This is xnu-8019. See this file in:
/*
 * Copyright (c) 2000-2004 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, 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.
 *
 *	@(#)uio.h	8.5 (Berkeley) 2/22/94
 */

#ifndef _SYS_UIO_INTERNAL_H_
#define _SYS_UIO_INTERNAL_H_

#include <sys/appleapiopts.h>

#ifdef KERNEL_PRIVATE
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/param.h>

/*
 * user / kernel address space type flags.
 * WARNING - make sure to check when adding flags!  Be sure new flags
 * don't overlap the definitions in uio.h
 */
//      UIO_USERSPACE           0       defined in uio.h
#define UIO_USERISPACE          ((enum uio_seg)1)
//      UIO_SYSSPACE            2       defined in uio.h
#define UIO_PHYS_USERSPACE      ((enum uio_seg)3)
#define UIO_PHYS_SYSSPACE       ((enum uio_seg)4)
//      UIO_USERSPACE32         5       defined in uio.h
#define UIO_USERISPACE32        ((enum uio_seg)6)
#define UIO_PHYS_USERSPACE32    ((enum uio_seg)7)
//      UIO_USERSPACE64         8       defined in uio.h
#define UIO_USERISPACE64        ((enum uio_seg)9)
#define UIO_PHYS_USERSPACE64    ((enum uio_seg)10)
//      UIO_SYSSPACE32          11      defined in uio.h
//      UIO_PHYS_SYSSPACE32     12      reserved, never used. Use UIO_PHYS_SYSSPACE
//      UIO_SYSSPACE64          13      reserved, never used. Use UIO_SYSSPACE
//      UIO_PHYS_SYSSPACE64     14      reserved, never used. Use UIO_PHYS_SYSSPACE

__BEGIN_DECLS
struct user_iovec;

#ifdef XNU_KERNEL_PRIVATE
__private_extern__ struct user_iovec * uio_iovsaddr( uio_t a_uio );
__private_extern__ int uio_calculateresid( uio_t a_uio );
__private_extern__ void uio_setcurriovlen( uio_t a_uio, user_size_t a_value );
__private_extern__ int uio_spacetype( uio_t a_uio );
__private_extern__ uio_t  uio_createwithbuffer( int a_iovcount, off_t a_offset, int a_spacetype, int a_iodirection, void *a_buf_p, size_t a_buffer_size );
__private_extern__ int copyin_user_iovec_array(user_addr_t uaddr, int spacetype, int count, struct user_iovec *dst);
/* reverse of uio_update to "undo" uncommited I/O. This only works in
 * limited cases */
__private_extern__ void uio_pushback( uio_t a_uio, user_size_t a_count );
#endif /* XNU_KERNEL_PRIVATE */

/* use kern_iovec for system space requests */
struct kern_iovec {
	u_int64_t       iov_base;       /* Base address; PAC signed, diversified with length. */
	u_int64_t       iov_len;        /* Length. */
};

/* use user_iovec for user space requests */
struct user_iovec {
	user_addr_t     iov_base;       /* Base address. */
	user_size_t     iov_len;        /* Length. */
};

/* use user32_iovec/user64_iovec for representing
 * in-memory structures in 32-64 processes during copyin */
struct user32_iovec {
	uint32_t        iov_base;       /* Base address. */
	uint32_t        iov_len;        /* Length. */
};

struct user64_iovec {
	uint64_t        iov_base;       /* Base address. */
	uint64_t        iov_len;        /* Length. */
};

union iovecs {
	struct kern_iovec       *kiovp;
	struct user_iovec       *uiovp;
};

/* WARNING - use accessor calls for uio_iov and uio_resid since these */
/* fields vary depending on the originating address space. */
struct uio {
	void * XNU_PTRAUTH_SIGNED_PTR("uio.uio_iovs") uio_iovs;       /* current iovec */
	void * XNU_PTRAUTH_SIGNED_PTR("uio.uio_iovbase") uio_iovbase; /* iovec base */
	int             uio_max_iovs;   /* max number of iovecs this uio_t can hold */
	int             uio_iovcnt;     /* active iovecs */
	off_t           uio_offset;
	enum uio_seg    uio_segflg;
	enum uio_rw     uio_rw;
	user_size_t     uio_resid_64;
	u_int32_t       uio_flags;
};

/* values for uio_flags */
#define UIO_FLAGS_INITED                0x00000001
#define UIO_FLAGS_WE_ALLOCED    0x00000002
#define UIO_FLAGS_IS_COMPRESSED_FILE    0x00000004

__END_DECLS

#define UIO_SIZEOF_IOVS( a_iovcount ) \
	( MAX(sizeof(struct user_iovec), sizeof(struct kern_iovec)) * (a_iovcount) )

/*
 * UIO_SIZEOF - return the amount of space a uio_t requires to
 *	contain the given number of iovecs.  Use this macro to
 *  create a stack buffer (of type uio_stackbuf_t to ensure
 *  alignment requirements) that can be passed to
 *  uio_createwithbuffer.
 */
#define UIO_SIZEOF( a_iovcount ) \
	( sizeof(struct uio) + UIO_SIZEOF_IOVS(a_iovcount) )

typedef char __attribute__((aligned(_Alignof(union iovecs)))) uio_stackbuf_t;

#define UIO_IS_USER_SPACE32( a_uio_t )  \
	( (a_uio_t)->uio_segflg == UIO_USERSPACE32 || (a_uio_t)->uio_segflg == UIO_PHYS_USERSPACE32 || \
	  (a_uio_t)->uio_segflg == UIO_USERISPACE32 )
#define UIO_IS_USER_SPACE64( a_uio_t )  \
	( (a_uio_t)->uio_segflg == UIO_USERSPACE64 || (a_uio_t)->uio_segflg == UIO_PHYS_USERSPACE64 || \
	  (a_uio_t)->uio_segflg == UIO_USERISPACE64 )
#define UIO_IS_USER_SPACE( a_uio_t )  \
	( UIO_IS_USER_SPACE32((a_uio_t)) || UIO_IS_USER_SPACE64((a_uio_t)) || \
	  (a_uio_t)->uio_segflg == UIO_USERSPACE || (a_uio_t)->uio_segflg == UIO_USERISPACE || \
	   (a_uio_t)->uio_segflg == UIO_PHYS_USERSPACE )
#define UIO_IS_SYS_SPACE( a_uio_t )  \
	( (a_uio_t)->uio_segflg == UIO_SYSSPACE || (a_uio_t)->uio_segflg == UIO_PHYS_SYSSPACE || \
	  (a_uio_t)->uio_segflg == UIO_SYSSPACE32 )

extern int ureadc(int c, struct uio *uio);

#endif /* KERNEL_PRIVATE */
#endif /* !_SYS_UIO_INTERNAL_H_ */