This is xnu-8019. See this file in:
/*
 * Copyright (c) 2000-2002 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@
 */
/*	@(#)loadable_fs.h	2.0	26/06/90	(c) 1990 NeXT	*/

/* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
 *
 * W I L L    D R A S T I C A L L Y   C H A N G E   S O O N
 * U S E   A T  Y O U R   O W N  R I S K
 *
 * XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */


/*
 * loadable_fs.h - message struct for loading and initializing loadable
 *		   file systems.
 */

#ifndef _SYS_LOADABLE_FS_
#define _SYS_LOADABLE_FS_


/*
 * Constants for Loadable FS Utilities (in "/System/Library/Filesystems")
 *
 * Example of a /usr/filesystems directory
 *
 * /usr/filesystems/dos.fs/dos.util		utility with which WSM
 *							communicates
 * /usr/filesystems/dos.fs/dos.name             "DOS Floppy"
 * /usr/filesystems/dos.fs/dos_reloc		actual loadable filesystem
 * /usr/filesystems/dos.fs/dos.openfs.tiff	"open folder" icon
 * /usr/filesystems/dos.fs/dos.fs.tiff		"closed folder" icon
 */
#define FS_DIR_LOCATION         "/System/Library/Filesystems"
#define FS_DIR_SUFFIX           ".fs"
#define FS_UTIL_SUFFIX          ".util"

/*
 * .util program commands - all sent in the form "-p" or "-m" ... as argv[1].
 */
#define FSUC_PROBE              'p'     /* probe FS for mount or init */
/* example usage: foo.util -p fd0 removable writable */

#define FSUC_PROBEFORINIT       'P'     /* probe FS for init only */
/* example usage: foo.util -P fd0 removable */

#define FSUC_MOUNT              'm'     /* mount FS */
/* example usage: foo.util -m fd0 /bar removable writable */

#define FSUC_REPAIR             'r'     /* repair ('fsck') FS */
/* example usage: foo.util -r fd0 removable */

#define FSUC_UNMOUNT            'u'     /* unmount FS */
/* example usage: foo.util -u fd0 /bar */

/* The following is not used by Workspace Manager */
#define FSUC_MOUNT_FORCE        'M'     /* like FSUC_MOUNT, but proceed even on
	                                 * error. */
/*
 * Return codes from .util program
 */
#define FSUR_RECOGNIZED         (-1)    /* response to FSUC_PROBE; implies that
	                                 * a mount is possible */
#define FSUR_UNRECOGNIZED       (-2)    /* negative response to FSUC_PROBE */
#define FSUR_IO_SUCCESS         (-3)    /* mount, unmount, repair succeeded */
#define FSUR_IO_FAIL            (-4)    /* unrecoverable I/O error */
#define FSUR_IO_UNCLEAN         (-5)    /* mount failed, file system not clean
	                                 */
#define FSUR_INVAL              (-6)    /* invalid argument */
#define FSUR_LOADERR            (-7)    /* kern_loader error */
#define FSUR_INITRECOGNIZED     (-8)    /* response to FSUC_PROBE or
	                                 * FSUC_PROBEFORINIT, implies that
	                                 * initialization is possible */

/*
 *	mount parameters passed from WSM to the .util program.
 */
#define DEVICE_READONLY         "readonly"
#define DEVICE_WRITABLE         "writable"

#define DEVICE_REMOVABLE        "removable"
#define DEVICE_FIXED            "fixed"

#endif  /* _SYS_LOADABLE_FS_ */