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Diff for /loncom/loncnew between versions 1.2 and 1.31

-version 1.2, 2003/04/18 02:59:31
+version 1.31, 2003/10/28 10:48:10
  Line 7
  # 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.
- Line 27
+ Line 26
  # 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)
  #    - Add timer dispatch.       (done)
  #    - Add ability to accept lonc UNIX domain sockets.  (done)
  #    - Add ability to create/negotiate lond connections (done).
- #    - Add general logic for dispatching requests and timeouts.
+ #    - Add general logic for dispatching requests and timeouts. (done).
- #    - Add support for the lonc/lond requests.
+ #    - Add support for the lonc/lond requests.          (done).
  #    - Add logging/status monitoring.
  #    - Add Signal handling - HUP restarts. USR1 status report.
- #    - Add Configuration file I/O
+ #    - Add Configuration file I/O                       (done).
- #    - Add Pending request processing on startup.
  #    - Add management/status request interface.
+ #    - Add deferred request capability.                  (done)
+ #    - Detect transmission timeouts.
+ #
+ # Change log:
+ #    $Log$
+ #    Revision 1.31  2003/10/28 10:48:10  foxr
+ #    Call LondConnection::ReadConfig explicitly so that the configuration is loaded
+ #    prior to getting the hosts table hashiterator.
+ #
+ #    Revision 1.30  2003/10/27 10:09:21  foxr
+ #    Tighten up a few compares to eq and flip a few debug levels around... nothing
+ #    critical
+ #
+ #    Revision 1.29  2003/10/21 14:24:42  foxr
+ #    Fix little typo that may explain growth of connections
+ #
+ #    Revision 1.28  2003/10/14 15:36:21  albertel
+ #    - making it easier to run loncnew,
+ #       /etc/init.d/loncontrol startnew
+ #       /etc/init.d/loncontrol restartnew
+ #      will now start loncnew in place of lonc
+ #
+ #    Revision 1.27  2003/10/07 11:23:03  foxr
+ #    Installed and tested code to process reinit in parent server.
+ #
+ #    Revision 1.26  2003/09/30 11:11:17  foxr
+ #    Add book-keeping hashes to support the re-init procedure.
+ #
+ #    Revision 1.25  2003/09/23 11:22:14  foxr
+ #    Tested ability to receive sigusr2  This is now logged and must be
+ #    properly implemented as a re-read of hosts and re-init of appropriate
+ #    children.
+ #
+ #    Revision 1.24  2003/09/16 09:46:42  foxr
+ #    Added skeletal infrastructure to support SIGUSR2 update hosts request.
+ #
+ #    Revision 1.23  2003/09/15 09:24:49  foxr
+ #    Add use strict and fix all the fallout from that.
+ #
+ #    Revision 1.22  2003/09/02 10:34:47  foxr
+ #    - Fix errors in host dead detection logic (too many cases where the
+ #      retries left were not getting incremented or just not checked).
+ #    - Added some additional status to the ps axuww display:
+ #      o Remaining retries on a host.
+ #      o >>> DEAD <<< indicator if I've given up on a host.
+ #    - Tested the SIGHUP will reset the retries remaining count (thanks to
+ #      the above status stuff, and get allow the loncnew to re-try again
+ #      on the host (thanks to the log).
+ #
+ #    Revision 1.21  2003/08/26 09:19:51  foxr
+ #    How embarrassing... put in the SocketTimeout function in loncnew and forgot
+ #    to actually hook it into the LondTransaction.  Added this to MakeLondConnection
+ #    where it belongs... hopefully transactions (not just connection attempts) will
+ #    timeout more speedily than the socket errors will catch it.
+ #
+ #    Revision 1.20  2003/08/25 18:48:11  albertel
+ #    - fixing a forgotten ;
+ #
+ #    Revision 1.19  2003/08/19 09:31:46  foxr
+ #    Get socket directory from configuration rather than the old hard coded test
+ #    way that I forgot to un-hard code.
+ #
+ #    Revision 1.18  2003/08/06 09:52:29  foxr
+ #    Also needed to remember to fail in-flight transactions if their sends fail.
+ #
+ #    Revision 1.17  2003/08/03 00:44:31  foxr
+ #    1. Correct handling of connection failure: Assume it means the host is
+ #       unreachable and fail all of the queued transactions.  Note that the
+ #       inflight transactions should fail on their own time due either to timeout
+ #       or send/receive failures.
+ #    2. Correct handling of logs for forced death signals.  Pull the signal
+ #       from the event watcher.
+ #
+ #    Revision 1.16  2003/07/29 02:33:05  foxr
+ #    Add SIGINT processing to child processes to toggle annoying trace mode
+ #    on/off.. will try to use this to isolate the compute boud process issue.
+ #
+ #    Revision 1.15  2003/07/15 02:07:05  foxr
+ #    Added code for lonc/lond transaction timeouts.  Who knows if it works right.
+ #    The intent is for a timeout to fail any transaction in progress and kill
+ #    off the sockt that timed out.
+ #
+ #    Revision 1.14  2003/07/03 02:10:18  foxr
+ #    Get all of the signals to work correctly.
+ #
+ #    Revision 1.13  2003/07/02 01:31:55  foxr
+ #    Added kill -HUP logic (restart).
+ #
+ #    Revision 1.11  2003/06/25 01:54:44  foxr
+ #    Fix more problems with transaction failure.
