Annotation of loncom/loncnew, revision 1.75

1.1       foxr        1: #!/usr/bin/perl
1.2       albertel    2: # The LearningOnline Network with CAPA
                      3: # lonc maintains the connections to remote computers
                      4: #
1.75    ! albertel    5: # $Id: loncnew,v 1.74 2006/01/27 20:37:12 albertel Exp $
1.2       albertel    6: #
                      7: # Copyright Michigan State University Board of Trustees
                      8: #
                      9: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
1.17      foxr       10: ## LON-CAPA is free software; you can redistribute it and/or modify
1.2       albertel   11: # it under the terms of the GNU General Public License as published by
                     12: # the Free Software Foundation; either version 2 of the License, or
                     13: # (at your option) any later version.
                     14: #
                     15: # LON-CAPA is distributed in the hope that it will be useful,
                     16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
                     17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     18: # GNU General Public License for more details.
                     19: #
                     20: # You should have received a copy of the GNU General Public License
                     21: # along with LON-CAPA; if not, write to the Free Software
                     22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
                     23: #
                     24: # /home/httpd/html/adm/gpl.txt
                     25: #
                     26: # http://www.lon-capa.org/
                     27: #
1.1       foxr       28: #
1.15      foxr       29: # new lonc handles n request out bver m connections to londs.
1.1       foxr       30: # This module is based on the Event class.
                     31: #   Development iterations:
                     32: #    - Setup basic event loop.   (done)
                     33: #    - Add timer dispatch.       (done)
                     34: #    - Add ability to accept lonc UNIX domain sockets.  (done)
                     35: #    - Add ability to create/negotiate lond connections (done).
1.7       foxr       36: #    - Add general logic for dispatching requests and timeouts. (done).
                     37: #    - Add support for the lonc/lond requests.          (done).
1.38      foxr       38: #    - Add logging/status monitoring.                    (done)
                     39: #    - Add Signal handling - HUP restarts. USR1 status report. (done)
1.7       foxr       40: #    - Add Configuration file I/O                       (done).
1.38      foxr       41: #    - Add management/status request interface.         (done)
1.8       foxr       42: #    - Add deferred request capability.                  (done)
1.38      foxr       43: #    - Detect transmission timeouts.                     (done)
1.7       foxr       44: #
                     45: 
1.23      foxr       46: use strict;
1.1       foxr       47: use lib "/home/httpd/lib/perl/";
                     48: use Event qw(:DEFAULT );
                     49: use POSIX qw(:signal_h);
1.12      foxr       50: use POSIX;
1.1       foxr       51: use IO::Socket;
                     52: use IO::Socket::INET;
                     53: use IO::Socket::UNIX;
1.9       foxr       54: use IO::File;
1.6       foxr       55: use IO::Handle;
1.1       foxr       56: use Socket;
                     57: use Crypt::IDEA;
                     58: use LONCAPA::Queue;
                     59: use LONCAPA::Stack;
                     60: use LONCAPA::LondConnection;
1.7       foxr       61: use LONCAPA::LondTransaction;
1.1       foxr       62: use LONCAPA::Configuration;
                     63: use LONCAPA::HashIterator;
1.67      albertel   64: use Fcntl qw(:flock);
1.1       foxr       65: 
                     66: 
                     67: # Read the httpd configuration file to get perl variables
                     68: # normally set in apache modules:
                     69: 
                     70: my $perlvarref = LONCAPA::Configuration::read_conf('loncapa.conf');
                     71: my %perlvar    = %{$perlvarref};
                     72: 
                     73: #
                     74: #  parent and shared variables.
                     75: 
                     76: my %ChildHash;			# by pid -> host.
1.26      foxr       77: my %HostToPid;			# By host -> pid.
                     78: my %HostHash;			# by loncapaname -> IP.
1.62      foxr       79: my %listening_to;		# Socket->host table for who the parent
                     80:                                 # is listening to.
                     81: my %parent_dispatchers;         # host-> listener watcher events. 
1.1       foxr       82: 
1.65      foxr       83: my %parent_handlers;		# Parent signal handlers...
                     84: 
1.9       foxr       85: my $MaxConnectionCount = 10;	# Will get from config later.
1.1       foxr       86: my $ClientConnection = 0;	# Uniquifier for client events.
                     87: 
1.9       foxr       88: my $DebugLevel = 0;
1.29      foxr       89: my $NextDebugLevel= 2;		# So Sigint can toggle this.
1.50      albertel   90: my $IdleTimeout= 600;		# Wait 10 minutes before pruning connections.
1.1       foxr       91: 
1.39      foxr       92: my $LogTransactions = 0;	# When True, all transactions/replies get logged.
1.65      foxr       93: my $executable      = $0;	# Get the full path to me.
1.39      foxr       94: 
1.1       foxr       95: #
                     96: #  The variables below are only used by the child processes.
                     97: #
                     98: my $RemoteHost;			# Name of host child is talking to.
1.20      albertel   99: my $UnixSocketDir= $perlvar{'lonSockDir'};
1.1       foxr      100: my $IdleConnections = Stack->new(); # Set of idle connections
                    101: my %ActiveConnections;		# Connections to the remote lond.
1.7       foxr      102: my %ActiveTransactions;		# LondTransactions in flight.
1.1       foxr      103: my %ActiveClients;		# Serial numbers of active clients by socket.
                    104: my $WorkQueue       = Queue->new(); # Queue of pending transactions.
                    105: my $ConnectionCount = 0;
1.4       foxr      106: my $IdleSeconds     = 0;	# Number of seconds idle.
1.9       foxr      107: my $Status          = "";	# Current status string.
1.14      foxr      108: my $RecentLogEntry  = "";
1.72      albertel  109: my $ConnectionRetries=5;	# Number of connection retries allowed.
                    110: my $ConnectionRetriesLeft=5;	# Number of connection retries remaining.
1.40      foxr      111: my $LondVersion     = "unknown"; # Version of lond we talk with.
1.49      foxr      112: my $KeyMode         = "";       # e.g. ssl, local, insecure from last connect.
1.54      foxr      113: my $LondConnecting  = 0;       # True when a connection is being built.
1.1       foxr      114: 
1.60      foxr      115: 
                    116: 
1.65      foxr      117: my $DieWhenIdle     = 1;	# When true children die when trimmed -> 0.
1.62      foxr      118: my $I_am_child      = 0;	# True if this is the child process.
1.57      foxr      119: 
1.1       foxr      120: #
1.9       foxr      121: #   The hash below gives the HTML format for log messages
                    122: #   given a severity.
                    123: #    
                    124: my %LogFormats;
                    125: 
1.45      albertel  126: $LogFormats{"CRITICAL"} = "<font color='red'>CRITICAL: %s</font>";
                    127: $LogFormats{"SUCCESS"}  = "<font color='green'>SUCCESS: %s</font>";
                    128: $LogFormats{"INFO"}     = "<font color='yellow'>INFO: %s</font>";
                    129: $LogFormats{"WARNING"}  = "<font color='blue'>WARNING: %s</font>";
1.9       foxr      130: $LogFormats{"DEFAULT"}  = " %s ";
                    131: 
1.10      foxr      132: 
1.57      foxr      133: #  UpdateStatus;
                    134: #    Update the idle status display to show how many connections
                    135: #    are left, retries and other stuff.
                    136: #
                    137: sub UpdateStatus {
                    138:     if ($ConnectionRetriesLeft > 0) {
                    139: 	ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
                    140: 		   ." Retries remaining: ".$ConnectionRetriesLeft
                    141: 		   ." ($KeyMode)");
                    142:     } else {
                    143: 	ShowStatus(GetServerHost()." >> DEAD <<");
                    144:     }
                    145: }
                    146: 
1.10      foxr      147: 
                    148: =pod
                    149: 
                    150: =head2 LogPerm
                    151: 
                    152: Makes an entry into the permanent log file.
                    153: 
                    154: =cut
1.69      matthew   155: 
1.10      foxr      156: sub LogPerm {
                    157:     my $message=shift;
                    158:     my $execdir=$perlvar{'lonDaemons'};
                    159:     my $now=time;
                    160:     my $local=localtime($now);
                    161:     my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
                    162:     print $fh "$now:$message:$local\n";
                    163: }
1.9       foxr      164: 
                    165: =pod
                    166: 
                    167: =head2 Log
                    168: 
                    169: Logs a message to the log file.
                    170: Parameters:
                    171: 
                    172: =item severity
                    173: 
                    174: One of CRITICAL, WARNING, INFO, SUCCESS used to select the
                    175: format string used to format the message.  if the severity is
                    176: not a defined severity the Default format string is used.
                    177: 
                    178: =item message
                    179: 
                    180: The base message.  In addtion to the format string, the message
                    181: will be appended to a string containing the name of our remote
                    182: host and the time will be formatted into the message.
                    183: 
                    184: =cut
                    185: 
                    186: sub Log {
1.47      foxr      187: 
                    188:     my ($severity, $message) = @_;
                    189: 
1.9       foxr      190:     if(!$LogFormats{$severity}) {
                    191: 	$severity = "DEFAULT";
                    192:     }
                    193: 
                    194:     my $format = $LogFormats{$severity};
                    195:     
                    196:     #  Put the window dressing in in front of the message format:
                    197: 
                    198:     my $now   = time;
                    199:     my $local = localtime($now);
                    200:     my $finalformat = "$local ($$) [$RemoteHost] [$Status] ";
                    201:     my $finalformat = $finalformat.$format."\n";
                    202: 
                    203:     # open the file and put the result.
                    204: 
                    205:     my $execdir = $perlvar{'lonDaemons'};
                    206:     my $fh      = IO::File->new(">>$execdir/logs/lonc.log");
                    207:     my $msg = sprintf($finalformat, $message);
1.14      foxr      208:     $RecentLogEntry = $msg;
1.9       foxr      209:     print $fh $msg;
                    210:     
1.10      foxr      211:     
1.9       foxr      212: }
1.6       foxr      213: 
1.3       albertel  214: 
1.1       foxr      215: =pod
1.3       albertel  216: 
                    217: =head2 GetPeerName
                    218: 
                    219: Returns the name of the host that a socket object is connected to.
                    220: 
1.1       foxr      221: =cut
                    222: 
                    223: sub GetPeername {
1.47      foxr      224: 
                    225: 
                    226:     my ($connection, $AdrFamily) = @_;
                    227: 
1.1       foxr      228:     my $peer       = $connection->peername();
                    229:     my $peerport;
                    230:     my $peerip;
                    231:     if($AdrFamily == AF_INET) {
                    232: 	($peerport, $peerip) = sockaddr_in($peer);
1.23      foxr      233: 	my $peername    = gethostbyaddr($peerip, $AdrFamily);
1.1       foxr      234: 	return $peername;
                    235:     } elsif ($AdrFamily == AF_UNIX) {
                    236: 	my $peerfile;
                    237: 	($peerfile) = sockaddr_un($peer);
                    238: 	return $peerfile;
                    239:     }
                    240: }
                    241: =pod
1.3       albertel  242: 
1.1       foxr      243: =head2 Debug
1.3       albertel  244: 
                    245: Invoked to issue a debug message.
                    246: 
1.1       foxr      247: =cut
1.3       albertel  248: 
1.1       foxr      249: sub Debug {
1.47      foxr      250: 
                    251:     my ($level, $message) = @_;
                    252: 
1.1       foxr      253:     if ($level <= $DebugLevel) {
1.23      foxr      254: 	Log("INFO", "-Debug- $message host = $RemoteHost");
1.1       foxr      255:     }
                    256: }
                    257: 
                    258: sub SocketDump {
1.47      foxr      259: 
                    260:     my ($level, $socket) = @_;
                    261: 
1.1       foxr      262:     if($level <= $DebugLevel) {
1.48      foxr      263: 	$socket->Dump(-1);	# Ensure it will get dumped.
1.1       foxr      264:     }
                    265: }
1.3       albertel  266: 
1.1       foxr      267: =pod
1.3       albertel  268: 
1.5       foxr      269: =head2 ShowStatus
                    270: 
                    271:  Place some text as our pid status.
1.10      foxr      272:  and as what we return in a SIGUSR1
1.5       foxr      273: 
                    274: =cut
1.69      matthew   275: 
1.5       foxr      276: sub ShowStatus {
1.10      foxr      277:     my $state = shift;
                    278:     my $now = time;
                    279:     my $local = localtime($now);
                    280:     $Status   = $local.": ".$state;
                    281:     $0='lonc: '.$state.' '.$local;
1.5       foxr      282: }
                    283: 
                    284: =pod
                    285: 
1.69      matthew   286: =head2 SocketTimeout
1.15      foxr      287: 
                    288:     Called when an action on the socket times out.  The socket is 
                    289:    destroyed and any active transaction is failed.
