xref: /netbsd-src/sys/miscfs/fdesc/fdesc_vnops.c (revision 3b01aba77a7a698587faaae455bbfe740923c1f5)
1 /*	$NetBSD: fdesc_vnops.c,v 1.64 2001/06/16 08:28:39 jdolecek 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. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)fdesc_vnops.c	8.17 (Berkeley) 5/22/95
39  *
40  * #Id: fdesc_vnops.c,v 1.12 1993/04/06 16:17:17 jsp Exp #
41  */
42 
43 /*
44  * /dev/fd Filesystem
45  */
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/types.h>
50 #include <sys/time.h>
51 #include <sys/proc.h>
52 #include <sys/kernel.h>	/* boottime */
53 #include <sys/resourcevar.h>
54 #include <sys/socketvar.h>
55 #include <sys/filedesc.h>
56 #include <sys/vnode.h>
57 #include <sys/malloc.h>
58 #include <sys/conf.h>
59 #include <sys/file.h>
60 #include <sys/stat.h>
61 #include <sys/mount.h>
62 #include <sys/namei.h>
63 #include <sys/buf.h>
64 #include <sys/dirent.h>
65 #include <sys/tty.h>
66 
67 #include <miscfs/fdesc/fdesc.h>
68 #include <miscfs/genfs/genfs.h>
69 
70 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
71 
72 #define FDL_WANT	0x01
73 #define FDL_LOCKED	0x02
74 static int fdcache_lock;
75 
76 dev_t devctty;
77 
78 #if (FD_STDIN != FD_STDOUT-1) || (FD_STDOUT != FD_STDERR-1)
79 FD_STDIN, FD_STDOUT, FD_STDERR must be a sequence n, n+1, n+2
80 #endif
81 
82 #define	NFDCACHE 4
83 
84 #define FD_NHASH(ix) \
85 	(&fdhashtbl[(ix) & fdhash])
86 LIST_HEAD(fdhashhead, fdescnode) *fdhashtbl;
87 u_long fdhash;
88 
89 int	fdesc_lookup	__P((void *));
90 #define	fdesc_create	genfs_eopnotsupp_rele
91 #define	fdesc_mknod	genfs_eopnotsupp_rele
92 int	fdesc_open	__P((void *));
93 #define	fdesc_close	genfs_nullop
94 #define	fdesc_access	genfs_nullop
95 int	fdesc_getattr	__P((void *));
96 int	fdesc_setattr	__P((void *));
97 int	fdesc_read	__P((void *));
98 int	fdesc_write	__P((void *));
99 int	fdesc_ioctl	__P((void *));
100 int	fdesc_poll	__P((void *));
101 #define	fdesc_mmap	genfs_eopnotsupp
102 #define	fdesc_fcntl	genfs_fcntl
103 #define	fdesc_fsync	genfs_nullop
104 #define	fdesc_seek	genfs_seek
105 #define	fdesc_remove	genfs_eopnotsupp_rele
106 int	fdesc_link	__P((void *));
107 #define	fdesc_rename	genfs_eopnotsupp_rele
108 #define	fdesc_mkdir	genfs_eopnotsupp_rele
109 #define	fdesc_rmdir	genfs_eopnotsupp_rele
110 int	fdesc_symlink	__P((void *));
111 int	fdesc_readdir	__P((void *));
112 int	fdesc_readlink	__P((void *));
113 #define	fdesc_abortop	genfs_abortop
114 int	fdesc_inactive	__P((void *));
115 int	fdesc_reclaim	__P((void *));
116 #define	fdesc_lock	genfs_lock
117 #define	fdesc_unlock	genfs_unlock
118 #define	fdesc_bmap	genfs_badop
119 #define	fdesc_strategy	genfs_badop
120 int	fdesc_print	__P((void *));
121 int	fdesc_pathconf	__P((void *));
122 #define	fdesc_islocked	genfs_islocked
123 #define	fdesc_advlock	genfs_einval
124 #define	fdesc_blkatoff	genfs_eopnotsupp
125 #define	fdesc_valloc	genfs_eopnotsupp
126 #define	fdesc_vfree	genfs_nullop
127 #define	fdesc_truncate	genfs_eopnotsupp
128 #define	fdesc_update	genfs_nullop
129 #define	fdesc_bwrite	genfs_eopnotsupp
130 #define fdesc_revoke	genfs_revoke
131 
132 static int fdesc_attr __P((int, struct vattr *, struct ucred *, struct proc *));
133 
