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rockbox/firmware/fat.c

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First version git-svn-id: svn://svn.rockbox.org/rockbox/trunk@60 a1c6a512-1295-4272-9138-f99709370657
2002-03-28 15:09:10 +00:00
/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Linus Nielsen Feltzing
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <ctype.h>
#include <time.h>
#include <sys/timeb.h>
#include "fakestorage.h"
#include "fat.h"
#include "debug.h"
#define NUM_ROOT_DIR_ENTRIES 512
#define NUM_FATS 2
#define NUM_RESERVED_SECTORS 1
#define NUM_BLOCKS 10000
struct dsksz2secperclus
{
unsigned int disk_size;
unsigned int sec_per_cluster;
};
/*
** This is the table for FAT16 drives. NOTE that this table includes
** entries for disk sizes larger than 512 MB even though typically
** only the entries for disks < 512 MB in size are used.
** The way this table is accessed is to look for the first entry
** in the table for which the disk size is less than or equal
** to the DiskSize field in that table entry. For this table to
** work properly BPB_RsvdSecCnt must be 1, BPB_NumFATs
** must be 2, and BPB_RootEntCnt must be 512. Any of these values
** being different may require the first table entries DiskSize value
** to be changed otherwise the cluster count may be to low for FAT16.
*/
struct dsksz2secperclus dsk_table_fat16 [] =
{
{ 8400, 0}, /* disks up to 4.1 MB, the 0 value for SecPerClusVal
trips an error */
{ 32680, 2}, /* disks up to 16 MB, 1k cluster */
{ 262144, 4}, /* disks up to 128 MB, 2k cluster */
{ 524288, 8}, /* disks up to 256 MB, 4k cluster */
{ 1048576, 16}, /* disks up to 512 MB, 8k cluster */
/* The entries after this point are not used unless FAT16 is forced */
{ 2097152, 32}, /* disks up to 1 GB, 16k cluster */
{ 4194304, 64}, /* disks up to 2 GB, 32k cluster */
{ 0xFFFFFFFF, 0} /* any disk greater than 2GB,
0 value for SecPerClusVal trips an error */
};
int fat_num_rootdir_sectors(struct bpb *bpb);
int fat_first_sector_of_cluster(struct bpb *bpb, unsigned int cluster);
int fat_get_fatsize(struct bpb* bpb);
int fat_get_totsec(struct bpb* bpb);
int fat_get_rootdir_sector(struct bpb *bpb);
int fat_first_data_sector(struct bpb* bpb);
int fat_get_bpb(struct bpb *bpb);
int fat_bpb_is_sane(struct bpb *bpb);
int fat_create_fat(struct bpb* bpb);
int fat_dbg_read_block(char *name, unsigned char *buf);
int fat_flush_fat(struct bpb *bpb);
unsigned char *fat_cache_fat_sector(struct bpb *bpb, int secnum);
int fat_update_entry(struct bpb *bpb, int entry, unsigned int val);
unsigned int fat_getcurrdostime(unsigned short *dosdate,
unsigned short *dostime,
unsigned char *dostenth);
int fat_create_root_dir(struct bpb *bpb);
int fat_create_dos_name(unsigned char *name, unsigned char *newname);
int fat_create_file(struct bpb *bpb, unsigned int currdir, char *name);
unsigned char *fat_cache[256];
int fat_cache_dirty[256];
char current_directory[256] = "\\";
struct bpb *global_bpb;
struct disk_info di;
extern int yyparse(void);
void prompt(void)
{
printf("C:%s>", current_directory);
}
#ifdef TEST_FAT
int main(int argc, char *argv[])
{
