openssl/test/testutil/random.c
Pauli e9a5932d04 Add weak platform independent PRNG to test framework.
Implement the GNU C library's random(3) pseudorandom number generator.
The algorithm is described: https://www.mscs.dal.ca/~selinger/random/

The rationale is to make the tests repeatable across differing platforms with
different underlying implementations of the random(3) library call.

More specifically: when executing tests with random ordering.

[extended tests]

Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/9463)
2019-07-29 09:11:15 +10:00

41 lines
1.1 KiB
C

/*
* Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "../testutil.h"
/*
* This is an implementation of the algorithm used by the GNU C library's
* random(3) pseudorandom number generator as described:
* https://www.mscs.dal.ca/~selinger/random/
*/
static uint32_t test_random_state[31];
uint32_t test_random(void) {
static unsigned int pos = 3;
if (pos == 31)
pos = 0;
test_random_state[pos] += test_random_state[(pos + 28) % 31];
return test_random_state[pos++] / 2;
}
void test_random_seed(uint32_t sd) {
int i;
int32_t s;
const unsigned int mod = (1u << 31) - 1;
test_random_state[0] = sd;
for (i = 1; i < 31; i++) {
s = (int32_t)test_random_state[i - 1];
test_random_state[i] = (uint32_t)((16807 * (int64_t)s) % mod);
}
for (i = 34; i < 344; i++)
test_random();
}