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/11.0/sys/kern/kern_event.c 303216 2016-07-23 08:23:57Z kib $");
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/stdatomic.h>
52 #include <sys/queue.h>
53 #include <sys/event.h>
54 #include <sys/eventvar.h>
55 #include <sys/poll.h>
56 #include <sys/protosw.h>
57 #include <sys/resourcevar.h>
58 #include <sys/sigio.h>
59 #include <sys/signalvar.h>
60 #include <sys/socket.h>
61 #include <sys/socketvar.h>
62 #include <sys/stat.h>
63 #include <sys/sysctl.h>
64 #include <sys/sysproto.h>
65 #include <sys/syscallsubr.h>
66 #include <sys/taskqueue.h>
67 #include <sys/uio.h>
68 #include <sys/user.h>
69 #ifdef KTRACE
70 #include <sys/ktrace.h>
71 #endif
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 atomic_uint kq_ncallouts = ATOMIC_VAR_INIT(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 (NOTE_SECONDS|NOTE_MSECONDS|NOTE_USECONDS| \
577 NOTE_NSECONDS)
578
579 static sbintime_t
580 timer2sbintime(intptr_t data, int flags)
581 {
582
583 /*
584 * Macros for converting to the fractional second portion of an
585 * sbintime_t using 64bit multiplication to improve precision.
586 */
587 #define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32)
588 #define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32)
589 #define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32)
590 switch (flags & NOTE_TIMER_PRECMASK) {
591 case NOTE_SECONDS:
592 #ifdef __LP64__
593 if (data > (SBT_MAX / SBT_1S))
594 return SBT_MAX;
595 #endif
596 return ((sbintime_t)data << 32);
597 case NOTE_MSECONDS: /* FALLTHROUGH */
598 case 0:
599 if (data >= 1000) {
600 int64_t secs = data / 1000;
601 #ifdef __LP64__
602 if (secs > (SBT_MAX / SBT_1S))
603 return SBT_MAX;
604 #endif
605 return (secs << 32 | MS_TO_SBT(data % 1000));
606 }
607 return MS_TO_SBT(data);
608 case NOTE_USECONDS:
609 if (data >= 1000000) {
610 int64_t secs = data / 1000000;
611 #ifdef __LP64__
612 if (secs > (SBT_MAX / SBT_1S))
613 return SBT_MAX;
614 #endif
615 return (secs << 32 | US_TO_SBT(data % 1000000));
616 }
617 return US_TO_SBT(data);
618 case NOTE_NSECONDS:
619 if (data >= 1000000000) {
620 int64_t secs = data / 1000000000;
621 #ifdef __LP64__
622 if (secs > (SBT_MAX / SBT_1S))
623 return SBT_MAX;
624 #endif
625 return (secs << 32 | US_TO_SBT(data % 1000000000));
626 }
627 return NS_TO_SBT(data);
628 default:
629 break;
630 }
631 return (-1);
632 }
633
634 static void
635 filt_timerexpire(void *knx)
636 {
637 struct callout *calloutp;
638 struct knote *kn;
639
640 kn = knx;
641 kn->kn_data++;
642 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
643
644 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) {
645 calloutp = (struct callout *)kn->kn_hook;
646 *kn->kn_ptr.p_nexttime += timer2sbintime(kn->kn_sdata,
647 kn->kn_sfflags);
648 callout_reset_sbt_on(calloutp, *kn->kn_ptr.p_nexttime, 0,
649 filt_timerexpire, kn, PCPU_GET(cpuid), C_ABSOLUTE);
650 }
651 }
652
653 /*
654 * data contains amount of time to sleep
655 */
656 static int
657 filt_timerattach(struct knote *kn)
658 {
659 struct callout *calloutp;
660 sbintime_t to;
661 unsigned int ncallouts;
662
663 if ((intptr_t)kn->kn_sdata < 0)
664 return (EINVAL);
665 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0)
666 kn->kn_sdata = 1;
667 /* Only precision unit are supported in flags so far */
668 if (kn->kn_sfflags & ~NOTE_TIMER_PRECMASK)
669 return (EINVAL);
670
671 to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags);
672 if (to < 0)
673 return (EINVAL);
674
675 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed);
676 do {
677 if (ncallouts >= kq_calloutmax)
678 return (ENOMEM);
679 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts,
680 &ncallouts, ncallouts + 1, memory_order_relaxed,
681 memory_order_relaxed));
682
683 kn->kn_flags |= EV_CLEAR; /* automatically set */
684 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */
685 kn->kn_ptr.p_nexttime = malloc(sizeof(sbintime_t), M_KQUEUE, M_WAITOK);
686 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK);
687 callout_init(calloutp, 1);
688 kn->kn_hook = calloutp;
689 *kn->kn_ptr.p_nexttime = to + sbinuptime();
690 callout_reset_sbt_on(calloutp, *kn->kn_ptr.p_nexttime, 0,
691 filt_timerexpire, kn, PCPU_GET(cpuid), C_ABSOLUTE);
692
693 return (0);
694 }
695
696 static void
697 filt_timerdetach(struct knote *kn)
698 {
699 struct callout *calloutp;
700 unsigned int old;
701
702 calloutp = (struct callout *)kn->kn_hook;
703 callout_drain(calloutp);
704 free(calloutp, M_KQUEUE);
705 free(kn->kn_ptr.p_nexttime, M_KQUEUE);
706 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed);
707 KASSERT(old > 0, ("Number of callouts cannot become negative"));
708 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */
709 }
710
711 static int
712 filt_timer(struct knote *kn, long hint)
713 {
714
715 return (kn->kn_data != 0);
716 }
717
718 static int
719 filt_userattach(struct knote *kn)
720 {
721
722 /*
723 * EVFILT_USER knotes are not attached to anything in the kernel.
724 */
725 kn->kn_hook = NULL;
726 if (kn->kn_fflags & NOTE_TRIGGER)
727 kn->kn_hookid = 1;
728 else
729 kn->kn_hookid = 0;
730 return (0);
731 }
732
733 static void
734 filt_userdetach(__unused struct knote *kn)
735 {
736
737 /*
738 * EVFILT_USER knotes are not attached to anything in the kernel.
