1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
5 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org>
6 * Copyright (c) 2009 Apple, Inc.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <sys/cdefs.h>
32 #include "opt_ktrace.h"
33 #include "opt_kqueue.h"
34
35 #ifdef COMPAT_FREEBSD11
36 #define _WANT_FREEBSD11_KEVENT
37 #endif
38
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/capsicum.h>
42 #include <sys/kernel.h>
43 #include <sys/limits.h>
44 #include <sys/lock.h>
45 #include <sys/mutex.h>
46 #include <sys/proc.h>
47 #include <sys/malloc.h>
48 #include <sys/unistd.h>
49 #include <sys/file.h>
50 #include <sys/filedesc.h>
51 #include <sys/filio.h>
52 #include <sys/fcntl.h>
53 #include <sys/jail.h>
54 #include <sys/jaildesc.h>
55 #include <sys/kthread.h>
56 #include <sys/selinfo.h>
57 #include <sys/queue.h>
58 #include <sys/event.h>
59 #include <sys/eventvar.h>
60 #include <sys/poll.h>
61 #include <sys/protosw.h>
62 #include <sys/resourcevar.h>
63 #include <sys/sbuf.h>
64 #include <sys/sigio.h>
65 #include <sys/signalvar.h>
66 #include <sys/socket.h>
67 #include <sys/socketvar.h>
68 #include <sys/stat.h>
69 #include <sys/sysctl.h>
70 #include <sys/sysent.h>
71 #include <sys/sysproto.h>
72 #include <sys/syscallsubr.h>
73 #include <sys/taskqueue.h>
74 #include <sys/uio.h>
75 #include <sys/user.h>
76 #ifdef KTRACE
77 #include <sys/ktrace.h>
78 #endif
79 #include <machine/atomic.h>
80 #ifdef COMPAT_FREEBSD32
81 #include <compat/freebsd32/freebsd32.h>
82 #include <compat/freebsd32/freebsd32_util.h>
83 #endif
84
85 #include <vm/uma.h>
86
87 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
88
89 /*
90 * This lock is used if multiple kq locks are required. This possibly
91 * should be made into a per proc lock.
92 */
93 static struct mtx kq_global;
94 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF);
95 #define KQ_GLOBAL_LOCK(lck, haslck) do { \
96 if (!haslck) \
97 mtx_lock(lck); \
98 haslck = 1; \
99 } while (0)
100 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \
101 if (haslck) \
102 mtx_unlock(lck); \
103 haslck = 0; \
104 } while (0)
105
106 TASKQUEUE_DEFINE_THREAD(kqueue_ctx);
107
108 static int kevent_copyout(void *arg, struct kevent *kevp, int count);
109 static int kevent_copyin(void *arg, struct kevent *kevp, int count);
110 static int kqueue_register(struct kqueue *kq, struct kevent *kev,
111 struct thread *td, int mflag);
112 static int kqueue_acquire(struct file *fp, struct kqueue **kqp);
113 static void kqueue_release(struct kqueue *kq, int locked);
114 static void kqueue_destroy(struct kqueue *kq);
115 static void kqueue_drain(struct kqueue *kq, struct thread *td);
116 static int kqueue_expand(struct kqueue *kq, const struct filterops *fops,
117 uintptr_t ident, int mflag);
118 static void kqueue_task(void *arg, int pending);
119 static int kqueue_scan(struct kqueue *kq, int maxevents,
120 struct kevent_copyops *k_ops,
121 const struct timespec *timeout,
122 struct kevent *keva, struct thread *td);
123 static void kqueue_wakeup(struct kqueue *kq);
124 static const struct filterops *kqueue_fo_find(int filt);
125 static void kqueue_fo_release(int filt);
126 struct g_kevent_args;
127 static int kern_kevent_generic(struct thread *td,
128 struct g_kevent_args *uap,
129 struct kevent_copyops *k_ops, const char *struct_name);
130
131 static fo_ioctl_t kqueue_ioctl;
132 static fo_poll_t kqueue_poll;
133 static fo_kqfilter_t kqueue_kqfilter;
134 static fo_stat_t kqueue_stat;
135 static fo_close_t kqueue_close;
136 static fo_fill_kinfo_t kqueue_fill_kinfo;
137 static fo_fork_t kqueue_fork;
138
139 static const struct fileops kqueueops = {
140 .fo_read = invfo_rdwr,
141 .fo_write = invfo_rdwr,
142 .fo_truncate = invfo_truncate,
143 .fo_ioctl = kqueue_ioctl,
144 .fo_poll = kqueue_poll,
145 .fo_kqfilter = kqueue_kqfilter,
146 .fo_stat = kqueue_stat,
147 .fo_close = kqueue_close,
148 .fo_chmod = invfo_chmod,
149 .fo_chown = invfo_chown,
150 .fo_sendfile = invfo_sendfile,
151 .fo_cmp = file_kcmp_generic,
152 .fo_fork = kqueue_fork,
153 .fo_fill_kinfo = kqueue_fill_kinfo,
154 .fo_flags = DFLAG_FORK,
155 };
156
157 static int knote_attach(struct knote *kn, struct kqueue *kq);
158 static void knote_drop(struct knote *kn, struct thread *td);
159 static void knote_drop_detached(struct knote *kn, struct thread *td);
160 static void knote_enqueue(struct knote *kn);
161 static void knote_dequeue(struct knote *kn);
162 static void knote_init(void *);
163 static struct knote *knote_alloc(int mflag);
164 static void knote_free(struct knote *kn);
165
166 static void filt_kqdetach(struct knote *kn);
167 static int filt_kqueue(struct knote *kn, long hint);
168 static int filt_procattach(struct knote *kn);
169 static void filt_procdetach(struct knote *kn);
170 static int filt_proc(struct knote *kn, long hint);
171 static int filt_jailattach(struct knote *kn);
172 static void filt_jaildetach(struct knote *kn);
173 static int filt_jail(struct knote *kn, long hint);
174 static int filt_fileattach(struct knote *kn);
175 static void filt_timerexpire(void *knx);
176 static void filt_timerexpire_l(struct knote *kn, bool proc_locked);
177 static int filt_timerattach(struct knote *kn);
178 static void filt_timerdetach(struct knote *kn);
179 static void filt_timerstart(struct knote *kn, sbintime_t to);
180 static void filt_timertouch(struct knote *kn, struct kevent *kev,
181 u_long type);
182 static int filt_timercopy(struct knote *kn, struct proc *p1);
183 static int filt_timervalidate(struct knote *kn, sbintime_t *to);
184 static int filt_timer(struct knote *kn, long hint);
185 static int filt_userattach(struct knote *kn);
186 static void filt_userdetach(struct knote *kn);
187 static int filt_user(struct knote *kn, long hint);
188 static void filt_usertouch(struct knote *kn, struct kevent *kev,
189 u_long type);
190
191 static const struct filterops file_filtops = {
192 .f_isfd = 1,
193 .f_attach = filt_fileattach,
194 .f_copy = knote_triv_copy,
195 };
196 static const struct filterops kqread_filtops = {
197 .f_isfd = 1,
198 .f_detach = filt_kqdetach,
199 .f_event = filt_kqueue,
200 .f_copy = knote_triv_copy,
201 };
202 /* XXX - move to kern_proc.c? */
203 static const struct filterops proc_filtops = {
204 .f_isfd = 0,
205 .f_attach = filt_procattach,
206 .f_detach = filt_procdetach,
207 .f_event = filt_proc,
208 .f_copy = knote_triv_copy,
209 };
210 static const struct filterops jail_filtops = {
211 .f_isfd = 0,
212 .f_attach = filt_jailattach,
213 .f_detach = filt_jaildetach,
214 .f_event = filt_jail,
215 .f_copy = knote_triv_copy,
216 };
217 static const struct filterops timer_filtops = {
218 .f_isfd = 0,
219 .f_attach = filt_timerattach,
220 .f_detach = filt_timerdetach,
221 .f_event = filt_timer,
222 .f_touch = filt_timertouch,
223 .f_copy = filt_timercopy,
224 };
225 static const struct filterops user_filtops = {
226 .f_attach = filt_userattach,
227 .f_detach = filt_userdetach,
228 .f_event = filt_user,
229 .f_touch = filt_usertouch,
230 .f_copy = knote_triv_copy,
231 };
232
233 static uma_zone_t knote_zone;
234 static unsigned int __exclusive_cache_line kq_ncallouts;
235 static unsigned int kq_calloutmax = 4 * 1024;
236 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
237 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
238
239 /* XXX - ensure not influx ? */
240 #define KNOTE_ACTIVATE(kn, islock) do { \
241 if ((islock)) \
242 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \
243 else \
244 KQ_LOCK((kn)->kn_kq); \
245 (kn)->kn_status |= KN_ACTIVE; \
246 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
247 knote_enqueue((kn)); \
248 if (!(islock)) \
249 KQ_UNLOCK((kn)->kn_kq); \
250 } while (0)
251 #define KQ_LOCK(kq) do { \
252 mtx_lock(&(kq)->kq_lock); \
253 } while (0)
254 #define KQ_FLUX_WAKEUP(kq) do { \
255 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \
256 (kq)->kq_state &= ~KQ_FLUXWAIT; \
257 wakeup((kq)); \
258 } \
259 } while (0)
260 #define KQ_UNLOCK_FLUX(kq) do { \
261 KQ_FLUX_WAKEUP(kq); \
262 mtx_unlock(&(kq)->kq_lock); \
263 } while (0)
264 #define KQ_UNLOCK(kq) do { \
265 mtx_unlock(&(kq)->kq_lock); \
266 } while (0)
267 #define KQ_OWNED(kq) do { \
268 mtx_assert(&(kq)->kq_lock, MA_OWNED); \
269 } while (0)
270 #define KQ_NOTOWNED(kq) do { \
271 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \
272 } while (0)
273
274 static struct knlist *
kn_list_lock(struct knote * kn)275 kn_list_lock(struct knote *kn)
276 {
277 struct knlist *knl;
278
279 knl = kn->kn_knlist;
280 if (knl != NULL)
281 knl->kl_lock(knl->kl_lockarg);
282 return (knl);
283 }
284
285 static void
kn_list_unlock(struct knlist * knl)286 kn_list_unlock(struct knlist *knl)
287 {
288 bool do_free;
289
290 if (knl == NULL)
291 return;
292 do_free = knl->kl_autodestroy && knlist_empty(knl);
293 knl->kl_unlock(knl->kl_lockarg);
294 if (do_free) {
295 knlist_destroy(knl);
296 free(knl, M_KQUEUE);
297 }
298 }
299
300 static bool
kn_in_flux(struct knote * kn)301 kn_in_flux(struct knote *kn)
302 {
303
304 return (kn->kn_influx > 0);
305 }
306
307 static void
kn_enter_flux(struct knote * kn)308 kn_enter_flux(struct knote *kn)
309 {
310
311 KQ_OWNED(kn->kn_kq);
312 MPASS(kn->kn_influx < INT_MAX);
313 kn->kn_influx++;
314 }
315
316 static bool
kn_leave_flux(struct knote * kn)317 kn_leave_flux(struct knote *kn)
318 {
319
320 KQ_OWNED(kn->kn_kq);
321 MPASS(kn->kn_influx > 0);
322 kn->kn_influx--;
323 return (kn->kn_influx == 0);
324 }
325
326 #define KNL_ASSERT_LOCK(knl, islocked) do { \
327 if (islocked) \
328 KNL_ASSERT_LOCKED(knl); \
329 else \
330 KNL_ASSERT_UNLOCKED(knl); \
331 } while (0)
332 #ifdef INVARIANTS
333 #define KNL_ASSERT_LOCKED(knl) do { \
334 knl->kl_assert_lock((knl)->kl_lockarg, LA_LOCKED); \
335 } while (0)
336 #define KNL_ASSERT_UNLOCKED(knl) do { \
337 knl->kl_assert_lock((knl)->kl_lockarg, LA_UNLOCKED); \
338 } while (0)
339 #else /* !INVARIANTS */
340 #define KNL_ASSERT_LOCKED(knl) do {} while (0)
341 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
342 #endif /* INVARIANTS */
343
344 #ifndef KN_HASHSIZE
345 #define KN_HASHSIZE 64 /* XXX should be tunable */
346 #endif
347
348 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
349
350 static int
filt_nullattach(struct knote * kn)351 filt_nullattach(struct knote *kn)
352 {
353
354 return (ENXIO);
355 };
356
357 static const struct filterops null_filtops = {
358 .f_isfd = 0,
359 .f_attach = filt_nullattach,
360 .f_copy = knote_triv_copy,
361 };
362
363 /* XXX - make SYSINIT to add these, and move into respective modules. */
364 extern const struct filterops sig_filtops;
365 extern const struct filterops fs_filtops;
366
367 /*
368 * Table for all system-defined filters.
369 */
370 static struct mtx filterops_lock;
371 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", MTX_DEF);
372 static struct {
373 const struct filterops *for_fop;
374 int for_nolock;
375 int for_refcnt;
376 } sysfilt_ops[EVFILT_SYSCOUNT] = {
377 [~EVFILT_READ] = { &file_filtops, 1 },
378 [~EVFILT_WRITE] = { &file_filtops, 1 },
379 [~EVFILT_AIO] = { &null_filtops },
380 [~EVFILT_VNODE] = { &file_filtops, 1 },
381 [~EVFILT_PROC] = { &proc_filtops, 1 },
382 [~EVFILT_SIGNAL] = { &sig_filtops, 1 },
383 [~EVFILT_TIMER] = { &timer_filtops, 1 },
384 [~EVFILT_PROCDESC] = { &file_filtops, 1 },
385 [~EVFILT_FS] = { &fs_filtops, 1 },
386 [~EVFILT_LIO] = { &null_filtops },
387 [~EVFILT_USER] = { &user_filtops, 1 },
388 [~EVFILT_SENDFILE] = { &null_filtops },
389 [~EVFILT_EMPTY] = { &file_filtops, 1 },
390 [~EVFILT_JAIL] = { &jail_filtops, 1 },
391 [~EVFILT_JAILDESC] = { &file_filtops, 1 },
392 };
393
394 /*
395 * Simple redirection for all cdevsw style objects to call their fo_kqfilter
396 * method.
