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kernel: Remove kernel profiling bits.
[dragonfly.git] / sys / kern / kern_event.c
blob069eeda97157604b75a5d0634c0401b5c1b02176
1 /*-
2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: src/sys/kern/kern_event.c,v 1.2.2.10 2004/04/04 07:03:14 cperciva Exp $
27 */
28
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/kernel.h>
32 #include <sys/proc.h>
33 #include <sys/malloc.h>
34 #include <sys/unistd.h>
35 #include <sys/file.h>
36 #include <sys/lock.h>
37 #include <sys/fcntl.h>
38 #include <sys/queue.h>
39 #include <sys/event.h>
40 #include <sys/eventvar.h>
41 #include <sys/protosw.h>
42 #include <sys/socket.h>
43 #include <sys/socketvar.h>
44 #include <sys/stat.h>
45 #include <sys/sysctl.h>
46 #include <sys/sysproto.h>
47 #include <sys/thread.h>
48 #include <sys/uio.h>
49 #include <sys/signalvar.h>
50 #include <sys/filio.h>
51 #include <sys/ktr.h>
52 #include <sys/spinlock.h>
53
54 #include <sys/thread2.h>
55 #include <sys/file2.h>
56 #include <sys/mplock2.h>
57 #include <sys/spinlock2.h>
58
59 #define EVENT_REGISTER 1
60 #define EVENT_PROCESS 2
61
62 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
63
64 struct kevent_copyin_args {
65 struct kevent_args *ka;
66 int pchanges;
67 };
68
69 #define KNOTE_CACHE_MAX 8
70
71 struct knote_cache_list {
72 struct klist knote_cache;
73 int knote_cache_cnt;
74 } __cachealign;
75
76 static int kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count,
77 struct knote *marker, int closedcounter);
78 static int kqueue_read(struct file *fp, struct uio *uio,
79 struct ucred *cred, int flags);
80 static int kqueue_write(struct file *fp, struct uio *uio,
81 struct ucred *cred, int flags);
82 static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
83 struct ucred *cred, struct sysmsg *msg);
84 static int kqueue_kqfilter(struct file *fp, struct knote *kn);
85 static int kqueue_stat(struct file *fp, struct stat *st,
86 struct ucred *cred);
87 static int kqueue_close(struct file *fp);
88 static void kqueue_wakeup(struct kqueue *kq);
89 static int filter_attach(struct knote *kn);
90 static int filter_event(struct knote *kn, long hint);
91
92 /*
93 * MPSAFE
94 */
95 static struct fileops kqueueops = {
96 .fo_read = kqueue_read,
97 .fo_write = kqueue_write,
98 .fo_ioctl = kqueue_ioctl,
99 .fo_kqfilter = kqueue_kqfilter,
100 .fo_stat = kqueue_stat,
101 .fo_close = kqueue_close,
102 .fo_shutdown = nofo_shutdown
103 };
104
105 static void knote_attach(struct knote *kn);
106 static void knote_drop(struct knote *kn);
107 static void knote_detach_and_drop(struct knote *kn);
108 static void knote_enqueue(struct knote *kn);
109 static void knote_dequeue(struct knote *kn);
110 static struct knote *knote_alloc(void);
111 static void knote_free(struct knote *kn);
112
113 static void precise_sleep_intr(systimer_t info, int in_ipi,
114 struct intrframe *frame);
115 static int precise_sleep(void *ident, int flags, const char *wmesg,
116 int us);
117
118 static void filt_kqdetach(struct knote *kn);
119 static int filt_kqueue(struct knote *kn, long hint);
120 static int filt_procattach(struct knote *kn);
121 static void filt_procdetach(struct knote *kn);
122 static int filt_proc(struct knote *kn, long hint);
123 static int filt_fileattach(struct knote *kn);
124 static void filt_timerexpire(void *knx);
125 static int filt_timerattach(struct knote *kn);
126 static void filt_timerdetach(struct knote *kn);
127 static int filt_timer(struct knote *kn, long hint);
128 static int filt_userattach(struct knote *kn);
129 static void filt_userdetach(struct knote *kn);
130 static int filt_user(struct knote *kn, long hint);
131 static void filt_usertouch(struct knote *kn, struct kevent *kev,
132 u_long type);
133 static int filt_fsattach(struct knote *kn);
134 static void filt_fsdetach(struct knote *kn);
135 static int filt_fs(struct knote *kn, long hint);
136
137 static struct filterops file_filtops =
138 { FILTEROP_ISFD | FILTEROP_MPSAFE, filt_fileattach, NULL, NULL };
139 static struct filterops kqread_filtops =
140 { FILTEROP_ISFD | FILTEROP_MPSAFE, NULL, filt_kqdetach, filt_kqueue };
141 static struct filterops proc_filtops =
142 { FILTEROP_MPSAFE, filt_procattach, filt_procdetach, filt_proc };
143 static struct filterops timer_filtops =
144 { FILTEROP_MPSAFE, filt_timerattach, filt_timerdetach, filt_timer };
145 static struct filterops user_filtops =
146 { FILTEROP_MPSAFE, filt_userattach, filt_userdetach, filt_user };
147 static struct filterops fs_filtops =
148 { FILTEROP_MPSAFE, filt_fsattach, filt_fsdetach, filt_fs };
149
150 static int kq_ncallouts = 0;
151 static int kq_calloutmax = 65536;
152 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
153 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
154 static int kq_checkloop = 1000000;
155 SYSCTL_INT(_kern, OID_AUTO, kq_checkloop, CTLFLAG_RW,
156 &kq_checkloop, 0, "Maximum number of loops for kqueue scan");
157 static int kq_sleep_threshold = 20000;
158 SYSCTL_INT(_kern, OID_AUTO, kq_sleep_threshold, CTLFLAG_RW,
159 &kq_sleep_threshold, 0, "Minimum sleep duration without busy-looping");
160
161 #define KNOTE_ACTIVATE(kn) do { \
162 kn->kn_status |= KN_ACTIVE; \
163 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
164 knote_enqueue(kn); \
165 } while(0)
166
167 #define KN_HASHSIZE 64 /* XXX should be tunable */
168 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
169
170 extern struct filterops aio_filtops;
171 extern struct filterops sig_filtops;
172
173 /*
174 * Table for for all system-defined filters.
175 */
176 static struct filterops *sysfilt_ops[] = {
177 &file_filtops, /* EVFILT_READ */
178 &file_filtops, /* EVFILT_WRITE */
179 &aio_filtops, /* EVFILT_AIO */
180 &file_filtops, /* EVFILT_VNODE */
181 &proc_filtops, /* EVFILT_PROC */
182 &sig_filtops, /* EVFILT_SIGNAL */
183 &timer_filtops, /* EVFILT_TIMER */
184 &file_filtops, /* EVFILT_EXCEPT */
185 &user_filtops, /* EVFILT_USER */
186 &fs_filtops, /* EVFILT_FS */
187 };
188
189 static struct knote_cache_list knote_cache_lists[MAXCPU];
190
191 /*
192 * Acquire a knote, return non-zero on success, 0 on failure.
193 *
194 * If we cannot acquire the knote we sleep and return 0. The knote
195 * may be stale on return in this case and the caller must restart
196 * whatever loop they are in.
197 *
198 * Related kq token must be held.
199 */
200 static __inline int
201 knote_acquire(struct knote *kn)
202 {
203 if (kn->kn_status & KN_PROCESSING) {
204 kn->kn_status |= KN_WAITING | KN_REPROCESS;
205 tsleep(kn, 0, "kqepts", hz);
206 /* knote may be stale now */
207 return(0);
208 }
209 kn->kn_status |= KN_PROCESSING;
210 return(1);
211 }
212
213 /*
214 * Release an acquired knote, clearing KN_PROCESSING and handling any
215 * KN_REPROCESS events.
216 *
217 * Caller must be holding the related kq token
218 *
219 * Non-zero is returned if the knote is destroyed or detached.
