/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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.
 * 3. 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.
 */

#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>

/*
 * Prototypes for dead operations on vnodes.
 */
static vop_lookup_t     dead_lookup;
static vop_open_t       dead_open;
static vop_close_t      dead_close;
static vop_getwritemount_t dead_getwritemount;
static vop_rename_t     dead_rename;
static vop_unset_text_t dead_unset_text;

struct vop_vector dead_vnodeops = {
        .vop_default =          &default_vnodeops,

        .vop_access =           VOP_EBADF,
        .vop_advlock =          VOP_EBADF,
        .vop_bmap =             VOP_EBADF,
        .vop_close =            dead_close,
        .vop_create =           VOP_PANIC,
        .vop_delayed_setsize =  VOP_NULL,
        .vop_fplookup_symlink = VOP_EOPNOTSUPP,
        .vop_fplookup_vexec =   VOP_EOPNOTSUPP,
        .vop_getattr =          VOP_EBADF,
        .vop_getwritemount =    dead_getwritemount,
        .vop_inactive =         VOP_NULL,
        .vop_ioctl =            VOP_EBADF,
        .vop_link =             VOP_PANIC,
        .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 =           dead_rename,
        .vop_rmdir =            VOP_PANIC,
        .vop_setattr =          VOP_EBADF,
        .vop_symlink =          VOP_PANIC,
        .vop_vptocnp =          VOP_EBADF,
        .vop_unset_text =       dead_unset_text,
        .vop_write =            dead_write,
};
VFS_VOP_VECTOR_REGISTER(dead_vnodeops);

static int
dead_getwritemount(struct vop_getwritemount_args *ap)
{

        *(ap->a_mpp) = NULL;
        return (0);
}

/*
 * Trivial lookup routine that always fails.
 */
static int
dead_lookup(struct vop_lookup_args *ap)
{

        *ap->a_vpp = NULL;
        return (ENOTDIR);
}

/*
 * Silently succeed open and close.
 */
static int
dead_open(struct vop_open_args *ap)
{
        return (0);
}

static int
dead_close(struct vop_close_args *ap)
{
        return (0);
}

int
dead_read(struct vop_read_args *ap)
{

        /*
         * Return EOF for tty devices, ENXIO for others
         */
        if (ap->a_vp->v_vflag & VV_ISTTY)
                return (0);
        return (ENXIO);
}

int
dead_write(struct vop_write_args *ap)
{

        return (ENXIO);
}

int
dead_poll(struct vop_poll_args *ap)
{

        if (ap->a_events & ~POLLSTANDARD)
                return (POLLNVAL);

        /*
         * Let the user find out that the descriptor is gone.
         */
        return (POLLHUP | ((POLLIN | POLLRDNORM) & ap->a_events));

}

static int
dead_rename(struct vop_rename_args *ap)
{

        vop_rename_fail(ap);
        return (EXDEV);
}

static int
dead_unset_text(struct vop_unset_text_args *ap)
{

        return (0);
}