xref: /netbsd-src/sys/miscfs/fdesc/fdesc_vnops.c (revision 9fb66d812c00ebfb445c0b47dea128f32aa6fe96)
1 /*	$NetBSD: fdesc_vnops.c,v 1.134 2020/06/27 17:29:19 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software donated to Berkeley by
8  * Jan-Simon Pendry.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)fdesc_vnops.c	8.17 (Berkeley) 5/22/95
35  *
36  * #Id: fdesc_vnops.c,v 1.12 1993/04/06 16:17:17 jsp Exp #
37  */
38 
39 /*
40  * /dev/fd Filesystem
41  */
42 
43 #include <sys/cdefs.h>
44 __KERNEL_RCSID(0, "$NetBSD: fdesc_vnops.c,v 1.134 2020/06/27 17:29:19 christos Exp $");
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/time.h>
49 #include <sys/proc.h>
50 #include <sys/resourcevar.h>
51 #include <sys/socketvar.h>
52 #include <sys/filedesc.h>
53 #include <sys/vnode.h>
54 #include <sys/malloc.h>
55 #include <sys/conf.h>
56 #include <sys/file.h>
57 #include <sys/stat.h>
58 #include <sys/mount.h>
59 #include <sys/namei.h>
60 #include <sys/buf.h>
61 #include <sys/dirent.h>
62 #include <sys/tty.h>
63 #include <sys/kauth.h>
64 #include <sys/atomic.h>
65 
66 #include <miscfs/fdesc/fdesc.h>
67 #include <miscfs/genfs/genfs.h>
68 
69 #define cttyvp(p) ((p)->p_lflag & PL_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
70 
71 dev_t devctty;
72 
73 #if (FD_STDIN != FD_STDOUT-1) || (FD_STDOUT != FD_STDERR-1)
74 FD_STDIN, FD_STDOUT, FD_STDERR must be a sequence n, n+1, n+2
75 #endif
76 
77 int	fdesc_lookup(void *);
78 #define	fdesc_create	genfs_eopnotsupp
79 #define	fdesc_mknod	genfs_eopnotsupp
80 int	fdesc_open(void *);
81 #define	fdesc_close	genfs_nullop
82 #define	fdesc_access	genfs_nullop
83 int	fdesc_getattr(void *);
84 int	fdesc_setattr(void *);
85 int	fdesc_read(void *);
86 int	fdesc_write(void *);
87 int	fdesc_ioctl(void *);
88 int	fdesc_poll(void *);
89 int	fdesc_kqfilter(void *);
90 #define	fdesc_mmap	genfs_eopnotsupp
91 #define	fdesc_fcntl	genfs_fcntl
92 #define	fdesc_fsync	genfs_nullop
93 #define	fdesc_seek	genfs_seek
94 #define	fdesc_remove	genfs_eopnotsupp
95 int	fdesc_link(void *);
96 #define	fdesc_rename	genfs_eopnotsupp
97 #define	fdesc_mkdir	genfs_eopnotsupp
98 #define	fdesc_rmdir	genfs_eopnotsupp
99 int	fdesc_symlink(void *);
100 int	fdesc_readdir(void *);
101 int	fdesc_readlink(void *);
102 #define	fdesc_abortop	genfs_abortop
103 int	fdesc_inactive(void *);
104 int	fdesc_reclaim(void *);
105 #define	fdesc_lock	genfs_lock
106 #define	fdesc_unlock	genfs_unlock
107 #define	fdesc_bmap	genfs_badop
108 #define	fdesc_strategy	genfs_badop
109 int	fdesc_print(void *);
110 int	fdesc_pathconf(void *);
111 #define	fdesc_islocked	genfs_islocked
112 #define	fdesc_advlock	genfs_einval
113 #define	fdesc_bwrite	genfs_eopnotsupp
114 #define fdesc_revoke	genfs_revoke
115 #define fdesc_putpages	genfs_null_putpages
116 
117 static int fdesc_attr(int, struct vattr *, kauth_cred_t);
118 
119 int (**fdesc_vnodeop_p)(void *);
120 const struct vnodeopv_entry_desc fdesc_vnodeop_entries[] = {
