FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_event.c
1 /*-
2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
13 *
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
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: releng/5.0/sys/kern/kern_event.c 106171 2002-10-29 20:51:44Z rwatson $
27 */
28
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/kernel.h>
32 #include <sys/lock.h>
33 #include <sys/mutex.h>
34 #include <sys/proc.h>
35 #include <sys/malloc.h>
36 #include <sys/unistd.h>
37 #include <sys/file.h>
38 #include <sys/fcntl.h>
39 #include <sys/selinfo.h>
40 #include <sys/queue.h>
41 #include <sys/event.h>
42 #include <sys/eventvar.h>
43 #include <sys/poll.h>
44 #include <sys/protosw.h>
45 #include <sys/socket.h>
46 #include <sys/socketvar.h>
47 #include <sys/stat.h>
48 #include <sys/sysctl.h>
49 #include <sys/sysproto.h>
50 #include <sys/uio.h>
51
52 #include <vm/uma.h>
53
54 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
55
56 static int kqueue_scan(struct file *fp, int maxevents,
57 struct kevent *ulistp, const struct timespec *timeout,
58 struct thread *td);
59 static int kqueue_read(struct file *fp, struct uio *uio,
60 struct ucred *active_cred, int flags, struct thread *td);
61 static int kqueue_write(struct file *fp, struct uio *uio,
62 struct ucred *active_cred, int flags, struct thread *td);
63 static int kqueue_ioctl(struct file *fp, u_long com, void *data,
64 struct ucred *active_cred, struct thread *td);
65 static int kqueue_poll(struct file *fp, int events,
66 struct ucred *active_cred, struct thread *td);
67 static int kqueue_kqfilter(struct file *fp, struct knote *kn);
68 static int kqueue_stat(struct file *fp, struct stat *st,
69 struct ucred *active_cred, struct thread *td);
70 static int kqueue_close(struct file *fp, struct thread *td);
71 static void kqueue_wakeup(struct kqueue *kq);
72
73 static struct fileops kqueueops = {
74 kqueue_read,
75 kqueue_write,
76 kqueue_ioctl,
77 kqueue_poll,
78 kqueue_kqfilter,
79 kqueue_stat,
80 kqueue_close
81 };
82
83 static void knote_attach(struct knote *kn, struct filedesc *fdp);
84 static void knote_drop(struct knote *kn, struct thread *td);
85 static void knote_enqueue(struct knote *kn);
86 static void knote_dequeue(struct knote *kn);
87 static void knote_init(void);
88 static struct knote *knote_alloc(void);
89 static void knote_free(struct knote *kn);
90
91 static void filt_kqdetach(struct knote *kn);
92 static int filt_kqueue(struct knote *kn, long hint);
93 static int filt_procattach(struct knote *kn);
94 static void filt_procdetach(struct knote *kn);
95 static int filt_proc(struct knote *kn, long hint);
96 static int filt_fileattach(struct knote *kn);
97 static void filt_timerexpire(void *knx);
98 static int filt_timerattach(struct knote *kn);
99 static void filt_timerdetach(struct knote *kn);
100 static int filt_timer(struct knote *kn, long hint);
101
102 static struct filterops file_filtops =
103 { 1, filt_fileattach, NULL, NULL };
104 static struct filterops kqread_filtops =
105 { 1, NULL, filt_kqdetach, filt_kqueue };
106 static struct filterops proc_filtops =
107 { 0, filt_procattach, filt_procdetach, filt_proc };
108 static struct filterops timer_filtops =
109 { 0, filt_timerattach, filt_timerdetach, filt_timer };
110
111 static uma_zone_t knote_zone;
112 static int kq_ncallouts = 0;
113 static int kq_calloutmax = (4 * 1024);
114 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
115 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
116
117 #define KNOTE_ACTIVATE(kn) do { \
118 kn->kn_status |= KN_ACTIVE; \
119 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
120 knote_enqueue(kn); \
121 } while(0)
122
123 #define KN_HASHSIZE 64 /* XXX should be tunable */
124 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
125
126 static int
127 filt_nullattach(struct knote *kn)
128 {
129
130 return (ENXIO);
131 };
132
133 struct filterops null_filtops =
134 { 0, filt_nullattach, NULL, NULL };
135
136 extern struct filterops sig_filtops;
137
138 /*
139 * Table for for all system-defined filters.
