xref: /netbsd-src/sys/nfs/nfs_export.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06)
1 /*	$NetBSD: nfs_export.c,v 1.9 2006/01/05 12:21:00 yamt Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997, 1998, 2004, 2005 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9  * NASA Ames Research Center.
10  * This code is derived from software contributed to The NetBSD Foundation
11  * by Charles M. Hannum.
12  * This code is derived from software contributed to The NetBSD Foundation
13  * by Julio M. Merino Vidal.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  * 3. All advertising materials mentioning features or use of this software
24  *    must display the following acknowledgement:
25  *	This product includes software developed by the NetBSD
26  *	Foundation, Inc. and its contributors.
27  * 4. Neither the name of The NetBSD Foundation nor the names of its
28  *    contributors may be used to endorse or promote products derived
29  *    from this software without specific prior written permission.
30  *
31  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
32  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
33  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
34  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
35  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
36  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
37  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
38  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
39  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41  * POSSIBILITY OF SUCH DAMAGE.
42  */
43 
44 /*
45  * Copyright (c) 1989, 1993
46  *	The Regents of the University of California.  All rights reserved.
47  * (c) UNIX System Laboratories, Inc.
48  * All or some portions of this file are derived from material licensed
49  * to the University of California by American Telephone and Telegraph
50  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
51  * the permission of UNIX System Laboratories, Inc.
52  *
53  * Redistribution and use in source and binary forms, with or without
54  * modification, are permitted provided that the following conditions
55  * are met:
56  * 1. Redistributions of source code must retain the above copyright
57  *    notice, this list of conditions and the following disclaimer.
58  * 2. Redistributions in binary form must reproduce the above copyright
59  *    notice, this list of conditions and the following disclaimer in the
60  *    documentation and/or other materials provided with the distribution.
61  * 3. Neither the name of the University nor the names of its contributors
62  *    may be used to endorse or promote products derived from this software
63  *    without specific prior written permission.
64  *
65  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
66  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
67  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
68  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
69  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
70  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
71  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
72  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
73  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
74  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
75  * SUCH DAMAGE.
76  *
77  *	@(#)vfs_subr.c	8.13 (Berkeley) 4/18/94
78  */
79 
80 /*
81  * VFS exports list management.
82  */
83 
84 #include <sys/cdefs.h>
85 __KERNEL_RCSID(0, "$NetBSD: nfs_export.c,v 1.9 2006/01/05 12:21:00 yamt Exp $");
86 
87 #include "opt_compat_netbsd.h"
88 #include "opt_inet.h"
89 
90 #include <sys/param.h>
91 #include <sys/systm.h>
92 #include <sys/queue.h>
93 #include <sys/proc.h>
94 #include <sys/mount.h>
95 #include <sys/vnode.h>
96 #include <sys/namei.h>
97 #include <sys/errno.h>
98 #include <sys/malloc.h>
99 #include <sys/domain.h>
100 #include <sys/mbuf.h>
101 #include <sys/dirent.h>
102 #include <sys/socket.h>		/* XXX for AF_MAX */
103 
104 #include <net/radix.h>
105 
106 #include <netinet/in.h>
107 
108 #include <nfs/rpcv2.h>
109 #include <nfs/nfsproto.h>
110 #include <nfs/nfs.h>
111 #include <nfs/nfs_var.h>
112 
113 /*
114  * Network address lookup element.
115  */
116 struct netcred {
117 	struct	radix_node netc_rnodes[2];
118 	int	netc_refcnt;
119 	int	netc_exflags;
120 	struct	ucred netc_anon;
121 };
122 
123 /*
124  * Network export information.
