fat.h@ 106061

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1	/* $Id: fat.h 106061 2024-09-16 14:03:52Z vboxsync $ */
2	/** @file
3	* IPRT, File Allocation Table (FAT).
4	*/
5
6	/*
7	* Copyright (C) 2017-2024 Oracle and/or its affiliates.
8	*
9	* This file is part of VirtualBox base platform packages, as
10	* available from https://www.virtualbox.org.
11	*
12	* This program is free software; you can redistribute it and/or
13	* modify it under the terms of the GNU General Public License
14	* as published by the Free Software Foundation, in version 3 of the
15	* License.
16	*
17	* This program is distributed in the hope that it will be useful, but
18	* WITHOUT ANY WARRANTY; without even the implied warranty of
19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20	* General Public License for more details.
21	*
22	* You should have received a copy of the GNU General Public License
23	* along with this program; if not, see <https://www.gnu.org/licenses>.
24	*
25	* The contents of this file may alternatively be used under the terms
26	* of the Common Development and Distribution License Version 1.0
27	* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
28	* in the VirtualBox distribution, in which case the provisions of the
29	* CDDL are applicable instead of those of the GPL.
30	*
31	* You may elect to license modified versions of this file under the
32	* terms and conditions of either the GPL or the CDDL or both.
33	*
34	* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
35	*/
36
37	#ifndef IPRT_INCLUDED_formats_fat_h
38	#define IPRT_INCLUDED_formats_fat_h
39	#ifndef RT_WITHOUT_PRAGMA_ONCE
40	# pragma once
41	#endif
42
43	#include <iprt/types.h>
44	#include <iprt/assertcompile.h>
45
46
47	/** @defgroup grp_rt_formats_fat File Allocation Table (FAT) structures and definitions
48	* @ingroup grp_rt_formats
49	* @{
50	*/
51
52
53	/** @name FAT Media byte values
54	* @remarks This isn't as simple as it's made out to be here!
55	* @{ */
56	#define FATBPB_MEDIA_FLOPPY_8 UINT8_C(0xe5)
57	#define FATBPB_MEDIA_FLOPPY_5_DOT_25 UINT8_C(0xed)
58	#define FATBPB_MEDIA_FLOPPY_3_DOT_5 UINT8_C(0xf0)
59	/* incomplete, figure out as needed... */
60
61	/** Checks if @a a_bMedia is a valid media byte. */
62	#define FATBPB_MEDIA_IS_VALID(a_bMedia) ( (uint8_t)(a_bMedia) >= 0xf8 \
63	\|\| (uint8_t)(a_bMedia) == 0xf0 \
64	\|\| (uint8_t)(a_bMedia) == 0xf4 /* obscure - msdos 2.11 */ \
65	\|\| (uint8_t)(a_bMedia) == 0xf5 /* obscure - msdos 2.11 */ \
66	\|\| (uint8_t)(a_bMedia) == 0xed /* obscure - tandy 2000 */ \
67	\|\| (uint8_t)(a_bMedia) == 0xe5 /* obscure - tandy 2000 */ )
68	/** @} */
69
70	/** Checks if @a a_bFatId is a valid FAT ID byte.
71	* @todo uncertain whether 0xf4 and 0xf5 should be allowed here too. */
72	#define FAT_ID_IS_VALID(a_bFatId) ( (uint8_t)(a_bFatId) >= 0xf8 \
73	\|\| (uint8_t)(a_bFatId) == 0xf0 \
74	\|\| (uint8_t)(a_bFatId) == 0xf4 /* obscure - msdos 2.11 */ \
75	\|\| (uint8_t)(a_bFatId) == 0xf5 /* obscure - msdos 2.11 */ \
76	\|\| (uint8_t)(a_bFatId) == 0xed /* obscure, tandy 2000 */ \
77	\|\| (uint8_t)(a_bFatId) == 0xe5 /* obscure, tandy 2000 */ )
78
79	/**
80	* The DOS 2.0 BIOS parameter block (BPB).
81	*
82	* This was the first DOS version with a BPB.
83	*/
84	#pragma pack(1)
85	typedef struct FATBPB20
86	{
87	/** 0x0b / 0x00: The sector size in bytes. */
88	uint16_t cbSector;
89	/** 0x0d / 0x02: Number of sectors per cluster. */
90	uint8_t cSectorsPerCluster;
91	/** 0x0e / 0x03: Number of reserved sectors before the first FAT. */
92	uint16_t cReservedSectors;
93	/** 0x10 / 0x05: Number of FATs. */
94	uint8_t cFats;
95	/** 0x11 / 0x06: Max size of the root directory (0 for FAT32). */
96	uint16_t cMaxRootDirEntries;
97	/** 0x13 / 0x08: Total sector count, zero if 32-bit count is used. */
98	uint16_t cTotalSectors16;
99	/** 0x15 / 0x0a: Media ID. */
100	uint8_t bMedia;
101	/** 0x16 / 0x0b: Number of sectors per FAT (0 for FAT32). */
102	uint16_t cSectorsPerFat;
103	} FATBPB20;
104	#pragma pack()
105	AssertCompileSize(FATBPB20, 0xd);
106	/** Pointer to a DOS 2.0 BPB. */
107	typedef FATBPB20 *PFATBPB20;
108	/** Pointer to a const DOS 2.0 BPB. */
109	typedef FATBPB20 const *PCFATBPB20;
110
111
112	/**
113	* The DOS 3.0 BPB changes that survived.
