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 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD: src/sys/kern/kern_event.c,v 1.122 2008/07/07 09:30:11 kib Exp $");
30
31 #include "opt_ktrace.h"
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/kernel.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/proc.h>
39 #include <sys/malloc.h>
40 #include <sys/unistd.h>
41 #include <sys/file.h>
42 #include <sys/filedesc.h>
43 #include <sys/filio.h>
44 #include <sys/fcntl.h>
45 #include <sys/kthread.h>
46 #include <sys/selinfo.h>
47 #include <sys/queue.h>
48 #include <sys/event.h>
49 #include <sys/eventvar.h>
50 #include <sys/poll.h>
51 #include <sys/protosw.h>
52 #include <sys/sigio.h>
53 #include <sys/signalvar.h>
54 #include <sys/socket.h>
55 #include <sys/socketvar.h>
56 #include <sys/stat.h>
57 #include <sys/sysctl.h>
58 #include <sys/sysproto.h>
59 #include <sys/syscallsubr.h>
60 #include <sys/taskqueue.h>
61 #include <sys/uio.h>
62 #ifdef KTRACE
63 #include <sys/ktrace.h>
64 #endif
65
66 #include <vm/uma.h>
67
68 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
69
70 /*
71 * This lock is used if multiple kq locks are required. This possibly
72 * should be made into a per proc lock.
73 */
74 static struct mtx kq_global;
75 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF);
76 #define KQ_GLOBAL_LOCK(lck, haslck) do { \
77 if (!haslck) \
78 mtx_lock(lck); \
79 haslck = 1; \
80 } while (0)
81 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \
82 if (haslck) \
83 mtx_unlock(lck); \
84 haslck = 0; \
85 } while (0)
86
87 TASKQUEUE_DEFINE_THREAD(kqueue);
88
89 static int kevent_copyout(void *arg, struct kevent *kevp, int count);
90 static int kevent_copyin(void *arg, struct kevent *kevp, int count);
91 static int kqueue_register(struct kqueue *kq, struct kevent *kev,
92 struct thread *td, int waitok);
93 static int kqueue_acquire(struct file *fp, struct kqueue **kqp);
94 static void kqueue_release(struct kqueue *kq, int locked);
95 static int kqueue_expand(struct kqueue *kq, struct filterops *fops,
96 uintptr_t ident, int waitok);
97 static void kqueue_task(void *arg, int pending);
98 static int kqueue_scan(struct kqueue *kq, int maxevents,
99 struct kevent_copyops *k_ops,
100 const struct timespec *timeout,
101 struct kevent *keva, struct thread *td);
102 static void kqueue_wakeup(struct kqueue *kq);
103 static struct filterops *kqueue_fo_find(int filt);
104 static void kqueue_fo_release(int filt);
105
106 static fo_rdwr_t kqueue_read;
107 static fo_rdwr_t kqueue_write;
108 static fo_truncate_t kqueue_truncate;
109 static fo_ioctl_t kqueue_ioctl;
110 static fo_poll_t kqueue_poll;
111 static fo_kqfilter_t kqueue_kqfilter;
112 static fo_stat_t kqueue_stat;
113 static fo_close_t kqueue_close;
114
115 static struct fileops kqueueops = {
116 .fo_read = kqueue_read,
117 .fo_write = kqueue_write,
118 .fo_truncate = kqueue_truncate,
119 .fo_ioctl = kqueue_ioctl,
120 .fo_poll = kqueue_poll,
121 .fo_kqfilter = kqueue_kqfilter,
122 .fo_stat = kqueue_stat,
123 .fo_close = kqueue_close,
124 };
125
126 static int knote_attach(struct knote *kn, struct kqueue *kq);
127 static void knote_drop(struct knote *kn, struct thread *td);
128 static void knote_enqueue(struct knote *kn);
129 static void knote_dequeue(struct knote *kn);
130 static void knote_init(void);
131 static struct knote *knote_alloc(int waitok);
132 static void knote_free(struct knote *kn);
133
134 static void filt_kqdetach(struct knote *kn);
135 static int filt_kqueue(struct knote *kn, long hint);