125  */
126 struct netexport {
127 	CIRCLEQ_ENTRY(netexport) ne_list;
128 	struct mount *ne_mount;
129 	struct netcred ne_defexported;		      /* Default export */
130 	struct radix_node_head *ne_rtable[AF_MAX+1]; /* Individual exports */
131 };
132 CIRCLEQ_HEAD(, netexport) netexport_list =
133     CIRCLEQ_HEAD_INITIALIZER(netexport_list);
134 
135 /* Malloc type used by the mount<->netexport map. */
136 MALLOC_DEFINE(M_NFS_EXPORT, "nfs_export", "NFS export data");
137 
138 /* Publicly exported file system. */
139 struct nfs_public nfs_pub;
140 
141 /*
142  * Local prototypes.
143  */
144 static int init_exports(struct mount *, struct netexport **);
145 static int hang_addrlist(struct mount *, struct netexport *,
146     const struct export_args *);
147 static int sacheck(struct sockaddr *);
148 static int free_netcred(struct radix_node *, void *);
149 static void clear_exports(struct netexport *);
150 static int export(struct netexport *, const struct export_args *);
151 static int setpublicfs(struct mount *, struct netexport *,
152     const struct export_args *);
153 static struct netcred *netcred_lookup(struct netexport *, struct mbuf *);
154 static struct netexport *netexport_lookup(const struct mount *);
155 static struct netexport *netexport_lookup_byfsid(const fsid_t *);
156 static void netexport_insert(struct netexport *);
157 static void netexport_remove(struct netexport *);
158 static void netexport_wrlock(void);
159 static void netexport_wrunlock(void);
160 
161 /*
162  * PUBLIC INTERFACE
163  */
164 
165 /*
166  * Declare and initialize the file system export hooks.
167  */
168 static void nfs_export_unmount(struct mount *);
169 
170 struct vfs_hooks nfs_export_hooks = {
171 	nfs_export_unmount
172 };
173 VFS_HOOKS_ATTACH(nfs_export_hooks);
174 
175 /*
176  * VFS unmount hook for NFS exports.
177  *
178  * Releases NFS exports list resources if the given mount point has some.
179  * As allocation happens lazily, it may be that it doesn't has this
180  * information, although it theorically should.
181  */
182 static void
183 nfs_export_unmount(struct mount *mp)
184 {
185 	struct netexport *ne;
186 
187 	KASSERT(mp != NULL);
188 
189 	netexport_wrlock();
190 	ne = netexport_lookup(mp);
191 	if (ne == NULL) {
192 		netexport_wrunlock();
193 		return;
194 	}
195 
196 	KASSERT(mp->mnt_op->vfs_vptofh != NULL &&
197 	    mp->mnt_op->vfs_fhtovp != NULL);
198 
199 	if (mp->mnt_flag & MNT_EXPUBLIC) {
200 		setpublicfs(NULL, NULL, NULL);
201 	}
202 
203 	netexport_remove(ne);
204 	netexport_wrunlock();
205 	free(ne, M_NFS_EXPORT);
206 }
207 
208 /*
209  * Atomically set the NFS exports list of the given file system, replacing
210  * it with a new list of entries.
211  *
212  * Returns zero on success or an appropriate error code otherwise.
213  *
214  * Helper function for the nfssvc(2) system call (NFSSVC_SETEXPORTSLIST
215  * command).
