xref: /dragonfly/sys/kern/vfs_syscalls.c (revision a42bad2d)
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 (thread_t td, 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, 0);
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  * When halting we shortcut certain mount types such as devfs by not actually
689  * issuing the VFS_SYNC() or VFS_UNMOUNT().  They are still disconnected
690  * from the mountlist so higher-level filesytems can unmount cleanly.
691  *
692  * The mount types that allow QUICKHALT are: devfs, tmpfs, procfs.
693  */
694 int
695 dounmount(struct mount *mp, int flags, int halting)
696 {
697 	struct namecache *ncp;
698 	struct nchandle nch;
699 	struct vnode *vp;
700 	int error;
701 	int async_flag;
702 	int lflags;
703 	int freeok = 1;
704 	int retry;
705 	int quickhalt;
706 
707 	lwkt_gettoken(&mp->mnt_token);
708 
709 	/*
710 	 * When halting, certain mount points can essentially just
711 	 * be unhooked and otherwise ignored.
712 	 */
713 	if (halting && (mp->mnt_kern_flag & MNTK_QUICKHALT)) {
714 		quickhalt = 1;
715 		freeok = 0;
716 	} else {
717 		quickhalt = 0;
718 	}
719 
720 
721 	/*
722 	 * Exclusive access for unmounting purposes.
723 	 */
724 	if ((error = mountlist_interlock(dounmount_interlock, mp)) != 0)
725 		goto out;
726 
727 	/*
728 	 * We now 'own' the last mp->mnt_refs
729 	 *
730 	 * Allow filesystems to detect that a forced unmount is in progress.
731 	 */
732 	if (flags & MNT_FORCE)
733 		mp->mnt_kern_flag |= MNTK_UNMOUNTF;
734 	lflags = LK_EXCLUSIVE | ((flags & MNT_FORCE) ? 0 : LK_TIMELOCK);
735 	error = lockmgr(&mp->mnt_lock, lflags);
736 	if (error) {
737 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
738 		if (mp->mnt_kern_flag & MNTK_MWAIT) {
739 			mp->mnt_kern_flag &= ~MNTK_MWAIT;
740 			wakeup(mp);
741 		}
742 		goto out;
743 	}
744 
745 	if (mp->mnt_flag & MNT_EXPUBLIC)
746 		vfs_setpublicfs(NULL, NULL, NULL);
747 
748 	vfs_msync(mp, MNT_WAIT);
749 	async_flag = mp->mnt_flag & MNT_ASYNC;
750 	mp->mnt_flag &=~ MNT_ASYNC;
751 
752 	/*
753 	 * If this filesystem isn't aliasing other filesystems,
754 	 * try to invalidate any remaining namecache entries and
755 	 * check the count afterwords.
756 	 *
757 	 * We own the last mnt_refs by owning mnt_ncmountpt.
758 	 */
759 	if ((mp->mnt_kern_flag & MNTK_NCALIASED) == 0) {
760 		cache_lock(&mp->mnt_ncmountpt);
761 		cache_inval(&mp->mnt_ncmountpt, CINV_DESTROY|CINV_CHILDREN);
762 		cache_unlock(&mp->mnt_ncmountpt);
763 
764 		cache_clearmntcache();
765 		if ((ncp = mp->mnt_ncmountpt.ncp) != NULL &&
766 		    (ncp->nc_refs != 1 || TAILQ_FIRST(&ncp->nc_list))) {
767 			allproc_scan(&unmount_allproc_cb, mp, 0);
768 		}
769 
770 		cache_clearmntcache();
771 		if ((ncp = mp->mnt_ncmountpt.ncp) != NULL &&
772 		    (ncp->nc_refs != 1 || TAILQ_FIRST(&ncp->nc_list))) {
773 
774 			if ((flags & MNT_FORCE) == 0) {
775 				error = EBUSY;
776 				mount_warning(mp, "Cannot unmount: "
777 						  "%d namecache "
778 						  "references still "
779 						  "present",
780 						  ncp->nc_refs - 1);
781 			} else {
782 				mount_warning(mp, "Forced unmount: "
783 						  "%d namecache "
784 						  "references still "
785 						  "present",
786 						  ncp->nc_refs - 1);
787 				freeok = 0;
788 			}
789 		}
790 	}
791 
792 	/*
793 	 * Decomission our special mnt_syncer vnode.  This also stops
794 	 * the vnlru code.  If we are unable to unmount we recommission
795 	 * the vnode.
796 	 *
797 	 * Then sync the filesystem.
798 	 */
799 	if ((vp = mp->mnt_syncer) != NULL) {
800 		mp->mnt_syncer = NULL;
801 		atomic_set_int(&vp->v_refcnt, VREF_FINALIZE);
802 		vrele(vp);
803 	}
804 
805 	if (quickhalt == 0) {
806 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
807 			VFS_SYNC(mp, MNT_WAIT);
808 	}
809 
810 	/*
811 	 * nchandle records ref the mount structure.  Expect a count of 1
812 	 * (our mount->mnt_ncmountpt).
813 	 *
814 	 * Scans can get temporary refs on a mountpoint (thought really
815 	 * heavy duty stuff like cache_findmount() do not).
816 	 */
817 	if (mp->mnt_refs != 1)
818 		cache_clearmntcache();
819 	for (retry = 0; retry < 10 && mp->mnt_refs != 1; ++retry) {
820 		cache_unmounting(mp);
821 		tsleep(&mp->mnt_refs, 0, "mntbsy", hz / 10 + 1);
822 		cache_clearmntcache();
823 	}
824 	if (mp->mnt_refs != 1) {
825 		if ((flags & MNT_FORCE) == 0) {
826 			mount_warning(mp, "Cannot unmount: "
827 					  "%d mount refs still present",
828 					  mp->mnt_refs - 1);
829 			error = EBUSY;
830 		} else {
831 			mount_warning(mp, "Forced unmount: "
832 					  "%d mount refs still present",
833 					  mp->mnt_refs - 1);
834 			freeok = 0;
835 		}
836 	}
837 
838 	/*
839 	 * So far so good, sync the filesystem once more and
840 	 * call the VFS unmount code if the sync succeeds.
841 	 */
842 	if (error == 0 && quickhalt == 0) {
843 		if (mp->mnt_flag & MNT_RDONLY) {
844 			error = VFS_UNMOUNT(mp, flags);
845 		} else {
846 			error = VFS_SYNC(mp, MNT_WAIT);
847 			if ((error == 0) ||
848 			    (error == EOPNOTSUPP) || /* No sync */
849 			    (flags & MNT_FORCE)) {
850 				error = VFS_UNMOUNT(mp, flags);
851 			}
852 		}
853 	}
854 
855 	/*
856 	 * If an error occurred we can still recover, restoring the
857 	 * syncer vnode and misc flags.
858 	 */
859 	if (error) {
860 		if (mp->mnt_syncer == NULL)
861 			vfs_allocate_syncvnode(mp);
862 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
863 		mp->mnt_flag |= async_flag;
864 		lockmgr(&mp->mnt_lock, LK_RELEASE);
865 		if (mp->mnt_kern_flag & MNTK_MWAIT) {
866 			mp->mnt_kern_flag &= ~MNTK_MWAIT;
867 			wakeup(mp);
868 		}
869 		goto out;
870 	}
871 	/*
872 	 * Clean up any journals still associated with the mount after
873 	 * filesystem activity has ceased.
874 	 */
875 	journal_remove_all_journals(mp,
876 	    ((flags & MNT_FORCE) ? MC_JOURNAL_STOP_IMM : 0));
877 
878 	mountlist_remove(mp);
879 
880 	/*
881 	 * Remove any installed vnode ops here so the individual VFSs don't
882 	 * have to.
883 	 *
884 	 * mnt_refs should go to zero when we scrap mnt_ncmountpt.
885 	 *
886 	 * When quickhalting we have to keep these intact because the
887 	 * underlying vnodes have not been destroyed, and some might be
888 	 * dirty.
889 	 */
890 	if (quickhalt == 0) {
891 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
892 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
893 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
894 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
895 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
896 	}
897 
898 	if (mp->mnt_ncmountpt.ncp != NULL) {
899 		nch = mp->mnt_ncmountpt;
900 		cache_zero(&mp->mnt_ncmountpt);
901 		cache_clrmountpt(&nch);
902 		cache_drop(&nch);
903 	}
904 	if (mp->mnt_ncmounton.ncp != NULL) {
905 		cache_unmounting(mp);
906 		nch = mp->mnt_ncmounton;
907 		cache_zero(&mp->mnt_ncmounton);
908 		cache_clrmountpt(&nch);
909 		cache_drop(&nch);
910 	}
911 
912 	mp->mnt_vfc->vfc_refcount--;
913 
914 	/*
915 	 * If not quickhalting the mount, we expect there to be no
916 	 * vnodes left.
917 	 */
918 	if (quickhalt == 0 && !TAILQ_EMPTY(&mp->mnt_nvnodelist))
919 		panic("unmount: dangling vnode");
920 
921 	/*
922 	 * Release the lock
923 	 */
924 	lockmgr(&mp->mnt_lock, LK_RELEASE);
925 	if (mp->mnt_kern_flag & MNTK_MWAIT) {
926 		mp->mnt_kern_flag &= ~MNTK_MWAIT;
927 		wakeup(mp);
928 	}
929 
930 	/*
931 	 * If we reach here and freeok != 0 we must free the mount.
932 	 * mnt_refs should already have dropped to 0, so if it is not
933 	 * zero we must cycle the caches and wait.
934 	 *
935 	 * When we are satisfied that the mount has disconnected we can
936 	 * drop the hold on the mp that represented the mount (though the
937 	 * caller might actually have another, so the caller's drop may
938 	 * do the actual free).
939 	 */
940 	if (freeok) {
941 		if (mp->mnt_refs > 0)
942 			cache_clearmntcache();
943 		while (mp->mnt_refs > 0) {
944 			cache_unmounting(mp);
945 			wakeup(mp);
946 			tsleep(&mp->mnt_refs, 0, "umntrwait", hz / 10 + 1);
947 			cache_clearmntcache();
948 		}
949 		lwkt_reltoken(&mp->mnt_token);
950 		mount_drop(mp);
951 		mp = NULL;
952 	} else {
953 		cache_clearmntcache();
954 	}
955 	error = 0;
956 	KNOTE(&fs_klist, VQ_UNMOUNT);
957 out:
958 	if (mp)
959 		lwkt_reltoken(&mp->mnt_token);
960 	return (error);
961 }
962 
963 static
964 void
965 mount_warning(struct mount *mp, const char *ctl, ...)
966 {
967 	char *ptr;
968 	char *buf;
969 	__va_list va;
970 
971 	__va_start(va, ctl);
972 	if (cache_fullpath(NULL, &mp->mnt_ncmounton, NULL,
973 			   &ptr, &buf, 0) == 0) {
974 		kprintf("unmount(%s): ", ptr);
975 		kvprintf(ctl, va);
976 		kprintf("\n");
977 		kfree(buf, M_TEMP);
978 	} else {
979 		kprintf("unmount(%p", mp);
980 		if (mp->mnt_ncmounton.ncp && mp->mnt_ncmounton.ncp->nc_name)
981 			kprintf(",%s", mp->mnt_ncmounton.ncp->nc_name);
982 		kprintf("): ");
983 		kvprintf(ctl, va);
984 		kprintf("\n");
985 	}
986 	__va_end(va);
987 }
988 
989 /*
990  * Shim cache_fullpath() to handle the case where a process is chrooted into
991  * a subdirectory of a mount.  In this case if the root mount matches the
992  * process root directory's mount we have to specify the process's root
993  * directory instead of the mount point, because the mount point might
994  * be above the root directory.
995  */
996 static
997 int
998 mount_path(struct proc *p, struct mount *mp, char **rb, char **fb)
999 {
1000 	struct nchandle *nch;
1001 
1002 	if (p && p->p_fd->fd_nrdir.mount == mp)
1003 		nch = &p->p_fd->fd_nrdir;
1004 	else
1005 		nch = &mp->mnt_ncmountpt;
1006 	return(cache_fullpath(p, nch, NULL, rb, fb, 0));
1007 }
1008 
1009 /*
1010  * Sync each mounted filesystem.
1011  */
1012 
1013 #ifdef DEBUG
1014 static int syncprt = 0;
1015 SYSCTL_INT(_debug, OID_AUTO, syncprt, CTLFLAG_RW, &syncprt, 0, "");
1016 #endif /* DEBUG */
1017 
1018 static int sync_callback(struct mount *mp, void *data);
1019 
1020 int
1021 sys_sync(struct sync_args *uap)
1022 {
1023 	mountlist_scan(sync_callback, NULL, MNTSCAN_FORWARD);
1024 	return (0);
1025 }
1026 
1027 static
1028 int
1029 sync_callback(struct mount *mp, void *data __unused)
1030 {
1031 	int asyncflag;
1032 
1033 	if ((mp->mnt_flag & MNT_RDONLY) == 0) {
1034 		lwkt_gettoken(&mp->mnt_token);
1035 		asyncflag = mp->mnt_flag & MNT_ASYNC;
1036 		mp->mnt_flag &= ~MNT_ASYNC;
1037 		lwkt_reltoken(&mp->mnt_token);
1038 		vfs_msync(mp, MNT_NOWAIT);
1039 		VFS_SYNC(mp, MNT_NOWAIT);
1040 		lwkt_gettoken(&mp->mnt_token);
1041 		mp->mnt_flag |= asyncflag;
1042 		lwkt_reltoken(&mp->mnt_token);
1043 	}
1044 	return(0);
1045 }
1046 
1047 /* XXX PRISON: could be per prison flag */
1048 static int prison_quotas;
1049 #if 0
1050 SYSCTL_INT(_kern_prison, OID_AUTO, quotas, CTLFLAG_RW, &prison_quotas, 0, "");
1051 #endif
1052 
1053 /*
1054  *  quotactl_args(char *path, int fcmd, int uid, caddr_t arg)
1055  *
1056  * Change filesystem quotas.
1057  *
1058  * MPALMOSTSAFE
1059  */
1060 int
1061 sys_quotactl(struct quotactl_args *uap)
1062 {
1063 	struct nlookupdata nd;
1064 	struct thread *td;
1065 	struct mount *mp;
1066 	int error;
1067 
1068 	td = curthread;
1069 	if (td->td_ucred->cr_prison && !prison_quotas) {
1070 		error = EPERM;
1071 		goto done;
1072 	}
1073 
1074 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1075 	if (error == 0)
1076 		error = nlookup(&nd);
1077 	if (error == 0) {
1078 		mp = nd.nl_nch.mount;
1079 		error = VFS_QUOTACTL(mp, uap->cmd, uap->uid,
1080 				    uap->arg, nd.nl_cred);
1081 	}
1082 	nlookup_done(&nd);
1083 done:
1084 	return (error);
1085 }
1086 
1087 /*
1088  * mountctl(char *path, int op, int fd, const void *ctl, int ctllen,
1089  *		void *buf, int buflen)
1090  *
1091  * This function operates on a mount point and executes the specified
1092  * operation using the specified control data, and possibly returns data.
1093  *
1094  * The actual number of bytes stored in the result buffer is returned, 0
1095  * if none, otherwise an error is returned.
1096  *
1097  * MPALMOSTSAFE
1098  */
1099 int
1100 sys_mountctl(struct mountctl_args *uap)
1101 {
1102 	struct thread *td = curthread;
1103 	struct file *fp;
1104 	void *ctl = NULL;
1105 	void *buf = NULL;
1106 	char *path = NULL;
1107 	int error;
1108 
1109 	/*
1110 	 * Sanity and permissions checks.  We must be root.
1111 	 */
1112 	if (td->td_ucred->cr_prison != NULL)
1113 		return (EPERM);
1114 	if ((uap->op != MOUNTCTL_MOUNTFLAGS) &&
1115 	    (error = priv_check(td, PRIV_ROOT)) != 0)
1116 		return (error);
1117 
1118 	/*
1119 	 * Argument length checks
1120 	 */
1121 	if (uap->ctllen < 0 || uap->ctllen > 1024)
1122 		return (EINVAL);
1123 	if (uap->buflen < 0 || uap->buflen > 16 * 1024)
1124 		return (EINVAL);
1125 	if (uap->path == NULL)
1126 		return (EINVAL);
1127 
1128 	/*
1129 	 * Allocate the necessary buffers and copyin data
1130 	 */
1131 	path = objcache_get(namei_oc, M_WAITOK);
1132 	error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
1133 	if (error)
1134 		goto done;
1135 
1136 	if (uap->ctllen) {
1137 		ctl = kmalloc(uap->ctllen + 1, M_TEMP, M_WAITOK|M_ZERO);
1138 		error = copyin(uap->ctl, ctl, uap->ctllen);
1139 		if (error)
1140 			goto done;
1141 	}
1142 	if (uap->buflen)
1143 		buf = kmalloc(uap->buflen + 1, M_TEMP, M_WAITOK|M_ZERO);
1144 
1145 	/*
1146 	 * Validate the descriptor
1147 	 */
1148 	if (uap->fd >= 0) {
1149 		fp = holdfp(td, uap->fd, -1);
1150 		if (fp == NULL) {
1151 			error = EBADF;
1152 			goto done;
1153 		}
1154 	} else {
1155 		fp = NULL;
1156 	}
1157 
1158 	/*
1159 	 * Execute the internal kernel function and clean up.
1160 	 */
1161 	error = kern_mountctl(path, uap->op, fp, ctl, uap->ctllen,
1162 			      buf, uap->buflen, &uap->sysmsg_result);
1163 	if (fp)
1164 		dropfp(td, uap->fd, fp);
1165 	if (error == 0 && uap->sysmsg_result > 0)
1166 		error = copyout(buf, uap->buf, uap->sysmsg_result);
1167 done:
1168 	if (path)
1169 		objcache_put(namei_oc, path);
1170 	if (ctl)
1171 		kfree(ctl, M_TEMP);
1172 	if (buf)
1173 		kfree(buf, M_TEMP);
1174 	return (error);
1175 }
1176 
1177 /*
1178  * Execute a mount control operation by resolving the path to a mount point
1179  * and calling vop_mountctl().
1180  *
1181  * Use the mount point from the nch instead of the vnode so nullfs mounts
1182  * can properly spike the VOP.
1183  */
1184 int
1185 kern_mountctl(const char *path, int op, struct file *fp,
1186 		const void *ctl, int ctllen,
1187 		void *buf, int buflen, int *res)
1188 {
1189 	struct vnode *vp;
1190 	struct nlookupdata nd;
1191 	struct nchandle nch;
1192 	struct mount *mp;
1193 	int error;
1194 
1195 	*res = 0;
1196 	vp = NULL;
1197 	error = nlookup_init(&nd, path, UIO_SYSSPACE, NLC_FOLLOW);
1198 	if (error)
1199 		return (error);
1200 	error = nlookup(&nd);
1201 	if (error) {
1202 		nlookup_done(&nd);
1203 		return (error);
1204 	}
1205 	error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
1206 	if (error) {
1207 		nlookup_done(&nd);
1208 		return (error);
1209 	}
1210 
1211 	/*
1212 	 * Yes, all this is needed to use the nch.mount below, because
1213 	 * we must maintain a ref on the mount to avoid ripouts (e.g.