121 	{ &vop_default_desc, vn_default_error },
122 	{ &vop_lookup_desc, fdesc_lookup },		/* lookup */
123 	{ &vop_create_desc, fdesc_create },		/* create */
124 	{ &vop_mknod_desc, fdesc_mknod },		/* mknod */
125 	{ &vop_open_desc, fdesc_open },			/* open */
126 	{ &vop_close_desc, fdesc_close },		/* close */
127 	{ &vop_access_desc, fdesc_access },		/* access */
128 	{ &vop_accessx_desc, genfs_accessx },		/* accessx */
129 	{ &vop_getattr_desc, fdesc_getattr },		/* getattr */
130 	{ &vop_setattr_desc, fdesc_setattr },		/* setattr */
131 	{ &vop_read_desc, fdesc_read },			/* read */
132 	{ &vop_write_desc, fdesc_write },		/* write */
133 	{ &vop_fallocate_desc, genfs_eopnotsupp },	/* fallocate */
134 	{ &vop_fdiscard_desc, genfs_eopnotsupp },	/* fdiscard */
135 	{ &vop_ioctl_desc, fdesc_ioctl },		/* ioctl */
136 	{ &vop_fcntl_desc, fdesc_fcntl },		/* fcntl */
137 	{ &vop_poll_desc, fdesc_poll },			/* poll */
138 	{ &vop_kqfilter_desc, fdesc_kqfilter },		/* kqfilter */
139 	{ &vop_revoke_desc, fdesc_revoke },		/* revoke */
140 	{ &vop_mmap_desc, fdesc_mmap },			/* mmap */
141 	{ &vop_fsync_desc, fdesc_fsync },		/* fsync */
142 	{ &vop_seek_desc, fdesc_seek },			/* seek */
143 	{ &vop_remove_desc, fdesc_remove },		/* remove */
144 	{ &vop_link_desc, fdesc_link },			/* link */
145 	{ &vop_rename_desc, fdesc_rename },		/* rename */
146 	{ &vop_mkdir_desc, fdesc_mkdir },		/* mkdir */
147 	{ &vop_rmdir_desc, fdesc_rmdir },		/* rmdir */
148 	{ &vop_symlink_desc, fdesc_symlink },		/* symlink */
149 	{ &vop_readdir_desc, fdesc_readdir },		/* readdir */
150 	{ &vop_readlink_desc, fdesc_readlink },		/* readlink */
151 	{ &vop_abortop_desc, fdesc_abortop },		/* abortop */
152 	{ &vop_inactive_desc, fdesc_inactive },		/* inactive */
153 	{ &vop_reclaim_desc, fdesc_reclaim },		/* reclaim */
154 	{ &vop_lock_desc, fdesc_lock },			/* lock */
155 	{ &vop_unlock_desc, fdesc_unlock },		/* unlock */
156 	{ &vop_bmap_desc, fdesc_bmap },			/* bmap */
157 	{ &vop_strategy_desc, fdesc_strategy },		/* strategy */
158 	{ &vop_print_desc, fdesc_print },		/* print */
159 	{ &vop_islocked_desc, fdesc_islocked },		/* islocked */
160 	{ &vop_pathconf_desc, fdesc_pathconf },		/* pathconf */
161 	{ &vop_advlock_desc, fdesc_advlock },		/* advlock */
162 	{ &vop_bwrite_desc, fdesc_bwrite },		/* bwrite */
163 	{ &vop_putpages_desc, fdesc_putpages },		/* putpages */
164 	{ NULL, NULL }
165 };
166 
167 const struct vnodeopv_desc fdesc_vnodeop_opv_desc =
168 	{ &fdesc_vnodeop_p, fdesc_vnodeop_entries };
169 
170 /*
171  * Initialise cache headers
172  */
173 void
174 fdesc_init(void)
175 {
176 	int cttymajor;
177 
178 	/* locate the major number */
179 	cttymajor = devsw_name2chr("ctty", NULL, 0);
180 	devctty = makedev(cttymajor, 0);
181 }
182 
183 void
184 fdesc_done(void)
185 {
186 }
187 
188 /*
189  * vp is the current namei directory
190  * ndp is the name to locate in that directory...
