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 "opt_ktrace.h"
32 #include "opt_kqueue.h"
33
34 #ifdef COMPAT_FREEBSD11
35 #define _WANT_FREEBSD11_KEVENT
36 #endif
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/capsicum.h>
41 #include <sys/kernel.h>
42 #include <sys/limits.h>
43 #include <sys/lock.h>
44 #include <sys/mutex.h>
45 #include <sys/proc.h>
46 #include <sys/malloc.h>
47 #include <sys/unistd.h>
48 #include <sys/file.h>
49 #include <sys/filedesc.h>
50 #include <sys/filio.h>
51 #include <sys/fcntl.h>
52 #include <sys/jail.h>
53 #include <sys/jaildesc.h>
54 #include <sys/kthread.h>
55 #include <sys/selinfo.h>
56 #include <sys/queue.h>
57 #include <sys/event.h>
58 #include <sys/eventvar.h>
59 #include <sys/poll.h>
60 #include <sys/protosw.h>
61 #include <sys/resourcevar.h>
62 #include <sys/sbuf.h>
63 #include <sys/sigio.h>
64 #include <sys/signalvar.h>
65 #include <sys/socket.h>
66 #include <sys/socketvar.h>
67 #include <sys/stat.h>
68 #include <sys/sysctl.h>
69 #include <sys/sysent.h>
70 #include <sys/sysproto.h>
71 #include <sys/syscallsubr.h>
72 #include <sys/taskqueue.h>
73 #include <sys/uio.h>
74 #include <sys/user.h>
75 #ifdef KTRACE
76 #include <sys/ktrace.h>
77 #endif
78 #include <machine/atomic.h>
79 #ifdef COMPAT_FREEBSD32
80 #include <compat/freebsd32/freebsd32.h>
81 #include <compat/freebsd32/freebsd32_util.h>
82 #endif
83
84 #include <vm/uma.h>
85
86 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
87
88 /*
89 * This lock is used if multiple kq locks are required. This possibly
90 * should be made into a per proc lock.
91 */
92 static struct mtx kq_global;
93 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF);
94 #define KQ_GLOBAL_LOCK(lck, haslck) do { \
95 if (!haslck) \
96 mtx_lock(lck); \
97 haslck = 1; \
98 } while (0)
99 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \
100 if (haslck) \
101 mtx_unlock(lck); \
102 haslck = 0; \
103 } while (0)
104
105 TASKQUEUE_DEFINE_THREAD(kqueue_ctx);
106
107 static int kevent_copyout(void *arg, struct kevent *kevp, int count);
108 static int kevent_copyin(void *arg, struct kevent *kevp, int count);
109 static int kqueue_register(struct kqueue *kq, struct kevent *kev,
110 struct thread *td, int mflag);
111 static int kqueue_acquire(struct file *fp, struct kqueue **kqp);
112 static void kqueue_release(struct kqueue *kq, int locked);
113 static void kqueue_destroy(struct kqueue *kq);
114 static void kqueue_drain(struct kqueue *kq, struct thread *td);
115 static int kqueue_expand(struct kqueue *kq, const struct filterops *fops,
116 uintptr_t ident, int mflag);
117 static void kqueue_task(void *arg, int pending);
118 static int kqueue_scan(struct kqueue *kq, int maxevents,
119 struct kevent_copyops *k_ops,
120 const struct timespec *timeout,
121 struct kevent *keva, struct thread *td);
122 static void kqueue_wakeup(struct kqueue *kq);
123 static const struct filterops *kqueue_fo_find(int filt);
124 static void kqueue_fo_release(int filt);
125 struct g_kevent_args;
126 static int kern_kevent_generic(struct thread *td,
127 struct g_kevent_args *uap,
128 struct kevent_copyops *k_ops, const char *struct_name);
129
130 static fo_ioctl_t kqueue_ioctl;
131 static fo_poll_t kqueue_poll;
132 static fo_kqfilter_t kqueue_kqfilter;
133 static fo_stat_t kqueue_stat;
134 static fo_close_t kqueue_close;
135 static fo_fill_kinfo_t kqueue_fill_kinfo;
136 static fo_fork_t kqueue_fork;
137
138 static const struct fileops kqueueops = {
139 .fo_read = invfo_rdwr,
140 .fo_write = invfo_rdwr,
141 .fo_truncate = invfo_truncate,
142 .fo_ioctl = kqueue_ioctl,
143 .fo_poll = kqueue_poll,
144 .fo_kqfilter = kqueue_kqfilter,
145 .fo_stat = kqueue_stat,
146 .fo_close = kqueue_close,
147 .fo_chmod = invfo_chmod,
148 .fo_chown = invfo_chown,
149 .fo_sendfile = invfo_sendfile,
150 .fo_cmp = file_kcmp_generic,
151 .fo_fork = kqueue_fork,
152 .fo_fill_kinfo = kqueue_fill_kinfo,
153 .fo_flags = DFLAG_FORK,
154 };
155
156 static int knote_attach(struct knote *kn, struct kqueue *kq);
157 static void knote_drop(struct knote *kn, struct thread *td);
158 static void knote_drop_detached(struct knote *kn, struct thread *td);
159 static void knote_enqueue(struct knote *kn);
160 static void knote_dequeue(struct knote *kn);
161 static void knote_init(void *);
162 static struct knote *knote_alloc(int mflag);
163 static void knote_free(struct knote *kn);
164
165 static void filt_kqdetach(struct knote *kn);
166 static int filt_kqueue(struct knote *kn, long hint);
167 static int filt_procattach(struct knote *kn);
168 static void filt_procdetach(struct knote *kn);
169 static int filt_proc(struct knote *kn, long hint);
170 static int filt_jailattach(struct knote *kn);
171 static void filt_jaildetach(struct knote *kn);
172 static int filt_jail(struct knote *kn, long hint);
173 static int filt_fileattach(struct knote *kn);
174 static void filt_timerexpire(void *knx);
175 static void filt_timerexpire_l(struct knote *kn, bool proc_locked);
176 static int filt_timerattach(struct knote *kn);
177 static void filt_timerdetach(struct knote *kn);
178 static void filt_timerstart(struct knote *kn, sbintime_t to);
179 static void filt_timertouch(struct knote *kn, struct kevent *kev,
180 u_long type);
181 static int filt_timercopy(struct knote *kn, struct proc *p1);
182 static int filt_timervalidate(struct knote *kn, sbintime_t *to);
183 static int filt_timer(struct knote *kn, long hint);
184 static int filt_userattach(struct knote *kn);
185 static void filt_userdetach(struct knote *kn);
186 static int filt_user(struct knote *kn, long hint);
187 static void filt_usertouch(struct knote *kn, struct kevent *kev,
188 u_long type);
189
190 static const struct filterops file_filtops = {
191 .f_isfd = 1,
192 .f_attach = filt_fileattach,
193 .f_copy = knote_triv_copy,
194 };
195 static const struct filterops kqread_filtops = {
196 .f_isfd = 1,
197 .f_detach = filt_kqdetach,
198 .f_event = filt_kqueue,
199 .f_copy = knote_triv_copy,
200 };
201 /* XXX - move to kern_proc.c? */
202 static const struct filterops proc_filtops = {
203 .f_isfd = 0,
204 .f_attach = filt_procattach,
205 .f_detach = filt_procdetach,
206 .f_event = filt_proc,
207 .f_copy = knote_triv_copy,
208 };
209 static const struct filterops jail_filtops = {
210 .f_isfd = 0,
211 .f_attach = filt_jailattach,
212 .f_detach = filt_jaildetach,
213 .f_event = filt_jail,
214 .f_copy = knote_triv_copy,
215 };
216 static const struct filterops timer_filtops = {
217 .f_isfd = 0,
218 .f_attach = filt_timerattach,
219 .f_detach = filt_timerdetach,
220 .f_event = filt_timer,
221 .f_touch = filt_timertouch,
222 .f_copy = filt_timercopy,
223 };
224 static const struct filterops user_filtops = {
225 .f_attach = filt_userattach,
226 .f_detach = filt_userdetach,
227 .f_event = filt_user,
228 .f_touch = filt_usertouch,
229 .f_copy = knote_triv_copy,
230 };
231
232 static uma_zone_t knote_zone;
233 static unsigned int __exclusive_cache_line kq_ncallouts;
234 static unsigned int kq_calloutmax = 4 * 1024;
235 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
236 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
237
238 /* XXX - ensure not influx ? */
239 #define KNOTE_ACTIVATE(kn, islock) do { \
240 if ((islock)) \
241 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \
242 else \
243 KQ_LOCK((kn)->kn_kq); \
244 (kn)->kn_status |= KN_ACTIVE; \
245 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
246 knote_enqueue((kn)); \
247 if (!(islock)) \
248 KQ_UNLOCK((kn)->kn_kq); \
249 } while (0)
250 #define KQ_LOCK(kq) do { \
251 mtx_lock(&(kq)->kq_lock); \
252 } while (0)
253 #define KQ_FLUX_WAKEUP(kq) do { \
254 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \
255 (kq)->kq_state &= ~KQ_FLUXWAIT; \
256 wakeup((kq)); \
257 } \
258 } while (0)
259 #define KQ_UNLOCK_FLUX(kq) do { \
260 KQ_FLUX_WAKEUP(kq); \
261 mtx_unlock(&(kq)->kq_lock); \
262 } while (0)
263 #define KQ_UNLOCK(kq) do { \
264 mtx_unlock(&(kq)->kq_lock); \
265 } while (0)
266 #define KQ_OWNED(kq) do { \
267 mtx_assert(&(kq)->kq_lock, MA_OWNED); \
268 } while (0)
269 #define KQ_NOTOWNED(kq) do { \
270 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \
271 } while (0)
272
273 static struct knlist *
kn_list_lock(struct knote * kn)274 kn_list_lock(struct knote *kn)
275 {
276 struct knlist *knl;
277
278 knl = kn->kn_knlist;
279 if (knl != NULL)
280 knl->kl_lock(knl->kl_lockarg);
281 return (knl);
282 }
283
284 static void
kn_list_unlock(struct knlist * knl)285 kn_list_unlock(struct knlist *knl)
286 {
287 bool do_free;
288
289 if (knl == NULL)
290 return;
291 do_free = knl->kl_autodestroy && knlist_empty(knl);
292 knl->kl_unlock(knl->kl_lockarg);
293 if (do_free) {
294 knlist_destroy(knl);
295 free(knl, M_KQUEUE);
296 }
297 }
298
299 static bool
kn_in_flux(struct knote * kn)300 kn_in_flux(struct knote *kn)
301 {
302
303 return (kn->kn_influx > 0);
304 }
305
306 static void
kn_enter_flux(struct knote * kn)307 kn_enter_flux(struct knote *kn)
308 {
309
310 KQ_OWNED(kn->kn_kq);
311 MPASS(kn->kn_influx < INT_MAX);
312 kn->kn_influx++;
313 }
314
315 static bool
kn_leave_flux(struct knote * kn)316 kn_leave_flux(struct knote *kn)
317 {
318
319 KQ_OWNED(kn->kn_kq);
320 MPASS(kn->kn_influx > 0);
321 kn->kn_influx--;
322 return (kn->kn_influx == 0);
323 }
324
325 #define KNL_ASSERT_LOCK(knl, islocked) do { \
326 if (islocked) \
327 KNL_ASSERT_LOCKED(knl); \
328 else \
329 KNL_ASSERT_UNLOCKED(knl); \
330 } while (0)
331 #ifdef INVARIANTS
332 #define KNL_ASSERT_LOCKED(knl) do { \
333 knl->kl_assert_lock((knl)->kl_lockarg, LA_LOCKED); \
334 } while (0)
335 #define KNL_ASSERT_UNLOCKED(knl) do { \
336 knl->kl_assert_lock((knl)->kl_lockarg, LA_UNLOCKED); \
337 } while (0)
338 #else /* !INVARIANTS */
339 #define KNL_ASSERT_LOCKED(knl) do {} while (0)
340 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
341 #endif /* INVARIANTS */
342
343 #ifndef KN_HASHSIZE
344 #define KN_HASHSIZE 64 /* XXX should be tunable */
345 #endif
346
347 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
348
349 static int
filt_nullattach(struct knote * kn)350 filt_nullattach(struct knote *kn)
351 {
352
353 return (ENXIO);
354 };
355
356 static const struct filterops null_filtops = {
357 .f_isfd = 0,
358 .f_attach = filt_nullattach,
359 .f_copy = knote_triv_copy,
360 };
361
362 /* XXX - make SYSINIT to add these, and move into respective modules. */
363 extern const struct filterops sig_filtops;
364 extern const struct filterops fs_filtops;
365
366 /*
367 * Table for all system-defined filters.
368 */
369 static struct mtx filterops_lock;
370 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", MTX_DEF);
371 static struct {
372 const struct filterops *for_fop;
373 int for_nolock;
374 int for_refcnt;
375 } sysfilt_ops[EVFILT_SYSCOUNT] = {
376 [~EVFILT_READ] = { &file_filtops, 1 },
377 [~EVFILT_WRITE] = { &file_filtops, 1 },
378 [~EVFILT_AIO] = { &null_filtops },
379 [~EVFILT_VNODE] = { &file_filtops, 1 },
380 [~EVFILT_PROC] = { &proc_filtops, 1 },
381 [~EVFILT_SIGNAL] = { &sig_filtops, 1 },
382 [~EVFILT_TIMER] = { &timer_filtops, 1 },
383 [~EVFILT_PROCDESC] = { &file_filtops, 1 },
384 [~EVFILT_FS] = { &fs_filtops, 1 },
385 [~EVFILT_LIO] = { &null_filtops },
386 [~EVFILT_USER] = { &user_filtops, 1 },
387 [~EVFILT_SENDFILE] = { &null_filtops },
388 [~EVFILT_EMPTY] = { &file_filtops, 1 },
389 [~EVFILT_JAIL] = { &jail_filtops, 1 },
390 [~EVFILT_JAILDESC] = { &file_filtops, 1 },
391 };
392
393 /*
394 * Simple redirection for all cdevsw style objects to call their fo_kqfilter
395 * method.
396 */
397 static int
filt_fileattach(struct knote * kn)398 filt_fileattach(struct knote *kn)
399 {
400
401 return (fo_kqfilter(kn->kn_fp, kn));
402 }
403
404 /*ARGSUSED*/
405 static int
kqueue_kqfilter(struct file * fp,struct knote * kn)406 kqueue_kqfilter(struct file *fp, struct knote *kn)
407 {
408 struct kqueue *kq = kn->kn_fp->f_data;
409
410 if (kn->kn_filter != EVFILT_READ)
411 return (EINVAL);
412
413 kn->kn_status |= KN_KQUEUE;
414 kn->kn_fop = &kqread_filtops;
415 knlist_add(&kq->kq_sel.si_note, kn, 0);
416
417 return (0);
418 }
419
420 static void
filt_kqdetach(struct knote * kn)421 filt_kqdetach(struct knote *kn)
422 {
423 struct kqueue *kq = kn->kn_fp->f_data;
424
425 knlist_remove(&kq->kq_sel.si_note, kn, 0);
426 }
427
428 /*ARGSUSED*/
429 static int
filt_kqueue(struct knote * kn,long hint)430 filt_kqueue(struct knote *kn, long hint)
431 {
432 struct kqueue *kq = kn->kn_fp->f_data;
433
434 kn->kn_data = kq->kq_count;
435 return (kn->kn_data > 0);
436 }
437
438 /* XXX - move to kern_proc.c? */
439 static int
filt_procattach(struct knote * kn)440 filt_procattach(struct knote *kn)
441 {
442 struct proc *p;
443 int error;
444 bool exiting, immediate;
445
446 exiting = immediate = false;
447 if (kn->kn_sfflags & NOTE_EXIT)
448 p = pfind_any(kn->kn_id);
449 else
450 p = pfind(kn->kn_id);
451 if (p == NULL)
452 return (ESRCH);
453 if (p->p_flag & P_WEXIT)
454 exiting = true;
455
456 if ((error = p_cansee(curthread, p))) {
457 PROC_UNLOCK(p);
458 return (error);
459 }
460
461 kn->kn_ptr.p_proc = p;
462 kn->kn_flags |= EV_CLEAR; /* automatically set */
463
464 /*
465 * Internal flag indicating registration done by kernel for the
466 * purposes of getting a NOTE_CHILD notification.
467 */
468 if (kn->kn_flags & EV_FLAG2) {
469 kn->kn_flags &= ~EV_FLAG2;
470 kn->kn_data = kn->kn_sdata; /* ppid */
471 kn->kn_fflags = NOTE_CHILD;
472 kn->kn_sfflags &= ~(NOTE_EXIT | NOTE_EXEC | NOTE_FORK);
473 immediate = true; /* Force immediate activation of child note. */
474 }
475 /*
476 * Internal flag indicating registration done by kernel (for other than
477 * NOTE_CHILD).
478 */
479 if (kn->kn_flags & EV_FLAG1) {
480 kn->kn_flags &= ~EV_FLAG1;
481 }
482
483 knlist_add(p->p_klist, kn, 1);
484
485 /*
486 * Immediately activate any child notes or, in the case of a zombie
487 * target process, exit notes. The latter is necessary to handle the
488 * case where the target process, e.g. a child, dies before the kevent
489 * is registered.
490 */
491 if (immediate || (exiting && filt_proc(kn, NOTE_EXIT)))
492 KNOTE_ACTIVATE(kn, 0);
493
494 PROC_UNLOCK(p);
495
496 return (0);
497 }
498
499 /*
500 * The knote may be attached to a different process, which may exit,
501 * leaving nothing for the knote to be attached to. So when the process
502 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
503 * it will be deleted when read out. However, as part of the knote deletion,
504 * this routine is called, so a check is needed to avoid actually performing
505 * a detach, because the original process does not exist any more.
506 */
507 /* XXX - move to kern_proc.c? */
508 static void
filt_procdetach(struct knote * kn)509 filt_procdetach(struct knote *kn)
510 {
511
512 knlist_remove(kn->kn_knlist, kn, 0);
513 kn->kn_ptr.p_proc = NULL;
514 }
515
516 /* XXX - move to kern_proc.c? */
517 static int
filt_proc(struct knote * kn,long hint)518 filt_proc(struct knote *kn, long hint)
519 {
520 struct proc *p;
521 u_int event;
522
523 p = kn->kn_ptr.p_proc;
524 if (p == NULL) /* already activated, from attach filter */
525 return (0);
526
527 /* Mask off extra data. */
528 event = (u_int)hint & NOTE_PCTRLMASK;
529
530 /* If the user is interested in this event, record it. */
531 if (kn->kn_sfflags & event)
532 kn->kn_fflags |= event;
533
534 /* Process is gone, so flag the event as finished. */
535 if (event == NOTE_EXIT) {
536 kn->kn_flags |= EV_EOF | EV_ONESHOT;
537 kn->kn_ptr.p_proc = NULL;
538 if (kn->kn_fflags & NOTE_EXIT)
539 kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig);
540 if (kn->kn_fflags == 0)
541 kn->kn_flags |= EV_DROP;
542 return (1);
543 }
544
545 return (kn->kn_fflags != 0);
546 }
547
548 /*
549 * Called when the process forked. It mostly does the same as the
550 * knote(), activating all knotes registered to be activated when the
551 * process forked. Additionally, for each knote attached to the
552 * parent, check whether user wants to track the new process. If so
553 * attach a new knote to it, and immediately report an event with the
554 * child's pid.
555 */
556 void
knote_fork(struct knlist * list,int pid)557 knote_fork(struct knlist *list, int pid)
558 {
559 struct kqueue *kq;
560 struct knote *kn;
561 struct kevent kev;
562 int error;
563
564 MPASS(list != NULL);
565 KNL_ASSERT_LOCKED(list);
566 if (SLIST_EMPTY(&list->kl_list))
567 return;
568
569 memset(&kev, 0, sizeof(kev));
570 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
571 kq = kn->kn_kq;
572 KQ_LOCK(kq);
573 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) {
574 KQ_UNLOCK(kq);
575 continue;
576 }
577
578 /*
579 * The same as knote(), activate the event.
580 */
581 if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
582 if (kn->kn_fop->f_event(kn, NOTE_FORK))
583 KNOTE_ACTIVATE(kn, 1);
584 KQ_UNLOCK(kq);
585 continue;
586 }
587
588 /*
589 * The NOTE_TRACK case. In addition to the activation
590 * of the event, we need to register new events to
591 * track the child. Drop the locks in preparation for
592 * the call to kqueue_register().
593 */
594 kn_enter_flux(kn);
595 KQ_UNLOCK(kq);
596 list->kl_unlock(list->kl_lockarg);
597
598 /*
599 * Activate existing knote and register tracking knotes with
600 * new process.
601 *
602 * First register a knote to get just the child notice. This
603 * must be a separate note from a potential NOTE_EXIT
604 * notification since both NOTE_CHILD and NOTE_EXIT are defined
605 * to use the data field (in conflicting ways).
606 */
607 kev.ident = pid;
608 kev.filter = kn->kn_filter;
609 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT |
610 EV_FLAG2;
611 kev.fflags = kn->kn_sfflags;
612 kev.data = kn->kn_id; /* parent */
613 kev.udata = kn->kn_kevent.udata;/* preserve udata */
614 error = kqueue_register(kq, &kev, NULL, M_NOWAIT);
615 if (error)
616 kn->kn_fflags |= NOTE_TRACKERR;
617
618 /*
619 * Then register another knote to track other potential events
620 * from the new process.
621 */
622 kev.ident = pid;
623 kev.filter = kn->kn_filter;
624 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
625 kev.fflags = kn->kn_sfflags;
626 kev.data = kn->kn_id; /* parent */
627 kev.udata = kn->kn_kevent.udata;/* preserve udata */
628 error = kqueue_register(kq, &kev, NULL, M_NOWAIT);
629
630 /*
631 * Serialize updates to the kn_kevent fields with threads
632 * scanning the queue.
633 */
634 list->kl_lock(list->kl_lockarg);
635 if (error)
636 kn->kn_fflags |= NOTE_TRACKERR;
637 if (kn->kn_fop->f_event(kn, NOTE_FORK)) {
638 KQ_LOCK(kq);
639 KNOTE_ACTIVATE(kn, 1);
640 } else {
641 KQ_LOCK(kq);
642 }
643 kn_leave_flux(kn);
644 KQ_UNLOCK_FLUX(kq);
645 }
646 }
647
648 int
filt_jailattach(struct knote * kn)649 filt_jailattach(struct knote *kn)
650 {
651 struct prison *pr;
652
653 if (kn->kn_id == 0) {
654 /* Let jid=0 watch the current prison (including prison0). */
655 pr = curthread->td_ucred->cr_prison;
656 mtx_lock(&pr->pr_mtx);
657 } else {
658 sx_slock(&allprison_lock);
659 pr = prison_find_child(curthread->td_ucred->cr_prison,
660 kn->kn_id);
661 sx_sunlock(&allprison_lock);
662 if (pr == NULL)
663 return (ENOENT);
664 if (!prison_isalive(pr)) {
665 mtx_unlock(&pr->pr_mtx);
666 return (ENOENT);
667 }
668 }
669 kn->kn_ptr.p_prison = pr;
670 kn->kn_flags |= EV_CLEAR;
671 knlist_add(pr->pr_klist, kn, 1);
672 mtx_unlock(&pr->pr_mtx);
673 return (0);
674 }
675
676 void
filt_jaildetach(struct knote * kn)677 filt_jaildetach(struct knote *kn)
678 {
679 if (kn->kn_ptr.p_prison != NULL) {
680 knlist_remove(kn->kn_knlist, kn, 0);
681 kn->kn_ptr.p_prison = NULL;
682 } else
683 kn->kn_status |= KN_DETACHED;
684 }
685
686 int
filt_jail(struct knote * kn,long hint)687 filt_jail(struct knote *kn, long hint)
688 {
689 struct prison *pr;
690 u_int event;
691
692 pr = kn->kn_ptr.p_prison;
693 if (pr == NULL) /* already activated, from attach filter */
694 return (0);
695
696 /*
697 * Mask off extra data. In the NOTE_JAIL_CHILD case, that's
698 * everything except the NOTE_JAIL_CHILD bit itself, since a
699 * JID is any positive integer.
700 */
701 event = ((u_int)hint & NOTE_JAIL_CHILD) ? NOTE_JAIL_CHILD :
702 (u_int)hint & NOTE_JAIL_CTRLMASK;
703
704 /* If the user is interested in this event, record it. */
705 if (kn->kn_sfflags & event) {
706 kn->kn_fflags |= event;
707 /* Report the created jail id or attached process id. */
708 if (event == NOTE_JAIL_CHILD || event == NOTE_JAIL_ATTACH) {
709 if (kn->kn_data != 0)
710 kn->kn_fflags |= NOTE_JAIL_MULTI;
711 kn->kn_data = (kn->kn_fflags & NOTE_JAIL_MULTI) ? 0U :
712 (u_int)hint & ~event;
713 }
714 }
715
716 /* Prison is gone, so flag the event as finished. */
717 if (event == NOTE_JAIL_REMOVE) {
718 kn->kn_flags |= EV_EOF | EV_ONESHOT;
719 kn->kn_ptr.p_prison = NULL;
720 if (kn->kn_fflags == 0)
721 kn->kn_flags |= EV_DROP;
722 return (1);
723 }
724
725 return (kn->kn_fflags != 0);
726 }
727
728 /*
729 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the
730 * interval timer support code.
731 */
732
733 #define NOTE_TIMER_PRECMASK \
734 (NOTE_SECONDS | NOTE_MSECONDS | NOTE_USECONDS | NOTE_NSECONDS)
735
736 static sbintime_t
timer2sbintime(int64_t data,unsigned int flags)737 timer2sbintime(int64_t data, unsigned int flags)
738 {
739 int64_t secs;
740
741 /*
742 * Macros for converting to the fractional second portion of an
743 * sbintime_t using 64bit multiplication to improve precision.
744 */
745 #define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32)
746 #define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32)
747 #define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32)
748 switch (flags & NOTE_TIMER_PRECMASK) {
749 case NOTE_SECONDS:
750 #ifdef __LP64__
751 if (data > (SBT_MAX / SBT_1S))
752 return (SBT_MAX);
753 #endif
754 return ((sbintime_t)data << 32);
755 case NOTE_MSECONDS: /* FALLTHROUGH */
756 case 0:
757 if (data >= 1000) {
758 secs = data / 1000;
759 #ifdef __LP64__
760 if (secs > (SBT_MAX / SBT_1S))
761 return (SBT_MAX);
762 #endif
763 return (secs << 32 | MS_TO_SBT(data % 1000));
764 }
765 return (MS_TO_SBT(data));
766 case NOTE_USECONDS:
767 if (data >= 1000000) {
768 secs = data / 1000000;
769 #ifdef __LP64__
770 if (secs > (SBT_MAX / SBT_1S))
771 return (SBT_MAX);
772 #endif
773 return (secs << 32 | US_TO_SBT(data % 1000000));
774 }
775 return (US_TO_SBT(data));
776 case NOTE_NSECONDS:
777 if (data >= 1000000000) {
778 secs = data / 1000000000;
779 #ifdef __LP64__
780 if (secs > (SBT_MAX / SBT_1S))
781 return (SBT_MAX);
782 #endif
783 return (secs << 32 | NS_TO_SBT(data % 1000000000));
784 }
785 return (NS_TO_SBT(data));
786 default:
787 break;
788 }
789 return (-1);
790 }
791
792 struct kq_timer_cb_data {
793 struct callout c;
794 struct proc *p;
795 struct knote *kn;
796 int cpuid;
797 int flags;
798 TAILQ_ENTRY(kq_timer_cb_data) link;
799 sbintime_t next; /* next timer event fires at */
800 sbintime_t to; /* precalculated timer period, 0 for abs */
801 };
802
803 #define KQ_TIMER_CB_ENQUEUED 0x01
804
805 static void
kqtimer_sched_callout(struct kq_timer_cb_data * kc)806 kqtimer_sched_callout(struct kq_timer_cb_data *kc)
807 {
808 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kc->kn,
809 kc->cpuid, C_ABSOLUTE);
810 }
811
812 void
kqtimer_proc_continue(struct proc * p)813 kqtimer_proc_continue(struct proc *p)
814 {
815 struct kq_timer_cb_data *kc, *kc1;
816 sbintime_t now;
817
818 PROC_LOCK_ASSERT(p, MA_OWNED);
819
820 now = sbinuptime();
821 TAILQ_FOREACH_SAFE(kc, &p->p_kqtim_stop, link, kc1) {
822 TAILQ_REMOVE(&p->p_kqtim_stop, kc, link);
823 kc->flags &= ~KQ_TIMER_CB_ENQUEUED;
824 if (kc->next <= now)
825 filt_timerexpire_l(kc->kn, true);
826 else
827 kqtimer_sched_callout(kc);
828 }
829 }
830
831 static void
filt_timerexpire_l(struct knote * kn,bool proc_locked)832 filt_timerexpire_l(struct knote *kn, bool proc_locked)
833 {
834 struct kq_timer_cb_data *kc;
835 struct proc *p;
836 uint64_t delta;
837 sbintime_t now;
838
839 kc = kn->kn_ptr.p_v;
840
841 if ((kn->kn_flags & EV_ONESHOT) != 0 || kc->to == 0) {
842 kn->kn_data++;
843 KNOTE_ACTIVATE(kn, 0);
844 return;
845 }
846
847 now = sbinuptime();
848 if (now >= kc->next) {
849 delta = (now - kc->next) / kc->to;
850 if (delta == 0)
851 delta = 1;
852 kn->kn_data += delta;
853 kc->next += delta * kc->to;
854 if (now >= kc->next) /* overflow */
855 kc->next = now + kc->to;
856 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
857 }
858
859 /*
860 * Initial check for stopped kc->p is racy. It is fine to
861 * miss the set of the stop flags, at worst we would schedule
862 * one more callout. On the other hand, it is not fine to not
863 * schedule when we we missed clearing of the flags, we
864 * recheck them under the lock and observe consistent state.
