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/*
*****************************************************************************
*
* File: fko_rand_value.c
*
* Author: Damien S. Stuart
*
* Purpose: Generate a 16-byte random numeric value.
*
* Copyright 2009-2013 Damien Stuart (dstuart@dstuart.org)
*
* License (GNU Public License):
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*
*****************************************************************************
*/
#include "fko_common.h"
#include "fko.h"
#ifdef WIN32
#include <sys/timeb.h>
#include <time.h>
#else
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#ifdef TIME_WITH_SYS_TIME
#include <time.h>
#endif
#endif
#define RAND_FILE "/dev/urandom"
#endif
/* Set/Generate the SPA data random value string.
*/
int
fko_set_rand_value(fko_ctx_t ctx, const char * const new_val)
{
#ifdef WIN32
struct _timeb tb;
#else
FILE *rfd;
struct timeval tv;
size_t amt_read;
#endif
unsigned long seed;
char *tmp_buf;
/* Context must be initialized.
*/
if(!CTX_INITIALIZED(ctx))
return FKO_ERROR_CTX_NOT_INITIALIZED;
/* If a valid value was given, use it and return happy.
*/
if(new_val != NULL)
{
if(strnlen(new_val, FKO_RAND_VAL_SIZE+1) != FKO_RAND_VAL_SIZE)
return(FKO_ERROR_INVALID_DATA);
if(ctx->rand_val != NULL)
free(ctx->rand_val);
ctx->rand_val = strdup(new_val);
if(ctx->rand_val == NULL)
return(FKO_ERROR_MEMORY_ALLOCATION);
ctx->state |= FKO_DATA_MODIFIED;
return(FKO_SUCCESS);
}
#ifdef WIN32
_ftime_s(&tb);
seed = ((tb.time * 1000) + tb.millitm) & 0xFFFFFFFF;
#else
/* Attempt to read seed data from /dev/urandom. If that does not
* work, then fall back to a time-based method (less secure, but
* probably more portable).
*/
if((rfd = fopen(RAND_FILE, "r")) != NULL)
{
/* Read seed from /dev/urandom
*/
amt_read = fread(&seed, 4, 1, rfd);
fclose(rfd);
if (amt_read != 1)
return(FKO_ERROR_FILESYSTEM_OPERATION);
}
else
{
/* Seed based on time (current usecs).
*/
gettimeofday(&tv, NULL);
seed = tv.tv_usec;
}
#endif
srand(seed);
if(ctx->rand_val != NULL)
free(ctx->rand_val);
ctx->rand_val = malloc(FKO_RAND_VAL_SIZE+1);
if(ctx->rand_val == NULL)
return(FKO_ERROR_MEMORY_ALLOCATION);
memset(ctx->rand_val, 0, FKO_RAND_VAL_SIZE+1);
tmp_buf = malloc(FKO_RAND_VAL_SIZE+1);
if(tmp_buf == NULL)
return(FKO_ERROR_MEMORY_ALLOCATION);
memset(tmp_buf, 0, FKO_RAND_VAL_SIZE+1);
snprintf(ctx->rand_val, FKO_RAND_VAL_SIZE, "%u", rand());
while(strnlen(ctx->rand_val, FKO_RAND_VAL_SIZE+1) < FKO_RAND_VAL_SIZE)
{
snprintf(tmp_buf, FKO_RAND_VAL_SIZE, "%u", rand());
strlcat(ctx->rand_val, tmp_buf, FKO_RAND_VAL_SIZE+1);
}
free(tmp_buf);
ctx->state |= FKO_DATA_MODIFIED;
return(FKO_SUCCESS);
}
/* Return the current rand value.
*/
int
fko_get_rand_value(fko_ctx_t ctx, char **rand_value)
{
/* Must be initialized
*/
if(!CTX_INITIALIZED(ctx))
return(FKO_ERROR_CTX_NOT_INITIALIZED);
*rand_value = ctx->rand_val;
return(FKO_SUCCESS);
}
/***EOF***/
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