xref: /netbsd-src/sys/fs/ptyfs/ptyfs_vnops.c (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
1 /*	$NetBSD: ptyfs_vnops.c,v 1.54 2017/05/26 14:21:00 riastradh 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 1.54 2017/05/26 14:21:00 riastradh 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 int	ptyfs_inactive	(void *);
145 #define	ptyfs_lock	genfs_lock
146 #define	ptyfs_unlock	genfs_unlock
147 #define	ptyfs_bmap	genfs_badop
148 #define	ptyfs_strategy	genfs_badop
149 int	ptyfs_print	(void *);
150 int	ptyfs_pathconf	(void *);
151 #define	ptyfs_islocked	genfs_islocked
152 int	ptyfs_advlock	(void *);
153 #define	ptyfs_bwrite	genfs_eopnotsupp
154 #define ptyfs_putpages	genfs_null_putpages
155 
156 static int ptyfs_update(struct vnode *, const struct timespec *,
157     const struct timespec *, int);
158 static int ptyfs_chown(struct vnode *, uid_t, gid_t, kauth_cred_t,
159     struct lwp *);
160 static int ptyfs_chmod(struct vnode *, mode_t, kauth_cred_t, struct lwp *);
161 static int atoi(const char *, size_t);
162 
163 /*
164  * ptyfs vnode operations.
165  */
166 int (**ptyfs_vnodeop_p)(void *);
167 const struct vnodeopv_entry_desc ptyfs_vnodeop_entries[] = {
168 	{ &vop_default_desc, vn_default_error },
169 	{ &vop_lookup_desc, ptyfs_lookup },		/* lookup */
170 	{ &vop_create_desc, ptyfs_create },		/* create */
171 	{ &vop_mknod_desc, ptyfs_mknod },		/* mknod */
172 	{ &vop_open_desc, ptyfs_open },			/* open */
173 	{ &vop_close_desc, ptyfs_close },		/* close */
174 	{ &vop_access_desc, ptyfs_access },		/* access */
175 	{ &vop_getattr_desc, ptyfs_getattr },		/* getattr */
176 	{ &vop_setattr_desc, ptyfs_setattr },		/* setattr */
177 	{ &vop_read_desc, ptyfs_read },			/* read */
178 	{ &vop_write_desc, ptyfs_write },		/* write */
179 	{ &vop_fallocate_desc, genfs_eopnotsupp },	/* fallocate */
180 	{ &vop_fdiscard_desc, genfs_eopnotsupp },	/* fdiscard */
181 	{ &vop_ioctl_desc, ptyfs_ioctl },		/* ioctl */
182 	{ &vop_fcntl_desc, ptyfs_fcntl },		/* fcntl */
183 	{ &vop_poll_desc, ptyfs_poll },			/* poll */
184 	{ &vop_kqfilter_desc, ptyfs_kqfilter },		/* kqfilter */
185 	{ &vop_revoke_desc, ptyfs_revoke },		/* revoke */
186 	{ &vop_mmap_desc, ptyfs_mmap },			/* mmap */
187 	{ &vop_fsync_desc, ptyfs_fsync },		/* fsync */
188 	{ &vop_seek_desc, ptyfs_seek },			/* seek */
189 	{ &vop_remove_desc, ptyfs_remove },		/* remove */
190 	{ &vop_link_desc, ptyfs_link },			/* link */
191 	{ &vop_rename_desc, ptyfs_rename },		/* rename */
192 	{ &vop_mkdir_desc, ptyfs_mkdir },		/* mkdir */
193 	{ &vop_rmdir_desc, ptyfs_rmdir },		/* rmdir */
194 	{ &vop_symlink_desc, ptyfs_symlink },		/* symlink */
195 	{ &vop_readdir_desc, ptyfs_readdir },		/* readdir */
196 	{ &vop_readlink_desc, ptyfs_readlink },		/* readlink */
197 	{ &vop_abortop_desc, ptyfs_abortop },		/* abortop */
198 	{ &vop_inactive_desc, ptyfs_inactive },		/* inactive */
199 	{ &vop_reclaim_desc, ptyfs_reclaim },		/* reclaim */
200 	{ &vop_lock_desc, ptyfs_lock },			/* lock */
