FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_event.c
1 /*-
2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
3 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30
31 #include "opt_ktrace.h"
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/kernel.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/proc.h>
39 #include <sys/malloc.h>
40 #include <sys/unistd.h>
41 #include <sys/file.h>
42 #include <sys/filedesc.h>
43 #include <sys/filio.h>
44 #include <sys/fcntl.h>
45 #include <sys/kthread.h>
46 #include <sys/selinfo.h>
47 #include <sys/queue.h>
48 #include <sys/event.h>
49 #include <sys/eventvar.h>
50 #include <sys/poll.h>
51 #include <sys/protosw.h>
52 #include <sys/sigio.h>
53 #include <sys/signalvar.h>
54 #include <sys/socket.h>
55 #include <sys/socketvar.h>
56 #include <sys/stat.h>
57 #include <sys/sysctl.h>
58 #include <sys/sysproto.h>
59 #include <sys/syscallsubr.h>
60 #include <sys/taskqueue.h>
61 #include <sys/uio.h>
62 #ifdef KTRACE
63 #include <sys/ktrace.h>
64 #endif
65
66 #include <vm/uma.h>
67
68 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
69
70 /*
71 * This lock is used if multiple kq locks are required. This possibly
72 * should be made into a per proc lock.
73 */
74 static struct mtx kq_global;
75 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF);
76 #define KQ_GLOBAL_LOCK(lck, haslck) do { \
77 if (!haslck) \
78 mtx_lock(lck); \
79 haslck = 1; \
80 } while (0)
81 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \
82 if (haslck) \
83 mtx_unlock(lck); \
84 haslck = 0; \
85 } while (0)
86
87 TASKQUEUE_DEFINE_THREAD(kqueue);
88
89 static int kevent_copyout(void *arg, struct kevent *kevp, int count);
90 static int kevent_copyin(void *arg, struct kevent *kevp, int count);
91 static int kqueue_register(struct kqueue *kq, struct kevent *kev,
92 struct thread *td, int waitok);
93 static int kqueue_acquire(struct file *fp, struct kqueue **kqp);
94 static void kqueue_release(struct kqueue *kq, int locked);
95 static int kqueue_expand(struct kqueue *kq, struct filterops *fops,
96 uintptr_t ident, int waitok);
97 static void kqueue_task(void *arg, int pending);
98 static int kqueue_scan(struct kqueue *kq, int maxevents,
99 struct kevent_copyops *k_ops,
100 const struct timespec *timeout,
101 struct kevent *keva, struct thread *td);
102 static void kqueue_wakeup(struct kqueue *kq);
103 static struct filterops *kqueue_fo_find(int filt);
104 static void kqueue_fo_release(int filt);
105
106 static fo_rdwr_t kqueue_read;
107 static fo_rdwr_t kqueue_write;
108 static fo_ioctl_t kqueue_ioctl;
109 static fo_poll_t kqueue_poll;
110 static fo_kqfilter_t kqueue_kqfilter;
111 static fo_stat_t kqueue_stat;
112 static fo_close_t kqueue_close;
113
114 static struct fileops kqueueops = {
115 .fo_read = kqueue_read,
116 .fo_write = kqueue_write,
117 .fo_ioctl = kqueue_ioctl,
118 .fo_poll = kqueue_poll,
119 .fo_kqfilter = kqueue_kqfilter,
120 .fo_stat = kqueue_stat,
121 .fo_close = kqueue_close,
122 };
123
124 static int knote_attach(struct knote *kn, struct kqueue *kq);
125 static void knote_drop(struct knote *kn, struct thread *td);
126 static void knote_enqueue(struct knote *kn);
127 static void knote_dequeue(struct knote *kn);
128 static void knote_init(void);
129 static struct knote *knote_alloc(int waitok);
130 static void knote_free(struct knote *kn);
131
132 static void filt_kqdetach(struct knote *kn);
133 static int filt_kqueue(struct knote *kn, long hint);
134 static int filt_procattach(struct knote *kn);
135 static void filt_procdetach(struct knote *kn);
136 static int filt_proc(struct knote *kn, long hint);
137 static int filt_fileattach(struct knote *kn);
138 static void filt_timerexpire(void *knx);
139 static int filt_timerattach(struct knote *kn);
140 static void filt_timerdetach(struct knote *kn);
141 static int filt_timer(struct knote *kn, long hint);
142
143 static struct filterops file_filtops =
144 { 1, filt_fileattach, NULL, NULL };
145 static struct filterops kqread_filtops =
146 { 1, NULL, filt_kqdetach, filt_kqueue };
147 /* XXX - move to kern_proc.c? */
148 static struct filterops proc_filtops =
149 { 0, filt_procattach, filt_procdetach, filt_proc };
150 static struct filterops timer_filtops =
151 { 0, filt_timerattach, filt_timerdetach, filt_timer };
152
153 static uma_zone_t knote_zone;
154 static int kq_ncallouts = 0;
155 static int kq_calloutmax = (4 * 1024);
156 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
157 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
158
159 /* XXX - ensure not KN_INFLUX?? */
160 #define KNOTE_ACTIVATE(kn, islock) do { \
161 if ((islock)) \
162 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \
163 else \
164 KQ_LOCK((kn)->kn_kq); \
165 (kn)->kn_status |= KN_ACTIVE; \
166 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
167 knote_enqueue((kn)); \
168 if (!(islock)) \
169 KQ_UNLOCK((kn)->kn_kq); \
170 } while(0)
171 #define KQ_LOCK(kq) do { \
172 mtx_lock(&(kq)->kq_lock); \
173 } while (0)
174 #define KQ_FLUX_WAKEUP(kq) do { \
175 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \
176 (kq)->kq_state &= ~KQ_FLUXWAIT; \
177 wakeup((kq)); \
178 } \
179 } while (0)
180 #define KQ_UNLOCK_FLUX(kq) do { \
181 KQ_FLUX_WAKEUP(kq); \
182 mtx_unlock(&(kq)->kq_lock); \
183 } while (0)
184 #define KQ_UNLOCK(kq) do { \
185 mtx_unlock(&(kq)->kq_lock); \
186 } while (0)
187 #define KQ_OWNED(kq) do { \
188 mtx_assert(&(kq)->kq_lock, MA_OWNED); \
189 } while (0)
190 #define KQ_NOTOWNED(kq) do { \
191 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \
192 } while (0)
193 #define KN_LIST_LOCK(kn) do { \
194 if (kn->kn_knlist != NULL) \
195 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \
196 } while (0)
197 #define KN_LIST_UNLOCK(kn) do { \
198 if (kn->kn_knlist != NULL) \
199 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \
200 } while (0)
201 #define KNL_ASSERT_LOCK(knl, islocked) do { \
202 if (islocked) \
203 KNL_ASSERT_LOCKED(knl); \
204 else \
205 KNL_ASSERT_UNLOCKED(knl); \
206 } while (0)
207 #ifdef INVARIANTS
208 #define KNL_ASSERT_LOCKED(knl) do { \
209 if (knl->kl_locked != NULL && \
210 !knl->kl_locked((knl)->kl_lockarg)) \
211 panic("knlist not locked, but should be"); \
212 } while (0)
213 #define KNL_ASSERT_UNLOCKED(knl) do { \
214 if (knl->kl_locked != NULL && \
215 knl->kl_locked((knl)->kl_lockarg)) \
216 panic("knlist locked, but should not be"); \
217 } while (0)
218 #else /* !INVARIANTS */
219 #define KNL_ASSERT_LOCKED(knl) do {} while(0)
220 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
221 #endif /* INVARIANTS */
222
223 #define KN_HASHSIZE 64 /* XXX should be tunable */
224 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
225
226 static int
227 filt_nullattach(struct knote *kn)
228 {
229
230 return (ENXIO);
231 };
232
233 struct filterops null_filtops =
234 { 0, filt_nullattach, NULL, NULL };
235
236 /* XXX - make SYSINIT to add these, and move into respective modules. */
237 extern struct filterops sig_filtops;
238 extern struct filterops fs_filtops;
239
240 /*
241 * Table for for all system-defined filters.
