usr/src/lib/libc/port/gen/getentropy.c

/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright (c) 2015, Joyent, Inc.
 */

/*
 * getentropy(3C) is an OpenBSD compatible wrapper around getrandom(2).
 */

#include <errno.h>
#include <sys/random.h>

int
getentropy(void *buf, size_t buflen)
{
	int ret;

	if (buflen > 256) {
		errno = EIO;
		return (-1);
	}

	ret = getrandom(buf, buflen, 0);
	if (ret == -1 || ret != buflen) {
		if (errno != EFAULT)
			errno = EIO;
		return (-1);
	}

	return (0);
}