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Diff for /loncom/loncnew between versions 1.3 and 1.34

version 1.3, 2003/04/18 03:10:36 version 1.34, 2003/12/11 23:18:37
Line 7 Line 7
 # Copyright Michigan State University Board of Trustees  # Copyright Michigan State University Board of Trustees
 #  #
 # This file is part of the LearningOnline Network with CAPA (LON-CAPA).  # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
 #  ## LON-CAPA is free software; you can redistribute it and/or modify
 # LON-CAPA is free software; you can redistribute it and/or modify  
 # it under the terms of the GNU General Public License as published by  # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 2 of the License, or  # the Free Software Foundation; either version 2 of the License, or
 # (at your option) any later version.  # (at your option) any later version.
Line 27 Line 26
 # http://www.lon-capa.org/  # http://www.lon-capa.org/
 #  #
 #  #
 # new lonc handles n requestors spread out bver m connections to londs.  # new lonc handles n request out bver m connections to londs.
 # This module is based on the Event class.  # This module is based on the Event class.
 #   Development iterations:  #   Development iterations:
 #    - Setup basic event loop.   (done)  #    - Setup basic event loop.   (done)
 #    - Add timer dispatch.       (done)  #    - Add timer dispatch.       (done)
 #    - Add ability to accept lonc UNIX domain sockets.  (done)  #    - Add ability to accept lonc UNIX domain sockets.  (done)
 #    - Add ability to create/negotiate lond connections (done).  #    - Add ability to create/negotiate lond connections (done).
 #    - Add general logic for dispatching requests and timeouts.  #    - Add general logic for dispatching requests and timeouts. (done).
 #    - Add support for the lonc/lond requests.  #    - Add support for the lonc/lond requests.          (done).
 #    - Add logging/status monitoring.  #    - Add logging/status monitoring.
 #    - Add Signal handling - HUP restarts. USR1 status report.  #    - Add Signal handling - HUP restarts. USR1 status report.
 #    - Add Configuration file I/O  #    - Add Configuration file I/O                       (done).
 #    - Add Pending request processing on startup.  
 #    - Add management/status request interface.  #    - Add management/status request interface.
   #    - Add deferred request capability.                  (done)
   #    - Detect transmission timeouts.
   #
   
   use strict;
 use lib "/home/httpd/lib/perl/";  use lib "/home/httpd/lib/perl/";
 use lib "/home/foxr/newloncapa/types";  
 use Event qw(:DEFAULT );  use Event qw(:DEFAULT );
 use POSIX qw(:signal_h);  use POSIX qw(:signal_h);
   use POSIX;
 use IO::Socket;  use IO::Socket;
 use IO::Socket::INET;  use IO::Socket::INET;
 use IO::Socket::UNIX;  use IO::Socket::UNIX;
   use IO::File;
   use IO::Handle;
 use Socket;  use Socket;
 use Crypt::IDEA;  use Crypt::IDEA;
 use LONCAPA::Queue;  use LONCAPA::Queue;
 use LONCAPA::Stack;  use LONCAPA::Stack;
 use LONCAPA::LondConnection;  use LONCAPA::LondConnection;
   use LONCAPA::LondTransaction;
 use LONCAPA::Configuration;  use LONCAPA::Configuration;
 use LONCAPA::HashIterator;  use LONCAPA::HashIterator;
   
 print "Loncnew starting\n";  
   
 #  #
 #   Disable all signals we might receive from outside for now.  #   Disable all signals we might receive from outside for now.
 #  #
 $SIG{QUIT}  = IGNORE;  
 $SIG{HUP}   = IGNORE;  
 $SIG{USR1}  = IGNORE;  
 $SIG{INT}   = IGNORE;  
 $SIG{CHLD}  = IGNORE;  
 $SIG{__DIE__}  = IGNORE;  
   
   
 # Read the httpd configuration file to get perl variables  # Read the httpd configuration file to get perl variables
Line 80  my %perlvar    = %{$perlvarref}; Line 78  my %perlvar    = %{$perlvarref};
 #  parent and shared variables.  #  parent and shared variables.
   
 my %ChildHash; # by pid -> host.  my %ChildHash; # by pid -> host.
   my %HostToPid; # By host -> pid.
   my %HostHash; # by loncapaname -> IP.
   
   
 my $MaxConnectionCount = 5; # Will get from config later.  my $MaxConnectionCount = 10; # Will get from config later.
 my $ClientConnection = 0; # Uniquifier for client events.  my $ClientConnection = 0; # Uniquifier for client events.
   
 my $DebugLevel = 5;  my $DebugLevel = 0;
   my $NextDebugLevel= 2; # So Sigint can toggle this.
 my $IdleTimeout= 3600; # Wait an hour before pruning connections.  my $IdleTimeout= 3600; # Wait an hour before pruning connections.
   
 #  #
 #  The variables below are only used by the child processes.  #  The variables below are only used by the child processes.
 #  #
 my $RemoteHost; # Name of host child is talking to.  my $RemoteHost; # Name of host child is talking to.
 my $UnixSocketDir= "/home/httpd/sockets";   my $UnixSocketDir= $perlvar{'lonSockDir'};
 my $IdleConnections = Stack->new(); # Set of idle connections  my $IdleConnections = Stack->new(); # Set of idle connections
 my %ActiveConnections; # Connections to the remote lond.  my %ActiveConnections; # Connections to the remote lond.
 my %ActiveTransactions; # Transactions in flight.  my %ActiveTransactions; # LondTransactions in flight.
 my %ActiveClients; # Serial numbers of active clients by socket.  my %ActiveClients; # Serial numbers of active clients by socket.
 my $WorkQueue       = Queue->new(); # Queue of pending transactions.  my $WorkQueue       = Queue->new(); # Queue of pending transactions.
 my $ClientQueue     = Queue->new(); # Queue of clients causing xactinos.  
 my $ConnectionCount = 0;  my $ConnectionCount = 0;
   my $IdleSeconds     = 0; # Number of seconds idle.
   my $Status          = ""; # Current status string.
   my $RecentLogEntry  = "";
   my $ConnectionRetries=2; # Number of connection retries allowed.
   my $ConnectionRetriesLeft=2; # Number of connection retries remaining.
   
 #  #
   #   The hash below gives the HTML format for log messages
   #   given a severity.
   #    
   my %LogFormats;
   
   $LogFormats{"CRITICAL"} = "<font color=red>CRITICAL: %s</font>";
   $LogFormats{"SUCCESS"}  = "<font color=green>SUCCESS: %s</font>";
   $LogFormats{"INFO"}     = "<font color=yellow>INFO: %s</font>";
   $LogFormats{"WARNING"}  = "<font color=blue>WARNING: %s</font>";
   $LogFormats{"DEFAULT"}  = " %s ";
   
   
   
   =pod
   
   =head2 LogPerm
   
   Makes an entry into the permanent log file.
   
