minix/lib/sysutil/get_randomness.c
Ben Gras 9647fbc94e moved type and constants for random data to include file;
added consistency check in random; added source of randomness
internal to random using timing; only retrieve random bins that are full.
2009-04-02 15:24:44 +00:00

34 lines
955 B
C

#include <lib.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <minix/profile.h>
#include <minix/syslib.h>
#include <minix/type.h>
#include <minix/sysutil.h>
/*===========================================================================*
* get_randomness *
*===========================================================================*/
PUBLIC void get_randomness(rand, source)
struct k_randomness *rand;
int source;
{
/* Use architecture-dependent high-resolution clock for
* raw entropy gathering.
*/
int r_next;
unsigned long tsc_high, tsc_low;
source %= RANDOM_SOURCES;
r_next= rand->bin[source].r_next;
read_tsc(&tsc_high, &tsc_low);
rand->bin[source].r_buf[r_next] = tsc_low;
if (rand->bin[source].r_size < RANDOM_ELEMENTS) {
rand->bin[source].r_size ++;
}
rand->bin[source].r_next = (r_next + 1 ) % RANDOM_ELEMENTS;
}