                    290: 
                    291: 
                    292: =cut
1.69      matthew   293: 
1.15      foxr      294: sub SocketTimeout {
                    295:     my $Socket = shift;
1.38      foxr      296:     Log("WARNING", "A socket timeout was detected");
1.52      foxr      297:     Debug(5, " SocketTimeout called: ");
1.48      foxr      298:     $Socket->Dump(0);
1.42      foxr      299:     if(exists($ActiveTransactions{$Socket})) {
1.43      albertel  300: 	FailTransaction($ActiveTransactions{$Socket});
1.42      foxr      301:     }
1.22      foxr      302:     KillSocket($Socket);	# A transaction timeout also counts as
                    303:                                 # a connection failure:
                    304:     $ConnectionRetriesLeft--;
1.42      foxr      305:     if($ConnectionRetriesLeft <= 0) {
1.52      foxr      306: 	Log("CRITICAL", "Host marked DEAD: ".GetServerHost());
1.56      foxr      307: 	$LondConnecting = 0;
1.42      foxr      308:     }
                    309: 
1.15      foxr      310: }
1.64      foxr      311: #
                    312: #   This function should be called by the child in all cases where it must
                    313: #   exit.  If the child process is running with the DieWhenIdle turned on
                    314: #   it must create a lock file for the AF_UNIX socket in order to prevent
                    315: #   connection requests from lonnet in the time between process exit
                    316: #   and the parent picking up the listen again.
                    317: # Parameters:
                    318: #     exit_code           - Exit status value, however see the next parameter.
                    319: #     message             - If this optional parameter is supplied, the exit
                    320: #                           is via a die with this message.
                    321: #
                    322: sub child_exit {
                    323:     my ($exit_code, $message) = @_;
                    324: 
                    325:     # Regardless of how we exit, we may need to do the lock thing:
                    326: 
                    327:     if($DieWhenIdle) {
                    328: 	#
                    329: 	#  Create a lock file since there will be a time window
                    330: 	#  between our exit and the parent's picking up the listen
                    331: 	#  during which no listens will be done on the
                    332: 	#  lonnet client socket.
                    333: 	#
                    334: 	my $lock_file = GetLoncSocketPath().".lock";
                    335: 	open(LOCK,">$lock_file");
                    336: 	print LOCK "Contents not important";
                    337: 	close(LOCK);
                    338: 	
                    339: 	exit(0);
                    340:     }
                    341:     #  Now figure out how we exit:
                    342: 
                    343:     if($message) {
                    344: 	die $message;
                    345:     } else {
                    346: 	exit($exit_code);
                    347:     }
                    348: }
1.35      foxr      349: #----------------------------- Timer management ------------------------
1.15      foxr      350: 
                    351: =pod
                    352: 
1.1       foxr      353: =head2 Tick
1.3       albertel  354: 
                    355: Invoked  each timer tick.
                    356: 
1.1       foxr      357: =cut
                    358: 
1.5       foxr      359: 
1.1       foxr      360: sub Tick {
1.52      foxr      361:     my ($Event)       = @_;
                    362:     my $clock_watcher = $Event->w;
                    363: 
1.1       foxr      364:     my $client;
1.57      foxr      365:     UpdateStatus();
                    366: 
1.4       foxr      367:     # Is it time to prune connection count:
                    368: 
                    369: 
                    370:     if($IdleConnections->Count()  && 
                    371:        ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
1.52      foxr      372: 	$IdleSeconds++;
1.4       foxr      373: 	if($IdleSeconds > $IdleTimeout) { # Prune a connection...
1.23      foxr      374: 	    my $Socket = $IdleConnections->pop();
1.6       foxr      375: 	    KillSocket($Socket);
1.54      foxr      376: 	    $IdleSeconds = 0;	# Otherwise all connections get trimmed to fast.
1.57      foxr      377: 	    UpdateStatus();
                    378: 	    if(($ConnectionCount == 0) && $DieWhenIdle) {
1.64      foxr      379: 		&child_exit(0);
                    380: 
1.57      foxr      381: 	    }
1.4       foxr      382: 	}
                    383:     } else {
                    384: 	$IdleSeconds = 0;	# Reset idle count if not idle.
                    385:     }
1.15      foxr      386:     #
                    387:     #  For each inflight transaction, tick down its timeout counter.
                    388:     #
1.35      foxr      389: 
1.34      albertel  390:     foreach my $item (keys %ActiveConnections) {
                    391: 	my $State = $ActiveConnections{$item}->data->GetState();
1.35      foxr      392: 	if ($State ne 'Idle') {
1.34      albertel  393: 	    Debug(5,"Ticking Socket $State $item");
                    394: 	    $ActiveConnections{$item}->data->Tick();
                    395: 	}
1.15      foxr      396:     }
1.5       foxr      397:     # Do we have work in the queue, but no connections to service them?
                    398:     # If so, try to make some new connections to get things going again.
                    399:     #
1.57      foxr      400:     #   Note this code is dead now...
                    401:     #
1.5       foxr      402:     my $Requests = $WorkQueue->Count();
1.56      foxr      403:     if (($ConnectionCount == 0)  && ($Requests > 0) && (!$LondConnecting)) { 
1.10      foxr      404: 	if ($ConnectionRetriesLeft > 0) {
1.56      foxr      405: 	    Debug(5,"Work but no connections, Make a new one");
                    406: 	    my $success;
                    407: 	    $success    = &MakeLondConnection;
                    408: 	    if($success == 0) { # All connections failed:
1.29      foxr      409: 		Debug(5,"Work in queue failed to make any connectiouns\n");
1.22      foxr      410: 		EmptyQueue();	# Fail pending transactions with con_lost.
1.42      foxr      411: 		CloseAllLondConnections(); # Should all be closed but....
1.10      foxr      412: 	    }
                    413: 	} else {
1.56      foxr      414: 	    $LondConnecting = 0;
1.22      foxr      415: 	    ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
1.29      foxr      416: 	    Debug(5,"Work in queue, but gave up on connections..flushing\n");
1.10      foxr      417: 	    EmptyQueue();	# Connections can't be established.
1.42      foxr      418: 	    CloseAllLondConnections(); # Should all already be closed but...
1.5       foxr      419: 	}
                    420:        
                    421:     }
1.49      foxr      422:     if ($ConnectionCount == 0) {
                    423: 	$KeyMode = ""; 
1.52      foxr      424: 	$clock_watcher->cancel();
1.49      foxr      425:     }
1.66      albertel  426:     &UpdateStatus();
1.1       foxr      427: }
                    428: 
                    429: =pod
1.3       albertel  430: 
1.1       foxr      431: =head2 SetupTimer
                    432: 
1.3       albertel  433: Sets up a 1 per sec recurring timer event.  The event handler is used to:
1.1       foxr      434: 
1.3       albertel  435: =item
                    436: 
                    437: Trigger timeouts on communications along active sockets.
                    438: 
                    439: =item
                    440: 
                    441: Trigger disconnections of idle sockets.
1.1       foxr      442: 
                    443: =cut
                    444: 
                    445: sub SetupTimer {
1.52      foxr      446:     Debug(6, "SetupTimer");
                    447:     Event->timer(interval => 1, cb => \&Tick );
1.1       foxr      448: }
1.3       albertel  449: 
1.1       foxr      450: =pod
1.3       albertel  451: 
1.1       foxr      452: =head2 ServerToIdle
1.3       albertel  453: 
                    454: This function is called when a connection to the server is
                    455: ready for more work.
                    456: 
                    457: If there is work in the Work queue the top element is dequeued
1.1       foxr      458: and the connection will start to work on it.  If the work queue is
                    459: empty, the connection is pushed on the idle connection stack where
                    460: it will either get another work unit, or alternatively, if it sits there
                    461: long enough, it will be shut down and released.
                    462: 
1.3       albertel  463: =cut
1.1       foxr      464: 
                    465: sub ServerToIdle {
                    466:     my $Socket   = shift;	# Get the socket.
1.49      foxr      467:     $KeyMode = $Socket->{AuthenticationMode};
1.7       foxr      468:     delete($ActiveTransactions{$Socket}); # Server has no transaction
1.1       foxr      469: 
1.29      foxr      470:     &Debug(5, "Server to idle");
1.1       foxr      471: 
                    472:     #  If there's work to do, start the transaction:
                    473: 
1.23      foxr      474:     my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
1.29      foxr      475:     if ($reqdata ne undef)  {
                    476: 	Debug(5, "Queue gave request data: ".$reqdata->getRequest());
1.7       foxr      477: 	&StartRequest($Socket,  $reqdata);
1.8       foxr      478: 
1.1       foxr      479:     } else {
                    480: 	
                    481:     #  There's no work waiting, so push the server to idle list.
1.29      foxr      482: 	&Debug(5, "No new work requests, server connection going idle");
1.1       foxr      483: 	$IdleConnections->push($Socket);
                    484:     }
                    485: }
1.3       albertel  486: 
1.1       foxr      487: =pod
1.3       albertel  488: 
1.1       foxr      489: =head2 ClientWritable
1.3       albertel  490: 
                    491: Event callback for when a client socket is writable.
                    492: 
                    493: This callback is established when a transaction reponse is
                    494: avaiable from lond.  The response is forwarded to the unix socket
                    495: as it becomes writable in this sub.
                    496: 
1.1       foxr      497: Parameters:
                    498: 
1.3       albertel  499: =item Event
                    500: 
                    501: The event that has been triggered. Event->w->data is
                    502: the data and Event->w->fd is the socket to write.
1.1       foxr      503: 
                    504: =cut
1.3       albertel  505: 
1.1       foxr      506: sub ClientWritable {
                    507:     my $Event    = shift;
                    508:     my $Watcher  = $Event->w;
                    509:     my $Data     = $Watcher->data;
                    510:     my $Socket   = $Watcher->fd;
                    511: 
                    512:     # Try to send the data:
                    513: 
                    514:     &Debug(6, "ClientWritable writing".$Data);
                    515:     &Debug(9, "Socket is: ".$Socket);
                    516: 
1.6       foxr      517:     if($Socket->connected) {
                    518: 	my $result = $Socket->send($Data, 0);
                    519: 	
                    520: 	# $result undefined: the write failed.
                    521: 	# otherwise $result is the number of bytes written.
                    522: 	# Remove that preceding string from the data.
                    523: 	# If the resulting data is empty, destroy the watcher
                    524: 	# and set up a read event handler to accept the next
                    525: 	# request.
                    526: 	
                    527: 	&Debug(9,"Send result is ".$result." Defined: ".defined($result));
1.29      foxr      528: 	if($result ne undef) {
1.6       foxr      529: 	    &Debug(9, "send result was defined");
                    530: 	    if($result == length($Data)) { # Entire string sent.
                    531: 		&Debug(9, "ClientWritable data all written");
                    532: 		$Watcher->cancel();
                    533: 		#
                    534: 		#  Set up to read next request from socket:
                    535: 		
                    536: 		my $descr     = sprintf("Connection to lonc client %d",
                    537: 					$ActiveClients{$Socket});
                    538: 		Event->io(cb    => \&ClientRequest,
                    539: 			  poll  => 'r',
                    540: 			  desc  => $descr,
                    541: 			  data  => "",
                    542: 			  fd    => $Socket);
                    543: 		
                    544: 	    } else {		# Partial string sent.
                    545: 		$Watcher->data(substr($Data, $result));
1.15      foxr      546: 		if($result == 0) {    # client hung up on us!!
1.52      foxr      547: 		    # Log("INFO", "lonc pipe client hung up on us!");
1.15      foxr      548: 		    $Watcher->cancel;
                    549: 		    $Socket->shutdown(2);
                    550: 		    $Socket->close();
                    551: 		}
1.6       foxr      552: 	    }
                    553: 	    
                    554: 	} else {			# Error of some sort...
                    555: 	    
                    556: 	    # Some errnos are possible:
                    557: 	    my $errno = $!;
                    558: 	    if($errno == POSIX::EWOULDBLOCK   ||
                    559: 	       $errno == POSIX::EAGAIN        ||
                    560: 	       $errno == POSIX::EINTR) {
                    561: 		# No action taken?
                    562: 	    } else {		# Unanticipated errno.
                    563: 		&Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
                    564: 		$Watcher->cancel;	# Stop the watcher.
                    565: 		$Socket->shutdown(2); # Kill connection
                    566: 		$Socket->close();	# Close the socket.
                    567: 	    }
1.1       foxr      568: 	    
                    569: 	}
1.6       foxr      570:     } else {
                    571: 	$Watcher->cancel();	# A delayed request...just cancel.
