xref: /freebsd/sys/fs/devfs/devfs_vnops.c (revision ec09ef4ff8d0a377fd86c0c2e96a807a538fce4b)
1 #define DEBUG 1
2 /*
3  * Copyright (c) 1992, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  * Copyright (c) 2000
6  *	Poul-Henning Kamp.  All rights reserved.
7  *
8  * This code is derived from software donated to Berkeley by
9  * Jan-Simon Pendry.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  *	@(#)kernfs_vnops.c	8.15 (Berkeley) 5/21/95
33  * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vnops.c 1.43
34  *
35  * $FreeBSD$
36  */
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/conf.h>
41 #include <sys/dirent.h>
42 #include <sys/kernel.h>
43 #include <sys/lock.h>
44 #include <sys/malloc.h>
45 #include <sys/mount.h>
46 #include <sys/namei.h>
47 #include <sys/proc.h>
48 #include <sys/socket.h>
49 #include <sys/time.h>
50 #include <sys/vnode.h>
51 
52 #include <fs/devfs/devfs.h>
53 
54 static int	devfs_access __P((struct vop_access_args *ap));
55 static int	devfs_badop __P((void));
56 static int	devfs_getattr __P((struct vop_getattr_args *ap));
57 static int	devfs_lookupx __P((struct vop_lookup_args *ap));
58 static int	devfs_print __P((struct vop_print_args *ap));
59 static int	devfs_read __P((struct vop_read_args *ap));
60 static int	devfs_readdir __P((struct vop_readdir_args *ap));
61 static int	devfs_readlink __P((struct vop_readlink_args *ap));
62 static int	devfs_reclaim __P((struct vop_reclaim_args *ap));
63 static int	devfs_remove __P((struct vop_remove_args *ap));
64 static int	devfs_revoke __P((struct vop_revoke_args *ap));
65 static int	devfs_setattr __P((struct vop_setattr_args *ap));
66 static int	devfs_symlink __P((struct vop_symlink_args *ap));
67 
68 int
69 devfs_allocv(struct devfs_dirent *de, struct mount *mp, struct vnode **vpp, struct proc *p)
70 {
71 	int error;
72 	struct vnode *vp;
73 	dev_t dev;
74 
75 	if (p == NULL)
76 		p = curproc; /* XXX */
77 loop:
78 	vp = de->de_vnode;
79 	if (vp != NULL) {
80 		if (vget(vp, LK_EXCLUSIVE, p ? p : curproc))
81 			goto loop;
82 		*vpp = vp;
83 		return (0);
84 	}
85 	if (de->de_dirent->d_type == DT_CHR) {
86 		dev = *devfs_itod(de->de_inode);
87 		if (dev == NULL)
88 			return (ENOENT);
89 	} else {
90 		dev = NODEV;
91 	}
92 	error = getnewvnode(VT_DEVFS, mp, devfs_vnodeop_p, &vp);
93 	if (error != 0) {
94 		printf("devfs_allocv: failed to allocate new vnode\n");
95 		return (error);
96 	}
97 
98 	if (de->de_dirent->d_type == DT_CHR) {
99 		vp->v_type = VCHR;
100 		vp = addaliasu(vp, dev->si_udev);
101 		vp->v_op = devfs_specop_p;
102 	} else if (de->de_dirent->d_type == DT_DIR) {
103 		vp->v_type = VDIR;
104 	} else if (de->de_dirent->d_type == DT_LNK) {
105 		vp->v_type = VLNK;
106 	} else {
107 		vp->v_type = VBAD;
108 	}
109 	vp->v_data = de;
110 	de->de_vnode = vp;
111 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
112 	*vpp = vp;
113 	return (0);
114 }
115 
116 static int
117 devfs_access(ap)
118 	struct vop_access_args /* {
119 		struct vnode *a_vp;
120 		int  a_mode;
121 		struct ucred *a_cred;
122 		struct proc *a_p;
123 	} */ *ap;
124 {
125 	struct vnode *vp = ap->a_vp;
126 	struct devfs_dirent *de;
127 
128 	de = vp->v_data;
129 	if (vp->v_type == VDIR)
130 		de = de->de_dir;
131 
132 	return (vaccess(vp->v_type, de->de_mode, de->de_uid, de->de_gid,
133 	    ap->a_mode, ap->a_cred, NULL));
134 }
135 
136 static int
137 devfs_getattr(ap)
138 	struct vop_getattr_args /* {
139 		struct vnode *a_vp;
140 		struct vattr *a_vap;
141 		struct ucred *a_cred;
142 		struct proc *a_p;
143 	} */ *ap;
144 {
145 	struct vnode *vp = ap->a_vp;
146 	struct vattr *vap = ap->a_vap;
147 	int error = 0;
