In our last installment of “Making our own executable packer”, we did some code cleanups. We got rid of a bunch of unsafe code, and found a way to represent memory-mapped data structures safely.

But that article was merely a break in our otherwise colorful saga of “trying to get as many executables to run with our own dynamic loader”. The last thing we got running was the ifunc-nolibc program.

Day, 10! Day, 10!

Okay, Day 10.

Again, the problem statement is very confusing - but what it all boils down to is this. We have a list of numbers:

16 10 15 5 1 11 7 19 6 12 4

To which we need to add 0 and whatever the maximum was, plus three:

16 10 15 5 1 11 7 19 6 12 4 0 22

From there on, if we take them in order, we’ll have gaps of 1 and gaps of 3:

Note: this article is adapted from a presentation I gave at a Rust Paris Meetup — that’s why it sounds a little different than usual. Enjoy!

Good evening! Tonight, I will attempt to answer the question: Does Dioxus spark joy? Or at the very least, whimsy.

What’s Dioxus, you ask? It is first and foremost a name that is quote: “legally not inspired by any Pokémon”.

I use the draw.io desktop app to make diagrams for my website. I run it on an actual desktop, like Windows or macOS, but the asset pipeline that converts .drawio files, to .pdf, to .svg, and then to .svg again (but smaller) runs on Linux.

So I have a Rust program somewhere that opens headless chromium, and loads just the HTML/JS/CSS part of draw.io I need to render my diagrams, and then use Chromium’s “print to PDF” functionality to save a PDF.

Background

I recently had a bit of impromptu disaster recovery, and it gave me a hunger for more! More downtime! More kubernetes manifest! More DNS! Ahhhh!

The plan was really simple. I love dedicated Hetzner servers with all my heart but they are not very fungible.

You have to wait entire minutes for a new dedicated server to be provisioned. Sometimes you pay a setup fee, et cetera. And at some point to server static websites and serve as a K3S server, it’s simply just too big, and approximately twice the price that I should pay.

So, how does ping.exe actually send a ping? It seems unrealistic that ping.exe itself implements all the protocols involved in sending a ping. So it must be calling some sort of library. Also, since it ends up talking to the outside world via a NIC (network interface controller), the kernel is probably involved at some point.

In reading files the hard way - part 2, we learned about dynamic libraries (like libc), and the Linux kernel, and how syscalls allowed us to ask the Linux kernel to do our bidding. For this series, we’re going to have to look at the Windows equivalents.

It happened when I least expected it.

Someone, somewhere (above me, presumably) made a decision. “From now on”, they declared, “all our new stuff must be written in Rust”.

I’m not sure where they got that idea from. Maybe they’ve been reading propaganda. Maybe they fell prey to some confident asshole, and convinced themselves that Rust was the answer to their problems.

Now that our development environment is all set up, let’s make something useful!

Creating the catscii crate

From a VS Code window connected to our VM (as we just set up), let’s make a new Rust project:

amos@miles:~$ cargo new catscii Created binary (application) `catscii` package

And open it in a new VSCode window:

amos@miles:~$ code catscii

In hours, I have played more of The Binding of Isaac than any other game in my Steam library. Edmund McMillen said he wasn’t expecting it to be a hit, and has since proceeded to be proven thoroughly wrong.

It is kind of a big deal among a certain crowd: as I’m writing this, the second season of the Binding of Isaac Racing League, hosted and commented by Crumps, is in full swing - even though the game was certainly not designed for that!

Part 1

Let’s tackle the day 4 challenge!

In this one, we get an input like this:

2-4,6-8 2-3,4-5 5-7,7-9 2-8,3-7 6-6,4-6 2-6,4-8

Each line has two ranges: the first line has ranges containing 2, 3, 4, and 6, 7, 8. We must count how many pairs have ranges where one fully contains the other.

In Rust, we can express this with “inclusive ranges” (std::ops::RangeInclusive), and those implement Iterator, so we can do: