-
Notifications
You must be signed in to change notification settings - Fork 113
/
mkfs.fat.c
1690 lines (1450 loc) · 52.5 KB
/
mkfs.fat.c
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
/* mkfs.fat.c - utility to create FAT/MS-DOS filesystems
Copyright (C) 1991 Linus Torvalds <torvalds@klaava.helsinki.fi>
Copyright (C) 1992-1993 Remy Card <card@masi.ibp.fr>
Copyright (C) 1993-1994 David Hudson <dave@humbug.demon.co.uk>
Copyright (C) 1998 H. Peter Anvin <hpa@zytor.com>
Copyright (C) 1998-2005 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
Copyright (C) 2008-2014 Daniel Baumann <mail@daniel-baumann.ch>
Copyright (C) 2015-2016 Andreas Bombe <aeb@debian.org>
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 3 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, see <http://www.gnu.org/licenses/>.
The complete text of the GNU General Public License
can be found in /usr/share/common-licenses/GPL-3 file.
*/
/* Description: Utility to allow an MS-DOS filesystem to be created
under Linux. A lot of the basic structure of this program has been
borrowed from Remy Card's "mke2fs" code.
As far as possible the aim here is to make the "mkfs.fat" command
look almost identical to the other Linux filesystem make utilties,
eg bad blocks are still specified as blocks, not sectors, but when
it comes down to it, DOS is tied to the idea of a sector (512 bytes
as a rule), and not the block. For example the boot block does not
occupy a full cluster.
Fixes/additions May 1998 by Roman Hodek
<Roman.Hodek@informatik.uni-erlangen.de>:
- Atari format support
- New options -A, -S, -C
- Support for filesystems > 2GB
- FAT32 support */
/* Include the header files */
#include "version.h"
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
#include <ctype.h>
#include <stdint.h>
#include <getopt.h>
#include "endian_compat.h"
#include "msdos_fs.h"
#include "device_info.h"
/* Constant definitions */
#define TRUE 1 /* Boolean constants */
#define FALSE 0
#define TEST_BUFFER_BLOCKS 16
#define BLOCK_SIZE 1024
#define HARD_SECTOR_SIZE 512
#define SECTORS_PER_BLOCK ( BLOCK_SIZE / HARD_SECTOR_SIZE )
#define NO_NAME "NO NAME "
/* Macro definitions */
/* Report a failure message and return a failure error code */
#define die( str ) fatal_error( "%s: " str "\n" )
/* Mark a cluster in the FAT as bad */
#define mark_sector_bad( sector ) mark_FAT_sector( sector, FAT_BAD )
/* Compute ceil(a/b) */
static inline int cdiv(int a, int b)
{
return (a + b - 1) / b;
}
/* FAT values */
#define FAT_EOF (atari_format ? 0x0fffffff : 0x0ffffff8)
#define FAT_BAD 0x0ffffff7
#define MSDOS_EXT_SIGN 0x29 /* extended boot sector signature */
#define MSDOS_FAT12_SIGN "FAT12 " /* FAT12 filesystem signature */
#define MSDOS_FAT16_SIGN "FAT16 " /* FAT16 filesystem signature */
#define MSDOS_FAT32_SIGN "FAT32 " /* FAT32 filesystem signature */
#define BOOT_SIGN 0xAA55 /* Boot sector magic number */
#define MAX_CLUST_12 ((1 << 12) - 16)
#define MAX_CLUST_16 ((1 << 16) - 16)
#define MIN_CLUST_32 65529
/* M$ says the high 4 bits of a FAT32 FAT entry are reserved and don't belong
* to the cluster number. So the max. cluster# is based on 2^28 */
#define MAX_CLUST_32 ((1 << 28) - 16)
#define FAT12_THRESHOLD 4085
#define OLDGEMDOS_MAX_SECTORS 32765
#define GEMDOS_MAX_SECTORS 65531
#define GEMDOS_MAX_SECTOR_SIZE (16*1024)
#define BOOTCODE_SIZE 448
#define BOOTCODE_FAT32_SIZE 420
/* __attribute__ ((packed)) is used on all structures to make gcc ignore any
* alignments */
struct msdos_volume_info {
uint8_t drive_number; /* BIOS drive number */
uint8_t RESERVED; /* Unused */
uint8_t ext_boot_sign; /* 0x29 if fields below exist (DOS 3.3+) */
uint8_t volume_id[4]; /* Volume ID number */
uint8_t volume_label[11]; /* Volume label */
uint8_t fs_type[8]; /* Typically FAT12 or FAT16 */
} __attribute__ ((packed));
struct msdos_boot_sector {
uint8_t boot_jump[3]; /* Boot strap short or near jump */
uint8_t system_id[8]; /* Name - can be used to special case
partition manager volumes */