   =cut
   sub LogPerm {
       my $message=shift;
       my $execdir=$perlvar{'lonDaemons'};
       my $now=time;
       my $local=localtime($now);
       my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
       print $fh "$now:$message:$local\n";
   }
   
   =pod
   
   =head2 Log
   
   Logs a message to the log file.
   Parameters:
   
   =item severity
   
   One of CRITICAL, WARNING, INFO, SUCCESS used to select the
   format string used to format the message.  if the severity is
   not a defined severity the Default format string is used.
   
   =item message
   
   The base message.  In addtion to the format string, the message
   will be appended to a string containing the name of our remote
   host and the time will be formatted into the message.
   
   =cut
   
   sub Log {
       my $severity = shift;
       my $message  = shift;
      
       if(!$LogFormats{$severity}) {
    $severity = "DEFAULT";
       }
   
       my $format = $LogFormats{$severity};
       
       #  Put the window dressing in in front of the message format:
   
       my $now   = time;
       my $local = localtime($now);
       my $finalformat = "$local ($$) [$RemoteHost] [$Status] ";
       my $finalformat = $finalformat.$format."\n";
   
       # open the file and put the result.
   
       my $execdir = $perlvar{'lonDaemons'};
       my $fh      = IO::File->new(">>$execdir/logs/lonc.log");
       my $msg = sprintf($finalformat, $message);
       $RecentLogEntry = $msg;
       print $fh $msg;
       
       
   }
   
   
 =pod  =pod
   
Line 120  sub GetPeername { Line 202  sub GetPeername {
     my $peerip;      my $peerip;
     if($AdrFamily == AF_INET) {      if($AdrFamily == AF_INET) {
  ($peerport, $peerip) = sockaddr_in($peer);   ($peerport, $peerip) = sockaddr_in($peer);
  my $peername    = gethostbyaddr($iaddr, $AdrFamily);   my $peername    = gethostbyaddr($peerip, $AdrFamily);
  return $peername;   return $peername;
     } elsif ($AdrFamily == AF_UNIX) {      } elsif ($AdrFamily == AF_UNIX) {
  my $peerfile;   my $peerfile;
Line 141  sub Debug { Line 223  sub Debug {
     my $level   = shift;      my $level   = shift;
     my $message = shift;      my $message = shift;
     if ($level <= $DebugLevel) {      if ($level <= $DebugLevel) {
  print $message." host = ".$RemoteHost."\n";   Log("INFO", "-Debug- $message host = $RemoteHost");
     }      }
 }  }
   
Line 155  sub SocketDump { Line 237  sub SocketDump {
   
 =pod  =pod
   
   =head2 ShowStatus
   
    Place some text as our pid status.
    and as what we return in a SIGUSR1
   
   =cut
   sub ShowStatus {
       my $state = shift;
       my $now = time;
       my $local = localtime($now);
       $Status   = $local.": ".$state;
       $0='lonc: '.$state.' '.$local;
   }
   
   =pod
   
   =head 2 SocketTimeout
   
       Called when an action on the socket times out.  The socket is 
      destroyed and any active transaction is failed.
   
   
   =cut
   sub SocketTimeout {
       my $Socket = shift;
       
       KillSocket($Socket); # A transaction timeout also counts as
                                   # a connection failure:
       $ConnectionRetriesLeft--;
   }
   
   =pod
   
 =head2 Tick  =head2 Tick
   
 Invoked  each timer tick.  Invoked  each timer tick.
   
 =cut  =cut
   
   
 sub Tick {  sub Tick {
     my $client;      my $client;
     Debug(6, "Tick");      if($ConnectionRetriesLeft > 0) {
     Debug(6, "    Current connection count: ".$ConnectionCount);   ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
     foreach $client (keys %ActiveClients) {     ." Retries remaining: ".$ConnectionRetriesLeft);
  Debug(7, "    Have client:  with id: ".$ActiveClients{$client});      } else {
    ShowStatus(GetServerHost()." >> DEAD <<");
       }
       # Is it time to prune connection count:
   
   
       if($IdleConnections->Count()  && 
          ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
    $IdleSeconds++;
    if($IdleSeconds > $IdleTimeout) { # Prune a connection...
       my $Socket = $IdleConnections->pop();
       KillSocket($Socket);
    }
       } else {
    $IdleSeconds = 0; # Reset idle count if not idle.
       }
       #
       #  For each inflight transaction, tick down its timeout counter.
       #
       foreach my $item (keys %ActiveTransactions) {
    my $Socket = $ActiveTransactions{$item}->getServer();
    $Socket->Tick();
       }
       foreach my $item (keys %ActiveConnections) {
    my $State = $ActiveConnections{$item}->data->GetState();
    if ($State ne 'Idle' && $State ne 'SendingRequest' &&
       $State ne 'ReceivingReply') {
       Debug(5,"Ticking Socket $State $item");
       $ActiveConnections{$item}->data->Tick();
    }
       }
       # Do we have work in the queue, but no connections to service them?
       # If so, try to make some new connections to get things going again.
       #
       
       my $Requests = $WorkQueue->Count();
       if (($ConnectionCount == 0)  && ($Requests > 0)) { 
    if ($ConnectionRetriesLeft > 0) {
       my $Connections = ($Requests <= $MaxConnectionCount) ?
    $Requests : $MaxConnectionCount;
       Debug(5,"Work but no connections, start ".$Connections." of them");
       my $successCount = 0;
       for (my $i =0; $i < $Connections; $i++) {
    $successCount += MakeLondConnection();
       }
       if($successCount == 0) { # All connections failed:
    Debug(5,"Work in queue failed to make any connectiouns\n");
    EmptyQueue(); # Fail pending transactions with con_lost.
       }
    } else {
       ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
       Debug(5,"Work in queue, but gave up on connections..flushing\n");
       EmptyQueue(); # Connections can't be established.
    }
          
     }      }
 }  }
   
Line 188  Trigger disconnections of idle sockets. Line 358  Trigger disconnections of idle sockets.
   
 sub SetupTimer {  sub SetupTimer {
     Debug(6, "SetupTimer");      Debug(6, "SetupTimer");
     Event->timer(interval => 1, debug => 1, cb => \&Tick );      Event->timer(interval => 1, cb => \&Tick );
 }  }
   
 =pod  =pod
Line 208  long enough, it will be shut down and re Line 378  long enough, it will be shut down and re
   
 sub ServerToIdle {  sub ServerToIdle {
     my $Socket   = shift; # Get the socket.      my $Socket   = shift; # Get the socket.
       delete($ActiveTransactions{$Socket}); # Server has no transaction
   
     &Debug(6, "Server to idle");      &Debug(5, "Server to idle");
   
