projects / reactos.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
history | raw | HEAD
[FREELDR]
[reactos.git] / reactos / boot / freeldr / freeldr / 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 #define NDEBUG
24 #include <debug.h>
25
26 DBG_DEFAULT_CHANNEL(FILESYSTEM);
27
28 ULONG FatDetermineFatType(PFAT_BOOTSECTOR FatBootSector, ULONGLONG PartitionSectorCount);
29 PVOID FatBufferDirectory(PFAT_VOLUME_INFO Volume, ULONG DirectoryStartCluster, ULONG* EntryCountPointer, BOOLEAN RootDirectory);
30 BOOLEAN FatSearchDirectoryBufferForFile(PFAT_VOLUME_INFO Volume, PVOID DirectoryBuffer, ULONG EntryCount, PCHAR FileName, PFAT_FILE_INFO FatFileInfoPointer);
31 LONG FatLookupFile(PFAT_VOLUME_INFO Volume, PCSTR FileName, ULONG DeviceId, PFAT_FILE_INFO FatFileInfoPointer);
32 void FatParseShortFileName(PCHAR Buffer, PDIRENTRY DirEntry);
33 BOOLEAN FatGetFatEntry(PFAT_VOLUME_INFO Volume, ULONG Cluster, ULONG* ClusterPointer);
34 ULONG FatCountClustersInChain(PFAT_VOLUME_INFO Volume, ULONG StartCluster);
35 ULONG* FatGetClusterChainArray(PFAT_VOLUME_INFO Volume, ULONG StartCluster);
36 BOOLEAN FatReadClusterChain(PFAT_VOLUME_INFO Volume, ULONG StartClusterNumber, ULONG NumberOfClusters, PVOID Buffer);
37 BOOLEAN FatReadPartialCluster(PFAT_VOLUME_INFO Volume, ULONG ClusterNumber, ULONG StartingOffset, ULONG Length, PVOID Buffer);
38 BOOLEAN FatReadVolumeSectors(PFAT_VOLUME_INFO Volume, ULONG SectorNumber, ULONG SectorCount, PVOID Buffer);
39
40 typedef struct _FAT_VOLUME_INFO
41 {
42 ULONG BytesPerSector; /* Number of bytes per sector */
43 ULONG SectorsPerCluster; /* Number of sectors per cluster */
44 ULONG FatSectorStart; /* Starting sector of 1st FAT table */
45 ULONG ActiveFatSectorStart; /* Starting sector of active FAT table */
46 ULONG NumberOfFats; /* Number of FAT tables */
47 ULONG SectorsPerFat; /* Sectors per FAT table */
48 ULONG RootDirSectorStart; /* Starting sector of the root directory (non-fat32) */
49 ULONG RootDirSectors; /* Number of sectors of the root directory (non-fat32) */
50 ULONG RootDirStartCluster; /* Starting cluster number of the root directory (fat32 only) */
51 ULONG DataSectorStart; /* Starting sector of the data area */
52 ULONG FatType; /* FAT12, FAT16, FAT32, FATX16 or FATX32 */
53 ULONG DeviceId;
54 } FAT_VOLUME_INFO;
55
56 PFAT_VOLUME_INFO FatVolumes[MAX_FDS];
57
58 VOID FatSwapFatBootSector(PFAT_BOOTSECTOR Obj)
59 {
60 SW(Obj, BytesPerSector);
61 SW(Obj, ReservedSectors);
62 SW(Obj, RootDirEntries);
63 SW(Obj, TotalSectors);
64 SW(Obj, SectorsPerFat);
65 SW(Obj, SectorsPerTrack);
66 SW(Obj, NumberOfHeads);
67 SD(Obj, HiddenSectors);
68 SD(Obj, TotalSectorsBig);
69 SD(Obj, VolumeSerialNumber);
70 SW(Obj, BootSectorMagic);
71 }
72
73 VOID FatSwapFat32BootSector(PFAT32_BOOTSECTOR Obj)
74 {
75 SW(Obj, BytesPerSector);
76 SW(Obj, ReservedSectors);
77 SW(Obj, RootDirEntries);
78 SW(Obj, TotalSectors);
79 SW(Obj, SectorsPerFat);
80 SW(Obj, NumberOfHeads);
81 SD(Obj, HiddenSectors);
82 SD(Obj, TotalSectorsBig);
83 SD(Obj, SectorsPerFatBig);
84 SW(Obj, ExtendedFlags);
85 SW(Obj, FileSystemVersion);
86 SD(Obj, RootDirStartCluster);
87 SW(Obj, FsInfo);
88 SW(Obj, BackupBootSector);
89 SD(Obj, VolumeSerialNumber);
90 SW(Obj, BootSectorMagic);
91 }
92
93 VOID FatSwapFatXBootSector(PFATX_BOOTSECTOR Obj)
94 {
95 SD(Obj, VolumeSerialNumber);
96 SD(Obj, SectorsPerCluster);
97 SW(Obj, NumberOfFats);
98 }
99
100 VOID FatSwapDirEntry(PDIRENTRY Obj)
101 {
102 SW(Obj, CreateTime);
103 SW(Obj, CreateDate);
104 SW(Obj, LastAccessDate);
105 SW(Obj, ClusterHigh);
106 SW(Obj, Time);
107 SW(Obj, Date);
108 SW(Obj, ClusterLow);
109 SD(Obj, Size);
110 }
111
112 VOID FatSwapLFNDirEntry(PLFN_DIRENTRY Obj)
113 {
114 int i;
115 SW(Obj, StartCluster);
116 for(i = 0; i < 5; i++)
117 Obj->Name0_4[i] = SWAPW(Obj->Name0_4[i]);
118 for(i = 0; i < 6; i++)
119 Obj->Name5_10[i] = SWAPW(Obj->Name5_10[i]);
120 for(i = 0; i < 2; i++)
121 Obj->Name11_12[i] = SWAPW(Obj->Name11_12[i]);
122 }
123
124 VOID FatSwapFatXDirEntry(PFATX_DIRENTRY Obj)
125 {
126 SD(Obj, StartCluster);
127 SD(Obj, Size);
128 SW(Obj, Time);
129 SW(Obj, Date);
130 SW(Obj, CreateTime);
131 SW(Obj, CreateDate);
132 SW(Obj, LastAccessTime);
133 SW(Obj, LastAccessDate);
134 }
135
136 BOOLEAN FatOpenVolume(PFAT_VOLUME_INFO Volume, PFAT_BOOTSECTOR BootSector, ULONGLONG PartitionSectorCount)
137 {
138 char ErrMsg[80];
139 ULONG FatSize;
140 PFAT_BOOTSECTOR FatVolumeBootSector;
141 PFAT32_BOOTSECTOR Fat32VolumeBootSector;
142 PFATX_BOOTSECTOR FatXVolumeBootSector;
143
144 TRACE("FatOpenVolume() DeviceId = %d\n", Volume->DeviceId);
145
146 //
147 // Allocate the memory to hold the boot sector
148 //
149 FatVolumeBootSector = (PFAT_BOOTSECTOR)BootSector;
150 Fat32VolumeBootSector = (PFAT32_BOOTSECTOR)BootSector;
151 FatXVolumeBootSector = (PFATX_BOOTSECTOR)BootSector;
152
153 // Get the FAT type
154 Volume->FatType = FatDetermineFatType(FatVolumeBootSector, PartitionSectorCount);
155
156 // Dump boot sector (and swap it for big endian systems)
157 TRACE("Dumping boot sector:\n");
158 if (ISFATX(Volume->FatType))
159 {
160 FatSwapFatXBootSector(FatXVolumeBootSector);
161 TRACE("sizeof(FATX_BOOTSECTOR) = 0x%x.\n", sizeof(FATX_BOOTSECTOR));
162
163 TRACE("FileSystemType: %c%c%c%c.\n", FatXVolumeBootSector->FileSystemType[0], FatXVolumeBootSector->FileSystemType[1], FatXVolumeBootSector->FileSystemType[2], FatXVolumeBootSector->FileSystemType[3]);
164 TRACE("VolumeSerialNumber: 0x%x\n", FatXVolumeBootSector->VolumeSerialNumber);
165 TRACE("SectorsPerCluster: %d\n", FatXVolumeBootSector->SectorsPerCluster);
166 TRACE("NumberOfFats: %d\n", FatXVolumeBootSector->NumberOfFats);
167 TRACE("Unknown: 0x%x\n", FatXVolumeBootSector->Unknown);
168
169 TRACE("FatType %s\n", Volume->FatType == FATX16 ? "FATX16" : "FATX32");
170
171 }
172 else if (Volume->FatType == FAT32)
173 {
174 FatSwapFat32BootSector(Fat32VolumeBootSector);
175 TRACE("sizeof(FAT32_BOOTSECTOR) = 0x%x.\n", sizeof(FAT32_BOOTSECTOR));
176