201 	{ &vop_unlock_desc, ptyfs_unlock },		/* unlock */
202 	{ &vop_bmap_desc, ptyfs_bmap },			/* bmap */
203 	{ &vop_strategy_desc, ptyfs_strategy },		/* strategy */
204 	{ &vop_print_desc, ptyfs_print },		/* print */
205 	{ &vop_islocked_desc, ptyfs_islocked },		/* islocked */
206 	{ &vop_pathconf_desc, ptyfs_pathconf },		/* pathconf */
207 	{ &vop_advlock_desc, ptyfs_advlock },		/* advlock */
208 	{ &vop_bwrite_desc, ptyfs_bwrite },		/* bwrite */
209 	{ &vop_putpages_desc, ptyfs_putpages },		/* putpages */
210 	{ NULL, NULL }
211 };
212 const struct vnodeopv_desc ptyfs_vnodeop_opv_desc =
213 	{ &ptyfs_vnodeop_p, ptyfs_vnodeop_entries };
214 
215 /*
216  * 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_v2_args /* {
223 		struct vnode *a_vp;
224 	} */ *ap = v;
225 	struct vnode *vp = ap->a_vp;
226 
227 	VOP_UNLOCK(vp);
228 
229 	vp->v_data = NULL;
230 	return 0;
231 }
232 
233 int
234 ptyfs_inactive(void *v)
235 {
236 	struct vop_inactive_v2_args /* {
237 		struct vnode *a_vp;
238 		bool *a_recycle;
239 	} */ *ap = v;
240 	struct vnode *vp = ap->a_vp;
241 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
242 
243 	if (ptyfs->ptyfs_type == PTYFSptc)
244 		ptyfs_clr_active(vp->v_mount, ptyfs->ptyfs_pty);
245 
246 	return 0;
247 }
248 
249 /*
250  * Return POSIX pathconf information applicable to special devices.
251  */
252 int
253 ptyfs_pathconf(void *v)
254 {
255 	struct vop_pathconf_args /* {
256 		struct vnode *a_vp;
257 		int a_name;
258 		register_t *a_retval;
259 	} */ *ap = v;
260 
261 	switch (ap->a_name) {
262 	case _PC_LINK_MAX:
263 		*ap->a_retval = LINK_MAX;
264 		return 0;
265 	case _PC_MAX_CANON:
266 		*ap->a_retval = MAX_CANON;
267 		return 0;
268 	case _PC_MAX_INPUT:
269 		*ap->a_retval = MAX_INPUT;
270 		return 0;
271 	case _PC_PIPE_BUF:
272 		*ap->a_retval = PIPE_BUF;
273 		return 0;
274 	case _PC_CHOWN_RESTRICTED:
275 		*ap->a_retval = 1;
276 		return 0;
277 	case _PC_VDISABLE:
278 		*ap->a_retval = _POSIX_VDISABLE;
279 		return 0;
280 	case _PC_SYNC_IO:
281 		*ap->a_retval = 1;
282 		return 0;
283 	default:
284 		return EINVAL;
285 	}
286 }
287 
288 /*
289  * _print is used for debugging.
290  * just print a readable description
291  * of (vp).
292  */
293 int
294 ptyfs_print(void *v)
295 {
296 	struct vop_print_args /* {
297 		struct vnode *a_vp;
298 	} */ *ap = v;
299 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
300 
301 	printf("tag VT_PTYFS, type %d, pty %d\n",
302 	    ptyfs->ptyfs_type, ptyfs->ptyfs_pty);
303 	return 0;
304 }
305 
306 /*
307  * support advisory locking on pty nodes
308  */
309 int
310 ptyfs_advlock(void *v)
311 {
312 	struct vop_print_args /* {
313 		struct vnode *a_vp;
314 	} */ *ap = v;
315 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
316 
317 	switch (ptyfs->ptyfs_type) {
318 	case PTYFSpts:
319 	case PTYFSptc:
320 		return spec_advlock(v);
321 	default:
322 		return EOPNOTSUPP;
323 	}
324 }
325 
326 /*
327  * Invent attributes for ptyfsnode (vp) and store
328  * them in (vap).
329  * Directories lengths are returned as zero since
330  * any real length would require the genuine size
331  * to be computed, and nothing cares anyway.
332  *
333  * this is relatively minimal for ptyfs.
334  */
335 int
336 ptyfs_getattr(void *v)
337 {
338 	struct vop_getattr_args /* {
339 		struct vnode *a_vp;
340 		struct vattr *a_vap;
341 		kauth_cred_t a_cred;
342 	} */ *ap = v;
343 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
344 	struct vattr *vap = ap->a_vap;
345 
346 	PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
347 
348 	/* start by zeroing out the attributes */
349 	vattr_null(vap);
350 
351 	/* next do all the common fields */
352 	vap->va_type = ap->a_vp->v_type;
353 	vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0];
354 	vap->va_fileid = ptyfs->ptyfs_fileno;
355 	vap->va_gen = 0;
356 	vap->va_flags = 0;
357 	vap->va_blocksize = PAGE_SIZE;
358 
359 	vap->va_atime = ptyfs->ptyfs_atime;
360 	vap->va_mtime = ptyfs->ptyfs_mtime;
361 	vap->va_ctime = ptyfs->ptyfs_ctime;
362 	vap->va_birthtime = ptyfs->ptyfs_birthtime;
363 	vap->va_mode = ptyfs->ptyfs_mode;
364 	vap->va_flags = ptyfs->ptyfs_flags;
365 	vap->va_uid = ptyfs->ptyfs_uid;
366 	vap->va_gid = ptyfs->ptyfs_gid;
367 
368 	switch (ptyfs->ptyfs_type) {
369 	case PTYFSpts:
370 	case PTYFSptc:
371 		if (pty_isfree(ptyfs->ptyfs_pty, 1))
372 			return ENOENT;
373 		vap->va_bytes = vap->va_size = 0;
374 		vap->va_rdev = ap->a_vp->v_rdev;
375 		vap->va_nlink = 1;
376 		break;
377 	case PTYFSroot:
378 		vap->va_rdev = 0;
379 		vap->va_bytes = vap->va_size = DEV_BSIZE;
380 		vap->va_nlink = 2;
381 		break;
382 	default:
383 		return EOPNOTSUPP;
384 	}
385 
386 	return 0;
387 }
388 
389 /*ARGSUSED*/
390 int
391 ptyfs_setattr(void *v)
392 {
393 	struct vop_setattr_args /* {
394 		struct vnodeop_desc *a_desc;
395 		struct vnode *a_vp;
396 		struct vattr *a_vap;
397 		kauth_cred_t a_cred;
398 	} */ *ap = v;
399 	struct vnode *vp = ap->a_vp;
400 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
401 	struct vattr *vap = ap->a_vap;
402 	kauth_cred_t cred = ap->a_cred;
403 	struct lwp *l = curlwp;
404 	int error;
405 	kauth_action_t action = KAUTH_VNODE_WRITE_FLAGS;
406 	bool changing_sysflags = false;
407 
408 	if (vap->va_size != VNOVAL) {
409  		switch (ptyfs->ptyfs_type) {
410  		case PTYFSroot:
411  			return EISDIR;
412  		case PTYFSpts:
413  		case PTYFSptc:
414 			break;
415 		default:
416 			return EINVAL;
417 		}
418 	}
419 
420 	if (vap->va_flags != VNOVAL) {
421 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
422 			return EROFS;
423 
424 		/* Immutable and append-only flags are not supported on ptyfs. */
425 		if (vap->va_flags & (IMMUTABLE | APPEND))
426 			return EINVAL;
427 
428 		/* Snapshot flag cannot be set or cleared */
429 		if ((vap->va_flags & SF_SNAPSHOT) != (ptyfs->ptyfs_flags & SF_SNAPSHOT))
430 			return EPERM;
431 
432 		if ((ptyfs->ptyfs_flags & SF_SETTABLE) != (vap->va_flags & SF_SETTABLE)) {
433 			changing_sysflags = true;
434 			action |= KAUTH_VNODE_WRITE_SYSFLAGS;
435 		}
436 
437 		error = kauth_authorize_vnode(cred, action, vp, NULL,
438 		    genfs_can_chflags(cred, vp->v_type, ptyfs->ptyfs_uid,
439 		    changing_sysflags));
440 		if (error)
441 			return error;
442 
443 		if (changing_sysflags) {
444 			ptyfs->ptyfs_flags = vap->va_flags;
445 		} else {
446 			ptyfs->ptyfs_flags &= SF_SETTABLE;
447 			ptyfs->ptyfs_flags |= (vap->va_flags & UF_SETTABLE);
448 		}
449 		ptyfs->ptyfs_status |= PTYFS_CHANGE;
450 	}
451 
452 	/*
453 	 * Go through the fields and update iff not VNOVAL.
