1 /*-
2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
3 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org>
4 * Copyright (c) 2009 Apple, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31
32 #include "opt_ktrace.h"
33 #include "opt_kqueue.h"
34 #include "opt_compat_mach.h"
35
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/capsicum.h>
39 #include <sys/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/rwlock.h>
43 #include <sys/proc.h>
44 #include <sys/malloc.h>
45 #include <sys/unistd.h>
46 #include <sys/file.h>
47 #include <sys/filedesc.h>
48 #include <sys/filio.h>
49 #include <sys/fcntl.h>
50 #include <sys/kthread.h>
51 #include <sys/selinfo.h>
52 #include <sys/stdatomic.h>
53 #include <sys/queue.h>
54 #include <sys/event.h>
55 #include <sys/eventvar.h>
56 #include <sys/poll.h>
57 #include <sys/protosw.h>
58 #include <sys/resourcevar.h>
59 #include <sys/sigio.h>
60 #include <sys/signalvar.h>
61 #include <sys/socket.h>
62 #include <sys/socketvar.h>
63 #include <sys/stat.h>
64 #include <sys/sysctl.h>
65 #include <sys/sysproto.h>
66 #include <sys/syscallsubr.h>
67 #include <sys/taskqueue.h>
68 #include <sys/uio.h>
69 #include <sys/user.h>
70 #ifdef KTRACE
71 #include <sys/ktrace.h>
72 #endif
73
74 #include <vm/uma.h>
75
76 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
77
78 /*
79 * This lock is used if multiple kq locks are required. This possibly
80 * should be made into a per proc lock.
81 */
82 static struct mtx kq_global;
83 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF);
84 #define KQ_GLOBAL_LOCK(lck, haslck) do { \
85 if (!haslck) \
86 mtx_lock(lck); \
87 haslck = 1; \
88 } while (0)
89 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \
90 if (haslck) \
91 mtx_unlock(lck); \
92 haslck = 0; \
93 } while (0)
94
95 TASKQUEUE_DEFINE_THREAD(kqueue);
96
97 static int _kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents,
98 struct kevent_copyops *k_ops, const struct timespec *timeout, int v1);
99 static int _kern_kevent_kq(struct thread *td, struct kqueue *kq, int nchanges, int nevents,
100 struct kevent_copyops *k_ops, const struct timespec *timeout, int v1);
101 static int kevent_copyout(void *arg, void *kevp, int count);
102 static int kevent_copyin(void *arg, void *kevp, int count);
103 static int kevent64_copyout(void *arg, void *kevp, int count);
104 static int kevent64_copyin(void *arg,void *kevp, int count);
105 static int kqueue_register(struct kqueue *kq, struct kevent64_s *kev,
106 struct thread *td, int waitok);
107 static int kqueue_acquire(struct file *fp, struct kqueue **kqp);
108 static void kqueue_release(struct kqueue *kq, int locked);
109 static void kqueue_destroy(struct kqueue *kq);
110 static void kqueue_drain(struct kqueue *kq, struct thread *td);
111 static int kqueue_expand(struct kqueue *kq, struct filterops *fops,
112 uintptr_t ident, int waitok);
113 static void kqueue_task(void *arg, int pending);
114 static int kqueue_scan(struct kqueue *kq, int maxevents,
115 struct kevent_copyops *k_ops,
116 const struct timespec *timeout,
117 struct kevent64_s *keva, struct thread *td);
118 static void kqueue_wakeup(struct kqueue *kq);
119 static struct filterops *kqueue_fo_find(int filt);
120 static void kqueue_fo_release(int filt);
121
122 static fo_ioctl_t kqueue_ioctl;
123 static fo_poll_t kqueue_poll;
124 static fo_kqfilter_t kqueue_kqfilter;
125 static fo_stat_t kqueue_stat;
126 static fo_close_t kqueue_close;
127 static fo_fill_kinfo_t kqueue_fill_kinfo;
128
129 static struct fileops kqueueops = {
130 .fo_read = invfo_rdwr,
131 .fo_write = invfo_rdwr,
132 .fo_truncate = invfo_truncate,
133 .fo_ioctl = kqueue_ioctl,
134 .fo_poll = kqueue_poll,
135 .fo_kqfilter = kqueue_kqfilter,
136 .fo_stat = kqueue_stat,
137 .fo_close = kqueue_close,
138 .fo_chmod = invfo_chmod,
139 .fo_chown = invfo_chown,
140 .fo_sendfile = invfo_sendfile,
141 .fo_fill_kinfo = kqueue_fill_kinfo,
142 };
143
144 static int knote_attach(struct knote *kn, struct kqueue *kq);
145 static void knote_drop(struct knote *kn, struct thread *td);
146 static void knote_dequeue(struct knote *kn);
147 static void knote_init(void);
148 static struct knote *knote_alloc(int waitok);
149 static void knote_free(struct knote *kn);
150
151 static void filt_kqdetach(struct knote *kn);
152 static int filt_kqueue(struct knote *kn, long hint);
153 static int filt_procattach(struct knote *kn);
154 static void filt_procdetach(struct knote *kn);
155 static int filt_proc(struct knote *kn, long hint);
156 static int filt_fileattach(struct knote *kn);
157 static void filt_timerexpire(void *knx);
158 static int filt_timerattach(struct knote *kn);
159 static void filt_timerdetach(struct knote *kn);
160 static int filt_timer(struct knote *kn, long hint);
161 static int filt_userattach(struct knote *kn);
162 static void filt_userdetach(struct knote *kn);
163 static int filt_user(struct knote *kn, long hint);
164 static void filt_usertouch(struct knote *kn, struct kevent64_s *kev,
165 u_long type);
166
167
168 static struct filterops file_filtops = {
169 .f_isfd = 1,
170 .f_attach = filt_fileattach,
171 };
172 static struct filterops kqread_filtops = {
173 .f_isfd = 1,
174 .f_detach = filt_kqdetach,
175 .f_event = filt_kqueue,
176 };
177 /* XXX - move to kern_proc.c? */
178 static struct filterops proc_filtops = {
179 .f_isfd = 0,
180 .f_attach = filt_procattach,
181 .f_detach = filt_procdetach,
182 .f_event = filt_proc,
183 };
184 static struct filterops timer_filtops = {
185 .f_isfd = 0,
186 .f_attach = filt_timerattach,
187 .f_detach = filt_timerdetach,
188 .f_event = filt_timer,
189 };
190 static struct filterops user_filtops = {
191 .f_attach = filt_userattach,
192 .f_detach = filt_userdetach,
193 .f_event = filt_user,
194 .f_touch = filt_usertouch,
195 };
196
197 static uma_zone_t knote_zone;
198 static atomic_uint kq_ncallouts = ATOMIC_VAR_INIT(0);
199 static unsigned int kq_calloutmax = 4 * 1024;
200 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
201 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
202
203 /* XXX - ensure not KN_INFLUX?? */
204 #define KNOTE_ACTIVATE(kn, islock) do { \
205 if ((islock)) \
206 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \
207 else \
208 KQ_LOCK((kn)->kn_kq); \
209 (kn)->kn_status |= KN_ACTIVE; \
210 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
211 knote_enqueue((kn)); \
212 if (!(islock)) \
213 KQ_UNLOCK((kn)->kn_kq); \
214 } while(0)
215 #define KQ_LOCK(kq) do { \
216 mtx_lock(&(kq)->kq_lock); \
217 } while (0)
218 #define KQ_FLUX_WAKEUP(kq) do { \
219 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \
220 (kq)->kq_state &= ~KQ_FLUXWAIT; \
221 wakeup((kq)); \
222 } \
223 } while (0)
224 #define KQ_UNLOCK_FLUX(kq) do { \
225 KQ_FLUX_WAKEUP(kq); \
226 mtx_unlock(&(kq)->kq_lock); \
227 } while (0)
228 #define KQ_UNLOCK(kq) do { \
229 mtx_unlock(&(kq)->kq_lock); \
230 } while (0)
231 #define KQ_OWNED(kq) do { \
232 mtx_assert(&(kq)->kq_lock, MA_OWNED); \
233 } while (0)
234 #define KQ_NOTOWNED(kq) do { \
235 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \
236 } while (0)
237 #define KN_LIST_LOCK(kn) do { \
238 if (kn->kn_knlist != NULL) \
239 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg, __FILE__, __LINE__); \
240 } while (0)
241 #define KNL_LOCK(knlist) do { \
242 if (knlist != NULL) \
243 knlist->kl_lock(knlist->kl_lockarg, __FILE__, __LINE__); \
244 } while (0)
245 #define KN_LIST_UNLOCK(kn) do { \
246 if (kn->kn_knlist != NULL) \
247 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \
248 } while (0)
249 #define KNL_ASSERT_LOCK(knl, islocked) do { \
250 if (islocked) \
251 KNL_ASSERT_LOCKED(knl); \
252 else \
253 KNL_ASSERT_UNLOCKED(knl); \
254 } while (0)
255 #ifdef INVARIANTS
256 #define KNL_ASSERT_LOCKED(knl) do { \
257 knl->kl_assert_locked((knl)->kl_lockarg); \
258 } while (0)
259 #define KNL_ASSERT_UNLOCKED(knl) do { \
260 knl->kl_assert_unlocked((knl)->kl_lockarg); \
261 } while (0)
262 #else /* !INVARIANTS */
263 #define KNL_ASSERT_LOCKED(knl) do {} while(0)
264 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
265 #endif /* INVARIANTS */
266
267 #ifndef KN_HASHSIZE
268 #define KN_HASHSIZE 64 /* XXX should be tunable */
269 #endif
270
271 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
272
273 static int
filt_nullattach(struct knote * kn)274 filt_nullattach(struct knote *kn)
275 {
276
277 return (ENXIO);
278 };
279
280 struct filterops null_filtops = {
281 .f_isfd = 0,
282 .f_attach = filt_nullattach,
283 };
284
285 /* XXX - make SYSINIT to add these, and move into respective modules. */
286 extern struct filterops sig_filtops;
287 extern struct filterops fs_filtops;
288
289 /*
290 * Table for for all system-defined filters.
291 */
292 static struct mtx filterops_lock;
293 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops",
294 MTX_DEF);
295 static struct {
296 struct filterops *for_fop;
297 int for_nolock;
298 int for_refcnt;
299 } sysfilt_ops[EVFILT_SYSCOUNT] = {
300 { &file_filtops, 1 }, /* EVFILT_READ */
301 { &file_filtops, 1 }, /* EVFILT_WRITE */
302 { &null_filtops }, /* EVFILT_AIO */
303 { &file_filtops, 1 }, /* EVFILT_VNODE */
304 { &proc_filtops, 1 }, /* EVFILT_PROC */
305 { &sig_filtops, 1 }, /* EVFILT_SIGNAL */
306 { &timer_filtops, 1 }, /* EVFILT_TIMER */
307 { &file_filtops, 1 }, /* EVFILT_PROCDESC */
308 { &fs_filtops, 1 }, /* EVFILT_FS */
309 { &null_filtops }, /* EVFILT_LIO */
310 { &user_filtops, 1 }, /* EVFILT_USER */
311 { &null_filtops }, /* EVFILT_SENDFILE */
312 { &null_filtops , 1}, /* EVFILT_MACHPORT */
313 { &null_filtops }, /* EVFILT_VM */
314 };
315
316 /*
317 * Simple redirection for all cdevsw style objects to call their fo_kqfilter
318 * method.
