StupidOS/tools/fat.c

227 lines
4.4 KiB
C
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#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdarg.h>
#include <libgen.h>
#include <errno.h>
typedef struct
{
uint8_t jmp[3];
uint8_t OEM[8];
uint16_t bytes_per_sector;
uint8_t sectors_per_cluster;
uint16_t reserved_sectors;
uint8_t number_of_FATs;
uint16_t root_entries;
uint16_t logical_sectors;
uint8_t media_descriptor;
uint16_t sectors_per_FAT;
uint16_t sectors_per_track;
uint16_t heads_per_cylinder;
uint32_t hidden_sectors;
uint32_t total_sectors;
/* EBPB */
uint8_t drive_number;
uint8_t flags;
uint8_t signature;
uint32_t serial;
uint8_t label[11];
uint8_t fs_type[8];
} __attribute__((packed)) BiosParamBlock;
typedef struct
{
uint8_t name[8];
uint8_t ext[3];
uint8_t attr;
uint16_t reserved0;
uint16_t creation_time;
uint16_t creation_date;
uint16_t access_date;
uint16_t reserved1;
uint16_t mod_time;
uint16_t mod_date;
uint16_t start;
uint32_t size;
} __attribute__((packed)) Entry;
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static const char *prg_name;
static int sector_size = 512;
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static void
fatal(const char *str, ...)
{
va_list ap;
fprintf(stderr, "%s: ", prg_name);
va_start(ap, str);
vfprintf(stderr, str, ap);
va_end(ap);
fprintf(stderr, "\n");
exit(EXIT_FAILURE);
}
static void
read_sector(uint8_t *dest, int sect, FILE *fp)
{
if (fseek(fp, sect*sector_size, SEEK_SET) != 0) goto fatal_sect;
if (fread(dest, 1, sector_size, fp) != sector_size) goto fatal_sect;
return;
fatal_sect:
fatal("Can't read sector %d", sect);
}
static void
dump_bpb(BiosParamBlock *bpb)
{
char label[12];
printf("Bytes per logical sector: %hd\n", bpb->bytes_per_sector);
sector_size = bpb->bytes_per_sector;
printf("Logical sectors per cluster: %d\n", bpb->sectors_per_cluster);
printf("Reserved logical sectors: %hd\n", bpb->reserved_sectors);
printf("Number of FATs: %d\n", bpb->number_of_FATs);
printf("Root directory entries: %hd\n", bpb->root_entries);
printf("Total logical sectors: %hd\n", bpb->logical_sectors);
printf("Logical sectors per FAT: %hd\n", bpb->sectors_per_FAT);
printf("Serial: %X\n", bpb->serial);
memset(label, 0, 12);
strncpy(label, bpb->label, 11);
printf("Label: '%s'\n", label);
printf("signature: %X\n", bpb->signature);
}
static void
dump_entry(Entry *entry)
{
char filename[9];
char ext[4];
int i;
if (entry->name[0] == 0x0) return;
memset(filename, 0, 9);
strncpy(filename, entry->name, 8);
memset(ext, 0, 4);
strncpy(ext, entry->ext, 3);
for (i = 7; i > 0; i--)
{
if (filename[i] == ' ')
{
filename[i] = '\0';
}
else
{
break;
}
}
printf("%s.%s\n", filename, ext);
}
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static void
dump(const char *img)
{
FILE *fp;
BiosParamBlock *bpb;
uint8_t buffer[512];
int root_start;
int root_size;
int i;
int j;
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fp = fopen(img, "rb");
if (fp == NULL) fatal("Can't open '%s': %s", img, strerror(errno));
read_sector(buffer, 0, fp);
if (buffer[511] != 0xAA || buffer[510] != 0x55)
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{
fatal("MBR not found");
}
bpb = (BiosParamBlock *)buffer;
dump_bpb(bpb);
root_start = bpb->sectors_per_FAT * bpb->number_of_FATs;
root_start += bpb->reserved_sectors;
root_size = bpb->root_entries / (sector_size >> 0x5);
for (i = 0; i < root_size; i++)
{
read_sector(buffer, root_start + i, fp);
for (j = 0; j < sector_size; j+=32)
{
dump_entry((Entry *)(buffer + j));
}
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}
fclose(fp);
exit(EXIT_SUCCESS);
}
static void
usage(int retcode)
{
if (retcode == EXIT_FAILURE)
{
fprintf(stderr, "Try '%s -h' form more information.\n", prg_name);
}
else
{
printf("Usage: %s [-hV] [-D IMG] [-b BIN]\n", prg_name);
printf("\t-h\tdisplay this help and exit\n");
printf("\t-V\toutput version information\n");
printf("\t-D IMG\tdump fs information from IMG\n");
printf("\nReport bugs to <%s>\n", MK_BUGREPORT);
}
exit(retcode);
}
static void
version(void)
{
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printf("%s commit %s\n", prg_name, MK_COMMIT);
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exit(EXIT_SUCCESS);
}
int
main(int argc, char **argv)
{
prg_name = argv[0];
while ((argc > 1) && (argv[1][0] == '-'))
{
switch (argv[1][1])
{
case 'h':
usage(EXIT_SUCCESS);
break;
case 'V':
version();
break;
case 'D':
argv++;
argc--;
if (argc <= 1) usage(EXIT_FAILURE);
dump(argv[1]);
break;
default:
usage(EXIT_FAILURE);
break;
}
argv++;
argc--;
}
return (EXIT_SUCCESS);
}