216  */
217 int
218 mountd_set_exports_list(const struct mountd_exports_list *mel, struct lwp *l)
219 {
220 	int error;
221 #ifdef notyet
222 	/* XXX: See below to see the reason why this is disabled. */
223 	size_t i;
224 #endif
225 	struct mount *mp;
226 	struct netexport *ne;
227 	struct nameidata nd;
228 	struct vnode *vp;
229 	struct fid fid;
230 
231 	if (suser(l->l_proc->p_ucred, &l->l_proc->p_acflag) != 0)
232 		return EPERM;
233 
234 	/* Lookup the file system path. */
235 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE, mel->mel_path, l);
236 	error = namei(&nd);
237 	if (error != 0)
238 		return error;
239 	vp = nd.ni_vp;
240 	mp = vp->v_mount;
241 
242 	/* The selected file system may not support NFS exports, so ensure
243 	 * it does. */
244 	if (mp->mnt_op->vfs_vptofh == NULL || mp->mnt_op->vfs_fhtovp == NULL ||
245 	    VFS_VPTOFH(vp, &fid) != 0) {
246 		error = EOPNOTSUPP;
247 		goto out_locked;
248 	}
249 	KASSERT(mp->mnt_op->vfs_vptofh != NULL &&
250 	    mp->mnt_op->vfs_fhtovp != NULL);
251 
252 	/* Mark the file system busy. */
253 	error = vfs_busy(mp, LK_NOWAIT, NULL);
254 	if (error != 0)
255 		goto out_locked;
256 
257 	netexport_wrlock();
258 	ne = netexport_lookup(mp);
259 	if (ne == NULL) {
260 		error = init_exports(mp, &ne);
261 		if (error != 0) {
262 			goto out_locked2;
263 		}
264 	}
265 
266 	KASSERT(ne != NULL);
267 	KASSERT(ne->ne_mount == mp);
268 
269 	/*
270 	 * XXX: The part marked as 'notyet' works fine from the kernel's
271 	 * point of view, in the sense that it is able to atomically update
272 	 * the complete exports list for a file system.  However, supporting
273 	 * this in mountd(8) requires a lot of work; so, for now, keep the
274 	 * old behavior of updating a single entry per call.
275 	 *
276 	 * When mountd(8) is fixed, just remove the second branch of this
277 	 * preprocessor conditional and enable the first one.
278 	 */
279 #ifdef notyet
280 	clear_exports(ne);
281 	for (i = 0; error == 0 && i < mel->mel_nexports; i++)
282 		error = export(ne, &mel->mel_exports[i]);
283 #else
284 	if (mel->mel_nexports == 0)
285 		clear_exports(ne);
286 	else if (mel->mel_nexports == 1)
287 		error = export(ne, &mel->mel_exports[0]);
288 	else {
289 		printf("mountd_set_exports_list: Cannot set more than one "
290 		    "entry at once (unimplemented)\n");
291 		error = EOPNOTSUPP;
292 	}
293 #endif
294 
295 out_locked2:
296 	netexport_wrunlock();
297 	vfs_unbusy(mp);
298 
299 out_locked:
300 	vput(vp);
301 
302 	return error;
303 }
304 
305 static void
306 netexport_insert(struct netexport *ne)
307 {
308 
309 	CIRCLEQ_INSERT_HEAD(&netexport_list, ne, ne_list);
310 }
311 
312 static void
313 netexport_remove(struct netexport *ne)
314 {
315 
316 	CIRCLEQ_REMOVE(&netexport_list, ne, ne_list);
317 }
318 
319 static struct netexport *
320 netexport_lookup(const struct mount *mp)
321 {
322 	struct netexport *ne;
323 
324 	CIRCLEQ_FOREACH(ne, &netexport_list, ne_list) {
325 		if (ne->ne_mount == mp) {
326 			goto done;
327 		}
328 	}
329 	ne = NULL;
330 done:
331 	return ne;
332 }
333 
334 static struct netexport *
335 netexport_lookup_byfsid(const fsid_t *fsid)
336 {
337 	struct netexport *ne;
338 
339 	CIRCLEQ_FOREACH(ne, &netexport_list, ne_list) {
340 		const struct mount *mp = ne->ne_mount;
341 
342 		if (mp->mnt_stat.f_fsidx.__fsid_val[0] == fsid->__fsid_val[0] &&
343 		    mp->mnt_stat.f_fsidx.__fsid_val[1] == fsid->__fsid_val[1]) {
344 			goto done;
345 		}
346 	}
347 	ne = NULL;
348 done:
349 
350 	return ne;
351 }
352 
353 /*
354  * Check if the file system specified by the 'mp' mount structure is
355  * exported to a client with 'anon' anonymous credentials.  The 'mb'
356  * argument is an mbuf containing the network address of the client.
357  * The return parameters for the export flags for the client are returned
358  * in the address specified by 'wh'.
