xref: /netbsd-src/sys/fs/ptyfs/ptyfs_vnops.c (revision 7788a0781fe6ff2cce37368b4578a7ade0850cb1)
1 /*	$NetBSD: ptyfs_vnops.c,v 1.41 2013/03/18 19:35:38 plunky 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 1.41 2013/03/18 19:35:38 plunky 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 #include <sys/kauth.h>
100 
101 #include <uvm/uvm_extern.h>	/* for PAGE_SIZE */
102 
103 #include <machine/reg.h>
104 
105 #include <fs/ptyfs/ptyfs.h>
106 #include <miscfs/genfs/genfs.h>
107 #include <miscfs/specfs/specdev.h>
108 
109 MALLOC_DECLARE(M_PTYFSTMP);
110 
111 /*
112  * Vnode Operations.
113  *
114  */
115 
116 int	ptyfs_lookup	(void *);
117 #define	ptyfs_create	genfs_eopnotsupp
118 #define	ptyfs_mknod	genfs_eopnotsupp
119 int	ptyfs_open	(void *);
120 int	ptyfs_close	(void *);
121 int	ptyfs_access	(void *);
122 int	ptyfs_getattr	(void *);
123 int	ptyfs_setattr	(void *);
124 int	ptyfs_read	(void *);
125 int	ptyfs_write	(void *);
126 #define	ptyfs_fcntl	genfs_fcntl
127 int	ptyfs_ioctl	(void *);
128 int	ptyfs_poll	(void *);
129 int	ptyfs_kqfilter	(void *);
130 #define ptyfs_revoke	genfs_revoke
131 #define	ptyfs_mmap	genfs_eopnotsupp
132 #define	ptyfs_fsync	genfs_nullop
133 #define	ptyfs_seek	genfs_nullop
134 #define	ptyfs_remove	genfs_eopnotsupp
135 #define	ptyfs_link	genfs_abortop
136 #define	ptyfs_rename	genfs_eopnotsupp
137 #define	ptyfs_mkdir	genfs_eopnotsupp
138 #define	ptyfs_rmdir	genfs_eopnotsupp
139 #define	ptyfs_symlink	genfs_abortop
140 int	ptyfs_readdir	(void *);
141 #define	ptyfs_readlink	genfs_eopnotsupp
142 #define	ptyfs_abortop	genfs_abortop
143 int	ptyfs_reclaim	(void *);
144 #define	ptyfs_lock	genfs_lock
145 #define	ptyfs_unlock	genfs_unlock
146 #define	ptyfs_bmap	genfs_badop
147 #define	ptyfs_strategy	genfs_badop
148 int	ptyfs_print	(void *);
149 int	ptyfs_pathconf	(void *);
150 #define	ptyfs_islocked	genfs_islocked
151 #define	ptyfs_advlock	genfs_einval
152 #define	ptyfs_bwrite	genfs_eopnotsupp
153 #define ptyfs_putpages	genfs_null_putpages
154 
155 static int ptyfs_update(struct vnode *, const struct timespec *,
156     const struct timespec *, int);
157 static int ptyfs_chown(struct vnode *, uid_t, gid_t, kauth_cred_t,
158     struct lwp *);
159 static int ptyfs_chmod(struct vnode *, mode_t, kauth_cred_t, struct lwp *);
160 static int atoi(const char *, size_t);
161 
162 /*
163  * ptyfs vnode operations.
