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 * Copyright (c) 2009 Apple, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD: releng/9.0/sys/kern/kern_event.c 225617 2011-09-16 13:58:51Z kmacy $");
31
32 #include "opt_ktrace.h"
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/capability.h>
37 #include <sys/kernel.h>
38 #include <sys/lock.h>
39 #include <sys/mutex.h>
40 #include <sys/proc.h>
41 #include <sys/malloc.h>
42 #include <sys/unistd.h>
43 #include <sys/file.h>
44 #include <sys/filedesc.h>
45 #include <sys/filio.h>
46 #include <sys/fcntl.h>
47 #include <sys/kthread.h>
48 #include <sys/selinfo.h>
49 #include <sys/queue.h>
50 #include <sys/event.h>
51 #include <sys/eventvar.h>
52 #include <sys/poll.h>
53 #include <sys/protosw.h>
54 #include <sys/sigio.h>
55 #include <sys/signalvar.h>
56 #include <sys/socket.h>
57 #include <sys/socketvar.h>
58 #include <sys/stat.h>
59 #include <sys/sysctl.h>
60 #include <sys/sysproto.h>
61 #include <sys/syscallsubr.h>
62 #include <sys/taskqueue.h>
63 #include <sys/uio.h>
64 #ifdef KTRACE
65 #include <sys/ktrace.h>
66 #endif
67
68 #include <vm/uma.h>
69
70 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
71
72 /*
73 * This lock is used if multiple kq locks are required. This possibly
74 * should be made into a per proc lock.
75 */
76 static struct mtx kq_global;
77 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF);
78 #define KQ_GLOBAL_LOCK(lck, haslck) do { \
79 if (!haslck) \
80 mtx_lock(lck); \
81 haslck = 1; \
82 } while (0)
83 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \
84 if (haslck) \
85 mtx_unlock(lck); \
86 haslck = 0; \
87 } while (0)
88
89 TASKQUEUE_DEFINE_THREAD(kqueue);
90
91 static int kevent_copyout(void *arg, struct kevent *kevp, int count);
92 static int kevent_copyin(void *arg, struct kevent *kevp, int count);
93 static int kqueue_register(struct kqueue *kq, struct kevent *kev,
94 struct thread *td, int waitok);
95 static int kqueue_acquire(struct file *fp, struct kqueue **kqp);
96 static void kqueue_release(struct kqueue *kq, int locked);
97 static int kqueue_expand(struct kqueue *kq, struct filterops *fops,
98 uintptr_t ident, int waitok);
99 static void kqueue_task(void *arg, int pending);
100 static int kqueue_scan(struct kqueue *kq, int maxevents,
101 struct kevent_copyops *k_ops,
102 const struct timespec *timeout,
103 struct kevent *keva, struct thread *td);
104 static void kqueue_wakeup(struct kqueue *kq);
105 static struct filterops *kqueue_fo_find(int filt);
106 static void kqueue_fo_release(int filt);
107
108 static fo_rdwr_t kqueue_read;
109 static fo_rdwr_t kqueue_write;
110 static fo_truncate_t kqueue_truncate;
111 static fo_ioctl_t kqueue_ioctl;
112 static fo_poll_t kqueue_poll;
113 static fo_kqfilter_t kqueue_kqfilter;
114 static fo_stat_t kqueue_stat;
115 static fo_close_t kqueue_close;
116
117 static struct fileops kqueueops = {
118 .fo_read = kqueue_read,
119 .fo_write = kqueue_write,
120 .fo_truncate = kqueue_truncate,
121 .fo_ioctl = kqueue_ioctl,
122 .fo_poll = kqueue_poll,
123 .fo_kqfilter = kqueue_kqfilter,
124 .fo_stat = kqueue_stat,
125 .fo_close = kqueue_close,
126 .fo_chmod = invfo_chmod,
127 .fo_chown = invfo_chown,
128 };
129
130 static int knote_attach(struct knote *kn, struct kqueue *kq);
131 static void knote_drop(struct knote *kn, struct thread *td);
132 static void knote_enqueue(struct knote *kn);
133 static void knote_dequeue(struct knote *kn);
134 static void knote_init(void);
135 static struct knote *knote_alloc(int waitok);
136 static void knote_free(struct knote *kn);
137
138 static void filt_kqdetach(struct knote *kn);
139 static int filt_kqueue(struct knote *kn, long hint);
140 static int filt_procattach(struct knote *kn);
141 static void filt_procdetach(struct knote *kn);
142 static int filt_proc(struct knote *kn, long hint);
143 static int filt_fileattach(struct knote *kn);
144 static void filt_timerexpire(void *knx);
145 static int filt_timerattach(struct knote *kn);
146 static void filt_timerdetach(struct knote *kn);
147 static int filt_timer(struct knote *kn, long hint);
148 static int filt_userattach(struct knote *kn);
149 static void filt_userdetach(struct knote *kn);
150 static int filt_user(struct knote *kn, long hint);
151 static void filt_usertouch(struct knote *kn, struct kevent *kev,
152 u_long type);
153
154 static struct filterops file_filtops = {
155 .f_isfd = 1,
156 .f_attach = filt_fileattach,
157 };
158 static struct filterops kqread_filtops = {
159 .f_isfd = 1,
160 .f_detach = filt_kqdetach,
161 .f_event = filt_kqueue,
162 };
163 /* XXX - move to kern_proc.c? */
164 static struct filterops proc_filtops = {
165 .f_isfd = 0,
166 .f_attach = filt_procattach,
167 .f_detach = filt_procdetach,
168 .f_event = filt_proc,
169 };
170 static struct filterops timer_filtops = {
171 .f_isfd = 0,
172 .f_attach = filt_timerattach,
173 .f_detach = filt_timerdetach,
174 .f_event = filt_timer,
175 };
176 static struct filterops user_filtops = {
177 .f_attach = filt_userattach,
178 .f_detach = filt_userdetach,
179 .f_event = filt_user,
180 .f_touch = filt_usertouch,
181 };
182
183 static uma_zone_t knote_zone;
184 static int kq_ncallouts = 0;
185 static int kq_calloutmax = (4 * 1024);
186 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
187 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
188
189 /* XXX - ensure not KN_INFLUX?? */
190 #define KNOTE_ACTIVATE(kn, islock) do { \
191 if ((islock)) \
192 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \
193 else \
194 KQ_LOCK((kn)->kn_kq); \
195 (kn)->kn_status |= KN_ACTIVE; \
196 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
197 knote_enqueue((kn)); \
198 if (!(islock)) \
199 KQ_UNLOCK((kn)->kn_kq); \
200 } while(0)
201 #define KQ_LOCK(kq) do { \
202 mtx_lock(&(kq)->kq_lock); \
203 } while (0)
204 #define KQ_FLUX_WAKEUP(kq) do { \
205 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \
206 (kq)->kq_state &= ~KQ_FLUXWAIT; \
207 wakeup((kq)); \
208 } \
209 } while (0)
210 #define KQ_UNLOCK_FLUX(kq) do { \
211 KQ_FLUX_WAKEUP(kq); \
212 mtx_unlock(&(kq)->kq_lock); \
213 } while (0)
214 #define KQ_UNLOCK(kq) do { \
215 mtx_unlock(&(kq)->kq_lock); \
216 } while (0)
217 #define KQ_OWNED(kq) do { \
218 mtx_assert(&(kq)->kq_lock, MA_OWNED); \
219 } while (0)
220 #define KQ_NOTOWNED(kq) do { \
221 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \
222 } while (0)
223 #define KN_LIST_LOCK(kn) do { \
224 if (kn->kn_knlist != NULL) \
225 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \
226 } while (0)
227 #define KN_LIST_UNLOCK(kn) do { \
228 if (kn->kn_knlist != NULL) \
229 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \
230 } while (0)
231 #define KNL_ASSERT_LOCK(knl, islocked) do { \
232 if (islocked) \
233 KNL_ASSERT_LOCKED(knl); \
234 else \
235 KNL_ASSERT_UNLOCKED(knl); \
236 } while (0)
237 #ifdef INVARIANTS
238 #define KNL_ASSERT_LOCKED(knl) do { \
239 knl->kl_assert_locked((knl)->kl_lockarg); \
240 } while (0)
241 #define KNL_ASSERT_UNLOCKED(knl) do { \
242 knl->kl_assert_unlocked((knl)->kl_lockarg); \
243 } while (0)
244 #else /* !INVARIANTS */
245 #define KNL_ASSERT_LOCKED(knl) do {} while(0)
246 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
247 #endif /* INVARIANTS */
248
249 #define KN_HASHSIZE 64 /* XXX should be tunable */
250 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
251
252 static int
253 filt_nullattach(struct knote *kn)
254 {
255
256 return (ENXIO);
257 };
258
259 struct filterops null_filtops = {
260 .f_isfd = 0,
261 .f_attach = filt_nullattach,
262 };
263
264 /* XXX - make SYSINIT to add these, and move into respective modules. */
265 extern struct filterops sig_filtops;
266 extern struct filterops fs_filtops;
267
268 /*
269 * Table for for all system-defined filters.