454 	 */
455 	if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
456 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
457 			return EROFS;
458 		if (ptyfs->ptyfs_type == PTYFSroot)
459 			return EPERM;
460 		error = ptyfs_chown(vp, vap->va_uid, vap->va_gid, cred, l);
461 		if (error)
462 			return error;
463 	}
464 
465 	if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL ||
466 	    vap->va_birthtime.tv_sec != VNOVAL) {
467 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
468 			return EROFS;
469 		if ((ptyfs->ptyfs_flags & SF_SNAPSHOT) != 0)
470 			return EPERM;
471 		error = kauth_authorize_vnode(cred, KAUTH_VNODE_WRITE_TIMES, vp,
472 		    NULL, genfs_can_chtimes(vp, vap->va_vaflags,
473 		    ptyfs->ptyfs_uid, cred));
474 		if (error)
475 			return (error);
476 		if (vap->va_atime.tv_sec != VNOVAL)
477 			if (!(vp->v_mount->mnt_flag & MNT_NOATIME))
478 				ptyfs->ptyfs_status |= PTYFS_ACCESS;
479 		if (vap->va_mtime.tv_sec != VNOVAL) {
480 			ptyfs->ptyfs_status |= PTYFS_CHANGE | PTYFS_MODIFY;
481 			if (vp->v_mount->mnt_flag & MNT_RELATIME)
482 				ptyfs->ptyfs_status |= PTYFS_ACCESS;
483 		}
484 		if (vap->va_birthtime.tv_sec != VNOVAL)
485 			ptyfs->ptyfs_birthtime = vap->va_birthtime;
486 		ptyfs->ptyfs_status |= PTYFS_CHANGE;
487 		error = ptyfs_update(vp, &vap->va_atime, &vap->va_mtime, 0);
488 		if (error)
489 			return error;
490 	}
491 	if (vap->va_mode != (mode_t)VNOVAL) {
492 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
493 			return EROFS;
494 		if (ptyfs->ptyfs_type == PTYFSroot)
495 			return EPERM;
496 		if ((ptyfs->ptyfs_flags & SF_SNAPSHOT) != 0 &&
497 		    (vap->va_mode &
498 		    (S_IXUSR|S_IWUSR|S_IXGRP|S_IWGRP|S_IXOTH|S_IWOTH)))
499 			return EPERM;
500 		error = ptyfs_chmod(vp, vap->va_mode, cred, l);
501 		if (error)
502 			return error;
503 	}
504 	VN_KNOTE(vp, NOTE_ATTRIB);
505 	return 0;
506 }
507 
508 /*
509  * Change the mode on a file.
510  * Inode must be locked before calling.