+ #
+ #    Revision 1.10  2003/06/24 02:46:04  foxr
+ #    Put a limit on  the number of times we'll retry a connection.
+ #    Start getting the signal stuff put in as well...note that need to get signals
+ #    going or else the client will permanently give up on dead servers.
+ #
+ #    Revision 1.9  2003/06/13 02:38:43  foxr
+ #    Add logging in 'expected format'
+ #
+ #    Revision 1.8  2003/06/11 02:04:35  foxr
+ #    Support delayed transactions... this is done uniformly by encapsulating
+ #    transactions in an object ... a LondTransaction that is implemented by
+ #    LondTransaction.pm
+ #
+ #    Revision 1.7  2003/06/03 01:59:39  foxr
+ #    complete coding to support deferred transactions.
+ #
+ #
+ 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;
  use LONCAPA::Queue;
  use LONCAPA::Stack;
  use LONCAPA::LondConnection;
+ 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;
- $SIG{__DIE__}  = IGNORE;
  # Read the httpd configuration file to get perl variables
- Line 80  my %perlvar    = %{$perlvarref};
+ Line 184  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 $DebugLevel = 0;
+ my $NextDebugLevel= 2;		# So Sigint can toggle this.
  my $IdleTimeout= 3600;		# Wait an hour before pruning connections.
  #
  #  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;		# Transactions in flight.
+ 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.
  #
+ #   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 ";
  =pod
- =head 2 GetPeerName
-    Returns the name of the host that a socket object is connected
+ =head2 LogPerm
-    to.
+ 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 = shift;
+     my $message  = shift;
+     if(!$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
+ =head2 GetPeerName
+ Returns the name of the host that a socket object is connected to.
  =cut
  sub GetPeername {
- Line 117  sub GetPeername {
+ Line 308  sub GetPeername {
      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;
- Line 127  sub GetPeername {
+ Line 318  sub GetPeername {
  }
  #----------------------------- Timer management ------------------------
  =pod
  =head2 Debug
-    Invoked to issue a debug message.
+ Invoked to issue a debug message.
  =cut
  sub Debug {
      my $level   = shift;
      my $message = shift;
      if ($level <= $DebugLevel) {
- 	print $message." host = ".$RemoteHost."\n";
+ 	Log("INFO", "-Debug- $message host = $RemoteHost");
      }
  }
- Line 145  sub SocketDump {
+ Line 340  sub SocketDump {
  	$socket->Dump();
      }
  }
+ =pod
+ =head2 ShowStatus
+  Place some text as our pid status.
+  and as what we return in a SIGUSR1
+ =cut
+ sub ShowStatus {
+     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;
+     KillSocket($Socket);	# A transaction timeout also counts as
+                                 # a connection failure:
+     $ConnectionRetriesLeft--;
+ }
+ =pod
  =head2 Tick
-     Invoked  each timer tick.
+ Invoked  each timer tick.
  =cut
  sub Tick {
      my $client;
-     Debug(6, "Tick");
+     if($ConnectionRetriesLeft > 0) {
-     Debug(6, "    Current connection count: ".$ConnectionCount);
+ 	ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
-     foreach $client (keys %ActiveClients) {
+ 		   ." Retries remaining: ".$ConnectionRetriesLeft);
- 	Debug(7, "    Have client:  with id: ".$ActiveClients{$client});
+     } else {
+ 	ShowStatus(GetServerHost()." >> DEAD <<");
+     }
+     # Is it time to prune connection count:
+     if($IdleConnections->Count()  &&
+        ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
+ 	$IdleSeconds++;
+ 	if($IdleSeconds > $IdleTimeout) { # Prune a connection...
+ 	    my $Socket = $IdleConnections->pop();
+ 	    KillSocket($Socket);
+ 	}
+     } else {
+ 	$IdleSeconds = 0;	# Reset idle count if not idle.
+     }
+     #
+     #  For each inflight transaction, tick down its timeout counter.
+     #
+     foreach my $item (keys %ActiveTransactions) {
+ 	my $Socket = $ActiveTransactions{$item}->getServer();
+ 	$Socket->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.
+     #
+     my $Requests = $WorkQueue->Count();
+     if (($ConnectionCount == 0)  && ($Requests > 0)) {
+ 	if ($ConnectionRetriesLeft > 0) {
+ 	    my $Connections = ($Requests <= $MaxConnectionCount) ?
+ 		$Requests : $MaxConnectionCount;
+ 	    Debug(5,"Work but no connections, start ".$Connections." of them");
+ 	    my $successCount = 0;
+ 	    for (my $i =0; $i < $Connections; $i++) {
+ 		$successCount += MakeLondConnection();
+ 	    }
+ 	    if($successCount == 0) { # All connections failed:
+ 		Debug(5,"Work in queue failed to make any connectiouns\n");
+ 		EmptyQueue();	# Fail pending transactions with con_lost.
+ 	    }
+ 	} else {
+ 	    ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
+ 	    Debug(5,"Work in queue, but gave up on connections..flushing\n");
+ 	    EmptyQueue();	# Connections can't be established.
+ 	}
      }
  }
  =pod
  =head2 SetupTimer
-    Sets up a 1 per sec recurring timer event.  The event handler is used to:
- =item Trigger timeouts on communications along active sockets.
+ Sets up a 1 per sec recurring timer event.  The event handler is used to:
- =item Trigger disconnections of idle sockets.
+ =item
+ Trigger timeouts on communications along active sockets.
