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/10.1/sys/kern/kern_event.c 264368 2014-04-12 14:08:53Z kib $");
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/rwlock.h>
41 #include <sys/proc.h>
42 #include <sys/malloc.h>
43 #include <sys/unistd.h>
44 #include <sys/file.h>
45 #include <sys/filedesc.h>
46 #include <sys/filio.h>
47 #include <sys/fcntl.h>
48 #include <sys/kthread.h>
49 #include <sys/selinfo.h>
50 #include <sys/stdatomic.h>
51 #include <sys/queue.h>
52 #include <sys/event.h>
53 #include <sys/eventvar.h>
54 #include <sys/poll.h>
55 #include <sys/protosw.h>
56 #include <sys/sigio.h>
57 #include <sys/signalvar.h>
58 #include <sys/socket.h>
59 #include <sys/socketvar.h>
60 #include <sys/stat.h>
61 #include <sys/sysctl.h>
62 #include <sys/sysproto.h>
63 #include <sys/syscallsubr.h>
64 #include <sys/taskqueue.h>
65 #include <sys/uio.h>
66 #ifdef KTRACE
67 #include <sys/ktrace.h>
68 #endif
69
70 #include <vm/uma.h>
71
72 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
73
74 /*
75 * This lock is used if multiple kq locks are required. This possibly
76 * should be made into a per proc lock.
77 */
78 static struct mtx kq_global;
79 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF);
80 #define KQ_GLOBAL_LOCK(lck, haslck) do { \
81 if (!haslck) \
82 mtx_lock(lck); \
83 haslck = 1; \
84 } while (0)
85 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \
86 if (haslck) \
87 mtx_unlock(lck); \
88 haslck = 0; \
89 } while (0)
90
91 TASKQUEUE_DEFINE_THREAD(kqueue);
92
93 static int kevent_copyout(void *arg, struct kevent *kevp, int count);
94 static int kevent_copyin(void *arg, struct kevent *kevp, int count);
95 static int kqueue_register(struct kqueue *kq, struct kevent *kev,
96 struct thread *td, int waitok);
97 static int kqueue_acquire(struct file *fp, struct kqueue **kqp);
98 static void kqueue_release(struct kqueue *kq, int locked);
99 static int kqueue_expand(struct kqueue *kq, struct filterops *fops,
100 uintptr_t ident, int waitok);
101 static void kqueue_task(void *arg, int pending);
102 static int kqueue_scan(struct kqueue *kq, int maxevents,
103 struct kevent_copyops *k_ops,
104 const struct timespec *timeout,
105 struct kevent *keva, struct thread *td);
106 static void kqueue_wakeup(struct kqueue *kq);
107 static struct filterops *kqueue_fo_find(int filt);
108 static void kqueue_fo_release(int filt);
109
110 static fo_rdwr_t kqueue_read;
111 static fo_rdwr_t kqueue_write;
112 static fo_truncate_t kqueue_truncate;
113 static fo_ioctl_t kqueue_ioctl;
114 static fo_poll_t kqueue_poll;
115 static fo_kqfilter_t kqueue_kqfilter;
116 static fo_stat_t kqueue_stat;
117 static fo_close_t kqueue_close;
118
119 static struct fileops kqueueops = {
120 .fo_read = kqueue_read,
121 .fo_write = kqueue_write,
122 .fo_truncate = kqueue_truncate,
123 .fo_ioctl = kqueue_ioctl,
124 .fo_poll = kqueue_poll,
125 .fo_kqfilter = kqueue_kqfilter,
126 .fo_stat = kqueue_stat,
127 .fo_close = kqueue_close,
128 .fo_chmod = invfo_chmod,
129 .fo_chown = invfo_chown,
130 .fo_sendfile = invfo_sendfile,
131 };
132
133 static int knote_attach(struct knote *kn, struct kqueue *kq);
134 static void knote_drop(struct knote *kn, struct thread *td);
135 static void knote_enqueue(struct knote *kn);
136 static void knote_dequeue(struct knote *kn);
137 static void knote_init(void);
138 static struct knote *knote_alloc(int waitok);
139 static void knote_free(struct knote *kn);
140
141 static void filt_kqdetach(struct knote *kn);
142 static int filt_kqueue(struct knote *kn, long hint);
143 static int filt_procattach(struct knote *kn);
144 static void filt_procdetach(struct knote *kn);
145 static int filt_proc(struct knote *kn, long hint);
146 static int filt_fileattach(struct knote *kn);
147 static void filt_timerexpire(void *knx);
148 static int filt_timerattach(struct knote *kn);
149 static void filt_timerdetach(struct knote *kn);
150 static int filt_timer(struct knote *kn, long hint);
151 static int filt_userattach(struct knote *kn);
152 static void filt_userdetach(struct knote *kn);
153 static int filt_user(struct knote *kn, long hint);
154 static void filt_usertouch(struct knote *kn, struct kevent *kev,
155 u_long type);
156
157 static struct filterops file_filtops = {
158 .f_isfd = 1,
159 .f_attach = filt_fileattach,
160 };
161 static struct filterops kqread_filtops = {
162 .f_isfd = 1,
163 .f_detach = filt_kqdetach,
164 .f_event = filt_kqueue,
165 };
166 /* XXX - move to kern_proc.c? */
167 static struct filterops proc_filtops = {
168 .f_isfd = 0,
169 .f_attach = filt_procattach,
170 .f_detach = filt_procdetach,
171 .f_event = filt_proc,
172 };
173 static struct filterops timer_filtops = {
174 .f_isfd = 0,
175 .f_attach = filt_timerattach,
176 .f_detach = filt_timerdetach,
177 .f_event = filt_timer,
178 };
179 static struct filterops user_filtops = {
180 .f_attach = filt_userattach,
181 .f_detach = filt_userdetach,
182 .f_event = filt_user,
183 .f_touch = filt_usertouch,
184 };
185
186 static uma_zone_t knote_zone;
187 static atomic_uint kq_ncallouts = ATOMIC_VAR_INIT(0);
188 static unsigned int kq_calloutmax = 4 * 1024;
189 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
190 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
191
192 /* XXX - ensure not KN_INFLUX?? */
193 #define KNOTE_ACTIVATE(kn, islock) do { \
194 if ((islock)) \
195 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \
196 else \
197 KQ_LOCK((kn)->kn_kq); \
198 (kn)->kn_status |= KN_ACTIVE; \
199 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
200 knote_enqueue((kn)); \
201 if (!(islock)) \
202 KQ_UNLOCK((kn)->kn_kq); \
203 } while(0)
204 #define KQ_LOCK(kq) do { \
205 mtx_lock(&(kq)->kq_lock); \
206 } while (0)
207 #define KQ_FLUX_WAKEUP(kq) do { \
208 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \
209 (kq)->kq_state &= ~KQ_FLUXWAIT; \
210 wakeup((kq)); \
211 } \
212 } while (0)
213 #define KQ_UNLOCK_FLUX(kq) do { \
214 KQ_FLUX_WAKEUP(kq); \
215 mtx_unlock(&(kq)->kq_lock); \
216 } while (0)
217 #define KQ_UNLOCK(kq) do { \
218 mtx_unlock(&(kq)->kq_lock); \
219 } while (0)
220 #define KQ_OWNED(kq) do { \
221 mtx_assert(&(kq)->kq_lock, MA_OWNED); \
222 } while (0)
223 #define KQ_NOTOWNED(kq) do { \
224 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \
225 } while (0)
226 #define KN_LIST_LOCK(kn) do { \
227 if (kn->kn_knlist != NULL) \
228 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \
229 } while (0)
230 #define KN_LIST_UNLOCK(kn) do { \
231 if (kn->kn_knlist != NULL) \
232 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \
233 } while (0)
234 #define KNL_ASSERT_LOCK(knl, islocked) do { \
235 if (islocked) \
236 KNL_ASSERT_LOCKED(knl); \
237 else \
238 KNL_ASSERT_UNLOCKED(knl); \
239 } while (0)
240 #ifdef INVARIANTS
241 #define KNL_ASSERT_LOCKED(knl) do { \
242 knl->kl_assert_locked((knl)->kl_lockarg); \
243 } while (0)
244 #define KNL_ASSERT_UNLOCKED(knl) do { \
245 knl->kl_assert_unlocked((knl)->kl_lockarg); \
246 } while (0)
247 #else /* !INVARIANTS */
248 #define KNL_ASSERT_LOCKED(knl) do {} while(0)
249 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
250 #endif /* INVARIANTS */
251
252 #define KN_HASHSIZE 64 /* XXX should be tunable */
253 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
254
255 static int
256 filt_nullattach(struct knote *kn)
257 {
258
259 return (ENXIO);
260 };
261
262 struct filterops null_filtops = {
263 .f_isfd = 0,
264 .f_attach = filt_nullattach,
265 };
266
267 /* XXX - make SYSINIT to add these, and move into respective modules. */
268 extern struct filterops sig_filtops;
269 extern struct filterops fs_filtops;
270
271 /*
272 * Table for for all system-defined filters.