270 */
271 static struct mtx filterops_lock;
272 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops",
273 MTX_DEF);
274 static struct {
275 struct filterops *for_fop;
276 int for_refcnt;
277 } sysfilt_ops[EVFILT_SYSCOUNT] = {
278 { &file_filtops }, /* EVFILT_READ */
279 { &file_filtops }, /* EVFILT_WRITE */
280 { &null_filtops }, /* EVFILT_AIO */
281 { &file_filtops }, /* EVFILT_VNODE */
282 { &proc_filtops }, /* EVFILT_PROC */
283 { &sig_filtops }, /* EVFILT_SIGNAL */
284 { &timer_filtops }, /* EVFILT_TIMER */
285 { &null_filtops }, /* former EVFILT_NETDEV */
286 { &fs_filtops }, /* EVFILT_FS */
287 { &null_filtops }, /* EVFILT_LIO */
288 { &user_filtops }, /* EVFILT_USER */
289 };
290
291 /*
292 * Simple redirection for all cdevsw style objects to call their fo_kqfilter
293 * method.
294 */
295 static int
296 filt_fileattach(struct knote *kn)
297 {
298
299 return (fo_kqfilter(kn->kn_fp, kn));
300 }
301
302 /*ARGSUSED*/
303 static int
304 kqueue_kqfilter(struct file *fp, struct knote *kn)
305 {
306 struct kqueue *kq = kn->kn_fp->f_data;
307
308 if (kn->kn_filter != EVFILT_READ)
309 return (EINVAL);
310
311 kn->kn_status |= KN_KQUEUE;
312 kn->kn_fop = &kqread_filtops;
313 knlist_add(&kq->kq_sel.si_note, kn, 0);
314
315 return (0);
316 }
317
318 static void
319 filt_kqdetach(struct knote *kn)
320 {
321 struct kqueue *kq = kn->kn_fp->f_data;
322
323 knlist_remove(&kq->kq_sel.si_note, kn, 0);
324 }
325
326 /*ARGSUSED*/
327 static int
328 filt_kqueue(struct knote *kn, long hint)
329 {
330 struct kqueue *kq = kn->kn_fp->f_data;
331
332 kn->kn_data = kq->kq_count;
333 return (kn->kn_data > 0);
334 }
335
336 /* XXX - move to kern_proc.c? */
337 static int
338 filt_procattach(struct knote *kn)
339 {
340 struct proc *p;
341 int immediate;
342 int error;
343
344 immediate = 0;
345 p = pfind(kn->kn_id);
346 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
347 p = zpfind(kn->kn_id);
348 immediate = 1;
349 } else if (p != NULL && (p->p_flag & P_WEXIT)) {
350 immediate = 1;
351 }
352
353 if (p == NULL)
354 return (ESRCH);
355 if ((error = p_cansee(curthread, p))) {
356 PROC_UNLOCK(p);
357 return (error);
358 }
359
360 kn->kn_ptr.p_proc = p;
361 kn->kn_flags |= EV_CLEAR; /* automatically set */
362
363 /*
364 * internal flag indicating registration done by kernel
365 */
366 if (kn->kn_flags & EV_FLAG1) {
367 kn->kn_data = kn->kn_sdata; /* ppid */
368 kn->kn_fflags = NOTE_CHILD;
369 kn->kn_flags &= ~EV_FLAG1;
370 }
371
372 if (immediate == 0)
373 knlist_add(&p->p_klist, kn, 1);
374
375 /*
376 * Immediately activate any exit notes if the target process is a
377 * zombie. This is necessary to handle the case where the target
378 * process, e.g. a child, dies before the kevent is registered.
379 */
380 if (immediate && filt_proc(kn, NOTE_EXIT))
381 KNOTE_ACTIVATE(kn, 0);
382
383 PROC_UNLOCK(p);
384
385 return (0);
386 }
387
388 /*
389 * The knote may be attached to a different process, which may exit,
390 * leaving nothing for the knote to be attached to. So when the process
391 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
392 * it will be deleted when read out. However, as part of the knote deletion,
393 * this routine is called, so a check is needed to avoid actually performing
394 * a detach, because the original process does not exist any more.
395 */
396 /* XXX - move to kern_proc.c? */
397 static void
398 filt_procdetach(struct knote *kn)
399 {
400 struct proc *p;
401
402 p = kn->kn_ptr.p_proc;
403 knlist_remove(&p->p_klist, kn, 0);
404 kn->kn_ptr.p_proc = NULL;
405 }
406
407 /* XXX - move to kern_proc.c? */
408 static int
409 filt_proc(struct knote *kn, long hint)
410 {
411 struct proc *p = kn->kn_ptr.p_proc;
412 u_int event;
413
414 /*
415 * mask off extra data
416 */
417 event = (u_int)hint & NOTE_PCTRLMASK;
418
419 /*
420 * if the user is interested in this event, record it.
421 */
422 if (kn->kn_sfflags & event)
423 kn->kn_fflags |= event;
424
425 /*
426 * process is gone, so flag the event as finished.
427 */
428 if (event == NOTE_EXIT) {
429 if (!(kn->kn_status & KN_DETACHED))
430 knlist_remove_inevent(&p->p_klist, kn);
431 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
432 kn->kn_data = p->p_xstat;
433 kn->kn_ptr.p_proc = NULL;
434 return (1);
435 }
436
437 return (kn->kn_fflags != 0);
438 }
439
440 /*
441 * Called when the process forked. It mostly does the same as the
442 * knote(), activating all knotes registered to be activated when the
443 * process forked. Additionally, for each knote attached to the
444 * parent, check whether user wants to track the new process. If so
445 * attach a new knote to it, and immediately report an event with the
446 * child's pid.
447 */
448 void
449 knote_fork(struct knlist *list, int pid)
450 {
451 struct kqueue *kq;
452 struct knote *kn;
453 struct kevent kev;
454 int error;
455
456 if (list == NULL)
457 return;
458 list->kl_lock(list->kl_lockarg);
459
460 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
461 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX)
462 continue;
463 kq = kn->kn_kq;
464 KQ_LOCK(kq);
465 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
466 KQ_UNLOCK(kq);
467 continue;
468 }
469
470 /*
471 * The same as knote(), activate the event.
472 */
473 if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
474 kn->kn_status |= KN_HASKQLOCK;
475 if (kn->kn_fop->f_event(kn, NOTE_FORK | pid))
476 KNOTE_ACTIVATE(kn, 1);
477 kn->kn_status &= ~KN_HASKQLOCK;
478 KQ_UNLOCK(kq);
479 continue;
480 }
481
482 /*
483 * The NOTE_TRACK case. In addition to the activation
484 * of the event, we need to register new event to
485 * track the child. Drop the locks in preparation for
486 * the call to kqueue_register().
487 */
488 kn->kn_status |= KN_INFLUX;
489 KQ_UNLOCK(kq);
490 list->kl_unlock(list->kl_lockarg);
491
492 /*
493 * Activate existing knote and register a knote with
494 * new process.