1.1       foxr      572:     }
                    573: }
                    574: 
                    575: =pod
1.3       albertel  576: 
1.1       foxr      577: =head2 CompleteTransaction
1.3       albertel  578: 
                    579: Called when the reply data has been received for a lond 
1.1       foxr      580: transaction.   The reply data must now be sent to the
                    581: ultimate client on the other end of the Unix socket.  This is
                    582: done by setting up a writable event for the socket with the
                    583: data the reply data.
1.3       albertel  584: 
1.1       foxr      585: Parameters:
1.3       albertel  586: 
                    587: =item Socket
                    588: 
                    589: Socket on which the lond transaction occured.  This is a
                    590: LondConnection. The data received is in the TransactionReply member.
                    591: 
1.7       foxr      592: =item Transaction
1.3       albertel  593: 
1.7       foxr      594: The transaction that is being completed.
1.1       foxr      595: 
                    596: =cut
1.3       albertel  597: 
1.1       foxr      598: sub CompleteTransaction {
1.29      foxr      599:     &Debug(5,"Complete transaction");
1.47      foxr      600: 
                    601:     my ($Socket, $Transaction) = @_;
1.1       foxr      602: 
1.7       foxr      603:     if (!$Transaction->isDeferred()) { # Normal transaction
                    604: 	my $data   = $Socket->GetReply(); # Data to send.
1.39      foxr      605: 	if($LogTransactions) {
                    606: 	    Log("SUCCESS", "Reply from lond: '$data'");
                    607: 	}
1.7       foxr      608: 	StartClientReply($Transaction, $data);
                    609:     } else {			# Delete deferred transaction file.
1.9       foxr      610: 	Log("SUCCESS", "A delayed transaction was completed");
1.23      foxr      611: 	LogPerm("S:$Transaction->getClient() :".$Transaction->getRequest());
1.7       foxr      612: 	unlink $Transaction->getFile();
                    613:     }
1.6       foxr      614: }
1.42      foxr      615: 
1.6       foxr      616: =pod
1.42      foxr      617: 
1.6       foxr      618: =head1 StartClientReply
                    619: 
                    620:    Initiates a reply to a client where the reply data is a parameter.
                    621: 
1.7       foxr      622: =head2  parameters:
                    623: 
                    624: =item Transaction
                    625: 
                    626:     The transaction for which we are responding to the client.
                    627: 
                    628: =item data
                    629: 
                    630:     The data to send to apached client.
                    631: 
1.6       foxr      632: =cut
1.42      foxr      633: 
1.6       foxr      634: sub StartClientReply {
1.1       foxr      635: 
1.47      foxr      636:     my ($Transaction, $data) = @_;
1.12      foxr      637: 
1.7       foxr      638:     my $Client   = $Transaction->getClient();
                    639: 
1.1       foxr      640:     &Debug(8," Reply was: ".$data);
                    641:     my $Serial         = $ActiveClients{$Client};
                    642:     my $desc           = sprintf("Connection to lonc client %d",
                    643: 				 $Serial);
                    644:     Event->io(fd       => $Client,
                    645: 	      poll     => "w",
                    646: 	      desc     => $desc,
                    647: 	      cb       => \&ClientWritable,
                    648: 	      data     => $data);
                    649: }
1.42      foxr      650: 
1.4       foxr      651: =pod
1.42      foxr      652: 
1.4       foxr      653: =head2 FailTransaction
                    654: 
                    655:   Finishes a transaction with failure because the associated lond socket
1.7       foxr      656:   disconnected.  There are two possibilities:
                    657:   - The transaction is deferred: in which case we just quietly
                    658:     delete the transaction since there is no client connection.
                    659:   - The transaction is 'live' in which case we initiate the sending
                    660:     of "con_lost" to the client.
                    661: 
1.42      foxr      662: Deleting the transaction means killing it from the %ActiveTransactions hash.
1.4       foxr      663: 
                    664: Parameters:
                    665: 
                    666: =item client  
                    667:  
1.7       foxr      668:    The LondTransaction we are failing.
                    669:  
1.42      foxr      670: 
1.4       foxr      671: =cut
                    672: 
                    673: sub FailTransaction {
1.7       foxr      674:     my $transaction = shift;
1.52      foxr      675:     
                    676:     #  If the socket is dead, that's already logged.
                    677: 
                    678:     if ($ConnectionRetriesLeft > 0) {
                    679: 	Log("WARNING", "Failing transaction "
1.71      albertel  680: 	    .$transaction->getLoggableRequest());
1.52      foxr      681:     }
1.71      albertel  682:     Debug(1, "Failing transaction: ".$transaction->getLoggableRequest());
1.10      foxr      683:     if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
1.11      foxr      684: 	my $client  = $transaction->getClient();
1.30      foxr      685: 	Debug(1," Replying con_lost to ".$transaction->getRequest());
1.11      foxr      686: 	StartClientReply($transaction, "con_lost\n");
1.7       foxr      687:     }
1.4       foxr      688: 
                    689: }
                    690: 
                    691: =pod
1.69      matthew   692: 
1.6       foxr      693: =head1  EmptyQueue
1.7       foxr      694: 
1.6       foxr      695:   Fails all items in the work queue with con_lost.
1.7       foxr      696:   Note that each item in the work queue is a transaction.
                    697: 
1.6       foxr      698: =cut
1.69      matthew   699: 
1.6       foxr      700: sub EmptyQueue {
1.22      foxr      701:     $ConnectionRetriesLeft--;	# Counts as connection failure too.
1.6       foxr      702:     while($WorkQueue->Count()) {
1.10      foxr      703: 	my $request = $WorkQueue->dequeue(); # This is a transaction
1.7       foxr      704: 	FailTransaction($request);
1.6       foxr      705:     }
                    706: }
                    707: 
                    708: =pod
1.4       foxr      709: 
1.9       foxr      710: =head2 CloseAllLondConnections
                    711: 
                    712: Close all connections open on lond prior to exit e.g.
                    713: 
                    714: =cut
1.69      matthew   715: 
1.9       foxr      716: sub CloseAllLondConnections {
1.23      foxr      717:     foreach my $Socket (keys %ActiveConnections) {
1.42      foxr      718:       if(exists($ActiveTransactions{$Socket})) {
                    719: 	FailTransaction($ActiveTransactions{$Socket});
                    720:       }
                    721:       KillSocket($Socket);
1.9       foxr      722:     }
                    723: }
                    724: 
                    725: =pod
                    726: 
1.4       foxr      727: =head2 KillSocket
                    728:  
                    729: Destroys a socket.  This function can be called either when a socket
                    730: has died of 'natural' causes or because a socket needs to be pruned due to
                    731: idleness.  If the socket has died naturally, if there are no longer any 
                    732: live connections a new connection is created (in case there are transactions
                    733: in the queue).  If the socket has been pruned, it is never re-created.
                    734: 
                    735: Parameters:
1.1       foxr      736: 
1.4       foxr      737: =item Socket
                    738:  
                    739:   The socket to kill off.
                    740: 
                    741: =item Restart
                    742: 
                    743: nonzero if we are allowed to create a new connection.
                    744: 
1.69      matthew   745: =cut
1.4       foxr      746: 
                    747: sub KillSocket {
                    748:     my $Socket = shift;
                    749: 
1.17      foxr      750:     Log("WARNING", "Shutting down a socket");
1.9       foxr      751:     $Socket->Shutdown();
                    752: 
1.7       foxr      753:     #  If the socket came from the active connection set,
                    754:     #  delete its transaction... note that FailTransaction should
                    755:     #  already have been called!!!
                    756:     #  otherwise it came from the idle set.
                    757:     #  
1.4       foxr      758:     
                    759:     if(exists($ActiveTransactions{$Socket})) {
                    760: 	delete ($ActiveTransactions{$Socket});
                    761:     }
                    762:     if(exists($ActiveConnections{$Socket})) {
                    763: 	delete($ActiveConnections{$Socket});
1.37      albertel  764: 	$ConnectionCount--;
                    765: 	if ($ConnectionCount < 0) { $ConnectionCount = 0; }
1.4       foxr      766:     }
1.6       foxr      767:     #  If the connection count has gone to zero and there is work in the
                    768:     #  work queue, the work all gets failed with con_lost.
                    769:     #
                    770:     if($ConnectionCount == 0) {
1.22      foxr      771: 	EmptyQueue();
1.42      foxr      772: 	CloseAllLondConnections; # Should all already be closed but...
1.4       foxr      773:     }
                    774: }
1.1       foxr      775: 
                    776: =pod
1.3       albertel  777: 
1.1       foxr      778: =head2 LondReadable
1.3       albertel  779: 
1.1       foxr      780: This function is called whenever a lond connection
                    781: is readable.  The action is state dependent:
                    782: 
1.3       albertel  783: =head3 State=Initialized
                    784: 
                    785: We''re waiting for the challenge, this is a no-op until the
1.1       foxr      786: state changes.
1.3       albertel  787: 
1.1       foxr      788: =head3 State=Challenged 
1.3       albertel  789: 
                    790: The challenge has arrived we need to transition to Writable.
1.1       foxr      791: The connection must echo the challenge back.
1.3       albertel  792: 
1.1       foxr      793: =head3 State=ChallengeReplied
1.3       albertel  794: 
                    795: The challenge has been replied to.  The we are receiveing the 
1.1       foxr      796: 'ok' from the partner.
1.3       albertel  797: 
1.40      foxr      798: =head3  State=ReadingVersionString
                    799: 
                    800: We have requested the lond version and are reading the
                    801: version back.  Upon completion, we'll store the version away
                    802: for future use(?).
                    803: 
                    804: =head3 State=HostSet
                    805: 
                    806: We have selected the domain name of our peer (multhomed hosts)
                    807: and are getting the reply (presumably ok) back.
                    808: 
1.1       foxr      809: =head3 State=RequestingKey
1.3       albertel  810: 
                    811: The ok has been received and we need to send the request for
1.1       foxr      812: an encryption key.  Transition to writable for that.
1.3       albertel  813: 
1.1       foxr      814: =head3 State=ReceivingKey
1.3       albertel  815: 
                    816: The the key has been requested, now we are reading the new key.
                    817: 
1.1       foxr      818: =head3 State=Idle 
1.3       albertel  819: 
                    820: The encryption key has been negotiated or we have finished 
1.1       foxr      821: reading data from the a transaction.   If the callback data has
                    822: a client as well as the socket iformation, then we are 
                    823: doing a transaction and the data received is relayed to the client
                    824: before the socket is put on the idle list.
1.3       albertel  825: 
1.1       foxr      826: =head3 State=SendingRequest
1.3       albertel  827: 
                    828: I do not think this state can be received here, but if it is,
1.1       foxr      829: the appropriate thing to do is to transition to writable, and send
                    830: the request.
1.3       albertel  831: 
1.1       foxr      832: =head3 State=ReceivingReply
1.3       albertel  833: 
                    834: We finished sending the request to the server and now transition
1.1       foxr      835: to readable to receive the reply. 
                    836: 
                    837: The parameter to this function are:
1.3       albertel  838: 
1.1       foxr      839: The event. Implicit in this is the watcher and its data.  The data 
                    840: contains at least the lond connection object and, if a 
                    841: transaction is in progress, the socket attached to the local client.
                    842: 
1.3       albertel  843: =cut
1.1       foxr      844: 
                    845: sub LondReadable {
1.8       foxr      846: 
1.41      albertel  847:     my $Event      = shift;
                    848:     my $Watcher    = $Event->w;
                    849:     my $Socket     = $Watcher->data;
                    850:     my $client     = undef;
1.40      foxr      851: 
1.41      albertel  852:     &Debug(6,"LondReadable called state = ".$Socket->GetState());
1.40      foxr      853: 
                    854: 
1.41      albertel  855:     my $State = $Socket->GetState(); # All action depends on the state.
1.40      foxr      856: 
1.41      albertel  857:     SocketDump(6, $Socket);
                    858:     my $status = $Socket->Readable();
1.40      foxr      859: 
1.41      albertel  860:     &Debug(2, "Socket->Readable returned: $status");
1.40      foxr      861: 
1.41      albertel  862:     if($status != 0) {
                    863: 	# bad return from socket read. Currently this means that
                    864: 	# The socket has become disconnected. We fail the transaction.
1.40      foxr      865: 
1.41      albertel  866: 	Log("WARNING",
                    867: 	    "Lond connection lost.");
                    868: 	if(exists($ActiveTransactions{$Socket})) {
                    869: 	    FailTransaction($ActiveTransactions{$Socket});
1.56      foxr      870: 	} else {
                    871: 	    #  Socket is connecting and failed... need to mark
                    872: 	    #  no longer connecting.