struct bpb bpb;
memset(fat_cache, 0, sizeof(fat_cache));
memset(fat_cache_dirty, 0, sizeof(fat_cache_dirty));
disk_init(NUM_BLOCKS);
di.num_sectors = NUM_BLOCKS;
di.sec_per_track = 40;
di.num_heads = 250;
di.hidden_sectors = 0;
if(read_disk("diskdump.dmp") < 0)
{
printf("*** Warning! The disk is uninitialized\n");
}
else
{
fat_get_bpb(&bpb);
}
global_bpb = &bpb;
prompt();
yyparse();
dump_disk("diskdump.dmp");
return 0;
}
#endif
int fat_sec2cluster(struct bpb *bpb, unsigned int sec)
{
int first_sec = fat_first_data_sector(bpb);
if(sec < first_sec)
{
fprintf(stderr, "fat_sec2cluster() - Bad sector number (%d)\n", sec);
return -1;
}
return ((sec - first_sec) / bpb->bpb_secperclus) + 2;
}
int fat_last_cluster_in_chain(struct bpb *bpb, unsigned int cluster)
{
int iseof = 0;
switch(bpb->fat_type)
{
case FATTYPE_FAT12:
if(cluster >= 0x0ff8)
iseof = 1;
break;
case FATTYPE_FAT16:
if(cluster >= 0xfff8)
iseof = 1;
break;
case FATTYPE_FAT32:
if(cluster >= 0x0ffffff8)
iseof = 1;
break;
}
return iseof;
}
int fat_cluster2sec(struct bpb *bpb, unsigned int cluster)
{
int max_cluster = (fat_get_totsec(bpb) - fat_first_data_sector(bpb)) /
bpb->bpb_secperclus + 1;
if(cluster > max_cluster)
{
fprintf(stderr, "fat_cluster2sec() - Bad cluster number (%d)\n",
cluster);
return -1;
}
return fat_first_sector_of_cluster(bpb, cluster);
}
int fat_first_sector_of_cluster(struct bpb *bpb, unsigned int cluster)
{
return (cluster - 2) * bpb->bpb_secperclus + fat_first_data_sector(bpb);
}
int fat_num_rootdir_sectors(struct bpb *bpb)
{
return ((bpb->bpb_rootentcnt * 32) + (bpb->bpb_bytspersec - 1)) /
bpb->bpb_bytspersec;
}
int fat_get_fatsize(struct bpb* bpb)
{
if(bpb->bpb_fatsz16 != 0)
return bpb->bpb_fatsz16;
else
return bpb->bpb_fatsz32;
}
int fat_get_totsec(struct bpb* bpb)
{
if(bpb->bpb_totsec16 != 0)
return bpb->bpb_totsec16;
else
return bpb->bpb_totsec32;
}
int fat_get_rootdir_sector(struct bpb *bpb)
{
return bpb->bpb_rsvdseccnt + bpb->bpb_numfats * fat_get_fatsize(bpb);
}
int fat_first_data_sector(struct bpb* bpb)
{
int fatsz;
int rootdirsectors;
fatsz = fat_get_fatsize(bpb);
rootdirsectors = fat_num_rootdir_sectors(bpb);
return bpb->bpb_rsvdseccnt + bpb->bpb_numfats * fatsz + rootdirsectors;
}
int fat_format(struct disk_info *di, char *vol_name)
{
unsigned char buf[BLOCK_SIZE];
struct bpb bpb;
unsigned int root_dir_sectors;
unsigned int tmp1, tmp2;
int sec_per_clus = 0;
int fat_size;
int i = 0;
int err;
while(di->num_sectors > dsk_table_fat16[i].disk_size)
{
i++;
}
sec_per_clus = dsk_table_fat16[i].sec_per_cluster;
if(sec_per_clus == 0)
{
fprintf(stderr, "fat_format() - Bad disk size (%u)\n",
di->num_sectors);
return -1;
}
/* First calculate how many sectors we need for
the root directory */
root_dir_sectors = ((NUM_ROOT_DIR_ENTRIES * 32) +
(BLOCK_SIZE - 1)) / BLOCK_SIZE;
/* Now calculate the FAT size */
tmp1 = di->num_sectors - (NUM_RESERVED_SECTORS + root_dir_sectors);
tmp2 = (256 * sec_per_clus) + NUM_FATS;
fat_size = (tmp1 + (tmp2 - 1)) / tmp2;
/* Now create the BPB. We must be careful, so we really make
it little endian. */
memset(buf, 0xff, BLOCK_SIZE);
strncpy(&buf[BS_OEMNAME], "MSWIN4.1", 8);
