Drew DeVault's Blog

When not to use a regex

The other day, I saw Learn regex the easy way. This is a great resource, but I felt the need to pen a post explaining that regexes are usually not the right approach.

State of Sway August 2017

Is it already time to write another one of these? Phew, time flies. Sway marches ever forward. Sway 0.14.0 was recently released, adding much asked-after support for tray icons and fixing some long-standing bugs. As usual, we already have some exciting features slated for 0.15.0 as well, notably some cool improvements to clipboard support. Look forward to it!

Archive it or you will miss it

Let’s open with some quotes from the Wikipedia article on link rot:

An introduction to Wayland

Wayland is the new hotness on the Linux graphics stack. There are plenty of introductions to Wayland that give you the high level details on how the stack is laid out how applications talk directly to the kernel with EGL and so on, but that doesn’t give you much practical knowledge. I’d like to instead share with you details about how the protocol actually works and how you can use it.

Limited "generics" in C without macros or UB

I should start this post off by clarifying that what I have to show you today is not, in fact, generics. However, it’s useful in some situations to solve the same problems that generics might. This is a pattern I’ve started using to reduce the number of void* pointers floating around in my code: multiple definitions of a struct.

Rotating passwords in bulk in the wake of security events

I’ve been putting this post off for a while. Do you remember the CloudFlare security problem that happened a few months ago? This is the one that disclosed huge amounts of sensitive information for huge numbers websites. When this happened, your accounts on thousands of websites were potentially compromised.

Building a "real" Linux distro

I recently saw a post on Hacker News: “Build yourself a Linux”, a cool project that guides you through building a simple Linux system. It’s similar to Linux from Scratch in that it helps you build a simple Linux system for personal use. I’d like to supplement this with some insight into my experience with a more difficult task: building a full blown Linux distribution. The result is agunix, the “silver unix” system.

State of Sway April 2017

Development on Sway continues. I thought we would have slowed down a lot more by now, but every release still comes with new features - Sway 0.12 added redshift support and binary space partitioning layouts. Sway 0.13.0 is coming soon and includes, among other things, nvidia proprietary driver support. We already have some interesting features slated for Sway 0.14.0, too!

MSG_PEEK is pretty common, CVE-2016-10229 is worse than you think

I heard about CVE-2016-10229 earlier today. In a nutshell, it allows for arbitrary code execution via UDP traffic if userspace programs are using MSG_PEEK in their recv calls. I quickly updated my kernels and rebooted any boxes where necessary, but when I read the discussions on this matter I saw people downplaying this issue by claiming MSG_PEEK is an obscure feature.

Principles for C programming

In the words of Doug Gwyn, “Unix was not designed to stop you from doing stupid things, because that would also stop you from doing clever things”. C is a very powerful tool, but it is to be used with care and discipline. Learning this discipline is well worth the effort, because C is one of the best programming languages ever made. A disciplined C programmer will…