164  */
165 int (**ptyfs_vnodeop_p)(void *);
166 const struct vnodeopv_entry_desc ptyfs_vnodeop_entries[] = {
167 	{ &vop_default_desc, vn_default_error },
168 	{ &vop_lookup_desc, ptyfs_lookup },		/* lookup */
169 	{ &vop_create_desc, ptyfs_create },		/* create */
170 	{ &vop_mknod_desc, ptyfs_mknod },		/* mknod */
171 	{ &vop_open_desc, ptyfs_open },			/* open */
172 	{ &vop_close_desc, ptyfs_close },		/* close */
173 	{ &vop_access_desc, ptyfs_access },		/* access */
174 	{ &vop_getattr_desc, ptyfs_getattr },		/* getattr */
175 	{ &vop_setattr_desc, ptyfs_setattr },		/* setattr */
176 	{ &vop_read_desc, ptyfs_read },			/* read */
177 	{ &vop_write_desc, ptyfs_write },		/* write */
178 	{ &vop_ioctl_desc, ptyfs_ioctl },		/* ioctl */
179 	{ &vop_fcntl_desc, ptyfs_fcntl },		/* fcntl */
180 	{ &vop_poll_desc, ptyfs_poll },			/* poll */
181 	{ &vop_kqfilter_desc, ptyfs_kqfilter },		/* kqfilter */
182 	{ &vop_revoke_desc, ptyfs_revoke },		/* revoke */
183 	{ &vop_mmap_desc, ptyfs_mmap },			/* mmap */
184 	{ &vop_fsync_desc, ptyfs_fsync },		/* fsync */
185 	{ &vop_seek_desc, ptyfs_seek },			/* seek */
186 	{ &vop_remove_desc, ptyfs_remove },		/* remove */
187 	{ &vop_link_desc, ptyfs_link },			/* link */
188 	{ &vop_rename_desc, ptyfs_rename },		/* rename */
189 	{ &vop_mkdir_desc, ptyfs_mkdir },		/* mkdir */
190 	{ &vop_rmdir_desc, ptyfs_rmdir },		/* rmdir */
191 	{ &vop_symlink_desc, ptyfs_symlink },		/* symlink */
192 	{ &vop_readdir_desc, ptyfs_readdir },		/* readdir */
193 	{ &vop_readlink_desc, ptyfs_readlink },		/* readlink */
194 	{ &vop_abortop_desc, ptyfs_abortop },		/* abortop */
195 	{ &vop_inactive_desc, spec_inactive },		/* inactive */
196 	{ &vop_reclaim_desc, ptyfs_reclaim },		/* reclaim */
197 	{ &vop_lock_desc, ptyfs_lock },			/* lock */
198 	{ &vop_unlock_desc, ptyfs_unlock },		/* unlock */
199 	{ &vop_bmap_desc, ptyfs_bmap },			/* bmap */
200 	{ &vop_strategy_desc, ptyfs_strategy },		/* strategy */
201 	{ &vop_print_desc, ptyfs_print },		/* print */
202 	{ &vop_islocked_desc, ptyfs_islocked },		/* islocked */
203 	{ &vop_pathconf_desc, ptyfs_pathconf },		/* pathconf */
204 	{ &vop_advlock_desc, ptyfs_advlock },		/* advlock */
205 	{ &vop_bwrite_desc, ptyfs_bwrite },		/* bwrite */
206 	{ &vop_putpages_desc, ptyfs_putpages },		/* putpages */
207 	{ NULL, NULL }
208 };
209 const struct vnodeopv_desc ptyfs_vnodeop_opv_desc =
210 	{ &ptyfs_vnodeop_p, ptyfs_vnodeop_entries };
211 
212 /*
213  * _reclaim is called when getnewvnode()
214  * wants to make use of an entry on the vnode
215  * free list.  at this time the filesystem needs
216  * to free any private data and remove the node
217  * from any private lists.
218  */
219 int
220 ptyfs_reclaim(void *v)
221 {
222 	struct vop_reclaim_args /* {
223 		struct vnode *a_vp;
224 	} */ *ap = v;
225 	return ptyfs_freevp(ap->a_vp);
226 }
227 
228 /*
229  * Return POSIX pathconf information applicable to special devices.
230  */
231 int
232 ptyfs_pathconf(void *v)
233 {
234 	struct vop_pathconf_args /* {
235 		struct vnode *a_vp;
236 		int a_name;
237 		register_t *a_retval;
238 	} */ *ap = v;
239 
240 	switch (ap->a_name) {
241 	case _PC_LINK_MAX:
242 		*ap->a_retval = LINK_MAX;
243 		return 0;
244 	case _PC_MAX_CANON:
245 		*ap->a_retval = MAX_CANON;
246 		return 0;
247 	case _PC_MAX_INPUT:
248 		*ap->a_retval = MAX_INPUT;
249 		return 0;
250 	case _PC_PIPE_BUF:
251 		*ap->a_retval = PIPE_BUF;
252 		return 0;
253 	case _PC_CHOWN_RESTRICTED:
254 		*ap->a_retval = 1;
255 		return 0;
256 	case _PC_VDISABLE:
257 		*ap->a_retval = _POSIX_VDISABLE;
258 		return 0;
259 	case _PC_SYNC_IO:
260 		*ap->a_retval = 1;
261 		return 0;
262 	default:
263 		return EINVAL;
264 	}
265 }
266 
267 /*
268  * _print is used for debugging.
