summaryrefslogtreecommitdiff
path: root/sys/kern/kern_descrip.c
blob: 571e24a494610f8ba925ac29975f9a370e58a1f1 (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
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
/*	$OpenBSD: kern_descrip.c,v 1.38 2001/10/07 23:12:06 art Exp $	*/
/*	$NetBSD: kern_descrip.c,v 1.42 1996/03/30 22:24:38 christos Exp $	*/

/*
 * Copyright (c) 1982, 1986, 1989, 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *	@(#)kern_descrip.c	8.6 (Berkeley) 4/19/94
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/syslog.h>
#include <sys/ucred.h>
#include <sys/unistd.h>
#include <sys/resourcevar.h>
#include <sys/conf.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <sys/event.h>
#include <sys/pool.h>

#include <vm/vm.h>

#include <sys/pipe.h>

/*
 * Descriptor management.
 */
struct filelist filehead;	/* head of list of open files */
int nfiles;			/* actual number of open files */

static __inline void fd_used __P((struct filedesc *, int));
static __inline void fd_unused __P((struct filedesc *, int));
static __inline int find_next_zero __P((u_int *, int, u_int));
int finishdup __P((struct filedesc *, int, int, register_t *));
int find_last_set __P((struct filedesc *, int));

struct pool file_pool;
struct pool fdesc_pool;

void
filedesc_init()
{
	pool_init(&file_pool, sizeof(struct file), 0, 0, 0, "filepl",
		0, pool_page_alloc_nointr, pool_page_free_nointr, M_PROC);
	pool_init(&fdesc_pool, sizeof(struct filedesc0), 0, 0, 0, "fdescpl",
		0, pool_page_alloc_nointr, pool_page_free_nointr, M_FILEDESC);
}

static __inline int
find_next_zero (u_int *bitmap, int want, u_int bits)
{
	int i, off, maxoff;
	u_int sub;

	if (want > bits)
		return -1;

	off = want >> NDENTRYSHIFT;
	i = want & NDENTRYMASK;
	if (i) {
		sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i));
		if (sub != ~0)
			goto found;
		off++;
	}

	maxoff = NDLOSLOTS(bits);
	while (off < maxoff) {
		if ((sub = bitmap[off]) != ~0)
			goto found;
		off++;
	}

	return -1;

 found:
	return (off << NDENTRYSHIFT) + ffs(~sub) - 1;
}

int
find_last_set(struct filedesc *fd, int last)
{
	int off, i;
	struct file **ofiles = fd->fd_ofiles;
	u_int *bitmap = fd->fd_lomap;

	off = (last - 1) >> NDENTRYSHIFT;

	while (!bitmap[off] && off >= 0)
		off--;
	if (off < 0)
		return 0;

	i = ((off + 1) << NDENTRYSHIFT) - 1;
	if (i >= last)
		i = last - 1;

	while (i > 0 && ofiles[i] == NULL)
		i--;
	return i;
}

static __inline void
fd_used(fdp, fd)
	register struct filedesc *fdp;
	register int fd;
{
	u_int off = fd >> NDENTRYSHIFT;

	fdp->fd_lomap[off] |= 1 << (fd & NDENTRYMASK);
	if (fdp->fd_lomap[off] == ~0)
		fdp->fd_himap[off >> NDENTRYSHIFT] |= 1 << (off & NDENTRYMASK);

	if (fd > fdp->fd_lastfile)
		fdp->fd_lastfile = fd;
}

static __inline void
fd_unused(fdp, fd)
	register struct filedesc *fdp;
	register int fd;
{
	u_int off = fd >> NDENTRYSHIFT;

	if (fd < fdp->fd_freefile)
		fdp->fd_freefile = fd;

	if (fdp->fd_lomap[off] == ~0)
		fdp->fd_himap[off >> NDENTRYSHIFT] &= ~(1 << (off & NDENTRYMASK));
	fdp->fd_lomap[off] &= ~(1 << (fd & NDENTRYMASK));

#ifdef DIAGNOSTIC
	if (fd > fdp->fd_lastfile)
		panic("fd_unused: fd_lastfile inconsistent");
#endif
	if (fd == fdp->fd_lastfile)
		fdp->fd_lastfile = find_last_set(fdp, fd);
}