136 static int filt_procattach(struct knote *kn);
137 static void filt_procdetach(struct knote *kn);
138 static int filt_proc(struct knote *kn, long hint);
139 static int filt_fileattach(struct knote *kn);
140 static void filt_timerexpire(void *knx);
141 static int filt_timerattach(struct knote *kn);
142 static void filt_timerdetach(struct knote *kn);
143 static int filt_timer(struct knote *kn, long hint);
144
145 static struct filterops file_filtops =
146 { 1, filt_fileattach, NULL, NULL };
147 static struct filterops kqread_filtops =
148 { 1, NULL, filt_kqdetach, filt_kqueue };
149 /* XXX - move to kern_proc.c? */
150 static struct filterops proc_filtops =
151 { 0, filt_procattach, filt_procdetach, filt_proc };
152 static struct filterops timer_filtops =
153 { 0, filt_timerattach, filt_timerdetach, filt_timer };
154
155 static uma_zone_t knote_zone;
156 static int kq_ncallouts = 0;
157 static int kq_calloutmax = (4 * 1024);
158 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
159 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
160
161 /* XXX - ensure not KN_INFLUX?? */
162 #define KNOTE_ACTIVATE(kn, islock) do { \
163 if ((islock)) \
164 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \
165 else \
166 KQ_LOCK((kn)->kn_kq); \
167 (kn)->kn_status |= KN_ACTIVE; \
168 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
169 knote_enqueue((kn)); \
170 if (!(islock)) \
171 KQ_UNLOCK((kn)->kn_kq); \
172 } while(0)
173 #define KQ_LOCK(kq) do { \
174 mtx_lock(&(kq)->kq_lock); \
175 } while (0)
176 #define KQ_FLUX_WAKEUP(kq) do { \
177 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \
178 (kq)->kq_state &= ~KQ_FLUXWAIT; \
179 wakeup((kq)); \
180 } \
181 } while (0)
182 #define KQ_UNLOCK_FLUX(kq) do { \
183 KQ_FLUX_WAKEUP(kq); \
184 mtx_unlock(&(kq)->kq_lock); \
185 } while (0)
186 #define KQ_UNLOCK(kq) do { \
187 mtx_unlock(&(kq)->kq_lock); \
188 } while (0)
189 #define KQ_OWNED(kq) do { \
190 mtx_assert(&(kq)->kq_lock, MA_OWNED); \
191 } while (0)
192 #define KQ_NOTOWNED(kq) do { \
193 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \
194 } while (0)
195 #define KN_LIST_LOCK(kn) do { \
196 if (kn->kn_knlist != NULL) \
197 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \
198 } while (0)
199 #define KN_LIST_UNLOCK(kn) do { \
200 if (kn->kn_knlist != NULL) \
201 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \
202 } while (0)
203 #define KNL_ASSERT_LOCK(knl, islocked) do { \
204 if (islocked) \
205 KNL_ASSERT_LOCKED(knl); \
206 else \
207 KNL_ASSERT_UNLOCKED(knl); \
208 } while (0)
209 #ifdef INVARIANTS
210 #define KNL_ASSERT_LOCKED(knl) do { \
211 if (!knl->kl_locked((knl)->kl_lockarg)) \
212 panic("knlist not locked, but should be"); \
213 } while (0)
214 #define KNL_ASSERT_UNLOCKED(knl) do { \
215 if (knl->kl_locked((knl)->kl_lockarg)) \
216 panic("knlist locked, but should not be"); \
217 } while (0)
218 #else /* !INVARIANTS */
219 #define KNL_ASSERT_LOCKED(knl) do {} while(0)
220 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
221 #endif /* INVARIANTS */
222
223 #define KN_HASHSIZE 64 /* XXX should be tunable */
224 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
225
226 static int
227 filt_nullattach(struct knote *kn)
228 {
229
230 return (ENXIO);
231 };
232
233 struct filterops null_filtops =
234 { 0, filt_nullattach, NULL, NULL };
235
236 /* XXX - make SYSINIT to add these, and move into respective modules. */
237 extern struct filterops sig_filtops;
238 extern struct filterops fs_filtops;
239
240 /*
241 * Table for for all system-defined filters.
