FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_event.c
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
5 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org>
6 * Copyright (c) 2009 Apple, Inc.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33
34 #include "opt_ktrace.h"
35 #include "opt_kqueue.h"
36
37 #ifdef COMPAT_FREEBSD11
38 #define _WANT_FREEBSD11_KEVENT
39 #endif
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/capsicum.h>
44 #include <sys/kernel.h>
45 #include <sys/limits.h>
46 #include <sys/lock.h>
47 #include <sys/mutex.h>
48 #include <sys/proc.h>
49 #include <sys/malloc.h>
50 #include <sys/unistd.h>
51 #include <sys/file.h>
52 #include <sys/filedesc.h>
53 #include <sys/filio.h>
54 #include <sys/fcntl.h>
55 #include <sys/kthread.h>
56 #include <sys/selinfo.h>
57 #include <sys/queue.h>
58 #include <sys/event.h>
59 #include <sys/eventvar.h>
60 #include <sys/poll.h>
61 #include <sys/protosw.h>
62 #include <sys/resourcevar.h>
63 #include <sys/sigio.h>
64 #include <sys/signalvar.h>
65 #include <sys/socket.h>
66 #include <sys/socketvar.h>
67 #include <sys/stat.h>
68 #include <sys/sysctl.h>
69 #include <sys/sysproto.h>
70 #include <sys/syscallsubr.h>
71 #include <sys/taskqueue.h>
72 #include <sys/uio.h>
73 #include <sys/user.h>
74 #ifdef KTRACE
75 #include <sys/ktrace.h>
76 #endif
77 #include <machine/atomic.h>
78
79 #include <vm/uma.h>
80
81 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
82
83 /*
84 * This lock is used if multiple kq locks are required. This possibly
85 * should be made into a per proc lock.
86 */
87 static struct mtx kq_global;
88 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF);
89 #define KQ_GLOBAL_LOCK(lck, haslck) do { \
90 if (!haslck) \
91 mtx_lock(lck); \
92 haslck = 1; \
93 } while (0)
94 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \
95 if (haslck) \
96 mtx_unlock(lck); \
97 haslck = 0; \
98 } while (0)
99
100 TASKQUEUE_DEFINE_THREAD(kqueue_ctx);
101
102 static int kevent_copyout(void *arg, struct kevent *kevp, int count);
103 static int kevent_copyin(void *arg, struct kevent *kevp, int count);
104 static int kqueue_register(struct kqueue *kq, struct kevent *kev,
105 struct thread *td, int mflag);
106 static int kqueue_acquire(struct file *fp, struct kqueue **kqp);
107 static void kqueue_release(struct kqueue *kq, int locked);
108 static void kqueue_destroy(struct kqueue *kq);
109 static void kqueue_drain(struct kqueue *kq, struct thread *td);
110 static int kqueue_expand(struct kqueue *kq, struct filterops *fops,
111 uintptr_t ident, int mflag);
112 static void kqueue_task(void *arg, int pending);
113 static int kqueue_scan(struct kqueue *kq, int maxevents,
114 struct kevent_copyops *k_ops,
115 const struct timespec *timeout,
116 struct kevent *keva, struct thread *td);
117 static void kqueue_wakeup(struct kqueue *kq);
118 static struct filterops *kqueue_fo_find(int filt);
119 static void kqueue_fo_release(int filt);
120 struct g_kevent_args;
121 static int kern_kevent_generic(struct thread *td,
122 struct g_kevent_args *uap,
123 struct kevent_copyops *k_ops, const char *struct_name);
124
125 static fo_ioctl_t kqueue_ioctl;
126 static fo_poll_t kqueue_poll;
127 static fo_kqfilter_t kqueue_kqfilter;
128 static fo_stat_t kqueue_stat;
129 static fo_close_t kqueue_close;
130 static fo_fill_kinfo_t kqueue_fill_kinfo;
131
132 static struct fileops kqueueops = {
133 .fo_read = invfo_rdwr,
134 .fo_write = invfo_rdwr,
135 .fo_truncate = invfo_truncate,
136 .fo_ioctl = kqueue_ioctl,
137 .fo_poll = kqueue_poll,
138 .fo_kqfilter = kqueue_kqfilter,
139 .fo_stat = kqueue_stat,
140 .fo_close = kqueue_close,
141 .fo_chmod = invfo_chmod,
142 .fo_chown = invfo_chown,
143 .fo_sendfile = invfo_sendfile,
144 .fo_fill_kinfo = kqueue_fill_kinfo,
145 };
146
147 static int knote_attach(struct knote *kn, struct kqueue *kq);
148 static void knote_drop(struct knote *kn, struct thread *td);
149 static void knote_drop_detached(struct knote *kn, struct thread *td);
150 static void knote_enqueue(struct knote *kn);
151 static void knote_dequeue(struct knote *kn);
152 static void knote_init(void);
153 static struct knote *knote_alloc(int mflag);
154 static void knote_free(struct knote *kn);
155
156 static void filt_kqdetach(struct knote *kn);
157 static int filt_kqueue(struct knote *kn, long hint);
158 static int filt_procattach(struct knote *kn);
159 static void filt_procdetach(struct knote *kn);
160 static int filt_proc(struct knote *kn, long hint);
161 static int filt_fileattach(struct knote *kn);
162 static void filt_timerexpire(void *knx);
163 static void filt_timerexpire_l(struct knote *kn, bool proc_locked);
164 static int filt_timerattach(struct knote *kn);
165 static void filt_timerdetach(struct knote *kn);
166 static void filt_timerstart(struct knote *kn, sbintime_t to);
167 static void filt_timertouch(struct knote *kn, struct kevent *kev,
168 u_long type);
169 static int filt_timervalidate(struct knote *kn, sbintime_t *to);
170 static int filt_timer(struct knote *kn, long hint);
171 static int filt_userattach(struct knote *kn);
172 static void filt_userdetach(struct knote *kn);
173 static int filt_user(struct knote *kn, long hint);
174 static void filt_usertouch(struct knote *kn, struct kevent *kev,
175 u_long type);
176
177 static struct filterops file_filtops = {
178 .f_isfd = 1,
179 .f_attach = filt_fileattach,
180 };
181 static struct filterops kqread_filtops = {
182 .f_isfd = 1,
183 .f_detach = filt_kqdetach,
184 .f_event = filt_kqueue,
185 };
186 /* XXX - move to kern_proc.c? */
187 static struct filterops proc_filtops = {
188 .f_isfd = 0,
189 .f_attach = filt_procattach,
190 .f_detach = filt_procdetach,
191 .f_event = filt_proc,
192 };
193 static struct filterops timer_filtops = {
194 .f_isfd = 0,
195 .f_attach = filt_timerattach,
196 .f_detach = filt_timerdetach,
197 .f_event = filt_timer,
198 .f_touch = filt_timertouch,
199 };
200 static struct filterops user_filtops = {
201 .f_attach = filt_userattach,
202 .f_detach = filt_userdetach,
203 .f_event = filt_user,
204 .f_touch = filt_usertouch,
205 };
206
207 static uma_zone_t knote_zone;
208 static unsigned int __exclusive_cache_line kq_ncallouts;
209 static unsigned int kq_calloutmax = 4 * 1024;
210 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
211 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
212
213 /* XXX - ensure not influx ? */
214 #define KNOTE_ACTIVATE(kn, islock) do { \
215 if ((islock)) \
216 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \
217 else \
218 KQ_LOCK((kn)->kn_kq); \
219 (kn)->kn_status |= KN_ACTIVE; \
220 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
221 knote_enqueue((kn)); \
222 if (!(islock)) \
223 KQ_UNLOCK((kn)->kn_kq); \
224 } while (0)
225 #define KQ_LOCK(kq) do { \
226 mtx_lock(&(kq)->kq_lock); \
227 } while (0)
228 #define KQ_FLUX_WAKEUP(kq) do { \
229 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \
230 (kq)->kq_state &= ~KQ_FLUXWAIT; \
231 wakeup((kq)); \
232 } \
233 } while (0)
234 #define KQ_UNLOCK_FLUX(kq) do { \
235 KQ_FLUX_WAKEUP(kq); \
236 mtx_unlock(&(kq)->kq_lock); \
237 } while (0)
238 #define KQ_UNLOCK(kq) do { \
239 mtx_unlock(&(kq)->kq_lock); \
240 } while (0)
241 #define KQ_OWNED(kq) do { \
242 mtx_assert(&(kq)->kq_lock, MA_OWNED); \
243 } while (0)
244 #define KQ_NOTOWNED(kq) do { \
245 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \
246 } while (0)
247
248 static struct knlist *
249 kn_list_lock(struct knote *kn)
250 {
251 struct knlist *knl;
252
253 knl = kn->kn_knlist;
254 if (knl != NULL)
255 knl->kl_lock(knl->kl_lockarg);
256 return (knl);
257 }
258
259 static void
260 kn_list_unlock(struct knlist *knl)
261 {
262 bool do_free;
263
264 if (knl == NULL)
265 return;
266 do_free = knl->kl_autodestroy && knlist_empty(knl);
267 knl->kl_unlock(knl->kl_lockarg);
268 if (do_free) {
269 knlist_destroy(knl);
270 free(knl, M_KQUEUE);
271 }
272 }
273
274 static bool
275 kn_in_flux(struct knote *kn)
276 {
277
278 return (kn->kn_influx > 0);
279 }
280
281 static void
282 kn_enter_flux(struct knote *kn)
283 {
284
285 KQ_OWNED(kn->kn_kq);
286 MPASS(kn->kn_influx < INT_MAX);
287 kn->kn_influx++;
288 }
289
290 static bool
291 kn_leave_flux(struct knote *kn)
292 {
293
294 KQ_OWNED(kn->kn_kq);
295 MPASS(kn->kn_influx > 0);
296 kn->kn_influx--;
297 return (kn->kn_influx == 0);
298 }
299
300 #define KNL_ASSERT_LOCK(knl, islocked) do { \
301 if (islocked) \
302 KNL_ASSERT_LOCKED(knl); \
303 else \
304 KNL_ASSERT_UNLOCKED(knl); \
305 } while (0)
306 #ifdef INVARIANTS
307 #define KNL_ASSERT_LOCKED(knl) do { \
308 knl->kl_assert_lock((knl)->kl_lockarg, LA_LOCKED); \
309 } while (0)
310 #define KNL_ASSERT_UNLOCKED(knl) do { \
311 knl->kl_assert_lock((knl)->kl_lockarg, LA_UNLOCKED); \
312 } while (0)
313 #else /* !INVARIANTS */
314 #define KNL_ASSERT_LOCKED(knl) do {} while (0)
315 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
316 #endif /* INVARIANTS */
317
318 #ifndef KN_HASHSIZE
319 #define KN_HASHSIZE 64 /* XXX should be tunable */
320 #endif
321
322 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
323
324 static int
325 filt_nullattach(struct knote *kn)
326 {
327
328 return (ENXIO);
329 };
330
331 struct filterops null_filtops = {
332 .f_isfd = 0,
333 .f_attach = filt_nullattach,
334 };
335
336 /* XXX - make SYSINIT to add these, and move into respective modules. */
337 extern struct filterops sig_filtops;
338 extern struct filterops fs_filtops;
339
340 /*
341 * Table for all system-defined filters.
