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/*-
* Copyright (c) 2006 Verdens Gang AS
* Copyright (c) 2006-2011 Varnish Software AS
* Copyright (c) 1983, 1993 The Regents of the University of California.
* All rights reserved.
*
* Author: Dag-Erling Smørgrav <des@des.no>
*
* SPDX-License-Identifier: BSD-2-Clause
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Partially from: $FreeBSD: head/lib/libc/stdlib/random.c 303342
*
*/
#include "config.h"
#include <fcntl.h>
#include <math.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "vdef.h"
#include "vas.h"
#include "vrnd.h"
vrnd_lock_f *VRND_Lock;
vrnd_lock_f *VRND_Unlock;
/**********************************************************************
* Stripped down random(3) implementation from FreeBSD, to provide
* predictable "random" numbers of testing purposes.
*/
#define TYPE_3 3 /* x**31 + x**3 + 1 */
#define DEG_3 31
#define SEP_3 3
static uint32_t randtbl[DEG_3 + 1] = {
TYPE_3,
0x2cf41758, 0x27bb3711, 0x4916d4d1, 0x7b02f59f, 0x9b8e28eb, 0xc0e80269,
0x696f5c16, 0x878f1ff5, 0x52d9c07f, 0x916a06cd, 0xb50b3a20, 0x2776970a,
0xee4eb2a6, 0xe94640ec, 0xb1d65612, 0x9d1ed968, 0x1043f6b7, 0xa3432a76,
0x17eacbb9, 0x3c09e2eb, 0x4f8c2b3, 0x708a1f57, 0xee341814, 0x95d0e4d2,
0xb06f216c, 0x8bd2e72e, 0x8f7c38d7, 0xcfc6a8fc, 0x2a59495, 0xa20d2a69,
0xe29d12d1
};
static uint32_t *fptr = &randtbl[SEP_3 + 1];
static uint32_t *rptr = &randtbl[1];
static uint32_t * const state = &randtbl[1];
static const int rand_deg = DEG_3;
static const int rand_sep = SEP_3;
static const uint32_t * const end_ptr = &randtbl[DEG_3 + 1];
static inline uint32_t
good_rand(uint32_t ctx)
{
/*
* Compute x = (7^5 * x) mod (2^31 - 1)
* without overflowing 31 bits:
* (2^31 - 1) = 127773 * (7^5) + 2836
* From "Random number generators: good ones are hard to find",
* Park and Miller, Communications of the ACM, vol. 31, no. 10,
* October 1988, p. 1195.
*/
int32_t hi, lo, x;
/* Transform to [1, 0x7ffffffe] range. */
x = (ctx % 0x7ffffffe) + 1;
hi = x / 127773;
lo = x % 127773;
x = 16807 * lo - 2836 * hi;
if (x < 0)
x += 0x7fffffff;
/* Transform to [0, 0x7ffffffd] range. */
return (x - 1);
}
static long
vrnd_RandomTestable(void)
{
uint32_t i;
uint32_t *f, *r;
/*
* Use local variables rather than static variables for speed.
*/
f = fptr; r = rptr;
*f += *r;
i = *f >> 1; /* chucking least random bit */
if (++f >= end_ptr) {
f = state;
++r;
}
else if (++r >= end_ptr) {
r = state;
}
fptr = f; rptr = r;
return ((long)i);
}
void
VRND_SeedTestable(unsigned int x)
{
int i, lim;
state[0] = (uint32_t)x;
for (i = 1; i < rand_deg; i++)
state[i] = good_rand(state[i - 1]);
fptr = &state[rand_sep];
rptr = &state[0];
lim = 10 * rand_deg;
for (i = 0; i < lim; i++)
(void)vrnd_RandomTestable();
}
long
VRND_RandomTestable(void)
{
long l;
AN(VRND_Lock);
VRND_Lock();
l = vrnd_RandomTestable();
AN(VRND_Unlock);
VRND_Unlock();
return (l);
}
double
VRND_RandomTestableDouble(void)
{
return (
ldexp((double)VRND_RandomTestable(), -31) +
ldexp((double)VRND_RandomTestable(), -62)
);
}
int
VRND_RandomCrypto(void *ptr, size_t len)
{
int fd;
char *p = ptr;
ssize_t l;
AN(ptr);
fd = open("/dev/urandom", O_RDONLY);
if (fd < 0)
return (-1);
while (len > 0) {
l = read(fd, p, len);
if (l < 0)
break;
p += l;
len -= l;
}
closefd(&fd);
return (len == 0 ? 0 : -1);
}
void
VRND_SeedAll(void)
{
unsigned long seed;
AZ(VRND_RandomCrypto(&seed, sizeof seed));
srandom(seed);
AZ(VRND_RandomCrypto(&seed, sizeof seed));
VRND_SeedTestable(seed);
AZ(VRND_RandomCrypto(&seed, sizeof seed));
srand48((long)seed);
}
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