Fix Coverity Scan #1619416

apps/mosquitto_ctrl/ctrl_shell_dynsec.c

@@ -620,6 +620,11 @@ static void line_callback(char *line)
 	char *saveptr = NULL;
 	char *command = strtok_r(line, " ", &saveptr);
 
+	if(!command){
+		free(line);
+		return;
+	}
+
 	if(!strcasecmp(command, "addClientRole")){
 		ctrl_shell_command_generic_arg2("addClientRole", "username", "rolename", &saveptr);
 	}else if(!strcasecmp(command, "addGroupClient")){

apps/mosquitto_ctrl/ctrl_shell_post_connect.c

@@ -97,8 +97,13 @@ static void line_callback(char *line)
 	}
 
 	char *saveptr = NULL;
-	char *command = strtok_r(line, " ", &saveptr);
 	bool found = false;
+	char *command = strtok_r(line, " ", &saveptr);
+
+	if(!command){
+		free(line);
+		return;
+	}
 
 	for(size_t i=0; i<sizeof(mod_data)/sizeof(struct module_data); i++){
 		if(!strcasecmp(command, mod_data[i].name)){

apps/mosquitto_ctrl/ctrl_shell_pre_connect.c

@@ -104,6 +104,10 @@ static void line_callback(char *line)
 	}
 
 	command = strtok_r(line, " ", &saveptr);
+	if(!command){
+		free(line);
+		return;
+	}
 
 	if(!strcasecmp(command, "auth")){
 		free(data.username);