xref: /freebsd/sys/fs/devfs/devfs_vnops.c (revision ebccf1e3a6b11b97cbf5f813dd76636e892a9035)
1 /*-
2  * Copyright (c) 2000-2004
3  *	Poul-Henning Kamp.  All rights reserved.
4  * Copyright (c) 1989, 1992-1993, 1995
5  *	The Regents of the University of California.  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/fcntl.h>
52 #include <sys/file.h>
53 #include <sys/filedesc.h>
54 #include <sys/filio.h>
55 #include <sys/kernel.h>
56 #include <sys/lock.h>
57 #include <sys/mac.h>
58 #include <sys/malloc.h>
59 #include <sys/mount.h>
60 #include <sys/namei.h>
61 #include <sys/proc.h>
62 #include <sys/stat.h>
63 #include <sys/sx.h>
64 #include <sys/sysctl.h>
65 #include <sys/time.h>
66 #include <sys/ttycom.h>
67 #include <sys/unistd.h>
68 #include <sys/vnode.h>
69 
70 #include <fs/devfs/devfs.h>
71 
72 static fo_rdwr_t	devfs_read_f;
73 static fo_rdwr_t	devfs_write_f;
74 static fo_ioctl_t	devfs_ioctl_f;
75 static fo_poll_t	devfs_poll_f;
76 static fo_kqfilter_t	devfs_kqfilter_f;
77 static fo_stat_t	devfs_stat_f;
78 static fo_close_t	devfs_close_f;
79 
80 static struct fileops devfs_ops_f = {
81 	.fo_read =	devfs_read_f,
82 	.fo_write =	devfs_write_f,
83 	.fo_ioctl =	devfs_ioctl_f,
84 	.fo_poll =	devfs_poll_f,
85 	.fo_kqfilter =	devfs_kqfilter_f,
86 	.fo_stat =	devfs_stat_f,
87 	.fo_close =	devfs_close_f,
88 	.fo_flags =	DFLAG_PASSABLE | DFLAG_SEEKABLE
89 };
90 
91 static vop_access_t	devfs_access;
92 static vop_advlock_t	devfs_advlock;
93 static vop_close_t	devfs_close;
94 static vop_fsync_t	devfs_fsync;
95 static vop_getattr_t	devfs_getattr;
96 static vop_lookup_t	devfs_lookupx;
97 static vop_mknod_t	devfs_mknod;
98 static vop_open_t	devfs_open;
99 static vop_pathconf_t	devfs_pathconf;
100 static vop_print_t	devfs_print;
101 static vop_readdir_t	devfs_readdir;
102 static vop_readlink_t	devfs_readlink;
103 static vop_reclaim_t	devfs_reclaim;
104 static vop_remove_t	devfs_remove;
105 static vop_revoke_t	devfs_revoke;
106 static vop_ioctl_t	devfs_rioctl;
107 static vop_read_t	devfs_rread;
108 static vop_setattr_t	devfs_setattr;
109 #ifdef MAC
110 static vop_setlabel_t	devfs_setlabel;
111 #endif
112 static vop_symlink_t	devfs_symlink;
113 
114 extern struct vop_vector devfs_vnodeops;
115 extern struct vop_vector devfs_specops;
116 
117 static u_int
118 devfs_random(void)
119 {
120 	static u_int devfs_seed;
121 
122 	while (devfs_seed == 0) {
123 		/*
124 		 * Make sure people don't make stupid assumptions
125 		 * about device major/minor numbers in userspace.
126 		 * We do this late to get entropy and for the same
127 		 * reason we force a reseed, but it may not be
128 		 * late enough for entropy to be available.
129 		 */
130 		arc4rand(&devfs_seed, sizeof devfs_seed, 1);
131 		devfs_seed &= 0xf0f;
132 	}
133 	return (devfs_seed);
134 }
135 
136 static int
137 devfs_fp_check(struct file *fp, struct cdev **devp, struct cdevsw **dswp)
138 {
139 
140 	*devp = fp->f_vnode->v_rdev;
141 	if (*devp != fp->f_data)
142 		return (ENXIO);
143 	KASSERT((*devp)->si_refcount > 0,
144 	    ("devfs: un-referenced struct cdev *(%s)", devtoname(*devp)));
145 	*dswp = dev_refthread(*devp);
146 	if (*dswp == NULL)
147 		return (ENXIO);
148 	return (0);
149 }
150 
151 /*
152  * Construct the fully qualified path name relative to the mountpoint
153  */
154 static char *
155 devfs_fqpn(char *buf, struct vnode *dvp, struct componentname *cnp)
156 {
157 	int i;
158 	struct devfs_dirent *de, *dd;
159 	struct devfs_mount *dmp;
160 
161 	dmp = VFSTODEVFS(dvp->v_mount);
162 	dd = dvp->v_data;
163 	i = SPECNAMELEN;
164 	buf[i] = '\0';
165 	i -= cnp->cn_namelen;
166 	if (i < 0)
167 		 return (NULL);
168 	bcopy(cnp->cn_nameptr, buf + i, cnp->cn_namelen);
169 	de = dd;
170 	while (de != dmp->dm_basedir) {
171 		i--;
172 		if (i < 0)
173 			 return (NULL);
174 		buf[i] = '/';
175 		i -= de->de_dirent->d_namlen;
176 		if (i < 0)
177 			 return (NULL);
178 		bcopy(de->de_dirent->d_name, buf + i,
179 		    de->de_dirent->d_namlen);
180 		de = TAILQ_FIRST(&de->de_dlist);	/* "." */
181 		de = TAILQ_NEXT(de, de_list);		/* ".." */
182 		de = de->de_dir;
183 	}
184 	return (buf + i);
185 }
186 
187 int
188 devfs_allocv(struct devfs_dirent *de, struct mount *mp, struct vnode **vpp, struct thread *td)
189 {
190 	int error;
191 	struct vnode *vp;
192 	struct cdev *dev;
193 
194 	KASSERT(td == curthread, ("devfs_allocv: td != curthread"));
195 loop:
196 	vp = de->de_vnode;
197 	if (vp != NULL) {
198 		if (vget(vp, LK_EXCLUSIVE, td))
199 			goto loop;
200 		*vpp = vp;
201 		return (0);
202 	}
203 	if (de->de_dirent->d_type == DT_CHR) {
204 		dev = *devfs_itod(de->de_inode);
205 		if (dev == NULL)
206 			return (ENOENT);
207 	} else {
208 		dev = NULL;
209 	}
210 	error = getnewvnode("devfs", mp, &devfs_vnodeops, &vp);
211 	if (error != 0) {
212 		printf("devfs_allocv: failed to allocate new vnode\n");
213 		return (error);
214 	}
215 
216 	if (de->de_dirent->d_type == DT_CHR) {
217 		vp->v_type = VCHR;
218 		VI_LOCK(vp);
219 		dev_lock();
220 		dev_refl(dev);
221 		vp->v_rdev = dev;
222 		LIST_INSERT_HEAD(&dev->si_alist, de, de_alias);
223 		dev->si_usecount += vp->v_usecount;
224 		dev_unlock();
225 		VI_UNLOCK(vp);
226 		vp->v_op = &devfs_specops;
227 	} else if (de->de_dirent->d_type == DT_DIR) {
228 		vp->v_type = VDIR;
229 	} else if (de->de_dirent->d_type == DT_LNK) {
230 		vp->v_type = VLNK;
231 	} else {
232 		vp->v_type = VBAD;
233 	}
234 	vp->v_data = de;
