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/* nbdkit
* Copyright Red Hat
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * 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.
*
* * Neither the name of Red Hat 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 RED HAT 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 RED HAT 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 <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <string.h>
#include <nbdkit-filter.h>
#include "cleanup.h"
static int64_t offset = 0, range = -1;
/* Called for each key=value passed on the command line. */
static int
offset_config (nbdkit_next_config *next, nbdkit_backend *nxdata,
const char *key, const char *value)
{
if (strcmp (key, "offset") == 0) {
offset = nbdkit_parse_size (value);
if (offset == -1)
return -1;
return 0;
}
else if (strcmp (key, "range") == 0) {
range = nbdkit_parse_size (value);
if (range == -1)
return -1;
return 0;
}
else
return next (nxdata, key, value);
}
#define offset_config_help \
"offset=<OFFSET> The start offset to serve (default 0).\n" \
"range=<LENGTH> The total size to serve (default rest of file)."
/* Get the file size. */
static int64_t
offset_get_size (nbdkit_next *next,
void *handle)
{
int64_t real_size = next->get_size (next);
if (real_size == -1)
return -1;
if (range >= 0) {
if (offset > real_size - range) {
nbdkit_error ("offset+range (%" PRIi64 "+%" PRIi64 ") "
"is larger than the real size (%" PRIi64 ") "
"of the underlying file or device",
offset, range, real_size);
return -1;
}
return range;
}
else if (offset > real_size) {
nbdkit_error ("offset (%" PRIi64 ") "
"is larger than the real size (%" PRIi64 ") "
"of the underlying file or device",
offset, real_size);
return -1;
}
else
return real_size - offset;
}
/* Read data. */
static int
offset_pread (nbdkit_next *next,
void *handle, void *buf, uint32_t count, uint64_t offs,
uint32_t flags, int *err)
{
return next->pread (next, buf, count, offs + offset, flags, err);
}
/* Write data. */
static int
offset_pwrite (nbdkit_next *next,
void *handle,
const void *buf, uint32_t count, uint64_t offs, uint32_t flags,
int *err)
{
return next->pwrite (next, buf, count, offs + offset, flags, err);
}
/* Trim data. */
static int
offset_trim (nbdkit_next *next,
void *handle, uint32_t count, uint64_t offs, uint32_t flags,
int *err)
{
return next->trim (next, count, offs + offset, flags, err);
}
/* Zero data. */
static int
offset_zero (nbdkit_next *next,
void *handle, uint32_t count, uint64_t offs, uint32_t flags,
int *err)
{
return next->zero (next, count, offs + offset, flags, err);
}
/* Extents. */
static int
offset_extents (nbdkit_next *next,
void *handle, uint32_t count, uint64_t offs, uint32_t flags,
struct nbdkit_extents *extents, int *err)
{
size_t i;
CLEANUP_EXTENTS_FREE struct nbdkit_extents *extents2 = NULL;
struct nbdkit_extent e;
int64_t end = range >= 0 ? offset + range : next->get_size (next);
extents2 = nbdkit_extents_new (offs + offset, end);
if (extents2 == NULL) {
*err = errno;
return -1;
}
if (next->extents (next, count, offs + offset, flags, extents2, err) == -1)
return -1;
for (i = 0; i < nbdkit_extents_count (extents2); ++i) {
e = nbdkit_get_extent (extents2, i);
e.offset -= offset;
if (nbdkit_add_extent (extents, e.offset, e.length, e.type) == -1) {
*err = errno;
return -1;
}
}
return 0;
}
/* Cache data. */
static int
offset_cache (nbdkit_next *next,
void *handle, uint32_t count, uint64_t offs, uint32_t flags,
int *err)
{
return next->cache (next, count, offs + offset, flags, err);
}
static struct nbdkit_filter filter = {
.name = "offset",
.longname = "nbdkit offset filter",
.config = offset_config,
.config_help = offset_config_help,
.get_size = offset_get_size,
.pread = offset_pread,
.pwrite = offset_pwrite,
.trim = offset_trim,
.zero = offset_zero,
.extents = offset_extents,
.cache = offset_cache,
};
NBDKIT_REGISTER_FILTER (filter)
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