511  */
512 static int
513 ptyfs_chmod(struct vnode *vp, mode_t mode, kauth_cred_t cred, struct lwp *l)
514 {
515 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
516 	int error;
517 
518 	error = kauth_authorize_vnode(cred, KAUTH_VNODE_WRITE_SECURITY, vp,
519 	    NULL, genfs_can_chmod(vp->v_type, cred, ptyfs->ptyfs_uid,
520 	    ptyfs->ptyfs_gid, mode));
521 	if (error)
522 		return (error);
523 
524 	ptyfs->ptyfs_mode &= ~ALLPERMS;
525 	ptyfs->ptyfs_mode |= (mode & ALLPERMS);
526 	return 0;
527 }
528 
529 /*
530  * Perform chown operation on inode ip;
531  * inode must be locked prior to call.
532  */
533 static int
534 ptyfs_chown(struct vnode *vp, uid_t uid, gid_t gid, kauth_cred_t cred,
535     struct lwp *l)
536 {
537 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
538 	int error;
539 
540 	if (uid == (uid_t)VNOVAL)
541 		uid = ptyfs->ptyfs_uid;
542 	if (gid == (gid_t)VNOVAL)
543 		gid = ptyfs->ptyfs_gid;
544 
545 	error = kauth_authorize_vnode(cred, KAUTH_VNODE_CHANGE_OWNERSHIP, vp,
546 	    NULL, genfs_can_chown(cred, ptyfs->ptyfs_uid, ptyfs->ptyfs_gid,
547 	    uid, gid));
548 	if (error)
549 		return (error);
550 
551 	ptyfs->ptyfs_gid = gid;
552 	ptyfs->ptyfs_uid = uid;
553 	return 0;
554 }
555 
556 /*
557  * implement access checking.
558  *
559  * actually, the check for super-user is slightly
560  * broken since it will allow read access to write-only
561  * objects.  this doesn't cause any particular trouble
562  * but does mean that the i/o entry points need to check
563  * that the operation really does make sense.
564  */
565 int
566 ptyfs_access(void *v)
567 {
568 	struct vop_access_args /* {
569 		struct vnode *a_vp;
570 		int a_mode;
571 		kauth_cred_t a_cred;
572 	} */ *ap = v;
573 	struct vattr va;
574 	int error;
575 
576 	if ((error = VOP_GETATTR(ap->a_vp, &va, ap->a_cred)) != 0)
577 		return error;
578 
579 	return kauth_authorize_vnode(ap->a_cred,
580 	    KAUTH_ACCESS_ACTION(ap->a_mode, ap->a_vp->v_type, va.va_mode),
581 	    ap->a_vp, NULL, genfs_can_access(va.va_type, va.va_mode, va.va_uid,
582 	    va.va_gid, ap->a_mode, ap->a_cred));
583 }
584 
585 /*
586  * lookup.  this is incredibly complicated in the
587  * general case, however for most pseudo-filesystems
588  * very little needs to be done.
589  *
590  * Locking isn't hard here, just poorly documented.
591  *
592  * If we're looking up ".", just vref the parent & return it.
593  *
594  * If we're looking up "..", unlock the parent, and lock "..". If everything
595  * went ok, try to re-lock the parent. We do this to prevent lock races.
596  *
597  * For anything else, get the needed node.
598  *
599  * We try to exit with the parent locked in error cases.
600  */
601 int
602 ptyfs_lookup(void *v)
603 {
604 	struct vop_lookup_v2_args /* {
605 		struct vnode * a_dvp;
606 		struct vnode ** a_vpp;
607 		struct componentname * a_cnp;
608 	} */ *ap = v;
609 	struct componentname *cnp = ap->a_cnp;
610 	struct vnode **vpp = ap->a_vpp;
611 	struct vnode *dvp = ap->a_dvp;
612 	const char *pname = cnp->cn_nameptr;
613 	struct ptyfsnode *ptyfs;
614 	int pty, error;
615 
616 	*vpp = NULL;
617 
618 	if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
619 		return EROFS;
620 
621 	if (cnp->cn_namelen == 1 && *pname == '.') {
622 		*vpp = dvp;
623 		vref(dvp);
624 		return 0;
625 	}
626 
627 	ptyfs = VTOPTYFS(dvp);
628 	switch (ptyfs->ptyfs_type) {
629 	case PTYFSroot:
630 		/*
631 		 * Shouldn't get here with .. in the root node.