319 */
320 static int
filt_fileattach(struct knote * kn)321 filt_fileattach(struct knote *kn)
322 {
323
324 return (fo_kqfilter(kn->kn_fp, kn));
325 }
326
327 /*ARGSUSED*/
328 static int
kqueue_kqfilter(struct file * fp,struct knote * kn)329 kqueue_kqfilter(struct file *fp, struct knote *kn)
330 {
331 struct kqueue *kq = kn->kn_fp->f_data;
332
333 if (kn->kn_filter != EVFILT_READ)
334 return (EINVAL);
335
336 kn->kn_status |= KN_KQUEUE;
337 kn->kn_fop = &kqread_filtops;
338 knlist_add(&kq->kq_sel.si_note, kn, 0);
339
340 return (0);
341 }
342
343 static void
filt_kqdetach(struct knote * kn)344 filt_kqdetach(struct knote *kn)
345 {
346 struct kqueue *kq = kn->kn_fp->f_data;
347
348 knlist_remove(&kq->kq_sel.si_note, kn, 0);
349 }
350
351 /*ARGSUSED*/
352 static int
filt_kqueue(struct knote * kn,long hint)353 filt_kqueue(struct knote *kn, long hint)
354 {
355 struct kqueue *kq = kn->kn_fp->f_data;
356
357 kn->kn_data = kq->kq_count;
358 return (kn->kn_data > 0);
359 }
360
361 /* XXX - move to kern_proc.c? */
362 static int
filt_procattach(struct knote * kn)363 filt_procattach(struct knote *kn)
364 {
365 struct proc *p;
366 int immediate;
367 int error;
368
369 immediate = 0;
370 p = pfind(kn->kn_id);
371 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
372 p = zpfind(kn->kn_id);
373 immediate = 1;
374 } else if (p != NULL && (p->p_flag & P_WEXIT)) {
375 immediate = 1;
376 }
377
378 if (p == NULL)
379 return (ESRCH);
380 if ((error = p_cansee(curthread, p))) {
381 PROC_UNLOCK(p);
382 return (error);
383 }
384
385 kn->kn_ptr.p_proc = p;
386 kn->kn_flags |= EV_CLEAR; /* automatically set */
387
388 /*
389 * internal flag indicating registration done by kernel
390 */
391 if (kn->kn_flags & EV_FLAG1) {
392 kn->kn_data = kn->kn_sdata; /* ppid */
393 kn->kn_fflags = NOTE_CHILD;
394 kn->kn_flags &= ~EV_FLAG1;
395 }
396
397 if (immediate == 0)
398 knlist_add(&p->p_klist, kn, 1);
399
400 /*
401 * Immediately activate any exit notes if the target process is a
402 * zombie. This is necessary to handle the case where the target
403 * process, e.g. a child, dies before the kevent is registered.
404 */
405 if (immediate && filt_proc(kn, NOTE_EXIT))
406 KNOTE_ACTIVATE(kn, 0);
407
408 PROC_UNLOCK(p);
409
410 return (0);
411 }
412
413 /*
414 * The knote may be attached to a different process, which may exit,
415 * leaving nothing for the knote to be attached to. So when the process
416 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
417 * it will be deleted when read out. However, as part of the knote deletion,
418 * this routine is called, so a check is needed to avoid actually performing
419 * a detach, because the original process does not exist any more.
420 */
421 /* XXX - move to kern_proc.c? */
422 static void
filt_procdetach(struct knote * kn)423 filt_procdetach(struct knote *kn)
424 {
425 struct proc *p;
426
427 p = kn->kn_ptr.p_proc;
428 knlist_remove(&p->p_klist, kn, 0);
429 kn->kn_ptr.p_proc = NULL;
430 }
431
432 /* XXX - move to kern_proc.c? */
433 static int
filt_proc(struct knote * kn,long hint)434 filt_proc(struct knote *kn, long hint)
435 {
436 struct proc *p;
437 u_int event;
438
439 p = kn->kn_ptr.p_proc;
440 /* Mask off extra data. */
441 event = (u_int)hint & NOTE_PCTRLMASK;
442
443 /* If the user is interested in this event, record it. */
444 if (kn->kn_sfflags & event)
445 kn->kn_fflags |= event;
446
447 /* Process is gone, so flag the event as finished. */
448 if (event == NOTE_EXIT) {
449 if (!(kn->kn_status & KN_DETACHED))
450 knlist_remove_inevent(&p->p_klist, kn);
451 kn->kn_flags |= EV_EOF | EV_ONESHOT;
452 kn->kn_ptr.p_proc = NULL;
453 if (kn->kn_fflags & NOTE_EXIT) {
454 kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig);
455 /* Darwin compatibility */
456 if (kn->kn_sfflags & NOTE_EXITSTATUS)
457 kn->kn_fflags |= NOTE_EXITSTATUS;
458 }
459 if (kn->kn_fflags == 0)
460 kn->kn_flags |= EV_DROP;
461 return (1);
462 }
463
464 return (kn->kn_fflags != 0);
465 }
466
467 /*
468 * Called when the process forked. It mostly does the same as the
469 * knote(), activating all knotes registered to be activated when the
470 * process forked. Additionally, for each knote attached to the
471 * parent, check whether user wants to track the new process. If so
472 * attach a new knote to it, and immediately report an event with the
473 * child's pid.
474 */
475 void
knote_fork(struct knlist * list,int pid)476 knote_fork(struct knlist *list, int pid)
477 {
478 struct kqueue *kq;
479 struct knote *kn;
480 struct kevent64_s kev;
481 int error;
482
483 if (list == NULL)
484 return;
485 KNL_LOCK(list);
486
487 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
488 /*
489 * XXX - Why do we skip the kn if it is _INFLUX? Does this
490 * mean we will not properly wake up some notes?
491 */
492 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX)
493 continue;
494 kq = kn->kn_kq;
495 KQ_LOCK(kq);
496 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) {
497 KQ_UNLOCK(kq);
498 continue;
499 }
500
501 /*
502 * The same as knote(), activate the event.
503 */
504 if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
505 kn->kn_status |= KN_HASKQLOCK;
506 if (kn->kn_fop->f_event(kn, NOTE_FORK))
507 KNOTE_ACTIVATE(kn, 1);
508 kn->kn_status &= ~KN_HASKQLOCK;
509 KQ_UNLOCK(kq);
510 continue;
511 }
512
513 /*
514 * The NOTE_TRACK case. In addition to the activation
515 * of the event, we need to register new event to
516 * track the child. Drop the locks in preparation for
517 * the call to kqueue_register().
518 */
519 kn->kn_status |= KN_INFLUX;
520 KQ_UNLOCK(kq);
521 list->kl_unlock(list->kl_lockarg);
522
523 /*
524 * Activate existing knote and register a knote with
525 * new process.
526 */
527 kev.ident = pid;
528 kev.filter = kn->kn_filter;
529 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
530 kev.fflags = kn->kn_sfflags;
531 kev.data = kn->kn_id; /* parent */
532 kev.udata = kn->kn_kevent.udata;/* preserve udata */
533 error = kqueue_register(kq, &kev, NULL, 0);
534 if (error)
535 kn->kn_fflags |= NOTE_TRACKERR;
536 if (kn->kn_fop->f_event(kn, NOTE_FORK))
537 KNOTE_ACTIVATE(kn, 0);
538 KQ_LOCK(kq);
539 kn->kn_status &= ~KN_INFLUX;
540 KQ_UNLOCK_FLUX(kq);
541 KNL_LOCK(list);
542 }
543 list->kl_unlock(list->kl_lockarg);
544 }
545
546 /*
547 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the
548 * interval timer support code.
549 */
550
551 #define NOTE_TIMER_PRECMASK (NOTE_SECONDS|NOTE_MSECONDS|NOTE_USECONDS| \
552 NOTE_NSECONDS)
553
554 static __inline sbintime_t
timer2sbintime(intptr_t data,int flags)555 timer2sbintime(intptr_t data, int flags)
556 {
557 sbintime_t modifier;
558
559 switch (flags & NOTE_TIMER_PRECMASK) {
560 case NOTE_SECONDS:
561 modifier = SBT_1S;
562 break;
563 case NOTE_MSECONDS: /* FALLTHROUGH */
564 case 0:
565 modifier = SBT_1MS;
566 break;
567 case NOTE_USECONDS:
568 modifier = SBT_1US;
569 break;
570 case NOTE_NSECONDS:
571 modifier = SBT_1NS;
572 break;
573 default:
574 return (-1);
575 }
576
577 #ifdef __LP64__
578 if (data > SBT_MAX / modifier)
579 return (SBT_MAX);
580 #endif
581 return (modifier * data);
582 }
583
584 static void
filt_timerexpire(void * knx)585 filt_timerexpire(void *knx)
586 {
587 struct callout *calloutp;
588 struct knote *kn;
589
590 kn = knx;
591 kn->kn_data++;
592 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
593
594 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) {
595 calloutp = (struct callout *)kn->kn_hook;
596 *kn->kn_ptr.p_nexttime += timer2sbintime(kn->kn_sdata,
597 kn->kn_sfflags);
598 callout_reset_sbt_on(calloutp, *kn->kn_ptr.p_nexttime, 0,
599 filt_timerexpire, kn, PCPU_GET(cpuid), C_ABSOLUTE);
600 }
601 }
602
603 /*
604 * data contains amount of time to sleep
605 */
606 static int
filt_timerattach(struct knote * kn)607 filt_timerattach(struct knote *kn)
608 {
609 struct callout *calloutp;
610 sbintime_t to;
611 unsigned int ncallouts;
612
613 if ((intptr_t)kn->kn_sdata < 0)
614 return (EINVAL);
615 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0)
616 kn->kn_sdata = 1;
617 /* Only precision unit are supported in flags so far */
618 if (kn->kn_sfflags & ~NOTE_TIMER_PRECMASK)
619 return (EINVAL);
620
621 to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags);
622 if (to < 0)
623 return (EINVAL);
624
625 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed);
626 do {
627 if (ncallouts >= kq_calloutmax)
628 return (ENOMEM);
629 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts,
630 &ncallouts, ncallouts + 1, memory_order_relaxed,
631 memory_order_relaxed));
632
633 kn->kn_flags |= EV_CLEAR; /* automatically set */
634 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */
635 kn->kn_ptr.p_nexttime = malloc(sizeof(sbintime_t), M_KQUEUE, M_WAITOK);
636 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK);
637 callout_init(calloutp, 1);
638 kn->kn_hook = calloutp;
639 *kn->kn_ptr.p_nexttime = to + sbinuptime();
640 callout_reset_sbt_on(calloutp, *kn->kn_ptr.p_nexttime, 0,
641 filt_timerexpire, kn, PCPU_GET(cpuid), C_ABSOLUTE);
642
643 return (0);
644 }
645
646 static void
filt_timerdetach(struct knote * kn)647 filt_timerdetach(struct knote *kn)
648 {
649 struct callout *calloutp;
650 unsigned int old;
651
652 calloutp = (struct callout *)kn->kn_hook;
653 callout_drain(calloutp);
654 free(calloutp, M_KQUEUE);
655 free(kn->kn_ptr.p_nexttime, M_KQUEUE);
656 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed);
657 KASSERT(old > 0, ("Number of callouts cannot become negative"));
658 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */
659 }
660
661 static int
filt_timer(struct knote * kn,long hint)662 filt_timer(struct knote *kn, long hint)
663 {
664
665 return (kn->kn_data != 0);
666 }
667
668 static int
filt_userattach(struct knote * kn)669 filt_userattach(struct knote *kn)
670 {
671
672 /*
673 * EVFILT_USER knotes are not attached to anything in the kernel.
