xref: /dragonfly/sys/kern/vfs_syscalls.c (revision fae225dc)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
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  *	@(#)vfs_syscalls.c	8.13 (Berkeley) 4/15/94
35  * $FreeBSD: src/sys/kern/vfs_syscalls.c,v 1.151.2.18 2003/04/04 20:35:58 tegge Exp $
36  */
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/buf.h>
41 #include <sys/conf.h>
42 #include <sys/sysent.h>
43 #include <sys/malloc.h>
44 #include <sys/mount.h>
45 #include <sys/mountctl.h>
46 #include <sys/sysproto.h>
47 #include <sys/filedesc.h>
48 #include <sys/kernel.h>
49 #include <sys/fcntl.h>
50 #include <sys/file.h>
51 #include <sys/linker.h>
52 #include <sys/stat.h>
53 #include <sys/unistd.h>
54 #include <sys/vnode.h>
55 #include <sys/proc.h>
56 #include <sys/priv.h>
57 #include <sys/jail.h>
58 #include <sys/namei.h>
59 #include <sys/nlookup.h>
60 #include <sys/dirent.h>
61 #include <sys/extattr.h>
62 #include <sys/spinlock.h>
63 #include <sys/kern_syscall.h>
64 #include <sys/objcache.h>
65 #include <sys/sysctl.h>
66 
67 #include <sys/buf2.h>
68 #include <sys/file2.h>
69 #include <sys/spinlock2.h>
70 
71 #include <vm/vm.h>
72 #include <vm/vm_object.h>
73 #include <vm/vm_page.h>
74 
75 #include <machine/limits.h>
76 #include <machine/stdarg.h>
77 
78 static void mount_warning(struct mount *mp, const char *ctl, ...)
79 		__printflike(2, 3);
80 static int mount_path(struct proc *p, struct mount *mp, char **rb, char **fb);
81 static int checkvp_chdir (struct vnode *vn, struct thread *td);
82 static void checkdirs (struct nchandle *old_nch, struct nchandle *new_nch);
83 static int chroot_refuse_vdir_fds (struct filedesc *fdp);
84 static int chroot_visible_mnt(struct mount *mp, struct proc *p);
85 static int getutimes (struct timeval *, struct timespec *);
86 static int getutimens (const struct timespec *, struct timespec *, int *);
87 static int setfown (struct mount *, struct vnode *, uid_t, gid_t);
88 static int setfmode (struct vnode *, int);
89 static int setfflags (struct vnode *, int);
90 static int setutimes (struct vnode *, struct vattr *,
91 			const struct timespec *, int);
92 static int	usermount = 0;	/* if 1, non-root can mount fs. */
93 
94 SYSCTL_INT(_vfs, OID_AUTO, usermount, CTLFLAG_RW, &usermount, 0,
95     "Allow non-root users to mount filesystems");
96 
97 /*
98  * Virtual File System System Calls
99  */
100 
101 /*
102  * Mount a file system.
103  *
104  * mount_args(char *type, char *path, int flags, caddr_t data)
105  *
106  * MPALMOSTSAFE
107  */
108 int
109 sys_mount(struct mount_args *uap)
110 {
111 	struct thread *td = curthread;
112 	struct vnode *vp;
113 	struct nchandle nch;
114 	struct mount *mp, *nullmp;
115 	struct vfsconf *vfsp;
116 	int error, flag = 0, flag2 = 0;
117 	int hasmount;
118 	struct vattr va;
119 	struct nlookupdata nd;
120 	char fstypename[MFSNAMELEN];
121 	struct ucred *cred;
122 
123 	cred = td->td_ucred;
124 	if (jailed(cred)) {
125 		error = EPERM;
126 		goto done;
127 	}
128 	if (usermount == 0 && (error = priv_check(td, PRIV_ROOT)))
129 		goto done;
130 
131 	/*
132 	 * Do not allow NFS export by non-root users.
133 	 */
134 	if (uap->flags & MNT_EXPORTED) {
135 		error = priv_check(td, PRIV_ROOT);
136 		if (error)
137 			goto done;
138 	}
139 	/*
140 	 * Silently enforce MNT_NOSUID and MNT_NODEV for non-root users
141 	 */
142 	if (priv_check(td, PRIV_ROOT))
143 		uap->flags |= MNT_NOSUID | MNT_NODEV;
144 
145 	/*
146 	 * Lookup the requested path and extract the nch and vnode.
147 	 */
148 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
149 	if (error == 0) {
150 		if ((error = nlookup(&nd)) == 0) {
151 			if (nd.nl_nch.ncp->nc_vp == NULL)
152 				error = ENOENT;
153 		}
154 	}
155 	if (error) {
156 		nlookup_done(&nd);
157 		goto done;
158 	}
159 
160 	/*
161 	 * If the target filesystem is resolved via a nullfs mount, then
162 	 * nd.nl_nch.mount will be pointing to the nullfs mount structure
163 	 * instead of the target file system. We need it in case we are
164 	 * doing an update.
165 	 */
166 	nullmp = nd.nl_nch.mount;
167 
168 	/*
169 	 * Extract the locked+refd ncp and cleanup the nd structure
170 	 */
171 	nch = nd.nl_nch;
172 	cache_zero(&nd.nl_nch);
173 	nlookup_done(&nd);
174 
175 	if ((nch.ncp->nc_flag & NCF_ISMOUNTPT) &&
176 	    (mp = cache_findmount(&nch)) != NULL) {
177 		cache_dropmount(mp);
178 		hasmount = 1;
179 	} else {
180 		hasmount = 0;
181 	}
182 
183 
184 	/*
185 	 * now we have the locked ref'd nch and unreferenced vnode.
186 	 */
187 	vp = nch.ncp->nc_vp;
188 	if ((error = vget(vp, LK_EXCLUSIVE)) != 0) {
189 		cache_put(&nch);
190 		goto done;
191 	}
192 	cache_unlock(&nch);
193 
194 	/*
195 	 * Extract the file system type. We need to know this early, to take
196 	 * appropriate actions if we are dealing with a nullfs.
197 	 */
198         if ((error = copyinstr(uap->type, fstypename, MFSNAMELEN, NULL)) != 0) {
199                 cache_drop(&nch);
200                 vput(vp);
201 		goto done;
202         }
203 
204 	/*
205 	 * Now we have an unlocked ref'd nch and a locked ref'd vp
206 	 */
207 	if (uap->flags & MNT_UPDATE) {
208 		if ((vp->v_flag & (VROOT|VPFSROOT)) == 0) {
209 			cache_drop(&nch);
210 			vput(vp);
211 			error = EINVAL;
212 			goto done;
213 		}
214 
215 		if (strncmp(fstypename, "null", 5) == 0) {
216 			KKASSERT(nullmp);
217 			mp = nullmp;
218 		} else {
219 			mp = vp->v_mount;
220 		}
221 
222 		flag = mp->mnt_flag;
223 		flag2 = mp->mnt_kern_flag;
224 		/*
225 		 * We only allow the filesystem to be reloaded if it
226 		 * is currently mounted read-only.
227 		 */
228 		if ((uap->flags & MNT_RELOAD) &&
229 		    ((mp->mnt_flag & MNT_RDONLY) == 0)) {
230 			cache_drop(&nch);
231 			vput(vp);
232 			error = EOPNOTSUPP;	/* Needs translation */
233 			goto done;
234 		}
235 		/*
236 		 * Only root, or the user that did the original mount is
237 		 * permitted to update it.
238 		 */
239 		if (mp->mnt_stat.f_owner != cred->cr_uid &&
240 		    (error = priv_check(td, PRIV_ROOT))) {
241 			cache_drop(&nch);
242 			vput(vp);
243 			goto done;
244 		}
245 		if (vfs_busy(mp, LK_NOWAIT)) {
246 			cache_drop(&nch);
247 			vput(vp);
248 			error = EBUSY;
249 			goto done;
250 		}
251 		if (hasmount) {
252 			cache_drop(&nch);
253 			vfs_unbusy(mp);
254 			vput(vp);
255 			error = EBUSY;
256 			goto done;
257 		}
258 		mp->mnt_flag |=
259 		    uap->flags & (MNT_RELOAD | MNT_FORCE | MNT_UPDATE);
260 		lwkt_gettoken(&mp->mnt_token);
261 		vn_unlock(vp);
262 		vfsp = mp->mnt_vfc;
263 		goto update;
264 	}
265 
266 	/*
267 	 * If the user is not root, ensure that they own the directory
268 	 * onto which we are attempting to mount.
269 	 */
270 	if ((error = VOP_GETATTR(vp, &va)) ||
271 	    (va.va_uid != cred->cr_uid &&
272 	     (error = priv_check(td, PRIV_ROOT)))) {
273 		cache_drop(&nch);
274 		vput(vp);
275 		goto done;
276 	}
277 	if ((error = vinvalbuf(vp, V_SAVE, 0, 0)) != 0) {
278 		cache_drop(&nch);
279 		vput(vp);
280 		goto done;
281 	}
282 	if (vp->v_type != VDIR) {
283 		cache_drop(&nch);
284 		vput(vp);
285 		error = ENOTDIR;
286 		goto done;
287 	}
288 	if (vp->v_mount->mnt_kern_flag & MNTK_NOSTKMNT) {
289 		cache_drop(&nch);
290 		vput(vp);
291 		error = EPERM;
292 		goto done;
293 	}
294 	vfsp = vfsconf_find_by_name(fstypename);
295 	if (vfsp == NULL) {
296 		linker_file_t lf;
297 
298 		/* Only load modules for root (very important!) */
299 		if ((error = priv_check(td, PRIV_ROOT)) != 0) {
300 			cache_drop(&nch);
301 			vput(vp);
302 			goto done;
303 		}
304 		error = linker_load_file(fstypename, &lf);
305 		if (error || lf == NULL) {
306 			cache_drop(&nch);
307 			vput(vp);
308 			if (lf == NULL)
309 				error = ENODEV;
310 			goto done;
311 		}
312 		lf->userrefs++;
313 		/* lookup again, see if the VFS was loaded */
314 		vfsp = vfsconf_find_by_name(fstypename);
315 		if (vfsp == NULL) {
316 			lf->userrefs--;
317 			linker_file_unload(lf);
318 			cache_drop(&nch);
319 			vput(vp);
320 			error = ENODEV;
321 			goto done;
322 		}
323 	}
324 	if (hasmount) {
325 		cache_drop(&nch);
326 		vput(vp);
327 		error = EBUSY;
328 		goto done;
329 	}
330 
331 	/*
332 	 * Allocate and initialize the filesystem.
333 	 */
334 	mp = kmalloc(sizeof(struct mount), M_MOUNT, M_ZERO|M_WAITOK);
335 	mount_init(mp);
336 	vfs_busy(mp, LK_NOWAIT);
337 	mp->mnt_op = vfsp->vfc_vfsops;
338 	mp->mnt_vfc = vfsp;
339 	mp->mnt_pbuf_count = nswbuf_kva / NSWBUF_SPLIT;
340 	vfsp->vfc_refcount++;
341 	mp->mnt_stat.f_type = vfsp->vfc_typenum;
342 	mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
343 	strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
344 	mp->mnt_stat.f_owner = cred->cr_uid;
345 	lwkt_gettoken(&mp->mnt_token);
346 	vn_unlock(vp);
347 update:
348 	/*
349 	 * (per-mount token acquired at this point)
350 	 *
351 	 * Set the mount level flags.
352 	 */
353 	if (uap->flags & MNT_RDONLY)
354 		mp->mnt_flag |= MNT_RDONLY;
355 	else if (mp->mnt_flag & MNT_RDONLY)
356 		mp->mnt_kern_flag |= MNTK_WANTRDWR;
357 	mp->mnt_flag &=~ (MNT_NOSUID | MNT_NOEXEC | MNT_NODEV |
358 	    MNT_SYNCHRONOUS | MNT_ASYNC | MNT_NOATIME |
359 	    MNT_NOSYMFOLLOW | MNT_IGNORE | MNT_TRIM |
360 	    MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR |
361 	    MNT_AUTOMOUNTED);
362 	mp->mnt_flag |= uap->flags & (MNT_NOSUID | MNT_NOEXEC |
363 	    MNT_NODEV | MNT_SYNCHRONOUS | MNT_ASYNC | MNT_FORCE |
364 	    MNT_NOSYMFOLLOW | MNT_IGNORE | MNT_TRIM |
365 	    MNT_NOATIME | MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR |
366 	    MNT_AUTOMOUNTED);
367 
368 	/*
369 	 * Pre-set the mount's ALL_MPSAFE flags if specified in the vfsconf.
370 	 * This way the initial VFS_MOUNT() call will also be MPSAFE.
371 	 */
372 	if (vfsp->vfc_flags & VFCF_MPSAFE)
373 		mp->mnt_kern_flag |= MNTK_ALL_MPSAFE;
374 
375 	/*
376 	 * Mount the filesystem.
377 	 * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
378 	 * get.
379 	 */
380 	error = VFS_MOUNT(mp, uap->path, uap->data, cred);
381 	if (mp->mnt_flag & MNT_UPDATE) {
382 		if (mp->mnt_kern_flag & MNTK_WANTRDWR)
383 			mp->mnt_flag &= ~MNT_RDONLY;
384 		mp->mnt_flag &=~ (MNT_UPDATE | MNT_RELOAD | MNT_FORCE);
385 		mp->mnt_kern_flag &=~ MNTK_WANTRDWR;
386 		if (error) {
387 			mp->mnt_flag = flag;
388 			mp->mnt_kern_flag = flag2;
389 		}
390 		lwkt_reltoken(&mp->mnt_token);
391 		vfs_unbusy(mp);
392 		vrele(vp);
393 		cache_drop(&nch);
394 		goto done;
395 	}
396 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
397 
398 	/*
399 	 * Put the new filesystem on the mount list after root.  The mount
400 	 * point gets its own mnt_ncmountpt (unless the VFS already set one
401 	 * up) which represents the root of the mount.  The lookup code
402 	 * detects the mount point going forward and checks the root of
403 	 * the mount going backwards.
404 	 *
405 	 * It is not necessary to invalidate or purge the vnode underneath
406 	 * because elements under the mount will be given their own glue
407 	 * namecache record.
408 	 */
409 	if (!error) {
410 		if (mp->mnt_ncmountpt.ncp == NULL) {
411 			/*
412 			 * Allocate, then unlock, but leave the ref intact.
413 			 * This is the mnt_refs (1) that we will retain
414 			 * through to the unmount.
415 			 */
416 			cache_allocroot(&mp->mnt_ncmountpt, mp, NULL);
417 			cache_unlock(&mp->mnt_ncmountpt);
418 		}
419 		vn_unlock(vp);
420 		mp->mnt_ncmounton = nch;		/* inherits ref */
421 		cache_lock(&nch);
422 		nch.ncp->nc_flag |= NCF_ISMOUNTPT;
423 		cache_unlock(&nch);
424 		cache_ismounting(mp);
425 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
426 
427 		mountlist_insert(mp, MNTINS_LAST);
428 		vn_unlock(vp);
429 		checkdirs(&mp->mnt_ncmounton, &mp->mnt_ncmountpt);
430 		error = vfs_allocate_syncvnode(mp);
431 		lwkt_reltoken(&mp->mnt_token);
432 		vfs_unbusy(mp);
433 		error = VFS_START(mp, 0);
434 		vrele(vp);
435 		KNOTE(&fs_klist, VQ_MOUNT);
436 	} else {
437 		vn_syncer_thr_stop(mp);
438 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
439 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
440 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
441 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
442 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
443 		mp->mnt_vfc->vfc_refcount--;
444 		lwkt_reltoken(&mp->mnt_token);
445 		vfs_unbusy(mp);
446 		kfree(mp, M_MOUNT);
447 		cache_drop(&nch);
448 		vput(vp);
449 	}
450 done:
451 	return (error);
452 }
453 
454 /*
455  * Scan all active processes to see if any of them have a current
456  * or root directory onto which the new filesystem has just been
457  * mounted. If so, replace them with the new mount point.
458  *
459  * Both old_nch and new_nch are ref'd on call but not locked.
460  * new_nch must be temporarily locked so it can be associated with the
461  * vnode representing the root of the mount point.
462  */
463 struct checkdirs_info {
464 	struct nchandle old_nch;
465 	struct nchandle new_nch;
466 	struct vnode *old_vp;
467 	struct vnode *new_vp;
468 };
469 
470 static int checkdirs_callback(struct proc *p, void *data);
471 
472 static void
473 checkdirs(struct nchandle *old_nch, struct nchandle *new_nch)
474 {
475 	struct checkdirs_info info;
476 	struct vnode *olddp;
477 	struct vnode *newdp;
478 	struct mount *mp;
479 
480 	/*
481 	 * If the old mount point's vnode has a usecount of 1, it is not
482 	 * being held as a descriptor anywhere.
483 	 */
484 	olddp = old_nch->ncp->nc_vp;
485 	if (olddp == NULL || VREFCNT(olddp) == 1)
486 		return;
487 
488 	/*
489 	 * Force the root vnode of the new mount point to be resolved
490 	 * so we can update any matching processes.
491 	 */
492 	mp = new_nch->mount;
493 	if (VFS_ROOT(mp, &newdp))
494 		panic("mount: lost mount");
495 	vn_unlock(newdp);
496 	cache_lock(new_nch);
497 	vn_lock(newdp, LK_EXCLUSIVE | LK_RETRY);
498 	cache_setunresolved(new_nch);
499 	cache_setvp(new_nch, newdp);
500 	cache_unlock(new_nch);
501 
502 	/*
503 	 * Special handling of the root node
504 	 */
505 	if (rootvnode == olddp) {
506 		vref(newdp);
507 		vfs_cache_setroot(newdp, cache_hold(new_nch));
508 	}
509 
510 	/*
511 	 * Pass newdp separately so the callback does not have to access
512 	 * it via new_nch->ncp->nc_vp.
513 	 */
514 	info.old_nch = *old_nch;
515 	info.new_nch = *new_nch;
516 	info.new_vp = newdp;
517 	allproc_scan(checkdirs_callback, &info, 0);
518 	vput(newdp);
519 }
520 
521 /*
522  * NOTE: callback is not MP safe because the scanned process's filedesc
523  * structure can be ripped out from under us, amoung other things.
524  */
525 static int
526 checkdirs_callback(struct proc *p, void *data)
527 {
528 	struct checkdirs_info *info = data;
529 	struct filedesc *fdp;
530 	struct nchandle ncdrop1;
531 	struct nchandle ncdrop2;
532 	struct vnode *vprele1;
533 	struct vnode *vprele2;
534 
535 	if ((fdp = p->p_fd) != NULL) {
536 		cache_zero(&ncdrop1);
537 		cache_zero(&ncdrop2);
538 		vprele1 = NULL;
539 		vprele2 = NULL;
540 
541 		/*
542 		 * MPUNSAFE - XXX fdp can be pulled out from under a
543 		 * foreign process.
544 		 *
545 		 * A shared filedesc is ok, we don't have to copy it
546 		 * because we are making this change globally.
547 		 */
548 		spin_lock(&fdp->fd_spin);
549 		if (fdp->fd_ncdir.mount == info->old_nch.mount &&
550 		    fdp->fd_ncdir.ncp == info->old_nch.ncp) {
551 			vprele1 = fdp->fd_cdir;
552 			vref(info->new_vp);
553 			fdp->fd_cdir = info->new_vp;
554 			ncdrop1 = fdp->fd_ncdir;
555 			cache_copy(&info->new_nch, &fdp->fd_ncdir);
556 		}
557 		if (fdp->fd_nrdir.mount == info->old_nch.mount &&
558 		    fdp->fd_nrdir.ncp == info->old_nch.ncp) {
559 			vprele2 = fdp->fd_rdir;
560 			vref(info->new_vp);
561 			fdp->fd_rdir = info->new_vp;
562 			ncdrop2 = fdp->fd_nrdir;
563 			cache_copy(&info->new_nch, &fdp->fd_nrdir);
564 		}
565 		spin_unlock(&fdp->fd_spin);
566 		if (ncdrop1.ncp)
567 			cache_drop(&ncdrop1);
568 		if (ncdrop2.ncp)
569 			cache_drop(&ncdrop2);
570 		if (vprele1)
571 			vrele(vprele1);
572 		if (vprele2)
573 			vrele(vprele2);
574 	}
575 	return(0);
576 }
577 
578 /*
579  * Unmount a file system.
580  *
581  * Note: unmount takes a path to the vnode mounted on as argument,
582  * not special file (as before).
583  *
584  * umount_args(char *path, int flags)
585  *
586  * MPALMOSTSAFE
587  */
588 int
589 sys_unmount(struct unmount_args *uap)
590 {
591 	struct thread *td = curthread;
592 	struct proc *p __debugvar = td->td_proc;
593 	struct mount *mp = NULL;
594 	struct nlookupdata nd;
595 	int error;
596 
597 	KKASSERT(p);
598 	if (td->td_ucred->cr_prison != NULL) {
599 		error = EPERM;
600 		goto done;
601 	}
602 	if (usermount == 0 && (error = priv_check(td, PRIV_ROOT)))
603 		goto done;
604 
605 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
606 	if (error == 0)
607 		error = nlookup(&nd);
608 	if (error)
609 		goto out;
610 
611 	mp = nd.nl_nch.mount;
612 
613 	/*
614 	 * Only root, or the user that did the original mount is
615 	 * permitted to unmount this filesystem.
