Comment by exabrial
9 hours ago
I think this looks incredible. Like how does one create a compatible abi _for all of linux_??? Wow!
> utilize the more productive Rust programming language
Nitpick: it’s 2024 and these ‘more productive’ comparisons are silly, completely unscientific, And a bit of a red flag for your project: The most productive language for a developer is the one they understand what is happening one layer below the level of abstraction they are working with. Unless you’re comparing something rating Ruby vs RiscV assembly, it’s just hocus-pocus.
> I think this looks incredible. Like how does one create a compatible abi _for all of linux_??? Wow!
FWIW that’s what the Linux compatibility layer in the BSDs does and also what WSL 1 did (https://jmmv.dev/2020/11/wsl-lost-potential.html).
It’s hard to get _everything_ perfectly right but not that difficult to get most of it working.
IIRC Fuschia has something similar. And maybe Redox?
> Like how does one create a compatible abi _for all of linux_???
You look at Linux's syscall table[0], read through the documentation to figure out the arguments, data types, flags, return values, etc., and then implement that in your kernel. The Linux ABI is just its "library" interface to userspace.
It's probably not that difficult; writing the rest of the kernel itself is more challenging, and, frankly, more interesting. Certainly matching behavior and semantics can be tricky sometimes, I'm sure. And I wouldn't be surprised if the initial implementation of some things (like io_uring, for example, if it's even supported yet) might be primitive and poorly optimized, or might even use other syscalls to do their work.
But it's doable. While Linux's internal ABI is unstable, the syscall interface is sacred. One of Torvalds' golden rules is you don't break userspace.
[0] https://filippo.io/linux-syscall-table/
Everyone says what they are used to is better or more productive. Even in assembly vs ruby, some stuff are much easier in assembly and maybe impossible in ruby afaik
I’m aging myself, but ~17 years ago I was in San Diego for a conference. There was a table level competition to see who could write the fastest program in 20 minutes (we were doing a full text search of a ‘giant’ 5g file). One of the guys at the table wrote some SPARC assembly to optimize character matching that was a hotspot like he was speaking French.
Ah good times.