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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)dead_vnops.c 8.1 (Berkeley) 6/10/93 30 * $FreeBSD$ 31 */ 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/kernel.h> 36 #include <sys/lock.h> 37 #include <sys/mutex.h> 38 #include <sys/poll.h> 39 #include <sys/vnode.h> 40 41 static int chkvnlock(struct vnode *); 42 /* 43 * Prototypes for dead operations on vnodes. 44 */ 45 static int dead_bmap(struct vop_bmap_args *); 46 static int dead_ioctl(struct vop_ioctl_args *); 47 static int dead_lock(struct vop_lock_args *); 48 static int dead_lookup(struct vop_lookup_args *); 49 static int dead_open(struct vop_open_args *); 50 static int dead_poll(struct vop_poll_args *); 51 static int dead_read(struct vop_read_args *); 52 static int dead_write(struct vop_write_args *); 53 54 vop_t **dead_vnodeop_p; 55 static struct vnodeopv_entry_desc dead_vnodeop_entries[] = { 56 { &vop_default_desc, (vop_t *) vop_defaultop }, 57 { &vop_access_desc, (vop_t *) vop_ebadf }, 58 { &vop_advlock_desc, (vop_t *) vop_ebadf }, 59 { &vop_bmap_desc, (vop_t *) dead_bmap }, 60 { &vop_create_desc, (vop_t *) vop_panic }, 61 { &vop_getattr_desc, (vop_t *) vop_ebadf }, 62 { &vop_inactive_desc, (vop_t *) vop_null }, 63 { &vop_ioctl_desc, (vop_t *) dead_ioctl }, 64 { &vop_link_desc, (vop_t *) vop_panic }, 65 { &vop_lock_desc, (vop_t *) dead_lock }, 66 { &vop_lookup_desc, (vop_t *) dead_lookup }, 67 { &vop_mkdir_desc, (vop_t *) vop_panic }, 68 { &vop_mknod_desc, (vop_t *) vop_panic }, 69 { &vop_open_desc, (vop_t *) dead_open }, 70 { &vop_pathconf_desc, (vop_t *) vop_ebadf }, /* per pathconf(2) */ 71 { &vop_poll_desc, (vop_t *) dead_poll }, 72 { &vop_read_desc, (vop_t *) dead_read }, 73 { &vop_readdir_desc, (vop_t *) vop_ebadf }, 74 { &vop_readlink_desc, (vop_t *) vop_ebadf }, 75 { &vop_reclaim_desc, (vop_t *) vop_null }, 76 { &vop_remove_desc, (vop_t *) vop_panic }, 77 { &vop_rename_desc, (vop_t *) vop_panic }, 78 { &vop_rmdir_desc, (vop_t *) vop_panic }, 79 { &vop_setattr_desc, (vop_t *) vop_ebadf }, 80 { &vop_symlink_desc, (vop_t *) vop_panic }, 81 { &vop_write_desc, (vop_t *) dead_write }, 82 { NULL, NULL } 83 }; 84 static struct vnodeopv_desc dead_vnodeop_opv_desc = 85 { &dead_vnodeop_p, dead_vnodeop_entries }; 86 87 VNODEOP_SET(dead_vnodeop_opv_desc); 88 89 /* 90 * Trivial lookup routine that always fails. 91 */ 92 /* ARGSUSED */ 93 static int 94 dead_lookup(ap) 95 struct vop_lookup_args /* { 96 struct vnode * a_dvp; 97 struct vnode ** a_vpp; 98 struct componentname * a_cnp; 99 } */ *ap; 100 { 101 102 *ap->a_vpp = NULL; 103 return (ENOTDIR); 104 } 105 106 /* 107 * Open always fails as if device did not exist. 