xref: /dragonfly/sys/kern/vfs_syscalls.c (revision 23265324)
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  * $DragonFly: src/sys/kern/vfs_syscalls.c,v 1.114 2007/02/18 07:12:19 swildner Exp $
41  */
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/buf.h>
46 #include <sys/conf.h>
47 #include <sys/sysent.h>
48 #include <sys/malloc.h>
49 #include <sys/mount.h>
50 #include <sys/mountctl.h>
51 #include <sys/sysproto.h>
52 #include <sys/filedesc.h>
53 #include <sys/kernel.h>
54 #include <sys/fcntl.h>
55 #include <sys/file.h>
56 #include <sys/linker.h>
57 #include <sys/stat.h>
58 #include <sys/unistd.h>
59 #include <sys/vnode.h>
60 #include <sys/proc.h>
61 #include <sys/namei.h>
62 #include <sys/nlookup.h>
63 #include <sys/dirent.h>
64 #include <sys/extattr.h>
65 #include <sys/spinlock.h>
66 #include <sys/kern_syscall.h>
67 #include <sys/objcache.h>
68 #include <sys/sysctl.h>
69 #include <sys/file2.h>
70 #include <sys/spinlock2.h>
71 
72 #include <vm/vm.h>
73 #include <vm/vm_object.h>
74 #include <vm/vm_page.h>
75 
76 #include <machine/limits.h>
77 #include <machine/stdarg.h>
78 
79 #include <vfs/union/union.h>
80 
81 static void mount_warning(struct mount *mp, const char *ctl, ...);
82 static int mount_path(struct proc *p, struct mount *mp, char **rb, char **fb);
83 static int checkvp_chdir (struct vnode *vn, struct thread *td);
84 static void checkdirs (struct nchandle *old_nch, struct nchandle *new_nch);
85 static int chroot_refuse_vdir_fds (struct filedesc *fdp);
86 static int chroot_visible_mnt(struct mount *mp, struct proc *p);
87 static int getutimes (const struct timeval *, struct timespec *);
88 static int setfown (struct vnode *, uid_t, gid_t);
89 static int setfmode (struct vnode *, int);
90 static int setfflags (struct vnode *, int);
91 static int setutimes (struct vnode *, const struct timespec *, int);
92 static int	usermount = 0;	/* if 1, non-root can mount fs. */
93 
94 int (*union_dircheckp) (struct thread *, struct vnode **, struct file *);
95 
96 SYSCTL_INT(_vfs, OID_AUTO, usermount, CTLFLAG_RW, &usermount, 0, "");
97 
98 /*
99  * Virtual File System System Calls
100  */
101 
102 /*
103  * Mount a file system.
104  */
105 /*
106  * mount_args(char *type, char *path, int flags, caddr_t data)
107  */
108 /* ARGSUSED */
109 int
110 sys_mount(struct mount_args *uap)
111 {
112 	struct thread *td = curthread;
113 	struct proc *p = td->td_proc;
114 	struct vnode *vp;
115 	struct nchandle nch;
116 	struct mount *mp;
117 	struct vfsconf *vfsp;
118 	int error, flag = 0, flag2 = 0;
119 	int hasmount;
120 	struct vattr va;
121 	struct nlookupdata nd;
122 	char fstypename[MFSNAMELEN];
123 	struct ucred *cred = p->p_ucred;
124 
125 	KKASSERT(p);
126 	if (cred->cr_prison != NULL)
127 		return (EPERM);
128 	if (usermount == 0 && (error = suser(td)))
129 		return (error);
130 	/*
131 	 * Do not allow NFS export by non-root users.
132 	 */
133 	if (uap->flags & MNT_EXPORTED) {
134 		error = suser(td);
135 		if (error)
136 			return (error);
137 	}
138 	/*
139 	 * Silently enforce MNT_NOSUID and MNT_NODEV for non-root users
140 	 */
141 	if (suser(td))
142 		uap->flags |= MNT_NOSUID | MNT_NODEV;
143 
144 	/*
145 	 * Lookup the requested path and extract the nch and vnode.
146 	 */
147 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
148 	if (error == 0) {
149 		if ((error = nlookup(&nd)) == 0) {
150 			if (nd.nl_nch.ncp->nc_vp == NULL)
151 				error = ENOENT;
152 		}
153 	}
154 	if (error) {
155 		nlookup_done(&nd);
156 		return (error);
157 	}
158 
159 	/*
160 	 * Extract the locked+refd ncp and cleanup the nd structure
161 	 */
162 	nch = nd.nl_nch;
163 	cache_zero(&nd.nl_nch);
164 	nlookup_done(&nd);
165 
166 	if ((nch.ncp->nc_flag & NCF_ISMOUNTPT) && cache_findmount(&nch))
167 		hasmount = 1;
168 	else
169 		hasmount = 0;
170 
171 
172 	/*
173 	 * now we have the locked ref'd nch and unreferenced vnode.
174 	 */
175 	vp = nch.ncp->nc_vp;
176 	if ((error = vget(vp, LK_EXCLUSIVE)) != 0) {
177 		cache_put(&nch);
178 		return (error);
179 	}
180 	cache_unlock(&nch);
181 
182 	/*
183 	 * Now we have an unlocked ref'd nch and a locked ref'd vp
184 	 */
185 	if (uap->flags & MNT_UPDATE) {
186 		if ((vp->v_flag & VROOT) == 0) {
187 			cache_drop(&nch);
188 			vput(vp);
189 			return (EINVAL);
190 		}
191 		mp = vp->v_mount;
192 		flag = mp->mnt_flag;
193 		flag2 = mp->mnt_kern_flag;
194 		/*
195 		 * We only allow the filesystem to be reloaded if it
196 		 * is currently mounted read-only.
197 		 */
198 		if ((uap->flags & MNT_RELOAD) &&
199 		    ((mp->mnt_flag & MNT_RDONLY) == 0)) {
200 			cache_drop(&nch);
201 			vput(vp);
202 			return (EOPNOTSUPP);	/* Needs translation */
203 		}
204 		/*
205 		 * Only root, or the user that did the original mount is
206 		 * permitted to update it.
207 		 */
208 		if (mp->mnt_stat.f_owner != cred->cr_uid &&
209 		    (error = suser(td))) {
210 			cache_drop(&nch);
211 			vput(vp);
212 			return (error);
213 		}
214 		if (vfs_busy(mp, LK_NOWAIT)) {
215 			cache_drop(&nch);
216 			vput(vp);
217 			return (EBUSY);
218 		}
219 		if ((vp->v_flag & VMOUNT) != 0 || hasmount) {
220 			cache_drop(&nch);
221 			vfs_unbusy(mp);
222 			vput(vp);
223 			return (EBUSY);
224 		}
225 		vp->v_flag |= VMOUNT;
226 		mp->mnt_flag |=
227 		    uap->flags & (MNT_RELOAD | MNT_FORCE | MNT_UPDATE);
228 		vn_unlock(vp);
229 		goto update;
230 	}
231 	/*
232 	 * If the user is not root, ensure that they own the directory
233 	 * onto which we are attempting to mount.
234 	 */
235 	if ((error = VOP_GETATTR(vp, &va)) ||
236 	    (va.va_uid != cred->cr_uid && (error = suser(td)))) {
237 		cache_drop(&nch);
238 		vput(vp);
239 		return (error);
240 	}
241 	if ((error = vinvalbuf(vp, V_SAVE, 0, 0)) != 0) {
242 		cache_drop(&nch);
243 		vput(vp);
244 		return (error);
245 	}
246 	if (vp->v_type != VDIR) {
247 		cache_drop(&nch);
248 		vput(vp);
249 		return (ENOTDIR);
250 	}
251 	if ((error = copyinstr(uap->type, fstypename, MFSNAMELEN, NULL)) != 0) {
252 		cache_drop(&nch);
253 		vput(vp);
254 		return (error);
255 	}
256 	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
257 		if (!strcmp(vfsp->vfc_name, fstypename))
258 			break;
259 	}
260 	if (vfsp == NULL) {
261 		linker_file_t lf;
262 
263 		/* Only load modules for root (very important!) */
264 		if ((error = suser(td)) != 0) {
265 			cache_drop(&nch);
266 			vput(vp);
267 			return error;
268 		}
269 		error = linker_load_file(fstypename, &lf);
270 		if (error || lf == NULL) {
271 			cache_drop(&nch);
272 			vput(vp);
273 			if (lf == NULL)
274 				error = ENODEV;
275 			return error;
276 		}
277 		lf->userrefs++;
278 		/* lookup again, see if the VFS was loaded */
279 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
280 			if (!strcmp(vfsp->vfc_name, fstypename))
281 				break;
282 		}
283 		if (vfsp == NULL) {
284 			lf->userrefs--;
285 			linker_file_unload(lf);
286 			cache_drop(&nch);
287 			vput(vp);
288 			return (ENODEV);
289 		}
290 	}
291 	if ((vp->v_flag & VMOUNT) != 0 || hasmount) {
292 		cache_drop(&nch);
293 		vput(vp);
294 		return (EBUSY);
295 	}
296 	vp->v_flag |= VMOUNT;
297 
298 	/*
299 	 * Allocate and initialize the filesystem.
300 	 */
301 	mp = kmalloc(sizeof(struct mount), M_MOUNT, M_ZERO|M_WAITOK);
302 	TAILQ_INIT(&mp->mnt_nvnodelist);
303 	TAILQ_INIT(&mp->mnt_reservedvnlist);
304 	TAILQ_INIT(&mp->mnt_jlist);
305 	mp->mnt_nvnodelistsize = 0;
306 	lockinit(&mp->mnt_lock, "vfslock", 0, 0);
307 	vfs_busy(mp, LK_NOWAIT);
308 	mp->mnt_op = vfsp->vfc_vfsops;
309 	mp->mnt_vfc = vfsp;
310 	vfsp->vfc_refcount++;
311 	mp->mnt_stat.f_type = vfsp->vfc_typenum;
312 	mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
313 	strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
314 	mp->mnt_stat.f_owner = cred->cr_uid;
315 	mp->mnt_iosize_max = DFLTPHYS;
316 	vn_unlock(vp);
317 update:
318 	/*
319 	 * Set the mount level flags.
320 	 */
321 	if (uap->flags & MNT_RDONLY)
322 		mp->mnt_flag |= MNT_RDONLY;
323 	else if (mp->mnt_flag & MNT_RDONLY)
324 		mp->mnt_kern_flag |= MNTK_WANTRDWR;
325 	mp->mnt_flag &=~ (MNT_NOSUID | MNT_NOEXEC | MNT_NODEV |
326 	    MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_NOATIME |
327 	    MNT_NOSYMFOLLOW | MNT_IGNORE |
328 	    MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR);
329 	mp->mnt_flag |= uap->flags & (MNT_NOSUID | MNT_NOEXEC |
330 	    MNT_NODEV | MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_FORCE |
331 	    MNT_NOSYMFOLLOW | MNT_IGNORE |
332 	    MNT_NOATIME | MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR);
333 	/*
334 	 * Mount the filesystem.
335 	 * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
336 	 * get.
337 	 */
338 	error = VFS_MOUNT(mp, uap->path, uap->data, cred);
339 	if (mp->mnt_flag & MNT_UPDATE) {
340 		if (mp->mnt_kern_flag & MNTK_WANTRDWR)
341 			mp->mnt_flag &= ~MNT_RDONLY;
342 		mp->mnt_flag &=~ (MNT_UPDATE | MNT_RELOAD | MNT_FORCE);
343 		mp->mnt_kern_flag &=~ MNTK_WANTRDWR;
344 		if (error) {
345 			mp->mnt_flag = flag;
346 			mp->mnt_kern_flag = flag2;
347 		}
348 		vfs_unbusy(mp);
349 		vp->v_flag &= ~VMOUNT;
350 		vrele(vp);
351 		cache_drop(&nch);
352 		return (error);
353 	}
354 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
355 	/*
356 	 * Put the new filesystem on the mount list after root.  The mount
357 	 * point gets its own mnt_ncmountpt (unless the VFS already set one
358 	 * up) which represents the root of the mount.  The lookup code
359 	 * detects the mount point going forward and checks the root of
360 	 * the mount going backwards.
361 	 *
362 	 * It is not necessary to invalidate or purge the vnode underneath
363 	 * because elements under the mount will be given their own glue
364 	 * namecache record.
365 	 */
366 	if (!error) {
367 		if (mp->mnt_ncmountpt.ncp == NULL) {
368 			/*
369 			 * allocate, then unlock, but leave the ref intact
370 			 */
371 			cache_allocroot(&mp->mnt_ncmountpt, mp, NULL);
372 			cache_unlock(&mp->mnt_ncmountpt);
373 		}
374 		mp->mnt_ncmounton = nch;		/* inherits ref */
375 		nch.ncp->nc_flag |= NCF_ISMOUNTPT;
376 
377 		/* XXX get the root of the fs and cache_setvp(mnt_ncmountpt...) */
378 		vp->v_flag &= ~VMOUNT;
379 		mountlist_insert(mp, MNTINS_LAST);
380 		checkdirs(&mp->mnt_ncmounton, &mp->mnt_ncmountpt);
381 		vn_unlock(vp);
382 		error = vfs_allocate_syncvnode(mp);
383 		vfs_unbusy(mp);
384 		error = VFS_START(mp, 0);
385 		vrele(vp);
386 	} else {
387 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
388 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
389 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
390 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
391 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
392 		vp->v_flag &= ~VMOUNT;
393 		mp->mnt_vfc->vfc_refcount--;
394 		vfs_unbusy(mp);
395 		kfree(mp, M_MOUNT);
396 		cache_drop(&nch);
397 		vput(vp);
398 	}
399 	return (error);
400 }
401 
402 /*
403  * Scan all active processes to see if any of them have a current
404  * or root directory onto which the new filesystem has just been
405  * mounted. If so, replace them with the new mount point.
406  *
407  * The passed ncp is ref'd and locked (from the mount code) and
408  * must be associated with the vnode representing the root of the
409  * mount point.
410  */
411 struct checkdirs_info {
412 	struct nchandle old_nch;
413 	struct nchandle new_nch;
414 	struct vnode *old_vp;
415 	struct vnode *new_vp;
416 };
417 
418 static int checkdirs_callback(struct proc *p, void *data);
419 
420 static void
421 checkdirs(struct nchandle *old_nch, struct nchandle *new_nch)
422 {
423 	struct checkdirs_info info;
424 	struct vnode *olddp;
425 	struct vnode *newdp;
426 	struct mount *mp;
427 
428 	/*
429 	 * If the old mount point's vnode has a usecount of 1, it is not
430 	 * being held as a descriptor anywhere.
431 	 */
432 	olddp = old_nch->ncp->nc_vp;
433 	if (olddp == NULL || olddp->v_usecount == 1)
434 		return;
435 
436 	/*
437 	 * Force the root vnode of the new mount point to be resolved
438 	 * so we can update any matching processes.
439 	 */
440 	mp = new_nch->mount;
441 	if (VFS_ROOT(mp, &newdp))
442 		panic("mount: lost mount");
443 	cache_setunresolved(new_nch);
444 	cache_setvp(new_nch, newdp);
445 
446 	/*
447 	 * Special handling of the root node
448 	 */
449 	if (rootvnode == olddp) {
450 		vref(newdp);
451 		vfs_cache_setroot(newdp, cache_hold(new_nch));
452 	}
453 
454 	/*
455 	 * Pass newdp separately so the callback does not have to access
456 	 * it via new_nch->ncp->nc_vp.
457 	 */
458 	info.old_nch = *old_nch;
459 	info.new_nch = *new_nch;
460 	info.new_vp = newdp;
461 	allproc_scan(checkdirs_callback, &info);
462 	vput(newdp);
463 }
464 
465 /*
466  * NOTE: callback is not MP safe because the scanned process's filedesc
467  * structure can be ripped out from under us, amoung other things.
