xref: /netbsd-src/sys/fs/ptyfs/ptyfs_vnops.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06)
1 /*	$NetBSD: ptyfs_vnops.c,v 1.12 2005/12/11 12:24:29 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1993, 1995
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed 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  *	@(#)procfs_vnops.c	8.18 (Berkeley) 5/21/95
35  */
36 
37 /*
38  * Copyright (c) 1993 Jan-Simon Pendry
39  *
40  * This code is derived from software contributed to Berkeley by
41  * Jan-Simon Pendry.
42  *
43  * Redistribution and use in source and binary forms, with or without
44  * modification, are permitted provided that the following conditions
45  * are met:
46  * 1. Redistributions of source code must retain the above copyright
47  *    notice, this list of conditions and the following disclaimer.
48  * 2. Redistributions in binary form must reproduce the above copyright
49  *    notice, this list of conditions and the following disclaimer in the
50  *    documentation and/or other materials provided with the distribution.
51  * 3. All advertising materials mentioning features or use of this software
52  *    must display the following acknowledgement:
53  *	This product includes software developed by the University of
54  *	California, Berkeley and its contributors.
55  * 4. Neither the name of the University nor the names of its contributors
56  *    may be used to endorse or promote products derived from this software
57  *    without specific prior written permission.
58  *
59  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
60  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
61  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
62  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
63  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
64  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
65  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
66  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
67  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
68  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
69  * SUCH DAMAGE.
70  *
71  *	@(#)procfs_vnops.c	8.18 (Berkeley) 5/21/95
72  */
73 
74 /*
75  * ptyfs vnode interface
76  */
77 
78 #include <sys/cdefs.h>
79 __KERNEL_RCSID(0, "$NetBSD: ptyfs_vnops.c,v 1.12 2005/12/11 12:24:29 christos Exp $");
80 
81 #include <sys/param.h>
82 #include <sys/systm.h>
83 #include <sys/time.h>
84 #include <sys/kernel.h>
85 #include <sys/file.h>
86 #include <sys/filedesc.h>
87 #include <sys/proc.h>
88 #include <sys/vnode.h>
89 #include <sys/namei.h>
90 #include <sys/malloc.h>
91 #include <sys/mount.h>
92 #include <sys/select.h>
93 #include <sys/dirent.h>
94 #include <sys/resourcevar.h>
95 #include <sys/stat.h>
96 #include <sys/conf.h>
97 #include <sys/tty.h>
98 #include <sys/pty.h>
99 
100 #include <uvm/uvm_extern.h>	/* for PAGE_SIZE */
101 
102 #include <machine/reg.h>
103 
104 #include <fs/ptyfs/ptyfs.h>
105 #include <miscfs/genfs/genfs.h>
106 #include <miscfs/specfs/specdev.h>
107 
108 /*
109  * Vnode Operations.
110  *
111  */
112 
113 int	ptyfs_lookup	(void *);
114 #define	ptyfs_create	genfs_eopnotsupp
115 #define	ptyfs_mknod	genfs_eopnotsupp
116 int	ptyfs_open	(void *);
117 int	ptyfs_close	(void *);
118 int	ptyfs_access	(void *);
119 int	ptyfs_getattr	(void *);
120 int	ptyfs_setattr	(void *);
121 int	ptyfs_read	(void *);
122 int	ptyfs_write	(void *);
123 #define	ptyfs_fcntl	genfs_fcntl
124 int	ptyfs_ioctl	(void *);
125 int	ptyfs_poll	(void *);
126 int	ptyfs_kqfilter	(void *);
127 #define ptyfs_revoke	genfs_revoke
128 #define	ptyfs_mmap	genfs_eopnotsupp
129 #define	ptyfs_fsync	genfs_nullop
130 #define	ptyfs_seek	genfs_nullop
131 #define	ptyfs_remove	genfs_eopnotsupp
132 #define	ptyfs_link	genfs_abortop
133 #define	ptyfs_rename	genfs_eopnotsupp
134 #define	ptyfs_mkdir	genfs_eopnotsupp
135 #define	ptyfs_rmdir	genfs_eopnotsupp
136 #define	ptyfs_symlink	genfs_abortop
137 int	ptyfs_readdir	(void *);
138 #define	ptyfs_readlink	genfs_eopnotsupp
139 #define	ptyfs_abortop	genfs_abortop
140 int	ptyfs_reclaim	(void *);
141 #define	ptyfs_lock	genfs_lock
142 #define	ptyfs_unlock	genfs_unlock
143 #define	ptyfs_bmap	genfs_badop
144 #define	ptyfs_strategy	genfs_badop
145 int	ptyfs_print	(void *);
146 int	ptyfs_pathconf	(void *);
147 #define	ptyfs_islocked	genfs_islocked
148 #define	ptyfs_advlock	genfs_einval
149 #define	ptyfs_bwrite	genfs_eopnotsupp
150 #define ptyfs_putpages	genfs_null_putpages
151 
152 static int ptyfs_update(struct vnode *, const struct timespec *,
153     const struct timespec *, int);
154 static int ptyfs_chown(struct vnode *, uid_t, gid_t, struct ucred *,
155     struct proc *);
156 static int ptyfs_chmod(struct vnode *, mode_t, struct ucred *, struct proc *);
157 static int atoi(const char *, size_t);
158 
159 extern const struct cdevsw pts_cdevsw, ptc_cdevsw;
160 
161 /*
162  * ptyfs vnode operations.