114	*/
115	#pragma pack(1)
116	typedef struct FATBPB30CMN
117	{
118	/** DOS v2.0 BPB. */
119	FATBPB20 Bpb20;
120	/** 0x18 / 0x0d: Sectors per track. Zero means reserved and not used. */
121	uint16_t cSectorsPerTrack;
122	/** 0x1a / 0x0f: Number of heads. Zero means reserved and not used. */
123	uint16_t cTracksPerCylinder;
124	} FATBPB30CMN;
125	#pragma pack()
126	AssertCompileSize(FATBPB30CMN, 0x11);
127
128	/**
129	* The DOS 3.0 BPB.
130	*/
131	#pragma pack(1)
132	typedef struct FATBPB30
133	{
134	/** DOS v3.0 BPB bits that survived. */
135	FATBPB30CMN Core30;
136	/** 0x1c / 0x11: Number of hidden sectors preceeding the volume. This is zero
137	* on unpartitioned media. */
138	uint16_t cHiddenSectors;
139	} FATBPB30;
140	#pragma pack()
141	AssertCompileSize(FATBPB30, 0x13);
142	/** Pointer to a DOS 3.0 BPB. */
143	typedef FATBPB30 *PFATBPB30;
144	/** Pointer to a const DOS 3.0 BPB. */
145	typedef FATBPB30 const *PCFATBPB30;
146
147	/**
148	* The DOS 3.0 BPB, flattened structure.
149	*/
150	#pragma pack(1)
151	typedef struct FATBPB30FLAT
152	{
153	/** @name New in DOS 2.0
154	* @{ */
155	/** 0x0b / 0x00: The sector size in bytes. */
156	uint16_t cbSector;
157	/** 0x0d / 0x02: Number of sectors per cluster. */
158	uint8_t cSectorsPerCluster;
159	/** 0x0e / 0x03: Number of reserved sectors before the first FAT. */
160	uint16_t cReservedSectors;
161	/** 0x10 / 0x05: Number of FATs. */
162	uint8_t cFats;
163	/** 0x11 / 0x06: Max size of the root directory (0 for FAT32). */
164	uint16_t cMaxRootDirEntries;
165	/** 0x13 / 0x08: Total sector count, zero if 32-bit count is used. */
166	uint16_t cTotalSectors16;
167	/** 0x15 / 0x0a: Media ID. */
168	uint8_t bMedia;
169	/** 0x16 / 0x0b: Number of sectors per FAT (0 for FAT32). */
170	uint16_t cSectorsPerFat;
171	/** @} */
172	/** @name New in DOS 3.0
173	* @{ */
174	/** 0x18 / 0x0d: Sectors per track. Zero means reserved and not used. */
175	uint16_t cSectorsPerTrack;
176	/** 0x1a / 0x0f: Number of heads. Zero means reserved and not used. */
177	uint16_t cTracksPerCylinder;
178	/** 0x1c / 0x11: Number of hidden sectors preceeding the volume. This is zero
179	* on unpartitioned media. */
180	uint16_t cHiddenSectors;
181	/** @} */
182	} FATBPB30FLAT;
183	#pragma pack()
184	AssertCompileSize(FATBPB30FLAT, 0x13);
185	/** Pointer to a flattened DOS 3.0 BPB. */
186	typedef FATBPB30FLAT *PFATBPB30FLAT;
187	/** Pointer to a const flattened DOS 3.0 BPB. */
188	typedef FATBPB30FLAT const *PCFATBPB30FLAT;
189
190
191	/**
192	* The DOS 3.2 BPB.
193	*/
194	#pragma pack(1)
195	typedef struct FATBPB32
196	{
197	/** DOS v3.0 BPB. */
198	FATBPB30 Bpb30;
199	/** 0x1e / 0x13: Number of sectors, including the hidden ones. This is ZERO
200	* in DOS 3.31+. */
201	uint16_t cAnotherTotalSectors;
202	} FATBPB32;
203	#pragma pack()
204	AssertCompileSize(FATBPB32, 0x15);
205	/** Pointer to a DOS 3.2 BPB. */
206	typedef FATBPB32 *PFATBPB32;
207	/** Pointer to const a DOS 3.2 BPB. */
208	typedef FATBPB32 const *PCFATBPB32;
209
210	/**
211	* The DOS 3.2 BPB, flattened structure.