uint8_t sector_size[2]; /* bytes per logical sector */
uint8_t cluster_size; /* sectors/cluster */
uint16_t reserved; /* reserved sectors */
uint8_t fats; /* number of FATs */
uint8_t dir_entries[2]; /* root directory entries */
uint8_t sectors[2]; /* number of sectors */
uint8_t media; /* media code (unused) */
uint16_t fat_length; /* sectors/FAT */
uint16_t secs_track; /* sectors per track */
uint16_t heads; /* number of heads */
uint32_t hidden; /* hidden sectors (unused) */
uint32_t total_sect; /* number of sectors (if sectors == 0) */
union {
struct {
struct msdos_volume_info vi;
uint8_t boot_code[BOOTCODE_SIZE];
} __attribute__ ((packed)) _oldfat;
struct {
uint32_t fat32_length; /* sectors/FAT */
uint16_t flags; /* bit 8: fat mirroring, low 4: active fat */
uint8_t version[2]; /* major, minor filesystem version */
uint32_t root_cluster; /* first cluster in root directory */
uint16_t info_sector; /* filesystem info sector */
uint16_t backup_boot; /* backup boot sector */
uint16_t reserved2[6]; /* Unused */
struct msdos_volume_info vi;
uint8_t boot_code[BOOTCODE_FAT32_SIZE];
} __attribute__ ((packed)) _fat32;
} __attribute__ ((packed)) fstype;
uint16_t boot_sign;
} __attribute__ ((packed));
#define fat32 fstype._fat32
#define oldfat fstype._oldfat
struct fat32_fsinfo {
uint32_t reserved1; /* Nothing as far as I can tell */
uint32_t signature; /* 0x61417272L */
uint32_t free_clusters; /* Free cluster count. -1 if unknown */
uint32_t next_cluster; /* Most recently allocated cluster.
* Unused under Linux. */
uint32_t reserved2[4];
};
/* The "boot code" we put into the filesystem... it writes a message and
tells the user to try again */
unsigned char dummy_boot_jump[3] = { 0xeb, 0x3c, 0x90 };
unsigned char dummy_boot_jump_m68k[2] = { 0x60, 0x1c };
#define MSG_OFFSET_OFFSET 3
char dummy_boot_code[BOOTCODE_SIZE] = "\x0e" /* push cs */
"\x1f" /* pop ds */
"\xbe\x5b\x7c" /* mov si, offset message_txt */
/* write_msg: */
"\xac" /* lodsb */
"\x22\xc0" /* and al, al */
"\x74\x0b" /* jz key_press */
"\x56" /* push si */
"\xb4\x0e" /* mov ah, 0eh */
"\xbb\x07\x00" /* mov bx, 0007h */
"\xcd\x10" /* int 10h */
"\x5e" /* pop si */
"\xeb\xf0" /* jmp write_msg */
/* key_press: */
"\x32\xe4" /* xor ah, ah */
"\xcd\x16" /* int 16h */
"\xcd\x19" /* int 19h */
"\xeb\xfe" /* foo: jmp foo */
/* message_txt: */
"This is not a bootable disk. Please insert a bootable floppy and\r\n"
"press any key to try again ... \r\n";
#define MESSAGE_OFFSET 29 /* Offset of message in above code */
/* Global variables - the root of all evil :-) - see these and weep! */
static const char *program_name = "mkfs.fat"; /* Name of the program */
static char *device_name = NULL; /* Name of the device on which to create the filesystem */
static int atari_format = 0; /* Use Atari variation of MS-DOS FS format */
static int check = FALSE; /* Default to no readablity checking */
static int verbose = 0; /* Default to verbose mode off */
static long volume_id; /* Volume ID number */
static time_t create_time; /* Creation time */
static char volume_name[] = NO_NAME; /* Volume name */
static uint64_t blocks; /* Number of blocks in filesystem */
static int sector_size = 512; /* Size of a logical sector */
static int sector_size_set = 0; /* User selected sector size */
static int backup_boot = 0; /* Sector# of backup boot sector */
static int reserved_sectors = 0; /* Number of reserved sectors */
static int badblocks = 0; /* Number of bad blocks in the filesystem */
static int nr_fats = 2; /* Default number of FATs to produce */
static int size_fat = 0; /* Size in bits of FAT entries */
static int size_fat_by_user = 0; /* 1 if FAT size user selected */
static int dev = -1; /* FS block device file handle */
static int ignore_full_disk = 0; /* Ignore warning about 'full' disk devices */
static off_t currently_testing = 0; /* Block currently being tested (if autodetect bad blocks) */
static struct msdos_boot_sector bs; /* Boot sector data */
static int start_data_sector; /* Sector number for the start of the data area */
