FreeBSD/Linux Kernel Cross Reference
sys/fs/msdosfs/fat.h

     /*      $NetBSD: fat.h,v 1.4 2005/12/03 17:34:43 christos Exp $ */
     
     /*-
      * Copyright (C) 1994, 1997 Wolfgang Solfrank.
      * Copyright (C) 1994, 1997 TooLs GmbH.
      * All rights reserved.
      * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
      *
      * 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 TooLs GmbH.
     * 4. The name of TooLs GmbH may not be used to endorse or promote products
     *    derived from this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``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 TOOLS GMBH 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.
     */
    /*
     * Written by Paul Popelka (paulp@uts.amdahl.com)
     *
     * You can do anything you want with this software, just don't say you wrote
     * it, and don't remove this notice.
     *
     * This software is provided "as is".
     *
     * The author supplies this software to be publicly redistributed on the
     * understanding that the author is not responsible for the correct
     * functioning of this software in any circumstances and is not liable for
     * any damages caused by this software.
     *
     * October 1992
     */
    
    #ifndef _MSDOSFS_FAT_H_
    #define _MSDOSFS_FAT_H_
    /*
     * Some useful cluster numbers.
     */
    #define MSDOSFSROOT     0               /* cluster 0 means the root dir */
    #define CLUST_FREE      0               /* cluster 0 also means a free cluster */
    #define MSDOSFSFREE     CLUST_FREE
    #define CLUST_FIRST     2               /* first legal cluster number */
    #define CLUST_RSRVD     0xfffffff6      /* reserved cluster range */
    #define CLUST_BAD       0xfffffff7      /* a cluster with a defect */
    #define CLUST_EOFS      0xfffffff8      /* start of eof cluster range */
    #define CLUST_EOFE      0xffffffff      /* end of eof cluster range */
    #define CLUST_END       CLUST_EOFE      /* bigger than any valid cluster */
    
    #define FAT12_MASK      0x00000fff      /* mask for 12 bit cluster numbers */
    #define FAT16_MASK      0x0000ffff      /* mask for 16 bit cluster numbers */
    #define FAT32_MASK      0x0fffffff      /* mask for FAT32 cluster numbers */
    
    /*
     * MSDOSFS:
     * Return true if filesystem uses 12 bit fats. Microsoft Programmer's
     * Reference says if the maximum cluster number in a filesystem is greater
     * than 4078 ((CLUST_RSRVS - CLUST_FIRST) & FAT12_MASK) then we've got a
     * 16 bit fat filesystem. While mounting, the result of this test is stored
     * in pm_fatentrysize.
     * GEMDOS-flavour (atari):
     * If the filesystem is on floppy we've got a 12 bit fat filesystem, otherwise
     * 16 bit. We check the d_type field in the disklabel struct while mounting
     * and store the result in the pm_fatentrysize. Note that this kind of
     * detection gets flakey when mounting a vnd-device.
     */
    #define FAT12(pmp)      (pmp->pm_fatmask == FAT12_MASK)
    #define FAT16(pmp)      (pmp->pm_fatmask == FAT16_MASK)
    #define FAT32(pmp)      (pmp->pm_fatmask == FAT32_MASK)
    
    /*
     * M$ in it's unlimited wisdom desided that EOF mark is anything
     * between 0xfffffff8 and 0xffffffff (masked by appropriate fatmask,
     * of course).
     * Note that cn is supposed to be already adjusted accordingly to FAT type.
     */
    #define MSDOSFSEOF(cn, fatmask) \
            (((cn) & CLUST_EOFS) == (CLUST_EOFS & (fatmask)))
    
    #ifdef _KERNEL
    /*
     * These are the values for the function argument to the function
     * fatentry().
     */
   #define FAT_GET         0x0001  /* get a fat entry */
   #define FAT_SET         0x0002  /* set a fat entry */
   #define FAT_GET_AND_SET (FAT_GET | FAT_SET)
   
   /*
    * Flags to extendfile:
    */
   #define DE_CLEAR        1       /* Zero out the blocks allocated */
   
   int pcbmap(struct denode *, u_long, daddr_t *, u_long *, int *);
   int clusterfree(struct msdosfsmount *, u_long, u_long *);
   int clusteralloc(struct msdosfsmount *, u_long, u_long,u_long *,u_long *);
   int extendfile(struct denode *, u_long, struct buf **, u_long *, int);
   int fatentry(int, struct msdosfsmount *, u_long, u_long *, u_long);
   void fc_purge(struct denode *, u_int);
   void fc_lookup(struct denode *, u_long, u_long *, u_long *);
   int fillinusemap(struct msdosfsmount *);
   int freeclusterchain(struct msdosfsmount *, u_long);
   #endif  /* _KERNEL */
   #endif /* _MSDOSFS_FAT_H_ */

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