Annotation of loncom/lonr, revision 1.1

1.1     ! www         1: #!/usr/bin/perl
        !             2: #
        !             3: # The LearningOnline Network with CAPA
        !             4: # Connect to MAXIMA CAS
        !             5: #
        !             6: # $Id: $
        !             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: #
        !            32: 
        !            33: use Expect; 
        !            34: use IO::Select;
        !            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:  
        !            42: use strict;
        !            43: 
        !            44: # global variables
        !            45: my $PREFORK                = 5;        # number of children to maintain
        !            46: my $MAX_CLIENTS_PER_CHILD  = 50;       # number of clients each child should process
        !            47: my $extra_children         = 0;
        !            48: my %children               = ();       # keys are current child process IDs
        !            49: my $children               = 0;        # current number of children
        !            50: my $status;                            # string for current status
        !            51: my $pidfile;                           # file containg parent process pid
        !            52: my $port;                              # path to UNIX socket file
        !            53: my %perlvar;                           # configuration file info
        !            54: my $lastlog;                           # last string that was logged
        !            55: 
        !            56: use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children $status
        !            57: 	    $pidfile $port %perlvar $lastlog);
        !            58:  
        !            59: # ------------------------------------------------------------ Service routines 
        !            60: sub REAPER {                        # takes care of dead children 
        !            61:                                     # and R processes
        !            62:     $SIG{CHLD} = \&REAPER;
        !            63:     my $pid = wait;
        !            64:     if (exists($children{$pid})) {
        !            65: 	$children--;
        !            66: 	delete($children{$pid});
        !            67: 	if ($extra_children) {
        !            68: 	    $extra_children--;
        !            69: 	}
        !            70:     }    
        !            71: }
        !            72:  
        !            73: sub HUNTSMAN {                      # signal handler for SIGINT
        !            74:     local($SIG{CHLD}) = 'IGNORE';   # we're going to kill our children
        !            75:     kill('INT' => keys(%children));
        !            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 {
        !            87:     my ($message)=@_;
        !            88:     my $execdir=$perlvar{'lonDaemons'};
        !            89:     my $fh=IO::File->new(">>$execdir/logs/lonr.log");
        !            90:     my $now=time;
        !            91:     my $local=localtime($now);
        !            92:     $lastlog=$local.': '.$message;
        !            93:     print $fh "$local ($$): $message\n";
        !            94: }
        !            95:  
        !            96: # -------------------------------------------------------------- Status setting
        !            97:  
        !            98: sub status {
        !            99:     my ($what)=@_;
        !           100:     my $now=time;
        !           101:     my $local=localtime($now);
        !           102:     $status=$local.': '.$what;
        !           103:     $0='lonr: '.$what.' '.$local;
        !           104: }
        !           105:  
        !           106: # -------------------------------------------------------- Escape Special Chars
        !           107:  
        !           108: sub escape {
        !           109:     my ($str)=@_;
        !           110:     $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
        !           111:     return $str;
        !           112: }
        !           113:  
        !           114: # ----------------------------------------------------- Un-Escape Special Chars
        !           115:  
        !           116: sub unescape {
        !           117:     my ($str)=@_;
        !           118:     $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
        !           119:     return $str;
        !           120: }
        !           121:  
        !           122: # ------------------------ grabs exception and records it to log before exiting
        !           123: sub catchexception {
        !           124:     my ($signal)=@_;
        !           125:     $SIG{QUIT}='DEFAULT';
        !           126:     $SIG{__DIE__}='DEFAULT';
        !           127:     chomp($signal);
        !           128:     &logthis("<font color=\"red\">CRITICAL: "
        !           129: 	     ."ABNORMAL EXIT. Child $$ died through "
        !           130: 	     ."\"$signal\"</font>");
        !           131:     die("Signal abend");
        !           132: }
        !           133: 
        !           134: 
        !           135: sub child_announce_death {
        !           136:     $SIG{USR1} = \&child_announce_death;
        !           137:     if ($extra_children < $PREFORK*10) {