242 */
243 static struct mtx filterops_lock;
244 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops",
245 MTX_DEF);
246 static struct {
247 struct filterops *for_fop;
248 int for_refcnt;
249 } sysfilt_ops[EVFILT_SYSCOUNT] = {
250 { &file_filtops }, /* EVFILT_READ */
251 { &file_filtops }, /* EVFILT_WRITE */
252 { &null_filtops }, /* EVFILT_AIO */
253 { &file_filtops }, /* EVFILT_VNODE */
254 { &proc_filtops }, /* EVFILT_PROC */
255 { &sig_filtops }, /* EVFILT_SIGNAL */
256 { &timer_filtops }, /* EVFILT_TIMER */
257 { &file_filtops }, /* EVFILT_NETDEV */
258 { &fs_filtops }, /* EVFILT_FS */
259 { &null_filtops }, /* EVFILT_LIO */
260 };
261
262 /*
263 * Simple redirection for all cdevsw style objects to call their fo_kqfilter
264 * method.
265 */
266 static int
267 filt_fileattach(struct knote *kn)
268 {
269
270 return (fo_kqfilter(kn->kn_fp, kn));
271 }
272
273 /*ARGSUSED*/
274 static int
275 kqueue_kqfilter(struct file *fp, struct knote *kn)
276 {
277 struct kqueue *kq = kn->kn_fp->f_data;
278
279 if (kn->kn_filter != EVFILT_READ)
280 return (EINVAL);
281
282 kn->kn_status |= KN_KQUEUE;
283 kn->kn_fop = &kqread_filtops;
284 knlist_add(&kq->kq_sel.si_note, kn, 0);
285
286 return (0);
287 }
288
289 static void
290 filt_kqdetach(struct knote *kn)
291 {
292 struct kqueue *kq = kn->kn_fp->f_data;
293
294 knlist_remove(&kq->kq_sel.si_note, kn, 0);
295 }
296
297 /*ARGSUSED*/
298 static int
299 filt_kqueue(struct knote *kn, long hint)
300 {
301 struct kqueue *kq = kn->kn_fp->f_data;
302
303 kn->kn_data = kq->kq_count;
304 return (kn->kn_data > 0);
305 }
306
307 /* XXX - move to kern_proc.c? */
308 static int
309 filt_procattach(struct knote *kn)
310 {
311 struct proc *p;
312 int immediate;
313 int error;
314
315 immediate = 0;
316 p = pfind(kn->kn_id);
317 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
318 p = zpfind(kn->kn_id);
319 immediate = 1;
320 } else if (p != NULL && (p->p_flag & P_WEXIT)) {
321 immediate = 1;
322 }
323
324 if (p == NULL)
325 return (ESRCH);
326 if ((error = p_cansee(curthread, p))) {
327 PROC_UNLOCK(p);
328 return (error);
329 }
330
331 kn->kn_ptr.p_proc = p;
332 kn->kn_flags |= EV_CLEAR; /* automatically set */
333
334 /*
335 * internal flag indicating registration done by kernel
336 */
337 if (kn->kn_flags & EV_FLAG1) {
338 kn->kn_data = kn->kn_sdata; /* ppid */
339 kn->kn_fflags = NOTE_CHILD;
340 kn->kn_flags &= ~EV_FLAG1;
341 }
342
343 if (immediate == 0)
344 knlist_add(&p->p_klist, kn, 1);
345
346 /*
347 * Immediately activate any exit notes if the target process is a
348 * zombie. This is necessary to handle the case where the target
349 * process, e.g. a child, dies before the kevent is registered.
350 */
351 if (immediate && filt_proc(kn, NOTE_EXIT))
352 KNOTE_ACTIVATE(kn, 0);
353
354 PROC_UNLOCK(p);
355
356 return (0);
357 }
358
359 /*
360 * The knote may be attached to a different process, which may exit,
361 * leaving nothing for the knote to be attached to. So when the process
362 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
363 * it will be deleted when read out. However, as part of the knote deletion,
364 * this routine is called, so a check is needed to avoid actually performing
365 * a detach, because the original process does not exist any more.
366 */
367 /* XXX - move to kern_proc.c? */
368 static void
369 filt_procdetach(struct knote *kn)
370 {
371 struct proc *p;
372
373 p = kn->kn_ptr.p_proc;
374 knlist_remove(&p->p_klist, kn, 0);
375 kn->kn_ptr.p_proc = NULL;
376 }
377
378 /* XXX - move to kern_proc.c? */
379 static int
380 filt_proc(struct knote *kn, long hint)
381 {
382 struct proc *p = kn->kn_ptr.p_proc;
383 u_int event;
384
385 /*
386 * mask off extra data
387 */
388 event = (u_int)hint & NOTE_PCTRLMASK;
389
390 /*
391 * if the user is interested in this event, record it.
392 */
393 if (kn->kn_sfflags & event)
394 kn->kn_fflags |= event;
395
396 /*
397 * process is gone, so flag the event as finished.
398 */
399 if (event == NOTE_EXIT) {
400 if (!(kn->kn_status & KN_DETACHED))
401 knlist_remove_inevent(&p->p_klist, kn);
402 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
403 kn->kn_data = p->p_xstat;
404 kn->kn_ptr.p_proc = NULL;
405 return (1);
406 }
407
408 return (kn->kn_fflags != 0);
409 }
410
411 /*
412 * Called when the process forked. It mostly does the same as the
413 * knote(), activating all knotes registered to be activated when the
414 * process forked. Additionally, for each knote attached to the
415 * parent, check whether user wants to track the new process. If so
416 * attach a new knote to it, and immediately report an event with the
417 * child's pid.
418 */
419 void
420 knote_fork(struct knlist *list, int pid)
421 {
422 struct kqueue *kq;
423 struct knote *kn;
424 struct kevent kev;
425 int error;
426
427 if (list == NULL)
428 return;
429 list->kl_lock(list->kl_lockarg);
430
431 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
432 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX)
433 continue;
434 kq = kn->kn_kq;
435 KQ_LOCK(kq);
436 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
437 KQ_UNLOCK(kq);
438 continue;
439 }
440
441 /*
442 * The same as knote(), activate the event.
443 */
444 if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
445 kn->kn_status |= KN_HASKQLOCK;
446 if (kn->kn_fop->f_event(kn, NOTE_FORK | pid))
447 KNOTE_ACTIVATE(kn, 1);
448 kn->kn_status &= ~KN_HASKQLOCK;
449 KQ_UNLOCK(kq);
450 continue;
451 }
452
453 /*
454 * The NOTE_TRACK case. In addition to the activation
455 * of the event, we need to register new event to
456 * track the child. Drop the locks in preparation for
457 * the call to kqueue_register().
458 */
459 kn->kn_status |= KN_INFLUX;
460 KQ_UNLOCK(kq);
461 list->kl_unlock(list->kl_lockarg);
462
463 /*
464 * Activate existing knote and register a knote with
465 * new process.
