This is xnu-8019. See this file in:
/*
 * Copyright (c) 2000 Apple Computer, 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@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*-
 * Copyright (c) 1982, 1986, 1990, 1993, 1994
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)ioccom.h	8.2 (Berkeley) 3/28/94
 */

#ifndef _SYS_IOCCOM_H_
#define _SYS_IOCCOM_H_

#include <sys/_types.h>

/*
 * Ioctl's have the command encoded in the lower word, and the size of
 * any in or out parameters in the upper word.  The high 3 bits of the
 * upper word are used to encode the in/out status of the parameter.
 */
#define IOCPARM_MASK    0x1fff          /* parameter length, at most 13 bits */
#define IOCPARM_LEN(x)  (((x) >> 16) & IOCPARM_MASK)
#define IOCBASECMD(x)   ((x) & ~(IOCPARM_MASK << 16))
#define IOCGROUP(x)     (((x) >> 8) & 0xff)

#define IOCPARM_MAX     (IOCPARM_MASK + 1)      /* max size of ioctl args */
/* no parameters */
#define IOC_VOID        (__uint32_t)0x20000000
/* copy parameters out */
#define IOC_OUT         (__uint32_t)0x40000000
/* copy parameters in */
#define IOC_IN          (__uint32_t)0x80000000
/* copy parameters in and out */
#define IOC_INOUT       (IOC_IN|IOC_OUT)
/* mask for IN/OUT/VOID */
#define IOC_DIRMASK     (__uint32_t)0xe0000000

#define _IOC(inout, group, num, len) \
	(inout | ((len & IOCPARM_MASK) << 16) | ((group) << 8) | (num))
#define _IO(g, n)        _IOC(IOC_VOID,	(g), (n), 0)
#define _IOR(g, n, t)     _IOC(IOC_OUT,	(g), (n), sizeof(t))
#define _IOW(g, n, t)     _IOC(IOC_IN,	(g), (n), sizeof(t))
/* this should be _IORW, but stdio got there first */
#define _IOWR(g, n, t)    _IOC(IOC_INOUT,	(g), (n), sizeof(t))

#endif /* !_SYS_IOCCOM_H_ */