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/*
* Embedded Linux library
* Copyright (C) 2015 Intel Corporation
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#define _GNU_SOURCE
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/syscall.h>
#include "random.h"
#include "private.h"
#include "missing.h"
#ifndef GRND_NONBLOCK
#define GRND_NONBLOCK 0x0001
#endif
#ifndef GRND_RANDOM
#define GRND_RANDOM 0x0002
#endif
static inline int getrandom(void *buffer, size_t count, unsigned flags) {
return syscall(__NR_getrandom, buffer, count, flags);
}
/**
* l_getrandom:
* @buf: buffer to fill with random data
* @len: length of random data requested
*
* Request a number of randomly generated bytes given by @len and put them
* into buffer @buf.
*
* Returns: true if the random data could be generated, false otherwise.
**/
LIB_EXPORT bool l_getrandom(void *buf, size_t len)
{
while (len) {
int ret;
ret = L_TFR(getrandom(buf, len, 0));
if (ret < 0)
return false;
buf += ret;
len -= ret;
}
return true;
}
LIB_EXPORT bool l_getrandom_is_supported()
{
static bool initialized = false;
static bool supported = true;
uint8_t buf[4];
int ret;
if (initialized)
return supported;
ret = getrandom(buf, sizeof(buf), GRND_NONBLOCK);
if (ret < 0 && errno == ENOSYS)
supported = false;
initialized = true;
return supported;
}
LIB_EXPORT uint32_t l_getrandom_uint32(void)
{
int ret;
uint32_t u;
ret = getrandom(&u, sizeof(u), GRND_NONBLOCK);
if (ret == sizeof(u))
return u;
return random() * RAND_MAX + random();
}
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