freebsd-dev/sys/fs/deadfs/dead_vnops.c
Poul-Henning Kamp aec0fb7b40 Back when VOP_* was introduced, we did not have new-style struct
initializations but we did have lofty goals and big ideals.

Adjust to more contemporary circumstances and gain type checking.

	Replace the entire vop_t frobbing thing with properly typed
	structures.  The only casualty is that we can not add a new
	VOP_ method with a loadable module.  History has not given
	us reason to belive this would ever be feasible in the the
	first place.

	Eliminate in toto VOCALL(), vop_t, VNODEOP_SET() etc.

	Give coda correct prototypes and function definitions for
	all vop_()s.

	Generate a bit more data from the vnode_if.src file:  a
	struct vop_vector and protype typedefs for all vop methods.

	Add a new vop_bypass() and make vop_default be a pointer
	to another struct vop_vector.

	Remove a lot of vfs_init since vop_vector is ready to use
	from the compiler.

	Cast various vop_mumble() to void * with uppercase name,
	for instance VOP_PANIC, VOP_NULL etc.

	Implement VCALL() by making vdesc_offset the offsetof() the
	relevant function pointer in vop_vector.  This is disgusting
	but since the code is generated by a script comparatively
	safe.  The alternative for nullfs etc. would be much worse.

	Fix up all vnode method vectors to remove casts so they
	become typesafe.  (The bulk of this is generated by scripts)
2004-12-01 23:16:38 +00:00

260 lines
5.8 KiB
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
* $FreeBSD$
*/
#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 vop_bmap_t dead_bmap;
static vop_ioctl_t dead_ioctl;
static vop_lock_t dead_lock;
static vop_lookup_t dead_lookup;
static vop_open_t dead_open;
static vop_poll_t dead_poll;
static vop_read_t dead_read;
static vop_write_t dead_write;
struct vop_vector dead_vnodeops = {
.vop_default = &default_vnodeops,
.vop_access = VOP_EBADF,
.vop_advlock = VOP_EBADF,
.vop_bmap = dead_bmap,
.vop_create = VOP_PANIC,
.vop_getattr = VOP_EBADF,
.vop_inactive = VOP_NULL,
.vop_ioctl = dead_ioctl,
.vop_link = VOP_PANIC,
.vop_lock = dead_lock,
.vop_lookup = dead_lookup,
.vop_mkdir = VOP_PANIC,
.vop_mknod = VOP_PANIC,
.vop_open = dead_open,
.vop_pathconf = VOP_EBADF, /* per pathconf(2) */
.vop_poll = dead_poll,
.vop_read = dead_read,
.vop_readdir = VOP_EBADF,
.vop_readlink = VOP_EBADF,
.vop_reclaim = VOP_NULL,
.vop_remove = VOP_PANIC,
.vop_rename = VOP_PANIC,
.vop_rmdir = VOP_PANIC,
.vop_setattr = VOP_EBADF,
.vop_symlink = VOP_PANIC,
.vop_write = dead_write,
};
/*
* 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 bufobj **a_bop;
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_bop, 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);
}