Building proot is not automated about nix-on-droid

[t184256]

Oh god, I pulled it off! I've cross-compiled a proot that works!

Everybody with even a bit of Nix knowledge is welcome to my proot.nix to fix my sloppy cross-compiling (seriously, I've cut a lot of corners on that way, like, all of them).

Everybody with aarch64 devices is kindly asked to wipe+reinstall (or substitute proot) and go for another hunt for the dreaded bus error.

it may be useful: NixOS/nixpkgs@52566c3 (not yet merged)

[t184256]

Mindlessly tried building

pkgsCross.aarch64-multiplatform.pkgsStatic.proot
.overrideAttrs (oa: {
  version = "2019-03-12";
  src = pkgs.fetchFromGitHub {
    repo = "proot";
    owner = "termux";
    rev = "09568e21ff9fee7a6907be34a2d0fde3bacca7eb";
    sha256 = "1091si4i07349y7x7sx1r904gg3c9a3m39xkv24fakjlirpi3lpy";
  };
  makeFlags = [ "-Csrc CFLAGS=-D__ANDROID__" ];
}))
.override {
  enablePython = false;
)

from that checkout, got a proot that dies with a Bus Error on a very early mkdir.

[matthewbauer]

Hmm... it's possible that the proot fork only works with bionic? That gets trickier because we don't have a good way to cross execute android linker. Something like this should work:

let
  pkgs = import <nixpkgs> {
    crossSystem = (import <nixpkgs/lib>).systems.examples.aarch64-multiplatform-musl;
    crossOverlays = [ (import <nixpkgs/pkgs/top-level/static.nix>) ];
  };
  proot = pkgs.proot.override { enablePython = false; };
in pkgs.runCommand "test" {} ''
  ${pkgs.stdenv.hostPlatform.emulator pkgs.buildPackages} ${proot}/bin/proot --version
''

but there's obviously some things specific to android that could be causing the bus error.

[t184256]

Interesting, maybe I do need bionic.

Did I understand your suggestion correctly: build proot statically, but use aarch64-android-prebuilt (and not aarch64-multiplatform-musl like in your example) to get it statically linked against bionic?

[matthewbauer]

Yeah, Musl should work with Android fine after all it is just linux. But it's definitely possible something is causing an issue.