Ensure standby.signal is set correctly if -D/--data-directory supplied

When cloning a standby, it's possible to do a "raw" clone by providing
-D/--data-directory but no repmgr.conf file. However the code which
creates "standby.signal" was assuming the presence of a valid
repmgr.conf complete with "data_directory" configuration.

This is very much a niche-use case.

repmgr-action-node.c

@@ -2813,7 +2813,8 @@ do_node_rejoin(void)
 				log_notice(_("temporarily removing \"standby.signal\""));
 				log_detail(_("this is required so pg_rewind can fix the unclean shutdown"));
 
-				make_standby_signal_path(standby_signal_file_path);
+				make_standby_signal_path(config_file_options.data_directory,
+										 standby_signal_file_path);
 
 				if (unlink(standby_signal_file_path) < 0 && errno != ENOENT)
 				{
@@ -2838,7 +2839,7 @@ do_node_rejoin(void)
 				 * of whether the pg_rewind operation failed.
 				 */
 				log_notice(_("recreating \"standby.signal\""));
-				write_standby_signal();
+				write_standby_signal(config_file_options.data_directory);
 			}
 
 			if (ret == false)

repmgr-action-standby.c

@@ -173,21 +173,6 @@ do_standby_clone(void)
 
 	initialize_conninfo_params(&recovery_conninfo, false);
 
-	/*
-	 * --replication-conf-only provided - we'll handle that separately
-	 */
-	if (runtime_options.replication_conf_only == true)
-	{
-		return _do_create_replication_conf();
-	}
-
-	/*
-	 * conninfo params for the actual upstream node (which might be different
-	 * to the node we're cloning from) to write to recovery.conf
-	 */
-
-	mode = get_standby_clone_mode();
-
 	/*
 	 * Copy the provided data directory; if a configuration file was provided,
 	 * use the (mandatory) value from that; if -D/--pgdata was provided, use
@@ -215,6 +200,20 @@ do_standby_clone(void)
 		exit(ERR_BAD_CONFIG);
 	}
 
+	/*
+	 * --replication-conf-only provided - we'll handle that separately
+	 */
+	if (runtime_options.replication_conf_only == true)
+	{
+		return _do_create_replication_conf();
+	}
+
+	/*
+	 * conninfo params for the actual upstream node (which might be different
+	 * to the node we're cloning from) to write to recovery.conf
+	 */
+
+	mode = get_standby_clone_mode();
 
 	if (mode == barman)
 	{
@@ -1479,7 +1478,7 @@ _do_create_replication_conf(void)
 		}
 		else
 		{
-			if (write_standby_signal() == false)
+			if (write_standby_signal(local_data_directory) == false)
 			{
 				log_error(_("unable to write \"standby.signal\" file"));
 			}
@@ -8001,7 +8000,7 @@ create_recovery_file(t_node_info *node_record, t_conninfo_param_list *primary_co
 			return false;
 		}
 
-		if (write_standby_signal() == false)
+		if (write_standby_signal(local_data_directory) == false)
 		{
 			return false;
 		}

repmgr-client-global.h

@@ -282,8 +282,8 @@ extern void get_node_config_directory(char *config_dir_buf);
 extern void get_node_data_directory(char *data_dir_buf);
 extern void init_node_record(t_node_info *node_record);
 extern bool can_use_pg_rewind(PGconn *conn, const char *data_directory, PQExpBufferData *reason);
-extern void make_standby_signal_path(char *buf);
+extern void make_standby_signal_path(const char *data_dir, char *buf);
-extern bool write_standby_signal(void);
+extern bool write_standby_signal(const char *data_dir);
 
 extern bool create_replication_slot(PGconn *conn, char *slot_name, t_node_info *upstream_node_record, PQExpBufferData *error_msg);
 extern bool drop_replication_slot_if_exists(PGconn *conn, int node_id, char *slot_name);

repmgr-client.c

@@ -3661,11 +3661,11 @@ can_use_pg_rewind(PGconn *conn, const char *data_directory, PQExpBufferData *rea
 
 
 void
-make_standby_signal_path(char *buf)
+make_standby_signal_path(const char *data_dir, char *buf)
 {
 	snprintf(buf, MAXPGPATH,
 			 "%s/%s",
-			 config_file_options.data_directory,
+			 data_dir,
 			 STANDBY_SIGNAL_FILE);
 }
 
@@ -3673,13 +3673,15 @@ make_standby_signal_path(char *buf)
  * create standby.signal (PostgreSQL 12 and later)
  */
 bool
-write_standby_signal(void)
+write_standby_signal(const char *data_dir)
 {
 	char	    standby_signal_file_path[MAXPGPATH] = "";
 	FILE	   *file;
 	mode_t		um;
 
-	make_standby_signal_path(standby_signal_file_path);
+	Assert(data_dir != NULL);
+
+	make_standby_signal_path(data_dir, standby_signal_file_path);
 
 	/* Set umask to 0600 */
 	um = umask((~(S_IRUSR | S_IWUSR)) & (S_IRWXG | S_IRWXO));