342 */
343 static struct mtx filterops_lock;
344 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops",
345 MTX_DEF);
346 static struct {
347 struct filterops *for_fop;
348 int for_nolock;
349 int for_refcnt;
350 } sysfilt_ops[EVFILT_SYSCOUNT] = {
351 { &file_filtops, 1 }, /* EVFILT_READ */
352 { &file_filtops, 1 }, /* EVFILT_WRITE */
353 { &null_filtops }, /* EVFILT_AIO */
354 { &file_filtops, 1 }, /* EVFILT_VNODE */
355 { &proc_filtops, 1 }, /* EVFILT_PROC */
356 { &sig_filtops, 1 }, /* EVFILT_SIGNAL */
357 { &timer_filtops, 1 }, /* EVFILT_TIMER */
358 { &file_filtops, 1 }, /* EVFILT_PROCDESC */
359 { &fs_filtops, 1 }, /* EVFILT_FS */
360 { &null_filtops }, /* EVFILT_LIO */
361 { &user_filtops, 1 }, /* EVFILT_USER */
362 { &null_filtops }, /* EVFILT_SENDFILE */
363 { &file_filtops, 1 }, /* EVFILT_EMPTY */
364 };
365
366 /*
367 * Simple redirection for all cdevsw style objects to call their fo_kqfilter
368 * method.
369 */
370 static int
371 filt_fileattach(struct knote *kn)
372 {
373
374 return (fo_kqfilter(kn->kn_fp, kn));
375 }
376
377 /*ARGSUSED*/
378 static int
379 kqueue_kqfilter(struct file *fp, struct knote *kn)
380 {
381 struct kqueue *kq = kn->kn_fp->f_data;
382
383 if (kn->kn_filter != EVFILT_READ)
384 return (EINVAL);
385
386 kn->kn_status |= KN_KQUEUE;
387 kn->kn_fop = &kqread_filtops;
388 knlist_add(&kq->kq_sel.si_note, kn, 0);
389
390 return (0);
391 }
392
393 static void
394 filt_kqdetach(struct knote *kn)
395 {
396 struct kqueue *kq = kn->kn_fp->f_data;
397
398 knlist_remove(&kq->kq_sel.si_note, kn, 0);
399 }
400
401 /*ARGSUSED*/
402 static int
403 filt_kqueue(struct knote *kn, long hint)
404 {
405 struct kqueue *kq = kn->kn_fp->f_data;
406
407 kn->kn_data = kq->kq_count;
408 return (kn->kn_data > 0);
409 }
410
411 /* XXX - move to kern_proc.c? */
412 static int
413 filt_procattach(struct knote *kn)
414 {
415 struct proc *p;
416 int error;
417 bool exiting, immediate;
418
419 exiting = immediate = false;
420 if (kn->kn_sfflags & NOTE_EXIT)
421 p = pfind_any(kn->kn_id);
422 else
423 p = pfind(kn->kn_id);
424 if (p == NULL)
425 return (ESRCH);
426 if (p->p_flag & P_WEXIT)
427 exiting = true;
428
429 if ((error = p_cansee(curthread, p))) {
430 PROC_UNLOCK(p);
431 return (error);
432 }
433
434 kn->kn_ptr.p_proc = p;
435 kn->kn_flags |= EV_CLEAR; /* automatically set */
436
437 /*
438 * Internal flag indicating registration done by kernel for the
439 * purposes of getting a NOTE_CHILD notification.
440 */
441 if (kn->kn_flags & EV_FLAG2) {
442 kn->kn_flags &= ~EV_FLAG2;
443 kn->kn_data = kn->kn_sdata; /* ppid */
444 kn->kn_fflags = NOTE_CHILD;
445 kn->kn_sfflags &= ~(NOTE_EXIT | NOTE_EXEC | NOTE_FORK);
446 immediate = true; /* Force immediate activation of child note. */
447 }
448 /*
449 * Internal flag indicating registration done by kernel (for other than
450 * NOTE_CHILD).
451 */
452 if (kn->kn_flags & EV_FLAG1) {
453 kn->kn_flags &= ~EV_FLAG1;
454 }
455
456 knlist_add(p->p_klist, kn, 1);
457
458 /*
459 * Immediately activate any child notes or, in the case of a zombie
460 * target process, exit notes. The latter is necessary to handle the
461 * case where the target process, e.g. a child, dies before the kevent
462 * is registered.
463 */
464 if (immediate || (exiting && filt_proc(kn, NOTE_EXIT)))
465 KNOTE_ACTIVATE(kn, 0);
466
467 PROC_UNLOCK(p);
468
469 return (0);
470 }
471
472 /*
473 * The knote may be attached to a different process, which may exit,
474 * leaving nothing for the knote to be attached to. So when the process
475 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
476 * it will be deleted when read out. However, as part of the knote deletion,
477 * this routine is called, so a check is needed to avoid actually performing
478 * a detach, because the original process does not exist any more.
479 */
480 /* XXX - move to kern_proc.c? */
481 static void
482 filt_procdetach(struct knote *kn)
483 {
484
485 knlist_remove(kn->kn_knlist, kn, 0);
486 kn->kn_ptr.p_proc = NULL;
487 }
488
489 /* XXX - move to kern_proc.c? */
490 static int
491 filt_proc(struct knote *kn, long hint)
492 {
493 struct proc *p;
494 u_int event;
495
496 p = kn->kn_ptr.p_proc;
497 if (p == NULL) /* already activated, from attach filter */
498 return (0);
499
500 /* Mask off extra data. */
501 event = (u_int)hint & NOTE_PCTRLMASK;
502
503 /* If the user is interested in this event, record it. */
504 if (kn->kn_sfflags & event)
505 kn->kn_fflags |= event;
506
507 /* Process is gone, so flag the event as finished. */
508 if (event == NOTE_EXIT) {
509 kn->kn_flags |= EV_EOF | EV_ONESHOT;
510 kn->kn_ptr.p_proc = NULL;
511 if (kn->kn_fflags & NOTE_EXIT)
512 kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig);
513 if (kn->kn_fflags == 0)
514 kn->kn_flags |= EV_DROP;
515 return (1);
516 }
517
518 return (kn->kn_fflags != 0);
519 }
520
521 /*
522 * Called when the process forked. It mostly does the same as the
523 * knote(), activating all knotes registered to be activated when the
524 * process forked. Additionally, for each knote attached to the
525 * parent, check whether user wants to track the new process. If so
526 * attach a new knote to it, and immediately report an event with the
527 * child's pid.
528 */
529 void
530 knote_fork(struct knlist *list, int pid)
531 {
532 struct kqueue *kq;
533 struct knote *kn;
534 struct kevent kev;
535 int error;
536
537 MPASS(list != NULL);
538 KNL_ASSERT_LOCKED(list);
539 if (SLIST_EMPTY(&list->kl_list))
540 return;
541
542 memset(&kev, 0, sizeof(kev));
543 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
544 kq = kn->kn_kq;
545 KQ_LOCK(kq);
546 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) {
547 KQ_UNLOCK(kq);
548 continue;
549 }
550
551 /*
552 * The same as knote(), activate the event.
553 */
554 if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
555 if (kn->kn_fop->f_event(kn, NOTE_FORK))
556 KNOTE_ACTIVATE(kn, 1);
557 KQ_UNLOCK(kq);
558 continue;
559 }
560
561 /*
562 * The NOTE_TRACK case. In addition to the activation
563 * of the event, we need to register new events to
564 * track the child. Drop the locks in preparation for
565 * the call to kqueue_register().
566 */
567 kn_enter_flux(kn);
568 KQ_UNLOCK(kq);
569 list->kl_unlock(list->kl_lockarg);
570
571 /*
572 * Activate existing knote and register tracking knotes with
573 * new process.
574 *
575 * First register a knote to get just the child notice. This
576 * must be a separate note from a potential NOTE_EXIT
577 * notification since both NOTE_CHILD and NOTE_EXIT are defined
578 * to use the data field (in conflicting ways).
579 */
580 kev.ident = pid;
581 kev.filter = kn->kn_filter;
582 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT |
583 EV_FLAG2;
584 kev.fflags = kn->kn_sfflags;
585 kev.data = kn->kn_id; /* parent */
586 kev.udata = kn->kn_kevent.udata;/* preserve udata */
587 error = kqueue_register(kq, &kev, NULL, M_NOWAIT);
588 if (error)
589 kn->kn_fflags |= NOTE_TRACKERR;
590
591 /*
592 * Then register another knote to track other potential events
593 * from the new process.
594 */
595 kev.ident = pid;
596 kev.filter = kn->kn_filter;
597 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
598 kev.fflags = kn->kn_sfflags;
599 kev.data = kn->kn_id; /* parent */
600 kev.udata = kn->kn_kevent.udata;/* preserve udata */
601 error = kqueue_register(kq, &kev, NULL, M_NOWAIT);
602 if (error)
603 kn->kn_fflags |= NOTE_TRACKERR;
604 if (kn->kn_fop->f_event(kn, NOTE_FORK))
605 KNOTE_ACTIVATE(kn, 0);
606 list->kl_lock(list->kl_lockarg);
607 KQ_LOCK(kq);
608 kn_leave_flux(kn);
609 KQ_UNLOCK_FLUX(kq);
610 }
611 }
612
613 /*
614 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the
615 * interval timer support code.
616 */
617
618 #define NOTE_TIMER_PRECMASK \
619 (NOTE_SECONDS | NOTE_MSECONDS | NOTE_USECONDS | NOTE_NSECONDS)
620
621 static sbintime_t
622 timer2sbintime(int64_t data, int flags)
623 {
624 int64_t secs;
625
626 /*
627 * Macros for converting to the fractional second portion of an
628 * sbintime_t using 64bit multiplication to improve precision.
