xref: /dragonfly/sys/kern/vfs_syscalls.c (revision 9b5ae8ee)
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 1.123 2007/11/20 18:35:46 dillon 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 
70 #include <sys/buf2.h>
71 #include <sys/file2.h>
72 #include <sys/spinlock2.h>
73 
74 #include <vm/vm.h>
75 #include <vm/vm_object.h>
76 #include <vm/vm_page.h>
77 
78 #include <machine/limits.h>
79 #include <machine/stdarg.h>
80 
81 #include <vfs/union/union.h>
82 
83 static void mount_warning(struct mount *mp, const char *ctl, ...);
84 static int mount_path(struct proc *p, struct mount *mp, char **rb, char **fb);
85 static int checkvp_chdir (struct vnode *vn, struct thread *td);
86 static void checkdirs (struct nchandle *old_nch, struct nchandle *new_nch);
87 static int chroot_refuse_vdir_fds (struct filedesc *fdp);
88 static int chroot_visible_mnt(struct mount *mp, struct proc *p);
89 static int getutimes (const struct timeval *, struct timespec *);
90 static int setfown (struct vnode *, uid_t, gid_t);
91 static int setfmode (struct vnode *, int);
92 static int setfflags (struct vnode *, int);
93 static int setutimes (struct vnode *, const struct timespec *, int);
94 static int	usermount = 0;	/* if 1, non-root can mount fs. */
95 
96 int (*union_dircheckp) (struct thread *, struct vnode **, struct file *);
97 
98 SYSCTL_INT(_vfs, OID_AUTO, usermount, CTLFLAG_RW, &usermount, 0, "");
99 
100 /*
101  * Virtual File System System Calls
102  */
103 
104 /*
105  * Mount a file system.
106  */
107 /*
108  * mount_args(char *type, char *path, int flags, caddr_t data)
109  */
110 /* ARGSUSED */
111 int
112 sys_mount(struct mount_args *uap)
113 {
114 	struct thread *td = curthread;
115 	struct proc *p = td->td_proc;
116 	struct vnode *vp;
117 	struct nchandle nch;
118 	struct mount *mp;
119 	struct vfsconf *vfsp;
120 	int error, flag = 0, flag2 = 0;
121 	int hasmount;
122 	struct vattr va;
123 	struct nlookupdata nd;
124 	char fstypename[MFSNAMELEN];
125 	struct ucred *cred = p->p_ucred;
126 
127 	KKASSERT(p);
128 	if (cred->cr_prison != NULL)
129 		return (EPERM);
130 	if (usermount == 0 && (error = suser(td)))
131 		return (error);
132 	/*
133 	 * Do not allow NFS export by non-root users.
134 	 */
135 	if (uap->flags & MNT_EXPORTED) {
136 		error = suser(td);
137 		if (error)
138 			return (error);
139 	}
140 	/*
141 	 * Silently enforce MNT_NOSUID and MNT_NODEV for non-root users
142 	 */
143 	if (suser(td))
144 		uap->flags |= MNT_NOSUID | MNT_NODEV;
145 
146 	/*
147 	 * Lookup the requested path and extract the nch and vnode.
148 	 */
149 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
150 	if (error == 0) {
151 		if ((error = nlookup(&nd)) == 0) {
152 			if (nd.nl_nch.ncp->nc_vp == NULL)
153 				error = ENOENT;
154 		}
155 	}
156 	if (error) {
157 		nlookup_done(&nd);
158 		return (error);
159 	}
160 
161 	/*
162 	 * Extract the locked+refd ncp and cleanup the nd structure
163 	 */
164 	nch = nd.nl_nch;
165 	cache_zero(&nd.nl_nch);
166 	nlookup_done(&nd);
167 
168 	if ((nch.ncp->nc_flag & NCF_ISMOUNTPT) && cache_findmount(&nch))
169 		hasmount = 1;
170 	else
171 		hasmount = 0;
172 
173 
174 	/*
175 	 * now we have the locked ref'd nch and unreferenced vnode.
176 	 */
177 	vp = nch.ncp->nc_vp;
178 	if ((error = vget(vp, LK_EXCLUSIVE)) != 0) {
179 		cache_put(&nch);
180 		return (error);
181 	}
182 	cache_unlock(&nch);
183 
184 	/*
185 	 * Now we have an unlocked ref'd nch and a locked ref'd vp
186 	 */
187 	if (uap->flags & MNT_UPDATE) {
188 		if ((vp->v_flag & VROOT) == 0) {
189 			cache_drop(&nch);
190 			vput(vp);
191 			return (EINVAL);
192 		}
193 		mp = vp->v_mount;
194 		flag = mp->mnt_flag;
195 		flag2 = mp->mnt_kern_flag;
196 		/*
197 		 * We only allow the filesystem to be reloaded if it
198 		 * is currently mounted read-only.
199 		 */
200 		if ((uap->flags & MNT_RELOAD) &&
201 		    ((mp->mnt_flag & MNT_RDONLY) == 0)) {
202 			cache_drop(&nch);
203 			vput(vp);
204 			return (EOPNOTSUPP);	/* Needs translation */
205 		}
206 		/*
207 		 * Only root, or the user that did the original mount is
208 		 * permitted to update it.
209 		 */
210 		if (mp->mnt_stat.f_owner != cred->cr_uid &&
211 		    (error = suser(td))) {
212 			cache_drop(&nch);
213 			vput(vp);
214 			return (error);
215 		}
216 		if (vfs_busy(mp, LK_NOWAIT)) {
217 			cache_drop(&nch);
218 			vput(vp);
219 			return (EBUSY);
220 		}
221 		if ((vp->v_flag & VMOUNT) != 0 || hasmount) {
222 			cache_drop(&nch);
223 			vfs_unbusy(mp);
224 			vput(vp);
225 			return (EBUSY);
226 		}
227 		vp->v_flag |= VMOUNT;
228 		mp->mnt_flag |=
229 		    uap->flags & (MNT_RELOAD | MNT_FORCE | MNT_UPDATE);
230 		vn_unlock(vp);
231 		goto update;
232 	}
233 	/*
234 	 * If the user is not root, ensure that they own the directory
235 	 * onto which we are attempting to mount.
236 	 */
237 	if ((error = VOP_GETATTR(vp, &va)) ||
238 	    (va.va_uid != cred->cr_uid && (error = suser(td)))) {
239 		cache_drop(&nch);
240 		vput(vp);
241 		return (error);
242 	}
243 	if ((error = vinvalbuf(vp, V_SAVE, 0, 0)) != 0) {
244 		cache_drop(&nch);
245 		vput(vp);
246 		return (error);
247 	}
248 	if (vp->v_type != VDIR) {
249 		cache_drop(&nch);
250 		vput(vp);
251 		return (ENOTDIR);
252 	}
253 	if (vp->v_mount->mnt_kern_flag & MNTK_NOSTKMNT) {
254 		cache_drop(&nch);
255 		vput(vp);
256 		return (EPERM);
257 	}
258 	if ((error = copyinstr(uap->type, fstypename, MFSNAMELEN, NULL)) != 0) {
259 		cache_drop(&nch);
260 		vput(vp);
261 		return (error);
262 	}
263 	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
264 		if (!strcmp(vfsp->vfc_name, fstypename))
265 			break;
266 	}
267 	if (vfsp == NULL) {
268 		linker_file_t lf;
269 
270 		/* Only load modules for root (very important!) */
271 		if ((error = suser(td)) != 0) {
272 			cache_drop(&nch);
273 			vput(vp);
274 			return error;
275 		}
276 		error = linker_load_file(fstypename, &lf);
277 		if (error || lf == NULL) {
278 			cache_drop(&nch);
279 			vput(vp);
280 			if (lf == NULL)
281 				error = ENODEV;
282 			return error;
283 		}
284 		lf->userrefs++;
285 		/* lookup again, see if the VFS was loaded */
286 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
287 			if (!strcmp(vfsp->vfc_name, fstypename))
288 				break;
289 		}
290 		if (vfsp == NULL) {
291 			lf->userrefs--;
292 			linker_file_unload(lf);
293 			cache_drop(&nch);
294 			vput(vp);
295 			return (ENODEV);
296 		}
297 	}
298 	if ((vp->v_flag & VMOUNT) != 0 || hasmount) {
299 		cache_drop(&nch);
300 		vput(vp);
301 		return (EBUSY);
302 	}
303 	vp->v_flag |= VMOUNT;
304 
305 	/*
306 	 * Allocate and initialize the filesystem.
307 	 */
308 	mp = kmalloc(sizeof(struct mount), M_MOUNT, M_ZERO|M_WAITOK);
309 	TAILQ_INIT(&mp->mnt_nvnodelist);
310 	TAILQ_INIT(&mp->mnt_reservedvnlist);
311 	TAILQ_INIT(&mp->mnt_jlist);
312 	mp->mnt_nvnodelistsize = 0;
313 	lockinit(&mp->mnt_lock, "vfslock", 0, 0);
314 	vfs_busy(mp, LK_NOWAIT);
315 	mp->mnt_op = vfsp->vfc_vfsops;
316 	mp->mnt_vfc = vfsp;
317 	vfsp->vfc_refcount++;
318 	mp->mnt_stat.f_type = vfsp->vfc_typenum;
319 	mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
320 	strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
321 	mp->mnt_stat.f_owner = cred->cr_uid;
322 	mp->mnt_iosize_max = DFLTPHYS;
323 	vn_unlock(vp);
324 update:
325 	/*
326 	 * Set the mount level flags.
327 	 */
328 	if (uap->flags & MNT_RDONLY)
329 		mp->mnt_flag |= MNT_RDONLY;
330 	else if (mp->mnt_flag & MNT_RDONLY)
331 		mp->mnt_kern_flag |= MNTK_WANTRDWR;
332 	mp->mnt_flag &=~ (MNT_NOSUID | MNT_NOEXEC | MNT_NODEV |
333 	    MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_NOATIME |
334 	    MNT_NOSYMFOLLOW | MNT_IGNORE |
335 	    MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR);
336 	mp->mnt_flag |= uap->flags & (MNT_NOSUID | MNT_NOEXEC |
337 	    MNT_NODEV | MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_FORCE |
338 	    MNT_NOSYMFOLLOW | MNT_IGNORE |
339 	    MNT_NOATIME | MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR);
340 	/*
341 	 * Mount the filesystem.
342 	 * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
343 	 * get.
344 	 */
345 	error = VFS_MOUNT(mp, uap->path, uap->data, cred);
346 	if (mp->mnt_flag & MNT_UPDATE) {
347 		if (mp->mnt_kern_flag & MNTK_WANTRDWR)
348 			mp->mnt_flag &= ~MNT_RDONLY;
349 		mp->mnt_flag &=~ (MNT_UPDATE | MNT_RELOAD | MNT_FORCE);
350 		mp->mnt_kern_flag &=~ MNTK_WANTRDWR;
351 		if (error) {
352 			mp->mnt_flag = flag;
353 			mp->mnt_kern_flag = flag2;
354 		}
355 		vfs_unbusy(mp);
356 		vp->v_flag &= ~VMOUNT;
357 		vrele(vp);
358 		cache_drop(&nch);
359 		return (error);
360 	}
361 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
362 	/*
363 	 * Put the new filesystem on the mount list after root.  The mount
364 	 * point gets its own mnt_ncmountpt (unless the VFS already set one
365 	 * up) which represents the root of the mount.  The lookup code
366 	 * detects the mount point going forward and checks the root of
367 	 * the mount going backwards.
368 	 *
369 	 * It is not necessary to invalidate or purge the vnode underneath
370 	 * because elements under the mount will be given their own glue
371 	 * namecache record.
372 	 */
373 	if (!error) {
374 		if (mp->mnt_ncmountpt.ncp == NULL) {
375 			/*
376 			 * allocate, then unlock, but leave the ref intact
377 			 */
378 			cache_allocroot(&mp->mnt_ncmountpt, mp, NULL);
379 			cache_unlock(&mp->mnt_ncmountpt);
380 		}
381 		mp->mnt_ncmounton = nch;		/* inherits ref */
382 		nch.ncp->nc_flag |= NCF_ISMOUNTPT;
383 
384 		/* XXX get the root of the fs and cache_setvp(mnt_ncmountpt...) */
385 		vp->v_flag &= ~VMOUNT;
386 		mountlist_insert(mp, MNTINS_LAST);
387 		checkdirs(&mp->mnt_ncmounton, &mp->mnt_ncmountpt);
388 		vn_unlock(vp);
389 		error = vfs_allocate_syncvnode(mp);
390 		vfs_unbusy(mp);
391 		error = VFS_START(mp, 0);
392 		vrele(vp);
393 	} else {
394 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
395 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
396 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
397 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
398 		vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
399 		vp->v_flag &= ~VMOUNT;
400 		mp->mnt_vfc->vfc_refcount--;
401 		vfs_unbusy(mp);
402 		kfree(mp, M_MOUNT);
403 		cache_drop(&nch);
404 		vput(vp);
405 	}
406 	return (error);
407 }
408 
409 /*
410  * Scan all active processes to see if any of them have a current
411  * or root directory onto which the new filesystem has just been
412  * mounted. If so, replace them with the new mount point.
413  *
414  * The passed ncp is ref'd and locked (from the mount code) and
415  * must be associated with the vnode representing the root of the
416  * mount point.
417  */
418 struct checkdirs_info {
419 	struct nchandle old_nch;
420 	struct nchandle new_nch;
421 	struct vnode *old_vp;
422 	struct vnode *new_vp;
423 };
424 
425 static int checkdirs_callback(struct proc *p, void *data);
426 
427 static void
428 checkdirs(struct nchandle *old_nch, struct nchandle *new_nch)
429 {
430 	struct checkdirs_info info;
431 	struct vnode *olddp;
432 	struct vnode *newdp;
433 	struct mount *mp;
434 
435 	/*
436 	 * If the old mount point's vnode has a usecount of 1, it is not
437 	 * being held as a descriptor anywhere.
438 	 */
439 	olddp = old_nch->ncp->nc_vp;
440 	if (olddp == NULL || olddp->v_sysref.refcnt == 1)
441 		return;
442 
443 	/*
444 	 * Force the root vnode of the new mount point to be resolved
445 	 * so we can update any matching processes.
446 	 */
447 	mp = new_nch->mount;
448 	if (VFS_ROOT(mp, &newdp))
449 		panic("mount: lost mount");
450 	cache_setunresolved(new_nch);
451 	cache_setvp(new_nch, newdp);
452 
453 	/*
454 	 * Special handling of the root node
455 	 */
456 	if (rootvnode == olddp) {
457 		vref(newdp);
458 		vfs_cache_setroot(newdp, cache_hold(new_nch));
459 	}
460 
461 	/*
462 	 * Pass newdp separately so the callback does not have to access
463 	 * it via new_nch->ncp->nc_vp.
464 	 */
465 	info.old_nch = *old_nch;
466 	info.new_nch = *new_nch;
467 	info.new_vp = newdp;
468 	allproc_scan(checkdirs_callback, &info);
469 	vput(newdp);
470 }
471 
472 /*
473  * NOTE: callback is not MP safe because the scanned process's filedesc
474  * structure can be ripped out from under us, amoung other things.
475  */
476 static int
477 checkdirs_callback(struct proc *p, void *data)
478 {
479 	struct checkdirs_info *info = data;
480 	struct filedesc *fdp;
481 	struct nchandle ncdrop1;
482 	struct nchandle ncdrop2;
483 	struct vnode *vprele1;
484 	struct vnode *vprele2;
485 
486 	if ((fdp = p->p_fd) != NULL) {
487 		cache_zero(&ncdrop1);
488 		cache_zero(&ncdrop2);
489 		vprele1 = NULL;
490 		vprele2 = NULL;
491 
492 		/*
493 		 * MPUNSAFE - XXX fdp can be pulled out from under a
494 		 * foreign process.
495 		 *
496 		 * A shared filedesc is ok, we don't have to copy it
497 		 * because we are making this change globally.
