Merge pull request #168774 from helsinki-systems/feat/systemd-shutdown

nixos/systemd: Properly shut down the system

nixos/modules/system/boot/systemd/shutdown.nix

@@ -0,0 +1,32 @@
+{ config, lib, ... }: let
+
+  cfg = config.boot.systemd.shutdown;
+
+in {
+  options.boot.systemd.shutdown = {
+    enable = lib.mkEnableOption "pivoting back to an initramfs for shutdown" // { default = true; };
+  };
+
+  config = lib.mkIf cfg.enable {
+    systemd.services.generate-shutdown-ramfs = {
+      description = "Generate shutdown ramfs";
+      before = [ "shutdown.target" ];
+      unitConfig = {
+        DefaultDependencies = false;
+        ConditionFileIsExecutable = [
+          "!/run/initramfs/shutdown"
+          "/run/current-system/systemd/lib/systemd/systemd-shutdown"
+        ];
+      };
+
+      serviceConfig.Type = "oneshot";
+      script = ''
+        mkdir -p /run/initramfs
+        if ! mountpoint -q /run/initramfs; then
+          mount -t tmpfs tmpfs /run/initramfs
+        fi
+        cp /run/current-system/systemd/lib/systemd/systemd-shutdown /run/initramfs/shutdown
+      '';
+    };
+  };
+}