212	*/
213	#pragma pack(1)
214	typedef struct FATBPB32FLAT
215	{
216	/** @name New in DOS 2.0
217	* @{ */
218	/** 0x0b / 0x00: The sector size in bytes. */
219	uint16_t cbSector;
220	/** 0x0d / 0x02: Number of sectors per cluster. */
221	uint8_t cSectorsPerCluster;
222	/** 0x0e / 0x03: Number of reserved sectors before the first FAT. */
223	uint16_t cReservedSectors;
224	/** 0x10 / 0x05: Number of FATs. */
225	uint8_t cFats;
226	/** 0x11 / 0x06: Max size of the root directory (0 for FAT32). */
227	uint16_t cMaxRootDirEntries;
228	/** 0x13 / 0x08: Total sector count, zero if 32-bit count is used. */
229	uint16_t cTotalSectors16;
230	/** 0x15 / 0x0a: Media ID. */
231	uint8_t bMedia;
232	/** 0x16 / 0x0b: Number of sectors per FAT (0 for FAT32). */
233	uint16_t cSectorsPerFat;
234	/** @} */
235	/** @name New in DOS 3.0
236	* @{ */
237	/** 0x18 / 0x0d: Sectors per track. Zero means reserved and not used. */
238	uint16_t cSectorsPerTrack;
239	/** 0x1a / 0x0f: Number of heads. Zero means reserved and not used. */
240	uint16_t cTracksPerCylinder;
241	/** 0x1c / 0x11: Number of hidden sectors preceeding the volume. This is zero
242	* on unpartitioned media. */
243	uint16_t cHiddenSectors;
244	/** @} */
245	/** @name New in DOS 3.2
246	* @{ */
247	/** 0x1e / 0x13: Number of sectors, including the hidden ones. This is ZERO
248	* in DOS 3.31+. */
249	uint16_t cAnotherTotalSectors;
250	/** @} */
251	} FATBPB32FLAT;
252	#pragma pack()
253	AssertCompileSize(FATBPB32FLAT, 0x15);
254	/** Pointer to a flattened DOS 3.2 BPB. */
255	typedef FATBPB32FLAT *PFATBPB32FLAT;
256	/** Pointer to a const flattened DOS 3.2 BPB. */
257	typedef FATBPB32FLAT const *PCFATBPB32FLAT;
258
259
260	/**
261	* The DOS 3.31 BPB.
262	*/
263	#pragma pack(1)
264	typedef struct FATBPB331
265	{
266	/** DOS v3.0 BPB bits that survived. */
267	FATBPB30CMN Core30;
268	/** 0x1c / 0x11: Number of hidden sectors preceeding the volume. This is zero
269	* on unpartitioned media. Values higher than 65535 are complicated due to
270	* the field overlapping FATBPB32::cAnotherTotalSectors */
271	uint32_t cHiddenSectors;
272	/** 0x20 / 0x15: Total logical sectors. Used if count >= 64K, otherwise
273	* FATBPB20::cTotalSectors16 is used. Zero if 64-bit value used with FAT32. */
274	uint32_t cTotalSectors32;
275	} FATBPB331;
276	#pragma pack()
277	AssertCompileSize(FATBPB331, 0x19);
278	/** Pointer to a DOS 3.31 BPB. */
279	typedef FATBPB331 *PFATBPB331;
280	/** Pointer to a const DOS 3.31 BPB. */
281	typedef FATBPB331 const *PCFATBPB331;
282
283	/**
284	* The DOS 3.31 BPB, flattened structure.
285	*/
286	#pragma pack(1)
287	typedef struct FATBPB331FLAT
288	{
289	/** @name New in DOS 2.0
290	* @{ */
291	/** 0x0b / 0x00: The sector size in bytes. */
292	uint16_t cbSector;
293	/** 0x0d / 0x02: Number of sectors per cluster. */
294	uint8_t cSectorsPerCluster;
295	/** 0x0e / 0x03: Number of reserved sectors before the first FAT (0 for
296	* NTFS). */
297	uint16_t cReservedSectors;
298	/** 0x10 / 0x05: Number of FATs (0 for NTFS). */
299	uint8_t cFats;
300	/** 0x11 / 0x06: Max size of the root directory (0 for FAT32 & NTFS). */
301	uint16_t cMaxRootDirEntries;
302	/** 0x13 / 0x08: Total sector count, zero if 32-bit count is used (and for
303	* NTFS). */
304	uint16_t cTotalSectors16;
305	/** 0x15 / 0x0a: Media ID. */
306	uint8_t bMedia;
307	/** 0x16 / 0x0b: Number of sectors per FAT (0 for FAT32 & NTFS). */
308	uint16_t cSectorsPerFat;
309	/** @} */
310	/** @name New in DOS 3.0
311	* @{ */
312	/** 0x18 / 0x0d: Sectors per track. Zero means reserved and not used. */
313	uint16_t cSectorsPerTrack;
314	/** 0x1a / 0x0f: Number of heads. Zero means reserved and not used. */
315	uint16_t cTracksPerCylinder;
316	/** @} */
317	/** @name New in DOS 3.31
318	* @{ */
319	/** 0x1c / 0x11: Number of hidden sectors preceeding the volume. This is zero
320	* on unpartitioned media. Values higher than 65535 are complicated due to
321	* the field overlapping FATBPB32::cAnotherTotalSectors */
322	uint32_t cHiddenSectors;
323	/** 0x20 / 0x15: Total logical sectors. Used if count >= 64K, otherwise
324	* FATBPB20::cTotalSectors16 is used. Zero if 64-bit value used with FAT32.