163  */
164 int (**ptyfs_vnodeop_p)(void *);
165 const struct vnodeopv_entry_desc ptyfs_vnodeop_entries[] = {
166 	{ &vop_default_desc, vn_default_error },
167 	{ &vop_lookup_desc, ptyfs_lookup },		/* lookup */
168 	{ &vop_create_desc, ptyfs_create },		/* create */
169 	{ &vop_mknod_desc, ptyfs_mknod },		/* mknod */
170 	{ &vop_open_desc, ptyfs_open },			/* open */
171 	{ &vop_close_desc, ptyfs_close },		/* close */
172 	{ &vop_access_desc, ptyfs_access },		/* access */
173 	{ &vop_getattr_desc, ptyfs_getattr },		/* getattr */
174 	{ &vop_setattr_desc, ptyfs_setattr },		/* setattr */
175 	{ &vop_read_desc, ptyfs_read },			/* read */
176 	{ &vop_write_desc, ptyfs_write },		/* write */
177 	{ &vop_ioctl_desc, ptyfs_ioctl },		/* ioctl */
178 	{ &vop_fcntl_desc, ptyfs_fcntl },		/* fcntl */
179 	{ &vop_poll_desc, ptyfs_poll },			/* poll */
180 	{ &vop_kqfilter_desc, ptyfs_kqfilter },		/* kqfilter */
181 	{ &vop_revoke_desc, ptyfs_revoke },		/* revoke */
182 	{ &vop_mmap_desc, ptyfs_mmap },			/* mmap */
183 	{ &vop_fsync_desc, ptyfs_fsync },		/* fsync */
184 	{ &vop_seek_desc, ptyfs_seek },			/* seek */
185 	{ &vop_remove_desc, ptyfs_remove },		/* remove */
186 	{ &vop_link_desc, ptyfs_link },			/* link */
187 	{ &vop_rename_desc, ptyfs_rename },		/* rename */
188 	{ &vop_mkdir_desc, ptyfs_mkdir },		/* mkdir */
189 	{ &vop_rmdir_desc, ptyfs_rmdir },		/* rmdir */
190 	{ &vop_symlink_desc, ptyfs_symlink },		/* symlink */
191 	{ &vop_readdir_desc, ptyfs_readdir },		/* readdir */
192 	{ &vop_readlink_desc, ptyfs_readlink },		/* readlink */
193 	{ &vop_abortop_desc, ptyfs_abortop },		/* abortop */
194 	{ &vop_inactive_desc, spec_inactive },		/* inactive */
195 	{ &vop_reclaim_desc, ptyfs_reclaim },		/* reclaim */
196 	{ &vop_lock_desc, ptyfs_lock },			/* lock */
197 	{ &vop_unlock_desc, ptyfs_unlock },		/* unlock */
198 	{ &vop_bmap_desc, ptyfs_bmap },			/* bmap */
199 	{ &vop_strategy_desc, ptyfs_strategy },		/* strategy */
200 	{ &vop_print_desc, ptyfs_print },		/* print */
201 	{ &vop_islocked_desc, ptyfs_islocked },		/* islocked */
202 	{ &vop_pathconf_desc, ptyfs_pathconf },		/* pathconf */
203 	{ &vop_advlock_desc, ptyfs_advlock },		/* advlock */
204 	{ &vop_bwrite_desc, ptyfs_bwrite },		/* bwrite */
205 	{ &vop_putpages_desc, ptyfs_putpages },		/* putpages */
206 	{ NULL, NULL }
207 };
208 const struct vnodeopv_desc ptyfs_vnodeop_opv_desc =
209 	{ &ptyfs_vnodeop_p, ptyfs_vnodeop_entries };
210 
211 /*
212  * _reclaim is called when getnewvnode()
213  * wants to make use of an entry on the vnode
214  * free list.  at this time the filesystem needs
215  * to free any private data and remove the node
216  * from any private lists.