static int start_data_block; /* Block number for the start of the data area */
static unsigned char *fat; /* File allocation table */
static unsigned alloced_fat_length; /* # of FAT sectors we can keep in memory */
static unsigned fat_entries; /* total entries in FAT table (including reserved) */
static unsigned char *info_sector; /* FAT32 info sector */
static struct msdos_dir_entry *root_dir; /* Root directory */
static int size_root_dir; /* Size of the root directory in bytes */
static uint32_t num_sectors; /* Total number of sectors in device */
static int sectors_per_cluster = 0; /* Number of sectors per disk cluster */
static int root_dir_entries = 0; /* Number of root directory entries */
static char *blank_sector; /* Blank sector - all zeros */
static int hidden_sectors = 0; /* Number of hidden sectors */
static int hidden_sectors_by_user = 0; /* -h option invoked */
static int drive_number_option = 0; /* drive number */
static int drive_number_by_user = 0; /* drive number option invoked */
static int fat_media_byte = 0; /* media byte in header and starting FAT */
static int malloc_entire_fat = FALSE; /* Whether we should malloc() the entire FAT or not */
static int align_structures = TRUE; /* Whether to enforce alignment */
static int orphaned_sectors = 0; /* Sectors that exist in the last block of filesystem */
static int invariant = 0; /* Whether to set normally randomized or
current time based values to
constants */
/* Function prototype definitions */
static void fatal_error(const char *fmt_string) __attribute__ ((noreturn));
static void mark_FAT_cluster(int cluster, unsigned int value);
static void mark_FAT_sector(int sector, unsigned int value);
static long do_check(char *buffer, int try, off_t current_block);
static void alarm_intr(int alnum);
static void check_blocks(void);
static void get_list_blocks(char *filename);
static void check_mount(char *device_name);
static void establish_params(struct device_info *info);
static void setup_tables(void);
static void write_tables(void);
/* The function implementations */
/* Handle the reporting of fatal errors. Volatile to let gcc know that this doesn't return */
static void fatal_error(const char *fmt_string)
{
fprintf(stderr, fmt_string, program_name, device_name);
exit(1); /* The error exit code is 1! */
}
/* Mark the specified cluster as having a particular value */
static void mark_FAT_cluster(int cluster, unsigned int value)
{
if (cluster < 0 || cluster >= fat_entries)
die("Internal error: out of range cluster number in mark_FAT_cluster");
switch (size_fat) {
case 12:
value &= 0x0fff;
if (((cluster * 3) & 0x1) == 0) {
fat[3 * cluster / 2] = (unsigned char)(value & 0x00ff);
fat[(3 * cluster / 2) + 1] =
(unsigned char)((fat[(3 * cluster / 2) + 1] & 0x00f0)
| ((value & 0x0f00) >> 8));
} else {
fat[3 * cluster / 2] =
(unsigned char)((fat[3 * cluster / 2] & 0x000f) |
((value & 0x000f) << 4));
fat[(3 * cluster / 2) + 1] = (unsigned char)((value & 0x0ff0) >> 4);
}
break;
case 16:
value &= 0xffff;
fat[2 * cluster] = (unsigned char)(value & 0x00ff);
fat[(2 * cluster) + 1] = (unsigned char)(value >> 8);
break;
case 32:
value &= 0xfffffff;
fat[4 * cluster] = (unsigned char)(value & 0x000000ff);
fat[(4 * cluster) + 1] = (unsigned char)((value & 0x0000ff00) >> 8);
fat[(4 * cluster) + 2] = (unsigned char)((value & 0x00ff0000) >> 16);
fat[(4 * cluster) + 3] = (unsigned char)((value & 0xff000000) >> 24);
break;
default:
die("Bad FAT size (not 12, 16, or 32)");
}
}
/* Mark a specified sector as having a particular value in it's FAT entry */
static void mark_FAT_sector(int sector, unsigned int value)
{
int cluster = (sector - start_data_sector) / (int)(bs.cluster_size) /
(sector_size / HARD_SECTOR_SIZE) + 2;
if (sector < start_data_sector || sector >= num_sectors)
die("Internal error: out of range sector number in mark_FAT_sector");
mark_FAT_cluster(cluster, value);
}
/* Perform a test on a block. Return the number of blocks that could be read successfully */