498 		 */
499 		spin_lock_wr(&fdp->fd_spin);
500 		if (fdp->fd_ncdir.mount == info->old_nch.mount &&
501 		    fdp->fd_ncdir.ncp == info->old_nch.ncp) {
502 			vprele1 = fdp->fd_cdir;
503 			vref(info->new_vp);
504 			fdp->fd_cdir = info->new_vp;
505 			ncdrop1 = fdp->fd_ncdir;
506 			cache_copy(&info->new_nch, &fdp->fd_ncdir);
507 		}
508 		if (fdp->fd_nrdir.mount == info->old_nch.mount &&
509 		    fdp->fd_nrdir.ncp == info->old_nch.ncp) {
510 			vprele2 = fdp->fd_rdir;
511 			vref(info->new_vp);
512 			fdp->fd_rdir = info->new_vp;
513 			ncdrop2 = fdp->fd_nrdir;
514 			cache_copy(&info->new_nch, &fdp->fd_nrdir);
515 		}
516 		spin_unlock_wr(&fdp->fd_spin);
517 		if (ncdrop1.ncp)
518 			cache_drop(&ncdrop1);
519 		if (ncdrop2.ncp)
520 			cache_drop(&ncdrop2);
521 		if (vprele1)
522 			vrele(vprele1);
523 		if (vprele2)
524 			vrele(vprele2);
525 	}
526 	return(0);
527 }
528 
529 /*
530  * Unmount a file system.
531  *
532  * Note: unmount takes a path to the vnode mounted on as argument,
533  * not special file (as before).
534  */
535 /*
536  * umount_args(char *path, int flags)
537  */
538 /* ARGSUSED */
539 int
540 sys_unmount(struct unmount_args *uap)
541 {
542 	struct thread *td = curthread;
543 	struct proc *p = td->td_proc;
544 	struct mount *mp = NULL;
545 	int error;
546 	struct nlookupdata nd;
547 
548 	KKASSERT(p);
549 	if (p->p_ucred->cr_prison != NULL)
550 		return (EPERM);
551 	if (usermount == 0 && (error = suser(td)))
552 		return (error);
553 
554 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
555 	if (error == 0)
556 		error = nlookup(&nd);
557 	if (error)
558 		goto out;
559 
560 	mp = nd.nl_nch.mount;
561 
562 	/*
563 	 * Only root, or the user that did the original mount is
564 	 * permitted to unmount this filesystem.
565 	 */
566 	if ((mp->mnt_stat.f_owner != p->p_ucred->cr_uid) &&
567 	    (error = suser(td)))
568 		goto out;
569 
570 	/*
571 	 * Don't allow unmounting the root file system.
572 	 */
573 	if (mp->mnt_flag & MNT_ROOTFS) {
574 		error = EINVAL;
575 		goto out;
576 	}
577 
578 	/*
579 	 * Must be the root of the filesystem
580 	 */
581 	if (nd.nl_nch.ncp != mp->mnt_ncmountpt.ncp) {
582 		error = EINVAL;
583 		goto out;
584 	}
585 
586 out:
587 	nlookup_done(&nd);
588 	if (error)
589 		return (error);
590 	return (dounmount(mp, uap->flags));
591 }
592 
593 /*
594  * Do the actual file system unmount.
595  */
596 static int
597 dounmount_interlock(struct mount *mp)
598 {
599 	if (mp->mnt_kern_flag & MNTK_UNMOUNT)
600 		return (EBUSY);
601 	mp->mnt_kern_flag |= MNTK_UNMOUNT;
602 	return(0);
603 }
604 
605 int
606 dounmount(struct mount *mp, int flags)
607 {
608 	struct namecache *ncp;
609 	struct nchandle nch;
610 	int error;
611 	int async_flag;
612 	int lflags;
613 	int freeok = 1;
614 
615 	/*
616 	 * Exclusive access for unmounting purposes
617 	 */
618 	if ((error = mountlist_interlock(dounmount_interlock, mp)) != 0)
619 		return (error);
620 
621 	/*
622 	 * Allow filesystems to detect that a forced unmount is in progress.
623 	 */
624 	if (flags & MNT_FORCE)
625 		mp->mnt_kern_flag |= MNTK_UNMOUNTF;
626 	lflags = LK_EXCLUSIVE | ((flags & MNT_FORCE) ? 0 : LK_NOWAIT);
627 	error = lockmgr(&mp->mnt_lock, lflags);
628 	if (error) {
629 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
630 		if (mp->mnt_kern_flag & MNTK_MWAIT)
631 			wakeup(mp);
632 		return (error);
633 	}
634 
635 	if (mp->mnt_flag & MNT_EXPUBLIC)
636 		vfs_setpublicfs(NULL, NULL, NULL);
637 
638 	vfs_msync(mp, MNT_WAIT);
639 	async_flag = mp->mnt_flag & MNT_ASYNC;
640 	mp->mnt_flag &=~ MNT_ASYNC;
641 
642 	/*
643 	 * If this filesystem isn't aliasing other filesystems,
644 	 * try to invalidate any remaining namecache entries and
645 	 * check the count afterwords.
646 	 */
647 	if ((mp->mnt_kern_flag & MNTK_NCALIASED) == 0) {
648 		cache_lock(&mp->mnt_ncmountpt);
649 		cache_inval(&mp->mnt_ncmountpt, CINV_DESTROY|CINV_CHILDREN);
650 		cache_unlock(&mp->mnt_ncmountpt);
651 
652 		if ((ncp = mp->mnt_ncmountpt.ncp) != NULL &&
653 		    (ncp->nc_refs != 1 || TAILQ_FIRST(&ncp->nc_list))) {
654 
655 			if ((flags & MNT_FORCE) == 0) {
656 				error = EBUSY;
657 				mount_warning(mp, "Cannot unmount: "
658 						  "%d namecache "
659 						  "references still "
660 						  "present",
661 						  ncp->nc_refs - 1);
662 			} else {
663 				mount_warning(mp, "Forced unmount: "
664 						  "%d namecache "
665 						  "references still "
666 						  "present",
667 						  ncp->nc_refs - 1);
668 				freeok = 0;
669 			}
670 		}
671 	}
672 
673 	/*
674 	 * nchandle records ref the mount structure.  Expect a count of 1
675 	 * (our mount->mnt_ncmountpt).
676 	 */
677 	if (mp->mnt_refs != 1) {
678 		if ((flags & MNT_FORCE) == 0) {
679 			mount_warning(mp, "Cannot unmount: "
680 					  "%d process references still "
681 					  "present", mp->mnt_refs);
682 			error = EBUSY;
683 		} else {
684 			mount_warning(mp, "Forced unmount: "
685 					  "%d process references still "
686 					  "present", mp->mnt_refs);
687 			freeok = 0;
688 		}
689 	}
690 
691 	if (error == 0) {
692 		if (mp->mnt_syncer != NULL)
693 			vrele(mp->mnt_syncer);
694 		if (((mp->mnt_flag & MNT_RDONLY) ||
695 		     (error = VFS_SYNC(mp, MNT_WAIT)) == 0) ||
696 		    (flags & MNT_FORCE)) {
697 			error = VFS_UNMOUNT(mp, flags);
698 		}
699 	}
700 	if (error) {
701 		if (mp->mnt_syncer == NULL)
702 			vfs_allocate_syncvnode(mp);
703 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
704 		mp->mnt_flag |= async_flag;
705 		lockmgr(&mp->mnt_lock, LK_RELEASE);
706 		if (mp->mnt_kern_flag & MNTK_MWAIT)
707 			wakeup(mp);
708 		return (error);
709 	}
710 	/*
711 	 * Clean up any journals still associated with the mount after
712 	 * filesystem activity has ceased.
713 	 */
714 	journal_remove_all_journals(mp,
715 	    ((flags & MNT_FORCE) ? MC_JOURNAL_STOP_IMM : 0));
716 
717 	mountlist_remove(mp);
718 
719 	/*
720 	 * Remove any installed vnode ops here so the individual VFSs don't
721 	 * have to.
722 	 */
723 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
724 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
725 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
726 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
727 	vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
728 
729 	if (mp->mnt_ncmountpt.ncp != NULL) {
730 		nch = mp->mnt_ncmountpt;
731 		cache_zero(&mp->mnt_ncmountpt);
732 		cache_clrmountpt(&nch);
733 		cache_drop(&nch);
734 	}
735 	if (mp->mnt_ncmounton.ncp != NULL) {
736 		nch = mp->mnt_ncmounton;
737 		cache_zero(&mp->mnt_ncmounton);
738 		cache_clrmountpt(&nch);
739 		cache_drop(&nch);
740 	}
741 
742 	mp->mnt_vfc->vfc_refcount--;
743 	if (!TAILQ_EMPTY(&mp->mnt_nvnodelist))
744 		panic("unmount: dangling vnode");
745 	lockmgr(&mp->mnt_lock, LK_RELEASE);
746 	if (mp->mnt_kern_flag & MNTK_MWAIT)
747 		wakeup(mp);
748 	if (freeok)
749 		kfree(mp, M_MOUNT);
750 	return (0);
751 }
752 
753 static
754 void
755 mount_warning(struct mount *mp, const char *ctl, ...)
756 {
757 	char *ptr;
758 	char *buf;
759 	__va_list va;
760 
761 	__va_start(va, ctl);
762 	if (cache_fullpath(NULL, &mp->mnt_ncmounton, &ptr, &buf) == 0) {
763 		kprintf("unmount(%s): ", ptr);
764 		kvprintf(ctl, va);
765 		kprintf("\n");
766 		kfree(buf, M_TEMP);
767 	} else {
768 		kprintf("unmount(%p", mp);
769 		if (mp->mnt_ncmounton.ncp && mp->mnt_ncmounton.ncp->nc_name)
770 			kprintf(",%s", mp->mnt_ncmounton.ncp->nc_name);
771 		kprintf("): ");
772 		kvprintf(ctl, va);
773 		kprintf("\n");
774 	}
775 	__va_end(va);
776 }
777 
778 /*
779  * Shim cache_fullpath() to handle the case where a process is chrooted into
780  * a subdirectory of a mount.  In this case if the root mount matches the
781  * process root directory's mount we have to specify the process's root
782  * directory instead of the mount point, because the mount point might
783  * be above the root directory.
784  */
785 static
786 int
787 mount_path(struct proc *p, struct mount *mp, char **rb, char **fb)
788 {
789 	struct nchandle *nch;
790 
791 	if (p && p->p_fd->fd_nrdir.mount == mp)
792 		nch = &p->p_fd->fd_nrdir;
793 	else
794 		nch = &mp->mnt_ncmountpt;
795 	return(cache_fullpath(p, nch, rb, fb));
796 }
797 
798 /*
799  * Sync each mounted filesystem.
800  */
801 
802 #ifdef DEBUG
803 static int syncprt = 0;
804 SYSCTL_INT(_debug, OID_AUTO, syncprt, CTLFLAG_RW, &syncprt, 0, "");
805 #endif /* DEBUG */
806 
807 static int sync_callback(struct mount *mp, void *data);
808 
809 /* ARGSUSED */
810 int
811 sys_sync(struct sync_args *uap)
812 {
813 	mountlist_scan(sync_callback, NULL, MNTSCAN_FORWARD);
814 #ifdef DEBUG
815 	/*
816 	 * print out buffer pool stat information on each sync() call.
817 	 */
818 	if (syncprt)
819 		vfs_bufstats();
820 #endif /* DEBUG */
821 	return (0);
822 }
823 
824 static
825 int
826 sync_callback(struct mount *mp, void *data __unused)
827 {
828 	int asyncflag;
829 
830 	if ((mp->mnt_flag & MNT_RDONLY) == 0) {
831 		asyncflag = mp->mnt_flag & MNT_ASYNC;
832 		mp->mnt_flag &= ~MNT_ASYNC;
833 		vfs_msync(mp, MNT_NOWAIT);
834 		VFS_SYNC(mp, MNT_NOWAIT);
835 		mp->mnt_flag |= asyncflag;
836 	}
837 	return(0);
838 }
839 
840 /* XXX PRISON: could be per prison flag */
841 static int prison_quotas;
842 #if 0
843 SYSCTL_INT(_kern_prison, OID_AUTO, quotas, CTLFLAG_RW, &prison_quotas, 0, "");
844 #endif
845 
846 /*
847  *  quotactl_args(char *path, int fcmd, int uid, caddr_t arg)
848  *
849  * Change filesystem quotas.
850  */
851 /* ARGSUSED */
852 int
853 sys_quotactl(struct quotactl_args *uap)
854 {
855 	struct nlookupdata nd;
856 	struct thread *td;
857 	struct proc *p;
858 	struct mount *mp;
859 	int error;
860 
861 	td = curthread;
862 	p = td->td_proc;
863 	if (p->p_ucred->cr_prison && !prison_quotas)
864 		return (EPERM);
865 
866 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
867 	if (error == 0)
868 		error = nlookup(&nd);
869 	if (error == 0) {
870 		mp = nd.nl_nch.mount;
871 		error = VFS_QUOTACTL(mp, uap->cmd, uap->uid,
872 				    uap->arg, nd.nl_cred);
873 	}
874 	nlookup_done(&nd);
875 	return (error);
876 }
877 
878 /*
879  * mountctl(char *path, int op, int fd, const void *ctl, int ctllen,
880  *		void *buf, int buflen)
881  *
882  * This function operates on a mount point and executes the specified
883  * operation using the specified control data, and possibly returns data.
884  *
885  * The actual number of bytes stored in the result buffer is returned, 0
886  * if none, otherwise an error is returned.
887  */
888 /* ARGSUSED */
889 int
890 sys_mountctl(struct mountctl_args *uap)
891 {
892 	struct thread *td = curthread;
893 	struct proc *p = td->td_proc;
894 	struct file *fp;
895 	void *ctl = NULL;
896 	void *buf = NULL;
897 	char *path = NULL;
898 	int error;
899 
900 	/*
901 	 * Sanity and permissions checks.  We must be root.
902 	 */
903 	KKASSERT(p);
904 	if (p->p_ucred->cr_prison != NULL)
905 		return (EPERM);
906 	if ((error = suser(td)) != 0)
907 		return (error);
908 
909 	/*
910 	 * Argument length checks
911 	 */
912 	if (uap->ctllen < 0 || uap->ctllen > 1024)
913 		return (EINVAL);
914 	if (uap->buflen < 0 || uap->buflen > 16 * 1024)
915 		return (EINVAL);
916 	if (uap->path == NULL)
917 		return (EINVAL);
918 
919 	/*
920 	 * Allocate the necessary buffers and copyin data
921 	 */
922 	path = objcache_get(namei_oc, M_WAITOK);
923 	error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
924 	if (error)
925 		goto done;
926 
927 	if (uap->ctllen) {
928 		ctl = kmalloc(uap->ctllen + 1, M_TEMP, M_WAITOK|M_ZERO);
929 		error = copyin(uap->ctl, ctl, uap->ctllen);
930 		if (error)
931 			goto done;
932 	}
933 	if (uap->buflen)
934 		buf = kmalloc(uap->buflen + 1, M_TEMP, M_WAITOK|M_ZERO);
935 
936 	/*
937 	 * Validate the descriptor
938 	 */
939 	if (uap->fd >= 0) {
940 		fp = holdfp(p->p_fd, uap->fd, -1);
941 		if (fp == NULL) {
942 			error = EBADF;
943 			goto done;
944 		}
945 	} else {
946 		fp = NULL;
947 	}
948 
949 	/*
950 	 * Execute the internal kernel function and clean up.
951 	 */
952 	error = kern_mountctl(path, uap->op, fp, ctl, uap->ctllen, buf, uap->buflen, &uap->sysmsg_result);
953 	if (fp)
954 		fdrop(fp);
955 	if (error == 0 && uap->sysmsg_result > 0)
956 		error = copyout(buf, uap->buf, uap->sysmsg_result);
957 done:
958 	if (path)
959 		objcache_put(namei_oc, path);
960 	if (ctl)
961 		kfree(ctl, M_TEMP);
962 	if (buf)
963 		kfree(buf, M_TEMP);
964 	return (error);
965 }
966 
967 /*
968  * Execute a mount control operation by resolving the path to a mount point
969  * and calling vop_mountctl().