/*
 * System calls on descriptors.
 */

/*
 * Duplicate a file descriptor.
 */
/* ARGSUSED */
int
sys_dup(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_dup_args /* {
		syscallarg(u_int) fd;
	} */ *uap = v;
	register struct filedesc *fdp = p->p_fd;
	register int old = SCARG(uap, fd);
	int new;
	int error;

	if ((u_int)old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL)
		return (EBADF);
	if ((error = fdalloc(p, 0, &new)) != 0)
		return (error);
	return (finishdup(fdp, old, new, retval));
}

/*
 * Duplicate a file descriptor to a particular value.
 */
/* ARGSUSED */
int
sys_dup2(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_dup2_args /* {
		syscallarg(u_int) from;
		syscallarg(u_int) to;
	} */ *uap = v;
	struct filedesc *fdp = p->p_fd;
	int old = SCARG(uap, from), new = SCARG(uap, to);
	int i, error;

	if ((u_int)old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL ||
	    (u_int)new >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
	    (u_int)new >= maxfiles)
		return (EBADF);
	if (old == new) {
		*retval = new;
		return (0);
	}
	if (new >= fdp->fd_nfiles) {
		if ((error = fdalloc(p, new, &i)) != 0)
			return (error);
		if (new != i)
			panic("dup2: fdalloc");
	} else {
		(void) fdrelease(p, new);
	}
	return (finishdup(fdp, old, new, retval));
}

/*
 * The file control system call.
 */
/* ARGSUSED */
int
sys_fcntl(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_fcntl_args /* {
		syscallarg(int) fd;
		syscallarg(int) cmd;
		syscallarg(void *) arg;
	} */ *uap = v;
	int fd = SCARG(uap, fd);
	struct filedesc *fdp = p->p_fd;
	struct file *fp;
	struct vnode *vp;
	int i, tmp, error, flg = F_POSIX;
	struct flock fl;
	int newmin;

	if ((u_int)fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[fd]) == NULL)
		return (EBADF);
	switch (SCARG(uap, cmd)) {

	case F_DUPFD:
		newmin = (long)SCARG(uap, arg);
		if ((u_int)newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
		    (u_int)newmin >= maxfiles)
			return (EINVAL);
		if ((error = fdalloc(p, newmin, &i)) != 0)
			return (error);
		return (finishdup(fdp, fd, i, retval));

	case F_GETFD:
		*retval = fdp->fd_ofileflags[fd] & UF_EXCLOSE ? 1 : 0;
		return (0);

	case F_SETFD:
		if ((long)SCARG(uap, arg) & 1)
			fdp->fd_ofileflags[fd] |= UF_EXCLOSE;
		else
			fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE;
		return (0);

	case F_GETFL:
		*retval = OFLAGS(fp->f_flag);
		return (0);

	case F_SETFL:
		fp->f_flag &= ~FCNTLFLAGS;
		fp->f_flag |= FFLAGS((long)SCARG(uap, arg)) & FCNTLFLAGS;
		tmp = fp->f_flag & FNONBLOCK;
		error = (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
		if (error)
			return (error);
		tmp = fp->f_flag & FASYNC;
		error = (*fp->f_ops->fo_ioctl)(fp, FIOASYNC, (caddr_t)&tmp, p);
		if (!error)
			return (0);
		fp->f_flag &= ~FNONBLOCK;
		tmp = 0;
		(void) (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
		return (error);

	case F_GETOWN:
		if (fp->f_type == DTYPE_SOCKET) {
			*retval = ((struct socket *)fp->f_data)->so_pgid;
			return (0);
		}
		error = (*fp->f_ops->fo_ioctl)
			(fp, TIOCGPGRP, (caddr_t)retval, p);
		*retval = -*retval;
		return (error);

	case F_SETOWN:
		if (fp->f_type == DTYPE_SOCKET) {
			struct socket *so = (struct socket *)fp->f_data;

