xref: /dragonfly/sys/kern/vfs_syscalls.c (revision 52f9f0d9)
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. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)vfs_syscalls.c	8.13 (Berkeley) 4/15/94
39  * $FreeBSD: src/sys/kern/vfs_syscalls.c,v 1.151.2.18 2003/04/04 20:35:58 tegge Exp $
40  */
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/buf.h>
45 #include <sys/conf.h>
46 #include <sys/sysent.h>
47 #include <sys/malloc.h>
48 #include <sys/mount.h>
49 #include <sys/mountctl.h>
50 #include <sys/sysproto.h>
51 #include <sys/filedesc.h>
52 #include <sys/kernel.h>
53 #include <sys/fcntl.h>
54 #include <sys/file.h>
55 #include <sys/linker.h>
56 #include <sys/stat.h>
57 #include <sys/unistd.h>
58 #include <sys/vnode.h>
59 #include <sys/proc.h>
60 #include <sys/priv.h>
61 #include <sys/jail.h>
62 #include <sys/namei.h>
63 #include <sys/nlookup.h>
64 #include <sys/dirent.h>
65 #include <sys/extattr.h>
66 #include <sys/spinlock.h>
67 #include <sys/kern_syscall.h>
68 #include <sys/objcache.h>
69 #include <sys/sysctl.h>
70 
71 #include <sys/buf2.h>
72 #include <sys/file2.h>
73 #include <sys/spinlock2.h>
74 #include <sys/mplock2.h>
75 
76 #include <vm/vm.h>
77 #include <vm/vm_object.h>
78 #include <vm/vm_page.h>
79 
80 #include <machine/limits.h>
81 #include <machine/stdarg.h>
82 
83 #include <vfs/union/union.h>
84 
85 static void mount_warning(struct mount *mp, const char *ctl, ...)
86 		__printflike(2, 3);
87 static int mount_path(struct proc *p, struct mount *mp, char **rb, char **fb);
88 static int checkvp_chdir (struct vnode *vn, struct thread *td);
89 static void checkdirs (struct nchandle *old_nch, struct nchandle *new_nch);
90 static int chroot_refuse_vdir_fds (struct filedesc *fdp);
91 static int chroot_visible_mnt(struct mount *mp, struct proc *p);
92 static int getutimes (const struct timeval *, struct timespec *);
93 static int setfown (struct mount *, struct vnode *, uid_t, gid_t);
94 static int setfmode (struct vnode *, int);
95 static int setfflags (struct vnode *, int);
96 static int setutimes (struct vnode *, struct vattr *,
97 			const struct timespec *, int);
98 static int	usermount = 0;	/* if 1, non-root can mount fs. */
99 
100 int (*union_dircheckp) (struct thread *, struct vnode **, struct file *);
101 
102 SYSCTL_INT(_vfs, OID_AUTO, usermount, CTLFLAG_RW, &usermount, 0,
103     "Allow non-root users to mount filesystems");
104 
105 /*
106  * Virtual File System System Calls
107  */
108 
109 /*
110  * Mount a file system.
111  *
112  * mount_args(char *type, char *path, int flags, caddr_t data)
113  *
114  * MPALMOSTSAFE
115  */
116 int
117 sys_mount(struct mount_args *uap)
118 {
119 	struct thread *td = curthread;
120 	struct vnode *vp;
121 	struct nchandle nch;
122 	struct mount *mp, *nullmp;
123 	struct vfsconf *vfsp;
124 	int error, flag = 0, flag2 = 0;
125 	int hasmount;
126 	struct vattr va;
127 	struct nlookupdata nd;
128 	char fstypename[MFSNAMELEN];
129 	struct ucred *cred;
130 
131 	get_mplock();
132 	cred = td->td_ucred;
133 	if (jailed(cred)) {
134 		error = EPERM;
135 		goto done;
136 	}
137 	if (usermount == 0 && (error = priv_check(td, PRIV_ROOT)))
138 		goto done;
139 
140 	/*
141 	 * Do not allow NFS export by non-root users.
142 	 */
143 	if (uap->flags & MNT_EXPORTED) {
144 		error = priv_check(td, PRIV_ROOT);
145 		if (error)
146 			goto done;
147 	}
148 	/*
149 	 * Silently enforce MNT_NOSUID and MNT_NODEV for non-root users
150 	 */
151 	if (priv_check(td, PRIV_ROOT))
152 		uap->flags |= MNT_NOSUID | MNT_NODEV;
153 
154 	/*
155 	 * Lookup the requested path and extract the nch and vnode.
156 	 */
157 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
158 	if (error == 0) {
159 		if ((error = nlookup(&nd)) == 0) {
160 			if (nd.nl_nch.ncp->nc_vp == NULL)
161 				error = ENOENT;
162 		}
163 	}
164 	if (error) {
165 		nlookup_done(&nd);
166 		goto done;
167 	}
168 
169 	/*
170 	 * If the target filesystem is resolved via a nullfs mount, then
171 	 * nd.nl_nch.mount will be pointing to the nullfs mount structure
172 	 * instead of the target file system. We need it in case we are
173 	 * doing an update.
174 	 */
175 	nullmp = nd.nl_nch.mount;
176 
177 	/*
178 	 * Extract the locked+refd ncp and cleanup the nd structure
179 	 */
180 	nch = nd.nl_nch;
181 	cache_zero(&nd.nl_nch);
182 	nlookup_done(&nd);
183 
184 	if ((nch.ncp->nc_flag & NCF_ISMOUNTPT) &&
185 	    (mp = cache_findmount(&nch)) != NULL) {
186 		cache_dropmount(mp);
187 		hasmount = 1;
188 	} else {
189 		hasmount = 0;
190 	}
191 
192 
193 	/*
194 	 * now we have the locked ref'd nch and unreferenced vnode.
195 	 */
196 	vp = nch.ncp->nc_vp;
197 	if ((error = vget(vp, LK_EXCLUSIVE)) != 0) {
198 		cache_put(&nch);
199 		goto done;
200 	}
201 	cache_unlock(&nch);
202 
203 	/*
204 	 * Extract the file system type. We need to know this early, to take
205 	 * appropriate actions if we are dealing with a nullfs.
206 	 */
207         if ((error = copyinstr(uap->type, fstypename, MFSNAMELEN, NULL)) != 0) {
208                 cache_drop(&nch);
209                 vput(vp);
210 		goto done;
211         }
212 
213 	/*
214 	 * Now we have an unlocked ref'd nch and a locked ref'd vp
215 	 */
216 	if (uap->flags & MNT_UPDATE) {
217 		if ((vp->v_flag & (VROOT|VPFSROOT)) == 0) {
218 			cache_drop(&nch);
219 			vput(vp);
220 			error = EINVAL;
221 			goto done;
222 		}
223 
224 		if (strncmp(fstypename, "null", 5) == 0) {
225 			KKASSERT(nullmp);
226 			mp = nullmp;
227 		} else {
228 			mp = vp->v_mount;
229 		}
230 
231 		flag = mp->mnt_flag;
232 		flag2 = mp->mnt_kern_flag;
233 		/*
234 		 * We only allow the filesystem to be reloaded if it
235 		 * is currently mounted read-only.
236 		 */
237 		if ((uap->flags & MNT_RELOAD) &&
238 		    ((mp->mnt_flag & MNT_RDONLY) == 0)) {
239 			cache_drop(&nch);
240 			vput(vp);
241 			error = EOPNOTSUPP;	/* Needs translation */
242 			goto done;
243 		}
244 		/*
245 		 * Only root, or the user that did the original mount is
246 		 * permitted to update it.
247 		 */
248 		if (mp->mnt_stat.f_owner != cred->cr_uid &&
249 		    (error = priv_check(td, PRIV_ROOT))) {
250 			cache_drop(&nch);
251 			vput(vp);
252 			goto done;
253 		}
254 		if (vfs_busy(mp, LK_NOWAIT)) {
255 			cache_drop(&nch);
256 			vput(vp);
257 			error = EBUSY;
258 			goto done;
259 		}
260 		if ((vp->v_flag & VMOUNT) != 0 || hasmount) {
261 			cache_drop(&nch);
262 			vfs_unbusy(mp);
263 			vput(vp);
264 			error = EBUSY;
265 			goto done;
266 		}
267 		vsetflags(vp, VMOUNT);
268 		mp->mnt_flag |=
269 		    uap->flags & (MNT_RELOAD | MNT_FORCE | MNT_UPDATE);
270 		vn_unlock(vp);
271 		goto update;
272 	}
273 	/*
274 	 * If the user is not root, ensure that they own the directory
275 	 * onto which we are attempting to mount.
276 	 */
277 	if ((error = VOP_GETATTR(vp, &va)) ||
278 	    (va.va_uid != cred->cr_uid && (error = priv_check(td, PRIV_ROOT)))) {
279 		cache_drop(&nch);
280 		vput(vp);
281 		goto done;
282 	}
283 	if ((error = vinvalbuf(vp, V_SAVE, 0, 0)) != 0) {
284 		cache_drop(&nch);
285 		vput(vp);
286 		goto done;
287 	}
288 	if (vp->v_type != VDIR) {
289 		cache_drop(&nch);
290 		vput(vp);
291 		error = ENOTDIR;
292 		goto done;
293 	}
294 	if (vp->v_mount->mnt_kern_flag & MNTK_NOSTKMNT) {
295 		cache_drop(&nch);
296 		vput(vp);
297 		error = EPERM;
298 		goto done;
299 	}
300 	vfsp = vfsconf_find_by_name(fstypename);
301 	if (vfsp == NULL) {
302 		linker_file_t lf;
303 
304 		/* Only load modules for root (very important!) */
305 		if ((error = priv_check(td, PRIV_ROOT)) != 0) {
306 			cache_drop(&nch);
307 			vput(vp);
308 			goto done;
309 		}
310 		error = linker_load_file(fstypename, &lf);
311 		if (error || lf == NULL) {
312 			cache_drop(&nch);
313 			vput(vp);
314 			if (lf == NULL)
315 				error = ENODEV;
316 			goto done;
317 		}
318 		lf->userrefs++;
319 		/* lookup again, see if the VFS was loaded */
320 		vfsp = vfsconf_find_by_name(fstypename);
321 		if (vfsp == NULL) {
322 			lf->userrefs--;
323 			linker_file_unload(lf);
324 			cache_drop(&nch);
325 			vput(vp);
326 			error = ENODEV;
327 			goto done;
328 		}
329 	}
330 	if ((vp->v_flag & VMOUNT) != 0 || hasmount) {
331 		cache_drop(&nch);
332 		vput(vp);
333 		error = EBUSY;
334 		goto done;
335 	}
336 	vsetflags(vp, VMOUNT);
337 
338 	/*
339 	 * Allocate and initialize the filesystem.
340 	 */
341 	mp = kmalloc(sizeof(struct mount), M_MOUNT, M_ZERO|M_WAITOK);
342 	mount_init(mp);
343 	vfs_busy(mp, LK_NOWAIT);
344 	mp->mnt_op = vfsp->vfc_vfsops;
345 	mp->mnt_vfc = vfsp;
346 	vfsp->vfc_refcount++;
347 	mp->mnt_stat.f_type = vfsp->vfc_typenum;
348 	mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
349 	strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
350 	mp->mnt_stat.f_owner = cred->cr_uid;
351 	vn_unlock(vp);
352 update:
353 	/*
354 	 * Set the mount level flags.
355 	 */
356 	if (uap->flags & MNT_RDONLY)
357 		mp->mnt_flag |= MNT_RDONLY;
358 	else if (mp->mnt_flag & MNT_RDONLY)
359 		mp->mnt_kern_flag |= MNTK_WANTRDWR;
360 	mp->mnt_flag &=~ (MNT_NOSUID | MNT_NOEXEC | MNT_NODEV |
361 	    MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_NOATIME |
362 	    MNT_NOSYMFOLLOW | MNT_IGNORE | MNT_TRIM |
363 	    MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR);
364 	mp->mnt_flag |= uap->flags & (MNT_NOSUID | MNT_NOEXEC |
365 	    MNT_NODEV | MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_FORCE |
366 	    MNT_NOSYMFOLLOW | MNT_IGNORE | MNT_TRIM |
367 	    MNT_NOATIME | MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR);
368 	/*
369 	 * Mount the filesystem.
370 	 * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
371 	 * get.
372 	 */
373 	error = VFS_MOUNT(mp, uap->path, uap->data, cred);
374 	if (mp->mnt_flag & MNT_UPDATE) {
375 		if (mp->mnt_kern_flag & MNTK_WANTRDWR)
376 			mp->mnt_flag &= ~MNT_RDONLY;
377 		mp->mnt_flag &=~ (MNT_UPDATE | MNT_RELOAD | MNT_FORCE);
378 		mp->mnt_kern_flag &=~ MNTK_WANTRDWR;
379 		if (error) {
380 			mp->mnt_flag = flag;
381 			mp->mnt_kern_flag = flag2;
382 		}
383 		vfs_unbusy(mp);
384 		vclrflags(vp, VMOUNT);
385 		vrele(vp);
386 		cache_drop(&nch);
387 		goto done;
388 	}
389 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
390 	/*
391 	 * Put the new filesystem on the mount list after root.  The mount
392 	 * point gets its own mnt_ncmountpt (unless the VFS already set one
393 	 * up) which represents the root of the mount.  The lookup code
394 	 * detects the mount point going forward and checks the root of
395 	 * the mount going backwards.
396 	 *
397 	 * It is not necessary to invalidate or purge the vnode underneath
398 	 * because elements under the mount will be given their own glue
399 	 * namecache record.
400 	 */
401 	if (!error) {
402 		if (mp->mnt_ncmountpt.ncp == NULL) {
403 			/*
404 			 * allocate, then unlock, but leave the ref intact
405 			 */
406 			cache_allocroot(&mp->mnt_ncmountpt, mp, NULL);
407 			cache_unlock(&mp->mnt_ncmountpt);
408 		}
409 		mp->mnt_ncmounton = nch;		/* inherits ref */
410 		nch.ncp->nc_flag |= NCF_ISMOUNTPT;
411 
412 		/* XXX get the root of the fs and cache_setvp(mnt_ncmountpt...) */
413 		vclrflags(vp, VMOUNT);
414 		mountlist_insert(mp, MNTINS_LAST);
415 		vn_unlock(vp);
416 		checkdirs(&mp->mnt_ncmounton, &mp->mnt_ncmountpt);
417 		error = vfs_allocate_syncvnode(mp);
418 		vfs_unbusy(mp);
419 		error = VFS_START(mp, 0);
420 		vrele(vp);
421 	} else {
422 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
423 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
424 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
425 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
426 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
427 		vclrflags(vp, VMOUNT);
428 		mp->mnt_vfc->vfc_refcount--;
429 		vfs_unbusy(mp);
430 		kfree(mp, M_MOUNT);
431 		cache_drop(&nch);
432 		vput(vp);
433 	}
434 done:
435 	rel_mplock();
436 	return (error);
437 }
438 
439 /*
440  * Scan all active processes to see if any of them have a current
441  * or root directory onto which the new filesystem has just been
442  * mounted. If so, replace them with the new mount point.
443  *
444  * The passed ncp is ref'd and locked (from the mount code) and
445  * must be associated with the vnode representing the root of the
446  * mount point.
447  */
448 struct checkdirs_info {
449 	struct nchandle old_nch;
450 	struct nchandle new_nch;
451 	struct vnode *old_vp;
452 	struct vnode *new_vp;
453 };
454 
455 static int checkdirs_callback(struct proc *p, void *data);
456 
457 static void
458 checkdirs(struct nchandle *old_nch, struct nchandle *new_nch)
459 {
460 	struct checkdirs_info info;
461 	struct vnode *olddp;
462 	struct vnode *newdp;
463 	struct mount *mp;
464 
465 	/*
466 	 * If the old mount point's vnode has a usecount of 1, it is not
467 	 * being held as a descriptor anywhere.
468 	 */
469 	olddp = old_nch->ncp->nc_vp;
470 	if (olddp == NULL || olddp->v_sysref.refcnt == 1)
471 		return;
472 
473 	/*
474 	 * Force the root vnode of the new mount point to be resolved
475 	 * so we can update any matching processes.
476 	 */
477 	mp = new_nch->mount;
478 	if (VFS_ROOT(mp, &newdp))
479 		panic("mount: lost mount");
480 	cache_setunresolved(new_nch);
481 	cache_setvp(new_nch, newdp);
482 
483 	/*
484 	 * Special handling of the root node
485 	 */
486 	if (rootvnode == olddp) {
487 		vref(newdp);
488 		vfs_cache_setroot(newdp, cache_hold(new_nch));
489 	}
490 
491 	/*
492 	 * Pass newdp separately so the callback does not have to access
493 	 * it via new_nch->ncp->nc_vp.
494 	 */
495 	info.old_nch = *old_nch;
496 	info.new_nch = *new_nch;
497 	info.new_vp = newdp;
498 	allproc_scan(checkdirs_callback, &info);
499 	vput(newdp);
500 }
501 
502 /*
503  * NOTE: callback is not MP safe because the scanned process's filedesc
504  * structure can be ripped out from under us, amoung other things.
505  */
506 static int
507 checkdirs_callback(struct proc *p, void *data)
508 {
509 	struct checkdirs_info *info = data;
510 	struct filedesc *fdp;
511 	struct nchandle ncdrop1;
512 	struct nchandle ncdrop2;
513 	struct vnode *vprele1;
514 	struct vnode *vprele2;
515 
516 	if ((fdp = p->p_fd) != NULL) {
517 		cache_zero(&ncdrop1);
518 		cache_zero(&ncdrop2);
519 		vprele1 = NULL;
520 		vprele2 = NULL;
521 
522 		/*
523 		 * MPUNSAFE - XXX fdp can be pulled out from under a
524 		 * foreign process.
525 		 *
526 		 * A shared filedesc is ok, we don't have to copy it
527 		 * because we are making this change globally.
528 		 */
529 		spin_lock(&fdp->fd_spin);
530 		if (fdp->fd_ncdir.mount == info->old_nch.mount &&
531 		    fdp->fd_ncdir.ncp == info->old_nch.ncp) {
532 			vprele1 = fdp->fd_cdir;
533 			vref(info->new_vp);
534 			fdp->fd_cdir = info->new_vp;
535 			ncdrop1 = fdp->fd_ncdir;
536 			cache_copy(&info->new_nch, &fdp->fd_ncdir);
537 		}
538 		if (fdp->fd_nrdir.mount == info->old_nch.mount &&
539 		    fdp->fd_nrdir.ncp == info->old_nch.ncp) {
540 			vprele2 = fdp->fd_rdir;
541 			vref(info->new_vp);
542 			fdp->fd_rdir = info->new_vp;
543 			ncdrop2 = fdp->fd_nrdir;
544 			cache_copy(&info->new_nch, &fdp->fd_nrdir);
545 		}
546 		spin_unlock(&fdp->fd_spin);
547 		if (ncdrop1.ncp)
548 			cache_drop(&ncdrop1);
549 		if (ncdrop2.ncp)
550 			cache_drop(&ncdrop2);
551 		if (vprele1)
552 			vrele(vprele1);
553 		if (vprele2)
554 			vrele(vprele2);
555 	}
556 	return(0);
557 }
558 
559 /*
560  * Unmount a file system.
561  *
562  * Note: unmount takes a path to the vnode mounted on as argument,
563  * not special file (as before).