970  */
971 int
972 kern_mountctl(const char *path, int op, struct file *fp,
973 		const void *ctl, int ctllen,
974 		void *buf, int buflen, int *res)
975 {
976 	struct vnode *vp;
977 	struct mount *mp;
978 	struct nlookupdata nd;
979 	int error;
980 
981 	*res = 0;
982 	vp = NULL;
983 	error = nlookup_init(&nd, path, UIO_SYSSPACE, NLC_FOLLOW);
984 	if (error == 0)
985 		error = nlookup(&nd);
986 	if (error == 0)
987 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
988 	nlookup_done(&nd);
989 	if (error)
990 		return (error);
991 
992 	mp = vp->v_mount;
993 
994 	/*
995 	 * Must be the root of the filesystem
996 	 */
997 	if ((vp->v_flag & VROOT) == 0) {
998 		vput(vp);
999 		return (EINVAL);
1000 	}
1001 	error = vop_mountctl(mp->mnt_vn_use_ops, op, fp, ctl, ctllen,
1002 				buf, buflen, res);
1003 	vput(vp);
1004 	return (error);
1005 }
1006 
1007 int
1008 kern_statfs(struct nlookupdata *nd, struct statfs *buf)
1009 {
1010 	struct thread *td = curthread;
1011 	struct proc *p = td->td_proc;
1012 	struct mount *mp;
1013 	struct statfs *sp;
1014 	char *fullpath, *freepath;
1015 	int error;
1016 
1017 	if ((error = nlookup(nd)) != 0)
1018 		return (error);
1019 	mp = nd->nl_nch.mount;
1020 	sp = &mp->mnt_stat;
1021 	if ((error = VFS_STATFS(mp, sp, nd->nl_cred)) != 0)
1022 		return (error);
1023 
1024 	error = mount_path(p, mp, &fullpath, &freepath);
1025 	if (error)
1026 		return(error);
1027 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1028 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1029 	kfree(freepath, M_TEMP);
1030 
1031 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1032 	bcopy(sp, buf, sizeof(*buf));
1033 	/* Only root should have access to the fsid's. */
1034 	if (suser(td))
1035 		buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
1036 	return (0);
1037 }
1038 
1039 /*
1040  * statfs_args(char *path, struct statfs *buf)
1041  *
1042  * Get filesystem statistics.
1043  */
1044 int
1045 sys_statfs(struct statfs_args *uap)
1046 {
1047 	struct nlookupdata nd;
1048 	struct statfs buf;
1049 	int error;
1050 
1051 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1052 	if (error == 0)
1053 		error = kern_statfs(&nd, &buf);
1054 	nlookup_done(&nd);
1055 	if (error == 0)
1056 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1057 	return (error);
1058 }
1059 
1060 int
1061 kern_fstatfs(int fd, struct statfs *buf)
1062 {
1063 	struct thread *td = curthread;
1064 	struct proc *p = td->td_proc;
1065 	struct file *fp;
1066 	struct mount *mp;
1067 	struct statfs *sp;
1068 	char *fullpath, *freepath;
1069 	int error;
1070 
1071 	KKASSERT(p);
1072 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
1073 		return (error);
1074 	mp = ((struct vnode *)fp->f_data)->v_mount;
1075 	if (mp == NULL) {
1076 		error = EBADF;
1077 		goto done;
1078 	}
1079 	if (fp->f_cred == NULL) {
1080 		error = EINVAL;
1081 		goto done;
1082 	}
1083 	sp = &mp->mnt_stat;
1084 	if ((error = VFS_STATFS(mp, sp, fp->f_cred)) != 0)
1085 		goto done;
1086 
1087 	if ((error = mount_path(p, mp, &fullpath, &freepath)) != 0)
1088 		goto done;
1089 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1090 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1091 	kfree(freepath, M_TEMP);
1092 
1093 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1094 	bcopy(sp, buf, sizeof(*buf));
1095 
1096 	/* Only root should have access to the fsid's. */
1097 	if (suser(td))
1098 		buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
1099 	error = 0;
1100 done:
1101 	fdrop(fp);
1102 	return (error);
1103 }
1104 
1105 /*
1106  * fstatfs_args(int fd, struct statfs *buf)
1107  *
1108  * Get filesystem statistics.
1109  */
1110 int
1111 sys_fstatfs(struct fstatfs_args *uap)
1112 {
1113 	struct statfs buf;
1114 	int error;
1115 
1116 	error = kern_fstatfs(uap->fd, &buf);
1117 
1118 	if (error == 0)
1119 		error = copyout(&buf, uap->buf, sizeof(*uap->buf));
1120 	return (error);
1121 }
1122 
1123 /*
1124  * getfsstat_args(struct statfs *buf, long bufsize, int flags)
1125  *
1126  * Get statistics on all filesystems.
1127  */
1128 
1129 struct getfsstat_info {
1130 	struct statfs *sfsp;
1131 	long count;
1132 	long maxcount;
1133 	int error;
1134 	int flags;
1135 	struct proc *p;
1136 };
1137 
1138 static int getfsstat_callback(struct mount *, void *);
1139 
1140 /* ARGSUSED */
1141 int
1142 sys_getfsstat(struct getfsstat_args *uap)
1143 {
1144 	struct thread *td = curthread;
1145 	struct proc *p = td->td_proc;
1146 	struct getfsstat_info info;
1147 
1148 	bzero(&info, sizeof(info));
1149 
1150 	info.maxcount = uap->bufsize / sizeof(struct statfs);
1151 	info.sfsp = uap->buf;
1152 	info.count = 0;
1153 	info.flags = uap->flags;
1154 	info.p = p;
1155 
1156 	mountlist_scan(getfsstat_callback, &info, MNTSCAN_FORWARD);
1157 	if (info.sfsp && info.count > info.maxcount)
1158 		uap->sysmsg_result = info.maxcount;
1159 	else
1160 		uap->sysmsg_result = info.count;
1161 	return (info.error);
1162 }
1163 
1164 static int
1165 getfsstat_callback(struct mount *mp, void *data)
1166 {
1167 	struct getfsstat_info *info = data;
1168 	struct statfs *sp;
1169 	char *freepath;
1170 	char *fullpath;
1171 	int error;
1172 
1173 	if (info->sfsp && info->count < info->maxcount) {
1174 		if (info->p && !chroot_visible_mnt(mp, info->p))
1175 			return(0);
1176 		sp = &mp->mnt_stat;
1177 
1178 		/*
1179 		 * If MNT_NOWAIT or MNT_LAZY is specified, do not
1180 		 * refresh the fsstat cache. MNT_NOWAIT or MNT_LAZY
1181 		 * overrides MNT_WAIT.
1182 		 */
1183 		if (((info->flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
1184 		    (info->flags & MNT_WAIT)) &&
1185 		    (error = VFS_STATFS(mp, sp, info->p->p_ucred))) {
1186 			return(0);
1187 		}
1188 		sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
1189 
1190 		error = mount_path(info->p, mp, &fullpath, &freepath);
1191 		if (error) {
1192 			info->error = error;
1193 			return(-1);
1194 		}
1195 		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
1196 		strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
1197 		kfree(freepath, M_TEMP);
1198 
1199 		error = copyout(sp, info->sfsp, sizeof(*sp));
1200 		if (error) {
1201 			info->error = error;
1202 			return (-1);
1203 		}
1204 		++info->sfsp;
1205 	}
1206 	info->count++;
1207 	return(0);
1208 }
1209 
1210 /*
1211  * fchdir_args(int fd)
1212  *
1213  * Change current working directory to a given file descriptor.
1214  */
1215 /* ARGSUSED */
1216 int
1217 sys_fchdir(struct fchdir_args *uap)
1218 {
1219 	struct thread *td = curthread;
1220 	struct proc *p = td->td_proc;
1221 	struct filedesc *fdp = p->p_fd;
1222 	struct vnode *vp, *ovp;
1223 	struct mount *mp;
1224 	struct file *fp;
1225 	struct nchandle nch, onch, tnch;
1226 	int error;
1227 
1228 	if ((error = holdvnode(fdp, uap->fd, &fp)) != 0)
1229 		return (error);
1230 	vp = (struct vnode *)fp->f_data;
1231 	vref(vp);
1232 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1233 	if (vp->v_type != VDIR || fp->f_nchandle.ncp == NULL)
1234 		error = ENOTDIR;
1235 	else
1236 		error = VOP_ACCESS(vp, VEXEC, p->p_ucred);
1237 	if (error) {
1238 		vput(vp);
1239 		fdrop(fp);
1240 		return (error);
1241 	}
1242 	cache_copy(&fp->f_nchandle, &nch);
1243 
1244 	/*
1245 	 * If the ncp has become a mount point, traverse through
1246 	 * the mount point.
1247 	 */
1248 
1249 	while (!error && (nch.ncp->nc_flag & NCF_ISMOUNTPT) &&
1250 	       (mp = cache_findmount(&nch)) != NULL
1251 	) {
1252 		error = nlookup_mp(mp, &tnch);
1253 		if (error == 0) {
1254 			cache_unlock(&tnch);	/* leave ref intact */
1255 			vput(vp);
1256 			vp = tnch.ncp->nc_vp;
1257 			error = vget(vp, LK_SHARED);
1258 			KKASSERT(error == 0);
1259 			cache_drop(&nch);
1260 			nch = tnch;
1261 		}
1262 	}
1263 	if (error == 0) {
1264 		ovp = fdp->fd_cdir;
1265 		onch = fdp->fd_ncdir;
1266 		vn_unlock(vp);		/* leave ref intact */
1267 		fdp->fd_cdir = vp;
1268 		fdp->fd_ncdir = nch;
1269 		cache_drop(&onch);
1270 		vrele(ovp);
1271 	} else {
1272 		cache_drop(&nch);
1273 		vput(vp);
1274 	}
1275 	fdrop(fp);
1276 	return (error);
1277 }
1278 
1279 int
1280 kern_chdir(struct nlookupdata *nd)
1281 {
1282 	struct thread *td = curthread;
1283 	struct proc *p = td->td_proc;
1284 	struct filedesc *fdp = p->p_fd;
1285 	struct vnode *vp, *ovp;
1286 	struct nchandle onch;
1287 	int error;
1288 
1289 	if ((error = nlookup(nd)) != 0)
1290 		return (error);
1291 	if ((vp = nd->nl_nch.ncp->nc_vp) == NULL)
1292 		return (ENOENT);
1293 	if ((error = vget(vp, LK_SHARED)) != 0)
1294 		return (error);
1295 
1296 	error = checkvp_chdir(vp, td);
1297 	vn_unlock(vp);
1298 	if (error == 0) {
1299 		ovp = fdp->fd_cdir;
1300 		onch = fdp->fd_ncdir;
1301 		cache_unlock(&nd->nl_nch);	/* leave reference intact */
1302 		fdp->fd_ncdir = nd->nl_nch;
1303 		fdp->fd_cdir = vp;
1304 		cache_drop(&onch);
1305 		vrele(ovp);
1306 		cache_zero(&nd->nl_nch);
1307 	} else {
1308 		vrele(vp);
1309 	}
1310 	return (error);
1311 }
1312 
1313 /*
1314  * chdir_args(char *path)
1315  *
1316  * Change current working directory (``.'').
1317  */
1318 int
1319 sys_chdir(struct chdir_args *uap)
1320 {
1321 	struct nlookupdata nd;
1322 	int error;
1323 
1324 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1325 	if (error == 0)
1326 		error = kern_chdir(&nd);
1327 	nlookup_done(&nd);
1328 	return (error);
1329 }
1330 
1331 /*
1332  * Helper function for raised chroot(2) security function:  Refuse if
1333  * any filedescriptors are open directories.
1334  */
1335 static int
1336 chroot_refuse_vdir_fds(struct filedesc *fdp)
1337 {
1338 	struct vnode *vp;
1339 	struct file *fp;
1340 	int error;
1341 	int fd;
1342 
1343 	for (fd = 0; fd < fdp->fd_nfiles ; fd++) {
1344 		if ((error = holdvnode(fdp, fd, &fp)) != 0)
1345 			continue;
1346 		vp = (struct vnode *)fp->f_data;
1347 		if (vp->v_type != VDIR) {
1348 			fdrop(fp);
1349 			continue;
1350 		}
1351 		fdrop(fp);
1352 		return(EPERM);
1353 	}
1354 	return (0);
1355 }
1356 
1357 /*
1358  * This sysctl determines if we will allow a process to chroot(2) if it
1359  * has a directory open:
1360  *	0: disallowed for all processes.
1361  *	1: allowed for processes that were not already chroot(2)'ed.
1362  *	2: allowed for all processes.
1363  */
1364 
1365 static int chroot_allow_open_directories = 1;
1366 
1367 SYSCTL_INT(_kern, OID_AUTO, chroot_allow_open_directories, CTLFLAG_RW,
1368      &chroot_allow_open_directories, 0, "");
1369 
1370 /*
1371  * chroot to the specified namecache entry.  We obtain the vp from the
1372  * namecache data.  The passed ncp must be locked and referenced and will
1373  * remain locked and referenced on return.
1374  */
1375 int
1376 kern_chroot(struct nchandle *nch)
1377 {
1378 	struct thread *td = curthread;
1379 	struct proc *p = td->td_proc;
1380 	struct filedesc *fdp = p->p_fd;
1381 	struct vnode *vp;
1382 	int error;
1383 
1384 	/*
1385 	 * Only root can chroot
1386 	 */
1387 	if ((error = suser_cred(p->p_ucred, PRISON_ROOT)) != 0)
1388 		return (error);
1389 
1390 	/*
1391 	 * Disallow open directory descriptors (fchdir() breakouts).
1392 	 */
1393 	if (chroot_allow_open_directories == 0 ||
1394 	   (chroot_allow_open_directories == 1 && fdp->fd_rdir != rootvnode)) {
1395 		if ((error = chroot_refuse_vdir_fds(fdp)) != 0)
1396 			return (error);
1397 	}
1398 	if ((vp = nch->ncp->nc_vp) == NULL)
1399 		return (ENOENT);
1400 
1401 	if ((error = vget(vp, LK_SHARED)) != 0)
1402 		return (error);
1403 
1404 	/*
1405 	 * Check the validity of vp as a directory to change to and
1406 	 * associate it with rdir/jdir.
1407 	 */
1408 	error = checkvp_chdir(vp, td);
1409 	vn_unlock(vp);			/* leave reference intact */
1410 	if (error == 0) {
1411 		vrele(fdp->fd_rdir);
1412 		fdp->fd_rdir = vp;	/* reference inherited by fd_rdir */
1413 		cache_drop(&fdp->fd_nrdir);
1414 		cache_copy(nch, &fdp->fd_nrdir);
1415 		if (fdp->fd_jdir == NULL) {
1416 			fdp->fd_jdir = vp;
1417 			vref(fdp->fd_jdir);
1418 			cache_copy(nch, &fdp->fd_njdir);
1419 		}
1420 	} else {
1421 		vrele(vp);
1422 	}
1423 	return (error);
1424 }
1425 
1426 /*
1427  * chroot_args(char *path)
1428  *
1429  * Change notion of root (``/'') directory.
1430  */
1431 /* ARGSUSED */
1432 int
1433 sys_chroot(struct chroot_args *uap)
1434 {
1435 	struct thread *td = curthread;
1436 	struct nlookupdata nd;
1437 	int error;
1438 
1439 	KKASSERT(td->td_proc);
1440 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1441 	if (error) {
1442 		nlookup_done(&nd);
1443 		return(error);
1444 	}
1445 	error = nlookup(&nd);
1446 	if (error == 0)
1447 		error = kern_chroot(&nd.nl_nch);
1448 	nlookup_done(&nd);
1449 	return(error);
1450 }
1451 
1452 /*
1453  * Common routine for chroot and chdir.  Given a locked, referenced vnode,
1454  * determine whether it is legal to chdir to the vnode.  The vnode's state
1455  * is not changed by this call.
1456  */
1457 int
1458 checkvp_chdir(struct vnode *vp, struct thread *td)
1459 {
1460 	int error;
1461 
1462 	if (vp->v_type != VDIR)
1463 		error = ENOTDIR;
1464 	else
1465 		error = VOP_ACCESS(vp, VEXEC, td->td_proc->p_ucred);
1466 	return (error);
1467 }
1468 
1469 int
1470 kern_open(struct nlookupdata *nd, int oflags, int mode, int *res)
1471 {
1472 	struct thread *td = curthread;
1473 	struct proc *p = td->td_proc;
1474 	struct lwp *lp = td->td_lwp;
1475 	struct filedesc *fdp = p->p_fd;
1476 	int cmode, flags;
1477 	struct file *nfp;
1478 	struct file *fp;
1479 	struct vnode *vp;
1480 	int type, indx, error;
1481 	struct flock lf;
1482 
1483 	if ((oflags & O_ACCMODE) == O_ACCMODE)
1484 		return (EINVAL);
1485 	flags = FFLAGS(oflags);
1486 	error = falloc(p, &nfp, NULL);
1487 	if (error)
1488 		return (error);
1489 	fp = nfp;
1490 	cmode = ((mode &~ fdp->fd_cmask) & ALLPERMS) &~ S_ISTXT;
1491 
1492 	/*
1493 	 * XXX p_dupfd is a real mess.  It allows a device to return a
1494 	 * file descriptor to be duplicated rather then doing the open
1495 	 * itself.