269  * just print a readable description
270  * of (vp).
271  */
272 int
273 ptyfs_print(void *v)
274 {
275 	struct vop_print_args /* {
276 		struct vnode *a_vp;
277 	} */ *ap = v;
278 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
279 
280 	printf("tag VT_PTYFS, type %d, pty %d\n",
281 	    ptyfs->ptyfs_type, ptyfs->ptyfs_pty);
282 	return 0;
283 }
284 
285 /*
286  * Invent attributes for ptyfsnode (vp) and store
287  * them in (vap).
288  * Directories lengths are returned as zero since
289  * any real length would require the genuine size
290  * to be computed, and nothing cares anyway.
291  *
292  * this is relatively minimal for ptyfs.
293  */
294 int
295 ptyfs_getattr(void *v)
296 {
297 	struct vop_getattr_args /* {
298 		struct vnode *a_vp;
299 		struct vattr *a_vap;
300 		kauth_cred_t a_cred;
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 		kauth_cred_t a_cred;
357 	} */ *ap = v;
358 	struct vnode *vp = ap->a_vp;
359 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
360 	struct vattr *vap = ap->a_vap;
361 	kauth_cred_t cred = ap->a_cred;
362 	struct lwp *l = curlwp;
363 	int error;
364 	kauth_action_t action = KAUTH_VNODE_WRITE_FLAGS;
365 	bool changing_sysflags = false;
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 
383 		/* Immutable and append-only flags are not supported on ptyfs. */
384 		if (vap->va_flags & (IMMUTABLE | APPEND))
385 			return EINVAL;
386 
387 		/* Snapshot flag cannot be set or cleared */
388 		if ((vap->va_flags & SF_SNAPSHOT) != (ptyfs->ptyfs_flags & SF_SNAPSHOT))
389 			return EPERM;
390 
391 		if ((ptyfs->ptyfs_flags & SF_SETTABLE) != (vap->va_flags & SF_SETTABLE)) {
392 			changing_sysflags = true;
393 			action |= KAUTH_VNODE_WRITE_SYSFLAGS;
394 		}
395 
396 		error = kauth_authorize_vnode(cred, action, vp, NULL,
397 		    genfs_can_chflags(cred, vp->v_type, ptyfs->ptyfs_uid,
398 		    changing_sysflags));
399 		if (error)
400 			return error;
401 
402 		if (changing_sysflags) {
403 			ptyfs->ptyfs_flags = vap->va_flags;
404 		} else {
405 			ptyfs->ptyfs_flags &= SF_SETTABLE;
406 			ptyfs->ptyfs_flags |= (vap->va_flags & UF_SETTABLE);
407 		}
408 		ptyfs->ptyfs_status |= PTYFS_CHANGE;
409 	}
410 
411 	/*
412 	 * Go through the fields and update iff not VNOVAL.
413 	 */
414 	if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
415 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
416 			return EROFS;
417 		if (ptyfs->ptyfs_type == PTYFSroot)
418 			return EPERM;
419 		error = ptyfs_chown(vp, vap->va_uid, vap->va_gid, cred, l);
420 		if (error)
421 			return error;
422 	}
423 
424 	if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL ||
425 	    vap->va_birthtime.tv_sec != VNOVAL) {
426 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
427 			return EROFS;
428 		if ((ptyfs->ptyfs_flags & SF_SNAPSHOT) != 0)
429 			return EPERM;
430 		error = kauth_authorize_vnode(cred, KAUTH_VNODE_WRITE_TIMES, vp,
431 		    NULL, genfs_can_chtimes(vp, vap->va_vaflags,
432 		    ptyfs->ptyfs_uid, cred));
433 		if (error)
434 			return (error);
435 		if (vap->va_atime.tv_sec != VNOVAL)
436 			if (!(vp->v_mount->mnt_flag & MNT_NOATIME))
437 				ptyfs->ptyfs_status |= PTYFS_ACCESS;
438 		if (vap->va_mtime.tv_sec != VNOVAL) {
439 			ptyfs->ptyfs_status |= PTYFS_CHANGE | PTYFS_MODIFY;
