| | varnish-cache/lib/libvarnish/vrnd.c |
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/*- |
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* Copyright (c) 2006 Verdens Gang AS |
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* Copyright (c) 2006-2011 Varnish Software AS |
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* Copyright (c) 1983, 1993 The Regents of the University of California. |
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* All rights reserved. |
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* |
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* Author: Dag-Erling Smørgrav <des@des.no> |
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* |
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* SPDX-License-Identifier: BSD-2-Clause |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* |
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* Partially from: $FreeBSD: head/lib/libc/stdlib/random.c 303342 |
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* |
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*/ |
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#include "config.h" |
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#include <fcntl.h> |
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#include <math.h> |
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#include <stdint.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <unistd.h> |
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#include "vdef.h" |
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#include "vas.h" |
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#include "vrnd.h" |
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vrnd_lock_f *VRND_Lock; |
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vrnd_lock_f *VRND_Unlock; |
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/********************************************************************** |
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* Stripped down random(3) implementation from FreeBSD, to provide |
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* predictable "random" numbers of testing purposes. |
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*/ |
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#define TYPE_3 3 /* x**31 + x**3 + 1 */ |
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#define DEG_3 31 |
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#define SEP_3 3 |
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static uint32_t randtbl[DEG_3 + 1] = { |
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TYPE_3, |
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0x2cf41758, 0x27bb3711, 0x4916d4d1, 0x7b02f59f, 0x9b8e28eb, 0xc0e80269, |
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0x696f5c16, 0x878f1ff5, 0x52d9c07f, 0x916a06cd, 0xb50b3a20, 0x2776970a, |
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0xee4eb2a6, 0xe94640ec, 0xb1d65612, 0x9d1ed968, 0x1043f6b7, 0xa3432a76, |
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0x17eacbb9, 0x3c09e2eb, 0x4f8c2b3, 0x708a1f57, 0xee341814, 0x95d0e4d2, |
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0xb06f216c, 0x8bd2e72e, 0x8f7c38d7, 0xcfc6a8fc, 0x2a59495, 0xa20d2a69, |
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0xe29d12d1 |
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}; |
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static uint32_t *fptr = &randtbl[SEP_3 + 1]; |
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static uint32_t *rptr = &randtbl[1]; |
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static uint32_t * const state = &randtbl[1]; |
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static const int rand_deg = DEG_3; |
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static const int rand_sep = SEP_3; |
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static const uint32_t * const end_ptr = &randtbl[DEG_3 + 1]; |
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static inline uint32_t |
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5889330 |
good_rand(uint32_t ctx) |
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{ |
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/* |
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* Compute x = (7^5 * x) mod (2^31 - 1) |
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* without overflowing 31 bits: |
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* (2^31 - 1) = 127773 * (7^5) + 2836 |
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* From "Random number generators: good ones are hard to find", |
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* Park and Miller, Communications of the ACM, vol. 31, no. 10, |
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* October 1988, p. 1195. |
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*/ |
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int32_t hi, lo, x; |
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/* Transform to [1, 0x7ffffffe] range. */ |
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5889330 |
x = (ctx % 0x7ffffffe) + 1; |
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5889330 |
hi = x / 127773; |
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lo = x % 127773; |
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x = 16807 * lo - 2836 * hi; |
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if (x < 0) |
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x += 0x7fffffff; |
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/* Transform to [0, 0x7ffffffd] range. */ |
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return (x - 1); |
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} |
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static long |
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193671154 |
vrnd_RandomTestable(void) |
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{ |
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uint32_t i; |
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uint32_t *f, *r; |
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/* |
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* Use local variables rather than static variables for speed. |
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*/ |
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193671154 |
f = fptr; r = rptr; |
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193671154 |
*f += *r; |
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i = *f >> 1; /* chucking least random bit */ |
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193671154 |
if (++f >= end_ptr) { |
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6247255 |
f = state; |
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6247255 |
++r; |
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} |
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else if (++r >= end_ptr) { |
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r = state; |
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} |
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fptr = f; rptr = r; |
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return ((long)i); |
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} |
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void |
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196311 |
VRND_SeedTestable(unsigned int x) |
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{ |
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int i, lim; |
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state[0] = (uint32_t)x; |
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for (i = 1; i < rand_deg; i++) |
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state[i] = good_rand(state[i - 1]); |
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fptr = &state[rand_sep]; |
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rptr = &state[0]; |
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lim = 10 * rand_deg; |
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for (i = 0; i < lim; i++) |
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(void)vrnd_RandomTestable(); |
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} |
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long |
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VRND_RandomTestable(void) |
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{ |
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long l; |
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AN(VRND_Lock); |
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VRND_Lock(); |
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l = vrnd_RandomTestable(); |
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AN(VRND_Unlock); |
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VRND_Unlock(); |
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return (l); |
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} |
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double |
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VRND_RandomTestableDouble(void) |
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{ |
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return ( |
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ldexp((double)VRND_RandomTestable(), -31) + |
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ldexp((double)VRND_RandomTestable(), -62) |
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); |
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} |
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int |
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13255281 |
VRND_RandomCrypto(void *ptr, size_t len) |
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{ |
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int fd; |
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13255281 |
char *p = ptr; |
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ssize_t l; |
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13255281 |
AN(ptr); |
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13255281 |
fd = open("/dev/urandom", O_RDONLY); |
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13255281 |
if (fd < 0) |
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return (-1); |
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while (len > 0) { |
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13255281 |
l = read(fd, p, len); |
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13255281 |
if (l < 0) |
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break; |
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13255281 |
p += l; |
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13255281 |
len -= l; |
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} |
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closefd(&fd); |
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return (len == 0 ? 0 : -1); |
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} |
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void |
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VRND_SeedAll(void) |
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{ |
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unsigned long seed; |
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AZ(VRND_RandomCrypto(&seed, sizeof seed)); |
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srandom(seed); |
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AZ(VRND_RandomCrypto(&seed, sizeof seed)); |
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VRND_SeedTestable(seed); |
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AZ(VRND_RandomCrypto(&seed, sizeof seed)); |
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srand48((long)seed); |
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} |