summaryrefslogtreecommitdiffstats
path: root/sys/compat/linux/linux_event.c
blob: b1ceadfde50ebd92b53a1e1dc13b9e27644ada6f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
/*-
 * Copyright (c) 2007 Roman Divacky
 * Copyright (c) 2014 Dmitry Chagin
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "opt_compat.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/imgact.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/capability.h>
#include <sys/types.h>
#include <sys/user.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/errno.h>
#include <sys/event.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/selinfo.h>
#include <sys/sx.h>
#include <sys/syscallsubr.h>
#include <sys/timespec.h>

#ifdef COMPAT_LINUX32
#include <machine/../linux32/linux.h>
#include <machine/../linux32/linux32_proto.h>
#else
#include <machine/../linux/linux.h>
#include <machine/../linux/linux_proto.h>
#endif

#include <compat/linux/linux_emul.h>
#include <compat/linux/linux_event.h>
#include <compat/linux/linux_file.h>
#include <compat/linux/linux_util.h>

/*
 * epoll defines 'struct epoll_event' with the field 'data' as 64 bits
 * on all architectures. But on 32 bit architectures BSD 'struct kevent' only
 * has 32 bit opaque pointer as 'udata' field. So we can't pass epoll supplied
 * data verbatuim. Therefore we allocate 64-bit memory block to pass
 * user supplied data for every file descriptor.
 */

typedef uint64_t	epoll_udata_t;

struct epoll_emuldata {
	uint32_t	fdc;		/* epoll udata max index */
	epoll_udata_t	udata[1];	/* epoll user data vector */
};

#define	EPOLL_DEF_SZ		16
#define	EPOLL_SIZE(fdn)			\
	(sizeof(struct epoll_emuldata)+(fdn) * sizeof(epoll_udata_t))

struct epoll_event {
	uint32_t	events;
	epoll_udata_t	data;
}
#if defined(__amd64__)
__attribute__((packed))
#endif
;

#define	LINUX_MAX_EVENTS	(INT_MAX / sizeof(struct epoll_event))

static void	epoll_fd_install(struct thread *td, int fd, epoll_udata_t udata);
static int	epoll_to_kevent(struct thread *td, struct file *epfp,
		    int fd, struct epoll_event *l_event, int *kev_flags,
		    struct kevent *kevent, int *nkevents);
static void	kevent_to_epoll(struct kevent *kevent, struct epoll_event *l_event);
static int	epoll_kev_copyout(void *arg, struct kevent *kevp, int count);
static int	epoll_kev_copyin(void *arg, struct kevent *kevp, int count);
static int	epoll_delete_event(struct thread *td, struct file *epfp,
		    int fd, int filter);
static int	epoll_delete_all_events(struct thread *td, struct file *epfp,
		    int fd);

struct epoll_copyin_args {
	struct kevent	*changelist;
};

struct epoll_copyout_args {
	struct epoll_event	*leventlist;
	struct proc		*p;
	uint32_t		count;
	int			error;
};

/* eventfd */
typedef uint64_t	eventfd_t;

static fo_rdwr_t	eventfd_read;
static fo_rdwr_t	eventfd_write;
static fo_truncate_t	eventfd_truncate;
static fo_ioctl_t	eventfd_ioctl;
static fo_poll_t	eventfd_poll;
static fo_kqfilter_t	eventfd_kqfilter;
static fo_stat_t	eventfd_stat;
static fo_close_t	eventfd_close;
static fo_fill_kinfo_t	eventfd_fill_kinfo;

static struct fileops eventfdops = {
	.fo_read = eventfd_read,
	.fo_write = eventfd_write,
	.fo_truncate = eventfd_truncate,
	.fo_ioctl = eventfd_ioctl,
	.fo_poll = eventfd_poll,
	.fo_kqfilter = eventfd_kqfilter,
	.fo_stat = eventfd_stat,
	.fo_close = eventfd_close,
	.fo_chmod = invfo_chmod,
	.fo_chown = invfo_chown,
	.fo_sendfile = invfo_sendfile,
	.fo_fill_kinfo = eventfd_fill_kinfo,
	.fo_flags = DFLAG_PASSABLE
};

static void	filt_eventfddetach(struct knote *kn);
static int	filt_eventfdread(struct knote *kn, long hint);
static int	filt_eventfdwrite(struct knote *kn, long hint);

