1 /* $NetBSD: umap_vfsops.c,v 1.104 2022/11/04 11:20:40 hannken 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 1.104 2022/11/04 11:20:40 hannken 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/syslog.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
61 MODULE(MODULE_CLASS_VFS, umap, "layerfs");
62
63 VFS_PROTOS(umapfs);
64
65 /*
66 * Mount umap layer
67 */
68 int
umapfs_mount(struct mount * mp,const char * path,void * data,size_t * data_len)69 umapfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
70 {
71 struct lwp *l = curlwp;
72 struct pathbuf *pb;
73 struct nameidata nd;
74 struct umap_args *args = data;
75 struct vnode *lowerrootvp, *vp;
76 struct umap_mount *amp;
77 int error;
78 #ifdef UMAPFS_DIAGNOSTIC
79 int i;
80 #endif
81 fsid_t tfsid;
82
83 if (args == NULL)
84 return EINVAL;
85 if (*data_len < sizeof *args) {
86 #ifdef UMAPFS_DIAGNOSTIC
87 printf("mount_umap: data len %d < args %d\n",
88 (int)*data_len, (int)(sizeof *args));
89 #endif
90 return EINVAL;
91 }
92
93 if (mp->mnt_flag & MNT_GETARGS) {
94 amp = MOUNTTOUMAPMOUNT(mp);
95 if (amp == NULL)
96 return EIO;
97 args->la.target = NULL;
98 args->nentries = amp->info_nentries;
99 args->gnentries = amp->info_gnentries;
100 *data_len = sizeof *args;
101 return 0;
102 }
103
104 /* only for root */
105 error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_MOUNT,
106 KAUTH_REQ_SYSTEM_MOUNT_UMAP, NULL, NULL, NULL);
107 if (error)
108 return error;
109
110 #ifdef UMAPFS_DIAGNOSTIC
111 printf("umapfs_mount(mp = %p)\n", mp);
112 #endif
113
114 /*
115 * Update is not supported
116 */
117 if (mp->mnt_flag & MNT_UPDATE)
118 return EOPNOTSUPP;
119
120 /*
121 * Find lower node
122 */
123 error = pathbuf_copyin(args->umap_target, &pb);
124 if (error) {
125 return error;
126 }
127 NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, pb);
128 if ((error = namei(&nd)) != 0) {
129 pathbuf_destroy(pb);
130 return error;
131 }
132
133 /*
134 * Sanity check on lower vnode
135 */
136 lowerrootvp = nd.ni_vp;
137 pathbuf_destroy(pb);
138 #ifdef UMAPFS_DIAGNOSTIC
139 printf("vp = %p, check for VDIR...\n", lowerrootvp);
140 #endif
141
142 if (lowerrootvp->v_type != VDIR) {
143 vput(lowerrootvp);
144 return (EINVAL);
145 }
146
147 #ifdef UMAPFS_DIAGNOSTIC
148 printf("mp = %p\n", mp);
149 #endif
150
151 amp = kmem_zalloc(sizeof(struct umap_mount), KM_SLEEP);
152 mp->mnt_data = amp;
153
154 /*
155 * Now copy in the number of entries and maps for umap mapping.
156 */
157 if (args->nentries < 0 || args->nentries > MAPFILEENTRIES ||
158 args->gnentries < 0 || args->gnentries > GMAPFILEENTRIES) {
159 vput(lowerrootvp);
160 return (EINVAL);
161 }
162
163 amp->info_nentries = args->nentries;
164 amp->info_gnentries = args->gnentries;
165 error = copyin(args->mapdata, amp->info_mapdata,
166 2*sizeof(u_long)*args->nentries);
167 if (error) {
168 vput(lowerrootvp);
169 return (error);
170 }
171
172 #ifdef UMAPFS_DIAGNOSTIC
173 printf("umap_mount:nentries %d\n",args->nentries);
174 for (i = 0; i < args->nentries; i++)
175 printf(" %ld maps to %ld\n", amp->info_mapdata[i][0],
176 amp->info_mapdata[i][1]);
177 #endif
178
179 error = copyin(args->gmapdata, amp->info_gmapdata,
180 2*sizeof(u_long)*args->gnentries);
181 if (error) {
182 vput(lowerrootvp);
183 return (error);
184 }
185
186 #ifdef UMAPFS_DIAGNOSTIC
187 printf("umap_mount:gnentries %d\n",args->gnentries);
188 for (i = 0; i < args->gnentries; i++)
189 printf("\tgroup %ld maps to %ld\n",
190 amp->info_gmapdata[i][0],
191 amp->info_gmapdata[i][1]);
192 #endif
193
194 /*
195 * Make sure the mount point's sufficiently initialized
196 * that the node create call will work.
197 */
198 tfsid.__fsid_val[0] = (int32_t)args->fsid;
199 tfsid.__fsid_val[1] = makefstype(MOUNT_UMAP);
200 if (tfsid.__fsid_val[0] == 0) {
201 log(LOG_WARNING, "umapfs: fsid given as 0, ignoring\n");
202 vfs_getnewfsid(mp);
203 } else if (vfs_getvfs(&tfsid)) {
204 log(LOG_WARNING, "umapfs: fsid %x already mounted\n",
205 tfsid.__fsid_val[0]);
206 vfs_getnewfsid(mp);
207 } else {
208 mp->mnt_stat.f_fsidx.__fsid_val[0] = tfsid.__fsid_val[0];
209 mp->mnt_stat.f_fsidx.__fsid_val[1] = tfsid.__fsid_val[1];
210 mp->mnt_stat.f_fsid = tfsid.__fsid_val[0];
211 }
212 log(LOG_DEBUG, "umapfs: using fsid %x/%x\n",
213 mp->mnt_stat.f_fsidx.__fsid_val[0],
214 mp->mnt_stat.f_fsidx.__fsid_val[1]);
215 error = vfs_set_lowermount(mp, lowerrootvp->v_mount);
216 if (error) {
217 vput(lowerrootvp);
218 kmem_free(amp, sizeof(struct umap_mount));
219 return error;
220 }
221
222 amp->umapm_size = sizeof(struct umap_node);
223 amp->umapm_tag = VT_UMAP;
224 amp->umapm_bypass = umap_bypass;
225 amp->umapm_vnodeop_p = umap_vnodeop_p;
226
227 /*
228 * fix up umap node for root vnode.
