From 49c809e0314fc91f786791f8492bd2f2a1d525d3 Mon Sep 17 00:00:00 2001
From: Jarrod Johnson <jjohnson2@lenovo.com>
Date: Wed, 27 May 2015 10:23:37 -0400
Subject: [PATCH] Reorganize UDP <-> SSL rework

Because SSL actually was relying upon accept() to hold indefininetly,
it would hang up the UDP worker indefinitely, blocking requests.
Fix this by driving the loop iteration through select() rather than
accept() and iterating through each file handle only when select()
says they are ready.
---
 xCAT-server/sbin/xcatd | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/xCAT-server/sbin/xcatd b/xCAT-server/sbin/xcatd
index 512716e31..548c58bb9 100755
--- a/xCAT-server/sbin/xcatd
+++ b/xCAT-server/sbin/xcatd
@@ -1099,6 +1099,7 @@ while (not $listener and $retry) {
 }
 my $listenwatcher = IO::Select->new($listener);
 my $udpwatcher = IO::Select->new($udpctl);
+my $bothwatcher = IO::Select->new($udpctl, $listener);
 
 unless ($listener) {
   kill 2, $pid_UDP;
@@ -1130,6 +1131,17 @@ my $tconn;
 my $sslfudgefactor = 0;
 until ($quit) {
   $SIG{CHLD} = \&ssl_reaper; #set here to ensure that signal handler is not corrupted during loop
+  while ($udpwatcher->can_read(0)) {  # take an intermission to broker some state requests from udp traffic control
+      eval {
+          my $msg = fd_retrieve($udpctl);
+          if ($msg->{req} eq 'get_client_count') {
+            store_fd({'clientfudge'=>$sslfudgefactor, 'sslclientcount' => $sslclients}, $udpctl);
+          } elsif ($msg->{req} eq 'set_fudge_factor') {
+            $sslfudgefactor = $msg->{fudge};
+            store_fd({'clientfudge'=>$sslfudgefactor, 'sslclientcount' => $sslclients}, $udpctl);
+          }
+      };
+  }
   if (@pendingconnections) {
 	while ($listenwatcher->can_read(0)) { #grab everything we can, but don't spend any time waiting for more
 		$tconn = $listener->accept;
@@ -1137,21 +1149,16 @@ until ($quit) {
 		push @pendingconnections,$tconn;
 	}
   } else {
+    $bothwatcher->can_read(30);
+    if (not $listenwatcher->can_read(0)) {  # check for udpctl messages since
+        # we have no listen to hear
+        next;
+    }
 	$tconn = $listener->accept; #we have no connections pending, no rush, just wait until the next connection attempt comes in
 	unless ($tconn) { next; } #sometimes we get 'undef', in which case carry on with our lives...
 	push @pendingconnections,$tconn;
   }
   unless (scalar @pendingconnections) { next; } #if for some reason we landed here without any accepted connections, carry on..
-  while ($udpwatcher->can_read(0)) {  # take an intermission to broker some state requests from udp traffic control
-      eval {
-          my $msg = fd_retrieve($udpctl);
-          if ($msg->{req} eq 'get_client_count') {
-            store_fd({'clientfudge'=>$sslfudgefactor, 'sslclientcount' => $sslclients});
-          } elsif ($msg->{req} eq 'set_fudge_factor') {
-            $sslfudgefactor = $msg->{fudge};
-          }
-      };
-  }
   if ($sslclients > $maxsslclients) { #we have enough children, wait for some to exit before spawning more
       $listenwatcher->can_read(0.1); #when next connection tries to come in or a tenth of a second, whichever comes first
       next; #just keep pulling things off listen queue onto our own