466 */
467 kev.ident = pid;
468 kev.filter = kn->kn_filter;
469 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
470 kev.fflags = kn->kn_sfflags;
471 kev.data = kn->kn_id; /* parent */
472 kev.udata = kn->kn_kevent.udata;/* preserve udata */
473 error = kqueue_register(kq, &kev, NULL, 0);
474 if (kn->kn_fop->f_event(kn, NOTE_FORK | pid))
475 KNOTE_ACTIVATE(kn, 0);
476 if (error)
477 kn->kn_fflags |= NOTE_TRACKERR;
478 KQ_LOCK(kq);
479 kn->kn_status &= ~KN_INFLUX;
480 KQ_UNLOCK_FLUX(kq);
481 list->kl_lock(list->kl_lockarg);
482 }
483 list->kl_unlock(list->kl_lockarg);
484 }
485
486 static int
487 timertoticks(intptr_t data)
488 {
489 struct timeval tv;
490 int tticks;
491
492 tv.tv_sec = data / 1000;
493 tv.tv_usec = (data % 1000) * 1000;
494 tticks = tvtohz(&tv);
495
496 return tticks;
497 }
498
499 /* XXX - move to kern_timeout.c? */
500 static void
501 filt_timerexpire(void *knx)
502 {
503 struct knote *kn = knx;
504 struct callout *calloutp;
505
506 kn->kn_data++;
507 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
508
509 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) {
510 calloutp = (struct callout *)kn->kn_hook;
511 callout_reset(calloutp, timertoticks(kn->kn_sdata),
512 filt_timerexpire, kn);
513 }
514 }
515
516 /*
517 * data contains amount of time to sleep, in milliseconds
518 */
519 /* XXX - move to kern_timeout.c? */
520 static int
521 filt_timerattach(struct knote *kn)
522 {
523 struct callout *calloutp;
524
525 atomic_add_int(&kq_ncallouts, 1);
526
527 if (kq_ncallouts >= kq_calloutmax) {
528 atomic_add_int(&kq_ncallouts, -1);
529 return (ENOMEM);
530 }
531
532 kn->kn_flags |= EV_CLEAR; /* automatically set */
533 kn->kn_status &= ~KN_DETACHED; /* knlist_add usually sets it */
534 MALLOC(calloutp, struct callout *, sizeof(*calloutp),
535 M_KQUEUE, M_WAITOK);
536 callout_init(calloutp, CALLOUT_MPSAFE);
537 kn->kn_hook = calloutp;
538 callout_reset(calloutp, timertoticks(kn->kn_sdata), filt_timerexpire,
539 kn);
540
541 return (0);
542 }
543
544 /* XXX - move to kern_timeout.c? */
545 static void
546 filt_timerdetach(struct knote *kn)
547 {
548 struct callout *calloutp;
549
550 calloutp = (struct callout *)kn->kn_hook;
551 callout_drain(calloutp);
552 FREE(calloutp, M_KQUEUE);
553 atomic_add_int(&kq_ncallouts, -1);
554 kn->kn_status |= KN_DETACHED; /* knlist_remove usually clears it */
555 }
556
557 /* XXX - move to kern_timeout.c? */
558 static int
559 filt_timer(struct knote *kn, long hint)
560 {
561
562 return (kn->kn_data != 0);
563 }
564
565 int
566 kqueue(struct thread *td, struct kqueue_args *uap)
567 {
568 struct filedesc *fdp;
569 struct kqueue *kq;
570 struct file *fp;
571 int fd, error;
572
573 fdp = td->td_proc->p_fd;
574 error = falloc(td, &fp, &fd);
575 if (error)
576 goto done2;
577
578 /* An extra reference on `nfp' has been held for us by falloc(). */
579 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
580 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK);
581 TAILQ_INIT(&kq->kq_head);
582 kq->kq_fdp = fdp;
583 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
584 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
585
586 FILEDESC_XLOCK(fdp);
587 SLIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
588 FILEDESC_XUNLOCK(fdp);
589
590 FILE_LOCK(fp);
591 fp->f_flag = FREAD | FWRITE;
592 fp->f_type = DTYPE_KQUEUE;
593 fp->f_data = kq;
594 fp->f_ops = &kqueueops;
595 FILE_UNLOCK(fp);
596 fdrop(fp, td);
597
598 td->td_retval[0] = fd;
599 done2:
600 return (error);
601 }
602
603 #ifndef _SYS_SYSPROTO_H_
604 struct kevent_args {
605 int fd;
606 const struct kevent *changelist;
607 int nchanges;
608 struct kevent *eventlist;
609 int nevents;
610 const struct timespec *timeout;
611 };
612 #endif
613 int
614 kevent(struct thread *td, struct kevent_args *uap)
615 {
616 struct timespec ts, *tsp;
617 struct kevent_copyops k_ops = { uap,
618 kevent_copyout,
619 kevent_copyin};
620 int error;
621 #ifdef KTRACE
622 struct uio ktruio;
623 struct iovec ktriov;
624 struct uio *ktruioin = NULL;
625 struct uio *ktruioout = NULL;
626 #endif
627
628 if (uap->timeout != NULL) {
629 error = copyin(uap->timeout, &ts, sizeof(ts));
630 if (error)
631 return (error);
632 tsp = &ts;
633 } else
634 tsp = NULL;
635
636 #ifdef KTRACE
637 if (KTRPOINT(td, KTR_GENIO)) {
638 ktriov.iov_base = uap->changelist;
639 ktriov.iov_len = uap->nchanges * sizeof(struct kevent);
640 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1,
641 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ,
642 .uio_td = td };
643 ktruioin = cloneuio(&ktruio);
644 ktriov.iov_base = uap->eventlist;
645 ktriov.iov_len = uap->nevents * sizeof(struct kevent);
646 ktruioout = cloneuio(&ktruio);
647 }
648 #endif
649
650 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
651 &k_ops, tsp);
652
653 #ifdef KTRACE
654 if (ktruioin != NULL) {
655 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent);
656 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0);
657 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent);
658 ktrgenio(uap->fd, UIO_READ, ktruioout, error);
659 }
660 #endif
661
662 return (error);
663 }
664
665 /*
666 * Copy 'count' items into the destination list pointed to by uap->eventlist.
667 */
668 static int
669 kevent_copyout(void *arg, struct kevent *kevp, int count)
670 {
671 struct kevent_args *uap;
672 int error;
673
674 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
675 uap = (struct kevent_args *)arg;
676
677 error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
678 if (error == 0)
679 uap->eventlist += count;
680 return (error);
681 }
682
683 /*
684 * Copy 'count' items from the list pointed to by uap->changelist.
685 */
686 static int
687 kevent_copyin(void *arg, struct kevent *kevp, int count)
688 {
689 struct kevent_args *uap;
690 int error;
691
692 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
693 uap = (struct kevent_args *)arg;
694
695 error = copyin(uap->changelist, kevp, count * sizeof *kevp);
696 if (error == 0)
697 uap->changelist += count;
698 return (error);
699 }
700
701 int
702 kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
703 struct kevent_copyops *k_ops, const struct timespec *timeout)
704 {
705 struct kevent keva[KQ_NEVENTS];
706 struct kevent *kevp, *changes;
707 struct kqueue *kq;
708 struct file *fp;
709 int i, n, nerrors, error;
710
711 if ((error = fget(td, fd, &fp)) != 0)
712 return (error);
713 if ((error = kqueue_acquire(fp, &kq)) != 0)
714 goto done_norel;
715
716 nerrors = 0;
717
718 while (nchanges > 0) {
719 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
720 error = k_ops->k_copyin(k_ops->arg, keva, n);
721 if (error)
722 goto done;
723 changes = keva;
724 for (i = 0; i < n; i++) {
725 kevp = &changes[i];
726 if (!kevp->filter)
727 continue;
728 kevp->flags &= ~EV_SYSFLAGS;
729 error = kqueue_register(kq, kevp, td, 1);
730 if (error) {
731 if (nevents != 0) {
732 kevp->flags = EV_ERROR;
733 kevp->data = error;
734 (void) k_ops->k_copyout(k_ops->arg,
735 kevp, 1);
736 nevents--;
737 nerrors++;
738 } else {
739 goto done;
740 }
741 }
742 }
743 nchanges -= n;
744 }
745 if (nerrors) {
746 td->td_retval[0] = nerrors;
747 error = 0;
748 goto done;
749 }
750
751 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td);
752 done:
753 kqueue_release(kq, 0);
754 done_norel:
755 fdrop(fp, td);
756 return (error);
757 }
758
759 int
760 kqueue_add_filteropts(int filt, struct filterops *filtops)
761 {
762 int error;
763
764 error = 0;
765 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
766 printf(
767 "trying to add a filterop that is out of range: %d is beyond %d\n",
768 ~filt, EVFILT_SYSCOUNT);
769 return EINVAL;
770 }
771 mtx_lock(&filterops_lock);
772 if (sysfilt_ops[~filt].for_fop != &null_filtops &&
773 sysfilt_ops[~filt].for_fop != NULL)
774 error = EEXIST;
775 else {
776 sysfilt_ops[~filt].for_fop = filtops;
777 sysfilt_ops[~filt].for_refcnt = 0;
778 }
779 mtx_unlock(&filterops_lock);
780
781 return (error);
782 }
783
784 int
785 kqueue_del_filteropts(int filt)
786 {
787 int error;
788
789 error = 0;
790 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
791 return EINVAL;
792
793 mtx_lock(&filterops_lock);
794 if (sysfilt_ops[~filt].for_fop == &null_filtops ||
795 sysfilt_ops[~filt].for_fop == NULL)
796 error = EINVAL;
797 else if (sysfilt_ops[~filt].for_refcnt != 0)
798 error = EBUSY;
799 else {
800 sysfilt_ops[~filt].for_fop = &null_filtops;
801 sysfilt_ops[~filt].for_refcnt = 0;
802 }
803 mtx_unlock(&filterops_lock);
804
805 return error;
806 }
807
808 static struct filterops *
809 kqueue_fo_find(int filt)
810 {
811
812 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
813 return NULL;
814
815 mtx_lock(&filterops_lock);
816 sysfilt_ops[~filt].for_refcnt++;
817 if (sysfilt_ops[~filt].for_fop == NULL)
818 sysfilt_ops[~filt].for_fop = &null_filtops;
819 mtx_unlock(&filterops_lock);
820
821 return sysfilt_ops[~filt].for_fop;
822 }
823
824 static void
825 kqueue_fo_release(int filt)
826 {
827
828 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
829 return;
830
831 mtx_lock(&filterops_lock);
832 KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
833 ("filter object refcount not valid on release"));
834 sysfilt_ops[~filt].for_refcnt--;
835 mtx_unlock(&filterops_lock);
836 }
837
838 /*
839 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will
840 * influence if memory allocation should wait. Make sure it is 0 if you
841 * hold any mutexes.