397 */
398 static int
filt_fileattach(struct knote * kn)399 filt_fileattach(struct knote *kn)
400 {
401
402 return (fo_kqfilter(kn->kn_fp, kn));
403 }
404
405 /*ARGSUSED*/
406 static int
kqueue_kqfilter(struct file * fp,struct knote * kn)407 kqueue_kqfilter(struct file *fp, struct knote *kn)
408 {
409 struct kqueue *kq = kn->kn_fp->f_data;
410
411 if (kn->kn_filter != EVFILT_READ)
412 return (EINVAL);
413
414 kn->kn_status |= KN_KQUEUE;
415 kn->kn_fop = &kqread_filtops;
416 knlist_add(&kq->kq_sel.si_note, kn, 0);
417
418 return (0);
419 }
420
421 static void
filt_kqdetach(struct knote * kn)422 filt_kqdetach(struct knote *kn)
423 {
424 struct kqueue *kq = kn->kn_fp->f_data;
425
426 knlist_remove(&kq->kq_sel.si_note, kn, 0);
427 }
428
429 /*ARGSUSED*/
430 static int
filt_kqueue(struct knote * kn,long hint)431 filt_kqueue(struct knote *kn, long hint)
432 {
433 struct kqueue *kq = kn->kn_fp->f_data;
434
435 kn->kn_data = kq->kq_count;
436 return (kn->kn_data > 0);
437 }
438
439 /* XXX - move to kern_proc.c? */
440 static int
filt_procattach(struct knote * kn)441 filt_procattach(struct knote *kn)
442 {
443 struct proc *p;
444 int error;
445 bool exiting, immediate;
446
447 exiting = immediate = false;
448 if (kn->kn_sfflags & NOTE_EXIT)
449 p = pfind_any(kn->kn_id);
450 else
451 p = pfind(kn->kn_id);
452 if (p == NULL)
453 return (ESRCH);
454 if (p->p_flag & P_WEXIT)
455 exiting = true;
456
457 if ((error = p_cansee(curthread, p))) {
458 PROC_UNLOCK(p);
459 return (error);
460 }
461
462 kn->kn_ptr.p_proc = p;
463 kn->kn_flags |= EV_CLEAR; /* automatically set */
464
465 /*
466 * Internal flag indicating registration done by kernel for the
467 * purposes of getting a NOTE_CHILD notification.
468 */
469 if (kn->kn_flags & EV_FLAG2) {
470 kn->kn_flags &= ~EV_FLAG2;
471 kn->kn_data = kn->kn_sdata; /* ppid */
472 kn->kn_fflags = NOTE_CHILD;
473 kn->kn_sfflags &= ~(NOTE_EXIT | NOTE_EXEC | NOTE_FORK);
474 immediate = true; /* Force immediate activation of child note. */
475 }
476 /*
477 * Internal flag indicating registration done by kernel (for other than
478 * NOTE_CHILD).
479 */
480 if (kn->kn_flags & EV_FLAG1) {
481 kn->kn_flags &= ~EV_FLAG1;
482 }
483
484 knlist_add(p->p_klist, kn, 1);
485
486 /*
487 * Immediately activate any child notes or, in the case of a zombie
488 * target process, exit notes. The latter is necessary to handle the
489 * case where the target process, e.g. a child, dies before the kevent
490 * is registered.
491 */
492 if (immediate || (exiting && filt_proc(kn, NOTE_EXIT)))
493 KNOTE_ACTIVATE(kn, 0);
494
495 PROC_UNLOCK(p);
496
497 return (0);
498 }
499
500 /*
501 * The knote may be attached to a different process, which may exit,
502 * leaving nothing for the knote to be attached to. So when the process
503 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
504 * it will be deleted when read out. However, as part of the knote deletion,
505 * this routine is called, so a check is needed to avoid actually performing
506 * a detach, because the original process does not exist any more.
507 */
508 /* XXX - move to kern_proc.c? */
509 static void
filt_procdetach(struct knote * kn)510 filt_procdetach(struct knote *kn)
511 {
512
513 knlist_remove(kn->kn_knlist, kn, 0);
514 kn->kn_ptr.p_proc = NULL;
515 }
516
517 /* XXX - move to kern_proc.c? */
518 static int
filt_proc(struct knote * kn,long hint)519 filt_proc(struct knote *kn, long hint)
520 {
521 struct proc *p;
522 u_int event;
523
524 p = kn->kn_ptr.p_proc;
525 if (p == NULL) /* already activated, from attach filter */
526 return (0);
527
528 /* Mask off extra data. */
529 event = (u_int)hint & NOTE_PCTRLMASK;
530
531 /* If the user is interested in this event, record it. */
532 if (kn->kn_sfflags & event)
533 kn->kn_fflags |= event;
534
535 /* Process is gone, so flag the event as finished. */
536 if (event == NOTE_EXIT) {
537 kn->kn_flags |= EV_EOF | EV_ONESHOT;
538 kn->kn_ptr.p_proc = NULL;
539 if (kn->kn_fflags & NOTE_EXIT)
540 kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig);
541 if (kn->kn_fflags == 0)
542 kn->kn_flags |= EV_DROP;
543 return (1);
544 }
545
546 return (kn->kn_fflags != 0);
547 }
548
549 /*
550 * Called when the process forked. It mostly does the same as the
551 * knote(), activating all knotes registered to be activated when the
552 * process forked. Additionally, for each knote attached to the
553 * parent, check whether user wants to track the new process. If so
554 * attach a new knote to it, and immediately report an event with the
555 * child's pid.
556 */
557 void
knote_fork(struct knlist * list,int pid)558 knote_fork(struct knlist *list, int pid)
559 {
560 struct kqueue *kq;
561 struct knote *kn;
562 struct kevent kev;
563 int error;
564
565 MPASS(list != NULL);
566 KNL_ASSERT_LOCKED(list);
567 if (SLIST_EMPTY(&list->kl_list))
568 return;
569
570 memset(&kev, 0, sizeof(kev));
571 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
572 kq = kn->kn_kq;
573 KQ_LOCK(kq);
574 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) {
575 KQ_UNLOCK(kq);
576 continue;
577 }
578
579 /*
580 * The same as knote(), activate the event.
581 */
582 if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
583 if (kn->kn_fop->f_event(kn, NOTE_FORK))
584 KNOTE_ACTIVATE(kn, 1);
585 KQ_UNLOCK(kq);
586 continue;
587 }
588
589 /*
590 * The NOTE_TRACK case. In addition to the activation
591 * of the event, we need to register new events to
592 * track the child. Drop the locks in preparation for
593 * the call to kqueue_register().
594 */
595 kn_enter_flux(kn);
596 KQ_UNLOCK(kq);
597 list->kl_unlock(list->kl_lockarg);
598
599 /*
600 * Activate existing knote and register tracking knotes with
601 * new process.
602 *
603 * First register a knote to get just the child notice. This
604 * must be a separate note from a potential NOTE_EXIT
605 * notification since both NOTE_CHILD and NOTE_EXIT are defined
606 * to use the data field (in conflicting ways).
607 */
608 kev.ident = pid;
609 kev.filter = kn->kn_filter;
610 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT |
611 EV_FLAG2;
612 kev.fflags = kn->kn_sfflags;
613 kev.data = kn->kn_id; /* parent */
614 kev.udata = kn->kn_kevent.udata;/* preserve udata */
615 error = kqueue_register(kq, &kev, NULL, M_NOWAIT);
616 if (error)
617 kn->kn_fflags |= NOTE_TRACKERR;
618
619 /*
620 * Then register another knote to track other potential events
621 * from the new process.
622 */
623 kev.ident = pid;
624 kev.filter = kn->kn_filter;
625 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
626 kev.fflags = kn->kn_sfflags;
627 kev.data = kn->kn_id; /* parent */
628 kev.udata = kn->kn_kevent.udata;/* preserve udata */
629 error = kqueue_register(kq, &kev, NULL, M_NOWAIT);
630 if (error)
631 kn->kn_fflags |= NOTE_TRACKERR;
632 if (kn->kn_fop->f_event(kn, NOTE_FORK))
633 KNOTE_ACTIVATE(kn, 0);
634 list->kl_lock(list->kl_lockarg);
635 KQ_LOCK(kq);
636 kn_leave_flux(kn);
637 KQ_UNLOCK_FLUX(kq);
638 }
639 }
640
641 int
filt_jailattach(struct knote * kn)642 filt_jailattach(struct knote *kn)
643 {
644 struct prison *pr;
645
646 if (kn->kn_id == 0) {
647 /* Let jid=0 watch the current prison (including prison0). */
648 pr = curthread->td_ucred->cr_prison;
649 mtx_lock(&pr->pr_mtx);
650 } else {
651 sx_slock(&allprison_lock);
652 pr = prison_find_child(curthread->td_ucred->cr_prison,
653 kn->kn_id);
654 sx_sunlock(&allprison_lock);
655 if (pr == NULL)
656 return (ENOENT);
657 if (!prison_isalive(pr)) {
658 mtx_unlock(&pr->pr_mtx);
659 return (ENOENT);
660 }
661 }
662 kn->kn_ptr.p_prison = pr;
663 kn->kn_flags |= EV_CLEAR;
664 knlist_add(pr->pr_klist, kn, 1);
665 mtx_unlock(&pr->pr_mtx);
666 return (0);
667 }
668
669 void
filt_jaildetach(struct knote * kn)670 filt_jaildetach(struct knote *kn)
671 {
672 if (kn->kn_ptr.p_prison != NULL) {
673 knlist_remove(kn->kn_knlist, kn, 0);
674 kn->kn_ptr.p_prison = NULL;
675 } else
676 kn->kn_status |= KN_DETACHED;
677 }
678
679 int
filt_jail(struct knote * kn,long hint)680 filt_jail(struct knote *kn, long hint)
681 {
682 struct prison *pr;
683 u_int event;
684
685 pr = kn->kn_ptr.p_prison;
686 if (pr == NULL) /* already activated, from attach filter */
687 return (0);
688
689 /*
690 * Mask off extra data. In the NOTE_JAIL_CHILD case, that's
691 * everything except the NOTE_JAIL_CHILD bit itself, since a
692 * JID is any positive integer.
693 */
694 event = ((u_int)hint & NOTE_JAIL_CHILD) ? NOTE_JAIL_CHILD :
695 (u_int)hint & NOTE_JAIL_CTRLMASK;
696
697 /* If the user is interested in this event, record it. */
698 if (kn->kn_sfflags & event) {
699 kn->kn_fflags |= event;
700 /* Report the created jail id or attached process id. */
701 if (event == NOTE_JAIL_CHILD || event == NOTE_JAIL_ATTACH) {
702 if (kn->kn_data != 0)
703 kn->kn_fflags |= NOTE_JAIL_MULTI;
704 kn->kn_data = (kn->kn_fflags & NOTE_JAIL_MULTI) ? 0U :
705 (u_int)hint & ~event;
706 }
707 }
708
709 /* Prison is gone, so flag the event as finished. */
710 if (event == NOTE_JAIL_REMOVE) {
711 kn->kn_flags |= EV_EOF | EV_ONESHOT;
712 kn->kn_ptr.p_prison = NULL;
713 if (kn->kn_fflags == 0)
714 kn->kn_flags |= EV_DROP;
715 return (1);
716 }
717
718 return (kn->kn_fflags != 0);
719 }
720
721 /*
722 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the
723 * interval timer support code.
724 */
725
726 #define NOTE_TIMER_PRECMASK \
727 (NOTE_SECONDS | NOTE_MSECONDS | NOTE_USECONDS | NOTE_NSECONDS)
728
729 static sbintime_t
timer2sbintime(int64_t data,int flags)730 timer2sbintime(int64_t data, int flags)
731 {
732 int64_t secs;
733
734 /*
735 * Macros for converting to the fractional second portion of an
736 * sbintime_t using 64bit multiplication to improve precision.
737 */
738 #define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32)
739 #define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32)
740 #define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32)
741 switch (flags & NOTE_TIMER_PRECMASK) {
742 case NOTE_SECONDS:
743 #ifdef __LP64__
744 if (data > (SBT_MAX / SBT_1S))
745 return (SBT_MAX);
746 #endif
747 return ((sbintime_t)data << 32);
748 case NOTE_MSECONDS: /* FALLTHROUGH */
749 case 0:
750 if (data >= 1000) {
751 secs = data / 1000;
752 #ifdef __LP64__
753 if (secs > (SBT_MAX / SBT_1S))
754 return (SBT_MAX);
755 #endif
756 return (secs << 32 | MS_TO_SBT(data % 1000));
757 }
758 return (MS_TO_SBT(data));
759 case NOTE_USECONDS:
760 if (data >= 1000000) {
761 secs = data / 1000000;
762 #ifdef __LP64__
763 if (secs > (SBT_MAX / SBT_1S))
764 return (SBT_MAX);
765 #endif
766 return (secs << 32 | US_TO_SBT(data % 1000000));
767 }
768 return (US_TO_SBT(data));
769 case NOTE_NSECONDS:
770 if (data >= 1000000000) {
771 secs = data / 1000000000;
772 #ifdef __LP64__
773 if (secs > (SBT_MAX / SBT_1S))
774 return (SBT_MAX);
775 #endif
776 return (secs << 32 | NS_TO_SBT(data % 1000000000));
777 }
778 return (NS_TO_SBT(data));
779 default:
780 break;
781 }
782 return (-1);
783 }
784
785 struct kq_timer_cb_data {
786 struct callout c;
787 struct proc *p;
788 struct knote *kn;
789 int cpuid;
790 int flags;
791 TAILQ_ENTRY(kq_timer_cb_data) link;
792 sbintime_t next; /* next timer event fires at */
793 sbintime_t to; /* precalculated timer period, 0 for abs */
794 };
795
796 #define KQ_TIMER_CB_ENQUEUED 0x01
797
798 static void
kqtimer_sched_callout(struct kq_timer_cb_data * kc)799 kqtimer_sched_callout(struct kq_timer_cb_data *kc)
800 {
801 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kc->kn,
802 kc->cpuid, C_ABSOLUTE);
803 }
804
805 void
kqtimer_proc_continue(struct proc * p)806 kqtimer_proc_continue(struct proc *p)
807 {
808 struct kq_timer_cb_data *kc, *kc1;
809 struct bintime bt;
810 sbintime_t now;
811
812 PROC_LOCK_ASSERT(p, MA_OWNED);
813
814 getboottimebin(&bt);
815 now = bttosbt(bt);
816
817 TAILQ_FOREACH_SAFE(kc, &p->p_kqtim_stop, link, kc1) {
818 TAILQ_REMOVE(&p->p_kqtim_stop, kc, link);
819 kc->flags &= ~KQ_TIMER_CB_ENQUEUED;
820 if (kc->next <= now)
821 filt_timerexpire_l(kc->kn, true);
822 else
823 kqtimer_sched_callout(kc);
824 }
825 }
826
827 static void
filt_timerexpire_l(struct knote * kn,bool proc_locked)828 filt_timerexpire_l(struct knote *kn, bool proc_locked)
829 {
830 struct kq_timer_cb_data *kc;
831 struct proc *p;
832 uint64_t delta;
833 sbintime_t now;
834
835 kc = kn->kn_ptr.p_v;
836
837 if ((kn->kn_flags & EV_ONESHOT) != 0 || kc->to == 0) {
838 kn->kn_data++;
839 KNOTE_ACTIVATE(kn, 0);
840 return;
841 }
842
843 now = sbinuptime();
844 if (now >= kc->next) {
845 delta = (now - kc->next) / kc->to;
846 if (delta == 0)
847 delta = 1;
848 kn->kn_data += delta;
849 kc->next += delta * kc->to;
850 if (now >= kc->next) /* overflow */
851 kc->next = now + kc->to;
852 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
853 }
854
855 /*
856 * Initial check for stopped kc->p is racy. It is fine to
857 * miss the set of the stop flags, at worst we would schedule
858 * one more callout. On the other hand, it is not fine to not
859 * schedule when we we missed clearing of the flags, we
860 * recheck them under the lock and observe consistent state.
