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/*
* Random numbers
* Copyright Jan Engelhardt, 2003-2008
*
* This file is part of libHX. libHX is free software; you can
* redistribute it and/or modify it under the terms of the GNU Lesser
* General Public License as published by the Free Software Foundation;
* either version 2.1 or (at your option) any later version.
*/
#include "config.h"
#include <sys/stat.h>
#include <fcntl.h>
#include <pthread.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#ifdef __unix__
# include <unistd.h>
#endif
#ifdef _WIN32
# include <process.h>
#endif
#include <libHX/init.h>
#include <libHX/misc.h>
#include "internal.h"
static unsigned int HXrand_obtain_seed(void)
{
unsigned int s;
#if defined(HAVE_CLOCK_GETTIME)
struct timespec tv;
clock_gettime(CLOCK_REALTIME, &tv);
s = tv.tv_sec;
s ^= ~tv.tv_nsec;
clock_gettime(CLOCK_MONOTONIC, &tv);
s ^= tv.tv_sec;
s ^= ~tv.tv_nsec;
#else
s = time(NULL);
#endif
#ifdef HAVE_GETPID
s ^= getpid() << 9;
#endif
#ifdef HAVE_GETPPID
s ^= getppid() << 1;
#endif
#ifdef HAVE_GETEUID
s ^= geteuid() << 13;
#endif
#ifdef HAVE_GETEGID
s ^= getegid() << 5;
#endif
return s;
}
static void HXrand_init(void)
{
unsigned int seed;
int fd, ret = 0;
if ((fd = open("/dev/urandom", O_RDONLY | O_BINARY)) >= 0) {
ret = read(fd, &seed, sizeof(seed));
close(fd);
}
if (ret != sizeof(seed))
seed = HXrand_obtain_seed();
srand(seed);
}
static pthread_mutex_t HX_init_lock = PTHREAD_MUTEX_INITIALIZER;
static unsigned long HX_use_count;
EXPORT_SYMBOL int HX_init(void)
{
pthread_mutex_lock(&HX_init_lock);
if (HX_use_count == 0)
HXrand_init();
++HX_use_count;
pthread_mutex_unlock(&HX_init_lock);
return 1;
}
EXPORT_SYMBOL void HX_exit(void)
{
pthread_mutex_lock(&HX_init_lock);
if (HX_use_count == 0)
fprintf(stderr, "%s: reference count is already zero!\n", __func__);
else
--HX_use_count;
pthread_mutex_unlock(&HX_init_lock);
}
EXPORT_SYMBOL int HX_rand(void)
{
/*
* If there is an overly broken system, we may need to use
* alternate methods again (/dev/urandom?)
*/
return rand();
}
EXPORT_SYMBOL double HX_drand(double lo, double hi)
{
double delta = hi - lo;
return static_cast(double, rand()) * delta / RAND_MAX + lo;
}
EXPORT_SYMBOL unsigned int HX_irand(unsigned int lo, unsigned int hi)
{
unsigned int delta = hi - lo;
if (delta == 0)
return lo;
else if (delta <= RAND_MAX)
return rand() % delta + lo;
else
return static_cast(unsigned int,
static_cast(double, rand()) * delta / RAND_MAX) + lo;
}
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