177 TRACE("JumpBoot: 0x%x 0x%x 0x%x\n", Fat32VolumeBootSector->JumpBoot[0], Fat32VolumeBootSector->JumpBoot[1], Fat32VolumeBootSector->JumpBoot[2]);
178 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]);
179 TRACE("BytesPerSector: %d\n", Fat32VolumeBootSector->BytesPerSector);
180 TRACE("SectorsPerCluster: %d\n", Fat32VolumeBootSector->SectorsPerCluster);
181 TRACE("ReservedSectors: %d\n", Fat32VolumeBootSector->ReservedSectors);
182 TRACE("NumberOfFats: %d\n", Fat32VolumeBootSector->NumberOfFats);
183 TRACE("RootDirEntries: %d\n", Fat32VolumeBootSector->RootDirEntries);
184 TRACE("TotalSectors: %d\n", Fat32VolumeBootSector->TotalSectors);
185 TRACE("MediaDescriptor: 0x%x\n", Fat32VolumeBootSector->MediaDescriptor);
186 TRACE("SectorsPerFat: %d\n", Fat32VolumeBootSector->SectorsPerFat);
187 TRACE("SectorsPerTrack: %d\n", Fat32VolumeBootSector->SectorsPerTrack);
188 TRACE("NumberOfHeads: %d\n", Fat32VolumeBootSector->NumberOfHeads);
189 TRACE("HiddenSectors: %d\n", Fat32VolumeBootSector->HiddenSectors);
190 TRACE("TotalSectorsBig: %d\n", Fat32VolumeBootSector->TotalSectorsBig);
191 TRACE("SectorsPerFatBig: %d\n", Fat32VolumeBootSector->SectorsPerFatBig);
192 TRACE("ExtendedFlags: 0x%x\n", Fat32VolumeBootSector->ExtendedFlags);
193 TRACE("FileSystemVersion: 0x%x\n", Fat32VolumeBootSector->FileSystemVersion);
194 TRACE("RootDirStartCluster: %d\n", Fat32VolumeBootSector->RootDirStartCluster);
195 TRACE("FsInfo: %d\n", Fat32VolumeBootSector->FsInfo);
196 TRACE("BackupBootSector: %d\n", Fat32VolumeBootSector->BackupBootSector);
197 TRACE("Reserved: 0x%x\n", Fat32VolumeBootSector->Reserved);
198 TRACE("DriveNumber: 0x%x\n", Fat32VolumeBootSector->DriveNumber);
199 TRACE("Reserved1: 0x%x\n", Fat32VolumeBootSector->Reserved1);
200 TRACE("BootSignature: 0x%x\n", Fat32VolumeBootSector->BootSignature);
201 TRACE("VolumeSerialNumber: 0x%x\n", Fat32VolumeBootSector->VolumeSerialNumber);
202 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]);
203 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]);
204 TRACE("BootSectorMagic: 0x%x\n", Fat32VolumeBootSector->BootSectorMagic);
205 }
206 else
207 {
208 FatSwapFatBootSector(FatVolumeBootSector);
209 TRACE("sizeof(FAT_BOOTSECTOR) = 0x%x.\n", sizeof(FAT_BOOTSECTOR));
210
211 TRACE("JumpBoot: 0x%x 0x%x 0x%x\n", FatVolumeBootSector->JumpBoot[0], FatVolumeBootSector->JumpBoot[1], FatVolumeBootSector->JumpBoot[2]);
212 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]);
213 TRACE("BytesPerSector: %d\n", FatVolumeBootSector->BytesPerSector);
214 TRACE("SectorsPerCluster: %d\n", FatVolumeBootSector->SectorsPerCluster);
215 TRACE("ReservedSectors: %d\n", FatVolumeBootSector->ReservedSectors);
216 TRACE("NumberOfFats: %d\n", FatVolumeBootSector->NumberOfFats);
217 TRACE("RootDirEntries: %d\n", FatVolumeBootSector->RootDirEntries);
218 TRACE("TotalSectors: %d\n", FatVolumeBootSector->TotalSectors);
219 TRACE("MediaDescriptor: 0x%x\n", FatVolumeBootSector->MediaDescriptor);
220 TRACE("SectorsPerFat: %d\n", FatVolumeBootSector->SectorsPerFat);
221 TRACE("SectorsPerTrack: %d\n", FatVolumeBootSector->SectorsPerTrack);
222 TRACE("NumberOfHeads: %d\n", FatVolumeBootSector->NumberOfHeads);
223 TRACE("HiddenSectors: %d\n", FatVolumeBootSector->HiddenSectors);
224 TRACE("TotalSectorsBig: %d\n", FatVolumeBootSector->TotalSectorsBig);
225 TRACE("DriveNumber: 0x%x\n", FatVolumeBootSector->DriveNumber);
226 TRACE("Reserved1: 0x%x\n", FatVolumeBootSector->Reserved1);
227 TRACE("BootSignature: 0x%x\n", FatVolumeBootSector->BootSignature);
228 TRACE("VolumeSerialNumber: 0x%x\n", FatVolumeBootSector->VolumeSerialNumber);
229 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]);
230 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]);
231 TRACE("BootSectorMagic: 0x%x\n", FatVolumeBootSector->BootSectorMagic);
232 }
233
234 //
235 // Check the boot sector magic
236 //
237 if (! ISFATX(Volume->FatType) && FatVolumeBootSector->BootSectorMagic != 0xaa55)
238 {
239 sprintf(ErrMsg, "Invalid boot sector magic (expected 0xaa55 found 0x%x)",
240 FatVolumeBootSector->BootSectorMagic);
241 FileSystemError(ErrMsg);
242 return FALSE;
243 }
244
245 //
246 // Check the FAT cluster size
247 // We do not support clusters bigger than 64k
248 //
249 if ((ISFATX(Volume->FatType) && 64 * 1024 < FatXVolumeBootSector->SectorsPerCluster * 512) ||
250 (! ISFATX(Volume->FatType) && 64 * 1024 < FatVolumeBootSector->SectorsPerCluster * FatVolumeBootSector->BytesPerSector))
251 {
252 FileSystemError("This file system has cluster sizes bigger than 64k.\nFreeLoader does not support this.");
253 return FALSE;
254 }
255
256 //
257 // Get the sectors per FAT,
258 // root directory starting sector,
259 // and data sector start
260 //
261 if (ISFATX(Volume->FatType))
262 {
263 Volume->BytesPerSector = 512;
264 Volume->SectorsPerCluster = SWAPD(FatXVolumeBootSector->SectorsPerCluster);
265 Volume->FatSectorStart = (4096 / Volume->BytesPerSector);
266 Volume->ActiveFatSectorStart = Volume->FatSectorStart;
267 Volume->NumberOfFats = 1;
268 FatSize = (ULONG)(PartitionSectorCount / Volume->SectorsPerCluster *
269 (Volume->FatType == FATX16 ? 2 : 4));
270 Volume->SectorsPerFat = (((FatSize + 4095) / 4096) * 4096) / Volume->BytesPerSector;
271
272 Volume->RootDirSectorStart = Volume->FatSectorStart + Volume->NumberOfFats * Volume->SectorsPerFat;
273 Volume->RootDirSectors = FatXVolumeBootSector->SectorsPerCluster;
274
275 Volume->DataSectorStart = Volume->RootDirSectorStart + Volume->RootDirSectors;
276 }
277 else if (Volume->FatType != FAT32)
278 {
279 Volume->BytesPerSector = FatVolumeBootSector->BytesPerSector;
280 Volume->SectorsPerCluster = FatVolumeBootSector->SectorsPerCluster;
281 Volume->FatSectorStart = FatVolumeBootSector->ReservedSectors;
282 Volume->ActiveFatSectorStart = Volume->FatSectorStart;
283 Volume->NumberOfFats = FatVolumeBootSector->NumberOfFats;
284 Volume->SectorsPerFat = FatVolumeBootSector->SectorsPerFat;
285
286 Volume->RootDirSectorStart = Volume->FatSectorStart + Volume->NumberOfFats * Volume->SectorsPerFat;