325	* (Zero for NTFS). */
326	uint32_t cTotalSectors32;
327	/** @} */
328	} FATBPB331FLAT;
329	#pragma pack()
330	AssertCompileSize(FATBPB331FLAT, 0x19);
331	/** Pointer to a flattened DOS 3.31 BPB. */
332	typedef FATBPB331FLAT *PFATBPB331FLAT;
333	/** Pointer to a const flattened DOS 3.31 BPB. */
334	typedef FATBPB331FLAT const *PCFATBPB331FLAT;
335
336
337	/**
338	* Extended BIOS parameter block (EBPB).
339	*/
340	#pragma pack(1)
341	typedef struct FATEBPB
342	{
343	/** The BPB. */
344	FATBPB331FLAT Bpb;
345
346	/** 0x24 / 0x19: BIOS INT13 pysical drive number. */
347	uint8_t bInt13Drive;
348	/** 0x25 / 0x1a: Reserved. NT used bit 0 for indicating dirty FS, and bit 1
349	* for surface scan. */
350	uint8_t bReserved;
351	/** 0x26 / 0x1b: Extended boot signature, FATEBPB_SIGNATURE or
352	* FATEBPB_SIGNATURE_OLD. */
353	uint8_t bExtSignature;
354	/** 0x27 / 0x1c: The volume serial number. */
355	uint32_t uSerialNumber;
356	/** 0x2b / 0x20: The volume label (space padded).
357	* @remarks Not available with FATEBPB_SIGNATURE_OLD */
358	char achLabel[11];
359	/** 0x36 / 0x2b: The file system type (space padded).
360	* @remarks Not available with FATEBPB_SIGNATURE_OLD */
361	char achType[8];
362	} FATEBPB;
363	#pragma pack()
364	AssertCompileSize(FATEBPB, 0x33);
365	/** Pointer to an extended BIOS parameter block. */
366	typedef FATEBPB *PFATEBPB;
367	/** Pointer to a const extended BIOS parameter block. */
368	typedef FATEBPB const *PCFATEBPB;
369
370	/** FATEBPB::bExtSignature value. */
371	#define FATEBPB_SIGNATURE UINT8_C(0x29)
372	/** FATEBPB::bExtSignature value used by OS/2 1.0-1.1 and PC DOS 3.4. These
373	* does not have the volume and file system type. */
374	#define FATEBPB_SIGNATURE_OLD UINT8_C(0x28)
375
376	/*FATEBPB::achType value for FAT12. /
377	#define FATEBPB_TYPE_FAT12 "FAT12 "
378	/*FATEBPB::achType value for FAT16. /
379	#define FATEBPB_TYPE_FAT16 "FAT16 "
380	/*FATEBPB::achType value for FAT12/FAT16. /
381	#define FATEBPB_TYPE_FAT "FAT32 "
382
383
384	/**
385	* FAT32 Extended BIOS parameter block (EBPB).
386	*/
387	#pragma pack(1)
388	typedef struct FAT32EBPB
389	{
390	/** The BPB. */
391	FATBPB331FLAT Bpb;
392
393	/** 0x24 / 0x19: Number of sectors per FAT.
394	* @note To avoid confusion with the FATEBPB signature, values which result in
395	* 0x00280000 or 0x00290000 when masked by 0x00ff0000 must not be used. */
396	uint32_t cSectorsPerFat32;
397	/** 0x28 / 0x1d: Flags pertaining to FAT mirroring and other stuff. */
398	uint16_t fFlags;
399	/** 0x2a / 0x1f: FAT32 version number (FAT32EBPB_VERSION_0_0). */
400	uint16_t uVersion;
401	/** 0x2c / 0x21: Cluster number of the root directory. */
402	uint32_t uRootDirCluster;
403	/** 0x30 / 0x25: Logical sector number of the information sector. */
404	uint16_t uInfoSectorNo;
405	/** 0x32 / 0x27: Logical sector number of boot sector copy. */
406	uint16_t uBootSectorCopySectorNo;
407	/** 0x34 / 0x29: Reserved, zero (or 0xf6) filled, preserve. */
408	uint8_t abReserved[12];
409
410	/** 0x40 / 0x35: BIOS INT13 pysical drive number
411	* @remarks Same as FATEBPB::bInt13Drive. */
412	uint8_t bInt13Drive;
413	/** 0x41 / 0x36: Reserved.
