sys/vfs/deadfs/dead_vnops.c

   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: src/sys/miscfs/deadfs/dead_vnops.c,v 1.26 1999/08/28 00:46:42 peter Exp $
  35  * $DragonFly: src/sys/vfs/deadfs/dead_vnops.c,v 1.20 2007/08/13 17:31:56 dillon Exp $
  36  */
  37
  38 #include <sys/param.h>
  39 #include <sys/systm.h>
  40 #include <sys/kernel.h>
  41 #include <sys/lock.h>
  42 #include <sys/vnode.h>
  43 #include <sys/fcntl.h>
  44 #include <sys/buf.h>
  45 #include <sys/poll.h>
  46
  47 /*
  48  * Prototypes for dead operations on vnodes.
  49  */
  50 static int      dead_badop (void);
  51 static int      dead_bmap (struct vop_bmap_args *);
  52 static int      dead_ioctl (struct vop_ioctl_args *);
  53 static int      dead_lookup (struct vop_old_lookup_args *);
  54 static int      dead_open (struct vop_open_args *);
  55 static int      dead_close (struct vop_close_args *);
  56 static int      dead_poll (struct vop_poll_args *);
  57 static int      dead_print (struct vop_print_args *);
  58 static int      dead_read (struct vop_read_args *);
  59 static int      dead_write (struct vop_write_args *);
  60
  61 struct vop_ops dead_vnode_vops = {
  62         .vop_default =          vop_defaultop,
  63         .vop_access =           (void *)vop_ebadf,
  64         .vop_advlock =          (void *)vop_ebadf,
  65         .vop_bmap =             dead_bmap,
  66         .vop_old_create =       (void *)dead_badop,
  67         .vop_getattr =          (void *)vop_ebadf,
  68         .vop_inactive =         (void *)vop_null,
  69         .vop_ioctl =            dead_ioctl,
  70         .vop_old_link =         (void *)dead_badop,
  71         .vop_old_lookup =       dead_lookup,
  72         .vop_old_mkdir =        (void *)dead_badop,
  73         .vop_old_mknod =        (void *)dead_badop,
  74         .vop_mmap =             (void *)dead_badop,
  75         .vop_open =             dead_open,
  76         .vop_close =            dead_close,
  77         .vop_pathconf =         (void *)vop_ebadf,      /* per pathconf(2) */
  78         .vop_poll =             dead_poll,
  79         .vop_print =            dead_print,
  80         .vop_read =             dead_read,
  81         .vop_readdir =          (void *)vop_ebadf,
  82         .vop_readlink =         (void *)vop_ebadf,
  83         .vop_reclaim =          (void *)vop_null,
  84         .vop_old_remove =       (void *)dead_badop,
  85         .vop_old_rename =       (void *)dead_badop,
  86         .vop_old_rmdir =        (void *)dead_badop,
  87         .vop_setattr =          (void *)vop_ebadf,
  88         .vop_old_symlink =      (void *)dead_badop,
  89         .vop_write =            dead_write
  90 };
  91
  92 struct vop_ops *dead_vnode_vops_p = &dead_vnode_vops;
  93
  94 VNODEOP_SET(dead_vnode_vops);
  95
  96 /*
  97  * Trivial lookup routine that always fails.
  98  *
  99  * dead_lookup(struct vnode *a_dvp, struct vnode **a_vpp,
 100  *             struct componentname *a_cnp)
 101  */
 102 /* ARGSUSED */
 103 static int
 104 dead_lookup(struct vop_old_lookup_args *ap)
 105 {
 106         *ap->a_vpp = NULL;
 107         return (ENOTDIR);
 108 }
 109
 110 /*
 111  * Open always fails as if device did not exist.
 112  *
 113  * dead_open(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
 114  *           struct proc *a_p)
 115  */
 116 /* ARGSUSED */
 117 static int
 118 dead_open(struct vop_open_args *ap)
 119 {
 120         return (ENXIO);
 121 }
 122
 123 /*
 124  * Close always succeeds, and does not warn or panic if v_opencount or
 125  * v_writecount is incorrect, because a forced unmount or revocation
 126  * might have closed the file out from under the descriptor.
 127  */
 128 static int
 129 dead_close(struct vop_close_args *ap)
 130 {
 131         struct vnode *vp = ap->a_vp;
 132
 133         if (vp->v_opencount > 0) {
 134                 if ((ap->a_fflag & FWRITE) && vp->v_writecount > 0)
 135                         --vp->v_writecount;
 136                 --vp->v_opencount;
 137         }
 138         return (0);
 139 }
 140
 141 /*
 142  * Vnode op for read
 143  *
 144  * dead_read(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
 145  *           struct ucred *a_cred)
 146  */
 147 /* ARGSUSED */
 148 static int
 149 dead_read(struct vop_read_args *ap)
 150 {
 151         /*
 152          * Return EOF for tty devices, EIO for others
 153          */
 154         if ((ap->a_vp->v_flag & VISTTY) == 0)
 155                 return (EIO);
 156         return (0);
 157 }
 158
 159 /*
 160  * Vnode op for write
 161  *
 162  * dead_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
 163  *            struct ucred *a_cred)
 164  */
 165 /* ARGSUSED */
 166 static int
 167 dead_write(struct vop_write_args *ap)
 168 {
 169         return (EIO);
 170 }
 171
 172 /*
 173  * Device ioctl operation.
 174  *
 175  * dead_ioctl(struct vnode *a_vp, int a_command, caddr_t a_data, int a_fflag,
 176  *            struct ucred *a_cred, struct proc *a_p)
 177  */
 178 /* ARGSUSED */
 179 static int
 180 dead_ioctl(struct vop_ioctl_args *ap)
 181 {
 182         return (ENOTTY);
 183 }
 184
 185 /*
 186  * Wait until the vnode has finished changing state.
 187  *
 188  * dead_bmap(struct vnode *a_vp, off_t a_loffset,
 189  *           off_t *a_doffsetp, int *a_runp, int *a_runb)
 190  */
 191 static int
 192 dead_bmap(struct vop_bmap_args *ap)
 193 {
 194         return (EIO);
 195 }
 196
 197 /*
 198  * Print out the contents of a dead vnode.
 199  *
 200  * dead_print(struct vnode *a_vp)
 201  */
 202 /* ARGSUSED */
 203 static int
 204 dead_print(struct vop_print_args *ap)
 205 {
 206         kprintf("tag VT_NON, dead vnode\n");
 207         return (0);
 208 }
 209
 210 /*
 211  * Empty vnode bad operation
 212  */
 213 static int
 214 dead_badop(void)
 215 {
 216         panic("dead_badop called");
 217         /* NOTREACHED */
 218 }
 219
 220 /*
 221  * Trivial poll routine that always returns POLLHUP.
 222  * This is necessary so that a process which is polling a file
 223  * gets notified when that file is revoke()d.
 224  */
 225 static int
 226 dead_poll(struct vop_poll_args *ap)
 227 {
 228         return (POLLHUP);
 229 }