134 int (**fdesc_vnodeop_p) __P((void *));
135 const struct vnodeopv_entry_desc fdesc_vnodeop_entries[] = {
136 	{ &vop_default_desc, vn_default_error },
137 	{ &vop_lookup_desc, fdesc_lookup },		/* lookup */
138 	{ &vop_create_desc, fdesc_create },		/* create */
139 	{ &vop_mknod_desc, fdesc_mknod },		/* mknod */
140 	{ &vop_open_desc, fdesc_open },			/* open */
141 	{ &vop_close_desc, fdesc_close },		/* close */
142 	{ &vop_access_desc, fdesc_access },		/* access */
143 	{ &vop_getattr_desc, fdesc_getattr },		/* getattr */
144 	{ &vop_setattr_desc, fdesc_setattr },		/* setattr */
145 	{ &vop_read_desc, fdesc_read },			/* read */
146 	{ &vop_write_desc, fdesc_write },		/* write */
147 	{ &vop_ioctl_desc, fdesc_ioctl },		/* ioctl */
148 	{ &vop_fcntl_desc, fdesc_fcntl },		/* fcntl */
149 	{ &vop_poll_desc, fdesc_poll },			/* poll */
150 	{ &vop_revoke_desc, fdesc_revoke },		/* revoke */
151 	{ &vop_mmap_desc, fdesc_mmap },			/* mmap */
152 	{ &vop_fsync_desc, fdesc_fsync },		/* fsync */
153 	{ &vop_seek_desc, fdesc_seek },			/* seek */
154 	{ &vop_remove_desc, fdesc_remove },		/* remove */
155 	{ &vop_link_desc, fdesc_link },			/* link */
156 	{ &vop_rename_desc, fdesc_rename },		/* rename */
157 	{ &vop_mkdir_desc, fdesc_mkdir },		/* mkdir */
158 	{ &vop_rmdir_desc, fdesc_rmdir },		/* rmdir */
159 	{ &vop_symlink_desc, fdesc_symlink },		/* symlink */
160 	{ &vop_readdir_desc, fdesc_readdir },		/* readdir */
161 	{ &vop_readlink_desc, fdesc_readlink },		/* readlink */
162 	{ &vop_abortop_desc, fdesc_abortop },		/* abortop */
163 	{ &vop_inactive_desc, fdesc_inactive },		/* inactive */
164 	{ &vop_reclaim_desc, fdesc_reclaim },		/* reclaim */
165 	{ &vop_lock_desc, fdesc_lock },			/* lock */
166 	{ &vop_unlock_desc, fdesc_unlock },		/* unlock */
167 	{ &vop_bmap_desc, fdesc_bmap },			/* bmap */
168 	{ &vop_strategy_desc, fdesc_strategy },		/* strategy */
169 	{ &vop_print_desc, fdesc_print },		/* print */
170 	{ &vop_islocked_desc, fdesc_islocked },		/* islocked */
171 	{ &vop_pathconf_desc, fdesc_pathconf },		/* pathconf */
172 	{ &vop_advlock_desc, fdesc_advlock },		/* advlock */
173 	{ &vop_blkatoff_desc, fdesc_blkatoff },		/* blkatoff */
174 	{ &vop_valloc_desc, fdesc_valloc },		/* valloc */
175 	{ &vop_vfree_desc, fdesc_vfree },		/* vfree */
176 	{ &vop_truncate_desc, fdesc_truncate },		/* truncate */
177 	{ &vop_update_desc, fdesc_update },		/* update */
178 	{ &vop_bwrite_desc, fdesc_bwrite },		/* bwrite */
179 	{ (struct vnodeop_desc*)NULL, (int(*) __P((void *)))NULL }
180 };
181 
182 const struct vnodeopv_desc fdesc_vnodeop_opv_desc =
183 	{ &fdesc_vnodeop_p, fdesc_vnodeop_entries };
184 
185 /*
186  * Initialise cache headers
187  */
188 void
189 fdesc_init()
190 {
191 	int cttymajor;
192 
193 	/* locate the major number */
194 	for (cttymajor = 0; cttymajor < nchrdev; cttymajor++)
195 		if (cdevsw[cttymajor].d_open == cttyopen)
196 			break;
197 	devctty = makedev(cttymajor, 0);
198 	fdhashtbl = hashinit(NFDCACHE, HASH_LIST, M_CACHE, M_NOWAIT, &fdhash);
199 }
200 
201 /*
202  * Free hash table.
203  */
204 void
205 fdesc_done()
206 {
207 	hashdone(fdhashtbl, M_CACHE);
208 }
209 
210 /*
211  * Return a locked vnode of the correct type.