+ =item
+ Trigger disconnections of idle sockets.
  =cut
- Line 173  sub SetupTimer {
+ Line 458  sub SetupTimer {
      Debug(6, "SetupTimer");
      Event->timer(interval => 1, debug => 1, cb => \&Tick );
  }
  =pod
  =head2 ServerToIdle
-    This function is called when a connection to the server is
- ready for more work.
+ This function is called when a connection to the server is
-    If there is work in the Work queue the top element is dequeued
+ ready for more work.
+ If there is work in the Work queue the top element is dequeued
  and the connection will start to work on it.  If the work queue is
  empty, the connection is pushed on the idle connection stack where
  it will either get another work unit, or alternatively, if it sits there
  long enough, it will be shut down and released.
  =cut
  sub ServerToIdle {
      my $Socket   = shift;	# Get the socket.
+     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();
+     my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
-     Debug(9, "Queue gave request data: ".$reqdata);
+     if ($reqdata ne undef)  {
-     unless($reqdata eq undef)  {
+ 	Debug(5, "Queue gave request data: ".$reqdata->getRequest());
- 	my $unixSocket = $ClientQueue->dequeue();
+ 	&StartRequest($Socket,  $reqdata);
- 	&Debug(6, "Starting new work request");
- 	&Debug(7, "Request: ".$reqdata);
- 	&StartRequest($Socket, $unixSocket, $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");
- 	delete($ActiveTransactions{$Socket});
  	$IdleConnections->push($Socket);
      }
  }
  =pod
  =head2 ClientWritable
-   Event callback for when a client socket is writable.
-   This callback is established when a transaction reponse is
+ Event callback for when a client socket is writable.
-   avaiable from lond.  The response is forwarded to the unix socket
-   as it becomes writable in this sub.
+ This callback is established when a transaction reponse is
+ avaiable from lond.  The response is forwarded to the unix socket
+ as it becomes writable in this sub.
  Parameters:
- =item Event - The event that has been triggered. Event->w->data is
+ =item Event
-               the data and Event->w->fd is the socket to write.
+ The event that has been triggered. Event->w->data is
+ the data and Event->w->fd is the socket to write.
  =cut
  sub ClientWritable {
      my $Event    = shift;
      my $Watcher  = $Event->w;
- Line 231  sub ClientWritable {
+ Line 525  sub ClientWritable {
      &Debug(6, "ClientWritable writing".$Data);
      &Debug(9, "Socket is: ".$Socket);
-     my $result = $Socket->send($Data, 0);
+     if($Socket->connected) {
+ 	my $result = $Socket->send($Data, 0);
-     # $result undefined: the write failed.
-     # otherwise $result is the number of bytes written.
-     # Remove that preceding string from the data.
-     # If the resulting data is empty, destroy the watcher
-     # and set up a read event handler to accept the next
-     # request.
-     &Debug(9,"Send result is ".$result." Defined: ".defined($result));
-     if(defined($result)) {
- 	&Debug(9, "send result was defined");
- 	if($result == length($Data)) { # Entire string sent.
- 	    &Debug(9, "ClientWritable data all written");
- 	    $Watcher->cancel();
- 	    #
- 	    #  Set up to read next request from socket:
- 	    my $descr     = sprintf("Connection to lonc client %d",
- 				    $ActiveClients{$Socket});
- 	    Event->io(cb    => \&ClientRequest,
- 		      poll  => 'r',
- 		      desc  => $descr,
- 		      data  => "",
- 		      fd    => $Socket);
- 	} else {		# Partial string sent.
- 	    $Watcher->data(substr($Data, $result));
- 	}
-     } else {			# Error of some sort...
+ 	# $result undefined: the write failed.
+ 	# otherwise $result is the number of bytes written.
- 	# Some errnos are possible:
+ 	# Remove that preceding string from the data.
- 	my $errno = $!;
+ 	# If the resulting data is empty, destroy the watcher
- 	if($errno == POSIX::EWOULDBLOCK   ||
+ 	# and set up a read event handler to accept the next
- 	   $errno == POSIX::EAGAIN        ||
+ 	# request.
- 	   $errno == POSIX::EINTR) {
- 	    # No action taken?
- 	} else {		# Unanticipated errno.
- 	    &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
- 	    $Watcher->cancel;	# Stop the watcher.
- 	    $Socket->shutdown(2); # Kill connection
- 	    $Socket->close();	# Close the socket.
- 	}
+ 	&Debug(9,"Send result is ".$result." Defined: ".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");
+ 		$Watcher->cancel();
+ 		#
+ 		#  Set up to read next request from socket:
+ 		my $descr     = sprintf("Connection to lonc client %d",
+ 					$ActiveClients{$Socket});
+ 		Event->io(cb    => \&ClientRequest,
+ 			  poll  => 'r',
+ 			  desc  => $descr,
+ 			  data  => "",
+ 			  fd    => $Socket);
+ 	    } 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...
+ 	    # Some errnos are possible:
+ 	    my $errno = $!;
+ 	    if($errno == POSIX::EWOULDBLOCK   ||
+ 	       $errno == POSIX::EAGAIN        ||
+ 	       $errno == POSIX::EINTR) {
+ 		# No action taken?
+ 	    } else {		# Unanticipated errno.
+ 		&Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
+ 		$Watcher->cancel;	# Stop the watcher.
+ 		$Socket->shutdown(2); # Kill connection
+ 		$Socket->close();	# Close the socket.