                    873: 	   
                    874: 	    $LondConnecting = 0;
1.41      albertel  875: 	}
                    876: 	$Watcher->cancel();
                    877: 	KillSocket($Socket);
                    878: 	$ConnectionRetriesLeft--;       # Counts as connection failure
                    879: 	return;
                    880:     }
                    881:     SocketDump(6,$Socket);
1.17      foxr      882: 
1.41      albertel  883:     $State = $Socket->GetState(); # Update in case of transition.
                    884:     &Debug(6, "After read, state is ".$State);
1.1       foxr      885: 
1.41      albertel  886:     if($State eq "Initialized") {
1.1       foxr      887: 
                    888: 
1.41      albertel  889:     } elsif ($State eq "ChallengeReceived") {
1.1       foxr      890: 	#  The challenge must be echoed back;  The state machine
                    891: 	# in the connection takes care of setting that up.  Just
                    892: 	# need to transition to writable:
1.41      albertel  893: 	
                    894: 	$Watcher->cb(\&LondWritable);
                    895: 	$Watcher->poll("w");
1.1       foxr      896: 
1.41      albertel  897:     } elsif ($State eq "ChallengeReplied") {
1.1       foxr      898: 
1.41      albertel  899:     } elsif ($State eq "RequestingVersion") {
                    900: 	# Need to ask for the version... that is writiability:
1.1       foxr      901: 
1.41      albertel  902: 	$Watcher->cb(\&LondWritable);
                    903: 	$Watcher->poll("w");
                    904: 
                    905:     } elsif ($State eq "ReadingVersionString") {
                    906: 	# Read the rest of the version string... 
                    907:     } elsif ($State eq "SetHost") {
                    908: 	# Need to request the actual domain get set...
                    909: 
                    910: 	$Watcher->cb(\&LondWritable);
                    911: 	$Watcher->poll("w");
                    912:     } elsif ($State eq "HostSet") {
                    913: 	# Reading the 'ok' from the peer.
                    914: 
                    915:     } elsif ($State eq "RequestingKey") {
1.1       foxr      916: 	#  The ok was received.  Now we need to request the key
                    917: 	#  That requires us to be writable:
                    918: 
1.41      albertel  919: 	$Watcher->cb(\&LondWritable);
                    920: 	$Watcher->poll("w");
1.1       foxr      921: 
1.41      albertel  922:     } elsif ($State eq "ReceivingKey") {
1.1       foxr      923: 
1.41      albertel  924:     } elsif ($State eq "Idle") {
1.40      foxr      925:    
1.41      albertel  926: 	# This is as good a spot as any to get the peer version
                    927: 	# string:
1.40      foxr      928:    
1.41      albertel  929: 	if($LondVersion eq "unknown") {
                    930: 	    $LondVersion = $Socket->PeerVersion();
                    931: 	    Log("INFO", "Connected to lond version: $LondVersion");
                    932: 	}
1.1       foxr      933: 	# If necessary, complete a transaction and then go into the
                    934: 	# idle queue.
1.22      foxr      935: 	#  Note that a trasition to idle indicates a live lond
                    936: 	# on the other end so reset the connection retries.
                    937: 	#
1.41      albertel  938: 	$ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
                    939: 	$Watcher->cancel();
                    940: 	if(exists($ActiveTransactions{$Socket})) {
                    941: 	    Debug(5,"Completing transaction!!");
                    942: 	    CompleteTransaction($Socket, 
                    943: 				$ActiveTransactions{$Socket});
                    944: 	} else {
                    945: 	    Log("SUCCESS", "Connection ".$ConnectionCount." to "
                    946: 		.$RemoteHost." now ready for action");
                    947: 	}
                    948: 	ServerToIdle($Socket);	# Next work unit or idle.
1.54      foxr      949: 
                    950: 	#
                    951: 	$LondConnecting = 0;	# Best spot I can think of for this.
                    952: 	# 
1.6       foxr      953: 	
1.41      albertel  954:     } elsif ($State eq "SendingRequest") {
1.1       foxr      955: 	#  We need to be writable for this and probably don't belong
                    956: 	#  here inthe first place.
                    957: 
1.73      albertel  958: 	Debug(6, "SendingRequest state encountered in readable");
1.41      albertel  959: 	$Watcher->poll("w");
                    960: 	$Watcher->cb(\&LondWritable);
1.1       foxr      961: 
1.41      albertel  962:     } elsif ($State eq "ReceivingReply") {
1.1       foxr      963: 
                    964: 
1.41      albertel  965:     } else {
                    966: 	# Invalid state.
                    967: 	Debug(4, "Invalid state in LondReadable");
                    968:     }
1.1       foxr      969: }
1.3       albertel  970: 
1.1       foxr      971: =pod
1.3       albertel  972: 
1.1       foxr      973: =head2 LondWritable
1.3       albertel  974: 
1.1       foxr      975: This function is called whenever a lond connection
                    976: becomes writable while there is a writeable monitoring
                    977: event.  The action taken is very state dependent:
1.3       albertel  978: 
1.1       foxr      979: =head3 State = Connected 
1.3       albertel  980: 
                    981: The connection is in the process of sending the 'init' hailing to the
                    982: lond on the remote end.  The connection object''s Writable member is
                    983: called.  On error, ConnectionError is called to destroy the connection
                    984: and remove it from the ActiveConnections hash
                    985: 
1.1       foxr      986: =head3 Initialized
1.3       albertel  987: 
                    988: 'init' has been sent, writability monitoring is removed and
                    989: readability monitoring is started with LondReadable as the callback.
                    990: 
1.1       foxr      991: =head3 ChallengeReceived
1.3       albertel  992: 
                    993: The connection has received the who are you challenge from the remote
                    994: system, and is in the process of sending the challenge
                    995: response. Writable is called.
                    996: 
1.1       foxr      997: =head3 ChallengeReplied
1.3       albertel  998: 
                    999: The connection has replied to the initial challenge The we switch to
                   1000: monitoring readability looking for the server to reply with 'ok'.
                   1001: 
1.1       foxr     1002: =head3 RequestingKey
1.3       albertel 1003: 
                   1004: The connection is in the process of requesting its encryption key.
                   1005: Writable is called.
                   1006: 
1.1       foxr     1007: =head3 ReceivingKey
1.3       albertel 1008: 
                   1009: The connection has sent the request for a key.  Switch to readability
                   1010: monitoring to accept the key
                   1011: 
1.1       foxr     1012: =head3 SendingRequest
1.3       albertel 1013: 
                   1014: The connection is in the process of sending a request to the server.
                   1015: This request is part of a client transaction.  All the states until
                   1016: now represent the client setup protocol. Writable is called.
                   1017: 
1.1       foxr     1018: =head3 ReceivingReply
                   1019: 
1.3       albertel 1020: The connection has sent a request.  Now it must receive a reply.
                   1021: Readability monitoring is requested.
                   1022: 
                   1023: This function is an event handler and therefore receives as
1.1       foxr     1024: a parameter the event that has fired.  The data for the watcher
                   1025: of this event is a reference to a list of one or two elements,
                   1026: depending on state. The first (and possibly only) element is the
                   1027: socket.  The second (present only if a request is in progress)
                   1028: is the socket on which to return a reply to the caller.
                   1029: 
                   1030: =cut
1.3       albertel 1031: 
1.1       foxr     1032: sub LondWritable {
                   1033:     my $Event   = shift;
                   1034:     my $Watcher = $Event->w;
1.8       foxr     1035:     my $Socket  = $Watcher->data;
                   1036:     my $State   = $Socket->GetState();
1.1       foxr     1037: 
1.8       foxr     1038:     Debug(6,"LondWritable State = ".$State."\n");
1.1       foxr     1039: 
1.8       foxr     1040:  
1.1       foxr     1041:     #  Figure out what to do depending on the state of the socket:
                   1042:     
                   1043: 
                   1044: 
                   1045: 
                   1046:     SocketDump(6,$Socket);
                   1047: 
1.42      foxr     1048:     #  If the socket is writable, we must always write.
                   1049:     # Only by writing will we undergo state transitions.
                   1050:     # Old logic wrote in state specific code below, however
                   1051:     # That forces us at least through another invocation of
                   1052:     # this function after writability is possible again.
                   1053:     # This logic also factors out common code for handling
                   1054:     # write failures... in all cases, write failures 
                   1055:     # Kill the socket.
                   1056:     #  This logic makes the branches of the >big< if below
                   1057:     # so that the writing states are actually NO-OPs.
                   1058: 
                   1059:     if ($Socket->Writable() != 0) {
1.43      albertel 1060: 	#  The write resulted in an error.
                   1061: 	# We'll treat this as if the socket got disconnected:
                   1062: 	Log("WARNING", "Connection to ".$RemoteHost.
                   1063: 	    " has been disconnected");
                   1064: 	if(exists($ActiveTransactions{$Socket})) {
                   1065: 	    FailTransaction($ActiveTransactions{$Socket});
1.56      foxr     1066: 	} else {
                   1067: 	    #  In the process of conneting, so need to turn that off.
                   1068: 	    
                   1069: 	    $LondConnecting = 0;
1.43      albertel 1070: 	}
                   1071: 	$Watcher->cancel();
                   1072: 	KillSocket($Socket);
                   1073: 	return;
1.42      foxr     1074:     }
                   1075: 
                   1076: 
                   1077: 
1.41      albertel 1078:     if      ($State eq "Connected")         {
1.1       foxr     1079: 
1.41      albertel 1080: 	#  "init" is being sent...
1.42      foxr     1081:  
1.41      albertel 1082:     } elsif ($State eq "Initialized")       {
1.4       foxr     1083: 
1.41      albertel 1084: 	# Now that init was sent, we switch 
                   1085: 	# to watching for readability:
1.1       foxr     1086: 
1.41      albertel 1087: 	$Watcher->cb(\&LondReadable);
                   1088: 	$Watcher->poll("r");
                   1089: 	
                   1090:     } elsif ($State eq "ChallengeReceived") {
                   1091: 	# We received the challenge, now we 
                   1092: 	# are echoing it back. This is a no-op,
                   1093: 	# we're waiting for the state to change
1.1       foxr     1094: 	
1.41      albertel 1095:     } elsif ($State eq "ChallengeReplied")  {
                   1096: 	# The echo was sent back, so we switch
                   1097: 	# to watching readability.
                   1098: 
                   1099: 	$Watcher->cb(\&LondReadable);
                   1100: 	$Watcher->poll("r");
                   1101:     } elsif ($State eq "RequestingVersion") {
                   1102: 	# Sending the peer a version request...
1.42      foxr     1103: 
1.41      albertel 1104:     } elsif ($State eq "ReadingVersionString") {
                   1105: 	# Transition to read since we have sent the
                   1106: 	# version command and now just need to read the
                   1107: 	# version string from the peer:
1.40      foxr     1108:       
1.41      albertel 1109: 	$Watcher->cb(\&LondReadable);
                   1110: 	$Watcher->poll("r");
1.40      foxr     1111:       
1.41      albertel 1112:     } elsif ($State eq "SetHost") {
                   1113: 	#  Setting the remote domain...
1.42      foxr     1114: 
1.41      albertel 1115:     } elsif ($State eq "HostSet") {
                   1116: 	# Back to readable to get the ok.
1.40      foxr     1117:       
1.41      albertel 1118: 	$Watcher->cb(\&LondReadable);
                   1119: 	$Watcher->poll("r");
1.40      foxr     1120:       
                   1121: 
1.41      albertel 1122:     } elsif ($State eq "RequestingKey")     {
                   1123: 	# At this time we're requesting the key.
                   1124: 	# again, this is essentially a no-op.
                   1125: 
                   1126:     } elsif ($State eq "ReceivingKey")      {
                   1127: 	# Now we need to wait for the key
                   1128: 	# to come back from the peer:
                   1129: 
                   1130: 	$Watcher->cb(\&LondReadable);
                   1131: 	$Watcher->poll("r");
                   1132: 
                   1133:     } elsif ($State eq "SendingRequest")    {
1.40      foxr     1134:  
1.41      albertel 1135: 	# At this time we are sending a request to the
1.1       foxr     1136: 	# peer... write the next chunk:
                   1137: 
1.41      albertel 1138: 
                   1139:     } elsif ($State eq "ReceivingReply")    {
                   1140: 	# The send has completed.  Wait for the
                   1141: 	# data to come in for a reply.