865 */
866 p = kc->p;
867 if (P_SHOULDSTOP(p) || P_KILLED(p)) {
868 if (!proc_locked)
869 PROC_LOCK(p);
870 if (P_SHOULDSTOP(p) || P_KILLED(p)) {
871 if ((kc->flags & KQ_TIMER_CB_ENQUEUED) == 0) {
872 /*
873 * Insert into head so that
874 * kqtimer_proc_continue() does not
875 * iterate into us again.
876 */
877 kc->flags |= KQ_TIMER_CB_ENQUEUED;
878 TAILQ_INSERT_HEAD(&p->p_kqtim_stop, kc, link);
879 }
880 if (!proc_locked)
881 PROC_UNLOCK(p);
882 return;
883 }
884 if (!proc_locked)
885 PROC_UNLOCK(p);
886 }
887 kqtimer_sched_callout(kc);
888 }
889
890 static void
filt_timerexpire(void * knx)891 filt_timerexpire(void *knx)
892 {
893 filt_timerexpire_l(knx, false);
894 }
895
896 /*
897 * data contains amount of time to sleep
898 */
899 static int
filt_timervalidate(struct knote * kn,sbintime_t * to)900 filt_timervalidate(struct knote *kn, sbintime_t *to)
901 {
902 struct bintime bt;
903 sbintime_t sbt;
904
905 if (kn->kn_sdata < 0)
906 return (EINVAL);
907 if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0)
908 kn->kn_sdata = 1;
909 /*
910 * The only fflags values supported are the timer unit
911 * (precision) and the absolute time indicator.
912 */
913 if ((kn->kn_sfflags & ~(NOTE_TIMER_PRECMASK | NOTE_ABSTIME)) != 0)
914 return (EINVAL);
915
916 *to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags);
917 if (*to < 0)
918 return (EINVAL);
919 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) {
920 getboottimebin(&bt);
921 sbt = bttosbt(bt);
922 *to = MAX(0, *to - sbt);
923 }
924 return (0);
925 }
926
927 static int
filt_timerattach(struct knote * kn)928 filt_timerattach(struct knote *kn)
929 {
930 struct kq_timer_cb_data *kc;
931 sbintime_t to;
932 int error;
933
934 to = -1;
935 error = filt_timervalidate(kn, &to);
936 if (error != 0)
937 return (error);
938 KASSERT(to > 0 || (kn->kn_flags & EV_ONESHOT) != 0 ||
939 (kn->kn_sfflags & NOTE_ABSTIME) != 0,
940 ("%s: periodic timer has a calculated zero timeout", __func__));
941 KASSERT(to >= 0,
942 ("%s: timer has a calculated negative timeout", __func__));
943
944 if (atomic_fetchadd_int(&kq_ncallouts, 1) + 1 > kq_calloutmax) {
945 atomic_subtract_int(&kq_ncallouts, 1);
946 return (ENOMEM);
947 }
948
949 if ((kn->kn_sfflags & NOTE_ABSTIME) == 0)
950 kn->kn_flags |= EV_CLEAR; /* automatically set */
951 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */
952 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK);
953 kc->kn = kn;
954 kc->p = curproc;
955 kc->cpuid = PCPU_GET(cpuid);
956 kc->flags = 0;
957 callout_init(&kc->c, 1);
958 filt_timerstart(kn, to);
959
960 return (0);
961 }
962
963 static int
filt_timercopy(struct knote * kn,struct proc * p)964 filt_timercopy(struct knote *kn, struct proc *p)
965 {
966 struct kq_timer_cb_data *kc_src, *kc;
967
968 if (atomic_fetchadd_int(&kq_ncallouts, 1) + 1 > kq_calloutmax) {
969 atomic_subtract_int(&kq_ncallouts, 1);
970 return (ENOMEM);
971 }
972
973 kn->kn_status &= ~KN_DETACHED;
974 kc_src = kn->kn_ptr.p_v;
975 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK);
976 kc->kn = kn;
977 kc->p = p;
978 kc->flags = kc_src->flags & ~KQ_TIMER_CB_ENQUEUED;
979 kc->next = kc_src->next;
980 kc->to = kc_src->to;
981 kc->cpuid = PCPU_GET(cpuid);
982 callout_init(&kc->c, 1);
983 kqtimer_sched_callout(kc);
984 return (0);
985 }
986
987 static void
filt_timerstart(struct knote * kn,sbintime_t to)988 filt_timerstart(struct knote *kn, sbintime_t to)
989 {
990 struct kq_timer_cb_data *kc;
991
992 kc = kn->kn_ptr.p_v;
993 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) {
994 kc->next = to;
995 kc->to = 0;
996 } else {
997 kc->next = to + sbinuptime();
998 kc->to = to;
999 }
1000 kqtimer_sched_callout(kc);
1001 }
1002
1003 static void
filt_timerdetach(struct knote * kn)1004 filt_timerdetach(struct knote *kn)
1005 {
1006 struct kq_timer_cb_data *kc;
1007 unsigned int old __unused;
1008 bool pending;
1009
1010 kc = kn->kn_ptr.p_v;
1011 do {
1012 callout_drain(&kc->c);
1013
1014 /*
1015 * kqtimer_proc_continue() might have rescheduled this callout.
1016 * Double-check, using the process mutex as an interlock.
1017 */
1018 PROC_LOCK(kc->p);
1019 if ((kc->flags & KQ_TIMER_CB_ENQUEUED) != 0) {
1020 kc->flags &= ~KQ_TIMER_CB_ENQUEUED;
1021 TAILQ_REMOVE(&kc->p->p_kqtim_stop, kc, link);
1022 }
1023 pending = callout_pending(&kc->c);
1024 PROC_UNLOCK(kc->p);
1025 } while (pending);
1026 free(kc, M_KQUEUE);
1027 old = atomic_fetchadd_int(&kq_ncallouts, -1);
1028 KASSERT(old > 0, ("Number of callouts cannot become negative"));
1029 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */
1030 }
1031
1032 static void
filt_timertouch(struct knote * kn,struct kevent * kev,u_long type)1033 filt_timertouch(struct knote *kn, struct kevent *kev, u_long type)
1034 {
1035 struct kq_timer_cb_data *kc;
1036 struct kqueue *kq;
1037 sbintime_t to;
1038 int error;
1039
1040 switch (type) {
1041 case EVENT_REGISTER:
1042 /* Handle re-added timers that update data/fflags */
1043 if (kev->flags & EV_ADD) {
1044 kc = kn->kn_ptr.p_v;
1045
1046 /* Drain any existing callout. */
1047 callout_drain(&kc->c);
1048
1049 /* Throw away any existing undelivered record
1050 * of the timer expiration. This is done under
1051 * the presumption that if a process is
1052 * re-adding this timer with new parameters,
1053 * it is no longer interested in what may have
1054 * happened under the old parameters. If it is
1055 * interested, it can wait for the expiration,
1056 * delete the old timer definition, and then
1057 * add the new one.
1058 *
1059 * This has to be done while the kq is locked:
1060 * - if enqueued, dequeue
1061 * - make it no longer active
1062 * - clear the count of expiration events
1063 */
1064 kq = kn->kn_kq;
1065 KQ_LOCK(kq);
1066 if (kn->kn_status & KN_QUEUED)
1067 knote_dequeue(kn);
1068
1069 kn->kn_status &= ~KN_ACTIVE;
1070 kn->kn_data = 0;
1071 KQ_UNLOCK(kq);
1072
1073 /* Reschedule timer based on new data/fflags */
1074 kn->kn_sfflags = kev->fflags;
1075 kn->kn_sdata = kev->data;
1076 error = filt_timervalidate(kn, &to);
1077 if (error != 0) {
1078 kn->kn_flags |= EV_ERROR;
1079 kn->kn_data = error;
1080 } else
1081 filt_timerstart(kn, to);
1082 }
1083 break;
1084
1085 case EVENT_PROCESS:
1086 *kev = kn->kn_kevent;
1087 if (kn->kn_flags & EV_CLEAR) {
1088 kn->kn_data = 0;
1089 kn->kn_fflags = 0;
1090 }
1091 break;
1092
1093 default:
1094 panic("filt_timertouch() - invalid type (%ld)", type);
1095 break;
1096 }
1097 }
1098
1099 static int
filt_timer(struct knote * kn,long hint)1100 filt_timer(struct knote *kn, long hint)
1101 {
1102
1103 return (kn->kn_data != 0);
1104 }
1105
1106 static int
filt_userattach(struct knote * kn)1107 filt_userattach(struct knote *kn)
1108 {
1109
1110 /*
1111 * EVFILT_USER knotes are not attached to anything in the kernel.
1112 */
1113 kn->kn_hook = NULL;
1114 if (kn->kn_fflags & NOTE_TRIGGER)
1115 kn->kn_hookid = 1;
1116 else
1117 kn->kn_hookid = 0;
1118 return (0);
1119 }
1120
1121 static void
filt_userdetach(__unused struct knote * kn)1122 filt_userdetach(__unused struct knote *kn)
1123 {
1124
1125 /*
1126 * EVFILT_USER knotes are not attached to anything in the kernel.
1127 */
1128 }
1129
1130 static int
filt_user(struct knote * kn,__unused long hint)1131 filt_user(struct knote *kn, __unused long hint)
1132 {
1133
1134 return (kn->kn_hookid);
1135 }
1136
1137 static void
filt_usertouch(struct knote * kn,struct kevent * kev,u_long type)1138 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
1139 {
1140 u_int ffctrl;
1141
1142 switch (type) {
1143 case EVENT_REGISTER:
1144 if (kev->fflags & NOTE_TRIGGER)
1145 kn->kn_hookid = 1;
1146
1147 ffctrl = kev->fflags & NOTE_FFCTRLMASK;
1148 kev->fflags &= NOTE_FFLAGSMASK;
1149 switch (ffctrl) {
1150 case NOTE_FFNOP:
1151 break;
1152
1153 case NOTE_FFAND:
1154 kn->kn_sfflags &= kev->fflags;
1155 break;
1156
1157 case NOTE_FFOR:
1158 kn->kn_sfflags |= kev->fflags;
1159 break;
1160
1161 case NOTE_FFCOPY:
1162 kn->kn_sfflags = kev->fflags;
1163 break;
1164
1165 default:
1166 /* XXX Return error? */
1167 break;
1168 }
1169 kn->kn_sdata = kev->data;
1170 if (kev->flags & EV_CLEAR) {
1171 kn->kn_hookid = 0;
1172 kn->kn_data = 0;
1173 kn->kn_fflags = 0;
1174 }
1175 break;
1176
1177 case EVENT_PROCESS:
1178 *kev = kn->kn_kevent;
1179 kev->fflags = kn->kn_sfflags;
1180 kev->data = kn->kn_sdata;
1181 if (kn->kn_flags & EV_CLEAR) {
1182 kn->kn_hookid = 0;
1183 kn->kn_data = 0;
1184 kn->kn_fflags = 0;
1185 }
1186 break;
1187
1188 default:
1189 panic("filt_usertouch() - invalid type (%ld)", type);
1190 break;
1191 }
1192 }
1193
1194 int
sys_kqueue(struct thread * td,struct kqueue_args * uap)1195 sys_kqueue(struct thread *td, struct kqueue_args *uap)
1196 {
1197
1198 return (kern_kqueue(td, 0, false, NULL));
1199 }
1200
1201 int
sys_kqueuex(struct thread * td,struct kqueuex_args * uap)1202 sys_kqueuex(struct thread *td, struct kqueuex_args *uap)
1203 {
1204 int flags;
1205
1206 if ((uap->flags & ~(KQUEUE_CLOEXEC | KQUEUE_CPONFORK)) != 0)
1207 return (EINVAL);
1208 flags = 0;
1209 if ((uap->flags & KQUEUE_CLOEXEC) != 0)
1210 flags |= O_CLOEXEC;
1211 return (kern_kqueue(td, flags, (uap->flags & KQUEUE_CPONFORK) != 0,
1212 NULL));
1213 }
1214
1215 static void
kqueue_init(struct kqueue * kq,bool cponfork)1216 kqueue_init(struct kqueue *kq, bool cponfork)
1217 {
1218
1219 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK);
1220 TAILQ_INIT(&kq->kq_head);
1221 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
1222 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
1223 if (cponfork)
1224 kq->kq_state |= KQ_CPONFORK;
1225 }
1226
1227 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)1228 kern_kqueue_alloc(struct thread *td, struct filedesc *fdp, int *fdip,
1229 struct file **fpp, int flags, struct filecaps *fcaps, bool cponfork,
1230 struct kqueue **kqp)
1231 {
1232 struct ucred *cred;
1233 struct kqueue *kq;
1234 int error;
1235
1236 cred = td->td_ucred;
1237 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES)))
1238 return (ENOMEM);
1239
1240 error = fdip != NULL ? falloc_caps(td, fpp, fdip, flags, fcaps) :
1241 _falloc_noinstall(td, fpp, 1);
1242 if (error != 0) {
1243 chgkqcnt(cred->cr_ruidinfo, -1, 0);
1244 return (error);
1245 }
1246
1247 /* An extra reference on `fp' has been held for us by falloc(). */
1248 kq = malloc(sizeof(*kq), M_KQUEUE, M_WAITOK | M_ZERO);
1249 kqueue_init(kq, cponfork);
1250 kq->kq_fdp = fdp;
1251 kq->kq_cred = crhold(cred);
1252
1253 if (fdip != NULL)
1254 FILEDESC_XLOCK(fdp);
1255 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
1256 if (fdip != NULL)
1257 FILEDESC_XUNLOCK(fdp);
1258
1259 finit(*fpp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
1260 *kqp = kq;
1261 return (0);
1262 }
1263
1264 int
kern_kqueue(struct thread * td,int flags,bool cponfork,struct filecaps * fcaps)1265 kern_kqueue(struct thread *td, int flags, bool cponfork, struct filecaps *fcaps)
1266 {
1267 struct kqueue *kq;
1268 struct file *fp;
1269 int fd, error;
1270
1271 error = kern_kqueue_alloc(td, td->td_proc->p_fd, &fd, &fp, flags,
1272 fcaps, cponfork, &kq);
1273 if (error != 0)
1274 return (error);
1275
1276 fdrop(fp, td);
1277
1278 td->td_retval[0] = fd;
1279 return (0);
1280 }
1281
1282 struct g_kevent_args {
1283 int fd;
1284 const void *changelist;
1285 int nchanges;
1286 void *eventlist;
1287 int nevents;
1288 const struct timespec *timeout;
1289 };
1290
1291 int
sys_kevent(struct thread * td,struct kevent_args * uap)1292 sys_kevent(struct thread *td, struct kevent_args *uap)
1293 {
1294 struct kevent_copyops k_ops = {
1295 .arg = uap,
1296 .k_copyout = kevent_copyout,
1297 .k_copyin = kevent_copyin,
1298 .kevent_size = sizeof(struct kevent),
1299 };
1300 struct g_kevent_args gk_args = {
1301 .fd = uap->fd,
1302 .changelist = uap->changelist,
1303 .nchanges = uap->nchanges,
1304 .eventlist = uap->eventlist,
1305 .nevents = uap->nevents,
1306 .timeout = uap->timeout,
1307 };
1308
1309 return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent"));
1310 }
1311
1312 static int
kern_kevent_generic(struct thread * td,struct g_kevent_args * uap,struct kevent_copyops * k_ops,const char * struct_name)1313 kern_kevent_generic(struct thread *td, struct g_kevent_args *uap,
1314 struct kevent_copyops *k_ops, const char *struct_name)
1315 {
1316 struct timespec ts, *tsp;
1317 #ifdef KTRACE
1318 struct kevent *eventlist = uap->eventlist;
1319 #endif
1320 int error;
1321
1322 if (uap->timeout != NULL) {
1323 error = copyin(uap->timeout, &ts, sizeof(ts));
1324 if (error)
1325 return (error);
1326 tsp = &ts;
1327 } else
1328 tsp = NULL;
1329
1330 #ifdef KTRACE
1331 if (KTRPOINT(td, KTR_STRUCT_ARRAY))
1332 ktrstructarray(struct_name, UIO_USERSPACE, uap->changelist,
1333 uap->nchanges, k_ops->kevent_size);
1334 #endif
1335
1336 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
1337 k_ops, tsp);
1338
1339 #ifdef KTRACE
1340 if (error == 0 && KTRPOINT(td, KTR_STRUCT_ARRAY))
1341 ktrstructarray(struct_name, UIO_USERSPACE, eventlist,
1342 td->td_retval[0], k_ops->kevent_size);
1343 #endif
1344
1345 return (error);
1346 }
1347
1348 /*
1349 * Copy 'count' items into the destination list pointed to by uap->eventlist.
