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/****************************************************************************
* examples/random/random_main.c
*
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 NuttX 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 COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <debug.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
#ifndef CONFIG_EXAMPLES_MAXSAMPLES
# define CONFIG_EXAMPLES_MAXSAMPLES 64
#endif
#ifndef CONFIG_EXAMPLES_NSAMPLES
# define CONFIG_EXAMPLES_NSAMPLES 8
#endif
#if CONFIG_EXAMPLES_NSAMPLES > CONFIG_EXAMPLES_MAXSAMPLES
# warning CONFIG_EXAMPLES_NSAMPLES > CONFIG_EXAMPLES_MAXSAMPLES
# undef CONFIG_EXAMPLES_NSAMPLES
# define CONFIG_EXAMPLES_NSAMPLES CONFIG_EXAMPLES_MAXSAMPLES
#endif
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* rand_main
****************************************************************************/
int rand_main(int argc, char *argv[])
{
uint32_t buffer[CONFIG_EXAMPLES_MAXSAMPLES];
int nsamples = CONFIG_EXAMPLES_NSAMPLES;
ssize_t nread;
int fd;
/* One argument is possible... the number of samples to collect */
if (argc > 1)
{
nsamples = atoi(argv[1]);
}
/* Clip the numer of samples to the configured buffer size */
if (nsamples > CONFIG_EXAMPLES_MAXSAMPLES)
{
nsamples = CONFIG_EXAMPLES_MAXSAMPLES;
}
/* Open /dev/random */
fd = open("/dev/random", O_RDONLY);
if (fd < 0)
{
int errcode = errno;
fprintf(stderr, "ERROR: Failed to open /dev/random: %d\n", errcode);
exit(EXIT_FAILURE);
}
/* Read the requested number of samples */
printf("Reading %d random numbers\n", nsamples);
nread = read(fd, buffer, nsamples * sizeof(uint32_t));
if (nread < 0)
{
int errcode = errno;
fprintf(stderr, "ERROR: Read from /dev/randon failed: %d\n", errcode);
(void)close(fd);
exit(EXIT_FAILURE);
}
/* Dump the sample buffer */
lib_dumpbuffer("Random values", (FAR const uint8_t*)buffer, nread);
(void)close(fd);
return EXIT_SUCCESS;
}
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