virtualbox service: add support for vboxsf guest filesystem

Closes #9358

Signed-off-by: Jaka Hudoklin <jakahudoklin@gmail.com>
Fix reference to bin/mount.vboxsf.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>

nixos/modules/module-list.nix

@@ -472,6 +472,7 @@
   ./tasks/filesystems/ntfs.nix
   ./tasks/filesystems/reiserfs.nix
   ./tasks/filesystems/unionfs-fuse.nix
+  ./tasks/filesystems/vboxsf.nix
   ./tasks/filesystems/vfat.nix
   ./tasks/filesystems/xfs.nix
   ./tasks/filesystems/zfs.nix

nixos/modules/tasks/filesystems/vboxsf.nix

@@ -0,0 +1,23 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  inInitrd = any (fs: fs == "vboxsf") config.boot.initrd.supportedFilesystems;
+
+  package = pkgs.runCommand "mount.vboxsf" {} ''
+    mkdir -p $out/bin
+    cp ${pkgs.linuxPackages.virtualboxGuestAdditions}/bin/mount.vboxsf $out/bin
+  '';
+in
+
+{
+  config = mkIf (any (fs: fs == "vboxsf") config.boot.supportedFilesystems) {
+
+    system.fsPackages = [ package ];
+
+    boot.initrd.kernelModules = mkIf inInitrd [ "vboxsf" ];
+
+  };
+}

nixos/modules/virtualisation/virtualbox-guest.nix

@@ -32,7 +32,8 @@ in
 
     boot.extraModulePackages = [ kernel.virtualboxGuestAdditions ];
 
-    boot.kernelModules = [ "vboxsf" ];
+    boot.supportedFilesystems = [ "vboxsf" ];
+    boot.initrd.supportedFilesystems = [ "vboxsf" ];
 
     users.extraGroups.vboxsf.gid = config.ids.gids.vboxsf;