Documentation: describe how to programatically obtain host paths on NixOS

2 files changed, 33 insertions, 0 deletions

diff --git a/README.md b/README.md
index 5124a71..c8b618e 100644
--- a/README.md
+++ b/README.md
@@ -227,6 +227,9 @@ Example configuration for bootstrapping on NixOS (hashes may vary):
 }
 ~~~
 
+On NixOS, the host configuration is most easily obtained using a custom derivation
+obtained from a simple [host-configuration package](doc/host-config.nix).
+
 ## Musl Performance Issues
 
 Musl has huge allocator contention issues with multithreading. For that reason,
diff --git a/doc/host-config.nix b/doc/host-config.nix
new file mode 100644
index 0000000..340598e
--- /dev/null
+++ b/doc/host-config.nix
@@ -0,0 +1,30 @@
+{ stdenv
+, jo
+, coreutils
+, gnused
+, glibc
+}:
+
+stdenv.mkDerivation rec  {
+  name = "host-config";
+
+  unpackPhase=''true'';
+
+  nativeBuildInputs = [ glibc jo coreutils gnused ];
+
+  buildPhase = ''
+   jo OS=linux \
+      ARCH=$(uname -m | sed 's/aarch64/arm64/' ) \
+      TOOLCHAIN_CONFIG=$(jo \
+        HOST_SYSTEM_HDR_DIR=${glibc.dev}/include \
+        HOST_SYSTEM_LIB_DIR=${glibc}/lib \
+        HOST_DYNAMIC_LINKER=$(ls ${glibc}/lib/ld-linux-*.so*) \
+      ) > host-config.json
+  '';
+
+  installPhase = ''
+    mkdir -p $out/share
+    cp host-config.json $out/share
+  '';
+
+}