static int vbr_write(struct exfat_dev* dev)
{
	struct exfat_super_block sb;
	uint32_t checksum;
	le32_t* sector = malloc(get_sector_size());
	size_t i;

	if (sector == NULL)
	{
		exfat_error("failed to allocate sector-sized block of memory");
		return 1;
	}

	init_sb(&sb);
	if (exfat_write(dev, &sb, sizeof(struct exfat_super_block)) < 0)
	{
		free(sector);
		exfat_error("failed to write super block sector");
		return 1;
	}
	checksum = exfat_vbr_start_checksum(&sb, sizeof(struct exfat_super_block));

	memset(sector, 0, get_sector_size());
	sector[get_sector_size() / sizeof(sector[0]) - 1] =
			cpu_to_le32(0xaa550000);
	for (i = 0; i < 8; i++)
	{
		if (exfat_write(dev, sector, get_sector_size()) < 0)
		{
			free(sector);
			exfat_error("failed to write a sector with boot signature");
			return 1;
		}
		checksum = exfat_vbr_add_checksum(sector, get_sector_size(), checksum);
	}

	memset(sector, 0, get_sector_size());
	for (i = 0; i < 2; i++)
	{
		if (exfat_write(dev, sector, get_sector_size()) < 0)
		{
			free(sector);
			exfat_error("failed to write an empty sector");
			return 1;
		}
		checksum = exfat_vbr_add_checksum(sector, get_sector_size(), checksum);
	}

	for (i = 0; i < get_sector_size() / sizeof(sector[0]); i++)
		sector[i] = cpu_to_le32(checksum);
	if (exfat_write(dev, sector, get_sector_size()) < 0)
	{
		free(sector);
		exfat_error("failed to write checksum sector");
		return 1;
	}

	free(sector);
	return 0;
}
Exemple #2
0
static bool verify_vbr_checksum(struct exfat_dev* dev, void* sector,
		fbx_off_t sector_size)
{
	uint32_t vbr_checksum;
	int i;

	if (exfat_pread(dev, sector, sector_size, 0) < 0)
	{
		exfat_error("failed to read boot sector");
		return false;
	}
	vbr_checksum = exfat_vbr_start_checksum(sector, sector_size);
	for (i = 1; i < 11; i++)
	{
		if (exfat_pread(dev, sector, sector_size, i * sector_size) < 0)
		{
			exfat_error("failed to read VBR sector");
			return false;
		}
		vbr_checksum = exfat_vbr_add_checksum(sector, sector_size,
				vbr_checksum);
	}
	if (exfat_pread(dev, sector, sector_size, i * sector_size) < 0)
	{
		exfat_error("failed to read VBR checksum sector");
		return false;
	}
	for (i = 0; i < sector_size / sizeof(vbr_checksum); i++)
		if (le32_to_cpu(((const le32_t*) sector)[i]) != vbr_checksum)
		{
			exfat_error("invalid VBR checksum 0x%x (expected 0x%x)",
					le32_to_cpu(((const le32_t*) sector)[i]), vbr_checksum);
			return false;
		}
	return true;
}