        !           138: 	$extra_children++;
        !           139:     }
        !           140: }
        !           141: 
        !           142: # ---------------------------------------------------------------- Main program
        !           143: # -------------------------------- Set signal handlers to record abnormal exits
        !           144:  
        !           145:  
        !           146: $SIG{'QUIT'}=\&catchexception;
        !           147: $SIG{__DIE__}=\&catchexception;
        !           148: $SIG{USR1} = \&child_announce_death;
        !           149:  
        !           150: # ---------------------------------- Read loncapa_apache.conf and loncapa.conf
        !           151: &status("Read loncapa.conf and loncapa_apache.conf");
        !           152: %perlvar=%{&LONCAPA::Configuration::read_conf('loncapa.conf')};
        !           153:  
        !           154: # ----------------------------- Make sure this process is running from user=www
        !           155: my $wwwid=getpwnam('www');
        !           156: if ($wwwid!=$<) {
        !           157:     my $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
        !           158:     my $subj="LON: User ID mismatch";
        !           159:     system("echo 'User ID mismatch.  lonr must be run as user www.' |\
        !           160:  mailto $emailto -s '$subj' > /dev/null");
        !           161:     exit 1;
        !           162: }
        !           163:  
        !           164: # --------------------------------------------- Check if other instance running
        !           165:  
        !           166: $pidfile="$perlvar{'lonDaemons'}/logs/lonr.pid";
        !           167:  
        !           168: if (-e $pidfile) {
        !           169:     my $lfh=IO::File->new("$pidfile");
        !           170:     my $pide=<$lfh>;
        !           171:     chomp($pide);
        !           172:     if (kill(0 => $pide)) { die "already running"; }
        !           173: }
        !           174: 
        !           175: # ------------------------------------------------------- Listen to UNIX socket
        !           176: &status("Opening socket");
        !           177:  
        !           178: $port = "$perlvar{'lonSockDir'}/rsock";
        !           179:  
        !           180: unlink($port);
        !           181:  
        !           182: 
        !           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: }
        !           195:     
        !           196:  
        !           197: # ---------------------------------------------------- Fork once and dissociate
        !           198:  
        !           199: my $fpid=fork;
        !           200: exit if $fpid;
        !           201: die("Couldn't fork: $!") unless defined($fpid);
        !           202:  
        !           203: POSIX::setsid() or die "Can't start new session: $!";
        !           204:  
        !           205: # ------------------------------------------------------- Write our PID on disk
        !           206:  
        !           207: my $execdir=$perlvar{'lonDaemons'};
        !           208: open(PIDSAVE,">$execdir/logs/lonr.pid");
        !           209: print PIDSAVE "$$\n";
        !           210: close(PIDSAVE);
        !           211: &logthis("<font color='red'>CRITICAL: ---------- Starting ----------</font>");
        !           212: &status('Starting');
        !           213:      
        !           214: 
        !           215: # Install signal handlers.
        !           216: $SIG{CHLD} = \&REAPER;
        !           217: $SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
        !           218:  
        !           219: # Fork off our children.
        !           220: for (1 .. $PREFORK) {
        !           221:     &make_new_child($server);
        !           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)
        !           228:     for (my $i = $children; $i < $PREFORK+$extra_children; $i++) {
        !           229:         &status('Parent process, starting child');
        !           230:         &make_new_child($server);           # top up the child pool
        !           231:     }
        !           232: }
        !           233:                                                                                 
        !           234: sub make_new_child {
        !           235:     my ($server) = @_;
        !           236: 
        !           237:     # block signal for fork
        !           238:     my $sigset = POSIX::SigSet->new(SIGINT);
        !           239:     sigprocmask(SIG_BLOCK, $sigset)
        !           240:         or die("Can't block SIGINT for fork: $!\n");
        !           241:      
        !           242:     die("fork: $!") unless defined(my $pid = fork);
        !           243:      
        !           244:     if ($pid) {
        !           245:         # Parent records the child's birth and returns.
        !           246:         sigprocmask(SIG_UNBLOCK, $sigset)
        !           247:             or die("Can't unblock SIGINT for fork: $!\n");
        !           248:         $children{$pid} = 1;
        !           249:         $children++;
        !           250:         return;
        !           251:     } else {
        !           252:         # Child can *not* return from this subroutine.
