--- loncom/loncnew	2003/06/03 01:59:39	1.7
+++ loncom/loncnew	2004/09/22 10:22:50	1.57
@@ -2,13 +2,12 @@
 # The LearningOnline Network with CAPA
 # lonc maintains the connections to remote computers
 #
-# $Id: loncnew,v 1.7 2003/06/03 01:59:39 foxr Exp $
+# $Id: loncnew,v 1.57 2004/09/22 10:22:50 foxr Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
 # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
-#
-# LON-CAPA is free software; you can redistribute it and/or modify
+## LON-CAPA is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 2 of the License, or
 # (at your option) any later version.
@@ -27,7 +26,7 @@
 # http://www.lon-capa.org/
 #
 #
-# new lonc handles n requestors spread out bver m connections to londs.
+# new lonc handles n request out bver m connections to londs.
 # This module is based on the Event class.
 #   Development iterations:
 #    - Setup basic event loop.   (done)
@@ -36,28 +35,23 @@
 #    - Add ability to create/negotiate lond connections (done).
 #    - Add general logic for dispatching requests and timeouts. (done).
 #    - Add support for the lonc/lond requests.          (done).
-#    - Add logging/status monitoring.
-#    - Add Signal handling - HUP restarts. USR1 status report.
+#    - Add logging/status monitoring.                    (done)
+#    - Add Signal handling - HUP restarts. USR1 status report. (done)
 #    - Add Configuration file I/O                       (done).
-#    - Add Pending request processing on startup.
-#    - Add management/status request interface.
-#    - Add deferred request capability.
-#
-
-# Change log:
-#    $Log: loncnew,v $
-#    Revision 1.7  2003/06/03 01:59:39  foxr
-#    complete coding to support deferred transactions.
-#
+#    - Add management/status request interface.         (done)
+#    - Add deferred request capability.                  (done)
+#    - Detect transmission timeouts.                     (done)
 #
 
+use strict;
 use lib "/home/httpd/lib/perl/";
-use lib "/home/foxr/newloncapa/types";
 use Event qw(:DEFAULT );
 use POSIX qw(:signal_h);
+use POSIX;
 use IO::Socket;
 use IO::Socket::INET;
 use IO::Socket::UNIX;
+use IO::File;
 use IO::Handle;
 use Socket;
 use Crypt::IDEA;
@@ -68,18 +62,6 @@ use LONCAPA::LondTransaction;
 use LONCAPA::Configuration;
 use LONCAPA::HashIterator;
 
-print "Loncnew starting\n";
-
-#
-#   Disable all signals we might receive from outside for now.
-#
-$SIG{QUIT}  = IGNORE;
-$SIG{HUP}   = IGNORE;
-$SIG{USR1}  = IGNORE;
-$SIG{INT}   = IGNORE;
-$SIG{CHLD}  = IGNORE;
-$SIG{__DIE__}  = IGNORE;
-
 
 # Read the httpd configuration file to get perl variables
 # normally set in apache modules:
@@ -91,35 +73,134 @@ my %perlvar    = %{$perlvarref};
 #  parent and shared variables.
 
 my %ChildHash;			# by pid -> host.
+my %HostToPid;			# By host -> pid.
+my %HostHash;			# by loncapaname -> IP.
 
 
-my $MaxConnectionCount = 5;	# Will get from config later.
+my $MaxConnectionCount = 10;	# Will get from config later.
 my $ClientConnection = 0;	# Uniquifier for client events.
 
-my $DebugLevel = 5;
-my $IdleTimeout= 3600;		# Wait an hour before pruning connections.
+my $DebugLevel = 0;
+my $NextDebugLevel= 2;		# So Sigint can toggle this.
+my $IdleTimeout= 600;		# Wait 10 minutes before pruning connections.
+
+my $LogTransactions = 0;	# When True, all transactions/replies get logged.
 
 #
 #  The variables below are only used by the child processes.
 #
 my $RemoteHost;			# Name of host child is talking to.
-my $UnixSocketDir= "/home/httpd/sockets"; 
+my $UnixSocketDir= $perlvar{'lonSockDir'};
 my $IdleConnections = Stack->new(); # Set of idle connections
 my %ActiveConnections;		# Connections to the remote lond.
 my %ActiveTransactions;		# LondTransactions in flight.
 my %ActiveClients;		# Serial numbers of active clients by socket.
 my $WorkQueue       = Queue->new(); # Queue of pending transactions.
-#  my $ClientQueue     = Queue->new(); # Queue of clients causing xactinos.
 my $ConnectionCount = 0;
 my $IdleSeconds     = 0;	# Number of seconds idle.
+my $Status          = "";	# Current status string.
+my $RecentLogEntry  = "";
+my $ConnectionRetries=2;	# Number of connection retries allowed.
+my $ConnectionRetriesLeft=2;	# Number of connection retries remaining.
+my $LondVersion     = "unknown"; # Version of lond we talk with.
+my $KeyMode         = "";       # e.g. ssl, local, insecure from last connect.
+my $LondConnecting  = 0;       # True when a connection is being built.
+
+my $DieWhenIdle     = 0;	# When true children die when trimmed -> 0.
+
+#
+#   The hash below gives the HTML format for log messages
+#   given a severity.
+#    
+my %LogFormats;
+
+$LogFormats{"CRITICAL"} = "<font color='red'>CRITICAL: %s</font>";
+$LogFormats{"SUCCESS"}  = "<font color='green'>SUCCESS: %s</font>";
+$LogFormats{"INFO"}     = "<font color='yellow'>INFO: %s</font>";
+$LogFormats{"WARNING"}  = "<font color='blue'>WARNING: %s</font>";
+$LogFormats{"DEFAULT"}  = " %s ";
+
+
+#  UpdateStatus;
+#    Update the idle status display to show how many connections
+#    are left, retries and other stuff.
+#
+sub UpdateStatus {
+    if ($ConnectionRetriesLeft > 0) {
+	ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
+		   ." Retries remaining: ".$ConnectionRetriesLeft
+		   ." ($KeyMode)");
+    } else {
+	ShowStatus(GetServerHost()." >> DEAD <<");
+    }
+}
 
-#
-#   This disconnected socket makes posible a bit more regular
-#   code when processing delayed requests:
-#
-my $NullSocket = IO::Socket->new();
 
