BUG/MINOR: mux-fcgi: Don't send normalized uri to FCGI application

A normalized URI is the internal term used to specify an URI is stored using
the absolute format (scheme + authority + path). For now, it is only used
for H2 clients. It is the default and recommended format for H2 request.
However, it is unusual for H1 servers to receive such URI. So in this case,
we only send the path of the absolute URI. It is performed for H1 servers,
but not for FCGI applications. This patch fixes the difference.

Note that it is not a real bug, because FCGI applications should support
abosolute URI.

Note also a normalized URI is only detected for H2 clients when a request is
received. There is no such test on the H1 side. It means an absolute URI
received from an H1 client will be sent without modification to an H1 server
or a FCGI application.

To make it possible, a dedicated function has been added to get the H1
URI. This function is called by the H1 and the FCGI multiplexer when a
request is sent to a server.

This patch should fix the issue #1232. It must be backported as far as 2.2.

include/haproxy/h1_htx.h

@@ -27,7 +27,7 @@
 #include <haproxy/api-t.h>
 #include <haproxy/buf-t.h>
 #include <haproxy/h1.h>
-#include <haproxy/htx-t.h>
+#include <haproxy/htx.h>
 
 int h1_parse_msg_hdrs(struct h1m *h1m, union h1_sl *h1sl, struct htx *dsthtx,
 		      struct buffer *srcbuf, size_t ofs, size_t max);
@@ -37,6 +37,29 @@ int h1_parse_msg_data(struct h1m *h1m, struct htx **dsthtx,
 int h1_parse_msg_tlrs(struct h1m *h1m, struct htx *dsthtx,
 		      struct buffer *srcbuf, size_t ofs, size_t max);
 
+/* Returns the URI of an HTX message in the most common format for a H1 peer. It
+ * is the path part of an absolute URI when the URI was normalized, ortherwise
+ * it is the whole URI, as received. Concretely, it is only a special case for
+ * URIs received from H2 clients, to be able to send a relative path the H1
+ * servers.
+ */
+static inline struct ist h1_get_uri(const struct htx_sl *sl)
+{
+	struct ist uri;
+
+	uri = htx_sl_req_uri(sl);
+	if (sl->flags & HTX_SL_F_NORMALIZED_URI) {
+		uri = http_get_path(uri);
+		if (unlikely(!uri.len)) {
+			if (sl->info.req.meth == HTTP_METH_OPTIONS)
+				uri = ist("*");
+			else
+				uri = ist("/");
+		}
+	}
+	return uri;
+}
+
 int h1_format_htx_reqline(const struct htx_sl *sl, struct buffer *chk);
 int h1_format_htx_stline(const struct htx_sl *sl, struct buffer *chk);
 int h1_format_htx_hdr(const struct ist n, const struct ist v, struct buffer *chk);

src/h1_htx.c

@@ -607,17 +607,7 @@ int h1_format_htx_reqline(const struct htx_sl *sl, struct buffer *chk)
 	struct ist uri;
 	size_t sz = chk->data;
 
-	uri = htx_sl_req_uri(sl);
-	if (sl->flags & HTX_SL_F_NORMALIZED_URI) {
-		uri = http_get_path(uri);
-		if (unlikely(!uri.len)) {
-			if (sl->info.req.meth == HTTP_METH_OPTIONS)
-				uri = ist("*");
-			else
-				uri = ist("/");
-		}
-	}
-
+	uri = h1_get_uri(sl);
 	if (!chunk_memcat(chk, HTX_SL_REQ_MPTR(sl), HTX_SL_REQ_MLEN(sl)) ||
 	    !chunk_memcat(chk, " ", 1) ||
 	    !chunk_memcat(chk, uri.ptr, uri.len) ||

src/mux_fcgi.c

@@ -1239,7 +1239,7 @@ static int fcgi_set_default_param(struct fcgi_conn *fconn, struct fcgi_strm *fst
 		chunk_memcat(params->p, p.ptr, p.len);
 	}
 	if (!(params->mask & FCGI_SP_REQ_URI)) {
-		p  = htx_sl_req_uri(sl);
+		p = h1_get_uri(sl);
 		params->uri = ist2(b_tail(params->p), p.len);
 		chunk_memcat(params->p, p.ptr, p.len);
 	}