                   1142: 	Debug(8,"Writable sent request/receiving reply");
                   1143: 	$Watcher->cb(\&LondReadable);
                   1144: 	$Watcher->poll("r");
1.1       foxr     1145: 
1.41      albertel 1146:     } else {
                   1147: 	#  Control only passes here on an error: 
                   1148: 	#  the socket state does not match any
                   1149: 	#  of the known states... so an error
                   1150: 	#  must be logged.
1.1       foxr     1151: 
1.41      albertel 1152: 	&Debug(4, "Invalid socket state ".$State."\n");
                   1153:     }
1.1       foxr     1154:     
                   1155: }
1.6       foxr     1156: =pod
                   1157:     
                   1158: =cut
1.69      matthew  1159: 
1.6       foxr     1160: sub QueueDelayed {
1.8       foxr     1161:     Debug(3,"QueueDelayed called");
                   1162: 
1.6       foxr     1163:     my $path = "$perlvar{'lonSockDir'}/delayed";
1.8       foxr     1164: 
                   1165:     Debug(4, "Delayed path: ".$path);
1.6       foxr     1166:     opendir(DIRHANDLE, $path);
1.75    ! albertel 1167: 
        !          1168:     my @all_host_ids;
        !          1169:     my $host_iterator =   &LondConnection::GetHostIterator();
        !          1170:     while (!$host_iterator->end()) {
        !          1171: 	my ($host_id,$host_name) = @{$host_iterator->get()}[0,3];
        !          1172: 	if ($host_name eq $RemoteHost) {
        !          1173: 	    push(@all_host_ids, $host_id);
        !          1174: 	}
        !          1175: 	$host_iterator->next();
        !          1176:     }
        !          1177:     my $host_id_re = '(?:'.join('|',@all_host_ids).')';
        !          1178:     my @alldelayed = grep(/\.$host_id_re$/, readdir(DIRHANDLE));
1.6       foxr     1179:     closedir(DIRHANDLE);
1.75    ! albertel 1180:     foreach my $dfname (sort(@alldelayed)) {
        !          1181: 	my $reqfile = "$path/$dfname";
        !          1182: 	my ($host_id) = ($dfname =~ /\.([^.]*)$/);
        !          1183: 	Debug(4, "queueing ".$reqfile." for $host_id");
1.6       foxr     1184: 	my $Handle = IO::File->new($reqfile);
                   1185: 	my $cmd    = <$Handle>;
1.8       foxr     1186: 	chomp $cmd;		# There may or may not be a newline...
1.12      foxr     1187: 	$cmd = $cmd."\n";	# now for sure there's exactly one newline.
1.75    ! albertel 1188: 	my $Transaction = LondTransaction->new("sethost:$host_id:$cmd");
1.7       foxr     1189: 	$Transaction->SetDeferred($reqfile);
                   1190: 	QueueTransaction($Transaction);
1.6       foxr     1191:     }
                   1192:     
                   1193: }
1.1       foxr     1194: 
                   1195: =pod
1.3       albertel 1196: 
1.1       foxr     1197: =head2 MakeLondConnection
1.3       albertel 1198: 
                   1199: Create a new lond connection object, and start it towards its initial
                   1200: idleness.  Once idle, it becomes elligible to receive transactions
                   1201: from the work queue.  If the work queue is not empty when the
                   1202: connection is completed and becomes idle, it will dequeue an entry and
                   1203: start off on it.
                   1204: 
1.1       foxr     1205: =cut
1.3       albertel 1206: 
1.1       foxr     1207: sub MakeLondConnection {     
                   1208:     Debug(4,"MakeLondConnection to ".GetServerHost()." on port "
                   1209: 	  .GetServerPort());
                   1210: 
                   1211:     my $Connection = LondConnection->new(&GetServerHost(),
                   1212: 					 &GetServerPort());
                   1213: 
1.30      foxr     1214:     if($Connection eq undef) {	# Needs to be more robust later.
1.9       foxr     1215: 	Log("CRITICAL","Failed to make a connection with lond.");
1.10      foxr     1216: 	$ConnectionRetriesLeft--;
                   1217: 	return 0;		# Failure.
1.5       foxr     1218:     }  else {
1.22      foxr     1219: 
1.5       foxr     1220: 	# The connection needs to have writability 
                   1221: 	# monitored in order to send the init sequence
                   1222: 	# that starts the whole authentication/key
                   1223: 	# exchange underway.
                   1224: 	#
                   1225: 	my $Socket = $Connection->GetSocket();
1.30      foxr     1226: 	if($Socket eq undef) {
1.64      foxr     1227: 	    &child_exit(-1, "did not get a socket from the connection");
1.5       foxr     1228: 	} else {
                   1229: 	    &Debug(9,"MakeLondConnection got socket: ".$Socket);
                   1230: 	}
1.1       foxr     1231: 	
1.21      foxr     1232: 	$Connection->SetTimeoutCallback(\&SocketTimeout);
                   1233: 
1.23      foxr     1234: 	my $event = Event->io(fd       => $Socket,
1.5       foxr     1235: 			   poll     => 'w',
                   1236: 			   cb       => \&LondWritable,
1.8       foxr     1237: 			   data     => $Connection,
1.5       foxr     1238: 			   desc => 'Connection to lond server');
                   1239: 	$ActiveConnections{$Connection} = $event;
1.52      foxr     1240: 	if ($ConnectionCount == 0) {
                   1241: 	    &SetupTimer;	# Need to handle timeouts with connections...
                   1242: 	}
1.5       foxr     1243: 	$ConnectionCount++;
1.8       foxr     1244: 	Debug(4, "Connection count = ".$ConnectionCount);
1.6       foxr     1245: 	if($ConnectionCount == 1) { # First Connection:
                   1246: 	    QueueDelayed;
                   1247: 	}
1.9       foxr     1248: 	Log("SUCESS", "Created connection ".$ConnectionCount
                   1249: 	    ." to host ".GetServerHost());
1.54      foxr     1250: 	$LondConnecting = 1;	# Connection in progress.
1.10      foxr     1251: 	return 1;		# Return success.
1.1       foxr     1252:     }
                   1253:     
                   1254: }
1.3       albertel 1255: 
1.1       foxr     1256: =pod
1.3       albertel 1257: 
1.1       foxr     1258: =head2 StartRequest
1.3       albertel 1259: 
                   1260: Starts a lond request going on a specified lond connection.
                   1261: parameters are:
                   1262: 
                   1263: =item $Lond
                   1264: 
                   1265: Connection to the lond that will send the transaction and receive the
                   1266: reply.
                   1267: 
                   1268: =item $Client
                   1269: 
                   1270: Connection to the client that is making this request We got the
                   1271: request from this socket, and when the request has been relayed to
                   1272: lond and we get a reply back from lond it will get sent to this
                   1273: socket.
                   1274: 
                   1275: =item $Request
                   1276: 
                   1277: The text of the request to send.
                   1278: 
1.1       foxr     1279: =cut
                   1280: 
                   1281: sub StartRequest {
1.47      foxr     1282: 
                   1283:     my ($Lond, $Request) = @_;
1.1       foxr     1284:     
1.7       foxr     1285:     Debug(6, "StartRequest: ".$Request->getRequest());
1.1       foxr     1286: 
                   1287:     my $Socket = $Lond->GetSocket();
                   1288:     
1.7       foxr     1289:     $Request->Activate($Lond);
                   1290:     $ActiveTransactions{$Lond} = $Request;
1.1       foxr     1291: 
1.7       foxr     1292:     $Lond->InitiateTransaction($Request->getRequest());
1.23      foxr     1293:     my $event = Event->io(fd      => $Socket,
1.1       foxr     1294: 		       poll    => "w",
                   1295: 		       cb      => \&LondWritable,
                   1296: 		       data    => $Lond,
                   1297: 		       desc    => "lond transaction connection");
                   1298:     $ActiveConnections{$Lond} = $event;
                   1299:     Debug(8," Start Request made watcher data with ".$event->data."\n");
                   1300: }
                   1301: 
                   1302: =pod
1.3       albertel 1303: 
1.1       foxr     1304: =head2 QueueTransaction
1.3       albertel 1305: 
                   1306: If there is an idle lond connection, it is put to work doing this
                   1307: transaction.  Otherwise, the transaction is placed in the work queue.
                   1308: If placed in the work queue and the maximum number of connections has
                   1309: not yet been created, a new connection will be started.  Our goal is
                   1310: to eventually have a sufficient number of connections that the work
                   1311: queue will typically be empty.  parameters are:
                   1312: 
                   1313: =item Socket
                   1314: 
                   1315: open on the lonc client.
                   1316: 
                   1317: =item Request
                   1318: 
                   1319: data to send to the lond.
1.1       foxr     1320: 
                   1321: =cut
1.3       albertel 1322: 
1.1       foxr     1323: sub QueueTransaction {
                   1324: 
1.7       foxr     1325:     my $requestData   = shift;	# This is a LondTransaction.
                   1326:     my $cmd           = $requestData->getRequest();
                   1327: 
                   1328:     Debug(6,"QueueTransaction: ".$cmd);
1.1       foxr     1329: 
                   1330:     my $LondSocket    = $IdleConnections->pop();
                   1331:     if(!defined $LondSocket) {	# Need to queue request.
1.29      foxr     1332: 	Debug(5,"Must queue...");
1.1       foxr     1333: 	$WorkQueue->enqueue($requestData);
1.56      foxr     1334: 	Debug(5, "Queue Transaction startnew $ConnectionCount $LondConnecting");
                   1335: 	if(($ConnectionCount < $MaxConnectionCount)   && (! $LondConnecting)) {
                   1336: 
1.22      foxr     1337: 	    if($ConnectionRetriesLeft > 0) {
1.29      foxr     1338: 		Debug(5,"Starting additional lond connection");
1.56      foxr     1339: 		if(&MakeLondConnection() == 0) {
1.22      foxr     1340: 		    EmptyQueue();	# Fail transactions, can't make connection.
1.42      foxr     1341: 		    CloseAllLondConnections; # Should all be closed but...
1.22      foxr     1342: 		}
                   1343: 	    } else {
                   1344: 		ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
1.56      foxr     1345: 		$LondConnecting = 0;
1.22      foxr     1346: 		EmptyQueue();	# It's worse than that ... he's dead Jim.
1.42      foxr     1347: 		CloseAllLondConnections; # Should all be closed but..
1.17      foxr     1348: 	    }
1.1       foxr     1349: 	}
                   1350:     } else {			# Can start the request:
                   1351: 	Debug(8,"Can start...");
1.7       foxr     1352: 	StartRequest($LondSocket,  $requestData);
1.1       foxr     1353:     }
                   1354: }
                   1355: 
                   1356: #-------------------------- Lonc UNIX socket handling ---------------------
1.3       albertel 1357: 
1.1       foxr     1358: =pod
1.3       albertel 1359: 
1.1       foxr     1360: =head2 ClientRequest
1.3       albertel 1361: Callback that is called when data can be read from the UNIX domain
                   1362: socket connecting us with an apache server process.
1.1       foxr     1363: 
                   1364: =cut
                   1365: 
                   1366: sub ClientRequest {
                   1367:     Debug(6, "ClientRequest");
                   1368:     my $event   = shift;
                   1369:     my $watcher = $event->w;
                   1370:     my $socket  = $watcher->fd;
                   1371:     my $data    = $watcher->data;
                   1372:     my $thisread;
                   1373: 
                   1374:     Debug(9, "  Watcher named: ".$watcher->desc);
                   1375: 
                   1376:     my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
                   1377:     Debug(8, "rcv:  data length = ".length($thisread)
                   1378: 	  ." read =".$thisread);
1.29      foxr     1379:     unless (defined $rv  && length($thisread)) {
1.1       foxr     1380: 	 # Likely eof on socket.
                   1381: 	Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
                   1382: 	close($socket);
                   1383: 	$watcher->cancel();
                   1384: 	delete($ActiveClients{$socket});
1.10      foxr     1385: 	return;
1.1       foxr     1386:     }
                   1387:     Debug(8,"Data: ".$data." this read: ".$thisread);
                   1388:     $data = $data.$thisread;	# Append new data.
                   1389:     $watcher->data($data);
1.44      albertel 1390:     if($data =~ /\n$/) {	# Request entirely read.
1.10      foxr     1391: 	if($data eq "close_connection_exit\n") {
1.9       foxr     1392: 	    Log("CRITICAL",
                   1393: 		"Request Close Connection ... exiting");
                   1394: 	    CloseAllLondConnections();
                   1395: 	    exit;
                   1396: 	}
1.1       foxr     1397: 	Debug(8, "Complete transaction received: ".$data);
1.39      foxr     1398: 	if($LogTransactions) {
                   1399: 	    Log("SUCCESS", "Transaction: '$data'"); # Transaction has \n.