1214 	 * due to heavy mount/unmount use by synth or poudriere).
1215 	 */
1216 	nch = nd.nl_nch;
1217 	cache_zero(&nd.nl_nch);
1218 	cache_unlock(&nch);
1219 	nlookup_done(&nd);
1220 	vn_unlock(vp);
1221 
1222 	mp = nch.mount;
1223 
1224 	/*
1225 	 * Must be the root of the filesystem
1226 	 */
1227 	if ((vp->v_flag & (VROOT|VPFSROOT)) == 0) {
1228 		cache_drop(&nch);
1229 		vrele(vp);
1230 		return (EINVAL);
1231 	}
1232 	if (mp == NULL || mp->mnt_kern_flag & MNTK_UNMOUNT) {
1233 		kprintf("kern_mountctl: Warning, \"%s\" racing unmount\n",
1234 			path);
1235 		cache_drop(&nch);
1236 		vrele(vp);
1237 		return (EINVAL);
1238 	}
1239 	error = vop_mountctl(mp->mnt_vn_use_ops, vp, op, fp, ctl, ctllen,
1240 			     buf, buflen, res);
1241 	vrele(vp);
1242 	cache_drop(&nch);
1243 
1244 	return (error);
1245 }
1246 
1247 int
1248 kern_statfs(struct nlookupdata *nd, struct statfs *buf)
1249 {
1250 	struct thread *td = curthread;
1251 	struct proc *p = td->td_proc;
1252 	struct mount *mp;
1253 	struct statfs *sp;
1254 	char *fullpath, *freepath;
1255 	int error;
1256 
1257 	if ((error = nlookup(nd)) != 0)
1258 		return (error);
1259 	mp = nd->nl_nch.mount;
1260 	sp = &mp->mnt_stat;
1261 	if ((error = VFS_STATFS(mp, sp, nd->nl_cred)) != 0)
1262 		return (error);
1263 
1264 	error = mount_path(p, mp, &fullpath, &freepath);
1265 	if (error)
1266 		return(error);
1267 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1268 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1269 	kfree(freepath, M_TEMP);
1270 
1271 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1272 	bcopy(sp, buf, sizeof(*buf));
1273 	/* Only root should have access to the fsid's. */
1274 	if (priv_check(td, PRIV_ROOT))
1275 		buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
1276 	return (0);
1277 }
1278 
1279 /*
1280  * statfs_args(char *path, struct statfs *buf)
1281  *
1282  * Get filesystem statistics.
1283  */
1284 int
1285 sys_statfs(struct statfs_args *uap)
1286 {
1287 	struct nlookupdata nd;
1288 	struct statfs buf;
1289 	int error;
1290 
1291 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1292 	if (error == 0)
1293 		error = kern_statfs(&nd, &buf);
1294 	nlookup_done(&nd);
1295 	if (error == 0)
1296 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1297 	return (error);
1298 }
1299 
1300 int
1301 kern_fstatfs(int fd, struct statfs *buf)
1302 {
1303 	struct thread *td = curthread;
1304 	struct proc *p = td->td_proc;
1305 	struct file *fp;
1306 	struct mount *mp;
1307 	struct statfs *sp;
1308 	char *fullpath, *freepath;
1309 	int error;
1310 
1311 	KKASSERT(p);
1312 	if ((error = holdvnode(td, fd, &fp)) != 0)
1313 		return (error);
1314 
1315 	/*
1316 	 * Try to use mount info from any overlays rather than the
1317 	 * mount info for the underlying vnode, otherwise we will
1318 	 * fail when operating on null-mounted paths inside a chroot.
1319 	 */
1320 	if ((mp = fp->f_nchandle.mount) == NULL)
1321 		mp = ((struct vnode *)fp->f_data)->v_mount;
1322 	if (mp == NULL) {
1323 		error = EBADF;
1324 		goto done;
1325 	}
1326 	if (fp->f_cred == NULL) {
1327 		error = EINVAL;
1328 		goto done;
1329 	}
1330 	sp = &mp->mnt_stat;
1331 	if ((error = VFS_STATFS(mp, sp, fp->f_cred)) != 0)
1332 		goto done;
1333 
1334 	if ((error = mount_path(p, mp, &fullpath, &freepath)) != 0)
1335 		goto done;
1336 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1337 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1338 	kfree(freepath, M_TEMP);
1339 
1340 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1341 	bcopy(sp, buf, sizeof(*buf));
1342 
1343 	/* Only root should have access to the fsid's. */
1344 	if (priv_check(td, PRIV_ROOT))
1345 		buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
1346 	error = 0;
1347 done:
1348 	fdrop(fp);
1349 	return (error);
1350 }
1351 
1352 /*
1353  * fstatfs_args(int fd, struct statfs *buf)
1354  *
1355  * Get filesystem statistics.
1356  */
1357 int
1358 sys_fstatfs(struct fstatfs_args *uap)
1359 {
1360 	struct statfs buf;
1361 	int error;
1362 
1363 	error = kern_fstatfs(uap->fd, &buf);
1364 
1365 	if (error == 0)
1366 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1367 	return (error);
1368 }
1369 
1370 int
1371 kern_statvfs(struct nlookupdata *nd, struct statvfs *buf)
1372 {
1373 	struct mount *mp;
1374 	struct statvfs *sp;
1375 	int error;
1376 
1377 	if ((error = nlookup(nd)) != 0)
1378 		return (error);
1379 	mp = nd->nl_nch.mount;
1380 	sp = &mp->mnt_vstat;
1381 	if ((error = VFS_STATVFS(mp, sp, nd->nl_cred)) != 0)
1382 		return (error);
1383 
1384 	sp->f_flag = 0;
1385 	if (mp->mnt_flag & MNT_RDONLY)
1386 		sp->f_flag |= ST_RDONLY;
1387 	if (mp->mnt_flag & MNT_NOSUID)
1388 		sp->f_flag |= ST_NOSUID;
1389 	bcopy(sp, buf, sizeof(*buf));
1390 	return (0);
1391 }
1392 
1393 /*
1394  * statfs_args(char *path, struct statfs *buf)
1395  *
1396  * Get filesystem statistics.
1397  */
1398 int
1399 sys_statvfs(struct statvfs_args *uap)
1400 {
1401 	struct nlookupdata nd;
1402 	struct statvfs buf;
1403 	int error;
1404 
1405 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1406 	if (error == 0)
1407 		error = kern_statvfs(&nd, &buf);
1408 	nlookup_done(&nd);
1409 	if (error == 0)
1410 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1411 	return (error);
1412 }
1413 
1414 int
1415 kern_fstatvfs(int fd, struct statvfs *buf)
1416 {
1417 	struct thread *td = curthread;
1418 	struct file *fp;
1419 	struct mount *mp;
1420 	struct statvfs *sp;
1421 	int error;
1422 
1423 	if ((error = holdvnode(td, fd, &fp)) != 0)
1424 		return (error);
1425 	if ((mp = fp->f_nchandle.mount) == NULL)
1426 		mp = ((struct vnode *)fp->f_data)->v_mount;
1427 	if (mp == NULL) {
1428 		error = EBADF;
1429 		goto done;
1430 	}
1431 	if (fp->f_cred == NULL) {
1432 		error = EINVAL;
1433 		goto done;
1434 	}
1435 	sp = &mp->mnt_vstat;
1436 	if ((error = VFS_STATVFS(mp, sp, fp->f_cred)) != 0)
1437 		goto done;
1438 
1439 	sp->f_flag = 0;
1440 	if (mp->mnt_flag & MNT_RDONLY)
1441 		sp->f_flag |= ST_RDONLY;
1442 	if (mp->mnt_flag & MNT_NOSUID)
1443 		sp->f_flag |= ST_NOSUID;
1444 
1445 	bcopy(sp, buf, sizeof(*buf));
1446 	error = 0;
1447 done:
1448 	fdrop(fp);
1449 	return (error);
1450 }
1451 
1452 /*
1453  * fstatfs_args(int fd, struct statfs *buf)
1454  *
1455  * Get filesystem statistics.
1456  */
1457 int
1458 sys_fstatvfs(struct fstatvfs_args *uap)
1459 {
1460 	struct statvfs buf;
1461 	int error;
1462 
1463 	error = kern_fstatvfs(uap->fd, &buf);
1464 
1465 	if (error == 0)
1466 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1467 	return (error);
1468 }
1469 
1470 /*
1471  * getfsstat_args(struct statfs *buf, long bufsize, int flags)
1472  *
1473  * Get statistics on all filesystems.
1474  */
1475 
1476 struct getfsstat_info {
1477 	struct statfs *sfsp;
1478 	long count;
1479 	long maxcount;
1480 	int error;
1481 	int flags;
1482 	struct thread *td;
1483 };
1484 
1485 static int getfsstat_callback(struct mount *, void *);
1486 
1487 int
1488 sys_getfsstat(struct getfsstat_args *uap)
1489 {
1490 	struct thread *td = curthread;
1491 	struct getfsstat_info info;
1492 
1493 	bzero(&info, sizeof(info));
1494 
1495 	info.maxcount = uap->bufsize / sizeof(struct statfs);
1496 	info.sfsp = uap->buf;
1497 	info.count = 0;
1498 	info.flags = uap->flags;
1499 	info.td = td;
1500 
1501 	mountlist_scan(getfsstat_callback, &info, MNTSCAN_FORWARD);
1502 	if (info.sfsp && info.count > info.maxcount)
1503 		uap->sysmsg_result = info.maxcount;
1504 	else
1505 		uap->sysmsg_result = info.count;
1506 	return (info.error);
1507 }
1508 
1509 static int
1510 getfsstat_callback(struct mount *mp, void *data)
1511 {
1512 	struct getfsstat_info *info = data;
1513 	struct statfs *sp;
1514 	char *freepath;
1515 	char *fullpath;
1516 	int error;
1517 
1518 	if (info->sfsp && info->count < info->maxcount) {
1519 		if (info->td->td_proc &&
1520 		    !chroot_visible_mnt(mp, info->td->td_proc)) {
1521 			return(0);
1522 		}
1523 		sp = &mp->mnt_stat;
1524 
1525 		/*
1526 		 * If MNT_NOWAIT or MNT_LAZY is specified, do not
1527 		 * refresh the fsstat cache. MNT_NOWAIT or MNT_LAZY
1528 		 * overrides MNT_WAIT.
1529 		 */
1530 		if (((info->flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
1531 		    (info->flags & MNT_WAIT)) &&
1532 		    (error = VFS_STATFS(mp, sp, info->td->td_ucred))) {
1533 			return(0);
1534 		}
1535 		sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1536 
1537 		error = mount_path(info->td->td_proc, mp, &fullpath, &freepath);
1538 		if (error) {
1539 			info->error = error;
1540 			return(-1);
1541 		}
1542 		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1543 		strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1544 		kfree(freepath, M_TEMP);
1545 
1546 		error = copyout(sp, info->sfsp, sizeof(*sp));
1547 		if (error) {
1548 			info->error = error;
1549 			return (-1);
1550 		}
1551 		++info->sfsp;
1552 	}
1553 	info->count++;
1554 	return(0);
1555 }
1556 
1557 /*
1558  * getvfsstat_args(struct statfs *buf, struct statvfs *vbuf,
1559 		   long bufsize, int flags)
1560  *
1561  * Get statistics on all filesystems.
1562  */
1563 
1564 struct getvfsstat_info {
1565 	struct statfs *sfsp;
1566 	struct statvfs *vsfsp;
1567 	long count;
1568 	long maxcount;
1569 	int error;
1570 	int flags;
1571 	struct thread *td;
1572 };
1573 
1574 static int getvfsstat_callback(struct mount *, void *);
1575 
1576 int
1577 sys_getvfsstat(struct getvfsstat_args *uap)
1578 {
1579 	struct thread *td = curthread;
1580 	struct getvfsstat_info info;
1581 
1582 	bzero(&info, sizeof(info));
1583 
1584 	info.maxcount = uap->vbufsize / sizeof(struct statvfs);
1585 	info.sfsp = uap->buf;
1586 	info.vsfsp = uap->vbuf;
1587 	info.count = 0;
1588 	info.flags = uap->flags;
1589 	info.td = td;
1590 
1591 	mountlist_scan(getvfsstat_callback, &info, MNTSCAN_FORWARD);
1592 	if (info.vsfsp && info.count > info.maxcount)
1593 		uap->sysmsg_result = info.maxcount;
1594 	else
1595 		uap->sysmsg_result = info.count;
1596 	return (info.error);
1597 }
1598 
1599 static int
1600 getvfsstat_callback(struct mount *mp, void *data)
1601 {
1602 	struct getvfsstat_info *info = data;
1603 	struct statfs *sp;
1604 	struct statvfs *vsp;
1605 	char *freepath;
1606 	char *fullpath;
1607 	int error;
1608 
1609 	if (info->vsfsp && info->count < info->maxcount) {
1610 		if (info->td->td_proc &&
1611 		    !chroot_visible_mnt(mp, info->td->td_proc)) {
1612 			return(0);
1613 		}
1614 		sp = &mp->mnt_stat;
1615 		vsp = &mp->mnt_vstat;
1616 
1617 		/*
1618 		 * If MNT_NOWAIT or MNT_LAZY is specified, do not
1619 		 * refresh the fsstat cache. MNT_NOWAIT or MNT_LAZY
1620 		 * overrides MNT_WAIT.
1621 		 */
1622 		if (((info->flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
1623 		    (info->flags & MNT_WAIT)) &&
1624 		    (error = VFS_STATFS(mp, sp, info->td->td_ucred))) {
1625 			return(0);
1626 		}
1627 		sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1628 
1629 		if (((info->flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
1630 		    (info->flags & MNT_WAIT)) &&
1631 		    (error = VFS_STATVFS(mp, vsp, info->td->td_ucred))) {
1632 			return(0);
1633 		}
1634 		vsp->f_flag = 0;
1635 		if (mp->mnt_flag & MNT_RDONLY)
1636 			vsp->f_flag |= ST_RDONLY;
1637 		if (mp->mnt_flag & MNT_NOSUID)
1638 			vsp->f_flag |= ST_NOSUID;
1639 
1640 		error = mount_path(info->td->td_proc, mp, &fullpath, &freepath);
1641 		if (error) {
1642 			info->error = error;
1643 			return(-1);
1644 		}
1645 		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1646 		strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1647 		kfree(freepath, M_TEMP);
1648 
1649 		error = copyout(sp, info->sfsp, sizeof(*sp));
1650 		if (error == 0)
1651 			error = copyout(vsp, info->vsfsp, sizeof(*vsp));
1652 		if (error) {
1653 			info->error = error;
1654 			return (-1);
1655 		}
1656 		++info->sfsp;
1657 		++info->vsfsp;
1658 	}
1659 	info->count++;
1660 	return(0);
1661 }
1662 
1663 
1664 /*
1665  * fchdir_args(int fd)
1666  *
1667  * Change current working directory to a given file descriptor.
1668  */
1669 int
1670 sys_fchdir(struct fchdir_args *uap)
1671 {
1672 	struct thread *td = curthread;
1673 	struct proc *p = td->td_proc;
1674 	struct filedesc *fdp = p->p_fd;
1675 	struct vnode *vp, *ovp;
1676 	struct mount *mp;
1677 	struct file *fp;
1678 	struct nchandle nch, onch, tnch;
1679 	int error;
1680 
1681 	if ((error = holdvnode(td, uap->fd, &fp)) != 0)
1682 		return (error);
1683 	lwkt_gettoken(&p->p_token);
1684 	vp = (struct vnode *)fp->f_data;
1685 	vref(vp);
1686 	vn_lock(vp, LK_SHARED | LK_RETRY);
1687 	if (fp->f_nchandle.ncp == NULL)
1688 		error = ENOTDIR;
1689 	else
1690 		error = checkvp_chdir(vp, td);
1691 	if (error) {
1692 		vput(vp);
1693 		goto done;
1694 	}
1695 	cache_copy(&fp->f_nchandle, &nch);
1696 
1697 	/*
1698 	 * If the ncp has become a mount point, traverse through
1699 	 * the mount point.
1700 	 */
1701 
1702 	while (!error && (nch.ncp->nc_flag & NCF_ISMOUNTPT) &&
1703 	       (mp = cache_findmount(&nch)) != NULL
1704 	) {
1705 		error = nlookup_mp(mp, &tnch);
1706 		if (error == 0) {
1707 			cache_unlock(&tnch);	/* leave ref intact */
1708 			vput(vp);
1709 			vp = tnch.ncp->nc_vp;
1710 			error = vget(vp, LK_SHARED);
1711 			KKASSERT(error == 0);
1712 			cache_drop(&nch);
1713 			nch = tnch;
1714 		}
1715 		cache_dropmount(mp);
1716 	}
1717 	if (error == 0) {
1718 		spin_lock(&fdp->fd_spin);
1719 		ovp = fdp->fd_cdir;
1720 		onch = fdp->fd_ncdir;
1721 		fdp->fd_cdir = vp;
1722 		fdp->fd_ncdir = nch;
1723 		spin_unlock(&fdp->fd_spin);
1724 		vn_unlock(vp);		/* leave ref intact */
1725 		cache_drop(&onch);
1726 		vrele(ovp);
1727 	} else {
1728 		cache_drop(&nch);
1729 		vput(vp);
1730 	}
1731 	fdrop(fp);
1732 done:
1733 	lwkt_reltoken(&p->p_token);
1734 	return (error);
1735 }
1736 
1737 int
1738 kern_chdir(struct nlookupdata *nd)
1739 {
1740 	struct thread *td = curthread;
1741 	struct proc *p = td->td_proc;
1742 	struct filedesc *fdp = p->p_fd;
1743 	struct vnode *vp, *ovp;
1744 	struct nchandle onch;
1745 	int error;
1746 
1747 	nd->nl_flags |= NLC_SHAREDLOCK;
1748 	if ((error = nlookup(nd)) != 0)
1749 		return (error);
1750 	if ((vp = nd->nl_nch.ncp->nc_vp) == NULL)
1751 		return (ENOENT);
1752 	if ((error = vget(vp, LK_SHARED)) != 0)
1753 		return (error);
1754 
1755 	lwkt_gettoken(&p->p_token);
1756 	error = checkvp_chdir(vp, td);
1757 	vn_unlock(vp);
1758 	if (error == 0) {
1759 		spin_lock(&fdp->fd_spin);
1760 		ovp = fdp->fd_cdir;
1761 		onch = fdp->fd_ncdir;
1762 		fdp->fd_ncdir = nd->nl_nch;
1763 		fdp->fd_cdir = vp;
1764 		spin_unlock(&fdp->fd_spin);
1765 		cache_unlock(&nd->nl_nch);	/* leave reference intact */
1766 		cache_drop(&onch);
1767 		vrele(ovp);
1768 		cache_zero(&nd->nl_nch);
1769 	} else {
1770 		vrele(vp);
1771 	}
1772 	lwkt_reltoken(&p->p_token);
1773 	return (error);
1774 }
1775 
1776 /*
1777  * chdir_args(char *path)
1778  *
1779  * Change current working directory (``.'').