629 */
630 #define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32)
631 #define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32)
632 #define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32)
633 switch (flags & NOTE_TIMER_PRECMASK) {
634 case NOTE_SECONDS:
635 #ifdef __LP64__
636 if (data > (SBT_MAX / SBT_1S))
637 return (SBT_MAX);
638 #endif
639 return ((sbintime_t)data << 32);
640 case NOTE_MSECONDS: /* FALLTHROUGH */
641 case 0:
642 if (data >= 1000) {
643 secs = data / 1000;
644 #ifdef __LP64__
645 if (secs > (SBT_MAX / SBT_1S))
646 return (SBT_MAX);
647 #endif
648 return (secs << 32 | MS_TO_SBT(data % 1000));
649 }
650 return (MS_TO_SBT(data));
651 case NOTE_USECONDS:
652 if (data >= 1000000) {
653 secs = data / 1000000;
654 #ifdef __LP64__
655 if (secs > (SBT_MAX / SBT_1S))
656 return (SBT_MAX);
657 #endif
658 return (secs << 32 | US_TO_SBT(data % 1000000));
659 }
660 return (US_TO_SBT(data));
661 case NOTE_NSECONDS:
662 if (data >= 1000000000) {
663 secs = data / 1000000000;
664 #ifdef __LP64__
665 if (secs > (SBT_MAX / SBT_1S))
666 return (SBT_MAX);
667 #endif
668 return (secs << 32 | NS_TO_SBT(data % 1000000000));
669 }
670 return (NS_TO_SBT(data));
671 default:
672 break;
673 }
674 return (-1);
675 }
676
677 struct kq_timer_cb_data {
678 struct callout c;
679 struct proc *p;
680 struct knote *kn;
681 int cpuid;
682 int flags;
683 TAILQ_ENTRY(kq_timer_cb_data) link;
684 sbintime_t next; /* next timer event fires at */
685 sbintime_t to; /* precalculated timer period, 0 for abs */
686 };
687
688 #define KQ_TIMER_CB_ENQUEUED 0x01
689
690 static void
691 kqtimer_sched_callout(struct kq_timer_cb_data *kc)
692 {
693 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kc->kn,
694 kc->cpuid, C_ABSOLUTE);
695 }
696
697 void
698 kqtimer_proc_continue(struct proc *p)
699 {
700 struct kq_timer_cb_data *kc, *kc1;
701 struct bintime bt;
702 sbintime_t now;
703
704 PROC_LOCK_ASSERT(p, MA_OWNED);
705
706 getboottimebin(&bt);
707 now = bttosbt(bt);
708
709 TAILQ_FOREACH_SAFE(kc, &p->p_kqtim_stop, link, kc1) {
710 TAILQ_REMOVE(&p->p_kqtim_stop, kc, link);
711 kc->flags &= ~KQ_TIMER_CB_ENQUEUED;
712 if (kc->next <= now)
713 filt_timerexpire_l(kc->kn, true);
714 else
715 kqtimer_sched_callout(kc);
716 }
717 }
718
719 static void
720 filt_timerexpire_l(struct knote *kn, bool proc_locked)
721 {
722 struct kq_timer_cb_data *kc;
723 struct proc *p;
724 uint64_t delta;
725 sbintime_t now;
726
727 kc = kn->kn_ptr.p_v;
728
729 if ((kn->kn_flags & EV_ONESHOT) != 0 || kc->to == 0) {
730 kn->kn_data++;
731 KNOTE_ACTIVATE(kn, 0);
732 return;
733 }
734
735 now = sbinuptime();
736 if (now >= kc->next) {
737 delta = (now - kc->next) / kc->to;
738 if (delta == 0)
739 delta = 1;
740 kn->kn_data += delta;
741 kc->next += delta * kc->to;
742 if (now >= kc->next) /* overflow */
743 kc->next = now + kc->to;
744 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
745 }
746
747 /*
748 * Initial check for stopped kc->p is racy. It is fine to
749 * miss the set of the stop flags, at worst we would schedule
750 * one more callout. On the other hand, it is not fine to not
751 * schedule when we we missed clearing of the flags, we
752 * recheck them under the lock and observe consistent state.
753 */
754 p = kc->p;
755 if (P_SHOULDSTOP(p) || P_KILLED(p)) {
756 if (!proc_locked)
757 PROC_LOCK(p);
758 if (P_SHOULDSTOP(p) || P_KILLED(p)) {
759 if ((kc->flags & KQ_TIMER_CB_ENQUEUED) == 0) {
760 kc->flags |= KQ_TIMER_CB_ENQUEUED;
761 TAILQ_INSERT_TAIL(&p->p_kqtim_stop, kc, link);
762 }
763 if (!proc_locked)
764 PROC_UNLOCK(p);
765 return;
766 }
767 if (!proc_locked)
768 PROC_UNLOCK(p);
769 }
770 kqtimer_sched_callout(kc);
771 }
772
773 static void
774 filt_timerexpire(void *knx)
775 {
776 filt_timerexpire_l(knx, false);
777 }
778
779 /*
780 * data contains amount of time to sleep
781 */
782 static int
783 filt_timervalidate(struct knote *kn, sbintime_t *to)
784 {
785 struct bintime bt;
786 sbintime_t sbt;
787
788 if (kn->kn_sdata < 0)
789 return (EINVAL);
790 if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0)
791 kn->kn_sdata = 1;
792 /*
793 * The only fflags values supported are the timer unit
794 * (precision) and the absolute time indicator.
795 */
796 if ((kn->kn_sfflags & ~(NOTE_TIMER_PRECMASK | NOTE_ABSTIME)) != 0)
797 return (EINVAL);
798
799 *to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags);
800 if (*to < 0)
801 return (EINVAL);
802 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) {
803 getboottimebin(&bt);
804 sbt = bttosbt(bt);
805 *to = MAX(0, *to - sbt);
806 }
807 return (0);
808 }
809
810 static int
811 filt_timerattach(struct knote *kn)
812 {
813 struct kq_timer_cb_data *kc;
814 sbintime_t to;
815 int error;
816
817 to = -1;
818 error = filt_timervalidate(kn, &to);
819 if (error != 0)
820 return (error);
821 KASSERT(to > 0 || (kn->kn_flags & EV_ONESHOT) != 0 ||
822 (kn->kn_sfflags & NOTE_ABSTIME) != 0,
823 ("%s: periodic timer has a calculated zero timeout", __func__));
824 KASSERT(to >= 0,
825 ("%s: timer has a calculated negative timeout", __func__));
826
827 if (atomic_fetchadd_int(&kq_ncallouts, 1) + 1 > kq_calloutmax) {
828 atomic_subtract_int(&kq_ncallouts, 1);
829 return (ENOMEM);
830 }
831
832 if ((kn->kn_sfflags & NOTE_ABSTIME) == 0)
833 kn->kn_flags |= EV_CLEAR; /* automatically set */
834 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */
835 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK);
836 kc->kn = kn;
837 kc->p = curproc;
838 kc->cpuid = PCPU_GET(cpuid);
839 kc->flags = 0;
840 callout_init(&kc->c, 1);
841 filt_timerstart(kn, to);
842
843 return (0);
844 }
845
846 static void
847 filt_timerstart(struct knote *kn, sbintime_t to)
848 {
849 struct kq_timer_cb_data *kc;
850
851 kc = kn->kn_ptr.p_v;
852 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) {
853 kc->next = to;
854 kc->to = 0;
855 } else {
856 kc->next = to + sbinuptime();
857 kc->to = to;
858 }
859 kqtimer_sched_callout(kc);
860 }
861
862 static void
863 filt_timerdetach(struct knote *kn)
864 {
865 struct kq_timer_cb_data *kc;
866 unsigned int old __unused;
867 bool pending;
868
869 kc = kn->kn_ptr.p_v;
870 do {
871 callout_drain(&kc->c);
872
873 /*
874 * kqtimer_proc_continue() might have rescheduled this callout.
875 * Double-check, using the process mutex as an interlock.
876 */
877 PROC_LOCK(kc->p);
878 if ((kc->flags & KQ_TIMER_CB_ENQUEUED) != 0) {
879 kc->flags &= ~KQ_TIMER_CB_ENQUEUED;
880 TAILQ_REMOVE(&kc->p->p_kqtim_stop, kc, link);
881 }
882 pending = callout_pending(&kc->c);
883 PROC_UNLOCK(kc->p);
884 } while (pending);
885 free(kc, M_KQUEUE);
886 old = atomic_fetchadd_int(&kq_ncallouts, -1);
887 KASSERT(old > 0, ("Number of callouts cannot become negative"));
888 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */
889 }
890
891 static void
892 filt_timertouch(struct knote *kn, struct kevent *kev, u_long type)
893 {
894 struct kq_timer_cb_data *kc;
895 struct kqueue *kq;
896 sbintime_t to;
897 int error;
898
899 switch (type) {
900 case EVENT_REGISTER:
901 /* Handle re-added timers that update data/fflags */
902 if (kev->flags & EV_ADD) {
903 kc = kn->kn_ptr.p_v;
904
905 /* Drain any existing callout. */
906 callout_drain(&kc->c);
907
908 /* Throw away any existing undelivered record
909 * of the timer expiration. This is done under
910 * the presumption that if a process is
911 * re-adding this timer with new parameters,
912 * it is no longer interested in what may have
913 * happened under the old parameters. If it is
914 * interested, it can wait for the expiration,
915 * delete the old timer definition, and then
916 * add the new one.
917 *
918 * This has to be done while the kq is locked:
919 * - if enqueued, dequeue
920 * - make it no longer active
921 * - clear the count of expiration events
922 */
923 kq = kn->kn_kq;
924 KQ_LOCK(kq);
925 if (kn->kn_status & KN_QUEUED)
926 knote_dequeue(kn);
927
928 kn->kn_status &= ~KN_ACTIVE;
929 kn->kn_data = 0;
930 KQ_UNLOCK(kq);
931
932 /* Reschedule timer based on new data/fflags */
933 kn->kn_sfflags = kev->fflags;
934 kn->kn_sdata = kev->data;
935 error = filt_timervalidate(kn, &to);
936 if (error != 0) {
937 kn->kn_flags |= EV_ERROR;
938 kn->kn_data = error;
939 } else
940 filt_timerstart(kn, to);
941 }
942 break;
943
944 case EVENT_PROCESS:
945 *kev = kn->kn_kevent;
946 if (kn->kn_flags & EV_CLEAR) {
947 kn->kn_data = 0;
948 kn->kn_fflags = 0;
949 }
950 break;
951
952 default:
953 panic("filt_timertouch() - invalid type (%ld)", type);
954 break;
955 }
956 }
957
958 static int
959 filt_timer(struct knote *kn, long hint)
960 {
961
962 return (kn->kn_data != 0);
963 }
964
965 static int
966 filt_userattach(struct knote *kn)
967 {
968
969 /*
970 * EVFILT_USER knotes are not attached to anything in the kernel.
971 */
972 kn->kn_hook = NULL;
973 if (kn->kn_fflags & NOTE_TRIGGER)
974 kn->kn_hookid = 1;
975 else
976 kn->kn_hookid = 0;
977 return (0);
978 }
979
980 static void
981 filt_userdetach(__unused struct knote *kn)
982 {
983
984 /*
985 * EVFILT_USER knotes are not attached to anything in the kernel.