140 */
141 static struct filterops *sysfilt_ops[] = {
142 &file_filtops, /* EVFILT_READ */
143 &file_filtops, /* EVFILT_WRITE */
144 &null_filtops, /* EVFILT_AIO */
145 &file_filtops, /* EVFILT_VNODE */
146 &proc_filtops, /* EVFILT_PROC */
147 &sig_filtops, /* EVFILT_SIGNAL */
148 &timer_filtops, /* EVFILT_TIMER */
149 &file_filtops, /* EVFILT_NETDEV */
150 };
151
152 static int
153 filt_fileattach(struct knote *kn)
154 {
155
156 return (fo_kqfilter(kn->kn_fp, kn));
157 }
158
159 /*ARGSUSED*/
160 static int
161 kqueue_kqfilter(struct file *fp, struct knote *kn)
162 {
163 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
164
165 if (kn->kn_filter != EVFILT_READ)
166 return (1);
167
168 kn->kn_fop = &kqread_filtops;
169 SLIST_INSERT_HEAD(&kq->kq_sel.si_note, kn, kn_selnext);
170 return (0);
171 }
172
173 static void
174 filt_kqdetach(struct knote *kn)
175 {
176 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
177
178 SLIST_REMOVE(&kq->kq_sel.si_note, kn, knote, kn_selnext);
179 }
180
181 /*ARGSUSED*/
182 static int
183 filt_kqueue(struct knote *kn, long hint)
184 {
185 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
186
187 kn->kn_data = kq->kq_count;
188 return (kn->kn_data > 0);
189 }
190
191 static int
192 filt_procattach(struct knote *kn)
193 {
194 struct proc *p;
195 int error;
196
197 p = pfind(kn->kn_id);
198 if (p == NULL)
199 return (ESRCH);
200 if ((error = p_cansee(curthread, p))) {
201 PROC_UNLOCK(p);
202 return (error);
203 }
204
205 kn->kn_ptr.p_proc = p;
206 kn->kn_flags |= EV_CLEAR; /* automatically set */
207
208 /*
209 * internal flag indicating registration done by kernel
210 */
211 if (kn->kn_flags & EV_FLAG1) {
212 kn->kn_data = kn->kn_sdata; /* ppid */
213 kn->kn_fflags = NOTE_CHILD;
214 kn->kn_flags &= ~EV_FLAG1;
215 }
216
217 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
218 PROC_UNLOCK(p);
219
220 return (0);
221 }
222
223 /*
224 * The knote may be attached to a different process, which may exit,
225 * leaving nothing for the knote to be attached to. So when the process
226 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
227 * it will be deleted when read out. However, as part of the knote deletion,
228 * this routine is called, so a check is needed to avoid actually performing
229 * a detach, because the original process does not exist any more.
230 */
231 static void
232 filt_procdetach(struct knote *kn)
233 {
234 struct proc *p = kn->kn_ptr.p_proc;
235
236 if (kn->kn_status & KN_DETACHED)
237 return;
238
239 PROC_LOCK(p);
240 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
241 PROC_UNLOCK(p);
242 }
243
244 static int
245 filt_proc(struct knote *kn, long hint)
246 {
247 u_int event;
248
249 /*
250 * mask off extra data
251 */
252 event = (u_int)hint & NOTE_PCTRLMASK;
253
254 /*
255 * if the user is interested in this event, record it.
256 */
257 if (kn->kn_sfflags & event)
258 kn->kn_fflags |= event;
259
260 /*
261 * process is gone, so flag the event as finished.
262 */
263 if (event == NOTE_EXIT) {
264 kn->kn_status |= KN_DETACHED;
265 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
266 return (1);
267 }
268
269 /*
270 * process forked, and user wants to track the new process,
271 * so attach a new knote to it, and immediately report an
272 * event with the parent's pid.
273 */
274 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
275 struct kevent kev;
276 int error;
277
278 /*
279 * register knote with new process.
