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/* NBD client library in userspace.
* Copyright Red Hat
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <errno.h>
#include "nbdcopy.h"
/* This sinks writes and aborts on any read-like operations. It
* should be faster than using /dev/null because it "supports" fast
* zeroing.
*/
static struct rw_ops null_ops;
struct rw_null {
struct rw rw;
};
struct rw *
null_create (const char *name)
{
struct rw_null *rw = calloc (1, sizeof *rw);
if (rw == NULL) { perror ("calloc"); exit (EXIT_FAILURE); }
rw->rw.ops = &null_ops;
rw->rw.name = name;
rw->rw.size = INT64_MAX;
rw->rw.preferred = 4096;
return &rw->rw;
}
static void
null_close (struct rw *rw)
{
free (rw);
}
static void
null_flush (struct rw *rw)
{
/* nothing */
}
static bool
null_is_read_only (struct rw *rw)
{
return false;
}
static bool
null_can_extents (struct rw *rw)
{
return false;
}
static bool
null_can_multi_conn (struct rw *rw)
{
return true;
}
static void
null_start_multi_conn (struct rw *rw)
{
/* nothing */
}
static size_t
null_synch_read (struct rw *rw,
void *data, size_t len, uint64_t offset)
{
abort ();
}
static void
null_synch_write (struct rw *rw,
const void *data, size_t len, uint64_t offset)
{
/* nothing */
}
static bool
null_synch_zero (struct rw *rw, uint64_t offset, uint64_t count, bool allocate)
{
return true;
}
static void
null_asynch_read (struct rw *rw,
struct command *command,
nbd_completion_callback cb)
{
abort ();
}
static void
null_asynch_write (struct rw *rw,
struct command *command,
nbd_completion_callback cb)
{
int dummy = 0;
cb.callback (cb.user_data, &dummy);
}
static bool
null_asynch_zero (struct rw *rw, struct command *command,
nbd_completion_callback cb, bool allocate)
{
int dummy = 0;
cb.callback (cb.user_data, &dummy);
return true;
}
static unsigned
null_in_flight (struct rw *rw, size_t index)
{
return 0;
}
static void
null_get_extents (struct rw *rw, size_t index,
uint64_t offset, uint64_t count,
extent_list *ret)
{
abort ();
}
static struct rw_ops null_ops = {
.ops_name = "null_ops",
.close = null_close,
.is_read_only = null_is_read_only,
.can_extents = null_can_extents,
.can_multi_conn = null_can_multi_conn,
.start_multi_conn = null_start_multi_conn,
.flush = null_flush,
.synch_read = null_synch_read,
.synch_write = null_synch_write,
.synch_zero = null_synch_zero,
.asynch_read = null_asynch_read,
.asynch_write = null_asynch_write,
.asynch_zero = null_asynch_zero,
.in_flight = null_in_flight,
.get_polling_fd = get_polling_fd_not_supported,
.asynch_notify_read = asynch_notify_read_write_not_supported,
.asynch_notify_write = asynch_notify_read_write_not_supported,
.get_extents = null_get_extents,
};
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