564  *
565  * umount_args(char *path, int flags)
566  *
567  * MPALMOSTSAFE
568  */
569 int
570 sys_unmount(struct unmount_args *uap)
571 {
572 	struct thread *td = curthread;
573 	struct proc *p __debugvar = td->td_proc;
574 	struct mount *mp = NULL;
575 	struct nlookupdata nd;
576 	int error;
577 
578 	KKASSERT(p);
579 	get_mplock();
580 	if (td->td_ucred->cr_prison != NULL) {
581 		error = EPERM;
582 		goto done;
583 	}
584 	if (usermount == 0 && (error = priv_check(td, PRIV_ROOT)))
585 		goto done;
586 
587 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
588 	if (error == 0)
589 		error = nlookup(&nd);
590 	if (error)
591 		goto out;
592 
593 	mp = nd.nl_nch.mount;
594 
595 	/*
596 	 * Only root, or the user that did the original mount is
597 	 * permitted to unmount this filesystem.
598 	 */
599 	if ((mp->mnt_stat.f_owner != td->td_ucred->cr_uid) &&
600 	    (error = priv_check(td, PRIV_ROOT)))
601 		goto out;
602 
603 	/*
604 	 * Don't allow unmounting the root file system.
605 	 */
606 	if (mp->mnt_flag & MNT_ROOTFS) {
607 		error = EINVAL;
608 		goto out;
609 	}
610 
611 	/*
612 	 * Must be the root of the filesystem
613 	 */
614 	if (nd.nl_nch.ncp != mp->mnt_ncmountpt.ncp) {
615 		error = EINVAL;
616 		goto out;
617 	}
618 
619 out:
620 	nlookup_done(&nd);
621 	if (error == 0)
622 		error = dounmount(mp, uap->flags);
623 done:
624 	rel_mplock();
625 	return (error);
626 }
627 
628 /*
629  * Do the actual file system unmount.
630  */
631 static int
632 dounmount_interlock(struct mount *mp)
633 {
634 	if (mp->mnt_kern_flag & MNTK_UNMOUNT)
635 		return (EBUSY);
636 	mp->mnt_kern_flag |= MNTK_UNMOUNT;
637 	return(0);
638 }
639 
640 static int
641 unmount_allproc_cb(struct proc *p, void *arg)
642 {
643 	struct mount *mp;
644 
645 	if (p->p_textnch.ncp == NULL)
646 		return 0;
647 
648 	mp = (struct mount *)arg;
649 	if (p->p_textnch.mount == mp)
650 		cache_drop(&p->p_textnch);
651 
652 	return 0;
653 }
654 
655 int
656 dounmount(struct mount *mp, int flags)
657 {
658 	struct namecache *ncp;
659 	struct nchandle nch;
660 	struct vnode *vp;
661 	int error;
662 	int async_flag;
663 	int lflags;
664 	int freeok = 1;
665 
666 	/*
667 	 * Exclusive access for unmounting purposes
668 	 */
669 	if ((error = mountlist_interlock(dounmount_interlock, mp)) != 0)
670 		return (error);
671 
672 	/*
673 	 * Allow filesystems to detect that a forced unmount is in progress.
674 	 */
675 	if (flags & MNT_FORCE)
676 		mp->mnt_kern_flag |= MNTK_UNMOUNTF;
677 	lflags = LK_EXCLUSIVE | ((flags & MNT_FORCE) ? 0 : LK_NOWAIT);
678 	error = lockmgr(&mp->mnt_lock, lflags);
679 	if (error) {
680 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
681 		if (mp->mnt_kern_flag & MNTK_MWAIT)
682 			wakeup(mp);
683 		return (error);
684 	}
685 
686 	if (mp->mnt_flag & MNT_EXPUBLIC)
687 		vfs_setpublicfs(NULL, NULL, NULL);
688 
689 	vfs_msync(mp, MNT_WAIT);
690 	async_flag = mp->mnt_flag & MNT_ASYNC;
691 	mp->mnt_flag &=~ MNT_ASYNC;
692 
693 	/*
694 	 * If this filesystem isn't aliasing other filesystems,
695 	 * try to invalidate any remaining namecache entries and
696 	 * check the count afterwords.
697 	 */
698 	if ((mp->mnt_kern_flag & MNTK_NCALIASED) == 0) {
699 		cache_lock(&mp->mnt_ncmountpt);
700 		cache_inval(&mp->mnt_ncmountpt, CINV_DESTROY|CINV_CHILDREN);
701 		cache_unlock(&mp->mnt_ncmountpt);
702 
703 		if ((ncp = mp->mnt_ncmountpt.ncp) != NULL &&
704 		    (ncp->nc_refs != 1 || TAILQ_FIRST(&ncp->nc_list))) {
705 			allproc_scan(&unmount_allproc_cb, mp);
706 		}
707 
708 		if ((ncp = mp->mnt_ncmountpt.ncp) != NULL &&
709 		    (ncp->nc_refs != 1 || TAILQ_FIRST(&ncp->nc_list))) {
710 
711 			if ((flags & MNT_FORCE) == 0) {
712 				error = EBUSY;
713 				mount_warning(mp, "Cannot unmount: "
714 						  "%d namecache "
715 						  "references still "
716 						  "present",
717 						  ncp->nc_refs - 1);
718 			} else {
719 				mount_warning(mp, "Forced unmount: "
720 						  "%d namecache "
721 						  "references still "
722 						  "present",
723 						  ncp->nc_refs - 1);
724 				freeok = 0;
725 			}
726 		}
727 	}
728 
729 	/*
730 	 * nchandle records ref the mount structure.  Expect a count of 1
731 	 * (our mount->mnt_ncmountpt).
732 	 */
733 	if (mp->mnt_refs != 1) {
734 		if ((flags & MNT_FORCE) == 0) {
735 			mount_warning(mp, "Cannot unmount: "
736 					  "%d process references still "
737 					  "present", mp->mnt_refs);
738 			error = EBUSY;
739 		} else {
740 			mount_warning(mp, "Forced unmount: "
741 					  "%d process references still "
742 					  "present", mp->mnt_refs);
743 			freeok = 0;
744 		}
745 	}
746 
747 	/*
748 	 * Decomission our special mnt_syncer vnode.  This also stops
749 	 * the vnlru code.  If we are unable to unmount we recommission
750 	 * the vnode.
751 	 */
752 	if (error == 0) {
753 		if ((vp = mp->mnt_syncer) != NULL) {
754 			mp->mnt_syncer = NULL;
755 			vrele(vp);
756 		}
757 		if (((mp->mnt_flag & MNT_RDONLY) ||
758 		     (error = VFS_SYNC(mp, MNT_WAIT)) == 0) ||
759 		    (flags & MNT_FORCE)) {
760 			error = VFS_UNMOUNT(mp, flags);
761 		}
762 	}
763 	if (error) {
764 		if (mp->mnt_syncer == NULL)
765 			vfs_allocate_syncvnode(mp);
766 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
767 		mp->mnt_flag |= async_flag;
768 		lockmgr(&mp->mnt_lock, LK_RELEASE);
769 		if (mp->mnt_kern_flag & MNTK_MWAIT)
770 			wakeup(mp);
771 		return (error);
772 	}
773 	/*
774 	 * Clean up any journals still associated with the mount after
775 	 * filesystem activity has ceased.
776 	 */
777 	journal_remove_all_journals(mp,
778 	    ((flags & MNT_FORCE) ? MC_JOURNAL_STOP_IMM : 0));
779 
780 	mountlist_remove(mp);
781 
782 	/*
783 	 * Remove any installed vnode ops here so the individual VFSs don't
784 	 * have to.
785 	 */
786 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
787 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
788 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
789 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
790 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
791 
792 	if (mp->mnt_ncmountpt.ncp != NULL) {
793 		nch = mp->mnt_ncmountpt;
794 		cache_zero(&mp->mnt_ncmountpt);
795 		cache_clrmountpt(&nch);
796 		cache_drop(&nch);
797 	}
798 	if (mp->mnt_ncmounton.ncp != NULL) {
799 		nch = mp->mnt_ncmounton;
800 		cache_zero(&mp->mnt_ncmounton);
801 		cache_clrmountpt(&nch);
802 		cache_drop(&nch);
803 	}
804 
805 	mp->mnt_vfc->vfc_refcount--;
806 	if (!TAILQ_EMPTY(&mp->mnt_nvnodelist))
807 		panic("unmount: dangling vnode");
808 	lockmgr(&mp->mnt_lock, LK_RELEASE);
809 	if (mp->mnt_kern_flag & MNTK_MWAIT)
810 		wakeup(mp);
811 	if (freeok)
812 		kfree(mp, M_MOUNT);
813 	return (0);
814 }
815 
816 static
817 void
818 mount_warning(struct mount *mp, const char *ctl, ...)
819 {
820 	char *ptr;
821 	char *buf;
822 	__va_list va;
823 
824 	__va_start(va, ctl);
825 	if (cache_fullpath(NULL, &mp->mnt_ncmounton, &ptr, &buf, 0) == 0) {
826 		kprintf("unmount(%s): ", ptr);
827 		kvprintf(ctl, va);
828 		kprintf("\n");
829 		kfree(buf, M_TEMP);
830 	} else {
831 		kprintf("unmount(%p", mp);
832 		if (mp->mnt_ncmounton.ncp && mp->mnt_ncmounton.ncp->nc_name)
833 			kprintf(",%s", mp->mnt_ncmounton.ncp->nc_name);
834 		kprintf("): ");
835 		kvprintf(ctl, va);
836 		kprintf("\n");
837 	}
838 	__va_end(va);
839 }
840 
841 /*
842  * Shim cache_fullpath() to handle the case where a process is chrooted into
843  * a subdirectory of a mount.  In this case if the root mount matches the
844  * process root directory's mount we have to specify the process's root
845  * directory instead of the mount point, because the mount point might
846  * be above the root directory.
847  */
848 static
849 int
850 mount_path(struct proc *p, struct mount *mp, char **rb, char **fb)
851 {
852 	struct nchandle *nch;
853 
854 	if (p && p->p_fd->fd_nrdir.mount == mp)
855 		nch = &p->p_fd->fd_nrdir;
856 	else
857 		nch = &mp->mnt_ncmountpt;
858 	return(cache_fullpath(p, nch, rb, fb, 0));
859 }
860 
861 /*
862  * Sync each mounted filesystem.
863  */
864 
865 #ifdef DEBUG
866 static int syncprt = 0;
867 SYSCTL_INT(_debug, OID_AUTO, syncprt, CTLFLAG_RW, &syncprt, 0, "");
868 #endif /* DEBUG */
869 
870 static int sync_callback(struct mount *mp, void *data);
871 
872 int
873 sys_sync(struct sync_args *uap)
874 {
875 	mountlist_scan(sync_callback, NULL, MNTSCAN_FORWARD);
876 #ifdef DEBUG
877 	/*
878 	 * print out buffer pool stat information on each sync() call.
879 	 */
880 	if (syncprt)
881 		vfs_bufstats();
882 #endif /* DEBUG */
883 	return (0);
884 }
885 
886 static
887 int
888 sync_callback(struct mount *mp, void *data __unused)
889 {
890 	int asyncflag;
891 
892 	if ((mp->mnt_flag & MNT_RDONLY) == 0) {
893 		asyncflag = mp->mnt_flag & MNT_ASYNC;
894 		mp->mnt_flag &= ~MNT_ASYNC;
895 		vfs_msync(mp, MNT_NOWAIT);
896 		VFS_SYNC(mp, MNT_NOWAIT | MNT_LAZY);
897 		mp->mnt_flag |= asyncflag;
898 	}
899 	return(0);
900 }
901 
902 /* XXX PRISON: could be per prison flag */
903 static int prison_quotas;
904 #if 0
905 SYSCTL_INT(_kern_prison, OID_AUTO, quotas, CTLFLAG_RW, &prison_quotas, 0, "");
906 #endif
907 
908 /*
909  *  quotactl_args(char *path, int fcmd, int uid, caddr_t arg)
910  *
911  * Change filesystem quotas.
912  *
913  * MPALMOSTSAFE
914  */
915 int
916 sys_quotactl(struct quotactl_args *uap)
917 {
918 	struct nlookupdata nd;
919 	struct thread *td;
920 	struct mount *mp;
921 	int error;
922 
923 	get_mplock();
924 	td = curthread;
925 	if (td->td_ucred->cr_prison && !prison_quotas) {
926 		error = EPERM;
927 		goto done;
928 	}
929 
930 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
931 	if (error == 0)
932 		error = nlookup(&nd);
933 	if (error == 0) {
934 		mp = nd.nl_nch.mount;
935 		error = VFS_QUOTACTL(mp, uap->cmd, uap->uid,
936 				    uap->arg, nd.nl_cred);
937 	}
938 	nlookup_done(&nd);
939 done:
940 	rel_mplock();
941 	return (error);
942 }
943 
944 /*
945  * mountctl(char *path, int op, int fd, const void *ctl, int ctllen,
946  *		void *buf, int buflen)
947  *
948  * This function operates on a mount point and executes the specified
949  * operation using the specified control data, and possibly returns data.
950  *
951  * The actual number of bytes stored in the result buffer is returned, 0
952  * if none, otherwise an error is returned.
953  *
954  * MPALMOSTSAFE
955  */
956 int
957 sys_mountctl(struct mountctl_args *uap)
958 {
959 	struct thread *td = curthread;
960 	struct proc *p = td->td_proc;
961 	struct file *fp;
962 	void *ctl = NULL;
963 	void *buf = NULL;
964 	char *path = NULL;
965 	int error;
966 
967 	/*
968 	 * Sanity and permissions checks.  We must be root.
969 	 */
970 	KKASSERT(p);
971 	if (td->td_ucred->cr_prison != NULL)
972 		return (EPERM);
973 	if ((uap->op != MOUNTCTL_MOUNTFLAGS) &&
974 	    (error = priv_check(td, PRIV_ROOT)) != 0)
975 		return (error);
976 
977 	/*
978 	 * Argument length checks
979 	 */
980 	if (uap->ctllen < 0 || uap->ctllen > 1024)
981 		return (EINVAL);
982 	if (uap->buflen < 0 || uap->buflen > 16 * 1024)
983 		return (EINVAL);
984 	if (uap->path == NULL)
985 		return (EINVAL);
986 
987 	/*
988 	 * Allocate the necessary buffers and copyin data
989 	 */
990 	path = objcache_get(namei_oc, M_WAITOK);
991 	error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
992 	if (error)
993 		goto done;
994 
995 	if (uap->ctllen) {
996 		ctl = kmalloc(uap->ctllen + 1, M_TEMP, M_WAITOK|M_ZERO);
997 		error = copyin(uap->ctl, ctl, uap->ctllen);
998 		if (error)
999 			goto done;
1000 	}
1001 	if (uap->buflen)
1002 		buf = kmalloc(uap->buflen + 1, M_TEMP, M_WAITOK|M_ZERO);
1003 
1004 	/*
1005 	 * Validate the descriptor
1006 	 */
1007 	if (uap->fd >= 0) {
1008 		fp = holdfp(p->p_fd, uap->fd, -1);
1009 		if (fp == NULL) {
1010 			error = EBADF;
1011 			goto done;
1012 		}
1013 	} else {
1014 		fp = NULL;
1015 	}
1016 
1017 	/*
1018 	 * Execute the internal kernel function and clean up.
1019 	 */
1020 	get_mplock();
1021 	error = kern_mountctl(path, uap->op, fp, ctl, uap->ctllen, buf, uap->buflen, &uap->sysmsg_result);
1022 	rel_mplock();
1023 	if (fp)
1024 		fdrop(fp);
1025 	if (error == 0 && uap->sysmsg_result > 0)
1026 		error = copyout(buf, uap->buf, uap->sysmsg_result);
1027 done:
1028 	if (path)
1029 		objcache_put(namei_oc, path);
1030 	if (ctl)
1031 		kfree(ctl, M_TEMP);
1032 	if (buf)
1033 		kfree(buf, M_TEMP);
1034 	return (error);
1035 }
1036 
1037 /*
1038  * Execute a mount control operation by resolving the path to a mount point
1039  * and calling vop_mountctl().
1040  *
1041  * Use the mount point from the nch instead of the vnode so nullfs mounts
1042  * can properly spike the VOP.
1043  */
1044 int
1045 kern_mountctl(const char *path, int op, struct file *fp,
1046 		const void *ctl, int ctllen,
1047 		void *buf, int buflen, int *res)
1048 {
1049 	struct vnode *vp;
1050 	struct mount *mp;
1051 	struct nlookupdata nd;
1052 	int error;
1053 
1054 	*res = 0;
1055 	vp = NULL;
1056 	error = nlookup_init(&nd, path, UIO_SYSSPACE, NLC_FOLLOW);
1057 	if (error == 0)
1058 		error = nlookup(&nd);
1059 	if (error == 0)
1060 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
1061 	mp = nd.nl_nch.mount;
1062 	nlookup_done(&nd);
1063 	if (error)
1064 		return (error);
1065 	vn_unlock(vp);
1066 
1067 	/*
1068 	 * Must be the root of the filesystem
1069 	 */
1070 	if ((vp->v_flag & (VROOT|VPFSROOT)) == 0) {
1071 		vrele(vp);
1072 		return (EINVAL);
1073 	}
1074 	error = vop_mountctl(mp->mnt_vn_use_ops, vp, op, fp, ctl, ctllen,
1075 			     buf, buflen, res);
1076 	vrele(vp);
1077 	return (error);
1078 }
1079 
1080 int
1081 kern_statfs(struct nlookupdata *nd, struct statfs *buf)
1082 {
1083 	struct thread *td = curthread;
1084 	struct proc *p = td->td_proc;
1085 	struct mount *mp;
1086 	struct statfs *sp;
1087 	char *fullpath, *freepath;
1088 	int error;
1089 
1090 	if ((error = nlookup(nd)) != 0)
1091 		return (error);
1092 	mp = nd->nl_nch.mount;
1093 	sp = &mp->mnt_stat;
1094 	if ((error = VFS_STATFS(mp, sp, nd->nl_cred)) != 0)
1095 		return (error);
1096 
1097 	error = mount_path(p, mp, &fullpath, &freepath);
1098 	if (error)
1099 		return(error);
1100 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1101 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1102 	kfree(freepath, M_TEMP);
1103 
1104 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1105 	bcopy(sp, buf, sizeof(*buf));
1106 	/* Only root should have access to the fsid's. */
1107 	if (priv_check(td, PRIV_ROOT))
1108 		buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
1109 	return (0);
1110 }
1111 
1112 /*
1113  * statfs_args(char *path, struct statfs *buf)
1114  *
1115  * Get filesystem statistics.
1116  */
1117 int
1118 sys_statfs(struct statfs_args *uap)
1119 {
1120 	struct nlookupdata nd;
1121 	struct statfs buf;
1122 	int error;
1123 
1124 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1125 	if (error == 0)
1126 		error = kern_statfs(&nd, &buf);
1127 	nlookup_done(&nd);
1128 	if (error == 0)
1129 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1130 	return (error);
1131 }
1132 
1133 int
1134 kern_fstatfs(int fd, struct statfs *buf)
1135 {
1136 	struct thread *td = curthread;
1137 	struct proc *p = td->td_proc;
1138 	struct file *fp;
1139 	struct mount *mp;
1140 	struct statfs *sp;
1141 	char *fullpath, *freepath;
1142 	int error;
1143 
1144 	KKASSERT(p);
1145 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
1146 		return (error);
1147 
1148 	/*
1149 	 * Try to use mount info from any overlays rather than the
1150 	 * mount info for the underlying vnode, otherwise we will
1151 	 * fail when operating on null-mounted paths inside a chroot.