414	* @remarks Same as FATEBPB::bReserved. */
415	uint8_t bReserved;
416	/** 0x42 / 0x37: Extended boot signature (FATEBPB_SIGNATURE, or
417	* FATEBPB_SIGNATURE_OLD in some special cases).
418	* @remarks Same as FATEBPB::bExtSignature. */
419	uint8_t bExtSignature;
420	/** 0x43 / 0x38: The volume serial number.
421	* @remarks Same as FATEBPB::uSerialNumber. */
422	uint32_t uSerialNumber;
423	/** 0x47 / 0x3c: The volume label (space padded).
424	* @remarks Not available with FATEBPB_SIGNATURE_OLD
425	* @remarks Same as FATEBPB::achLabel. */
426	char achLabel[11];
427	/** 0x52 / 0x47: The file system type (space padded), or 64-bit logical sector
428	* count if both other count fields are zero. In the latter case, the type is
429	* moved to the OEM name field (FATBOOTSECTOR::achOemName).
430	*
431	* @remarks Not available with FATEBPB_SIGNATURE_OLD
432	* @remarks Same as FATEBPB::achType. */
433	union
434	{
435	/** Type string variant. */
436	char achType[8];
437	/** Total sector count if 4G or higher. */
438	uint64_t cTotalSectors64;
439	} u;
440	} FAT32EBPB;
441	#pragma pack()
442	AssertCompileSize(FAT32EBPB, 0x4f);
443	/** Pointer to a FAT32 extended BIOS parameter block. */
444	typedef FAT32EBPB *PFAT32EBPB;
445	/** Pointer to a const FAT32 extended BIOS parameter block. */
446	typedef FAT32EBPB const *PCFAT32EBPB;
447
448	/** FAT32 version 0.0 (FAT32EBPB::uVersion). */
449	#define FAT32EBPB_VERSION_0_0 UINT16_C(0x0000)
450
451
452	/**
453	* NTFS extended BIOS parameter block (NTFSEBPB).
454	*/
455	#pragma pack(1)
456	typedef struct NTFSEBPB
457	{
458	/** The BPB. */
459	FATBPB331FLAT Bpb;
460
461	/** 0x24 / 0x19: BIOS INT13 pysical drive number.
462	* @note Same location as FATEBPB::bInt13Drive. */
463	uint8_t bInt13Drive;
464	/** 0x25 / 0x1a: Reserved / flags */
465	uint8_t bReserved;
466	/** 0x26 / 0x1b: Extended boot signature (NTFSEBPB_SIGNATURE).
467	* @note Same location as FATEBPB::bExtSignature. */
468	uint8_t bExtSignature;
469	/** 0x27 / 0x1c: Reserved */
470	uint8_t bReserved2;
471
472	/** 0x28 / 0x1d: Number of sectors. */
473	uint64_t cSectors;
474	/** 0x30 / 0x25: Logical cluster number of the master file table (MFT). */
475	uint64_t uLcnMft;
476	/** 0x38 / 0x2d: Logical cluster number of the MFT mirror. */
477	uint64_t uLcnMftMirror;
478	/** 0x40 / 0x35: Logical clusters per file record segment.
479	* This is a shift count if negative. */
480	int8_t cClustersPerMftRecord;
481	/** 0x41 / 0x36: Reserved. */
482	uint8_t abReserved3[3];
483	/** 0x44 / 0x39: The default logical clusters count per index node.
484	* This is a shift count if negative. */
485	int8_t cClustersPerIndexNode;
486	/** 0x45 / 0x3a: Reserved. */
487	uint8_t abReserved4[3];
488	/** 0x48 / 0x3d: Volume serial number.
489	* @note This is larger than the the FAT serial numbers. */
490	uint64_t uSerialNumber;
491	/** 0x50 / 0x45: Checksum. */
492	uint32_t uChecksum;
493	} NTFSEBPB;
494	#pragma pack()
495	AssertCompileSize(NTFSEBPB, 0x49);
496	/** Pointer to a NTFS extended BIOS parameter block. */
497	typedef NTFSEBPB *PNTFSEBPB;
498	/** Pointer to a const NTFS extended BIOS parameter block. */
499	typedef NTFSEBPB const *PCNTFSEBPB;
500
501	/** NTFS EBPB signature (NTFSEBPB::bExtSignature). */
502	#define NTFSEBPB_SIGNATURE UINT8_C(0x80)
503
504
505	/**
506	* FAT boot sector layout.
