Astro Hacker News - Show HN: A (marginally) useful x86-64 ELF executable in 301 bytes

vparseval |next [-]

Love it! It's entirely inapplicable and useless to me but it embodies the spirit of Show HN and what the spirit of programming in the 80s and 90s was.

captn3m0 |next |previous [-]

I have a use for this: A somewhat portable one-liner to go in my waybar/sway/i3 configs!

emanuele-em |next |previous [-]

301 bytes! The base64 one-liner install is a nice flex. Accepting an infinite loop when energy_full doesn't exist is peak code golf, perfectly reasonable when every byte counts. Is there a writeup on the assembly somewhere?

billforsternz |root |parent |next [-]

I would prefer avoiding the infinite loop and printing a message to help the user understand what went wrong. I'm sure you could do that with an extra 100 bytes or so. Just my opinion of course.

zahlman |root |parent |next |previous [-]

The xz step doesn't seem to be doing very much, though. It seems the decoded data is currently 278 bytes versus a 298-byte decompressed result.

sjdv1982 |root |parent |previous [-]

Haha this is great!

What about adding a Make rule to auto-generate the one-liner install from the binary?

bregma |next |previous [-]

As always with these admirable hacks, I feel compelled to point out these are not really ELF executables but just small files you can trick the x86_64 Linux kernel into loading.

I mean they're very clever and legit and kudos to the people who develop these exploits, but they're not ELF.

noam_k |root |parent [-]

Is it really not ELF? The file starts with the \x7FELF magic, but I'm not by my laptop to see what `file btry` outputs.

userbinator |next |previous [-]

It doesn't even look like particularly optimised Asm (could immediately spot a few savings, despite how horrible GAS syntax is to read...), but is definitely not "compiler slop"[1] either, which shows just how inefficient the majority of programs actually are. Of course even the ELF header takes up a significant amount of space, but this reminds me of how PC magazines would print short listings of utilities like this, often a few dozen up to a few hundred bytes at most --- in DOS .COM format, which is headerless and thus pure machine instructions.

[1] In the late 80s and early 90s, the battle between those writing handwritten Asm and those using compiled HLLs has many similarities to AI-generated vs non-AI code today.

meribold |root |parent [-]

If the savings are about `mov $1, %edi` and `mov $10, %ecx`, those 32-bit immediate values line up with the higher bytes of p_filesz and p_memsz in the program header, which have to be zero [1]. If not, what are the savings? :)

[1]: https://github.com/meribold/btry/commit/8ef5a4ce58ae73c489d2...

Eric_Xua |next |previous [-]

Love this kind of tiny, over‑engineered hack—totally impractical, but pure Show HN energy.

darioterror |previous [-]

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