495 */
496 kev.ident = pid;
497 kev.filter = kn->kn_filter;
498 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
499 kev.fflags = kn->kn_sfflags;
500 kev.data = kn->kn_id; /* parent */
501 kev.udata = kn->kn_kevent.udata;/* preserve udata */
502 error = kqueue_register(kq, &kev, NULL, 0);
503 if (kn->kn_fop->f_event(kn, NOTE_FORK | pid))
504 KNOTE_ACTIVATE(kn, 0);
505 if (error)
506 kn->kn_fflags |= NOTE_TRACKERR;
507 KQ_LOCK(kq);
508 kn->kn_status &= ~KN_INFLUX;
509 KQ_UNLOCK_FLUX(kq);
510 list->kl_lock(list->kl_lockarg);
511 }
512 list->kl_unlock(list->kl_lockarg);
513 }
514
515 static int
516 timertoticks(intptr_t data)
517 {
518 struct timeval tv;
519 int tticks;
520
521 tv.tv_sec = data / 1000;
522 tv.tv_usec = (data % 1000) * 1000;
523 tticks = tvtohz(&tv);
524
525 return tticks;
526 }
527
528 /* XXX - move to kern_timeout.c? */
529 static void
530 filt_timerexpire(void *knx)
531 {
532 struct knote *kn = knx;
533 struct callout *calloutp;
534
535 kn->kn_data++;
536 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
537
538 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) {
539 calloutp = (struct callout *)kn->kn_hook;
540 callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata),
541 filt_timerexpire, kn);
542 }
543 }
544
545 /*
546 * data contains amount of time to sleep, in milliseconds
547 */
548 /* XXX - move to kern_timeout.c? */
549 static int
550 filt_timerattach(struct knote *kn)
551 {
552 struct callout *calloutp;
553
554 atomic_add_int(&kq_ncallouts, 1);
555
556 if (kq_ncallouts >= kq_calloutmax) {
557 atomic_add_int(&kq_ncallouts, -1);
558 return (ENOMEM);
559 }
560
561 kn->kn_flags |= EV_CLEAR; /* automatically set */
562 kn->kn_status &= ~KN_DETACHED; /* knlist_add usually sets it */
563 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK);
564 callout_init(calloutp, CALLOUT_MPSAFE);
565 kn->kn_hook = calloutp;
566 callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata),
567 filt_timerexpire, kn);
568
569 return (0);
570 }
571
572 /* XXX - move to kern_timeout.c? */
573 static void
574 filt_timerdetach(struct knote *kn)
575 {
576 struct callout *calloutp;
577
578 calloutp = (struct callout *)kn->kn_hook;
579 callout_drain(calloutp);
580 free(calloutp, M_KQUEUE);
581 atomic_add_int(&kq_ncallouts, -1);
582 kn->kn_status |= KN_DETACHED; /* knlist_remove usually clears it */
583 }
584
585 /* XXX - move to kern_timeout.c? */
586 static int
587 filt_timer(struct knote *kn, long hint)
588 {
589
590 return (kn->kn_data != 0);
591 }
592
593 static int
594 filt_userattach(struct knote *kn)
595 {
596
597 /*
598 * EVFILT_USER knotes are not attached to anything in the kernel.
599 */
600 kn->kn_hook = NULL;
601 if (kn->kn_fflags & NOTE_TRIGGER)
602 kn->kn_hookid = 1;
603 else
604 kn->kn_hookid = 0;
605 return (0);
606 }
607
608 static void
609 filt_userdetach(__unused struct knote *kn)
610 {
611
612 /*
613 * EVFILT_USER knotes are not attached to anything in the kernel.
614 */
615 }
616
617 static int
618 filt_user(struct knote *kn, __unused long hint)
619 {
620
621 return (kn->kn_hookid);
622 }
623
624 static void
625 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
626 {
627 u_int ffctrl;
628
629 switch (type) {
630 case EVENT_REGISTER:
631 if (kev->fflags & NOTE_TRIGGER)
632 kn->kn_hookid = 1;
633
634 ffctrl = kev->fflags & NOTE_FFCTRLMASK;
635 kev->fflags &= NOTE_FFLAGSMASK;
636 switch (ffctrl) {
637 case NOTE_FFNOP:
638 break;
639
640 case NOTE_FFAND:
641 kn->kn_sfflags &= kev->fflags;
642 break;
643
644 case NOTE_FFOR:
645 kn->kn_sfflags |= kev->fflags;
646 break;
647
648 case NOTE_FFCOPY:
649 kn->kn_sfflags = kev->fflags;
650 break;
651
652 default:
653 /* XXX Return error? */
654 break;
655 }
656 kn->kn_sdata = kev->data;
657 if (kev->flags & EV_CLEAR) {
658 kn->kn_hookid = 0;
659 kn->kn_data = 0;
660 kn->kn_fflags = 0;
661 }
662 break;
663
664 case EVENT_PROCESS:
665 *kev = kn->kn_kevent;
666 kev->fflags = kn->kn_sfflags;
667 kev->data = kn->kn_sdata;
668 if (kn->kn_flags & EV_CLEAR) {
669 kn->kn_hookid = 0;
670 kn->kn_data = 0;
671 kn->kn_fflags = 0;
672 }
673 break;
674
675 default:
676 panic("filt_usertouch() - invalid type (%ld)", type);
677 break;
678 }
679 }
680
681 int
682 sys_kqueue(struct thread *td, struct kqueue_args *uap)
683 {
684 struct filedesc *fdp;
685 struct kqueue *kq;
686 struct file *fp;
687 int fd, error;
688
689 fdp = td->td_proc->p_fd;
690 error = falloc(td, &fp, &fd, 0);
691 if (error)
692 goto done2;
693
694 /* An extra reference on `nfp' has been held for us by falloc(). */
695 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
696 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK);
697 TAILQ_INIT(&kq->kq_head);
698 kq->kq_fdp = fdp;
699 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
700 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
701
702 FILEDESC_XLOCK(fdp);
703 SLIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
704 FILEDESC_XUNLOCK(fdp);
705
706 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
707 fdrop(fp, td);
708
709 td->td_retval[0] = fd;
710 done2:
711 return (error);
712 }
713
714 #ifndef _SYS_SYSPROTO_H_
715 struct kevent_args {
716 int fd;
717 const struct kevent *changelist;
718 int nchanges;
719 struct kevent *eventlist;
720 int nevents;
721 const struct timespec *timeout;
722 };
723 #endif
724 int
725 sys_kevent(struct thread *td, struct kevent_args *uap)
726 {
727 struct timespec ts, *tsp;
728 struct kevent_copyops k_ops = { uap,
729 kevent_copyout,
730 kevent_copyin};
731 int error;
732 #ifdef KTRACE
733 struct uio ktruio;
734 struct iovec ktriov;
735 struct uio *ktruioin = NULL;
736 struct uio *ktruioout = NULL;
737 #endif
738
739 if (uap->timeout != NULL) {
740 error = copyin(uap->timeout, &ts, sizeof(ts));
741 if (error)
742 return (error);
743 tsp = &ts;
744 } else
745 tsp = NULL;
746
747 #ifdef KTRACE
748 if (KTRPOINT(td, KTR_GENIO)) {
749 ktriov.iov_base = uap->changelist;
750 ktriov.iov_len = uap->nchanges * sizeof(struct kevent);
751 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1,
752 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ,
753 .uio_td = td };
754 ktruioin = cloneuio(&ktruio);
755 ktriov.iov_base = uap->eventlist;
756 ktriov.iov_len = uap->nevents * sizeof(struct kevent);
757 ktruioout = cloneuio(&ktruio);
758 }
759 #endif
760
761 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
762 &k_ops, tsp);
763
764 #ifdef KTRACE
765 if (ktruioin != NULL) {
766 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent);
767 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0);
768 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent);
769 ktrgenio(uap->fd, UIO_READ, ktruioout, error);
770 }
771 #endif
772
773 return (error);
774 }
775
776 /*
777 * Copy 'count' items into the destination list pointed to by uap->eventlist.
778 */
779 static int
780 kevent_copyout(void *arg, struct kevent *kevp, int count)
781 {
782 struct kevent_args *uap;
783 int error;
784
785 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
786 uap = (struct kevent_args *)arg;
787
788 error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
789 if (error == 0)
790 uap->eventlist += count;
791 return (error);
792 }
793
794 /*
795 * Copy 'count' items from the list pointed to by uap->changelist.
