--- loncom/lonmaxima 2006/03/03 23:41:38 1.5 +++ 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 1.5 2006/03/03 23:41:38 albertel Exp $ +# $Id: lonmaxima,v 1.15 2006/03/08 15:58:03 www Exp $ # # Copyright Michigan State University Board of Trustees # @@ -43,71 +43,34 @@ use LONCAPA::Configuration; use strict; # global variables +my $STARTPORT = 5664; # port for first child's server my $PREFORK = 5; # number of children to maintain my $MAX_CLIENTS_PER_CHILD = 5; # number of clients each child should process my %children = (); # keys are current child process IDs +my %usedmaximaports = (); # keys are the used maximaports my $children = 0; # current number of children my $status; # string for current status my $pidfile; # file containg parent process pid 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 $status +use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children %usedmaximaports $status $pidfile $port %perlvar $lastlog); -sub maximareply { - my ($cmd) = @_; - my $reply=''; - my $error=''; - my $exitstatus=''; - - unless ($cmd=~/\;\n$/) { $cmd.=";\n"; } - - my ($cmd_in, $cmd_out, $cmd_err); - my $pid = open3($cmd_in, $cmd_out, $cmd_err, 'maxima'); - $children{$pid} = 1; - - print $cmd_in $cmd; - close($cmd_in); - - &status("Command sent"); - - my $selector = IO::Select->new(); - $selector->add($cmd_err, $cmd_out); - - while (my @ready = $selector->can_read) { - foreach my $fh (@ready) { - if (fileno($fh) == fileno($cmd_err)) { - $error.=<$cmd_err>; - } else { - my $line = scalar <$cmd_out>; - if ($line=~/^(\(\%o|\s)/) { - $line=~s/^\(.*\)/ /; - $reply.=$line; - } - } - $selector->remove($fh) if eof($fh); - } - } - close($cmd_out); - close($cmd_err); - &status("Command processed"); - return ($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}; + $children--; + &logthis("Child $pid for port or process $children{$pid} died"); + delete($usedmaximaports{$children{$pid}}); + delete($children{$pid}); } sub HUNTSMAN { # signal handler for SIGINT local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children - kill 'INT' => keys %children; + kill('INT' => keys(%children)); unlink($pidfile); unlink($port); &logthis('---- Shutdown ----'); @@ -166,8 +129,6 @@ sub catchexception { die("Signal abend"); } - - # ---------------------------------------------------------------- Main program # -------------------------------- Set signal handlers to record abnormal exits @@ -197,7 +158,7 @@ if (-e $pidfile) { my $lfh=IO::File->new("$pidfile"); my $pide=<$lfh>; chomp($pide); - if (kill 0 => $pide) { die "already running"; } + if (kill(0 => $pide)) { die "already running"; } } # ------------------------------------------------------- Listen to UNIX socket @@ -208,26 +169,25 @@ $port = "$perlvar{'lonSockDir'}/maximaso unlink($port); -my $server; -unless ( - $server = IO::Socket::UNIX->new(Local => $port, - Type => SOCK_STREAM, - Listen => 10 ) - ) { - my $st=120+int(rand(240)); - &logthis( - "WARNING: ". - "Can't make server socket ($st secs): .. exiting"); - sleep($st); - exit; - }; +my $server = IO::Socket::UNIX->new(Local => $port, + Type => SOCK_STREAM, + Listen => 10 ); +if (!$server) { + my $st=120+int(rand(240)); + + &logthis("WARNING: ". + "Can't make server socket ($st secs): .. exiting"); + + sleep($st); + exit; +} # ---------------------------------------------------- Fork once and dissociate my $fpid=fork; exit if $fpid; -die "Couldn't fork: $!" unless defined ($fpid); +die("Couldn't fork: $!") unless defined($fpid); POSIX::setsid() or die "Can't start new session: $!"; @@ -239,59 +199,107 @@ print PIDSAVE "$$\n"; close(PIDSAVE); &logthis("CRITICAL: ---------- Starting ----------"); &status('Starting'); - - + +# Install signal handlers. +$SIG{CHLD} = \&REAPER; +$SIG{INT} = $SIG{TERM} = \&HUNTSMAN; - +my $maximaport=$STARTPORT; # Fork off our children. for (1 .. $PREFORK) { - &make_new_child($server); + &make_new_child($server,$maximaport); + $maximaport++; } -# Install signal handlers. -$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 (my $i = $children; $i < $PREFORK; $i++) { &status('Parent process, starting child'); - &make_new_child($server); # top up the child pool + my $newport; + &logthis("Current pool: ".join(', ',keys %usedmaximaports)); + foreach my $testport ($STARTPORT .. $STARTPORT+$PREFORK-1) { + if (!$usedmaximaports{$testport}) { $newport=$testport; } + } + if ($newport) { + &make_new_child($server,$newport); # top up the child pool + } } } sub make_new_child { - my ($server) = @_; + my ($server,$maximaport) = @_; # block signal for fork my $sigset = POSIX::SigSet->new(SIGINT); sigprocmask(SIG_BLOCK, $sigset) - or die "Can't block SIGINT for fork: $!\n"; + or die("Can't block SIGINT for fork: $!\n"); - die "fork: $!" unless defined (my $pid = fork); + die("fork: $!") unless defined(my $pid = fork); if ($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; + 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 # unblock signals sigprocmask(SIG_UNBLOCK, $sigset) - or die "Can't unblock SIGINT for fork: $!\n"; - - &process_requests($server); + or die("Can't unblock SIGINT for fork: $!\n"); + + # open the MAXIMA port + my $maximaserver = IO::Socket::INET->new(LocalPort => $maximaport, + Type => SOCK_STREAM, + Proto => 'tcp', + Reuse => 1, + Listen => 10 ) + or die "making socket: $@\n"; + 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} = "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); + &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; $i++) { + &status('Accepting connections for '.$maximapid.' on '.$maximaport); + my $client = $server->accept() or last; + while (my $cmd=<$client>) { + &status('Processing command by '.$maximapid.' on '.$maximaport); + &maximawrite($maximaselect,&unescape($cmd).";\n"); + print $client &escape(&maximareply($maximaselect))."\n"; + } + } # tidy up gracefully and finish + if (ref($cmd_out)) { close($cmd_out); } + if (ref($cmd_err)) { close($cmd_err); } + if (ref($cmd_in)) { close($cmd_in); } + # this exit is VERY important, otherwise the child will become # a producer of more and more children, forking yourself into # process death. @@ -299,15 +307,26 @@ sub make_new_child { } } -sub process_requests { - my ($server) = @_; - # handle connections until we've reached $MAX_CLIENTS_PER_CHILD - for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) { - &status('Accepting connections'); - my $client = $server->accept() or last; - while (my $cmd=<$client>) { - &status('Processing command'); - print $client &escape((&maximareply(&unescape($cmd)))[0])."\n"; - } - } +sub maximareply { + my ($maximaselect)=@_; + my $output=''; + + foreach my $ready ($maximaselect->can_read(1)) { + my $data = ''; + my $rv = $ready->recv($data, POSIX::BUFSIZ, 0); + $output.=$data; + } + 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)); + } } + +