--- loncom/lonmaxima 2006/03/03 23:41:38 1.5 +++ loncom/lonmaxima 2007/04/19 17:29:11 1.26 @@ -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 1.26 2007/04/19 17:29:11 raeburn Exp $ # # Copyright Michigan State University Board of Trustees # @@ -30,8 +30,7 @@ # http://www.lon-capa.org/ # - -use IPC::Open3; +use Expect; use IO::Select; use IO::Socket; use IO::File; @@ -44,7 +43,7 @@ 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 @@ -56,58 +55,18 @@ my $lastlog; # use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children $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}; + $children--; + delete($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 ----'); @@ -197,7 +156,7 @@ 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 +167,25 @@ $port = "$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: $!"; @@ -239,20 +197,17 @@ print PIDSAVE "$$\n"; close(PIDSAVE); &logthis("CRITICAL: ---------- Starting ----------"); &status('Starting'); - - - - + +# Install signal handlers. +$SIG{CHLD} = \&REAPER; +$SIG{INT} = $SIG{TERM} = \&HUNTSMAN; + # Fork off our children. for (1 .. $PREFORK) { &make_new_child($server); } -# Install signal handlers. -$SIG{CHLD} = \&REAPER; -$SIG{INT} = $SIG{TERM} = \&HUNTSMAN; - # And maintain the population. while (1) { &status('Parent process, sleeping'); @@ -269,14 +224,14 @@ sub make_new_child { # 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"; + or die("Can't unblock SIGINT for fork: $!\n"); $children{$pid} = 1; $children++; return; @@ -286,12 +241,44 @@ sub make_new_child { # unblock signals sigprocmask(SIG_UNBLOCK, $sigset) - or die "Can't unblock SIGINT for fork: $!\n"; + or die("Can't unblock SIGINT for fork: $!\n"); - &process_requests($server); + &logthis('New process started'); + + my $command=Expect->spawn('maxima'); + $command->log_stdout(0); + + &getmaximaoutput($command); + + for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) { + &status('Accepting connections'); + my $client = $server->accept() or last; + print $command "kill(all);\n"; + &getmaximaoutput($command); + &sync($command); + my $syntaxerr = 0; + while (my $cmd=<$client>) { + &status('Processing command'); + print $command &unescape($cmd); + my ($reply,$syntaxerr) = &getmaximaoutput($command,1); + print $client &escape($reply)."\n"; + if ($syntaxerr) { + last; + } elsif ($reply=~/^Error\:/) { + &logthis('Died through '.$reply); + $client->close(); + $command->hard_close(); + exit; + } + &sync($command); + &status('Waiting for commands'); + } + } # tidy up gracefully and finish + $command->soft_close(); + # this exit is VERY important, otherwise the child will become # a producer of more and more children, forking yourself into # process death. @@ -299,15 +286,68 @@ sub make_new_child { } } -sub process_requests { - my ($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"; +{ + my $counter; + sub sync { + my ($command)=@_; + $counter++; + my $expect=$counter.time; + print $command "$expect;\n"; + while (1) { + my $output=&getmaximaoutput($command,1); + if (($output=~/\Q$expect\E/) || ($output=~/^Error\:/)) { + return; + } } - } + } +} + +sub getmaximaoutput { + my ($command,$numcheck)=@_; + my $regexp = '\(\%i\d+\)'; + my $syntaxerr=0; + if ($numcheck) { + if ($command->match() =~ /\(\%i(\d+)\)/) { + my $nextmatch = $1+1; + $regexp = '(\(\%i'.$nextmatch.'\)|Incorrect syntax\:)'; + } + } + my $timeout = 20; + my (undef,$error,$matched,$output)=$command->expect($timeout, -re => $regexp); + if ($numcheck) { + if ($matched eq 'Incorrect syntax:') { + $syntaxerr = 1; + if (wantarray) { + return ($matched,$syntaxerr); + } else { + return $matched; + } + } + } + if ($error) { + if (wantarray) { + return ('Error: '.$error); + } else { + return 'Error: '.$error; + } + } + $output =~ s/\r+//g; # Remove Windows-style linebreaks + my $foundoutput=0; + my $realoutput=''; + foreach my $line (split(/\n/,$output)) { + if ($line=~/\;/) { $foundoutput=1; next; } + if (!$foundoutput) { next; } + if ($line=~/^Incorrect syntax:/) { $syntaxerr = 1; next; } + (my $label, $line) = ($line=~ /^(\(\%o\d+\))(.+)$/); + if ($label) { + $label=~s/\S/ /g; + $line=$label.$line; + } + $realoutput.=$line."\n"; + } + if (wantarray) { + return ($realoutput,$syntaxerr); + } else { + return $realoutput; + } }