--- loncom/lonmaxima	2006/03/08 22:30:11	1.16
+++ loncom/lonmaxima	2006/05/10 02:15:51	1.20
@@ -3,7 +3,7 @@
 # The LearningOnline Network with CAPA
 # Connect to MAXIMA CAS
 #
-# $Id: lonmaxima,v 1.16 2006/03/08 22:30:11 www Exp $
+# $Id: lonmaxima,v 1.20 2006/05/10 02:15:51 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -44,7 +44,7 @@ use strict;
 
 # global variables
 my $PREFORK                = 5;        # number of children to maintain
-my $MAX_CLIENTS_PER_CHILD  = 5;        # number of clients each child should process
+my $MAX_CLIENTS_PER_CHILD  = 50;       # number of clients each child should process
 my %children               = ();       # keys are current child process IDs
 my $children               = 0;        # current number of children
 my $status;                            # string for current status
@@ -52,6 +52,7 @@ my $pidfile;                           #
 my $port;                              # path to UNIX socket file
 my %perlvar;                           # configuration file info
 my $lastlog;                           # last string that was logged
+
 use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children $status
 	    $pidfile $port %perlvar $lastlog);
  
@@ -243,6 +244,8 @@ sub make_new_child {
         sigprocmask(SIG_UNBLOCK, $sigset)
             or die("Can't unblock SIGINT for fork: $!\n");
 
+        &logthis('New process started');
+
         my $command=Expect->spawn('maxima');
         $command->log_stdout(0);
 
@@ -251,10 +254,22 @@ sub make_new_child {
         for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
            &status('Accepting connections');
            my $client = $server->accept()     or last;
+           print $command "kill(all);reset();\n";
+	   &getmaximaoutput($command);
+           &sync($command);
            while (my $cmd=<$client>) {
               &status('Processing command');
-              print $command &unescape($cmd).";\n";
-              print $client &escape(&getmaximaoutput($command))."\n";
+              print $command &unescape($cmd);
+              my $reply=&getmaximaoutput($command);
+              print $client &escape($reply)."\n";
+              if ($reply=~/^Error\:/) {
+                 &logthis('Died through '.$reply);
+                 $client->close();
+                 $command->hard_close();     
+                 exit;
+              }	      
+	      &sync($command);
+              &status('Waiting for commands');
            }
         }
 
@@ -269,9 +284,28 @@ sub make_new_child {
     }
 }
 
+{
+    my $counter;
+    sub sync {
+	my ($command)=@_;
+	$counter++;
+	my $expect=$counter.time;
+	print $command "$expect;\n";
+	while (1) {
+	    my $output=&getmaximaoutput($command);
+	    if (($output=~/\Q$expect\E/) || ($output=~/^Error\:/)) {
+		return;
+	    }
+	}
+    }
+}
+
 sub getmaximaoutput {
     my ($command)=@_;
-    my (undef,undef,undef,$output)=$command->expect(20, -re => '\(\%i\d+\)');
+    my (undef,$error,undef,$output)=$command->expect(20, -re => '\(\%i\d+\)');
+    if ($error) {
+       return 'Error: '.$error;
+    }
     my $foundoutput=0;
     my $realoutput='';
     foreach my $line (split(/\n/,$output)) {