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: releng/12.0/sys/fs/devfs/devfs_vfsops.c 333263 2018-05-04 20:54:27Z jamie $
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 #ifdef MAC
135 mp->mnt_flag |= MNT_MULTILABEL;
136 #endif
137 MNT_IUNLOCK(mp);
138 fmp->dm_mount = mp;
139 mp->mnt_data = (void *) fmp;
140 vfs_getnewfsid(mp);
141
142 fmp->dm_rootdir = devfs_vmkdir(fmp, NULL, 0, NULL, DEVFS_ROOTINO);
143
144 error = devfs_root(mp, LK_EXCLUSIVE, &rvp);
145 if (error) {
146 sx_destroy(&fmp->dm_lock);
147 free_unr(devfs_unr, fmp->dm_idx);
148 free(fmp, M_DEVFS);
149 return (error);
150 }
151
152 if (rsnum != 0) {
153 sx_xlock(&fmp->dm_lock);
154 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
155 sx_xunlock(&fmp->dm_lock);
156 }
157
158 VOP_UNLOCK(rvp, 0);
159
160 vfs_mountedfrom(mp, "devfs");
161
162 return (0);
163 }
164
165 void
166 devfs_unmount_final(struct devfs_mount *fmp)
167 {
168 sx_destroy(&fmp->dm_lock);
169 free(fmp, M_DEVFS);
170 }
171
172 static int
173 devfs_unmount(struct mount *mp, int mntflags)
174 {
175 int error;
176 int flags = 0;
177 struct devfs_mount *fmp;
178 int hold;
179 u_int idx;
180
181 fmp = VFSTODEVFS(mp);
182 KASSERT(fmp->dm_mount != NULL,
183 ("devfs_unmount unmounted devfs_mount"));
184 if (mntflags & MNT_FORCE)
185 flags |= FORCECLOSE;
186 /* There is 1 extra root vnode reference from devfs_mount(). */
187 error = vflush(mp, 1, flags, curthread);
188 if (error)
189 return (error);
190 sx_xlock(&fmp->dm_lock);
191 devfs_cleanup(fmp);
192 devfs_rules_cleanup(fmp);
193 fmp->dm_mount = NULL;
194 hold = --fmp->dm_holdcnt;
195 mp->mnt_data = NULL;
196 idx = fmp->dm_idx;
197 sx_xunlock(&fmp->dm_lock);
198 free_unr(devfs_unr, idx);
199 if (hold == 0)
200 devfs_unmount_final(fmp);
201 return 0;
202 }
203
204 /* Return locked reference to root. */
205
206 static int
207 devfs_root(struct mount *mp, int flags, struct vnode **vpp)
208 {
209 int error;
210 struct vnode *vp;
211 struct devfs_mount *dmp;
212
213 dmp = VFSTODEVFS(mp);
214 sx_xlock(&dmp->dm_lock);
215 error = devfs_allocv(dmp->dm_rootdir, mp, LK_EXCLUSIVE, &vp);
216 if (error)
217 return (error);
218 vp->v_vflag |= VV_ROOT;
219 *vpp = vp;
220 return (0);
221 }
222
223 static int
224 devfs_statfs(struct mount *mp, struct statfs *sbp)
225 {
226
227 sbp->f_flags = 0;
228 sbp->f_bsize = DEV_BSIZE;
229 sbp->f_iosize = DEV_BSIZE;
230 sbp->f_blocks = 2; /* 1K to keep df happy */
231 sbp->f_bfree = 0;
232 sbp->f_bavail = 0;
233 sbp->f_files = 0;
234 sbp->f_ffree = 0;
235 return (0);
236 }
237
238 static struct vfsops devfs_vfsops = {
239 .vfs_mount = devfs_mount,
240 .vfs_root = devfs_root,
241 .vfs_statfs = devfs_statfs,
242 .vfs_unmount = devfs_unmount,
243 };
244
245 VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC | VFCF_JAIL);
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