summaryrefslogtreecommitdiff
path: root/fs/fat/fat.c
blob: daa70349d27a786f23140e67808f51f95ce5155a (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
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
/*
 * fat.c
 *
 * R/O (V)FAT 12/16/32 filesystem implementation by Marcus Sundberg
 *
 * 2002-07-28 - rjones@nexus-tech.net - ported to ppcboot v1.1.6
 * 2003-03-10 - kharris@nexus-tech.net - ported to uboot
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>
#include <config.h>
#include <fat.h>
#include <asm/byteorder.h>
#include <part.h>

#if (CONFIG_COMMANDS & CFG_CMD_FAT)

/*
 * Convert a string to lowercase.
 */
static void
downcase(char *str)
{
	while (*str != '\0') {
		TOLOWER(*str);
		str++;
	}
}

static  block_dev_desc_t *cur_dev = NULL;
static unsigned long part_offset = 0;
static int cur_part = 1;

#define DOS_PART_TBL_OFFSET	0x1be
#define DOS_PART_MAGIC_OFFSET	0x1fe
#define DOS_FS_TYPE_OFFSET	0x36

int disk_read (__u32 startblock, __u32 getsize, __u8 * bufptr)
{
	startblock += part_offset;
	if (cur_dev == NULL)
		return -1;
	if (cur_dev->block_read) {
		return cur_dev->block_read (cur_dev->dev, startblock, getsize, (unsigned long *)bufptr);
	}
	return -1;
}


int
fat_register_device(block_dev_desc_t *dev_desc, int part_no)
{
	unsigned char buffer[SECTOR_SIZE];

	if (!dev_desc->block_read)
		return -1;
	cur_dev=dev_desc;
	/* check if we have a MBR (on floppies we have only a PBR) */
	if (dev_desc->block_read (dev_desc->dev, 0, 1, (ulong *) buffer) != 1) {
		printf ("** Can't read from device %d **\n", dev_desc->dev);
		return -1;
	}
	if (buffer[DOS_PART_MAGIC_OFFSET] != 0x55 ||
		buffer[DOS_PART_MAGIC_OFFSET + 1] != 0xaa) {
		/* no signature found */
		return -1;
	}
	if(!strncmp(&buffer[DOS_FS_TYPE_OFFSET],"FAT",3)) {
		/* ok, we assume we are on a PBR only */
		cur_part = 1;
		part_offset=0;
	}
	else {
#if (CONFIG_COMMANDS & CFG_CMD_IDE) || (CONFIG_COMMANDS & CFG_CMD_SCSI)
		disk_partition_t info;
		if(!get_partition_info(dev_desc, part_no, &info)) {
			part_offset = info.start;
			cur_part = part_no;
		}
		else {
			printf ("** Partition %d not valid on device %d **\n",part_no,dev_desc->dev);
			return -1;
		}
#else
		/* FIXME we need to determine the start block of the
		 * partition where the DOS FS resides. This can be done
		 * by using the get_partition_info routine. For this
		 * purpose the libpart must be included.
		 */
		part_offset=32;
		cur_part = 1;
#endif
	}
	return 0;
}


/*
 * Get the first occurence of a directory delimiter ('/' or '\') in a string.
 * Return index into string if found, -1 otherwise.
 */
static int
dirdelim(char *str)
{
	char *start = str;

	while (*str != '\0') {
		if (ISDIRDELIM(*str)) return str - start;
		str++;
	}
	return -1;
}


