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17f341c87ec7c38ad397ed8e976a0c6728631387
[reactos.git] / boot / freeldr / freeldr / lib / fs / fat.c
1 /*
2 * FreeLoader
3 * Copyright (C) 1998-2003 Brian Palmer <brianp@sginet.com>
4 * Copyright (C) 2009 Hervé Poussineau
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License along
17 * with this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
19 */
20
21 #include <freeldr.h>
22
23 #include <debug.h>
24
25 DBG_DEFAULT_CHANNEL(FILESYSTEM);
26
27 ULONG FatDetermineFatType(PFAT_BOOTSECTOR FatBootSector, ULONGLONG PartitionSectorCount);
28 PVOID FatBufferDirectory(PFAT_VOLUME_INFO Volume, ULONG DirectoryStartCluster, ULONG* EntryCountPointer, BOOLEAN RootDirectory);
29 BOOLEAN FatSearchDirectoryBufferForFile(PFAT_VOLUME_INFO Volume, PVOID DirectoryBuffer, ULONG EntryCount, PCHAR FileName, PFAT_FILE_INFO FatFileInfoPointer);
30 ARC_STATUS FatLookupFile(PFAT_VOLUME_INFO Volume, PCSTR FileName, ULONG DeviceId, PFAT_FILE_INFO FatFileInfoPointer);
31 void FatParseShortFileName(PCHAR Buffer, PDIRENTRY DirEntry);
32 BOOLEAN FatGetFatEntry(PFAT_VOLUME_INFO Volume, ULONG Cluster, ULONG* ClusterPointer);
33 ULONG FatCountClustersInChain(PFAT_VOLUME_INFO Volume, ULONG StartCluster);
34 ULONG* FatGetClusterChainArray(PFAT_VOLUME_INFO Volume, ULONG StartCluster);
35 BOOLEAN FatReadClusterChain(PFAT_VOLUME_INFO Volume, ULONG StartClusterNumber, ULONG NumberOfClusters, PVOID Buffer);
36 BOOLEAN FatReadPartialCluster(PFAT_VOLUME_INFO Volume, ULONG ClusterNumber, ULONG StartingOffset, ULONG Length, PVOID Buffer);
37 BOOLEAN FatReadVolumeSectors(PFAT_VOLUME_INFO Volume, ULONG SectorNumber, ULONG SectorCount, PVOID Buffer);
38
39 #define TAG_FAT_CHAIN 'CtaT'
40 #define TAG_FAT_FILE 'FtaF'
41 #define TAG_FAT_VOLUME 'VtaF'
42 #define TAG_FAT_BUFFER 'BtaF'
43
44 typedef struct _FAT_VOLUME_INFO
45 {
46 ULONG BytesPerSector; /* Number of bytes per sector */
47 ULONG SectorsPerCluster; /* Number of sectors per cluster */
48 ULONG FatSectorStart; /* Starting sector of 1st FAT table */
49 ULONG ActiveFatSectorStart; /* Starting sector of active FAT table */
50 ULONG NumberOfFats; /* Number of FAT tables */
51 ULONG SectorsPerFat; /* Sectors per FAT table */
52 ULONG RootDirSectorStart; /* Starting sector of the root directory (non-fat32) */
53 ULONG RootDirSectors; /* Number of sectors of the root directory (non-fat32) */
54 ULONG RootDirStartCluster; /* Starting cluster number of the root directory (fat32 only) */
55 ULONG DataSectorStart; /* Starting sector of the data area */
56 ULONG FatType; /* FAT12, FAT16, FAT32, FATX16 or FATX32 */
57 ULONG DeviceId;
58 } FAT_VOLUME_INFO;
59
60 PFAT_VOLUME_INFO FatVolumes[MAX_FDS];
61
62 VOID FatSwapFatBootSector(PFAT_BOOTSECTOR Obj)
63 {
64 SW(Obj, BytesPerSector);
65 SW(Obj, ReservedSectors);
66 SW(Obj, RootDirEntries);
67 SW(Obj, TotalSectors);
68 SW(Obj, SectorsPerFat);
69 SW(Obj, SectorsPerTrack);
70 SW(Obj, NumberOfHeads);
71 SD(Obj, HiddenSectors);
72 SD(Obj, TotalSectorsBig);
73 SD(Obj, VolumeSerialNumber);
74 SW(Obj, BootSectorMagic);
75 }
76
77 VOID FatSwapFat32BootSector(PFAT32_BOOTSECTOR Obj)
78 {
79 SW(Obj, BytesPerSector);
80 SW(Obj, ReservedSectors);
81 SW(Obj, RootDirEntries);
82 SW(Obj, TotalSectors);
83 SW(Obj, SectorsPerFat);
84 SW(Obj, NumberOfHeads);
85 SD(Obj, HiddenSectors);
86 SD(Obj, TotalSectorsBig);
87 SD(Obj, SectorsPerFatBig);
88 SW(Obj, ExtendedFlags);
89 SW(Obj, FileSystemVersion);
90 SD(Obj, RootDirStartCluster);
91 SW(Obj, FsInfo);
92 SW(Obj, BackupBootSector);
93 SD(Obj, VolumeSerialNumber);
94 SW(Obj, BootSectorMagic);
95 }
96
97 VOID FatSwapFatXBootSector(PFATX_BOOTSECTOR Obj)
98 {
99 SD(Obj, VolumeSerialNumber);
100 SD(Obj, SectorsPerCluster);
101 SW(Obj, NumberOfFats);
102 }
103
104 VOID FatSwapDirEntry(PDIRENTRY Obj)
105 {
106 SW(Obj, CreateTime);
107 SW(Obj, CreateDate);
108 SW(Obj, LastAccessDate);
109 SW(Obj, ClusterHigh);
110 SW(Obj, Time);
111 SW(Obj, Date);
112 SW(Obj, ClusterLow);
113 SD(Obj, Size);
114 }
115
116 VOID FatSwapLFNDirEntry(PLFN_DIRENTRY Obj)
117 {
118 int i;
119 SW(Obj, StartCluster);
120 for(i = 0; i < 5; i++)
121 Obj->Name0_4[i] = SWAPW(Obj->Name0_4[i]);
122 for(i = 0; i < 6; i++)
123 Obj->Name5_10[i] = SWAPW(Obj->Name5_10[i]);
124 for(i = 0; i < 2; i++)
125 Obj->Name11_12[i] = SWAPW(Obj->Name11_12[i]);
126 }
127
128 VOID FatSwapFatXDirEntry(PFATX_DIRENTRY Obj)
129 {
130 SD(Obj, StartCluster);
131 SD(Obj, Size);
132 SW(Obj, Time);
133 SW(Obj, Date);
134 SW(Obj, CreateTime);
135 SW(Obj, CreateDate);
136 SW(Obj, LastAccessTime);
137 SW(Obj, LastAccessDate);
138 }
139
140 BOOLEAN FatOpenVolume(PFAT_VOLUME_INFO Volume, PFAT_BOOTSECTOR BootSector, ULONGLONG PartitionSectorCount)
141 {
142 char ErrMsg[80];
143 ULONG FatSize;
144 PFAT_BOOTSECTOR FatVolumeBootSector;
145 PFAT32_BOOTSECTOR Fat32VolumeBootSector;
146 PFATX_BOOTSECTOR FatXVolumeBootSector;
147
148 TRACE("FatOpenVolume() DeviceId = %d\n", Volume->DeviceId);
149
150 //
151 // Allocate the memory to hold the boot sector
152 //
153 FatVolumeBootSector = (PFAT_BOOTSECTOR)BootSector;
154 Fat32VolumeBootSector = (PFAT32_BOOTSECTOR)BootSector;
155 FatXVolumeBootSector = (PFATX_BOOTSECTOR)BootSector;
156
157 // Get the FAT type
158 Volume->FatType = FatDetermineFatType(FatVolumeBootSector, PartitionSectorCount);
159
160 // Dump boot sector (and swap it for big endian systems)
161 TRACE("Dumping boot sector:\n");
162 if (ISFATX(Volume->FatType))
163 {
164 FatSwapFatXBootSector(FatXVolumeBootSector);
165 TRACE("sizeof(FATX_BOOTSECTOR) = 0x%x.\n", sizeof(FATX_BOOTSECTOR));
166
167 TRACE("FileSystemType: %c%c%c%c.\n", FatXVolumeBootSector->FileSystemType[0], FatXVolumeBootSector->FileSystemType[1], FatXVolumeBootSector->FileSystemType[2], FatXVolumeBootSector->FileSystemType[3]);
168 TRACE("VolumeSerialNumber: 0x%x\n", FatXVolumeBootSector->VolumeSerialNumber);
169 TRACE("SectorsPerCluster: %d\n", FatXVolumeBootSector->SectorsPerCluster);
170 TRACE("NumberOfFats: %d\n", FatXVolumeBootSector->NumberOfFats);