static struct filterops eventfd_rfiltops = {
	.f_isfd = 1,
	.f_detach = filt_eventfddetach,
	.f_event = filt_eventfdread
};
static struct filterops eventfd_wfiltops = {
	.f_isfd = 1,
	.f_detach = filt_eventfddetach,
	.f_event = filt_eventfdwrite
};

struct eventfd {
	eventfd_t	efd_count;
	uint32_t	efd_flags;
	struct selinfo	efd_sel;
	struct mtx	efd_lock;
};

static int	eventfd_create(struct thread *td, uint32_t initval, int flags);


static void
epoll_fd_install(struct thread *td, int fd, epoll_udata_t udata)
{
	struct linux_pemuldata *pem;
	struct epoll_emuldata *emd;
	struct proc *p;

	p = td->td_proc;

	pem = pem_find(p);
	KASSERT(pem != NULL, ("epoll proc emuldata not found.\n"));

	LINUX_PEM_XLOCK(pem);
	if (pem->epoll == NULL) {
		emd = malloc(EPOLL_SIZE(fd), M_EPOLL, M_WAITOK);
		emd->fdc = fd;
		pem->epoll = emd;
	} else {
		emd = pem->epoll;
		if (fd > emd->fdc) {
			emd = realloc(emd, EPOLL_SIZE(fd), M_EPOLL, M_WAITOK);
			emd->fdc = fd;
			pem->epoll = emd;
		}
	}
	emd->udata[fd] = udata;
	LINUX_PEM_XUNLOCK(pem);
}

static int
epoll_create_common(struct thread *td, int flags)
{
	int error;

	error = kern_kqueue(td, flags, NULL);
	if (error)
		return (error);

	epoll_fd_install(td, EPOLL_DEF_SZ, 0);

	return (0);
}

int
linux_epoll_create(struct thread *td, struct linux_epoll_create_args *args)
{

	/*
	 * args->size is unused. Linux just tests it
	 * and then forgets it as well.
	 */
	if (args->size <= 0)
		return (EINVAL);

	return (epoll_create_common(td, 0));
}

int
linux_epoll_create1(struct thread *td, struct linux_epoll_create1_args *args)
{
	int flags;

	if ((args->flags & ~(LINUX_O_CLOEXEC)) != 0)
		return (EINVAL);

	flags = 0;
	if ((args->flags & LINUX_O_CLOEXEC) != 0)
		flags |= O_CLOEXEC;

	return (epoll_create_common(td, flags));
}

/* Structure converting function from epoll to kevent. */
static int
epoll_to_kevent(struct thread *td, struct file *epfp,
    int fd, struct epoll_event *l_event, int *kev_flags,
    struct kevent *kevent, int *nkevents)
{
	uint32_t levents = l_event->events;
	struct linux_pemuldata *pem;
	struct proc *p;

	/* flags related to how event is registered */
	if ((levents & LINUX_EPOLLONESHOT) != 0)
		*kev_flags |= EV_ONESHOT;
	if ((levents & LINUX_EPOLLET) != 0)
		*kev_flags |= EV_CLEAR;
	if ((levents & LINUX_EPOLLERR) != 0)
		*kev_flags |= EV_ERROR;
	if ((levents & LINUX_EPOLLRDHUP) != 0)
		*kev_flags |= EV_EOF;

	/* flags related to what event is registered */
	if ((levents & LINUX_EPOLL_EVRD) != 0) {
		EV_SET(kevent++, fd, EVFILT_READ, *kev_flags, 0, 0, 0);
		++(*nkevents);
	}
	if ((levents & LINUX_EPOLL_EVWR) != 0) {
		EV_SET(kevent++, fd, EVFILT_WRITE, *kev_flags, 0, 0, 0);
		++(*nkevents);
	}

	if ((levents & ~(LINUX_EPOLL_EVSUP)) != 0) {
		p = td->td_proc;

		pem = pem_find(p);
		KASSERT(pem != NULL, ("epoll proc emuldata not found.\n"));
		KASSERT(pem->epoll != NULL, ("epoll proc epolldata not found.\n"));