/*
 * Match volume_info fs_type strings.
 * Return 0 on match, -1 otherwise.
 */
static int
compare_sign(char *str1, char *str2)
{
	char *end = str1+SIGNLEN;

	while (str1 != end) {
		if (*str1 != *str2) {
			return -1;
		}
		str1++;
		str2++;
	}

	return 0;
}


/*
 * Extract zero terminated short name from a directory entry.
 */
static void get_name (dir_entry *dirent, char *s_name)
{
	char *ptr;

	memcpy (s_name, dirent->name, 8);
	s_name[8] = '\0';
	ptr = s_name;
	while (*ptr && *ptr != ' ')
		ptr++;
	if (dirent->ext[0] && dirent->ext[0] != ' ') {
		*ptr = '.';
		ptr++;
		memcpy (ptr, dirent->ext, 3);
		ptr[3] = '\0';
		while (*ptr && *ptr != ' ')
			ptr++;
	}
	*ptr = '\0';
	if (*s_name == DELETED_FLAG)
		*s_name = '\0';
	else if (*s_name == aRING)
		*s_name = 'å';
	downcase (s_name);
}

/*
 * Get the entry at index 'entry' in a FAT (12/16/32) table.
 * On failure 0x00 is returned.
 */
static __u32
get_fatent(fsdata *mydata, __u32 entry)
{
	__u32 bufnum;
	__u32 offset;
	__u32 ret = 0x00;

	switch (mydata->fatsize) {
	case 32:
		bufnum = entry / FAT32BUFSIZE;
		offset = entry - bufnum * FAT32BUFSIZE;
		break;
	case 16:
		bufnum = entry / FAT16BUFSIZE;
		offset = entry - bufnum * FAT16BUFSIZE;
		break;
	case 12:
		bufnum = entry / FAT12BUFSIZE;
		offset = entry - bufnum * FAT12BUFSIZE;
		break;

	default:
		/* Unsupported FAT size */
		return ret;
	}

	/* Read a new block of FAT entries into the cache. */
	if (bufnum != mydata->fatbufnum) {
		int getsize = FATBUFSIZE/FS_BLOCK_SIZE;
		__u8 *bufptr = mydata->fatbuf;
		__u32 fatlength = mydata->fatlength;
		__u32 startblock = bufnum * FATBUFBLOCKS;

		fatlength *= SECTOR_SIZE;	/* We want it in bytes now */
		startblock += mydata->fat_sect;	/* Offset from start of disk */

		if (getsize > fatlength) getsize = fatlength;
		if (disk_read(startblock, getsize, bufptr) < 0) {
			FAT_DPRINT("Error reading FAT blocks\n");
			return ret;
		}
		mydata->fatbufnum = bufnum;
	}

	/* Get the actual entry from the table */
	switch (mydata->fatsize) {
	case 32:
		ret = FAT2CPU32(((__u32*)mydata->fatbuf)[offset]);
		break;
	case 16:
		ret = FAT2CPU16(((__u16*)mydata->fatbuf)[offset]);
		break;
	case 12: {
		__u32 off16 = (offset*3)/4;
		__u16 val1, val2;

		switch (offset & 0x3) {
		case 0:
			ret = FAT2CPU16(((__u16*)mydata->fatbuf)[off16]);
			ret &= 0xfff;
			break;
		case 1:
			val1 = FAT2CPU16(((__u16*)mydata->fatbuf)[off16]);
			val1 &= 0xf000;
			val2 = FAT2CPU16(((__u16*)mydata->fatbuf)[off16+1]);
			val2 &= 0x00ff;
			ret = (val2 << 4) | (val1 >> 12);
			break;
		case 2:
			val1 = FAT2CPU16(((__u16*)mydata->fatbuf)[off16]);
			val1 &= 0xff00;
			val2 = FAT2CPU16(((__u16*)mydata->fatbuf)[off16+1]);
			val2 &= 0x000f;
			ret = (val2 << 8) | (val1 >> 8);
			break;
		case 3:
			ret = FAT2CPU16(((__u16*)mydata->fatbuf)[off16]);;
			ret = (ret & 0xfff0) >> 4;
			break;
		default:
			break;
		}
	}
	break;
	}
	FAT_DPRINT("ret: %d, offset: %d\n", ret, offset);

	return ret;
}


/*
 * Read at most 'size' bytes from the specified cluster into 'buffer'.
 * Return 0 on success, -1 otherwise.
 */
static int
get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
{
	int idx = 0;
	__u32 startsect;

	if (clustnum > 0) {
		startsect = mydata->data_begin + clustnum*mydata->clust_size;
	} else {
		startsect = mydata->rootdir_sect;
	}