217  */
218 int
219 ptyfs_reclaim(void *v)
220 {
221 	struct vop_reclaim_args /* {
222 		struct vnode *a_vp;
223 	} */ *ap = v;
224 	return ptyfs_freevp(ap->a_vp);
225 }
226 
227 /*
228  * Return POSIX pathconf information applicable to special devices.
229  */
230 int
231 ptyfs_pathconf(void *v)
232 {
233 	struct vop_pathconf_args /* {
234 		struct vnode *a_vp;
235 		int a_name;
236 		register_t *a_retval;
237 	} */ *ap = v;
238 
239 	switch (ap->a_name) {
240 	case _PC_LINK_MAX:
241 		*ap->a_retval = LINK_MAX;
242 		return 0;
243 	case _PC_MAX_CANON:
244 		*ap->a_retval = MAX_CANON;
245 		return 0;
246 	case _PC_MAX_INPUT:
247 		*ap->a_retval = MAX_INPUT;
248 		return 0;
249 	case _PC_PIPE_BUF:
250 		*ap->a_retval = PIPE_BUF;
251 		return 0;
252 	case _PC_CHOWN_RESTRICTED:
253 		*ap->a_retval = 1;
254 		return 0;
255 	case _PC_VDISABLE:
256 		*ap->a_retval = _POSIX_VDISABLE;
257 		return 0;
258 	case _PC_SYNC_IO:
259 		*ap->a_retval = 1;
260 		return 0;
261 	default:
262 		return EINVAL;
263 	}
264 }
265 
266 /*
267  * _print is used for debugging.
268  * just print a readable description
269  * of (vp).
270  */
271 int
272 ptyfs_print(void *v)
273 {
274 	struct vop_print_args /* {
275 		struct vnode *a_vp;
276 	} */ *ap = v;
277 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
278 
279 	printf("tag VT_PTYFS, type %d, pty %d\n",
280 	    ptyfs->ptyfs_type, ptyfs->ptyfs_pty);
281 	return 0;
282 }
283 
284 /*
285  * Invent attributes for ptyfsnode (vp) and store
286  * them in (vap).
287  * Directories lengths are returned as zero since
288  * any real length would require the genuine size
289  * to be computed, and nothing cares anyway.
290  *
291  * this is relatively minimal for ptyfs.
292  */
293 int
294 ptyfs_getattr(void *v)
295 {
296 	struct vop_getattr_args /* {
297 		struct vnode *a_vp;
298 		struct vattr *a_vap;
299 		struct ucred *a_cred;
300 		struct lwp *a_l;
301 	} */ *ap = v;
302 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
303 	struct vattr *vap = ap->a_vap;
304 
305 	PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
306 
307 	/* start by zeroing out the attributes */
308 	VATTR_NULL(vap);
309 
310 	/* next do all the common fields */
311 	vap->va_type = ap->a_vp->v_type;
312 	vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0];
313 	vap->va_fileid = ptyfs->ptyfs_fileno;
314 	vap->va_gen = 0;
315 	vap->va_flags = 0;
316 	vap->va_nlink = 1;
317 	vap->va_blocksize = PAGE_SIZE;
318 
319 	vap->va_atime = ptyfs->ptyfs_atime;
320 	vap->va_mtime = ptyfs->ptyfs_mtime;
321 	vap->va_ctime = ptyfs->ptyfs_ctime;
322 	vap->va_birthtime = ptyfs->ptyfs_birthtime;
323 	vap->va_mode = ptyfs->ptyfs_mode;
324 	vap->va_flags = ptyfs->ptyfs_flags;
325 	vap->va_uid = ptyfs->ptyfs_uid;
326 	vap->va_gid = ptyfs->ptyfs_gid;
327 
328 	switch (ptyfs->ptyfs_type) {
329 	case PTYFSpts:
330 	case PTYFSptc:
331 		if (pty_isfree(ptyfs->ptyfs_pty, 1))
332 			return ENOENT;
333 		vap->va_bytes = vap->va_size = 0;
334 		vap->va_rdev = ap->a_vp->v_rdev;
335 		break;
336 	case PTYFSroot:
337 		vap->va_rdev = 0;
338 		vap->va_bytes = vap->va_size = DEV_BSIZE;
339 		break;
340 
341 	default:
342 		return EOPNOTSUPP;
343 	}
344 
345 	return 0;
346 }
347 
348 /*ARGSUSED*/
349 int
350 ptyfs_setattr(void *v)
351 {
352 	struct vop_setattr_args /* {
353 		struct vnodeop_desc *a_desc;
354 		struct vnode *a_vp;
355 		struct vattr *a_vap;
356 		struct ucred *a_cred;
357 		struct lwp *a_l;
358 	} */ *ap = v;
359 	struct vnode *vp = ap->a_vp;
