xref: /openbsd/usr.sbin/makefs/msdos/fat.h (revision 72290da1)
1 /*	$OpenBSD: fat.h,v 1.1 2016/10/18 17:05:30 natano Exp $	*/
2 /*	$NetBSD: fat.h,v 1.9 2014/10/18 08:33:28 snj Exp $	*/
3 
4 /*-
5  * Copyright (C) 1994, 1997 Wolfgang Solfrank.
6  * Copyright (C) 1994, 1997 TooLs GmbH.
7  * All rights reserved.
8  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by TooLs GmbH.
21  * 4. The name of TooLs GmbH may not be used to endorse or promote products
22  *    derived from this software without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
29  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
30  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
31  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
32  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
33  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 /*
36  * Written by Paul Popelka (paulp@uts.amdahl.com)
37  *
38  * You can do anything you want with this software, just don't say you wrote
39  * it, and don't remove this notice.
40  *
41  * This software is provided "as is".
42  *
43  * The author supplies this software to be publicly redistributed on the
44  * understanding that the author is not responsible for the correct
45  * functioning of this software in any circumstances and is not liable for
46  * any damages caused by this software.
47  *
48  * October 1992
49  */
50 
51 #ifndef _MSDOSFS_FAT_H_
52 #define _MSDOSFS_FAT_H_
53 /*
54  * Some useful cluster numbers.
55  */
56 #define	MSDOSFSROOT	0		/* cluster 0 means the root dir */
57 #define	CLUST_FREE	0		/* cluster 0 also means a free cluster */
58 #define	MSDOSFSFREE	CLUST_FREE
59 #define	CLUST_FIRST	2		/* first legal cluster number */
60 #define	CLUST_RSRVD	0xfffffff6	/* reserved cluster range */
61 #define	CLUST_BAD	0xfffffff7	/* a cluster with a defect */
62 #define	CLUST_EOFS	0xfffffff8	/* start of eof cluster range */
63 #define	CLUST_EOFE	0xffffffff	/* end of eof cluster range */
64 #define	CLUST_END	CLUST_EOFE	/* bigger than any valid cluster */
65 
66 #define	FAT12_MASK	0x00000fff	/* mask for 12 bit cluster numbers */
67 #define	FAT16_MASK	0x0000ffff	/* mask for 16 bit cluster numbers */
68 #define	FAT32_MASK	0x0fffffff	/* mask for FAT32 cluster numbers */
69 
70 /*
71  * MSDOSFS:
72  * Return true if filesystem uses 12 bit FATs. Microsoft Programmer's
73  * Reference says if the maximum cluster number in a filesystem is greater
74  * than 4084 ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK) then we've got a
75  * 16 bit FAT filesystem. While mounting, the result of this test is stored
76  * in pm_fatentrysize.
77  */
78 #define	FAT12(pmp)	(pmp->pm_fatmask == FAT12_MASK)
79 #define	FAT16(pmp)	(pmp->pm_fatmask == FAT16_MASK)
80 #define	FAT32(pmp)	(pmp->pm_fatmask == FAT32_MASK)
81 
82 /*
83  * M$ in its unlimited wisdom decided that EOF mark is anything
84  * between 0xfffffff8 and 0xffffffff (masked by appropriate fatmask,
85  * of course).
86  * Note that cn is supposed to be already adjusted accordingly to FAT type.
87  */
88 #define	MSDOSFSEOF(cn, fatmask)	\
89 	(((cn) & CLUST_EOFS) == (CLUST_EOFS & (fatmask)))
90 
91 /*
92  * These are the values for the function argument to the function
93  * fatentry().
94  */
95 #define	FAT_GET		0x0001	/* get a FAT entry */
96 #define	FAT_SET		0x0002	/* set a FAT entry */
97 #define	FAT_GET_AND_SET	(FAT_GET | FAT_SET)
98 
99 /*
100  * Flags to extendfile:
101  */
102 #define	DE_CLEAR	1	/* Zero out the blocks allocated */
103 
104 int pcbmap(struct denode *, u_long, daddr_t *, u_long *, int *);
105 int clusterfree(struct msdosfsmount *, u_long, u_long *);
106 int clusteralloc(struct msdosfsmount *, u_long, u_long,u_long *,u_long *);
107 int extendfile(struct denode *, u_long, struct mkfsbuf **, u_long *, int);
108 int fatentry(int, struct msdosfsmount *, u_long, u_long *, u_long);
109 void fc_purge(struct denode *, u_int);
110 void fc_lookup(struct denode *, u_long, u_long *, u_long *);
111 int fillinusemap(struct msdosfsmount *);
112 int freeclusterchain(struct msdosfsmount *, u_long);
113 #endif /* _MSDOSFS_FAT_H_ */
114