		LINUX_PEM_XLOCK(pem);
		if ((pem->flags & LINUX_XUNSUP_EPOLL) == 0) {
			pem->flags |= LINUX_XUNSUP_EPOLL;
			LINUX_PEM_XUNLOCK(pem);
			linux_msg(td, "epoll_ctl unsupported flags: 0x%x\n",
			    levents);
		} else
			LINUX_PEM_XUNLOCK(pem);
		return (EINVAL);
	}

	return (0);
}

/* 
 * Structure converting function from kevent to epoll. In a case
 * this is called on error in registration we store the error in
 * event->data and pick it up later in linux_epoll_ctl().
 */
static void
kevent_to_epoll(struct kevent *kevent, struct epoll_event *l_event)
{

	if ((kevent->flags & EV_ERROR) != 0) {
		l_event->events = LINUX_EPOLLERR;
		return;
	}

	switch (kevent->filter) {
	case EVFILT_READ:
		l_event->events = LINUX_EPOLLIN|LINUX_EPOLLRDNORM|LINUX_EPOLLPRI;
		if ((kevent->flags & EV_EOF) != 0)
			l_event->events |= LINUX_EPOLLRDHUP;
	break;
	case EVFILT_WRITE:
		l_event->events = LINUX_EPOLLOUT|LINUX_EPOLLWRNORM;
	break;
	}
}

/* 
 * Copyout callback used by kevent. This converts kevent
 * events to epoll events and copies them back to the
 * userspace. This is also called on error on registering
 * of the filter.
 */
static int
epoll_kev_copyout(void *arg, struct kevent *kevp, int count)
{
	struct epoll_copyout_args *args;
	struct linux_pemuldata *pem;
	struct epoll_emuldata *emd;
	struct epoll_event *eep;
	int error, fd, i;

	args = (struct epoll_copyout_args*) arg;
	eep = malloc(sizeof(*eep) * count, M_EPOLL, M_WAITOK | M_ZERO);

	pem = pem_find(args->p);
	KASSERT(pem != NULL, ("epoll proc emuldata not found.\n"));
	LINUX_PEM_SLOCK(pem);
	emd = pem->epoll;
	KASSERT(emd != NULL, ("epoll proc epolldata not found.\n"));

	for (i = 0; i < count; i++) {
		kevent_to_epoll(&kevp[i], &eep[i]);

		fd = kevp[i].ident;
		KASSERT(fd <= emd->fdc, ("epoll user data vector"
						    " is too small.\n"));
		eep[i].data = emd->udata[fd];
	}
	LINUX_PEM_SUNLOCK(pem);

	error = copyout(eep, args->leventlist, count * sizeof(*eep));
	if (error == 0) {
		args->leventlist += count;
		args->count += count;
	} else if (args->error == 0)
		args->error = error;

	free(eep, M_EPOLL);
	return (error);
}

/*
 * Copyin callback used by kevent. This copies already
 * converted filters from kernel memory to the kevent 
 * internal kernel memory. Hence the memcpy instead of
 * copyin.
 */
static int
epoll_kev_copyin(void *arg, struct kevent *kevp, int count)
{
	struct epoll_copyin_args *args;

	args = (struct epoll_copyin_args*) arg;
	
	memcpy(kevp, args->changelist, count * sizeof(*kevp));
	args->changelist += count;

	return (0);
}

/*
 * Load epoll filter, convert it to kevent filter
 * and load it into kevent subsystem.
 */
int
linux_epoll_ctl(struct thread *td, struct linux_epoll_ctl_args *args)
{
	struct file *epfp, *fp;
	struct epoll_copyin_args ciargs;
	struct kevent kev[2];
	struct kevent_copyops k_ops = { &ciargs,
					NULL,
					epoll_kev_copyin};
	struct epoll_event le;
	cap_rights_t rights;
	int kev_flags;
	int nchanges = 0;
	int error;

	if (args->op != LINUX_EPOLL_CTL_DEL) {
		error = copyin(args->event, &le, sizeof(le));
		if (error != 0)
			return (error);
	}

	error = fget(td, args->epfd,
	    cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &epfp);
	if (error != 0)
		return (error);
	if (epfp->f_type != DTYPE_KQUEUE)
		goto leave1;

	 /* Protect user data vector from incorrectly supplied fd. */
	error = fget(td, args->fd, cap_rights_init(&rights, CAP_POLL_EVENT), &fp);
	if (error != 0)
		goto leave1;

