FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_event.c
1 /*-
2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
3 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org>
4 * Copyright (c) 2009 Apple, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD: releng/11.2/sys/kern/kern_event.c 342899 2019-01-09 18:57:38Z emaste $");
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 int filt_timer(struct knote *kn, long hint);
155 static int filt_userattach(struct knote *kn);
156 static void filt_userdetach(struct knote *kn);
157 static int filt_user(struct knote *kn, long hint);
158 static void filt_usertouch(struct knote *kn, struct kevent *kev,
159 u_long type);
160
161 static struct filterops file_filtops = {
162 .f_isfd = 1,
163 .f_attach = filt_fileattach,
164 };
165 static struct filterops kqread_filtops = {
166 .f_isfd = 1,
167 .f_detach = filt_kqdetach,
168 .f_event = filt_kqueue,
169 };
170 /* XXX - move to kern_proc.c? */
171 static struct filterops proc_filtops = {
172 .f_isfd = 0,
173 .f_attach = filt_procattach,
174 .f_detach = filt_procdetach,
175 .f_event = filt_proc,
176 };
177 static struct filterops timer_filtops = {
178 .f_isfd = 0,
179 .f_attach = filt_timerattach,
180 .f_detach = filt_timerdetach,
181 .f_event = filt_timer,
182 };
183 static struct filterops user_filtops = {
184 .f_attach = filt_userattach,
185 .f_detach = filt_userdetach,
186 .f_event = filt_user,
187 .f_touch = filt_usertouch,
188 };
189
190 static uma_zone_t knote_zone;
191 static unsigned int kq_ncallouts = 0;
192 static unsigned int kq_calloutmax = 4 * 1024;
193 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
194 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
195
196 /* XXX - ensure not KN_INFLUX?? */
197 #define KNOTE_ACTIVATE(kn, islock) do { \
198 if ((islock)) \
199 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \
200 else \
201 KQ_LOCK((kn)->kn_kq); \
202 (kn)->kn_status |= KN_ACTIVE; \
203 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
204 knote_enqueue((kn)); \
205 if (!(islock)) \
206 KQ_UNLOCK((kn)->kn_kq); \
207 } while(0)
208 #define KQ_LOCK(kq) do { \
209 mtx_lock(&(kq)->kq_lock); \
210 } while (0)
211 #define KQ_FLUX_WAKEUP(kq) do { \
212 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \
213 (kq)->kq_state &= ~KQ_FLUXWAIT; \
214 wakeup((kq)); \
215 } \
216 } while (0)
217 #define KQ_UNLOCK_FLUX(kq) do { \
218 KQ_FLUX_WAKEUP(kq); \
219 mtx_unlock(&(kq)->kq_lock); \
220 } while (0)
221 #define KQ_UNLOCK(kq) do { \
222 mtx_unlock(&(kq)->kq_lock); \
223 } while (0)
224 #define KQ_OWNED(kq) do { \
225 mtx_assert(&(kq)->kq_lock, MA_OWNED); \
226 } while (0)
227 #define KQ_NOTOWNED(kq) do { \
228 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \
229 } while (0)
230
231 static struct knlist *
232 kn_list_lock(struct knote *kn)
233 {
234 struct knlist *knl;
235
236 knl = kn->kn_knlist;
237 if (knl != NULL)
238 knl->kl_lock(knl->kl_lockarg);
239 return (knl);
240 }
241
242 static void
243 kn_list_unlock(struct knlist *knl)
244 {
245 bool do_free;
246
247 if (knl == NULL)
248 return;
249 do_free = knl->kl_autodestroy && knlist_empty(knl);
250 knl->kl_unlock(knl->kl_lockarg);
251 if (do_free) {
252 knlist_destroy(knl);
253 free(knl, M_KQUEUE);
254 }
255 }
256
257 #define KNL_ASSERT_LOCK(knl, islocked) do { \
258 if (islocked) \
259 KNL_ASSERT_LOCKED(knl); \
260 else \
261 KNL_ASSERT_UNLOCKED(knl); \
262 } while (0)
263 #ifdef INVARIANTS
264 #define KNL_ASSERT_LOCKED(knl) do { \
265 knl->kl_assert_locked((knl)->kl_lockarg); \
266 } while (0)
267 #define KNL_ASSERT_UNLOCKED(knl) do { \
268 knl->kl_assert_unlocked((knl)->kl_lockarg); \
269 } while (0)
270 #else /* !INVARIANTS */
271 #define KNL_ASSERT_LOCKED(knl) do {} while(0)
272 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
273 #endif /* INVARIANTS */
274
275 #ifndef KN_HASHSIZE
276 #define KN_HASHSIZE 64 /* XXX should be tunable */
277 #endif
278
279 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
280
281 static int
282 filt_nullattach(struct knote *kn)
283 {
284
285 return (ENXIO);
286 };
287
288 struct filterops null_filtops = {
289 .f_isfd = 0,
290 .f_attach = filt_nullattach,
291 };
292
293 /* XXX - make SYSINIT to add these, and move into respective modules. */
294 extern struct filterops sig_filtops;
295 extern struct filterops fs_filtops;
296
297 /*
298 * Table for for all system-defined filters.
299 */
300 static struct mtx filterops_lock;
301 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops",
302 MTX_DEF);
303 static struct {
304 struct filterops *for_fop;
305 int for_nolock;
306 int for_refcnt;
307 } sysfilt_ops[EVFILT_SYSCOUNT] = {
308 { &file_filtops, 1 }, /* EVFILT_READ */
309 { &file_filtops, 1 }, /* EVFILT_WRITE */
310 { &null_filtops }, /* EVFILT_AIO */
311 { &file_filtops, 1 }, /* EVFILT_VNODE */
312 { &proc_filtops, 1 }, /* EVFILT_PROC */
313 { &sig_filtops, 1 }, /* EVFILT_SIGNAL */
314 { &timer_filtops, 1 }, /* EVFILT_TIMER */
315 { &file_filtops, 1 }, /* EVFILT_PROCDESC */
316 { &fs_filtops, 1 }, /* EVFILT_FS */
317 { &null_filtops }, /* EVFILT_LIO */
318 { &user_filtops, 1 }, /* EVFILT_USER */
319 { &null_filtops }, /* EVFILT_SENDFILE */
320 };
321
322 /*
323 * Simple redirection for all cdevsw style objects to call their fo_kqfilter
324 * method.
325 */
326 static int
327 filt_fileattach(struct knote *kn)
328 {
329
330 return (fo_kqfilter(kn->kn_fp, kn));
331 }
332
333 /*ARGSUSED*/
334 static int
335 kqueue_kqfilter(struct file *fp, struct knote *kn)
336 {
337 struct kqueue *kq = kn->kn_fp->f_data;
338
339 if (kn->kn_filter != EVFILT_READ)
340 return (EINVAL);
341
342 kn->kn_status |= KN_KQUEUE;
343 kn->kn_fop = &kqread_filtops;
344 knlist_add(&kq->kq_sel.si_note, kn, 0);
345
346 return (0);
347 }
348
349 static void
350 filt_kqdetach(struct knote *kn)
351 {
352 struct kqueue *kq = kn->kn_fp->f_data;
353
354 knlist_remove(&kq->kq_sel.si_note, kn, 0);
355 }
356
357 /*ARGSUSED*/
358 static int
359 filt_kqueue(struct knote *kn, long hint)
360 {
361 struct kqueue *kq = kn->kn_fp->f_data;
362
363 kn->kn_data = kq->kq_count;
364 return (kn->kn_data > 0);
365 }
366
367 /* XXX - move to kern_proc.c? */
368 static int
369 filt_procattach(struct knote *kn)
370 {
371 struct proc *p;
372 int error;
373 bool exiting, immediate;
374
375 exiting = immediate = false;
376 p = pfind(kn->kn_id);
377 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
378 p = zpfind(kn->kn_id);
379 exiting = true;
380 } else if (p != NULL && (p->p_flag & P_WEXIT)) {
381 exiting = true;
382 }
383
384 if (p == NULL)
385 return (ESRCH);
386 if ((error = p_cansee(curthread, p))) {
387 PROC_UNLOCK(p);
388 return (error);
389 }
390
391 kn->kn_ptr.p_proc = p;
392 kn->kn_flags |= EV_CLEAR; /* automatically set */
393
394 /*
395 * Internal flag indicating registration done by kernel for the
396 * purposes of getting a NOTE_CHILD notification.
397 */
398 if (kn->kn_flags & EV_FLAG2) {
399 kn->kn_flags &= ~EV_FLAG2;
400 kn->kn_data = kn->kn_sdata; /* ppid */
401 kn->kn_fflags = NOTE_CHILD;
402 kn->kn_sfflags &= ~(NOTE_EXIT | NOTE_EXEC | NOTE_FORK);
403 immediate = true; /* Force immediate activation of child note. */
404 }
405 /*
406 * Internal flag indicating registration done by kernel (for other than
407 * NOTE_CHILD).
408 */
409 if (kn->kn_flags & EV_FLAG1) {
410 kn->kn_flags &= ~EV_FLAG1;
411 }
412
413 knlist_add(p->p_klist, kn, 1);
414
415 /*
416 * Immediately activate any child notes or, in the case of a zombie
417 * target process, exit notes. The latter is necessary to handle the
418 * case where the target process, e.g. a child, dies before the kevent
419 * is registered.
