Prevent unload of modules which implement an Optional API.

Once an Optional API module is loaded it should stay loaded.  Unloading
an optional API module runs the risk of a crash if something else is
using it.  This patch causes all optional API providers to tell the
module loader not to unload except at shutdown.

ASTERISK-27389

Change-Id: Ia07786fe655681aec49cc8d3d96e06483b11f5e6

res/res_agi.c

@@ -4715,6 +4715,10 @@ static int load_module(void)
 		unload_module();
 		return AST_MODULE_LOAD_DECLINE;
 	}
+
+	/* For Optional API. */
+	ast_module_shutdown_ref(ast_module_info->self);
+
 	return AST_MODULE_LOAD_SUCCESS;
 }
 

res/res_http_websocket.c

@@ -1439,6 +1439,9 @@ static int load_module(void)
 	ast_http_uri_link(&websocketuri);
 	websocket_add_protocol_internal("echo", websocket_echo_callback);
 
+	/* For Optional API. */
+	ast_module_shutdown_ref(ast_module_info->self);
+
 	return 0;
 }
 

res/res_monitor.c

@@ -987,6 +987,9 @@ static int load_module(void)
 	ast_manager_register_xml("PauseMonitor", EVENT_FLAG_CALL, pause_monitor_action);
 	ast_manager_register_xml("UnpauseMonitor", EVENT_FLAG_CALL, unpause_monitor_action);
 
+	/* For Optional API. */
+	ast_module_shutdown_ref(ast_module_info->self);
+
 	return AST_MODULE_LOAD_SUCCESS;
 }
 

res/res_pktccops.c

@@ -1474,6 +1474,10 @@ static int load_module(void)
 	}
 	ast_cli_register_multiple(cli_pktccops, sizeof(cli_pktccops) / sizeof(struct ast_cli_entry));
 	restart_pktc_thread();
+
+	/* For Optional API. */
+	ast_module_shutdown_ref(ast_module_info->self);
+
 	return 0;
 }
 

res/res_smdi.c

@@ -1407,6 +1407,10 @@ static int _unload_module(int fromload)
 	}
 
 	smdi_loaded = 0;
+
+	/* For Optional API. */
+	ast_module_shutdown_ref(ast_module_info->self);
+
 	return 0;
 }
 

res/res_statsd.c

@@ -355,6 +355,9 @@ static int load_module(void)
 		return AST_MODULE_LOAD_DECLINE;
 	}
 
+	/* For Optional API. */
+	ast_module_shutdown_ref(ast_module_info->self);
+
 	return AST_MODULE_LOAD_SUCCESS;
 }