	FAT_DPRINT("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
	if (disk_read(startsect, size/FS_BLOCK_SIZE , buffer) < 0) {
		FAT_DPRINT("Error reading data\n");
		return -1;
	}
	if(size % FS_BLOCK_SIZE) {
		__u8 tmpbuf[FS_BLOCK_SIZE];
		idx= size/FS_BLOCK_SIZE;
		if (disk_read(startsect + idx, 1, tmpbuf) < 0) {
			FAT_DPRINT("Error reading data\n");
			return -1;
		}
		buffer += idx*FS_BLOCK_SIZE;

		memcpy(buffer, tmpbuf, size % FS_BLOCK_SIZE);
		return 0;
	}

	return 0;
}


/*
 * Read at most 'maxsize' bytes from the file associated with 'dentptr'
 * into 'buffer'.
 * Return the number of bytes read or -1 on fatal errors.
 */
static long
get_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
	     unsigned long maxsize)
{
	unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
	unsigned int bytesperclust = mydata->clust_size * SECTOR_SIZE;
	__u32 curclust = START(dentptr);
	__u32 endclust, newclust;
	unsigned long actsize;

	FAT_DPRINT("Filesize: %ld bytes\n", filesize);

	if (maxsize > 0 && filesize > maxsize) filesize = maxsize;

	FAT_DPRINT("Reading: %ld bytes\n", filesize);

	actsize=bytesperclust;
	endclust=curclust;
	do {
		/* search for consecutive clusters */
		while(actsize < filesize) {
			newclust = get_fatent(mydata, endclust);
			if((newclust -1)!=endclust)
				goto getit;
			if (newclust <= 0x0001 || newclust >= 0xfff0) {
				FAT_DPRINT("curclust: 0x%x\n", newclust);
				FAT_DPRINT("Invalid FAT entry\n");
				return gotsize;
			}
			endclust=newclust;
			actsize+= bytesperclust;
		}
		/* actsize >= file size */
		actsize -= bytesperclust;
		/* get remaining clusters */
		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
			FAT_ERROR("Error reading cluster\n");
			return -1;
		}
		/* get remaining bytes */
		gotsize += (int)actsize;
		filesize -= actsize;
		buffer += actsize;
		actsize= filesize;
		if (get_cluster(mydata, endclust, buffer, (int)actsize) != 0) {
			FAT_ERROR("Error reading cluster\n");
			return -1;
		}
		gotsize+=actsize;
		return gotsize;
getit:
		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
			FAT_ERROR("Error reading cluster\n");
			return -1;
		}
		gotsize += (int)actsize;
		filesize -= actsize;
		buffer += actsize;
		curclust = get_fatent(mydata, endclust);
		if (curclust <= 0x0001 || curclust >= 0xfff0) {
			FAT_DPRINT("curclust: 0x%x\n", curclust);
			FAT_ERROR("Invalid FAT entry\n");
			return gotsize;
		}
		actsize=bytesperclust;
		endclust=curclust;
	} while (1);
}