796 */
797 static int
798 kevent_copyin(void *arg, struct kevent *kevp, int count)
799 {
800 struct kevent_args *uap;
801 int error;
802
803 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
804 uap = (struct kevent_args *)arg;
805
806 error = copyin(uap->changelist, kevp, count * sizeof *kevp);
807 if (error == 0)
808 uap->changelist += count;
809 return (error);
810 }
811
812 int
813 kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
814 struct kevent_copyops *k_ops, const struct timespec *timeout)
815 {
816 struct kevent keva[KQ_NEVENTS];
817 struct kevent *kevp, *changes;
818 struct kqueue *kq;
819 struct file *fp;
820 int i, n, nerrors, error;
821
822 if ((error = fget(td, fd, CAP_POST_EVENT, &fp)) != 0)
823 return (error);
824 if ((error = kqueue_acquire(fp, &kq)) != 0)
825 goto done_norel;
826
827 nerrors = 0;
828
829 while (nchanges > 0) {
830 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
831 error = k_ops->k_copyin(k_ops->arg, keva, n);
832 if (error)
833 goto done;
834 changes = keva;
835 for (i = 0; i < n; i++) {
836 kevp = &changes[i];
837 if (!kevp->filter)
838 continue;
839 kevp->flags &= ~EV_SYSFLAGS;
840 error = kqueue_register(kq, kevp, td, 1);
841 if (error || (kevp->flags & EV_RECEIPT)) {
842 if (nevents != 0) {
843 kevp->flags = EV_ERROR;
844 kevp->data = error;
845 (void) k_ops->k_copyout(k_ops->arg,
846 kevp, 1);
847 nevents--;
848 nerrors++;
849 } else {
850 goto done;
851 }
852 }
853 }
854 nchanges -= n;
855 }
856 if (nerrors) {
857 td->td_retval[0] = nerrors;
858 error = 0;
859 goto done;
860 }
861
862 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td);
863 done:
864 kqueue_release(kq, 0);
865 done_norel:
866 fdrop(fp, td);
867 return (error);
868 }
869
870 int
871 kqueue_add_filteropts(int filt, struct filterops *filtops)
872 {
873 int error;
874
875 error = 0;
876 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
877 printf(
878 "trying to add a filterop that is out of range: %d is beyond %d\n",
879 ~filt, EVFILT_SYSCOUNT);
880 return EINVAL;
881 }
882 mtx_lock(&filterops_lock);
883 if (sysfilt_ops[~filt].for_fop != &null_filtops &&
884 sysfilt_ops[~filt].for_fop != NULL)
885 error = EEXIST;
886 else {
887 sysfilt_ops[~filt].for_fop = filtops;
888 sysfilt_ops[~filt].for_refcnt = 0;
889 }
890 mtx_unlock(&filterops_lock);
891
892 return (error);
893 }
894
895 int
896 kqueue_del_filteropts(int filt)
897 {
898 int error;
899
900 error = 0;
901 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
902 return EINVAL;
903
904 mtx_lock(&filterops_lock);
905 if (sysfilt_ops[~filt].for_fop == &null_filtops ||
906 sysfilt_ops[~filt].for_fop == NULL)
907 error = EINVAL;
908 else if (sysfilt_ops[~filt].for_refcnt != 0)
909 error = EBUSY;
910 else {
911 sysfilt_ops[~filt].for_fop = &null_filtops;
912 sysfilt_ops[~filt].for_refcnt = 0;
913 }
914 mtx_unlock(&filterops_lock);
915
916 return error;
917 }
918
919 static struct filterops *
920 kqueue_fo_find(int filt)
921 {
922
923 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
924 return NULL;
925
926 mtx_lock(&filterops_lock);
927 sysfilt_ops[~filt].for_refcnt++;
928 if (sysfilt_ops[~filt].for_fop == NULL)
929 sysfilt_ops[~filt].for_fop = &null_filtops;
930 mtx_unlock(&filterops_lock);
931
932 return sysfilt_ops[~filt].for_fop;
933 }
934
935 static void
936 kqueue_fo_release(int filt)
937 {
938
939 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
940 return;
941
942 mtx_lock(&filterops_lock);
943 KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
944 ("filter object refcount not valid on release"));
945 sysfilt_ops[~filt].for_refcnt--;
946 mtx_unlock(&filterops_lock);
947 }
948
949 /*
950 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will
951 * influence if memory allocation should wait. Make sure it is 0 if you
952 * hold any mutexes.
953 */
954 static int
955 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok)
956 {
957 struct filterops *fops;
958 struct file *fp;
959 struct knote *kn, *tkn;
960 int error, filt, event;
961 int haskqglobal;
962
963 fp = NULL;
964 kn = NULL;
965 error = 0;
966 haskqglobal = 0;
967
968 filt = kev->filter;
969 fops = kqueue_fo_find(filt);
970 if (fops == NULL)
971 return EINVAL;
972
973 tkn = knote_alloc(waitok); /* prevent waiting with locks */
974
975 findkn:
976 if (fops->f_isfd) {
977 KASSERT(td != NULL, ("td is NULL"));
978 error = fget(td, kev->ident, CAP_POLL_EVENT, &fp);
979 if (error)
980 goto done;
981
982 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
983 kev->ident, 0) != 0) {
984 /* try again */
985 fdrop(fp, td);
986 fp = NULL;
987 error = kqueue_expand(kq, fops, kev->ident, waitok);
988 if (error)
989 goto done;
990 goto findkn;
991 }
992
993 if (fp->f_type == DTYPE_KQUEUE) {
994 /*
995 * if we add some inteligence about what we are doing,
996 * we should be able to support events on ourselves.
997 * We need to know when we are doing this to prevent
998 * getting both the knlist lock and the kq lock since
999 * they are the same thing.
1000 */
1001 if (fp->f_data == kq) {
1002 error = EINVAL;
1003 goto done;
1004 }
1005
1006 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1007 }
1008
1009 KQ_LOCK(kq);
1010 if (kev->ident < kq->kq_knlistsize) {
1011 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
1012 if (kev->filter == kn->kn_filter)
1013 break;
1014 }
1015 } else {
1016 if ((kev->flags & EV_ADD) == EV_ADD)
1017 kqueue_expand(kq, fops, kev->ident, waitok);
1018
1019 KQ_LOCK(kq);
1020 if (kq->kq_knhashmask != 0) {
1021 struct klist *list;
1022
1023 list = &kq->kq_knhash[
1024 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
1025 SLIST_FOREACH(kn, list, kn_link)
1026 if (kev->ident == kn->kn_id &&
1027 kev->filter == kn->kn_filter)
1028 break;
1029 }
1030 }
1031
1032 /* knote is in the process of changing, wait for it to stablize. */
1033 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1034 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1035 kq->kq_state |= KQ_FLUXWAIT;
1036 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
1037 if (fp != NULL) {
1038 fdrop(fp, td);
1039 fp = NULL;
1040 }
1041 goto findkn;
1042 }
1043
1044 /*
1045 * kn now contains the matching knote, or NULL if no match
1046 */
1047 if (kn == NULL) {
1048 if (kev->flags & EV_ADD) {
1049 kn = tkn;
1050 tkn = NULL;
1051 if (kn == NULL) {
1052 KQ_UNLOCK(kq);
1053 error = ENOMEM;
1054 goto done;
1055 }
1056 kn->kn_fp = fp;
1057 kn->kn_kq = kq;
1058 kn->kn_fop = fops;
1059 /*
1060 * apply reference counts to knote structure, and
1061 * do not release it at the end of this routine.
1062 */
1063 fops = NULL;
1064 fp = NULL;
1065
1066 kn->kn_sfflags = kev->fflags;
1067 kn->kn_sdata = kev->data;
1068 kev->fflags = 0;
1069 kev->data = 0;
1070 kn->kn_kevent = *kev;
1071 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
1072 EV_ENABLE | EV_DISABLE);
1073 kn->kn_status = KN_INFLUX|KN_DETACHED;
1074
1075 error = knote_attach(kn, kq);
1076 KQ_UNLOCK(kq);
1077 if (error != 0) {
1078 tkn = kn;
1079 goto done;
1080 }
1081
1082 if ((error = kn->kn_fop->f_attach(kn)) != 0) {
1083 knote_drop(kn, td);
1084 goto done;
1085 }
1086 KN_LIST_LOCK(kn);
1087 goto done_ev_add;
1088 } else {
1089 /* No matching knote and the EV_ADD flag is not set. */
1090 KQ_UNLOCK(kq);
1091 error = ENOENT;
1092 goto done;
1093 }
1094 }
1095
1096 if (kev->flags & EV_DELETE) {
1097 kn->kn_status |= KN_INFLUX;
1098 KQ_UNLOCK(kq);
1099 if (!(kn->kn_status & KN_DETACHED))
1100 kn->kn_fop->f_detach(kn);
1101 knote_drop(kn, td);
1102 goto done;
1103 }
1104
1105 /*
1106 * The user may change some filter values after the initial EV_ADD,
1107 * but doing so will not reset any filter which has already been
1108 * triggered.
1109 */
1110 kn->kn_status |= KN_INFLUX;
1111 KQ_UNLOCK(kq);
1112 KN_LIST_LOCK(kn);
1113 kn->kn_kevent.udata = kev->udata;
1114 if (!fops->f_isfd && fops->f_touch != NULL) {
1115 fops->f_touch(kn, kev, EVENT_REGISTER);
1116 } else {
1117 kn->kn_sfflags = kev->fflags;
1118 kn->kn_sdata = kev->data;
1119 }
1120
1121 /*
1122 * We can get here with kn->kn_knlist == NULL. This can happen when
1123 * the initial attach event decides that the event is "completed"
1124 * already. i.e. filt_procattach is called on a zombie process. It
1125 * will call filt_proc which will remove it from the list, and NULL
1126 * kn_knlist.