287 Volume->RootDirSectors = ((FatVolumeBootSector->RootDirEntries * 32) + (Volume->BytesPerSector - 1)) / Volume->BytesPerSector;
288
289 Volume->DataSectorStart = Volume->RootDirSectorStart + Volume->RootDirSectors;
290 }
291 else
292 {
293 Volume->BytesPerSector = Fat32VolumeBootSector->BytesPerSector;
294 Volume->SectorsPerCluster = Fat32VolumeBootSector->SectorsPerCluster;
295 Volume->FatSectorStart = Fat32VolumeBootSector->ReservedSectors;
296 Volume->ActiveFatSectorStart = Volume->FatSectorStart +
297 ((Fat32VolumeBootSector->ExtendedFlags & 0x80) ? ((Fat32VolumeBootSector->ExtendedFlags & 0x0f) * Fat32VolumeBootSector->SectorsPerFatBig) : 0);
298 Volume->NumberOfFats = Fat32VolumeBootSector->NumberOfFats;
299 Volume->SectorsPerFat = Fat32VolumeBootSector->SectorsPerFatBig;
300
301 Volume->RootDirStartCluster = Fat32VolumeBootSector->RootDirStartCluster;
302 Volume->DataSectorStart = Volume->FatSectorStart + Volume->NumberOfFats * Volume->SectorsPerFat;
303
304 //
305 // Check version
306 // we only work with version 0
307 //
308 if (Fat32VolumeBootSector->FileSystemVersion != 0)
309 {
310 FileSystemError("FreeLoader is too old to work with this FAT32 filesystem.\nPlease update FreeLoader.");
311 return FALSE;
312 }
313 }
314
315 return TRUE;
316 }
317
318 ULONG FatDetermineFatType(PFAT_BOOTSECTOR FatBootSector, ULONGLONG PartitionSectorCount)
319 {
320 ULONG RootDirSectors;
321 ULONG DataSectorCount;
322 ULONG SectorsPerFat;
323 ULONG TotalSectors;
324 ULONG CountOfClusters;
325 PFAT32_BOOTSECTOR Fat32BootSector = (PFAT32_BOOTSECTOR)FatBootSector;
326 PFATX_BOOTSECTOR FatXBootSector = (PFATX_BOOTSECTOR)FatBootSector;
327
328 if (0 == strncmp(FatXBootSector->FileSystemType, "FATX", 4))
329 {
330 CountOfClusters = (ULONG)(PartitionSectorCount / FatXBootSector->SectorsPerCluster);
331 if (CountOfClusters < 65525)
332 {
333 /* Volume is FATX16 */
334 return FATX16;
335 }
336 else
337 {
338 /* Volume is FAT32 */
339 return FATX32;
340 }
341 }
342 else
343 {
344 RootDirSectors = ((SWAPW(FatBootSector->RootDirEntries) * 32) + (SWAPW(FatBootSector->BytesPerSector) - 1)) / SWAPW(FatBootSector->BytesPerSector);
345 SectorsPerFat = SWAPW(FatBootSector->SectorsPerFat) ? SWAPW(FatBootSector->SectorsPerFat) : SWAPD(Fat32BootSector->SectorsPerFatBig);
346 TotalSectors = SWAPW(FatBootSector->TotalSectors) ? SWAPW(FatBootSector->TotalSectors) : SWAPD(FatBootSector->TotalSectorsBig);
347 DataSectorCount = TotalSectors - (SWAPW(FatBootSector->ReservedSectors) + (FatBootSector->NumberOfFats * SectorsPerFat) + RootDirSectors);
348
349 //mjl
350 if (FatBootSector->SectorsPerCluster == 0)
351 CountOfClusters = 0;
352 else
353 CountOfClusters = DataSectorCount / FatBootSector->SectorsPerCluster;
354
355 if (CountOfClusters < 4085)
356 {
357 /* Volume is FAT12 */
358 return FAT12;
359 }
360 else if (CountOfClusters < 65525)
361 {
362 /* Volume is FAT16 */
363 return FAT16;
364 }
365 else
366 {
367 /* Volume is FAT32 */
368 return FAT32;
369 }
370 }
371 }
372
373 PVOID FatBufferDirectory(PFAT_VOLUME_INFO Volume, ULONG DirectoryStartCluster, ULONG *DirectorySize, BOOLEAN RootDirectory)
374 {
375 PVOID DirectoryBuffer;
376
377 TRACE("FatBufferDirectory() DirectoryStartCluster = %d RootDirectory = %s\n", DirectoryStartCluster, (RootDirectory ? "TRUE" : "FALSE"));
378
379 /*
380 * For FAT32, the root directory is nothing special. We can treat it the same
381 * as a subdirectory.
382 */
383 if (RootDirectory && Volume->FatType == FAT32)
384 {
385 DirectoryStartCluster = Volume->RootDirStartCluster;
386 RootDirectory = FALSE;
387 }
388
389 //
390 // Calculate the size of the directory
391 //
392 if (RootDirectory)
393 {
394 *DirectorySize = Volume->RootDirSectors * Volume->BytesPerSector;
395 }
396 else
397 {
398 *DirectorySize = FatCountClustersInChain(Volume, DirectoryStartCluster) * Volume->SectorsPerCluster * Volume->BytesPerSector;
399 }
400
401 //
402 // Attempt to allocate memory for directory buffer
403 //
404 TRACE("Trying to allocate (DirectorySize) %d bytes.\n", *DirectorySize);
405 DirectoryBuffer = MmAllocateMemory(*DirectorySize);
406
407 if (DirectoryBuffer == NULL)
408 {
409 return NULL;
410 }
411
412 //
413 // Now read directory contents into DirectoryBuffer
414 //
415 if (RootDirectory)
416 {
417 if (!FatReadVolumeSectors(Volume, Volume->RootDirSectorStart, Volume->RootDirSectors, DirectoryBuffer))
418 {
419 MmFreeMemory(DirectoryBuffer);
420 return NULL;
421 }
422 }
423 else
424 {
425 if (!FatReadClusterChain(Volume, DirectoryStartCluster, 0xFFFFFFFF, DirectoryBuffer))
426 {
427 MmFreeMemory(DirectoryBuffer);
428 return NULL;
429 }
430 }
431
432 return DirectoryBuffer;
433 }
434
435 BOOLEAN FatSearchDirectoryBufferForFile(PFAT_VOLUME_INFO Volume, PVOID DirectoryBuffer, ULONG DirectorySize, PCHAR FileName, PFAT_FILE_INFO FatFileInfoPointer)
436 {
437 ULONG EntryCount;
438 ULONG CurrentEntry;
439 CHAR LfnNameBuffer[265];
440 CHAR ShortNameBuffer[20];
441 ULONG StartCluster;
442 DIRENTRY OurDirEntry;
443 LFN_DIRENTRY OurLfnDirEntry;
444 PDIRENTRY DirEntry = &OurDirEntry;
445 PLFN_DIRENTRY LfnDirEntry = &OurLfnDirEntry;
446
447 EntryCount = DirectorySize / sizeof(DIRENTRY);
448
449 TRACE("FatSearchDirectoryBufferForFile() DirectoryBuffer = 0x%x EntryCount = %d FileName = %s\n", DirectoryBuffer, EntryCount, FileName);
450
451 memset(ShortNameBuffer, 0, 13 * sizeof(CHAR));
452 memset(LfnNameBuffer, 0, 261 * sizeof(CHAR));
453
454 for (CurrentEntry=0; CurrentEntry<EntryCount; CurrentEntry++, DirectoryBuffer = ((PDIRENTRY)DirectoryBuffer)+1)
455 {
456 OurLfnDirEntry = *((PLFN_DIRENTRY) DirectoryBuffer);
457 FatSwapLFNDirEntry(LfnDirEntry);
458 OurDirEntry = *((PDIRENTRY) DirectoryBuffer);
459 FatSwapDirEntry(DirEntry);
460
461 //TRACE("Dumping directory entry %d:\n", CurrentEntry);
462 //DbgDumpBuffer(DPRINT_FILESYSTEM, DirEntry, sizeof(DIRENTRY));
463
464 //
465 // Check if this is the last file in the directory
466 // If DirEntry[0] == 0x00 then that means all the
467 // entries after this one are unused. If this is the
468 // last entry then we didn't find the file in this directory.