#ifdef CONFIG_SUPPORT_VFAT
/*
 * Extract the file name information from 'slotptr' into 'l_name',
 * starting at l_name[*idx].
 * Return 1 if terminator (zero byte) is found, 0 otherwise.
 */
static int
slot2str(dir_slot *slotptr, char *l_name, int *idx)
{
	int j;

	for (j = 0; j <= 8; j += 2) {
		l_name[*idx] = slotptr->name0_4[j];
		if (l_name[*idx] == 0x00) return 1;
		(*idx)++;
	}
	for (j = 0; j <= 10; j += 2) {
		l_name[*idx] = slotptr->name5_10[j];
		if (l_name[*idx] == 0x00) return 1;
		(*idx)++;
	}
	for (j = 0; j <= 2; j += 2) {
		l_name[*idx] = slotptr->name11_12[j];
		if (l_name[*idx] == 0x00) return 1;
		(*idx)++;
	}

	return 0;
}


/*
 * Extract the full long filename starting at 'retdent' (which is really
 * a slot) into 'l_name'. If successful also copy the real directory entry
 * into 'retdent'
 * Return 0 on success, -1 otherwise.
 */
__u8	 get_vfatname_block[MAX_CLUSTSIZE];
static int
get_vfatname(fsdata *mydata, int curclust, __u8 *cluster,
	     dir_entry *retdent, char *l_name)
{
	dir_entry *realdent;
	dir_slot  *slotptr = (dir_slot*) retdent;
	__u8	  *nextclust = cluster + mydata->clust_size * SECTOR_SIZE;
	__u8	   counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
	int idx = 0;

	while ((__u8*)slotptr < nextclust) {
		if (counter == 0) break;
		if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
			return -1;
		slotptr++;
		counter--;
	}

	if ((__u8*)slotptr >= nextclust) {
		dir_slot *slotptr2;

		slotptr--;
		curclust = get_fatent(mydata, curclust);
		if (curclust <= 0x0001 || curclust >= 0xfff0) {
			FAT_DPRINT("curclust: 0x%x\n", curclust);
			FAT_ERROR("Invalid FAT entry\n");
			return -1;
		}
		if (get_cluster(mydata, curclust, get_vfatname_block,
				mydata->clust_size * SECTOR_SIZE) != 0) {
			FAT_DPRINT("Error: reading directory block\n");
			return -1;
		}
		slotptr2 = (dir_slot*) get_vfatname_block;
		while (slotptr2->id > 0x01) {
			slotptr2++;
		}
		/* Save the real directory entry */
		realdent = (dir_entry*)slotptr2 + 1;
		while ((__u8*)slotptr2 >= get_vfatname_block) {
			slot2str(slotptr2, l_name, &idx);
			slotptr2--;
		}
	} else {
		/* Save the real directory entry */
		realdent = (dir_entry*)slotptr;
	}

	do {
		slotptr--;
		if (slot2str(slotptr, l_name, &idx)) break;
	} while (!(slotptr->id & LAST_LONG_ENTRY_MASK));

	l_name[idx] = '\0';
	if (*l_name == DELETED_FLAG) *l_name = '\0';
	else if (*l_name == aRING) *l_name = 'å';
	downcase(l_name);

	/* Return the real directory entry */
	memcpy(retdent, realdent, sizeof(dir_entry));

	return 0;
}


/* Calculate short name checksum */
static __u8
mkcksum(const char *str)
{
	int i;
	__u8 ret = 0;

	for (i = 0; i < 11; i++) {
		ret = (((ret&1)<<7)|((ret&0xfe)>>1)) + str[i];
	}

	return ret;
}
#endif


/*
 * Get the directory entry associated with 'filename' from the directory
 * starting at 'startsect'
 */
__u8 get_dentfromdir_block[MAX_CLUSTSIZE];
static dir_entry *get_dentfromdir (fsdata * mydata, int startsect,
				   char *filename, dir_entry * retdent,
				   int dols)
{
    __u16 prevcksum = 0xffff;
    __u32 curclust = START (retdent);
    int files = 0, dirs = 0;

