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 * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
33 */
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/lock.h>
39 #include <sys/malloc.h>
40 #include <sys/mount.h>
41 #include <sys/proc.h>
42 #include <sys/sx.h>
43 #include <sys/vnode.h>
44 #include <sys/limits.h>
45 #include <sys/jail.h>
46
47 #include <fs/devfs/devfs.h>
48
49 static struct unrhdr *devfs_unr;
50
51 MALLOC_DEFINE(M_DEVFS, "DEVFS", "DEVFS data");
52
53 static vfs_mount_t devfs_mount;
54 static vfs_unmount_t devfs_unmount;
55 static vfs_root_t devfs_root;
56 static vfs_statfs_t devfs_statfs;
57
58 static const char *devfs_opts[] = {
59 "from", "export", "ruleset", NULL
60 };
61
62 /*
63 * Mount the filesystem
64 */
65 static int
devfs_mount(struct mount * mp)66 devfs_mount(struct mount *mp)
67 {
68 int error;
69 struct devfs_mount *fmp;
70 struct vnode *rvp;
71 struct thread *td = curthread;
72 int injail, rsnum;
73
74 if (devfs_unr == NULL)
75 devfs_unr = new_unrhdr(0, INT_MAX, NULL);
76
77 error = 0;
78
79 if (mp->mnt_flag & MNT_ROOTFS)
80 return (EOPNOTSUPP);
81
82 rsnum = 0;
83 injail = jailed(td->td_ucred);
84
85 if (mp->mnt_optnew != NULL) {
86 if (vfs_filteropt(mp->mnt_optnew, devfs_opts))
87 return (EINVAL);
88
89 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
90 return (EOPNOTSUPP);
91
92 if (vfs_getopt(mp->mnt_optnew, "ruleset", NULL, NULL) == 0 &&
93 (vfs_scanopt(mp->mnt_optnew, "ruleset", "%d",
94 &rsnum) != 1 || rsnum < 0 || rsnum > 65535)) {
95 vfs_mount_error(mp, "%s",
96 "invalid ruleset specification");
97 return (EINVAL);
98 }
99
100 if (injail && rsnum != 0 &&
101 rsnum != td->td_ucred->cr_prison->pr_devfs_rsnum)
102 return (EPERM);
103 }
104
105 /* jails enforce their ruleset */
106 if (injail)
107 rsnum = td->td_ucred->cr_prison->pr_devfs_rsnum;
108
109 if (mp->mnt_flag & MNT_UPDATE) {
110 if (rsnum != 0) {
111 fmp = mp->mnt_data;
112 if (fmp != NULL) {
113 sx_xlock(&fmp->dm_lock);
114 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
115 devfs_ruleset_apply(fmp);
116 sx_xunlock(&fmp->dm_lock);
117 }
118 }
119 return (0);
120 }
121
122 fmp = malloc(sizeof *fmp, M_DEVFS, M_WAITOK | M_ZERO);
123 fmp->dm_idx = alloc_unr(devfs_unr);
124 sx_init(&fmp->dm_lock, "devfsmount");
125 fmp->dm_holdcnt = 1;
126
127 MNT_ILOCK(mp);
128 mp->mnt_flag |= MNT_LOCAL;
129 mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED |
130 MNTK_NOMSYNC;
131 #ifdef MAC
132 mp->mnt_flag |= MNT_MULTILABEL;
133 #endif
134 MNT_IUNLOCK(mp);
135 fmp->dm_mount = mp;
136 mp->mnt_data = (void *) fmp;
137 vfs_getnewfsid(mp);
138
139 fmp->dm_rootdir = devfs_vmkdir(fmp, NULL, 0, NULL, DEVFS_ROOTINO);
140
141 error = devfs_root(mp, LK_EXCLUSIVE, &rvp);
142 if (error) {
143 sx_destroy(&fmp->dm_lock);
144 free_unr(devfs_unr, fmp->dm_idx);
145 free(fmp, M_DEVFS);
146 return (error);
147 }
148
149 if (rsnum != 0) {
150 sx_xlock(&fmp->dm_lock);
151 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
152 sx_xunlock(&fmp->dm_lock);
153 }
154
155 VOP_UNLOCK(rvp);
156 vfs_cache_root_set(mp, rvp);
157
158 vfs_mountedfrom(mp, "devfs");
159
160 return (0);
161 }
162
163 void
devfs_unmount_final(struct devfs_mount * fmp)164 devfs_unmount_final(struct devfs_mount *fmp)
165 {
166 sx_destroy(&fmp->dm_lock);
167 free(fmp, M_DEVFS);
168 }
169
170 static int
devfs_unmount(struct mount * mp,int mntflags)171 devfs_unmount(struct mount *mp, int mntflags)
172 {
173 int error;
174 int flags = 0;
175 struct devfs_mount *fmp;
176 int hold;
177 u_int idx;
178
179 fmp = VFSTODEVFS(mp);
180 KASSERT(fmp->dm_mount != NULL,
181 ("devfs_unmount unmounted devfs_mount"));
182 if (mntflags & MNT_FORCE)
183 flags |= FORCECLOSE;
184 /* There is 1 extra root vnode reference from devfs_mount(). */
185 error = vflush(mp, 1, flags, curthread);
186 if (error)
187 return (error);
188 sx_xlock(&fmp->dm_lock);
189 devfs_cleanup(fmp);
190 devfs_rules_cleanup(fmp);
191 fmp->dm_mount = NULL;
192 hold = --fmp->dm_holdcnt;
193 mp->mnt_data = NULL;
194 idx = fmp->dm_idx;
195 sx_xunlock(&fmp->dm_lock);
196 free_unr(devfs_unr, idx);
197 if (hold == 0)
198 devfs_unmount_final(fmp);
199 return 0;
200 }
201
202 /* Return locked reference to root. */
203
204 static int
devfs_root(struct mount * mp,int flags,struct vnode ** vpp)205 devfs_root(struct mount *mp, int flags, struct vnode **vpp)
206 {
207 int error;
208 struct vnode *vp;
209 struct devfs_mount *dmp;
210
211 dmp = VFSTODEVFS(mp);
212 sx_xlock(&dmp->dm_lock);
213 error = devfs_allocv(dmp->dm_rootdir, mp, LK_EXCLUSIVE, &vp);
214 if (error)
215 return (error);
216 vp->v_vflag |= VV_ROOT;
217 *vpp = vp;
218 return (0);
219 }
220
221 static int
devfs_statfs(struct mount * mp,struct statfs * sbp)222 devfs_statfs(struct mount *mp, struct statfs *sbp)
223 {
224
225 sbp->f_flags = mp->mnt_flag & MNT_IGNORE;
226 sbp->f_bsize = DEV_BSIZE;
227 sbp->f_iosize = DEV_BSIZE;
228 sbp->f_blocks = 2; /* 1K to keep df happy */
229 sbp->f_bfree = 2;
230 sbp->f_bavail = 2;
231 sbp->f_files = 0;
232 sbp->f_ffree = 0;
233 return (0);
234 }
235
236 static struct vfsops devfs_vfsops = {
237 .vfs_mount = devfs_mount,
238 .vfs_root = vfs_cache_root,
239 .vfs_cachedroot = devfs_root,
240 .vfs_statfs = devfs_statfs,
241 .vfs_unmount = devfs_unmount,
242 };
243
244 VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC | VFCF_JAIL);
245