468  */
469 static int
470 checkdirs_callback(struct proc *p, void *data)
471 {
472 	struct checkdirs_info *info = data;
473 	struct filedesc *fdp;
474 	struct nchandle ncdrop1;
475 	struct nchandle ncdrop2;
476 	struct vnode *vprele1;
477 	struct vnode *vprele2;
478 
479 	if ((fdp = p->p_fd) != NULL) {
480 		cache_zero(&ncdrop1);
481 		cache_zero(&ncdrop2);
482 		vprele1 = NULL;
483 		vprele2 = NULL;
484 
485 		/*
486 		 * MPUNSAFE - XXX fdp can be pulled out from under a
487 		 * foreign process.
488 		 *
489 		 * A shared filedesc is ok, we don't have to copy it
490 		 * because we are making this change globally.
491 		 */
492 		spin_lock_wr(&fdp->fd_spin);
493 		if (fdp->fd_ncdir.mount == info->old_nch.mount &&
494 		    fdp->fd_ncdir.ncp == info->old_nch.ncp) {
495 			vprele1 = fdp->fd_cdir;
496 			vref(info->new_vp);
497 			fdp->fd_cdir = info->new_vp;
498 			ncdrop1 = fdp->fd_ncdir;
499 			cache_copy(&info->new_nch, &fdp->fd_ncdir);
500 		}
501 		if (fdp->fd_nrdir.mount == info->old_nch.mount &&
502 		    fdp->fd_nrdir.ncp == info->old_nch.ncp) {
503 			vprele2 = fdp->fd_rdir;
504 			vref(info->new_vp);
505 			fdp->fd_rdir = info->new_vp;
506 			ncdrop2 = fdp->fd_nrdir;
507 			cache_copy(&info->new_nch, &fdp->fd_nrdir);
508 		}
509 		spin_unlock_wr(&fdp->fd_spin);
510 		if (ncdrop1.ncp)
511 			cache_drop(&ncdrop1);
512 		if (ncdrop2.ncp)
513 			cache_drop(&ncdrop2);
514 		if (vprele1)
515 			vrele(vprele1);
516 		if (vprele2)
517 			vrele(vprele2);
518 	}
519 	return(0);
520 }
521 
522 /*
523  * Unmount a file system.
524  *
525  * Note: unmount takes a path to the vnode mounted on as argument,
526  * not special file (as before).
527  */
528 /*
529  * umount_args(char *path, int flags)
530  */
531 /* ARGSUSED */
532 int
533 sys_unmount(struct unmount_args *uap)
534 {
535 	struct thread *td = curthread;
536 	struct proc *p = td->td_proc;
537 	struct mount *mp = NULL;
538 	int error;
539 	struct nlookupdata nd;
540 
541 	KKASSERT(p);
542 	if (p->p_ucred->cr_prison != NULL)
543 		return (EPERM);
544 	if (usermount == 0 && (error = suser(td)))
545 		return (error);
546 
547 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
548 	if (error == 0)
549 		error = nlookup(&nd);
550 	if (error)
551 		goto out;
552 
553 	mp = nd.nl_nch.mount;
554 
555 	/*
556 	 * Only root, or the user that did the original mount is
557 	 * permitted to unmount this filesystem.
558 	 */
559 	if ((mp->mnt_stat.f_owner != p->p_ucred->cr_uid) &&
560 	    (error = suser(td)))
561 		goto out;
562 
563 	/*
564 	 * Don't allow unmounting the root file system.
565 	 */
566 	if (mp->mnt_flag & MNT_ROOTFS) {
567 		error = EINVAL;
568 		goto out;
569 	}
570 
571 	/*
572 	 * Must be the root of the filesystem
573 	 */
574 	if (nd.nl_nch.ncp != mp->mnt_ncmountpt.ncp) {
575 		error = EINVAL;
576 		goto out;
577 	}
578 
579 out:
580 	nlookup_done(&nd);
581 	if (error)
582 		return (error);
583 	return (dounmount(mp, uap->flags));
584 }
585 
586 /*
587  * Do the actual file system unmount.
588  */
589 static int
590 dounmount_interlock(struct mount *mp)
591 {
592 	if (mp->mnt_kern_flag & MNTK_UNMOUNT)
593 		return (EBUSY);
594 	mp->mnt_kern_flag |= MNTK_UNMOUNT;
595 	return(0);
596 }
597 
598 int
599 dounmount(struct mount *mp, int flags)
600 {
601 	struct namecache *ncp;
602 	struct nchandle nch;
603 	int error;
604 	int async_flag;
605 	int lflags;
606 	int freeok = 1;
607 
608 	/*
609 	 * Exclusive access for unmounting purposes
610 	 */
611 	if ((error = mountlist_interlock(dounmount_interlock, mp)) != 0)
612 		return (error);
613 
614 	/*
615 	 * Allow filesystems to detect that a forced unmount is in progress.
616 	 */
617 	if (flags & MNT_FORCE)
618 		mp->mnt_kern_flag |= MNTK_UNMOUNTF;
619 	lflags = LK_EXCLUSIVE | ((flags & MNT_FORCE) ? 0 : LK_NOWAIT);
620 	error = lockmgr(&mp->mnt_lock, lflags);
621 	if (error) {
622 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
623 		if (mp->mnt_kern_flag & MNTK_MWAIT)
624 			wakeup(mp);
625 		return (error);
626 	}
627 
628 	if (mp->mnt_flag & MNT_EXPUBLIC)
629 		vfs_setpublicfs(NULL, NULL, NULL);
630 
631 	vfs_msync(mp, MNT_WAIT);
632 	async_flag = mp->mnt_flag & MNT_ASYNC;
633 	mp->mnt_flag &=~ MNT_ASYNC;
634 
635 	/*
636 	 * If this filesystem isn't aliasing other filesystems,
637 	 * try to invalidate any remaining namecache entries and
638 	 * check the count afterwords.
639 	 */
640 	if ((mp->mnt_kern_flag & MNTK_NCALIASED) == 0) {
641 		cache_lock(&mp->mnt_ncmountpt);
642 		cache_inval(&mp->mnt_ncmountpt, CINV_DESTROY|CINV_CHILDREN);
643 		cache_unlock(&mp->mnt_ncmountpt);
644 
645 		if ((ncp = mp->mnt_ncmountpt.ncp) != NULL &&
646 		    (ncp->nc_refs != 1 || TAILQ_FIRST(&ncp->nc_list))) {
647 
648 			if ((flags & MNT_FORCE) == 0) {
649 				error = EBUSY;
650 				mount_warning(mp, "Cannot unmount: "
651 						  "%d namecache "
652 						  "references still "
653 						  "present",
654 						  ncp->nc_refs - 1);
655 			} else {
656 				mount_warning(mp, "Forced unmount: "
657 						  "%d namecache "
658 						  "references still "
659 						  "present",
660 						  ncp->nc_refs - 1);
661 				freeok = 0;
662 			}
663 		}
664 	}
665 
666 	/*
667 	 * nchandle records ref the mount structure.  Expect a count of 1
668 	 * (our mount->mnt_ncmountpt).
669 	 */
670 	if (mp->mnt_refs != 1) {
671 		if ((flags & MNT_FORCE) == 0) {
672 			mount_warning(mp, "Cannot unmount: "
673 					  "%d process references still "
674 					  "present", mp->mnt_refs);
675 			error = EBUSY;
676 		} else {
677 			mount_warning(mp, "Forced unmount: "
678 					  "%d process references still "
679 					  "present", mp->mnt_refs);
680 			freeok = 0;
681 		}
682 	}
683 
684 	if (error == 0) {
685 		if (mp->mnt_syncer != NULL)
686 			vrele(mp->mnt_syncer);
687 		if (((mp->mnt_flag & MNT_RDONLY) ||
688 		     (error = VFS_SYNC(mp, MNT_WAIT)) == 0) ||
689 		    (flags & MNT_FORCE)) {
690 			error = VFS_UNMOUNT(mp, flags);
691 		}
692 	}
693 	if (error) {
694 		if (mp->mnt_syncer == NULL)
695 			vfs_allocate_syncvnode(mp);
696 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
697 		mp->mnt_flag |= async_flag;
698 		lockmgr(&mp->mnt_lock, LK_RELEASE);
699 		if (mp->mnt_kern_flag & MNTK_MWAIT)
700 			wakeup(mp);
701 		return (error);
702 	}
703 	/*
704 	 * Clean up any journals still associated with the mount after
705 	 * filesystem activity has ceased.
706 	 */
707 	journal_remove_all_journals(mp,
708 	    ((flags & MNT_FORCE) ? MC_JOURNAL_STOP_IMM : 0));
709 
710 	mountlist_remove(mp);
711 
712 	/*
713 	 * Remove any installed vnode ops here so the individual VFSs don't
714 	 * have to.
715 	 */
716 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
717 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
718 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
719 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
720 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
721 
722 	if (mp->mnt_ncmountpt.ncp != NULL) {
723 		nch = mp->mnt_ncmountpt;
724 		cache_zero(&mp->mnt_ncmountpt);
725 		cache_clrmountpt(&nch);
726 		cache_drop(&nch);
727 	}
728 	if (mp->mnt_ncmounton.ncp != NULL) {
729 		nch = mp->mnt_ncmounton;
730 		cache_zero(&mp->mnt_ncmounton);
731 		cache_clrmountpt(&nch);
732 		cache_drop(&nch);
733 	}
734 
735 	mp->mnt_vfc->vfc_refcount--;
736 	if (!TAILQ_EMPTY(&mp->mnt_nvnodelist))
737 		panic("unmount: dangling vnode");
738 	lockmgr(&mp->mnt_lock, LK_RELEASE);
739 	if (mp->mnt_kern_flag & MNTK_MWAIT)
740 		wakeup(mp);
741 	if (freeok)
742 		kfree(mp, M_MOUNT);
743 	return (0);
744 }
745 
746 static
747 void
748 mount_warning(struct mount *mp, const char *ctl, ...)
749 {
750 	char *ptr;
751 	char *buf;
752 	__va_list va;
753 
754 	__va_start(va, ctl);
755 	if (cache_fullpath(NULL, &mp->mnt_ncmounton, &ptr, &buf) == 0) {
756 		kprintf("unmount(%s): ", ptr);
757 		kvprintf(ctl, va);
758 		kprintf("\n");
759 		kfree(buf, M_TEMP);
760 	} else {
761 		kprintf("unmount(%p): ", mp);
762 		kvprintf(ctl, va);
763 		kprintf("\n");
764 	}
765 	__va_end(va);
766 }
767 
768 /*
769  * Shim cache_fullpath() to handle the case where a process is chrooted into
770  * a subdirectory of a mount.  In this case if the root mount matches the
771  * process root directory's mount we have to specify the process's root
772  * directory instead of the mount point, because the mount point might
773  * be above the root directory.
774  */
775 static
776 int
777 mount_path(struct proc *p, struct mount *mp, char **rb, char **fb)
778 {
779 	struct nchandle *nch;
780 
781 	if (p && p->p_fd->fd_nrdir.mount == mp)
782 		nch = &p->p_fd->fd_nrdir;
783 	else
784 		nch = &mp->mnt_ncmountpt;
785 	return(cache_fullpath(p, nch, rb, fb));
786 }
787 
788 /*
789  * Sync each mounted filesystem.
790  */
791 
792 #ifdef DEBUG
793 static int syncprt = 0;
794 SYSCTL_INT(_debug, OID_AUTO, syncprt, CTLFLAG_RW, &syncprt, 0, "");
795 #endif /* DEBUG */
796 
797 static int sync_callback(struct mount *mp, void *data);
798 
799 /* ARGSUSED */
800 int
801 sys_sync(struct sync_args *uap)
802 {
803 	mountlist_scan(sync_callback, NULL, MNTSCAN_FORWARD);
804 #ifdef DEBUG
805 	/*
806 	 * print out buffer pool stat information on each sync() call.
807 	 */
808 	if (syncprt)
809 		vfs_bufstats();
810 #endif /* DEBUG */
811 	return (0);
812 }
813 
814 static
815 int
816 sync_callback(struct mount *mp, void *data __unused)
817 {
818 	int asyncflag;
819 
820 	if ((mp->mnt_flag & MNT_RDONLY) == 0) {
821 		asyncflag = mp->mnt_flag & MNT_ASYNC;
822 		mp->mnt_flag &= ~MNT_ASYNC;
823 		vfs_msync(mp, MNT_NOWAIT);
824 		VFS_SYNC(mp, MNT_NOWAIT);
825 		mp->mnt_flag |= asyncflag;
826 	}
827 	return(0);
828 }
829 
830 /* XXX PRISON: could be per prison flag */
831 static int prison_quotas;
832 #if 0
833 SYSCTL_INT(_kern_prison, OID_AUTO, quotas, CTLFLAG_RW, &prison_quotas, 0, "");
834 #endif
835 
836 /*
837  *  quotactl_args(char *path, int fcmd, int uid, caddr_t arg)
838  *
839  * Change filesystem quotas.
840  */
841 /* ARGSUSED */
842 int
843 sys_quotactl(struct quotactl_args *uap)
844 {
845 	struct nlookupdata nd;
846 	struct thread *td;
847 	struct proc *p;
848 	struct mount *mp;
849 	int error;
850 
851 	td = curthread;
852 	p = td->td_proc;
853 	if (p->p_ucred->cr_prison && !prison_quotas)
854 		return (EPERM);
855 
856 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
857 	if (error == 0)
858 		error = nlookup(&nd);
859 	if (error == 0) {
860 		mp = nd.nl_nch.mount;
861 		error = VFS_QUOTACTL(mp, uap->cmd, uap->uid,
862 				    uap->arg, nd.nl_cred);
863 	}
864 	nlookup_done(&nd);
865 	return (error);
866 }
867 
868 /*
869  * mountctl(char *path, int op, int fd, const void *ctl, int ctllen,
870  *		void *buf, int buflen)
871  *
872  * This function operates on a mount point and executes the specified
873  * operation using the specified control data, and possibly returns data.
874  *
875  * The actual number of bytes stored in the result buffer is returned, 0
876  * if none, otherwise an error is returned.
877  */
878 /* ARGSUSED */
879 int
880 sys_mountctl(struct mountctl_args *uap)
881 {
882 	struct thread *td = curthread;
883 	struct proc *p = td->td_proc;
884 	struct file *fp;
885 	void *ctl = NULL;
886 	void *buf = NULL;
887 	char *path = NULL;
888 	int error;
889 
890 	/*
891 	 * Sanity and permissions checks.  We must be root.
892 	 */
893 	KKASSERT(p);
894 	if (p->p_ucred->cr_prison != NULL)
895 		return (EPERM);
896 	if ((error = suser(td)) != 0)
897 		return (error);
898 
899 	/*
900 	 * Argument length checks
901 	 */
902 	if (uap->ctllen < 0 || uap->ctllen > 1024)
903 		return (EINVAL);
904 	if (uap->buflen < 0 || uap->buflen > 16 * 1024)
905 		return (EINVAL);
906 	if (uap->path == NULL)
907 		return (EINVAL);
908 
909 	/*
910 	 * Allocate the necessary buffers and copyin data
911 	 */
912 	path = objcache_get(namei_oc, M_WAITOK);
913 	error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
914 	if (error)
915 		goto done;
916 
917 	if (uap->ctllen) {
918 		ctl = kmalloc(uap->ctllen + 1, M_TEMP, M_WAITOK|M_ZERO);
919 		error = copyin(uap->ctl, ctl, uap->ctllen);
920 		if (error)
921 			goto done;
922 	}
923 	if (uap->buflen)
924 		buf = kmalloc(uap->buflen + 1, M_TEMP, M_WAITOK|M_ZERO);
925 
926 	/*
927 	 * Validate the descriptor
928 	 */
929 	fp = holdfp(p->p_fd, uap->fd, -1);
930 	if (fp == NULL) {
931 		error = EBADF;
932 		goto done;
933 	}
934 
935 	/*
936 	 * Execute the internal kernel function and clean up.
