aboutsummaryrefslogtreecommitdiff
path: root/sdk-modifications/libsrc/fs/partition.c
blob: 1791b407e12c2bbe7607004d57d82367cd313e48 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
/*
 partition.c
 Functions for mounting and dismounting partitions
 on various block devices.

 Copyright (c) 2006 Michael "Chishm" Chisholm
	
 Redistribution and use in source and binary forms, with or without modification,
 are permitted provided that the following conditions are met:

  1. Redistributions of source code must retain the above copyright notice,
     this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright notice,
     this list of conditions and the following disclaimer in the documentation and/or
     other materials provided with the distribution.
  3. The name of the author may not be used to endorse or promote products derived
     from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	2006-07-11 - Chishm
		* Original release

	2006-08-10 - Chishm
		* Fixed problem when openning files starting with "fat"
		
	2006-10-28 - Chishm
		* _partitions changed to _FAT_partitions to maintain the same style of naming as the functions
*/
//version 1.1
//Note: fix bug in _FAT_partition_setDefaultPartition() function

#include "partition.h"
#include "bit_ops.h"
#include "file_allocation_table.h"
#include "directory.h"

#include <string.h>
#include <ctype.h>

#include "mem_allocate.h"

/* 
This device name, as known by DevKitPro
*/
const char* DEVICE_NAME = "fat";

/*
Data offsets
*/

// BIOS Parameter Block offsets
enum BPB {
	BPB_jmpBoot = 0x00,
	BPB_OEMName = 0x03,
	// BIOS Parameter Block
	BPB_bytesPerSector = 0x0B,
	BPB_sectorsPerCluster = 0x0D,
	BPB_reservedSectors = 0x0E,
	BPB_numFATs = 0x10,
	BPB_rootEntries = 0x11,
	BPB_numSectorsSmall = 0x13,
	BPB_mediaDesc = 0x15,
	BPB_sectorsPerFAT = 0x16,
	BPB_sectorsPerTrk = 0x18,
	BPB_numHeads = 0x1A,
	BPB_numHiddenSectors = 0x1C,
	BPB_numSectors = 0x20,
	// Ext BIOS Parameter Block for FAT16
	BPB_FAT16_driveNumber = 0x24,
	BPB_FAT16_reserved1 = 0x25,
	BPB_FAT16_extBootSig = 0x26,
	BPB_FAT16_volumeID = 0x27,
	BPB_FAT16_volumeLabel = 0x2B,
	BPB_FAT16_fileSysType = 0x36,
	// Bootcode
	BPB_FAT16_bootCode = 0x3E,
	// FAT32 extended block
	BPB_FAT32_sectorsPerFAT32 = 0x24,
	BPB_FAT32_extFlags = 0x28,
	BPB_FAT32_fsVer = 0x2A,
	BPB_FAT32_rootClus = 0x2C,
	BPB_FAT32_fsInfo = 0x30,
	BPB_FAT32_bkBootSec = 0x32,
	// Ext BIOS Parameter Block for FAT32
	BPB_FAT32_driveNumber = 0x40,
	BPB_FAT32_reserved1 = 0x41,
	BPB_FAT32_extBootSig = 0x42,
	BPB_FAT32_volumeID = 0x43,
	BPB_FAT32_volumeLabel = 0x47,
	BPB_FAT32_fileSysType = 0x52,
	// Bootcode
	BPB_FAT32_bootCode = 0x5A,
	BPB_bootSig_55 = 0x1FE,
	BPB_bootSig_AA = 0x1FF
};


#ifdef NDS
#define MAXIMUM_PARTITIONS 4
PARTITION* _FAT_partitions[MAXIMUM_PARTITIONS] = {NULL};
#else // not defined NDS
#define MAXIMUM_PARTITIONS 1
PARTITION* _FAT_partitions[MAXIMUM_PARTITIONS] = {NULL};
#endif // defined NDS

// Use a single static buffer for the partitions


static PARTITION* _FAT_partition_constructor ( const IO_INTERFACE* disc, u32 cacheSize) {
	PARTITION* partition;
	int i;
	u32 bootSector;
	u8 sectorBuffer[BYTES_PER_READ] = {0};

	// Read first sector of disc
	if ( !_FAT_disc_readSectors (disc, 0, 1, sectorBuffer)) {
		return NULL;
	}