    FAT_DPRINT ("get_dentfromdir: %s\n", filename);
    while (1) {
	dir_entry *dentptr;
	int i;

	if (get_cluster (mydata, curclust, get_dentfromdir_block,
		 mydata->clust_size * SECTOR_SIZE) != 0) {
	    FAT_DPRINT ("Error: reading directory block\n");
	    return NULL;
	}
	dentptr = (dir_entry *) get_dentfromdir_block;
	for (i = 0; i < DIRENTSPERCLUST; i++) {
	    char s_name[14], l_name[256];

	    l_name[0] = '\0';
	    if ((dentptr->attr & ATTR_VOLUME)) {
#ifdef CONFIG_SUPPORT_VFAT
		if ((dentptr->attr & ATTR_VFAT) &&
		    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
		    prevcksum = ((dir_slot *) dentptr)
			    ->alias_checksum;
		    get_vfatname (mydata, curclust, get_dentfromdir_block,
				  dentptr, l_name);
		    if (dols) {
			int isdir = (dentptr->attr & ATTR_DIR);
			char dirc;
			int doit = 0;

			if (isdir) {
			    dirs++;
			    dirc = '/';
			    doit = 1;
			} else {
			    dirc = ' ';
			    if (l_name[0] != 0) {
				files++;
				doit = 1;
			    }
			}
			if (doit) {
			    if (dirc == ' ') {
				printf (" %8ld   %s%c\n",
					(long) FAT2CPU32 (dentptr->size),
					l_name, dirc);
			    } else {
				printf ("            %s%c\n", l_name, dirc);
			    }
			}
			dentptr++;
			continue;
		    }
		    FAT_DPRINT ("vfatname: |%s|\n", l_name);
		} else
#endif
		{
		    /* Volume label or VFAT entry */
		    dentptr++;
		    continue;
		}
	    }
	    if (dentptr->name[0] == 0) {
		if (dols) {
		    printf ("\n%d file(s), %d dir(s)\n\n", files, dirs);
		}
		FAT_DPRINT ("Dentname == NULL - %d\n", i);
		return NULL;
	    }
#ifdef CONFIG_SUPPORT_VFAT
	    if (dols && mkcksum (dentptr->name) == prevcksum) {
		dentptr++;
		continue;
	    }
#endif
	    get_name (dentptr, s_name);
	    if (dols) {
		int isdir = (dentptr->attr & ATTR_DIR);
		char dirc;
		int doit = 0;

		if (isdir) {
		    dirs++;
		    dirc = '/';
		    doit = 1;
		} else {
		    dirc = ' ';
		    if (s_name[0] != 0) {
			files++;
			doit = 1;
		    }
		}
		if (doit) {
		    if (dirc == ' ') {
			printf (" %8ld   %s%c\n",
				(long) FAT2CPU32 (dentptr->size), s_name,
				dirc);
		    } else {
			printf ("            %s%c\n", s_name, dirc);
		    }
		}
		dentptr++;
		continue;
	    }
	    if (strcmp (filename, s_name) && strcmp (filename, l_name)) {
		FAT_DPRINT ("Mismatch: |%s|%s|\n", s_name, l_name);
		dentptr++;
		continue;
	    }
	    memcpy (retdent, dentptr, sizeof (dir_entry));

	    FAT_DPRINT ("DentName: %s", s_name);
	    FAT_DPRINT (", start: 0x%x", START (dentptr));
	    FAT_DPRINT (", size:  0x%x %s\n",
			FAT2CPU32 (dentptr->size),
			(dentptr->attr & ATTR_DIR) ? "(DIR)" : "");

	    return retdent;
	}
	curclust = get_fatent (mydata, curclust);
	if (curclust <= 0x0001 || curclust >= 0xfff0) {
	    FAT_DPRINT ("curclust: 0x%x\n", curclust);
	    FAT_ERROR ("Invalid FAT entry\n");
	    return NULL;
	}
    }

    return NULL;
}


/*
 * Read boot sector and volume info from a FAT filesystem
 */
static int
read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
{
	__u8 block[FS_BLOCK_SIZE];
	volume_info *vistart;

	if (disk_read(0, 1, block) < 0) {
		FAT_DPRINT("Error: reading block\n");
		return -1;
	}

	memcpy(bs, block, sizeof(boot_sector));
	bs->reserved	= FAT2CPU16(bs->reserved);
	bs->fat_length	= FAT2CPU16(bs->fat_length);
	bs->secs_track	= FAT2CPU16(bs->secs_track);
	bs->heads	= FAT2CPU16(bs->heads);
#if 0 /* UNUSED */
	bs->hidden	= FAT2CPU32(bs->hidden);
#endif
	bs->total_sect	= FAT2CPU32(bs->total_sect);