1152 	 */
1153 	if ((mp = fp->f_nchandle.mount) == NULL)
1154 		mp = ((struct vnode *)fp->f_data)->v_mount;
1155 	if (mp == NULL) {
1156 		error = EBADF;
1157 		goto done;
1158 	}
1159 	if (fp->f_cred == NULL) {
1160 		error = EINVAL;
1161 		goto done;
1162 	}
1163 	sp = &mp->mnt_stat;
1164 	if ((error = VFS_STATFS(mp, sp, fp->f_cred)) != 0)
1165 		goto done;
1166 
1167 	if ((error = mount_path(p, mp, &fullpath, &freepath)) != 0)
1168 		goto done;
1169 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1170 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1171 	kfree(freepath, M_TEMP);
1172 
1173 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1174 	bcopy(sp, buf, sizeof(*buf));
1175 
1176 	/* Only root should have access to the fsid's. */
1177 	if (priv_check(td, PRIV_ROOT))
1178 		buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
1179 	error = 0;
1180 done:
1181 	fdrop(fp);
1182 	return (error);
1183 }
1184 
1185 /*
1186  * fstatfs_args(int fd, struct statfs *buf)
1187  *
1188  * Get filesystem statistics.
1189  */
1190 int
1191 sys_fstatfs(struct fstatfs_args *uap)
1192 {
1193 	struct statfs buf;
1194 	int error;
1195 
1196 	error = kern_fstatfs(uap->fd, &buf);
1197 
1198 	if (error == 0)
1199 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1200 	return (error);
1201 }
1202 
1203 int
1204 kern_statvfs(struct nlookupdata *nd, struct statvfs *buf)
1205 {
1206 	struct mount *mp;
1207 	struct statvfs *sp;
1208 	int error;
1209 
1210 	if ((error = nlookup(nd)) != 0)
1211 		return (error);
1212 	mp = nd->nl_nch.mount;
1213 	sp = &mp->mnt_vstat;
1214 	if ((error = VFS_STATVFS(mp, sp, nd->nl_cred)) != 0)
1215 		return (error);
1216 
1217 	sp->f_flag = 0;
1218 	if (mp->mnt_flag & MNT_RDONLY)
1219 		sp->f_flag |= ST_RDONLY;
1220 	if (mp->mnt_flag & MNT_NOSUID)
1221 		sp->f_flag |= ST_NOSUID;
1222 	bcopy(sp, buf, sizeof(*buf));
1223 	return (0);
1224 }
1225 
1226 /*
1227  * statfs_args(char *path, struct statfs *buf)
1228  *
1229  * Get filesystem statistics.
1230  */
1231 int
1232 sys_statvfs(struct statvfs_args *uap)
1233 {
1234 	struct nlookupdata nd;
1235 	struct statvfs buf;
1236 	int error;
1237 
1238 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1239 	if (error == 0)
1240 		error = kern_statvfs(&nd, &buf);
1241 	nlookup_done(&nd);
1242 	if (error == 0)
1243 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1244 	return (error);
1245 }
1246 
1247 int
1248 kern_fstatvfs(int fd, struct statvfs *buf)
1249 {
1250 	struct thread *td = curthread;
1251 	struct proc *p = td->td_proc;
1252 	struct file *fp;
1253 	struct mount *mp;
1254 	struct statvfs *sp;
1255 	int error;
1256 
1257 	KKASSERT(p);
1258 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
1259 		return (error);
1260 	if ((mp = fp->f_nchandle.mount) == NULL)
1261 		mp = ((struct vnode *)fp->f_data)->v_mount;
1262 	if (mp == NULL) {
1263 		error = EBADF;
1264 		goto done;
1265 	}
1266 	if (fp->f_cred == NULL) {
1267 		error = EINVAL;
1268 		goto done;
1269 	}
1270 	sp = &mp->mnt_vstat;
1271 	if ((error = VFS_STATVFS(mp, sp, fp->f_cred)) != 0)
1272 		goto done;
1273 
1274 	sp->f_flag = 0;
1275 	if (mp->mnt_flag & MNT_RDONLY)
1276 		sp->f_flag |= ST_RDONLY;
1277 	if (mp->mnt_flag & MNT_NOSUID)
1278 		sp->f_flag |= ST_NOSUID;
1279 
1280 	bcopy(sp, buf, sizeof(*buf));
1281 	error = 0;
1282 done:
1283 	fdrop(fp);
1284 	return (error);
1285 }
1286 
1287 /*
1288  * fstatfs_args(int fd, struct statfs *buf)
1289  *
1290  * Get filesystem statistics.
1291  */
1292 int
1293 sys_fstatvfs(struct fstatvfs_args *uap)
1294 {
1295 	struct statvfs buf;
1296 	int error;
1297 
1298 	error = kern_fstatvfs(uap->fd, &buf);
1299 
1300 	if (error == 0)
1301 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1302 	return (error);
1303 }
1304 
1305 /*
1306  * getfsstat_args(struct statfs *buf, long bufsize, int flags)
1307  *
1308  * Get statistics on all filesystems.
1309  */
1310 
1311 struct getfsstat_info {
1312 	struct statfs *sfsp;
1313 	long count;
1314 	long maxcount;
1315 	int error;
1316 	int flags;
1317 	struct thread *td;
1318 };
1319 
1320 static int getfsstat_callback(struct mount *, void *);
1321 
1322 int
1323 sys_getfsstat(struct getfsstat_args *uap)
1324 {
1325 	struct thread *td = curthread;
1326 	struct getfsstat_info info;
1327 
1328 	bzero(&info, sizeof(info));
1329 
1330 	info.maxcount = uap->bufsize / sizeof(struct statfs);
1331 	info.sfsp = uap->buf;
1332 	info.count = 0;
1333 	info.flags = uap->flags;
1334 	info.td = td;
1335 
1336 	mountlist_scan(getfsstat_callback, &info, MNTSCAN_FORWARD);
1337 	if (info.sfsp && info.count > info.maxcount)
1338 		uap->sysmsg_result = info.maxcount;
1339 	else
1340 		uap->sysmsg_result = info.count;
1341 	return (info.error);
1342 }
1343 
1344 static int
1345 getfsstat_callback(struct mount *mp, void *data)
1346 {
1347 	struct getfsstat_info *info = data;
1348 	struct statfs *sp;
1349 	char *freepath;
1350 	char *fullpath;
1351 	int error;
1352 
1353 	if (info->sfsp && info->count < info->maxcount) {
1354 		if (info->td->td_proc &&
1355 		    !chroot_visible_mnt(mp, info->td->td_proc)) {
1356 			return(0);
1357 		}
1358 		sp = &mp->mnt_stat;
1359 
1360 		/*
1361 		 * If MNT_NOWAIT or MNT_LAZY is specified, do not
1362 		 * refresh the fsstat cache. MNT_NOWAIT or MNT_LAZY
1363 		 * overrides MNT_WAIT.
1364 		 */
1365 		if (((info->flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
1366 		    (info->flags & MNT_WAIT)) &&
1367 		    (error = VFS_STATFS(mp, sp, info->td->td_ucred))) {
1368 			return(0);
1369 		}
1370 		sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1371 
1372 		error = mount_path(info->td->td_proc, mp, &fullpath, &freepath);
1373 		if (error) {
1374 			info->error = error;
1375 			return(-1);
1376 		}
1377 		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1378 		strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1379 		kfree(freepath, M_TEMP);
1380 
1381 		error = copyout(sp, info->sfsp, sizeof(*sp));
1382 		if (error) {
1383 			info->error = error;
1384 			return (-1);
1385 		}
1386 		++info->sfsp;
1387 	}
1388 	info->count++;
1389 	return(0);
1390 }
1391 
1392 /*
1393  * getvfsstat_args(struct statfs *buf, struct statvfs *vbuf,
1394 		   long bufsize, int flags)
1395  *
1396  * Get statistics on all filesystems.
1397  */
1398 
1399 struct getvfsstat_info {
1400 	struct statfs *sfsp;
1401 	struct statvfs *vsfsp;
1402 	long count;
1403 	long maxcount;
1404 	int error;
1405 	int flags;
1406 	struct thread *td;
1407 };
1408 
1409 static int getvfsstat_callback(struct mount *, void *);
1410 
1411 int
1412 sys_getvfsstat(struct getvfsstat_args *uap)
1413 {
1414 	struct thread *td = curthread;
1415 	struct getvfsstat_info info;
1416 
1417 	bzero(&info, sizeof(info));
1418 
1419 	info.maxcount = uap->vbufsize / sizeof(struct statvfs);
1420 	info.sfsp = uap->buf;
1421 	info.vsfsp = uap->vbuf;
1422 	info.count = 0;
1423 	info.flags = uap->flags;
1424 	info.td = td;
1425 
1426 	mountlist_scan(getvfsstat_callback, &info, MNTSCAN_FORWARD);
1427 	if (info.vsfsp && info.count > info.maxcount)
1428 		uap->sysmsg_result = info.maxcount;
1429 	else
1430 		uap->sysmsg_result = info.count;
1431 	return (info.error);
1432 }
1433 
1434 static int
1435 getvfsstat_callback(struct mount *mp, void *data)
1436 {
1437 	struct getvfsstat_info *info = data;
1438 	struct statfs *sp;
1439 	struct statvfs *vsp;
1440 	char *freepath;
1441 	char *fullpath;
1442 	int error;
1443 
1444 	if (info->vsfsp && info->count < info->maxcount) {
1445 		if (info->td->td_proc &&
1446 		    !chroot_visible_mnt(mp, info->td->td_proc)) {
1447 			return(0);
1448 		}
1449 		sp = &mp->mnt_stat;
1450 		vsp = &mp->mnt_vstat;
1451 
1452 		/*
1453 		 * If MNT_NOWAIT or MNT_LAZY is specified, do not
1454 		 * refresh the fsstat cache. MNT_NOWAIT or MNT_LAZY
1455 		 * overrides MNT_WAIT.
1456 		 */
1457 		if (((info->flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
1458 		    (info->flags & MNT_WAIT)) &&
1459 		    (error = VFS_STATFS(mp, sp, info->td->td_ucred))) {
1460 			return(0);
1461 		}
1462 		sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1463 
1464 		if (((info->flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
1465 		    (info->flags & MNT_WAIT)) &&
1466 		    (error = VFS_STATVFS(mp, vsp, info->td->td_ucred))) {
1467 			return(0);
1468 		}
1469 		vsp->f_flag = 0;
1470 		if (mp->mnt_flag & MNT_RDONLY)
1471 			vsp->f_flag |= ST_RDONLY;
1472 		if (mp->mnt_flag & MNT_NOSUID)
1473 			vsp->f_flag |= ST_NOSUID;
1474 
1475 		error = mount_path(info->td->td_proc, mp, &fullpath, &freepath);
1476 		if (error) {
1477 			info->error = error;
1478 			return(-1);
1479 		}
1480 		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1481 		strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1482 		kfree(freepath, M_TEMP);
1483 
1484 		error = copyout(sp, info->sfsp, sizeof(*sp));
1485 		if (error == 0)
1486 			error = copyout(vsp, info->vsfsp, sizeof(*vsp));
1487 		if (error) {
1488 			info->error = error;
1489 			return (-1);
1490 		}
1491 		++info->sfsp;
1492 		++info->vsfsp;
1493 	}
1494 	info->count++;
1495 	return(0);
1496 }
1497 
1498 
1499 /*
1500  * fchdir_args(int fd)
1501  *
1502  * Change current working directory to a given file descriptor.
1503  */
1504 int
1505 sys_fchdir(struct fchdir_args *uap)
1506 {
1507 	struct thread *td = curthread;
1508 	struct proc *p = td->td_proc;
1509 	struct filedesc *fdp = p->p_fd;
1510 	struct vnode *vp, *ovp;
1511 	struct mount *mp;
1512 	struct file *fp;
1513 	struct nchandle nch, onch, tnch;
1514 	int error;
1515 
1516 	if ((error = holdvnode(fdp, uap->fd, &fp)) != 0)
1517 		return (error);
1518 	lwkt_gettoken(&p->p_token);
1519 	vp = (struct vnode *)fp->f_data;
1520 	vref(vp);
1521 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1522 	if (fp->f_nchandle.ncp == NULL)
1523 		error = ENOTDIR;
1524 	else
1525 		error = checkvp_chdir(vp, td);
1526 	if (error) {
1527 		vput(vp);
1528 		goto done;
1529 	}
1530 	cache_copy(&fp->f_nchandle, &nch);
1531 
1532 	/*
1533 	 * If the ncp has become a mount point, traverse through
1534 	 * the mount point.
1535 	 */
1536 
1537 	while (!error && (nch.ncp->nc_flag & NCF_ISMOUNTPT) &&
1538 	       (mp = cache_findmount(&nch)) != NULL
1539 	) {
1540 		error = nlookup_mp(mp, &tnch);
1541 		if (error == 0) {
1542 			cache_unlock(&tnch);	/* leave ref intact */
1543 			vput(vp);
1544 			vp = tnch.ncp->nc_vp;
1545 			error = vget(vp, LK_SHARED);
1546 			KKASSERT(error == 0);
1547 			cache_drop(&nch);
1548 			nch = tnch;
1549 		}
1550 		cache_dropmount(mp);
1551 	}
1552 	if (error == 0) {
1553 		ovp = fdp->fd_cdir;
1554 		onch = fdp->fd_ncdir;
1555 		vn_unlock(vp);		/* leave ref intact */
1556 		fdp->fd_cdir = vp;
1557 		fdp->fd_ncdir = nch;
1558 		cache_drop(&onch);
1559 		vrele(ovp);
1560 	} else {
1561 		cache_drop(&nch);
1562 		vput(vp);
1563 	}
1564 	fdrop(fp);
1565 done:
1566 	lwkt_reltoken(&p->p_token);
1567 	return (error);
1568 }
1569 
1570 int
1571 kern_chdir(struct nlookupdata *nd)
1572 {
1573 	struct thread *td = curthread;
1574 	struct proc *p = td->td_proc;
1575 	struct filedesc *fdp = p->p_fd;
1576 	struct vnode *vp, *ovp;
1577 	struct nchandle onch;
1578 	int error;
1579 
1580 	if ((error = nlookup(nd)) != 0)
1581 		return (error);
1582 	if ((vp = nd->nl_nch.ncp->nc_vp) == NULL)
1583 		return (ENOENT);
1584 	if ((error = vget(vp, LK_SHARED)) != 0)
1585 		return (error);
1586 
1587 	lwkt_gettoken(&p->p_token);
1588 	error = checkvp_chdir(vp, td);
1589 	vn_unlock(vp);
1590 	if (error == 0) {
1591 		ovp = fdp->fd_cdir;
1592 		onch = fdp->fd_ncdir;
1593 		cache_unlock(&nd->nl_nch);	/* leave reference intact */
1594 		fdp->fd_ncdir = nd->nl_nch;
1595 		fdp->fd_cdir = vp;
1596 		cache_drop(&onch);
1597 		vrele(ovp);
1598 		cache_zero(&nd->nl_nch);
1599 	} else {
1600 		vrele(vp);
1601 	}
1602 	lwkt_reltoken(&p->p_token);
1603 	return (error);
1604 }
1605 
1606 /*
1607  * chdir_args(char *path)
1608  *
1609  * Change current working directory (``.'').
1610  */
1611 int
1612 sys_chdir(struct chdir_args *uap)
1613 {
1614 	struct nlookupdata nd;
1615 	int error;
1616 
1617 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1618 	if (error == 0)
1619 		error = kern_chdir(&nd);
1620 	nlookup_done(&nd);
1621 	return (error);
1622 }
1623 
1624 /*
1625  * Helper function for raised chroot(2) security function:  Refuse if
1626  * any filedescriptors are open directories.
1627  */
1628 static int
1629 chroot_refuse_vdir_fds(struct filedesc *fdp)
1630 {
1631 	struct vnode *vp;
1632 	struct file *fp;
1633 	int error;
1634 	int fd;
1635 
1636 	for (fd = 0; fd < fdp->fd_nfiles ; fd++) {
1637 		if ((error = holdvnode(fdp, fd, &fp)) != 0)
1638 			continue;
1639 		vp = (struct vnode *)fp->f_data;
1640 		if (vp->v_type != VDIR) {
1641 			fdrop(fp);
1642 			continue;
1643 		}
1644 		fdrop(fp);
1645 		return(EPERM);
1646 	}
1647 	return (0);
1648 }
1649 
1650 /*
1651  * This sysctl determines if we will allow a process to chroot(2) if it
1652  * has a directory open:
1653  *	0: disallowed for all processes.
1654  *	1: allowed for processes that were not already chroot(2)'ed.
1655  *	2: allowed for all processes.
1656  */
1657 
1658 static int chroot_allow_open_directories = 1;
1659 
1660 SYSCTL_INT(_kern, OID_AUTO, chroot_allow_open_directories, CTLFLAG_RW,
1661      &chroot_allow_open_directories, 0, "");
1662 
1663 /*
1664  * chroot to the specified namecache entry.  We obtain the vp from the
1665  * namecache data.  The passed ncp must be locked and referenced and will
1666  * remain locked and referenced on return.
1667  */
1668 int
1669 kern_chroot(struct nchandle *nch)
1670 {
1671 	struct thread *td = curthread;
1672 	struct proc *p = td->td_proc;
1673 	struct filedesc *fdp = p->p_fd;
1674 	struct vnode *vp;
1675 	int error;
1676 
1677 	/*
1678 	 * Only privileged user can chroot
1679 	 */
1680 	error = priv_check_cred(td->td_ucred, PRIV_VFS_CHROOT, 0);
1681 	if (error)
1682 		return (error);
1683 
1684 	/*
1685 	 * Disallow open directory descriptors (fchdir() breakouts).
1686 	 */
1687 	if (chroot_allow_open_directories == 0 ||
1688 	   (chroot_allow_open_directories == 1 && fdp->fd_rdir != rootvnode)) {
1689 		if ((error = chroot_refuse_vdir_fds(fdp)) != 0)
1690 			return (error);
1691 	}
1692 	if ((vp = nch->ncp->nc_vp) == NULL)
1693 		return (ENOENT);
1694 
1695 	if ((error = vget(vp, LK_SHARED)) != 0)
1696 		return (error);
1697 
1698 	/*
1699 	 * Check the validity of vp as a directory to change to and
1700 	 * associate it with rdir/jdir.
1701 	 */
1702 	error = checkvp_chdir(vp, td);
1703 	vn_unlock(vp);			/* leave reference intact */
1704 	if (error == 0) {
1705 		vrele(fdp->fd_rdir);
1706 		fdp->fd_rdir = vp;	/* reference inherited by fd_rdir */
1707 		cache_drop(&fdp->fd_nrdir);
1708 		cache_copy(nch, &fdp->fd_nrdir);
1709 		if (fdp->fd_jdir == NULL) {
1710 			fdp->fd_jdir = vp;
1711 			vref(fdp->fd_jdir);
1712 			cache_copy(nch, &fdp->fd_njdir);
1713 		}
1714 	} else {
1715 		vrele(vp);
1716 	}
1717 	return (error);
1718 }
1719 
1720 /*
1721  * chroot_args(char *path)
1722  *
1723  * Change notion of root (``/'') directory.
