+/**
+ * Parse `run_as_user` and `run_as_group` and remember the results in internal fields.
+ * This is called automatically by daemon_init(), but also provided as a separate
+ * function in case you want to use daemon_switch_ugid(). Upon parse error, it calls die().
+ **/
+void daemon_resolve_ugid(struct daemon_params *dp);
+
+/**
+ * Switch user and group as specified by the `run_as_user` and `run_as_group`.
+ * This is performed automatically by daemon_run(), but sometimes you might want to
+ * switch the user and group separately. In this case, you have to call daemon_resolve_ugid()
+ * beforehand.
+ **/
+void daemon_switch_ugid(struct daemon_params *dp);
+
+#define DAEMON_ERR_LEN 256
+
+/** Parameters passed to @daemon_control() **/
+struct daemon_control_params {
+ const char *pid_file; // A path to PID file
+ const char *guard_file; // A path to guard file
+ int action; // Action to perform (DAEMON_CONTROL_xxx)
+ char * const *argv; // Daemon's arguments, NULL-terminated (for DAEMON_CONTROL_START)
+ int signal; // Signal to send (for DAEMON_CONTROL_SIGNAL)
+ char error_msg[DAEMON_ERR_LEN]; // A detailed error message returned (for DAEMON_STATUS_ERROR)
+};
+
+enum daemon_control_action {
+ DAEMON_CONTROL_CHECK = 1,
+ DAEMON_CONTROL_START,
+ DAEMON_CONTROL_STOP,
+ DAEMON_CONTROL_SIGNAL,
+};
+
+/**
+ * Perform an action on a daemon:
+ *
+ * * `DAEMON_CONTROL_START` to start the daemon
+ * * `DAEMON_CONTROL_STOP` to stop the daemon (send `SIGTERM` or `dc->signal` if non-zero)
+ * * `DAEMON_CONTROL_CHECK` to check that the daemon is running
+ * * `DAEMON_CONTROL_SIGNAL` to send a signal to the daemon (send `SIGHUP` or `dc->signal` if non-zero)
+ *
+ * The function returns a status code:
+ *
+ * * `DAEMON_STATUS_OK` if the action has been performed successfully
+ * * `DAEMON_STATUS_ALREADY_DONE` if the daemon is already in the requested state
+ * * `DAEMON_STATUS_NOT_RUNNING` if the action failed, because the daemon is not running
+ * * `DAEMON_STATUS_ERROR` if the action failed for some other reason (in this case,
+ * `dc->error_msg` contains a full error message)
+ * * `DAEMON_STATUS_STALE` if the daemon was in an undefined state (e.g., a stale PID file);
+ * for `DAEMON_CONTROL_START`, it means success
+ **/
+enum daemon_control_status daemon_control(struct daemon_control_params *dc);
+
+// XXX: Also used as exit codes of the ucw-daemon-control utility.
+enum daemon_control_status {
+ DAEMON_STATUS_OK = 0,
+ DAEMON_STATUS_ALREADY_DONE = 100,
+ DAEMON_STATUS_NOT_RUNNING = 101,
+ DAEMON_STATUS_ERROR = 102,
+ DAEMON_STATUS_STALE = 103,
+};
+