From: Eric Wong <e@80x24.org>
Date: Sun, 8 Sep 2019 10:41:12 +0000 (+0000)
Subject: nntp: regexp always consumes rbuf if "\n" exists
X-Git-Tag: v1.2.0~110
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;ds=sidebyside;h=16d96f80e55d3f40338101ee8641e03f3b4f2d64;p=public-inbox.git

nntp: regexp always consumes rbuf if "\n" exists

We don't want to get hung into a state where we see "\n" via
index(), yet cannot consume rbuf in the while loop.  So tweak
the regexp to ensure we always consume rbuf.

I suspect this is what causes occasional 100% CPU usage of
-nntpd, but reproducing it's been difficult..
---

diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index 41f1e9c1..c0496852 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -995,7 +995,7 @@ sub event_step {
 		my $off = bytes::length($$rbuf);
 		$r = $self->do_read($rbuf, LINE_MAX, $off) or return;
 	}
-	while ($r > 0 && $$rbuf =~ s/\A[ \t\r\n]*([^\r\n]*)\r?\n//) {
+	while ($r > 0 && $$rbuf =~ s/\A[ \t]*([^\n]*?)\r?\n//) {
 		my $line = $1;
 		return $self->close if $line =~ /[[:cntrl:]]/s;
 		my $t0 = now();