360 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
361 	struct vattr *vap = ap->a_vap;
362 	struct ucred *cred = ap->a_cred;
363 	struct lwp *l = ap->a_l;
364 	struct proc *p = l->l_proc;
365 	int error;
366 
367 	if (vap->va_size != VNOVAL) {
368  		switch (ptyfs->ptyfs_type) {
369  		case PTYFSroot:
370  			return EISDIR;
371  		case PTYFSpts:
372  		case PTYFSptc:
373 			break;
374 		default:
375 			return EINVAL;
376 		}
377 	}
378 
379 	if (vap->va_flags != VNOVAL) {
380 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
381 			return EROFS;
382 		if (cred->cr_uid != ptyfs->ptyfs_uid &&
383 		    (error = suser(cred, &p->p_acflag)) != 0)
384 			return error;
385 		if (cred->cr_uid == 0) {
386 			if ((ptyfs->ptyfs_flags & (SF_IMMUTABLE | SF_APPEND)) &&
387 			    securelevel > 0)
388 				return EPERM;
389 			/* Snapshot flag cannot be set or cleared */
390 			if ((vap->va_flags & SF_SNAPSHOT) !=
391 			    (ptyfs->ptyfs_flags & SF_SNAPSHOT))
392 				return EPERM;
393 			ptyfs->ptyfs_flags = vap->va_flags;
394 		} else {
395 			if ((ptyfs->ptyfs_flags & (SF_IMMUTABLE | SF_APPEND)) ||
396 			    (vap->va_flags & UF_SETTABLE) != vap->va_flags)
397 				return EPERM;
398 			if ((ptyfs->ptyfs_flags & SF_SETTABLE) !=
399 			    (vap->va_flags & SF_SETTABLE))
400 				return EPERM;
401 			ptyfs->ptyfs_flags &= SF_SETTABLE;
402 			ptyfs->ptyfs_flags |= (vap->va_flags & UF_SETTABLE);
403 		}
404 		ptyfs->ptyfs_flag |= PTYFS_CHANGE;
405 		if (vap->va_flags & (IMMUTABLE | APPEND))
406 			return 0;
407 	}
408 	if (ptyfs->ptyfs_flags & (IMMUTABLE | APPEND))
409 		return EPERM;
410 	/*
411 	 * Go through the fields and update iff not VNOVAL.
412 	 */
413 	if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
414 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
415 			return EROFS;
416 		if (ptyfs->ptyfs_type == PTYFSroot)
417 			return EPERM;
418 		error = ptyfs_chown(vp, vap->va_uid, vap->va_gid, cred, p);
419 		if (error)
420 			return error;
421 	}
422 
423 	if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL ||
424 	    vap->va_birthtime.tv_sec != VNOVAL) {
425 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
426 			return EROFS;
427 		if ((ptyfs->ptyfs_flags & SF_SNAPSHOT) != 0)
428 			return EPERM;
429 		if (cred->cr_uid != ptyfs->ptyfs_uid &&
430 		    (error = suser(cred, &p->p_acflag)) &&
431 		    ((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
432 		    (error = VOP_ACCESS(vp, VWRITE, cred, l)) != 0))
433 			return (error);
434 		if (vap->va_atime.tv_sec != VNOVAL)
435 			if (!(vp->v_mount->mnt_flag & MNT_NOATIME))
436 				ptyfs->ptyfs_flag |= PTYFS_ACCESS;
437 		if (vap->va_mtime.tv_sec != VNOVAL)
438 			ptyfs->ptyfs_flag |= PTYFS_CHANGE | PTYFS_MODIFY;
439 		if (vap->va_birthtime.tv_sec != VNOVAL)
440 			ptyfs->ptyfs_birthtime = vap->va_birthtime;
441 		ptyfs->ptyfs_flag |= PTYFS_CHANGE;
442 		error = ptyfs_update(vp, &vap->va_atime, &vap->va_mtime, 0);
443 		if (error)
444 			return error;
445 	}
446 	if (vap->va_mode != (mode_t)VNOVAL) {
447 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
448 			return EROFS;
449 		if (ptyfs->ptyfs_type == PTYFSroot)
450 			return EPERM;
451 		if ((ptyfs->ptyfs_flags & SF_SNAPSHOT) != 0 &&
452 		    (vap->va_mode &
453 		    (S_IXUSR|S_IWUSR|S_IXGRP|S_IWGRP|S_IXOTH|S_IWOTH)))
454 			return EPERM;
455 		error = ptyfs_chmod(vp, vap->va_mode, cred, p);
456 		if (error)
457 			return error;
458 	}
459 	VN_KNOTE(vp, NOTE_ATTRIB);
460 	return 0;
461 }
462 
463 /*
464  * Change the mode on a file.