420 */
421 if (immediate || (exiting && filt_proc(kn, NOTE_EXIT)))
422 KNOTE_ACTIVATE(kn, 0);
423
424 PROC_UNLOCK(p);
425
426 return (0);
427 }
428
429 /*
430 * The knote may be attached to a different process, which may exit,
431 * leaving nothing for the knote to be attached to. So when the process
432 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
433 * it will be deleted when read out. However, as part of the knote deletion,
434 * this routine is called, so a check is needed to avoid actually performing
435 * a detach, because the original process does not exist any more.
436 */
437 /* XXX - move to kern_proc.c? */
438 static void
439 filt_procdetach(struct knote *kn)
440 {
441
442 knlist_remove(kn->kn_knlist, kn, 0);
443 kn->kn_ptr.p_proc = NULL;
444 }
445
446 /* XXX - move to kern_proc.c? */
447 static int
448 filt_proc(struct knote *kn, long hint)
449 {
450 struct proc *p;
451 u_int event;
452
453 p = kn->kn_ptr.p_proc;
454 if (p == NULL) /* already activated, from attach filter */
455 return (0);
456
457 /* Mask off extra data. */
458 event = (u_int)hint & NOTE_PCTRLMASK;
459
460 /* If the user is interested in this event, record it. */
461 if (kn->kn_sfflags & event)
462 kn->kn_fflags |= event;
463
464 /* Process is gone, so flag the event as finished. */
465 if (event == NOTE_EXIT) {
466 kn->kn_flags |= EV_EOF | EV_ONESHOT;
467 kn->kn_ptr.p_proc = NULL;
468 if (kn->kn_fflags & NOTE_EXIT)
469 kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig);
470 if (kn->kn_fflags == 0)
471 kn->kn_flags |= EV_DROP;
472 return (1);
473 }
474
475 return (kn->kn_fflags != 0);
476 }
477
478 /*
479 * Called when the process forked. It mostly does the same as the
480 * knote(), activating all knotes registered to be activated when the
481 * process forked. Additionally, for each knote attached to the
482 * parent, check whether user wants to track the new process. If so
483 * attach a new knote to it, and immediately report an event with the
484 * child's pid.
485 */
486 void
487 knote_fork(struct knlist *list, int pid)
488 {
489 struct kqueue *kq;
490 struct knote *kn;
491 struct kevent kev;
492 int error;
493
494 if (list == NULL)
495 return;
496 list->kl_lock(list->kl_lockarg);
497
498 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
499 kq = kn->kn_kq;
500 KQ_LOCK(kq);
501 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) {
502 KQ_UNLOCK(kq);
503 continue;
504 }
505
506 /*
507 * The same as knote(), activate the event.
508 */
509 if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
510 kn->kn_status |= KN_HASKQLOCK;
511 if (kn->kn_fop->f_event(kn, NOTE_FORK))
512 KNOTE_ACTIVATE(kn, 1);
513 kn->kn_status &= ~KN_HASKQLOCK;
514 KQ_UNLOCK(kq);
515 continue;
516 }
517
518 /*
519 * The NOTE_TRACK case. In addition to the activation
520 * of the event, we need to register new events to
521 * track the child. Drop the locks in preparation for
522 * the call to kqueue_register().
523 */
524 kn->kn_status |= KN_INFLUX;
525 KQ_UNLOCK(kq);
526 list->kl_unlock(list->kl_lockarg);
527
528 /*
529 * Activate existing knote and register tracking knotes with
530 * new process.
531 *
532 * First register a knote to get just the child notice. This
533 * must be a separate note from a potential NOTE_EXIT
534 * notification since both NOTE_CHILD and NOTE_EXIT are defined
535 * to use the data field (in conflicting ways).
536 */
537 kev.ident = pid;
538 kev.filter = kn->kn_filter;
539 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT |
540 EV_FLAG2;
541 kev.fflags = kn->kn_sfflags;
542 kev.data = kn->kn_id; /* parent */
543 kev.udata = kn->kn_kevent.udata;/* preserve udata */
544 error = kqueue_register(kq, &kev, NULL, 0);
545 if (error)
546 kn->kn_fflags |= NOTE_TRACKERR;
547
548 /*
549 * Then register another knote to track other potential events
550 * from the new process.
551 */
552 kev.ident = pid;
553 kev.filter = kn->kn_filter;
554 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
555 kev.fflags = kn->kn_sfflags;
556 kev.data = kn->kn_id; /* parent */
557 kev.udata = kn->kn_kevent.udata;/* preserve udata */
558 error = kqueue_register(kq, &kev, NULL, 0);
559 if (error)
560 kn->kn_fflags |= NOTE_TRACKERR;
561 if (kn->kn_fop->f_event(kn, NOTE_FORK))
562 KNOTE_ACTIVATE(kn, 0);
563 KQ_LOCK(kq);
564 kn->kn_status &= ~KN_INFLUX;
565 KQ_UNLOCK_FLUX(kq);
566 list->kl_lock(list->kl_lockarg);
567 }
568 list->kl_unlock(list->kl_lockarg);
569 }
570
571 /*
572 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the
573 * interval timer support code.
574 */
575
576 #define NOTE_TIMER_PRECMASK \
577 (NOTE_SECONDS | NOTE_MSECONDS | NOTE_USECONDS | NOTE_NSECONDS)
578
579 static sbintime_t
580 timer2sbintime(intptr_t data, int flags)
581 {
582 int64_t secs;
583
584 /*
585 * Macros for converting to the fractional second portion of an
586 * sbintime_t using 64bit multiplication to improve precision.
587 */
588 #define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32)
589 #define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32)
590 #define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32)
591 switch (flags & NOTE_TIMER_PRECMASK) {
592 case NOTE_SECONDS:
593 #ifdef __LP64__
594 if (data > (SBT_MAX / SBT_1S))
595 return (SBT_MAX);
596 #endif
597 return ((sbintime_t)data << 32);
598 case NOTE_MSECONDS: /* FALLTHROUGH */
599 case 0:
600 if (data >= 1000) {
601 secs = data / 1000;
602 #ifdef __LP64__
603 if (secs > (SBT_MAX / SBT_1S))
604 return (SBT_MAX);
605 #endif
606 return (secs << 32 | MS_TO_SBT(data % 1000));
607 }
608 return (MS_TO_SBT(data));
609 case NOTE_USECONDS:
610 if (data >= 1000000) {
611 secs = data / 1000000;
612 #ifdef __LP64__
613 if (secs > (SBT_MAX / SBT_1S))
614 return (SBT_MAX);
615 #endif
616 return (secs << 32 | US_TO_SBT(data % 1000000));
617 }
618 return (US_TO_SBT(data));
619 case NOTE_NSECONDS:
620 if (data >= 1000000000) {
621 secs = data / 1000000000;
622 #ifdef __LP64__
623 if (secs > (SBT_MAX / SBT_1S))
624 return (SBT_MAX);
625 #endif
626 return (secs << 32 | US_TO_SBT(data % 1000000000));
627 }
628 return (NS_TO_SBT(data));
629 default:
630 break;
631 }
632 return (-1);
633 }
634
635 struct kq_timer_cb_data {
636 struct callout c;
637 sbintime_t next; /* next timer event fires at */
638 sbintime_t to; /* precalculated timer period */
639 };
640
641 static void
642 filt_timerexpire(void *knx)
643 {
644 struct knote *kn;
645 struct kq_timer_cb_data *kc;
646
647 kn = knx;
648 kn->kn_data++;
649 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
650
651 if ((kn->kn_flags & EV_ONESHOT) != 0)
652 return;
653
654 kc = kn->kn_ptr.p_v;
655 kc->next += kc->to;
656 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn,
657 PCPU_GET(cpuid), C_ABSOLUTE);
658 }
659
660 /*
661 * data contains amount of time to sleep
662 */
663 static int
664 filt_timerattach(struct knote *kn)
665 {
666 struct kq_timer_cb_data *kc;
667 sbintime_t to;
668 unsigned int ncallouts;
669
670 if (kn->kn_sdata < 0)
671 return (EINVAL);
672 if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0)
673 kn->kn_sdata = 1;
674 /* Only precision unit are supported in flags so far */
675 if ((kn->kn_sfflags & ~NOTE_TIMER_PRECMASK) != 0)
676 return (EINVAL);
677
678 to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags);
679 if (to < 0)
680 return (EINVAL);
681
682 do {
683 ncallouts = kq_ncallouts;
684 if (ncallouts >= kq_calloutmax)
685 return (ENOMEM);
686 } while (!atomic_cmpset_int(&kq_ncallouts, ncallouts, ncallouts + 1));
687
688 kn->kn_flags |= EV_CLEAR; /* automatically set */
689 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */
690 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK);
691 callout_init(&kc->c, 1);
692 kc->next = to + sbinuptime();
693 kc->to = to;
694 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn,
695 PCPU_GET(cpuid), C_ABSOLUTE);
696
697 return (0);
698 }
699
700 static void
701 filt_timerdetach(struct knote *kn)
702 {
703 struct kq_timer_cb_data *kc;
704 unsigned int old;
705
706 kc = kn->kn_ptr.p_v;
707 callout_drain(&kc->c);
708 free(kc, M_KQUEUE);
709 old = atomic_fetchadd_int(&kq_ncallouts, -1);
710 KASSERT(old > 0, ("Number of callouts cannot become negative"));
711 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */
712 }
713
714 static int
715 filt_timer(struct knote *kn, long hint)
716 {
717
718 return (kn->kn_data != 0);
719 }
720
721 static int
722 filt_userattach(struct knote *kn)
723 {
724
725 /*
726 * EVFILT_USER knotes are not attached to anything in the kernel.