842 */
843 static int
844 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok)
845 {
846 struct filterops *fops;
847 struct file *fp;
848 struct knote *kn, *tkn;
849 int error, filt, event;
850 int haskqglobal;
851
852 fp = NULL;
853 kn = NULL;
854 error = 0;
855 haskqglobal = 0;
856
857 filt = kev->filter;
858 fops = kqueue_fo_find(filt);
859 if (fops == NULL)
860 return EINVAL;
861
862 tkn = knote_alloc(waitok); /* prevent waiting with locks */
863
864 findkn:
865 if (fops->f_isfd) {
866 KASSERT(td != NULL, ("td is NULL"));
867 error = fget(td, kev->ident, &fp);
868 if (error)
869 goto done;
870
871 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
872 kev->ident, 0) != 0) {
873 /* try again */
874 fdrop(fp, td);
875 fp = NULL;
876 error = kqueue_expand(kq, fops, kev->ident, waitok);
877 if (error)
878 goto done;
879 goto findkn;
880 }
881
882 if (fp->f_type == DTYPE_KQUEUE) {
883 /*
884 * if we add some inteligence about what we are doing,
885 * we should be able to support events on ourselves.
886 * We need to know when we are doing this to prevent
887 * getting both the knlist lock and the kq lock since
888 * they are the same thing.
889 */
890 if (fp->f_data == kq) {
891 error = EINVAL;
892 goto done;
893 }
894
895 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
896 }
897
898 KQ_LOCK(kq);
899 if (kev->ident < kq->kq_knlistsize) {
900 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
901 if (kev->filter == kn->kn_filter)
902 break;
903 }
904 } else {
905 if ((kev->flags & EV_ADD) == EV_ADD)
906 kqueue_expand(kq, fops, kev->ident, waitok);
907
908 KQ_LOCK(kq);
909 if (kq->kq_knhashmask != 0) {
910 struct klist *list;
911
912 list = &kq->kq_knhash[
913 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
914 SLIST_FOREACH(kn, list, kn_link)
915 if (kev->ident == kn->kn_id &&
916 kev->filter == kn->kn_filter)
917 break;
918 }
919 }
920
921 /* knote is in the process of changing, wait for it to stablize. */
922 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
923 if (fp != NULL) {
924 fdrop(fp, td);
925 fp = NULL;
926 }
927 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
928 kq->kq_state |= KQ_FLUXWAIT;
929 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
930 goto findkn;
931 }
932
933 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
934 KQ_UNLOCK(kq);
935 error = ENOENT;
936 goto done;
937 }
938
939 /*
940 * kn now contains the matching knote, or NULL if no match
941 */
942 if (kev->flags & EV_ADD) {
943 if (kn == NULL) {
944 kn = tkn;
945 tkn = NULL;
946 if (kn == NULL) {
947 KQ_UNLOCK(kq);
948 error = ENOMEM;
949 goto done;
950 }
951 kn->kn_fp = fp;
952 kn->kn_kq = kq;
953 kn->kn_fop = fops;
954 /*
955 * apply reference counts to knote structure, and
956 * do not release it at the end of this routine.
957 */
958 fops = NULL;
959 fp = NULL;
960
961 kn->kn_sfflags = kev->fflags;
962 kn->kn_sdata = kev->data;
963 kev->fflags = 0;
964 kev->data = 0;
965 kn->kn_kevent = *kev;
966 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
967 EV_ENABLE | EV_DISABLE);
968 kn->kn_status = KN_INFLUX|KN_DETACHED;
969
970 error = knote_attach(kn, kq);
971 KQ_UNLOCK(kq);
972 if (error != 0) {
973 tkn = kn;
974 goto done;
975 }
976
977 if ((error = kn->kn_fop->f_attach(kn)) != 0) {
978 knote_drop(kn, td);
979 goto done;
980 }
981 KN_LIST_LOCK(kn);
982 } else {
983 /*
984 * The user may change some filter values after the
985 * initial EV_ADD, but doing so will not reset any
986 * filter which has already been triggered.
987 */
988 kn->kn_status |= KN_INFLUX;
989 KQ_UNLOCK(kq);
990 KN_LIST_LOCK(kn);
991 kn->kn_sfflags = kev->fflags;
992 kn->kn_sdata = kev->data;
993 kn->kn_kevent.udata = kev->udata;
994 }
995
996 /*
997 * We can get here with kn->kn_knlist == NULL.
998 * This can happen when the initial attach event decides that
999 * the event is "completed" already. i.e. filt_procattach
1000 * is called on a zombie process. It will call filt_proc
1001 * which will remove it from the list, and NULL kn_knlist.