739 */
740 }
741
742 static int
743 filt_user(struct knote *kn, __unused long hint)
744 {
745
746 return (kn->kn_hookid);
747 }
748
749 static void
750 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
751 {
752 u_int ffctrl;
753
754 switch (type) {
755 case EVENT_REGISTER:
756 if (kev->fflags & NOTE_TRIGGER)
757 kn->kn_hookid = 1;
758
759 ffctrl = kev->fflags & NOTE_FFCTRLMASK;
760 kev->fflags &= NOTE_FFLAGSMASK;
761 switch (ffctrl) {
762 case NOTE_FFNOP:
763 break;
764
765 case NOTE_FFAND:
766 kn->kn_sfflags &= kev->fflags;
767 break;
768
769 case NOTE_FFOR:
770 kn->kn_sfflags |= kev->fflags;
771 break;
772
773 case NOTE_FFCOPY:
774 kn->kn_sfflags = kev->fflags;
775 break;
776
777 default:
778 /* XXX Return error? */
779 break;
780 }
781 kn->kn_sdata = kev->data;
782 if (kev->flags & EV_CLEAR) {
783 kn->kn_hookid = 0;
784 kn->kn_data = 0;
785 kn->kn_fflags = 0;
786 }
787 break;
788
789 case EVENT_PROCESS:
790 *kev = kn->kn_kevent;
791 kev->fflags = kn->kn_sfflags;
792 kev->data = kn->kn_sdata;
793 if (kn->kn_flags & EV_CLEAR) {
794 kn->kn_hookid = 0;
795 kn->kn_data = 0;
796 kn->kn_fflags = 0;
797 }
798 break;
799
800 default:
801 panic("filt_usertouch() - invalid type (%ld)", type);
802 break;
803 }
804 }
805
806 int
807 sys_kqueue(struct thread *td, struct kqueue_args *uap)
808 {
809
810 return (kern_kqueue(td, 0, NULL));
811 }
812
813 static void
814 kqueue_init(struct kqueue *kq)
815 {
816
817 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK);
818 TAILQ_INIT(&kq->kq_head);
819 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
820 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
821 }
822
823 int
824 kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps)
825 {
826 struct filedesc *fdp;
827 struct kqueue *kq;
828 struct file *fp;
829 struct ucred *cred;
830 int fd, error;
831
832 fdp = td->td_proc->p_fd;
833 cred = td->td_ucred;
834 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES)))
835 return (ENOMEM);
836
837 error = falloc_caps(td, &fp, &fd, flags, fcaps);
838 if (error != 0) {
839 chgkqcnt(cred->cr_ruidinfo, -1, 0);
840 return (error);
841 }
842
843 /* An extra reference on `fp' has been held for us by falloc(). */
844 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
845 kqueue_init(kq);
846 kq->kq_fdp = fdp;
847 kq->kq_cred = crhold(cred);
848
849 FILEDESC_XLOCK(fdp);
850 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
851 FILEDESC_XUNLOCK(fdp);
852
853 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
854 fdrop(fp, td);
855
856 td->td_retval[0] = fd;
857 return (0);
858 }
859
860 #ifndef _SYS_SYSPROTO_H_
861 struct kevent_args {
862 int fd;
863 const struct kevent *changelist;
864 int nchanges;
865 struct kevent *eventlist;
866 int nevents;
867 const struct timespec *timeout;
868 };
869 #endif
870 int
871 sys_kevent(struct thread *td, struct kevent_args *uap)
872 {
873 struct timespec ts, *tsp;
874 struct kevent_copyops k_ops = { uap,
875 kevent_copyout,
876 kevent_copyin};
877 int error;
878 #ifdef KTRACE
879 struct uio ktruio;
880 struct iovec ktriov;
881 struct uio *ktruioin = NULL;
882 struct uio *ktruioout = NULL;
883 #endif
884
885 if (uap->timeout != NULL) {
886 error = copyin(uap->timeout, &ts, sizeof(ts));
887 if (error)
888 return (error);
889 tsp = &ts;
890 } else
891 tsp = NULL;
892
893 #ifdef KTRACE
894 if (KTRPOINT(td, KTR_GENIO)) {
895 ktriov.iov_base = uap->changelist;
896 ktriov.iov_len = uap->nchanges * sizeof(struct kevent);
897 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1,
898 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ,
899 .uio_td = td };
900 ktruioin = cloneuio(&ktruio);
901 ktriov.iov_base = uap->eventlist;
902 ktriov.iov_len = uap->nevents * sizeof(struct kevent);
903 ktruioout = cloneuio(&ktruio);
904 }
905 #endif
906
907 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
908 &k_ops, tsp);
909
910 #ifdef KTRACE
911 if (ktruioin != NULL) {
912 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent);
913 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0);
914 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent);
915 ktrgenio(uap->fd, UIO_READ, ktruioout, error);
916 }
917 #endif
918
919 return (error);
920 }
921
922 /*
923 * Copy 'count' items into the destination list pointed to by uap->eventlist.
924 */
925 static int
926 kevent_copyout(void *arg, struct kevent *kevp, int count)
927 {
928 struct kevent_args *uap;
929 int error;
930
931 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
932 uap = (struct kevent_args *)arg;
933
934 error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
935 if (error == 0)
936 uap->eventlist += count;
937 return (error);
938 }
939
940 /*
941 * Copy 'count' items from the list pointed to by uap->changelist.
942 */
943 static int
944 kevent_copyin(void *arg, struct kevent *kevp, int count)
945 {
946 struct kevent_args *uap;
947 int error;
948
949 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
950 uap = (struct kevent_args *)arg;
951
952 error = copyin(uap->changelist, kevp, count * sizeof *kevp);
953 if (error == 0)
954 uap->changelist += count;
955 return (error);
956 }
957
958 int
959 kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
960 struct kevent_copyops *k_ops, const struct timespec *timeout)
961 {
962 cap_rights_t rights;
963 struct file *fp;
964 int error;
965
966 cap_rights_init(&rights);
967 if (nchanges > 0)
968 cap_rights_set(&rights, CAP_KQUEUE_CHANGE);
969 if (nevents > 0)
970 cap_rights_set(&rights, CAP_KQUEUE_EVENT);
971 error = fget(td, fd, &rights, &fp);
972 if (error != 0)
973 return (error);
974
975 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout);
976 fdrop(fp, td);
977
978 return (error);
979 }
980
981 static int
982 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents,
983 struct kevent_copyops *k_ops, const struct timespec *timeout)
984 {
985 struct kevent keva[KQ_NEVENTS];
986 struct kevent *kevp, *changes;
987 int i, n, nerrors, error;
988
989 nerrors = 0;
990 while (nchanges > 0) {
991 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
992 error = k_ops->k_copyin(k_ops->arg, keva, n);
993 if (error)
994 return (error);
995 changes = keva;
996 for (i = 0; i < n; i++) {
997 kevp = &changes[i];
998 if (!kevp->filter)
999 continue;
1000 kevp->flags &= ~EV_SYSFLAGS;
1001 error = kqueue_register(kq, kevp, td, 1);
1002 if (error || (kevp->flags & EV_RECEIPT)) {
1003 if (nevents == 0)
1004 return (error);
1005 kevp->flags = EV_ERROR;
1006 kevp->data = error;
1007 (void)k_ops->k_copyout(k_ops->arg, kevp, 1);
1008 nevents--;
1009 nerrors++;
1010 }
1011 }
1012 nchanges -= n;
1013 }
1014 if (nerrors) {
1015 td->td_retval[0] = nerrors;
1016 return (0);
1017 }
1018
1019 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td));
1020 }
1021
1022 int
1023 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents,
1024 struct kevent_copyops *k_ops, const struct timespec *timeout)
1025 {
1026 struct kqueue *kq;
1027 int error;
1028
1029 error = kqueue_acquire(fp, &kq);
1030 if (error != 0)
1031 return (error);
1032 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout);
1033 kqueue_release(kq, 0);
1034 return (error);
1035 }
1036
1037 /*
1038 * Performs a kevent() call on a temporarily created kqueue. This can be
1039 * used to perform one-shot polling, similar to poll() and select().