440 			if (vp->v_mount->mnt_flag & MNT_RELATIME)
441 				ptyfs->ptyfs_status |= PTYFS_ACCESS;
442 		}
443 		if (vap->va_birthtime.tv_sec != VNOVAL)
444 			ptyfs->ptyfs_birthtime = vap->va_birthtime;
445 		ptyfs->ptyfs_status |= PTYFS_CHANGE;
446 		error = ptyfs_update(vp, &vap->va_atime, &vap->va_mtime, 0);
447 		if (error)
448 			return error;
449 	}
450 	if (vap->va_mode != (mode_t)VNOVAL) {
451 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
452 			return EROFS;
453 		if (ptyfs->ptyfs_type == PTYFSroot)
454 			return EPERM;
455 		if ((ptyfs->ptyfs_flags & SF_SNAPSHOT) != 0 &&
456 		    (vap->va_mode &
457 		    (S_IXUSR|S_IWUSR|S_IXGRP|S_IWGRP|S_IXOTH|S_IWOTH)))
458 			return EPERM;
459 		error = ptyfs_chmod(vp, vap->va_mode, cred, l);
460 		if (error)
461 			return error;
462 	}
463 	VN_KNOTE(vp, NOTE_ATTRIB);
464 	return 0;
465 }
466 
467 /*
468  * Change the mode on a file.
469  * Inode must be locked before calling.
470  */
471 static int
472 ptyfs_chmod(struct vnode *vp, mode_t mode, kauth_cred_t cred, struct lwp *l)
473 {
474 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
475 	int error;
476 
477 	error = kauth_authorize_vnode(cred, KAUTH_VNODE_WRITE_SECURITY, vp,
478 	    NULL, genfs_can_chmod(vp->v_type, cred, ptyfs->ptyfs_uid,
479 	    ptyfs->ptyfs_gid, mode));
480 	if (error)
481 		return (error);
482 
483 	ptyfs->ptyfs_mode &= ~ALLPERMS;
484 	ptyfs->ptyfs_mode |= (mode & ALLPERMS);
485 	return 0;
486 }
487 
488 /*
489  * Perform chown operation on inode ip;
490  * inode must be locked prior to call.
491  */
492 static int
493 ptyfs_chown(struct vnode *vp, uid_t uid, gid_t gid, kauth_cred_t cred,
494     struct lwp *l)
495 {
496 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
497 	int error;
498 
499 	if (uid == (uid_t)VNOVAL)
500 		uid = ptyfs->ptyfs_uid;
501 	if (gid == (gid_t)VNOVAL)
502 		gid = ptyfs->ptyfs_gid;
503 
504 	error = kauth_authorize_vnode(cred, KAUTH_VNODE_CHANGE_OWNERSHIP, vp,
505 	    NULL, genfs_can_chown(cred, ptyfs->ptyfs_uid, ptyfs->ptyfs_gid,
506 	    uid, gid));
507 	if (error)
508 		return (error);
509 
510 	ptyfs->ptyfs_gid = gid;
511 	ptyfs->ptyfs_uid = uid;
512 	return 0;
513 }
514 
515 /*
516  * implement access checking.
517  *
518  * actually, the check for super-user is slightly
519  * broken since it will allow read access to write-only
520  * objects.  this doesn't cause any particular trouble
521  * but does mean that the i/o entry points need to check
522  * that the operation really does make sense.
523  */
524 int
525 ptyfs_access(void *v)
526 {
527 	struct vop_access_args /* {
528 		struct vnode *a_vp;
529 		int a_mode;
530 		kauth_cred_t a_cred;
531 	} */ *ap = v;
532 	struct vattr va;
533 	int error;
534 
535 	if ((error = VOP_GETATTR(ap->a_vp, &va, ap->a_cred)) != 0)
536 		return error;
537 
538 	return kauth_authorize_vnode(ap->a_cred,
539 	    KAUTH_ACCESS_ACTION(ap->a_mode, ap->a_vp->v_type, va.va_mode),
540 	    ap->a_vp, NULL, genfs_can_access(va.va_type, va.va_mode, va.va_uid,
541 	    va.va_gid, ap->a_mode, ap->a_cred));
542 
543 	return error;
544 }
545 
546 /*
547  * lookup.  this is incredibly complicated in the
548  * general case, however for most pseudo-filesystems
549  * very little needs to be done.