171 TRACE("Unknown: 0x%x\n", FatXVolumeBootSector->Unknown);
172
173 TRACE("FatType %s\n", Volume->FatType == FATX16 ? "FATX16" : "FATX32");
174
175 }
176 else if (Volume->FatType == FAT32)
177 {
178 FatSwapFat32BootSector(Fat32VolumeBootSector);
179 TRACE("sizeof(FAT32_BOOTSECTOR) = 0x%x.\n", sizeof(FAT32_BOOTSECTOR));
180
181 TRACE("JumpBoot: 0x%x 0x%x 0x%x\n", Fat32VolumeBootSector->JumpBoot[0], Fat32VolumeBootSector->JumpBoot[1], Fat32VolumeBootSector->JumpBoot[2]);
182 TRACE("OemName: %c%c%c%c%c%c%c%c\n", Fat32VolumeBootSector->OemName[0], Fat32VolumeBootSector->OemName[1], Fat32VolumeBootSector->OemName[2], Fat32VolumeBootSector->OemName[3], Fat32VolumeBootSector->OemName[4], Fat32VolumeBootSector->OemName[5], Fat32VolumeBootSector->OemName[6], Fat32VolumeBootSector->OemName[7]);
183 TRACE("BytesPerSector: %d\n", Fat32VolumeBootSector->BytesPerSector);
184 TRACE("SectorsPerCluster: %d\n", Fat32VolumeBootSector->SectorsPerCluster);
185 TRACE("ReservedSectors: %d\n", Fat32VolumeBootSector->ReservedSectors);
186 TRACE("NumberOfFats: %d\n", Fat32VolumeBootSector->NumberOfFats);
187 TRACE("RootDirEntries: %d\n", Fat32VolumeBootSector->RootDirEntries);
188 TRACE("TotalSectors: %d\n", Fat32VolumeBootSector->TotalSectors);
189 TRACE("MediaDescriptor: 0x%x\n", Fat32VolumeBootSector->MediaDescriptor);
190 TRACE("SectorsPerFat: %d\n", Fat32VolumeBootSector->SectorsPerFat);
191 TRACE("SectorsPerTrack: %d\n", Fat32VolumeBootSector->SectorsPerTrack);
192 TRACE("NumberOfHeads: %d\n", Fat32VolumeBootSector->NumberOfHeads);
193 TRACE("HiddenSectors: %d\n", Fat32VolumeBootSector->HiddenSectors);
194 TRACE("TotalSectorsBig: %d\n", Fat32VolumeBootSector->TotalSectorsBig);
195 TRACE("SectorsPerFatBig: %d\n", Fat32VolumeBootSector->SectorsPerFatBig);
196 TRACE("ExtendedFlags: 0x%x\n", Fat32VolumeBootSector->ExtendedFlags);
197 TRACE("FileSystemVersion: 0x%x\n", Fat32VolumeBootSector->FileSystemVersion);
198 TRACE("RootDirStartCluster: %d\n", Fat32VolumeBootSector->RootDirStartCluster);
199 TRACE("FsInfo: %d\n", Fat32VolumeBootSector->FsInfo);
200 TRACE("BackupBootSector: %d\n", Fat32VolumeBootSector->BackupBootSector);
201 TRACE("Reserved: 0x%x\n", Fat32VolumeBootSector->Reserved);
202 TRACE("DriveNumber: 0x%x\n", Fat32VolumeBootSector->DriveNumber);
203 TRACE("Reserved1: 0x%x\n", Fat32VolumeBootSector->Reserved1);
204 TRACE("BootSignature: 0x%x\n", Fat32VolumeBootSector->BootSignature);
205 TRACE("VolumeSerialNumber: 0x%x\n", Fat32VolumeBootSector->VolumeSerialNumber);
206 TRACE("VolumeLabel: %c%c%c%c%c%c%c%c%c%c%c\n", Fat32VolumeBootSector->VolumeLabel[0], Fat32VolumeBootSector->VolumeLabel[1], Fat32VolumeBootSector->VolumeLabel[2], Fat32VolumeBootSector->VolumeLabel[3], Fat32VolumeBootSector->VolumeLabel[4], Fat32VolumeBootSector->VolumeLabel[5], Fat32VolumeBootSector->VolumeLabel[6], Fat32VolumeBootSector->VolumeLabel[7], Fat32VolumeBootSector->VolumeLabel[8], Fat32VolumeBootSector->VolumeLabel[9], Fat32VolumeBootSector->VolumeLabel[10]);
207 TRACE("FileSystemType: %c%c%c%c%c%c%c%c\n", Fat32VolumeBootSector->FileSystemType[0], Fat32VolumeBootSector->FileSystemType[1], Fat32VolumeBootSector->FileSystemType[2], Fat32VolumeBootSector->FileSystemType[3], Fat32VolumeBootSector->FileSystemType[4], Fat32VolumeBootSector->FileSystemType[5], Fat32VolumeBootSector->FileSystemType[6], Fat32VolumeBootSector->FileSystemType[7]);
208 TRACE("BootSectorMagic: 0x%x\n", Fat32VolumeBootSector->BootSectorMagic);
209 }
210 else
211 {
212 FatSwapFatBootSector(FatVolumeBootSector);
213 TRACE("sizeof(FAT_BOOTSECTOR) = 0x%x.\n", sizeof(FAT_BOOTSECTOR));
214
215 TRACE("JumpBoot: 0x%x 0x%x 0x%x\n", FatVolumeBootSector->JumpBoot[0], FatVolumeBootSector->JumpBoot[1], FatVolumeBootSector->JumpBoot[2]);
216 TRACE("OemName: %c%c%c%c%c%c%c%c\n", FatVolumeBootSector->OemName[0], FatVolumeBootSector->OemName[1], FatVolumeBootSector->OemName[2], FatVolumeBootSector->OemName[3], FatVolumeBootSector->OemName[4], FatVolumeBootSector->OemName[5], FatVolumeBootSector->OemName[6], FatVolumeBootSector->OemName[7]);
217 TRACE("BytesPerSector: %d\n", FatVolumeBootSector->BytesPerSector);
218 TRACE("SectorsPerCluster: %d\n", FatVolumeBootSector->SectorsPerCluster);
219 TRACE("ReservedSectors: %d\n", FatVolumeBootSector->ReservedSectors);
220 TRACE("NumberOfFats: %d\n", FatVolumeBootSector->NumberOfFats);
221 TRACE("RootDirEntries: %d\n", FatVolumeBootSector->RootDirEntries);
222 TRACE("TotalSectors: %d\n", FatVolumeBootSector->TotalSectors);
223 TRACE("MediaDescriptor: 0x%x\n", FatVolumeBootSector->MediaDescriptor);
224 TRACE("SectorsPerFat: %d\n", FatVolumeBootSector->SectorsPerFat);
225 TRACE("SectorsPerTrack: %d\n", FatVolumeBootSector->SectorsPerTrack);
226 TRACE("NumberOfHeads: %d\n", FatVolumeBootSector->NumberOfHeads);
227 TRACE("HiddenSectors: %d\n", FatVolumeBootSector->HiddenSectors);
228 TRACE("TotalSectorsBig: %d\n", FatVolumeBootSector->TotalSectorsBig);
229 TRACE("DriveNumber: 0x%x\n", FatVolumeBootSector->DriveNumber);
230 TRACE("Reserved1: 0x%x\n", FatVolumeBootSector->Reserved1);
231 TRACE("BootSignature: 0x%x\n", FatVolumeBootSector->BootSignature);
232 TRACE("VolumeSerialNumber: 0x%x\n", FatVolumeBootSector->VolumeSerialNumber);
233 TRACE("VolumeLabel: %c%c%c%c%c%c%c%c%c%c%c\n", FatVolumeBootSector->VolumeLabel[0], FatVolumeBootSector->VolumeLabel[1], FatVolumeBootSector->VolumeLabel[2], FatVolumeBootSector->VolumeLabel[3], FatVolumeBootSector->VolumeLabel[4], FatVolumeBootSector->VolumeLabel[5], FatVolumeBootSector->VolumeLabel[6], FatVolumeBootSector->VolumeLabel[7], FatVolumeBootSector->VolumeLabel[8], FatVolumeBootSector->VolumeLabel[9], FatVolumeBootSector->VolumeLabel[10]);
234 TRACE("FileSystemType: %c%c%c%c%c%c%c%c\n", FatVolumeBootSector->FileSystemType[0], FatVolumeBootSector->FileSystemType[1], FatVolumeBootSector->FileSystemType[2], FatVolumeBootSector->FileSystemType[3], FatVolumeBootSector->FileSystemType[4], FatVolumeBootSector->FileSystemType[5], FatVolumeBootSector->FileSystemType[6], FatVolumeBootSector->FileSystemType[7]);