727 */
728 kn->kn_hook = NULL;
729 if (kn->kn_fflags & NOTE_TRIGGER)
730 kn->kn_hookid = 1;
731 else
732 kn->kn_hookid = 0;
733 return (0);
734 }
735
736 static void
737 filt_userdetach(__unused struct knote *kn)
738 {
739
740 /*
741 * EVFILT_USER knotes are not attached to anything in the kernel.
742 */
743 }
744
745 static int
746 filt_user(struct knote *kn, __unused long hint)
747 {
748
749 return (kn->kn_hookid);
750 }
751
752 static void
753 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
754 {
755 u_int ffctrl;
756
757 switch (type) {
758 case EVENT_REGISTER:
759 if (kev->fflags & NOTE_TRIGGER)
760 kn->kn_hookid = 1;
761
762 ffctrl = kev->fflags & NOTE_FFCTRLMASK;
763 kev->fflags &= NOTE_FFLAGSMASK;
764 switch (ffctrl) {
765 case NOTE_FFNOP:
766 break;
767
768 case NOTE_FFAND:
769 kn->kn_sfflags &= kev->fflags;
770 break;
771
772 case NOTE_FFOR:
773 kn->kn_sfflags |= kev->fflags;
774 break;
775
776 case NOTE_FFCOPY:
777 kn->kn_sfflags = kev->fflags;
778 break;
779
780 default:
781 /* XXX Return error? */
782 break;
783 }
784 kn->kn_sdata = kev->data;
785 if (kev->flags & EV_CLEAR) {
786 kn->kn_hookid = 0;
787 kn->kn_data = 0;
788 kn->kn_fflags = 0;
789 }
790 break;
791
792 case EVENT_PROCESS:
793 *kev = kn->kn_kevent;
794 kev->fflags = kn->kn_sfflags;
795 kev->data = kn->kn_sdata;
796 if (kn->kn_flags & EV_CLEAR) {
797 kn->kn_hookid = 0;
798 kn->kn_data = 0;
799 kn->kn_fflags = 0;
800 }
801 break;
802
803 default:
804 panic("filt_usertouch() - invalid type (%ld)", type);
805 break;
806 }
807 }
808
809 int
810 sys_kqueue(struct thread *td, struct kqueue_args *uap)
811 {
812
813 return (kern_kqueue(td, 0, NULL));
814 }
815
816 static void
817 kqueue_init(struct kqueue *kq)
818 {
819
820 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK);
821 TAILQ_INIT(&kq->kq_head);
822 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
823 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
824 }
825
826 int
827 kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps)
828 {
829 struct filedesc *fdp;
830 struct kqueue *kq;
831 struct file *fp;
832 struct ucred *cred;
833 int fd, error;
834
835 fdp = td->td_proc->p_fd;
836 cred = td->td_ucred;
837 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES)))
838 return (ENOMEM);
839
840 error = falloc_caps(td, &fp, &fd, flags, fcaps);
841 if (error != 0) {
842 chgkqcnt(cred->cr_ruidinfo, -1, 0);
843 return (error);
844 }
845
846 /* An extra reference on `fp' has been held for us by falloc(). */
847 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
848 kqueue_init(kq);
849 kq->kq_fdp = fdp;
850 kq->kq_cred = crhold(cred);
851
852 FILEDESC_XLOCK(fdp);
853 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
854 FILEDESC_XUNLOCK(fdp);
855
856 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
857 fdrop(fp, td);
858
859 td->td_retval[0] = fd;
860 return (0);
861 }
862
863 #ifndef _SYS_SYSPROTO_H_
864 struct kevent_args {
865 int fd;
866 const struct kevent *changelist;
867 int nchanges;
868 struct kevent *eventlist;
869 int nevents;
870 const struct timespec *timeout;
871 };
872 #endif
873 int
874 sys_kevent(struct thread *td, struct kevent_args *uap)
875 {
876 struct timespec ts, *tsp;
877 struct kevent_copyops k_ops = {
878 .arg = uap,
879 .k_copyout = kevent_copyout,
880 .k_copyin = kevent_copyin,
881 };
882 #ifdef KTRACE
883 struct kevent *eventlist = uap->eventlist;
884 #endif
885 int error;
886
887 if (uap->timeout != NULL) {
888 error = copyin(uap->timeout, &ts, sizeof(ts));
889 if (error)
890 return (error);
891 tsp = &ts;
892 } else
893 tsp = NULL;
894
895 #ifdef KTRACE
896 if (KTRPOINT(td, KTR_STRUCT_ARRAY))
897 ktrstructarray("kevent", UIO_USERSPACE, uap->changelist,
898 uap->nchanges, sizeof(struct kevent));
899 #endif
900
901 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
902 &k_ops, tsp);
903
904 #ifdef KTRACE
905 if (error == 0 && KTRPOINT(td, KTR_STRUCT_ARRAY))
906 ktrstructarray("kevent", UIO_USERSPACE, eventlist,
907 td->td_retval[0], sizeof(struct kevent));
908 #endif
909
910 return (error);
911 }
912
913 /*
914 * Copy 'count' items into the destination list pointed to by uap->eventlist.
915 */
916 static int
917 kevent_copyout(void *arg, struct kevent *kevp, int count)
918 {
919 struct kevent_args *uap;
920 int error;
921
922 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
923 uap = (struct kevent_args *)arg;
924
925 error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
926 if (error == 0)
927 uap->eventlist += count;
928 return (error);
929 }
930
931 /*
932 * Copy 'count' items from the list pointed to by uap->changelist.
933 */
934 static int
935 kevent_copyin(void *arg, struct kevent *kevp, int count)
936 {
937 struct kevent_args *uap;
938 int error;
939
940 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
941 uap = (struct kevent_args *)arg;
942
943 error = copyin(uap->changelist, kevp, count * sizeof *kevp);
944 if (error == 0)
945 uap->changelist += count;
946 return (error);
947 }
948
949 int
950 kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
951 struct kevent_copyops *k_ops, const struct timespec *timeout)
952 {
953 cap_rights_t rights;
954 struct file *fp;
955 int error;
956
957 cap_rights_init(&rights);
958 if (nchanges > 0)
959 cap_rights_set(&rights, CAP_KQUEUE_CHANGE);
960 if (nevents > 0)
961 cap_rights_set(&rights, CAP_KQUEUE_EVENT);
962 error = fget(td, fd, &rights, &fp);
963 if (error != 0)
964 return (error);
965
966 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout);
967 fdrop(fp, td);
968
969 return (error);
970 }
971
972 static int
973 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents,
974 struct kevent_copyops *k_ops, const struct timespec *timeout)
975 {
976 struct kevent keva[KQ_NEVENTS];
977 struct kevent *kevp, *changes;
978 int i, n, nerrors, error;
979
980 nerrors = 0;
981 while (nchanges > 0) {
982 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
983 error = k_ops->k_copyin(k_ops->arg, keva, n);
984 if (error)
985 return (error);
986 changes = keva;
987 for (i = 0; i < n; i++) {
988 kevp = &changes[i];
989 if (!kevp->filter)
990 continue;
991 kevp->flags &= ~EV_SYSFLAGS;
992 error = kqueue_register(kq, kevp, td, 1);
993 if (error || (kevp->flags & EV_RECEIPT)) {
994 if (nevents == 0)
995 return (error);
996 kevp->flags = EV_ERROR;
997 kevp->data = error;
998 (void)k_ops->k_copyout(k_ops->arg, kevp, 1);
999 nevents--;
1000 nerrors++;
1001 }
1002 }
1003 nchanges -= n;
1004 }
1005 if (nerrors) {
1006 td->td_retval[0] = nerrors;
1007 return (0);
1008 }
1009
1010 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td));
1011 }
1012
1013 int
1014 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents,
1015 struct kevent_copyops *k_ops, const struct timespec *timeout)
1016 {
1017 struct kqueue *kq;
1018 int error;
1019
1020 error = kqueue_acquire(fp, &kq);
1021 if (error != 0)
1022 return (error);
1023 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout);
1024 kqueue_release(kq, 0);
1025 return (error);
1026 }
1027
1028 /*
1029 * Performs a kevent() call on a temporarily created kqueue. This can be
1030 * used to perform one-shot polling, similar to poll() and select().