220 */
221 static __inline int
222 knote_release(struct knote *kn)
223 {
224 int ret;
225
226 while (kn->kn_status & KN_REPROCESS) {
227 kn->kn_status &= ~KN_REPROCESS;
228 if (kn->kn_status & KN_WAITING) {
229 kn->kn_status &= ~KN_WAITING;
230 wakeup(kn);
231 }
232 if (kn->kn_status & KN_DELETING) {
233 knote_detach_and_drop(kn);
234 return(1);
235 /* NOT REACHED */
236 }
237 if (filter_event(kn, 0))
238 KNOTE_ACTIVATE(kn);
239 }
240 if (kn->kn_status & KN_DETACHED)
241 ret = 1;
242 else
243 ret = 0;
244 kn->kn_status &= ~KN_PROCESSING;
245 /* kn should not be accessed anymore */
246 return ret;
247 }
248
249 static int
250 filt_fileattach(struct knote *kn)
251 {
252 return (fo_kqfilter(kn->kn_fp, kn));
253 }
254
255 /*
256 * MPSAFE
257 */
258 static int
259 kqueue_kqfilter(struct file *fp, struct knote *kn)
260 {
261 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
262
263 if (kn->kn_filter != EVFILT_READ)
264 return (EOPNOTSUPP);
265
266 kn->kn_fop = &kqread_filtops;
267 knote_insert(&kq->kq_kqinfo.ki_note, kn);
268 return (0);
269 }
270
271 static void
272 filt_kqdetach(struct knote *kn)
273 {
274 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
275
276 knote_remove(&kq->kq_kqinfo.ki_note, kn);
277 }
278
279 /*ARGSUSED*/
280 static int
281 filt_kqueue(struct knote *kn, long hint)
282 {
283 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
284
285 kn->kn_data = kq->kq_count;
286 return (kn->kn_data > 0);
287 }
288
289 static int
290 filt_procattach(struct knote *kn)
291 {
292 struct proc *p;
293 int immediate;
294
295 immediate = 0;
296 p = pfind(kn->kn_id);
297 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
298 p = zpfind(kn->kn_id);
299 immediate = 1;
300 }
301 if (p == NULL) {
302 return (ESRCH);
303 }
304 if (!PRISON_CHECK(curthread->td_ucred, p->p_ucred)) {
305 if (p)
306 PRELE(p);
307 return (EACCES);
308 }
309
310 lwkt_gettoken(&p->p_token);
311 kn->kn_ptr.p_proc = p;
312 kn->kn_flags |= EV_CLEAR; /* automatically set */
313
314 /*
315 * internal flag indicating registration done by kernel
316 */
317 if (kn->kn_flags & EV_FLAG1) {
318 kn->kn_data = kn->kn_sdata; /* ppid */
319 kn->kn_fflags = NOTE_CHILD;
320 kn->kn_flags &= ~EV_FLAG1;
321 }
322
323 knote_insert(&p->p_klist, kn);
324
325 /*
326 * Immediately activate any exit notes if the target process is a
327 * zombie. This is necessary to handle the case where the target
328 * process, e.g. a child, dies before the kevent is negistered.
329 */
330 if (immediate && filt_proc(kn, NOTE_EXIT))
331 KNOTE_ACTIVATE(kn);
332 lwkt_reltoken(&p->p_token);
333 PRELE(p);
334
335 return (0);
336 }
337
338 /*
339 * The knote may be attached to a different process, which may exit,
340 * leaving nothing for the knote to be attached to. So when the process
341 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
342 * it will be deleted when read out. However, as part of the knote deletion,
343 * this routine is called, so a check is needed to avoid actually performing
344 * a detach, because the original process does not exist any more.
345 */
346 static void
347 filt_procdetach(struct knote *kn)
348 {
349 struct proc *p;
350
351 if (kn->kn_status & KN_DETACHED)
352 return;
353 p = kn->kn_ptr.p_proc;
354 knote_remove(&p->p_klist, kn);
355 }
356
357 static int
358 filt_proc(struct knote *kn, long hint)
359 {
360 u_int event;
361
362 /*
363 * mask off extra data
364 */
365 event = (u_int)hint & NOTE_PCTRLMASK;
366
367 /*
368 * if the user is interested in this event, record it.
369 */
370 if (kn->kn_sfflags & event)
371 kn->kn_fflags |= event;
372
373 /*
374 * Process is gone, so flag the event as finished. Detach the
375 * knote from the process now because the process will be poof,
376 * gone later on.
377 */
378 if (event == NOTE_EXIT) {
379 struct proc *p = kn->kn_ptr.p_proc;
380 if ((kn->kn_status & KN_DETACHED) == 0) {
381 PHOLD(p);
382 knote_remove(&p->p_klist, kn);
383 kn->kn_status |= KN_DETACHED;
384 kn->kn_data = p->p_xstat;
385 kn->kn_ptr.p_proc = NULL;
386 PRELE(p);
387 }
388 kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT);
389 return (1);
390 }
391
392 /*
393 * process forked, and user wants to track the new process,
394 * so attach a new knote to it, and immediately report an
395 * event with the parent's pid.
396 */
397 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
398 struct kevent kev;
399 int error;
400 int n;
401
402 /*
403 * register knote with new process.
404 */
405 kev.ident = hint & NOTE_PDATAMASK; /* pid */
406 kev.filter = kn->kn_filter;
407 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
408 kev.fflags = kn->kn_sfflags;
409 kev.data = kn->kn_id; /* parent */
410 kev.udata = kn->kn_kevent.udata; /* preserve udata */
411 n = 1;
412 error = kqueue_register(kn->kn_kq, &kev, &n);
413 if (error)
414 kn->kn_fflags |= NOTE_TRACKERR;
415 }
416
417 return (kn->kn_fflags != 0);
418 }
419
420 static void
421 filt_timerreset(struct knote *kn)
422 {
423 struct callout *calloutp;
424 struct timeval tv;
425 int tticks;
426
427 tv.tv_sec = kn->kn_sdata / 1000;
428 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
429 tticks = tvtohz_high(&tv);
430 calloutp = (struct callout *)kn->kn_hook;
431 callout_reset(calloutp, tticks, filt_timerexpire, kn);
432 }
433
434 /*
435 * The callout interlocks with callout_stop() but can still
436 * race a deletion so if KN_DELETING is set we just don't touch
437 * the knote.
438 */
439 static void
440 filt_timerexpire(void *knx)
441 {
442 struct knote *kn = knx;
443 struct kqueue *kq = kn->kn_kq;
444
445 lwkt_getpooltoken(kq);
446
447 /*
448 * Open knote_acquire(), since we can't sleep in callout,
449 * however, we do need to record this expiration.
450 */
451 kn->kn_data++;
452 if (kn->kn_status & KN_PROCESSING) {
453 kn->kn_status |= KN_REPROCESS;
454 if ((kn->kn_status & KN_DELETING) == 0 &&
455 (kn->kn_flags & EV_ONESHOT) == 0)
456 filt_timerreset(kn);
457 lwkt_relpooltoken(kq);
458 return;
459 }
460 KASSERT((kn->kn_status & KN_DELETING) == 0,
461 ("acquire a deleting knote %#x", kn->kn_status));
462 kn->kn_status |= KN_PROCESSING;
463
464 KNOTE_ACTIVATE(kn);
465 if ((kn->kn_flags & EV_ONESHOT) == 0)
466 filt_timerreset(kn);
467
468 knote_release(kn);
469
470 lwkt_relpooltoken(kq);
471 }
472
473 /*
474 * data contains amount of time to sleep, in milliseconds
475 */
476 static int
477 filt_timerattach(struct knote *kn)
478 {
479 struct callout *calloutp;
480 int prev_ncallouts;
481
482 prev_ncallouts = atomic_fetchadd_int(&kq_ncallouts, 1);
483 if (prev_ncallouts >= kq_calloutmax) {
484 atomic_subtract_int(&kq_ncallouts, 1);
485 kn->kn_hook = NULL;
486 return (ENOMEM);
487 }
488
489 kn->kn_flags |= EV_CLEAR; /* automatically set */
490 calloutp = kmalloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK);
491 callout_init_mp(calloutp);
492 kn->kn_hook = (caddr_t)calloutp;
493
494 filt_timerreset(kn);
495 return (0);
496 }
497
498 /*
499 * This function is called with the knote flagged locked but it is
500 * still possible to race a callout event due to the callback blocking.
