patchelf

Ah you can use https://github.com/NixOS/patchelf/pull/564 So you can do e.g. `patchelf --remove-needed-version libm.so.6 GLIBC_2.29 ./mybinary` instead of replacing glibc wholesale (step 2 and 3) and assuming all of used glibc by the executable is ABI compatible this will just work (it's worked for a small binary for me, YMMV).

OP would probably have a field day with NixOS's patchelf tool: https://github.com/NixOS/patchelf

I mean, we don't have to hack the elf loader if we just rewrite every elf binary using patchelf: https://github.com/NixOS/patchelf The parent commenter is already suggesting "just run a regex", so it seems like a trivial extension to their simple solution to "just run patchelf on every binary on your system"

How does an article on NixOS talk about the `rpath` issue without also mentioning the `patchelf` utility that NixOS developers created to solve this issue? It's a small tool that lets you modify ELF executables and binaries. It's also the recommended way for NixOS users to modify binaries to work properly. https://github.com/NixOS/patchelf

Yeah, and thanks to Nix you can use PatchELF[0] to change the rpath on a binary too. Point being that for users it is not a straight-forward process to make a Linux application portable. Thanks to Linux Desktop's lackadaisical approach to userspace ABI compatibility it isn't necessarily that easy for developers either. [0] https://github.com/NixOS/patchelf

Yes, exactly: https://github.com/NixOS/patchelf It's a key part of how nix works.

Patchelf is almost always broken, and when they merge fixes they don't release a new version right away. Between 2014-2019 running patchelf+strip would corrupt binaries, after the fix running patchelf twice on the same binary would corrupt it. And now patchelf doesn't work on all binaries, there's a bugfix merged https://github.com/NixOS/patchelf/pull/230 merged Nov 19, 2020, but no release since then. Also patchelf exposed a bug in ldconfig noted 11 years ago and only fixed in glibc 2.31: https://nix-dev.science.uu.narkive.com/q6Ww5fyO/ldconfig-pro... And currently patchelf still has a bug: https://github.com/NixOS/patchelf/pull/275 Apparently elf files are hard.

> but it doesn't prevent you from linking the problematic program directly with libfoobar-1.0.3 I feel that patchelf[0] is an ingenious little tool for exactly that purpose that isn't getting enough love. Not as useful for FOSS stuff, but it's been really useful for the times I had to relink proprietary things on our cluster in order to patch a security vulnerability or two. [0] https://github.com/NixOS/patchelf

I had the same experience as well. I tried NixOS once as my main desktop environment. I encountered two problems that made me switch to Ubuntu+Nix. And they work perfectly for their own purposes. One problem is dynamically linked binaries, where the library points to a global position (like /usr/lib). In NixOS, different builds can depend on different versions of the same binary, so there is no single global location. This is not necessarily a bad thing in itself. And normal cases can be fixed with the patchelf [^1] utility. I couldn't make it work with a Z3 binary, so I finally gave up. The other problem is when I tried to configure jackdbus. There's only one example [^2] configuration. It is marked as outdated by the wiki, and indeed none of the settings work for me. Then I realized these two are not problems that Nix tries to solve. Po

> Say I happen to install package X via apt and Y via nix, and both of them depend on Z (in apt and nix respectively) That actually is impossible, Nix will only depend on packages in nix, and nothing else. So whatever you have installed won't affect it. The important part of Nix on Linux is patchelf[1] basically binaries generated are processed by it, this rewrites elfs to link to libraries in the /nix/store Regarding syscalls, if you use NixOS then you're tied to specific state of nixpkgs, which also dictates the kernel installed. So you shouldn't run into it. You probably might run if you install Nix on Ubuntu. I don't remember running into it, and I think it should be rare since linux ABI supposed to not break compatibility. [1] https://github.com/NixOS/patchelf

If you ever need to tweak or inspect an existing binary, https://github.com/NixOS/patchelf is great.

The execution environment for a product is certainly reproducible with Docker, assuming you actually make your base image Dockerfile work in a reproducible environment as well. You can also use Dockerfiles as units of deployment for individual software projects, which offers that. While it is true that NixOS offers a different vision for how to solve these problems, it does so in a way I find very destructive for actual use. It seems inferior for deploying software compared to containerization (which offers immutable and composable build artifacts), and very cumbersome to work with during software development (since the value of writing nix packages during development is cumbersome and for many language environments you have to deploy the source code in the package and compile it within the closure you expect to deploy on to make any head