359  *
360  * This function is used exclusively by the NFS server.  It is generally
361  * invoked before VFS_FHTOVP to validate that client has access to the
362  * file system.
363  */
364 
365 int
366 netexport_check(const fsid_t *fsid, struct mbuf *mb, struct mount **mpp,
367     int *wh, struct ucred **anon)
368 {
369 	struct netexport *ne;
370 	struct netcred *np;
371 
372 	ne = netexport_lookup_byfsid(fsid);
373 	if (ne == NULL) {
374 		return EACCES;
375 	}
376 	np = netcred_lookup(ne, mb);
377 	if (np == NULL) {
378 		return EACCES;
379 	}
380 
381 	*mpp = ne->ne_mount;
382 	*wh = np->netc_exflags;
383 	*anon = &np->netc_anon;
384 
385 	return 0;
386 }
387 
388 #ifdef COMPAT_30
389 /*
390  * Handles legacy export requests.  In this case, the export information
391  * is hardcoded in a specific place of the mount arguments structure (given
392  * in data); the request for an update is given through the fspec field
393  * (also in a known location), which must be a null pointer.
394  *
395  * Returns EJUSTRETURN if the given command was not a export request.
396  * Otherwise, returns 0 on success or an appropriate error code otherwise.
397  */
398 int
399 nfs_update_exports_30(struct mount *mp, const char *path, void *data,
400     struct lwp *l)
401 {
402 	int error;
403 	struct {
404 		const char *fspec;
405 		struct export_args30 eargs;
406 	} args;
407 	struct mountd_exports_list mel;
408 
409 	mel.mel_path = path;
410 
411 	error = copyin(data, &args, sizeof(args));
412 	if (error != 0)
413 		return EJUSTRETURN;
414 
415 	if (args.fspec != NULL)
416 		return EJUSTRETURN;
417 
418 	if (args.eargs.ex_flags & 0x00020000) {
419 		/* Request to delete exports.  The mask above holds the
420 		 * value that used to be in MNT_DELEXPORT. */
421 		mel.mel_nexports = 0;
422 	} else {
423 		struct export_args eargs;
424 
425 		/* The following assumes export_args has not changed since
426 		 * export_args30. */
427 		memcpy(&eargs, &args.eargs, sizeof(struct export_args));
428 
429 		mel.mel_nexports = 1;
430 		mel.mel_exports = &eargs;
431 	}
432 
433 	return mountd_set_exports_list(&mel, l);
434 }
435 #endif
436 
437 /*
438  * INTERNAL FUNCTIONS
439  */
440 
441 /*
442  * Initializes NFS exports for the file system given in 'mp' if it supports
443  * file handles; this is determined by checking whether mp's vfs_vptofh and
444  * vfs_fhtovp operations are NULL or not.
445  *
446  * If successful, returns 0 and sets *mnpp to the address of the new
447  * mount_netexport_pair item; otherwise returns and appropriate error code
448  * and *mnpp remains unmodified.
449  */
450 static int
451 init_exports(struct mount *mp, struct netexport **nep)
452 {
453 	int error;
454 	struct export_args ea;
455 	struct netexport *ne;
456 
457 	KASSERT(mp != NULL);
458 	KASSERT(mp->mnt_op->vfs_vptofh != NULL &&
459 	    mp->mnt_op->vfs_fhtovp != NULL);
460 
461 	/* Ensure that we do not already have this mount point. */
462 	KASSERT(netexport_lookup(mp) == NULL);
463 
464 	ne = malloc(sizeof(*ne), M_NFS_EXPORT, M_WAITOK | M_ZERO);
465 	ne->ne_mount = mp;
466 
467 	/* Set the default export entry.  Handled internally by export upon
468 	 * first call. */
469 	memset(&ea, 0, sizeof(ea));
470 	ea.ex_root = -2;
471 	if (mp->mnt_flag & MNT_RDONLY)
472 		ea.ex_flags |= MNT_EXRDONLY;
473 	error = export(ne, &ea);
474 	if (error != 0) {
475 		free(ne, M_NFS_EXPORT);
476 	} else {
477 		netexport_insert(ne);
478 		*nep = ne;
479 	}
480 
481 	return error;
482 }
483 
484 /*
485  * Build hash lists of net addresses and hang them off the mount point.
