rustup requires newer GLIBC than rustc on some arches

[cuviper]

Problem
The distributed builds of rustup on some arches require relatively recent GLIBC symbols, newer than the baseline used by rustc itself. Especially, those that build rustup with ubuntu:18.04 cross-gcc will be tied to a similar OS ABI, while rustc supports older systems than that.

This bug is a continuation of #1339.

Steps
For example, on RHEL 7.6 ppc64:

$ rpm -q glibc
glibc-2.17-260.el7.ppc64
$ curl https://sh.rustup.rs -sSf | sh
info: downloading installer
/tmp/tmp.VElBcOx0vj/rustup-init: /lib64/libc.so.6: version `GLIBC_2.25' not found (required by /tmp/tmp.VElBcOx0vj/rustup-init)
/tmp/tmp.VElBcOx0vj/rustup-init: /lib64/libc.so.6: version `GLIBC_2.18' not found (required by /tmp/tmp.VElBcOx0vj/rustup-init)

Possible Solution(s)
Rust's own docker images use careful cross toolchains to maintain ABI, and I think rustup could just reuse those same docker images.

Notes
For the currently available linux-gnu binaries, I see:

$ for f in */rustup-init; do echo $f; eu-readelf -V $f | grep -o 'Name: GLIBC\S*' | sort -V | tail -n1; done
aarch64-unknown-linux-gnu/rustup-init
Name: GLIBC_2.17
arm-unknown-linux-gnueabihf/rustup-init
Name: GLIBC_2.16
arm-unknown-linux-gnueabi/rustup-init
Name: GLIBC_2.16
armv7-unknown-linux-gnueabihf/rustup-init
Name: GLIBC_2.16
i686-unknown-linux-gnu/rustup-init
Name: GLIBC_2.3.4
mips64el-unknown-linux-gnuabi64/rustup-init
Name: GLIBC_2.25
mips64-unknown-linux-gnuabi64/rustup-init
Name: GLIBC_2.25
mipsel-unknown-linux-gnu/rustup-init
Name: GLIBC_2.25
mips-unknown-linux-gnu/rustup-init
Name: GLIBC_2.25
powerpc64le-unknown-linux-gnu/rustup-init
Name: GLIBC_2.25
powerpc64-unknown-linux-gnu/rustup-init
Name: GLIBC_2.25
powerpc-unknown-linux-gnu/rustup-init
Name: GLIBC_2.25
s390x-unknown-linux-gnu/rustup-init
Name: GLIBC_2.25
x86_64-unknown-linux-gnu/rustup-init
Name: GLIBC_2.3.4

All of those requiring GLIBC_2.25 are problematic: mips, powerpc, and s390x.

Rust currently uses ubuntu:16.04 toolchains for all mips* targets, RHEL6-ish toolchains for powerpc, powerpc64, and s390x, and RHEL7-ish toolchains for powerpc64le.

[kinnison]

Thanks for your report @cuviper - I guess that what we need to do is to consider the base docker images we use for our builds. Currently we simply use trusty but perhaps there's a still-supported Ubuntu option we might use instead? Otherwise I guess we need to customise the dist for each architecture.

If you could take a look at .travis.yml and make a suggestion (or even better, a PR) then I'd appreciate your input.

Thanks,

D.

[mati865]

Trusty (Ubuntu 16.04) will reach EOL on 17.04.2019 so this workaround will be temporary. Also it ships with glibc 2.19 so binaries still would not work on RHEL or CentOS.

[nrc]

I think that for non-tier 1 platforms, you're best course of action is to build from source. We would happily accept a PR if needed to help with that, but I don't think we have the bandwidth to improve things for our own distributions, sorry.

[cuviper]

I'm intending to work on this, if you could leave it open...

[cuviper]

The symbol versions for those arches look much better in the rustup 1.18 release:

$ for f in */rustup-init; do echo $f; eu-readelf -V $f | grep -o 'Name: GLIBC\S*' | sort -V | tail -n1; done
mips64el-unknown-linux-gnuabi64/rustup-init
Name: GLIBC_2.18
mips64-unknown-linux-gnuabi64/rustup-init
Name: GLIBC_2.18
mipsel-unknown-linux-gnu/rustup-init
Name: GLIBC_2.18
mips-unknown-linux-gnu/rustup-init
Name: GLIBC_2.18
powerpc64le-unknown-linux-gnu/rustup-init
Name: GLIBC_2.17
powerpc64-unknown-linux-gnu/rustup-init
Name: GLIBC_2.7
powerpc-unknown-linux-gnu/rustup-init
Name: GLIBC_2.7
s390x-unknown-linux-gnu/rustup-init
Name: GLIBC_2.7

[matthiasdiener]

Thanks @cuviper! I can confirm that installation on CentOS 7 ppc64le works out of the box now, without requiring the script I had mentioned in #1339.