			so->so_pgid = (long)SCARG(uap, arg);
			so->so_siguid = p->p_cred->p_ruid;
			so->so_sigeuid = p->p_ucred->cr_uid;
			return (0);
		}
		if ((long)SCARG(uap, arg) <= 0) {
			SCARG(uap, arg) = (void *)(-(long)SCARG(uap, arg));
		} else {
			struct proc *p1 = pfind((long)SCARG(uap, arg));
			if (p1 == 0)
				return (ESRCH);
			SCARG(uap, arg) = (void *)(long)p1->p_pgrp->pg_id;
		}
		return ((*fp->f_ops->fo_ioctl)
			(fp, TIOCSPGRP, (caddr_t)&SCARG(uap, arg), p));

	case F_SETLKW:
		flg |= F_WAIT;
		/* FALLTHROUGH */

	case F_SETLK:
		if (fp->f_type != DTYPE_VNODE)
			return (EBADF);
		vp = (struct vnode *)fp->f_data;
		/* Copy in the lock structure */
		error = copyin((caddr_t)SCARG(uap, arg), (caddr_t)&fl,
		    sizeof (fl));
		if (error)
			return (error);
		if (fl.l_whence == SEEK_CUR) {
			if (fl.l_start == 0 && fl.l_len < 0) {
				/* lockf(3) compliance hack */
				fl.l_len = -fl.l_len;
				fl.l_start = fp->f_offset - fl.l_len;
			} else
				fl.l_start += fp->f_offset;
		}
		switch (fl.l_type) {

		case F_RDLCK:
			if ((fp->f_flag & FREAD) == 0)
				return (EBADF);
			p->p_flag |= P_ADVLOCK;
			return (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &fl, flg));

		case F_WRLCK:
			if ((fp->f_flag & FWRITE) == 0)
				return (EBADF);
			p->p_flag |= P_ADVLOCK;
			return (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &fl, flg));

		case F_UNLCK:
			return (VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &fl,
				F_POSIX));

		default:
			return (EINVAL);
		}

	case F_GETLK:
		if (fp->f_type != DTYPE_VNODE)
			return (EBADF);
		vp = (struct vnode *)fp->f_data;
		/* Copy in the lock structure */
		error = copyin((caddr_t)SCARG(uap, arg), (caddr_t)&fl,
		    sizeof (fl));
		if (error)
			return (error);
		if (fl.l_whence == SEEK_CUR) {
			if (fl.l_start == 0 && fl.l_len < 0) {
				/* lockf(3) compliance hack */
				fl.l_len = -fl.l_len;
				fl.l_start = fp->f_offset - fl.l_len;
			} else
				fl.l_start += fp->f_offset;
		}
		if (fl.l_type != F_RDLCK &&
		    fl.l_type != F_WRLCK &&
		    fl.l_type != F_UNLCK &&
		    fl.l_type != 0)
			return (EINVAL);
		error = VOP_ADVLOCK(vp, (caddr_t)p, F_GETLK, &fl, F_POSIX);
		if (error)
			return (error);
		return (copyout((caddr_t)&fl, (caddr_t)SCARG(uap, arg),
		    sizeof (fl)));

	default:
		return (EINVAL);
	}
	/* NOTREACHED */
}

/*
 * Common code for dup, dup2, and fcntl(F_DUPFD).
 */
int
finishdup(fdp, old, new, retval)
	register struct filedesc *fdp;
	register int old, new;
	register_t *retval;
{
	register struct file *fp;

	fp = fdp->fd_ofiles[old];
	if (fp->f_count == LONG_MAX-2)
		return (EDEADLK);
	fdp->fd_ofiles[new] = fp;
	fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE;
	fp->f_count++;
	fd_used(fdp, new);
	*retval = new;
	return (0);
}

void
fdremove(fdp, fd)
	struct filedesc *fdp;
	int fd;
{
	fdp->fd_ofiles[fd] = NULL;
	fd_unused(fdp, fd);
}

int
fdrelease(p, fd)
	struct proc *p;
	int fd;
{
	struct filedesc *fdp = p->p_fd;
	struct file **fpp, *fp;

	fpp = &fdp->fd_ofiles[fd];
	fp = *fpp;
	if (fp == NULL)
		return (EBADF);
	*fpp = NULL;
	fdp->fd_ofileflags[fd] = 0;
	fd_unused(fdp, fd);
	if (fd < fdp->fd_knlistsize)
		knote_fdclose(p, fd);
	return (closef(fp, p));
}

