xref: /freebsd/sys/fs/devfs/devfs_vnops.c (revision 7660b554bc59a07be0431c17e0e33815818baa69)
1 /*
2  * Copyright (c) 1992, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * Copyright (c) 2000
5  *	Poul-Henning Kamp.  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. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	@(#)kernfs_vnops.c	8.15 (Berkeley) 5/21/95
32  * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vnops.c 1.43
33  *
34  * $FreeBSD$
35  */
36 
37 /*
38  * TODO:
39  *	remove empty directories
40  *	mknod: hunt down DE_DELETED, compare name, reinstantiate.
41  *	mkdir: want it ?
42  */
43 
44 #include <opt_devfs.h>
45 #include <opt_mac.h>
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/conf.h>
50 #include <sys/dirent.h>
51 #include <sys/kernel.h>
52 #include <sys/lock.h>
53 #include <sys/mac.h>
54 #include <sys/malloc.h>
55 #include <sys/mount.h>
56 #include <sys/namei.h>
57 #include <sys/proc.h>
58 #include <sys/time.h>
59 #include <sys/unistd.h>
60 #include <sys/vnode.h>
61 
62 #include <fs/devfs/devfs.h>
63 
64 static int	devfs_access(struct vop_access_args *ap);
65 static int	devfs_getattr(struct vop_getattr_args *ap);
66 static int	devfs_ioctl(struct vop_ioctl_args *ap);
67 static int	devfs_lookupx(struct vop_lookup_args *ap);
68 static int	devfs_mknod(struct vop_mknod_args *ap);
69 static int	devfs_pathconf(struct vop_pathconf_args *ap);
70 static int	devfs_read(struct vop_read_args *ap);
71 static int	devfs_readdir(struct vop_readdir_args *ap);
72 static int	devfs_readlink(struct vop_readlink_args *ap);
73 static int	devfs_reclaim(struct vop_reclaim_args *ap);
74 static int	devfs_remove(struct vop_remove_args *ap);
75 static int	devfs_revoke(struct vop_revoke_args *ap);
76 static int	devfs_setattr(struct vop_setattr_args *ap);
77 #ifdef MAC
78 static int	devfs_setlabel(struct vop_setlabel_args *ap);
79 #endif
80 static int	devfs_symlink(struct vop_symlink_args *ap);
81 
82 static vop_t **devfs_vnodeop_p;
83 static vop_t **devfs_specop_p;
84 
85 /*
86  * Construct the fully qualified path name relative to the mountpoint
87  */
88 static char *
89 devfs_fqpn(char *buf, struct vnode *dvp, struct componentname *cnp)
90 {
91 	int i;
92 	struct devfs_dirent *de, *dd;
93 	struct devfs_mount *dmp;
94 
95 	dmp = VFSTODEVFS(dvp->v_mount);
96 	dd = dvp->v_data;
97 	i = SPECNAMELEN;
98 	buf[i] = '\0';
99 	i -= cnp->cn_namelen;
100 	if (i < 0)
101 		 return (NULL);
102 	bcopy(cnp->cn_nameptr, buf + i, cnp->cn_namelen);
103 	de = dd;
104 	while (de != dmp->dm_basedir) {
105 		i--;
106 		if (i < 0)
107 			 return (NULL);
108 		buf[i] = '/';
109 		i -= de->de_dirent->d_namlen;
110 		if (i < 0)
111 			 return (NULL);
112 		bcopy(de->de_dirent->d_name, buf + i,
113 		    de->de_dirent->d_namlen);
114 		de = TAILQ_FIRST(&de->de_dlist);	/* "." */
115 		de = TAILQ_NEXT(de, de_list);		/* ".." */
116 		de = de->de_dir;
117 	}
118 	return (buf + i);
119 }
120 
121 int
122 devfs_allocv(struct devfs_dirent *de, struct mount *mp, struct vnode **vpp, struct thread *td)
123 {
124 	int error;
125 	struct vnode *vp;
126 	dev_t dev;
127 
128 	if (td == NULL)
129 		td = curthread; /* XXX */
130 loop:
131 	vp = de->de_vnode;
