static void extended_partition(struct gendisk *hd, struct block_device *bdev,
int minor, unsigned long first_size, int *current_minor)
{
struct partition *p;
Sector sect;
unsigned char *data;
unsigned long first_sector, this_sector, this_size;
int mask = (1 << hd->minor_shift) - 1;
int sector_size = get_hardsect_size(to_kdev_t(bdev->bd_dev)) / 512;
int loopct = 0; /* number of links followed
without finding a data partition */
int i;
this_sector = first_sector = hd->part[minor].start_sect;
this_size = first_size;
while (1) {
if (++loopct > 100)
return;
if ((*current_minor & mask) == 0)
return;
data = read_dev_sector(bdev, this_sector, §);
if (!data)
return;
if (!msdos_magic_present(data + 510))
goto done;
p = (struct partition *) (data + 0x1be);
/*
* Usually, the first entry is the real data partition,
* the 2nd entry is the next extended partition, or empty,
* and the 3rd and 4th entries are unused.
* However, DRDOS sometimes has the extended partition as
* the first entry (when the data partition is empty),
* and OS/2 seems to use all four entries.
*/
/*
* First process the data partition(s)
*/
for (i=0; i<4; i++, p++) {
unsigned long offs, size, next;
if (!NR_SECTS(p) || is_extended_partition(p))
continue;
/* Check the 3rd and 4th entries -
these sometimes contain random garbage */
offs = START_SECT(p)*sector_size;
size = NR_SECTS(p)*sector_size;
next = this_sector + offs;
if (i >= 2) {
if (offs + size > this_size)
continue;
if (next < first_sector)
continue;
if (next + size > first_sector + first_size)
continue;
}
add_gd_partition(hd, *current_minor, next, size);
#if CONFIG_BLK_DEV_MD
if (SYS_IND(p) == LINUX_RAID_PARTITION) {
md_autodetect_dev(MKDEV(hd->major,*current_minor));
}
#endif
(*current_minor)++;
loopct = 0;
if ((*current_minor & mask) == 0)
goto done;
}
/*
* Next, process the (first) extended partition, if present.
* (So far, there seems to be no reason to make
* extended_partition() recursive and allow a tree
* of extended partitions.)
* It should be a link to the next logical partition.
* Create a minor for this just long enough to get the next
* partition table. The minor will be reused for the next
* data partition.
*/
p -= 4;
for (i=0; i<4; i++, p++)
if (NR_SECTS(p) && is_extended_partition(p))
break;
if (i == 4)
goto done; /* nothing left to do */
this_sector = first_sector + START_SECT(p) * sector_size;
this_size = NR_SECTS(p) * sector_size;
minor = *current_minor;
put_dev_sector(sect);
}
done:
put_dev_sector(sect);
}
int msdos_partition(struct gendisk *hd, struct block_device *bdev,
unsigned long first_sector, int first_part_minor)
{
int i, minor = first_part_minor;
Sector sect;
struct partition *p;
unsigned char *data;
int mask = (1 << hd->minor_shift) - 1;
int sector_size = get_hardsect_size(to_kdev_t(bdev->bd_dev)) / 512;
int current_minor = first_part_minor;
int err;
err = handle_ide_mess(bdev);
if (err <= 0)
return err;
data = read_dev_sector(bdev, 0, §);
if (!data)
return -1;
if (!msdos_magic_present(data + 510)) {
put_dev_sector(sect);
return 0;
}
p = (struct partition *) (data + 0x1be);
/*
* Look for partitions in two passes:
* First find the primary and DOS-type extended partitions.
* On the second pass look inside *BSD, Unixware and Solaris partitions.