465  * Inode must be locked before calling.
466  */
467 static int
468 ptyfs_chmod(struct vnode *vp, mode_t mode, struct ucred *cred, struct proc *p)
469 {
470 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
471 	int error;
472 
473 	if (cred->cr_uid != ptyfs->ptyfs_uid &&
474 	    (error = suser(cred, &p->p_acflag)) != 0)
475 		return error;
476 	ptyfs->ptyfs_mode &= ~ALLPERMS;
477 	ptyfs->ptyfs_mode |= (mode & ALLPERMS);
478 	return 0;
479 }
480 
481 /*
482  * Perform chown operation on inode ip;
483  * inode must be locked prior to call.
484  */
485 static int
486 ptyfs_chown(struct vnode *vp, uid_t uid, gid_t gid, struct ucred *cred,
487     struct proc *p)
488 {
489 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
490 	int		error;
491 
492 	if (uid == (uid_t)VNOVAL)
493 		uid = ptyfs->ptyfs_uid;
494 	if (gid == (gid_t)VNOVAL)
495 		gid = ptyfs->ptyfs_gid;
496 	/*
497 	 * If we don't own the file, are trying to change the owner
498 	 * of the file, or are not a member of the target group,
499 	 * the caller's credentials must imply super-user privilege
500 	 * or the call fails.
501 	 */
502 	if ((cred->cr_uid != ptyfs->ptyfs_uid || uid != ptyfs->ptyfs_uid ||
503 	    (gid != ptyfs->ptyfs_gid &&
504 	     !(cred->cr_gid == gid || groupmember((gid_t)gid, cred)))) &&
505 	    ((error = suser(cred, &p->p_acflag)) != 0))
506 		return error;
507 
508 	ptyfs->ptyfs_gid = gid;
509 	ptyfs->ptyfs_uid = uid;
510 	return 0;
511 }
512 
513 /*
514  * implement access checking.
515  *
516  * actually, the check for super-user is slightly
517  * broken since it will allow read access to write-only
518  * objects.  this doesn't cause any particular trouble
519  * but does mean that the i/o entry points need to check
520  * that the operation really does make sense.
521  */
522 int
523 ptyfs_access(void *v)
524 {
525 	struct vop_access_args /* {
526 		struct vnode *a_vp;
527 		int a_mode;
528 		struct ucred *a_cred;
529 		struct lwp *a_l;
530 	} */ *ap = v;
531 	struct vattr va;
532 	int error;
533 
534 	if ((error = VOP_GETATTR(ap->a_vp, &va, ap->a_cred, ap->a_l)) != 0)
535 		return error;
536 
537 	return vaccess(va.va_type, va.va_mode,
538 	    va.va_uid, va.va_gid, ap->a_mode, ap->a_cred);
539 }
540 
541 /*
542  * lookup.  this is incredibly complicated in the
543  * general case, however for most pseudo-filesystems
544  * very little needs to be done.
545  *
546  * Locking isn't hard here, just poorly documented.
547  *
548  * If we're looking up ".", just vref the parent & return it.
549  *
550  * If we're looking up "..", unlock the parent, and lock "..". If everything
551  * went ok, and we're on the last component and the caller requested the
552  * parent locked, try to re-lock the parent. We do this to prevent lock
553  * races.
554  *
555  * For anything else, get the needed node. Then unlock the parent if not
556  * the last component or not LOCKPARENT (i.e. if we wouldn't re-lock the
557  * parent in the .. case).
558  *
559  * We try to exit with the parent locked in error cases.
560  */
561 int
562 ptyfs_lookup(void *v)
563 {
564 	struct vop_lookup_args /* {
565 		struct vnode * a_dvp;
566 		struct vnode ** a_vpp;
567 		struct componentname * a_cnp;
568 	} */ *ap = v;
569 	struct componentname *cnp = ap->a_cnp;
570 	struct vnode **vpp = ap->a_vpp;
571 	struct vnode *dvp = ap->a_dvp;
572 	const char *pname = cnp->cn_nameptr;
573 	struct ptyfsnode *ptyfs;
574 	int pty, error, wantpunlock;
575 
576 	*vpp = NULL;
577 	cnp->cn_flags &= ~PDIRUNLOCK;
578 
579 	if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
580 		return EROFS;
581 
582 	if (cnp->cn_namelen == 1 && *pname == '.') {
583 		*vpp = dvp;
584 		VREF(dvp);
585 		return 0;
586 	}
587 
588 	wantpunlock = ~cnp->cn_flags & (LOCKPARENT | ISLASTCN);
589 	ptyfs = VTOPTYFS(dvp);
590 	switch (ptyfs->ptyfs_type) {
591 	case PTYFSroot:
592 		/*
593 		 * Shouldn't get here with .. in the root node.