469 //
470 if (DirEntry->FileName[0] == '\0')
471 {
472 return FALSE;
473 }
474
475 //
476 // Check if this is a deleted entry or not
477 //
478 if (DirEntry->FileName[0] == '\xE5')
479 {
480 memset(ShortNameBuffer, 0, 13 * sizeof(CHAR));
481 memset(LfnNameBuffer, 0, 261 * sizeof(CHAR));
482 continue;
483 }
484
485 //
486 // Check if this is a LFN entry
487 // If so it needs special handling
488 //
489 if (DirEntry->Attr == ATTR_LONG_NAME)
490 {
491 //
492 // Check to see if this is a deleted LFN entry, if so continue
493 //
494 if (LfnDirEntry->SequenceNumber & 0x80)
495 {
496 continue;
497 }
498
499 //
500 // Mask off high two bits of sequence number
501 // and make the sequence number zero-based
502 //
503 LfnDirEntry->SequenceNumber &= 0x3F;
504 LfnDirEntry->SequenceNumber--;
505
506 //
507 // Get all 13 LFN entry characters
508 //
509 if (LfnDirEntry->Name0_4[0] != 0xFFFF)
510 {
511 LfnNameBuffer[0 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[0];
512 }
513 if (LfnDirEntry->Name0_4[1] != 0xFFFF)
514 {
515 LfnNameBuffer[1 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[1];
516 }
517 if (LfnDirEntry->Name0_4[2] != 0xFFFF)
518 {
519 LfnNameBuffer[2 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[2];
520 }
521 if (LfnDirEntry->Name0_4[3] != 0xFFFF)
522 {
523 LfnNameBuffer[3 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[3];
524 }
525 if (LfnDirEntry->Name0_4[4] != 0xFFFF)
526 {
527 LfnNameBuffer[4 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[4];
528 }
529 if (LfnDirEntry->Name5_10[0] != 0xFFFF)
530 {
531 LfnNameBuffer[5 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[0];
532 }
533 if (LfnDirEntry->Name5_10[1] != 0xFFFF)
534 {
535 LfnNameBuffer[6 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[1];
536 }
537 if (LfnDirEntry->Name5_10[2] != 0xFFFF)
538 {
539 LfnNameBuffer[7 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[2];
540 }
541 if (LfnDirEntry->Name5_10[3] != 0xFFFF)
542 {
543 LfnNameBuffer[8 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[3];
544 }
545 if (LfnDirEntry->Name5_10[4] != 0xFFFF)
546 {
547 LfnNameBuffer[9 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[4];
548 }
549 if (LfnDirEntry->Name5_10[5] != 0xFFFF)
550 {
551 LfnNameBuffer[10 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[5];
552 }
553 if (LfnDirEntry->Name11_12[0] != 0xFFFF)
554 {
555 LfnNameBuffer[11 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name11_12[0];
556 }
557 if (LfnDirEntry->Name11_12[1] != 0xFFFF)
558 {
559 LfnNameBuffer[12 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name11_12[1];
560 }
561
562 //TRACE("Dumping long name buffer:\n");
563 //DbgDumpBuffer(DPRINT_FILESYSTEM, LfnNameBuffer, 260);
564
565 continue;
566 }
567
568 //
569 // Check for the volume label attribute
570 // and skip over this entry if found
571 //
572 if (DirEntry->Attr & ATTR_VOLUMENAME)
573 {
574 memset(ShortNameBuffer, 0, 13 * sizeof(UCHAR));
575 memset(LfnNameBuffer, 0, 261 * sizeof(UCHAR));
576 continue;
577 }
578
579 //
580 // If we get here then we've found a short file name
581 // entry and LfnNameBuffer contains the long file
582 // name or zeroes. All we have to do now is see if the
583 // file name matches either the short or long file name
584 // and fill in the FAT_FILE_INFO structure if it does
585 // or zero our buffers and continue looking.
586 //
587
588 //
589 // Get short file name
590 //
591 FatParseShortFileName(ShortNameBuffer, DirEntry);
592
593 //TRACE("Entry: %d LFN = %s\n", CurrentEntry, LfnNameBuffer);
594 //TRACE("Entry: %d DOS name = %s\n", CurrentEntry, ShortNameBuffer);
595
596 //
597 // See if the file name matches either the short or long name
598 //
599 if (((strlen(FileName) == strlen(LfnNameBuffer)) && (_stricmp(FileName, LfnNameBuffer) == 0)) ||
600 ((strlen(FileName) == strlen(ShortNameBuffer)) && (_stricmp(FileName, ShortNameBuffer) == 0))) {
601 //
602 // We found the entry, now fill in the FAT_FILE_INFO struct
603 //
604 FatFileInfoPointer->Attributes = DirEntry->Attr;
605 FatFileInfoPointer->FileSize = DirEntry->Size;
606 FatFileInfoPointer->FilePointer = 0;
607
608 TRACE("MSDOS Directory Entry:\n");
609 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]);
610 TRACE("Attr = 0x%x\n", DirEntry->Attr);
611 TRACE("ReservedNT = 0x%x\n", DirEntry->ReservedNT);
612 TRACE("TimeInTenths = %d\n", DirEntry->TimeInTenths);
613 TRACE("CreateTime = %d\n", DirEntry->CreateTime);
614 TRACE("CreateDate = %d\n", DirEntry->CreateDate);
615 TRACE("LastAccessDate = %d\n", DirEntry->LastAccessDate);
616 TRACE("ClusterHigh = 0x%x\n", DirEntry->ClusterHigh);
617 TRACE("Time = %d\n", DirEntry->Time);
618 TRACE("Date = %d\n", DirEntry->Date);
619 TRACE("ClusterLow = 0x%x\n", DirEntry->ClusterLow);
620 TRACE("Size = %d\n", DirEntry->Size);
621
622 //
623 // Get the cluster chain
624 //
625 StartCluster = ((ULONG)DirEntry->ClusterHigh << 16) + DirEntry->ClusterLow;
626 TRACE("StartCluster = 0x%x\n", StartCluster);
627 FatFileInfoPointer->FileFatChain = FatGetClusterChainArray(Volume, StartCluster);
628
629 //
630 // See if memory allocation failed
631 //
632 if (FatFileInfoPointer->FileFatChain == NULL)
633 {
634 return FALSE;
635 }
636
637 return TRUE;
638 }
639
640 //
641 // Nope, no match - zero buffers and continue looking
642 //
643 memset(ShortNameBuffer, 0, 13 * sizeof(UCHAR));
644 memset(LfnNameBuffer, 0, 261 * sizeof(UCHAR));
645 continue;
646 }
647
648 return FALSE;
649 }
650
651 static BOOLEAN FatXSearchDirectoryBufferForFile(PFAT_VOLUME_INFO Volume, PVOID DirectoryBuffer, ULONG DirectorySize, PCHAR FileName, PFAT_FILE_INFO FatFileInfoPointer)
652 {
653 ULONG EntryCount;
654 ULONG CurrentEntry;
655 SIZE_T FileNameLen;
656 FATX_DIRENTRY OurDirEntry;
657 PFATX_DIRENTRY DirEntry = &OurDirEntry;
658
659 EntryCount = DirectorySize / sizeof(FATX_DIRENTRY);
660
661 TRACE("FatXSearchDirectoryBufferForFile() DirectoryBuffer = 0x%x EntryCount = %d FileName = %s\n", DirectoryBuffer, EntryCount, FileName);