-#
+=pod
+
+=head2 LogPerm
+
+Makes an entry into the permanent log file.
+
+=cut
+sub LogPerm {
+    my $message=shift;
+    my $execdir=$perlvar{'lonDaemons'};
+    my $now=time;
+    my $local=localtime($now);
+    my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
+    print $fh "$now:$message:$local\n";
+}
+
+=pod
+
+=head2 Log
+
+Logs a message to the log file.
+Parameters:
+
+=item severity
+
+One of CRITICAL, WARNING, INFO, SUCCESS used to select the
+format string used to format the message.  if the severity is
+not a defined severity the Default format string is used.
+
+=item message
+
+The base message.  In addtion to the format string, the message
+will be appended to a string containing the name of our remote
+host and the time will be formatted into the message.
+
+=cut
+
+sub Log {
+
+    my ($severity, $message) = @_;
+
+    if(!$LogFormats{$severity}) {
+	$severity = "DEFAULT";
+    }
+
+    my $format = $LogFormats{$severity};
+    
+    #  Put the window dressing in in front of the message format:
+
+    my $now   = time;
+    my $local = localtime($now);
+    my $finalformat = "$local ($$) [$RemoteHost] [$Status] ";
+    my $finalformat = $finalformat.$format."\n";
+
+    # open the file and put the result.
+
+    my $execdir = $perlvar{'lonDaemons'};
+    my $fh      = IO::File->new(">>$execdir/logs/lonc.log");
+    my $msg = sprintf($finalformat, $message);
+    $RecentLogEntry = $msg;
+    print $fh $msg;
+    
+    
+}
+
 
 =pod
 
@@ -130,14 +211,16 @@ Returns the name of the host that a sock
 =cut
 
 sub GetPeername {
-    my $connection = shift;
-    my $AdrFamily  = shift;
+
+
+    my ($connection, $AdrFamily) = @_;
+
     my $peer       = $connection->peername();
     my $peerport;
     my $peerip;
     if($AdrFamily == AF_INET) {
 	($peerport, $peerip) = sockaddr_in($peer);
-	my $peername    = gethostbyaddr($iaddr, $AdrFamily);
+	my $peername    = gethostbyaddr($peerip, $AdrFamily);
 	return $peername;
     } elsif ($AdrFamily == AF_UNIX) {
 	my $peerfile;
@@ -145,7 +228,6 @@ sub GetPeername {
 	return $peerfile;
     }
 }
-#----------------------------- Timer management ------------------------
 =pod
 
 =head2 Debug
@@ -155,18 +237,20 @@ Invoked to issue a debug message.
 =cut
 
 sub Debug {
-    my $level   = shift;
-    my $message = shift;
+
+    my ($level, $message) = @_;
+
     if ($level <= $DebugLevel) {
-	print $message." host = ".$RemoteHost."\n";
+	Log("INFO", "-Debug- $message host = $RemoteHost");
     }
 }
 
 sub SocketDump {
-    my $level = shift;
-    my $socket= shift;
+
+    my ($level, $socket) = @_;
+
     if($level <= $DebugLevel) {
-	$socket->Dump();
+	$socket->Dump(-1);	# Ensure it will get dumped.
     }
 }
 
@@ -175,12 +259,44 @@ sub SocketDump {
 =head2 ShowStatus
 
  Place some text as our pid status.
+ and as what we return in a SIGUSR1
 
 =cut
 sub ShowStatus {
-    my $status = shift;
-    $0 =  "lonc: ".$status;
+    my $state = shift;
+    my $now = time;
+    my $local = localtime($now);
+    $Status   = $local.": ".$state;
+    $0='lonc: '.$state.' '.$local;
+}
+
+=pod
+
+=head 2 SocketTimeout
+
+    Called when an action on the socket times out.  The socket is 
+   destroyed and any active transaction is failed.
+
+
+=cut
+sub SocketTimeout {
+    my $Socket = shift;
+    Log("WARNING", "A socket timeout was detected");
+    Debug(5, " SocketTimeout called: ");
+    $Socket->Dump(0);
+    if(exists($ActiveTransactions{$Socket})) {
+	FailTransaction($ActiveTransactions{$Socket});
+    }
+    KillSocket($Socket);	# A transaction timeout also counts as
+                                # a connection failure:
+    $ConnectionRetriesLeft--;
+    if($ConnectionRetriesLeft <= 0) {
+	Log("CRITICAL", "Host marked DEAD: ".GetServerHost());
+	$LondConnecting = 0;
+    }
+
 }
+#----------------------------- Timer management ------------------------
 
 =pod
 
@@ -192,13 +308,12 @@ Invoked  each timer tick.
 
 
 sub Tick {
+    my ($Event)       = @_;
+    my $clock_watcher = $Event->w;
+
     my $client;
-    ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount);
-    Debug(6, "Tick");
-    Debug(6, "    Current connection count: ".$ConnectionCount);
-    foreach $client (keys %ActiveClients) {
-	Debug(7, "    Have client:  with id: ".$ActiveClients{$client});
-    }
+    UpdateStatus();
+
     # Is it time to prune connection count:
 
 
@@ -206,27 +321,68 @@ sub Tick {
        ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
 	$IdleSeconds++;
 	if($IdleSeconds > $IdleTimeout) { # Prune a connection...
-	    $Socket = $IdleConnections->pop();
+	    my $Socket = $IdleConnections->pop();
 	    KillSocket($Socket);
+	    $IdleSeconds = 0;	# Otherwise all connections get trimmed to fast.
+	    UpdateStatus();
+	    if(($ConnectionCount == 0) && $DieWhenIdle) {
+		#
+		#  Create a lock file since there will be a time window
+		#  between our exit and the parent's picking up the listen
+		#  during which no listens will be done on the
+		#  lonnet client socket.
+		#
+		my $lock_file = GetLoncSocketPath().".lock";
+		open(LOCK,">$lock_file");
+		print LOCK "Contents not important";
+		close(LOCK);
+		
+		exit(0);
+	    }
 	}
     } else {
 	$IdleSeconds = 0;	# Reset idle count if not idle.
     }
+    #
+    #  For each inflight transaction, tick down its timeout counter.
+    #
 
+    foreach my $item (keys %ActiveConnections) {
+	my $State = $ActiveConnections{$item}->data->GetState();
+	if ($State ne 'Idle') {
+	    Debug(5,"Ticking Socket $State $item");
+	    $ActiveConnections{$item}->data->Tick();
+	}
+    }
     # Do we have work in the queue, but no connections to service them?
     # If so, try to make some new connections to get things going again.
     #
-    
+    #   Note this code is dead now...
+    #
     my $Requests = $WorkQueue->Count();
-    if (($ConnectionCount == 0)  && ($Requests > 0)) {
-	my $Connections = ($Requests <= $MaxConnectionCount) ?
-	                           $Requests : $MaxConnectionCount;
-	Debug(1,"Work but no connections, starting ".$Connections." of them");
-	for ($i =0; $i < $Connections; $i++) {
-	    MakeLondConnection();
+    if (($ConnectionCount == 0)  && ($Requests > 0) && (!$LondConnecting)) { 
+	if ($ConnectionRetriesLeft > 0) {
+	    Debug(5,"Work but no connections, Make a new one");
+	    my $success;
+	    $success    = &MakeLondConnection;
+	    if($success == 0) { # All connections failed:
+		Debug(5,"Work in queue failed to make any connectiouns\n");
+		EmptyQueue();	# Fail pending transactions with con_lost.
+		CloseAllLondConnections(); # Should all be closed but....
+	    }
+	} else {
+	    $LondConnecting = 0;
+	    ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
+	    Debug(5,"Work in queue, but gave up on connections..flushing\n");
+	    EmptyQueue();	# Connections can't be established.
+	    CloseAllLondConnections(); # Should all already be closed but...
 	}
        
