Move id derivation to separate file

src/pkgs/default.nix

@@ -15,6 +15,8 @@ let
 
     files = callPackage ./files { } // { recurseForDerivations = true; };
 
+    ids = callPackage ./ids.nix { };
+
     nixDirectory = callPackage ./nix-directory.nix { };
 
     proot = callPackage ./proot.nix { };

src/pkgs/files/default.nix

@@ -1,7 +1,9 @@
 # Licensed under GNU Lesser General Public License v3 or later, see COPYING.
 # Copyright (c) 2019 Alexander Sosedkin and other contributors, see AUTHORS.
 
-{ buildPkgs, initialBuild, nixDirectory, nixOnDroidChannelURL, nixpkgsChannelURL }:
+{ buildPkgs, initialBuild, nixDirectory
+, nixOnDroidChannelURL, nixpkgsChannelURL
+, ids }:
 
 let
   instDir = "/data/data/com.termux.nix/files/usr";
@@ -20,14 +22,13 @@ let
 
   callPackage = buildPkgs.lib.callPackageWith (buildPkgs // {
     inherit initialBuild instDir packageInfo writeTextDir;
-    inherit groupName userName;
+    inherit groupName userName ids;
     inherit shell;
     inherit nixOnDroidChannelURL nixpkgsChannelURL;
   });
 in
 
 {
-
   etc-group = callPackage ./etc-group.nix { };
 
   etc-passwd = callPackage ./etc-passwd.nix { };

src/pkgs/files/etc-group.nix

@@ -1,20 +1,9 @@
 # Licensed under GNU Lesser General Public License v3 or later, see COPYING.
 # Copyright (c) 2019 Alexander Sosedkin and other contributors, see AUTHORS.
 
-{ coreutils, runCommand, writeTextDir, instDir, userName, groupName }:
+{ writeTextDir, userName, groupName, ids }:
-
-let
-  ids = runCommand "ids" {} ''
-    mkdir $out
-    echo -n $(${coreutils}/bin/id -u) > $out/uid
-    echo -n $(${coreutils}/bin/id -g) > $out/gid
-  '';
-  gid = builtins.readFile "${ids}/gid";
-
-in
 
 writeTextDir "etc/group" ''
   root:x:0:
-  ${groupName}:x:${gid}:${userName}
+  ${groupName}:x:${(import ids).gid}:${userName}
 ''
-

src/pkgs/files/etc-passwd.nix

@@ -1,19 +1,13 @@
 # Licensed under GNU Lesser General Public License v3 or later, see COPYING.
 # Copyright (c) 2019 Alexander Sosedkin and other contributors, see AUTHORS.
 
-{ coreutils, runCommand, writeTextDir, instDir, userName, shell }:
+{ writeTextDir, instDir, userName, shell, ids }:
 
 let
-  ids = runCommand "ids" {} ''
+  idSet = import ids;
-    mkdir $out
-    echo -n $(${coreutils}/bin/id -u) > $out/uid
-    echo -n $(${coreutils}/bin/id -g) > $out/gid
-  '';
-  uid = builtins.readFile "${ids}/uid";
-  gid = builtins.readFile "${ids}/gid";
 in
 
 writeTextDir "etc/passwd" ''
   root:x:0:0:System administrator:${instDir}/root:/bin/sh
-  ${userName}:x:${uid}:${gid}:/data/data/com.termux.nix/files/home:${shell}
+  ${userName}:x:${idSet.uid}:${idSet.gid}:/data/data/com.termux.nix/files/home:${shell}
 ''

src/pkgs/ids.nix

@@ -0,0 +1,13 @@
+# Licensed under GNU Lesser General Public License v3 or later, see COPYING.
+# Copyright (c) 2019 Alexander Sosedkin and other contributors, see AUTHORS.
+
+{ buildPkgs }:
+
+buildPkgs.runCommand "ids.nix" {} ''
+  cat > $out <<EOF
+  {
+    gid = "$(${buildPkgs.coreutils}/bin/id -g)";
+    uid = "$(${buildPkgs.coreutils}/bin/id -u)";
+  }
+  EOF
+''