235 	de->de_vnode = vp;
236 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
237 #ifdef MAC
238 	mac_associate_vnode_devfs(mp, de, vp);
239 #endif
240 	*vpp = vp;
241 	return (0);
242 }
243 
244 static int
245 devfs_access(ap)
246 	struct vop_access_args /* {
247 		struct vnode *a_vp;
248 		int  a_mode;
249 		struct ucred *a_cred;
250 		struct thread *a_td;
251 	} */ *ap;
252 {
253 	struct vnode *vp = ap->a_vp;
254 	struct devfs_dirent *de;
255 	int error;
256 
257 	de = vp->v_data;
258 	if (vp->v_type == VDIR)
259 		de = de->de_dir;
260 
261 	error = vaccess(vp->v_type, de->de_mode, de->de_uid, de->de_gid,
262 	    ap->a_mode, ap->a_cred, NULL);
263 	if (!error)
264 		return (error);
265 	if (error != EACCES)
266 		return (error);
267 	/* We do, however, allow access to the controlling terminal */
268 	if (!(ap->a_td->td_proc->p_flag & P_CONTROLT))
269 		return (error);
270 	if (ap->a_td->td_proc->p_session->s_ttyvp == de->de_vnode)
271 		return (0);
272 	return (error);
273 }
274 
275 /*
276  * Special device advisory byte-level locks.
277  */
278 /* ARGSUSED */
279 static int
280 devfs_advlock(ap)
281 	struct vop_advlock_args /* {
282 		struct vnode *a_vp;
283 		caddr_t  a_id;
284 		int  a_op;
285 		struct flock *a_fl;
286 		int  a_flags;
287 	} */ *ap;
288 {
289 
290 	return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL);
291 }
292 
293 /*
294  * Device close routine
295  */
296 /* ARGSUSED */
297 static int
298 devfs_close(ap)
299 	struct vop_close_args /* {
300 		struct vnode *a_vp;
301 		int  a_fflag;
302 		struct ucred *a_cred;
303 		struct thread *a_td;
304 	} */ *ap;
305 {
306 	struct vnode *vp = ap->a_vp, *oldvp;
307 	struct thread *td = ap->a_td;
308 	struct cdev *dev = vp->v_rdev;
309 	struct cdevsw *dsw;
310 	int error;
311 
312 	/*
313 	 * Hack: a tty device that is a controlling terminal
314 	 * has a reference from the session structure.
315 	 * We cannot easily tell that a character device is
316 	 * a controlling terminal, unless it is the closing
317 	 * process' controlling terminal.  In that case,
318 	 * if the reference count is 2 (this last descriptor
319 	 * plus the session), release the reference from the session.
320 	 */
321 
322 	/*
323 	 * This needs to be rewritten to take the vp interlock into
324 	 * consideration.
325 	 */
326 
327 	oldvp = NULL;
328 	sx_xlock(&proctree_lock);
329 	if (td && vp == td->td_proc->p_session->s_ttyvp) {
330 		SESS_LOCK(td->td_proc->p_session);
331 		VI_LOCK(vp);
332 		if (count_dev(dev) == 2 && (vp->v_iflag & VI_DOOMED) == 0) {
333 			td->td_proc->p_session->s_ttyvp = NULL;
334 			oldvp = vp;
335 		}
336 		VI_UNLOCK(vp);
337 		SESS_UNLOCK(td->td_proc->p_session);
338 	}
339 	sx_xunlock(&proctree_lock);
340 	if (oldvp != NULL)
341 		vrele(oldvp);
342 	/*
343 	 * We do not want to really close the device if it
344 	 * is still in use unless we are trying to close it
345 	 * forcibly. Since every use (buffer, vnode, swap, cmap)
346 	 * holds a reference to the vnode, and because we mark
347 	 * any other vnodes that alias this device, when the
348 	 * sum of the reference counts on all the aliased
349 	 * vnodes descends to one, we are on last close.
350 	 */
351 	dsw = dev_refthread(dev);
352 	if (dsw == NULL)
353 		return (ENXIO);
354 	VI_LOCK(vp);
355 	if (vp->v_iflag & VI_DOOMED) {
356 		/* Forced close. */
357 	} else if (dsw->d_flags & D_TRACKCLOSE) {
358 		/* Keep device updated on status. */
359 	} else if (count_dev(dev) > 1) {
360 		VI_UNLOCK(vp);
361 		dev_relthread(dev);
362 		return (0);
363 	}
364 	VI_UNLOCK(vp);
365 	KASSERT(dev->si_refcount > 0,
366 	    ("devfs_close() on un-referenced struct cdev *(%s)", devtoname(dev)));
367 	if (!(dsw->d_flags & D_NEEDGIANT)) {
368 		DROP_GIANT();
369 		error = dsw->d_close(dev, ap->a_fflag, S_IFCHR, td);
370 		PICKUP_GIANT();
371 	} else
372 		error = dsw->d_close(dev, ap->a_fflag, S_IFCHR, td);
373 	dev_relthread(dev);
374 	return (error);
375 }
376 
377 static int
378 devfs_close_f(struct file *fp, struct thread *td)
379 {
380 
381 	return (vnops.fo_close(fp, td));
382 }
383 
384 /*
385  * Synch buffers associated with a block device
386  */
387 /* ARGSUSED */
388 static int
389 devfs_fsync(ap)
390 	struct vop_fsync_args /* {
391 		struct vnode *a_vp;
392 		struct ucred *a_cred;
393 		int  a_waitfor;
394 		struct thread *a_td;
395 	} */ *ap;
396 {
397 	if (!vn_isdisk(ap->a_vp, NULL))
398 		return (0);
399 
400 	return (vop_stdfsync(ap));
401 }
402 
403 static int
404 devfs_getattr(ap)
405 	struct vop_getattr_args /* {
406 		struct vnode *a_vp;
407 		struct vattr *a_vap;
408 		struct ucred *a_cred;
409 		struct thread *a_td;
410 	} */ *ap;
411 {
412 	struct vnode *vp = ap->a_vp;
413 	struct vattr *vap = ap->a_vap;
414 	int error = 0;
415 	struct devfs_dirent *de;
416 	struct cdev *dev;
417 
418 	de = vp->v_data;
419 	KASSERT(de != NULL, ("Null dirent in devfs_getattr vp=%p", vp));
420 	if (vp->v_type == VDIR) {
421 		de = de->de_dir;
422 		KASSERT(de != NULL,
423 		    ("Null dir dirent in devfs_getattr vp=%p", vp));
424 	}
425 	bzero((caddr_t) vap, sizeof(*vap));
426 	vattr_null(vap);
427 	vap->va_uid = de->de_uid;
428 	vap->va_gid = de->de_gid;
429 	vap->va_mode = de->de_mode;
430 	if (vp->v_type == VLNK)
431 		vap->va_size = strlen(de->de_symlink);
432 	else if (vp->v_type == VDIR)
433 		vap->va_size = vap->va_bytes = DEV_BSIZE;
434 	else
435 		vap->va_size = 0;