132 	if (vp != NULL) {
133 		if (vget(vp, LK_EXCLUSIVE, td ? td : curthread))
134 			goto loop;
135 		*vpp = vp;
136 		return (0);
137 	}
138 	if (de->de_dirent->d_type == DT_CHR) {
139 		dev = *devfs_itod(de->de_inode);
140 		if (dev == NULL)
141 			return (ENOENT);
142 	} else {
143 		dev = NODEV;
144 	}
145 	error = getnewvnode("devfs", mp, devfs_vnodeop_p, &vp);
146 	if (error != 0) {
147 		printf("devfs_allocv: failed to allocate new vnode\n");
148 		return (error);
149 	}
150 
151 	if (de->de_dirent->d_type == DT_CHR) {
152 		vp->v_type = VCHR;
153 		vp = addaliasu(vp, dev->si_udev);
154 		vp->v_op = devfs_specop_p;
155 	} else if (de->de_dirent->d_type == DT_DIR) {
156 		vp->v_type = VDIR;
157 	} else if (de->de_dirent->d_type == DT_LNK) {
158 		vp->v_type = VLNK;
159 	} else {
160 		vp->v_type = VBAD;
161 	}
162 	vp->v_data = de;
163 	de->de_vnode = vp;
164 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
165 #ifdef MAC
166 	mac_associate_vnode_devfs(mp, de, vp);
167 #endif
168 	*vpp = vp;
169 	return (0);
170 }
171 
172 static int
173 devfs_access(ap)
174 	struct vop_access_args /* {
175 		struct vnode *a_vp;
176 		int  a_mode;
177 		struct ucred *a_cred;
178 		struct thread *a_td;
179 	} */ *ap;
180 {
181 	struct vnode *vp = ap->a_vp;
182 	struct devfs_dirent *de;
183 	int error;
184 
185 	de = vp->v_data;
186 	if (vp->v_type == VDIR)
187 		de = de->de_dir;
188 
189 	error = vaccess(vp->v_type, de->de_mode, de->de_uid, de->de_gid,
190 	    ap->a_mode, ap->a_cred, NULL);
191 	if (!error)
192 		return (error);
193 	if (error != EACCES)
194 		return (error);
195 	/* We do, however, allow access to the controlling terminal */
196 	if (!(ap->a_td->td_proc->p_flag & P_CONTROLT))
197 		return (error);
198 	if (ap->a_td->td_proc->p_session->s_ttyvp == de->de_vnode)
199 		return (0);
200 	return (error);
201 }
202 
203 static int
204 devfs_getattr(ap)
205 	struct vop_getattr_args /* {
206 		struct vnode *a_vp;
207 		struct vattr *a_vap;
208 		struct ucred *a_cred;
209 		struct thread *a_td;
210 	} */ *ap;
211 {
212 	struct vnode *vp = ap->a_vp;
213 	struct vattr *vap = ap->a_vap;
214 	int error = 0;
215 	struct devfs_dirent *de;
216 	dev_t dev;
217 
218 	de = vp->v_data;
219 	if (vp->v_type == VDIR)
220 		de = de->de_dir;
221 	bzero((caddr_t) vap, sizeof(*vap));
222 	vattr_null(vap);
223 	vap->va_uid = de->de_uid;
224 	vap->va_gid = de->de_gid;
225 	vap->va_mode = de->de_mode;
226 	if (vp->v_type == VLNK)
227 		vap->va_size = de->de_dirent->d_namlen;
228 	else if (vp->v_type == VDIR)
229 		vap->va_size = vap->va_bytes = DEV_BSIZE;
230 	else
231 		vap->va_size = 0;
232 	if (vp->v_type != VDIR)
233 		vap->va_bytes = 0;
234 	vap->va_blocksize = DEV_BSIZE;
235 	vap->va_type = vp->v_type;
236 
237 #define fix(aa)							\
238 	do {							\
239 		if ((aa).tv_sec == 0) {				\
240 			(aa).tv_sec = boottime.tv_sec;		\
241 			(aa).tv_nsec = boottime.tv_usec * 1000; \
242 		}						\
243 	} while (0)
244 
245 	if (vp->v_type != VCHR)  {
246 		fix(de->de_atime);
247 		vap->va_atime = de->de_atime;
248 		fix(de->de_mtime);
249 		vap->va_mtime = de->de_mtime;
250 		fix(de->de_ctime);
251 		vap->va_ctime = de->de_ctime;
252 	} else {