986 */
987 }
988
989 static int
990 filt_user(struct knote *kn, __unused long hint)
991 {
992
993 return (kn->kn_hookid);
994 }
995
996 static void
997 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
998 {
999 u_int ffctrl;
1000
1001 switch (type) {
1002 case EVENT_REGISTER:
1003 if (kev->fflags & NOTE_TRIGGER)
1004 kn->kn_hookid = 1;
1005
1006 ffctrl = kev->fflags & NOTE_FFCTRLMASK;
1007 kev->fflags &= NOTE_FFLAGSMASK;
1008 switch (ffctrl) {
1009 case NOTE_FFNOP:
1010 break;
1011
1012 case NOTE_FFAND:
1013 kn->kn_sfflags &= kev->fflags;
1014 break;
1015
1016 case NOTE_FFOR:
1017 kn->kn_sfflags |= kev->fflags;
1018 break;
1019
1020 case NOTE_FFCOPY:
1021 kn->kn_sfflags = kev->fflags;
1022 break;
1023
1024 default:
1025 /* XXX Return error? */
1026 break;
1027 }
1028 kn->kn_sdata = kev->data;
1029 if (kev->flags & EV_CLEAR) {
1030 kn->kn_hookid = 0;
1031 kn->kn_data = 0;
1032 kn->kn_fflags = 0;
1033 }
1034 break;
1035
1036 case EVENT_PROCESS:
1037 *kev = kn->kn_kevent;
1038 kev->fflags = kn->kn_sfflags;
1039 kev->data = kn->kn_sdata;
1040 if (kn->kn_flags & EV_CLEAR) {
1041 kn->kn_hookid = 0;
1042 kn->kn_data = 0;
1043 kn->kn_fflags = 0;
1044 }
1045 break;
1046
1047 default:
1048 panic("filt_usertouch() - invalid type (%ld)", type);
1049 break;
1050 }
1051 }
1052
1053 int
1054 sys_kqueue(struct thread *td, struct kqueue_args *uap)
1055 {
1056
1057 return (kern_kqueue(td, 0, NULL));
1058 }
1059
1060 static void
1061 kqueue_init(struct kqueue *kq)
1062 {
1063
1064 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK);
1065 TAILQ_INIT(&kq->kq_head);
1066 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
1067 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
1068 }
1069
1070 int
1071 kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps)
1072 {
1073 struct filedesc *fdp;
1074 struct kqueue *kq;
1075 struct file *fp;
1076 struct ucred *cred;
1077 int fd, error;
1078
1079 fdp = td->td_proc->p_fd;
1080 cred = td->td_ucred;
1081 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES)))
1082 return (ENOMEM);
1083
1084 error = falloc_caps(td, &fp, &fd, flags, fcaps);
1085 if (error != 0) {
1086 chgkqcnt(cred->cr_ruidinfo, -1, 0);
1087 return (error);
1088 }
1089
1090 /* An extra reference on `fp' has been held for us by falloc(). */
1091 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
1092 kqueue_init(kq);
1093 kq->kq_fdp = fdp;
1094 kq->kq_cred = crhold(cred);
1095
1096 FILEDESC_XLOCK(fdp);
1097 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
1098 FILEDESC_XUNLOCK(fdp);
1099
1100 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
1101 fdrop(fp, td);
1102
1103 td->td_retval[0] = fd;
1104 return (0);
1105 }
1106
1107 struct g_kevent_args {
1108 int fd;
1109 const void *changelist;
1110 int nchanges;
1111 void *eventlist;
1112 int nevents;
1113 const struct timespec *timeout;
1114 };
1115
1116 int
1117 sys_kevent(struct thread *td, struct kevent_args *uap)
1118 {
1119 struct kevent_copyops k_ops = {
1120 .arg = uap,
1121 .k_copyout = kevent_copyout,
1122 .k_copyin = kevent_copyin,
1123 .kevent_size = sizeof(struct kevent),
1124 };
1125 struct g_kevent_args gk_args = {
1126 .fd = uap->fd,
1127 .changelist = uap->changelist,
1128 .nchanges = uap->nchanges,
1129 .eventlist = uap->eventlist,
1130 .nevents = uap->nevents,
1131 .timeout = uap->timeout,
1132 };
1133
1134 return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent"));
1135 }
1136
1137 static int
1138 kern_kevent_generic(struct thread *td, struct g_kevent_args *uap,
1139 struct kevent_copyops *k_ops, const char *struct_name)
1140 {
1141 struct timespec ts, *tsp;
1142 #ifdef KTRACE
1143 struct kevent *eventlist = uap->eventlist;
1144 #endif
1145 int error;
1146
1147 if (uap->timeout != NULL) {
1148 error = copyin(uap->timeout, &ts, sizeof(ts));
1149 if (error)
1150 return (error);
1151 tsp = &ts;
1152 } else
1153 tsp = NULL;
1154
1155 #ifdef KTRACE
1156 if (KTRPOINT(td, KTR_STRUCT_ARRAY))
1157 ktrstructarray(struct_name, UIO_USERSPACE, uap->changelist,
1158 uap->nchanges, k_ops->kevent_size);
1159 #endif
1160
1161 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
1162 k_ops, tsp);
1163
1164 #ifdef KTRACE
1165 if (error == 0 && KTRPOINT(td, KTR_STRUCT_ARRAY))
1166 ktrstructarray(struct_name, UIO_USERSPACE, eventlist,
1167 td->td_retval[0], k_ops->kevent_size);
1168 #endif
1169
1170 return (error);
1171 }
1172
1173 /*
1174 * Copy 'count' items into the destination list pointed to by uap->eventlist.
1175 */
1176 static int
1177 kevent_copyout(void *arg, struct kevent *kevp, int count)
1178 {
1179 struct kevent_args *uap;
1180 int error;
1181
1182 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1183 uap = (struct kevent_args *)arg;
1184
1185 error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
1186 if (error == 0)
1187 uap->eventlist += count;
1188 return (error);
1189 }
1190
1191 /*
1192 * Copy 'count' items from the list pointed to by uap->changelist.
1193 */
1194 static int
1195 kevent_copyin(void *arg, struct kevent *kevp, int count)
1196 {
1197 struct kevent_args *uap;
1198 int error;
1199
1200 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1201 uap = (struct kevent_args *)arg;
1202
1203 error = copyin(uap->changelist, kevp, count * sizeof *kevp);
1204 if (error == 0)
1205 uap->changelist += count;
1206 return (error);
1207 }
1208
1209 #ifdef COMPAT_FREEBSD11
1210 static int
1211 kevent11_copyout(void *arg, struct kevent *kevp, int count)
1212 {
1213 struct freebsd11_kevent_args *uap;
1214 struct freebsd11_kevent kev11;
1215 int error, i;
1216
1217 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1218 uap = (struct freebsd11_kevent_args *)arg;
1219
1220 for (i = 0; i < count; i++) {
1221 kev11.ident = kevp->ident;
1222 kev11.filter = kevp->filter;
1223 kev11.flags = kevp->flags;
1224 kev11.fflags = kevp->fflags;
1225 kev11.data = kevp->data;
1226 kev11.udata = kevp->udata;
1227 error = copyout(&kev11, uap->eventlist, sizeof(kev11));
1228 if (error != 0)
1229 break;
1230 uap->eventlist++;
1231 kevp++;
1232 }
1233 return (error);
1234 }
1235
1236 /*
1237 * Copy 'count' items from the list pointed to by uap->changelist.
1238 */
1239 static int
1240 kevent11_copyin(void *arg, struct kevent *kevp, int count)
1241 {
1242 struct freebsd11_kevent_args *uap;
1243 struct freebsd11_kevent kev11;
1244 int error, i;
1245
1246 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1247 uap = (struct freebsd11_kevent_args *)arg;
1248
1249 for (i = 0; i < count; i++) {
1250 error = copyin(uap->changelist, &kev11, sizeof(kev11));
1251 if (error != 0)
1252 break;
1253 kevp->ident = kev11.ident;
1254 kevp->filter = kev11.filter;
1255 kevp->flags = kev11.flags;
1256 kevp->fflags = kev11.fflags;
1257 kevp->data = (uintptr_t)kev11.data;
1258 kevp->udata = kev11.udata;
1259 bzero(&kevp->ext, sizeof(kevp->ext));
1260 uap->changelist++;
1261 kevp++;
1262 }
1263 return (error);
1264 }
1265
1266 int
1267 freebsd11_kevent(struct thread *td, struct freebsd11_kevent_args *uap)
1268 {
1269 struct kevent_copyops k_ops = {
1270 .arg = uap,
1271 .k_copyout = kevent11_copyout,
1272 .k_copyin = kevent11_copyin,
1273 .kevent_size = sizeof(struct freebsd11_kevent),
1274 };
1275 struct g_kevent_args gk_args = {
1276 .fd = uap->fd,
1277 .changelist = uap->changelist,
1278 .nchanges = uap->nchanges,
1279 .eventlist = uap->eventlist,
1280 .nevents = uap->nevents,
1281 .timeout = uap->timeout,
1282 };
1283
1284 return (kern_kevent_generic(td, &gk_args, &k_ops, "freebsd11_kevent"));
1285 }
1286 #endif
1287
1288 int
1289 kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
1290 struct kevent_copyops *k_ops, const struct timespec *timeout)
1291 {
1292 cap_rights_t rights;
1293 struct file *fp;
1294 int error;
1295
1296 cap_rights_init_zero(&rights);
1297 if (nchanges > 0)
1298 cap_rights_set_one(&rights, CAP_KQUEUE_CHANGE);
1299 if (nevents > 0)
1300 cap_rights_set_one(&rights, CAP_KQUEUE_EVENT);
1301 error = fget(td, fd, &rights, &fp);
1302 if (error != 0)
1303 return (error);
1304
1305 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout);
1306 fdrop(fp, td);
1307
1308 return (error);
1309 }
1310
1311 static int
1312 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents,
1313 struct kevent_copyops *k_ops, const struct timespec *timeout)
1314 {
1315 struct kevent keva[KQ_NEVENTS];
1316 struct kevent *kevp, *changes;
1317 int i, n, nerrors, error;
1318
1319 if (nchanges < 0)
1320 return (EINVAL);
1321
1322 nerrors = 0;
1323 while (nchanges > 0) {
1324 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
1325 error = k_ops->k_copyin(k_ops->arg, keva, n);
1326 if (error)
1327 return (error);
1328 changes = keva;
1329 for (i = 0; i < n; i++) {
1330 kevp = &changes[i];
1331 if (!kevp->filter)
1332 continue;
1333 kevp->flags &= ~EV_SYSFLAGS;
1334 error = kqueue_register(kq, kevp, td, M_WAITOK);
1335 if (error || (kevp->flags & EV_RECEIPT)) {
1336 if (nevents == 0)
1337 return (error);
1338 kevp->flags = EV_ERROR;
1339 kevp->data = error;
1340 (void)k_ops->k_copyout(k_ops->arg, kevp, 1);
1341 nevents--;
1342 nerrors++;
1343 }
1344 }
1345 nchanges -= n;
1346 }
1347 if (nerrors) {
1348 td->td_retval[0] = nerrors;
1349 return (0);
1350 }
1351
1352 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td));
1353 }
1354
1355 int
1356 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents,
1357 struct kevent_copyops *k_ops, const struct timespec *timeout)
1358 {
1359 struct kqueue *kq;
1360 int error;
1361
1362 error = kqueue_acquire(fp, &kq);
1363 if (error != 0)
1364 return (error);
1365 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout);
1366 kqueue_release(kq, 0);
1367 return (error);
1368 }
1369
1370 /*
1371 * Performs a kevent() call on a temporarily created kqueue. This can be
1372 * used to perform one-shot polling, similar to poll() and select().