1350 */
1351 static int
kevent_copyout(void * arg,struct kevent * kevp,int count)1352 kevent_copyout(void *arg, struct kevent *kevp, int count)
1353 {
1354 struct kevent_args *uap;
1355 int error;
1356
1357 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1358 uap = (struct kevent_args *)arg;
1359
1360 error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
1361 if (error == 0)
1362 uap->eventlist += count;
1363 return (error);
1364 }
1365
1366 /*
1367 * Copy 'count' items from the list pointed to by uap->changelist.
1368 */
1369 static int
kevent_copyin(void * arg,struct kevent * kevp,int count)1370 kevent_copyin(void *arg, struct kevent *kevp, int count)
1371 {
1372 struct kevent_args *uap;
1373 int error;
1374
1375 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1376 uap = (struct kevent_args *)arg;
1377
1378 error = copyin(uap->changelist, kevp, count * sizeof *kevp);
1379 if (error == 0)
1380 uap->changelist += count;
1381 return (error);
1382 }
1383
1384 #ifdef COMPAT_FREEBSD11
1385 static int
kevent11_copyout(void * arg,struct kevent * kevp,int count)1386 kevent11_copyout(void *arg, struct kevent *kevp, int count)
1387 {
1388 struct freebsd11_kevent_args *uap;
1389 struct freebsd11_kevent kev11;
1390 int error, i;
1391
1392 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1393 uap = (struct freebsd11_kevent_args *)arg;
1394
1395 for (i = 0; i < count; i++) {
1396 kev11.ident = kevp->ident;
1397 kev11.filter = kevp->filter;
1398 kev11.flags = kevp->flags;
1399 kev11.fflags = kevp->fflags;
1400 kev11.data = kevp->data;
1401 kev11.udata = kevp->udata;
1402 error = copyout(&kev11, uap->eventlist, sizeof(kev11));
1403 if (error != 0)
1404 break;
1405 uap->eventlist++;
1406 kevp++;
1407 }
1408 return (error);
1409 }
1410
1411 /*
1412 * Copy 'count' items from the list pointed to by uap->changelist.
1413 */
1414 static int
kevent11_copyin(void * arg,struct kevent * kevp,int count)1415 kevent11_copyin(void *arg, struct kevent *kevp, int count)
1416 {
1417 struct freebsd11_kevent_args *uap;
1418 struct freebsd11_kevent kev11;
1419 int error, i;
1420
1421 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
1422 uap = (struct freebsd11_kevent_args *)arg;
1423
1424 for (i = 0; i < count; i++) {
1425 error = copyin(uap->changelist, &kev11, sizeof(kev11));
1426 if (error != 0)
1427 break;
1428 kevp->ident = kev11.ident;
1429 kevp->filter = kev11.filter;
1430 kevp->flags = kev11.flags;
1431 kevp->fflags = kev11.fflags;
1432 kevp->data = (uintptr_t)kev11.data;
1433 kevp->udata = kev11.udata;
1434 bzero(&kevp->ext, sizeof(kevp->ext));
1435 uap->changelist++;
1436 kevp++;
1437 }
1438 return (error);
1439 }
1440
1441 int
freebsd11_kevent(struct thread * td,struct freebsd11_kevent_args * uap)1442 freebsd11_kevent(struct thread *td, struct freebsd11_kevent_args *uap)
1443 {
1444 struct kevent_copyops k_ops = {
1445 .arg = uap,
1446 .k_copyout = kevent11_copyout,
1447 .k_copyin = kevent11_copyin,
1448 .kevent_size = sizeof(struct freebsd11_kevent),
1449 };
1450 struct g_kevent_args gk_args = {
1451 .fd = uap->fd,
1452 .changelist = uap->changelist,
1453 .nchanges = uap->nchanges,
1454 .eventlist = uap->eventlist,
1455 .nevents = uap->nevents,
1456 .timeout = uap->timeout,
1457 };
1458
1459 return (kern_kevent_generic(td, &gk_args, &k_ops, "freebsd11_kevent"));
1460 }
1461 #endif
1462
1463 int
kern_kevent(struct thread * td,int fd,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout)1464 kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
1465 struct kevent_copyops *k_ops, const struct timespec *timeout)
1466 {
1467 cap_rights_t rights;
1468 struct file *fp;
1469 int error;
1470
1471 cap_rights_init_zero(&rights);
1472 if (nchanges > 0)
1473 cap_rights_set_one(&rights, CAP_KQUEUE_CHANGE);
1474 if (nevents > 0)
1475 cap_rights_set_one(&rights, CAP_KQUEUE_EVENT);
1476 error = fget(td, fd, &rights, &fp);
1477 if (error != 0)
1478 return (error);
1479
1480 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout);
1481 fdrop(fp, td);
1482
1483 return (error);
1484 }
1485
1486 static int
kqueue_kevent(struct kqueue * kq,struct thread * td,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout)1487 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents,
1488 struct kevent_copyops *k_ops, const struct timespec *timeout)
1489 {
1490 struct kevent keva[KQ_NEVENTS];
1491 struct kevent *kevp, *changes;
1492 int i, n, nerrors, error;
1493
1494 if (nchanges < 0)
1495 return (EINVAL);
1496
1497 nerrors = 0;
1498 while (nchanges > 0) {
1499 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
1500 error = k_ops->k_copyin(k_ops->arg, keva, n);
1501 if (error)
1502 return (error);
1503 changes = keva;
1504 for (i = 0; i < n; i++) {
1505 kevp = &changes[i];
1506 if (!kevp->filter)
1507 continue;
1508 kevp->flags &= ~EV_SYSFLAGS;
1509 error = kqueue_register(kq, kevp, td, M_WAITOK);
1510 if (error || (kevp->flags & EV_RECEIPT)) {
1511 if (nevents == 0)
1512 return (error);
1513 kevp->flags = EV_ERROR;
1514 kevp->data = error;
1515 (void)k_ops->k_copyout(k_ops->arg, kevp, 1);
1516 nevents--;
1517 nerrors++;
1518 }
1519 }
1520 nchanges -= n;
1521 }
1522 if (nerrors) {
1523 td->td_retval[0] = nerrors;
1524 return (0);
1525 }
1526
1527 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td));
1528 }
1529
1530 int
kern_kevent_fp(struct thread * td,struct file * fp,int nchanges,int nevents,struct kevent_copyops * k_ops,const struct timespec * timeout)1531 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents,
1532 struct kevent_copyops *k_ops, const struct timespec *timeout)
1533 {
1534 struct kqueue *kq;
1535 int error;
1536
1537 error = kqueue_acquire(fp, &kq);
1538 if (error != 0)
1539 return (error);
1540 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout);
1541 kqueue_release(kq, 0);
1542 return (error);
1543 }
1544
1545 /*
1546 * Performs a kevent() call on a temporarily created kqueue. This can be
1547 * used to perform one-shot polling, similar to poll() and select().
1548 */
1549 int
kern_kevent_anonymous(struct thread * td,int nevents,struct kevent_copyops * k_ops)1550 kern_kevent_anonymous(struct thread *td, int nevents,
1551 struct kevent_copyops *k_ops)
1552 {
1553 struct kqueue kq = {};
1554 int error;
1555
1556 kqueue_init(&kq, false);
1557 kq.kq_refcnt = 1;
1558 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL);
1559 kqueue_drain(&kq, td);
1560 kqueue_destroy(&kq);
1561 return (error);
1562 }
1563
1564 int
kqueue_add_filteropts(int filt,const struct filterops * filtops)1565 kqueue_add_filteropts(int filt, const struct filterops *filtops)
1566 {
1567 int error;
1568
1569 error = 0;
1570 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
1571 printf(
1572 "trying to add a filterop that is out of range: %d is beyond %d\n",
1573 ~filt, EVFILT_SYSCOUNT);
1574 return EINVAL;
1575 }
1576 mtx_lock(&filterops_lock);
1577 if (sysfilt_ops[~filt].for_fop != &null_filtops &&
1578 sysfilt_ops[~filt].for_fop != NULL)
1579 error = EEXIST;
1580 else {
1581 sysfilt_ops[~filt].for_fop = filtops;
1582 sysfilt_ops[~filt].for_refcnt = 0;
1583 }
1584 mtx_unlock(&filterops_lock);
1585
1586 return (error);
1587 }
1588
1589 int
kqueue_del_filteropts(int filt)1590 kqueue_del_filteropts(int filt)
1591 {
1592 int error;
1593
1594 error = 0;
1595 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1596 return EINVAL;
1597
1598 mtx_lock(&filterops_lock);
1599 if (sysfilt_ops[~filt].for_fop == &null_filtops ||
1600 sysfilt_ops[~filt].for_fop == NULL)
1601 error = EINVAL;
1602 else if (sysfilt_ops[~filt].for_refcnt != 0)
1603 error = EBUSY;
1604 else {
1605 sysfilt_ops[~filt].for_fop = &null_filtops;
1606 sysfilt_ops[~filt].for_refcnt = 0;
1607 }
1608 mtx_unlock(&filterops_lock);
1609
1610 return error;
1611 }
1612
1613 static const struct filterops *
kqueue_fo_find(int filt)1614 kqueue_fo_find(int filt)
1615 {
1616
1617 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1618 return NULL;
1619
1620 if (sysfilt_ops[~filt].for_nolock)
1621 return sysfilt_ops[~filt].for_fop;
1622
1623 mtx_lock(&filterops_lock);
1624 sysfilt_ops[~filt].for_refcnt++;
1625 if (sysfilt_ops[~filt].for_fop == NULL)
1626 sysfilt_ops[~filt].for_fop = &null_filtops;
1627 mtx_unlock(&filterops_lock);
1628
1629 return sysfilt_ops[~filt].for_fop;
1630 }
1631
1632 static void
kqueue_fo_release(int filt)1633 kqueue_fo_release(int filt)
1634 {
1635
1636 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
1637 return;
1638
1639 if (sysfilt_ops[~filt].for_nolock)
1640 return;
1641
1642 mtx_lock(&filterops_lock);
1643 KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
1644 ("filter object %d refcount not valid on release", filt));
1645 sysfilt_ops[~filt].for_refcnt--;
1646 mtx_unlock(&filterops_lock);
1647 }
1648
1649 /*
1650 * A ref to kq (obtained via kqueue_acquire) must be held.
1651 */
1652 static int
kqueue_register(struct kqueue * kq,struct kevent * kev,struct thread * td,int mflag)1653 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td,
1654 int mflag)
1655 {
1656 const struct filterops *fops;
1657 struct file *fp;
1658 struct knote *kn, *tkn;
1659 struct knlist *knl;
1660 int error, filt, event;
1661 int haskqglobal, filedesc_unlock;
1662
1663 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE))
1664 return (EINVAL);
1665
1666 fp = NULL;
1667 kn = NULL;
1668 knl = NULL;
1669 error = 0;
1670 haskqglobal = 0;
1671 filedesc_unlock = 0;
1672
1673 filt = kev->filter;
1674 fops = kqueue_fo_find(filt);
1675 if (fops == NULL)
1676 return EINVAL;
1677
1678 if (kev->flags & EV_ADD) {
1679 /* Reject an invalid flag pair early */
1680 if (kev->flags & EV_KEEPUDATA) {
1681 tkn = NULL;
1682 error = EINVAL;
1683 goto done;
1684 }
1685
1686 /*
1687 * Prevent waiting with locks. Non-sleepable
1688 * allocation failures are handled in the loop, only
1689 * if the spare knote appears to be actually required.
1690 */
1691 tkn = knote_alloc(mflag);
1692 } else {
1693 tkn = NULL;
1694 }
1695
1696 findkn:
1697 if (fops->f_isfd) {
1698 KASSERT(td != NULL, ("td is NULL"));
1699 if (kev->ident > INT_MAX)
1700 error = EBADF;
1701 else
1702 error = fget(td, kev->ident, &cap_event_rights, &fp);
1703 if (error)
1704 goto done;
1705
1706 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
1707 kev->ident, M_NOWAIT) != 0) {
1708 /* try again */
1709 fdrop(fp, td);
1710 fp = NULL;
1711 error = kqueue_expand(kq, fops, kev->ident, mflag);
1712 if (error)
1713 goto done;
1714 goto findkn;
1715 }
1716
1717 if (fp->f_type == DTYPE_KQUEUE) {
1718 /*
1719 * If we add some intelligence about what we are doing,
1720 * we should be able to support events on ourselves.
1721 * We need to know when we are doing this to prevent
1722 * getting both the knlist lock and the kq lock since
1723 * they are the same thing.
1724 */
1725 if (fp->f_data == kq) {
1726 error = EINVAL;
1727 goto done;
1728 }
1729
1730 /*
1731 * Pre-lock the filedesc before the global
1732 * lock mutex, see the comment in
1733 * kqueue_close().