1780  */
1781 int
1782 sys_chdir(struct chdir_args *uap)
1783 {
1784 	struct nlookupdata nd;
1785 	int error;
1786 
1787 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1788 	if (error == 0)
1789 		error = kern_chdir(&nd);
1790 	nlookup_done(&nd);
1791 	return (error);
1792 }
1793 
1794 /*
1795  * Helper function for raised chroot(2) security function:  Refuse if
1796  * any filedescriptors are open directories.
1797  */
1798 static int
1799 chroot_refuse_vdir_fds(thread_t td, struct filedesc *fdp)
1800 {
1801 	struct vnode *vp;
1802 	struct file *fp;
1803 	int error;
1804 	int fd;
1805 
1806 	for (fd = 0; fd < fdp->fd_nfiles ; fd++) {
1807 		if ((error = holdvnode(td, fd, &fp)) != 0)
1808 			continue;
1809 		vp = (struct vnode *)fp->f_data;
1810 		if (vp->v_type != VDIR) {
1811 			fdrop(fp);
1812 			continue;
1813 		}
1814 		fdrop(fp);
1815 		return(EPERM);
1816 	}
1817 	return (0);
1818 }
1819 
1820 /*
1821  * This sysctl determines if we will allow a process to chroot(2) if it
1822  * has a directory open:
1823  *	0: disallowed for all processes.
1824  *	1: allowed for processes that were not already chroot(2)'ed.
1825  *	2: allowed for all processes.
1826  */
1827 
1828 static int chroot_allow_open_directories = 1;
1829 
1830 SYSCTL_INT(_kern, OID_AUTO, chroot_allow_open_directories, CTLFLAG_RW,
1831      &chroot_allow_open_directories, 0, "");
1832 
1833 /*
1834  * chroot to the specified namecache entry.  We obtain the vp from the
1835  * namecache data.  The passed ncp must be locked and referenced and will
1836  * remain locked and referenced on return.
1837  */
1838 int
1839 kern_chroot(struct nchandle *nch)
1840 {
1841 	struct thread *td = curthread;
1842 	struct proc *p = td->td_proc;
1843 	struct filedesc *fdp = p->p_fd;
1844 	struct vnode *vp;
1845 	int error;
1846 
1847 	/*
1848 	 * Only privileged user can chroot
1849 	 */
1850 	error = priv_check_cred(td->td_ucred, PRIV_VFS_CHROOT, 0);
1851 	if (error)
1852 		return (error);
1853 
1854 	/*
1855 	 * Disallow open directory descriptors (fchdir() breakouts).
1856 	 */
1857 	if (chroot_allow_open_directories == 0 ||
1858 	   (chroot_allow_open_directories == 1 && fdp->fd_rdir != rootvnode)) {
1859 		if ((error = chroot_refuse_vdir_fds(td, fdp)) != 0)
1860 			return (error);
1861 	}
1862 	if ((vp = nch->ncp->nc_vp) == NULL)
1863 		return (ENOENT);
1864 
1865 	if ((error = vget(vp, LK_SHARED)) != 0)
1866 		return (error);
1867 
1868 	/*
1869 	 * Check the validity of vp as a directory to change to and
1870 	 * associate it with rdir/jdir.
1871 	 */
1872 	error = checkvp_chdir(vp, td);
1873 	vn_unlock(vp);			/* leave reference intact */
1874 	if (error == 0) {
1875 		lwkt_gettoken(&p->p_token);
1876 		vrele(fdp->fd_rdir);
1877 		fdp->fd_rdir = vp;	/* reference inherited by fd_rdir */
1878 		cache_drop(&fdp->fd_nrdir);
1879 		cache_copy(nch, &fdp->fd_nrdir);
1880 		if (fdp->fd_jdir == NULL) {
1881 			fdp->fd_jdir = vp;
1882 			vref(fdp->fd_jdir);
1883 			cache_copy(nch, &fdp->fd_njdir);
1884 		}
1885 		if ((p->p_flags & P_DIDCHROOT) == 0) {
1886 			p->p_flags |= P_DIDCHROOT;
1887 			if (p->p_depth <= 65535 - 32)
1888 				p->p_depth += 32;
1889 		}
1890 		lwkt_reltoken(&p->p_token);
1891 	} else {
1892 		vrele(vp);
1893 	}
1894 	return (error);
1895 }
1896 
1897 /*
1898  * chroot_args(char *path)
1899  *
1900  * Change notion of root (``/'') directory.
1901  */
1902 int
1903 sys_chroot(struct chroot_args *uap)
1904 {
1905 	struct thread *td __debugvar = curthread;
1906 	struct nlookupdata nd;
1907 	int error;
1908 
1909 	KKASSERT(td->td_proc);
1910 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1911 	if (error == 0) {
1912 		nd.nl_flags |= NLC_EXEC;
1913 		error = nlookup(&nd);
1914 		if (error == 0)
1915 			error = kern_chroot(&nd.nl_nch);
1916 	}
1917 	nlookup_done(&nd);
1918 	return(error);
1919 }
1920 
1921 int
1922 sys_chroot_kernel(struct chroot_kernel_args *uap)
1923 {
1924 	struct thread *td = curthread;
1925 	struct nlookupdata nd;
1926 	struct nchandle *nch;
1927 	struct vnode *vp;
1928 	int error;
1929 
1930 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1931 	if (error)
1932 		goto error_nond;
1933 
1934 	error = nlookup(&nd);
1935 	if (error)
1936 		goto error_out;
1937 
1938 	nch = &nd.nl_nch;
1939 
1940 	error = priv_check_cred(td->td_ucred, PRIV_VFS_CHROOT, 0);
1941 	if (error)
1942 		goto error_out;
1943 
1944 	if ((vp = nch->ncp->nc_vp) == NULL) {
1945 		error = ENOENT;
1946 		goto error_out;
1947 	}
1948 
1949 	if ((error = cache_vref(nch, nd.nl_cred, &vp)) != 0)
1950 		goto error_out;
1951 
1952 	kprintf("chroot_kernel: set new rootnch/rootvnode to %s\n", uap->path);
1953 	vfs_cache_setroot(vp, cache_hold(nch));
1954 
1955 error_out:
1956 	nlookup_done(&nd);
1957 error_nond:
1958 	return(error);
1959 }
1960 
1961 /*
1962  * Common routine for chroot and chdir.  Given a locked, referenced vnode,
1963  * determine whether it is legal to chdir to the vnode.  The vnode's state
1964  * is not changed by this call.
1965  */
1966 static int
1967 checkvp_chdir(struct vnode *vp, struct thread *td)
1968 {
1969 	int error;
1970 
1971 	if (vp->v_type != VDIR)
1972 		error = ENOTDIR;
1973 	else
1974 		error = VOP_EACCESS(vp, VEXEC, td->td_ucred);
1975 	return (error);
1976 }
1977 
1978 int
1979 kern_open(struct nlookupdata *nd, int oflags, int mode, int *res)
1980 {
1981 	struct thread *td = curthread;
1982 	struct proc *p = td->td_proc;
1983 	struct lwp *lp = td->td_lwp;
1984 	struct filedesc *fdp = p->p_fd;
1985 	int cmode, flags;
1986 	struct file *nfp;
1987 	struct file *fp;
1988 	struct vnode *vp;
1989 	int type, indx, error = 0;
1990 	struct flock lf;
1991 
1992 	if ((oflags & O_ACCMODE) == O_ACCMODE)
1993 		return (EINVAL);
1994 	flags = FFLAGS(oflags);
1995 	error = falloc(lp, &nfp, NULL);
1996 	if (error)
1997 		return (error);
1998 	fp = nfp;
1999 	cmode = ((mode &~ fdp->fd_cmask) & ALLPERMS) & ~S_ISTXT;
2000 
2001 	/*
2002 	 * XXX p_dupfd is a real mess.  It allows a device to return a
2003 	 * file descriptor to be duplicated rather then doing the open
2004 	 * itself.
2005 	 */
2006 	lp->lwp_dupfd = -1;
2007 
2008 	/*
2009 	 * Call vn_open() to do the lookup and assign the vnode to the
2010 	 * file pointer.  vn_open() does not change the ref count on fp
2011 	 * and the vnode, on success, will be inherited by the file pointer
2012 	 * and unlocked.
2013 	 *
2014 	 * Request a shared lock on the vnode if possible.
2015 	 *
2016 	 * Executable binaries can race VTEXT against O_RDWR opens, so
2017 	 * use an exclusive lock for O_RDWR opens as well.
2018 	 *
2019 	 * NOTE: We need a flag to separate terminal vnode locking from
2020 	 *	 parent locking.  O_CREAT needs parent locking, but O_TRUNC
2021 	 *	 and O_RDWR only need to lock the terminal vnode exclusively.
2022 	 */
2023 	nd->nl_flags |= NLC_LOCKVP;
2024 	if ((flags & (O_CREAT|O_TRUNC|O_RDWR)) == 0)
2025 		nd->nl_flags |= NLC_SHAREDLOCK;
2026 
2027 	error = vn_open(nd, fp, flags, cmode);
2028 	nlookup_done(nd);
2029 
2030 	if (error) {
2031 		/*
2032 		 * handle special fdopen() case.  bleh.  dupfdopen() is
2033 		 * responsible for dropping the old contents of ofiles[indx]
2034 		 * if it succeeds.
2035 		 *
2036 		 * Note that fsetfd() will add a ref to fp which represents
2037 		 * the fd_files[] assignment.  We must still drop our
2038 		 * reference.
2039 		 */
2040 		if ((error == ENODEV || error == ENXIO) && lp->lwp_dupfd >= 0) {
2041 			if (fdalloc(p, 0, &indx) == 0) {
2042 				error = dupfdopen(td, indx, lp->lwp_dupfd, flags, error);
2043 				if (error == 0) {
2044 					*res = indx;
2045 					fdrop(fp);	/* our ref */
2046 					return (0);
2047 				}
2048 				fsetfd(fdp, NULL, indx);
2049 			}
2050 		}
2051 		fdrop(fp);	/* our ref */
2052 		if (error == ERESTART)
2053 			error = EINTR;
2054 		return (error);
2055 	}
2056 
2057 	/*
2058 	 * ref the vnode for ourselves so it can't be ripped out from under
2059 	 * is.  XXX need an ND flag to request that the vnode be returned
2060 	 * anyway.
2061 	 *
2062 	 * Reserve a file descriptor but do not assign it until the open
2063 	 * succeeds.
2064 	 */
2065 	vp = (struct vnode *)fp->f_data;
2066 	vref(vp);
2067 	if ((error = fdalloc(p, 0, &indx)) != 0) {
2068 		fdrop(fp);
2069 		vrele(vp);
2070 		return (error);
2071 	}
2072 
2073 	/*
2074 	 * If no error occurs the vp will have been assigned to the file
2075 	 * pointer.
2076 	 */
2077 	lp->lwp_dupfd = 0;
2078 
2079 	if (flags & (O_EXLOCK | O_SHLOCK)) {
2080 		lf.l_whence = SEEK_SET;
2081 		lf.l_start = 0;
2082 		lf.l_len = 0;
2083 		if (flags & O_EXLOCK)
2084 			lf.l_type = F_WRLCK;
2085 		else
2086 			lf.l_type = F_RDLCK;
2087 		if (flags & FNONBLOCK)
2088 			type = 0;
2089 		else
2090 			type = F_WAIT;
2091 
2092 		if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0) {
2093 			/*
2094 			 * lock request failed.  Clean up the reserved
2095 			 * descriptor.
2096 			 */
2097 			vrele(vp);
2098 			fsetfd(fdp, NULL, indx);
2099 			fdrop(fp);
2100 			return (error);
2101 		}
2102 		atomic_set_int(&fp->f_flag, FHASLOCK); /* race ok */
2103 	}
2104 #if 0
2105 	/*
2106 	 * Assert that all regular file vnodes were created with a object.
2107 	 */
2108 	KASSERT(vp->v_type != VREG || vp->v_object != NULL,
2109 		("open: regular file has no backing object after vn_open"));
2110 #endif
2111 
2112 	vrele(vp);
2113 
2114 	/*
2115 	 * release our private reference, leaving the one associated with the
2116 	 * descriptor table intact.
2117 	 */
2118 	if (oflags & O_CLOEXEC)
2119 		fdp->fd_files[indx].fileflags |= UF_EXCLOSE;
2120 	fsetfd(fdp, fp, indx);
2121 	fdrop(fp);
2122 	*res = indx;
2123 
2124 	return (error);
2125 }
2126 
2127 /*
2128  * open_args(char *path, int flags, int mode)
2129  *
2130  * Check permissions, allocate an open file structure,
2131  * and call the device open routine if any.
2132  */
2133 int
2134 sys_open(struct open_args *uap)
2135 {
2136 	struct nlookupdata nd;
2137 	int error;
2138 
2139 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2140 	if (error == 0) {
2141 		error = kern_open(&nd, uap->flags,
2142 				    uap->mode, &uap->sysmsg_result);
2143 	}
2144 	nlookup_done(&nd);
2145 	return (error);
2146 }
2147 
2148 /*
2149  * openat_args(int fd, char *path, int flags, int mode)
2150  */
2151 int
2152 sys_openat(struct openat_args *uap)
2153 {
2154 	struct nlookupdata nd;
2155 	int error;
2156 	struct file *fp;
2157 
2158 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2159 	if (error == 0) {
2160 		error = kern_open(&nd, uap->flags, uap->mode,
2161 					&uap->sysmsg_result);
2162 	}
2163 	nlookup_done_at(&nd, fp);
2164 	return (error);
2165 }
2166 
2167 int
2168 kern_mknod(struct nlookupdata *nd, int mode, int rmajor, int rminor)
2169 {
2170 	struct thread *td = curthread;
2171 	struct proc *p = td->td_proc;
2172 	struct vnode *vp;
2173 	struct vattr vattr;
2174 	int error;
2175 	int whiteout = 0;
2176 
2177 	KKASSERT(p);
2178 
2179 	VATTR_NULL(&vattr);
2180 	vattr.va_mode = (mode & ALLPERMS) &~ p->p_fd->fd_cmask;
2181 	vattr.va_rmajor = rmajor;
2182 	vattr.va_rminor = rminor;
2183 
2184 	switch (mode & S_IFMT) {
2185 	case S_IFMT:	/* used by badsect to flag bad sectors */
2186 		error = priv_check_cred(td->td_ucred, PRIV_VFS_MKNOD_BAD, 0);
2187 		vattr.va_type = VBAD;
2188 		break;
2189 	case S_IFCHR:
2190 		error = priv_check(td, PRIV_VFS_MKNOD_DEV);
2191 		vattr.va_type = VCHR;
2192 		break;
2193 	case S_IFBLK:
2194 		error = priv_check(td, PRIV_VFS_MKNOD_DEV);
2195 		vattr.va_type = VBLK;
2196 		break;
2197 	case S_IFWHT:
2198 		error = priv_check_cred(td->td_ucred, PRIV_VFS_MKNOD_WHT, 0);
2199 		whiteout = 1;
2200 		break;
2201 	case S_IFDIR:	/* special directories support for HAMMER */
2202 		error = priv_check_cred(td->td_ucred, PRIV_VFS_MKNOD_DIR, 0);
2203 		vattr.va_type = VDIR;
2204 		break;
2205 	default:
2206 		error = EINVAL;
2207 		break;
2208 	}
2209 
2210 	if (error)
2211 		return (error);
2212 
2213 	bwillinode(1);
2214 	nd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2215 	if ((error = nlookup(nd)) != 0)
2216 		return (error);
2217 	if (nd->nl_nch.ncp->nc_vp)
2218 		return (EEXIST);
2219 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2220 		return (error);
2221 
2222 	if (whiteout) {
2223 		error = VOP_NWHITEOUT(&nd->nl_nch, nd->nl_dvp,
2224 				      nd->nl_cred, NAMEI_CREATE);
2225 	} else {
2226 		vp = NULL;
2227 		error = VOP_NMKNOD(&nd->nl_nch, nd->nl_dvp,
2228 				   &vp, nd->nl_cred, &vattr);
2229 		if (error == 0)
2230 			vput(vp);
2231 	}
2232 	return (error);
2233 }
2234 
2235 /*
2236  * mknod_args(char *path, int mode, int dev)
2237  *
2238  * Create a special file.
2239  */
2240 int
2241 sys_mknod(struct mknod_args *uap)
2242 {
2243 	struct nlookupdata nd;
2244 	int error;
2245 
2246 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2247 	if (error == 0) {
2248 		error = kern_mknod(&nd, uap->mode,
2249 				   umajor(uap->dev), uminor(uap->dev));
2250 	}
2251 	nlookup_done(&nd);
2252 	return (error);
2253 }
2254 
2255 /*
2256  * mknodat_args(int fd, char *path, mode_t mode, dev_t dev)
2257  *
2258  * Create a special file.  The path is relative to the directory associated
2259  * with fd.
2260  */
2261 int
2262 sys_mknodat(struct mknodat_args *uap)
2263 {
2264 	struct nlookupdata nd;
2265 	struct file *fp;
2266 	int error;
2267 
2268 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2269 	if (error == 0) {
2270 		error = kern_mknod(&nd, uap->mode,
2271 				   umajor(uap->dev), uminor(uap->dev));
2272 	}
2273 	nlookup_done_at(&nd, fp);
2274 	return (error);
2275 }
2276 
2277 int
2278 kern_mkfifo(struct nlookupdata *nd, int mode)
2279 {
2280 	struct thread *td = curthread;
2281 	struct proc *p = td->td_proc;
2282 	struct vattr vattr;
2283 	struct vnode *vp;
2284 	int error;
2285 
2286 	bwillinode(1);
2287 
2288 	nd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2289 	if ((error = nlookup(nd)) != 0)
2290 		return (error);
2291 	if (nd->nl_nch.ncp->nc_vp)
2292 		return (EEXIST);
2293 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2294 		return (error);
2295 
2296 	VATTR_NULL(&vattr);
2297 	vattr.va_type = VFIFO;
2298 	vattr.va_mode = (mode & ALLPERMS) &~ p->p_fd->fd_cmask;
2299 	vp = NULL;
2300 	error = VOP_NMKNOD(&nd->nl_nch, nd->nl_dvp, &vp, nd->nl_cred, &vattr);
2301 	if (error == 0)
2302 		vput(vp);
2303 	return (error);
2304 }
2305 
2306 /*
2307  * mkfifo_args(char *path, int mode)
2308  *
2309  * Create a named pipe.
