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/*
* This file is part of the Advance project.
*
* Copyright (C) 2004 Andrea Mazzoleni
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "portable.h"
#include "part.h"
#include "fat.h"
#include "error.h"
static void part_entry_set(struct partition_entry* entry, unsigned offset, unsigned size, const struct disk_geometry* geometry)
{
unsigned h, s, c;
unsigned start, end;
le_uint32_write(entry->start, offset);
le_uint32_write(entry->size, size);
start = offset;
end = offset + size - 1;
s = (start % geometry->sectors) + 1;
start /= geometry->sectors;
h = start % geometry->heads;
start /= geometry->heads;
c = start;
entry->start_head = h;
entry->start_seccyl[0] = (s & 0x3F) | ((c >> 2) & 0xc0);
entry->start_seccyl[1] = c & 0xFF;
s = (end % geometry->sectors) + 1;
end /= geometry->sectors;
h = end % geometry->heads;
end /= geometry->heads;
c = end;
entry->end_head = h;
entry->end_seccyl[0] = (s & 0x3F) | ((c >> 2) & 0xc0);
entry->end_seccyl[1] = c & 0xFF;
}
/**
* Create a partition table filled with a bootable FAT partition.
* \param entry Partition entry to use. From 0 to 3.
* The boot code is not modified.
*/
void part_setup(unsigned char* mbr, unsigned entry, unsigned fat_bit, unsigned fat_begin, unsigned fat_size, const struct disk_geometry* geometry)
{
struct partition_table* part = (struct partition_table*)mbr;
/* clear the table */
memset(part->entries, 0, sizeof(part->entries));
part->entries[entry].status = 0x80;
if (fat_bit == 12)
part->entries[entry].type = 1; /* FAT 12 */
else if (fat_bit == 16)
part->entries[entry].type = 6; /* FAT 16 (>32M) */
else if (fat_bit == 32)
part->entries[entry].type = 0xb; /* W95 FAT 32 */
else
part->entries[entry].type = 0;
assert(fat_begin + fat_size <= geometry->size);
part_entry_set(&part->entries[entry], fat_begin, fat_size, geometry);
part->id[0] = 0x55;
part->id[1] = 0xAA;
}
/**
* Change the specified MBR sector to be a FAT boot sector.
* \param mbr MBR to change.
* \param boot FAT boot sector to imitate.
* \param bit FAT bit (12, 16 or 32).
* \param pos Position of the FAT boot sector on the disk (in number of sectors).
*/
int part_fat_setup(unsigned char* mbr, const unsigned char* boot, unsigned bit, unsigned pos)
{
struct fat_boot_sector* fat;
unsigned size_in_sector;
unsigned code_start;
if ((mbr[0] != 0xEB || mbr[2] != 0x90) && (mbr[0] != 0xE9)) {
error_set("Invalid jump signature in the mbr sector.");
return -1;
}
if (mbr[510] != 0x55 || mbr[511] != 0xAA) {
error_set("Invalid end AA55 signature in the mbr sector.");
return -1;
}
if (mbr[0] == 0xEB) {
code_start = mbr[1] + 2;
} else {
error_set("Unsupported jump in the mbr sector.");
return -1;
}
if (bit == 32 && code_start < 0x5A) {
error_set("Invalid code start %X in the mbr sector (for fat32 it must be at least 5A).", code_start);
return -1;
}
if (code_start < 0x3E) {
error_set("Invalid code start %X in the mbr sector (it must be at least 3E).", code_start);
return -1;
}
/* copy the FAT boot sector info */
if (bit == 32)
memcpy(mbr + 3, boot + 3, 0x5A - 3);
else
memcpy(mbr + 3, boot + 3, 0x3E - 3);
fat = (struct fat_boot_sector*)mbr;
/* increment the number of reserved sector */
le_uint16_write(&fat->BPB_RsvdSecCnt, le_uint16_read(&fat->BPB_RsvdSecCnt) + pos);
/* set the number of hidden sector */
if (le_uint32_read(&fat->BPB_HiddSec) != pos) {
error_set("Invalid number of hidden sector in the fat boot sector, it must be %d.", pos);
return -1;
}
le_uint32_write(&fat->BPB_HiddSec, 0);
/* increment the number of total sectors */
if (le_uint32_read(fat->BPB_TotSec32) != 0)
size_in_sector = le_uint32_read(fat->BPB_TotSec32);
else
size_in_sector = le_uint16_read(fat->BPB_TotSec16);
size_in_sector += pos;
if (bit == 32 || size_in_sector >= 0x10000) {
le_uint16_write(fat->BPB_TotSec16, 0);
le_uint32_write(fat->BPB_TotSec32, size_in_sector);
} else {
le_uint16_write(fat->BPB_TotSec16, size_in_sector);
le_uint32_write(fat->BPB_TotSec32, 0);
}
/* increment other fat32 pointers */
if (bit == 32) {
le_uint16_write(fat->bit.fat32.BPB_FSInfo, le_uint16_read(fat->bit.fat32.BPB_FSInfo) + pos);
/* no backup */
le_uint16_write(fat->bit.fat32.BPB_BkBootSec, 0);
}
return 0;
}
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