1 /* 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. 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 * @(#)dead_vnops.c 8.1 (Berkeley) 6/10/93 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/mutex.h> 42 #include <sys/poll.h> 43 #include <sys/vnode.h> 44 45 static int chkvnlock(struct vnode *); 46 /* 47 * Prototypes for dead operations on vnodes. 48 */ 49 static int dead_bmap(struct vop_bmap_args *); 50 static int dead_ioctl(struct vop_ioctl_args *); 51 static int dead_lock(struct vop_lock_args *); 52 static int dead_lookup(struct vop_lookup_args *); 53 static int dead_open(struct vop_open_args *); 54 static int dead_poll(struct vop_poll_args *); 55 static int dead_read(struct vop_read_args *); 56 static int dead_write(struct vop_write_args *); 57 58 vop_t **dead_vnodeop_p; 59 static struct vnodeopv_entry_desc dead_vnodeop_entries[] = { 60 { &vop_default_desc, (vop_t *) vop_defaultop }, 61 { &vop_access_desc, (vop_t *) vop_ebadf }, 62 { &vop_advlock_desc, (vop_t *) vop_ebadf }, 63 { &vop_bmap_desc, (vop_t *) dead_bmap }, 64 { &vop_create_desc, (vop_t *) vop_panic }, 65 { &vop_getattr_desc, (vop_t *) vop_ebadf }, 66 { &vop_inactive_desc, (vop_t *) vop_null }, 67 { &vop_ioctl_desc, (vop_t *) dead_ioctl }, 68 { &vop_link_desc, (vop_t *) vop_panic }, 69 { &vop_lock_desc, (vop_t *) dead_lock }, 70 { &vop_lookup_desc, (vop_t *) dead_lookup }, 71 { &vop_mkdir_desc, (vop_t *) vop_panic }, 72 { &vop_mknod_desc, (vop_t *) vop_panic }, 73 { &vop_open_desc, (vop_t *) dead_open }, 74 { &vop_pathconf_desc, (vop_t *) vop_ebadf }, /* per pathconf(2) */ 75 { &vop_poll_desc, (vop_t *) dead_poll }, 76 { &vop_read_desc, (vop_t *) dead_read }, 77 { &vop_readdir_desc, (vop_t *) vop_ebadf }, 78 { &vop_readlink_desc, (vop_t *) vop_ebadf }, 79 { &vop_reclaim_desc, (vop_t *) vop_null }, 80 { &vop_remove_desc, (vop_t *) vop_panic }, 81 { &vop_rename_desc, (vop_t *) vop_panic }, 82 { &vop_rmdir_desc, (vop_t *) vop_panic }, 83 { &vop_setattr_desc, (vop_t *) vop_ebadf }, 84 { &vop_symlink_desc, (vop_t *) vop_panic }, 85 { &vop_write_desc, (vop_t *) dead_write }, 86 { NULL, NULL } 87 }; 88 static struct vnodeopv_desc dead_vnodeop_opv_desc = 89 { &dead_vnodeop_p, dead_vnodeop_entries }; 90 91 VNODEOP_SET(dead_vnodeop_opv_desc); 92 93 /* 94 * Trivial lookup routine that always fails. 95 */ 96 /* ARGSUSED */ 97 static int 98 dead_lookup(ap) 99 struct vop_lookup_args /* { 100 struct vnode * a_dvp; 101 struct vnode ** a_vpp; 102 struct componentname * a_cnp; 103 } */ *ap; 104 { 105 106 *ap->a_vpp = NULL; 107 return (ENOTDIR); 108 } 109 110 /* 111 * Open always fails as if device did not exist. 