2310  */
2311 int
2312 sys_mkfifo(struct mkfifo_args *uap)
2313 {
2314 	struct nlookupdata nd;
2315 	int error;
2316 
2317 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2318 	if (error == 0)
2319 		error = kern_mkfifo(&nd, uap->mode);
2320 	nlookup_done(&nd);
2321 	return (error);
2322 }
2323 
2324 /*
2325  * mkfifoat_args(int fd, char *path, mode_t mode)
2326  *
2327  * Create a named pipe.  The path is relative to the directory associated
2328  * with fd.
2329  */
2330 int
2331 sys_mkfifoat(struct mkfifoat_args *uap)
2332 {
2333 	struct nlookupdata nd;
2334 	struct file *fp;
2335 	int error;
2336 
2337 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2338 	if (error == 0)
2339 		error = kern_mkfifo(&nd, uap->mode);
2340 	nlookup_done_at(&nd, fp);
2341 	return (error);
2342 }
2343 
2344 static int hardlink_check_uid = 0;
2345 SYSCTL_INT(_security, OID_AUTO, hardlink_check_uid, CTLFLAG_RW,
2346     &hardlink_check_uid, 0,
2347     "Unprivileged processes cannot create hard links to files owned by other "
2348     "users");
2349 static int hardlink_check_gid = 0;
2350 SYSCTL_INT(_security, OID_AUTO, hardlink_check_gid, CTLFLAG_RW,
2351     &hardlink_check_gid, 0,
2352     "Unprivileged processes cannot create hard links to files owned by other "
2353     "groups");
2354 
2355 static int
2356 can_hardlink(struct vnode *vp, struct thread *td, struct ucred *cred)
2357 {
2358 	struct vattr va;
2359 	int error;
2360 
2361 	/*
2362 	 * Shortcut if disabled
2363 	 */
2364 	if (hardlink_check_uid == 0 && hardlink_check_gid == 0)
2365 		return (0);
2366 
2367 	/*
2368 	 * Privileged user can always hardlink
2369 	 */
2370 	if (priv_check_cred(cred, PRIV_VFS_LINK, 0) == 0)
2371 		return (0);
2372 
2373 	/*
2374 	 * Otherwise only if the originating file is owned by the
2375 	 * same user or group.  Note that any group is allowed if
2376 	 * the file is owned by the caller.
2377 	 */
2378 	error = VOP_GETATTR(vp, &va);
2379 	if (error != 0)
2380 		return (error);
2381 
2382 	if (hardlink_check_uid) {
2383 		if (cred->cr_uid != va.va_uid)
2384 			return (EPERM);
2385 	}
2386 
2387 	if (hardlink_check_gid) {
2388 		if (cred->cr_uid != va.va_uid && !groupmember(va.va_gid, cred))
2389 			return (EPERM);
2390 	}
2391 
2392 	return (0);
2393 }
2394 
2395 int
2396 kern_link(struct nlookupdata *nd, struct nlookupdata *linknd)
2397 {
2398 	struct thread *td = curthread;
2399 	struct vnode *vp;
2400 	int error;
2401 
2402 	/*
2403 	 * Lookup the source and obtained a locked vnode.
2404 	 *
2405 	 * You may only hardlink a file which you have write permission
2406 	 * on or which you own.
2407 	 *
2408 	 * XXX relookup on vget failure / race ?
2409 	 */
2410 	bwillinode(1);
2411 	nd->nl_flags |= NLC_WRITE | NLC_OWN | NLC_HLINK;
2412 	if ((error = nlookup(nd)) != 0)
2413 		return (error);
2414 	vp = nd->nl_nch.ncp->nc_vp;
2415 	KKASSERT(vp != NULL);
2416 	if (vp->v_type == VDIR)
2417 		return (EPERM);		/* POSIX */
2418 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2419 		return (error);
2420 	if ((error = vget(vp, LK_EXCLUSIVE)) != 0)
2421 		return (error);
2422 
2423 	/*
2424 	 * Unlock the source so we can lookup the target without deadlocking
2425 	 * (XXX vp is locked already, possible other deadlock?).  The target
2426 	 * must not exist.
2427 	 */
2428 	KKASSERT(nd->nl_flags & NLC_NCPISLOCKED);
2429 	nd->nl_flags &= ~NLC_NCPISLOCKED;
2430 	cache_unlock(&nd->nl_nch);
2431 	vn_unlock(vp);
2432 
2433 	linknd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2434 	if ((error = nlookup(linknd)) != 0) {
2435 		vrele(vp);
2436 		return (error);
2437 	}
2438 	if (linknd->nl_nch.ncp->nc_vp) {
2439 		vrele(vp);
2440 		return (EEXIST);
2441 	}
2442 	error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_FAILRECLAIM);
2443 	if (error) {
2444 		vrele(vp);
2445 		return (error);
2446 	}
2447 
2448 	/*
2449 	 * Finally run the new API VOP.
2450 	 */
2451 	error = can_hardlink(vp, td, td->td_ucred);
2452 	if (error == 0) {
2453 		error = VOP_NLINK(&linknd->nl_nch, linknd->nl_dvp,
2454 				  vp, linknd->nl_cred);
2455 	}
2456 	vput(vp);
2457 	return (error);
2458 }
2459 
2460 /*
2461  * link_args(char *path, char *link)
2462  *
2463  * Make a hard file link.
2464  */
2465 int
2466 sys_link(struct link_args *uap)
2467 {
2468 	struct nlookupdata nd, linknd;
2469 	int error;
2470 
2471 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2472 	if (error == 0) {
2473 		error = nlookup_init(&linknd, uap->link, UIO_USERSPACE, 0);
2474 		if (error == 0)
2475 			error = kern_link(&nd, &linknd);
2476 		nlookup_done(&linknd);
2477 	}
2478 	nlookup_done(&nd);
2479 	return (error);
2480 }
2481 
2482 /*
2483  * linkat_args(int fd1, char *path1, int fd2, char *path2, int flags)
2484  *
2485  * Make a hard file link. The path1 argument is relative to the directory
2486  * associated with fd1, and similarly the path2 argument is relative to
2487  * the directory associated with fd2.
2488  */
2489 int
2490 sys_linkat(struct linkat_args *uap)
2491 {
2492 	struct nlookupdata nd, linknd;
2493 	struct file *fp1, *fp2;
2494 	int error;
2495 
2496 	error = nlookup_init_at(&nd, &fp1, uap->fd1, uap->path1, UIO_USERSPACE,
2497 	    (uap->flags & AT_SYMLINK_FOLLOW) ? NLC_FOLLOW : 0);
2498 	if (error == 0) {
2499 		error = nlookup_init_at(&linknd, &fp2, uap->fd2,
2500 		    uap->path2, UIO_USERSPACE, 0);
2501 		if (error == 0)
2502 			error = kern_link(&nd, &linknd);
2503 		nlookup_done_at(&linknd, fp2);
2504 	}
2505 	nlookup_done_at(&nd, fp1);
2506 	return (error);
2507 }
2508 
2509 int
2510 kern_symlink(struct nlookupdata *nd, char *path, int mode)
2511 {
2512 	struct vattr vattr;
2513 	struct vnode *vp;
2514 	struct vnode *dvp;
2515 	int error;
2516 
2517 	bwillinode(1);
2518 	nd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2519 	if ((error = nlookup(nd)) != 0)
2520 		return (error);
2521 	if (nd->nl_nch.ncp->nc_vp)
2522 		return (EEXIST);
2523 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2524 		return (error);
2525 	dvp = nd->nl_dvp;
2526 	VATTR_NULL(&vattr);
2527 	vattr.va_mode = mode;
2528 	error = VOP_NSYMLINK(&nd->nl_nch, dvp, &vp, nd->nl_cred, &vattr, path);
2529 	if (error == 0)
2530 		vput(vp);
2531 	return (error);
2532 }
2533 
2534 /*
2535  * symlink(char *path, char *link)
2536  *
2537  * Make a symbolic link.
2538  */
2539 int
2540 sys_symlink(struct symlink_args *uap)
2541 {
2542 	struct thread *td = curthread;
2543 	struct nlookupdata nd;
2544 	char *path;
2545 	int error;
2546 	int mode;
2547 
2548 	path = objcache_get(namei_oc, M_WAITOK);
2549 	error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
2550 	if (error == 0) {
2551 		error = nlookup_init(&nd, uap->link, UIO_USERSPACE, 0);
2552 		if (error == 0) {
2553 			mode = ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask;
2554 			error = kern_symlink(&nd, path, mode);
2555 		}
2556 		nlookup_done(&nd);
2557 	}
2558 	objcache_put(namei_oc, path);
2559 	return (error);
2560 }
2561 
2562 /*
2563  * symlinkat_args(char *path1, int fd, char *path2)
2564  *
2565  * Make a symbolic link.  The path2 argument is relative to the directory
2566  * associated with fd.
2567  */
2568 int
2569 sys_symlinkat(struct symlinkat_args *uap)
2570 {
2571 	struct thread *td = curthread;
2572 	struct nlookupdata nd;
2573 	struct file *fp;
2574 	char *path1;
2575 	int error;
2576 	int mode;
2577 
2578 	path1 = objcache_get(namei_oc, M_WAITOK);
2579 	error = copyinstr(uap->path1, path1, MAXPATHLEN, NULL);
2580 	if (error == 0) {
2581 		error = nlookup_init_at(&nd, &fp, uap->fd, uap->path2,
2582 		    UIO_USERSPACE, 0);
2583 		if (error == 0) {
2584 			mode = ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask;
2585 			error = kern_symlink(&nd, path1, mode);
2586 		}
2587 		nlookup_done_at(&nd, fp);
2588 	}
2589 	objcache_put(namei_oc, path1);
2590 	return (error);
2591 }
2592 
2593 /*
2594  * undelete_args(char *path)
2595  *
2596  * Delete a whiteout from the filesystem.
2597  */
2598 int
2599 sys_undelete(struct undelete_args *uap)
2600 {
2601 	struct nlookupdata nd;
2602 	int error;
2603 
2604 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2605 	bwillinode(1);
2606 	nd.nl_flags |= NLC_DELETE | NLC_REFDVP;
2607 	if (error == 0)
2608 		error = nlookup(&nd);
2609 	if (error == 0)
2610 		error = ncp_writechk(&nd.nl_nch);
2611 	if (error == 0) {
2612 		error = VOP_NWHITEOUT(&nd.nl_nch, nd.nl_dvp, nd.nl_cred,
2613 				      NAMEI_DELETE);
2614 	}
2615 	nlookup_done(&nd);
2616 	return (error);
2617 }
2618 
2619 int
2620 kern_unlink(struct nlookupdata *nd)
2621 {
2622 	int error;
2623 
2624 	bwillinode(1);
2625 	nd->nl_flags |= NLC_DELETE | NLC_REFDVP;
2626 	if ((error = nlookup(nd)) != 0)
2627 		return (error);
2628 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2629 		return (error);
2630 	error = VOP_NREMOVE(&nd->nl_nch, nd->nl_dvp, nd->nl_cred);
2631 	return (error);
2632 }
2633 
2634 /*
2635  * unlink_args(char *path)
2636  *
2637  * Delete a name from the filesystem.
2638  */
2639 int
2640 sys_unlink(struct unlink_args *uap)
2641 {
2642 	struct nlookupdata nd;
2643 	int error;
2644 
2645 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2646 	if (error == 0)
2647 		error = kern_unlink(&nd);
2648 	nlookup_done(&nd);
2649 	return (error);
2650 }
2651 
2652 
2653 /*
2654  * unlinkat_args(int fd, char *path, int flags)
2655  *
2656  * Delete the file or directory entry pointed to by fd/path.
2657  */
2658 int
2659 sys_unlinkat(struct unlinkat_args *uap)
2660 {
2661 	struct nlookupdata nd;
2662 	struct file *fp;
2663 	int error;
2664 
2665 	if (uap->flags & ~AT_REMOVEDIR)
2666 		return (EINVAL);
2667 
2668 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2669 	if (error == 0) {
2670 		if (uap->flags & AT_REMOVEDIR)
2671 			error = kern_rmdir(&nd);
2672 		else
2673 			error = kern_unlink(&nd);
2674 	}
2675 	nlookup_done_at(&nd, fp);
2676 	return (error);
2677 }
2678 
2679 int
2680 kern_lseek(int fd, off_t offset, int whence, off_t *res)
2681 {
2682 	struct thread *td = curthread;
2683 	struct file *fp;
2684 	struct vnode *vp;
2685 	struct vattr vattr;
2686 	off_t new_offset;
2687 	int error;
2688 
2689 	fp = holdfp(td, fd, -1);
2690 	if (fp == NULL)
2691 		return (EBADF);
2692 	if (fp->f_type != DTYPE_VNODE) {
2693 		error = ESPIPE;
2694 		goto done;
2695 	}
2696 	vp = (struct vnode *)fp->f_data;
2697 
2698 	switch (whence) {
2699 	case L_INCR:
2700 		spin_lock(&fp->f_spin);
2701 		new_offset = fp->f_offset + offset;
2702 		error = 0;
2703 		break;
2704 	case L_XTND:
2705 		error = VOP_GETATTR(vp, &vattr);
2706 		spin_lock(&fp->f_spin);
2707 		new_offset = offset + vattr.va_size;
2708 		break;
2709 	case L_SET:
2710 		new_offset = offset;
2711 		error = 0;
2712 		spin_lock(&fp->f_spin);
2713 		break;
2714 	default:
2715 		new_offset = 0;
2716 		error = EINVAL;
2717 		spin_lock(&fp->f_spin);
2718 		break;
2719 	}
2720 
2721 	/*
2722 	 * Validate the seek position.  Negative offsets are not allowed
2723 	 * for regular files or directories.
2724 	 *
2725 	 * Normally we would also not want to allow negative offsets for
2726 	 * character and block-special devices.  However kvm addresses
2727 	 * on 64 bit architectures might appear to be negative and must
2728 	 * be allowed.
2729 	 */
2730 	if (error == 0) {
2731 		if (new_offset < 0 &&
2732 		    (vp->v_type == VREG || vp->v_type == VDIR)) {
2733 			error = EINVAL;
2734 		} else {
2735 			fp->f_offset = new_offset;
2736 		}
2737 	}
2738 	*res = fp->f_offset;
2739 	spin_unlock(&fp->f_spin);
2740 done:
2741 	dropfp(td, fd, fp);
2742 
2743 	return (error);
2744 }
2745 
2746 /*
2747  * lseek_args(int fd, int pad, off_t offset, int whence)
2748  *
2749  * Reposition read/write file offset.
2750  */
2751 int
2752 sys_lseek(struct lseek_args *uap)
2753 {
2754 	int error;
2755 
2756 	error = kern_lseek(uap->fd, uap->offset, uap->whence,
2757 			   &uap->sysmsg_offset);
2758 
2759 	return (error);
2760 }
2761 
2762 /*
2763  * Check if current process can access given file.  amode is a bitmask of *_OK
2764  * access bits.  flags is a bitmask of AT_* flags.
2765  */
2766 int
2767 kern_access(struct nlookupdata *nd, int amode, int flags)
2768 {
2769 	struct vnode *vp;
2770 	int error, mode;
2771 
2772 	if (flags & ~AT_EACCESS)
2773 		return (EINVAL);
2774 	nd->nl_flags |= NLC_SHAREDLOCK;
2775 	if ((error = nlookup(nd)) != 0)
2776 		return (error);
2777 retry:
2778 	error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_SHARED, &vp);
2779 	if (error)
2780 		return (error);
2781 
2782 	/* Flags == 0 means only check for existence. */
2783 	if (amode) {
2784 		mode = 0;
2785 		if (amode & R_OK)
2786 			mode |= VREAD;
2787 		if (amode & W_OK)
2788 			mode |= VWRITE;
2789 		if (amode & X_OK)
2790 			mode |= VEXEC;
2791 		if ((mode & VWRITE) == 0 ||
2792 		    (error = vn_writechk(vp, &nd->nl_nch)) == 0)
2793 			error = VOP_ACCESS_FLAGS(vp, mode, flags, nd->nl_cred);
2794 
2795 		/*
2796 		 * If the file handle is stale we have to re-resolve the
2797 		 * entry with the ncp held exclusively.  This is a hack
2798 		 * at the moment.
2799 		 */
2800 		if (error == ESTALE) {
2801 			vput(vp);
2802 			cache_unlock(&nd->nl_nch);
2803 			cache_lock(&nd->nl_nch);
2804 			cache_setunresolved(&nd->nl_nch);
2805 			error = cache_resolve(&nd->nl_nch, nd->nl_cred);
2806 			if (error == 0) {
2807 				vp = NULL;
2808 				goto retry;
2809 			}
2810 			return(error);
2811 		}
2812 	}
2813 	vput(vp);
2814 	return (error);
2815 }
2816 
2817 /*
2818  * access_args(char *path, int flags)
2819  *
2820  * Check access permissions.
2821  */
2822 int
2823 sys_access(struct access_args *uap)
2824 {
2825 	struct nlookupdata nd;
2826 	int error;
2827 
2828 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2829 	if (error == 0)
2830 		error = kern_access(&nd, uap->flags, 0);
2831 	nlookup_done(&nd);
2832 	return (error);
2833 }
2834 
2835 
2836 /*
2837  * eaccess_args(char *path, int flags)
2838  *
2839  * Check access permissions.
2840  */
2841 int
2842 sys_eaccess(struct eaccess_args *uap)
2843 {
2844 	struct nlookupdata nd;
2845 	int error;
2846 
2847 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2848 	if (error == 0)
2849 		error = kern_access(&nd, uap->flags, AT_EACCESS);
2850 	nlookup_done(&nd);
2851 	return (error);
2852 }
2853 
2854 
2855 /*
2856  * faccessat_args(int fd, char *path, int amode, int flags)
2857  *
2858  * Check access permissions.
