1/*	$NetBSD: umap_vfsops.c,v 1.86.20.1 2014/04/21 10:17:48 bouyer Exp $	*/
2
3/*
4 * Copyright (c) 1992, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software donated to Berkeley by
8 * the UCLA Ficus project.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 *	from: @(#)null_vfsops.c       1.5 (Berkeley) 7/10/92
35 *	@(#)umap_vfsops.c	8.8 (Berkeley) 5/14/95
36 */
37
38/*
39 * Umap Layer
40 * (See mount_umap(8) for a description of this layer.)
41 */
42
43#include <sys/cdefs.h>
44__KERNEL_RCSID(0, "$NetBSD: umap_vfsops.c,v 1.86.20.1 2014/04/21 10:17:48 bouyer Exp $");
45
46#include <sys/param.h>
47#include <sys/systm.h>
48#include <sys/sysctl.h>
49#include <sys/proc.h>
50#include <sys/time.h>
51#include <sys/vnode.h>
52#include <sys/mount.h>
53#include <sys/namei.h>
54#include <sys/malloc.h>
55#include <sys/kauth.h>
56#include <sys/module.h>
57
58#include <miscfs/umapfs/umap.h>
59#include <miscfs/genfs/layer_extern.h>
60
61MODULE(MODULE_CLASS_VFS, umap, "layerfs");
62
63VFS_PROTOS(umapfs);
64
65static struct sysctllog *umapfs_sysctl_log;
66
67/*
68 * Mount umap layer
69 */
70int
71umapfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
72{
73	struct lwp *l = curlwp;
74	struct pathbuf *pb;
75	struct nameidata nd;
76	struct umap_args *args = data;
77	struct vnode *lowerrootvp, *vp;
78	struct umap_mount *amp;
79	int error;
80#ifdef UMAPFS_DIAGNOSTIC
81	int i;
82#endif
83
84	if (args == NULL)
85		return EINVAL;
86	if (*data_len < sizeof *args)
87		return EINVAL;
88
89	if (mp->mnt_flag & MNT_GETARGS) {
90		amp = MOUNTTOUMAPMOUNT(mp);
91		if (amp == NULL)
92			return EIO;
93		args->la.target = NULL;
94		args->nentries = amp->info_nentries;
95		args->gnentries = amp->info_gnentries;
96		*data_len = sizeof *args;
97		return 0;
98	}
99
100	/* only for root */
101	if ((error = kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
102	    NULL)) != 0)
103		return error;
104
105#ifdef UMAPFS_DIAGNOSTIC
106	printf("umapfs_mount(mp = %p)\n", mp);
107#endif
108
109	/*
110	 * Update is not supported
111	 */
112	if (mp->mnt_flag & MNT_UPDATE)
113		return EOPNOTSUPP;
114
115	/*
116	 * Find lower node
117	 */
118	error = pathbuf_copyin(args->umap_target, &pb);
119	if (error) {
120		return error;
121	}
122	NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, pb);
123	if ((error = namei(&nd)) != 0) {
124		pathbuf_destroy(pb);
125		return error;
126	}
127
128	/*
129	 * Sanity check on lower vnode
130	 */
131	lowerrootvp = nd.ni_vp;
132	pathbuf_destroy(pb);
133#ifdef UMAPFS_DIAGNOSTIC
134	printf("vp = %p, check for VDIR...\n", lowerrootvp);
135#endif
136
137	if (lowerrootvp->v_type != VDIR) {
138		vput(lowerrootvp);
139		return (EINVAL);
140	}
141
142#ifdef UMAPFS_DIAGNOSTIC
143	printf("mp = %p\n", mp);
144#endif
145
146	amp = (struct umap_mount *) malloc(sizeof(struct umap_mount),
147				M_UFSMNT, M_WAITOK);	/* XXX */
148	memset(amp, 0, sizeof(struct umap_mount));
149
150	mp->mnt_data = amp;
151	amp->umapm_vfs = lowerrootvp->v_mount;
152	if (amp->umapm_vfs->mnt_flag & MNT_LOCAL)
153		mp->mnt_flag |= MNT_LOCAL;
154
155	/*
156	 * Now copy in the number of entries and maps for umap mapping.
157	 */
158	if (args->nentries < 0 || args->nentries > MAPFILEENTRIES ||
159	    args->gnentries < 0 || args->gnentries > GMAPFILEENTRIES) {
160		vput(lowerrootvp);
161		return (EINVAL);
162	}
163
164	amp->info_nentries = args->nentries;
165	amp->info_gnentries = args->gnentries;
166	error = copyin(args->mapdata, amp->info_mapdata,
167	    2*sizeof(u_long)*args->nentries);
168	if (error) {
169		vput(lowerrootvp);
170		return (error);
171	}
172
173#ifdef UMAPFS_DIAGNOSTIC
174	printf("umap_mount:nentries %d\n",args->nentries);
175	for (i = 0; i < args->nentries; i++)
176		printf("   %ld maps to %ld\n", amp->info_mapdata[i][0],
177	 	    amp->info_mapdata[i][1]);
178#endif
179
180	error = copyin(args->gmapdata, amp->info_gmapdata,
181	    2*sizeof(u_long)*args->gnentries);
182	if (error) {
183		vput(lowerrootvp);
184		return (error);
185	}
186
187#ifdef UMAPFS_DIAGNOSTIC
188	printf("umap_mount:gnentries %d\n",args->gnentries);
189	for (i = 0; i < args->gnentries; i++)
190		printf("\tgroup %ld maps to %ld\n",
191		    amp->info_gmapdata[i][0],
192	 	    amp->info_gmapdata[i][1]);
193#endif
194
195	/*
196	 * Make sure the mount point's sufficiently initialized
197	 * that the node create call will work.
