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/*-
* Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/bio.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <geom/geom.h>
#define G_ZERO_CLASS_NAME "ZERO"
SYSCTL_DECL(_kern_geom);
SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW, 0, "GEOM_ZERO stuff");
static int g_zero_clear = 1;
SYSCTL_INT(_kern_geom_zero, OID_AUTO, clear, CTLFLAG_RW, &g_zero_clear, 0,
"Clear read data buffer");
static int g_zero_byte = 0;
SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RW, &g_zero_byte, 0,
"Byte (octet) value to clear the buffers with");
static void
g_zero_start(struct bio *bp)
{
int error = ENXIO;
switch (bp->bio_cmd) {
case BIO_READ:
if (g_zero_clear)
memset(bp->bio_data, g_zero_byte, bp->bio_length);
/* FALLTHROUGH */
case BIO_DELETE:
case BIO_WRITE:
bp->bio_completed = bp->bio_length;
error = 0;
break;
case BIO_GETATTR:
default:
error = EOPNOTSUPP;
break;
}
g_io_deliver(bp, error);
}
static void
g_zero_init(struct g_class *mp)
{
struct g_geom *gp;
struct g_provider *pp;
g_topology_assert();
gp = g_new_geomf(mp, "gzero");
gp->start = g_zero_start;
gp->access = g_std_access;
pp = g_new_providerf(gp, "%s", gp->name);
pp->mediasize = 1152921504606846976LLU;
pp->sectorsize = 512;
g_error_provider(pp, 0);
}
static int
g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused,
struct g_geom *gp)
{
struct g_provider *pp;
g_topology_assert();
if (gp == NULL)
return (0);
pp = LIST_FIRST(&gp->provider);
if (pp == NULL)
return (0);
if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0)
return (EBUSY);
g_wither_geom(gp, ENXIO);
return (EBUSY);
}
static struct g_class g_zero_class = {
.name = G_ZERO_CLASS_NAME,
.version = G_VERSION,
.init = g_zero_init,
.destroy_geom = g_zero_destroy_geom
};
DECLARE_GEOM_CLASS(g_zero_class, g_zero);
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