init nix-os configuraion files

modules/nixos/virtualize/libvirtd/hooks.nix

@@ -0,0 +1,37 @@
+{ pkgs, ... }:
+{
+  # Load Hooks for Libvirt
+  systemd.services.libvirtd.preStart = let
+    qemuHook = pkgs.writeScript "qemu-hook" ''
+      #!${pkgs.stdenv.shell}
+
+      GUEST_NAME="$1"
+      HOOK_NAME="$2"
+      STATE_NAME="$3"
+      MISC="$\{@:4}"
+
+      BASEDIR="$(dirname $0)"
+
+      HOOKPATH="$BASEDIR/qemu.d/$GUEST_NAME/$HOOK_NAME/$STATE_NAME"
+      set -e # If a script exits with an error, we should as well.
+
+      if [ -f "$HOOKPATH" ]; then
+      eval \""$HOOKPATH"\" "$@"
+      elif [ -d "$HOOKPATH" ]; then
+      while read file; do
+        eval \""$file"\" "$@"
+      done <<< "$(find -L "$HOOKPATH" -maxdepth 1 -type f -executable -print;)"
+      fi
+    '';
+  in ''
+    mkdir -p /var/lib/libvirt/hooks
+    chmod 755 /var/lib/libvirt/hooks
+
+    # Copy hook files
+    ln -sf ${qemuHook} /var/lib/libvirt/hooks/qemu
+    cp -rfT ${./qemu.d} /var/lib/libvirt/hooks/qemu.d
+
+    # Make executable
+    chmod -R +x /var/lib/libvirt/hooks/qemu.d/
+  '';
+}