212  */
213 int
214 fdesc_allocvp(ftype, ix, mp, vpp)
215 	fdntype ftype;
216 	int ix;
217 	struct mount *mp;
218 	struct vnode **vpp;
219 {
220 	struct fdhashhead *fc;
221 	struct fdescnode *fd;
222 	int error = 0;
223 
224 	fc = FD_NHASH(ix);
225 loop:
226 	for (fd = fc->lh_first; fd != 0; fd = fd->fd_hash.le_next) {
227 		if (fd->fd_ix == ix && fd->fd_vnode->v_mount == mp) {
228 			if (vget(fd->fd_vnode, LK_EXCLUSIVE))
229 				goto loop;
230 			*vpp = fd->fd_vnode;
231 			return (error);
232 		}
233 	}
234 
235 	/*
236 	 * otherwise lock the array while we call getnewvnode
237 	 * since that can block.
238 	 */
239 	if (fdcache_lock & FDL_LOCKED) {
240 		fdcache_lock |= FDL_WANT;
241 		(void) tsleep(&fdcache_lock, PINOD, "fdcache", 0);
242 		goto loop;
243 	}
244 	fdcache_lock |= FDL_LOCKED;
245 
246 	error = getnewvnode(VT_FDESC, mp, fdesc_vnodeop_p, vpp);
247 	if (error)
248 		goto out;
249 	MALLOC(fd, void *, sizeof(struct fdescnode), M_TEMP, M_WAITOK);
250 	(*vpp)->v_data = fd;
251 	fd->fd_vnode = *vpp;
252 	fd->fd_type = ftype;
253 	fd->fd_fd = -1;
254 	fd->fd_link = 0;
255 	fd->fd_ix = ix;
256 	VOP_LOCK(*vpp, LK_EXCLUSIVE);
257 	LIST_INSERT_HEAD(fc, fd, fd_hash);
258 
259 out:;
260 	fdcache_lock &= ~FDL_LOCKED;
261 
262 	if (fdcache_lock & FDL_WANT) {
263 		fdcache_lock &= ~FDL_WANT;
264 		wakeup((caddr_t) &fdcache_lock);
265 	}
266 
267 	return (error);
268 }
269 
270 /*
271  * vp is the current namei directory
272  * ndp is the name to locate in that directory...
273  */
274 int
275 fdesc_lookup(v)
276 	void *v;
277 {
278 	struct vop_lookup_args /* {
279 		struct vnode * a_dvp;
280 		struct vnode ** a_vpp;
281 		struct componentname * a_cnp;
282 	} */ *ap = v;
283 	struct vnode **vpp = ap->a_vpp;
284 	struct vnode *dvp = ap->a_dvp;
285 	struct componentname *cnp = ap->a_cnp;
286 	struct proc *p = cnp->cn_proc;
287 	const char *pname = cnp->cn_nameptr;
288 	int nfiles = p->p_fd->fd_nfiles;
289 	unsigned fd = 0;
290 	int error;
291 	struct vnode *fvp;
292 	char *ln;
293 
294 	if (cnp->cn_namelen == 1 && *pname == '.') {
295 		*vpp = dvp;
296 		VREF(dvp);
297 		return (0);
298 	}
299 
300 	switch (VTOFDESC(dvp)->fd_type) {
301 	default:
302 	case Flink:
303 	case Fdesc:
304 	case Fctty:
305 		error = ENOTDIR;
306 		goto bad;
307 
308 	case Froot:
309 		if (cnp->cn_namelen == 2 && memcmp(pname, "fd", 2) == 0) {
310 			error = fdesc_allocvp(Fdevfd, FD_DEVFD, dvp->v_mount, &fvp);
311 			if (error)
312 				goto bad;
313 			*vpp = fvp;
314 			fvp->v_type = VDIR;
315 			goto good;
316 		}
317 
318 		if (cnp->cn_namelen == 3 && memcmp(pname, "tty", 3) == 0) {
319 			struct vnode *ttyvp = cttyvp(p);
320 			if (ttyvp == NULL) {
321 				error = ENXIO;
322 				goto bad;
323 			}
324 			error = fdesc_allocvp(Fctty, FD_CTTY, dvp->v_mount, &fvp);
325 			if (error)
326 				goto bad;
327 			*vpp = fvp;
328 			fvp->v_type = VCHR;
329 			goto good;
330 		}
331 
332 		ln = 0;
333 		switch (cnp->cn_namelen) {
334 		case 5:
335 			if (memcmp(pname, "stdin", 5) == 0) {
336 				ln = "fd/0";
337 				fd = FD_STDIN;
338 			}
339 			break;
340 		case 6:
341 			if (memcmp(pname, "stdout", 6) == 0) {
342 				ln = "fd/1";
343 				fd = FD_STDOUT;
344 			} else
345 			if (memcmp(pname, "stderr", 6) == 0) {
346 				ln = "fd/2";
347 				fd = FD_STDERR;
348 			}
349 			break;
350 		}
351 
352 		if (ln) {
353 			error = fdesc_allocvp(Flink, fd, dvp->v_mount, &fvp);
354 			if (error)
355 				goto bad;
356 			VTOFDESC(fvp)->fd_link = ln;
357 			*vpp = fvp;
358 			fvp->v_type = VLNK;
359 			goto good;
360 		} else {
361 			error = ENOENT;
362 			goto bad;
363 		}
364 
365 		/* FALL THROUGH */
366 
367 	case Fdevfd:
368 		if (cnp->cn_namelen == 2 && memcmp(pname, "..", 2) == 0) {
369 			VOP_UNLOCK(dvp, 0);
370 			cnp->cn_flags |= PDIRUNLOCK;
371 			error = fdesc_root(dvp->v_mount, vpp);
372 			if (error)
373 				goto bad;
374 			/*
375 			 * If we're at the last component and need the
376 			 * parent locked, undo the unlock above.