937 	 */
938 	error = kern_mountctl(path, uap->op, fp, ctl, uap->ctllen, buf, uap->buflen, &uap->sysmsg_result);
939 	if (fp)
940 		fdrop(fp);
941 	if (error == 0 && uap->sysmsg_result > 0)
942 		error = copyout(buf, uap->buf, uap->sysmsg_result);
943 done:
944 	if (path)
945 		objcache_put(namei_oc, path);
946 	if (ctl)
947 		kfree(ctl, M_TEMP);
948 	if (buf)
949 		kfree(buf, M_TEMP);
950 	return (error);
951 }
952 
953 /*
954  * Execute a mount control operation by resolving the path to a mount point
955  * and calling vop_mountctl().
956  */
957 int
958 kern_mountctl(const char *path, int op, struct file *fp,
959 		const void *ctl, int ctllen,
960 		void *buf, int buflen, int *res)
961 {
962 	struct vnode *vp;
963 	struct mount *mp;
964 	struct nlookupdata nd;
965 	int error;
966 
967 	*res = 0;
968 	vp = NULL;
969 	error = nlookup_init(&nd, path, UIO_SYSSPACE, NLC_FOLLOW);
970 	if (error == 0)
971 		error = nlookup(&nd);
972 	if (error == 0)
973 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
974 	nlookup_done(&nd);
975 	if (error)
976 		return (error);
977 
978 	mp = vp->v_mount;
979 
980 	/*
981 	 * Must be the root of the filesystem
982 	 */
983 	if ((vp->v_flag & VROOT) == 0) {
984 		vput(vp);
985 		return (EINVAL);
986 	}
987 	error = vop_mountctl(mp->mnt_vn_use_ops, op, fp, ctl, ctllen,
988 				buf, buflen, res);
989 	vput(vp);
990 	return (error);
991 }
992 
993 int
994 kern_statfs(struct nlookupdata *nd, struct statfs *buf)
995 {
996 	struct thread *td = curthread;
997 	struct proc *p = td->td_proc;
998 	struct mount *mp;
999 	struct statfs *sp;
1000 	char *fullpath, *freepath;
1001 	int error;
1002 
1003 	if ((error = nlookup(nd)) != 0)
1004 		return (error);
1005 	mp = nd->nl_nch.mount;
1006 	sp = &mp->mnt_stat;
1007 	if ((error = VFS_STATFS(mp, sp, nd->nl_cred)) != 0)
1008 		return (error);
1009 
1010 	error = mount_path(p, mp, &fullpath, &freepath);
1011 	if (error)
1012 		return(error);
1013 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1014 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1015 	kfree(freepath, M_TEMP);
1016 
1017 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1018 	bcopy(sp, buf, sizeof(*buf));
1019 	/* Only root should have access to the fsid's. */
1020 	if (suser(td))
1021 		buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
1022 	return (0);
1023 }
1024 
1025 /*
1026  * statfs_args(char *path, struct statfs *buf)
1027  *
1028  * Get filesystem statistics.
1029  */
1030 int
1031 sys_statfs(struct statfs_args *uap)
1032 {
1033 	struct nlookupdata nd;
1034 	struct statfs buf;
1035 	int error;
1036 
1037 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1038 	if (error == 0)
1039 		error = kern_statfs(&nd, &buf);
1040 	nlookup_done(&nd);
1041 	if (error == 0)
1042 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1043 	return (error);
1044 }
1045 
1046 int
1047 kern_fstatfs(int fd, struct statfs *buf)
1048 {
1049 	struct thread *td = curthread;
1050 	struct proc *p = td->td_proc;
1051 	struct file *fp;
1052 	struct mount *mp;
1053 	struct statfs *sp;
1054 	char *fullpath, *freepath;
1055 	int error;
1056 
1057 	KKASSERT(p);
1058 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
1059 		return (error);
1060 	mp = ((struct vnode *)fp->f_data)->v_mount;
1061 	if (mp == NULL) {
1062 		error = EBADF;
1063 		goto done;
1064 	}
1065 	if (fp->f_cred == NULL) {
1066 		error = EINVAL;
1067 		goto done;
1068 	}
1069 	sp = &mp->mnt_stat;
1070 	if ((error = VFS_STATFS(mp, sp, fp->f_cred)) != 0)
1071 		goto done;
1072 
1073 	if ((error = mount_path(p, mp, &fullpath, &freepath)) != 0)
1074 		goto done;
1075 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1076 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1077 	kfree(freepath, M_TEMP);
1078 
1079 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1080 	bcopy(sp, buf, sizeof(*buf));
1081 
1082 	/* Only root should have access to the fsid's. */
1083 	if (suser(td))
1084 		buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
1085 	error = 0;
1086 done:
1087 	fdrop(fp);
1088 	return (error);
1089 }
1090 
1091 /*
1092  * fstatfs_args(int fd, struct statfs *buf)
1093  *
1094  * Get filesystem statistics.
1095  */
1096 int
1097 sys_fstatfs(struct fstatfs_args *uap)
1098 {
1099 	struct statfs buf;
1100 	int error;
1101 
1102 	error = kern_fstatfs(uap->fd, &buf);
1103 
1104 	if (error == 0)
1105 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1106 	return (error);
1107 }
1108 
1109 /*
1110  * getfsstat_args(struct statfs *buf, long bufsize, int flags)
1111  *
1112  * Get statistics on all filesystems.
1113  */
1114 
1115 struct getfsstat_info {
1116 	struct statfs *sfsp;
1117 	long count;
1118 	long maxcount;
1119 	int error;
1120 	int flags;
1121 	struct proc *p;
1122 };
1123 
1124 static int getfsstat_callback(struct mount *, void *);
1125 
1126 /* ARGSUSED */
1127 int
1128 sys_getfsstat(struct getfsstat_args *uap)
1129 {
1130 	struct thread *td = curthread;
1131 	struct proc *p = td->td_proc;
1132 	struct getfsstat_info info;
1133 
1134 	bzero(&info, sizeof(info));
1135 
1136 	info.maxcount = uap->bufsize / sizeof(struct statfs);
1137 	info.sfsp = uap->buf;
1138 	info.count = 0;
1139 	info.flags = uap->flags;
1140 	info.p = p;
1141 
1142 	mountlist_scan(getfsstat_callback, &info, MNTSCAN_FORWARD);
1143 	if (info.sfsp && info.count > info.maxcount)
1144 		uap->sysmsg_result = info.maxcount;
1145 	else
1146 		uap->sysmsg_result = info.count;
1147 	return (info.error);
1148 }
1149 
1150 static int
1151 getfsstat_callback(struct mount *mp, void *data)
1152 {
1153 	struct getfsstat_info *info = data;
1154 	struct statfs *sp;
1155 	char *freepath;
1156 	char *fullpath;
1157 	int error;
1158 
1159 	if (info->sfsp && info->count < info->maxcount) {
1160 		if (info->p && !chroot_visible_mnt(mp, info->p))
1161 			return(0);
1162 		sp = &mp->mnt_stat;
1163 
1164 		/*
1165 		 * If MNT_NOWAIT or MNT_LAZY is specified, do not
1166 		 * refresh the fsstat cache. MNT_NOWAIT or MNT_LAZY
1167 		 * overrides MNT_WAIT.
1168 		 */
1169 		if (((info->flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
1170 		    (info->flags & MNT_WAIT)) &&
1171 		    (error = VFS_STATFS(mp, sp, info->p->p_ucred))) {
1172 			return(0);
1173 		}
1174 		sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1175 
1176 		error = mount_path(info->p, mp, &fullpath, &freepath);
1177 		if (error) {
1178 			info->error = error;
1179 			return(-1);
1180 		}
1181 		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1182 		strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1183 		kfree(freepath, M_TEMP);
1184 
1185 		error = copyout(sp, info->sfsp, sizeof(*sp));
1186 		if (error) {
1187 			info->error = error;
1188 			return (-1);
1189 		}
1190 		++info->sfsp;
1191 	}
1192 	info->count++;
1193 	return(0);
1194 }
1195 
1196 /*
1197  * fchdir_args(int fd)
1198  *
1199  * Change current working directory to a given file descriptor.
1200  */
1201 /* ARGSUSED */
1202 int
1203 sys_fchdir(struct fchdir_args *uap)
1204 {
1205 	struct thread *td = curthread;
1206 	struct proc *p = td->td_proc;
1207 	struct filedesc *fdp = p->p_fd;
1208 	struct vnode *vp, *ovp;
1209 	struct mount *mp;
1210 	struct file *fp;
1211 	struct nchandle nch, onch, tnch;
1212 	int error;
1213 
1214 	if ((error = holdvnode(fdp, uap->fd, &fp)) != 0)
1215 		return (error);
1216 	vp = (struct vnode *)fp->f_data;
1217 	vref(vp);
1218 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1219 	if (vp->v_type != VDIR || fp->f_nchandle.ncp == NULL)
1220 		error = ENOTDIR;
1221 	else
1222 		error = VOP_ACCESS(vp, VEXEC, p->p_ucred);
1223 	if (error) {
1224 		vput(vp);
1225 		fdrop(fp);
1226 		return (error);
1227 	}
1228 	cache_copy(&fp->f_nchandle, &nch);
1229 
1230 	/*
1231 	 * If the ncp has become a mount point, traverse through
1232 	 * the mount point.
1233 	 */
1234 
1235 	while (!error && (nch.ncp->nc_flag & NCF_ISMOUNTPT) &&
1236 	       (mp = cache_findmount(&nch)) != NULL
1237 	) {
1238 		error = nlookup_mp(mp, &tnch);
1239 		if (error == 0) {
1240 			cache_unlock(&tnch);	/* leave ref intact */
1241 			vput(vp);
1242 			vp = tnch.ncp->nc_vp;
1243 			error = vget(vp, LK_SHARED);
1244 			KKASSERT(error == 0);
1245 			cache_drop(&nch);
1246 			nch = tnch;
1247 		}
1248 	}
1249 	if (error == 0) {
1250 		ovp = fdp->fd_cdir;
1251 		onch = fdp->fd_ncdir;
1252 		vn_unlock(vp);		/* leave ref intact */
1253 		fdp->fd_cdir = vp;
1254 		fdp->fd_ncdir = nch;
1255 		cache_drop(&onch);
1256 		vrele(ovp);
1257 	} else {
1258 		cache_drop(&nch);
1259 		vput(vp);
1260 	}
1261 	fdrop(fp);
1262 	return (error);
1263 }
1264 
1265 int
1266 kern_chdir(struct nlookupdata *nd)
1267 {
1268 	struct thread *td = curthread;
1269 	struct proc *p = td->td_proc;
1270 	struct filedesc *fdp = p->p_fd;
1271 	struct vnode *vp, *ovp;
1272 	struct nchandle onch;
1273 	int error;
1274 
1275 	if ((error = nlookup(nd)) != 0)
1276 		return (error);
1277 	if ((vp = nd->nl_nch.ncp->nc_vp) == NULL)
1278 		return (ENOENT);
1279 	if ((error = vget(vp, LK_SHARED)) != 0)
1280 		return (error);
1281 
1282 	error = checkvp_chdir(vp, td);
1283 	vn_unlock(vp);
1284 	if (error == 0) {
1285 		ovp = fdp->fd_cdir;
1286 		onch = fdp->fd_ncdir;
1287 		cache_unlock(&nd->nl_nch);	/* leave reference intact */
1288 		fdp->fd_ncdir = nd->nl_nch;
1289 		fdp->fd_cdir = vp;
1290 		cache_drop(&onch);
1291 		vrele(ovp);
1292 		cache_zero(&nd->nl_nch);
1293 	} else {
1294 		vrele(vp);
1295 	}
1296 	return (error);
1297 }
1298 
1299 /*
1300  * chdir_args(char *path)
1301  *
1302  * Change current working directory (``.'').
1303  */
1304 int
1305 sys_chdir(struct chdir_args *uap)
1306 {
1307 	struct nlookupdata nd;
1308 	int error;
1309 
1310 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1311 	if (error == 0)
1312 		error = kern_chdir(&nd);
1313 	nlookup_done(&nd);
1314 	return (error);
1315 }
1316 
1317 /*
1318  * Helper function for raised chroot(2) security function:  Refuse if
1319  * any filedescriptors are open directories.
1320  */
1321 static int
1322 chroot_refuse_vdir_fds(struct filedesc *fdp)
1323 {
1324 	struct vnode *vp;
1325 	struct file *fp;
1326 	int error;
1327 	int fd;
1328 
1329 	for (fd = 0; fd < fdp->fd_nfiles ; fd++) {
1330 		if ((error = holdvnode(fdp, fd, &fp)) != 0)
1331 			continue;
1332 		vp = (struct vnode *)fp->f_data;
1333 		if (vp->v_type != VDIR) {
1334 			fdrop(fp);
1335 			continue;
1336 		}
1337 		fdrop(fp);
1338 		return(EPERM);
1339 	}
1340 	return (0);
1341 }
1342 
1343 /*
1344  * This sysctl determines if we will allow a process to chroot(2) if it
1345  * has a directory open:
1346  *	0: disallowed for all processes.
1347  *	1: allowed for processes that were not already chroot(2)'ed.
1348  *	2: allowed for all processes.
1349  */
1350 
1351 static int chroot_allow_open_directories = 1;
1352 
1353 SYSCTL_INT(_kern, OID_AUTO, chroot_allow_open_directories, CTLFLAG_RW,
1354      &chroot_allow_open_directories, 0, "");
1355 
1356 /*
1357  * chroot to the specified namecache entry.  We obtain the vp from the
1358  * namecache data.  The passed ncp must be locked and referenced and will
1359  * remain locked and referenced on return.
1360  */
1361 int
1362 kern_chroot(struct nchandle *nch)
1363 {
1364 	struct thread *td = curthread;
1365 	struct proc *p = td->td_proc;
1366 	struct filedesc *fdp = p->p_fd;
1367 	struct vnode *vp;
1368 	int error;
1369 
1370 	/*
1371 	 * Only root can chroot
1372 	 */
1373 	if ((error = suser_cred(p->p_ucred, PRISON_ROOT)) != 0)
1374 		return (error);
1375 
1376 	/*
1377 	 * Disallow open directory descriptors (fchdir() breakouts).
1378 	 */
1379 	if (chroot_allow_open_directories == 0 ||
1380 	   (chroot_allow_open_directories == 1 && fdp->fd_rdir != rootvnode)) {
1381 		if ((error = chroot_refuse_vdir_fds(fdp)) != 0)
1382 			return (error);
1383 	}
1384 	if ((vp = nch->ncp->nc_vp) == NULL)
1385 		return (ENOENT);
1386 
1387 	if ((error = vget(vp, LK_SHARED)) != 0)
1388 		return (error);
1389 
1390 	/*
1391 	 * Check the validity of vp as a directory to change to and
1392 	 * associate it with rdir/jdir.
1393 	 */
1394 	error = checkvp_chdir(vp, td);
1395 	vn_unlock(vp);			/* leave reference intact */
1396 	if (error == 0) {
1397 		vrele(fdp->fd_rdir);
1398 		fdp->fd_rdir = vp;	/* reference inherited by fd_rdir */
1399 		cache_drop(&fdp->fd_nrdir);
1400 		cache_copy(nch, &fdp->fd_nrdir);
1401 		if (fdp->fd_jdir == NULL) {
1402 			fdp->fd_jdir = vp;
1403 			vref(fdp->fd_jdir);
1404 			cache_copy(nch, &fdp->fd_njdir);
1405 		}
1406 	} else {
1407 		vrele(vp);
1408 	}
1409 	return (error);
1410 }
1411 
1412 /*
1413  * chroot_args(char *path)
1414  *
1415  * Change notion of root (``/'') directory.
