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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 <unistd.h>
#include <time.h>
#include <libnbd.h>
#include "random.h"
#define SIZE 1024*1024
static char data[SIZE];
static unsigned histogram[256];
/* After reading the whole disk above, we then read randomly selected
* subsets of the disk and compare the data (it should be identical).
*/
#define RSIZE 10240
#define NR_READS 50
static char rdata[RSIZE];
int
main (int argc, char *argv[])
{
struct nbd_handle *nbd;
struct random_state random_state;
int i;
unsigned offset;
char sizearg[32];
nbd = nbd_create ();
if (nbd == NULL) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
snprintf (sizearg, sizeof sizearg, "%d", SIZE);
if (nbd_connect_command (nbd,
(char *[]) {
"nbdkit", "-s", "--exit-with-parent",
"random", sizearg,
NULL }) == -1) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
/* Read the whole device. */
if (nbd_pread (nbd, data, sizeof data, 0, 0) == -1) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
/* Test that the data is sufficiently random using a simple
* histogram. This just tests for gross errors and is not a
* complete statistical study.
*/
for (i = 0; i < SIZE; ++i) {
unsigned char c = (unsigned char) data[i];
histogram[c]++;
}
for (i = 0; i < 256; ++i) {
const unsigned expected = SIZE / 256;
if (histogram[i] < 80 * expected / 100) {
fprintf (stderr, "test-random: "
"random data is not uniformly distributed\n"
"eg. byte %d occurs %u times (expected about %u times)\n",
i, histogram[i], expected);
exit (EXIT_FAILURE);
}
}
/* Randomly read parts of the disk to ensure we get the same data.
*/
xsrandom (time (NULL), &random_state);
for (i = 0; i < NR_READS; ++i) {
offset = xrandom (&random_state);
offset %= SIZE - RSIZE;
if (nbd_pread (nbd, rdata, sizeof rdata, offset, 0) == -1) {
fprintf (stderr, "%s\n", nbd_get_error ());
exit (EXIT_FAILURE);
}
if (memcmp (&data[offset], rdata, RSIZE) != 0) {
fprintf (stderr, "test-random: returned different data\n");
exit (EXIT_FAILURE);
}
}
nbd_close (nbd);
exit (EXIT_SUCCESS);
}
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