501 *
502 * NOTE: Even though the note is locked via KN_PROCSESING, filt_timerexpire()
503 * can still race us requeue the callout due to potential token cycling
504 * from various blocking conditions. If this situation arises,
505 * callout_stop_sync() will always return non-zero and we can simply
506 * retry the operation.
507 */
508 static void
509 filt_timerdetach(struct knote *kn)
510 {
511 struct callout *calloutp;
512
513 calloutp = (struct callout *)kn->kn_hook;
514 while (callout_stop_sync(calloutp)) {
515 kprintf("debug: kqueue timer race fixed, pid %d %s\n",
516 (curthread->td_proc ? curthread->td_proc->p_pid : 0),
517 curthread->td_comm);
518 }
519 kn->kn_hook = NULL;
520 kfree(calloutp, M_KQUEUE);
521 atomic_subtract_int(&kq_ncallouts, 1);
522 }
523
524 static int
525 filt_timer(struct knote *kn, long hint)
526 {
527 return (kn->kn_data != 0);
528 }
529
530 /*
531 * EVFILT_USER
532 */
533 static int
534 filt_userattach(struct knote *kn)
535 {
536 u_int ffctrl;
537
538 kn->kn_hook = NULL;
539 if (kn->kn_sfflags & NOTE_TRIGGER)
540 kn->kn_ptr.hookid = 1;
541 else
542 kn->kn_ptr.hookid = 0;
543
544 ffctrl = kn->kn_sfflags & NOTE_FFCTRLMASK;
545 kn->kn_sfflags &= NOTE_FFLAGSMASK;
546 switch (ffctrl) {
547 case NOTE_FFNOP:
548 break;
549
550 case NOTE_FFAND:
551 kn->kn_fflags &= kn->kn_sfflags;
552 break;
553
554 case NOTE_FFOR:
555 kn->kn_fflags |= kn->kn_sfflags;
556 break;
557
558 case NOTE_FFCOPY:
559 kn->kn_fflags = kn->kn_sfflags;
560 break;
561
562 default:
563 /* XXX Return error? */
564 break;
565 }
566 /* We just happen to copy this value as well. Undocumented. */
567 kn->kn_data = kn->kn_sdata;
568
569 return 0;
570 }
571
572 static void
573 filt_userdetach(struct knote *kn)
574 {
575 /* nothing to do */
576 }
577
578 static int
579 filt_user(struct knote *kn, long hint)
580 {
581 return (kn->kn_ptr.hookid);
582 }
583
584 static void
585 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
586 {
587 u_int ffctrl;
588
589 switch (type) {
590 case EVENT_REGISTER:
591 if (kev->fflags & NOTE_TRIGGER)
592 kn->kn_ptr.hookid = 1;
593
594 ffctrl = kev->fflags & NOTE_FFCTRLMASK;
595 kev->fflags &= NOTE_FFLAGSMASK;
596 switch (ffctrl) {
597 case NOTE_FFNOP:
598 break;
599
600 case NOTE_FFAND:
601 kn->kn_fflags &= kev->fflags;
602 break;
603
604 case NOTE_FFOR:
605 kn->kn_fflags |= kev->fflags;
606 break;
607
608 case NOTE_FFCOPY:
609 kn->kn_fflags = kev->fflags;
610 break;
611
612 default:
613 /* XXX Return error? */
614 break;
615 }
616 /* We just happen to copy this value as well. Undocumented. */
617 kn->kn_data = kev->data;
618
619 /*
620 * This is not the correct use of EV_CLEAR in an event
621 * modification, it should have been passed as a NOTE instead.
622 * But we need to maintain compatibility with Apple & FreeBSD.
623 *
624 * Note however that EV_CLEAR can still be used when doing
625 * the initial registration of the event and works as expected
626 * (clears the event on reception).
627 */
628 if (kev->flags & EV_CLEAR) {
629 kn->kn_ptr.hookid = 0;
630 /*
631 * Clearing kn->kn_data is fine, since it gets set
632 * every time anyway. We just shouldn't clear
633 * kn->kn_fflags here, since that would limit the
634 * possible uses of this API. NOTE_FFAND or
635 * NOTE_FFCOPY should be used for explicitly clearing
636 * kn->kn_fflags.
637 */
638 kn->kn_data = 0;
639 }
640 break;
641
642 case EVENT_PROCESS:
643 *kev = kn->kn_kevent;
644 kev->fflags = kn->kn_fflags;
645 kev->data = kn->kn_data;
646 if (kn->kn_flags & EV_CLEAR) {
647 kn->kn_ptr.hookid = 0;
648 /* kn_data, kn_fflags handled by parent */
649 }
650 break;
651
652 default:
653 panic("filt_usertouch() - invalid type (%ld)", type);
654 break;
655 }
656 }
657
658 /*
659 * EVFILT_FS
660 */
661 struct klist fs_klist = SLIST_HEAD_INITIALIZER(&fs_klist);
662
663 static int
664 filt_fsattach(struct knote *kn)
665 {
666 kn->kn_flags |= EV_CLEAR;
667 knote_insert(&fs_klist, kn);
668
669 return (0);
670 }
671
672 static void
673 filt_fsdetach(struct knote *kn)
674 {
675 knote_remove(&fs_klist, kn);
676 }
677
678 static int
679 filt_fs(struct knote *kn, long hint)
680 {
681 kn->kn_fflags |= hint;
682 return (kn->kn_fflags != 0);
683 }
684
685 /*
686 * Initialize a kqueue.
687 *
688 * NOTE: The lwp/proc code initializes a kqueue for select/poll ops.
689 *
690 * MPSAFE
691 */
692 void
693 kqueue_init(struct kqueue *kq, struct filedesc *fdp)
694 {
695 TAILQ_INIT(&kq->kq_knpend);
696 TAILQ_INIT(&kq->kq_knlist);
697 kq->kq_count = 0;
698 kq->kq_fdp = fdp;
699 SLIST_INIT(&kq->kq_kqinfo.ki_note);
700 }
701
702 /*
703 * Terminate a kqueue. Freeing the actual kq itself is left up to the
704 * caller (it might be embedded in a lwp so we don't do it here).
705 *
706 * The kq's knlist must be completely eradicated so block on any
707 * processing races.
708 */
709 void
710 kqueue_terminate(struct kqueue *kq)
711 {
712 struct knote *kn;
713
714 lwkt_getpooltoken(kq);
715 while ((kn = TAILQ_FIRST(&kq->kq_knlist)) != NULL) {
716 if (knote_acquire(kn))
717 knote_detach_and_drop(kn);
718 }
719 lwkt_relpooltoken(kq);
720
721 if (kq->kq_knhash) {
722 hashdestroy(kq->kq_knhash, M_KQUEUE, kq->kq_knhashmask);
723 kq->kq_knhash = NULL;
724 kq->kq_knhashmask = 0;
725 }
726 }
727
728 /*
729 * MPSAFE
730 */
731 int
732 sys_kqueue(struct kqueue_args *uap)
733 {
734 struct thread *td = curthread;
735 struct kqueue *kq;
736 struct file *fp;
737 int fd, error;
738
739 error = falloc(td->td_lwp, &fp, &fd);
740 if (error)
741 return (error);
742 fp->f_flag = FREAD | FWRITE;
743 fp->f_type = DTYPE_KQUEUE;
744 fp->f_ops = &kqueueops;
745
746 kq = kmalloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO);
747 kqueue_init(kq, td->td_proc->p_fd);
748 fp->f_data = kq;
749
750 fsetfd(kq->kq_fdp, fp, fd);
751 uap->sysmsg_result = fd;
752 fdrop(fp);
753 return (error);
754 }
755
756 /*
757 * Copy 'count' items into the destination list pointed to by uap->eventlist.
758 */
759 static int
760 kevent_copyout(void *arg, struct kevent *kevp, int count, int *res)
761 {
762 struct kevent_copyin_args *kap;
763 int error;
764
765 kap = (struct kevent_copyin_args *)arg;
766
767 error = copyout(kevp, kap->ka->eventlist, count * sizeof(*kevp));
768 if (error == 0) {
769 kap->ka->eventlist += count;
770 *res += count;
771 } else {
772 *res = -1;
773 }
774
775 return (error);
776 }
777
778 /*
779 * Copy at most 'max' items from the list pointed to by kap->changelist,
780 * return number of items in 'events'.