+ 	    }
+ 	}
+     } else {
+ 	$Watcher->cancel();	# A delayed request...just cancel.
      }
  }
  =pod
  =head2 CompleteTransaction
-   Called when the reply data has been received for a lond
+ Called when the reply data has been received for a lond
  transaction.   The reply data must now be sent to the
  ultimate client on the other end of the Unix socket.  This is
  done by setting up a writable event for the socket with the
  data the reply data.
  Parameters:
- =item Socket - Socket on which the lond transaction occured.  This
-       is a LondConnection. The data received is in the
+ =item Socket
- 	TransactionReply member.
- =item Client - Unix domain socket open on the ultimate client.
+ Socket on which the lond transaction occured.  This is a
+ LondConnection. The data received is in the TransactionReply member.
+ =item Transaction
+ The transaction that is being completed.
  =cut
  sub CompleteTransaction {
-     &Debug(6,"Complete transaction");
+     &Debug(5,"Complete transaction");
      my $Socket = shift;
-     my $Client = shift;
+     my $Transaction = shift;
+     if (!$Transaction->isDeferred()) { # Normal transaction
+ 	my $data   = $Socket->GetReply(); # Data to send.
+ 	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.
+ =head2  parameters:
+ =item Transaction
-     my $data   = $Socket->GetReply(); # Data to send.
+     The transaction for which we are responding to the client.
+ =item data
+     The data to send to apached client.
+ =cut
+ sub StartClientReply {
+     my $Transaction   = shift;
+     my $data     = shift;
+     my $Client   = $Transaction->getClient();
      &Debug(8," Reply was: ".$data);
      my $Serial         = $ActiveClients{$Client};
- Line 310  sub CompleteTransaction {
+ Line 653  sub CompleteTransaction {
  	      cb       => \&ClientWritable,
  	      data     => $data);
  }
+ =pod
+ =head2 FailTransaction
+   Finishes a transaction with failure because the associated lond socket
+   disconnected.  There are two possibilities:
+   - The transaction is deferred: in which case we just quietly
+     delete the transaction since there is no client connection.
+   - 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.
+ Parameters:
+ =item client
+    The LondTransaction we are failing.
+ =cut
+ sub FailTransaction {
+     my $transaction = shift;
+     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");
+     }
+     if($ConnectionRetriesLeft <= 0) {
+ 	Log("CRITICAL", "Host marked dead: ".GetServerHost());
+     }
+ }
+ =pod
+ =head1  EmptyQueue
+   Fails all items in the work queue with con_lost.
+   Note that each item in the work queue is a transaction.
+ =cut
+ sub EmptyQueue {
+     $ConnectionRetriesLeft--;	# Counts as connection failure too.
+     while($WorkQueue->Count()) {
+ 	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) {
+ 	KillSocket($Socket);
+     }
+ }
+ =cut
+ =pod
+ =head2 KillSocket
+ Destroys a socket.  This function can be called either when a socket
+ has died of 'natural' causes or because a socket needs to be pruned due to
+ idleness.  If the socket has died naturally, if there are no longer any
+ live connections a new connection is created (in case there are transactions
+ in the queue).  If the socket has been pruned, it is never re-created.
+ Parameters:
+ =item Socket
+   The socket to kill off.
+ =item Restart
+ nonzero if we are allowed to create a new connection.
+ =cut
+ 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!!!
+     #  otherwise it came from the idle set.
+     #
+     if(exists($ActiveTransactions{$Socket})) {
+ 	delete ($ActiveTransactions{$Socket});
+     }
+     if(exists($ActiveConnections{$Socket})) {
+ 	delete($ActiveConnections{$Socket});
+     }
+     $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();
+     }
+ }
  =pod
  =head2 LondReadable
  This function is called whenever a lond connection
  is readable.  The action is state dependent:
- =head3 State = Initialized
+ =head3 State=Initialized
-     We''re waiting for the challenge, this is a no-op until the
+ We''re waiting for the challenge, this is a no-op until the
  state changes.
  =head3 State=Challenged
-     The challenge has arrived we need to transition to Writable.
+ The challenge has arrived we need to transition to Writable.
  The connection must echo the challenge back.
  =head3 State=ChallengeReplied
-     The challenge has been replied to.  The we are receiveing the
+ The challenge has been replied to.  The we are receiveing the
  'ok' from the partner.
  =head3 State=RequestingKey
-     The ok has been received and we need to send the request for
+ The ok has been received and we need to send the request for
  an encryption key.  Transition to writable for that.
  =head3 State=ReceivingKey
-     The the key has been requested, now we are reading the new key.
+ The the key has been requested, now we are reading the new key.
  =head3 State=Idle
-     The encryption key has been negotiated or we have finished
+ The encryption key has been negotiated or we have finished
  reading data from the a transaction.   If the callback data has
  a client as well as the socket iformation, then we are
  doing a transaction and the data received is relayed to the client
  before the socket is put on the idle list.
  =head3 State=SendingRequest
-     I do not think this state can be received here, but if it is,
+ I do not think this state can be received here, but if it is,
  the appropriate thing to do is to transition to writable, and send
  the request.
  =head3 State=ReceivingReply
-     We finished sending the request to the server and now transition
+ We finished sending the request to the server and now transition
  to readable to receive the reply.
