devfs_vfsops.c revision 297523
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: stable/10/sys/fs/devfs/devfs_vfsops.c 297523 2016-04-03 14:38:02Z mav $ 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 51static struct unrhdr *devfs_unr; 52 53MALLOC_DEFINE(M_DEVFS, "DEVFS", "DEVFS data"); 54 55static vfs_mount_t devfs_mount; 56static vfs_unmount_t devfs_unmount; 57static vfs_root_t devfs_root; 58static vfs_statfs_t devfs_statfs; 59 60static const char *devfs_opts[] = { 61 "from", "export", "ruleset", NULL 62}; 63 64/* 65 * Mount the filesystem 66 */ 67static int 68devfs_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 166void 167devfs_unmount_final(struct devfs_mount *fmp) 168{ 169 sx_destroy(&fmp->dm_lock); 170 free(fmp, M_DEVFS); 171} 172 173static int 174devfs_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 207static int 208devfs_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 224static int 225devfs_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 239static 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 246VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC | VFCF_JAIL); 247