1416  */
1417 /* ARGSUSED */
1418 int
1419 sys_chroot(struct chroot_args *uap)
1420 {
1421 	struct thread *td = curthread;
1422 	struct nlookupdata nd;
1423 	int error;
1424 
1425 	KKASSERT(td->td_proc);
1426 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1427 	if (error) {
1428 		nlookup_done(&nd);
1429 		return(error);
1430 	}
1431 	error = nlookup(&nd);
1432 	if (error == 0)
1433 		error = kern_chroot(&nd.nl_nch);
1434 	nlookup_done(&nd);
1435 	return(error);
1436 }
1437 
1438 /*
1439  * Common routine for chroot and chdir.  Given a locked, referenced vnode,
1440  * determine whether it is legal to chdir to the vnode.  The vnode's state
1441  * is not changed by this call.
1442  */
1443 int
1444 checkvp_chdir(struct vnode *vp, struct thread *td)
1445 {
1446 	int error;
1447 
1448 	if (vp->v_type != VDIR)
1449 		error = ENOTDIR;
1450 	else
1451 		error = VOP_ACCESS(vp, VEXEC, td->td_proc->p_ucred);
1452 	return (error);
1453 }
1454 
1455 int
1456 kern_open(struct nlookupdata *nd, int oflags, int mode, int *res)
1457 {
1458 	struct thread *td = curthread;
1459 	struct proc *p = td->td_proc;
1460 	struct lwp *lp = td->td_lwp;
1461 	struct filedesc *fdp = p->p_fd;
1462 	int cmode, flags;
1463 	struct file *nfp;
1464 	struct file *fp;
1465 	struct vnode *vp;
1466 	int type, indx, error;
1467 	struct flock lf;
1468 
1469 	if ((oflags & O_ACCMODE) == O_ACCMODE)
1470 		return (EINVAL);
1471 	flags = FFLAGS(oflags);
1472 	error = falloc(p, &nfp, NULL);
1473 	if (error)
1474 		return (error);
1475 	fp = nfp;
1476 	cmode = ((mode &~ fdp->fd_cmask) & ALLPERMS) &~ S_ISTXT;
1477 
1478 	/*
1479 	 * XXX p_dupfd is a real mess.  It allows a device to return a
1480 	 * file descriptor to be duplicated rather then doing the open
1481 	 * itself.
1482 	 */
1483 	lp->lwp_dupfd = -1;
1484 
1485 	/*
1486 	 * Call vn_open() to do the lookup and assign the vnode to the
1487 	 * file pointer.  vn_open() does not change the ref count on fp
1488 	 * and the vnode, on success, will be inherited by the file pointer
1489 	 * and unlocked.
1490 	 */
1491 	nd->nl_flags |= NLC_LOCKVP;
1492 	error = vn_open(nd, fp, flags, cmode);
1493 	nlookup_done(nd);
1494 	if (error) {
1495 		/*
1496 		 * handle special fdopen() case.  bleh.  dupfdopen() is
1497 		 * responsible for dropping the old contents of ofiles[indx]
1498 		 * if it succeeds.
1499 		 *
1500 		 * Note that fsetfd() will add a ref to fp which represents
1501 		 * the fd_files[] assignment.  We must still drop our
1502 		 * reference.
1503 		 */
1504 		if ((error == ENODEV || error == ENXIO) && lp->lwp_dupfd >= 0) {
1505 			if (fdalloc(p, 0, &indx) == 0) {
1506 				error = dupfdopen(p, indx, lp->lwp_dupfd, flags, error);
1507 				if (error == 0) {
1508 					*res = indx;
1509 					fdrop(fp);	/* our ref */
1510 					return (0);
1511 				}
1512 				fsetfd(p, NULL, indx);
1513 			}
1514 		}
1515 		fdrop(fp);	/* our ref */
1516 		if (error == ERESTART)
1517 			error = EINTR;
1518 		return (error);
1519 	}
1520 
1521 	/*
1522 	 * ref the vnode for ourselves so it can't be ripped out from under
1523 	 * is.  XXX need an ND flag to request that the vnode be returned
1524 	 * anyway.
1525 	 *
1526 	 * Reserve a file descriptor but do not assign it until the open
1527 	 * succeeds.
1528 	 */
1529 	vp = (struct vnode *)fp->f_data;
1530 	vref(vp);
1531 	if ((error = fdalloc(p, 0, &indx)) != 0) {
1532 		fdrop(fp);
1533 		vrele(vp);
1534 		return (error);
1535 	}
1536 
1537 	/*
1538 	 * If no error occurs the vp will have been assigned to the file
1539 	 * pointer.
1540 	 */
1541 	lp->lwp_dupfd = 0;
1542 
1543 	if (flags & (O_EXLOCK | O_SHLOCK)) {
1544 		lf.l_whence = SEEK_SET;
1545 		lf.l_start = 0;
1546 		lf.l_len = 0;
1547 		if (flags & O_EXLOCK)
1548 			lf.l_type = F_WRLCK;
1549 		else
1550 			lf.l_type = F_RDLCK;
1551 		if (flags & FNONBLOCK)
1552 			type = 0;
1553 		else
1554 			type = F_WAIT;
1555 
1556 		if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0) {
1557 			/*
1558 			 * lock request failed.  Clean up the reserved
1559 			 * descriptor.
1560 			 */
1561 			vrele(vp);
1562 			fsetfd(p, NULL, indx);
1563 			fdrop(fp);
1564 			return (error);
1565 		}
1566 		fp->f_flag |= FHASLOCK;
1567 	}
1568 #if 0
1569 	/*
1570 	 * Assert that all regular file vnodes were created with a object.
1571 	 */
1572 	KASSERT(vp->v_type != VREG || vp->v_object != NULL,
1573 		("open: regular file has no backing object after vn_open"));
1574 #endif
1575 
1576 	vrele(vp);
1577 
1578 	/*
1579 	 * release our private reference, leaving the one associated with the
1580 	 * descriptor table intact.
1581 	 */
1582 	fsetfd(p, fp, indx);
1583 	fdrop(fp);
1584 	*res = indx;
1585 	return (0);
1586 }
1587 
1588 /*
1589  * open_args(char *path, int flags, int mode)
1590  *
1591  * Check permissions, allocate an open file structure,
1592  * and call the device open routine if any.
1593  */
1594 int
1595 sys_open(struct open_args *uap)
1596 {
1597 	struct nlookupdata nd;
1598 	int error;
1599 
1600 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1601 	if (error == 0) {
1602 		error = kern_open(&nd, uap->flags,
1603 				    uap->mode, &uap->sysmsg_result);
1604 	}
1605 	nlookup_done(&nd);
1606 	return (error);
1607 }
1608 
1609 int
1610 kern_mknod(struct nlookupdata *nd, int mode, int dev)
1611 {
1612 	struct thread *td = curthread;
1613 	struct proc *p = td->td_proc;
1614 	struct vnode *vp;
1615 	struct vattr vattr;
1616 	int error;
1617 	int whiteout = 0;
1618 
1619 	KKASSERT(p);
1620 
1621 	switch (mode & S_IFMT) {
1622 	case S_IFCHR:
1623 	case S_IFBLK:
1624 		error = suser(td);
1625 		break;
1626 	default:
1627 		error = suser_cred(p->p_ucred, PRISON_ROOT);
1628 		break;
1629 	}
1630 	if (error)
1631 		return (error);
1632 
1633 	bwillwrite();
1634 	nd->nl_flags |= NLC_CREATE;
1635 	if ((error = nlookup(nd)) != 0)
1636 		return (error);
1637 	if (nd->nl_nch.ncp->nc_vp)
1638 		return (EEXIST);
1639 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
1640 		return (error);
1641 
1642 	VATTR_NULL(&vattr);
1643 	vattr.va_mode = (mode & ALLPERMS) &~ p->p_fd->fd_cmask;
1644 	vattr.va_rdev = dev;
1645 	whiteout = 0;
1646 
1647 	switch (mode & S_IFMT) {
1648 	case S_IFMT:	/* used by badsect to flag bad sectors */
1649 		vattr.va_type = VBAD;
1650 		break;
1651 	case S_IFCHR:
1652 		vattr.va_type = VCHR;
1653 		break;
1654 	case S_IFBLK:
1655 		vattr.va_type = VBLK;
1656 		break;
1657 	case S_IFWHT:
1658 		whiteout = 1;
1659 		break;
1660 	default:
1661 		error = EINVAL;
1662 		break;
1663 	}
1664 	if (error == 0) {
1665 		if (whiteout) {
1666 			error = VOP_NWHITEOUT(&nd->nl_nch, nd->nl_cred, NAMEI_CREATE);
1667 		} else {
1668 			vp = NULL;
1669 			error = VOP_NMKNOD(&nd->nl_nch, &vp, nd->nl_cred, &vattr);
1670 			if (error == 0)
1671 				vput(vp);
1672 		}
1673 	}
1674 	return (error);
1675 }
1676 
1677 /*
1678  * mknod_args(char *path, int mode, int dev)
1679  *
1680  * Create a special file.
1681  */
1682 int
1683 sys_mknod(struct mknod_args *uap)
1684 {
1685 	struct nlookupdata nd;
1686 	int error;
1687 
1688 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
1689 	if (error == 0)
1690 		error = kern_mknod(&nd, uap->mode, uap->dev);
1691 	nlookup_done(&nd);
1692 	return (error);
1693 }
1694 
1695 int
1696 kern_mkfifo(struct nlookupdata *nd, int mode)
1697 {
1698 	struct thread *td = curthread;
1699 	struct proc *p = td->td_proc;
1700 	struct vattr vattr;
1701 	struct vnode *vp;
1702 	int error;
1703 
1704 	bwillwrite();
1705 
1706 	nd->nl_flags |= NLC_CREATE;
1707 	if ((error = nlookup(nd)) != 0)
1708 		return (error);
1709 	if (nd->nl_nch.ncp->nc_vp)
1710 		return (EEXIST);
1711 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
1712 		return (error);
1713 
1714 	VATTR_NULL(&vattr);
1715 	vattr.va_type = VFIFO;
1716 	vattr.va_mode = (mode & ALLPERMS) &~ p->p_fd->fd_cmask;
1717 	vp = NULL;
1718 	error = VOP_NMKNOD(&nd->nl_nch, &vp, nd->nl_cred, &vattr);
1719 	if (error == 0)
1720 		vput(vp);
1721 	return (error);
1722 }
1723 
1724 /*
1725  * mkfifo_args(char *path, int mode)
1726  *
1727  * Create a named pipe.
1728  */
1729 int
1730 sys_mkfifo(struct mkfifo_args *uap)
1731 {
1732 	struct nlookupdata nd;
1733 	int error;
1734 
1735 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
1736 	if (error == 0)
1737 		error = kern_mkfifo(&nd, uap->mode);
1738 	nlookup_done(&nd);
1739 	return (error);
1740 }
1741 
1742 static int hardlink_check_uid = 0;
1743 SYSCTL_INT(_kern, OID_AUTO, hardlink_check_uid, CTLFLAG_RW,
1744     &hardlink_check_uid, 0,
1745     "Unprivileged processes cannot create hard links to files owned by other "
1746     "users");
1747 static int hardlink_check_gid = 0;
1748 SYSCTL_INT(_kern, OID_AUTO, hardlink_check_gid, CTLFLAG_RW,
1749     &hardlink_check_gid, 0,
1750     "Unprivileged processes cannot create hard links to files owned by other "
1751     "groups");
1752 
1753 static int
1754 can_hardlink(struct vnode *vp, struct thread *td, struct ucred *cred)
1755 {
1756 	struct vattr va;
1757 	int error;
1758 
1759 	/*
1760 	 * Shortcut if disabled
1761 	 */
1762 	if (hardlink_check_uid == 0 && hardlink_check_gid == 0)
1763 		return (0);
1764 
1765 	/*
1766 	 * root cred can always hardlink
1767 	 */
1768 	if (suser_cred(cred, PRISON_ROOT) == 0)
1769 		return (0);
1770 
1771 	/*
1772 	 * Otherwise only if the originating file is owned by the
1773 	 * same user or group.  Note that any group is allowed if
1774 	 * the file is owned by the caller.
1775 	 */
1776 	error = VOP_GETATTR(vp, &va);
1777 	if (error != 0)
1778 		return (error);
1779 
1780 	if (hardlink_check_uid) {
1781 		if (cred->cr_uid != va.va_uid)
1782 			return (EPERM);
1783 	}
1784 
1785 	if (hardlink_check_gid) {
1786 		if (cred->cr_uid != va.va_uid && !groupmember(va.va_gid, cred))
1787 			return (EPERM);
1788 	}
1789 
1790 	return (0);
1791 }
1792 
1793 int
1794 kern_link(struct nlookupdata *nd, struct nlookupdata *linknd)
1795 {
1796 	struct thread *td = curthread;
1797 	struct vnode *vp;
1798 	int error;
1799 
1800 	/*
1801 	 * Lookup the source and obtained a locked vnode.
1802 	 *
1803 	 * XXX relookup on vget failure / race ?
1804 	 */
1805 	bwillwrite();
1806 	if ((error = nlookup(nd)) != 0)
1807 		return (error);
1808 	vp = nd->nl_nch.ncp->nc_vp;
1809 	KKASSERT(vp != NULL);
1810 	if (vp->v_type == VDIR)
1811 		return (EPERM);		/* POSIX */
1812 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
1813 		return (error);
1814 	if ((error = vget(vp, LK_EXCLUSIVE)) != 0)
1815 		return (error);
1816 
1817 	/*
1818 	 * Unlock the source so we can lookup the target without deadlocking
1819 	 * (XXX vp is locked already, possible other deadlock?).  The target
1820 	 * must not exist.
1821 	 */
1822 	KKASSERT(nd->nl_flags & NLC_NCPISLOCKED);
1823 	nd->nl_flags &= ~NLC_NCPISLOCKED;
1824 	cache_unlock(&nd->nl_nch);
1825 
1826 	linknd->nl_flags |= NLC_CREATE;
1827 	if ((error = nlookup(linknd)) != 0) {
1828 		vput(vp);
1829 		return (error);
1830 	}
1831 	if (linknd->nl_nch.ncp->nc_vp) {
1832 		vput(vp);
1833 		return (EEXIST);
1834 	}
1835 
1836 	/*
1837 	 * Finally run the new API VOP.
1838 	 */
1839 	error = can_hardlink(vp, td, td->td_proc->p_ucred);
1840 	if (error == 0)
1841 		error = VOP_NLINK(&linknd->nl_nch, vp, linknd->nl_cred);
1842 	vput(vp);
1843 	return (error);
1844 }
1845 
1846 /*
1847  * link_args(char *path, char *link)
1848  *
1849  * Make a hard file link.
1850  */
1851 int
1852 sys_link(struct link_args *uap)
1853 {
1854 	struct nlookupdata nd, linknd;
1855 	int error;
1856 
1857 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1858 	if (error == 0) {
1859 		error = nlookup_init(&linknd, uap->link, UIO_USERSPACE, 0);
1860 		if (error == 0)
1861 			error = kern_link(&nd, &linknd);
1862 		nlookup_done(&linknd);
1863 	}
1864 	nlookup_done(&nd);
1865 	return (error);
1866 }
1867 
1868 int
1869 kern_symlink(struct nlookupdata *nd, char *path, int mode)
1870 {
1871 	struct vattr vattr;
1872 	struct vnode *vp;
1873 	int error;
1874 
1875 	bwillwrite();
1876 	nd->nl_flags |= NLC_CREATE;
1877 	if ((error = nlookup(nd)) != 0)
1878 		return (error);
1879 	if (nd->nl_nch.ncp->nc_vp)
1880 		return (EEXIST);
1881 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
1882 		return (error);
1883 	VATTR_NULL(&vattr);
1884 	vattr.va_mode = mode;
1885 	error = VOP_NSYMLINK(&nd->nl_nch, &vp, nd->nl_cred, &vattr, path);
1886 	if (error == 0)
1887 		vput(vp);
1888 	return (error);
1889 }
1890 
1891 /*
1892  * symlink(char *path, char *link)
1893  *
1894  * Make a symbolic link.