273 */
274 static struct mtx filterops_lock;
275 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops",
276 MTX_DEF);
277 static struct {
278 struct filterops *for_fop;
279 int for_refcnt;
280 } sysfilt_ops[EVFILT_SYSCOUNT] = {
281 { &file_filtops }, /* EVFILT_READ */
282 { &file_filtops }, /* EVFILT_WRITE */
283 { &null_filtops }, /* EVFILT_AIO */
284 { &file_filtops }, /* EVFILT_VNODE */
285 { &proc_filtops }, /* EVFILT_PROC */
286 { &sig_filtops }, /* EVFILT_SIGNAL */
287 { &timer_filtops }, /* EVFILT_TIMER */
288 { &null_filtops }, /* former EVFILT_NETDEV */
289 { &fs_filtops }, /* EVFILT_FS */
290 { &null_filtops }, /* EVFILT_LIO */
291 { &user_filtops }, /* EVFILT_USER */
292 };
293
294 /*
295 * Simple redirection for all cdevsw style objects to call their fo_kqfilter
296 * method.
297 */
298 static int
299 filt_fileattach(struct knote *kn)
300 {
301
302 return (fo_kqfilter(kn->kn_fp, kn));
303 }
304
305 /*ARGSUSED*/
306 static int
307 kqueue_kqfilter(struct file *fp, struct knote *kn)
308 {
309 struct kqueue *kq = kn->kn_fp->f_data;
310
311 if (kn->kn_filter != EVFILT_READ)
312 return (EINVAL);
313
314 kn->kn_status |= KN_KQUEUE;
315 kn->kn_fop = &kqread_filtops;
316 knlist_add(&kq->kq_sel.si_note, kn, 0);
317
318 return (0);
319 }
320
321 static void
322 filt_kqdetach(struct knote *kn)
323 {
324 struct kqueue *kq = kn->kn_fp->f_data;
325
326 knlist_remove(&kq->kq_sel.si_note, kn, 0);
327 }
328
329 /*ARGSUSED*/
330 static int
331 filt_kqueue(struct knote *kn, long hint)
332 {
333 struct kqueue *kq = kn->kn_fp->f_data;
334
335 kn->kn_data = kq->kq_count;
336 return (kn->kn_data > 0);
337 }
338
339 /* XXX - move to kern_proc.c? */
340 static int
341 filt_procattach(struct knote *kn)
342 {
343 struct proc *p;
344 int immediate;
345 int error;
346
347 immediate = 0;
348 p = pfind(kn->kn_id);
349 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
350 p = zpfind(kn->kn_id);
351 immediate = 1;
352 } else if (p != NULL && (p->p_flag & P_WEXIT)) {
353 immediate = 1;
354 }
355
356 if (p == NULL)
357 return (ESRCH);
358 if ((error = p_cansee(curthread, p))) {
359 PROC_UNLOCK(p);
360 return (error);
361 }
362
363 kn->kn_ptr.p_proc = p;
364 kn->kn_flags |= EV_CLEAR; /* automatically set */
365
366 /*
367 * internal flag indicating registration done by kernel
368 */
369 if (kn->kn_flags & EV_FLAG1) {
370 kn->kn_data = kn->kn_sdata; /* ppid */
371 kn->kn_fflags = NOTE_CHILD;
372 kn->kn_flags &= ~EV_FLAG1;
373 }
374
375 if (immediate == 0)
376 knlist_add(&p->p_klist, kn, 1);
377
378 /*
379 * Immediately activate any exit notes if the target process is a
380 * zombie. This is necessary to handle the case where the target
381 * process, e.g. a child, dies before the kevent is registered.
382 */
383 if (immediate && filt_proc(kn, NOTE_EXIT))
384 KNOTE_ACTIVATE(kn, 0);
385
386 PROC_UNLOCK(p);
387
388 return (0);
389 }
390
391 /*
392 * The knote may be attached to a different process, which may exit,
393 * leaving nothing for the knote to be attached to. So when the process
394 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
395 * it will be deleted when read out. However, as part of the knote deletion,
396 * this routine is called, so a check is needed to avoid actually performing
397 * a detach, because the original process does not exist any more.
398 */
399 /* XXX - move to kern_proc.c? */
400 static void
401 filt_procdetach(struct knote *kn)
402 {
403 struct proc *p;
404
405 p = kn->kn_ptr.p_proc;
406 knlist_remove(&p->p_klist, kn, 0);
407 kn->kn_ptr.p_proc = NULL;
408 }
409
410 /* XXX - move to kern_proc.c? */
411 static int
412 filt_proc(struct knote *kn, long hint)
413 {
414 struct proc *p = kn->kn_ptr.p_proc;
415 u_int event;
416
417 /*
418 * mask off extra data
419 */
420 event = (u_int)hint & NOTE_PCTRLMASK;
421
422 /*
423 * if the user is interested in this event, record it.
424 */
425 if (kn->kn_sfflags & event)
426 kn->kn_fflags |= event;
427
428 /*
429 * process is gone, so flag the event as finished.
430 */
431 if (event == NOTE_EXIT) {
432 if (!(kn->kn_status & KN_DETACHED))
433 knlist_remove_inevent(&p->p_klist, kn);
434 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
435 kn->kn_ptr.p_proc = NULL;
436 if (kn->kn_fflags & NOTE_EXIT)
437 kn->kn_data = p->p_xstat;
438 if (kn->kn_fflags == 0)
439 kn->kn_flags |= EV_DROP;
440 return (1);
441 }
442
443 return (kn->kn_fflags != 0);
444 }
445
446 /*
447 * Called when the process forked. It mostly does the same as the
448 * knote(), activating all knotes registered to be activated when the
449 * process forked. Additionally, for each knote attached to the
450 * parent, check whether user wants to track the new process. If so
451 * attach a new knote to it, and immediately report an event with the
452 * child's pid.
453 */
454 void
455 knote_fork(struct knlist *list, int pid)
456 {
457 struct kqueue *kq;
458 struct knote *kn;
459 struct kevent kev;
460 int error;
461
462 if (list == NULL)
463 return;
464 list->kl_lock(list->kl_lockarg);
465
466 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
467 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX)
468 continue;
469 kq = kn->kn_kq;
470 KQ_LOCK(kq);
471 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) {
472 KQ_UNLOCK(kq);
473 continue;
474 }
475
476 /*
477 * The same as knote(), activate the event.
478 */
479 if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
480 kn->kn_status |= KN_HASKQLOCK;
481 if (kn->kn_fop->f_event(kn, NOTE_FORK))
482 KNOTE_ACTIVATE(kn, 1);
483 kn->kn_status &= ~KN_HASKQLOCK;
484 KQ_UNLOCK(kq);
485 continue;
486 }
487
488 /*
489 * The NOTE_TRACK case. In addition to the activation
490 * of the event, we need to register new event to
491 * track the child. Drop the locks in preparation for
492 * the call to kqueue_register().
493 */
494 kn->kn_status |= KN_INFLUX;
495 KQ_UNLOCK(kq);
496 list->kl_unlock(list->kl_lockarg);
497
498 /*
499 * Activate existing knote and register a knote with
500 * new process.
501 */
502 kev.ident = pid;
503 kev.filter = kn->kn_filter;
504 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
505 kev.fflags = kn->kn_sfflags;
506 kev.data = kn->kn_id; /* parent */
507 kev.udata = kn->kn_kevent.udata;/* preserve udata */
508 error = kqueue_register(kq, &kev, NULL, 0);
509 if (error)
510 kn->kn_fflags |= NOTE_TRACKERR;
511 if (kn->kn_fop->f_event(kn, NOTE_FORK))
512 KNOTE_ACTIVATE(kn, 0);
513 KQ_LOCK(kq);
514 kn->kn_status &= ~KN_INFLUX;
515 KQ_UNLOCK_FLUX(kq);
516 list->kl_lock(list->kl_lockarg);
517 }
518 list->kl_unlock(list->kl_lockarg);
519 }
520
521 /*
522 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the
523 * interval timer support code.