buf[BPB_BYTSPERSEC] = BLOCK_SIZE & 0xff;
buf[BPB_BYTSPERSEC+1] = BLOCK_SIZE >> 8;
buf[BPB_SECPERCLUS] = sec_per_clus;
buf[BPB_RSVDSECCNT] = 1;
buf[BPB_RSVDSECCNT+1] = 0;
buf[BPB_NUMFATS] = 2;
buf[BPB_ROOTENTCNT] = NUM_ROOT_DIR_ENTRIES & 0xff;
buf[BPB_ROOTENTCNT+1] = NUM_ROOT_DIR_ENTRIES >> 8;
buf[BPB_TOTSEC16] = di->num_sectors & 0xff;
buf[BPB_TOTSEC16+1] = di->num_sectors >> 8;
buf[BPB_MEDIA] = 0xf0;
buf[BPB_FATSZ16] = fat_size & 0xff;
buf[BPB_FATSZ16+1] = fat_size >> 8;
buf[BPB_SECPERTRK] = di->sec_per_track & 0xff;
buf[BPB_SECPERTRK+1] = di->sec_per_track >> 8;
buf[BPB_NUMHEADS] = di->num_heads & 0xff;
buf[BPB_NUMHEADS+1] = di->num_heads >> 8;
buf[BPB_HIDDSEC] = di->hidden_sectors & 0xff;
buf[BPB_HIDDSEC+1] = (di->hidden_sectors >> 8) & 0xff;
buf[BPB_HIDDSEC+2] = (di->hidden_sectors >> 16) & 0xff;
buf[BPB_HIDDSEC+3] = (di->hidden_sectors >> 24) & 0xff;
buf[BPB_TOTSEC32] = 0;
buf[BPB_TOTSEC32+1] = 0;
buf[BPB_TOTSEC32+2] = 0;
buf[BPB_TOTSEC32+3] = 0;
buf[BS_DRVNUM] = 0;
buf[BS_RESERVED1] = 0;
buf[BS_BOOTSIG] = 0x29;
buf[BS_VOLID] = 0x78;
buf[BS_VOLID+1] = 0x56;
buf[BS_VOLID+2] = 0x34;
buf[BS_VOLID+3] = 0x12;
memset(&buf[BS_VOLLAB], ' ', 11);
strncpy(&buf[BS_VOLLAB], vol_name, MIN(11, strlen(vol_name));
strncpy(&buf[BS_FILSYSTYPE], "FAT16 ", 8);
/* The final signature */
buf[BPB_LAST_WORD] = 0x55;
buf[BPB_LAST_WORD+1] = 0xaa;
/* Now write the sector to disk */
err = write_block(buf, 0);
if(err < 0)
{
fprintf(stderr, "fat_format() - Couldn't write BSB (error code %i)\n",
err);
return -1;
}
if(fat_get_bpb(&bpb) < 0)
{
fprintf(stderr, "fat_format() - Couldn't read BPB\n");
return -1;
}
if(fat_create_fat(&bpb) < 0)
{
fprintf(stderr, "fat_format() - Couldn't create FAT\n");
return -1;
}
if(fat_create_root_dir(&bpb) < 0)
{
fprintf(stderr, "fat_format() - Couldn't write root dir sector\n");
return -1;
}
return 0;
}
int fat_get_bpb(struct bpb *bpb)
{
unsigned char buf[BLOCK_SIZE];
int err;
int fatsz;
int rootdirsectors;
int totsec;
int datasec;
int countofclusters;
/* Read the sector */
err = read_block(buf, 0);
if(err < 0)
{
fprintf(stderr, "fat_get_bpb() - Couldn't read BPB (error code %i)\n",
err);
return -1;
}
memset(bpb, 0, sizeof(struct bpb));
strncpy(bpb->bs_oemname, &buf[BS_OEMNAME], 8);
bpb->bs_oemname[8] = 0;
bpb->bpb_bytspersec = buf[BPB_BYTSPERSEC] | (buf[BPB_BYTSPERSEC+1] << 8);
bpb->bpb_secperclus = buf[BPB_SECPERCLUS];
bpb->bpb_rsvdseccnt = buf[BPB_RSVDSECCNT] | (buf[BPB_RSVDSECCNT+1] << 8);
bpb->bpb_numfats = buf[BPB_NUMFATS];
bpb->bpb_rootentcnt = buf[BPB_ROOTENTCNT] | (buf[BPB_ROOTENTCNT+1] << 8);
bpb->bpb_totsec16 = buf[BPB_TOTSEC16] | (buf[BPB_TOTSEC16+1] << 8);
bpb->bpb_media = buf[BPB_MEDIA];
bpb->bpb_fatsz16 = buf[BPB_FATSZ16] | (buf[BPB_FATSZ16+1] << 8);
bpb->bpb_secpertrk = buf[BPB_SECPERTRK] | (buf[BPB_SECPERTRK+1] << 8);
bpb->bpb_numheads = buf[BPB_NUMHEADS] | (buf[BPB_NUMHEADS+1] << 8);
bpb->bpb_hiddsec = buf[BPB_HIDDSEC] | (buf[BPB_HIDDSEC+1] << 8) |
(buf[BPB_HIDDSEC+2] << 16) | (buf[BPB_HIDDSEC+3] << 24);
bpb->bpb_totsec32 = buf[BPB_TOTSEC32] | (buf[BPB_TOTSEC32+1] << 8) |
(buf[BPB_TOTSEC32+2] << 16) | (buf[BPB_TOTSEC32+3] << 24);