1127 */
1128 done_ev_add:
1129 event = kn->kn_fop->f_event(kn, 0);
1130 KQ_LOCK(kq);
1131 if (event)
1132 KNOTE_ACTIVATE(kn, 1);
1133 kn->kn_status &= ~KN_INFLUX;
1134 KN_LIST_UNLOCK(kn);
1135
1136 if ((kev->flags & EV_DISABLE) &&
1137 ((kn->kn_status & KN_DISABLED) == 0)) {
1138 kn->kn_status |= KN_DISABLED;
1139 }
1140
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))
1145 knote_enqueue(kn);
1146 }
1147 KQ_UNLOCK_FLUX(kq);
1148
1149 done:
1150 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1151 if (fp != NULL)
1152 fdrop(fp, td);
1153 if (tkn != NULL)
1154 knote_free(tkn);
1155 if (fops != NULL)
1156 kqueue_fo_release(filt);
1157 return (error);
1158 }
1159
1160 static int
1161 kqueue_acquire(struct file *fp, struct kqueue **kqp)
1162 {
1163 int error;
1164 struct kqueue *kq;
1165
1166 error = 0;
1167
1168 kq = fp->f_data;
1169 if (fp->f_type != DTYPE_KQUEUE || kq == NULL)
1170 return (EBADF);
1171 *kqp = kq;
1172 KQ_LOCK(kq);
1173 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
1174 KQ_UNLOCK(kq);
1175 return (EBADF);
1176 }
1177 kq->kq_refcnt++;
1178 KQ_UNLOCK(kq);
1179
1180 return error;
1181 }
1182
1183 static void
1184 kqueue_release(struct kqueue *kq, int locked)
1185 {
1186 if (locked)
1187 KQ_OWNED(kq);
1188 else
1189 KQ_LOCK(kq);
1190 kq->kq_refcnt--;
1191 if (kq->kq_refcnt == 1)
1192 wakeup(&kq->kq_refcnt);
1193 if (!locked)
1194 KQ_UNLOCK(kq);
1195 }
1196
1197 static void
1198 kqueue_schedtask(struct kqueue *kq)
1199 {
1200
1201 KQ_OWNED(kq);
1202 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
1203 ("scheduling kqueue task while draining"));
1204
1205 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
1206 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task);
1207 kq->kq_state |= KQ_TASKSCHED;
1208 }
1209 }
1210
1211 /*
1212 * Expand the kq to make sure we have storage for fops/ident pair.
1213 *
1214 * Return 0 on success (or no work necessary), return errno on failure.
1215 *
1216 * Not calling hashinit w/ waitok (proper malloc flag) should be safe.
1217 * If kqueue_register is called from a non-fd context, there usually/should
1218 * be no locks held.
1219 */
1220 static int
1221 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident,
1222 int waitok)
1223 {
1224 struct klist *list, *tmp_knhash, *to_free;
1225 u_long tmp_knhashmask;
1226 int size;
1227 int fd;
1228 int mflag = waitok ? M_WAITOK : M_NOWAIT;
1229
1230 KQ_NOTOWNED(kq);
1231
1232 to_free = NULL;
1233 if (fops->f_isfd) {
1234 fd = ident;
1235 if (kq->kq_knlistsize <= fd) {
1236 size = kq->kq_knlistsize;
1237 while (size <= fd)
1238 size += KQEXTENT;
1239 list = malloc(size * sizeof(*list), M_KQUEUE, mflag);
1240 if (list == NULL)
1241 return ENOMEM;
1242 KQ_LOCK(kq);
1243 if (kq->kq_knlistsize > fd) {
1244 to_free = list;
1245 list = NULL;
1246 } else {
1247 if (kq->kq_knlist != NULL) {
1248 bcopy(kq->kq_knlist, list,
1249 kq->kq_knlistsize * sizeof(*list));
1250 to_free = kq->kq_knlist;
1251 kq->kq_knlist = NULL;
1252 }
1253 bzero((caddr_t)list +
1254 kq->kq_knlistsize * sizeof(*list),
1255 (size - kq->kq_knlistsize) * sizeof(*list));
1256 kq->kq_knlistsize = size;
1257 kq->kq_knlist = list;
1258 }
1259 KQ_UNLOCK(kq);
1260 }
1261 } else {
1262 if (kq->kq_knhashmask == 0) {
1263 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
1264 &tmp_knhashmask);
1265 if (tmp_knhash == NULL)
1266 return ENOMEM;
1267 KQ_LOCK(kq);
1268 if (kq->kq_knhashmask == 0) {
1269 kq->kq_knhash = tmp_knhash;
1270 kq->kq_knhashmask = tmp_knhashmask;
1271 } else {
1272 to_free = tmp_knhash;
1273 }
1274 KQ_UNLOCK(kq);
1275 }
1276 }
1277 free(to_free, M_KQUEUE);
1278
1279 KQ_NOTOWNED(kq);
1280 return 0;
1281 }
1282
1283 static void
1284 kqueue_task(void *arg, int pending)
1285 {
1286 struct kqueue *kq;
1287 int haskqglobal;
1288
1289 haskqglobal = 0;
1290 kq = arg;
1291
1292 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1293 KQ_LOCK(kq);
1294
1295 KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
1296
1297 kq->kq_state &= ~KQ_TASKSCHED;
1298 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
1299 wakeup(&kq->kq_state);
1300 }
1301 KQ_UNLOCK(kq);
1302 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1303 }
1304
1305 /*
1306 * Scan, update kn_data (if not ONESHOT), and copyout triggered events.
1307 * We treat KN_MARKER knotes as if they are INFLUX.
1308 */
1309 static int
1310 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
1311 const struct timespec *tsp, struct kevent *keva, struct thread *td)
1312 {
1313 struct kevent *kevp;
1314 struct timeval atv, rtv, ttv;
1315 struct knote *kn, *marker;
1316 int count, timeout, nkev, error, influx;
1317 int haskqglobal, touch;
1318
1319 count = maxevents;
1320 nkev = 0;
1321 error = 0;
1322 haskqglobal = 0;
1323
1324 if (maxevents == 0)
1325 goto done_nl;
1326
1327 if (tsp != NULL) {
1328 TIMESPEC_TO_TIMEVAL(&atv, tsp);
1329 if (itimerfix(&atv)) {
1330 error = EINVAL;
1331 goto done_nl;
1332 }
1333 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
1334 timeout = -1;
1335 else
1336 timeout = atv.tv_sec > 24 * 60 * 60 ?
1337 24 * 60 * 60 * hz : tvtohz(&atv);
1338 getmicrouptime(&rtv);
1339 timevaladd(&atv, &rtv);
1340 } else {
1341 atv.tv_sec = 0;
1342 atv.tv_usec = 0;
1343 timeout = 0;
1344 }
1345 marker = knote_alloc(1);
1346 if (marker == NULL) {
1347 error = ENOMEM;
1348 goto done_nl;
1349 }
1350 marker->kn_status = KN_MARKER;
1351 KQ_LOCK(kq);
1352 goto start;
1353
1354 retry:
1355 if (atv.tv_sec || atv.tv_usec) {
1356 getmicrouptime(&rtv);
1357 if (timevalcmp(&rtv, &atv, >=))
1358 goto done;
1359 ttv = atv;
1360 timevalsub(&ttv, &rtv);
1361 timeout = ttv.tv_sec > 24 * 60 * 60 ?