436 	if (vp->v_type != VDIR)
437 		vap->va_bytes = 0;
438 	vap->va_blocksize = DEV_BSIZE;
439 	vap->va_type = vp->v_type;
440 
441 #define fix(aa)							\
442 	do {							\
443 		if ((aa).tv_sec == 0) {				\
444 			(aa).tv_sec = boottime.tv_sec;		\
445 			(aa).tv_nsec = boottime.tv_usec * 1000; \
446 		}						\
447 	} while (0)
448 
449 	if (vp->v_type != VCHR)  {
450 		fix(de->de_atime);
451 		vap->va_atime = de->de_atime;
452 		fix(de->de_mtime);
453 		vap->va_mtime = de->de_mtime;
454 		fix(de->de_ctime);
455 		vap->va_ctime = de->de_ctime;
456 	} else {
457 		dev = vp->v_rdev;
458 		fix(dev->si_atime);
459 		vap->va_atime = dev->si_atime;
460 		fix(dev->si_mtime);
461 		vap->va_mtime = dev->si_mtime;
462 		fix(dev->si_ctime);
463 		vap->va_ctime = dev->si_ctime;
464 
465 		vap->va_rdev = dev->si_inode ^ devfs_random();
466 	}
467 	vap->va_gen = 0;
468 	vap->va_flags = 0;
469 	vap->va_nlink = de->de_links;
470 	vap->va_fileid = de->de_inode;
471 
472 	return (error);
473 }
474 
475 /*
476  * Device ioctl operation.
477  */
478 /* ARGSUSED */
479 static int
480 devfs_ioctl_f(struct file *fp, u_long com, void *data, struct ucred *cred, struct thread *td)
481 {
482 	struct cdev *dev;
483 	struct cdevsw *dsw;
484 	struct vnode *vp;
485 	struct vnode *vpold;
486 	int error, i;
487 	const char *p;
488 	struct fiodgname_arg *fgn;
489 
490 	error = devfs_fp_check(fp, &dev, &dsw);
491 	if (error)
492 		return (error);
493 
494 	if (com == FIODTYPE) {
495 		*(int *)data = dsw->d_flags & D_TYPEMASK;
496 		dev_relthread(dev);
497 		return (0);
498 	} else if (com == FIODGNAME) {
499 		fgn = data;
500 		p = devtoname(dev);
501 		i = strlen(p) + 1;
502 		if (i > fgn->len)
503 			return (EINVAL);
504 		return (copyout(p, fgn->buf, i));
505 	}
506 	if (dsw->d_flags & D_NEEDGIANT)
507 		mtx_lock(&Giant);
508 	error = dsw->d_ioctl(dev, com, data, fp->f_flag, td);
509 	if (dsw->d_flags & D_NEEDGIANT)
510 		mtx_unlock(&Giant);
511 	dev_relthread(dev);
512 	if (error == ENOIOCTL)
513 		error = ENOTTY;
514 	if (error == 0 && com == TIOCSCTTY) {
515 		vp = fp->f_vnode;
516 
517 		/* Do nothing if reassigning same control tty */
518 		sx_slock(&proctree_lock);
519 		if (td->td_proc->p_session->s_ttyvp == vp) {
520 			sx_sunlock(&proctree_lock);
521 			return (0);
522 		}
523 
524 		mtx_lock(&Giant);
525 
526 		vpold = td->td_proc->p_session->s_ttyvp;
527 		VREF(vp);
528 		SESS_LOCK(td->td_proc->p_session);
529 		td->td_proc->p_session->s_ttyvp = vp;
530 		SESS_UNLOCK(td->td_proc->p_session);
531 
532 		sx_sunlock(&proctree_lock);
533 
534 		/* Get rid of reference to old control tty */
535 		if (vpold)
536 			vrele(vpold);
537 		mtx_unlock(&Giant);
538 	}
539 	return (error);
540 }
541 
542 
543 /* ARGSUSED */
544 static int
545 devfs_kqfilter_f(struct file *fp, struct knote *kn)
546 {
547 	struct cdev *dev;
548 	struct cdevsw *dsw;
549 	int error;
550 
551 	error = devfs_fp_check(fp, &dev, &dsw);
552 	if (error)
553 		return (error);
554 	if (dsw->d_flags & D_NEEDGIANT)
555 		mtx_lock(&Giant);
556 	error = dsw->d_kqfilter(dev, kn);
557 	if (dsw->d_flags & D_NEEDGIANT)
558 		mtx_unlock(&Giant);
559 	dev_relthread(dev);
560 	return (error);
561 }
562 
563 static int
564 devfs_lookupx(ap)
565 	struct vop_lookup_args /* {
566 		struct vnode * a_dvp;
567 		struct vnode ** a_vpp;
568 		struct componentname * a_cnp;
569 	} */ *ap;
570 {
571 	struct componentname *cnp;
572 	struct vnode *dvp, **vpp;
573 	struct thread *td;
574 	struct devfs_dirent *de, *dd;
575 	struct devfs_dirent **dde;
576 	struct devfs_mount *dmp;
577 	struct cdev *cdev;
578 	int error, flags, nameiop;
579 	char specname[SPECNAMELEN + 1], *pname;
580 
581 	cnp = ap->a_cnp;
582 	vpp = ap->a_vpp;
583 	dvp = ap->a_dvp;
584 	pname = cnp->cn_nameptr;
585 	td = cnp->cn_thread;
586 	flags = cnp->cn_flags;
587 	nameiop = cnp->cn_nameiop;
588 	dmp = VFSTODEVFS(dvp->v_mount);
589 	dd = dvp->v_data;
590 	*vpp = NULLVP;
591 
592 	if ((flags & ISLASTCN) && nameiop == RENAME)
593 		return (EOPNOTSUPP);
594 
595 	if (dvp->v_type != VDIR)
596 		return (ENOTDIR);
597 
598 	if ((flags & ISDOTDOT) && (dvp->v_vflag & VV_ROOT))
599 		return (EIO);
600 
601 	error = VOP_ACCESS(dvp, VEXEC, cnp->cn_cred, td);
602 	if (error)
603 		return (error);
604 
605 	if (cnp->cn_namelen == 1 && *pname == '.') {
606 		if ((flags & ISLASTCN) && nameiop != LOOKUP)
607 			return (EINVAL);
608 		*vpp = dvp;
609 		VREF(dvp);
610 		return (0);
611 	}
612 
613 	if (flags & ISDOTDOT) {
614 		if ((flags & ISLASTCN) && nameiop != LOOKUP)
615 			return (EINVAL);
616 		VOP_UNLOCK(dvp, 0, td);
617 		de = TAILQ_FIRST(&dd->de_dlist);	/* "." */
618 		de = TAILQ_NEXT(de, de_list);		/* ".." */
619 		de = de->de_dir;
620 		error = devfs_allocv(de, dvp->v_mount, vpp, td);
621 		vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
622 		return (error);
623 	}
624 
625 	devfs_populate(dmp);
626 	dd = dvp->v_data;
627 	TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
628 		if (cnp->cn_namelen != de->de_dirent->d_namlen)
629 			continue;
630 		if (bcmp(cnp->cn_nameptr, de->de_dirent->d_name,
631 		    de->de_dirent->d_namlen) != 0)
632 			continue;
633 		if (de->de_flags & DE_WHITEOUT)
634 			goto notfound;
635 		goto found;
636 	}
637 
638 	if (nameiop == DELETE)
639 		goto notfound;
640 
641 	/*
642 	 * OK, we didn't have an entry for the name we were asked for
643 	 * so we try to see if anybody can create it on demand.