     #  If there's work to do, start the transaction:      #  If there's work to do, start the transaction:
   
     $reqdata = $WorkQueue->dequeue();      my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
     Debug(9, "Queue gave request data: ".$reqdata);      if ($reqdata ne undef)  {
     unless($reqdata eq undef)  {   Debug(5, "Queue gave request data: ".$reqdata->getRequest());
  my $unixSocket = $ClientQueue->dequeue();   &StartRequest($Socket,  $reqdata);
  &Debug(6, "Starting new work request");  
  &Debug(7, "Request: ".$reqdata);  
   
  &StartRequest($Socket, $unixSocket, $reqdata);  
     } else {      } else {
   
     #  There's no work waiting, so push the server to idle list.      #  There's no work waiting, so push the server to idle list.
  &Debug(8, "No new work requests, server connection going idle");   &Debug(5, "No new work requests, server connection going idle");
  delete($ActiveTransactions{$Socket});  
  $IdleConnections->push($Socket);   $IdleConnections->push($Socket);
     }      }
 }  }
Line 260  sub ClientWritable { Line 427  sub ClientWritable {
     &Debug(6, "ClientWritable writing".$Data);      &Debug(6, "ClientWritable writing".$Data);
     &Debug(9, "Socket is: ".$Socket);      &Debug(9, "Socket is: ".$Socket);
   
     my $result = $Socket->send($Data, 0);      if($Socket->connected) {
    my $result = $Socket->send($Data, 0);
     # $result undefined: the write failed.  
     # otherwise $result is the number of bytes written.  
     # Remove that preceding string from the data.  
     # If the resulting data is empty, destroy the watcher  
     # and set up a read event handler to accept the next  
     # request.  
   
     &Debug(9,"Send result is ".$result." Defined: ".defined($result));  
     if(defined($result)) {  
  &Debug(9, "send result was defined");  
  if($result == length($Data)) { # Entire string sent.  
     &Debug(9, "ClientWritable data all written");  
     $Watcher->cancel();  
     #  
     #  Set up to read next request from socket:  
       
     my $descr     = sprintf("Connection to lonc client %d",  
     $ActiveClients{$Socket});  
     Event->io(cb    => \&ClientRequest,  
       poll  => 'r',  
       desc  => $descr,  
       data  => "",  
       fd    => $Socket);  
   
  } else { # Partial string sent.  
     $Watcher->data(substr($Data, $result));  
  }  
   
     } else { # Error of some sort...   # $result undefined: the write failed.
    # otherwise $result is the number of bytes written.
  # Some errnos are possible:   # Remove that preceding string from the data.
  my $errno = $!;   # If the resulting data is empty, destroy the watcher
  if($errno == POSIX::EWOULDBLOCK   ||   # and set up a read event handler to accept the next
    $errno == POSIX::EAGAIN        ||   # request.
    $errno == POSIX::EINTR) {  
     # No action taken?  
  } else { # Unanticipated errno.  
     &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);  
     $Watcher->cancel; # Stop the watcher.  
     $Socket->shutdown(2); # Kill connection  
     $Socket->close(); # Close the socket.  
  }  
   
    &Debug(9,"Send result is ".$result." Defined: ".defined($result));
    if($result ne undef) {
       &Debug(9, "send result was defined");
       if($result == length($Data)) { # Entire string sent.
    &Debug(9, "ClientWritable data all written");
    $Watcher->cancel();
    #
    #  Set up to read next request from socket:
   
    my $descr     = sprintf("Connection to lonc client %d",
    $ActiveClients{$Socket});
    Event->io(cb    => \&ClientRequest,
     poll  => 'r',
     desc  => $descr,
     data  => "",
     fd    => $Socket);
   
       } else { # Partial string sent.
    $Watcher->data(substr($Data, $result));
    if($result == 0) {    # client hung up on us!!
       Log("INFO", "lonc pipe client hung up on us!");
       $Watcher->cancel;
       $Socket->shutdown(2);
       $Socket->close();
    }
       }
       
    } else { # Error of some sort...
       
       # Some errnos are possible:
       my $errno = $!;
       if($errno == POSIX::EWOULDBLOCK   ||
          $errno == POSIX::EAGAIN        ||
          $errno == POSIX::EINTR) {
    # No action taken?
       } else { # Unanticipated errno.
    &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
    $Watcher->cancel; # Stop the watcher.
    $Socket->shutdown(2); # Kill connection
    $Socket->close(); # Close the socket.
       }
       
    }
       } else {
    $Watcher->cancel(); # A delayed request...just cancel.
     }      }
 }  }
   
Line 325  Parameters: Line 502  Parameters:
 Socket on which the lond transaction occured.  This is a  Socket on which the lond transaction occured.  This is a
 LondConnection. The data received is in the TransactionReply member.  LondConnection. The data received is in the TransactionReply member.
   
 =item Client  =item Transaction
   
 Unix domain socket open on the ultimate client.  The transaction that is being completed.
   
 =cut  =cut
   
 sub CompleteTransaction {  sub CompleteTransaction {
     &Debug(6,"Complete transaction");      &Debug(5,"Complete transaction");
     my $Socket = shift;      my $Socket = shift;
     my $Client = shift;      my $Transaction = shift;
   
       if (!$Transaction->isDeferred()) { # Normal transaction
    my $data   = $Socket->GetReply(); # Data to send.
    StartClientReply($Transaction, $data);
       } else { # Delete deferred transaction file.
    Log("SUCCESS", "A delayed transaction was completed");
    LogPerm("S:$Transaction->getClient() :".$Transaction->getRequest());
    unlink $Transaction->getFile();
       }
   }
   =pod
   =head1 StartClientReply
   
      Initiates a reply to a client where the reply data is a parameter.
   
     my $data   = $Socket->GetReply(); # Data to send.  =head2  parameters:
   
   =item Transaction
   
       The transaction for which we are responding to the client.
   
   =item data
   
       The data to send to apached client.
   
   =cut
   sub StartClientReply {
       my $Transaction   = shift;
       my $data     = shift;
   
   
       my $Client   = $Transaction->getClient();
   
     &Debug(8," Reply was: ".$data);      &Debug(8," Reply was: ".$data);
     my $Serial         = $ActiveClients{$Client};      my $Serial         = $ActiveClients{$Client};
Line 348  sub CompleteTransaction { Line 555  sub CompleteTransaction {
       cb       => \&ClientWritable,        cb       => \&ClientWritable,
       data     => $data);        data     => $data);
 }  }
   =pod
   =head2 FailTransaction
   
     Finishes a transaction with failure because the associated lond socket
     disconnected.  There are two possibilities:
     - The transaction is deferred: in which case we just quietly
       delete the transaction since there is no client connection.
     - The transaction is 'live' in which case we initiate the sending
       of "con_lost" to the client.
   