	// Make sure it is a valid MBR or boot sector
	if ( (sectorBuffer[BPB_bootSig_55] != 0x55) || (sectorBuffer[BPB_bootSig_AA] != 0xAA)) {
		return NULL;
	}

	// Check if there is a FAT string, which indicates this is a boot sector
	if ((sectorBuffer[0x36] == 'F') && (sectorBuffer[0x37] == 'A') && (sectorBuffer[0x38] == 'T')) {
		bootSector = 0;
	} else if ((sectorBuffer[0x52] == 'F') && (sectorBuffer[0x53] == 'A') && (sectorBuffer[0x54] == 'T')) {
		// Check for FAT32
		bootSector = 0;
	} else {
		// This is an MBR
		// Find first valid partition from MBR
		// First check for an active partition
		for (i=0x1BE; (i < 0x1FE) && (sectorBuffer[i] != 0x80); i+= 0x10);
		// If it didn't find an active partition, search for any valid partition
		if (i == 0x1FE) {
			for (i=0x1BE; (i < 0x1FE) && (sectorBuffer[i+0x04] == 0x00); i+= 0x10);
		}
		
		// Go to first valid partition
		if ( i != 0x1FE) {
			// Make sure it found a partition
			bootSector = u8array_to_u32(sectorBuffer, 0x8 + i);
		} else {
			bootSector = 0;	// No partition found, assume this is a MBR free disk
		}
	}

	// Read in boot sector
	if ( !_FAT_disc_readSectors (disc, bootSector, 1, sectorBuffer)) {
		return NULL;
	}

	partition = (PARTITION*) _FAT_mem_allocate (sizeof(PARTITION));
	if (partition == NULL) {
		return NULL;
	}

	// Set partition's disc interface
	partition->disc = disc;

	// Store required information about the file system
	partition->fat.sectorsPerFat = u8array_to_u16(sectorBuffer, BPB_sectorsPerFAT);
	if (partition->fat.sectorsPerFat == 0) {
		partition->fat.sectorsPerFat = u8array_to_u32( sectorBuffer, BPB_FAT32_sectorsPerFAT32); 
	}

	partition->numberOfSectors = u8array_to_u16( sectorBuffer, BPB_numSectorsSmall); 
	if (partition->numberOfSectors == 0) {
		partition->numberOfSectors = u8array_to_u32( sectorBuffer, BPB_numSectors);	
	}

	partition->bytesPerSector = BYTES_PER_READ;	// Sector size is redefined to be 512 bytes
	partition->sectorsPerCluster = sectorBuffer[BPB_sectorsPerCluster] * u8array_to_u16(sectorBuffer, BPB_bytesPerSector) / BYTES_PER_READ;
	partition->bytesPerCluster = partition->bytesPerSector * partition->sectorsPerCluster;
	partition->fat.fatStart = bootSector + u8array_to_u16(sectorBuffer, BPB_reservedSectors); 

	partition->rootDirStart = partition->fat.fatStart + (sectorBuffer[BPB_numFATs] * partition->fat.sectorsPerFat);
	partition->dataStart = partition->rootDirStart + (( u8array_to_u16(sectorBuffer, BPB_rootEntries) * DIR_ENTRY_DATA_SIZE) / partition->bytesPerSector);

	partition->totalSize = (partition->numberOfSectors - partition->dataStart) * partition->bytesPerSector;

	// Store info about FAT
	partition->fat.lastCluster = (partition->numberOfSectors - partition->dataStart) / partition->sectorsPerCluster;
	partition->fat.firstFree = CLUSTER_FIRST;

	if (partition->fat.lastCluster < CLUSTERS_PER_FAT12) {
		partition->filesysType = FS_FAT12;	// FAT12 volume
	} else if (partition->fat.lastCluster < CLUSTERS_PER_FAT16) {
		partition->filesysType = FS_FAT16;	// FAT16 volume
	} else {
		partition->filesysType = FS_FAT32;	// FAT32 volume
	}

	if (partition->filesysType != FS_FAT32) {
		partition->rootDirCluster = FAT16_ROOT_DIR_CLUSTER;
	} else {
		// Set up for the FAT32 way
		partition->rootDirCluster = u8array_to_u32(sectorBuffer, BPB_FAT32_rootClus); 
		// Check if FAT mirroring is enabled
		if (!(sectorBuffer[BPB_FAT32_extFlags] & 0x80)) {
			// Use the active FAT
			partition->fat.fatStart = partition->fat.fatStart + ( partition->fat.sectorsPerFat * (sectorBuffer[BPB_FAT32_extFlags] & 0x0F));
		}
	}