242 */
243 static struct mtx filterops_lock;
244 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops",
245 MTX_DEF);
246 static struct {
247 struct filterops *for_fop;
248 int for_refcnt;
249 } sysfilt_ops[EVFILT_SYSCOUNT] = {
250 { &file_filtops }, /* EVFILT_READ */
251 { &file_filtops }, /* EVFILT_WRITE */
252 { &null_filtops }, /* EVFILT_AIO */
253 { &file_filtops }, /* EVFILT_VNODE */
254 { &proc_filtops }, /* EVFILT_PROC */
255 { &sig_filtops }, /* EVFILT_SIGNAL */
256 { &timer_filtops }, /* EVFILT_TIMER */
257 { &file_filtops }, /* EVFILT_NETDEV */
258 { &fs_filtops }, /* EVFILT_FS */
259 { &null_filtops }, /* EVFILT_LIO */
260 };
261
262 /*
263 * Simple redirection for all cdevsw style objects to call their fo_kqfilter
264 * method.
265 */
266 static int
267 filt_fileattach(struct knote *kn)
268 {
269
270 return (fo_kqfilter(kn->kn_fp, kn));
271 }
272
273 /*ARGSUSED*/
274 static int
275 kqueue_kqfilter(struct file *fp, struct knote *kn)
276 {
277 struct kqueue *kq = kn->kn_fp->f_data;
278
279 if (kn->kn_filter != EVFILT_READ)
280 return (EINVAL);
281
282 kn->kn_status |= KN_KQUEUE;
283 kn->kn_fop = &kqread_filtops;
284 knlist_add(&kq->kq_sel.si_note, kn, 0);
285
286 return (0);
287 }
288
289 static void
290 filt_kqdetach(struct knote *kn)
291 {
292 struct kqueue *kq = kn->kn_fp->f_data;
293
294 knlist_remove(&kq->kq_sel.si_note, kn, 0);
295 }
296
297 /*ARGSUSED*/
298 static int
299 filt_kqueue(struct knote *kn, long hint)
300 {
301 struct kqueue *kq = kn->kn_fp->f_data;
302
303 kn->kn_data = kq->kq_count;
304 return (kn->kn_data > 0);
305 }
306
307 /* XXX - move to kern_proc.c? */
308 static int
309 filt_procattach(struct knote *kn)
310 {
311 struct proc *p;
312 int immediate;
313 int error;
314
315 immediate = 0;
316 p = pfind(kn->kn_id);
317 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
318 p = zpfind(kn->kn_id);
319 immediate = 1;
320 } else if (p != NULL && (p->p_flag & P_WEXIT)) {
321 immediate = 1;
322 }
323
324 if (p == NULL)
325 return (ESRCH);
326 if ((error = p_cansee(curthread, p)))
327 return (error);
328
329 kn->kn_ptr.p_proc = p;
330 kn->kn_flags |= EV_CLEAR; /* automatically set */
331
332 /*
333 * internal flag indicating registration done by kernel
334 */
335 if (kn->kn_flags & EV_FLAG1) {
336 kn->kn_data = kn->kn_sdata; /* ppid */
337 kn->kn_fflags = NOTE_CHILD;
338 kn->kn_flags &= ~EV_FLAG1;
339 }
340
341 if (immediate == 0)
342 knlist_add(&p->p_klist, kn, 1);
343
344 /*
345 * Immediately activate any exit notes if the target process is a
346 * zombie. This is necessary to handle the case where the target
347 * process, e.g. a child, dies before the kevent is registered.
348 */
349 if (immediate && filt_proc(kn, NOTE_EXIT))
350 KNOTE_ACTIVATE(kn, 0);
351
352 PROC_UNLOCK(p);
353
354 return (0);
355 }
356
357 /*
358 * The knote may be attached to a different process, which may exit,
359 * leaving nothing for the knote to be attached to. So when the process
360 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
361 * it will be deleted when read out. However, as part of the knote deletion,
362 * this routine is called, so a check is needed to avoid actually performing
363 * a detach, because the original process does not exist any more.
364 */
365 /* XXX - move to kern_proc.c? */
366 static void
367 filt_procdetach(struct knote *kn)
368 {
369 struct proc *p;
370
371 p = kn->kn_ptr.p_proc;
372 knlist_remove(&p->p_klist, kn, 0);
373 kn->kn_ptr.p_proc = NULL;
374 }
375
376 /* XXX - move to kern_proc.c? */
377 static int
378 filt_proc(struct knote *kn, long hint)
379 {
380 struct proc *p = kn->kn_ptr.p_proc;
381 u_int event;
382
383 /*
384 * mask off extra data
385 */
386 event = (u_int)hint & NOTE_PCTRLMASK;
387
388 /*
389 * if the user is interested in this event, record it.