674 */
675 kn->kn_hook = NULL;
676 if (kn->kn_fflags & NOTE_TRIGGER)
677 kn->kn_hookid = 1;
678 else
679 kn->kn_hookid = 0;
680 return (0);
681 }
682
683 static void
filt_userdetach(__unused struct knote * kn)684 filt_userdetach(__unused struct knote *kn)
685 {
686
687 /*
688 * EVFILT_USER knotes are not attached to anything in the kernel.
689 */
690 }
691
692 static int
filt_user(struct knote * kn,__unused long hint)693 filt_user(struct knote *kn, __unused long hint)
694 {
695
696 return (kn->kn_hookid);
697 }
698
699 static void
filt_usertouch(struct knote * kn,struct kevent64_s * kev,u_long type)700 filt_usertouch(struct knote *kn, struct kevent64_s *kev, u_long type)
701 {
702 u_int ffctrl;
703
704 switch (type) {
705 case EVENT_REGISTER:
706 if (kev->fflags & NOTE_TRIGGER)
707 kn->kn_hookid = 1;
708
709 ffctrl = kev->fflags & NOTE_FFCTRLMASK;
710 kev->fflags &= NOTE_FFLAGSMASK;
711 switch (ffctrl) {
712 case NOTE_FFNOP:
713 break;
714
715 case NOTE_FFAND:
716 kn->kn_sfflags &= kev->fflags;
717 break;
718
719 case NOTE_FFOR:
720 kn->kn_sfflags |= kev->fflags;
721 break;
722
723 case NOTE_FFCOPY:
724 kn->kn_sfflags = kev->fflags;
725 break;
726
727 default:
728 /* XXX Return error? */
729 break;
730 }
731 kn->kn_sdata = kev->data;
732 if (kev->flags & EV_CLEAR) {
733 kn->kn_hookid = 0;
734 kn->kn_data = 0;
735 kn->kn_fflags = 0;
736 }
737 break;
738
739 case EVENT_PROCESS:
740 *kev = kn->kn_kevent;
741 kev->fflags = kn->kn_sfflags;
742 kev->data = kn->kn_sdata;
743 if (kn->kn_flags & EV_CLEAR) {
744 kn->kn_hookid = 0;
745 kn->kn_data = 0;
746 kn->kn_fflags = 0;
747 }
748 break;
749
750 default:
751 panic("filt_usertouch() - invalid type (%ld)", type);
752 break;
753 }
754 }
755
756 int
sys_kqueue(struct thread * td,struct kqueue_args * uap)757 sys_kqueue(struct thread *td, struct kqueue_args *uap)
758 {
759
760 return (kern_kqueue(td, 0, NULL));
761 }
762
763 static void
kqueue_init(struct kqueue * kq)764 kqueue_init(struct kqueue *kq)
765 {
766
767 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK);
768 TAILQ_INIT(&kq->kq_head);
769 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
770 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
771 }
772
773 int
kern_kqueue(struct thread * td,int flags,struct filecaps * fcaps)774 kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps)
775 {
776 struct filedesc *fdp;
777 struct kqueue *kq;
778 struct file *fp;
779 struct ucred *cred;
780 int fd, error;
781
782 fdp = td->td_proc->p_fd;
783 cred = td->td_ucred;
784 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES)))
785 return (ENOMEM);
786
787 error = falloc_caps(td, &fp, &fd, flags, fcaps);
788 if (error != 0) {
789 chgkqcnt(cred->cr_ruidinfo, -1, 0);
790 return (error);
791 }
792
793 /* An extra reference on `fp' has been held for us by falloc(). */
794 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
795 kqueue_init(kq);
796 kq->kq_fdp = fdp;
797 kq->kq_cred = crhold(cred);
798
799 FILEDESC_XLOCK(fdp);
800 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
801 FILEDESC_XUNLOCK(fdp);
802
803 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
804 fdrop(fp, td);
805
806 td->td_retval[0] = fd;
807 return (0);
808 }
809
810 #ifndef _SYS_SYSPROTO_H_
811 struct kevent64_args {
812 int fd;
813 struct kevent64_s *changelist;
814 int nchanges;
815 struct kevent64_s *eventlist;
816 int nevents;
817 const struct timespec *timeout;
818 };
819 #endif
820 int
sys_kevent64(struct thread * td,struct kevent64_args * uap)821 sys_kevent64(struct thread *td, struct kevent64_args *uap)
822 {
823 struct timespec ts, *tsp;
824 struct kevent_copyops k_ops = { uap,
825 kevent64_copyout,
826 kevent64_copyin};
827 int error;
828
829 if (uap->timeout != NULL) {
830 error = copyin(uap->timeout, &ts, sizeof(ts));
831 if (error)
832 return (error);
833 tsp = &ts;
834 } else
835 tsp = NULL;
836
837 error = kern_kevent64(td, uap->fd, uap->nchanges, uap->nevents,
838 &k_ops, tsp);
839
840 return (error);
841 }
842
843 #ifndef _SYS_SYSPROTO_H_
844 struct kevent_args {
845 int fd;
846 const struct kevent *changelist;
847 int nchanges;
848 struct kevent *eventlist;
849 int nevents;
850 const struct timespec *timeout;
851 };
852 #endif
853 int
sys_kevent(struct thread * td,struct kevent_args * uap)854 sys_kevent(struct thread *td, struct kevent_args *uap)
855 {
856 struct timespec ts, *tsp;
857 struct kevent_copyops k_ops = { uap,
858 kevent_copyout,
859 kevent_copyin};
860 int error;
861 #ifdef KTRACE
862 struct uio ktruio;
863 struct iovec ktriov;
864 struct uio *ktruioin = NULL;
865 struct uio *ktruioout = NULL;
866 #endif
867
868 if (uap->timeout != NULL) {
869 error = copyin(uap->timeout, &ts, sizeof(ts));
870 if (error)
871 return (error);
872 tsp = &ts;
873 } else
874 tsp = NULL;
875
876 #ifdef KTRACE
877 if (KTRPOINT(td, KTR_GENIO)) {
878 ktriov.iov_base = uap->changelist;
879 ktriov.iov_len = uap->nchanges * sizeof(struct kevent);
880 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1,
881 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ,
882 .uio_td = td };
883 ktruioin = cloneuio(&ktruio);
884 ktriov.iov_base = uap->eventlist;
885 ktriov.iov_len = uap->nevents * sizeof(struct kevent);
886 ktruioout = cloneuio(&ktruio);
887 }
888 #endif
889
890 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
891 &k_ops, tsp);
892
893 #ifdef KTRACE
894 if (ktruioin != NULL) {
895 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent);
896 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0);
897 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent);
898 ktrgenio(uap->fd, UIO_READ, ktruioout, error);
899 }
900 #endif
901
902 return (error);
903 }
904
905 /*
906 * Copy 'count' items into the destination list pointed to by uap->eventlist.
907 */
908 static int
kevent64_copyout(void * arg,void * kevp,int count)909 kevent64_copyout(void *arg, void *kevp, int count)
910 {
911 struct kevent64_args *uap;
912 int error;
913
914 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
915 uap = (struct kevent64_args *)arg;
916
917 error = copyout(kevp, uap->eventlist, count * sizeof(struct kevent64_s));
918 if (error == 0)
919 uap->eventlist += count;
920 return (error);
921 }
922
923 static int
kevent_copyout(void * arg,void * kevp,int count)924 kevent_copyout(void *arg, void *kevp, int count)
925 {
926 struct kevent64_s *kev;
927 struct kevent_args *uap;
928 int error, i;
929
930 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
931 uap = (struct kevent_args *)arg;
932 kev = (struct kevent64_s *)kevp;
933
934 for (i = 0; i < count; i++) {
935 error = copyout((const void *)&kev[i], uap->eventlist, sizeof(struct kevent));
936 if (error == 0)
937 uap->eventlist++;
938 }
939
940 return (error);
941 }
942
943 /*
944 * Copy 'count' items from the list pointed to by uap->changelist.