	/* FAT32 entries */
	if (bs->fat_length == 0) {
		/* Assume FAT32 */
		bs->fat32_length = FAT2CPU32(bs->fat32_length);
		bs->flags	 = FAT2CPU16(bs->flags);
		bs->root_cluster = FAT2CPU32(bs->root_cluster);
		bs->info_sector  = FAT2CPU16(bs->info_sector);
		bs->backup_boot  = FAT2CPU16(bs->backup_boot);
		vistart = (volume_info*) (block + sizeof(boot_sector));
		*fatsize = 32;
	} else {
		vistart = (volume_info*) &(bs->fat32_length);
		*fatsize = 0;
	}
	memcpy(volinfo, vistart, sizeof(volume_info));

	/* Terminate fs_type string. Writing past the end of vistart
	   is ok - it's just the buffer. */
	vistart->fs_type[8] = '\0';

	if (*fatsize == 32) {
		if (compare_sign(FAT32_SIGN, vistart->fs_type) == 0) {
			return 0;
		}
	} else {
		if (compare_sign(FAT12_SIGN, vistart->fs_type) == 0) {
			*fatsize = 12;
			return 0;
		}
		if (compare_sign(FAT16_SIGN, vistart->fs_type) == 0) {
			*fatsize = 16;
			return 0;
		}
	}

	FAT_DPRINT("Error: broken fs_type sign\n");
	return -1;
}


__u8 do_fat_read_block[MAX_CLUSTSIZE];  /* Block buffer */
static long
do_fat_read (const char *filename, void *buffer, unsigned long maxsize,
	     int dols)
{
    char fnamecopy[2048];
    boot_sector bs;
    volume_info volinfo;
    fsdata datablock;
    fsdata *mydata = &datablock;
    dir_entry *dentptr;
    __u16 prevcksum = 0xffff;
    char *subname = "";
    int rootdir_size, cursect;
    int idx, isdir = 0;
    int files = 0, dirs = 0;
    long ret = 0;
    int firsttime;

    if (read_bootsectandvi (&bs, &volinfo, &mydata->fatsize)) {
	FAT_DPRINT ("Error: reading boot sector\n");
	return -1;
    }
    if (mydata->fatsize == 32) {
	mydata->fatlength = bs.fat32_length;
    } else {
	mydata->fatlength = bs.fat_length;
    }
    mydata->fat_sect = bs.reserved;
    cursect = mydata->rootdir_sect
	    = mydata->fat_sect + mydata->fatlength * bs.fats;
    mydata->clust_size = bs.cluster_size;
    if (mydata->fatsize == 32) {
	rootdir_size = mydata->clust_size;
	mydata->data_begin = mydata->rootdir_sect   /* + rootdir_size */
		- (mydata->clust_size * 2);
    } else {
	rootdir_size = ((bs.dir_entries[1] * (int) 256 + bs.dir_entries[0])
			* sizeof (dir_entry)) / SECTOR_SIZE;
	mydata->data_begin = mydata->rootdir_sect + rootdir_size
		- (mydata->clust_size * 2);
    }
    mydata->fatbufnum = -1;

    FAT_DPRINT ("FAT%d, fatlength: %d\n", mydata->fatsize,
		mydata->fatlength);
    FAT_DPRINT ("Rootdir begins at sector: %d, offset: %x, size: %d\n"
		"Data begins at: %d\n",
		mydata->rootdir_sect, mydata->rootdir_sect * SECTOR_SIZE,
		rootdir_size, mydata->data_begin);
    FAT_DPRINT ("Cluster size: %d\n", mydata->clust_size);