   Deleting the transaction means killing it from the 
   %ActiveTransactions hash.
   
   Parameters:
   
   =item client  
    
      The LondTransaction we are failing.
    
   =cut
   
   sub FailTransaction {
       my $transaction = shift;
       Log("WARNING", "Failing transaction ".$transaction->getRequest());
       Debug(1, "Failing transaction: ".$transaction->getRequest());
       if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
    my $client  = $transaction->getClient();
    Debug(1," Replying con_lost to ".$transaction->getRequest());
    StartClientReply($transaction, "con_lost\n");
       }
       if($ConnectionRetriesLeft <= 0) {
    Log("CRITICAL", "Host marked dead: ".GetServerHost());
       }
   
   }
   
   =pod
   =head1  EmptyQueue
   
     Fails all items in the work queue with con_lost.
     Note that each item in the work queue is a transaction.
   
   =cut
   sub EmptyQueue {
       $ConnectionRetriesLeft--; # Counts as connection failure too.
       while($WorkQueue->Count()) {
    my $request = $WorkQueue->dequeue(); # This is a transaction
    FailTransaction($request);
       }
   }
   
   =pod
   
   =head2 CloseAllLondConnections
   
   Close all connections open on lond prior to exit e.g.
   
   =cut
   sub CloseAllLondConnections {
       foreach my $Socket (keys %ActiveConnections) {
    KillSocket($Socket);
       }
   }
   =cut
   
   =pod
   
   =head2 KillSocket
    
   Destroys a socket.  This function can be called either when a socket
   has died of 'natural' causes or because a socket needs to be pruned due to
   idleness.  If the socket has died naturally, if there are no longer any 
   live connections a new connection is created (in case there are transactions
   in the queue).  If the socket has been pruned, it is never re-created.
   
   Parameters:
   
   =item Socket
    
     The socket to kill off.
   
   =item Restart
   
   nonzero if we are allowed to create a new connection.
   
   
   =cut
   sub KillSocket {
       my $Socket = shift;
   
       Log("WARNING", "Shutting down a socket");
       $Socket->Shutdown();
   
       #  If the socket came from the active connection set,
       #  delete its transaction... note that FailTransaction should
       #  already have been called!!!
       #  otherwise it came from the idle set.
       #  
       
       if(exists($ActiveTransactions{$Socket})) {
    delete ($ActiveTransactions{$Socket});
       }
       if(exists($ActiveConnections{$Socket})) {
    delete($ActiveConnections{$Socket});
       }
       $ConnectionCount--;
   
       #  If the connection count has gone to zero and there is work in the
       #  work queue, the work all gets failed with con_lost.
       #
       if($ConnectionCount == 0) {
    EmptyQueue();
       }
   }
   
 =pod  =pod
   
Line 409  transaction is in progress, the socket a Line 729  transaction is in progress, the socket a
 =cut  =cut
   
 sub LondReadable {  sub LondReadable {
   
     my $Event      = shift;      my $Event      = shift;
     my $Watcher    = $Event->w;      my $Watcher    = $Event->w;
     my $Socket     = $Watcher->data;      my $Socket     = $Watcher->data;
     my $client     = undef;      my $client     = undef;
   
       &Debug(6,"LondReadable called state = ".$Socket->GetState());
   
   
     my $State = $Socket->GetState(); # All action depends on the state.      my $State = $Socket->GetState(); # All action depends on the state.
   
     &Debug(6,"LondReadable called state = ".$State);  
     SocketDump(6, $Socket);      SocketDump(6, $Socket);
       my $status = $Socket->Readable();
   
     if($Socket->Readable() != 0) {      &Debug(2, "Socket->Readable returned: $status");
  # bad return from socket read.  
       if($status != 0) {
    # bad return from socket read. Currently this means that
    # The socket has become disconnected. We fail the transaction.
   
    Log("WARNING",
       "Lond connection lost.");
    if(exists($ActiveTransactions{$Socket})) {
       FailTransaction($ActiveTransactions{$Socket});
    }
    $Watcher->cancel();
    KillSocket($Socket);
    $ConnectionRetriesLeft--;       # Counts as connection failure
    return;
     }      }
     SocketDump(6,$Socket);      SocketDump(6,$Socket);
   
Line 436  sub LondReadable { Line 772  sub LondReadable {
  # in the connection takes care of setting that up.  Just   # in the connection takes care of setting that up.  Just
  # need to transition to writable:   # need to transition to writable:
   
  $Watcher->poll("w");  
  $Watcher->cb(\&LondWritable);   $Watcher->cb(\&LondWritable);
    $Watcher->poll("w");
   
     } elsif ($State eq "ChallengeReplied") {      } elsif ($State eq "ChallengeReplied") {
   
Line 446  sub LondReadable { Line 782  sub LondReadable {
  #  The ok was received.  Now we need to request the key   #  The ok was received.  Now we need to request the key
  #  That requires us to be writable:   #  That requires us to be writable:
   
  $Watcher->poll("w");  
  $Watcher->cb(\&LondWritable);   $Watcher->cb(\&LondWritable);
    $Watcher->poll("w");
   
     } elsif ($State eq "ReceivingKey") {      } elsif ($State eq "ReceivingKey") {
   
     } elsif ($State eq "Idle") {      } elsif ($State eq "Idle") {
  # If necessary, complete a transaction and then go into the   # If necessary, complete a transaction and then go into the
  # idle queue.   # idle queue.
    #  Note that a trasition to idle indicates a live lond
    # on the other end so reset the connection retries.
    #
    $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
    $Watcher->cancel();
  if(exists($ActiveTransactions{$Socket})) {   if(exists($ActiveTransactions{$Socket})) {
     Debug(8,"Completing transaction!!");      Debug(5,"Completing transaction!!");
     CompleteTransaction($Socket,       CompleteTransaction($Socket, 
  $ActiveTransactions{$Socket});   $ActiveTransactions{$Socket});
    } else {
       Log("SUCCESS", "Connection ".$ConnectionCount." to "
    .$RemoteHost." now ready for action");
  }   }
  $Watcher->cancel();  
  ServerToIdle($Socket); # Next work unit or idle.   ServerToIdle($Socket); # Next work unit or idle.
   