390 */
391 if (kn->kn_sfflags & event)
392 kn->kn_fflags |= event;
393
394 /*
395 * process is gone, so flag the event as finished.
396 */
397 if (event == NOTE_EXIT) {
398 if (!(kn->kn_status & KN_DETACHED))
399 knlist_remove_inevent(&p->p_klist, kn);
400 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
401 kn->kn_data = p->p_xstat;
402 kn->kn_ptr.p_proc = NULL;
403 return (1);
404 }
405
406 return (kn->kn_fflags != 0);
407 }
408
409 /*
410 * Called when the process forked. It mostly does the same as the
411 * knote(), activating all knotes registered to be activated when the
412 * process forked. Additionally, for each knote attached to the
413 * parent, check whether user wants to track the new process. If so
414 * attach a new knote to it, and immediately report an event with the
415 * child's pid.
416 */
417 void
418 knote_fork(struct knlist *list, int pid)
419 {
420 struct kqueue *kq;
421 struct knote *kn;
422 struct kevent kev;
423 int error;
424
425 if (list == NULL)
426 return;
427 list->kl_lock(list->kl_lockarg);
428
429 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
430 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX)
431 continue;
432 kq = kn->kn_kq;
433 KQ_LOCK(kq);
434 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
435 KQ_UNLOCK(kq);
436 continue;
437 }
438
439 /*
440 * The same as knote(), activate the event.
441 */
442 if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
443 kn->kn_status |= KN_HASKQLOCK;
444 if (kn->kn_fop->f_event(kn, NOTE_FORK | pid))
445 KNOTE_ACTIVATE(kn, 1);
446 kn->kn_status &= ~KN_HASKQLOCK;
447 KQ_UNLOCK(kq);
448 continue;
449 }
450
451 /*
452 * The NOTE_TRACK case. In addition to the activation
453 * of the event, we need to register new event to
454 * track the child. Drop the locks in preparation for
455 * the call to kqueue_register().
456 */
457 kn->kn_status |= KN_INFLUX;
458 KQ_UNLOCK(kq);
459 list->kl_unlock(list->kl_lockarg);
460
461 /*
462 * Activate existing knote and register a knote with
463 * new process.
464 */
465 kev.ident = pid;
466 kev.filter = kn->kn_filter;
467 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
468 kev.fflags = kn->kn_sfflags;
469 kev.data = kn->kn_id; /* parent */
470 kev.udata = kn->kn_kevent.udata;/* preserve udata */
471 error = kqueue_register(kq, &kev, NULL, 0);
472 if (kn->kn_fop->f_event(kn, NOTE_FORK | pid))
473 KNOTE_ACTIVATE(kn, 0);
474 if (error)
475 kn->kn_fflags |= NOTE_TRACKERR;
476 KQ_LOCK(kq);
477 kn->kn_status &= ~KN_INFLUX;
478 KQ_UNLOCK_FLUX(kq);
479 list->kl_lock(list->kl_lockarg);
480 }
481 list->kl_unlock(list->kl_lockarg);
482 }
483
484 static int
485 timertoticks(intptr_t data)
486 {
487 struct timeval tv;
488 int tticks;
489
490 tv.tv_sec = data / 1000;
491 tv.tv_usec = (data % 1000) * 1000;
492 tticks = tvtohz(&tv);
493
494 return tticks;
495 }
496
497 /* XXX - move to kern_timeout.c? */
498 static void
499 filt_timerexpire(void *knx)
500 {
501 struct knote *kn = knx;
502 struct callout *calloutp;
503
504 kn->kn_data++;
505 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
506
507 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) {
508 calloutp = (struct callout *)kn->kn_hook;
509 callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata),
510 filt_timerexpire, kn);
511 }
512 }
513
514 /*
515 * data contains amount of time to sleep, in milliseconds
516 */
517 /* XXX - move to kern_timeout.c? */
518 static int
519 filt_timerattach(struct knote *kn)
520 {
521 struct callout *calloutp;
522
523 atomic_add_int(&kq_ncallouts, 1);
524
525 if (kq_ncallouts >= kq_calloutmax) {
526 atomic_add_int(&kq_ncallouts, -1);
527 return (ENOMEM);
528 }
529
530 kn->kn_flags |= EV_CLEAR; /* automatically set */
531 kn->kn_status &= ~KN_DETACHED; /* knlist_add usually sets it */
532 MALLOC(calloutp, struct callout *, sizeof(*calloutp),