1040 */
1041 int
1042 kern_kevent_anonymous(struct thread *td, int nevents,
1043 struct kevent_copyops *k_ops)
1044 {
1045 struct kqueue kq = {};
1046 int error;
1047
1048 kqueue_init(&kq);
1049 kq.kq_refcnt = 1;
1050 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL);
1051 kqueue_drain(&kq, td);
1052 kqueue_destroy(&kq);
1053 return (error);
1054 }
1055
1056 int
1057 kqueue_add_filteropts(int filt, struct filterops *filtops)
1058 {
1059 int error;
1060
1061 error = 0;
1062 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
1063 printf(
1064 "trying to add a filterop that is out of range: %d is beyond %d\n",
1065 ~filt, EVFILT_SYSCOUNT);
1066 return EINVAL;
1067 }
1068 mtx_lock(&filterops_lock);
1069 if (sysfilt_ops[~filt].for_fop != &null_filtops &&
1070 sysfilt_ops[~filt].for_fop != NULL)
1071 error = EEXIST;
1072 else {
1073 sysfilt_ops[~filt].for_fop = filtops;
1074 sysfilt_ops[~filt].for_refcnt = 0;
1075 }
1076 mtx_unlock(&filterops_lock);
1077
1078 return (error);
1079 }
1080
1081 int
1082 kqueue_del_filteropts(int filt)
1083 {
1084 int error;
1085
1086 error = 0;
1087 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1088 return EINVAL;
1089
1090 mtx_lock(&filterops_lock);
1091 if (sysfilt_ops[~filt].for_fop == &null_filtops ||
1092 sysfilt_ops[~filt].for_fop == NULL)
1093 error = EINVAL;
1094 else if (sysfilt_ops[~filt].for_refcnt != 0)
1095 error = EBUSY;
1096 else {
1097 sysfilt_ops[~filt].for_fop = &null_filtops;
1098 sysfilt_ops[~filt].for_refcnt = 0;
1099 }
1100 mtx_unlock(&filterops_lock);
1101
1102 return error;
1103 }
1104
1105 static struct filterops *
1106 kqueue_fo_find(int filt)
1107 {
1108
1109 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1110 return NULL;
1111
1112 if (sysfilt_ops[~filt].for_nolock)
1113 return sysfilt_ops[~filt].for_fop;
1114
1115 mtx_lock(&filterops_lock);
1116 sysfilt_ops[~filt].for_refcnt++;
1117 if (sysfilt_ops[~filt].for_fop == NULL)
1118 sysfilt_ops[~filt].for_fop = &null_filtops;
1119 mtx_unlock(&filterops_lock);
1120
1121 return sysfilt_ops[~filt].for_fop;
1122 }
1123
1124 static void
1125 kqueue_fo_release(int filt)
1126 {
1127
1128 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1129 return;
1130
1131 if (sysfilt_ops[~filt].for_nolock)
1132 return;
1133
1134 mtx_lock(&filterops_lock);
1135 KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
1136 ("filter object refcount not valid on release"));
1137 sysfilt_ops[~filt].for_refcnt--;
1138 mtx_unlock(&filterops_lock);
1139 }
1140
1141 /*
1142 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will
1143 * influence if memory allocation should wait. Make sure it is 0 if you
1144 * hold any mutexes.
1145 */
1146 static int
1147 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok)
1148 {
1149 struct filterops *fops;
1150 struct file *fp;
1151 struct knote *kn, *tkn;
1152 struct knlist *knl;
1153 cap_rights_t rights;
1154 int error, filt, event;
1155 int haskqglobal, filedesc_unlock;
1156
1157 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE))
1158 return (EINVAL);
1159
1160 fp = NULL;
1161 kn = NULL;
1162 knl = NULL;
1163 error = 0;
1164 haskqglobal = 0;
1165 filedesc_unlock = 0;
1166
1167 filt = kev->filter;
1168 fops = kqueue_fo_find(filt);
1169 if (fops == NULL)
1170 return EINVAL;
1171
1172 if (kev->flags & EV_ADD) {
1173 /*
1174 * Prevent waiting with locks. Non-sleepable
1175 * allocation failures are handled in the loop, only
1176 * if the spare knote appears to be actually required.
1177 */
1178 tkn = knote_alloc(waitok);
1179 } else {
1180 tkn = NULL;
1181 }
1182
1183 findkn:
1184 if (fops->f_isfd) {
1185 KASSERT(td != NULL, ("td is NULL"));
1186 if (kev->ident > INT_MAX)
1187 error = EBADF;
1188 else
1189 error = fget(td, kev->ident,
1190 cap_rights_init(&rights, CAP_EVENT), &fp);
1191 if (error)
1192 goto done;
1193
1194 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
1195 kev->ident, 0) != 0) {
1196 /* try again */
1197 fdrop(fp, td);
1198 fp = NULL;
1199 error = kqueue_expand(kq, fops, kev->ident, waitok);
1200 if (error)
1201 goto done;
1202 goto findkn;
1203 }
1204
1205 if (fp->f_type == DTYPE_KQUEUE) {
1206 /*
1207 * If we add some intelligence about what we are doing,
1208 * we should be able to support events on ourselves.
1209 * We need to know when we are doing this to prevent
1210 * getting both the knlist lock and the kq lock since
1211 * they are the same thing.
1212 */
1213 if (fp->f_data == kq) {
1214 error = EINVAL;
1215 goto done;
1216 }
1217
1218 /*
1219 * Pre-lock the filedesc before the global
1220 * lock mutex, see the comment in
1221 * kqueue_close().
1222 */
1223 FILEDESC_XLOCK(td->td_proc->p_fd);
1224 filedesc_unlock = 1;
1225 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1226 }
1227
1228 KQ_LOCK(kq);
1229 if (kev->ident < kq->kq_knlistsize) {
1230 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
1231 if (kev->filter == kn->kn_filter)
1232 break;
1233 }
1234 } else {
1235 if ((kev->flags & EV_ADD) == EV_ADD)
1236 kqueue_expand(kq, fops, kev->ident, waitok);
1237
1238 KQ_LOCK(kq);
1239
1240 /*
1241 * If possible, find an existing knote to use for this kevent.
1242 */
1243 if (kev->filter == EVFILT_PROC &&
1244 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) {
1245 /* This is an internal creation of a process tracking
1246 * note. Don't attempt to coalesce this with an
1247 * existing note.