1002 */
1003 event = kn->kn_fop->f_event(kn, 0);
1004 KQ_LOCK(kq);
1005 if (event)
1006 KNOTE_ACTIVATE(kn, 1);
1007 kn->kn_status &= ~KN_INFLUX;
1008 KN_LIST_UNLOCK(kn);
1009 } else if (kev->flags & EV_DELETE) {
1010 kn->kn_status |= KN_INFLUX;
1011 KQ_UNLOCK(kq);
1012 if (!(kn->kn_status & KN_DETACHED))
1013 kn->kn_fop->f_detach(kn);
1014 knote_drop(kn, td);
1015 goto done;
1016 }
1017
1018 if ((kev->flags & EV_DISABLE) &&
1019 ((kn->kn_status & KN_DISABLED) == 0)) {
1020 kn->kn_status |= KN_DISABLED;
1021 }
1022
1023 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
1024 kn->kn_status &= ~KN_DISABLED;
1025 if ((kn->kn_status & KN_ACTIVE) &&
1026 ((kn->kn_status & KN_QUEUED) == 0))
1027 knote_enqueue(kn);
1028 }
1029 KQ_UNLOCK_FLUX(kq);
1030
1031 done:
1032 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1033 if (fp != NULL)
1034 fdrop(fp, td);
1035 if (tkn != NULL)
1036 knote_free(tkn);
1037 if (fops != NULL)
1038 kqueue_fo_release(filt);
1039 return (error);
1040 }
1041
1042 static int
1043 kqueue_acquire(struct file *fp, struct kqueue **kqp)
1044 {
1045 int error;
1046 struct kqueue *kq;
1047
1048 error = 0;
1049
1050 FILE_LOCK(fp);
1051 do {
1052 kq = fp->f_data;
1053 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) {
1054 error = EBADF;
1055 break;
1056 }
1057 *kqp = kq;
1058 KQ_LOCK(kq);
1059 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
1060 KQ_UNLOCK(kq);
1061 error = EBADF;
1062 break;
1063 }
1064 kq->kq_refcnt++;
1065 KQ_UNLOCK(kq);
1066 } while (0);
1067 FILE_UNLOCK(fp);
1068
1069 return error;
1070 }
1071
1072 static void
1073 kqueue_release(struct kqueue *kq, int locked)
1074 {
1075 if (locked)
1076 KQ_OWNED(kq);
1077 else
1078 KQ_LOCK(kq);
1079 kq->kq_refcnt--;
1080 if (kq->kq_refcnt == 1)
1081 wakeup(&kq->kq_refcnt);
1082 if (!locked)
1083 KQ_UNLOCK(kq);
1084 }
1085
1086 static void
1087 kqueue_schedtask(struct kqueue *kq)
1088 {
1089
1090 KQ_OWNED(kq);
1091 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
1092 ("scheduling kqueue task while draining"));
1093
1094 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
1095 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task);
1096 kq->kq_state |= KQ_TASKSCHED;
1097 }
1098 }
1099
1100 /*
1101 * Expand the kq to make sure we have storage for fops/ident pair.
1102 *
1103 * Return 0 on success (or no work necessary), return errno on failure.
1104 *
1105 * Not calling hashinit w/ waitok (proper malloc flag) should be safe.
1106 * If kqueue_register is called from a non-fd context, there usually/should
1107 * be no locks held.
1108 */
1109 static int
1110 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident,
1111 int waitok)
1112 {
1113 struct klist *list, *tmp_knhash, *to_free;
1114 u_long tmp_knhashmask;
1115 int size;
1116 int fd;
1117 int mflag = waitok ? M_WAITOK : M_NOWAIT;
1118
1119 KQ_NOTOWNED(kq);
1120
1121 to_free = NULL;
1122 if (fops->f_isfd) {
1123 fd = ident;
1124 if (kq->kq_knlistsize <= fd) {
1125 size = kq->kq_knlistsize;
1126 while (size <= fd)
1127 size += KQEXTENT;
1128 MALLOC(list, struct klist *,
1129 size * sizeof list, M_KQUEUE, mflag);
1130 if (list == NULL)
1131 return ENOMEM;
1132 KQ_LOCK(kq);
1133 if (kq->kq_knlistsize > fd) {
1134 to_free = list;
1135 list = NULL;
1136 } else {
1137 if (kq->kq_knlist != NULL) {
1138 bcopy(kq->kq_knlist, list,
1139 kq->kq_knlistsize * sizeof list);
1140 to_free = kq->kq_knlist;
1141 kq->kq_knlist = NULL;
1142 }
1143 bzero((caddr_t)list +
1144 kq->kq_knlistsize * sizeof list,
1145 (size - kq->kq_knlistsize) * sizeof list);
1146 kq->kq_knlistsize = size;
1147 kq->kq_knlist = list;
1148 }
1149 KQ_UNLOCK(kq);
1150 }
1151 } else {
1152 if (kq->kq_knhashmask == 0) {
1153 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
1154 &tmp_knhashmask);
1155 if (tmp_knhash == NULL)
1156 return ENOMEM;
1157 KQ_LOCK(kq);
1158 if (kq->kq_knhashmask == 0) {
1159 kq->kq_knhash = tmp_knhash;
1160 kq->kq_knhashmask = tmp_knhashmask;
1161 } else {
1162 to_free = tmp_knhash;
1163 }
1164 KQ_UNLOCK(kq);
1165 }
1166 }
1167 free(to_free, M_KQUEUE);
1168
1169 KQ_NOTOWNED(kq);
1170 return 0;
1171 }
1172
1173 static void
1174 kqueue_task(void *arg, int pending)
1175 {
1176 struct kqueue *kq;
1177 int haskqglobal;
1178
1179 haskqglobal = 0;
1180 kq = arg;
1181
1182 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1183 KQ_LOCK(kq);
1184
1185 KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
1186
1187 kq->kq_state &= ~KQ_TASKSCHED;
1188 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
1189 wakeup(&kq->kq_state);
1190 }
1191 KQ_UNLOCK(kq);
1192 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1193 }
1194
1195 /*
1196 * Scan, update kn_data (if not ONESHOT), and copyout triggered events.
1197 * We treat KN_MARKER knotes as if they are INFLUX.
1198 */
1199 static int
1200 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
1201 const struct timespec *tsp, struct kevent *keva, struct thread *td)
1202 {
1203 struct kevent *kevp;
1204 struct timeval atv, rtv, ttv;
1205 struct knote *kn, *marker;
1206 int count, timeout, nkev, error, influx;
1207 int haskqglobal;
1208
1209 count = maxevents;
1210 nkev = 0;
1211 error = 0;
1212 haskqglobal = 0;
1213
1214 if (maxevents == 0)
1215 goto done_nl;
1216
1217 if (tsp != NULL) {
1218 TIMESPEC_TO_TIMEVAL(&atv, tsp);
1219 if (itimerfix(&atv)) {
1220 error = EINVAL;
1221 goto done_nl;
1222 }
1223 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
1224 timeout = -1;
1225 else
1226 timeout = atv.tv_sec > 24 * 60 * 60 ?
1227 24 * 60 * 60 * hz : tvtohz(&atv);
1228 getmicrouptime(&rtv);
1229 timevaladd(&atv, &rtv);
1230 } else {
1231 atv.tv_sec = 0;
1232 atv.tv_usec = 0;
1233 timeout = 0;
1234 }
1235 marker = knote_alloc(1);
1236 if (marker == NULL) {
1237 error = ENOMEM;
1238 goto done_nl;
1239 }
1240 marker->kn_status = KN_MARKER;
1241 KQ_LOCK(kq);
1242 goto start;
1243
1244 retry:
1245 if (atv.tv_sec || atv.tv_usec) {
1246 getmicrouptime(&rtv);
1247 if (timevalcmp(&rtv, &atv, >=))
1248 goto done;
1249 ttv = atv;
1250 timevalsub(&ttv, &rtv);
1251 timeout = ttv.tv_sec > 24 * 60 * 60 ?
1252 24 * 60 * 60 * hz : tvtohz(&ttv);
1253 }
1254
1255 start:
1256 kevp = keva;
1257 if (kq->kq_count == 0) {
1258 if (timeout < 0) {
1259 error = EWOULDBLOCK;
1260 } else {
1261 kq->kq_state |= KQ_SLEEP;
1262 error = msleep(kq, &kq->kq_lock, PSOCK | PCATCH,
1263 "kqread", timeout);
1264 }
1265 if (error == 0)
1266 goto retry;
1267 /* don't restart after signals... */
1268 if (error == ERESTART)
1269 error = EINTR;
1270 else if (error == EWOULDBLOCK)
1271 error = 0;
1272 goto done;
1273 }
1274
1275 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
1276 influx = 0;
1277 while (count) {
1278 KQ_OWNED(kq);
1279 kn = TAILQ_FIRST(&kq->kq_head);
1280
1281 if ((kn->kn_status == KN_MARKER && kn != marker) ||
1282 (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1283 if (influx) {
1284 influx = 0;
1285 KQ_FLUX_WAKEUP(kq);
1286 }
1287 kq->kq_state |= KQ_FLUXWAIT;
1288 error = msleep(kq, &kq->kq_lock, PSOCK,
1289 "kqflxwt", 0);
1290 continue;
1291 }
1292
1293 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
1294 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
1295 kn->kn_status &= ~KN_QUEUED;
1296 kq->kq_count--;
1297 continue;
1298 }
1299 if (kn == marker) {
1300 KQ_FLUX_WAKEUP(kq);
1301 if (count == maxevents)
1302 goto retry;
1303 goto done;
1304 }
1305 KASSERT((kn->kn_status & KN_INFLUX) == 0,
1306 ("KN_INFLUX set when not suppose to be"));
1307
1308 if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
1309 kn->kn_status &= ~KN_QUEUED;
1310 kn->kn_status |= KN_INFLUX;
1311 kq->kq_count--;
1312 KQ_UNLOCK(kq);
1313 /*
1314 * We don't need to lock the list since we've marked
1315 * it _INFLUX.