945 */
946 static int
kevent64_copyin(void * arg,void * kevp,int count)947 kevent64_copyin(void *arg, void *kevp, int count)
948 {
949 struct kevent64_args *uap;
950 int error;
951
952 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
953 uap = (struct kevent64_args *)arg;
954
955 error = copyin(uap->changelist, kevp, count * sizeof(struct kevent64_s));
956 if (error == 0)
957 uap->changelist += count;
958 return (error);
959 }
960
961 static int
kevent_copyin(void * arg,void * kevp,int count)962 kevent_copyin(void *arg, void *kevp, int count)
963 {
964 struct kevent_args *uap;
965 int error;
966
967 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
968 uap = (struct kevent_args *)arg;
969
970 error = copyin(uap->changelist, kevp, count * sizeof(struct kevent));
971 if (error == 0)
972 uap->changelist += count;
973 return (error);
974 }
975
976 int
kern_kevent(struct thread * td,int fd,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout)977 kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
978 struct kevent_copyops *k_ops, const struct timespec *timeout)
979 {
980 cap_rights_t rights;
981 struct file *fp;
982 int error;
983
984 cap_rights_init(&rights);
985 if (nchanges > 0)
986 cap_rights_set(&rights, CAP_KQUEUE_CHANGE);
987 if (nevents > 0)
988 cap_rights_set(&rights, CAP_KQUEUE_EVENT);
989 error = fget(td, fd, &rights, &fp);
990 if (error != 0)
991 return (error);
992
993 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout);
994 fdrop(fp, td);
995
996 return (error);
997 }
998
999 int
kern_kevent64(struct thread * td,int fd,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout)1000 kern_kevent64(struct thread *td, int fd, int nchanges, int nevents,
1001 struct kevent_copyops *k_ops, const struct timespec *timeout)
1002 {
1003 cap_rights_t rights;
1004 struct file *fp;
1005 int error;
1006
1007 cap_rights_init(&rights);
1008 if (nchanges > 0)
1009 cap_rights_set(&rights, CAP_KQUEUE_CHANGE);
1010 if (nevents > 0)
1011 cap_rights_set(&rights, CAP_KQUEUE_EVENT);
1012 error = fget(td, fd, &rights, &fp);
1013 if (error != 0)
1014 return (error);
1015
1016 error = kern_kevent_fp64(td, fp, nchanges, nevents, k_ops, timeout);
1017 fdrop(fp, td);
1018
1019 return (error);
1020 }
1021
1022 int
kern_kevent_fp(struct thread * td,struct file * fp,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout)1023 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents,
1024 struct kevent_copyops *k_ops, const struct timespec *timeout)
1025 {
1026
1027 return (_kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout, 0));
1028 }
1029
1030 int
kern_kevent_fp64(struct thread * td,struct file * fp,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout)1031 kern_kevent_fp64(struct thread *td, struct file *fp, int nchanges, int nevents,
1032 struct kevent_copyops *k_ops, const struct timespec *timeout)
1033 {
1034
1035 return (_kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout, 1));
1036 }
1037
1038 static int
_kern_kevent_fp(struct thread * td,struct file * fp,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout,int version)1039 _kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents,
1040 struct kevent_copyops *k_ops, const struct timespec *timeout, int version)
1041 {
1042 struct kqueue *kq;
1043 int error;
1044
1045 if ((error = kqueue_acquire(fp, &kq)))
1046 return (error);
1047 error = _kern_kevent_kq(td, kq, nchanges, nevents, k_ops, timeout, version);
1048 kqueue_release(kq, 0);
1049 return (error);
1050 }
1051
1052 static int
_kern_kevent_kq(struct thread * td,struct kqueue * kq,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout,int v1)1053 _kern_kevent_kq(struct thread *td, struct kqueue *kq, int nchanges, int nevents,
1054 struct kevent_copyops *k_ops, const struct timespec *timeout, int v1)
1055 { struct kevent keva[KQ_NEVENTS];
1056 struct kevent64_s keva64[KQ_NEVENTS];
1057 struct kevent *changes;
1058 struct kevent64_s kevtmp, *kevp;
1059 int i, n, nerrors, error;
1060
1061 nerrors = 0;
1062 if (v1) {
1063 struct kevent64_s *changes;
1064 while (nchanges > 0) {
1065 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
1066 error = k_ops->k_copyin(k_ops->arg, keva64, n);
1067 if (error)
1068 return (error);
1069 changes = keva64;
1070 for (i = 0; i < n; i++) {
1071 kevp = &changes[i];
1072 if (!kevp->filter)
1073 continue;
1074 kevp->flags &= ~EV_SYSFLAGS;
1075 error = kqueue_register(kq, kevp, td, 1);
1076 if (error || (kevp->flags & EV_RECEIPT)) {
1077 if (nevents != 0) {
1078 kevp->flags = EV_ERROR;
1079 kevp->data = error;
1080 (void) k_ops->k_copyout(k_ops->arg,
1081 kevp, 1);
1082 nevents--;
1083 nerrors++;
1084 } else {
1085 return (error);
1086 }
1087 }
1088 }
1089 nchanges -= n;
1090 }
1091 goto check_errors;
1092 }
1093 kevtmp.ext[0] = 0;
1094 kevtmp.ext[1] = 0;
1095 while (nchanges > 0) {
1096 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
1097 error = k_ops->k_copyin(k_ops->arg, keva, n);
1098 if (error)
1099 return (error);
1100 changes = keva;
1101 for (i = 0; i < n; i++) {
1102 kevp = (struct kevent64_s *)&changes[i];
1103 if (!kevp->filter)
1104 continue;
1105 EV_SET64(&kevtmp, kevp->ident, kevp->filter, kevp->flags, kevp->fflags, kevp->data, kevp->udata, 0, 0);
1106 kevp = &kevtmp;
1107 kevp->flags &= ~EV_SYSFLAGS;
1108 error = kqueue_register(kq, kevp, td, 1);
1109 if (error || (kevp->flags & EV_RECEIPT)) {
1110 if (nevents == 0)
1111 return (error);
1112 kevp->flags = EV_ERROR;
1113 kevp->data = error;
1114 (void)k_ops->k_copyout(k_ops->arg, kevp, 1);
1115 nevents--;
1116 nerrors++;
1117 }
1118 }
1119 nchanges -= n;
1120 }
1121 check_errors:
1122 if (nerrors) {
1123 td->td_retval[0] = nerrors;
1124 return (0);
1125 }
1126 if (v1 == 0)
1127 for (i = 0; i < KQ_NEVENTS; i++) {
1128 struct kevent *k = &keva[i];
1129 EV_SET64(&keva64[i], k->ident, k->filter, k->flags, k->fflags, k->data, (uint64_t)k->udata, 0, 0);
1130 }
1131 return (kqueue_scan(kq, nevents, k_ops, timeout, keva64, td));
1132 }
1133
1134 /*
1135 * Performs a kevent() call on a temporarily created kqueue. This can be
1136 * used to perform one-shot polling, similar to poll() and select().
1137 */
1138 int
kern_kevent_anonymous(struct thread * td,int nevents,struct kevent_copyops * k_ops)1139 kern_kevent_anonymous(struct thread *td, int nevents,
1140 struct kevent_copyops *k_ops)
1141 {
1142 struct kqueue kq = {};
1143 int error;
1144
1145 kqueue_init(&kq);
1146 kq.kq_refcnt = 1;
1147 error = _kern_kevent_kq(td, &kq, nevents, nevents, k_ops, NULL, 0);
1148 kqueue_drain(&kq, td);
1149 kqueue_destroy(&kq);
1150 return (error);
1151 }
1152
1153 int
kqueue_add_filteropts(int filt,struct filterops * filtops)1154 kqueue_add_filteropts(int filt, struct filterops *filtops)
1155 {
1156 int error;
1157
1158 error = 0;
1159 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
1160 printf(
1161 "trying to add a filterop that is out of range: %d is beyond %d\n",
1162 ~filt, EVFILT_SYSCOUNT);
1163 return EINVAL;
1164 }
1165 mtx_lock(&filterops_lock);
1166 if (sysfilt_ops[~filt].for_fop != &null_filtops &&
1167 sysfilt_ops[~filt].for_fop != NULL)
1168 error = EEXIST;
1169 else {
1170 sysfilt_ops[~filt].for_fop = filtops;
1171 sysfilt_ops[~filt].for_refcnt = 0;
1172 }
1173 mtx_unlock(&filterops_lock);
1174
1175 return (error);
1176 }
1177
1178 int
kqueue_del_filteropts(int filt)1179 kqueue_del_filteropts(int filt)
1180 {
1181 int error;
1182
1183 error = 0;
1184 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1185 return EINVAL;
1186
1187 mtx_lock(&filterops_lock);
1188 if (sysfilt_ops[~filt].for_fop == &null_filtops ||
1189 sysfilt_ops[~filt].for_fop == NULL)
1190 error = EINVAL;
1191 else if (sysfilt_ops[~filt].for_refcnt != 0)
1192 error = EBUSY;
1193 else {
1194 sysfilt_ops[~filt].for_fop = &null_filtops;
1195 sysfilt_ops[~filt].for_refcnt = 0;
1196 }
1197 mtx_unlock(&filterops_lock);
1198
1199 return error;
1200 }
1201
1202 static struct filterops *
kqueue_fo_find(int filt)1203 kqueue_fo_find(int filt)
1204 {
1205
1206 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1207 return NULL;
1208
1209 if (sysfilt_ops[~filt].for_nolock)
1210 return sysfilt_ops[~filt].for_fop;
1211
1212 mtx_lock(&filterops_lock);
1213 sysfilt_ops[~filt].for_refcnt++;
1214 if (sysfilt_ops[~filt].for_fop == NULL)
1215 sysfilt_ops[~filt].for_fop = &null_filtops;
1216 mtx_unlock(&filterops_lock);
1217
1218 return sysfilt_ops[~filt].for_fop;
1219 }
1220
1221 static void
kqueue_fo_release(int filt)1222 kqueue_fo_release(int filt)
1223 {
1224
1225 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1226 return;
1227
1228 if (sysfilt_ops[~filt].for_nolock)
1229 return;
1230
1231 mtx_lock(&filterops_lock);
1232 KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
1233 ("filter object refcount not valid on release"));
1234 sysfilt_ops[~filt].for_refcnt--;
1235 mtx_unlock(&filterops_lock);
1236 }
1237
1238 /*
1239 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will
1240 * influence if memory allocation should wait. Make sure it is 0 if you
1241 * hold any mutexes.
1242 */
1243 static int
kqueue_register(struct kqueue * kq,struct kevent64_s * kev,struct thread * td,int waitok)1244 kqueue_register(struct kqueue *kq, struct kevent64_s *kev, struct thread *td, int waitok)
1245 {
1246 struct filterops *fops;
1247 struct file *fp;
1248 struct knote *kn, *tkn;
1249 cap_rights_t rights;
1250 int error, filt, event;
1251 int haskqglobal, filedesc_unlock;
1252
1253 fp = NULL;
1254 kn = NULL;
1255 error = 0;
1256 haskqglobal = 0;
1257 filedesc_unlock = 0;
1258
1259 filt = kev->filter;
1260 fops = kqueue_fo_find(filt);
1261 if (fops == NULL)
1262 return EINVAL;
1263
1264 if (kev->flags & EV_ADD) {
1265 /*
1266 * Prevent waiting with locks. Non-sleepable
1267 * allocation failures are handled in the loop, only
1268 * if the spare knote appears to be actually required.
1269 */
1270 tkn = knote_alloc(waitok);
1271 } else {
1272 tkn = NULL;
1273 }
1274
1275 findkn:
1276 if (fops->f_isfd) {
1277 KASSERT(td != NULL, ("td is NULL"));
1278 error = fget(td, kev->ident,
1279 cap_rights_init(&rights, CAP_EVENT), &fp);
1280 if (error)
1281 goto done;
1282
1283 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
1284 kev->ident, 0) != 0) {
1285 /* try again */
1286 fdrop(fp, td);
1287 fp = NULL;
1288 error = kqueue_expand(kq, fops, kev->ident, waitok);
1289 if (error)
1290 goto done;
1291 goto findkn;
1292 }
1293
1294 if (fp->f_type == DTYPE_KQUEUE) {
1295 /*
1296 * if we add some inteligence about what we are doing,
1297 * we should be able to support events on ourselves.
1298 * We need to know when we are doing this to prevent
1299 * getting both the knlist lock and the kq lock since
1300 * they are the same thing.
1301 */
1302 if (fp->f_data == kq) {
1303 error = EINVAL;
1304 goto done;
1305 }
1306
1307 /*
1308 * Pre-lock the filedesc before the global
1309 * lock mutex, see the comment in
1310 * kqueue_close().
