--- loncom/lonmaxima 2006/03/03 22:35:09 1.2 +++ loncom/lonmaxima 2008/08/19 09:46:36 1.38 @@ -3,7 +3,7 @@ # The LearningOnline Network with CAPA # Connect to MAXIMA CAS # -# $Id: lonmaxima,v 1.2 2006/03/03 22:35:09 www Exp $ +# $Id: lonmaxima,v 1.38 2008/08/19 09:46:36 riegler Exp $ # # Copyright Michigan State University Board of Trustees # @@ -30,13 +30,7 @@ # 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 Expect; use IO::Select; use IO::Socket; use IO::File; @@ -45,59 +39,40 @@ use POSIX; use lib '/home/httpd/lib/perl/'; use LONCAPA::Configuration; -# Scary: cannot use strict!!! -##### use strict; - -sub maximareply { - my $cmd=shift; - my $reply=''; - my $error=''; - my $exitstatus=''; - - unless ($cmd=~/\;\n$/) { $cmd.=";\n"; } - my $pid = open3($cmd_in, $cmd_out, $cmd_err, 'maxima'); - $children{$pid} = 1; - - print $cmd_in $cmd; - close $cmd_in; +use strict; - &status("Command sent"); +# global variables +my $PREFORK = 5; # number of children to maintain +my $MAX_CLIENTS_PER_CHILD = 50; # number of clients each child should process +my $extra_children = 0; +my %children = (); # keys are current child process IDs +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 - 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); -} +use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children $status + $pidfile $port %perlvar $lastlog); # ------------------------------------------------------------ Service routines sub REAPER { # takes care of dead children # and MAXIMA processes $SIG{CHLD} = \&REAPER; my $pid = wait; - $children --; - delete $children{$pid}; + if (exists($children{$pid})) { + $children--; + delete($children{$pid}); + if ($extra_children) { + $extra_children--; + } + } } sub HUNTSMAN { # signal handler for SIGINT local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children - kill 'INT' => keys %children; + kill('INT' => keys(%children)); unlink($pidfile); unlink($port); &logthis('---- Shutdown ----'); @@ -109,7 +84,7 @@ sub HUNTSMAN { # si # --------------------------------------------------------------------- Logging sub logthis { - my $message=shift; + my ($message)=@_; my $execdir=$perlvar{'lonDaemons'}; my $fh=IO::File->new(">>$execdir/logs/lonmaxima.log"); my $now=time; @@ -121,7 +96,7 @@ sub logthis { # -------------------------------------------------------------- Status setting sub status { - my $what=shift; + my ($what)=@_; my $now=time; my $local=localtime($now); $status=$local.': '.$what; @@ -131,7 +106,7 @@ sub status { # -------------------------------------------------------- Escape Special Chars sub escape { - my $str=shift; + my ($str)=@_; $str =~ s/(\W)/"%".unpack('H2',$1)/eg; return $str; } @@ -139,7 +114,7 @@ sub escape { # ----------------------------------------------------- Un-Escape Special Chars sub unescape { - my $str=shift; + my ($str)=@_; $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg; return $str; } @@ -150,35 +125,40 @@ sub catchexception { $SIG{QUIT}='DEFAULT'; $SIG{__DIE__}='DEFAULT'; chomp($signal); - &logthis("CRITICAL: " - ."ABNORMAL EXIT. Child $$ died through " - ."\"$signal\""); + &logthis("CRITICAL: " + ."ABNORMAL EXIT. Child $$ died through " + ."\"$signal\""); die("Signal abend"); } - +sub child_announce_death { + $SIG{USR1} = \&child_announce_death; + if ($extra_children < $PREFORK*10) { + $extra_children++; + } +} + # ---------------------------------------------------------------- Main program # -------------------------------- Set signal handlers to record abnormal exits $SIG{'QUIT'}=\&catchexception; $SIG{__DIE__}=\&catchexception; +$SIG{USR1} = \&child_announce_death; # ---------------------------------- 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; +%perlvar=%{&LONCAPA::Configuration::read_conf('loncapa.conf')}; # ----------------------------- 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.' |\ + my $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}"; + my $subj="LON: User ID mismatch"; + system("echo 'User ID mismatch. lonmaxima must be run as user www.' |\ mailto $emailto -s '$subj' > /dev/null"); - exit 1; + exit 1; } # --------------------------------------------- Check if other instance running @@ -186,11 +166,12 @@ if ($wwwid!