1/* $NetBSD: umap_vfsops.c,v 1.95 2014/11/09 18:08:07 maxv 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 1.95 2014/11/09 18:08:07 maxv 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/kauth.h>
55#include <sys/module.h>
56
57#include <miscfs/umapfs/umap.h>
58#include <miscfs/genfs/layer_extern.h>
59
60MODULE(MODULE_CLASS_VFS, umap, "layerfs");
61
62VFS_PROTOS(umapfs);
63
64static struct sysctllog *umapfs_sysctl_log;
65
66/*
67 * Mount umap layer
68 */
69int
70umapfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
71{
72 struct lwp *l = curlwp;
73 struct pathbuf *pb;
74 struct nameidata nd;
75 struct umap_args *args = data;
76 struct vnode *lowerrootvp, *vp;
77 struct umap_mount *amp;
78 int error;
79#ifdef UMAPFS_DIAGNOSTIC
80 int i;
81#endif
82
83 if (args == NULL)
84 return EINVAL;
85 if (*data_len < sizeof *args)
86 return EINVAL;
87
88 if (mp->mnt_flag & MNT_GETARGS) {
89 amp = MOUNTTOUMAPMOUNT(mp);
90 if (amp == NULL)
91 return EIO;
92 args->la.target = NULL;
93 args->nentries = amp->info_nentries;
94 args->gnentries = amp->info_gnentries;
95 *data_len = sizeof *args;
96 return 0;
97 }
98
99 /* only for root */
100 error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_MOUNT,
101 KAUTH_REQ_SYSTEM_MOUNT_UMAP, NULL, NULL, NULL);
102 if (error)
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 = kmem_zalloc(sizeof(struct umap_mount), KM_SLEEP);
147 mp->mnt_data = amp;
148 amp->umapm_vfs = lowerrootvp->v_mount;
149 if (amp->umapm_vfs->mnt_flag & MNT_LOCAL)
150 mp->mnt_flag |= MNT_LOCAL;
151
152 /*
153 * Now copy in the number of entries and maps for umap mapping.
154 */
155 if (args->nentries < 0 || args->nentries > MAPFILEENTRIES ||
156 args->gnentries < 0 || args->gnentries > GMAPFILEENTRIES) {
157 vput(lowerrootvp);
158 return (EINVAL);
159 }
160
161 amp->info_nentries = args->nentries;
162 amp->info_gnentries = args->gnentries;
163 error = copyin(args->mapdata, amp->info_mapdata,
164 2*sizeof(u_long)*args->nentries);
165 if (error) {
166 vput(lowerrootvp);
167 return (error);
168 }
169
170#ifdef UMAPFS_DIAGNOSTIC
171 printf("umap_mount:nentries %d\n",args->nentries);
172 for (i = 0; i < args->nentries; i++)
173 printf(" %ld maps to %ld\n", amp->info_mapdata[i][0],
174 amp->info_mapdata[i][1]);
175#endif
176
177 error = copyin(args->gmapdata, amp->info_gmapdata,
178 2*sizeof(u_long)*args->gnentries);
179 if (error) {
180 vput(lowerrootvp);
181 return (error);
182 }
183
184#ifdef UMAPFS_DIAGNOSTIC
185 printf("umap_mount:gnentries %d\n",args->gnentries);
186 for (i = 0; i < args->gnentries; i++)
187 printf("\tgroup %ld maps to %ld\n",
188 amp->info_gmapdata[i][0],
189 amp->info_gmapdata[i][1]);
190#endif
191
192 /*
193 * Make sure the mount point's sufficiently initialized
194 * that the node create call will work.
195 */
196 vfs_getnewfsid(mp);
197 amp->umapm_size = sizeof(struct umap_node);
198 amp->umapm_tag = VT_UMAP;
199 amp->umapm_bypass = umap_bypass;
200 amp->umapm_vnodeop_p = umap_vnodeop_p;
201
202 /*
203 * fix up umap node for root vnode.
204 */
205 VOP_UNLOCK(lowerrootvp);
206 error = layer_node_create(mp, lowerrootvp, &vp);
207 /*
208 * Make sure the node alias worked
209 */
210 if (error) {
211 vrele(lowerrootvp);
212 kmem_free(amp, sizeof(struct umap_mount));
213 return error;
214 }
215
216 /*
217 * Keep a held reference to the root vnode.
