--- /dev/null
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "varlink-io.systemd.h"
+
+/* These are local errors that never cross the wire, and are our own invention */
+static VARLINK_DEFINE_ERROR(Disconnected);
+static VARLINK_DEFINE_ERROR(TimedOut);
+static VARLINK_DEFINE_ERROR(Protocol);
+
+/* This one we invented, and use for generically propagating system errors (errno) to clients */
+static VARLINK_DEFINE_ERROR(
+ System,
+ VARLINK_DEFINE_FIELD(errno, VARLINK_INT, 0));
+
+VARLINK_DEFINE_INTERFACE(
+ io_systemd,
+ "io.systemd",
+ &vl_error_Disconnected,
+ &vl_error_TimedOut,
+ &vl_error_Protocol,
+ &vl_error_System);
--- /dev/null
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "varlink-org.varlink.service.h"
+
+static VARLINK_DEFINE_METHOD(
+ GetInfo,
+ VARLINK_DEFINE_OUTPUT(vendor, VARLINK_STRING, 0),
+ VARLINK_DEFINE_OUTPUT(product, VARLINK_STRING, 0),
+ VARLINK_DEFINE_OUTPUT(version, VARLINK_STRING, 0),
+ VARLINK_DEFINE_OUTPUT(url, VARLINK_STRING, 0),
+ VARLINK_DEFINE_OUTPUT(interfaces, VARLINK_STRING, VARLINK_ARRAY));
+
+static VARLINK_DEFINE_METHOD(
+ GetInterfaceDescription,
+ VARLINK_DEFINE_OUTPUT(interface, VARLINK_STRING, 0));
+
+static VARLINK_DEFINE_ERROR(
+ InterfaceNotFound,
+ VARLINK_DEFINE_FIELD(interface, VARLINK_STRING, 0));
+
+static VARLINK_DEFINE_ERROR(
+ MethodNotFound,
+ VARLINK_DEFINE_FIELD(method, VARLINK_STRING, 0));
+
+static VARLINK_DEFINE_ERROR(
+ MethodNotImplemented,
+ VARLINK_DEFINE_FIELD(method, VARLINK_STRING, 0));
+
+static VARLINK_DEFINE_ERROR(
+ InvalidParameter,
+ VARLINK_DEFINE_FIELD(parameter, VARLINK_STRING, 0));
+
+static VARLINK_DEFINE_ERROR(PermissionDenied);
+
+/* As per https://varlink.org/Service */
+VARLINK_DEFINE_INTERFACE(
+ org_varlink_service,
+ "org.varlink.service",
+ &vl_method_GetInfo,
+ &vl_method_GetInterfaceDescription,
+ &vl_error_InterfaceNotFound,
+ &vl_error_MethodNotFound,
+ &vl_error_MethodNotImplemented,
+ &vl_error_InvalidParameter,
+ &vl_error_PermissionDenied);