524 */
525 static __inline sbintime_t
526 timer2sbintime(intptr_t data)
527 {
528
529 return (SBT_1MS * data);
530 }
531
532 static void
533 filt_timerexpire(void *knx)
534 {
535 struct callout *calloutp;
536 struct knote *kn;
537
538 kn = knx;
539 kn->kn_data++;
540 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
541
542 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) {
543 calloutp = (struct callout *)kn->kn_hook;
544 callout_reset_sbt_on(calloutp,
545 timer2sbintime(kn->kn_sdata), 0 /* 1ms? */,
546 filt_timerexpire, kn, PCPU_GET(cpuid), 0);
547 }
548 }
549
550 /*
551 * data contains amount of time to sleep, in milliseconds
552 */
553 static int
554 filt_timerattach(struct knote *kn)
555 {
556 struct callout *calloutp;
557 sbintime_t to;
558 unsigned int ncallouts;
559
560 if ((intptr_t)kn->kn_sdata < 0)
561 return (EINVAL);
562 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0)
563 kn->kn_sdata = 1;
564 to = timer2sbintime(kn->kn_sdata);
565 if (to < 0)
566 return (EINVAL);
567
568 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed);
569 do {
570 if (ncallouts >= kq_calloutmax)
571 return (ENOMEM);
572 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts,
573 &ncallouts, ncallouts + 1, memory_order_relaxed,
574 memory_order_relaxed));
575
576 kn->kn_flags |= EV_CLEAR; /* automatically set */
577 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */
578 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK);
579 callout_init(calloutp, CALLOUT_MPSAFE);
580 kn->kn_hook = calloutp;
581 callout_reset_sbt_on(calloutp, to, 0 /* 1ms? */,
582 filt_timerexpire, kn, PCPU_GET(cpuid), 0);
583
584 return (0);
585 }
586
587 static void
588 filt_timerdetach(struct knote *kn)
589 {
590 struct callout *calloutp;
591 unsigned int old;
592
593 calloutp = (struct callout *)kn->kn_hook;
594 callout_drain(calloutp);
595 free(calloutp, M_KQUEUE);
596 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed);
597 KASSERT(old > 0, ("Number of callouts cannot become negative"));
598 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */
599 }
600
601 static int
602 filt_timer(struct knote *kn, long hint)
603 {
604
605 return (kn->kn_data != 0);
606 }
607
608 static int
609 filt_userattach(struct knote *kn)
610 {
611
612 /*
613 * EVFILT_USER knotes are not attached to anything in the kernel.
614 */
615 kn->kn_hook = NULL;
616 if (kn->kn_fflags & NOTE_TRIGGER)
617 kn->kn_hookid = 1;
618 else
619 kn->kn_hookid = 0;
620 return (0);
621 }
622
623 static void
624 filt_userdetach(__unused struct knote *kn)
625 {
626
627 /*
628 * EVFILT_USER knotes are not attached to anything in the kernel.
629 */
630 }
631
632 static int
633 filt_user(struct knote *kn, __unused long hint)
634 {
635
636 return (kn->kn_hookid);
637 }
638
639 static void
640 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
641 {
642 u_int ffctrl;
643
644 switch (type) {
645 case EVENT_REGISTER:
646 if (kev->fflags & NOTE_TRIGGER)
647 kn->kn_hookid = 1;
648
649 ffctrl = kev->fflags & NOTE_FFCTRLMASK;
650 kev->fflags &= NOTE_FFLAGSMASK;
651 switch (ffctrl) {
652 case NOTE_FFNOP:
653 break;
654
655 case NOTE_FFAND:
656 kn->kn_sfflags &= kev->fflags;
657 break;
658
659 case NOTE_FFOR:
660 kn->kn_sfflags |= kev->fflags;
661 break;
662
663 case NOTE_FFCOPY:
664 kn->kn_sfflags = kev->fflags;
665 break;
666
667 default:
668 /* XXX Return error? */
669 break;
670 }
671 kn->kn_sdata = kev->data;
672 if (kev->flags & EV_CLEAR) {
673 kn->kn_hookid = 0;
674 kn->kn_data = 0;
675 kn->kn_fflags = 0;
676 }
677 break;
678
679 case EVENT_PROCESS:
680 *kev = kn->kn_kevent;
681 kev->fflags = kn->kn_sfflags;
682 kev->data = kn->kn_sdata;
683 if (kn->kn_flags & EV_CLEAR) {
684 kn->kn_hookid = 0;
685 kn->kn_data = 0;
686 kn->kn_fflags = 0;
687 }
688 break;
689
690 default:
691 panic("filt_usertouch() - invalid type (%ld)", type);
692 break;
693 }
694 }
695
696 int
697 sys_kqueue(struct thread *td, struct kqueue_args *uap)
698 {
699 struct filedesc *fdp;
700 struct kqueue *kq;
701 struct file *fp;
702 int fd, error;
703
704 fdp = td->td_proc->p_fd;
705 error = falloc(td, &fp, &fd, 0);
706 if (error)
707 goto done2;
708
709 /* An extra reference on `fp' has been held for us by falloc(). */
710 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
711 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK);
712 TAILQ_INIT(&kq->kq_head);
713 kq->kq_fdp = fdp;
714 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
715 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
716
717 FILEDESC_XLOCK(fdp);
718 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
719 FILEDESC_XUNLOCK(fdp);
720
721 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
722 fdrop(fp, td);
723
724 td->td_retval[0] = fd;
725 done2:
726 return (error);
727 }
728
729 #ifndef _SYS_SYSPROTO_H_
730 struct kevent_args {
731 int fd;
732 const struct kevent *changelist;
733 int nchanges;
734 struct kevent *eventlist;
735 int nevents;
736 const struct timespec *timeout;
737 };
738 #endif
739 int
740 sys_kevent(struct thread *td, struct kevent_args *uap)
741 {
742 struct timespec ts, *tsp;
743 struct kevent_copyops k_ops = { uap,
744 kevent_copyout,
745 kevent_copyin};
746 int error;
747 #ifdef KTRACE
748 struct uio ktruio;
749 struct iovec ktriov;
750 struct uio *ktruioin = NULL;
751 struct uio *ktruioout = NULL;
752 #endif
753
754 if (uap->timeout != NULL) {
755 error = copyin(uap->timeout, &ts, sizeof(ts));
756 if (error)
757 return (error);
758 tsp = &ts;
759 } else
760 tsp = NULL;
761
762 #ifdef KTRACE
763 if (KTRPOINT(td, KTR_GENIO)) {
764 ktriov.iov_base = uap->changelist;
765 ktriov.iov_len = uap->nchanges * sizeof(struct kevent);
766 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1,
767 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ,
768 .uio_td = td };
769 ktruioin = cloneuio(&ktruio);
770 ktriov.iov_base = uap->eventlist;
771 ktriov.iov_len = uap->nevents * sizeof(struct kevent);
772 ktruioout = cloneuio(&ktruio);
773 }
774 #endif
775
776 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
777 &k_ops, tsp);
778
779 #ifdef KTRACE
780 if (ktruioin != NULL) {
781 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent);
782 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0);
783 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent);
784 ktrgenio(uap->fd, UIO_READ, ktruioout, error);
785 }
786 #endif
787
788 return (error);
789 }
790
791 /*
792 * Copy 'count' items into the destination list pointed to by uap->eventlist.
793 */
794 static int
795 kevent_copyout(void *arg, struct kevent *kevp, int count)
796 {
797 struct kevent_args *uap;
798 int error;
799
800 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
801 uap = (struct kevent_args *)arg;
802
803 error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
804 if (error == 0)
805 uap->eventlist += count;
806 return (error);
807 }
808
809 /*
810 * Copy 'count' items from the list pointed to by uap->changelist.
