list, kn, kn_link);
1676 TAILQ_INSERT_HEAD(&kq->kq_knlist, kn, kn_kqlink);
1677 lwkt_relpooltoken(list);
1681 * Low level drop function.
1683 * The knote should already be marked for processing.
1684 * Caller must hold the related kq token.
1687 knote_drop(struct knote *kn)
1694 if (kn->kn_fop->f_flags & FILTEROP_ISFD)
1695 list = &kn->kn_fp->f_klist;
1697 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
1699 lwkt_getpooltoken(list);
1700 SLIST_REMOVE(list, kn, knote, kn_link);
1701 TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink);
1702 if (kn->kn_status & KN_QUEUED)
1704 if (kn->kn_fop->f_flags & FILTEROP_ISFD) {
1709 lwkt_relpooltoken(list);
1713 * Low level enqueue function.
1715 * The knote should already be marked for processing.
1716 * Caller must be holding the kq token
1719 knote_enqueue(struct knote *kn)
1721 struct kqueue *kq = kn->kn_kq;
1723 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
1724 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe);
1725 kn->kn_status |= KN_QUEUED;
1729 * Send SIGIO on request (typically set up as a mailbox signal)
1731 if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1)
1732 pgsigio(kq->kq_sigio, SIGIO, 0);
1738 * Low level dequeue function.
1740 * The knote should already be marked for processing.
1741 * Caller must be holding the kq token
1744 knote_dequeue(struct knote *kn)
1746 struct kqueue *kq = kn->kn_kq;
1748 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
1749 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe);
1750 kn->kn_status &= ~KN_QUEUED;
1754 static struct knote *
1757 return kmalloc(sizeof(struct knote), M_KQUEUE, M_WAITOK);
1761 knote_free(struct knote *kn)
1763 kfree(kn, M_KQUEUE);