644 	 */
645 	pname = devfs_fqpn(specname, dvp, cnp);
646 	if (pname == NULL)
647 		goto notfound;
648 
649 	cdev = NULL;
650 	EVENTHANDLER_INVOKE(dev_clone, pname, strlen(pname), &cdev);
651 	if (cdev == NULL)
652 		goto notfound;
653 
654 	devfs_populate(dmp);
655 
656 	dde = devfs_itode(dmp, cdev->si_inode);
657 	dev_rel(cdev);
658 
659 	if (dde == NULL || *dde == NULL || *dde == DE_DELETED)
660 		goto notfound;
661 
662 	if ((*dde)->de_flags & DE_WHITEOUT)
663 		goto notfound;
664 
665 	de = *dde;
666 	goto found;
667 
668 notfound:
669 
670 	if ((nameiop == CREATE || nameiop == RENAME) &&
671 	    (flags & (LOCKPARENT | WANTPARENT)) && (flags & ISLASTCN)) {
672 		cnp->cn_flags |= SAVENAME;
673 		return (EJUSTRETURN);
674 	}
675 	return (ENOENT);
676 
677 
678 found:
679 
680 	if ((cnp->cn_nameiop == DELETE) && (flags & ISLASTCN)) {
681 		error = VOP_ACCESS(dvp, VWRITE, cnp->cn_cred, td);
682 		if (error)
683 			return (error);
684 		if (*vpp == dvp) {
685 			VREF(dvp);
686 			*vpp = dvp;
687 			return (0);
688 		}
689 		error = devfs_allocv(de, dvp->v_mount, vpp, td);
690 		if (error)
691 			return (error);
692 		return (0);
693 	}
694 	error = devfs_allocv(de, dvp->v_mount, vpp, td);
695 	return (error);
696 }
697 
698 static int
699 devfs_lookup(struct vop_lookup_args *ap)
700 {
701 	int j;
702 	struct devfs_mount *dmp;
703 
704 	dmp = VFSTODEVFS(ap->a_dvp->v_mount);
705 	lockmgr(&dmp->dm_lock, LK_SHARED, 0, curthread);
706 	j = devfs_lookupx(ap);
707 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curthread);
708 	return (j);
709 }
710 
711 static int
712 devfs_mknod(struct vop_mknod_args *ap)
713 	/*
714 	struct vop_mknod_args {
715 		struct vnodeop_desc *a_desc;
716 		struct vnode *a_dvp;
717 		struct vnode **a_vpp;
718 		struct componentname *a_cnp;
719 		struct vattr *a_vap;
720 	}; */
721 {
722 	struct componentname *cnp;
723 	struct vnode *dvp, **vpp;
724 	struct thread *td;
725 	struct devfs_dirent *dd, *de;
726 	struct devfs_mount *dmp;
727 	int error;
728 
729 	dvp = ap->a_dvp;
730 	dmp = VFSTODEVFS(dvp->v_mount);
731 	lockmgr(&dmp->dm_lock, LK_EXCLUSIVE, 0, curthread);
732 
733 	cnp = ap->a_cnp;
734 	vpp = ap->a_vpp;
735 	td = cnp->cn_thread;
736 	dd = dvp->v_data;
737 
738 	error = ENOENT;
739 	TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
740 		if (cnp->cn_namelen != de->de_dirent->d_namlen)
741 			continue;
742 		if (bcmp(cnp->cn_nameptr, de->de_dirent->d_name,
743 		    de->de_dirent->d_namlen) != 0)
744 			continue;
745 		if (de->de_flags & DE_WHITEOUT)
746 			break;
747 		goto notfound;
748 	}
749 	if (de == NULL)
750 		goto notfound;
751 	de->de_flags &= ~DE_WHITEOUT;
752 	error = devfs_allocv(de, dvp->v_mount, vpp, td);
753 notfound:
754 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curthread);
755 	return (error);
756 }
757 
758 /*
759  * Open a special file.
760  */
761 /* ARGSUSED */
762 static int
763 devfs_open(ap)
764 	struct vop_open_args /* {
765 		struct vnode *a_vp;
766 		int  a_mode;
767 		struct ucred *a_cred;
768 		struct thread *a_td;
769 		int a_fdidx;
770 	} */ *ap;
771 {
772 	struct thread *td = ap->a_td;
773 	struct vnode *vp = ap->a_vp;
774 	struct cdev *dev = vp->v_rdev;
775 	struct file *fp;
776 	int error;
777 	struct cdevsw *dsw;
778 
779 	if (vp->v_type == VBLK)
780 		return (ENXIO);
781 
782 	if (dev == NULL)
783 		return (ENXIO);
784 
785 	/* Make this field valid before any I/O in d_open. */
786 	if (dev->si_iosize_max == 0)
787 		dev->si_iosize_max = DFLTPHYS;
788 
789 	if (vn_isdisk(vp, NULL) &&
790 	    ap->a_cred != FSCRED && (ap->a_mode & FWRITE)) {
791 		/*
792 		* When running in very secure mode, do not allow
793 		* opens for writing of any disks.