static long do_check(char *buffer, int try, off_t current_block)
{
long got;
if (lseek(dev, current_block * BLOCK_SIZE, SEEK_SET) /* Seek to the correct location */
!=current_block * BLOCK_SIZE)
die("seek failed during testing for blocks");
got = read(dev, buffer, try * BLOCK_SIZE); /* Try reading! */
if (got < 0)
got = 0;
if (got & (BLOCK_SIZE - 1))
printf("Unexpected values in do_check: probably bugs\n");
got /= BLOCK_SIZE;
return got;
}
/* Alarm clock handler - display the status of the quest for bad blocks! Then retrigger the alarm for five senconds
later (so we can come here again) */
static void alarm_intr(int alnum)
{
(void)alnum;
if (currently_testing >= blocks)
return;
signal(SIGALRM, alarm_intr);
alarm(5);
if (!currently_testing)
return;
printf("%lld... ", (unsigned long long)currently_testing);
fflush(stdout);
}
static void check_blocks(void)
{
int try, got;
int i;
static char blkbuf[BLOCK_SIZE * TEST_BUFFER_BLOCKS];
if (verbose) {
printf("Searching for bad blocks ");
fflush(stdout);
}
currently_testing = 0;
if (verbose) {
signal(SIGALRM, alarm_intr);
alarm(5);
}
try = TEST_BUFFER_BLOCKS;
while (currently_testing < blocks) {
if (currently_testing + try > blocks)
try = blocks - currently_testing;
got = do_check(blkbuf, try, currently_testing);
currently_testing += got;
if (got == try) {
try = TEST_BUFFER_BLOCKS;
continue;
} else
try = 1;
if (currently_testing < start_data_block)
die("bad blocks before data-area: cannot make fs");
for (i = 0; i < SECTORS_PER_BLOCK; i++) /* Mark all of the sectors in the block as bad */
mark_sector_bad(currently_testing * SECTORS_PER_BLOCK + i);
badblocks++;
currently_testing++;
}
if (verbose)
printf("\n");
if (badblocks)
printf("%d bad block%s\n", badblocks, (badblocks > 1) ? "s" : "");
}
static void get_list_blocks(char *filename)
{
int i;
FILE *listfile;
long blockno;
char *line = NULL;
size_t linesize = 0;
int lineno = 0;
char *end, *check;
listfile = fopen(filename, "r");
if (listfile == (FILE *) NULL)
die("Can't open file of bad blocks");
while (1) {
lineno++;
ssize_t length = getline(&line, &linesize, listfile);
if (length < 0) {
if (errno == 0) /* end of file */
break;
perror("getline");
die("Error while reading bad blocks file");
}
errno = 0;
blockno = strtol(line, &end, 10);
if (errno) {
fprintf(stderr,
"While converting bad block number in line %d: %s\n",
lineno, strerror(errno));
die("Error in bad blocks file");
}
check = end;
while (*check) {
if (!isspace(*check)) {
fprintf(stderr,
"Badly formed number in bad blocks file line %d\n",
lineno);
die("Error in bad blocks file");
}
check++;
}
/* ignore empty or white space only lines */
if (end == line)
continue;
/* Mark all of the sectors in the block as bad */
for (i = 0; i < SECTORS_PER_BLOCK; i++) {
unsigned long sector = blockno * SECTORS_PER_BLOCK + i;
if (sector < start_data_sector) {
fprintf(stderr, "Block number %ld is before data area\n",
blockno);
die("Error in bad blocks file");
}
if (sector >= num_sectors) {
fprintf(stderr, "Block number %ld is behind end of filesystem\n",
blockno);
die("Error in bad blocks file");
}
mark_sector_bad(sector);
}
badblocks++;
}
fclose(listfile);
free(line);
if (badblocks)
printf("%d bad block%s\n", badblocks, (badblocks > 1) ? "s" : "");
}
/* Check to see if the specified device is currently mounted - abort if it is */
static void check_mount(char *device_name)
{
if (is_device_mounted(device_name))
die("%s contains a mounted filesystem.");
}
/* Establish the geometry and media parameters for the device */
static void establish_params(struct device_info *info)
{
unsigned int sec_per_track = 63;
unsigned int heads = 255;
unsigned int media = 0xf8;
unsigned int cluster_size = 4; /* starting point for FAT12 and FAT16 */
int def_root_dir_entries = 512;
if (info->size < 512 * 1024 * 1024) {
/*
* These values are more or less meaningless, but we can at least
* use less extreme values for smaller filesystems where the large
* dummy values signifying LBA only access are not needed.
