From: Christopher Faulet <cfaulet@haproxy.com>
Date: Wed, 9 Jan 2019 11:16:58 +0000 (+0100)
Subject: BUG/MINOR: lua/htx: Respect the reserve when data are send from an HTX applet
X-Git-Tag: v2.0-dev1~235
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4b0e9b287061e923d68f9d7e3f71c06374eed436;p=thirdparty%2Fhaproxy.git

BUG/MINOR: lua/htx: Respect the reserve when data are send from an HTX applet

In the function hlua_applet_htx_send_yield(), there already was a test to
respect the reserve but the wrong function was used to get the available space
for data in the HTX buffer. Instead of calling htx_free_space(), the function
htx_free_data_space() must be used. But in fact, there is no reason to bother
with that anymore because the function channel_htx_recv_max() has been added for
this purpose.

The result of this bug is that the call to htx_add_data() failed unexpectedly
while the amount of written data was incremented, leading the applet to think
all data was sent. To prevent any futher bugs, a test has been added to yield if
we are not able to write data into the channel buffer.

This patch must be backported to 1.9.
---

diff --git a/src/hlua.c b/src/hlua.c
index ca51477c4b..b9df9265fb 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -4622,14 +4622,9 @@ __LJMP static int hlua_applet_htx_send_yield(lua_State *L, int status, lua_KCont
 	int l = MAY_LJMP(luaL_checkinteger(L, 3));
 	int max;
 
-	max = htx_free_space(htx);
-        if (channel_recv_limit(res) < b_size(&res->buf)) {
-                if (max < global.tune.maxrewrite) {
-			si_rx_room_blk(si);
-			MAY_LJMP(hlua_yieldk(L, 0, 0, hlua_applet_htx_send_yield, TICK_ETERNITY, 0));
-		}
-                max -= global.tune.maxrewrite;
-        }
+	max = channel_htx_recv_max(res, htx);
+	if (!max)
+		goto snd_yield;
 
 	data = MAY_LJMP(luaL_checklstring(L, 2, &len));
 
@@ -4638,8 +4633,9 @@ __LJMP static int hlua_applet_htx_send_yield(lua_State *L, int status, lua_KCont
 		max = len - l;
 
 	/* Copy data. */
-	htx_add_data(htx, ist2(data + l, max));
-	res->total += l;
+	if (!htx_add_data(htx, ist2(data + l, max)))
+		goto snd_yield;
+	res->total += max;
 	res->flags |= CF_READ_PARTIAL;
 	htx_to_buf(htx, &res->buf);
 
@@ -4652,6 +4648,7 @@ __LJMP static int hlua_applet_htx_send_yield(lua_State *L, int status, lua_KCont
 	 * applet, and returns a yield.
 	 */
 	if (l < len) {
+	  snd_yield:
 		si_rx_room_blk(si);
 		MAY_LJMP(hlua_yieldk(L, 0, 0, hlua_applet_htx_send_yield, TICK_ETERNITY, 0));
 	}