From: Christopher Faulet <cfaulet@haproxy.com>
Date: Thu, 16 Jul 2020 09:43:46 +0000 (+0200)
Subject: BUG/MEDIUM: channel: Be aware of SHUTW_NOW flag when output data are peeked
X-Git-Tag: v2.3-dev1~4
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f706a794d8b8d854cba4414adb6f9a1297c6fd02;p=thirdparty%2Fhaproxy.git

BUG/MEDIUM: channel: Be aware of SHUTW_NOW flag when output data are peeked

The CF_SHUTW_NOW flag must be handled the same way than the CF_SHUTW flag in
co_getblk_nc() and co_getline_nc() functions. It is especally important when we
try to peek a line from outgoing data. In this case, an unfinished line is
blocked an nothing is peeked if the CF_SHUTW_NOW flag is set. But the blocked
data pevent the transition to CF_SHUTW.

The above functions are only used by LUA cosockets. Because of this bug, we may
experienced wakeups in loop of the cosocket's io handler if we try to read a
line on a closed socket with a pending unfinished line (no LF found at the end).

This patch should fix issue #744. It must be backported to all supported
versions.
---

diff --git a/src/channel.c b/src/channel.c
index a3b7b9e3ea..a139eada12 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -259,7 +259,7 @@ int co_getblk(const struct channel *chn, char *blk, int len, int offset)
 int co_getblk_nc(const struct channel *chn, const char **blk1, size_t *len1, const char **blk2, size_t *len2)
 {
 	if (unlikely(co_data(chn) == 0)) {
-		if (chn->flags & CF_SHUTW)
+		if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
 			return -1;
 		return 0;
 	}
@@ -301,7 +301,7 @@ int co_getline_nc(const struct channel *chn,
 		}
 	}
 
-	if (chn->flags & CF_SHUTW) {
+	if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW)) {
 		/* If we have found no LF and the buffer is shut, then
 		 * the resulting string is made of the concatenation of
 		 * the pending blocks (1 or 2).