    /* "cwd" is always the root... */
    while (ISDIRDELIM (*filename))
	filename++;
    /* Make a copy of the filename and convert it to lowercase */
    strcpy (fnamecopy, filename);
    downcase (fnamecopy);
    if (*fnamecopy == '\0') {
	if (!dols)
	    return -1;
	dols = LS_ROOT;
    } else if ((idx = dirdelim (fnamecopy)) >= 0) {
	isdir = 1;
	fnamecopy[idx] = '\0';
	subname = fnamecopy + idx + 1;
	/* Handle multiple delimiters */
	while (ISDIRDELIM (*subname))
	    subname++;
    } else if (dols) {
	isdir = 1;
    }

    while (1) {
	int i;

	if (disk_read (cursect, mydata->clust_size, do_fat_read_block) < 0) {
	    FAT_DPRINT ("Error: reading rootdir block\n");
	    return -1;
	}
	dentptr = (dir_entry *) do_fat_read_block;
	for (i = 0; i < DIRENTSPERBLOCK; i++) {
	    char s_name[14], l_name[256];

	    l_name[0] = '\0';
	    if ((dentptr->attr & ATTR_VOLUME)) {
#ifdef CONFIG_SUPPORT_VFAT
		if ((dentptr->attr & ATTR_VFAT) &&
		    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
		    prevcksum = ((dir_slot *) dentptr)->alias_checksum;
		    get_vfatname (mydata, 0, do_fat_read_block, dentptr, l_name);
		    if (dols == LS_ROOT) {
			int isdir = (dentptr->attr & ATTR_DIR);
			char dirc;
			int doit = 0;

			if (isdir) {
			    dirs++;
			    dirc = '/';
			    doit = 1;
			} else {
			    dirc = ' ';
			    if (l_name[0] != 0) {
				files++;
				doit = 1;
			    }
			}
			if (doit) {
			    if (dirc == ' ') {
				printf (" %8ld   %s%c\n",
					(long) FAT2CPU32 (dentptr->size),
					l_name, dirc);
			    } else {
				printf ("            %s%c\n", l_name, dirc);
			    }
			}
			dentptr++;
			continue;
		    }
		    FAT_DPRINT ("Rootvfatname: |%s|\n", l_name);
		} else
#endif
		{
		    /* Volume label or VFAT entry */
		    dentptr++;
		    continue;
		}
	    } else if (dentptr->name[0] == 0) {
		FAT_DPRINT ("RootDentname == NULL - %d\n", i);
		if (dols == LS_ROOT) {
		    printf ("\n%d file(s), %d dir(s)\n\n", files, dirs);
		    return 0;
		}
		return -1;
	    }
#ifdef CONFIG_SUPPORT_VFAT
	    else if (dols == LS_ROOT
		     && mkcksum (dentptr->name) == prevcksum) {
		dentptr++;
		continue;
	    }
#endif
	    get_name (dentptr, s_name);
	    if (dols == LS_ROOT) {
		int isdir = (dentptr->attr & ATTR_DIR);
		char dirc;
		int doit = 0;

		if (isdir) {
		    dirc = '/';
		    if (s_name[0] != 0) {
			dirs++;
			doit = 1;
		    }
		} else {
		    dirc = ' ';
		    if (s_name[0] != 0) {
			files++;
			doit = 1;
		    }
		}
		if (doit) {
		    if (dirc == ' ') {
			printf (" %8ld   %s%c\n",
				(long) FAT2CPU32 (dentptr->size), s_name,
				dirc);
		    } else {
			printf ("            %s%c\n", s_name, dirc);
		    }
		}
		dentptr++;
		continue;
	    }
	    if (strcmp (fnamecopy, s_name) && strcmp (fnamecopy, l_name)) {
		FAT_DPRINT ("RootMismatch: |%s|%s|\n", s_name, l_name);
		dentptr++;
		continue;
	    }
	    if (isdir && !(dentptr->attr & ATTR_DIR))
		return -1;