533 M_KQUEUE, M_WAITOK);
534 callout_init(calloutp, CALLOUT_MPSAFE);
535 kn->kn_hook = calloutp;
536 callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata),
537 filt_timerexpire, kn);
538
539 return (0);
540 }
541
542 /* XXX - move to kern_timeout.c? */
543 static void
544 filt_timerdetach(struct knote *kn)
545 {
546 struct callout *calloutp;
547
548 calloutp = (struct callout *)kn->kn_hook;
549 callout_drain(calloutp);
550 FREE(calloutp, M_KQUEUE);
551 atomic_add_int(&kq_ncallouts, -1);
552 kn->kn_status |= KN_DETACHED; /* knlist_remove usually clears it */
553 }
554
555 /* XXX - move to kern_timeout.c? */
556 static int
557 filt_timer(struct knote *kn, long hint)
558 {
559
560 return (kn->kn_data != 0);
561 }
562
563 int
564 kqueue(struct thread *td, struct kqueue_args *uap)
565 {
566 struct filedesc *fdp;
567 struct kqueue *kq;
568 struct file *fp;
569 int fd, error;
570
571 fdp = td->td_proc->p_fd;
572 error = falloc(td, &fp, &fd);
573 if (error)
574 goto done2;
575
576 /* An extra reference on `nfp' has been held for us by falloc(). */
577 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
578 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK);
579 TAILQ_INIT(&kq->kq_head);
580 kq->kq_fdp = fdp;
581 knlist_init(&kq->kq_sel.si_note, &kq->kq_lock, NULL, NULL, NULL);
582 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
583
584 FILEDESC_XLOCK(fdp);
585 SLIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
586 FILEDESC_XUNLOCK(fdp);
587
588 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
589 fdrop(fp, td);
590
591 td->td_retval[0] = fd;
592 done2:
593 return (error);
594 }
595
596 #ifndef _SYS_SYSPROTO_H_
597 struct kevent_args {
598 int fd;
599 const struct kevent *changelist;
600 int nchanges;
601 struct kevent *eventlist;
602 int nevents;
603 const struct timespec *timeout;
604 };
605 #endif
606 int
607 kevent(struct thread *td, struct kevent_args *uap)
608 {
609 struct timespec ts, *tsp;
610 struct kevent_copyops k_ops = { uap,
611 kevent_copyout,
612 kevent_copyin};
613 int error;
614 #ifdef KTRACE
615 struct uio ktruio;
616 struct iovec ktriov;
617 struct uio *ktruioin = NULL;
618 struct uio *ktruioout = NULL;
619 #endif
620
621 if (uap->timeout != NULL) {
622 error = copyin(uap->timeout, &ts, sizeof(ts));
623 if (error)
624 return (error);
625 tsp = &ts;
626 } else
627 tsp = NULL;
628
629 #ifdef KTRACE
630 if (KTRPOINT(td, KTR_GENIO)) {
631 ktriov.iov_base = uap->changelist;
632 ktriov.iov_len = uap->nchanges * sizeof(struct kevent);
633 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1,
634 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ,
635 .uio_td = td };
636 ktruioin = cloneuio(&ktruio);
637 ktriov.iov_base = uap->eventlist;
638 ktriov.iov_len = uap->nevents * sizeof(struct kevent);
639 ktruioout = cloneuio(&ktruio);
640 }
641 #endif
642
643 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
644 &k_ops, tsp);
645
646 #ifdef KTRACE
647 if (ktruioin != NULL) {
648 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent);
649 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0);
650 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent);
651 ktrgenio(uap->fd, UIO_READ, ktruioout, error);
652 }
653 #endif
654
655 return (error);
656 }
657
658 /*
659 * Copy 'count' items into the destination list pointed to by uap->eventlist.
660 */
661 static int
662 kevent_copyout(void *arg, struct kevent *kevp, int count)
663 {
664 struct kevent_args *uap;
665 int error;
666
667 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
668 uap = (struct kevent_args *)arg;
669
670 error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
671 if (error == 0)
672 uap->eventlist += count;
673 return (error);
674 }
675
676 /*
677 * Copy 'count' items from the list pointed to by uap->changelist.