377 			 */
378 			if (((~cnp->cn_flags & (ISLASTCN | LOCKPARENT)) == 0) &&
379 				   ((error = vn_lock(dvp, LK_EXCLUSIVE)) == 0))
380 				cnp->cn_flags &= ~PDIRUNLOCK;
381 			return (error);
382 		}
383 
384 		fd = 0;
385 		while (*pname >= '0' && *pname <= '9') {
386 			fd = 10 * fd + *pname++ - '0';
387 			if (fd >= nfiles)
388 				break;
389 		}
390 
391 		if (*pname != '\0') {
392 			error = ENOENT;
393 			goto bad;
394 		}
395 
396 		if (fd >= nfiles || p->p_fd->fd_ofiles[fd] == NULL ||
397 		    FILE_IS_USABLE(p->p_fd->fd_ofiles[fd]) == 0) {
398 			error = EBADF;
399 			goto bad;
400 		}
401 
402 		error = fdesc_allocvp(Fdesc, FD_DESC+fd, dvp->v_mount, &fvp);
403 		if (error)
404 			goto bad;
405 		VTOFDESC(fvp)->fd_fd = fd;
406 		*vpp = fvp;
407 		goto good;
408 	}
409 
410 bad:;
411 	*vpp = NULL;
412 	return (error);
413 
414 good:;
415 	/*
416 	 * As "." was special cased above, we now unlock the parent if we're
417 	 * suppoed to. We're only supposed to not unlock if this is the
418 	 * last component, and the caller requested LOCKPARENT. So if either
419 	 * condition is false, unlock.
420 	 */
421 	if (((~cnp->cn_flags) & (ISLASTCN | LOCKPARENT)) != 0) {
422 		VOP_UNLOCK(dvp, 0);
423 		cnp->cn_flags |= PDIRUNLOCK;
424 	}
425 	return (0);
426 }
427 
428 int
429 fdesc_open(v)
430 	void *v;
431 {
432 	struct vop_open_args /* {
433 		struct vnode *a_vp;
434 		int  a_mode;
435 		struct ucred *a_cred;
436 		struct proc *a_p;
437 	} */ *ap = v;
438 	struct vnode *vp = ap->a_vp;
439 
440 	switch (VTOFDESC(vp)->fd_type) {
441 	case Fdesc:
442 		/*
443 		 * XXX Kludge: set p->p_dupfd to contain the value of the
444 		 * the file descriptor being sought for duplication. The error
445 		 * return ensures that the vnode for this device will be
446 		 * released by vn_open. Open will detect this special error and
447 		 * take the actions in dupfdopen.  Other callers of vn_open or
448 		 * VOP_OPEN will simply report the error.
449 		 */
450 		ap->a_p->p_dupfd = VTOFDESC(vp)->fd_fd;	/* XXX */
451 		return (ENODEV);
452 
453 	case Fctty:
454 		return (cttyopen(devctty, ap->a_mode, 0, ap->a_p));
455 	case Froot:
456 	case Fdevfd:
457 	case Flink:
458 		break;
459 	}
460 
461 	return (0);
462 }
463 
464 static int
465 fdesc_attr(fd, vap, cred, p)
466 	int fd;
467 	struct vattr *vap;
468 	struct ucred *cred;
469 	struct proc *p;
470 {
471 	struct filedesc *fdp = p->p_fd;
472 	struct file *fp;
473 	struct stat stb;
474 	int error;
475 
476 	if ((fp = fd_getfile(fdp, fd)) == NULL)
477 		return (EBADF);
478 
479 	switch (fp->f_type) {
480 	case DTYPE_VNODE:
481 		error = VOP_GETATTR((struct vnode *) fp->f_data, vap, cred, p);
482 		if (error == 0 && vap->va_type == VDIR) {
483 			/*
484 			 * directories can cause loops in the namespace,
485 			 * so turn off the 'x' bits to avoid trouble.
