Annotation of loncom/lonmaxima, revision 1.35

1.1       www         1: #!/usr/bin/perl
                      2: #
                      3: # The LearningOnline Network with CAPA
                      4: # Connect to MAXIMA CAS
                      5: #
1.34      albertel    6: # $Id: lonmaxima,v 1.33 2007/08/31 23:19:54 albertel 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;
        !           137:     $extra_children++;
        !           138: }
1.16      www       139: 
1.2       www       140: # ---------------------------------------------------------------- Main program
                    141: # -------------------------------- Set signal handlers to record abnormal exits
                    142:  
                    143:  
                    144: $SIG{'QUIT'}=\&catchexception;
                    145: $SIG{__DIE__}=\&catchexception;
1.35    ! albertel  146: $SIG{USR1} = \&child_announce_death;
1.2       www       147:  
                    148: # ---------------------------------- Read loncapa_apache.conf and loncapa.conf
                    149: &status("Read loncapa.conf and loncapa_apache.conf");
1.3       albertel  150: %perlvar=%{&LONCAPA::Configuration::read_conf('loncapa.conf')};
1.2       www       151:  
                    152: # ----------------------------- Make sure this process is running from user=www
                    153: my $wwwid=getpwnam('www');
                    154: if ($wwwid!=$<) {
1.5       albertel  155:     my $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
                    156:     my $subj="LON: User ID mismatch";
                    157:     system("echo 'User ID mismatch.  lonmaxima must be run as user www.' |\
1.2       www       158:  mailto $emailto -s '$subj' > /dev/null");
1.5       albertel  159:     exit 1;
1.2       www       160: }
                    161:  
                    162: # --------------------------------------------- Check if other instance running
                    163:  
                    164: $pidfile="$perlvar{'lonDaemons'}/logs/lonmaxima.pid";
                    165:  
                    166: if (-e $pidfile) {
1.5       albertel  167:     my $lfh=IO::File->new("$pidfile");
                    168:     my $pide=<$lfh>;
                    169:     chomp($pide);
1.6       albertel  170:     if (kill(0 => $pide)) { die "already running"; }
1.2       www       171: }
1.5       albertel  172: 
1.2       www       173: # ------------------------------------------------------- Listen to UNIX socket
                    174: &status("Opening socket");
                    175:  
                    176: $port = "$perlvar{'lonSockDir'}/maximasock";
                    177:  
                    178: unlink($port);
                    179:  
                    180: 
1.6       albertel  181: my $server = IO::Socket::UNIX->new(Local  => $port,
                    182: 				   Type   => SOCK_STREAM,
                    183: 				   Listen => 10 );
                    184: if (!$server) {
                    185:     my $st=120+int(rand(240));
                    186: 
                    187:     &logthis("<font color=blue>WARNING: ".
                    188: 	     "Can't make server socket ($st secs):  .. exiting</font>");
                    189: 
                    190:     sleep($st);
                    191:     exit;
                    192: }
1.2       www       193:     
                    194:  
                    195: # ---------------------------------------------------- Fork once and dissociate
                    196:  
                    197: my $fpid=fork;
                    198: exit if $fpid;
1.6       albertel  199: die("Couldn't fork: $!") unless defined($fpid);
1.2       www       200:  
                    201: POSIX::setsid() or die "Can't start new session: $!";
                    202:  
                    203: # ------------------------------------------------------- Write our PID on disk
                    204:  
                    205: my $execdir=$perlvar{'lonDaemons'};
1.5       albertel  206: open(PIDSAVE,">$execdir/logs/lonmaxima.pid");
1.2       www       207: print PIDSAVE "$$\n";
                    208: close(PIDSAVE);
                    209: &logthis("<font color='red'>CRITICAL: ---------- Starting ----------</font>");
                    210: &status('Starting');
1.6       albertel  211:      
1.2       www       212: 
1.10      albertel  213: # Install signal handlers.
