Natalie

but MathWorks have a Docker Container, which seemed like a good way to not have it destroy my system. and it was!!! downloading stuff took ages. whatever. expected that, plus it's cached so i'm not angry yet. one problem.

the6p4c@dragonfruit
20:00  ~> docker run -it --rm -e DISPLAY=$DISPLAY \ 
    -v /tmp/.X11-unix:/tmp/.X11-unix:ro --shm-size=512M \ 
    mathworks/matlab:r2023a

Running matlab

Starting MATLAB with license: [blah blah] - MATLAB (Individual)
[dear reader: pause here for about
10 minutes to simulate the issue]

so that's annoying. why's it so slow to launch?? i tried not using --rm to see if it was a first-boot thing, but it happened every time, no matter what i did or didn't do.

we have a puzzle to solve

#reverse engineering #this post took like three hours to write please help me

bark. bark bark @bark8/1/2023, 12:01 AM

as a side note

i write over-complicated css to give you merely half the vibe of having a conversation with me. all over the place, a complete mess, and somehow emoji everywhere

Jessica @ticky8/3/2023, 6:28 AM

sorry I wasn’t listening I was closing a thousand million file descriptors

@nex3 shared with:

#code

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in reply to @bark's post:

shuppy @delan7/31/2023, 3:49 PM

beautiful

bark. bark bark @bark7/31/2023, 3:51 PM

🐶💜

@lexi7/31/2023, 3:58 PM

a) what the fuck
b) i would never have figured that out, incredible work
c) time to check the page again

iliana @iliana8/3/2023, 6:32 AM

OH MY GOD i had to fix this exact issue in an unrelated RPM shell script trigger years ago because yum installs were hanging or some doofus shit but only in docker containers

Vikxin @vikxin8/3/2023, 10:05 AM

Have these people not heard of FD_CLOEXEC? It exists specifically so you don't have to do stuff like this.

Vikxin @vikxin8/3/2023, 10:23 AM

I'm also not sure why it seems to be catching an error thrown after generating a UUID fails due to a lack of entropy (maybe? wonder if it's trying to read /dev/random and that's not mapped into the Docker container) and ... launching a new process while handling that? It is a mystery.

bark. bark bark @bark8/3/2023, 3:20 PM

ah, so, since it’s a mostly stripped binary, the symbols in the stack trace are just the only things with names before the actual address - hence the really big offsets at the end since the actual code is nowhere near those few functions with symbols. that tripped me up at first too

Vikxin @vikxin8/3/2023, 6:03 PM

Oh, yes, I've encountered that before, but also I was like 2/3 asleep when I posted that and didn't even notice how gigantic the offsets were

chell @alterae8/3/2023, 2:25 PM

okay genuine question bc i am definitely missing something here:
why is it closing file descriptors? especially file descriptors it isn’t using? what does this accomplish??? why not simply not do that????

bark. bark bark @bark8/3/2023, 3:22 PM

it’s in the process of cleaning up in a process it just forked, afaict - so it’s closing all the fds which were used in the parent process so they don’t hang around in the new child

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