--- loncom/lonmaxima	2006/03/08 12:57:30	1.13
+++ loncom/lonmaxima	2006/03/08 15:58:03	1.15
@@ -3,7 +3,7 @@
 # The LearningOnline Network with CAPA
 # Connect to MAXIMA CAS
 #
-# $Id: lonmaxima,v 1.13 2006/03/08 12:57:30 www Exp $
+# $Id: lonmaxima,v 1.15 2006/03/08 15:58:03 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -37,8 +37,6 @@ use IO::Socket;
 use IO::File;
 use Symbol;
 use POSIX;
-use Fcntl;
-use Socket;
 use lib '/home/httpd/lib/perl/';
 use LONCAPA::Configuration;
  
@@ -65,6 +63,7 @@ sub REAPER {                        # ta
     $SIG{CHLD} = \&REAPER;
     my $pid = wait;
     $children--;
+    &logthis("Child $pid for port or process $children{$pid} died");
     delete($usedmaximaports{$children{$pid}});
     delete($children{$pid});
 }
@@ -130,18 +129,6 @@ sub catchexception {
     die("Signal abend");
 }
 
-# -------------------------------------------------- make a socket non-blocking
-sub nonblock {
-    my $socket = shift;
-    my $flags;
-    if (ref($socket)) { 
-       $flags = fcntl($socket, F_GETFL, 0)
-            or die "Can't get flags for socket: $!\n";
-       fcntl($socket, F_SETFL, $flags | O_NONBLOCK)
-            or die "Can't make socket nonblocking: $!\n";
-    }
-}
-
 # ---------------------------------------------------------------- Main program
 # -------------------------------- Set signal handlers to record abnormal exits
  
@@ -232,10 +219,13 @@ while (1) {
     for (my $i = $children; $i < $PREFORK; $i++) {
         &status('Parent process, starting child');
         my $newport;
-        foreach $newport ($STARTPORT .. $STARTPORT+$PREFORK-1) {
-            if (!defined($usedmaximaports{$newport})) { last; }
+        &logthis("Current pool: ".join(', ',keys %usedmaximaports));
+        foreach my $testport ($STARTPORT .. $STARTPORT+$PREFORK-1) {
+            if (!$usedmaximaports{$testport}) { $newport=$testport; }
+        }
+        if ($newport) {
+           &make_new_child($server,$newport);           # top up the child pool
         }
-        &make_new_child($server,$newport);           # top up the child pool
     }
 }
                                                                                 
@@ -255,8 +245,10 @@ sub make_new_child {
             or die("Can't unblock SIGINT for fork: $!\n");
         $children{$pid} = $maximaport;
         $children++;
+        $usedmaximaports{$maximaport}=1;
         return;
     } else {
+        &logthis("Starting child on port $maximaport");
         # Child can *not* return from this subroutine.
         $SIG{INT} = 'DEFAULT';      # make SIGINT kill us as it did before
      
@@ -271,23 +263,25 @@ sub make_new_child {
                                               Reuse     => 1,
                                               Listen    => 10 )
                         or die "making socket: $@\n";
-        &nonblock($maximaserver);
         my $maximaselect=IO::Select->new($maximaserver);
+        sleep(1);
 
         # open MAXIMA to talk to that port
         my ($cmd_in, $cmd_out, $cmd_err);
         my $maximapid = open3($cmd_in, $cmd_out, $cmd_err, "maxima -s $maximaport");
-        $children{$maximapid} = 1;
+        $children{$maximapid} = "Maxima $maximapid port $maximaport";
         my $prompt=<$cmd_out>;
         &logthis("Maxima $maximapid: $prompt");
 
         # hopefully, MAXIMA calls us back
         &status("Waiting $maximapid on $maximaport");
         my $maximaclient=$maximaserver->accept();
+        $maximaclient->blocking(0);
         $maximaselect->add($maximaclient);
-        &nonblock($maximaclient);
         &status("$maximapid on $maximaport connected.");
         &logthis("Maxima $maximapid on port $maximaport connected.");
+        sleep(2);
+
         &logthis('Initial reply: '.&maximareply($maximaselect));
         # handle connections until we've reached $MAX_CLIENTS_PER_CHILD
         for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
@@ -295,7 +289,7 @@ sub make_new_child {
             my $client = $server->accept()     or last;
             while (my $cmd=<$client>) {
                 &status('Processing command by '.$maximapid.' on '.$maximaport);
-                print $maximaclient &unescape($cmd).";\n";
+                &maximawrite($maximaselect,&unescape($cmd).";\n");
                 print $client &escape(&maximareply($maximaselect))."\n";
             }
         }
@@ -316,6 +310,7 @@ sub make_new_child {
 sub maximareply {
    my ($maximaselect)=@_;
    my $output='';
+   
    foreach my $ready ($maximaselect->can_read(1)) {
        my $data = '';
        my $rv   = $ready->recv($data, POSIX::BUFSIZ, 0);
@@ -324,3 +319,14 @@ sub maximareply {
    return $output;
 }
 
+sub maximawrite {
+   my ($maximaselect,$cmd)=@_;
+   my $ready=($maximaselect->can_write(1));
+   if (ref($ready)) {
+      print $ready $cmd;
+   } else {
+      &logthis("Cannot write: ".&maximareply($maximaselect));
+   }
+}
+
+