Diff for /loncom/lonmaxima between versions 1.1 and 1.2

version 1.1, 2006/03/03 16:07:34 version 1.2, 2006/03/03 22:35:09
Line 29 Line 29
 #   # 
 # http://www.lon-capa.org/  # http://www.lon-capa.org/
 #  #
   
   # global variables
   $PREFORK                = 5;        # number of children to maintain
   $MAX_CLIENTS_PER_CHILD  = 5;        # number of clients each child should process
   %children               = ();       # keys are current child process IDs
   $children               = 0;        # current number of children
     
 use IPC::Open3;  use IPC::Open3;
 use IO::Select;  use IO::Select;
   use IO::Socket;
   use IO::File;
   use Symbol;
   use POSIX;
   use lib '/home/httpd/lib/perl/';
   use LONCAPA::Configuration;
    
 # Scary: cannot use strict!!!  # Scary: cannot use strict!!!
 ##### use strict;  ##### use strict;
    
 sub maximareply {  sub maximareply {
     my $cmd=shift;      my $cmd=shift;
     my $reply='';      my $reply='';
Line 43  sub maximareply { Line 56  sub maximareply {
   
     unless ($cmd=~/\;\n$/) { $cmd.=";\n"; }      unless ($cmd=~/\;\n$/) { $cmd.=";\n"; }
     my $pid = open3($cmd_in, $cmd_out, $cmd_err, 'maxima');      my $pid = open3($cmd_in, $cmd_out, $cmd_err, 'maxima');
       $children{$pid} = 1;
           
     $SIG{CHLD} = sub {  
  $exitstatus="$? on $pid\n" if waitpid($pid, 0) > 0;  
     };  
   
     print $cmd_in $cmd;      print $cmd_in $cmd;
     close $cmd_in;      close $cmd_in;
   
     my $selector = IO::Select->new( );      &status("Command sent");
   
       my $selector = IO::Select->new();
     $selector->add($cmd_err, $cmd_out);      $selector->add($cmd_err, $cmd_out);
           
     while (my @ready = $selector->can_read) {      while (my @ready = $selector->can_read) {
Line 70  sub maximareply { Line 82  sub maximareply {
     }      }
     close $cmd_out;      close $cmd_out;
     close $cmd_err;      close $cmd_err;
       &status("Command processed");
     return ($reply,$error,$exitstatus);      return ($reply,$error,$exitstatus);
 }  }
    
   # ------------------------------------------------------------ Service routines 
   sub REAPER {                        # takes care of dead children 
                                       # and MAXIMA processes
       $SIG{CHLD} = \&REAPER;
       my $pid = wait;
       $children --;
       delete $children{$pid};
   }
    
   sub HUNTSMAN {                      # signal handler for SIGINT
       local($SIG{CHLD}) = 'IGNORE';   # we're going to kill our children
       kill 'INT' => keys %children;
       unlink($pidfile);
       unlink($port);
       &logthis('---- Shutdown ----');
       exit;                           # clean up with dignity
   }
   
   
    
   # --------------------------------------------------------------------- Logging
    
   sub logthis {
       my $message=shift;
       my $execdir=$perlvar{'lonDaemons'};
       my $fh=IO::File->new(">>$execdir/logs/lonmaxima.log");
       my $now=time;
       my $local=localtime($now);
       $lastlog=$local.': '.$message;
       print $fh "$local ($$): $message\n";
   }
    
   # -------------------------------------------------------------- Status setting
    
   sub status {
       my $what=shift;
       my $now=time;
       my $local=localtime($now);
       $status=$local.': '.$what;
       $0='lonmaxima: '.$what.' '.$local;
   }
    
   # -------------------------------------------------------- Escape Special Chars
    
   sub escape {
       my $str=shift;
       $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
       return $str;
   }
    
   # ----------------------------------------------------- Un-Escape Special Chars
    
   sub unescape {
       my $str=shift;
       $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
       return $str;
   }
    
   # ------------------------ grabs exception and records it to log before exiting
   sub catchexception {
       my ($signal)=@_;
       $SIG{QUIT}='DEFAULT';
       $SIG{__DIE__}='DEFAULT';
       chomp($signal);
       &logthis("<font color=red>CRITICAL: "
        ."ABNORMAL EXIT. Child $$ died through "
        ."\"$signal\"</font>");
       die("Signal abend");
   }
    
   
   
   # ---------------------------------------------------------------- Main program
   # -------------------------------- Set signal handlers to record abnormal exits
    