/*
 * Close a file descriptor.
 */
/* ARGSUSED */
int
sys_close(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_close_args /* {
		syscallarg(int) fd;
	} */ *uap = v;
	int fd = SCARG(uap, fd);
	register struct filedesc *fdp = p->p_fd;

	if ((u_int)fd >= fdp->fd_nfiles)
		return (EBADF);
	return (fdrelease(p, fd));
}

/*
 * Return status information about a file descriptor.
 */
/* ARGSUSED */
int
sys_fstat(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_fstat_args /* {
		syscallarg(int) fd;
		syscallarg(struct stat *) sb;
	} */ *uap = v;
	int fd = SCARG(uap, fd);
	struct filedesc *fdp = p->p_fd;
	struct file *fp;
	struct stat ub;
	int error;

	if ((u_int)fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[fd]) == NULL)
		return (EBADF);
	error = (*fp->f_ops->fo_stat)(fp, &ub, p);
	if (error == 0) {
		/* Don't let non-root see generation numbers
		   (for NFS security) */
		if (suser(p->p_ucred, &p->p_acflag))
			ub.st_gen = 0;
		error = copyout((caddr_t)&ub, (caddr_t)SCARG(uap, sb),
		    sizeof (ub));
	}
	return (error);
}

/*
 * Return pathconf information about a file descriptor.
 */
/* ARGSUSED */
int
sys_fpathconf(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_fpathconf_args /* {
		syscallarg(int) fd;
		syscallarg(int) name;
	} */ *uap = v;
	int fd = SCARG(uap, fd);
	struct filedesc *fdp = p->p_fd;
	struct file *fp;
	struct vnode *vp;

	if ((u_int)fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[fd]) == NULL)
		return (EBADF);
	switch (fp->f_type) {
	case DTYPE_PIPE:
	case DTYPE_SOCKET:
		if (SCARG(uap, name) != _PC_PIPE_BUF)
			return (EINVAL);
		*retval = PIPE_BUF;
		return (0);

	case DTYPE_VNODE:
		vp = (struct vnode *)fp->f_data;
		return (VOP_PATHCONF(vp, SCARG(uap, name), retval));

	default:
		return (EOPNOTSUPP);
	}
	/*NOTREACHED*/
}

/*
 * Allocate a file descriptor for the process.
 */
int fdexpand;

int
fdalloc(p, want, result)
	struct proc *p;
	int want;
	int *result;
{
	register struct filedesc *fdp = p->p_fd;
	register int i;
	int lim, last, nfiles;
	struct file **newofile;
	char *newofileflags;
	u_int *newhimap, *newlomap, new, off;

	/*
	 * Search for a free descriptor starting at the higher
	 * of want or fd_freefile.  If that fails, consider
	 * expanding the ofile array.
	 */
	lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
	for (;;) {
		last = min(fdp->fd_nfiles, lim);
		if ((i = want) < fdp->fd_freefile)
			i = fdp->fd_freefile;
		off = i >> NDENTRYSHIFT;
		new = find_next_zero(fdp->fd_himap, off,
		    (last + NDENTRIES - 1) >> NDENTRYSHIFT);
		if (new != -1) {
			i = find_next_zero(&fdp->fd_lomap[new], 
					   new > off ? 0 : i & NDENTRYMASK,
					   NDENTRIES);
			if (i == -1) {
				/* free file descriptor in this block was
				 * below want, try again with higher want.
				 */
				want = (new + 1) << NDENTRYSHIFT;
				continue;
			}
			i += (new << NDENTRYSHIFT);
			if (i < last) {
				fd_used(fdp, i);
				if (want <= fdp->fd_freefile)
					fdp->fd_freefile = i;
				*result = i;
				return (0);
			}
		}

		/*
		 * No space in current array.  Expand?
		 */
		if (fdp->fd_nfiles >= lim)
			return (EMFILE);
		if (fdp->fd_nfiles < NDEXTENT)
			nfiles = NDEXTENT;
		else
			nfiles = 2 * fdp->fd_nfiles;
		nfiles = min(lim, nfiles);
		newofile = malloc(nfiles * OFILESIZE, M_FILEDESC, M_WAITOK);
		newofileflags = (char *) &newofile[nfiles];