     }
+    if ($ConnectionCount == 0) {
+	$KeyMode = ""; 
+	$clock_watcher->cancel();
+    }
 }
 
 =pod
@@ -247,7 +403,7 @@ Trigger disconnections of idle sockets.
 
 sub SetupTimer {
     Debug(6, "SetupTimer");
-    Event->timer(interval => 1, debug => 1, cb => \&Tick );
+    Event->timer(interval => 1, cb => \&Tick );
 }
 
 =pod
@@ -267,20 +423,22 @@ long enough, it will be shut down and re
 
 sub ServerToIdle {
     my $Socket   = shift;	# Get the socket.
+    $KeyMode = $Socket->{AuthenticationMode};
     delete($ActiveTransactions{$Socket}); # Server has no transaction
 
-    &Debug(6, "Server to idle");
+    &Debug(5, "Server to idle");
 
     #  If there's work to do, start the transaction:
 
-    $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
-    unless($reqdata eq undef)  {
-	Debug(9, "Queue gave request data: ".$reqdata->getRequest());
+    my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
+    if ($reqdata ne undef)  {
+	Debug(5, "Queue gave request data: ".$reqdata->getRequest());
 	&StartRequest($Socket,  $reqdata);
+
     } else {
 	
     #  There's no work waiting, so push the server to idle list.
-	&Debug(8, "No new work requests, server connection going idle");
+	&Debug(5, "No new work requests, server connection going idle");
 	$IdleConnections->push($Socket);
     }
 }
@@ -326,7 +484,7 @@ sub ClientWritable {
 	# request.
 	
 	&Debug(9,"Send result is ".$result." Defined: ".defined($result));
-	if(defined($result)) {
+	if($result ne undef) {
 	    &Debug(9, "send result was defined");
 	    if($result == length($Data)) { # Entire string sent.
 		&Debug(9, "ClientWritable data all written");
@@ -344,6 +502,12 @@ sub ClientWritable {
 		
 	    } else {		# Partial string sent.
 		$Watcher->data(substr($Data, $result));
+		if($result == 0) {    # client hung up on us!!
+		    # Log("INFO", "lonc pipe client hung up on us!");
+		    $Watcher->cancel;
+		    $Socket->shutdown(2);
+		    $Socket->close();
+		}
 	    }
 	    
 	} else {			# Error of some sort...
@@ -391,18 +555,25 @@ The transaction that is being completed.
 =cut
 
 sub CompleteTransaction {
-    &Debug(6,"Complete transaction");
-    my $Socket = shift;
-    my $Transaction = shift;
+    &Debug(5,"Complete transaction");
+
+    my ($Socket, $Transaction) = @_;
 
     if (!$Transaction->isDeferred()) { # Normal transaction
 	my $data   = $Socket->GetReply(); # Data to send.
+	if($LogTransactions) {
+	    Log("SUCCESS", "Reply from lond: '$data'");
+	}
 	StartClientReply($Transaction, $data);
     } else {			# Delete deferred transaction file.
+	Log("SUCCESS", "A delayed transaction was completed");
+	LogPerm("S:$Transaction->getClient() :".$Transaction->getRequest());
 	unlink $Transaction->getFile();
     }
 }
+
 =pod
+
 =head1 StartClientReply
 
    Initiates a reply to a client where the reply data is a parameter.
@@ -418,16 +589,16 @@ sub CompleteTransaction {
     The data to send to apached client.
 
 =cut
+
 sub StartClientReply {
-    my $Transaction   = shift;
-    my $data     = shift;
+
+    my ($Transaction, $data) = @_;
 
     my $Client   = $Transaction->getClient();
 
     &Debug(8," Reply was: ".$data);
     my $Serial         = $ActiveClients{$Client};
     my $desc           = sprintf("Connection to lonc client %d",
-
 				 $Serial);
     Event->io(fd       => $Client,
 	      poll     => "w",
@@ -435,7 +606,9 @@ sub StartClientReply {
 	      cb       => \&ClientWritable,
 	      data     => $data);
 }
+
 =pod
+
 =head2 FailTransaction
 
   Finishes a transaction with failure because the associated lond socket
@@ -445,8 +618,7 @@ sub StartClientReply {
   - The transaction is 'live' in which case we initiate the sending
     of "con_lost" to the client.
 
-Deleting the transaction means killing it from the 
-%ActiveTransactions hash.
+Deleting the transaction means killing it from the %ActiveTransactions hash.
 
 Parameters:
 
@@ -454,17 +626,24 @@ Parameters:
  
    The LondTransaction we are failing.
  
+
 =cut
 
 sub FailTransaction {
     my $transaction = shift;
-    my $Lond        = $transaction->getServer();
-    if (!$client->isDeferred()) { # If the transaction is deferred we'll get to it.
-	my $client  = $transcation->getClient();
-	StartClientReply($client, "con_lost");
+    
+    #  If the socket is dead, that's already logged.
+
+    if ($ConnectionRetriesLeft > 0) {
+	Log("WARNING", "Failing transaction "
+	    .$transaction->getRequest());
+    }
+    Debug(1, "Failing transaction: ".$transaction->getRequest());
+    if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
+	my $client  = $transaction->getClient();
+	Debug(1," Replying con_lost to ".$transaction->getRequest());
+	StartClientReply($transaction, "con_lost\n");
     }
-# not needed, done elsewhere if active.
-#    delete $ActiveTransactions{$Lond};
 
 }
 
@@ -476,14 +655,32 @@ sub FailTransaction {
 
 =cut
 sub EmptyQueue {
+    $ConnectionRetriesLeft--;	# Counts as connection failure too.
     while($WorkQueue->Count()) {
-	my $request = $Workqueue->dequeue(); # This is a transaction
+	my $request = $WorkQueue->dequeue(); # This is a transaction
 	FailTransaction($request);
     }
 }
 