811 */
812 static int
813 kevent_copyin(void *arg, struct kevent *kevp, int count)
814 {
815 struct kevent_args *uap;
816 int error;
817
818 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
819 uap = (struct kevent_args *)arg;
820
821 error = copyin(uap->changelist, kevp, count * sizeof *kevp);
822 if (error == 0)
823 uap->changelist += count;
824 return (error);
825 }
826
827 int
828 kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
829 struct kevent_copyops *k_ops, const struct timespec *timeout)
830 {
831 struct kevent keva[KQ_NEVENTS];
832 struct kevent *kevp, *changes;
833 struct kqueue *kq;
834 struct file *fp;
835 cap_rights_t rights;
836 int i, n, nerrors, error;
837
838 cap_rights_init(&rights);
839 if (nchanges > 0)
840 cap_rights_set(&rights, CAP_KQUEUE_CHANGE);
841 if (nevents > 0)
842 cap_rights_set(&rights, CAP_KQUEUE_EVENT);
843 error = fget(td, fd, &rights, &fp);
844 if (error != 0)
845 return (error);
846
847 error = kqueue_acquire(fp, &kq);
848 if (error != 0)
849 goto done_norel;
850
851 nerrors = 0;
852
853 while (nchanges > 0) {
854 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
855 error = k_ops->k_copyin(k_ops->arg, keva, n);
856 if (error)
857 goto done;
858 changes = keva;
859 for (i = 0; i < n; i++) {
860 kevp = &changes[i];
861 if (!kevp->filter)
862 continue;
863 kevp->flags &= ~EV_SYSFLAGS;
864 error = kqueue_register(kq, kevp, td, 1);
865 if (error || (kevp->flags & EV_RECEIPT)) {
866 if (nevents != 0) {
867 kevp->flags = EV_ERROR;
868 kevp->data = error;
869 (void) k_ops->k_copyout(k_ops->arg,
870 kevp, 1);
871 nevents--;
872 nerrors++;
873 } else {
874 goto done;
875 }
876 }
877 }
878 nchanges -= n;
879 }
880 if (nerrors) {
881 td->td_retval[0] = nerrors;
882 error = 0;
883 goto done;
884 }
885
886 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td);
887 done:
888 kqueue_release(kq, 0);
889 done_norel:
890 fdrop(fp, td);
891 return (error);
892 }
893
894 int
895 kqueue_add_filteropts(int filt, struct filterops *filtops)
896 {
897 int error;
898
899 error = 0;
900 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
901 printf(
902 "trying to add a filterop that is out of range: %d is beyond %d\n",
903 ~filt, EVFILT_SYSCOUNT);
904 return EINVAL;
905 }
906 mtx_lock(&filterops_lock);
907 if (sysfilt_ops[~filt].for_fop != &null_filtops &&
908 sysfilt_ops[~filt].for_fop != NULL)
909 error = EEXIST;
910 else {
911 sysfilt_ops[~filt].for_fop = filtops;
912 sysfilt_ops[~filt].for_refcnt = 0;
913 }
914 mtx_unlock(&filterops_lock);
915
916 return (error);
917 }
918
919 int
920 kqueue_del_filteropts(int filt)
921 {
922 int error;
923
924 error = 0;
925 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
926 return EINVAL;
927
928 mtx_lock(&filterops_lock);
929 if (sysfilt_ops[~filt].for_fop == &null_filtops ||
930 sysfilt_ops[~filt].for_fop == NULL)
931 error = EINVAL;
932 else if (sysfilt_ops[~filt].for_refcnt != 0)
933 error = EBUSY;
934 else {
935 sysfilt_ops[~filt].for_fop = &null_filtops;
936 sysfilt_ops[~filt].for_refcnt = 0;
937 }
938 mtx_unlock(&filterops_lock);
939
940 return error;
941 }
942
943 static struct filterops *
944 kqueue_fo_find(int filt)
945 {
946
947 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
948 return NULL;
949
950 mtx_lock(&filterops_lock);
951 sysfilt_ops[~filt].for_refcnt++;
952 if (sysfilt_ops[~filt].for_fop == NULL)
953 sysfilt_ops[~filt].for_fop = &null_filtops;
954 mtx_unlock(&filterops_lock);
955
956 return sysfilt_ops[~filt].for_fop;
957 }
958
959 static void
960 kqueue_fo_release(int filt)
961 {
962
963 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
964 return;
965
966 mtx_lock(&filterops_lock);
967 KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
968 ("filter object refcount not valid on release"));
969 sysfilt_ops[~filt].for_refcnt--;
970 mtx_unlock(&filterops_lock);
971 }
972
973 /*
974 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will
975 * influence if memory allocation should wait. Make sure it is 0 if you
976 * hold any mutexes.
977 */
978 static int
979 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok)
980 {
981 struct filterops *fops;
982 struct file *fp;
983 struct knote *kn, *tkn;
984 cap_rights_t rights;
985 int error, filt, event;
986 int haskqglobal, filedesc_unlock;
987
988 fp = NULL;
989 kn = NULL;
990 error = 0;
991 haskqglobal = 0;
992 filedesc_unlock = 0;
993
994 filt = kev->filter;
995 fops = kqueue_fo_find(filt);
996 if (fops == NULL)
997 return EINVAL;
998
999 tkn = knote_alloc(waitok); /* prevent waiting with locks */
1000
1001 findkn:
1002 if (fops->f_isfd) {
1003 KASSERT(td != NULL, ("td is NULL"));
1004 error = fget(td, kev->ident,
1005 cap_rights_init(&rights, CAP_EVENT), &fp);
1006 if (error)
1007 goto done;
1008
1009 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
1010 kev->ident, 0) != 0) {
1011 /* try again */
1012 fdrop(fp, td);
1013 fp = NULL;
1014 error = kqueue_expand(kq, fops, kev->ident, waitok);
1015 if (error)
1016 goto done;
1017 goto findkn;
1018 }
1019
1020 if (fp->f_type == DTYPE_KQUEUE) {
1021 /*
1022 * if we add some inteligence about what we are doing,
1023 * we should be able to support events on ourselves.
1024 * We need to know when we are doing this to prevent
1025 * getting both the knlist lock and the kq lock since
1026 * they are the same thing.
1027 */
1028 if (fp->f_data == kq) {
1029 error = EINVAL;
1030 goto done;
1031 }
1032
1033 /*
1034 * Pre-lock the filedesc before the global
1035 * lock mutex, see the comment in
1036 * kqueue_close().
1037 */
1038 FILEDESC_XLOCK(td->td_proc->p_fd);
1039 filedesc_unlock = 1;
1040 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1041 }
1042
1043 KQ_LOCK(kq);
1044 if (kev->ident < kq->kq_knlistsize) {
1045 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
1046 if (kev->filter == kn->kn_filter)
1047 break;
1048 }
1049 } else {
1050 if ((kev->flags & EV_ADD) == EV_ADD)
1051 kqueue_expand(kq, fops, kev->ident, waitok);
1052
1053 KQ_LOCK(kq);
1054 if (kq->kq_knhashmask != 0) {
1055 struct klist *list;
1056
1057 list = &kq->kq_knhash[
1058 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
1059 SLIST_FOREACH(kn, list, kn_link)
1060 if (kev->ident == kn->kn_id &&
1061 kev->filter == kn->kn_filter)
1062 break;
1063 }
1064 }
1065
1066 /* knote is in the process of changing, wait for it to stablize. */
1067 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1068 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1069 if (filedesc_unlock) {
1070 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1071 filedesc_unlock = 0;
1072 }
1073 kq->kq_state |= KQ_FLUXWAIT;
1074 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
1075 if (fp != NULL) {
1076 fdrop(fp, td);
1077 fp = NULL;
1078 }
1079 goto findkn;
1080 }
1081
1082 /*
1083 * kn now contains the matching knote, or NULL if no match
1084 */
1085 if (kn == NULL) {
1086 if (kev->flags & EV_ADD) {
1087 kn = tkn;
1088 tkn = NULL;
1089 if (kn == NULL) {
1090 KQ_UNLOCK(kq);
1091 error = ENOMEM;
1092 goto done;
1093 }
1094 kn->kn_fp = fp;
1095 kn->kn_kq = kq;
1096 kn->kn_fop = fops;
1097 /*
1098 * apply reference counts to knote structure, and
1099 * do not release it at the end of this routine.
1100 */
1101 fops = NULL;
1102 fp = NULL;
1103
1104 kn->kn_sfflags = kev->fflags;
1105 kn->kn_sdata = kev->data;
1106 kev->fflags = 0;
1107 kev->data = 0;
1108 kn->kn_kevent = *kev;
1109 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
1110 EV_ENABLE | EV_DISABLE);
1111 kn->kn_status = KN_INFLUX|KN_DETACHED;
1112
1113 error = knote_attach(kn, kq);
1114 KQ_UNLOCK(kq);
1115 if (error != 0) {
1116 tkn = kn;
1117 goto done;
1118 }
1119
1120 if ((error = kn->kn_fop->f_attach(kn)) != 0) {
1121 knote_drop(kn, td);
1122 goto done;
1123 }
1124 KN_LIST_LOCK(kn);
1125 goto done_ev_add;
1126 } else {
1127 /* No matching knote and the EV_ADD flag is not set. */
1128 KQ_UNLOCK(kq);
1129 error = ENOENT;
1130 goto done;
1131 }
1132 }
1133
1134 if (kev->flags & EV_DELETE) {
1135 kn->kn_status |= KN_INFLUX;
1136 KQ_UNLOCK(kq);
1137 if (!(kn->kn_status & KN_DETACHED))
1138 kn->kn_fop->f_detach(kn);
1139 knote_drop(kn, td);
1140 goto done;
1141 }
1142
1143 /*
1144 * The user may change some filter values after the initial EV_ADD,
1145 * but doing so will not reset any filter which has already been
1146 * triggered.
1147 */
1148 kn->kn_status |= KN_INFLUX | KN_SCAN;
1149 KQ_UNLOCK(kq);
1150 KN_LIST_LOCK(kn);
1151 kn->kn_kevent.udata = kev->udata;
1152 if (!fops->f_isfd && fops->f_touch != NULL) {
1153 fops->f_touch(kn, kev, EVENT_REGISTER);
1154 } else {
1155 kn->kn_sfflags = kev->fflags;
1156 kn->kn_sdata = kev->data;
1157 }
1158
1159 /*
1160 * We can get here with kn->kn_knlist == NULL. This can happen when
1161 * the initial attach event decides that the event is "completed"
1162 * already. i.e. filt_procattach is called on a zombie process. It
1163 * will call filt_proc which will remove it from the list, and NULL
1164 * kn_knlist.