bpb->bs_drvnum = buf[BS_DRVNUM];
bpb->bs_bootsig = buf[BS_BOOTSIG];
if(bpb->bs_bootsig == 0x29)
{
bpb->bs_volid = buf[BS_VOLID] | (buf[BS_VOLID+1] << 8) |
(buf[BS_VOLID+2] << 16) | (buf[BS_VOLID+3] << 24);
strncpy(bpb->bs_vollab, &buf[BS_VOLLAB], 11);
strncpy(bpb->bs_filsystype, &buf[BS_FILSYSTYPE], 8);
}
bpb->bpb_fatsz32 = (buf[BPB_FATSZ32] + (buf[BPB_FATSZ32+1] << 8)) |
(buf[BPB_FATSZ32+2] << 16) | (buf[BPB_FATSZ32+3] << 24);
bpb->last_word = buf[BPB_LAST_WORD] | (buf[BPB_LAST_WORD+1] << 8);
/* Determine FAT type */
fatsz = fat_get_fatsize(bpb);
if(bpb->bpb_totsec16 != 0)
totsec = bpb->bpb_totsec16;
else
totsec = bpb->bpb_totsec32;
rootdirsectors = fat_num_rootdir_sectors(bpb);
datasec = totsec - (bpb->bpb_rsvdseccnt + bpb->bpb_numfats * fatsz +
rootdirsectors);
countofclusters = datasec / bpb->bpb_secperclus;
if(countofclusters < 4085)
{
bpb->fat_type = FATTYPE_FAT12;
}
else
{
if(countofclusters < 65525)
{
bpb->fat_type = FATTYPE_FAT16;
}
else
{
bpb->fat_type = FATTYPE_FAT32;
}
}
if(fat_bpb_is_sane(bpb) < 0)
{
fprintf(stderr, "fat_get_bpb() - BPB is not sane\n");
return -1;
}
return 0;
}
int fat_bpb_is_sane(struct bpb *bpb)
{
if(bpb->fat_type == FATTYPE_FAT32)
{
fprintf(stderr, "fat_bpb_is_sane() - Error: FAT32 not supported\n");
return -1;
}
if(bpb->bpb_bytspersec != 512)
{
fprintf(stderr,
"fat_bpb_is_sane() - Warning: sector size is not 512 (%i)\n",
bpb->bpb_bytspersec);
}
if(bpb->bpb_secperclus * bpb->bpb_bytspersec > 32768)
{
fprintf(stderr,
"fat_bpb_is_sane() - Warning: cluster size is larger than 32K "
"(%i * %i = %i)\n",
bpb->bpb_bytspersec, bpb->bpb_secperclus,
bpb->bpb_bytspersec * bpb->bpb_secperclus);
}
if(bpb->bpb_rsvdseccnt != 1)
{
fprintf(stderr,
"fat_bpb_is_sane() - Warning: Reserved sectors is not 1 (%i)\n",
bpb->bpb_rsvdseccnt);
}
if(bpb->bpb_numfats != 2)
{
fprintf(stderr,
"fat_bpb_is_sane() - Warning: NumFATS is not 2 (%i)\n",
bpb->bpb_numfats);
}
if(bpb->bpb_rootentcnt != 512)
{
fprintf(stderr,
"fat_bpb_is_sane() - Warning: RootEntCnt is not 512 (%i)\n",
bpb->bpb_rootentcnt);
}
if(bpb->bpb_totsec16 < 200)
{
if(bpb->bpb_totsec16 == 0)
{
fprintf(stderr, "fat_bpb_is_sane() - Error: TotSec16 is 0\n");
return -1;
}
else
{
fprintf(stderr,
"fat_bpb_is_sane() - Warning: TotSec16 "
"is quite small (%i)\n",
bpb->bpb_totsec16);
}
}
if(bpb->bpb_media != 0xf0 && bpb->bpb_media < 0xf8)
{
fprintf(stderr,
"fat_bpb_is_sane() - Warning: Non-standard "
"media type (0x%02x)\n",
bpb->bpb_media);
}
if(bpb->last_word != 0xaa55)
{
fprintf(stderr, "fat_bpb_is_sane() - Error: Last word is not "
"0xaa55 (0x%04x)\n", bpb->last_word);
return -1;
}
return 0;
}
int fat_create_fat(struct bpb* bpb)
{
unsigned char *sec;
int i;
int secnum = 0;
int fatsz;
if(fat_bpb_is_sane(bpb) < 0)
{
fprintf(stderr, "fat_create_fat() - BPB is not sane\n");
return -1;
}
if(bpb->bpb_fatsz16 != 0)
fatsz = bpb->bpb_fatsz16;
else
fatsz = bpb->bpb_fatsz32;
sec = fat_cache_fat_sector(bpb, secnum);
if(!sec)
{
fprintf(stderr, "fat_create_fat() - Couldn't cache fat sector"
" (%d)\n", i);
return -1;
}
fat_cache_dirty[secnum] = 1;
/* First entry should have the media type in the
low byte and the rest of the bits set to 1.