662
663 FileNameLen = strlen(FileName);
664
665 for (CurrentEntry = 0; CurrentEntry < EntryCount; CurrentEntry++, DirectoryBuffer = ((PFATX_DIRENTRY)DirectoryBuffer)+1)
666 {
667 OurDirEntry = *(PFATX_DIRENTRY) DirectoryBuffer;
668 FatSwapFatXDirEntry(&OurDirEntry);
669 if (0xff == DirEntry->FileNameSize)
670 {
671 break;
672 }
673 if (0xe5 == DirEntry->FileNameSize)
674 {
675 continue;
676 }
677 if (FileNameLen == DirEntry->FileNameSize &&
678 0 == _strnicmp(FileName, DirEntry->FileName, FileNameLen))
679 {
680 /*
681 * We found the entry, now fill in the FAT_FILE_INFO struct
682 */
683 FatFileInfoPointer->FileSize = DirEntry->Size;
684 FatFileInfoPointer->FilePointer = 0;
685
686 TRACE("FATX Directory Entry:\n");
687 TRACE("FileNameSize = %d\n", DirEntry->FileNameSize);
688 TRACE("Attr = 0x%x\n", DirEntry->Attr);
689 TRACE("StartCluster = 0x%x\n", DirEntry->StartCluster);
690 TRACE("Size = %d\n", DirEntry->Size);
691 TRACE("Time = %d\n", DirEntry->Time);
692 TRACE("Date = %d\n", DirEntry->Date);
693 TRACE("CreateTime = %d\n", DirEntry->CreateTime);
694 TRACE("CreateDate = %d\n", DirEntry->CreateDate);
695 TRACE("LastAccessTime = %d\n", DirEntry->LastAccessTime);
696 TRACE("LastAccessDate = %d\n", DirEntry->LastAccessDate);
697
698 /*
699 * Get the cluster chain
700 */
701 FatFileInfoPointer->FileFatChain = FatGetClusterChainArray(Volume, DirEntry->StartCluster);
702
703 /*
704 * See if memory allocation failed
705 */
706 if (NULL == FatFileInfoPointer->FileFatChain)
707 {
708 return FALSE;
709 }
710
711 return TRUE;
712 }
713 }
714
715 return FALSE;
716 }
717
718 /*
719 * FatLookupFile()
720 * This function searches the file system for the
721 * specified filename and fills in an FAT_FILE_INFO structure
722 * with info describing the file, etc. returns ARC error code
723 */
724 LONG FatLookupFile(PFAT_VOLUME_INFO Volume, PCSTR FileName, ULONG DeviceId, PFAT_FILE_INFO FatFileInfoPointer)
725 {
726 UINT32 i;
727 ULONG NumberOfPathParts;
728 CHAR PathPart[261];
729 PVOID DirectoryBuffer;
730 ULONG DirectoryStartCluster = 0;
731 ULONG DirectorySize;
732 FAT_FILE_INFO FatFileInfo;
733
734 TRACE("FatLookupFile() FileName = %s\n", FileName);
735
736 memset(FatFileInfoPointer, 0, sizeof(FAT_FILE_INFO));
737
738 //
739 // Figure out how many sub-directories we are nested in
740 //
741 NumberOfPathParts = FsGetNumPathParts(FileName);
742
743 //
744 // Loop once for each part
745 //
746 for (i=0; i<NumberOfPathParts; i++)
747 {
748 //
749 // Get first path part
750 //
751 FsGetFirstNameFromPath(PathPart, FileName);
752
753 //
754 // Advance to the next part of the path
755 //
756 for (; (*FileName != '\\') && (*FileName != '/') && (*FileName != '\0'); FileName++)
757 {
758 }
759 FileName++;
760
761 //
762 // Buffer the directory contents
763 //
764 DirectoryBuffer = FatBufferDirectory(Volume, DirectoryStartCluster, &DirectorySize, (i == 0) );
765 if (DirectoryBuffer == NULL)
766 {
767 return ENOMEM;
768 }
769
770 //
771 // Search for file name in directory
772 //
773 if (ISFATX(Volume->FatType))
774 {
775 if (!FatXSearchDirectoryBufferForFile(Volume, DirectoryBuffer, DirectorySize, PathPart, &FatFileInfo))
776 {
777 MmFreeMemory(DirectoryBuffer);
778 return ENOENT;
779 }
780 }
781 else
782 {
783 if (!FatSearchDirectoryBufferForFile(Volume, DirectoryBuffer, DirectorySize, PathPart, &FatFileInfo))
784 {
785 MmFreeMemory(DirectoryBuffer);
786 return ENOENT;
787 }
788 }
789
790 MmFreeMemory(DirectoryBuffer);
791
792 //
793 // If we have another sub-directory to go then
794 // grab the start cluster and free the fat chain array
795 //
796 if ((i+1) < NumberOfPathParts)
797 {
798 //
799 // Check if current entry is a directory
800 //
801 if (!(FatFileInfo.Attributes & ATTR_DIRECTORY))
802 {
803 MmFreeMemory(FatFileInfo.FileFatChain);
804 return ENOTDIR;
805 }
806 DirectoryStartCluster = FatFileInfo.FileFatChain[0];
807 }
808 MmFreeMemory(FatFileInfo.FileFatChain);
809 }
810
811 memcpy(FatFileInfoPointer, &FatFileInfo, sizeof(FAT_FILE_INFO));
812
813 return ESUCCESS;
814 }
815
816 /*
817 * FatParseFileName()
818 * This function parses a directory entry name which
819 * is in the form of "FILE EXT" and puts it in Buffer
820 * in the form of "file.ext"
821 */
822 void FatParseShortFileName(PCHAR Buffer, PDIRENTRY DirEntry)
823 {
824 ULONG Idx;
825
826 Idx = 0;
827 RtlZeroMemory(Buffer, 13);
828
829 //
830 // Fixup first character
831 //
832 if (DirEntry->FileName[0] == 0x05)
833 {
834 DirEntry->FileName[0] = 0xE5;
835 }
836
837 //
838 // Get the file name
839 //
840 while (Idx < 8)
841 {
842 if (DirEntry->FileName[Idx] == ' ')
843 {
844 break;
845 }
846
847 Buffer[Idx] = DirEntry->FileName[Idx];
848 Idx++;
849 }
850
851 //
852 // Get extension
853 //
854 if ((DirEntry->FileName[8] != ' '))
855 {
856 Buffer[Idx++] = '.';
857 Buffer[Idx++] = (DirEntry->FileName[8] == ' ') ? '\0' : DirEntry->FileName[8];
858 Buffer[Idx++] = (DirEntry->FileName[9] == ' ') ? '\0' : DirEntry->FileName[9];
859 Buffer[Idx++] = (DirEntry->FileName[10] == ' ') ? '\0' : DirEntry->FileName[10];
860 }
861
862 //TRACE("FatParseShortFileName() ShortName = %s\n", Buffer);
863 }
864
865 /*
866 * FatGetFatEntry()
867 * returns the Fat entry for a given cluster number
868 */
869 BOOLEAN FatGetFatEntry(PFAT_VOLUME_INFO Volume, ULONG Cluster, ULONG* ClusterPointer)
870 {
871 ULONG fat = 0;
872 UINT32 FatOffset;
873 UINT32 ThisFatSecNum;
874 UINT32 ThisFatEntOffset;
875
876 //TRACE("FatGetFatEntry() Retrieving FAT entry for cluster %d.\n", Cluster);
877
878 switch(Volume->FatType)
879 {
880 case FAT12:
881
882 FatOffset = Cluster + (Cluster / 2);
883 ThisFatSecNum = Volume->ActiveFatSectorStart + (FatOffset / Volume->BytesPerSector);
884 ThisFatEntOffset = (FatOffset % Volume->BytesPerSector);
885
886 TRACE("FatOffset: %d\n", FatOffset);
887 TRACE("ThisFatSecNum: %d\n", ThisFatSecNum);