1724  */
1725 int
1726 sys_chroot(struct chroot_args *uap)
1727 {
1728 	struct thread *td __debugvar = curthread;
1729 	struct nlookupdata nd;
1730 	int error;
1731 
1732 	KKASSERT(td->td_proc);
1733 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1734 	if (error == 0) {
1735 		nd.nl_flags |= NLC_EXEC;
1736 		error = nlookup(&nd);
1737 		if (error == 0)
1738 			error = kern_chroot(&nd.nl_nch);
1739 	}
1740 	nlookup_done(&nd);
1741 	return(error);
1742 }
1743 
1744 int
1745 sys_chroot_kernel(struct chroot_kernel_args *uap)
1746 {
1747 	struct thread *td = curthread;
1748 	struct nlookupdata nd;
1749 	struct nchandle *nch;
1750 	struct vnode *vp;
1751 	int error;
1752 
1753 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1754 	if (error)
1755 		goto error_nond;
1756 
1757 	error = nlookup(&nd);
1758 	if (error)
1759 		goto error_out;
1760 
1761 	nch = &nd.nl_nch;
1762 
1763 	error = priv_check_cred(td->td_ucred, PRIV_VFS_CHROOT, 0);
1764 	if (error)
1765 		goto error_out;
1766 
1767 	if ((vp = nch->ncp->nc_vp) == NULL) {
1768 		error = ENOENT;
1769 		goto error_out;
1770 	}
1771 
1772 	if ((error = cache_vref(nch, nd.nl_cred, &vp)) != 0)
1773 		goto error_out;
1774 
1775 	kprintf("chroot_kernel: set new rootnch/rootvnode to %s\n", uap->path);
1776 	get_mplock();
1777 	vfs_cache_setroot(vp, cache_hold(nch));
1778 	rel_mplock();
1779 
1780 error_out:
1781 	nlookup_done(&nd);
1782 error_nond:
1783 	return(error);
1784 }
1785 
1786 /*
1787  * Common routine for chroot and chdir.  Given a locked, referenced vnode,
1788  * determine whether it is legal to chdir to the vnode.  The vnode's state
1789  * is not changed by this call.
1790  */
1791 int
1792 checkvp_chdir(struct vnode *vp, struct thread *td)
1793 {
1794 	int error;
1795 
1796 	if (vp->v_type != VDIR)
1797 		error = ENOTDIR;
1798 	else
1799 		error = VOP_EACCESS(vp, VEXEC, td->td_ucred);
1800 	return (error);
1801 }
1802 
1803 int
1804 kern_open(struct nlookupdata *nd, int oflags, int mode, int *res)
1805 {
1806 	struct thread *td = curthread;
1807 	struct proc *p = td->td_proc;
1808 	struct lwp *lp = td->td_lwp;
1809 	struct filedesc *fdp = p->p_fd;
1810 	int cmode, flags;
1811 	struct file *nfp;
1812 	struct file *fp;
1813 	struct vnode *vp;
1814 	int type, indx, error;
1815 	struct flock lf;
1816 
1817 	if ((oflags & O_ACCMODE) == O_ACCMODE)
1818 		return (EINVAL);
1819 	flags = FFLAGS(oflags);
1820 	error = falloc(lp, &nfp, NULL);
1821 	if (error)
1822 		return (error);
1823 	fp = nfp;
1824 	cmode = ((mode &~ fdp->fd_cmask) & ALLPERMS) & ~S_ISTXT;
1825 
1826 	/*
1827 	 * XXX p_dupfd is a real mess.  It allows a device to return a
1828 	 * file descriptor to be duplicated rather then doing the open
1829 	 * itself.
1830 	 */
1831 	lp->lwp_dupfd = -1;
1832 
1833 	/*
1834 	 * Call vn_open() to do the lookup and assign the vnode to the
1835 	 * file pointer.  vn_open() does not change the ref count on fp
1836 	 * and the vnode, on success, will be inherited by the file pointer
1837 	 * and unlocked.
1838 	 */
1839 	nd->nl_flags |= NLC_LOCKVP;
1840 	error = vn_open(nd, fp, flags, cmode);
1841 	nlookup_done(nd);
1842 	if (error) {
1843 		/*
1844 		 * handle special fdopen() case.  bleh.  dupfdopen() is
1845 		 * responsible for dropping the old contents of ofiles[indx]
1846 		 * if it succeeds.
1847 		 *
1848 		 * Note that fsetfd() will add a ref to fp which represents
1849 		 * the fd_files[] assignment.  We must still drop our
1850 		 * reference.
1851 		 */
1852 		if ((error == ENODEV || error == ENXIO) && lp->lwp_dupfd >= 0) {
1853 			if (fdalloc(p, 0, &indx) == 0) {
1854 				error = dupfdopen(fdp, indx, lp->lwp_dupfd, flags, error);
1855 				if (error == 0) {
1856 					*res = indx;
1857 					fdrop(fp);	/* our ref */
1858 					return (0);
1859 				}
1860 				fsetfd(fdp, NULL, indx);
1861 			}
1862 		}
1863 		fdrop(fp);	/* our ref */
1864 		if (error == ERESTART)
1865 			error = EINTR;
1866 		return (error);
1867 	}
1868 
1869 	/*
1870 	 * ref the vnode for ourselves so it can't be ripped out from under
1871 	 * is.  XXX need an ND flag to request that the vnode be returned
1872 	 * anyway.
1873 	 *
1874 	 * Reserve a file descriptor but do not assign it until the open
1875 	 * succeeds.
1876 	 */
1877 	vp = (struct vnode *)fp->f_data;
1878 	vref(vp);
1879 	if ((error = fdalloc(p, 0, &indx)) != 0) {
1880 		fdrop(fp);
1881 		vrele(vp);
1882 		return (error);
1883 	}
1884 
1885 	/*
1886 	 * If no error occurs the vp will have been assigned to the file
1887 	 * pointer.
1888 	 */
1889 	lp->lwp_dupfd = 0;
1890 
1891 	if (flags & (O_EXLOCK | O_SHLOCK)) {
1892 		lf.l_whence = SEEK_SET;
1893 		lf.l_start = 0;
1894 		lf.l_len = 0;
1895 		if (flags & O_EXLOCK)
1896 			lf.l_type = F_WRLCK;
1897 		else
1898 			lf.l_type = F_RDLCK;
1899 		if (flags & FNONBLOCK)
1900 			type = 0;
1901 		else
1902 			type = F_WAIT;
1903 
1904 		if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0) {
1905 			/*
1906 			 * lock request failed.  Clean up the reserved
1907 			 * descriptor.
1908 			 */
1909 			vrele(vp);
1910 			fsetfd(fdp, NULL, indx);
1911 			fdrop(fp);
1912 			return (error);
1913 		}
1914 		fp->f_flag |= FHASLOCK;
1915 	}
1916 #if 0
1917 	/*
1918 	 * Assert that all regular file vnodes were created with a object.
1919 	 */
1920 	KASSERT(vp->v_type != VREG || vp->v_object != NULL,
1921 		("open: regular file has no backing object after vn_open"));
1922 #endif
1923 
1924 	vrele(vp);
1925 
1926 	/*
1927 	 * release our private reference, leaving the one associated with the
1928 	 * descriptor table intact.
1929 	 */
1930 	fsetfd(fdp, fp, indx);
1931 	fdrop(fp);
1932 	*res = indx;
1933 	return (0);
1934 }
1935 
1936 /*
1937  * open_args(char *path, int flags, int mode)
1938  *
1939  * Check permissions, allocate an open file structure,
1940  * and call the device open routine if any.
1941  */
1942 int
1943 sys_open(struct open_args *uap)
1944 {
1945 	struct nlookupdata nd;
1946 	int error;
1947 
1948 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
1949 	if (error == 0) {
1950 		error = kern_open(&nd, uap->flags,
1951 				    uap->mode, &uap->sysmsg_result);
1952 	}
1953 	nlookup_done(&nd);
1954 	return (error);
1955 }
1956 
1957 /*
1958  * openat_args(int fd, char *path, int flags, int mode)
1959  */
1960 int
1961 sys_openat(struct openat_args *uap)
1962 {
1963 	struct nlookupdata nd;
1964 	int error;
1965 	struct file *fp;
1966 
1967 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
1968 	if (error == 0) {
1969 		error = kern_open(&nd, uap->flags, uap->mode,
1970 					&uap->sysmsg_result);
1971 	}
1972 	nlookup_done_at(&nd, fp);
1973 	return (error);
1974 }
1975 
1976 int
1977 kern_mknod(struct nlookupdata *nd, int mode, int rmajor, int rminor)
1978 {
1979 	struct thread *td = curthread;
1980 	struct proc *p = td->td_proc;
1981 	struct vnode *vp;
1982 	struct vattr vattr;
1983 	int error;
1984 	int whiteout = 0;
1985 
1986 	KKASSERT(p);
1987 
1988 	VATTR_NULL(&vattr);
1989 	vattr.va_mode = (mode & ALLPERMS) &~ p->p_fd->fd_cmask;
1990 	vattr.va_rmajor = rmajor;
1991 	vattr.va_rminor = rminor;
1992 
1993 	switch (mode & S_IFMT) {
1994 	case S_IFMT:	/* used by badsect to flag bad sectors */
1995 		error = priv_check_cred(td->td_ucred, PRIV_VFS_MKNOD_BAD, 0);
1996 		vattr.va_type = VBAD;
1997 		break;
1998 	case S_IFCHR:
1999 		error = priv_check(td, PRIV_VFS_MKNOD_DEV);
2000 		vattr.va_type = VCHR;
2001 		break;
2002 	case S_IFBLK:
2003 		error = priv_check(td, PRIV_VFS_MKNOD_DEV);
2004 		vattr.va_type = VBLK;
2005 		break;
2006 	case S_IFWHT:
2007 		error = priv_check_cred(td->td_ucred, PRIV_VFS_MKNOD_WHT, 0);
2008 		whiteout = 1;
2009 		break;
2010 	case S_IFDIR:	/* special directories support for HAMMER */
2011 		error = priv_check_cred(td->td_ucred, PRIV_VFS_MKNOD_DIR, 0);
2012 		vattr.va_type = VDIR;
2013 		break;
2014 	default:
2015 		error = EINVAL;
2016 		break;
2017 	}
2018 
2019 	if (error)
2020 		return (error);
2021 
2022 	bwillinode(1);
2023 	nd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2024 	if ((error = nlookup(nd)) != 0)
2025 		return (error);
2026 	if (nd->nl_nch.ncp->nc_vp)
2027 		return (EEXIST);
2028 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2029 		return (error);
2030 
2031 	if (whiteout) {
2032 		error = VOP_NWHITEOUT(&nd->nl_nch, nd->nl_dvp,
2033 				      nd->nl_cred, NAMEI_CREATE);
2034 	} else {
2035 		vp = NULL;
2036 		error = VOP_NMKNOD(&nd->nl_nch, nd->nl_dvp,
2037 				   &vp, nd->nl_cred, &vattr);
2038 		if (error == 0)
2039 			vput(vp);
2040 	}
2041 	return (error);
2042 }
2043 
2044 /*
2045  * mknod_args(char *path, int mode, int dev)
2046  *
2047  * Create a special file.
2048  */
2049 int
2050 sys_mknod(struct mknod_args *uap)
2051 {
2052 	struct nlookupdata nd;
2053 	int error;
2054 
2055 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2056 	if (error == 0) {
2057 		error = kern_mknod(&nd, uap->mode,
2058 				   umajor(uap->dev), uminor(uap->dev));
2059 	}
2060 	nlookup_done(&nd);
2061 	return (error);
2062 }
2063 
2064 /*
2065  * mknodat_args(int fd, char *path, mode_t mode, dev_t dev)
2066  *
2067  * Create a special file.  The path is relative to the directory associated
2068  * with fd.
2069  */
2070 int
2071 sys_mknodat(struct mknodat_args *uap)
2072 {
2073 	struct nlookupdata nd;
2074 	struct file *fp;
2075 	int error;
2076 
2077 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2078 	if (error == 0) {
2079 		error = kern_mknod(&nd, uap->mode,
2080 				   umajor(uap->dev), uminor(uap->dev));
2081 	}
2082 	nlookup_done_at(&nd, fp);
2083 	return (error);
2084 }
2085 
2086 int
2087 kern_mkfifo(struct nlookupdata *nd, int mode)
2088 {
2089 	struct thread *td = curthread;
2090 	struct proc *p = td->td_proc;
2091 	struct vattr vattr;
2092 	struct vnode *vp;
2093 	int error;
2094 
2095 	bwillinode(1);
2096 
2097 	nd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2098 	if ((error = nlookup(nd)) != 0)
2099 		return (error);
2100 	if (nd->nl_nch.ncp->nc_vp)
2101 		return (EEXIST);
2102 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2103 		return (error);
2104 
2105 	VATTR_NULL(&vattr);
2106 	vattr.va_type = VFIFO;
2107 	vattr.va_mode = (mode & ALLPERMS) &~ p->p_fd->fd_cmask;
2108 	vp = NULL;
2109 	error = VOP_NMKNOD(&nd->nl_nch, nd->nl_dvp, &vp, nd->nl_cred, &vattr);
2110 	if (error == 0)
2111 		vput(vp);
2112 	return (error);
2113 }
2114 
2115 /*
2116  * mkfifo_args(char *path, int mode)
2117  *
2118  * Create a named pipe.
2119  */
2120 int
2121 sys_mkfifo(struct mkfifo_args *uap)
2122 {
2123 	struct nlookupdata nd;
2124 	int error;
2125 
2126 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2127 	if (error == 0)
2128 		error = kern_mkfifo(&nd, uap->mode);
2129 	nlookup_done(&nd);
2130 	return (error);
2131 }
2132 
2133 /*
2134  * mkfifoat_args(int fd, char *path, mode_t mode)
2135  *
2136  * Create a named pipe.  The path is relative to the directory associated
2137  * with fd.
2138  */
2139 int
2140 sys_mkfifoat(struct mkfifoat_args *uap)
2141 {
2142 	struct nlookupdata nd;
2143 	struct file *fp;
2144 	int error;
2145 
2146 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2147 	if (error == 0)
2148 		error = kern_mkfifo(&nd, uap->mode);
2149 	nlookup_done_at(&nd, fp);
2150 	return (error);
2151 }
2152 
2153 static int hardlink_check_uid = 0;
2154 SYSCTL_INT(_security, OID_AUTO, hardlink_check_uid, CTLFLAG_RW,
2155     &hardlink_check_uid, 0,
2156     "Unprivileged processes cannot create hard links to files owned by other "
2157     "users");
2158 static int hardlink_check_gid = 0;
2159 SYSCTL_INT(_security, OID_AUTO, hardlink_check_gid, CTLFLAG_RW,
2160     &hardlink_check_gid, 0,
2161     "Unprivileged processes cannot create hard links to files owned by other "
2162     "groups");
2163 
2164 static int
2165 can_hardlink(struct vnode *vp, struct thread *td, struct ucred *cred)
2166 {
2167 	struct vattr va;
2168 	int error;
2169 
2170 	/*
2171 	 * Shortcut if disabled
2172 	 */
2173 	if (hardlink_check_uid == 0 && hardlink_check_gid == 0)
2174 		return (0);
2175 
2176 	/*
2177 	 * Privileged user can always hardlink
2178 	 */
2179 	if (priv_check_cred(cred, PRIV_VFS_LINK, 0) == 0)
2180 		return (0);
2181 
2182 	/*
2183 	 * Otherwise only if the originating file is owned by the
2184 	 * same user or group.  Note that any group is allowed if
2185 	 * the file is owned by the caller.
2186 	 */
2187 	error = VOP_GETATTR(vp, &va);
2188 	if (error != 0)
2189 		return (error);
2190 
2191 	if (hardlink_check_uid) {
2192 		if (cred->cr_uid != va.va_uid)
2193 			return (EPERM);
2194 	}
2195 
2196 	if (hardlink_check_gid) {
2197 		if (cred->cr_uid != va.va_uid && !groupmember(va.va_gid, cred))
2198 			return (EPERM);
2199 	}
2200 
2201 	return (0);
2202 }
2203 
2204 int
2205 kern_link(struct nlookupdata *nd, struct nlookupdata *linknd)
2206 {
2207 	struct thread *td = curthread;
2208 	struct vnode *vp;
2209 	int error;
2210 
2211 	/*
2212 	 * Lookup the source and obtained a locked vnode.
2213 	 *
2214 	 * You may only hardlink a file which you have write permission
2215 	 * on or which you own.
2216 	 *
2217 	 * XXX relookup on vget failure / race ?
2218 	 */
2219 	bwillinode(1);
2220 	nd->nl_flags |= NLC_WRITE | NLC_OWN | NLC_HLINK;
2221 	if ((error = nlookup(nd)) != 0)
2222 		return (error);
2223 	vp = nd->nl_nch.ncp->nc_vp;
2224 	KKASSERT(vp != NULL);
2225 	if (vp->v_type == VDIR)
2226 		return (EPERM);		/* POSIX */
2227 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2228 		return (error);
2229 	if ((error = vget(vp, LK_EXCLUSIVE)) != 0)
2230 		return (error);
2231 
2232 	/*
2233 	 * Unlock the source so we can lookup the target without deadlocking
2234 	 * (XXX vp is locked already, possible other deadlock?).  The target
2235 	 * must not exist.
2236 	 */
2237 	KKASSERT(nd->nl_flags & NLC_NCPISLOCKED);
2238 	nd->nl_flags &= ~NLC_NCPISLOCKED;
2239 	cache_unlock(&nd->nl_nch);
2240 	vn_unlock(vp);
2241 
2242 	linknd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2243 	if ((error = nlookup(linknd)) != 0) {
2244 		vrele(vp);
2245 		return (error);
2246 	}
2247 	if (linknd->nl_nch.ncp->nc_vp) {
2248 		vrele(vp);
2249 		return (EEXIST);
2250 	}
2251 	if ((error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY)) != 0) {
2252 		vrele(vp);
2253 		return (error);
2254 	}
2255 
2256 	/*
2257 	 * Finally run the new API VOP.
2258 	 */
2259 	error = can_hardlink(vp, td, td->td_ucred);
2260 	if (error == 0) {
2261 		error = VOP_NLINK(&linknd->nl_nch, linknd->nl_dvp,
2262 				  vp, linknd->nl_cred);
2263 	}
2264 	vput(vp);
2265 	return (error);
2266 }
2267 
2268 /*
2269  * link_args(char *path, char *link)
2270  *
2271  * Make a hard file link.