794 		* XXX: should be in geom_dev.c, but we lack the cred there.
795 		*/
796 		error = securelevel_ge(td->td_ucred, 2);
797 		if (error)
798 			return (error);
799 	}
800 
801 	dsw = dev_refthread(dev);
802 	if (dsw == NULL)
803 		return (ENXIO);
804 
805 	/* XXX: Special casing of ttys for deadfs.  Probably redundant. */
806 	if (dsw->d_flags & D_TTY)
807 		vp->v_vflag |= VV_ISTTY;
808 
809 	VOP_UNLOCK(vp, 0, td);
810 
811 	if(!(dsw->d_flags & D_NEEDGIANT)) {
812 		DROP_GIANT();
813 		if (dsw->d_fdopen != NULL)
814 			error = dsw->d_fdopen(dev, ap->a_mode, td, ap->a_fdidx);
815 		else
816 			error = dsw->d_open(dev, ap->a_mode, S_IFCHR, td);
817 		PICKUP_GIANT();
818 	} else if (dsw->d_fdopen != NULL)
819 		error = dsw->d_fdopen(dev, ap->a_mode, td, ap->a_fdidx);
820 	else
821 		error = dsw->d_open(dev, ap->a_mode, S_IFCHR, td);
822 
823 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
824 
825 	dev_relthread(dev);
826 
827 	if (error)
828 		return (error);
829 
830 #if 0	/* /dev/console */
831 	KASSERT(ap->a_fdidx >= 0,
832 	     ("Could not vnode bypass device on fd %d", ap->a_fdidx));
833 #else
834 	if(ap->a_fdidx < 0)
835 		return (error);
836 #endif
837 	/*
838 	 * This is a pretty disgustingly long chain, but I am not
839 	 * sure there is any better way.  Passing the fdidx into
840 	 * VOP_OPEN() offers us more information than just passing
841 	 * the file *.
842 	 */
843 	fp = ap->a_td->td_proc->p_fd->fd_ofiles[ap->a_fdidx];
844 	KASSERT(fp->f_ops == &badfileops,
845 	     ("Could not vnode bypass device on fdops %p", fp->f_ops));
846 	fp->f_ops = &devfs_ops_f;
847 	fp->f_data = dev;
848 	return (error);
849 }
850 
851 static int
852 devfs_pathconf(ap)
853 	struct vop_pathconf_args /* {
854 		struct vnode *a_vp;
855 		int a_name;
856 		int *a_retval;
857 	} */ *ap;
858 {
859 
860 	switch (ap->a_name) {
861 	case _PC_NAME_MAX:
862 		*ap->a_retval = NAME_MAX;
863 		return (0);
864 	case _PC_PATH_MAX:
865 		*ap->a_retval = PATH_MAX;
866 		return (0);
867 	case _PC_MAC_PRESENT:
868 #ifdef MAC
869 		/*
870 		 * If MAC is enabled, devfs automatically supports
871 		 * trivial non-persistant label storage.
872 		 */
873 		*ap->a_retval = 1;
874 #else
875 		*ap->a_retval = 0;
876 #endif
877 		return (0);
878 	default:
879 		return (vop_stdpathconf(ap));
880 	}
881 	/* NOTREACHED */
882 }
883 
884 /* ARGSUSED */
885 static int
886 devfs_poll_f(struct file *fp, int events, struct ucred *cred, struct thread *td)
887 {
888 	struct cdev *dev;
889 	struct cdevsw *dsw;
890 	int error;
891 
892 	error = devfs_fp_check(fp, &dev, &dsw);
893 	if (error)
894 		return (error);
895 	if (dsw->d_flags & D_NEEDGIANT)
896 		mtx_lock(&Giant);
897 	error = dsw->d_poll(dev, events, td);
898 	if (dsw->d_flags & D_NEEDGIANT)
899 		mtx_unlock(&Giant);
900 	dev_relthread(dev);
901 	return(error);
902 }
903 
904 /*
905  * Print out the contents of a special device vnode.
906  */
907 static int
908 devfs_print(ap)
909 	struct vop_print_args /* {
910 		struct vnode *a_vp;
911 	} */ *ap;
912 {
913 
914 	printf("\tdev %s\n", devtoname(ap->a_vp->v_rdev));
915 	return (0);
916 }
917 
918 /*
919  * Vnode op for read
920  */
921 /* ARGSUSED */
922 static int
923 devfs_read_f(struct file *fp, struct uio *uio, struct ucred *cred, int flags, struct thread *td)
924 {
925 	struct cdev *dev;
926 	int ioflag, error, resid;
927 	struct cdevsw *dsw;
928 
929 	error = devfs_fp_check(fp, &dev, &dsw);
930 	if (error)
931 		return (error);
932 	resid = uio->uio_resid;
933 	ioflag = fp->f_flag & (O_NONBLOCK | O_DIRECT);
934 	if (ioflag & O_DIRECT)
935 		ioflag |= IO_DIRECT;
936 
937 	if ((flags & FOF_OFFSET) == 0)
938 		uio->uio_offset = fp->f_offset;
939 
940 	if (dsw->d_flags & D_NEEDGIANT)
941 		mtx_lock(&Giant);
942 	error = dsw->d_read(dev, uio, ioflag);
943 	if (dsw->d_flags & D_NEEDGIANT)
944 		mtx_unlock(&Giant);
945 	dev_relthread(dev);
946 	if (uio->uio_resid != resid || (error == 0 && resid != 0))
947 		vfs_timestamp(&dev->si_atime);
948 
949 	if ((flags & FOF_OFFSET) == 0)
950 		fp->f_offset = uio->uio_offset;
951 	fp->f_nextoff = uio->uio_offset;
952 	return (error);
953 }
954 
955 static int
956 devfs_readdir(ap)