148 	struct devfs_dirent *de;
149 	dev_t dev;
150 
151 	de = vp->v_data;
152 	if (vp->v_type == VDIR)
153 		de = de->de_dir;
154 	bzero((caddr_t) vap, sizeof(*vap));
155 	vattr_null(vap);
156 	vap->va_uid = de->de_uid;
157 	vap->va_gid = de->de_gid;
158 	vap->va_mode = de->de_mode;
159 	if (vp->v_type == VLNK)
160 		vap->va_size = de->de_dirent->d_namlen;
161 	else
162 		vap->va_size = 0;
163 	vap->va_blocksize = DEV_BSIZE;
164 	vap->va_type = vp->v_type;
165 
166 #define fix(aa)							\
167 	do {							\
168 		if ((aa).tv_sec == 0) {				\
169 			(aa).tv_sec = boottime.tv_sec;		\
170 			(aa).tv_nsec = boottime.tv_usec * 1000; \
171 		}						\
172 	} while (0)
173 
174 	if (vp->v_type != VCHR)  {
175 		fix(de->de_atime);
176 		vap->va_atime = de->de_atime;
177 		fix(de->de_mtime);
178 		vap->va_mtime = de->de_mtime;
179 		fix(de->de_ctime);
180 		vap->va_ctime = de->de_ctime;
181 	} else {
182 		dev = vp->v_rdev;
183 		fix(dev->si_atime);
184 		vap->va_atime = dev->si_atime;
185 		fix(dev->si_mtime);
186 		vap->va_mtime = dev->si_mtime;
187 		fix(dev->si_ctime);
188 		vap->va_ctime = dev->si_ctime;
189 		vap->va_rdev = dev->si_udev;
190 	}
191 	vap->va_gen = 0;
192 	vap->va_flags = 0;
193 	vap->va_bytes = 0;
194 	vap->va_nlink = de->de_links;
195 	vap->va_fileid = de->de_inode;
196 
197 #ifdef DEBUG
198 	if (error)
199 		printf("devfs_getattr: return error %d\n", error);
200 #endif
201 	return (error);
202 }
203 
204 static int
205 devfs_lookupx(ap)
206 	struct vop_lookup_args /* {
207 		struct vnode * a_dvp;
208 		struct vnode ** a_vpp;
209 		struct componentname * a_cnp;
210 	} */ *ap;
211 {
212 	struct componentname *cnp;
213 	struct vnode *dvp, **vpp;
214 	struct proc *p;
215 	struct devfs_dirent *de, *dd;
216 	struct devfs_mount *dmp;
217 	dev_t cdev;
218 	int error, cloned, i, flags, nameiop;
219 	char specname[SPECNAMELEN + 1], *pname;
220 
221 	cnp = ap->a_cnp;
222 	vpp = ap->a_vpp;
223 	dvp = ap->a_dvp;
224 	pname = cnp->cn_nameptr;
225 	p = cnp->cn_proc;
226 	flags = cnp->cn_flags;
227 	nameiop = cnp->cn_nameiop;
228 	dmp = VFSTODEVFS(dvp->v_mount);
229 	cloned = 0;
230 	dd = dvp->v_data;
231 
232 	*vpp = NULLVP;
233 
234 	if (nameiop == RENAME)
235 		return (EOPNOTSUPP);
236 
237 	if (dvp->v_type != VDIR)
238 		return (ENOTDIR);
239 
240 	if ((flags & ISDOTDOT) && (dvp->v_flag & VROOT))
241 		return (EIO);
242 
243 	error = VOP_ACCESS(dvp, VEXEC, cnp->cn_cred, cnp->cn_proc);
244 	if (error)
245 		return (error);
246 
247 	if (cnp->cn_namelen == 1 && *pname == '.') {
248 		if (nameiop != LOOKUP)
249 			return (EINVAL);
250 		*vpp = dvp;
251 		VREF(dvp);
252 		return (0);
253 	}
254 
255 	if (flags & ISDOTDOT) {
256 		if (nameiop != LOOKUP)
257 			return (EINVAL);
258 		VOP_UNLOCK(dvp, 0, p);
259 		de = TAILQ_FIRST(&dd->de_dlist);	/* "." */
260 		de = TAILQ_NEXT(de, de_list);		/* ".." */
261 		de = de->de_dir;
262 		error = devfs_allocv(de, dvp->v_mount, vpp, p);
263 		if (error) {
264 			vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p);
265 			return (error);
266 		}
267 		if ((flags & LOCKPARENT) && (flags & ISLASTCN))
268 			error = vn_lock(dvp, LK_EXCLUSIVE, p);
269 		if (error)
270 			vput(*vpp);
271 		return (error);
272 	}
273 
274 	devfs_populate(dmp);
275 	dd = dvp->v_data;
276 	TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
277 		if (cnp->cn_namelen != de->de_dirent->d_namlen)
278 			continue;
279 		if (bcmp(cnp->cn_nameptr, de->de_dirent->d_name,
280 		    de->de_dirent->d_namlen) != 0)
281 			continue;
282 		goto found;
283 	}
284 
285 	/*
286 	 * OK, we didn't have an entry for the name we were asked for
287 	 * so we try to see if anybody can create it on demand.