1165 */
1166 done_ev_add:
1167 event = kn->kn_fop->f_event(kn, 0);
1168 KQ_LOCK(kq);
1169 if (event)
1170 KNOTE_ACTIVATE(kn, 1);
1171 kn->kn_status &= ~(KN_INFLUX | KN_SCAN);
1172 KN_LIST_UNLOCK(kn);
1173
1174 if ((kev->flags & EV_DISABLE) &&
1175 ((kn->kn_status & KN_DISABLED) == 0)) {
1176 kn->kn_status |= KN_DISABLED;
1177 }
1178
1179 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
1180 kn->kn_status &= ~KN_DISABLED;
1181 if ((kn->kn_status & KN_ACTIVE) &&
1182 ((kn->kn_status & KN_QUEUED) == 0))
1183 knote_enqueue(kn);
1184 }
1185 KQ_UNLOCK_FLUX(kq);
1186
1187 done:
1188 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1189 if (filedesc_unlock)
1190 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1191 if (fp != NULL)
1192 fdrop(fp, td);
1193 if (tkn != NULL)
1194 knote_free(tkn);
1195 if (fops != NULL)
1196 kqueue_fo_release(filt);
1197 return (error);
1198 }
1199
1200 static int
1201 kqueue_acquire(struct file *fp, struct kqueue **kqp)
1202 {
1203 int error;
1204 struct kqueue *kq;
1205
1206 error = 0;
1207
1208 kq = fp->f_data;
1209 if (fp->f_type != DTYPE_KQUEUE || kq == NULL)
1210 return (EBADF);
1211 *kqp = kq;
1212 KQ_LOCK(kq);
1213 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
1214 KQ_UNLOCK(kq);
1215 return (EBADF);
1216 }
1217 kq->kq_refcnt++;
1218 KQ_UNLOCK(kq);
1219
1220 return error;
1221 }
1222
1223 static void
1224 kqueue_release(struct kqueue *kq, int locked)
1225 {
1226 if (locked)
1227 KQ_OWNED(kq);
1228 else
1229 KQ_LOCK(kq);
1230 kq->kq_refcnt--;
1231 if (kq->kq_refcnt == 1)
1232 wakeup(&kq->kq_refcnt);
1233 if (!locked)
1234 KQ_UNLOCK(kq);
1235 }
1236
1237 static void
1238 kqueue_schedtask(struct kqueue *kq)
1239 {
1240
1241 KQ_OWNED(kq);
1242 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
1243 ("scheduling kqueue task while draining"));
1244
1245 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
1246 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task);
1247 kq->kq_state |= KQ_TASKSCHED;
1248 }
1249 }
1250
1251 /*
1252 * Expand the kq to make sure we have storage for fops/ident pair.
1253 *
1254 * Return 0 on success (or no work necessary), return errno on failure.
1255 *
1256 * Not calling hashinit w/ waitok (proper malloc flag) should be safe.
1257 * If kqueue_register is called from a non-fd context, there usually/should
1258 * be no locks held.
1259 */
1260 static int
1261 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident,
1262 int waitok)
1263 {
1264 struct klist *list, *tmp_knhash, *to_free;
1265 u_long tmp_knhashmask;
1266 int size;
1267 int fd;
1268 int mflag = waitok ? M_WAITOK : M_NOWAIT;
1269
1270 KQ_NOTOWNED(kq);
1271
1272 to_free = NULL;
1273 if (fops->f_isfd) {
1274 fd = ident;
1275 if (kq->kq_knlistsize <= fd) {
1276 size = kq->kq_knlistsize;
1277 while (size <= fd)
1278 size += KQEXTENT;
1279 list = malloc(size * sizeof(*list), M_KQUEUE, mflag);
1280 if (list == NULL)
1281 return ENOMEM;
1282 KQ_LOCK(kq);
1283 if (kq->kq_knlistsize > fd) {
1284 to_free = list;
1285 list = NULL;
1286 } else {
1287 if (kq->kq_knlist != NULL) {
1288 bcopy(kq->kq_knlist, list,
1289 kq->kq_knlistsize * sizeof(*list));
1290 to_free = kq->kq_knlist;
1291 kq->kq_knlist = NULL;
1292 }
1293 bzero((caddr_t)list +
1294 kq->kq_knlistsize * sizeof(*list),
1295 (size - kq->kq_knlistsize) * sizeof(*list));
1296 kq->kq_knlistsize = size;
1297 kq->kq_knlist = list;
1298 }
1299 KQ_UNLOCK(kq);
1300 }
1301 } else {
1302 if (kq->kq_knhashmask == 0) {
1303 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
1304 &tmp_knhashmask);
1305 if (tmp_knhash == NULL)
1306 return ENOMEM;
1307 KQ_LOCK(kq);
1308 if (kq->kq_knhashmask == 0) {
1309 kq->kq_knhash = tmp_knhash;
1310 kq->kq_knhashmask = tmp_knhashmask;
1311 } else {
1312 to_free = tmp_knhash;
1313 }
1314 KQ_UNLOCK(kq);
1315 }
1316 }
1317 free(to_free, M_KQUEUE);
1318
1319 KQ_NOTOWNED(kq);
1320 return 0;
1321 }
1322
1323 static void
1324 kqueue_task(void *arg, int pending)
1325 {
1326 struct kqueue *kq;
1327 int haskqglobal;
1328
1329 haskqglobal = 0;
1330 kq = arg;
1331
1332 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1333 KQ_LOCK(kq);
1334
1335 KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
1336
1337 kq->kq_state &= ~KQ_TASKSCHED;
1338 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
1339 wakeup(&kq->kq_state);
1340 }
1341 KQ_UNLOCK(kq);
1342 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1343 }
1344
1345 /*
1346 * Scan, update kn_data (if not ONESHOT), and copyout triggered events.
1347 * We treat KN_MARKER knotes as if they are INFLUX.
1348 */
1349 static int
1350 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
1351 const struct timespec *tsp, struct kevent *keva, struct thread *td)
1352 {
1353 struct kevent *kevp;
1354 struct knote *kn, *marker;
1355 sbintime_t asbt, rsbt;
1356 int count, error, haskqglobal, influx, nkev, touch;
1357
1358 count = maxevents;
1359 nkev = 0;
1360 error = 0;
1361 haskqglobal = 0;
1362
1363 if (maxevents == 0)
1364 goto done_nl;
1365
1366 rsbt = 0;
1367 if (tsp != NULL) {
1368 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 ||
1369 tsp->tv_nsec >= 1000000000) {
1370 error = EINVAL;
1371 goto done_nl;
1372 }
1373 if (timespecisset(tsp)) {
1374 if (tsp->tv_sec <= INT32_MAX) {
1375 rsbt = tstosbt(*tsp);
1376 if (TIMESEL(&asbt, rsbt))
1377 asbt += tc_tick_sbt;
1378 if (asbt <= INT64_MAX - rsbt)
1379 asbt += rsbt;
1380 else
1381 asbt = 0;
1382 rsbt >>= tc_precexp;
1383 } else
1384 asbt = 0;
1385 } else
1386 asbt = -1;
1387 } else
1388 asbt = 0;
1389 marker = knote_alloc(1);
1390 if (marker == NULL) {
1391 error = ENOMEM;
1392 goto done_nl;
1393 }
1394 marker->kn_status = KN_MARKER;
1395 KQ_LOCK(kq);
1396
1397 retry:
1398 kevp = keva;
1399 if (kq->kq_count == 0) {
1400 if (asbt == -1) {
1401 error = EWOULDBLOCK;
1402 } else {
1403 kq->kq_state |= KQ_SLEEP;
1404 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH,
1405 "kqread", asbt, rsbt, C_ABSOLUTE);
1406 }
1407 if (error == 0)
1408 goto retry;
1409 /* don't restart after signals... */
1410 if (error == ERESTART)
1411 error = EINTR;
1412 else if (error == EWOULDBLOCK)
1413 error = 0;
1414 goto done;
1415 }
1416
1417 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
1418 influx = 0;
1419 while (count) {
1420 KQ_OWNED(kq);
1421 kn = TAILQ_FIRST(&kq->kq_head);
1422
1423 if ((kn->kn_status == KN_MARKER && kn != marker) ||
1424 (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1425 if (influx) {
1426 influx = 0;
1427 KQ_FLUX_WAKEUP(kq);
1428 }
1429 kq->kq_state |= KQ_FLUXWAIT;
1430 error = msleep(kq, &kq->kq_lock, PSOCK,
1431 "kqflxwt", 0);
1432 continue;
1433 }
1434
1435 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
1436 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
1437 kn->kn_status &= ~KN_QUEUED;
1438 kq->kq_count--;
1439 continue;
1440 }
1441 if (kn == marker) {
1442 KQ_FLUX_WAKEUP(kq);
1443 if (count == maxevents)
1444 goto retry;
1445 goto done;
1446 }
1447 KASSERT((kn->kn_status & KN_INFLUX) == 0,
1448 ("KN_INFLUX set when not suppose to be"));
1449
1450 if ((kn->kn_flags & EV_DROP) == EV_DROP) {
1451 kn->kn_status &= ~KN_QUEUED;
1452 kn->kn_status |= KN_INFLUX;
1453 kq->kq_count--;
1454 KQ_UNLOCK(kq);
1455 /*
1456 * We don't need to lock the list since we've marked
1457 * it _INFLUX.