2272  */
2273 int
2274 sys_link(struct link_args *uap)
2275 {
2276 	struct nlookupdata nd, linknd;
2277 	int error;
2278 
2279 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2280 	if (error == 0) {
2281 		error = nlookup_init(&linknd, uap->link, UIO_USERSPACE, 0);
2282 		if (error == 0)
2283 			error = kern_link(&nd, &linknd);
2284 		nlookup_done(&linknd);
2285 	}
2286 	nlookup_done(&nd);
2287 	return (error);
2288 }
2289 
2290 int
2291 kern_symlink(struct nlookupdata *nd, char *path, int mode)
2292 {
2293 	struct vattr vattr;
2294 	struct vnode *vp;
2295 	struct vnode *dvp;
2296 	int error;
2297 
2298 	bwillinode(1);
2299 	nd->nl_flags |= NLC_CREATE | NLC_REFDVP;
2300 	if ((error = nlookup(nd)) != 0)
2301 		return (error);
2302 	if (nd->nl_nch.ncp->nc_vp)
2303 		return (EEXIST);
2304 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2305 		return (error);
2306 	dvp = nd->nl_dvp;
2307 	VATTR_NULL(&vattr);
2308 	vattr.va_mode = mode;
2309 	error = VOP_NSYMLINK(&nd->nl_nch, dvp, &vp, nd->nl_cred, &vattr, path);
2310 	if (error == 0)
2311 		vput(vp);
2312 	return (error);
2313 }
2314 
2315 /*
2316  * symlink(char *path, char *link)
2317  *
2318  * Make a symbolic link.
2319  */
2320 int
2321 sys_symlink(struct symlink_args *uap)
2322 {
2323 	struct thread *td = curthread;
2324 	struct nlookupdata nd;
2325 	char *path;
2326 	int error;
2327 	int mode;
2328 
2329 	path = objcache_get(namei_oc, M_WAITOK);
2330 	error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
2331 	if (error == 0) {
2332 		error = nlookup_init(&nd, uap->link, UIO_USERSPACE, 0);
2333 		if (error == 0) {
2334 			mode = ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask;
2335 			error = kern_symlink(&nd, path, mode);
2336 		}
2337 		nlookup_done(&nd);
2338 	}
2339 	objcache_put(namei_oc, path);
2340 	return (error);
2341 }
2342 
2343 /*
2344  * symlinkat_args(char *path1, int fd, char *path2)
2345  *
2346  * Make a symbolic link.  The path2 argument is relative to the directory
2347  * associated with fd.
2348  */
2349 int
2350 sys_symlinkat(struct symlinkat_args *uap)
2351 {
2352 	struct thread *td = curthread;
2353 	struct nlookupdata nd;
2354 	struct file *fp;
2355 	char *path1;
2356 	int error;
2357 	int mode;
2358 
2359 	path1 = objcache_get(namei_oc, M_WAITOK);
2360 	error = copyinstr(uap->path1, path1, MAXPATHLEN, NULL);
2361 	if (error == 0) {
2362 		error = nlookup_init_at(&nd, &fp, uap->fd, uap->path2,
2363 		    UIO_USERSPACE, 0);
2364 		if (error == 0) {
2365 			mode = ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask;
2366 			error = kern_symlink(&nd, path1, mode);
2367 		}
2368 		nlookup_done_at(&nd, fp);
2369 	}
2370 	objcache_put(namei_oc, path1);
2371 	return (error);
2372 }
2373 
2374 /*
2375  * undelete_args(char *path)
2376  *
2377  * Delete a whiteout from the filesystem.
2378  */
2379 int
2380 sys_undelete(struct undelete_args *uap)
2381 {
2382 	struct nlookupdata nd;
2383 	int error;
2384 
2385 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2386 	bwillinode(1);
2387 	nd.nl_flags |= NLC_DELETE | NLC_REFDVP;
2388 	if (error == 0)
2389 		error = nlookup(&nd);
2390 	if (error == 0)
2391 		error = ncp_writechk(&nd.nl_nch);
2392 	if (error == 0) {
2393 		error = VOP_NWHITEOUT(&nd.nl_nch, nd.nl_dvp, nd.nl_cred,
2394 				      NAMEI_DELETE);
2395 	}
2396 	nlookup_done(&nd);
2397 	return (error);
2398 }
2399 
2400 int
2401 kern_unlink(struct nlookupdata *nd)
2402 {
2403 	int error;
2404 
2405 	bwillinode(1);
2406 	nd->nl_flags |= NLC_DELETE | NLC_REFDVP;
2407 	if ((error = nlookup(nd)) != 0)
2408 		return (error);
2409 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2410 		return (error);
2411 	error = VOP_NREMOVE(&nd->nl_nch, nd->nl_dvp, nd->nl_cred);
2412 	return (error);
2413 }
2414 
2415 /*
2416  * unlink_args(char *path)
2417  *
2418  * Delete a name from the filesystem.
2419  */
2420 int
2421 sys_unlink(struct unlink_args *uap)
2422 {
2423 	struct nlookupdata nd;
2424 	int error;
2425 
2426 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2427 	if (error == 0)
2428 		error = kern_unlink(&nd);
2429 	nlookup_done(&nd);
2430 	return (error);
2431 }
2432 
2433 
2434 /*
2435  * unlinkat_args(int fd, char *path, int flags)
2436  *
2437  * Delete the file or directory entry pointed to by fd/path.
2438  */
2439 int
2440 sys_unlinkat(struct unlinkat_args *uap)
2441 {
2442 	struct nlookupdata nd;
2443 	struct file *fp;
2444 	int error;
2445 
2446 	if (uap->flags & ~AT_REMOVEDIR)
2447 		return (EINVAL);
2448 
2449 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2450 	if (error == 0) {
2451 		if (uap->flags & AT_REMOVEDIR)
2452 			error = kern_rmdir(&nd);
2453 		else
2454 			error = kern_unlink(&nd);
2455 	}
2456 	nlookup_done_at(&nd, fp);
2457 	return (error);
2458 }
2459 
2460 int
2461 kern_lseek(int fd, off_t offset, int whence, off_t *res)
2462 {
2463 	struct thread *td = curthread;
2464 	struct proc *p = td->td_proc;
2465 	struct file *fp;
2466 	struct vnode *vp;
2467 	struct vattr vattr;
2468 	off_t new_offset;
2469 	int error;
2470 
2471 	fp = holdfp(p->p_fd, fd, -1);
2472 	if (fp == NULL)
2473 		return (EBADF);
2474 	if (fp->f_type != DTYPE_VNODE) {
2475 		error = ESPIPE;
2476 		goto done;
2477 	}
2478 	vp = (struct vnode *)fp->f_data;
2479 
2480 	switch (whence) {
2481 	case L_INCR:
2482 		spin_lock(&fp->f_spin);
2483 		new_offset = fp->f_offset + offset;
2484 		error = 0;
2485 		break;
2486 	case L_XTND:
2487 		error = VOP_GETATTR(vp, &vattr);
2488 		spin_lock(&fp->f_spin);
2489 		new_offset = offset + vattr.va_size;
2490 		break;
2491 	case L_SET:
2492 		new_offset = offset;
2493 		error = 0;
2494 		spin_lock(&fp->f_spin);
2495 		break;
2496 	default:
2497 		new_offset = 0;
2498 		error = EINVAL;
2499 		spin_lock(&fp->f_spin);
2500 		break;
2501 	}
2502 
2503 	/*
2504 	 * Validate the seek position.  Negative offsets are not allowed
2505 	 * for regular files or directories.
2506 	 *
2507 	 * Normally we would also not want to allow negative offsets for
2508 	 * character and block-special devices.  However kvm addresses
2509 	 * on 64 bit architectures might appear to be negative and must
2510 	 * be allowed.
2511 	 */
2512 	if (error == 0) {
2513 		if (new_offset < 0 &&
2514 		    (vp->v_type == VREG || vp->v_type == VDIR)) {
2515 			error = EINVAL;
2516 		} else {
2517 			fp->f_offset = new_offset;
2518 		}
2519 	}
2520 	*res = fp->f_offset;
2521 	spin_unlock(&fp->f_spin);
2522 done:
2523 	fdrop(fp);
2524 	return (error);
2525 }
2526 
2527 /*
2528  * lseek_args(int fd, int pad, off_t offset, int whence)
2529  *
2530  * Reposition read/write file offset.
2531  */
2532 int
2533 sys_lseek(struct lseek_args *uap)
2534 {
2535 	int error;
2536 
2537 	error = kern_lseek(uap->fd, uap->offset, uap->whence,
2538 			   &uap->sysmsg_offset);
2539 
2540 	return (error);
2541 }
2542 
2543 /*
2544  * Check if current process can access given file.  amode is a bitmask of *_OK
2545  * access bits.  flags is a bitmask of AT_* flags.
2546  */
2547 int
2548 kern_access(struct nlookupdata *nd, int amode, int flags)
2549 {
2550 	struct vnode *vp;
2551 	int error, mode;
2552 
2553 	if (flags & ~AT_EACCESS)
2554 		return (EINVAL);
2555 	if ((error = nlookup(nd)) != 0)
2556 		return (error);
2557 retry:
2558 	error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_EXCLUSIVE, &vp);
2559 	if (error)
2560 		return (error);
2561 
2562 	/* Flags == 0 means only check for existence. */
2563 	if (amode) {
2564 		mode = 0;
2565 		if (amode & R_OK)
2566 			mode |= VREAD;
2567 		if (amode & W_OK)
2568 			mode |= VWRITE;
2569 		if (amode & X_OK)
2570 			mode |= VEXEC;
2571 		if ((mode & VWRITE) == 0 ||
2572 		    (error = vn_writechk(vp, &nd->nl_nch)) == 0)
2573 			error = VOP_ACCESS_FLAGS(vp, mode, flags, nd->nl_cred);
2574 
2575 		/*
2576 		 * If the file handle is stale we have to re-resolve the
2577 		 * entry.  This is a hack at the moment.
2578 		 */
2579 		if (error == ESTALE) {
2580 			vput(vp);
2581 			cache_setunresolved(&nd->nl_nch);
2582 			error = cache_resolve(&nd->nl_nch, nd->nl_cred);
2583 			if (error == 0) {
2584 				vp = NULL;
2585 				goto retry;
2586 			}
2587 			return(error);
2588 		}
2589 	}
2590 	vput(vp);
2591 	return (error);
2592 }
2593 
2594 /*
2595  * access_args(char *path, int flags)
2596  *
2597  * Check access permissions.
2598  */
2599 int
2600 sys_access(struct access_args *uap)
2601 {
2602 	struct nlookupdata nd;
2603 	int error;
2604 
2605 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2606 	if (error == 0)
2607 		error = kern_access(&nd, uap->flags, 0);
2608 	nlookup_done(&nd);
2609 	return (error);
2610 }
2611 
2612 
2613 /*
2614  * faccessat_args(int fd, char *path, int amode, int flags)
2615  *
2616  * Check access permissions.
2617  */
2618 int
2619 sys_faccessat(struct faccessat_args *uap)
2620 {
2621 	struct nlookupdata nd;
2622 	struct file *fp;
2623 	int error;
2624 
2625 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE,
2626 				NLC_FOLLOW);
2627 	if (error == 0)
2628 		error = kern_access(&nd, uap->amode, uap->flags);
2629 	nlookup_done_at(&nd, fp);
2630 	return (error);
2631 }
2632 
2633 
2634 int
2635 kern_stat(struct nlookupdata *nd, struct stat *st)
2636 {
2637 	int error;
2638 	struct vnode *vp;
2639 
2640 	if ((error = nlookup(nd)) != 0)
2641 		return (error);
2642 again:
2643 	if ((vp = nd->nl_nch.ncp->nc_vp) == NULL)
2644 		return (ENOENT);
2645 
2646 	if ((error = vget(vp, LK_SHARED)) != 0)
2647 		return (error);
2648 	error = vn_stat(vp, st, nd->nl_cred);
2649 
2650 	/*
2651 	 * If the file handle is stale we have to re-resolve the entry.  This
2652 	 * is a hack at the moment.
2653 	 */
2654 	if (error == ESTALE) {
2655 		vput(vp);
2656 		cache_setunresolved(&nd->nl_nch);
2657 		error = cache_resolve(&nd->nl_nch, nd->nl_cred);
2658 		if (error == 0)
2659 			goto again;
2660 	} else {
2661 		vput(vp);
2662 	}
2663 	return (error);
2664 }
2665 
2666 /*
2667  * stat_args(char *path, struct stat *ub)
2668  *
2669  * Get file status; this version follows links.
2670  */
2671 int
2672 sys_stat(struct stat_args *uap)
2673 {
2674 	struct nlookupdata nd;
2675 	struct stat st;
2676 	int error;
2677 
2678 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2679 	if (error == 0) {
2680 		error = kern_stat(&nd, &st);
2681 		if (error == 0)
2682 			error = copyout(&st, uap->ub, sizeof(*uap->ub));
2683 	}
2684 	nlookup_done(&nd);
2685 	return (error);
2686 }
2687 
2688 /*
2689  * lstat_args(char *path, struct stat *ub)
2690  *
2691  * Get file status; this version does not follow links.
2692  */
2693 int
2694 sys_lstat(struct lstat_args *uap)
2695 {
2696 	struct nlookupdata nd;
2697 	struct stat st;
2698 	int error;
2699 
2700 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2701 	if (error == 0) {
2702 		error = kern_stat(&nd, &st);
2703 		if (error == 0)
2704 			error = copyout(&st, uap->ub, sizeof(*uap->ub));
2705 	}
2706 	nlookup_done(&nd);
2707 	return (error);
2708 }
2709 
2710 /*
2711  * fstatat_args(int fd, char *path, struct stat *sb, int flags)
2712  *
2713  * Get status of file pointed to by fd/path.
2714  */
2715 int
2716 sys_fstatat(struct fstatat_args *uap)
2717 {
2718 	struct nlookupdata nd;
2719 	struct stat st;
2720 	int error;
2721 	int flags;
2722 	struct file *fp;
2723 
2724 	if (uap->flags & ~AT_SYMLINK_NOFOLLOW)
2725 		return (EINVAL);
2726 
2727 	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
2728 
2729 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path,
2730 				UIO_USERSPACE, flags);
2731 	if (error == 0) {
2732 		error = kern_stat(&nd, &st);
2733 		if (error == 0)
2734 			error = copyout(&st, uap->sb, sizeof(*uap->sb));
2735 	}
2736 	nlookup_done_at(&nd, fp);
2737 	return (error);
2738 }
2739 
2740 /*
2741  * pathconf_Args(char *path, int name)
2742  *
2743  * Get configurable pathname variables.
2744  */
2745 int
2746 sys_pathconf(struct pathconf_args *uap)
2747 {
2748 	struct nlookupdata nd;
2749 	struct vnode *vp;
2750 	int error;
2751 
2752 	vp = NULL;
2753 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2754 	if (error == 0)
2755 		error = nlookup(&nd);
2756 	if (error == 0)
2757 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
2758 	nlookup_done(&nd);
2759 	if (error == 0) {
2760 		error = VOP_PATHCONF(vp, uap->name, &uap->sysmsg_reg);
2761 		vput(vp);
2762 	}
2763 	return (error);
2764 }
2765 
2766 /*
2767  * XXX: daver
2768  * kern_readlink isn't properly split yet.  There is a copyin burried
2769  * in VOP_READLINK().
2770  */
2771 int
2772 kern_readlink(struct nlookupdata *nd, char *buf, int count, int *res)
2773 {
2774 	struct thread *td = curthread;
2775 	struct vnode *vp;
2776 	struct iovec aiov;
2777 	struct uio auio;
2778 	int error;
2779 
2780 	if ((error = nlookup(nd)) != 0)
2781 		return (error);
2782 	error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_EXCLUSIVE, &vp);
2783 	if (error)
2784 		return (error);
2785 	if (vp->v_type != VLNK) {
2786 		error = EINVAL;
2787 	} else {
2788 		aiov.iov_base = buf;
2789 		aiov.iov_len = count;
2790 		auio.uio_iov = &aiov;
2791 		auio.uio_iovcnt = 1;
2792 		auio.uio_offset = 0;
2793 		auio.uio_rw = UIO_READ;
2794 		auio.uio_segflg = UIO_USERSPACE;
2795 		auio.uio_td = td;
2796 		auio.uio_resid = count;
2797 		error = VOP_READLINK(vp, &auio, td->td_ucred);
2798 	}
2799 	vput(vp);
2800 	*res = count - auio.uio_resid;
2801 	return (error);
2802 }
2803 
2804 /*
2805  * readlink_args(char *path, char *buf, int count)
2806  *
2807  * Return target name of a symbolic link.
2808  */
2809 int
2810 sys_readlink(struct readlink_args *uap)
2811 {
2812 	struct nlookupdata nd;
2813 	int error;
2814 
2815 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2816 	if (error == 0) {
2817 		error = kern_readlink(&nd, uap->buf, uap->count,
2818 					&uap->sysmsg_result);
2819 	}
2820 	nlookup_done(&nd);
2821 	return (error);
2822 }
2823 
2824 /*
2825  * readlinkat_args(int fd, char *path, char *buf, size_t bufsize)
2826  *
2827  * Return target name of a symbolic link.  The path is relative to the
2828  * directory associated with fd.
2829  */
2830 int
2831 sys_readlinkat(struct readlinkat_args *uap)
2832 {
2833 	struct nlookupdata nd;
2834 	struct file *fp;
2835 	int error;
2836 
2837 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
2838 	if (error == 0) {
2839 		error = kern_readlink(&nd, uap->buf, uap->bufsize,
2840 					&uap->sysmsg_result);
2841 	}
2842 	nlookup_done_at(&nd, fp);
2843 	return (error);
2844 }
2845 
2846 static int
2847 setfflags(struct vnode *vp, int flags)
2848 {
2849 	struct thread *td = curthread;
2850 	int error;
2851 	struct vattr vattr;
2852 
2853 	/*
2854 	 * Prevent non-root users from setting flags on devices.  When
2855 	 * a device is reused, users can retain ownership of the device
2856 	 * if they are allowed to set flags and programs assume that
2857 	 * chown can't fail when done as root.
2858 	 */
2859 	if ((vp->v_type == VCHR || vp->v_type == VBLK) &&
2860 	    ((error = priv_check_cred(td->td_ucred, PRIV_VFS_CHFLAGS_DEV, 0)) != 0))
2861 		return (error);
2862 
2863 	/*
2864 	 * note: vget is required for any operation that might mod the vnode
2865 	 * so VINACTIVE is properly cleared.
2866 	 */
2867 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
2868 		VATTR_NULL(&vattr);
2869 		vattr.va_flags = flags;
2870 		error = VOP_SETATTR(vp, &vattr, td->td_ucred);
2871 		vput(vp);
2872 	}
2873 	return (error);
2874 }
2875 
2876 /*
2877  * chflags(char *path, int flags)
2878  *
2879  * Change flags of a file given a path name.
2880  */
2881 int
2882 sys_chflags(struct chflags_args *uap)
2883 {
2884 	struct nlookupdata nd;
2885 	struct vnode *vp;
2886 	int error;
2887 
2888 	vp = NULL;
2889 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2890 	if (error == 0)
2891 		error = nlookup(&nd);
2892 	if (error == 0)
2893 		error = ncp_writechk(&nd.nl_nch);
2894 	if (error == 0)
2895 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
2896 	nlookup_done(&nd);
2897 	if (error == 0) {
2898 		error = setfflags(vp, uap->flags);
2899 		vrele(vp);
2900 	}
2901 	return (error);
2902 }
2903 
2904 /*
2905  * lchflags(char *path, int flags)
2906  *
2907  * Change flags of a file given a path name, but don't follow symlinks.
2908  */
2909 int
2910 sys_lchflags(struct lchflags_args *uap)
2911 {
2912 	struct nlookupdata nd;
2913 	struct vnode *vp;
2914 	int error;
2915 
2916 	vp = NULL;
2917 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2918 	if (error == 0)
2919 		error = nlookup(&nd);
2920 	if (error == 0)
2921 		error = ncp_writechk(&nd.nl_nch);
2922 	if (error == 0)
2923 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
2924 	nlookup_done(&nd);
2925 	if (error == 0) {
2926 		error = setfflags(vp, uap->flags);
2927 		vrele(vp);
2928 	}
2929 	return (error);
2930 }
2931 
2932 /*
2933  * fchflags_args(int fd, int flags)
2934  *
2935  * Change flags of a file given a file descriptor.