550  *
551  * Locking isn't hard here, just poorly documented.
552  *
553  * If we're looking up ".", just vref the parent & return it.
554  *
555  * If we're looking up "..", unlock the parent, and lock "..". If everything
556  * went ok, try to re-lock the parent. We do this to prevent lock races.
557  *
558  * For anything else, get the needed node.
559  *
560  * We try to exit with the parent locked in error cases.
561  */
562 int
563 ptyfs_lookup(void *v)
564 {
565 	struct vop_lookup_args /* {
566 		struct vnode * a_dvp;
567 		struct vnode ** a_vpp;
568 		struct componentname * a_cnp;
569 	} */ *ap = v;
570 	struct componentname *cnp = ap->a_cnp;
571 	struct vnode **vpp = ap->a_vpp;
572 	struct vnode *dvp = ap->a_dvp;
573 	const char *pname = cnp->cn_nameptr;
574 	struct ptyfsnode *ptyfs;
575 	int pty, error;
576 
577 	*vpp = NULL;
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 	ptyfs = VTOPTYFS(dvp);
589 	switch (ptyfs->ptyfs_type) {
590 	case PTYFSroot:
591 		/*
592 		 * Shouldn't get here with .. in the root node.
593 		 */
594 		if (cnp->cn_flags & ISDOTDOT)
595 			return EIO;
596 
597 		pty = atoi(pname, cnp->cn_namelen);
598 
599 		if (pty < 0 || pty >= npty || pty_isfree(pty, 1))
600 			break;
601 
602 		error = ptyfs_allocvp(dvp->v_mount, vpp, PTYFSpts, pty,
603 		    curlwp);
604 		return error;
605 
606 	default:
607 		return ENOTDIR;
608 	}
609 
610 	return cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS;
611 }
612 
613 /*
614  * readdir returns directory entries from ptyfsnode (vp).
615  *
616  * the strategy here with ptyfs is to generate a single
617  * directory entry at a time (struct dirent) and then
618  * copy that out to userland using uiomove.  a more efficent
619  * though more complex implementation, would try to minimize
620  * the number of calls to uiomove().  for ptyfs, this is
621  * hardly worth the added code complexity.
622  *
623  * this should just be done through read()
624  */
625 int
626 ptyfs_readdir(void *v)
627 {
628 	struct vop_readdir_args /* {
629 		struct vnode *a_vp;
630 		struct uio *a_uio;
631 		kauth_cred_t a_cred;
632 		int *a_eofflag;
633 		off_t **a_cookies;
634 		int *a_ncookies;
635 	} */ *ap = v;
636 	struct uio *uio = ap->a_uio;
637 	struct dirent *dp;
638 	struct ptyfsnode *ptyfs;
639 	off_t i;
640 	int error;
641 	off_t *cookies = NULL;
642 	int ncookies;
643 	struct vnode *vp;
644 	int nc = 0;
645 
646 	vp = ap->a_vp;
647 	ptyfs = VTOPTYFS(vp);
648 
649 	if (uio->uio_resid < UIO_MX)
650 		return EINVAL;
651 	if (uio->uio_offset < 0)
652 		return EINVAL;
653 
654 	dp = malloc(sizeof(struct dirent), M_PTYFSTMP, M_WAITOK | M_ZERO);
655 
656 	error = 0;
657 	i = uio->uio_offset;
658 	dp->d_reclen = UIO_MX;
659 	ncookies = uio->uio_resid / UIO_MX;
660 
661 	if (ptyfs->ptyfs_type != PTYFSroot) {
662 		error = ENOTDIR;
663 		goto out;
664 	}
665 
666 	if (i >= npty)
667 		goto out;
668 
669 	if (ap->a_ncookies) {
670 		ncookies = min(ncookies, (npty + 2 - i));
671 		cookies = malloc(ncookies * sizeof (off_t),
672 		    M_TEMP, M_WAITOK);
673 		*ap->a_cookies = cookies;
674 	}
675 
676 	for (; i < 2; i++) {
677 		/* `.' and/or `..' */
678 		dp->d_fileno = PTYFS_FILENO(0, PTYFSroot);
679 		dp->d_namlen = i + 1;
