Annotation of loncom/lonmaxima, revision 1.43

1.1       www         1: #!/usr/bin/perl
                      2: #
                      3: # The LearningOnline Network with CAPA
                      4: # Connect to MAXIMA CAS
                      5: #
1.43    ! raeburn     6: # $Id: lonmaxima,v 1.42 2013/07/04 11:44:44 droeschl Exp $
1.1       www         7: #
                      8: # Copyright Michigan State University Board of Trustees
                      9: #
                     10: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
                     11: #
                     12: # LON-CAPA is free software; you can redistribute it and/or modify
                     13: # it under the terms of the GNU General Public License as published by
                     14: # the Free Software Foundation; either version 2 of the License, or
                     15: # (at your option) any later version.
                     16: #
                     17: # LON-CAPA is distributed in the hope that it will be useful,
                     18: # but WITHOUT ANY WARRANTY; without even the implied warranty of
                     19: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     20: # GNU General Public License for more details.
                     21: #
                     22: # You should have received a copy of the GNU General Public License
                     23: # along with LON-CAPA; if not, write to the Free Software
                     24: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
                     25: #
                     26: # /home/httpd/html/adm/gpl.txt
                     27: #
                     28: 
                     29: # 
                     30: # http://www.lon-capa.org/
                     31: #
1.2       www        32: 
1.16      www        33: use Expect; 
1.1       www        34: use IO::Select;
1.2       www        35: use IO::Socket;
                     36: use IO::File;
                     37: use Symbol;
                     38: use POSIX;
                     39: use lib '/home/httpd/lib/perl/';
                     40: use LONCAPA::Configuration;
                     41:  
1.3       albertel   42: use strict;
                     43: 
                     44: # global variables
                     45: my $PREFORK                = 5;        # number of children to maintain
1.17      www        46: my $MAX_CLIENTS_PER_CHILD  = 50;       # number of clients each child should process
1.35      albertel   47: my $extra_children         = 0;
1.3       albertel   48: my %children               = ();       # keys are current child process IDs
                     49: my $children               = 0;        # current number of children
                     50: my $status;                            # string for current status
1.5       albertel   51: my $pidfile;                           # file containg parent process pid
                     52: my $port;                              # path to UNIX socket file
                     53: my %perlvar;                           # configuration file info
                     54: my $lastlog;                           # last string that was logged
1.18      www        55: 
1.16      www        56: use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children $status
1.12      www        57: 	    $pidfile $port %perlvar $lastlog);
1.2       www        58:  
                     59: # ------------------------------------------------------------ Service routines 
                     60: sub REAPER {                        # takes care of dead children 
                     61:                                     # and MAXIMA processes
                     62:     $SIG{CHLD} = \&REAPER;
                     63:     my $pid = wait;
1.35      albertel   64:     if (exists($children{$pid})) {
                     65: 	$children--;
                     66: 	delete($children{$pid});
                     67: 	if ($extra_children) {
                     68: 	    $extra_children--;
                     69: 	}
                     70:     }    
1.2       www        71: }
                     72:  
                     73: sub HUNTSMAN {                      # signal handler for SIGINT
                     74:     local($SIG{CHLD}) = 'IGNORE';   # we're going to kill our children
1.6       albertel   75:     kill('INT' => keys(%children));
1.2       www        76:     unlink($pidfile);
                     77:     unlink($port);
                     78:     &logthis('---- Shutdown ----');
                     79:     exit;                           # clean up with dignity
                     80: }
                     81: 
                     82: 
                     83:  
                     84: # --------------------------------------------------------------------- Logging
                     85:  
                     86: sub logthis {
1.4       albertel   87:     my ($message)=@_;
1.2       www        88:     my $execdir=$perlvar{'lonDaemons'};
                     89:     my $fh=IO::File->new(">>$execdir/logs/lonmaxima.log");
                     90:     my $now=time;
