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/*
* Copyright (C) 2005-2008 Martin Willi
* Copyright (C) 2005 Jan Hutter
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program 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 General Public License
* for more details.
*
* $Id$
*/
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <debug.h>
#include "random_rng.h"
#ifndef DEV_RANDOM
# define DEV_RANDOM "/dev/random"
#endif
#ifndef DEV_URANDOM
# define DEV_URANDOM "/dev/urandom"
#endif
typedef struct private_random_rng_t private_random_rng_t;
/**
* Private data of an random_rng_t object.
*/
struct private_random_rng_t {
/**
* Public random_rng_t interface.
*/
random_rng_t public;
/**
* random device, depends on quality
*/
int dev;
/**
* file we read random bytes from
*/
char *file;
};
/**
* Implementation of random_rng_t.get_bytes.
*/
static void get_bytes(private_random_rng_t *this, size_t bytes,
u_int8_t *buffer)
{
size_t done, got;
done = 0;
while (done < bytes)
{
got = read(this->dev, buffer + done, bytes - done);
if (got <= 0)
{
DBG1("reading from \"%s\" failed: %s, retrying...",
this->file, strerror(errno));
close(this->dev);
sleep(1);
this->dev = open(this->file, 0);
}
done += got;
}
}
/**
* Implementation of random_rng_t.allocate_bytes.
*/
static void allocate_bytes(private_random_rng_t *this, size_t bytes,
chunk_t *chunk)
{
*chunk = chunk_alloc(bytes);
get_bytes(this, chunk->len, chunk->ptr);
}
/**
* Implementation of random_rng_t.destroy.
*/
static void destroy(private_random_rng_t *this)
{
close(this->dev);
free(this);
}
/*
* Described in header.
*/
random_rng_t *random_rng_create(rng_quality_t quality)
{
private_random_rng_t *this = malloc_thing(private_random_rng_t);
/* public functions */
this->public.rng.get_bytes = (void (*) (rng_t *, size_t, u_int8_t*)) get_bytes;
this->public.rng.allocate_bytes = (void (*) (rng_t *, size_t, chunk_t*)) allocate_bytes;
this->public.rng.destroy = (void (*) (rng_t *))destroy;
if (quality == RNG_REAL)
{
this->file = DEV_RANDOM;
}
else
{
this->file = DEV_URANDOM;
}
this->dev = open(this->file, 0);
if (this->dev < 0)
{
DBG1("opening \"%s\" failed: %s", this->file, strerror(errno));
free(this);
return NULL;
}
return &this->public;
}
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