	// Create a cache to use
	partition->cache = _FAT_cache_constructor (cacheSize, partition->disc);

	// Set current directory to the root
	partition->cwdCluster = partition->rootDirCluster;
	
	// Check if this disc is writable, and set the readOnly property appropriately
	partition->readOnly = !(_FAT_disc_features(disc) & FEATURE_MEDIUM_CANWRITE);
	
	// There are currently no open files on this partition
	partition->openFileCount = 0;

	return partition;
}

static void _FAT_partition_destructor (PARTITION* partition) {
	_FAT_cache_destructor (partition->cache);
	_FAT_disc_shutdown (partition->disc);
	_FAT_mem_free (partition);
}

bool _FAT_partition_mount (PARTITION_INTERFACE partitionNumber, u32 cacheSize) 
{
#ifdef NDS
	int i;
	const IO_INTERFACE* disc = NULL;
	
	if (_FAT_partitions[partitionNumber] != NULL) {
		return false;
	}	

	switch (partitionNumber) {
		case PI_SLOT_1:
			// Mount the disc in slot 1
			disc = _FAT_disc_dsSlotFindInterface ();
			break;
		case PI_SLOT_2:
			// Mount the disc in slot 2
			disc = _FAT_disc_gbaSlotFindInterface ();
			break;
		case PI_DEFAULT:
		case PI_CUSTOM:
		default:
			// Anything else has to be handled specially
			return false;
			break;
	}

	if (disc == NULL) {
		return false;
	}
	
	// See if that disc is already in use, if so, then just copy the partition pointer
	for (i = 0; i < MAXIMUM_PARTITIONS; i++) {
		if ((_FAT_partitions[i] != NULL) && (_FAT_partitions[i]->disc == disc)) {
			_FAT_partitions[partitionNumber] = _FAT_partitions[i];
			return true;
		}
	}

	_FAT_partitions[partitionNumber] = _FAT_partition_constructor (disc, cacheSize);

	if (_FAT_partitions[partitionNumber] == NULL) {
		return false;
	}

#else // not defined NDS
	const IO_INTERFACE* disc = NULL;
	
	if (_FAT_partitions[partitionNumber] != NULL) {
		return false;
	}	

	// Only ever one partition on GBA
	disc = _FAT_disc_gbaSlotFindInterface ();
	_FAT_partitions[partitionNumber] = _FAT_partition_constructor (disc, cacheSize);
	
#endif // defined NDS

	return true;
}

bool _FAT_partition_mountCustomInterface (const IO_INTERFACE* device, u32 cacheSize) {
#ifdef NDS	
	int i;
	
	if (_FAT_partitions[PI_CUSTOM] != NULL) {
		return false;
	}	

	if (device == NULL) {
		return false;
	}

	// See if that disc is already in use, if so, then just copy the partition pointer
	for (i = 0; i < MAXIMUM_PARTITIONS; i++) {
		if ((_FAT_partitions[i] != NULL) && (_FAT_partitions[i]->disc == device)) {
			_FAT_partitions[PI_CUSTOM] = _FAT_partitions[i];
			return true;
		}
	}

	_FAT_partitions[PI_CUSTOM] = _FAT_partition_constructor (device, cacheSize);

	if (_FAT_partitions[PI_CUSTOM] == NULL) {
		return false;
	}
	
#else // not defined NDS
	if (_FAT_partitions[PI_CART_SLOT] != NULL) {
		return false;
	}	

	if (device == NULL) {
		return false;
	}

	// Only ever one partition on GBA
	_FAT_partitions[PI_CART_SLOT] = _FAT_partition_constructor (device, cacheSize);
	