1031 */
1032 int
1033 kern_kevent_anonymous(struct thread *td, int nevents,
1034 struct kevent_copyops *k_ops)
1035 {
1036 struct kqueue kq = {};
1037 int error;
1038
1039 kqueue_init(&kq);
1040 kq.kq_refcnt = 1;
1041 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL);
1042 kqueue_drain(&kq, td);
1043 kqueue_destroy(&kq);
1044 return (error);
1045 }
1046
1047 int
1048 kqueue_add_filteropts(int filt, struct filterops *filtops)
1049 {
1050 int error;
1051
1052 error = 0;
1053 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
1054 printf(
1055 "trying to add a filterop that is out of range: %d is beyond %d\n",
1056 ~filt, EVFILT_SYSCOUNT);
1057 return EINVAL;
1058 }
1059 mtx_lock(&filterops_lock);
1060 if (sysfilt_ops[~filt].for_fop != &null_filtops &&
1061 sysfilt_ops[~filt].for_fop != NULL)
1062 error = EEXIST;
1063 else {
1064 sysfilt_ops[~filt].for_fop = filtops;
1065 sysfilt_ops[~filt].for_refcnt = 0;
1066 }
1067 mtx_unlock(&filterops_lock);
1068
1069 return (error);
1070 }
1071
1072 int
1073 kqueue_del_filteropts(int filt)
1074 {
1075 int error;
1076
1077 error = 0;
1078 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1079 return EINVAL;
1080
1081 mtx_lock(&filterops_lock);
1082 if (sysfilt_ops[~filt].for_fop == &null_filtops ||
1083 sysfilt_ops[~filt].for_fop == NULL)
1084 error = EINVAL;
1085 else if (sysfilt_ops[~filt].for_refcnt != 0)
1086 error = EBUSY;
1087 else {
1088 sysfilt_ops[~filt].for_fop = &null_filtops;
1089 sysfilt_ops[~filt].for_refcnt = 0;
1090 }
1091 mtx_unlock(&filterops_lock);
1092
1093 return error;
1094 }
1095
1096 static struct filterops *
1097 kqueue_fo_find(int filt)
1098 {
1099
1100 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1101 return NULL;
1102
1103 if (sysfilt_ops[~filt].for_nolock)
1104 return sysfilt_ops[~filt].for_fop;
1105
1106 mtx_lock(&filterops_lock);
1107 sysfilt_ops[~filt].for_refcnt++;
1108 if (sysfilt_ops[~filt].for_fop == NULL)
1109 sysfilt_ops[~filt].for_fop = &null_filtops;
1110 mtx_unlock(&filterops_lock);
1111
1112 return sysfilt_ops[~filt].for_fop;
1113 }
1114
1115 static void
1116 kqueue_fo_release(int filt)
1117 {
1118
1119 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1120 return;
1121
1122 if (sysfilt_ops[~filt].for_nolock)
1123 return;
1124
1125 mtx_lock(&filterops_lock);
1126 KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
1127 ("filter object refcount not valid on release"));
1128 sysfilt_ops[~filt].for_refcnt--;
1129 mtx_unlock(&filterops_lock);
1130 }
1131
1132 /*
1133 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will
1134 * influence if memory allocation should wait. Make sure it is 0 if you
1135 * hold any mutexes.
1136 */
1137 static int
1138 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok)
1139 {
1140 struct filterops *fops;
1141 struct file *fp;
1142 struct knote *kn, *tkn;
1143 struct knlist *knl;
1144 cap_rights_t rights;
1145 int error, filt, event;
1146 int haskqglobal, filedesc_unlock;
1147
1148 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE))
1149 return (EINVAL);
1150
1151 fp = NULL;
1152 kn = NULL;
1153 knl = NULL;
1154 error = 0;
1155 haskqglobal = 0;
1156 filedesc_unlock = 0;
1157
1158 filt = kev->filter;
1159 fops = kqueue_fo_find(filt);
1160 if (fops == NULL)
1161 return EINVAL;
1162
1163 if (kev->flags & EV_ADD) {
1164 /*
1165 * Prevent waiting with locks. Non-sleepable
1166 * allocation failures are handled in the loop, only
1167 * if the spare knote appears to be actually required.
1168 */
1169 tkn = knote_alloc(waitok);
1170 } else {
1171 tkn = NULL;
1172 }
1173
1174 findkn:
1175 if (fops->f_isfd) {
1176 KASSERT(td != NULL, ("td is NULL"));
1177 if (kev->ident > INT_MAX)
1178 error = EBADF;
1179 else
1180 error = fget(td, kev->ident,
1181 cap_rights_init(&rights, CAP_EVENT), &fp);
1182 if (error)
1183 goto done;
1184
1185 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
1186 kev->ident, 0) != 0) {
1187 /* try again */
1188 fdrop(fp, td);
1189 fp = NULL;
1190 error = kqueue_expand(kq, fops, kev->ident, waitok);
1191 if (error)
1192 goto done;
1193 goto findkn;
1194 }
1195
1196 if (fp->f_type == DTYPE_KQUEUE) {
1197 /*
1198 * If we add some intelligence about what we are doing,
1199 * we should be able to support events on ourselves.
1200 * We need to know when we are doing this to prevent
1201 * getting both the knlist lock and the kq lock since
1202 * they are the same thing.
1203 */
1204 if (fp->f_data == kq) {
1205 error = EINVAL;
1206 goto done;
1207 }
1208
1209 /*
1210 * Pre-lock the filedesc before the global
1211 * lock mutex, see the comment in
1212 * kqueue_close().
1213 */
1214 FILEDESC_XLOCK(td->td_proc->p_fd);
1215 filedesc_unlock = 1;
1216 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1217 }
1218
1219 KQ_LOCK(kq);
1220 if (kev->ident < kq->kq_knlistsize) {
1221 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
1222 if (kev->filter == kn->kn_filter)
1223 break;
1224 }
1225 } else {
1226 if ((kev->flags & EV_ADD) == EV_ADD)
1227 kqueue_expand(kq, fops, kev->ident, waitok);
1228
1229 KQ_LOCK(kq);
1230
1231 /*
1232 * If possible, find an existing knote to use for this kevent.
1233 */
1234 if (kev->filter == EVFILT_PROC &&
1235 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) {
1236 /* This is an internal creation of a process tracking
1237 * note. Don't attempt to coalesce this with an
1238 * existing note.
1239 */
1240 ;
1241 } else if (kq->kq_knhashmask != 0) {
1242 struct klist *list;
1243
1244 list = &kq->kq_knhash[
1245 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
1246 SLIST_FOREACH(kn, list, kn_link)
1247 if (kev->ident == kn->kn_id &&
1248 kev->filter == kn->kn_filter)
1249 break;
1250 }
1251 }
1252
1253 /* knote is in the process of changing, wait for it to stabilize. */
1254 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1255 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1256 if (filedesc_unlock) {
1257 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1258 filedesc_unlock = 0;
1259 }
1260 kq->kq_state |= KQ_FLUXWAIT;
1261 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
1262 if (fp != NULL) {
1263 fdrop(fp, td);
1264 fp = NULL;
1265 }
1266 goto findkn;
1267 }
1268
1269 /*
1270 * kn now contains the matching knote, or NULL if no match
1271 */
1272 if (kn == NULL) {
1273 if (kev->flags & EV_ADD) {
1274 kn = tkn;
1275 tkn = NULL;
1276 if (kn == NULL) {
1277 KQ_UNLOCK(kq);
1278 error = ENOMEM;
1279 goto done;
1280 }
1281 kn->kn_fp = fp;
1282 kn->kn_kq = kq;
1283 kn->kn_fop = fops;
1284 /*
1285 * apply reference counts to knote structure, and
1286 * do not release it at the end of this routine.
1287 */
1288 fops = NULL;
1289 fp = NULL;
1290
1291 kn->kn_sfflags = kev->fflags;
1292 kn->kn_sdata = kev->data;
1293 kev->fflags = 0;
1294 kev->data = 0;
1295 kn->kn_kevent = *kev;
1296 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
1297 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT);
1298 kn->kn_status = KN_INFLUX|KN_DETACHED;
1299 if ((kev->flags & EV_DISABLE) != 0)
1300 kn->kn_status |= KN_DISABLED;
1301
1302 error = knote_attach(kn, kq);
1303 KQ_UNLOCK(kq);
1304 if (error != 0) {
1305 tkn = kn;
1306 goto done;
1307 }
1308
1309 if ((error = kn->kn_fop->f_attach(kn)) != 0) {
1310 knote_drop(kn, td);
1311 goto done;
1312 }
1313 knl = kn_list_lock(kn);
1314 goto done_ev_add;
1315 } else {
1316 /* No matching knote and the EV_ADD flag is not set. */
1317 KQ_UNLOCK(kq);
1318 error = ENOENT;
1319 goto done;
1320 }
1321 }
1322
1323 if (kev->flags & EV_DELETE) {
1324 kn->kn_status |= KN_INFLUX;
1325 KQ_UNLOCK(kq);
1326 if (!(kn->kn_status & KN_DETACHED))
1327 kn->kn_fop->f_detach(kn);
1328 knote_drop(kn, td);
1329 goto done;
1330 }
1331
1332 if (kev->flags & EV_FORCEONESHOT) {
1333 kn->kn_flags |= EV_ONESHOT;
1334 KNOTE_ACTIVATE(kn, 1);
1335 }
1336
1337 if ((kev->flags & EV_ENABLE) != 0)
1338 kn->kn_status &= ~KN_DISABLED;
1339 else if ((kev->flags & EV_DISABLE) != 0)
1340 kn->kn_status |= KN_DISABLED;
1341
1342 /*
1343 * The user may change some filter values after the initial EV_ADD,
1344 * but doing so will not reset any filter which has already been
1345 * triggered.