280 */
281 kev.ident = hint & NOTE_PDATAMASK; /* pid */
282 kev.filter = kn->kn_filter;
283 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
284 kev.fflags = kn->kn_sfflags;
285 kev.data = kn->kn_id; /* parent */
286 kev.udata = kn->kn_kevent.udata; /* preserve udata */
287 error = kqueue_register(kn->kn_kq, &kev, NULL);
288 if (error)
289 kn->kn_fflags |= NOTE_TRACKERR;
290 }
291
292 return (kn->kn_fflags != 0);
293 }
294
295 static void
296 filt_timerexpire(void *knx)
297 {
298 struct knote *kn = knx;
299 struct callout *calloutp;
300 struct timeval tv;
301 int tticks;
302
303 kn->kn_data++;
304 KNOTE_ACTIVATE(kn);
305
306 if ((kn->kn_flags & EV_ONESHOT) == 0) {
307 tv.tv_sec = kn->kn_sdata / 1000;
308 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
309 tticks = tvtohz(&tv);
310 calloutp = (struct callout *)kn->kn_hook;
311 callout_reset(calloutp, tticks, filt_timerexpire, kn);
312 }
313 }
314
315 /*
316 * data contains amount of time to sleep, in milliseconds
317 */
318 static int
319 filt_timerattach(struct knote *kn)
320 {
321 struct callout *calloutp;
322 struct timeval tv;
323 int tticks;
324
325 if (kq_ncallouts >= kq_calloutmax)
326 return (ENOMEM);
327 kq_ncallouts++;
328
329 tv.tv_sec = kn->kn_sdata / 1000;
330 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
331 tticks = tvtohz(&tv);
332
333 kn->kn_flags |= EV_CLEAR; /* automatically set */
334 MALLOC(calloutp, struct callout *, sizeof(*calloutp),
335 M_KQUEUE, M_WAITOK);
336 callout_init(calloutp, 0);
337 callout_reset(calloutp, tticks, filt_timerexpire, kn);
338 kn->kn_hook = calloutp;
339
340 return (0);
341 }
342
343 static void
344 filt_timerdetach(struct knote *kn)
345 {
346 struct callout *calloutp;
347
348 calloutp = (struct callout *)kn->kn_hook;
349 callout_stop(calloutp);
350 FREE(calloutp, M_KQUEUE);
351 kq_ncallouts--;
352 }
353
354 static int
355 filt_timer(struct knote *kn, long hint)
356 {
357
358 return (kn->kn_data != 0);
359 }
360
361 /*
362 * MPSAFE
363 */
364 int
365 kqueue(struct thread *td, struct kqueue_args *uap)
366 {
367 struct filedesc *fdp;
368 struct kqueue *kq;
369 struct file *fp;
370 int fd, error;
371
372 mtx_lock(&Giant);
373 fdp = td->td_proc->p_fd;
374 error = falloc(td, &fp, &fd);
375 if (error)
376 goto done2;
377 kq = malloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO);
378 TAILQ_INIT(&kq->kq_head);
379 FILE_LOCK(fp);
380 fp->f_flag = FREAD | FWRITE;
381 fp->f_type = DTYPE_KQUEUE;
382 fp->f_ops = &kqueueops;
383 TAILQ_INIT(&kq->kq_head);
384 fp->f_data = kq;
385 FILE_UNLOCK(fp);
386 FILEDESC_LOCK(fdp);
387 td->td_retval[0] = fd;
388 if (fdp->fd_knlistsize < 0)
389 fdp->fd_knlistsize = 0; /* this process has a kq */
390 FILEDESC_UNLOCK(fdp);
391 kq->kq_fdp = fdp;
392 done2:
393 mtx_unlock(&Giant);
394 return (error);
395 }
396
397 #ifndef _SYS_SYSPROTO_H_
398 struct kevent_args {
399 int fd;
400 const struct kevent *changelist;
401 int nchanges;
402 struct kevent *eventlist;
403 int nevents;
404 const struct timespec *timeout;
405 };
406 #endif
407 /*
408 * MPSAFE
409 */
410 int
411 kevent(struct thread *td, struct kevent_args *uap)
412 {
413 struct kevent *kevp;
414 struct kqueue *kq;
415 struct file *fp;
416 struct timespec ts;
417 int i, n, nerrors, error;
418
419 if ((error = fget(td, uap->fd, &fp)) != 0)
420 return (error);
421 if (fp->f_type != DTYPE_KQUEUE) {
422 fdrop(fp, td);
423 return (EBADF);
424 }
425 if (uap->timeout != NULL) {
426 error = copyin(uap->timeout, &ts, sizeof(ts));
427 if (error)
428 goto done_nogiant;
429 uap->timeout = &ts;
430 }
431 mtx_lock(&Giant);
432
433 kq = (struct kqueue *)fp->f_data;
434 nerrors = 0;
435
436 while (uap->nchanges > 0) {