191  */
192 int
193 fdesc_lookup(void *v)
194 {
195 	struct vop_lookup_v2_args /* {
196 		struct vnode * a_dvp;
197 		struct vnode ** a_vpp;
198 		struct componentname * a_cnp;
199 	} */ *ap = v;
200 	struct vnode **vpp = ap->a_vpp;
201 	struct vnode *dvp = ap->a_dvp;
202 	struct componentname *cnp = ap->a_cnp;
203 	struct lwp *l = curlwp;
204 	const char *pname = cnp->cn_nameptr;
205 	struct proc *p = l->l_proc;
206 	unsigned fd = 0;
207 	int error, ix = -1;
208 	fdtab_t *dt;
209 
210 	dt = atomic_load_consume(&curlwp->l_fd->fd_dt);
211 
212 	if (cnp->cn_namelen == 1 && *pname == '.') {
213 		*vpp = dvp;
214 		vref(dvp);
215 		return (0);
216 	}
217 
218 	switch (VTOFDESC(dvp)->fd_type) {
219 	default:
220 	case Flink:
221 	case Fdesc:
222 	case Fctty:
223 		error = ENOTDIR;
224 		goto bad;
225 
226 	case Froot:
227 		if (cnp->cn_namelen == 2 && memcmp(pname, "fd", 2) == 0) {
228 			ix = FD_DEVFD;
229 			goto good;
230 		}
231 
232 		if (cnp->cn_namelen == 3 && memcmp(pname, "tty", 3) == 0) {
233 			struct vnode *ttyvp = cttyvp(p);
234 			if (ttyvp == NULL) {
235 				error = ENXIO;
236 				goto bad;
237 			}
238 			ix = FD_CTTY;
239 			goto good;
240 		}
241 
242 		switch (cnp->cn_namelen) {
243 		case 5:
244 			if (memcmp(pname, "stdin", 5) == 0) {
245 				ix = FD_STDIN;
246 				goto good;
247 			}
248 			break;
249 		case 6:
250 			if (memcmp(pname, "stdout", 6) == 0) {
251 				ix = FD_STDOUT;
252 				goto good;
253 			} else if (memcmp(pname, "stderr", 6) == 0) {
254 				ix = FD_STDERR;
255 				goto good;
256 			}
257 			break;
258 		}
259 
260 		error = ENOENT;
261 		goto bad;
262 
263 	case Fdevfd:
264 		if (cnp->cn_namelen == 2 && memcmp(pname, "..", 2) == 0) {
265 			ix = FD_ROOT;
266 			goto good;
267 		}
268 
269 		fd = 0;
270 		while (*pname >= '0' && *pname <= '9') {
271 			fd = 10 * fd + *pname++ - '0';
272 			if (fd >= dt->dt_nfiles)
273 				break;
274 		}
275 
276 		if (*pname != '\0') {
277 			error = ENOENT;
278 			goto bad;
279 		}
280 
281 		if (fd >= dt->dt_nfiles || dt->dt_ff[fd] == NULL ||
282 		    dt->dt_ff[fd]->ff_file == NULL) {
283 			error = EBADF;
284 			goto bad;
285 		}
286 
287 		ix = FD_DESC + fd;
288 		goto good;
289 	}
290 
291 bad:
292 	*vpp = NULL;
293 	return error;
294 
295 good:
296 	KASSERT(ix != -1);
297 	error = vcache_get(dvp->v_mount, &ix, sizeof(ix), vpp);
298 	if (error == 0 && ix == FD_CTTY)
299 		(*vpp)->v_type = VCHR;
300 	return error;
301 }
302 
303 int
304 fdesc_open(void *v)
305 {
306 	struct vop_open_args /* {
307 		struct vnode *a_vp;
308 		int  a_mode;
309 		kauth_cred_t a_cred;
310 	} */ *ap = v;
311 	struct vnode *vp = ap->a_vp;
312 
313 	switch (VTOFDESC(vp)->fd_type) {
314 	case Fdesc:
315 		/*
316 		 * XXX Kludge: set dupfd to contain the value of the
317 		 * the file descriptor being sought for duplication. The error
318 		 * return ensures that the vnode for this device will be
319 		 * released by vn_open. Open will detect this special error and
320 		 * take the actions in dupfdopen.  Other callers of vn_open or
321 		 * VOP_OPEN will simply report the error.