486  * Called by export() to set up a new entry in the lists of export
487  * addresses.
488  */
489 static int
490 hang_addrlist(struct mount *mp, struct netexport *nep,
491     const struct export_args *argp)
492 {
493 	int error, i;
494 	struct netcred *np, *enp;
495 	struct radix_node_head *rnh;
496 	struct sockaddr *saddr, *smask;
497 	struct domain *dom;
498 
499 	smask = NULL;
500 
501 	if (argp->ex_addrlen == 0) {
502 		if (mp->mnt_flag & MNT_DEFEXPORTED)
503 			return EPERM;
504 		np = &nep->ne_defexported;
505 		np->netc_exflags = argp->ex_flags;
506 		crcvt(&np->netc_anon, &argp->ex_anon);
507 		np->netc_anon.cr_ref = 1;
508 		mp->mnt_flag |= MNT_DEFEXPORTED;
509 		return 0;
510 	}
511 
512 	if (argp->ex_addrlen > MLEN || argp->ex_masklen > MLEN)
513 		return EINVAL;
514 
515 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
516 	np = malloc(i, M_NETADDR, M_WAITOK | M_ZERO);
517 	saddr = (struct sockaddr *)(np + 1);
518 	error = copyin(argp->ex_addr, saddr, argp->ex_addrlen);
519 	if (error)
520 		goto out;
521 	if (saddr->sa_len > argp->ex_addrlen)
522 		saddr->sa_len = argp->ex_addrlen;
523 	if (sacheck(saddr) == -1)
524 		return EINVAL;
525 	if (argp->ex_masklen) {
526 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
527 		error = copyin(argp->ex_mask, smask, argp->ex_masklen);
528 		if (error)
529 			goto out;
530 		if (smask->sa_len > argp->ex_masklen)
531 			smask->sa_len = argp->ex_masklen;
532 		if (smask->sa_family != saddr->sa_family)
533 			return EINVAL;
534 		if (sacheck(smask) == -1)
535 			return EINVAL;
536 	}
537 	i = saddr->sa_family;
538 	if ((rnh = nep->ne_rtable[i]) == 0) {
539 		/*
540 		 * Seems silly to initialize every AF when most are not
541 		 * used, do so on demand here
542 		 */
543 		DOMAIN_FOREACH(dom) {
544 			if (dom->dom_family == i && dom->dom_rtattach) {
545 				dom->dom_rtattach((void **)&nep->ne_rtable[i],
546 					dom->dom_rtoffset);
547 				break;
548 			}
549 		}
550 		if ((rnh = nep->ne_rtable[i]) == 0) {
551 			error = ENOBUFS;
552 			goto out;
553 		}
554 	}
555 
556 	enp = (struct netcred *)(*rnh->rnh_addaddr)(saddr, smask, rnh,
557 	    np->netc_rnodes);
558 	if (enp != np) {
559 		if (enp == NULL) {
560 			enp = (struct netcred *)(*rnh->rnh_lookup)(saddr,
561 			    smask, rnh);
562 			if (enp == NULL) {
563 				error = EPERM;
564 				goto out;
565 			}
566 		} else
567 			enp->netc_refcnt++;
568 
569 		goto check;
570 	} else
571 		enp->netc_refcnt = 1;
572 
573 	np->netc_exflags = argp->ex_flags;
574 	crcvt(&np->netc_anon, &argp->ex_anon);
575 	np->netc_anon.cr_ref = 1;
576 	return 0;
577 check:
578 	if (enp->netc_exflags != argp->ex_flags ||
579 	    crcmp(&enp->netc_anon, &argp->ex_anon) != 0)
580 		error = EPERM;
581 	else
582 		error = 0;
583 out:
584 	free(np, M_NETADDR);
585 	return error;
586 }
587 
588 /*
589  * Ensure that the address stored in 'sa' is valid.