1496 	 */
1497 	lp->lwp_dupfd = -1;
1498 
1499 	/*
1500 	 * Call vn_open() to do the lookup and assign the vnode to the
1501 	 * file pointer.  vn_open() does not change the ref count on fp
1502 	 * and the vnode, on success, will be inherited by the file pointer
1503 	 * and unlocked.
1504 	 */
1505 	nd->nl_flags |= NLC_LOCKVP;
1506 	error = vn_open(nd, fp, flags, cmode);
1507 	nlookup_done(nd);
1508 	if (error) {
1509 		/*
1510 		 * handle special fdopen() case.  bleh.  dupfdopen() is
1511 		 * responsible for dropping the old contents of ofiles[indx]
1512 		 * if it succeeds.
1513 		 *
1514 		 * Note that fsetfd() will add a ref to fp which represents
1515 		 * the fd_files[] assignment.  We must still drop our
1516 		 * reference.
1517 		 */
1518 		if ((error == ENODEV || error == ENXIO) && lp->lwp_dupfd >= 0) {
1519 			if (fdalloc(p, 0, &indx) == 0) {
1520 				error = dupfdopen(p, indx, lp->lwp_dupfd, flags, error);
1521 				if (error == 0) {
1522 					*res = indx;
1523 					fdrop(fp);	/* our ref */
1524 					return (0);
1525 				}
1526 				fsetfd(p, NULL, indx);
1527 			}
1528 		}
1529 		fdrop(fp);	/* our ref */
1530 		if (error == ERESTART)
1531 			error = EINTR;
1532 		return (error);
1533 	}
1534 
1535 	/*
1536 	 * ref the vnode for ourselves so it can't be ripped out from under
1537 	 * is.  XXX need an ND flag to request that the vnode be returned
1538 	 * anyway.
1539 	 *
1540 	 * Reserve a file descriptor but do not assign it until the open
1541 	 * succeeds.
1542 	 */
1543 	vp = (struct vnode *)fp->f_data;
1544 	vref(vp);
1545 	if ((error = fdalloc(p, 0, &indx)) != 0) {
1546 		fdrop(fp);
1547 		vrele(vp);
1548 		return (error);
1549 	}
1550 
1551 	/*
1552 	 * If no error occurs the vp will have been assigned to the file
1553 	 * pointer.
1554 	 */
1555 	lp->lwp_dupfd = 0;
1556 
1557 	if (flags & (O_EXLOCK | O_SHLOCK)) {
1558 		lf.l_whence = SEEK_SET;
1559 		lf.l_start = 0;
1560 		lf.l_len = 0;
1561 		if (flags & O_EXLOCK)
1562 			lf.l_type = F_WRLCK;
1563 		else
1564 			lf.l_type = F_RDLCK;
1565 		if (flags & FNONBLOCK)
1566 			type = 0;
1567 		else
1568 			type = F_WAIT;
1569 
1570 		if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0) {
1571 			/*
1572 			 * lock request failed.  Clean up the reserved
1573 			 * descriptor.
1574 			 */
1575 			vrele(vp);
1576 			fsetfd(p, NULL, indx);
1577 			fdrop(fp);
1578 			return (error);
1579 		}
1580 		fp->f_flag |= FHASLOCK;
1581 	}
1582 #if 0
1583 	/*
1584 	 * Assert that all regular file vnodes were created with a object.
1585 	 */
1586 	KASSERT(vp->v_type != VREG || vp->v_object != NULL,
1587 		("open: regular file has no backing object after vn_open"));
1588 #endif
1589 
1590 	vrele(vp);
1591 
1592 	/*
1593 	 * release our private reference, leaving the one associated with the
1594 	 * descriptor table intact.
1595 	 */
1596 	fsetfd(p, fp, indx);
1597 	fdrop(fp);
1598 	*res = indx;
1599 	return (0);
1600 }
1601 
1602 /*
1603  * open_args(char *path, int flags, int mode)
1604  *
1605  * Check permissions, allocate an open file structure,
1606  * and call the device open routine if any.
1607  */
1608 int
1609 sys_open(struct open_args *uap)
1610 {
1611 	struct nlookupdata nd;
1612 	int error;
1613 
1614 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1615 	if (error == 0) {
1616 		error = kern_open(&nd, uap->flags,
1617 				    uap->mode, &uap->sysmsg_result);
1618 	}
1619 	nlookup_done(&nd);
1620 	return (error);
1621 }
1622 
1623 int
1624 kern_mknod(struct nlookupdata *nd, int mode, int rmajor, int rminor)
1625 {
1626 	struct thread *td = curthread;
1627 	struct proc *p = td->td_proc;
1628 	struct vnode *vp;
1629 	struct vnode *dvp;
1630 	struct vattr vattr;
1631 	int error;
1632 	int whiteout = 0;
1633 
1634 	KKASSERT(p);
1635 
1636 	switch (mode & S_IFMT) {
1637 	case S_IFCHR:
1638 	case S_IFBLK:
1639 		error = suser(td);
1640 		break;
1641 	default:
1642 		error = suser_cred(p->p_ucred, PRISON_ROOT);
1643 		break;
1644 	}
1645 	if (error)
1646 		return (error);
1647 
1648 	bwillwrite();
1649 	nd->nl_flags |= NLC_CREATE;
1650 	if ((error = nlookup(nd)) != 0)
1651 		return (error);
1652 	if (nd->nl_nch.ncp->nc_vp)
1653 		return (EEXIST);
1654 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
1655 		return (error);
1656 	if ((dvp = nd->nl_nch.ncp->nc_parent->nc_vp) == NULL)
1657 		return (EPERM);
1658 	/* vhold(dvp); - DVP can't go away */
1659 
1660 	VATTR_NULL(&vattr);
1661 	vattr.va_mode = (mode & ALLPERMS) &~ p->p_fd->fd_cmask;
1662 	vattr.va_rmajor = rmajor;
1663 	vattr.va_rminor = rminor;
1664 	whiteout = 0;
1665 
1666 	switch (mode & S_IFMT) {
1667 	case S_IFMT:	/* used by badsect to flag bad sectors */
1668 		vattr.va_type = VBAD;
1669 		break;
1670 	case S_IFCHR:
1671 		vattr.va_type = VCHR;
1672 		break;
1673 	case S_IFBLK:
1674 		vattr.va_type = VBLK;
1675 		break;
1676 	case S_IFWHT:
1677 		whiteout = 1;
1678 		break;
1679 	default:
1680 		error = EINVAL;
1681 		break;
1682 	}
1683 	if (error == 0) {
1684 		if (whiteout) {
1685 			error = VOP_NWHITEOUT(&nd->nl_nch, dvp, nd->nl_cred, NAMEI_CREATE);
1686 		} else {
1687 			vp = NULL;
1688 			error = VOP_NMKNOD(&nd->nl_nch, dvp, &vp, nd->nl_cred, &vattr);
1689 			if (error == 0)
1690 				vput(vp);
1691 		}
1692 	}
1693 	/* vdrop(dvp); */
1694 	return (error);
1695 }
1696 
1697 /*
1698  * mknod_args(char *path, int mode, int dev)
1699  *
1700  * Create a special file.
1701  */
1702 int
1703 sys_mknod(struct mknod_args *uap)
1704 {
1705 	struct nlookupdata nd;
1706 	int error;
1707 
1708 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
1709 	if (error == 0) {
1710 		error = kern_mknod(&nd, uap->mode,
1711 				   umajor(uap->dev), uminor(uap->dev));
1712 	}
1713 	nlookup_done(&nd);
1714 	return (error);
1715 }
1716 
1717 int
1718 kern_mkfifo(struct nlookupdata *nd, int mode)
1719 {
1720 	struct thread *td = curthread;
1721 	struct proc *p = td->td_proc;
1722 	struct vattr vattr;
1723 	struct vnode *vp;
1724 	struct vnode *dvp;
1725 	int error;
1726 
1727 	bwillwrite();
1728 
1729 	nd->nl_flags |= NLC_CREATE;
1730 	if ((error = nlookup(nd)) != 0)
1731 		return (error);
1732 	if (nd->nl_nch.ncp->nc_vp)
1733 		return (EEXIST);
1734 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
1735 		return (error);
1736 	if ((dvp = nd->nl_nch.ncp->nc_parent->nc_vp) == NULL)
1737 		return (EPERM);
1738 	/* vhold(dvp); - DVP can't go away */
1739 
1740 	VATTR_NULL(&vattr);
1741 	vattr.va_type = VFIFO;
1742 	vattr.va_mode = (mode & ALLPERMS) &~ p->p_fd->fd_cmask;
1743 	vp = NULL;
1744 	error = VOP_NMKNOD(&nd->nl_nch, dvp, &vp, nd->nl_cred, &vattr);
1745 	/* vdrop(dvp); */
1746 	if (error == 0)
1747 		vput(vp);
1748 	return (error);
1749 }
1750 
1751 /*
1752  * mkfifo_args(char *path, int mode)
1753  *
1754  * Create a named pipe.
1755  */
1756 int
1757 sys_mkfifo(struct mkfifo_args *uap)
1758 {
1759 	struct nlookupdata nd;
1760 	int error;
1761 
1762 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
1763 	if (error == 0)
1764 		error = kern_mkfifo(&nd, uap->mode);
1765 	nlookup_done(&nd);
1766 	return (error);
1767 }
1768 
1769 static int hardlink_check_uid = 0;
1770 SYSCTL_INT(_kern, OID_AUTO, hardlink_check_uid, CTLFLAG_RW,
1771     &hardlink_check_uid, 0,
1772     "Unprivileged processes cannot create hard links to files owned by other "
1773     "users");
1774 static int hardlink_check_gid = 0;
1775 SYSCTL_INT(_kern, OID_AUTO, hardlink_check_gid, CTLFLAG_RW,
1776     &hardlink_check_gid, 0,
1777     "Unprivileged processes cannot create hard links to files owned by other "
1778     "groups");
1779 
1780 static int
1781 can_hardlink(struct vnode *vp, struct thread *td, struct ucred *cred)
1782 {
1783 	struct vattr va;
1784 	int error;
1785 
1786 	/*
1787 	 * Shortcut if disabled
1788 	 */
1789 	if (hardlink_check_uid == 0 && hardlink_check_gid == 0)
1790 		return (0);
1791 
1792 	/*
1793 	 * root cred can always hardlink
1794 	 */
1795 	if (suser_cred(cred, PRISON_ROOT) == 0)
1796 		return (0);
1797 
1798 	/*
1799 	 * Otherwise only if the originating file is owned by the
1800 	 * same user or group.  Note that any group is allowed if
1801 	 * the file is owned by the caller.
1802 	 */
1803 	error = VOP_GETATTR(vp, &va);
1804 	if (error != 0)
1805 		return (error);
1806 
1807 	if (hardlink_check_uid) {
1808 		if (cred->cr_uid != va.va_uid)
1809 			return (EPERM);
1810 	}
1811 
1812 	if (hardlink_check_gid) {
1813 		if (cred->cr_uid != va.va_uid && !groupmember(va.va_gid, cred))
1814 			return (EPERM);
1815 	}
1816 
1817 	return (0);
1818 }
1819 
1820 int
1821 kern_link(struct nlookupdata *nd, struct nlookupdata *linknd)
1822 {
1823 	struct thread *td = curthread;
1824 	struct vnode *vp;
1825 	struct vnode *dvp;
1826 	int error;
1827 
1828 	/*
1829 	 * Lookup the source and obtained a locked vnode.
1830 	 *
1831 	 * XXX relookup on vget failure / race ?
1832 	 */
1833 	bwillwrite();
1834 	if ((error = nlookup(nd)) != 0)
1835 		return (error);
1836 	vp = nd->nl_nch.ncp->nc_vp;
1837 	KKASSERT(vp != NULL);
1838 	if (vp->v_type == VDIR)
1839 		return (EPERM);		/* POSIX */
1840 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
1841 		return (error);
1842 	if ((error = vget(vp, LK_EXCLUSIVE)) != 0)
1843 		return (error);
1844 
1845 	/*
1846 	 * Unlock the source so we can lookup the target without deadlocking
1847 	 * (XXX vp is locked already, possible other deadlock?).  The target
1848 	 * must not exist.
1849 	 */
1850 	KKASSERT(nd->nl_flags & NLC_NCPISLOCKED);
1851 	nd->nl_flags &= ~NLC_NCPISLOCKED;
1852 	cache_unlock(&nd->nl_nch);
1853 
1854 	linknd->nl_flags |= NLC_CREATE;
1855 	if ((error = nlookup(linknd)) != 0) {
1856 		vput(vp);
1857 		return (error);
1858 	}
1859 	if (linknd->nl_nch.ncp->nc_vp) {
1860 		vput(vp);
1861 		return (EEXIST);
1862 	}
1863 	if ((dvp = linknd->nl_nch.ncp->nc_parent->nc_vp) == NULL) {
1864 		vput(vp);
1865 		return (EPERM);
1866 	}
1867 	/* vhold(dvp); - dvp can't go away */
1868 
1869 	/*
1870 	 * Finally run the new API VOP.
1871 	 */
1872 	error = can_hardlink(vp, td, td->td_proc->p_ucred);
1873 	if (error == 0)
1874 		error = VOP_NLINK(&linknd->nl_nch, dvp, vp, linknd->nl_cred);
1875 	/* vdrop(dvp); */
1876 	vput(vp);
1877 	return (error);
1878 }
1879 
1880 /*
1881  * link_args(char *path, char *link)
1882  *
1883  * Make a hard file link.
1884  */
1885 int
1886 sys_link(struct link_args *uap)
1887 {
1888 	struct nlookupdata nd, linknd;
1889 	int error;
1890 
1891 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
1892 	if (error == 0) {
1893 		error = nlookup_init(&linknd, uap->link, UIO_USERSPACE, 0);
1894 		if (error == 0)
1895 			error = kern_link(&nd, &linknd);
1896 		nlookup_done(&linknd);
1897 	}
1898 	nlookup_done(&nd);
1899 	return (error);
1900 }
1901 
1902 int
1903 kern_symlink(struct nlookupdata *nd, char *path, int mode)
1904 {
1905 	struct vattr vattr;
1906 	struct vnode *vp;
1907 	struct vnode *dvp;
1908 	int error;
1909 
1910 	bwillwrite();
1911 	nd->nl_flags |= NLC_CREATE;
1912 	if ((error = nlookup(nd)) != 0)
1913 		return (error);
1914 	if (nd->nl_nch.ncp->nc_vp)
1915 		return (EEXIST);
1916 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
1917 		return (error);
1918 	if ((dvp = nd->nl_nch.ncp->nc_parent->nc_vp) == NULL)
1919 		return (EPERM);
1920 	/* vhold(dvp); - dvp can't go away */
1921 	VATTR_NULL(&vattr);
1922 	vattr.va_mode = mode;
1923 	error = VOP_NSYMLINK(&nd->nl_nch, dvp, &vp, nd->nl_cred, &vattr, path);
1924 	/* vdrop(dvp); */
1925 	if (error == 0)
1926 		vput(vp);
1927 	return (error);
1928 }
1929 
1930 /*
1931  * symlink(char *path, char *link)
1932  *
1933  * Make a symbolic link.
1934  */
1935 int
1936 sys_symlink(struct symlink_args *uap)
1937 {
1938 	struct thread *td = curthread;
1939 	struct nlookupdata nd;
1940 	char *path;
1941 	int error;
1942 	int mode;
1943 
1944 	path = objcache_get(namei_oc, M_WAITOK);
1945 	error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
1946 	if (error == 0) {
1947 		error = nlookup_init(&nd, uap->link, UIO_USERSPACE, 0);
1948 		if (error == 0) {
1949 			mode = ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask;
1950 			error = kern_symlink(&nd, path, mode);
1951 		}
1952 		nlookup_done(&nd);
1953 	}
1954 	objcache_put(namei_oc, path);
1955 	return (error);
1956 }
1957 
1958 /*
1959  * undelete_args(char *path)
1960  *
1961  * Delete a whiteout from the filesystem.