1248 */
1249 ;
1250 } else if (kq->kq_knhashmask != 0) {
1251 struct klist *list;
1252
1253 list = &kq->kq_knhash[
1254 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
1255 SLIST_FOREACH(kn, list, kn_link)
1256 if (kev->ident == kn->kn_id &&
1257 kev->filter == kn->kn_filter)
1258 break;
1259 }
1260 }
1261
1262 /* knote is in the process of changing, wait for it to stabilize. */
1263 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1264 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1265 if (filedesc_unlock) {
1266 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1267 filedesc_unlock = 0;
1268 }
1269 kq->kq_state |= KQ_FLUXWAIT;
1270 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
1271 if (fp != NULL) {
1272 fdrop(fp, td);
1273 fp = NULL;
1274 }
1275 goto findkn;
1276 }
1277
1278 /*
1279 * kn now contains the matching knote, or NULL if no match
1280 */
1281 if (kn == NULL) {
1282 if (kev->flags & EV_ADD) {
1283 kn = tkn;
1284 tkn = NULL;
1285 if (kn == NULL) {
1286 KQ_UNLOCK(kq);
1287 error = ENOMEM;
1288 goto done;
1289 }
1290 kn->kn_fp = fp;
1291 kn->kn_kq = kq;
1292 kn->kn_fop = fops;
1293 /*
1294 * apply reference counts to knote structure, and
1295 * do not release it at the end of this routine.
1296 */
1297 fops = NULL;
1298 fp = NULL;
1299
1300 kn->kn_sfflags = kev->fflags;
1301 kn->kn_sdata = kev->data;
1302 kev->fflags = 0;
1303 kev->data = 0;
1304 kn->kn_kevent = *kev;
1305 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
1306 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT);
1307 kn->kn_status = KN_INFLUX|KN_DETACHED;
1308
1309 error = knote_attach(kn, kq);
1310 KQ_UNLOCK(kq);
1311 if (error != 0) {
1312 tkn = kn;
1313 goto done;
1314 }
1315
1316 if ((error = kn->kn_fop->f_attach(kn)) != 0) {
1317 knote_drop(kn, td);
1318 goto done;
1319 }
1320 knl = kn_list_lock(kn);
1321 goto done_ev_add;
1322 } else {
1323 /* No matching knote and the EV_ADD flag is not set. */
1324 KQ_UNLOCK(kq);
1325 error = ENOENT;
1326 goto done;
1327 }
1328 }
1329
1330 if (kev->flags & EV_DELETE) {
1331 kn->kn_status |= KN_INFLUX;
1332 KQ_UNLOCK(kq);
1333 if (!(kn->kn_status & KN_DETACHED))
1334 kn->kn_fop->f_detach(kn);
1335 knote_drop(kn, td);
1336 goto done;
1337 }
1338
1339 if (kev->flags & EV_FORCEONESHOT) {
1340 kn->kn_flags |= EV_ONESHOT;
1341 KNOTE_ACTIVATE(kn, 1);
1342 }
1343
1344 /*
1345 * The user may change some filter values after the initial EV_ADD,
1346 * but doing so will not reset any filter which has already been
1347 * triggered.
1348 */
1349 kn->kn_status |= KN_INFLUX | KN_SCAN;
1350 KQ_UNLOCK(kq);
1351 knl = kn_list_lock(kn);
1352 kn->kn_kevent.udata = kev->udata;
1353 if (!fops->f_isfd && fops->f_touch != NULL) {
1354 fops->f_touch(kn, kev, EVENT_REGISTER);
1355 } else {
1356 kn->kn_sfflags = kev->fflags;
1357 kn->kn_sdata = kev->data;
1358 }
1359
1360 /*
1361 * We can get here with kn->kn_knlist == NULL. This can happen when
1362 * the initial attach event decides that the event is "completed"
1363 * already. i.e. filt_procattach is called on a zombie process. It
1364 * will call filt_proc which will remove it from the list, and NULL
1365 * kn_knlist.
1366 */
1367 done_ev_add:
1368 if ((kev->flags & EV_ENABLE) != 0)
1369 kn->kn_status &= ~KN_DISABLED;
1370 else if ((kev->flags & EV_DISABLE) != 0)
1371 kn->kn_status |= KN_DISABLED;
1372
1373 if ((kn->kn_status & KN_DISABLED) == 0)
1374 event = kn->kn_fop->f_event(kn, 0);
1375 else
1376 event = 0;
1377
1378 KQ_LOCK(kq);
1379 if (event)
1380 kn->kn_status |= KN_ACTIVE;
1381 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) ==
1382 KN_ACTIVE)
1383 knote_enqueue(kn);
1384 kn->kn_status &= ~(KN_INFLUX | KN_SCAN);
1385 kn_list_unlock(knl);
1386 KQ_UNLOCK_FLUX(kq);
1387
1388 done:
1389 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1390 if (filedesc_unlock)
1391 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1392 if (fp != NULL)
1393 fdrop(fp, td);
1394 knote_free(tkn);
1395 if (fops != NULL)
1396 kqueue_fo_release(filt);
1397 return (error);
1398 }
1399
1400 static int
1401 kqueue_acquire(struct file *fp, struct kqueue **kqp)
1402 {
1403 int error;
1404 struct kqueue *kq;
1405
1406 error = 0;
1407
1408 kq = fp->f_data;
1409 if (fp->f_type != DTYPE_KQUEUE || kq == NULL)
1410 return (EBADF);
1411 *kqp = kq;
1412 KQ_LOCK(kq);
1413 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
1414 KQ_UNLOCK(kq);
1415 return (EBADF);
1416 }
1417 kq->kq_refcnt++;
1418 KQ_UNLOCK(kq);
1419
1420 return error;
1421 }
1422
1423 static void
1424 kqueue_release(struct kqueue *kq, int locked)
1425 {
1426 if (locked)
1427 KQ_OWNED(kq);
1428 else
1429 KQ_LOCK(kq);
1430 kq->kq_refcnt--;
1431 if (kq->kq_refcnt == 1)
1432 wakeup(&kq->kq_refcnt);
1433 if (!locked)
1434 KQ_UNLOCK(kq);
1435 }
1436
1437 static void
1438 kqueue_schedtask(struct kqueue *kq)
1439 {
1440
1441 KQ_OWNED(kq);
1442 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
1443 ("scheduling kqueue task while draining"));
1444
1445 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
1446 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task);
1447 kq->kq_state |= KQ_TASKSCHED;
1448 }
1449 }
1450
1451 /*
1452 * Expand the kq to make sure we have storage for fops/ident pair.
1453 *
1454 * Return 0 on success (or no work necessary), return errno on failure.
1455 *
1456 * Not calling hashinit w/ waitok (proper malloc flag) should be safe.
1457 * If kqueue_register is called from a non-fd context, there usually/should
1458 * be no locks held.