1311 */
1312 FILEDESC_XLOCK(td->td_proc->p_fd);
1313 filedesc_unlock = 1;
1314 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1315 }
1316
1317 KQ_LOCK(kq);
1318 if (kev->ident < kq->kq_knlistsize) {
1319 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
1320 if (kev->filter == kn->kn_filter)
1321 break;
1322 }
1323 } else {
1324 if ((kev->flags & EV_ADD) == EV_ADD)
1325 kqueue_expand(kq, fops, kev->ident, waitok);
1326
1327 KQ_LOCK(kq);
1328 if (kq->kq_knhashmask != 0) {
1329 struct klist *list;
1330
1331 list = &kq->kq_knhash[
1332 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
1333 SLIST_FOREACH(kn, list, kn_link)
1334 if (kev->ident == kn->kn_id &&
1335 kev->filter == kn->kn_filter)
1336 break;
1337 }
1338 }
1339
1340 /* knote is in the process of changing, wait for it to stablize. */
1341 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1342 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1343 if (filedesc_unlock) {
1344 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1345 filedesc_unlock = 0;
1346 }
1347 kq->kq_state |= KQ_FLUXWAIT;
1348 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
1349 if (fp != NULL) {
1350 fdrop(fp, td);
1351 fp = NULL;
1352 }
1353 goto findkn;
1354 }
1355
1356 /*
1357 * kn now contains the matching knote, or NULL if no match
1358 */
1359 if (kn == NULL) {
1360 if (kev->flags & EV_ADD) {
1361 kn = tkn;
1362 tkn = NULL;
1363 if (kn == NULL) {
1364 KQ_UNLOCK(kq);
1365 error = ENOMEM;
1366 goto done;
1367 }
1368 kn->kn_fp = fp;
1369 kn->kn_kq = kq;
1370 kn->kn_fop = fops;
1371 /*
1372 * apply reference counts to knote structure, and
1373 * do not release it at the end of this routine.
1374 */
1375 fops = NULL;
1376 fp = NULL;
1377
1378 kn->kn_sfflags = kev->fflags;
1379 kn->kn_sdata = kev->data;
1380 kev->fflags = 0;
1381 kev->data = 0;
1382 kn->kn_kevent = *kev;
1383 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
1384 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT);
1385 kn->kn_status = KN_INFLUX|KN_DETACHED;
1386
1387 error = knote_attach(kn, kq);
1388 KQ_UNLOCK(kq);
1389 if (error != 0) {
1390 tkn = kn;
1391 goto done;
1392 }
1393
1394 if ((error = kn->kn_fop->f_attach(kn)) != 0) {
1395 knote_drop(kn, td);
1396 goto done;
1397 }
1398 KN_LIST_LOCK(kn);
1399 goto done_ev_add;
1400 } else {
1401 /* No matching knote and the EV_ADD flag is not set. */
1402 KQ_UNLOCK(kq);
1403 error = ENOENT;
1404 goto done;
1405 }
1406 }
1407
1408 if (kev->flags & EV_DELETE) {
1409 kn->kn_status |= KN_INFLUX;
1410 KQ_UNLOCK(kq);
1411 if (!(kn->kn_status & KN_DETACHED))
1412 kn->kn_fop->f_detach(kn);
1413 knote_drop(kn, td);
1414 goto done;
1415 }
1416
1417 if (kev->flags & EV_FORCEONESHOT) {
1418 kn->kn_flags |= EV_ONESHOT;
1419 KNOTE_ACTIVATE(kn, 1);
1420 }
1421
1422 /*
1423 * The user may change some filter values after the initial EV_ADD,
1424 * but doing so will not reset any filter which has already been
1425 * triggered.
1426 */
1427 kn->kn_status |= KN_INFLUX | KN_SCAN;
1428 KQ_UNLOCK(kq);
1429 KN_LIST_LOCK(kn);
1430 kn->kn_kevent.udata = kev->udata;
1431 if (!fops->f_isfd && fops->f_touch != NULL) {
1432 fops->f_touch(kn, kev, EVENT_REGISTER);
1433 } else {
1434 kn->kn_sfflags = kev->fflags;
1435 kn->kn_sdata = kev->data;
1436 kn->kn_kevent.ext[0] = kev->ext[0];
1437 kn->kn_kevent.ext[1] = kev->ext[1];
1438 }
1439
1440 /*
1441 * We can get here with kn->kn_knlist == NULL. This can happen when
1442 * the initial attach event decides that the event is "completed"
1443 * already. i.e. filt_procattach is called on a zombie process. It
1444 * will call filt_proc which will remove it from the list, and NULL
1445 * kn_knlist.
1446 */
1447 done_ev_add:
1448 if ((kev->flags & EV_DISABLE) &&
1449 ((kn->kn_status & KN_DISABLED) == 0)) {
1450 kn->kn_status |= KN_DISABLED;
1451 }
1452
1453 if ((kn->kn_status & KN_DISABLED) == 0 || (kev->flags & EV_ENABLE))
1454 event = kn->kn_fop->f_event(kn, 0);
1455 else
1456 event = 0;
1457 KQ_LOCK(kq);
1458 if (event)
1459 KNOTE_ACTIVATE(kn, 1);
1460 kn->kn_status &= ~(KN_INFLUX | KN_SCAN);
1461 KN_LIST_UNLOCK(kn);
1462 #ifdef KN_DEBUG
1463 #define IS_KN_DISABLED(kn) (!!(kn->kn_status & KN_DISABLED))
1464 #define IS_KN_QUEUED(kn) (!!(kn->kn_status & KN_QUEUED))
1465 #define IS_KN_ACTIVE(kn) (!!(kn->kn_status & KN_ACTIVE))
1466 if ((kev->flags & EV_ENABLE)) {
1467 printf("KN_DISABLED=%d KN_ACTIVE=%d KN_QUEUED=%d\n",
1468 IS_KN_DISABLED(kn), IS_KN_ACTIVE(kn), IS_KN_QUEUED(kn));
1469 }
1470 #endif
1471 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
1472 kn->kn_status &= ~KN_DISABLED;
1473 if ((kn->kn_status & KN_ACTIVE) &&
1474 ((kn->kn_status & KN_QUEUED) == 0))
1475 knote_enqueue(kn);
1476 }
1477 KQ_UNLOCK_FLUX(kq);
1478
1479 done:
1480 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1481 if (filedesc_unlock)
1482 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1483 if (fp != NULL)
1484 fdrop(fp, td);
1485 knote_free(tkn);
1486 if (fops != NULL)
1487 kqueue_fo_release(filt);
1488 return (error);
1489 }
1490
1491 static int
kqueue_acquire(struct file * fp,struct kqueue ** kqp)1492 kqueue_acquire(struct file *fp, struct kqueue **kqp)
1493 {
1494 int error;
1495 struct kqueue *kq;
1496
1497 error = 0;
1498
1499 kq = fp->f_data;
1500 if (fp->f_type != DTYPE_KQUEUE || kq == NULL)
1501 return (EBADF);
1502 *kqp = kq;
1503 KQ_LOCK(kq);
1504 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
1505 KQ_UNLOCK(kq);
1506 return (EBADF);
1507 }
1508 kq->kq_refcnt++;
1509 KQ_UNLOCK(kq);
1510
1511 return error;
1512 }
1513
1514 static void
kqueue_release(struct kqueue * kq,int locked)1515 kqueue_release(struct kqueue *kq, int locked)
1516 {
1517 if (locked)
1518 KQ_OWNED(kq);
1519 else
1520 KQ_LOCK(kq);
1521 kq->kq_refcnt--;
1522 if (kq->kq_refcnt == 1)
1523 wakeup(&kq->kq_refcnt);
1524 if (!locked)
1525 KQ_UNLOCK(kq);
1526 }
1527
1528 static void
kqueue_schedtask(struct kqueue * kq)1529 kqueue_schedtask(struct kqueue *kq)
1530 {
1531
1532 KQ_OWNED(kq);
1533 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
1534 ("scheduling kqueue task while draining"));
1535
1536 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
1537 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task);
1538 kq->kq_state |= KQ_TASKSCHED;
1539 }
1540 }
1541
1542 /*
1543 * Expand the kq to make sure we have storage for fops/ident pair.
1544 *
1545 * Return 0 on success (or no work necessary), return errno on failure.
1546 *
1547 * Not calling hashinit w/ waitok (proper malloc flag) should be safe.
1548 * If kqueue_register is called from a non-fd context, there usually/should
1549 * be no locks held.
1550 */
1551 static int
kqueue_expand(struct kqueue * kq,struct filterops * fops,uintptr_t ident,int waitok)1552 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident,
1553 int waitok)
1554 {
1555 struct klist *list, *tmp_knhash, *to_free;
1556 u_long tmp_knhashmask;
1557 int size;
1558 int fd;
1559 int mflag = waitok ? M_WAITOK : M_NOWAIT;
1560
1561 KQ_NOTOWNED(kq);
1562
1563 to_free = NULL;
1564 if (fops->f_isfd) {
1565 fd = ident;
1566 if (kq->kq_knlistsize <= fd) {
1567 size = kq->kq_knlistsize;
1568 while (size <= fd)
1569 size += KQEXTENT;
1570 list = malloc(size * sizeof(*list), M_KQUEUE, mflag);
1571 if (list == NULL)
1572 return ENOMEM;
1573 KQ_LOCK(kq);
1574 if (kq->kq_knlistsize > fd) {
1575 to_free = list;
1576 list = NULL;
1577 } else {
1578 if (kq->kq_knlist != NULL) {
1579 bcopy(kq->kq_knlist, list,
1580 kq->kq_knlistsize * sizeof(*list));
1581 to_free = kq->kq_knlist;
1582 kq->kq_knlist = NULL;
1583 }
1584 bzero((caddr_t)list +
1585 kq->kq_knlistsize * sizeof(*list),
1586 (size - kq->kq_knlistsize) * sizeof(*list));
1587 kq->kq_knlistsize = size;
1588 kq->kq_knlist = list;
1589 }
1590 KQ_UNLOCK(kq);
1591 }
1592 } else {
1593 if (kq->kq_knhashmask == 0) {
1594 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
1595 &tmp_knhashmask);
1596 if (tmp_knhash == NULL)
1597 return ENOMEM;
1598 KQ_LOCK(kq);
1599 if (kq->kq_knhashmask == 0) {
1600 kq->kq_knhash = tmp_knhash;
1601 kq->kq_knhashmask = tmp_knhashmask;
1602 } else {
1603 to_free = tmp_knhash;
1604 }
1605 KQ_UNLOCK(kq);
1606 }
1607 }
1608 free(to_free, M_KQUEUE);
1609
1610 KQ_NOTOWNED(kq);
1611 return 0;
1612 }
1613
1614 static void
kqueue_task(void * arg,int pending)1615 kqueue_task(void *arg, int pending)
1616 {
1617 struct kqueue *kq;
1618 int haskqglobal;
1619
1620 haskqglobal = 0;
1621 kq = arg;
1622
1623 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1624 KQ_LOCK(kq);
1625
1626 KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
1627
1628 kq->kq_state &= ~KQ_TASKSCHED;
1629 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
1630 wakeup(&kq->kq_state);
1631 }
1632 KQ_UNLOCK(kq);
1633 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1634 }
1635
1636 /*
1637 * Scan, update kn_data (if not ONESHOT), and copyout triggered events.
