1 /*-
2 * Copyright (c) 1992, 1993, 1995
3 * The Regents of the University of California. All rights reserved.
4 * Copyright (c) 2000
5 * Poul-Henning Kamp. All rights reserved.
6 *
7 * This code is derived from software donated to Berkeley by
8 * Jan-Simon Pendry.
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. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * @(#)kernfs_vfsops.c 8.10 (Berkeley) 5/14/95
32 * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
33 *
34 * $FreeBSD$
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
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 if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_DEVFS))
85 return (EPERM);
86
87 rsnum = 0;
88 injail = jailed(td->td_ucred);
89
90 if (mp->mnt_optnew != NULL) {
91 if (vfs_filteropt(mp->mnt_optnew, devfs_opts))
92 return (EINVAL);
93
94 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
95 return (EOPNOTSUPP);
96
97 if (vfs_getopt(mp->mnt_optnew, "ruleset", NULL, NULL) == 0 &&
98 (vfs_scanopt(mp->mnt_optnew, "ruleset", "%d",
99 &rsnum) != 1 || rsnum < 0 || rsnum > 65535)) {
100 vfs_mount_error(mp, "%s",
101 "invalid ruleset specification");
102 return (EINVAL);
103 }
104
105 if (injail && rsnum != 0 &&
106 rsnum != td->td_ucred->cr_prison->pr_devfs_rsnum)
107 return (EPERM);
108 }
109
110 /* jails enforce their ruleset */
111 if (injail)
112 rsnum = td->td_ucred->cr_prison->pr_devfs_rsnum;
113
114 if (mp->mnt_flag & MNT_UPDATE) {
115 if (rsnum != 0) {
116 fmp = mp->mnt_data;
117 if (fmp != NULL) {
118 sx_xlock(&fmp->dm_lock);
119 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
120 devfs_ruleset_apply(fmp);
121 sx_xunlock(&fmp->dm_lock);
122 }
123 }
124 return (0);
125 }
126
127 fmp = malloc(sizeof *fmp, M_DEVFS, M_WAITOK | M_ZERO);
128 fmp->dm_idx = alloc_unr(devfs_unr);
129 sx_init(&fmp->dm_lock, "devfsmount");
130 fmp->dm_holdcnt = 1;
131
132 MNT_ILOCK(mp);
133 mp->mnt_flag |= MNT_LOCAL;
134 mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED;
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, 0);
160
161 vfs_mountedfrom(mp, "devfs");
162
163 return (0);
164 }
165
166 void
167 devfs_unmount_final(struct devfs_mount *fmp)
168 {
169 sx_destroy(&fmp->dm_lock);
170 free(fmp, M_DEVFS);
171 }
172
173 static int
174 devfs_unmount(struct mount *mp, int mntflags)
175 {
176 int error;
177 int flags = 0;
178 struct devfs_mount *fmp;
179 int hold;
180 u_int idx;
181
182 fmp = VFSTODEVFS(mp);
183 KASSERT(fmp->dm_mount != NULL,
184 ("devfs_unmount unmounted devfs_mount"));
185 if (mntflags & MNT_FORCE)
186 flags |= FORCECLOSE;
187 /* There is 1 extra root vnode reference from devfs_mount(). */
188 error = vflush(mp, 1, flags, curthread);
189 if (error)
190 return (error);
191 sx_xlock(&fmp->dm_lock);
192 devfs_cleanup(fmp);
193 devfs_rules_cleanup(fmp);
194 fmp->dm_mount = NULL;
195 hold = --fmp->dm_holdcnt;
196 mp->mnt_data = NULL;
197 idx = fmp->dm_idx;
198 sx_xunlock(&fmp->dm_lock);
199 free_unr(devfs_unr, idx);
200 if (hold == 0)
201 devfs_unmount_final(fmp);
202 return 0;
203 }
204
205 /* Return locked reference to root. */
206
207 static int
208 devfs_root(struct mount *mp, int flags, struct vnode **vpp)
209 {
210 int error;
211 struct vnode *vp;
212 struct devfs_mount *dmp;
213
214 dmp = VFSTODEVFS(mp);
215 sx_xlock(&dmp->dm_lock);
216 error = devfs_allocv(dmp->dm_rootdir, mp, LK_EXCLUSIVE, &vp);
217 if (error)
218 return (error);
219 vp->v_vflag |= VV_ROOT;
220 *vpp = vp;
221 return (0);
222 }
223
224 static int
225 devfs_statfs(struct mount *mp, struct statfs *sbp)
226 {
227
228 sbp->f_flags = 0;
229 sbp->f_bsize = DEV_BSIZE;
230 sbp->f_iosize = DEV_BSIZE;
231 sbp->f_blocks = 2; /* 1K to keep df happy */
232 sbp->f_bfree = 0;
233 sbp->f_bavail = 0;
234 sbp->f_files = 0;
235 sbp->f_ffree = 0;
236 return (0);
237 }
238
239 static struct vfsops devfs_vfsops = {
240 .vfs_mount = devfs_mount,
241 .vfs_root = devfs_root,
242 .vfs_statfs = devfs_statfs,
243 .vfs_unmount = devfs_unmount,
244 };
245
246 VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC | VFCF_JAIL);
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