590  * Returns zero on success, otherwise -1.
591  */
592 static int
593 sacheck(struct sockaddr *sa)
594 {
595 
596 	switch (sa->sa_family) {
597 #ifdef INET
598 	case AF_INET: {
599 		struct sockaddr_in *sin = (struct sockaddr_in *)sa;
600 		char *p = (char *)sin->sin_zero;
601 		size_t i;
602 
603 		if (sin->sin_len != sizeof(*sin))
604 			return -1;
605 		if (sin->sin_port != 0)
606 			return -1;
607 		for (i = 0; i < sizeof(sin->sin_zero); i++)
608 			if (*p++ != '\0')
609 				return -1;
610 		return 0;
611 	}
612 #endif
613 #ifdef INET6
614 	case AF_INET6: {
615 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
616 
617 		if (sin6->sin6_len != sizeof(*sin6))
618 			return -1;
619 		if (sin6->sin6_port != 0)
620 			return -1;
621 		return 0;
622 	}
623 #endif
624 	default:
625 		return -1;
626 	}
627 }
628 
629 /*
630  * Free the netcred object pointed to by the 'rn' radix node.
631  * 'w' holds a pointer to the radix tree head.
632  */
633 static int
634 free_netcred(struct radix_node *rn, void *w)
635 {
636 	struct radix_node_head *rnh = (struct radix_node_head *)w;
637 	struct netcred *np = (struct netcred *)(void *)rn;
638 
639 	(*rnh->rnh_deladdr)(rn->rn_key, rn->rn_mask, rnh);
640 	if (--(np->netc_refcnt) <= 0)
641 		free(np, M_NETADDR);
642 	return 0;
643 }
644 
645 /*
646  * Clears the exports list for a given file system.
647  */
648 static void
649 clear_exports(struct netexport *ne)
650 {
651 	struct radix_node_head *rnh;
652 	struct mount *mp = ne->ne_mount;
653 	int i;
654 
655 	if (mp->mnt_flag & MNT_EXPUBLIC) {
656 		setpublicfs(NULL, NULL, NULL);
657 		mp->mnt_flag &= ~MNT_EXPUBLIC;
658 	}
659 
660 	for (i = 0; i <= AF_MAX; i++) {
661 		if ((rnh = ne->ne_rtable[i]) != NULL) {
662 			(*rnh->rnh_walktree)(rnh, free_netcred, rnh);
663 			free(rnh, M_RTABLE);
664 			ne->ne_rtable[i] = NULL;
665 		}
666 	}
667 
668 	mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
669 }
670 
671 /*
672  * Add a new export entry (described by an export_args structure) to the
673  * given file system.
674  */
675 static int
676 export(struct netexport *nep, const struct export_args *argp)
677 {
678 	struct mount *mp = nep->ne_mount;
679 	int error;
680 
681 	if (argp->ex_flags & MNT_EXPORTED) {
682 		if (argp->ex_flags & MNT_EXPUBLIC) {
683 			if ((error = setpublicfs(mp, nep, argp)) != 0)
684 				return error;
685 			mp->mnt_flag |= MNT_EXPUBLIC;
686 		}
687 		if ((error = hang_addrlist(mp, nep, argp)) != 0)
688 			return error;
689 		mp->mnt_flag |= MNT_EXPORTED;
690 	}
691 	return 0;
692 }
693 
694 /*
695  * Set the publicly exported filesystem (WebNFS).  Currently, only
696  * one public filesystem is possible in the spec (RFC 2054 and 2055)
697  */
698 static int
699 setpublicfs(struct mount *mp, struct netexport *nep,
700     const struct export_args *argp)
701 {
702 	char *cp;
703 	int error;
704 	struct vnode *rvp;
705 
706 	/*
707 	 * mp == NULL -> invalidate the current info, the FS is
708 	 * no longer exported. May be called from either export
709 	 * or unmount, so check if it hasn't already been done.