2859  */
2860 int
2861 sys_faccessat(struct faccessat_args *uap)
2862 {
2863 	struct nlookupdata nd;
2864 	struct file *fp;
2865 	int error;
2866 
2867 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE,
2868 				NLC_FOLLOW);
2869 	if (error == 0)
2870 		error = kern_access(&nd, uap->amode, uap->flags);
2871 	nlookup_done_at(&nd, fp);
2872 	return (error);
2873 }
2874 
2875 int
2876 kern_stat(struct nlookupdata *nd, struct stat *st)
2877 {
2878 	int error;
2879 	struct vnode *vp;
2880 
2881 	nd->nl_flags |= NLC_SHAREDLOCK;
2882 	if ((error = nlookup(nd)) != 0)
2883 		return (error);
2884 again:
2885 	if ((vp = nd->nl_nch.ncp->nc_vp) == NULL)
2886 		return (ENOENT);
2887 
2888 	if ((error = vget(vp, LK_SHARED)) != 0)
2889 		return (error);
2890 	error = vn_stat(vp, st, nd->nl_cred);
2891 
2892 	/*
2893 	 * If the file handle is stale we have to re-resolve the
2894 	 * entry with the ncp held exclusively.  This is a hack
2895 	 * at the moment.
2896 	 */
2897 	if (error == ESTALE) {
2898 		vput(vp);
2899 		cache_unlock(&nd->nl_nch);
2900 		cache_lock(&nd->nl_nch);
2901 		cache_setunresolved(&nd->nl_nch);
2902 		error = cache_resolve(&nd->nl_nch, nd->nl_cred);
2903 		if (error == 0)
2904 			goto again;
2905 	} else {
2906 		vput(vp);
2907 	}
2908 	return (error);
2909 }
2910 
2911 /*
2912  * stat_args(char *path, struct stat *ub)
2913  *
2914  * Get file status; this version follows links.
2915  */
2916 int
2917 sys_stat(struct stat_args *uap)
2918 {
2919 	struct nlookupdata nd;
2920 	struct stat st;
2921 	int error;
2922 
2923 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2924 	if (error == 0) {
2925 		error = kern_stat(&nd, &st);
2926 		if (error == 0)
2927 			error = copyout(&st, uap->ub, sizeof(*uap->ub));
2928 	}
2929 	nlookup_done(&nd);
2930 	return (error);
2931 }
2932 
2933 /*
2934  * lstat_args(char *path, struct stat *ub)
2935  *
2936  * Get file status; this version does not follow links.
2937  */
2938 int
2939 sys_lstat(struct lstat_args *uap)
2940 {
2941 	struct nlookupdata nd;
2942 	struct stat st;
2943 	int error;
2944 
2945 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2946 	if (error == 0) {
2947 		error = kern_stat(&nd, &st);
2948 		if (error == 0)
2949 			error = copyout(&st, uap->ub, sizeof(*uap->ub));
2950 	}
2951 	nlookup_done(&nd);
2952 	return (error);
2953 }
2954 
2955 /*
2956  * fstatat_args(int fd, char *path, struct stat *sb, int flags)
2957  *
2958  * Get status of file pointed to by fd/path.
2959  */
2960 int
2961 sys_fstatat(struct fstatat_args *uap)
2962 {
2963 	struct nlookupdata nd;
2964 	struct stat st;
2965 	int error;
2966 	int flags;
2967 	struct file *fp;
2968 
2969 	if (uap->flags & ~AT_SYMLINK_NOFOLLOW)
2970 		return (EINVAL);
2971 
2972 	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
2973 
2974 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path,
2975 				UIO_USERSPACE, flags);
2976 	if (error == 0) {
2977 		error = kern_stat(&nd, &st);
2978 		if (error == 0)
2979 			error = copyout(&st, uap->sb, sizeof(*uap->sb));
2980 	}
2981 	nlookup_done_at(&nd, fp);
2982 	return (error);
2983 }
2984 
2985 static int
2986 kern_pathconf(char *path, int name, int flags, register_t *sysmsg_regp)
2987 {
2988 	struct nlookupdata nd;
2989 	struct vnode *vp;
2990 	int error;
2991 
2992 	vp = NULL;
2993 	error = nlookup_init(&nd, path, UIO_USERSPACE, flags);
2994 	if (error == 0)
2995 		error = nlookup(&nd);
2996 	if (error == 0)
2997 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
2998 	nlookup_done(&nd);
2999 	if (error == 0) {
3000 		error = VOP_PATHCONF(vp, name, sysmsg_regp);
3001 		vput(vp);
3002 	}
3003 	return (error);
3004 }
3005 
3006 /*
3007  * pathconf_Args(char *path, int name)
3008  *
3009  * Get configurable pathname variables.
3010  */
3011 int
3012 sys_pathconf(struct pathconf_args *uap)
3013 {
3014 	return (kern_pathconf(uap->path, uap->name, NLC_FOLLOW,
3015 		&uap->sysmsg_reg));
3016 }
3017 
3018 /*
3019  * lpathconf_Args(char *path, int name)
3020  *
3021  * Get configurable pathname variables, but don't follow symlinks.
3022  */
3023 int
3024 sys_lpathconf(struct lpathconf_args *uap)
3025 {
3026 	return (kern_pathconf(uap->path, uap->name, 0, &uap->sysmsg_reg));
3027 }
3028 
3029 /*
3030  * XXX: daver
3031  * kern_readlink isn't properly split yet.  There is a copyin burried
3032  * in VOP_READLINK().
3033  */
3034 int
3035 kern_readlink(struct nlookupdata *nd, char *buf, int count, int *res)
3036 {
3037 	struct thread *td = curthread;
3038 	struct vnode *vp;
3039 	struct iovec aiov;
3040 	struct uio auio;
3041 	int error;
3042 
3043 	nd->nl_flags |= NLC_SHAREDLOCK;
3044 	if ((error = nlookup(nd)) != 0)
3045 		return (error);
3046 	error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_SHARED, &vp);
3047 	if (error)
3048 		return (error);
3049 	if (vp->v_type != VLNK) {
3050 		error = EINVAL;
3051 	} else {
3052 		aiov.iov_base = buf;
3053 		aiov.iov_len = count;
3054 		auio.uio_iov = &aiov;
3055 		auio.uio_iovcnt = 1;
3056 		auio.uio_offset = 0;
3057 		auio.uio_rw = UIO_READ;
3058 		auio.uio_segflg = UIO_USERSPACE;
3059 		auio.uio_td = td;
3060 		auio.uio_resid = count;
3061 		error = VOP_READLINK(vp, &auio, td->td_ucred);
3062 	}
3063 	vput(vp);
3064 	*res = count - auio.uio_resid;
3065 	return (error);
3066 }
3067 
3068 /*
3069  * readlink_args(char *path, char *buf, int count)
3070  *
3071  * Return target name of a symbolic link.
3072  */
3073 int
3074 sys_readlink(struct readlink_args *uap)
3075 {
3076 	struct nlookupdata nd;
3077 	int error;
3078 
3079 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3080 	if (error == 0) {
3081 		error = kern_readlink(&nd, uap->buf, uap->count,
3082 					&uap->sysmsg_result);
3083 	}
3084 	nlookup_done(&nd);
3085 	return (error);
3086 }
3087 
3088 /*
3089  * readlinkat_args(int fd, char *path, char *buf, size_t bufsize)
3090  *
3091  * Return target name of a symbolic link.  The path is relative to the
3092  * directory associated with fd.
3093  */
3094 int
3095 sys_readlinkat(struct readlinkat_args *uap)
3096 {
3097 	struct nlookupdata nd;
3098 	struct file *fp;
3099 	int error;
3100 
3101 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
3102 	if (error == 0) {
3103 		error = kern_readlink(&nd, uap->buf, uap->bufsize,
3104 					&uap->sysmsg_result);
3105 	}
3106 	nlookup_done_at(&nd, fp);
3107 	return (error);
3108 }
3109 
3110 static int
3111 setfflags(struct vnode *vp, int flags)
3112 {
3113 	struct thread *td = curthread;
3114 	int error;
3115 	struct vattr vattr;
3116 
3117 	/*
3118 	 * Prevent non-root users from setting flags on devices.  When
3119 	 * a device is reused, users can retain ownership of the device
3120 	 * if they are allowed to set flags and programs assume that
3121 	 * chown can't fail when done as root.
3122 	 */
3123 	if ((vp->v_type == VCHR || vp->v_type == VBLK) &&
3124 	    ((error = priv_check_cred(td->td_ucred, PRIV_VFS_CHFLAGS_DEV, 0)) != 0))
3125 		return (error);
3126 
3127 	/*
3128 	 * note: vget is required for any operation that might mod the vnode
3129 	 * so VINACTIVE is properly cleared.
3130 	 */
3131 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
3132 		VATTR_NULL(&vattr);
3133 		vattr.va_flags = flags;
3134 		error = VOP_SETATTR(vp, &vattr, td->td_ucred);
3135 		vput(vp);
3136 	}
3137 	return (error);
3138 }
3139 
3140 /*
3141  * chflags(char *path, int flags)
3142  *
3143  * Change flags of a file given a path name.
3144  */
3145 int
3146 sys_chflags(struct chflags_args *uap)
3147 {
3148 	struct nlookupdata nd;
3149 	struct vnode *vp;
3150 	int error;
3151 
3152 	vp = NULL;
3153 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3154 	if (error == 0)
3155 		error = nlookup(&nd);
3156 	if (error == 0)
3157 		error = ncp_writechk(&nd.nl_nch);
3158 	if (error == 0)
3159 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
3160 	nlookup_done(&nd);
3161 	if (error == 0) {
3162 		error = setfflags(vp, uap->flags);
3163 		vrele(vp);
3164 	}
3165 	return (error);
3166 }
3167 
3168 /*
3169  * lchflags(char *path, int flags)
3170  *
3171  * Change flags of a file given a path name, but don't follow symlinks.
3172  */
3173 int
3174 sys_lchflags(struct lchflags_args *uap)
3175 {
3176 	struct nlookupdata nd;
3177 	struct vnode *vp;
3178 	int error;
3179 
3180 	vp = NULL;
3181 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3182 	if (error == 0)
3183 		error = nlookup(&nd);
3184 	if (error == 0)
3185 		error = ncp_writechk(&nd.nl_nch);
3186 	if (error == 0)
3187 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
3188 	nlookup_done(&nd);
3189 	if (error == 0) {
3190 		error = setfflags(vp, uap->flags);
3191 		vrele(vp);
3192 	}
3193 	return (error);
3194 }
3195 
3196 /*
3197  * fchflags_args(int fd, int flags)
3198  *
3199  * Change flags of a file given a file descriptor.
3200  */
3201 int
3202 sys_fchflags(struct fchflags_args *uap)
3203 {
3204 	struct thread *td = curthread;
3205 	struct file *fp;
3206 	int error;
3207 
3208 	if ((error = holdvnode(td, uap->fd, &fp)) != 0)
3209 		return (error);
3210 	if (fp->f_nchandle.ncp)
3211 		error = ncp_writechk(&fp->f_nchandle);
3212 	if (error == 0)
3213 		error = setfflags((struct vnode *) fp->f_data, uap->flags);
3214 	fdrop(fp);
3215 	return (error);
3216 }
3217 
3218 /*
3219  * chflagsat_args(int fd, const char *path, int flags, int atflags)
3220  * change flags given a pathname relative to a filedescriptor
3221  */
3222 int sys_chflagsat(struct chflagsat_args *uap)
3223 {
3224 	struct nlookupdata nd;
3225 	struct vnode *vp;
3226 	struct file *fp;
3227 	int error;
3228 	int lookupflags;
3229 
3230 	if (uap->atflags & ~AT_SYMLINK_NOFOLLOW)
3231 		return (EINVAL);
3232 
3233 	lookupflags = (uap->atflags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
3234 
3235 	vp = NULL;
3236 	error = nlookup_init_at(&nd, &fp, uap->fd,  uap->path, UIO_USERSPACE, lookupflags);
3237 	if (error == 0)
3238 		error = nlookup(&nd);
3239 	if (error == 0)
3240 		error = ncp_writechk(&nd.nl_nch);
3241 	if (error == 0)
3242 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
3243 	nlookup_done_at(&nd, fp);
3244 	if (error == 0) {
3245 		error = setfflags(vp, uap->flags);
3246 		vrele(vp);
3247 	}
3248 	return (error);
3249 }
3250 
3251 
3252 static int
3253 setfmode(struct vnode *vp, int mode)
3254 {
3255 	struct thread *td = curthread;
3256 	int error;
3257 	struct vattr vattr;
3258 
3259 	/*
3260 	 * note: vget is required for any operation that might mod the vnode
3261 	 * so VINACTIVE is properly cleared.
3262 	 */
3263 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
3264 		VATTR_NULL(&vattr);
3265 		vattr.va_mode = mode & ALLPERMS;
3266 		error = VOP_SETATTR(vp, &vattr, td->td_ucred);
3267 		cache_inval_wxok(vp);
3268 		vput(vp);
3269 	}
3270 	return error;
3271 }
3272 
3273 int
3274 kern_chmod(struct nlookupdata *nd, int mode)
3275 {
3276 	struct vnode *vp;
3277 	int error;
3278 
3279 	if ((error = nlookup(nd)) != 0)
3280 		return (error);
3281 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
3282 		return (error);
3283 	if ((error = ncp_writechk(&nd->nl_nch)) == 0)
3284 		error = setfmode(vp, mode);
3285 	vrele(vp);
3286 	return (error);
3287 }
3288 
3289 /*
3290  * chmod_args(char *path, int mode)
3291  *
3292  * Change mode of a file given path name.
3293  */
3294 int
3295 sys_chmod(struct chmod_args *uap)
3296 {
3297 	struct nlookupdata nd;
3298 	int error;
3299 
3300 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3301 	if (error == 0)
3302 		error = kern_chmod(&nd, uap->mode);
3303 	nlookup_done(&nd);
3304 	return (error);
3305 }
3306 
3307 /*
3308  * lchmod_args(char *path, int mode)
3309  *
3310  * Change mode of a file given path name (don't follow links.)
3311  */
3312 int
3313 sys_lchmod(struct lchmod_args *uap)
3314 {
3315 	struct nlookupdata nd;
3316 	int error;
3317 
3318 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3319 	if (error == 0)
3320 		error = kern_chmod(&nd, uap->mode);
3321 	nlookup_done(&nd);
3322 	return (error);
3323 }
3324 
3325 /*
3326  * fchmod_args(int fd, int mode)
3327  *
3328  * Change mode of a file given a file descriptor.
3329  */
3330 int
3331 sys_fchmod(struct fchmod_args *uap)
3332 {
3333 	struct thread *td = curthread;
3334 	struct file *fp;
3335 	int error;
3336 
3337 	if ((error = holdvnode(td, uap->fd, &fp)) != 0)
3338 		return (error);
3339 	if (fp->f_nchandle.ncp)
3340 		error = ncp_writechk(&fp->f_nchandle);
3341 	if (error == 0)
3342 		error = setfmode((struct vnode *)fp->f_data, uap->mode);
3343 	fdrop(fp);
3344 	return (error);
3345 }
3346 
3347 /*
3348  * fchmodat_args(char *path, int mode)
3349  *
3350  * Change mode of a file pointed to by fd/path.
3351  */
3352 int
3353 sys_fchmodat(struct fchmodat_args *uap)
3354 {
3355 	struct nlookupdata nd;
3356 	struct file *fp;
3357 	int error;
3358 	int flags;
3359 
3360 	if (uap->flags & ~AT_SYMLINK_NOFOLLOW)
3361 		return (EINVAL);
3362 	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
3363 
3364 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path,
3365 				UIO_USERSPACE, flags);
3366 	if (error == 0)
3367 		error = kern_chmod(&nd, uap->mode);
3368 	nlookup_done_at(&nd, fp);
3369 	return (error);
3370 }
3371 
3372 static int
3373 setfown(struct mount *mp, struct vnode *vp, uid_t uid, gid_t gid)
3374 {
3375 	struct thread *td = curthread;
3376 	int error;
3377 	struct vattr vattr;
3378 	uid_t o_uid;
3379 	gid_t o_gid;
3380 	uint64_t size;
3381 
3382 	/*
3383 	 * note: vget is required for any operation that might mod the vnode
3384 	 * so VINACTIVE is properly cleared.
3385 	 */
3386 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
3387 		if ((error = VOP_GETATTR(vp, &vattr)) != 0)
3388 			return error;
3389 		o_uid = vattr.va_uid;
3390 		o_gid = vattr.va_gid;
3391 		size = vattr.va_size;
3392 
3393 		VATTR_NULL(&vattr);
3394 		vattr.va_uid = uid;
3395 		vattr.va_gid = gid;
3396 		error = VOP_SETATTR(vp, &vattr, td->td_ucred);
3397 		vput(vp);
3398 	}
3399 
3400 	if (error == 0) {
3401 		if (uid == -1)
3402 			uid = o_uid;
3403 		if (gid == -1)
3404 			gid = o_gid;
3405 		VFS_ACCOUNT(mp, o_uid, o_gid, -size);
3406 		VFS_ACCOUNT(mp,   uid,   gid,  size);
3407 	}
3408 
3409 	return error;
3410 }
3411 
3412 int
3413 kern_chown(struct nlookupdata *nd, int uid, int gid)
3414 {
3415 	struct vnode *vp;
3416 	int error;
3417 
3418 	if ((error = nlookup(nd)) != 0)
3419 		return (error);
3420 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
3421 		return (error);
3422 	if ((error = ncp_writechk(&nd->nl_nch)) == 0)
3423 		error = setfown(nd->nl_nch.mount, vp, uid, gid);
3424 	vrele(vp);
3425 	return (error);
3426 }
3427 
3428 /*
3429  * chown(char *path, int uid, int gid)
3430  *
3431  * Set ownership given a path name.
3432  */
3433 int
3434 sys_chown(struct chown_args *uap)
3435 {
3436 	struct nlookupdata nd;
3437 	int error;
3438 
3439 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3440 	if (error == 0)
3441 		error = kern_chown(&nd, uap->uid, uap->gid);
3442 	nlookup_done(&nd);
3443 	return (error);
3444 }
3445 
3446 /*
3447  * lchown_args(char *path, int uid, int gid)
3448  *
3449  * Set ownership given a path name, do not cross symlinks.
3450  */
3451 int
3452 sys_lchown(struct lchown_args *uap)
3453 {
3454 	struct nlookupdata nd;
3455 	int error;
3456 
3457 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3458 	if (error == 0)
3459 		error = kern_chown(&nd, uap->uid, uap->gid);
3460 	nlookup_done(&nd);
3461 	return (error);
3462 }
3463 
3464 /*
3465  * fchown_args(int fd, int uid, int gid)
3466  *
3467  * Set ownership given a file descriptor.
3468  */
3469 int
3470 sys_fchown(struct fchown_args *uap)
3471 {
3472 	struct thread *td = curthread;
3473 	struct proc *p = td->td_proc;
3474 	struct file *fp;
3475 	int error;
3476 
3477 	if ((error = holdvnode(td, uap->fd, &fp)) != 0)
3478 		return (error);
3479 	if (fp->f_nchandle.ncp)
3480 		error = ncp_writechk(&fp->f_nchandle);
3481 	if (error == 0)
3482 		error = setfown(p->p_fd->fd_ncdir.mount,
3483 			(struct vnode *)fp->f_data, uap->uid, uap->gid);
3484 	fdrop(fp);
3485 	return (error);
3486 }
3487 
3488 /*
3489  * fchownat(int fd, char *path, int uid, int gid, int flags)
3490  *
3491  * Set ownership of file pointed to by fd/path.