322 		 */
323 		curlwp->l_dupfd = VTOFDESC(vp)->fd_fd;	/* XXX */
324 		return EDUPFD;
325 
326 	case Fctty:
327 		return cdev_open(devctty, ap->a_mode, 0, curlwp);
328 	case Froot:
329 	case Fdevfd:
330 	case Flink:
331 		break;
332 	}
333 
334 	return (0);
335 }
336 
337 static int
338 fdesc_attr(int fd, struct vattr *vap, kauth_cred_t cred)
339 {
340 	file_t *fp;
341 	struct stat stb;
342 	int error;
343 
344 	if ((fp = fd_getfile(fd)) == NULL)
345 		return (EBADF);
346 
347 	switch (fp->f_type) {
348 	case DTYPE_VNODE:
349 		vn_lock(fp->f_vnode, LK_SHARED | LK_RETRY);
350 		error = VOP_GETATTR(fp->f_vnode, vap, cred);
351 		VOP_UNLOCK(fp->f_vnode);
352 		if (error == 0 && vap->va_type == VDIR) {
353 			/*
354 			 * directories can cause loops in the namespace,
355 			 * so turn off the 'x' bits to avoid trouble.
356 			 */
357 			vap->va_mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
358 		}
359 		break;
360 
361 	default:
362 		memset(&stb, 0, sizeof(stb));
363 		error = (*fp->f_ops->fo_stat)(fp, &stb);
364 		if (error)
365 			break;
366 
367 		vattr_null(vap);
368 		switch(fp->f_type) {
369 		case DTYPE_SOCKET:
370 			vap->va_type = VSOCK;
371 			break;
372 		case DTYPE_PIPE:
373 			vap->va_type = VFIFO;
374 			break;
375 		default:
376 			/* use VNON perhaps? */
377 			vap->va_type = VBAD;
378 			break;
379 		}
380 		vap->va_mode = stb.st_mode;
381 		vap->va_nlink = stb.st_nlink;
382 		vap->va_uid = stb.st_uid;
383 		vap->va_gid = stb.st_gid;
384 		vap->va_fsid = stb.st_dev;
385 		vap->va_fileid = stb.st_ino;
386 		vap->va_size = stb.st_size;
387 		vap->va_blocksize = stb.st_blksize;
388 		vap->va_atime = stb.st_atimespec;
389 		vap->va_mtime = stb.st_mtimespec;
390 		vap->va_ctime = stb.st_ctimespec;
391 		vap->va_gen = stb.st_gen;
392 		vap->va_flags = stb.st_flags;
393 		vap->va_rdev = stb.st_rdev;
394 		vap->va_bytes = stb.st_blocks * stb.st_blksize;
395 		break;
396 	}
397 
398 	fd_putfile(fd);
399 	return (error);
400 }
401 
402 int
403 fdesc_getattr(void *v)
404 {
405 	struct vop_getattr_args /* {
406 		struct vnode *a_vp;
407 		struct vattr *a_vap;
408 		kauth_cred_t a_cred;
409 		struct lwp *a_l;
410 	} */ *ap = v;
411 	struct vnode *vp = ap->a_vp;
412 	struct vattr *vap = ap->a_vap;
413 	unsigned fd;
414 	int error = 0;
415 	struct timeval tv;
416 
417 	switch (VTOFDESC(vp)->fd_type) {
418 	case Froot:
419 	case Fdevfd:
420 	case Flink:
421 	case Fctty:
422 		vattr_null(vap);
423 		vap->va_fileid = VTOFDESC(vp)->fd_ix;
424 
425 #define R_ALL (S_IRUSR|S_IRGRP|S_IROTH)
426 #define W_ALL (S_IWUSR|S_IWGRP|S_IWOTH)
427 #define X_ALL (S_IXUSR|S_IXGRP|S_IXOTH)
428 
429 		switch (VTOFDESC(vp)->fd_type) {
430 		case Flink:
431 			vap->va_mode = R_ALL|X_ALL;
432 			vap->va_type = VLNK;
433 			vap->va_rdev = 0;
434 			vap->va_nlink = 1;
435 			vap->va_size = strlen(VTOFDESC(vp)->fd_link);
436 			break;
437 
438 		case Fctty:
439 			vap->va_mode = R_ALL|W_ALL;
440 			vap->va_type = VCHR;
441 			vap->va_rdev = devctty;
442 			vap->va_nlink = 1;
443 			vap->va_size = 0;
444 			break;
445 
446 		default:
447 			vap->va_mode = R_ALL|X_ALL;
448 			vap->va_type = VDIR;
449 			vap->va_rdev = 0;
450 			vap->va_nlink = 2;
451 			vap->va_size = DEV_BSIZE;
452 			break;
453 		}
454 		vap->va_uid = 0;
455 		vap->va_gid = 0;
456 		vap->va_fsid = vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0];
457 		vap->va_blocksize = DEV_BSIZE;
458 		getmicroboottime(&tv);
459 		vap->va_atime.tv_sec = tv.tv_sec;
460 		vap->va_atime.tv_nsec = 0;
461 		vap->va_mtime = vap->va_atime;
462 		vap->va_ctime = vap->va_mtime;
463 		vap->va_gen = 0;
464 		vap->va_flags = 0;
465 		vap->va_bytes = 0;
466 		break;
467 
468 	case Fdesc:
469 		fd = VTOFDESC(vp)->fd_fd;
470 		error = fdesc_attr(fd, vap, ap->a_cred);
471 		break;
472 
473 	default:
474 		panic("fdesc_getattr");
475 		break;
476 	}
477 
478 	if (error == 0)
479 		vp->v_type = vap->va_type;
480 
481 	return (error);
482 }
483 
484 int
485 fdesc_setattr(void *v)
486 {
487 	struct vop_setattr_args /* {
488 		struct vnode *a_vp;
489 		struct vattr *a_vap;
490 		kauth_cred_t a_cred;
491 	} */ *ap = v;
492 	file_t *fp;
493 	unsigned fd;
494 
495 	/*
496 	 * Can't mess with the root vnode
497 	 */
498 	switch (VTOFDESC(ap->a_vp)->fd_type) {
499 	case Fdesc:
500 		break;
501 
502 	case Fctty:
503 		return (0);
504 
505 	default:
506 		return (EACCES);
507 	}
508 
509 	fd = VTOFDESC(ap->a_vp)->fd_fd;
510 	if ((fp = fd_getfile(fd)) == NULL)
511 		return (EBADF);
512 
513 	/*
514 	 * XXX: Can't reasonably set the attr's on any types currently.
515 	 *      On vnode's this will cause truncation and socket/pipes make
516 	 *      no sense.
517 	 */
518 	fd_putfile(fd);
519 	return (0);
520 }
521 
522 
523 struct fdesc_target {
524 	ino_t ft_fileno;
525 	u_char ft_type;
526 	u_char ft_namlen;
527 	const char *ft_name;
528 } fdesc_targets[] = {
529 #define N(s) sizeof(s)-1, s
530 	{ FD_DEVFD,  DT_DIR,     N("fd")     },
531 	{ FD_STDIN,  DT_LNK,     N("stdin")  },
532 	{ FD_STDOUT, DT_LNK,     N("stdout") },
533 	{ FD_STDERR, DT_LNK,     N("stderr") },
534 	{ FD_CTTY,   DT_UNKNOWN, N("tty")    },
535 #undef N
536 #define UIO_MX _DIRENT_RECLEN((struct dirent *)NULL, sizeof("stderr") - 1)
537 };
538 static int nfdesc_targets = sizeof(fdesc_targets) / sizeof(fdesc_targets[0]);
539 
540 int
541 fdesc_readdir(void *v)
542 {
543 	struct vop_readdir_args /* {
544 		struct vnode *a_vp;
545 		struct uio *a_uio;
546 		kauth_cred_t a_cred;
547 		int *a_eofflag;
548 		off_t **a_cookies;
549 		int *a_ncookies;
550 	} */ *ap = v;
551 	struct uio *uio = ap->a_uio;
552 	struct dirent d;
553 	off_t i;
554 	int j;
555 	int error;
556 	off_t *cookies = NULL;
557 	int ncookies;
558 	fdtab_t *dt;
559 
560 	switch (VTOFDESC(ap->a_vp)->fd_type) {
561 	case Fctty:
562 		return 0;
563 
564 	case Fdesc:
565 		return ENOTDIR;
566 
567 	default:
568 		break;
569 	}
570 
571 	dt = atomic_load_consume(&curlwp->l_fd->fd_dt);
572 
573 	if (uio->uio_resid < UIO_MX)
574 		return EINVAL;
575 	if (uio->uio_offset < 0)
576 		return EINVAL;
577 
578 	error = 0;
579 	i = uio->uio_offset;
580 	(void)memset(&d, 0, UIO_MX);