1316 */
1317 *kevp = kn->kn_kevent;
1318 if (!(kn->kn_status & KN_DETACHED))
1319 kn->kn_fop->f_detach(kn);
1320 knote_drop(kn, td);
1321 KQ_LOCK(kq);
1322 kn = NULL;
1323 } else {
1324 kn->kn_status |= KN_INFLUX;
1325 KQ_UNLOCK(kq);
1326 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
1327 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1328 KN_LIST_LOCK(kn);
1329 if (kn->kn_fop->f_event(kn, 0) == 0) {
1330 KQ_LOCK(kq);
1331 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1332 kn->kn_status &=
1333 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX);
1334 kq->kq_count--;
1335 KN_LIST_UNLOCK(kn);
1336 influx = 1;
1337 continue;
1338 }
1339 *kevp = kn->kn_kevent;
1340 KQ_LOCK(kq);
1341 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1342 if (kn->kn_flags & EV_CLEAR) {
1343 kn->kn_data = 0;
1344 kn->kn_fflags = 0;
1345 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
1346 kq->kq_count--;
1347 } else
1348 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
1349
1350 kn->kn_status &= ~(KN_INFLUX);
1351 KN_LIST_UNLOCK(kn);
1352 influx = 1;
1353 }
1354
1355 /* we are returning a copy to the user */
1356 kevp++;
1357 nkev++;
1358 count--;
1359
1360 if (nkev == KQ_NEVENTS) {
1361 influx = 0;
1362 KQ_UNLOCK_FLUX(kq);
1363 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1364 nkev = 0;
1365 kevp = keva;
1366 KQ_LOCK(kq);
1367 if (error)
1368 break;
1369 }
1370 }
1371 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
1372 done:
1373 KQ_OWNED(kq);
1374 KQ_UNLOCK_FLUX(kq);
1375 knote_free(marker);
1376 done_nl:
1377 KQ_NOTOWNED(kq);
1378 if (nkev != 0)
1379 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1380 td->td_retval[0] = maxevents - count;
1381 return (error);
1382 }
1383
1384 /*
1385 * XXX
1386 * This could be expanded to call kqueue_scan, if desired.
1387 */
1388 /*ARGSUSED*/
1389 static int
1390 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
1391 int flags, struct thread *td)
1392 {
1393 return (ENXIO);
1394 }
1395
1396 /*ARGSUSED*/
1397 static int
1398 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
1399 int flags, struct thread *td)
1400 {
1401 return (ENXIO);
1402 }
1403
1404 /*ARGSUSED*/
1405 static int
1406 kqueue_ioctl(struct file *fp, u_long cmd, void *data,
1407 struct ucred *active_cred, struct thread *td)
1408 {
1409 /*
1410 * Enabling sigio causes two major problems:
1411 * 1) infinite recursion:
1412 * Synopsys: kevent is being used to track signals and have FIOASYNC
1413 * set. On receipt of a signal this will cause a kqueue to recurse
1414 * into itself over and over. Sending the sigio causes the kqueue
1415 * to become ready, which in turn posts sigio again, forever.
1416 * Solution: this can be solved by setting a flag in the kqueue that
1417 * we have a SIGIO in progress.
1418 * 2) locking problems:
1419 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
1420 * us above the proc and pgrp locks.
1421 * Solution: Post a signal using an async mechanism, being sure to
1422 * record a generation count in the delivery so that we do not deliver
1423 * a signal to the wrong process.
1424 *
1425 * Note, these two mechanisms are somewhat mutually exclusive!
1426 */
1427 #if 0
1428 struct kqueue *kq;
1429
1430 kq = fp->f_data;
1431 switch (cmd) {
1432 case FIOASYNC:
1433 if (*(int *)data) {
1434 kq->kq_state |= KQ_ASYNC;
1435 } else {
1436 kq->kq_state &= ~KQ_ASYNC;
1437 }
1438 return (0);
1439
1440 case FIOSETOWN:
1441 return (fsetown(*(int *)data, &kq->kq_sigio));
1442
1443 case FIOGETOWN:
1444 *(int *)data = fgetown(&kq->kq_sigio);
1445 return (0);
1446 }
1447 #endif
1448
1449 return (ENOTTY);
1450 }
1451
1452 /*ARGSUSED*/
1453 static int
1454 kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
1455 struct thread *td)
1456 {
1457 struct kqueue *kq;
1458 int revents = 0;
1459 int error;
1460
1461 if ((error = kqueue_acquire(fp, &kq)))
1462 return POLLERR;
1463
1464 KQ_LOCK(kq);
1465 if (events & (POLLIN | POLLRDNORM)) {
1466 if (kq->kq_count) {
1467 revents |= events & (POLLIN | POLLRDNORM);
1468 } else {
1469 selrecord(td, &kq->kq_sel);
1470 kq->kq_state |= KQ_SEL;
1471 }
1472 }
1473 kqueue_release(kq, 1);
1474 KQ_UNLOCK(kq);
1475 return (revents);
1476 }
1477
1478 /*ARGSUSED*/
1479 static int
1480 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
1481 struct thread *td)
1482 {
1483
1484 bzero((void *)st, sizeof *st);
1485 /*
1486 * We no longer return kq_count because the unlocked value is useless.
1487 * If you spent all this time getting the count, why not spend your
1488 * syscall better by calling kevent?
1489 *
1490 * XXX - This is needed for libc_r.
1491 */
1492 st->st_mode = S_IFIFO;
1493 return (0);
1494 }
1495
1496 /*ARGSUSED*/
1497 static int
1498 kqueue_close(struct file *fp, struct thread *td)
1499 {
1500 struct kqueue *kq = fp->f_data;
1501 struct filedesc *fdp;
1502 struct knote *kn;
1503 int i;
1504 int error;
1505
1506 if ((error = kqueue_acquire(fp, &kq)))
1507 return error;
1508
1509 KQ_LOCK(kq);
1510
1511 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
1512 ("kqueue already closing"));
1513 kq->kq_state |= KQ_CLOSING;
1514 if (kq->kq_refcnt > 1)
1515 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
1516
1517 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
1518 fdp = kq->kq_fdp;
1519
1520 KASSERT(knlist_empty(&kq->kq_sel.si_note),
1521 ("kqueue's knlist not empty"));
1522
1523 for (i = 0; i < kq->kq_knlistsize; i++) {
1524 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
1525 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1526 kq->kq_state |= KQ_FLUXWAIT;
1527 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
1528 continue;
1529 }
1530 kn->kn_status |= KN_INFLUX;
1531 KQ_UNLOCK(kq);
1532 if (!(kn->kn_status & KN_DETACHED))
1533 kn->kn_fop->f_detach(kn);
1534 knote_drop(kn, td);
1535 KQ_LOCK(kq);
1536 }
1537 }
1538 if (kq->kq_knhashmask != 0) {
1539 for (i = 0; i <= kq->kq_knhashmask; i++) {
1540 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
1541 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1542 kq->kq_state |= KQ_FLUXWAIT;
1543 msleep(kq, &kq->kq_lock, PSOCK,
1544 "kqclo2", 0);
1545 continue;
1546 }
1547 kn->kn_status |= KN_INFLUX;
1548 KQ_UNLOCK(kq);
1549 if (!(kn->kn_status & KN_DETACHED))
1550 kn->kn_fop->f_detach(kn);
1551 knote_drop(kn, td);
1552 KQ_LOCK(kq);
1553 }
1554 }
1555 }
1556
1557 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
1558 kq->kq_state |= KQ_TASKDRAIN;
1559 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
1560 }
1561
1562 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
1563 kq->kq_state &= ~KQ_SEL;
1564 selwakeuppri(&kq->kq_sel, PSOCK);
1565 }
1566
1567 KQ_UNLOCK(kq);
1568
1569 FILEDESC_XLOCK(fdp);
1570 SLIST_REMOVE(&fdp->fd_kqlist, kq, kqueue, kq_list);
1571 FILEDESC_XUNLOCK(fdp);
1572
1573 knlist_destroy(&kq->kq_sel.si_note);
1574 mtx_destroy(&kq->kq_lock);
1575 kq->kq_fdp = NULL;
1576
1577 if (kq->kq_knhash != NULL)
1578 free(kq->kq_knhash, M_KQUEUE);
1579 if (kq->kq_knlist != NULL)
1580 free(kq->kq_knlist, M_KQUEUE);
1581
1582 funsetown(&kq->kq_sigio);
1583 free(kq, M_KQUEUE);
1584 fp->f_data = NULL;
1585
1586 return (0);
1587 }
1588
1589 static void
1590 kqueue_wakeup(struct kqueue *kq)
1591 {
1592 KQ_OWNED(kq);
1593
1594 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
1595 kq->kq_state &= ~KQ_SLEEP;
1596 wakeup(kq);
1597 }
1598 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
1599 kq->kq_state &= ~KQ_SEL;
1600 selwakeuppri(&kq->kq_sel, PSOCK);
1601 }
1602 if (!knlist_empty(&kq->kq_sel.si_note))
1603 kqueue_schedtask(kq);
1604 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
1605 pgsigio(&kq->kq_sigio, SIGIO, 0);
1606 }
1607 }
1608
1609 /*
1610 * Walk down a list of knotes, activating them if their event has triggered.