1373 */
1374 int
1375 kern_kevent_anonymous(struct thread *td, int nevents,
1376 struct kevent_copyops *k_ops)
1377 {
1378 struct kqueue kq = {};
1379 int error;
1380
1381 kqueue_init(&kq);
1382 kq.kq_refcnt = 1;
1383 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL);
1384 kqueue_drain(&kq, td);
1385 kqueue_destroy(&kq);
1386 return (error);
1387 }
1388
1389 int
1390 kqueue_add_filteropts(int filt, struct filterops *filtops)
1391 {
1392 int error;
1393
1394 error = 0;
1395 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
1396 printf(
1397 "trying to add a filterop that is out of range: %d is beyond %d\n",
1398 ~filt, EVFILT_SYSCOUNT);
1399 return EINVAL;
1400 }
1401 mtx_lock(&filterops_lock);
1402 if (sysfilt_ops[~filt].for_fop != &null_filtops &&
1403 sysfilt_ops[~filt].for_fop != NULL)
1404 error = EEXIST;
1405 else {
1406 sysfilt_ops[~filt].for_fop = filtops;
1407 sysfilt_ops[~filt].for_refcnt = 0;
1408 }
1409 mtx_unlock(&filterops_lock);
1410
1411 return (error);
1412 }
1413
1414 int
1415 kqueue_del_filteropts(int filt)
1416 {
1417 int error;
1418
1419 error = 0;
1420 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1421 return EINVAL;
1422
1423 mtx_lock(&filterops_lock);
1424 if (sysfilt_ops[~filt].for_fop == &null_filtops ||
1425 sysfilt_ops[~filt].for_fop == NULL)
1426 error = EINVAL;
1427 else if (sysfilt_ops[~filt].for_refcnt != 0)
1428 error = EBUSY;
1429 else {
1430 sysfilt_ops[~filt].for_fop = &null_filtops;
1431 sysfilt_ops[~filt].for_refcnt = 0;
1432 }
1433 mtx_unlock(&filterops_lock);
1434
1435 return error;
1436 }
1437
1438 static struct filterops *
1439 kqueue_fo_find(int filt)
1440 {
1441
1442 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1443 return NULL;
1444
1445 if (sysfilt_ops[~filt].for_nolock)
1446 return sysfilt_ops[~filt].for_fop;
1447
1448 mtx_lock(&filterops_lock);
1449 sysfilt_ops[~filt].for_refcnt++;
1450 if (sysfilt_ops[~filt].for_fop == NULL)
1451 sysfilt_ops[~filt].for_fop = &null_filtops;
1452 mtx_unlock(&filterops_lock);
1453
1454 return sysfilt_ops[~filt].for_fop;
1455 }
1456
1457 static void
1458 kqueue_fo_release(int filt)
1459 {
1460
1461 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1462 return;
1463
1464 if (sysfilt_ops[~filt].for_nolock)
1465 return;
1466
1467 mtx_lock(&filterops_lock);
1468 KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
1469 ("filter object refcount not valid on release"));
1470 sysfilt_ops[~filt].for_refcnt--;
1471 mtx_unlock(&filterops_lock);
1472 }
1473
1474 /*
1475 * A ref to kq (obtained via kqueue_acquire) must be held.
1476 */
1477 static int
1478 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td,
1479 int mflag)
1480 {
1481 struct filterops *fops;
1482 struct file *fp;
1483 struct knote *kn, *tkn;
1484 struct knlist *knl;
1485 int error, filt, event;
1486 int haskqglobal, filedesc_unlock;
1487
1488 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE))
1489 return (EINVAL);
1490
1491 fp = NULL;
1492 kn = NULL;
1493 knl = NULL;
1494 error = 0;
1495 haskqglobal = 0;
1496 filedesc_unlock = 0;
1497
1498 filt = kev->filter;
1499 fops = kqueue_fo_find(filt);
1500 if (fops == NULL)
1501 return EINVAL;
1502
1503 if (kev->flags & EV_ADD) {
1504 /* Reject an invalid flag pair early */
1505 if (kev->flags & EV_KEEPUDATA) {
1506 tkn = NULL;
1507 error = EINVAL;
1508 goto done;
1509 }
1510
1511 /*
1512 * Prevent waiting with locks. Non-sleepable
1513 * allocation failures are handled in the loop, only
1514 * if the spare knote appears to be actually required.
1515 */
1516 tkn = knote_alloc(mflag);
1517 } else {
1518 tkn = NULL;
1519 }
1520
1521 findkn:
1522 if (fops->f_isfd) {
1523 KASSERT(td != NULL, ("td is NULL"));
1524 if (kev->ident > INT_MAX)
1525 error = EBADF;
1526 else
1527 error = fget(td, kev->ident, &cap_event_rights, &fp);
1528 if (error)
1529 goto done;
1530
1531 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
1532 kev->ident, M_NOWAIT) != 0) {
1533 /* try again */
1534 fdrop(fp, td);
1535 fp = NULL;
1536 error = kqueue_expand(kq, fops, kev->ident, mflag);
1537 if (error)
1538 goto done;
1539 goto findkn;
1540 }
1541
1542 if (fp->f_type == DTYPE_KQUEUE) {
1543 /*
1544 * If we add some intelligence about what we are doing,
1545 * we should be able to support events on ourselves.
1546 * We need to know when we are doing this to prevent
1547 * getting both the knlist lock and the kq lock since
1548 * they are the same thing.
1549 */
1550 if (fp->f_data == kq) {
1551 error = EINVAL;
1552 goto done;
1553 }
1554
1555 /*
1556 * Pre-lock the filedesc before the global
1557 * lock mutex, see the comment in
1558 * kqueue_close().
1559 */
1560 FILEDESC_XLOCK(td->td_proc->p_fd);
1561 filedesc_unlock = 1;
1562 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1563 }
1564
1565 KQ_LOCK(kq);
1566 if (kev->ident < kq->kq_knlistsize) {
1567 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
1568 if (kev->filter == kn->kn_filter)
1569 break;
1570 }
1571 } else {
1572 if ((kev->flags & EV_ADD) == EV_ADD) {
1573 error = kqueue_expand(kq, fops, kev->ident, mflag);
1574 if (error != 0)
1575 goto done;
1576 }
1577
1578 KQ_LOCK(kq);
1579
1580 /*
1581 * If possible, find an existing knote to use for this kevent.
1582 */
1583 if (kev->filter == EVFILT_PROC &&
1584 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) {
1585 /* This is an internal creation of a process tracking
1586 * note. Don't attempt to coalesce this with an
1587 * existing note.
1588 */
1589 ;
1590 } else if (kq->kq_knhashmask != 0) {
1591 struct klist *list;
1592
1593 list = &kq->kq_knhash[
1594 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
1595 SLIST_FOREACH(kn, list, kn_link)
1596 if (kev->ident == kn->kn_id &&
1597 kev->filter == kn->kn_filter)
1598 break;
1599 }
1600 }
1601
1602 /* knote is in the process of changing, wait for it to stabilize. */
1603 if (kn != NULL && kn_in_flux(kn)) {
1604 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1605 if (filedesc_unlock) {
1606 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1607 filedesc_unlock = 0;
1608 }
1609 kq->kq_state |= KQ_FLUXWAIT;
1610 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
1611 if (fp != NULL) {
1612 fdrop(fp, td);
1613 fp = NULL;
1614 }
1615 goto findkn;
1616 }
1617
1618 /*
1619 * kn now contains the matching knote, or NULL if no match
1620 */
1621 if (kn == NULL) {
1622 if (kev->flags & EV_ADD) {
1623 kn = tkn;
1624 tkn = NULL;
1625 if (kn == NULL) {
1626 KQ_UNLOCK(kq);
1627 error = ENOMEM;
1628 goto done;
1629 }
1630 kn->kn_fp = fp;
1631 kn->kn_kq = kq;
1632 kn->kn_fop = fops;
1633 /*
1634 * apply reference counts to knote structure, and
1635 * do not release it at the end of this routine.
1636 */
1637 fops = NULL;
1638 fp = NULL;
1639
1640 kn->kn_sfflags = kev->fflags;
1641 kn->kn_sdata = kev->data;
1642 kev->fflags = 0;
1643 kev->data = 0;
1644 kn->kn_kevent = *kev;
1645 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
1646 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT);
1647 kn->kn_status = KN_DETACHED;
1648 if ((kev->flags & EV_DISABLE) != 0)
1649 kn->kn_status |= KN_DISABLED;
1650 kn_enter_flux(kn);
1651
1652 error = knote_attach(kn, kq);
1653 KQ_UNLOCK(kq);
1654 if (error != 0) {
1655 tkn = kn;
1656 goto done;
1657 }
1658
1659 if ((error = kn->kn_fop->f_attach(kn)) != 0) {
1660 knote_drop_detached(kn, td);
1661 goto done;
1662 }
1663 knl = kn_list_lock(kn);
1664 goto done_ev_add;
1665 } else {
1666 /* No matching knote and the EV_ADD flag is not set. */
1667 KQ_UNLOCK(kq);
1668 error = ENOENT;
1669 goto done;
1670 }
1671 }
1672
1673 if (kev->flags & EV_DELETE) {
1674 kn_enter_flux(kn);
1675 KQ_UNLOCK(kq);
1676 knote_drop(kn, td);
1677 goto done;
1678 }
1679
1680 if (kev->flags & EV_FORCEONESHOT) {
1681 kn->kn_flags |= EV_ONESHOT;
1682 KNOTE_ACTIVATE(kn, 1);
1683 }
1684
1685 if ((kev->flags & EV_ENABLE) != 0)
1686 kn->kn_status &= ~KN_DISABLED;
1687 else if ((kev->flags & EV_DISABLE) != 0)
1688 kn->kn_status |= KN_DISABLED;
1689
1690 /*
1691 * The user may change some filter values after the initial EV_ADD,
1692 * but doing so will not reset any filter which has already been
1693 * triggered.
1694 */
1695 kn->kn_status |= KN_SCAN;
1696 kn_enter_flux(kn);
1697 KQ_UNLOCK(kq);
1698 knl = kn_list_lock(kn);
1699 if ((kev->flags & EV_KEEPUDATA) == 0)
1700 kn->kn_kevent.udata = kev->udata;
1701 if (!fops->f_isfd && fops->f_touch != NULL) {
1702 fops->f_touch(kn, kev, EVENT_REGISTER);
1703 } else {
1704 kn->kn_sfflags = kev->fflags;
1705 kn->kn_sdata = kev->data;
1706 }
1707
1708 done_ev_add:
1709 /*
1710 * We can get here with kn->kn_knlist == NULL. This can happen when
1711 * the initial attach event decides that the event is "completed"
1712 * already, e.g., filt_procattach() is called on a zombie process. It
1713 * will call filt_proc() which will remove it from the list, and NULL
1714 * kn_knlist.
1715 *
1716 * KN_DISABLED will be stable while the knote is in flux, so the
1717 * unlocked read will not race with an update.
1718 */
1719 if ((kn->kn_status & KN_DISABLED) == 0)
1720 event = kn->kn_fop->f_event(kn, 0);
1721 else
1722 event = 0;
1723
1724 KQ_LOCK(kq);
1725 if (event)
1726 kn->kn_status |= KN_ACTIVE;
1727 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) ==
1728 KN_ACTIVE)
1729 knote_enqueue(kn);
1730 kn->kn_status &= ~KN_SCAN;
1731 kn_leave_flux(kn);
1732 kn_list_unlock(knl);
1733 KQ_UNLOCK_FLUX(kq);
1734
1735 done:
1736 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1737 if (filedesc_unlock)
1738 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1739 if (fp != NULL)
1740 fdrop(fp, td);
1741 knote_free(tkn);
1742 if (fops != NULL)
1743 kqueue_fo_release(filt);
1744 return (error);
1745 }
1746
1747 static int
1748 kqueue_acquire(struct file *fp, struct kqueue **kqp)
1749 {
1750 int error;
1751 struct kqueue *kq;
1752
1753 error = 0;
1754
1755 kq = fp->f_data;
1756 if (fp->f_type != DTYPE_KQUEUE || kq == NULL)
1757 return (EBADF);
1758 *kqp = kq;
1759 KQ_LOCK(kq);
1760 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
1761 KQ_UNLOCK(kq);
1762 return (EBADF);
1763 }
1764 kq->kq_refcnt++;
1765 KQ_UNLOCK(kq);
1766
1767 return error;
1768 }
1769
1770 static void
1771 kqueue_release(struct kqueue *kq, int locked)
1772 {
1773 if (locked)
1774 KQ_OWNED(kq);
1775 else
1776 KQ_LOCK(kq);
1777 kq->kq_refcnt--;
1778 if (kq->kq_refcnt == 1)
1779 wakeup(&kq->kq_refcnt);
1780 if (!locked)
1781 KQ_UNLOCK(kq);
1782 }
1783
1784 static void
1785 ast_kqueue(struct thread *td, int tda __unused)
1786 {
1787 taskqueue_quiesce(taskqueue_kqueue_ctx);
1788 }
1789
1790 static void
1791 kqueue_schedtask(struct kqueue *kq)
1792 {
1793 KQ_OWNED(kq);
1794 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
1795 ("scheduling kqueue task while draining"));
1796
1797 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
1798 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task);
1799 kq->kq_state |= KQ_TASKSCHED;
1800 ast_sched(curthread, TDA_KQUEUE);
1801 }
1802 }
1803
1804 /*
1805 * Expand the kq to make sure we have storage for fops/ident pair.