781 */
782 static int
783 kevent_copyin(void *arg, struct kevent *kevp, int max, int *events)
784 {
785 struct kevent_copyin_args *kap;
786 int error, count;
787
788 kap = (struct kevent_copyin_args *)arg;
789
790 count = min(kap->ka->nchanges - kap->pchanges, max);
791 error = copyin(kap->ka->changelist, kevp, count * sizeof *kevp);
792 if (error == 0) {
793 kap->ka->changelist += count;
794 kap->pchanges += count;
795 *events = count;
796 }
797
798 return (error);
799 }
800
801 /*
802 * MPSAFE
803 */
804 int
805 kern_kevent(struct kqueue *kq, int nevents, int *res, void *uap,
806 k_copyin_fn kevent_copyinfn, k_copyout_fn kevent_copyoutfn,
807 struct timespec *tsp_in, int flags)
808 {
809 struct kevent *kevp;
810 struct timespec *tsp, ats;
811 int i, n, total, error, nerrors = 0;
812 int gobbled;
813 int lres;
814 int limit = kq_checkloop;
815 int closedcounter;
816 struct kevent kev[KQ_NEVENTS];
817 struct knote marker;
818 struct lwkt_token *tok;
819
820 if (tsp_in == NULL || tsp_in->tv_sec || tsp_in->tv_nsec)
821 atomic_set_int(&curthread->td_mpflags, TDF_MP_BATCH_DEMARC);
822
823 tsp = tsp_in;
824 *res = 0;
825
826 closedcounter = kq->kq_fdp->fd_closedcounter;
827
828 for (;;) {
829 n = 0;
830 error = kevent_copyinfn(uap, kev, KQ_NEVENTS, &n);
831 if (error)
832 return error;
833 if (n == 0)
834 break;
835 for (i = 0; i < n; ++i)
836 kev[i].flags &= ~EV_SYSFLAGS;
837 for (i = 0; i < n; ++i) {
838 gobbled = n - i;
839 error = kqueue_register(kq, &kev[i], &gobbled);
840 i += gobbled - 1;
841 kevp = &kev[i];
842
843 /*
844 * If a registration returns an error we
845 * immediately post the error. The kevent()
846 * call itself will fail with the error if
847 * no space is available for posting.
848 *
849 * Such errors normally bypass the timeout/blocking
850 * code. However, if the copyoutfn function refuses
851 * to post the error (see sys_poll()), then we
852 * ignore it too.
853 */
854 if (error || (kevp->flags & EV_RECEIPT)) {
855 kevp->flags = EV_ERROR;
856 kevp->data = error;
857 lres = *res;
858 kevent_copyoutfn(uap, kevp, 1, res);
859 if (*res < 0) {
860 return error;
861 } else if (lres != *res) {
862 nevents--;
863 nerrors++;
864 }
865 }
866 }
867 }
868 if (nerrors)
869 return 0;
870
871 /*
872 * Acquire/wait for events - setup timeout
873 */
874 if (tsp != NULL) {
875 if (tsp->tv_sec || tsp->tv_nsec) {
876 getnanouptime(&ats);
877 timespecadd(tsp, &ats); /* tsp = target time */
878 }
879 }
880
881 /*
882 * Loop as required.
883 *
884 * Collect as many events as we can. Sleeping on successive
885 * loops is disabled if copyoutfn has incremented (*res).
886 *
887 * The loop stops if an error occurs, all events have been
888 * scanned (the marker has been reached), or fewer than the
889 * maximum number of events is found.
890 *
891 * The copyoutfn function does not have to increment (*res) in
892 * order for the loop to continue.
893 *
894 * NOTE: doselect() usually passes 0x7FFFFFFF for nevents.
895 */
896 total = 0;
897 error = 0;
898 marker.kn_filter = EVFILT_MARKER;
899 marker.kn_status = KN_PROCESSING;
900 tok = lwkt_token_pool_lookup(kq);
901 lwkt_gettoken(tok);
902 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe);
903 lwkt_reltoken(tok);
904 while ((n = nevents - total) > 0) {
905 if (n > KQ_NEVENTS)
906 n = KQ_NEVENTS;
907
908 /*
909 * If no events are pending sleep until timeout (if any)
910 * or an event occurs.
911 *
912 * After the sleep completes the marker is moved to the
913 * end of the list, making any received events available
914 * to our scan.
915 */
916 if (kq->kq_count == 0 && *res == 0) {
917 int timeout, ustimeout = 0;
918
919 if (tsp == NULL) {
920 timeout = 0;
921 } else if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) {
922 error = EWOULDBLOCK;
923 break;
924 } else {
925 struct timespec atx = *tsp;
926
927 getnanouptime(&ats);
928 timespecsub(&atx, &ats);
929 if (atx.tv_sec < 0) {
930 error = EWOULDBLOCK;
931 break;
932 } else {
933 timeout = atx.tv_sec > 24 * 60 * 60 ?
934 24 * 60 * 60 * hz :
935 tstohz_high(&atx);
936 }
937 if (flags & KEVENT_TIMEOUT_PRECISE &&
938 timeout != 0) {
939 if (atx.tv_sec == 0 &&
940 atx.tv_nsec < kq_sleep_threshold) {
941 DELAY(atx.tv_nsec / 1000);
942 error = EWOULDBLOCK;
943 break;
944 } else if (atx.tv_sec < 2000) {
945 ustimeout = atx.tv_sec *
946 1000000 + atx.tv_nsec/1000;
947 } else {
948 ustimeout = 2000000000;
949 }
950 }
951 }
952
953 lwkt_gettoken(tok);
954 if (kq->kq_count == 0) {
955 kq->kq_sleep_cnt++;
956 if (__predict_false(kq->kq_sleep_cnt == 0)) {
957 /*
958 * Guard against possible wrapping. And
959 * set it to 2, so that kqueue_wakeup()
960 * can wake everyone up.
961 */
962 kq->kq_sleep_cnt = 2;
963 }
964 if ((flags & KEVENT_TIMEOUT_PRECISE) &&
965 timeout != 0) {
966 error = precise_sleep(kq, PCATCH,
967 "kqread", ustimeout);
968 } else {
969 error = tsleep(kq, PCATCH, "kqread",
970 timeout);
971 }
972
973 /* don't restart after signals... */
974 if (error == ERESTART)
975 error = EINTR;
976 if (error) {
977 lwkt_reltoken(tok);
978 break;
979 }
980
981 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe);
982 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker,
983 kn_tqe);
984 }
985 lwkt_reltoken(tok);
986 }
987
988 /*
989 * Process all received events
990 * Account for all non-spurious events in our total
991 */
992 i = kqueue_scan(kq, kev, n, &marker, closedcounter);
993 if (i) {
994 lres = *res;
995 error = kevent_copyoutfn(uap, kev, i, res);
996 total += *res - lres;
997 if (error)
998 break;
999 }
1000 if (limit && --limit == 0)
1001 panic("kqueue: checkloop failed i=%d", i);
1002
1003 /*
1004 * Normally when fewer events are returned than requested
1005 * we can stop. However, if only spurious events were
1006 * collected the copyout will not bump (*res) and we have
1007 * to continue.
1008 */
1009 if (i < n && *res)
1010 break;
1011
1012 /*
1013 * Deal with an edge case where spurious events can cause
1014 * a loop to occur without moving the marker. This can
1015 * prevent kqueue_scan() from picking up new events which
1016 * race us. We must be sure to move the marker for this
1017 * case.
1018 *
1019 * NOTE: We do not want to move the marker if events
1020 * were scanned because normal kqueue operations
1021 * may reactivate events. Moving the marker in
1022 * that case could result in duplicates for the
1023 * same event.