1611 *
1612 * There is a possibility to optimize in the case of one kq watching another.
1613 * Instead of scheduling a task to wake it up, you could pass enough state
1614 * down the chain to make up the parent kqueue. Make this code functional
1615 * first.
1616 */
1617 void
1618 knote(struct knlist *list, long hint, int lockflags)
1619 {
1620 struct kqueue *kq;
1621 struct knote *kn;
1622 int error;
1623
1624 if (list == NULL)
1625 return;
1626
1627 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
1628
1629 if ((lockflags & KNF_LISTLOCKED) == 0)
1630 list->kl_lock(list->kl_lockarg);
1631
1632 /*
1633 * If we unlock the list lock (and set KN_INFLUX), we can eliminate
1634 * the kqueue scheduling, but this will introduce four
1635 * lock/unlock's for each knote to test. If we do, continue to use
1636 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is
1637 * only safe if you want to remove the current item, which we are
1638 * not doing.
1639 */
1640 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
1641 kq = kn->kn_kq;
1642 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) {
1643 KQ_LOCK(kq);
1644 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1645 KQ_UNLOCK(kq);
1646 } else if ((lockflags & KNF_NOKQLOCK) != 0) {
1647 kn->kn_status |= KN_INFLUX;
1648 KQ_UNLOCK(kq);
1649 error = kn->kn_fop->f_event(kn, hint);
1650 KQ_LOCK(kq);
1651 kn->kn_status &= ~KN_INFLUX;
1652 if (error)
1653 KNOTE_ACTIVATE(kn, 1);
1654 KQ_UNLOCK_FLUX(kq);
1655 } else {
1656 kn->kn_status |= KN_HASKQLOCK;
1657 if (kn->kn_fop->f_event(kn, hint))
1658 KNOTE_ACTIVATE(kn, 1);
1659 kn->kn_status &= ~KN_HASKQLOCK;
1660 KQ_UNLOCK(kq);
1661 }
1662 }
1663 kq = NULL;
1664 }
1665 if ((lockflags & KNF_LISTLOCKED) == 0)
1666 list->kl_unlock(list->kl_lockarg);
1667 }
1668
1669 /*
1670 * add a knote to a knlist
1671 */
1672 void
1673 knlist_add(struct knlist *knl, struct knote *kn, int islocked)
1674 {
1675 KNL_ASSERT_LOCK(knl, islocked);
1676 KQ_NOTOWNED(kn->kn_kq);
1677 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) ==
1678 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED"));
1679 if (!islocked)
1680 knl->kl_lock(knl->kl_lockarg);
1681 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext);
1682 if (!islocked)
1683 knl->kl_unlock(knl->kl_lockarg);
1684 KQ_LOCK(kn->kn_kq);
1685 kn->kn_knlist = knl;
1686 kn->kn_status &= ~KN_DETACHED;
1687 KQ_UNLOCK(kn->kn_kq);
1688 }
1689
1690 static void
1691 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked)
1692 {
1693 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked"));
1694 KNL_ASSERT_LOCK(knl, knlislocked);
1695 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED);
1696 if (!kqislocked)
1697 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX,
1698 ("knlist_remove called w/o knote being KN_INFLUX or already removed"));
1699 if (!knlislocked)
1700 knl->kl_lock(knl->kl_lockarg);
1701 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
1702 kn->kn_knlist = NULL;
1703 if (!knlislocked)
1704 knl->kl_unlock(knl->kl_lockarg);
1705 if (!kqislocked)
1706 KQ_LOCK(kn->kn_kq);
1707 kn->kn_status |= KN_DETACHED;
1708 if (!kqislocked)
1709 KQ_UNLOCK(kn->kn_kq);
1710 }
1711
1712 /*
1713 * remove all knotes from a specified klist
1714 */
1715 void
1716 knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
1717 {
1718
1719 knlist_remove_kq(knl, kn, islocked, 0);
1720 }
1721
1722 /*
1723 * remove knote from a specified klist while in f_event handler.
1724 */
1725 void
1726 knlist_remove_inevent(struct knlist *knl, struct knote *kn)
1727 {
1728
1729 knlist_remove_kq(knl, kn, 1,
1730 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK);
1731 }
1732
1733 int
1734 knlist_empty(struct knlist *knl)
1735 {
1736 KNL_ASSERT_LOCKED(knl);
1737 return SLIST_EMPTY(&knl->kl_list);
1738 }
1739
1740 static struct mtx knlist_lock;
1741 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects",
1742 MTX_DEF);
1743 static void knlist_mtx_lock(void *arg);
1744 static void knlist_mtx_unlock(void *arg);
1745 static int knlist_mtx_locked(void *arg);
1746
1747 static void
1748 knlist_mtx_lock(void *arg)
1749 {
1750 mtx_lock((struct mtx *)arg);
1751 }
1752
1753 static void
1754 knlist_mtx_unlock(void *arg)
1755 {
1756 mtx_unlock((struct mtx *)arg);
1757 }
1758
1759 static int
1760 knlist_mtx_locked(void *arg)
1761 {
1762 return (mtx_owned((struct mtx *)arg));
1763 }
1764
1765 void
1766 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
1767 void (*kl_unlock)(void *), int (*kl_locked)(void *))
1768 {
1769
1770 if (lock == NULL)
1771 knl->kl_lockarg = &knlist_lock;
1772 else
1773 knl->kl_lockarg = lock;
1774
1775 if (kl_lock == NULL)
1776 knl->kl_lock = knlist_mtx_lock;
1777 else
1778 knl->kl_lock = kl_lock;
1779 if (kl_unlock == NULL)
1780 knl->kl_unlock = knlist_mtx_unlock;
1781 else
1782 knl->kl_unlock = kl_unlock;
1783 if (kl_locked == NULL && kl_lock == NULL && kl_unlock == NULL)
1784 knl->kl_locked = knlist_mtx_locked;
1785 else
1786 knl->kl_locked = kl_locked;
1787
1788 SLIST_INIT(&knl->kl_list);
1789 }
1790
1791 void
1792 knlist_init_mtx(struct knlist *knl, struct mtx *lock)
1793 {
1794
1795 knlist_init(knl, lock, NULL, NULL, NULL);
1796 }
1797
1798 void
1799 knlist_destroy(struct knlist *knl)
1800 {
1801
1802 #ifdef INVARIANTS
1803 /*
1804 * if we run across this error, we need to find the offending
1805 * driver and have it call knlist_clear.