680 		(void)memcpy(dp->d_name, "..", dp->d_namlen);
681 		dp->d_name[i + 1] = '\0';
682 		dp->d_type = DT_DIR;
683 		if ((error = uiomove(dp, UIO_MX, uio)) != 0)
684 			goto out;
685 		if (cookies)
686 			*cookies++ = i + 1;
687 		nc++;
688 	}
689 	for (; uio->uio_resid >= UIO_MX && i < npty; i++) {
690 		/* check for used ptys */
691 		if (pty_isfree(i - 2, 1))
692 			continue;
693 
694 		dp->d_fileno = PTYFS_FILENO(i - 2, PTYFSpts);
695 		dp->d_namlen = snprintf(dp->d_name, sizeof(dp->d_name),
696 		    "%lld", (long long)(i - 2));
697 		dp->d_type = DT_CHR;
698 		if ((error = uiomove(dp, UIO_MX, uio)) != 0)
699 			goto out;
700 		if (cookies)
701 			*cookies++ = i + 1;
702 		nc++;
703 	}
704 
705 out:
706 	/* not pertinent in error cases */
707 	ncookies = nc;
708 
709 	if (ap->a_ncookies) {
710 		if (error) {
711 			if (cookies)
712 				free(*ap->a_cookies, M_TEMP);
713 			*ap->a_ncookies = 0;
714 			*ap->a_cookies = NULL;
715 		} else
716 			*ap->a_ncookies = ncookies;
717 	}
718 	uio->uio_offset = i;
719 	free(dp, M_PTYFSTMP);
720 	return error;
721 }
722 
723 int
724 ptyfs_open(void *v)
725 {
726 	struct vop_open_args /* {
727 		struct vnode *a_vp;
728 		int  a_mode;
729 		kauth_cred_t a_cred;
730 	} */ *ap = v;
731 	struct vnode *vp = ap->a_vp;
732 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
733 
734 	switch (ptyfs->ptyfs_type) {
735 	case PTYFSpts:
736 	case PTYFSptc:
737 		return spec_open(v);
738 	case PTYFSroot:
739 		return 0;
740 	default:
741 		return EINVAL;
742 	}
743 }
744 
745 int
746 ptyfs_close(void *v)
747 {
748 	struct vop_close_args /* {
749 		struct vnode *a_vp;
750 		int  a_fflag;
751 		kauth_cred_t a_cred;
752 	} */ *ap = v;
753 	struct vnode *vp = ap->a_vp;
754 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
755 
756 	mutex_enter(vp->v_interlock);
757 	if (vp->v_usecount > 1)
758 		PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
759 	mutex_exit(vp->v_interlock);
760 
761 	switch (ptyfs->ptyfs_type) {
762 	case PTYFSpts:
763 	case PTYFSptc:
764 		return spec_close(v);
765 	case PTYFSroot:
766 		return 0;
767 	default:
768 		return EINVAL;
769 	}
770 }
771 
772 int
773 ptyfs_read(void *v)
774 {
775 	struct vop_read_args /* {
776 		struct vnode *a_vp;
777 		struct uio *a_uio;
778 		int  a_ioflag;
779 		kauth_cred_t a_cred;
780 	} */ *ap = v;
781 	struct timespec ts;
782 	struct vnode *vp = ap->a_vp;
783 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
784 	int error;
785 
786 	if (vp->v_type == VDIR)
787 		return EISDIR;
788 
789 	ptyfs->ptyfs_status |= PTYFS_ACCESS;
790 	/* hardclock() resolution is good enough for ptyfs */
791 	getnanotime(&ts);
792 	(void)ptyfs_update(vp, &ts, &ts, 0);
793 
794 	switch (ptyfs->ptyfs_type) {
795 	case PTYFSpts:
796 	case PTYFSptc:
797 		VOP_UNLOCK(vp);
798 		error = cdev_read(vp->v_rdev, ap->a_uio, ap->a_ioflag);
799 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
800 		return error;
801 	default:
802 		return EOPNOTSUPP;
803 	}
804 }
805 
806 int
807 ptyfs_write(void *v)
808 {
809 	struct vop_write_args /* {
810 		struct vnode *a_vp;
811 		struct uio *a_uio;
812 		int  a_ioflag;
813 		kauth_cred_t a_cred;
814 	} */ *ap = v;
815 	struct timespec ts;
816 	struct vnode *vp = ap->a_vp;