1346 */
1347 kn->kn_status |= KN_INFLUX | KN_SCAN;
1348 KQ_UNLOCK(kq);
1349 knl = kn_list_lock(kn);
1350 kn->kn_kevent.udata = kev->udata;
1351 if (!fops->f_isfd && fops->f_touch != NULL) {
1352 fops->f_touch(kn, kev, EVENT_REGISTER);
1353 } else {
1354 kn->kn_sfflags = kev->fflags;
1355 kn->kn_sdata = kev->data;
1356 }
1357
1358 done_ev_add:
1359 /*
1360 * We can get here with kn->kn_knlist == NULL. This can happen when
1361 * the initial attach event decides that the event is "completed"
1362 * already, e.g., filt_procattach() is called on a zombie process. It
1363 * will call filt_proc() which will remove it from the list, and NULL
1364 * kn_knlist.
1365 *
1366 * KN_DISABLED will be stable while the knote is in flux, so the
1367 * unlocked read will not race with an update.
1368 */
1369 if ((kn->kn_status & KN_DISABLED) == 0)
1370 event = kn->kn_fop->f_event(kn, 0);
1371 else
1372 event = 0;
1373
1374 KQ_LOCK(kq);
1375 if (event)
1376 kn->kn_status |= KN_ACTIVE;
1377 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) ==
1378 KN_ACTIVE)
1379 knote_enqueue(kn);
1380 kn->kn_status &= ~(KN_INFLUX | KN_SCAN);
1381 kn_list_unlock(knl);
1382 KQ_UNLOCK_FLUX(kq);
1383
1384 done:
1385 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1386 if (filedesc_unlock)
1387 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1388 if (fp != NULL)
1389 fdrop(fp, td);
1390 knote_free(tkn);
1391 if (fops != NULL)
1392 kqueue_fo_release(filt);
1393 return (error);
1394 }
1395
1396 static int
1397 kqueue_acquire(struct file *fp, struct kqueue **kqp)
1398 {
1399 int error;
1400 struct kqueue *kq;
1401
1402 error = 0;
1403
1404 kq = fp->f_data;
1405 if (fp->f_type != DTYPE_KQUEUE || kq == NULL)
1406 return (EBADF);
1407 *kqp = kq;
1408 KQ_LOCK(kq);
1409 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
1410 KQ_UNLOCK(kq);
1411 return (EBADF);
1412 }
1413 kq->kq_refcnt++;
1414 KQ_UNLOCK(kq);
1415
1416 return error;
1417 }
1418
1419 static void
1420 kqueue_release(struct kqueue *kq, int locked)
1421 {
1422 if (locked)
1423 KQ_OWNED(kq);
1424 else
1425 KQ_LOCK(kq);
1426 kq->kq_refcnt--;
1427 if (kq->kq_refcnt == 1)
1428 wakeup(&kq->kq_refcnt);
1429 if (!locked)
1430 KQ_UNLOCK(kq);
1431 }
1432
1433 static void
1434 kqueue_schedtask(struct kqueue *kq)
1435 {
1436
1437 KQ_OWNED(kq);
1438 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
1439 ("scheduling kqueue task while draining"));
1440
1441 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
1442 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task);
1443 kq->kq_state |= KQ_TASKSCHED;
1444 }
1445 }
1446
1447 /*
1448 * Expand the kq to make sure we have storage for fops/ident pair.
1449 *
1450 * Return 0 on success (or no work necessary), return errno on failure.
1451 *
1452 * Not calling hashinit w/ waitok (proper malloc flag) should be safe.
1453 * If kqueue_register is called from a non-fd context, there usually/should
1454 * be no locks held.
1455 */
1456 static int
1457 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident,
1458 int waitok)
1459 {
1460 struct klist *list, *tmp_knhash, *to_free;
1461 u_long tmp_knhashmask;
1462 int size;
1463 int fd;
1464 int mflag = waitok ? M_WAITOK : M_NOWAIT;
1465
1466 KQ_NOTOWNED(kq);
1467
1468 to_free = NULL;
1469 if (fops->f_isfd) {
1470 fd = ident;
1471 if (kq->kq_knlistsize <= fd) {
1472 size = kq->kq_knlistsize;
1473 while (size <= fd)
1474 size += KQEXTENT;
1475 list = malloc(size * sizeof(*list), M_KQUEUE, mflag);
1476 if (list == NULL)
1477 return ENOMEM;
1478 KQ_LOCK(kq);
1479 if (kq->kq_knlistsize > fd) {
1480 to_free = list;
1481 list = NULL;
1482 } else {
1483 if (kq->kq_knlist != NULL) {
1484 bcopy(kq->kq_knlist, list,
1485 kq->kq_knlistsize * sizeof(*list));
1486 to_free = kq->kq_knlist;
1487 kq->kq_knlist = NULL;
1488 }
1489 bzero((caddr_t)list +
1490 kq->kq_knlistsize * sizeof(*list),
1491 (size - kq->kq_knlistsize) * sizeof(*list));
1492 kq->kq_knlistsize = size;
1493 kq->kq_knlist = list;
1494 }
1495 KQ_UNLOCK(kq);
1496 }
1497 } else {
1498 if (kq->kq_knhashmask == 0) {
1499 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
1500 &tmp_knhashmask);
1501 if (tmp_knhash == NULL)
1502 return ENOMEM;
1503 KQ_LOCK(kq);
1504 if (kq->kq_knhashmask == 0) {
1505 kq->kq_knhash = tmp_knhash;
1506 kq->kq_knhashmask = tmp_knhashmask;
1507 } else {
1508 to_free = tmp_knhash;
1509 }
1510 KQ_UNLOCK(kq);
1511 }
1512 }
1513 free(to_free, M_KQUEUE);
1514
1515 KQ_NOTOWNED(kq);
1516 return 0;
1517 }
1518
1519 static void
1520 kqueue_task(void *arg, int pending)
1521 {
1522 struct kqueue *kq;
1523 int haskqglobal;
1524
1525 haskqglobal = 0;
1526 kq = arg;
1527
1528 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1529 KQ_LOCK(kq);
1530
1531 KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
1532
1533 kq->kq_state &= ~KQ_TASKSCHED;
1534 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
1535 wakeup(&kq->kq_state);
1536 }
1537 KQ_UNLOCK(kq);
1538 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1539 }
1540
1541 /*
1542 * Scan, update kn_data (if not ONESHOT), and copyout triggered events.
1543 * We treat KN_MARKER knotes as if they are INFLUX.
1544 */
1545 static int
1546 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
1547 const struct timespec *tsp, struct kevent *keva, struct thread *td)
1548 {
1549 struct kevent *kevp;
1550 struct knote *kn, *marker;
1551 struct knlist *knl;
1552 sbintime_t asbt, rsbt;
1553 int count, error, haskqglobal, influx, nkev, touch;
1554
1555 count = maxevents;
1556 nkev = 0;
1557 error = 0;
1558 haskqglobal = 0;
1559
1560 if (maxevents == 0)
1561 goto done_nl;
1562
1563 rsbt = 0;
1564 if (tsp != NULL) {
1565 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 ||
1566 tsp->tv_nsec >= 1000000000) {
1567 error = EINVAL;
1568 goto done_nl;
1569 }
1570 if (timespecisset(tsp)) {
1571 if (tsp->tv_sec <= INT32_MAX) {
1572 rsbt = tstosbt(*tsp);
1573 if (TIMESEL(&asbt, rsbt))
1574 asbt += tc_tick_sbt;
1575 if (asbt <= SBT_MAX - rsbt)
1576 asbt += rsbt;
1577 else
1578 asbt = 0;
1579 rsbt >>= tc_precexp;
1580 } else
1581 asbt = 0;
1582 } else
1583 asbt = -1;
1584 } else
1585 asbt = 0;
1586 marker = knote_alloc(1);
1587 marker->kn_status = KN_MARKER;
1588 KQ_LOCK(kq);
1589
1590 retry:
1591 kevp = keva;
1592 if (kq->kq_count == 0) {
1593 if (asbt == -1) {
1594 error = EWOULDBLOCK;
1595 } else {
1596 kq->kq_state |= KQ_SLEEP;
1597 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH,
1598 "kqread", asbt, rsbt, C_ABSOLUTE);
1599 }
1600 if (error == 0)
1601 goto retry;
1602 /* don't restart after signals... */
1603 if (error == ERESTART)
1604 error = EINTR;
1605 else if (error == EWOULDBLOCK)
1606 error = 0;
1607 goto done;
1608 }
1609
1610 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
1611 influx = 0;
1612 while (count) {
1613 KQ_OWNED(kq);
1614 kn = TAILQ_FIRST(&kq->kq_head);
1615
1616 if ((kn->kn_status == KN_MARKER && kn != marker) ||
1617 (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1618 if (influx) {
1619 influx = 0;
1620 KQ_FLUX_WAKEUP(kq);
1621 }
1622 kq->kq_state |= KQ_FLUXWAIT;
1623 error = msleep(kq, &kq->kq_lock, PSOCK,
1624 "kqflxwt", 0);
1625 continue;
1626 }
1627
1628 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
1629 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
1630 kn->kn_status &= ~KN_QUEUED;
1631 kq->kq_count--;
1632 continue;
1633 }
1634 if (kn == marker) {
1635 KQ_FLUX_WAKEUP(kq);
1636 if (count == maxevents)
1637 goto retry;
1638 goto done;
1639 }
1640 KASSERT((kn->kn_status & KN_INFLUX) == 0,
1641 ("KN_INFLUX set when not suppose to be"));
1642
1643 if ((kn->kn_flags & EV_DROP) == EV_DROP) {
1644 kn->kn_status &= ~KN_QUEUED;
1645 kn->kn_status |= KN_INFLUX;
1646 kq->kq_count--;
1647 KQ_UNLOCK(kq);
1648 /*
1649 * We don't need to lock the list since we've marked
1650 * it _INFLUX.