 =pod
 
+=head2 CloseAllLondConnections
+
+Close all connections open on lond prior to exit e.g.
+
+=cut
+sub CloseAllLondConnections {
+    foreach my $Socket (keys %ActiveConnections) {
+      if(exists($ActiveTransactions{$Socket})) {
+	FailTransaction($ActiveTransactions{$Socket});
+      }
+      KillSocket($Socket);
+    }
+}
+=cut
+
+=pod
+
 =head2 KillSocket
  
 Destroys a socket.  This function can be called either when a socket
@@ -507,6 +704,9 @@ nonzero if we are allowed to create a ne
 sub KillSocket {
     my $Socket = shift;
 
+    Log("WARNING", "Shutting down a socket");
+    $Socket->Shutdown();
+
     #  If the socket came from the active connection set,
     #  delete its transaction... note that FailTransaction should
     #  already have been called!!!
@@ -518,14 +718,15 @@ sub KillSocket {
     }
     if(exists($ActiveConnections{$Socket})) {
 	delete($ActiveConnections{$Socket});
+	$ConnectionCount--;
+	if ($ConnectionCount < 0) { $ConnectionCount = 0; }
     }
-    $ConnectionCount--;
-
     #  If the connection count has gone to zero and there is work in the
     #  work queue, the work all gets failed with con_lost.
     #
     if($ConnectionCount == 0) {
-	EmptyQueue;
+	EmptyQueue();
+	CloseAllLondConnections; # Should all already be closed but...
     }
 }
 
@@ -551,6 +752,17 @@ The connection must echo the challenge b
 The challenge has been replied to.  The we are receiveing the 
 'ok' from the partner.
 
+=head3  State=ReadingVersionString
+
+We have requested the lond version and are reading the
+version back.  Upon completion, we'll store the version away
+for future use(?).
+
+=head3 State=HostSet
+
+We have selected the domain name of our peer (multhomed hosts)
+and are getting the reply (presumably ok) back.
+
 =head3 State=RequestingKey
 
 The ok has been received and we need to send the request for
@@ -588,27 +800,39 @@ transaction is in progress, the socket a
 =cut
 
 sub LondReadable {
+
     my $Event      = shift;
     my $Watcher    = $Event->w;
     my $Socket     = $Watcher->data;
     my $client     = undef;
 
+    &Debug(6,"LondReadable called state = ".$Socket->GetState());
+
 
     my $State = $Socket->GetState(); # All action depends on the state.
 
-    &Debug(6,"LondReadable called state = ".$State);
     SocketDump(6, $Socket);
+    my $status = $Socket->Readable();
+
+    &Debug(2, "Socket->Readable returned: $status");
 
-    if($Socket->Readable() != 0) {
-	 # bad return from socket read. Currently this means that
+    if($status != 0) {
+	# bad return from socket read. Currently this means that
 	# The socket has become disconnected. We fail the transaction.
 
+	Log("WARNING",
+	    "Lond connection lost.");
 	if(exists($ActiveTransactions{$Socket})) {
-	    Debug(3,"Lond connection lost failing transaction");
 	    FailTransaction($ActiveTransactions{$Socket});
+	} else {
+	    #  Socket is connecting and failed... need to mark
+	    #  no longer connecting.
+	   
+	    $LondConnecting = 0;
 	}
 	$Watcher->cancel();
 	KillSocket($Socket);
+	$ConnectionRetriesLeft--;       # Counts as connection failure
 	return;
     }
     SocketDump(6,$Socket);
@@ -616,39 +840,73 @@ sub LondReadable {
     $State = $Socket->GetState(); # Update in case of transition.
     &Debug(6, "After read, state is ".$State);
 
-   if($State eq "Initialized") {
+    if($State eq "Initialized") {
 
 
     } elsif ($State eq "ChallengeReceived") {
 	#  The challenge must be echoed back;  The state machine
 	# in the connection takes care of setting that up.  Just
 	# need to transition to writable:
-
-	$Watcher->poll("w");
+	
 	$Watcher->cb(\&LondWritable);
+	$Watcher->poll("w");
 
     } elsif ($State eq "ChallengeReplied") {
 
+    } elsif ($State eq "RequestingVersion") {
+	# Need to ask for the version... that is writiability:
+
+	$Watcher->cb(\&LondWritable);
+	$Watcher->poll("w");
+
+    } elsif ($State eq "ReadingVersionString") {
+	# Read the rest of the version string... 
+    } elsif ($State eq "SetHost") {
+	# Need to request the actual domain get set...
+
+	$Watcher->cb(\&LondWritable);
+	$Watcher->poll("w");
+    } elsif ($State eq "HostSet") {
+	# Reading the 'ok' from the peer.
 
     } elsif ($State eq "RequestingKey") {
 	#  The ok was received.  Now we need to request the key
 	#  That requires us to be writable:
 
-	$Watcher->poll("w");
 	$Watcher->cb(\&LondWritable);
+	$Watcher->poll("w");
 
     } elsif ($State eq "ReceivingKey") {
 
     } elsif ($State eq "Idle") {
+   
+	# This is as good a spot as any to get the peer version
+	# string:
+   
+	if($LondVersion eq "unknown") {
+	    $LondVersion = $Socket->PeerVersion();
+	    Log("INFO", "Connected to lond version: $LondVersion");
+	}
 	# If necessary, complete a transaction and then go into the
 	# idle queue.
+	#  Note that a trasition to idle indicates a live lond
+	# on the other end so reset the connection retries.
+	#
+	$ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
+	$Watcher->cancel();
 	if(exists($ActiveTransactions{$Socket})) {
-	    Debug(8,"Completing transaction!!");
+	    Debug(5,"Completing transaction!!");
 	    CompleteTransaction($Socket, 
 				$ActiveTransactions{$Socket});
+	} else {
+	    Log("SUCCESS", "Connection ".$ConnectionCount." to "
+		.$RemoteHost." now ready for action");
 	}
-	$Watcher->cancel();
 	ServerToIdle($Socket);	# Next work unit or idle.
+
+	#
+	$LondConnecting = 0;	# Best spot I can think of for this.
+	# 
 	
     } elsif ($State eq "SendingRequest") {
 	#  We need to be writable for this and probably don't belong
@@ -662,7 +920,7 @@ sub LondReadable {
 
 
     } else {
-	 # Invalid state.
+	# Invalid state.
 	Debug(4, "Invalid state in LondReadable");
     }
 }
@@ -731,102 +989,116 @@ is the socket on which to return a reply
 sub LondWritable {
     my $Event   = shift;
     my $Watcher = $Event->w;
-    my @data    = $Watcher->data;
-    Debug(6,"LondWritable State = ".$State." data has ".@data." elts.\n");
+    my $Socket  = $Watcher->data;
+    my $State   = $Socket->GetState();
 