437 n = uap->nchanges > KQ_NEVENTS ? KQ_NEVENTS : uap->nchanges;
438 error = copyin(uap->changelist, kq->kq_kev,
439 n * sizeof(struct kevent));
440 if (error)
441 goto done;
442 for (i = 0; i < n; i++) {
443 kevp = &kq->kq_kev[i];
444 kevp->flags &= ~EV_SYSFLAGS;
445 error = kqueue_register(kq, kevp, td);
446 if (error) {
447 if (uap->nevents != 0) {
448 kevp->flags = EV_ERROR;
449 kevp->data = error;
450 (void) copyout(kevp,
451 uap->eventlist,
452 sizeof(*kevp));
453 uap->eventlist++;
454 uap->nevents--;
455 nerrors++;
456 } else {
457 goto done;
458 }
459 }
460 }
461 uap->nchanges -= n;
462 uap->changelist += n;
463 }
464 if (nerrors) {
465 td->td_retval[0] = nerrors;
466 error = 0;
467 goto done;
468 }
469
470 error = kqueue_scan(fp, uap->nevents, uap->eventlist, uap->timeout, td);
471 done:
472 mtx_unlock(&Giant);
473 done_nogiant:
474 if (fp != NULL)
475 fdrop(fp, td);
476 return (error);
477 }
478
479 int
480 kqueue_add_filteropts(int filt, struct filterops *filtops)
481 {
482
483 if (filt > 0)
484 panic("filt(%d) > 0", filt);
485 if (filt + EVFILT_SYSCOUNT < 0)
486 panic("filt(%d) + EVFILT_SYSCOUNT(%d) == %d < 0",
487 filt, EVFILT_SYSCOUNT, filt + EVFILT_SYSCOUNT);
488 if (sysfilt_ops[~filt] != &null_filtops)
489 panic("sysfilt_ops[~filt(%d)] != &null_filtops", filt);
490 sysfilt_ops[~filt] = filtops;
491 return (0);
492 }
493
494 int
495 kqueue_del_filteropts(int filt)
496 {
497
498 if (filt > 0)
499 panic("filt(%d) > 0", filt);
500 if (filt + EVFILT_SYSCOUNT < 0)
501 panic("filt(%d) + EVFILT_SYSCOUNT(%d) == %d < 0",
502 filt, EVFILT_SYSCOUNT, filt + EVFILT_SYSCOUNT);
503 if (sysfilt_ops[~filt] == &null_filtops)
504 panic("sysfilt_ops[~filt(%d)] != &null_filtops", filt);
505 sysfilt_ops[~filt] = &null_filtops;
506 return (0);
507 }
508
509 int
510 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td)
511 {
512 struct filedesc *fdp = kq->kq_fdp;
513 struct filterops *fops;
514 struct file *fp = NULL;
515 struct knote *kn = NULL;
516 int s, error = 0;
517
518 if (kev->filter < 0) {
519 if (kev->filter + EVFILT_SYSCOUNT < 0)
520 return (EINVAL);
521 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */
522 } else {
523 /*
524 * XXX
525 * filter attach routine is responsible for insuring that
526 * the identifier can be attached to it.
527 */
528 printf("unknown filter: %d\n", kev->filter);
529 return (EINVAL);
530 }
531
532 FILEDESC_LOCK(fdp);
533 if (fops->f_isfd) {
534 /* validate descriptor */
535 if ((u_int)kev->ident >= fdp->fd_nfiles ||
536 (fp = fdp->fd_ofiles[kev->ident]) == NULL) {
537 FILEDESC_UNLOCK(fdp);
538 return (EBADF);
539 }
540 fhold(fp);
541
542 if (kev->ident < fdp->fd_knlistsize) {
543 SLIST_FOREACH(kn, &fdp->fd_knlist[kev->ident], kn_link)
544 if (kq == kn->kn_kq &&
545 kev->filter == kn->kn_filter)
546 break;
547 }
548 } else {
549 if (fdp->fd_knhashmask != 0) {
550 struct klist *list;
551
552 list = &fdp->fd_knhash[
553 KN_HASH((u_long)kev->ident, fdp->fd_knhashmask)];
554 SLIST_FOREACH(kn, list, kn_link)
555 if (kev->ident == kn->kn_id &&
556 kq == kn->kn_kq &&
557 kev->filter == kn->kn_filter)
558 break;
559 }
560 }
561 FILEDESC_UNLOCK(fdp);
562
563 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
564 error = ENOENT;
565 goto done;
566 }
567
568 /*
569 * kn now contains the matching knote, or NULL if no match
570 */
571 if (kev->flags & EV_ADD) {
572
573 if (kn == NULL) {
574 kn = knote_alloc();
575 if (kn == NULL) {
576 error = ENOMEM;
577 goto done;
578 }
579 kn->kn_fp = fp;
580 kn->kn_kq = kq;
581 kn->kn_fop = fops;
582
583 /*
584 * apply reference count to knote structure, and
585 * do not release it at the end of this routine.