	/* Linux disallows spying on himself */
	if (epfp == fp) {
		error = EINVAL;
		goto leave0;
	}

	ciargs.changelist = kev;

	switch (args->op) {
	case LINUX_EPOLL_CTL_MOD:
		/*
		 * We don't memorize which events were set for this FD
		 * on this level, so just delete all we could have set:
		 * EVFILT_READ and EVFILT_WRITE, ignoring any errors
		 */
		error = epoll_delete_all_events(td, epfp, args->fd);
		if (error)
			goto leave0;
		/* FALLTHROUGH */

	case LINUX_EPOLL_CTL_ADD:
			kev_flags = EV_ADD | EV_ENABLE;
		break;

	case LINUX_EPOLL_CTL_DEL:
		/* CTL_DEL means unregister this fd with this epoll */
		error = epoll_delete_all_events(td, epfp, args->fd);
		goto leave0;

	default:
		error = EINVAL;
		goto leave0;
	}

	error = epoll_to_kevent(td, epfp, args->fd, &le, &kev_flags,
	    kev, &nchanges);
	if (error)
		goto leave0;

	epoll_fd_install(td, args->fd, le.data);

	error = kern_kevent_fp(td, epfp, nchanges, 0, &k_ops, NULL);

leave0:
	fdrop(fp, td);

leave1:
	fdrop(epfp, td);
	return (error);
}

/*
 * Wait for a filter to be triggered on the epoll file descriptor.
 */
static int
linux_epoll_wait_common(struct thread *td, int epfd, struct epoll_event *events,
    int maxevents, int timeout, sigset_t *uset)
{
	struct file *epfp;
	struct timespec ts, *tsp;
	cap_rights_t rights;
	struct epoll_copyout_args coargs;
	struct kevent_copyops k_ops = { &coargs,
					epoll_kev_copyout,
					NULL};
	int error;

	if (maxevents <= 0 || maxevents > LINUX_MAX_EVENTS)
		return (EINVAL);

	if (uset != NULL) {
		error = kern_sigprocmask(td, SIG_SETMASK, uset,
		    &td->td_oldsigmask, 0);
		if (error != 0)
			return (error);
		td->td_pflags |= TDP_OLDMASK;
		/*
		 * Make sure that ast() is called on return to
		 * usermode and TDP_OLDMASK is cleared, restoring old
		 * sigmask.
		 */
		thread_lock(td);
		td->td_flags |= TDF_ASTPENDING;
		thread_unlock(td);
	}

	error = fget(td, epfd,
	    cap_rights_init(&rights, CAP_KQUEUE_EVENT), &epfp);
	if (error != 0)
		return (error);

	coargs.leventlist = events;
	coargs.p = td->td_proc;
	coargs.count = 0;
	coargs.error = 0;

	if (timeout != -1) {
		if (timeout < 0) {
			error = EINVAL;
			goto leave;
		}
		/* Convert from milliseconds to timespec. */
		ts.tv_sec = timeout / 1000;
		ts.tv_nsec = (timeout % 1000) * 1000000;
		tsp = &ts;
	} else {
		tsp = NULL;
	}

	error = kern_kevent_fp(td, epfp, 0, maxevents, &k_ops, tsp);
	if (error == 0 && coargs.error != 0)
		error = coargs.error;

	/* 
	 * kern_kevent might return ENOMEM which is not expected from epoll_wait.
	 * Maybe we should translate that but I don't think it matters at all.
	 */
	if (error == 0)
		td->td_retval[0] = coargs.count;
leave:
	fdrop(epfp, td);
	return (error);
}

int
linux_epoll_wait(struct thread *td, struct linux_epoll_wait_args *args)
{

	return (linux_epoll_wait_common(td, args->epfd, args->events,
	    args->maxevents, args->timeout, NULL));
}

int
linux_epoll_pwait(struct thread *td, struct linux_epoll_pwait_args *args)
{
	sigset_t mask, *pmask;
	l_sigset_t lmask;
	int error;

	if (args->mask != NULL) {
		error = copyin(args->mask, &lmask, sizeof(l_sigset_t));
		if (error != 0)
			return (error);
		linux_to_bsd_sigset(&lmask, &mask);
		pmask = &mask;
	} else
		pmask = NULL;
	return (linux_epoll_wait_common(td, args->epfd, args->events,
	    args->maxevents, args->timeout, pmask));
}

static int
epoll_delete_event(struct thread *td, struct file *epfp, int fd, int filter)
{
	struct epoll_copyin_args ciargs;
	struct kevent kev;
	struct kevent_copyops k_ops = { &ciargs,
					NULL,
					epoll_kev_copyin};
	int error;

	ciargs.changelist = &kev;
	EV_SET(&kev, fd, filter, EV_DELETE | EV_DISABLE, 0, 0, 0);

	error = kern_kevent_fp(td, epfp, 1, 0, &k_ops, NULL);