957 	struct vop_readdir_args /* {
958 		struct vnode *a_vp;
959 		struct uio *a_uio;
960 		struct ucred *a_cred;
961 		int *a_eofflag;
962 		int *a_ncookies;
963 		u_long **a_cookies;
964 	} */ *ap;
965 {
966 	int error;
967 	struct uio *uio;
968 	struct dirent *dp;
969 	struct devfs_dirent *dd;
970 	struct devfs_dirent *de;
971 	struct devfs_mount *dmp;
972 	off_t off, oldoff;
973 	int ncookies = 0;
974 	u_long *cookiebuf, *cookiep;
975 	struct dirent *dps, *dpe;
976 
977 	if (ap->a_vp->v_type != VDIR)
978 		return (ENOTDIR);
979 
980 	uio = ap->a_uio;
981 	if (uio->uio_offset < 0)
982 		return (EINVAL);
983 
984 	dmp = VFSTODEVFS(ap->a_vp->v_mount);
985 	lockmgr(&dmp->dm_lock, LK_SHARED, 0, curthread);
986 	devfs_populate(dmp);
987 	error = 0;
988 	de = ap->a_vp->v_data;
989 	off = 0;
990 	oldoff = uio->uio_offset;
991 	TAILQ_FOREACH(dd, &de->de_dlist, de_list) {
992 		if (dd->de_flags & DE_WHITEOUT)
993 			continue;
994 		if (dd->de_dirent->d_type == DT_DIR)
995 			de = dd->de_dir;
996 		else
997 			de = dd;
998 		dp = dd->de_dirent;
999 		if (dp->d_reclen > uio->uio_resid)
1000 			break;
1001 		dp->d_fileno = de->de_inode;
1002 		if (off >= uio->uio_offset) {
1003 			ncookies++;
1004 			error = uiomove(dp, dp->d_reclen, uio);
1005 			if (error)
1006 				break;
1007 		}
1008 		off += dp->d_reclen;
1009 	}
1010 	if( !error && ap->a_ncookies != NULL && ap->a_cookies != NULL ) {
1011 		MALLOC(cookiebuf, u_long *, ncookies * sizeof(u_long),
1012 		       M_TEMP, M_WAITOK);
1013 		cookiep = cookiebuf;
1014 		dps = (struct dirent *)((char *)uio->uio_iov->iov_base -
1015 		    (uio->uio_offset - oldoff));
1016 		dpe = (struct dirent *) uio->uio_iov->iov_base;
1017 		for( dp = dps;
1018 			dp < dpe;
1019 			dp = (struct dirent *)((caddr_t) dp + dp->d_reclen)) {
1020 				oldoff += dp->d_reclen;
1021 				*cookiep++ = (u_long) oldoff;
1022 		}
1023 		*ap->a_ncookies = ncookies;
1024 		*ap->a_cookies = cookiebuf;
1025 	}
1026 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curthread);
1027 	uio->uio_offset = off;
1028 	return (error);
1029 }
1030 
1031 static int
1032 devfs_readlink(ap)
1033 	struct vop_readlink_args /* {
1034 		struct vnode *a_vp;
1035 		struct uio *a_uio;
1036 		struct ucred *a_cead;
1037 	} */ *ap;
1038 {
1039 	int error;
1040 	struct devfs_dirent *de;
1041 
1042 	de = ap->a_vp->v_data;
1043 	error = uiomove(de->de_symlink, strlen(de->de_symlink), ap->a_uio);
1044 	return (error);
1045 }
1046 
1047 static int
1048 devfs_reclaim(ap)
1049 	struct vop_reclaim_args /* {
1050 		struct vnode *a_vp;
1051 	} */ *ap;
1052 {
1053 	struct vnode *vp = ap->a_vp;
1054 	struct devfs_dirent *de;
1055 	struct cdev *dev;
1056 
1057 	de = vp->v_data;
1058 	if (de != NULL)
1059 		de->de_vnode = NULL;
1060 	vp->v_data = NULL;
1061 	vnode_destroy_vobject(vp);
1062 
1063 	dev = vp->v_rdev;
1064 	vp->v_rdev = NULL;
1065 
1066 	if (dev == NULL)
1067 		return (0);
1068 
1069 	dev_lock();
1070 	if (de != NULL)
1071 		LIST_REMOVE(de, de_alias);
1072 	dev->si_usecount -= vp->v_usecount;
1073 	dev_unlock();
1074 	dev_rel(dev);
1075 	return (0);
1076 }
1077 
1078 static int
1079 devfs_remove(ap)
1080 	struct vop_remove_args /* {
1081 		struct vnode *a_dvp;
1082 		struct vnode *a_vp;
1083 		struct componentname *a_cnp;
1084 	} */ *ap;
1085 {
1086 	struct vnode *vp = ap->a_vp;
1087 	struct devfs_dirent *dd;
1088 	struct devfs_dirent *de;
1089 	struct devfs_mount *dmp = VFSTODEVFS(vp->v_mount);
1090 
1091 	lockmgr(&dmp->dm_lock, LK_EXCLUSIVE, 0, curthread);
1092 	dd = ap->a_dvp->v_data;
1093 	de = vp->v_data;
1094 	if (de->de_dirent->d_type == DT_LNK) {
1095 		TAILQ_REMOVE(&dd->de_dlist, de, de_list);
1096 		if (de->de_vnode)
1097 			de->de_vnode->v_data = NULL;
1098 #ifdef MAC
1099 		mac_destroy_devfsdirent(de);
1100 #endif
1101 		FREE(de, M_DEVFS);
1102 	} else {
1103 		de->de_flags |= DE_WHITEOUT;
1104 	}
1105 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curthread);
1106 	return (0);
1107 }
1108 
1109 /*
1110  * Revoke is called on a tty when a terminal session ends.  The vnode
1111  * is orphaned by setting v_op to deadfs so we need to let go of it
1112  * as well so that we create a new one next time around.