-    my $Socket  = $data;	# I know there's at least a socket.
+    Debug(6,"LondWritable State = ".$State."\n");
 
+ 
     #  Figure out what to do depending on the state of the socket:
     
 
-    my $State   = $Socket->GetState();
 
 
     SocketDump(6,$Socket);
 
-    if      ($State eq "Connected")         {
+    #  If the socket is writable, we must always write.
+    # Only by writing will we undergo state transitions.
+    # Old logic wrote in state specific code below, however
+    # That forces us at least through another invocation of
+    # this function after writability is possible again.
+    # This logic also factors out common code for handling
+    # write failures... in all cases, write failures 
+    # Kill the socket.
+    #  This logic makes the branches of the >big< if below
+    # so that the writing states are actually NO-OPs.
+
+    if ($Socket->Writable() != 0) {
+	#  The write resulted in an error.
+	# We'll treat this as if the socket got disconnected:
+	Log("WARNING", "Connection to ".$RemoteHost.
+	    " has been disconnected");
+	if(exists($ActiveTransactions{$Socket})) {
+	    FailTransaction($ActiveTransactions{$Socket});
+	} else {
+	    #  In the process of conneting, so need to turn that off.
+	    
+	    $LondConnecting = 0;
+	}
+	$Watcher->cancel();
+	KillSocket($Socket);
+	return;
+    }
 
-	if ($Socket->Writable() != 0) {
-	    #  The write resulted in an error.
-	    # We'll treat this as if the socket got disconnected:
 
-	    $Watcher->cancel();
-	    KillSocket($Socket);
-	    return;
-	}
-	#  "init" is being sent...
 
-	
+    if      ($State eq "Connected")         {
+
+	#  "init" is being sent...
+ 
     } elsif ($State eq "Initialized")       {
 
 	# Now that init was sent, we switch 
 	# to watching for readability:
 
-	$Watcher->poll("r");
 	$Watcher->cb(\&LondReadable);
-
+	$Watcher->poll("r");
+	
     } elsif ($State eq "ChallengeReceived") {
 	# We received the challenge, now we 
 	# are echoing it back. This is a no-op,
 	# we're waiting for the state to change
 	
-	if($Socket->Writable() != 0) {
-
-	    $Watcher->cancel();
-	    KillSocket($Socket);
-	    return;
-	}
-	
     } elsif ($State eq "ChallengeReplied")  {
 	# The echo was sent back, so we switch
 	# to watching readability.
 
+	$Watcher->cb(\&LondReadable);
+	$Watcher->poll("r");
+    } elsif ($State eq "RequestingVersion") {
+	# Sending the peer a version request...
+
+    } elsif ($State eq "ReadingVersionString") {
+	# Transition to read since we have sent the
+	# version command and now just need to read the
+	# version string from the peer:
+      
+	$Watcher->cb(\&LondReadable);
 	$Watcher->poll("r");
+      
+    } elsif ($State eq "SetHost") {
+	#  Setting the remote domain...
+
+    } elsif ($State eq "HostSet") {
+	# Back to readable to get the ok.
+      
 	$Watcher->cb(\&LondReadable);
+	$Watcher->poll("r");
+      
 
     } elsif ($State eq "RequestingKey")     {
 	# At this time we're requesting the key.
 	# again, this is essentially a no-op.
-	# we'll write the next chunk until the
-	# state changes.
-
-	if($Socket->Writable() != 0) {
-	    # Write resulted in an error.
 
-	    $Watcher->cancel();
-	    KillSocket($Socket);
-	    return;
-
-	}
     } elsif ($State eq "ReceivingKey")      {
 	# Now we need to wait for the key
 	# to come back from the peer:
 
-	$Watcher->poll("r");
 	$Watcher->cb(\&LondReadable);
+	$Watcher->poll("r");
 
     } elsif ($State eq "SendingRequest")    {
+ 
 	# At this time we are sending a request to the
 	# peer... write the next chunk:
 
-	if($Socket->Writable() != 0) {
-
-	    if(exists($ActiveTransactions{$Socket})) {
-		Debug(3, "Lond connection lost, failing transactions");
-		FailTransaction($ActiveTransactions{$Socket});
-	    }
-	    $Watcher->cancel();
-	    KillSocket($Socket);
-	    return;
-	    
-	}
 
     } elsif ($State eq "ReceivingReply")    {
 	# The send has completed.  Wait for the
 	# data to come in for a reply.
 	Debug(8,"Writable sent request/receiving reply");
-	$Watcher->poll("r");
 	$Watcher->cb(\&LondReadable);
+	$Watcher->poll("r");
 
     } else {
 	#  Control only passes here on an error: 
@@ -842,17 +1114,24 @@ sub LondWritable {
     
 =cut
 sub QueueDelayed {
+    Debug(3,"QueueDelayed called");
+
     my $path = "$perlvar{'lonSockDir'}/delayed";
+
+    Debug(4, "Delayed path: ".$path);
     opendir(DIRHANDLE, $path);
-    @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
+    
+    my @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
     closedir(DIRHANDLE);
     my $dfname;
-    my $reqfile
-    foreach $reqfile (sort @alldelayed) {
-	$reqfile = $path/$reqfile;
+    my $reqfile;
+    foreach $dfname (sort  @alldelayed) {
+	$reqfile = "$path/$dfname";
+	Debug(4, "queueing ".$reqfile);
 	my $Handle = IO::File->new($reqfile);
 	my $cmd    = <$Handle>;
-	chomp($cmd);
+	chomp $cmd;		# There may or may not be a newline...
+	$cmd = $cmd."\n";	# now for sure there's exactly one newline.
 	my $Transaction = LondTransaction->new($cmd);
 	$Transaction->SetDeferred($reqfile);
 	QueueTransaction($Transaction);
@@ -879,33 +1158,44 @@ sub MakeLondConnection {
     my $Connection = LondConnection->new(&GetServerHost(),
 					 &GetServerPort());
 
-    if($Connection == undef) {	# Needs to be more robust later.
-	Debug(0,"Failed to make a connection with lond.");
+    if($Connection eq undef) {	# Needs to be more robust later.
+	Log("CRITICAL","Failed to make a connection with lond.");
+	$ConnectionRetriesLeft--;
+	return 0;		# Failure.
     }  else {
+
 	# The connection needs to have writability 
 	# monitored in order to send the init sequence
 	# that starts the whole authentication/key
 	# exchange underway.
 	#
 	my $Socket = $Connection->GetSocket();
-	if($Socket == undef) {
+	if($Socket eq undef) {
 	    die "did not get a socket from the connection";
 	} else {
 	    &Debug(9,"MakeLondConnection got socket: ".$Socket);
 	}
 	
