This is xnu-8019. See this file in:
/*
 * Copyright (c) 2003-2012 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@
 */

/*
 * [XSI] The symbolic names for file modes for use as values of mode_t
 * shall be defined as described in <sys/stat.h>
 */
#ifndef S_IFMT
/* File type */
#define S_IFMT          0170000         /* [XSI] type of file mask */
#define S_IFIFO         0010000         /* [XSI] named pipe (fifo) */
#define S_IFCHR         0020000         /* [XSI] character special */
#define S_IFDIR         0040000         /* [XSI] directory */
#define S_IFBLK         0060000         /* [XSI] block special */
#define S_IFREG         0100000         /* [XSI] regular */
#define S_IFLNK         0120000         /* [XSI] symbolic link */
#define S_IFSOCK        0140000         /* [XSI] socket */
#if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
#define S_IFWHT         0160000         /* OBSOLETE: whiteout */
#endif

/* File mode */
/* Read, write, execute/search by owner */
#define S_IRWXU         0000700         /* [XSI] RWX mask for owner */
#define S_IRUSR         0000400         /* [XSI] R for owner */
#define S_IWUSR         0000200         /* [XSI] W for owner */
#define S_IXUSR         0000100         /* [XSI] X for owner */
/* Read, write, execute/search by group */
#define S_IRWXG         0000070         /* [XSI] RWX mask for group */
#define S_IRGRP         0000040         /* [XSI] R for group */
#define S_IWGRP         0000020         /* [XSI] W for group */
#define S_IXGRP         0000010         /* [XSI] X for group */
/* Read, write, execute/search by others */
#define S_IRWXO         0000007         /* [XSI] RWX mask for other */
#define S_IROTH         0000004         /* [XSI] R for other */
#define S_IWOTH         0000002         /* [XSI] W for other */
#define S_IXOTH         0000001         /* [XSI] X for other */

#define S_ISUID         0004000         /* [XSI] set user id on execution */
#define S_ISGID         0002000         /* [XSI] set group id on execution */
#define S_ISVTX         0001000         /* [XSI] directory restrcted delete */

#if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
#define S_ISTXT         S_ISVTX         /* sticky bit: not supported */
#define S_IREAD         S_IRUSR         /* backward compatability */
#define S_IWRITE        S_IWUSR         /* backward compatability */
#define S_IEXEC         S_IXUSR         /* backward compatability */
#endif
#endif  /* !S_IFMT */