616 	 */
617 	if ((mp->mnt_stat.f_owner != td->td_ucred->cr_uid) &&
618 	    (error = priv_check(td, PRIV_ROOT)))
619 		goto out;
620 
621 	/*
622 	 * Don't allow unmounting the root file system.
623 	 */
624 	if (mp->mnt_flag & MNT_ROOTFS) {
625 		error = EINVAL;
626 		goto out;
627 	}
628 
629 	/*
630 	 * Must be the root of the filesystem
631 	 */
632 	if (nd.nl_nch.ncp != mp->mnt_ncmountpt.ncp) {
633 		error = EINVAL;
634 		goto out;
635 	}
636 
637 	/*
638 	 * If no error try to issue the unmount.  We lose our cache
639 	 * ref when we call nlookup_done so we must hold the mount point
640 	 * to prevent use-after-free races.
641 	 */
642 out:
643 	if (error == 0) {
644 		mount_hold(mp);
645 		nlookup_done(&nd);
646 		error = dounmount(mp, uap->flags);
647 		mount_drop(mp);
648 	} else {
649 		nlookup_done(&nd);
650 	}
651 done:
652 	return (error);
653 }
654 
655 /*
656  * Do the actual file system unmount (interlocked against the mountlist
657  * token and mp->mnt_token).
658  */
659 static int
660 dounmount_interlock(struct mount *mp)
661 {
662 	if (mp->mnt_kern_flag & MNTK_UNMOUNT)
663 		return (EBUSY);
664 	mp->mnt_kern_flag |= MNTK_UNMOUNT;
665 	return(0);
666 }
667 
668 static int
669 unmount_allproc_cb(struct proc *p, void *arg)
670 {
671 	struct mount *mp;
672 
673 	if (p->p_textnch.ncp == NULL)
674 		return 0;
675 
676 	mp = (struct mount *)arg;
677 	if (p->p_textnch.mount == mp)
678 		cache_drop(&p->p_textnch);
679 
680 	return 0;
681 }
682 
683 /*
684  * The guts of the unmount code.  The mount owns one ref and one hold
685  * count.  If we successfully interlock the unmount, those refs are ours.
686  * (The ref is from mnt_ncmountpt).
687  */
688 int
689 dounmount(struct mount *mp, int flags)
690 {
691 	struct namecache *ncp;
692 	struct nchandle nch;
693 	struct vnode *vp;
694 	int error;
695 	int async_flag;
696 	int lflags;
697 	int freeok = 1;
698 	int retry;
699 
700 	lwkt_gettoken(&mp->mnt_token);
701 
702 	/*
703 	 * Exclusive access for unmounting purposes.
704 	 */
705 	if ((error = mountlist_interlock(dounmount_interlock, mp)) != 0)
706 		goto out;
707 
708 	/*
709 	 * We now 'own' the last mp->mnt_refs
710 	 *
711 	 * Allow filesystems to detect that a forced unmount is in progress.
712 	 */
713 	if (flags & MNT_FORCE)
714 		mp->mnt_kern_flag |= MNTK_UNMOUNTF;
715 	lflags = LK_EXCLUSIVE | ((flags & MNT_FORCE) ? 0 : LK_TIMELOCK);
716 	error = lockmgr(&mp->mnt_lock, lflags);
717 	if (error) {
718 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
719 		if (mp->mnt_kern_flag & MNTK_MWAIT) {
720 			mp->mnt_kern_flag &= ~MNTK_MWAIT;
721 			wakeup(mp);
722 		}
723 		goto out;
724 	}
725 
726 	if (mp->mnt_flag & MNT_EXPUBLIC)
727 		vfs_setpublicfs(NULL, NULL, NULL);
728 
729 	vfs_msync(mp, MNT_WAIT);
730 	async_flag = mp->mnt_flag & MNT_ASYNC;
731 	mp->mnt_flag &=~ MNT_ASYNC;
732 
733 	/*
734 	 * If this filesystem isn't aliasing other filesystems,
735 	 * try to invalidate any remaining namecache entries and
736 	 * check the count afterwords.
737 	 *
738 	 * We own the last mnt_refs by owning mnt_ncmountpt.
739 	 */
740 	if ((mp->mnt_kern_flag & MNTK_NCALIASED) == 0) {
741 		cache_lock(&mp->mnt_ncmountpt);
742 		cache_inval(&mp->mnt_ncmountpt, CINV_DESTROY|CINV_CHILDREN);
743 		cache_unlock(&mp->mnt_ncmountpt);
744 
745 		cache_clearmntcache();
746 		if ((ncp = mp->mnt_ncmountpt.ncp) != NULL &&
747 		    (ncp->nc_refs != 1 || TAILQ_FIRST(&ncp->nc_list))) {
748 			allproc_scan(&unmount_allproc_cb, mp, 0);
749 		}
750 
751 		cache_clearmntcache();
752 		if ((ncp = mp->mnt_ncmountpt.ncp) != NULL &&
753 		    (ncp->nc_refs != 1 || TAILQ_FIRST(&ncp->nc_list))) {
754 
755 			if ((flags & MNT_FORCE) == 0) {
756 				error = EBUSY;
757 				mount_warning(mp, "Cannot unmount: "
758 						  "%d namecache "
759 						  "references still "
760 						  "present",
761 						  ncp->nc_refs - 1);
762 			} else {
763 				mount_warning(mp, "Forced unmount: "
764 						  "%d namecache "
765 						  "references still "
766 						  "present",
767 						  ncp->nc_refs - 1);
768 				freeok = 0;
769 			}
770 		}
771 	}
772 
773 	/*
774 	 * Decomission our special mnt_syncer vnode.  This also stops
775 	 * the vnlru code.  If we are unable to unmount we recommission
776 	 * the vnode.
777 	 *
778 	 * Then sync the filesystem.
779 	 */
780 	if ((vp = mp->mnt_syncer) != NULL) {
781 		mp->mnt_syncer = NULL;
782 		atomic_set_int(&vp->v_refcnt, VREF_FINALIZE);
783 		vrele(vp);
784 	}
785 	if ((mp->mnt_flag & MNT_RDONLY) == 0)
786 		VFS_SYNC(mp, MNT_WAIT);
787 
788 	/*
789 	 * nchandle records ref the mount structure.  Expect a count of 1
790 	 * (our mount->mnt_ncmountpt).
791 	 *
792 	 * Scans can get temporary refs on a mountpoint (thought really
793 	 * heavy duty stuff like cache_findmount() do not).
794 	 */
795 	if (mp->mnt_refs != 1)
796 		cache_clearmntcache();
797 	for (retry = 0; retry < 10 && mp->mnt_refs != 1; ++retry) {
798 		cache_unmounting(mp);
799 		tsleep(&mp->mnt_refs, 0, "mntbsy", hz / 10 + 1);
800 		cache_clearmntcache();
801 	}
802 	if (mp->mnt_refs != 1) {
803 		if ((flags & MNT_FORCE) == 0) {
804 			mount_warning(mp, "Cannot unmount: "
805 					  "%d mount refs still present",
806 					  mp->mnt_refs - 1);
807 			error = EBUSY;
808 		} else {
809 			mount_warning(mp, "Forced unmount: "
810 					  "%d mount refs still present",
811 					  mp->mnt_refs - 1);
812 			freeok = 0;
813 		}
814 	}
815 
816 	/*
817 	 * So far so good, sync the filesystem once more and
818 	 * call the VFS unmount code if the sync succeeds.
819 	 */
820 	if (error == 0) {
821 		if (mp->mnt_flag & MNT_RDONLY) {
822 			error = VFS_UNMOUNT(mp, flags);
823 		} else {
824 			error = VFS_SYNC(mp, MNT_WAIT);
825 			if ((error == 0) ||
826 			    (error == EOPNOTSUPP) || /* No sync */
827 			    (flags & MNT_FORCE)) {
828 				error = VFS_UNMOUNT(mp, flags);
829 			}
830 		}
831 	}
832 
833 	/*
834 	 * If an error occurred we can still recover, restoring the
835 	 * syncer vnode and misc flags.
836 	 */
837 	if (error) {
838 		if (mp->mnt_syncer == NULL)
839 			vfs_allocate_syncvnode(mp);
840 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
841 		mp->mnt_flag |= async_flag;
842 		lockmgr(&mp->mnt_lock, LK_RELEASE);
843 		if (mp->mnt_kern_flag & MNTK_MWAIT) {
844 			mp->mnt_kern_flag &= ~MNTK_MWAIT;
845 			wakeup(mp);
846 		}
847 		goto out;
848 	}
849 	/*
850 	 * Clean up any journals still associated with the mount after
851 	 * filesystem activity has ceased.
852 	 */
853 	journal_remove_all_journals(mp,
854 	    ((flags & MNT_FORCE) ? MC_JOURNAL_STOP_IMM : 0));
855 
856 	mountlist_remove(mp);
857 
858 	/*
859 	 * Remove any installed vnode ops here so the individual VFSs don't
860 	 * have to.
861 	 *
862 	 * mnt_refs should go to zero when we scrap mnt_ncmountpt.
863 	 */
864 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
865 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
866 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
867 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
868 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
869 
870 	if (mp->mnt_ncmountpt.ncp != NULL) {
871 		nch = mp->mnt_ncmountpt;
872 		cache_zero(&mp->mnt_ncmountpt);
873 		cache_clrmountpt(&nch);
874 		cache_drop(&nch);
875 	}
876 	if (mp->mnt_ncmounton.ncp != NULL) {
877 		cache_unmounting(mp);
878 		nch = mp->mnt_ncmounton;
879 		cache_zero(&mp->mnt_ncmounton);
880 		cache_clrmountpt(&nch);
881 		cache_drop(&nch);
882 	}
883 
884 	mp->mnt_vfc->vfc_refcount--;
885 	if (!TAILQ_EMPTY(&mp->mnt_nvnodelist))
886 		panic("unmount: dangling vnode");
887 
888 	/*
889 	 * Release the lock
890 	 */
891 	lockmgr(&mp->mnt_lock, LK_RELEASE);
892 	if (mp->mnt_kern_flag & MNTK_MWAIT) {
893 		mp->mnt_kern_flag &= ~MNTK_MWAIT;
894 		wakeup(mp);
895 	}
896 
897 	/*
898 	 * If we reach here and freeok != 0 we must free the mount.
899 	 * mnt_refs should already have dropped to 0, so if it is not
900 	 * zero we must cycle the caches and wait.
901 	 *
902 	 * When we are satisfied that the mount has disconnected we can
903 	 * drop the hold on the mp that represented the mount (though the
904 	 * caller might actually have another, so the caller's drop may
905 	 * do the actual free).
906 	 */
907 	if (freeok) {
908 		if (mp->mnt_refs > 0)
909 			cache_clearmntcache();
910 		while (mp->mnt_refs > 0) {
911 			cache_unmounting(mp);
912 			wakeup(mp);
913 			tsleep(&mp->mnt_refs, 0, "umntrwait", hz / 10 + 1);
914 			cache_clearmntcache();
915 		}
916 		lwkt_reltoken(&mp->mnt_token);
917 		mount_drop(mp);
918 		mp = NULL;
919 	}
920 	error = 0;
921 	KNOTE(&fs_klist, VQ_UNMOUNT);
922 out:
923 	if (mp)
924 		lwkt_reltoken(&mp->mnt_token);
925 	return (error);
926 }
927 
928 static
929 void
930 mount_warning(struct mount *mp, const char *ctl, ...)
931 {
932 	char *ptr;
933 	char *buf;
934 	__va_list va;
935 
936 	__va_start(va, ctl);
937 	if (cache_fullpath(NULL, &mp->mnt_ncmounton, NULL,
938 			   &ptr, &buf, 0) == 0) {
939 		kprintf("unmount(%s): ", ptr);
940 		kvprintf(ctl, va);
941 		kprintf("\n");
942 		kfree(buf, M_TEMP);
943 	} else {
944 		kprintf("unmount(%p", mp);
945 		if (mp->mnt_ncmounton.ncp && mp->mnt_ncmounton.ncp->nc_name)
946 			kprintf(",%s", mp->mnt_ncmounton.ncp->nc_name);
947 		kprintf("): ");
948 		kvprintf(ctl, va);
949 		kprintf("\n");
950 	}
951 	__va_end(va);
952 }
953 
954 /*
955  * Shim cache_fullpath() to handle the case where a process is chrooted into
956  * a subdirectory of a mount.  In this case if the root mount matches the
957  * process root directory's mount we have to specify the process's root
958  * directory instead of the mount point, because the mount point might
959  * be above the root directory.
960  */
961 static
962 int
963 mount_path(struct proc *p, struct mount *mp, char **rb, char **fb)
964 {
965 	struct nchandle *nch;
966 
967 	if (p && p->p_fd->fd_nrdir.mount == mp)
968 		nch = &p->p_fd->fd_nrdir;
969 	else
970 		nch = &mp->mnt_ncmountpt;
971 	return(cache_fullpath(p, nch, NULL, rb, fb, 0));
972 }
973 
974 /*
975  * Sync each mounted filesystem.
976  */
977 
978 #ifdef DEBUG
979 static int syncprt = 0;
980 SYSCTL_INT(_debug, OID_AUTO, syncprt, CTLFLAG_RW, &syncprt, 0, "");
981 #endif /* DEBUG */
982 
983 static int sync_callback(struct mount *mp, void *data);
984 
985 int
986 sys_sync(struct sync_args *uap)
987 {
988 	mountlist_scan(sync_callback, NULL, MNTSCAN_FORWARD);
989 	return (0);
990 }
991 
992 static
993 int
994 sync_callback(struct mount *mp, void *data __unused)
995 {
996 	int asyncflag;
997 
998 	if ((mp->mnt_flag & MNT_RDONLY) == 0) {
999 		asyncflag = mp->mnt_flag & MNT_ASYNC;
1000 		mp->mnt_flag &= ~MNT_ASYNC;
1001 		vfs_msync(mp, MNT_NOWAIT);
1002 		VFS_SYNC(mp, MNT_NOWAIT);
1003 		mp->mnt_flag |= asyncflag;
1004 	}
1005 	return(0);
1006 }
1007 
1008 /* XXX PRISON: could be per prison flag */
1009 static int prison_quotas;
1010 #if 0
1011 SYSCTL_INT(_kern_prison, OID_AUTO, quotas, CTLFLAG_RW, &prison_quotas, 0, "");
1012 #endif
1013 
1014 /*
1015  *  quotactl_args(char *path, int fcmd, int uid, caddr_t arg)
1016  *
1017  * Change filesystem quotas.
1018  *
1019  * MPALMOSTSAFE
1020  */
1021 int
1022 sys_quotactl(struct quotactl_args *uap)
1023 {
1024 	struct nlookupdata nd;
1025 	struct thread *td;
1026 	struct mount *mp;
1027 	int error;
1028 
1029 	td = curthread;
1030 	if (td->td_ucred->cr_prison && !prison_quotas) {
1031 		error = EPERM;
1032 		goto done;
1033 	}
1034 
1035 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1036 	if (error == 0)
1037 		error = nlookup(&nd);
1038 	if (error == 0) {
1039 		mp = nd.nl_nch.mount;
1040 		error = VFS_QUOTACTL(mp, uap->cmd, uap->uid,
1041 				    uap->arg, nd.nl_cred);
1042 	}
1043 	nlookup_done(&nd);
1044 done:
1045 	return (error);
1046 }
1047 
1048 /*
1049  * mountctl(char *path, int op, int fd, const void *ctl, int ctllen,
1050  *		void *buf, int buflen)
1051  *
1052  * This function operates on a mount point and executes the specified
1053  * operation using the specified control data, and possibly returns data.
1054  *
1055  * The actual number of bytes stored in the result buffer is returned, 0
1056  * if none, otherwise an error is returned.
1057  *
1058  * MPALMOSTSAFE
1059  */
1060 int
1061 sys_mountctl(struct mountctl_args *uap)
1062 {
1063 	struct thread *td = curthread;
1064 	struct proc *p = td->td_proc;
1065 	struct file *fp;
1066 	void *ctl = NULL;
1067 	void *buf = NULL;
1068 	char *path = NULL;
1069 	int error;
1070 
1071 	/*
1072 	 * Sanity and permissions checks.  We must be root.
1073 	 */
1074 	KKASSERT(p);
1075 	if (td->td_ucred->cr_prison != NULL)
1076 		return (EPERM);
1077 	if ((uap->op != MOUNTCTL_MOUNTFLAGS) &&
1078 	    (error = priv_check(td, PRIV_ROOT)) != 0)
1079 		return (error);
1080 
1081 	/*
1082 	 * Argument length checks
1083 	 */
1084 	if (uap->ctllen < 0 || uap->ctllen > 1024)
1085 		return (EINVAL);
1086 	if (uap->buflen < 0 || uap->buflen > 16 * 1024)
1087 		return (EINVAL);
1088 	if (uap->path == NULL)
1089 		return (EINVAL);
1090 
1091 	/*
1092 	 * Allocate the necessary buffers and copyin data
1093 	 */
1094 	path = objcache_get(namei_oc, M_WAITOK);
1095 	error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
1096 	if (error)
1097 		goto done;
1098 
1099 	if (uap->ctllen) {
1100 		ctl = kmalloc(uap->ctllen + 1, M_TEMP, M_WAITOK|M_ZERO);
1101 		error = copyin(uap->ctl, ctl, uap->ctllen);
1102 		if (error)
1103 			goto done;
1104 	}
1105 	if (uap->buflen)
1106 		buf = kmalloc(uap->buflen + 1, M_TEMP, M_WAITOK|M_ZERO);
1107 
1108 	/*
1109 	 * Validate the descriptor
1110 	 */
1111 	if (uap->fd >= 0) {
1112 		fp = holdfp(p->p_fd, uap->fd, -1);
1113 		if (fp == NULL) {
1114 			error = EBADF;
1115 			goto done;
1116 		}
1117 	} else {
1118 		fp = NULL;
1119 	}
1120 
1121 	/*
1122 	 * Execute the internal kernel function and clean up.
1123 	 */
1124 	error = kern_mountctl(path, uap->op, fp, ctl, uap->ctllen, buf, uap->buflen, &uap->sysmsg_result);
1125 	if (fp)
1126 		fdrop(fp);
1127 	if (error == 0 && uap->sysmsg_result > 0)
1128 		error = copyout(buf, uap->buf, uap->sysmsg_result);
1129 done:
1130 	if (path)
1131 		objcache_put(namei_oc, path);
1132 	if (ctl)
1133 		kfree(ctl, M_TEMP);
1134 	if (buf)
1135 		kfree(buf, M_TEMP);
1136 	return (error);
1137 }
1138 
1139 /*
1140  * Execute a mount control operation by resolving the path to a mount point
1141  * and calling vop_mountctl().
1142  *
1143  * Use the mount point from the nch instead of the vnode so nullfs mounts
1144  * can properly spike the VOP.
1145  */
1146 int
1147 kern_mountctl(const char *path, int op, struct file *fp,
1148 		const void *ctl, int ctllen,
1149 		void *buf, int buflen, int *res)
1150 {
1151 	struct vnode *vp;
1152 	struct nlookupdata nd;
1153 	struct nchandle nch;
1154 	struct mount *mp;
1155 	int error;
1156 
1157 	*res = 0;
1158 	vp = NULL;
1159 	error = nlookup_init(&nd, path, UIO_SYSSPACE, NLC_FOLLOW);
1160 	if (error)
1161 		return (error);
1162 	error = nlookup(&nd);
1163 	if (error) {
1164 		nlookup_done(&nd);
1165 		return (error);
1166 	}
1167 	error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
1168 	if (error) {
1169 		nlookup_done(&nd);
1170 		return (error);
1171 	}
1172 
1173 	/*
1174 	 * Yes, all this is needed to use the nch.mount below, because
1175 	 * we must maintain a ref on the mount to avoid ripouts (e.g.
1176 	 * due to heavy mount/unmount use by synth or poudriere).
1177 	 */
1178 	nch = nd.nl_nch;
1179 	cache_zero(&nd.nl_nch);
1180 	cache_unlock(&nch);
1181 	nlookup_done(&nd);
1182 	vn_unlock(vp);
1183 
1184 	mp = nch.mount;
1185 
1186 	/*
1187 	 * Must be the root of the filesystem
1188 	 */
1189 	if ((vp->v_flag & (VROOT|VPFSROOT)) == 0) {
1190 		cache_drop(&nch);
1191 		vrele(vp);
1192 		return (EINVAL);
1193 	}
1194 	if (mp == NULL || mp->mnt_kern_flag & MNTK_UNMOUNT) {
1195 		kprintf("kern_mountctl: Warning, \"%s\" racing unmount\n",
1196 			path);
1197 		cache_drop(&nch);
1198 		vrele(vp);
1199 		return (EINVAL);
1200 	}
1201 	error = vop_mountctl(mp->mnt_vn_use_ops, vp, op, fp, ctl, ctllen,
1202 			     buf, buflen, res);
1203 	vrele(vp);
1204 	cache_drop(&nch);
1205 
1206 	return (error);
1207 }
1208 
1209 int
1210 kern_statfs(struct nlookupdata *nd, struct statfs *buf)
1211 {
1212 	struct thread *td = curthread;
1213 	struct proc *p = td->td_proc;
1214 	struct mount *mp;
1215 	struct statfs *sp;
1216 	char *fullpath, *freepath;
1217 	int error;
1218 
1219 	if ((error = nlookup(nd)) != 0)
1220 		return (error);
1221 	mp = nd->nl_nch.mount;
1222 	sp = &mp->mnt_stat;
1223 	if ((error = VFS_STATFS(mp, sp, nd->nl_cred)) != 0)
1224 		return (error);
1225 
1226 	error = mount_path(p, mp, &fullpath, &freepath);
1227 	if (error)
1228 		return(error);
1229 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1230 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1231 	kfree(freepath, M_TEMP);
1232 
1233 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1234 	bcopy(sp, buf, sizeof(*buf));
1235 	/* Only root should have access to the fsid's. */
1236 	if (priv_check(td, PRIV_ROOT))
1237 		buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
1238 	return (0);
1239 }
1240 
1241 /*
1242  * statfs_args(char *path, struct statfs *buf)
1243  *
1244  * Get filesystem statistics.