861 */
862 p = kc->p;
863 if (P_SHOULDSTOP(p) || P_KILLED(p)) {
864 if (!proc_locked)
865 PROC_LOCK(p);
866 if (P_SHOULDSTOP(p) || P_KILLED(p)) {
867 if ((kc->flags & KQ_TIMER_CB_ENQUEUED) == 0) {
868 kc->flags |= KQ_TIMER_CB_ENQUEUED;
869 TAILQ_INSERT_TAIL(&p->p_kqtim_stop, kc, link);
870 }
871 if (!proc_locked)
872 PROC_UNLOCK(p);
873 return;
874 }
875 if (!proc_locked)
876 PROC_UNLOCK(p);
877 }
878 kqtimer_sched_callout(kc);
879 }
880
881 static void
filt_timerexpire(void * knx)882 filt_timerexpire(void *knx)
883 {
884 filt_timerexpire_l(knx, false);
885 }
886
887 /*
888 * data contains amount of time to sleep
889 */
890 static int
filt_timervalidate(struct knote * kn,sbintime_t * to)891 filt_timervalidate(struct knote *kn, sbintime_t *to)
892 {
893 struct bintime bt;
894 sbintime_t sbt;
895
896 if (kn->kn_sdata < 0)
897 return (EINVAL);
898 if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0)
899 kn->kn_sdata = 1;
900 /*
901 * The only fflags values supported are the timer unit
902 * (precision) and the absolute time indicator.
903 */
904 if ((kn->kn_sfflags & ~(NOTE_TIMER_PRECMASK | NOTE_ABSTIME)) != 0)
905 return (EINVAL);
906
907 *to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags);
908 if (*to < 0)
909 return (EINVAL);
910 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) {
911 getboottimebin(&bt);
912 sbt = bttosbt(bt);
913 *to = MAX(0, *to - sbt);
914 }
915 return (0);
916 }
917
918 static int
filt_timerattach(struct knote * kn)919 filt_timerattach(struct knote *kn)
920 {
921 struct kq_timer_cb_data *kc;
922 sbintime_t to;
923 int error;
924
925 to = -1;
926 error = filt_timervalidate(kn, &to);
927 if (error != 0)
928 return (error);
929 KASSERT(to > 0 || (kn->kn_flags & EV_ONESHOT) != 0 ||
930 (kn->kn_sfflags & NOTE_ABSTIME) != 0,
931 ("%s: periodic timer has a calculated zero timeout", __func__));
932 KASSERT(to >= 0,
933 ("%s: timer has a calculated negative timeout", __func__));
934
935 if (atomic_fetchadd_int(&kq_ncallouts, 1) + 1 > kq_calloutmax) {
936 atomic_subtract_int(&kq_ncallouts, 1);
937 return (ENOMEM);
938 }
939
940 if ((kn->kn_sfflags & NOTE_ABSTIME) == 0)
941 kn->kn_flags |= EV_CLEAR; /* automatically set */
942 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */
943 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK);
944 kc->kn = kn;
945 kc->p = curproc;
946 kc->cpuid = PCPU_GET(cpuid);
947 kc->flags = 0;
948 callout_init(&kc->c, 1);
949 filt_timerstart(kn, to);
950
951 return (0);
952 }
953
954 static int
filt_timercopy(struct knote * kn,struct proc * p)955 filt_timercopy(struct knote *kn, struct proc *p)
956 {
957 struct kq_timer_cb_data *kc_src, *kc;
958
959 if (atomic_fetchadd_int(&kq_ncallouts, 1) + 1 > kq_calloutmax) {
960 atomic_subtract_int(&kq_ncallouts, 1);
961 return (ENOMEM);
962 }
963
964 kn->kn_status &= ~KN_DETACHED;
965 kc_src = kn->kn_ptr.p_v;
966 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK);
967 kc->kn = kn;
968 kc->p = p;
969 kc->flags = kc_src->flags & ~KQ_TIMER_CB_ENQUEUED;
970 kc->next = kc_src->next;
971 kc->to = kc_src->to;
972 kc->cpuid = PCPU_GET(cpuid);
973 callout_init(&kc->c, 1);
974 kqtimer_sched_callout(kc);
975 return (0);
976 }
977
978 static void
filt_timerstart(struct knote * kn,sbintime_t to)979 filt_timerstart(struct knote *kn, sbintime_t to)
980 {
981 struct kq_timer_cb_data *kc;
982
983 kc = kn->kn_ptr.p_v;
984 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) {
985 kc->next = to;
986 kc->to = 0;
987 } else {
988 kc->next = to + sbinuptime();
989 kc->to = to;
990 }
991 kqtimer_sched_callout(kc);
992 }
993
994 static void
filt_timerdetach(struct knote * kn)995 filt_timerdetach(struct knote *kn)
996 {
997 struct kq_timer_cb_data *kc;
998 unsigned int old __unused;
999 bool pending;
1000
1001 kc = kn->kn_ptr.p_v;
1002 do {
1003 callout_drain(&kc->c);
1004
1005 /*
1006 * kqtimer_proc_continue() might have rescheduled this callout.
1007 * Double-check, using the process mutex as an interlock.
1008 */
1009 PROC_LOCK(kc->p);
1010 if ((kc->flags & KQ_TIMER_CB_ENQUEUED) != 0) {
1011 kc->flags &= ~KQ_TIMER_CB_ENQUEUED;
1012 TAILQ_REMOVE(&kc->p->p_kqtim_stop, kc, link);
1013 }
1014 pending = callout_pending(&kc->c);
1015 PROC_UNLOCK(kc->p);
1016 } while (pending);
1017 free(kc, M_KQUEUE);
1018 old = atomic_fetchadd_int(&kq_ncallouts, -1);
1019 KASSERT(old > 0, ("Number of callouts cannot become negative"));
1020 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */
1021 }
1022
1023 static void
filt_timertouch(struct knote * kn,struct kevent * kev,u_long type)1024 filt_timertouch(struct knote *kn, struct kevent *kev, u_long type)
1025 {
1026 struct kq_timer_cb_data *kc;
1027 struct kqueue *kq;
1028 sbintime_t to;
1029 int error;
1030
1031 switch (type) {
1032 case EVENT_REGISTER:
1033 /* Handle re-added timers that update data/fflags */
1034 if (kev->flags & EV_ADD) {
1035 kc = kn->kn_ptr.p_v;
1036
1037 /* Drain any existing callout. */
1038 callout_drain(&kc->c);
1039
1040 /* Throw away any existing undelivered record
1041 * of the timer expiration. This is done under
1042 * the presumption that if a process is
1043 * re-adding this timer with new parameters,
1044 * it is no longer interested in what may have
1045 * happened under the old parameters. If it is
1046 * interested, it can wait for the expiration,
1047 * delete the old timer definition, and then
1048 * add the new one.
1049 *
1050 * This has to be done while the kq is locked:
1051 * - if enqueued, dequeue
1052 * - make it no longer active
1053 * - clear the count of expiration events
1054 */
1055 kq = kn->kn_kq;
1056 KQ_LOCK(kq);
1057 if (kn->kn_status & KN_QUEUED)
1058 knote_dequeue(kn);
1059
1060 kn->kn_status &= ~KN_ACTIVE;
1061 kn->kn_data = 0;
1062 KQ_UNLOCK(kq);
1063
1064 /* Reschedule timer based on new data/fflags */
1065 kn->kn_sfflags = kev->fflags;
1066 kn->kn_sdata = kev->data;
1067 error = filt_timervalidate(kn, &to);
1068 if (error != 0) {
1069 kn->kn_flags |= EV_ERROR;
1070 kn->kn_data = error;
1071 } else
1072 filt_timerstart(kn, to);
1073 }
1074 break;
1075
1076 case EVENT_PROCESS:
1077 *kev = kn->kn_kevent;
1078 if (kn->kn_flags & EV_CLEAR) {
1079 kn->kn_data = 0;
1080 kn->kn_fflags = 0;
1081 }
1082 break;
1083
1084 default:
1085 panic("filt_timertouch() - invalid type (%ld)", type);
1086 break;
1087 }
1088 }
1089
1090 static int
filt_timer(struct knote * kn,long hint)1091 filt_timer(struct knote *kn, long hint)
1092 {
1093
1094 return (kn->kn_data != 0);
1095 }
1096
1097 static int
filt_userattach(struct knote * kn)1098 filt_userattach(struct knote *kn)
1099 {
1100
1101 /*
1102 * EVFILT_USER knotes are not attached to anything in the kernel.
1103 */
1104 kn->kn_hook = NULL;
1105 if (kn->kn_fflags & NOTE_TRIGGER)
1106 kn->kn_hookid = 1;
1107 else
1108 kn->kn_hookid = 0;
1109 return (0);
1110 }
1111
1112 static void
filt_userdetach(__unused struct knote * kn)1113 filt_userdetach(__unused struct knote *kn)
1114 {
1115
1116 /*
1117 * EVFILT_USER knotes are not attached to anything in the kernel.
1118 */
1119 }
1120
1121 static int
filt_user(struct knote * kn,__unused long hint)1122 filt_user(struct knote *kn, __unused long hint)
1123 {
1124
1125 return (kn->kn_hookid);
1126 }
1127
1128 static void
filt_usertouch(struct knote * kn,struct kevent * kev,u_long type)1129 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
1130 {
1131 u_int ffctrl;
1132
1133 switch (type) {
1134 case EVENT_REGISTER:
1135 if (kev->fflags & NOTE_TRIGGER)
1136 kn->kn_hookid = 1;
1137
1138 ffctrl = kev->fflags & NOTE_FFCTRLMASK;
1139 kev->fflags &= NOTE_FFLAGSMASK;
1140 switch (ffctrl) {
1141 case NOTE_FFNOP:
1142 break;
1143
1144 case NOTE_FFAND:
1145 kn->kn_sfflags &= kev->fflags;
1146 break;
1147
1148 case NOTE_FFOR:
1149 kn->kn_sfflags |= kev->fflags;
1150 break;
1151
1152 case NOTE_FFCOPY:
1153 kn->kn_sfflags = kev->fflags;
1154 break;
1155
1156 default:
1157 /* XXX Return error? */
1158 break;
1159 }
1160 kn->kn_sdata = kev->data;
1161 if (kev->flags & EV_CLEAR) {
1162 kn->kn_hookid = 0;
1163 kn->kn_data = 0;
1164 kn->kn_fflags = 0;
1165 }
1166 break;
1167
1168 case EVENT_PROCESS:
1169 *kev = kn->kn_kevent;
1170 kev->fflags = kn->kn_sfflags;
1171 kev->data = kn->kn_sdata;
1172 if (kn->kn_flags & EV_CLEAR) {
1173 kn->kn_hookid = 0;
1174 kn->kn_data = 0;
1175 kn->kn_fflags = 0;
1176 }
1177 break;
1178
1179 default:
1180 panic("filt_usertouch() - invalid type (%ld)", type);
1181 break;
1182 }
1183 }
1184
1185 int
sys_kqueue(struct thread * td,struct kqueue_args * uap)1186 sys_kqueue(struct thread *td, struct kqueue_args *uap)
1187 {
1188
1189 return (kern_kqueue(td, 0, false, NULL));
1190 }
1191
1192 int
sys_kqueuex(struct thread * td,struct kqueuex_args * uap)1193 sys_kqueuex(struct thread *td, struct kqueuex_args *uap)
1194 {
1195 int flags;
1196
1197 if ((uap->flags & ~(KQUEUE_CLOEXEC | KQUEUE_CPONFORK)) != 0)
1198 return (EINVAL);
1199 flags = 0;
1200 if ((uap->flags & KQUEUE_CLOEXEC) != 0)
1201 flags |= O_CLOEXEC;
1202 return (kern_kqueue(td, flags, (uap->flags & KQUEUE_CPONFORK) != 0,
1203 NULL));
1204 }
1205
1206 static void
kqueue_init(struct kqueue * kq,bool cponfork)1207 kqueue_init(struct kqueue *kq, bool cponfork)
1208 {
1209
1210 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK);
1211 TAILQ_INIT(&kq->kq_head);
1212 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
1213 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
1214 if (cponfork)
1215 kq->kq_state |= KQ_CPONFORK;
1216 }
1217
1218 static int
kern_kqueue_alloc(struct thread * td,struct filedesc * fdp,int * fdip,struct file ** fpp,int flags,struct filecaps * fcaps,bool cponfork,struct kqueue ** kqp)1219 kern_kqueue_alloc(struct thread *td, struct filedesc *fdp, int *fdip,
1220 struct file **fpp, int flags, struct filecaps *fcaps, bool cponfork,
1221 struct kqueue **kqp)
1222 {
1223 struct ucred *cred;
1224 struct kqueue *kq;
1225 int error;
1226
1227 cred = td->td_ucred;
1228 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES)))
1229 return (ENOMEM);
1230
1231 error = fdip != NULL ? falloc_caps(td, fpp, fdip, flags, fcaps) :
1232 _falloc_noinstall(td, fpp, 1);
1233 if (error != 0) {
1234 chgkqcnt(cred->cr_ruidinfo, -1, 0);
1235 return (error);
1236 }
1237
1238 /* An extra reference on `fp' has been held for us by falloc(). */
1239 kq = malloc(sizeof(*kq), M_KQUEUE, M_WAITOK | M_ZERO);
1240 kqueue_init(kq, cponfork);
1241 kq->kq_fdp = fdp;
1242 kq->kq_cred = crhold(cred);
1243
1244 if (fdip != NULL)
1245 FILEDESC_XLOCK(fdp);
1246 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
1247 if (fdip != NULL)
1248 FILEDESC_XUNLOCK(fdp);
1249
1250 finit(*fpp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
1251 *kqp = kq;
1252 return (0);
1253 }
1254
1255 int
kern_kqueue(struct thread * td,int flags,bool cponfork,struct filecaps * fcaps)1256 kern_kqueue(struct thread *td, int flags, bool cponfork, struct filecaps *fcaps)
1257 {
1258 struct kqueue *kq;
1259 struct file *fp;
1260 int fd, error;
1261
1262 error = kern_kqueue_alloc(td, td->td_proc->p_fd, &fd, &fp, flags,
1263 fcaps, cponfork, &kq);
1264 if (error != 0)
1265 return (error);
1266
1267 fdrop(fp, td);
1268
1269 td->td_retval[0] = fd;
1270 return (0);
1271 }
1272
1273 struct g_kevent_args {
1274 int fd;
1275 const void *changelist;
1276 int nchanges;
1277 void *eventlist;
1278 int nevents;
1279 const struct timespec *timeout;
1280 };
1281
1282 int
sys_kevent(struct thread * td,struct kevent_args * uap)1283 sys_kevent(struct thread *td, struct kevent_args *uap)
1284 {
1285 struct kevent_copyops k_ops = {
1286 .arg = uap,
1287 .k_copyout = kevent_copyout,
1288 .k_copyin = kevent_copyin,
1289 .kevent_size = sizeof(struct kevent),
1290 };
1291 struct g_kevent_args gk_args = {
1292 .fd = uap->fd,
1293 .changelist = uap->changelist,
1294 .nchanges = uap->nchanges,
1295 .eventlist = uap->eventlist,
1296 .nevents = uap->nevents,
1297 .timeout = uap->timeout,
1298 };
1299
1300 return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent"));
1301 }
1302
1303 static int
kern_kevent_generic(struct thread * td,struct g_kevent_args * uap,struct kevent_copyops * k_ops,const char * struct_name)1304 kern_kevent_generic(struct thread *td, struct g_kevent_args *uap,
1305 struct kevent_copyops *k_ops, const char *struct_name)
1306 {
1307 struct timespec ts, *tsp;
1308 #ifdef KTRACE
1309 struct kevent *eventlist = uap->eventlist;
1310 #endif
1311 int error;
1312
1313 if (uap->timeout != NULL) {
1314 error = copyin(uap->timeout, &ts, sizeof(ts));
1315 if (error)
1316 return (error);
1317 tsp = &ts;
1318 } else
1319 tsp = NULL;
1320
1321 #ifdef KTRACE
1322 if (KTRPOINT(td, KTR_STRUCT_ARRAY))
1323 ktrstructarray(struct_name, UIO_USERSPACE, uap->changelist,
1324 uap->nchanges, k_ops->kevent_size);
1325 #endif
1326
1327 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
1328 k_ops, tsp);
1329
1330 #ifdef KTRACE
1331 if (error == 0 && KTRPOINT(td, KTR_STRUCT_ARRAY))
1332 ktrstructarray(struct_name, UIO_USERSPACE, eventlist,
1333 td->td_retval[0], k_ops->kevent_size);
1334 #endif
1335
1336 return (error);
1337 }
1338
1339 /*
1340 * Copy 'count' items into the destination list pointed to by uap->eventlist.