                     91:     my $local=localtime($now);
                     92:     $lastlog=$local.': '.$message;
                     93:     print $fh "$local ($$): $message\n";
                     94: }
                     95:  
                     96: # -------------------------------------------------------------- Status setting
                     97:  
                     98: sub status {
1.4       albertel   99:     my ($what)=@_;
1.2       www       100:     my $now=time;
                    101:     my $local=localtime($now);
                    102:     $status=$local.': '.$what;
                    103:     $0='lonmaxima: '.$what.' '.$local;
                    104: }
                    105:  
                    106: # -------------------------------------------------------- Escape Special Chars
                    107:  
                    108: sub escape {
1.4       albertel  109:     my ($str)=@_;
1.2       www       110:     $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
                    111:     return $str;
                    112: }
                    113:  
                    114: # ----------------------------------------------------- Un-Escape Special Chars
                    115:  
                    116: sub unescape {
1.4       albertel  117:     my ($str)=@_;
1.2       www       118:     $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
                    119:     return $str;
                    120: }
                    121:  
                    122: # ------------------------ grabs exception and records it to log before exiting
                    123: sub catchexception {
                    124:     my ($signal)=@_;
                    125:     $SIG{QUIT}='DEFAULT';
                    126:     $SIG{__DIE__}='DEFAULT';
                    127:     chomp($signal);
1.5       albertel  128:     &logthis("<font color=\"red\">CRITICAL: "
                    129: 	     ."ABNORMAL EXIT. Child $$ died through "
                    130: 	     ."\"$signal\"</font>");
1.2       www       131:     die("Signal abend");
                    132: }
1.5       albertel  133: 
1.16      www       134: 
1.35      albertel  135: sub child_announce_death {
                    136:     $SIG{USR1} = \&child_announce_death;
1.36      albertel  137:     if ($extra_children < $PREFORK*10) {
                    138: 	$extra_children++;
                    139:     }
1.35      albertel  140: }
1.16      www       141: 
1.2       www       142: # ---------------------------------------------------------------- Main program
                    143: # -------------------------------- Set signal handlers to record abnormal exits
                    144:  
                    145:  
                    146: $SIG{'QUIT'}=\&catchexception;
                    147: $SIG{__DIE__}=\&catchexception;
1.35      albertel  148: $SIG{USR1} = \&child_announce_death;
1.2       www       149:  
                    150: # ---------------------------------- Read loncapa_apache.conf and loncapa.conf
                    151: &status("Read loncapa.conf and loncapa_apache.conf");
1.3       albertel  152: %perlvar=%{&LONCAPA::Configuration::read_conf('loncapa.conf')};
1.2       www       153:  
                    154: # ----------------------------- Make sure this process is running from user=www
                    155: my $wwwid=getpwnam('www');
                    156: if ($wwwid!=$<) {
1.5       albertel  157:     my $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
                    158:     my $subj="LON: User ID mismatch";
1.43    ! raeburn   159:     system("echo 'User ID mismatch.  lonmaxima must be run as user www.' |".
        !           160:            " mailto -s '$subj' $emailto > /dev/null");
1.5       albertel  161:     exit 1;
1.2       www       162: }
                    163:  
                    164: # --------------------------------------------- Check if other instance running
                    165:  
                    166: $pidfile="$perlvar{'lonDaemons'}/logs/lonmaxima.pid";
                    167:  
                    168: if (-e $pidfile) {
1.5       albertel  169:     my $lfh=IO::File->new("$pidfile");
                    170:     my $pide=<$lfh>;
                    171:     chomp($pide);
1.6       albertel  172:     if (kill(0 => $pide)) { die "already running"; }
1.2       www       173: }
1.5       albertel  174: 
1.2       www       175: # ------------------------------------------------------- Listen to UNIX socket
                    176: &status("Opening socket");
                    177:  
                    178: $port = "$perlvar{'lonSockDir'}/maximasock";
                    179:  
                    180: unlink($port);
                    181:  
                    182: 
1.6       albertel  183: my $server = IO::Socket::UNIX->new(Local  => $port,
                    184: 				   Type   => SOCK_STREAM,
                    185: 				   Listen => 10 );
                    186: if (!$server) {
                    187:     my $st=120+int(rand(240));
                    188: 
                    189:     &logthis("<font color=blue>WARNING: ".