112 */ 113 /* ARGSUSED */ 114 static int 115 dead_open(ap) 116 struct vop_open_args /* { 117 struct vnode *a_vp; 118 int a_mode; 119 struct ucred *a_cred; 120 struct proc *a_p; 121 } */ *ap; 122 { 123 124 return (ENXIO); 125 } 126 127 /* 128 * Vnode op for read 129 */ 130 /* ARGSUSED */ 131 static int 132 dead_read(ap) 133 struct vop_read_args /* { 134 struct vnode *a_vp; 135 struct uio *a_uio; 136 int a_ioflag; 137 struct ucred *a_cred; 138 } */ *ap; 139 { 140 141 if (chkvnlock(ap->a_vp)) 142 panic("dead_read: lock"); 143 /* 144 * Return EOF for tty devices, EIO for others 145 */ 146 if ((ap->a_vp->v_vflag & VV_ISTTY) == 0) 147 return (EIO); 148 return (0); 149 } 150 151 /* 152 * Vnode op for write 153 */ 154 /* ARGSUSED */ 155 static int 156 dead_write(ap) 157 struct vop_write_args /* { 158 struct vnode *a_vp; 159 struct uio *a_uio; 160 int a_ioflag; 161 struct ucred *a_cred; 162 } */ *ap; 163 { 164 165 if (chkvnlock(ap->a_vp)) 166 panic("dead_write: lock"); 167 return (EIO); 168 } 169 170 /* 171 * Device ioctl operation. 172 */ 173 /* ARGSUSED */ 174 static int 175 dead_ioctl(ap) 176 struct vop_ioctl_args /* { 177 struct vnode *a_vp; 178 u_long a_command; 179 caddr_t a_data; 180 int a_fflag; 181 struct ucred *a_cred; 182 struct proc *a_p; 183 } */ *ap; 184 { 185 186 if (!chkvnlock(ap->a_vp)) 187 return (ENOTTY); 188 /* XXX: Doesn't this just recurse back here ? */ 189 return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap)); 190 } 191 192 193 /* 194 * Wait until the vnode has finished changing state. 195 */ 196 static int 197 dead_lock(ap) 198 struct vop_lock_args /* { 199 struct vnode *a_vp; 200 int a_flags; 201 struct proc *a_p; 202 } */ *ap; 203 { 204 struct vnode *vp = ap->a_vp; 205 206 /* 207 * Since we are not using the lock manager, we must clear 208 * the interlock here. 209 */ 210 if (ap->a_flags & LK_INTERLOCK) { 211 mtx_unlock(&vp->v_interlock); 212 ap->a_flags &= ~LK_INTERLOCK; 213 } 214 if (!chkvnlock(vp)) 215 return (0); 216 return (VCALL(vp, VOFFSET(vop_lock), ap)); 217 } 218 219 /* 220 * Wait until the vnode has finished changing state. 221 */ 222 static int 223 dead_bmap(ap) 224 struct vop_bmap_args /* { 225 struct vnode *a_vp; 226 daddr_t a_bn; 227 struct vnode **a_vpp; 228 daddr_t *a_bnp; 229 int *a_runp; 230 int *a_runb; 231 } */ *ap; 232 { 233 234 if (!chkvnlock(ap->a_vp)) 235 return (EIO); 236 return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp, ap->a_runb)); 237 } 238 239 /* 240 * We have to wait during times when the vnode is 241 * in a state of change. 242 */ 243 static int 244 chkvnlock(vp) 245 register struct vnode *vp; 246 { 247 int locked = 0; 248 249 VI_LOCK(vp); 250 while (vp->v_iflag & VI_XLOCK) { 251 vp->v_iflag |= VI_XWANT; 252 (void) msleep((caddr_t)vp, VI_MTX(vp), PINOD, "ckvnlk", 0); 253 locked = 1; 254 } 255 VI_UNLOCK(vp); 256 return (locked); 257 } 258 259 /* 260 * Trivial poll routine that always returns POLLHUP. 261 * This is necessary so that a process which is polling a file 262 * gets notified when that file is revoke()d. 263 */ 264 static int 265 dead_poll(ap) 266 struct vop_poll_args *ap; 267 { 268 return (POLLHUP); 269 } 270