586 */
587 fp = NULL;
588
589 kn->kn_sfflags = kev->fflags;
590 kn->kn_sdata = kev->data;
591 kev->fflags = 0;
592 kev->data = 0;
593 kn->kn_kevent = *kev;
594
595 knote_attach(kn, fdp);
596 if ((error = fops->f_attach(kn)) != 0) {
597 knote_drop(kn, td);
598 goto done;
599 }
600 } else {
601 /*
602 * The user may change some filter values after the
603 * initial EV_ADD, but doing so will not reset any
604 * filter which has already been triggered.
605 */
606 kn->kn_sfflags = kev->fflags;
607 kn->kn_sdata = kev->data;
608 kn->kn_kevent.udata = kev->udata;
609 }
610
611 s = splhigh();
612 if (kn->kn_fop->f_event(kn, 0))
613 KNOTE_ACTIVATE(kn);
614 splx(s);
615
616 } else if (kev->flags & EV_DELETE) {
617 kn->kn_fop->f_detach(kn);
618 knote_drop(kn, td);
619 goto done;
620 }
621
622 if ((kev->flags & EV_DISABLE) &&
623 ((kn->kn_status & KN_DISABLED) == 0)) {
624 s = splhigh();
625 kn->kn_status |= KN_DISABLED;
626 splx(s);
627 }
628
629 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
630 s = splhigh();
631 kn->kn_status &= ~KN_DISABLED;
632 if ((kn->kn_status & KN_ACTIVE) &&
633 ((kn->kn_status & KN_QUEUED) == 0))
634 knote_enqueue(kn);
635 splx(s);
636 }
637
638 done:
639 if (fp != NULL)
640 fdrop(fp, td);
641 return (error);
642 }
643
644 static int
645 kqueue_scan(struct file *fp, int maxevents, struct kevent *ulistp,
646 const struct timespec *tsp, struct thread *td)
647 {
648 struct kqueue *kq;
649 struct kevent *kevp;
650 struct timeval atv, rtv, ttv;
651 struct knote *kn, marker;
652 int s, count, timeout, nkev = 0, error = 0;
653
654 FILE_LOCK_ASSERT(fp, MA_NOTOWNED);
655
656 kq = (struct kqueue *)fp->f_data;
657 count = maxevents;
658 if (count == 0)
659 goto done;
660
661 if (tsp != NULL) {
662 TIMESPEC_TO_TIMEVAL(&atv, tsp);
663 if (itimerfix(&atv)) {
664 error = EINVAL;
665 goto done;
666 }
667 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
668 timeout = -1;
669 else
670 timeout = atv.tv_sec > 24 * 60 * 60 ?
671 24 * 60 * 60 * hz : tvtohz(&atv);
672 getmicrouptime(&rtv);
673 timevaladd(&atv, &rtv);
674 } else {
675 atv.tv_sec = 0;
676 atv.tv_usec = 0;
677 timeout = 0;
678 }
679 goto start;
680
681 retry:
682 if (atv.tv_sec || atv.tv_usec) {
683 getmicrouptime(&rtv);
684 if (timevalcmp(&rtv, &atv, >=))
685 goto done;
686 ttv = atv;
687 timevalsub(&ttv, &rtv);
688 timeout = ttv.tv_sec > 24 * 60 * 60 ?
