systemd: add sysupdated (#424101)

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

@@ -11,7 +11,14 @@ let
 
   format = pkgs.formats.ini { listToValue = toString; };
 
-  definitionsDirectory = utils.systemdUtils.lib.definitions "sysupdate.d" format cfg.transfers;
+  # TODO: Switch back to using utils.systemdUtils.lib.definitions once
+  # https://github.com/systemd/systemd/pull/38187 is resolved. Also ensure
+  # utils.systemdUtils.lib.definitions is capable of setting a custom file
+  # suffix.
+  sysupdateTransfers = lib.mapAttrs' (name: value: {
+    name = "sysupdate.d/${name}.transfer";
+    value.source = format.generate "${name}.transfer" value;
+  }) cfg.transfers;
 in
 {
   options.systemd.sysupdate = {
@@ -114,14 +121,23 @@ in
   };
 
   config = lib.mkIf cfg.enable {
+    assertions = [
+      {
+        assertion = config.systemd.package.withSysupdate;
+        message = "Cannot enable systemd-sysupdate with systemd package not built with sysupdate support";
+      }
+    ];
 
     systemd.additionalUpstreamSystemUnits = [
       "systemd-sysupdate.service"
       "systemd-sysupdate.timer"
       "systemd-sysupdate-reboot.service"
       "systemd-sysupdate-reboot.timer"
+      "systemd-sysupdated.service"
     ];
 
+    systemd.services.systemd-sysupdated.aliases = [ "dbus-org.freedesktop.sysupdate1.service" ];
+
     systemd.timers = {
       "systemd-sysupdate" = {
         wantedBy = [ "timers.target" ];
@@ -133,8 +149,11 @@ in
       };
     };
 
-    environment.etc."sysupdate.d".source = definitionsDirectory;
+    environment.etc = sysupdateTransfers;
   };
 
-  meta.maintainers = with lib.maintainers; [ nikstur ];
+  meta.maintainers = with lib.maintainers; [
+    nikstur
+    jmbaur
+  ];
 }

nixos/tests/systemd-sysupdate.nix

@@ -1,7 +1,7 @@
 # Tests downloading a signed update artifact from a server to a target machine.
 # This test does not rely on the `systemd.timer` units provided by the
-# `systemd-sysupdate` module but triggers the `systemd-sysupdate` service
-# manually to make the test more robust.
+# `systemd-sysupdate` module but triggers the `updatectl` tool directly to
+# demonstrate how to initiate updates manually.
 
 { lib, pkgs, ... }:
 
@@ -62,7 +62,8 @@ in
   testScript = ''
     server.wait_for_unit("nginx.service")
 
-    target.succeed("systemctl start systemd-sysupdate")
+    print(target.succeed("updatectl list"))
+    target.succeed("updatectl update")
     assert "nixos" in target.wait_until_succeeds("cat /nixos_1.txt", timeout=5)
   '';
 }

pkgs/os-specific/linux/systemd/default.nix

@@ -559,6 +559,7 @@ stdenv.mkDerivation (finalAttrs: {
       (lib.mesonEnable "libiptc" withIptables)
       (lib.mesonEnable "repart" withRepart)
       (lib.mesonEnable "sysupdate" withSysupdate)
+      (lib.mesonEnable "sysupdated" withSysupdate)
       (lib.mesonEnable "seccomp" withLibseccomp)
       (lib.mesonEnable "selinux" withSelinux)
       (lib.mesonEnable "tpm2" withTpm2Tss)
@@ -905,6 +906,7 @@ stdenv.mkDerivation (finalAttrs: {
       withMachined
       withNetworkd
       withPortabled
+      withSysupdate
       withTimedated
       withTpm2Tss
       withUtmp