1245  */
1246 int
1247 sys_statfs(struct statfs_args *uap)
1248 {
1249 	struct nlookupdata nd;
1250 	struct statfs buf;
1251 	int error;
1252 
1253 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1254 	if (error == 0)
1255 		error = kern_statfs(&nd, &buf);
1256 	nlookup_done(&nd);
1257 	if (error == 0)
1258 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1259 	return (error);
1260 }
1261 
1262 int
1263 kern_fstatfs(int fd, struct statfs *buf)
1264 {
1265 	struct thread *td = curthread;
1266 	struct proc *p = td->td_proc;
1267 	struct file *fp;
1268 	struct mount *mp;
1269 	struct statfs *sp;
1270 	char *fullpath, *freepath;
1271 	int error;
1272 
1273 	KKASSERT(p);
1274 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
1275 		return (error);
1276 
1277 	/*
1278 	 * Try to use mount info from any overlays rather than the
1279 	 * mount info for the underlying vnode, otherwise we will
1280 	 * fail when operating on null-mounted paths inside a chroot.
1281 	 */
1282 	if ((mp = fp->f_nchandle.mount) == NULL)
1283 		mp = ((struct vnode *)fp->f_data)->v_mount;
1284 	if (mp == NULL) {
1285 		error = EBADF;
1286 		goto done;
1287 	}
1288 	if (fp->f_cred == NULL) {
1289 		error = EINVAL;
1290 		goto done;
1291 	}
1292 	sp = &mp->mnt_stat;
1293 	if ((error = VFS_STATFS(mp, sp, fp->f_cred)) != 0)
1294 		goto done;
1295 
1296 	if ((error = mount_path(p, mp, &fullpath, &freepath)) != 0)
1297 		goto done;
1298 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1299 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1300 	kfree(freepath, M_TEMP);
1301 
1302 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1303 	bcopy(sp, buf, sizeof(*buf));
1304 
1305 	/* Only root should have access to the fsid's. */
1306 	if (priv_check(td, PRIV_ROOT))
1307 		buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
1308 	error = 0;
1309 done:
1310 	fdrop(fp);
1311 	return (error);
1312 }
1313 
1314 /*
1315  * fstatfs_args(int fd, struct statfs *buf)
1316  *
1317  * Get filesystem statistics.
1318  */
1319 int
1320 sys_fstatfs(struct fstatfs_args *uap)
1321 {
1322 	struct statfs buf;
1323 	int error;
1324 
1325 	error = kern_fstatfs(uap->fd, &buf);
1326 
1327 	if (error == 0)
1328 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1329 	return (error);
1330 }
1331 
1332 int
1333 kern_statvfs(struct nlookupdata *nd, struct statvfs *buf)
1334 {
1335 	struct mount *mp;
1336 	struct statvfs *sp;
1337 	int error;
1338 
1339 	if ((error = nlookup(nd)) != 0)
1340 		return (error);
1341 	mp = nd->nl_nch.mount;
1342 	sp = &mp->mnt_vstat;
1343 	if ((error = VFS_STATVFS(mp, sp, nd->nl_cred)) != 0)
1344 		return (error);
1345 
1346 	sp->f_flag = 0;
1347 	if (mp->mnt_flag & MNT_RDONLY)
1348 		sp->f_flag |= ST_RDONLY;
1349 	if (mp->mnt_flag & MNT_NOSUID)
1350 		sp->f_flag |= ST_NOSUID;
1351 	bcopy(sp, buf, sizeof(*buf));
1352 	return (0);
1353 }
1354 
1355 /*
1356  * statfs_args(char *path, struct statfs *buf)
1357  *
1358  * Get filesystem statistics.
1359  */
1360 int
1361 sys_statvfs(struct statvfs_args *uap)
1362 {
1363 	struct nlookupdata nd;
1364 	struct statvfs buf;
1365 	int error;
1366 
1367 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1368 	if (error == 0)
1369 		error = kern_statvfs(&nd, &buf);
1370 	nlookup_done(&nd);
1371 	if (error == 0)
1372 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1373 	return (error);
1374 }
1375 
1376 int
1377 kern_fstatvfs(int fd, struct statvfs *buf)
1378 {
1379 	struct thread *td = curthread;
1380 	struct proc *p = td->td_proc;
1381 	struct file *fp;
1382 	struct mount *mp;
1383 	struct statvfs *sp;
1384 	int error;
1385 
1386 	KKASSERT(p);
1387 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
1388 		return (error);
1389 	if ((mp = fp->f_nchandle.mount) == NULL)
1390 		mp = ((struct vnode *)fp->f_data)->v_mount;
1391 	if (mp == NULL) {
1392 		error = EBADF;
1393 		goto done;
1394 	}
1395 	if (fp->f_cred == NULL) {
1396 		error = EINVAL;
1397 		goto done;
1398 	}
1399 	sp = &mp->mnt_vstat;
1400 	if ((error = VFS_STATVFS(mp, sp, fp->f_cred)) != 0)
1401 		goto done;
1402 
1403 	sp->f_flag = 0;
1404 	if (mp->mnt_flag & MNT_RDONLY)
1405 		sp->f_flag |= ST_RDONLY;
1406 	if (mp->mnt_flag & MNT_NOSUID)
1407 		sp->f_flag |= ST_NOSUID;
1408 
1409 	bcopy(sp, buf, sizeof(*buf));
1410 	error = 0;
1411 done:
1412 	fdrop(fp);
1413 	return (error);
1414 }
1415 
1416 /*
1417  * fstatfs_args(int fd, struct statfs *buf)
1418  *
1419  * Get filesystem statistics.
1420  */
1421 int
1422 sys_fstatvfs(struct fstatvfs_args *uap)
1423 {
1424 	struct statvfs buf;
1425 	int error;
1426 
1427 	error = kern_fstatvfs(uap->fd, &buf);
1428 
1429 	if (error == 0)
1430 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1431 	return (error);
1432 }
1433 
1434 /*
1435  * getfsstat_args(struct statfs *buf, long bufsize, int flags)
1436  *
1437  * Get statistics on all filesystems.
1438  */
1439 
1440 struct getfsstat_info {
1441 	struct statfs *sfsp;
1442 	long count;
1443 	long maxcount;
1444 	int error;
1445 	int flags;
1446 	struct thread *td;
1447 };
1448 
1449 static int getfsstat_callback(struct mount *, void *);
1450 
1451 int
1452 sys_getfsstat(struct getfsstat_args *uap)
1453 {
1454 	struct thread *td = curthread;
1455 	struct getfsstat_info info;
1456 
1457 	bzero(&info, sizeof(info));
1458 
1459 	info.maxcount = uap->bufsize / sizeof(struct statfs);
1460 	info.sfsp = uap->buf;
1461 	info.count = 0;
1462 	info.flags = uap->flags;
1463 	info.td = td;
1464 
1465 	mountlist_scan(getfsstat_callback, &info, MNTSCAN_FORWARD);
1466 	if (info.sfsp && info.count > info.maxcount)
1467 		uap->sysmsg_result = info.maxcount;
1468 	else
1469 		uap->sysmsg_result = info.count;
1470 	return (info.error);
1471 }
1472 
1473 static int
1474 getfsstat_callback(struct mount *mp, void *data)
1475 {
1476 	struct getfsstat_info *info = data;
1477 	struct statfs *sp;
1478 	char *freepath;
1479 	char *fullpath;
1480 	int error;
1481 
1482 	if (info->sfsp && info->count < info->maxcount) {
1483 		if (info->td->td_proc &&
1484 		    !chroot_visible_mnt(mp, info->td->td_proc)) {
1485 			return(0);
1486 		}
1487 		sp = &mp->mnt_stat;
1488 
1489 		/*
1490 		 * If MNT_NOWAIT or MNT_LAZY is specified, do not
1491 		 * refresh the fsstat cache. MNT_NOWAIT or MNT_LAZY
1492 		 * overrides MNT_WAIT.
1493 		 */
1494 		if (((info->flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
1495 		    (info->flags & MNT_WAIT)) &&
1496 		    (error = VFS_STATFS(mp, sp, info->td->td_ucred))) {
1497 			return(0);
1498 		}
1499 		sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1500 
1501 		error = mount_path(info->td->td_proc, mp, &fullpath, &freepath);
1502 		if (error) {
1503 			info->error = error;
1504 			return(-1);
1505 		}
1506 		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1507 		strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1508 		kfree(freepath, M_TEMP);
1509 
1510 		error = copyout(sp, info->sfsp, sizeof(*sp));
1511 		if (error) {
1512 			info->error = error;
1513 			return (-1);
1514 		}
1515 		++info->sfsp;
1516 	}
1517 	info->count++;
1518 	return(0);
1519 }
1520 
1521 /*
1522  * getvfsstat_args(struct statfs *buf, struct statvfs *vbuf,
1523 		   long bufsize, int flags)
1524  *
1525  * Get statistics on all filesystems.
1526  */
1527 
1528 struct getvfsstat_info {
1529 	struct statfs *sfsp;
1530 	struct statvfs *vsfsp;
1531 	long count;
1532 	long maxcount;
1533 	int error;
1534 	int flags;
1535 	struct thread *td;
1536 };
1537 
1538 static int getvfsstat_callback(struct mount *, void *);
1539 
1540 int
1541 sys_getvfsstat(struct getvfsstat_args *uap)
1542 {
1543 	struct thread *td = curthread;
1544 	struct getvfsstat_info info;
1545 
1546 	bzero(&info, sizeof(info));
1547 
1548 	info.maxcount = uap->vbufsize / sizeof(struct statvfs);
1549 	info.sfsp = uap->buf;
1550 	info.vsfsp = uap->vbuf;
1551 	info.count = 0;
1552 	info.flags = uap->flags;
1553 	info.td = td;
1554 
1555 	mountlist_scan(getvfsstat_callback, &info, MNTSCAN_FORWARD);
1556 	if (info.vsfsp && info.count > info.maxcount)
1557 		uap->sysmsg_result = info.maxcount;
1558 	else
1559 		uap->sysmsg_result = info.count;
1560 	return (info.error);
1561 }
1562 
1563 static int
1564 getvfsstat_callback(struct mount *mp, void *data)
1565 {
1566 	struct getvfsstat_info *info = data;
1567 	struct statfs *sp;
1568 	struct statvfs *vsp;
1569 	char *freepath;
1570 	char *fullpath;
1571 	int error;
1572 
1573 	if (info->vsfsp && info->count < info->maxcount) {
1574 		if (info->td->td_proc &&
1575 		    !chroot_visible_mnt(mp, info->td->td_proc)) {
1576 			return(0);
1577 		}
1578 		sp = &mp->mnt_stat;
1579 		vsp = &mp->mnt_vstat;
1580 
1581 		/*
1582 		 * If MNT_NOWAIT or MNT_LAZY is specified, do not
1583 		 * refresh the fsstat cache. MNT_NOWAIT or MNT_LAZY
1584 		 * overrides MNT_WAIT.
1585 		 */
1586 		if (((info->flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
1587 		    (info->flags & MNT_WAIT)) &&
1588 		    (error = VFS_STATFS(mp, sp, info->td->td_ucred))) {
1589 			return(0);
1590 		}
1591 		sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1592 
1593 		if (((info->flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
1594 		    (info->flags & MNT_WAIT)) &&
1595 		    (error = VFS_STATVFS(mp, vsp, info->td->td_ucred))) {
1596 			return(0);
1597 		}
1598 		vsp->f_flag = 0;
1599 		if (mp->mnt_flag & MNT_RDONLY)
1600 			vsp->f_flag |= ST_RDONLY;
1601 		if (mp->mnt_flag & MNT_NOSUID)
1602 			vsp->f_flag |= ST_NOSUID;
1603 
1604 		error = mount_path(info->td->td_proc, mp, &fullpath, &freepath);
1605 		if (error) {
1606 			info->error = error;
1607 			return(-1);
1608 		}
1609 		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1610 		strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1611 		kfree(freepath, M_TEMP);
1612 
1613 		error = copyout(sp, info->sfsp, sizeof(*sp));
1614 		if (error == 0)
1615 			error = copyout(vsp, info->vsfsp, sizeof(*vsp));
1616 		if (error) {
1617 			info->error = error;
1618 			return (-1);
1619 		}
1620 		++info->sfsp;
1621 		++info->vsfsp;
1622 	}
1623 	info->count++;
1624 	return(0);
1625 }
1626 
1627 
1628 /*
1629  * fchdir_args(int fd)
1630  *
1631  * Change current working directory to a given file descriptor.
1632  */
1633 int
1634 sys_fchdir(struct fchdir_args *uap)
1635 {
1636 	struct thread *td = curthread;
1637 	struct proc *p = td->td_proc;
1638 	struct filedesc *fdp = p->p_fd;
1639 	struct vnode *vp, *ovp;
1640 	struct mount *mp;
1641 	struct file *fp;
1642 	struct nchandle nch, onch, tnch;
1643 	int error;
1644 
1645 	if ((error = holdvnode(fdp, uap->fd, &fp)) != 0)
1646 		return (error);
1647 	lwkt_gettoken(&p->p_token);
1648 	vp = (struct vnode *)fp->f_data;
1649 	vref(vp);
1650 	vn_lock(vp, LK_SHARED | LK_RETRY);
1651 	if (fp->f_nchandle.ncp == NULL)
1652 		error = ENOTDIR;
1653 	else
1654 		error = checkvp_chdir(vp, td);
1655 	if (error) {
1656 		vput(vp);
1657 		goto done;
1658 	}
1659 	cache_copy(&fp->f_nchandle, &nch);
1660 
1661 	/*
1662 	 * If the ncp has become a mount point, traverse through
1663 	 * the mount point.
1664 	 */
1665 
1666 	while (!error && (nch.ncp->nc_flag & NCF_ISMOUNTPT) &&
1667 	       (mp = cache_findmount(&nch)) != NULL
1668 	) {
1669 		error = nlookup_mp(mp, &tnch);
1670 		if (error == 0) {
1671 			cache_unlock(&tnch);	/* leave ref intact */
1672 			vput(vp);
1673 			vp = tnch.ncp->nc_vp;
1674 			error = vget(vp, LK_SHARED);
1675 			KKASSERT(error == 0);
1676 			cache_drop(&nch);
1677 			nch = tnch;
1678 		}
1679 		cache_dropmount(mp);
1680 	}
1681 	if (error == 0) {
1682 		spin_lock(&fdp->fd_spin);
1683 		ovp = fdp->fd_cdir;
1684 		onch = fdp->fd_ncdir;
1685 		fdp->fd_cdir = vp;
1686 		fdp->fd_ncdir = nch;
1687 		spin_unlock(&fdp->fd_spin);
1688 		vn_unlock(vp);		/* leave ref intact */
1689 		cache_drop(&onch);
1690 		vrele(ovp);
1691 	} else {
1692 		cache_drop(&nch);
1693 		vput(vp);
1694 	}
1695 	fdrop(fp);
1696 done:
1697 	lwkt_reltoken(&p->p_token);
1698 	return (error);
1699 }
1700 
1701 int
1702 kern_chdir(struct nlookupdata *nd)
1703 {
1704 	struct thread *td = curthread;
1705 	struct proc *p = td->td_proc;
1706 	struct filedesc *fdp = p->p_fd;
1707 	struct vnode *vp, *ovp;
1708 	struct nchandle onch;
1709 	int error;
1710 
1711 	nd->nl_flags |= NLC_SHAREDLOCK;
1712 	if ((error = nlookup(nd)) != 0)
1713 		return (error);
1714 	if ((vp = nd->nl_nch.ncp->nc_vp) == NULL)
1715 		return (ENOENT);
1716 	if ((error = vget(vp, LK_SHARED)) != 0)
1717 		return (error);
1718 
1719 	lwkt_gettoken(&p->p_token);
1720 	error = checkvp_chdir(vp, td);
1721 	vn_unlock(vp);
1722 	if (error == 0) {
1723 		spin_lock(&fdp->fd_spin);
1724 		ovp = fdp->fd_cdir;
1725 		onch = fdp->fd_ncdir;
1726 		fdp->fd_ncdir = nd->nl_nch;
1727 		fdp->fd_cdir = vp;
1728 		spin_unlock(&fdp->fd_spin);
1729 		cache_unlock(&nd->nl_nch);	/* leave reference intact */
1730 		cache_drop(&onch);
1731 		vrele(ovp);
1732 		cache_zero(&nd->nl_nch);
1733 	} else {
1734 		vrele(vp);
1735 	}
1736 	lwkt_reltoken(&p->p_token);
1737 	return (error);
1738 }
1739 
1740 /*
1741  * chdir_args(char *path)
1742  *
1743  * Change current working directory (``.'').
1744  */
1745 int
1746 sys_chdir(struct chdir_args *uap)
1747 {
1748 	struct nlookupdata nd;
1749 	int error;
1750 
1751 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1752 	if (error == 0)
1753 		error = kern_chdir(&nd);
1754 	nlookup_done(&nd);
1755 	return (error);
1756 }
1757 
1758 /*
1759  * Helper function for raised chroot(2) security function:  Refuse if
1760  * any filedescriptors are open directories.
1761  */
1762 static int
1763 chroot_refuse_vdir_fds(struct filedesc *fdp)
1764 {
1765 	struct vnode *vp;
1766 	struct file *fp;
1767 	int error;
1768 	int fd;
1769 
1770 	for (fd = 0; fd < fdp->fd_nfiles ; fd++) {
1771 		if ((error = holdvnode(fdp, fd, &fp)) != 0)
1772 			continue;
1773 		vp = (struct vnode *)fp->f_data;
1774 		if (vp->v_type != VDIR) {
1775 			fdrop(fp);
1776 			continue;
1777 		}
1778 		fdrop(fp);
1779 		return(EPERM);
1780 	}
1781 	return (0);
1782 }
1783 
1784 /*
1785  * This sysctl determines if we will allow a process to chroot(2) if it
1786  * has a directory open:
1787  *	0: disallowed for all processes.
1788  *	1: allowed for processes that were not already chroot(2)'ed.
1789  *	2: allowed for all processes.
1790  */
1791 
1792 static int chroot_allow_open_directories = 1;
1793 
1794 SYSCTL_INT(_kern, OID_AUTO, chroot_allow_open_directories, CTLFLAG_RW,
1795      &chroot_allow_open_directories, 0, "");
1796 
1797 /*
1798  * chroot to the specified namecache entry.  We obtain the vp from the
1799  * namecache data.  The passed ncp must be locked and referenced and will
1800  * remain locked and referenced on return.
1801  */
1802 int
1803 kern_chroot(struct nchandle *nch)
1804 {
1805 	struct thread *td = curthread;
1806 	struct proc *p = td->td_proc;
1807 	struct filedesc *fdp = p->p_fd;
1808 	struct vnode *vp;
1809 	int error;
1810 
1811 	/*
1812 	 * Only privileged user can chroot
1813 	 */
1814 	error = priv_check_cred(td->td_ucred, PRIV_VFS_CHROOT, 0);
1815 	if (error)
1816 		return (error);
1817 
1818 	/*
1819 	 * Disallow open directory descriptors (fchdir() breakouts).
1820 	 */
1821 	if (chroot_allow_open_directories == 0 ||
1822 	   (chroot_allow_open_directories == 1 && fdp->fd_rdir != rootvnode)) {
1823 		if ((error = chroot_refuse_vdir_fds(fdp)) != 0)
1824 			return (error);
1825 	}
1826 	if ((vp = nch->ncp->nc_vp) == NULL)
1827 		return (ENOENT);
1828 
1829 	if ((error = vget(vp, LK_SHARED)) != 0)
1830 		return (error);
1831 
1832 	/*
1833 	 * Check the validity of vp as a directory to change to and
1834 	 * associate it with rdir/jdir.
1835 	 */
1836 	error = checkvp_chdir(vp, td);
1837 	vn_unlock(vp);			/* leave reference intact */
1838 	if (error == 0) {
1839 		lwkt_gettoken(&p->p_token);
1840 		vrele(fdp->fd_rdir);
1841 		fdp->fd_rdir = vp;	/* reference inherited by fd_rdir */
1842 		cache_drop(&fdp->fd_nrdir);
1843 		cache_copy(nch, &fdp->fd_nrdir);
1844 		if (fdp->fd_jdir == NULL) {
1845 			fdp->fd_jdir = vp;
1846 			vref(fdp->fd_jdir);
1847 			cache_copy(nch, &fdp->fd_njdir);
1848 		}
1849 		if ((p->p_flags & P_DIDCHROOT) == 0) {
1850 			p->p_flags |= P_DIDCHROOT;
1851 			if (p->p_depth <= 65535 - 32)
1852 				p->p_depth += 32;
1853 		}
1854 		lwkt_reltoken(&p->p_token);
1855 	} else {
1856 		vrele(vp);
1857 	}
1858 	return (error);
1859 }
1860 
1861 /*
1862  * chroot_args(char *path)
1863  *
1864  * Change notion of root (``/'') directory.