2936  */
2937 int
2938 sys_fchflags(struct fchflags_args *uap)
2939 {
2940 	struct thread *td = curthread;
2941 	struct proc *p = td->td_proc;
2942 	struct file *fp;
2943 	int error;
2944 
2945 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
2946 		return (error);
2947 	if (fp->f_nchandle.ncp)
2948 		error = ncp_writechk(&fp->f_nchandle);
2949 	if (error == 0)
2950 		error = setfflags((struct vnode *) fp->f_data, uap->flags);
2951 	fdrop(fp);
2952 	return (error);
2953 }
2954 
2955 static int
2956 setfmode(struct vnode *vp, int mode)
2957 {
2958 	struct thread *td = curthread;
2959 	int error;
2960 	struct vattr vattr;
2961 
2962 	/*
2963 	 * note: vget is required for any operation that might mod the vnode
2964 	 * so VINACTIVE is properly cleared.
2965 	 */
2966 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
2967 		VATTR_NULL(&vattr);
2968 		vattr.va_mode = mode & ALLPERMS;
2969 		error = VOP_SETATTR(vp, &vattr, td->td_ucred);
2970 		vput(vp);
2971 	}
2972 	return error;
2973 }
2974 
2975 int
2976 kern_chmod(struct nlookupdata *nd, int mode)
2977 {
2978 	struct vnode *vp;
2979 	int error;
2980 
2981 	if ((error = nlookup(nd)) != 0)
2982 		return (error);
2983 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
2984 		return (error);
2985 	if ((error = ncp_writechk(&nd->nl_nch)) == 0)
2986 		error = setfmode(vp, mode);
2987 	vrele(vp);
2988 	return (error);
2989 }
2990 
2991 /*
2992  * chmod_args(char *path, int mode)
2993  *
2994  * Change mode of a file given path name.
2995  */
2996 int
2997 sys_chmod(struct chmod_args *uap)
2998 {
2999 	struct nlookupdata nd;
3000 	int error;
3001 
3002 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3003 	if (error == 0)
3004 		error = kern_chmod(&nd, uap->mode);
3005 	nlookup_done(&nd);
3006 	return (error);
3007 }
3008 
3009 /*
3010  * lchmod_args(char *path, int mode)
3011  *
3012  * Change mode of a file given path name (don't follow links.)
3013  */
3014 int
3015 sys_lchmod(struct lchmod_args *uap)
3016 {
3017 	struct nlookupdata nd;
3018 	int error;
3019 
3020 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3021 	if (error == 0)
3022 		error = kern_chmod(&nd, uap->mode);
3023 	nlookup_done(&nd);
3024 	return (error);
3025 }
3026 
3027 /*
3028  * fchmod_args(int fd, int mode)
3029  *
3030  * Change mode of a file given a file descriptor.
3031  */
3032 int
3033 sys_fchmod(struct fchmod_args *uap)
3034 {
3035 	struct thread *td = curthread;
3036 	struct proc *p = td->td_proc;
3037 	struct file *fp;
3038 	int error;
3039 
3040 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
3041 		return (error);
3042 	if (fp->f_nchandle.ncp)
3043 		error = ncp_writechk(&fp->f_nchandle);
3044 	if (error == 0)
3045 		error = setfmode((struct vnode *)fp->f_data, uap->mode);
3046 	fdrop(fp);
3047 	return (error);
3048 }
3049 
3050 /*
3051  * fchmodat_args(char *path, int mode)
3052  *
3053  * Change mode of a file pointed to by fd/path.
3054  */
3055 int
3056 sys_fchmodat(struct fchmodat_args *uap)
3057 {
3058 	struct nlookupdata nd;
3059 	struct file *fp;
3060 	int error;
3061 	int flags;
3062 
3063 	if (uap->flags & ~AT_SYMLINK_NOFOLLOW)
3064 		return (EINVAL);
3065 	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
3066 
3067 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path,
3068 				UIO_USERSPACE, flags);
3069 	if (error == 0)
3070 		error = kern_chmod(&nd, uap->mode);
3071 	nlookup_done_at(&nd, fp);
3072 	return (error);
3073 }
3074 
3075 static int
3076 setfown(struct mount *mp, struct vnode *vp, uid_t uid, gid_t gid)
3077 {
3078 	struct thread *td = curthread;
3079 	int error;
3080 	struct vattr vattr;
3081 	uid_t o_uid;
3082 	gid_t o_gid;
3083 	uint64_t size;
3084 
3085 	/*
3086 	 * note: vget is required for any operation that might mod the vnode
3087 	 * so VINACTIVE is properly cleared.
3088 	 */
3089 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
3090 		if ((error = VOP_GETATTR(vp, &vattr)) != 0)
3091 			return error;
3092 		o_uid = vattr.va_uid;
3093 		o_gid = vattr.va_gid;
3094 		size = vattr.va_size;
3095 
3096 		VATTR_NULL(&vattr);
3097 		vattr.va_uid = uid;
3098 		vattr.va_gid = gid;
3099 		error = VOP_SETATTR(vp, &vattr, td->td_ucred);
3100 		vput(vp);
3101 	}
3102 
3103 	if (error == 0) {
3104 		if (uid == -1)
3105 			uid = o_uid;
3106 		if (gid == -1)
3107 			gid = o_gid;
3108 		VFS_ACCOUNT(mp, o_uid, o_gid, -size);
3109 		VFS_ACCOUNT(mp,   uid,   gid,  size);
3110 	}
3111 
3112 	return error;
3113 }
3114 
3115 int
3116 kern_chown(struct nlookupdata *nd, int uid, int gid)
3117 {
3118 	struct vnode *vp;
3119 	int error;
3120 
3121 	if ((error = nlookup(nd)) != 0)
3122 		return (error);
3123 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
3124 		return (error);
3125 	if ((error = ncp_writechk(&nd->nl_nch)) == 0)
3126 		error = setfown(nd->nl_nch.mount, vp, uid, gid);
3127 	vrele(vp);
3128 	return (error);
3129 }
3130 
3131 /*
3132  * chown(char *path, int uid, int gid)
3133  *
3134  * Set ownership given a path name.
3135  */
3136 int
3137 sys_chown(struct chown_args *uap)
3138 {
3139 	struct nlookupdata nd;
3140 	int error;
3141 
3142 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3143 	if (error == 0)
3144 		error = kern_chown(&nd, uap->uid, uap->gid);
3145 	nlookup_done(&nd);
3146 	return (error);
3147 }
3148 
3149 /*
3150  * lchown_args(char *path, int uid, int gid)
3151  *
3152  * Set ownership given a path name, do not cross symlinks.
3153  */
3154 int
3155 sys_lchown(struct lchown_args *uap)
3156 {
3157 	struct nlookupdata nd;
3158 	int error;
3159 
3160 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3161 	if (error == 0)
3162 		error = kern_chown(&nd, uap->uid, uap->gid);
3163 	nlookup_done(&nd);
3164 	return (error);
3165 }
3166 
3167 /*
3168  * fchown_args(int fd, int uid, int gid)
3169  *
3170  * Set ownership given a file descriptor.
3171  */
3172 int
3173 sys_fchown(struct fchown_args *uap)
3174 {
3175 	struct thread *td = curthread;
3176 	struct proc *p = td->td_proc;
3177 	struct file *fp;
3178 	int error;
3179 
3180 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
3181 		return (error);
3182 	if (fp->f_nchandle.ncp)
3183 		error = ncp_writechk(&fp->f_nchandle);
3184 	if (error == 0)
3185 		error = setfown(p->p_fd->fd_ncdir.mount,
3186 			(struct vnode *)fp->f_data, uap->uid, uap->gid);
3187 	fdrop(fp);
3188 	return (error);
3189 }
3190 
3191 /*
3192  * fchownat(int fd, char *path, int uid, int gid, int flags)
3193  *
3194  * Set ownership of file pointed to by fd/path.
3195  */
3196 int
3197 sys_fchownat(struct fchownat_args *uap)
3198 {
3199 	struct nlookupdata nd;
3200 	struct file *fp;
3201 	int error;
3202 	int flags;
3203 
3204 	if (uap->flags & ~AT_SYMLINK_NOFOLLOW)
3205 		return (EINVAL);
3206 	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
3207 
3208 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path,
3209 				UIO_USERSPACE, flags);
3210 	if (error == 0)
3211 		error = kern_chown(&nd, uap->uid, uap->gid);
3212 	nlookup_done_at(&nd, fp);
3213 	return (error);
3214 }
3215 
3216 
3217 static int
3218 getutimes(const struct timeval *tvp, struct timespec *tsp)
3219 {
3220 	struct timeval tv[2];
3221 
3222 	if (tvp == NULL) {
3223 		microtime(&tv[0]);
3224 		TIMEVAL_TO_TIMESPEC(&tv[0], &tsp[0]);
3225 		tsp[1] = tsp[0];
3226 	} else {
3227 		TIMEVAL_TO_TIMESPEC(&tvp[0], &tsp[0]);
3228 		TIMEVAL_TO_TIMESPEC(&tvp[1], &tsp[1]);
3229 	}
3230 	return 0;
3231 }
3232 
3233 static int
3234 setutimes(struct vnode *vp, struct vattr *vattr,
3235 	  const struct timespec *ts, int nullflag)
3236 {
3237 	struct thread *td = curthread;
3238 	int error;
3239 
3240 	VATTR_NULL(vattr);
3241 	vattr->va_atime = ts[0];
3242 	vattr->va_mtime = ts[1];
3243 	if (nullflag)
3244 		vattr->va_vaflags |= VA_UTIMES_NULL;
3245 	error = VOP_SETATTR(vp, vattr, td->td_ucred);
3246 
3247 	return error;
3248 }
3249 
3250 int
3251 kern_utimes(struct nlookupdata *nd, struct timeval *tptr)
3252 {
3253 	struct timespec ts[2];
3254 	struct vnode *vp;
3255 	struct vattr vattr;
3256 	int error;
3257 
3258 	if ((error = getutimes(tptr, ts)) != 0)
3259 		return (error);
3260 
3261 	/*
3262 	 * NOTE: utimes() succeeds for the owner even if the file
3263 	 * is not user-writable.
3264 	 */
3265 	nd->nl_flags |= NLC_OWN | NLC_WRITE;
3266 
3267 	if ((error = nlookup(nd)) != 0)
3268 		return (error);
3269 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3270 		return (error);
3271 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
3272 		return (error);
3273 
3274 	/*
3275 	 * note: vget is required for any operation that might mod the vnode
3276 	 * so VINACTIVE is properly cleared.
3277 	 */
3278 	if ((error = vn_writechk(vp, &nd->nl_nch)) == 0) {
3279 		error = vget(vp, LK_EXCLUSIVE);
3280 		if (error == 0) {
3281 			error = setutimes(vp, &vattr, ts, (tptr == NULL));
3282 			vput(vp);
3283 		}
3284 	}
3285 	vrele(vp);
3286 	return (error);
3287 }
3288 
3289 /*
3290  * utimes_args(char *path, struct timeval *tptr)
3291  *
3292  * Set the access and modification times of a file.
3293  */
3294 int
3295 sys_utimes(struct utimes_args *uap)
3296 {
3297 	struct timeval tv[2];
3298 	struct nlookupdata nd;
3299 	int error;
3300 
3301 	if (uap->tptr) {
3302  		error = copyin(uap->tptr, tv, sizeof(tv));
3303 		if (error)
3304 			return (error);
3305 	}
3306 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3307 	if (error == 0)
3308 		error = kern_utimes(&nd, uap->tptr ? tv : NULL);
3309 	nlookup_done(&nd);
3310 	return (error);
3311 }
3312 
3313 /*
3314  * lutimes_args(char *path, struct timeval *tptr)
3315  *
3316  * Set the access and modification times of a file.
3317  */
3318 int
3319 sys_lutimes(struct lutimes_args *uap)
3320 {
3321 	struct timeval tv[2];
3322 	struct nlookupdata nd;
3323 	int error;
3324 
3325 	if (uap->tptr) {
3326 		error = copyin(uap->tptr, tv, sizeof(tv));
3327 		if (error)
3328 			return (error);
3329 	}
3330 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3331 	if (error == 0)
3332 		error = kern_utimes(&nd, uap->tptr ? tv : NULL);
3333 	nlookup_done(&nd);
3334 	return (error);
3335 }
3336 
3337 /*
3338  * Set utimes on a file descriptor.  The creds used to open the
3339  * file are used to determine whether the operation is allowed
3340  * or not.
3341  */
3342 int
3343 kern_futimes(int fd, struct timeval *tptr)
3344 {
3345 	struct thread *td = curthread;
3346 	struct proc *p = td->td_proc;
3347 	struct timespec ts[2];
3348 	struct file *fp;
3349 	struct vnode *vp;
3350 	struct vattr vattr;
3351 	int error;
3352 
3353 	error = getutimes(tptr, ts);
3354 	if (error)
3355 		return (error);
3356 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
3357 		return (error);
3358 	if (fp->f_nchandle.ncp)
3359 		error = ncp_writechk(&fp->f_nchandle);
3360 	if (error == 0) {
3361 		vp = fp->f_data;
3362 		error = vget(vp, LK_EXCLUSIVE);
3363 		if (error == 0) {
3364 			error = VOP_GETATTR(vp, &vattr);
3365 			if (error == 0) {
3366 				error = naccess_va(&vattr, NLC_OWN | NLC_WRITE,
3367 						   fp->f_cred);
3368 			}
3369 			if (error == 0) {
3370 				error = setutimes(vp, &vattr, ts,
3371 						  (tptr == NULL));
3372 			}
3373 			vput(vp);
3374 		}
3375 	}
3376 	fdrop(fp);
3377 	return (error);
3378 }
3379 
3380 /*
3381  * futimes_args(int fd, struct timeval *tptr)
3382  *
3383  * Set the access and modification times of a file.
3384  */
3385 int
3386 sys_futimes(struct futimes_args *uap)
3387 {
3388 	struct timeval tv[2];
3389 	int error;
3390 
3391 	if (uap->tptr) {
3392 		error = copyin(uap->tptr, tv, sizeof(tv));
3393 		if (error)
3394 			return (error);
3395 	}
3396 	error = kern_futimes(uap->fd, uap->tptr ? tv : NULL);
3397 
3398 	return (error);
3399 }
3400 
3401 int
3402 kern_truncate(struct nlookupdata *nd, off_t length)
3403 {
3404 	struct vnode *vp;
3405 	struct vattr vattr;
3406 	int error;
3407 	uid_t uid = 0;
3408 	gid_t gid = 0;
3409 	uint64_t old_size = 0;
3410 
3411 	if (length < 0)
3412 		return(EINVAL);
3413 	nd->nl_flags |= NLC_WRITE | NLC_TRUNCATE;
3414 	if ((error = nlookup(nd)) != 0)
3415 		return (error);
3416 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3417 		return (error);
3418 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
3419 		return (error);
3420 	if ((error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY)) != 0) {
3421 		vrele(vp);
3422 		return (error);
3423 	}
3424 	if (vp->v_type == VDIR) {
3425 		error = EISDIR;
3426 		goto done;
3427 	}
3428 	if (vfs_quota_enabled) {
3429 		error = VOP_GETATTR(vp, &vattr);
3430 		KASSERT(error == 0, ("kern_truncate(): VOP_GETATTR didn't return 0"));
3431 		uid = vattr.va_uid;
3432 		gid = vattr.va_gid;
3433 		old_size = vattr.va_size;
3434 	}
3435 
3436 	if ((error = vn_writechk(vp, &nd->nl_nch)) == 0) {
3437 		VATTR_NULL(&vattr);
3438 		vattr.va_size = length;
3439 		error = VOP_SETATTR(vp, &vattr, nd->nl_cred);
3440 		VFS_ACCOUNT(nd->nl_nch.mount, uid, gid, length - old_size);
3441 	}
3442 done:
3443 	vput(vp);
3444 	return (error);
3445 }
3446 
3447 /*
3448  * truncate(char *path, int pad, off_t length)
3449  *
3450  * Truncate a file given its path name.
3451  */
3452 int
3453 sys_truncate(struct truncate_args *uap)
3454 {
3455 	struct nlookupdata nd;
3456 	int error;
3457 
3458 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3459 	if (error == 0)
3460 		error = kern_truncate(&nd, uap->length);
3461 	nlookup_done(&nd);
3462 	return error;
3463 }
3464 
3465 int
3466 kern_ftruncate(int fd, off_t length)
3467 {
3468 	struct thread *td = curthread;
3469 	struct proc *p = td->td_proc;
3470 	struct vattr vattr;
3471 	struct vnode *vp;
3472 	struct file *fp;
3473 	int error;
3474 	uid_t uid = 0;
3475 	gid_t gid = 0;
3476 	uint64_t old_size = 0;
3477 	struct mount *mp;
3478 
3479 	if (length < 0)
3480 		return(EINVAL);
3481 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
3482 		return (error);
3483 	if (fp->f_nchandle.ncp) {
3484 		error = ncp_writechk(&fp->f_nchandle);
3485 		if (error)
3486 			goto done;
3487 	}
3488 	if ((fp->f_flag & FWRITE) == 0) {
3489 		error = EINVAL;
3490 		goto done;
3491 	}
3492 	if (fp->f_flag & FAPPENDONLY) {	/* inode was set s/uapnd */
3493 		error = EINVAL;
3494 		goto done;
3495 	}
3496 	vp = (struct vnode *)fp->f_data;
3497 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3498 	if (vp->v_type == VDIR) {
3499 		error = EISDIR;
3500 		goto done;
3501 	}
3502 
3503 	if (vfs_quota_enabled) {
3504 		error = VOP_GETATTR(vp, &vattr);
3505 		KASSERT(error == 0, ("kern_ftruncate(): VOP_GETATTR didn't return 0"));
3506 		uid = vattr.va_uid;
3507 		gid = vattr.va_gid;
3508 		old_size = vattr.va_size;
3509 	}
3510 
3511 	if ((error = vn_writechk(vp, NULL)) == 0) {
3512 		VATTR_NULL(&vattr);
3513 		vattr.va_size = length;
3514 		error = VOP_SETATTR(vp, &vattr, fp->f_cred);
3515 		mp = vq_vptomp(vp);
3516 		VFS_ACCOUNT(mp, uid, gid, length - old_size);
3517 	}
3518 	vn_unlock(vp);
3519 done:
3520 	fdrop(fp);
3521 	return (error);
3522 }
3523 
3524 /*
3525  * ftruncate_args(int fd, int pad, off_t length)
3526  *
3527  * Truncate a file given a file descriptor.
3528  */
3529 int
3530 sys_ftruncate(struct ftruncate_args *uap)
3531 {
3532 	int error;
3533 
3534 	error = kern_ftruncate(uap->fd, uap->length);
3535 
3536 	return (error);
3537 }
3538 
3539 /*
3540  * fsync(int fd)
3541  *
3542  * Sync an open file.