  The parameter to this function are:
  The event. Implicit in this is the watcher and its data.  The data
  contains at least the lond connection object and, if a
  transaction is in progress, the socket attached to the local client.
  =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();
-     if($Socket->Readable() != 0) {
+     &Debug(2, "Socket->Readable returned: $status");
- 	 # bad return from socket read.
+     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})) {
+ 	    FailTransaction($ActiveTransactions{$Socket});
+ 	}
+ 	$Watcher->cancel();
+ 	KillSocket($Socket);
+ 	$ConnectionRetriesLeft--;       # Counts as connection failure
+ 	return;
      }
      SocketDump(6,$Socket);
- Line 380  sub LondReadable {
+ Line 870  sub LondReadable {
  	# 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") {
- Line 390  sub LondReadable {
+ Line 880  sub LondReadable {
  	#  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") {
  	# 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.
      } elsif ($State eq "SendingRequest") {
  	#  We need to be writable for this and probably don't belong
  	#  here inthe first place.
- Line 422  sub LondReadable {
+ Line 919  sub LondReadable {
  	Debug(4, "Invalid state in LondReadable");
      }
  }
  =pod
  =head2 LondWritable
  This function is called whenever a lond connection
  becomes writable while there is a writeable monitoring
  event.  The action taken is very state dependent:
  =head3 State = Connected
-   The connection is in the process of sending the
-   'init' hailing to the lond on the remote end.
+ The connection is in the process of sending the 'init' hailing to the
-    The connection object''s Writable member is called.
+ lond on the remote end.  The connection object''s Writable member is
-    On error, ConnectionError is called to destroy
+ called.  On error, ConnectionError is called to destroy the connection
-    the connection and remove it from the ActiveConnections
+ and remove it from the ActiveConnections hash
-    hash
  =head3 Initialized
-    'init' has been sent, writability monitoring is
-     removed and readability monitoring is started
+ 'init' has been sent, writability monitoring is removed and
-     with LondReadable as the callback.
+ readability monitoring is started with LondReadable as the callback.
  =head3 ChallengeReceived
-     The connection has received the who are you
-    challenge from the remote system, and is in the
+ The connection has received the who are you challenge from the remote
-     process of sending the challenge response.
+ system, and is in the process of sending the challenge
-     Writable is called.
+ response. Writable is called.
  =head3 ChallengeReplied
-     The connection has replied to the initial challenge
-     The we switch to monitoring readability looking
+ The connection has replied to the initial challenge The we switch to
-     for the server to reply with 'ok'.
+ monitoring readability looking for the server to reply with 'ok'.
  =head3 RequestingKey
-     The connection is in the process of requesting its
-     encryption key.  Writable is called.
+ The connection is in the process of requesting its encryption key.
+ Writable is called.
  =head3 ReceivingKey
-     The connection has sent the request for a key.
-     Switch to readability monitoring to accept the key
+ The connection has sent the request for a key.  Switch to readability
+ monitoring to accept the key
  =head3 SendingRequest
-     The connection is in the process of sending a
-     request to the server.  This request is part of
+ The connection is in the process of sending a request to the server.
-     a client transaction.  All the states until now
+ This request is part of a client transaction.  All the states until
-     represent the client setup protocol. Writable
+ now represent the client setup protocol. Writable is called.
-     is called.
  =head3 ReceivingReply
-     The connection has sent a request.  Now it must
-     receive a reply.  Readability monitoring is
-     requested.
-  This function is an event handler and therefore receives as
+ The connection has sent a request.  Now it must receive a reply.
+ Readability monitoring is requested.
+ This function is an event handler and therefore receives as
  a parameter the event that has fired.  The data for the watcher
  of this event is a reference to a list of one or two elements,
  depending on state. The first (and possibly only) element is the
- Line 472  socket.  The second (present only if a r
+ Line 980  socket.  The second (present only if a r
  is the socket on which to return a reply to the caller.
  =cut
  sub LondWritable {
      my $Event   = shift;
      my $Watcher = $Event->w;
-     my @data    = $Watcher->data;
+     my $Socket  = $Watcher->data;
-     Debug(6,"LondWritable State = ".$State." data has ".@data." elts.\n");
+     my $State   = $Socket->GetState();
-     my $Socket  = $data[0];	# 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")         {
- 	#  "init" is being sent...
  	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");
+ 	    FailTransaction($ActiveTransactions{$Socket});
+ 	    $Watcher->cancel();
+ 	    KillSocket($Socket);
+ 	    return;
  	}
+ 	#  "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
- Line 509  sub LondWritable {
+ Line 1026  sub LondWritable {
  	# we're waiting for the state to change
  	if($Socket->Writable() != 0) {
- 	    # Write of the next chunk resulted in an error.
+ 	    $Watcher->cancel();
+ 	    KillSocket($Socket);
+ 	    return;
  	}
      } elsif ($State eq "ChallengeReplied")  {
  	# The echo was sent back, so we switch
  	# to watching readability.
- 	$Watcher->poll("r");
  	$Watcher->cb(\&LondReadable);
+ 	$Watcher->poll("r");
      } elsif ($State eq "RequestingKey")     {
  	# At this time we're requesting the key.
- Line 527  sub LondWritable {
+ Line 1047  sub LondWritable {
  	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) {
- 	    # Write resulted in an error.