3492  */
3493 int
3494 sys_fchownat(struct fchownat_args *uap)
3495 {
3496 	struct nlookupdata nd;
3497 	struct file *fp;
3498 	int error;
3499 	int flags;
3500 
3501 	if (uap->flags & ~AT_SYMLINK_NOFOLLOW)
3502 		return (EINVAL);
3503 	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
3504 
3505 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path,
3506 				UIO_USERSPACE, flags);
3507 	if (error == 0)
3508 		error = kern_chown(&nd, uap->uid, uap->gid);
3509 	nlookup_done_at(&nd, fp);
3510 	return (error);
3511 }
3512 
3513 
3514 static int
3515 getutimes(struct timeval *tvp, struct timespec *tsp)
3516 {
3517 	struct timeval tv[2];
3518 	int error;
3519 
3520 	if (tvp == NULL) {
3521 		microtime(&tv[0]);
3522 		TIMEVAL_TO_TIMESPEC(&tv[0], &tsp[0]);
3523 		tsp[1] = tsp[0];
3524 	} else {
3525 		if ((error = itimerfix(tvp)) != 0)
3526 			return (error);
3527 		TIMEVAL_TO_TIMESPEC(&tvp[0], &tsp[0]);
3528 		TIMEVAL_TO_TIMESPEC(&tvp[1], &tsp[1]);
3529 	}
3530 	return 0;
3531 }
3532 
3533 static int
3534 getutimens(const struct timespec *ts, struct timespec *newts, int *nullflag)
3535 {
3536 	struct timespec tsnow;
3537 	int error;
3538 
3539 	*nullflag = 0;
3540 	nanotime(&tsnow);
3541 	if (ts == NULL) {
3542 		newts[0] = tsnow;
3543 		newts[1] = tsnow;
3544 		*nullflag = 1;
3545 		return (0);
3546 	}
3547 
3548 	newts[0] = ts[0];
3549 	newts[1] = ts[1];
3550 	if (newts[0].tv_nsec == UTIME_OMIT && newts[1].tv_nsec == UTIME_OMIT)
3551 		return (0);
3552 	if (newts[0].tv_nsec == UTIME_NOW && newts[1].tv_nsec == UTIME_NOW)
3553 		*nullflag = 1;
3554 
3555 	if (newts[0].tv_nsec == UTIME_OMIT)
3556 		newts[0].tv_sec = VNOVAL;
3557 	else if (newts[0].tv_nsec == UTIME_NOW)
3558 		newts[0] = tsnow;
3559 	else if ((error = itimespecfix(&newts[0])) != 0)
3560 		return (error);
3561 
3562 	if (newts[1].tv_nsec == UTIME_OMIT)
3563 		newts[1].tv_sec = VNOVAL;
3564 	else if (newts[1].tv_nsec == UTIME_NOW)
3565 		newts[1] = tsnow;
3566 	else if ((error = itimespecfix(&newts[1])) != 0)
3567 		return (error);
3568 
3569 	return (0);
3570 }
3571 
3572 static int
3573 setutimes(struct vnode *vp, struct vattr *vattr,
3574 	  const struct timespec *ts, int nullflag)
3575 {
3576 	struct thread *td = curthread;
3577 	int error;
3578 
3579 	VATTR_NULL(vattr);
3580 	vattr->va_atime = ts[0];
3581 	vattr->va_mtime = ts[1];
3582 	if (nullflag)
3583 		vattr->va_vaflags |= VA_UTIMES_NULL;
3584 	error = VOP_SETATTR(vp, vattr, td->td_ucred);
3585 
3586 	return error;
3587 }
3588 
3589 int
3590 kern_utimes(struct nlookupdata *nd, struct timeval *tptr)
3591 {
3592 	struct timespec ts[2];
3593 	int error;
3594 
3595 	if (tptr) {
3596 		if ((error = getutimes(tptr, ts)) != 0)
3597 			return (error);
3598 	}
3599 	error = kern_utimensat(nd, tptr ? ts : NULL, 0);
3600 	return (error);
3601 }
3602 
3603 /*
3604  * utimes_args(char *path, struct timeval *tptr)
3605  *
3606  * Set the access and modification times of a file.
3607  */
3608 int
3609 sys_utimes(struct utimes_args *uap)
3610 {
3611 	struct timeval tv[2];
3612 	struct nlookupdata nd;
3613 	int error;
3614 
3615 	if (uap->tptr) {
3616  		error = copyin(uap->tptr, tv, sizeof(tv));
3617 		if (error)
3618 			return (error);
3619 	}
3620 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3621 	if (error == 0)
3622 		error = kern_utimes(&nd, uap->tptr ? tv : NULL);
3623 	nlookup_done(&nd);
3624 	return (error);
3625 }
3626 
3627 /*
3628  * lutimes_args(char *path, struct timeval *tptr)
3629  *
3630  * Set the access and modification times of a file.
3631  */
3632 int
3633 sys_lutimes(struct lutimes_args *uap)
3634 {
3635 	struct timeval tv[2];
3636 	struct nlookupdata nd;
3637 	int error;
3638 
3639 	if (uap->tptr) {
3640 		error = copyin(uap->tptr, tv, sizeof(tv));
3641 		if (error)
3642 			return (error);
3643 	}
3644 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3645 	if (error == 0)
3646 		error = kern_utimes(&nd, uap->tptr ? tv : NULL);
3647 	nlookup_done(&nd);
3648 	return (error);
3649 }
3650 
3651 /*
3652  * Set utimes on a file descriptor.  The creds used to open the
3653  * file are used to determine whether the operation is allowed
3654  * or not.
3655  */
3656 int
3657 kern_futimens(int fd, struct timespec *ts)
3658 {
3659 	struct thread *td = curthread;
3660 	struct timespec newts[2];
3661 	struct file *fp;
3662 	struct vnode *vp;
3663 	struct vattr vattr;
3664 	int nullflag;
3665 	int error;
3666 
3667 	error = getutimens(ts, newts, &nullflag);
3668 	if (error)
3669 		return (error);
3670 	if ((error = holdvnode(td, fd, &fp)) != 0)
3671 		return (error);
3672 	if (fp->f_nchandle.ncp)
3673 		error = ncp_writechk(&fp->f_nchandle);
3674 	if (error == 0) {
3675 		vp = fp->f_data;
3676 		error = vget(vp, LK_EXCLUSIVE);
3677 		if (error == 0) {
3678 			error = VOP_GETATTR(vp, &vattr);
3679 			if (error == 0) {
3680 				error = naccess_va(&vattr, NLC_OWN | NLC_WRITE,
3681 						   fp->f_cred);
3682 			}
3683 			if (error == 0) {
3684 				error = setutimes(vp, &vattr, newts, nullflag);
3685 			}
3686 			vput(vp);
3687 		}
3688 	}
3689 	fdrop(fp);
3690 	return (error);
3691 }
3692 
3693 /*
3694  * futimens_args(int fd, struct timespec *ts)
3695  *
3696  * Set the access and modification times of a file.
3697  */
3698 int
3699 sys_futimens(struct futimens_args *uap)
3700 {
3701 	struct timespec ts[2];
3702 	int error;
3703 
3704 	if (uap->ts) {
3705 		error = copyin(uap->ts, ts, sizeof(ts));
3706 		if (error)
3707 			return (error);
3708 	}
3709 	error = kern_futimens(uap->fd, uap->ts ? ts : NULL);
3710 	return (error);
3711 }
3712 
3713 int
3714 kern_futimes(int fd, struct timeval *tptr)
3715 {
3716 	struct timespec ts[2];
3717 	int error;
3718 
3719 	if (tptr) {
3720 		if ((error = getutimes(tptr, ts)) != 0)
3721 			return (error);
3722 	}
3723 	error = kern_futimens(fd, tptr ? ts : NULL);
3724 	return (error);
3725 }
3726 
3727 /*
3728  * futimes_args(int fd, struct timeval *tptr)
3729  *
3730  * Set the access and modification times of a file.
3731  */
3732 int
3733 sys_futimes(struct futimes_args *uap)
3734 {
3735 	struct timeval tv[2];
3736 	int error;
3737 
3738 	if (uap->tptr) {
3739 		error = copyin(uap->tptr, tv, sizeof(tv));
3740 		if (error)
3741 			return (error);
3742 	}
3743 	error = kern_futimes(uap->fd, uap->tptr ? tv : NULL);
3744 	return (error);
3745 }
3746 
3747 int
3748 kern_utimensat(struct nlookupdata *nd, const struct timespec *ts, int flags)
3749 {
3750 	struct timespec newts[2];
3751 	struct vnode *vp;
3752 	struct vattr vattr;
3753 	int nullflag;
3754 	int error;
3755 
3756 	if (flags & ~AT_SYMLINK_NOFOLLOW)
3757 		return (EINVAL);
3758 
3759 	error = getutimens(ts, newts, &nullflag);
3760 	if (error)
3761 		return (error);
3762 
3763 	nd->nl_flags |= NLC_OWN | NLC_WRITE;
3764 	if ((error = nlookup(nd)) != 0)
3765 		return (error);
3766 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3767 		return (error);
3768 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
3769 		return (error);
3770 	if ((error = vn_writechk(vp, &nd->nl_nch)) == 0) {
3771 		error = vget(vp, LK_EXCLUSIVE);
3772 		if (error == 0) {
3773 			error = setutimes(vp, &vattr, newts, nullflag);
3774 			vput(vp);
3775 		}
3776 	}
3777 	vrele(vp);
3778 	return (error);
3779 }
3780 
3781 /*
3782  * utimensat_args(int fd, const char *path, const struct timespec *ts, int flags);
3783  *
3784  * Set file access and modification times of a file.
3785  */
3786 int
3787 sys_utimensat(struct utimensat_args *uap)
3788 {
3789 	struct timespec ts[2];
3790 	struct nlookupdata nd;
3791 	struct file *fp;
3792 	int error;
3793 	int flags;
3794 
3795 	if (uap->ts) {
3796 		error = copyin(uap->ts, ts, sizeof(ts));
3797 		if (error)
3798 			return (error);
3799 	}
3800 
3801 	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
3802 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path,
3803 	                        UIO_USERSPACE, flags);
3804 	if (error == 0)
3805 		error = kern_utimensat(&nd, uap->ts ? ts : NULL, uap->flags);
3806 	nlookup_done_at(&nd, fp);
3807 	return (error);
3808 }
3809 
3810 int
3811 kern_truncate(struct nlookupdata *nd, off_t length)
3812 {
3813 	struct vnode *vp;
3814 	struct vattr vattr;
3815 	int error;
3816 	uid_t uid = 0;
3817 	gid_t gid = 0;
3818 	uint64_t old_size = 0;
3819 
3820 	if (length < 0)
3821 		return(EINVAL);
3822 	nd->nl_flags |= NLC_WRITE | NLC_TRUNCATE;
3823 	if ((error = nlookup(nd)) != 0)
3824 		return (error);
3825 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3826 		return (error);
3827 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
3828 		return (error);
3829 	error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_FAILRECLAIM);
3830 	if (error) {
3831 		vrele(vp);
3832 		return (error);
3833 	}
3834 	if (vp->v_type == VDIR) {
3835 		error = EISDIR;
3836 		goto done;
3837 	}
3838 	if (vfs_quota_enabled) {
3839 		error = VOP_GETATTR(vp, &vattr);
3840 		KASSERT(error == 0, ("kern_truncate(): VOP_GETATTR didn't return 0"));
3841 		uid = vattr.va_uid;
3842 		gid = vattr.va_gid;
3843 		old_size = vattr.va_size;
3844 	}
3845 
3846 	if ((error = vn_writechk(vp, &nd->nl_nch)) == 0) {
3847 		VATTR_NULL(&vattr);
3848 		vattr.va_size = length;
3849 		error = VOP_SETATTR(vp, &vattr, nd->nl_cred);
3850 		VFS_ACCOUNT(nd->nl_nch.mount, uid, gid, length - old_size);
3851 	}
3852 done:
3853 	vput(vp);
3854 	return (error);
3855 }
3856 
3857 /*
3858  * truncate(char *path, int pad, off_t length)
3859  *
3860  * Truncate a file given its path name.
3861  */
3862 int
3863 sys_truncate(struct truncate_args *uap)
3864 {
3865 	struct nlookupdata nd;
3866 	int error;
3867 
3868 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3869 	if (error == 0)
3870 		error = kern_truncate(&nd, uap->length);
3871 	nlookup_done(&nd);
3872 	return error;
3873 }
3874 
3875 int
3876 kern_ftruncate(int fd, off_t length)
3877 {
3878 	struct thread *td = curthread;
3879 	struct vattr vattr;
3880 	struct vnode *vp;
3881 	struct file *fp;
3882 	int error;
3883 	uid_t uid = 0;
3884 	gid_t gid = 0;
3885 	uint64_t old_size = 0;
3886 	struct mount *mp;
3887 
3888 	if (length < 0)
3889 		return(EINVAL);
3890 	if ((error = holdvnode(td, fd, &fp)) != 0)
3891 		return (error);
3892 	if (fp->f_nchandle.ncp) {
3893 		error = ncp_writechk(&fp->f_nchandle);
3894 		if (error)
3895 			goto done;
3896 	}
3897 	if ((fp->f_flag & FWRITE) == 0) {
3898 		error = EINVAL;
3899 		goto done;
3900 	}
3901 	if (fp->f_flag & FAPPENDONLY) {	/* inode was set s/uapnd */
3902 		error = EINVAL;
3903 		goto done;
3904 	}
3905 	vp = (struct vnode *)fp->f_data;
3906 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3907 	if (vp->v_type == VDIR) {
3908 		error = EISDIR;
3909 		vn_unlock(vp);
3910 		goto done;
3911 	}
3912 
3913 	if (vfs_quota_enabled) {
3914 		error = VOP_GETATTR(vp, &vattr);
3915 		KASSERT(error == 0, ("kern_ftruncate(): VOP_GETATTR didn't return 0"));
3916 		uid = vattr.va_uid;
3917 		gid = vattr.va_gid;
3918 		old_size = vattr.va_size;
3919 	}
3920 
3921 	if ((error = vn_writechk(vp, NULL)) == 0) {
3922 		VATTR_NULL(&vattr);
3923 		vattr.va_size = length;
3924 		error = VOP_SETATTR(vp, &vattr, fp->f_cred);
3925 		mp = vq_vptomp(vp);
3926 		VFS_ACCOUNT(mp, uid, gid, length - old_size);
3927 	}
3928 	vn_unlock(vp);
3929 done:
3930 	fdrop(fp);
3931 	return (error);
3932 }
3933 
3934 /*
3935  * ftruncate_args(int fd, int pad, off_t length)
3936  *
3937  * Truncate a file given a file descriptor.
3938  */
3939 int
3940 sys_ftruncate(struct ftruncate_args *uap)
3941 {
3942 	int error;
3943 
3944 	error = kern_ftruncate(uap->fd, uap->length);
3945 
3946 	return (error);
3947 }
3948 
3949 /*
3950  * fsync(int fd)
3951  *
3952  * Sync an open file.
3953  */
3954 int
3955 sys_fsync(struct fsync_args *uap)
3956 {
3957 	struct thread *td = curthread;
3958 	struct vnode *vp;
3959 	struct file *fp;
3960 	vm_object_t obj;
3961 	int error;
3962 
3963 	if ((error = holdvnode(td, uap->fd, &fp)) != 0)
3964 		return (error);
3965 	vp = (struct vnode *)fp->f_data;
3966 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3967 	if ((obj = vp->v_object) != NULL) {
3968 		if (vp->v_mount == NULL ||
3969 		    (vp->v_mount->mnt_kern_flag & MNTK_NOMSYNC) == 0) {
3970 			vm_object_page_clean(obj, 0, 0, 0);
3971 		}
3972 	}
3973 	error = VOP_FSYNC(vp, MNT_WAIT, VOP_FSYNC_SYSCALL);
3974 	if (error == 0 && vp->v_mount)
3975 		error = buf_fsync(vp);
3976 	vn_unlock(vp);
3977 	fdrop(fp);
3978 
3979 	return (error);
3980 }
3981 
3982 int
3983 kern_rename(struct nlookupdata *fromnd, struct nlookupdata *tond)
3984 {
3985 	struct nchandle fnchd;
3986 	struct nchandle tnchd;
3987 	struct namecache *ncp;
3988 	struct vnode *fdvp;
3989 	struct vnode *tdvp;
3990 	struct mount *mp;
3991 	int error;
3992 	u_int fncp_gen;
3993 	u_int tncp_gen;
3994 
3995 	bwillinode(1);
3996 	fromnd->nl_flags |= NLC_REFDVP | NLC_RENAME_SRC;
3997 	if ((error = nlookup(fromnd)) != 0)
3998 		return (error);
3999 	if ((fnchd.ncp = fromnd->nl_nch.ncp->nc_parent) == NULL)
4000 		return (ENOENT);
4001 	fnchd.mount = fromnd->nl_nch.mount;
4002 	cache_hold(&fnchd);
4003 
4004 	/*
4005 	 * unlock the source nch so we can lookup the target nch without
4006 	 * deadlocking.  The target may or may not exist so we do not check
4007 	 * for a target vp like kern_mkdir() and other creation functions do.
4008 	 *
4009 	 * The source and target directories are ref'd and rechecked after
4010 	 * everything is relocked to determine if the source or target file
4011 	 * has been renamed.
4012 	 */
4013 	KKASSERT(fromnd->nl_flags & NLC_NCPISLOCKED);
4014 	fromnd->nl_flags &= ~NLC_NCPISLOCKED;
4015 
4016 	fncp_gen = fromnd->nl_nch.ncp->nc_generation;
4017 
4018 	cache_unlock(&fromnd->nl_nch);
4019 
4020 	tond->nl_flags |= NLC_RENAME_DST | NLC_REFDVP;
4021 	if ((error = nlookup(tond)) != 0) {
4022 		cache_drop(&fnchd);
4023 		return (error);
4024 	}
4025 	tncp_gen = tond->nl_nch.ncp->nc_generation;
4026 
4027 	if ((tnchd.ncp = tond->nl_nch.ncp->nc_parent) == NULL) {
4028 		cache_drop(&fnchd);
4029 		return (ENOENT);
4030 	}
4031 	tnchd.mount = tond->nl_nch.mount;
4032 	cache_hold(&tnchd);
4033 
4034 	/*
4035 	 * If the source and target are the same there is nothing to do
4036 	 */
4037 	if (fromnd->nl_nch.ncp == tond->nl_nch.ncp) {
4038 		cache_drop(&fnchd);
4039 		cache_drop(&tnchd);
4040 		return (0);
4041 	}
4042 
4043 	/*
4044 	 * Mount points cannot be renamed or overwritten
4045 	 */
4046 	if ((fromnd->nl_nch.ncp->nc_flag | tond->nl_nch.ncp->nc_flag) &
4047 	    NCF_ISMOUNTPT
4048 	) {
4049 		cache_drop(&fnchd);
4050 		cache_drop(&tnchd);
4051 		return (EINVAL);
4052 	}
4053 
4054 	/*
4055 	 * Relock the source ncp.  cache_relock() will deal with any
4056 	 * deadlocks against the already-locked tond and will also
4057 	 * make sure both are resolved.