*/
sec_per_track = 32;
heads = 64;
}
if (info->type != TYPE_FIXED) {
/* enter default parameters for floppy disks if the size matches */
switch (info->size / 1024) {
case 360:
sec_per_track = 9;
heads = 2;
media = 0xfd;
cluster_size = 2;
def_root_dir_entries = 112;
break;
case 720:
sec_per_track = 9;
heads = 2;
media = 0xf9;
cluster_size = 2;
def_root_dir_entries = 112;
break;
case 1200:
sec_per_track = 15;
heads = 2;
media = 0xf9;
cluster_size = (atari_format ? 2 : 1);
def_root_dir_entries = 224;
break;
case 1440:
sec_per_track = 18;
heads = 2;
media = 0xf0;
cluster_size = (atari_format ? 2 : 1);
def_root_dir_entries = 224;
break;
case 2880:
sec_per_track = 36;
heads = 2;
media = 0xf0;
cluster_size = 2;
def_root_dir_entries = 224;
break;
}
}
if (!size_fat && info->size >= 512 * 1024 * 1024) {
if (verbose)
printf("Auto-selecting FAT32 for large filesystem\n");
size_fat = 32;
}
if (size_fat == 32) {
/*
* For FAT32, try to do the same as M$'s format command
* (see http://www.win.tue.nl/~aeb/linux/fs/fat/fatgen103.pdf p. 20):
* fs size <= 260M: 0.5k clusters
* fs size <= 8G: 4k clusters
* fs size <= 16G: 8k clusters
* fs size <= 32G: 16k clusters
* fs size > 32G: 32k clusters
*
* This only works correctly for 512 byte sectors!
*/
uint32_t sz_mb = info->size / (1024 * 1024);
cluster_size =
sz_mb > 32 * 1024 ? 64 : sz_mb > 16 * 1024 ? 32 : sz_mb >
8 * 1024 ? 16 : sz_mb > 260 ? 8 : 1;
}
if (info->geom_heads > 0) {
heads = info->geom_heads;
sec_per_track = info->geom_sectors;
}
if (!hidden_sectors_by_user && info->geom_start >= 0)
hidden_sectors = htole32(info->geom_start);
if (!root_dir_entries)
root_dir_entries = def_root_dir_entries;
bs.secs_track = htole16(sec_per_track);
bs.heads = htole16(heads);
bs.media = media;
bs.cluster_size = cluster_size;
}
/*
* If alignment is enabled, round the first argument up to the second; the
* latter must be a power of two.
*/
static unsigned int align_object(unsigned int sectors, unsigned int clustsize)
{
if (align_structures)
return (sectors + clustsize - 1) & ~(clustsize - 1);
else
return sectors;
}
/* Create the filesystem data tables */
static void setup_tables(void)
{
unsigned cluster_count = 0, fat_length;
struct tm *ctime;
struct msdos_volume_info *vi =
(size_fat == 32 ? &bs.fat32.vi : &bs.oldfat.vi);
if (atari_format) {
/* On Atari, the first few bytes of the boot sector are assigned
* differently: The jump code is only 2 bytes (and m68k machine code
* :-), then 6 bytes filler (ignored), then 3 byte serial number. */
bs.boot_jump[2] = 'm';
memcpy((char *)bs.system_id, "kdosf", strlen("kdosf"));
} else
memcpy((char *)bs.system_id, "mkfs.fat", strlen("mkfs.fat"));
if (sectors_per_cluster)
bs.cluster_size = (char)sectors_per_cluster;
if (fat_media_byte)
bs.media = (char) fat_media_byte;
if (bs.media == 0xf8)
vi->drive_number=0x80;
else
vi->drive_number=0x00;
if (drive_number_by_user)
vi->drive_number= (char) drive_number_option;
if (size_fat == 32) {
/* Under FAT32, the root dir is in a cluster chain, and this is
* signalled by bs.dir_entries being 0. */
root_dir_entries = 0;
}
if (atari_format) {
bs.system_id[5] = (unsigned char)(volume_id & 0x000000ff);
bs.system_id[6] = (unsigned char)((volume_id & 0x0000ff00) >> 8);
bs.system_id[7] = (unsigned char)((volume_id & 0x00ff0000) >> 16);
} else {
vi->volume_id[0] = (unsigned char)(volume_id & 0x000000ff);
vi->volume_id[1] = (unsigned char)((volume_id & 0x0000ff00) >> 8);
vi->volume_id[2] = (unsigned char)((volume_id & 0x00ff0000) >> 16);
vi->volume_id[3] = (unsigned char)(volume_id >> 24);
}
if (!atari_format) {
memcpy(vi->volume_label, volume_name, 11);
memcpy(bs.boot_jump, dummy_boot_jump, 3);
/* Patch in the correct offset to the boot code */
bs.boot_jump[1] = ((size_fat == 32 ?