1734 */
1735 FILEDESC_XLOCK(td->td_proc->p_fd);
1736 filedesc_unlock = 1;
1737 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
1738 }
1739
1740 KQ_LOCK(kq);
1741 if (kev->ident < kq->kq_knlistsize) {
1742 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) {
1743 MPASS(kn->kn_kq == kq);
1744 if (kev->filter == kn->kn_filter)
1745 break;
1746 }
1747 }
1748 } else {
1749 if ((kev->flags & EV_ADD) == EV_ADD) {
1750 error = kqueue_expand(kq, fops, kev->ident, mflag);
1751 if (error != 0)
1752 goto done;
1753 }
1754
1755 KQ_LOCK(kq);
1756
1757 /*
1758 * If possible, find an existing knote to use for this kevent.
1759 */
1760 if (kev->filter == EVFILT_PROC &&
1761 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) {
1762 /* This is an internal creation of a process tracking
1763 * note. Don't attempt to coalesce this with an
1764 * existing note.
1765 */
1766 ;
1767 } else if (kq->kq_knhashmask != 0) {
1768 struct klist *list;
1769
1770 list = &kq->kq_knhash[
1771 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
1772 SLIST_FOREACH(kn, list, kn_link) {
1773 MPASS(kn->kn_kq == kq);
1774 if (kev->ident == kn->kn_id &&
1775 kev->filter == kn->kn_filter)
1776 break;
1777 }
1778 }
1779 }
1780
1781 /* knote is in the process of changing, wait for it to stabilize. */
1782 if (kn != NULL && kn_in_flux(kn)) {
1783 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1784 if (filedesc_unlock) {
1785 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1786 filedesc_unlock = 0;
1787 }
1788 kq->kq_state |= KQ_FLUXWAIT;
1789 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
1790 if (fp != NULL) {
1791 fdrop(fp, td);
1792 fp = NULL;
1793 }
1794 goto findkn;
1795 }
1796
1797 /*
1798 * kn now contains the matching knote, or NULL if no match
1799 */
1800 if (kn == NULL) {
1801 if (kev->flags & EV_ADD) {
1802 kn = tkn;
1803 tkn = NULL;
1804 if (kn == NULL) {
1805 KQ_UNLOCK(kq);
1806 error = ENOMEM;
1807 goto done;
1808 }
1809
1810 /*
1811 * Now that the kqueue is locked, make sure the fd
1812 * didn't change out from under us.
1813 */
1814 if (fops->f_isfd &&
1815 fget_noref_unlocked(td->td_proc->p_fd,
1816 kev->ident) != fp) {
1817 KQ_UNLOCK(kq);
1818 tkn = kn;
1819 error = EBADF;
1820 goto done;
1821 }
1822 kn->kn_fp = fp;
1823 kn->kn_kq = kq;
1824 kn->kn_fop = fops;
1825 /*
1826 * apply reference counts to knote structure, and
1827 * do not release it at the end of this routine.
1828 */
1829 fops = NULL;
1830 fp = NULL;
1831
1832 kn->kn_sfflags = kev->fflags;
1833 kn->kn_sdata = kev->data;
1834 kev->fflags = 0;
1835 kev->data = 0;
1836 kn->kn_kevent = *kev;
1837 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
1838 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT);
1839 kn->kn_status = KN_DETACHED;
1840 if ((kev->flags & EV_DISABLE) != 0)
1841 kn->kn_status |= KN_DISABLED;
1842 kn_enter_flux(kn);
1843
1844 error = knote_attach(kn, kq);
1845 KQ_UNLOCK(kq);
1846 if (error != 0) {
1847 tkn = kn;
1848 goto done;
1849 }
1850
1851 if ((error = kn->kn_fop->f_attach(kn)) != 0) {
1852 knote_drop_detached(kn, td);
1853 goto done;
1854 }
1855 knl = kn_list_lock(kn);
1856 goto done_ev_add;
1857 } else {
1858 /* No matching knote and the EV_ADD flag is not set. */
1859 KQ_UNLOCK(kq);
1860 error = ENOENT;
1861 goto done;
1862 }
1863 }
1864
1865 if (kev->flags & EV_DELETE) {
1866 kn_enter_flux(kn);
1867 KQ_UNLOCK(kq);
1868 knote_drop(kn, td);
1869 goto done;
1870 }
1871
1872 if (kev->flags & EV_FORCEONESHOT) {
1873 kn->kn_flags |= EV_ONESHOT;
1874 KNOTE_ACTIVATE(kn, 1);
1875 }
1876
1877 if ((kev->flags & EV_ENABLE) != 0)
1878 kn->kn_status &= ~KN_DISABLED;
1879 else if ((kev->flags & EV_DISABLE) != 0)
1880 kn->kn_status |= KN_DISABLED;
1881
1882 /*
1883 * The user may change some filter values after the initial EV_ADD,
1884 * but doing so will not reset any filter which has already been
1885 * triggered.
1886 */
1887 kn->kn_status |= KN_SCAN;
1888 kn_enter_flux(kn);
1889 KQ_UNLOCK(kq);
1890 knl = kn_list_lock(kn);
1891 if ((kev->flags & EV_KEEPUDATA) == 0)
1892 kn->kn_kevent.udata = kev->udata;
1893 if (!fops->f_isfd && fops->f_touch != NULL) {
1894 fops->f_touch(kn, kev, EVENT_REGISTER);
1895 } else {
1896 kn->kn_sfflags = kev->fflags;
1897 kn->kn_sdata = kev->data;
1898 }
1899
1900 done_ev_add:
1901 /*
1902 * We can get here with kn->kn_knlist == NULL. This can happen when
1903 * the initial attach event decides that the event is "completed"
1904 * already, e.g., filt_procattach() is called on a zombie process. It
1905 * will call filt_proc() which will remove it from the list, and NULL
1906 * kn_knlist.
1907 *
1908 * KN_DISABLED will be stable while the knote is in flux, so the
1909 * unlocked read will not race with an update.
1910 */
1911 if ((kn->kn_status & KN_DISABLED) == 0)
1912 event = kn->kn_fop->f_event(kn, 0);
1913 else
1914 event = 0;
1915
1916 KQ_LOCK(kq);
1917 if (event)
1918 kn->kn_status |= KN_ACTIVE;
1919 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) ==
1920 KN_ACTIVE)
1921 knote_enqueue(kn);
1922 kn->kn_status &= ~KN_SCAN;
1923 kn_leave_flux(kn);
1924 kn_list_unlock(knl);
1925 KQ_UNLOCK_FLUX(kq);
1926
1927 done:
1928 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
1929 if (filedesc_unlock)
1930 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1931 if (fp != NULL)
1932 fdrop(fp, td);
1933 knote_free(tkn);
1934 if (fops != NULL)
1935 kqueue_fo_release(filt);
1936 return (error);
1937 }
1938
1939 static int
kqueue_acquire_ref(struct kqueue * kq)1940 kqueue_acquire_ref(struct kqueue *kq)
1941 {
1942 KQ_LOCK(kq);
1943 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
1944 KQ_UNLOCK(kq);
1945 return (EBADF);
1946 }
1947 kq->kq_refcnt++;
1948 KQ_UNLOCK(kq);
1949 return (0);
1950 }
1951
1952 static int
kqueue_acquire(struct file * fp,struct kqueue ** kqp)1953 kqueue_acquire(struct file *fp, struct kqueue **kqp)
1954 {
1955 struct kqueue *kq;
1956 int error;
1957
1958 kq = fp->f_data;
1959 if (fp->f_type != DTYPE_KQUEUE || kq == NULL)
1960 return (EINVAL);
1961 error = kqueue_acquire_ref(kq);
1962 if (error == 0)
1963 *kqp = kq;
1964 return (error);
1965 }
1966
1967 static void
kqueue_release(struct kqueue * kq,int locked)1968 kqueue_release(struct kqueue *kq, int locked)
1969 {
1970 if (locked)
1971 KQ_OWNED(kq);
1972 else
1973 KQ_LOCK(kq);
1974 kq->kq_refcnt--;
1975 if (kq->kq_refcnt == 1)
1976 wakeup(&kq->kq_refcnt);
1977 if (!locked)
1978 KQ_UNLOCK(kq);
1979 }
1980
1981 static void
ast_kqueue(struct thread * td,int tda __unused)1982 ast_kqueue(struct thread *td, int tda __unused)
1983 {
1984 taskqueue_quiesce(taskqueue_kqueue_ctx);
1985 }
1986
1987 static void
kqueue_schedtask(struct kqueue * kq)1988 kqueue_schedtask(struct kqueue *kq)
1989 {
1990 KQ_OWNED(kq);
1991 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
1992 ("scheduling kqueue task while draining"));
1993
1994 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
1995 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task);
1996 kq->kq_state |= KQ_TASKSCHED;
1997 ast_sched(curthread, TDA_KQUEUE);
1998 }
1999 }
2000
2001 /*
2002 * Expand the kq to make sure we have storage for fops/ident pair.
2003 *
2004 * Return 0 on success (or no work necessary), return errno on failure.
2005 */
2006 static int
kqueue_expand(struct kqueue * kq,const struct filterops * fops,uintptr_t ident,int mflag)2007 kqueue_expand(struct kqueue *kq, const struct filterops *fops, uintptr_t ident,
2008 int mflag)
2009 {
2010 struct klist *list, *tmp_knhash, *to_free;
2011 u_long tmp_knhashmask;
2012 int error, fd, size;
2013
2014 KQ_NOTOWNED(kq);
2015
2016 error = 0;
2017 to_free = NULL;
2018 if (fops->f_isfd) {
2019 fd = ident;
2020 size = atomic_load_int(&kq->kq_knlistsize);
2021 if (size <= fd) {
2022 do {
2023 size += KQEXTENT;
2024 } while (size <= fd);
2025 list = malloc(size * sizeof(*list), M_KQUEUE, mflag);
2026 if (list == NULL)
2027 return ENOMEM;
2028 KQ_LOCK(kq);
2029 if ((kq->kq_state & KQ_CLOSING) != 0) {
2030 to_free = list;
2031 error = EBADF;
2032 } else if (kq->kq_knlistsize >= size) {
2033 to_free = list;
2034 } else {
2035 if (kq->kq_knlist != NULL) {
2036 bcopy(kq->kq_knlist, list,
2037 kq->kq_knlistsize * sizeof(*list));
2038 to_free = kq->kq_knlist;
2039 kq->kq_knlist = NULL;
2040 }
2041 bzero((caddr_t)list +
2042 kq->kq_knlistsize * sizeof(*list),
2043 (size - kq->kq_knlistsize) * sizeof(*list));
2044 kq->kq_knlistsize = size;
2045 kq->kq_knlist = list;
2046 }
2047 MPASS(error != 0 || kq->kq_knlistsize > fd);
2048 KQ_UNLOCK(kq);
2049 }
2050 } else {
2051 if (kq->kq_knhashmask == 0) {
2052 tmp_knhash = hashinit_flags(KN_HASHSIZE, M_KQUEUE,
2053 &tmp_knhashmask, (mflag & M_WAITOK) != 0 ?
2054 HASH_WAITOK : HASH_NOWAIT);
2055 if (tmp_knhash == NULL)
2056 return (ENOMEM);
2057 KQ_LOCK(kq);
2058 if ((kq->kq_state & KQ_CLOSING) != 0) {
2059 to_free = tmp_knhash;
2060 error = EBADF;
2061 } else if (kq->kq_knhashmask == 0) {
2062 kq->kq_knhash = tmp_knhash;
2063 kq->kq_knhashmask = tmp_knhashmask;
2064 } else {
2065 to_free = tmp_knhash;
2066 }
2067 KQ_UNLOCK(kq);
2068 }
2069 }
2070 free(to_free, M_KQUEUE);
2071
2072 KQ_NOTOWNED(kq);
2073 return (error);
2074 }
2075
2076 static void
kqueue_task(void * arg,int pending)2077 kqueue_task(void *arg, int pending)
2078 {
2079 struct kqueue *kq;
2080 int haskqglobal;
2081
2082 haskqglobal = 0;
2083 kq = arg;
2084
2085 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
2086 KQ_LOCK(kq);
2087
2088 KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
2089
2090 kq->kq_state &= ~KQ_TASKSCHED;
2091 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
2092 wakeup(&kq->kq_state);
2093 }
2094 KQ_UNLOCK(kq);
2095 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
2096 }
2097
2098 /*
2099 * Scan, update kn_data (if not ONESHOT), and copyout triggered events.
2100 * We treat KN_MARKER knotes as if they are in flux.
2101 */
2102 static int
kqueue_scan(struct kqueue * kq,int maxevents,struct kevent_copyops * k_ops,const struct timespec * tsp,struct kevent * keva,struct thread * td)2103 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
2104 const struct timespec *tsp, struct kevent *keva, struct thread *td)
2105 {
2106 struct kevent *kevp;
2107 struct knote *kn, *marker;
2108 struct knlist *knl;
2109 sbintime_t asbt, rsbt;
2110 int count, error, haskqglobal, influx, nkev, touch;
2111
2112 count = maxevents;
2113 nkev = 0;
2114 error = 0;
2115 haskqglobal = 0;
2116
2117 if (maxevents == 0)
2118 goto done_nl;
2119 if (maxevents < 0) {
2120 error = EINVAL;
2121 goto done_nl;
2122 }
2123
2124 rsbt = 0;
2125 if (tsp != NULL) {
2126 if (!timespecvalid_interval(tsp)) {
2127 error = EINVAL;
2128 goto done_nl;
2129 }
2130 if (timespecisset(tsp)) {
2131 if (tsp->tv_sec <= INT32_MAX) {
2132 rsbt = tstosbt(*tsp);
2133 if (TIMESEL(&asbt, rsbt))
2134 asbt += tc_tick_sbt;
2135 if (asbt <= SBT_MAX - rsbt)
2136 asbt += rsbt;
2137 else
2138 asbt = 0;
2139 rsbt >>= tc_precexp;
2140 } else
2141 asbt = 0;
2142 } else
2143 asbt = -1;
2144 } else
2145 asbt = 0;
2146 marker = knote_alloc(M_WAITOK);
2147 marker->kn_status = KN_MARKER;
2148 KQ_LOCK(kq);
2149
2150 retry:
2151 kevp = keva;
2152 if (kq->kq_count == 0) {
2153 if (asbt == -1) {
2154 error = EWOULDBLOCK;
2155 } else {
2156 kq->kq_state |= KQ_SLEEP;
2157 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH,
2158 "kqread", asbt, rsbt, C_ABSOLUTE);
2159 }
2160 if (error == 0)
2161 goto retry;
2162 /* don't restart after signals... */
2163 if (error == ERESTART)
2164 error = EINTR;
2165 else if (error == EWOULDBLOCK)
2166 error = 0;
2167 goto done;
2168 }
2169
2170 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
2171 influx = 0;
2172 while (count) {
2173 KQ_OWNED(kq);
2174 kn = TAILQ_FIRST(&kq->kq_head);
2175
2176 if ((kn->kn_status == KN_MARKER && kn != marker) ||
2177 kn_in_flux(kn)) {
2178 if (influx) {
2179 influx = 0;
2180 KQ_FLUX_WAKEUP(kq);
2181 }
2182 kq->kq_state |= KQ_FLUXWAIT;
2183 error = msleep(kq, &kq->kq_lock, PSOCK,
2184 "kqflxwt", 0);
2185 continue;
2186 }
2187
2188 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
2189 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
2190 kn->kn_status &= ~KN_QUEUED;
2191 kq->kq_count--;
2192 continue;
2193 }
2194 if (kn == marker) {
2195 KQ_FLUX_WAKEUP(kq);
2196 if (count == maxevents)
2197 goto retry;
2198 goto done;
2199 }
2200 KASSERT(!kn_in_flux(kn),
2201 ("knote %p is unexpectedly in flux", kn));
2202
2203 if ((kn->kn_flags & EV_DROP) == EV_DROP) {
2204 kn->kn_status &= ~KN_QUEUED;
2205 kn_enter_flux(kn);
2206 kq->kq_count--;
2207 KQ_UNLOCK(kq);
2208 /*
2209 * We don't need to lock the list since we've
2210 * marked it as in flux.