632 		 */
633 		if (cnp->cn_flags & ISDOTDOT)
634 			return EIO;
635 
636 		pty = atoi(pname, cnp->cn_namelen);
637 		if (pty < 0 || ptyfs_next_active(dvp->v_mount, pty) != pty)
638 			break;
639 		error = ptyfs_allocvp(dvp->v_mount, vpp, PTYFSpts, pty);
640 		if (error)
641 			return error;
642 		if (ptyfs_next_active(dvp->v_mount, pty) != pty) {
643 			vrele(*vpp);
644 			*vpp = NULL;
645 			return ENOENT;
646 		}
647 		return 0;
648 
649 	default:
650 		return ENOTDIR;
651 	}
652 
653 	return cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS;
654 }
655 
656 /*
657  * readdir returns directory entries from ptyfsnode (vp).
658  *
659  * the strategy here with ptyfs is to generate a single
660  * directory entry at a time (struct dirent) and then
661  * copy that out to userland using uiomove.  a more efficent
662  * though more complex implementation, would try to minimize
663  * the number of calls to uiomove().  for ptyfs, this is
664  * hardly worth the added code complexity.
665  *
666  * this should just be done through read()
667  */
668 int
669 ptyfs_readdir(void *v)
670 {
671 	struct vop_readdir_args /* {
672 		struct vnode *a_vp;
673 		struct uio *a_uio;
674 		kauth_cred_t a_cred;
675 		int *a_eofflag;
676 		off_t **a_cookies;
677 		int *a_ncookies;
678 	} */ *ap = v;
679 	struct uio *uio = ap->a_uio;
680 	struct dirent *dp;
681 	struct ptyfsnode *ptyfs;
682 	off_t i;
683 	int error;
684 	off_t *cookies = NULL;
685 	int ncookies;
686 	struct vnode *vp;
687 	int n, nc = 0;
688 
689 	vp = ap->a_vp;
690 	ptyfs = VTOPTYFS(vp);
691 
692 	if (uio->uio_resid < UIO_MX)
693 		return EINVAL;
694 	if (uio->uio_offset < 0)
695 		return EINVAL;
696 
697 	dp = malloc(sizeof(struct dirent), M_PTYFSTMP, M_WAITOK | M_ZERO);
698 
699 	error = 0;
700 	i = uio->uio_offset;
701 	dp->d_reclen = UIO_MX;
702 	ncookies = uio->uio_resid / UIO_MX;
703 
704 	if (ptyfs->ptyfs_type != PTYFSroot) {
705 		error = ENOTDIR;
706 		goto out;
707 	}
708 
709 	if (i >= npty)
710 		goto out;
711 
712 	if (ap->a_ncookies) {
713 		ncookies = min(ncookies, (npty + 2 - i));
714 		cookies = malloc(ncookies * sizeof (off_t),
715 		    M_TEMP, M_WAITOK);
716 		*ap->a_cookies = cookies;
717 	}
718 
719 	for (; i < 2; i++) {
720 		/* `.' and/or `..' */
721 		dp->d_fileno = PTYFS_FILENO(0, PTYFSroot);
722 		dp->d_namlen = i + 1;
723 		(void)memcpy(dp->d_name, "..", dp->d_namlen);
724 		dp->d_name[i + 1] = '\0';
725 		dp->d_type = DT_DIR;
726 		if ((error = uiomove(dp, UIO_MX, uio)) != 0)
727 			goto out;
728 		if (cookies)
729 			*cookies++ = i + 1;
730 		nc++;
731 	}
732 	while (uio->uio_resid >= UIO_MX) {
733 		/* check for used ptys */
734 		n = ptyfs_next_active(vp->v_mount, i - 2);
735 		if (n < 0)
736 			break;
737 		dp->d_fileno = PTYFS_FILENO(n, PTYFSpts);
738 		dp->d_namlen = snprintf(dp->d_name, sizeof(dp->d_name),
739 		    "%lld", (long long)(n));
740 		dp->d_type = DT_CHR;
741 		if ((error = uiomove(dp, UIO_MX, uio)) != 0)