253 		dev = vp->v_rdev;
254 		fix(dev->si_atime);
255 		vap->va_atime = dev->si_atime;
256 		fix(dev->si_mtime);
257 		vap->va_mtime = dev->si_mtime;
258 		fix(dev->si_ctime);
259 		vap->va_ctime = dev->si_ctime;
260 		vap->va_rdev = dev->si_udev;
261 	}
262 	vap->va_gen = 0;
263 	vap->va_flags = 0;
264 	vap->va_nlink = de->de_links;
265 	vap->va_fileid = de->de_inode;
266 
267 	return (error);
268 }
269 
270 static int
271 devfs_ioctl(ap)
272 	struct vop_ioctl_args /* {
273 		struct vnode *a_vp;
274 		u_long  a_command;
275 		caddr_t  a_data;
276 		int  a_fflag;
277 		struct ucred *a_cred;
278 		struct thread *a_td;
279 	} */ *ap;
280 {
281 	int error;
282 
283 	error = devfs_rules_ioctl(ap->a_vp->v_mount, ap->a_command, ap->a_data,
284 	    ap->a_td);
285 	return (error);
286 }
287 
288 static int
289 devfs_lookupx(ap)
290 	struct vop_lookup_args /* {
291 		struct vnode * a_dvp;
292 		struct vnode ** a_vpp;
293 		struct componentname * a_cnp;
294 	} */ *ap;
295 {
296 	struct componentname *cnp;
297 	struct vnode *dvp, **vpp;
298 	struct thread *td;
299 	struct devfs_dirent *de, *dd;
300 	struct devfs_mount *dmp;
301 	dev_t cdev, *cpdev;
302 	int error, flags, nameiop;
303 	char specname[SPECNAMELEN + 1], *pname;
304 
305 	cnp = ap->a_cnp;
306 	vpp = ap->a_vpp;
307 	dvp = ap->a_dvp;
308 	pname = cnp->cn_nameptr;
309 	td = cnp->cn_thread;
310 	flags = cnp->cn_flags;
311 	nameiop = cnp->cn_nameiop;
312 	dmp = VFSTODEVFS(dvp->v_mount);
313 	dd = dvp->v_data;
314 
315 	*vpp = NULLVP;
316 	cnp->cn_flags &= ~PDIRUNLOCK;
317 
318 	if ((flags & ISLASTCN) && nameiop == RENAME)
319 		return (EOPNOTSUPP);
320 
321 	if (dvp->v_type != VDIR)
322 		return (ENOTDIR);
323 
324 	if ((flags & ISDOTDOT) && (dvp->v_vflag & VV_ROOT))
325 		return (EIO);
326 
327 	error = VOP_ACCESS(dvp, VEXEC, cnp->cn_cred, td);
328 	if (error)
329 		return (error);
330 
331 	if (cnp->cn_namelen == 1 && *pname == '.') {
332 		if ((flags & ISLASTCN) && nameiop != LOOKUP)
333 			return (EINVAL);
334 		*vpp = dvp;
335 		VREF(dvp);
336 		return (0);
337 	}
338 
339 	if (flags & ISDOTDOT) {
340 		if ((flags & ISLASTCN) && nameiop != LOOKUP)
341 			return (EINVAL);
342 		VOP_UNLOCK(dvp, 0, td);
343 		cnp->cn_flags |= PDIRUNLOCK;
344 		de = TAILQ_FIRST(&dd->de_dlist);	/* "." */
345 		de = TAILQ_NEXT(de, de_list);		/* ".." */
346 		de = de->de_dir;
347 		error = devfs_allocv(de, dvp->v_mount, vpp, td);
348 		if (error || ((flags & LOCKPARENT) && (flags & ISLASTCN))) {
349 			vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
350 			cnp->cn_flags &= ~PDIRUNLOCK;
351 		}
352 		return (error);
353 	}
354 
355 	devfs_populate(dmp);
356 	dd = dvp->v_data;
357 	TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
358 		if (cnp->cn_namelen != de->de_dirent->d_namlen)
359 			continue;
360 		if (bcmp(cnp->cn_nameptr, de->de_dirent->d_name,
361 		    de->de_dirent->d_namlen) != 0)
362 			continue;
363 		if (de->de_flags & DE_WHITEOUT)
364 			goto notfound;
365 		goto found;
366 	}
367 
368 	if (nameiop == DELETE)
369 		goto notfound;
370 
371 	/*
372 	 * OK, we didn't have an entry for the name we were asked for
373 	 * so we try to see if anybody can create it on demand.
