-/* Get systemd unit (i.e. service) name from PID. This will return an
- * error for non-service processes. */
-int sd_pid_get_unit(pid_t, char **unit);
+/* Get systemd unit (i.e. service) name from PID, for system
+ * services. This will return an error for non-service processes. */
+int sd_pid_get_unit(pid_t pid, char **unit);
+
+/* Get systemd unit (i.e. service) name from PID, for user
+ * services. This will return an error for non-user-service
+ * processes. */
+int sd_pid_get_user_unit(pid_t pid, char **unit);
+
+/* Get machine name from PID, for processes assigned to VM or
+ * container. This will return an error for non-machine processes. */
+int sd_pid_get_machine_name(pid_t pid, char **name);