689 24 * 60 * 60 * hz : tvtohz(&ttv);
690 }
691
692 start:
693 kevp = kq->kq_kev;
694 s = splhigh();
695 if (kq->kq_count == 0) {
696 if (timeout < 0) {
697 error = EWOULDBLOCK;
698 } else {
699 kq->kq_state |= KQ_SLEEP;
700 error = tsleep(kq, PSOCK | PCATCH, "kqread", timeout);
701 }
702 splx(s);
703 if (error == 0)
704 goto retry;
705 /* don't restart after signals... */
706 if (error == ERESTART)
707 error = EINTR;
708 else if (error == EWOULDBLOCK)
709 error = 0;
710 goto done;
711 }
712
713 TAILQ_INSERT_TAIL(&kq->kq_head, &marker, kn_tqe);
714 while (count) {
715 kn = TAILQ_FIRST(&kq->kq_head);
716 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
717 if (kn == &marker) {
718 splx(s);
719 if (count == maxevents)
720 goto retry;
721 goto done;
722 }
723 if (kn->kn_status & KN_DISABLED) {
724 kn->kn_status &= ~KN_QUEUED;
725 kq->kq_count--;
726 continue;
727 }
728 if ((kn->kn_flags & EV_ONESHOT) == 0 &&
729 kn->kn_fop->f_event(kn, 0) == 0) {
730 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
731 kq->kq_count--;
732 continue;
733 }
734 *kevp = kn->kn_kevent;
735 kevp++;
736 nkev++;
737 if (kn->kn_flags & EV_ONESHOT) {
738 kn->kn_status &= ~KN_QUEUED;
739 kq->kq_count--;
740 splx(s);
741 kn->kn_fop->f_detach(kn);
742 knote_drop(kn, td);
743 s = splhigh();
744 } else if (kn->kn_flags & EV_CLEAR) {
745 kn->kn_data = 0;
746 kn->kn_fflags = 0;
747 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
748 kq->kq_count--;
749 } else {
750 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
751 }
752 count--;
753 if (nkev == KQ_NEVENTS) {
754 splx(s);
755 error = copyout(&kq->kq_kev, ulistp,
756 sizeof(struct kevent) * nkev);
757 ulistp += nkev;
758 nkev = 0;
759 kevp = kq->kq_kev;
760 s = splhigh();
761 if (error)
762 break;
763 }
764 }
765 TAILQ_REMOVE(&kq->kq_head, &marker, kn_tqe);
766 splx(s);
767 done:
768 if (nkev != 0)
769 error = copyout(&kq->kq_kev, ulistp,
770 sizeof(struct kevent) * nkev);
771 td->td_retval[0] = maxevents - count;
772 return (error);
773 }
774
775 /*
776 * XXX
777 * This could be expanded to call kqueue_scan, if desired.
778 */
779 /*ARGSUSED*/
780 static int
781 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
782 int flags, struct thread *td)
783 {
784 return (ENXIO);
785 }
786
787 /*ARGSUSED*/
788 static int
789 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
790 int flags, struct thread *td)
791 {
792 return (ENXIO);
793 }
794
795 /*ARGSUSED*/
796 static int
797 kqueue_ioctl(struct file *fp, u_long com, void *data,
798 struct ucred *active_cred, struct thread *td)
799 {
800 return (ENOTTY);
801 }
802
803 /*ARGSUSED*/
804 static int
805 kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
806 struct thread *td)
807 {
808 struct kqueue *kq;
809 int revents = 0;
810 int s = splnet();
811
812 kq = (struct kqueue *)fp->f_data;
813 if (events & (POLLIN | POLLRDNORM)) {
814 if (kq->kq_count) {
815 revents |= events & (POLLIN | POLLRDNORM);
816 } else {
817 selrecord(td, &kq->kq_sel);
818 kq->kq_state |= KQ_SEL;
819 }
820 }
821 splx(s);
822 return (revents);
823 }
824
825 /*ARGSUSED*/
826 static int
827 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
828 struct thread *td)
829 {
830 struct kqueue *kq;
831