		/*
		 * Copy the existing ofile and ofileflags arrays
		 * and zero the new portion of each array.
		 */
		bcopy(fdp->fd_ofiles, newofile,
			(i = sizeof(struct file *) * fdp->fd_nfiles));
		bzero((char *)newofile + i, nfiles * sizeof(struct file *) - i);
		bcopy(fdp->fd_ofileflags, newofileflags,
			(i = sizeof(char) * fdp->fd_nfiles));
		bzero(newofileflags + i, nfiles * sizeof(char) - i);

		if (fdp->fd_nfiles > NDFILE)
			free(fdp->fd_ofiles, M_FILEDESC);

		if (NDHISLOTS(nfiles) > NDHISLOTS(fdp->fd_nfiles)) {
			newhimap = malloc(NDHISLOTS(nfiles) * sizeof(u_int),
			    M_FILEDESC, M_WAITOK);
			newlomap = malloc( NDLOSLOTS(nfiles) * sizeof(u_int),
			    M_FILEDESC, M_WAITOK);

			bcopy(fdp->fd_himap, newhimap,
			    (i = NDHISLOTS(fdp->fd_nfiles) * sizeof(u_int)));
			bzero((char *)newhimap + i,
			    NDHISLOTS(nfiles) * sizeof(u_int) - i);

			bcopy(fdp->fd_lomap, newlomap,
			    (i = NDLOSLOTS(fdp->fd_nfiles) * sizeof(u_int)));
			bzero((char *)newlomap + i,
			    NDLOSLOTS(nfiles) * sizeof(u_int) - i);

			if (NDHISLOTS(fdp->fd_nfiles) > NDHISLOTS(NDFILE)) {
				free(fdp->fd_himap, M_FILEDESC);
				free(fdp->fd_lomap, M_FILEDESC);
			}
			fdp->fd_himap = newhimap;
			fdp->fd_lomap = newlomap;
		}
		fdp->fd_ofiles = newofile;
		fdp->fd_ofileflags = newofileflags;
		fdp->fd_nfiles = nfiles;
		fdexpand++;
	}
}

/*
 * Check to see whether n user file descriptors
 * are available to the process p.
 */
int
fdavail(p, n)
	struct proc *p;
	register int n;
{
	register struct filedesc *fdp = p->p_fd;
	register struct file **fpp;
	register int i, lim;

	lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
	if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0)
		return (1);
	fpp = &fdp->fd_ofiles[fdp->fd_freefile];
	for (i = min(lim, fdp->fd_nfiles) - fdp->fd_freefile; --i >= 0; fpp++)
		if (*fpp == NULL && --n <= 0)
			return (1);
	return (0);
}

/*
 * Create a new open file structure and allocate
 * a file decriptor for the process that refers to it.
 */
int
falloc(p, resultfp, resultfd)
	register struct proc *p;
	struct file **resultfp;
	int *resultfd;
{
	register struct file *fp, *fq;
	int error, i;

	if ((error = fdalloc(p, 0, &i)) != 0)
		return (error);
	if (nfiles >= maxfiles) {
		fd_unused(p->p_fd, i);
		tablefull("file");
		return (ENFILE);
	}
	/*
	 * Allocate a new file descriptor.
	 * If the process has file descriptor zero open, add to the list
	 * of open files at that point, otherwise put it at the front of
	 * the list of open files.
	 */
	nfiles++;
	fp = pool_get(&file_pool, PR_WAITOK);
	bzero(fp, sizeof(struct file));
	if ((fq = p->p_fd->fd_ofiles[0]) != NULL) {
		LIST_INSERT_AFTER(fq, fp, f_list);
	} else {
		LIST_INSERT_HEAD(&filehead, fp, f_list);
	}
	p->p_fd->fd_ofiles[i] = fp;
	fp->f_count = 1;
	fp->f_cred = p->p_ucred;
	crhold(fp->f_cred);
	if (resultfp)
		*resultfp = fp;
	if (resultfd)
		*resultfd = i;
	return (0);
}

/*
 * Free a file descriptor.
 */
void
ffree(fp)
	register struct file *fp;
{
	LIST_REMOVE(fp, f_list);
	crfree(fp->f_cred);
#ifdef DIAGNOSTIC
	fp->f_count = 0;
#endif
	nfiles--;
	pool_put(&file_pool, fp);
}