1895  */
1896 int
1897 sys_symlink(struct symlink_args *uap)
1898 {
1899 	struct thread *td = curthread;
1900 	struct nlookupdata nd;
1901 	char *path;
1902 	int error;
1903 	int mode;
1904 
1905 	path = objcache_get(namei_oc, M_WAITOK);
1906 	error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
1907 	if (error == 0) {
1908 		error = nlookup_init(&nd, uap->link, UIO_USERSPACE, 0);
1909 		if (error == 0) {
1910 			mode = ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask;
1911 			error = kern_symlink(&nd, path, mode);
1912 		}
1913 		nlookup_done(&nd);
1914 	}
1915 	objcache_put(namei_oc, path);
1916 	return (error);
1917 }
1918 
1919 /*
1920  * undelete_args(char *path)
1921  *
1922  * Delete a whiteout from the filesystem.
1923  */
1924 /* ARGSUSED */
1925 int
1926 sys_undelete(struct undelete_args *uap)
1927 {
1928 	struct nlookupdata nd;
1929 	int error;
1930 
1931 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
1932 	bwillwrite();
1933 	nd.nl_flags |= NLC_DELETE;
1934 	if (error == 0)
1935 		error = nlookup(&nd);
1936 	if (error == 0)
1937 		error = ncp_writechk(&nd.nl_nch);
1938 	if (error == 0)
1939 		error = VOP_NWHITEOUT(&nd.nl_nch, nd.nl_cred, NAMEI_DELETE);
1940 	nlookup_done(&nd);
1941 	return (error);
1942 }
1943 
1944 int
1945 kern_unlink(struct nlookupdata *nd)
1946 {
1947 	int error;
1948 
1949 	bwillwrite();
1950 	nd->nl_flags |= NLC_DELETE;
1951 	if ((error = nlookup(nd)) != 0)
1952 		return (error);
1953 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
1954 		return (error);
1955 	error = VOP_NREMOVE(&nd->nl_nch, nd->nl_cred);
1956 	return (error);
1957 }
1958 
1959 /*
1960  * unlink_args(char *path)
1961  *
1962  * Delete a name from the filesystem.
1963  */
1964 int
1965 sys_unlink(struct unlink_args *uap)
1966 {
1967 	struct nlookupdata nd;
1968 	int error;
1969 
1970 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
1971 	if (error == 0)
1972 		error = kern_unlink(&nd);
1973 	nlookup_done(&nd);
1974 	return (error);
1975 }
1976 
1977 int
1978 kern_lseek(int fd, off_t offset, int whence, off_t *res)
1979 {
1980 	struct thread *td = curthread;
1981 	struct proc *p = td->td_proc;
1982 	struct file *fp;
1983 	struct vattr vattr;
1984 	int error;
1985 
1986 	fp = holdfp(p->p_fd, fd, -1);
1987 	if (fp == NULL)
1988 		return (EBADF);
1989 	if (fp->f_type != DTYPE_VNODE) {
1990 		error = ESPIPE;
1991 		goto done;
1992 	}
1993 
1994 	switch (whence) {
1995 	case L_INCR:
1996 		fp->f_offset += offset;
1997 		error = 0;
1998 		break;
1999 	case L_XTND:
2000 		error = VOP_GETATTR((struct vnode *)fp->f_data, &vattr);
2001 		if (error == 0)
2002 			fp->f_offset = offset + vattr.va_size;
2003 		break;
2004 	case L_SET:
2005 		fp->f_offset = offset;
2006 		error = 0;
2007 		break;
2008 	default:
2009 		error = EINVAL;
2010 		break;
2011 	}
2012 	*res = fp->f_offset;
2013 done:
2014 	fdrop(fp);
2015 	return (error);
2016 }
2017 
2018 /*
2019  * lseek_args(int fd, int pad, off_t offset, int whence)
2020  *
2021  * Reposition read/write file offset.
2022  */
2023 int
2024 sys_lseek(struct lseek_args *uap)
2025 {
2026 	int error;
2027 
2028 	error = kern_lseek(uap->fd, uap->offset, uap->whence,
2029 	    &uap->sysmsg_offset);
2030 
2031 	return (error);
2032 }
2033 
2034 int
2035 kern_access(struct nlookupdata *nd, int aflags)
2036 {
2037 	struct vnode *vp;
2038 	int error, flags;
2039 
2040 	if ((error = nlookup(nd)) != 0)
2041 		return (error);
2042 retry:
2043 	error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_EXCLUSIVE, &vp);
2044 	if (error)
2045 		return (error);
2046 
2047 	/* Flags == 0 means only check for existence. */
2048 	if (aflags) {
2049 		flags = 0;
2050 		if (aflags & R_OK)
2051 			flags |= VREAD;
2052 		if (aflags & W_OK)
2053 			flags |= VWRITE;
2054 		if (aflags & X_OK)
2055 			flags |= VEXEC;
2056 		if ((flags & VWRITE) == 0 ||
2057 		    (error = vn_writechk(vp, &nd->nl_nch)) == 0)
2058 			error = VOP_ACCESS(vp, flags, nd->nl_cred);
2059 
2060 		/*
2061 		 * If the file handle is stale we have to re-resolve the
2062 		 * entry.  This is a hack at the moment.
2063 		 */
2064 		if (error == ESTALE) {
2065 			cache_setunresolved(&nd->nl_nch);
2066 			error = cache_resolve(&nd->nl_nch, nd->nl_cred);
2067 			if (error == 0) {
2068 				vput(vp);
2069 				vp = NULL;
2070 				goto retry;
2071 			}
2072 		}
2073 	}
2074 	vput(vp);
2075 	return (error);
2076 }
2077 
2078 /*
2079  * access_args(char *path, int flags)
2080  *
2081  * Check access permissions.
2082  */
2083 int
2084 sys_access(struct access_args *uap)
2085 {
2086 	struct nlookupdata nd;
2087 	int error;
2088 
2089 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2090 	if (error == 0)
2091 		error = kern_access(&nd, uap->flags);
2092 	nlookup_done(&nd);
2093 	return (error);
2094 }
2095 
2096 int
2097 kern_stat(struct nlookupdata *nd, struct stat *st)
2098 {
2099 	int error;
2100 	struct vnode *vp;
2101 	thread_t td;
2102 
2103 	if ((error = nlookup(nd)) != 0)
2104 		return (error);
2105 again:
2106 	if ((vp = nd->nl_nch.ncp->nc_vp) == NULL)
2107 		return (ENOENT);
2108 
2109 	td = curthread;
2110 	if ((error = vget(vp, LK_SHARED)) != 0)
2111 		return (error);
2112 	error = vn_stat(vp, st, nd->nl_cred);
2113 
2114 	/*
2115 	 * If the file handle is stale we have to re-resolve the entry.  This
2116 	 * is a hack at the moment.
2117 	 */
2118 	if (error == ESTALE) {
2119 		cache_setunresolved(&nd->nl_nch);
2120 		error = cache_resolve(&nd->nl_nch, nd->nl_cred);
2121 		if (error == 0) {
2122 			vput(vp);
2123 			goto again;
2124 		}
2125 	}
2126 	vput(vp);
2127 	return (error);
2128 }
2129 
2130 /*
2131  * stat_args(char *path, struct stat *ub)
2132  *
2133  * Get file status; this version follows links.
2134  */
2135 int
2136 sys_stat(struct stat_args *uap)
2137 {
2138 	struct nlookupdata nd;
2139 	struct stat st;
2140 	int error;
2141 
2142 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2143 	if (error == 0) {
2144 		error = kern_stat(&nd, &st);
2145 		if (error == 0)
2146 			error = copyout(&st, uap->ub, sizeof(*uap->ub));
2147 	}
2148 	nlookup_done(&nd);
2149 	return (error);
2150 }
2151 
2152 /*
2153  * lstat_args(char *path, struct stat *ub)
2154  *
2155  * Get file status; this version does not follow links.
2156  */
2157 int
2158 sys_lstat(struct lstat_args *uap)
2159 {
2160 	struct nlookupdata nd;
2161 	struct stat st;
2162 	int error;
2163 
2164 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2165 	if (error == 0) {
2166 		error = kern_stat(&nd, &st);
2167 		if (error == 0)
2168 			error = copyout(&st, uap->ub, sizeof(*uap->ub));
2169 	}
2170 	nlookup_done(&nd);
2171 	return (error);
2172 }
2173 
2174 /*
2175  * pathconf_Args(char *path, int name)
2176  *
2177  * Get configurable pathname variables.
2178  */
2179 /* ARGSUSED */
2180 int
2181 sys_pathconf(struct pathconf_args *uap)
2182 {
2183 	struct nlookupdata nd;
2184 	struct vnode *vp;
2185 	int error;
2186 
2187 	vp = NULL;
2188 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2189 	if (error == 0)
2190 		error = nlookup(&nd);
2191 	if (error == 0)
2192 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
2193 	nlookup_done(&nd);
2194 	if (error == 0) {
2195 		error = VOP_PATHCONF(vp, uap->name, uap->sysmsg_fds);
2196 		vput(vp);
2197 	}
2198 	return (error);
2199 }
2200 
2201 /*
2202  * XXX: daver
2203  * kern_readlink isn't properly split yet.  There is a copyin burried
2204  * in VOP_READLINK().
2205  */
2206 int
2207 kern_readlink(struct nlookupdata *nd, char *buf, int count, int *res)
2208 {
2209 	struct thread *td = curthread;
2210 	struct proc *p = td->td_proc;
2211 	struct vnode *vp;
2212 	struct iovec aiov;
2213 	struct uio auio;
2214 	int error;
2215 
2216 	if ((error = nlookup(nd)) != 0)
2217 		return (error);
2218 	error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_EXCLUSIVE, &vp);
2219 	if (error)
2220 		return (error);
2221 	if (vp->v_type != VLNK) {
2222 		error = EINVAL;
2223 	} else {
2224 		aiov.iov_base = buf;
2225 		aiov.iov_len = count;
2226 		auio.uio_iov = &aiov;
2227 		auio.uio_iovcnt = 1;
2228 		auio.uio_offset = 0;
2229 		auio.uio_rw = UIO_READ;
2230 		auio.uio_segflg = UIO_USERSPACE;
2231 		auio.uio_td = td;
2232 		auio.uio_resid = count;
2233 		error = VOP_READLINK(vp, &auio, p->p_ucred);
2234 	}
2235 	vput(vp);
2236 	*res = count - auio.uio_resid;
2237 	return (error);
2238 }
2239 
2240 /*
2241  * readlink_args(char *path, char *buf, int count)
2242  *
2243  * Return target name of a symbolic link.
2244  */
2245 int
2246 sys_readlink(struct readlink_args *uap)
2247 {
2248 	struct nlookupdata nd;
2249 	int error;
2250 
2251 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2252 	if (error == 0) {
2253 		error = kern_readlink(&nd, uap->buf, uap->count,
2254 					&uap->sysmsg_result);
2255 	}
2256 	nlookup_done(&nd);
2257 	return (error);
2258 }
2259 
2260 static int
2261 setfflags(struct vnode *vp, int flags)
2262 {
2263 	struct thread *td = curthread;
2264 	struct proc *p = td->td_proc;
2265 	int error;
2266 	struct vattr vattr;
2267 
2268 	/*
2269 	 * Prevent non-root users from setting flags on devices.  When
2270 	 * a device is reused, users can retain ownership of the device
2271 	 * if they are allowed to set flags and programs assume that
2272 	 * chown can't fail when done as root.
2273 	 */
2274 	if ((vp->v_type == VCHR || vp->v_type == VBLK) &&
2275 	    ((error = suser_cred(p->p_ucred, PRISON_ROOT)) != 0))
2276 		return (error);
2277 
2278 	/*
2279 	 * note: vget is required for any operation that might mod the vnode
2280 	 * so VINACTIVE is properly cleared.
2281 	 */
2282 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
2283 		VATTR_NULL(&vattr);
2284 		vattr.va_flags = flags;
2285 		error = VOP_SETATTR(vp, &vattr, p->p_ucred);
2286 		vput(vp);
2287 	}
2288 	return (error);
2289 }
2290 
2291 /*
2292  * chflags(char *path, int flags)
2293  *
2294  * Change flags of a file given a path name.
2295  */
2296 /* ARGSUSED */
2297 int
2298 sys_chflags(struct chflags_args *uap)
2299 {
2300 	struct nlookupdata nd;
2301 	struct vnode *vp;
2302 	int error;
2303 
2304 	vp = NULL;
2305 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2306 	/* XXX Add NLC flag indicating modifying operation? */
2307 	if (error == 0)
2308 		error = nlookup(&nd);
2309 	if (error == 0)
2310 		error = ncp_writechk(&nd.nl_nch);
2311 	if (error == 0)
2312 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
2313 	nlookup_done(&nd);
2314 	if (error == 0) {
2315 		error = setfflags(vp, uap->flags);
2316 		vrele(vp);
2317 	}
2318 	return (error);
2319 }
2320 
2321 /*
2322  * fchflags_args(int fd, int flags)
2323  *
2324  * Change flags of a file given a file descriptor.
2325  */
2326 /* ARGSUSED */
2327 int
2328 sys_fchflags(struct fchflags_args *uap)
2329 {
2330 	struct thread *td = curthread;
2331 	struct proc *p = td->td_proc;
2332 	struct file *fp;
2333 	int error;
2334 
2335 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
2336 		return (error);
2337 	if (fp->f_nchandle.ncp)
2338 		error = ncp_writechk(&fp->f_nchandle);
2339 	if (error == 0)
2340 		error = setfflags((struct vnode *) fp->f_data, uap->flags);
2341 	fdrop(fp);
2342 	return (error);
2343 }
2344 
2345 static int
2346 setfmode(struct vnode *vp, int mode)
2347 {
2348 	struct thread *td = curthread;
2349 	struct proc *p = td->td_proc;
2350 	int error;
2351 	struct vattr vattr;
2352 
2353 	/*
2354 	 * note: vget is required for any operation that might mod the vnode
2355 	 * so VINACTIVE is properly cleared.
2356 	 */
2357 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
2358 		VATTR_NULL(&vattr);
2359 		vattr.va_mode = mode & ALLPERMS;
2360 		error = VOP_SETATTR(vp, &vattr, p->p_ucred);
2361 		vput(vp);
2362 	}
2363 	return error;
2364 }
2365 
2366 int
2367 kern_chmod(struct nlookupdata *nd, int mode)
2368 {
2369 	struct vnode *vp;
2370 	int error;
2371 
2372 	/* XXX Add NLC flag indicating modifying operation? */
2373 	if ((error = nlookup(nd)) != 0)
2374 		return (error);
2375 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
2376 		return (error);
2377 	if ((error = ncp_writechk(&nd->nl_nch)) == 0)
2378 		error = setfmode(vp, mode);
2379 	vrele(vp);
2380 	return (error);
2381 }
2382 
2383 /*
2384  * chmod_args(char *path, int mode)
2385  *
2386  * Change mode of a file given path name.
2387  */
2388 /* ARGSUSED */
2389 int
2390 sys_chmod(struct chmod_args *uap)
2391 {
2392 	struct nlookupdata nd;
2393 	int error;
2394 
2395 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2396 	if (error == 0)
2397 		error = kern_chmod(&nd, uap->mode);
2398 	nlookup_done(&nd);
2399 	return (error);
2400 }
2401 
2402 /*
2403  * lchmod_args(char *path, int mode)
2404  *
2405  * Change mode of a file given path name (don't follow links.)
2406  */
2407 /* ARGSUSED */
2408 int
2409 sys_lchmod(struct lchmod_args *uap)
2410 {
2411 	struct nlookupdata nd;
2412 	int error;
2413 
2414 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2415 	if (error == 0)
2416 		error = kern_chmod(&nd, uap->mode);
2417 	nlookup_done(&nd);
2418 	return (error);
2419 }
2420 
2421 /*
2422  * fchmod_args(int fd, int mode)
2423  *
2424  * Change mode of a file given a file descriptor.
