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/*
Licensed under the GNU Public License.
Copyright (C) 1998-2009 by Thomas M. Vier, Jr. All Rights Reserved.
wipe is free software.
See LICENSE for more information.
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.
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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "config.h"
#include "std.h"
#include "io.h"
#include "mt.h"
#include "main.h"
#include "rand.h"
extern char *argvzero;
extern int errno, exit_code;
extern struct opt_s options;
int entropyfd;
char entropy_name[13]; /* for do_read error reporting */
/*
rand_init -- inits the entropy source file descriptor
*/
public int rand_init(void)
{
/* try /dev/urandom first; if that fails, try /dev/random */
if ((entropyfd = open("/dev/urandom", O_RDONLY)) < 0)
{
if ((entropyfd = open("/dev/random", O_RDONLY)) < 0)
{
fprintf(stderr, "\r%s: cannot open entropy source: %s\n",
argvzero, strerror(errno));
exit(1);
}
else
{
strncpy(entropy_name, "/dev/random", sizeof(entropy_name));
fprintf(stderr, "\r%s: warning: cannot open /dev/urandom, "
"using /dev/random instead\n", argvzero);
}
}
else
strncpy(entropy_name, "/dev/urandom", sizeof(entropy_name));
/* we must seed once at least regardless of seclevel --tg */
if (prng_seed())
return FAILED;
return 0;
}
/*** the following functions are PRNG dependent ***/
/*
prng_seed -- init seed
*/
public int prng_seed(void)
{
u_rand_t seed;
if (do_read(entropy_name, entropyfd, &seed, sizeof(prng_seed)))
return FAILED;
seedMT(seed);
return 0;
}
/*
prng_get_rand -- return u_rand_t PRN
*/
public u_rand_t prng_get_rand(void)
{
return randomMT();
}
/*
prng_fillbuf -- fills a buffer with pseudo-random values
the buffer must be u_rand_t aligned
*/
public void prng_fillbuf(const int seclevel, u_rand_t *buf, const size_t size)
{
int i, ii;
u_rand_t rand;
unsigned char *cbuf, *randp;
i=0; ii = size / sizeof(u_rand_t);
while (i < ii)
buf[i++] = randomMT();
ii = size % sizeof(u_rand_t);
if (ii)
{
rand = randomMT();
cbuf = (unsigned char *) ((void *) buf + (size - ii));
randp = (unsigned char *) &rand;
i=0;
while (i < ii)
{
cbuf[i] = randp[i];
i++;
}
}
}
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