1341 */
1342 static int
kevent_copyout(void * arg,struct kevent * kevp,int count)1343 kevent_copyout(void *arg, struct kevent *kevp, int count)
1344 {
1345 struct kevent_args *uap;
1346 int error;
1347
1348 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1349 uap = (struct kevent_args *)arg;
1350
1351 error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
1352 if (error == 0)
1353 uap->eventlist += count;
1354 return (error);
1355 }
1356
1357 /*
1358 * Copy 'count' items from the list pointed to by uap->changelist.
1359 */
1360 static int
kevent_copyin(void * arg,struct kevent * kevp,int count)1361 kevent_copyin(void *arg, struct kevent *kevp, int count)
1362 {
1363 struct kevent_args *uap;
1364 int error;
1365
1366 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1367 uap = (struct kevent_args *)arg;
1368
1369 error = copyin(uap->changelist, kevp, count * sizeof *kevp);
1370 if (error == 0)
1371 uap->changelist += count;
1372 return (error);
1373 }
1374
1375 #ifdef COMPAT_FREEBSD11
1376 static int
kevent11_copyout(void * arg,struct kevent * kevp,int count)1377 kevent11_copyout(void *arg, struct kevent *kevp, int count)
1378 {
1379 struct freebsd11_kevent_args *uap;
1380 struct freebsd11_kevent kev11;
1381 int error, i;
1382
1383 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1384 uap = (struct freebsd11_kevent_args *)arg;
1385
1386 for (i = 0; i < count; i++) {
1387 kev11.ident = kevp->ident;
1388 kev11.filter = kevp->filter;
1389 kev11.flags = kevp->flags;
1390 kev11.fflags = kevp->fflags;
1391 kev11.data = kevp->data;
1392 kev11.udata = kevp->udata;
1393 error = copyout(&kev11, uap->eventlist, sizeof(kev11));
1394 if (error != 0)
1395 break;
1396 uap->eventlist++;
1397 kevp++;
1398 }
1399 return (error);
1400 }
1401
1402 /*
1403 * Copy 'count' items from the list pointed to by uap->changelist.
1404 */
1405 static int
kevent11_copyin(void * arg,struct kevent * kevp,int count)1406 kevent11_copyin(void *arg, struct kevent *kevp, int count)
1407 {
1408 struct freebsd11_kevent_args *uap;
1409 struct freebsd11_kevent kev11;
1410 int error, i;
1411
1412 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1413 uap = (struct freebsd11_kevent_args *)arg;
1414
1415 for (i = 0; i < count; i++) {
1416 error = copyin(uap->changelist, &kev11, sizeof(kev11));
1417 if (error != 0)
1418 break;
1419 kevp->ident = kev11.ident;
1420 kevp->filter = kev11.filter;
1421 kevp->flags = kev11.flags;
1422 kevp->fflags = kev11.fflags;
1423 kevp->data = (uintptr_t)kev11.data;
1424 kevp->udata = kev11.udata;
1425 bzero(&kevp->ext, sizeof(kevp->ext));
1426 uap->changelist++;
1427 kevp++;
1428 }
1429 return (error);
1430 }
1431
1432 int
freebsd11_kevent(struct thread * td,struct freebsd11_kevent_args * uap)1433 freebsd11_kevent(struct thread *td, struct freebsd11_kevent_args *uap)
1434 {
1435 struct kevent_copyops k_ops = {
1436 .arg = uap,
1437 .k_copyout = kevent11_copyout,
1438 .k_copyin = kevent11_copyin,
1439 .kevent_size = sizeof(struct freebsd11_kevent),
1440 };
1441 struct g_kevent_args gk_args = {
1442 .fd = uap->fd,
1443 .changelist = uap->changelist,
1444 .nchanges = uap->nchanges,
1445 .eventlist = uap->eventlist,
1446 .nevents = uap->nevents,
1447 .timeout = uap->timeout,
1448 };
1449
1450 return (kern_kevent_generic(td, &gk_args, &k_ops, "freebsd11_kevent"));
1451 }
1452 #endif
1453
1454 int
kern_kevent(struct thread * td,int fd,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout)1455 kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
1456 struct kevent_copyops *k_ops, const struct timespec *timeout)
1457 {
1458 cap_rights_t rights;
1459 struct file *fp;
1460 int error;
1461
1462 cap_rights_init_zero(&rights);
1463 if (nchanges > 0)
1464 cap_rights_set_one(&rights, CAP_KQUEUE_CHANGE);
1465 if (nevents > 0)
1466 cap_rights_set_one(&rights, CAP_KQUEUE_EVENT);
1467 error = fget(td, fd, &rights, &fp);
1468 if (error != 0)
1469 return (error);
1470
1471 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout);
1472 fdrop(fp, td);
1473
1474 return (error);
1475 }
1476
1477 static int
kqueue_kevent(struct kqueue * kq,struct thread * td,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout)1478 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents,
1479 struct kevent_copyops *k_ops, const struct timespec *timeout)
1480 {
1481 struct kevent keva[KQ_NEVENTS];
1482 struct kevent *kevp, *changes;
1483 int i, n, nerrors, error;
1484
1485 if (nchanges < 0)
1486 return (EINVAL);
1487
1488 nerrors = 0;
1489 while (nchanges > 0) {
1490 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
1491 error = k_ops->k_copyin(k_ops->arg, keva, n);
1492 if (error)
1493 return (error);
1494 changes = keva;
1495 for (i = 0; i < n; i++) {
1496 kevp = &changes[i];
1497 if (!kevp->filter)
1498 continue;
1499 kevp->flags &= ~EV_SYSFLAGS;
1500 error = kqueue_register(kq, kevp, td, M_WAITOK);
1501 if (error || (kevp->flags & EV_RECEIPT)) {
1502 if (nevents == 0)
1503 return (error);
1504 kevp->flags = EV_ERROR;
1505 kevp->data = error;
1506 (void)k_ops->k_copyout(k_ops->arg, kevp, 1);
1507 nevents--;
1508 nerrors++;
1509 }
1510 }
1511 nchanges -= n;
1512 }
1513 if (nerrors) {
1514 td->td_retval[0] = nerrors;
1515 return (0);
1516 }
1517
1518 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td));
1519 }
1520
1521 int
kern_kevent_fp(struct thread * td,struct file * fp,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout)1522 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents,
1523 struct kevent_copyops *k_ops, const struct timespec *timeout)
1524 {
1525 struct kqueue *kq;
1526 int error;
1527
1528 error = kqueue_acquire(fp, &kq);
1529 if (error != 0)
1530 return (error);
1531 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout);
1532 kqueue_release(kq, 0);
1533 return (error);
1534 }
1535
1536 /*
1537 * Performs a kevent() call on a temporarily created kqueue. This can be
1538 * used to perform one-shot polling, similar to poll() and select().
1539 */
1540 int
kern_kevent_anonymous(struct thread * td,int nevents,struct kevent_copyops * k_ops)1541 kern_kevent_anonymous(struct thread *td, int nevents,
1542 struct kevent_copyops *k_ops)
1543 {
1544 struct kqueue kq = {};
1545 int error;
1546
1547 kqueue_init(&kq, false);
1548 kq.kq_refcnt = 1;
1549 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL);
1550 kqueue_drain(&kq, td);
1551 kqueue_destroy(&kq);
1552 return (error);
1553 }
1554
1555 int
kqueue_add_filteropts(int filt,const struct filterops * filtops)1556 kqueue_add_filteropts(int filt, const struct filterops *filtops)
1557 {
1558 int error;
1559
1560 error = 0;
1561 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
1562 printf(
1563 "trying to add a filterop that is out of range: %d is beyond %d\n",
1564 ~filt, EVFILT_SYSCOUNT);
1565 return EINVAL;
1566 }
1567 mtx_lock(&filterops_lock);
1568 if (sysfilt_ops[~filt].for_fop != &null_filtops &&
1569 sysfilt_ops[~filt].for_fop != NULL)
1570 error = EEXIST;
1571 else {
1572 sysfilt_ops[~filt].for_fop = filtops;
1573 sysfilt_ops[~filt].for_refcnt = 0;
1574 }
1575 mtx_unlock(&filterops_lock);
1576
1577 return (error);
1578 }
1579
1580 int
kqueue_del_filteropts(int filt)1581 kqueue_del_filteropts(int filt)
1582 {
1583 int error;
1584
1585 error = 0;
1586 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1587 return EINVAL;
1588
1589 mtx_lock(&filterops_lock);
1590 if (sysfilt_ops[~filt].for_fop == &null_filtops ||
1591 sysfilt_ops[~filt].for_fop == NULL)
1592 error = EINVAL;
1593 else if (sysfilt_ops[~filt].for_refcnt != 0)
1594 error = EBUSY;
1595 else {
1596 sysfilt_ops[~filt].for_fop = &null_filtops;
1597 sysfilt_ops[~filt].for_refcnt = 0;
1598 }
1599 mtx_unlock(&filterops_lock);
1600
1601 return error;
1602 }
1603
1604 static const struct filterops *
kqueue_fo_find(int filt)1605 kqueue_fo_find(int filt)
1606 {
1607
1608 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1609 return NULL;
1610
1611 if (sysfilt_ops[~filt].for_nolock)
1612 return sysfilt_ops[~filt].for_fop;
1613
1614 mtx_lock(&filterops_lock);
1615 sysfilt_ops[~filt].for_refcnt++;
1616 if (sysfilt_ops[~filt].for_fop == NULL)
1617 sysfilt_ops[~filt].for_fop = &null_filtops;
1618 mtx_unlock(&filterops_lock);
1619
1620 return sysfilt_ops[~filt].for_fop;
1621 }
1622
1623 static void
kqueue_fo_release(int filt)1624 kqueue_fo_release(int filt)
1625 {
1626
1627 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1628 return;
1629
1630 if (sysfilt_ops[~filt].for_nolock)
1631 return;
1632
1633 mtx_lock(&filterops_lock);
1634 KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
1635 ("filter object %d refcount not valid on release", filt));
1636 sysfilt_ops[~filt].for_refcnt--;
1637 mtx_unlock(&filterops_lock);
1638 }
1639
1640 /*
1641 * A ref to kq (obtained via kqueue_acquire) must be held.
1642 */
1643 static int
kqueue_register(struct kqueue * kq,struct kevent * kev,struct thread * td,int mflag)1644 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td,
1645 int mflag)
1646 {
1647 const struct filterops *fops;
1648 struct file *fp;
1649 struct knote *kn, *tkn;
1650 struct knlist *knl;
1651 int error, filt, event;
1652 int haskqglobal, filedesc_unlock;
1653
1654 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE))
1655 return (EINVAL);
1656
1657 fp = NULL;
1658 kn = NULL;
1659 knl = NULL;
1660 error = 0;
1661 haskqglobal = 0;
1662 filedesc_unlock = 0;
1663
1664 filt = kev->filter;
1665 fops = kqueue_fo_find(filt);
1666 if (fops == NULL)
1667 return EINVAL;
1668
1669 if (kev->flags & EV_ADD) {
1670 /* Reject an invalid flag pair early */
1671 if (kev->flags & EV_KEEPUDATA) {
1672 tkn = NULL;
1673 error = EINVAL;
1674 goto done;
1675 }
1676
1677 /*
1678 * Prevent waiting with locks. Non-sleepable
1679 * allocation failures are handled in the loop, only
1680 * if the spare knote appears to be actually required.
1681 */
1682 tkn = knote_alloc(mflag);
1683 } else {
1684 tkn = NULL;
1685 }
1686
1687 findkn:
1688 if (fops->f_isfd) {
1689 KASSERT(td != NULL, ("td is NULL"));
1690 if (kev->ident > INT_MAX)
1691 error = EBADF;
1692 else
1693 error = fget(td, kev->ident, &cap_event_rights, &fp);
1694 if (error)
1695 goto done;
1696
1697 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
1698 kev->ident, M_NOWAIT) != 0) {
1699 /* try again */
1700 fdrop(fp, td);
1701 fp = NULL;
1702 error = kqueue_expand(kq, fops, kev->ident, mflag);
1703 if (error)
1704 goto done;
1705 goto findkn;
1706 }
1707
1708 if (fp->f_type == DTYPE_KQUEUE) {
1709 /*
1710 * If we add some intelligence about what we are doing,
1711 * we should be able to support events on ourselves.
1712 * We need to know when we are doing this to prevent
1713 * getting both the knlist lock and the kq lock since
1714 * they are the same thing.