3543  */
3544 int
3545 sys_fsync(struct fsync_args *uap)
3546 {
3547 	struct thread *td = curthread;
3548 	struct proc *p = td->td_proc;
3549 	struct vnode *vp;
3550 	struct file *fp;
3551 	vm_object_t obj;
3552 	int error;
3553 
3554 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
3555 		return (error);
3556 	vp = (struct vnode *)fp->f_data;
3557 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3558 	if ((obj = vp->v_object) != NULL)
3559 		vm_object_page_clean(obj, 0, 0, 0);
3560 	error = VOP_FSYNC(vp, MNT_WAIT, VOP_FSYNC_SYSCALL);
3561 	if (error == 0 && vp->v_mount)
3562 		error = buf_fsync(vp);
3563 	vn_unlock(vp);
3564 	fdrop(fp);
3565 
3566 	return (error);
3567 }
3568 
3569 int
3570 kern_rename(struct nlookupdata *fromnd, struct nlookupdata *tond)
3571 {
3572 	struct nchandle fnchd;
3573 	struct nchandle tnchd;
3574 	struct namecache *ncp;
3575 	struct vnode *fdvp;
3576 	struct vnode *tdvp;
3577 	struct mount *mp;
3578 	int error;
3579 
3580 	bwillinode(1);
3581 	fromnd->nl_flags |= NLC_REFDVP | NLC_RENAME_SRC;
3582 	if ((error = nlookup(fromnd)) != 0)
3583 		return (error);
3584 	if ((fnchd.ncp = fromnd->nl_nch.ncp->nc_parent) == NULL)
3585 		return (ENOENT);
3586 	fnchd.mount = fromnd->nl_nch.mount;
3587 	cache_hold(&fnchd);
3588 
3589 	/*
3590 	 * unlock the source nch so we can lookup the target nch without
3591 	 * deadlocking.  The target may or may not exist so we do not check
3592 	 * for a target vp like kern_mkdir() and other creation functions do.
3593 	 *
3594 	 * The source and target directories are ref'd and rechecked after
3595 	 * everything is relocked to determine if the source or target file
3596 	 * has been renamed.
3597 	 */
3598 	KKASSERT(fromnd->nl_flags & NLC_NCPISLOCKED);
3599 	fromnd->nl_flags &= ~NLC_NCPISLOCKED;
3600 	cache_unlock(&fromnd->nl_nch);
3601 
3602 	tond->nl_flags |= NLC_RENAME_DST | NLC_REFDVP;
3603 	if ((error = nlookup(tond)) != 0) {
3604 		cache_drop(&fnchd);
3605 		return (error);
3606 	}
3607 	if ((tnchd.ncp = tond->nl_nch.ncp->nc_parent) == NULL) {
3608 		cache_drop(&fnchd);
3609 		return (ENOENT);
3610 	}
3611 	tnchd.mount = tond->nl_nch.mount;
3612 	cache_hold(&tnchd);
3613 
3614 	/*
3615 	 * If the source and target are the same there is nothing to do
3616 	 */
3617 	if (fromnd->nl_nch.ncp == tond->nl_nch.ncp) {
3618 		cache_drop(&fnchd);
3619 		cache_drop(&tnchd);
3620 		return (0);
3621 	}
3622 
3623 	/*
3624 	 * Mount points cannot be renamed or overwritten
3625 	 */
3626 	if ((fromnd->nl_nch.ncp->nc_flag | tond->nl_nch.ncp->nc_flag) &
3627 	    NCF_ISMOUNTPT
3628 	) {
3629 		cache_drop(&fnchd);
3630 		cache_drop(&tnchd);
3631 		return (EINVAL);
3632 	}
3633 
3634 	/*
3635 	 * Relock the source ncp.  cache_relock() will deal with any
3636 	 * deadlocks against the already-locked tond and will also
3637 	 * make sure both are resolved.
3638 	 *
3639 	 * NOTE AFTER RELOCKING: The source or target ncp may have become
3640 	 * invalid while they were unlocked, nc_vp and nc_mount could
3641 	 * be NULL.
3642 	 */
3643 	cache_relock(&fromnd->nl_nch, fromnd->nl_cred,
3644 		     &tond->nl_nch, tond->nl_cred);
3645 	fromnd->nl_flags |= NLC_NCPISLOCKED;
3646 
3647 	/*
3648 	 * make sure the parent directories linkages are the same
3649 	 */
3650 	if (fnchd.ncp != fromnd->nl_nch.ncp->nc_parent ||
3651 	    tnchd.ncp != tond->nl_nch.ncp->nc_parent) {
3652 		cache_drop(&fnchd);
3653 		cache_drop(&tnchd);
3654 		return (ENOENT);
3655 	}
3656 
3657 	/*
3658 	 * Both the source and target must be within the same filesystem and
3659 	 * in the same filesystem as their parent directories within the
3660 	 * namecache topology.
3661 	 *
3662 	 * NOTE: fromnd's nc_mount or nc_vp could be NULL.
3663 	 */
3664 	mp = fnchd.mount;
3665 	if (mp != tnchd.mount || mp != fromnd->nl_nch.mount ||
3666 	    mp != tond->nl_nch.mount) {
3667 		cache_drop(&fnchd);
3668 		cache_drop(&tnchd);
3669 		return (EXDEV);
3670 	}
3671 
3672 	/*
3673 	 * Make sure the mount point is writable
3674 	 */
3675 	if ((error = ncp_writechk(&tond->nl_nch)) != 0) {
3676 		cache_drop(&fnchd);
3677 		cache_drop(&tnchd);
3678 		return (error);
3679 	}
3680 
3681 	/*
3682 	 * If the target exists and either the source or target is a directory,
3683 	 * then both must be directories.
3684 	 *
3685 	 * Due to relocking of the source, fromnd->nl_nch.ncp->nc_vp might h
3686 	 * have become NULL.
3687 	 */
3688 	if (tond->nl_nch.ncp->nc_vp) {
3689 		if (fromnd->nl_nch.ncp->nc_vp == NULL) {
3690 			error = ENOENT;
3691 		} else if (fromnd->nl_nch.ncp->nc_vp->v_type == VDIR) {
3692 			if (tond->nl_nch.ncp->nc_vp->v_type != VDIR)
3693 				error = ENOTDIR;
3694 		} else if (tond->nl_nch.ncp->nc_vp->v_type == VDIR) {
3695 			error = EISDIR;
3696 		}
3697 	}
3698 
3699 	/*
3700 	 * You cannot rename a source into itself or a subdirectory of itself.
3701 	 * We check this by travsersing the target directory upwards looking
3702 	 * for a match against the source.
3703 	 *
3704 	 * XXX MPSAFE
3705 	 */
3706 	if (error == 0) {
3707 		for (ncp = tnchd.ncp; ncp; ncp = ncp->nc_parent) {
3708 			if (fromnd->nl_nch.ncp == ncp) {
3709 				error = EINVAL;
3710 				break;
3711 			}
3712 		}
3713 	}
3714 
3715 	cache_drop(&fnchd);
3716 	cache_drop(&tnchd);
3717 
3718 	/*
3719 	 * Even though the namespaces are different, they may still represent
3720 	 * hardlinks to the same file.  The filesystem might have a hard time
3721 	 * with this so we issue a NREMOVE of the source instead of a NRENAME
3722 	 * when we detect the situation.
3723 	 */
3724 	if (error == 0) {
3725 		fdvp = fromnd->nl_dvp;
3726 		tdvp = tond->nl_dvp;
3727 		if (fdvp == NULL || tdvp == NULL) {
3728 			error = EPERM;
3729 		} else if (fromnd->nl_nch.ncp->nc_vp == tond->nl_nch.ncp->nc_vp) {
3730 			error = VOP_NREMOVE(&fromnd->nl_nch, fdvp,
3731 					    fromnd->nl_cred);
3732 		} else {
3733 			error = VOP_NRENAME(&fromnd->nl_nch, &tond->nl_nch,
3734 					    fdvp, tdvp, tond->nl_cred);
3735 		}
3736 	}
3737 	return (error);
3738 }
3739 
3740 /*
3741  * rename_args(char *from, char *to)
3742  *
3743  * Rename files.  Source and destination must either both be directories,
3744  * or both not be directories.  If target is a directory, it must be empty.
3745  */
3746 int
3747 sys_rename(struct rename_args *uap)
3748 {
3749 	struct nlookupdata fromnd, tond;
3750 	int error;
3751 
3752 	error = nlookup_init(&fromnd, uap->from, UIO_USERSPACE, 0);
3753 	if (error == 0) {
3754 		error = nlookup_init(&tond, uap->to, UIO_USERSPACE, 0);
3755 		if (error == 0)
3756 			error = kern_rename(&fromnd, &tond);
3757 		nlookup_done(&tond);
3758 	}
3759 	nlookup_done(&fromnd);
3760 	return (error);
3761 }
3762 
3763 /*
3764  * renameat_args(int oldfd, char *old, int newfd, char *new)
3765  *
3766  * Rename files using paths relative to the directories associated with
3767  * oldfd and newfd.  Source and destination must either both be directories,
3768  * or both not be directories.  If target is a directory, it must be empty.
3769  */
3770 int
3771 sys_renameat(struct renameat_args *uap)
3772 {
3773 	struct nlookupdata oldnd, newnd;
3774 	struct file *oldfp, *newfp;
3775 	int error;
3776 
3777 	error = nlookup_init_at(&oldnd, &oldfp, uap->oldfd, uap->old,
3778 	    UIO_USERSPACE, 0);
3779 	if (error == 0) {
3780 		error = nlookup_init_at(&newnd, &newfp, uap->newfd, uap->new,
3781 		    UIO_USERSPACE, 0);
3782 		if (error == 0)
3783 			error = kern_rename(&oldnd, &newnd);
3784 		nlookup_done_at(&newnd, newfp);
3785 	}
3786 	nlookup_done_at(&oldnd, oldfp);
3787 	return (error);
3788 }
3789 
3790 int
3791 kern_mkdir(struct nlookupdata *nd, int mode)
3792 {
3793 	struct thread *td = curthread;
3794 	struct proc *p = td->td_proc;
3795 	struct vnode *vp;
3796 	struct vattr vattr;
3797 	int error;
3798 
3799 	bwillinode(1);
3800 	nd->nl_flags |= NLC_WILLBEDIR | NLC_CREATE | NLC_REFDVP;
3801 	if ((error = nlookup(nd)) != 0)
3802 		return (error);
3803 
3804 	if (nd->nl_nch.ncp->nc_vp)
3805 		return (EEXIST);
3806 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3807 		return (error);
3808 	VATTR_NULL(&vattr);
3809 	vattr.va_type = VDIR;
3810 	vattr.va_mode = (mode & ACCESSPERMS) &~ p->p_fd->fd_cmask;
3811 
3812 	vp = NULL;
3813 	error = VOP_NMKDIR(&nd->nl_nch, nd->nl_dvp, &vp, td->td_ucred, &vattr);
3814 	if (error == 0)
3815 		vput(vp);
3816 	return (error);
3817 }
3818 
3819 /*
3820  * mkdir_args(char *path, int mode)
3821  *
3822  * Make a directory file.
3823  */
3824 int
3825 sys_mkdir(struct mkdir_args *uap)
3826 {
3827 	struct nlookupdata nd;
3828 	int error;
3829 
3830 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3831 	if (error == 0)
3832 		error = kern_mkdir(&nd, uap->mode);
3833 	nlookup_done(&nd);
3834 	return (error);
3835 }
3836 
3837 /*
3838  * mkdirat_args(int fd, char *path, mode_t mode)
3839  *
3840  * Make a directory file.  The path is relative to the directory associated
3841  * with fd.
3842  */
3843 int
3844 sys_mkdirat(struct mkdirat_args *uap)
3845 {
3846 	struct nlookupdata nd;
3847 	struct file *fp;
3848 	int error;
3849 
3850 	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, UIO_USERSPACE, 0);
3851 	if (error == 0)
3852 		error = kern_mkdir(&nd, uap->mode);
3853 	nlookup_done_at(&nd, fp);
3854 	return (error);
3855 }
3856 
3857 int
3858 kern_rmdir(struct nlookupdata *nd)
3859 {
3860 	int error;
3861 
3862 	bwillinode(1);
3863 	nd->nl_flags |= NLC_DELETE | NLC_REFDVP;
3864 	if ((error = nlookup(nd)) != 0)
3865 		return (error);
3866 
3867 	/*
3868 	 * Do not allow directories representing mount points to be
3869 	 * deleted, even if empty.  Check write perms on mount point
3870 	 * in case the vnode is aliased (aka nullfs).
3871 	 */
3872 	if (nd->nl_nch.ncp->nc_flag & (NCF_ISMOUNTPT))
3873 		return (EINVAL);
3874 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3875 		return (error);
3876 	error = VOP_NRMDIR(&nd->nl_nch, nd->nl_dvp, nd->nl_cred);
3877 	return (error);
3878 }
3879 
3880 /*
3881  * rmdir_args(char *path)
3882  *
3883  * Remove a directory file.
3884  */
3885 int
3886 sys_rmdir(struct rmdir_args *uap)
3887 {
3888 	struct nlookupdata nd;
3889 	int error;
3890 
3891 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3892 	if (error == 0)
3893 		error = kern_rmdir(&nd);
3894 	nlookup_done(&nd);
3895 	return (error);
3896 }
3897 
3898 int
3899 kern_getdirentries(int fd, char *buf, u_int count, long *basep, int *res,
3900 		   enum uio_seg direction)
3901 {
3902 	struct thread *td = curthread;
3903 	struct proc *p = td->td_proc;
3904 	struct vnode *vp;
3905 	struct file *fp;
3906 	struct uio auio;
3907 	struct iovec aiov;
3908 	off_t loff;
3909 	int error, eofflag;
3910 
3911 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
3912 		return (error);
3913 	if ((fp->f_flag & FREAD) == 0) {
3914 		error = EBADF;
3915 		goto done;
3916 	}
3917 	vp = (struct vnode *)fp->f_data;
3918 unionread:
3919 	if (vp->v_type != VDIR) {
3920 		error = EINVAL;
3921 		goto done;
3922 	}
3923 	aiov.iov_base = buf;
3924 	aiov.iov_len = count;
3925 	auio.uio_iov = &aiov;
3926 	auio.uio_iovcnt = 1;
3927 	auio.uio_rw = UIO_READ;
3928 	auio.uio_segflg = direction;
3929 	auio.uio_td = td;
3930 	auio.uio_resid = count;
3931 	loff = auio.uio_offset = fp->f_offset;
3932 	error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, NULL, NULL);
3933 	fp->f_offset = auio.uio_offset;
3934 	if (error)
3935 		goto done;
3936 	if (count == auio.uio_resid) {
3937 		if (union_dircheckp) {
3938 			error = union_dircheckp(td, &vp, fp);
3939 			if (error == -1)
3940 				goto unionread;
3941 			if (error)
3942 				goto done;
3943 		}
3944 #if 0
3945 		if ((vp->v_flag & VROOT) &&
3946 		    (vp->v_mount->mnt_flag & MNT_UNION)) {
3947 			struct vnode *tvp = vp;
3948 			vp = vp->v_mount->mnt_vnodecovered;
3949 			vref(vp);
3950 			fp->f_data = vp;
3951 			fp->f_offset = 0;
3952 			vrele(tvp);
3953 			goto unionread;
3954 		}
3955 #endif
3956 	}
3957 
3958 	/*
3959 	 * WARNING!  *basep may not be wide enough to accomodate the
3960 	 * seek offset.   XXX should we hack this to return the upper 32 bits
3961 	 * for offsets greater then 4G?
3962 	 */
3963 	if (basep) {
3964 		*basep = (long)loff;
3965 	}
3966 	*res = count - auio.uio_resid;
3967 done:
3968 	fdrop(fp);
3969 	return (error);
3970 }
3971 
3972 /*
3973  * getdirentries_args(int fd, char *buf, u_int conut, long *basep)
3974  *
3975  * Read a block of directory entries in a file system independent format.
3976  */
3977 int
3978 sys_getdirentries(struct getdirentries_args *uap)
3979 {
3980 	long base;
3981 	int error;
3982 
3983 	error = kern_getdirentries(uap->fd, uap->buf, uap->count, &base,
3984 				   &uap->sysmsg_result, UIO_USERSPACE);
3985 
3986 	if (error == 0 && uap->basep)
3987 		error = copyout(&base, uap->basep, sizeof(*uap->basep));
3988 	return (error);
3989 }
3990 
3991 /*
3992  * getdents_args(int fd, char *buf, size_t count)
3993  */
3994 int
3995 sys_getdents(struct getdents_args *uap)
3996 {
3997 	int error;
3998 
3999 	error = kern_getdirentries(uap->fd, uap->buf, uap->count, NULL,
4000 				   &uap->sysmsg_result, UIO_USERSPACE);
4001 
4002 	return (error);
4003 }
4004 
4005 /*
4006  * Set the mode mask for creation of filesystem nodes.
4007  *
4008  * umask(int newmask)
4009  */
4010 int
4011 sys_umask(struct umask_args *uap)
4012 {
4013 	struct thread *td = curthread;
4014 	struct proc *p = td->td_proc;
4015 	struct filedesc *fdp;
4016 
4017 	fdp = p->p_fd;
4018 	uap->sysmsg_result = fdp->fd_cmask;
4019 	fdp->fd_cmask = uap->newmask & ALLPERMS;
4020 	return (0);
4021 }
4022 
4023 /*
4024  * revoke(char *path)
4025  *
4026  * Void all references to file by ripping underlying filesystem
4027  * away from vnode.
4028  */
4029 int
4030 sys_revoke(struct revoke_args *uap)
4031 {
4032 	struct nlookupdata nd;
4033 	struct vattr vattr;
4034 	struct vnode *vp;
4035 	struct ucred *cred;
4036 	int error;
4037 
4038 	vp = NULL;
4039 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4040 	if (error == 0)
4041 		error = nlookup(&nd);
4042 	if (error == 0)
4043 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
4044 	cred = crhold(nd.nl_cred);
4045 	nlookup_done(&nd);
4046 	if (error == 0) {
4047 		if (error == 0)
4048 			error = VOP_GETATTR(vp, &vattr);
4049 		if (error == 0 && cred->cr_uid != vattr.va_uid)
4050 			error = priv_check_cred(cred, PRIV_VFS_REVOKE, 0);
4051 		if (error == 0 && (vp->v_type == VCHR || vp->v_type == VBLK)) {
4052 			if (vcount(vp) > 0)
4053 				error = vrevoke(vp, cred);
4054 		} else if (error == 0) {
4055 			error = vrevoke(vp, cred);
4056 		}
4057 		vrele(vp);
4058 	}
4059 	if (cred)
4060 		crfree(cred);
4061 	return (error);
4062 }
4063 
4064 /*
4065  * getfh_args(char *fname, fhandle_t *fhp)
4066  *
4067  * Get (NFS) file handle
4068  *
4069  * NOTE: We use the fsid of the covering mount, even if it is a nullfs
4070  * mount.  This allows nullfs mounts to be explicitly exported.
4071  *
4072  * WARNING: nullfs mounts of HAMMER PFS ROOTs are safe.
4073  *
4074  * 	    nullfs mounts of subdirectories are not safe.  That is, it will
4075  *	    work, but you do not really have protection against access to
4076  *	    the related parent directories.