1638 * We treat KN_MARKER knotes as if they are INFLUX.
1639 */
1640 static int
kqueue_scan(struct kqueue * kq,int maxevents,struct kevent_copyops * k_ops,const struct timespec * tsp,struct kevent64_s * keva,struct thread * td)1641 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
1642 const struct timespec *tsp, struct kevent64_s *keva, struct thread *td)
1643 {
1644 struct kevent64_s *kevp;
1645 struct knote *kn, *marker;
1646 sbintime_t asbt, rsbt;
1647 int count, error, haskqglobal, influx, nkev, touch;
1648
1649 count = maxevents;
1650 nkev = 0;
1651 error = 0;
1652 haskqglobal = 0;
1653
1654 if (maxevents == 0)
1655 goto done_nl;
1656
1657 rsbt = 0;
1658 if (tsp != NULL) {
1659 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 ||
1660 tsp->tv_nsec >= 1000000000) {
1661 error = EINVAL;
1662 goto done_nl;
1663 }
1664 if (timespecisset(tsp)) {
1665 if (tsp->tv_sec <= INT32_MAX) {
1666 rsbt = tstosbt(*tsp);
1667 if (TIMESEL(&asbt, rsbt))
1668 asbt += tc_tick_sbt;
1669 if (asbt <= SBT_MAX - rsbt)
1670 asbt += rsbt;
1671 else
1672 asbt = 0;
1673 rsbt >>= tc_precexp;
1674 } else
1675 asbt = 0;
1676 } else
1677 asbt = -1;
1678 } else
1679 asbt = 0;
1680 marker = knote_alloc(1);
1681 marker->kn_status = KN_MARKER;
1682 KQ_LOCK(kq);
1683
1684 retry:
1685 kevp = keva;
1686 if (kq->kq_count == 0) {
1687 if (asbt == -1) {
1688 error = EWOULDBLOCK;
1689 } else {
1690 kq->kq_state |= KQ_SLEEP;
1691 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH,
1692 "kqread", asbt, rsbt, C_ABSOLUTE);
1693 }
1694 if (error == 0)
1695 goto retry;
1696 /* don't restart after signals... */
1697 if (error == ERESTART)
1698 error = EINTR;
1699 else if (error == EWOULDBLOCK)
1700 error = 0;
1701 goto done;
1702 }
1703
1704 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
1705 influx = 0;
1706 while (count) {
1707 KQ_OWNED(kq);
1708 kn = TAILQ_FIRST(&kq->kq_head);
1709
1710 if ((kn->kn_status == KN_MARKER && kn != marker) ||
1711 (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1712 if (influx) {
1713 influx = 0;
1714 KQ_FLUX_WAKEUP(kq);
1715 }
1716 kq->kq_state |= KQ_FLUXWAIT;
1717 error = msleep(kq, &kq->kq_lock, PSOCK,
1718 "kqflxwt", 0);
1719 continue;
1720 }
1721
1722 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
1723 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
1724 kn->kn_status &= ~KN_QUEUED;
1725 kq->kq_count--;
1726 continue;
1727 }
1728 if (kn == marker) {
1729 KQ_FLUX_WAKEUP(kq);
1730 if (count == maxevents)
1731 goto retry;
1732 goto done;
1733 }
1734 KASSERT((kn->kn_status & KN_INFLUX) == 0,
1735 ("KN_INFLUX set when not suppose to be"));
1736
1737 if ((kn->kn_flags & EV_DROP) == EV_DROP) {
1738 kn->kn_status &= ~KN_QUEUED;
1739 kn->kn_status |= KN_INFLUX;
1740 kq->kq_count--;
1741 KQ_UNLOCK(kq);
1742 /*
1743 * We don't need to lock the list since we've marked
1744 * it _INFLUX.
1745 */
1746 if (!(kn->kn_status & KN_DETACHED))
1747 kn->kn_fop->f_detach(kn);
1748 knote_drop(kn, td);
1749 KQ_LOCK(kq);
1750 continue;
1751 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
1752 kn->kn_status &= ~KN_QUEUED;
1753 kn->kn_status |= KN_INFLUX;
1754 kq->kq_count--;
1755 KQ_UNLOCK(kq);
1756 /*
1757 * We don't need to lock the list since we've marked
1758 * it _INFLUX.
1759 */
1760 *kevp = kn->kn_kevent;
1761 if (!(kn->kn_status & KN_DETACHED))
1762 kn->kn_fop->f_detach(kn);
1763 knote_drop(kn, td);
1764 KQ_LOCK(kq);
1765 kn = NULL;
1766 } else {
1767 kn->kn_status |= KN_INFLUX | KN_SCAN;
1768 KQ_UNLOCK(kq);
1769 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
1770 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1771 KN_LIST_LOCK(kn);
1772 if (kn->kn_fop->f_event(kn, 0) == 0) {
1773 KQ_LOCK(kq);
1774 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1775 kn->kn_status &=
1776 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX |
1777 KN_SCAN);
1778 kq->kq_count--;
1779 KN_LIST_UNLOCK(kn);
1780 influx = 1;
1781 continue;
1782 }
1783 touch = (!kn->kn_fop->f_isfd &&
1784 kn->kn_fop->f_touch != NULL);
1785 if (touch)
1786 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS);
1787 else
1788 *kevp = kn->kn_kevent;
1789 KQ_LOCK(kq);
1790 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1791 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
1792 /*
1793 * Manually clear knotes who weren't
1794 * 'touch'ed.
1795 */
1796 if (touch == 0 && kn->kn_flags & EV_CLEAR) {
1797 kn->kn_data = 0;
1798 kn->kn_fflags = 0;
1799 }
1800 if (kn->kn_flags & EV_DISPATCH)
1801 kn->kn_status |= KN_DISABLED;
1802 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
1803 kq->kq_count--;
1804 } else
1805 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
1806
1807 kn->kn_status &= ~(KN_INFLUX | KN_SCAN);
1808 KN_LIST_UNLOCK(kn);
1809 influx = 1;
1810 }
1811
1812 /* we are returning a copy to the user */
1813 kevp++;
1814 nkev++;
1815 count--;
1816
1817 if (nkev == KQ_NEVENTS) {
1818 influx = 0;
1819 KQ_UNLOCK_FLUX(kq);
1820 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1821 nkev = 0;
1822 kevp = keva;
1823 KQ_LOCK(kq);
1824 if (error)
1825 break;
1826 }
1827 }
1828 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
1829 done:
1830 KQ_OWNED(kq);
1831 KQ_UNLOCK_FLUX(kq);
1832 knote_free(marker);
1833 done_nl:
1834 KQ_NOTOWNED(kq);
1835 if (nkev != 0)
1836 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1837 td->td_retval[0] = maxevents - count;
1838 return (error);
1839 }
1840
1841 /*ARGSUSED*/
1842 static int
kqueue_ioctl(struct file * fp,u_long cmd,void * data,struct ucred * active_cred,struct thread * td)1843 kqueue_ioctl(struct file *fp, u_long cmd, void *data,
1844 struct ucred *active_cred, struct thread *td)
1845 {
1846 /*
1847 * Enabling sigio causes two major problems:
1848 * 1) infinite recursion:
1849 * Synopsys: kevent is being used to track signals and have FIOASYNC
1850 * set. On receipt of a signal this will cause a kqueue to recurse
1851 * into itself over and over. Sending the sigio causes the kqueue
1852 * to become ready, which in turn posts sigio again, forever.
1853 * Solution: this can be solved by setting a flag in the kqueue that
1854 * we have a SIGIO in progress.
1855 * 2) locking problems:
1856 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
1857 * us above the proc and pgrp locks.
1858 * Solution: Post a signal using an async mechanism, being sure to
1859 * record a generation count in the delivery so that we do not deliver
1860 * a signal to the wrong process.
1861 *
1862 * Note, these two mechanisms are somewhat mutually exclusive!
1863 */
1864 #if 0
1865 struct kqueue *kq;
1866
1867 kq = fp->f_data;
1868 switch (cmd) {
1869 case FIOASYNC:
1870 if (*(int *)data) {
1871 kq->kq_state |= KQ_ASYNC;
1872 } else {
1873 kq->kq_state &= ~KQ_ASYNC;
1874 }
1875 return (0);
1876
1877 case FIOSETOWN:
1878 return (fsetown(*(int *)data, &kq->kq_sigio));
1879
1880 case FIOGETOWN:
1881 *(int *)data = fgetown(&kq->kq_sigio);
1882 return (0);
1883 }
1884 #endif
1885
1886 return (ENOTTY);
1887 }
1888
1889 /*ARGSUSED*/
1890 static int
kqueue_poll(struct file * fp,int events,struct ucred * active_cred,struct thread * td)1891 kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
1892 struct thread *td)
1893 {
1894 struct kqueue *kq;
1895 int revents = 0;
1896 int error;
1897
1898 if ((error = kqueue_acquire(fp, &kq)))
1899 return POLLERR;
1900
1901 KQ_LOCK(kq);
1902 if (events & (POLLIN | POLLRDNORM)) {
1903 if (kq->kq_count) {
1904 revents |= events & (POLLIN | POLLRDNORM);
1905 } else {
1906 selrecord(td, &kq->kq_sel);
1907 if (SEL_WAITING(&kq->kq_sel))
1908 kq->kq_state |= KQ_SEL;
1909 }
1910 }
1911 kqueue_release(kq, 1);
1912 KQ_UNLOCK(kq);
1913 return (revents);
1914 }
1915
1916 /*ARGSUSED*/
1917 static int
kqueue_stat(struct file * fp,struct stat * st,struct ucred * active_cred,struct thread * td)1918 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
1919 struct thread *td)
1920 {
1921
1922 bzero((void *)st, sizeof *st);
1923 /*
1924 * We no longer return kq_count because the unlocked value is useless.
1925 * If you spent all this time getting the count, why not spend your
1926 * syscall better by calling kevent?
1927 *
1928 * XXX - This is needed for libc_r.