1362 24 * 60 * 60 * hz : tvtohz(&ttv);
1363 }
1364
1365 start:
1366 kevp = keva;
1367 if (kq->kq_count == 0) {
1368 if (timeout < 0) {
1369 error = EWOULDBLOCK;
1370 } else {
1371 kq->kq_state |= KQ_SLEEP;
1372 error = msleep(kq, &kq->kq_lock, PSOCK | PCATCH,
1373 "kqread", timeout);
1374 }
1375 if (error == 0)
1376 goto retry;
1377 /* don't restart after signals... */
1378 if (error == ERESTART)
1379 error = EINTR;
1380 else if (error == EWOULDBLOCK)
1381 error = 0;
1382 goto done;
1383 }
1384
1385 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
1386 influx = 0;
1387 while (count) {
1388 KQ_OWNED(kq);
1389 kn = TAILQ_FIRST(&kq->kq_head);
1390
1391 if ((kn->kn_status == KN_MARKER && kn != marker) ||
1392 (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1393 if (influx) {
1394 influx = 0;
1395 KQ_FLUX_WAKEUP(kq);
1396 }
1397 kq->kq_state |= KQ_FLUXWAIT;
1398 error = msleep(kq, &kq->kq_lock, PSOCK,
1399 "kqflxwt", 0);
1400 continue;
1401 }
1402
1403 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
1404 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
1405 kn->kn_status &= ~KN_QUEUED;
1406 kq->kq_count--;
1407 continue;
1408 }
1409 if (kn == marker) {
1410 KQ_FLUX_WAKEUP(kq);
1411 if (count == maxevents)
1412 goto retry;
1413 goto done;
1414 }
1415 KASSERT((kn->kn_status & KN_INFLUX) == 0,
1416 ("KN_INFLUX set when not suppose to be"));
1417
1418 if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
1419 kn->kn_status &= ~KN_QUEUED;
1420 kn->kn_status |= KN_INFLUX;
1421 kq->kq_count--;
1422 KQ_UNLOCK(kq);
1423 /*
1424 * We don't need to lock the list since we've marked
1425 * it _INFLUX.
1426 */
1427 *kevp = kn->kn_kevent;
1428 if (!(kn->kn_status & KN_DETACHED))
1429 kn->kn_fop->f_detach(kn);
1430 knote_drop(kn, td);
1431 KQ_LOCK(kq);
1432 kn = NULL;
1433 } else {
1434 kn->kn_status |= KN_INFLUX;
1435 KQ_UNLOCK(kq);
1436 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
1437 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1438 KN_LIST_LOCK(kn);
1439 if (kn->kn_fop->f_event(kn, 0) == 0) {
1440 KQ_LOCK(kq);
1441 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1442 kn->kn_status &=
1443 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX);
1444 kq->kq_count--;
1445 KN_LIST_UNLOCK(kn);
1446 influx = 1;
1447 continue;
1448 }
1449 touch = (!kn->kn_fop->f_isfd &&
1450 kn->kn_fop->f_touch != NULL);
1451 if (touch)
1452 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS);
1453 else
1454 *kevp = kn->kn_kevent;
1455 KQ_LOCK(kq);
1456 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1457 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
1458 /*
1459 * Manually clear knotes who weren't
1460 * 'touch'ed.
1461 */
1462 if (touch == 0 && kn->kn_flags & EV_CLEAR) {
1463 kn->kn_data = 0;
1464 kn->kn_fflags = 0;
1465 }
1466 if (kn->kn_flags & EV_DISPATCH)
1467 kn->kn_status |= KN_DISABLED;
1468 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
1469 kq->kq_count--;
1470 } else
1471 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
1472
1473 kn->kn_status &= ~(KN_INFLUX);
1474 KN_LIST_UNLOCK(kn);
1475 influx = 1;
1476 }
1477
1478 /* we are returning a copy to the user */
1479 kevp++;
1480 nkev++;
1481 count--;
1482
1483 if (nkev == KQ_NEVENTS) {
1484 influx = 0;
1485 KQ_UNLOCK_FLUX(kq);
1486 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1487 nkev = 0;
1488 kevp = keva;
1489 KQ_LOCK(kq);
1490 if (error)
1491 break;
1492 }
1493 }
1494 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
1495 done:
1496 KQ_OWNED(kq);
1497 KQ_UNLOCK_FLUX(kq);
1498 knote_free(marker);
1499 done_nl:
1500 KQ_NOTOWNED(kq);
1501 if (nkev != 0)
1502 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1503 td->td_retval[0] = maxevents - count;
1504 return (error);
1505 }
1506
1507 /*
1508 * XXX
1509 * This could be expanded to call kqueue_scan, if desired.
1510 */
1511 /*ARGSUSED*/
1512 static int
1513 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
1514 int flags, struct thread *td)
1515 {
1516 return (ENXIO);
1517 }
1518
1519 /*ARGSUSED*/
1520 static int
1521 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
1522 int flags, struct thread *td)
1523 {
1524 return (ENXIO);
1525 }
1526
1527 /*ARGSUSED*/
1528 static int
1529 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred,
1530 struct thread *td)
1531 {
1532
1533 return (EINVAL);
1534 }
1535
1536 /*ARGSUSED*/
1537 static int
1538 kqueue_ioctl(struct file *fp, u_long cmd, void *data,
1539 struct ucred *active_cred, struct thread *td)
1540 {
1541 /*
1542 * Enabling sigio causes two major problems:
1543 * 1) infinite recursion:
1544 * Synopsys: kevent is being used to track signals and have FIOASYNC
1545 * set. On receipt of a signal this will cause a kqueue to recurse
1546 * into itself over and over. Sending the sigio causes the kqueue
1547 * to become ready, which in turn posts sigio again, forever.
1548 * Solution: this can be solved by setting a flag in the kqueue that
1549 * we have a SIGIO in progress.
1550 * 2) locking problems:
1551 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
1552 * us above the proc and pgrp locks.
1553 * Solution: Post a signal using an async mechanism, being sure to
1554 * record a generation count in the delivery so that we do not deliver
1555 * a signal to the wrong process.
1556 *
1557 * Note, these two mechanisms are somewhat mutually exclusive!
1558 */
1559 #if 0
1560 struct kqueue *kq;
1561
1562 kq = fp->f_data;
1563 switch (cmd) {
1564 case FIOASYNC:
1565 if (*(int *)data) {
1566 kq->kq_state |= KQ_ASYNC;
1567 } else {
1568 kq->kq_state &= ~KQ_ASYNC;
1569 }
1570 return (0);
1571
1572 case FIOSETOWN:
1573 return (fsetown(*(int *)data, &kq->kq_sigio));
1574
1575 case FIOGETOWN:
1576 *(int *)data = fgetown(&kq->kq_sigio);
1577 return (0);
1578 }
1579 #endif
1580
1581 return (ENOTTY);
1582 }
1583
1584 /*ARGSUSED*/
1585 static int
1586 kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
1587 struct thread *td)
1588 {
1589 struct kqueue *kq;
1590 int revents = 0;
1591 int error;
1592
1593 if ((error = kqueue_acquire(fp, &kq)))
1594 return POLLERR;
1595
1596 KQ_LOCK(kq);
1597 if (events & (POLLIN | POLLRDNORM)) {
1598 if (kq->kq_count) {
1599 revents |= events & (POLLIN | POLLRDNORM);
1600 } else {
1601 selrecord(td, &kq->kq_sel);
1602 if (SEL_WAITING(&kq->kq_sel))
1603 kq->kq_state |= KQ_SEL;
1604 }
1605 }
1606 kqueue_release(kq, 1);
1607 KQ_UNLOCK(kq);
1608 return (revents);
1609 }
1610
1611 /*ARGSUSED*/
1612 static int
1613 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
1614 struct thread *td)
1615 {
1616
1617 bzero((void *)st, sizeof *st);
1618 /*
1619 * We no longer return kq_count because the unlocked value is useless.
1620 * If you spent all this time getting the count, why not spend your
1621 * syscall better by calling kevent?
1622 *
1623 * XXX - This is needed for libc_r.
