rustup-init.sh does not correctly detect host string for Pinebook Pro

[NoraCodes]

Problem
On Pinebook Pro Debian stretch (9.9), rustup-init.sh tries to download rustup-init for aarch64, but that doesn't work; the CPU is ARMv8. Even once I downloaded an armv7 rustup-init, it guessed the wrong target triple.

Possible Solution(s)
Instead of just checking uname, check the actual ld library; on my machine this is only ld-linux-armhf.so.3 and therefore it is detectable that any aarch64 binaries won't run.

[kinnison]

Can you please confirm the output of uname -s, uname -m and dpkg --print-architecture ?

[NoraCodes]

uname -s: Linux
uname -m: aarch64
dpkg --print-architecture: armhf

[kinnison]

Okay, that's fascinating. I suppose it might be similar to someone running an amd64 kernel and a 32 bit userland, but without running it under a 32 bit personality. Hmm.

Perhaps we could add a check via getconf LONG_BIT which should return 32 for you (if you can confirm?)

[NoraCodes]

LONG_BIT does indeed report 32, yeah.

[tesuji]

But is getconf portable enough?

[kinnison]

I'd only be suggesting the use of getconf when diagnosing a linux system which reports amd64 or aarch64 since those are the natively bi-arch options I think. Others need personality switches IIRC
So it'd be a disambiguation step, not something run everywhere. As for where it comes from -- on Debian it's in libc-bin so I'm guessing it's part of the set of things glibc tends to have. No idea if musl would have it, but we could simply say that if getconf can't run, we assume same bitness as the kernel personality reported.

[kinnison]

@NoraCodes Short term fix for you would be to download rustup-init.sh and then run it with: linux32 sh rustup-init.sh -- that should get you the right rustup etc.

[NoraCodes]

Thank you, that worked well.

[kinnison]

Okay cool, so @NoraCodes can at least get on with Rust on her Pinebook, and I have an idea for how we might resolve this for future users.

[kinnison]

If anyone wishes to approach this, please let me know here, or via Discord in the #wg-rustup channel.

[kinnison]

@NoraCodes Could you please try https://raw.githubusercontent.com/kinnison/rustup.rs/kinnison/32bit-linux-on-64bit-kernel/rustup-init.sh which contains the little fix I think we need for this? All you need do is download it, and run it and see if it fetches the right installer. If it doesn't, please run it sh -x rustup-init.sh look for where it starts to inspect /proc/self/exe and copy/paste from there to where it starts downloading the installer, so that I can diagnose better.

[NoraCodes]

I am away from my PBP at the moment but I will do this tomorrow. Thanks for the prompt attention!

[NoraCodes]

Sorry that "tomorrow" became Wednesday :/

In any case, I get an error that https://static.rust-lang.org/rustup/dist/armv7-unknown-linux-gnu/rustup-init is 404ing, but that looks like the right decision to download!

[kinnison]

@NoraCodes Hmm, 404 seems odd, but we're getting somewhere (It's wanting to change its decision a bit) I'll have a rummage and see what I've missed...

<fx: time-passes>

I've pushed a fix to that branch, I wasn't taking into account the fact that armv7 non-android has an ABI suffix. Could you give that same link a fresh go? If it works then we're sorted.

[NoraCodes]

Works perfectly, thank you!

[kinnison]

Fabulous, thank you for the testing. I shall file a PR soon.