832 kq = (struct kqueue *)fp->f_data;
833 bzero((void *)st, sizeof(*st));
834 st->st_size = kq->kq_count;
835 st->st_blksize = sizeof(struct kevent);
836 st->st_mode = S_IFIFO;
837 return (0);
838 }
839
840 /*ARGSUSED*/
841 static int
842 kqueue_close(struct file *fp, struct thread *td)
843 {
844 struct kqueue *kq = (struct kqueue *)fp->f_data;
845 struct filedesc *fdp = td->td_proc->p_fd;
846 struct knote **knp, *kn, *kn0;
847 int i;
848
849 FILEDESC_LOCK(fdp);
850 for (i = 0; i < fdp->fd_knlistsize; i++) {
851 knp = &SLIST_FIRST(&fdp->fd_knlist[i]);
852 kn = *knp;
853 while (kn != NULL) {
854 kn0 = SLIST_NEXT(kn, kn_link);
855 if (kq == kn->kn_kq) {
856 kn->kn_fop->f_detach(kn);
857 *knp = kn0;
858 FILE_LOCK(kn->kn_fp);
859 FILEDESC_UNLOCK(fdp);
860 fdrop_locked(kn->kn_fp, td);
861 knote_free(kn);
862 FILEDESC_LOCK(fdp);
863 } else {
864 knp = &SLIST_NEXT(kn, kn_link);
865 }
866 kn = kn0;
867 }
868 }
869 if (fdp->fd_knhashmask != 0) {
870 for (i = 0; i < fdp->fd_knhashmask + 1; i++) {
871 knp = &SLIST_FIRST(&fdp->fd_knhash[i]);
872 kn = *knp;
873 while (kn != NULL) {
874 kn0 = SLIST_NEXT(kn, kn_link);
875 if (kq == kn->kn_kq) {
876 kn->kn_fop->f_detach(kn);
877 *knp = kn0;
878 /* XXX non-fd release of kn->kn_ptr */
879 FILEDESC_UNLOCK(fdp);
880 knote_free(kn);
881 FILEDESC_LOCK(fdp);
882 } else {
883 knp = &SLIST_NEXT(kn, kn_link);
884 }
885 kn = kn0;
886 }
887 }
888 }
889 FILEDESC_UNLOCK(fdp);
890 free(kq, M_KQUEUE);
891 fp->f_data = NULL;
892
893 return (0);
894 }
895
896 static void
897 kqueue_wakeup(struct kqueue *kq)
898 {
899
900 if (kq->kq_state & KQ_SLEEP) {
901 kq->kq_state &= ~KQ_SLEEP;
902 wakeup(kq);
903 }
904 if (kq->kq_state & KQ_SEL) {
905 kq->kq_state &= ~KQ_SEL;
906 selwakeup(&kq->kq_sel);
907 }
908 KNOTE(&kq->kq_sel.si_note, 0);
909 }
910
911 /*
912 * walk down a list of knotes, activating them if their event has triggered.
913 */
914 void
915 knote(struct klist *list, long hint)
916 {
917 struct knote *kn;
918
919 SLIST_FOREACH(kn, list, kn_selnext)
920 if (kn->kn_fop->f_event(kn, hint))
921 KNOTE_ACTIVATE(kn);
922 }
923
924 /*
925 * remove all knotes from a specified klist
926 */
927 void
928 knote_remove(struct thread *td, struct klist *list)
929 {
930 struct knote *kn;
931
932 while ((kn = SLIST_FIRST(list)) != NULL) {
933 kn->kn_fop->f_detach(kn);
934 knote_drop(kn, td);
935 }
936 }
937
938 /*
939 * remove all knotes referencing a specified fd
940 */
941 void
942 knote_fdclose(struct thread *td, int fd)
943 {
944 struct filedesc *fdp = td->td_proc->p_fd;
945 struct klist *list;
946
947 FILEDESC_LOCK(fdp);
948 list = &fdp->fd_knlist[fd];
949 FILEDESC_UNLOCK(fdp);
950 knote_remove(td, list);
951 }
952
953 static void
954 knote_attach(struct knote *kn, struct filedesc *fdp)
955 {
956 struct klist *list, *oldlist, *tmp_knhash;
957 u_long tmp_knhashmask;
958 int size, newsize;
959
960 FILEDESC_LOCK(fdp);
961
962 if (! kn->kn_fop->f_isfd) {
963 if (fdp->fd_knhashmask == 0) {
964 FILEDESC_UNLOCK(fdp);
965 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
966 &tmp_knhashmask);
967 FILEDESC_LOCK(fdp);
968 if (fdp->fd_knhashmask == 0) {
969 fdp->fd_knhash = tmp_knhash;
970 fdp->fd_knhashmask = tmp_knhashmask;
971 } else {
972 FILEDESC_UNLOCK(fdp);