The second should be the EOC mark. */
memset(sec, 0, BLOCK_SIZE);
sec[0] = bpb->bpb_media;
if(bpb->fat_type == FATTYPE_FAT12)
{
sec[1] = 0xff;
sec[2] = 0xff;
}
if(bpb->fat_type == FATTYPE_FAT16)
{
sec[0] = bpb->bpb_media;
sec[1] = 0xff;
sec[2] = 0xff;
sec[3] = 0xff;
}
secnum++;
for(i = 0; i < fatsz - 1;i++)
{
sec = fat_cache_fat_sector(bpb, secnum);
if(!sec)
{
fprintf(stderr, "fat_create_fat() - Couldn't cache fat sector"
" (%d)\n", i);
return -1;
}
fat_cache_dirty[secnum] = 1;
secnum++;
memset(sec, 0, BLOCK_SIZE);
}
if(fat_flush_fat(bpb) < 0)
{
fprintf(stderr, "fat_create_fat() - Couldn't flush fat\n");
return -1;
}
return 0;
}
int fat_dbg_read_block(char *name, unsigned char *buf)
{
FILE *f;
f = fopen(name, "rb");
if(f)
{
if(fread(buf, 1, 512, f) != 512)
{
fprintf(stderr, "Could not read file \"%s\"\n", name);
fclose(f);
return -1;
}
/* Now write the sector to disk */
write_block(buf, 0);
fclose(f);
}
else
{
fprintf(stderr, "Could not open file \"%s\"\n", name);
return -1;
}
return 0;
}
unsigned char *fat_cache_fat_sector(struct bpb *bpb, int secnum)
{
unsigned char *sec;
sec = fat_cache[secnum];
/* Load the sector if it is not cached */
if(!sec)
{
sec = malloc(bpb->bpb_bytspersec);
if(!sec)
{
fprintf(stderr, "fat_cache_fat_sector() - Out of memory\n");
return NULL;
}
if(read_block(sec, secnum + bpb->bpb_rsvdseccnt) < 0)
{
fprintf(stderr, "fat_cache_fat_sector() - Could"
" not read sector %d\n",
secnum);
free(sec);
return NULL;
}
fat_cache[secnum] = sec;
}
return sec;
}
int fat_update_entry(struct bpb *bpb, int entry, unsigned int val)
{
unsigned char *sec;
unsigned char *sec2;
int fatsz;
int fatoffset;
int thisfatsecnum;
int thisfatentoffset;
unsigned int tmp;
fatsz = fat_get_fatsize(bpb);
if(bpb->fat_type == FATTYPE_FAT12)
{
fatoffset = entry + (entry / 2);
}
else
{
if(bpb->fat_type == FATTYPE_FAT16)
fatoffset = entry * 2;
else
fatoffset = entry * 4;
}
thisfatsecnum = fatoffset / bpb->bpb_bytspersec;
thisfatentoffset = fatoffset % bpb->bpb_bytspersec;
sec = fat_cache_fat_sector(bpb, thisfatsecnum);
/* Load the sector if it is not cached */
if(!sec)
{
fprintf(stderr, "fat_update_entry() - Could not cache sector %d\n",
thisfatsecnum);
return -1;
}
fat_cache_dirty[thisfatsecnum] = 1;
switch(bpb->fat_type)
{
case FATTYPE_FAT12:
if(thisfatentoffset == bpb->bpb_bytspersec - 1)
{
/* This entry spans a sector boundary. Take care */
sec2 = fat_cache_fat_sector(bpb, thisfatsecnum + 1);
/* Load the sector if it is not cached */
if(!sec2)
{
fprintf(stderr, "fat_update_entry() - Could not "
"cache sector %d\n",
thisfatsecnum + 1);
return -1;
}
fat_cache_dirty[thisfatsecnum + 1] = 1;
}
else
{
if(entry & 1) /* Odd entry number? */
{
tmp = sec[thisfatentoffset] & 0xf0;
sec[thisfatentoffset] = tmp | (val & 0x0f);
sec[thisfatentoffset+1] = (val >> 4) & 0xff;
}
else
{
sec[thisfatentoffset] = val & 0xff;
tmp = sec[thisfatentoffset+1] & 0x0f;
sec[thisfatentoffset+1] = tmp | ((val >> 4) & 0xf0);
}
}
break;
case FATTYPE_FAT16:
*(unsigned short *)(&sec[thisfatentoffset]) = val;
break;
case FATTYPE_FAT32:
tmp = *(unsigned short *)(&sec[thisfatentoffset]) & 0xf000000;
val = tmp | (val & 0x0fffffff);
*(unsigned short *)(&sec[thisfatentoffset]) = val;
break;
}
return 0;
}
int fat_read_entry(struct bpb *bpb, int entry)
{
unsigned char *sec;
unsigned char *sec2;
int fatsz;
int fatoffset;
int thisfatsecnum;
int thisfatentoffset;
unsigned int val;
fatsz = fat_get_fatsize(bpb);
if(bpb->fat_type == FATTYPE_FAT12)
{
fatoffset = entry + (entry / 2);
}
else
{
if(bpb->fat_type == FATTYPE_FAT16)
fatoffset = entry * 2;
else