1929 */
1930 st->st_mode = S_IFIFO;
1931 return (0);
1932 }
1933
1934 static void
kqueue_drain(struct kqueue * kq,struct thread * td)1935 kqueue_drain(struct kqueue *kq, struct thread *td)
1936 {
1937 struct knote *kn;
1938 int i;
1939
1940 KQ_LOCK(kq);
1941
1942 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
1943 ("kqueue already closing"));
1944 kq->kq_state |= KQ_CLOSING;
1945 if (kq->kq_refcnt > 1)
1946 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
1947
1948 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
1949
1950 KASSERT(knlist_empty(&kq->kq_sel.si_note),
1951 ("kqueue's knlist not empty"));
1952
1953 for (i = 0; i < kq->kq_knlistsize; i++) {
1954 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
1955 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1956 kq->kq_state |= KQ_FLUXWAIT;
1957 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
1958 continue;
1959 }
1960 kn->kn_status |= KN_INFLUX;
1961 KQ_UNLOCK(kq);
1962 if (!(kn->kn_status & KN_DETACHED))
1963 kn->kn_fop->f_detach(kn);
1964 knote_drop(kn, td);
1965 KQ_LOCK(kq);
1966 }
1967 }
1968 if (kq->kq_knhashmask != 0) {
1969 for (i = 0; i <= kq->kq_knhashmask; i++) {
1970 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
1971 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1972 kq->kq_state |= KQ_FLUXWAIT;
1973 msleep(kq, &kq->kq_lock, PSOCK,
1974 "kqclo2", 0);
1975 continue;
1976 }
1977 kn->kn_status |= KN_INFLUX;
1978 KQ_UNLOCK(kq);
1979 if (!(kn->kn_status & KN_DETACHED))
1980 kn->kn_fop->f_detach(kn);
1981 knote_drop(kn, td);
1982 KQ_LOCK(kq);
1983 }
1984 }
1985 }
1986
1987 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
1988 kq->kq_state |= KQ_TASKDRAIN;
1989 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
1990 }
1991
1992 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
1993 selwakeuppri(&kq->kq_sel, PSOCK);
1994 if (!SEL_WAITING(&kq->kq_sel))
1995 kq->kq_state &= ~KQ_SEL;
1996 }
1997
1998 KQ_UNLOCK(kq);
1999 }
2000
2001 static void
kqueue_destroy(struct kqueue * kq)2002 kqueue_destroy(struct kqueue *kq)
2003 {
2004
2005 KASSERT(kq->kq_fdp == NULL,
2006 ("kqueue still attached to a file descriptor"));
2007 seldrain(&kq->kq_sel);
2008 knlist_destroy(&kq->kq_sel.si_note);
2009 mtx_destroy(&kq->kq_lock);
2010
2011 if (kq->kq_knhash != NULL)
2012 free(kq->kq_knhash, M_KQUEUE);
2013 if (kq->kq_knlist != NULL)
2014 free(kq->kq_knlist, M_KQUEUE);
2015
2016 funsetown(&kq->kq_sigio);
2017 }
2018
2019 /*ARGSUSED*/
2020 static int
kqueue_close(struct file * fp,struct thread * td)2021 kqueue_close(struct file *fp, struct thread *td)
2022 {
2023 struct kqueue *kq = fp->f_data;
2024 struct filedesc *fdp;
2025 int error;
2026 int filedesc_unlock;
2027
2028 if ((error = kqueue_acquire(fp, &kq)))
2029 return error;
2030 kqueue_drain(kq, td);
2031
2032 /*
2033 * We could be called due to the knote_drop() doing fdrop(),
2034 * called from kqueue_register(). In this case the global
2035 * lock is owned, and filedesc sx is locked before, to not
2036 * take the sleepable lock after non-sleepable.
2037 */
2038 fdp = kq->kq_fdp;
2039 kq->kq_fdp = NULL;
2040 if (!sx_xlocked(FILEDESC_LOCK(fdp))) {
2041 FILEDESC_XLOCK(fdp);
2042 filedesc_unlock = 1;
2043 } else
2044 filedesc_unlock = 0;
2045 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list);
2046 if (filedesc_unlock)
2047 FILEDESC_XUNLOCK(fdp);
2048
2049 kqueue_destroy(kq);
2050 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0);
2051 crfree(kq->kq_cred);
2052 free(kq, M_KQUEUE);
2053 fp->f_data = NULL;
2054
2055 return (0);
2056 }
2057
2058 static int
kqueue_fill_kinfo(struct file * fp,struct kinfo_file * kif,struct filedesc * fdp)2059 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
2060 {
2061
2062 kif->kf_type = KF_TYPE_KQUEUE;
2063 return (0);
2064 }
2065
2066 static void
kqueue_wakeup(struct kqueue * kq)2067 kqueue_wakeup(struct kqueue *kq)
2068 {
2069 KQ_OWNED(kq);
2070
2071 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
2072 kq->kq_state &= ~KQ_SLEEP;
2073 wakeup(kq);
2074 }
2075 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
2076 selwakeuppri(&kq->kq_sel, PSOCK);
2077 if (!SEL_WAITING(&kq->kq_sel))
2078 kq->kq_state &= ~KQ_SEL;
2079 }
2080 if (!knlist_empty(&kq->kq_sel.si_note))
2081 kqueue_schedtask(kq);
2082 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
2083 pgsigio(&kq->kq_sigio, SIGIO, 0);
2084 }
2085 }
2086
2087 /*
2088 * Walk down a list of knotes, activating them if their event has triggered.
2089 *
2090 * There is a possibility to optimize in the case of one kq watching another.
2091 * Instead of scheduling a task to wake it up, you could pass enough state
2092 * down the chain to make up the parent kqueue. Make this code functional
2093 * first.
2094 */
2095 void
knote(struct knlist * list,long hint,int lockflags)2096 knote(struct knlist *list, long hint, int lockflags)
2097 {
2098 struct kqueue *kq;
2099 struct knote *kn, *tkn;
2100 int error;
2101
2102 if (list == NULL)
2103 return;
2104
2105 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
2106
2107 if ((lockflags & KNF_LISTLOCKED) == 0)
2108 KNL_LOCK(list);
2109
2110 /*
2111 * If we unlock the list lock (and set KN_INFLUX), we can
2112 * eliminate the kqueue scheduling, but this will introduce
2113 * four lock/unlock's for each knote to test. Also, marker
2114 * would be needed to keep iteration position, since filters
2115 * or other threads could remove events.
2116 */
2117 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) {
2118 kq = kn->kn_kq;
2119 KQ_LOCK(kq);
2120 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) {
2121 /*
2122 * Do not process the influx notes, except for
2123 * the influx coming from the kq unlock in the
2124 * kqueue_scan(). In the later case, we do
2125 * not interfere with the scan, since the code
2126 * fragment in kqueue_scan() locks the knlist,
2127 * and cannot proceed until we finished.
2128 */
2129 KQ_UNLOCK(kq);
2130 } else if ((lockflags & KNF_NOKQLOCK) != 0) {
2131 kn->kn_status |= KN_INFLUX;
2132 KQ_UNLOCK(kq);
2133 error = kn->kn_fop->f_event(kn, hint);
2134 KQ_LOCK(kq);
2135 kn->kn_status &= ~KN_INFLUX;
2136 if (error)
2137 KNOTE_ACTIVATE(kn, 1);
2138 KQ_UNLOCK_FLUX(kq);
2139 } else {
2140 kn->kn_status |= KN_HASKQLOCK;
2141 if (kn->kn_fop->f_event(kn, hint))
2142 KNOTE_ACTIVATE(kn, 1);
2143 kn->kn_status &= ~KN_HASKQLOCK;
2144 KQ_UNLOCK(kq);
2145 }
2146 }
2147 if ((lockflags & KNF_LISTLOCKED) == 0)
2148 list->kl_unlock(list->kl_lockarg);
2149 }
2150
2151 /*
2152 * add a knote to a knlist
2153 */
2154 void
knlist_add(struct knlist * knl,struct knote * kn,int islocked)2155 knlist_add(struct knlist *knl, struct knote *kn, int islocked)
2156 {
2157 KNL_ASSERT_LOCK(knl, islocked);
2158 KQ_NOTOWNED(kn->kn_kq);
2159 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) ==
2160 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED"));
2161 if (!islocked)
2162 KNL_LOCK(knl);
2163 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext);
2164 if (!islocked)
2165 knl->kl_unlock(knl->kl_lockarg);
2166 KQ_LOCK(kn->kn_kq);
2167 kn->kn_knlist = knl;
2168 kn->kn_status &= ~KN_DETACHED;
2169 KQ_UNLOCK(kn->kn_kq);
2170 }
2171
2172 static void
knlist_remove_kq(struct knlist * knl,struct knote * kn,int knlislocked,int kqislocked)2173 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked)
2174 {
2175 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked"));
2176 KNL_ASSERT_LOCK(knl, knlislocked);
2177 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED);
2178 if (!kqislocked)
2179 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX,
2180 ("knlist_remove called w/o knote being KN_INFLUX or already removed"));
2181 if (!knlislocked)
2182 KNL_LOCK(knl);
2183 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
2184 kn->kn_knlist = NULL;
2185 if (!knlislocked)
2186 knl->kl_unlock(knl->kl_lockarg);
2187 if (!kqislocked)
2188 KQ_LOCK(kn->kn_kq);
2189 kn->kn_status |= KN_DETACHED;
2190 if (!kqislocked)
2191 KQ_UNLOCK(kn->kn_kq);
2192 }
2193
2194 /*
2195 * remove knote from the specified knlist
2196 */
2197 void
knlist_remove(struct knlist * knl,struct knote * kn,int islocked)2198 knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
2199 {
2200
2201 knlist_remove_kq(knl, kn, islocked, 0);
2202 }
2203
2204 /*
2205 * remove knote from the specified knlist while in f_event handler.