288 	 * We need to construct the full "devname" for this device
289 	 * relative to "basedir" or the clone functions would not
290 	 * be able to tell "/dev/foo" from "/dev/bar/foo"
291 	 */
292 	i = SPECNAMELEN;
293 	specname[i] = '\0';
294 	i -= cnp->cn_namelen;
295 	if (i < 0)
296 		 goto notfound;
297 	bcopy(cnp->cn_nameptr, specname + i, cnp->cn_namelen);
298 	de = dd;
299 	while (de != dmp->dm_basedir) {
300 		i--;
301 		if (i < 0)
302 			 goto notfound;
303 		specname[i] = '/';
304 		i -= de->de_dirent->d_namlen;
305 		if (i < 0)
306 			 goto notfound;
307 		bcopy(de->de_dirent->d_name, specname + i,
308 		    de->de_dirent->d_namlen);
309 		de = TAILQ_FIRST(&de->de_dlist);	/* "." */
310 		de = TAILQ_NEXT(de, de_list);		/* ".." */
311 		de = de->de_dir;
312 	}
313 
314 #if 0
315 	printf("Finished specname: %d \"%s\"\n", i, specname + i);
316 #endif
317 	cdev = NODEV;
318 	EVENTHANDLER_INVOKE(dev_clone, specname + i,
319 	    strlen(specname + i), &cdev);
320 #if 0
321 	printf("cloned %s -> %p %s\n", specname + i, cdev,
322 	    cdev == NODEV ? "NODEV" : cdev->si_name);
323 #endif
324 	if (cdev == NODEV)
325 		goto notfound;
326 
327 	devfs_populate(dmp);
328 	dd = dvp->v_data;
329 	TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
330 		if (cnp->cn_namelen != de->de_dirent->d_namlen)
331 			continue;
332 		if (bcmp(cnp->cn_nameptr, de->de_dirent->d_name,
333 		    de->de_dirent->d_namlen) != 0)
334 			continue;
335 		goto found;
336 	}
337 
338 notfound:
339 
340 	if ((nameiop == CREATE || nameiop == RENAME) &&
341 	    (flags & (LOCKPARENT | WANTPARENT)) && (flags & ISLASTCN)) {
342 		cnp->cn_flags |= SAVENAME;
343 		if (!(flags & LOCKPARENT))
344 			VOP_UNLOCK(dvp, 0, p);
345 		return (EJUSTRETURN);
346 	}
347 	return (ENOENT);
348 
349 
350 found:
351 
352 	if ((cnp->cn_nameiop == DELETE) && (flags & ISLASTCN)) {
353 		error = VOP_ACCESS(dvp, VWRITE, cnp->cn_cred, p);
354 		if (error)
355 			return (error);
356 		if (*vpp == dvp) {
357 			VREF(dvp);
358 			*vpp = dvp;
359 			return (0);
360 		}
361 		error = devfs_allocv(de, dvp->v_mount, vpp, p);
362 		if (error)
363 			return (error);
364 		if (!(flags & LOCKPARENT))
365 			VOP_UNLOCK(dvp, 0, p);
366 		return (0);
367 	}
368 	error = devfs_allocv(de, dvp->v_mount, vpp, p);
369 	if (error)
370 		return (error);
371 	if (!(flags & LOCKPARENT) || !(flags & ISLASTCN))
372 		VOP_UNLOCK(dvp, 0, p);
373 	return (0);
374 }
375 
376 static int
377 devfs_lookup(struct vop_lookup_args *ap)
378 {
379 	int j;
380 	struct devfs_mount *dmp;
381 
382 	dmp = VFSTODEVFS(ap->a_dvp->v_mount);
383 	lockmgr(&dmp->dm_lock, LK_SHARED, 0, curproc);
384 	j = devfs_lookupx(ap);
385 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curproc);
386 	return (j);
387 }
388 
389 /* ARGSUSED */
390 static int
391 devfs_print(ap)
392 	struct vop_print_args /* {
393 		struct vnode *a_vp;
394 	} */ *ap;
395 {
396 
397 	printf("tag VT_DEVFS, devfs vnode\n");
398 	return (0);
399 }
400 
401 static int
402 devfs_read(ap)
403 	struct vop_read_args /* {
404 		struct vnode *a_vp;
405 		struct uio *a_uio;
406 		int a_ioflag;
407 		struct ucred *a_cred;
408 	} */ *ap;
409 {
410 
411 	if (ap->a_vp->v_type != VDIR)
412 		return (EINVAL);
413 	return (VOP_READDIR(ap->a_vp, ap->a_uio, ap->a_cred, NULL, NULL, NULL));
414 }
415 
416 static int