(char *)&bs.fat32.boot_code :
(char *)&bs.oldfat.boot_code) - (char *)&bs) - 2;
if (size_fat == 32) {
int offset = (char *)&bs.fat32.boot_code -
(char *)&bs + MESSAGE_OFFSET + 0x7c00;
if (dummy_boot_code[BOOTCODE_FAT32_SIZE - 1])
printf("Warning: message too long; truncated\n");
dummy_boot_code[BOOTCODE_FAT32_SIZE - 1] = 0;
memcpy(bs.fat32.boot_code, dummy_boot_code, BOOTCODE_FAT32_SIZE);
bs.fat32.boot_code[MSG_OFFSET_OFFSET] = offset & 0xff;
bs.fat32.boot_code[MSG_OFFSET_OFFSET + 1] = offset >> 8;
} else {
memcpy(bs.oldfat.boot_code, dummy_boot_code, BOOTCODE_SIZE);
}
bs.boot_sign = htole16(BOOT_SIGN);
} else {
memcpy(bs.boot_jump, dummy_boot_jump_m68k, 2);
}
if (verbose >= 2)
printf("Boot jump code is %02x %02x\n",
bs.boot_jump[0], bs.boot_jump[1]);
if (!reserved_sectors)
reserved_sectors = (size_fat == 32) ? 32 : 1;
else {
if (size_fat == 32 && reserved_sectors < 2)
die("On FAT32 at least 2 reserved sectors are needed.");
}
bs.reserved = htole16(reserved_sectors);
if (verbose >= 2)
printf("Using %d reserved sectors\n", reserved_sectors);
bs.fats = (char)nr_fats;
if (!atari_format || size_fat == 32)
bs.hidden = htole32(hidden_sectors);
else {
/* In Atari format, hidden is a 16 bit field */
uint16_t hidden = htole16(hidden_sectors);
if (hidden_sectors & ~0xffff)
die("#hidden doesn't fit in 16bit field of Atari format\n");
memcpy(&bs.hidden, &hidden, 2);
}
if ((long long)(blocks * BLOCK_SIZE / sector_size) + orphaned_sectors >
UINT32_MAX) {
printf("Warning: target too large, space at end will be left unused\n");
num_sectors = UINT32_MAX;
blocks = (uint64_t)UINT32_MAX * sector_size / BLOCK_SIZE;
} else {
num_sectors =
(long long)(blocks * BLOCK_SIZE / sector_size) + orphaned_sectors;
}
if (!atari_format) {
unsigned fatdata1216; /* Sectors for FATs + data area (FAT12/16) */
unsigned fatdata32; /* Sectors for FATs + data area (FAT32) */
unsigned fatlength12, fatlength16, fatlength32;
unsigned maxclust12, maxclust16, maxclust32;
unsigned clust12, clust16, clust32;
int maxclustsize;
unsigned root_dir_sectors = cdiv(root_dir_entries * 32, sector_size);
/*
* If the filesystem is 8192 sectors or less (4 MB with 512-byte
* sectors, i.e. floppy size), don't align the data structures.
*/
if (num_sectors <= 8192) {
if (align_structures && verbose >= 2)
printf("Disabling alignment due to tiny filesystem\n");
align_structures = FALSE;
}
if (sectors_per_cluster)
bs.cluster_size = maxclustsize = sectors_per_cluster;
else
/* An initial guess for bs.cluster_size should already be set */
maxclustsize = 128;
do {
fatdata32 = num_sectors
- align_object(reserved_sectors, bs.cluster_size);
fatdata1216 = fatdata32
- align_object(root_dir_sectors, bs.cluster_size);
if (verbose >= 2)
printf("Trying with %d sectors/cluster:\n", bs.cluster_size);
/* The factor 2 below avoids cut-off errors for nr_fats == 1.