                   1400: 	}
1.8       foxr     1401: 	my $Transaction = LondTransaction->new($data);
1.7       foxr     1402: 	$Transaction->SetClient($socket);
                   1403: 	QueueTransaction($Transaction);
1.1       foxr     1404: 	$watcher->cancel();	# Done looking for input data.
                   1405:     }
                   1406: 
                   1407: }
                   1408: 
1.62      foxr     1409: #
                   1410: #     Accept a connection request for a client (lonc child) and
                   1411: #    start up an event watcher to keep an eye on input from that 
                   1412: #    Event.  This can be called both from NewClient and from
                   1413: #    ChildProcess if we are started in DieWhenIdle mode.
                   1414: # Parameters:
                   1415: #    $socket       - The listener socket.
                   1416: # Returns:
                   1417: #   NONE
                   1418: # Side Effects:
                   1419: #    An event is made to watch the accepted connection.
                   1420: #    Active clients hash is updated to reflect the new connection.
                   1421: #    The client connection count is incremented.
                   1422: #
                   1423: sub accept_client {
                   1424:     my ($socket) = @_;
                   1425: 
                   1426:     Debug(8, "Entering accept for lonc UNIX socket\n");
                   1427:     my $connection = $socket->accept();	# Accept the client connection.
                   1428:     Debug(8,"Connection request accepted from "
                   1429: 	  .GetPeername($connection, AF_UNIX));
                   1430: 
                   1431: 
                   1432:     my $description = sprintf("Connection to lonc client %d",
                   1433: 			      $ClientConnection);
                   1434:     Debug(9, "Creating event named: ".$description);
                   1435:     Event->io(cb      => \&ClientRequest,
                   1436: 	      poll    => 'r',
                   1437: 	      desc    => $description,
                   1438: 	      data    => "",
                   1439: 	      fd      => $connection);
                   1440:     $ActiveClients{$connection} = $ClientConnection;
                   1441:     $ClientConnection++;
                   1442: }
1.1       foxr     1443: 
                   1444: =pod
1.3       albertel 1445: 
1.1       foxr     1446: =head2  NewClient
1.3       albertel 1447: 
                   1448: Callback that is called when a connection is received on the unix
                   1449: socket for a new client of lonc.  The callback is parameterized by the
                   1450: event.. which is a-priori assumed to be an io event, and therefore has
                   1451: an fd member that is the Listener socket.  We Accept the connection
                   1452: and register a new event on the readability of that socket:
                   1453: 
1.1       foxr     1454: =cut
1.3       albertel 1455: 
1.1       foxr     1456: sub NewClient {
                   1457:     Debug(6, "NewClient");
                   1458:     my $event      = shift;		# Get the event parameters.
                   1459:     my $watcher    = $event->w; 
                   1460:     my $socket     = $watcher->fd;	# Get the event' socket.
                   1461: 
1.62      foxr     1462:     &accept_client($socket);
1.1       foxr     1463: }
1.3       albertel 1464: 
                   1465: =pod
                   1466: 
                   1467: =head2 GetLoncSocketPath
                   1468: 
                   1469: Returns the name of the UNIX socket on which to listen for client
                   1470: connections.
1.1       foxr     1471: 
1.58      foxr     1472: =head2 Parameters:
                   1473: 
                   1474:     host (optional)  - Name of the host socket to return.. defaults to
                   1475:                        the return from GetServerHost().
                   1476: 
1.1       foxr     1477: =cut
1.3       albertel 1478: 
1.1       foxr     1479: sub GetLoncSocketPath {
1.58      foxr     1480: 
                   1481:     my $host = GetServerHost();	# Default host.
                   1482:     if (@_) {
                   1483: 	($host)  = @_;		# Override if supplied.
                   1484:     }
                   1485:     return $UnixSocketDir."/".$host;
1.1       foxr     1486: }
                   1487: 
1.3       albertel 1488: =pod
                   1489: 
                   1490: =head2 GetServerHost
                   1491: 
                   1492: Returns the host whose lond we talk with.
                   1493: 
1.1       foxr     1494: =cut
1.3       albertel 1495: 
1.7       foxr     1496: sub GetServerHost {
1.1       foxr     1497:     return $RemoteHost;		# Setup by the fork.
                   1498: }
1.3       albertel 1499: 
                   1500: =pod
                   1501: 
                   1502: =head2 GetServerPort
                   1503: 
                   1504: Returns the lond port number.
                   1505: 
1.1       foxr     1506: =cut
1.3       albertel 1507: 
1.7       foxr     1508: sub GetServerPort {
1.1       foxr     1509:     return $perlvar{londPort};
                   1510: }
1.3       albertel 1511: 
                   1512: =pod
                   1513: 
                   1514: =head2 SetupLoncListener
                   1515: 
                   1516: Setup a lonc listener event.  The event is called when the socket
                   1517: becomes readable.. that corresponds to the receipt of a new
                   1518: connection.  The event handler established will accept the connection
                   1519: (creating a communcations channel), that int turn will establish
                   1520: another event handler to subess requests.
1.1       foxr     1521: 
1.58      foxr     1522: =head2  Parameters:
                   1523: 
                   1524:    host (optional)   Name of the host to set up a unix socket to.
                   1525: 
1.1       foxr     1526: =cut
1.3       albertel 1527: 
1.1       foxr     1528: sub SetupLoncListener {
                   1529: 
1.58      foxr     1530:     my $host       = GetServerHost(); # Default host.
                   1531:     if (@_) {
                   1532: 	($host)    = @_		# Override host with parameter.
                   1533:     }
                   1534: 
1.1       foxr     1535:     my $socket;
1.58      foxr     1536:     my $SocketName = GetLoncSocketPath($host);
1.1       foxr     1537:     unlink($SocketName);
1.7       foxr     1538:     unless ($socket =IO::Socket::UNIX->new(Local  => $SocketName,
1.55      albertel 1539: 					    Listen => 250, 
1.1       foxr     1540: 					    Type   => SOCK_STREAM)) {
1.64      foxr     1541: 	if($I_am_child) {
                   1542: 	    &child_exit(-1, "Failed to create a lonc listener socket");
                   1543: 	} else {
                   1544: 	    die "Failed to create a lonc listner socket";
                   1545: 	}
1.1       foxr     1546:     }
1.59      foxr     1547:     return $socket;
1.1       foxr     1548: }
                   1549: 
1.39      foxr     1550: #
                   1551: #   Toggle transaction logging.
                   1552: #  Implicit inputs:  
                   1553: #     LogTransactions
                   1554: #  Implicit Outputs:
                   1555: #     LogTransactions
                   1556: sub ToggleTransactionLogging {
                   1557:     print STDERR "Toggle transaction logging...\n";
                   1558:     if(!$LogTransactions) {
                   1559: 	$LogTransactions = 1;
                   1560:     } else {
                   1561: 	$LogTransactions = 0;
                   1562:     }
                   1563: 
                   1564: 
                   1565:     Log("SUCCESS", "Toggled transaction logging: $LogTransactions \n");
                   1566: }
                   1567: 
1.14      foxr     1568: =pod 
                   1569: 
                   1570: =head2 ChildStatus
                   1571:  
                   1572: Child USR1 signal handler to report the most recent status
                   1573: into the status file.
                   1574: 
1.22      foxr     1575: We also use this to reset the retries count in order to allow the
                   1576: client to retry connections with a previously dead server.
1.69      matthew  1577: 
1.14      foxr     1578: =cut
1.46      albertel 1579: 
1.14      foxr     1580: sub ChildStatus {
                   1581:     my $event = shift;
                   1582:     my $watcher = $event->w;
                   1583: 
                   1584:     Debug(2, "Reporting child status because : ".$watcher->data);
                   1585:     my $docdir = $perlvar{'lonDocRoot'};
1.67      albertel 1586:     
                   1587:     open(LOG,">>$docdir/lon-status/loncstatus.txt");
                   1588:     flock(LOG,LOCK_EX);
                   1589:     print LOG $$."\t".$RemoteHost."\t".$Status."\t".
1.14      foxr     1590: 	$RecentLogEntry."\n";
1.38      foxr     1591:     #
                   1592:     #  Write out information about each of the connections:
                   1593:     #
1.46      albertel 1594:     if ($DebugLevel > 2) {
1.67      albertel 1595: 	print LOG "Active connection statuses: \n";
1.46      albertel 1596: 	my $i = 1;
                   1597: 	print STDERR  "================================= Socket Status Dump:\n";
                   1598: 	foreach my $item (keys %ActiveConnections) {
                   1599: 	    my $Socket = $ActiveConnections{$item}->data;
                   1600: 	    my $state  = $Socket->GetState();
1.67      albertel 1601: 	    print LOG "Connection $i State: $state\n";
1.46      albertel 1602: 	    print STDERR "---------------------- Connection $i \n";
1.48      foxr     1603: 	    $Socket->Dump(-1);	# Ensure it gets dumped..
1.46      albertel 1604: 	    $i++;	
                   1605: 	}
1.38      foxr     1606:     }
1.67      albertel 1607:     flock(LOG,LOCK_UN);
                   1608:     close(LOG);
1.22      foxr     1609:     $ConnectionRetriesLeft = $ConnectionRetries;
1.70      albertel 1610:     UpdateStatus();
1.14      foxr     1611: }
                   1612: 
1.1       foxr     1613: =pod
1.3       albertel 1614: 
1.10      foxr     1615: =head2 SignalledToDeath
                   1616: 
                   1617: Called in response to a signal that causes a chid process to die.
                   1618: 
                   1619: =cut
                   1620: 
                   1621: 
                   1622: sub SignalledToDeath {
1.14      foxr     1623:     my $event  = shift;
                   1624:     my $watcher= $event->w;
                   1625: 
                   1626:     Debug(2,"Signalled to death! via ".$watcher->data);
1.17      foxr     1627:     my ($signal) = $watcher->data;
1.10      foxr     1628:     chomp($signal);
                   1629:     Log("CRITICAL", "Abnormal exit.  Child $$ for $RemoteHost "
                   1630: 	."died through "."\"$signal\"");
1.68      albertel 1631:     #LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
                   1632: #	    ."\"$signal\"");
1.12      foxr     1633:     exit 0;
1.10      foxr     1634: 
                   1635: }
1.16      foxr     1636: 
1.69      matthew  1637: =pod
                   1638: 
1.16      foxr     1639: =head2 ToggleDebug
                   1640: 
                   1641: This sub toggles trace debugging on and off.
                   1642: 
                   1643: =cut
                   1644: 
                   1645: sub ToggleDebug {
                   1646:     my $Current    = $DebugLevel;
                   1647:        $DebugLevel = $NextDebugLevel;
                   1648:        $NextDebugLevel = $Current;
                   1649: 
                   1650:     Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
                   1651: 
                   1652: }
                   1653: 
1.69      matthew  1654: =pod
                   1655: 
1.1       foxr     1656: =head2 ChildProcess
                   1657: 
                   1658: This sub implements a child process for a single lonc daemon.
1.61      foxr     1659: Optional parameter:
                   1660:    $socket  - if provided, this is a socket already open for listen
                   1661:               on the client socket. Otherwise, a new listen is set up.
1.1       foxr     1662: 
                   1663: =cut
                   1664: 
                   1665: sub ChildProcess {
1.62      foxr     1666:     #  If we are in DieWhenIdle mode, we've inherited all the
                   1667:     #  events of our parent and those have to be cancelled or else
                   1668:     #  all holy bloody chaos will result.. trust me, I already made
                   1669:     #  >that< mistake.
                   1670: 
                   1671:     my $host = GetServerHost();
                   1672:     foreach my $listener (keys %parent_dispatchers) {
                   1673: 	my $watcher = $parent_dispatchers{$listener};
                   1674: 	my $s       = $watcher->fd;
                   1675: 	if ($listener ne $host) { # Close everyone but me.
                   1676: 	    Debug(5, "Closing listen socket for $listener");
                   1677: 	    $s->close();
                   1678: 	}
                   1679: 	Debug(5, "Killing watcher for $listener");
                   1680: 
                   1681: 	$watcher->cancel();
1.65      foxr     1682: 	delete($parent_dispatchers{$listener});
1.62      foxr     1683: 
                   1684:     }
1.65      foxr     1685: 
                   1686:     #  kill off the parent's signal handlers too!  
                   1687:     #
                   1688: 
                   1689:     for my $handler (keys %parent_handlers) {
                   1690: 	my $watcher = $parent_handlers{$handler};
                   1691: 	$watcher->cancel();
                   1692: 	delete($parent_handlers{$handler});
                   1693:     }
                   1694: 
1.64      foxr     1695:     $I_am_child    = 1;		# Seems like in spite of it all I may still getting
                   1696:                                 # parent event dispatches.. flag I'm a child.
