Inspect an MBR or GPT image

[dependencies.hadris]
version = "3.0.0-rc.2"
default-features = false
features = ["std", "sync", "part"]

use hadris::part::sync::read;
use hadris::part::{PartitionKind, PartitionTable};
use hadris::storage::host::FileDevice;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut disk = FileDevice::open("disk.img")?;
    let table = read(&mut disk)?;

    if let PartitionTable::Gpt(gpt) = table.table() {
        if let Some(copy) = gpt.damaged_copy() {
            println!("the {copy:?} GPT is damaged; writing the table repairs it");
        }
    }
    for partition in table.partitions() {
        let kind = match partition.kind() {
            PartitionKind::Mbr(kind) => kind.to_string(),
            PartitionKind::Gpt(guid) => guid.to_string(),
            _ => String::from("unknown"),
        };
        let name = partition.name().map(|n| n.to_string()).unwrap_or_default();
        println!(
            "#{}: block {} ({} blocks, {} bytes) {kind} {name}",
            partition.slot(),
            partition.start(),
            partition.len(),
            partition.size_bytes(),
        );
    }

    Ok(())
}

The block size comes from the device. host::FileDevice queries physical devices and defaults regular image files to 512-byte blocks. For an image copied from a 4Kn disk, use FileDevice::open_with_block_size(path, BlockSize::new(4096).unwrap()). A hadris::storage::sync::StreamDevice also takes an explicit block size. GPT CRCs are always checked; when the primary copy is damaged the table is read from the backup, and damaged_copy says so. Slots are zero-based: MBR primary partitions use slots 0 to 3 and logical partitions in an extended partition follow from slot 4, so Linux numbers are one higher (slot 4 is sda5). Disk::partition(slot) takes the same zero-based slot that Partition::slot reports, not a Linux partition number.

Without an allocator, hadris::part::sync::scan lists the same partitions through a callback. To open a filesystem inside one of them, see Open FAT inside a partition.