507	*/
508	#pragma pack(1)
509	typedef struct FATBOOTSECTOR
510	{
511	/** 0x000: DOS 2.0+ jump sequence. */
512	uint8_t abJmp[3];
513	/** 0x003: OEM name (who formatted this volume). */
514	char achOemName[8];
515	/** 0x00b: The BIOS parameter block.
516	* This varies a lot in size. */
517	union
518	{
519	FATBPB20 Bpb20;
520	FATBPB30FLAT Bpb30;
521	FATBPB32FLAT Bpb32;
522	FATBPB331FLAT Bpb331;
523	FATEBPB Ebpb;
524	FAT32EBPB Fat32Ebpb;
525	NTFSEBPB Ntfs;
526	} Bpb;
527	/** 0x05a: Bootloader code/data/stuff. */
528	uint8_t abStuff[0x1a3];
529	/** 0x1fd: Old drive number location (DOS 3.2-3.31). */
530	uint8_t bOldInt13Drive;
531	/** 0x1fe: DOS signature (FATBOOTSECTOR_SIGNATURE). */
532	uint16_t uSignature;
533	} FATBOOTSECTOR;
534	#pragma pack()
535	AssertCompileSize(FATBOOTSECTOR, 0x200);
536	/** Pointer to a FAT boot sector. */
537	typedef FATBOOTSECTOR *PFATBOOTSECTOR;
538	/** Pointer to a const FAT boot sector. */
539	typedef FATBOOTSECTOR const *PCFATBOOTSECTOR;
540
541	/** Boot sector signature (FATBOOTSECTOR::uSignature). */
542	#define FATBOOTSECTOR_SIGNATURE UINT16_C(0xaa55)
543
544
545
546	/**
547	* FAT32 info sector (follows the boot sector).
548	*/
549	typedef struct FAT32INFOSECTOR
550	{
551	/** 0x000: Signature \#1 (FAT32INFOSECTOR_SIGNATURE_1). */
552	uint32_t uSignature1;
553	/** Reserved, should be zero. */
554	uint8_t abReserved1[0x1E0];
555	/** 0x1e4: Signature \#1 (FAT32INFOSECTOR_SIGNATURE_2). */
556	uint32_t uSignature2;
557	/** 0x1e8: Last known number of free clusters (informational). */
558	uint32_t cFreeClusters;
559	/** 0x1ec: Last allocated cluster number (informational). This could be used as
560	* an allocation hint when searching for a free cluster. */
561	uint32_t cLastAllocatedCluster;
562	/** 0x1f0: Reserved, should be zero, preserve. */
563	uint8_t abReserved2[12];
564	/** 0x1fc: Signature \#3 (FAT32INFOSECTOR_SIGNATURE_3). */
565	uint32_t uSignature3;
566	} FAT32INFOSECTOR;
567	AssertCompileSize(FAT32INFOSECTOR, 0x200);
568	/** Pointer to a FAT32 info sector. */
569	typedef FAT32INFOSECTOR *PFAT32INFOSECTOR;
570	/** Pointer to a const FAT32 info sector. */
571	typedef FAT32INFOSECTOR const *PCFAT32INFOSECTOR;
572
573	#define FAT32INFOSECTOR_SIGNATURE_1 UINT32_C(0x41615252)
574	#define FAT32INFOSECTOR_SIGNATURE_2 UINT32_C(0x61417272)
575	#define FAT32INFOSECTOR_SIGNATURE_3 UINT32_C(0xaa550000)
576
577
578	/** @name Special FAT cluster numbers and limits.