374 	 */
375 	pname = devfs_fqpn(specname, dvp, cnp);
376 	if (pname == NULL)
377 		goto notfound;
378 
379 	cdev = NODEV;
380 	EVENTHANDLER_INVOKE(dev_clone, pname, strlen(pname), &cdev);
381 	if (cdev == NODEV)
382 		goto notfound;
383 
384 	devfs_populate(dmp);
385 	dd = dvp->v_data;
386 
387 	TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
388 		cpdev = devfs_itod(de->de_inode);
389 		if (cpdev != NULL && cdev == *cpdev)
390 			goto found;
391 		continue;
392 	}
393 
394 notfound:
395 
396 	if ((nameiop == CREATE || nameiop == RENAME) &&
397 	    (flags & (LOCKPARENT | WANTPARENT)) && (flags & ISLASTCN)) {
398 		cnp->cn_flags |= SAVENAME;
399 		if (!(flags & LOCKPARENT)) {
400 			VOP_UNLOCK(dvp, 0, td);
401 			cnp->cn_flags |= PDIRUNLOCK;
402 		}
403 		return (EJUSTRETURN);
404 	}
405 	return (ENOENT);
406 
407 
408 found:
409 
410 	if ((cnp->cn_nameiop == DELETE) && (flags & ISLASTCN)) {
411 		error = VOP_ACCESS(dvp, VWRITE, cnp->cn_cred, td);
412 		if (error)
413 			return (error);
414 		if (*vpp == dvp) {
415 			VREF(dvp);
416 			*vpp = dvp;
417 			return (0);
418 		}
419 		error = devfs_allocv(de, dvp->v_mount, vpp, td);
420 		if (error)
421 			return (error);
422 		if (!(flags & LOCKPARENT)) {
423 			VOP_UNLOCK(dvp, 0, td);
424 			cnp->cn_flags |= PDIRUNLOCK;
425 		}
426 		return (0);
427 	}
428 	error = devfs_allocv(de, dvp->v_mount, vpp, td);
429 	if (error)
430 		return (error);
431 	if (!(flags & LOCKPARENT) || !(flags & ISLASTCN)) {
432 		VOP_UNLOCK(dvp, 0, td);
433 		cnp->cn_flags |= PDIRUNLOCK;
434 	}
435 	return (0);
436 }
437 
438 static int
439 devfs_lookup(struct vop_lookup_args *ap)
440 {
441 	int j;
442 	struct devfs_mount *dmp;
443 
444 	dmp = VFSTODEVFS(ap->a_dvp->v_mount);
445 	lockmgr(&dmp->dm_lock, LK_SHARED, 0, curthread);
446 	j = devfs_lookupx(ap);
447 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curthread);
448 	return (j);
449 }
450 
451 static int
452 devfs_mknod(struct vop_mknod_args *ap)
453 /*
454 struct vop_mknod_args {
455 	struct vnodeop_desc *a_desc;
456 	struct vnode *a_dvp;
457 	struct vnode **a_vpp;
458 	struct componentname *a_cnp;
459 	struct vattr *a_vap;
460 };
461 */
462 {
463 	struct componentname *cnp;
464 	struct vnode *dvp, **vpp;
465 	struct thread *td;
466 	struct devfs_dirent *dd, *de;
467 	struct devfs_mount *dmp;
468 	int error;
469 
470 	dvp = ap->a_dvp;
471 	dmp = VFSTODEVFS(dvp->v_mount);
472 	lockmgr(&dmp->dm_lock, LK_EXCLUSIVE, 0, curthread);
473 
474 	cnp = ap->a_cnp;
475 	vpp = ap->a_vpp;
476 	td = cnp->cn_thread;
477 	dd = dvp->v_data;
478 
479 	error = ENOENT;
480 	TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
481 		if (cnp->cn_namelen != de->de_dirent->d_namlen)
482 			continue;