1459 */
1460 static int
1461 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident,
1462 int waitok)
1463 {
1464 struct klist *list, *tmp_knhash, *to_free;
1465 u_long tmp_knhashmask;
1466 int size;
1467 int fd;
1468 int mflag = waitok ? M_WAITOK : M_NOWAIT;
1469
1470 KQ_NOTOWNED(kq);
1471
1472 to_free = NULL;
1473 if (fops->f_isfd) {
1474 fd = ident;
1475 if (kq->kq_knlistsize <= fd) {
1476 size = kq->kq_knlistsize;
1477 while (size <= fd)
1478 size += KQEXTENT;
1479 list = malloc(size * sizeof(*list), M_KQUEUE, mflag);
1480 if (list == NULL)
1481 return ENOMEM;
1482 KQ_LOCK(kq);
1483 if (kq->kq_knlistsize > fd) {
1484 to_free = list;
1485 list = NULL;
1486 } else {
1487 if (kq->kq_knlist != NULL) {
1488 bcopy(kq->kq_knlist, list,
1489 kq->kq_knlistsize * sizeof(*list));
1490 to_free = kq->kq_knlist;
1491 kq->kq_knlist = NULL;
1492 }
1493 bzero((caddr_t)list +
1494 kq->kq_knlistsize * sizeof(*list),
1495 (size - kq->kq_knlistsize) * sizeof(*list));
1496 kq->kq_knlistsize = size;
1497 kq->kq_knlist = list;
1498 }
1499 KQ_UNLOCK(kq);
1500 }
1501 } else {
1502 if (kq->kq_knhashmask == 0) {
1503 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
1504 &tmp_knhashmask);
1505 if (tmp_knhash == NULL)
1506 return ENOMEM;
1507 KQ_LOCK(kq);
1508 if (kq->kq_knhashmask == 0) {
1509 kq->kq_knhash = tmp_knhash;
1510 kq->kq_knhashmask = tmp_knhashmask;
1511 } else {
1512 to_free = tmp_knhash;
1513 }
1514 KQ_UNLOCK(kq);
1515 }
1516 }
1517 free(to_free, M_KQUEUE);
1518
1519 KQ_NOTOWNED(kq);
1520 return 0;
1521 }
1522
1523 static void
1524 kqueue_task(void *arg, int pending)
1525 {
1526 struct kqueue *kq;
1527 int haskqglobal;
1528
1529 haskqglobal = 0;
1530 kq = arg;
1531
1532 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1533 KQ_LOCK(kq);
1534
1535 KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
1536
1537 kq->kq_state &= ~KQ_TASKSCHED;
1538 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
1539 wakeup(&kq->kq_state);
1540 }
1541 KQ_UNLOCK(kq);
1542 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1543 }
1544
1545 /*
1546 * Scan, update kn_data (if not ONESHOT), and copyout triggered events.
1547 * We treat KN_MARKER knotes as if they are INFLUX.
1548 */
1549 static int
1550 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
1551 const struct timespec *tsp, struct kevent *keva, struct thread *td)
1552 {
1553 struct kevent *kevp;
1554 struct knote *kn, *marker;
1555 struct knlist *knl;
1556 sbintime_t asbt, rsbt;
1557 int count, error, haskqglobal, influx, nkev, touch;
1558
1559 count = maxevents;
1560 nkev = 0;
1561 error = 0;
1562 haskqglobal = 0;
1563
1564 if (maxevents == 0)
1565 goto done_nl;
1566
1567 rsbt = 0;
1568 if (tsp != NULL) {
1569 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 ||
1570 tsp->tv_nsec >= 1000000000) {
1571 error = EINVAL;
1572 goto done_nl;
1573 }
1574 if (timespecisset(tsp)) {
1575 if (tsp->tv_sec <= INT32_MAX) {
1576 rsbt = tstosbt(*tsp);
1577 if (TIMESEL(&asbt, rsbt))
1578 asbt += tc_tick_sbt;
1579 if (asbt <= SBT_MAX - rsbt)
1580 asbt += rsbt;
1581 else
1582 asbt = 0;
1583 rsbt >>= tc_precexp;
1584 } else
1585 asbt = 0;
1586 } else
1587 asbt = -1;
1588 } else
1589 asbt = 0;
1590 marker = knote_alloc(1);
1591 marker->kn_status = KN_MARKER;
1592 KQ_LOCK(kq);
1593
1594 retry:
1595 kevp = keva;
1596 if (kq->kq_count == 0) {
1597 if (asbt == -1) {
1598 error = EWOULDBLOCK;
1599 } else {
1600 kq->kq_state |= KQ_SLEEP;
1601 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH,
1602 "kqread", asbt, rsbt, C_ABSOLUTE);
1603 }
1604 if (error == 0)
1605 goto retry;
1606 /* don't restart after signals... */
1607 if (error == ERESTART)
1608 error = EINTR;
1609 else if (error == EWOULDBLOCK)
1610 error = 0;
1611 goto done;
1612 }
1613
1614 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
1615 influx = 0;
1616 while (count) {
1617 KQ_OWNED(kq);
1618 kn = TAILQ_FIRST(&kq->kq_head);
1619
1620 if ((kn->kn_status == KN_MARKER && kn != marker) ||
1621 (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1622 if (influx) {
1623 influx = 0;
1624 KQ_FLUX_WAKEUP(kq);
1625 }
1626 kq->kq_state |= KQ_FLUXWAIT;
1627 error = msleep(kq, &kq->kq_lock, PSOCK,
1628 "kqflxwt", 0);
1629 continue;
1630 }
1631
1632 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
1633 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
1634 kn->kn_status &= ~KN_QUEUED;
1635 kq->kq_count--;
1636 continue;
1637 }
1638 if (kn == marker) {
1639 KQ_FLUX_WAKEUP(kq);
1640 if (count == maxevents)
1641 goto retry;
1642 goto done;
1643 }
1644 KASSERT((kn->kn_status & KN_INFLUX) == 0,
1645 ("KN_INFLUX set when not suppose to be"));
1646
1647 if ((kn->kn_flags & EV_DROP) == EV_DROP) {
1648 kn->kn_status &= ~KN_QUEUED;
1649 kn->kn_status |= KN_INFLUX;
1650 kq->kq_count--;
1651 KQ_UNLOCK(kq);
1652 /*
1653 * We don't need to lock the list since we've marked
1654 * it _INFLUX.
1655 */
1656 if (!(kn->kn_status & KN_DETACHED))
1657 kn->kn_fop->f_detach(kn);
1658 knote_drop(kn, td);
1659 KQ_LOCK(kq);
1660 continue;
1661 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
1662 kn->kn_status &= ~KN_QUEUED;
1663 kn->kn_status |= KN_INFLUX;
1664 kq->kq_count--;
1665 KQ_UNLOCK(kq);
1666 /*
1667 * We don't need to lock the list since we've marked
1668 * it _INFLUX.
