MT#61856 call_flags: return actual error

In the list of functions return actual err string.
And pass it up to the flags parser, which will return
the actual error if given.

This also will be used by call-backs.

Change-Id: I0d65508afb35763bb0673219d711df22f874b98f

daemon/call_flags.c

@@ -137,7 +137,7 @@ static const char *call_ng_flags_str_pair_ht(str *s, unsigned int idx, helper_ar
 	if (!str_token(&token, s_copy, '>')) {
 		ilog(LOG_WARN, "SDP manipulations: Ignoring invalid token '" STR_FORMAT "'", STR_FMT(s));
 		free(s_copy);
-		return NULL; // return error?
+		return "invalid token given";
 	}
 	str_case_value_ht *ht = arg.svt;
 	if (!t_hash_table_is_set(*ht))
@@ -202,6 +202,7 @@ static const char *ng_sdp_attr_media_iter(const ng_parser_t *parser, str *comman
 
 		default:
 			ilog(LOG_WARN, "SDP manipulations: Unknown SDP manipulation command type.");
+			return "unknown manipulation command";
 	}
 
 	return NULL;
@@ -213,12 +214,12 @@ static const char *ng_sdp_attr_manipulations_iter(const ng_parser_t *parser, str
 	if (!sm) {
 		ilog(LOG_WARN, "SDP manipulations: unsupported SDP section '" STR_FORMAT "' targeted.",
 				STR_FMT(media_type));
-		return NULL;
+		return "unsupported sdp section";
 	}
 
 	if (!parser->is_dict(command_action)) {
 		ilog(LOG_WARN, "SDP manipulations: Wrong content for SDP section.");
-		return NULL;
+		return "wrong content given";
 	}
 
 	return parser->dict_iter(parser, command_action, ng_sdp_attr_media_iter, sm);
@@ -226,7 +227,7 @@ static const char *ng_sdp_attr_manipulations_iter(const ng_parser_t *parser, str
 INLINE const char *ng_sdp_attr_manipulations(const ng_parser_t *parser, sdp_ng_flags *flags, parser_arg value) {
 	if (!parser->is_dict(value)) {
 		ilog(LOG_WARN, "SDP manipulations: Wrong type for this type of command.");
-		return NULL;
+		return "wrong type used";
 	}
 	return parser->dict_iter(parser, value, ng_sdp_attr_manipulations_iter, flags);
 }
@@ -242,17 +243,17 @@ static const char *ng_sdp_media_remove_iter(str *media_type, unsigned int i, hel
 		ilog(LOG_WARN, "SDP manipulations: unsupported SDP section '" STR_FORMAT "' targeted.",
 				STR_FMT(media_type));
 		/* only known media types are supported */
-		return NULL; // return error?
+		return "unsupported sdp section";
 	}
 	arg.flags->sdp_media_remove[id] = true;
 	return NULL;
 }
-INLINE void ng_sdp_media_remove(const ng_parser_t *parser, sdp_ng_flags *flags, parser_arg value) {
+INLINE const char *ng_sdp_media_remove(const ng_parser_t *parser, sdp_ng_flags *flags, parser_arg value) {
 	if (!parser->is_list(value)) {
 		ilog(LOG_WARN, "SDP media remove: Wrong type for this type of command.");
-		return;
+		return "wrong type used";
 	}
-	parser->list_iter(parser, value, ng_sdp_media_remove_iter, NULL, flags);
+	return parser->list_iter(parser, value, ng_sdp_media_remove_iter, NULL, flags);
 }
 
 static const char *ng_el_option(str *s, unsigned int idx, helper_arg arg) {
@@ -1920,7 +1921,7 @@ const char *call_ng_main_flags(const ng_parser_t *parser, str *key, parser_arg v
 		case CSH_LOOKUP("SDP-attr"):
 		case CSH_LOOKUP("sdp attr"):
 		case CSH_LOOKUP("SDP attr"):
-			ng_sdp_attr_manipulations(parser, out, value);
+			return ng_sdp_attr_manipulations(parser, out, value);
 			break;
 		case CSH_LOOKUP("sdp-media-remove"):
 		case CSH_LOOKUP("SDP-media-remove"):
@@ -1928,7 +1929,7 @@ const char *call_ng_main_flags(const ng_parser_t *parser, str *key, parser_arg v
 		case CSH_LOOKUP("SDP_media_remove"):
 		case CSH_LOOKUP("sdp media remove"):
 		case CSH_LOOKUP("SDP media remove"):
-			ng_sdp_media_remove(parser, out, value);
+			return ng_sdp_media_remove(parser, out, value);
 			break;
 		case CSH_LOOKUP("set-label"):
 		case CSH_LOOKUP("set label"):