DCMD_BLK_PARTENTRY

Get the partition entry

Synopsis:

#include <sys/dcmd_blk.h>

#define DCMD_BLK_PARTENTRY    __DIOF(_DCMD_BLK, 1, struct partition_entry)

Arguments to devctl():

Argument	Value
`filedes`	A file descriptor that you obtained by opening the device.
`dcmd`	DCMD_BLK_PARTENTRY
`dev_data_ptr`	A pointer to a struct partition_entry that the device can fill in (see below)
`n_bytes`	`sizeof(struct partition_entry)`
`dev_info_ptr`	NULL

Description:

This command gets the partition entry for the device associated with the given file descriptor. It's used by x86 disk partitions with harddisk-based filesystems.

Input:

None.

Output:

The struct partition_entry (or partition_entry_t) is defined in <sys/disk.h> as follows:

typedef struct partition_entry {
    unsigned char   boot_ind,
                    beg_head,
                    beg_sector,
                    beg_cylinder,
                    os_type,
                    end_head,
                    end_sector,
                    end_cylinder;
    uint32_t        part_offset,
                    part_size;
} partition_entry_t;

The members include:

boot_ind: 0x80 if the partition is bootable, 0x00 if it isn't.
beg_head: The beginning head number.
beg_sector: The beginning sector number.
beg_cylinder: The beginning cylinder number.
os_type: The partition type; see “Partitions” in the Filesystems chapter of the System Architecture guide.
end_head: The end head number.
end_sector: The end sector number.
end_cylinder: The end cylinder number.
part_offset: The offset of the partition, in bytes.
part_size: The number of sectors in the partition.

Example:

partition_entry_t *prt;

memset(&prt, 0, sizeof(prt));
if(devctl(fd, DCMD_BLK_PARTENTRY, prt, sizeof(*prt), 0) == EOK) {
   ...
}