1024 */
1025 if (i == 0) {
1026 lwkt_gettoken(tok);
1027 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe);
1028 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe);
1029 lwkt_reltoken(tok);
1030 }
1031 }
1032 lwkt_gettoken(tok);
1033 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe);
1034 lwkt_reltoken(tok);
1035
1036 /* Timeouts do not return EWOULDBLOCK. */
1037 if (error == EWOULDBLOCK)
1038 error = 0;
1039 return error;
1040 }
1041
1042 /*
1043 * MPALMOSTSAFE
1044 */
1045 int
1046 sys_kevent(struct kevent_args *uap)
1047 {
1048 struct thread *td = curthread;
1049 struct timespec ts, *tsp;
1050 struct kqueue *kq;
1051 struct file *fp = NULL;
1052 struct kevent_copyin_args *kap, ka;
1053 int error;
1054
1055 if (uap->timeout) {
1056 error = copyin(uap->timeout, &ts, sizeof(ts));
1057 if (error)
1058 return (error);
1059 tsp = &ts;
1060 } else {
1061 tsp = NULL;
1062 }
1063 fp = holdfp(td, uap->fd, -1);
1064 if (fp == NULL)
1065 return (EBADF);
1066 if (fp->f_type != DTYPE_KQUEUE) {
1067 fdrop(fp);
1068 return (EBADF);
1069 }
1070
1071 kq = (struct kqueue *)fp->f_data;
1072
1073 kap = &ka;
1074 kap->ka = uap;
1075 kap->pchanges = 0;
1076
1077 error = kern_kevent(kq, uap->nevents, &uap->sysmsg_result, kap,
1078 kevent_copyin, kevent_copyout, tsp, 0);
1079
1080 dropfp(td, uap->fd, fp);
1081
1082 return (error);
1083 }
1084
1085 /*
1086 * Efficiently load multiple file pointers. This significantly reduces
1087 * threaded overhead. When doing simple polling we can depend on the
1088 * per-thread (fd,fp) cache. With more descriptors, we batch.
1089 */
1090 static
1091 void
1092 floadkevfps(thread_t td, struct filedesc *fdp, struct kevent *kev,
1093 struct file **fp, int climit)
1094 {
1095 struct filterops *fops;
1096 int tdcache;
1097
1098 if (climit <= 2 && td->td_proc && td->td_proc->p_fd == fdp) {
1099 tdcache = 1;
1100 } else {
1101 tdcache = 0;
1102 spin_lock_shared(&fdp->fd_spin);
1103 }
1104
1105 while (climit) {
1106 *fp = NULL;
1107 if (kev->filter < 0 &&
1108 kev->filter + EVFILT_SYSCOUNT >= 0) {
1109 fops = sysfilt_ops[~kev->filter];
1110 if (fops->f_flags & FILTEROP_ISFD) {
1111 if (tdcache) {
1112 *fp = holdfp(td, kev->ident, -1);
1113 } else {
1114 *fp = holdfp_fdp_locked(fdp,
1115 kev->ident, -1);
1116 }
1117 }
1118 }
1119 --climit;
1120 ++fp;
1121 ++kev;
1122 }
1123 if (tdcache == 0)
1124 spin_unlock_shared(&fdp->fd_spin);
1125 }
1126
1127 /*
1128 * Register up to *countp kev's. Always registers at least 1.
1129 *
1130 * The number registered is returned in *countp.
1131 *
1132 * If an error occurs or a kev is flagged EV_RECEIPT, it is
1133 * processed and included in *countp, and processing then
1134 * stops.
1135 */
1136 int
1137 kqueue_register(struct kqueue *kq, struct kevent *kev, int *countp)
1138 {
1139 struct filedesc *fdp = kq->kq_fdp;
1140 struct klist *list = NULL;
1141 struct filterops *fops;
1142 struct file *fp[KQ_NEVENTS];
1143 struct knote *kn = NULL;
1144 struct thread *td;
1145 int error;
1146 int count;
1147 int climit;
1148 int closedcounter;
1149 struct knote_cache_list *cache_list;
1150
1151 td = curthread;
1152 climit = *countp;
1153 if (climit > KQ_NEVENTS)
1154 climit = KQ_NEVENTS;
1155 closedcounter = fdp->fd_closedcounter;
1156 floadkevfps(td, fdp, kev, fp, climit);
1157
1158 lwkt_getpooltoken(kq);
1159 count = 0;
1160
1161 /*
1162 * To avoid races, only one thread can register events on this
1163 * kqueue at a time.
1164 */
1165 while (__predict_false(kq->kq_regtd != NULL && kq->kq_regtd != td)) {
1166 kq->kq_state |= KQ_REGWAIT;
1167 tsleep(&kq->kq_regtd, 0, "kqreg", 0);
1168 }
1169 if (__predict_false(kq->kq_regtd != NULL)) {
1170 /* Recursive calling of kqueue_register() */
1171 td = NULL;
1172 } else {
1173 /* Owner of the kq_regtd, i.e. td != NULL */
1174 kq->kq_regtd = td;
1175 }
1176
1177 loop:
1178 if (kev->filter < 0) {
1179 if (kev->filter + EVFILT_SYSCOUNT < 0) {
1180 error = EINVAL;
1181 ++count;
1182 goto done;
1183 }
1184 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */
1185 } else {
1186 /*
1187 * XXX
1188 * filter attach routine is responsible for insuring that
1189 * the identifier can be attached to it.
1190 */
1191 error = EINVAL;
1192 ++count;
1193 goto done;
1194 }
1195
1196 if (fops->f_flags & FILTEROP_ISFD) {
1197 /* validate descriptor */
1198 if (fp[count] == NULL) {
1199 error = EBADF;
1200 ++count;
1201 goto done;
1202 }
1203 }
1204
1205 cache_list = &knote_cache_lists[mycpuid];
1206 if (SLIST_EMPTY(&cache_list->knote_cache)) {
1207 struct knote *new_kn;
1208
1209 new_kn = knote_alloc();
1210 crit_enter();
1211 SLIST_INSERT_HEAD(&cache_list->knote_cache, new_kn, kn_link);
1212 cache_list->knote_cache_cnt++;
1213 crit_exit();
1214 }
1215
1216 if (fp[count] != NULL) {
1217 list = &fp[count]->f_klist;
1218 } else if (kq->kq_knhashmask) {
1219 list = &kq->kq_knhash[
1220 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
1221 }
1222 if (list != NULL) {
1223 lwkt_getpooltoken(list);
1224 again:
1225 SLIST_FOREACH(kn, list, kn_link) {
1226 if (kn->kn_kq == kq &&
1227 kn->kn_filter == kev->filter &&
1228 kn->kn_id == kev->ident) {
1229 if (knote_acquire(kn) == 0)
1230 goto again;
1231 break;
1232 }
1233 }
1234 lwkt_relpooltoken(list);
1235 }
1236
1237 /*
1238 * NOTE: At this point if kn is non-NULL we will have acquired
1239 * it and set KN_PROCESSING.
1240 */
1241 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
1242 error = ENOENT;
1243 ++count;
1244 goto done;
1245 }
1246
1247 /*
1248 * kn now contains the matching knote, or NULL if no match
1249 */
1250 if (kev->flags & EV_ADD) {
1251 if (kn == NULL) {
1252 crit_enter();
1253 kn = SLIST_FIRST(&cache_list->knote_cache);
1254 if (kn == NULL) {
1255 crit_exit();
1256 kn = knote_alloc();
1257 } else {
1258 SLIST_REMOVE_HEAD(&cache_list->knote_cache,
1259 kn_link);
1260 cache_list->knote_cache_cnt--;
1261 crit_exit();
1262 }
1263 kn->kn_fp = fp[count];
1264 kn->kn_kq = kq;
1265 kn->kn_fop = fops;
1266
1267 /*
1268 * apply reference count to knote structure, and
1269 * do not release it at the end of this routine.
1270 */
1271 fp[count] = NULL; /* safety */
1272
1273 kn->kn_sfflags = kev->fflags;
1274 kn->kn_sdata = kev->data;
1275 kev->fflags = 0;
1276 kev->data = 0;
1277 kn->kn_kevent = *kev;
1278
1279 /*
1280 * KN_PROCESSING prevents the knote from getting
1281 * ripped out from under us while we are trying
1282 * to attach it, in case the attach blocks.
1283 */
1284 kn->kn_status = KN_PROCESSING;
1285 knote_attach(kn);
1286 if ((error = filter_attach(kn)) != 0) {
1287 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1288 knote_drop(kn);
1289 ++count;
1290 goto done;
1291 }
1292
1293 /*
1294 * Interlock against close races which either tried
1295 * to remove our knote while we were blocked or missed
1296 * it entirely prior to our attachment. We do not
1297 * want to end up with a knote on a closed descriptor.