1458 */
1459 if (!(kn->kn_status & KN_DETACHED))
1460 kn->kn_fop->f_detach(kn);
1461 knote_drop(kn, td);
1462 KQ_LOCK(kq);
1463 continue;
1464 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
1465 kn->kn_status &= ~KN_QUEUED;
1466 kn->kn_status |= KN_INFLUX;
1467 kq->kq_count--;
1468 KQ_UNLOCK(kq);
1469 /*
1470 * We don't need to lock the list since we've marked
1471 * it _INFLUX.
1472 */
1473 *kevp = kn->kn_kevent;
1474 if (!(kn->kn_status & KN_DETACHED))
1475 kn->kn_fop->f_detach(kn);
1476 knote_drop(kn, td);
1477 KQ_LOCK(kq);
1478 kn = NULL;
1479 } else {
1480 kn->kn_status |= KN_INFLUX | KN_SCAN;
1481 KQ_UNLOCK(kq);
1482 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
1483 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1484 KN_LIST_LOCK(kn);
1485 if (kn->kn_fop->f_event(kn, 0) == 0) {
1486 KQ_LOCK(kq);
1487 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1488 kn->kn_status &=
1489 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX |
1490 KN_SCAN);
1491 kq->kq_count--;
1492 KN_LIST_UNLOCK(kn);
1493 influx = 1;
1494 continue;
1495 }
1496 touch = (!kn->kn_fop->f_isfd &&
1497 kn->kn_fop->f_touch != NULL);
1498 if (touch)
1499 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS);
1500 else
1501 *kevp = kn->kn_kevent;
1502 KQ_LOCK(kq);
1503 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1504 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
1505 /*
1506 * Manually clear knotes who weren't
1507 * 'touch'ed.
1508 */
1509 if (touch == 0 && kn->kn_flags & EV_CLEAR) {
1510 kn->kn_data = 0;
1511 kn->kn_fflags = 0;
1512 }
1513 if (kn->kn_flags & EV_DISPATCH)
1514 kn->kn_status |= KN_DISABLED;
1515 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
1516 kq->kq_count--;
1517 } else
1518 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
1519
1520 kn->kn_status &= ~(KN_INFLUX | KN_SCAN);
1521 KN_LIST_UNLOCK(kn);
1522 influx = 1;
1523 }
1524
1525 /* we are returning a copy to the user */
1526 kevp++;
1527 nkev++;
1528 count--;
1529
1530 if (nkev == KQ_NEVENTS) {
1531 influx = 0;
1532 KQ_UNLOCK_FLUX(kq);
1533 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1534 nkev = 0;
1535 kevp = keva;
1536 KQ_LOCK(kq);
1537 if (error)
1538 break;
1539 }
1540 }
1541 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
1542 done:
1543 KQ_OWNED(kq);
1544 KQ_UNLOCK_FLUX(kq);
1545 knote_free(marker);
1546 done_nl:
1547 KQ_NOTOWNED(kq);
1548 if (nkev != 0)
1549 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1550 td->td_retval[0] = maxevents - count;
1551 return (error);
1552 }
1553
1554 /*
1555 * XXX
1556 * This could be expanded to call kqueue_scan, if desired.
1557 */
1558 /*ARGSUSED*/
1559 static int
1560 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
1561 int flags, struct thread *td)
1562 {
1563 return (ENXIO);
1564 }
1565
1566 /*ARGSUSED*/
1567 static int
1568 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
1569 int flags, struct thread *td)
1570 {
1571 return (ENXIO);
1572 }
1573
1574 /*ARGSUSED*/
1575 static int
1576 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred,
1577 struct thread *td)
1578 {
1579
1580 return (EINVAL);
1581 }
1582
1583 /*ARGSUSED*/
1584 static int
1585 kqueue_ioctl(struct file *fp, u_long cmd, void *data,
1586 struct ucred *active_cred, struct thread *td)
1587 {
1588 /*
1589 * Enabling sigio causes two major problems:
1590 * 1) infinite recursion:
1591 * Synopsys: kevent is being used to track signals and have FIOASYNC
1592 * set. On receipt of a signal this will cause a kqueue to recurse
1593 * into itself over and over. Sending the sigio causes the kqueue
1594 * to become ready, which in turn posts sigio again, forever.
1595 * Solution: this can be solved by setting a flag in the kqueue that
1596 * we have a SIGIO in progress.
1597 * 2) locking problems:
1598 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
1599 * us above the proc and pgrp locks.
1600 * Solution: Post a signal using an async mechanism, being sure to
1601 * record a generation count in the delivery so that we do not deliver
1602 * a signal to the wrong process.
1603 *
1604 * Note, these two mechanisms are somewhat mutually exclusive!
1605 */
1606 #if 0
1607 struct kqueue *kq;
1608
1609 kq = fp->f_data;
1610 switch (cmd) {
1611 case FIOASYNC:
1612 if (*(int *)data) {
1613 kq->kq_state |= KQ_ASYNC;
1614 } else {
1615 kq->kq_state &= ~KQ_ASYNC;
1616 }
1617 return (0);
1618
1619 case FIOSETOWN:
1620 return (fsetown(*(int *)data, &kq->kq_sigio));
1621
1622 case FIOGETOWN:
1623 *(int *)data = fgetown(&kq->kq_sigio);
1624 return (0);
1625 }
1626 #endif
1627
1628 return (ENOTTY);
1629 }
1630
1631 /*ARGSUSED*/
1632 static int
1633 kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
1634 struct thread *td)
1635 {
1636 struct kqueue *kq;
1637 int revents = 0;
1638 int error;
1639
1640 if ((error = kqueue_acquire(fp, &kq)))
1641 return POLLERR;
1642
1643 KQ_LOCK(kq);
1644 if (events & (POLLIN | POLLRDNORM)) {
1645 if (kq->kq_count) {
1646 revents |= events & (POLLIN | POLLRDNORM);
1647 } else {
1648 selrecord(td, &kq->kq_sel);
1649 if (SEL_WAITING(&kq->kq_sel))
1650 kq->kq_state |= KQ_SEL;
1651 }
1652 }
1653 kqueue_release(kq, 1);
1654 KQ_UNLOCK(kq);
1655 return (revents);
1656 }
1657
1658 /*ARGSUSED*/
1659 static int
1660 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
1661 struct thread *td)
1662 {
1663
1664 bzero((void *)st, sizeof *st);
1665 /*
1666 * We no longer return kq_count because the unlocked value is useless.
1667 * If you spent all this time getting the count, why not spend your
1668 * syscall better by calling kevent?
1669 *
1670 * XXX - This is needed for libc_r.
1671 */
1672 st->st_mode = S_IFIFO;
1673 return (0);
1674 }
1675
1676 /*ARGSUSED*/
1677 static int
1678 kqueue_close(struct file *fp, struct thread *td)
1679 {
1680 struct kqueue *kq = fp->f_data;
1681 struct filedesc *fdp;
1682 struct knote *kn;
1683 int i;
1684 int error;
1685 int filedesc_unlock;
1686
1687 if ((error = kqueue_acquire(fp, &kq)))
1688 return error;
1689
1690 filedesc_unlock = 0;
1691 KQ_LOCK(kq);
1692
1693 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
1694 ("kqueue already closing"));
1695 kq->kq_state |= KQ_CLOSING;
1696 if (kq->kq_refcnt > 1)
1697 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
1698
1699 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
1700 fdp = kq->kq_fdp;
1701
1702 KASSERT(knlist_empty(&kq->kq_sel.si_note),
1703 ("kqueue's knlist not empty"));
1704
1705 for (i = 0; i < kq->kq_knlistsize; i++) {
1706 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
1707 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1708 kq->kq_state |= KQ_FLUXWAIT;
1709 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
1710 continue;
1711 }
1712 kn->kn_status |= KN_INFLUX;
1713 KQ_UNLOCK(kq);
1714 if (!(kn->kn_status & KN_DETACHED))
1715 kn->kn_fop->f_detach(kn);
1716 knote_drop(kn, td);
1717 KQ_LOCK(kq);
1718 }
1719 }
1720 if (kq->kq_knhashmask != 0) {
1721 for (i = 0; i <= kq->kq_knhashmask; i++) {
1722 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
1723 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1724 kq->kq_state |= KQ_FLUXWAIT;
1725 msleep(kq, &kq->kq_lock, PSOCK,
1726 "kqclo2", 0);
1727 continue;
1728 }
1729 kn->kn_status |= KN_INFLUX;
1730 KQ_UNLOCK(kq);
1731 if (!(kn->kn_status & KN_DETACHED))
1732 kn->kn_fop->f_detach(kn);
1733 knote_drop(kn, td);
1734 KQ_LOCK(kq);
1735 }
1736 }
1737 }
1738
1739 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
1740 kq->kq_state |= KQ_TASKDRAIN;
1741 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
1742 }
1743
1744 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
1745 selwakeuppri(&kq->kq_sel, PSOCK);
1746 if (!SEL_WAITING(&kq->kq_sel))
1747 kq->kq_state &= ~KQ_SEL;
1748 }
1749
1750 KQ_UNLOCK(kq);
1751
1752 /*
1753 * We could be called due to the knote_drop() doing fdrop(),
1754 * called from kqueue_register(). In this case the global
1755 * lock is owned, and filedesc sx is locked before, to not
1756 * take the sleepable lock after non-sleepable.