1.1       foxr     1697: 
                   1698: 
1.14      foxr     1699:     #
                   1700:     #  Signals must be handled by the Event framework...
1.61      foxr     1701:     #
1.14      foxr     1702: 
                   1703:     Event->signal(signal   => "QUIT",
                   1704: 		  cb       => \&SignalledToDeath,
                   1705: 		  data     => "QUIT");
                   1706:     Event->signal(signal   => "HUP",
                   1707: 		  cb       => \&ChildStatus,
                   1708: 		  data     => "HUP");
                   1709:     Event->signal(signal   => "USR1",
                   1710: 		  cb       => \&ChildStatus,
                   1711: 		  data     => "USR1");
1.39      foxr     1712:     Event->signal(signal   => "USR2",
                   1713: 		  cb       => \&ToggleTransactionLogging);
1.16      foxr     1714:     Event->signal(signal   => "INT",
                   1715: 		  cb       => \&ToggleDebug,
                   1716: 		  data     => "INT");
1.1       foxr     1717: 
1.62      foxr     1718:     #  Figure out if we got passed a socket or need to open one to listen for
                   1719:     #  client requests.
                   1720: 
1.61      foxr     1721:     my ($socket) = @_;
                   1722:     if (!$socket) {
                   1723: 
                   1724: 	$socket =  SetupLoncListener();
                   1725:     }
1.62      foxr     1726:     #  Establish an event to listen for client connection requests.
                   1727: 
                   1728: 
1.59      foxr     1729:     Event->io(cb   => \&NewClient,
                   1730: 	      poll => 'r',
                   1731: 	      desc => 'Lonc Listener Unix Socket',
                   1732: 	      fd   => $socket);
1.1       foxr     1733:     
                   1734:     $Event::Debuglevel = $DebugLevel;
                   1735:     
                   1736:     Debug(9, "Making initial lond connection for ".$RemoteHost);
                   1737: 
                   1738: # Setup the initial server connection:
                   1739:     
1.62      foxr     1740:      # &MakeLondConnection(); // let first work request do it.
1.10      foxr     1741: 
1.62      foxr     1742:     #  If We are in diwhenidle, need to accept the connection since the
                   1743:     #  event may  not fire.
                   1744: 
                   1745:     if ($DieWhenIdle) {
                   1746: 	&accept_client($socket);
                   1747:     }
1.5       foxr     1748: 
1.1       foxr     1749:     Debug(9,"Entering event loop");
                   1750:     my $ret = Event::loop();		#  Start the main event loop.
                   1751:     
                   1752:     
1.64      foxr     1753:     &child_exit (-1,"Main event loop exited!!!");
1.1       foxr     1754: }
                   1755: 
                   1756: #  Create a new child for host passed in:
                   1757: 
                   1758: sub CreateChild {
1.62      foxr     1759:     my ($host, $socket) = @_;
1.52      foxr     1760: 
1.12      foxr     1761:     my $sigset = POSIX::SigSet->new(SIGINT);
                   1762:     sigprocmask(SIG_BLOCK, $sigset);
1.1       foxr     1763:     $RemoteHost = $host;
1.9       foxr     1764:     Log("CRITICAL", "Forking server for ".$host);
1.23      foxr     1765:     my $pid          = fork;
1.1       foxr     1766:     if($pid) {			# Parent
1.17      foxr     1767: 	$RemoteHost = "Parent";
1.27      foxr     1768: 	$ChildHash{$pid} = $host;
1.26      foxr     1769: 	$HostToPid{$host}= $pid;
1.12      foxr     1770: 	sigprocmask(SIG_UNBLOCK, $sigset);
                   1771: 
1.1       foxr     1772:     } else {			# child.
1.5       foxr     1773: 	ShowStatus("Connected to ".$RemoteHost);
1.23      foxr     1774: 	$SIG{INT} = 'DEFAULT';
1.12      foxr     1775: 	sigprocmask(SIG_UNBLOCK, $sigset);
1.62      foxr     1776: 	if(defined $socket) {
                   1777: 	    &ChildProcess($socket);
                   1778: 	} else {
                   1779: 	    ChildProcess;		# Does not return.
                   1780: 	}
1.1       foxr     1781:     }
1.61      foxr     1782: }
1.1       foxr     1783: 
1.61      foxr     1784: # parent_client_connection:
                   1785: #    Event handler that processes client connections for the parent process.
                   1786: #    This sub is called when the parent is listening on a socket and
                   1787: #    a connection request arrives.  We must:
                   1788: #     Start a child process to accept the connection request.
                   1789: #     Kill our listen on the socket.
                   1790: # Parameter:
                   1791: #    event       - The event object that was created to monitor this socket.
                   1792: #                  event->w->fd is the socket.
                   1793: # Returns:
                   1794: #    NONE
                   1795: #
                   1796: sub parent_client_connection {
1.62      foxr     1797:     if ($I_am_child) {
                   1798: 	#  Should not get here, but seem to anyway:
                   1799: 	&Debug(5," Child caught parent client connection event!!");
                   1800: 	my ($event) = @_;
                   1801: 	my $watcher = $event->w;
                   1802: 	$watcher->cancel();	# Try to kill it off again!!
                   1803:     } else {
                   1804: 	&Debug(9, "parent_client_connection");
                   1805: 	my ($event)   = @_;
                   1806: 	my $watcher   = $event->w;
                   1807: 	my $socket    = $watcher->fd;
                   1808: 	
                   1809: 	# Lookup the host associated with this socket:
                   1810: 	
                   1811: 	my $host = $listening_to{$socket};
                   1812: 	
                   1813: 	# Start the child:
                   1814: 	
                   1815: 	
                   1816: 	
                   1817: 	&Debug(9,"Creating child for $host (parent_client_connection)");
                   1818: 	&CreateChild($host, $socket);
                   1819: 	
                   1820: 	# Clean up the listen since now the child takes over until it exits.
                   1821: 	
                   1822: 	$watcher->cancel();		# Nolonger listening to this event
                   1823: 	delete($listening_to{$socket});
                   1824: 	delete($parent_dispatchers{$host});
                   1825: 	$socket->close();
                   1826:     }
1.61      foxr     1827: }
                   1828: 
                   1829: # parent_listen:
                   1830: #    Opens a socket and starts a listen for the parent process on a client UNIX
                   1831: #    domain socket.
                   1832: #
                   1833: #    This involves:
                   1834: #       Creating a socket for listen.
                   1835: #       Removing any socket lock file
                   1836: #       Adding an event handler for this socket becoming readable
                   1837: #         To the parent's event dispatcher.
                   1838: # Parameters:
                   1839: #    loncapa_host    - LonCAPA cluster name of the host represented by the client
                   1840: #                      socket.
                   1841: # Returns:
                   1842: #    NONE
                   1843: #
                   1844: sub parent_listen {
                   1845:     my ($loncapa_host) = @_;
                   1846:     Debug(5, "parent_listen: $loncapa_host");
                   1847: 
                   1848:     my $socket    = &SetupLoncListener($loncapa_host);
1.62      foxr     1849:     $listening_to{$socket} = $loncapa_host;
1.61      foxr     1850:     if (!$socket) {
                   1851: 	die "Unable to create a listen socket for $loncapa_host";
                   1852:     }
                   1853:     
1.62      foxr     1854:     my $lock_file = &GetLoncSocketPath($loncapa_host).".lock";
1.61      foxr     1855:     unlink($lock_file);		# No problem if it doesn't exist yet [startup e.g.]
                   1856: 
1.62      foxr     1857:     my $watcher = Event->io(cb    => \&parent_client_connection,
1.61      foxr     1858: 	      poll  => 'r',
1.62      foxr     1859: 	      desc  => "Parent listener unix socket ($loncapa_host)",
1.61      foxr     1860: 	      fd    => $socket);
1.62      foxr     1861:     $parent_dispatchers{$loncapa_host} = $watcher;
1.61      foxr     1862: 
                   1863: }
                   1864: 
                   1865: 
                   1866: # listen_on_all_unix_sockets:
                   1867: #    This sub initiates a listen on all unix domain lonc client sockets.
                   1868: #    This will be called in the case where we are trimming idle processes.
                   1869: #    When idle processes are trimmed, loncnew starts up with no children,
                   1870: #    and only spawns off children when a connection request occurs on the
                   1871: #    client unix socket.  The spawned child continues to run until it has
                   1872: #    been idle a while at which point it eventually exits and once more
                   1873: #    the parent picks up the listen.
                   1874: #
                   1875: #  Parameters:
                   1876: #      NONE
                   1877: #  Implicit Inputs:
                   1878: #    The configuration file that has been read in by LondConnection.
                   1879: #  Returns:
                   1880: #     NONE
                   1881: #
                   1882: sub listen_on_all_unix_sockets {
                   1883:     Debug(5, "listen_on_all_unix_sockets");
                   1884:     my $host_iterator      =   &LondConnection::GetHostIterator();
                   1885:     while (!$host_iterator->end()) {
                   1886: 	my $host_entry_ref =   $host_iterator->get();
1.74      albertel 1887: 	my $host_name      = $host_entry_ref->[3];
1.61      foxr     1888: 	Debug(9, "Listen for $host_name");
                   1889: 	&parent_listen($host_name);
                   1890: 	$host_iterator->next();
                   1891:     }
1.1       foxr     1892: }
1.61      foxr     1893: 
1.63      foxr     1894: #   server_died is called whenever a child process exits.
                   1895: #   Since this is dispatched via a signal, we must process all
                   1896: #   dead children until there are no more left.  The action
                   1897: #   is to:
                   1898: #      - Remove the child from the bookeeping hashes
                   1899: #      - Re-establish a listen on the unix domain socket associated
                   1900: #        with that host.
                   1901: # Parameters:
                   1902: #    The event, but we don't actually care about it.
                   1903: sub server_died {
                   1904:     &Debug(9, "server_died called...");
                   1905:     
                   1906:     while(1) {			# Loop until waitpid nowait fails.
                   1907: 	my $pid = waitpid(-1, WNOHANG);
                   1908: 	if($pid <= 0) {
                   1909: 	    return;		# Nothing left to wait for.
                   1910: 	}
                   1911: 	# need the host to restart:
                   1912: 
                   1913: 	my $host = $ChildHash{$pid};
                   1914: 	if($host) {		# It's for real...
                   1915: 	    &Debug(9, "Caught sigchild for $host");
                   1916: 	    delete($ChildHash{$pid});
                   1917: 	    delete($HostToPid{$host});
                   1918: 	    &parent_listen($host);
                   1919: 
                   1920: 	} else {
                   1921: 	    &Debug(5, "Caught sigchild for pid not in hosts hash: $pid");
                   1922: 	}
                   1923:     }
                   1924: 
                   1925: }
                   1926: 
1.1       foxr     1927: #
                   1928: #  Parent process logic pass 1:
                   1929: #   For each entry in the hosts table, we will
                   1930: #  fork off an instance of ChildProcess to service the transactions
                   1931: #  to that host.  Each pid will be entered in a global hash
                   1932: #  with the value of the key, the host.
                   1933: #  The parent will then enter a loop to wait for process exits.
                   1934: #  Each exit gets logged and the child gets restarted.
                   1935: #
                   1936: 
1.5       foxr     1937: #
                   1938: #   Fork and start in new session so hang-up isn't going to 
                   1939: #   happen without intent.
                   1940: #
                   1941: 
                   1942: 
1.6       foxr     1943: 
                   1944: 
1.8       foxr     1945: 
1.6       foxr     1946: 
                   1947: ShowStatus("Forming new session");
                   1948: my $childpid = fork;
                   1949: if ($childpid != 0) {
                   1950:     sleep 4;			# Give child a chacne to break to
                   1951:     exit 0;			# a new sesion.
                   1952: }
1.8       foxr     1953: #
                   1954: #   Write my pid into the pid file so I can be located
                   1955: #
                   1956: 
                   1957: ShowStatus("Parent writing pid file:");
1.23      foxr     1958: my $execdir = $perlvar{'lonDaemons'};
1.8       foxr     1959: open (PIDSAVE, ">$execdir/logs/lonc.pid");
                   1960: print PIDSAVE "$$\n";
                   1961: close(PIDSAVE);
1.6       foxr     1962: 
1.17      foxr     1963: 
                   1964: 
1.6       foxr     1965: if (POSIX::setsid() < 0) {
                   1966:     print "Could not create new session\n";
                   1967:     exit -1;
                   1968: }
1.5       foxr     1969: 
                   1970: ShowStatus("Forking node servers");
                   1971: 
1.9       foxr     1972: Log("CRITICAL", "--------------- Starting children ---------------");
                   1973: 
1.31      foxr     1974: LondConnection::ReadConfig;               # Read standard config files.
