Expand description
A library that allows managing MBR partition tables.
Features
- Create primary partitions and logical volumes
- Delete primary partitions and logical volumes
- Automatically generate logical volume’s EBR (or can be provided manually)
- If the disk geometry is set, the partition CHS addresses will be calculated automatically when writing to disk
Examples
Read all the partitions of a disk
let mut f = std::fs::File::open("tests/fixtures/disk1.img")
.expect("could not open disk");
let mbr = mbrman::MBR::read_from(&mut f, 512)
.expect("could not find MBR");
println!("Disk signature: {:?}", mbr.header.disk_signature);
for (i, p) in mbr.iter() {
// NOTE: The first four partitions are always provided by iter()
if p.is_used() {
println!("Partition #{}: type = {:?}, size = {} bytes, starting lba = {}",
i,
p.sys,
p.sectors * mbr.sector_size,
p.starting_lba);
}
}
Create and delete primary partitions
let mut f = std::fs::File::open("tests/fixtures/disk1.img")
.expect("could not open disk");
let mut mbr = mbrman::MBR::read_from(&mut f, 512)
.expect("could not find MBR");
let free_partition_number = mbr.iter().find(|(i, p)| p.is_unused()).map(|(i, _)| i)
.expect("no more places available");
let sectors = mbr.get_maximum_partition_size()
.expect("no more space available");
let starting_lba = mbr.find_optimal_place(sectors)
.expect("could not find a place to put the partition");
mbr[free_partition_number] = mbrman::MBRPartitionEntry {
boot: mbrman::BOOT_INACTIVE, // boot flag
first_chs: mbrman::CHS::empty(), // first CHS address (only useful for old computers)
sys: 0x83, // Linux filesystem
last_chs: mbrman::CHS::empty(), // last CHS address (only useful for old computers)
starting_lba, // the sector where the partition starts
sectors, // the number of sectors in that partition
};
mbr[free_partition_number] = mbrman::MBRPartitionEntry::empty();
// NOTE: no modification is committed to the disk until we call mbr.write_into()
Create a new partition table from an empty disk
let ss = 512; // sector size
let data = vec![0; 100 * ss as usize];
let mut cur = std::io::Cursor::new(data);
let mut mbr = mbrman::MBR::new_from(&mut cur, ss as u32, [0xff; 4])
.expect("could not create partition table");
// NOTE: commit the change to the in-memory buffer
mbr.write_into(&mut cur);
Add a new logical volume to the disk
let ss = 512; // sector size
let data = vec![0; 100 * ss as usize];
let mut cur = std::io::Cursor::new(data);
let mut mbr = mbrman::MBR::new_from(&mut cur, ss as u32, [0xff; 4])
.expect("could not create partition table");
mbr[1] = mbrman::MBRPartitionEntry {
boot: mbrman::BOOT_INACTIVE, // boot flag
first_chs: mbrman::CHS::empty(), // first CHS address (only useful for old computers)
sys: 0x0f, // extended partition with LBA
last_chs: mbrman::CHS::empty(), // last CHS address (only useful for old computers)
starting_lba: 1, // the sector where the partition starts
sectors: mbr.disk_size - 1, // the number of sectors in that partition
};
// this helper function will do all the hard work for you
// here it creates a logical volume with Linux filesystem that occupies the entire disk
// NOTE: you will lose 1 sector because it is used by the EBR
mbr.push(0x83, 1, mbr.disk_size - 1);
// NOTE: commit the change to the in-memory buffer
mbr.write_into(&mut cur);
Add a new logical volume manually to the disk
This is useful only if you need to specify exactly where goes the EBR and the partition itself.
let ss = 512; // sector size
let data = vec![0; 100 * ss as usize];
let mut cur = std::io::Cursor::new(data);
let mut mbr = mbrman::MBR::new_from(&mut cur, ss as u32, [0xff; 4])
.expect("could not create partition table");
mbr[1] = mbrman::MBRPartitionEntry {
boot: mbrman::BOOT_INACTIVE, // boot flag
first_chs: mbrman::CHS::empty(), // first CHS address (only useful for old computers)
sys: 0x0f, // extended partition with LBA
last_chs: mbrman::CHS::empty(), // last CHS address (only useful for old computers)
starting_lba: 1, // the sector where the partition starts
sectors: mbr.disk_size - 1, // the number of sectors in that partition
};
// NOTE: mbrman won't check the consistency of the partition you have created manually
mbr.logical_partitions.push(
mbrman::LogicalPartition {
// this is the actual partition entry for the logical volume
partition: mbrman::MBRPartitionEntry {
boot: mbrman::BOOT_INACTIVE,
first_chs: mbrman::CHS::empty(),
sys: 0x83,
last_chs: mbrman::CHS::empty(),
starting_lba: 2, // the sector index 1 is used by the EBR
sectors: mbr.disk_size - 2,
},
// this is the absolute LBA address of the EBR
absolute_ebr_lba: 1,
// the number of sectors in the first EBR is never known
ebr_sectors: None,
// empty boot sector in the EBR
bootstrap_code: [0; 446],
// this is the absolute CHS address of the EBR (only used by old computers)
ebr_first_chs: mbrman::CHS::empty(), // only for old computers
// this is the absolute CHS address of the last EBR (only used by old computers)
// NOTE: this is not know the first EBR
ebr_last_chs: None,
}
);
// NOTE: commit the change to the in-memory buffer
mbr.write_into(&mut cur);
Structs
- A CHS address (cylinder/head/sector)
- An abstraction struct for a logical partition
- A type representing a MBR partition table including its partition, the sector size of the disk and the alignment of the partitions to the sectors.
- An MBR partition table header
- An MBR partition entry
Enums
- An error
Constants
- Boot flag for a bootable partition
- Boot flag for a non-bootable partition
Type Definitions
- The result of reading, writing or managing a MBR.