888 TRACE("ThisFatEntOffset: %d\n", ThisFatEntOffset);
889
890 if (ThisFatEntOffset == (Volume->BytesPerSector - 1))
891 {
892 if (!FatReadVolumeSectors(Volume, ThisFatSecNum, 2, (PVOID)FILESYSBUFFER))
893 {
894 return FALSE;
895 }
896 }
897 else
898 {
899 if (!FatReadVolumeSectors(Volume, ThisFatSecNum, 1, (PVOID)FILESYSBUFFER))
900 {
901 return FALSE;
902 }
903 }
904
905 fat = *((USHORT *) ((ULONG_PTR)FILESYSBUFFER + ThisFatEntOffset));
906 fat = SWAPW(fat);
907 if (Cluster & 0x0001)
908 fat = fat >> 4; /* Cluster number is ODD */
909 else
910 fat = fat & 0x0FFF; /* Cluster number is EVEN */
911
912 break;
913
914 case FAT16:
915 case FATX16:
916
917 FatOffset = (Cluster * 2);
918 ThisFatSecNum = Volume->ActiveFatSectorStart + (FatOffset / Volume->BytesPerSector);
919 ThisFatEntOffset = (FatOffset % Volume->BytesPerSector);
920
921 if (!FatReadVolumeSectors(Volume, ThisFatSecNum, 1, (PVOID)FILESYSBUFFER))
922 {
923 return FALSE;
924 }
925
926 fat = *((USHORT *) ((ULONG_PTR)FILESYSBUFFER + ThisFatEntOffset));
927 fat = SWAPW(fat);
928
929 break;
930
931 case FAT32:
932 case FATX32:
933
934 FatOffset = (Cluster * 4);
935 ThisFatSecNum = Volume->ActiveFatSectorStart + (FatOffset / Volume->BytesPerSector);
936 ThisFatEntOffset = (FatOffset % Volume->BytesPerSector);
937
938 if (!FatReadVolumeSectors(Volume, ThisFatSecNum, 1, (PVOID)FILESYSBUFFER))
939 {
940 return FALSE;
941 }
942
943 // Get the fat entry
944 fat = (*((ULONG *) ((ULONG_PTR)FILESYSBUFFER + ThisFatEntOffset))) & 0x0FFFFFFF;
945 fat = SWAPD(fat);
946
947 break;
948
949 default:
950 TRACE("Unknown FAT type %d\n", Volume->FatType);
951 return FALSE;
952
953 }
954
955 //TRACE("FAT entry is 0x%x.\n", fat);
956
957 *ClusterPointer = fat;
958
959 return TRUE;
960 }
961
962 ULONG FatCountClustersInChain(PFAT_VOLUME_INFO Volume, ULONG StartCluster)
963 {
964 ULONG ClusterCount = 0;
965
966 TRACE("FatCountClustersInChain() StartCluster = %d\n", StartCluster);
967
968 while (1)
969 {
970 //
971 // If end of chain then break out of our cluster counting loop
972 //
973 if (((Volume->FatType == FAT12) && (StartCluster >= 0xff8)) ||
974 ((Volume->FatType == FAT16 || Volume->FatType == FATX16) && (StartCluster >= 0xfff8)) ||
975 ((Volume->FatType == FAT32 || Volume->FatType == FATX32) && (StartCluster >= 0x0ffffff8)))
976 {
977 break;
978 }
979
980 //
981 // Increment count
982 //
983 ClusterCount++;
984
985 //
986 // Get next cluster
987 //
988 if (!FatGetFatEntry(Volume, StartCluster, &StartCluster))
989 {
990 return 0;
991 }
992 }
993
994 TRACE("FatCountClustersInChain() ClusterCount = %d\n", ClusterCount);
995
996 return ClusterCount;
997 }
998
999 ULONG* FatGetClusterChainArray(PFAT_VOLUME_INFO Volume, ULONG StartCluster)
1000 {
1001 ULONG ClusterCount;
1002 ULONG ArraySize;
1003 ULONG* ArrayPointer;
1004 ULONG Idx;
1005
1006 TRACE("FatGetClusterChainArray() StartCluster = %d\n", StartCluster);
1007
1008 ClusterCount = FatCountClustersInChain(Volume, StartCluster) + 1; // Lets get the 0x0ffffff8 on the end of the array
1009 ArraySize = ClusterCount * sizeof(ULONG);
1010
1011 //
1012 // Allocate array memory
1013 //
1014 ArrayPointer = MmAllocateMemory(ArraySize);
1015
1016 if (ArrayPointer == NULL)
1017 {
1018 return NULL;
1019 }
1020
1021 //
1022 // Loop through and set array values
1023 //
1024 for (Idx=0; Idx<ClusterCount; Idx++)
1025 {
1026 //
1027 // Set current cluster
1028 //
1029 ArrayPointer[Idx] = StartCluster;
1030
1031 //
1032 // Don't try to get next cluster for last cluster
1033 //
1034 if (((Volume->FatType == FAT12) && (StartCluster >= 0xff8)) ||
1035 ((Volume->FatType == FAT16 || Volume->FatType == FATX16) && (StartCluster >= 0xfff8)) ||
1036 ((Volume->FatType == FAT32 || Volume->FatType == FATX32) && (StartCluster >= 0x0ffffff8)))
1037 {
1038 Idx++;
1039 break;
1040 }
1041
1042 //
1043 // Get next cluster
1044 //
1045 if (!FatGetFatEntry(Volume, StartCluster, &StartCluster))
1046 {
1047 MmFreeMemory(ArrayPointer);
1048 return NULL;
1049 }
1050 }
1051
1052 return ArrayPointer;
1053 }
1054
1055 /*
1056 * FatReadClusterChain()
1057 * Reads the specified clusters into memory
1058 */
1059 BOOLEAN FatReadClusterChain(PFAT_VOLUME_INFO Volume, ULONG StartClusterNumber, ULONG NumberOfClusters, PVOID Buffer)
1060 {
1061 ULONG ClusterStartSector;
1062
1063 TRACE("FatReadClusterChain() StartClusterNumber = %d NumberOfClusters = %d Buffer = 0x%x\n", StartClusterNumber, NumberOfClusters, Buffer);
1064
1065 while (NumberOfClusters > 0)
1066 {
1067
1068 //TRACE("FatReadClusterChain() StartClusterNumber = %d NumberOfClusters = %d Buffer = 0x%x\n", StartClusterNumber, NumberOfClusters, Buffer);
1069 //
1070 // Calculate starting sector for cluster
1071 //
1072 ClusterStartSector = ((StartClusterNumber - 2) * Volume->SectorsPerCluster) + Volume->DataSectorStart;
1073
1074 //
1075 // Read cluster into memory
1076 //
1077 if (!FatReadVolumeSectors(Volume, ClusterStartSector, Volume->SectorsPerCluster, (PVOID)FILESYSBUFFER))
1078 {
1079 return FALSE;
1080 }
1081
1082 memcpy(Buffer, (PVOID)FILESYSBUFFER, Volume->SectorsPerCluster * Volume->BytesPerSector);
1083
1084 //
1085 // Decrement count of clusters left to read
1086 //
1087 NumberOfClusters--;
1088
1089 //
1090 // Increment buffer address by cluster size
1091 //
1092 Buffer = (PVOID)((ULONG_PTR)Buffer + (Volume->SectorsPerCluster * Volume->BytesPerSector));
1093
1094 //
1095 // Get next cluster
1096 //
1097 if (!FatGetFatEntry(Volume, StartClusterNumber, &StartClusterNumber))
1098 {
1099 return FALSE;
1100 }
1101
1102 //
1103 // If end of chain then break out of our cluster reading loop
1104 //
1105 if (((Volume->FatType == FAT12) && (StartClusterNumber >= 0xff8)) ||
1106 ((Volume->FatType == FAT16 || Volume->FatType == FATX16) && (StartClusterNumber >= 0xfff8)) ||
1107 ((Volume->FatType == FAT32 || Volume->FatType == FATX32) && (StartClusterNumber >= 0x0ffffff8)))
1108 {
1109 break;
1110 }
1111 }
1112
1113 return TRUE;
1114 }