1757 */
1758 if (!sx_xlocked(FILEDESC_LOCK(fdp))) {
1759 FILEDESC_XLOCK(fdp);
1760 filedesc_unlock = 1;
1761 } else
1762 filedesc_unlock = 0;
1763 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list);
1764 if (filedesc_unlock)
1765 FILEDESC_XUNLOCK(fdp);
1766
1767 seldrain(&kq->kq_sel);
1768 knlist_destroy(&kq->kq_sel.si_note);
1769 mtx_destroy(&kq->kq_lock);
1770 kq->kq_fdp = NULL;
1771
1772 if (kq->kq_knhash != NULL)
1773 free(kq->kq_knhash, M_KQUEUE);
1774 if (kq->kq_knlist != NULL)
1775 free(kq->kq_knlist, M_KQUEUE);
1776
1777 funsetown(&kq->kq_sigio);
1778 free(kq, M_KQUEUE);
1779 fp->f_data = NULL;
1780
1781 return (0);
1782 }
1783
1784 static void
1785 kqueue_wakeup(struct kqueue *kq)
1786 {
1787 KQ_OWNED(kq);
1788
1789 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
1790 kq->kq_state &= ~KQ_SLEEP;
1791 wakeup(kq);
1792 }
1793 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
1794 selwakeuppri(&kq->kq_sel, PSOCK);
1795 if (!SEL_WAITING(&kq->kq_sel))
1796 kq->kq_state &= ~KQ_SEL;
1797 }
1798 if (!knlist_empty(&kq->kq_sel.si_note))
1799 kqueue_schedtask(kq);
1800 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
1801 pgsigio(&kq->kq_sigio, SIGIO, 0);
1802 }
1803 }
1804
1805 /*
1806 * Walk down a list of knotes, activating them if their event has triggered.
1807 *
1808 * There is a possibility to optimize in the case of one kq watching another.
1809 * Instead of scheduling a task to wake it up, you could pass enough state
1810 * down the chain to make up the parent kqueue. Make this code functional
1811 * first.
1812 */
1813 void
1814 knote(struct knlist *list, long hint, int lockflags)
1815 {
1816 struct kqueue *kq;
1817 struct knote *kn;
1818 int error;
1819
1820 if (list == NULL)
1821 return;
1822
1823 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
1824
1825 if ((lockflags & KNF_LISTLOCKED) == 0)
1826 list->kl_lock(list->kl_lockarg);
1827
1828 /*
1829 * If we unlock the list lock (and set KN_INFLUX), we can eliminate
1830 * the kqueue scheduling, but this will introduce four
1831 * lock/unlock's for each knote to test. If we do, continue to use
1832 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is
1833 * only safe if you want to remove the current item, which we are
1834 * not doing.
1835 */
1836 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
1837 kq = kn->kn_kq;
1838 KQ_LOCK(kq);
1839 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) {
1840 /*
1841 * Do not process the influx notes, except for
1842 * the influx coming from the kq unlock in the
1843 * kqueue_scan(). In the later case, we do
1844 * not interfere with the scan, since the code
1845 * fragment in kqueue_scan() locks the knlist,
1846 * and cannot proceed until we finished.
1847 */
1848 KQ_UNLOCK(kq);
1849 } else if ((lockflags & KNF_NOKQLOCK) != 0) {
1850 kn->kn_status |= KN_INFLUX;
1851 KQ_UNLOCK(kq);
1852 error = kn->kn_fop->f_event(kn, hint);
1853 KQ_LOCK(kq);
1854 kn->kn_status &= ~KN_INFLUX;
1855 if (error)
1856 KNOTE_ACTIVATE(kn, 1);
1857 KQ_UNLOCK_FLUX(kq);
1858 } else {
1859 kn->kn_status |= KN_HASKQLOCK;
1860 if (kn->kn_fop->f_event(kn, hint))
1861 KNOTE_ACTIVATE(kn, 1);
1862 kn->kn_status &= ~KN_HASKQLOCK;
1863 KQ_UNLOCK(kq);
1864 }
1865 }
1866 if ((lockflags & KNF_LISTLOCKED) == 0)
1867 list->kl_unlock(list->kl_lockarg);
1868 }
1869
1870 /*
1871 * add a knote to a knlist
1872 */
1873 void
1874 knlist_add(struct knlist *knl, struct knote *kn, int islocked)
1875 {
1876 KNL_ASSERT_LOCK(knl, islocked);
1877 KQ_NOTOWNED(kn->kn_kq);
1878 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) ==
1879 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED"));
1880 if (!islocked)
1881 knl->kl_lock(knl->kl_lockarg);
1882 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext);
1883 if (!islocked)
1884 knl->kl_unlock(knl->kl_lockarg);
1885 KQ_LOCK(kn->kn_kq);
1886 kn->kn_knlist = knl;
1887 kn->kn_status &= ~KN_DETACHED;
1888 KQ_UNLOCK(kn->kn_kq);
1889 }
1890
1891 static void
1892 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked)
1893 {
1894 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked"));
1895 KNL_ASSERT_LOCK(knl, knlislocked);
1896 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED);
1897 if (!kqislocked)
1898 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX,
1899 ("knlist_remove called w/o knote being KN_INFLUX or already removed"));
1900 if (!knlislocked)
1901 knl->kl_lock(knl->kl_lockarg);
1902 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
1903 kn->kn_knlist = NULL;
1904 if (!knlislocked)
1905 knl->kl_unlock(knl->kl_lockarg);
1906 if (!kqislocked)
1907 KQ_LOCK(kn->kn_kq);
1908 kn->kn_status |= KN_DETACHED;
1909 if (!kqislocked)
1910 KQ_UNLOCK(kn->kn_kq);
1911 }
1912
1913 /*
1914 * remove knote from the specified knlist
1915 */
1916 void
1917 knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
1918 {
1919
1920 knlist_remove_kq(knl, kn, islocked, 0);
1921 }
1922
1923 /*
1924 * remove knote from the specified knlist while in f_event handler.
1925 */
1926 void
1927 knlist_remove_inevent(struct knlist *knl, struct knote *kn)
1928 {
1929
1930 knlist_remove_kq(knl, kn, 1,
1931 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK);
1932 }
1933
1934 int
1935 knlist_empty(struct knlist *knl)
1936 {
1937
1938 KNL_ASSERT_LOCKED(knl);
1939 return SLIST_EMPTY(&knl->kl_list);
1940 }
1941
1942 static struct mtx knlist_lock;
1943 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects",
1944 MTX_DEF);
1945 static void knlist_mtx_lock(void *arg);
1946 static void knlist_mtx_unlock(void *arg);
1947
1948 static void
1949 knlist_mtx_lock(void *arg)
1950 {
1951
1952 mtx_lock((struct mtx *)arg);
1953 }
1954
1955 static void
1956 knlist_mtx_unlock(void *arg)
1957 {
1958
1959 mtx_unlock((struct mtx *)arg);
1960 }
1961
1962 static void
1963 knlist_mtx_assert_locked(void *arg)
1964 {
1965
1966 mtx_assert((struct mtx *)arg, MA_OWNED);
1967 }
1968
1969 static void
1970 knlist_mtx_assert_unlocked(void *arg)
1971 {
1972
1973 mtx_assert((struct mtx *)arg, MA_NOTOWNED);
1974 }
1975
1976 static void
1977 knlist_rw_rlock(void *arg)
1978 {
1979
1980 rw_rlock((struct rwlock *)arg);
1981 }
1982
1983 static void
1984 knlist_rw_runlock(void *arg)
1985 {
1986
1987 rw_runlock((struct rwlock *)arg);
1988 }
1989
1990 static void
1991 knlist_rw_assert_locked(void *arg)
1992 {
1993
1994 rw_assert((struct rwlock *)arg, RA_LOCKED);
1995 }
1996
1997 static void
1998 knlist_rw_assert_unlocked(void *arg)
1999 {
2000
2001 rw_assert((struct rwlock *)arg, RA_UNLOCKED);
2002 }
2003
2004 void
2005 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
2006 void (*kl_unlock)(void *),
2007 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *))
2008 {
2009
2010 if (lock == NULL)
2011 knl->kl_lockarg = &knlist_lock;
2012 else
2013 knl->kl_lockarg = lock;
2014
2015 if (kl_lock == NULL)
2016 knl->kl_lock = knlist_mtx_lock;
2017 else
2018 knl->kl_lock = kl_lock;
2019 if (kl_unlock == NULL)
2020 knl->kl_unlock = knlist_mtx_unlock;
2021 else
2022 knl->kl_unlock = kl_unlock;
2023 if (kl_assert_locked == NULL)
2024 knl->kl_assert_locked = knlist_mtx_assert_locked;
2025 else
2026 knl->kl_assert_locked = kl_assert_locked;
2027 if (kl_assert_unlocked == NULL)
2028 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked;
2029 else
2030 knl->kl_assert_unlocked = kl_assert_unlocked;
2031
2032 SLIST_INIT(&knl->kl_list);
2033 }
2034
2035 void
2036 knlist_init_mtx(struct knlist *knl, struct mtx *lock)
2037 {
2038
2039 knlist_init(knl, lock, NULL, NULL, NULL, NULL);
2040 }
2041
2042 void
2043 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock)
2044 {
2045
2046 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock,
2047 knlist_rw_assert_locked, knlist_rw_assert_unlocked);
2048 }
2049
2050 void
2051 knlist_destroy(struct knlist *knl)
2052 {
2053
2054 #ifdef INVARIANTS
2055 /*
2056 * if we run across this error, we need to find the offending
2057 * driver and have it call knlist_clear or knlist_delete.