1715 */
1716 if (fp->f_data == kq) {
1717 error = EINVAL;
1718 goto done;
1719 }
1720
1721 /*
1722 * Pre-lock the filedesc before the global
1723 * lock mutex, see the comment in
1724 * kqueue_close().
1725 */
1726 FILEDESC_XLOCK(td->td_proc->p_fd);
1727 filedesc_unlock = 1;
1728 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1729 }
1730
1731 KQ_LOCK(kq);
1732 if (kev->ident < kq->kq_knlistsize) {
1733 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
1734 if (kev->filter == kn->kn_filter)
1735 break;
1736 }
1737 } else {
1738 if ((kev->flags & EV_ADD) == EV_ADD) {
1739 error = kqueue_expand(kq, fops, kev->ident, mflag);
1740 if (error != 0)
1741 goto done;
1742 }
1743
1744 KQ_LOCK(kq);
1745
1746 /*
1747 * If possible, find an existing knote to use for this kevent.
1748 */
1749 if (kev->filter == EVFILT_PROC &&
1750 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) {
1751 /* This is an internal creation of a process tracking
1752 * note. Don't attempt to coalesce this with an
1753 * existing note.
1754 */
1755 ;
1756 } else if (kq->kq_knhashmask != 0) {
1757 struct klist *list;
1758
1759 list = &kq->kq_knhash[
1760 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
1761 SLIST_FOREACH(kn, list, kn_link)
1762 if (kev->ident == kn->kn_id &&
1763 kev->filter == kn->kn_filter)
1764 break;
1765 }
1766 }
1767
1768 /* knote is in the process of changing, wait for it to stabilize. */
1769 if (kn != NULL && kn_in_flux(kn)) {
1770 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1771 if (filedesc_unlock) {
1772 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1773 filedesc_unlock = 0;
1774 }
1775 kq->kq_state |= KQ_FLUXWAIT;
1776 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
1777 if (fp != NULL) {
1778 fdrop(fp, td);
1779 fp = NULL;
1780 }
1781 goto findkn;
1782 }
1783
1784 /*
1785 * kn now contains the matching knote, or NULL if no match
1786 */
1787 if (kn == NULL) {
1788 if (kev->flags & EV_ADD) {
1789 kn = tkn;
1790 tkn = NULL;
1791 if (kn == NULL) {
1792 KQ_UNLOCK(kq);
1793 error = ENOMEM;
1794 goto done;
1795 }
1796 kn->kn_fp = fp;
1797 kn->kn_kq = kq;
1798 kn->kn_fop = fops;
1799 /*
1800 * apply reference counts to knote structure, and
1801 * do not release it at the end of this routine.
1802 */
1803 fops = NULL;
1804 fp = NULL;
1805
1806 kn->kn_sfflags = kev->fflags;
1807 kn->kn_sdata = kev->data;
1808 kev->fflags = 0;
1809 kev->data = 0;
1810 kn->kn_kevent = *kev;
1811 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
1812 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT);
1813 kn->kn_status = KN_DETACHED;
1814 if ((kev->flags & EV_DISABLE) != 0)
1815 kn->kn_status |= KN_DISABLED;
1816 kn_enter_flux(kn);
1817
1818 error = knote_attach(kn, kq);
1819 KQ_UNLOCK(kq);
1820 if (error != 0) {
1821 tkn = kn;
1822 goto done;
1823 }
1824
1825 if ((error = kn->kn_fop->f_attach(kn)) != 0) {
1826 knote_drop_detached(kn, td);
1827 goto done;
1828 }
1829 knl = kn_list_lock(kn);
1830 goto done_ev_add;
1831 } else {
1832 /* No matching knote and the EV_ADD flag is not set. */
1833 KQ_UNLOCK(kq);
1834 error = ENOENT;
1835 goto done;
1836 }
1837 }
1838
1839 if (kev->flags & EV_DELETE) {
1840 kn_enter_flux(kn);
1841 KQ_UNLOCK(kq);
1842 knote_drop(kn, td);
1843 goto done;
1844 }
1845
1846 if (kev->flags & EV_FORCEONESHOT) {
1847 kn->kn_flags |= EV_ONESHOT;
1848 KNOTE_ACTIVATE(kn, 1);
1849 }
1850
1851 if ((kev->flags & EV_ENABLE) != 0)
1852 kn->kn_status &= ~KN_DISABLED;
1853 else if ((kev->flags & EV_DISABLE) != 0)
1854 kn->kn_status |= KN_DISABLED;
1855
1856 /*
1857 * The user may change some filter values after the initial EV_ADD,
1858 * but doing so will not reset any filter which has already been
1859 * triggered.
1860 */
1861 kn->kn_status |= KN_SCAN;
1862 kn_enter_flux(kn);
1863 KQ_UNLOCK(kq);
1864 knl = kn_list_lock(kn);
1865 if ((kev->flags & EV_KEEPUDATA) == 0)
1866 kn->kn_kevent.udata = kev->udata;
1867 if (!fops->f_isfd && fops->f_touch != NULL) {
1868 fops->f_touch(kn, kev, EVENT_REGISTER);
1869 } else {
1870 kn->kn_sfflags = kev->fflags;
1871 kn->kn_sdata = kev->data;
1872 }
1873
1874 done_ev_add:
1875 /*
1876 * We can get here with kn->kn_knlist == NULL. This can happen when
1877 * the initial attach event decides that the event is "completed"
1878 * already, e.g., filt_procattach() is called on a zombie process. It
1879 * will call filt_proc() which will remove it from the list, and NULL
1880 * kn_knlist.
1881 *
1882 * KN_DISABLED will be stable while the knote is in flux, so the
1883 * unlocked read will not race with an update.
1884 */
1885 if ((kn->kn_status & KN_DISABLED) == 0)
1886 event = kn->kn_fop->f_event(kn, 0);
1887 else
1888 event = 0;
1889
1890 KQ_LOCK(kq);
1891 if (event)
1892 kn->kn_status |= KN_ACTIVE;
1893 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) ==
1894 KN_ACTIVE)
1895 knote_enqueue(kn);
1896 kn->kn_status &= ~KN_SCAN;
1897 kn_leave_flux(kn);
1898 kn_list_unlock(knl);
1899 KQ_UNLOCK_FLUX(kq);
1900
1901 done:
1902 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1903 if (filedesc_unlock)
1904 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1905 if (fp != NULL)
1906 fdrop(fp, td);
1907 knote_free(tkn);
1908 if (fops != NULL)
1909 kqueue_fo_release(filt);
1910 return (error);
1911 }
1912
1913 static int
kqueue_acquire_ref(struct kqueue * kq)1914 kqueue_acquire_ref(struct kqueue *kq)
1915 {
1916 KQ_LOCK(kq);
1917 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
1918 KQ_UNLOCK(kq);
1919 return (EBADF);
1920 }
1921 kq->kq_refcnt++;
1922 KQ_UNLOCK(kq);
1923 return (0);
1924 }
1925
1926 static int
kqueue_acquire(struct file * fp,struct kqueue ** kqp)1927 kqueue_acquire(struct file *fp, struct kqueue **kqp)
1928 {
1929 struct kqueue *kq;
1930 int error;
1931
1932 kq = fp->f_data;
1933 if (fp->f_type != DTYPE_KQUEUE || kq == NULL)
1934 return (EINVAL);
1935 error = kqueue_acquire_ref(kq);
1936 if (error == 0)
1937 *kqp = kq;
1938 return (error);
1939 }
1940
1941 static void
kqueue_release(struct kqueue * kq,int locked)1942 kqueue_release(struct kqueue *kq, int locked)
1943 {
1944 if (locked)
1945 KQ_OWNED(kq);
1946 else
1947 KQ_LOCK(kq);
1948 kq->kq_refcnt--;
1949 if (kq->kq_refcnt == 1)
1950 wakeup(&kq->kq_refcnt);
1951 if (!locked)
1952 KQ_UNLOCK(kq);
1953 }
1954
1955 static void
ast_kqueue(struct thread * td,int tda __unused)1956 ast_kqueue(struct thread *td, int tda __unused)
1957 {
1958 taskqueue_quiesce(taskqueue_kqueue_ctx);
1959 }
1960
1961 static void
kqueue_schedtask(struct kqueue * kq)1962 kqueue_schedtask(struct kqueue *kq)
1963 {
1964 KQ_OWNED(kq);
1965 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
1966 ("scheduling kqueue task while draining"));
1967
1968 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
1969 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task);
1970 kq->kq_state |= KQ_TASKSCHED;
1971 ast_sched(curthread, TDA_KQUEUE);
1972 }
1973 }
1974
1975 /*
1976 * Expand the kq to make sure we have storage for fops/ident pair.
1977 *
1978 * Return 0 on success (or no work necessary), return errno on failure.
1979 */
1980 static int
kqueue_expand(struct kqueue * kq,const struct filterops * fops,uintptr_t ident,int mflag)1981 kqueue_expand(struct kqueue *kq, const struct filterops *fops, uintptr_t ident,
1982 int mflag)
1983 {
1984 struct klist *list, *tmp_knhash, *to_free;
1985 u_long tmp_knhashmask;
1986 int error, fd, size;
1987
1988 KQ_NOTOWNED(kq);
1989
1990 error = 0;
1991 to_free = NULL;
1992 if (fops->f_isfd) {
1993 fd = ident;
1994 if (kq->kq_knlistsize <= fd) {
1995 size = kq->kq_knlistsize;
1996 while (size <= fd)
1997 size += KQEXTENT;
1998 list = malloc(size * sizeof(*list), M_KQUEUE, mflag);
1999 if (list == NULL)
2000 return ENOMEM;
2001 KQ_LOCK(kq);
2002 if ((kq->kq_state & KQ_CLOSING) != 0) {
2003 to_free = list;
2004 error = EBADF;
2005 } else if (kq->kq_knlistsize > fd) {
2006 to_free = list;
2007 } else {
2008 if (kq->kq_knlist != NULL) {
2009 bcopy(kq->kq_knlist, list,
2010 kq->kq_knlistsize * sizeof(*list));
2011 to_free = kq->kq_knlist;
2012 kq->kq_knlist = NULL;
2013 }
2014 bzero((caddr_t)list +
2015 kq->kq_knlistsize * sizeof(*list),
2016 (size - kq->kq_knlistsize) * sizeof(*list));
2017 kq->kq_knlistsize = size;
2018 kq->kq_knlist = list;
2019 }
2020 KQ_UNLOCK(kq);
2021 }
2022 } else {
2023 if (kq->kq_knhashmask == 0) {
2024 tmp_knhash = hashinit_flags(KN_HASHSIZE, M_KQUEUE,
2025 &tmp_knhashmask, (mflag & M_WAITOK) != 0 ?
2026 HASH_WAITOK : HASH_NOWAIT);
2027 if (tmp_knhash == NULL)
2028 return (ENOMEM);
2029 KQ_LOCK(kq);
2030 if ((kq->kq_state & KQ_CLOSING) != 0) {
2031 to_free = tmp_knhash;
2032 error = EBADF;
2033 } else if (kq->kq_knhashmask == 0) {
2034 kq->kq_knhash = tmp_knhash;
2035 kq->kq_knhashmask = tmp_knhashmask;
2036 } else {
2037 to_free = tmp_knhash;
2038 }
2039 KQ_UNLOCK(kq);
2040 }
2041 }
2042 free(to_free, M_KQUEUE);
2043
2044 KQ_NOTOWNED(kq);
2045 return (error);
2046 }
2047
2048 static void
kqueue_task(void * arg,int pending)2049 kqueue_task(void *arg, int pending)
2050 {
2051 struct kqueue *kq;
2052 int haskqglobal;
2053
2054 haskqglobal = 0;
2055 kq = arg;
2056
2057 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
2058 KQ_LOCK(kq);
2059
2060 KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
2061
2062 kq->kq_state &= ~KQ_TASKSCHED;
2063 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
2064 wakeup(&kq->kq_state);
2065 }
2066 KQ_UNLOCK(kq);
2067 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
2068 }
2069
2070 /*
2071 * Scan, update kn_data (if not ONESHOT), and copyout triggered events.
2072 * We treat KN_MARKER knotes as if they are in flux.
2073 */
2074 static int
kqueue_scan(struct kqueue * kq,int maxevents,struct kevent_copyops * k_ops,const struct timespec * tsp,struct kevent * keva,struct thread * td)2075 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
2076 const struct timespec *tsp, struct kevent *keva, struct thread *td)
2077 {
2078 struct kevent *kevp;
2079 struct knote *kn, *marker;
2080 struct knlist *knl;
2081 sbintime_t asbt, rsbt;
2082 int count, error, haskqglobal, influx, nkev, touch;
2083
2084 count = maxevents;
2085 nkev = 0;
2086 error = 0;
2087 haskqglobal = 0;
2088
2089 if (maxevents == 0)
2090 goto done_nl;
2091 if (maxevents < 0) {
2092 error = EINVAL;
2093 goto done_nl;
2094 }
2095
2096 rsbt = 0;
2097 if (tsp != NULL) {
2098 if (!timespecvalid_interval(tsp)) {
2099 error = EINVAL;
2100 goto done_nl;
2101 }
2102 if (timespecisset(tsp)) {
2103 if (tsp->tv_sec <= INT32_MAX) {
2104 rsbt = tstosbt(*tsp);
2105 if (TIMESEL(&asbt, rsbt))
2106 asbt += tc_tick_sbt;
2107 if (asbt <= SBT_MAX - rsbt)
2108 asbt += rsbt;
2109 else
2110 asbt = 0;
2111 rsbt >>= tc_precexp;
2112 } else
2113 asbt = 0;
2114 } else
2115 asbt = -1;
2116 } else
2117 asbt = 0;
2118 marker = knote_alloc(M_WAITOK);
2119 marker->kn_status = KN_MARKER;
2120 KQ_LOCK(kq);
2121
2122 retry:
2123 kevp = keva;
2124 if (kq->kq_count == 0) {
2125 if (asbt == -1) {
2126 error = EWOULDBLOCK;
2127 } else {
2128 kq->kq_state |= KQ_SLEEP;
2129 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH,
2130 "kqread", asbt, rsbt, C_ABSOLUTE);
2131 }
2132 if (error == 0)
2133 goto retry;
2134 /* don't restart after signals... */
2135 if (error == ERESTART)
2136 error = EINTR;
2137 else if (error == EWOULDBLOCK)
2138 error = 0;
2139 goto done;
2140 }
2141
2142 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
2143 influx = 0;
2144 while (count) {
2145 KQ_OWNED(kq);
2146 kn = TAILQ_FIRST(&kq->kq_head);
2147
2148 if ((kn->kn_status == KN_MARKER && kn != marker) ||
2149 kn_in_flux(kn)) {
2150 if (influx) {
2151 influx = 0;
2152 KQ_FLUX_WAKEUP(kq);
2153 }
2154 kq->kq_state |= KQ_FLUXWAIT;
2155 error = msleep(kq, &kq->kq_lock, PSOCK,
2156 "kqflxwt", 0);
2157 continue;
2158 }
2159
2160 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
2161 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
2162 kn->kn_status &= ~KN_QUEUED;
2163 kq->kq_count--;
2164 continue;
2165 }
2166 if (kn == marker) {
2167 KQ_FLUX_WAKEUP(kq);
2168 if (count == maxevents)
2169 goto retry;
2170 goto done;
2171 }
2172 KASSERT(!kn_in_flux(kn),
2173 ("knote %p is unexpectedly in flux", kn));
2174
2175 if ((kn->kn_flags & EV_DROP) == EV_DROP) {
2176 kn->kn_status &= ~KN_QUEUED;
2177 kn_enter_flux(kn);
2178 kq->kq_count--;
2179 KQ_UNLOCK(kq);
2180 /*
2181 * We don't need to lock the list since we've
2182 * marked it as in flux.