2425  */
2426 /* ARGSUSED */
2427 int
2428 sys_fchmod(struct fchmod_args *uap)
2429 {
2430 	struct thread *td = curthread;
2431 	struct proc *p = td->td_proc;
2432 	struct file *fp;
2433 	int error;
2434 
2435 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
2436 		return (error);
2437 	if (fp->f_nchandle.ncp)
2438 		error = ncp_writechk(&fp->f_nchandle);
2439 	if (error == 0)
2440 		error = setfmode((struct vnode *)fp->f_data, uap->mode);
2441 	fdrop(fp);
2442 	return (error);
2443 }
2444 
2445 static int
2446 setfown(struct vnode *vp, uid_t uid, gid_t gid)
2447 {
2448 	struct thread *td = curthread;
2449 	struct proc *p = td->td_proc;
2450 	int error;
2451 	struct vattr vattr;
2452 
2453 	/*
2454 	 * note: vget is required for any operation that might mod the vnode
2455 	 * so VINACTIVE is properly cleared.
2456 	 */
2457 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
2458 		VATTR_NULL(&vattr);
2459 		vattr.va_uid = uid;
2460 		vattr.va_gid = gid;
2461 		error = VOP_SETATTR(vp, &vattr, p->p_ucred);
2462 		vput(vp);
2463 	}
2464 	return error;
2465 }
2466 
2467 int
2468 kern_chown(struct nlookupdata *nd, int uid, int gid)
2469 {
2470 	struct vnode *vp;
2471 	int error;
2472 
2473 	/* XXX Add NLC flag indicating modifying operation? */
2474 	if ((error = nlookup(nd)) != 0)
2475 		return (error);
2476 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
2477 		return (error);
2478 	if ((error = ncp_writechk(&nd->nl_nch)) == 0)
2479 		error = setfown(vp, uid, gid);
2480 	vrele(vp);
2481 	return (error);
2482 }
2483 
2484 /*
2485  * chown(char *path, int uid, int gid)
2486  *
2487  * Set ownership given a path name.
2488  */
2489 int
2490 sys_chown(struct chown_args *uap)
2491 {
2492 	struct nlookupdata nd;
2493 	int error;
2494 
2495 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2496 	if (error == 0)
2497 		error = kern_chown(&nd, uap->uid, uap->gid);
2498 	nlookup_done(&nd);
2499 	return (error);
2500 }
2501 
2502 /*
2503  * lchown_args(char *path, int uid, int gid)
2504  *
2505  * Set ownership given a path name, do not cross symlinks.
2506  */
2507 int
2508 sys_lchown(struct lchown_args *uap)
2509 {
2510 	struct nlookupdata nd;
2511 	int error;
2512 
2513 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2514 	if (error == 0)
2515 		error = kern_chown(&nd, uap->uid, uap->gid);
2516 	nlookup_done(&nd);
2517 	return (error);
2518 }
2519 
2520 /*
2521  * fchown_args(int fd, int uid, int gid)
2522  *
2523  * Set ownership given a file descriptor.
2524  */
2525 /* ARGSUSED */
2526 int
2527 sys_fchown(struct fchown_args *uap)
2528 {
2529 	struct thread *td = curthread;
2530 	struct proc *p = td->td_proc;
2531 	struct file *fp;
2532 	int error;
2533 
2534 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
2535 		return (error);
2536 	if (fp->f_nchandle.ncp)
2537 		error = ncp_writechk(&fp->f_nchandle);
2538 	if (error == 0)
2539 		error = setfown((struct vnode *)fp->f_data, uap->uid, uap->gid);
2540 	fdrop(fp);
2541 	return (error);
2542 }
2543 
2544 static int
2545 getutimes(const struct timeval *tvp, struct timespec *tsp)
2546 {
2547 	struct timeval tv[2];
2548 
2549 	if (tvp == NULL) {
2550 		microtime(&tv[0]);
2551 		TIMEVAL_TO_TIMESPEC(&tv[0], &tsp[0]);
2552 		tsp[1] = tsp[0];
2553 	} else {
2554 		TIMEVAL_TO_TIMESPEC(&tvp[0], &tsp[0]);
2555 		TIMEVAL_TO_TIMESPEC(&tvp[1], &tsp[1]);
2556 	}
2557 	return 0;
2558 }
2559 
2560 static int
2561 setutimes(struct vnode *vp, const struct timespec *ts, int nullflag)
2562 {
2563 	struct thread *td = curthread;
2564 	struct proc *p = td->td_proc;
2565 	int error;
2566 	struct vattr vattr;
2567 
2568 	/*
2569 	 * note: vget is required for any operation that might mod the vnode
2570 	 * so VINACTIVE is properly cleared.
2571 	 */
2572 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
2573 		VATTR_NULL(&vattr);
2574 		vattr.va_atime = ts[0];
2575 		vattr.va_mtime = ts[1];
2576 		if (nullflag)
2577 			vattr.va_vaflags |= VA_UTIMES_NULL;
2578 		error = VOP_SETATTR(vp, &vattr, p->p_ucred);
2579 		vput(vp);
2580 	}
2581 	return error;
2582 }
2583 
2584 int
2585 kern_utimes(struct nlookupdata *nd, struct timeval *tptr)
2586 {
2587 	struct timespec ts[2];
2588 	struct vnode *vp;
2589 	int error;
2590 
2591 	if ((error = getutimes(tptr, ts)) != 0)
2592 		return (error);
2593 	/* XXX Add NLC flag indicating modifying operation? */
2594 	if ((error = nlookup(nd)) != 0)
2595 		return (error);
2596 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2597 		return (error);
2598 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
2599 		return (error);
2600 	error = setutimes(vp, ts, tptr == NULL);
2601 	vrele(vp);
2602 	return (error);
2603 }
2604 
2605 /*
2606  * utimes_args(char *path, struct timeval *tptr)
2607  *
2608  * Set the access and modification times of a file.
2609  */
2610 int
2611 sys_utimes(struct utimes_args *uap)
2612 {
2613 	struct timeval tv[2];
2614 	struct nlookupdata nd;
2615 	int error;
2616 
2617 	if (uap->tptr) {
2618  		error = copyin(uap->tptr, tv, sizeof(tv));
2619 		if (error)
2620 			return (error);
2621 	}
2622 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2623 	if (error == 0)
2624 		error = kern_utimes(&nd, uap->tptr ? tv : NULL);
2625 	nlookup_done(&nd);
2626 	return (error);
2627 }
2628 
2629 /*
2630  * lutimes_args(char *path, struct timeval *tptr)
2631  *
2632  * Set the access and modification times of a file.
2633  */
2634 int
2635 sys_lutimes(struct lutimes_args *uap)
2636 {
2637 	struct timeval tv[2];
2638 	struct nlookupdata nd;
2639 	int error;
2640 
2641 	if (uap->tptr) {
2642 		error = copyin(uap->tptr, tv, sizeof(tv));
2643 		if (error)
2644 			return (error);
2645 	}
2646 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2647 	if (error == 0)
2648 		error = kern_utimes(&nd, uap->tptr ? tv : NULL);
2649 	nlookup_done(&nd);
2650 	return (error);
2651 }
2652 
2653 int
2654 kern_futimes(int fd, struct timeval *tptr)
2655 {
2656 	struct thread *td = curthread;
2657 	struct proc *p = td->td_proc;
2658 	struct timespec ts[2];
2659 	struct file *fp;
2660 	int error;
2661 
2662 	error = getutimes(tptr, ts);
2663 	if (error)
2664 		return (error);
2665 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
2666 		return (error);
2667 	if (fp->f_nchandle.ncp)
2668 		error = ncp_writechk(&fp->f_nchandle);
2669 	if (error == 0)
2670 		error =  setutimes((struct vnode *)fp->f_data, ts, tptr == NULL);
2671 	fdrop(fp);
2672 	return (error);
2673 }
2674 
2675 /*
2676  * futimes_args(int fd, struct timeval *tptr)
2677  *
2678  * Set the access and modification times of a file.
2679  */
2680 int
2681 sys_futimes(struct futimes_args *uap)
2682 {
2683 	struct timeval tv[2];
2684 	int error;
2685 
2686 	if (uap->tptr) {
2687 		error = copyin(uap->tptr, tv, sizeof(tv));
2688 		if (error)
2689 			return (error);
2690 	}
2691 
2692 	error = kern_futimes(uap->fd, uap->tptr ? tv : NULL);
2693 
2694 	return (error);
2695 }
2696 
2697 int
2698 kern_truncate(struct nlookupdata *nd, off_t length)
2699 {
2700 	struct vnode *vp;
2701 	struct vattr vattr;
2702 	int error;
2703 
2704 	if (length < 0)
2705 		return(EINVAL);
2706 	/* XXX Add NLC flag indicating modifying operation? */
2707 	if ((error = nlookup(nd)) != 0)
2708 		return (error);
2709 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2710 		return (error);
2711 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
2712 		return (error);
2713 	if ((error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY)) != 0) {
2714 		vrele(vp);
2715 		return (error);
2716 	}
2717 	if (vp->v_type == VDIR) {
2718 		error = EISDIR;
2719 	} else if ((error = vn_writechk(vp, &nd->nl_nch)) == 0 &&
2720 	    (error = VOP_ACCESS(vp, VWRITE, nd->nl_cred)) == 0) {
2721 		VATTR_NULL(&vattr);
2722 		vattr.va_size = length;
2723 		error = VOP_SETATTR(vp, &vattr, nd->nl_cred);
2724 	}
2725 	vput(vp);
2726 	return (error);
2727 }
2728 
2729 /*
2730  * truncate(char *path, int pad, off_t length)
2731  *
2732  * Truncate a file given its path name.
2733  */
2734 int
2735 sys_truncate(struct truncate_args *uap)
2736 {
2737 	struct nlookupdata nd;
2738 	int error;
2739 
2740 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2741 	if (error == 0)
2742 		error = kern_truncate(&nd, uap->length);
2743 	nlookup_done(&nd);
2744 	return error;
2745 }
2746 
2747 int
2748 kern_ftruncate(int fd, off_t length)
2749 {
2750 	struct thread *td = curthread;
2751 	struct proc *p = td->td_proc;
2752 	struct vattr vattr;
2753 	struct vnode *vp;
2754 	struct file *fp;
2755 	int error;
2756 
2757 	if (length < 0)
2758 		return(EINVAL);
2759 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
2760 		return (error);
2761 	if (fp->f_nchandle.ncp) {
2762 		error = ncp_writechk(&fp->f_nchandle);
2763 		if (error)
2764 			goto done;
2765 	}
2766 	if ((fp->f_flag & FWRITE) == 0) {
2767 		error = EINVAL;
2768 		goto done;
2769 	}
2770 	vp = (struct vnode *)fp->f_data;
2771 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2772 	if (vp->v_type == VDIR) {
2773 		error = EISDIR;
2774 	} else if ((error = vn_writechk(vp, NULL)) == 0) {
2775 		VATTR_NULL(&vattr);
2776 		vattr.va_size = length;
2777 		error = VOP_SETATTR(vp, &vattr, fp->f_cred);
2778 	}
2779 	vn_unlock(vp);
2780 done:
2781 	fdrop(fp);
2782 	return (error);
2783 }
2784 
2785 /*
2786  * ftruncate_args(int fd, int pad, off_t length)
2787  *
2788  * Truncate a file given a file descriptor.
2789  */
2790 int
2791 sys_ftruncate(struct ftruncate_args *uap)
2792 {
2793 	int error;
2794 
2795 	error = kern_ftruncate(uap->fd, uap->length);
2796 
2797 	return (error);
2798 }
2799 
2800 /*
2801  * fsync(int fd)
2802  *
2803  * Sync an open file.
2804  */
2805 /* ARGSUSED */
2806 int
2807 sys_fsync(struct fsync_args *uap)
2808 {
2809 	struct thread *td = curthread;
2810 	struct proc *p = td->td_proc;
2811 	struct vnode *vp;
2812 	struct file *fp;
2813 	vm_object_t obj;
2814 	int error;
2815 
2816 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
2817 		return (error);
2818 	vp = (struct vnode *)fp->f_data;
2819 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2820 	if ((obj = vp->v_object) != NULL)
2821 		vm_object_page_clean(obj, 0, 0, 0);
2822 	if ((error = VOP_FSYNC(vp, MNT_WAIT)) == 0 &&
2823 	    vp->v_mount && (vp->v_mount->mnt_flag & MNT_SOFTDEP) &&
2824 	    bioops.io_fsync) {
2825 		error = (*bioops.io_fsync)(vp);
2826 	}
2827 	vn_unlock(vp);
2828 	fdrop(fp);
2829 	return (error);
2830 }
2831 
2832 int
2833 kern_rename(struct nlookupdata *fromnd, struct nlookupdata *tond)
2834 {
2835 	struct nchandle fnchd;
2836 	struct nchandle tnchd;
2837 	struct namecache *ncp;
2838 	struct mount *mp;
2839 	int error;
2840 
2841 	bwillwrite();
2842 	if ((error = nlookup(fromnd)) != 0)
2843 		return (error);
2844 	if ((fnchd.ncp = fromnd->nl_nch.ncp->nc_parent) == NULL)
2845 		return (ENOENT);
2846 	fnchd.mount = fromnd->nl_nch.mount;
2847 	cache_hold(&fnchd);
2848 
2849 	/*
2850 	 * unlock the source nch so we can lookup the target nch without
2851 	 * deadlocking.  The target may or may not exist so we do not check
2852 	 * for a target vp like kern_mkdir() and other creation functions do.
2853 	 *
2854 	 * The source and target directories are ref'd and rechecked after
2855 	 * everything is relocked to determine if the source or target file
2856 	 * has been renamed.
2857 	 */
2858 	KKASSERT(fromnd->nl_flags & NLC_NCPISLOCKED);
2859 	fromnd->nl_flags &= ~NLC_NCPISLOCKED;
2860 	cache_unlock(&fromnd->nl_nch);
2861 
2862 	tond->nl_flags |= NLC_CREATE;
2863 	if ((error = nlookup(tond)) != 0) {
2864 		cache_drop(&fnchd);
2865 		return (error);
2866 	}
2867 	if ((tnchd.ncp = tond->nl_nch.ncp->nc_parent) == NULL) {
2868 		cache_drop(&fnchd);
2869 		return (ENOENT);
2870 	}
2871 	tnchd.mount = tond->nl_nch.mount;
2872 	cache_hold(&tnchd);
2873 
2874 	/*
2875 	 * If the source and target are the same there is nothing to do
2876 	 */
2877 	if (fromnd->nl_nch.ncp == tond->nl_nch.ncp) {
2878 		cache_drop(&fnchd);
2879 		cache_drop(&tnchd);
2880 		return (0);
2881 	}
2882 
2883 	/*
2884 	 * Mount points cannot be renamed or overwritten
2885 	 */
2886 	if ((fromnd->nl_nch.ncp->nc_flag | tond->nl_nch.ncp->nc_flag) &
2887 	    NCF_ISMOUNTPT
2888 	) {
2889 		cache_drop(&fnchd);
2890 		cache_drop(&tnchd);
2891 		return (EINVAL);
2892 	}
2893 
2894 	/*
2895 	 * relock the source ncp.  NOTE AFTER RELOCKING: the source ncp
2896 	 * may have become invalid while it was unlocked, nc_vp and nc_mount
2897 	 * could be NULL.
