sys/fs/msdosfs/fat.h

   1 /*      $NetBSD: fat.h,v 1.3 2005/08/29 23:57:35 xtraeme Exp $  */
   2
   3 /*-
   4  * Copyright (C) 1994, 1997 Wolfgang Solfrank.
   5  * Copyright (C) 1994, 1997 TooLs GmbH.
   6  * All rights reserved.
   7  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by TooLs GmbH.
  20  * 4. The name of TooLs GmbH may not be used to endorse or promote products
  21  *    derived from this software without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
  24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  26  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  27  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  28  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  29  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  30  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  31  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  32  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33  */
  34 /*
  35  * Written by Paul Popelka (paulp@uts.amdahl.com)
  36  *
  37  * You can do anything you want with this software, just don't say you wrote
  38  * it, and don't remove this notice.
  39  *
  40  * This software is provided "as is".
  41  *
  42  * The author supplies this software to be publicly redistributed on the
  43  * understanding that the author is not responsible for the correct
  44  * functioning of this software in any circumstances and is not liable for
  45  * any damages caused by this software.
  46  *
  47  * October 1992
  48  */
  49
  50 #ifndef _MSDOSFS_FAT_H_
  51 #define _MSDOSFS_FAT_H_
  52 /*
  53  * Some useful cluster numbers.
  54  */
  55 #define MSDOSFSROOT     0               /* cluster 0 means the root dir */
  56 #define CLUST_FREE      0               /* cluster 0 also means a free cluster */
  57 #define MSDOSFSFREE     CLUST_FREE
  58 #define CLUST_FIRST     2               /* first legal cluster number */
  59 #define CLUST_RSRVD     0xfffffff6      /* reserved cluster range */
  60 #define CLUST_BAD       0xfffffff7      /* a cluster with a defect */
  61 #define CLUST_EOFS      0xfffffff8      /* start of eof cluster range */
  62 #define CLUST_EOFE      0xffffffff      /* end of eof cluster range */
  63 #define CLUST_END       CLUST_EOFE      /* bigger than any valid cluster */
  64
  65 #define FAT12_MASK      0x00000fff      /* mask for 12 bit cluster numbers */
  66 #define FAT16_MASK      0x0000ffff      /* mask for 16 bit cluster numbers */
  67 #define FAT32_MASK      0x0fffffff      /* mask for FAT32 cluster numbers */
  68
  69 /*
  70  * MSDOSFS:
  71  * Return true if filesystem uses 12 bit fats. Microsoft Programmer's
  72  * Reference says if the maximum cluster number in a filesystem is greater
  73  * than 4078 ((CLUST_RSRVS - CLUST_FIRST) & FAT12_MASK) then we've got a
  74  * 16 bit fat filesystem. While mounting, the result of this test is stored
  75  * in pm_fatentrysize.
  76  * GEMDOS-flavour (atari):
  77  * If the filesystem is on floppy we've got a 12 bit fat filesystem, otherwise
  78  * 16 bit. We check the d_type field in the disklabel struct while mounting
  79  * and store the result in the pm_fatentrysize. Note that this kind of
  80  * detection gets flakey when mounting a vnd-device.
  81  */
  82 #define FAT12(pmp)      (pmp->pm_fatmask == FAT12_MASK)
  83 #define FAT16(pmp)      (pmp->pm_fatmask == FAT16_MASK)
  84 #define FAT32(pmp)      (pmp->pm_fatmask == FAT32_MASK)
  85
  86 /*
  87  * M$ in it's unlimited wisdom desided that EOF mark is anything
  88  * between 0xfffffff8 and 0xffffffff (masked by appropriate fatmask,
  89  * of course).
  90  * Note that cn is supposed to be already adjusted accordingly to FAT type.
  91  */
  92 #define MSDOSFSEOF(cn, fatmask) \
  93         (((cn) & CLUST_EOFS) == (CLUST_EOFS & (fatmask)))
  94
  95 #ifdef _KERNEL
  96 /*
  97  * These are the values for the function argument to the function
  98  * fatentry().
  99  */
 100 #define FAT_GET         0x0001  /* get a fat entry */
 101 #define FAT_SET         0x0002  /* set a fat entry */
 102 #define FAT_GET_AND_SET (FAT_GET | FAT_SET)
 103
 104 /*
 105  * Flags to extendfile:
 106  */
 107 #define DE_CLEAR        1       /* Zero out the blocks allocated */
 108
 109 int pcbmap(struct denode *, u_long, daddr_t *, u_long *, int *);
 110 int clusterfree(struct msdosfsmount *, u_long, u_long *);
 111 int clusteralloc(struct msdosfsmount *, u_long, u_long,u_long *,u_long *);
 112 int extendfile(struct denode *, u_long, struct buf **, u_long *, int);
 113 int fatentry(int, struct msdosfsmount *, u_long, u_long *, u_long);
 114 void fc_purge(struct denode *, u_int);
 115 void fc_lookup(struct denode *, u_long, u_long *, u_long *);
 116 int fillinusemap(struct msdosfsmount *);
 117 int freeclusterchain(struct msdosfsmount *, u_long);
 118 #endif  /* _KERNEL */
 119 #endif /* _MSDOSFS_FAT_H_ */