This is xnu-8019. See this file in:
/*
 * Copyright (c) 1999, 2000-2002, 2009 Apple, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

/*
 *       WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!
 *
 *       THIS FILE IS NEEDED TO PASS FIPS ACCEPTANCE FOR THE RANDOM NUMBER GENERATOR.
 *       IF YOU ALTER IT IN ANY WAY, WE WILL NEED TO GO THOUGH FIPS ACCEPTANCE AGAIN,
 *       AN OPERATION THAT IS VERY EXPENSIVE AND TIME CONSUMING.  IN OTHER WORDS,
 *       DON'T MESS WITH THIS FILE.
 *
 *       WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!
 */

#ifndef __DEV_RANDOMDEV_H__
#define __DEV_RANDOMDEV_H__

#include <sys/appleapiopts.h>

#ifdef __APPLE_API_PRIVATE

#include <sys/random.h>

void PreliminarySetup( void );
void random_init( void );
int random_open(dev_t dev, int flags, int devtype, struct proc *pp);
int random_close(dev_t dev, int flags, int mode, struct proc *pp);
int random_read(dev_t dev, struct uio *uio, int ioflag);
int random_write(dev_t dev, struct uio *uio, int ioflag);

u_int32_t RandomULong( void );

#endif /* __APPLE_API_PRIVATE */
#endif /* __DEV_RANDOMDEV_H__ */