1865  */
1866 int
1867 sys_chroot(struct chroot_args *uap)
1868 {
1869 	struct thread *td __debugvar = curthread;
1870 	struct nlookupdata nd;
1871 	int error;
1872 
1873 	KKASSERT(td->td_proc);
1874 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1875 	if (error == 0) {
1876 		nd.nl_flags |= NLC_EXEC;
1877 		error = nlookup(&nd);
1878 		if (error == 0)
1879 			error = kern_chroot(&nd.nl_nch);
1880 	}
1881 	nlookup_done(&nd);
1882 	return(error);
1883 }
1884 
1885 int
1886 sys_chroot_kernel(struct chroot_kernel_args *uap)
1887 {
1888 	struct thread *td = curthread;
1889 	struct nlookupdata nd;
1890 	struct nchandle *nch;
1891 	struct vnode *vp;
1892 	int error;
1893 
1894 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1895 	if (error)
1896 		goto error_nond;
1897 
1898 	error = nlookup(&nd);
1899 	if (error)
1900 		goto error_out;
1901 
1902 	nch = &nd.nl_nch;
1903 
1904 	error = priv_check_cred(td->td_ucred, PRIV_VFS_CHROOT, 0);
1905 	if (error)
1906 		goto error_out;
1907 
1908 	if ((vp = nch->ncp->nc_vp) == NULL) {
1909 		error = ENOENT;
1910 		goto error_out;
1911 	}
1912 
1913 	if ((error = cache_vref(nch, nd.nl_cred, &vp)) != 0)
1914 		goto error_out;
1915 
1916 	kprintf("chroot_kernel: set new rootnch/rootvnode to %s\n", uap->path);
1917 	vfs_cache_setroot(vp, cache_hold(nch));
1918 
1919 error_out:
1920 	nlookup_done(&nd);
1921 error_nond:
1922 	return(error);
1923 }
1924 
1925 /*
1926  * Common routine for chroot and chdir.  Given a locked, referenced vnode,
1927  * determine whether it is legal to chdir to the vnode.  The vnode's state
1928  * is not changed by this call.
1929  */
1930 static int
1931 checkvp_chdir(struct vnode *vp, struct thread *td)
1932 {
1933 	int error;
1934 
1935 	if (vp->v_type != VDIR)
1936 		error = ENOTDIR;
1937 	else
1938 		error = VOP_EACCESS(vp, VEXEC, td->td_ucred);
1939 	return (error);
1940 }
1941 
1942 int
1943 kern_open(struct nlookupdata *nd, int oflags, int mode, int *res)
1944 {
1945 	struct thread *td = curthread;
1946 	struct proc *p = td->td_proc;
1947 	struct lwp *lp = td->td_lwp;
1948 	struct filedesc *fdp = p->p_fd;
1949 	int cmode, flags;
1950 	struct file *nfp;
1951 	struct file *fp;
1952 	struct vnode *vp;
1953 	int type, indx, error = 0;
1954 	struct flock lf;
1955 
1956 	if ((oflags & O_ACCMODE) == O_ACCMODE)
1957 		return (EINVAL);
1958 	flags = FFLAGS(oflags);
1959 	error = falloc(lp, &nfp, NULL);
1960 	if (error)
1961 		return (error);
1962 	fp = nfp;
1963 	cmode = ((mode &~ fdp->fd_cmask) & ALLPERMS) & ~S_ISTXT;
1964 
1965 	/*
1966 	 * XXX p_dupfd is a real mess.  It allows a device to return a
1967 	 * file descriptor to be duplicated rather then doing the open
1968 	 * itself.
1969 	 */
1970 	lp->lwp_dupfd = -1;
1971 
1972 	/*
1973 	 * Call vn_open() to do the lookup and assign the vnode to the
1974 	 * file pointer.  vn_open() does not change the ref count on fp
1975 	 * and the vnode, on success, will be inherited by the file pointer
1976 	 * and unlocked.
1977 	 *
1978 	 * Request a shared lock on the vnode if possible.
1979 	 *
1980 	 * Executable binaries can race VTEXT against O_RDWR opens, so
1981 	 * use an exclusive lock for O_RDWR opens as well.
1982 	 *
1983 	 * NOTE: We need a flag to separate terminal vnode locking from
1984 	 *	 parent locking.  O_CREAT needs parent locking, but O_TRUNC
1985 	 *	 and O_RDWR only need to lock the terminal vnode exclusively.
1986 	 */
1987 	nd->nl_flags |= NLC_LOCKVP;
1988 	if ((flags & (O_CREAT|O_TRUNC|O_RDWR)) == 0)
1989 		nd->nl_flags |= NLC_SHAREDLOCK;
1990 
1991 	error = vn_open(nd, fp, flags, cmode);
1992 	nlookup_done(nd);
1993 
1994 	if (error) {
1995 		/*
1996 		 * handle special fdopen() case.  bleh.  dupfdopen() is
1997 		 * responsible for dropping the old contents of ofiles[indx]
1998 		 * if it succeeds.
1999 		 *
2000 		 * Note that fsetfd() will add a ref to fp which represents
2001 		 * the fd_files[] assignment.  We must still drop our
2002 		 * reference.
2003 		 */
2004 		if ((error == ENODEV || error == ENXIO) && lp->lwp_dupfd >= 0) {
2005 			if (fdalloc(p, 0, &indx) == 0) {
2006 				error = dupfdopen(fdp, indx, lp->lwp_dupfd, flags, error);
2007 				if (error == 0) {
2008 					*res = indx;
2009 					fdrop(fp);	/* our ref */
2010 					return (0);
2011 				}
2012 				fsetfd(fdp, NULL, indx);
2013 			}
2014 		}
2015 		fdrop(fp);	/* our ref */
2016 		if (error == ERESTART)
2017 			error = EINTR;
2018 		return (error);
2019 	}
2020 
2021 	/*
2022 	 * ref the vnode for ourselves so it can't be ripped out from under
2023 	 * is.  XXX need an ND flag to request that the vnode be returned
2024 	 * anyway.
2025 	 *
2026 	 * Reserve a file descriptor but do not assign it until the open
2027 	 * succeeds.
2028 	 */
2029 	vp = (struct vnode *)fp->f_data;
2030 	vref(vp);
2031 	if ((error = fdalloc(p, 0, &indx)) != 0) {
2032 		fdrop(fp);
2033 		vrele(vp);
2034 		return (error);
2035 	}
2036 
2037 	/*
2038 	 * If no error occurs the vp will have been assigned to the file
2039 	 * pointer.
2040 	 */
2041 	lp->lwp_dupfd = 0;
2042 
2043 	if (flags & (O_EXLOCK | O_SHLOCK)) {
2044 		lf.l_whence = SEEK_SET;
2045 		lf.l_start = 0;
2046 		lf.l_len = 0;
2047 		if (flags & O_EXLOCK)
2048 			lf.l_type = F_WRLCK;
2049 		else
2050 			lf.l_type = F_RDLCK;
2051 		if (flags & FNONBLOCK)
2052 			type = 0;
2053 		else
2054 			type = F_WAIT;
2055 
2056 		if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0) {
2057 			/*
2058 			 * lock request failed.  Clean up the reserved
2059 			 * descriptor.
2060 			 */
2061 			vrele(vp);
2062 			fsetfd(fdp, NULL, indx);
2063 			fdrop(fp);
2064 			return (error);
2065 		}
2066 		atomic_set_int(&fp->f_flag, FHASLOCK); /* race ok */
2067 	}
2068 #if 0
2069 	/*
2070 	 * Assert that all regular file vnodes were created with a object.
2071 	 */
2072 	KASSERT(vp->v_type != VREG || vp->v_object != NULL,
2073 		("open: regular file has no backing object after vn_open"));
2074 #endif
2075 
2076 	vrele(vp);
2077 
2078 	/*
2079 	 * release our private reference, leaving the one associated with the
2080 	 * descriptor table intact.
2081 	 */
2082 	if (oflags & O_CLOEXEC)
2083 		fdp->fd_files[indx].fileflags |= UF_EXCLOSE;
2084 	fsetfd(fdp, fp, indx);
2085 	fdrop(fp);
2086 	*res = indx;
2087 	return (error);
2088 }
2089 
2090 /*
2091  * open_args(char *path, int flags, int mode)
2092  *
2093  * Check permissions, allocate an open file structure,
2094  * and call the device open routine if any.
2095  */
2096 int
2097 sys_open(struct open_args *uap)
2098 {
2099 	struct nlookupdata nd;
2100 	int error;
2101 
2102 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2103 	if (error == 0) {
2104 		error = kern_open(&nd, uap->flags,
2105 				    uap->mode, &uap->sysmsg_result);
2106 	}
2107 	nlookup_done(&nd);
2108 	return (error);
2109 }
2110 
2111 /*
2112  * openat_args(int fd, char *path, int flags, int mode)
2113  */
2114 int
2115 sys_openat(struct openat_args *uap)
2116 {
2117 	struct nlookupdata nd;
2118 	int error;
2119 	struct file *fp;
2120 
2121 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2122 	if (error == 0) {
2123 		error = kern_open(&nd, uap->flags, uap->mode,
2124 					&uap->sysmsg_result);
2125 	}
2126 	nlookup_done_at(&nd, fp);
2127 	return (error);
2128 }
2129 
2130 int
2131 kern_mknod(struct nlookupdata *nd, int mode, int rmajor, int rminor)
2132 {
2133 	struct thread *td = curthread;
2134 	struct proc *p = td->td_proc;
2135 	struct vnode *vp;
2136 	struct vattr vattr;
2137 	int error;
2138 	int whiteout = 0;
2139 
2140 	KKASSERT(p);
2141 
2142 	VATTR_NULL(&vattr);
2143 	vattr.va_mode = (mode & ALLPERMS) &~ p->p_fd->fd_cmask;
2144 	vattr.va_rmajor = rmajor;
2145 	vattr.va_rminor = rminor;
2146 
2147 	switch (mode & S_IFMT) {
2148 	case S_IFMT:	/* used by badsect to flag bad sectors */
2149 		error = priv_check_cred(td->td_ucred, PRIV_VFS_MKNOD_BAD, 0);
2150 		vattr.va_type = VBAD;
2151 		break;
2152 	case S_IFCHR:
2153 		error = priv_check(td, PRIV_VFS_MKNOD_DEV);
2154 		vattr.va_type = VCHR;
2155 		break;
2156 	case S_IFBLK:
2157 		error = priv_check(td, PRIV_VFS_MKNOD_DEV);
2158 		vattr.va_type = VBLK;
2159 		break;
2160 	case S_IFWHT:
2161 		error = priv_check_cred(td->td_ucred, PRIV_VFS_MKNOD_WHT, 0);
2162 		whiteout = 1;
2163 		break;
2164 	case S_IFDIR:	/* special directories support for HAMMER */
2165 		error = priv_check_cred(td->td_ucred, PRIV_VFS_MKNOD_DIR, 0);
2166 		vattr.va_type = VDIR;
2167 		break;
2168 	default:
2169 		error = EINVAL;
2170 		break;
2171 	}
2172 
2173 	if (error)
2174 		return (error);
2175 
2176 	bwillinode(1);
2177 	nd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2178 	if ((error = nlookup(nd)) != 0)
2179 		return (error);
2180 	if (nd->nl_nch.ncp->nc_vp)
2181 		return (EEXIST);
2182 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2183 		return (error);
2184 
2185 	if (whiteout) {
2186 		error = VOP_NWHITEOUT(&nd->nl_nch, nd->nl_dvp,
2187 				      nd->nl_cred, NAMEI_CREATE);
2188 	} else {
2189 		vp = NULL;
2190 		error = VOP_NMKNOD(&nd->nl_nch, nd->nl_dvp,
2191 				   &vp, nd->nl_cred, &vattr);
2192 		if (error == 0)
2193 			vput(vp);
2194 	}
2195 	return (error);
2196 }
2197 
2198 /*
2199  * mknod_args(char *path, int mode, int dev)
2200  *
2201  * Create a special file.
2202  */
2203 int
2204 sys_mknod(struct mknod_args *uap)
2205 {
2206 	struct nlookupdata nd;
2207 	int error;
2208 
2209 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2210 	if (error == 0) {
2211 		error = kern_mknod(&nd, uap->mode,
2212 				   umajor(uap->dev), uminor(uap->dev));
2213 	}
2214 	nlookup_done(&nd);
2215 	return (error);
2216 }
2217 
2218 /*
2219  * mknodat_args(int fd, char *path, mode_t mode, dev_t dev)
2220  *
2221  * Create a special file.  The path is relative to the directory associated
2222  * with fd.
2223  */
2224 int
2225 sys_mknodat(struct mknodat_args *uap)
2226 {
2227 	struct nlookupdata nd;
2228 	struct file *fp;
2229 	int error;
2230 
2231 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2232 	if (error == 0) {
2233 		error = kern_mknod(&nd, uap->mode,
2234 				   umajor(uap->dev), uminor(uap->dev));
2235 	}
2236 	nlookup_done_at(&nd, fp);
2237 	return (error);
2238 }
2239 
2240 int
2241 kern_mkfifo(struct nlookupdata *nd, int mode)
2242 {
2243 	struct thread *td = curthread;
2244 	struct proc *p = td->td_proc;
2245 	struct vattr vattr;
2246 	struct vnode *vp;
2247 	int error;
2248 
2249 	bwillinode(1);
2250 
2251 	nd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2252 	if ((error = nlookup(nd)) != 0)
2253 		return (error);
2254 	if (nd->nl_nch.ncp->nc_vp)
2255 		return (EEXIST);
2256 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2257 		return (error);
2258 
2259 	VATTR_NULL(&vattr);
2260 	vattr.va_type = VFIFO;
2261 	vattr.va_mode = (mode & ALLPERMS) &~ p->p_fd->fd_cmask;
2262 	vp = NULL;
2263 	error = VOP_NMKNOD(&nd->nl_nch, nd->nl_dvp, &vp, nd->nl_cred, &vattr);
2264 	if (error == 0)
2265 		vput(vp);
2266 	return (error);
2267 }
2268 
2269 /*
2270  * mkfifo_args(char *path, int mode)
2271  *
2272  * Create a named pipe.
2273  */
2274 int
2275 sys_mkfifo(struct mkfifo_args *uap)
2276 {
2277 	struct nlookupdata nd;
2278 	int error;
2279 
2280 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2281 	if (error == 0)
2282 		error = kern_mkfifo(&nd, uap->mode);
2283 	nlookup_done(&nd);
2284 	return (error);
2285 }
2286 
2287 /*
2288  * mkfifoat_args(int fd, char *path, mode_t mode)
2289  *
2290  * Create a named pipe.  The path is relative to the directory associated
2291  * with fd.
2292  */
2293 int
2294 sys_mkfifoat(struct mkfifoat_args *uap)
2295 {
2296 	struct nlookupdata nd;
2297 	struct file *fp;
2298 	int error;
2299 
2300 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2301 	if (error == 0)
2302 		error = kern_mkfifo(&nd, uap->mode);
2303 	nlookup_done_at(&nd, fp);
2304 	return (error);
2305 }
2306 
2307 static int hardlink_check_uid = 0;
2308 SYSCTL_INT(_security, OID_AUTO, hardlink_check_uid, CTLFLAG_RW,
2309     &hardlink_check_uid, 0,
2310     "Unprivileged processes cannot create hard links to files owned by other "
2311     "users");
2312 static int hardlink_check_gid = 0;
2313 SYSCTL_INT(_security, OID_AUTO, hardlink_check_gid, CTLFLAG_RW,
2314     &hardlink_check_gid, 0,
2315     "Unprivileged processes cannot create hard links to files owned by other "
2316     "groups");
2317 
2318 static int
2319 can_hardlink(struct vnode *vp, struct thread *td, struct ucred *cred)
2320 {
2321 	struct vattr va;
2322 	int error;
2323 
2324 	/*
2325 	 * Shortcut if disabled
2326 	 */
2327 	if (hardlink_check_uid == 0 && hardlink_check_gid == 0)
2328 		return (0);
2329 
2330 	/*
2331 	 * Privileged user can always hardlink
2332 	 */
2333 	if (priv_check_cred(cred, PRIV_VFS_LINK, 0) == 0)
2334 		return (0);
2335 
2336 	/*
2337 	 * Otherwise only if the originating file is owned by the
2338 	 * same user or group.  Note that any group is allowed if
2339 	 * the file is owned by the caller.
2340 	 */
2341 	error = VOP_GETATTR(vp, &va);
2342 	if (error != 0)
2343 		return (error);
2344 
2345 	if (hardlink_check_uid) {
2346 		if (cred->cr_uid != va.va_uid)
2347 			return (EPERM);
2348 	}
2349 
2350 	if (hardlink_check_gid) {
2351 		if (cred->cr_uid != va.va_uid && !groupmember(va.va_gid, cred))
2352 			return (EPERM);
2353 	}
2354 
2355 	return (0);
2356 }
2357 
2358 int
2359 kern_link(struct nlookupdata *nd, struct nlookupdata *linknd)
2360 {
2361 	struct thread *td = curthread;
2362 	struct vnode *vp;
2363 	int error;
2364 
2365 	/*
2366 	 * Lookup the source and obtained a locked vnode.
2367 	 *
2368 	 * You may only hardlink a file which you have write permission
2369 	 * on or which you own.
2370 	 *
2371 	 * XXX relookup on vget failure / race ?
2372 	 */
2373 	bwillinode(1);
2374 	nd->nl_flags |= NLC_WRITE | NLC_OWN | NLC_HLINK;
2375 	if ((error = nlookup(nd)) != 0)
2376 		return (error);
2377 	vp = nd->nl_nch.ncp->nc_vp;
2378 	KKASSERT(vp != NULL);
2379 	if (vp->v_type == VDIR)
2380 		return (EPERM);		/* POSIX */
2381 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2382 		return (error);
2383 	if ((error = vget(vp, LK_EXCLUSIVE)) != 0)
2384 		return (error);
2385 
2386 	/*
2387 	 * Unlock the source so we can lookup the target without deadlocking
2388 	 * (XXX vp is locked already, possible other deadlock?).  The target
2389 	 * must not exist.
2390 	 */
2391 	KKASSERT(nd->nl_flags & NLC_NCPISLOCKED);
2392 	nd->nl_flags &= ~NLC_NCPISLOCKED;
2393 	cache_unlock(&nd->nl_nch);
2394 	vn_unlock(vp);
2395 
2396 	linknd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2397 	if ((error = nlookup(linknd)) != 0) {
2398 		vrele(vp);
2399 		return (error);
2400 	}
2401 	if (linknd->nl_nch.ncp->nc_vp) {
2402 		vrele(vp);
2403 		return (EEXIST);
2404 	}
2405 	error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_FAILRECLAIM);
2406 	if (error) {
2407 		vrele(vp);
2408 		return (error);
2409 	}
2410 
2411 	/*
2412 	 * Finally run the new API VOP.
2413 	 */
2414 	error = can_hardlink(vp, td, td->td_ucred);
2415 	if (error == 0) {
2416 		error = VOP_NLINK(&linknd->nl_nch, linknd->nl_dvp,
2417 				  vp, linknd->nl_cred);
2418 	}
2419 	vput(vp);
2420 	return (error);
2421 }
2422 
2423 /*
2424  * link_args(char *path, char *link)
2425  *
2426  * Make a hard file link.
2427  */
2428 int
2429 sys_link(struct link_args *uap)
2430 {
2431 	struct nlookupdata nd, linknd;
2432 	int error;
2433 
2434 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2435 	if (error == 0) {
2436 		error = nlookup_init(&linknd, uap->link, UIO_USERSPACE, 0);
2437 		if (error == 0)
2438 			error = kern_link(&nd, &linknd);
2439 		nlookup_done(&linknd);
2440 	}
2441 	nlookup_done(&nd);
2442 	return (error);
2443 }
2444 
2445 /*
2446  * linkat_args(int fd1, char *path1, int fd2, char *path2, int flags)
2447  *
2448  * Make a hard file link. The path1 argument is relative to the directory
2449  * associated with fd1, and similarly the path2 argument is relative to
2450  * the directory associated with fd2.
2451  */
2452 int
2453 sys_linkat(struct linkat_args *uap)
2454 {
2455 	struct nlookupdata nd, linknd;
2456 	struct file *fp1, *fp2;
2457 	int error;
2458 
2459 	error = nlookup_init_at(&nd, &fp1, uap->fd1, uap->path1, UIO_USERSPACE,
2460 	    (uap->flags & AT_SYMLINK_FOLLOW) ? NLC_FOLLOW : 0);
2461 	if (error == 0) {
2462 		error = nlookup_init_at(&linknd, &fp2, uap->fd2,
2463 		    uap->path2, UIO_USERSPACE, 0);
2464 		if (error == 0)
2465 			error = kern_link(&nd, &linknd);
2466 		nlookup_done_at(&linknd, fp2);
2467 	}
2468 	nlookup_done_at(&nd, fp1);
2469 	return (error);
2470 }
2471 
2472 int
2473 kern_symlink(struct nlookupdata *nd, char *path, int mode)
2474 {
2475 	struct vattr vattr;
2476 	struct vnode *vp;
2477 	struct vnode *dvp;
2478 	int error;
2479 
2480 	bwillinode(1);
2481 	nd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2482 	if ((error = nlookup(nd)) != 0)
2483 		return (error);
2484 	if (nd->nl_nch.ncp->nc_vp)
2485 		return (EEXIST);
2486 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2487 		return (error);
2488 	dvp = nd->nl_dvp;
2489 	VATTR_NULL(&vattr);
2490 	vattr.va_mode = mode;
2491 	error = VOP_NSYMLINK(&nd->nl_nch, dvp, &vp, nd->nl_cred, &vattr, path);
2492 	if (error == 0)
2493 		vput(vp);
2494 	return (error);
2495 }
2496 
2497 /*
2498  * symlink(char *path, char *link)
2499  *
2500  * Make a symbolic link.
