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 if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_DEVFS)) 87 return (EPERM); 88 89 rsnum = 0; 90 injail = jailed(td->td_ucred); 91 92 if (mp->mnt_optnew != NULL) { 93 if (vfs_filteropt(mp->mnt_optnew, devfs_opts)) 94 return (EINVAL); 95 96 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0)) 97 return (EOPNOTSUPP); 98 99 if (vfs_getopt(mp->mnt_optnew, "ruleset", NULL, NULL) == 0 && 100 (vfs_scanopt(mp->mnt_optnew, "ruleset", "%d", 101 &rsnum) != 1 || rsnum < 0 || rsnum > 65535)) { 102 vfs_mount_error(mp, "%s", 103 "invalid ruleset specification"); 104 return (EINVAL); 105 } 106 107 if (injail && rsnum != 0 && 108 rsnum != td->td_ucred->cr_prison->pr_devfs_rsnum) 109 return (EPERM); 110 } 111 112 /* jails enforce their ruleset */ 113 if (injail) 114 rsnum = td->td_ucred->cr_prison->pr_devfs_rsnum; 115 116 if (mp->mnt_flag & MNT_UPDATE) { 117 if (rsnum != 0) { 118 fmp = mp->mnt_data; 119 if (fmp != NULL) { 120 sx_xlock(&fmp->dm_lock); 121 devfs_ruleset_set((devfs_rsnum)rsnum, fmp); 122 devfs_ruleset_apply(fmp); 123 sx_xunlock(&fmp->dm_lock); 124 } 125 } 126 return (0); 127 } 128 129 fmp = malloc(sizeof *fmp, M_DEVFS, M_WAITOK | M_ZERO); 130 fmp->dm_idx = alloc_unr(devfs_unr); 131 sx_init(&fmp->dm_lock, "devfsmount"); 132 fmp->dm_holdcnt = 1; 133 134 MNT_ILOCK(mp); 135 mp->mnt_flag |= MNT_LOCAL; 136 mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED; 137 #ifdef MAC 138 mp->mnt_flag |= MNT_MULTILABEL; 139 #endif 140 MNT_IUNLOCK(mp); 141 fmp->dm_mount = mp; 142 mp->mnt_data = (void *) fmp; 143 vfs_getnewfsid(mp); 144 145 fmp->dm_rootdir = devfs_vmkdir(fmp, NULL, 0, NULL, DEVFS_ROOTINO); 146 147 error = devfs_root(mp, LK_EXCLUSIVE, &rvp); 148 if (error) { 149 sx_destroy(&fmp->dm_lock); 150 free_unr(devfs_unr, fmp->dm_idx); 151 free(fmp, M_DEVFS); 152 return (error); 153 } 154 155 if (rsnum != 0) { 156 sx_xlock(&fmp->dm_lock); 157 devfs_ruleset_set((devfs_rsnum)rsnum, fmp); 158 sx_xunlock(&fmp->dm_lock); 159 } 160 161 VOP_UNLOCK(rvp, 0); 162 163 vfs_mountedfrom(mp, "devfs"); 164 165 return (0); 166 } 167 168 void 169 devfs_unmount_final(struct devfs_mount *fmp) 170 { 171 sx_destroy(&fmp->dm_lock); 172 free(fmp, M_DEVFS); 173 } 174 175 static int 176 devfs_unmount(struct mount *mp, int mntflags) 177 { 178 int error; 179 int flags = 0; 180 struct devfs_mount *fmp; 181 int hold; 182 u_int idx; 183 184 fmp = VFSTODEVFS(mp); 185 KASSERT(fmp->dm_mount != NULL, 186 ("devfs_unmount unmounted devfs_mount")); 187 if (mntflags & MNT_FORCE) 188 flags |= FORCECLOSE; 189 /* There is 1 extra root vnode reference from devfs_mount(). */ 190 error = vflush(mp, 1, flags, curthread); 191 if (error) 192 return (error); 193 sx_xlock(&fmp->dm_lock); 194 devfs_cleanup(fmp); 195 devfs_rules_cleanup(fmp); 196 fmp->dm_mount = NULL; 197 hold = --fmp->dm_holdcnt; 198 mp->mnt_data = NULL; 199 idx = fmp->dm_idx; 200 sx_xunlock(&fmp->dm_lock); 201 free_unr(devfs_unr, idx); 202 if (hold == 0) 203 devfs_unmount_final(fmp); 204 return 0; 205 } 206 207 /* Return locked reference to root. */ 208 209 static int 210 devfs_root(struct mount *mp, int flags, struct vnode **vpp) 211 { 212 int error; 213 struct vnode *vp; 214 struct devfs_mount *dmp; 215 216 dmp = VFSTODEVFS(mp); 217 sx_xlock(&dmp->dm_lock); 218 error = devfs_allocv(dmp->dm_rootdir, mp, LK_EXCLUSIVE, &vp); 219 if (error) 220 return (error); 221 vp->v_vflag |= VV_ROOT; 222 *vpp = vp; 223 return (0); 224 } 225 226 static int 227 devfs_statfs(struct mount *mp, struct statfs *sbp) 228 { 229 230 sbp->f_flags = 0; 231 sbp->f_bsize = DEV_BSIZE; 232 sbp->f_iosize = DEV_BSIZE; 233 sbp->f_blocks = 2; /* 1K to keep df happy */ 234 sbp->f_bfree = 0; 235 sbp->f_bavail = 0; 236 sbp->f_files = 0; 237 sbp->f_ffree = 0; 238 return (0); 239 } 240 241 static struct vfsops devfs_vfsops = { 242 .vfs_mount = devfs_mount, 243 .vfs_root = devfs_root, 244 .vfs_statfs = devfs_statfs, 245 .vfs_unmount = devfs_unmount, 246 }; 247 248 VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC | VFCF_JAIL); 249