=$<) { $pidfile="$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"; } + 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"); @@ -199,97 +180,129 @@ $port = "$perlvar{'lonSockDir'}/maximaso unlink($port); -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: $!"; # ------------------------------------------------------- Write our PID on disk my $execdir=$perlvar{'lonDaemons'}; -open (PIDSAVE,">$execdir/logs/lonmaxima.pid"); +open(PIDSAVE,">$execdir/logs/lonmaxima.pid"); print PIDSAVE "$$\n"; close(PIDSAVE); &logthis("CRITICAL: ---------- Starting ----------"); &status('Starting'); - - - - -# Fork off our children. -for (1 .. $PREFORK) { - make_new_child( ); -} - + # Install signal handlers. $SIG{CHLD} = \&REAPER; $SIG{INT} = $SIG{TERM} = \&HUNTSMAN; +# Fork off our children. +for (1 .. $PREFORK) { + &make_new_child($server); +} + # 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++) { + for (my $i = $children; $i < $PREFORK+$extra_children; $i++) { &status('Parent process, starting child'); - make_new_child( ); # top up the child pool + &make_new_child($server); # top up the child pool } } sub make_new_child { - my $pid; - my $sigset; - + my ($server) = @_; + # block signal for fork - $sigset = POSIX::SigSet->new(SIGINT); + 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: $!" unless defined ($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; } else { # Child can *not* return from this subroutine. - $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before + + my $ppid = getppid(); # 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"; - } + or die("Can't unblock SIGINT for fork: $!\n"); + + &logthis('New process started'); + + my $command=Expect->spawn('maxima'); + # soft/hard_close can take awhile and we really + # don't care we just want it gone + $SIG{INT} = sub { + my $pid = $command->pid(); + kill('KILL'=>$pid); + exit; + }; + + $command->log_stdout(0); + #$command->log_file("$execdir/logs/lonmaxima.session.log"); + + for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) { + &status('Accepting connections'); + my $client = $server->accept() or last; + &sync($command); + print $command ("display2d:false;kill(all);reset();\n"); + &getmaximaoutput($command,2); + &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); + kill('USR1' => $ppid); + $client->close(); + $command->hard_close(); + exit; + } + &sync($command); + &status('Waiting for commands'); + } } - + + kill('USR1' => $ppid); + print $command ("quit();\n"); # tidy up gracefully and finish + sleep(15); + $command->soft_close(); # this exit is VERY important, otherwise the child will become # a producer of more and more children, forking yourself into @@ -297,3 +310,74 @@ sub make_new_child { exit; } } + +{ + 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 ($numcheck eq 2) { + # command was the killall so should get a full reset on + # command numbers + $regexp = '(\(\%i(1)\)|Incorrect syntax\:)'; + } elsif ($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 && $matched eq 'Incorrect syntax:') { + $syntaxerr = 1; + if (wantarray) { + return ($matched,$syntaxerr); + } else { + return $matched; + } + } + if ($error) { + return 'Error: '.$error; + } + $output =~ s/\r+//g; # Remove Windows-style linebreaks + my $foundoutput=0; + my $found_label=0; + my $realoutput=''; + foreach my $line (split(/\n/,$output)) { + if ($line=~/\;/) { $foundoutput=1; next; } + if (!$foundoutput) { next; } + if ($line=~/^Incorrect syntax:/) { $syntaxerr = 1; next; } + if ($line=~ /^(\(\%o\d+\))(.+)$/){ + my $label = $1; + $line = $2; + $label =~s/\S/ /g; + $line=$label.$line; + $found_label=1; + } + if ($found_label) { + $realoutput.=$line."\n"; + } + } + if (wantarray) { + return ($realoutput,$syntaxerr); + } else { + return $realoutput; + } +}