678 */
679 static int
680 kevent_copyin(void *arg, struct kevent *kevp, int count)
681 {
682 struct kevent_args *uap;
683 int error;
684
685 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
686 uap = (struct kevent_args *)arg;
687
688 error = copyin(uap->changelist, kevp, count * sizeof *kevp);
689 if (error == 0)
690 uap->changelist += count;
691 return (error);
692 }
693
694 int
695 kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
696 struct kevent_copyops *k_ops, const struct timespec *timeout)
697 {
698 struct kevent keva[KQ_NEVENTS];
699 struct kevent *kevp, *changes;
700 struct kqueue *kq;
701 struct file *fp;
702 int i, n, nerrors, error;
703
704 if ((error = fget(td, fd, &fp)) != 0)
705 return (error);
706 if ((error = kqueue_acquire(fp, &kq)) != 0)
707 goto done_norel;
708
709 nerrors = 0;
710
711 while (nchanges > 0) {
712 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
713 error = k_ops->k_copyin(k_ops->arg, keva, n);
714 if (error)
715 goto done;
716 changes = keva;
717 for (i = 0; i < n; i++) {
718 kevp = &changes[i];
719 if (!kevp->filter)
720 continue;
721 kevp->flags &= ~EV_SYSFLAGS;
722 error = kqueue_register(kq, kevp, td, 1);
723 if (error) {
724 if (nevents != 0) {
725 kevp->flags = EV_ERROR;
726 kevp->data = error;
727 (void) k_ops->k_copyout(k_ops->arg,
728 kevp, 1);
729 nevents--;
730 nerrors++;
731 } else {
732 goto done;
733 }
734 }
735 }
736 nchanges -= n;
737 }
738 if (nerrors) {
739 td->td_retval[0] = nerrors;
740 error = 0;
741 goto done;
742 }
743
744 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td);
745 done:
746 kqueue_release(kq, 0);
747 done_norel:
748 fdrop(fp, td);
749 return (error);
750 }
751
752 int
753 kqueue_add_filteropts(int filt, struct filterops *filtops)
754 {
755 int error;
756
757 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
758 printf(
759 "trying to add a filterop that is out of range: %d is beyond %d\n",
760 ~filt, EVFILT_SYSCOUNT);
761 return EINVAL;
762 }
763 mtx_lock(&filterops_lock);
764 if (sysfilt_ops[~filt].for_fop != &null_filtops &&
765 sysfilt_ops[~filt].for_fop != NULL)
766 error = EEXIST;
767 else {
768 sysfilt_ops[~filt].for_fop = filtops;
769 sysfilt_ops[~filt].for_refcnt = 0;
770 }
771 mtx_unlock(&filterops_lock);
772
773 return (0);
774 }
775
776 int
777 kqueue_del_filteropts(int filt)
778 {
779 int error;
780
781 error = 0;
782 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
783 return EINVAL;
784
785 mtx_lock(&filterops_lock);
786 if (sysfilt_ops[~filt].for_fop == &null_filtops ||
787 sysfilt_ops[~filt].for_fop == NULL)
788 error = EINVAL;
789 else if (sysfilt_ops[~filt].for_refcnt != 0)
790 error = EBUSY;
791 else {
792 sysfilt_ops[~filt].for_fop = &null_filtops;
793 sysfilt_ops[~filt].for_refcnt = 0;
794 }
795 mtx_unlock(&filterops_lock);
796
797 return error;
798 }
799
800 static struct filterops *
801 kqueue_fo_find(int filt)
802 {
803
804 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
805 return NULL;
806
807 mtx_lock(&filterops_lock);
808 sysfilt_ops[~filt].for_refcnt++;
809 if (sysfilt_ops[~filt].for_fop == NULL)
810 sysfilt_ops[~filt].for_fop = &null_filtops;
811 mtx_unlock(&filterops_lock);
812
813 return sysfilt_ops[~filt].for_fop;
814 }
815
816 static void
817 kqueue_fo_release(int filt)
818 {
819
820 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
821 return;
822
823 mtx_lock(&filterops_lock);
824 KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
825 ("filter object refcount not valid on release"));
826 sysfilt_ops[~filt].for_refcnt--;
827 mtx_unlock(&filterops_lock);
828 }
829
830 /*
831 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will
832 * influence if memory allocation should wait. Make sure it is 0 if you
833 * hold any mutexes.
