So!

I have no shortage of ongoing writing projects - I still need to edit and publish the final parts of making our own executable packer, and I’ve recently announced I was working on a Rust book/series. Those are still both on the table.

Buuut… I’m also looking at other things. My best writing happens when I’m learning about something at the same time I’m writing about it. So for example, the Rust book is a bit harder to write, because I’m mostly trying to distill knowledge I’ve already absorbed (for the most part).

In our last article, we managed to load and execute a PIE (position-independent executable) compiled from the following code:

; in `samples/hello-pie.asm` global _start section .text _start: mov rdi, 1 ; stdout fd lea rsi, [rel msg] mov rdx, 9 ; 8 chars + newline mov rax, 1 ; write syscall , , "hi there", 10

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.

A few days ago I posted an ooc quine. But while browing HackerNews, I found an even shorter one. The shortest!

Here it is, in its full glory

Can’t see anything? That’s an empty file. It will compile and run just fine. ooc doesn’t require a main function - you can just shove code in there that will run at the program’s initialization. If there’s none, no big deal! It’ll just not run anything.

ooc makes it easy to compile your application on all major platforms (Windows, OSX, Linux) - the compiler itself runs there, and the SDK supports all these platforms with basic functionality: data structures, file handling, time handling, networking, etc.

But between getting your application running on your dev environment with all the libraries installed, and getting it into a neat package for your users to run without having to install any dependencies by hand, there’s a bag of tricks. Fortunately, I have found the time to figure most of them out. I’ll try to explain these in detail here as clearly as possible, here in this article.

Alright. ALRIGHT. I know, we’re all excited, but let’s think about what we’re doing again.

So we’ve managed to look at real network traffic and parse it completely. We’ve also taken some ICMP packets, parsed them, and then serialized them right back and we got the exact same result.

So I know what you’re thinking - let’s just move our way down the stack again - stuff that ICMP packet in an IP packet, then in an Ethernet frame, and then serialize the whole thing.

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.

Despite their peaceful appearance, game developers actually lead thrilling lives! Here are three things I learned (or re-learned) about yesterday that I’d like to share with you, in the form of assumptions that revealed false.

VSync is relatively straightforward. Right?

As an obsessive-compulsive, bipolar, perfectionist game dev, getting your game to run smoothly on all kinds of operating systems, graphics cards, and drivers combination is something of a holy grail. Many look for it, but let’s be honest here, it never really turns out as expected.

This is going to be a short one.

Basically, since February, both shamanas, fredreichbier and I have putting way too much work into the latest iteration of rock, an ooc compiler written in ooc.

I have the pleasure to announce that version 0.9.7, codename pacino is now out, as you can plainly see on the new website: https://ooc-lang.github.io

You can read the release notes to learn what has changed, but basically expect a lot of fixes, some new APIs, and awesome backtraces.