486 			 */
487 			vap->va_mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
488 		}
489 		break;
490 
491 	case DTYPE_SOCKET:
492 	case DTYPE_PIPE:
493 		FILE_USE(fp);
494 		error = (*fp->f_ops->fo_stat)(fp, &stb, p);
495 		FILE_UNUSE(fp, p);
496 		if (error == 0) {
497 			vattr_null(vap);
498 			if (fp->f_type == DTYPE_SOCKET)
499 				vap->va_type = VSOCK;
500 			else
501 				vap->va_type = VFIFO;
502 			vap->va_mode = stb.st_mode;
503 			vap->va_nlink = stb.st_nlink;
504 			vap->va_uid = stb.st_uid;
505 			vap->va_gid = stb.st_gid;
506 			vap->va_fsid = stb.st_dev;
507 			vap->va_fileid = stb.st_ino;
508 			vap->va_size = stb.st_size;
509 			vap->va_blocksize = stb.st_blksize;
510 			vap->va_atime = stb.st_atimespec;
511 			vap->va_mtime = stb.st_mtimespec;
512 			vap->va_ctime = stb.st_ctimespec;
513 			vap->va_gen = stb.st_gen;
514 			vap->va_flags = stb.st_flags;
515 			vap->va_rdev = stb.st_rdev;
516 			vap->va_bytes = stb.st_blocks * stb.st_blksize;
517 		}
518 		break;
519 
520 	default:
521 		panic("fdesc attr");
522 		break;
523 	}
524 
525 	return (error);
526 }
527 
528 int
529 fdesc_getattr(v)
530 	void *v;
531 {
532 	struct vop_getattr_args /* {
533 		struct vnode *a_vp;
534 		struct vattr *a_vap;
535 		struct ucred *a_cred;
536 		struct proc *a_p;
537 	} */ *ap = v;
538 	struct vnode *vp = ap->a_vp;
539 	struct vattr *vap = ap->a_vap;
540 	unsigned fd;
541 	int error = 0;
542 
543 	switch (VTOFDESC(vp)->fd_type) {
544 	case Froot:
545 	case Fdevfd:
546 	case Flink:
547 	case Fctty:
548 		VATTR_NULL(vap);
549 		vap->va_fileid = VTOFDESC(vp)->fd_ix;
550 
551 #define R_ALL (S_IRUSR|S_IRGRP|S_IROTH)
552 #define W_ALL (S_IWUSR|S_IWGRP|S_IWOTH)
553 #define X_ALL (S_IXUSR|S_IXGRP|S_IXOTH)
554 
555 		switch (VTOFDESC(vp)->fd_type) {
556 		case Flink:
557 			vap->va_mode = R_ALL|X_ALL;
558 			vap->va_type = VLNK;
559 			vap->va_rdev = 0;
560 			vap->va_nlink = 1;
561 			vap->va_size = strlen(VTOFDESC(vp)->fd_link);
562 			break;
563 
564 		case Fctty:
565 			vap->va_mode = R_ALL|W_ALL;
566 			vap->va_type = VCHR;
567 			vap->va_rdev = devctty;
568 			vap->va_nlink = 1;
569 			vap->va_size = 0;
570 			break;
571 
572 		default:
573 			vap->va_mode = R_ALL|X_ALL;
574 			vap->va_type = VDIR;
575 			vap->va_rdev = 0;
576 			vap->va_nlink = 2;
577 			vap->va_size = DEV_BSIZE;
578 			break;
579 		}
580 		vap->va_uid = 0;
581 		vap->va_gid = 0;
582 		vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
583 		vap->va_blocksize = DEV_BSIZE;
584 		vap->va_atime.tv_sec = boottime.tv_sec;
585 		vap->va_atime.tv_nsec = 0;
586 		vap->va_mtime = vap->va_atime;
587 		vap->va_ctime = vap->va_mtime;
588 		vap->va_gen = 0;
589 		vap->va_flags = 0;
590 		vap->va_bytes = 0;
591 		break;
592 
593 	case Fdesc:
594 		fd = VTOFDESC(vp)->fd_fd;
595 		error = fdesc_attr(fd, vap, ap->a_cred, ap->a_p);
596 		break;
597 
598 	default:
599 		panic("fdesc_getattr");
600 		break;
601 	}
602 
603 	if (error == 0)
604 		vp->v_type = vap->va_type;
605 
606 	return (error);
607 }
608 
609 int
610 fdesc_setattr(v)
611 	void *v;
612 {
613 	struct vop_setattr_args /* {
614 		struct vnode *a_vp;
615 		struct vattr *a_vap;
616 		struct ucred *a_cred;
617 		struct proc *a_p;
618 	} */ *ap = v;
619 	struct filedesc *fdp = ap->a_p->p_fd;
620 	struct file *fp;
621 	unsigned fd;
622 	int error;
623 
624 	/*
625 	 * Can't mess with the root vnode
626 	 */
627 	switch (VTOFDESC(ap->a_vp)->fd_type) {
628 	case Fdesc:
629 		break;
630 
631 	case Fctty:
632 		return (0);
633 
634 	default:
635 		return (EACCES);
636 	}
637 
638 	fd = VTOFDESC(ap->a_vp)->fd_fd;
639 	if ((fp = fd_getfile(fdp, fd)) == NULL)
640 		return (EBADF);
641 
642 	/*
643 	 * Can setattr the underlying vnode, but not sockets!