235 TRACE("BootSectorMagic: 0x%x\n", FatVolumeBootSector->BootSectorMagic);
236 }
237
238 //
239 // Check the boot sector magic
240 //
241 if (! ISFATX(Volume->FatType) && FatVolumeBootSector->BootSectorMagic != 0xaa55)
242 {
243 sprintf(ErrMsg, "Invalid boot sector magic (expected 0xaa55 found 0x%x)",
244 FatVolumeBootSector->BootSectorMagic);
245 FileSystemError(ErrMsg);
246 return FALSE;
247 }
248
249 //
250 // Check the FAT cluster size
251 // We do not support clusters bigger than 64k
252 //
253 if ((ISFATX(Volume->FatType) && 64 * 1024 < FatXVolumeBootSector->SectorsPerCluster * 512) ||
254 (! ISFATX(Volume->FatType) && 64 * 1024 < FatVolumeBootSector->SectorsPerCluster * FatVolumeBootSector->BytesPerSector))
255 {
256 FileSystemError("This file system has cluster sizes bigger than 64k.\nFreeLoader does not support this.");
257 return FALSE;
258 }
259
260 //
261 // Get the sectors per FAT,
262 // root directory starting sector,
263 // and data sector start
264 //
265 if (ISFATX(Volume->FatType))
266 {
267 Volume->BytesPerSector = 512;
268 Volume->SectorsPerCluster = SWAPD(FatXVolumeBootSector->SectorsPerCluster);
269 Volume->FatSectorStart = (0x1000 / Volume->BytesPerSector);
270 Volume->ActiveFatSectorStart = Volume->FatSectorStart;
271 Volume->NumberOfFats = 1;
272 FatSize = (ULONG)(PartitionSectorCount / Volume->SectorsPerCluster *
273 (Volume->FatType == FATX16 ? 2 : 4));
274 Volume->SectorsPerFat = ROUND_UP(FatSize, 0x1000) / Volume->BytesPerSector;
275
276 Volume->RootDirSectorStart = Volume->FatSectorStart + Volume->NumberOfFats * Volume->SectorsPerFat;
277 Volume->RootDirSectors = FatXVolumeBootSector->SectorsPerCluster;
278
279 Volume->DataSectorStart = Volume->RootDirSectorStart + Volume->RootDirSectors;
280 }
281 else if (Volume->FatType != FAT32)
282 {
283 Volume->BytesPerSector = FatVolumeBootSector->BytesPerSector;
284 Volume->SectorsPerCluster = FatVolumeBootSector->SectorsPerCluster;
285 Volume->FatSectorStart = FatVolumeBootSector->ReservedSectors;
286 Volume->ActiveFatSectorStart = Volume->FatSectorStart;
287 Volume->NumberOfFats = FatVolumeBootSector->NumberOfFats;
288 Volume->SectorsPerFat = FatVolumeBootSector->SectorsPerFat;
289
290 Volume->RootDirSectorStart = Volume->FatSectorStart + Volume->NumberOfFats * Volume->SectorsPerFat;
291 Volume->RootDirSectors = ((FatVolumeBootSector->RootDirEntries * 32) + (Volume->BytesPerSector - 1)) / Volume->BytesPerSector;
292
293 Volume->DataSectorStart = Volume->RootDirSectorStart + Volume->RootDirSectors;
294 }
295 else
296 {
297 Volume->BytesPerSector = Fat32VolumeBootSector->BytesPerSector;
298 Volume->SectorsPerCluster = Fat32VolumeBootSector->SectorsPerCluster;
299 Volume->FatSectorStart = Fat32VolumeBootSector->ReservedSectors;
300 Volume->ActiveFatSectorStart = Volume->FatSectorStart +
301 ((Fat32VolumeBootSector->ExtendedFlags & 0x80) ? ((Fat32VolumeBootSector->ExtendedFlags & 0x0f) * Fat32VolumeBootSector->SectorsPerFatBig) : 0);
302 Volume->NumberOfFats = Fat32VolumeBootSector->NumberOfFats;
303 Volume->SectorsPerFat = Fat32VolumeBootSector->SectorsPerFatBig;
304
305 Volume->RootDirStartCluster = Fat32VolumeBootSector->RootDirStartCluster;
306 Volume->DataSectorStart = Volume->FatSectorStart + Volume->NumberOfFats * Volume->SectorsPerFat;
307
308 //
309 // Check version
310 // we only work with version 0
311 //
312 if (Fat32VolumeBootSector->FileSystemVersion != 0)
313 {
314 FileSystemError("FreeLoader is too old to work with this FAT32 filesystem.\nPlease update FreeLoader.");
315 return FALSE;
316 }
317 }
318
319 return TRUE;
320 }
321
322 ULONG FatDetermineFatType(PFAT_BOOTSECTOR FatBootSector, ULONGLONG PartitionSectorCount)
323 {
324 ULONG RootDirSectors;
325 ULONG DataSectorCount;
326 ULONG SectorsPerFat;
327 ULONG TotalSectors;
328 ULONG CountOfClusters;
329 PFAT32_BOOTSECTOR Fat32BootSector = (PFAT32_BOOTSECTOR)FatBootSector;
330 PFATX_BOOTSECTOR FatXBootSector = (PFATX_BOOTSECTOR)FatBootSector;
331
332 if (0 == strncmp(FatXBootSector->FileSystemType, "FATX", 4))
333 {
334 CountOfClusters = (ULONG)(PartitionSectorCount / FatXBootSector->SectorsPerCluster);
335 if (CountOfClusters < 65525)
336 {
337 /* Volume is FATX16 */
338 return FATX16;
339 }
340 else
341 {
342 /* Volume is FAT32 */
343 return FATX32;
344 }
345 }
346 else
347 {
348 RootDirSectors = ((SWAPW(FatBootSector->RootDirEntries) * 32) + (SWAPW(FatBootSector->BytesPerSector) - 1)) / SWAPW(FatBootSector->BytesPerSector);
349 SectorsPerFat = SWAPW(FatBootSector->SectorsPerFat) ? SWAPW(FatBootSector->SectorsPerFat) : SWAPD(Fat32BootSector->SectorsPerFatBig);
350 TotalSectors = SWAPW(FatBootSector->TotalSectors) ? SWAPW(FatBootSector->TotalSectors) : SWAPD(FatBootSector->TotalSectorsBig);
351 DataSectorCount = TotalSectors - (SWAPW(FatBootSector->ReservedSectors) + (FatBootSector->NumberOfFats * SectorsPerFat) + RootDirSectors);
352
353 //mjl
354 if (FatBootSector->SectorsPerCluster == 0)
355 CountOfClusters = 0;
356 else
357 CountOfClusters = DataSectorCount / FatBootSector->SectorsPerCluster;
358
359 if (CountOfClusters < 4085)
360 {
361 /* Volume is FAT12 */
362 return FAT12;
363 }
364 else if (CountOfClusters < 65525)
365 {
366 /* Volume is FAT16 */
367 return FAT16;
368 }
369 else
370 {
371 /* Volume is FAT32 */
372 return FAT32;
373 }
374 }
375 }
376
377 typedef struct _DIRECTORY_BUFFER
378 {
379 LIST_ENTRY Link;
380 PVOID Volume;
381 ULONG DirectoryStartCluster;
382 ULONG DirectorySize;
383 UCHAR Data[];
384 } DIRECTORY_BUFFER, *PDIRECTORY_BUFFER;
385
386 LIST_ENTRY DirectoryBufferListHead = {&DirectoryBufferListHead, &DirectoryBufferListHead};
387
388 PVOID FatBufferDirectory(PFAT_VOLUME_INFO Volume, ULONG DirectoryStartCluster, ULONG *DirectorySize, BOOLEAN RootDirectory)
389 {
390 PDIRECTORY_BUFFER DirectoryBuffer;
391 PLIST_ENTRY Entry;
392
393 TRACE("FatBufferDirectory() DirectoryStartCluster = %d RootDirectory = %s\n", DirectoryStartCluster, (RootDirectory ? "TRUE" : "FALSE"));
394
395 /*
396 * For FAT32, the root directory is nothing special. We can treat it the same
397 * as a subdirectory.
