glibc_version_header VS musl-cross-make

One major headache with trying to run precompiled binaries on Linux is that if they were compiled using a newer version of glibc than the target machine, they won't be able to run. Back while working on Factorio, I was trying to get around this problem with endless Docker containers, but coworker Wheybags came up with a much solution to this, which is simply to, at compile time, link to the oldest compatible version of glibc: https://github.com/wheybags/glibc_version_header

If what you're doing works for you, great, but in case it stops working at some point (or if for some reason you need to build on a current-gen distro version), you could also consider using this:

https://github.com/wheybags/glibc_version_header

It's a set of autogenerated headers that use symbol aliasing to allow you to build against your current version of glibc, but link to the proper older versioned symbols such that it will run on whatever oldest version of glibc you select.

There are other approaches like https://github.com/wheybags/glibc_version_header or sysroots with older glibc, e.g. https://wiki.gentoo.org/wiki/Crossdev - you don't need your whole XP, just the the system libs to link against.

Sure, having a nice SDK where you can just specify the minimum vesion you want to support would be nice but who do you expect to develop such an SDK? GNU/glibc maintainers? They would rather you ship as source. Red Hat / SUSE / Canonical? They want you to target only their distro. Valve? They decided its easier to just provide an unchaning set of libraries since they need to support existing games that got things wrong anyway and already have a distribution platform to distribute such a base system along with the games without bundling it into every single one.

A few links gathered from a quick google search as a primer:

http://stevehanov.ca/blog/?id=97

https://www.evanjones.ca/portable-linux-binaries.html

https://insanecoding.blogspot.com/2012/07/creating-portable-...

https://rpg.hamsterrepublic.com/ohrrpgce/Portable_GNU-Linux_...

https://github.com/wheybags/glibc_version_header

In other words: there are a lot of steps and a lot of gotchyas to doing this that you're glossing over. Linux userland libraries are generally designed with the intention that an army of third-party maintainers will integrate all of this desperately developed software together and place it in a repo. Naturally every distribution wants to do things a little differently too, and they have a habit of changing it up every couple years. When you try to step out of that mold things unsurprisingly become more difficult. Whereas Windows, Mac, Android, etc. have been designed since the beginning not to require that sort of thing and it is consequently a much, much more straightforward process.

I'm curious why, since you seem to believe the process is so straight-forward, you think it is that so few people distribute a simple binary? Why were Flatpak and AppImage invented?

> Binaries compiled against today's glibc can fail to run on a machine that hasn't been updated since last week because they rely on a new / different symbol.

Note, however, that it is a Glibc bug (modulo Drepper’s temper) if the reverse happens: Glibc symbol versioning ensures that binaries depending on an old Glibc (only) will run on a new one. So the proper way to build a maximally-compatible Linux executable would be to build a cross toolchain targeting an old Glibc and compile your code with it. Unfortunately, the build system is hell and old Glibcs doesn’t compile without backported patches, so while I did try to follow in the footsteps of a couple of people[1–4], I did not succeed.

Mass-rebuilds still happen with other ecosystems, though. GHC-compiled Haskell libraries are fine-grained and not ABI-stable across compiler versions, so my Arch box regularly gets hit with a deluge of teensy library updates, and Arch is currently undergoing a massive Python rebuild (blocking all other Python package updates) behind the scenes as well.

[1]: https://github.com/wheybags/glibc_version_header (hack but easy and will probably work most of the time)

I've done the same alpine trick for static binaries but may I introduce you to musl-cross-make?

https://github.com/richfelker/musl-cross-make

Just burned out static toolchains that make me static binaries for all architectures gcc supports. Much like musl.cc but they suggest building your own and I do.

I use these toolchains on debian (/ anywhere a non-ancient linux kernel runs) to make static binaries, you can too!

Python obviously isn't 14kb because its code is divided into hundreds of shared object files. So the way I like to measure things is using static executable size, using tools like https://github.com/jart/cosmopolitan or https://github.com/richfelker/musl-cross-make of which you'll find a static build in the cosmo repo. For example, here's the technique I used to build TinyLISP was something like this:

I have a different issue with ring. This is on a custom Cortex A9 board at work. For most depedencies I can get compilation working fine with armv7-unknown-linux-musleabihf. I was able to build the cross compiler using https://github.com/richfelker/musl-cross-make , adding

A bit off topic, I hope someday GCC's build system gets overhauled. A huge advantage of LLVM is that it is quite easier to rebuild the runtime libraries without rebuilding the compiler. With GCC that's a pain, unless one takes the time to re-package GCC very carefully like https://github.com/richfelker/musl-cross-make and https://exherbo.org/.

Maybe getting some new GCC devs in there with projects like this would help with that?