nixos/envfs: add extraFallbackPathCommands options

this is mainly useful for restricted platforms like wsl which require
some extra entries in /bin/

1 files changed, 11 insertions, 3 deletions

diff --git a/nixos/modules/tasks/filesystems/envfs.nix b/nixos/modules/tasks/filesystems/envfs.nix
index df4ce12407bd9..76344f5f87eaf 100644
--- a/nixos/modules/tasks/filesystems/envfs.nix
+++ b/nixos/modules/tasks/filesystems/envfs.nix
@@ -7,11 +7,11 @@ let
       device = "none";
       fsType = "envfs";
       options = [
-        "fallback-path=${pkgs.runCommand "fallback-path" {} ''
+        "fallback-path=${pkgs.runCommand "fallback-path" {} (''
           mkdir -p $out
           ln -s ${config.environment.usrbinenv} $out/env
           ln -s ${config.environment.binsh} $out/sh
-        ''}"
+        '' + cfg.extraFallbackPathCommands)}"
       ];
     };
     "/bin" = {
@@ -31,11 +31,19 @@ in {
           etc.
         '';
       };
+
       package = lib.mkOption {
         type = lib.types.package;
-        description = lib.mdDoc "Which package to use for the envfs.";
         default = pkgs.envfs;
         defaultText = lib.literalExpression "pkgs.envfs";
+        description = lib.mdDoc "Which package to use for the envfs.";
+      };
+
+      extraFallbackPathCommands = lib.mkOption {
+        type = lib.types.lines;
+        default = "";
+        example = "ln -s $''{pkgs.bash}/bin/bash $out/bash";
+        description = lib.mdDoc "Extra commands to run in the package that contains fallback executables in case not other executable is found";
       };
     };
   };