1115
1116 /*
1117 * FatReadPartialCluster()
1118 * Reads part of a cluster into memory
1119 */
1120 BOOLEAN FatReadPartialCluster(PFAT_VOLUME_INFO Volume, ULONG ClusterNumber, ULONG StartingOffset, ULONG Length, PVOID Buffer)
1121 {
1122 ULONG ClusterStartSector;
1123
1124 //TRACE("FatReadPartialCluster() ClusterNumber = %d StartingOffset = %d Length = %d Buffer = 0x%x\n", ClusterNumber, StartingOffset, Length, Buffer);
1125
1126 ClusterStartSector = ((ClusterNumber - 2) * Volume->SectorsPerCluster) + Volume->DataSectorStart;
1127
1128 if (!FatReadVolumeSectors(Volume, ClusterStartSector, Volume->SectorsPerCluster, (PVOID)FILESYSBUFFER))
1129 {
1130 return FALSE;
1131 }
1132
1133 memcpy(Buffer, (PVOID)((ULONG_PTR)FILESYSBUFFER + StartingOffset), Length);
1134
1135 return TRUE;
1136 }
1137
1138 /*
1139 * FatReadFile()
1140 * Reads BytesToRead from open file and
1141 * returns the number of bytes read in BytesRead
1142 */
1143 BOOLEAN FatReadFile(PFAT_FILE_INFO FatFileInfo, ULONG BytesToRead, ULONG* BytesRead, PVOID Buffer)
1144 {
1145 PFAT_VOLUME_INFO Volume = FatFileInfo->Volume;
1146 ULONG ClusterNumber;
1147 ULONG OffsetInCluster;
1148 ULONG LengthInCluster;
1149 ULONG NumberOfClusters;
1150 ULONG BytesPerCluster;
1151
1152 TRACE("FatReadFile() BytesToRead = %d Buffer = 0x%x\n", BytesToRead, Buffer);
1153
1154 if (BytesRead != NULL)
1155 {
1156 *BytesRead = 0;
1157 }
1158
1159 //
1160 // If they are trying to read past the
1161 // end of the file then return success
1162 // with BytesRead == 0
1163 //
1164 if (FatFileInfo->FilePointer >= FatFileInfo->FileSize)
1165 {
1166 return TRUE;
1167 }
1168
1169 //
1170 // If they are trying to read more than there is to read
1171 // then adjust the amount to read
1172 //
1173 if ((FatFileInfo->FilePointer + BytesToRead) > FatFileInfo->FileSize)
1174 {
1175 BytesToRead = (FatFileInfo->FileSize - FatFileInfo->FilePointer);
1176 }
1177
1178 //
1179 // Ok, now we have to perform at most 3 calculations
1180 // I'll draw you a picture (using nifty ASCII art):
1181 //
1182 // CurrentFilePointer -+
1183 // |
1184 // +----------------+
1185 // |
1186 // +-----------+-----------+-----------+-----------+
1187 // | Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 |
1188 // +-----------+-----------+-----------+-----------+
1189 // | |
1190 // +---------------+--------------------+
1191 // |
1192 // BytesToRead -------+
1193 //
1194 // 1 - The first calculation (and read) will align
1195 // the file pointer with the next cluster.
1196 // boundary (if we are supposed to read that much)
1197 // 2 - The next calculation (and read) will read
1198 // in all the full clusters that the requested
1199 // amount of data would cover (in this case
1200 // clusters 2 & 3).
1201 // 3 - The last calculation (and read) would read
1202 // in the remainder of the data requested out of
1203 // the last cluster.
1204 //
1205
1206 BytesPerCluster = Volume->SectorsPerCluster * Volume->BytesPerSector;
1207
1208 //
1209 // Only do the first read if we
1210 // aren't aligned on a cluster boundary
1211 //
1212 if (FatFileInfo->FilePointer % BytesPerCluster)
1213 {
1214 //
1215 // Do the math for our first read
1216 //
1217 ClusterNumber = (FatFileInfo->FilePointer / BytesPerCluster);
1218 ClusterNumber = FatFileInfo->FileFatChain[ClusterNumber];
1219 OffsetInCluster = (FatFileInfo->FilePointer % BytesPerCluster);
1220 LengthInCluster = (BytesToRead > (BytesPerCluster - OffsetInCluster)) ? (BytesPerCluster - OffsetInCluster) : BytesToRead;
1221
1222 //
1223 // Now do the read and update BytesRead, BytesToRead, FilePointer, & Buffer
1224 //
1225 if (!FatReadPartialCluster(Volume, ClusterNumber, OffsetInCluster, LengthInCluster, Buffer))
1226 {
1227 return FALSE;
1228 }
1229 if (BytesRead != NULL)
1230 {
1231 *BytesRead += LengthInCluster;
1232 }
1233 BytesToRead -= LengthInCluster;
1234 FatFileInfo->FilePointer += LengthInCluster;
1235 Buffer = (PVOID)((ULONG_PTR)Buffer + LengthInCluster);
1236 }
1237
1238 //
1239 // Do the math for our second read (if any data left)
1240 //
1241 if (BytesToRead > 0)
1242 {
1243 //
1244 // Determine how many full clusters we need to read
1245 //
1246 NumberOfClusters = (BytesToRead / BytesPerCluster);
1247
1248 if (NumberOfClusters > 0)
1249 {
1250 ClusterNumber = (FatFileInfo->FilePointer / BytesPerCluster);
1251 ClusterNumber = FatFileInfo->FileFatChain[ClusterNumber];
1252
1253 //
1254 // Now do the read and update BytesRead, BytesToRead, FilePointer, & Buffer
1255 //
1256 if (!FatReadClusterChain(Volume, ClusterNumber, NumberOfClusters, Buffer))
1257 {
1258 return FALSE;
1259 }
1260 if (BytesRead != NULL)
1261 {
1262 *BytesRead += (NumberOfClusters * BytesPerCluster);
1263 }
1264 BytesToRead -= (NumberOfClusters * BytesPerCluster);
1265 FatFileInfo->FilePointer += (NumberOfClusters * BytesPerCluster);
1266 Buffer = (PVOID)((ULONG_PTR)Buffer + (NumberOfClusters * BytesPerCluster));
1267 }
1268 }
1269
1270 //
1271 // Do the math for our third read (if any data left)
1272 //
1273 if (BytesToRead > 0)
1274 {
1275 ClusterNumber = (FatFileInfo->FilePointer / BytesPerCluster);
1276 ClusterNumber = FatFileInfo->FileFatChain[ClusterNumber];
1277
1278 //
1279 // Now do the read and update BytesRead, BytesToRead, FilePointer, & Buffer
1280 //
1281 if (!FatReadPartialCluster(Volume, ClusterNumber, 0, BytesToRead, Buffer))
1282 {
1283 return FALSE;
1284 }
1285 if (BytesRead != NULL)
1286 {
1287 *BytesRead += BytesToRead;
1288 }
1289 FatFileInfo->FilePointer += BytesToRead;
1290 BytesToRead -= BytesToRead;
1291 Buffer = (PVOID)((ULONG_PTR)Buffer + BytesToRead);
1292 }
1293
1294 return TRUE;
1295 }
1296
1297 BOOLEAN FatReadVolumeSectors(PFAT_VOLUME_INFO Volume, ULONG SectorNumber, ULONG SectorCount, PVOID Buffer)
1298 {
1299 LARGE_INTEGER Position;
1300 ULONG Count;
1301 LONG ret;
1302
1303 //TRACE("FatReadVolumeSectors(): SectorNumber %d, SectorCount %d, Buffer %p\n",