     } elsif ($State eq "SendingRequest") {      } elsif ($State eq "SendingRequest") {
  #  We need to be writable for this and probably don't belong   #  We need to be writable for this and probably don't belong
  #  here inthe first place.   #  here inthe first place.
Line 543  is the socket on which to return a reply Line 886  is the socket on which to return a reply
 sub LondWritable {  sub LondWritable {
     my $Event   = shift;      my $Event   = shift;
     my $Watcher = $Event->w;      my $Watcher = $Event->w;
     my @data    = $Watcher->data;      my $Socket  = $Watcher->data;
     Debug(6,"LondWritable State = ".$State." data has ".@data." elts.\n");      my $State   = $Socket->GetState();
   
     my $Socket  = $data[0]; # I know there's at least a socket.      Debug(6,"LondWritable State = ".$State."\n");
   
    
     #  Figure out what to do depending on the state of the socket:      #  Figure out what to do depending on the state of the socket:
           
   
     my $State   = $Socket->GetState();  
   
   
     SocketDump(6,$Socket);      SocketDump(6,$Socket);
   
     if      ($State eq "Connected")         {      if      ($State eq "Connected")         {
  #  "init" is being sent...  
   
  if ($Socket->Writable() != 0) {   if ($Socket->Writable() != 0) {
     #  The write resulted in an error.      #  The write resulted in an error.
       # We'll treat this as if the socket got disconnected:
       Log("WARNING", "Connection to ".$RemoteHost.
    " has been disconnected");
       FailTransaction($ActiveTransactions{$Socket});
       $Watcher->cancel();
       KillSocket($Socket);
       return;
  }   }
    #  "init" is being sent...
   
   
     } elsif ($State eq "Initialized")       {      } elsif ($State eq "Initialized")       {
   
  # Now that init was sent, we switch    # Now that init was sent, we switch 
  # to watching for readability:   # to watching for readability:
   
  $Watcher->poll("r");  
  $Watcher->cb(\&LondReadable);   $Watcher->cb(\&LondReadable);
    $Watcher->poll("r");
   
     } elsif ($State eq "ChallengeReceived") {      } elsif ($State eq "ChallengeReceived") {
  # We received the challenge, now we    # We received the challenge, now we 
Line 577  sub LondWritable { Line 928  sub LondWritable {
  # we're waiting for the state to change   # we're waiting for the state to change
   
  if($Socket->Writable() != 0) {   if($Socket->Writable() != 0) {
     # Write of the next chunk resulted in an error.  
       $Watcher->cancel();
       KillSocket($Socket);
       return;
  }   }
   
     } elsif ($State eq "ChallengeReplied")  {      } elsif ($State eq "ChallengeReplied")  {
  # The echo was sent back, so we switch   # The echo was sent back, so we switch
  # to watching readability.   # to watching readability.
   
  $Watcher->poll("r");  
  $Watcher->cb(\&LondReadable);   $Watcher->cb(\&LondReadable);
    $Watcher->poll("r");
   
     } elsif ($State eq "RequestingKey")     {      } elsif ($State eq "RequestingKey")     {
  # At this time we're requesting the key.   # At this time we're requesting the key.
Line 595  sub LondWritable { Line 949  sub LondWritable {
   
  if($Socket->Writable() != 0) {   if($Socket->Writable() != 0) {
     # Write resulted in an error.      # Write resulted in an error.
  }  
   
       $Watcher->cancel();
       KillSocket($Socket);
       return;
   
    }
     } elsif ($State eq "ReceivingKey")      {      } elsif ($State eq "ReceivingKey")      {
  # Now we need to wait for the key   # Now we need to wait for the key
  # to come back from the peer:   # to come back from the peer:
   
  $Watcher->poll("r");  
  $Watcher->cb(\&LondReadable);   $Watcher->cb(\&LondReadable);
    $Watcher->poll("r");
   
     } elsif ($State eq "SendingRequest")    {      } elsif ($State eq "SendingRequest")    {
  # At this time we are sending a request to the   # At this time we are sending a request to the
  # peer... write the next chunk:   # peer... write the next chunk:
   
  if($Socket->Writable() != 0) {   if($Socket->Writable() != 0) {
     # Write resulted in an error.  
   
       if(exists($ActiveTransactions{$Socket})) {
    Debug(3, "Lond connection lost, failing transactions");
    FailTransaction($ActiveTransactions{$Socket});
       }
       $Watcher->cancel();
       KillSocket($Socket);
       return;
       
  }   }
   
     } elsif ($State eq "ReceivingReply")    {      } elsif ($State eq "ReceivingReply")    {
  # The send has completed.  Wait for the   # The send has completed.  Wait for the
  # data to come in for a reply.   # data to come in for a reply.
  Debug(8,"Writable sent request/receiving reply");   Debug(8,"Writable sent request/receiving reply");
  $Watcher->poll("r");  
  $Watcher->cb(\&LondReadable);   $Watcher->cb(\&LondReadable);
    $Watcher->poll("r");
   
     } else {      } else {
  #  Control only passes here on an error:    #  Control only passes here on an error: 
Line 630  sub LondWritable { Line 995  sub LondWritable {
     }      }
           
 }  }
   =pod
       
   =cut
   sub QueueDelayed {
       Debug(3,"QueueDelayed called");
   
       my $path = "$perlvar{'lonSockDir'}/delayed";
   
       Debug(4, "Delayed path: ".$path);
       opendir(DIRHANDLE, $path);
       
       my @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
       closedir(DIRHANDLE);
       my $dfname;
       my $reqfile;
       foreach $dfname (sort  @alldelayed) {
    $reqfile = "$path/$dfname";
    Debug(4, "queueing ".$reqfile);
    my $Handle = IO::File->new($reqfile);
    my $cmd    = <$Handle>;
    chomp $cmd; # There may or may not be a newline...
    $cmd = $cmd."\n"; # now for sure there's exactly one newline.
    my $Transaction = LondTransaction->new($cmd);
    $Transaction->SetDeferred($reqfile);
    QueueTransaction($Transaction);
       }
       
   }
   
 =pod  =pod
   
Line 650  sub MakeLondConnection { Line 1043  sub MakeLondConnection {
     my $Connection = LondConnection->new(&GetServerHost(),      my $Connection = LondConnection->new(&GetServerHost(),
  &GetServerPort());   &GetServerPort());
   
     if($Connection == undef) { # Needs to be more robust later.      if($Connection eq undef) { # Needs to be more robust later.
  die "Failed to make a connection!!".$!."\n";   Log("CRITICAL","Failed to make a connection with lond.");
    $ConnectionRetriesLeft--;
    return 0; # Failure.
       }  else {
   
    # The connection needs to have writability 
    # monitored in order to send the init sequence
    # that starts the whole authentication/key
    # exchange underway.
    #
    my $Socket = $Connection->GetSocket();
    if($Socket eq undef) {
       die "did not get a socket from the connection";
    } else {
       &Debug(9,"MakeLondConnection got socket: ".$Socket);
    }
   
     }    $Connection->SetTimeoutCallback(\&SocketTimeout);
     # The connection needs to have writability   
     # monitored in order to send the init sequence  
     # that starts the whole authentication/key  
     # exchange underway.  
     #  
     my $Socket = $Connection->GetSocket();  
     if($Socket == undef) {  
  die "did not get a socket from the connection";  
     } else {  
  &Debug(9,"MakeLondConnection got socket: ".$Socket);  
     }  
   