417 devfs_readdir(ap)
418 	struct vop_readdir_args /* {
419 		struct vnode *a_vp;
420 		struct uio *a_uio;
421 		struct ucred *a_cred;
422 		int *a_eofflag;
423 		int *a_ncookies;
424 		u_long **a_cookies;
425 	} */ *ap;
426 {
427 	int error;
428 	struct uio *uio;
429 	struct dirent *dp;
430 	struct devfs_dirent *dd;
431 	struct devfs_dirent *de;
432 	struct devfs_mount *dmp;
433 	off_t off;
434 
435 	if (ap->a_vp->v_type != VDIR)
436 		return (ENOTDIR);
437 
438 	if (ap->a_ncookies)
439 		return (EOPNOTSUPP);
440 
441 	uio = ap->a_uio;
442 	if (uio->uio_offset < 0)
443 		return (EINVAL);
444 
445 	dmp = VFSTODEVFS(ap->a_vp->v_mount);
446 	lockmgr(&dmp->dm_lock, LK_SHARED, 0, curproc);
447 	devfs_populate(dmp);
448 	error = 0;
449 	de = ap->a_vp->v_data;
450 	dd = TAILQ_FIRST(&de->de_dlist);
451 	off = 0;
452 	while (dd != NULL) {
453 		if (dd->de_dirent->d_type == DT_DIR)
454 			de = dd->de_dir;
455 		else
456 			de = dd;
457 		dp = dd->de_dirent;
458 		if (dp->d_reclen > uio->uio_resid)
459 			break;
460 		dp->d_fileno = de->de_inode;
461 		if (off >= uio->uio_offset) {
462 			error = uiomove((caddr_t)dp, dp->d_reclen, uio);
463 			if (error)
464 				break;
465 		}
466 		off += dp->d_reclen;
467 		dd = TAILQ_NEXT(dd, de_list);
468 	}
469 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curproc);
470 	uio->uio_offset = off;
471 	return (error);
472 }
473 
474 static int
475 devfs_readlink(ap)
476 	struct vop_readlink_args /* {
477 		struct vnode *a_vp;
478 		struct uio *a_uio;
479 		struct ucred *a_cead;
480 	} */ *ap;
481 {
482 	int error;
483 	struct devfs_dirent *de;
484 
485 	de = ap->a_vp->v_data;
486 	error = uiomove(de->de_symlink, strlen(de->de_symlink) + 1, ap->a_uio);
487 	return (error);
488 }
489 
490 static int
491 devfs_reclaim(ap)
492 	struct vop_reclaim_args /* {
493 		struct vnode *a_vp;
494 	} */ *ap;
495 {
496 	struct vnode *vp = ap->a_vp;
497 	struct devfs_dirent *de;
498 	int i;
499 
500 	de = vp->v_data;
501 	if (de != NULL)
502 		de->de_vnode = NULL;
503 	if (de != NULL && de->de_flags & DE_ORPHAN) {
504 		if (de->de_symlink)
505 			FREE(de->de_symlink, M_DEVFS);
506 		FREE(de, M_DEVFS);
507 	}
508 	vp->v_data = NULL;
509 	if (vp->v_rdev != NODEV && vp->v_rdev != NULL) {
510 		i = vcount(vp);
511 		if ((vp->v_rdev->si_flags & SI_CHEAPCLONE) && i == 0)
512 			destroy_dev(vp->v_rdev);
513 	}
514 	return (0);
515 }
516 
517 static int
518 devfs_remove(ap)
519 	struct vop_remove_args /* {
520 		struct vnode *a_dvp;
521 		struct vnode *a_vp;
522 		struct componentname *a_cnp;
523 	} */ *ap;
524 {
525 	struct vnode *vp = ap->a_vp;
526 	struct devfs_dirent *dd;
527 	struct devfs_dirent *de, **dep;
528 	struct devfs_mount *dmp = VFSTODEVFS(vp->v_mount);
529 
530 	lockmgr(&dmp->dm_lock, LK_EXCLUSIVE, 0, curproc);
531 	dd = ap->a_dvp->v_data;
532 	de = vp->v_data;
533 	TAILQ_REMOVE(&dd->de_dlist, de, de_list);
534 	dep = devfs_itode(dmp, de->de_inode);
535 	if (dep != NULL)
536 		*dep = DE_DELETED;
537 	de->de_flags |= DE_ORPHAN;
538 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curproc);
539 	return (0);
540 }
541 
542 /*
543  * Revoke is called on a tty when a terminal session ends.  The vnode
544  * is orphaned by setting v_op to deadfs so we need to let go of it
545  * as well so that we create a new one next time around.