fatoffset = entry * 4;
}
thisfatsecnum = fatoffset / bpb->bpb_bytspersec;
thisfatentoffset = fatoffset % bpb->bpb_bytspersec;
sec = fat_cache_fat_sector(bpb, thisfatsecnum);
/* Load the sector if it is not cached */
if(!sec)
{
fprintf(stderr, "fat_update_entry() - Could not cache sector %d\n",
thisfatsecnum);
return -1;
}
switch(bpb->fat_type)
{
case FATTYPE_FAT12:
if(thisfatentoffset == bpb->bpb_bytspersec - 1)
{
/* This entry spans a sector boundary. Take care */
sec2 = fat_cache_fat_sector(bpb, thisfatsecnum + 1);
/* Load the sector if it is not cached */
if(!sec2)
{
fprintf(stderr, "fat_update_entry() - Could not "
"cache sector %d\n",
thisfatsecnum + 1);
return -1;
}
}
else
{
if(entry & 1) /* Odd entry number? */
{
val = (sec[thisfatentoffset] & 0x0f) |
(sec[thisfatentoffset+1] << 4);
}
else
{
val = (sec[thisfatentoffset] & 0xff) |
((sec[thisfatentoffset+1] & 0x0f) << 8);
}
}
break;
case FATTYPE_FAT16:
val = *(unsigned short *)(&sec[thisfatentoffset]);
break;
case FATTYPE_FAT32:
val = *(unsigned int *)(&sec[thisfatentoffset]);
break;
}
return val;
}
int fat_flush_fat(struct bpb *bpb)
{
int i;
int err;
unsigned char *sec;
int fatsz;
unsigned short d, t;
char m;
fatsz = fat_get_fatsize(bpb);
for(i = 0;i < 256;i++)
{
if(fat_cache[i] && fat_cache_dirty[i])
{
printf("Flushing FAT sector %d\n", i);
sec = fat_cache[i];
err = write_block(sec, i + bpb->bpb_rsvdseccnt);
if(err < 0)
{
fprintf(stderr, "fat_flush_fat() - Couldn't write"
" sector (%d)\n", i + bpb->bpb_rsvdseccnt);
return -1;
}
err = write_block(sec, i + bpb->bpb_rsvdseccnt + fatsz);
if(err < 0)
{
fprintf(stderr, "fat_flush_fat() - Couldn't write"
" sector (%d)\n", i + bpb->bpb_rsvdseccnt + fatsz);
return -1;
}
fat_cache_dirty[i] = 0;
}
}
fat_getcurrdostime(&d, &t, &m);
return 0;
}
unsigned int fat_getcurrdostime(unsigned short *dosdate,
unsigned short *dostime,
unsigned char *dostenth)
{
struct timeb tb;
struct tm *tm;
ftime(&tb);
tm = localtime(&tb.time);
*dosdate = ((tm->tm_year - 80) << 9) |
((tm->tm_mon + 1) << 5) |
(tm->tm_mday);
*dostime = (tm->tm_hour << 11) |
(tm->tm_min << 5) |
(tm->tm_sec >> 1);
*dostenth = (tm->tm_sec & 1) * 100 + tb.millitm / 10;
return 0;
}
int fat_create_root_dir(struct bpb *bpb)
{
unsigned char buf[BLOCK_SIZE];
int fatsz;
int sec;
int res;
int i;
unsigned short dosdate;
unsigned short dostime;
unsigned char dostenth;
int num_root_sectors;
fatsz = fat_get_fatsize(bpb);
sec = bpb->bpb_rsvdseccnt + bpb->bpb_numfats * fatsz;
memset(buf, 0, sizeof(buf));
strncpy(&buf[FATDIR_NAME], bpb->bs_vollab, 11);
buf[FATDIR_ATTR] = FAT_ATTR_VOLUME_ID;
buf[FATDIR_NTRES] = 0;
fat_getcurrdostime(&dosdate, &dostime, &dostenth);
buf[FATDIR_WRTDATE] = dosdate & 0xff;
buf[FATDIR_WRTDATE+1] = dosdate >> 8;
buf[FATDIR_WRTTIME] = dostime & 0xff;
buf[FATDIR_WRTTIME+1] = dostime >> 8;
printf("Writing rootdir to sector %d...\n", sec);
res = write_block(buf, sec);
if(res < 0)
{
fprintf(stderr, "fat_create_root_dir() - Couldn't write sector (%d)\n",
sec);
return -1;
}
printf("Clearing the rest of the root dir.\n");
sec++;
num_root_sectors = bpb->bpb_rootentcnt * 32 / bpb->bpb_bytspersec;
memset(buf, 0, BLOCK_SIZE);
for(i = 1;i < num_root_sectors;i++)
{
if(write_block(buf, sec++) < 0)
{
fprintf(stderr, "fat_create_root_dir() - "
" Couldn't write sector (%d)\n", sec);
return -1;
}
}
return 0;
}
int fat_get_next_cluster(struct bpb *bpb, unsigned int cluster)
{
int next_cluster = fat_read_entry(bpb, cluster);
if(fat_last_cluster_in_chain(bpb, next_cluster))
return 0;
else
return next_cluster;
}
int fat_add_dir_entry(struct bpb *bpb, unsigned int currdir,