1962  */
1963 /* ARGSUSED */
1964 int
1965 sys_undelete(struct undelete_args *uap)
1966 {
1967 	struct nlookupdata nd;
1968 	struct vnode *dvp;
1969 	int error;
1970 
1971 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
1972 	bwillwrite();
1973 	nd.nl_flags |= NLC_DELETE;
1974 	if (error == 0)
1975 		error = nlookup(&nd);
1976 	if (error == 0)
1977 		error = ncp_writechk(&nd.nl_nch);
1978 	dvp = NULL;
1979 	if (error == 0) {
1980 		if ((dvp = nd.nl_nch.ncp->nc_parent->nc_vp) == NULL)
1981 			error = EPERM;
1982 	}
1983 	if (error == 0) {
1984 		/* vhold(dvp); - dvp can't go away */
1985 		error = VOP_NWHITEOUT(&nd.nl_nch, dvp, nd.nl_cred, NAMEI_DELETE);
1986 		/* vdrop(dvp); */
1987 	}
1988 	nlookup_done(&nd);
1989 	return (error);
1990 }
1991 
1992 int
1993 kern_unlink(struct nlookupdata *nd)
1994 {
1995 	struct vnode *dvp;
1996 	int error;
1997 
1998 	bwillwrite();
1999 	nd->nl_flags |= NLC_DELETE;
2000 	if ((error = nlookup(nd)) != 0)
2001 		return (error);
2002 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2003 		return (error);
2004 	if ((dvp = nd->nl_nch.ncp->nc_parent->nc_vp) == NULL)
2005 		return (EPERM);
2006 	/* vhold(dvp); - dvp can't go away */
2007 	error = VOP_NREMOVE(&nd->nl_nch, dvp, nd->nl_cred);
2008 	/* vdrop(dvp); */
2009 	return (error);
2010 }
2011 
2012 /*
2013  * unlink_args(char *path)
2014  *
2015  * Delete a name from the filesystem.
2016  */
2017 int
2018 sys_unlink(struct unlink_args *uap)
2019 {
2020 	struct nlookupdata nd;
2021 	int error;
2022 
2023 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2024 	if (error == 0)
2025 		error = kern_unlink(&nd);
2026 	nlookup_done(&nd);
2027 	return (error);
2028 }
2029 
2030 int
2031 kern_lseek(int fd, off_t offset, int whence, off_t *res)
2032 {
2033 	struct thread *td = curthread;
2034 	struct proc *p = td->td_proc;
2035 	struct file *fp;
2036 	struct vattr vattr;
2037 	int error;
2038 
2039 	fp = holdfp(p->p_fd, fd, -1);
2040 	if (fp == NULL)
2041 		return (EBADF);
2042 	if (fp->f_type != DTYPE_VNODE) {
2043 		error = ESPIPE;
2044 		goto done;
2045 	}
2046 
2047 	switch (whence) {
2048 	case L_INCR:
2049 		fp->f_offset += offset;
2050 		error = 0;
2051 		break;
2052 	case L_XTND:
2053 		error = VOP_GETATTR((struct vnode *)fp->f_data, &vattr);
2054 		if (error == 0)
2055 			fp->f_offset = offset + vattr.va_size;
2056 		break;
2057 	case L_SET:
2058 		fp->f_offset = offset;
2059 		error = 0;
2060 		break;
2061 	default:
2062 		error = EINVAL;
2063 		break;
2064 	}
2065 	*res = fp->f_offset;
2066 done:
2067 	fdrop(fp);
2068 	return (error);
2069 }
2070 
2071 /*
2072  * lseek_args(int fd, int pad, off_t offset, int whence)
2073  *
2074  * Reposition read/write file offset.
2075  */
2076 int
2077 sys_lseek(struct lseek_args *uap)
2078 {
2079 	int error;
2080 
2081 	error = kern_lseek(uap->fd, uap->offset, uap->whence,
2082 	    &uap->sysmsg_offset);
2083 
2084 	return (error);
2085 }
2086 
2087 int
2088 kern_access(struct nlookupdata *nd, int aflags)
2089 {
2090 	struct vnode *vp;
2091 	int error, flags;
2092 
2093 	if ((error = nlookup(nd)) != 0)
2094 		return (error);
2095 retry:
2096 	error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_EXCLUSIVE, &vp);
2097 	if (error)
2098 		return (error);
2099 
2100 	/* Flags == 0 means only check for existence. */
2101 	if (aflags) {
2102 		flags = 0;
2103 		if (aflags & R_OK)
2104 			flags |= VREAD;
2105 		if (aflags & W_OK)
2106 			flags |= VWRITE;
2107 		if (aflags & X_OK)
2108 			flags |= VEXEC;
2109 		if ((flags & VWRITE) == 0 ||
2110 		    (error = vn_writechk(vp, &nd->nl_nch)) == 0)
2111 			error = VOP_ACCESS(vp, flags, nd->nl_cred);
2112 
2113 		/*
2114 		 * If the file handle is stale we have to re-resolve the
2115 		 * entry.  This is a hack at the moment.
2116 		 */
2117 		if (error == ESTALE) {
2118 			vput(vp);
2119 			cache_setunresolved(&nd->nl_nch);
2120 			error = cache_resolve(&nd->nl_nch, nd->nl_cred);
2121 			if (error == 0) {
2122 				vp = NULL;
2123 				goto retry;
2124 			}
2125 			return(error);
2126 		}
2127 	}
2128 	vput(vp);
2129 	return (error);
2130 }
2131 
2132 /*
2133  * access_args(char *path, int flags)
2134  *
2135  * Check access permissions.
2136  */
2137 int
2138 sys_access(struct access_args *uap)
2139 {
2140 	struct nlookupdata nd;
2141 	int error;
2142 
2143 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2144 	if (error == 0)
2145 		error = kern_access(&nd, uap->flags);
2146 	nlookup_done(&nd);
2147 	return (error);
2148 }
2149 
2150 int
2151 kern_stat(struct nlookupdata *nd, struct stat *st)
2152 {
2153 	int error;
2154 	struct vnode *vp;
2155 	thread_t td;
2156 
2157 	if ((error = nlookup(nd)) != 0)
2158 		return (error);
2159 again:
2160 	if ((vp = nd->nl_nch.ncp->nc_vp) == NULL)
2161 		return (ENOENT);
2162 
2163 	td = curthread;
2164 	if ((error = vget(vp, LK_SHARED)) != 0)
2165 		return (error);
2166 	error = vn_stat(vp, st, nd->nl_cred);
2167 
2168 	/*
2169 	 * If the file handle is stale we have to re-resolve the entry.  This
2170 	 * is a hack at the moment.
2171 	 */
2172 	if (error == ESTALE) {
2173 		vput(vp);
2174 		cache_setunresolved(&nd->nl_nch);
2175 		error = cache_resolve(&nd->nl_nch, nd->nl_cred);
2176 		if (error == 0)
2177 			goto again;
2178 	} else {
2179 		vput(vp);
2180 	}
2181 	return (error);
2182 }
2183 
2184 /*
2185  * stat_args(char *path, struct stat *ub)
2186  *
2187  * Get file status; this version follows links.
2188  */
2189 int
2190 sys_stat(struct stat_args *uap)
2191 {
2192 	struct nlookupdata nd;
2193 	struct stat st;
2194 	int error;
2195 
2196 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2197 	if (error == 0) {
2198 		error = kern_stat(&nd, &st);
2199 		if (error == 0)
2200 			error = copyout(&st, uap->ub, sizeof(*uap->ub));
2201 	}
2202 	nlookup_done(&nd);
2203 	return (error);
2204 }
2205 
2206 /*
2207  * lstat_args(char *path, struct stat *ub)
2208  *
2209  * Get file status; this version does not follow links.
2210  */
2211 int
2212 sys_lstat(struct lstat_args *uap)
2213 {
2214 	struct nlookupdata nd;
2215 	struct stat st;
2216 	int error;
2217 
2218 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2219 	if (error == 0) {
2220 		error = kern_stat(&nd, &st);
2221 		if (error == 0)
2222 			error = copyout(&st, uap->ub, sizeof(*uap->ub));
2223 	}
2224 	nlookup_done(&nd);
2225 	return (error);
2226 }
2227 
2228 /*
2229  * pathconf_Args(char *path, int name)
2230  *
2231  * Get configurable pathname variables.
2232  */
2233 /* ARGSUSED */
2234 int
2235 sys_pathconf(struct pathconf_args *uap)
2236 {
2237 	struct nlookupdata nd;
2238 	struct vnode *vp;
2239 	int error;
2240 
2241 	vp = NULL;
2242 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2243 	if (error == 0)
2244 		error = nlookup(&nd);
2245 	if (error == 0)
2246 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
2247 	nlookup_done(&nd);
2248 	if (error == 0) {
2249 		error = VOP_PATHCONF(vp, uap->name, uap->sysmsg_fds);
2250 		vput(vp);
2251 	}
2252 	return (error);
2253 }
2254 
2255 /*
2256  * XXX: daver
2257  * kern_readlink isn't properly split yet.  There is a copyin burried
2258  * in VOP_READLINK().
2259  */
2260 int
2261 kern_readlink(struct nlookupdata *nd, char *buf, int count, int *res)
2262 {
2263 	struct thread *td = curthread;
2264 	struct proc *p = td->td_proc;
2265 	struct vnode *vp;
2266 	struct iovec aiov;
2267 	struct uio auio;
2268 	int error;
2269 
2270 	if ((error = nlookup(nd)) != 0)
2271 		return (error);
2272 	error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_EXCLUSIVE, &vp);
2273 	if (error)
2274 		return (error);
2275 	if (vp->v_type != VLNK) {
2276 		error = EINVAL;
2277 	} else {
2278 		aiov.iov_base = buf;
2279 		aiov.iov_len = count;
2280 		auio.uio_iov = &aiov;
2281 		auio.uio_iovcnt = 1;
2282 		auio.uio_offset = 0;
2283 		auio.uio_rw = UIO_READ;
2284 		auio.uio_segflg = UIO_USERSPACE;
2285 		auio.uio_td = td;
2286 		auio.uio_resid = count;
2287 		error = VOP_READLINK(vp, &auio, p->p_ucred);
2288 	}
2289 	vput(vp);
2290 	*res = count - auio.uio_resid;
2291 	return (error);
2292 }
2293 
2294 /*
2295  * readlink_args(char *path, char *buf, int count)
2296  *
2297  * Return target name of a symbolic link.
2298  */
2299 int
2300 sys_readlink(struct readlink_args *uap)
2301 {
2302 	struct nlookupdata nd;
2303 	int error;
2304 
2305 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2306 	if (error == 0) {
2307 		error = kern_readlink(&nd, uap->buf, uap->count,
2308 					&uap->sysmsg_result);
2309 	}
2310 	nlookup_done(&nd);
2311 	return (error);
2312 }
2313 
2314 static int
2315 setfflags(struct vnode *vp, int flags)
2316 {
2317 	struct thread *td = curthread;
2318 	struct proc *p = td->td_proc;
2319 	int error;
2320 	struct vattr vattr;
2321 
2322 	/*
2323 	 * Prevent non-root users from setting flags on devices.  When
2324 	 * a device is reused, users can retain ownership of the device
2325 	 * if they are allowed to set flags and programs assume that
2326 	 * chown can't fail when done as root.
2327 	 */
2328 	if ((vp->v_type == VCHR || vp->v_type == VBLK) &&
2329 	    ((error = suser_cred(p->p_ucred, PRISON_ROOT)) != 0))
2330 		return (error);
2331 
2332 	/*
2333 	 * note: vget is required for any operation that might mod the vnode
2334 	 * so VINACTIVE is properly cleared.
2335 	 */
2336 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
2337 		VATTR_NULL(&vattr);
2338 		vattr.va_flags = flags;
2339 		error = VOP_SETATTR(vp, &vattr, p->p_ucred);
2340 		vput(vp);
2341 	}
2342 	return (error);
2343 }
2344 
2345 /*
2346  * chflags(char *path, int flags)
2347  *
2348  * Change flags of a file given a path name.
2349  */
2350 /* ARGSUSED */
2351 int
2352 sys_chflags(struct chflags_args *uap)
2353 {
2354 	struct nlookupdata nd;
2355 	struct vnode *vp;
2356 	int error;
2357 
2358 	vp = NULL;
2359 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2360 	/* XXX Add NLC flag indicating modifying operation? */
2361 	if (error == 0)
2362 		error = nlookup(&nd);
2363 	if (error == 0)
2364 		error = ncp_writechk(&nd.nl_nch);
2365 	if (error == 0)
2366 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
2367 	nlookup_done(&nd);
2368 	if (error == 0) {
2369 		error = setfflags(vp, uap->flags);
2370 		vrele(vp);
2371 	}
2372 	return (error);
2373 }
2374 
2375 /*
2376  * fchflags_args(int fd, int flags)
2377  *
2378  * Change flags of a file given a file descriptor.
2379  */
2380 /* ARGSUSED */
2381 int
2382 sys_fchflags(struct fchflags_args *uap)
2383 {
2384 	struct thread *td = curthread;
2385 	struct proc *p = td->td_proc;
2386 	struct file *fp;
2387 	int error;
2388 
2389 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
2390 		return (error);
2391 	if (fp->f_nchandle.ncp)
2392 		error = ncp_writechk(&fp->f_nchandle);
2393 	if (error == 0)
2394 		error = setfflags((struct vnode *) fp->f_data, uap->flags);
2395 	fdrop(fp);
2396 	return (error);
2397 }
2398 
2399 static int
2400 setfmode(struct vnode *vp, int mode)
2401 {
2402 	struct thread *td = curthread;
2403 	struct proc *p = td->td_proc;
2404 	int error;
2405 	struct vattr vattr;
2406 
2407 	/*
2408 	 * note: vget is required for any operation that might mod the vnode
2409 	 * so VINACTIVE is properly cleared.
2410 	 */
2411 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
2412 		VATTR_NULL(&vattr);
2413 		vattr.va_mode = mode & ALLPERMS;
2414 		error = VOP_SETATTR(vp, &vattr, p->p_ucred);
2415 		vput(vp);
2416 	}
2417 	return error;
2418 }
2419 
2420 int
2421 kern_chmod(struct nlookupdata *nd, int mode)
2422 {
2423 	struct vnode *vp;
2424 	int error;
2425 
2426 	/* XXX Add NLC flag indicating modifying operation? */
2427 	if ((error = nlookup(nd)) != 0)
2428 		return (error);
2429 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
2430 		return (error);
2431 	if ((error = ncp_writechk(&nd->nl_nch)) == 0)
2432 		error = setfmode(vp, mode);
2433 	vrele(vp);
2434 	return (error);
2435 }
2436 
2437 /*
2438  * chmod_args(char *path, int mode)
2439  *
2440  * Change mode of a file given path name.
2441  */
2442 /* ARGSUSED */
2443 int
2444 sys_chmod(struct chmod_args *uap)
2445 {
2446 	struct nlookupdata nd;
2447 	int error;
2448 
2449 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2450 	if (error == 0)
2451 		error = kern_chmod(&nd, uap->mode);
2452 	nlookup_done(&nd);
2453 	return (error);
2454 }
2455 
2456 /*
2457  * lchmod_args(char *path, int mode)
2458  *
2459  * Change mode of a file given path name (don't follow links.)
2460  */
2461 /* ARGSUSED */
2462 int
2463 sys_lchmod(struct lchmod_args *uap)
2464 {
2465 	struct nlookupdata nd;
2466 	int error;
2467 
2468 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2469 	if (error == 0)
2470 		error = kern_chmod(&nd, uap->mode);
2471 	nlookup_done(&nd);
2472 	return (error);
2473 }
2474 
2475 /*
2476  * fchmod_args(int fd, int mode)
2477  *
2478  * Change mode of a file given a file descriptor.
2479  */
2480 /* ARGSUSED */
2481 int
2482 sys_fchmod(struct fchmod_args *uap)
2483 {
2484 	struct thread *td = curthread;
2485 	struct proc *p = td->td_proc;
2486 	struct file *fp;
2487 	int error;
2488 
2489 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
2490 		return (error);
2491 	if (fp->f_nchandle.ncp)
2492 		error = ncp_writechk(&fp->f_nchandle);
2493 	if (error == 0)
2494 		error = setfmode((struct vnode *)fp->f_data, uap->mode);
2495 	fdrop(fp);
2496 	return (error);
2497 }
2498 
2499 static int
2500 setfown(struct vnode *vp, uid_t uid, gid_t gid)
2501 {
2502 	struct thread *td = curthread;
2503 	struct proc *p = td->td_proc;
2504 	int error;
2505 	struct vattr vattr;
2506 
2507 	/*
2508 	 * note: vget is required for any operation that might mod the vnode
2509 	 * so VINACTIVE is properly cleared.
