Support 32 bits applications on 64 bits systems

[tobiasBora]

As far as I understand, in most cases 32 bits applications should work on 64 bits systems. However the nixos module creates a single folder /lib64 making it unable to run 32 bits applications.

The discussion was started here #27

[inflation]

Another thing is running x86_64 applications under Rosetta 2 in a VM. I could fetch an x86_64 version of nix-ld and manually symlink to /lib64/ld-linux-x86-64.so.2 and runs the application fine. It would be great to be configurable somehow.

[KoviRobi]

I have something working, see NixOS/nixpkgs#326948

Though nix-ld (as opposed to nix-ld-rs) has an issue with environment variables that are not possible to set:

cannot execute /lib/ld-linux.so.2: You are trying to run an unpatched binary on nixos, but you have not configured NIX_LD or NIX_LD_i686-linux. See https://github.com/Mic92/nix-ld for more details

because of the hyphen-minus (-) which should be an underscore (_), perhaps

https://github.com/Mic92/nix-ld/blob/bf5aa84a713c31d95b4307e442e966d6c7fd7ae7/nix-ld.nix#L22

should use

builtins.replaceStrings ["-"] ["_"] stdenv.system

See also nix-community/nix-ld-rs#67

[Mic92]

Would it help if we would merge nix-ld-rs into nix-ld and make it the new implementation? This was at least my plan.

[KoviRobi]

It would, I'm successfully using nix-ld-rs with 32-bit software, though I just tried and fixing the environment variables also makes this nix-ld work with the nixpkgs patch above. But I certainly understand not wanting to have to maintain both at the same time.

[Mic92]

I merged nix-ld-rs into nix-ld now.

[tobiasBora]

What's the current support for 32 bits applications with nix-ld? I need to run such an application now…

[KoviRobi]

@tobiasBora For now it's not in nixpkgs but you could pick this commit NixOS/nixpkgs#326948 into whichever nixpkgs you use, and then do something like https://github.com/KoviRobi/nixos-config/blob/flake/configurations/base-configuration.nix#L48-L99 (the fact that I need to duplicate the default pkgs is one of the things holding it back, but I haven't got a better way currently)