1651 */
1652 if (!(kn->kn_status & KN_DETACHED))
1653 kn->kn_fop->f_detach(kn);
1654 knote_drop(kn, td);
1655 KQ_LOCK(kq);
1656 continue;
1657 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
1658 kn->kn_status &= ~KN_QUEUED;
1659 kn->kn_status |= KN_INFLUX;
1660 kq->kq_count--;
1661 KQ_UNLOCK(kq);
1662 /*
1663 * We don't need to lock the list since we've marked
1664 * it _INFLUX.
1665 */
1666 *kevp = kn->kn_kevent;
1667 if (!(kn->kn_status & KN_DETACHED))
1668 kn->kn_fop->f_detach(kn);
1669 knote_drop(kn, td);
1670 KQ_LOCK(kq);
1671 kn = NULL;
1672 } else {
1673 kn->kn_status |= KN_INFLUX | KN_SCAN;
1674 KQ_UNLOCK(kq);
1675 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
1676 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1677 knl = kn_list_lock(kn);
1678 if (kn->kn_fop->f_event(kn, 0) == 0) {
1679 KQ_LOCK(kq);
1680 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1681 kn->kn_status &=
1682 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX |
1683 KN_SCAN);
1684 kq->kq_count--;
1685 kn_list_unlock(knl);
1686 influx = 1;
1687 continue;
1688 }
1689 touch = (!kn->kn_fop->f_isfd &&
1690 kn->kn_fop->f_touch != NULL);
1691 if (touch)
1692 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS);
1693 else
1694 *kevp = kn->kn_kevent;
1695 KQ_LOCK(kq);
1696 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1697 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
1698 /*
1699 * Manually clear knotes who weren't
1700 * 'touch'ed.
1701 */
1702 if (touch == 0 && kn->kn_flags & EV_CLEAR) {
1703 kn->kn_data = 0;
1704 kn->kn_fflags = 0;
1705 }
1706 if (kn->kn_flags & EV_DISPATCH)
1707 kn->kn_status |= KN_DISABLED;
1708 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
1709 kq->kq_count--;
1710 } else
1711 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
1712
1713 kn->kn_status &= ~(KN_INFLUX | KN_SCAN);
1714 kn_list_unlock(knl);
1715 influx = 1;
1716 }
1717
1718 /* we are returning a copy to the user */
1719 kevp++;
1720 nkev++;
1721 count--;
1722
1723 if (nkev == KQ_NEVENTS) {
1724 influx = 0;
1725 KQ_UNLOCK_FLUX(kq);
1726 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1727 nkev = 0;
1728 kevp = keva;
1729 KQ_LOCK(kq);
1730 if (error)
1731 break;
1732 }
1733 }
1734 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
1735 done:
1736 KQ_OWNED(kq);
1737 KQ_UNLOCK_FLUX(kq);
1738 knote_free(marker);
1739 done_nl:
1740 KQ_NOTOWNED(kq);
1741 if (nkev != 0)
1742 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1743 td->td_retval[0] = maxevents - count;
1744 return (error);
1745 }
1746
1747 /*ARGSUSED*/
1748 static int
1749 kqueue_ioctl(struct file *fp, u_long cmd, void *data,
1750 struct ucred *active_cred, struct thread *td)
1751 {
1752 /*
1753 * Enabling sigio causes two major problems:
1754 * 1) infinite recursion:
1755 * Synopsys: kevent is being used to track signals and have FIOASYNC
1756 * set. On receipt of a signal this will cause a kqueue to recurse
1757 * into itself over and over. Sending the sigio causes the kqueue
1758 * to become ready, which in turn posts sigio again, forever.
1759 * Solution: this can be solved by setting a flag in the kqueue that
1760 * we have a SIGIO in progress.
1761 * 2) locking problems:
1762 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
1763 * us above the proc and pgrp locks.
1764 * Solution: Post a signal using an async mechanism, being sure to
1765 * record a generation count in the delivery so that we do not deliver
1766 * a signal to the wrong process.
1767 *
1768 * Note, these two mechanisms are somewhat mutually exclusive!
1769 */
1770 #if 0
1771 struct kqueue *kq;
1772
1773 kq = fp->f_data;
1774 switch (cmd) {
1775 case FIOASYNC:
1776 if (*(int *)data) {
1777 kq->kq_state |= KQ_ASYNC;
1778 } else {
1779 kq->kq_state &= ~KQ_ASYNC;
1780 }
1781 return (0);
1782
1783 case FIOSETOWN:
1784 return (fsetown(*(int *)data, &kq->kq_sigio));
1785
1786 case FIOGETOWN:
1787 *(int *)data = fgetown(&kq->kq_sigio);
1788 return (0);
1789 }
1790 #endif
1791
1792 return (ENOTTY);
1793 }
1794
1795 /*ARGSUSED*/
1796 static int
1797 kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
1798 struct thread *td)
1799 {
1800 struct kqueue *kq;
1801 int revents = 0;
1802 int error;
1803
1804 if ((error = kqueue_acquire(fp, &kq)))
1805 return POLLERR;
1806
1807 KQ_LOCK(kq);
1808 if (events & (POLLIN | POLLRDNORM)) {
1809 if (kq->kq_count) {
1810 revents |= events & (POLLIN | POLLRDNORM);
1811 } else {
1812 selrecord(td, &kq->kq_sel);
1813 if (SEL_WAITING(&kq->kq_sel))
1814 kq->kq_state |= KQ_SEL;
1815 }
1816 }
1817 kqueue_release(kq, 1);
1818 KQ_UNLOCK(kq);
1819 return (revents);
1820 }
1821
1822 /*ARGSUSED*/
1823 static int
1824 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
1825 struct thread *td)
1826 {
1827
1828 bzero((void *)st, sizeof *st);
1829 /*
1830 * We no longer return kq_count because the unlocked value is useless.
1831 * If you spent all this time getting the count, why not spend your
1832 * syscall better by calling kevent?
1833 *
1834 * XXX - This is needed for libc_r.
1835 */
1836 st->st_mode = S_IFIFO;
1837 return (0);
1838 }
1839
1840 static void
1841 kqueue_drain(struct kqueue *kq, struct thread *td)
1842 {
1843 struct knote *kn;
1844 int i;
1845
1846 KQ_LOCK(kq);
1847
1848 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
1849 ("kqueue already closing"));
1850 kq->kq_state |= KQ_CLOSING;
1851 if (kq->kq_refcnt > 1)
1852 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
1853
1854 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
1855
1856 KASSERT(knlist_empty(&kq->kq_sel.si_note),
1857 ("kqueue's knlist not empty"));
1858
1859 for (i = 0; i < kq->kq_knlistsize; i++) {
1860 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
1861 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1862 kq->kq_state |= KQ_FLUXWAIT;
1863 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
1864 continue;
1865 }
1866 kn->kn_status |= KN_INFLUX;
1867 KQ_UNLOCK(kq);
1868 if (!(kn->kn_status & KN_DETACHED))
1869 kn->kn_fop->f_detach(kn);
1870 knote_drop(kn, td);
1871 KQ_LOCK(kq);
1872 }
1873 }
1874 if (kq->kq_knhashmask != 0) {
1875 for (i = 0; i <= kq->kq_knhashmask; i++) {
1876 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
1877 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1878 kq->kq_state |= KQ_FLUXWAIT;
1879 msleep(kq, &kq->kq_lock, PSOCK,
1880 "kqclo2", 0);
1881 continue;
1882 }
1883 kn->kn_status |= KN_INFLUX;
1884 KQ_UNLOCK(kq);
1885 if (!(kn->kn_status & KN_DETACHED))
1886 kn->kn_fop->f_detach(kn);
1887 knote_drop(kn, td);
1888 KQ_LOCK(kq);
1889 }
1890 }
1891 }
1892
1893 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
1894 kq->kq_state |= KQ_TASKDRAIN;
1895 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
1896 }
1897
1898 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
1899 selwakeuppri(&kq->kq_sel, PSOCK);
1900 if (!SEL_WAITING(&kq->kq_sel))
1901 kq->kq_state &= ~KQ_SEL;
1902 }
1903
1904 KQ_UNLOCK(kq);
1905 }
1906
1907 static void
1908 kqueue_destroy(struct kqueue *kq)
1909 {
1910
1911 KASSERT(kq->kq_fdp == NULL,
1912 ("kqueue still attached to a file descriptor"));
1913 seldrain(&kq->kq_sel);
1914 knlist_destroy(&kq->kq_sel.si_note);
1915 mtx_destroy(&kq->kq_lock);
1916
1917 if (kq->kq_knhash != NULL)
1918 free(kq->kq_knhash, M_KQUEUE);
1919 if (kq->kq_knlist != NULL)
1920 free(kq->kq_knlist, M_KQUEUE);
1921
1922 funsetown(&kq->kq_sigio);
1923 }
1924
1925 /*ARGSUSED*/
1926 static int
1927 kqueue_close(struct file *fp, struct thread *td)
1928 {
1929 struct kqueue *kq = fp->f_data;
1930 struct filedesc *fdp;
1931 int error;
1932 int filedesc_unlock;
1933
1934 if ((error = kqueue_acquire(fp, &kq)))
1935 return error;
1936 kqueue_drain(kq, td);
1937
1938 /*
1939 * We could be called due to the knote_drop() doing fdrop(),
1940 * called from kqueue_register(). In this case the global
1941 * lock is owned, and filedesc sx is locked before, to not
1942 * take the sleepable lock after non-sleepable.