579	* @{ */
580	#define FAT_FIRST_DATA_CLUSTER 2 /*< The first data cluster. /
581
582	#define FAT_MAX_FAT12_TOTAL_CLUSTERS UINT32_C(0x00000ff6) /*< Maximum number of clusters in a 12-bit FAT . /
583	#define FAT_MAX_FAT16_TOTAL_CLUSTERS UINT32_C(0x0000fff6) /*< Maximum number of clusters in a 16-bit FAT . /
584	#define FAT_MAX_FAT32_TOTAL_CLUSTERS UINT32_C(0x0ffffff6) /*< Maximum number of clusters in a 32-bit FAT . /
585
586	#define FAT_LAST_FAT12_DATA_CLUSTER UINT32_C(0x00000ff5) /*< The last possible data cluster for FAT12. /
587	#define FAT_LAST_FAT16_DATA_CLUSTER UINT32_C(0x0000fff5) /*< The last possible data cluster for FAT16. /
588	#define FAT_LAST_FAT32_DATA_CLUSTER UINT32_C(0x0ffffff5) /*< The last possible data cluster for FAT32. /
589
590	#define FAT_MAX_FAT12_DATA_CLUSTERS UINT32_C(0x00000ff4) /*< Maximum number of data clusters for FAT12. /
591	#define FAT_MAX_FAT16_DATA_CLUSTERS UINT32_C(0x0000fff4) /*< Maximum number of data clusters for FAT16. /
592	#define FAT_MAX_FAT32_DATA_CLUSTERS UINT32_C(0x0ffffff4) /*< Maximum number of data clusters for FAT32. /
593
594	#define FAT_MIN_FAT12_DATA_CLUSTERS UINT32_C(0x00000001) /*< Maximum number of data clusters for FAT12. /
595	#define FAT_MIN_FAT16_DATA_CLUSTERS UINT32_C(0x00000ff5) /*< Maximum number of data clusters for FAT16. /
596	#define FAT_MIN_FAT32_DATA_CLUSTERS UINT32_C(0x0000fff5) /*< Maximum number of data clusters for FAT32. /
597
598	#define FAT_FIRST_FAT12_EOC UINT32_C(0x00000ff8) /*< The first end-of-file-cluster number for FAT12. /
599	#define FAT_FIRST_FAT16_EOC UINT32_C(0x0000fff8) /*< The first end-of-file-cluster number for FAT16. /
600	#define FAT_FIRST_FAT32_EOC UINT32_C(0x0ffffff8) /*< The first end-of-file-cluster number for FAT32. /
601	/** @} */
602
603
604	/**
605	* FAT directory entry.
606	*/
607	typedef struct FATDIRENTRY
608	{
609	/** 0x00: The directory entry name.
610	* First character serves as a flag to indicate deleted or not. */
611	uint8_t achName[8+3];
612	/** 0x0b: Attributes (FAT_ATTR_XXX). */
613	uint8_t fAttrib;
614	/** 0x0c: NT case flags (FATDIRENTRY_CASE_F_XXX). */
615	uint8_t fCase;
616	/** 0x0d: Birth milliseconds (DOS 7.0+ w/VFAT). */
617	uint8_t uBirthCentiseconds;
618	/** 0x0e: Birth time (DOS 7.0+ w/VFAT). */
619	uint16_t uBirthTime;
620	/** 0x10: Birth date (DOS 7.0+ w/VFAT). */
621	uint16_t uBirthDate;
622	/** 0x12: Access date (DOS 7.0+ w/ACCDATA in Config.sys). */
623	uint16_t uAccessDate;
624	union
625	{
626	/** 0x14: High cluster word for FAT32. */
627	uint16_t idxClusterHigh;
628	/** 0x14: Index of extended attributes (FAT16/FAT12). */
629	uint16_t idxEAs;
630	} u;
631	/** 0x16: Modify time (PC-DOS 1.1+, MS-DOS 1.20+). */
632	uint16_t uModifyTime;
633	/** 0x18: Modify date. */
634	uint16_t uModifyDate;
635	/** 0x1a: The data cluster index. */
636	uint16_t idxCluster;
637	/** 0x1c: The file size. */
638	uint32_t cbFile;
639	} FATDIRENTRY;
640	AssertCompileSize(FATDIRENTRY, 0x20);
641	AssertCompileMemberOffset(FATDIRENTRY, fAttrib, 0x0b);
642	AssertCompileMemberOffset(FATDIRENTRY, fCase, 0x0c);
643	AssertCompileMemberOffset(FATDIRENTRY, uBirthCentiseconds, 0x0d);
644	AssertCompileMemberOffset(FATDIRENTRY, uBirthTime, 0x0e);
645	AssertCompileMemberOffset(FATDIRENTRY, uBirthDate, 0x10);
646	AssertCompileMemberOffset(FATDIRENTRY, uAccessDate, 0x12);
647	AssertCompileMemberOffset(FATDIRENTRY, u, 0x14);
648	AssertCompileMemberOffset(FATDIRENTRY, uModifyTime, 0x16);
649	AssertCompileMemberOffset(FATDIRENTRY, uModifyDate, 0x18);
650	AssertCompileMemberOffset(FATDIRENTRY, idxCluster, 0x1a);
651	AssertCompileMemberOffset(FATDIRENTRY, cbFile, 0x1c);
652	/** Pointer to a FAT directory entry. */
653	typedef FATDIRENTRY *PFATDIRENTRY;
654	/** Pointer to a FAT directory entry. */
655	typedef FATDIRENTRY const *PCFATDIRENTRY;
656
657
658	/** @name FAT_ATTR_XXX - FATDIRENTRY::fAttrib flags.
