1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1992, 1993, 1995
5 * The Regents of the University of California. All rights reserved.
6 * Copyright (c) 2000
7 * Poul-Henning Kamp. All rights reserved.
8 *
9 * This code is derived from software donated to Berkeley by
10 * Jan-Simon Pendry.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)kernfs_vfsops.c 8.10 (Berkeley) 5/14/95
34 * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
35 *
36 * $FreeBSD$
37 */
38
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/kernel.h>
42 #include <sys/lock.h>
43 #include <sys/malloc.h>
44 #include <sys/mount.h>
45 #include <sys/proc.h>
46 #include <sys/sx.h>
47 #include <sys/vnode.h>
48 #include <sys/limits.h>
49 #include <sys/jail.h>
50
51 #include <fs/devfs/devfs.h>
52
53 static struct unrhdr *devfs_unr;
54
55 MALLOC_DEFINE(M_DEVFS, "DEVFS", "DEVFS data");
56
57 static vfs_mount_t devfs_mount;
58 static vfs_unmount_t devfs_unmount;
59 static vfs_root_t devfs_root;
60 static vfs_statfs_t devfs_statfs;
61
62 static const char *devfs_opts[] = {
63 "from", "export", "ruleset", NULL
64 };
65
66 /*
67 * Mount the filesystem
68 */
69 static int
70 devfs_mount(struct mount *mp)
71 {
72 int error;
73 struct devfs_mount *fmp;
74 struct vnode *rvp;
75 struct thread *td = curthread;
76 int injail, rsnum;
77
78 if (devfs_unr == NULL)
79 devfs_unr = new_unrhdr(0, INT_MAX, NULL);
80
81 error = 0;
82
83 if (mp->mnt_flag & MNT_ROOTFS)
84 return (EOPNOTSUPP);
85
86 rsnum = 0;
87 injail = jailed(td->td_ucred);
88
89 if (mp->mnt_optnew != NULL) {
90 if (vfs_filteropt(mp->mnt_optnew, devfs_opts))
91 return (EINVAL);
92
93 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
94 return (EOPNOTSUPP);
95
96 if (vfs_getopt(mp->mnt_optnew, "ruleset", NULL, NULL) == 0 &&
97 (vfs_scanopt(mp->mnt_optnew, "ruleset", "%d",
98 &rsnum) != 1 || rsnum < 0 || rsnum > 65535)) {
99 vfs_mount_error(mp, "%s",
100 "invalid ruleset specification");
101 return (EINVAL);
102 }
103
104 if (injail && rsnum != 0 &&
105 rsnum != td->td_ucred->cr_prison->pr_devfs_rsnum)
106 return (EPERM);
107 }
108
109 /* jails enforce their ruleset */
110 if (injail)
111 rsnum = td->td_ucred->cr_prison->pr_devfs_rsnum;
112
113 if (mp->mnt_flag & MNT_UPDATE) {
114 if (rsnum != 0) {
115 fmp = mp->mnt_data;
116 if (fmp != NULL) {
117 sx_xlock(&fmp->dm_lock);
118 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
119 devfs_ruleset_apply(fmp);
120 sx_xunlock(&fmp->dm_lock);
121 }
122 }
123 return (0);
124 }
125
126 fmp = malloc(sizeof *fmp, M_DEVFS, M_WAITOK | M_ZERO);
127 fmp->dm_idx = alloc_unr(devfs_unr);
128 sx_init(&fmp->dm_lock, "devfsmount");
129 fmp->dm_holdcnt = 1;
130
131 MNT_ILOCK(mp);
132 mp->mnt_flag |= MNT_LOCAL;
133 mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED |
134 MNTK_NOMSYNC;
135 #ifdef MAC
136 mp->mnt_flag |= MNT_MULTILABEL;
137 #endif
138 MNT_IUNLOCK(mp);
139 fmp->dm_mount = mp;
140 mp->mnt_data = (void *) fmp;
141 vfs_getnewfsid(mp);
142
143 fmp->dm_rootdir = devfs_vmkdir(fmp, NULL, 0, NULL, DEVFS_ROOTINO);
144
145 error = devfs_root(mp, LK_EXCLUSIVE, &rvp);
146 if (error) {
147 sx_destroy(&fmp->dm_lock);
148 free_unr(devfs_unr, fmp->dm_idx);
149 free(fmp, M_DEVFS);
150 return (error);
151 }
152
153 if (rsnum != 0) {
154 sx_xlock(&fmp->dm_lock);
155 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
156 sx_xunlock(&fmp->dm_lock);
157 }
158
159 VOP_UNLOCK(rvp);
160 vfs_cache_root_set(mp, rvp);
161
162 vfs_mountedfrom(mp, "devfs");
163
164 return (0);
165 }
166
167 void
168 devfs_unmount_final(struct devfs_mount *fmp)
169 {
170 sx_destroy(&fmp->dm_lock);
171 free(fmp, M_DEVFS);
172 }
173
174 static int
175 devfs_unmount(struct mount *mp, int mntflags)
176 {
177 int error;
178 int flags = 0;
179 struct devfs_mount *fmp;
180 int hold;
181 u_int idx;
182
183 fmp = VFSTODEVFS(mp);
184 KASSERT(fmp->dm_mount != NULL,
185 ("devfs_unmount unmounted devfs_mount"));
186 if (mntflags & MNT_FORCE)
187 flags |= FORCECLOSE;
188 /* There is 1 extra root vnode reference from devfs_mount(). */
189 error = vflush(mp, 1, flags, curthread);
190 if (error)
191 return (error);
192 sx_xlock(&fmp->dm_lock);
193 devfs_cleanup(fmp);
194 devfs_rules_cleanup(fmp);
195 fmp->dm_mount = NULL;
196 hold = --fmp->dm_holdcnt;
197 mp->mnt_data = NULL;
198 idx = fmp->dm_idx;
199 sx_xunlock(&fmp->dm_lock);
200 free_unr(devfs_unr, idx);
201 if (hold == 0)
202 devfs_unmount_final(fmp);
203 return 0;
204 }
205
206 /* Return locked reference to root. */
207
208 static int
209 devfs_root(struct mount *mp, int flags, struct vnode **vpp)
210 {
211 int error;
212 struct vnode *vp;
213 struct devfs_mount *dmp;
214
215 dmp = VFSTODEVFS(mp);
216 sx_xlock(&dmp->dm_lock);
217 error = devfs_allocv(dmp->dm_rootdir, mp, LK_EXCLUSIVE, &vp);
218 if (error)
219 return (error);
220 vp->v_vflag |= VV_ROOT;
221 *vpp = vp;
222 return (0);
223 }
224
225 static int
226 devfs_statfs(struct mount *mp, struct statfs *sbp)
227 {
228
229 sbp->f_flags = 0;
230 sbp->f_bsize = DEV_BSIZE;
231 sbp->f_iosize = DEV_BSIZE;
232 sbp->f_blocks = 2; /* 1K to keep df happy */
233 sbp->f_bfree = 0;
234 sbp->f_bavail = 0;
235 sbp->f_files = 0;
236 sbp->f_ffree = 0;
237 return (0);
238 }
239
240 static struct vfsops devfs_vfsops = {
241 .vfs_mount = devfs_mount,
242 .vfs_root = vfs_cache_root,
243 .vfs_cachedroot = devfs_root,
244 .vfs_statfs = devfs_statfs,
245 .vfs_unmount = devfs_unmount,
246 };
247
248 VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC | VFCF_JAIL);
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