218 * It is vrele'd in umapfs_unmount.
219 */
220 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
221 vp->v_vflag |= VV_ROOT;
222 amp->umapm_rootvp = vp;
223 VOP_UNLOCK(vp);
224
225 error = set_statvfs_info(path, UIO_USERSPACE, args->umap_target,
226 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
227#ifdef UMAPFS_DIAGNOSTIC
228 printf("umapfs_mount: lower %s, alias at %s\n",
229 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
230#endif
231 return error;
232}
233
234/*
235 * Free reference to umap layer
236 */
237int
238umapfs_unmount(struct mount *mp, int mntflags)
239{
240 struct umap_mount *amp = MOUNTTOUMAPMOUNT(mp);
241 struct vnode *rtvp = amp->umapm_rootvp;
242 int error;
243 int flags = 0;
244
245#ifdef UMAPFS_DIAGNOSTIC
246 printf("umapfs_unmount(mp = %p)\n", mp);
247#endif
248
249 if (mntflags & MNT_FORCE)
250 flags |= FORCECLOSE;
251
252 if (rtvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0)
253 return (EBUSY);
254 if ((error = vflush(mp, rtvp, flags)) != 0)
255 return (error);
256
257#ifdef UMAPFS_DIAGNOSTIC
258 vprint("alias root of lower", rtvp);
259#endif
260 /*
261 * Blow it away for future re-use
262 */
263 vgone(rtvp);
264 /*
265 * Finally, throw away the umap_mount structure
266 */
267 kmem_free(amp, sizeof(struct umap_mount));
268 mp->mnt_data = NULL;
269 return 0;
270}
271
272extern const struct vnodeopv_desc umapfs_vnodeop_opv_desc;
273
274const struct vnodeopv_desc * const umapfs_vnodeopv_descs[] = {
275 &umapfs_vnodeop_opv_desc,
276 NULL,
277};
278
279struct vfsops umapfs_vfsops = {
280 .vfs_name = MOUNT_UMAP,
281 .vfs_min_mount_data = sizeof (struct umap_args),
282 .vfs_mount = umapfs_mount,
283 .vfs_start = layerfs_start,
284 .vfs_unmount = umapfs_unmount,
285 .vfs_root = layerfs_root,
286 .vfs_quotactl = layerfs_quotactl,
287 .vfs_statvfs = layerfs_statvfs,
288 .vfs_sync = layerfs_sync,
289 .vfs_loadvnode = layerfs_loadvnode,
290 .vfs_vget = layerfs_vget,
291 .vfs_fhtovp = layerfs_fhtovp,
292 .vfs_vptofh = layerfs_vptofh,
293 .vfs_init = layerfs_init,
294 .vfs_done = layerfs_done,
295 .vfs_snapshot = layerfs_snapshot,
296 .vfs_extattrctl = vfs_stdextattrctl,
297 .vfs_suspendctl = (void *)eopnotsupp,
298 .vfs_renamelock_enter = layerfs_renamelock_enter,
299 .vfs_renamelock_exit = layerfs_renamelock_exit,
300 .vfs_fsync = (void *)eopnotsupp,
301 .vfs_opv_descs = umapfs_vnodeopv_descs
302};
303
304static int
305umap_modcmd(modcmd_t cmd, void *arg)
306{
307 int error;
308
309 switch (cmd) {
310 case MODULE_CMD_INIT:
311 error = vfs_attach(&umapfs_vfsops);
312 if (error != 0)
313 break;
314 sysctl_createv(&umapfs_sysctl_log, 0, NULL, NULL,
315 CTLFLAG_PERMANENT,
316 CTLTYPE_NODE, "umap",
317 SYSCTL_DESCR("UID/GID remapping file system"),
318 NULL, 0, NULL, 0,
319 CTL_VFS, 10, CTL_EOL);
320 /*
321 * XXX the "10" above could be dynamic, thereby eliminating
322 * one more instance of the "number to vfs" mapping problem,
323 * but "10" is the order as taken from sys/mount.h
324 */
325 break;
326 case MODULE_CMD_FINI:
327 error = vfs_detach(&umapfs_vfsops);
328 if (error != 0)
329 break;
330 sysctl_teardown(&umapfs_sysctl_log);
331 break;
332 default:
333 error = ENOTTY;
334 break;
335 }
336
337 return (error);
338}
339