659	* @{ */
660	#define FAT_ATTR_READONLY UINT8_C(0x01)
661	#define FAT_ATTR_HIDDEN UINT8_C(0x02)
662	#define FAT_ATTR_SYSTEM UINT8_C(0x04)
663	#define FAT_ATTR_VOLUME UINT8_C(0x08)
664	#define FAT_ATTR_DIRECTORY UINT8_C(0x10)
665	#define FAT_ATTR_ARCHIVE UINT8_C(0x20)
666	#define FAT_ATTR_DEVICE UINT8_C(0x40)
667	#define FAT_ATTR_RESERVED UINT8_C(0x80)
668	#define FAT_ATTR_NAME_SLOT UINT8_C(0x0f) /*< Special attribute value for FATDIRNAMESLOT. /
669	/** @} */
670
671	/** @name FATDIRENTRY_CASE_F_XXX - FATDIRENTRY::fCase flags.
672	* @{ */
673	/** Lower cased base name (first 8 chars). */
674	#define FATDIRENTRY_CASE_F_LOWER_BASE UINT8_C(0x08)
675	/** Lower cased filename extension (last 3 chars). */
676	#define FATDIRENTRY_CASE_F_LOWER_EXT UINT8_C(0x10)
677	/** @} */
678
679	/** @name FATDIRENTRY_CH0_XXX - FATDIRENTRY::achName[0]
680	* @{ */
681	/** Deleted entry. */
682	#define FATDIRENTRY_CH0_DELETED UINT8_C(0xe5)
683	/** End of used directory entries (MS-DOS 1.25+, PC-DOS 2.0+). */
684	#define FATDIRENTRY_CH0_END_OF_DIR UINT8_C(0x00)
685	/** The special dot or dot-dot dir aliases (MS-DOS 1.40+, PC-DOS 2.0+).
686	* @remarks 0x2e is the ascii table entry of the '.' character. */
687	#define FATDIRENTRY_CH0_DOT_ALIAS UINT8_C(0x2e)
688	/** Escaped 0xe5 leadcharacter (DOS 3.0+). */
689	#define FATDIRENTRY_CH0_ESC_E5 UINT8_C(0x05)
690	/** @} */
691
692
693	/**
694	* FAT directory alias name slot.
695	*
696	* Each slot holds 13 UTF-16 (/ UCS-2) characters, so it takes 20 slots to cover
697	* a 255 character long name.
698	*/
699	#pragma pack(1)
700	typedef struct FATDIRNAMESLOT
701	{
702	/** The slot sequence number. */
703	uint8_t idSlot;
704	/** The first 5 name chars.
705	* @remarks misaligned */
706	RTUTF16 awcName0[5];
707	/** Attributes (FAT_ATTR_XXX). */
708	uint8_t fAttrib;
709	/** Always zero. */
710	uint8_t fZero;
711	/** Alias checksum. */
712	uint8_t bChecksum;
713	/** The next 6 name chars. */
714	RTUTF16 awcName1[6];
715	/** Always zero (usually cluster entry). */
716	uint16_t idxZero;
717	/** The next 2 name chars. */
718	RTUTF16 awcName2[2];
719	} FATDIRNAMESLOT;
720	#pragma pack()
721	AssertCompileSize(FATDIRNAMESLOT, 0x20);
722	/** Pointer to a FAT directory entry. */
723	typedef FATDIRNAMESLOT *PFATDIRNAMESLOT;
724	/** Pointer to a FAT directory entry. */
725	typedef FATDIRNAMESLOT const *PCFATDIRNAMESLOT;
726
727	/** Slot ID flag indicating that it's the first slot. */
728	#define FATDIRNAMESLOT_FIRST_SLOT_FLAG UINT8_C(0x40)
729	/** Highest slot ID recognized. This allows for 260 characters, however many
730	* implementation limits it to 255 or 250. */
731	#define FATDIRNAMESLOT_HIGHEST_SLOT_ID UINT8_C(0x14)
732	/** Max number of slots recognized. (This is the same as the higest slot ID
733	* because the 0 isn't a valid ID.) */
734	#define FATDIRNAMESLOT_MAX_SLOTS FATDIRNAMESLOT_HIGHEST_SLOT_ID
735	/** Number of UTF-16 units per slot. */
736	#define FATDIRNAMESLOT_CHARS_PER_SLOT (5 + 6 + 2)
737
738
739
740	/**
741	* FAT directory entry union.
742	*/
743	typedef union FATDIRENTRYUNION
744	{
745	/** Regular entry view. */
746	FATDIRENTRY Entry;
747	/** Name slot view. */
748	FATDIRNAMESLOT Slot;
749	} FATDIRENTRYUNION;
750	AssertCompileSize(FATDIRENTRYUNION, 0x20);
751	/** Pointer to a FAT directory entry union. */
752	typedef FATDIRENTRYUNION *PFATDIRENTRYUNION;
753	/** Pointer to a const FAT directory entry union. */
754	typedef FATDIRENTRYUNION const *PCFATDIRENTRYUNION;
755
756	/** @} */
757
758	#endif /* !IPRT_INCLUDED_formats_fat_h */
759

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source: vbox/trunk/include/iprt/formats/fat.h@ 106061

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