py-uboot-env 0.1.2

A package for reading, modifying, and writing U-Boot environment files

py-uboot-env

A Python package for manipulating U-Boot environment files with a modern API and convenient CLI tools.

Overview

py-uboot-env provides functionality to read, modify, and write U-Boot environment files. It features both a programmer-friendly API and a versatile command-line interface.

Features

• Command-line interface for common operations
• Support for both file paths and file handles
• Environment variable dependency analysis and visualization
• Built-in environment editor with your system's default text editor

Installation

Install from PyPI:

pip install py-uboot-env

API Usage

Basic Usage

from py_uboot_env import load_env

# Load an environment file
env = load_env('/path/to/uboot.env')

# Read values
bootcmd = env.get('bootcmd')
bootdelay = env.get('bootdelay', '3')  # With default value

# Modify values
env.set('bootdelay', '5')
env.delete('unused_var')

# Save changes
env.save('/path/to/uboot.env')

Working with File Handles

from py_uboot_env import load_env, dump_env
import io

# Create an in-memory file-like object
buffer = io.BytesIO()

# Create a new environment and save it to the buffer
env = load_env(existing_env_file)
env.set('new_variable', 'value')
dump_env(env, buffer)

# Rewind the buffer and read it back
buffer.seek(0)
updated_env = load_env(buffer)

Command-Line Interface

py-uboot-env provides a single uboot-env command with multiple actions:

Viewing Environment Variables

# Dump the entire environment
uboot-env dump /path/to/uboot.env

# Get a specific variable
uboot-env get /path/to/uboot.env bootcmd

Modifying Environment Variables

# Set a variable
uboot-env set /path/to/uboot.env bootdelay 5

# Delete a variable
uboot-env delete /path/to/uboot.env unused_var

Interactive Editing

Open the environment file in your default text editor:

uboot-env edit /path/to/uboot.env

Dependency Analysis

Generate a GraphViz DOT representation of variable dependencies:

# Generate DOT output
uboot-env graph /path/to/uboot.env > uboot-deps.dot

# Generate a PDF using GraphViz (if installed)
uboot-env graph /path/to/uboot.env | dot -Tpdf -o uboot-deps.pdf

This analyzes which environment variables are read from, written to, or which commands are run by each variable, creating a visual dependency graph.

Environment File Format

The package handles U-Boot environment files in their standard binary format, including:

• CRC32 checksums in the header
• Support for different environment sizes
• Proper handling of redundant environment blocks

Development

Testing

The package includes a comprehensive test suite to ensure functionality and reliability.

Running Tests

To run the test suite, first install pytest:

pip install pytest

Then run the tests:

python -m pytest

For more detailed output, use the verbose flag:

python -m pytest -v

Test Coverage

The test suite covers:

• Core Functionality: Tests for the UBootEnv class methods (get, set, delete, save) and utility functions (load_env, dump_env, format_env).
• Error Handling: Tests for handling invalid environment sizes and CRC errors.
• CLI Commands: Tests for all environment manipulation commands (dump, get, set, delete, edit).
• Integration Tests: End-to-end workflows for both API and CLI usage patterns.

Contributing

1. Fork the repository
2. Create a feature branch
3. Submit a pull request

License

This project is licensed under The Unlicense - see the LICENSE file for details.

Acknowledgments

• U-Boot Project
• Original code by Dave Jones which served as the foundation for this package