	/*
	 * here we ignore ENONT, because we don't keep track of events here
	 */
	if (error == ENOENT)
		error = 0;
	return (error);
}

static int
epoll_delete_all_events(struct thread *td, struct file *epfp, int fd)
{
	int error1, error2;

	error1 = epoll_delete_event(td, epfp, fd, EVFILT_READ);
	error2 = epoll_delete_event(td, epfp, fd, EVFILT_WRITE);

	/* report any errors we got */
	return (error1 == 0 ? error2 : error1);
}

static int
eventfd_create(struct thread *td, uint32_t initval, int flags)
{
	struct filedesc *fdp;
	struct eventfd *efd;
	struct file *fp;
	int fflags, fd, error;

	fflags = 0;
	if ((flags & LINUX_O_CLOEXEC) != 0)
		fflags |= O_CLOEXEC;

	fdp = td->td_proc->p_fd;
	error = falloc(td, &fp, &fd, fflags);
	if (error)
		return (error);

	efd = malloc(sizeof(*efd), M_EPOLL, M_WAITOK | M_ZERO);
	efd->efd_flags = flags;
	efd->efd_count = initval;
	mtx_init(&efd->efd_lock, "eventfd", NULL, MTX_DEF);

	knlist_init_mtx(&efd->efd_sel.si_note, &efd->efd_lock);

	fflags = FREAD | FWRITE; 
	if ((flags & LINUX_O_NONBLOCK) != 0)
		fflags |= FNONBLOCK;

	finit(fp, fflags, DTYPE_LINUXEFD, efd, &eventfdops);
	fdrop(fp, td);

	td->td_retval[0] = fd;
	return (error);
}

int
linux_eventfd(struct thread *td, struct linux_eventfd_args *args)
{

	return (eventfd_create(td, args->initval, 0));
}

int
linux_eventfd2(struct thread *td, struct linux_eventfd2_args *args)
{

	if ((args->flags & ~(LINUX_O_CLOEXEC|LINUX_O_NONBLOCK|LINUX_EFD_SEMAPHORE)) != 0)
		return (EINVAL);

	return (eventfd_create(td, args->initval, args->flags));
}

static int
eventfd_close(struct file *fp, struct thread *td)
{
	struct eventfd *efd;

	efd = fp->f_data;
	if (fp->f_type != DTYPE_LINUXEFD || efd == NULL)
		return (EBADF);

	seldrain(&efd->efd_sel);
	knlist_destroy(&efd->efd_sel.si_note);

	fp->f_ops = &badfileops;
	mtx_destroy(&efd->efd_lock);
	free(efd, M_EPOLL);

	return (0);
}

static int
eventfd_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
	int flags, struct thread *td)
{
	struct eventfd *efd;
	eventfd_t count;
	int error;

	efd = fp->f_data;
	if (fp->f_type != DTYPE_LINUXEFD || efd == NULL)
		return (EBADF);

	if (uio->uio_resid < sizeof(eventfd_t))
		return (EINVAL);

	error = 0;
	mtx_lock(&efd->efd_lock);
retry:
	if (efd->efd_count == 0) {
		if ((efd->efd_flags & LINUX_O_NONBLOCK) != 0) {
			mtx_unlock(&efd->efd_lock);
			return (EAGAIN);
		}
		error = mtx_sleep(&efd->efd_count, &efd->efd_lock, PCATCH, "lefdrd", 0);
		if (error == 0)
			goto retry;
	}
	if (error == 0) {
		if ((efd->efd_flags & LINUX_EFD_SEMAPHORE) != 0) {
			count = 1;
			--efd->efd_count;
		} else {
			count = efd->efd_count;
			efd->efd_count = 0;
		}
		KNOTE_LOCKED(&efd->efd_sel.si_note, 0);
		selwakeup(&efd->efd_sel);
		wakeup(&efd->efd_count);
		mtx_unlock(&efd->efd_lock);
		error = uiomove(&count, sizeof(eventfd_t), uio);
	} else
		mtx_unlock(&efd->efd_lock);

	return (error);
}

static int
eventfd_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
	 int flags, struct thread *td)
{
	struct eventfd *efd;
	eventfd_t count;
	int error;