*/
current_minor += 4;
for (i=1 ; i<=4 ; minor++,i++,p++) {
if (!NR_SECTS(p))
continue;
add_gd_partition(hd, minor,
first_sector+START_SECT(p)*sector_size,
NR_SECTS(p)*sector_size);
#if CONFIG_BLK_DEV_MD
if (SYS_IND(p) == LINUX_RAID_PARTITION) {
md_autodetect_dev(MKDEV(hd->major,minor));
}
#endif
if (is_extended_partition(p)) {
unsigned long size = hd->part[minor].nr_sects;
printk(" <");
/* prevent someone doing mkfs or mkswap on an
extended partition, but leave room for LILO */
if (size > 2)
hd->part[minor].nr_sects = 2;
extended_partition(hd, bdev, minor, size, ¤t_minor);
printk(" >");
}
}
/*
* Check for old-style Disk Manager partition table
*/
if (msdos_magic_present(data + 0xfc)) {
p = (struct partition *) (0x1be + data);
for (i = 4 ; i < 16 ; i++, current_minor++) {
p--;
if ((current_minor & mask) == 0)
break;
if (!(START_SECT(p) && NR_SECTS(p)))
continue;
add_gd_partition(hd, current_minor, START_SECT(p), NR_SECTS(p));
}
}
printk("\n");
/* second pass - output for each on a separate line */
minor -= 4;
p = (struct partition *) (0x1be + data);
for (i=1 ; i<=4 ; minor++,i++,p++) {
unsigned char id = SYS_IND(p);
int n;
if (!NR_SECTS(p))
continue;
for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++)
;
if (subtypes[n].parse)
subtypes[n].parse(hd, bdev, minor, ¤t_minor);
}
put_dev_sector(sect);
return 1;
}
int msdos_partition(struct gendisk *hd, struct block_device *bdev,
unsigned long first_sector, int first_part_minor)
{
int i, minor = first_part_minor;
Sector sect;
struct partition *p;
unsigned char *data;
int mask = (1 << hd->minor_shift) - 1;
int sector_size = get_hardsect_size(to_kdev_t(bdev->bd_dev)) / 512;
int current_minor = first_part_minor;
int err;
#ifdef CONFIG_IDE_IPOD
int sector_mult = 1;
#endif
err = handle_ide_mess(bdev);
if (err <= 0)
return err;
data = read_dev_sector(bdev, 0, §);
if (!data)
return -1;
if (!msdos_magic_present(data + 510)) {
put_dev_sector(sect);
return 0;
}
p = (struct partition *) (data + 0x1be);
#ifdef CONFIG_IDE_IPOD
/*
* Addition for iPods: check for actual filesystems to figure out the correct partition layout
*/
for (i=1 ; i<=4 ; i++,p++) {
unsigned char *partdata;
if (!NR_SECTS(p))
continue;
if (SYS_IND(p) == 0xb) {
partdata = read_dev_sector(bdev, first_sector+START_SECT(p)*sector_size*4, §);
if (msdos_magic_present(partdata + 510))
sector_mult = 4;
partdata = read_dev_sector(bdev, first_sector+START_SECT(p)*sector_size*2, §);
if (msdos_magic_present(partdata + 510))
sector_mult = 2;
partdata = read_dev_sector(bdev, first_sector+START_SECT(p)*sector_size, §);
if (msdos_magic_present(partdata + 510))
sector_mult = 1;
} else if (SYS_IND(p) == 0x83) {
partdata = read_dev_sector(bdev, first_sector+START_SECT(p)*sector_size*4+2, §);
if (ext3_magic_present(partdata + 56))
sector_mult = 4;
partdata = read_dev_sector(bdev, first_sector+START_SECT(p)*sector_size*2+2, §);
if (ext3_magic_present(partdata + 56))
sector_mult = 2;
partdata = read_dev_sector(bdev, first_sector+START_SECT(p)*sector_size+2, §);
if (ext3_magic_present(partdata + 56))
sector_mult = 1;
}
}
printk("Experimental partition and filesystem detection code by Vincent Huisman ([email protected])\n");
printk("Partition sector size: %d\n", sector_mult);
sector_size *= sector_mult;
p = (struct partition *) (data + 0x1be); // Reinitialize, duh
#endif
/*
* Look for partitions in two passes:
* First find the primary and DOS-type extended partitions.
* On the second pass look inside *BSD, Unixware and Solaris partitions.
*/
current_minor += 4;
for (i=1 ; i<=4 ; minor++,i++,p++) {
if (!NR_SECTS(p))
continue;
add_gd_partition(hd, minor,
first_sector+START_SECT(p)*sector_size,
NR_SECTS(p)*sector_size);
#if CONFIG_BLK_DEV_MD
if (SYS_IND(p) == LINUX_RAID_PARTITION) {
md_autodetect_dev(MKDEV(hd->major,minor));
}
#endif
if (is_extended_partition(p)) {
unsigned long size = hd->part[minor].nr_sects;
printk(" <");
/* prevent someone doing mkfs or mkswap on an
extended partition, but leave room for LILO */
if (size > 2)
hd->part[minor].nr_sects = 2;
extended_partition(hd, bdev, minor, size, ¤t_minor);
printk(" >");
}
}
/*
* Check for old-style Disk Manager partition table
*/
if (msdos_magic_present(data + 0xfc)) {
p = (struct partition *) (0x1be + data);
for (i = 4 ; i < 16 ; i++, current_minor++) {
p--;
if ((current_minor & mask) == 0)
break;
if (!(START_SECT(p) && NR_SECTS(p)))
continue;
add_gd_partition(hd, current_minor, START_SECT(p), NR_SECTS(p));
}
}
printk("\n");
/* second pass - output for each on a separate line */
minor -= 4;
p = (struct partition *) (0x1be + data);
for (i=1 ; i<=4 ; minor++,i++,p++) {
unsigned char id = SYS_IND(p);
int n;
if (!NR_SECTS(p))
continue;
for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++)
;
if (subtypes[n].parse)
subtypes[n].parse(hd, bdev, minor, ¤t_minor);
}
put_dev_sector(sect);
return 1;
}