1943 */
1944 fdp = kq->kq_fdp;
1945 kq->kq_fdp = NULL;
1946 if (!sx_xlocked(FILEDESC_LOCK(fdp))) {
1947 FILEDESC_XLOCK(fdp);
1948 filedesc_unlock = 1;
1949 } else
1950 filedesc_unlock = 0;
1951 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list);
1952 if (filedesc_unlock)
1953 FILEDESC_XUNLOCK(fdp);
1954
1955 kqueue_destroy(kq);
1956 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0);
1957 crfree(kq->kq_cred);
1958 free(kq, M_KQUEUE);
1959 fp->f_data = NULL;
1960
1961 return (0);
1962 }
1963
1964 static int
1965 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
1966 {
1967
1968 kif->kf_type = KF_TYPE_KQUEUE;
1969 return (0);
1970 }
1971
1972 static void
1973 kqueue_wakeup(struct kqueue *kq)
1974 {
1975 KQ_OWNED(kq);
1976
1977 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
1978 kq->kq_state &= ~KQ_SLEEP;
1979 wakeup(kq);
1980 }
1981 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
1982 selwakeuppri(&kq->kq_sel, PSOCK);
1983 if (!SEL_WAITING(&kq->kq_sel))
1984 kq->kq_state &= ~KQ_SEL;
1985 }
1986 if (!knlist_empty(&kq->kq_sel.si_note))
1987 kqueue_schedtask(kq);
1988 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
1989 pgsigio(&kq->kq_sigio, SIGIO, 0);
1990 }
1991 }
1992
1993 /*
1994 * Walk down a list of knotes, activating them if their event has triggered.
1995 *
1996 * There is a possibility to optimize in the case of one kq watching another.
1997 * Instead of scheduling a task to wake it up, you could pass enough state
1998 * down the chain to make up the parent kqueue. Make this code functional
1999 * first.
2000 */
2001 void
2002 knote(struct knlist *list, long hint, int lockflags)
2003 {
2004 struct kqueue *kq;
2005 struct knote *kn, *tkn;
2006 int error;
2007 bool own_influx;
2008
2009 if (list == NULL)
2010 return;
2011
2012 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
2013
2014 if ((lockflags & KNF_LISTLOCKED) == 0)
2015 list->kl_lock(list->kl_lockarg);
2016
2017 /*
2018 * If we unlock the list lock (and set KN_INFLUX), we can
2019 * eliminate the kqueue scheduling, but this will introduce
2020 * four lock/unlock's for each knote to test. Also, marker
2021 * would be needed to keep iteration position, since filters
2022 * or other threads could remove events.
2023 */
2024 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) {
2025 kq = kn->kn_kq;
2026 KQ_LOCK(kq);
2027 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) {
2028 /*
2029 * Do not process the influx notes, except for
2030 * the influx coming from the kq unlock in the
2031 * kqueue_scan(). In the later case, we do
2032 * not interfere with the scan, since the code
2033 * fragment in kqueue_scan() locks the knlist,
2034 * and cannot proceed until we finished.
2035 */
2036 KQ_UNLOCK(kq);
2037 } else if ((lockflags & KNF_NOKQLOCK) != 0) {
2038 own_influx = (kn->kn_status & KN_INFLUX) == 0;
2039 if (own_influx)
2040 kn->kn_status |= KN_INFLUX;
2041 KQ_UNLOCK(kq);
2042 error = kn->kn_fop->f_event(kn, hint);
2043 KQ_LOCK(kq);
2044 if (own_influx)
2045 kn->kn_status &= ~KN_INFLUX;
2046 if (error)
2047 KNOTE_ACTIVATE(kn, 1);
2048 KQ_UNLOCK_FLUX(kq);
2049 } else {
2050 kn->kn_status |= KN_HASKQLOCK;
2051 if (kn->kn_fop->f_event(kn, hint))
2052 KNOTE_ACTIVATE(kn, 1);
2053 kn->kn_status &= ~KN_HASKQLOCK;
2054 KQ_UNLOCK(kq);
2055 }
2056 }
2057 if ((lockflags & KNF_LISTLOCKED) == 0)
2058 list->kl_unlock(list->kl_lockarg);
2059 }
2060
2061 /*
2062 * add a knote to a knlist
2063 */
2064 void
2065 knlist_add(struct knlist *knl, struct knote *kn, int islocked)
2066 {
2067 KNL_ASSERT_LOCK(knl, islocked);
2068 KQ_NOTOWNED(kn->kn_kq);
2069 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) ==
2070 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED"));
2071 if (!islocked)
2072 knl->kl_lock(knl->kl_lockarg);
2073 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext);
2074 if (!islocked)
2075 knl->kl_unlock(knl->kl_lockarg);
2076 KQ_LOCK(kn->kn_kq);
2077 kn->kn_knlist = knl;
2078 kn->kn_status &= ~KN_DETACHED;
2079 KQ_UNLOCK(kn->kn_kq);
2080 }
2081
2082 static void
2083 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked,
2084 int kqislocked)
2085 {
2086 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked"));
2087 KNL_ASSERT_LOCK(knl, knlislocked);
2088 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED);
2089 if (!kqislocked)
2090 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX,
2091 ("knlist_remove called w/o knote being KN_INFLUX or already removed"));
2092 if (!knlislocked)
2093 knl->kl_lock(knl->kl_lockarg);
2094 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
2095 kn->kn_knlist = NULL;
2096 if (!knlislocked)
2097 kn_list_unlock(knl);
2098 if (!kqislocked)
2099 KQ_LOCK(kn->kn_kq);
2100 kn->kn_status |= KN_DETACHED;
2101 if (!kqislocked)
2102 KQ_UNLOCK(kn->kn_kq);
2103 }
2104
2105 /*
2106 * remove knote from the specified knlist
2107 */
2108 void
2109 knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
2110 {
2111
2112 knlist_remove_kq(knl, kn, islocked, 0);
2113 }
2114
2115 int
2116 knlist_empty(struct knlist *knl)
2117 {
2118
2119 KNL_ASSERT_LOCKED(knl);
2120 return (SLIST_EMPTY(&knl->kl_list));
2121 }
2122
2123 static struct mtx knlist_lock;
2124 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects",
2125 MTX_DEF);
2126 static void knlist_mtx_lock(void *arg);
2127 static void knlist_mtx_unlock(void *arg);
2128
2129 static void
2130 knlist_mtx_lock(void *arg)
2131 {
2132
2133 mtx_lock((struct mtx *)arg);
2134 }
2135
2136 static void
2137 knlist_mtx_unlock(void *arg)
2138 {
2139
2140 mtx_unlock((struct mtx *)arg);
2141 }
2142
2143 static void
2144 knlist_mtx_assert_locked(void *arg)
2145 {
2146
2147 mtx_assert((struct mtx *)arg, MA_OWNED);
2148 }
2149
2150 static void
2151 knlist_mtx_assert_unlocked(void *arg)
2152 {
2153
2154 mtx_assert((struct mtx *)arg, MA_NOTOWNED);
2155 }
2156
2157 static void
2158 knlist_rw_rlock(void *arg)
2159 {
2160
2161 rw_rlock((struct rwlock *)arg);
2162 }
2163
2164 static void
2165 knlist_rw_runlock(void *arg)
2166 {
2167
2168 rw_runlock((struct rwlock *)arg);
2169 }
2170
2171 static void
2172 knlist_rw_assert_locked(void *arg)
2173 {
2174
2175 rw_assert((struct rwlock *)arg, RA_LOCKED);
2176 }
2177
2178 static void
2179 knlist_rw_assert_unlocked(void *arg)
2180 {
2181
2182 rw_assert((struct rwlock *)arg, RA_UNLOCKED);
2183 }
2184
2185 void
2186 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
2187 void (*kl_unlock)(void *),
2188 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *))
2189 {
2190
2191 if (lock == NULL)
2192 knl->kl_lockarg = &knlist_lock;
2193 else
2194 knl->kl_lockarg = lock;
2195
2196 if (kl_lock == NULL)
2197 knl->kl_lock = knlist_mtx_lock;
2198 else
2199 knl->kl_lock = kl_lock;
2200 if (kl_unlock == NULL)
2201 knl->kl_unlock = knlist_mtx_unlock;
2202 else
2203 knl->kl_unlock = kl_unlock;
2204 if (kl_assert_locked == NULL)
2205 knl->kl_assert_locked = knlist_mtx_assert_locked;
2206 else
2207 knl->kl_assert_locked = kl_assert_locked;
2208 if (kl_assert_unlocked == NULL)
2209 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked;
2210 else
2211 knl->kl_assert_unlocked = kl_assert_unlocked;
2212
2213 knl->kl_autodestroy = 0;
2214 SLIST_INIT(&knl->kl_list);
2215 }
2216
2217 void
2218 knlist_init_mtx(struct knlist *knl, struct mtx *lock)
2219 {
2220
2221 knlist_init(knl, lock, NULL, NULL, NULL, NULL);
2222 }
2223
2224 struct knlist *
2225 knlist_alloc(struct mtx *lock)
2226 {
2227 struct knlist *knl;
2228
2229 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK);
2230 knlist_init_mtx(knl, lock);
2231 return (knl);
2232 }
2233
2234 void
2235 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock)
2236 {
2237
2238 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock,
2239 knlist_rw_assert_locked, knlist_rw_assert_unlocked);
2240 }
2241
2242 void
2243 knlist_destroy(struct knlist *knl)
2244 {
2245
2246 KASSERT(KNLIST_EMPTY(knl),
2247 ("destroying knlist %p with knotes on it", knl));
2248 }
2249
2250 void
2251 knlist_detach(struct knlist *knl)
2252 {
2253
2254 KNL_ASSERT_LOCKED(knl);
2255 knl->kl_autodestroy = 1;
2256 if (knlist_empty(knl)) {
2257 knlist_destroy(knl);
2258 free(knl, M_KQUEUE);
2259 }
2260 }
2261
2262 /*
2263 * Even if we are locked, we may need to drop the lock to allow any influx
2264 * knotes time to "settle".