1806 */
1807 if (!SLIST_EMPTY(&knl->kl_list))
1808 printf("WARNING: destroying knlist w/ knotes on it!\n");
1809 #endif
1810
1811 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL;
1812 SLIST_INIT(&knl->kl_list);
1813 }
1814
1815 /*
1816 * Even if we are locked, we may need to drop the lock to allow any influx
1817 * knotes time to "settle".
1818 */
1819 void
1820 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
1821 {
1822 struct knote *kn, *kn2;
1823 struct kqueue *kq;
1824
1825 if (islocked)
1826 KNL_ASSERT_LOCKED(knl);
1827 else {
1828 KNL_ASSERT_UNLOCKED(knl);
1829 again: /* need to reacquire lock since we have dropped it */
1830 knl->kl_lock(knl->kl_lockarg);
1831 }
1832
1833 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
1834 kq = kn->kn_kq;
1835 KQ_LOCK(kq);
1836 if ((kn->kn_status & KN_INFLUX)) {
1837 KQ_UNLOCK(kq);
1838 continue;
1839 }
1840 knlist_remove_kq(knl, kn, 1, 1);
1841 if (killkn) {
1842 kn->kn_status |= KN_INFLUX | KN_DETACHED;
1843 KQ_UNLOCK(kq);
1844 knote_drop(kn, td);
1845 } else {
1846 /* Make sure cleared knotes disappear soon */
1847 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
1848 KQ_UNLOCK(kq);
1849 }
1850 kq = NULL;
1851 }
1852
1853 if (!SLIST_EMPTY(&knl->kl_list)) {
1854 /* there are still KN_INFLUX remaining */
1855 kn = SLIST_FIRST(&knl->kl_list);
1856 kq = kn->kn_kq;
1857 KQ_LOCK(kq);
1858 KASSERT(kn->kn_status & KN_INFLUX,
1859 ("knote removed w/o list lock"));
1860 knl->kl_unlock(knl->kl_lockarg);
1861 kq->kq_state |= KQ_FLUXWAIT;
1862 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
1863 kq = NULL;
1864 goto again;
1865 }
1866
1867 if (islocked)
1868 KNL_ASSERT_LOCKED(knl);
1869 else {
1870 knl->kl_unlock(knl->kl_lockarg);
1871 KNL_ASSERT_UNLOCKED(knl);
1872 }
1873 }
1874
1875 /*
1876 * Remove all knotes referencing a specified fd must be called with FILEDESC
1877 * lock. This prevents a race where a new fd comes along and occupies the
1878 * entry and we attach a knote to the fd.
1879 */
1880 void
1881 knote_fdclose(struct thread *td, int fd)
1882 {
1883 struct filedesc *fdp = td->td_proc->p_fd;
1884 struct kqueue *kq;
1885 struct knote *kn;
1886 int influx;
1887
1888 FILEDESC_XLOCK_ASSERT(fdp);
1889
1890 /*
1891 * We shouldn't have to worry about new kevents appearing on fd
1892 * since filedesc is locked.
1893 */
1894 SLIST_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
1895 KQ_LOCK(kq);
1896
1897 again:
1898 influx = 0;
1899 while (kq->kq_knlistsize > fd &&
1900 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
1901 if (kn->kn_status & KN_INFLUX) {
1902 /* someone else might be waiting on our knote */
1903 if (influx)
1904 wakeup(kq);
1905 kq->kq_state |= KQ_FLUXWAIT;
1906 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
1907 goto again;
1908 }
1909 kn->kn_status |= KN_INFLUX;
1910 KQ_UNLOCK(kq);
1911 if (!(kn->kn_status & KN_DETACHED))
1912 kn->kn_fop->f_detach(kn);
1913 knote_drop(kn, td);
1914 influx = 1;
1915 KQ_LOCK(kq);
1916 }
1917 KQ_UNLOCK_FLUX(kq);
1918 }
1919 }
1920
1921 static int
1922 knote_attach(struct knote *kn, struct kqueue *kq)
1923 {
1924 struct klist *list;
1925
1926 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX"));
1927 KQ_OWNED(kq);
1928
1929 if (kn->kn_fop->f_isfd) {
1930 if (kn->kn_id >= kq->kq_knlistsize)
1931 return ENOMEM;
1932 list = &kq->kq_knlist[kn->kn_id];
1933 } else {
1934 if (kq->kq_knhash == NULL)
1935 return ENOMEM;
1936 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
1937 }
1938
1939 SLIST_INSERT_HEAD(list, kn, kn_link);
1940
1941 return 0;
1942 }
1943
1944 /*
1945 * knote must already have been detached using the f_detach method.
1946 * no lock need to be held, it is assumed that the KN_INFLUX flag is set
1947 * to prevent other removal.
1948 */
1949 static void
1950 knote_drop(struct knote *kn, struct thread *td)
1951 {
1952 struct kqueue *kq;
1953 struct klist *list;
1954
1955 kq = kn->kn_kq;
1956
1957 KQ_NOTOWNED(kq);
1958 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX,
1959 ("knote_drop called without KN_INFLUX set in kn_status"));
1960
1961 KQ_LOCK(kq);
1962 if (kn->kn_fop->f_isfd)
1963 list = &kq->kq_knlist[kn->kn_id];
1964 else
1965 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
1966
1967 if (!SLIST_EMPTY(list))
1968 SLIST_REMOVE(list, kn, knote, kn_link);
1969 if (kn->kn_status & KN_QUEUED)
1970 knote_dequeue(kn);
1971 KQ_UNLOCK_FLUX(kq);
1972
1973 if (kn->kn_fop->f_isfd) {
1974 fdrop(kn->kn_fp, td);
1975 kn->kn_fp = NULL;
1976 }
1977 kqueue_fo_release(kn->kn_kevent.filter);
1978 kn->kn_fop = NULL;
1979 knote_free(kn);
1980 }
1981
1982 static void
1983 knote_enqueue(struct knote *kn)
1984 {
1985 struct kqueue *kq = kn->kn_kq;
1986
1987 KQ_OWNED(kn->kn_kq);
1988 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
1989
1990 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
1991 kn->kn_status |= KN_QUEUED;
1992 kq->kq_count++;
1993 kqueue_wakeup(kq);
1994 }
1995
1996 static void
1997 knote_dequeue(struct knote *kn)
1998 {
1999 struct kqueue *kq = kn->kn_kq;
2000
2001 KQ_OWNED(kn->kn_kq);
2002 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
2003
2004 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
2005 kn->kn_status &= ~KN_QUEUED;
2006 kq->kq_count--;
2007 }
2008
2009 static void
2010 knote_init(void)
2011 {
2012
2013 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
2014 NULL, NULL, UMA_ALIGN_PTR, 0);
2015 }
2016 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
2017
2018 static struct knote *
2019 knote_alloc(int waitok)
2020 {
2021 return ((struct knote *)uma_zalloc(knote_zone,
2022 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO));
2023 }
2024
2025 static void
2026 knote_free(struct knote *kn)
2027 {
2028 if (kn != NULL)
2029 uma_zfree(knote_zone, kn);
2030 }
2031
2032 /*
2033 * Register the kev w/ the kq specified by fd.
2034 */
2035 int
2036 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok)
2037 {
2038 struct kqueue *kq;
2039 struct file *fp;
2040 int error;
2041
2042 if ((error = fget(td, fd, &fp)) != 0)
2043 return (error);
2044 if ((error = kqueue_acquire(fp, &kq)) != 0)
2045 goto noacquire;
2046
2047 error = kqueue_register(kq, kev, td, waitok);
2048
2049 kqueue_release(kq, 0);
2050
2051 noacquire:
2052 fdrop(fp, td);
2053
2054 return error;
2055 }
Cache object: 7197a0c2a9724a001b27cac121a9e86a
|