2183 */
2184 knote_drop(kn, td);
2185 KQ_LOCK(kq);
2186 continue;
2187 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
2188 kn->kn_status &= ~KN_QUEUED;
2189 kn_enter_flux(kn);
2190 kq->kq_count--;
2191 KQ_UNLOCK(kq);
2192 /*
2193 * We don't need to lock the list since we've
2194 * marked the knote as being in flux.
2195 */
2196 *kevp = kn->kn_kevent;
2197 knote_drop(kn, td);
2198 KQ_LOCK(kq);
2199 kn = NULL;
2200 } else {
2201 kn->kn_status |= KN_SCAN;
2202 kn_enter_flux(kn);
2203 KQ_UNLOCK(kq);
2204 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
2205 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
2206 knl = kn_list_lock(kn);
2207 if (kn->kn_fop->f_event(kn, 0) == 0) {
2208 KQ_LOCK(kq);
2209 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
2210 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE |
2211 KN_SCAN);
2212 kn_leave_flux(kn);
2213 kq->kq_count--;
2214 kn_list_unlock(knl);
2215 influx = 1;
2216 continue;
2217 }
2218 touch = (!kn->kn_fop->f_isfd &&
2219 kn->kn_fop->f_touch != NULL);
2220 if (touch)
2221 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS);
2222 else
2223 *kevp = kn->kn_kevent;
2224 KQ_LOCK(kq);
2225 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
2226 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
2227 /*
2228 * Manually clear knotes who weren't
2229 * 'touch'ed.
2230 */
2231 if (touch == 0 && kn->kn_flags & EV_CLEAR) {
2232 kn->kn_data = 0;
2233 kn->kn_fflags = 0;
2234 }
2235 if (kn->kn_flags & EV_DISPATCH)
2236 kn->kn_status |= KN_DISABLED;
2237 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
2238 kq->kq_count--;
2239 } else
2240 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
2241
2242 kn->kn_status &= ~KN_SCAN;
2243 kn_leave_flux(kn);
2244 kn_list_unlock(knl);
2245 influx = 1;
2246 }
2247
2248 /* we are returning a copy to the user */
2249 kevp++;
2250 nkev++;
2251 count--;
2252
2253 if (nkev == KQ_NEVENTS) {
2254 influx = 0;
2255 KQ_UNLOCK_FLUX(kq);
2256 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
2257 nkev = 0;
2258 kevp = keva;
2259 KQ_LOCK(kq);
2260 if (error)
2261 break;
2262 }
2263 }
2264 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
2265 done:
2266 KQ_OWNED(kq);
2267 KQ_UNLOCK_FLUX(kq);
2268 knote_free(marker);
2269 done_nl:
2270 KQ_NOTOWNED(kq);
2271 if (nkev != 0)
2272 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
2273 td->td_retval[0] = maxevents - count;
2274 return (error);
2275 }
2276
2277 /*ARGSUSED*/
2278 static int
kqueue_ioctl(struct file * fp,u_long cmd,void * data,struct ucred * active_cred,struct thread * td)2279 kqueue_ioctl(struct file *fp, u_long cmd, void *data,
2280 struct ucred *active_cred, struct thread *td)
2281 {
2282 /*
2283 * Enabling sigio causes two major problems:
2284 * 1) infinite recursion:
2285 * Synopsys: kevent is being used to track signals and have FIOASYNC
2286 * set. On receipt of a signal this will cause a kqueue to recurse
2287 * into itself over and over. Sending the sigio causes the kqueue
2288 * to become ready, which in turn posts sigio again, forever.
2289 * Solution: this can be solved by setting a flag in the kqueue that
2290 * we have a SIGIO in progress.
2291 * 2) locking problems:
2292 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
2293 * us above the proc and pgrp locks.
2294 * Solution: Post a signal using an async mechanism, being sure to
2295 * record a generation count in the delivery so that we do not deliver
2296 * a signal to the wrong process.
2297 *
2298 * Note, these two mechanisms are somewhat mutually exclusive!
2299 */
2300 #if 0
2301 struct kqueue *kq;
2302
2303 kq = fp->f_data;
2304 switch (cmd) {
2305 case FIOASYNC:
2306 if (*(int *)data) {
2307 kq->kq_state |= KQ_ASYNC;
2308 } else {
2309 kq->kq_state &= ~KQ_ASYNC;
2310 }
2311 return (0);
2312
2313 case FIOSETOWN:
2314 return (fsetown(*(int *)data, &kq->kq_sigio));
2315
2316 case FIOGETOWN:
2317 *(int *)data = fgetown(&kq->kq_sigio);
2318 return (0);
2319 }
2320 #endif
2321
2322 return (ENOTTY);
2323 }
2324
2325 /*ARGSUSED*/
2326 static int
kqueue_poll(struct file * fp,int events,struct ucred * active_cred,struct thread * td)2327 kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
2328 struct thread *td)
2329 {
2330 struct kqueue *kq;
2331 int revents = 0;
2332 int error;
2333
2334 if ((error = kqueue_acquire(fp, &kq)))
2335 return POLLERR;
2336
2337 KQ_LOCK(kq);
2338 if (events & (POLLIN | POLLRDNORM)) {
2339 if (kq->kq_count) {
2340 revents |= events & (POLLIN | POLLRDNORM);
2341 } else {
2342 selrecord(td, &kq->kq_sel);
2343 if (SEL_WAITING(&kq->kq_sel))
2344 kq->kq_state |= KQ_SEL;
2345 }
2346 }
2347 kqueue_release(kq, 1);
2348 KQ_UNLOCK(kq);
2349 return (revents);
2350 }
2351
2352 /*ARGSUSED*/
2353 static int
kqueue_stat(struct file * fp,struct stat * st,struct ucred * active_cred)2354 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred)
2355 {
2356
2357 bzero((void *)st, sizeof *st);
2358 /*
2359 * We no longer return kq_count because the unlocked value is useless.
2360 * If you spent all this time getting the count, why not spend your
2361 * syscall better by calling kevent?
2362 *
2363 * XXX - This is needed for libc_r.
2364 */
2365 st->st_mode = S_IFIFO;
2366 return (0);
2367 }
2368
2369 static void
kqueue_drain(struct kqueue * kq,struct thread * td)2370 kqueue_drain(struct kqueue *kq, struct thread *td)
2371 {
2372 struct knote *kn;
2373 int i;
2374
2375 KQ_LOCK(kq);
2376
2377 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
2378 ("kqueue already closing"));
2379 kq->kq_state |= KQ_CLOSING;
2380 if (kq->kq_refcnt > 1)
2381 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
2382
2383 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
2384
2385 KASSERT(knlist_empty(&kq->kq_sel.si_note),
2386 ("kqueue's knlist not empty"));
2387
2388 for (i = 0; i < kq->kq_knlistsize; i++) {
2389 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
2390 if (kn_in_flux(kn)) {
2391 kq->kq_state |= KQ_FLUXWAIT;
2392 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
2393 continue;
2394 }
2395 kn_enter_flux(kn);
2396 KQ_UNLOCK(kq);
2397 knote_drop(kn, td);
2398 KQ_LOCK(kq);
2399 }
2400 }
2401 if (kq->kq_knhashmask != 0) {
2402 for (i = 0; i <= kq->kq_knhashmask; i++) {
2403 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
2404 if (kn_in_flux(kn)) {
2405 kq->kq_state |= KQ_FLUXWAIT;
2406 msleep(kq, &kq->kq_lock, PSOCK,
2407 "kqclo2", 0);
2408 continue;
2409 }
2410 kn_enter_flux(kn);
2411 KQ_UNLOCK(kq);
2412 knote_drop(kn, td);
2413 KQ_LOCK(kq);
2414 }
2415 }
2416 }
2417
2418 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
2419 kq->kq_state |= KQ_TASKDRAIN;
2420 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
2421 }
2422
2423 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
2424 selwakeuppri(&kq->kq_sel, PSOCK);
2425 if (!SEL_WAITING(&kq->kq_sel))
2426 kq->kq_state &= ~KQ_SEL;
2427 }
2428
2429 KQ_UNLOCK(kq);
2430 }
2431
2432 static void
kqueue_destroy(struct kqueue * kq)2433 kqueue_destroy(struct kqueue *kq)
2434 {
2435
2436 KASSERT(kq->kq_fdp == NULL,
2437 ("kqueue still attached to a file descriptor"));
2438 seldrain(&kq->kq_sel);
2439 knlist_destroy(&kq->kq_sel.si_note);
2440 mtx_destroy(&kq->kq_lock);
2441
2442 if (kq->kq_knhash != NULL)
2443 free(kq->kq_knhash, M_KQUEUE);
2444 if (kq->kq_knlist != NULL)
2445 free(kq->kq_knlist, M_KQUEUE);
2446
2447 funsetown(&kq->kq_sigio);
2448 }
2449
2450 /*ARGSUSED*/
2451 static int
kqueue_close(struct file * fp,struct thread * td)2452 kqueue_close(struct file *fp, struct thread *td)
2453 {
2454 struct kqueue *kq = fp->f_data;
2455 struct filedesc *fdp;
2456 int error;
2457 int filedesc_unlock;
2458
2459 if ((error = kqueue_acquire(fp, &kq)))
2460 return error;
2461 kqueue_drain(kq, td);
2462
2463 /*
2464 * We could be called due to the knote_drop() doing fdrop(),
2465 * called from kqueue_register(). In this case the global
2466 * lock is owned, and filedesc sx is locked before, to not
2467 * take the sleepable lock after non-sleepable.
2468 */
2469 fdp = kq->kq_fdp;
2470 kq->kq_fdp = NULL;
2471 if (!sx_xlocked(FILEDESC_LOCK(fdp))) {
2472 FILEDESC_XLOCK(fdp);
2473 filedesc_unlock = 1;
2474 } else
2475 filedesc_unlock = 0;
2476 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list);
2477 if (filedesc_unlock)
2478 FILEDESC_XUNLOCK(fdp);
2479
2480 kqueue_destroy(kq);
2481 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0);
2482 crfree(kq->kq_cred);
2483 free(kq, M_KQUEUE);
2484 fp->f_data = NULL;
2485
2486 return (0);
2487 }
2488
2489 static int
kqueue_fill_kinfo(struct file * fp,struct kinfo_file * kif,struct filedesc * fdp)2490 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
2491 {
2492 struct kqueue *kq = fp->f_data;
2493
2494 kif->kf_type = KF_TYPE_KQUEUE;
2495 kif->kf_un.kf_kqueue.kf_kqueue_addr = (uintptr_t)kq;
2496 kif->kf_un.kf_kqueue.kf_kqueue_count = kq->kq_count;
2497 kif->kf_un.kf_kqueue.kf_kqueue_state = kq->kq_state;
2498 return (0);
2499 }
2500
2501 static void
kqueue_wakeup(struct kqueue * kq)2502 kqueue_wakeup(struct kqueue *kq)
2503 {
2504 KQ_OWNED(kq);
2505
2506 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
2507 kq->kq_state &= ~KQ_SLEEP;
2508 wakeup(kq);
2509 }
2510 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
2511 selwakeuppri(&kq->kq_sel, PSOCK);
2512 if (!SEL_WAITING(&kq->kq_sel))
2513 kq->kq_state &= ~KQ_SEL;
2514 }
2515 if (!knlist_empty(&kq->kq_sel.si_note))
2516 kqueue_schedtask(kq);
2517 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
2518 pgsigio(&kq->kq_sigio, SIGIO, 0);
2519 }
2520 }
2521
2522 /*
2523 * Walk down a list of knotes, activating them if their event has triggered.
2524 *
2525 * There is a possibility to optimize in the case of one kq watching another.
2526 * Instead of scheduling a task to wake it up, you could pass enough state
2527 * down the chain to make up the parent kqueue. Make this code functional
2528 * first.
2529 */
2530 void
knote(struct knlist * list,long hint,int lockflags)2531 knote(struct knlist *list, long hint, int lockflags)
2532 {
2533 struct kqueue *kq;
2534 struct knote *kn, *tkn;
2535 int error;
2536
2537 if (list == NULL)
2538 return;
2539
2540 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
2541
2542 if ((lockflags & KNF_LISTLOCKED) == 0)
2543 list->kl_lock(list->kl_lockarg);
2544
2545 /*
2546 * If we unlock the list lock (and enter influx), we can
2547 * eliminate the kqueue scheduling, but this will introduce
2548 * four lock/unlock's for each knote to test. Also, marker
2549 * would be needed to keep iteration position, since filters
2550 * or other threads could remove events.
2551 */
2552 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) {
2553 kq = kn->kn_kq;
2554 KQ_LOCK(kq);
2555 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) {
2556 /*
2557 * Do not process the influx notes, except for
2558 * the influx coming from the kq unlock in the
2559 * kqueue_scan(). In the later case, we do
2560 * not interfere with the scan, since the code
2561 * fragment in kqueue_scan() locks the knlist,
2562 * and cannot proceed until we finished.