2510 	 */
2511 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
2512 		VATTR_NULL(&vattr);
2513 		vattr.va_uid = uid;
2514 		vattr.va_gid = gid;
2515 		error = VOP_SETATTR(vp, &vattr, p->p_ucred);
2516 		vput(vp);
2517 	}
2518 	return error;
2519 }
2520 
2521 int
2522 kern_chown(struct nlookupdata *nd, int uid, int gid)
2523 {
2524 	struct vnode *vp;
2525 	int error;
2526 
2527 	/* XXX Add NLC flag indicating modifying operation? */
2528 	if ((error = nlookup(nd)) != 0)
2529 		return (error);
2530 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
2531 		return (error);
2532 	if ((error = ncp_writechk(&nd->nl_nch)) == 0)
2533 		error = setfown(vp, uid, gid);
2534 	vrele(vp);
2535 	return (error);
2536 }
2537 
2538 /*
2539  * chown(char *path, int uid, int gid)
2540  *
2541  * Set ownership given a path name.
2542  */
2543 int
2544 sys_chown(struct chown_args *uap)
2545 {
2546 	struct nlookupdata nd;
2547 	int error;
2548 
2549 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2550 	if (error == 0)
2551 		error = kern_chown(&nd, uap->uid, uap->gid);
2552 	nlookup_done(&nd);
2553 	return (error);
2554 }
2555 
2556 /*
2557  * lchown_args(char *path, int uid, int gid)
2558  *
2559  * Set ownership given a path name, do not cross symlinks.
2560  */
2561 int
2562 sys_lchown(struct lchown_args *uap)
2563 {
2564 	struct nlookupdata nd;
2565 	int error;
2566 
2567 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2568 	if (error == 0)
2569 		error = kern_chown(&nd, uap->uid, uap->gid);
2570 	nlookup_done(&nd);
2571 	return (error);
2572 }
2573 
2574 /*
2575  * fchown_args(int fd, int uid, int gid)
2576  *
2577  * Set ownership given a file descriptor.
2578  */
2579 /* ARGSUSED */
2580 int
2581 sys_fchown(struct fchown_args *uap)
2582 {
2583 	struct thread *td = curthread;
2584 	struct proc *p = td->td_proc;
2585 	struct file *fp;
2586 	int error;
2587 
2588 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
2589 		return (error);
2590 	if (fp->f_nchandle.ncp)
2591 		error = ncp_writechk(&fp->f_nchandle);
2592 	if (error == 0)
2593 		error = setfown((struct vnode *)fp->f_data, uap->uid, uap->gid);
2594 	fdrop(fp);
2595 	return (error);
2596 }
2597 
2598 static int
2599 getutimes(const struct timeval *tvp, struct timespec *tsp)
2600 {
2601 	struct timeval tv[2];
2602 
2603 	if (tvp == NULL) {
2604 		microtime(&tv[0]);
2605 		TIMEVAL_TO_TIMESPEC(&tv[0], &tsp[0]);
2606 		tsp[1] = tsp[0];
2607 	} else {
2608 		TIMEVAL_TO_TIMESPEC(&tvp[0], &tsp[0]);
2609 		TIMEVAL_TO_TIMESPEC(&tvp[1], &tsp[1]);
2610 	}
2611 	return 0;
2612 }
2613 
2614 static int
2615 setutimes(struct vnode *vp, const struct timespec *ts, int nullflag)
2616 {
2617 	struct thread *td = curthread;
2618 	struct proc *p = td->td_proc;
2619 	int error;
2620 	struct vattr vattr;
2621 
2622 	/*
2623 	 * note: vget is required for any operation that might mod the vnode
2624 	 * so VINACTIVE is properly cleared.
2625 	 */
2626 	if ((error = vget(vp, LK_EXCLUSIVE)) == 0) {
2627 		VATTR_NULL(&vattr);
2628 		vattr.va_atime = ts[0];
2629 		vattr.va_mtime = ts[1];
2630 		if (nullflag)
2631 			vattr.va_vaflags |= VA_UTIMES_NULL;
2632 		error = VOP_SETATTR(vp, &vattr, p->p_ucred);
2633 		vput(vp);
2634 	}
2635 	return error;
2636 }
2637 
2638 int
2639 kern_utimes(struct nlookupdata *nd, struct timeval *tptr)
2640 {
2641 	struct timespec ts[2];
2642 	struct vnode *vp;
2643 	int error;
2644 
2645 	if ((error = getutimes(tptr, ts)) != 0)
2646 		return (error);
2647 	/* XXX Add NLC flag indicating modifying operation? */
2648 	if ((error = nlookup(nd)) != 0)
2649 		return (error);
2650 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2651 		return (error);
2652 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
2653 		return (error);
2654 	error = setutimes(vp, ts, tptr == NULL);
2655 	vrele(vp);
2656 	return (error);
2657 }
2658 
2659 /*
2660  * utimes_args(char *path, struct timeval *tptr)
2661  *
2662  * Set the access and modification times of a file.
2663  */
2664 int
2665 sys_utimes(struct utimes_args *uap)
2666 {
2667 	struct timeval tv[2];
2668 	struct nlookupdata nd;
2669 	int error;
2670 
2671 	if (uap->tptr) {
2672  		error = copyin(uap->tptr, tv, sizeof(tv));
2673 		if (error)
2674 			return (error);
2675 	}
2676 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2677 	if (error == 0)
2678 		error = kern_utimes(&nd, uap->tptr ? tv : NULL);
2679 	nlookup_done(&nd);
2680 	return (error);
2681 }
2682 
2683 /*
2684  * lutimes_args(char *path, struct timeval *tptr)
2685  *
2686  * Set the access and modification times of a file.
2687  */
2688 int
2689 sys_lutimes(struct lutimes_args *uap)
2690 {
2691 	struct timeval tv[2];
2692 	struct nlookupdata nd;
2693 	int error;
2694 
2695 	if (uap->tptr) {
2696 		error = copyin(uap->tptr, tv, sizeof(tv));
2697 		if (error)
2698 			return (error);
2699 	}
2700 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
2701 	if (error == 0)
2702 		error = kern_utimes(&nd, uap->tptr ? tv : NULL);
2703 	nlookup_done(&nd);
2704 	return (error);
2705 }
2706 
2707 int
2708 kern_futimes(int fd, struct timeval *tptr)
2709 {
2710 	struct thread *td = curthread;
2711 	struct proc *p = td->td_proc;
2712 	struct timespec ts[2];
2713 	struct file *fp;
2714 	int error;
2715 
2716 	error = getutimes(tptr, ts);
2717 	if (error)
2718 		return (error);
2719 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
2720 		return (error);
2721 	if (fp->f_nchandle.ncp)
2722 		error = ncp_writechk(&fp->f_nchandle);
2723 	if (error == 0)
2724 		error =  setutimes((struct vnode *)fp->f_data, ts, tptr == NULL);
2725 	fdrop(fp);
2726 	return (error);
2727 }
2728 
2729 /*
2730  * futimes_args(int fd, struct timeval *tptr)
2731  *
2732  * Set the access and modification times of a file.
2733  */
2734 int
2735 sys_futimes(struct futimes_args *uap)
2736 {
2737 	struct timeval tv[2];
2738 	int error;
2739 
2740 	if (uap->tptr) {
2741 		error = copyin(uap->tptr, tv, sizeof(tv));
2742 		if (error)
2743 			return (error);
2744 	}
2745 
2746 	error = kern_futimes(uap->fd, uap->tptr ? tv : NULL);
2747 
2748 	return (error);
2749 }
2750 
2751 int
2752 kern_truncate(struct nlookupdata *nd, off_t length)
2753 {
2754 	struct vnode *vp;
2755 	struct vattr vattr;
2756 	int error;
2757 
2758 	if (length < 0)
2759 		return(EINVAL);
2760 	/* XXX Add NLC flag indicating modifying operation? */
2761 	if ((error = nlookup(nd)) != 0)
2762 		return (error);
2763 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
2764 		return (error);
2765 	if ((error = cache_vref(&nd->nl_nch, nd->nl_cred, &vp)) != 0)
2766 		return (error);
2767 	if ((error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY)) != 0) {
2768 		vrele(vp);
2769 		return (error);
2770 	}
2771 	if (vp->v_type == VDIR) {
2772 		error = EISDIR;
2773 	} else if ((error = vn_writechk(vp, &nd->nl_nch)) == 0 &&
2774 	    (error = VOP_ACCESS(vp, VWRITE, nd->nl_cred)) == 0) {
2775 		VATTR_NULL(&vattr);
2776 		vattr.va_size = length;
2777 		error = VOP_SETATTR(vp, &vattr, nd->nl_cred);
2778 	}
2779 	vput(vp);
2780 	return (error);
2781 }
2782 
2783 /*
2784  * truncate(char *path, int pad, off_t length)
2785  *
2786  * Truncate a file given its path name.
2787  */
2788 int
2789 sys_truncate(struct truncate_args *uap)
2790 {
2791 	struct nlookupdata nd;
2792 	int error;
2793 
2794 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
2795 	if (error == 0)
2796 		error = kern_truncate(&nd, uap->length);
2797 	nlookup_done(&nd);
2798 	return error;
2799 }
2800 
2801 int
2802 kern_ftruncate(int fd, off_t length)
2803 {
2804 	struct thread *td = curthread;
2805 	struct proc *p = td->td_proc;
2806 	struct vattr vattr;
2807 	struct vnode *vp;
2808 	struct file *fp;
2809 	int error;
2810 
2811 	if (length < 0)
2812 		return(EINVAL);
2813 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
2814 		return (error);
2815 	if (fp->f_nchandle.ncp) {
2816 		error = ncp_writechk(&fp->f_nchandle);
2817 		if (error)
2818 			goto done;
2819 	}
2820 	if ((fp->f_flag & FWRITE) == 0) {
2821 		error = EINVAL;
2822 		goto done;
2823 	}
2824 	vp = (struct vnode *)fp->f_data;
2825 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2826 	if (vp->v_type == VDIR) {
2827 		error = EISDIR;
2828 	} else if ((error = vn_writechk(vp, NULL)) == 0) {
2829 		VATTR_NULL(&vattr);
2830 		vattr.va_size = length;
2831 		error = VOP_SETATTR(vp, &vattr, fp->f_cred);
2832 	}
2833 	vn_unlock(vp);
2834 done:
2835 	fdrop(fp);
2836 	return (error);
2837 }
2838 
2839 /*
2840  * ftruncate_args(int fd, int pad, off_t length)
2841  *
2842  * Truncate a file given a file descriptor.
2843  */
2844 int
2845 sys_ftruncate(struct ftruncate_args *uap)
2846 {
2847 	int error;
2848 
2849 	error = kern_ftruncate(uap->fd, uap->length);
2850 
2851 	return (error);
2852 }
2853 
2854 /*
2855  * fsync(int fd)
2856  *
2857  * Sync an open file.
2858  */
2859 /* ARGSUSED */
2860 int
2861 sys_fsync(struct fsync_args *uap)
2862 {
2863 	struct thread *td = curthread;
2864 	struct proc *p = td->td_proc;
2865 	struct vnode *vp;
2866 	struct file *fp;
2867 	vm_object_t obj;
2868 	int error;
2869 
2870 	if ((error = holdvnode(p->p_fd, uap->fd, &fp)) != 0)
2871 		return (error);
2872 	vp = (struct vnode *)fp->f_data;
2873 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2874 	if ((obj = vp->v_object) != NULL)
2875 		vm_object_page_clean(obj, 0, 0, 0);
2876 	if ((error = VOP_FSYNC(vp, MNT_WAIT)) == 0 && vp->v_mount)
2877 		error = buf_fsync(vp);
2878 	vn_unlock(vp);
2879 	fdrop(fp);
2880 	return (error);
2881 }
2882 
2883 int
2884 kern_rename(struct nlookupdata *fromnd, struct nlookupdata *tond)
2885 {
2886 	struct nchandle fnchd;
2887 	struct nchandle tnchd;
2888 	struct namecache *ncp;
2889 	struct vnode *fdvp;
2890 	struct vnode *tdvp;
2891 	struct mount *mp;
2892 	int error;
2893 
2894 	bwillwrite();
2895 	if ((error = nlookup(fromnd)) != 0)
2896 		return (error);
2897 	if ((fnchd.ncp = fromnd->nl_nch.ncp->nc_parent) == NULL)
2898 		return (ENOENT);
2899 	fnchd.mount = fromnd->nl_nch.mount;
2900 	cache_hold(&fnchd);
2901 
2902 	/*
2903 	 * unlock the source nch so we can lookup the target nch without
2904 	 * deadlocking.  The target may or may not exist so we do not check
2905 	 * for a target vp like kern_mkdir() and other creation functions do.
2906 	 *
2907 	 * The source and target directories are ref'd and rechecked after
2908 	 * everything is relocked to determine if the source or target file
2909 	 * has been renamed.
2910 	 */
2911 	KKASSERT(fromnd->nl_flags & NLC_NCPISLOCKED);
2912 	fromnd->nl_flags &= ~NLC_NCPISLOCKED;
2913 	cache_unlock(&fromnd->nl_nch);
2914 
2915 	tond->nl_flags |= NLC_CREATE;
2916 	if ((error = nlookup(tond)) != 0) {
2917 		cache_drop(&fnchd);
2918 		return (error);
2919 	}
2920 	if ((tnchd.ncp = tond->nl_nch.ncp->nc_parent) == NULL) {
2921 		cache_drop(&fnchd);
2922 		return (ENOENT);
2923 	}
2924 	tnchd.mount = tond->nl_nch.mount;
2925 	cache_hold(&tnchd);
2926 
2927 	/*
2928 	 * If the source and target are the same there is nothing to do
2929 	 */
2930 	if (fromnd->nl_nch.ncp == tond->nl_nch.ncp) {
2931 		cache_drop(&fnchd);
2932 		cache_drop(&tnchd);
2933 		return (0);
2934 	}
2935 
2936 	/*
2937 	 * Mount points cannot be renamed or overwritten
2938 	 */
2939 	if ((fromnd->nl_nch.ncp->nc_flag | tond->nl_nch.ncp->nc_flag) &
2940 	    NCF_ISMOUNTPT
2941 	) {
2942 		cache_drop(&fnchd);
2943 		cache_drop(&tnchd);
2944 		return (EINVAL);
2945 	}
2946 
2947 	/*
2948 	 * relock the source ncp.  NOTE AFTER RELOCKING: the source ncp
2949 	 * may have become invalid while it was unlocked, nc_vp and nc_mount
2950 	 * could be NULL.
2951 	 */
2952 	if (cache_lock_nonblock(&fromnd->nl_nch) == 0) {
2953 		cache_resolve(&fromnd->nl_nch, fromnd->nl_cred);
2954 	} else if (fromnd->nl_nch.ncp > tond->nl_nch.ncp) {
2955 		cache_lock(&fromnd->nl_nch);
2956 		cache_resolve(&fromnd->nl_nch, fromnd->nl_cred);
2957 	} else {
2958 		cache_unlock(&tond->nl_nch);
2959 		cache_lock(&fromnd->nl_nch);
2960 		cache_resolve(&fromnd->nl_nch, fromnd->nl_cred);
2961 		cache_lock(&tond->nl_nch);
2962 		cache_resolve(&tond->nl_nch, tond->nl_cred);
2963 	}
2964 	fromnd->nl_flags |= NLC_NCPISLOCKED;
2965 
2966 	/*
2967 	 * make sure the parent directories linkages are the same
2968 	 */
2969 	if (fnchd.ncp != fromnd->nl_nch.ncp->nc_parent ||
2970 	    tnchd.ncp != tond->nl_nch.ncp->nc_parent) {
2971 		cache_drop(&fnchd);
2972 		cache_drop(&tnchd);
2973 		return (ENOENT);
2974 	}
2975 
2976 	/*
2977 	 * Both the source and target must be within the same filesystem and
2978 	 * in the same filesystem as their parent directories within the
2979 	 * namecache topology.
2980 	 *
2981 	 * NOTE: fromnd's nc_mount or nc_vp could be NULL.