	    FAT_DPRINT ("RootName: %s", s_name);
	    FAT_DPRINT (", start: 0x%x", START (dentptr));
	    FAT_DPRINT (", size:  0x%x %s\n",
			FAT2CPU32 (dentptr->size), isdir ? "(DIR)" : "");

	    goto rootdir_done;  /* We got a match */
	}
	cursect++;
    }
  rootdir_done:

    firsttime = 1;
    while (isdir) {
	int startsect = mydata->data_begin
		+ START (dentptr) * mydata->clust_size;
	dir_entry dent;
	char *nextname = NULL;

	dent = *dentptr;
	dentptr = &dent;

	idx = dirdelim (subname);
	if (idx >= 0) {
	    subname[idx] = '\0';
	    nextname = subname + idx + 1;
	    /* Handle multiple delimiters */
	    while (ISDIRDELIM (*nextname))
		nextname++;
	    if (dols && *nextname == '\0')
		firsttime = 0;
	} else {
	    if (dols && firsttime) {
		firsttime = 0;
	    } else {
		isdir = 0;
	    }
	}

	if (get_dentfromdir (mydata, startsect, subname, dentptr,
			     isdir ? 0 : dols) == NULL) {
	    if (dols && !isdir)
		return 0;
	    return -1;
	}

	if (idx >= 0) {
	    if (!(dentptr->attr & ATTR_DIR))
		return -1;
	    subname = nextname;
	}
    }
    ret = get_contents (mydata, dentptr, buffer, maxsize);
    FAT_DPRINT ("Size: %d, got: %ld\n", FAT2CPU32 (dentptr->size), ret);

    return ret;
}


int
file_fat_detectfs(void)
{
	boot_sector	bs;
	volume_info	volinfo;
	int		fatsize;
	char	vol_label[12];

	if(cur_dev==NULL) {
		printf("No current device\n");
		return 1;
	}
#if (CONFIG_COMMANDS & CFG_CMD_IDE) || (CONFIG_COMMANDS & CFG_CMD_SCSI) || \
    (CONFIG_COMMANDS & CFG_CMD_USB) || (CONFIG_MMC)
	printf("Interface:  ");
	switch(cur_dev->if_type) {
		case IF_TYPE_IDE :	printf("IDE"); break;
		case IF_TYPE_SCSI :	printf("SCSI"); break;
		case IF_TYPE_ATAPI :	printf("ATAPI"); break;
		case IF_TYPE_USB :	printf("USB"); break;
		case IF_TYPE_DOC :	printf("DOC"); break;
		case IF_TYPE_MMC :	printf("MMC"); break;
		default :		printf("Unknown");
	}
	printf("\n  Device %d: ",cur_dev->dev);
	dev_print(cur_dev);
#endif
	if(read_bootsectandvi(&bs, &volinfo, &fatsize)) {
		printf("\nNo valid FAT fs found\n");
		return 1;
	}
	memcpy (vol_label, volinfo.volume_label, 11);
	vol_label[11] = '\0';
	volinfo.fs_type[5]='\0';
	printf("Partition %d: Filesystem: %s \"%s\"\n",cur_part,volinfo.fs_type,vol_label);
	return 0;
}


int
file_fat_ls(const char *dir)
{
	return do_fat_read(dir, NULL, 0, LS_YES);
}


long
file_fat_read(const char *filename, void *buffer, unsigned long maxsize)
{
	printf("reading %s\n",filename);
	return do_fat_read(filename, buffer, maxsize, LS_NO);
}

#endif /* #if (CONFIG_COMMANDS & CFG_CMD_FAT) */