libvirt: fix virt-secret-init-encryption (#496839)

nixos/modules/virtualisation/libvirtd.nix

@@ -530,7 +530,10 @@ in
           "nix-helpers"
           "nix-ovmf"
         ];
-        StateDirectory = subDirs [ "dnsmasq" ];
+        StateDirectory = subDirs [
+          "dnsmasq"
+          "secrets"
+        ];
       };
     };
 

pkgs/by-name/li/libvirt/package.nix

@@ -33,11 +33,13 @@
   python3,
   readline,
   rpcsvc-proto,
+  runtimeShell,
   stdenv,
   replaceVars,
   xhtml1,
   json_c,
   writeScript,
+  writeShellApplication,
   nixosTests,
 
   # Linux
@@ -180,7 +182,23 @@ stdenv.mkDerivation rec {
     sed -i '/libxlxml2domconfigtest/d' tests/meson.build
     substituteInPlace src/libxl/libxl_capabilities.h \
      --replace-fail /usr/lib/xen ${xen}/libexec/xen
-  '';
+  ''
+  + lib.optionalString isLinux (
+    let
+      script = writeShellApplication {
+        name = "virt-secret-init-encryption-sh";
+        runtimeInputs = [
+          coreutils
+          systemd
+        ];
+        text = ''exec ${runtimeShell} "$@"'';
+      };
+    in
+    ''
+      substituteInPlace src/secret/virt-secret-init-encryption.service.in \
+        --replace-fail /usr/bin/sh ${lib.getExe script}
+    ''
+  );
 
   strictDeps = true;