       
     $event = Event->io(fd       => $Socket,  
        poll     => 'w',  
        cb       => \&LondWritable,  
        data     => ($Connection, undef),  
        desc => 'Connection to lond server');  
     $ActiveConnections{$Lond} = $event;  
   
     $ConnectionCount++;   my $event = Event->io(fd       => $Socket,
         poll     => 'w',
      cb       => \&LondWritable,
      data     => $Connection,
      desc => 'Connection to lond server');
    $ActiveConnections{$Connection} = $event;
   
    $ConnectionCount++;
    Debug(4, "Connection count = ".$ConnectionCount);
    if($ConnectionCount == 1) { # First Connection:
       QueueDelayed;
    }
    Log("SUCESS", "Created connection ".$ConnectionCount
       ." to host ".GetServerHost());
    return 1; # Return success.
       }
           
 }  }
   
Line 706  The text of the request to send. Line 1109  The text of the request to send.
   
 sub StartRequest {  sub StartRequest {
     my $Lond     = shift;      my $Lond     = shift;
     my $Client   = shift;      my $Request  = shift; # This is a LondTransaction.
     my $Request  = shift;  
           
     Debug(6, "StartRequest: ".$Request);      Debug(6, "StartRequest: ".$Request->getRequest());
   
     my $Socket = $Lond->GetSocket();      my $Socket = $Lond->GetSocket();
           
     $ActiveTransactions{$Lond} = $Client; # Socket to relay to client.      $Request->Activate($Lond);
       $ActiveTransactions{$Lond} = $Request;
   
     $Lond->InitiateTransaction($Request);      $Lond->InitiateTransaction($Request->getRequest());
     $event = Event->io(fd      => $Lond->GetSocket(),      my $event = Event->io(fd      => $Socket,
        poll    => "w",         poll    => "w",
        cb      => \&LondWritable,         cb      => \&LondWritable,
        data    => $Lond,         data    => $Lond,
Line 747  data to send to the lond. Line 1150  data to send to the lond.
 =cut  =cut
   
 sub QueueTransaction {  sub QueueTransaction {
     my $requestSocket = shift;  
     my $requestData   = shift;  
   
     Debug(6,"QueueTransaction: ".$requestData);      my $requestData   = shift; # This is a LondTransaction.
       my $cmd           = $requestData->getRequest();
   
       Debug(6,"QueueTransaction: ".$cmd);
   
     my $LondSocket    = $IdleConnections->pop();      my $LondSocket    = $IdleConnections->pop();
     if(!defined $LondSocket) { # Need to queue request.      if(!defined $LondSocket) { # Need to queue request.
  Debug(8,"Must queue...");   Debug(5,"Must queue...");
  $ClientQueue->enqueue($requestSocket);  
  $WorkQueue->enqueue($requestData);   $WorkQueue->enqueue($requestData);
  if($ConnectionCount < $MaxConnectionCount) {   if($ConnectionCount < $MaxConnectionCount) {
     Debug(4,"Starting additional lond connection");      if($ConnectionRetriesLeft > 0) {
     MakeLondConnection();   Debug(5,"Starting additional lond connection");
    if(MakeLondConnection() == 0) {
       EmptyQueue(); # Fail transactions, can't make connection.
    }
       } else {
    ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
    EmptyQueue(); # It's worse than that ... he's dead Jim.
       }
  }   }
     } else { # Can start the request:      } else { # Can start the request:
  Debug(8,"Can start...");   Debug(8,"Can start...");
  StartRequest($LondSocket, $requestSocket, $requestData);   StartRequest($LondSocket,  $requestData);
     }      }
 }  }
   
Line 772  sub QueueTransaction { Line 1182  sub QueueTransaction {
 =pod  =pod
   
 =head2 ClientRequest  =head2 ClientRequest
   
 Callback that is called when data can be read from the UNIX domain  Callback that is called when data can be read from the UNIX domain
 socket connecting us with an apache server process.  socket connecting us with an apache server process.
   
Line 791  sub ClientRequest { Line 1200  sub ClientRequest {
     my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);      my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
     Debug(8, "rcv:  data length = ".length($thisread)      Debug(8, "rcv:  data length = ".length($thisread)
   ." read =".$thisread);    ." read =".$thisread);
     unless (defined $rv && length($thisread)) {      unless (defined $rv  && length($thisread)) {
  # Likely eof on socket.   # Likely eof on socket.
  Debug(5,"Client Socket closed on lonc for ".$RemoteHost);   Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
  close($socket);   close($socket);
  $watcher->cancel();   $watcher->cancel();
  delete($ActiveClients{$socket});   delete($ActiveClients{$socket});
    return;
     }      }
     Debug(8,"Data: ".$data." this read: ".$thisread);      Debug(8,"Data: ".$data." this read: ".$thisread);
     $data = $data.$thisread; # Append new data.      $data = $data.$thisread; # Append new data.
     $watcher->data($data);      $watcher->data($data);
     if($data =~ /(.*\n)/) { # Request entirely read.      if($data =~ /(.*\n)/) { # Request entirely read.
    if($data eq "close_connection_exit\n") {
       Log("CRITICAL",
    "Request Close Connection ... exiting");
       CloseAllLondConnections();
       exit;
    }
  Debug(8, "Complete transaction received: ".$data);   Debug(8, "Complete transaction received: ".$data);
  QueueTransaction($socket, $data);   my $Transaction = LondTransaction->new($data);
    $Transaction->SetClient($socket);
    QueueTransaction($Transaction);
  $watcher->cancel(); # Done looking for input data.   $watcher->cancel(); # Done looking for input data.
     }      }
   
Line 865  Returns the host whose lond we talk with Line 1283  Returns the host whose lond we talk with
   
 =cut  =cut
   
 sub GetServerHost { # Stub - get this from config.  sub GetServerHost {
     return $RemoteHost; # Setup by the fork.      return $RemoteHost; # Setup by the fork.
 }  }
   
Line 877  Returns the lond port number. Line 1295  Returns the lond port number.
   