2501  */
2502 int
2503 sys_symlink(struct symlink_args *uap)
2504 {
2505 	struct thread *td = curthread;
2506 	struct nlookupdata nd;
2507 	char *path;
2508 	int error;
2509 	int mode;
2510 
2511 	path = objcache_get(namei_oc, M_WAITOK);
2512 	error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
2513 	if (error == 0) {
2514 		error = nlookup_init(&nd, uap->link, UIO_USERSPACE, 0);
2515 		if (error == 0) {
2516 			mode = ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask;
2517 			error = kern_symlink(&nd, path, mode);
2518 		}
2519 		nlookup_done(&nd);
2520 	}
2521 	objcache_put(namei_oc, path);
2522 	return (error);
2523 }
2524 
2525 /*
2526  * symlinkat_args(char *path1, int fd, char *path2)
2527  *
2528  * Make a symbolic link.  The path2 argument is relative to the directory
2529  * associated with fd.
2530  */
2531 int
2532 sys_symlinkat(struct symlinkat_args *uap)
2533 {
2534 	struct thread *td = curthread;
2535 	struct nlookupdata nd;
2536 	struct file *fp;
2537 	char *path1;
2538 	int error;
2539 	int mode;
2540 
2541 	path1 = objcache_get(namei_oc, M_WAITOK);
2542 	error = copyinstr(uap->path1, path1, MAXPATHLEN, NULL);
2543 	if (error == 0) {
2544 		error = nlookup_init_at(&nd, &fp, uap->fd, uap->path2,
2545 		    UIO_USERSPACE, 0);
2546 		if (error == 0) {
2547 			mode = ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask;
2548 			error = kern_symlink(&nd, path1, mode);
2549 		}
2550 		nlookup_done_at(&nd, fp);
2551 	}
2552 	objcache_put(namei_oc, path1);
2553 	return (error);
2554 }
2555 
2556 /*
2557  * undelete_args(char *path)
2558  *
2559  * Delete a whiteout from the filesystem.
2560  */
2561 int
2562 sys_undelete(struct undelete_args *uap)
2563 {
2564 	struct nlookupdata nd;
2565 	int error;
2566 
2567 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2568 	bwillinode(1);
2569 	nd.nl_flags |= NLC_DELETE | NLC_REFDVP;
2570 	if (error == 0)
2571 		error = nlookup(&nd);
2572 	if (error == 0)
2573 		error = ncp_writechk(&nd.nl_nch);
2574 	if (error == 0) {
2575 		error = VOP_NWHITEOUT(&nd.nl_nch, nd.nl_dvp, nd.nl_cred,
2576 				      NAMEI_DELETE);
2577 	}
2578 	nlookup_done(&nd);
2579 	return (error);
2580 }
2581 
2582 int
2583 kern_unlink(struct nlookupdata *nd)
2584 {
2585 	int error;
2586 
2587 	bwillinode(1);
2588 	nd->nl_flags |= NLC_DELETE | NLC_REFDVP;
2589 	if ((error = nlookup(nd)) != 0)
2590 		return (error);
2591 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2592 		return (error);
2593 	error = VOP_NREMOVE(&nd->nl_nch, nd->nl_dvp, nd->nl_cred);
2594 	return (error);
2595 }
2596 
2597 /*
2598  * unlink_args(char *path)
2599  *
2600  * Delete a name from the filesystem.
2601  */
2602 int
2603 sys_unlink(struct unlink_args *uap)
2604 {
2605 	struct nlookupdata nd;
2606 	int error;
2607 
2608 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2609 	if (error == 0)
2610 		error = kern_unlink(&nd);
2611 	nlookup_done(&nd);
2612 	return (error);
2613 }
2614 
2615 
2616 /*
2617  * unlinkat_args(int fd, char *path, int flags)
2618  *
2619  * Delete the file or directory entry pointed to by fd/path.
2620  */
2621 int
2622 sys_unlinkat(struct unlinkat_args *uap)
2623 {
2624 	struct nlookupdata nd;
2625 	struct file *fp;
2626 	int error;
2627 
2628 	if (uap->flags & ~AT_REMOVEDIR)
2629 		return (EINVAL);
2630 
2631 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2632 	if (error == 0) {
2633 		if (uap->flags & AT_REMOVEDIR)
2634 			error = kern_rmdir(&nd);
2635 		else
2636 			error = kern_unlink(&nd);
2637 	}
2638 	nlookup_done_at(&nd, fp);
2639 	return (error);
2640 }
2641 
2642 int
2643 kern_lseek(int fd, off_t offset, int whence, off_t *res)
2644 {
2645 	struct thread *td = curthread;
2646 	struct proc *p = td->td_proc;
2647 	struct file *fp;
2648 	struct vnode *vp;
2649 	struct vattr vattr;
2650 	off_t new_offset;
2651 	int error;
2652 
2653 	fp = holdfp(p->p_fd, fd, -1);
2654 	if (fp == NULL)
2655 		return (EBADF);
2656 	if (fp->f_type != DTYPE_VNODE) {
2657 		error = ESPIPE;
2658 		goto done;
2659 	}
2660 	vp = (struct vnode *)fp->f_data;
2661 
2662 	switch (whence) {
2663 	case L_INCR:
2664 		spin_lock(&fp->f_spin);
2665 		new_offset = fp->f_offset + offset;
2666 		error = 0;
2667 		break;
2668 	case L_XTND:
2669 		error = VOP_GETATTR(vp, &vattr);
2670 		spin_lock(&fp->f_spin);
2671 		new_offset = offset + vattr.va_size;
2672 		break;
2673 	case L_SET:
2674 		new_offset = offset;
2675 		error = 0;
2676 		spin_lock(&fp->f_spin);
2677 		break;
2678 	default:
2679 		new_offset = 0;
2680 		error = EINVAL;
2681 		spin_lock(&fp->f_spin);
2682 		break;
2683 	}
2684 
2685 	/*
2686 	 * Validate the seek position.  Negative offsets are not allowed
2687 	 * for regular files or directories.
2688 	 *
2689 	 * Normally we would also not want to allow negative offsets for
2690 	 * character and block-special devices.  However kvm addresses
2691 	 * on 64 bit architectures might appear to be negative and must
2692 	 * be allowed.
2693 	 */
2694 	if (error == 0) {
2695 		if (new_offset < 0 &&
2696 		    (vp->v_type == VREG || vp->v_type == VDIR)) {
2697 			error = EINVAL;
2698 		} else {
2699 			fp->f_offset = new_offset;
2700 		}
2701 	}
2702 	*res = fp->f_offset;
2703 	spin_unlock(&fp->f_spin);
2704 done:
2705 	fdrop(fp);
2706 	return (error);
2707 }
2708 
2709 /*
2710  * lseek_args(int fd, int pad, off_t offset, int whence)
2711  *
2712  * Reposition read/write file offset.
2713  */
2714 int
2715 sys_lseek(struct lseek_args *uap)
2716 {
2717 	int error;
2718 
2719 	error = kern_lseek(uap->fd, uap->offset, uap->whence,
2720 			   &uap->sysmsg_offset);
2721 
2722 	return (error);
2723 }
2724 
2725 /*
2726  * Check if current process can access given file.  amode is a bitmask of *_OK
2727  * access bits.  flags is a bitmask of AT_* flags.
2728  */
2729 int
2730 kern_access(struct nlookupdata *nd, int amode, int flags)
2731 {
2732 	struct vnode *vp;
2733 	int error, mode;
2734 
2735 	if (flags & ~AT_EACCESS)
2736 		return (EINVAL);
2737 	nd->nl_flags |= NLC_SHAREDLOCK;
2738 	if ((error = nlookup(nd)) != 0)
2739 		return (error);
2740 retry:
2741 	error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_SHARED, &vp);
2742 	if (error)
2743 		return (error);
2744 
2745 	/* Flags == 0 means only check for existence. */
2746 	if (amode) {
2747 		mode = 0;
2748 		if (amode & R_OK)
2749 			mode |= VREAD;
2750 		if (amode & W_OK)
2751 			mode |= VWRITE;
2752 		if (amode & X_OK)
2753 			mode |= VEXEC;
2754 		if ((mode & VWRITE) == 0 ||
2755 		    (error = vn_writechk(vp, &nd->nl_nch)) == 0)
2756 			error = VOP_ACCESS_FLAGS(vp, mode, flags, nd->nl_cred);
2757 
2758 		/*
2759 		 * If the file handle is stale we have to re-resolve the
2760 		 * entry with the ncp held exclusively.  This is a hack
2761 		 * at the moment.
2762 		 */
2763 		if (error == ESTALE) {
2764 			vput(vp);
2765 			cache_unlock(&nd->nl_nch);
2766 			cache_lock(&nd->nl_nch);
2767 			cache_setunresolved(&nd->nl_nch);
2768 			error = cache_resolve(&nd->nl_nch, nd->nl_cred);
2769 			if (error == 0) {
2770 				vp = NULL;
2771 				goto retry;
2772 			}
2773 			return(error);
2774 		}
2775 	}
2776 	vput(vp);
2777 	return (error);
2778 }
2779 
2780 /*
2781  * access_args(char *path, int flags)
2782  *
2783  * Check access permissions.
2784  */
2785 int
2786 sys_access(struct access_args *uap)
2787 {
2788 	struct nlookupdata nd;
2789 	int error;
2790 
2791 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2792 	if (error == 0)
2793 		error = kern_access(&nd, uap->flags, 0);
2794 	nlookup_done(&nd);
2795 	return (error);
2796 }
2797 
2798 
2799 /*
2800  * eaccess_args(char *path, int flags)
2801  *
2802  * Check access permissions.
2803  */
2804 int
2805 sys_eaccess(struct eaccess_args *uap)
2806 {
2807 	struct nlookupdata nd;
2808 	int error;
2809 
2810 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2811 	if (error == 0)
2812 		error = kern_access(&nd, uap->flags, AT_EACCESS);
2813 	nlookup_done(&nd);
2814 	return (error);
2815 }
2816 
2817 
2818 /*
2819  * faccessat_args(int fd, char *path, int amode, int flags)
2820  *
2821  * Check access permissions.
2822  */
2823 int
2824 sys_faccessat(struct faccessat_args *uap)
2825 {
2826 	struct nlookupdata nd;
2827 	struct file *fp;
2828 	int error;
2829 
2830 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE,
2831 				NLC_FOLLOW);
2832 	if (error == 0)
2833 		error = kern_access(&nd, uap->amode, uap->flags);
2834 	nlookup_done_at(&nd, fp);
2835 	return (error);
2836 }
2837 
2838 int
2839 kern_stat(struct nlookupdata *nd, struct stat *st)
2840 {
2841 	int error;
2842 	struct vnode *vp;
2843 
2844 	nd->nl_flags |= NLC_SHAREDLOCK;
2845 	if ((error = nlookup(nd)) != 0)
2846 		return (error);
2847 again:
2848 	if ((vp = nd->nl_nch.ncp->nc_vp) == NULL)
2849 		return (ENOENT);
2850 
2851 	if ((error = vget(vp, LK_SHARED)) != 0)
2852 		return (error);
2853 	error = vn_stat(vp, st, nd->nl_cred);
2854 
2855 	/*
2856 	 * If the file handle is stale we have to re-resolve the
2857 	 * entry with the ncp held exclusively.  This is a hack
2858 	 * at the moment.
2859 	 */
2860 	if (error == ESTALE) {
2861 		vput(vp);
2862 		cache_unlock(&nd->nl_nch);
2863 		cache_lock(&nd->nl_nch);
2864 		cache_setunresolved(&nd->nl_nch);
2865 		error = cache_resolve(&nd->nl_nch, nd->nl_cred);
2866 		if (error == 0)
2867 			goto again;
2868 	} else {
2869 		vput(vp);
2870 	}
2871 	return (error);
2872 }
2873 
2874 /*
2875  * stat_args(char *path, struct stat *ub)
2876  *
2877  * Get file status; this version follows links.
2878  */
2879 int
2880 sys_stat(struct stat_args *uap)
2881 {
2882 	struct nlookupdata nd;
2883 	struct stat st;
2884 	int error;
2885 
2886 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2887 	if (error == 0) {
2888 		error = kern_stat(&nd, &st);
2889 		if (error == 0)
2890 			error = copyout(&st, uap->ub, sizeof(*uap->ub));
2891 	}
2892 	nlookup_done(&nd);
2893 	return (error);
2894 }
2895 
2896 /*
2897  * lstat_args(char *path, struct stat *ub)
2898  *
2899  * Get file status; this version does not follow links.
2900  */
2901 int
2902 sys_lstat(struct lstat_args *uap)
2903 {
2904 	struct nlookupdata nd;
2905 	struct stat st;
2906 	int error;
2907 
2908 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2909 	if (error == 0) {
2910 		error = kern_stat(&nd, &st);
2911 		if (error == 0)
2912 			error = copyout(&st, uap->ub, sizeof(*uap->ub));
2913 	}
2914 	nlookup_done(&nd);
2915 	return (error);
2916 }
2917 
2918 /*
2919  * fstatat_args(int fd, char *path, struct stat *sb, int flags)
2920  *
2921  * Get status of file pointed to by fd/path.
2922  */
2923 int
2924 sys_fstatat(struct fstatat_args *uap)
2925 {
2926 	struct nlookupdata nd;
2927 	struct stat st;
2928 	int error;
2929 	int flags;
2930 	struct file *fp;
2931 
2932 	if (uap->flags & ~AT_SYMLINK_NOFOLLOW)
2933 		return (EINVAL);
2934 
2935 	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
2936 
2937 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path,
2938 				UIO_USERSPACE, flags);
2939 	if (error == 0) {
2940 		error = kern_stat(&nd, &st);
2941 		if (error == 0)
2942 			error = copyout(&st, uap->sb, sizeof(*uap->sb));
2943 	}
2944 	nlookup_done_at(&nd, fp);
2945 	return (error);
2946 }
2947 
2948 static int
2949 kern_pathconf(char *path, int name, int flags, register_t *sysmsg_regp)
2950 {
2951 	struct nlookupdata nd;
2952 	struct vnode *vp;
2953 	int error;
2954 
2955 	vp = NULL;
2956 	error = nlookup_init(&nd, path, UIO_USERSPACE, flags);
2957 	if (error == 0)
2958 		error = nlookup(&nd);
2959 	if (error == 0)
2960 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
2961 	nlookup_done(&nd);
2962 	if (error == 0) {
2963 		error = VOP_PATHCONF(vp, name, sysmsg_regp);
2964 		vput(vp);
2965 	}
2966 	return (error);
2967 }
2968 
2969 /*
2970  * pathconf_Args(char *path, int name)
2971  *
2972  * Get configurable pathname variables.
2973  */
2974 int
2975 sys_pathconf(struct pathconf_args *uap)
2976 {
2977 	return (kern_pathconf(uap->path, uap->name, NLC_FOLLOW,
2978 		&uap->sysmsg_reg));
2979 }
2980 
2981 /*
2982  * lpathconf_Args(char *path, int name)
2983  *
2984  * Get configurable pathname variables, but don't follow symlinks.
2985  */
2986 int
2987 sys_lpathconf(struct lpathconf_args *uap)
2988 {
2989 	return (kern_pathconf(uap->path, uap->name, 0, &uap->sysmsg_reg));
2990 }
2991 
2992 /*
2993  * XXX: daver
2994  * kern_readlink isn't properly split yet.  There is a copyin burried
2995  * in VOP_READLINK().
2996  */
2997 int
2998 kern_readlink(struct nlookupdata *nd, char *buf, int count, int *res)
2999 {
3000 	struct thread *td = curthread;
3001 	struct vnode *vp;
3002 	struct iovec aiov;
3003 	struct uio auio;
3004 	int error;
3005 
3006 	nd->nl_flags |= NLC_SHAREDLOCK;
3007 	if ((error = nlookup(nd)) != 0)
3008 		return (error);
3009 	error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_SHARED, &vp);
3010 	if (error)
3011 		return (error);
3012 	if (vp->v_type != VLNK) {
3013 		error = EINVAL;
3014 	} else {
3015 		aiov.iov_base = buf;
3016 		aiov.iov_len = count;
3017 		auio.uio_iov = &aiov;
3018 		auio.uio_iovcnt = 1;
3019 		auio.uio_offset = 0;
3020 		auio.uio_rw = UIO_READ;
3021 		auio.uio_segflg = UIO_USERSPACE;
3022 		auio.uio_td = td;
3023 		auio.uio_resid = count;
3024 		error = VOP_READLINK(vp, &auio, td->td_ucred);
3025 	}
3026 	vput(vp);
3027 	*res = count - auio.uio_resid;
3028 	return (error);
3029 }
3030 
3031 /*
3032  * readlink_args(char *path, char *buf, int count)
3033  *
3034  * Return target name of a symbolic link.
3035  */
3036 int
3037 sys_readlink(struct readlink_args *uap)
3038 {
3039 	struct nlookupdata nd;
3040 	int error;
3041 
3042 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3043 	if (error == 0) {
3044 		error = kern_readlink(&nd, uap->buf, uap->count,
3045 					&uap->sysmsg_result);
3046 	}
3047 	nlookup_done(&nd);
3048 	return (error);
3049 }
3050 
3051 /*
3052  * readlinkat_args(int fd, char *path, char *buf, size_t bufsize)
3053  *
3054  * Return target name of a symbolic link.  The path is relative to the
3055  * directory associated with fd.
3056  */
3057 int
3058 sys_readlinkat(struct readlinkat_args *uap)
3059 {
3060 	struct nlookupdata nd;
3061 	struct file *fp;
3062 	int error;
3063 
3064 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
3065 	if (error == 0) {
3066 		error = kern_readlink(&nd, uap->buf, uap->bufsize,
3067 					&uap->sysmsg_result);
3068 	}
3069 	nlookup_done_at(&nd, fp);
3070 	return (error);
3071 }
3072 
3073 static int
3074 setfflags(struct vnode *vp, int flags)
3075 {
3076 	struct thread *td = curthread;
3077 	int error;
3078 	struct vattr vattr;
3079 
3080 	/*
3081 	 * Prevent non-root users from setting flags on devices.  When
3082 	 * a device is reused, users can retain ownership of the device
3083 	 * if they are allowed to set flags and programs assume that
3084 	 * chown can't fail when done as root.
3085 	 */
3086 	if ((vp->v_type == VCHR || vp->v_type == VBLK) &&
3087 	    ((error = priv_check_cred(td->td_ucred, PRIV_VFS_CHFLAGS_DEV, 0)) != 0))
3088 		return (error);
3089 
3090 	/*
3091 	 * note: vget is required for any operation that might mod the vnode
3092 	 * so VINACTIVE is properly cleared.
3093 	 */
3094 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
3095 		VATTR_NULL(&vattr);
3096 		vattr.va_flags = flags;
3097 		error = VOP_SETATTR(vp, &vattr, td->td_ucred);
3098 		vput(vp);
3099 	}
3100 	return (error);
3101 }
3102 
3103 /*
3104  * chflags(char *path, int flags)
3105  *
3106  * Change flags of a file given a path name.
3107  */
3108 int
3109 sys_chflags(struct chflags_args *uap)
3110 {
3111 	struct nlookupdata nd;
3112 	struct vnode *vp;
3113 	int error;
3114 
3115 	vp = NULL;
3116 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3117 	if (error == 0)
3118 		error = nlookup(&nd);
3119 	if (error == 0)
3120 		error = ncp_writechk(&nd.nl_nch);
3121 	if (error == 0)
3122 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
3123 	nlookup_done(&nd);
3124 	if (error == 0) {
3125 		error = setfflags(vp, uap->flags);
3126 		vrele(vp);
3127 	}
3128 	return (error);
3129 }
3130 
3131 /*
3132  * lchflags(char *path, int flags)
3133  *
3134  * Change flags of a file given a path name, but don't follow symlinks.
3135  */
3136 int
3137 sys_lchflags(struct lchflags_args *uap)
3138 {
3139 	struct nlookupdata nd;
3140 	struct vnode *vp;
3141 	int error;
3142 
3143 	vp = NULL;
3144 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3145 	if (error == 0)
3146 		error = nlookup(&nd);
3147 	if (error == 0)
3148 		error = ncp_writechk(&nd.nl_nch);
3149 	if (error == 0)
3150 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
3151 	nlookup_done(&nd);
3152 	if (error == 0) {
3153 		error = setfflags(vp, uap->flags);
3154 		vrele(vp);
3155 	}
3156 	return (error);
3157 }
3158 
3159 /*
3160  * fchflags_args(int fd, int flags)
3161  *
3162  * Change flags of a file given a file descriptor.