1624 */
1625 st->st_mode = S_IFIFO;
1626 return (0);
1627 }
1628
1629 /*ARGSUSED*/
1630 static int
1631 kqueue_close(struct file *fp, struct thread *td)
1632 {
1633 struct kqueue *kq = fp->f_data;
1634 struct filedesc *fdp;
1635 struct knote *kn;
1636 int i;
1637 int error;
1638
1639 if ((error = kqueue_acquire(fp, &kq)))
1640 return error;
1641
1642 KQ_LOCK(kq);
1643
1644 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
1645 ("kqueue already closing"));
1646 kq->kq_state |= KQ_CLOSING;
1647 if (kq->kq_refcnt > 1)
1648 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
1649
1650 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
1651 fdp = kq->kq_fdp;
1652
1653 KASSERT(knlist_empty(&kq->kq_sel.si_note),
1654 ("kqueue's knlist not empty"));
1655
1656 for (i = 0; i < kq->kq_knlistsize; i++) {
1657 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
1658 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1659 kq->kq_state |= KQ_FLUXWAIT;
1660 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
1661 continue;
1662 }
1663 kn->kn_status |= KN_INFLUX;
1664 KQ_UNLOCK(kq);
1665 if (!(kn->kn_status & KN_DETACHED))
1666 kn->kn_fop->f_detach(kn);
1667 knote_drop(kn, td);
1668 KQ_LOCK(kq);
1669 }
1670 }
1671 if (kq->kq_knhashmask != 0) {
1672 for (i = 0; i <= kq->kq_knhashmask; i++) {
1673 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
1674 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1675 kq->kq_state |= KQ_FLUXWAIT;
1676 msleep(kq, &kq->kq_lock, PSOCK,
1677 "kqclo2", 0);
1678 continue;
1679 }
1680 kn->kn_status |= KN_INFLUX;
1681 KQ_UNLOCK(kq);
1682 if (!(kn->kn_status & KN_DETACHED))
1683 kn->kn_fop->f_detach(kn);
1684 knote_drop(kn, td);
1685 KQ_LOCK(kq);
1686 }
1687 }
1688 }
1689
1690 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
1691 kq->kq_state |= KQ_TASKDRAIN;
1692 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
1693 }
1694
1695 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
1696 selwakeuppri(&kq->kq_sel, PSOCK);
1697 if (!SEL_WAITING(&kq->kq_sel))
1698 kq->kq_state &= ~KQ_SEL;
1699 }
1700
1701 KQ_UNLOCK(kq);
1702
1703 FILEDESC_XLOCK(fdp);
1704 SLIST_REMOVE(&fdp->fd_kqlist, kq, kqueue, kq_list);
1705 FILEDESC_XUNLOCK(fdp);
1706
1707 seldrain(&kq->kq_sel);
1708 knlist_destroy(&kq->kq_sel.si_note);
1709 mtx_destroy(&kq->kq_lock);
1710 kq->kq_fdp = NULL;
1711
1712 if (kq->kq_knhash != NULL)
1713 free(kq->kq_knhash, M_KQUEUE);
1714 if (kq->kq_knlist != NULL)
1715 free(kq->kq_knlist, M_KQUEUE);
1716
1717 funsetown(&kq->kq_sigio);
1718 free(kq, M_KQUEUE);
1719 fp->f_data = NULL;
1720
1721 return (0);
1722 }
1723
1724 static void
1725 kqueue_wakeup(struct kqueue *kq)
1726 {
1727 KQ_OWNED(kq);
1728
1729 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
1730 kq->kq_state &= ~KQ_SLEEP;
1731 wakeup(kq);
1732 }
1733 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
1734 selwakeuppri(&kq->kq_sel, PSOCK);
1735 if (!SEL_WAITING(&kq->kq_sel))
1736 kq->kq_state &= ~KQ_SEL;
1737 }
1738 if (!knlist_empty(&kq->kq_sel.si_note))
1739 kqueue_schedtask(kq);
1740 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
1741 pgsigio(&kq->kq_sigio, SIGIO, 0);
1742 }
1743 }
1744
1745 /*
1746 * Walk down a list of knotes, activating them if their event has triggered.
1747 *
1748 * There is a possibility to optimize in the case of one kq watching another.
1749 * Instead of scheduling a task to wake it up, you could pass enough state
1750 * down the chain to make up the parent kqueue. Make this code functional
1751 * first.
1752 */
1753 void
1754 knote(struct knlist *list, long hint, int lockflags)
1755 {
1756 struct kqueue *kq;
1757 struct knote *kn;
1758 int error;
1759
1760 if (list == NULL)
1761 return;
1762
1763 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
1764
1765 if ((lockflags & KNF_LISTLOCKED) == 0)
1766 list->kl_lock(list->kl_lockarg);
1767
1768 /*
1769 * If we unlock the list lock (and set KN_INFLUX), we can eliminate
1770 * the kqueue scheduling, but this will introduce four
1771 * lock/unlock's for each knote to test. If we do, continue to use
1772 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is
1773 * only safe if you want to remove the current item, which we are
1774 * not doing.
1775 */
1776 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
1777 kq = kn->kn_kq;
1778 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) {
1779 KQ_LOCK(kq);
1780 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1781 KQ_UNLOCK(kq);
1782 } else if ((lockflags & KNF_NOKQLOCK) != 0) {
1783 kn->kn_status |= KN_INFLUX;
1784 KQ_UNLOCK(kq);
1785 error = kn->kn_fop->f_event(kn, hint);
1786 KQ_LOCK(kq);
1787 kn->kn_status &= ~KN_INFLUX;
1788 if (error)
1789 KNOTE_ACTIVATE(kn, 1);
1790 KQ_UNLOCK_FLUX(kq);
1791 } else {
1792 kn->kn_status |= KN_HASKQLOCK;
1793 if (kn->kn_fop->f_event(kn, hint))
1794 KNOTE_ACTIVATE(kn, 1);
1795 kn->kn_status &= ~KN_HASKQLOCK;
1796 KQ_UNLOCK(kq);
1797 }
1798 }
1799 kq = NULL;
1800 }
1801 if ((lockflags & KNF_LISTLOCKED) == 0)
1802 list->kl_unlock(list->kl_lockarg);
1803 }
1804
1805 /*
1806 * add a knote to a knlist
1807 */
1808 void
1809 knlist_add(struct knlist *knl, struct knote *kn, int islocked)
1810 {
1811 KNL_ASSERT_LOCK(knl, islocked);
1812 KQ_NOTOWNED(kn->kn_kq);
1813 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) ==
1814 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED"));
1815 if (!islocked)
1816 knl->kl_lock(knl->kl_lockarg);
1817 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext);
1818 if (!islocked)
1819 knl->kl_unlock(knl->kl_lockarg);
1820 KQ_LOCK(kn->kn_kq);
1821 kn->kn_knlist = knl;
1822 kn->kn_status &= ~KN_DETACHED;
1823 KQ_UNLOCK(kn->kn_kq);
1824 }
1825
1826 static void
1827 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked)
1828 {
1829 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked"));
1830 KNL_ASSERT_LOCK(knl, knlislocked);
1831 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED);
1832 if (!kqislocked)
1833 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX,
1834 ("knlist_remove called w/o knote being KN_INFLUX or already removed"));
1835 if (!knlislocked)
1836 knl->kl_lock(knl->kl_lockarg);
1837 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
1838 kn->kn_knlist = NULL;
1839 if (!knlislocked)
1840 knl->kl_unlock(knl->kl_lockarg);
1841 if (!kqislocked)
1842 KQ_LOCK(kn->kn_kq);
1843 kn->kn_status |= KN_DETACHED;
1844 if (!kqislocked)
1845 KQ_UNLOCK(kn->kn_kq);
1846 }
1847
1848 /*
1849 * remove all knotes from a specified klist
1850 */
1851 void
1852 knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
1853 {
1854
1855 knlist_remove_kq(knl, kn, islocked, 0);
1856 }
1857
1858 /*
1859 * remove knote from a specified klist while in f_event handler.
1860 */
1861 void
1862 knlist_remove_inevent(struct knlist *knl, struct knote *kn)
1863 {
1864
1865 knlist_remove_kq(knl, kn, 1,
1866 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK);
1867 }
1868
1869 int
1870 knlist_empty(struct knlist *knl)
1871 {
1872 KNL_ASSERT_LOCKED(knl);
1873 return SLIST_EMPTY(&knl->kl_list);
1874 }
1875
1876 static struct mtx knlist_lock;
1877 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects",
1878 MTX_DEF);
1879 static void knlist_mtx_lock(void *arg);
1880 static void knlist_mtx_unlock(void *arg);
1881
1882 static void
1883 knlist_mtx_lock(void *arg)
1884 {
1885 mtx_lock((struct mtx *)arg);
1886 }
1887
1888 static void
1889 knlist_mtx_unlock(void *arg)
1890 {
1891 mtx_unlock((struct mtx *)arg);
1892 }
1893
1894 static void
1895 knlist_mtx_assert_locked(void *arg)
1896 {
1897 mtx_assert((struct mtx *)arg, MA_OWNED);
1898 }
1899
1900 static void
1901 knlist_mtx_assert_unlocked(void *arg)
1902 {
1903 mtx_assert((struct mtx *)arg, MA_NOTOWNED);
1904 }
1905
1906 void
1907 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
1908 void (*kl_unlock)(void *),
1909 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *))
1910 {
1911
1912 if (lock == NULL)
1913 knl->kl_lockarg = &knlist_lock;
1914 else
1915 knl->kl_lockarg = lock;
1916
1917 if (kl_lock == NULL)
1918 knl->kl_lock = knlist_mtx_lock;
1919 else
1920 knl->kl_lock = kl_lock;
1921 if (kl_unlock == NULL)
1922 knl->kl_unlock = knlist_mtx_unlock;
1923 else
1924 knl->kl_unlock = kl_unlock;
1925 if (kl_assert_locked == NULL)
1926 knl->kl_assert_locked = knlist_mtx_assert_locked;
1927 else
1928 knl->kl_assert_locked = kl_assert_locked;
1929 if (kl_assert_unlocked == NULL)
1930 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked;
1931 else
1932 knl->kl_assert_unlocked = kl_assert_unlocked;
1933
1934 SLIST_INIT(&knl->kl_list);
1935 }
1936
1937 void
1938 knlist_init_mtx(struct knlist *knl, struct mtx *lock)
1939 {
1940
1941 knlist_init(knl, lock, NULL, NULL, NULL, NULL);
1942 }
1943
1944 void
1945 knlist_destroy(struct knlist *knl)
1946 {
1947
1948 #ifdef INVARIANTS
1949 /*
1950 * if we run across this error, we need to find the offending
1951 * driver and have it call knlist_clear.
