The Python package linux-utils provides utility functions that make it easy to script system administration tasks on Linux systems in Python. The following functionality is currently implemented:

• Parsing of the /etc/fstab and /etc/crypttab configuration files.
• A basic Python API for cryptsetup and a Python implementation of cryptdisks_start and cryptdisks_stop (with a command line interface).
• Atomic filesystem operations for Linux in Python.
• Simple network location awareness / discovery.

The package is currently tested on cPython 2.7, 3.4, 3.5, 3.6, 3.7 and PyPy (2.7) on Ubuntu Linux (using Travis CI).

The linux-utils package is available on PyPI which means installation should be as simple as:

$ pip install linux-utils

There's actually a multitude of ways to install Python packages (e.g. the per user site-packages directory, virtual environments or just installing system wide) and I have no intention of getting into that discussion here, so if this intimidates you then read up on your options before returning to these instructions 😉.

For details about the Python API please refer to the API documentation available on Read the Docs. The Python implementation of cryptdisks_start and cryptdisks_stop is available on the command line as the following two programs:

As the names imply these programs are not functional equivalents of their "official" counterparts, because they only support LUKS encryption and a small subset of the available encryption options.

Usage: cryptdisks-start-fallback NAME

Reads /etc/crypttab and unlocks the encrypted filesystem with the given NAME.

This program emulates the functionality of Debian's cryptdisks_start program, but it only supports LUKS encryption and a small subset of the available encryption options.

Usage: cryptdisks-stop-fallback NAME

Reads /etc/crypttab and locks the encrypted filesystem with the given NAME.

This program emulates the functionality of Debian's cryptdisks_stop program, but it only supports LUKS encryption and a small subset of the available encryption options.

Back in 2015 I wrote some Python code to parse the Linux configuration files /etc/fstab and /etc/crypttab for use in crypto-drive-manager. Fast forward to 2017 and I found myself wanting to use the same functionality in rsync-system-backup. Three options presented themselves to me:

Copy/paste the relevant code

Having to maintain the same code in multiple places causes lower quality code because having to duplicate the effort of writing documentation, developing tests and fixing bugs is a very demotivating endeavor. In fact sometime in 2016 I did copy/paste parts of this code into a project at work, because I needed similar functionality there. Of course since then the two implementations have started diverging 😛.

Make crypto-drive-manager a dependency of rsync-system-backup

Although this approach is less ugly than copy/pasting the code, it still isn't exactly elegant because the two projects have nothing to do with each other apart from working with LUKS encrypted disks on Linux.

Extract the functionality into a new package

In my opinion this is clearly the most elegant approach, unfortunately it also requires the most work from me 😇. On the plus side I'm publishing the new package with a test suite which means less untested code remains in crypto-drive-manager (which doesn't have a test suite at the time of writing).

While extracting the code I shortly considered integrating the functionality into debuntu-tools, however the /etc/fstab and /etc/crypttab parsing isn't specific to Debian or Ubuntu at all and debuntu-tools has several dependencies that aren't relevant to Linux configuration file parsing.

Since then it has become clear that this was a good choice (not merging the functionality into debuntu-tools) because linux-utils now provides a Python implementation of cryptdisks_start and cryptdisks_stop, which is mostly useful on Linux systems that aren't based on Debian 🙂.

The latest version of linux-utils is available on PyPI and GitHub. The documentation is available on Read the Docs and includes a changelog. For bug reports please create an issue on GitHub. If you have questions, suggestions, etc. feel free to send me an e-mail at peter@peterodding.com.

This software is licensed under the MIT license.

© 2020 Peter Odding.