3163  */
3164 int
3165 sys_fchflags(struct fchflags_args *uap)
3166 {
3167 	struct thread *td = curthread;
3168 	struct proc *p = td->td_proc;
3169 	struct file *fp;
3170 	int error;
3171 
3172 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
3173 		return (error);
3174 	if (fp->f_nchandle.ncp)
3175 		error = ncp_writechk(&fp->f_nchandle);
3176 	if (error == 0)
3177 		error = setfflags((struct vnode *) fp->f_data, uap->flags);
3178 	fdrop(fp);
3179 	return (error);
3180 }
3181 
3182 /*
3183  * chflagsat_args(int fd, const char *path, int flags, int atflags)
3184  * change flags given a pathname relative to a filedescriptor
3185  */
3186 int sys_chflagsat(struct chflagsat_args *uap)
3187 {
3188 	struct nlookupdata nd;
3189 	struct vnode *vp;
3190 	struct file *fp;
3191 	int error;
3192 	int lookupflags;
3193 
3194 	if (uap->atflags & ~AT_SYMLINK_NOFOLLOW)
3195 		return (EINVAL);
3196 
3197 	lookupflags = (uap->atflags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
3198 
3199 	vp = NULL;
3200 	error = nlookup_init_at(&nd, &fp, uap->fd,  uap->path, UIO_USERSPACE, lookupflags);
3201 	if (error == 0)
3202 		error = nlookup(&nd);
3203 	if (error == 0)
3204 		error = ncp_writechk(&nd.nl_nch);
3205 	if (error == 0)
3206 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
3207 	nlookup_done_at(&nd, fp);
3208 	if (error == 0) {
3209 		error = setfflags(vp, uap->flags);
3210 		vrele(vp);
3211 	}
3212 	return (error);
3213 }
3214 
3215 
3216 static int
3217 setfmode(struct vnode *vp, int mode)
3218 {
3219 	struct thread *td = curthread;
3220 	int error;
3221 	struct vattr vattr;
3222 
3223 	/*
3224 	 * note: vget is required for any operation that might mod the vnode
3225 	 * so VINACTIVE is properly cleared.
3226 	 */
3227 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
3228 		VATTR_NULL(&vattr);
3229 		vattr.va_mode = mode & ALLPERMS;
3230 		error = VOP_SETATTR(vp, &vattr, td->td_ucred);
3231 		cache_inval_wxok(vp);
3232 		vput(vp);
3233 	}
3234 	return error;
3235 }
3236 
3237 int
3238 kern_chmod(struct nlookupdata *nd, int mode)
3239 {
3240 	struct vnode *vp;
3241 	int error;
3242 
3243 	if ((error = nlookup(nd)) != 0)
3244 		return (error);
3245 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
3246 		return (error);
3247 	if ((error = ncp_writechk(&nd->nl_nch)) == 0)
3248 		error = setfmode(vp, mode);
3249 	vrele(vp);
3250 	return (error);
3251 }
3252 
3253 /*
3254  * chmod_args(char *path, int mode)
3255  *
3256  * Change mode of a file given path name.
3257  */
3258 int
3259 sys_chmod(struct chmod_args *uap)
3260 {
3261 	struct nlookupdata nd;
3262 	int error;
3263 
3264 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3265 	if (error == 0)
3266 		error = kern_chmod(&nd, uap->mode);
3267 	nlookup_done(&nd);
3268 	return (error);
3269 }
3270 
3271 /*
3272  * lchmod_args(char *path, int mode)
3273  *
3274  * Change mode of a file given path name (don't follow links.)
3275  */
3276 int
3277 sys_lchmod(struct lchmod_args *uap)
3278 {
3279 	struct nlookupdata nd;
3280 	int error;
3281 
3282 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3283 	if (error == 0)
3284 		error = kern_chmod(&nd, uap->mode);
3285 	nlookup_done(&nd);
3286 	return (error);
3287 }
3288 
3289 /*
3290  * fchmod_args(int fd, int mode)
3291  *
3292  * Change mode of a file given a file descriptor.
3293  */
3294 int
3295 sys_fchmod(struct fchmod_args *uap)
3296 {
3297 	struct thread *td = curthread;
3298 	struct proc *p = td->td_proc;
3299 	struct file *fp;
3300 	int error;
3301 
3302 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
3303 		return (error);
3304 	if (fp->f_nchandle.ncp)
3305 		error = ncp_writechk(&fp->f_nchandle);
3306 	if (error == 0)
3307 		error = setfmode((struct vnode *)fp->f_data, uap->mode);
3308 	fdrop(fp);
3309 	return (error);
3310 }
3311 
3312 /*
3313  * fchmodat_args(char *path, int mode)
3314  *
3315  * Change mode of a file pointed to by fd/path.
3316  */
3317 int
3318 sys_fchmodat(struct fchmodat_args *uap)
3319 {
3320 	struct nlookupdata nd;
3321 	struct file *fp;
3322 	int error;
3323 	int flags;
3324 
3325 	if (uap->flags & ~AT_SYMLINK_NOFOLLOW)
3326 		return (EINVAL);
3327 	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
3328 
3329 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path,
3330 				UIO_USERSPACE, flags);
3331 	if (error == 0)
3332 		error = kern_chmod(&nd, uap->mode);
3333 	nlookup_done_at(&nd, fp);
3334 	return (error);
3335 }
3336 
3337 static int
3338 setfown(struct mount *mp, struct vnode *vp, uid_t uid, gid_t gid)
3339 {
3340 	struct thread *td = curthread;
3341 	int error;
3342 	struct vattr vattr;
3343 	uid_t o_uid;
3344 	gid_t o_gid;
3345 	uint64_t size;
3346 
3347 	/*
3348 	 * note: vget is required for any operation that might mod the vnode
3349 	 * so VINACTIVE is properly cleared.
3350 	 */
3351 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
3352 		if ((error = VOP_GETATTR(vp, &vattr)) != 0)
3353 			return error;
3354 		o_uid = vattr.va_uid;
3355 		o_gid = vattr.va_gid;
3356 		size = vattr.va_size;
3357 
3358 		VATTR_NULL(&vattr);
3359 		vattr.va_uid = uid;
3360 		vattr.va_gid = gid;
3361 		error = VOP_SETATTR(vp, &vattr, td->td_ucred);
3362 		vput(vp);
3363 	}
3364 
3365 	if (error == 0) {
3366 		if (uid == -1)
3367 			uid = o_uid;
3368 		if (gid == -1)
3369 			gid = o_gid;
3370 		VFS_ACCOUNT(mp, o_uid, o_gid, -size);
3371 		VFS_ACCOUNT(mp,   uid,   gid,  size);
3372 	}
3373 
3374 	return error;
3375 }
3376 
3377 int
3378 kern_chown(struct nlookupdata *nd, int uid, int gid)
3379 {
3380 	struct vnode *vp;
3381 	int error;
3382 
3383 	if ((error = nlookup(nd)) != 0)
3384 		return (error);
3385 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
3386 		return (error);
3387 	if ((error = ncp_writechk(&nd->nl_nch)) == 0)
3388 		error = setfown(nd->nl_nch.mount, vp, uid, gid);
3389 	vrele(vp);
3390 	return (error);
3391 }
3392 
3393 /*
3394  * chown(char *path, int uid, int gid)
3395  *
3396  * Set ownership given a path name.
3397  */
3398 int
3399 sys_chown(struct chown_args *uap)
3400 {
3401 	struct nlookupdata nd;
3402 	int error;
3403 
3404 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3405 	if (error == 0)
3406 		error = kern_chown(&nd, uap->uid, uap->gid);
3407 	nlookup_done(&nd);
3408 	return (error);
3409 }
3410 
3411 /*
3412  * lchown_args(char *path, int uid, int gid)
3413  *
3414  * Set ownership given a path name, do not cross symlinks.
3415  */
3416 int
3417 sys_lchown(struct lchown_args *uap)
3418 {
3419 	struct nlookupdata nd;
3420 	int error;
3421 
3422 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3423 	if (error == 0)
3424 		error = kern_chown(&nd, uap->uid, uap->gid);
3425 	nlookup_done(&nd);
3426 	return (error);
3427 }
3428 
3429 /*
3430  * fchown_args(int fd, int uid, int gid)
3431  *
3432  * Set ownership given a file descriptor.
3433  */
3434 int
3435 sys_fchown(struct fchown_args *uap)
3436 {
3437 	struct thread *td = curthread;
3438 	struct proc *p = td->td_proc;
3439 	struct file *fp;
3440 	int error;
3441 
3442 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
3443 		return (error);
3444 	if (fp->f_nchandle.ncp)
3445 		error = ncp_writechk(&fp->f_nchandle);
3446 	if (error == 0)
3447 		error = setfown(p->p_fd->fd_ncdir.mount,
3448 			(struct vnode *)fp->f_data, uap->uid, uap->gid);
3449 	fdrop(fp);
3450 	return (error);
3451 }
3452 
3453 /*
3454  * fchownat(int fd, char *path, int uid, int gid, int flags)
3455  *
3456  * Set ownership of file pointed to by fd/path.
3457  */
3458 int
3459 sys_fchownat(struct fchownat_args *uap)
3460 {
3461 	struct nlookupdata nd;
3462 	struct file *fp;
3463 	int error;
3464 	int flags;
3465 
3466 	if (uap->flags & ~AT_SYMLINK_NOFOLLOW)
3467 		return (EINVAL);
3468 	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
3469 
3470 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path,
3471 				UIO_USERSPACE, flags);
3472 	if (error == 0)
3473 		error = kern_chown(&nd, uap->uid, uap->gid);
3474 	nlookup_done_at(&nd, fp);
3475 	return (error);
3476 }
3477 
3478 
3479 static int
3480 getutimes(struct timeval *tvp, struct timespec *tsp)
3481 {
3482 	struct timeval tv[2];
3483 	int error;
3484 
3485 	if (tvp == NULL) {
3486 		microtime(&tv[0]);
3487 		TIMEVAL_TO_TIMESPEC(&tv[0], &tsp[0]);
3488 		tsp[1] = tsp[0];
3489 	} else {
3490 		if ((error = itimerfix(tvp)) != 0)
3491 			return (error);
3492 		TIMEVAL_TO_TIMESPEC(&tvp[0], &tsp[0]);
3493 		TIMEVAL_TO_TIMESPEC(&tvp[1], &tsp[1]);
3494 	}
3495 	return 0;
3496 }
3497 
3498 static int
3499 getutimens(const struct timespec *ts, struct timespec *newts, int *nullflag)
3500 {
3501 	struct timespec tsnow;
3502 	int error;
3503 
3504 	*nullflag = 0;
3505 	nanotime(&tsnow);
3506 	if (ts == NULL) {
3507 		newts[0] = tsnow;
3508 		newts[1] = tsnow;
3509 		*nullflag = 1;
3510 		return (0);
3511 	}
3512 
3513 	newts[0] = ts[0];
3514 	newts[1] = ts[1];
3515 	if (newts[0].tv_nsec == UTIME_OMIT && newts[1].tv_nsec == UTIME_OMIT)
3516 		return (0);
3517 	if (newts[0].tv_nsec == UTIME_NOW && newts[1].tv_nsec == UTIME_NOW)
3518 		*nullflag = 1;
3519 
3520 	if (newts[0].tv_nsec == UTIME_OMIT)
3521 		newts[0].tv_sec = VNOVAL;
3522 	else if (newts[0].tv_nsec == UTIME_NOW)
3523 		newts[0] = tsnow;
3524 	else if ((error = itimespecfix(&newts[0])) != 0)
3525 		return (error);
3526 
3527 	if (newts[1].tv_nsec == UTIME_OMIT)
3528 		newts[1].tv_sec = VNOVAL;
3529 	else if (newts[1].tv_nsec == UTIME_NOW)
3530 		newts[1] = tsnow;
3531 	else if ((error = itimespecfix(&newts[1])) != 0)
3532 		return (error);
3533 
3534 	return (0);
3535 }
3536 
3537 static int
3538 setutimes(struct vnode *vp, struct vattr *vattr,
3539 	  const struct timespec *ts, int nullflag)
3540 {
3541 	struct thread *td = curthread;
3542 	int error;
3543 
3544 	VATTR_NULL(vattr);
3545 	vattr->va_atime = ts[0];
3546 	vattr->va_mtime = ts[1];
3547 	if (nullflag)
3548 		vattr->va_vaflags |= VA_UTIMES_NULL;
3549 	error = VOP_SETATTR(vp, vattr, td->td_ucred);
3550 
3551 	return error;
3552 }
3553 
3554 int
3555 kern_utimes(struct nlookupdata *nd, struct timeval *tptr)
3556 {
3557 	struct timespec ts[2];
3558 	int error;
3559 
3560 	if (tptr) {
3561 		if ((error = getutimes(tptr, ts)) != 0)
3562 			return (error);
3563 	}
3564 	error = kern_utimensat(nd, tptr ? ts : NULL, 0);
3565 	return (error);
3566 }
3567 
3568 /*
3569  * utimes_args(char *path, struct timeval *tptr)
3570  *
3571  * Set the access and modification times of a file.
3572  */
3573 int
3574 sys_utimes(struct utimes_args *uap)
3575 {
3576 	struct timeval tv[2];
3577 	struct nlookupdata nd;
3578 	int error;
3579 
3580 	if (uap->tptr) {
3581  		error = copyin(uap->tptr, tv, sizeof(tv));
3582 		if (error)
3583 			return (error);
3584 	}
3585 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3586 	if (error == 0)
3587 		error = kern_utimes(&nd, uap->tptr ? tv : NULL);
3588 	nlookup_done(&nd);
3589 	return (error);
3590 }
3591 
3592 /*
3593  * lutimes_args(char *path, struct timeval *tptr)
3594  *
3595  * Set the access and modification times of a file.
3596  */
3597 int
3598 sys_lutimes(struct lutimes_args *uap)
3599 {
3600 	struct timeval tv[2];
3601 	struct nlookupdata nd;
3602 	int error;
3603 
3604 	if (uap->tptr) {
3605 		error = copyin(uap->tptr, tv, sizeof(tv));
3606 		if (error)
3607 			return (error);
3608 	}
3609 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3610 	if (error == 0)
3611 		error = kern_utimes(&nd, uap->tptr ? tv : NULL);
3612 	nlookup_done(&nd);
3613 	return (error);
3614 }
3615 
3616 /*
3617  * Set utimes on a file descriptor.  The creds used to open the
3618  * file are used to determine whether the operation is allowed
3619  * or not.
3620  */
3621 int
3622 kern_futimens(int fd, struct timespec *ts)
3623 {
3624 	struct thread *td = curthread;
3625 	struct proc *p = td->td_proc;
3626 	struct timespec newts[2];
3627 	struct file *fp;
3628 	struct vnode *vp;
3629 	struct vattr vattr;
3630 	int nullflag;
3631 	int error;
3632 
3633 	error = getutimens(ts, newts, &nullflag);
3634 	if (error)
3635 		return (error);
3636 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
3637 		return (error);
3638 	if (fp->f_nchandle.ncp)
3639 		error = ncp_writechk(&fp->f_nchandle);
3640 	if (error == 0) {
3641 		vp = fp->f_data;
3642 		error = vget(vp, LK_EXCLUSIVE);
3643 		if (error == 0) {
3644 			error = VOP_GETATTR(vp, &vattr);
3645 			if (error == 0) {
3646 				error = naccess_va(&vattr, NLC_OWN | NLC_WRITE,
3647 						   fp->f_cred);
3648 			}
3649 			if (error == 0) {
3650 				error = setutimes(vp, &vattr, newts, nullflag);
3651 			}
3652 			vput(vp);
3653 		}
3654 	}
3655 	fdrop(fp);
3656 	return (error);
3657 }
3658 
3659 /*
3660  * futimens_args(int fd, struct timespec *ts)
3661  *
3662  * Set the access and modification times of a file.
3663  */
3664 int
3665 sys_futimens(struct futimens_args *uap)
3666 {
3667 	struct timespec ts[2];
3668 	int error;
3669 
3670 	if (uap->ts) {
3671 		error = copyin(uap->ts, ts, sizeof(ts));
3672 		if (error)
3673 			return (error);
3674 	}
3675 	error = kern_futimens(uap->fd, uap->ts ? ts : NULL);
3676 	return (error);
3677 }
3678 
3679 int
3680 kern_futimes(int fd, struct timeval *tptr)
3681 {
3682 	struct timespec ts[2];
3683 	int error;
3684 
3685 	if (tptr) {
3686 		if ((error = getutimes(tptr, ts)) != 0)
3687 			return (error);
3688 	}
3689 	error = kern_futimens(fd, tptr ? ts : NULL);
3690 	return (error);
3691 }
3692 
3693 /*
3694  * futimes_args(int fd, struct timeval *tptr)
3695  *
3696  * Set the access and modification times of a file.
3697  */
3698 int
3699 sys_futimes(struct futimes_args *uap)
3700 {
3701 	struct timeval tv[2];
3702 	int error;
3703 
3704 	if (uap->tptr) {
3705 		error = copyin(uap->tptr, tv, sizeof(tv));
3706 		if (error)
3707 			return (error);
3708 	}
3709 	error = kern_futimes(uap->fd, uap->tptr ? tv : NULL);
3710 	return (error);
3711 }
3712 
3713 int
3714 kern_utimensat(struct nlookupdata *nd, const struct timespec *ts, int flags)
3715 {
3716 	struct timespec newts[2];
3717 	struct vnode *vp;
3718 	struct vattr vattr;
3719 	int nullflag;
3720 	int error;
3721 
3722 	if (flags & ~AT_SYMLINK_NOFOLLOW)
3723 		return (EINVAL);
3724 
3725 	error = getutimens(ts, newts, &nullflag);
3726 	if (error)
3727 		return (error);
3728 
3729 	nd->nl_flags |= NLC_OWN | NLC_WRITE;
3730 	if ((error = nlookup(nd)) != 0)
3731 		return (error);
3732 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3733 		return (error);
3734 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
3735 		return (error);
3736 	if ((error = vn_writechk(vp, &nd->nl_nch)) == 0) {
3737 		error = vget(vp, LK_EXCLUSIVE);
3738 		if (error == 0) {
3739 			error = setutimes(vp, &vattr, newts, nullflag);
3740 			vput(vp);
3741 		}
3742 	}
3743 	vrele(vp);
3744 	return (error);
3745 }
3746 
3747 /*
3748  * utimensat_args(int fd, const char *path, const struct timespec *ts, int flags);
3749  *
3750  * Set file access and modification times of a file.
3751  */
3752 int
3753 sys_utimensat(struct utimensat_args *uap)
3754 {
3755 	struct timespec ts[2];
3756 	struct nlookupdata nd;
3757 	struct file *fp;
3758 	int error;
3759 	int flags;
3760 
3761 	if (uap->ts) {
3762 		error = copyin(uap->ts, ts, sizeof(ts));
3763 		if (error)
3764 			return (error);
3765 	}
3766 
3767 	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
3768 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path,
3769 	                        UIO_USERSPACE, flags);
3770 	if (error == 0)
3771 		error = kern_utimensat(&nd, uap->ts ? ts : NULL, uap->flags);
3772 	nlookup_done_at(&nd, fp);
3773 	return (error);
3774 }
3775 
3776 int
3777 kern_truncate(struct nlookupdata *nd, off_t length)
3778 {
3779 	struct vnode *vp;
3780 	struct vattr vattr;
3781 	int error;
3782 	uid_t uid = 0;
3783 	gid_t gid = 0;
3784 	uint64_t old_size = 0;
3785 
3786 	if (length < 0)
3787 		return(EINVAL);
3788 	nd->nl_flags |= NLC_WRITE | NLC_TRUNCATE;
3789 	if ((error = nlookup(nd)) != 0)
3790 		return (error);
3791 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3792 		return (error);
3793 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
3794 		return (error);
3795 	error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_FAILRECLAIM);
3796 	if (error) {
3797 		vrele(vp);
3798 		return (error);
3799 	}
3800 	if (vp->v_type == VDIR) {
3801 		error = EISDIR;
3802 		goto done;
3803 	}
3804 	if (vfs_quota_enabled) {
3805 		error = VOP_GETATTR(vp, &vattr);
3806 		KASSERT(error == 0, ("kern_truncate(): VOP_GETATTR didn't return 0"));
3807 		uid = vattr.va_uid;
3808 		gid = vattr.va_gid;
3809 		old_size = vattr.va_size;
3810 	}
3811 
3812 	if ((error = vn_writechk(vp, &nd->nl_nch)) == 0) {
3813 		VATTR_NULL(&vattr);
3814 		vattr.va_size = length;
3815 		error = VOP_SETATTR(vp, &vattr, nd->nl_cred);
3816 		VFS_ACCOUNT(nd->nl_nch.mount, uid, gid, length - old_size);
3817 	}
3818 done:
3819 	vput(vp);
3820 	return (error);
3821 }
3822 
3823 /*
3824  * truncate(char *path, int pad, off_t length)
3825  *
3826  * Truncate a file given its path name.
