fs_part.c

pocket pc hx4700 bootloader

/* part of Embedded OS Loader source code
 *
 *   Copyright 2005 Vivien Chappelier <[e-mail]>
 *   Copyright 2006-2007 Pawel Kolodziejski - adopted to linux native bootloader
 *
 * This software is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This software 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
 * Library General Public License for more details.
 *
 */

#include "types.h"
#include "fs_types.h"

static void chs_decode(chs_t *chs, unsigned char *addr) {
	chs->h = addr[0];
	chs->s = addr[1] & 0x3f;
	chs->c = ((addr[1] & 0xc0) << 2) | addr[2];
}

static void read_pentry(unsigned char *buffer, pentry_t *pentry) {
	pentry->boot = buffer[0];
	chs_decode(&pentry->begin, &buffer[1]);
	pentry->type = buffer[4];
	chs_decode(&pentry->end, &buffer[5]);
	pentry->sector_start   = buffer[ 8];
	pentry->sector_start  |= buffer[ 9] <<  8;
	pentry->sector_start  |= buffer[10] << 16;
	pentry->sector_start  |= buffer[11] << 24;
	pentry->sector_length  = buffer[12];
	pentry->sector_length |= buffer[13] <<  8;
	pentry->sector_length |= buffer[14] << 16;
	pentry->sector_length |= buffer[15] << 24;
}

static int read_ptable(unsigned char bootsector[], pentry_t *parent, pentry_t *ptable) {
	/* check for the signature at offset 510 */
	if (bootsector[510] != 0x55 || bootsector[511] != 0xaa) {
		return 0;
	}

	/* partition descriptors are at offset 446, 462, 478 and 494 */
	if (!parent) {
		/* MBR */
		read_pentry(&bootsector[446], &ptable[0]);
		read_pentry(&bootsector[462], &ptable[1]);
		read_pentry(&bootsector[478], &ptable[2]);
		read_pentry(&bootsector[494], &ptable[3]);
		return 4;
	} else {
		/* EMBR */
		read_pentry(&bootsector[446], &ptable[0]);
		read_pentry(&bootsector[462], &ptable[1]);
		ptable[0].sector_start += parent->sector_start;
		ptable[1].sector_start += parent->sector_start;
		return 2;
	}
}

grub_file_t grub_file_open(grub_disk_t disk, const char *file_name);
grub_ssize_t grub_file_read(grub_file_t file, char *buf, grub_size_t len);
grub_off_t grub_file_seek(grub_file_t file, grub_off_t offset);
void grub_file_close(grub_file_t file);

int sd_read_sector(char *buffer, unsigned long sector);
int cf_read_sector(char *buffer, unsigned long sector);

int read_file(char *filename, char *buffer, int fs_type, int card_type, int nb_sectors) {
	int i;
	int found = 0;
	struct grub_disk disk;
	grub_file_t file = 0;
	grub_err_t status = GRUB_ERR_NONE;

	memset(&disk, 0, sizeof(disk));
	disk.pcount = 0;
	disk.card_type = card_type;
	disk.fs_type = fs_type;

	if (card_type == 0)
		disk.read = sd_read_sector;
	else if (card_type == 1)
		disk.read = cf_read_sector;
	else {
		return 0;
	}

	memset((char *)0xA3100300, 0, 32);
	memset((char *)0xA3100400, 0, 64000);

	disk.read(buffer, 0);
	disk.pcount += read_ptable(buffer, NULL, disk.ptable);

	disk.cur_ptable = -1;

	for (i = 0; i < disk.pcount; i++) {
		switch (disk.ptable[i].type) {
		case 0x00: /* empty */
			break;
		case 0x01: /* FAT12 */
                        if (fs_type == 1) {
				found = 1;
				disk.cur_ptable = i;
			}
			break;
		case 0x05: /* extended */
			/* read the first sector of the extended partition */
			if (disk.pcount <= 16) {
				disk.read((char *)buffer, disk.ptable[i].sector_start * 512);
				disk.pcount += read_ptable(buffer, &disk.ptable[i], &disk.ptable[disk.pcount]);
			} else {
				//printf("too many extended partitions\n");
			}
			break;
		case 0x0b: /* FAT32 */
		case 0x0c: /* FAT32 (LBA) */
                        if (fs_type == 1) {
				found = 1;
				disk.cur_ptable = i;
			}
			break;
		case 0x04: /* FAT16 <32M */
		case 0x06: /* FAT16 */
		case 0x0e: /* FAT16 (LBA) */
                        if (fs_type == 1) {
				found = 1;
				disk.cur_ptable = i;
			}
			break;
		case 0x83: /* Linux */
                        if (fs_type == 0) {
				found = 1;
				disk.cur_ptable = i;
			}
			break;
		default:
			//printf("partition %x: type %x unknown\n", i, disk.ptable[i].type);
			grub_debug("partition unknown type.");
			break;
		}
		if (found)
			break;
	}
	if (!found) {
		grub_error(GRUB_ERR_BAD_PART_TABLE, "No valid partition.\n");
		return 0;
	}
	memset(buffer, 0, 512);

	//disk.total_sectors = nb_sectors; // TODO
	disk.total_sectors = 8388608; // 4 GB size card

	file = grub_file_open(&disk, filename);
	if (file == 0) {
		grub_error(GRUB_ERR_FILE_NOT_FOUND, "Can't open file !");
		return 0;
	}

	int left = file->size;
	int size = 0;
	int pos = 0;
	while (left) {
		if (left > 512)
			size = 512;
		else
			size = left;
		if (grub_file_read(file, buffer + pos, size) != size) {
			grub_error(GRUB_ERR_READ_ERROR, "Can't read file !");
			return 0;
		}
		updateBar1((pos * 100) / (int)file->size);
		pos += size;
		left -= size;
		if (left <= 0)
			break;
	}

	size = file->size;

	grub_file_close(file);

	return size;
}