742 			goto out;
743 		i = n + 3;
744 		if (cookies)
745 			*cookies++ = i;
746 		nc++;
747 	}
748 
749 out:
750 	/* not pertinent in error cases */
751 	ncookies = nc;
752 
753 	if (ap->a_ncookies) {
754 		if (error) {
755 			if (cookies)
756 				free(*ap->a_cookies, M_TEMP);
757 			*ap->a_ncookies = 0;
758 			*ap->a_cookies = NULL;
759 		} else
760 			*ap->a_ncookies = ncookies;
761 	}
762 	uio->uio_offset = i;
763 	free(dp, M_PTYFSTMP);
764 	return error;
765 }
766 
767 int
768 ptyfs_open(void *v)
769 {
770 	struct vop_open_args /* {
771 		struct vnode *a_vp;
772 		int  a_mode;
773 		kauth_cred_t a_cred;
774 	} */ *ap = v;
775 	struct vnode *vp = ap->a_vp;
776 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
777 
778 	switch (ptyfs->ptyfs_type) {
779 	case PTYFSpts:
780 	case PTYFSptc:
781 		return spec_open(v);
782 	case PTYFSroot:
783 		return 0;
784 	default:
785 		return EINVAL;
786 	}
787 }
788 
789 int
790 ptyfs_close(void *v)
791 {
792 	struct vop_close_args /* {
793 		struct vnode *a_vp;
794 		int  a_fflag;
795 		kauth_cred_t a_cred;
796 	} */ *ap = v;
797 	struct vnode *vp = ap->a_vp;
798 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
799 
800 	mutex_enter(vp->v_interlock);
801 	if (vp->v_usecount > 1)
802 		PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
803 	mutex_exit(vp->v_interlock);
804 
805 	switch (ptyfs->ptyfs_type) {
806 	case PTYFSpts:
807 	case PTYFSptc:
808 		return spec_close(v);
809 	case PTYFSroot:
810 		return 0;
811 	default:
812 		return EINVAL;
813 	}
814 }
815 
816 int
817 ptyfs_read(void *v)
818 {
819 	struct vop_read_args /* {
820 		struct vnode *a_vp;
821 		struct uio *a_uio;
822 		int  a_ioflag;
823 		kauth_cred_t a_cred;
824 	} */ *ap = v;
825 	struct timespec ts;
826 	struct vnode *vp = ap->a_vp;
827 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
828 	int error;
829 
830 	if (vp->v_type == VDIR)
831 		return EISDIR;
832 
833 	ptyfs->ptyfs_status |= PTYFS_ACCESS;
834 	/* hardclock() resolution is good enough for ptyfs */
835 	getnanotime(&ts);
836 	(void)ptyfs_update(vp, &ts, &ts, 0);
837 
838 	switch (ptyfs->ptyfs_type) {
839 	case PTYFSpts:
840 	case PTYFSptc:
841 		VOP_UNLOCK(vp);
842 		error = cdev_read(vp->v_rdev, ap->a_uio, ap->a_ioflag);
843 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
844 		return error;
845 	default:
846 		return EOPNOTSUPP;
847 	}
848 }
849 
850 int
851 ptyfs_write(void *v)
852 {
853 	struct vop_write_args /* {
854 		struct vnode *a_vp;
855 		struct uio *a_uio;
856 		int  a_ioflag;
857 		kauth_cred_t a_cred;
858 	} */ *ap = v;
859 	struct timespec ts;
860 	struct vnode *vp = ap->a_vp;
861 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
862 	int error;
863 
864 	ptyfs->ptyfs_status |= PTYFS_MODIFY;
865 	getnanotime(&ts);
866 	(void)ptyfs_update(vp, &ts, &ts, 0);
867 
868 	switch (ptyfs->ptyfs_type) {
869 	case PTYFSpts:
870 	case PTYFSptc:
871 		VOP_UNLOCK(vp);