581 	d.d_reclen = UIO_MX;
582 	if (ap->a_ncookies)
583 		ncookies = uio->uio_resid / UIO_MX;
584 	else
585 		ncookies = 0;
586 
587 	if (VTOFDESC(ap->a_vp)->fd_type == Froot) {
588 		struct fdesc_target *ft;
589 
590 		if (i >= nfdesc_targets)
591 			return 0;
592 
593 		if (ap->a_ncookies) {
594 			ncookies = uimin(ncookies, (nfdesc_targets - i));
595 			cookies = malloc(ncookies * sizeof(off_t),
596 			    M_TEMP, M_WAITOK);
597 			*ap->a_cookies = cookies;
598 			*ap->a_ncookies = ncookies;
599 		}
600 
601 		for (ft = &fdesc_targets[i]; uio->uio_resid >= UIO_MX &&
602 		    i < nfdesc_targets; ft++, i++) {
603 			switch (ft->ft_fileno) {
604 			case FD_CTTY:
605 				if (cttyvp(curproc) == NULL)
606 					continue;
607 				break;
608 
609 			case FD_STDIN:
610 			case FD_STDOUT:
611 			case FD_STDERR:
612 				if ((ft->ft_fileno - FD_STDIN) >=
613 				    dt->dt_nfiles)
614 					continue;
615 				if (dt->dt_ff[ft->ft_fileno - FD_STDIN]
616 				    == NULL || dt->dt_ff[ft->ft_fileno -
617 				    FD_STDIN]->ff_file == NULL)
618 					continue;
619 				break;
620 			}
621 
622 			d.d_fileno = ft->ft_fileno;
623 			d.d_namlen = ft->ft_namlen;
624 			(void)memcpy(d.d_name, ft->ft_name, ft->ft_namlen + 1);
625 			d.d_type = ft->ft_type;
626 
627 			if ((error = uiomove(&d, UIO_MX, uio)) != 0)
628 				break;
629 			if (cookies)
630 				*cookies++ = i + 1;
631 		}
632 	} else {
633 		if (ap->a_ncookies) {
634 			ncookies = uimin(ncookies, dt->dt_nfiles + 2);
635 			cookies = malloc(ncookies * sizeof(off_t),
636 			    M_TEMP, M_WAITOK);
637 			*ap->a_cookies = cookies;
638 			*ap->a_ncookies = ncookies;
639 		}
640 		for (; i - 2 < dt->dt_nfiles && uio->uio_resid >= UIO_MX; i++) {
641 			switch (i) {
642 			case 0:
643 			case 1:
644 				d.d_fileno = FD_ROOT;		/* XXX */
645 				d.d_namlen = i + 1;
646 				(void)memcpy(d.d_name, "..", d.d_namlen);
647 				d.d_name[i + 1] = '\0';
648 				d.d_type = DT_DIR;
649 				break;
650 
651 			default:
652 				j = (int)i - 2;
653 				if (dt->dt_ff[j] == NULL ||
654 				    dt->dt_ff[j]->ff_file == NULL)
655 					continue;
656 				d.d_fileno = j + FD_STDIN;
657 				d.d_namlen = snprintf(d.d_name,
658 				    sizeof(d.d_name), "%d", j);
659 				d.d_type = DT_UNKNOWN;
660 				break;
661 			}
662 
663 			if ((error = uiomove(&d, UIO_MX, uio)) != 0)
664 				break;
665 			if (cookies)
666 				*cookies++ = i + 1;
667 		}
668 	}
669 
670 	if (ap->a_ncookies && error) {
671 		free(*ap->a_cookies, M_TEMP);
672 		*ap->a_ncookies = 0;
673 		*ap->a_cookies = NULL;
674 	}
675 
676 	uio->uio_offset = i;
677 	return error;
678 }
679 
680 int
681 fdesc_readlink(void *v)
682 {
683 	struct vop_readlink_args /* {
684 		struct vnode *a_vp;
685 		struct uio *a_uio;
686 		kauth_cred_t a_cred;
687 	} */ *ap = v;
688 	struct vnode *vp = ap->a_vp;
689 	int error;
690 
691 	if (vp->v_type != VLNK)
692 		return (EPERM);
693 
694 	if (VTOFDESC(vp)->fd_type == Flink) {
695 		const char *ln = VTOFDESC(vp)->fd_link;
696 		error = uiomove(__UNCONST(ln), strlen(ln), ap->a_uio);
697 	} else {
698 		error = EOPNOTSUPP;