644 	 */
645 	switch (fp->f_type) {
646 	case DTYPE_VNODE:
647 	case DTYPE_SOCKET:
648 		error = 0;
649 		break;
650 
651 	default:
652 		panic("fdesc setattr");
653 		break;
654 	}
655 
656 	return (error);
657 }
658 
659 #define UIO_MX 32
660 
661 struct fdesc_target {
662 	ino_t ft_fileno;
663 	u_char ft_type;
664 	u_char ft_namlen;
665 	char *ft_name;
666 } fdesc_targets[] = {
667 /* NOTE: The name must be less than UIO_MX-16 chars in length */
668 #define N(s) sizeof(s)-1, s
669 	{ FD_DEVFD,  DT_DIR,     N("fd")     },
670 	{ FD_STDIN,  DT_LNK,     N("stdin")  },
671 	{ FD_STDOUT, DT_LNK,     N("stdout") },
672 	{ FD_STDERR, DT_LNK,     N("stderr") },
673 	{ FD_CTTY,   DT_UNKNOWN, N("tty")    },
674 #undef N
675 };
676 static int nfdesc_targets = sizeof(fdesc_targets) / sizeof(fdesc_targets[0]);
677 
678 int
679 fdesc_readdir(v)
680 	void *v;
681 {
682 	struct vop_readdir_args /* {
683 		struct vnode *a_vp;
684 		struct uio *a_uio;
685 		struct ucred *a_cred;
686 		int *a_eofflag;
687 		off_t **a_cookies;
688 		int *a_ncookies;
689 	} */ *ap = v;
690 	struct uio *uio = ap->a_uio;
691 	struct dirent d;
692 	struct filedesc *fdp;
693 	off_t i;
694 	int error;
695 	off_t *cookies = NULL;
696 	int ncookies = 0;
697 
698 	switch (VTOFDESC(ap->a_vp)->fd_type) {
699 	case Fctty:
700 		return (0);
701 
702 	case Fdesc:
703 		return (ENOTDIR);
704 
705 	default:
706 		break;
707 	}
708 
709 	fdp = uio->uio_procp->p_fd;
710 
711 	if (uio->uio_resid < UIO_MX)
712 		return (EINVAL);
713 	if (uio->uio_offset < 0)
714 		return (EINVAL);
715 
716 	error = 0;
717 	i = uio->uio_offset;
718 	memset((caddr_t)&d, 0, UIO_MX);
719 	d.d_reclen = UIO_MX;
720 	if (ap->a_ncookies)
721 		ncookies = (uio->uio_resid / UIO_MX);
722 
723 	if (VTOFDESC(ap->a_vp)->fd_type == Froot) {
724 		struct fdesc_target *ft;
725 
726 		if (i >= nfdesc_targets)
727 			return 0;
728 
729 		if (ap->a_ncookies) {
730 			ncookies = min(ncookies, (nfdesc_targets - i));
731 			cookies = malloc(ncookies * sizeof(off_t),
732 			    M_TEMP, M_WAITOK);
733 			*ap->a_cookies = cookies;
734 			*ap->a_ncookies = ncookies;
735 		}
736 
737 		for (ft = &fdesc_targets[i];
738 		     uio->uio_resid >= UIO_MX && i < nfdesc_targets; ft++, i++) {
739 			switch (ft->ft_fileno) {
740 			case FD_CTTY:
741 				if (cttyvp(uio->uio_procp) == NULL)
742 					continue;
743 				break;
744 
745 			case FD_STDIN:
746 			case FD_STDOUT:
747 			case FD_STDERR:
748 				if ((ft->ft_fileno - FD_STDIN) >= fdp->fd_nfiles)
749 					continue;
750 				if (fdp->fd_ofiles[ft->ft_fileno - FD_STDIN] == NULL
751 				    || FILE_IS_USABLE(fdp->fd_ofiles[ft->ft_fileno - FD_STDIN]) == 0)
752 					continue;
753 				break;
754 			}
755 
756 			d.d_fileno = ft->ft_fileno;
757 			d.d_namlen = ft->ft_namlen;
758 			memcpy(d.d_name, ft->ft_name, ft->ft_namlen + 1);
759 			d.d_type = ft->ft_type;
760 
761 			if ((error = uiomove((caddr_t)&d, UIO_MX, uio)) != 0)
762 				break;
763 			if (cookies)
764 				*cookies++ = i + 1;
765 		}
766 	} else {
767 		if (ap->a_ncookies) {
768 			ncookies = min(ncookies, (fdp->fd_nfiles + 2));
769 			cookies = malloc(ncookies * sizeof(off_t),