* The "nr_fats*3" is for the reserved first two FAT entries */
clust12 = 2 * ((long long)fatdata1216 * sector_size + nr_fats * 3) /
(2 * (int)bs.cluster_size * sector_size + nr_fats * 3);
fatlength12 = cdiv(((clust12 + 2) * 3 + 1) >> 1, sector_size);
fatlength12 = align_object(fatlength12, bs.cluster_size);
/* Need to recalculate number of clusters, since the unused parts of the
* FATS and data area together could make up space for an additional,
* not really present cluster. */
clust12 = (fatdata1216 - nr_fats * fatlength12) / bs.cluster_size;
maxclust12 = (fatlength12 * 2 * sector_size) / 3;
if (maxclust12 > MAX_CLUST_12)
maxclust12 = MAX_CLUST_12;
if (verbose >= 2)
printf("FAT12: #clu=%u, fatlen=%u, maxclu=%u, limit=%u\n",
clust12, fatlength12, maxclust12, MAX_CLUST_12);
if (clust12 > maxclust12 - 2) {
clust12 = 0;
if (verbose >= 2)
printf("FAT12: too much clusters\n");
}
clust16 = ((long long)fatdata1216 * sector_size + nr_fats * 4) /
((int)bs.cluster_size * sector_size + nr_fats * 2);
fatlength16 = cdiv((clust16 + 2) * 2, sector_size);
fatlength16 = align_object(fatlength16, bs.cluster_size);
/* Need to recalculate number of clusters, since the unused parts of the
* FATS and data area together could make up space for an additional,
* not really present cluster. */
clust16 = (fatdata1216 - nr_fats * fatlength16) / bs.cluster_size;
maxclust16 = (fatlength16 * sector_size) / 2;
if (maxclust16 > MAX_CLUST_16)
maxclust16 = MAX_CLUST_16;
if (verbose >= 2)
printf("FAT16: #clu=%u, fatlen=%u, maxclu=%u, limit=%u\n",
clust16, fatlength16, maxclust16, MAX_CLUST_16);
if (clust16 > maxclust16 - 2) {
if (verbose >= 2)
printf("FAT16: too much clusters\n");
clust16 = 0;
}
/* The < 4078 avoids that the filesystem will be misdetected as having a
* 12 bit FAT. */
if (clust16 < FAT12_THRESHOLD
&& !(size_fat_by_user && size_fat == 16)) {
if (verbose >= 2)
printf(clust16 < FAT12_THRESHOLD ?
"FAT16: would be misdetected as FAT12\n" :
"FAT16: too much clusters\n");
clust16 = 0;
}
clust32 = ((long long)fatdata32 * sector_size + nr_fats * 8) /
((int)bs.cluster_size * sector_size + nr_fats * 4);
fatlength32 = cdiv((clust32 + 2) * 4, sector_size);
fatlength32 = align_object(fatlength32, bs.cluster_size);
/* Need to recalculate number of clusters, since the unused parts of the
* FATS and data area together could make up space for an additional,
* not really present cluster. */
clust32 = (fatdata32 - nr_fats * fatlength32) / bs.cluster_size;
maxclust32 = (fatlength32 * sector_size) / 4;
if (maxclust32 > MAX_CLUST_32)
maxclust32 = MAX_CLUST_32;
if (clust32 && clust32 < MIN_CLUST_32
&& !(size_fat_by_user && size_fat == 32)) {
clust32 = 0;
if (verbose >= 2)
printf("FAT32: not enough clusters (%d)\n", MIN_CLUST_32);
}
if (verbose >= 2)
printf("FAT32: #clu=%u, fatlen=%u, maxclu=%u, limit=%u\n",
clust32, fatlength32, maxclust32, MAX_CLUST_32);
if (clust32 > maxclust32) {
clust32 = 0;
if (verbose >= 2)
printf("FAT32: too much clusters\n");
}
if ((clust12 && (size_fat == 0 || size_fat == 12)) ||
(clust16 && (size_fat == 0 || size_fat == 16)) ||
(clust32 && size_fat == 32))
break;
bs.cluster_size <<= 1;
} while (bs.cluster_size && bs.cluster_size <= maxclustsize);
/* Use the optimal FAT size if not specified;
* FAT32 is (not yet) choosen automatically */
if (!size_fat) {
size_fat = (clust16 > clust12) ? 16 : 12;
if (verbose >= 2)
printf("Choosing %d bits for FAT\n", size_fat);
}
switch (size_fat) {
case 12:
cluster_count = clust12;
fat_length = fatlength12;
bs.fat_length = htole16(fatlength12);
memcpy(vi->fs_type, MSDOS_FAT12_SIGN, 8);
break;
case 16:
if (clust16 < FAT12_THRESHOLD) {
if (size_fat_by_user) {
fprintf(stderr, "WARNING: Not enough clusters for a "
"16 bit FAT! The filesystem will be\n"
"misinterpreted as having a 12 bit FAT without "
"mount option \"fat=16\".\n");
} else {
