iso9660-rs

A pure no_std ISO9660 filesystem implementation in Rust with El Torito bootable CD support.

Features

• Pure no_std - Works in bare metal, UEFI bootloaders, and embedded environments
• ISO9660 Level 1/2/3 - Full ECMA-119 standard support
• El Torito - Bootable CD/DVD parsing for kernel extraction from live ISOs
• Rock Ridge - POSIX extensions for permissions and symlinks (optional feature)
• Joliet - Long Unicode filename support (optional feature)
• Zero-copy parsing - Efficient direct parsing from block devices
• Minimal dependencies - Only gpt_disk_io for block device abstraction

Use Cases

• UEFI bootloaders that boot Linux from ISO files on ESP
• Embedded systems booting from CD-ROM or ISO images
• Hypervisors/VMs mounting ISOs for guest boot
• Recovery tools reading from optical media
• ISO inspection in no_std contexts

Installation

[dependencies]
iso9660-rs = "1.0.1"

For optional extensions:

[dependencies]
iso9660-rs = { version = "1.0.1", features = ["rock-ridge", "joliet"] }

Quick Start

use iso9660::{mount, find_file, read_file, find_boot_image};

// Mount ISO from block device
let volume = mount(&mut block_io, 0)?;

// Find and read a file
let file = find_file(&mut block_io, &volume, "/boot/vmlinuz")?;
let mut buffer = vec![0u8; file.size as usize];
read_file(&mut block_io, &file, &mut buffer)?;

// Extract bootable image via El Torito
let boot = find_boot_image(&mut block_io, &volume)?;
println!("Boot image at sector {}, {} bytes", boot.load_rba, boot.sector_count * 512);

API Overview

High-Level Functions

Advanced APIs

Typical Usage Pattern

use iso9660::{mount, find_file, read_file, FileReader};

// 1. Mount ISO
let volume = mount(&mut block_io, 0)?;

// 2. Find file by path
let file = find_file(&mut block_io, &volume, "/boot/vmlinuz")?;

// 3. Option A: Read entire file into vector
let data = iso9660::read_file_vec(&mut block_io, &file)?;

// Option B: Stream read with buffer
let mut buf = [0u8; 4096];
let bytes_read = read_file(&mut block_io, &file, &mut buf)?;

// Option C: Use FileReader for advanced control
let mut reader = FileReader::new(&file);
reader.seek(512)?;  // Skip first sector
let pos = reader.position();

Architecture

iso9660/
├── volume/        # Volume descriptor parsing (Primary, Supplementary, Boot)
├── directory/     # Directory record navigation and iteration
├── file/          # File reading from extents
├── boot/          # El Torito boot catalog parsing
├── extensions/    # Rock Ridge, Joliet (optional)
└── utils/         # Datetime, string conversion, checksums

El Torito Boot Support

Extract bootable images from live ISO files - essential for UEFI bootloaders booting Tails, Ubuntu, etc.:

use iso9660::find_boot_image;

// Find boot image
let boot = find_boot_image(&mut block_io, &volume)?;

// Access boot image metadata
println!("Boot platform: {:?}", boot.platform);      // x86, EFI, PowerPC, Mac
println!("Media type: {:?}", boot.media_type);        // NoEmulation, Floppy, HardDisk, CDROM
println!("Boot location: sector {}", boot.load_rba);  // Sector number
println!("Boot size: {} bytes", boot.sector_count * 512);  // Size in 512-byte sectors

Spec Compliance

Based on ECMA-119 (ISO 9660:1988) and El Torito (1995) specifications.

Supported

• ✅ Primary Volume Descriptor
• ✅ Directory tree navigation
• ✅ Both-endian field handling
• ✅ File version stripping (;1)
• ✅ El Torito validation + initial entry
• ✅ 7-byte and 17-byte datetime formats

Optional (feature flags)

• 🔧 Rock Ridge POSIX extensions (rock-ridge)
• 🔧 Joliet Unicode filenames (joliet)

Minimum Supported Rust Version

Rust 1.70 or later.

License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE)
• MIT license (LICENSE-MIT)

at your option.

Contributing

Contributions welcome! This crate aims to be a reliable foundation for low-level systems work. Please keep changes focused and include tests where possible.