m_alias: Preserve protocol framing characters

include/msgbuf.h

@@ -38,6 +38,7 @@ struct MsgBuf {
 	const char *origin;		/* the origin of the message (or NULL) */
 	const char *target;		/* the target of the message (either NULL, or custom defined) */
 	const char *cmd;		/* the cmd/verb of the message (either NULL, or para[0]) */
+	char *endp;			/* one past the end of the original array */
 
 	size_t n_para;			/* the number of parameters (always at least 1 if a full message) */
 	const char *para[MAXPARA];	/* parameters vector (starting with cmd as para[0]) */
@@ -76,6 +77,12 @@ struct MsgBuf_cache {
  */
 int msgbuf_parse(struct MsgBuf *msgbuf, char *line);
 
+/*
+ * Unparse the tail of a msgbuf perfectly, preserving framing details
+ * msgbuf->para[n] will reach to the end of the line
+ */
+void msgbuf_reconstruct_tail(struct MsgBuf *msgbuf, size_t n);
+
 /*
  * unparse a pure MsgBuf into a buffer.
  * if origin is NULL, me.name will be used.

ircd/msgbuf.c

@@ -154,6 +154,7 @@ msgbuf_parse(struct MsgBuf *msgbuf, char *line)
 	if (*ch == '\0')
 		return 2;
 
+	msgbuf->endp = &ch[strlen(ch)];
 	msgbuf->n_para = rb_string_to_array(ch, (char **)msgbuf->para, MAXPARA);
 	if (msgbuf->n_para == 0)
 		return 3;
@@ -162,6 +163,40 @@ msgbuf_parse(struct MsgBuf *msgbuf, char *line)
 	return 0;
 }
 
+/*
+ * Unparse the tail of a msgbuf perfectly, preserving framing details
+ * msgbuf->para[n] will reach to the end of the line
+ */
+
+void
+msgbuf_reconstruct_tail(struct MsgBuf *msgbuf, size_t n)
+{
+	if (msgbuf->endp == NULL || n > msgbuf->n_para)
+		return;
+
+	char *c;
+	const char *c_;
+
+	if (n == 0)
+		c_ = msgbuf->para[n];
+	else
+		c_ = msgbuf->para[n-1] + strlen(msgbuf->para[n-1]) + 1;
+
+	if (n == msgbuf->n_para && c_ == msgbuf->endp)
+		return;
+
+	msgbuf->para[n] = c_;
+	/* promote to non-const. msgbuf->endp witnesses that this is allowed */
+	c = msgbuf->endp - (msgbuf->endp - c_);
+
+	for ( ; c < msgbuf->endp; c++)
+	{
+		if (*c == '\0')
+			*c = ' ';
+	}
+}
+
+
 /*
  * Unparse msgbuf tags into a buffer
  * returns the length of the tags written

modules/m_alias.c

@@ -114,7 +114,7 @@ m_alias(struct MsgBuf *msgbuf, struct Client *client_p, struct Client *source_p,
 {
 	struct Client *target_p;
 	struct alias_entry *aptr = rb_dictionary_retrieve(alias_dict, msgbuf->cmd);
-	char *p, *str;
+	char *p;
 
 	if(aptr == NULL)
 	{
@@ -151,8 +151,8 @@ m_alias(struct MsgBuf *msgbuf, struct Client *client_p, struct Client *source_p,
 		return;
 	}
 
-	str = reconstruct_parv(parc - 1, &parv[1]);
+	msgbuf_reconstruct_tail(msgbuf, 1);
-	if(EmptyString(str))
+	if(EmptyString(parv[1]))
 	{
 		sendto_one(client_p, form_str(ERR_NOTEXTTOSEND), me.name, target_p->name);
 		return;
@@ -161,5 +161,5 @@ m_alias(struct MsgBuf *msgbuf, struct Client *client_p, struct Client *source_p,
 	sendto_one(target_p, ":%s PRIVMSG %s :%s",
 			get_id(client_p, target_p),
 			p != NULL ? aptr->target : get_id(target_p, target_p),
-			str);
+			parv[1]);
 }

tests/msgbuf_parse1.c

@@ -3297,6 +3297,49 @@ static void unescape_8bit(void)
 	}
 }
 
+static struct MsgBuf *reconstruct_tail_prep(char *line, size_t n)
+{
+	static struct MsgBuf msgbuf;
+	msgbuf_init(&msgbuf);
+	msgbuf_parse(&msgbuf, line);
+	msgbuf_reconstruct_tail(&msgbuf, n);
+	return &msgbuf;
+}
+
+static void reconstruct_tail(void)
+{
+	struct MsgBuf *mb;
+	mb = reconstruct_tail_prep((char[]){"CMD P1"}, 2);
+	is_string("CMD", mb->para[0], MSG);
+	is_string("P1", mb->para[1], MSG);
+
+	mb = reconstruct_tail_prep((char[]){"CMD P1 P2"}, 2);
+	is_string("CMD", mb->para[0], MSG);
+	is_string("P1", mb->para[1], MSG);
+	is_string("P2", mb->para[2], MSG);
+
+	mb = reconstruct_tail_prep((char[]){"   CMD P1 P2 :P3"}, 0);
+	is_string("CMD P1 P2 :P3", mb->para[0], MSG);
+
+	mb = reconstruct_tail_prep((char[]){"CMD  P1 P2 :P3"}, 1);
+	is_string(" P1 P2 :P3", mb->para[1], MSG);
+
+	mb = reconstruct_tail_prep((char[]){"CMD P1   P2"}, 1);
+	is_string("P1   P2", mb->para[1], MSG);
+
+	mb = reconstruct_tail_prep((char[]){"CMD P1  P2 "}, 2);
+	is_string(" P2 ", mb->para[2], MSG);
+
+	mb = reconstruct_tail_prep((char[]){"CMD P1    "}, 2);
+	is_string("   ", mb->para[2], MSG);
+
+	mb = reconstruct_tail_prep((char[]){"CMD P1 :"}, 2);
+	is_string(":", mb->para[2], MSG);
+
+	mb = reconstruct_tail_prep((char[]){"CMD P1  :"}, 2);
+	is_string(" :", mb->para[2], MSG);
+}
+
 int main(int argc, char *argv[])
 {
 	memset(&me, 0, sizeof(me));
@@ -3411,5 +3454,7 @@ int main(int argc, char *argv[])
 
 	unescape_8bit();
 
+	reconstruct_tail();
+
 	return 0;
 }