fprintf(stderr, "This filesystem has an unfortunate size. "
"A 12 bit FAT cannot provide\n"
"enough clusters, but a 16 bit FAT takes up a little "
"bit more space so that\n"
"the total number of clusters becomes less than the "
"threshold value for\n"
"distinction between 12 and 16 bit FATs.\n");
die("Make the filesystem a bit smaller manually.");
}
}
cluster_count = clust16;
fat_length = fatlength16;
bs.fat_length = htole16(fatlength16);
memcpy(vi->fs_type, MSDOS_FAT16_SIGN, 8);
break;
case 32:
if (clust32 < MIN_CLUST_32)
fprintf(stderr,
"WARNING: Not enough clusters for a 32 bit FAT!\n");
cluster_count = clust32;
fat_length = fatlength32;
bs.fat_length = htole16(0);
bs.fat32.fat32_length = htole32(fatlength32);
memcpy(vi->fs_type, MSDOS_FAT32_SIGN, 8);
root_dir_entries = 0;
break;
default:
die("FAT not 12, 16 or 32 bits");
}
/* Adjust the reserved number of sectors for alignment */
reserved_sectors = align_object(reserved_sectors, bs.cluster_size);
bs.reserved = htole16(reserved_sectors);
/* Adjust the number of root directory entries to help enforce alignment */
if (align_structures) {
root_dir_entries = align_object(root_dir_sectors, bs.cluster_size)
* (sector_size >> 5);
}
} else {
unsigned clusters, maxclust, fatdata;
/* GEMDOS always uses a 12 bit FAT on floppies, and always a 16 bit FAT on
* hard disks. So use 12 bit if the size of the filesystem suggests that
* this fs is for a floppy disk, if the user hasn't explicitly requested a
* size.
*/
if (!size_fat)
size_fat = (num_sectors == 1440 || num_sectors == 2400 ||
num_sectors == 2880 || num_sectors == 5760) ? 12 : 16;
if (verbose >= 2)
printf("Choosing %d bits for FAT\n", size_fat);
/* Atari format: cluster size should be 2, except explicitly requested by
* the user, since GEMDOS doesn't like other cluster sizes very much.
* Instead, tune the sector size for the FS to fit.
*/
bs.cluster_size = sectors_per_cluster ? sectors_per_cluster : 2;
if (!sector_size_set) {
while (num_sectors > GEMDOS_MAX_SECTORS) {
num_sectors >>= 1;
sector_size <<= 1;
}
}
if (verbose >= 2)
printf("Sector size must be %d to have less than %d log. sectors\n",
sector_size, GEMDOS_MAX_SECTORS);
/* Check if there are enough FAT indices for how much clusters we have */
do {
fatdata = num_sectors - cdiv(root_dir_entries * 32, sector_size) -
reserved_sectors;
/* The factor 2 below avoids cut-off errors for nr_fats == 1 and
* size_fat == 12
* The "2*nr_fats*size_fat/8" is for the reserved first two FAT entries
*/
clusters =
(2 *
((long long)fatdata * sector_size -
2 * nr_fats * size_fat / 8)) / (2 * ((int)bs.cluster_size *
sector_size +
nr_fats * size_fat / 8));
fat_length = cdiv((clusters + 2) * size_fat / 8, sector_size);
/* Need to recalculate number of clusters, since the unused parts of the
* FATS and data area together could make up space for an additional,
* not really present cluster. */
clusters = (fatdata - nr_fats * fat_length) / bs.cluster_size;
maxclust = (fat_length * sector_size * 8) / size_fat;
if (verbose >= 2)
printf("ss=%d: #clu=%d, fat_len=%d, maxclu=%d\n",
sector_size, clusters, fat_length, maxclust);
/* last 10 cluster numbers are special (except FAT32: 4 high bits rsvd);
* first two numbers are reserved */
if (maxclust <=
(size_fat == 32 ? MAX_CLUST_32 : (1 << size_fat) - 0x10)
&& clusters <= maxclust - 2)
break;
if (verbose >= 2)
printf(clusters > maxclust - 2 ?
"Too many clusters\n" : "FAT too big\n");
/* need to increment sector_size once more to */
if (sector_size_set)
die("With this sector size, the maximum number of FAT entries "
"would be exceeded.");
num_sectors >>= 1;
sector_size <<= 1;
} while (sector_size <= GEMDOS_MAX_SECTOR_SIZE);
if (sector_size > GEMDOS_MAX_SECTOR_SIZE)
die("Would need a sector size > 16k, which GEMDOS can't work with");
cluster_count = clusters;
if (size_fat != 32)
bs.fat_length = htole16(fat_length);
else {
bs.fat_length = 0;