1113  */
1114 static int
1115 devfs_revoke(ap)
1116 	struct vop_revoke_args /* {
1117 		struct vnode *a_vp;
1118 		int a_flags;
1119 	} */ *ap;
1120 {
1121 	struct vnode *vp = ap->a_vp;
1122 	struct cdev *dev;
1123 	struct devfs_dirent *de;
1124 
1125 	KASSERT((ap->a_flags & REVOKEALL) != 0, ("devfs_revoke !REVOKEALL"));
1126 
1127 	dev = vp->v_rdev;
1128 	for (;;) {
1129 		dev_lock();
1130 		de = LIST_FIRST(&dev->si_alist);
1131 		dev_unlock();
1132 		if (de == NULL)
1133 			break;
1134 		vgone(de->de_vnode);
1135 	}
1136 	return (0);
1137 }
1138 
1139 static int
1140 devfs_rioctl(ap)
1141 	struct vop_ioctl_args /* {
1142 		struct vnode *a_vp;
1143 		u_long  a_command;
1144 		caddr_t  a_data;
1145 		int  a_fflag;
1146 		struct ucred *a_cred;
1147 		struct thread *a_td;
1148 	} */ *ap;
1149 {
1150 	int error;
1151 	struct devfs_mount *dmp;
1152 
1153 	dmp = VFSTODEVFS(ap->a_vp->v_mount);
1154 	lockmgr(&dmp->dm_lock, LK_SHARED, 0, curthread);
1155 	devfs_populate(dmp);
1156 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curthread);
1157 	error = devfs_rules_ioctl(ap->a_vp->v_mount, ap->a_command, ap->a_data,
1158 	    ap->a_td);
1159 	return (error);
1160 }
1161 
1162 static int
1163 devfs_rread(ap)
1164 	struct vop_read_args /* {
1165 		struct vnode *a_vp;
1166 		struct uio *a_uio;
1167 		int a_ioflag;
1168 		struct ucred *a_cred;
1169 	} */ *ap;
1170 {
1171 
1172 	if (ap->a_vp->v_type != VDIR)
1173 		return (EINVAL);
1174 	return (VOP_READDIR(ap->a_vp, ap->a_uio, ap->a_cred, NULL, NULL, NULL));
1175 }
1176 
1177 static int
1178 devfs_setattr(ap)
1179 	struct vop_setattr_args /* {
1180 		struct vnode *a_vp;
1181 		struct vattr *a_vap;
1182 		struct ucred *a_cred;
1183 		struct proc *a_p;
1184 	} */ *ap;
1185 {
1186 	struct devfs_dirent *de;
1187 	struct vattr *vap;
1188 	struct vnode *vp;
1189 	int c, error;
1190 	uid_t uid;
1191 	gid_t gid;
1192 
1193 	vap = ap->a_vap;
1194 	vp = ap->a_vp;
1195 	if ((vap->va_type != VNON) ||
1196 	    (vap->va_nlink != VNOVAL) ||
1197 	    (vap->va_fsid != VNOVAL) ||
1198 	    (vap->va_fileid != VNOVAL) ||
1199 	    (vap->va_blocksize != VNOVAL) ||
1200 	    (vap->va_flags != VNOVAL && vap->va_flags != 0) ||
1201 	    (vap->va_rdev != VNOVAL) ||
1202 	    ((int)vap->va_bytes != VNOVAL) ||
1203 	    (vap->va_gen != VNOVAL)) {
1204 		return (EINVAL);
1205 	}
1206 
1207 	de = vp->v_data;
1208 	if (vp->v_type == VDIR)
1209 		de = de->de_dir;
1210 
1211 	error = c = 0;
1212 	if (vap->va_uid == (uid_t)VNOVAL)
1213 		uid = de->de_uid;
1214 	else
1215 		uid = vap->va_uid;
1216 	if (vap->va_gid == (gid_t)VNOVAL)
1217 		gid = de->de_gid;
1218 	else
1219 		gid = vap->va_gid;
1220 	if (uid != de->de_uid || gid != de->de_gid) {
1221 		if (((ap->a_cred->cr_uid != de->de_uid) || uid != de->de_uid ||
1222 		    (gid != de->de_gid && !groupmember(gid, ap->a_cred))) &&
1223 		    (error = suser_cred(ap->a_td->td_ucred, SUSER_ALLOWJAIL)) != 0)
1224 			return (error);
1225 		de->de_uid = uid;
1226 		de->de_gid = gid;
1227 		c = 1;
1228 	}
1229 
1230 	if (vap->va_mode != (mode_t)VNOVAL) {
1231 		if ((ap->a_cred->cr_uid != de->de_uid) &&
1232 		    (error = suser_cred(ap->a_td->td_ucred, SUSER_ALLOWJAIL)))
1233 			return (error);
1234 		de->de_mode = vap->va_mode;
1235 		c = 1;
1236 	}
1237 
1238 	if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
1239 		/* See the comment in ufs_vnops::ufs_setattr(). */
1240 		if ((error = VOP_ACCESS(vp, VADMIN, ap->a_cred, ap->a_td)) &&
1241 		    ((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
1242 		    (error = VOP_ACCESS(vp, VWRITE, ap->a_cred, ap->a_td))))
1243 			return (error);
1244 		if (vap->va_atime.tv_sec != VNOVAL) {
1245 			if (vp->v_type == VCHR)
1246 				vp->v_rdev->si_atime = vap->va_atime;
1247 			else
1248 				de->de_atime = vap->va_atime;
1249 		}
1250 		if (vap->va_mtime.tv_sec != VNOVAL) {
1251 			if (vp->v_type == VCHR)
1252 				vp->v_rdev->si_mtime = vap->va_mtime;
1253 			else
1254 				de->de_mtime = vap->va_mtime;
1255 		}
1256 		c = 1;
1257 	}
1258 
1259 	if (c) {
1260 		if (vp->v_type == VCHR)
1261 			vfs_timestamp(&vp->v_rdev->si_ctime);
1262 		else
1263 			vfs_timestamp(&de->de_mtime);
1264 	}
1265 	return (0);
1266 }
1267 
1268 #ifdef MAC
1269 static int
1270 devfs_setlabel(ap)
1271 	struct vop_setlabel_args /* {
1272 		struct vnode *a_vp;
1273 		struct mac *a_label;
1274 		struct ucred *a_cred;
1275 		struct thread *a_td;
1276 	} */ *ap;
1277 {
1278 	struct vnode *vp;
1279 	struct devfs_dirent *de;
1280 
1281 	vp = ap->a_vp;
1282 	de = vp->v_data;
1283 
1284 	mac_relabel_vnode(ap->a_cred, vp, ap->a_label);
1285 	mac_update_devfsdirent(vp->v_mount, de, vp);
1286 
1287 	return (0);
1288 }
1289 #endif
1290 
1291 static int
1292 devfs_stat_f(struct file *fp, struct stat *sb, struct ucred *cred, struct thread *td)
1293 {
1294 
1295 	return (vnops.fo_stat(fp, sb, cred, td));
1296 }
1297 
1298 static int
1299 devfs_symlink(ap)
1300 	struct vop_symlink_args /* {
1301 		struct vnode *a_dvp;
1302 		struct vnode **a_vpp;
1303 		struct componentname *a_cnp;
1304 		struct vattr *a_vap;
1305 		char *a_target;
1306 	} */ *ap;
1307 {
1308 	int i, error;
1309 	struct devfs_dirent *dd;
1310 	struct devfs_dirent *de;
1311 	struct devfs_mount *dmp;
1312 	struct thread *td;
1313 
1314 	td = ap->a_cnp->cn_thread;
1315 	KASSERT(td == curthread, ("devfs_symlink: td != curthread"));
1316 	error = suser(td);
1317 	if (error)
1318 		return(error);