1952 */
1953 if (!SLIST_EMPTY(&knl->kl_list))
1954 printf("WARNING: destroying knlist w/ knotes on it!\n");
1955 #endif
1956
1957 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL;
1958 SLIST_INIT(&knl->kl_list);
1959 }
1960
1961 /*
1962 * Even if we are locked, we may need to drop the lock to allow any influx
1963 * knotes time to "settle".
1964 */
1965 void
1966 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
1967 {
1968 struct knote *kn, *kn2;
1969 struct kqueue *kq;
1970
1971 if (islocked)
1972 KNL_ASSERT_LOCKED(knl);
1973 else {
1974 KNL_ASSERT_UNLOCKED(knl);
1975 again: /* need to reacquire lock since we have dropped it */
1976 knl->kl_lock(knl->kl_lockarg);
1977 }
1978
1979 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
1980 kq = kn->kn_kq;
1981 KQ_LOCK(kq);
1982 if ((kn->kn_status & KN_INFLUX)) {
1983 KQ_UNLOCK(kq);
1984 continue;
1985 }
1986 knlist_remove_kq(knl, kn, 1, 1);
1987 if (killkn) {
1988 kn->kn_status |= KN_INFLUX | KN_DETACHED;
1989 KQ_UNLOCK(kq);
1990 knote_drop(kn, td);
1991 } else {
1992 /* Make sure cleared knotes disappear soon */
1993 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
1994 KQ_UNLOCK(kq);
1995 }
1996 kq = NULL;
1997 }
1998
1999 if (!SLIST_EMPTY(&knl->kl_list)) {
2000 /* there are still KN_INFLUX remaining */
2001 kn = SLIST_FIRST(&knl->kl_list);
2002 kq = kn->kn_kq;
2003 KQ_LOCK(kq);
2004 KASSERT(kn->kn_status & KN_INFLUX,
2005 ("knote removed w/o list lock"));
2006 knl->kl_unlock(knl->kl_lockarg);
2007 kq->kq_state |= KQ_FLUXWAIT;
2008 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
2009 kq = NULL;
2010 goto again;
2011 }
2012
2013 if (islocked)
2014 KNL_ASSERT_LOCKED(knl);
2015 else {
2016 knl->kl_unlock(knl->kl_lockarg);
2017 KNL_ASSERT_UNLOCKED(knl);
2018 }
2019 }
2020
2021 /*
2022 * Remove all knotes referencing a specified fd must be called with FILEDESC
2023 * lock. This prevents a race where a new fd comes along and occupies the
2024 * entry and we attach a knote to the fd.
2025 */
2026 void
2027 knote_fdclose(struct thread *td, int fd)
2028 {
2029 struct filedesc *fdp = td->td_proc->p_fd;
2030 struct kqueue *kq;
2031 struct knote *kn;
2032 int influx;
2033
2034 FILEDESC_XLOCK_ASSERT(fdp);
2035
2036 /*
2037 * We shouldn't have to worry about new kevents appearing on fd
2038 * since filedesc is locked.
2039 */
2040 SLIST_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
2041 KQ_LOCK(kq);
2042
2043 again:
2044 influx = 0;
2045 while (kq->kq_knlistsize > fd &&
2046 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
2047 if (kn->kn_status & KN_INFLUX) {
2048 /* someone else might be waiting on our knote */
2049 if (influx)
2050 wakeup(kq);
2051 kq->kq_state |= KQ_FLUXWAIT;
2052 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
2053 goto again;
2054 }
2055 kn->kn_status |= KN_INFLUX;
2056 KQ_UNLOCK(kq);
2057 if (!(kn->kn_status & KN_DETACHED))
2058 kn->kn_fop->f_detach(kn);
2059 knote_drop(kn, td);
2060 influx = 1;
2061 KQ_LOCK(kq);
2062 }
2063 KQ_UNLOCK_FLUX(kq);
2064 }
2065 }
2066
2067 static int
2068 knote_attach(struct knote *kn, struct kqueue *kq)
2069 {
2070 struct klist *list;
2071
2072 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX"));
2073 KQ_OWNED(kq);
2074
2075 if (kn->kn_fop->f_isfd) {
2076 if (kn->kn_id >= kq->kq_knlistsize)
2077 return ENOMEM;
2078 list = &kq->kq_knlist[kn->kn_id];
2079 } else {
2080 if (kq->kq_knhash == NULL)
2081 return ENOMEM;
2082 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2083 }
2084
2085 SLIST_INSERT_HEAD(list, kn, kn_link);
2086
2087 return 0;
2088 }
2089
2090 /*
2091 * knote must already have been detached using the f_detach method.
2092 * no lock need to be held, it is assumed that the KN_INFLUX flag is set
2093 * to prevent other removal.
2094 */
2095 static void
2096 knote_drop(struct knote *kn, struct thread *td)
2097 {
2098 struct kqueue *kq;
2099 struct klist *list;
2100
2101 kq = kn->kn_kq;
2102
2103 KQ_NOTOWNED(kq);
2104 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX,
2105 ("knote_drop called without KN_INFLUX set in kn_status"));
2106
2107 KQ_LOCK(kq);
2108 if (kn->kn_fop->f_isfd)
2109 list = &kq->kq_knlist[kn->kn_id];
2110 else
2111 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2112
2113 if (!SLIST_EMPTY(list))
2114 SLIST_REMOVE(list, kn, knote, kn_link);
2115 if (kn->kn_status & KN_QUEUED)
2116 knote_dequeue(kn);
2117 KQ_UNLOCK_FLUX(kq);
2118
2119 if (kn->kn_fop->f_isfd) {
2120 fdrop(kn->kn_fp, td);
2121 kn->kn_fp = NULL;
2122 }
2123 kqueue_fo_release(kn->kn_kevent.filter);
2124 kn->kn_fop = NULL;
2125 knote_free(kn);
2126 }
2127
2128 static void
2129 knote_enqueue(struct knote *kn)
2130 {
2131 struct kqueue *kq = kn->kn_kq;
2132
2133 KQ_OWNED(kn->kn_kq);
2134 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
2135
2136 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
2137 kn->kn_status |= KN_QUEUED;
2138 kq->kq_count++;
2139 kqueue_wakeup(kq);
2140 }
2141
2142 static void
2143 knote_dequeue(struct knote *kn)
2144 {
2145 struct kqueue *kq = kn->kn_kq;
2146
2147 KQ_OWNED(kn->kn_kq);
2148 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
2149
2150 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
2151 kn->kn_status &= ~KN_QUEUED;
2152 kq->kq_count--;
2153 }
2154
2155 static void
2156 knote_init(void)
2157 {
2158
2159 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
2160 NULL, NULL, UMA_ALIGN_PTR, 0);
2161 }
2162 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
2163
2164 static struct knote *
2165 knote_alloc(int waitok)
2166 {
2167 return ((struct knote *)uma_zalloc(knote_zone,
2168 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO));
2169 }
2170
2171 static void
2172 knote_free(struct knote *kn)
2173 {
2174 if (kn != NULL)
2175 uma_zfree(knote_zone, kn);
2176 }
2177
2178 /*
2179 * Register the kev w/ the kq specified by fd.
2180 */
2181 int
2182 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok)
2183 {
2184 struct kqueue *kq;
2185 struct file *fp;
2186 int error;
2187
2188 if ((error = fget(td, fd, CAP_POST_EVENT, &fp)) != 0)
2189 return (error);
2190 if ((error = kqueue_acquire(fp, &kq)) != 0)
2191 goto noacquire;
2192
2193 error = kqueue_register(kq, kev, td, waitok);
2194
2195 kqueue_release(kq, 0);
2196
2197 noacquire:
2198 fdrop(fp, td);
2199
2200 return error;
2201 }
Cache object: 257cc91bda993284a0f7bedaab8e581e
|