2898 	 */
2899 	if (cache_lock_nonblock(&fromnd->nl_nch) == 0) {
2900 		cache_resolve(&fromnd->nl_nch, fromnd->nl_cred);
2901 	} else if (fromnd->nl_nch.ncp > tond->nl_nch.ncp) {
2902 		cache_lock(&fromnd->nl_nch);
2903 		cache_resolve(&fromnd->nl_nch, fromnd->nl_cred);
2904 	} else {
2905 		cache_unlock(&tond->nl_nch);
2906 		cache_lock(&fromnd->nl_nch);
2907 		cache_resolve(&fromnd->nl_nch, fromnd->nl_cred);
2908 		cache_lock(&tond->nl_nch);
2909 		cache_resolve(&tond->nl_nch, tond->nl_cred);
2910 	}
2911 	fromnd->nl_flags |= NLC_NCPISLOCKED;
2912 
2913 	/*
2914 	 * make sure the parent directories linkages are the same
2915 	 */
2916 	if (fnchd.ncp != fromnd->nl_nch.ncp->nc_parent ||
2917 	    tnchd.ncp != tond->nl_nch.ncp->nc_parent) {
2918 		cache_drop(&fnchd);
2919 		cache_drop(&tnchd);
2920 		return (ENOENT);
2921 	}
2922 
2923 	/*
2924 	 * Both the source and target must be within the same filesystem and
2925 	 * in the same filesystem as their parent directories within the
2926 	 * namecache topology.
2927 	 *
2928 	 * NOTE: fromnd's nc_mount or nc_vp could be NULL.
2929 	 */
2930 	mp = fnchd.mount;
2931 	if (mp != tnchd.mount || mp != fromnd->nl_nch.mount ||
2932 	    mp != tond->nl_nch.mount) {
2933 		cache_drop(&fnchd);
2934 		cache_drop(&tnchd);
2935 		return (EXDEV);
2936 	}
2937 
2938 	/*
2939 	 * Make sure the mount point is writable
2940 	 */
2941 	if ((error = ncp_writechk(&tond->nl_nch)) != 0) {
2942 		cache_drop(&fnchd);
2943 		cache_drop(&tnchd);
2944 		return (error);
2945 	}
2946 
2947 	/*
2948 	 * If the target exists and either the source or target is a directory,
2949 	 * then both must be directories.
2950 	 *
2951 	 * Due to relocking of the source, fromnd->nl_nch.ncp->nc_vp might h
2952 	 * have become NULL.
2953 	 */
2954 	if (tond->nl_nch.ncp->nc_vp) {
2955 		if (fromnd->nl_nch.ncp->nc_vp == NULL) {
2956 			error = ENOENT;
2957 		} else if (fromnd->nl_nch.ncp->nc_vp->v_type == VDIR) {
2958 			if (tond->nl_nch.ncp->nc_vp->v_type != VDIR)
2959 				error = ENOTDIR;
2960 		} else if (tond->nl_nch.ncp->nc_vp->v_type == VDIR) {
2961 			error = EISDIR;
2962 		}
2963 	}
2964 
2965 	/*
2966 	 * You cannot rename a source into itself or a subdirectory of itself.
2967 	 * We check this by travsersing the target directory upwards looking
2968 	 * for a match against the source.
2969 	 */
2970 	if (error == 0) {
2971 		for (ncp = tnchd.ncp; ncp; ncp = ncp->nc_parent) {
2972 			if (fromnd->nl_nch.ncp == ncp) {
2973 				error = EINVAL;
2974 				break;
2975 			}
2976 		}
2977 	}
2978 
2979 	cache_drop(&fnchd);
2980 	cache_drop(&tnchd);
2981 
2982 	/*
2983 	 * Even though the namespaces are different, they may still represent
2984 	 * hardlinks to the same file.  The filesystem might have a hard time
2985 	 * with this so we issue a NREMOVE of the source instead of a NRENAME
2986 	 * when we detect the situation.
2987 	 */
2988 	if (error == 0) {
2989 		if (fromnd->nl_nch.ncp->nc_vp == tond->nl_nch.ncp->nc_vp) {
2990 			error = VOP_NREMOVE(&fromnd->nl_nch, fromnd->nl_cred);
2991 		} else {
2992 			error = VOP_NRENAME(&fromnd->nl_nch, &tond->nl_nch,
2993 					    tond->nl_cred);
2994 		}
2995 	}
2996 	return (error);
2997 }
2998 
2999 /*
3000  * rename_args(char *from, char *to)
3001  *
3002  * Rename files.  Source and destination must either both be directories,
3003  * or both not be directories.  If target is a directory, it must be empty.
3004  */
3005 int
3006 sys_rename(struct rename_args *uap)
3007 {
3008 	struct nlookupdata fromnd, tond;
3009 	int error;
3010 
3011 	error = nlookup_init(&fromnd, uap->from, UIO_USERSPACE, 0);
3012 	if (error == 0) {
3013 		error = nlookup_init(&tond, uap->to, UIO_USERSPACE, 0);
3014 		if (error == 0)
3015 			error = kern_rename(&fromnd, &tond);
3016 		nlookup_done(&tond);
3017 	}
3018 	nlookup_done(&fromnd);
3019 	return (error);
3020 }
3021 
3022 int
3023 kern_mkdir(struct nlookupdata *nd, int mode)
3024 {
3025 	struct thread *td = curthread;
3026 	struct proc *p = td->td_proc;
3027 	struct vnode *vp;
3028 	struct vattr vattr;
3029 	int error;
3030 
3031 	bwillwrite();
3032 	nd->nl_flags |= NLC_WILLBEDIR | NLC_CREATE;
3033 	if ((error = nlookup(nd)) != 0)
3034 		return (error);
3035 
3036 	if (nd->nl_nch.ncp->nc_vp)
3037 		return (EEXIST);
3038 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3039 		return (error);
3040 
3041 	VATTR_NULL(&vattr);
3042 	vattr.va_type = VDIR;
3043 	vattr.va_mode = (mode & ACCESSPERMS) &~ p->p_fd->fd_cmask;
3044 
3045 	vp = NULL;
3046 	error = VOP_NMKDIR(&nd->nl_nch, &vp, p->p_ucred, &vattr);
3047 	if (error == 0)
3048 		vput(vp);
3049 	return (error);
3050 }
3051 
3052 /*
3053  * mkdir_args(char *path, int mode)
3054  *
3055  * Make a directory file.
3056  */
3057 /* ARGSUSED */
3058 int
3059 sys_mkdir(struct mkdir_args *uap)
3060 {
3061 	struct nlookupdata nd;
3062 	int error;
3063 
3064 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3065 	if (error == 0)
3066 		error = kern_mkdir(&nd, uap->mode);
3067 	nlookup_done(&nd);
3068 	return (error);
3069 }
3070 
3071 int
3072 kern_rmdir(struct nlookupdata *nd)
3073 {
3074 	int error;
3075 
3076 	bwillwrite();
3077 	nd->nl_flags |= NLC_DELETE;
3078 	if ((error = nlookup(nd)) != 0)
3079 		return (error);
3080 
3081 	/*
3082 	 * Do not allow directories representing mount points to be
3083 	 * deleted, even if empty.  Check write perms on mount point
3084 	 * in case the vnode is aliased (aka nullfs).
3085 	 */
3086 	if (nd->nl_nch.ncp->nc_flag & (NCF_ISMOUNTPT))
3087 		return (EINVAL);
3088 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3089 		return (error);
3090 
3091 	error = VOP_NRMDIR(&nd->nl_nch, nd->nl_cred);
3092 	return (error);
3093 }
3094 
3095 /*
3096  * rmdir_args(char *path)
3097  *
3098  * Remove a directory file.
3099  */
3100 /* ARGSUSED */
3101 int
3102 sys_rmdir(struct rmdir_args *uap)
3103 {
3104 	struct nlookupdata nd;
3105 	int error;
3106 
3107 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3108 	if (error == 0)
3109 		error = kern_rmdir(&nd);
3110 	nlookup_done(&nd);
3111 	return (error);
3112 }
3113 
3114 int
3115 kern_getdirentries(int fd, char *buf, u_int count, long *basep, int *res,
3116     enum uio_seg direction)
3117 {
3118 	struct thread *td = curthread;
3119 	struct proc *p = td->td_proc;
3120 	struct vnode *vp;
3121 	struct file *fp;
3122 	struct uio auio;
3123 	struct iovec aiov;
3124 	long loff;
3125 	int error, eofflag;
3126 
3127 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
3128 		return (error);
3129 	if ((fp->f_flag & FREAD) == 0) {
3130 		error = EBADF;
3131 		goto done;
3132 	}
3133 	vp = (struct vnode *)fp->f_data;
3134 unionread:
3135 	if (vp->v_type != VDIR) {
3136 		error = EINVAL;
3137 		goto done;
3138 	}
3139 	aiov.iov_base = buf;
3140 	aiov.iov_len = count;
3141 	auio.uio_iov = &aiov;
3142 	auio.uio_iovcnt = 1;
3143 	auio.uio_rw = UIO_READ;
3144 	auio.uio_segflg = direction;
3145 	auio.uio_td = td;
3146 	auio.uio_resid = count;
3147 	loff = auio.uio_offset = fp->f_offset;
3148 	error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, NULL, NULL);
3149 	fp->f_offset = auio.uio_offset;
3150 	if (error)
3151 		goto done;
3152 	if (count == auio.uio_resid) {
3153 		if (union_dircheckp) {
3154 			error = union_dircheckp(td, &vp, fp);
3155 			if (error == -1)
3156 				goto unionread;
3157 			if (error)
3158 				goto done;
3159 		}
3160 #if 0
3161 		if ((vp->v_flag & VROOT) &&
3162 		    (vp->v_mount->mnt_flag & MNT_UNION)) {
3163 			struct vnode *tvp = vp;
3164 			vp = vp->v_mount->mnt_vnodecovered;
3165 			vref(vp);
3166 			fp->f_data = vp;
3167 			fp->f_offset = 0;
3168 			vrele(tvp);
3169 			goto unionread;
3170 		}
3171 #endif
3172 	}
3173 	if (basep) {
3174 		*basep = loff;
3175 	}
3176 	*res = count - auio.uio_resid;
3177 done:
3178 	fdrop(fp);
3179 	return (error);
3180 }
3181 
3182 /*
3183  * getdirentries_args(int fd, char *buf, u_int conut, long *basep)
3184  *
3185  * Read a block of directory entries in a file system independent format.
3186  */
3187 int
3188 sys_getdirentries(struct getdirentries_args *uap)
3189 {
3190 	long base;
3191 	int error;
3192 
3193 	error = kern_getdirentries(uap->fd, uap->buf, uap->count, &base,
3194 	    &uap->sysmsg_result, UIO_USERSPACE);
3195 
3196 	if (error == 0)
3197 		error = copyout(&base, uap->basep, sizeof(*uap->basep));
3198 	return (error);
3199 }
3200 
3201 /*
3202  * getdents_args(int fd, char *buf, size_t count)
3203  */
3204 int
3205 sys_getdents(struct getdents_args *uap)
3206 {
3207 	int error;
3208 
3209 	error = kern_getdirentries(uap->fd, uap->buf, uap->count, NULL,
3210 	    &uap->sysmsg_result, UIO_USERSPACE);
3211 
3212 	return (error);
3213 }
3214 
3215 /*
3216  * umask(int newmask)
3217  *
3218  * Set the mode mask for creation of filesystem nodes.
3219  *
3220  * MP SAFE
3221  */
3222 int
3223 sys_umask(struct umask_args *uap)
3224 {
3225 	struct thread *td = curthread;
3226 	struct proc *p = td->td_proc;
3227 	struct filedesc *fdp;
3228 
3229 	fdp = p->p_fd;
3230 	uap->sysmsg_result = fdp->fd_cmask;
3231 	fdp->fd_cmask = uap->newmask & ALLPERMS;
3232 	return (0);
3233 }
3234 
3235 /*
3236  * revoke(char *path)
3237  *
3238  * Void all references to file by ripping underlying filesystem
3239  * away from vnode.
3240  */
3241 /* ARGSUSED */
3242 int
3243 sys_revoke(struct revoke_args *uap)
3244 {
3245 	struct nlookupdata nd;
3246 	struct vattr vattr;
3247 	struct vnode *vp;
3248 	struct ucred *cred;
3249 	int error;
3250 
3251 	vp = NULL;
3252 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3253 	if (error == 0)
3254 		error = nlookup(&nd);
3255 	if (error == 0)
3256 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
3257 	cred = crhold(nd.nl_cred);
3258 	nlookup_done(&nd);
3259 	if (error == 0) {
3260 		if (vp->v_type != VCHR && vp->v_type != VBLK)
3261 			error = EINVAL;
3262 		if (error == 0)
3263 			error = VOP_GETATTR(vp, &vattr);
3264 		if (error == 0 && cred->cr_uid != vattr.va_uid)
3265 			error = suser_cred(cred, PRISON_ROOT);
3266 		if (error == 0 && count_udev(vp->v_udev) > 0) {
3267 			error = 0;
3268 			vx_lock(vp);
3269 			VOP_REVOKE(vp, REVOKEALL);
3270 			vx_unlock(vp);
3271 		}
3272 		vrele(vp);
3273 	}
3274 	if (cred)
3275 		crfree(cred);
3276 	return (error);
3277 }
3278 
3279 /*
3280  * getfh_args(char *fname, fhandle_t *fhp)
3281  *
3282  * Get (NFS) file handle
3283  */
3284 int
3285 sys_getfh(struct getfh_args *uap)
3286 {
3287 	struct thread *td = curthread;
3288 	struct nlookupdata nd;
3289 	fhandle_t fh;
3290 	struct vnode *vp;
3291 	int error;
3292 
3293 	/*
3294 	 * Must be super user
3295 	 */
3296 	if ((error = suser(td)) != 0)
3297 		return (error);
3298 
3299 	vp = NULL;
3300 	error = nlookup_init(&nd, uap->fname, UIO_USERSPACE, NLC_FOLLOW);
3301 	if (error == 0)
3302 		error = nlookup(&nd);
3303 	if (error == 0)
3304 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
3305 	nlookup_done(&nd);
3306 	if (error == 0) {
3307 		bzero(&fh, sizeof(fh));
3308 		fh.fh_fsid = vp->v_mount->mnt_stat.f_fsid;
3309 		error = VFS_VPTOFH(vp, &fh.fh_fid);
3310 		vput(vp);
3311 		if (error == 0)
3312 			error = copyout(&fh, uap->fhp, sizeof(fh));
3313 	}
3314 	return (error);
3315 }
3316 
3317 /*
3318  * fhopen_args(const struct fhandle *u_fhp, int flags)
3319  *
3320  * syscall for the rpc.lockd to use to translate a NFS file handle into
3321  * an open descriptor.
3322  *
3323  * warning: do not remove the suser() call or this becomes one giant
3324  * security hole.
3325  */
3326 int
3327 sys_fhopen(struct fhopen_args *uap)
3328 {
3329 	struct thread *td = curthread;
3330 	struct proc *p = td->td_proc;
3331 	struct mount *mp;
3332 	struct vnode *vp;
3333 	struct fhandle fhp;
3334 	struct vattr vat;
3335 	struct vattr *vap = &vat;
3336 	struct flock lf;
3337 	int fmode, mode, error, type;
3338 	struct file *nfp;
3339 	struct file *fp;
3340 	int indx;
3341 
3342 	/*
3343 	 * Must be super user
3344 	 */
3345 	error = suser(td);
3346 	if (error)
3347 		return (error);
3348 
3349 	fmode = FFLAGS(uap->flags);
3350 	/* why not allow a non-read/write open for our lockd? */
3351 	if (((fmode & (FREAD | FWRITE)) == 0) || (fmode & O_CREAT))
3352 		return (EINVAL);
3353 	error = copyin(uap->u_fhp, &fhp, sizeof(fhp));
3354 	if (error)
3355 		return(error);
3356 	/* find the mount point */
3357 	mp = vfs_getvfs(&fhp.fh_fsid);
3358 	if (mp == NULL)
3359 		return (ESTALE);
3360 	/* now give me my vnode, it gets returned to me locked */
3361 	error = VFS_FHTOVP(mp, &fhp.fh_fid, &vp);
3362 	if (error)
3363 		return (error);
3364  	/*
3365 	 * from now on we have to make sure not
3366 	 * to forget about the vnode
3367 	 * any error that causes an abort must vput(vp)
3368 	 * just set error = err and 'goto bad;'.