-	
-	$event = Event->io(fd       => $Socket,
+	$Connection->SetTimeoutCallback(\&SocketTimeout);
+
+	my $event = Event->io(fd       => $Socket,
 			   poll     => 'w',
 			   cb       => \&LondWritable,
-			   data     => \$Connection,
+			   data     => $Connection,
 			   desc => 'Connection to lond server');
 	$ActiveConnections{$Connection} = $event;
-	
+	if ($ConnectionCount == 0) {
+	    &SetupTimer;	# Need to handle timeouts with connections...
+	}
 	$ConnectionCount++;
+	Debug(4, "Connection count = ".$ConnectionCount);
 	if($ConnectionCount == 1) { # First Connection:
 	    QueueDelayed;
 	}
+	Log("SUCESS", "Created connection ".$ConnectionCount
+	    ." to host ".GetServerHost());
+	$LondConnecting = 1;	# Connection in progress.
+	return 1;		# Return success.
     }
     
 }
@@ -936,8 +1226,8 @@ The text of the request to send.
 =cut
 
 sub StartRequest {
-    my $Lond     = shift;
-    my $Request  = shift;	# This is a LondTransaction.
+
+    my ($Lond, $Request) = @_;
     
     Debug(6, "StartRequest: ".$Request->getRequest());
 
@@ -947,7 +1237,7 @@ sub StartRequest {
     $ActiveTransactions{$Lond} = $Request;
 
     $Lond->InitiateTransaction($Request->getRequest());
-    $event = Event->io(fd      => $Lond->GetSocket(),
+    my $event = Event->io(fd      => $Socket,
 		       poll    => "w",
 		       cb      => \&LondWritable,
 		       data    => $Lond,
@@ -986,11 +1276,23 @@ sub QueueTransaction {
 
     my $LondSocket    = $IdleConnections->pop();
     if(!defined $LondSocket) {	# Need to queue request.
-	Debug(8,"Must queue...");
+	Debug(5,"Must queue...");
 	$WorkQueue->enqueue($requestData);
-	if($ConnectionCount < $MaxConnectionCount) {
-	    Debug(4,"Starting additional lond connection");
-	    MakeLondConnection();
+	Debug(5, "Queue Transaction startnew $ConnectionCount $LondConnecting");
+	if(($ConnectionCount < $MaxConnectionCount)   && (! $LondConnecting)) {
+
+	    if($ConnectionRetriesLeft > 0) {
+		Debug(5,"Starting additional lond connection");
+		if(&MakeLondConnection() == 0) {
+		    EmptyQueue();	# Fail transactions, can't make connection.
+		    CloseAllLondConnections; # Should all be closed but...
+		}
+	    } else {
+		ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
+		$LondConnecting = 0;
+		EmptyQueue();	# It's worse than that ... he's dead Jim.
+		CloseAllLondConnections; # Should all be closed but..
+	    }
 	}
     } else {			# Can start the request:
 	Debug(8,"Can start...");
@@ -1003,7 +1305,6 @@ sub QueueTransaction {
 =pod
 
 =head2 ClientRequest
-
 Callback that is called when data can be read from the UNIX domain
 socket connecting us with an apache server process.
 
@@ -1022,19 +1323,29 @@ sub ClientRequest {
     my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
     Debug(8, "rcv:  data length = ".length($thisread)
 	  ." read =".$thisread);
-    unless (defined $rv && length($thisread)) {
+    unless (defined $rv  && length($thisread)) {
 	 # Likely eof on socket.
 	Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
 	close($socket);
 	$watcher->cancel();
 	delete($ActiveClients{$socket});
+	return;
     }
     Debug(8,"Data: ".$data." this read: ".$thisread);
     $data = $data.$thisread;	# Append new data.
     $watcher->data($data);
-    if($data =~ /(.*\n)/) {	# Request entirely read.
+    if($data =~ /\n$/) {	# Request entirely read.
+	if($data eq "close_connection_exit\n") {
+	    Log("CRITICAL",
+		"Request Close Connection ... exiting");
+	    CloseAllLondConnections();
+	    exit;
+	}
 	Debug(8, "Complete transaction received: ".$data);
-	my $Transaction = new LondTransaction->new($data);
+	if($LogTransactions) {
+	    Log("SUCCESS", "Transaction: '$data'"); # Transaction has \n.
+	}
+	my $Transaction = LondTransaction->new($data);
 	$Transaction->SetClient($socket);
 	QueueTransaction($Transaction);
 	$watcher->cancel();	# Done looking for input data.
@@ -1132,7 +1443,7 @@ sub SetupLoncListener {
     my $SocketName = GetLoncSocketPath();
     unlink($SocketName);
     unless ($socket =IO::Socket::UNIX->new(Local  => $SocketName,
-					    Listen => 10, 
+					    Listen => 250, 
 					    Type   => SOCK_STREAM)) {
 	die "Failed to create a lonc listner socket";
     }
@@ -1142,8 +1453,102 @@ sub SetupLoncListener {
 	      fd     => $socket);
 }
 
+#
+#   Toggle transaction logging.
+#  Implicit inputs:  
+#     LogTransactions
+#  Implicit Outputs:
+#     LogTransactions
+sub ToggleTransactionLogging {
+    print STDERR "Toggle transaction logging...\n";
+    if(!$LogTransactions) {
+	$LogTransactions = 1;
+    } else {
+	$LogTransactions = 0;
+    }
+
+
+    Log("SUCCESS", "Toggled transaction logging: $LogTransactions \n");
+}
+
+=pod 
+
+=head2 ChildStatus
+ 
+Child USR1 signal handler to report the most recent status
+into the status file.
+
+We also use this to reset the retries count in order to allow the
+client to retry connections with a previously dead server.
+=cut
+
+sub ChildStatus {
+    my $event = shift;
+    my $watcher = $event->w;
+
+    Debug(2, "Reporting child status because : ".$watcher->data);
+    my $docdir = $perlvar{'lonDocRoot'};
+    my $fh = IO::File->new(">>$docdir/lon-status/loncstatus.txt");
+    print $fh $$."\t".$RemoteHost."\t".$Status."\t".
+	$RecentLogEntry."\n";
+    #
+    #  Write out information about each of the connections:
+    #
+    if ($DebugLevel > 2) {
+	print $fh "Active connection statuses: \n";
+	my $i = 1;
+	print STDERR  "================================= Socket Status Dump:\n";
+	foreach my $item (keys %ActiveConnections) {
+	    my $Socket = $ActiveConnections{$item}->data;
+	    my $state  = $Socket->GetState();
+	    print $fh "Connection $i State: $state\n";
+	    print STDERR "---------------------- Connection $i \n";
+	    $Socket->Dump(-1);	# Ensure it gets dumped..
+	    $i++;	
+	}
+    }
+    $ConnectionRetriesLeft = $ConnectionRetries;
+}
+
 =pod
 