699 	}
700 
701 	return (error);
702 }
703 
704 int
705 fdesc_read(void *v)
706 {
707 	struct vop_read_args /* {
708 		struct vnode *a_vp;
709 		struct uio *a_uio;
710 		int  a_ioflag;
711 		kauth_cred_t a_cred;
712 	} */ *ap = v;
713 	int error = EOPNOTSUPP;
714 	struct vnode *vp = ap->a_vp;
715 
716 	switch (VTOFDESC(vp)->fd_type) {
717 	case Fctty:
718 		VOP_UNLOCK(vp);
719 		error = cdev_read(devctty, ap->a_uio, ap->a_ioflag);
720 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
721 		break;
722 
723 	default:
724 		error = EOPNOTSUPP;
725 		break;
726 	}
727 
728 	return (error);
729 }
730 
731 int
732 fdesc_write(void *v)
733 {
734 	struct vop_write_args /* {
735 		struct vnode *a_vp;
736 		struct uio *a_uio;
737 		int  a_ioflag;
738 		kauth_cred_t a_cred;
739 	} */ *ap = v;
740 	int error = EOPNOTSUPP;
741 	struct vnode *vp = ap->a_vp;
742 
743 	switch (VTOFDESC(vp)->fd_type) {
744 	case Fctty:
745 		VOP_UNLOCK(vp);
746 		error = cdev_write(devctty, ap->a_uio, ap->a_ioflag);
747 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
748 		break;
749 
750 	default:
751 		error = EOPNOTSUPP;
752 		break;
753 	}
754 
755 	return (error);
756 }
757 
758 int
759 fdesc_ioctl(void *v)
760 {
761 	struct vop_ioctl_args /* {
762 		struct vnode *a_vp;
763 		u_long a_command;
764 		void *a_data;
765 		int  a_fflag;
766 		kauth_cred_t a_cred;
767 	} */ *ap = v;
768 	int error = EOPNOTSUPP;
769 
770 	switch (VTOFDESC(ap->a_vp)->fd_type) {
771 	case Fctty:
772 		error = cdev_ioctl(devctty, ap->a_command, ap->a_data,
773 		    ap->a_fflag, curlwp);
774 		break;
775 
776 	default:
777 		error = EOPNOTSUPP;
778 		break;
779 	}
780 
781 	return (error);
782 }
783 
784 int
785 fdesc_poll(void *v)
786 {
787 	struct vop_poll_args /* {
788 		struct vnode *a_vp;
789 		int a_events;
790 	} */ *ap = v;
791 	int revents;
792 
793 	switch (VTOFDESC(ap->a_vp)->fd_type) {
794 	case Fctty:
795 		revents = cdev_poll(devctty, ap->a_events, curlwp);
796 		break;
797 
798 	default:
799 		revents = genfs_poll(v);
800 		break;
801 	}
802 
803 	return (revents);
804 }
805 
806 int
807 fdesc_kqfilter(void *v)
808 {
809 	struct vop_kqfilter_args /* {
810 		struct vnode *a_vp;
811 		struct knote *a_kn;
812 	} */ *ap = v;
813 	int error, fd;
814 	file_t *fp;
815 
816 	switch (VTOFDESC(ap->a_vp)->fd_type) {
817 	case Fctty:
818 		error = cdev_kqfilter(devctty, ap->a_kn);
819 		break;
820 
821 	case Fdesc:
822 		/* just invoke kqfilter for the underlying descriptor */
823 		fd = VTOFDESC(ap->a_vp)->fd_fd;
824 		if ((fp = fd_getfile(fd)) == NULL)
825 			return (1);
826 		error = (*fp->f_ops->fo_kqfilter)(fp, ap->a_kn);
827 		fd_putfile(fd);
828 		break;
829 
830 	default:
831 		return (genfs_kqfilter(v));
832 	}
833 
834 	return (error);
835 }
836 
837 int
838 fdesc_inactive(void *v)
839 {
840 	struct vop_inactive_v2_args /* {
841 		struct vnode *a_vp;
842 	} */ *ap = v;
843 	struct vnode *vp = ap->a_vp;
844 	struct fdescnode *fd = VTOFDESC(vp);
845 
846 	/*
847 	 * Clear out the v_type field to avoid
848 	 * nasty things happening on reclaim.