/*
 * Build a new filedesc structure.
 */
struct filedesc *
fdinit(p)
	struct proc *p;
{
	register struct filedesc0 *newfdp;
	register struct filedesc *fdp = p->p_fd;
	extern int cmask;

	newfdp = pool_get(&fdesc_pool, PR_WAITOK);
	bzero(newfdp, sizeof(struct filedesc0));
	newfdp->fd_fd.fd_cdir = fdp->fd_cdir;
	VREF(newfdp->fd_fd.fd_cdir);
	newfdp->fd_fd.fd_rdir = fdp->fd_rdir;
	if (newfdp->fd_fd.fd_rdir)
		VREF(newfdp->fd_fd.fd_rdir);

	/* Create the file descriptor table. */
	newfdp->fd_fd.fd_refcnt = 1;
	newfdp->fd_fd.fd_cmask = cmask;
	newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles;
	newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags;
	newfdp->fd_fd.fd_nfiles = NDFILE;
	newfdp->fd_fd.fd_himap = newfdp->fd_dhimap;
	newfdp->fd_fd.fd_lomap = newfdp->fd_dlomap;
	newfdp->fd_fd.fd_knlistsize = -1;

	newfdp->fd_fd.fd_freefile = 0;
	newfdp->fd_fd.fd_lastfile = 0;

	return (&newfdp->fd_fd);
}

/*
 * Share a filedesc structure.
 */
struct filedesc *
fdshare(p)
	struct proc *p;
{
	p->p_fd->fd_refcnt++;
	return (p->p_fd);
}

/*
 * Copy a filedesc structure.
 */
struct filedesc *
fdcopy(p)
	struct proc *p;
{
	struct filedesc *newfdp, *fdp = p->p_fd;
	struct file **fpp;
	int i;

	newfdp = pool_get(&fdesc_pool, PR_WAITOK);
	bcopy(fdp, newfdp, sizeof(struct filedesc));
	if (newfdp->fd_cdir)
		VREF(newfdp->fd_cdir);
	if (newfdp->fd_rdir)
		VREF(newfdp->fd_rdir);
	newfdp->fd_refcnt = 1;

	/*
	 * If the number of open files fits in the internal arrays
	 * of the open file structure, use them, otherwise allocate
	 * additional memory for the number of descriptors currently
	 * in use.
	 */
	if (newfdp->fd_lastfile < NDFILE) {
		newfdp->fd_ofiles = ((struct filedesc0 *) newfdp)->fd_dfiles;
		newfdp->fd_ofileflags =
		    ((struct filedesc0 *) newfdp)->fd_dfileflags;
		i = NDFILE;
	} else {
		/*
		 * Compute the smallest multiple of NDEXTENT needed
		 * for the file descriptors currently in use,
		 * allowing the table to shrink.
		 */
		i = newfdp->fd_nfiles;
		while (i >= 2 * NDEXTENT && i > newfdp->fd_lastfile * 2)
			i /= 2;
		newfdp->fd_ofiles = malloc(i * OFILESIZE, M_FILEDESC, M_WAITOK);
		newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i];
	}
	if (NDHISLOTS(i) <= NDHISLOTS(NDFILE)) {
		newfdp->fd_himap =
			((struct filedesc0 *) newfdp)->fd_dhimap;
		newfdp->fd_lomap =
			((struct filedesc0 *) newfdp)->fd_dlomap;
	} else {
		newfdp->fd_himap = malloc(NDHISLOTS(i) * sizeof(u_int),
		    M_FILEDESC, M_WAITOK);
		newfdp->fd_lomap = malloc(NDLOSLOTS(i) * sizeof(u_int),
		    M_FILEDESC, M_WAITOK);
	}
	newfdp->fd_nfiles = i;
	bcopy(fdp->fd_ofiles, newfdp->fd_ofiles, i * sizeof(struct file **));
	bcopy(fdp->fd_ofileflags, newfdp->fd_ofileflags, i * sizeof(char));
	bcopy(fdp->fd_himap, newfdp->fd_himap, NDHISLOTS(i) * sizeof(u_int));
	bcopy(fdp->fd_lomap, newfdp->fd_lomap, NDLOSLOTS(i) * sizeof(u_int));