2206 */
2207 void
knlist_remove_inevent(struct knlist * knl,struct knote * kn)2208 knlist_remove_inevent(struct knlist *knl, struct knote *kn)
2209 {
2210
2211 knlist_remove_kq(knl, kn, 1,
2212 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK);
2213 }
2214
2215 int
knlist_empty(struct knlist * knl)2216 knlist_empty(struct knlist *knl)
2217 {
2218
2219 KNL_ASSERT_LOCKED(knl);
2220 return SLIST_EMPTY(&knl->kl_list);
2221 }
2222
2223 static struct mtx knlist_lock;
2224 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects",
2225 MTX_DEF);
2226
2227 static void
knlist_mtx_lock(void * arg,char * file,int line)2228 knlist_mtx_lock(void *arg, char *file, int line)
2229 {
2230
2231 _mtx_lock_flags((struct mtx *)arg, 0, file, line);
2232 }
2233
2234 static void
knlist_mtx_unlock(void * arg)2235 knlist_mtx_unlock(void *arg)
2236 {
2237
2238 mtx_unlock((struct mtx *)arg);
2239 }
2240
2241 static void
knlist_mtx_assert_locked(void * arg)2242 knlist_mtx_assert_locked(void *arg)
2243 {
2244
2245 mtx_assert((struct mtx *)arg, MA_OWNED);
2246 }
2247
2248 static void
knlist_mtx_assert_unlocked(void * arg)2249 knlist_mtx_assert_unlocked(void *arg)
2250 {
2251
2252 mtx_assert((struct mtx *)arg, MA_NOTOWNED);
2253 }
2254
2255 static void
knlist_rw_rlock(void * arg,char * file,int line)2256 knlist_rw_rlock(void *arg, char *file, int line)
2257 {
2258
2259 _rw_rlock((struct rwlock *)arg, file, line);
2260 }
2261
2262 static void
knlist_rw_runlock(void * arg)2263 knlist_rw_runlock(void *arg)
2264 {
2265
2266 rw_runlock((struct rwlock *)arg);
2267 }
2268
2269 static void
knlist_rw_assert_locked(void * arg)2270 knlist_rw_assert_locked(void *arg)
2271 {
2272
2273 rw_assert((struct rwlock *)arg, RA_LOCKED);
2274 }
2275
2276 static void
knlist_rw_assert_unlocked(void * arg)2277 knlist_rw_assert_unlocked(void *arg)
2278 {
2279
2280 rw_assert((struct rwlock *)arg, RA_UNLOCKED);
2281 }
2282
2283 void
knlist_init(struct knlist * knl,void * lock,void (* kl_lock)(void *,char *,int),void (* kl_unlock)(void *),void (* kl_assert_locked)(void *),void (* kl_assert_unlocked)(void *))2284 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *, char *, int),
2285 void (*kl_unlock)(void *),
2286 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *))
2287 {
2288
2289 if (lock == NULL)
2290 knl->kl_lockarg = &knlist_lock;
2291 else
2292 knl->kl_lockarg = lock;
2293
2294 if (kl_lock == NULL)
2295 knl->kl_lock = knlist_mtx_lock;
2296 else
2297 knl->kl_lock = kl_lock;
2298 if (kl_unlock == NULL)
2299 knl->kl_unlock = knlist_mtx_unlock;
2300 else
2301 knl->kl_unlock = kl_unlock;
2302 if (kl_assert_locked == NULL)
2303 knl->kl_assert_locked = knlist_mtx_assert_locked;
2304 else
2305 knl->kl_assert_locked = kl_assert_locked;
2306 if (kl_assert_unlocked == NULL)
2307 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked;
2308 else
2309 knl->kl_assert_unlocked = kl_assert_unlocked;
2310
2311 SLIST_INIT(&knl->kl_list);
2312 }
2313
2314 void
knlist_init_mtx(struct knlist * knl,struct mtx * lock)2315 knlist_init_mtx(struct knlist *knl, struct mtx *lock)
2316 {
2317
2318 knlist_init(knl, lock, NULL, NULL, NULL, NULL);
2319 }
2320
2321 void
knlist_init_rw_reader(struct knlist * knl,struct rwlock * lock)2322 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock)
2323 {
2324
2325 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock,
2326 knlist_rw_assert_locked, knlist_rw_assert_unlocked);
2327 }
2328
2329 void
knlist_destroy(struct knlist * knl)2330 knlist_destroy(struct knlist *knl)
2331 {
2332
2333 #ifdef INVARIANTS
2334 /*
2335 * if we run across this error, we need to find the offending
2336 * driver and have it call knlist_clear or knlist_delete.
2337 */
2338 if (!SLIST_EMPTY(&knl->kl_list))
2339 printf("WARNING: destroying knlist w/ knotes on it!\n");
2340 #endif
2341
2342 knl->kl_lock = NULL;
2343 knl->kl_lockarg = knl->kl_unlock = NULL;
2344 SLIST_INIT(&knl->kl_list);
2345 }
2346
2347 /*
2348 * Even if we are locked, we may need to drop the lock to allow any influx
2349 * knotes time to "settle".
2350 */
2351 void
knlist_cleardel(struct knlist * knl,struct thread * td,int islocked,int killkn)2352 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
2353 {
2354 struct knote *kn, *kn2;
2355 struct kqueue *kq;
2356
2357 if (islocked)
2358 KNL_ASSERT_LOCKED(knl);
2359 else {
2360 KNL_ASSERT_UNLOCKED(knl);
2361 again: /* need to reacquire lock since we have dropped it */
2362 KNL_LOCK(knl);
2363 }
2364
2365 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
2366 kq = kn->kn_kq;
2367 KQ_LOCK(kq);
2368 if ((kn->kn_status & KN_INFLUX)) {
2369 KQ_UNLOCK(kq);
2370 continue;
2371 }
2372 knlist_remove_kq(knl, kn, 1, 1);
2373 if (killkn) {
2374 kn->kn_status |= KN_INFLUX | KN_DETACHED;
2375 KQ_UNLOCK(kq);
2376 knote_drop(kn, td);
2377 } else {
2378 /* Make sure cleared knotes disappear soon */
2379 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
2380 KQ_UNLOCK(kq);
2381 }
2382 kq = NULL;
2383 }
2384
2385 if (!SLIST_EMPTY(&knl->kl_list)) {
2386 /* there are still KN_INFLUX remaining */
2387 kn = SLIST_FIRST(&knl->kl_list);
2388 kq = kn->kn_kq;
2389 KQ_LOCK(kq);
2390 KASSERT(kn->kn_status & KN_INFLUX,
2391 ("knote removed w/o list lock"));
2392 knl->kl_unlock(knl->kl_lockarg);
2393 kq->kq_state |= KQ_FLUXWAIT;
2394 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
2395 kq = NULL;
2396 goto again;
2397 }
2398
2399 if (islocked)
2400 KNL_ASSERT_LOCKED(knl);
2401 else {
2402 knl->kl_unlock(knl->kl_lockarg);
2403 KNL_ASSERT_UNLOCKED(knl);
2404 }
2405 }
2406
2407 /*
2408 * Remove all knotes referencing a specified fd must be called with FILEDESC
2409 * lock. This prevents a race where a new fd comes along and occupies the
2410 * entry and we attach a knote to the fd.
2411 */
2412 void
knote_fdclose(struct thread * td,int fd)2413 knote_fdclose(struct thread *td, int fd)
2414 {
2415 struct filedesc *fdp = td->td_proc->p_fd;
2416 struct kqueue *kq;
2417 struct knote *kn;
2418 int influx;
2419
2420 FILEDESC_XLOCK_ASSERT(fdp);
2421
2422 /*
2423 * We shouldn't have to worry about new kevents appearing on fd
2424 * since filedesc is locked.
2425 */
2426 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
2427 KQ_LOCK(kq);
2428
2429 again:
2430 influx = 0;
2431 while (kq->kq_knlistsize > fd &&
2432 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
2433 if (kn->kn_status & KN_INFLUX) {
2434 /* someone else might be waiting on our knote */
2435 if (influx)
2436 wakeup(kq);
2437 kq->kq_state |= KQ_FLUXWAIT;
2438 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
2439 goto again;
2440 }
2441 kn->kn_status |= KN_INFLUX;
2442 KQ_UNLOCK(kq);
2443 if (!(kn->kn_status & KN_DETACHED))
2444 kn->kn_fop->f_detach(kn);
2445 knote_drop(kn, td);
2446 influx = 1;
2447 KQ_LOCK(kq);
2448 }
2449 KQ_UNLOCK_FLUX(kq);
2450 }
2451 }
2452
2453 static int
knote_attach(struct knote * kn,struct kqueue * kq)2454 knote_attach(struct knote *kn, struct kqueue *kq)
2455 {
2456 struct klist *list;
2457
2458 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX"));
2459 KQ_OWNED(kq);
2460
2461 if (kn->kn_fop->f_isfd) {
2462 if (kn->kn_id >= kq->kq_knlistsize)
2463 return ENOMEM;
2464 list = &kq->kq_knlist[kn->kn_id];
2465 } else {
2466 if (kq->kq_knhash == NULL)
2467 return ENOMEM;
2468 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2469 }
2470
2471 SLIST_INSERT_HEAD(list, kn, kn_link);
2472
2473 return 0;
2474 }
2475
2476 /*
2477 * knote must already have been detached using the f_detach method.
2478 * no lock need to be held, it is assumed that the KN_INFLUX flag is set
2479 * to prevent other removal.
2480 */
2481 static void
knote_drop(struct knote * kn,struct thread * td)2482 knote_drop(struct knote *kn, struct thread *td)
2483 {
2484 struct kqueue *kq;
2485 struct klist *list;
2486
2487 kq = kn->kn_kq;
2488
2489 KQ_NOTOWNED(kq);
2490 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX,
2491 ("knote_drop called without KN_INFLUX set in kn_status"));
2492
2493 KQ_LOCK(kq);
2494 if (kn->kn_fop->f_isfd)
2495 list = &kq->kq_knlist[kn->kn_id];
2496 else
2497 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2498
2499 if (!SLIST_EMPTY(list))
2500 SLIST_REMOVE(list, kn, knote, kn_link);
2501 if (kn->kn_status & KN_QUEUED)
2502 knote_dequeue(kn);
2503 KQ_UNLOCK_FLUX(kq);
2504
2505 if (kn->kn_fop->f_isfd) {
2506 fdrop(kn->kn_fp, td);
2507 kn->kn_fp = NULL;
2508 }
2509 kqueue_fo_release(kn->kn_kevent.filter);
2510 kn->kn_fop = NULL;
2511 knote_free(kn);
2512 }
2513
2514 void
knote_enqueue(struct knote * kn)2515 knote_enqueue(struct knote *kn)
2516 {
2517 struct kqueue *kq = kn->kn_kq;
2518
2519 KQ_OWNED(kn->kn_kq);
2520 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
2521
2522 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
2523 kn->kn_status |= KN_QUEUED;
2524 kq->kq_count++;
2525 kqueue_wakeup(kq);
2526 }
2527
2528 static void
knote_dequeue(struct knote * kn)2529 knote_dequeue(struct knote *kn)
2530 {
2531 struct kqueue *kq = kn->kn_kq;
2532
2533 KQ_OWNED(kn->kn_kq);
2534 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
2535
2536 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
2537 kn->kn_status &= ~KN_QUEUED;
2538 kq->kq_count--;
2539 }
2540
2541 static void
knote_init(void)2542 knote_init(void)
2543 {
2544
2545 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
2546 NULL, NULL, UMA_ALIGN_PTR, 0);
2547 }
2548 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
2549
2550 static struct knote *
knote_alloc(int waitok)2551 knote_alloc(int waitok)
2552 {
2553
2554 return (uma_zalloc(knote_zone, (waitok ? M_WAITOK : M_NOWAIT) |
2555 M_ZERO));
2556 }
2557
2558 static void
knote_free(struct knote * kn)2559 knote_free(struct knote *kn)
2560 {
2561
2562 uma_zfree(knote_zone, kn);
2563 }
2564
2565 /*
2566 * Register the kev w/ the kq specified by fd.
2567 */
2568 int
kqfd_register(int fd,struct kevent64_s * kev,struct thread * td,int waitok)2569 kqfd_register(int fd, struct kevent64_s *kev, struct thread *td, int waitok)
2570 {
2571 struct kqueue *kq;
2572 struct file *fp;
2573 cap_rights_t rights;
2574 int error;
2575
2576 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp);
2577 if (error != 0)
2578 return (error);
2579 if ((error = kqueue_acquire(fp, &kq)) != 0)
2580 goto noacquire;
2581
2582 error = kqueue_register(kq, kev, td, waitok);
2583
2584 kqueue_release(kq, 0);
2585
2586 noacquire:
2587 fdrop(fp, td);
2588
2589 return error;
2590 }
2591