From: Ian Jackson <ian.jackson@eu.citrix.com>
Date: Tue, 11 Feb 2020 18:32:38 +0000 (+0000)
Subject: git-cache-proxy: Abandon fetch attempt if client disconnects
X-Git-Tag: archive/debian/6.1.2~8
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=c90b7cd9b44d02cf8c94ca92bb98266915896841;hp=d3b21a5bf9241594626cf766bdab00fd107edafc;p=chiark-utils.git

git-cache-proxy: Abandon fetch attempt if client disconnects

The git client sends the command and then waits for our response.  We
can tell if it has disconnected, because our stdin (the socket) will
be readable.

This is a good idea because otherwise if we have clients with their
own (formal or informal) timeouts, we can build up a backlog of
queued useless fetch attempts.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
---

diff --git a/scripts/git-cache-proxy b/scripts/git-cache-proxy
index 518ca9a..636ebfe 100755
--- a/scripts/git-cache-proxy
+++ b/scripts/git-cache-proxy
@@ -321,6 +321,19 @@ sub clonefetch () {
 
     if ($fetch) {
 
+	my $rbits = '';
+	vec($rbits,0,1) = 1;
+	my $ebits = $rbits;
+	my $r=select $rbits,undef,$ebits,0;
+	$r>=0 or fail "select recheck STDOUT failed: $!";
+	if ($r) {
+	    servinfo 'client disconnected (stdin unexpectedly'.
+		(vec($rbits,0,1) ? ' readable' : '').
+		(vec($ebits,0,1) ? ' exception' : '').
+		')';
+	    exit 0;
+	}
+
 	our @cmd;
 
 	if (!$exists) {