struct fat_direntry *de)
{
unsigned char buf[BLOCK_SIZE];
unsigned char *eptr;
int i;
int err;
unsigned int sec;
unsigned int sec_cnt;
int need_to_update_last_empty_marker = 0;
int is_rootdir = (currdir == 0);
int done = 0;
unsigned char firstbyte;
if(is_rootdir)
{
sec = fat_get_rootdir_sector(bpb);
}
else
{
sec = fat_first_sector_of_cluster(bpb, currdir);
}
sec_cnt = 0;
while(!done)
{
/* The root dir has a fixed size */
if(is_rootdir)
{
if(sec_cnt >= bpb->bpb_rootentcnt * 32 / bpb->bpb_bytspersec)
{
/* We have reached the last sector of the root dir */
if(need_to_update_last_empty_marker)
{
/* Since the directory is full, there is no room for
a marker, so we just exit */
return 0;
}
else
{
fprintf(stderr, "fat_add_dir_entry() -"
" Root dir is full\n");
return -1;
}
}
}
else
{
if(sec_cnt >= bpb->bpb_secperclus)
{
/* We have reached the end of this cluster */
printf("Moving to the next cluster...");
currdir = fat_get_next_cluster(bpb, currdir);
printf("new cluster is %d\n", currdir);
if(!currdir)
{
/* This was the last in the chain,
we have to allocate a new cluster */
/* TODO */
}
}
}
printf("Reading sector %d...\n", sec);
/* Read the next sector in the current dir */
err = read_block(buf, sec);
if(err < 0)
{
fprintf(stderr, "fat_add_dir_entry() - Couldn't read dir sector"
" (error code %i)\n", err);
return -1;
}
if(need_to_update_last_empty_marker)
{
/* All we need to do is to set the first entry to 0 */
printf("Clearing the first entry in sector %d\n", sec);
buf[0] = 0;
done = 1;
}
else
{
/* Look for a free slot */
for(i = 0;i < BLOCK_SIZE;i+=32)
{
firstbyte = buf[i];
if(firstbyte == 0xe5 || firstbyte == 0)
{
printf("Found free slot at entry %d in sector %d\n",
i/32, sec);
eptr = &buf[i];
memset(eptr, 0, 32);
strncpy(&eptr[FATDIR_NAME], de->name, 11);
eptr[FATDIR_ATTR] = de->attr;
eptr[FATDIR_NTRES] = 0;
eptr[FATDIR_CRTTIMETENTH] = de->crttimetenth;
eptr[FATDIR_CRTDATE] = de->crtdate & 0xff;
eptr[FATDIR_CRTDATE+1] = de->crtdate >> 8;
eptr[FATDIR_CRTTIME] = de->crttime & 0xff;
eptr[FATDIR_CRTTIME+1] = de->crttime >> 8;
eptr[FATDIR_WRTDATE] = de->wrtdate & 0xff;
eptr[FATDIR_WRTDATE+1] = de->wrtdate >> 8;
eptr[FATDIR_WRTTIME] = de->wrttime & 0xff;
eptr[FATDIR_WRTTIME+1] = de->wrttime >> 8;
eptr[FATDIR_FILESIZE] = de->filesize & 0xff;
eptr[FATDIR_FILESIZE+1] = (de->filesize >> 8) & 0xff;
eptr[FATDIR_FILESIZE+2] = (de->filesize >> 16) & 0xff;
eptr[FATDIR_FILESIZE+3] = (de->filesize >> 24) & 0xff;
/* Advance the last_empty_entry marker */
if(firstbyte == 0)
{
i += 32;
if(i < BLOCK_SIZE)
{
buf[i] = 0;
/* We are done */
done = 1;
}
else
{
/* We must fill in the first entry
in the next sector */
need_to_update_last_empty_marker = 1;
}
}
err = write_block(buf, sec);
if(err < 0)
{
fprintf(stderr, "fat_add_dir_entry() - "
" Couldn't write dir"
" sector (error code %i)\n", err);
return -1;
}
break;
}
}
}
sec++;
sec_cnt++;
}
return 0;
}
unsigned char fat_char2dos(unsigned char c)
{
switch(c)
{
case 0xe5: /* Special kanji character */
c = 0x05;
break;
case 0x22:
case 0x2a:
case 0x2b:
case 0x2c:
case 0x2e:
case 0x3a:
case 0x3b:
case 0x3c:
case 0x3d:
case 0x3e:
case 0x3f:
case 0x5b:
case 0x5c:
case 0x5d:
case 0x7c:
/* Illegal name */
c = 0;
break;
default:
if(c < 0x20)
{
/* Illegal name */
c = 0;
}
break;
}
return c;
}
int fat_create_dos_name(unsigned char *name, unsigned char *newname)
{
unsigned char n[12];
unsigned char c;
int i;
char *ext;
if(strlen(name) > 12)
{
return -1;
}
strcpy(n, name);
ext = strchr(n, '.');
if(ext)
{
*ext++ = 0;
}
/* The file name is either empty, or there was only an extension.