+=head2 SignalledToDeath
+
+Called in response to a signal that causes a chid process to die.
+
+=cut
+
+
+sub SignalledToDeath {
+    my $event  = shift;
+    my $watcher= $event->w;
+
+    Debug(2,"Signalled to death! via ".$watcher->data);
+    my ($signal) = $watcher->data;
+    chomp($signal);
+    Log("CRITICAL", "Abnormal exit.  Child $$ for $RemoteHost "
+	."died through "."\"$signal\"");
+    LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
+	    ."\"$signal\"");
+    exit 0;
+
+}
+
+=head2 ToggleDebug
+
+This sub toggles trace debugging on and off.
+
+=cut
+
+sub ToggleDebug {
+    my $Current    = $DebugLevel;
+       $DebugLevel = $NextDebugLevel;
+       $NextDebugLevel = $Current;
+
+    Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
+
+}
+
 =head2 ChildProcess
 
 This sub implements a child process for a single lonc daemon.
@@ -1152,18 +1557,26 @@ This sub implements a child process for
 
 sub ChildProcess {
 
-    print "Loncnew\n";
 
-    # For now turn off signals.
-    
-    $SIG{QUIT}  = IGNORE;
-    $SIG{HUP}   = IGNORE;
-    $SIG{USR1}  = IGNORE;
-    $SIG{INT}   = IGNORE;
-    $SIG{CHLD}  = IGNORE;
-    $SIG{__DIE__}  = IGNORE;
+    #
+    #  Signals must be handled by the Event framework...
+#
+
+    Event->signal(signal   => "QUIT",
+		  cb       => \&SignalledToDeath,
+		  data     => "QUIT");
+    Event->signal(signal   => "HUP",
+		  cb       => \&ChildStatus,
+		  data     => "HUP");
+    Event->signal(signal   => "USR1",
+		  cb       => \&ChildStatus,
+		  data     => "USR1");
+    Event->signal(signal   => "USR2",
+		  cb       => \&ToggleTransactionLogging);
+    Event->signal(signal   => "INT",
+		  cb       => \&ToggleDebug,
+		  data     => "INT");
 
-    SetupTimer();
     
     SetupLoncListener();
     
@@ -1173,12 +1586,9 @@ sub ChildProcess {
 
 # Setup the initial server connection:
     
-    &MakeLondConnection();
+     # &MakeLondConnection(); // let first work requirest do� it.
+
 
-    if($ConnectionCount == 0) {
-	Debug(1,"Could not make initial connection..\n");
-	Debug(1,"Will retry when there's work to do\n");
-    }
     Debug(9,"Entering event loop");
     my $ret = Event::loop();		#  Start the main event loop.
     
@@ -1190,15 +1600,23 @@ sub ChildProcess {
 
 sub CreateChild {
     my $host = shift;
+
+    my $sigset = POSIX::SigSet->new(SIGINT);
+    sigprocmask(SIG_BLOCK, $sigset);
     $RemoteHost = $host;
-    Debug(3, "Forking off child for ".$RemoteHost);
-    sleep(5);
-    $pid          = fork;
+    Log("CRITICAL", "Forking server for ".$host);
+    my $pid          = fork;
     if($pid) {			# Parent
-	$ChildHash{$pid} = $RemoteHost;
+	$RemoteHost = "Parent";
+	$ChildHash{$pid} = $host;
+	$HostToPid{$host}= $pid;
+	sigprocmask(SIG_UNBLOCK, $sigset);
+
     } else {			# child.
 	ShowStatus("Connected to ".$RemoteHost);
-	ChildProcess;
+	$SIG{INT} = 'DEFAULT';
+	sigprocmask(SIG_UNBLOCK, $sigset);
+	ChildProcess;		# Does not return.
     }
 
 }
@@ -1220,11 +1638,7 @@ sub CreateChild {
 
 
 
-ShowStatus("Parent writing pid file:");
-$execdir = $perlvar{'lonDaemons'};
-open (PIDSAVE, ">$execdir/logs/lonc.pid");
-print PIDSAVE "$$\n";
-close(PIDSAVE);
+
 
 ShowStatus("Forming new session");
 my $childpid = fork;
@@ -1232,6 +1646,17 @@ if ($childpid != 0) {
     sleep 4;			# Give child a chacne to break to
     exit 0;			# a new sesion.
 }
+#
+#   Write my pid into the pid file so I can be located
+#
+
+ShowStatus("Parent writing pid file:");
+my $execdir = $perlvar{'lonDaemons'};
+open (PIDSAVE, ">$execdir/logs/lonc.pid");
+print PIDSAVE "$$\n";
+close(PIDSAVE);
+
+
 
 if (POSIX::setsid() < 0) {
     print "Could not create new session\n";
@@ -1240,29 +1665,265 @@ if (POSIX::setsid() < 0) {
 
 ShowStatus("Forking node servers");
 
+Log("CRITICAL", "--------------- Starting children ---------------");
+
+LondConnection::ReadConfig;               # Read standard config files.
 my $HostIterator = LondConnection::GetHostIterator;
 while (! $HostIterator->end()) {
 
-    $hostentryref = $HostIterator->get();
+    my $hostentryref = $HostIterator->get();
     CreateChild($hostentryref->[0]);
+    $HostHash{$hostentryref->[0]} = $hostentryref->[4];
     $HostIterator->next();
 }
+$RemoteHost = "Parent Server";
 
 # Maintain the population:
 
 ShowStatus("Parent keeping the flock");
 
+#
+#   Set up parent signals:
+#
+
+$SIG{INT}  = \&Terminate;
+$SIG{TERM} = \&Terminate; 
+$SIG{HUP}  = \&Restart;
+$SIG{USR1} = \&CheckKids; 
+$SIG{USR2} = \&UpdateKids;	# LonManage update request.
+
 while(1) {
-    $deadchild = wait();
+    my $deadchild = wait();
     if(exists $ChildHash{$deadchild}) {	# need to restart.
-	$deadhost = $ChildHash{$deadchild};
+	my $deadhost = $ChildHash{$deadchild};
+	delete($HostToPid{$deadhost});
 	delete($ChildHash{$deadchild});
-	Debug(4,"Lost child pid= ".$deadchild.
+	Log("WARNING","Lost child pid= ".$deadchild.
 	      "Connected to host ".$deadhost);
+	Log("INFO", "Restarting child procesing ".$deadhost);
 	CreateChild($deadhost);
     }
 }
 