                    190: 	     "Can't make server socket ($st secs):  .. exiting</font>");
                    191: 
                    192:     sleep($st);
                    193:     exit;
                    194: }
1.2       www       195:     
                    196:  
                    197: # ---------------------------------------------------- Fork once and dissociate
                    198:  
                    199: my $fpid=fork;
                    200: exit if $fpid;
1.6       albertel  201: die("Couldn't fork: $!") unless defined($fpid);
1.2       www       202:  
                    203: POSIX::setsid() or die "Can't start new session: $!";
                    204:  
                    205: # ------------------------------------------------------- Write our PID on disk
                    206:  
                    207: my $execdir=$perlvar{'lonDaemons'};
1.5       albertel  208: open(PIDSAVE,">$execdir/logs/lonmaxima.pid");
1.2       www       209: print PIDSAVE "$$\n";
                    210: close(PIDSAVE);
                    211: &logthis("<font color='red'>CRITICAL: ---------- Starting ----------</font>");
                    212: &status('Starting');
1.6       albertel  213:      
1.2       www       214: 
1.10      albertel  215: # Install signal handlers.
                    216: $SIG{CHLD} = \&REAPER;
                    217: $SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
1.16      www       218:  
1.2       www       219: # Fork off our children.
                    220: for (1 .. $PREFORK) {
1.16      www       221:     &make_new_child($server);
1.2       www       222: }
                    223:  
                    224: # And maintain the population.
                    225: while (1) {
                    226:     &status('Parent process, sleeping');
                    227:     sleep;                          # wait for a signal (i.e., child's death)
1.35      albertel  228:     for (my $i = $children; $i < $PREFORK+$extra_children; $i++) {
1.2       www       229:         &status('Parent process, starting child');
1.16      www       230:         &make_new_child($server);           # top up the child pool
1.2       www       231:     }
                    232: }
                    233:                                                                                 
                    234: sub make_new_child {
1.16      www       235:     my ($server) = @_;
1.4       albertel  236: 
1.2       www       237:     # block signal for fork
1.4       albertel  238:     my $sigset = POSIX::SigSet->new(SIGINT);
1.2       www       239:     sigprocmask(SIG_BLOCK, $sigset)
1.6       albertel  240:         or die("Can't block SIGINT for fork: $!\n");
1.2       www       241:      
1.6       albertel  242:     die("fork: $!") unless defined(my $pid = fork);
1.2       www       243:      
                    244:     if ($pid) {
                    245:         # Parent records the child's birth and returns.
                    246:         sigprocmask(SIG_UNBLOCK, $sigset)
1.6       albertel  247:             or die("Can't unblock SIGINT for fork: $!\n");
1.16      www       248:         $children{$pid} = 1;
1.2       www       249:         $children++;
                    250:         return;
                    251:     } else {
                    252:         # Child can *not* return from this subroutine.
1.30      albertel  253:         
1.35      albertel  254: 	my $ppid = getppid();
1.2       www       255:      
                    256:         # unblock signals
                    257:         sigprocmask(SIG_UNBLOCK, $sigset)
1.6       albertel  258:             or die("Can't unblock SIGINT for fork: $!\n");
1.15      www       259: 
1.17      www       260:         &logthis('New process started');
                    261: 
1.42      droeschl  262:         my $command = new Expect();
                    263:         $command->log_stdout(0);
                    264:         #$command->log_file("$execdir/logs/lonmaxima.session.log");
                    265:         $command->spawn('maxima');
                    266:         &getmaximaoutput($command, 2); # wait for maxima to finish initialization
1.30      albertel  267: 	# soft/hard_close can take awhile and we really
                    268:         # don't care we just want it gone
                    269: 	$SIG{INT} = sub {
                    270: 	    my $pid = $command->pid();
                    271: 	    kill('KILL'=>$pid);
                    272: 	    exit; 
                    273: 	};
                    274: 
1.16      www       275: 
1.13      www       276:         for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
1.26      raeburn   277:             &status('Accepting connections');
                    278:             my $client = $server->accept()     or last;
1.37      bisitz    279:             &sync($command);
1.39      riegler   280:             print $command ("display2d:false;simp:true;kill(all);\n");
1.27      albertel  281: 	    &getmaximaoutput($command,2);
1.26      raeburn   282:             &sync($command);
                    283:             my $syntaxerr = 0;
                    284:             while (my $cmd=<$client>) {
                    285:                 &status('Processing command');
                    286:                 print $command &unescape($cmd);
                    287:                 my ($reply,$syntaxerr) = &getmaximaoutput($command,1);
                    288:                 print $client &escape($reply)."\n";
                    289:                 if ($syntaxerr) {
                    290:                     last;
                    291:                 } elsif ($reply=~/^Error\:/) {
                    292:                     &logthis('Died through '.$reply);
1.35      albertel  293: 		    kill('USR1' => $ppid);
1.26      raeburn   294:                     $client->close();
                    295:                     $command->hard_close();     
                    296:                     exit;
                    297:                 }
                    298: 	        &sync($command);
                    299:                 &status('Waiting for commands');
                    300:             }
1.13      www       301:         }
1.4       albertel  302: 
1.35      albertel  303: 	kill('USR1' => $ppid);
1.34      albertel  304: 	print $command ("quit();\n");
1.12      www       305:         # tidy up gracefully and finish
1.36      albertel  306: 	sleep(15);
1.16      www       307:         $command->soft_close();
1.1       www       308: 
1.2       www       309:         # this exit is VERY important, otherwise the child will become
                    310:         # a producer of more and more children, forking yourself into
                    311:         # process death.