 =cut  =cut
   
 sub GetServerPort { # Stub - get this from config.  sub GetServerPort {
     return $perlvar{londPort};      return $perlvar{londPort};
 }  }
   
Line 898  sub SetupLoncListener { Line 1316  sub SetupLoncListener {
     my $socket;      my $socket;
     my $SocketName = GetLoncSocketPath();      my $SocketName = GetLoncSocketPath();
     unlink($SocketName);      unlink($SocketName);
     unless ($socket = IO::Socket::UNIX->new(Local  => $SocketName,      unless ($socket =IO::Socket::UNIX->new(Local  => $SocketName,
     Listen => 10,       Listen => 10, 
     Type   => SOCK_STREAM)) {      Type   => SOCK_STREAM)) {
  die "Failed to create a lonc listner socket";   die "Failed to create a lonc listner socket";
Line 909  sub SetupLoncListener { Line 1327  sub SetupLoncListener {
       fd     => $socket);        fd     => $socket);
 }  }
   
   =pod 
   
   =head2 ChildStatus
    
   Child USR1 signal handler to report the most recent status
   into the status file.
   
   We also use this to reset the retries count in order to allow the
   client to retry connections with a previously dead server.
   =cut
   sub ChildStatus {
       my $event = shift;
       my $watcher = $event->w;
   
       Debug(2, "Reporting child status because : ".$watcher->data);
       my $docdir = $perlvar{'lonDocRoot'};
       my $fh = IO::File->new(">>$docdir/lon-status/loncstatus.txt");
       print $fh $$."\t".$RemoteHost."\t".$Status."\t".
    $RecentLogEntry."\n";
       $ConnectionRetriesLeft = $ConnectionRetries;
   }
   
 =pod  =pod
   
   =head2 SignalledToDeath
   
   Called in response to a signal that causes a chid process to die.
   
   =cut
   
   
   sub SignalledToDeath {
       my $event  = shift;
       my $watcher= $event->w;
   
       Debug(2,"Signalled to death! via ".$watcher->data);
       my ($signal) = $watcher->data;
       chomp($signal);
       Log("CRITICAL", "Abnormal exit.  Child $$ for $RemoteHost "
    ."died through "."\"$signal\"");
       LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
       ."\"$signal\"");
       exit 0;
   
   }
   
   =head2 ToggleDebug
   
   This sub toggles trace debugging on and off.
   
   =cut
   
   sub ToggleDebug {
       my $Current    = $DebugLevel;
          $DebugLevel = $NextDebugLevel;
          $NextDebugLevel = $Current;
   
       Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
   
   }
   
 =head2 ChildProcess  =head2 ChildProcess
   
 This sub implements a child process for a single lonc daemon.  This sub implements a child process for a single lonc daemon.
Line 919  This sub implements a child process for Line 1396  This sub implements a child process for
   
 sub ChildProcess {  sub ChildProcess {
   
     print "Loncnew\n";  
   
     # For now turn off signals.      #
           #  Signals must be handled by the Event framework...
     $SIG{QUIT}  = IGNORE;  #
     $SIG{HUP}   = IGNORE;  
     $SIG{USR1}  = IGNORE;      Event->signal(signal   => "QUIT",
     $SIG{INT}   = IGNORE;    cb       => \&SignalledToDeath,
     $SIG{CHLD}  = IGNORE;    data     => "QUIT");
     $SIG{__DIE__}  = IGNORE;      Event->signal(signal   => "HUP",
     cb       => \&ChildStatus,
     data     => "HUP");
       Event->signal(signal   => "USR1",
     cb       => \&ChildStatus,
     data     => "USR1");
       Event->signal(signal   => "INT",
     cb       => \&ToggleDebug,
     data     => "INT");
   
     SetupTimer();      SetupTimer();
           
Line 940  sub ChildProcess { Line 1424  sub ChildProcess {
   
 # Setup the initial server connection:  # Setup the initial server connection:
           
     &MakeLondConnection();       # &MakeLondConnection(); // let first work requirest do it.
       
   
     Debug(9,"Entering event loop");      Debug(9,"Entering event loop");
     my $ret = Event::loop(); #  Start the main event loop.      my $ret = Event::loop(); #  Start the main event loop.
           
Line 952  sub ChildProcess { Line 1437  sub ChildProcess {
 #  Create a new child for host passed in:  #  Create a new child for host passed in:
   
 sub CreateChild {  sub CreateChild {
       my $sigset = POSIX::SigSet->new(SIGINT);
       sigprocmask(SIG_BLOCK, $sigset);
     my $host = shift;      my $host = shift;
     $RemoteHost = $host;      $RemoteHost = $host;
     Debug(3, "Forking off child for ".$RemoteHost);      Log("CRITICAL", "Forking server for ".$host);
     sleep(5);      my $pid          = fork;
     $pid          = fork;  
     if($pid) { # Parent      if($pid) { # Parent
  $ChildHash{$pid} = $RemoteHost;   $RemoteHost = "Parent";
    $ChildHash{$pid} = $host;
    $HostToPid{$host}= $pid;
    sigprocmask(SIG_UNBLOCK, $sigset);
   
     } else { # child.      } else { # child.
  ChildProcess;   ShowStatus("Connected to ".$RemoteHost);
    $SIG{INT} = 'DEFAULT';
    sigprocmask(SIG_UNBLOCK, $sigset);
    ChildProcess; # Does not return.
     }      }
   
 }  }
Line 974  sub CreateChild { Line 1467  sub CreateChild {
 #  Each exit gets logged and the child gets restarted.  #  Each exit gets logged and the child gets restarted.
 #  #
   
   #
   #   Fork and start in new session so hang-up isn't going to 
   #   happen without intent.
   #
   
   
   
   
   
   
   ShowStatus("Forming new session");
   my $childpid = fork;
   if ($childpid != 0) {
       sleep 4; # Give child a chacne to break to
       exit 0; # a new sesion.
   }
   #
   #   Write my pid into the pid file so I can be located
   #
   
   ShowStatus("Parent writing pid file:");
   my $execdir = $perlvar{'lonDaemons'};
   open (PIDSAVE, ">$execdir/logs/lonc.pid");
   print PIDSAVE "$$\n";
   close(PIDSAVE);
   
   
   
   if (POSIX::setsid() < 0) {
       print "Could not create new session\n";
       exit -1;
   }
   
   ShowStatus("Forking node servers");
   
   Log("CRITICAL", "--------------- Starting children ---------------");
   
   LondConnection::ReadConfig;               # Read standard config files.
 my $HostIterator = LondConnection::GetHostIterator;  my $HostIterator = LondConnection::GetHostIterator;
 while (! $HostIterator->end()) {  while (! $HostIterator->end()) {
   
     $hostentryref = $HostIterator->get();      my $hostentryref = $HostIterator->get();
     CreateChild($hostentryref->[0]);      CreateChild($hostentryref->[0]);
       $HostHash{$hostentryref->[0]} = $hostentryref->[4];
     $HostIterator->next();      $HostIterator->next();
 }  }
   $RemoteHost = "Parent Server";
   
 # Maintain the population:  # Maintain the population:
   
   ShowStatus("Parent keeping the flock");
   