2211 */
2212 knote_drop(kn, td);
2213 KQ_LOCK(kq);
2214 continue;
2215 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
2216 kn->kn_status &= ~KN_QUEUED;
2217 kn_enter_flux(kn);
2218 kq->kq_count--;
2219 KQ_UNLOCK(kq);
2220 /*
2221 * We don't need to lock the list since we've
2222 * marked the knote as being in flux.
2223 */
2224 *kevp = kn->kn_kevent;
2225 knote_drop(kn, td);
2226 KQ_LOCK(kq);
2227 kn = NULL;
2228 } else {
2229 kn->kn_status |= KN_SCAN;
2230 kn_enter_flux(kn);
2231 KQ_UNLOCK(kq);
2232 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
2233 KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
2234 knl = kn_list_lock(kn);
2235 if (kn->kn_fop->f_event(kn, 0) == 0) {
2236 KQ_LOCK(kq);
2237 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
2238 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE |
2239 KN_SCAN);
2240 kn_leave_flux(kn);
2241 kq->kq_count--;
2242 kn_list_unlock(knl);
2243 influx = 1;
2244 continue;
2245 }
2246 touch = (!kn->kn_fop->f_isfd &&
2247 kn->kn_fop->f_touch != NULL);
2248 if (touch)
2249 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS);
2250 else
2251 *kevp = kn->kn_kevent;
2252 KQ_LOCK(kq);
2253 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
2254 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
2255 /*
2256 * Manually clear knotes who weren't
2257 * 'touch'ed.
2258 */
2259 if (touch == 0 && kn->kn_flags & EV_CLEAR) {
2260 kn->kn_data = 0;
2261 kn->kn_fflags = 0;
2262 }
2263 if (kn->kn_flags & EV_DISPATCH)
2264 kn->kn_status |= KN_DISABLED;
2265 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
2266 kq->kq_count--;
2267 } else
2268 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
2269
2270 kn->kn_status &= ~KN_SCAN;
2271 kn_leave_flux(kn);
2272 kn_list_unlock(knl);
2273 influx = 1;
2274 }
2275
2276 /* we are returning a copy to the user */
2277 kevp++;
2278 nkev++;
2279 count--;
2280
2281 if (nkev == KQ_NEVENTS) {
2282 influx = 0;
2283 KQ_UNLOCK_FLUX(kq);
2284 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
2285 nkev = 0;
2286 kevp = keva;
2287 KQ_LOCK(kq);
2288 if (error)
2289 break;
2290 }
2291 }
2292 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
2293 done:
2294 KQ_OWNED(kq);
2295 KQ_UNLOCK_FLUX(kq);
2296 knote_free(marker);
2297 done_nl:
2298 KQ_NOTOWNED(kq);
2299 if (nkev != 0)
2300 error = k_ops->k_copyout(k_ops->arg, keva, nkev);
2301 td->td_retval[0] = maxevents - count;
2302 return (error);
2303 }
2304
2305 /*ARGSUSED*/
2306 static int
kqueue_ioctl(struct file * fp,u_long cmd,void * data,struct ucred * active_cred,struct thread * td)2307 kqueue_ioctl(struct file *fp, u_long cmd, void *data,
2308 struct ucred *active_cred, struct thread *td)
2309 {
2310 /*
2311 * Enabling sigio causes two major problems:
2312 * 1) infinite recursion:
2313 * Synopsys: kevent is being used to track signals and have FIOASYNC
2314 * set. On receipt of a signal this will cause a kqueue to recurse
2315 * into itself over and over. Sending the sigio causes the kqueue
2316 * to become ready, which in turn posts sigio again, forever.
2317 * Solution: this can be solved by setting a flag in the kqueue that
2318 * we have a SIGIO in progress.
2319 * 2) locking problems:
2320 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
2321 * us above the proc and pgrp locks.
2322 * Solution: Post a signal using an async mechanism, being sure to
2323 * record a generation count in the delivery so that we do not deliver
2324 * a signal to the wrong process.
2325 *
2326 * Note, these two mechanisms are somewhat mutually exclusive!
2327 */
2328 #if 0
2329 struct kqueue *kq;
2330
2331 kq = fp->f_data;
2332 switch (cmd) {
2333 case FIOASYNC:
2334 if (*(int *)data) {
2335 kq->kq_state |= KQ_ASYNC;
2336 } else {
2337 kq->kq_state &= ~KQ_ASYNC;
2338 }
2339 return (0);
2340
2341 case FIOSETOWN:
2342 return (fsetown(*(int *)data, &kq->kq_sigio));
2343
2344 case FIOGETOWN:
2345 *(int *)data = fgetown(&kq->kq_sigio);
2346 return (0);
2347 }
2348 #endif
2349
2350 return (ENOTTY);
2351 }
2352
2353 /*ARGSUSED*/
2354 static int
kqueue_poll(struct file * fp,int events,struct ucred * active_cred,struct thread * td)2355 kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
2356 struct thread *td)
2357 {
2358 struct kqueue *kq;
2359 int revents = 0;
2360 int error;
2361
2362 if ((error = kqueue_acquire(fp, &kq)))
2363 return POLLERR;
2364
2365 KQ_LOCK(kq);
2366 if (events & (POLLIN | POLLRDNORM)) {
2367 if (kq->kq_count) {
2368 revents |= events & (POLLIN | POLLRDNORM);
2369 } else {
2370 selrecord(td, &kq->kq_sel);
2371 if (SEL_WAITING(&kq->kq_sel))
2372 kq->kq_state |= KQ_SEL;
2373 }
2374 }
2375 kqueue_release(kq, 1);
2376 KQ_UNLOCK(kq);
2377 return (revents);
2378 }
2379
2380 /*ARGSUSED*/
2381 static int
kqueue_stat(struct file * fp,struct stat * st,struct ucred * active_cred)2382 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred)
2383 {
2384
2385 bzero((void *)st, sizeof *st);
2386 /*
2387 * We no longer return kq_count because the unlocked value is useless.
2388 * If you spent all this time getting the count, why not spend your
2389 * syscall better by calling kevent?
2390 *
2391 * XXX - This is needed for libc_r.
2392 */
2393 st->st_mode = S_IFIFO;
2394 return (0);
2395 }
2396
2397 static void
kqueue_drain(struct kqueue * kq,struct thread * td)2398 kqueue_drain(struct kqueue *kq, struct thread *td)
2399 {
2400 struct knote *kn;
2401 int i;
2402
2403 KQ_LOCK(kq);
2404
2405 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
2406 ("kqueue already closing"));
2407 kq->kq_state |= KQ_CLOSING;
2408 if (kq->kq_refcnt > 1)
2409 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
2410
2411 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
2412
2413 KASSERT(knlist_empty(&kq->kq_sel.si_note),
2414 ("kqueue's knlist not empty"));
2415
2416 for (i = 0; i < kq->kq_knlistsize; i++) {
2417 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
2418 if (kn_in_flux(kn)) {
2419 kq->kq_state |= KQ_FLUXWAIT;
2420 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
2421 continue;
2422 }
2423 kn_enter_flux(kn);
2424 KQ_UNLOCK(kq);
2425 knote_drop(kn, td);
2426 KQ_LOCK(kq);
2427 }
2428 }
2429 if (kq->kq_knhashmask != 0) {
2430 for (i = 0; i <= kq->kq_knhashmask; i++) {
2431 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
2432 if (kn_in_flux(kn)) {
2433 kq->kq_state |= KQ_FLUXWAIT;
2434 msleep(kq, &kq->kq_lock, PSOCK,
2435 "kqclo2", 0);
2436 continue;
2437 }
2438 kn_enter_flux(kn);
2439 KQ_UNLOCK(kq);
2440 knote_drop(kn, td);
2441 KQ_LOCK(kq);
2442 }
2443 }
2444 }
2445
2446 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
2447 kq->kq_state |= KQ_TASKDRAIN;
2448 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
2449 }
2450
2451 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
2452 selwakeuppri(&kq->kq_sel, PSOCK);
2453 if (!SEL_WAITING(&kq->kq_sel))
2454 kq->kq_state &= ~KQ_SEL;
2455 }
2456
2457 KQ_UNLOCK(kq);
2458 }
2459
2460 static void
kqueue_destroy(struct kqueue * kq)2461 kqueue_destroy(struct kqueue *kq)
2462 {
2463
2464 KASSERT(kq->kq_fdp == NULL,
2465 ("kqueue still attached to a file descriptor"));
2466 seldrain(&kq->kq_sel);
2467 knlist_destroy(&kq->kq_sel.si_note);
2468 mtx_destroy(&kq->kq_lock);
2469
2470 if (kq->kq_knhash != NULL)
2471 free(kq->kq_knhash, M_KQUEUE);
2472 if (kq->kq_knlist != NULL)
2473 free(kq->kq_knlist, M_KQUEUE);
2474
2475 funsetown(&kq->kq_sigio);
2476 }
2477
2478 /*ARGSUSED*/
2479 static int
kqueue_close(struct file * fp,struct thread * td)2480 kqueue_close(struct file *fp, struct thread *td)
2481 {
2482 struct kqueue *kq = fp->f_data;
2483 struct filedesc *fdp;
2484 int error;
2485 int filedesc_unlock;
2486
2487 if ((error = kqueue_acquire(fp, &kq)))
2488 return error;
2489 kqueue_drain(kq, td);
2490
2491 /*
2492 * We could be called due to the knote_drop() doing fdrop(),
2493 * called from kqueue_register(). In this case the global
2494 * lock is owned, and filedesc sx is locked before, to not
2495 * take the sleepable lock after non-sleepable.
2496 */
2497 fdp = kq->kq_fdp;
2498 kq->kq_fdp = NULL;
2499 if (!sx_xlocked(FILEDESC_LOCK(fdp))) {
2500 FILEDESC_XLOCK(fdp);
2501 filedesc_unlock = 1;
2502 } else
2503 filedesc_unlock = 0;
2504 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list);
2505 if (filedesc_unlock)
2506 FILEDESC_XUNLOCK(fdp);
2507
2508 kqueue_destroy(kq);
2509 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0);
2510 crfree(kq->kq_cred);
2511 free(kq, M_KQUEUE);
2512 fp->f_data = NULL;
2513
2514 return (0);
2515 }
2516
2517 static int
kqueue_fill_kinfo(struct file * fp,struct kinfo_file * kif,struct filedesc * fdp)2518 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
2519 {
2520 struct kqueue *kq = fp->f_data;
2521
2522 kif->kf_type = KF_TYPE_KQUEUE;
2523 kif->kf_un.kf_kqueue.kf_kqueue_addr = (uintptr_t)kq;
2524 kif->kf_un.kf_kqueue.kf_kqueue_count = kq->kq_count;
2525 kif->kf_un.kf_kqueue.kf_kqueue_state = kq->kq_state;
2526 return (0);
2527 }
2528
2529 static void
kqueue_wakeup(struct kqueue * kq)2530 kqueue_wakeup(struct kqueue *kq)
2531 {
2532 KQ_OWNED(kq);
2533
2534 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
2535 kq->kq_state &= ~KQ_SLEEP;
2536 wakeup(kq);
2537 }
2538 if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
2539 selwakeuppri(&kq->kq_sel, PSOCK);
2540 if (!SEL_WAITING(&kq->kq_sel))
2541 kq->kq_state &= ~KQ_SEL;
2542 }
2543 if (!knlist_empty(&kq->kq_sel.si_note))
2544 kqueue_schedtask(kq);
2545 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
2546 pgsigio(&kq->kq_sigio, SIGIO, 0);
2547 }
2548 }
2549
2550 /*
2551 * Walk down a list of knotes, activating them if their event has triggered.
2552 *
2553 * There is a possibility to optimize in the case of one kq watching another.
2554 * Instead of scheduling a task to wake it up, you could pass enough state
2555 * down the chain to make up the parent kqueue. Make this code functional
2556 * first.
2557 */
2558 void
knote(struct knlist * list,long hint,int lockflags)2559 knote(struct knlist *list, long hint, int lockflags)
2560 {
2561 struct kqueue *kq;
2562 struct knote *kn, *tkn;
2563 int error;
2564
2565 if (list == NULL)
2566 return;
2567
2568 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
2569
2570 if ((lockflags & KNF_LISTLOCKED) == 0)
2571 list->kl_lock(list->kl_lockarg);
2572
2573 /*
2574 * If we unlock the list lock (and enter influx), we can
2575 * eliminate the kqueue scheduling, but this will introduce
2576 * four lock/unlock's for each knote to test. Also, marker
2577 * would be needed to keep iteration position, since filters
2578 * or other threads could remove events.
2579 */
2580 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) {
2581 kq = kn->kn_kq;
2582 KQ_LOCK(kq);
2583 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) {
2584 /*
2585 * Do not process the influx notes, except for
2586 * the influx coming from the kq unlock in the
2587 * kqueue_scan(). In the later case, we do
2588 * not interfere with the scan, since the code
2589 * fragment in kqueue_scan() locks the knlist,
2590 * and cannot proceed until we finished.