                    312:         exit;
                    313:     }
                    314: }
1.4       albertel  315: 
1.18      www       316: {
                    317:     my $counter;
                    318:     sub sync {
                    319: 	my ($command)=@_;
                    320: 	$counter++;
                    321: 	my $expect=$counter.time;
                    322: 	print $command "$expect;\n";
                    323: 	while (1) {
1.25      raeburn   324: 	    my $output=&getmaximaoutput($command,1);
1.18      www       325: 	    if (($output=~/\Q$expect\E/) || ($output=~/^Error\:/)) {
                    326: 		return;
                    327: 	    }
                    328: 	}
                    329:     }
                    330: }
                    331: 
1.16      www       332: sub getmaximaoutput {
1.25      raeburn   333:     my ($command,$numcheck)=@_;
                    334:     my $regexp = '\(\%i\d+\)';
1.26      raeburn   335:     my $syntaxerr=0;
1.25      raeburn   336:     if ($numcheck) {
1.27      albertel  337:        	if ($numcheck eq 2) {
                    338: 	    # command was the killall so should get a full reset on
                    339: 	    # command numbers
1.41      droeschl  340: 	    $regexp = '(\(\%i(1)\)|[Ii]ncorrect syntax\:)';
1.27      albertel  341: 	} elsif ($command->match() =~ /\(\%i(\d+)\)/) {
1.25      raeburn   342:             my $nextmatch = $1+1;
1.41      droeschl  343:             $regexp = '(\(\%i'.$nextmatch.'\)|[Ii]ncorrect syntax\:)';
1.26      raeburn   344:         }
                    345:     }
                    346:     my $timeout = 20;
1.27      albertel  347:     my (undef,$error,$matched,$output) =
                    348: 	$command->expect($timeout, -re => $regexp);
                    349: 
1.41      droeschl  350:     if ($numcheck && lc($matched) eq 'incorrect syntax:') {
1.27      albertel  351: 	$syntaxerr = 1;
                    352: 	if (wantarray) {
                    353: 	    return ($matched,$syntaxerr);
                    354: 	} else {
                    355: 	    return $matched;
                    356: 	}
1.25      raeburn   357:     }
1.17      www       358:     if ($error) {
1.27      albertel  359: 	return 'Error: '.$error;
1.17      www       360:     }
1.40      www       361:     $output =~ s/\r+//gs; # Remove Windows-style linebreaks
1.16      www       362:     my $foundoutput=0;
1.32      albertel  363:     my $found_label=0;
1.16      www       364:     my $realoutput='';
                    365:     foreach my $line (split(/\n/,$output)) {
                    366:        if ($line=~/\;/) { $foundoutput=1; next; }
                    367:        if (!$foundoutput) { next; }
1.41      droeschl  368:        if ($line=~/^[Ii]ncorrect syntax:/) { $syntaxerr = 1; next; }
1.32      albertel  369:        if ($line=~ /^(\(\%o\d+\))(.+)$/){
1.31      bisitz    370:            my $label = $1;
                    371:            $line = $2;
                    372:            $label =~s/\S/ /g;
1.26      raeburn   373:            $line=$label.$line;
1.32      albertel  374: 	   $found_label=1;
                    375:        }
                    376:        if ($found_label) {
                    377: 	   $realoutput.=$line."\n";
1.16      www       378:        }
                    379:     }
1.23      raeburn   380:     if (wantarray) {
1.26      raeburn   381:         return ($realoutput,$syntaxerr);
1.23      raeburn   382:     } else {
                    383:         return $realoutput;
                    384:     }
1.15      www       385: }

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