1669 */
1670 *kevp = kn->kn_kevent;
1671 if (!(kn->kn_status & KN_DETACHED))
1672 kn->kn_fop->f_detach(kn);
1673 knote_drop(kn, td);
1674 KQ_LOCK(kq);
1675 kn = NULL;
1676 } else {
1677 kn->kn_status |= KN_INFLUX | KN_SCAN;
1678 KQ_UNLOCK(kq);
1679 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
1680 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1681 knl = kn_list_lock(kn);
1682 if (kn->kn_fop->f_event(kn, 0) == 0) {
1683 KQ_LOCK(kq);
1684 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1685 kn->kn_status &=
1686 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX |
1687 KN_SCAN);
1688 kq->kq_count--;
1689 kn_list_unlock(knl);
1690 influx = 1;
1691 continue;
1692 }
1693 touch = (!kn->kn_fop->f_isfd &&
1694 kn->kn_fop->f_touch != NULL);
1695 if (touch)
1696 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS);
1697 else
1698 *kevp = kn->kn_kevent;
1699 KQ_LOCK(kq);
1700 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1701 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
1702 /*
1703 * Manually clear knotes who weren't
1704 * 'touch'ed.
1705 */
1706 if (touch == 0 && kn->kn_flags & EV_CLEAR) {
1707 kn->kn_data = 0;
1708 kn->kn_fflags = 0;
1709 }
1710 if (kn->kn_flags & EV_DISPATCH)
1711 kn->kn_status |= KN_DISABLED;
1712 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
1713 kq->kq_count--;
1714 } else
1715 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
1716
1717 kn->kn_status &= ~(KN_INFLUX | KN_SCAN);
1718 kn_list_unlock(knl);
1719 influx = 1;
1720 }
1721
1722 /* we are returning a copy to the user */
1723 kevp++;
1724 nkev++;
1725 count--;
1726
1727 if (nkev == KQ_NEVENTS) {
1728 influx = 0;
1729 KQ_UNLOCK_FLUX(kq);
1730 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1731 nkev = 0;
1732 kevp = keva;
1733 KQ_LOCK(kq);
1734 if (error)
1735 break;
1736 }
1737 }
1738 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
1739 done:
1740 KQ_OWNED(kq);
1741 KQ_UNLOCK_FLUX(kq);
1742 knote_free(marker);
1743 done_nl:
1744 KQ_NOTOWNED(kq);
1745 if (nkev != 0)
1746 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
1747 td->td_retval[0] = maxevents - count;
1748 return (error);
1749 }
1750
1751 /*ARGSUSED*/
1752 static int
1753 kqueue_ioctl(struct file *fp, u_long cmd, void *data,
1754 struct ucred *active_cred, struct thread *td)
1755 {
1756 /*
1757 * Enabling sigio causes two major problems:
1758 * 1) infinite recursion:
1759 * Synopsys: kevent is being used to track signals and have FIOASYNC
1760 * set. On receipt of a signal this will cause a kqueue to recurse
1761 * into itself over and over. Sending the sigio causes the kqueue
1762 * to become ready, which in turn posts sigio again, forever.
1763 * Solution: this can be solved by setting a flag in the kqueue that
1764 * we have a SIGIO in progress.
1765 * 2) locking problems:
1766 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
1767 * us above the proc and pgrp locks.
1768 * Solution: Post a signal using an async mechanism, being sure to
1769 * record a generation count in the delivery so that we do not deliver
1770 * a signal to the wrong process.
1771 *
1772 * Note, these two mechanisms are somewhat mutually exclusive!
1773 */
1774 #if 0
1775 struct kqueue *kq;
1776
1777 kq = fp->f_data;
1778 switch (cmd) {
1779 case FIOASYNC:
1780 if (*(int *)data) {
1781 kq->kq_state |= KQ_ASYNC;
1782 } else {
1783 kq->kq_state &= ~KQ_ASYNC;
1784 }
1785 return (0);
1786
1787 case FIOSETOWN:
1788 return (fsetown(*(int *)data, &kq->kq_sigio));
1789
1790 case FIOGETOWN:
1791 *(int *)data = fgetown(&kq->kq_sigio);
1792 return (0);
1793 }
1794 #endif
1795
1796 return (ENOTTY);
1797 }
1798
1799 /*ARGSUSED*/
1800 static int
1801 kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
1802 struct thread *td)
1803 {
1804 struct kqueue *kq;
1805 int revents = 0;
1806 int error;
1807
1808 if ((error = kqueue_acquire(fp, &kq)))
1809 return POLLERR;
1810
1811 KQ_LOCK(kq);
1812 if (events & (POLLIN | POLLRDNORM)) {
1813 if (kq->kq_count) {
1814 revents |= events & (POLLIN | POLLRDNORM);
1815 } else {
1816 selrecord(td, &kq->kq_sel);
1817 if (SEL_WAITING(&kq->kq_sel))
1818 kq->kq_state |= KQ_SEL;
1819 }
1820 }
1821 kqueue_release(kq, 1);
1822 KQ_UNLOCK(kq);
1823 return (revents);
1824 }
1825
1826 /*ARGSUSED*/
1827 static int
1828 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
1829 struct thread *td)
1830 {
1831
1832 bzero((void *)st, sizeof *st);
1833 /*
1834 * We no longer return kq_count because the unlocked value is useless.
1835 * If you spent all this time getting the count, why not spend your
1836 * syscall better by calling kevent?
1837 *
1838 * XXX - This is needed for libc_r.