	/*
	 * kq descriptors cannot be copied.
	 */
	if (newfdp->fd_knlistsize != -1) {
		fpp = newfdp->fd_ofiles;
		for (i = 0; i <= newfdp->fd_lastfile; i++, fpp++)
			if (*fpp != NULL && (*fpp)->f_type == DTYPE_KQUEUE)
				fdremove(newfdp, i);
		newfdp->fd_knlist = NULL;
		newfdp->fd_knlistsize = -1;
		newfdp->fd_knhash = NULL;
		newfdp->fd_knhashmask = 0;
	}

	fpp = newfdp->fd_ofiles;
	for (i = 0; i <= newfdp->fd_lastfile; i++, fpp++)
		if (*fpp != NULL) {
			/*
			 * XXX Gruesome hack. If count gets too high, fail
			 * to copy an fd, since fdcopy()'s callers do not
			 * permit it to indicate failure yet.
			 */
			if ((*fpp)->f_count == LONG_MAX-2)
				fdremove(newfdp, i);
			else
				(*fpp)->f_count++;
		}
	return (newfdp);
}

/*
 * Release a filedesc structure.
 */
void
fdfree(p)
	struct proc *p;
{
	register struct filedesc *fdp = p->p_fd;
	register struct file **fpp, *fp;
	register int i;

	if (--fdp->fd_refcnt > 0)
		return;
	fpp = fdp->fd_ofiles;
	for (i = fdp->fd_lastfile; i >= 0; i--, fpp++) {
		fp = *fpp;
		if (fp != NULL) {
			*fpp = NULL;
			(void) closef(fp, p);
		}
	}
	p->p_fd = NULL;
	if (fdp->fd_nfiles > NDFILE)
		free(fdp->fd_ofiles, M_FILEDESC);
	if (NDHISLOTS(fdp->fd_nfiles) > NDHISLOTS(NDFILE)) {
		free(fdp->fd_himap, M_FILEDESC);
		free(fdp->fd_lomap, M_FILEDESC);
	}
	if (fdp->fd_cdir)
		vrele(fdp->fd_cdir);
	if (fdp->fd_rdir)
		vrele(fdp->fd_rdir);
	if (fdp->fd_knlist)
		FREE(fdp->fd_knlist, M_TEMP);
	if (fdp->fd_knhash)
		FREE(fdp->fd_knhash, M_TEMP);
	pool_put(&fdesc_pool, fdp);
}

/*
 * Internal form of close.
 * Decrement reference count on file structure.
 * Note: p may be NULL when closing a file
 * that was being passed in a message.
 */
int
closef(fp, p)
	register struct file *fp;
	register struct proc *p;
{
	struct vnode *vp;
	struct flock lf;
	int error;

	if (fp == NULL)
		return (0);
	/*
	 * POSIX record locking dictates that any close releases ALL
	 * locks owned by this process.  This is handled by setting
	 * a flag in the unlock to free ONLY locks obeying POSIX
	 * semantics, and not to free BSD-style file locks.
	 * If the descriptor was in a message, POSIX-style locks
	 * aren't passed with the descriptor.
	 */
	if (p && (p->p_flag & P_ADVLOCK) && fp->f_type == DTYPE_VNODE) {
		lf.l_whence = SEEK_SET;
		lf.l_start = 0;
		lf.l_len = 0;
		lf.l_type = F_UNLCK;
		vp = (struct vnode *)fp->f_data;
		(void) VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_POSIX);
	}
	if (--fp->f_count > 0)
		return (0);
	if (fp->f_count < 0)
		panic("closef: count < 0");
	if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) {
		lf.l_whence = SEEK_SET;
		lf.l_start = 0;
		lf.l_len = 0;
		lf.l_type = F_UNLCK;
		vp = (struct vnode *)fp->f_data;
		(void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
	}
	if (fp->f_ops)
		error = (*fp->f_ops->fo_close)(fp, p);
	else
		error = 0;
	ffree(fp);
	return (error);
}