3827  */
3828 int
3829 sys_truncate(struct truncate_args *uap)
3830 {
3831 	struct nlookupdata nd;
3832 	int error;
3833 
3834 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3835 	if (error == 0)
3836 		error = kern_truncate(&nd, uap->length);
3837 	nlookup_done(&nd);
3838 	return error;
3839 }
3840 
3841 int
3842 kern_ftruncate(int fd, off_t length)
3843 {
3844 	struct thread *td = curthread;
3845 	struct proc *p = td->td_proc;
3846 	struct vattr vattr;
3847 	struct vnode *vp;
3848 	struct file *fp;
3849 	int error;
3850 	uid_t uid = 0;
3851 	gid_t gid = 0;
3852 	uint64_t old_size = 0;
3853 	struct mount *mp;
3854 
3855 	if (length < 0)
3856 		return(EINVAL);
3857 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
3858 		return (error);
3859 	if (fp->f_nchandle.ncp) {
3860 		error = ncp_writechk(&fp->f_nchandle);
3861 		if (error)
3862 			goto done;
3863 	}
3864 	if ((fp->f_flag & FWRITE) == 0) {
3865 		error = EINVAL;
3866 		goto done;
3867 	}
3868 	if (fp->f_flag & FAPPENDONLY) {	/* inode was set s/uapnd */
3869 		error = EINVAL;
3870 		goto done;
3871 	}
3872 	vp = (struct vnode *)fp->f_data;
3873 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3874 	if (vp->v_type == VDIR) {
3875 		error = EISDIR;
3876 		vn_unlock(vp);
3877 		goto done;
3878 	}
3879 
3880 	if (vfs_quota_enabled) {
3881 		error = VOP_GETATTR(vp, &vattr);
3882 		KASSERT(error == 0, ("kern_ftruncate(): VOP_GETATTR didn't return 0"));
3883 		uid = vattr.va_uid;
3884 		gid = vattr.va_gid;
3885 		old_size = vattr.va_size;
3886 	}
3887 
3888 	if ((error = vn_writechk(vp, NULL)) == 0) {
3889 		VATTR_NULL(&vattr);
3890 		vattr.va_size = length;
3891 		error = VOP_SETATTR(vp, &vattr, fp->f_cred);
3892 		mp = vq_vptomp(vp);
3893 		VFS_ACCOUNT(mp, uid, gid, length - old_size);
3894 	}
3895 	vn_unlock(vp);
3896 done:
3897 	fdrop(fp);
3898 	return (error);
3899 }
3900 
3901 /*
3902  * ftruncate_args(int fd, int pad, off_t length)
3903  *
3904  * Truncate a file given a file descriptor.
3905  */
3906 int
3907 sys_ftruncate(struct ftruncate_args *uap)
3908 {
3909 	int error;
3910 
3911 	error = kern_ftruncate(uap->fd, uap->length);
3912 
3913 	return (error);
3914 }
3915 
3916 /*
3917  * fsync(int fd)
3918  *
3919  * Sync an open file.
3920  */
3921 int
3922 sys_fsync(struct fsync_args *uap)
3923 {
3924 	struct thread *td = curthread;
3925 	struct proc *p = td->td_proc;
3926 	struct vnode *vp;
3927 	struct file *fp;
3928 	vm_object_t obj;
3929 	int error;
3930 
3931 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
3932 		return (error);
3933 	vp = (struct vnode *)fp->f_data;
3934 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3935 	if ((obj = vp->v_object) != NULL) {
3936 		if (vp->v_mount == NULL ||
3937 		    (vp->v_mount->mnt_kern_flag & MNTK_NOMSYNC) == 0) {
3938 			vm_object_page_clean(obj, 0, 0, 0);
3939 		}
3940 	}
3941 	error = VOP_FSYNC(vp, MNT_WAIT, VOP_FSYNC_SYSCALL);
3942 	if (error == 0 && vp->v_mount)
3943 		error = buf_fsync(vp);
3944 	vn_unlock(vp);
3945 	fdrop(fp);
3946 
3947 	return (error);
3948 }
3949 
3950 int
3951 kern_rename(struct nlookupdata *fromnd, struct nlookupdata *tond)
3952 {
3953 	struct nchandle fnchd;
3954 	struct nchandle tnchd;
3955 	struct namecache *ncp;
3956 	struct vnode *fdvp;
3957 	struct vnode *tdvp;
3958 	struct mount *mp;
3959 	int error;
3960 	u_int fncp_gen;
3961 	u_int tncp_gen;
3962 
3963 	bwillinode(1);
3964 	fromnd->nl_flags |= NLC_REFDVP | NLC_RENAME_SRC;
3965 	if ((error = nlookup(fromnd)) != 0)
3966 		return (error);
3967 	if ((fnchd.ncp = fromnd->nl_nch.ncp->nc_parent) == NULL)
3968 		return (ENOENT);
3969 	fnchd.mount = fromnd->nl_nch.mount;
3970 	cache_hold(&fnchd);
3971 
3972 	/*
3973 	 * unlock the source nch so we can lookup the target nch without
3974 	 * deadlocking.  The target may or may not exist so we do not check
3975 	 * for a target vp like kern_mkdir() and other creation functions do.
3976 	 *
3977 	 * The source and target directories are ref'd and rechecked after
3978 	 * everything is relocked to determine if the source or target file
3979 	 * has been renamed.
3980 	 */
3981 	KKASSERT(fromnd->nl_flags & NLC_NCPISLOCKED);
3982 	fromnd->nl_flags &= ~NLC_NCPISLOCKED;
3983 
3984 	fncp_gen = fromnd->nl_nch.ncp->nc_generation;
3985 
3986 	cache_unlock(&fromnd->nl_nch);
3987 
3988 	tond->nl_flags |= NLC_RENAME_DST | NLC_REFDVP;
3989 	if ((error = nlookup(tond)) != 0) {
3990 		cache_drop(&fnchd);
3991 		return (error);
3992 	}
3993 	tncp_gen = tond->nl_nch.ncp->nc_generation;
3994 
3995 	if ((tnchd.ncp = tond->nl_nch.ncp->nc_parent) == NULL) {
3996 		cache_drop(&fnchd);
3997 		return (ENOENT);
3998 	}
3999 	tnchd.mount = tond->nl_nch.mount;
4000 	cache_hold(&tnchd);
4001 
4002 	/*
4003 	 * If the source and target are the same there is nothing to do
4004 	 */
4005 	if (fromnd->nl_nch.ncp == tond->nl_nch.ncp) {
4006 		cache_drop(&fnchd);
4007 		cache_drop(&tnchd);
4008 		return (0);
4009 	}
4010 
4011 	/*
4012 	 * Mount points cannot be renamed or overwritten
4013 	 */
4014 	if ((fromnd->nl_nch.ncp->nc_flag | tond->nl_nch.ncp->nc_flag) &
4015 	    NCF_ISMOUNTPT
4016 	) {
4017 		cache_drop(&fnchd);
4018 		cache_drop(&tnchd);
4019 		return (EINVAL);
4020 	}
4021 
4022 	/*
4023 	 * Relock the source ncp.  cache_relock() will deal with any
4024 	 * deadlocks against the already-locked tond and will also
4025 	 * make sure both are resolved.
4026 	 *
4027 	 * NOTE AFTER RELOCKING: The source or target ncp may have become
4028 	 * invalid while they were unlocked, nc_vp and nc_mount could
4029 	 * be NULL.
4030 	 */
4031 	cache_relock(&fromnd->nl_nch, fromnd->nl_cred,
4032 		     &tond->nl_nch, tond->nl_cred);
4033 	fromnd->nl_flags |= NLC_NCPISLOCKED;
4034 
4035 	/*
4036 	 * If the namecache generation changed for either fromnd or tond,
4037 	 * we must retry.
4038 	 */
4039 	if (fromnd->nl_nch.ncp->nc_generation != fncp_gen ||
4040 	    tond->nl_nch.ncp->nc_generation != tncp_gen) {
4041 		kprintf("kern_rename: retry due to gen on: "
4042 			"\"%s\" -> \"%s\"\n",
4043 			fromnd->nl_nch.ncp->nc_name,
4044 			tond->nl_nch.ncp->nc_name);
4045 		cache_drop(&fnchd);
4046 		cache_drop(&tnchd);
4047 		return (EAGAIN);
4048 	}
4049 
4050 	/*
4051 	 * If either fromnd or tond are marked destroyed a ripout occured
4052 	 * out from under us and we must retry.
4053 	 */
4054 	if ((fromnd->nl_nch.ncp->nc_flag & (NCF_DESTROYED | NCF_UNRESOLVED)) ||
4055 	    fromnd->nl_nch.ncp->nc_vp == NULL ||
4056 	    (tond->nl_nch.ncp->nc_flag & NCF_DESTROYED)) {
4057 		kprintf("kern_rename: retry due to ripout on: "
4058 			"\"%s\" -> \"%s\"\n",
4059 			fromnd->nl_nch.ncp->nc_name,
4060 			tond->nl_nch.ncp->nc_name);
4061 		cache_drop(&fnchd);
4062 		cache_drop(&tnchd);
4063 		return (EAGAIN);
4064 	}
4065 
4066 	/*
4067 	 * Make sure the parent directories linkages are the same.
4068 	 * XXX shouldn't be needed any more w/ generation check above.
4069 	 */
4070 	if (fnchd.ncp != fromnd->nl_nch.ncp->nc_parent ||
4071 	    tnchd.ncp != tond->nl_nch.ncp->nc_parent) {
4072 		cache_drop(&fnchd);
4073 		cache_drop(&tnchd);
4074 		return (ENOENT);
4075 	}
4076 
4077 	/*
4078 	 * Both the source and target must be within the same filesystem and
4079 	 * in the same filesystem as their parent directories within the
4080 	 * namecache topology.
4081 	 *
4082 	 * NOTE: fromnd's nc_mount or nc_vp could be NULL.
4083 	 */
4084 	mp = fnchd.mount;
4085 	if (mp != tnchd.mount || mp != fromnd->nl_nch.mount ||
4086 	    mp != tond->nl_nch.mount) {
4087 		cache_drop(&fnchd);
4088 		cache_drop(&tnchd);
4089 		return (EXDEV);
4090 	}
4091 
4092 	/*
4093 	 * Make sure the mount point is writable
4094 	 */
4095 	if ((error = ncp_writechk(&tond->nl_nch)) != 0) {
4096 		cache_drop(&fnchd);
4097 		cache_drop(&tnchd);
4098 		return (error);
4099 	}
4100 
4101 	/*
4102 	 * If the target exists and either the source or target is a directory,
4103 	 * then both must be directories.
4104 	 *
4105 	 * Due to relocking of the source, fromnd->nl_nch.ncp->nc_vp might h
4106 	 * have become NULL.
4107 	 */
4108 	if (tond->nl_nch.ncp->nc_vp) {
4109 		if (fromnd->nl_nch.ncp->nc_vp == NULL) {
4110 			error = ENOENT;
4111 		} else if (fromnd->nl_nch.ncp->nc_vp->v_type == VDIR) {
4112 			if (tond->nl_nch.ncp->nc_vp->v_type != VDIR)
4113 				error = ENOTDIR;
4114 		} else if (tond->nl_nch.ncp->nc_vp->v_type == VDIR) {
4115 			error = EISDIR;
4116 		}
4117 	}
4118 
4119 	/*
4120 	 * You cannot rename a source into itself or a subdirectory of itself.
4121 	 * We check this by travsersing the target directory upwards looking
4122 	 * for a match against the source.
4123 	 *
4124 	 * XXX MPSAFE
4125 	 */
4126 	if (error == 0) {
4127 		for (ncp = tnchd.ncp; ncp; ncp = ncp->nc_parent) {
4128 			if (fromnd->nl_nch.ncp == ncp) {
4129 				error = EINVAL;
4130 				break;
4131 			}
4132 		}
4133 	}
4134 
4135 	cache_drop(&fnchd);
4136 	cache_drop(&tnchd);
4137 
4138 	/*
4139 	 * Even though the namespaces are different, they may still represent
4140 	 * hardlinks to the same file.  The filesystem might have a hard time
4141 	 * with this so we issue a NREMOVE of the source instead of a NRENAME
4142 	 * when we detect the situation.
4143 	 */
4144 	if (error == 0) {
4145 		fdvp = fromnd->nl_dvp;
4146 		tdvp = tond->nl_dvp;
4147 		if (fdvp == NULL || tdvp == NULL) {
4148 			error = EPERM;
4149 		} else if (fromnd->nl_nch.ncp->nc_vp == tond->nl_nch.ncp->nc_vp) {
4150 			error = VOP_NREMOVE(&fromnd->nl_nch, fdvp,
4151 					    fromnd->nl_cred);
4152 		} else {
4153 			error = VOP_NRENAME(&fromnd->nl_nch, &tond->nl_nch,
4154 					    fdvp, tdvp, tond->nl_cred);
4155 		}
4156 	}
4157 	return (error);
4158 }
4159 
4160 /*
4161  * rename_args(char *from, char *to)
4162  *
4163  * Rename files.  Source and destination must either both be directories,
4164  * or both not be directories.  If target is a directory, it must be empty.
4165  */
4166 int
4167 sys_rename(struct rename_args *uap)
4168 {
4169 	struct nlookupdata fromnd, tond;
4170 	int error;
4171 
4172 	do {
4173 		error = nlookup_init(&fromnd, uap->from, UIO_USERSPACE, 0);
4174 		if (error == 0) {
4175 			error = nlookup_init(&tond, uap->to, UIO_USERSPACE, 0);
4176 			if (error == 0)
4177 				error = kern_rename(&fromnd, &tond);
4178 			nlookup_done(&tond);
4179 		}
4180 		nlookup_done(&fromnd);
4181 	} while (error == EAGAIN);
4182 	return (error);
4183 }
4184 
4185 /*
4186  * renameat_args(int oldfd, char *old, int newfd, char *new)
4187  *
4188  * Rename files using paths relative to the directories associated with
4189  * oldfd and newfd.  Source and destination must either both be directories,
4190  * or both not be directories.  If target is a directory, it must be empty.
4191  */
4192 int
4193 sys_renameat(struct renameat_args *uap)
4194 {
4195 	struct nlookupdata oldnd, newnd;
4196 	struct file *oldfp, *newfp;
4197 	int error;
4198 
4199 	do {
4200 		error = nlookup_init_at(&oldnd, &oldfp,
4201 					uap->oldfd, uap->old,
4202 					UIO_USERSPACE, 0);
4203 		if (error == 0) {
4204 			error = nlookup_init_at(&newnd, &newfp,
4205 						uap->newfd, uap->new,
4206 						UIO_USERSPACE, 0);
4207 			if (error == 0)
4208 				error = kern_rename(&oldnd, &newnd);
4209 			nlookup_done_at(&newnd, newfp);
4210 		}
4211 		nlookup_done_at(&oldnd, oldfp);
4212 	} while (error == EAGAIN);
4213 	return (error);
4214 }
4215 
4216 int
4217 kern_mkdir(struct nlookupdata *nd, int mode)
4218 {
4219 	struct thread *td = curthread;
4220 	struct proc *p = td->td_proc;
4221 	struct vnode *vp;
4222 	struct vattr vattr;
4223 	int error;
4224 
4225 	bwillinode(1);
4226 	nd->nl_flags |= NLC_WILLBEDIR | NLC_CREATE | NLC_REFDVP;
4227 	if ((error = nlookup(nd)) != 0)
4228 		return (error);
4229 
4230 	if (nd->nl_nch.ncp->nc_vp)
4231 		return (EEXIST);
4232 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
4233 		return (error);
4234 	VATTR_NULL(&vattr);
4235 	vattr.va_type = VDIR;
4236 	vattr.va_mode = (mode & ACCESSPERMS) &~ p->p_fd->fd_cmask;
4237 
4238 	vp = NULL;
4239 	error = VOP_NMKDIR(&nd->nl_nch, nd->nl_dvp, &vp, td->td_ucred, &vattr);
4240 	if (error == 0)
4241 		vput(vp);
4242 	return (error);
4243 }
4244 
4245 /*
4246  * mkdir_args(char *path, int mode)
4247  *
4248  * Make a directory file.
4249  */
4250 int
4251 sys_mkdir(struct mkdir_args *uap)
4252 {
4253 	struct nlookupdata nd;
4254 	int error;
4255 
4256 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
4257 	if (error == 0)
4258 		error = kern_mkdir(&nd, uap->mode);
4259 	nlookup_done(&nd);
4260 	return (error);
4261 }
4262 
4263 /*
4264  * mkdirat_args(int fd, char *path, mode_t mode)
4265  *
4266  * Make a directory file.  The path is relative to the directory associated
4267  * with fd.
4268  */
4269 int
4270 sys_mkdirat(struct mkdirat_args *uap)
4271 {
4272 	struct nlookupdata nd;
4273 	struct file *fp;
4274 	int error;
4275 
4276 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
4277 	if (error == 0)
4278 		error = kern_mkdir(&nd, uap->mode);
4279 	nlookup_done_at(&nd, fp);
4280 	return (error);
4281 }
4282 
4283 int
4284 kern_rmdir(struct nlookupdata *nd)
4285 {
4286 	int error;
4287 
4288 	bwillinode(1);
4289 	nd->nl_flags |= NLC_DELETE | NLC_REFDVP;
4290 	if ((error = nlookup(nd)) != 0)
4291 		return (error);
4292 
4293 	/*
4294 	 * Do not allow directories representing mount points to be
4295 	 * deleted, even if empty.  Check write perms on mount point
4296 	 * in case the vnode is aliased (aka nullfs).
4297 	 */
4298 	if (nd->nl_nch.ncp->nc_flag & (NCF_ISMOUNTPT))
4299 		return (EBUSY);
4300 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
4301 		return (error);
4302 	error = VOP_NRMDIR(&nd->nl_nch, nd->nl_dvp, nd->nl_cred);
4303 	return (error);
4304 }
4305 
4306 /*
4307  * rmdir_args(char *path)
4308  *
4309  * Remove a directory file.
4310  */
4311 int
4312 sys_rmdir(struct rmdir_args *uap)
4313 {
4314 	struct nlookupdata nd;
4315 	int error;
4316 
4317 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
4318 	if (error == 0)
4319 		error = kern_rmdir(&nd);
4320 	nlookup_done(&nd);
4321 	return (error);
4322 }
4323 
4324 int
4325 kern_getdirentries(int fd, char *buf, u_int count, long *basep, int *res,
4326 		   enum uio_seg direction)
4327 {
4328 	struct thread *td = curthread;
4329 	struct proc *p = td->td_proc;
4330 	struct vnode *vp;
4331 	struct file *fp;
4332 	struct uio auio;
4333 	struct iovec aiov;
4334 	off_t loff;
4335 	int error, eofflag;
4336 
4337 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
4338 		return (error);
4339 	if ((fp->f_flag & FREAD) == 0) {
4340 		error = EBADF;
4341 		goto done;
4342 	}
4343 	vp = (struct vnode *)fp->f_data;
4344 	if (vp->v_type != VDIR) {
4345 		error = EINVAL;
4346 		goto done;
4347 	}
4348 	aiov.iov_base = buf;
4349 	aiov.iov_len = count;
4350 	auio.uio_iov = &aiov;
4351 	auio.uio_iovcnt = 1;
4352 	auio.uio_rw = UIO_READ;
4353 	auio.uio_segflg = direction;
4354 	auio.uio_td = td;
4355 	auio.uio_resid = count;
4356 	loff = auio.uio_offset = fp->f_offset;
4357 	error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, NULL, NULL);
4358 	fp->f_offset = auio.uio_offset;
4359 	if (error)
4360 		goto done;
4361 
4362 	/*
4363 	 * WARNING!  *basep may not be wide enough to accomodate the
4364 	 * seek offset.   XXX should we hack this to return the upper 32 bits
4365 	 * for offsets greater then 4G?
4366 	 */
4367 	if (basep) {
4368 		*basep = (long)loff;
4369 	}
4370 	*res = count - auio.uio_resid;
4371 done:
4372 	fdrop(fp);
4373 	return (error);
4374 }
4375 
4376 /*
4377  * getdirentries_args(int fd, char *buf, u_int conut, long *basep)
4378  *
4379  * Read a block of directory entries in a file system independent format.
4380  */
4381 int
4382 sys_getdirentries(struct getdirentries_args *uap)
4383 {
4384 	long base;
4385 	int error;
4386 
4387 	error = kern_getdirentries(uap->fd, uap->buf, uap->count, &base,
4388 				   &uap->sysmsg_result, UIO_USERSPACE);
4389 
4390 	if (error == 0 && uap->basep)
4391 		error = copyout(&base, uap->basep, sizeof(*uap->basep));
4392 	return (error);
4393 }
4394 
4395 /*
4396  * getdents_args(int fd, char *buf, size_t count)
4397  */
4398 int
4399 sys_getdents(struct getdents_args *uap)
4400 {
4401 	int error;
4402 
4403 	error = kern_getdirentries(uap->fd, uap->buf, uap->count, NULL,
4404 				   &uap->sysmsg_result, UIO_USERSPACE);
4405 
4406 	return (error);
4407 }
4408 
4409 /*
4410  * Set the mode mask for creation of filesystem nodes.
4411  *
4412  * umask(int newmask)
4413  */
4414 int
4415 sys_umask(struct umask_args *uap)
4416 {
4417 	struct thread *td = curthread;
4418 	struct proc *p = td->td_proc;
4419 	struct filedesc *fdp;
4420 
4421 	fdp = p->p_fd;
4422 	uap->sysmsg_result = fdp->fd_cmask;
4423 	fdp->fd_cmask = uap->newmask & ALLPERMS;
4424 	return (0);
4425 }
4426 
4427 /*
4428  * revoke(char *path)
4429  *
4430  * Void all references to file by ripping underlying filesystem
4431  * away from vnode.