2058 */
2059 if (!SLIST_EMPTY(&knl->kl_list))
2060 printf("WARNING: destroying knlist w/ knotes on it!\n");
2061 #endif
2062
2063 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL;
2064 SLIST_INIT(&knl->kl_list);
2065 }
2066
2067 /*
2068 * Even if we are locked, we may need to drop the lock to allow any influx
2069 * knotes time to "settle".
2070 */
2071 void
2072 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
2073 {
2074 struct knote *kn, *kn2;
2075 struct kqueue *kq;
2076
2077 if (islocked)
2078 KNL_ASSERT_LOCKED(knl);
2079 else {
2080 KNL_ASSERT_UNLOCKED(knl);
2081 again: /* need to reacquire lock since we have dropped it */
2082 knl->kl_lock(knl->kl_lockarg);
2083 }
2084
2085 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
2086 kq = kn->kn_kq;
2087 KQ_LOCK(kq);
2088 if ((kn->kn_status & KN_INFLUX)) {
2089 KQ_UNLOCK(kq);
2090 continue;
2091 }
2092 knlist_remove_kq(knl, kn, 1, 1);
2093 if (killkn) {
2094 kn->kn_status |= KN_INFLUX | KN_DETACHED;
2095 KQ_UNLOCK(kq);
2096 knote_drop(kn, td);
2097 } else {
2098 /* Make sure cleared knotes disappear soon */
2099 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
2100 KQ_UNLOCK(kq);
2101 }
2102 kq = NULL;
2103 }
2104
2105 if (!SLIST_EMPTY(&knl->kl_list)) {
2106 /* there are still KN_INFLUX remaining */
2107 kn = SLIST_FIRST(&knl->kl_list);
2108 kq = kn->kn_kq;
2109 KQ_LOCK(kq);
2110 KASSERT(kn->kn_status & KN_INFLUX,
2111 ("knote removed w/o list lock"));
2112 knl->kl_unlock(knl->kl_lockarg);
2113 kq->kq_state |= KQ_FLUXWAIT;
2114 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
2115 kq = NULL;
2116 goto again;
2117 }
2118
2119 if (islocked)
2120 KNL_ASSERT_LOCKED(knl);
2121 else {
2122 knl->kl_unlock(knl->kl_lockarg);
2123 KNL_ASSERT_UNLOCKED(knl);
2124 }
2125 }
2126
2127 /*
2128 * Remove all knotes referencing a specified fd must be called with FILEDESC
2129 * lock. This prevents a race where a new fd comes along and occupies the
2130 * entry and we attach a knote to the fd.
2131 */
2132 void
2133 knote_fdclose(struct thread *td, int fd)
2134 {
2135 struct filedesc *fdp = td->td_proc->p_fd;
2136 struct kqueue *kq;
2137 struct knote *kn;
2138 int influx;
2139
2140 FILEDESC_XLOCK_ASSERT(fdp);
2141
2142 /*
2143 * We shouldn't have to worry about new kevents appearing on fd
2144 * since filedesc is locked.
2145 */
2146 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
2147 KQ_LOCK(kq);
2148
2149 again:
2150 influx = 0;
2151 while (kq->kq_knlistsize > fd &&
2152 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
2153 if (kn->kn_status & KN_INFLUX) {
2154 /* someone else might be waiting on our knote */
2155 if (influx)
2156 wakeup(kq);
2157 kq->kq_state |= KQ_FLUXWAIT;
2158 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
2159 goto again;
2160 }
2161 kn->kn_status |= KN_INFLUX;
2162 KQ_UNLOCK(kq);
2163 if (!(kn->kn_status & KN_DETACHED))
2164 kn->kn_fop->f_detach(kn);
2165 knote_drop(kn, td);
2166 influx = 1;
2167 KQ_LOCK(kq);
2168 }
2169 KQ_UNLOCK_FLUX(kq);
2170 }
2171 }
2172
2173 static int
2174 knote_attach(struct knote *kn, struct kqueue *kq)
2175 {
2176 struct klist *list;
2177
2178 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX"));
2179 KQ_OWNED(kq);
2180
2181 if (kn->kn_fop->f_isfd) {
2182 if (kn->kn_id >= kq->kq_knlistsize)
2183 return ENOMEM;
2184 list = &kq->kq_knlist[kn->kn_id];
2185 } else {
2186 if (kq->kq_knhash == NULL)
2187 return ENOMEM;
2188 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2189 }
2190
2191 SLIST_INSERT_HEAD(list, kn, kn_link);
2192
2193 return 0;
2194 }
2195
2196 /*
2197 * knote must already have been detached using the f_detach method.
2198 * no lock need to be held, it is assumed that the KN_INFLUX flag is set
2199 * to prevent other removal.
2200 */
2201 static void
2202 knote_drop(struct knote *kn, struct thread *td)
2203 {
2204 struct kqueue *kq;
2205 struct klist *list;
2206
2207 kq = kn->kn_kq;
2208
2209 KQ_NOTOWNED(kq);
2210 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX,
2211 ("knote_drop called without KN_INFLUX set in kn_status"));
2212
2213 KQ_LOCK(kq);
2214 if (kn->kn_fop->f_isfd)
2215 list = &kq->kq_knlist[kn->kn_id];
2216 else
2217 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2218
2219 if (!SLIST_EMPTY(list))
2220 SLIST_REMOVE(list, kn, knote, kn_link);
2221 if (kn->kn_status & KN_QUEUED)
2222 knote_dequeue(kn);
2223 KQ_UNLOCK_FLUX(kq);
2224
2225 if (kn->kn_fop->f_isfd) {
2226 fdrop(kn->kn_fp, td);
2227 kn->kn_fp = NULL;
2228 }
2229 kqueue_fo_release(kn->kn_kevent.filter);
2230 kn->kn_fop = NULL;
2231 knote_free(kn);
2232 }
2233
2234 static void
2235 knote_enqueue(struct knote *kn)
2236 {
2237 struct kqueue *kq = kn->kn_kq;
2238
2239 KQ_OWNED(kn->kn_kq);
2240 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
2241
2242 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
2243 kn->kn_status |= KN_QUEUED;
2244 kq->kq_count++;
2245 kqueue_wakeup(kq);
2246 }
2247
2248 static void
2249 knote_dequeue(struct knote *kn)
2250 {
2251 struct kqueue *kq = kn->kn_kq;
2252
2253 KQ_OWNED(kn->kn_kq);
2254 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
2255
2256 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
2257 kn->kn_status &= ~KN_QUEUED;
2258 kq->kq_count--;
2259 }
2260
2261 static void
2262 knote_init(void)
2263 {
2264
2265 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
2266 NULL, NULL, UMA_ALIGN_PTR, 0);
2267 }
2268 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
2269
2270 static struct knote *
2271 knote_alloc(int waitok)
2272 {
2273 return ((struct knote *)uma_zalloc(knote_zone,
2274 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO));
2275 }
2276
2277 static void
2278 knote_free(struct knote *kn)
2279 {
2280 if (kn != NULL)
2281 uma_zfree(knote_zone, kn);
2282 }
2283
2284 /*
2285 * Register the kev w/ the kq specified by fd.
2286 */
2287 int
2288 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok)
2289 {
2290 struct kqueue *kq;
2291 struct file *fp;
2292 cap_rights_t rights;
2293 int error;
2294
2295 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp);
2296 if (error != 0)
2297 return (error);
2298 if ((error = kqueue_acquire(fp, &kq)) != 0)
2299 goto noacquire;
2300
2301 error = kqueue_register(kq, kev, td, waitok);
2302
2303 kqueue_release(kq, 0);
2304
2305 noacquire:
2306 fdrop(fp, td);
2307
2308 return error;
2309 }
Cache object: 30643b9d584b8d853af788996dee62a0
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