/*
 * Apply an advisory lock on a file descriptor.
 *
 * Just attempt to get a record lock of the requested type on
 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0).
 */
/* ARGSUSED */
int
sys_flock(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_flock_args /* {
		syscallarg(int) fd;
		syscallarg(int) how;
	} */ *uap = v;
	int fd = SCARG(uap, fd);
	int how = SCARG(uap, how);
	register struct filedesc *fdp = p->p_fd;
	register struct file *fp;
	struct vnode *vp;
	struct flock lf;

	if ((u_int)fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[fd]) == NULL)
		return (EBADF);
	if (fp->f_type != DTYPE_VNODE)
		return (EOPNOTSUPP);
	vp = (struct vnode *)fp->f_data;
	lf.l_whence = SEEK_SET;
	lf.l_start = 0;
	lf.l_len = 0;
	if (how & LOCK_UN) {
		lf.l_type = F_UNLCK;
		fp->f_flag &= ~FHASLOCK;
		return (VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK));
	}
	if (how & LOCK_EX)
		lf.l_type = F_WRLCK;
	else if (how & LOCK_SH)
		lf.l_type = F_RDLCK;
	else
		return (EINVAL);
	fp->f_flag |= FHASLOCK;
	if (how & LOCK_NB)
		return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK));
	return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK|F_WAIT));
}

/*
 * File Descriptor pseudo-device driver (/dev/fd/).
 *
 * Opening minor device N dup()s the file (if any) connected to file
 * descriptor N belonging to the calling process.  Note that this driver
 * consists of only the ``open()'' routine, because all subsequent
 * references to this file will be direct to the other driver.
 */
/* ARGSUSED */
int
filedescopen(dev, mode, type, p)
	dev_t dev;
	int mode, type;
	struct proc *p;
{

	/*
	 * XXX Kludge: set curproc->p_dupfd to contain the value of the
	 * the file descriptor being sought for duplication. The error
	 * return ensures that the vnode for this device will be released
	 * by vn_open. Open will detect this special error and take the
	 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
	 * will simply report the error.
	 */
	p->p_dupfd = minor(dev);
	return (ENODEV);
}

/*
 * Duplicate the specified descriptor to a free descriptor.
 */
int
dupfdopen(fdp, indx, dfd, mode, error)
	register struct filedesc *fdp;
	register int indx, dfd;
	int mode;
	int error;
{
	register struct file *wfp;
	struct file *fp;

	/*
	 * If the to-be-dup'd fd number is greater than the allowed number
	 * of file descriptors, or the fd to be dup'd has already been
	 * closed, reject.  Note, check for new == old is necessary as
	 * falloc could allocate an already closed to-be-dup'd descriptor
	 * as the new descriptor.
	 */
	fp = fdp->fd_ofiles[indx];
	if ((u_int)dfd >= fdp->fd_nfiles ||
	    (wfp = fdp->fd_ofiles[dfd]) == NULL || fp == wfp)
		return (EBADF);

	/*
	 * There are two cases of interest here.
	 *
	 * For ENODEV simply dup (dfd) to file descriptor
	 * (indx) and return.
	 *
	 * For ENXIO steal away the file structure from (dfd) and
	 * store it in (indx).  (dfd) is effectively closed by
	 * this operation.
	 *
	 * Any other error code is just returned.
	 */
	switch (error) {
	case ENODEV:
		/*
		 * Check that the mode the file is being opened for is a
		 * subset of the mode of the existing descriptor.
		 */
		if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag)
			return (EACCES);
		if (wfp->f_count == LONG_MAX-2)
			return (EDEADLK);
		fdp->fd_ofiles[indx] = wfp;
		fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
		wfp->f_count++;
		fd_used(fdp, indx);
		return (0);

	case ENXIO:
		/*
		 * Steal away the file pointer from dfd, and stuff it into indx.
		 */
		fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd];
		fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
		fdp->fd_ofiles[dfd] = NULL;
		fdp->fd_ofileflags[dfd] = 0;
		/*
		 * Complete the clean up of the filedesc structure by
		 * recomputing the various hints.
		 */
		fd_used(fdp, indx);
		fd_unused(fdp, dfd);
		return (0);

	default:
		return (error);
	}
	/* NOTREACHED */
}

/*
 * Close any files on exec?
 */
void
fdcloseexec(p)
	struct proc *p;
{
	register struct filedesc *fdp = p->p_fd;
	register int fd;

	for (fd = 0; fd <= fdp->fd_lastfile; fd++)
		if (fdp->fd_ofileflags[fd] & UF_EXCLOSE)
			(void) fdrelease(p, fd);
}