4058 	 *
4059 	 * NOTE AFTER RELOCKING: The source or target ncp may have become
4060 	 * invalid while they were unlocked, nc_vp and nc_mount could
4061 	 * be NULL.
4062 	 */
4063 	cache_relock(&fromnd->nl_nch, fromnd->nl_cred,
4064 		     &tond->nl_nch, tond->nl_cred);
4065 	fromnd->nl_flags |= NLC_NCPISLOCKED;
4066 
4067 	/*
4068 	 * If the namecache generation changed for either fromnd or tond,
4069 	 * we must retry.
4070 	 */
4071 	if (fromnd->nl_nch.ncp->nc_generation != fncp_gen ||
4072 	    tond->nl_nch.ncp->nc_generation != tncp_gen) {
4073 		kprintf("kern_rename: retry due to gen on: "
4074 			"\"%s\" -> \"%s\"\n",
4075 			fromnd->nl_nch.ncp->nc_name,
4076 			tond->nl_nch.ncp->nc_name);
4077 		cache_drop(&fnchd);
4078 		cache_drop(&tnchd);
4079 		return (EAGAIN);
4080 	}
4081 
4082 	/*
4083 	 * If either fromnd or tond are marked destroyed a ripout occured
4084 	 * out from under us and we must retry.
4085 	 */
4086 	if ((fromnd->nl_nch.ncp->nc_flag & (NCF_DESTROYED | NCF_UNRESOLVED)) ||
4087 	    fromnd->nl_nch.ncp->nc_vp == NULL ||
4088 	    (tond->nl_nch.ncp->nc_flag & NCF_DESTROYED)) {
4089 		kprintf("kern_rename: retry due to ripout on: "
4090 			"\"%s\" -> \"%s\"\n",
4091 			fromnd->nl_nch.ncp->nc_name,
4092 			tond->nl_nch.ncp->nc_name);
4093 		cache_drop(&fnchd);
4094 		cache_drop(&tnchd);
4095 		return (EAGAIN);
4096 	}
4097 
4098 	/*
4099 	 * Make sure the parent directories linkages are the same.
4100 	 * XXX shouldn't be needed any more w/ generation check above.
4101 	 */
4102 	if (fnchd.ncp != fromnd->nl_nch.ncp->nc_parent ||
4103 	    tnchd.ncp != tond->nl_nch.ncp->nc_parent) {
4104 		cache_drop(&fnchd);
4105 		cache_drop(&tnchd);
4106 		return (ENOENT);
4107 	}
4108 
4109 	/*
4110 	 * Both the source and target must be within the same filesystem and
4111 	 * in the same filesystem as their parent directories within the
4112 	 * namecache topology.
4113 	 *
4114 	 * NOTE: fromnd's nc_mount or nc_vp could be NULL.
4115 	 */
4116 	mp = fnchd.mount;
4117 	if (mp != tnchd.mount || mp != fromnd->nl_nch.mount ||
4118 	    mp != tond->nl_nch.mount) {
4119 		cache_drop(&fnchd);
4120 		cache_drop(&tnchd);
4121 		return (EXDEV);
4122 	}
4123 
4124 	/*
4125 	 * Make sure the mount point is writable
4126 	 */
4127 	if ((error = ncp_writechk(&tond->nl_nch)) != 0) {
4128 		cache_drop(&fnchd);
4129 		cache_drop(&tnchd);
4130 		return (error);
4131 	}
4132 
4133 	/*
4134 	 * If the target exists and either the source or target is a directory,
4135 	 * then both must be directories.
4136 	 *
4137 	 * Due to relocking of the source, fromnd->nl_nch.ncp->nc_vp might h
4138 	 * have become NULL.
4139 	 */
4140 	if (tond->nl_nch.ncp->nc_vp) {
4141 		if (fromnd->nl_nch.ncp->nc_vp == NULL) {
4142 			error = ENOENT;
4143 		} else if (fromnd->nl_nch.ncp->nc_vp->v_type == VDIR) {
4144 			if (tond->nl_nch.ncp->nc_vp->v_type != VDIR)
4145 				error = ENOTDIR;
4146 		} else if (tond->nl_nch.ncp->nc_vp->v_type == VDIR) {
4147 			error = EISDIR;
4148 		}
4149 	}
4150 
4151 	/*
4152 	 * You cannot rename a source into itself or a subdirectory of itself.
4153 	 * We check this by travsersing the target directory upwards looking
4154 	 * for a match against the source.
4155 	 *
4156 	 * XXX MPSAFE
4157 	 */
4158 	if (error == 0) {
4159 		for (ncp = tnchd.ncp; ncp; ncp = ncp->nc_parent) {
4160 			if (fromnd->nl_nch.ncp == ncp) {
4161 				error = EINVAL;
4162 				break;
4163 			}
4164 		}
4165 	}
4166 
4167 	cache_drop(&fnchd);
4168 	cache_drop(&tnchd);
4169 
4170 	/*
4171 	 * Even though the namespaces are different, they may still represent
4172 	 * hardlinks to the same file.  The filesystem might have a hard time
4173 	 * with this so we issue a NREMOVE of the source instead of a NRENAME
4174 	 * when we detect the situation.
4175 	 */
4176 	if (error == 0) {
4177 		fdvp = fromnd->nl_dvp;
4178 		tdvp = tond->nl_dvp;
4179 		if (fdvp == NULL || tdvp == NULL) {
4180 			error = EPERM;
4181 		} else if (fromnd->nl_nch.ncp->nc_vp == tond->nl_nch.ncp->nc_vp) {
4182 			error = VOP_NREMOVE(&fromnd->nl_nch, fdvp,
4183 					    fromnd->nl_cred);
4184 		} else {
4185 			error = VOP_NRENAME(&fromnd->nl_nch, &tond->nl_nch,
4186 					    fdvp, tdvp, tond->nl_cred);
4187 		}
4188 	}
4189 	return (error);
4190 }
4191 
4192 /*
4193  * rename_args(char *from, char *to)
4194  *
4195  * Rename files.  Source and destination must either both be directories,
4196  * or both not be directories.  If target is a directory, it must be empty.
4197  */
4198 int
4199 sys_rename(struct rename_args *uap)
4200 {
4201 	struct nlookupdata fromnd, tond;
4202 	int error;
4203 
4204 	do {
4205 		error = nlookup_init(&fromnd, uap->from, UIO_USERSPACE, 0);
4206 		if (error == 0) {
4207 			error = nlookup_init(&tond, uap->to, UIO_USERSPACE, 0);
4208 			if (error == 0)
4209 				error = kern_rename(&fromnd, &tond);
4210 			nlookup_done(&tond);
4211 		}
4212 		nlookup_done(&fromnd);
4213 	} while (error == EAGAIN);
4214 	return (error);
4215 }
4216 
4217 /*
4218  * renameat_args(int oldfd, char *old, int newfd, char *new)
4219  *
4220  * Rename files using paths relative to the directories associated with
4221  * oldfd and newfd.  Source and destination must either both be directories,
4222  * or both not be directories.  If target is a directory, it must be empty.
4223  */
4224 int
4225 sys_renameat(struct renameat_args *uap)
4226 {
4227 	struct nlookupdata oldnd, newnd;
4228 	struct file *oldfp, *newfp;
4229 	int error;
4230 
4231 	do {
4232 		error = nlookup_init_at(&oldnd, &oldfp,
4233 					uap->oldfd, uap->old,
4234 					UIO_USERSPACE, 0);
4235 		if (error == 0) {
4236 			error = nlookup_init_at(&newnd, &newfp,
4237 						uap->newfd, uap->new,
4238 						UIO_USERSPACE, 0);
4239 			if (error == 0)
4240 				error = kern_rename(&oldnd, &newnd);
4241 			nlookup_done_at(&newnd, newfp);
4242 		}
4243 		nlookup_done_at(&oldnd, oldfp);
4244 	} while (error == EAGAIN);
4245 	return (error);
4246 }
4247 
4248 int
4249 kern_mkdir(struct nlookupdata *nd, int mode)
4250 {
4251 	struct thread *td = curthread;
4252 	struct proc *p = td->td_proc;
4253 	struct vnode *vp;
4254 	struct vattr vattr;
4255 	int error;
4256 
4257 	bwillinode(1);
4258 	nd->nl_flags |= NLC_WILLBEDIR | NLC_CREATE | NLC_REFDVP;
4259 	if ((error = nlookup(nd)) != 0)
4260 		return (error);
4261 
4262 	if (nd->nl_nch.ncp->nc_vp)
4263 		return (EEXIST);
4264 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
4265 		return (error);
4266 	VATTR_NULL(&vattr);
4267 	vattr.va_type = VDIR;
4268 	vattr.va_mode = (mode & ACCESSPERMS) &~ p->p_fd->fd_cmask;
4269 
4270 	vp = NULL;
4271 	error = VOP_NMKDIR(&nd->nl_nch, nd->nl_dvp, &vp, td->td_ucred, &vattr);
4272 	if (error == 0)
4273 		vput(vp);
4274 	return (error);
4275 }
4276 
4277 /*
4278  * mkdir_args(char *path, int mode)
4279  *
4280  * Make a directory file.
4281  */
4282 int
4283 sys_mkdir(struct mkdir_args *uap)
4284 {
4285 	struct nlookupdata nd;
4286 	int error;
4287 
4288 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
4289 	if (error == 0)
4290 		error = kern_mkdir(&nd, uap->mode);
4291 	nlookup_done(&nd);
4292 	return (error);
4293 }
4294 
4295 /*
4296  * mkdirat_args(int fd, char *path, mode_t mode)
4297  *
4298  * Make a directory file.  The path is relative to the directory associated
4299  * with fd.
4300  */
4301 int
4302 sys_mkdirat(struct mkdirat_args *uap)
4303 {
4304 	struct nlookupdata nd;
4305 	struct file *fp;
4306 	int error;
4307 
4308 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
4309 	if (error == 0)
4310 		error = kern_mkdir(&nd, uap->mode);
4311 	nlookup_done_at(&nd, fp);
4312 	return (error);
4313 }
4314 
4315 int
4316 kern_rmdir(struct nlookupdata *nd)
4317 {
4318 	int error;
4319 
4320 	bwillinode(1);
4321 	nd->nl_flags |= NLC_DELETE | NLC_REFDVP;
4322 	if ((error = nlookup(nd)) != 0)
4323 		return (error);
4324 
4325 	/*
4326 	 * Do not allow directories representing mount points to be
4327 	 * deleted, even if empty.  Check write perms on mount point
4328 	 * in case the vnode is aliased (aka nullfs).
4329 	 */
4330 	if (nd->nl_nch.ncp->nc_flag & (NCF_ISMOUNTPT))
4331 		return (EBUSY);
4332 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
4333 		return (error);
4334 	error = VOP_NRMDIR(&nd->nl_nch, nd->nl_dvp, nd->nl_cred);
4335 	return (error);
4336 }
4337 
4338 /*
4339  * rmdir_args(char *path)
4340  *
4341  * Remove a directory file.
4342  */
4343 int
4344 sys_rmdir(struct rmdir_args *uap)
4345 {
4346 	struct nlookupdata nd;
4347 	int error;
4348 
4349 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
4350 	if (error == 0)
4351 		error = kern_rmdir(&nd);
4352 	nlookup_done(&nd);
4353 	return (error);
4354 }
4355 
4356 int
4357 kern_getdirentries(int fd, char *buf, u_int count, long *basep, int *res,
4358 		   enum uio_seg direction)
4359 {
4360 	struct thread *td = curthread;
4361 	struct vnode *vp;
4362 	struct file *fp;
4363 	struct uio auio;
4364 	struct iovec aiov;
4365 	off_t loff;
4366 	int error, eofflag;
4367 
4368 	if ((error = holdvnode(td, fd, &fp)) != 0)
4369 		return (error);
4370 	if ((fp->f_flag & FREAD) == 0) {
4371 		error = EBADF;
4372 		goto done;
4373 	}
4374 	vp = (struct vnode *)fp->f_data;
4375 	if (vp->v_type != VDIR) {
4376 		error = EINVAL;
4377 		goto done;
4378 	}
4379 	aiov.iov_base = buf;
4380 	aiov.iov_len = count;
4381 	auio.uio_iov = &aiov;
4382 	auio.uio_iovcnt = 1;
4383 	auio.uio_rw = UIO_READ;
4384 	auio.uio_segflg = direction;
4385 	auio.uio_td = td;
4386 	auio.uio_resid = count;
4387 	loff = auio.uio_offset = fp->f_offset;
4388 	error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, NULL, NULL);
4389 	fp->f_offset = auio.uio_offset;
4390 	if (error)
4391 		goto done;
4392 
4393 	/*
4394 	 * WARNING!  *basep may not be wide enough to accomodate the
4395 	 * seek offset.   XXX should we hack this to return the upper 32 bits
4396 	 * for offsets greater then 4G?
4397 	 */
4398 	if (basep) {
4399 		*basep = (long)loff;
4400 	}
4401 	*res = count - auio.uio_resid;
4402 done:
4403 	fdrop(fp);
4404 	return (error);
4405 }
4406 
4407 /*
4408  * getdirentries_args(int fd, char *buf, u_int conut, long *basep)
4409  *
4410  * Read a block of directory entries in a file system independent format.
4411  */
4412 int
4413 sys_getdirentries(struct getdirentries_args *uap)
4414 {
4415 	long base;
4416 	int error;
4417 
4418 	error = kern_getdirentries(uap->fd, uap->buf, uap->count, &base,
4419 				   &uap->sysmsg_result, UIO_USERSPACE);
4420 
4421 	if (error == 0 && uap->basep)
4422 		error = copyout(&base, uap->basep, sizeof(*uap->basep));
4423 	return (error);
4424 }
4425 
4426 /*
4427  * getdents_args(int fd, char *buf, size_t count)
4428  */
4429 int
4430 sys_getdents(struct getdents_args *uap)
4431 {
4432 	int error;
4433 
4434 	error = kern_getdirentries(uap->fd, uap->buf, uap->count, NULL,
4435 				   &uap->sysmsg_result, UIO_USERSPACE);
4436 
4437 	return (error);
4438 }
4439 
4440 /*
4441  * Set the mode mask for creation of filesystem nodes.
4442  *
4443  * umask(int newmask)
4444  */
4445 int
4446 sys_umask(struct umask_args *uap)
4447 {
4448 	struct thread *td = curthread;
4449 	struct proc *p = td->td_proc;
4450 	struct filedesc *fdp;
4451 
4452 	fdp = p->p_fd;
4453 	uap->sysmsg_result = fdp->fd_cmask;
4454 	fdp->fd_cmask = uap->newmask & ALLPERMS;
4455 	return (0);
4456 }
4457 
4458 /*
4459  * revoke(char *path)
4460  *
4461  * Void all references to file by ripping underlying filesystem
4462  * away from vnode.
4463  */
4464 int
4465 sys_revoke(struct revoke_args *uap)
4466 {
4467 	struct nlookupdata nd;
4468 	struct vattr vattr;
4469 	struct vnode *vp;
4470 	struct ucred *cred;
4471 	int error;
4472 
4473 	vp = NULL;
4474 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4475 	if (error == 0)
4476 		error = nlookup(&nd);
4477 	if (error == 0)
4478 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
4479 	cred = crhold(nd.nl_cred);
4480 	nlookup_done(&nd);
4481 	if (error == 0) {
4482 		if (error == 0)
4483 			error = VOP_GETATTR(vp, &vattr);
4484 		if (error == 0 && cred->cr_uid != vattr.va_uid)
4485 			error = priv_check_cred(cred, PRIV_VFS_REVOKE, 0);
4486 		if (error == 0 && (vp->v_type == VCHR || vp->v_type == VBLK)) {
4487 			if (vcount(vp) > 0)
4488 				error = vrevoke(vp, cred);
4489 		} else if (error == 0) {
4490 			error = vrevoke(vp, cred);
4491 		}
4492 		vrele(vp);
4493 	}
4494 	if (cred)
4495 		crfree(cred);
4496 	return (error);
4497 }
4498 
4499 /*
4500  * getfh_args(char *fname, fhandle_t *fhp)
4501  *
4502  * Get (NFS) file handle
4503  *
4504  * NOTE: We use the fsid of the covering mount, even if it is a nullfs
4505  * mount.  This allows nullfs mounts to be explicitly exported.
4506  *
4507  * WARNING: nullfs mounts of HAMMER PFS ROOTs are safe.
4508  *
4509  * 	    nullfs mounts of subdirectories are not safe.  That is, it will
4510  *	    work, but you do not really have protection against access to
4511  *	    the related parent directories.
4512  */
4513 int
4514 sys_getfh(struct getfh_args *uap)
4515 {
4516 	struct thread *td = curthread;
4517 	struct nlookupdata nd;
4518 	fhandle_t fh;
4519 	struct vnode *vp;
4520 	struct mount *mp;
4521 	int error;
4522 
4523 	/*
4524 	 * Must be super user
4525 	 */
4526 	if ((error = priv_check(td, PRIV_ROOT)) != 0)
4527 		return (error);
4528 
4529 	vp = NULL;
4530 	error = nlookup_init(&nd, uap->fname, UIO_USERSPACE, NLC_FOLLOW);
4531 	if (error == 0)
4532 		error = nlookup(&nd);
4533 	if (error == 0)
4534 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
4535 	mp = nd.nl_nch.mount;
4536 	nlookup_done(&nd);
4537 	if (error == 0) {
4538 		bzero(&fh, sizeof(fh));
4539 		fh.fh_fsid = mp->mnt_stat.f_fsid;
4540 		error = VFS_VPTOFH(vp, &fh.fh_fid);
4541 		vput(vp);
4542 		if (error == 0)
4543 			error = copyout(&fh, uap->fhp, sizeof(fh));
4544 	}
4545 	return (error);
4546 }
4547 
4548 /*
4549  * fhopen_args(const struct fhandle *u_fhp, int flags)
4550  *
4551  * syscall for the rpc.lockd to use to translate a NFS file handle into
4552  * an open descriptor.