1304 // SectorNumber, SectorCount, Buffer);
1305
1306 //
1307 // Seek to right position
1308 //
1309 Position.QuadPart = SectorNumber * 512;
1310 ret = ArcSeek(Volume->DeviceId, &Position, SeekAbsolute);
1311 if (ret != ESUCCESS)
1312 {
1313 TRACE("FatReadVolumeSectors() Failed to seek\n");
1314 return FALSE;
1315 }
1316
1317 //
1318 // Read data
1319 //
1320 ret = ArcRead(Volume->DeviceId, Buffer, SectorCount * 512, &Count);
1321 if (ret != ESUCCESS || Count != SectorCount * 512)
1322 {
1323 TRACE("FatReadVolumeSectors() Failed to read\n");
1324 return FALSE;
1325 }
1326
1327 // Return success
1328 return TRUE;
1329 }
1330
1331 LONG FatClose(ULONG FileId)
1332 {
1333 PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
1334
1335 MmHeapFree(FileHandle);
1336
1337 return ESUCCESS;
1338 }
1339
1340 LONG FatGetFileInformation(ULONG FileId, FILEINFORMATION* Information)
1341 {
1342 PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
1343
1344 RtlZeroMemory(Information, sizeof(FILEINFORMATION));
1345 Information->EndingAddress.LowPart = FileHandle->FileSize;
1346 Information->CurrentAddress.LowPart = FileHandle->FilePointer;
1347
1348 TRACE("FatGetFileInformation() FileSize = %d\n",
1349 Information->EndingAddress.LowPart);
1350 TRACE("FatGetFileInformation() FilePointer = %d\n",
1351 Information->CurrentAddress.LowPart);
1352
1353 return ESUCCESS;
1354 }
1355
1356 LONG FatOpen(CHAR* Path, OPENMODE OpenMode, ULONG* FileId)
1357 {
1358 PFAT_VOLUME_INFO FatVolume;
1359 FAT_FILE_INFO TempFileInfo;
1360 PFAT_FILE_INFO FileHandle;
1361 ULONG DeviceId;
1362 BOOLEAN IsDirectory;
1363 LONG ret;
1364
1365 if (OpenMode != OpenReadOnly && OpenMode != OpenDirectory)
1366 return EACCES;
1367
1368 DeviceId = FsGetDeviceId(*FileId);
1369 FatVolume = FatVolumes[DeviceId];
1370
1371 TRACE("FatOpen() FileName = %s\n", Path);
1372
1373 RtlZeroMemory(&TempFileInfo, sizeof(TempFileInfo));
1374 ret = FatLookupFile(FatVolume, Path, DeviceId, &TempFileInfo);
1375 if (ret != ESUCCESS)
1376 return ENOENT;
1377
1378 //
1379 // Check if caller opened what he expected (dir vs file)
1380 //
1381 IsDirectory = (TempFileInfo.Attributes & ATTR_DIRECTORY) != 0;
1382 if (IsDirectory && OpenMode != OpenDirectory)
1383 return EISDIR;
1384 else if (!IsDirectory && OpenMode != OpenReadOnly)
1385 return ENOTDIR;
1386
1387 FileHandle = MmHeapAlloc(sizeof(FAT_FILE_INFO));
1388 if (!FileHandle)
1389 return ENOMEM;
1390
1391 RtlCopyMemory(FileHandle, &TempFileInfo, sizeof(FAT_FILE_INFO));
1392 FileHandle->Volume = FatVolume;
1393
1394 FsSetDeviceSpecific(*FileId, FileHandle);
1395 return ESUCCESS;
1396 }
1397
1398 LONG FatRead(ULONG FileId, VOID* Buffer, ULONG N, ULONG* Count)
1399 {
1400 PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
1401 BOOLEAN ret;
1402
1403 //
1404 // Call old read method
1405 //
1406 ret = FatReadFile(FileHandle, N, Count, Buffer);
1407
1408 //
1409 // Check for success
1410 //
1411 if (ret)
1412 return ESUCCESS;
1413 else
1414 return EIO;
1415 }
1416
1417 LONG FatSeek(ULONG FileId, LARGE_INTEGER* Position, SEEKMODE SeekMode)
1418 {
1419 PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
1420
1421 TRACE("FatSeek() NewFilePointer = %lu\n", Position->LowPart);
1422
1423 if (SeekMode != SeekAbsolute)
1424 return EINVAL;
1425 if (Position->HighPart != 0)
1426 return EINVAL;
1427 if (Position->LowPart >= FileHandle->FileSize)
1428 return EINVAL;
1429
1430 FileHandle->FilePointer = Position->LowPart;
1431 return ESUCCESS;
1432 }
1433
1434 const DEVVTBL FatFuncTable =
1435 {
1436 FatClose,
1437 FatGetFileInformation,
1438 FatOpen,
1439 FatRead,
1440 FatSeek,
1441 L"fastfat",
1442 };
1443
1444 const DEVVTBL* FatMount(ULONG DeviceId)
1445 {
1446 PFAT_VOLUME_INFO Volume;
1447 UCHAR Buffer[512];
1448 PFAT_BOOTSECTOR BootSector = (PFAT_BOOTSECTOR)Buffer;
1449 PFAT32_BOOTSECTOR BootSector32 = (PFAT32_BOOTSECTOR)Buffer;
1450 PFATX_BOOTSECTOR BootSectorX = (PFATX_BOOTSECTOR)Buffer;
1451 FILEINFORMATION FileInformation;
1452 LARGE_INTEGER Position;
1453 ULONG Count;
1454 ULARGE_INTEGER SectorCount;
1455 LONG ret;
1456
1457 //
1458 // Allocate data for volume information
1459 //
1460 Volume = MmHeapAlloc(sizeof(FAT_VOLUME_INFO));
1461 if (!Volume)
1462 return NULL;
1463 RtlZeroMemory(Volume, sizeof(FAT_VOLUME_INFO));
1464
1465 //
1466 // Read the BootSector
1467 //
1468 Position.HighPart = 0;
1469 Position.LowPart = 0;
1470 ret = ArcSeek(DeviceId, &Position, SeekAbsolute);
1471 if (ret != ESUCCESS)
1472 {
1473 MmHeapFree(Volume);
1474 return NULL;
1475 }
1476 ret = ArcRead(DeviceId, Buffer, sizeof(Buffer), &Count);
1477 if (ret != ESUCCESS || Count != sizeof(Buffer))
1478 {
1479 MmHeapFree(Volume);
1480 return NULL;
1481 }
1482
1483 //
1484 // Check if BootSector is valid. If no, return early
1485 //
1486 if (!RtlEqualMemory(BootSector->FileSystemType, "FAT12 ", 8) &&
1487 !RtlEqualMemory(BootSector->FileSystemType, "FAT16 ", 8) &&
1488 !RtlEqualMemory(BootSector32->FileSystemType, "FAT32 ", 8) &&
1489 !RtlEqualMemory(BootSectorX->FileSystemType, "FATX", 4))
1490 {
1491 MmHeapFree(Volume);
1492 return NULL;
1493 }
1494
1495 //
1496 // Determine sector count
1497 //
1498 ret = ArcGetFileInformation(DeviceId, &FileInformation);
1499 if (ret != ESUCCESS)
1500 {
1501 MmHeapFree(Volume);
1502 return NULL;
1503 }
1504 SectorCount.HighPart = FileInformation.EndingAddress.HighPart;
1505 SectorCount.LowPart = FileInformation.EndingAddress.LowPart;
1506 SectorCount.QuadPart /= SECTOR_SIZE;
1507
1508 //
1509 // Keep device id
1510 //
1511 Volume->DeviceId = DeviceId;
1512
1513 //
1514 // Really open the volume
1515 //
1516 if (!FatOpenVolume(Volume, BootSector, SectorCount.QuadPart))
1517 {
1518 MmHeapFree(Volume);
1519 return NULL;
1520 }
1521
1522 //
1523 // Remember FAT volume information
1524 //
1525 FatVolumes[DeviceId] = Volume;
1526
1527 //
1528 // Return success
1529 //
1530 return &FatFuncTable;
1531 }
A free Windows-compatible Operating System