483 		if (bcmp(cnp->cn_nameptr, de->de_dirent->d_name,
484 		    de->de_dirent->d_namlen) != 0)
485 			continue;
486 		if (de->de_flags & DE_WHITEOUT)
487 			break;
488 		goto notfound;
489 	}
490 	if (de == NULL)
491 		goto notfound;
492 	de->de_flags &= ~DE_WHITEOUT;
493 	error = devfs_allocv(de, dvp->v_mount, vpp, td);
494 notfound:
495 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curthread);
496 	return (error);
497 }
498 
499 
500 static int
501 devfs_pathconf(ap)
502 	struct vop_pathconf_args /* {
503 		struct vnode *a_vp;
504 		int a_name;
505 		int *a_retval;
506 	} */ *ap;
507 {
508 
509 	switch (ap->a_name) {
510 	case _PC_NAME_MAX:
511 		*ap->a_retval = NAME_MAX;
512 		return (0);
513 	case _PC_PATH_MAX:
514 		*ap->a_retval = PATH_MAX;
515 		return (0);
516 	case _PC_MAC_PRESENT:
517 #ifdef MAC
518 		/*
519 		 * If MAC is enabled, devfs automatically supports
520 		 * trivial non-persistant label storage.
521 		 */
522 		*ap->a_retval = 1;
523 #else
524 		*ap->a_retval = 0;
525 #endif
526 		return (0);
527 	default:
528 		return (vop_stdpathconf(ap));
529 	}
530 	/* NOTREACHED */
531 }
532 
533 static int
534 devfs_read(ap)
535 	struct vop_read_args /* {
536 		struct vnode *a_vp;
537 		struct uio *a_uio;
538 		int a_ioflag;
539 		struct ucred *a_cred;
540 	} */ *ap;
541 {
542 
543 	if (ap->a_vp->v_type != VDIR)
544 		return (EINVAL);
545 	return (VOP_READDIR(ap->a_vp, ap->a_uio, ap->a_cred, NULL, NULL, NULL));
546 }
547 
548 static int
549 devfs_readdir(ap)
550 	struct vop_readdir_args /* {
551 		struct vnode *a_vp;
552 		struct uio *a_uio;
553 		struct ucred *a_cred;
554 		int *a_eofflag;
555 		int *a_ncookies;
556 		u_long **a_cookies;
557 	} */ *ap;
558 {
559 	int error;
560 	struct uio *uio;
561 	struct dirent *dp;
562 	struct devfs_dirent *dd;
563 	struct devfs_dirent *de;
564 	struct devfs_mount *dmp;
565 	off_t off, oldoff;
566 	int ncookies = 0;
567 	u_long *cookiebuf, *cookiep;
568 	struct dirent *dps, *dpe;
569 
570 	if (ap->a_vp->v_type != VDIR)
571 		return (ENOTDIR);
572 
573 	uio = ap->a_uio;
574 	if (uio->uio_offset < 0)
575 		return (EINVAL);
576 
577 	dmp = VFSTODEVFS(ap->a_vp->v_mount);
578 	lockmgr(&dmp->dm_lock, LK_SHARED, 0, curthread);
579 	devfs_populate(dmp);
580 	error = 0;
581 	de = ap->a_vp->v_data;
582 	off = 0;
583 	oldoff = uio->uio_offset;
584 	TAILQ_FOREACH(dd, &de->de_dlist, de_list) {
585 		if (dd->de_flags & DE_WHITEOUT)
586 			continue;
587 		if (dd->de_dirent->d_type == DT_DIR)
588 			de = dd->de_dir;
589 		else
590 			de = dd;
591 		dp = dd->de_dirent;
592 		if (dp->d_reclen > uio->uio_resid)
593 			break;
594 		dp->d_fileno = de->de_inode;
595 		if (off >= uio->uio_offset) {
596 			ncookies++;
597 			error = uiomove(dp, dp->d_reclen, uio);
598 			if (error)