849 	 */
850 	if (fd->fd_type == Fctty || fd->fd_type == Fdesc)
851 		vp->v_type = VNON;
852 
853 	return (0);
854 }
855 
856 int
857 fdesc_reclaim(void *v)
858 {
859 	struct vop_reclaim_v2_args /* {
860 		struct vnode *a_vp;
861 	} */ *ap = v;
862 	struct vnode *vp = ap->a_vp;
863 	struct fdescnode *fd = VTOFDESC(vp);
864 
865 	VOP_UNLOCK(vp);
866 
867 	vp->v_data = NULL;
868 	kmem_free(fd, sizeof(struct fdescnode));
869 
870 	return (0);
871 }
872 
873 /*
874  * Return POSIX pathconf information applicable to special devices.
875  */
876 int
877 fdesc_pathconf(void *v)
878 {
879 	struct vop_pathconf_args /* {
880 		struct vnode *a_vp;
881 		int a_name;
882 		register_t *a_retval;
883 	} */ *ap = v;
884 
885 	switch (ap->a_name) {
886 	case _PC_LINK_MAX:
887 		*ap->a_retval = LINK_MAX;
888 		return (0);
889 	case _PC_MAX_CANON:
890 		*ap->a_retval = MAX_CANON;
891 		return (0);
892 	case _PC_MAX_INPUT:
893 		*ap->a_retval = MAX_INPUT;
894 		return (0);
895 	case _PC_PIPE_BUF:
896 		*ap->a_retval = PIPE_BUF;
897 		return (0);
898 	case _PC_CHOWN_RESTRICTED:
899 		*ap->a_retval = 1;
900 		return (0);
901 	case _PC_VDISABLE:
902 		*ap->a_retval = _POSIX_VDISABLE;
903 		return (0);
904 	case _PC_SYNC_IO:
905 		*ap->a_retval = 1;
906 		return (0);
907 	default:
908 		return genfs_pathconf(ap);
909 	}
910 	/* NOTREACHED */
911 }
912 
913 /*
914  * Print out the contents of a /dev/fd vnode.
915  */
916 /* ARGSUSED */
917 int
918 fdesc_print(void *v)
919 {
920 	printf("tag VT_NON, fdesc vnode\n");
921 	return (0);
922 }
923 
924 int
925 fdesc_link(void *v)
926 {
927 	struct vop_link_v2_args /* {
928 		struct vnode *a_dvp;
929 		struct vnode *a_vp;
930 		struct componentname *a_cnp;
931 	} */ *ap = v;
932 
933 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
934 	return (EROFS);
935 }
936 
937 int
938 fdesc_symlink(void *v)
939 {
940 	struct vop_symlink_v3_args /* {
941 		struct vnode *a_dvp;
942 		struct vnode **a_vpp;
943 		struct componentname *a_cnp;
944 		struct vattr *a_vap;
945 		char *a_target;
946 	} */ *ap = v;
947 
948 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
949 	return (EROFS);
950 }
951