Log unhandled IRC errors as LOG_INFO in bip.log

This will allow for user feedback in main bip.log when an IRC error
occurs, like:
- 401 ERR_NOSUCHNICK
- 404 ERR_CANNOTSENDTOCHAN
- 432 ERR_ERRONEUSNICKNAME

These should not be logged as LOG_ERROR as they are not bip errors but
usually on the end user instead.

Signed-off-by: Loïc Gomez <bip@animanova.fr>

src/irc.c

@@ -33,6 +33,7 @@
 extern int sighup;
 extern bip_t *_bip;
 
+static int irc_generic_error(struct link_server *server, struct line *line);
 static int irc_join(struct link_server *server, struct line *line);
 static int irc_part(struct link_server *server, struct line *line);
 static int irc_mode(struct link_server *server, struct line *line);
@@ -625,6 +626,10 @@ int irc_dispatch_server(bip_t *bip, struct link_server *server,
 		ret = irc_quit(server, line);
 	} else if (irc_line_elem_equals(line, 0, "NICK")) {
 		ret = irc_nick(server, line);
+	} else if (irc_line_is_error(line)) {
+		// IRC errors catchall (for unhandled ones)
+		// logs error to bip.log
+		ret = irc_generic_error(server, line);
 	}
 
 	if (ret == OK_COPY) {
@@ -1448,6 +1453,17 @@ static int origin_is_me(struct line *l, struct link_server *server)
 	return 0;
 }
 
+static int irc_generic_error(struct link_server *server, struct line *line)
+{
+	if (irc_line_count(line) == 4)
+		mylog(LOG_INFO, "[%s] IRC error: %s", LINK(server)->name,
+			irc_line_elem(line, 3));
+	else
+		mylog(LOG_INFO, "[%s] IRC error: %s", LINK(server)->name,
+			irc_line_to_string(line));
+	return OK_COPY;
+}
+
 static int irc_join(struct link_server *server, struct line *line)
 {
 	char *s_nick;

src/line.c

@@ -143,6 +143,13 @@ void irc_line_drop(struct line *line, int elem)
 	bip_cfree(array_drop(&line->words, elem));
 }
 
+unsigned int irc_line_is_error(struct line *line)
+{
+	const char *irc_code = irc_line_elem(line, 0);
+	const char *error_code = "4";
+	return (irc_code[0] == error_code[0]);
+}
+
 int irc_line_elem_equals(struct line *line, int elem, const char *cmp)
 {
 	return !strcmp(irc_line_elem(line, elem), cmp);

src/line.h

@@ -98,6 +98,7 @@ int irc_line_includes(struct line *line, int elem);
 const char *irc_line_elem(struct line *line, int elem);
 int irc_line_count(struct line *line);
 char *irc_line_pop(struct line *l);
+unsigned int irc_line_is_error(struct line *line);
 int irc_line_elem_equals(struct line *line, int elem, const char *cmp);
 int irc_line_elem_case_equals(struct line *line, int elem, const char *cmp);
 void irc_line_drop(struct line *line, int elem);