599 				break;
600 		}
601 		off += dp->d_reclen;
602 	}
603 	if( !error && ap->a_ncookies != NULL && ap->a_cookies != NULL ) {
604 		MALLOC(cookiebuf, u_long *, ncookies * sizeof(u_long),
605 		       M_TEMP, M_WAITOK);
606 		cookiep = cookiebuf;
607 		dps = (struct dirent *)((char *)uio->uio_iov->iov_base -
608 		    (uio->uio_offset - oldoff));
609 		dpe = (struct dirent *) uio->uio_iov->iov_base;
610 		for( dp = dps;
611 			dp < dpe;
612 			dp = (struct dirent *)((caddr_t) dp + dp->d_reclen)) {
613 				oldoff += dp->d_reclen;
614 				*cookiep++ = (u_long) oldoff;
615 		}
616 		*ap->a_ncookies = ncookies;
617 		*ap->a_cookies = cookiebuf;
618 	}
619 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curthread);
620 	uio->uio_offset = off;
621 	return (error);
622 }
623 
624 static int
625 devfs_readlink(ap)
626 	struct vop_readlink_args /* {
627 		struct vnode *a_vp;
628 		struct uio *a_uio;
629 		struct ucred *a_cead;
630 	} */ *ap;
631 {
632 	int error;
633 	struct devfs_dirent *de;
634 
635 	de = ap->a_vp->v_data;
636 	error = uiomove(de->de_symlink, strlen(de->de_symlink), ap->a_uio);
637 	return (error);
638 }
639 
640 static int
641 devfs_reclaim(ap)
642 	struct vop_reclaim_args /* {
643 		struct vnode *a_vp;
644 	} */ *ap;
645 {
646 	struct vnode *vp = ap->a_vp;
647 	struct devfs_dirent *de;
648 	int i;
649 
650 	de = vp->v_data;
651 	if (de != NULL)
652 		de->de_vnode = NULL;
653 	vp->v_data = NULL;
654 	if (vp->v_rdev != NODEV && vp->v_rdev != NULL) {
655 		i = vcount(vp);
656 		if ((vp->v_rdev->si_flags & SI_CHEAPCLONE) && i == 0 &&
657 		    (vp->v_rdev->si_flags & SI_NAMED))
658 			destroy_dev(vp->v_rdev);
659 	}
660 	return (0);
661 }
662 
663 static int
664 devfs_remove(ap)
665 	struct vop_remove_args /* {
666 		struct vnode *a_dvp;
667 		struct vnode *a_vp;
668 		struct componentname *a_cnp;
669 	} */ *ap;
670 {
671 	struct vnode *vp = ap->a_vp;
672 	struct devfs_dirent *dd;
673 	struct devfs_dirent *de;
674 	struct devfs_mount *dmp = VFSTODEVFS(vp->v_mount);
675 
676 	lockmgr(&dmp->dm_lock, LK_EXCLUSIVE, 0, curthread);
677 	dd = ap->a_dvp->v_data;
678 	de = vp->v_data;
679 	if (de->de_dirent->d_type == DT_LNK) {
680 		TAILQ_REMOVE(&dd->de_dlist, de, de_list);
681 		if (de->de_vnode)
682 			de->de_vnode->v_data = NULL;
683 #ifdef MAC
684 		mac_destroy_devfsdirent(de);
685 #endif
686 		FREE(de, M_DEVFS);
687 	} else {
688 		de->de_flags |= DE_WHITEOUT;
689 	}
690 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curthread);
691 	return (0);
692 }
693 
694 /*
695  * Revoke is called on a tty when a terminal session ends.  The vnode
696  * is orphaned by setting v_op to deadfs so we need to let go of it
697  * as well so that we create a new one next time around.