2563 */
2564 KQ_UNLOCK(kq);
2565 } else if ((lockflags & KNF_NOKQLOCK) != 0) {
2566 kn_enter_flux(kn);
2567 KQ_UNLOCK(kq);
2568 error = kn->kn_fop->f_event(kn, hint);
2569 KQ_LOCK(kq);
2570 kn_leave_flux(kn);
2571 if (error)
2572 KNOTE_ACTIVATE(kn, 1);
2573 KQ_UNLOCK_FLUX(kq);
2574 } else {
2575 if (kn->kn_fop->f_event(kn, hint))
2576 KNOTE_ACTIVATE(kn, 1);
2577 KQ_UNLOCK(kq);
2578 }
2579 }
2580 if ((lockflags & KNF_LISTLOCKED) == 0)
2581 list->kl_unlock(list->kl_lockarg);
2582 }
2583
2584 /*
2585 * add a knote to a knlist
2586 */
2587 void
knlist_add(struct knlist * knl,struct knote * kn,int islocked)2588 knlist_add(struct knlist *knl, struct knote *kn, int islocked)
2589 {
2590
2591 KNL_ASSERT_LOCK(knl, islocked);
2592 KQ_NOTOWNED(kn->kn_kq);
2593 KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn));
2594 KASSERT((kn->kn_status & KN_DETACHED) != 0,
2595 ("knote %p was not detached", kn));
2596 if (!islocked)
2597 knl->kl_lock(knl->kl_lockarg);
2598 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext);
2599 if (!islocked)
2600 knl->kl_unlock(knl->kl_lockarg);
2601 KQ_LOCK(kn->kn_kq);
2602 kn->kn_knlist = knl;
2603 kn->kn_status &= ~KN_DETACHED;
2604 KQ_UNLOCK(kn->kn_kq);
2605 }
2606
2607 static void
knlist_remove_kq(struct knlist * knl,struct knote * kn,int knlislocked,int kqislocked)2608 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked,
2609 int kqislocked)
2610 {
2611
2612 KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked"));
2613 KNL_ASSERT_LOCK(knl, knlislocked);
2614 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED);
2615 KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn));
2616 KASSERT((kn->kn_status & KN_DETACHED) == 0,
2617 ("knote %p was already detached", kn));
2618 if (!knlislocked)
2619 knl->kl_lock(knl->kl_lockarg);
2620 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
2621 kn->kn_knlist = NULL;
2622 if (!knlislocked)
2623 kn_list_unlock(knl);
2624 if (!kqislocked)
2625 KQ_LOCK(kn->kn_kq);
2626 kn->kn_status |= KN_DETACHED;
2627 if (!kqislocked)
2628 KQ_UNLOCK(kn->kn_kq);
2629 }
2630
2631 /*
2632 * remove knote from the specified knlist
2633 */
2634 void
knlist_remove(struct knlist * knl,struct knote * kn,int islocked)2635 knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
2636 {
2637
2638 knlist_remove_kq(knl, kn, islocked, 0);
2639 }
2640
2641 int
knlist_empty(struct knlist * knl)2642 knlist_empty(struct knlist *knl)
2643 {
2644
2645 KNL_ASSERT_LOCKED(knl);
2646 return (SLIST_EMPTY(&knl->kl_list));
2647 }
2648
2649 static struct mtx knlist_lock;
2650 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects",
2651 MTX_DEF);
2652 static void knlist_mtx_lock(void *arg);
2653 static void knlist_mtx_unlock(void *arg);
2654
2655 static void
knlist_mtx_lock(void * arg)2656 knlist_mtx_lock(void *arg)
2657 {
2658
2659 mtx_lock((struct mtx *)arg);
2660 }
2661
2662 static void
knlist_mtx_unlock(void * arg)2663 knlist_mtx_unlock(void *arg)
2664 {
2665
2666 mtx_unlock((struct mtx *)arg);
2667 }
2668
2669 static void
knlist_mtx_assert_lock(void * arg,int what)2670 knlist_mtx_assert_lock(void *arg, int what)
2671 {
2672
2673 if (what == LA_LOCKED)
2674 mtx_assert((struct mtx *)arg, MA_OWNED);
2675 else
2676 mtx_assert((struct mtx *)arg, MA_NOTOWNED);
2677 }
2678
2679 void
knlist_init(struct knlist * knl,void * lock,void (* kl_lock)(void *),void (* kl_unlock)(void *),void (* kl_assert_lock)(void *,int))2680 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
2681 void (*kl_unlock)(void *),
2682 void (*kl_assert_lock)(void *, int))
2683 {
2684
2685 if (lock == NULL)
2686 knl->kl_lockarg = &knlist_lock;
2687 else
2688 knl->kl_lockarg = lock;
2689
2690 if (kl_lock == NULL)
2691 knl->kl_lock = knlist_mtx_lock;
2692 else
2693 knl->kl_lock = kl_lock;
2694 if (kl_unlock == NULL)
2695 knl->kl_unlock = knlist_mtx_unlock;
2696 else
2697 knl->kl_unlock = kl_unlock;
2698 if (kl_assert_lock == NULL)
2699 knl->kl_assert_lock = knlist_mtx_assert_lock;
2700 else
2701 knl->kl_assert_lock = kl_assert_lock;
2702
2703 knl->kl_autodestroy = 0;
2704 SLIST_INIT(&knl->kl_list);
2705 }
2706
2707 void
knlist_init_mtx(struct knlist * knl,struct mtx * lock)2708 knlist_init_mtx(struct knlist *knl, struct mtx *lock)
2709 {
2710
2711 knlist_init(knl, lock, NULL, NULL, NULL);
2712 }
2713
2714 struct knlist *
knlist_alloc(struct mtx * lock)2715 knlist_alloc(struct mtx *lock)
2716 {
2717 struct knlist *knl;
2718
2719 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK);
2720 knlist_init_mtx(knl, lock);
2721 return (knl);
2722 }
2723
2724 void
knlist_destroy(struct knlist * knl)2725 knlist_destroy(struct knlist *knl)
2726 {
2727
2728 KASSERT(KNLIST_EMPTY(knl),
2729 ("destroying knlist %p with knotes on it", knl));
2730 }
2731
2732 void
knlist_detach(struct knlist * knl)2733 knlist_detach(struct knlist *knl)
2734 {
2735
2736 KNL_ASSERT_LOCKED(knl);
2737 knl->kl_autodestroy = 1;
2738 if (knlist_empty(knl)) {
2739 knlist_destroy(knl);
2740 free(knl, M_KQUEUE);
2741 }
2742 }
2743
2744 /*
2745 * Even if we are locked, we may need to drop the lock to allow any influx
2746 * knotes time to "settle".
2747 */
2748 void
knlist_cleardel(struct knlist * knl,struct thread * td,int islocked,int killkn)2749 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
2750 {
2751 struct knote *kn, *kn2;
2752 struct kqueue *kq;
2753
2754 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl));
2755 if (islocked)
2756 KNL_ASSERT_LOCKED(knl);
2757 else {
2758 KNL_ASSERT_UNLOCKED(knl);
2759 again: /* need to reacquire lock since we have dropped it */
2760 knl->kl_lock(knl->kl_lockarg);
2761 }
2762
2763 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
2764 kq = kn->kn_kq;
2765 KQ_LOCK(kq);
2766 if (kn_in_flux(kn)) {
2767 KQ_UNLOCK(kq);
2768 continue;
2769 }
2770 knlist_remove_kq(knl, kn, 1, 1);
2771 if (killkn) {
2772 kn_enter_flux(kn);
2773 KQ_UNLOCK(kq);
2774 knote_drop_detached(kn, td);
2775 } else {
2776 /* Make sure cleared knotes disappear soon */
2777 kn->kn_flags |= EV_EOF | EV_ONESHOT;
2778 KQ_UNLOCK(kq);
2779 }
2780 kq = NULL;
2781 }
2782
2783 if (!SLIST_EMPTY(&knl->kl_list)) {
2784 /* there are still in flux knotes remaining */
2785 kn = SLIST_FIRST(&knl->kl_list);
2786 kq = kn->kn_kq;
2787 KQ_LOCK(kq);
2788 KASSERT(kn_in_flux(kn), ("knote removed w/o list lock"));
2789 knl->kl_unlock(knl->kl_lockarg);
2790 kq->kq_state |= KQ_FLUXWAIT;
2791 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
2792 kq = NULL;
2793 goto again;
2794 }
2795
2796 if (islocked)
2797 KNL_ASSERT_LOCKED(knl);
2798 else {
2799 knl->kl_unlock(knl->kl_lockarg);
2800 KNL_ASSERT_UNLOCKED(knl);
2801 }
2802 }
2803
2804 /*
2805 * Remove all knotes referencing a specified fd must be called with FILEDESC
2806 * lock. This prevents a race where a new fd comes along and occupies the
2807 * entry and we attach a knote to the fd.
2808 */
2809 void
knote_fdclose(struct thread * td,int fd)2810 knote_fdclose(struct thread *td, int fd)
2811 {
2812 struct filedesc *fdp = td->td_proc->p_fd;
2813 struct kqueue *kq;
2814 struct knote *kn;
2815 int influx;
2816
2817 FILEDESC_XLOCK_ASSERT(fdp);
2818
2819 /*
2820 * We shouldn't have to worry about new kevents appearing on fd
2821 * since filedesc is locked.
2822 */
2823 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
2824 KQ_LOCK(kq);
2825
2826 again:
2827 influx = 0;
2828 while (kq->kq_knlistsize > fd &&
2829 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
2830 if (kn_in_flux(kn)) {
2831 /* someone else might be waiting on our knote */
2832 if (influx)
2833 wakeup(kq);
2834 kq->kq_state |= KQ_FLUXWAIT;
2835 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
2836 goto again;
2837 }
2838 kn_enter_flux(kn);
2839 KQ_UNLOCK(kq);
2840 influx = 1;
2841 knote_drop(kn, td);
2842 KQ_LOCK(kq);
2843 }
2844 KQ_UNLOCK_FLUX(kq);
2845 }
2846 }
2847
2848 static int
knote_attach(struct knote * kn,struct kqueue * kq)2849 knote_attach(struct knote *kn, struct kqueue *kq)
2850 {
2851 struct klist *list;
2852
2853 KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn));
2854 KQ_OWNED(kq);
2855
2856 if ((kq->kq_state & KQ_CLOSING) != 0)
2857 return (EBADF);
2858 if (kn->kn_fop->f_isfd) {
2859 if (kn->kn_id >= kq->kq_knlistsize)
2860 return (ENOMEM);
2861 list = &kq->kq_knlist[kn->kn_id];
2862 } else {
2863 if (kq->kq_knhash == NULL)
2864 return (ENOMEM);
2865 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2866 }
2867 SLIST_INSERT_HEAD(list, kn, kn_link);
2868 return (0);
2869 }
2870
2871 static void
knote_drop(struct knote * kn,struct thread * td)2872 knote_drop(struct knote *kn, struct thread *td)
2873 {
2874
2875 if ((kn->kn_status & KN_DETACHED) == 0)
2876 kn->kn_fop->f_detach(kn);
2877 knote_drop_detached(kn, td);
2878 }
2879
2880 static void
knote_drop_detached(struct knote * kn,struct thread * td)2881 knote_drop_detached(struct knote *kn, struct thread *td)
2882 {
2883 struct kqueue *kq;
2884 struct klist *list;
2885
2886 kq = kn->kn_kq;
2887
2888 KASSERT((kn->kn_status & KN_DETACHED) != 0,
2889 ("knote %p still attached", kn));
2890 KQ_NOTOWNED(kq);
2891
2892 KQ_LOCK(kq);
2893 for (;;) {
2894 KASSERT(kn->kn_influx >= 1,
2895 ("knote_drop called on %p with influx %d",
2896 kn, kn->kn_influx));
2897 if (kn->kn_influx == 1)
2898 break;
2899 kq->kq_state |= KQ_FLUXWAIT;
2900 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
2901 }
2902
2903 if (kn->kn_fop->f_isfd)
2904 list = &kq->kq_knlist[kn->kn_id];
2905 else
2906 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2907
2908 if (!SLIST_EMPTY(list))
2909 SLIST_REMOVE(list, kn, knote, kn_link);
2910 if (kn->kn_status & KN_QUEUED)
2911 knote_dequeue(kn);
2912 KQ_UNLOCK_FLUX(kq);
2913
2914 if (kn->kn_fop->f_isfd) {
2915 fdrop(kn->kn_fp, td);
2916 kn->kn_fp = NULL;
2917 }
2918 kqueue_fo_release(kn->kn_kevent.filter);
2919 kn->kn_fop = NULL;
2920 knote_free(kn);
2921 }
2922
2923 static void
knote_enqueue(struct knote * kn)2924 knote_enqueue(struct knote *kn)
2925 {
2926 struct kqueue *kq = kn->kn_kq;
2927
2928 KQ_OWNED(kn->kn_kq);
2929 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
2930
2931 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
2932 kn->kn_status |= KN_QUEUED;
2933 kq->kq_count++;
2934 kqueue_wakeup(kq);
2935 }
2936
2937 static void
knote_dequeue(struct knote * kn)2938 knote_dequeue(struct knote *kn)
2939 {
2940 struct kqueue *kq = kn->kn_kq;
2941
2942 KQ_OWNED(kn->kn_kq);
2943 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
2944
2945 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
2946 kn->kn_status &= ~KN_QUEUED;
2947 kq->kq_count--;
2948 }
2949
2950 static void
knote_init(void * dummy __unused)2951 knote_init(void *dummy __unused)
2952 {
2953
2954 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
2955 NULL, NULL, UMA_ALIGN_PTR, 0);
2956 ast_register(TDA_KQUEUE, ASTR_ASTF_REQUIRED, 0, ast_kqueue);
2957 prison0.pr_klist = knlist_alloc(&prison0.pr_mtx);
2958 }
2959 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
2960
2961 static struct knote *
knote_alloc(int mflag)2962 knote_alloc(int mflag)
2963 {
2964
2965 return (uma_zalloc(knote_zone, mflag | M_ZERO));
2966 }
2967
2968 static void
knote_free(struct knote * kn)2969 knote_free(struct knote *kn)
2970 {
2971
2972 uma_zfree(knote_zone, kn);
2973 }
2974
2975 /*
2976 * Register the kev w/ the kq specified by fd.