3369 	 */
3370 
3371 	/*
3372 	 * from vn_open
3373 	 */
3374 	if (vp->v_type == VLNK) {
3375 		error = EMLINK;
3376 		goto bad;
3377 	}
3378 	if (vp->v_type == VSOCK) {
3379 		error = EOPNOTSUPP;
3380 		goto bad;
3381 	}
3382 	mode = 0;
3383 	if (fmode & (FWRITE | O_TRUNC)) {
3384 		if (vp->v_type == VDIR) {
3385 			error = EISDIR;
3386 			goto bad;
3387 		}
3388 		error = vn_writechk(vp, NULL);
3389 		if (error)
3390 			goto bad;
3391 		mode |= VWRITE;
3392 	}
3393 	if (fmode & FREAD)
3394 		mode |= VREAD;
3395 	if (mode) {
3396 		error = VOP_ACCESS(vp, mode, p->p_ucred);
3397 		if (error)
3398 			goto bad;
3399 	}
3400 	if (fmode & O_TRUNC) {
3401 		vn_unlock(vp);				/* XXX */
3402 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);	/* XXX */
3403 		VATTR_NULL(vap);
3404 		vap->va_size = 0;
3405 		error = VOP_SETATTR(vp, vap, p->p_ucred);
3406 		if (error)
3407 			goto bad;
3408 	}
3409 
3410 	/*
3411 	 * VOP_OPEN needs the file pointer so it can potentially override
3412 	 * it.
3413 	 *
3414 	 * WARNING! no f_nchandle will be associated when fhopen()ing a
3415 	 * directory.  XXX
3416 	 */
3417 	if ((error = falloc(p, &nfp, &indx)) != 0)
3418 		goto bad;
3419 	fp = nfp;
3420 
3421 	error = VOP_OPEN(vp, fmode, p->p_ucred, fp);
3422 	if (error) {
3423 		/*
3424 		 * setting f_ops this way prevents VOP_CLOSE from being
3425 		 * called or fdrop() releasing the vp from v_data.   Since
3426 		 * the VOP_OPEN failed we don't want to VOP_CLOSE.
3427 		 */
3428 		fp->f_ops = &badfileops;
3429 		fp->f_data = NULL;
3430 		goto bad_drop;
3431 	}
3432 
3433 	/*
3434 	 * The fp is given its own reference, we still have our ref and lock.
3435 	 *
3436 	 * Assert that all regular files must be created with a VM object.
3437 	 */
3438 	if (vp->v_type == VREG && vp->v_object == NULL) {
3439 		kprintf("fhopen: regular file did not have VM object: %p\n", vp);
3440 		goto bad_drop;
3441 	}
3442 
3443 	/*
3444 	 * The open was successful.  Handle any locking requirements.
3445 	 */
3446 	if (fmode & (O_EXLOCK | O_SHLOCK)) {
3447 		lf.l_whence = SEEK_SET;
3448 		lf.l_start = 0;
3449 		lf.l_len = 0;
3450 		if (fmode & O_EXLOCK)
3451 			lf.l_type = F_WRLCK;
3452 		else
3453 			lf.l_type = F_RDLCK;
3454 		if (fmode & FNONBLOCK)
3455 			type = 0;
3456 		else
3457 			type = F_WAIT;
3458 		vn_unlock(vp);
3459 		if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0) {
3460 			/*
3461 			 * release our private reference.
3462 			 */
3463 			fsetfd(p, NULL, indx);
3464 			fdrop(fp);
3465 			vrele(vp);
3466 			return (error);
3467 		}
3468 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3469 		fp->f_flag |= FHASLOCK;
3470 	}
3471 
3472 	/*
3473 	 * Clean up.  Associate the file pointer with the previously
3474 	 * reserved descriptor and return it.
3475 	 */
3476 	vput(vp);
3477 	fsetfd(p, fp, indx);
3478 	fdrop(fp);
3479 	uap->sysmsg_result = indx;
3480 	return (0);
3481 
3482 bad_drop:
3483 	fsetfd(p, NULL, indx);
3484 	fdrop(fp);
3485 bad:
3486 	vput(vp);
3487 	return (error);
3488 }
3489 
3490 /*
3491  * fhstat_args(struct fhandle *u_fhp, struct stat *sb)
3492  */
3493 int
3494 sys_fhstat(struct fhstat_args *uap)
3495 {
3496 	struct thread *td = curthread;
3497 	struct stat sb;
3498 	fhandle_t fh;
3499 	struct mount *mp;
3500 	struct vnode *vp;
3501 	int error;
3502 
3503 	/*
3504 	 * Must be super user
3505 	 */
3506 	error = suser(td);
3507 	if (error)
3508 		return (error);
3509 
3510 	error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t));
3511 	if (error)
3512 		return (error);
3513 
3514 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL)
3515 		return (ESTALE);
3516 	if ((error = VFS_FHTOVP(mp, &fh.fh_fid, &vp)))
3517 		return (error);
3518 	error = vn_stat(vp, &sb, td->td_proc->p_ucred);
3519 	vput(vp);
3520 	if (error)
3521 		return (error);
3522 	error = copyout(&sb, uap->sb, sizeof(sb));
3523 	return (error);
3524 }
3525 
3526 /*
3527  * fhstatfs_args(struct fhandle *u_fhp, struct statfs *buf)
3528  */
3529 int
3530 sys_fhstatfs(struct fhstatfs_args *uap)
3531 {
3532 	struct thread *td = curthread;
3533 	struct proc *p = td->td_proc;
3534 	struct statfs *sp;
3535 	struct mount *mp;
3536 	struct vnode *vp;
3537 	struct statfs sb;
3538 	char *fullpath, *freepath;
3539 	fhandle_t fh;
3540 	int error;
3541 
3542 	/*
3543 	 * Must be super user
3544 	 */
3545 	if ((error = suser(td)))
3546 		return (error);
3547 
3548 	if ((error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t))) != 0)
3549 		return (error);
3550 
3551 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL)
3552 		return (ESTALE);
3553 
3554 	if (p != NULL && !chroot_visible_mnt(mp, p))
3555 		return (ESTALE);
3556 
3557 	if ((error = VFS_FHTOVP(mp, &fh.fh_fid, &vp)))
3558 		return (error);
3559 	mp = vp->v_mount;
3560 	sp = &mp->mnt_stat;
3561 	vput(vp);
3562 	if ((error = VFS_STATFS(mp, sp, p->p_ucred)) != 0)
3563 		return (error);
3564 
3565 	error = mount_path(p, mp, &fullpath, &freepath);
3566 	if (error)
3567 		return(error);
3568 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
3569 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
3570 	kfree(freepath, M_TEMP);
3571 
3572 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
3573 	if (suser(td)) {
3574 		bcopy(sp, &sb, sizeof(sb));
3575 		sb.f_fsid.val[0] = sb.f_fsid.val[1] = 0;
3576 		sp = &sb;
3577 	}
3578 	return (copyout(sp, uap->buf, sizeof(*sp)));
3579 }
3580 
3581 /*
3582  * Syscall to push extended attribute configuration information into the
3583  * VFS.  Accepts a path, which it converts to a mountpoint, as well as
3584  * a command (int cmd), and attribute name and misc data.  For now, the
3585  * attribute name is left in userspace for consumption by the VFS_op.
3586  * It will probably be changed to be copied into sysspace by the
3587  * syscall in the future, once issues with various consumers of the
3588  * attribute code have raised their hands.
3589  *
3590  * Currently this is used only by UFS Extended Attributes.
3591  */
3592 int
3593 sys_extattrctl(struct extattrctl_args *uap)
3594 {
3595 	struct nlookupdata nd;
3596 	struct mount *mp;
3597 	struct vnode *vp;
3598 	int error;
3599 
3600 	vp = NULL;
3601 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3602 	if (error == 0)
3603 		error = nlookup(&nd);
3604 	if (error == 0) {
3605 		mp = nd.nl_nch.mount;
3606 		error = VFS_EXTATTRCTL(mp, uap->cmd,
3607 				uap->attrname, uap->arg,
3608 				nd.nl_cred);
3609 	}
3610 	nlookup_done(&nd);
3611 	return (error);
3612 }
3613 
3614 /*
3615  * Syscall to set a named extended attribute on a file or directory.
3616  * Accepts attribute name, and a uio structure pointing to the data to set.
3617  * The uio is consumed in the style of writev().  The real work happens
3618  * in VOP_SETEXTATTR().
3619  */
3620 int
3621 sys_extattr_set_file(struct extattr_set_file_args *uap)
3622 {
3623 	char attrname[EXTATTR_MAXNAMELEN];
3624 	struct iovec aiov[UIO_SMALLIOV];
3625 	struct iovec *needfree;
3626 	struct nlookupdata nd;
3627 	struct iovec *iov;
3628 	struct vnode *vp;
3629 	struct uio auio;
3630 	u_int iovlen;
3631 	u_int cnt;
3632 	int error;
3633 	int i;
3634 
3635 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
3636 	if (error)
3637 		return (error);
3638 
3639 	vp = NULL;
3640 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3641 	if (error == 0)
3642 		error = nlookup(&nd);
3643 	if (error == 0)
3644 		error = ncp_writechk(&nd.nl_nch);
3645 	if (error == 0)
3646 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
3647 	if (error) {
3648 		nlookup_done(&nd);
3649 		return (error);
3650 	}
3651 
3652 	needfree = NULL;
3653 	iovlen = uap->iovcnt * sizeof(struct iovec);
3654 	if (uap->iovcnt > UIO_SMALLIOV) {
3655 		if (uap->iovcnt > UIO_MAXIOV) {
3656 			error = EINVAL;
3657 			goto done;
3658 		}
3659 		MALLOC(iov, struct iovec *, iovlen, M_IOV, M_WAITOK);
3660 		needfree = iov;
3661 	} else {
3662 		iov = aiov;
3663 	}
3664 	auio.uio_iov = iov;
3665 	auio.uio_iovcnt = uap->iovcnt;
3666 	auio.uio_rw = UIO_WRITE;
3667 	auio.uio_segflg = UIO_USERSPACE;
3668 	auio.uio_td = nd.nl_td;
3669 	auio.uio_offset = 0;
3670 	if ((error = copyin(uap->iovp, iov, iovlen)))
3671 		goto done;
3672 	auio.uio_resid = 0;
3673 	for (i = 0; i < uap->iovcnt; i++) {
3674 		if (iov->iov_len > INT_MAX - auio.uio_resid) {
3675 			error = EINVAL;
3676 			goto done;
3677 		}
3678 		auio.uio_resid += iov->iov_len;
3679 		iov++;
3680 	}
3681 	cnt = auio.uio_resid;
3682 	error = VOP_SETEXTATTR(vp, attrname, &auio, nd.nl_cred);
3683 	cnt -= auio.uio_resid;
3684 	uap->sysmsg_result = cnt;
3685 done:
3686 	vput(vp);
3687 	nlookup_done(&nd);
3688 	if (needfree)
3689 		FREE(needfree, M_IOV);
3690 	return (error);
3691 }
3692 
3693 /*
3694  * Syscall to get a named extended attribute on a file or directory.
3695  * Accepts attribute name, and a uio structure pointing to a buffer for the
3696  * data.  The uio is consumed in the style of readv().  The real work
3697  * happens in VOP_GETEXTATTR();
3698  */
3699 int
3700 sys_extattr_get_file(struct extattr_get_file_args *uap)
3701 {
3702 	char attrname[EXTATTR_MAXNAMELEN];
3703 	struct iovec aiov[UIO_SMALLIOV];
3704 	struct iovec *needfree;
3705 	struct nlookupdata nd;
3706 	struct iovec *iov;
3707 	struct vnode *vp;
3708 	struct uio auio;
3709 	u_int iovlen;
3710 	u_int cnt;
3711 	int error;
3712 	int i;
3713 
3714 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
3715 	if (error)
3716 		return (error);
3717 
3718 	vp = NULL;
3719 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3720 	if (error == 0)
3721 		error = nlookup(&nd);
3722 	if (error == 0)
3723 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
3724 	if (error) {
3725 		nlookup_done(&nd);
3726 		return (error);
3727 	}
3728 
3729 	iovlen = uap->iovcnt * sizeof (struct iovec);
3730 	needfree = NULL;
3731 	if (uap->iovcnt > UIO_SMALLIOV) {
3732 		if (uap->iovcnt > UIO_MAXIOV) {
3733 			error = EINVAL;
3734 			goto done;
3735 		}
3736 		MALLOC(iov, struct iovec *, iovlen, M_IOV, M_WAITOK);
3737 		needfree = iov;
3738 	} else {
3739 		iov = aiov;
3740 	}
3741 	auio.uio_iov = iov;
3742 	auio.uio_iovcnt = uap->iovcnt;
3743 	auio.uio_rw = UIO_READ;
3744 	auio.uio_segflg = UIO_USERSPACE;
3745 	auio.uio_td = nd.nl_td;
3746 	auio.uio_offset = 0;
3747 	if ((error = copyin(uap->iovp, iov, iovlen)))
3748 		goto done;
3749 	auio.uio_resid = 0;
3750 	for (i = 0; i < uap->iovcnt; i++) {
3751 		if (iov->iov_len > INT_MAX - auio.uio_resid) {
3752 			error = EINVAL;
3753 			goto done;
3754 		}
3755 		auio.uio_resid += iov->iov_len;
3756 		iov++;
3757 	}
3758 	cnt = auio.uio_resid;
3759 	error = VOP_GETEXTATTR(vp, attrname, &auio, nd.nl_cred);
3760 	cnt -= auio.uio_resid;
3761 	uap->sysmsg_result = cnt;
3762 done:
3763 	vput(vp);
3764 	nlookup_done(&nd);
3765 	if (needfree)
3766 		FREE(needfree, M_IOV);
3767 	return(error);
3768 }
3769 
3770 /*
3771  * Syscall to delete a named extended attribute from a file or directory.
3772  * Accepts attribute name.  The real work happens in VOP_SETEXTATTR().
3773  */
3774 int
3775 sys_extattr_delete_file(struct extattr_delete_file_args *uap)
3776 {
3777 	char attrname[EXTATTR_MAXNAMELEN];
3778 	struct nlookupdata nd;
3779 	struct vnode *vp;
3780 	int error;
3781 
3782 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
3783 	if (error)
3784 		return(error);
3785 
3786 	vp = NULL;
3787 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3788 	if (error == 0)
3789 		error = nlookup(&nd);
3790 	if (error == 0)
3791 		error = ncp_writechk(&nd.nl_nch);
3792 	if (error == 0)
3793 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
3794 	if (error) {
3795 		nlookup_done(&nd);
3796 		return (error);
3797 	}
3798 
3799 	error = VOP_SETEXTATTR(vp, attrname, NULL, nd.nl_cred);
3800 	vput(vp);
3801 	nlookup_done(&nd);
3802 	return(error);
3803 }
3804 
3805 /*
3806  * Determine if the mount is visible to the process.
3807  */
3808 static int
3809 chroot_visible_mnt(struct mount *mp, struct proc *p)
3810 {
3811 	struct nchandle nch;
3812 
3813 	/*
3814 	 * Traverse from the mount point upwards.  If we hit the process
3815 	 * root then the mount point is visible to the process.
3816 	 */
3817 	nch = mp->mnt_ncmountpt;
3818 	while (nch.ncp) {
3819 		if (nch.mount == p->p_fd->fd_nrdir.mount &&
3820 		    nch.ncp == p->p_fd->fd_nrdir.ncp) {
3821 			return(1);
3822 		}
3823 		if (nch.ncp == nch.mount->mnt_ncmountpt.ncp) {
3824 			nch = nch.mount->mnt_ncmounton;
3825 		} else {
3826 			nch.ncp = nch.ncp->nc_parent;
3827 		}
3828 	}
3829 
3830 	/*
3831 	 * If the mount point is not visible to the process, but the
3832 	 * process root is in a subdirectory of the mount, return
3833 	 * TRUE anyway.
3834 	 */
3835 	if (p->p_fd->fd_nrdir.mount == mp)
3836 		return(1);
3837 
3838 	return(0);
3839 }
3840 
3841