2591 */
2592 KQ_UNLOCK(kq);
2593 } else if ((lockflags & KNF_NOKQLOCK) != 0) {
2594 kn_enter_flux(kn);
2595 KQ_UNLOCK(kq);
2596 error = kn->kn_fop->f_event(kn, hint);
2597 KQ_LOCK(kq);
2598 kn_leave_flux(kn);
2599 if (error)
2600 KNOTE_ACTIVATE(kn, 1);
2601 KQ_UNLOCK_FLUX(kq);
2602 } else {
2603 if (kn->kn_fop->f_event(kn, hint))
2604 KNOTE_ACTIVATE(kn, 1);
2605 KQ_UNLOCK(kq);
2606 }
2607 }
2608 if ((lockflags & KNF_LISTLOCKED) == 0)
2609 list->kl_unlock(list->kl_lockarg);
2610 }
2611
2612 /*
2613 * add a knote to a knlist
2614 */
2615 void
knlist_add(struct knlist * knl,struct knote * kn,int islocked)2616 knlist_add(struct knlist *knl, struct knote *kn, int islocked)
2617 {
2618
2619 KNL_ASSERT_LOCK(knl, islocked);
2620 KQ_NOTOWNED(kn->kn_kq);
2621 KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn));
2622 KASSERT((kn->kn_status & KN_DETACHED) != 0,
2623 ("knote %p was not detached", kn));
2624 KASSERT(kn->kn_knlist == NULL,
2625 ("knote %p was already on knlist %p", kn, kn->kn_knlist));
2626 if (!islocked)
2627 knl->kl_lock(knl->kl_lockarg);
2628 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext);
2629 if (!islocked)
2630 knl->kl_unlock(knl->kl_lockarg);
2631 KQ_LOCK(kn->kn_kq);
2632 kn->kn_knlist = knl;
2633 kn->kn_status &= ~KN_DETACHED;
2634 KQ_UNLOCK(kn->kn_kq);
2635 }
2636
2637 static void
knlist_remove_kq(struct knlist * knl,struct knote * kn,int knlislocked,int kqislocked)2638 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked,
2639 int kqislocked)
2640 {
2641
2642 KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked"));
2643 KNL_ASSERT_LOCK(knl, knlislocked);
2644 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED);
2645 KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn));
2646 KASSERT((kn->kn_status & KN_DETACHED) == 0,
2647 ("knote %p was already detached", kn));
2648 KASSERT(kn->kn_knlist == knl,
2649 ("knote %p was not on knlist %p", kn, knl));
2650 if (!knlislocked)
2651 knl->kl_lock(knl->kl_lockarg);
2652 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
2653 kn->kn_knlist = NULL;
2654 if (!knlislocked)
2655 kn_list_unlock(knl);
2656 if (!kqislocked)
2657 KQ_LOCK(kn->kn_kq);
2658 kn->kn_status |= KN_DETACHED;
2659 if (!kqislocked)
2660 KQ_UNLOCK(kn->kn_kq);
2661 }
2662
2663 /*
2664 * remove knote from the specified knlist
2665 */
2666 void
knlist_remove(struct knlist * knl,struct knote * kn,int islocked)2667 knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
2668 {
2669
2670 knlist_remove_kq(knl, kn, islocked, 0);
2671 }
2672
2673 int
knlist_empty(struct knlist * knl)2674 knlist_empty(struct knlist *knl)
2675 {
2676
2677 KNL_ASSERT_LOCKED(knl);
2678 return (SLIST_EMPTY(&knl->kl_list));
2679 }
2680
2681 static struct mtx knlist_lock;
2682 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects",
2683 MTX_DEF);
2684 static void knlist_mtx_lock(void *arg);
2685 static void knlist_mtx_unlock(void *arg);
2686
2687 static void
knlist_mtx_lock(void * arg)2688 knlist_mtx_lock(void *arg)
2689 {
2690
2691 mtx_lock((struct mtx *)arg);
2692 }
2693
2694 static void
knlist_mtx_unlock(void * arg)2695 knlist_mtx_unlock(void *arg)
2696 {
2697
2698 mtx_unlock((struct mtx *)arg);
2699 }
2700
2701 static void
knlist_mtx_assert_lock(void * arg,int what)2702 knlist_mtx_assert_lock(void *arg, int what)
2703 {
2704
2705 if (what == LA_LOCKED)
2706 mtx_assert((struct mtx *)arg, MA_OWNED);
2707 else
2708 mtx_assert((struct mtx *)arg, MA_NOTOWNED);
2709 }
2710
2711 void
knlist_init(struct knlist * knl,void * lock,void (* kl_lock)(void *),void (* kl_unlock)(void *),void (* kl_assert_lock)(void *,int))2712 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
2713 void (*kl_unlock)(void *),
2714 void (*kl_assert_lock)(void *, int))
2715 {
2716
2717 if (lock == NULL)
2718 knl->kl_lockarg = &knlist_lock;
2719 else
2720 knl->kl_lockarg = lock;
2721
2722 if (kl_lock == NULL)
2723 knl->kl_lock = knlist_mtx_lock;
2724 else
2725 knl->kl_lock = kl_lock;
2726 if (kl_unlock == NULL)
2727 knl->kl_unlock = knlist_mtx_unlock;
2728 else
2729 knl->kl_unlock = kl_unlock;
2730 if (kl_assert_lock == NULL)
2731 knl->kl_assert_lock = knlist_mtx_assert_lock;
2732 else
2733 knl->kl_assert_lock = kl_assert_lock;
2734
2735 knl->kl_autodestroy = 0;
2736 SLIST_INIT(&knl->kl_list);
2737 }
2738
2739 void
knlist_init_mtx(struct knlist * knl,struct mtx * lock)2740 knlist_init_mtx(struct knlist *knl, struct mtx *lock)
2741 {
2742
2743 knlist_init(knl, lock, NULL, NULL, NULL);
2744 }
2745
2746 struct knlist *
knlist_alloc(struct mtx * lock)2747 knlist_alloc(struct mtx *lock)
2748 {
2749 struct knlist *knl;
2750
2751 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK);
2752 knlist_init_mtx(knl, lock);
2753 return (knl);
2754 }
2755
2756 void
knlist_destroy(struct knlist * knl)2757 knlist_destroy(struct knlist *knl)
2758 {
2759
2760 KASSERT(KNLIST_EMPTY(knl),
2761 ("destroying knlist %p with knotes on it", knl));
2762 }
2763
2764 void
knlist_detach(struct knlist * knl)2765 knlist_detach(struct knlist *knl)
2766 {
2767
2768 KNL_ASSERT_LOCKED(knl);
2769 knl->kl_autodestroy = 1;
2770 if (knlist_empty(knl)) {
2771 knlist_destroy(knl);
2772 free(knl, M_KQUEUE);
2773 }
2774 }
2775
2776 /*
2777 * Even if we are locked, we may need to drop the lock to allow any influx
2778 * knotes time to "settle".
2779 */
2780 void
knlist_cleardel(struct knlist * knl,struct thread * td,int islocked,int killkn)2781 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
2782 {
2783 struct knote *kn, *kn2;
2784 struct kqueue *kq;
2785
2786 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl));
2787 if (islocked)
2788 KNL_ASSERT_LOCKED(knl);
2789 else {
2790 KNL_ASSERT_UNLOCKED(knl);
2791 again: /* need to reacquire lock since we have dropped it */
2792 knl->kl_lock(knl->kl_lockarg);
2793 }
2794
2795 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
2796 kq = kn->kn_kq;
2797 KQ_LOCK(kq);
2798 if (kn_in_flux(kn)) {
2799 KQ_UNLOCK(kq);
2800 continue;
2801 }
2802 knlist_remove_kq(knl, kn, 1, 1);
2803 if (killkn) {
2804 kn_enter_flux(kn);
2805 KQ_UNLOCK(kq);
2806 knote_drop_detached(kn, td);
2807 } else {
2808 /* Make sure cleared knotes disappear soon */
2809 kn->kn_flags |= EV_EOF | EV_ONESHOT;
2810 KQ_UNLOCK(kq);
2811 }
2812 kq = NULL;
2813 }
2814
2815 if (!SLIST_EMPTY(&knl->kl_list)) {
2816 /* there are still in flux knotes remaining */
2817 kn = SLIST_FIRST(&knl->kl_list);
2818 kq = kn->kn_kq;
2819 KQ_LOCK(kq);
2820 KASSERT(kn_in_flux(kn), ("knote removed w/o list lock"));
2821 knl->kl_unlock(knl->kl_lockarg);
2822 kq->kq_state |= KQ_FLUXWAIT;
2823 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
2824 kq = NULL;
2825 goto again;
2826 }
2827
2828 if (islocked)
2829 KNL_ASSERT_LOCKED(knl);
2830 else {
2831 knl->kl_unlock(knl->kl_lockarg);
2832 KNL_ASSERT_UNLOCKED(knl);
2833 }
2834 }
2835
2836 /*
2837 * Remove all knotes referencing a specified fd must be called with FILEDESC
2838 * lock. This prevents a race where a new fd comes along and occupies the
2839 * entry and we attach a knote to the fd.
2840 */
2841 void
knote_fdclose(struct thread * td,int fd)2842 knote_fdclose(struct thread *td, int fd)
2843 {
2844 struct filedesc *fdp = td->td_proc->p_fd;
2845 struct kqueue *kq;
2846 struct knote *kn;
2847
2848 FILEDESC_XLOCK_ASSERT(fdp);
2849
2850 /*
2851 * We shouldn't have to worry about new kevents appearing on fd
2852 * since filedesc is locked.
2853 */
2854 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
2855 KQ_LOCK(kq);
2856 if (kq->kq_knlistsize <= fd ||
2857 SLIST_EMPTY(&kq->kq_knlist[fd])) {
2858 KQ_UNLOCK(kq);
2859 continue;
2860 }
2861
2862 while ((kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
2863 if (kn_in_flux(kn)) {
2864 /*
2865 * Wait for this knote to stabilize, it could be
2866 * the case that it's in the process of being
2867 * dropped anyways.
2868 */
2869 kq->kq_state |= KQ_FLUXWAIT;
2870 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
2871 continue;
2872 }
2873 kn_enter_flux(kn);
2874 KQ_UNLOCK(kq);
2875 knote_drop(kn, td);
2876 KQ_LOCK(kq);
2877 }
2878 KQ_UNLOCK_FLUX(kq);
2879 }
2880 }
2881
2882 static int
knote_attach(struct knote * kn,struct kqueue * kq)2883 knote_attach(struct knote *kn, struct kqueue *kq)
2884 {
2885 struct klist *list;
2886
2887 KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn));
2888 KQ_OWNED(kq);
2889 MPASS(kn->kn_kq == kq);
2890
2891 if ((kq->kq_state & KQ_CLOSING) != 0)
2892 return (EBADF);
2893 if (kn->kn_fop->f_isfd) {
2894 if (kn->kn_id >= kq->kq_knlistsize)
2895 return (ENOMEM);
2896 list = &kq->kq_knlist[kn->kn_id];
2897 } else {
2898 if (kq->kq_knhash == NULL)
2899 return (ENOMEM);
2900 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2901 }
2902 SLIST_INSERT_HEAD(list, kn, kn_link);
2903 return (0);
2904 }
2905
2906 static void
knote_drop(struct knote * kn,struct thread * td)2907 knote_drop(struct knote *kn, struct thread *td)
2908 {
2909
2910 if ((kn->kn_status & KN_DETACHED) == 0)
2911 kn->kn_fop->f_detach(kn);
2912 knote_drop_detached(kn, td);
2913 }
2914
2915 static void
knote_drop_detached(struct knote * kn,struct thread * td)2916 knote_drop_detached(struct knote *kn, struct thread *td)
2917 {
2918 struct kqueue *kq;
2919 struct klist *list;
2920
2921 kq = kn->kn_kq;
2922
2923 KASSERT((kn->kn_status & KN_DETACHED) != 0,
2924 ("knote %p still attached", kn));
2925 KQ_NOTOWNED(kq);
2926
2927 KQ_LOCK(kq);
2928 for (;;) {
2929 KASSERT(kn->kn_influx >= 1,
2930 ("knote_drop called on %p with influx %d",
2931 kn, kn->kn_influx));
2932 if (kn->kn_influx == 1)
2933 break;
2934 kq->kq_state |= KQ_FLUXWAIT;
2935 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
2936 }
2937
2938 MPASS(kn->kn_kq == kq);
2939 if (kn->kn_fop->f_isfd)
2940 list = &kq->kq_knlist[kn->kn_id];
2941 else
2942 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
2943
2944 if (!SLIST_EMPTY(list))
2945 SLIST_REMOVE(list, kn, knote, kn_link);
2946 if (kn->kn_status & KN_QUEUED)
2947 knote_dequeue(kn);
2948 KQ_UNLOCK_FLUX(kq);
2949
2950 if (kn->kn_fop->f_isfd) {
2951 fdrop(kn->kn_fp, td);
2952 kn->kn_fp = NULL;
2953 }
2954 kqueue_fo_release(kn->kn_kevent.filter);
2955 kn->kn_fop = NULL;
2956 knote_free(kn);
2957 }
2958
2959 static void
knote_enqueue(struct knote * kn)2960 knote_enqueue(struct knote *kn)
2961 {
2962 struct kqueue *kq = kn->kn_kq;
2963
2964 KQ_OWNED(kn->kn_kq);
2965 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
2966
2967 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
2968 kn->kn_status |= KN_QUEUED;
2969 kq->kq_count++;
2970 kqueue_wakeup(kq);
2971 }
2972
2973 static void
knote_dequeue(struct knote * kn)2974 knote_dequeue(struct knote *kn)
2975 {
2976 struct kqueue *kq = kn->kn_kq;
2977
2978 KQ_OWNED(kn->kn_kq);
2979 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
2980
2981 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
2982 kn->kn_status &= ~KN_QUEUED;
2983 kq->kq_count--;
2984 }
2985
2986 static void
knote_init(void * dummy __unused)2987 knote_init(void *dummy __unused)
2988 {
2989
2990 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
2991 NULL, NULL, UMA_ALIGN_PTR, 0);
2992 ast_register(TDA_KQUEUE, ASTR_ASTF_REQUIRED, 0, ast_kqueue);
2993 prison0.pr_klist = knlist_alloc(&prison0.pr_mtx);
2994 }
2995 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
2996
2997 static struct knote *
knote_alloc(int mflag)2998 knote_alloc(int mflag)
2999 {
3000
3001 return (uma_zalloc(knote_zone, mflag | M_ZERO));
3002 }
3003
3004 static void
knote_free(struct knote * kn)3005 knote_free(struct knote *kn)
3006 {
3007
3008 uma_zfree(knote_zone, kn);
3009 }
3010
3011 /*
3012 * Register the kev w/ the kq specified by fd.