1.1       foxr     1975: my $HostIterator = LondConnection::GetHostIterator;
                   1976: 
1.60      foxr     1977: if ($DieWhenIdle) {
1.61      foxr     1978:     $RemoteHost = "[parent]";
                   1979:     &listen_on_all_unix_sockets();
1.60      foxr     1980: } else {
                   1981:     
                   1982:     while (! $HostIterator->end()) {
                   1983: 	
                   1984: 	my $hostentryref = $HostIterator->get();
                   1985: 	CreateChild($hostentryref->[0]);
                   1986: 	$HostHash{$hostentryref->[0]} = $hostentryref->[4];
                   1987: 	$HostIterator->next();
                   1988:     }
1.1       foxr     1989: }
1.60      foxr     1990: 
1.12      foxr     1991: $RemoteHost = "Parent Server";
1.1       foxr     1992: 
                   1993: # Maintain the population:
1.5       foxr     1994: 
                   1995: ShowStatus("Parent keeping the flock");
1.1       foxr     1996: 
1.12      foxr     1997: 
1.60      foxr     1998: if ($DieWhenIdle) {
1.63      foxr     1999:     # We need to setup a SIGChild event to handle the exit (natural or otherwise)
                   2000:     # of the children.
                   2001: 
                   2002:     Event->signal(cb       => \&server_died,
                   2003: 		   desc     => "Child exit handler",
                   2004: 		   signal   => "CHLD");
                   2005: 
                   2006: 
1.65      foxr     2007:     # Set up all the other signals we set up.  We'll vector them off to the
                   2008:     # same subs as we would for DieWhenIdle false and, if necessary, conditionalize
                   2009:     # the code there.
                   2010: 
                   2011:     $parent_handlers{INT} = Event->signal(cb       => \&Terminate,
                   2012: 					  desc     => "Parent INT handler",
                   2013: 					  signal   => "INT");
                   2014:     $parent_handlers{TERM} = Event->signal(cb       => \&Terminate,
                   2015: 					   desc     => "Parent TERM handler",
                   2016: 					   signal   => "TERM");
                   2017:     $parent_handlers{HUP}  = Event->signal(cb       => \&Restart,
                   2018: 					   desc     => "Parent HUP handler.",
                   2019: 					   signal   => "HUP");
                   2020:     $parent_handlers{USR1} = Event->signal(cb       => \&CheckKids,
                   2021: 					   desc     => "Parent USR1 handler",
                   2022: 					   signal   => "USR1");
                   2023:     $parent_handlers{USR2} = Event->signal(cb       => \&UpdateKids,
                   2024: 					   desc     => "Parent USR2 handler.",
                   2025: 					   signal   => "USR2");
                   2026:     
                   2027:     #  Start procdesing events.
                   2028: 
1.61      foxr     2029:     $Event::DebugLevel = $DebugLevel;
                   2030:     Debug(9, "Parent entering event loop");
                   2031:     my $ret = Event::loop();
                   2032:     die "Main Event loop exited: $ret";
                   2033: 
                   2034: 
1.60      foxr     2035: } else {
1.61      foxr     2036:     #
                   2037:     #   Set up parent signals:
                   2038:     #
1.60      foxr     2039:     
                   2040:     $SIG{INT}  = \&Terminate;
                   2041:     $SIG{TERM} = \&Terminate; 
                   2042:     $SIG{HUP}  = \&Restart;
                   2043:     $SIG{USR1} = \&CheckKids; 
                   2044:     $SIG{USR2} = \&UpdateKids;	# LonManage update request.
                   2045:     
                   2046:     while(1) {
                   2047: 	my $deadchild = wait();
                   2048: 	if(exists $ChildHash{$deadchild}) {	# need to restart.
                   2049: 	    my $deadhost = $ChildHash{$deadchild};
                   2050: 	    delete($HostToPid{$deadhost});
                   2051: 	    delete($ChildHash{$deadchild});
                   2052: 	    Log("WARNING","Lost child pid= ".$deadchild.
                   2053: 		"Connected to host ".$deadhost);
                   2054: 	    Log("INFO", "Restarting child procesing ".$deadhost);
                   2055: 	    CreateChild($deadhost);
                   2056: 	}
1.1       foxr     2057:     }
1.13      foxr     2058: }
                   2059: 
1.14      foxr     2060: 
                   2061: =pod
                   2062: 
                   2063: =head1 CheckKids
                   2064: 
                   2065:   Since kids do not die as easily in this implementation
                   2066: as the previous one, there  is no need to restart the
                   2067: dead ones (all dead kids get restarted when they die!!)
                   2068: The only thing this function does is to pass USR1 to the
                   2069: kids so that they report their status.
                   2070: 
                   2071: =cut
                   2072: 
                   2073: sub CheckKids {
                   2074:     Debug(2, "Checking status of children");
                   2075:     my $docdir = $perlvar{'lonDocRoot'};
                   2076:     my $fh = IO::File->new(">$docdir/lon-status/loncstatus.txt");
                   2077:     my $now=time;
                   2078:     my $local=localtime($now);
                   2079:     print $fh "LONC status $local - parent $$ \n\n";
1.65      foxr     2080:     foreach my $host (keys %parent_dispatchers) {
                   2081: 	print $fh "LONC Parent process listening for $host\n";
                   2082:     }
1.23      foxr     2083:     foreach my $pid (keys %ChildHash) {
1.14      foxr     2084: 	Debug(2, "Sending USR1 -> $pid");
                   2085: 	kill 'USR1' => $pid;	# Tell Child to report status.
                   2086:     }
1.65      foxr     2087: 
1.14      foxr     2088: }
1.24      foxr     2089: 
                   2090: =pod
                   2091: 
                   2092: =head1  UpdateKids
                   2093: 
1.25      foxr     2094: parent's SIGUSR2 handler.  This handler:
1.24      foxr     2095: 
                   2096: =item
                   2097: 
                   2098: Rereads the hosts file.
                   2099: 
                   2100: =item
                   2101:  
                   2102: Kills off (via sigint) children for hosts that have disappeared.
                   2103: 
                   2104: =item
                   2105: 
1.27      foxr     2106: QUITs  children for hosts that already exist (this just forces a status display
1.24      foxr     2107: and resets the connection retry count for that host.
                   2108: 
                   2109: =item
                   2110: 
                   2111: Starts new children for hosts that have been added to the hosts.tab file since
                   2112: the start of the master program and maintains them.
                   2113: 
                   2114: =cut
                   2115: 
                   2116: sub UpdateKids {
1.27      foxr     2117: 
1.25      foxr     2118:     Log("INFO", "Updating connections via SIGUSR2");
1.27      foxr     2119: 
1.65      foxr     2120:     #  I'm not sure what I was thinking in the first implementation.
                   2121:     # someone will have to work hard to convince me the effect is any
                   2122:     # different than Restart, especially now that we don't start up 
                   2123:     # per host servers automatically, may as well just restart.
                   2124:     # The down side is transactions that are in flight will get timed out
                   2125:     # (lost unless they are critical).
1.27      foxr     2126: 
1.65      foxr     2127:     &Restart();
1.27      foxr     2128: 
1.24      foxr     2129: }
                   2130: 
1.14      foxr     2131: 
1.13      foxr     2132: =pod
                   2133: 
                   2134: =head1 Restart
                   2135: 
                   2136: Signal handler for HUP... all children are killed and
                   2137: we self restart.  This is an el-cheapo way to re read
                   2138: the config file.
                   2139: 
                   2140: =cut
                   2141: 
                   2142: sub Restart {
1.23      foxr     2143:     &KillThemAll;		# First kill all the children.
1.13      foxr     2144:     Log("CRITICAL", "Restarting");
                   2145:     my $execdir = $perlvar{'lonDaemons'};
                   2146:     unlink("$execdir/logs/lonc.pid");
1.65      foxr     2147:     exec("$executable");
1.10      foxr     2148: }
1.12      foxr     2149: 
                   2150: =pod
                   2151: 
                   2152: =head1 KillThemAll
                   2153: 
                   2154: Signal handler that kills all children by sending them a 
1.17      foxr     2155: SIGHUP.  Responds to sigint and sigterm.
1.12      foxr     2156: 
                   2157: =cut
                   2158: 
1.10      foxr     2159: sub KillThemAll {
1.12      foxr     2160:     Debug(2, "Kill them all!!");
                   2161:     local($SIG{CHLD}) = 'IGNORE';      # Our children >will< die.
1.23      foxr     2162:     foreach my $pid (keys %ChildHash) {
1.12      foxr     2163: 	my $serving = $ChildHash{$pid};
1.52      foxr     2164: 	ShowStatus("Nicely Killing lonc for $serving pid = $pid");
                   2165: 	Log("CRITICAL", "Nicely Killing lonc for $serving pid = $pid");
1.17      foxr     2166: 	kill 'QUIT' => $pid;
1.12      foxr     2167:     }
1.52      foxr     2168: 
1.17      foxr     2169: 
1.1       foxr     2170: }
1.12      foxr     2171: 
1.52      foxr     2172: 
                   2173: #
                   2174: #  Kill all children via KILL.  Just in case the
                   2175: #  first shot didn't get them.
                   2176: 
                   2177: sub really_kill_them_all_dammit
                   2178: {
                   2179:     Debug(2, "Kill them all Dammit");
                   2180:     local($SIG{CHLD} = 'IGNORE'); # In case some purist reenabled them.
                   2181:     foreach my $pid (keys %ChildHash) {
                   2182: 	my $serving = $ChildHash{$pid};
                   2183: 	&ShowStatus("Nastily killing lonc for $serving pid = $pid");
                   2184: 	Log("CRITICAL", "Nastily killing lonc for $serving pid = $pid");
                   2185: 	kill 'KILL' => $pid;
                   2186: 	delete($ChildHash{$pid});
                   2187: 	my $execdir = $perlvar{'lonDaemons'};
                   2188: 	unlink("$execdir/logs/lonc.pid");
                   2189:     }
                   2190: }
1.69      matthew  2191: 
1.14      foxr     2192: =pod
                   2193: 
                   2194: =head1 Terminate
                   2195:  
                   2196: Terminate the system.
                   2197: 
                   2198: =cut
                   2199: 
                   2200: sub Terminate {
1.52      foxr     2201:     &Log("CRITICAL", "Asked to kill children.. first be nice...");
                   2202:     &KillThemAll;
                   2203:     #
                   2204:     #  By now they really should all be dead.. but just in case 
                   2205:     #  send them all SIGKILL's after a bit of waiting:
                   2206: 
                   2207:     sleep(4);
                   2208:     &Log("CRITICAL", "Now kill children nasty");
                   2209:     &really_kill_them_all_dammit;
1.17      foxr     2210:     Log("CRITICAL","Master process exiting");
                   2211:     exit 0;
1.14      foxr     2212: 
                   2213: }
1.12      foxr     2214: =pod
1.1       foxr     2215: 
                   2216: =head1 Theory
1.3       albertel 2217: 
                   2218: The event class is used to build this as a single process with an
                   2219: event driven model.  The following events are handled:
1.1       foxr     2220: 
                   2221: =item UNIX Socket connection Received
                   2222: 
                   2223: =item Request data arrives on UNIX data transfer socket.
                   2224: 
                   2225: =item lond connection becomes writable.
                   2226: 
                   2227: =item timer fires at 1 second intervals.
                   2228: 
                   2229: All sockets are run in non-blocking mode.  Timeouts managed by the timer
                   2230: handler prevents hung connections.
                   2231: 
                   2232: Key data structures:
                   2233: 
1.3       albertel 2234: =item RequestQueue
                   2235: 
                   2236: A queue of requests received from UNIX sockets that are
                   2237: waiting for a chance to be forwarded on a lond connection socket.
                   2238: 
                   2239: =item ActiveConnections
                   2240: 
                   2241: A hash of lond connections that have transactions in process that are
                   2242: available to be timed out.
                   2243: 
                   2244: =item ActiveTransactions
                   2245: 
                   2246: A hash indexed by lond connections that contain the client reply
                   2247: socket for each connection that has an active transaction on it.
                   2248: 
                   2249: =item IdleConnections
                   2250: 
                   2251: A hash of lond connections that have no work to do.  These connections
                   2252: can be closed if they are idle for a long enough time.
1.1       foxr     2253: 
                   2254: =cut

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