398 */
399 if (RootDirectory && Volume->FatType == FAT32)
400 {
401 DirectoryStartCluster = Volume->RootDirStartCluster;
402 RootDirectory = FALSE;
403 }
404
405 /* Search the list for a match */
406 for (Entry = DirectoryBufferListHead.Flink;
407 Entry != &DirectoryBufferListHead;
408 Entry = Entry->Flink)
409 {
410 DirectoryBuffer = CONTAINING_RECORD(Entry, DIRECTORY_BUFFER, Link);
411
412 /* Check if it matches */
413 if ((DirectoryBuffer->Volume == Volume) &&
414 (DirectoryBuffer->DirectoryStartCluster == DirectoryStartCluster))
415 {
416 TRACE("Found cached buffer\n");
417 *DirectorySize = DirectoryBuffer->DirectorySize;
418 return DirectoryBuffer->Data;
419 }
420 }
421
422 //
423 // Calculate the size of the directory
424 //
425 if (RootDirectory)
426 {
427 *DirectorySize = Volume->RootDirSectors * Volume->BytesPerSector;
428 }
429 else
430 {
431 *DirectorySize = FatCountClustersInChain(Volume, DirectoryStartCluster) * Volume->SectorsPerCluster * Volume->BytesPerSector;
432 }
433
434 //
435 // Attempt to allocate memory for directory buffer
436 //
437 TRACE("Trying to allocate (DirectorySize) %d bytes.\n", *DirectorySize);
438 DirectoryBuffer = FrLdrTempAlloc(*DirectorySize + sizeof(DIRECTORY_BUFFER),
439 TAG_FAT_BUFFER);
440
441 if (DirectoryBuffer == NULL)
442 {
443 return NULL;
444 }
445
446 //
447 // Now read directory contents into DirectoryBuffer
448 //
449 if (RootDirectory)
450 {
451 if (!FatReadVolumeSectors(Volume, Volume->RootDirSectorStart, Volume->RootDirSectors, DirectoryBuffer->Data))
452 {
453 FrLdrTempFree(DirectoryBuffer, TAG_FAT_BUFFER);
454 return NULL;
455 }
456 }
457 else
458 {
459 if (!FatReadClusterChain(Volume, DirectoryStartCluster, 0xFFFFFFFF, DirectoryBuffer->Data))
460 {
461 FrLdrTempFree(DirectoryBuffer, TAG_FAT_BUFFER);
462 return NULL;
463 }
464 }
465
466 /* Enqueue it in the list */
467 DirectoryBuffer->Volume = Volume;
468 DirectoryBuffer->DirectoryStartCluster = DirectoryStartCluster;
469 DirectoryBuffer->DirectorySize = *DirectorySize;
470 InsertTailList(&DirectoryBufferListHead, &DirectoryBuffer->Link);
471
472 return DirectoryBuffer->Data;
473 }
474
475 BOOLEAN FatSearchDirectoryBufferForFile(PFAT_VOLUME_INFO Volume, PVOID DirectoryBuffer, ULONG DirectorySize, PCHAR FileName, PFAT_FILE_INFO FatFileInfoPointer)
476 {
477 ULONG EntryCount;
478 ULONG CurrentEntry;
479 CHAR LfnNameBuffer[265];
480 CHAR ShortNameBuffer[20];
481 ULONG StartCluster;
482 DIRENTRY OurDirEntry;
483 LFN_DIRENTRY OurLfnDirEntry;
484 PDIRENTRY DirEntry = &OurDirEntry;
485 PLFN_DIRENTRY LfnDirEntry = &OurLfnDirEntry;
486
487 EntryCount = DirectorySize / sizeof(DIRENTRY);
488
489 TRACE("FatSearchDirectoryBufferForFile() DirectoryBuffer = 0x%x EntryCount = %d FileName = %s\n", DirectoryBuffer, EntryCount, FileName);
490
491 memset(ShortNameBuffer, 0, 13 * sizeof(CHAR));
492 memset(LfnNameBuffer, 0, 261 * sizeof(CHAR));
493
494 for (CurrentEntry=0; CurrentEntry<EntryCount; CurrentEntry++, DirectoryBuffer = ((PDIRENTRY)DirectoryBuffer)+1)
495 {
496 OurLfnDirEntry = *((PLFN_DIRENTRY) DirectoryBuffer);
497 FatSwapLFNDirEntry(LfnDirEntry);
498 OurDirEntry = *((PDIRENTRY) DirectoryBuffer);
499 FatSwapDirEntry(DirEntry);
500
501 //TRACE("Dumping directory entry %d:\n", CurrentEntry);
502 //DbgDumpBuffer(DPRINT_FILESYSTEM, DirEntry, sizeof(DIRENTRY));
503
504 //
505 // Check if this is the last file in the directory
506 // If DirEntry[0] == 0x00 then that means all the
507 // entries after this one are unused. If this is the
508 // last entry then we didn't find the file in this directory.
509 //
510 if (DirEntry->FileName[0] == '\0')
511 {
512 return FALSE;
513 }
514
515 //
516 // Check if this is a deleted entry or not
517 //
518 if (DirEntry->FileName[0] == '\xE5')
519 {
520 memset(ShortNameBuffer, 0, 13 * sizeof(CHAR));
521 memset(LfnNameBuffer, 0, 261 * sizeof(CHAR));
522 continue;
523 }
524
525 //
526 // Check if this is a LFN entry
527 // If so it needs special handling
528 //
529 if (DirEntry->Attr == ATTR_LONG_NAME)
530 {
531 //
532 // Check to see if this is a deleted LFN entry, if so continue
533 //
534 if (LfnDirEntry->SequenceNumber & 0x80)
535 {
536 continue;
537 }
538
539 //
540 // Mask off high two bits of sequence number
541 // and make the sequence number zero-based
542 //
543 LfnDirEntry->SequenceNumber &= 0x3F;
544 LfnDirEntry->SequenceNumber--;
545
546 //
547 // Get all 13 LFN entry characters
548 //
549 if (LfnDirEntry->Name0_4[0] != 0xFFFF)
550 {
551 LfnNameBuffer[0 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[0];
552 }
553 if (LfnDirEntry->Name0_4[1] != 0xFFFF)
554 {
555 LfnNameBuffer[1 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[1];
556 }
557 if (LfnDirEntry->Name0_4[2] != 0xFFFF)
558 {
559 LfnNameBuffer[2 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[2];
560 }
561 if (LfnDirEntry->Name0_4[3] != 0xFFFF)
562 {
563 LfnNameBuffer[3 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[3];
564 }
565 if (LfnDirEntry->Name0_4[4] != 0xFFFF)
566 {
567 LfnNameBuffer[4 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[4];
568 }
569 if (LfnDirEntry->Name5_10[0] != 0xFFFF)
570 {
571 LfnNameBuffer[5 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[0];
572 }
573 if (LfnDirEntry->Name5_10[1] != 0xFFFF)
574 {
575 LfnNameBuffer[6 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[1];
576 }
577 if (LfnDirEntry->Name5_10[2] != 0xFFFF)
578 {
579 LfnNameBuffer[7 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[2];
580 }
581 if (LfnDirEntry->Name5_10[3] != 0xFFFF)
582 {
583 LfnNameBuffer[8 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[3];
584 }
585 if (LfnDirEntry->Name5_10[4] != 0xFFFF)
586 {
587 LfnNameBuffer[9 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[4];
588 }
589 if (LfnDirEntry->Name5_10[5] != 0xFFFF)
590 {
591 LfnNameBuffer[10 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[5];
592 }
593 if (LfnDirEntry->Name11_12[0] != 0xFFFF)
594 {
595 LfnNameBuffer[11 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name11_12[0];
596 }
597 if (LfnDirEntry->Name11_12[1] != 0xFFFF)
598 {
599 LfnNameBuffer[12 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name11_12[1];
600 }
601
602 //TRACE("Dumping long name buffer:\n");
603 //DbgDumpBuffer(DPRINT_FILESYSTEM, LfnNameBuffer, 260);
604
605 continue;
606 }
607
608 //
609 // Check for the volume label attribute
610 // and skip over this entry if found
611 //
612 if (DirEntry->Attr & ATTR_VOLUMENAME)
613 {
614 memset(ShortNameBuffer, 0, 13 * sizeof(UCHAR));
615 memset(LfnNameBuffer, 0, 261 * sizeof(UCHAR));
616 continue;
617 }
618
619 //
620 // If we get here then we've found a short file name
621 // entry and LfnNameBuffer contains the long file
622 // name or zeroes. All we have to do now is see if the
623 // file name matches either the short or long file name
624 // and fill in the FAT_FILE_INFO structure if it does
625 // or zero our buffers and continue looking.