198	 */
199	vfs_getnewfsid(mp);
200	amp->umapm_size = sizeof(struct umap_node);
201	amp->umapm_tag = VT_UMAP;
202	amp->umapm_bypass = umap_bypass;
203	amp->umapm_alloc = layer_node_alloc;	/* the default alloc is fine */
204	amp->umapm_vnodeop_p = umap_vnodeop_p;
205	mutex_init(&amp->umapm_hashlock, MUTEX_DEFAULT, IPL_NONE);
206	amp->umapm_node_hashtbl = hashinit(NUMAPNODECACHE, HASH_LIST, true,
207	    &amp->umapm_node_hash);
208
209
210	/*
211	 * fix up umap node for root vnode.
212	 */
213	error = layer_node_create(mp, lowerrootvp, &vp);
214	/*
215	 * Make sure the node alias worked
216	 */
217	if (error) {
218		vput(lowerrootvp);
219		hashdone(amp->umapm_node_hashtbl, HASH_LIST,
220		    amp->umapm_node_hash);
221		free(amp, M_UFSMNT);	/* XXX */
222		return (error);
223	}
224	/*
225	 * Unlock the node (either the lower or the alias)
226	 */
227	vp->v_vflag |= VV_ROOT;
228	VOP_UNLOCK(vp);
229
230	/*
231	 * Keep a held reference to the root vnode.
232	 * It is vrele'd in umapfs_unmount.
233	 */
234	amp->umapm_rootvp = vp;
235
236	error = set_statvfs_info(path, UIO_USERSPACE, args->umap_target,
237	    UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
238#ifdef UMAPFS_DIAGNOSTIC
239	printf("umapfs_mount: lower %s, alias at %s\n",
240		mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
241#endif
242	return error;
243}
244
245/*
246 * Free reference to umap layer
247 */
248int
249umapfs_unmount(struct mount *mp, int mntflags)
250{
251	struct umap_mount *amp = MOUNTTOUMAPMOUNT(mp);
252	struct vnode *rtvp = amp->umapm_rootvp;
253	int error;
254	int flags = 0;
255
256#ifdef UMAPFS_DIAGNOSTIC
257	printf("umapfs_unmount(mp = %p)\n", mp);
258#endif
259
260	if (mntflags & MNT_FORCE)
261		flags |= FORCECLOSE;
262
263	if (rtvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0)
264		return (EBUSY);
265	if ((error = vflush(mp, rtvp, flags)) != 0)
266		return (error);
267
268#ifdef UMAPFS_DIAGNOSTIC
269	vprint("alias root of lower", rtvp);
270#endif
271	/*
272	 * Blow it away for future re-use
273	 */
274	vgone(rtvp);
275	/*
276	 * Finally, throw away the umap_mount structure
277	 */
278	mutex_destroy(&amp->umapm_hashlock);
279	hashdone(amp->umapm_node_hashtbl, HASH_LIST, amp->umapm_node_hash);
280	free(amp, M_UFSMNT);	/* XXX */
281	mp->mnt_data = NULL;
282	return (0);
283}
284
285extern const struct vnodeopv_desc umapfs_vnodeop_opv_desc;
286
287const struct vnodeopv_desc * const umapfs_vnodeopv_descs[] = {
288	&umapfs_vnodeop_opv_desc,
289	NULL,
290};
291
292struct vfsops umapfs_vfsops = {
293	MOUNT_UMAP,
294	sizeof (struct umap_args),
295	umapfs_mount,
296	layerfs_start,
297	umapfs_unmount,
298	layerfs_root,
299	layerfs_quotactl,
300	layerfs_statvfs,
301	layerfs_sync,
302	layerfs_vget,
303	layerfs_fhtovp,
304	layerfs_vptofh,
305	layerfs_init,
306	NULL,
307	layerfs_done,
308	NULL,				/* vfs_mountroot */
309	layerfs_snapshot,
310	vfs_stdextattrctl,
311	(void *)eopnotsupp,		/* vfs_suspendctl */
312	layerfs_renamelock_enter,
313	layerfs_renamelock_exit,
314	(void *)eopnotsupp,
315	umapfs_vnodeopv_descs,
316	0,				/* vfs_refcount */
317	{ NULL, NULL },
318};
319
320static int
321umap_modcmd(modcmd_t cmd, void *arg)
322{
323	int error;
324
325	switch (cmd) {
326	case MODULE_CMD_INIT:
327		error = vfs_attach(&umapfs_vfsops);
328		if (error != 0)
329			break;
330		sysctl_createv(&umapfs_sysctl_log, 0, NULL, NULL,
331			       CTLFLAG_PERMANENT,
332			       CTLTYPE_NODE, "vfs", NULL,
333			       NULL, 0, NULL, 0,
334			       CTL_VFS, CTL_EOL);
335		sysctl_createv(&umapfs_sysctl_log, 0, NULL, NULL,
336			       CTLFLAG_PERMANENT,
337			       CTLTYPE_NODE, "umap",
338			       SYSCTL_DESCR("UID/GID remapping file system"),
339			       NULL, 0, NULL, 0,
340			       CTL_VFS, 10, CTL_EOL);
341		/*
342		 * XXX the "10" above could be dynamic, thereby eliminating
343		 * one more instance of the "number to vfs" mapping problem,
344		 * but "10" is the order as taken from sys/mount.h
345		 */
346		break;
347	case MODULE_CMD_FINI:
348		error = vfs_detach(&umapfs_vfsops);
349		if (error != 0)
350			break;
351		sysctl_teardown(&umapfs_sysctl_log);
352		break;
353	default:
354		error = ENOTTY;
355		break;
356	}
357
358	return (error);
359}
360