594 		 */
595 		if (cnp->cn_flags & ISDOTDOT)
596 			return EIO;
597 
598 		pty = atoi(pname, cnp->cn_namelen);
599 
600 		if (pty < 0 || pty >= npty || pty_isfree(pty, 1))
601 			break;
602 
603 		error = ptyfs_allocvp(dvp->v_mount, vpp, PTYFSpts, pty,
604 		    curlwp);
605 		if (error == 0 && wantpunlock) {
606 			VOP_UNLOCK(dvp, 0);
607 			cnp->cn_flags |= PDIRUNLOCK;
608 		}
609 		return error;
610 
611 	default:
612 		return ENOTDIR;
613 	}
614 
615 	return cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS;
616 }
617 
618 /*
619  * readdir returns directory entries from ptyfsnode (vp).
620  *
621  * the strategy here with ptyfs is to generate a single
622  * directory entry at a time (struct dirent) and then
623  * copy that out to userland using uiomove.  a more efficent
624  * though more complex implementation, would try to minimize
625  * the number of calls to uiomove().  for ptyfs, this is
626  * hardly worth the added code complexity.
627  *
628  * this should just be done through read()
629  */
630 int
631 ptyfs_readdir(void *v)
632 {
633 	struct vop_readdir_args /* {
634 		struct vnode *a_vp;
635 		struct uio *a_uio;
636 		struct ucred *a_cred;
637 		int *a_eofflag;
638 		off_t **a_cookies;
639 		int *a_ncookies;
640 	} */ *ap = v;
641 	struct uio *uio = ap->a_uio;
642 	struct dirent d;
643 	struct ptyfsnode *ptyfs;
644 	off_t i;
645 	int error;
646 	off_t *cookies = NULL;
647 	int ncookies;
648 	struct vnode *vp;
649 	int nc = 0;
650 
651 	vp = ap->a_vp;
652 	ptyfs = VTOPTYFS(vp);
653 
654 	if (uio->uio_resid < UIO_MX)
655 		return EINVAL;
656 	if (uio->uio_offset < 0)
657 		return EINVAL;
658 
659 	error = 0;
660 	i = uio->uio_offset;
661 	(void)memset(&d, 0, sizeof(d));
662 	d.d_reclen = UIO_MX;
663 	ncookies = uio->uio_resid / UIO_MX;
664 
665 	switch (ptyfs->ptyfs_type) {
666 	case PTYFSroot: /* root */
667 
668 		if (i >= npty)
669 			return 0;
670 
671 		if (ap->a_ncookies) {
672 			ncookies = min(ncookies, (npty + 2 - i));
673 			cookies = malloc(ncookies * sizeof (off_t),
674 			    M_TEMP, M_WAITOK);
675 			*ap->a_cookies = cookies;
676 		}
677 
678 		for (; i < 2; i++) {
679 			switch (i) {
680 			case 0:		/* `.' */
681 			case 1:		/* `..' */
682 				d.d_fileno = PTYFS_FILENO(0, PTYFSroot);
683 				d.d_namlen = i + 1;
684 				(void)memcpy(d.d_name, "..", d.d_namlen);
685 				d.d_name[i + 1] = '\0';
686 				d.d_type = DT_DIR;
687 				break;
688 			}
689 			if ((error = uiomove(&d, UIO_MX, uio)) != 0)
690 				break;
691 			if (cookies)
692 				*cookies++ = i + 1;
693 			nc++;
694 		}
695 		if (error) {
696 			ncookies = nc;
697 			break;
698 		}
699 		for (; uio->uio_resid >= UIO_MX && i < npty; i++) {
700 			/* check for used ptys */
701 			if (pty_isfree(i - 2, 1))
702 				continue;
703 
704 			d.d_fileno = PTYFS_FILENO(i - 2, PTYFSpts);
705 			d.d_namlen = snprintf(d.d_name, sizeof(d.d_name),
706 			    "%lld", (long long)(i - 2));
707 			d.d_type = DT_CHR;
708 			if ((error = uiomove(&d, UIO_MX, uio)) != 0)
709 				break;
710 			if (cookies)
711 				*cookies++ = i + 1;
712 			nc++;
713 		}
714 		ncookies = nc;
715 		break;
716 
717 	default:
718 		error = ENOTDIR;
719 		break;
720 	}
721 
722 	if (ap->a_ncookies) {
723 		if (error) {
724 			if (cookies)
725 				free(*ap->a_cookies, M_TEMP);