698  */
699 static int
700 devfs_revoke(ap)
701 	struct vop_revoke_args /* {
702 		struct vnode *a_vp;
703 		int a_flags;
704 	} */ *ap;
705 {
706 	struct vnode *vp = ap->a_vp;
707 	struct devfs_dirent *de;
708 
709 	de = vp->v_data;
710 	de->de_vnode = NULL;
711 	vop_revoke(ap);
712 	return (0);
713 }
714 
715 static int
716 devfs_setattr(ap)
717 	struct vop_setattr_args /* {
718 		struct vnode *a_vp;
719 		struct vattr *a_vap;
720 		struct ucred *a_cred;
721 		struct proc *a_p;
722 	} */ *ap;
723 {
724 	struct devfs_dirent *de;
725 	struct vattr *vap;
726 	struct vnode *vp;
727 	int c, error;
728 	uid_t uid;
729 	gid_t gid;
730 
731 	vap = ap->a_vap;
732 	vp = ap->a_vp;
733 	if ((vap->va_type != VNON) ||
734 	    (vap->va_nlink != VNOVAL) ||
735 	    (vap->va_fsid != VNOVAL) ||
736 	    (vap->va_fileid != VNOVAL) ||
737 	    (vap->va_blocksize != VNOVAL) ||
738 	    (vap->va_flags != VNOVAL && vap->va_flags != 0) ||
739 	    (vap->va_rdev != VNOVAL) ||
740 	    ((int)vap->va_bytes != VNOVAL) ||
741 	    (vap->va_gen != VNOVAL)) {
742 		return (EINVAL);
743 	}
744 
745 	de = vp->v_data;
746 	if (vp->v_type == VDIR)
747 		de = de->de_dir;
748 
749 	error = c = 0;
750 	if (vap->va_uid == (uid_t)VNOVAL)
751 		uid = de->de_uid;
752 	else
753 		uid = vap->va_uid;
754 	if (vap->va_gid == (gid_t)VNOVAL)
755 		gid = de->de_gid;
756 	else
757 		gid = vap->va_gid;
758 	if (uid != de->de_uid || gid != de->de_gid) {
759 		if (((ap->a_cred->cr_uid != de->de_uid) || uid != de->de_uid ||
760 		    (gid != de->de_gid && !groupmember(gid, ap->a_cred))) &&
761 		    (error = suser_cred(ap->a_td->td_ucred, PRISON_ROOT)) != 0)
762 			return (error);
763 		de->de_uid = uid;
764 		de->de_gid = gid;
765 		c = 1;
766 	}
767 
768 	if (vap->va_mode != (mode_t)VNOVAL) {
769 		if ((ap->a_cred->cr_uid != de->de_uid) &&
770 		    (error = suser_cred(ap->a_td->td_ucred, PRISON_ROOT)))
771 			return (error);
772 		de->de_mode = vap->va_mode;
773 		c = 1;
774 	}
775 
776 	if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
777 		/* See the comment in ufs_vnops::ufs_setattr(). */
778 		if ((error = VOP_ACCESS(vp, VADMIN, ap->a_cred, ap->a_td)) &&
779 		    ((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
780 		    (error = VOP_ACCESS(vp, VWRITE, ap->a_cred, ap->a_td))))
781 			return (error);
782 		if (vap->va_atime.tv_sec != VNOVAL) {
783 			if (vp->v_type == VCHR)
784 				vp->v_rdev->si_atime = vap->va_atime;
785 			else
786 				de->de_atime = vap->va_atime;
787 		}
788 		if (vap->va_mtime.tv_sec != VNOVAL) {
789 			if (vp->v_type == VCHR)
790 				vp->v_rdev->si_mtime = vap->va_mtime;
791 			else
792 				de->de_mtime = vap->va_mtime;
793 		}
794 		c = 1;
795 	}
796 
797 	if (c) {
798 		if (vp->v_type == VCHR)
799 			vfs_timestamp(&vp->v_rdev->si_ctime);
800 		else
801 			vfs_timestamp(&de->de_mtime);
802 	}
803 	return (0);
804 }
805 
806 #ifdef MAC
807 static int
808 devfs_setlabel(ap)
809 	struct vop_setlabel_args /* {
810 		struct vnode *a_vp;
811 		struct mac *a_label;
812 		struct ucred *a_cred;
813 		struct thread *a_td;
814 	} */ *ap;
815 {
816 	struct vnode *vp;
817 	struct devfs_dirent *de;
818 
819 	vp = ap->a_vp;
820 	de = vp->v_data;
821 
822 	mac_relabel_vnode(ap->a_cred, vp, ap->a_label);