108 */ 109 /* ARGSUSED */ 110 static int 111 dead_open(ap) 112 struct vop_open_args /* { 113 struct vnode *a_vp; 114 int a_mode; 115 struct ucred *a_cred; 116 struct proc *a_p; 117 } */ *ap; 118 { 119 120 return (ENXIO); 121 } 122 123 /* 124 * Vnode op for read 125 */ 126 /* ARGSUSED */ 127 static int 128 dead_read(ap) 129 struct vop_read_args /* { 130 struct vnode *a_vp; 131 struct uio *a_uio; 132 int a_ioflag; 133 struct ucred *a_cred; 134 } */ *ap; 135 { 136 137 if (chkvnlock(ap->a_vp)) 138 panic("dead_read: lock"); 139 /* 140 * Return EOF for tty devices, EIO for others 141 */ 142 if ((ap->a_vp->v_vflag & VV_ISTTY) == 0) 143 return (EIO); 144 return (0); 145 } 146 147 /* 148 * Vnode op for write 149 */ 150 /* ARGSUSED */ 151 static int 152 dead_write(ap) 153 struct vop_write_args /* { 154 struct vnode *a_vp; 155 struct uio *a_uio; 156 int a_ioflag; 157 struct ucred *a_cred; 158 } */ *ap; 159 { 160 161 if (chkvnlock(ap->a_vp)) 162 panic("dead_write: lock"); 163 return (EIO); 164 } 165 166 /* 167 * Device ioctl operation. 168 */ 169 /* ARGSUSED */ 170 static int 171 dead_ioctl(ap) 172 struct vop_ioctl_args /* { 173 struct vnode *a_vp; 174 u_long a_command; 175 caddr_t a_data; 176 int a_fflag; 177 struct ucred *a_cred; 178 struct proc *a_p; 179 } */ *ap; 180 { 181 182 if (!chkvnlock(ap->a_vp)) 183 return (ENOTTY); 184 /* XXX: Doesn't this just recurse back here ? */ 185 return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap)); 186 } 187 188 189 /* 190 * Wait until the vnode has finished changing state. 191 */ 192 static int 193 dead_lock(ap) 194 struct vop_lock_args /* { 195 struct vnode *a_vp; 196 int a_flags; 197 struct proc *a_p; 198 } */ *ap; 199 { 200 struct vnode *vp = ap->a_vp; 201 202 /* 203 * Since we are not using the lock manager, we must clear 204 * the interlock here. 205 */ 206 if (ap->a_flags & LK_INTERLOCK) { 207 mtx_unlock(&vp->v_interlock); 208 ap->a_flags &= ~LK_INTERLOCK; 209 } 210 if (!chkvnlock(vp)) 211 return (0); 212 return (VCALL(vp, VOFFSET(vop_lock), ap)); 213 } 214 215 /* 216 * Wait until the vnode has finished changing state. 217 */ 218 static int 219 dead_bmap(ap) 220 struct vop_bmap_args /* { 221 struct vnode *a_vp; 222 daddr_t a_bn; 223 struct vnode **a_vpp; 224 daddr_t *a_bnp; 225 int *a_runp; 226 int *a_runb; 227 } */ *ap; 228 { 229 230 if (!chkvnlock(ap->a_vp)) 231 return (EIO); 232 return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp, ap->a_runb)); 233 } 234 235 /* 236 * We have to wait during times when the vnode is 237 * in a state of change. 238 */ 239 static int 240 chkvnlock(vp) 241 register struct vnode *vp; 242 { 243 int locked = 0; 244 245 VI_LOCK(vp); 246 while (vp->v_iflag & VI_XLOCK) { 247 vp->v_iflag |= VI_XWANT; 248 (void) msleep((caddr_t)vp, VI_MTX(vp), PINOD, "ckvnlk", 0); 249 locked = 1; 250 } 251 VI_UNLOCK(vp); 252 return (locked); 253 } 254 255 /* 256 * Trivial poll routine that always returns POLLHUP. 257 * This is necessary so that a process which is polling a file 258 * gets notified when that file is revoke()d. 259 */ 260 static int 261 dead_poll(ap) 262 struct vop_poll_args *ap; 263 { 264 return (POLLHUP); 265 } 266