+ 	    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:
- Line 562  sub LondWritable {
+ Line 1093  sub LondWritable {
      }
  }
+ =pod
+ =cut
+ sub QueueDelayed {
+     Debug(3,"QueueDelayed called");
+     my $path = "$perlvar{'lonSockDir'}/delayed";
+     Debug(4, "Delayed path: ".$path);
+     opendir(DIRHANDLE, $path);
+     my @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
+     closedir(DIRHANDLE);
+     my $dfname;
+     my $reqfile;
+     foreach $dfname (sort  @alldelayed) {
+ 	$reqfile = "$path/$dfname";
+ 	Debug(4, "queueing ".$reqfile);
+ 	my $Handle = IO::File->new($reqfile);
+ 	my $cmd    = <$Handle>;
+ 	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);
+     }
+ }
  =pod
  =head2 MakeLondConnection
-     Create a new lond connection object, and start it towards
-     its initial idleness.  Once idle, it becomes elligible to
+ Create a new lond connection object, and start it towards its initial
-     receive transactions from the work queue.  If the work queue
+ idleness.  Once idle, it becomes elligible to receive transactions
-     is not empty when the connection is completed and becomes idle,
+ from the work queue.  If the work queue is not empty when the
-     it will dequeue an entry and start off on it.
+ connection is completed and becomes idle, it will dequeue an entry and
+ start off on it.
  =cut
  sub MakeLondConnection {
      Debug(4,"MakeLondConnection to ".GetServerHost()." on port "
  	  .GetServerPort());
- Line 578  sub MakeLondConnection {
+ Line 1141  sub MakeLondConnection {
      my $Connection = LondConnection->new(&GetServerHost(),
  					 &GetServerPort());
-     if($Connection == undef) {	# Needs to be more robust later.
+     if($Connection eq undef) {	# Needs to be more robust later.
- 	die "Failed to make a connection!!".$!."\n";
+ 	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 eq undef) {
+ 	    die "did not get a socket from the connection";
+ 	} else {
+ 	    &Debug(9,"MakeLondConnection got socket: ".$Socket);
+ 	}
-     }
+ 	$Connection->SetTimeoutCallback(\&SocketTimeout);
-     # 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) {
- 	die "did not get a socket from the connection";
-     } else {
- 	&Debug(9,"MakeLondConnection got socket: ".$Socket);
-     }
+ 	my $event = Event->io(fd       => $Socket,
-     $event = Event->io(fd       => $Socket,
+ 			   poll     => 'w',
- 		       poll     => 'w',
+ 			   cb       => \&LondWritable,
- 		       cb       => \&LondWritable,
+ 			   data     => $Connection,
- 		       data     => ($Connection, undef),
+ 			   desc => 'Connection to lond server');
- 		       desc => 'Connection to lond server');
+ 	$ActiveConnections{$Connection} = $event;
-     $ActiveConnections{$Lond} = $event;
+ 	$ConnectionCount++;
-     $ConnectionCount++;
+ 	Debug(4, "Connection count = ".$ConnectionCount);
+ 	if($ConnectionCount == 1) { # First Connection:
+ 	    QueueDelayed;
+ 	}
+ 	Log("SUCESS", "Created connection ".$ConnectionCount
+ 	    ." to host ".GetServerHost());
+ 	return 1;		# Return success.
+     }
  }
  =pod
  =head2 StartRequest
-    Starts a lond request going on a specified lond connection.
-     parameters are:
+ Starts a lond request going on a specified lond connection.
- =item $Lond - Connection to the lond that will send the transaction
+ parameters are:
-     and receive the reply.
- =item $Client - Connection to the client that is making this request
+ =item $Lond
-     We got the request from this socket, and when the request has
-     been relayed to lond and we get a reply back from lond it will
+ Connection to the lond that will send the transaction and receive the
-     get sent to this socket.
+ reply.
- =item $Request - The text of the request to send.
+ =item $Client
+ Connection to the client that is making this request We got the
+ request from this socket, and when the request has been relayed to
+ lond and we get a reply back from lond it will get sent to this
+ socket.
+ =item $Request
+ The text of the request to send.
  =cut
  sub StartRequest {
      my $Lond     = shift;
-     my $Client   = shift;
+     my $Request  = shift;	# This is a LondTransaction.
-     my $Request  = shift;
-     Debug(6, "StartRequest: ".$Request);
+     Debug(6, "StartRequest: ".$Request->getRequest());
      my $Socket = $Lond->GetSocket();
-     $ActiveTransactions{$Lond} = $Client; # Socket to relay to client.
+     $Request->Activate($Lond);
+     $ActiveTransactions{$Lond} = $Request;
-     $Lond->InitiateTransaction($Request);
+     $Lond->InitiateTransaction($Request->getRequest());
-     $event = Event->io(fd      => $Lond->GetSocket(),
+     my $event = Event->io(fd      => $Socket,
  		       poll    => "w",
  		       cb      => \&LondWritable,
  		       data    => $Lond,
- Line 641  sub StartRequest {
+ Line 1227  sub StartRequest {
  }
  =pod
  =head2 QueueTransaction
-     - If there is an idle lond connection, it is put to
-     work doing this transaction.  Otherwise, the transaction is
+ If there is an idle lond connection, it is put to work doing this
-     placed in the work queue.  If placed in the work queue and the
+ transaction.  Otherwise, the transaction is placed in the work queue.
-     maximum number of connections has not yet been created, a new
+ If placed in the work queue and the maximum number of connections has
-     connection will be started.  Our goal is to eventually have
+ not yet been created, a new connection will be started.  Our goal is
-     a sufficient number of connections that the work queue will
+ to eventually have a sufficient number of connections that the work
-     typically be empty.
