littlefs2-pack

A Rust crate for building a file system into a LittleFS binary file to be flashed to an embedded device.

This crate wraps the LittleFS C library using the littlefs2-sys crate. The littlefs2 crate might have been an easier starting point but it doesn't currently allow setting the image configuration dynamically at runtime, such as the block size and count.

littlefs2-pack is tested for compatibility with the C++ mklittlefs project. This is ensured with the cross-compat.rs test that packs with one tool then unpack with the other, in both directions. These tests are ran against the version of mklittlefs in the submodule and requires that tool to be built prior to running the tests.

API

The crate can be called directly to create a LittleFS image from a target directory.

use littlefs2_pack::{LfsImage, LfsImageConfig};
let config = LfsImageConfig {
    block_size: 4096,
    block_count: 256,  // 1 MiB total
    read_size: 256,
    write_size: 256,
};
let mut image = LfsImage::new(config).unwrap();
image.format().unwrap();
image.mount_and_then(|fs| {
    fs.create_dir("/data")?;
    fs.write_file("/data/hello.txt", b"Hello from LittleFS!")?;
    Ok(())
}).unwrap();
let binary = image.into_data();
std::fs::write("filesystem.bin", &binary).unwrap();

CLI

The command line interface allows for manually packing, unpacking, and inspecting LittleFS2 images.

Usage: littlefs2-pack <COMMAND>

Commands:
  pack    Pack a directory into a LittleFS2 image
  unpack  Unpack a LittleFS2 image into a directory
  list    List files in a LittleFS2 image
  info    Print info about a LittleFS2 image (block count, used space, etc.)
  help    Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version