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/**
* @file randomizer.c
*
* @brief Implementation of randomizer_t.
*
*/
/*
* Copyright (C) 2005-2006 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.
*/
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "randomizer.h"
typedef struct private_randomizer_t private_randomizer_t;
/**
* Private data of an randomizer_t object.
*/
struct private_randomizer_t {
/**
* Public randomizer_t interface.
*/
randomizer_t public;
/**
* @brief Reads a specific number of bytes from random or pseudo random device.
*
* @param this calling object
* @param pseudo_random TRUE, if from pseudo random bytes should be read,
* FALSE for true random bytes
* @param bytes number of bytes to read
* @param[out] buffer pointer to buffer where to write the data in.
* Size of buffer has to be at least bytes.
*/
status_t (*get_bytes_from_device) (private_randomizer_t *this,bool pseudo_random, size_t bytes, u_int8_t *buffer);
};
/**
* Implementation of private_randomizer_t.get_bytes_from_device.
*/
static status_t get_bytes_from_device(private_randomizer_t *this,bool pseudo_random, size_t bytes, u_int8_t *buffer)
{
size_t ndone;
int device;
size_t got;
char * device_name;
device_name = pseudo_random ? DEV_URANDOM : DEV_RANDOM;
device = open(device_name, 0);
if (device < 0) {
return FAILED;
}
ndone = 0;
/* read until nbytes are read */
while (ndone < bytes)
{
got = read(device, buffer + ndone, bytes - ndone);
if (got <= 0) {
close(device);
return FAILED;
}
ndone += got;
}
close(device);
return SUCCESS;
}
/**
* Implementation of randomizer_t.get_random_bytes.
*/
static status_t get_random_bytes(private_randomizer_t *this,size_t bytes, u_int8_t *buffer)
{
return this->get_bytes_from_device(this, FALSE, bytes, buffer);
}
/**
* Implementation of randomizer_t.allocate_random_bytes.
*/
static status_t allocate_random_bytes(private_randomizer_t *this, size_t bytes, chunk_t *chunk)
{
status_t status;
chunk->len = bytes;
chunk->ptr = malloc(bytes);
status = this->get_bytes_from_device(this, FALSE, bytes, chunk->ptr);
if (status != SUCCESS)
{
free(chunk->ptr);
}
return status;
}
/**
* Implementation of randomizer_t.get_pseudo_random_bytes.
*/
static status_t get_pseudo_random_bytes(private_randomizer_t *this,size_t bytes, u_int8_t *buffer)
{
return (this->get_bytes_from_device(this, TRUE, bytes, buffer));
}
/**
* Implementation of randomizer_t.allocate_pseudo_random_bytes.
*/
static status_t allocate_pseudo_random_bytes(private_randomizer_t *this, size_t bytes, chunk_t *chunk)
{
status_t status;
chunk->len = bytes;
chunk->ptr = malloc(bytes);
status = this->get_bytes_from_device(this, TRUE, bytes, chunk->ptr);
if (status != SUCCESS)
{
free(chunk->ptr);
}
return status;
}
/**
* Implementation of randomizer_t.destroy.
*/
static void destroy(private_randomizer_t *this)
{
free(this);
}
/*
* Described in header.
*/
randomizer_t *randomizer_create(void)
{
private_randomizer_t *this = malloc_thing(private_randomizer_t);
/* public functions */
this->public.get_random_bytes = (status_t (*) (randomizer_t *,size_t, u_int8_t *)) get_random_bytes;
this->public.allocate_random_bytes = (status_t (*) (randomizer_t *,size_t, chunk_t *)) allocate_random_bytes;
this->public.get_pseudo_random_bytes = (status_t (*) (randomizer_t *,size_t, u_int8_t *)) get_pseudo_random_bytes;
this->public.allocate_pseudo_random_bytes = (status_t (*) (randomizer_t *,size_t, chunk_t *)) allocate_pseudo_random_bytes;
this->public.destroy = (void (*) (randomizer_t *))destroy;
/* private functions */
this->get_bytes_from_device = get_bytes_from_device;
return &(this->public);
}
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