   #
   #   Set up parent signals:
   #
   
   $SIG{INT}  = \&Terminate;
   $SIG{TERM} = \&Terminate; 
   $SIG{HUP}  = \&Restart;
   $SIG{USR1} = \&CheckKids; 
   $SIG{USR2} = \&UpdateKids; # LonManage update request.
   
 while(1) {  while(1) {
     $deadchild = wait();      my $deadchild = wait();
     if(exists $ChildHash{$deadchild}) { # need to restart.      if(exists $ChildHash{$deadchild}) { # need to restart.
  $deadhost = $ChildHash{$deadchild};   my $deadhost = $ChildHash{$deadchild};
    delete($HostToPid{$deadhost});
  delete($ChildHash{$deadchild});   delete($ChildHash{$deadchild});
  Debug(4,"Lost child pid= ".$deadchild.   Log("WARNING","Lost child pid= ".$deadchild.
       "Connected to host ".$deadhost);        "Connected to host ".$deadhost);
    Log("INFO", "Restarting child procesing ".$deadhost);
  CreateChild($deadhost);   CreateChild($deadhost);
     }      }
 }  }
   
   
   
   =pod
   
   =head1 CheckKids
   
     Since kids do not die as easily in this implementation
   as the previous one, there  is no need to restart the
   dead ones (all dead kids get restarted when they die!!)
   The only thing this function does is to pass USR1 to the
   kids so that they report their status.
   
   =cut
   
   sub CheckKids {
       Debug(2, "Checking status of children");
       my $docdir = $perlvar{'lonDocRoot'};
       my $fh = IO::File->new(">$docdir/lon-status/loncstatus.txt");
       my $now=time;
       my $local=localtime($now);
       print $fh "LONC status $local - parent $$ \n\n";
       foreach my $pid (keys %ChildHash) {
    Debug(2, "Sending USR1 -> $pid");
    kill 'USR1' => $pid; # Tell Child to report status.
    sleep 1; # Wait so file doesn't intermix.
       }
   }
   
   =pod
   
   =head1  UpdateKids
   
   parent's SIGUSR2 handler.  This handler:
   
   =item
   
   Rereads the hosts file.
   
   =item
    
   Kills off (via sigint) children for hosts that have disappeared.
   
   =item
   
   QUITs  children for hosts that already exist (this just forces a status display
   and resets the connection retry count for that host.
   
   =item
   
   Starts new children for hosts that have been added to the hosts.tab file since
   the start of the master program and maintains them.
   
   =cut
   
   sub UpdateKids {
   
       Log("INFO", "Updating connections via SIGUSR2");
   
       #  Just in case we need to kill our own lonc, we wait a few seconds to
       #  give it a chance to receive and relay lond's response to the 
       #  re-init command.
       #
   
       sleep(2); # Wait a couple of seconds.
   
       my %hosts;                   # Indexed by loncapa hostname, value=ip.
       
       # Need to re-read  the host table:
       
       
       LondConnection::ReadConfig();
       my $I = LondConnection::GetHostIterator;
       while (! $I->end()) {
    my $item = $I->get();
    $hosts{$item->[0]} = $item->[4];
    $I->next();
       }
   
       #  The logic below is written for clarity not for efficiency.
       #  Since I anticipate that this function is only rarely called, that's
       #  appropriate.  There are certainly ways to combine the loops below,
       #  and anyone wishing to obscure the logic is welcome to go for it.
       #  Note that we don't re-direct sigchild.  Instead we do what's needed
       #  to the data structures that keep track of children to ensure that
       #  when sigchild is honored, no new child is born.
       #
   
       #  For each existing child; if it's host doesn't exist, kill the child.
   
       foreach my $child (keys %ChildHash) {
    my $oldhost = $ChildHash{$child};
    if (!(exists $hosts{$oldhost})) {
       Log("CRITICAL", "Killing child for $oldhost  host no longer exists");
       delete $ChildHash{$child};
       delete $HostToPid{$oldhost};
       kill 'QUIT' => $child;
    }
       }
       # For each remaining existing child; if it's host's ip has changed,
       # Restart the child on the new IP.
   
       foreach my $child (keys %ChildHash) {
    my $oldhost = $ChildHash{$child};
    my $oldip   = $HostHash{$oldhost};
    if ($hosts{$oldhost} ne $oldip) {
   
       # kill the old child.
   
       Log("CRITICAL", "Killing child for $oldhost host ip has changed...");
       delete $ChildHash{$child};
       delete $HostToPid{$oldhost};
       kill 'QUIT' => $child;
   
       # Do the book-keeping needed to start a new child on the
       # new ip.
   
       $HostHash{$oldhost} = $hosts{$oldhost};
       CreateChild($oldhost);
    }
       }
       # Finally, for each new host, not in the host hash, create a
       # enter the host and create a new child.
       # Force a status display of any existing process.
   
       foreach my $host (keys %hosts) {
    if(!(exists $HostHash{$host})) {
       Log("INFO", "New host $host discovered in hosts.tab...");
       $HostHash{$host} = $hosts{$host};
       CreateChild($host);
    } else {
       kill 'HUP' => $HostToPid{$host};    # status display.
    }
       }
   }
   
   
   =pod
   
   =head1 Restart
   
   Signal handler for HUP... all children are killed and
   we self restart.  This is an el-cheapo way to re read
   the config file.
   
   =cut
   
   sub Restart {
       &KillThemAll; # First kill all the children.
       Log("CRITICAL", "Restarting");
       my $execdir = $perlvar{'lonDaemons'};
       unlink("$execdir/logs/lonc.pid");
       exec("$execdir/loncnew");
   }
   
   =pod
   
   =head1 KillThemAll
   
   Signal handler that kills all children by sending them a 
   SIGHUP.  Responds to sigint and sigterm.
   
   =cut
   
   sub KillThemAll {
       Debug(2, "Kill them all!!");
       local($SIG{CHLD}) = 'IGNORE';      # Our children >will< die.
       foreach my $pid (keys %ChildHash) {
    my $serving = $ChildHash{$pid};
    Debug(2, "Killing lonc for $serving pid = $pid");
    ShowStatus("Killing lonc for $serving pid = $pid");
    Log("CRITICAL", "Killing lonc for $serving pid = $pid");
    kill 'QUIT' => $pid;
    delete($ChildHash{$pid});
       }
       my $execdir = $perlvar{'lonDaemons'};
       unlink("$execdir/logs/lonc.pid");
   
   }
   
   =pod
   
   =head1 Terminate
    
   Terminate the system.
   
   =cut
   
   sub Terminate {
       KillThemAll;
       Log("CRITICAL","Master process exiting");
       exit 0;
   
   }
   =pod
   
 =head1 Theory  =head1 Theory
   
 The event class is used to build this as a single process with an  The event class is used to build this as a single process with an
Removed from v.1.3  
changed lines
  Added in v.1.34

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