                    214: $SIG{CHLD} = \&REAPER;
                    215: $SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
1.16      www       216:  
1.2       www       217: # Fork off our children.
                    218: for (1 .. $PREFORK) {
1.16      www       219:     &make_new_child($server);
1.2       www       220: }
                    221:  
                    222: # And maintain the population.
                    223: while (1) {
                    224:     &status('Parent process, sleeping');
                    225:     sleep;                          # wait for a signal (i.e., child's death)
1.35    ! albertel  226:     for (my $i = $children; $i < $PREFORK+$extra_children; $i++) {
1.2       www       227:         &status('Parent process, starting child');
1.16      www       228:         &make_new_child($server);           # top up the child pool
1.2       www       229:     }
                    230: }
                    231:                                                                                 
                    232: sub make_new_child {
1.16      www       233:     my ($server) = @_;
1.4       albertel  234: 
1.2       www       235:     # block signal for fork
1.4       albertel  236:     my $sigset = POSIX::SigSet->new(SIGINT);
1.2       www       237:     sigprocmask(SIG_BLOCK, $sigset)
1.6       albertel  238:         or die("Can't block SIGINT for fork: $!\n");
1.2       www       239:      
1.6       albertel  240:     die("fork: $!") unless defined(my $pid = fork);
1.2       www       241:      
                    242:     if ($pid) {
                    243:         # Parent records the child's birth and returns.
                    244:         sigprocmask(SIG_UNBLOCK, $sigset)
1.6       albertel  245:             or die("Can't unblock SIGINT for fork: $!\n");
1.16      www       246:         $children{$pid} = 1;
1.2       www       247:         $children++;
                    248:         return;
                    249:     } else {
                    250:         # Child can *not* return from this subroutine.
1.30      albertel  251:         
1.35    ! albertel  252: 	my $ppid = getppid();
1.2       www       253:      
                    254:         # unblock signals
                    255:         sigprocmask(SIG_UNBLOCK, $sigset)
1.6       albertel  256:             or die("Can't unblock SIGINT for fork: $!\n");
1.15      www       257: 
1.17      www       258:         &logthis('New process started');
                    259: 
1.16      www       260:         my $command=Expect->spawn('maxima');
1.30      albertel  261: 	# soft/hard_close can take awhile and we really
                    262:         # don't care we just want it gone
                    263: 	$SIG{INT} = sub {
                    264: 	    my $pid = $command->pid();
                    265: 	    kill('KILL'=>$pid);
                    266: 	    exit; 
                    267: 	};
                    268: 
                    269: 	$command->log_stdout(0);
1.27      albertel  270: 	#$command->log_file("$execdir/logs/lonmaxima.session.log");
1.33      albertel  271:         &sync($command);
1.16      www       272: 
1.13      www       273:         for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
1.26      raeburn   274:             &status('Accepting connections');
                    275:             my $client = $server->accept()     or last;
1.29      www       276:             print $command ("display2d:false;kill(all);\n");
1.27      albertel  277: 	    &getmaximaoutput($command,2);
1.26      raeburn   278:             &sync($command);
                    279:             my $syntaxerr = 0;
                    280:             while (my $cmd=<$client>) {
                    281:                 &status('Processing command');
                    282:                 print $command &unescape($cmd);
                    283:                 my ($reply,$syntaxerr) = &getmaximaoutput($command,1);
                    284:                 print $client &escape($reply)."\n";
                    285:                 if ($syntaxerr) {
                    286:                     last;
                    287:                 } elsif ($reply=~/^Error\:/) {
                    288:                     &logthis('Died through '.$reply);
1.35    ! albertel  289: 		    kill('USR1' => $ppid);
1.26      raeburn   290:                     $client->close();
                    291:                     $command->hard_close();     
                    292:                     exit;
                    293:                 }
                    294: 	        &sync($command);
                    295:                 &status('Waiting for commands');
                    296:             }
1.13      www       297:         }
1.4       albertel  298: 
1.35    ! albertel  299: 	kill('USR1' => $ppid);
1.34      albertel  300: 	print $command ("quit();\n");
1.12      www       301:         # tidy up gracefully and finish
1.4       albertel  302: 
1.16      www       303:         $command->soft_close();
1.1       www       304: 
1.2       www       305:         # this exit is VERY important, otherwise the child will become
                    306:         # a producer of more and more children, forking yourself into
                    307:         # process death.