1319 	dmp = VFSTODEVFS(ap->a_dvp->v_mount);
1320 	dd = ap->a_dvp->v_data;
1321 	de = devfs_newdirent(ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen);
1322 	de->de_uid = 0;
1323 	de->de_gid = 0;
1324 	de->de_mode = 0755;
1325 	de->de_inode = dmp->dm_inode++;
1326 	de->de_dirent->d_type = DT_LNK;
1327 	i = strlen(ap->a_target) + 1;
1328 	MALLOC(de->de_symlink, char *, i, M_DEVFS, M_WAITOK);
1329 	bcopy(ap->a_target, de->de_symlink, i);
1330 	lockmgr(&dmp->dm_lock, LK_EXCLUSIVE, 0, td);
1331 #ifdef MAC
1332 	mac_create_devfs_symlink(ap->a_cnp->cn_cred, dmp->dm_mount, dd, de);
1333 #endif
1334 	TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
1335 	devfs_allocv(de, ap->a_dvp->v_mount, ap->a_vpp, td);
1336 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, td);
1337 	return (0);
1338 }
1339 
1340 /*
1341  * Vnode op for write
1342  */
1343 /* ARGSUSED */
1344 static int
1345 devfs_write_f(struct file *fp, struct uio *uio, struct ucred *cred, int flags, struct thread *td)
1346 {
1347 	struct cdev *dev;
1348 	struct vnode *vp;
1349 	int error, ioflag, resid;
1350 	struct cdevsw *dsw;
1351 
1352 	error = devfs_fp_check(fp, &dev, &dsw);
1353 	if (error)
1354 		return (error);
1355 	KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", uio->uio_td, td));
1356 	vp = fp->f_vnode;
1357 	ioflag = fp->f_flag & (O_NONBLOCK | O_DIRECT | O_FSYNC);
1358 	if (ioflag & O_DIRECT)
1359 		ioflag |= IO_DIRECT;
1360 	if ((flags & FOF_OFFSET) == 0)
1361 		uio->uio_offset = fp->f_offset;
1362 
1363 	resid = uio->uio_resid;
1364 
1365 	if (dsw->d_flags & D_NEEDGIANT)
1366 		mtx_lock(&Giant);
1367 	error = dsw->d_write(dev, uio, ioflag);
1368 	if (dsw->d_flags & D_NEEDGIANT)
1369 		mtx_unlock(&Giant);
1370 	dev_relthread(dev);
1371 	if (uio->uio_resid != resid || (error == 0 && resid != 0)) {
1372 		vfs_timestamp(&dev->si_ctime);
1373 		dev->si_mtime = dev->si_ctime;
1374 	}
1375 
1376 	if ((flags & FOF_OFFSET) == 0)
1377 		fp->f_offset = uio->uio_offset;
1378 	fp->f_nextoff = uio->uio_offset;
1379 	return (error);
1380 }
1381 
1382 static struct vop_vector devfs_vnodeops = {
1383 	.vop_default =		&default_vnodeops,
1384 
1385 	.vop_access =		devfs_access,
1386 	.vop_getattr =		devfs_getattr,
1387 	.vop_ioctl =		devfs_rioctl,
1388 	.vop_lookup =		devfs_lookup,
1389 	.vop_mknod =		devfs_mknod,
1390 	.vop_pathconf =		devfs_pathconf,
1391 	.vop_read =		devfs_rread,
1392 	.vop_readdir =		devfs_readdir,
1393 	.vop_readlink =		devfs_readlink,
1394 	.vop_reclaim =		devfs_reclaim,
1395 	.vop_remove =		devfs_remove,
1396 	.vop_revoke =		devfs_revoke,
1397 	.vop_setattr =		devfs_setattr,
1398 #ifdef MAC
1399 	.vop_setlabel =		devfs_setlabel,
1400 #endif
1401 	.vop_symlink =		devfs_symlink,
1402 };
1403 
1404 static struct vop_vector devfs_specops = {
1405 	.vop_default =		&default_vnodeops,
1406 
1407 	.vop_access =		devfs_access,
1408 	.vop_advlock =		devfs_advlock,
1409 	.vop_bmap =		VOP_PANIC,
1410 	.vop_close =		devfs_close,
1411 	.vop_create =		VOP_PANIC,
1412 	.vop_fsync =		devfs_fsync,
1413 	.vop_getattr =		devfs_getattr,
1414 	.vop_lease =		VOP_NULL,
1415 	.vop_link =		VOP_PANIC,
1416 	.vop_mkdir =		VOP_PANIC,
1417 	.vop_mknod =		VOP_PANIC,
1418 	.vop_open =		devfs_open,
1419 	.vop_pathconf =		devfs_pathconf,
1420 	.vop_print =		devfs_print,
1421 	.vop_read =		VOP_PANIC,
1422 	.vop_readdir =		VOP_PANIC,
1423 	.vop_readlink =		VOP_PANIC,
1424 	.vop_reallocblks =	VOP_PANIC,
1425 	.vop_reclaim =		devfs_reclaim,
1426 	.vop_remove =		devfs_remove,
1427 	.vop_rename =		VOP_PANIC,
1428 	.vop_revoke =		devfs_revoke,
1429 	.vop_rmdir =		VOP_PANIC,
1430 	.vop_setattr =		devfs_setattr,
1431 #ifdef MAC
1432 	.vop_setlabel =		devfs_setlabel,
1433 #endif
1434 	.vop_strategy =		VOP_PANIC,
1435 	.vop_symlink =		VOP_PANIC,
1436 	.vop_write =		VOP_PANIC,
1437 };
1438 
1439 dev_t
1440 dev2udev(struct cdev *x)
1441 {
1442 	if (x == NULL)
1443 		return (NODEV);
1444 	return (x->si_inode ^ devfs_random());
1445 }
1446 
1447 /*
1448  * Helper sysctl for devname(3).  We're given a struct cdev * and return
1449  * the name, if any, registered by the device driver.
1450  */
1451 static int
1452 sysctl_devname(SYSCTL_HANDLER_ARGS)
1453 {
1454 	int error;
1455 	dev_t ud;
1456 	struct cdev *dev, **dp;
1457 
1458 	error = SYSCTL_IN(req, &ud, sizeof (ud));
1459 	if (error)
1460 		return (error);
1461 	if (ud == NODEV)
1462 		return(EINVAL);
1463 	dp = devfs_itod(ud ^ devfs_random());
1464 	if (dp == NULL)
1465 		return(ENOENT);
1466 	dev = *dp;
1467 	if (dev == NULL)
1468 		return(ENOENT);
1469 	return(SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1));
1470 	return (error);
1471 }
1472 
1473 SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
1474 	NULL, 0, sysctl_devname, "", "devname(3) handler");
1475 
1476 /*
1477  * Our calling convention to the device drivers used to be that we passed
1478  * vnode.h IO_* flags to read()/write(), but we're moving to fcntl.h O_
1479  * flags instead since that's what open(), close() and ioctl() takes and
1480  * we don't really want vnode.h in device drivers.
1481  * We solved the source compatibility by redefining some vnode flags to
1482  * be the same as the fcntl ones and by sending down the bitwise OR of
1483  * the respective fcntl/vnode flags.  These CTASSERTS make sure nobody
1484  * pulls the rug out under this.
1485  */
1486 CTASSERT(O_NONBLOCK == IO_NDELAY);
1487 CTASSERT(O_FSYNC == IO_SYNC);
1488