In either case it is illegal. */
if(n[0] == 0)
{
return -1;
}
/* Name part */
for(i = 0;n[i] && (i < 8);i++)
{
c = fat_char2dos(n[i]);
if(c)
{
newname[i] = toupper(c);
}
}
while(i < 8)
{
newname[i++] = ' ';
}
/* Extension part */
for(i = 0;ext && ext[i] && (i < 3);i++)
{
c = fat_char2dos(ext[i]);
if(c)
{
newname[8+i] = toupper(c);
}
}
while(i < 3)
{
newname[8+i++] = ' ';
}
return 0;
}
int fat_create_dir(struct bpb *bpb, unsigned int currdir, char *name)
{
struct fat_direntry de;
int err;
printf("fat_create_file()\n");
memset(&de, 0, sizeof(struct fat_direntry));
if(fat_create_dos_name(name, de.name) < 0)
{
fprintf(stderr, "fat_create_file() - Illegal file name (%s)\n", name);
return -1;
}
fat_getcurrdostime(&de.crtdate, &de.crttime, &de.crttimetenth);
de.wrtdate = de.crtdate;
de.wrttime = de.crttime;
de.filesize = 0;
de.attr = FAT_ATTR_DIRECTORY;
err = fat_add_dir_entry(bpb, currdir, &de);
return 0;
}
int fat_create_file(struct bpb *bpb, unsigned int currdir, char *name)
{
struct fat_direntry de;
int err;
printf("fat_create_file()\n");
memset(&de, 0, sizeof(struct fat_direntry));
if(fat_create_dos_name(name, de.name) < 0)
{
fprintf(stderr, "fat_create_file() - Illegal file name (%s)\n", name);
return -1;
}
fat_getcurrdostime(&de.crtdate, &de.crttime, &de.crttimetenth);
de.wrtdate = de.crtdate;
de.wrttime = de.crttime;
de.filesize = 0;
err = fat_add_dir_entry(bpb, currdir, &de);
return err;
}
void fat_fill_direntry(struct fat_direntry *de, char *buf)
{
memset(de, 0, sizeof(struct fat_direntry));
strncpy(de->name, &buf[FATDIR_NAME], 11);
de->attr = buf[FATDIR_ATTR];
de->crttimetenth = buf[FATDIR_CRTTIMETENTH];
de->crtdate = buf[FATDIR_CRTDATE] | (buf[FATDIR_CRTDATE+1] << 8);
de->crttime = buf[FATDIR_CRTTIME] | (buf[FATDIR_CRTTIME+1] << 8);
de->wrtdate = buf[FATDIR_WRTDATE] | (buf[FATDIR_WRTDATE+1] << 8);
de->wrttime = buf[FATDIR_WRTTIME] | (buf[FATDIR_WRTTIME+1] << 8);
de->filesize = buf[FATDIR_FILESIZE] |
(buf[FATDIR_FILESIZE+1] << 8) |
(buf[FATDIR_FILESIZE+2] << 16) |
(buf[FATDIR_FILESIZE+3] << 24);
}
int fat_opendir(struct bpb *bpb, struct fat_dirent *ent, unsigned int currdir)
{
int is_rootdir = (currdir == 0);
unsigned int sec;
int err;
if(is_rootdir)
{
sec = fat_get_rootdir_sector(bpb);
}
else
{
sec = fat_first_sector_of_cluster(bpb, currdir);
}
/* Read the first sector in the current dir */
err = read_block(ent->cached_buf, sec);
if(err < 0)
{
fprintf(stderr, "fat_getfirst() - Couldn't read dir sector"
" (error code %i)\n", err);
return -1;
}
ent->entry = 0;
ent->cached_sec = sec;
ent->num_sec = 0;
return 0;
}
int fat_getnext(struct bpb *bpb, struct fat_dirent *ent,
struct fat_direntry *entry)
{
int done = 0;
int i;
int err;
unsigned char firstbyte;
while(!done)
{
/* Look for a free slot */
for(i = ent->entry;i < BLOCK_SIZE/32;i++)
{
firstbyte = ent->cached_buf[i*32];
if(firstbyte == 0xe5)
{
continue;
}
if(firstbyte == 0)
{
return -1;
}
fat_fill_direntry(entry, &ent->cached_buf[i*32]);
done = 1;
break;
}
/* Next sector? */
if(i >= BLOCK_SIZE/32)
{
ent->num_sec++;
ent->cached_sec++;
/* Do we need to advance one cluster? */
if(ent->num_sec >= bpb->bpb_secperclus)
{
ent->num_sec = 0;
ent->cached_sec = fat_get_next_cluster(
bpb, fat_sec2cluster(bpb, ent->cached_sec));
if(!ent->cached_sec)
{
printf("End of cluster chain.\n");
return -1;
}
}
/* Read the next sector */
err = read_block(ent->cached_buf, ent->cached_sec);
if(err < 0)
{
fprintf(stderr, "fat_getnext() - Couldn't read dir sector"
" (error code %i)\n", err);
return -1;
}
i = 0;
}
else
{
i++;
}
ent->entry = i;
}
return 0;
}
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