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/* This function performs three tasks:
- Make sectors disk relative from partition relative.
- Normalize offset to be less than the sector size.
- Verify that the range is inside the partition. */
static grub_err_t
grub_disk_adjust_range (grub_disk_t disk, grub_disk_addr_t *sector,
grub_off_t *offset, grub_size_t size)
{
grub_partition_t part;
grub_disk_addr_t total_sectors;
*sector += *offset >> GRUB_DISK_SECTOR_BITS;
*offset &= GRUB_DISK_SECTOR_SIZE - 1;
for (part = disk->partition; part; part = part->parent)
{
grub_disk_addr_t start;
grub_uint64_t len;
start = part->start;
len = part->len;
if (*sector >= len
|| len - *sector < ((*offset + size + GRUB_DISK_SECTOR_SIZE - 1)
>> GRUB_DISK_SECTOR_BITS))
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("attempt to read or write outside of partition"));
*sector += start;
}
/* Transform total_sectors to number of 512B blocks. */
total_sectors = disk->total_sectors << (disk->log_sector_size - GRUB_DISK_SECTOR_BITS);
/*
* Some drivers have problems with disks above reasonable sizes.
* Clamp the size to GRUB_DISK_MAX_SECTORS. Just one condition is enough
* since GRUB_DISK_SIZE_UNKNOWN is always above GRUB_DISK_MAX_SECTORS,
* assuming a maximum 4 KiB sector size.
*/
if (total_sectors > GRUB_DISK_MAX_SECTORS)
total_sectors = GRUB_DISK_MAX_SECTORS;
if ((total_sectors <= *sector
|| ((*offset + size + GRUB_DISK_SECTOR_SIZE - 1)
>> GRUB_DISK_SECTOR_BITS) > total_sectors - *sector))
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("attempt to read or write outside of disk `%s'"), disk->name);
return GRUB_ERR_NONE;
}
static inline grub_disk_addr_t
transform_sector (grub_disk_t disk, grub_disk_addr_t sector)
{
return sector >> (disk->log_sector_size - GRUB_DISK_SECTOR_BITS);
}
static unsigned
grub_disk_cache_get_index (unsigned long dev_id, unsigned long disk_id,
grub_disk_addr_t sector)
{
return ((dev_id * 524287UL + disk_id * 2606459UL
+ ((unsigned) (sector >> GRUB_DISK_CACHE_BITS)))
% GRUB_DISK_CACHE_NUM);
}
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