backhand

Library and binaries for the reading, creating, and modification of SquashFS file systems.

Library

Add the following to your Cargo.toml file:

[dependencies]
backhand = "0.9.1"

Reading/Writing/Modifying Firmware

use std::fs::File;
use std::io::Cursor;
use backhand::{FilesystemReader, FilesystemWriter, NodeHeader};

// read
let file = File::open("file.squashfs").unwrap();
let read_filesystem = FilesystemReader::from_reader(file).unwrap();

// convert to writer
let mut write_filesystem = FilesystemWriter::from_fs_reader(&read_filesystem).unwrap();

// add file with data from slice
let d = NodeHeader::default();
let bytes = Cursor::new(b"Fear is the mind-killer.");
write_filesystem.push_file(bytes, "a/d/e/new_file", d);

// add file with data from file
let new_file = File::open("dune").unwrap();
write_filesystem.push_file(new_file, "/root/dune", d);

// modify file
let bytes = Cursor::new(b"The sleeper must awaken.\n");
write_filesystem.replace_file("/a/b/c/d/e/first_file", bytes).unwrap();

// write into a new file
let mut output = File::create("modified.squashfs").unwrap();
write_filesystem.write(&mut output).unwrap();

Testing

This library is tested with unpacking and packing SquashFS firmwares and testing that result with unsquashfs. openwrt binaries are primarily being tested.

Binaries

These are currently under development and are missing features, MR's welcome!

To install, run cargo install backhand.

unsquashfs

tool to uncompress, extract and list squashfs filesystems

Usage: unsquashfs [OPTIONS] <FILESYSTEM>

Arguments:
  <FILESYSTEM>  Squashfs file

Options:
  -o, --offset <BYTES>   Skip BYTES at the start of FILESYSTEM [default: 0]
  -l, --list             List filesystem, do not write to DEST
  -d, --dest <PATHNAME>  Extract to [PATHNAME] [default: squashfs-root]
  -i, --info             Print files as they are extracted
  -f, --force            If file already exists then overwrite
  -s, --stat             Display filesystem superblock information
  -h, --help             Print help information
  -V, --version          Print version information

add

tool to add files to squashfs filesystems

Usage: add <FILESYSTEM> <FILE> <FILE_PATH>

Arguments:
  <FILESYSTEM>  Squashfs file
  <FILE>
  <FILE_PATH>

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