1806 *
1807 * Return 0 on success (or no work necessary), return errno on failure.
1808 */
1809 static int
1810 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident,
1811 int mflag)
1812 {
1813 struct klist *list, *tmp_knhash, *to_free;
1814 u_long tmp_knhashmask;
1815 int error, fd, size;
1816
1817 KQ_NOTOWNED(kq);
1818
1819 error = 0;
1820 to_free = NULL;
1821 if (fops->f_isfd) {
1822 fd = ident;
1823 if (kq->kq_knlistsize <= fd) {
1824 size = kq->kq_knlistsize;
1825 while (size <= fd)
1826 size += KQEXTENT;
1827 list = malloc(size * sizeof(*list), M_KQUEUE, mflag);
1828 if (list == NULL)
1829 return ENOMEM;
1830 KQ_LOCK(kq);
1831 if ((kq->kq_state & KQ_CLOSING) != 0) {
1832 to_free = list;
1833 error = EBADF;
1834 } else if (kq->kq_knlistsize > fd) {
1835 to_free = list;
1836 } else {
1837 if (kq->kq_knlist != NULL) {
1838 bcopy(kq->kq_knlist, list,
1839 kq->kq_knlistsize * sizeof(*list));
1840 to_free = kq->kq_knlist;
1841 kq->kq_knlist = NULL;
1842 }
1843 bzero((caddr_t)list +
1844 kq->kq_knlistsize * sizeof(*list),
1845 (size - kq->kq_knlistsize) * sizeof(*list));
1846 kq->kq_knlistsize = size;
1847 kq->kq_knlist = list;
1848 }
1849 KQ_UNLOCK(kq);
1850 }
1851 } else {
1852 if (kq->kq_knhashmask == 0) {
1853 tmp_knhash = hashinit_flags(KN_HASHSIZE, M_KQUEUE,
1854 &tmp_knhashmask, (mflag & M_WAITOK) != 0 ?
1855 HASH_WAITOK : HASH_NOWAIT);
1856 if (tmp_knhash == NULL)
1857 return (ENOMEM);
1858 KQ_LOCK(kq);
1859 if ((kq->kq_state & KQ_CLOSING) != 0) {
1860 to_free = tmp_knhash;
1861 error = EBADF;
1862 } else if (kq->kq_knhashmask == 0) {
1863 kq->kq_knhash = tmp_knhash;
1864 kq->kq_knhashmask = tmp_knhashmask;
1865 } else {
1866 to_free = tmp_knhash;
1867 }
1868 KQ_UNLOCK(kq);
1869 }
1870 }
1871 free(to_free, M_KQUEUE);
1872
1873 KQ_NOTOWNED(kq);
1874 return (error);
1875 }
1876
1877 static void
1878 kqueue_task(void *arg, int pending)
1879 {
1880 struct kqueue *kq;
1881 int haskqglobal;
1882
1883 haskqglobal = 0;
1884 kq = arg;
1885
1886 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1887 KQ_LOCK(kq);
1888
1889 KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
1890
1891 kq->kq_state &= ~KQ_TASKSCHED;
1892 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
1893 wakeup(&kq->kq_state);
1894 }
1895 KQ_UNLOCK(kq);
1896 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1897 }
1898
1899 /*
1900 * Scan, update kn_data (if not ONESHOT), and copyout triggered events.
1901 * We treat KN_MARKER knotes as if they are in flux.
1902 */
1903 static int
1904 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
1905 const struct timespec *tsp, struct kevent *keva, struct thread *td)
1906 {
1907 struct kevent *kevp;
1908 struct knote *kn, *marker;
1909 struct knlist *knl;
1910 sbintime_t asbt, rsbt;
1911 int count, error, haskqglobal, influx, nkev, touch;
1912
1913 count = maxevents;
1914 nkev = 0;
1915 error = 0;
1916 haskqglobal = 0;
1917
1918 if (maxevents == 0)
1919 goto done_nl;
1920 if (maxevents < 0) {
1921 error = EINVAL;
1922 goto done_nl;
1923 }
1924
1925 rsbt = 0;
1926 if (tsp != NULL) {
1927 if (!timespecvalid_interval(tsp)) {
1928 error = EINVAL;
1929 goto done_nl;
1930 }
1931 if (timespecisset(tsp)) {
1932 if (tsp->tv_sec <= INT32_MAX) {
1933 rsbt = tstosbt(*tsp);
1934 if (TIMESEL(&asbt, rsbt))
1935 asbt += tc_tick_sbt;
1936 if (asbt <= SBT_MAX - rsbt)
1937 asbt += rsbt;
1938 else
1939 asbt = 0;
1940 rsbt >>= tc_precexp;
1941 } else
1942 asbt = 0;
1943 } else
1944 asbt = -1;
1945 } else
1946 asbt = 0;
1947 marker = knote_alloc(M_WAITOK);
1948 marker->kn_status = KN_MARKER;
1949 KQ_LOCK(kq);
1950
1951 retry:
1952 kevp = keva;
1953 if (kq->kq_count == 0) {
1954 if (asbt == -1) {
1955 error = EWOULDBLOCK;
1956 } else {
1957 kq->kq_state |= KQ_SLEEP;
1958 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH,
1959 "kqread", asbt, rsbt, C_ABSOLUTE);
1960 }
1961 if (error == 0)
1962 goto retry;
1963 /* don't restart after signals... */
1964 if (error == ERESTART)
1965 error = EINTR;
1966 else if (error == EWOULDBLOCK)
1967 error = 0;
1968 goto done;
1969 }
1970
1971 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
1972 influx = 0;
1973 while (count) {
1974 KQ_OWNED(kq);
1975 kn = TAILQ_FIRST(&kq->kq_head);
1976
1977 if ((kn->kn_status == KN_MARKER && kn != marker) ||
1978 kn_in_flux(kn)) {
1979 if (influx) {
1980 influx = 0;
1981 KQ_FLUX_WAKEUP(kq);
1982 }
1983 kq->kq_state |= KQ_FLUXWAIT;
1984 error = msleep(kq, &kq->kq_lock, PSOCK,
1985 "kqflxwt", 0);
1986 continue;
1987 }
1988
1989 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
1990 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
1991 kn->kn_status &= ~KN_QUEUED;
1992 kq->kq_count--;
1993 continue;
1994 }
1995 if (kn == marker) {
1996 KQ_FLUX_WAKEUP(kq);
1997 if (count == maxevents)
1998 goto retry;
1999 goto done;
2000 }
2001 KASSERT(!kn_in_flux(kn),
2002 ("knote %p is unexpectedly in flux", kn));
2003
2004 if ((kn->kn_flags & EV_DROP) == EV_DROP) {
2005 kn->kn_status &= ~KN_QUEUED;
2006 kn_enter_flux(kn);
2007 kq->kq_count--;
2008 KQ_UNLOCK(kq);
2009 /*
2010 * We don't need to lock the list since we've
2011 * marked it as in flux.
2012 */
2013 knote_drop(kn, td);
2014 KQ_LOCK(kq);
2015 continue;
2016 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
2017 kn->kn_status &= ~KN_QUEUED;
2018 kn_enter_flux(kn);
2019 kq->kq_count--;
2020 KQ_UNLOCK(kq);
2021 /*
2022 * We don't need to lock the list since we've
2023 * marked the knote as being in flux.
2024 */
2025 *kevp = kn->kn_kevent;
2026 knote_drop(kn, td);
2027 KQ_LOCK(kq);
2028 kn = NULL;
2029 } else {
2030 kn->kn_status |= KN_SCAN;
2031 kn_enter_flux(kn);
2032 KQ_UNLOCK(kq);
2033 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
2034 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
2035 knl = kn_list_lock(kn);
2036 if (kn->kn_fop->f_event(kn, 0) == 0) {
2037 KQ_LOCK(kq);
2038 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
2039 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE |
2040 KN_SCAN);
2041 kn_leave_flux(kn);
2042 kq->kq_count--;
2043 kn_list_unlock(knl);
2044 influx = 1;
2045 continue;
2046 }
2047 touch = (!kn->kn_fop->f_isfd &&
2048 kn->kn_fop->f_touch != NULL);
2049 if (touch)
2050 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS);
2051 else
2052 *kevp = kn->kn_kevent;
2053 KQ_LOCK(kq);
2054 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
2055 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
2056 /*
2057 * Manually clear knotes who weren't
2058 * 'touch'ed.
2059 */
2060 if (touch == 0 && kn->kn_flags & EV_CLEAR) {
2061 kn->kn_data = 0;
2062 kn->kn_fflags = 0;
2063 }
2064 if (kn->kn_flags & EV_DISPATCH)
2065 kn->kn_status |= KN_DISABLED;
2066 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
2067 kq->kq_count--;
2068 } else
2069 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
2070
2071 kn->kn_status &= ~KN_SCAN;
2072 kn_leave_flux(kn);
2073 kn_list_unlock(knl);
2074 influx = 1;
2075 }
2076
2077 /* we are returning a copy to the user */
2078 kevp++;
2079 nkev++;
2080 count--;
2081
2082 if (nkev == KQ_NEVENTS) {
2083 influx = 0;
2084 KQ_UNLOCK_FLUX(kq);
2085 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
2086 nkev = 0;
2087 kevp = keva;
2088 KQ_LOCK(kq);
2089 if (error)
2090 break;
2091 }
2092 }
2093 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
2094 done:
2095 KQ_OWNED(kq);
2096 KQ_UNLOCK_FLUX(kq);
2097 knote_free(marker);
2098 done_nl:
2099 KQ_NOTOWNED(kq);
2100 if (nkev != 0)
2101 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
2102 td->td_retval[0] = maxevents - count;
2103 return (error);
2104 }
2105
2106 /*ARGSUSED*/
2107 static int
2108 kqueue_ioctl(struct file *fp, u_long cmd, void *data,
2109 struct ucred *active_cred, struct thread *td)
2110 {
2111 /*
2112 * Enabling sigio causes two major problems:
2113 * 1) infinite recursion:
2114 * Synopsys: kevent is being used to track signals and have FIOASYNC
2115 * set. On receipt of a signal this will cause a kqueue to recurse
2116 * into itself over and over. Sending the sigio causes the kqueue
2117 * to become ready, which in turn posts sigio again, forever.