+ queue will typically be empty.  parameters are:
-     parameters are:
- =item Socket open on the lonc client.
+ =item Socket
- =item Request data to send to the lond.
+ open on the lonc client.
+ =item Request
+ data to send to the lond.
  =cut
  sub QueueTransaction {
-     my $requestSocket = shift;
-     my $requestData   = shift;
-     Debug(6,"QueueTransaction: ".$requestData);
+     my $requestData   = shift;	# This is a LondTransaction.
+     my $cmd           = $requestData->getRequest();
+     Debug(6,"QueueTransaction: ".$cmd);
      my $LondSocket    = $IdleConnections->pop();
      if(!defined $LondSocket) {	# Need to queue request.
- 	Debug(8,"Must queue...");
+ 	Debug(5,"Must queue...");
- 	$ClientQueue->enqueue($requestSocket);
  	$WorkQueue->enqueue($requestData);
  	if($ConnectionCount < $MaxConnectionCount) {
- 	    Debug(4,"Starting additional lond connection");
+ 	    if($ConnectionRetriesLeft > 0) {
- 	    MakeLondConnection();
+ 		Debug(5,"Starting additional lond connection");
+ 		if(MakeLondConnection() == 0) {
+ 		    EmptyQueue();	# Fail transactions, can't make connection.
+ 		}
+ 	    } else {
+ 		ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
+ 		EmptyQueue();	# It's worse than that ... he's dead Jim.
+ 	    }
  	}
      } else {			# Can start the request:
  	Debug(8,"Can start...");
- 	StartRequest($LondSocket, $requestSocket, $requestData);
+ 	StartRequest($LondSocket,  $requestData);
      }
  }
  #-------------------------- Lonc UNIX socket handling ---------------------
  =pod
  =head2 ClientRequest
-    Callback that is called when data can be read from the
+ Callback that is called when data can be read from the UNIX domain
-    UNIX domain socket connecting us with an apache server process.
+ socket connecting us with an apache server process.
  =cut
- Line 696  sub ClientRequest {
+ Line 1298  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 eq "close_connection_exit\n") {
+ 	    Log("CRITICAL",
+ 		"Request Close Connection ... exiting");
+ 	    CloseAllLondConnections();
+ 	    exit;
+ 	}
  	Debug(8, "Complete transaction received: ".$data);
- 	QueueTransaction($socket, $data);
+ 	my $Transaction = LondTransaction->new($data);
+ 	$Transaction->SetClient($socket);
+ 	QueueTransaction($Transaction);
  	$watcher->cancel();	# Done looking for input data.
      }
- Line 716  sub ClientRequest {
+ Line 1327  sub ClientRequest {
  =pod
  =head2  NewClient
-     Callback that is called when a connection is received on the
-     unix socket for a new client of lonc.  The callback is parameterized
+ Callback that is called when a connection is received on the unix
-     by the event.. which is a-priori assumed to be an  io event, and therefore
+ socket for a new client of lonc.  The callback is parameterized by the
-     has an fd member that is the Listener socket.   We Accept the connection
+ event.. which is a-priori assumed to be an io event, and therefore has
-     and register a new event on the readability of that socket:
+ an fd member that is the Listener socket.  We Accept the connection
+ and register a new event on the readability of that socket:
  =cut
  sub NewClient {
      Debug(6, "NewClient");
      my $event      = shift;		# Get the event parameters.
- Line 744  sub NewClient {
+ Line 1359  sub NewClient {
      $ActiveClients{$connection} = $ClientConnection;
      $ClientConnection++;
  }
- =pod GetLoncSocketPath
-     Returns the name of the UNIX socket on which to listen for client
+ =pod
-     connections.
+ =head2 GetLoncSocketPath
+ Returns the name of the UNIX socket on which to listen for client
+ connections.
  =cut
  sub GetLoncSocketPath {
      return $UnixSocketDir."/".GetServerHost();
  }
- =pod GetServerHost
+ =pod
-    Returns the host whose lond we talk with.
+ =head2 GetServerHost
+ Returns the host whose lond we talk with.
  =cut
- sub GetServerHost {		# Stub - get this from config.
+ sub GetServerHost {
      return $RemoteHost;		# Setup by the fork.
  }
- =pod GetServerPort
-    Returns the lond port number.
+ =pod
+ =head2 GetServerPort
+ Returns the lond port number.
  =cut
- sub GetServerPort {		# Stub - get this from config.
+ sub GetServerPort {
      return $perlvar{londPort};
  }
- =pod SetupLoncListener
-    Setup a lonc listener event.  The event is called when
+ =pod
-    the socket becomes readable.. that corresponds to the
-    receipt of a new connection.  The event handler established
+ =head2 SetupLoncListener
-    will accept the connection (creating a communcations channel), that
-    int turn will establish another event handler to subess requests.
+ Setup a lonc listener event.  The event is called when the socket
+ becomes readable.. that corresponds to the receipt of a new
+ connection.  The event handler established will accept the connection
+ (creating a communcations channel), that int turn will establish
+ another event handler to subess requests.