1298 */
1299 if ((fops->f_flags & FILTEROP_ISFD) &&
1300 checkfdclosed(curthread, fdp, kev->ident, kn->kn_fp,
1301 closedcounter)) {
1302 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1303 }
1304 } else {
1305 /*
1306 * The user may change some filter values after the
1307 * initial EV_ADD, but doing so will not reset any
1308 * filter which have already been triggered.
1309 */
1310 KKASSERT(kn->kn_status & KN_PROCESSING);
1311 if (fops == &user_filtops) {
1312 filt_usertouch(kn, kev, EVENT_REGISTER);
1313 } else {
1314 kn->kn_sfflags = kev->fflags;
1315 kn->kn_sdata = kev->data;
1316 kn->kn_kevent.udata = kev->udata;
1317 }
1318 }
1319
1320 /*
1321 * Execute the filter event to immediately activate the
1322 * knote if necessary. If reprocessing events are pending
1323 * due to blocking above we do not run the filter here
1324 * but instead let knote_release() do it. Otherwise we
1325 * might run the filter on a deleted event.
1326 */
1327 if ((kn->kn_status & KN_REPROCESS) == 0) {
1328 if (filter_event(kn, 0))
1329 KNOTE_ACTIVATE(kn);
1330 }
1331 } else if (kev->flags & EV_DELETE) {
1332 /*
1333 * Delete the existing knote
1334 */
1335 knote_detach_and_drop(kn);
1336 error = 0;
1337 ++count;
1338 goto done;
1339 } else {
1340 /*
1341 * Modify an existing event.
1342 *
1343 * The user may change some filter values after the
1344 * initial EV_ADD, but doing so will not reset any
1345 * filter which have already been triggered.
1346 */
1347 KKASSERT(kn->kn_status & KN_PROCESSING);
1348 if (fops == &user_filtops) {
1349 filt_usertouch(kn, kev, EVENT_REGISTER);
1350 } else {
1351 kn->kn_sfflags = kev->fflags;
1352 kn->kn_sdata = kev->data;
1353 kn->kn_kevent.udata = kev->udata;
1354 }
1355
1356 /*
1357 * Execute the filter event to immediately activate the
1358 * knote if necessary. If reprocessing events are pending
1359 * due to blocking above we do not run the filter here
1360 * but instead let knote_release() do it. Otherwise we
1361 * might run the filter on a deleted event.
1362 */
1363 if ((kn->kn_status & KN_REPROCESS) == 0) {
1364 if (filter_event(kn, 0))
1365 KNOTE_ACTIVATE(kn);
1366 }
1367 }
1368
1369 /*
1370 * Disablement does not deactivate a knote here.
1371 */
1372 if ((kev->flags & EV_DISABLE) &&
1373 ((kn->kn_status & KN_DISABLED) == 0)) {
1374 kn->kn_status |= KN_DISABLED;
1375 }
1376
1377 /*
1378 * Re-enablement may have to immediately enqueue an active knote.
1379 */
1380 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
1381 kn->kn_status &= ~KN_DISABLED;
1382 if ((kn->kn_status & KN_ACTIVE) &&
1383 ((kn->kn_status & KN_QUEUED) == 0)) {
1384 knote_enqueue(kn);
1385 }
1386 }
1387
1388 /*
1389 * Handle any required reprocessing
1390 */
1391 knote_release(kn);
1392 /* kn may be invalid now */
1393
1394 /*
1395 * Loop control. We stop on errors (above), and also stop after
1396 * processing EV_RECEIPT, so the caller can process it.
1397 */
1398 ++count;
1399 if (kev->flags & EV_RECEIPT) {
1400 error = 0;
1401 goto done;
1402 }
1403 ++kev;
1404 if (count < climit) {
1405 if (fp[count-1]) /* drop unprocessed fp */
1406 fdrop(fp[count-1]);
1407 goto loop;
1408 }
1409
1410 /*
1411 * Cleanup
1412 */
1413 done:
1414 if (td != NULL) { /* Owner of the kq_regtd */
1415 kq->kq_regtd = NULL;
1416 if (__predict_false(kq->kq_state & KQ_REGWAIT)) {
1417 kq->kq_state &= ~KQ_REGWAIT;
1418 wakeup(&kq->kq_regtd);
1419 }
1420 }
1421 lwkt_relpooltoken(kq);
1422
1423 /*
1424 * Drop unprocessed file pointers
1425 */
1426 *countp = count;
1427 if (count && fp[count-1])
1428 fdrop(fp[count-1]);
1429 while (count < climit) {
1430 if (fp[count])
1431 fdrop(fp[count]);
1432 ++count;
1433 }
1434 return (error);
1435 }
1436
1437 /*
1438 * Scan the kqueue, return the number of active events placed in kevp up
1439 * to count.
1440 *
1441 * Continuous mode events may get recycled, do not continue scanning past
1442 * marker unless no events have been collected.
1443 */
1444 static int
1445 kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count,
1446 struct knote *marker, int closedcounter)
1447 {
1448 struct knote *kn, local_marker;
1449 thread_t td = curthread;
1450 int total;
1451
1452 total = 0;
1453 local_marker.kn_filter = EVFILT_MARKER;
1454 local_marker.kn_status = KN_PROCESSING;
1455
1456 lwkt_getpooltoken(kq);
1457
1458 /*
1459 * Collect events.
1460 */
1461 TAILQ_INSERT_HEAD(&kq->kq_knpend, &local_marker, kn_tqe);
1462 while (count) {
1463 kn = TAILQ_NEXT(&local_marker, kn_tqe);
1464 if (kn->kn_filter == EVFILT_MARKER) {
1465 /* Marker reached, we are done */
1466 if (kn == marker)
1467 break;
1468
1469 /* Move local marker past some other threads marker */
1470 kn = TAILQ_NEXT(kn, kn_tqe);
1471 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe);
1472 TAILQ_INSERT_BEFORE(kn, &local_marker, kn_tqe);
1473 continue;
1474 }
1475
1476 /*
1477 * We can't skip a knote undergoing processing, otherwise
1478 * we risk not returning it when the user process expects
1479 * it should be returned. Sleep and retry.
1480 */
1481 if (knote_acquire(kn) == 0)
1482 continue;
1483
1484 /*
1485 * Remove the event for processing.
1486 *
1487 * WARNING! We must leave KN_QUEUED set to prevent the
1488 * event from being KNOTE_ACTIVATE()d while
1489 * the queue state is in limbo, in case we
1490 * block.
1491 */
1492 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe);
1493 kq->kq_count--;
1494
1495 /*
1496 * We have to deal with an extremely important race against
1497 * file descriptor close()s here. The file descriptor can
1498 * disappear MPSAFE, and there is a small window of
1499 * opportunity between that and the call to knote_fdclose().
1500 *
1501 * If we hit that window here while doselect or dopoll is
1502 * trying to delete a spurious event they will not be able
1503 * to match up the event against a knote and will go haywire.
1504 */
1505 if ((kn->kn_fop->f_flags & FILTEROP_ISFD) &&
1506 checkfdclosed(td, kq->kq_fdp, kn->kn_kevent.ident,
1507 kn->kn_fp, closedcounter)) {
1508 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1509 }
1510
1511 if (kn->kn_status & KN_DISABLED) {
1512 /*
1513 * If disabled we ensure the event is not queued
1514 * but leave its active bit set. On re-enablement
1515 * the event may be immediately triggered.
1516 */
1517 kn->kn_status &= ~KN_QUEUED;
1518 } else if ((kn->kn_flags & EV_ONESHOT) == 0 &&
1519 (kn->kn_status & KN_DELETING) == 0 &&
1520 filter_event(kn, 0) == 0) {
1521 /*
1522 * If not running in one-shot mode and the event
1523 * is no longer present we ensure it is removed
1524 * from the queue and ignore it.