710 	 */
711 	if (mp == NULL) {
712 		if (nfs_pub.np_valid) {
713 			nfs_pub.np_valid = 0;
714 			if (nfs_pub.np_index != NULL) {
715 				FREE(nfs_pub.np_index, M_TEMP);
716 				nfs_pub.np_index = NULL;
717 			}
718 		}
719 		return 0;
720 	}
721 
722 	/*
723 	 * Only one allowed at a time.
724 	 */
725 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
726 		return EBUSY;
727 
728 	/*
729 	 * Get real filehandle for root of exported FS.
730 	 */
731 	memset((caddr_t)&nfs_pub.np_handle, 0, sizeof(nfs_pub.np_handle));
732 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsidx;
733 
734 	if ((error = VFS_ROOT(mp, &rvp)))
735 		return error;
736 
737 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
738 		return error;
739 
740 	vput(rvp);
741 
742 	/*
743 	 * If an indexfile was specified, pull it in.
744 	 */
745 	if (argp->ex_indexfile != NULL) {
746 		MALLOC(nfs_pub.np_index, char *, MAXNAMLEN + 1, M_TEMP,
747 		    M_WAITOK);
748 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
749 		    MAXNAMLEN, (size_t *)0);
750 		if (!error) {
751 			/*
752 			 * Check for illegal filenames.
753 			 */
754 			for (cp = nfs_pub.np_index; *cp; cp++) {
755 				if (*cp == '/') {
756 					error = EINVAL;
757 					break;
758 				}
759 			}
760 		}
761 		if (error) {
762 			FREE(nfs_pub.np_index, M_TEMP);
763 			return error;
764 		}
765 	}
766 
767 	nfs_pub.np_mount = mp;
768 	nfs_pub.np_valid = 1;
769 	return 0;
770 }
771 
772 /*
773  * Lookup an export entry in the exports list that matches the address
774  * stored in 'nam'.  If no entry is found, the default one is used instead
775  * (if available).
776  */
777 static struct netcred *
778 netcred_lookup(struct netexport *ne, struct mbuf *nam)
779 {
780 	struct netcred *np;
781 	struct radix_node_head *rnh;
782 	struct sockaddr *saddr;
783 
784 	if ((ne->ne_mount->mnt_flag & MNT_EXPORTED) == 0) {
785 		return NULL;
786 	}
787 
788 	/*
789 	 * Lookup in the export list first.
790 	 */
791 	np = NULL;
792 	if (nam != NULL) {
793 		saddr = mtod(nam, struct sockaddr *);
794 		rnh = ne->ne_rtable[saddr->sa_family];
795 		if (rnh != NULL) {
796 			np = (struct netcred *)
797 				(*rnh->rnh_matchaddr)((caddr_t)saddr,
798 						      rnh);
799 			if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
800 				np = NULL;
801 		}
802 	}
803 	/*
804 	 * If no address match, use the default if it exists.
805 	 */
806 	if (np == NULL && ne->ne_mount->mnt_flag & MNT_DEFEXPORTED)
807 		np = &ne->ne_defexported;
808 
809 	return np;
810 }
811 
812 static struct lock netexport_lock = LOCK_INITIALIZER(PVFS, "netexp", 0, 0);
813 
814 void
815 netexport_rdlock(void)
816 {
817 
818 	lockmgr(&netexport_lock, LK_SHARED, NULL);
819 }
820 
821 void
822 netexport_rdunlock(void)
823 {
824 
825 	lockmgr(&netexport_lock, LK_RELEASE, NULL);
826 }
827 
828 static void
829 netexport_wrlock(void)
830 {
831 
832 	lockmgr(&netexport_lock, LK_EXCLUSIVE, NULL);
833 }
834 
835 static void
836 netexport_wrunlock(void)
837 {
838 
839 	lockmgr(&netexport_lock, LK_RELEASE, NULL);
840 }
841