2118 * Solution: this can be solved by setting a flag in the kqueue that
2119 * we have a SIGIO in progress.
2120 * 2) locking problems:
2121 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
2122 * us above the proc and pgrp locks.
2123 * Solution: Post a signal using an async mechanism, being sure to
2124 * record a generation count in the delivery so that we do not deliver
2125 * a signal to the wrong process.
2126 *
2127 * Note, these two mechanisms are somewhat mutually exclusive!
2128 */
2129 #if 0
2130 struct kqueue *kq;
2131
2132 kq = fp->f_data;
2133 switch (cmd) {
2134 case FIOASYNC:
2135 if (*(int *)data) {
2136 kq->kq_state |= KQ_ASYNC;
2137 } else {
2138 kq->kq_state &= ~KQ_ASYNC;
2139 }
2140 return (0);
2141
2142 case FIOSETOWN:
2143 return (fsetown(*(int *)data, &kq->kq_sigio));
2144
2145 case FIOGETOWN:
2146 *(int *)data = fgetown(&kq->kq_sigio);
2147 return (0);
2148 }
2149 #endif
2150
2151 return (ENOTTY);
2152 }
2153
2154 /*ARGSUSED*/
2155 static int
2156 kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
2157 struct thread *td)
2158 {
2159 struct kqueue *kq;
2160 int revents = 0;
2161 int error;
2162
2163 if ((error = kqueue_acquire(fp, &kq)))
2164 return POLLERR;
2165
2166 KQ_LOCK(kq);
2167 if (events & (POLLIN | POLLRDNORM)) {
2168 if (kq->kq_count) {
2169 revents |= events & (POLLIN | POLLRDNORM);
2170 } else {
2171 selrecord(td, &kq->kq_sel);
2172 if (SEL_WAITING(&kq->kq_sel))
2173 kq->kq_state |= KQ_SEL;
2174 }
2175 }
2176 kqueue_release(kq, 1);
2177 KQ_UNLOCK(kq);
2178 return (revents);
2179 }
2180
2181 /*ARGSUSED*/
2182 static int
2183 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred)
2184 {
2185
2186 bzero((void *)st, sizeof *st);
2187 /*
2188 * We no longer return kq_count because the unlocked value is useless.
2189 * If you spent all this time getting the count, why not spend your
2190 * syscall better by calling kevent?
2191 *
2192 * XXX - This is needed for libc_r.
2193 */
2194 st->st_mode = S_IFIFO;
2195 return (0);
2196 }
2197
2198 static void
2199 kqueue_drain(struct kqueue *kq, struct thread *td)
2200 {
2201 struct knote *kn;
2202 int i;
2203
2204 KQ_LOCK(kq);
2205
2206 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
2207 ("kqueue already closing"));
2208 kq->kq_state |= KQ_CLOSING;
2209 if (kq->kq_refcnt > 1)
2210 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
2211
2212 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
2213
2214 KASSERT(knlist_empty(&kq->kq_sel.si_note),
2215 ("kqueue's knlist not empty"));
2216
2217 for (i = 0; i < kq->kq_knlistsize; i++) {
2218 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
2219 if (kn_in_flux(kn)) {
2220 kq->kq_state |= KQ_FLUXWAIT;
2221 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
2222 continue;
2223 }
2224 kn_enter_flux(kn);
2225 KQ_UNLOCK(kq);
2226 knote_drop(kn, td);
2227 KQ_LOCK(kq);
2228 }
2229 }
2230 if (kq->kq_knhashmask != 0) {
2231 for (i = 0; i <= kq->kq_knhashmask; i++) {
2232 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
2233 if (kn_in_flux(kn)) {
2234 kq->kq_state |= KQ_FLUXWAIT;
2235 msleep(kq, &kq->kq_lock, PSOCK,
2236 "kqclo2", 0);
2237 continue;
2238 }
2239 kn_enter_flux(kn);
2240 KQ_UNLOCK(kq);
2241 knote_drop(kn, td);
2242 KQ_LOCK(kq);
2243 }
2244 }
2245 }
2246
2247 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
2248 kq->kq_state |= KQ_TASKDRAIN;
2249 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
2250 }
2251
2252 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
2253 selwakeuppri(&kq->kq_sel, PSOCK);
2254 if (!SEL_WAITING(&kq->kq_sel))
2255 kq->kq_state &= ~KQ_SEL;
2256 }
2257
2258 KQ_UNLOCK(kq);
2259 }
2260
2261 static void
2262 kqueue_destroy(struct kqueue *kq)
2263 {
2264
2265 KASSERT(kq->kq_fdp == NULL,
2266 ("kqueue still attached to a file descriptor"));
2267 seldrain(&kq->kq_sel);
2268 knlist_destroy(&kq->kq_sel.si_note);
2269 mtx_destroy(&kq->kq_lock);
2270
2271 if (kq->kq_knhash != NULL)
2272 free(kq->kq_knhash, M_KQUEUE);
2273 if (kq->kq_knlist != NULL)
2274 free(kq->kq_knlist, M_KQUEUE);
2275
2276 funsetown(&kq->kq_sigio);
2277 }
2278
2279 /*ARGSUSED*/
2280 static int
2281 kqueue_close(struct file *fp, struct thread *td)
2282 {
2283 struct kqueue *kq = fp->f_data;
2284 struct filedesc *fdp;
2285 int error;
2286 int filedesc_unlock;
2287
2288 if ((error = kqueue_acquire(fp, &kq)))
2289 return error;
2290 kqueue_drain(kq, td);
2291
2292 /*
2293 * We could be called due to the knote_drop() doing fdrop(),
2294 * called from kqueue_register(). In this case the global
2295 * lock is owned, and filedesc sx is locked before, to not
2296 * take the sleepable lock after non-sleepable.
2297 */
2298 fdp = kq->kq_fdp;
2299 kq->kq_fdp = NULL;
2300 if (!sx_xlocked(FILEDESC_LOCK(fdp))) {
2301 FILEDESC_XLOCK(fdp);
2302 filedesc_unlock = 1;
2303 } else
2304 filedesc_unlock = 0;
2305 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list);
2306 if (filedesc_unlock)
2307 FILEDESC_XUNLOCK(fdp);
2308
2309 kqueue_destroy(kq);
2310 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0);
2311 crfree(kq->kq_cred);
2312 free(kq, M_KQUEUE);
2313 fp->f_data = NULL;
2314
2315 return (0);
2316 }
2317
2318 static int
2319 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
2320 {
2321 struct kqueue *kq = fp->f_data;
2322
2323 kif->kf_type = KF_TYPE_KQUEUE;
2324 kif->kf_un.kf_kqueue.kf_kqueue_addr = (uintptr_t)kq;
2325 kif->kf_un.kf_kqueue.kf_kqueue_count = kq->kq_count;
2326 kif->kf_un.kf_kqueue.kf_kqueue_state = kq->kq_state;
2327 return (0);
2328 }
2329
2330 static void
2331 kqueue_wakeup(struct kqueue *kq)
2332 {
2333 KQ_OWNED(kq);
2334
2335 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
2336 kq->kq_state &= ~KQ_SLEEP;
2337 wakeup(kq);
2338 }
2339 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
2340 selwakeuppri(&kq->kq_sel, PSOCK);
2341 if (!SEL_WAITING(&kq->kq_sel))
2342 kq->kq_state &= ~KQ_SEL;
2343 }
2344 if (!knlist_empty(&kq->kq_sel.si_note))
2345 kqueue_schedtask(kq);
2346 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
2347 pgsigio(&kq->kq_sigio, SIGIO, 0);
2348 }
2349 }
2350
2351 /*
2352 * Walk down a list of knotes, activating them if their event has triggered.
2353 *
2354 * There is a possibility to optimize in the case of one kq watching another.
2355 * Instead of scheduling a task to wake it up, you could pass enough state
2356 * down the chain to make up the parent kqueue. Make this code functional
2357 * first.
2358 */
2359 void
2360 knote(struct knlist *list, long hint, int lockflags)
2361 {
2362 struct kqueue *kq;
2363 struct knote *kn, *tkn;
2364 int error;
2365
2366 if (list == NULL)
2367 return;
2368
2369 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
2370
2371 if ((lockflags & KNF_LISTLOCKED) == 0)
2372 list->kl_lock(list->kl_lockarg);
2373
2374 /*
2375 * If we unlock the list lock (and enter influx), we can
2376 * eliminate the kqueue scheduling, but this will introduce
2377 * four lock/unlock's for each knote to test. Also, marker
2378 * would be needed to keep iteration position, since filters
2379 * or other threads could remove events.
2380 */
2381 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) {
2382 kq = kn->kn_kq;
2383 KQ_LOCK(kq);
2384 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) {
2385 /*
2386 * Do not process the influx notes, except for
2387 * the influx coming from the kq unlock in the
2388 * kqueue_scan(). In the later case, we do
2389 * not interfere with the scan, since the code
2390 * fragment in kqueue_scan() locks the knlist,
2391 * and cannot proceed until we finished.
