Merge pull request #64 from K900/main

binfmt / interop fixes

Author: nzbr

modules/wsl-distro.nix

@@ -28,6 +28,20 @@ with builtins; with lib;
         type = attrsOf (attrsOf coercedToStr);
         description = "Entries that are added to /etc/wsl.conf";
       };
+
+      interop = {
+        register = mkOption {
+          type = bool;
+          default = true;
+          description = "Explicitly register the binfmt_misc handler for Windows executables";
+        };
+
+        includePath = mkOption {
+          type = bool;
+          default = true;
+          description = "Include Windows PATH in WSL PATH";
+        };
+      };
     };
 
   config =
@@ -47,12 +61,22 @@ with builtins; with lib;
       };
 
       # WSL is closer to a container than anything else
-      boot.isContainer = true;
+      boot = {
+        isContainer = true;
+
+        binfmt.registrations = mkIf cfg.interop.register {
+          WSLInterop = {
+            magicOrExtension = "MZ";
+            interpreter = "/init";
+            fixBinary = true;
+          };
+        };
+      };
       environment.noXlibs = lib.mkForce false; # override xlibs not being installed (due to isContainer) to enable the use of GUI apps
 
       environment = {
         # Include Windows %PATH% in Linux $PATH.
-        extraInit = ''PATH="$PATH:$WSLPATH"'';
+        extraInit = mkIf cfg.interop.includePath ''PATH="$PATH:$WSLPATH"'';
 
         etc = {
           "wsl.conf".text = generators.toINI { } cfg.wslConf;

syschdemd.nix

@@ -12,4 +12,9 @@ pkgs.substituteAll {
   inherit defaultUser;
   inherit (config.security) wrapperDir;
   fsPackagesPath = lib.makeBinPath config.system.fsPackages;
+
+  systemdWrapper = pkgs.writeShellScript "systemd-wrapper.sh" ''
+    mount -t binfmt_misc binfmt_misc /proc/sys/fs/binfmt_misc
+    exec systemd
+  '';
 }

syschdemd.sh

@@ -16,9 +16,11 @@ if [ ! -e "/run/current-system" ]; then
 fi
 
 if [ ! -e "/run/systemd.pid" ]; then
+    @wrapperDir@/umount /proc/sys/fs/binfmt_misc
+
     PATH=/run/current-system/systemd/lib/systemd:@fsPackagesPath@ \
         LOCALE_ARCHIVE=/run/current-system/sw/lib/locale/locale-archive \
-        @daemonize@/bin/daemonize /run/current-system/sw/bin/unshare -fp --mount-proc systemd
+        @daemonize@/bin/daemonize /run/current-system/sw/bin/unshare -fp --mount-proc @systemdWrapper@
     /run/current-system/sw/bin/pgrep -xf systemd >/run/systemd.pid
 
     # Wait for systemd to start