229 */
230 VOP_UNLOCK(lowerrootvp);
231 error = layer_node_create(mp, lowerrootvp, &vp);
232 /*
233 * Make sure the node alias worked
234 */
235 if (error) {
236 vrele(lowerrootvp);
237 kmem_free(amp, sizeof(struct umap_mount));
238 return error;
239 }
240
241 /*
242 * Keep a held reference to the root vnode.
243 * It is vrele'd in umapfs_unmount.
244 */
245 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
246 vp->v_vflag |= VV_ROOT;
247 amp->umapm_rootvp = vp;
248 VOP_UNLOCK(vp);
249
250 error = set_statvfs_info(path, UIO_USERSPACE, args->umap_target,
251 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
252 if (error)
253 return error;
254
255 if (mp->mnt_lower->mnt_flag & MNT_LOCAL)
256 mp->mnt_flag |= MNT_LOCAL;
257 #ifdef UMAPFS_DIAGNOSTIC
258 printf("umapfs_mount: lower %s, alias at %s\n",
259 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
260 #endif
261 return 0;
262 }
263
264 /*
265 * Free reference to umap layer
266 */
267 int
umapfs_unmount(struct mount * mp,int mntflags)268 umapfs_unmount(struct mount *mp, int mntflags)
269 {
270 struct umap_mount *amp = MOUNTTOUMAPMOUNT(mp);
271 struct vnode *rtvp = amp->umapm_rootvp;
272 int error;
273 int flags = 0;
274
275 #ifdef UMAPFS_DIAGNOSTIC
276 printf("umapfs_unmount(mp = %p)\n", mp);
277 #endif
278
279 if (mntflags & MNT_FORCE)
280 flags |= FORCECLOSE;
281
282 if (vrefcnt(rtvp) > 1 && (mntflags & MNT_FORCE) == 0)
283 return (EBUSY);
284 if ((error = vflush(mp, rtvp, flags)) != 0)
285 return (error);
286
287 #ifdef UMAPFS_DIAGNOSTIC
288 vprint("alias root of lower", rtvp);
289 #endif
290 /*
291 * Blow it away for future re-use
292 */
293 vgone(rtvp);
294 /*
295 * Finally, throw away the umap_mount structure
296 */
297 kmem_free(amp, sizeof(struct umap_mount));
298 mp->mnt_data = NULL;
299 return 0;
300 }
301
302 extern const struct vnodeopv_desc umapfs_vnodeop_opv_desc;
303
304 const struct vnodeopv_desc * const umapfs_vnodeopv_descs[] = {
305 &umapfs_vnodeop_opv_desc,
306 NULL,
307 };
308
309 struct vfsops umapfs_vfsops = {
310 .vfs_name = MOUNT_UMAP,
311 .vfs_min_mount_data = sizeof (struct umap_args),
312 .vfs_mount = umapfs_mount,
313 .vfs_start = layerfs_start,
314 .vfs_unmount = umapfs_unmount,
315 .vfs_root = layerfs_root,
316 .vfs_quotactl = layerfs_quotactl,
317 .vfs_statvfs = layerfs_statvfs,
318 .vfs_sync = layerfs_sync,
319 .vfs_loadvnode = layerfs_loadvnode,
320 .vfs_vget = layerfs_vget,
321 .vfs_fhtovp = layerfs_fhtovp,
322 .vfs_vptofh = layerfs_vptofh,
323 .vfs_init = layerfs_init,
324 .vfs_done = layerfs_done,
325 .vfs_snapshot = layerfs_snapshot,
326 .vfs_extattrctl = vfs_stdextattrctl,
327 .vfs_suspendctl = layerfs_suspendctl,
328 .vfs_renamelock_enter = layerfs_renamelock_enter,
329 .vfs_renamelock_exit = layerfs_renamelock_exit,
330 .vfs_fsync = (void *)eopnotsupp,
331 .vfs_opv_descs = umapfs_vnodeopv_descs
332 };
333
334 SYSCTL_SETUP(umapfs_sysctl_setup, "umapfs sysctl")
335 {
336
337 sysctl_createv(clog, 0, NULL, NULL,
338 CTLFLAG_PERMANENT,
339 CTLTYPE_NODE, "umap",
340 SYSCTL_DESCR("UID/GID remapping file system"),
341 NULL, 0, NULL, 0,
342 CTL_VFS, 10, CTL_EOL);
343 /*
344 * XXX the "10" above could be dynamic, thereby eliminating
345 * one more instance of the "number to vfs" mapping problem,
346 * but "10" is the order as taken from sys/mount.h
347 */
348 }
349
350 static int
umap_modcmd(modcmd_t cmd,void * arg)351 umap_modcmd(modcmd_t cmd, void *arg)
352 {
353 int error;
354
355 switch (cmd) {
356 case MODULE_CMD_INIT:
357 error = vfs_attach(&umapfs_vfsops);
358 if (error != 0)
359 break;
360 break;
361 case MODULE_CMD_FINI:
362 error = vfs_detach(&umapfs_vfsops);
363 if (error != 0)
364 break;
365 break;
366 default:
367 error = ENOTTY;
368 break;
369 }
370
371 return (error);
372 }
373