1525 */
1526 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
1527 } else {
1528 /*
1529 * Post the event
1530 */
1531 if (kn->kn_fop == &user_filtops)
1532 filt_usertouch(kn, kevp, EVENT_PROCESS);
1533 else
1534 *kevp = kn->kn_kevent;
1535 ++kevp;
1536 ++total;
1537 --count;
1538
1539 if (kn->kn_flags & EV_ONESHOT) {
1540 kn->kn_status &= ~KN_QUEUED;
1541 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1542 } else {
1543 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
1544 if (kn->kn_flags & EV_CLEAR) {
1545 kn->kn_data = 0;
1546 kn->kn_fflags = 0;
1547 }
1548 if (kn->kn_flags & EV_DISPATCH) {
1549 kn->kn_status |= KN_DISABLED;
1550 }
1551 kn->kn_status &= ~(KN_QUEUED |
1552 KN_ACTIVE);
1553 } else {
1554 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe);
1555 kq->kq_count++;
1556 }
1557 }
1558 }
1559
1560 /*
1561 * Handle any post-processing states
1562 */
1563 knote_release(kn);
1564 }
1565 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe);
1566
1567 lwkt_relpooltoken(kq);
1568 return (total);
1569 }
1570
1571 /*
1572 * XXX
1573 * This could be expanded to call kqueue_scan, if desired.
1574 *
1575 * MPSAFE
1576 */
1577 static int
1578 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
1579 {
1580 return (ENXIO);
1581 }
1582
1583 /*
1584 * MPSAFE
1585 */
1586 static int
1587 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
1588 {
1589 return (ENXIO);
1590 }
1591
1592 /*
1593 * MPALMOSTSAFE
1594 */
1595 static int
1596 kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
1597 struct ucred *cred, struct sysmsg *msg)
1598 {
1599 struct kqueue *kq;
1600 int error;
1601
1602 kq = (struct kqueue *)fp->f_data;
1603 lwkt_getpooltoken(kq);
1604 switch(com) {
1605 case FIOASYNC:
1606 if (*(int *)data)
1607 kq->kq_state |= KQ_ASYNC;
1608 else
1609 kq->kq_state &= ~KQ_ASYNC;
1610 error = 0;
1611 break;
1612 case FIOSETOWN:
1613 error = fsetown(*(int *)data, &kq->kq_sigio);
1614 break;
1615 default:
1616 error = ENOTTY;
1617 break;
1618 }
1619 lwkt_relpooltoken(kq);
1620 return (error);
1621 }
1622
1623 /*
1624 * MPSAFE
1625 */
1626 static int
1627 kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred)
1628 {
1629 struct kqueue *kq = (struct kqueue *)fp->f_data;
1630
1631 bzero((void *)st, sizeof(*st));
1632 st->st_size = kq->kq_count;
1633 st->st_blksize = sizeof(struct kevent);
1634 st->st_mode = S_IFIFO;
1635 return (0);
1636 }
1637
1638 /*
1639 * MPSAFE
1640 */
1641 static int
1642 kqueue_close(struct file *fp)
1643 {
1644 struct kqueue *kq = (struct kqueue *)fp->f_data;
1645
1646 kqueue_terminate(kq);
1647
1648 fp->f_data = NULL;
1649 funsetown(&kq->kq_sigio);
1650
1651 kfree(kq, M_KQUEUE);
1652 return (0);
1653 }
1654
1655 static void
1656 kqueue_wakeup(struct kqueue *kq)
1657 {
1658 if (kq->kq_sleep_cnt) {
1659 u_int sleep_cnt = kq->kq_sleep_cnt;
1660
1661 kq->kq_sleep_cnt = 0;
1662 if (sleep_cnt == 1)
1663 wakeup_one(kq);
1664 else
1665 wakeup(kq);
1666 }
1667 KNOTE(&kq->kq_kqinfo.ki_note, 0);
1668 }
1669
1670 /*
1671 * Calls filterops f_attach function, acquiring mplock if filter is not
1672 * marked as FILTEROP_MPSAFE.
1673 *
1674 * Caller must be holding the related kq token
1675 */
1676 static int
1677 filter_attach(struct knote *kn)
1678 {
1679 int ret;
1680
1681 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) {
1682 ret = kn->kn_fop->f_attach(kn);
1683 } else {
1684 get_mplock();
1685 ret = kn->kn_fop->f_attach(kn);
1686 rel_mplock();
1687 }
1688 return (ret);
1689 }
1690
1691 /*
1692 * Detach the knote and drop it, destroying the knote.
1693 *
1694 * Calls filterops f_detach function, acquiring mplock if filter is not
1695 * marked as FILTEROP_MPSAFE.
1696 *
1697 * Caller must be holding the related kq token
1698 */
1699 static void
1700 knote_detach_and_drop(struct knote *kn)
1701 {
1702 kn->kn_status |= KN_DELETING | KN_REPROCESS;
1703 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) {
1704 kn->kn_fop->f_detach(kn);
1705 } else {
1706 get_mplock();
1707 kn->kn_fop->f_detach(kn);
1708 rel_mplock();
1709 }
1710 knote_drop(kn);
1711 }
1712
1713 /*
1714 * Calls filterops f_event function, acquiring mplock if filter is not
1715 * marked as FILTEROP_MPSAFE.
1716 *
1717 * If the knote is in the middle of being created or deleted we cannot
1718 * safely call the filter op.
1719 *
1720 * Caller must be holding the related kq token
1721 */
1722 static int
1723 filter_event(struct knote *kn, long hint)
1724 {
1725 int ret;
1726
1727 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) {
1728 ret = kn->kn_fop->f_event(kn, hint);
1729 } else {
1730 get_mplock();
1731 ret = kn->kn_fop->f_event(kn, hint);
1732 rel_mplock();
1733 }
1734 return (ret);
1735 }
1736
1737 /*
1738 * Walk down a list of knotes, activating them if their event has triggered.
1739 *
1740 * If we encounter any knotes which are undergoing processing we just mark
1741 * them for reprocessing and do not try to [re]activate the knote. However,
1742 * if a hint is being passed we have to wait and that makes things a bit
1743 * sticky.
1744 */
1745 void
1746 knote(struct klist *list, long hint)
1747 {
1748 struct kqueue *kq;
1749 struct knote *kn;
1750 struct knote *kntmp;
1751
1752 lwkt_getpooltoken(list);
1753 restart:
1754 SLIST_FOREACH(kn, list, kn_next) {
1755 kq = kn->kn_kq;
1756 lwkt_getpooltoken(kq);
1757
1758 /* temporary verification hack */
1759 SLIST_FOREACH(kntmp, list, kn_next) {
1760 if (kn == kntmp)
1761 break;
1762 }
1763 if (kn != kntmp || kn->kn_kq != kq) {
1764 lwkt_relpooltoken(kq);
1765 goto restart;
1766 }
1767
1768 if (kn->kn_status & KN_PROCESSING) {
1769 /*
1770 * Someone else is processing the knote, ask the
1771 * other thread to reprocess it and don't mess
1772 * with it otherwise.
1773 */
1774 if (hint == 0) {
1775 kn->kn_status |= KN_REPROCESS;
1776 lwkt_relpooltoken(kq);
1777 continue;
1778 }
1779
1780 /*
1781 * If the hint is non-zero we have to wait or risk
1782 * losing the state the caller is trying to update.
1783 *
1784 * XXX This is a real problem, certain process
1785 * and signal filters will bump kn_data for
1786 * already-processed notes more than once if
1787 * we restart the list scan. FIXME.
1788 */
1789 kn->kn_status |= KN_WAITING | KN_REPROCESS;
1790 tsleep(kn, 0, "knotec", hz);
1791 lwkt_relpooltoken(kq);
1792 goto restart;
1793 }
1794
1795 /*
1796 * Become the reprocessing master ourselves.
1797 *
1798 * If hint is non-zero running the event is mandatory
1799 * when not deleting so do it whether reprocessing is
1800 * set or not.
1801 */
1802 kn->kn_status |= KN_PROCESSING;
1803 if ((kn->kn_status & KN_DELETING) == 0) {
1804 if (filter_event(kn, hint))
1805 KNOTE_ACTIVATE(kn);
1806 }
1807 if (knote_release(kn)) {
1808 lwkt_relpooltoken(kq);
1809 goto restart;
1810 }
1811 lwkt_relpooltoken(kq);
1812 }
1813 lwkt_relpooltoken(list);
1814 }
1815
1816 /*
1817 * Insert knote at head of klist.
1818 *
1819 * This function may only be called via a filter function and thus
1820 * kq_token should already be held and marked for processing.