4553  *
4554  * warning: do not remove the priv_check() call or this becomes one giant
4555  * security hole.
4556  */
4557 int
4558 sys_fhopen(struct fhopen_args *uap)
4559 {
4560 	struct thread *td = curthread;
4561 	struct filedesc *fdp = td->td_proc->p_fd;
4562 	struct mount *mp;
4563 	struct vnode *vp;
4564 	struct fhandle fhp;
4565 	struct vattr vat;
4566 	struct vattr *vap = &vat;
4567 	struct flock lf;
4568 	int fmode, mode, error = 0, type;
4569 	struct file *nfp;
4570 	struct file *fp;
4571 	int indx;
4572 
4573 	/*
4574 	 * Must be super user
4575 	 */
4576 	error = priv_check(td, PRIV_ROOT);
4577 	if (error)
4578 		return (error);
4579 
4580 	fmode = FFLAGS(uap->flags);
4581 
4582 	/*
4583 	 * Why not allow a non-read/write open for our lockd?
4584 	 */
4585 	if (((fmode & (FREAD | FWRITE)) == 0) || (fmode & O_CREAT))
4586 		return (EINVAL);
4587 	error = copyin(uap->u_fhp, &fhp, sizeof(fhp));
4588 	if (error)
4589 		return(error);
4590 
4591 	/*
4592 	 * Find the mount point
4593 	 */
4594 	mp = vfs_getvfs(&fhp.fh_fsid);
4595 	if (mp == NULL) {
4596 		error = ESTALE;
4597 		goto done2;
4598 	}
4599 	/* now give me my vnode, it gets returned to me locked */
4600 	error = VFS_FHTOVP(mp, NULL, &fhp.fh_fid, &vp);
4601 	if (error)
4602 		goto done;
4603  	/*
4604 	 * from now on we have to make sure not
4605 	 * to forget about the vnode
4606 	 * any error that causes an abort must vput(vp)
4607 	 * just set error = err and 'goto bad;'.
4608 	 */
4609 
4610 	/*
4611 	 * from vn_open
4612 	 */
4613 	if (vp->v_type == VLNK) {
4614 		error = EMLINK;
4615 		goto bad;
4616 	}
4617 	if (vp->v_type == VSOCK) {
4618 		error = EOPNOTSUPP;
4619 		goto bad;
4620 	}
4621 	mode = 0;
4622 	if (fmode & (FWRITE | O_TRUNC)) {
4623 		if (vp->v_type == VDIR) {
4624 			error = EISDIR;
4625 			goto bad;
4626 		}
4627 		error = vn_writechk(vp, NULL);
4628 		if (error)
4629 			goto bad;
4630 		mode |= VWRITE;
4631 	}
4632 	if (fmode & FREAD)
4633 		mode |= VREAD;
4634 	if (mode) {
4635 		error = VOP_ACCESS(vp, mode, td->td_ucred);
4636 		if (error)
4637 			goto bad;
4638 	}
4639 	if (fmode & O_TRUNC) {
4640 		vn_unlock(vp);				/* XXX */
4641 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);	/* XXX */
4642 		VATTR_NULL(vap);
4643 		vap->va_size = 0;
4644 		error = VOP_SETATTR(vp, vap, td->td_ucred);
4645 		if (error)
4646 			goto bad;
4647 	}
4648 
4649 	/*
4650 	 * VOP_OPEN needs the file pointer so it can potentially override
4651 	 * it.
4652 	 *
4653 	 * WARNING! no f_nchandle will be associated when fhopen()ing a
4654 	 * directory.  XXX
4655 	 */
4656 	if ((error = falloc(td->td_lwp, &nfp, &indx)) != 0)
4657 		goto bad;
4658 	fp = nfp;
4659 
4660 	error = VOP_OPEN(vp, fmode, td->td_ucred, fp);
4661 	if (error) {
4662 		/*
4663 		 * setting f_ops this way prevents VOP_CLOSE from being
4664 		 * called or fdrop() releasing the vp from v_data.   Since
4665 		 * the VOP_OPEN failed we don't want to VOP_CLOSE.
4666 		 */
4667 		fp->f_ops = &badfileops;
4668 		fp->f_data = NULL;
4669 		goto bad_drop;
4670 	}
4671 
4672 	/*
4673 	 * The fp is given its own reference, we still have our ref and lock.
4674 	 *
4675 	 * Assert that all regular files must be created with a VM object.
4676 	 */
4677 	if (vp->v_type == VREG && vp->v_object == NULL) {
4678 		kprintf("fhopen: regular file did not "
4679 			"have VM object: %p\n",
4680 			vp);
4681 		goto bad_drop;
4682 	}
4683 
4684 	/*
4685 	 * The open was successful.  Handle any locking requirements.
4686 	 */
4687 	if (fmode & (O_EXLOCK | O_SHLOCK)) {
4688 		lf.l_whence = SEEK_SET;
4689 		lf.l_start = 0;
4690 		lf.l_len = 0;
4691 		if (fmode & O_EXLOCK)
4692 			lf.l_type = F_WRLCK;
4693 		else
4694 			lf.l_type = F_RDLCK;
4695 		if (fmode & FNONBLOCK)
4696 			type = 0;
4697 		else
4698 			type = F_WAIT;
4699 		vn_unlock(vp);
4700 		if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK,
4701 					 &lf, type)) != 0) {
4702 			/*
4703 			 * release our private reference.
4704 			 */
4705 			fsetfd(fdp, NULL, indx);
4706 			fdrop(fp);
4707 			vrele(vp);
4708 			goto done;
4709 		}
4710 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
4711 		atomic_set_int(&fp->f_flag, FHASLOCK);	/* race ok */
4712 	}
4713 
4714 	/*
4715 	 * Clean up.  Associate the file pointer with the previously
4716 	 * reserved descriptor and return it.
4717 	 */
4718 	vput(vp);
4719 	if (uap->flags & O_CLOEXEC)
4720 		fdp->fd_files[indx].fileflags |= UF_EXCLOSE;
4721 	fsetfd(fdp, fp, indx);
4722 	fdrop(fp);
4723 	uap->sysmsg_result = indx;
4724 	mount_drop(mp);
4725 
4726 	return (error);
4727 
4728 bad_drop:
4729 	fsetfd(fdp, NULL, indx);
4730 	fdrop(fp);
4731 bad:
4732 	vput(vp);
4733 done:
4734 	mount_drop(mp);
4735 done2:
4736 	return (error);
4737 }
4738 
4739 /*
4740  * fhstat_args(struct fhandle *u_fhp, struct stat *sb)
4741  */
4742 int
4743 sys_fhstat(struct fhstat_args *uap)
4744 {
4745 	struct thread *td = curthread;
4746 	struct stat sb;
4747 	fhandle_t fh;
4748 	struct mount *mp;
4749 	struct vnode *vp;
4750 	int error;
4751 
4752 	/*
4753 	 * Must be super user
4754 	 */
4755 	error = priv_check(td, PRIV_ROOT);
4756 	if (error)
4757 		return (error);
4758 
4759 	error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t));
4760 	if (error)
4761 		return (error);
4762 
4763 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL)
4764 		error = ESTALE;
4765 	if (error == 0) {
4766 		if ((error = VFS_FHTOVP(mp, NULL, &fh.fh_fid, &vp)) == 0) {
4767 			error = vn_stat(vp, &sb, td->td_ucred);
4768 			vput(vp);
4769 		}
4770 	}
4771 	if (error == 0)
4772 		error = copyout(&sb, uap->sb, sizeof(sb));
4773 	if (mp)
4774 		mount_drop(mp);
4775 
4776 	return (error);
4777 }
4778 
4779 /*
4780  * fhstatfs_args(struct fhandle *u_fhp, struct statfs *buf)
4781  */
4782 int
4783 sys_fhstatfs(struct fhstatfs_args *uap)
4784 {
4785 	struct thread *td = curthread;
4786 	struct proc *p = td->td_proc;
4787 	struct statfs *sp;
4788 	struct mount *mp;
4789 	struct vnode *vp;
4790 	struct statfs sb;
4791 	char *fullpath, *freepath;
4792 	fhandle_t fh;
4793 	int error;
4794 
4795 	/*
4796 	 * Must be super user
4797 	 */
4798 	if ((error = priv_check(td, PRIV_ROOT)))
4799 		return (error);
4800 
4801 	if ((error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t))) != 0)
4802 		return (error);
4803 
4804 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL) {
4805 		error = ESTALE;
4806 		goto done;
4807 	}
4808 	if (p != NULL && !chroot_visible_mnt(mp, p)) {
4809 		error = ESTALE;
4810 		goto done;
4811 	}
4812 
4813 	if ((error = VFS_FHTOVP(mp, NULL, &fh.fh_fid, &vp)) != 0)
4814 		goto done;
4815 	mp = vp->v_mount;
4816 	sp = &mp->mnt_stat;
4817 	vput(vp);
4818 	if ((error = VFS_STATFS(mp, sp, td->td_ucred)) != 0)
4819 		goto done;
4820 
4821 	error = mount_path(p, mp, &fullpath, &freepath);
4822 	if (error)
4823 		goto done;
4824 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
4825 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
4826 	kfree(freepath, M_TEMP);
4827 
4828 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
4829 	if (priv_check(td, PRIV_ROOT)) {
4830 		bcopy(sp, &sb, sizeof(sb));
4831 		sb.f_fsid.val[0] = sb.f_fsid.val[1] = 0;
4832 		sp = &sb;
4833 	}
4834 	error = copyout(sp, uap->buf, sizeof(*sp));
4835 done:
4836 	if (mp)
4837 		mount_drop(mp);
4838 
4839 	return (error);
4840 }
4841 
4842 /*
4843  * fhstatvfs_args(struct fhandle *u_fhp, struct statvfs *buf)
4844  */
4845 int
4846 sys_fhstatvfs(struct fhstatvfs_args *uap)
4847 {
4848 	struct thread *td = curthread;
4849 	struct proc *p = td->td_proc;
4850 	struct statvfs *sp;
4851 	struct mount *mp;
4852 	struct vnode *vp;
4853 	fhandle_t fh;
4854 	int error;
4855 
4856 	/*
4857 	 * Must be super user
4858 	 */
4859 	if ((error = priv_check(td, PRIV_ROOT)))
4860 		return (error);
4861 
4862 	if ((error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t))) != 0)
4863 		return (error);
4864 
4865 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL) {
4866 		error = ESTALE;
4867 		goto done;
4868 	}
4869 	if (p != NULL && !chroot_visible_mnt(mp, p)) {
4870 		error = ESTALE;
4871 		goto done;
4872 	}
4873 
4874 	if ((error = VFS_FHTOVP(mp, NULL, &fh.fh_fid, &vp)))
4875 		goto done;
4876 	mp = vp->v_mount;
4877 	sp = &mp->mnt_vstat;
4878 	vput(vp);
4879 	if ((error = VFS_STATVFS(mp, sp, td->td_ucred)) != 0)
4880 		goto done;
4881 
4882 	sp->f_flag = 0;
4883 	if (mp->mnt_flag & MNT_RDONLY)
4884 		sp->f_flag |= ST_RDONLY;
4885 	if (mp->mnt_flag & MNT_NOSUID)
4886 		sp->f_flag |= ST_NOSUID;
4887 	error = copyout(sp, uap->buf, sizeof(*sp));
4888 done:
4889 	if (mp)
4890 		mount_drop(mp);
4891 	return (error);
4892 }
4893 
4894 
4895 /*
4896  * Syscall to push extended attribute configuration information into the
4897  * VFS.  Accepts a path, which it converts to a mountpoint, as well as
4898  * a command (int cmd), and attribute name and misc data.  For now, the
4899  * attribute name is left in userspace for consumption by the VFS_op.
4900  * It will probably be changed to be copied into sysspace by the
4901  * syscall in the future, once issues with various consumers of the
4902  * attribute code have raised their hands.
4903  *
4904  * Currently this is used only by UFS Extended Attributes.
4905  */
4906 int
4907 sys_extattrctl(struct extattrctl_args *uap)
4908 {
4909 	struct nlookupdata nd;
4910 	struct vnode *vp;
4911 	char attrname[EXTATTR_MAXNAMELEN];
4912 	int error;
4913 	size_t size;
4914 
4915 	attrname[0] = 0;
4916 	vp = NULL;
4917 	error = 0;
4918 
4919 	if (error == 0 && uap->filename) {
4920 		error = nlookup_init(&nd, uap->filename, UIO_USERSPACE,
4921 				     NLC_FOLLOW);
4922 		if (error == 0)
4923 			error = nlookup(&nd);
4924 		if (error == 0)
4925 			error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
4926 		nlookup_done(&nd);
4927 	}
4928 
4929 	if (error == 0 && uap->attrname) {
4930 		error = copyinstr(uap->attrname, attrname, EXTATTR_MAXNAMELEN,
4931 				  &size);
4932 	}
4933 
4934 	if (error == 0) {
4935 		error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4936 		if (error == 0)
4937 			error = nlookup(&nd);
4938 		if (error == 0)
4939 			error = ncp_writechk(&nd.nl_nch);
4940 		if (error == 0) {
4941 			error = VFS_EXTATTRCTL(nd.nl_nch.mount, uap->cmd, vp,
4942 					       uap->attrnamespace,
4943 					       uap->attrname, nd.nl_cred);
4944 		}
4945 		nlookup_done(&nd);
4946 	}
4947 
4948 	return (error);
4949 }
4950 
4951 /*
4952  * Syscall to get a named extended attribute on a file or directory.
4953  */
4954 int
4955 sys_extattr_set_file(struct extattr_set_file_args *uap)
4956 {
4957 	char attrname[EXTATTR_MAXNAMELEN];
4958 	struct nlookupdata nd;
4959 	struct vnode *vp;
4960 	struct uio auio;
4961 	struct iovec aiov;
4962 	int error;
4963 
4964 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
4965 	if (error)
4966 		return (error);
4967 
4968 	vp = NULL;
4969 
4970 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4971 	if (error == 0)
4972 		error = nlookup(&nd);
4973 	if (error == 0)
4974 		error = ncp_writechk(&nd.nl_nch);
4975 	if (error == 0)
4976 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
4977 	if (error) {
4978 		nlookup_done(&nd);
4979 		return (error);
4980 	}
4981 
4982 	bzero(&auio, sizeof(auio));
4983 	aiov.iov_base = uap->data;
4984 	aiov.iov_len = uap->nbytes;
4985 	auio.uio_iov = &aiov;
4986 	auio.uio_iovcnt = 1;
4987 	auio.uio_offset = 0;
4988 	auio.uio_resid = uap->nbytes;
4989 	auio.uio_rw = UIO_WRITE;
4990 	auio.uio_td = curthread;
4991 
4992 	error = VOP_SETEXTATTR(vp, uap->attrnamespace, attrname,
4993 			       &auio, nd.nl_cred);
4994 
4995 	vput(vp);
4996 	nlookup_done(&nd);
4997 	return (error);
4998 }
4999 
5000 /*
5001  * Syscall to get a named extended attribute on a file or directory.
5002  */
5003 int
5004 sys_extattr_get_file(struct extattr_get_file_args *uap)
5005 {
5006 	char attrname[EXTATTR_MAXNAMELEN];
5007 	struct nlookupdata nd;
5008 	struct uio auio;
5009 	struct iovec aiov;
5010 	struct vnode *vp;
5011 	int error;
5012 
5013 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
5014 	if (error)
5015 		return (error);
5016 
5017 	vp = NULL;
5018 
5019 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
5020 	if (error == 0)
5021 		error = nlookup(&nd);
5022 	if (error == 0)
5023 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_SHARED, &vp);
5024 	if (error) {
5025 		nlookup_done(&nd);
5026 		return (error);
5027 	}
5028 
5029 	bzero(&auio, sizeof(auio));
5030 	aiov.iov_base = uap->data;
5031 	aiov.iov_len = uap->nbytes;
5032 	auio.uio_iov = &aiov;
5033 	auio.uio_iovcnt = 1;
5034 	auio.uio_offset = 0;
5035 	auio.uio_resid = uap->nbytes;
5036 	auio.uio_rw = UIO_READ;
5037 	auio.uio_td = curthread;
5038 
5039 	error = VOP_GETEXTATTR(vp, uap->attrnamespace, attrname,
5040 				&auio, nd.nl_cred);
5041 	uap->sysmsg_result = uap->nbytes - auio.uio_resid;
5042 
5043 	vput(vp);
5044 	nlookup_done(&nd);
5045 	return(error);
5046 }
5047 
5048 /*
5049  * Syscall to delete a named extended attribute from a file or directory.
5050  * Accepts attribute name.  The real work happens in VOP_SETEXTATTR().
5051  */
5052 int
5053 sys_extattr_delete_file(struct extattr_delete_file_args *uap)
5054 {
5055 	char attrname[EXTATTR_MAXNAMELEN];
5056 	struct nlookupdata nd;
5057 	struct vnode *vp;
5058 	int error;
5059 
5060 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
5061 	if (error)
5062 		return(error);
5063 
5064 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
5065 	if (error == 0)
5066 		error = nlookup(&nd);
5067 	if (error == 0)
5068 		error = ncp_writechk(&nd.nl_nch);
5069 	if (error == 0) {
5070 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
5071 		if (error == 0) {
5072 			error = VOP_SETEXTATTR(vp, uap->attrnamespace,
5073 					       attrname, NULL, nd.nl_cred);
5074 			vput(vp);
5075 		}
5076 	}
5077 	nlookup_done(&nd);
5078 	return(error);
5079 }
5080 
5081 /*
5082  * Determine if the mount is visible to the process.
5083  */
5084 static int
5085 chroot_visible_mnt(struct mount *mp, struct proc *p)
5086 {
5087 	struct nchandle nch;
5088 
5089 	/*
5090 	 * Traverse from the mount point upwards.  If we hit the process
5091 	 * root then the mount point is visible to the process.
5092 	 */
5093 	nch = mp->mnt_ncmountpt;
5094 	while (nch.ncp) {
5095 		if (nch.mount == p->p_fd->fd_nrdir.mount &&
5096 		    nch.ncp == p->p_fd->fd_nrdir.ncp) {
5097 			return(1);
5098 		}
5099 		if (nch.ncp == nch.mount->mnt_ncmountpt.ncp) {
5100 			nch = nch.mount->mnt_ncmounton;
5101 		} else {
5102 			nch.ncp = nch.ncp->nc_parent;
5103 		}
5104 	}
5105 
5106 	/*
5107 	 * If the mount point is not visible to the process, but the
5108 	 * process root is in a subdirectory of the mount, return
5109 	 * TRUE anyway.
5110 	 */
5111 	if (p->p_fd->fd_nrdir.mount == mp)
5112 		return(1);
5113 
5114 	return(0);
5115 }
5116 
5117