770 			    M_TEMP, M_WAITOK);
771 			*ap->a_cookies = cookies;
772 			*ap->a_ncookies = ncookies;
773 		}
774 		for (; i - 2 < fdp->fd_nfiles && uio->uio_resid >= UIO_MX;
775 		     i++) {
776 			switch (i) {
777 			case 0:
778 			case 1:
779 				d.d_fileno = FD_ROOT;		/* XXX */
780 				d.d_namlen = i + 1;
781 				memcpy(d.d_name, "..", d.d_namlen);
782 				d.d_name[i + 1] = '\0';
783 				d.d_type = DT_DIR;
784 				break;
785 
786 			default:
787 				if (fdp->fd_ofiles[i - 2] == NULL ||
788 				    FILE_IS_USABLE(fdp->fd_ofiles[i - 2]) == 0)
789 					continue;
790 				d.d_fileno = i - 2 + FD_STDIN;
791 				d.d_namlen = sprintf(d.d_name, "%d", (int) i - 2);
792 				d.d_type = DT_UNKNOWN;
793 				break;
794 			}
795 
796 			if ((error = uiomove((caddr_t)&d, UIO_MX, uio)) != 0)
797 				break;
798 			if (cookies)
799 				*cookies++ = i + 1;
800 		}
801 	}
802 
803 	if (ap->a_ncookies && error) {
804 		free(*ap->a_cookies, M_TEMP);
805 		*ap->a_ncookies = 0;
806 		*ap->a_cookies = NULL;
807 	}
808 
809 	uio->uio_offset = i;
810 	return (error);
811 }
812 
813 int
814 fdesc_readlink(v)
815 	void *v;
816 {
817 	struct vop_readlink_args /* {
818 		struct vnode *a_vp;
819 		struct uio *a_uio;
820 		struct ucred *a_cred;
821 	} */ *ap = v;
822 	struct vnode *vp = ap->a_vp;
823 	int error;
824 
825 	if (vp->v_type != VLNK)
826 		return (EPERM);
827 
828 	if (VTOFDESC(vp)->fd_type == Flink) {
829 		char *ln = VTOFDESC(vp)->fd_link;
830 		error = uiomove(ln, strlen(ln), ap->a_uio);
831 	} else {
832 		error = EOPNOTSUPP;
833 	}
834 
835 	return (error);
836 }
837 
838 int
839 fdesc_read(v)
840 	void *v;
841 {
842 	struct vop_read_args /* {
843 		struct vnode *a_vp;
844 		struct uio *a_uio;
845 		int  a_ioflag;
846 		struct ucred *a_cred;
847 	} */ *ap = v;
848 	int error = EOPNOTSUPP;
849 	struct vnode *vp = ap->a_vp;
850 
851 	switch (VTOFDESC(vp)->fd_type) {
852 	case Fctty:
853 		VOP_UNLOCK(vp, 0);
854 		error = cttyread(devctty, ap->a_uio, ap->a_ioflag);
855 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
856 		break;
857 
858 	default:
859 		error = EOPNOTSUPP;
860 		break;
861 	}
862 
863 	return (error);
864 }
865 
866 int
867 fdesc_write(v)
868 	void *v;
869 {
870 	struct vop_write_args /* {
871 		struct vnode *a_vp;
872 		struct uio *a_uio;
873 		int  a_ioflag;
874 		struct ucred *a_cred;
875 	} */ *ap = v;
876 	int error = EOPNOTSUPP;
877 	struct vnode *vp = ap->a_vp;
878 
879 	switch (VTOFDESC(vp)->fd_type) {
880 	case Fctty:
881 		VOP_UNLOCK(vp, 0);
882 		error = cttywrite(devctty, ap->a_uio, ap->a_ioflag);
883 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
884 		break;
885 
886 	default:
887 		error = EOPNOTSUPP;
888 		break;
889 	}
890 
891 	return (error);
892 }
893 
894 int
895 fdesc_ioctl(v)
896 	void *v;
897 {
898 	struct vop_ioctl_args /* {
899 		struct vnode *a_vp;
900 		u_long a_command;
901 		caddr_t  a_data;
902 		int  a_fflag;
903 		struct ucred *a_cred;
904 		struct proc *a_p;
905 	} */ *ap = v;
906 	int error = EOPNOTSUPP;
907 
908 	switch (VTOFDESC(ap->a_vp)->fd_type) {
909 	case Fctty:
910 		error = cttyioctl(devctty, ap->a_command, ap->a_data,