+
+
+=pod
+
+=head1 CheckKids
+
+  Since kids do not die as easily in this implementation
+as the previous one, there  is no need to restart the
+dead ones (all dead kids get restarted when they die!!)
+The only thing this function does is to pass USR1 to the
+kids so that they report their status.
+
+=cut
+
+sub CheckKids {
+    Debug(2, "Checking status of children");
+    my $docdir = $perlvar{'lonDocRoot'};
+    my $fh = IO::File->new(">$docdir/lon-status/loncstatus.txt");
+    my $now=time;
+    my $local=localtime($now);
+    print $fh "LONC status $local - parent $$ \n\n";
+    foreach my $pid (keys %ChildHash) {
+	Debug(2, "Sending USR1 -> $pid");
+	kill 'USR1' => $pid;	# Tell Child to report status.
+	sleep 1;		# Wait so file doesn't intermix.
+    }
+}
+
+=pod
+
+=head1  UpdateKids
+
+parent's SIGUSR2 handler.  This handler:
+
+=item
+
+Rereads the hosts file.
+
+=item
+ 
+Kills off (via sigint) children for hosts that have disappeared.
+
+=item
+
+QUITs  children for hosts that already exist (this just forces a status display
+and resets the connection retry count for that host.
+
+=item
+
+Starts new children for hosts that have been added to the hosts.tab file since
+the start of the master program and maintains them.
+
+=cut
+
+sub UpdateKids {
+
+    Log("INFO", "Updating connections via SIGUSR2");
+
+    #  Just in case we need to kill our own lonc, we wait a few seconds to
+    #  give it a chance to receive and relay lond's response to the 
+    #  re-init command.
+    #
+
+    sleep(2);			# Wait a couple of seconds.
+
+    my %hosts;                   # Indexed by loncapa hostname, value=ip.
+    
+    # Need to re-read  the host table:
+    
+    
+    LondConnection::ReadConfig();
+    my $I = LondConnection::GetHostIterator;
+    while (! $I->end()) {
+	my $item = $I->get();
+	$hosts{$item->[0]} = $item->[4];
+	$I->next();
+    }
+
+    #  The logic below is written for clarity not for efficiency.
+    #  Since I anticipate that this function is only rarely called, that's
+    #  appropriate.  There are certainly ways to combine the loops below,
+    #  and anyone wishing to obscure the logic is welcome to go for it.
+    #  Note that we don't re-direct sigchild.  Instead we do what's needed
+    #  to the data structures that keep track of children to ensure that
+    #  when sigchild is honored, no new child is born.
+    #
+
+    #  For each existing child; if it's host doesn't exist, kill the child.
+
+    foreach my $child (keys %ChildHash) {
+	my $oldhost = $ChildHash{$child};
+	if (!(exists $hosts{$oldhost})) {
+	    Log("CRITICAL", "Killing child for $oldhost  host no longer exists");
+	    delete $ChildHash{$child};
+	    delete $HostToPid{$oldhost};
+	    kill 'QUIT' => $child;
+	}
+    }
+    # For each remaining existing child; if it's host's ip has changed,
+    # Restart the child on the new IP.
+
+    foreach my $child (keys %ChildHash) {
+	my $oldhost = $ChildHash{$child};
+	my $oldip   = $HostHash{$oldhost};
+	if ($hosts{$oldhost} ne $oldip) {
+
+	    # kill the old child.
+
+	    Log("CRITICAL", "Killing child for $oldhost host ip has changed...");
+	    delete $ChildHash{$child};
+	    delete $HostToPid{$oldhost};
+	    kill 'QUIT' => $child;
+
+	    # Do the book-keeping needed to start a new child on the
+	    # new ip.
+
+	    $HostHash{$oldhost} = $hosts{$oldhost};
+	    CreateChild($oldhost);
+	}
+    }
+    # Finally, for each new host, not in the host hash, create a
+    # enter the host and create a new child.
+    # Force a status display of any existing process.
+
+    foreach my $host (keys %hosts) {
+	if(!(exists $HostHash{$host})) {
+	    Log("INFO", "New host $host discovered in hosts.tab...");
+	    $HostHash{$host} = $hosts{$host};
+	    CreateChild($host);
+	} else {
+	    kill 'HUP' => $HostToPid{$host};    # status display.
+	}
+    }
+}
+
+
+=pod
+
+=head1 Restart
+
+Signal handler for HUP... all children are killed and
+we self restart.  This is an el-cheapo way to re read
+the config file.
+
+=cut
+
+sub Restart {
+    &KillThemAll;		# First kill all the children.
+    Log("CRITICAL", "Restarting");
+    my $execdir = $perlvar{'lonDaemons'};
+    unlink("$execdir/logs/lonc.pid");
+    exec("$execdir/loncnew");
+}
+
+=pod
+
+=head1 KillThemAll
+
+Signal handler that kills all children by sending them a 
+SIGHUP.  Responds to sigint and sigterm.
+
+=cut
+
+sub KillThemAll {
+    Debug(2, "Kill them all!!");
+    local($SIG{CHLD}) = 'IGNORE';      # Our children >will< die.
+    foreach my $pid (keys %ChildHash) {
+	my $serving = $ChildHash{$pid};
+	ShowStatus("Nicely Killing lonc for $serving pid = $pid");
+	Log("CRITICAL", "Nicely Killing lonc for $serving pid = $pid");
+	kill 'QUIT' => $pid;
+    }
+
+
+}
+
+
+#
+#  Kill all children via KILL.  Just in case the
+#  first shot didn't get them.
+
+sub really_kill_them_all_dammit
+{
+    Debug(2, "Kill them all Dammit");
+    local($SIG{CHLD} = 'IGNORE'); # In case some purist reenabled them.
+    foreach my $pid (keys %ChildHash) {
+	my $serving = $ChildHash{$pid};
+	&ShowStatus("Nastily killing lonc for $serving pid = $pid");
+	Log("CRITICAL", "Nastily killing lonc for $serving pid = $pid");
+	kill 'KILL' => $pid;
+	delete($ChildHash{$pid});
+	my $execdir = $perlvar{'lonDaemons'};
+	unlink("$execdir/logs/lonc.pid");
+    }
+}
+=pod
+
+=head1 Terminate
+ 
+Terminate the system.
+
+=cut
+
+sub Terminate {
+    &Log("CRITICAL", "Asked to kill children.. first be nice...");
+    &KillThemAll;
+    #
+    #  By now they really should all be dead.. but just in case 
+    #  send them all SIGKILL's after a bit of waiting:
+
+    sleep(4);
+    &Log("CRITICAL", "Now kill children nasty");
+    &really_kill_them_all_dammit;
+    Log("CRITICAL","Master process exiting");
+    exit 0;
+
+}
+=pod
+
 =head1 Theory
 
 The event class is used to build this as a single process with an