mirage/ocaml-mbr

Name: ocaml-mbr

Owner: MirageOS

Description: A simple library for manipulating Master Boot Records

Created: 2013-11-01 15:19:53.0

Updated: 2017-12-08 00:54:02.0

Pushed: 2015-06-04 16:21:40.0

Homepage: null

Size: 365

Language: OCaml

GitHub Committers

User	Most Recent Commit	# Commits

Other Committers

User	Email	Most Recent Commit	# Commits

README

ocaml-mbr

A simple library for manipulating Master Boot Records. The primary purposes of this library are:

1. to create bootable disk images creating mirage kernels
2. for mirage kernels to read the partition tables on attached disks

Usage

Define a single partition as follows:

let disk_length_bytes = Int32.(mul (mul 16l 1024l) 1024l) in
let disk_length_sectors = Int32.(div disk_length_bytes 512l) in

let start_sector = 2048l in
let length_sectors = Int32.sub disk_length_sectors start_sector in
let partition = Mbr.Partition.make ~active:true ~ty:6 start_sector length_sectors in
let mbr = Mbr.make [ partition ] in

You can write the MBR to sector zero of a block device `B` as follows:

B.connect id >>|= fun device ->
let sector = Cstruct.create 512 in
Mbr.marshal sector mbr;
B.write device 0L [ sector ] >>|= fun () ->

You can then create a Partition block device as follows:

let module Partition = Mbr_partition.Make(B) in
Partition.connect {
  Partition.b = device;
  start_sector = Int64.of_int32 start_sector;
  length_sectors = Int64.of_int32 length_sectors;
} >>= fun partition_or_error ->

To do items

• It's easy to specify nonsense, for example overlapping partition entries. We could do with a way to represent a disk as a set of non-overlapping extents which could be nested (partition / LVM volume / filesystem / file)