546  */
547 static int
548 devfs_revoke(ap)
549 	struct vop_revoke_args /* {
550 		struct vnode *a_vp;
551 		int a_flags;
552 	} */ *ap;
553 {
554 	struct vnode *vp = ap->a_vp;
555 	struct devfs_dirent *de;
556 
557 	de = vp->v_data;
558 	de->de_vnode = NULL;
559 	vop_revoke(ap);
560 	return (0);
561 }
562 
563 static int
564 devfs_setattr(ap)
565 	struct vop_setattr_args /* {
566 		struct vnode *a_vp;
567 		struct vattr *a_vap;
568 		struct ucred *a_cred;
569 		struct proc *a_p;
570 	} */ *ap;
571 {
572 	struct devfs_dirent *de;
573 	struct vattr *vap;
574 	int c, error;
575 	uid_t uid;
576 	gid_t gid;
577 
578 	vap = ap->a_vap;
579 	if ((vap->va_type != VNON) ||
580 	    (vap->va_nlink != VNOVAL) ||
581 	    (vap->va_fsid != VNOVAL) ||
582 	    (vap->va_fileid != VNOVAL) ||
583 	    (vap->va_blocksize != VNOVAL) ||
584 	    (vap->va_flags != VNOVAL && vap->va_flags != 0) ||
585 	    (vap->va_rdev != VNOVAL) ||
586 	    ((int)vap->va_bytes != VNOVAL) ||
587 	    (vap->va_gen != VNOVAL)) {
588 		return (EINVAL);
589 	}
590 
591 	de = ap->a_vp->v_data;
592 	if (ap->a_vp->v_type == VDIR)
593 		de = de->de_dir;
594 
595 	error = c = 0;
596 	if (vap->va_uid == (uid_t)VNOVAL)
597 		uid = de->de_uid;
598 	else
599 		uid = vap->va_uid;
600 	if (vap->va_gid == (gid_t)VNOVAL)
601 		gid = de->de_gid;
602 	else
603 		gid = vap->va_gid;
604 	if (uid != de->de_uid || gid != de->de_gid) {
605 		if (((ap->a_cred->cr_uid != de->de_uid) || uid != de->de_uid ||
606 		    (gid != de->de_gid && !groupmember(gid, ap->a_cred))) &&
607 		    (error = suser(ap->a_p)) != 0)
608 			return (error);
609 		de->de_uid = uid;
610 		de->de_gid = gid;
611 		c = 1;
612 	}
613 	if (vap->va_mode != (mode_t)VNOVAL) {
614 		if ((ap->a_cred->cr_uid != de->de_uid) &&
615 		    (error = suser(ap->a_p)))
616 			return (error);
617 		de->de_mode = vap->va_mode;
618 		c = 1;
619 	}
620 	if (vap->va_atime.tv_sec != VNOVAL) {
621 		if ((ap->a_cred->cr_uid != de->de_uid) &&
622 		    (error = suser(ap->a_p)))
623 			return (error);
624 		de->de_atime = vap->va_atime;
625 		c = 1;
626 	}
627 	if (vap->va_mtime.tv_sec != VNOVAL) {
628 		if ((ap->a_cred->cr_uid != de->de_uid) &&
629 		    (error = suser(ap->a_p)))
630 			return (error);
631 		de->de_mtime = vap->va_mtime;
632 		c = 1;
633 	}
634 
635 	if (c)
636 		getnanotime(&de->de_ctime);
637 	return (0);
638 }
639 
640 static int
641 devfs_symlink(ap)
642 	struct vop_symlink_args /* {
643 		struct vnode *a_dvp;
644 		struct vnode **a_vpp;
645 		struct componentname *a_cnp;
646 		struct vattr *a_vap;
647 		char *a_target;
648 	} */ *ap;
649 {
650 	int i, error;
651 	struct devfs_dirent *dd;
652 	struct devfs_dirent *de;
