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/*
* BIRD Internet Routing Daemon -- Random Numbers
*
* (c) 2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include "sysdep/config.h"
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif
#ifdef HAVE_LINUX_RANDOM_H
# include <linux/random.h>
#endif
#if defined(HAVE_SYS_RANDOM_H) && (defined(HAVE_GETRANDOM) || defined(HAVE_GETENTROPY))
# include <sys/random.h>
#endif
#include "nest/bird.h"
u32
random_u32(void)
{
long int rand_low, rand_high;
rand_low = random();
rand_high = random();
return (rand_low & 0xffff) | ((rand_high & 0xffff) << 16);
}
void
random_init()
{
char buf;
/* get a single random byte to trip any errors early */
random_bytes(&buf, sizeof(buf));
}
#if defined(HAVE_GETRANDOM) || defined(HAVE_GENTROPY)
int
random_bytes(char *buf, size_t size)
{
int n;
int flags = 0;
while (0 < size) {
#if defined(HAVE_GETRANDOM)
n = getrandom(buf, size, flags);
#else
n = getentropy(buf, size);
#endif
if (n < 0) {
if (errno == EINTR)
continue;
die("Couldn't get random bytes: %m");
}
buf += n;
size -= n;
}
return 0;
}
void random_close(void) {}
#else
static int urandom_fd = -1;
int random_bytes(char *buf, size_t size)
{
int n;
if (urandom_fd < 0)
{
urandom_fd = open("/dev/urandom", O_RDONLY);
if (urandom_fd < 0)
die("Couldn't open /dev/urandom: %m");
}
do
{
n = read(urandom_fd, buf, size);
if (n <= 0) {
if (errno == EINTR)
continue;
die("Couldn't read from /dev/urandom: %m");
}
buf += n;
size -= n;
} while (size > 0);
return 0;
}
void
random_close(void)
{
if (urandom_fd >= 0) {
close(urandom_fd);
urandom_fd = -1;
}
}
#endif
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