726 			*ap->a_ncookies = 0;
727 			*ap->a_cookies = NULL;
728 		} else
729 			*ap->a_ncookies = ncookies;
730 	}
731 	uio->uio_offset = i;
732 	return error;
733 }
734 
735 int
736 ptyfs_open(void *v)
737 {
738 	struct vop_open_args /* {
739 		struct vnode *a_vp;
740 		int  a_mode;
741 		struct ucred *a_cred;
742 		struct lwp *a_l;
743 	} */ *ap = v;
744 	struct vnode *vp = ap->a_vp;
745 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
746 
747 	ptyfs->ptyfs_flag |= PTYFS_CHANGE|PTYFS_ACCESS;
748 	switch (ptyfs->ptyfs_type) {
749 	case PTYFSpts:
750 	case PTYFSptc:
751 		return spec_open(v);
752 	case PTYFSroot:
753 		return 0;
754 	default:
755 		return EINVAL;
756 	}
757 }
758 
759 int
760 ptyfs_close(void *v)
761 {
762 	struct vop_close_args /* {
763 		struct vnode *a_vp;
764 		int  a_fflag;
765 		struct ucred *a_cred;
766 		struct lwp *a_l;
767 	} */ *ap = v;
768 	struct vnode *vp = ap->a_vp;
769 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
770 
771         simple_lock(&vp->v_interlock);
772         if (vp->v_usecount > 1)
773 		PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
774         simple_unlock(&vp->v_interlock);
775 
776 	switch (ptyfs->ptyfs_type) {
777 	case PTYFSpts:
778 	case PTYFSptc:
779 		return spec_close(v);
780 	case PTYFSroot:
781 		return 0;
782 	default:
783 		return EINVAL;
784 	}
785 }
786 
787 int
788 ptyfs_read(void *v)
789 {
790 	struct vop_read_args /* {
791 		struct vnode *a_vp;
792 		struct uio *a_uio;
793 		int  a_ioflag;
794 		struct ucred *a_cred;
795 	} */ *ap = v;
796 	struct timespec ts;
797 	struct vnode *vp = ap->a_vp;
798 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
799 	int error;
800 
801 	ptyfs->ptyfs_flag |= PTYFS_ACCESS;
802 	/* hardclock() resolution is good enough for ptyfs */
803 	TIMEVAL_TO_TIMESPEC(&time, &ts);
804 	(void)ptyfs_update(vp, &ts, &ts, 0);
805 
806 	switch (ptyfs->ptyfs_type) {
807 	case PTYFSpts:
808 		VOP_UNLOCK(vp, 0);
809 		error = (*pts_cdevsw.d_read)(vp->v_rdev, ap->a_uio,
810 		    ap->a_ioflag);
811 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
812 		return error;
813 	case PTYFSptc:
814 		VOP_UNLOCK(vp, 0);
815 		error = (*ptc_cdevsw.d_read)(vp->v_rdev, ap->a_uio,
816 		    ap->a_ioflag);
817 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
818 		return error;
819 	default:
820 		return EOPNOTSUPP;
821 	}
822 }
823 
824 int
825 ptyfs_write(void *v)
826 {
827 	struct vop_write_args /* {
828 		struct vnode *a_vp;
829 		struct uio *a_uio;
830 		int  a_ioflag;
831 		struct ucred *a_cred;
832 	} */ *ap = v;
833 	struct timespec ts;
834 	struct vnode *vp = ap->a_vp;
835 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
836 	int error;
837 
838 	ptyfs->ptyfs_flag |= PTYFS_MODIFY;
839 	/* hardclock() resolution is good enough for ptyfs */
840 	TIMEVAL_TO_TIMESPEC(&time, &ts);
841 	(void)ptyfs_update(vp, &ts, &ts, 0);
842 
843 	switch (ptyfs->ptyfs_type) {
844 	case PTYFSpts:
845 		VOP_UNLOCK(vp, 0);
846 		error = (*pts_cdevsw.d_write)(vp->v_rdev, ap->a_uio,
847 		    ap->a_ioflag);
848 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
849 		return error;
850 	case PTYFSptc:
851 		VOP_UNLOCK(vp, 0);
852 		error = (*ptc_cdevsw.d_write)(vp->v_rdev, ap->a_uio,
853 		    ap->a_ioflag);