3013 */
3014 int
kqfd_register(int fd,struct kevent * kev,struct thread * td,int mflag)3015 kqfd_register(int fd, struct kevent *kev, struct thread *td, int mflag)
3016 {
3017 struct kqueue *kq;
3018 struct file *fp;
3019 cap_rights_t rights;
3020 int error;
3021
3022 error = fget(td, fd, cap_rights_init_one(&rights, CAP_KQUEUE_CHANGE),
3023 &fp);
3024 if (error != 0)
3025 return (error);
3026 if ((error = kqueue_acquire(fp, &kq)) != 0)
3027 goto noacquire;
3028
3029 error = kqueue_register(kq, kev, td, mflag);
3030 kqueue_release(kq, 0);
3031
3032 noacquire:
3033 fdrop(fp, td);
3034 return (error);
3035 }
3036
3037 static int
kqueue_fork_alloc(struct filedesc * fdp,struct file * fp,struct file ** fp1,struct thread * td)3038 kqueue_fork_alloc(struct filedesc *fdp, struct file *fp, struct file **fp1,
3039 struct thread *td)
3040 {
3041 struct kqueue *kq, *kq1;
3042 int error;
3043
3044 MPASS(fp->f_type == DTYPE_KQUEUE);
3045 kq = fp->f_data;
3046 if ((kq->kq_state & KQ_CPONFORK) == 0)
3047 return (EOPNOTSUPP);
3048 error = kqueue_acquire_ref(kq);
3049 if (error != 0)
3050 return (error);
3051 error = kern_kqueue_alloc(td, fdp, NULL, fp1, 0, NULL, true, &kq1);
3052 if (error == 0) {
3053 kq1->kq_forksrc = kq;
3054 (*fp1)->f_flag = fp->f_flag & (FREAD | FWRITE | FEXEC |
3055 O_CLOEXEC | O_CLOFORK);
3056 } else {
3057 kqueue_release(kq, 0);
3058 }
3059 return (error);
3060 }
3061
3062 static void
kqueue_fork_copy_knote(struct kqueue * kq1,struct knote * kn,struct proc * p1,struct filedesc * fdp)3063 kqueue_fork_copy_knote(struct kqueue *kq1, struct knote *kn, struct proc *p1,
3064 struct filedesc *fdp)
3065 {
3066 struct knote *kn1;
3067 const struct filterops *fop;
3068 int error;
3069
3070 fop = kn->kn_fop;
3071 if (fop->f_copy == NULL || (fop->f_isfd &&
3072 fdp->fd_files->fdt_ofiles[kn->kn_kevent.ident].fde_file == NULL))
3073 return;
3074 error = kqueue_expand(kq1, fop, kn->kn_kevent.ident, M_WAITOK);
3075 if (error != 0)
3076 return;
3077
3078 kn1 = knote_alloc(M_WAITOK);
3079 *kn1 = *kn;
3080 kn1->kn_status |= KN_DETACHED;
3081 kn1->kn_status &= ~KN_QUEUED;
3082 kn1->kn_kq = kq1;
3083 kn1->kn_knlist = NULL;
3084 error = fop->f_copy(kn1, p1);
3085 if (error != 0) {
3086 knote_free(kn1);
3087 return;
3088 }
3089 (void)kqueue_fo_find(kn->kn_kevent.filter);
3090 if (fop->f_isfd && !fhold(kn1->kn_fp)) {
3091 fop->f_detach(kn1);
3092 kqueue_fo_release(kn->kn_kevent.filter);
3093 knote_free(kn1);
3094 return;
3095 }
3096 if (kn->kn_knlist != NULL)
3097 knlist_add(kn->kn_knlist, kn1, 0);
3098 KQ_LOCK(kq1);
3099 knote_attach(kn1, kq1);
3100 kn1->kn_influx = 0;
3101 if ((kn->kn_status & KN_QUEUED) != 0)
3102 knote_enqueue(kn1);
3103 KQ_UNLOCK(kq1);
3104 }
3105
3106 static void
kqueue_fork_copy_list(struct klist * knlist,struct knote * marker,struct kqueue * kq,struct kqueue * kq1,struct proc * p1,struct filedesc * fdp)3107 kqueue_fork_copy_list(struct klist *knlist, struct knote *marker,
3108 struct kqueue *kq, struct kqueue *kq1, struct proc *p1,
3109 struct filedesc *fdp)
3110 {
3111 struct knote *kn;
3112
3113 KQ_OWNED(kq);
3114 kn = SLIST_FIRST(knlist);
3115 while (kn != NULL) {
3116 MPASS(kn->kn_kq == kq);
3117 if ((kn->kn_status & KN_DETACHED) != 0 ||
3118 (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0)) {
3119 kn = SLIST_NEXT(kn, kn_link);
3120 continue;
3121 }
3122 kn_enter_flux(kn);
3123 SLIST_INSERT_AFTER(kn, marker, kn_link);
3124 KQ_UNLOCK(kq);
3125 kqueue_fork_copy_knote(kq1, kn, p1, fdp);
3126 KQ_LOCK(kq);
3127 kn_leave_flux(kn);
3128 kn = SLIST_NEXT(marker, kn_link);
3129 /* XXXKIB switch kn_link to LIST? */
3130 SLIST_REMOVE(knlist, marker, knote, kn_link);
3131 }
3132 }
3133
3134 static int
kqueue_fork_copy(struct filedesc * fdp,struct file * fp,struct file * fp1,struct proc * p1,struct thread * td)3135 kqueue_fork_copy(struct filedesc *fdp, struct file *fp, struct file *fp1,
3136 struct proc *p1, struct thread *td)
3137 {
3138 struct kqueue *kq, *kq1;
3139 struct knote *marker;
3140 int error, i;
3141
3142 error = 0;
3143 MPASS(fp == NULL);
3144 MPASS(fp1->f_type == DTYPE_KQUEUE);
3145
3146 kq1 = fp1->f_data;
3147 kq = kq1->kq_forksrc;
3148 marker = knote_alloc(M_WAITOK);
3149 marker->kn_status = KN_MARKER;
3150 marker->kn_kq = kq;
3151
3152 KQ_LOCK(kq);
3153 for (i = 0; i < kq->kq_knlistsize; i++) {
3154 kqueue_fork_copy_list(&kq->kq_knlist[i], marker, kq, kq1,
3155 p1, fdp);
3156 }
3157 if (kq->kq_knhashmask != 0) {
3158 for (i = 0; i <= kq->kq_knhashmask; i++) {
3159 kqueue_fork_copy_list(&kq->kq_knhash[i], marker, kq,
3160 kq1, p1, fdp);
3161 }
3162 }
3163 kqueue_release(kq, 1);
3164 kq1->kq_forksrc = NULL;
3165 KQ_UNLOCK_FLUX(kq);
3166
3167 knote_free(marker);
3168 return (error);
3169 }
3170
3171 static int
kqueue_fork(struct filedesc * fdp,struct file * fp,struct file ** fp1,struct proc * p1,struct thread * td)3172 kqueue_fork(struct filedesc *fdp, struct file *fp, struct file **fp1,
3173 struct proc *p1, struct thread *td)
3174 {
3175 if (*fp1 == NULL)
3176 return (kqueue_fork_alloc(fdp, fp, fp1, td));
3177 return (kqueue_fork_copy(fdp, fp, *fp1, p1, td));
3178 }
3179
3180 int
knote_triv_copy(struct knote * kn __unused,struct proc * p1 __unused)3181 knote_triv_copy(struct knote *kn __unused, struct proc *p1 __unused)
3182 {
3183 return (0);
3184 }
3185
3186 struct knote_status_export_bit {
3187 int kn_status_bit;
3188 int knt_status_bit;
3189 };
3190
3191 #define ST(name) \
3192 { .kn_status_bit = KN_##name, .knt_status_bit = KNOTE_STATUS_##name }
3193 static const struct knote_status_export_bit knote_status_export_bits[] = {
3194 ST(ACTIVE),
3195 ST(QUEUED),
3196 ST(DISABLED),
3197 ST(DETACHED),
3198 ST(KQUEUE),
3199 };
3200 #undef ST
3201
3202 static int
knote_status_export(int kn_status)3203 knote_status_export(int kn_status)
3204 {
3205 const struct knote_status_export_bit *b;
3206 unsigned i;
3207 int res;
3208
3209 res = 0;
3210 for (i = 0; i < nitems(knote_status_export_bits); i++) {
3211 b = &knote_status_export_bits[i];
3212 if ((kn_status & b->kn_status_bit) != 0)
3213 res |= b->knt_status_bit;
3214 }
3215 return (res);
3216 }
3217
3218 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)3219 kern_proc_kqueue_report_one(struct sbuf *s, struct proc *p,
3220 int kq_fd, struct kqueue *kq, struct knote *kn, bool compat32 __unused)
3221 {
3222 struct kinfo_knote kin;
3223 #ifdef COMPAT_FREEBSD32
3224 struct kinfo_knote32 kin32;
3225 #endif
3226 int error;
3227
3228 if (kn->kn_status == KN_MARKER)
3229 return (0);
3230
3231 memset(&kin, 0, sizeof(kin));
3232 kin.knt_kq_fd = kq_fd;
3233 memcpy(&kin.knt_event, &kn->kn_kevent, sizeof(struct kevent));
3234 kin.knt_status = knote_status_export(kn->kn_status);
3235 kn_enter_flux(kn);
3236 KQ_UNLOCK_FLUX(kq);
3237 if (kn->kn_fop->f_userdump != NULL)
3238 (void)kn->kn_fop->f_userdump(p, kn, &kin);
3239 #ifdef COMPAT_FREEBSD32
3240 if (compat32) {
3241 freebsd32_kinfo_knote_to_32(&kin, &kin32);
3242 error = sbuf_bcat(s, &kin32, sizeof(kin32));
3243 } else
3244 #endif
3245 error = sbuf_bcat(s, &kin, sizeof(kin));
3246 KQ_LOCK(kq);
3247 kn_leave_flux(kn);
3248 return (error);
3249 }
3250
3251 static int
kern_proc_kqueue_report(struct sbuf * s,struct proc * p,int kq_fd,struct kqueue * kq,bool compat32)3252 kern_proc_kqueue_report(struct sbuf *s, struct proc *p, int kq_fd,
3253 struct kqueue *kq, bool compat32)
3254 {
3255 struct knote *kn;
3256 int error, i;
3257
3258 error = 0;
3259 KQ_LOCK(kq);
3260 for (i = 0; i < kq->kq_knlistsize; i++) {
3261 SLIST_FOREACH(kn, &kq->kq_knlist[i], kn_link) {
3262 MPASS(kn->kn_kq == kq);
3263 error = kern_proc_kqueue_report_one(s, p, kq_fd,
3264 kq, kn, compat32);
3265 if (error != 0)
3266 goto out;
3267 }
3268 }
3269 if (kq->kq_knhashmask == 0)
3270 goto out;
3271 for (i = 0; i <= kq->kq_knhashmask; i++) {
3272 SLIST_FOREACH(kn, &kq->kq_knhash[i], kn_link) {
3273 MPASS(kn->kn_kq == kq);
3274 error = kern_proc_kqueue_report_one(s, p, kq_fd,
3275 kq, kn, compat32);
3276 if (error != 0)
3277 goto out;
3278 }
3279 }
3280 out:
3281 KQ_UNLOCK_FLUX(kq);
3282 return (error);
3283 }
3284
3285 struct kern_proc_kqueues_out1_cb_args {
3286 struct sbuf *s;
3287 bool compat32;
3288 };
3289
3290 static int
kern_proc_kqueues_out1_cb(struct proc * p,int fd,struct file * fp,void * arg)3291 kern_proc_kqueues_out1_cb(struct proc *p, int fd, struct file *fp, void *arg)
3292 {
3293 struct kqueue *kq;
3294 struct kern_proc_kqueues_out1_cb_args *a;
3295
3296 if (fp->f_type != DTYPE_KQUEUE)
3297 return (0);
3298 a = arg;
3299 kq = fp->f_data;
3300 return (kern_proc_kqueue_report(a->s, p, fd, kq, a->compat32));
3301 }
3302
3303 static int
kern_proc_kqueues_out1(struct thread * td,struct proc * p,struct sbuf * s,bool compat32)3304 kern_proc_kqueues_out1(struct thread *td, struct proc *p, struct sbuf *s,
3305 bool compat32)
3306 {
3307 struct kern_proc_kqueues_out1_cb_args a;
3308
3309 a.s = s;
3310 a.compat32 = compat32;
3311 return (fget_remote_foreach(td, p, kern_proc_kqueues_out1_cb, &a));
3312 }
3313
3314 int
kern_proc_kqueues_out(struct proc * p,struct sbuf * sb,size_t maxlen,bool compat32)3315 kern_proc_kqueues_out(struct proc *p, struct sbuf *sb, size_t maxlen,
3316 bool compat32)
3317 {
3318 struct sbuf *s, sm;
3319 size_t sb_len;
3320 int error;
3321
3322 if (maxlen == -1 || maxlen == 0)
3323 sb_len = 128;
3324 else
3325 sb_len = maxlen;
3326 s = sbuf_new(&sm, NULL, sb_len, maxlen == -1 ? SBUF_AUTOEXTEND :
3327 SBUF_FIXEDLEN);
3328 error = kern_proc_kqueues_out1(curthread, p, s, compat32);
3329 sbuf_finish(s);
3330 if (error == 0) {
3331 sbuf_bcat(sb, sbuf_data(s), MIN(sbuf_len(s), maxlen == -1 ?
3332 SIZE_T_MAX : maxlen));
3333 }
3334 sbuf_delete(s);
3335 return (error);
3336 }
3337
3338 static int
sysctl_kern_proc_kqueue_one(struct thread * td,struct sbuf * s,struct proc * p,int kq_fd,bool compat32)3339 sysctl_kern_proc_kqueue_one(struct thread *td, struct sbuf *s, struct proc *p,
3340 int kq_fd, bool compat32)
3341 {
3342 struct file *fp;
3343 struct kqueue *kq;
3344 int error;
3345
3346 error = fget_remote(td, p, kq_fd, &fp);
3347 if (error == 0) {
3348 if (fp->f_type != DTYPE_KQUEUE) {
3349 error = EINVAL;
3350 } else {
3351 kq = fp->f_data;
3352 error = kern_proc_kqueue_report(s, p, kq_fd, kq,
3353 compat32);
3354 }
3355 fdrop(fp, td);
3356 }
3357 return (error);
3358 }
3359
3360 static int
sysctl_kern_proc_kqueue(SYSCTL_HANDLER_ARGS)3361 sysctl_kern_proc_kqueue(SYSCTL_HANDLER_ARGS)
3362 {
3363 struct thread *td;
3364 struct proc *p;
3365 struct sbuf *s, sm;
3366 int error, error1, *name;
3367 bool compat32;
3368
3369 name = (int *)arg1;
3370 if ((u_int)arg2 > 2 || (u_int)arg2 == 0)
3371 return (EINVAL);
3372
3373 error = pget((pid_t)name[0], PGET_HOLD | PGET_CANDEBUG, &p);
3374 if (error != 0)
3375 return (error);
3376
3377 td = curthread;
3378 #ifdef COMPAT_FREEBSD32
3379 compat32 = SV_CURPROC_FLAG(SV_ILP32);
3380 #else
3381 compat32 = false;
3382 #endif
3383
3384 s = sbuf_new_for_sysctl(&sm, NULL, 0, req);
3385 if (s == NULL) {
3386 error = ENOMEM;
3387 goto out;
3388 }
3389 sbuf_clear_flags(s, SBUF_INCLUDENUL);
3390
3391 if ((u_int)arg2 == 1) {
3392 error = kern_proc_kqueues_out1(td, p, s, compat32);
3393 } else {
3394 error = sysctl_kern_proc_kqueue_one(td, s, p,
3395 name[1] /* kq_fd */, compat32);
3396 }
3397
3398 error1 = sbuf_finish(s);
3399 if (error == 0)
3400 error = error1;
3401 sbuf_delete(s);
3402
3403 out:
3404 PRELE(p);
3405 return (error);
3406 }
3407
3408 static SYSCTL_NODE(_kern_proc, KERN_PROC_KQUEUE, kq,
3409 CTLFLAG_RD | CTLFLAG_MPSAFE,
3410 sysctl_kern_proc_kqueue, "KQueue events");
3411