FAT32-Raw 🚀

A fully featured Rust library for direct work with FAT32 partitions and images. Provides low-level access to the FAT32 file system with support for reading, writing, creating and deleting files and directories.

✨ Key features

🎯 Core capabilities

• Direct partition access: Native support for ESP (EFI System Partition), SD cards, USB flash drives
• Cross‑platform: Full support for Windows and Linux with handling of OS‑specific nuances
• Full FAT32 feature set: Read, write, create, delete files and directories
• Nested directories: Support for creating and navigating deeply nested directory structures
• Long file names (LFN): Full Unicode name support up to 255 characters
• Auto parameter detection: Automatic parsing of BPB (BIOS Parameter Block)

🔧 Technical advantages

• Safety: Minimal use of unsafe code, strong typing
• Performance: Optimized read/write operations with buffering
• Reliability: Proper error handling, protection against data corruption
• Windows specifics: Solves access rights issues (OS Error 5) via special file opening flags

🚀 Quick start

Working with a disk image

use fat32_raw::Fat32Volume;

fn main() -> std::io::Result<()> {
    // Open a FAT32 image
    let mut volume = Fat32Volume::open_esp(Some("esp.img"))?
        .expect("Failed to open FAT32 image");

    // Create directories
    volume.create_dir_lfn("config")?;
    
    // Create and write a file
    volume.create_file_lfn("test.txt")?;
    let content = b"Hello from fat32-raw!";
    volume.write_file("test.txt", content)?;
    
    // Read the file back
    if let Some(data) = volume.read_file("test.txt")? {
        println!("Content: {}", String::from_utf8_lossy(&data));
    }
    
    // Delete the file
    volume.delete_file_lfn("test.txt")?;
    
    Ok(())
}

Working with a real ESP partition

use fat32_raw::Fat32Volume;

fn main() -> std::io::Result<()> {
    // Automatic search and opening of the ESP partition
    // On Windows, administrator rights are required
    // On Linux, sudo may be required
    let mut volume = Fat32Volume::open_esp(None::<&str>)?
        .expect("ESP partition not found");
    
    // Work with the partition the same way as with an image
    volume.create_dir_lfn("MyApp")?;
    volume.create_file_lfn("MyApp_config.txt")?;
    volume.write_file("MyApp_config.txt", b"Configuration")?;
    
    // List files in the root
    let entries = volume.list_root()?;
    for entry in entries {
        println!("{} - {}", 
            entry.name, 
            if entry.is_directory { "DIR" } else { "FILE" }
        );
    }
    
    Ok(())
}

📦 Installation

Add to Cargo.toml:

[dependencies]
fat32-raw = "1.0"

🧪 Testing

The project includes a test suite that covers all operations:

# Run regular tests
cargo test

# Run tests on a real ESP (requires sudo/Administrator)
# WARNING: this test works with a real ESP partition!
sudo cargo test --test real_esp_test

🏗️ Project structure

fat32-raw/
├── src/
│   ├── lib.rs              # Main library module
│   ├── error.rs            # Error handling
│   ├── fat32/
│   │   ├── mod.rs          # FAT32 module
│   │   ├── volume.rs       # Core volume logic
│   │   ├── directory.rs    # Directory operations
│   │   ├── file.rs         # File operations
│   │   ├── fat_table.rs    # FAT table handling
│   │   ├── lfn.rs          # Long file name support
│   │   └── utils.rs        # Helper functions
│   └── platform/
│       ├── mod.rs          # Platform abstractions
│       ├── windows/        # Windows‑specific code
│       └── unix/           # Unix/Linux‑specific code
└── tests/
    └── real_esp_test.rs    # Integration tests with real ESP

🚧 Roadmap

• Support for creating and deleting files and directories
• Automatic ESP partition discovery on disks
• Working with nested directories
• Full integration with Windows and Linux
• Handling access rights issues on Windows
• ⏳ MBR partition support
• ⏳ Defragmentation and optimization
• ⏳ FAT12/FAT16 support
• ⏳ Integration with GitHub Actions CI/CD

🤝 Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a branch for your changes
3. Make sure all tests pass
4. Open a pull request

📄 License

This project is distributed under the GPLv3 license.

🙏 Acknowledgements

• The Rust community for great tools and documentation
• The authors of the FAT32 specification from Microsoft
• All project contributors and users