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