626 //
627
628 //
629 // Get short file name
630 //
631 FatParseShortFileName(ShortNameBuffer, DirEntry);
632
633 //TRACE("Entry: %d LFN = %s\n", CurrentEntry, LfnNameBuffer);
634 //TRACE("Entry: %d DOS name = %s\n", CurrentEntry, ShortNameBuffer);
635
636 //
637 // See if the file name matches either the short or long name
638 //
639 if (((strlen(FileName) == strlen(LfnNameBuffer)) && (_stricmp(FileName, LfnNameBuffer) == 0)) ||
640 ((strlen(FileName) == strlen(ShortNameBuffer)) && (_stricmp(FileName, ShortNameBuffer) == 0))) {
641 //
642 // We found the entry, now fill in the FAT_FILE_INFO struct
643 //
644 FatFileInfoPointer->Attributes = DirEntry->Attr;
645 FatFileInfoPointer->FileSize = DirEntry->Size;
646 FatFileInfoPointer->FilePointer = 0;
647
648 TRACE("MSDOS Directory Entry:\n");
649 TRACE("FileName[11] = %c%c%c%c%c%c%c%c%c%c%c\n", DirEntry->FileName[0], DirEntry->FileName[1], DirEntry->FileName[2], DirEntry->FileName[3], DirEntry->FileName[4], DirEntry->FileName[5], DirEntry->FileName[6], DirEntry->FileName[7], DirEntry->FileName[8], DirEntry->FileName[9], DirEntry->FileName[10]);
650 TRACE("Attr = 0x%x\n", DirEntry->Attr);
651 TRACE("ReservedNT = 0x%x\n", DirEntry->ReservedNT);
652 TRACE("TimeInTenths = %d\n", DirEntry->TimeInTenths);
653 TRACE("CreateTime = %d\n", DirEntry->CreateTime);
654 TRACE("CreateDate = %d\n", DirEntry->CreateDate);
655 TRACE("LastAccessDate = %d\n", DirEntry->LastAccessDate);
656 TRACE("ClusterHigh = 0x%x\n", DirEntry->ClusterHigh);
657 TRACE("Time = %d\n", DirEntry->Time);
658 TRACE("Date = %d\n", DirEntry->Date);
659 TRACE("ClusterLow = 0x%x\n", DirEntry->ClusterLow);
660 TRACE("Size = %d\n", DirEntry->Size);
661
662 //
663 // Get the cluster chain
664 //
665 StartCluster = ((ULONG)DirEntry->ClusterHigh << 16) + DirEntry->ClusterLow;
666 TRACE("StartCluster = 0x%x\n", StartCluster);
667 FatFileInfoPointer->FileFatChain = FatGetClusterChainArray(Volume, StartCluster);
668
669 //
670 // See if memory allocation failed
671 //
672 if (FatFileInfoPointer->FileFatChain == NULL)
673 {
674 return FALSE;
675 }
676
677 return TRUE;
678 }
679
680 //
681 // Nope, no match - zero buffers and continue looking
682 //
683 memset(ShortNameBuffer, 0, 13 * sizeof(UCHAR));
684 memset(LfnNameBuffer, 0, 261 * sizeof(UCHAR));
685 continue;
686 }
687
688 return FALSE;
689 }
690
691 static BOOLEAN FatXSearchDirectoryBufferForFile(PFAT_VOLUME_INFO Volume, PVOID DirectoryBuffer, ULONG DirectorySize, PCHAR FileName, PFAT_FILE_INFO FatFileInfoPointer)
692 {
693 ULONG EntryCount;
694 ULONG CurrentEntry;
695 SIZE_T FileNameLen;
696 FATX_DIRENTRY OurDirEntry;
697 PFATX_DIRENTRY DirEntry = &OurDirEntry;
698
699 EntryCount = DirectorySize / sizeof(FATX_DIRENTRY);
700
701 TRACE("FatXSearchDirectoryBufferForFile() DirectoryBuffer = 0x%x EntryCount = %d FileName = %s\n", DirectoryBuffer, EntryCount, FileName);
702
703 FileNameLen = strlen(FileName);
704
705 for (CurrentEntry = 0; CurrentEntry < EntryCount; CurrentEntry++, DirectoryBuffer = ((PFATX_DIRENTRY)DirectoryBuffer)+1)
706 {
707 OurDirEntry = *(PFATX_DIRENTRY) DirectoryBuffer;
708 FatSwapFatXDirEntry(&OurDirEntry);
709 if (0xff == DirEntry->FileNameSize)
710 {
711 break;
712 }
713 if (0xe5 == DirEntry->FileNameSize)
714 {
715 continue;
716 }
717 if (FileNameLen == DirEntry->FileNameSize &&
718 0 == _strnicmp(FileName, DirEntry->FileName, FileNameLen))
719 {
720 /*
721 * We found the entry, now fill in the FAT_FILE_INFO struct
722 */
723 FatFileInfoPointer->Attributes = DirEntry->Attr;
724 FatFileInfoPointer->FileSize = DirEntry->Size;
725 FatFileInfoPointer->FilePointer = 0;
726
727 TRACE("FATX Directory Entry:\n");
728 TRACE("FileNameSize = %d\n", DirEntry->FileNameSize);
729 TRACE("Attr = 0x%x\n", DirEntry->Attr);
730 TRACE("StartCluster = 0x%x\n", DirEntry->StartCluster);
731 TRACE("Size = %d\n", DirEntry->Size);
732 TRACE("Time = %d\n", DirEntry->Time);
733 TRACE("Date = %d\n", DirEntry->Date);
734 TRACE("CreateTime = %d\n", DirEntry->CreateTime);
735 TRACE("CreateDate = %d\n", DirEntry->CreateDate);
736 TRACE("LastAccessTime = %d\n", DirEntry->LastAccessTime);
737 TRACE("LastAccessDate = %d\n", DirEntry->LastAccessDate);
738
739 /*
740 * Get the cluster chain
741 */
742 FatFileInfoPointer->FileFatChain = FatGetClusterChainArray(Volume, DirEntry->StartCluster);
743
744 /*
745 * See if memory allocation failed
746 */
747 if (NULL == FatFileInfoPointer->FileFatChain)
748 {
749 return FALSE;
750 }
751
752 return TRUE;
753 }
754 }
755
756 return FALSE;
757 }
758
759 /*
760 * FatLookupFile()
761 * This function searches the file system for the
762 * specified filename and fills in an FAT_FILE_INFO structure
763 * with info describing the file, etc. returns ARC error code
764 */
765 ARC_STATUS FatLookupFile(PFAT_VOLUME_INFO Volume, PCSTR FileName, ULONG DeviceId, PFAT_FILE_INFO FatFileInfoPointer)
766 {
767 UINT32 i;
768 ULONG NumberOfPathParts;
769 CHAR PathPart[261];
770 PVOID DirectoryBuffer;
771 ULONG DirectoryStartCluster = 0;
772 ULONG DirectorySize;
773 FAT_FILE_INFO FatFileInfo;
774
775 TRACE("FatLookupFile() FileName = %s\n", FileName);
776
777 memset(FatFileInfoPointer, 0, sizeof(FAT_FILE_INFO));
778
779 //
780 // Figure out how many sub-directories we are nested in
781 //
782 NumberOfPathParts = FsGetNumPathParts(FileName);
783
784 //
785 // Loop once for each part
786 //
787 for (i=0; i<NumberOfPathParts; i++)
788 {
789 //
790 // Get first path part
791 //
792 FsGetFirstNameFromPath(PathPart, FileName);
793
794 //
795 // Advance to the next part of the path
796 //
797 for (; (*FileName != '\\') && (*FileName != '/') && (*FileName != '\0'); FileName++)
798 {
799 }
800 FileName++;
801
802 //
803 // Buffer the directory contents
804 //
805 DirectoryBuffer = FatBufferDirectory(Volume, DirectoryStartCluster, &DirectorySize, (i == 0) );
806 if (DirectoryBuffer == NULL)
807 {
808 return ENOMEM;
809 }
810
811 //
812 // Search for file name in directory
813 //
814 if (ISFATX(Volume->FatType))
815 {
816 if (!FatXSearchDirectoryBufferForFile(Volume, DirectoryBuffer, DirectorySize, PathPart, &FatFileInfo))
817 {
818 return ENOENT;
819 }
820 }
821 else
822 {
823 if (!FatSearchDirectoryBufferForFile(Volume, DirectoryBuffer, DirectorySize, PathPart, &FatFileInfo))
824 {
825 return ENOENT;
826 }
827 }
828
829 //
830 // If we have another sub-directory to go then
831 // grab the start cluster and free the fat chain array
832 //
833 if ((i+1) < NumberOfPathParts)
834 {
835 //
836 // Check if current entry is a directory
837 //
838 if (!(FatFileInfo.Attributes & ATTR_DIRECTORY))
839 {
840 FrLdrTempFree(FatFileInfo.FileFatChain, TAG_FAT_CHAIN);
841 return ENOTDIR;
842 }
843 DirectoryStartCluster = FatFileInfo.FileFatChain[0];
844 FrLdrTempFree(FatFileInfo.FileFatChain, TAG_FAT_CHAIN);
845 FatFileInfo.FileFatChain = NULL;
846 }
847 }
848
849 memcpy(FatFileInfoPointer, &FatFileInfo, sizeof(FAT_FILE_INFO));
850
851 return ESUCCESS;
852 }
853