#endif // defined NDS

	return true;
}

bool _FAT_partition_setDefaultInterface (PARTITION_INTERFACE partitionNumber) 
{
#ifdef NDS	// Can only set the default partition when there is more than 1, so doesn't apply to GBA
	if ((partitionNumber < 1) || (partitionNumber >= MAXIMUM_PARTITIONS)) {
		return false;
	}
	
	if (_FAT_partitions[partitionNumber] == NULL) {
		return false;
	}
	
	_FAT_partitions[PI_DEFAULT] = _FAT_partitions[partitionNumber];
#endif	
	return true;
}

bool _FAT_partition_setDefaultPartition (PARTITION* partition) {
#ifdef NDS	// Can only set the default partition when there is more than 1, so doesn't apply to GBA
	int i;
	
	if (partition == NULL) {
		return false;
	}

	if(_FAT_partitions[PI_DEFAULT] == partition)	//Already is the default partition
		return true;

	// Ensure that this device is already in the list
	for (i = 1; i < MAXIMUM_PARTITIONS; i++) {
		if (_FAT_partitions[i] == partition) {
			break;
		}
	}
	
	// It wasn't in the list, so fail
	if (i == MAXIMUM_PARTITIONS) {
		return false;
	}

	// Change the default partition / device to this one
	_FAT_partitions[PI_DEFAULT] = partition;
	
#endif
	return true;
}

bool _FAT_partition_unmount (PARTITION_INTERFACE partitionNumber) {
	int i;
	PARTITION* partition = _FAT_partitions[partitionNumber];
	
	if (partition == NULL) {
		return false;
	}
	
	if (partition->openFileCount > 0) {
		// There are still open files that need closing
		return false;
	}
	
	// Remove all references to this partition
	for (i = 0; i < MAXIMUM_PARTITIONS; i++) {
		if (_FAT_partitions[i] == partition) {
			_FAT_partitions[i] = NULL;
		}
	}
	
	_FAT_partition_destructor (partition);
	return true;
}

bool _FAT_partition_unsafeUnmount (PARTITION_INTERFACE partitionNumber) {
	int i;
	PARTITION* partition = _FAT_partitions[partitionNumber];
	
	if (partition == NULL) {
		return false;
	}
	
	// Remove all references to this partition
	for (i = 0; i < MAXIMUM_PARTITIONS; i++) {
		if (_FAT_partitions[i] == partition) {
			_FAT_partitions[i] = NULL;
		}
	}
	
	_FAT_cache_invalidate (partition->cache);
	_FAT_partition_destructor (partition);
	return true;
}

PARTITION* _FAT_partition_getPartitionFromPath (const char* path) {
#ifdef NDS
	int namelen;
	int partitionNumber;
	
	// Device name extraction code taken from DevKitPro
	namelen = strlen(DEVICE_NAME);
	if (strchr (path, ':') == NULL) {
		// No device specified
		partitionNumber = PI_DEFAULT;
	} else if( strncmp(DEVICE_NAME, path, namelen) == 0 ) {
		if ( path[namelen] == ':' ) {
			// Only the device name is specified
			partitionNumber = PI_DEFAULT;
		} else if (isdigit(path[namelen]) && path[namelen+1] ==':' ) {
			// Device name and number specified
			partitionNumber = path[namelen] - '0';
		} else {
			// Incorrect device name
			return NULL;
		}
	} else {
		// Incorrect device name
		return NULL;
	}

	if ((partitionNumber < 0) || (partitionNumber >= MAXIMUM_PARTITIONS)) {
		return NULL;
	}

	return _FAT_partitions[partitionNumber];
#else // not defined NDS
	// Only one possible partition on GBA
	return _FAT_partitions[PI_CART_SLOT];
#endif // defined NDS
}

bool _FAT_partition_freeMount( int partitionNumber, const IO_INTERFACE* device, u32 cacheSize) {
	
	if( partitionNumber < 0 || partitionNumber > 3 )
		return false;
	int i;

	if (device == NULL) {
		return false;
	}

	if (_FAT_partitions[partitionNumber] != NULL) {
		if(_FAT_partitions[partitionNumber] -> disc == device)
			return true;

		return false;
	}

	// See if that disc is already in use, if so, then just copy the partition pointer
	for (i = 0; i < MAXIMUM_PARTITIONS; i++) {
		if ((_FAT_partitions[i] != NULL) && (_FAT_partitions[i]->disc == device)) {
			_FAT_partitions[partitionNumber] = _FAT_partitions[i];
			return true;
		}
	}

	_FAT_partitions[partitionNumber] = _FAT_partition_constructor (device, cacheSize);

	if (_FAT_partitions[partitionNumber] == NULL) {
		return false;
	}

	return true;
}