854 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
855 		return error;
856 	default:
857 		return EOPNOTSUPP;
858 	}
859 }
860 
861 int
862 ptyfs_ioctl(void *v)
863 {
864 	struct vop_ioctl_args /* {
865 		struct vnode *a_vp;
866 		u_long a_command;
867 		void *a_data;
868 		int  a_fflag;
869 		struct ucred *a_cred;
870 		struct lwp *a_l;
871 	} */ *ap = v;
872 	struct vnode *vp = ap->a_vp;
873 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
874 
875 	switch (ptyfs->ptyfs_type) {
876 	case PTYFSpts:
877 		return (*pts_cdevsw.d_ioctl)(vp->v_rdev, ap->a_command,
878 		    ap->a_data, ap->a_fflag, ap->a_l);
879 	case PTYFSptc:
880 		return (*ptc_cdevsw.d_ioctl)(vp->v_rdev, ap->a_command,
881 		    ap->a_data, ap->a_fflag, ap->a_l);
882 	default:
883 		return EOPNOTSUPP;
884 	}
885 }
886 
887 int
888 ptyfs_poll(void *v)
889 {
890 	struct vop_poll_args /* {
891 		struct vnode *a_vp;
892 		int a_events;
893 		struct lwp *a_l;
894 	} */ *ap = v;
895 	struct vnode *vp = ap->a_vp;
896 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
897 
898 	switch (ptyfs->ptyfs_type) {
899 	case PTYFSpts:
900 		return (*pts_cdevsw.d_poll)(vp->v_rdev, ap->a_events, ap->a_l);
901 	case PTYFSptc:
902 		return (*ptc_cdevsw.d_poll)(vp->v_rdev, ap->a_events, ap->a_l);
903 	default:
904 		return genfs_poll(v);
905 	}
906 }
907 
908 int
909 ptyfs_kqfilter(void *v)
910 {
911 	struct vop_kqfilter_args /* {
912 		struct vnode *a_vp;
913 		struct knote *a_kn;
914 	} */ *ap = v;
915 	struct vnode *vp = ap->a_vp;
916 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
917 
918 	switch (ptyfs->ptyfs_type) {
919 	case PTYFSpts:
920 		return (*pts_cdevsw.d_kqfilter)(vp->v_rdev, ap->a_kn);
921 	case PTYFSptc:
922 		return (*ptc_cdevsw.d_kqfilter)(vp->v_rdev, ap->a_kn);
923 	default:
924 		return genfs_kqfilter(v);
925 	}
926 }
927 
928 static int
929 ptyfs_update(struct vnode *vp, const struct timespec *acc,
930     const struct timespec *mod, int flags)
931 {
932 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
933 
934 	if (vp->v_mount->mnt_flag & MNT_RDONLY)
935 		return 0;
936 
937 	PTYFS_ITIMES(ptyfs, acc, mod, NULL);
938 	return 0;
939 }
940 
941 void
942 ptyfs_itimes(struct ptyfsnode *ptyfs, const struct timespec *acc,
943     const struct timespec *mod, const struct timespec *cre)
944 {
945 	struct timespec *ts = NULL, tsb;
946 
947 	KASSERT(ptyfs->ptyfs_flag & (PTYFS_ACCESS|PTYFS_CHANGE|PTYFS_MODIFY));
948 	if (ptyfs->ptyfs_flag & (PTYFS_ACCESS|PTYFS_MODIFY)) {
949 		if (acc == NULL)
950 			acc = ts == NULL ? (ts = nanotime(&tsb)) : ts;
951 		ptyfs->ptyfs_atime = *acc;
952 	}
953 	if (ptyfs->ptyfs_flag & PTYFS_MODIFY) {
954 		if (mod == NULL)
955 			mod = ts == NULL ? (ts = nanotime(&tsb)) : ts;
956 		ptyfs->ptyfs_mtime = *mod;
957 	}
958 	if (ptyfs->ptyfs_flag & PTYFS_CHANGE) {
959 		if (cre == NULL)
960 			cre = ts == NULL ? (ts = nanotime(&tsb)) : ts;
961 		ptyfs->ptyfs_ctime = *cre;
962 	}
963 	ptyfs->ptyfs_flag &= ~(PTYFS_ACCESS|PTYFS_CHANGE|PTYFS_MODIFY);
964 }
965 
966 /*
967  * convert decimal ascii to int
968  */
969 static int
970 atoi(const char *b, size_t len)
971 {
972 	int p = 0;
973 
974 	while (len--) {
975 		char c = *b++;
976 		if (c < '0' || c > '9')
977 			return -1;
978 		p = 10 * p + (c - '0');
979 	}
980 
981 	return p;
982 }
983