854 /*
855 * FatParseFileName()
856 * This function parses a directory entry name which
857 * is in the form of "FILE EXT" and puts it in Buffer
858 * in the form of "file.ext"
859 */
860 void FatParseShortFileName(PCHAR Buffer, PDIRENTRY DirEntry)
861 {
862 ULONG Idx;
863
864 Idx = 0;
865 RtlZeroMemory(Buffer, 13);
866
867 //
868 // Fixup first character
869 //
870 if (DirEntry->FileName[0] == 0x05)
871 {
872 DirEntry->FileName[0] = 0xE5;
873 }
874
875 //
876 // Get the file name
877 //
878 while (Idx < 8)
879 {
880 if (DirEntry->FileName[Idx] == ' ')
881 {
882 break;
883 }
884
885 Buffer[Idx] = DirEntry->FileName[Idx];
886 Idx++;
887 }
888
889 //
890 // Get extension
891 //
892 if ((DirEntry->FileName[8] != ' '))
893 {
894 Buffer[Idx++] = '.';
895 Buffer[Idx++] = (DirEntry->FileName[8] == ' ') ? '\0' : DirEntry->FileName[8];
896 Buffer[Idx++] = (DirEntry->FileName[9] == ' ') ? '\0' : DirEntry->FileName[9];
897 Buffer[Idx++] = (DirEntry->FileName[10] == ' ') ? '\0' : DirEntry->FileName[10];
898 }
899
900 //TRACE("FatParseShortFileName() ShortName = %s\n", Buffer);
901 }
902
903 /*
904 * FatGetFatEntry()
905 * returns the Fat entry for a given cluster number
906 */
907 BOOLEAN FatGetFatEntry(PFAT_VOLUME_INFO Volume, ULONG Cluster, ULONG* ClusterPointer)
908 {
909 ULONG fat = 0;
910 UINT32 FatOffset;
911 UINT32 ThisFatSecNum;
912 UINT32 ThisFatEntOffset;
913 ULONG SectorCount;
914 PUCHAR ReadBuffer;
915 BOOLEAN Success = TRUE;
916
917 //TRACE("FatGetFatEntry() Retrieving FAT entry for cluster %d.\n", Cluster);
918
919 // We need a buffer for 2 sectors
920 ReadBuffer = FrLdrTempAlloc(2 * Volume->BytesPerSector, TAG_FAT_BUFFER);
921 if (!ReadBuffer)
922 {
923 return FALSE;
924 }
925
926 switch(Volume->FatType)
927 {
928 case FAT12:
929
930 FatOffset = Cluster + (Cluster / 2);
931 ThisFatSecNum = Volume->ActiveFatSectorStart + (FatOffset / Volume->BytesPerSector);
932 ThisFatEntOffset = (FatOffset % Volume->BytesPerSector);
933
934 TRACE("FatOffset: %d\n", FatOffset);
935 TRACE("ThisFatSecNum: %d\n", ThisFatSecNum);
936 TRACE("ThisFatEntOffset: %d\n", ThisFatEntOffset);
937
938 if (ThisFatEntOffset == (Volume->BytesPerSector - 1))
939 {
940 SectorCount = 2;
941 }
942 else
943 {
944 SectorCount = 1;
945 }
946
947 if (!FatReadVolumeSectors(Volume, ThisFatSecNum, SectorCount, ReadBuffer))
948 {
949 Success = FALSE;
950 break;
951 }
952
953 fat = *((USHORT *) (ReadBuffer + ThisFatEntOffset));
954 fat = SWAPW(fat);
955 if (Cluster & 0x0001)
956 fat = fat >> 4; /* Cluster number is ODD */
957 else
958 fat = fat & 0x0FFF; /* Cluster number is EVEN */
959
960 break;
961
962 case FAT16:
963 case FATX16:
964
965 FatOffset = (Cluster * 2);
966 ThisFatSecNum = Volume->ActiveFatSectorStart + (FatOffset / Volume->BytesPerSector);
967 ThisFatEntOffset = (FatOffset % Volume->BytesPerSector);
968
969 if (!FatReadVolumeSectors(Volume, ThisFatSecNum, 1, ReadBuffer))
970 {
971 Success = FALSE;
972 break;
973 }
974
975 fat = *((USHORT *) (ReadBuffer + ThisFatEntOffset));
976 fat = SWAPW(fat);
977
978 break;
979
980 case FAT32:
981 case FATX32:
982
983 FatOffset = (Cluster * 4);
984 ThisFatSecNum = Volume->ActiveFatSectorStart + (FatOffset / Volume->BytesPerSector);
985 ThisFatEntOffset = (FatOffset % Volume->BytesPerSector);
986
987 if (!FatReadVolumeSectors(Volume, ThisFatSecNum, 1, ReadBuffer))
988 {
989 return FALSE;
990 }
991
992 // Get the fat entry
993 fat = (*((ULONG *) (ReadBuffer + ThisFatEntOffset))) & 0x0FFFFFFF;
994 fat = SWAPD(fat);
995
996 break;
997
998 default:
999 ERR("Unknown FAT type %d\n", Volume->FatType);
1000 Success = FALSE;
1001 break;
1002 }
1003
1004 //TRACE("FAT entry is 0x%x.\n", fat);
1005
1006 FrLdrTempFree(ReadBuffer, TAG_FAT_BUFFER);
1007
1008 *ClusterPointer = fat;
1009
1010 return Success;
1011 }
1012
1013 ULONG FatCountClustersInChain(PFAT_VOLUME_INFO Volume, ULONG StartCluster)
1014 {
1015 ULONG ClusterCount = 0;
1016
1017 TRACE("FatCountClustersInChain() StartCluster = %d\n", StartCluster);
1018
1019 while (1)
1020 {
1021 //
1022 // If end of chain then break out of our cluster counting loop
1023 //
1024 if (((Volume->FatType == FAT12) && (StartCluster >= 0xff8)) ||
1025 ((Volume->FatType == FAT16 || Volume->FatType == FATX16) && (StartCluster >= 0xfff8)) ||
1026 ((Volume->FatType == FAT32 || Volume->FatType == FATX32) && (StartCluster >= 0x0ffffff8)))
1027 {
1028 break;
1029 }
1030
1031 //
1032 // Increment count
1033 //
1034 ClusterCount++;
1035
1036 //
1037 // Get next cluster
1038 //
1039 if (!FatGetFatEntry(Volume, StartCluster, &StartCluster))
1040 {
1041 return 0;
1042 }
1043 }
1044
1045 TRACE("FatCountClustersInChain() ClusterCount = %d\n", ClusterCount);
1046
1047 return ClusterCount;
1048 }
1049
1050 ULONG* FatGetClusterChainArray(PFAT_VOLUME_INFO Volume, ULONG StartCluster)
1051 {
1052 ULONG ClusterCount;
1053 ULONG ArraySize;
1054 ULONG* ArrayPointer;
1055 ULONG Idx;
1056
1057 TRACE("FatGetClusterChainArray() StartCluster = %d\n", StartCluster);
1058
1059 ClusterCount = FatCountClustersInChain(Volume, StartCluster) + 1; // Lets get the 0x0ffffff8 on the end of the array
1060 ArraySize = ClusterCount * sizeof(ULONG);
1061
1062 //
1063 // Allocate array memory
1064 //
1065 ArrayPointer = FrLdrTempAlloc(ArraySize, TAG_FAT_CHAIN);
1066
1067 if (ArrayPointer == NULL)
1068 {
1069 return NULL;
1070 }
1071
1072 //
1073 // Loop through and set array values
1074 //
1075 for (Idx=0; Idx<ClusterCount; Idx++)
1076 {
1077 //
1078 // Set current cluster
1079 //
1080 ArrayPointer[Idx] = StartCluster;
1081
1082 //
1083 // Don't try to get next cluster for last cluster
1084 //
1085 if (((Volume->FatType == FAT12) && (StartCluster >= 0xff8)) ||
1086 ((Volume->FatType == FAT16 || Volume->FatType == FATX16) && (StartCluster >= 0xfff8)) ||
1087 ((Volume->FatType == FAT32 || Volume->FatType == FATX32) && (StartCluster >= 0x0ffffff8)))
1088 {
1089 Idx++;
1090 break;
1091 }
1092
1093 //
1094 // Get next cluster
1095 //
1096 if (!FatGetFatEntry(Volume, StartCluster, &StartCluster))
1097 {
1098 FrLdrTempFree(ArrayPointer, TAG_FAT_CHAIN);
1099 return NULL;
1100 }
1101 }
1102
1103 return ArrayPointer;
1104 }
1105
1106 /*
1107 * FatReadClusterChain()
1108 * Reads the specified clusters into memory
1109 */
1110 BOOLEAN FatReadClusterChain(PFAT_VOLUME_INFO Volume, ULONG StartClusterNumber, ULONG NumberOfClusters, PVOID Buffer)
1111 {
1112 ULONG ClusterStartSector;
1113
1114 TRACE("FatReadClusterChain() StartClusterNumber = %d NumberOfClusters = %d Buffer = 0x%x\n", StartClusterNumber, NumberOfClusters, Buffer);
1115
1116 while (NumberOfClusters > 0)
1117 {
1118
1119 //TRACE("FatReadClusterChain() StartClusterNumber = %d NumberOfClusters = %d Buffer = 0x%x\n", StartClusterNumber, NumberOfClusters, Buffer);
1120 //
1121 // Calculate starting sector for cluster
1122 //
1123 ClusterStartSector = ((StartClusterNumber - 2) * Volume->SectorsPerCluster) + Volume->DataSectorStart;
1124
1125 //