	efd = fp->f_data;
	if (fp->f_type != DTYPE_LINUXEFD || efd == NULL)
		return (EBADF);

	if (uio->uio_resid < sizeof(eventfd_t))
		return (EINVAL);

	error = uiomove(&count, sizeof(eventfd_t), uio);
	if (error)
		return (error);
	if (count == UINT64_MAX)
		return (EINVAL);

	mtx_lock(&efd->efd_lock);
retry:
	if (UINT64_MAX - efd->efd_count <= count) {
		if ((efd->efd_flags & LINUX_O_NONBLOCK) != 0) {
			mtx_unlock(&efd->efd_lock);
			return (EAGAIN);
		}
		error = mtx_sleep(&efd->efd_count, &efd->efd_lock,
		    PCATCH, "lefdwr", 0);
		if (error == 0)
			goto retry;
	}
	if (error == 0) {
		efd->efd_count += count;
		KNOTE_LOCKED(&efd->efd_sel.si_note, 0);
		selwakeup(&efd->efd_sel);
		wakeup(&efd->efd_count);
	}
	mtx_unlock(&efd->efd_lock);

	return (error);
}

static int
eventfd_poll(struct file *fp, int events, struct ucred *active_cred,
	struct thread *td)
{
	struct eventfd *efd;
	int revents = 0;

	efd = fp->f_data;
	if (fp->f_type != DTYPE_LINUXEFD || efd == NULL)
		return (POLLERR);

	mtx_lock(&efd->efd_lock);
	if ((events & (POLLIN|POLLRDNORM)) && efd->efd_count > 0)
		revents |= events & (POLLIN|POLLRDNORM);
	if ((events & (POLLOUT|POLLWRNORM)) && UINT64_MAX - 1 > efd->efd_count)
		revents |= events & (POLLOUT|POLLWRNORM);
	if (revents == 0)
		selrecord(td, &efd->efd_sel);
	mtx_unlock(&efd->efd_lock);

	return (revents);
}

/*ARGSUSED*/
static int
eventfd_kqfilter(struct file *fp, struct knote *kn)
{
	struct eventfd *efd;

	efd = fp->f_data;
	if (fp->f_type != DTYPE_LINUXEFD || efd == NULL)
		return (EINVAL);

	mtx_lock(&efd->efd_lock);
	switch (kn->kn_filter) {
	case EVFILT_READ:
		kn->kn_fop = &eventfd_rfiltops;
		break;
	case EVFILT_WRITE:
		kn->kn_fop = &eventfd_wfiltops;
		break;
	default:
		mtx_unlock(&efd->efd_lock);
		return (EINVAL);
	}

	kn->kn_hook = efd;
	knlist_add(&efd->efd_sel.si_note, kn, 1);
	mtx_unlock(&efd->efd_lock);

	return (0);
}

static void
filt_eventfddetach(struct knote *kn)
{
	struct eventfd *efd = kn->kn_hook;

	mtx_lock(&efd->efd_lock);
	knlist_remove(&efd->efd_sel.si_note, kn, 1);
	mtx_unlock(&efd->efd_lock);
}

/*ARGSUSED*/
static int
filt_eventfdread(struct knote *kn, long hint)
{
	struct eventfd *efd = kn->kn_hook;
	int ret;

	mtx_assert(&efd->efd_lock, MA_OWNED);
	ret = (efd->efd_count > 0);

	return (ret);
}

/*ARGSUSED*/
static int
filt_eventfdwrite(struct knote *kn, long hint)
{
	struct eventfd *efd = kn->kn_hook;
	int ret;

	mtx_assert(&efd->efd_lock, MA_OWNED);
	ret = (UINT64_MAX - 1 > efd->efd_count);

	return (ret);
}

/*ARGSUSED*/
static int
eventfd_truncate(struct file *fp, off_t length, struct ucred *active_cred,
	struct thread *td)
{

	return (ENXIO);
}

/*ARGSUSED*/
static int
eventfd_ioctl(struct file *fp, u_long cmd, void *data,
	struct ucred *active_cred, struct thread *td)
{

	return (ENXIO);
}

/*ARGSUSED*/
static int
eventfd_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
	struct thread *td)
{

	return (ENXIO);
}

/*ARGSUSED*/
static int
eventfd_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
{

	kif->kf_type = KF_TYPE_UNKNOWN;
	return (0);
}
OpenPOWER on IntegriCloud