973 free(tmp_knhash, M_KQUEUE);
974 FILEDESC_LOCK(fdp);
975 }
976 }
977 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
978 goto done;
979 }
980
981 if (fdp->fd_knlistsize <= kn->kn_id) {
982 retry:
983 size = fdp->fd_knlistsize;
984 while (size <= kn->kn_id)
985 size += KQEXTENT;
986 FILEDESC_UNLOCK(fdp);
987 MALLOC(list, struct klist *,
988 size * sizeof(struct klist *), M_KQUEUE, M_WAITOK);
989 FILEDESC_LOCK(fdp);
990 newsize = fdp->fd_knlistsize;
991 while (newsize <= kn->kn_id)
992 newsize += KQEXTENT;
993 if (newsize != size) {
994 FILEDESC_UNLOCK(fdp);
995 free(list, M_TEMP);
996 FILEDESC_LOCK(fdp);
997 goto retry;
998 }
999 bcopy(fdp->fd_knlist, list,
1000 fdp->fd_knlistsize * sizeof(struct klist *));
1001 bzero((caddr_t)list +
1002 fdp->fd_knlistsize * sizeof(struct klist *),
1003 (size - fdp->fd_knlistsize) * sizeof(struct klist *));
1004 if (fdp->fd_knlist != NULL)
1005 oldlist = fdp->fd_knlist;
1006 else
1007 oldlist = NULL;
1008 fdp->fd_knlistsize = size;
1009 fdp->fd_knlist = list;
1010 FILEDESC_UNLOCK(fdp);
1011 if (oldlist != NULL)
1012 FREE(oldlist, M_KQUEUE);
1013 FILEDESC_LOCK(fdp);
1014 }
1015 list = &fdp->fd_knlist[kn->kn_id];
1016 done:
1017 FILEDESC_UNLOCK(fdp);
1018 SLIST_INSERT_HEAD(list, kn, kn_link);
1019 kn->kn_status = 0;
1020 }
1021
1022 /*
1023 * should be called at spl == 0, since we don't want to hold spl
1024 * while calling fdrop and free.
1025 */
1026 static void
1027 knote_drop(struct knote *kn, struct thread *td)
1028 {
1029 struct filedesc *fdp = td->td_proc->p_fd;
1030 struct klist *list;
1031
1032 FILEDESC_LOCK(fdp);
1033 if (kn->kn_fop->f_isfd)
1034 list = &fdp->fd_knlist[kn->kn_id];
1035 else
1036 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
1037 if (kn->kn_fop->f_isfd)
1038 FILE_LOCK(kn->kn_fp);
1039 FILEDESC_UNLOCK(fdp);
1040
1041 SLIST_REMOVE(list, kn, knote, kn_link);
1042 if (kn->kn_status & KN_QUEUED)
1043 knote_dequeue(kn);
1044 if (kn->kn_fop->f_isfd)
1045 fdrop_locked(kn->kn_fp, td);
1046 knote_free(kn);
1047 }
1048
1049
1050 static void
1051 knote_enqueue(struct knote *kn)
1052 {
1053 struct kqueue *kq = kn->kn_kq;
1054 int s = splhigh();
1055
1056 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
1057
1058 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
1059 kn->kn_status |= KN_QUEUED;
1060 kq->kq_count++;
1061 splx(s);
1062 kqueue_wakeup(kq);
1063 }
1064
1065 static void
1066 knote_dequeue(struct knote *kn)
1067 {
1068 struct kqueue *kq = kn->kn_kq;
1069 int s = splhigh();
1070
1071 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
1072
1073 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
1074 kn->kn_status &= ~KN_QUEUED;
1075 kq->kq_count--;
1076 splx(s);
1077 }
1078
1079 static void
1080 knote_init(void)
1081 {
1082 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
1083 NULL, NULL, UMA_ALIGN_PTR, 0);
1084
1085 }
1086 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL)
1087
1088 static struct knote *
1089 knote_alloc(void)
1090 {
1091 return ((struct knote *)uma_zalloc(knote_zone, M_WAITOK));
1092 }
1093
1094 static void
1095 knote_free(struct knote *kn)
1096 {
1097 uma_zfree(knote_zone, kn);
1098 }
Cache object: 8a5053ec5bfef59ece848c1cd8bddba5
|