1126 // Read cluster into memory
1127 //
1128 if (!FatReadVolumeSectors(Volume, ClusterStartSector, Volume->SectorsPerCluster, Buffer))
1129 {
1130 return FALSE;
1131 }
1132
1133 //
1134 // Decrement count of clusters left to read
1135 //
1136 NumberOfClusters--;
1137
1138 //
1139 // Increment buffer address by cluster size
1140 //
1141 Buffer = (PVOID)((ULONG_PTR)Buffer + (Volume->SectorsPerCluster * Volume->BytesPerSector));
1142
1143 //
1144 // Get next cluster
1145 //
1146 if (!FatGetFatEntry(Volume, StartClusterNumber, &StartClusterNumber))
1147 {
1148 return FALSE;
1149 }
1150
1151 //
1152 // If end of chain then break out of our cluster reading loop
1153 //
1154 if (((Volume->FatType == FAT12) && (StartClusterNumber >= 0xff8)) ||
1155 ((Volume->FatType == FAT16 || Volume->FatType == FATX16) && (StartClusterNumber >= 0xfff8)) ||
1156 ((Volume->FatType == FAT32 || Volume->FatType == FATX32) && (StartClusterNumber >= 0x0ffffff8)))
1157 {
1158 break;
1159 }
1160 }
1161
1162 return TRUE;
1163 }
1164
1165 /*
1166 * FatReadPartialCluster()
1167 * Reads part of a cluster into memory
1168 */
1169 BOOLEAN FatReadPartialCluster(PFAT_VOLUME_INFO Volume, ULONG ClusterNumber, ULONG StartingOffset, ULONG Length, PVOID Buffer)
1170 {
1171 ULONG ClusterStartSector;
1172 ULONG SectorOffset, ReadSize, SectorCount;
1173 PUCHAR ReadBuffer;
1174 BOOLEAN Success = FALSE;
1175
1176 //TRACE("FatReadPartialCluster() ClusterNumber = %d StartingOffset = %d Length = %d Buffer = 0x%x\n", ClusterNumber, StartingOffset, Length, Buffer);
1177
1178 ClusterStartSector = ((ClusterNumber - 2) * Volume->SectorsPerCluster) + Volume->DataSectorStart;
1179
1180 // This is the offset of the data in sectors
1181 SectorOffset = (StartingOffset / Volume->BytesPerSector);
1182 StartingOffset %= Volume->BytesPerSector;
1183
1184 // Calculate how many sectors we need to read
1185 SectorCount = (StartingOffset + Length + Volume->BytesPerSector - 1) / Volume->BytesPerSector;
1186
1187 // Calculate rounded up read size
1188 ReadSize = SectorCount * Volume->BytesPerSector;
1189
1190 ReadBuffer = FrLdrTempAlloc(ReadSize, TAG_FAT_BUFFER);
1191 if (!ReadBuffer)
1192 {
1193 return FALSE;
1194 }
1195
1196 if (FatReadVolumeSectors(Volume, ClusterStartSector + SectorOffset, SectorCount, ReadBuffer))
1197 {
1198 memcpy(Buffer, ReadBuffer + StartingOffset, Length);
1199 Success = TRUE;
1200 }
1201
1202 FrLdrTempFree(ReadBuffer, TAG_FAT_BUFFER);
1203
1204 return Success;
1205 }
1206
1207 /*
1208 * FatReadFile()
1209 * Reads BytesToRead from open file and
1210 * returns the number of bytes read in BytesRead
1211 */
1212 BOOLEAN FatReadFile(PFAT_FILE_INFO FatFileInfo, ULONG BytesToRead, ULONG* BytesRead, PVOID Buffer)
1213 {
1214 PFAT_VOLUME_INFO Volume = FatFileInfo->Volume;
1215 ULONG ClusterNumber;
1216 ULONG OffsetInCluster;
1217 ULONG LengthInCluster;
1218 ULONG NumberOfClusters;
1219 ULONG BytesPerCluster;
1220
1221 TRACE("FatReadFile() BytesToRead = %d Buffer = 0x%x\n", BytesToRead, Buffer);
1222
1223 if (BytesRead != NULL)
1224 {
1225 *BytesRead = 0;
1226 }
1227
1228 //
1229 // If they are trying to read past the
1230 // end of the file then return success
1231 // with BytesRead == 0
1232 //
1233 if (FatFileInfo->FilePointer >= FatFileInfo->FileSize)
1234 {
1235 return TRUE;
1236 }
1237
1238 //
1239 // If they are trying to read more than there is to read
1240 // then adjust the amount to read
1241 //
1242 if ((FatFileInfo->FilePointer + BytesToRead) > FatFileInfo->FileSize)
1243 {
1244 BytesToRead = (FatFileInfo->FileSize - FatFileInfo->FilePointer);
1245 }
1246
1247 //
1248 // Ok, now we have to perform at most 3 calculations
1249 // I'll draw you a picture (using nifty ASCII art):
1250 //
1251 // CurrentFilePointer -+
1252 // |
1253 // +----------------+
1254 // |
1255 // +-----------+-----------+-----------+-----------+
1256 // | Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 |
1257 // +-----------+-----------+-----------+-----------+
1258 // | |
1259 // +---------------+--------------------+
1260 // |
1261 // BytesToRead -------+
1262 //
1263 // 1 - The first calculation (and read) will align
1264 // the file pointer with the next cluster.
1265 // boundary (if we are supposed to read that much)
1266 // 2 - The next calculation (and read) will read
1267 // in all the full clusters that the requested
1268 // amount of data would cover (in this case
1269 // clusters 2 & 3).
1270 // 3 - The last calculation (and read) would read
1271 // in the remainder of the data requested out of
1272 // the last cluster.
1273 //
1274
1275 BytesPerCluster = Volume->SectorsPerCluster * Volume->BytesPerSector;
1276
1277 //
1278 // Only do the first read if we
1279 // aren't aligned on a cluster boundary
1280 //
1281 if (FatFileInfo->FilePointer % BytesPerCluster)
1282 {
1283 //
1284 // Do the math for our first read
1285 //
1286 ClusterNumber = (FatFileInfo->FilePointer / BytesPerCluster);
1287 ClusterNumber = FatFileInfo->FileFatChain[ClusterNumber];
1288 OffsetInCluster = (FatFileInfo->FilePointer % BytesPerCluster);
1289 LengthInCluster = (BytesToRead > (BytesPerCluster - OffsetInCluster)) ? (BytesPerCluster - OffsetInCluster) : BytesToRead;
1290
1291 //
1292 // Now do the read and update BytesRead, BytesToRead, FilePointer, & Buffer
1293 //
1294 if (!FatReadPartialCluster(Volume, ClusterNumber, OffsetInCluster, LengthInCluster, Buffer))
1295 {
1296 return FALSE;
1297 }
1298 if (BytesRead != NULL)
1299 {
1300 *BytesRead += LengthInCluster;
1301 }
1302 BytesToRead -= LengthInCluster;
1303 FatFileInfo->FilePointer += LengthInCluster;
1304 Buffer = (PVOID)((ULONG_PTR)Buffer + LengthInCluster);
1305 }
1306
1307 //
1308 // Do the math for our second read (if any data left)
1309 //
1310 if (BytesToRead > 0)
1311 {
1312 //
1313 // Determine how many full clusters we need to read
1314 //
1315 NumberOfClusters = (BytesToRead / BytesPerCluster);
1316
1317 if (NumberOfClusters > 0)
1318 {
1319 ClusterNumber = (FatFileInfo->FilePointer / BytesPerCluster);
1320 ClusterNumber = FatFileInfo->FileFatChain[ClusterNumber];
1321
1322 //
1323 // Now do the read and update BytesRead, BytesToRead, FilePointer, & Buffer
1324 //
1325 if (!FatReadClusterChain(Volume, ClusterNumber, NumberOfClusters, Buffer))
1326 {
1327 return FALSE;
1328 }
1329 if (BytesRead != NULL)
1330 {
1331 *BytesRead += (NumberOfClusters * BytesPerCluster);
1332 }
1333 BytesToRead -= (NumberOfClusters * BytesPerCluster);
1334 FatFileInfo->FilePointer += (NumberOfClusters * BytesPerCluster);
1335 Buffer = (PVOID)((ULONG_PTR)Buffer + (NumberOfClusters * BytesPerCluster));
1336 }
1337 }
1338
1339 //
1340 // Do the math for our third read (if any data left)
1341 //
1342 if (BytesToRead > 0)
1343 {
1344 ClusterNumber = (FatFileInfo->FilePointer / BytesPerCluster);
1345 ClusterNumber = FatFileInfo->FileFatChain[ClusterNumber];
1346
1347 //
1348 // Now do the read and update BytesRead, BytesToRead, FilePointer, & Buffer