2977 */
2978 int
kqfd_register(int fd,struct kevent * kev,struct thread * td,int mflag)2979 kqfd_register(int fd, struct kevent *kev, struct thread *td, int mflag)
2980 {
2981 struct kqueue *kq;
2982 struct file *fp;
2983 cap_rights_t rights;
2984 int error;
2985
2986 error = fget(td, fd, cap_rights_init_one(&rights, CAP_KQUEUE_CHANGE),
2987 &fp);
2988 if (error != 0)
2989 return (error);
2990 if ((error = kqueue_acquire(fp, &kq)) != 0)
2991 goto noacquire;
2992
2993 error = kqueue_register(kq, kev, td, mflag);
2994 kqueue_release(kq, 0);
2995
2996 noacquire:
2997 fdrop(fp, td);
2998 return (error);
2999 }
3000
3001 static int
kqueue_fork_alloc(struct filedesc * fdp,struct file * fp,struct file ** fp1,struct thread * td)3002 kqueue_fork_alloc(struct filedesc *fdp, struct file *fp, struct file **fp1,
3003 struct thread *td)
3004 {
3005 struct kqueue *kq, *kq1;
3006 int error;
3007
3008 MPASS(fp->f_type == DTYPE_KQUEUE);
3009 kq = fp->f_data;
3010 if ((kq->kq_state & KQ_CPONFORK) == 0)
3011 return (EOPNOTSUPP);
3012 error = kqueue_acquire_ref(kq);
3013 if (error != 0)
3014 return (error);
3015 error = kern_kqueue_alloc(td, fdp, NULL, fp1, 0, NULL, true, &kq1);
3016 if (error == 0) {
3017 kq1->kq_forksrc = kq;
3018 (*fp1)->f_flag = fp->f_flag & (FREAD | FWRITE | FEXEC |
3019 O_CLOEXEC | O_CLOFORK);
3020 } else {
3021 kqueue_release(kq, 0);
3022 }
3023 return (error);
3024 }
3025
3026 static void
kqueue_fork_copy_knote(struct kqueue * kq1,struct knote * kn,struct proc * p1,struct filedesc * fdp)3027 kqueue_fork_copy_knote(struct kqueue *kq1, struct knote *kn, struct proc *p1,
3028 struct filedesc *fdp)
3029 {
3030 struct knote *kn1;
3031 const struct filterops *fop;
3032 int error;
3033
3034 fop = kn->kn_fop;
3035 if (fop->f_copy == NULL || (fop->f_isfd &&
3036 fdp->fd_files->fdt_ofiles[kn->kn_kevent.ident].fde_file == NULL))
3037 return;
3038 error = kqueue_expand(kq1, fop, kn->kn_kevent.ident, M_WAITOK);
3039 if (error != 0)
3040 return;
3041
3042 kn1 = knote_alloc(M_WAITOK);
3043 *kn1 = *kn;
3044 kn1->kn_status |= KN_DETACHED;
3045 kn1->kn_status &= ~KN_QUEUED;
3046 kn1->kn_kq = kq1;
3047 error = fop->f_copy(kn1, p1);
3048 if (error != 0) {
3049 knote_free(kn1);
3050 return;
3051 }
3052 (void)kqueue_fo_find(kn->kn_kevent.filter);
3053 if (fop->f_isfd && !fhold(kn1->kn_fp)) {
3054 fop->f_detach(kn1);
3055 kqueue_fo_release(kn->kn_kevent.filter);
3056 knote_free(kn1);
3057 return;
3058 }
3059 if (kn->kn_knlist != NULL)
3060 knlist_add(kn->kn_knlist, kn1, 0);
3061 KQ_LOCK(kq1);
3062 knote_attach(kn1, kq1);
3063 kn1->kn_influx = 0;
3064 if ((kn->kn_status & KN_QUEUED) != 0)
3065 knote_enqueue(kn1);
3066 KQ_UNLOCK(kq1);
3067 }
3068
3069 static void
kqueue_fork_copy_list(struct klist * knlist,struct knote * marker,struct kqueue * kq,struct kqueue * kq1,struct proc * p1,struct filedesc * fdp)3070 kqueue_fork_copy_list(struct klist *knlist, struct knote *marker,
3071 struct kqueue *kq, struct kqueue *kq1, struct proc *p1,
3072 struct filedesc *fdp)
3073 {
3074 struct knote *kn;
3075
3076 KQ_OWNED(kq);
3077 kn = SLIST_FIRST(knlist);
3078 while (kn != NULL) {
3079 if ((kn->kn_status & KN_DETACHED) != 0 ||
3080 (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0)) {
3081 kn = SLIST_NEXT(kn, kn_link);
3082 continue;
3083 }
3084 kn_enter_flux(kn);
3085 SLIST_INSERT_AFTER(kn, marker, kn_link);
3086 KQ_UNLOCK(kq);
3087 kqueue_fork_copy_knote(kq1, kn, p1, fdp);
3088 KQ_LOCK(kq);
3089 kn_leave_flux(kn);
3090 kn = SLIST_NEXT(marker, kn_link);
3091 /* XXXKIB switch kn_link to LIST? */
3092 SLIST_REMOVE(knlist, marker, knote, kn_link);
3093 }
3094 }
3095
3096 static int
kqueue_fork_copy(struct filedesc * fdp,struct file * fp,struct file * fp1,struct proc * p1,struct thread * td)3097 kqueue_fork_copy(struct filedesc *fdp, struct file *fp, struct file *fp1,
3098 struct proc *p1, struct thread *td)
3099 {
3100 struct kqueue *kq, *kq1;
3101 struct knote *marker;
3102 int error, i;
3103
3104 error = 0;
3105 MPASS(fp == NULL);
3106 MPASS(fp1->f_type == DTYPE_KQUEUE);
3107
3108 kq1 = fp1->f_data;
3109 kq = kq1->kq_forksrc;
3110 marker = knote_alloc(M_WAITOK);
3111 marker->kn_status = KN_MARKER;
3112
3113 KQ_LOCK(kq);
3114 for (i = 0; i < kq->kq_knlistsize; i++) {
3115 kqueue_fork_copy_list(&kq->kq_knlist[i], marker, kq, kq1,
3116 p1, fdp);
3117 }
3118 if (kq->kq_knhashmask != 0) {
3119 for (i = 0; i <= kq->kq_knhashmask; i++) {
3120 kqueue_fork_copy_list(&kq->kq_knhash[i], marker, kq,
3121 kq1, p1, fdp);
3122 }
3123 }
3124 kqueue_release(kq, 1);
3125 kq1->kq_forksrc = NULL;
3126 KQ_UNLOCK(kq);
3127
3128 knote_free(marker);
3129 return (error);
3130 }
3131
3132 static int
kqueue_fork(struct filedesc * fdp,struct file * fp,struct file ** fp1,struct proc * p1,struct thread * td)3133 kqueue_fork(struct filedesc *fdp, struct file *fp, struct file **fp1,
3134 struct proc *p1, struct thread *td)
3135 {
3136 if (*fp1 == NULL)
3137 return (kqueue_fork_alloc(fdp, fp, fp1, td));
3138 return (kqueue_fork_copy(fdp, fp, *fp1, p1, td));
3139 }
3140
3141 int
knote_triv_copy(struct knote * kn __unused,struct proc * p1 __unused)3142 knote_triv_copy(struct knote *kn __unused, struct proc *p1 __unused)
3143 {
3144 return (0);
3145 }
3146
3147 struct knote_status_export_bit {
3148 int kn_status_bit;
3149 int knt_status_bit;
3150 };
3151
3152 #define ST(name) \
3153 { .kn_status_bit = KN_##name, .knt_status_bit = KNOTE_STATUS_##name }
3154 static const struct knote_status_export_bit knote_status_export_bits[] = {
3155 ST(ACTIVE),
3156 ST(QUEUED),
3157 ST(DISABLED),
3158 ST(DETACHED),
3159 ST(KQUEUE),
3160 };
3161 #undef ST
3162
3163 static int
knote_status_export(int kn_status)3164 knote_status_export(int kn_status)
3165 {
3166 const struct knote_status_export_bit *b;
3167 unsigned i;
3168 int res;
3169
3170 res = 0;
3171 for (i = 0; i < nitems(knote_status_export_bits); i++) {
3172 b = &knote_status_export_bits[i];
3173 if ((kn_status & b->kn_status_bit) != 0)
3174 res |= b->knt_status_bit;
3175 }
3176 return (res);
3177 }
3178
3179 static int
kern_proc_kqueue_report_one(struct sbuf * s,struct proc * p,int kq_fd,struct kqueue * kq,struct knote * kn,bool compat32 __unused)3180 kern_proc_kqueue_report_one(struct sbuf *s, struct proc *p,
3181 int kq_fd, struct kqueue *kq, struct knote *kn, bool compat32 __unused)
3182 {
3183 struct kinfo_knote kin;
3184 #ifdef COMPAT_FREEBSD32
3185 struct kinfo_knote32 kin32;
3186 #endif
3187 int error;
3188
3189 if (kn->kn_status == KN_MARKER)
3190 return (0);
3191
3192 memset(&kin, 0, sizeof(kin));
3193 kin.knt_kq_fd = kq_fd;
3194 memcpy(&kin.knt_event, &kn->kn_kevent, sizeof(struct kevent));
3195 kin.knt_status = knote_status_export(kn->kn_status);
3196 kn_enter_flux(kn);
3197 KQ_UNLOCK_FLUX(kq);
3198 if (kn->kn_fop->f_userdump != NULL)
3199 (void)kn->kn_fop->f_userdump(p, kn, &kin);
3200 #ifdef COMPAT_FREEBSD32
3201 if (compat32) {
3202 freebsd32_kinfo_knote_to_32(&kin, &kin32);
3203 error = sbuf_bcat(s, &kin32, sizeof(kin32));
3204 } else
3205 #endif
3206 error = sbuf_bcat(s, &kin, sizeof(kin));
3207 KQ_LOCK(kq);
3208 kn_leave_flux(kn);
3209 return (error);
3210 }
3211
3212 static int
kern_proc_kqueue_report(struct sbuf * s,struct proc * p,int kq_fd,struct kqueue * kq,bool compat32)3213 kern_proc_kqueue_report(struct sbuf *s, struct proc *p, int kq_fd,
3214 struct kqueue *kq, bool compat32)
3215 {
3216 struct knote *kn;
3217 int error, i;
3218
3219 error = 0;
3220 KQ_LOCK(kq);
3221 for (i = 0; i < kq->kq_knlistsize; i++) {
3222 SLIST_FOREACH(kn, &kq->kq_knlist[i], kn_link) {
3223 error = kern_proc_kqueue_report_one(s, p, kq_fd,
3224 kq, kn, compat32);
3225 if (error != 0)
3226 goto out;
3227 }
3228 }
3229 if (kq->kq_knhashmask == 0)
3230 goto out;
3231 for (i = 0; i <= kq->kq_knhashmask; i++) {
3232 SLIST_FOREACH(kn, &kq->kq_knhash[i], kn_link) {
3233 error = kern_proc_kqueue_report_one(s, p, kq_fd,
3234 kq, kn, compat32);
3235 if (error != 0)
3236 goto out;
3237 }
3238 }
3239 out:
3240 KQ_UNLOCK_FLUX(kq);
3241 return (error);
3242 }
3243
3244 struct kern_proc_kqueues_out1_cb_args {
3245 struct sbuf *s;
3246 bool compat32;
3247 };
3248
3249 static int
kern_proc_kqueues_out1_cb(struct proc * p,int fd,struct file * fp,void * arg)3250 kern_proc_kqueues_out1_cb(struct proc *p, int fd, struct file *fp, void *arg)
3251 {
3252 struct kqueue *kq;
3253 struct kern_proc_kqueues_out1_cb_args *a;
3254
3255 if (fp->f_type != DTYPE_KQUEUE)
3256 return (0);
3257 a = arg;
3258 kq = fp->f_data;
3259 return (kern_proc_kqueue_report(a->s, p, fd, kq, a->compat32));
3260 }
3261
3262 static int
kern_proc_kqueues_out1(struct thread * td,struct proc * p,struct sbuf * s,bool compat32)3263 kern_proc_kqueues_out1(struct thread *td, struct proc *p, struct sbuf *s,
3264 bool compat32)
3265 {
3266 struct kern_proc_kqueues_out1_cb_args a;
3267
3268 a.s = s;
3269 a.compat32 = compat32;
3270 return (fget_remote_foreach(td, p, kern_proc_kqueues_out1_cb, &a));
3271 }
3272
3273 int
kern_proc_kqueues_out(struct proc * p,struct sbuf * sb,size_t maxlen,bool compat32)3274 kern_proc_kqueues_out(struct proc *p, struct sbuf *sb, size_t maxlen,
3275 bool compat32)
3276 {
3277 struct sbuf *s, sm;
3278 size_t sb_len;
3279 int error;
3280
3281 if (maxlen == -1 || maxlen == 0)
3282 sb_len = 128;
3283 else
3284 sb_len = maxlen;
3285 s = sbuf_new(&sm, NULL, sb_len, maxlen == -1 ? SBUF_AUTOEXTEND :
3286 SBUF_FIXEDLEN);
3287 error = kern_proc_kqueues_out1(curthread, p, s, compat32);
3288 sbuf_finish(s);
3289 if (error == 0) {
3290 sbuf_bcat(sb, sbuf_data(s), MIN(sbuf_len(s), maxlen == -1 ?
3291 SIZE_T_MAX : maxlen));
3292 }
3293 sbuf_delete(s);
3294 return (error);
3295 }
3296
3297 static int
sysctl_kern_proc_kqueue_one(struct thread * td,struct sbuf * s,struct proc * p,int kq_fd,bool compat32)3298 sysctl_kern_proc_kqueue_one(struct thread *td, struct sbuf *s, struct proc *p,
3299 int kq_fd, bool compat32)
3300 {
3301 struct file *fp;
3302 struct kqueue *kq;
3303 int error;
3304
3305 error = fget_remote(td, p, kq_fd, &fp);
3306 if (error == 0) {
3307 if (fp->f_type != DTYPE_KQUEUE) {
3308 error = EINVAL;
3309 } else {
3310 kq = fp->f_data;
3311 error = kern_proc_kqueue_report(s, p, kq_fd, kq,
3312 compat32);
3313 }
3314 fdrop(fp, td);
3315 }
3316 return (error);
3317 }
3318
3319 static int
sysctl_kern_proc_kqueue(SYSCTL_HANDLER_ARGS)3320 sysctl_kern_proc_kqueue(SYSCTL_HANDLER_ARGS)
3321 {
3322 struct thread *td;
3323 struct proc *p;
3324 struct sbuf *s, sm;
3325 int error, error1, *name;
3326 bool compat32;
3327
3328 name = (int *)arg1;
3329 if ((u_int)arg2 > 2 || (u_int)arg2 == 0)
3330 return (EINVAL);
3331
3332 error = pget((pid_t)name[0], PGET_HOLD | PGET_CANDEBUG, &p);
3333 if (error != 0)
3334 return (error);
3335
3336 td = curthread;
3337 #ifdef COMPAT_FREEBSD32
3338 compat32 = SV_CURPROC_FLAG(SV_ILP32);
3339 #else
3340 compat32 = false;
3341 #endif
3342
3343 s = sbuf_new_for_sysctl(&sm, NULL, 0, req);
3344 if (s == NULL) {
3345 error = ENOMEM;
3346 goto out;
3347 }
3348 sbuf_clear_flags(s, SBUF_INCLUDENUL);
3349
3350 if ((u_int)arg2 == 1) {
3351 error = kern_proc_kqueues_out1(td, p, s, compat32);
3352 } else {
3353 error = sysctl_kern_proc_kqueue_one(td, s, p,
3354 name[1] /* kq_fd */, compat32);
3355 }
3356
3357 error1 = sbuf_finish(s);
3358 if (error == 0)
3359 error = error1;
3360 sbuf_delete(s);
3361
3362 out:
3363 PRELE(p);
3364 return (error);
3365 }
3366
3367 static SYSCTL_NODE(_kern_proc, KERN_PROC_KQUEUE, kq,
3368 CTLFLAG_RD | CTLFLAG_MPSAFE,
3369 sysctl_kern_proc_kqueue, "KQueue events");
3370