2982 	 */
2983 	mp = fnchd.mount;
2984 	if (mp != tnchd.mount || mp != fromnd->nl_nch.mount ||
2985 	    mp != tond->nl_nch.mount) {
2986 		cache_drop(&fnchd);
2987 		cache_drop(&tnchd);
2988 		return (EXDEV);
2989 	}
2990 
2991 	/*
2992 	 * Make sure the mount point is writable
2993 	 */
2994 	if ((error = ncp_writechk(&tond->nl_nch)) != 0) {
2995 		cache_drop(&fnchd);
2996 		cache_drop(&tnchd);
2997 		return (error);
2998 	}
2999 
3000 	/*
3001 	 * If the target exists and either the source or target is a directory,
3002 	 * then both must be directories.
3003 	 *
3004 	 * Due to relocking of the source, fromnd->nl_nch.ncp->nc_vp might h
3005 	 * have become NULL.
3006 	 */
3007 	if (tond->nl_nch.ncp->nc_vp) {
3008 		if (fromnd->nl_nch.ncp->nc_vp == NULL) {
3009 			error = ENOENT;
3010 		} else if (fromnd->nl_nch.ncp->nc_vp->v_type == VDIR) {
3011 			if (tond->nl_nch.ncp->nc_vp->v_type != VDIR)
3012 				error = ENOTDIR;
3013 		} else if (tond->nl_nch.ncp->nc_vp->v_type == VDIR) {
3014 			error = EISDIR;
3015 		}
3016 	}
3017 
3018 	/*
3019 	 * You cannot rename a source into itself or a subdirectory of itself.
3020 	 * We check this by travsersing the target directory upwards looking
3021 	 * for a match against the source.
3022 	 */
3023 	if (error == 0) {
3024 		for (ncp = tnchd.ncp; ncp; ncp = ncp->nc_parent) {
3025 			if (fromnd->nl_nch.ncp == ncp) {
3026 				error = EINVAL;
3027 				break;
3028 			}
3029 		}
3030 	}
3031 
3032 	cache_drop(&fnchd);
3033 	cache_drop(&tnchd);
3034 
3035 	/*
3036 	 * Even though the namespaces are different, they may still represent
3037 	 * hardlinks to the same file.  The filesystem might have a hard time
3038 	 * with this so we issue a NREMOVE of the source instead of a NRENAME
3039 	 * when we detect the situation.
3040 	 */
3041 	if (error == 0) {
3042 		fdvp = fromnd->nl_nch.ncp->nc_parent->nc_vp;
3043 		tdvp = tond->nl_nch.ncp->nc_parent->nc_vp;
3044 		if (fdvp == NULL || tdvp == NULL) {
3045 			error = EPERM;
3046 		} else if (fromnd->nl_nch.ncp->nc_vp == tond->nl_nch.ncp->nc_vp) {
3047 			/* vhold(fdvp); - dvp can't go away */
3048 			error = VOP_NREMOVE(&fromnd->nl_nch, fdvp,
3049 					    fromnd->nl_cred);
3050 			/* vdrop(fdvp); */
3051 		} else {
3052 			/* vhold(fdvp); - dvp can't go away */
3053 			/* vhold(tdvp); - dvp can't go away */
3054 			error = VOP_NRENAME(&fromnd->nl_nch, &tond->nl_nch,
3055 					    fdvp, tdvp, tond->nl_cred);
3056 			/* vdrop(fdvp); */
3057 			/* vdrop(tdvp); */
3058 		}
3059 	}
3060 	return (error);
3061 }
3062 
3063 /*
3064  * rename_args(char *from, char *to)
3065  *
3066  * Rename files.  Source and destination must either both be directories,
3067  * or both not be directories.  If target is a directory, it must be empty.
3068  */
3069 int
3070 sys_rename(struct rename_args *uap)
3071 {
3072 	struct nlookupdata fromnd, tond;
3073 	int error;
3074 
3075 	error = nlookup_init(&fromnd, uap->from, UIO_USERSPACE, 0);
3076 	if (error == 0) {
3077 		error = nlookup_init(&tond, uap->to, UIO_USERSPACE, 0);
3078 		if (error == 0)
3079 			error = kern_rename(&fromnd, &tond);
3080 		nlookup_done(&tond);
3081 	}
3082 	nlookup_done(&fromnd);
3083 	return (error);
3084 }
3085 
3086 int
3087 kern_mkdir(struct nlookupdata *nd, int mode)
3088 {
3089 	struct thread *td = curthread;
3090 	struct proc *p = td->td_proc;
3091 	struct vnode *vp;
3092 	struct vnode *dvp;
3093 	struct vattr vattr;
3094 	int error;
3095 
3096 	bwillwrite();
3097 	nd->nl_flags |= NLC_WILLBEDIR | NLC_CREATE;
3098 	if ((error = nlookup(nd)) != 0)
3099 		return (error);
3100 
3101 	if (nd->nl_nch.ncp->nc_vp)
3102 		return (EEXIST);
3103 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3104 		return (error);
3105 	if ((dvp = nd->nl_nch.ncp->nc_parent->nc_vp) == NULL)
3106 		return (EPERM);
3107 	/* vhold(dvp); - dvp can't go away */
3108 	VATTR_NULL(&vattr);
3109 	vattr.va_type = VDIR;
3110 	vattr.va_mode = (mode & ACCESSPERMS) &~ p->p_fd->fd_cmask;
3111 
3112 	vp = NULL;
3113 	error = VOP_NMKDIR(&nd->nl_nch, dvp, &vp, p->p_ucred, &vattr);
3114 	/* vdrop(dvp); */
3115 	if (error == 0)
3116 		vput(vp);
3117 	return (error);
3118 }
3119 
3120 /*
3121  * mkdir_args(char *path, int mode)
3122  *
3123  * Make a directory file.
3124  */
3125 /* ARGSUSED */
3126 int
3127 sys_mkdir(struct mkdir_args *uap)
3128 {
3129 	struct nlookupdata nd;
3130 	int error;
3131 
3132 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3133 	if (error == 0)
3134 		error = kern_mkdir(&nd, uap->mode);
3135 	nlookup_done(&nd);
3136 	return (error);
3137 }
3138 
3139 int
3140 kern_rmdir(struct nlookupdata *nd)
3141 {
3142 	struct vnode *dvp;
3143 	int error;
3144 
3145 	bwillwrite();
3146 	nd->nl_flags |= NLC_DELETE;
3147 	if ((error = nlookup(nd)) != 0)
3148 		return (error);
3149 
3150 	/*
3151 	 * Do not allow directories representing mount points to be
3152 	 * deleted, even if empty.  Check write perms on mount point
3153 	 * in case the vnode is aliased (aka nullfs).
3154 	 */
3155 	if (nd->nl_nch.ncp->nc_flag & (NCF_ISMOUNTPT))
3156 		return (EINVAL);
3157 	if ((error = ncp_writechk(&nd->nl_nch)) != 0)
3158 		return (error);
3159 	if ((dvp = nd->nl_nch.ncp->nc_parent->nc_vp) == NULL)
3160 		return (EPERM);
3161 	/* vhold(dvp); - dvp can't go away */
3162 	error = VOP_NRMDIR(&nd->nl_nch, dvp, nd->nl_cred);
3163 	/* vdrop(dvp); */
3164 	return (error);
3165 }
3166 
3167 /*
3168  * rmdir_args(char *path)
3169  *
3170  * Remove a directory file.
3171  */
3172 /* ARGSUSED */
3173 int
3174 sys_rmdir(struct rmdir_args *uap)
3175 {
3176 	struct nlookupdata nd;
3177 	int error;
3178 
3179 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 0);
3180 	if (error == 0)
3181 		error = kern_rmdir(&nd);
3182 	nlookup_done(&nd);
3183 	return (error);
3184 }
3185 
3186 int
3187 kern_getdirentries(int fd, char *buf, u_int count, long *basep, int *res,
3188     enum uio_seg direction)
3189 {
3190 	struct thread *td = curthread;
3191 	struct proc *p = td->td_proc;
3192 	struct vnode *vp;
3193 	struct file *fp;
3194 	struct uio auio;
3195 	struct iovec aiov;
3196 	off_t loff;
3197 	int error, eofflag;
3198 
3199 	if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
3200 		return (error);
3201 	if ((fp->f_flag & FREAD) == 0) {
3202 		error = EBADF;
3203 		goto done;
3204 	}
3205 	vp = (struct vnode *)fp->f_data;
3206 unionread:
3207 	if (vp->v_type != VDIR) {
3208 		error = EINVAL;
3209 		goto done;
3210 	}
3211 	aiov.iov_base = buf;
3212 	aiov.iov_len = count;
3213 	auio.uio_iov = &aiov;
3214 	auio.uio_iovcnt = 1;
3215 	auio.uio_rw = UIO_READ;
3216 	auio.uio_segflg = direction;
3217 	auio.uio_td = td;
3218 	auio.uio_resid = count;
3219 	loff = auio.uio_offset = fp->f_offset;
3220 	error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, NULL, NULL);
3221 	fp->f_offset = auio.uio_offset;
3222 	if (error)
3223 		goto done;
3224 	if (count == auio.uio_resid) {
3225 		if (union_dircheckp) {
3226 			error = union_dircheckp(td, &vp, fp);
3227 			if (error == -1)
3228 				goto unionread;
3229 			if (error)
3230 				goto done;
3231 		}
3232 #if 0
3233 		if ((vp->v_flag & VROOT) &&
3234 		    (vp->v_mount->mnt_flag & MNT_UNION)) {
3235 			struct vnode *tvp = vp;
3236 			vp = vp->v_mount->mnt_vnodecovered;
3237 			vref(vp);
3238 			fp->f_data = vp;
3239 			fp->f_offset = 0;
3240 			vrele(tvp);
3241 			goto unionread;
3242 		}
3243 #endif
3244 	}
3245 
3246 	/*
3247 	 * WARNING!  *basep may not be wide enough to accomodate the
3248 	 * seek offset.   XXX should we hack this to return the upper 32 bits
3249 	 * for offsets greater then 4G?
3250 	 */
3251 	if (basep) {
3252 		*basep = (long)loff;
3253 	}
3254 	*res = count - auio.uio_resid;
3255 done:
3256 	fdrop(fp);
3257 	return (error);
3258 }
3259 
3260 /*
3261  * getdirentries_args(int fd, char *buf, u_int conut, long *basep)
3262  *
3263  * Read a block of directory entries in a file system independent format.
3264  */
3265 int
3266 sys_getdirentries(struct getdirentries_args *uap)
3267 {
3268 	long base;
3269 	int error;
3270 
3271 	error = kern_getdirentries(uap->fd, uap->buf, uap->count, &base,
3272 				   &uap->sysmsg_result, UIO_USERSPACE);
3273 
3274 	if (error == 0 && uap->basep)
3275 		error = copyout(&base, uap->basep, sizeof(*uap->basep));
3276 	return (error);
3277 }
3278 
3279 /*
3280  * getdents_args(int fd, char *buf, size_t count)
3281  */
3282 int
3283 sys_getdents(struct getdents_args *uap)
3284 {
3285 	int error;
3286 
3287 	error = kern_getdirentries(uap->fd, uap->buf, uap->count, NULL,
3288 	    &uap->sysmsg_result, UIO_USERSPACE);
3289 
3290 	return (error);
3291 }
3292 
3293 /*
3294  * umask(int newmask)
3295  *
3296  * Set the mode mask for creation of filesystem nodes.
3297  *
3298  * MP SAFE
3299  */
3300 int
3301 sys_umask(struct umask_args *uap)
3302 {
3303 	struct thread *td = curthread;
3304 	struct proc *p = td->td_proc;
3305 	struct filedesc *fdp;
3306 
3307 	fdp = p->p_fd;
3308 	uap->sysmsg_result = fdp->fd_cmask;
3309 	fdp->fd_cmask = uap->newmask & ALLPERMS;
3310 	return (0);
3311 }
3312 
3313 /*
3314  * revoke(char *path)
3315  *
3316  * Void all references to file by ripping underlying filesystem
3317  * away from vnode.
3318  */
3319 /* ARGSUSED */
3320 int
3321 sys_revoke(struct revoke_args *uap)
3322 {
3323 	struct nlookupdata nd;
3324 	struct vattr vattr;
3325 	struct vnode *vp;
3326 	struct ucred *cred;
3327 	int error;
3328 
3329 	vp = NULL;
3330 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3331 	if (error == 0)
3332 		error = nlookup(&nd);
3333 	if (error == 0)
3334 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
3335 	cred = crhold(nd.nl_cred);
3336 	nlookup_done(&nd);
3337 	if (error == 0) {
3338 		if (vp->v_type != VCHR && vp->v_type != VBLK)
3339 			error = EINVAL;
3340 		if (error == 0)
3341 			error = VOP_GETATTR(vp, &vattr);
3342 		if (error == 0 && cred->cr_uid != vattr.va_uid)
3343 			error = suser_cred(cred, PRISON_ROOT);
3344 		if (error == 0 && count_udev(vp->v_umajor, vp->v_uminor) > 0) {
3345 			error = 0;
3346 			vx_lock(vp);
3347 			VOP_REVOKE(vp, REVOKEALL);
3348 			vx_unlock(vp);
3349 		}
3350 		vrele(vp);
3351 	}
3352 	if (cred)
3353 		crfree(cred);
3354 	return (error);
3355 }
3356 
3357 /*
3358  * getfh_args(char *fname, fhandle_t *fhp)
3359  *
3360  * Get (NFS) file handle
3361  */
3362 int
3363 sys_getfh(struct getfh_args *uap)
3364 {
3365 	struct thread *td = curthread;
3366 	struct nlookupdata nd;
3367 	fhandle_t fh;
3368 	struct vnode *vp;
3369 	int error;
3370 
3371 	/*
3372 	 * Must be super user
3373 	 */
3374 	if ((error = suser(td)) != 0)
3375 		return (error);
3376 
3377 	vp = NULL;
3378 	error = nlookup_init(&nd, uap->fname, UIO_USERSPACE, NLC_FOLLOW);
3379 	if (error == 0)
3380 		error = nlookup(&nd);
3381 	if (error == 0)
3382 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
3383 	nlookup_done(&nd);
3384 	if (error == 0) {
3385 		bzero(&fh, sizeof(fh));
3386 		fh.fh_fsid = vp->v_mount->mnt_stat.f_fsid;
3387 		error = VFS_VPTOFH(vp, &fh.fh_fid);
3388 		vput(vp);
3389 		if (error == 0)
3390 			error = copyout(&fh, uap->fhp, sizeof(fh));
3391 	}
3392 	return (error);
3393 }
3394 
3395 /*
3396  * fhopen_args(const struct fhandle *u_fhp, int flags)
3397  *
3398  * syscall for the rpc.lockd to use to translate a NFS file handle into
3399  * an open descriptor.
3400  *
3401  * warning: do not remove the suser() call or this becomes one giant
3402  * security hole.
3403  */
3404 int
3405 sys_fhopen(struct fhopen_args *uap)
3406 {
3407 	struct thread *td = curthread;
3408 	struct proc *p = td->td_proc;
3409 	struct mount *mp;
3410 	struct vnode *vp;
3411 	struct fhandle fhp;
3412 	struct vattr vat;
3413 	struct vattr *vap = &vat;
3414 	struct flock lf;
3415 	int fmode, mode, error, type;
3416 	struct file *nfp;
3417 	struct file *fp;
3418 	int indx;
3419 
3420 	/*
3421 	 * Must be super user
3422 	 */
3423 	error = suser(td);
3424 	if (error)
3425 		return (error);
3426 
3427 	fmode = FFLAGS(uap->flags);
3428 	/* why not allow a non-read/write open for our lockd? */
3429 	if (((fmode & (FREAD | FWRITE)) == 0) || (fmode & O_CREAT))
3430 		return (EINVAL);
3431 	error = copyin(uap->u_fhp, &fhp, sizeof(fhp));
3432 	if (error)
3433 		return(error);
3434 	/* find the mount point */
3435 	mp = vfs_getvfs(&fhp.fh_fsid);
3436 	if (mp == NULL)
3437 		return (ESTALE);
3438 	/* now give me my vnode, it gets returned to me locked */
3439 	error = VFS_FHTOVP(mp, &fhp.fh_fid, &vp);
3440 	if (error)
3441 		return (error);
3442  	/*
3443 	 * from now on we have to make sure not
3444 	 * to forget about the vnode
3445 	 * any error that causes an abort must vput(vp)
3446 	 * just set error = err and 'goto bad;'.