4432  */
4433 int
4434 sys_revoke(struct revoke_args *uap)
4435 {
4436 	struct nlookupdata nd;
4437 	struct vattr vattr;
4438 	struct vnode *vp;
4439 	struct ucred *cred;
4440 	int error;
4441 
4442 	vp = NULL;
4443 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4444 	if (error == 0)
4445 		error = nlookup(&nd);
4446 	if (error == 0)
4447 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
4448 	cred = crhold(nd.nl_cred);
4449 	nlookup_done(&nd);
4450 	if (error == 0) {
4451 		if (error == 0)
4452 			error = VOP_GETATTR(vp, &vattr);
4453 		if (error == 0 && cred->cr_uid != vattr.va_uid)
4454 			error = priv_check_cred(cred, PRIV_VFS_REVOKE, 0);
4455 		if (error == 0 && (vp->v_type == VCHR || vp->v_type == VBLK)) {
4456 			if (vcount(vp) > 0)
4457 				error = vrevoke(vp, cred);
4458 		} else if (error == 0) {
4459 			error = vrevoke(vp, cred);
4460 		}
4461 		vrele(vp);
4462 	}
4463 	if (cred)
4464 		crfree(cred);
4465 	return (error);
4466 }
4467 
4468 /*
4469  * getfh_args(char *fname, fhandle_t *fhp)
4470  *
4471  * Get (NFS) file handle
4472  *
4473  * NOTE: We use the fsid of the covering mount, even if it is a nullfs
4474  * mount.  This allows nullfs mounts to be explicitly exported.
4475  *
4476  * WARNING: nullfs mounts of HAMMER PFS ROOTs are safe.
4477  *
4478  * 	    nullfs mounts of subdirectories are not safe.  That is, it will
4479  *	    work, but you do not really have protection against access to
4480  *	    the related parent directories.
4481  */
4482 int
4483 sys_getfh(struct getfh_args *uap)
4484 {
4485 	struct thread *td = curthread;
4486 	struct nlookupdata nd;
4487 	fhandle_t fh;
4488 	struct vnode *vp;
4489 	struct mount *mp;
4490 	int error;
4491 
4492 	/*
4493 	 * Must be super user
4494 	 */
4495 	if ((error = priv_check(td, PRIV_ROOT)) != 0)
4496 		return (error);
4497 
4498 	vp = NULL;
4499 	error = nlookup_init(&nd, uap->fname, UIO_USERSPACE, NLC_FOLLOW);
4500 	if (error == 0)
4501 		error = nlookup(&nd);
4502 	if (error == 0)
4503 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
4504 	mp = nd.nl_nch.mount;
4505 	nlookup_done(&nd);
4506 	if (error == 0) {
4507 		bzero(&fh, sizeof(fh));
4508 		fh.fh_fsid = mp->mnt_stat.f_fsid;
4509 		error = VFS_VPTOFH(vp, &fh.fh_fid);
4510 		vput(vp);
4511 		if (error == 0)
4512 			error = copyout(&fh, uap->fhp, sizeof(fh));
4513 	}
4514 	return (error);
4515 }
4516 
4517 /*
4518  * fhopen_args(const struct fhandle *u_fhp, int flags)
4519  *
4520  * syscall for the rpc.lockd to use to translate a NFS file handle into
4521  * an open descriptor.
4522  *
4523  * warning: do not remove the priv_check() call or this becomes one giant
4524  * security hole.
4525  */
4526 int
4527 sys_fhopen(struct fhopen_args *uap)
4528 {
4529 	struct thread *td = curthread;
4530 	struct filedesc *fdp = td->td_proc->p_fd;
4531 	struct mount *mp;
4532 	struct vnode *vp;
4533 	struct fhandle fhp;
4534 	struct vattr vat;
4535 	struct vattr *vap = &vat;
4536 	struct flock lf;
4537 	int fmode, mode, error = 0, type;
4538 	struct file *nfp;
4539 	struct file *fp;
4540 	int indx;
4541 
4542 	/*
4543 	 * Must be super user
4544 	 */
4545 	error = priv_check(td, PRIV_ROOT);
4546 	if (error)
4547 		return (error);
4548 
4549 	fmode = FFLAGS(uap->flags);
4550 
4551 	/*
4552 	 * Why not allow a non-read/write open for our lockd?
4553 	 */
4554 	if (((fmode & (FREAD | FWRITE)) == 0) || (fmode & O_CREAT))
4555 		return (EINVAL);
4556 	error = copyin(uap->u_fhp, &fhp, sizeof(fhp));
4557 	if (error)
4558 		return(error);
4559 
4560 	/*
4561 	 * Find the mount point
4562 	 */
4563 	mp = vfs_getvfs(&fhp.fh_fsid);
4564 	if (mp == NULL) {
4565 		error = ESTALE;
4566 		goto  done;
4567 	}
4568 	/* now give me my vnode, it gets returned to me locked */
4569 	error = VFS_FHTOVP(mp, NULL, &fhp.fh_fid, &vp);
4570 	if (error)
4571 		goto done;
4572  	/*
4573 	 * from now on we have to make sure not
4574 	 * to forget about the vnode
4575 	 * any error that causes an abort must vput(vp)
4576 	 * just set error = err and 'goto bad;'.
4577 	 */
4578 
4579 	/*
4580 	 * from vn_open
4581 	 */
4582 	if (vp->v_type == VLNK) {
4583 		error = EMLINK;
4584 		goto bad;
4585 	}
4586 	if (vp->v_type == VSOCK) {
4587 		error = EOPNOTSUPP;
4588 		goto bad;
4589 	}
4590 	mode = 0;
4591 	if (fmode & (FWRITE | O_TRUNC)) {
4592 		if (vp->v_type == VDIR) {
4593 			error = EISDIR;
4594 			goto bad;
4595 		}
4596 		error = vn_writechk(vp, NULL);
4597 		if (error)
4598 			goto bad;
4599 		mode |= VWRITE;
4600 	}
4601 	if (fmode & FREAD)
4602 		mode |= VREAD;
4603 	if (mode) {
4604 		error = VOP_ACCESS(vp, mode, td->td_ucred);
4605 		if (error)
4606 			goto bad;
4607 	}
4608 	if (fmode & O_TRUNC) {
4609 		vn_unlock(vp);				/* XXX */
4610 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);	/* XXX */
4611 		VATTR_NULL(vap);
4612 		vap->va_size = 0;
4613 		error = VOP_SETATTR(vp, vap, td->td_ucred);
4614 		if (error)
4615 			goto bad;
4616 	}
4617 
4618 	/*
4619 	 * VOP_OPEN needs the file pointer so it can potentially override
4620 	 * it.
4621 	 *
4622 	 * WARNING! no f_nchandle will be associated when fhopen()ing a
4623 	 * directory.  XXX
4624 	 */
4625 	if ((error = falloc(td->td_lwp, &nfp, &indx)) != 0)
4626 		goto bad;
4627 	fp = nfp;
4628 
4629 	error = VOP_OPEN(vp, fmode, td->td_ucred, fp);
4630 	if (error) {
4631 		/*
4632 		 * setting f_ops this way prevents VOP_CLOSE from being
4633 		 * called or fdrop() releasing the vp from v_data.   Since
4634 		 * the VOP_OPEN failed we don't want to VOP_CLOSE.
4635 		 */
4636 		fp->f_ops = &badfileops;
4637 		fp->f_data = NULL;
4638 		goto bad_drop;
4639 	}
4640 
4641 	/*
4642 	 * The fp is given its own reference, we still have our ref and lock.
4643 	 *
4644 	 * Assert that all regular files must be created with a VM object.
4645 	 */
4646 	if (vp->v_type == VREG && vp->v_object == NULL) {
4647 		kprintf("fhopen: regular file did not have VM object: %p\n", vp);
4648 		goto bad_drop;
4649 	}
4650 
4651 	/*
4652 	 * The open was successful.  Handle any locking requirements.
4653 	 */
4654 	if (fmode & (O_EXLOCK | O_SHLOCK)) {
4655 		lf.l_whence = SEEK_SET;
4656 		lf.l_start = 0;
4657 		lf.l_len = 0;
4658 		if (fmode & O_EXLOCK)
4659 			lf.l_type = F_WRLCK;
4660 		else
4661 			lf.l_type = F_RDLCK;
4662 		if (fmode & FNONBLOCK)
4663 			type = 0;
4664 		else
4665 			type = F_WAIT;
4666 		vn_unlock(vp);
4667 		if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0) {
4668 			/*
4669 			 * release our private reference.
4670 			 */
4671 			fsetfd(fdp, NULL, indx);
4672 			fdrop(fp);
4673 			vrele(vp);
4674 			goto done;
4675 		}
4676 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
4677 		atomic_set_int(&fp->f_flag, FHASLOCK);	/* race ok */
4678 	}
4679 
4680 	/*
4681 	 * Clean up.  Associate the file pointer with the previously
4682 	 * reserved descriptor and return it.
4683 	 */
4684 	vput(vp);
4685 	if (uap->flags & O_CLOEXEC)
4686 		fdp->fd_files[indx].fileflags |= UF_EXCLOSE;
4687 	fsetfd(fdp, fp, indx);
4688 	fdrop(fp);
4689 	uap->sysmsg_result = indx;
4690 	return (error);
4691 
4692 bad_drop:
4693 	fsetfd(fdp, NULL, indx);
4694 	fdrop(fp);
4695 bad:
4696 	vput(vp);
4697 done:
4698 	return (error);
4699 }
4700 
4701 /*
4702  * fhstat_args(struct fhandle *u_fhp, struct stat *sb)
4703  */
4704 int
4705 sys_fhstat(struct fhstat_args *uap)
4706 {
4707 	struct thread *td = curthread;
4708 	struct stat sb;
4709 	fhandle_t fh;
4710 	struct mount *mp;
4711 	struct vnode *vp;
4712 	int error;
4713 
4714 	/*
4715 	 * Must be super user
4716 	 */
4717 	error = priv_check(td, PRIV_ROOT);
4718 	if (error)
4719 		return (error);
4720 
4721 	error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t));
4722 	if (error)
4723 		return (error);
4724 
4725 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL)
4726 		error = ESTALE;
4727 	if (error == 0) {
4728 		if ((error = VFS_FHTOVP(mp, NULL, &fh.fh_fid, &vp)) == 0) {
4729 			error = vn_stat(vp, &sb, td->td_ucred);
4730 			vput(vp);
4731 		}
4732 	}
4733 	if (error == 0)
4734 		error = copyout(&sb, uap->sb, sizeof(sb));
4735 	return (error);
4736 }
4737 
4738 /*
4739  * fhstatfs_args(struct fhandle *u_fhp, struct statfs *buf)
4740  */
4741 int
4742 sys_fhstatfs(struct fhstatfs_args *uap)
4743 {
4744 	struct thread *td = curthread;
4745 	struct proc *p = td->td_proc;
4746 	struct statfs *sp;
4747 	struct mount *mp;
4748 	struct vnode *vp;
4749 	struct statfs sb;
4750 	char *fullpath, *freepath;
4751 	fhandle_t fh;
4752 	int error;
4753 
4754 	/*
4755 	 * Must be super user
4756 	 */
4757 	if ((error = priv_check(td, PRIV_ROOT)))
4758 		return (error);
4759 
4760 	if ((error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t))) != 0)
4761 		return (error);
4762 
4763 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL) {
4764 		error = ESTALE;
4765 		goto done;
4766 	}
4767 	if (p != NULL && !chroot_visible_mnt(mp, p)) {
4768 		error = ESTALE;
4769 		goto done;
4770 	}
4771 
4772 	if ((error = VFS_FHTOVP(mp, NULL, &fh.fh_fid, &vp)) != 0)
4773 		goto done;
4774 	mp = vp->v_mount;
4775 	sp = &mp->mnt_stat;
4776 	vput(vp);
4777 	if ((error = VFS_STATFS(mp, sp, td->td_ucred)) != 0)
4778 		goto done;
4779 
4780 	error = mount_path(p, mp, &fullpath, &freepath);
4781 	if (error)
4782 		goto done;
4783 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
4784 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
4785 	kfree(freepath, M_TEMP);
4786 
4787 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
4788 	if (priv_check(td, PRIV_ROOT)) {
4789 		bcopy(sp, &sb, sizeof(sb));
4790 		sb.f_fsid.val[0] = sb.f_fsid.val[1] = 0;
4791 		sp = &sb;
4792 	}
4793 	error = copyout(sp, uap->buf, sizeof(*sp));
4794 done:
4795 	return (error);
4796 }
4797 
4798 /*
4799  * fhstatvfs_args(struct fhandle *u_fhp, struct statvfs *buf)
4800  */
4801 int
4802 sys_fhstatvfs(struct fhstatvfs_args *uap)
4803 {
4804 	struct thread *td = curthread;
4805 	struct proc *p = td->td_proc;
4806 	struct statvfs *sp;
4807 	struct mount *mp;
4808 	struct vnode *vp;
4809 	fhandle_t fh;
4810 	int error;
4811 
4812 	/*
4813 	 * Must be super user
4814 	 */
4815 	if ((error = priv_check(td, PRIV_ROOT)))
4816 		return (error);
4817 
4818 	if ((error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t))) != 0)
4819 		return (error);
4820 
4821 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL) {
4822 		error = ESTALE;
4823 		goto done;
4824 	}
4825 	if (p != NULL && !chroot_visible_mnt(mp, p)) {
4826 		error = ESTALE;
4827 		goto done;
4828 	}
4829 
4830 	if ((error = VFS_FHTOVP(mp, NULL, &fh.fh_fid, &vp)))
4831 		goto done;
4832 	mp = vp->v_mount;
4833 	sp = &mp->mnt_vstat;
4834 	vput(vp);
4835 	if ((error = VFS_STATVFS(mp, sp, td->td_ucred)) != 0)
4836 		goto done;
4837 
4838 	sp->f_flag = 0;
4839 	if (mp->mnt_flag & MNT_RDONLY)
4840 		sp->f_flag |= ST_RDONLY;
4841 	if (mp->mnt_flag & MNT_NOSUID)
4842 		sp->f_flag |= ST_NOSUID;
4843 	error = copyout(sp, uap->buf, sizeof(*sp));
4844 done:
4845 	return (error);
4846 }
4847 
4848 
4849 /*
4850  * Syscall to push extended attribute configuration information into the
4851  * VFS.  Accepts a path, which it converts to a mountpoint, as well as
4852  * a command (int cmd), and attribute name and misc data.  For now, the
4853  * attribute name is left in userspace for consumption by the VFS_op.
4854  * It will probably be changed to be copied into sysspace by the
4855  * syscall in the future, once issues with various consumers of the
4856  * attribute code have raised their hands.
4857  *
4858  * Currently this is used only by UFS Extended Attributes.
4859  */
4860 int
4861 sys_extattrctl(struct extattrctl_args *uap)
4862 {
4863 	struct nlookupdata nd;
4864 	struct vnode *vp;
4865 	char attrname[EXTATTR_MAXNAMELEN];
4866 	int error;
4867 	size_t size;
4868 
4869 	attrname[0] = 0;
4870 	vp = NULL;
4871 	error = 0;
4872 
4873 	if (error == 0 && uap->filename) {
4874 		error = nlookup_init(&nd, uap->filename, UIO_USERSPACE,
4875 				     NLC_FOLLOW);
4876 		if (error == 0)
4877 			error = nlookup(&nd);
4878 		if (error == 0)
4879 			error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
4880 		nlookup_done(&nd);
4881 	}
4882 
4883 	if (error == 0 && uap->attrname) {
4884 		error = copyinstr(uap->attrname, attrname, EXTATTR_MAXNAMELEN,
4885 				  &size);
4886 	}
4887 
4888 	if (error == 0) {
4889 		error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4890 		if (error == 0)
4891 			error = nlookup(&nd);
4892 		if (error == 0)
4893 			error = ncp_writechk(&nd.nl_nch);
4894 		if (error == 0) {
4895 			error = VFS_EXTATTRCTL(nd.nl_nch.mount, uap->cmd, vp,
4896 					       uap->attrnamespace,
4897 					       uap->attrname, nd.nl_cred);
4898 		}
4899 		nlookup_done(&nd);
4900 	}
4901 
4902 	return (error);
4903 }
4904 
4905 /*
4906  * Syscall to get a named extended attribute on a file or directory.
4907  */
4908 int
4909 sys_extattr_set_file(struct extattr_set_file_args *uap)
4910 {
4911 	char attrname[EXTATTR_MAXNAMELEN];
4912 	struct nlookupdata nd;
4913 	struct vnode *vp;
4914 	struct uio auio;
4915 	struct iovec aiov;
4916 	int error;
4917 
4918 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
4919 	if (error)
4920 		return (error);
4921 
4922 	vp = NULL;
4923 
4924 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4925 	if (error == 0)
4926 		error = nlookup(&nd);
4927 	if (error == 0)
4928 		error = ncp_writechk(&nd.nl_nch);
4929 	if (error == 0)
4930 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
4931 	if (error) {
4932 		nlookup_done(&nd);
4933 		return (error);
4934 	}
4935 
4936 	bzero(&auio, sizeof(auio));
4937 	aiov.iov_base = uap->data;
4938 	aiov.iov_len = uap->nbytes;
4939 	auio.uio_iov = &aiov;
4940 	auio.uio_iovcnt = 1;
4941 	auio.uio_offset = 0;
4942 	auio.uio_resid = uap->nbytes;
4943 	auio.uio_rw = UIO_WRITE;
4944 	auio.uio_td = curthread;
4945 
4946 	error = VOP_SETEXTATTR(vp, uap->attrnamespace, attrname,
4947 			       &auio, nd.nl_cred);
4948 
4949 	vput(vp);
4950 	nlookup_done(&nd);
4951 	return (error);
4952 }
4953 
4954 /*
4955  * Syscall to get a named extended attribute on a file or directory.
4956  */
4957 int
4958 sys_extattr_get_file(struct extattr_get_file_args *uap)
4959 {
4960 	char attrname[EXTATTR_MAXNAMELEN];
4961 	struct nlookupdata nd;
4962 	struct uio auio;
4963 	struct iovec aiov;
4964 	struct vnode *vp;
4965 	int error;
4966 
4967 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
4968 	if (error)
4969 		return (error);
4970 
4971 	vp = NULL;
4972 
4973 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4974 	if (error == 0)
4975 		error = nlookup(&nd);
4976 	if (error == 0)
4977 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_SHARED, &vp);
4978 	if (error) {
4979 		nlookup_done(&nd);
4980 		return (error);
4981 	}
4982 
4983 	bzero(&auio, sizeof(auio));
4984 	aiov.iov_base = uap->data;
4985 	aiov.iov_len = uap->nbytes;
4986 	auio.uio_iov = &aiov;
4987 	auio.uio_iovcnt = 1;
4988 	auio.uio_offset = 0;
4989 	auio.uio_resid = uap->nbytes;
4990 	auio.uio_rw = UIO_READ;
4991 	auio.uio_td = curthread;
4992 
4993 	error = VOP_GETEXTATTR(vp, uap->attrnamespace, attrname,
4994 				&auio, nd.nl_cred);
4995 	uap->sysmsg_result = uap->nbytes - auio.uio_resid;
4996 
4997 	vput(vp);
4998 	nlookup_done(&nd);
4999 	return(error);
5000 }
5001 
5002 /*
5003  * Syscall to delete a named extended attribute from a file or directory.
5004  * Accepts attribute name.  The real work happens in VOP_SETEXTATTR().
5005  */
5006 int
5007 sys_extattr_delete_file(struct extattr_delete_file_args *uap)
5008 {
5009 	char attrname[EXTATTR_MAXNAMELEN];
5010 	struct nlookupdata nd;
5011 	struct vnode *vp;
5012 	int error;
5013 
5014 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
5015 	if (error)
5016 		return(error);
5017 
5018 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
5019 	if (error == 0)
5020 		error = nlookup(&nd);
5021 	if (error == 0)
5022 		error = ncp_writechk(&nd.nl_nch);
5023 	if (error == 0) {
5024 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
5025 		if (error == 0) {
5026 			error = VOP_SETEXTATTR(vp, uap->attrnamespace,
5027 					       attrname, NULL, nd.nl_cred);
5028 			vput(vp);
5029 		}
5030 	}
5031 	nlookup_done(&nd);
5032 	return(error);
5033 }
5034 
5035 /*
5036  * Determine if the mount is visible to the process.
5037  */
5038 static int
5039 chroot_visible_mnt(struct mount *mp, struct proc *p)
5040 {
5041 	struct nchandle nch;
5042 
5043 	/*
5044 	 * Traverse from the mount point upwards.  If we hit the process
5045 	 * root then the mount point is visible to the process.
5046 	 */
5047 	nch = mp->mnt_ncmountpt;
5048 	while (nch.ncp) {
5049 		if (nch.mount == p->p_fd->fd_nrdir.mount &&
5050 		    nch.ncp == p->p_fd->fd_nrdir.ncp) {
5051 			return(1);
5052 		}
5053 		if (nch.ncp == nch.mount->mnt_ncmountpt.ncp) {
5054 			nch = nch.mount->mnt_ncmounton;
5055 		} else {
5056 			nch.ncp = nch.ncp->nc_parent;
5057 		}
5058 	}
5059 
5060 	/*
5061 	 * If the mount point is not visible to the process, but the
5062 	 * process root is in a subdirectory of the mount, return
5063 	 * TRUE anyway.
5064 	 */
5065 	if (p->p_fd->fd_nrdir.mount == mp)
5066 		return(1);
5067 
5068 	return(0);
5069 }
5070 
5071