653 	struct devfs_mount *dmp;
654 
655 	error = suser(ap->a_cnp->cn_proc);
656 	if (error)
657 		return(error);
658 	dmp = VFSTODEVFS(ap->a_dvp->v_mount);
659 	dd = ap->a_dvp->v_data;
660 	de = devfs_newdirent(ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen);
661 	de->de_uid = 0;
662 	de->de_gid = 0;
663 	de->de_mode = 0755;
664 	de->de_inode = dmp->dm_inode++;
665 	de->de_dirent->d_type = DT_LNK;
666 	i = strlen(ap->a_target) + 1;
667 	MALLOC(de->de_symlink, char *, i, M_DEVFS, M_WAITOK);
668 	bcopy(ap->a_target, de->de_symlink, i);
669 	lockmgr(&dmp->dm_lock, LK_EXCLUSIVE, 0, curproc);
670 	TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
671 	devfs_allocv(de, ap->a_dvp->v_mount, ap->a_vpp, 0);
672 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curproc);
673 	return (0);
674 }
675 
676 /*
677  * DEVFS "should never get here" operation
678  */
679 static int
680 devfs_badop()
681 {
682 	return (EIO);
683 }
684 
685 static vop_t **devfs_vnodeop_p;
686 static struct vnodeopv_entry_desc devfs_vnodeop_entries[] = {
687 	{ &vop_default_desc,		(vop_t *) vop_defaultop },
688 	{ &vop_access_desc,		(vop_t *) devfs_access },
689 	{ &vop_getattr_desc,		(vop_t *) devfs_getattr },
690 	{ &vop_lookup_desc,		(vop_t *) devfs_lookup },
691 	{ &vop_pathconf_desc,		(vop_t *) vop_stdpathconf },
692 	{ &vop_print_desc,		(vop_t *) devfs_print },
693 	{ &vop_read_desc,		(vop_t *) devfs_read },
694 	{ &vop_readdir_desc,		(vop_t *) devfs_readdir },
695 	{ &vop_readlink_desc,		(vop_t *) devfs_readlink },
696 	{ &vop_reclaim_desc,		(vop_t *) devfs_reclaim },
697 	{ &vop_remove_desc,		(vop_t *) devfs_remove },
698 	{ &vop_revoke_desc,		(vop_t *) devfs_revoke },
699 	{ &vop_setattr_desc,		(vop_t *) devfs_setattr },
700 	{ &vop_symlink_desc,		(vop_t *) devfs_symlink },
701 	{ NULL, NULL }
702 };
703 static struct vnodeopv_desc devfs_vnodeop_opv_desc =
704 	{ &devfs_vnodeop_p, devfs_vnodeop_entries };
705 
706 VNODEOP_SET(devfs_vnodeop_opv_desc);
707 
708 static vop_t **devfs_specop_p;
709 static struct vnodeopv_entry_desc devfs_specop_entries[] = {
710 	{ &vop_default_desc,		(vop_t *) spec_vnoperate },
711 	{ &vop_access_desc,		(vop_t *) devfs_access },
712 	{ &vop_getattr_desc,		(vop_t *) devfs_getattr },
713 	{ &vop_print_desc,		(vop_t *) devfs_print },
714 	{ &vop_reclaim_desc,		(vop_t *) devfs_reclaim },
715 	{ &vop_remove_desc,		(vop_t *) devfs_remove },
716 	{ &vop_revoke_desc,		(vop_t *) devfs_revoke },
717 	{ &vop_setattr_desc,		(vop_t *) devfs_setattr },
718 	{ NULL, NULL }
719 };
720 static struct vnodeopv_desc devfs_specop_opv_desc =
721 	{ &devfs_specop_p, devfs_specop_entries };
722 
723 VNODEOP_SET(devfs_specop_opv_desc);
724