1839 */
1840 st->st_mode = S_IFIFO;
1841 return (0);
1842 }
1843
1844 static void
1845 kqueue_drain(struct kqueue *kq, struct thread *td)
1846 {
1847 struct knote *kn;
1848 int i;
1849
1850 KQ_LOCK(kq);
1851
1852 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
1853 ("kqueue already closing"));
1854 kq->kq_state |= KQ_CLOSING;
1855 if (kq->kq_refcnt > 1)
1856 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
1857
1858 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
1859
1860 KASSERT(knlist_empty(&kq->kq_sel.si_note),
1861 ("kqueue's knlist not empty"));
1862
1863 for (i = 0; i < kq->kq_knlistsize; i++) {
1864 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
1865 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1866 kq->kq_state |= KQ_FLUXWAIT;
1867 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
1868 continue;
1869 }
1870 kn->kn_status |= KN_INFLUX;
1871 KQ_UNLOCK(kq);
1872 if (!(kn->kn_status & KN_DETACHED))
1873 kn->kn_fop->f_detach(kn);
1874 knote_drop(kn, td);
1875 KQ_LOCK(kq);
1876 }
1877 }
1878 if (kq->kq_knhashmask != 0) {
1879 for (i = 0; i <= kq->kq_knhashmask; i++) {
1880 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
1881 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
1882 kq->kq_state |= KQ_FLUXWAIT;
1883 msleep(kq, &kq->kq_lock, PSOCK,
1884 "kqclo2", 0);
1885 continue;
1886 }
1887 kn->kn_status |= KN_INFLUX;
1888 KQ_UNLOCK(kq);
1889 if (!(kn->kn_status & KN_DETACHED))
1890 kn->kn_fop->f_detach(kn);
1891 knote_drop(kn, td);
1892 KQ_LOCK(kq);
1893 }
1894 }
1895 }
1896
1897 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
1898 kq->kq_state |= KQ_TASKDRAIN;
1899 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
1900 }
1901
1902 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
1903 selwakeuppri(&kq->kq_sel, PSOCK);
1904 if (!SEL_WAITING(&kq->kq_sel))
1905 kq->kq_state &= ~KQ_SEL;
1906 }
1907
1908 KQ_UNLOCK(kq);
1909 }
1910
1911 static void
1912 kqueue_destroy(struct kqueue *kq)
1913 {
1914
1915 KASSERT(kq->kq_fdp == NULL,
1916 ("kqueue still attached to a file descriptor"));
1917 seldrain(&kq->kq_sel);
1918 knlist_destroy(&kq->kq_sel.si_note);
1919 mtx_destroy(&kq->kq_lock);
1920
1921 if (kq->kq_knhash != NULL)
1922 free(kq->kq_knhash, M_KQUEUE);
1923 if (kq->kq_knlist != NULL)
1924 free(kq->kq_knlist, M_KQUEUE);
1925
1926 funsetown(&kq->kq_sigio);
1927 }
1928
1929 /*ARGSUSED*/
1930 static int
1931 kqueue_close(struct file *fp, struct thread *td)
1932 {
1933 struct kqueue *kq = fp->f_data;
1934 struct filedesc *fdp;
1935 int error;
1936 int filedesc_unlock;
1937
1938 if ((error = kqueue_acquire(fp, &kq)))
1939 return error;
1940 kqueue_drain(kq, td);
1941
1942 /*
1943 * We could be called due to the knote_drop() doing fdrop(),
1944 * called from kqueue_register(). In this case the global
1945 * lock is owned, and filedesc sx is locked before, to not
1946 * take the sleepable lock after non-sleepable.
1947 */
1948 fdp = kq->kq_fdp;
1949 kq->kq_fdp = NULL;
1950 if (!sx_xlocked(FILEDESC_LOCK(fdp))) {
1951 FILEDESC_XLOCK(fdp);
1952 filedesc_unlock = 1;
1953 } else
1954 filedesc_unlock = 0;
1955 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list);
1956 if (filedesc_unlock)
1957 FILEDESC_XUNLOCK(fdp);
1958
1959 kqueue_destroy(kq);
1960 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0);
1961 crfree(kq->kq_cred);
1962 free(kq, M_KQUEUE);
1963 fp->f_data = NULL;
1964
1965 return (0);
1966 }
1967
1968 static int
1969 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
1970 {
1971
1972 kif->kf_type = KF_TYPE_KQUEUE;
1973 return (0);
1974 }
1975
1976 static void
1977 kqueue_wakeup(struct kqueue *kq)
1978 {
1979 KQ_OWNED(kq);
1980
1981 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
1982 kq->kq_state &= ~KQ_SLEEP;
1983 wakeup(kq);
1984 }
1985 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
1986 selwakeuppri(&kq->kq_sel, PSOCK);
1987 if (!SEL_WAITING(&kq->kq_sel))
1988 kq->kq_state &= ~KQ_SEL;
1989 }
1990 if (!knlist_empty(&kq->kq_sel.si_note))
1991 kqueue_schedtask(kq);
1992 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
1993 pgsigio(&kq->kq_sigio, SIGIO, 0);
1994 }
1995 }
1996
1997 /*
1998 * Walk down a list of knotes, activating them if their event has triggered.
1999 *
2000 * There is a possibility to optimize in the case of one kq watching another.
2001 * Instead of scheduling a task to wake it up, you could pass enough state
2002 * down the chain to make up the parent kqueue. Make this code functional
2003 * first.
2004 */
2005 void
2006 knote(struct knlist *list, long hint, int lockflags)
2007 {
2008 struct kqueue *kq;
2009 struct knote *kn, *tkn;
2010 int error;
2011
2012 if (list == NULL)
2013 return;
2014
2015 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
2016
2017 if ((lockflags & KNF_LISTLOCKED) == 0)
2018 list->kl_lock(list->kl_lockarg);
2019
2020 /*
2021 * If we unlock the list lock (and set KN_INFLUX), we can
2022 * eliminate the kqueue scheduling, but this will introduce
2023 * four lock/unlock's for each knote to test. Also, marker
2024 * would be needed to keep iteration position, since filters
2025 * or other threads could remove events.
2026 */
2027 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) {
2028 kq = kn->kn_kq;
2029 KQ_LOCK(kq);
2030 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) {
2031 /*
2032 * Do not process the influx notes, except for
2033 * the influx coming from the kq unlock in the
2034 * kqueue_scan(). In the later case, we do
2035 * not interfere with the scan, since the code
2036 * fragment in kqueue_scan() locks the knlist,
2037 * and cannot proceed until we finished.
2038 */
2039 KQ_UNLOCK(kq);
2040 } else if ((lockflags & KNF_NOKQLOCK) != 0) {
2041 kn->kn_status |= KN_INFLUX;
2042 KQ_UNLOCK(kq);
2043 error = kn->kn_fop->f_event(kn, hint);
2044 KQ_LOCK(kq);
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 #ifdef INVARIANTS
2247 /*
2248 * if we run across this error, we need to find the offending
2249 * driver and have it call knlist_clear or knlist_delete.
2250 */
2251 if (!SLIST_EMPTY(&knl->kl_list))
2252 printf("WARNING: destroying knlist w/ knotes on it!\n");
2253 #endif
2254
2255 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL;
2256 SLIST_INIT(&knl->kl_list);
2257 }
2258
2259 void
2260 knlist_detach(struct knlist *knl)
2261 {
2262
2263 KNL_ASSERT_LOCKED(knl);
2264 knl->kl_autodestroy = 1;
2265 if (knlist_empty(knl)) {
2266 knlist_destroy(knl);
2267 free(knl, M_KQUEUE);
2268 }
2269 }
2270
2271 /*
2272 * Even if we are locked, we may need to drop the lock to allow any influx
2273 * knotes time to "settle".