                    308:         exit;
                    309:     }
                    310: }
1.4       albertel  311: 
1.18      www       312: {
                    313:     my $counter;
                    314:     sub sync {
                    315: 	my ($command)=@_;
                    316: 	$counter++;
                    317: 	my $expect=$counter.time;
                    318: 	print $command "$expect;\n";
                    319: 	while (1) {
1.25      raeburn   320: 	    my $output=&getmaximaoutput($command,1);
1.18      www       321: 	    if (($output=~/\Q$expect\E/) || ($output=~/^Error\:/)) {
                    322: 		return;
                    323: 	    }
                    324: 	}
                    325:     }
                    326: }
                    327: 
1.16      www       328: sub getmaximaoutput {
1.25      raeburn   329:     my ($command,$numcheck)=@_;
                    330:     my $regexp = '\(\%i\d+\)';
1.26      raeburn   331:     my $syntaxerr=0;
1.25      raeburn   332:     if ($numcheck) {
1.27      albertel  333:        	if ($numcheck eq 2) {
                    334: 	    # command was the killall so should get a full reset on
                    335: 	    # command numbers
                    336: 	    $regexp = '(\(\%i(1)\)|Incorrect syntax\:)';
                    337: 	} elsif ($command->match() =~ /\(\%i(\d+)\)/) {
1.25      raeburn   338:             my $nextmatch = $1+1;
1.26      raeburn   339:             $regexp = '(\(\%i'.$nextmatch.'\)|Incorrect syntax\:)';
                    340:         }
                    341:     }
                    342:     my $timeout = 20;
1.27      albertel  343:     my (undef,$error,$matched,$output) =
                    344: 	$command->expect($timeout, -re => $regexp);
                    345: 
                    346:     if ($numcheck && $matched eq 'Incorrect syntax:') {
                    347: 	$syntaxerr = 1;
                    348: 	if (wantarray) {
                    349: 	    return ($matched,$syntaxerr);
                    350: 	} else {
                    351: 	    return $matched;
                    352: 	}
1.25      raeburn   353:     }
1.17      www       354:     if ($error) {
1.27      albertel  355: 	return 'Error: '.$error;
1.17      www       356:     }
1.23      raeburn   357:     $output =~ s/\r+//g; # Remove Windows-style linebreaks
1.16      www       358:     my $foundoutput=0;
1.32      albertel  359:     my $found_label=0;
1.16      www       360:     my $realoutput='';
                    361:     foreach my $line (split(/\n/,$output)) {
                    362:        if ($line=~/\;/) { $foundoutput=1; next; }
                    363:        if (!$foundoutput) { next; }
1.23      raeburn   364:        if ($line=~/^Incorrect syntax:/) { $syntaxerr = 1; next; }
1.32      albertel  365:        if ($line=~ /^(\(\%o\d+\))(.+)$/){
1.31      bisitz    366:            my $label = $1;
                    367:            $line = $2;
                    368:            $label =~s/\S/ /g;
1.26      raeburn   369:            $line=$label.$line;
1.32      albertel  370: 	   $found_label=1;
                    371:        }
                    372:        if ($found_label) {
                    373: 	   $realoutput.=$line."\n";
1.16      www       374:        }
                    375:     }
1.23      raeburn   376:     if (wantarray) {
1.26      raeburn   377:         return ($realoutput,$syntaxerr);
1.23      raeburn   378:     } else {
                    379:         return $realoutput;
                    380:     }
1.15      www       381: }

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