block-device-id

A Rust library and command-line tool to retrieve hardware-innate unique identifiers from block devices, such as MMC CID or NVME controller serial numbers. These identifiers are suitable for use in cryptographic key derivation or device-specific configuration.

Features

• C-compatible shared library interface
• Command-line tool for querying device identifiers
• Supports multiple block device types (MMC, NVME, etc.)
• Debian-native package with vendored dependencies

Building

Standard Build

To build the Debian package normally:

debuild -b -uc -us

Network-Isolated Build with bwrap

This is a Debian-native Rust package that uses vendored Debian versions of packages rather than fetching from crates.io. For network-isolated builds (e.g., in build environments without internet access), you can use bwrap (bubblewrap) to create an isolated build environment.

Prerequisites

• bwrap must be installed
• A resolv.conf file must be present in the project root (or create one for DNS resolution if needed)

Build Command

bwrap --bind / / --bind ./resolv.conf /etc/resolv.conf --dev /dev --proc /proc -- debuild -b -uc -us

This command:

• --bind / / - Binds the root filesystem
• --bind ./resolv.conf /etc/resolv.conf - Uses a local resolv.conf file (prevents DNS lookups)
• --dev /dev - Provides access to device files
• --proc /proc - Provides access to /proc filesystem
• -- debuild -b -uc -us - Runs the Debian build process

Creating resolv.conf

If you don't have a resolv.conf file, you can create a minimal one:

echo "nameserver 127.0.0.1" > resolv.conf

Or copy your system's resolv.conf:

cp /etc/resolv.conf ./resolv.conf

Note: The resolv.conf file is used to prevent DNS resolution attempts during the build. Even with a non-functional nameserver, the build will work because all dependencies are vendored and no network access is required.

How It Works

The build process uses Debian's dh-cargo which:

1. Sets up a vendored cargo registry from /usr/share/cargo/registry
2. Creates a config.toml in debian/cargo_home/ that replaces crates.io with the local registry
3. Pre-generates cargo metadata for cbindgen to avoid network access
4. Uses cbindgen with the pre-generated metadata to create C headers

All Rust dependencies are provided by Debian packages (e.g., librust-libc-dev, librust-nix-dev, etc.), so no network access to crates.io is needed.

Package Structure

• block-device-id - Command-line tool
• libblockdeviceid1 - Shared library (C-compatible)
• libblockdeviceid-dev - Development files (headers, examples)
• librust-block-device-id-dev - Rust source package

Usage

Command Line

block-device-id /dev/mmcblk0

C API

See examples/get_device_id.c for a complete example.

#include <block_device_id.h>

char id[129];
int ret = bdi_get_id("/dev/nvme0n1", id, sizeof(id));
if (ret == 0) {
    printf("Device ID: %s\n", id);
}

License

BSD-3-Clause - See LICENSE file for details.