872 		error = cdev_write(vp->v_rdev, ap->a_uio, ap->a_ioflag);
873 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
874 		return error;
875 	default:
876 		return EOPNOTSUPP;
877 	}
878 }
879 
880 int
881 ptyfs_ioctl(void *v)
882 {
883 	struct vop_ioctl_args /* {
884 		struct vnode *a_vp;
885 		u_long a_command;
886 		void *a_data;
887 		int  a_fflag;
888 		kauth_cred_t a_cred;
889 	} */ *ap = v;
890 	struct vnode *vp = ap->a_vp;
891 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
892 
893 	switch (ptyfs->ptyfs_type) {
894 	case PTYFSpts:
895 	case PTYFSptc:
896 		return cdev_ioctl(vp->v_rdev, ap->a_command,
897 		    ap->a_data, ap->a_fflag, curlwp);
898 	default:
899 		return EOPNOTSUPP;
900 	}
901 }
902 
903 int
904 ptyfs_poll(void *v)
905 {
906 	struct vop_poll_args /* {
907 		struct vnode *a_vp;
908 		int a_events;
909 	} */ *ap = v;
910 	struct vnode *vp = ap->a_vp;
911 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
912 
913 	switch (ptyfs->ptyfs_type) {
914 	case PTYFSpts:
915 	case PTYFSptc:
916 		return cdev_poll(vp->v_rdev, ap->a_events, curlwp);
917 	default:
918 		return genfs_poll(v);
919 	}
920 }
921 
922 int
923 ptyfs_kqfilter(void *v)
924 {
925 	struct vop_kqfilter_args /* {
926 		struct vnode *a_vp;
927 		struct knote *a_kn;
928 	} */ *ap = v;
929 	struct vnode *vp = ap->a_vp;
930 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
931 
932 	switch (ptyfs->ptyfs_type) {
933 	case PTYFSpts:
934 	case PTYFSptc:
935 		return cdev_kqfilter(vp->v_rdev, ap->a_kn);
936 	default:
937 		return genfs_kqfilter(v);
938 	}
939 }
940 
941 static int
942 ptyfs_update(struct vnode *vp, const struct timespec *acc,
943     const struct timespec *mod, int flags)
944 {
945 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
946 
947 	if (vp->v_mount->mnt_flag & MNT_RDONLY)
948 		return 0;
949 
950 	PTYFS_ITIMES(ptyfs, acc, mod, NULL);
951 	return 0;
952 }
953 
954 void
955 ptyfs_itimes(struct ptyfsnode *ptyfs, const struct timespec *acc,
956     const struct timespec *mod, const struct timespec *cre)
957 {
958 	struct timespec now;
959 
960 	KASSERT(ptyfs->ptyfs_status & (PTYFS_ACCESS|PTYFS_CHANGE|PTYFS_MODIFY));
961 
962 	getnanotime(&now);
963 	if (ptyfs->ptyfs_status & PTYFS_ACCESS) {
964 		if (acc == NULL)
965 			acc = &now;
966 		ptyfs->ptyfs_atime = *acc;
967 	}
968 	if (ptyfs->ptyfs_status & PTYFS_MODIFY) {
969 		if (mod == NULL)
970 			mod = &now;
971 		ptyfs->ptyfs_mtime = *mod;
972 	}
973 	if (ptyfs->ptyfs_status & PTYFS_CHANGE) {
974 		if (cre == NULL)
975 			cre = &now;
976 		ptyfs->ptyfs_ctime = *cre;
977 	}
978 	ptyfs->ptyfs_status &= ~(PTYFS_ACCESS|PTYFS_CHANGE|PTYFS_MODIFY);
979 }
980 
981 /*
982  * convert decimal ascii to int
983  */
984 static int
985 atoi(const char *b, size_t len)
986 {
987 	int p = 0;
988 
989 	while (len--) {
990 		char c = *b++;
991 		if (c < '0' || c > '9')
992 			return -1;
993 		p = 10 * p + (c - '0');
994 	}
995 
996 	return p;
997 }
998