823 	mac_update_devfsdirent(vp->v_mount, de, vp);
824 
825 	return (0);
826 }
827 #endif
828 
829 static int
830 devfs_symlink(ap)
831 	struct vop_symlink_args /* {
832 		struct vnode *a_dvp;
833 		struct vnode **a_vpp;
834 		struct componentname *a_cnp;
835 		struct vattr *a_vap;
836 		char *a_target;
837 	} */ *ap;
838 {
839 	int i, error;
840 	struct devfs_dirent *dd;
841 	struct devfs_dirent *de;
842 	struct devfs_mount *dmp;
843 
844 	error = suser(ap->a_cnp->cn_thread);
845 	if (error)
846 		return(error);
847 	dmp = VFSTODEVFS(ap->a_dvp->v_mount);
848 	dd = ap->a_dvp->v_data;
849 	de = devfs_newdirent(ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen);
850 	de->de_uid = 0;
851 	de->de_gid = 0;
852 	de->de_mode = 0755;
853 	de->de_inode = dmp->dm_inode++;
854 	de->de_dirent->d_type = DT_LNK;
855 	i = strlen(ap->a_target) + 1;
856 	MALLOC(de->de_symlink, char *, i, M_DEVFS, M_WAITOK);
857 	bcopy(ap->a_target, de->de_symlink, i);
858 	lockmgr(&dmp->dm_lock, LK_EXCLUSIVE, 0, curthread);
859 #ifdef MAC
860 	mac_create_devfs_symlink(ap->a_cnp->cn_cred, dmp->dm_mount, dd, de);
861 #endif
862 	TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
863 	devfs_allocv(de, ap->a_dvp->v_mount, ap->a_vpp, 0);
864 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curthread);
865 	return (0);
866 }
867 
868 static struct vnodeopv_entry_desc devfs_vnodeop_entries[] = {
869 	{ &vop_default_desc,		(vop_t *) vop_defaultop },
870 	{ &vop_access_desc,		(vop_t *) devfs_access },
871 	{ &vop_getattr_desc,		(vop_t *) devfs_getattr },
872 	{ &vop_ioctl_desc,		(vop_t *) devfs_ioctl },
873 	{ &vop_lookup_desc,		(vop_t *) devfs_lookup },
874 	{ &vop_mknod_desc,		(vop_t *) devfs_mknod },
875 	{ &vop_pathconf_desc,		(vop_t *) devfs_pathconf },
876 	{ &vop_read_desc,		(vop_t *) devfs_read },
877 	{ &vop_readdir_desc,		(vop_t *) devfs_readdir },
878 	{ &vop_readlink_desc,		(vop_t *) devfs_readlink },
879 	{ &vop_reclaim_desc,		(vop_t *) devfs_reclaim },
880 	{ &vop_remove_desc,		(vop_t *) devfs_remove },
881 	{ &vop_revoke_desc,		(vop_t *) devfs_revoke },
882 	{ &vop_setattr_desc,		(vop_t *) devfs_setattr },
883 #ifdef MAC
884 	{ &vop_setlabel_desc,		(vop_t *) devfs_setlabel },
885 #endif
886 	{ &vop_symlink_desc,		(vop_t *) devfs_symlink },
887 	{ NULL, NULL }
888 };
889 static struct vnodeopv_desc devfs_vnodeop_opv_desc =
890 	{ &devfs_vnodeop_p, devfs_vnodeop_entries };
891 
892 VNODEOP_SET(devfs_vnodeop_opv_desc);
893 
894 static struct vnodeopv_entry_desc devfs_specop_entries[] = {
895 	{ &vop_default_desc,		(vop_t *) spec_vnoperate },
896 	{ &vop_access_desc,		(vop_t *) devfs_access },
897 	{ &vop_getattr_desc,		(vop_t *) devfs_getattr },
898 	{ &vop_pathconf_desc,		(vop_t *) devfs_pathconf },
899 	{ &vop_reclaim_desc,		(vop_t *) devfs_reclaim },
900 	{ &vop_remove_desc,		(vop_t *) devfs_remove },
901 	{ &vop_revoke_desc,		(vop_t *) devfs_revoke },
902 	{ &vop_setattr_desc,		(vop_t *) devfs_setattr },
903 #ifdef MAC
904 	{ &vop_setlabel_desc,		(vop_t *) devfs_setlabel },
905 #endif
906 	{ NULL, NULL }
907 };
908 static struct vnodeopv_desc devfs_specop_opv_desc =
909 	{ &devfs_specop_p, devfs_specop_entries };
910 
911 VNODEOP_SET(devfs_specop_opv_desc);
912