817 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
818 	int error;
819 
820 	ptyfs->ptyfs_status |= PTYFS_MODIFY;
821 	getnanotime(&ts);
822 	(void)ptyfs_update(vp, &ts, &ts, 0);
823 
824 	switch (ptyfs->ptyfs_type) {
825 	case PTYFSpts:
826 	case PTYFSptc:
827 		VOP_UNLOCK(vp);
828 		error = cdev_write(vp->v_rdev, ap->a_uio, ap->a_ioflag);
829 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
830 		return error;
831 	default:
832 		return EOPNOTSUPP;
833 	}
834 }
835 
836 int
837 ptyfs_ioctl(void *v)
838 {
839 	struct vop_ioctl_args /* {
840 		struct vnode *a_vp;
841 		u_long a_command;
842 		void *a_data;
843 		int  a_fflag;
844 		kauth_cred_t a_cred;
845 	} */ *ap = v;
846 	struct vnode *vp = ap->a_vp;
847 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
848 
849 	switch (ptyfs->ptyfs_type) {
850 	case PTYFSpts:
851 	case PTYFSptc:
852 		return cdev_ioctl(vp->v_rdev, ap->a_command,
853 		    ap->a_data, ap->a_fflag, curlwp);
854 	default:
855 		return EOPNOTSUPP;
856 	}
857 }
858 
859 int
860 ptyfs_poll(void *v)
861 {
862 	struct vop_poll_args /* {
863 		struct vnode *a_vp;
864 		int a_events;
865 	} */ *ap = v;
866 	struct vnode *vp = ap->a_vp;
867 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
868 
869 	switch (ptyfs->ptyfs_type) {
870 	case PTYFSpts:
871 	case PTYFSptc:
872 		return cdev_poll(vp->v_rdev, ap->a_events, curlwp);
873 	default:
874 		return genfs_poll(v);
875 	}
876 }
877 
878 int
879 ptyfs_kqfilter(void *v)
880 {
881 	struct vop_kqfilter_args /* {
882 		struct vnode *a_vp;
883 		struct knote *a_kn;
884 	} */ *ap = v;
885 	struct vnode *vp = ap->a_vp;
886 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
887 
888 	switch (ptyfs->ptyfs_type) {
889 	case PTYFSpts:
890 	case PTYFSptc:
891 		return cdev_kqfilter(vp->v_rdev, ap->a_kn);
892 	default:
893 		return genfs_kqfilter(v);
894 	}
895 }
896 
897 static int
898 ptyfs_update(struct vnode *vp, const struct timespec *acc,
899     const struct timespec *mod, int flags)
900 {
901 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
902 
903 	if (vp->v_mount->mnt_flag & MNT_RDONLY)
904 		return 0;
905 
906 	PTYFS_ITIMES(ptyfs, acc, mod, NULL);
907 	return 0;
908 }
909 
910 void
911 ptyfs_itimes(struct ptyfsnode *ptyfs, const struct timespec *acc,
912     const struct timespec *mod, const struct timespec *cre)
913 {
914 	struct timespec now;
915 
916 	KASSERT(ptyfs->ptyfs_status & (PTYFS_ACCESS|PTYFS_CHANGE|PTYFS_MODIFY));
917 
918 	getnanotime(&now);
919 	if (ptyfs->ptyfs_status & PTYFS_ACCESS) {
920 		if (acc == NULL)
921 			acc = &now;
922 		ptyfs->ptyfs_atime = *acc;
923 	}
924 	if (ptyfs->ptyfs_status & PTYFS_MODIFY) {
925 		if (mod == NULL)
926 			mod = &now;
927 		ptyfs->ptyfs_mtime = *mod;
928 	}
929 	if (ptyfs->ptyfs_status & PTYFS_CHANGE) {
930 		if (cre == NULL)
931 			cre = &now;
932 		ptyfs->ptyfs_ctime = *cre;
933 	}
934 	ptyfs->ptyfs_status &= ~(PTYFS_ACCESS|PTYFS_CHANGE|PTYFS_MODIFY);
935 }
936 
937 /*
938  * convert decimal ascii to int
939  */
940 static int
941 atoi(const char *b, size_t len)
942 {
943 	int p = 0;
944 
945 	while (len--) {
946 		char c = *b++;
947 		if (c < '0' || c > '9')
948 			return -1;
949 		p = 10 * p + (c - '0');
950 	}
951 
952 	return p;
953 }
954