2392 */
2393 KQ_UNLOCK(kq);
2394 } else if ((lockflags & KNF_NOKQLOCK) != 0) {
2395 kn_enter_flux(kn);
2396 KQ_UNLOCK(kq);
2397 error = kn->kn_fop->f_event(kn, hint);
2398 KQ_LOCK(kq);
2399 kn_leave_flux(kn);
2400 if (error)
2401 KNOTE_ACTIVATE(kn, 1);
2402 KQ_UNLOCK_FLUX(kq);
2403 } else {
2404 if (kn->kn_fop->f_event(kn, hint))
2405 KNOTE_ACTIVATE(kn, 1);
2406 KQ_UNLOCK(kq);
2407 }
2408 }
2409 if ((lockflags & KNF_LISTLOCKED) == 0)
2410 list->kl_unlock(list->kl_lockarg);
2411 }
2412
2413 /*
2414 * add a knote to a knlist
2415 */
2416 void
2417 knlist_add(struct knlist *knl, struct knote *kn, int islocked)
2418 {
2419
2420 KNL_ASSERT_LOCK(knl, islocked);
2421 KQ_NOTOWNED(kn->kn_kq);
2422 KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn));
2423 KASSERT((kn->kn_status & KN_DETACHED) != 0,
2424 ("knote %p was not detached", kn));
2425 if (!islocked)
2426 knl->kl_lock(knl->kl_lockarg);
2427 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext);
2428 if (!islocked)
2429 knl->kl_unlock(knl->kl_lockarg);
2430 KQ_LOCK(kn->kn_kq);
2431 kn->kn_knlist = knl;
2432 kn->kn_status &= ~KN_DETACHED;
2433 KQ_UNLOCK(kn->kn_kq);
2434 }
2435
2436 static void
2437 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked,
2438 int kqislocked)
2439 {
2440
2441 KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked"));
2442 KNL_ASSERT_LOCK(knl, knlislocked);
2443 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED);
2444 KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn));
2445 KASSERT((kn->kn_status & KN_DETACHED) == 0,
2446 ("knote %p was already detached", kn));
2447 if (!knlislocked)
2448 knl->kl_lock(knl->kl_lockarg);
2449 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
2450 kn->kn_knlist = NULL;
2451 if (!knlislocked)
2452 kn_list_unlock(knl);
2453 if (!kqislocked)
2454 KQ_LOCK(kn->kn_kq);
2455 kn->kn_status |= KN_DETACHED;
2456 if (!kqislocked)
2457 KQ_UNLOCK(kn->kn_kq);
2458 }
2459
2460 /*
2461 * remove knote from the specified knlist
2462 */
2463 void
2464 knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
2465 {
2466
2467 knlist_remove_kq(knl, kn, islocked, 0);
2468 }
2469
2470 int
2471 knlist_empty(struct knlist *knl)
2472 {
2473
2474 KNL_ASSERT_LOCKED(knl);
2475 return (SLIST_EMPTY(&knl->kl_list));
2476 }
2477
2478 static struct mtx knlist_lock;
2479 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects",
2480 MTX_DEF);
2481 static void knlist_mtx_lock(void *arg);
2482 static void knlist_mtx_unlock(void *arg);
2483
2484 static void
2485 knlist_mtx_lock(void *arg)
2486 {
2487
2488 mtx_lock((struct mtx *)arg);
2489 }
2490
2491 static void
2492 knlist_mtx_unlock(void *arg)
2493 {
2494
2495 mtx_unlock((struct mtx *)arg);
2496 }
2497
2498 static void
2499 knlist_mtx_assert_lock(void *arg, int what)
2500 {
2501
2502 if (what == LA_LOCKED)
2503 mtx_assert((struct mtx *)arg, MA_OWNED);
2504 else
2505 mtx_assert((struct mtx *)arg, MA_NOTOWNED);
2506 }
2507
2508 void
2509 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
2510 void (*kl_unlock)(void *),
2511 void (*kl_assert_lock)(void *, int))
2512 {
2513
2514 if (lock == NULL)
2515 knl->kl_lockarg = &knlist_lock;
2516 else
2517 knl->kl_lockarg = lock;
2518
2519 if (kl_lock == NULL)
2520 knl->kl_lock = knlist_mtx_lock;
2521 else
2522 knl->kl_lock = kl_lock;
2523 if (kl_unlock == NULL)
2524 knl->kl_unlock = knlist_mtx_unlock;
2525 else
2526 knl->kl_unlock = kl_unlock;
2527 if (kl_assert_lock == NULL)
2528 knl->kl_assert_lock = knlist_mtx_assert_lock;
2529 else
2530 knl->kl_assert_lock = kl_assert_lock;
2531
2532 knl->kl_autodestroy = 0;
2533 SLIST_INIT(&knl->kl_list);
2534 }
2535
2536 void
2537 knlist_init_mtx(struct knlist *knl, struct mtx *lock)
2538 {
2539
2540 knlist_init(knl, lock, NULL, NULL, NULL);
2541 }
2542
2543 struct knlist *
2544 knlist_alloc(struct mtx *lock)
2545 {
2546 struct knlist *knl;
2547
2548 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK);
2549 knlist_init_mtx(knl, lock);
2550 return (knl);
2551 }
2552
2553 void
2554 knlist_destroy(struct knlist *knl)
2555 {
2556
2557 KASSERT(KNLIST_EMPTY(knl),
2558 ("destroying knlist %p with knotes on it", knl));
2559 }
2560
2561 void
2562 knlist_detach(struct knlist *knl)
2563 {
2564
2565 KNL_ASSERT_LOCKED(knl);
2566 knl->kl_autodestroy = 1;
2567 if (knlist_empty(knl)) {
2568 knlist_destroy(knl);
2569 free(knl, M_KQUEUE);
2570 }
2571 }
2572
2573 /*
2574 * Even if we are locked, we may need to drop the lock to allow any influx
2575 * knotes time to "settle".
2576 */
2577 void
2578 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
2579 {
2580 struct knote *kn, *kn2;
2581 struct kqueue *kq;
2582
2583 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl));
2584 if (islocked)
2585 KNL_ASSERT_LOCKED(knl);
2586 else {
2587 KNL_ASSERT_UNLOCKED(knl);
2588 again: /* need to reacquire lock since we have dropped it */
2589 knl->kl_lock(knl->kl_lockarg);
2590 }
2591
2592 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
2593 kq = kn->kn_kq;
2594 KQ_LOCK(kq);
2595 if (kn_in_flux(kn)) {
2596 KQ_UNLOCK(kq);
2597 continue;
2598 }
2599 knlist_remove_kq(knl, kn, 1, 1);
2600 if (killkn) {
2601 kn_enter_flux(kn);
2602 KQ_UNLOCK(kq);
2603 knote_drop_detached(kn, td);
2604 } else {
2605 /* Make sure cleared knotes disappear soon */
2606 kn->kn_flags |= EV_EOF | EV_ONESHOT;
2607 KQ_UNLOCK(kq);
2608 }
2609 kq = NULL;
2610 }
2611
2612 if (!SLIST_EMPTY(&knl->kl_list)) {
2613 /* there are still in flux knotes remaining */
2614 kn = SLIST_FIRST(&knl->kl_list);
2615 kq = kn->kn_kq;
2616 KQ_LOCK(kq);
2617 KASSERT(kn_in_flux(kn), ("knote removed w/o list lock"));
2618 knl->kl_unlock(knl->kl_lockarg);
2619 kq->kq_state |= KQ_FLUXWAIT;
2620 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
2621 kq = NULL;
2622 goto again;
2623 }
2624
2625 if (islocked)
2626 KNL_ASSERT_LOCKED(knl);
2627 else {
2628 knl->kl_unlock(knl->kl_lockarg);
2629 KNL_ASSERT_UNLOCKED(knl);
2630 }
2631 }
2632
2633 /*
2634 * Remove all knotes referencing a specified fd must be called with FILEDESC
2635 * lock. This prevents a race where a new fd comes along and occupies the
2636 * entry and we attach a knote to the fd.
2637 */
2638 void
2639 knote_fdclose(struct thread *td, int fd)
2640 {
2641 struct filedesc *fdp = td->td_proc->p_fd;
2642 struct kqueue *kq;
2643 struct knote *kn;
2644 int influx;
2645
2646 FILEDESC_XLOCK_ASSERT(fdp);
2647
2648 /*
2649 * We shouldn't have to worry about new kevents appearing on fd
2650 * since filedesc is locked.
2651 */
2652 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
2653 KQ_LOCK(kq);
2654
2655 again:
2656 influx = 0;
2657 while (kq->kq_knlistsize > fd &&
2658 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
2659 if (kn_in_flux(kn)) {
2660 /* someone else might be waiting on our knote */
2661 if (influx)
2662 wakeup(kq);
2663 kq->kq_state |= KQ_FLUXWAIT;
2664 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
2665 goto again;
2666 }
2667 kn_enter_flux(kn);
2668 KQ_UNLOCK(kq);
2669 influx = 1;
2670 knote_drop(kn, td);
2671 KQ_LOCK(kq);
2672 }
2673 KQ_UNLOCK_FLUX(kq);
2674 }
2675 }
2676
2677 static int
2678 knote_attach(struct knote *kn, struct kqueue *kq)
2679 {
2680 struct klist *list;
2681
2682 KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn));
2683 KQ_OWNED(kq);
2684
2685 if ((kq->kq_state & KQ_CLOSING) != 0)
2686 return (EBADF);
2687 if (kn->kn_fop->f_isfd) {
2688 if (kn->kn_id >= kq->kq_knlistsize)
2689 return (ENOMEM);
2690 list = &kq->kq_knlist[kn->kn_id];
2691 } else {
2692 if (kq->kq_knhash == NULL)
2693 return (ENOMEM);
2694 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2695 }
2696 SLIST_INSERT_HEAD(list, kn, kn_link);
2697 return (0);
2698 }
2699
2700 static void
2701 knote_drop(struct knote *kn, struct thread *td)
2702 {
2703
2704 if ((kn->kn_status & KN_DETACHED) == 0)
2705 kn->kn_fop->f_detach(kn);
2706 knote_drop_detached(kn, td);
2707 }
2708
2709 static void
2710 knote_drop_detached(struct knote *kn, struct thread *td)
2711 {
2712 struct kqueue *kq;
2713 struct klist *list;
2714
2715 kq = kn->kn_kq;
2716
2717 KASSERT((kn->kn_status & KN_DETACHED) != 0,
2718 ("knote %p still attached", kn));
2719 KQ_NOTOWNED(kq);
2720
2721 KQ_LOCK(kq);
2722 KASSERT(kn->kn_influx == 1,
2723 ("knote_drop called on %p with influx %d", kn, kn->kn_influx));
2724
2725 if (kn->kn_fop->f_isfd)
2726 list = &kq->kq_knlist[kn->kn_id];
2727 else
2728 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2729
2730 if (!SLIST_EMPTY(list))
2731 SLIST_REMOVE(list, kn, knote, kn_link);
2732 if (kn->kn_status & KN_QUEUED)
2733 knote_dequeue(kn);
2734 KQ_UNLOCK_FLUX(kq);
2735
2736 if (kn->kn_fop->f_isfd) {
2737 fdrop(kn->kn_fp, td);
2738 kn->kn_fp = NULL;
2739 }
2740 kqueue_fo_release(kn->kn_kevent.filter);
2741 kn->kn_fop = NULL;
2742 knote_free(kn);
2743 }
2744
2745 static void
2746 knote_enqueue(struct knote *kn)
2747 {
2748 struct kqueue *kq = kn->kn_kq;
2749
2750 KQ_OWNED(kn->kn_kq);
2751 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
2752
2753 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
2754 kn->kn_status |= KN_QUEUED;
2755 kq->kq_count++;
2756 kqueue_wakeup(kq);
2757 }
2758
2759 static void
2760 knote_dequeue(struct knote *kn)
2761 {
2762 struct kqueue *kq = kn->kn_kq;
2763
2764 KQ_OWNED(kn->kn_kq);
2765 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
2766
2767 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
2768 kn->kn_status &= ~KN_QUEUED;
2769 kq->kq_count--;
2770 }
2771
2772 static void
2773 knote_init(void)
2774 {
2775
2776 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
2777 NULL, NULL, UMA_ALIGN_PTR, 0);
2778 ast_register(TDA_KQUEUE, ASTR_ASTF_REQUIRED, 0, ast_kqueue);
2779 }
2780 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
2781
2782 static struct knote *
2783 knote_alloc(int mflag)
2784 {
2785
2786 return (uma_zalloc(knote_zone, mflag | M_ZERO));
2787 }
2788
2789 static void
2790 knote_free(struct knote *kn)
2791 {
2792
2793 uma_zfree(knote_zone, kn);
2794 }
2795
2796 /*
2797 * Register the kev w/ the kq specified by fd.
2798 */
2799 int
2800 kqfd_register(int fd, struct kevent *kev, struct thread *td, int mflag)
2801 {
2802 struct kqueue *kq;
2803 struct file *fp;
2804 cap_rights_t rights;
2805 int error;
2806
2807 error = fget(td, fd, cap_rights_init_one(&rights, CAP_KQUEUE_CHANGE),
2808 &fp);
2809 if (error != 0)
2810 return (error);
2811 if ((error = kqueue_acquire(fp, &kq)) != 0)
2812 goto noacquire;
2813
2814 error = kqueue_register(kq, kev, td, mflag);
2815 kqueue_release(kq, 0);
2816
2817 noacquire:
2818 fdrop(fp, td);
2819 return (error);
2820 }
Cache object: 202095e31abb9f3fe4ed14336f785fbf
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