911 				  ap->a_fflag, ap->a_p);
912 		break;
913 
914 	default:
915 		error = EOPNOTSUPP;
916 		break;
917 	}
918 
919 	return (error);
920 }
921 
922 int
923 fdesc_poll(v)
924 	void *v;
925 {
926 	struct vop_poll_args /* {
927 		struct vnode *a_vp;
928 		int a_events;
929 		struct proc *a_p;
930 	} */ *ap = v;
931 	int revents;
932 
933 	switch (VTOFDESC(ap->a_vp)->fd_type) {
934 	case Fctty:
935 		revents = cttypoll(devctty, ap->a_events, ap->a_p);
936 		break;
937 
938 	default:
939 		revents = genfs_poll(v);
940 		break;
941 	}
942 
943 	return (revents);
944 }
945 
946 int
947 fdesc_inactive(v)
948 	void *v;
949 {
950 	struct vop_inactive_args /* {
951 		struct vnode *a_vp;
952 		struct proc *a_p;
953 	} */ *ap = v;
954 	struct vnode *vp = ap->a_vp;
955 
956 	/*
957 	 * Clear out the v_type field to avoid
958 	 * nasty things happening in vgone().
959 	 */
960 	VOP_UNLOCK(vp, 0);
961 	vp->v_type = VNON;
962 	return (0);
963 }
964 
965 int
966 fdesc_reclaim(v)
967 	void *v;
968 {
969 	struct vop_reclaim_args /* {
970 		struct vnode *a_vp;
971 	} */ *ap = v;
972 	struct vnode *vp = ap->a_vp;
973 	struct fdescnode *fd = VTOFDESC(vp);
974 
975 	LIST_REMOVE(fd, fd_hash);
976 	FREE(vp->v_data, M_TEMP);
977 	vp->v_data = 0;
978 
979 	return (0);
980 }
981 
982 /*
983  * Return POSIX pathconf information applicable to special devices.
984  */
985 int
986 fdesc_pathconf(v)
987 	void *v;
988 {
989 	struct vop_pathconf_args /* {
990 		struct vnode *a_vp;
991 		int a_name;
992 		register_t *a_retval;
993 	} */ *ap = v;
994 
995 	switch (ap->a_name) {
996 	case _PC_LINK_MAX:
997 		*ap->a_retval = LINK_MAX;
998 		return (0);
999 	case _PC_MAX_CANON:
1000 		*ap->a_retval = MAX_CANON;
1001 		return (0);
1002 	case _PC_MAX_INPUT:
1003 		*ap->a_retval = MAX_INPUT;
1004 		return (0);
1005 	case _PC_PIPE_BUF:
1006 		*ap->a_retval = PIPE_BUF;
1007 		return (0);
1008 	case _PC_CHOWN_RESTRICTED:
1009 		*ap->a_retval = 1;
1010 		return (0);
1011 	case _PC_VDISABLE:
1012 		*ap->a_retval = _POSIX_VDISABLE;
1013 		return (0);
1014 	case _PC_SYNC_IO:
1015 		*ap->a_retval = 1;
1016 		return (0);
1017 	default:
1018 		return (EINVAL);
1019 	}
1020 	/* NOTREACHED */
1021 }
1022 
1023 /*
1024  * Print out the contents of a /dev/fd vnode.
1025  */
1026 /* ARGSUSED */
1027 int
1028 fdesc_print(v)
1029 	void *v;
1030 {
1031 	printf("tag VT_NON, fdesc vnode\n");
1032 	return (0);
1033 }
1034 
1035 int
1036 fdesc_link(v)
1037 	void *v;
1038 {
1039 	struct vop_link_args /* {
1040 		struct vnode *a_dvp;
1041 		struct vnode *a_vp;
1042 		struct componentname *a_cnp;
1043 	} */ *ap = v;
1044 
1045 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
1046 	vput(ap->a_dvp);
1047 	return (EROFS);
1048 }
1049 
1050 int
1051 fdesc_symlink(v)
1052 	void *v;
1053 {
1054 	struct vop_symlink_args /* {
1055 		struct vnode *a_dvp;
1056 		struct vnode **a_vpp;
1057 		struct componentname *a_cnp;
1058 		struct vattr *a_vap;
1059 		char *a_target;
1060 	} */ *ap = v;
1061 
1062 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
1063 	vput(ap->a_dvp);
1064 	return (EROFS);
1065 }
1066