Fix race condition in TLSProxy

Normally TLSProxy waits for the s_server process to finish before
continuing. However in cases where serverconnects > 1 we need to keep the
s_server process around for a later test so we continue immediately. This
means that TAP test output can end up being printed to stdout at the same
time as s_server is printing stuff. This confuses the test runner and can
cause spurious test failures. This commit introduces a small delay in cases
where serverconnects > 1 in order to give s_server enough time to finish
what it was doing before we continue to the next test.

Fixes #4129

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4660)

diff --git a/util/perl/TLSProxy/Proxy.pm b/util/perl/TLSProxy/Proxy.pm
index f3e76bf35c457ef6cbc3691c3b69220cb7ef6cdc..83a6494933bbf2c8a064c32af0526a67cda13e30 100644 (file)
--- a/util/perl/TLSProxy/Proxy.pm
+++ b/util/perl/TLSProxy/Proxy.pm
@@ -23,6 +23,7 @@ use TLSProxy::Certificate;
 use TLSProxy::CertificateVerify;
 use TLSProxy::ServerKeyExchange;
 use TLSProxy::NewSessionTicket;
+use Time::HiRes qw/usleep/;
 
 my $have_IPv6 = 0;
 my $IP_factory;
@@ -343,6 +344,9 @@ sub clientstart
               .$self->serverpid."\n";
         waitpid( $self->serverpid, 0);
         die "exit code $? from server process\n" if $? != 0;
+    } else {
+        # Give s_server sufficient time to finish what it was doing
+        usleep(250000);
     }
     die "clientpid is zero\n" if $self->clientpid == 0;
     print "Waiting for client process to close: ".$self->clientpid."\n";