834 */
835 static int
836 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok)
837 {
838 struct filterops *fops;
839 struct file *fp;
840 struct knote *kn, *tkn;
841 int error, filt, event;
842 int haskqglobal;
843
844 fp = NULL;
845 kn = NULL;
846 error = 0;
847 haskqglobal = 0;
848
849 filt = kev->filter;
850 fops = kqueue_fo_find(filt);
851 if (fops == NULL)
852 return EINVAL;
853
854 tkn = knote_alloc(waitok); /* prevent waiting with locks */
855
856 findkn:
857 if (fops->f_isfd) {
858 KASSERT(td != NULL, ("td is NULL"));
859 error = fget(td, kev->ident, &fp);
860 if (error)
861 goto done;
862
863 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
864 kev->ident, 0) != 0) {
865 /* try again */
866 fdrop(fp, td);
867 fp = NULL;
868 error = kqueue_expand(kq, fops, kev->ident, waitok);
869 if (error)
870 goto done;
871 goto findkn;
872 }
873
874 if (fp->f_type == DTYPE_KQUEUE) {
875 /*
876 * if we add some inteligence about what we are doing,
877 * we should be able to support events on ourselves.
878 * We need to know when we are doing this to prevent
879 * getting both the knlist lock and the kq lock since
880 * they are the same thing.
881 */
882 if (fp->f_data == kq) {
883 error = EINVAL;
884 goto done;
885 }
886
887 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
888 }
889
890 KQ_LOCK(kq);
891 if (kev->ident < kq->kq_knlistsize) {
892 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
893 if (kev->filter == kn->kn_filter)
894 break;
895 }
896 } else {
897 if ((kev->flags & EV_ADD) == EV_ADD)
898 kqueue_expand(kq, fops, kev->ident, waitok);
899
900 KQ_LOCK(kq);
901 if (kq->kq_knhashmask != 0) {
902 struct klist *list;
903
904 list = &kq->kq_knhash[
905 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
906 SLIST_FOREACH(kn, list, kn_link)
907 if (kev->ident == kn->kn_id &&
908 kev->filter == kn->kn_filter)
909 break;
910 }
911 }
912
913 /* knote is in the process of changing, wait for it to stablize. */
914 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
915 if (fp != NULL) {
916 fdrop(fp, td);
917 fp = NULL;
918 }
919 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
920 kq->kq_state |= KQ_FLUXWAIT;
921 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
922 goto findkn;
923 }
924
925 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
926 KQ_UNLOCK(kq);
927 error = ENOENT;
928 goto done;
929 }
930
931 /*
932 * kn now contains the matching knote, or NULL if no match
933 */
934 if (kev->flags & EV_ADD) {
935 if (kn == NULL) {
936 kn = tkn;
937 tkn = NULL;
938 if (kn == NULL) {
939 KQ_UNLOCK(kq);
940 error = ENOMEM;
941 goto done;
942 }
943 kn->kn_fp = fp;
944 kn->kn_kq = kq;
945 kn->kn_fop = fops;
946 /*
947 * apply reference counts to knote structure, and
948 * do not release it at the end of this routine.
949 */
950 fops = NULL;
951 fp = NULL;
952
953 kn->kn_sfflags = kev->fflags;
954 kn->kn_sdata = kev->data;
955 kev->fflags = 0;
956 kev->data = 0;
957 kn->kn_kevent = *kev;
958 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
959 EV_ENABLE | EV_DISABLE);
960 kn->kn_status = KN_INFLUX|KN_DETACHED;
961
962 error = knote_attach(kn, kq);
963 KQ_UNLOCK(kq);
964 if (error != 0) {
965 tkn = kn;
966 goto done;
967 }
968
969 if ((error = kn->kn_fop->f_attach(kn)) != 0) {
970 knote_drop(kn, td);
971 goto done;
972 }
973 KN_LIST_LOCK(kn);
974 } else {
975 /*
976 * The user may change some filter values after the
977 * initial EV_ADD, but doing so will not reset any
978 * filter which has already been triggered.
979 */
980 kn->kn_status |= KN_INFLUX;
981 KQ_UNLOCK(kq);
982 KN_LIST_LOCK(kn);
983 kn->kn_sfflags = kev->fflags;
984 kn->kn_sdata = kev->data;
985 kn->kn_kevent.udata = kev->udata;
986 }
987
988 /*
989 * We can get here with kn->kn_knlist == NULL.
990 * This can happen when the initial attach event decides that
|