FreeBSD-5.3/sys/fs/deadfs/dead_vnops.c
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)dead_vnops.c 8.1 (Berkeley) 6/10/93
* $FreeBSD: src/sys/fs/deadfs/dead_vnops.c,v 1.40 2004/04/07 20:45:59 imp Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/poll.h>
#include <sys/vnode.h>
static int chkvnlock(struct vnode *);
/*
* Prototypes for dead operations on vnodes.
*/
static int dead_bmap(struct vop_bmap_args *);
static int dead_ioctl(struct vop_ioctl_args *);
static int dead_lock(struct vop_lock_args *);
static int dead_lookup(struct vop_lookup_args *);
static int dead_open(struct vop_open_args *);
static int dead_poll(struct vop_poll_args *);
static int dead_read(struct vop_read_args *);
static int dead_write(struct vop_write_args *);
vop_t **dead_vnodeop_p;
static struct vnodeopv_entry_desc dead_vnodeop_entries[] = {
{ &vop_default_desc, (vop_t *) vop_defaultop },
{ &vop_access_desc, (vop_t *) vop_ebadf },
{ &vop_advlock_desc, (vop_t *) vop_ebadf },
{ &vop_bmap_desc, (vop_t *) dead_bmap },
{ &vop_create_desc, (vop_t *) vop_panic },
{ &vop_getattr_desc, (vop_t *) vop_ebadf },
{ &vop_inactive_desc, (vop_t *) vop_null },
{ &vop_ioctl_desc, (vop_t *) dead_ioctl },
{ &vop_link_desc, (vop_t *) vop_panic },
{ &vop_lock_desc, (vop_t *) dead_lock },
{ &vop_lookup_desc, (vop_t *) dead_lookup },
{ &vop_mkdir_desc, (vop_t *) vop_panic },
{ &vop_mknod_desc, (vop_t *) vop_panic },
{ &vop_open_desc, (vop_t *) dead_open },
{ &vop_pathconf_desc, (vop_t *) vop_ebadf }, /* per pathconf(2) */
{ &vop_poll_desc, (vop_t *) dead_poll },
{ &vop_read_desc, (vop_t *) dead_read },
{ &vop_readdir_desc, (vop_t *) vop_ebadf },
{ &vop_readlink_desc, (vop_t *) vop_ebadf },
{ &vop_reclaim_desc, (vop_t *) vop_null },
{ &vop_remove_desc, (vop_t *) vop_panic },
{ &vop_rename_desc, (vop_t *) vop_panic },
{ &vop_rmdir_desc, (vop_t *) vop_panic },
{ &vop_setattr_desc, (vop_t *) vop_ebadf },
{ &vop_symlink_desc, (vop_t *) vop_panic },
{ &vop_write_desc, (vop_t *) dead_write },
{ NULL, NULL }
};
static struct vnodeopv_desc dead_vnodeop_opv_desc =
{ &dead_vnodeop_p, dead_vnodeop_entries };
VNODEOP_SET(dead_vnodeop_opv_desc);
/*
* Trivial lookup routine that always fails.
*/
/* ARGSUSED */
static int
dead_lookup(ap)
struct vop_lookup_args /* {
struct vnode * a_dvp;
struct vnode ** a_vpp;
struct componentname * a_cnp;
} */ *ap;
{
*ap->a_vpp = NULL;
return (ENOTDIR);
}
/*
* Open always fails as if device did not exist.
*/
/* ARGSUSED */
static int
dead_open(ap)
struct vop_open_args /* {
struct vnode *a_vp;
int a_mode;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
return (ENXIO);
}
/*
* Vnode op for read
*/
/* ARGSUSED */
static int
dead_read(ap)
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
if (chkvnlock(ap->a_vp))
panic("dead_read: lock");
/*
* Return EOF for tty devices, EIO for others
*/
if ((ap->a_vp->v_vflag & VV_ISTTY) == 0)
return (EIO);
return (0);
}
/*
* Vnode op for write
*/
/* ARGSUSED */
static int
dead_write(ap)
struct vop_write_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
if (chkvnlock(ap->a_vp))
panic("dead_write: lock");
return (EIO);
}
/*
* Device ioctl operation.
*/
/* ARGSUSED */
static int
dead_ioctl(ap)
struct vop_ioctl_args /* {
struct vnode *a_vp;
u_long a_command;
caddr_t a_data;
int a_fflag;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
if (!chkvnlock(ap->a_vp))
return (ENOTTY);
/* XXX: Doesn't this just recurse back here ? */
return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap));
}
/*
* Wait until the vnode has finished changing state.
*/
static int
dead_lock(ap)
struct vop_lock_args /* {
struct vnode *a_vp;
int a_flags;
struct proc *a_p;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
/*
* Since we are not using the lock manager, we must clear
* the interlock here.
*/
if (ap->a_flags & LK_INTERLOCK) {
mtx_unlock(&vp->v_interlock);
ap->a_flags &= ~LK_INTERLOCK;
}
if (!chkvnlock(vp))
return (0);
return (VCALL(vp, VOFFSET(vop_lock), ap));
}
/*
* Wait until the vnode has finished changing state.
*/
static int
dead_bmap(ap)
struct vop_bmap_args /* {
struct vnode *a_vp;
daddr_t a_bn;
struct vnode **a_vpp;
daddr_t *a_bnp;
int *a_runp;
int *a_runb;
} */ *ap;
{
if (!chkvnlock(ap->a_vp))
return (EIO);
return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp, ap->a_runb));
}
/*
* We have to wait during times when the vnode is
* in a state of change.
*/
static int
chkvnlock(vp)
register struct vnode *vp;
{
int locked = 0;
VI_LOCK(vp);
while (vp->v_iflag & VI_XLOCK) {
vp->v_iflag |= VI_XWANT;
(void) msleep((caddr_t)vp, VI_MTX(vp), PINOD, "ckvnlk", 0);
locked = 1;
}
VI_UNLOCK(vp);
return (locked);
}
/*
* Trivial poll routine that always returns POLLHUP.
* This is necessary so that a process which is polling a file
* gets notified when that file is revoke()d.
*/
static int
dead_poll(ap)
struct vop_poll_args *ap;
{
return (POLLHUP);
}