2265 */
2266 void
2267 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
2268 {
2269 struct knote *kn, *kn2;
2270 struct kqueue *kq;
2271
2272 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl));
2273 if (islocked)
2274 KNL_ASSERT_LOCKED(knl);
2275 else {
2276 KNL_ASSERT_UNLOCKED(knl);
2277 again: /* need to reacquire lock since we have dropped it */
2278 knl->kl_lock(knl->kl_lockarg);
2279 }
2280
2281 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
2282 kq = kn->kn_kq;
2283 KQ_LOCK(kq);
2284 if ((kn->kn_status & KN_INFLUX)) {
2285 KQ_UNLOCK(kq);
2286 continue;
2287 }
2288 knlist_remove_kq(knl, kn, 1, 1);
2289 if (killkn) {
2290 kn->kn_status |= KN_INFLUX | KN_DETACHED;
2291 KQ_UNLOCK(kq);
2292 knote_drop(kn, td);
2293 } else {
2294 /* Make sure cleared knotes disappear soon */
2295 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
2296 KQ_UNLOCK(kq);
2297 }
2298 kq = NULL;
2299 }
2300
2301 if (!SLIST_EMPTY(&knl->kl_list)) {
2302 /* there are still KN_INFLUX remaining */
2303 kn = SLIST_FIRST(&knl->kl_list);
2304 kq = kn->kn_kq;
2305 KQ_LOCK(kq);
2306 KASSERT(kn->kn_status & KN_INFLUX,
2307 ("knote removed w/o list lock"));
2308 knl->kl_unlock(knl->kl_lockarg);
2309 kq->kq_state |= KQ_FLUXWAIT;
2310 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
2311 kq = NULL;
2312 goto again;
2313 }
2314
2315 if (islocked)
2316 KNL_ASSERT_LOCKED(knl);
2317 else {
2318 knl->kl_unlock(knl->kl_lockarg);
2319 KNL_ASSERT_UNLOCKED(knl);
2320 }
2321 }
2322
2323 /*
2324 * Remove all knotes referencing a specified fd must be called with FILEDESC
2325 * lock. This prevents a race where a new fd comes along and occupies the
2326 * entry and we attach a knote to the fd.
2327 */
2328 void
2329 knote_fdclose(struct thread *td, int fd)
2330 {
2331 struct filedesc *fdp = td->td_proc->p_fd;
2332 struct kqueue *kq;
2333 struct knote *kn;
2334 int influx;
2335
2336 FILEDESC_XLOCK_ASSERT(fdp);
2337
2338 /*
2339 * We shouldn't have to worry about new kevents appearing on fd
2340 * since filedesc is locked.
2341 */
2342 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
2343 KQ_LOCK(kq);
2344
2345 again:
2346 influx = 0;
2347 while (kq->kq_knlistsize > fd &&
2348 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
2349 if (kn->kn_status & KN_INFLUX) {
2350 /* someone else might be waiting on our knote */
2351 if (influx)
2352 wakeup(kq);
2353 kq->kq_state |= KQ_FLUXWAIT;
2354 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
2355 goto again;
2356 }
2357 kn->kn_status |= KN_INFLUX;
2358 KQ_UNLOCK(kq);
2359 if (!(kn->kn_status & KN_DETACHED))
2360 kn->kn_fop->f_detach(kn);
2361 knote_drop(kn, td);
2362 influx = 1;
2363 KQ_LOCK(kq);
2364 }
2365 KQ_UNLOCK_FLUX(kq);
2366 }
2367 }
2368
2369 static int
2370 knote_attach(struct knote *kn, struct kqueue *kq)
2371 {
2372 struct klist *list;
2373
2374 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX"));
2375 KQ_OWNED(kq);
2376
2377 if (kn->kn_fop->f_isfd) {
2378 if (kn->kn_id >= kq->kq_knlistsize)
2379 return (ENOMEM);
2380 list = &kq->kq_knlist[kn->kn_id];
2381 } else {
2382 if (kq->kq_knhash == NULL)
2383 return (ENOMEM);
2384 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2385 }
2386 SLIST_INSERT_HEAD(list, kn, kn_link);
2387 return (0);
2388 }
2389
2390 /*
2391 * knote must already have been detached using the f_detach method.
2392 * no lock need to be held, it is assumed that the KN_INFLUX flag is set
2393 * to prevent other removal.
2394 */
2395 static void
2396 knote_drop(struct knote *kn, struct thread *td)
2397 {
2398 struct kqueue *kq;
2399 struct klist *list;
2400
2401 kq = kn->kn_kq;
2402
2403 KQ_NOTOWNED(kq);
2404 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX,
2405 ("knote_drop called without KN_INFLUX set in kn_status"));
2406
2407 KQ_LOCK(kq);
2408 if (kn->kn_fop->f_isfd)
2409 list = &kq->kq_knlist[kn->kn_id];
2410 else
2411 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2412
2413 if (!SLIST_EMPTY(list))
2414 SLIST_REMOVE(list, kn, knote, kn_link);
2415 if (kn->kn_status & KN_QUEUED)
2416 knote_dequeue(kn);
2417 KQ_UNLOCK_FLUX(kq);
2418
2419 if (kn->kn_fop->f_isfd) {
2420 fdrop(kn->kn_fp, td);
2421 kn->kn_fp = NULL;
2422 }
2423 kqueue_fo_release(kn->kn_kevent.filter);
2424 kn->kn_fop = NULL;
2425 knote_free(kn);
2426 }
2427
2428 static void
2429 knote_enqueue(struct knote *kn)
2430 {
2431 struct kqueue *kq = kn->kn_kq;
2432
2433 KQ_OWNED(kn->kn_kq);
2434 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
2435
2436 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
2437 kn->kn_status |= KN_QUEUED;
2438 kq->kq_count++;
2439 kqueue_wakeup(kq);
2440 }
2441
2442 static void
2443 knote_dequeue(struct knote *kn)
2444 {
2445 struct kqueue *kq = kn->kn_kq;
2446
2447 KQ_OWNED(kn->kn_kq);
2448 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
2449
2450 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
2451 kn->kn_status &= ~KN_QUEUED;
2452 kq->kq_count--;
2453 }
2454
2455 static void
2456 knote_init(void)
2457 {
2458
2459 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
2460 NULL, NULL, UMA_ALIGN_PTR, 0);
2461 }
2462 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
2463
2464 static struct knote *
2465 knote_alloc(int waitok)
2466 {
2467
2468 return (uma_zalloc(knote_zone, (waitok ? M_WAITOK : M_NOWAIT) |
2469 M_ZERO));
2470 }
2471
2472 static void
2473 knote_free(struct knote *kn)
2474 {
2475
2476 uma_zfree(knote_zone, kn);
2477 }
2478
2479 /*
2480 * Register the kev w/ the kq specified by fd.
2481 */
2482 int
2483 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok)
2484 {
2485 struct kqueue *kq;
2486 struct file *fp;
2487 cap_rights_t rights;
2488 int error;
2489
2490 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp);
2491 if (error != 0)
2492 return (error);
2493 if ((error = kqueue_acquire(fp, &kq)) != 0)
2494 goto noacquire;
2495
2496 error = kqueue_register(kq, kev, td, waitok);
2497 kqueue_release(kq, 0);
2498
2499 noacquire:
2500 fdrop(fp, td);
2501 return (error);
2502 }
Cache object: 668a4826b16eea94f05e7c3c95a744a9
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