2274 */
2275 void
2276 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
2277 {
2278 struct knote *kn, *kn2;
2279 struct kqueue *kq;
2280
2281 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl));
2282 if (islocked)
2283 KNL_ASSERT_LOCKED(knl);
2284 else {
2285 KNL_ASSERT_UNLOCKED(knl);
2286 again: /* need to reacquire lock since we have dropped it */
2287 knl->kl_lock(knl->kl_lockarg);
2288 }
2289
2290 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
2291 kq = kn->kn_kq;
2292 KQ_LOCK(kq);
2293 if ((kn->kn_status & KN_INFLUX)) {
2294 KQ_UNLOCK(kq);
2295 continue;
2296 }
2297 knlist_remove_kq(knl, kn, 1, 1);
2298 if (killkn) {
2299 kn->kn_status |= KN_INFLUX | KN_DETACHED;
2300 KQ_UNLOCK(kq);
2301 knote_drop(kn, td);
2302 } else {
2303 /* Make sure cleared knotes disappear soon */
2304 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
2305 KQ_UNLOCK(kq);
2306 }
2307 kq = NULL;
2308 }
2309
2310 if (!SLIST_EMPTY(&knl->kl_list)) {
2311 /* there are still KN_INFLUX remaining */
2312 kn = SLIST_FIRST(&knl->kl_list);
2313 kq = kn->kn_kq;
2314 KQ_LOCK(kq);
2315 KASSERT(kn->kn_status & KN_INFLUX,
2316 ("knote removed w/o list lock"));
2317 knl->kl_unlock(knl->kl_lockarg);
2318 kq->kq_state |= KQ_FLUXWAIT;
2319 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
2320 kq = NULL;
2321 goto again;
2322 }
2323
2324 if (islocked)
2325 KNL_ASSERT_LOCKED(knl);
2326 else {
2327 knl->kl_unlock(knl->kl_lockarg);
2328 KNL_ASSERT_UNLOCKED(knl);
2329 }
2330 }
2331
2332 /*
2333 * Remove all knotes referencing a specified fd must be called with FILEDESC
2334 * lock. This prevents a race where a new fd comes along and occupies the
2335 * entry and we attach a knote to the fd.
2336 */
2337 void
2338 knote_fdclose(struct thread *td, int fd)
2339 {
2340 struct filedesc *fdp = td->td_proc->p_fd;
2341 struct kqueue *kq;
2342 struct knote *kn;
2343 int influx;
2344
2345 FILEDESC_XLOCK_ASSERT(fdp);
2346
2347 /*
2348 * We shouldn't have to worry about new kevents appearing on fd
2349 * since filedesc is locked.
2350 */
2351 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
2352 KQ_LOCK(kq);
2353
2354 again:
2355 influx = 0;
2356 while (kq->kq_knlistsize > fd &&
2357 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
2358 if (kn->kn_status & KN_INFLUX) {
2359 /* someone else might be waiting on our knote */
2360 if (influx)
2361 wakeup(kq);
2362 kq->kq_state |= KQ_FLUXWAIT;
2363 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
2364 goto again;
2365 }
2366 kn->kn_status |= KN_INFLUX;
2367 KQ_UNLOCK(kq);
2368 if (!(kn->kn_status & KN_DETACHED))
2369 kn->kn_fop->f_detach(kn);
2370 knote_drop(kn, td);
2371 influx = 1;
2372 KQ_LOCK(kq);
2373 }
2374 KQ_UNLOCK_FLUX(kq);
2375 }
2376 }
2377
2378 static int
2379 knote_attach(struct knote *kn, struct kqueue *kq)
2380 {
2381 struct klist *list;
2382
2383 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX"));
2384 KQ_OWNED(kq);
2385
2386 if (kn->kn_fop->f_isfd) {
2387 if (kn->kn_id >= kq->kq_knlistsize)
2388 return ENOMEM;
2389 list = &kq->kq_knlist[kn->kn_id];
2390 } else {
2391 if (kq->kq_knhash == NULL)
2392 return ENOMEM;
2393 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2394 }
2395
2396 SLIST_INSERT_HEAD(list, kn, kn_link);
2397
2398 return 0;
2399 }
2400
2401 /*
2402 * knote must already have been detached using the f_detach method.
2403 * no lock need to be held, it is assumed that the KN_INFLUX flag is set
2404 * to prevent other removal.
2405 */
2406 static void
2407 knote_drop(struct knote *kn, struct thread *td)
2408 {
2409 struct kqueue *kq;
2410 struct klist *list;
2411
2412 kq = kn->kn_kq;
2413
2414 KQ_NOTOWNED(kq);
2415 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX,
2416 ("knote_drop called without KN_INFLUX set in kn_status"));
2417
2418 KQ_LOCK(kq);
2419 if (kn->kn_fop->f_isfd)
2420 list = &kq->kq_knlist[kn->kn_id];
2421 else
2422 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2423
2424 if (!SLIST_EMPTY(list))
2425 SLIST_REMOVE(list, kn, knote, kn_link);
2426 if (kn->kn_status & KN_QUEUED)
2427 knote_dequeue(kn);
2428 KQ_UNLOCK_FLUX(kq);
2429
2430 if (kn->kn_fop->f_isfd) {
2431 fdrop(kn->kn_fp, td);
2432 kn->kn_fp = NULL;
2433 }
2434 kqueue_fo_release(kn->kn_kevent.filter);
2435 kn->kn_fop = NULL;
2436 knote_free(kn);
2437 }
2438
2439 static void
2440 knote_enqueue(struct knote *kn)
2441 {
2442 struct kqueue *kq = kn->kn_kq;
2443
2444 KQ_OWNED(kn->kn_kq);
2445 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
2446
2447 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
2448 kn->kn_status |= KN_QUEUED;
2449 kq->kq_count++;
2450 kqueue_wakeup(kq);
2451 }
2452
2453 static void
2454 knote_dequeue(struct knote *kn)
2455 {
2456 struct kqueue *kq = kn->kn_kq;
2457
2458 KQ_OWNED(kn->kn_kq);
2459 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
2460
2461 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
2462 kn->kn_status &= ~KN_QUEUED;
2463 kq->kq_count--;
2464 }
2465
2466 static void
2467 knote_init(void)
2468 {
2469
2470 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
2471 NULL, NULL, UMA_ALIGN_PTR, 0);
2472 }
2473 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
2474
2475 static struct knote *
2476 knote_alloc(int waitok)
2477 {
2478
2479 return (uma_zalloc(knote_zone, (waitok ? M_WAITOK : M_NOWAIT) |
2480 M_ZERO));
2481 }
2482
2483 static void
2484 knote_free(struct knote *kn)
2485 {
2486
2487 uma_zfree(knote_zone, kn);
2488 }
2489
2490 /*
2491 * Register the kev w/ the kq specified by fd.
2492 */
2493 int
2494 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok)
2495 {
2496 struct kqueue *kq;
2497 struct file *fp;
2498 cap_rights_t rights;
2499 int error;
2500
2501 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp);
2502 if (error != 0)
2503 return (error);
2504 if ((error = kqueue_acquire(fp, &kq)) != 0)
2505 goto noacquire;
2506
2507 error = kqueue_register(kq, kev, td, waitok);
2508
2509 kqueue_release(kq, 0);
2510
2511 noacquire:
2512 fdrop(fp, td);
2513
2514 return error;
2515 }
Cache object: 2d6cba00eb22f14cb82121ae38bb4746
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