    
   $SIG{'QUIT'}=\&catchexception;
   $SIG{__DIE__}=\&catchexception;
    
   # ---------------------------------- Read loncapa_apache.conf and loncapa.conf
   &status("Read loncapa.conf and loncapa_apache.conf");
   my $perlvarref=LONCAPA::Configuration::read_conf('loncapa.conf');
   %perlvar=%{$perlvarref};
   undef $perlvarref;
    
   # ----------------------------- Make sure this process is running from user=www
   my $wwwid=getpwnam('www');
   if ($wwwid!=$<) {
      my $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
      my $subj="LON: $currenthostid User ID mismatch";
      system("echo 'User ID mismatch.  lonmaxima must be run as user www.' |\
    mailto $emailto -s '$subj' > /dev/null");
      exit 1;
   }
    
   # --------------------------------------------- Check if other instance running
    
   $pidfile="$perlvar{'lonDaemons'}/logs/lonmaxima.pid";
    
   if (-e $pidfile) {
      my $lfh=IO::File->new("$pidfile");
      my $pide=<$lfh>;
      chomp($pide);
      if (kill 0 => $pide) { die "already running"; }
   }
   # ------------------------------------------------------- Listen to UNIX socket
   &status("Opening socket");
    
   $port = "$perlvar{'lonSockDir'}/maximasock";
    
   unlink($port);
    
   
   unless (
     $server = IO::Socket::UNIX->new(Local  => $port,
                                     Type   => SOCK_STREAM,
                                     Listen => 10 )
      ) {
          my $st=120+int(rand(240));
          &logthis(
            "<font color=blue>WARNING: ".
            "Can't make server socket ($st secs):  .. exiting</font>");
          sleep($st);
          exit;
        };
       
    
   # ---------------------------------------------------- Fork once and dissociate
    
   my $fpid=fork;
   exit if $fpid;
   die "Couldn't fork: $!" unless defined ($fpid);
    
   POSIX::setsid() or die "Can't start new session: $!";
    
   # ------------------------------------------------------- Write our PID on disk
    
   my $execdir=$perlvar{'lonDaemons'};
   open (PIDSAVE,">$execdir/logs/lonmaxima.pid");
   print PIDSAVE "$$\n";
   close(PIDSAVE);
   &logthis("<font color='red'>CRITICAL: ---------- Starting ----------</font>");
   &status('Starting');
    
    
   
   
        
   # Fork off our children.
   for (1 .. $PREFORK) {
       make_new_child( );
   }
    
   # Install signal handlers.
   $SIG{CHLD} = \&REAPER;
   $SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
    
   # And maintain the population.
   while (1) {
       &status('Parent process, sleeping');
       sleep;                          # wait for a signal (i.e., child's death)
       for ($i = $children; $i < $PREFORK; $i++) {
           &status('Parent process, starting child');
           make_new_child( );           # top up the child pool
       }
   }
                                                                                   
   sub make_new_child {
       my $pid;
       my $sigset;
        
       # block signal for fork
       $sigset = POSIX::SigSet->new(SIGINT);
       sigprocmask(SIG_BLOCK, $sigset)
           or die "Can't block SIGINT for fork: $!\n";
        
       die "fork: $!" unless defined ($pid = fork);
        
       if ($pid) {
           # Parent records the child's birth and returns.
           sigprocmask(SIG_UNBLOCK, $sigset)
               or die "Can't unblock SIGINT for fork: $!\n";
           $children{$pid} = 1;
           $children++;
           return;
       } else {
           # Child can *not* return from this subroutine.
           $SIG{INT} = 'DEFAULT';      # make SIGINT kill us as it did before
        
           # unblock signals
           sigprocmask(SIG_UNBLOCK, $sigset)
               or die "Can't unblock SIGINT for fork: $!\n";
            
           # handle connections until we've reached $MAX_CLIENTS_PER_CHILD
           for ($i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
       &status('Accepting connections');     
               $client = $server->accept( )     or last;
               while ($cmd=<$client>) {
    &status('Processing command');
    print $client &escape((&maximareply(&unescape($cmd)))[0])."\n";
       }
           }
        
           # tidy up gracefully and finish
   
 print join("\n----\n",&maximareply('1234'));          # this exit is VERY important, otherwise the child will become
 print join("\n----\n",&maximareply('x0: 5;x1: 7;integrate (x^2, x, x0, x1);'));          # a producer of more and more children, forking yourself into
           # process death.
           exit;
       }
   }

Removed from v.1.1  
changed lines
  Added in v.1.2


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