1821 */
1822 void
1823 knote_insert(struct klist *klist, struct knote *kn)
1824 {
1825 lwkt_getpooltoken(klist);
1826 KKASSERT(kn->kn_status & KN_PROCESSING);
1827 SLIST_INSERT_HEAD(klist, kn, kn_next);
1828 lwkt_relpooltoken(klist);
1829 }
1830
1831 /*
1832 * Remove knote from a klist
1833 *
1834 * This function may only be called via a filter function and thus
1835 * kq_token should already be held and marked for processing.
1836 */
1837 void
1838 knote_remove(struct klist *klist, struct knote *kn)
1839 {
1840 lwkt_getpooltoken(klist);
1841 KKASSERT(kn->kn_status & KN_PROCESSING);
1842 SLIST_REMOVE(klist, kn, knote, kn_next);
1843 lwkt_relpooltoken(klist);
1844 }
1845
1846 void
1847 knote_assume_knotes(struct kqinfo *src, struct kqinfo *dst,
1848 struct filterops *ops, void *hook)
1849 {
1850 struct kqueue *kq;
1851 struct knote *kn;
1852
1853 lwkt_getpooltoken(&src->ki_note);
1854 lwkt_getpooltoken(&dst->ki_note);
1855 while ((kn = SLIST_FIRST(&src->ki_note)) != NULL) {
1856 kq = kn->kn_kq;
1857 lwkt_getpooltoken(kq);
1858 if (SLIST_FIRST(&src->ki_note) != kn || kn->kn_kq != kq) {
1859 lwkt_relpooltoken(kq);
1860 continue;
1861 }
1862 if (knote_acquire(kn)) {
1863 knote_remove(&src->ki_note, kn);
1864 kn->kn_fop = ops;
1865 kn->kn_hook = hook;
1866 knote_insert(&dst->ki_note, kn);
1867 knote_release(kn);
1868 /* kn may be invalid now */
1869 }
1870 lwkt_relpooltoken(kq);
1871 }
1872 lwkt_relpooltoken(&dst->ki_note);
1873 lwkt_relpooltoken(&src->ki_note);
1874 }
1875
1876 /*
1877 * Remove all knotes referencing a specified fd
1878 */
1879 void
1880 knote_fdclose(struct file *fp, struct filedesc *fdp, int fd)
1881 {
1882 struct kqueue *kq;
1883 struct knote *kn;
1884 struct knote *kntmp;
1885
1886 lwkt_getpooltoken(&fp->f_klist);
1887 restart:
1888 SLIST_FOREACH(kn, &fp->f_klist, kn_link) {
1889 if (kn->kn_kq->kq_fdp == fdp && kn->kn_id == fd) {
1890 kq = kn->kn_kq;
1891 lwkt_getpooltoken(kq);
1892
1893 /* temporary verification hack */
1894 SLIST_FOREACH(kntmp, &fp->f_klist, kn_link) {
1895 if (kn == kntmp)
1896 break;
1897 }
1898 if (kn != kntmp || kn->kn_kq->kq_fdp != fdp ||
1899 kn->kn_id != fd || kn->kn_kq != kq) {
1900 lwkt_relpooltoken(kq);
1901 goto restart;
1902 }
1903 if (knote_acquire(kn))
1904 knote_detach_and_drop(kn);
1905 lwkt_relpooltoken(kq);
1906 goto restart;
1907 }
1908 }
1909 lwkt_relpooltoken(&fp->f_klist);
1910 }
1911
1912 /*
1913 * Low level attach function.
1914 *
1915 * The knote should already be marked for processing.
1916 * Caller must hold the related kq token.
1917 */
1918 static void
1919 knote_attach(struct knote *kn)
1920 {
1921 struct klist *list;
1922 struct kqueue *kq = kn->kn_kq;
1923
1924 if (kn->kn_fop->f_flags & FILTEROP_ISFD) {
1925 KKASSERT(kn->kn_fp);
1926 list = &kn->kn_fp->f_klist;
1927 } else {
1928 if (kq->kq_knhashmask == 0)
1929 kq->kq_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
1930 &kq->kq_knhashmask);
1931 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
1932 }
1933 lwkt_getpooltoken(list);
1934 SLIST_INSERT_HEAD(list, kn, kn_link);
1935 lwkt_relpooltoken(list);
1936 TAILQ_INSERT_HEAD(&kq->kq_knlist, kn, kn_kqlink);
1937 }
1938
1939 /*
1940 * Low level drop function.
1941 *
1942 * The knote should already be marked for processing.
1943 * Caller must hold the related kq token.
1944 */
1945 static void
1946 knote_drop(struct knote *kn)
1947 {
1948 struct kqueue *kq;
1949 struct klist *list;
1950
1951 kq = kn->kn_kq;
1952
1953 if (kn->kn_fop->f_flags & FILTEROP_ISFD)
1954 list = &kn->kn_fp->f_klist;
1955 else
1956 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
1957
1958 lwkt_getpooltoken(list);
1959 SLIST_REMOVE(list, kn, knote, kn_link);
1960 lwkt_relpooltoken(list);
1961 TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink);
1962 if (kn->kn_status & KN_QUEUED)
1963 knote_dequeue(kn);
1964 if (kn->kn_fop->f_flags & FILTEROP_ISFD) {
1965 fdrop(kn->kn_fp);
1966 kn->kn_fp = NULL;
1967 }
1968 knote_free(kn);
1969 }
1970
1971 /*
1972 * Low level enqueue function.
1973 *
1974 * The knote should already be marked for processing.
1975 * Caller must be holding the kq token
1976 */
1977 static void
1978 knote_enqueue(struct knote *kn)
1979 {
1980 struct kqueue *kq = kn->kn_kq;
1981
1982 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
1983 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe);
1984 kn->kn_status |= KN_QUEUED;
1985 ++kq->kq_count;
1986
1987 /*
1988 * Send SIGIO on request (typically set up as a mailbox signal)
1989 */
1990 if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1)
1991 pgsigio(kq->kq_sigio, SIGIO, 0);
1992
1993 kqueue_wakeup(kq);
1994 }
1995
1996 /*
1997 * Low level dequeue function.
1998 *
1999 * The knote should already be marked for processing.
2000 * Caller must be holding the kq token
2001 */
2002 static void
2003 knote_dequeue(struct knote *kn)
2004 {
2005 struct kqueue *kq = kn->kn_kq;
2006
2007 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
2008 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe);
2009 kn->kn_status &= ~KN_QUEUED;
2010 kq->kq_count--;
2011 }
2012
2013 static struct knote *
2014 knote_alloc(void)
2015 {
2016 return kmalloc(sizeof(struct knote), M_KQUEUE, M_WAITOK);
2017 }
2018
2019 static void
2020 knote_free(struct knote *kn)
2021 {
2022 struct knote_cache_list *cache_list;
2023
2024 cache_list = &knote_cache_lists[mycpuid];
2025 if (cache_list->knote_cache_cnt < KNOTE_CACHE_MAX) {
2026 crit_enter();
2027 SLIST_INSERT_HEAD(&cache_list->knote_cache, kn, kn_link);
2028 cache_list->knote_cache_cnt++;
2029 crit_exit();
2030 return;
2031 }
2032 kfree(kn, M_KQUEUE);
2033 }
2034
2035 struct sleepinfo {
2036 void *ident;
2037 int timedout;
2038 };
2039
2040 static void
2041 precise_sleep_intr(systimer_t info, int in_ipi, struct intrframe *frame)
2042 {
2043 struct sleepinfo *si;
2044
2045 si = info->data;
2046 si->timedout = 1;
2047 wakeup(si->ident);
2048 }
2049
2050 static int
2051 precise_sleep(void *ident, int flags, const char *wmesg, int us)
2052 {
2053 struct systimer info;
2054 struct sleepinfo si = {
2055 .ident = ident,
2056 .timedout = 0,
2057 };
2058 int r;
2059
2060 tsleep_interlock(ident, flags);
2061 systimer_init_oneshot(&info, precise_sleep_intr, &si,
2062 us == 0 ? 1 : us);
2063 r = tsleep(ident, flags | PINTERLOCKED, wmesg, 0);
2064 systimer_del(&info);
2065 if (si.timedout)
2066 r = EWOULDBLOCK;
2067
2068 return r;
2069 }
DragonFly BSD