1349 //
1350 if (!FatReadPartialCluster(Volume, ClusterNumber, 0, BytesToRead, Buffer))
1351 {
1352 return FALSE;
1353 }
1354 if (BytesRead != NULL)
1355 {
1356 *BytesRead += BytesToRead;
1357 }
1358 FatFileInfo->FilePointer += BytesToRead;
1359 BytesToRead -= BytesToRead;
1360 Buffer = (PVOID)((ULONG_PTR)Buffer + BytesToRead);
1361 }
1362
1363 return TRUE;
1364 }
1365
1366 BOOLEAN FatReadVolumeSectors(PFAT_VOLUME_INFO Volume, ULONG SectorNumber, ULONG SectorCount, PVOID Buffer)
1367 {
1368 LARGE_INTEGER Position;
1369 ULONG Count;
1370 ARC_STATUS Status;
1371
1372 //TRACE("FatReadVolumeSectors(): SectorNumber %d, SectorCount %d, Buffer %p\n",
1373 // SectorNumber, SectorCount, Buffer);
1374
1375 //
1376 // Seek to right position
1377 //
1378 Position.QuadPart = (ULONGLONG)SectorNumber * 512;
1379 Status = ArcSeek(Volume->DeviceId, &Position, SeekAbsolute);
1380 if (Status != ESUCCESS)
1381 {
1382 TRACE("FatReadVolumeSectors() Failed to seek\n");
1383 return FALSE;
1384 }
1385
1386 //
1387 // Read data
1388 //
1389 Status = ArcRead(Volume->DeviceId, Buffer, SectorCount * 512, &Count);
1390 if (Status != ESUCCESS || Count != SectorCount * 512)
1391 {
1392 TRACE("FatReadVolumeSectors() Failed to read\n");
1393 return FALSE;
1394 }
1395
1396 // Return success
1397 return TRUE;
1398 }
1399
1400 ARC_STATUS FatClose(ULONG FileId)
1401 {
1402 PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
1403
1404 if (FileHandle->FileFatChain) FrLdrTempFree(FileHandle->FileFatChain, TAG_FAT_CHAIN);
1405 FrLdrTempFree(FileHandle, TAG_FAT_FILE);
1406
1407 return ESUCCESS;
1408 }
1409
1410 ARC_STATUS FatGetFileInformation(ULONG FileId, FILEINFORMATION* Information)
1411 {
1412 PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
1413
1414 RtlZeroMemory(Information, sizeof(*Information));
1415 Information->EndingAddress.LowPart = FileHandle->FileSize;
1416 Information->CurrentAddress.LowPart = FileHandle->FilePointer;
1417
1418 TRACE("FatGetFileInformation(%lu) -> FileSize = %lu, FilePointer = 0x%lx\n",
1419 FileId, Information->EndingAddress.LowPart, Information->CurrentAddress.LowPart);
1420
1421 return ESUCCESS;
1422 }
1423
1424 ARC_STATUS FatOpen(CHAR* Path, OPENMODE OpenMode, ULONG* FileId)
1425 {
1426 PFAT_VOLUME_INFO FatVolume;
1427 FAT_FILE_INFO TempFileInfo;
1428 PFAT_FILE_INFO FileHandle;
1429 ULONG DeviceId;
1430 BOOLEAN IsDirectory;
1431 ARC_STATUS Status;
1432
1433 if (OpenMode != OpenReadOnly && OpenMode != OpenDirectory)
1434 return EACCES;
1435
1436 DeviceId = FsGetDeviceId(*FileId);
1437 FatVolume = FatVolumes[DeviceId];
1438
1439 TRACE("FatOpen() FileName = %s\n", Path);
1440
1441 RtlZeroMemory(&TempFileInfo, sizeof(TempFileInfo));
1442 Status = FatLookupFile(FatVolume, Path, DeviceId, &TempFileInfo);
1443 if (Status != ESUCCESS)
1444 return ENOENT;
1445
1446 //
1447 // Check if caller opened what he expected (dir vs file)
1448 //
1449 IsDirectory = (TempFileInfo.Attributes & ATTR_DIRECTORY) != 0;
1450 if (IsDirectory && OpenMode != OpenDirectory)
1451 return EISDIR;
1452 else if (!IsDirectory && OpenMode != OpenReadOnly)
1453 return ENOTDIR;
1454
1455 FileHandle = FrLdrTempAlloc(sizeof(FAT_FILE_INFO), TAG_FAT_FILE);
1456 if (!FileHandle)
1457 return ENOMEM;
1458
1459 RtlCopyMemory(FileHandle, &TempFileInfo, sizeof(FAT_FILE_INFO));
1460 FileHandle->Volume = FatVolume;
1461
1462 FsSetDeviceSpecific(*FileId, FileHandle);
1463 return ESUCCESS;
1464 }
1465
1466 ARC_STATUS FatRead(ULONG FileId, VOID* Buffer, ULONG N, ULONG* Count)
1467 {
1468 PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
1469 BOOLEAN Success;
1470
1471 //
1472 // Call old read method
1473 //
1474 Success = FatReadFile(FileHandle, N, Count, Buffer);
1475
1476 //
1477 // Check for success
1478 //
1479 if (Success)
1480 return ESUCCESS;
1481 else
1482 return EIO;
1483 }
1484
1485 ARC_STATUS FatSeek(ULONG FileId, LARGE_INTEGER* Position, SEEKMODE SeekMode)
1486 {
1487 PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
1488
1489 TRACE("FatSeek() NewFilePointer = %lu\n", Position->LowPart);
1490
1491 if (SeekMode != SeekAbsolute)
1492 return EINVAL;
1493 if (Position->HighPart != 0)
1494 return EINVAL;
1495 if (Position->LowPart >= FileHandle->FileSize)
1496 return EINVAL;
1497
1498 FileHandle->FilePointer = Position->LowPart;
1499 return ESUCCESS;
1500 }
1501
1502 const DEVVTBL FatFuncTable =
1503 {
1504 FatClose,
1505 FatGetFileInformation,
1506 FatOpen,
1507 FatRead,
1508 FatSeek,
1509 L"fastfat",
1510 };
1511
1512 const DEVVTBL* FatMount(ULONG DeviceId)
1513 {
1514 PFAT_VOLUME_INFO Volume;
1515 UCHAR Buffer[512];
1516 PFAT_BOOTSECTOR BootSector = (PFAT_BOOTSECTOR)Buffer;
1517 PFAT32_BOOTSECTOR BootSector32 = (PFAT32_BOOTSECTOR)Buffer;
1518 PFATX_BOOTSECTOR BootSectorX = (PFATX_BOOTSECTOR)Buffer;
1519 FILEINFORMATION FileInformation;
1520 LARGE_INTEGER Position;
1521 ULONG Count;
1522 ULARGE_INTEGER SectorCount;
1523 ARC_STATUS Status;
1524
1525 //
1526 // Allocate data for volume information
1527 //
1528 Volume = FrLdrTempAlloc(sizeof(FAT_VOLUME_INFO), TAG_FAT_VOLUME);
1529 if (!Volume)
1530 return NULL;
1531 RtlZeroMemory(Volume, sizeof(FAT_VOLUME_INFO));
1532
1533 //
1534 // Read the BootSector
1535 //
1536 Position.HighPart = 0;
1537 Position.LowPart = 0;
1538 Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
1539 if (Status != ESUCCESS)
1540 {
1541 FrLdrTempFree(Volume, TAG_FAT_VOLUME);
1542 return NULL;
1543 }
1544 Status = ArcRead(DeviceId, Buffer, sizeof(Buffer), &Count);
1545 if (Status != ESUCCESS || Count != sizeof(Buffer))
1546 {
1547 FrLdrTempFree(Volume, TAG_FAT_VOLUME);
1548 return NULL;
1549 }
1550
1551 //
1552 // Check if BootSector is valid. If no, return early
1553 //
1554 if (!RtlEqualMemory(BootSector->FileSystemType, "FAT12 ", 8) &&
1555 !RtlEqualMemory(BootSector->FileSystemType, "FAT16 ", 8) &&
1556 !RtlEqualMemory(BootSector32->FileSystemType, "FAT32 ", 8) &&
1557 !RtlEqualMemory(BootSectorX->FileSystemType, "FATX", 4))
1558 {
1559 FrLdrTempFree(Volume, TAG_FAT_VOLUME);
1560 return NULL;
1561 }
1562
1563 //
1564 // Determine sector count
1565 //
1566 Status = ArcGetFileInformation(DeviceId, &FileInformation);
1567 if (Status != ESUCCESS)
1568 {
1569 FrLdrTempFree(Volume, TAG_FAT_VOLUME);
1570 return NULL;
1571 }
1572 SectorCount.HighPart = FileInformation.EndingAddress.HighPart;
1573 SectorCount.LowPart = FileInformation.EndingAddress.LowPart;
1574 SectorCount.QuadPart /= SECTOR_SIZE;
1575
1576 //
1577 // Keep device id
1578 //
1579 Volume->DeviceId = DeviceId;
1580
1581 //
1582 // Really open the volume
1583 //
1584 if (!FatOpenVolume(Volume, BootSector, SectorCount.QuadPart))
1585 {
1586 FrLdrTempFree(Volume, TAG_FAT_VOLUME);
1587 return NULL;
1588 }
1589
1590 //
1591 // Remember FAT volume information
1592 //
1593 FatVolumes[DeviceId] = Volume;
1594
1595 //
1596 // Return success
1597 //
1598 return &FatFuncTable;
1599 }
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