4077  */
4078 int
4079 sys_getfh(struct getfh_args *uap)
4080 {
4081 	struct thread *td = curthread;
4082 	struct nlookupdata nd;
4083 	fhandle_t fh;
4084 	struct vnode *vp;
4085 	struct mount *mp;
4086 	int error;
4087 
4088 	/*
4089 	 * Must be super user
4090 	 */
4091 	if ((error = priv_check(td, PRIV_ROOT)) != 0)
4092 		return (error);
4093 
4094 	vp = NULL;
4095 	error = nlookup_init(&nd, uap->fname, UIO_USERSPACE, NLC_FOLLOW);
4096 	if (error == 0)
4097 		error = nlookup(&nd);
4098 	if (error == 0)
4099 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
4100 	mp = nd.nl_nch.mount;
4101 	nlookup_done(&nd);
4102 	if (error == 0) {
4103 		bzero(&fh, sizeof(fh));
4104 		fh.fh_fsid = mp->mnt_stat.f_fsid;
4105 		error = VFS_VPTOFH(vp, &fh.fh_fid);
4106 		vput(vp);
4107 		if (error == 0)
4108 			error = copyout(&fh, uap->fhp, sizeof(fh));
4109 	}
4110 	return (error);
4111 }
4112 
4113 /*
4114  * fhopen_args(const struct fhandle *u_fhp, int flags)
4115  *
4116  * syscall for the rpc.lockd to use to translate a NFS file handle into
4117  * an open descriptor.
4118  *
4119  * warning: do not remove the priv_check() call or this becomes one giant
4120  * security hole.
4121  */
4122 int
4123 sys_fhopen(struct fhopen_args *uap)
4124 {
4125 	struct thread *td = curthread;
4126 	struct filedesc *fdp = td->td_proc->p_fd;
4127 	struct mount *mp;
4128 	struct vnode *vp;
4129 	struct fhandle fhp;
4130 	struct vattr vat;
4131 	struct vattr *vap = &vat;
4132 	struct flock lf;
4133 	int fmode, mode, error, type;
4134 	struct file *nfp;
4135 	struct file *fp;
4136 	int indx;
4137 
4138 	/*
4139 	 * Must be super user
4140 	 */
4141 	error = priv_check(td, PRIV_ROOT);
4142 	if (error)
4143 		return (error);
4144 
4145 	fmode = FFLAGS(uap->flags);
4146 
4147 	/*
4148 	 * Why not allow a non-read/write open for our lockd?
4149 	 */
4150 	if (((fmode & (FREAD | FWRITE)) == 0) || (fmode & O_CREAT))
4151 		return (EINVAL);
4152 	error = copyin(uap->u_fhp, &fhp, sizeof(fhp));
4153 	if (error)
4154 		return(error);
4155 
4156 	/*
4157 	 * Find the mount point
4158 	 */
4159 	mp = vfs_getvfs(&fhp.fh_fsid);
4160 	if (mp == NULL) {
4161 		error = ESTALE;
4162 		goto  done;
4163 	}
4164 	/* now give me my vnode, it gets returned to me locked */
4165 	error = VFS_FHTOVP(mp, NULL, &fhp.fh_fid, &vp);
4166 	if (error)
4167 		goto done;
4168  	/*
4169 	 * from now on we have to make sure not
4170 	 * to forget about the vnode
4171 	 * any error that causes an abort must vput(vp)
4172 	 * just set error = err and 'goto bad;'.
4173 	 */
4174 
4175 	/*
4176 	 * from vn_open
4177 	 */
4178 	if (vp->v_type == VLNK) {
4179 		error = EMLINK;
4180 		goto bad;
4181 	}
4182 	if (vp->v_type == VSOCK) {
4183 		error = EOPNOTSUPP;
4184 		goto bad;
4185 	}
4186 	mode = 0;
4187 	if (fmode & (FWRITE | O_TRUNC)) {
4188 		if (vp->v_type == VDIR) {
4189 			error = EISDIR;
4190 			goto bad;
4191 		}
4192 		error = vn_writechk(vp, NULL);
4193 		if (error)
4194 			goto bad;
4195 		mode |= VWRITE;
4196 	}
4197 	if (fmode & FREAD)
4198 		mode |= VREAD;
4199 	if (mode) {
4200 		error = VOP_ACCESS(vp, mode, td->td_ucred);
4201 		if (error)
4202 			goto bad;
4203 	}
4204 	if (fmode & O_TRUNC) {
4205 		vn_unlock(vp);				/* XXX */
4206 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);	/* XXX */
4207 		VATTR_NULL(vap);
4208 		vap->va_size = 0;
4209 		error = VOP_SETATTR(vp, vap, td->td_ucred);
4210 		if (error)
4211 			goto bad;
4212 	}
4213 
4214 	/*
4215 	 * VOP_OPEN needs the file pointer so it can potentially override
4216 	 * it.
4217 	 *
4218 	 * WARNING! no f_nchandle will be associated when fhopen()ing a
4219 	 * directory.  XXX
4220 	 */
4221 	if ((error = falloc(td->td_lwp, &nfp, &indx)) != 0)
4222 		goto bad;
4223 	fp = nfp;
4224 
4225 	error = VOP_OPEN(vp, fmode, td->td_ucred, fp);
4226 	if (error) {
4227 		/*
4228 		 * setting f_ops this way prevents VOP_CLOSE from being
4229 		 * called or fdrop() releasing the vp from v_data.   Since
4230 		 * the VOP_OPEN failed we don't want to VOP_CLOSE.
4231 		 */
4232 		fp->f_ops = &badfileops;
4233 		fp->f_data = NULL;
4234 		goto bad_drop;
4235 	}
4236 
4237 	/*
4238 	 * The fp is given its own reference, we still have our ref and lock.
4239 	 *
4240 	 * Assert that all regular files must be created with a VM object.
4241 	 */
4242 	if (vp->v_type == VREG && vp->v_object == NULL) {
4243 		kprintf("fhopen: regular file did not have VM object: %p\n", vp);
4244 		goto bad_drop;
4245 	}
4246 
4247 	/*
4248 	 * The open was successful.  Handle any locking requirements.
4249 	 */
4250 	if (fmode & (O_EXLOCK | O_SHLOCK)) {
4251 		lf.l_whence = SEEK_SET;
4252 		lf.l_start = 0;
4253 		lf.l_len = 0;
4254 		if (fmode & O_EXLOCK)
4255 			lf.l_type = F_WRLCK;
4256 		else
4257 			lf.l_type = F_RDLCK;
4258 		if (fmode & FNONBLOCK)
4259 			type = 0;
4260 		else
4261 			type = F_WAIT;
4262 		vn_unlock(vp);
4263 		if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0) {
4264 			/*
4265 			 * release our private reference.
4266 			 */
4267 			fsetfd(fdp, NULL, indx);
4268 			fdrop(fp);
4269 			vrele(vp);
4270 			goto done;
4271 		}
4272 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
4273 		fp->f_flag |= FHASLOCK;
4274 	}
4275 
4276 	/*
4277 	 * Clean up.  Associate the file pointer with the previously
4278 	 * reserved descriptor and return it.
4279 	 */
4280 	vput(vp);
4281 	fsetfd(fdp, fp, indx);
4282 	fdrop(fp);
4283 	uap->sysmsg_result = indx;
4284 	return (0);
4285 
4286 bad_drop:
4287 	fsetfd(fdp, NULL, indx);
4288 	fdrop(fp);
4289 bad:
4290 	vput(vp);
4291 done:
4292 	return (error);
4293 }
4294 
4295 /*
4296  * fhstat_args(struct fhandle *u_fhp, struct stat *sb)
4297  */
4298 int
4299 sys_fhstat(struct fhstat_args *uap)
4300 {
4301 	struct thread *td = curthread;
4302 	struct stat sb;
4303 	fhandle_t fh;
4304 	struct mount *mp;
4305 	struct vnode *vp;
4306 	int error;
4307 
4308 	/*
4309 	 * Must be super user
4310 	 */
4311 	error = priv_check(td, PRIV_ROOT);
4312 	if (error)
4313 		return (error);
4314 
4315 	error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t));
4316 	if (error)
4317 		return (error);
4318 
4319 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL)
4320 		error = ESTALE;
4321 	if (error == 0) {
4322 		if ((error = VFS_FHTOVP(mp, NULL, &fh.fh_fid, &vp)) == 0) {
4323 			error = vn_stat(vp, &sb, td->td_ucred);
4324 			vput(vp);
4325 		}
4326 	}
4327 	if (error == 0)
4328 		error = copyout(&sb, uap->sb, sizeof(sb));
4329 	return (error);
4330 }
4331 
4332 /*
4333  * fhstatfs_args(struct fhandle *u_fhp, struct statfs *buf)
4334  */
4335 int
4336 sys_fhstatfs(struct fhstatfs_args *uap)
4337 {
4338 	struct thread *td = curthread;
4339 	struct proc *p = td->td_proc;
4340 	struct statfs *sp;
4341 	struct mount *mp;
4342 	struct vnode *vp;
4343 	struct statfs sb;
4344 	char *fullpath, *freepath;
4345 	fhandle_t fh;
4346 	int error;
4347 
4348 	/*
4349 	 * Must be super user
4350 	 */
4351 	if ((error = priv_check(td, PRIV_ROOT)))
4352 		return (error);
4353 
4354 	if ((error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t))) != 0)
4355 		return (error);
4356 
4357 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL) {
4358 		error = ESTALE;
4359 		goto done;
4360 	}
4361 	if (p != NULL && !chroot_visible_mnt(mp, p)) {
4362 		error = ESTALE;
4363 		goto done;
4364 	}
4365 
4366 	if ((error = VFS_FHTOVP(mp, NULL, &fh.fh_fid, &vp)) != 0)
4367 		goto done;
4368 	mp = vp->v_mount;
4369 	sp = &mp->mnt_stat;
4370 	vput(vp);
4371 	if ((error = VFS_STATFS(mp, sp, td->td_ucred)) != 0)
4372 		goto done;
4373 
4374 	error = mount_path(p, mp, &fullpath, &freepath);
4375 	if (error)
4376 		goto done;
4377 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
4378 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
4379 	kfree(freepath, M_TEMP);
4380 
4381 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
4382 	if (priv_check(td, PRIV_ROOT)) {
4383 		bcopy(sp, &sb, sizeof(sb));
4384 		sb.f_fsid.val[0] = sb.f_fsid.val[1] = 0;
4385 		sp = &sb;
4386 	}
4387 	error = copyout(sp, uap->buf, sizeof(*sp));
4388 done:
4389 	return (error);
4390 }
4391 
4392 /*
4393  * fhstatvfs_args(struct fhandle *u_fhp, struct statvfs *buf)
4394  */
4395 int
4396 sys_fhstatvfs(struct fhstatvfs_args *uap)
4397 {
4398 	struct thread *td = curthread;
4399 	struct proc *p = td->td_proc;
4400 	struct statvfs *sp;
4401 	struct mount *mp;
4402 	struct vnode *vp;
4403 	fhandle_t fh;
4404 	int error;
4405 
4406 	/*
4407 	 * Must be super user
4408 	 */
4409 	if ((error = priv_check(td, PRIV_ROOT)))
4410 		return (error);
4411 
4412 	if ((error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t))) != 0)
4413 		return (error);
4414 
4415 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL) {
4416 		error = ESTALE;
4417 		goto done;
4418 	}
4419 	if (p != NULL && !chroot_visible_mnt(mp, p)) {
4420 		error = ESTALE;
4421 		goto done;
4422 	}
4423 
4424 	if ((error = VFS_FHTOVP(mp, NULL, &fh.fh_fid, &vp)))
4425 		goto done;
4426 	mp = vp->v_mount;
4427 	sp = &mp->mnt_vstat;
4428 	vput(vp);
4429 	if ((error = VFS_STATVFS(mp, sp, td->td_ucred)) != 0)
4430 		goto done;
4431 
4432 	sp->f_flag = 0;
4433 	if (mp->mnt_flag & MNT_RDONLY)
4434 		sp->f_flag |= ST_RDONLY;
4435 	if (mp->mnt_flag & MNT_NOSUID)
4436 		sp->f_flag |= ST_NOSUID;
4437 	error = copyout(sp, uap->buf, sizeof(*sp));
4438 done:
4439 	return (error);
4440 }
4441 
4442 
4443 /*
4444  * Syscall to push extended attribute configuration information into the
4445  * VFS.  Accepts a path, which it converts to a mountpoint, as well as
4446  * a command (int cmd), and attribute name and misc data.  For now, the
4447  * attribute name is left in userspace for consumption by the VFS_op.
4448  * It will probably be changed to be copied into sysspace by the
4449  * syscall in the future, once issues with various consumers of the
4450  * attribute code have raised their hands.
4451  *
4452  * Currently this is used only by UFS Extended Attributes.
4453  */
4454 int
4455 sys_extattrctl(struct extattrctl_args *uap)
4456 {
4457 	struct nlookupdata nd;
4458 	struct vnode *vp;
4459 	char attrname[EXTATTR_MAXNAMELEN];
4460 	int error;
4461 	size_t size;
4462 
4463 	attrname[0] = 0;
4464 	vp = NULL;
4465 	error = 0;
4466 
4467 	if (error == 0 && uap->filename) {
4468 		error = nlookup_init(&nd, uap->filename, UIO_USERSPACE,
4469 				     NLC_FOLLOW);
4470 		if (error == 0)
4471 			error = nlookup(&nd);
4472 		if (error == 0)
4473 			error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
4474 		nlookup_done(&nd);
4475 	}
4476 
4477 	if (error == 0 && uap->attrname) {
4478 		error = copyinstr(uap->attrname, attrname, EXTATTR_MAXNAMELEN,
4479 				  &size);
4480 	}
4481 
4482 	if (error == 0) {
4483 		error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4484 		if (error == 0)
4485 			error = nlookup(&nd);
4486 		if (error == 0)
4487 			error = ncp_writechk(&nd.nl_nch);
4488 		if (error == 0) {
4489 			error = VFS_EXTATTRCTL(nd.nl_nch.mount, uap->cmd, vp,
4490 					       uap->attrnamespace,
4491 					       uap->attrname, nd.nl_cred);
4492 		}
4493 		nlookup_done(&nd);
4494 	}
4495 
4496 	return (error);
4497 }
4498 
4499 /*
4500  * Syscall to get a named extended attribute on a file or directory.
4501  */
4502 int
4503 sys_extattr_set_file(struct extattr_set_file_args *uap)
4504 {
4505 	char attrname[EXTATTR_MAXNAMELEN];
4506 	struct nlookupdata nd;
4507 	struct vnode *vp;
4508 	struct uio auio;
4509 	struct iovec aiov;
4510 	int error;
4511 
4512 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
4513 	if (error)
4514 		return (error);
4515 
4516 	vp = NULL;
4517 
4518 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4519 	if (error == 0)
4520 		error = nlookup(&nd);
4521 	if (error == 0)
4522 		error = ncp_writechk(&nd.nl_nch);
4523 	if (error == 0)
4524 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
4525 	if (error) {
4526 		nlookup_done(&nd);
4527 		return (error);
4528 	}
4529 
4530 	bzero(&auio, sizeof(auio));
4531 	aiov.iov_base = uap->data;
4532 	aiov.iov_len = uap->nbytes;
4533 	auio.uio_iov = &aiov;
4534 	auio.uio_iovcnt = 1;
4535 	auio.uio_offset = 0;
4536 	auio.uio_resid = uap->nbytes;
4537 	auio.uio_rw = UIO_WRITE;
4538 	auio.uio_td = curthread;
4539 
4540 	error = VOP_SETEXTATTR(vp, uap->attrnamespace, attrname,
4541 			       &auio, nd.nl_cred);
4542 
4543 	vput(vp);
4544 	nlookup_done(&nd);
4545 	return (error);
4546 }
4547 
4548 /*
4549  * Syscall to get a named extended attribute on a file or directory.
4550  */
4551 int
4552 sys_extattr_get_file(struct extattr_get_file_args *uap)
4553 {
4554 	char attrname[EXTATTR_MAXNAMELEN];
4555 	struct nlookupdata nd;
4556 	struct uio auio;
4557 	struct iovec aiov;
4558 	struct vnode *vp;
4559 	int error;
4560 
4561 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
4562 	if (error)
4563 		return (error);
4564 
4565 	vp = NULL;
4566 
4567 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4568 	if (error == 0)
4569 		error = nlookup(&nd);
4570 	if (error == 0)
4571 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
4572 	if (error) {
4573 		nlookup_done(&nd);
4574 		return (error);
4575 	}
4576 
4577 	bzero(&auio, sizeof(auio));
4578 	aiov.iov_base = uap->data;
4579 	aiov.iov_len = uap->nbytes;
4580 	auio.uio_iov = &aiov;
4581 	auio.uio_iovcnt = 1;
4582 	auio.uio_offset = 0;
4583 	auio.uio_resid = uap->nbytes;
4584 	auio.uio_rw = UIO_READ;
4585 	auio.uio_td = curthread;
4586 
4587 	error = VOP_GETEXTATTR(vp, uap->attrnamespace, attrname,
4588 				&auio, nd.nl_cred);
4589 	uap->sysmsg_result = uap->nbytes - auio.uio_resid;
4590 
4591 	vput(vp);
4592 	nlookup_done(&nd);
4593 	return(error);
4594 }
4595 
4596 /*
4597  * Syscall to delete a named extended attribute from a file or directory.
4598  * Accepts attribute name.  The real work happens in VOP_SETEXTATTR().
4599  */
4600 int
4601 sys_extattr_delete_file(struct extattr_delete_file_args *uap)
4602 {
4603 	char attrname[EXTATTR_MAXNAMELEN];
4604 	struct nlookupdata nd;
4605 	struct vnode *vp;
4606 	int error;
4607 
4608 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
4609 	if (error)
4610 		return(error);
4611 
4612 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
4613 	if (error == 0)
4614 		error = nlookup(&nd);
4615 	if (error == 0)
4616 		error = ncp_writechk(&nd.nl_nch);
4617 	if (error == 0) {
4618 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
4619 		if (error == 0) {
4620 			error = VOP_SETEXTATTR(vp, uap->attrnamespace,
4621 					       attrname, NULL, nd.nl_cred);
4622 			vput(vp);
4623 		}
4624 	}
4625 	nlookup_done(&nd);
4626 	return(error);
4627 }
4628 
4629 /*
4630  * Determine if the mount is visible to the process.
4631  */
4632 static int
4633 chroot_visible_mnt(struct mount *mp, struct proc *p)
4634 {
4635 	struct nchandle nch;
4636 
4637 	/*
4638 	 * Traverse from the mount point upwards.  If we hit the process
4639 	 * root then the mount point is visible to the process.
4640 	 */
4641 	nch = mp->mnt_ncmountpt;
4642 	while (nch.ncp) {
4643 		if (nch.mount == p->p_fd->fd_nrdir.mount &&
4644 		    nch.ncp == p->p_fd->fd_nrdir.ncp) {
4645 			return(1);
4646 		}
4647 		if (nch.ncp == nch.mount->mnt_ncmountpt.ncp) {
4648 			nch = nch.mount->mnt_ncmounton;
4649 		} else {
4650 			nch.ncp = nch.ncp->nc_parent;
4651 		}
4652 	}
4653 
4654 	/*
4655 	 * If the mount point is not visible to the process, but the
4656 	 * process root is in a subdirectory of the mount, return
4657 	 * TRUE anyway.
4658 	 */
4659 	if (p->p_fd->fd_nrdir.mount == mp)
4660 		return(1);
4661 
4662 	return(0);
4663 }
4664 
4665