1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/malloc.h>
42 #include <sys/mount.h>
43 #include <sys/proc.h>
44 #include <sys/sx.h>
45 #include <sys/vnode.h>
46 #include <sys/limits.h>
47 #include <sys/jail.h>
48
49 #include <fs/devfs/devfs.h>
50
51 static struct unrhdr *devfs_unr;
52
53 MALLOC_DEFINE(M_DEVFS, "DEVFS", "DEVFS data");
54
55 static vfs_mount_t devfs_mount;
56 static vfs_unmount_t devfs_unmount;
57 static vfs_root_t devfs_root;
58 static vfs_statfs_t devfs_statfs;
59
60 static const char *devfs_opts[] = {
61 "from", "export", "ruleset", NULL
62 };
63
64 /*
65 * Mount the filesystem
66 */
67 static int
devfs_mount(struct mount * mp)68 devfs_mount(struct mount *mp)
69 {
70 int error;
71 struct devfs_mount *fmp;
72 struct vnode *rvp;
73 struct thread *td = curthread;
74 int injail, rsnum;
75
76 if (devfs_unr == NULL)
77 devfs_unr = new_unrhdr(0, INT_MAX, NULL);
78
79 error = 0;
80
81 if (mp->mnt_flag & MNT_ROOTFS)
82 return (EOPNOTSUPP);
83
84 rsnum = 0;
85 injail = jailed(td->td_ucred);
86
87 if (mp->mnt_optnew != NULL) {
88 if (vfs_filteropt(mp->mnt_optnew, devfs_opts))
89 return (EINVAL);
90
91 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
92 return (EOPNOTSUPP);
93
94 if (vfs_getopt(mp->mnt_optnew, "ruleset", NULL, NULL) == 0 &&
95 (vfs_scanopt(mp->mnt_optnew, "ruleset", "%d",
96 &rsnum) != 1 || rsnum < 0 || rsnum > 65535)) {
97 vfs_mount_error(mp, "%s",
98 "invalid ruleset specification");
99 return (EINVAL);
100 }
101
102 if (injail && rsnum != 0 &&
103 rsnum != td->td_ucred->cr_prison->pr_devfs_rsnum)
104 return (EPERM);
105 }
106
107 /* jails enforce their ruleset */
108 if (injail)
109 rsnum = td->td_ucred->cr_prison->pr_devfs_rsnum;
110
111 if (mp->mnt_flag & MNT_UPDATE) {
112 if (rsnum != 0) {
113 fmp = mp->mnt_data;
114 if (fmp != NULL) {
115 sx_xlock(&fmp->dm_lock);
116 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
117 devfs_ruleset_apply(fmp);
118 sx_xunlock(&fmp->dm_lock);
119 }
120 }
121 return (0);
122 }
123
124 fmp = malloc(sizeof *fmp, M_DEVFS, M_WAITOK | M_ZERO);
125 fmp->dm_idx = alloc_unr(devfs_unr);
126 sx_init(&fmp->dm_lock, "devfsmount");
127 fmp->dm_holdcnt = 1;
128
129 MNT_ILOCK(mp);
130 mp->mnt_flag |= MNT_LOCAL;
131 mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED |
132 MNTK_NOMSYNC;
133 #ifdef MAC
134 mp->mnt_flag |= MNT_MULTILABEL;
135 #endif
136 MNT_IUNLOCK(mp);
137 fmp->dm_mount = mp;
138 mp->mnt_data = (void *) fmp;
139 vfs_getnewfsid(mp);
140
141 fmp->dm_rootdir = devfs_vmkdir(fmp, NULL, 0, NULL, DEVFS_ROOTINO);
142
143 error = devfs_root(mp, LK_EXCLUSIVE, &rvp);
144 if (error) {
145 sx_destroy(&fmp->dm_lock);
146 free_unr(devfs_unr, fmp->dm_idx);
147 free(fmp, M_DEVFS);
148 return (error);
149 }
150
151 if (rsnum != 0) {
152 sx_xlock(&fmp->dm_lock);
153 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
154 sx_xunlock(&fmp->dm_lock);
155 }
156
157 VOP_UNLOCK(rvp);
158 vfs_cache_root_set(mp, rvp);
159
160 vfs_mountedfrom(mp, "devfs");
161
162 return (0);
163 }
164
165 void
devfs_unmount_final(struct devfs_mount * fmp)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
devfs_unmount(struct mount * mp,int mntflags)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
devfs_root(struct mount * mp,int flags,struct vnode ** vpp)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
devfs_statfs(struct mount * mp,struct statfs * sbp)224 devfs_statfs(struct mount *mp, struct statfs *sbp)
225 {
226
227 sbp->f_flags = mp->mnt_flag & MNT_IGNORE;
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 = 2;
232 sbp->f_bavail = 2;
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 = vfs_cache_root,
241 .vfs_cachedroot = devfs_root,
242 .vfs_statfs = devfs_statfs,
243 .vfs_unmount = devfs_unmount,
244 };
245
246 VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC | VFCF_JAIL);
247