3447 	 */
3448 
3449 	/*
3450 	 * from vn_open
3451 	 */
3452 	if (vp->v_type == VLNK) {
3453 		error = EMLINK;
3454 		goto bad;
3455 	}
3456 	if (vp->v_type == VSOCK) {
3457 		error = EOPNOTSUPP;
3458 		goto bad;
3459 	}
3460 	mode = 0;
3461 	if (fmode & (FWRITE | O_TRUNC)) {
3462 		if (vp->v_type == VDIR) {
3463 			error = EISDIR;
3464 			goto bad;
3465 		}
3466 		error = vn_writechk(vp, NULL);
3467 		if (error)
3468 			goto bad;
3469 		mode |= VWRITE;
3470 	}
3471 	if (fmode & FREAD)
3472 		mode |= VREAD;
3473 	if (mode) {
3474 		error = VOP_ACCESS(vp, mode, p->p_ucred);
3475 		if (error)
3476 			goto bad;
3477 	}
3478 	if (fmode & O_TRUNC) {
3479 		vn_unlock(vp);				/* XXX */
3480 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);	/* XXX */
3481 		VATTR_NULL(vap);
3482 		vap->va_size = 0;
3483 		error = VOP_SETATTR(vp, vap, p->p_ucred);
3484 		if (error)
3485 			goto bad;
3486 	}
3487 
3488 	/*
3489 	 * VOP_OPEN needs the file pointer so it can potentially override
3490 	 * it.
3491 	 *
3492 	 * WARNING! no f_nchandle will be associated when fhopen()ing a
3493 	 * directory.  XXX
3494 	 */
3495 	if ((error = falloc(p, &nfp, &indx)) != 0)
3496 		goto bad;
3497 	fp = nfp;
3498 
3499 	error = VOP_OPEN(vp, fmode, p->p_ucred, fp);
3500 	if (error) {
3501 		/*
3502 		 * setting f_ops this way prevents VOP_CLOSE from being
3503 		 * called or fdrop() releasing the vp from v_data.   Since
3504 		 * the VOP_OPEN failed we don't want to VOP_CLOSE.
3505 		 */
3506 		fp->f_ops = &badfileops;
3507 		fp->f_data = NULL;
3508 		goto bad_drop;
3509 	}
3510 
3511 	/*
3512 	 * The fp is given its own reference, we still have our ref and lock.
3513 	 *
3514 	 * Assert that all regular files must be created with a VM object.
3515 	 */
3516 	if (vp->v_type == VREG && vp->v_object == NULL) {
3517 		kprintf("fhopen: regular file did not have VM object: %p\n", vp);
3518 		goto bad_drop;
3519 	}
3520 
3521 	/*
3522 	 * The open was successful.  Handle any locking requirements.
3523 	 */
3524 	if (fmode & (O_EXLOCK | O_SHLOCK)) {
3525 		lf.l_whence = SEEK_SET;
3526 		lf.l_start = 0;
3527 		lf.l_len = 0;
3528 		if (fmode & O_EXLOCK)
3529 			lf.l_type = F_WRLCK;
3530 		else
3531 			lf.l_type = F_RDLCK;
3532 		if (fmode & FNONBLOCK)
3533 			type = 0;
3534 		else
3535 			type = F_WAIT;
3536 		vn_unlock(vp);
3537 		if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0) {
3538 			/*
3539 			 * release our private reference.
3540 			 */
3541 			fsetfd(p, NULL, indx);
3542 			fdrop(fp);
3543 			vrele(vp);
3544 			return (error);
3545 		}
3546 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3547 		fp->f_flag |= FHASLOCK;
3548 	}
3549 
3550 	/*
3551 	 * Clean up.  Associate the file pointer with the previously
3552 	 * reserved descriptor and return it.
3553 	 */
3554 	vput(vp);
3555 	fsetfd(p, fp, indx);
3556 	fdrop(fp);
3557 	uap->sysmsg_result = indx;
3558 	return (0);
3559 
3560 bad_drop:
3561 	fsetfd(p, NULL, indx);
3562 	fdrop(fp);
3563 bad:
3564 	vput(vp);
3565 	return (error);
3566 }
3567 
3568 /*
3569  * fhstat_args(struct fhandle *u_fhp, struct stat *sb)
3570  */
3571 int
3572 sys_fhstat(struct fhstat_args *uap)
3573 {
3574 	struct thread *td = curthread;
3575 	struct stat sb;
3576 	fhandle_t fh;
3577 	struct mount *mp;
3578 	struct vnode *vp;
3579 	int error;
3580 
3581 	/*
3582 	 * Must be super user
3583 	 */
3584 	error = suser(td);
3585 	if (error)
3586 		return (error);
3587 
3588 	error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t));
3589 	if (error)
3590 		return (error);
3591 
3592 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL)
3593 		return (ESTALE);
3594 	if ((error = VFS_FHTOVP(mp, &fh.fh_fid, &vp)))
3595 		return (error);
3596 	error = vn_stat(vp, &sb, td->td_proc->p_ucred);
3597 	vput(vp);
3598 	if (error)
3599 		return (error);
3600 	error = copyout(&sb, uap->sb, sizeof(sb));
3601 	return (error);
3602 }
3603 
3604 /*
3605  * fhstatfs_args(struct fhandle *u_fhp, struct statfs *buf)
3606  */
3607 int
3608 sys_fhstatfs(struct fhstatfs_args *uap)
3609 {
3610 	struct thread *td = curthread;
3611 	struct proc *p = td->td_proc;
3612 	struct statfs *sp;
3613 	struct mount *mp;
3614 	struct vnode *vp;
3615 	struct statfs sb;
3616 	char *fullpath, *freepath;
3617 	fhandle_t fh;
3618 	int error;
3619 
3620 	/*
3621 	 * Must be super user
3622 	 */
3623 	if ((error = suser(td)))
3624 		return (error);
3625 
3626 	if ((error = copyin(uap->u_fhp, &fh, sizeof(fhandle_t))) != 0)
3627 		return (error);
3628 
3629 	if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL)
3630 		return (ESTALE);
3631 
3632 	if (p != NULL && !chroot_visible_mnt(mp, p))
3633 		return (ESTALE);
3634 
3635 	if ((error = VFS_FHTOVP(mp, &fh.fh_fid, &vp)))
3636 		return (error);
3637 	mp = vp->v_mount;
3638 	sp = &mp->mnt_stat;
3639 	vput(vp);
3640 	if ((error = VFS_STATFS(mp, sp, p->p_ucred)) != 0)
3641 		return (error);
3642 
3643 	error = mount_path(p, mp, &fullpath, &freepath);
3644 	if (error)
3645 		return(error);
3646 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
3647 	strlcpy(sp->f_mntonname, fullpath, sizeof(sp->f_mntonname));
3648 	kfree(freepath, M_TEMP);
3649 
3650 	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
3651 	if (suser(td)) {
3652 		bcopy(sp, &sb, sizeof(sb));
3653 		sb.f_fsid.val[0] = sb.f_fsid.val[1] = 0;
3654 		sp = &sb;
3655 	}
3656 	return (copyout(sp, uap->buf, sizeof(*sp)));
3657 }
3658 
3659 /*
3660  * Syscall to push extended attribute configuration information into the
3661  * VFS.  Accepts a path, which it converts to a mountpoint, as well as
3662  * a command (int cmd), and attribute name and misc data.  For now, the
3663  * attribute name is left in userspace for consumption by the VFS_op.
3664  * It will probably be changed to be copied into sysspace by the
3665  * syscall in the future, once issues with various consumers of the
3666  * attribute code have raised their hands.
3667  *
3668  * Currently this is used only by UFS Extended Attributes.
3669  */
3670 int
3671 sys_extattrctl(struct extattrctl_args *uap)
3672 {
3673 	struct nlookupdata nd;
3674 	struct mount *mp;
3675 	struct vnode *vp;
3676 	int error;
3677 
3678 	vp = NULL;
3679 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3680 	if (error == 0)
3681 		error = nlookup(&nd);
3682 	if (error == 0) {
3683 		mp = nd.nl_nch.mount;
3684 		error = VFS_EXTATTRCTL(mp, uap->cmd,
3685 				uap->attrname, uap->arg,
3686 				nd.nl_cred);
3687 	}
3688 	nlookup_done(&nd);
3689 	return (error);
3690 }
3691 
3692 /*
3693  * Syscall to set a named extended attribute on a file or directory.
3694  * Accepts attribute name, and a uio structure pointing to the data to set.
3695  * The uio is consumed in the style of writev().  The real work happens
3696  * in VOP_SETEXTATTR().
3697  */
3698 int
3699 sys_extattr_set_file(struct extattr_set_file_args *uap)
3700 {
3701 	char attrname[EXTATTR_MAXNAMELEN];
3702 	struct iovec aiov[UIO_SMALLIOV];
3703 	struct iovec *needfree;
3704 	struct nlookupdata nd;
3705 	struct iovec *iov;
3706 	struct vnode *vp;
3707 	struct uio auio;
3708 	u_int iovlen;
3709 	u_int cnt;
3710 	int error;
3711 	int i;
3712 
3713 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
3714 	if (error)
3715 		return (error);
3716 
3717 	vp = NULL;
3718 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3719 	if (error == 0)
3720 		error = nlookup(&nd);
3721 	if (error == 0)
3722 		error = ncp_writechk(&nd.nl_nch);
3723 	if (error == 0)
3724 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
3725 	if (error) {
3726 		nlookup_done(&nd);
3727 		return (error);
3728 	}
3729 
3730 	needfree = NULL;
3731 	iovlen = uap->iovcnt * sizeof(struct iovec);
3732 	if (uap->iovcnt > UIO_SMALLIOV) {
3733 		if (uap->iovcnt > UIO_MAXIOV) {
3734 			error = EINVAL;
3735 			goto done;
3736 		}
3737 		MALLOC(iov, struct iovec *, iovlen, M_IOV, M_WAITOK);
3738 		needfree = iov;
3739 	} else {
3740 		iov = aiov;
3741 	}
3742 	auio.uio_iov = iov;
3743 	auio.uio_iovcnt = uap->iovcnt;
3744 	auio.uio_rw = UIO_WRITE;
3745 	auio.uio_segflg = UIO_USERSPACE;
3746 	auio.uio_td = nd.nl_td;
3747 	auio.uio_offset = 0;
3748 	if ((error = copyin(uap->iovp, iov, iovlen)))
3749 		goto done;
3750 	auio.uio_resid = 0;
3751 	for (i = 0; i < uap->iovcnt; i++) {
3752 		if (iov->iov_len > INT_MAX - auio.uio_resid) {
3753 			error = EINVAL;
3754 			goto done;
3755 		}
3756 		auio.uio_resid += iov->iov_len;
3757 		iov++;
3758 	}
3759 	cnt = auio.uio_resid;
3760 	error = VOP_SETEXTATTR(vp, attrname, &auio, nd.nl_cred);
3761 	cnt -= auio.uio_resid;
3762 	uap->sysmsg_result = cnt;
3763 done:
3764 	vput(vp);
3765 	nlookup_done(&nd);
3766 	if (needfree)
3767 		FREE(needfree, M_IOV);
3768 	return (error);
3769 }
3770 
3771 /*
3772  * Syscall to get a named extended attribute on a file or directory.
3773  * Accepts attribute name, and a uio structure pointing to a buffer for the
3774  * data.  The uio is consumed in the style of readv().  The real work
3775  * happens in VOP_GETEXTATTR();
3776  */
3777 int
3778 sys_extattr_get_file(struct extattr_get_file_args *uap)
3779 {
3780 	char attrname[EXTATTR_MAXNAMELEN];
3781 	struct iovec aiov[UIO_SMALLIOV];
3782 	struct iovec *needfree;
3783 	struct nlookupdata nd;
3784 	struct iovec *iov;
3785 	struct vnode *vp;
3786 	struct uio auio;
3787 	u_int iovlen;
3788 	u_int cnt;
3789 	int error;
3790 	int i;
3791 
3792 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
3793 	if (error)
3794 		return (error);
3795 
3796 	vp = NULL;
3797 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3798 	if (error == 0)
3799 		error = nlookup(&nd);
3800 	if (error == 0)
3801 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
3802 	if (error) {
3803 		nlookup_done(&nd);
3804 		return (error);
3805 	}
3806 
3807 	iovlen = uap->iovcnt * sizeof (struct iovec);
3808 	needfree = NULL;
3809 	if (uap->iovcnt > UIO_SMALLIOV) {
3810 		if (uap->iovcnt > UIO_MAXIOV) {
3811 			error = EINVAL;
3812 			goto done;
3813 		}
3814 		MALLOC(iov, struct iovec *, iovlen, M_IOV, M_WAITOK);
3815 		needfree = iov;
3816 	} else {
3817 		iov = aiov;
3818 	}
3819 	auio.uio_iov = iov;
3820 	auio.uio_iovcnt = uap->iovcnt;
3821 	auio.uio_rw = UIO_READ;
3822 	auio.uio_segflg = UIO_USERSPACE;
3823 	auio.uio_td = nd.nl_td;
3824 	auio.uio_offset = 0;
3825 	if ((error = copyin(uap->iovp, iov, iovlen)))
3826 		goto done;
3827 	auio.uio_resid = 0;
3828 	for (i = 0; i < uap->iovcnt; i++) {
3829 		if (iov->iov_len > INT_MAX - auio.uio_resid) {
3830 			error = EINVAL;
3831 			goto done;
3832 		}
3833 		auio.uio_resid += iov->iov_len;
3834 		iov++;
3835 	}
3836 	cnt = auio.uio_resid;
3837 	error = VOP_GETEXTATTR(vp, attrname, &auio, nd.nl_cred);
3838 	cnt -= auio.uio_resid;
3839 	uap->sysmsg_result = cnt;
3840 done:
3841 	vput(vp);
3842 	nlookup_done(&nd);
3843 	if (needfree)
3844 		FREE(needfree, M_IOV);
3845 	return(error);
3846 }
3847 
3848 /*
3849  * Syscall to delete a named extended attribute from a file or directory.
3850  * Accepts attribute name.  The real work happens in VOP_SETEXTATTR().
3851  */
3852 int
3853 sys_extattr_delete_file(struct extattr_delete_file_args *uap)
3854 {
3855 	char attrname[EXTATTR_MAXNAMELEN];
3856 	struct nlookupdata nd;
3857 	struct vnode *vp;
3858 	int error;
3859 
3860 	error = copyin(uap->attrname, attrname, EXTATTR_MAXNAMELEN);
3861 	if (error)
3862 		return(error);
3863 
3864 	vp = NULL;
3865 	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
3866 	if (error == 0)
3867 		error = nlookup(&nd);
3868 	if (error == 0)
3869 		error = ncp_writechk(&nd.nl_nch);
3870 	if (error == 0)
3871 		error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
3872 	if (error) {
3873 		nlookup_done(&nd);
3874 		return (error);
3875 	}
3876 
3877 	error = VOP_SETEXTATTR(vp, attrname, NULL, nd.nl_cred);
3878 	vput(vp);
3879 	nlookup_done(&nd);
3880 	return(error);
3881 }
3882 
3883 /*
3884  * Determine if the mount is visible to the process.
3885  */
3886 static int
3887 chroot_visible_mnt(struct mount *mp, struct proc *p)
3888 {
3889 	struct nchandle nch;
3890 
3891 	/*
3892 	 * Traverse from the mount point upwards.  If we hit the process
3893 	 * root then the mount point is visible to the process.
3894 	 */
3895 	nch = mp->mnt_ncmountpt;
3896 	while (nch.ncp) {
3897 		if (nch.mount == p->p_fd->fd_nrdir.mount &&
3898 		    nch.ncp == p->p_fd->fd_nrdir.ncp) {
3899 			return(1);
3900 		}
3901 		if (nch.ncp == nch.mount->mnt_ncmountpt.ncp) {
3902 			nch = nch.mount->mnt_ncmounton;
3903 		} else {
3904 			nch.ncp = nch.ncp->nc_parent;
3905 		}
3906 	}
3907 
3908 	/*
3909 	 * If the mount point is not visible to the process, but the
3910 	 * process root is in a subdirectory of the mount, return
3911 	 * TRUE anyway.
3912 	 */
3913 	if (p->p_fd->fd_nrdir.mount == mp)
3914 		return(1);
3915 
3916 	return(0);
3917 }
3918 
3919