  =cut
  sub SetupLoncListener {
      my $socket;
      my $SocketName = GetLoncSocketPath();
      unlink($SocketName);
-     unless ($socket = IO::Socket::UNIX->new(Local  => $SocketName,
+     unless ($socket =IO::Socket::UNIX->new(Local  => $SocketName,
  					    Listen => 10,
  					    Type   => SOCK_STREAM)) {
  	die "Failed to create a lonc listner socket";
- Line 789  sub SetupLoncListener {
+ Line 1425  sub SetupLoncListener {
  	      fd     => $socket);
  }
+ =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";
+     $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.
- Line 798  This sub implements a child process for
+ Line 1494  This sub implements a child process for
  sub ChildProcess {
-     print "Loncnew\n";
-     # For now turn off signals.
+     #
+     #  Signals must be handled by the Event framework...
-     $SIG{QUIT}  = IGNORE;
+ #
-     $SIG{HUP}   = IGNORE;
-     $SIG{USR1}  = IGNORE;
+     Event->signal(signal   => "QUIT",
-     $SIG{INT}   = IGNORE;
+ 		  cb       => \&SignalledToDeath,
-     $SIG{CHLD}  = IGNORE;
+ 		  data     => "QUIT");
-     $SIG{__DIE__}  = IGNORE;
+     Event->signal(signal   => "HUP",
+ 		  cb       => \&ChildStatus,
+ 		  data     => "HUP");
+     Event->signal(signal   => "USR1",
+ 		  cb       => \&ChildStatus,
+ 		  data     => "USR1");
+     Event->signal(signal   => "INT",
+ 		  cb       => \&ToggleDebug,
+ 		  data     => "INT");
      SetupTimer();
- Line 819  sub ChildProcess {
+ Line 1522  sub ChildProcess {
  # Setup the initial server connection:
-     &MakeLondConnection();
+      # &MakeLondConnection(); // let first work requirest do it.
      Debug(9,"Entering event loop");
      my $ret = Event::loop();		#  Start the main event loop.
- Line 831  sub ChildProcess {
+ Line 1535  sub ChildProcess {
  #  Create a new child for host passed in:
  sub CreateChild {
+     my $sigset = POSIX::SigSet->new(SIGINT);
+     sigprocmask(SIG_BLOCK, $sigset);
      my $host = shift;
      $RemoteHost = $host;
-     Debug(3, "Forking off child for ".$RemoteHost);
+     Log("CRITICAL", "Forking server for ".$host);
-     sleep(5);
+     my $pid          = fork;
-     $pid          = fork;
      if($pid) {			# Parent
- 	$ChildHash{$pid} = $RemoteHost;
+ 	$RemoteHost = "Parent";
+ 	$ChildHash{$pid} = $host;
+ 	$HostToPid{$host}= $pid;
+ 	sigprocmask(SIG_UNBLOCK, $sigset);
      } else {			# child.
- 	ChildProcess;
+ 	ShowStatus("Connected to ".$RemoteHost);
+ 	$SIG{INT} = 'DEFAULT';
+ 	sigprocmask(SIG_UNBLOCK, $sigset);
+ 	ChildProcess;		# Does not return.
      }
  }
- Line 853  sub CreateChild {
+ Line 1565  sub CreateChild {
  #  Each exit gets logged and the child gets restarted.
  #
+ #
+ #   Fork and start in new session so hang-up isn't going to
+ #   happen without intent.
+ #
+ ShowStatus("Forming new session");
+ my $childpid = fork;
+ if ($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";
+     exit -1;
+ }
+ 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};
+ 	Debug(2, "Killing lonc for $serving pid = $pid");
+ 	ShowStatus("Killing lonc for $serving pid = $pid");
+ 	Log("CRITICAL", "Killing lonc for $serving pid = $pid");
+ 	kill 'QUIT' => $pid;
+ 	delete($ChildHash{$pid});
+     }
+     my $execdir = $perlvar{'lonDaemons'};
+     unlink("$execdir/logs/lonc.pid");
+ }
+ =pod
+ =head1 Terminate
+ Terminate the system.
+ =cut
+ sub Terminate {
+     KillThemAll;
+     Log("CRITICAL","Master process exiting");
+     exit 0;
+ }
+ =pod
  =head1 Theory
-    The event class is used to build this as a single process with
-    an event driven model.  The following events are handled:
+ The event class is used to build this as a single process with an
+ event driven model.  The following events are handled:
  =item UNIX Socket connection Received
- Line 890  All sockets are run in non-blocking mode
+ Line 1852  All sockets are run in non-blocking mode
  handler prevents hung connections.
  Key data structures:
- =item RequestQueue - A queue of requests received from UNIX sockets that are
-     waiting for a chance to be forwarded on a lond connection socket.
- =item ActiveConnections - A hash of lond connections that have transactions
+ =item RequestQueue
-     in process that are available to be timed out.
+ A queue of requests received from UNIX sockets that are
+ waiting for a chance to be forwarded on a lond connection socket.
+ =item ActiveConnections
+ A hash of lond connections that have transactions in process that are
+ available to be timed out.
+ =item ActiveTransactions
+ A hash indexed by lond connections that contain the client reply
+ socket for each connection that has an active transaction on it.
+ =item IdleConnections
+ A hash of lond connections that have no work to do.  These connections
+ can be closed if they are idle for a long enough time.
- =item ActiveTransactions - A hash indexed by lond connections that
-     contain the client reply socket for each connection that has an active
-     transaction on it.
- =item IdleConnections - A hash of lond connections that have no work
-     to do.  These connections can be closed if they are idle for a long
-     enough time.
  =cut

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