        !           253:         
        !           254: 	my $ppid = getppid();
        !           255:      
        !           256:         # unblock signals
        !           257:         sigprocmask(SIG_UNBLOCK, $sigset)
        !           258:             or die("Can't unblock SIGINT for fork: $!\n");
        !           259: 
        !           260:         &logthis('New process started');
        !           261: 
        !           262:         my $command=Expect->spawn('R --vanilla');
        !           263: 	# soft/hard_close can take awhile and we really
        !           264:         # don't care we just want it gone
        !           265: 	$SIG{INT} = sub {
        !           266: 	    my $pid = $command->pid();
        !           267: 	    kill('KILL'=>$pid);
        !           268: 	    exit; 
        !           269: 	};
        !           270: 
        !           271: 	$command->log_stdout(0);
        !           272: 	$command->log_file("$execdir/logs/lonr.session.log");
        !           273: 
        !           274:         for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
        !           275:             &status('Accepting connections');
        !           276:             my $client = $server->accept()     or last;
        !           277:             &sync($command);
        !           278: #            print $command ("display2d:false;simp:true;kill(all);\n");
        !           279: #	    &getroutput($command,2);
        !           280: #            &sync($command);
        !           281:             my $syntaxerr = 0;
        !           282:             while (my $cmd=<$client>) {
        !           283:                 &status('Processing command');
        !           284:                 print $command &unescape($cmd);
        !           285:                 my ($reply,$syntaxerr) = &getroutput($command,1);
        !           286:                 print $client &escape($reply)."\n";
        !           287:                 if ($syntaxerr) {
        !           288:                     last;
        !           289:                 } elsif ($reply=~/^Error\:/) {
        !           290:                     &logthis('Died through '.$reply);
        !           291: 		    kill('USR1' => $ppid);
        !           292:                     $client->close();
        !           293:                     $command->hard_close();     
        !           294:                     exit;
        !           295:                 }
        !           296: 	        &sync($command);
        !           297:                 &status('Waiting for commands');
        !           298:             }
        !           299:         }
        !           300: 
        !           301: 	kill('USR1' => $ppid);
        !           302: 	print $command ("q();\n");
        !           303:         # tidy up gracefully and finish
        !           304: 	sleep(15);
        !           305:         $command->soft_close();
        !           306: 
        !           307:         # this exit is VERY important, otherwise the child will become
        !           308:         # a producer of more and more children, forking yourself into
        !           309:         # process death.
        !           310:         exit;
        !           311:     }
        !           312: }
        !           313: 
        !           314: {
        !           315:     my $counter;
        !           316:     sub sync {
        !           317: 	my ($command)=@_;
        !           318: 	$counter++;
        !           319: 	my $expect=$counter.time;
        !           320: 	print $command "$expect;\n";
        !           321: 	while (1) {
        !           322: 	    my $output=&getroutput($command);
        !           323: 	    if (($output=~/\Q$expect\E/) || ($output=~/^Error\:/)) {
        !           324: 		return;
        !           325: 	    }
        !           326: 	}
        !           327:     }
        !           328: }
        !           329: 
        !           330: sub getroutput {
        !           331:     my ($command)=@_;
        !           332:     my $regexp = '>';
        !           333:     my $syntaxerr=0;
        !           334:     my $timeout = 20;
        !           335:     my (undef,$error,$matched,$output) =
        !           336: 	$command->expect($timeout, -re => $regexp);
        !           337:     if ($matched eq 'Incorrect syntax:') {
        !           338: 	$syntaxerr = 1;
        !           339: 	if (wantarray) {
        !           340: 	    return ($matched,$syntaxerr);
        !           341: 	} else {
        !           342: 	    return $matched;
        !           343: 	}
        !           344:     }
        !           345:     if ($error) {
        !           346: 	return 'Error: '.$error;
        !           347:     }
        !           348: 
        !           349:     my $foundoutput=0;
        !           350:     my $found_label=0;
        !           351:     my $realoutput='';
        !           352:     foreach my $line (split(/\n/,$output)) {
        !           353:        $line=~s/\s$//gs;
        !           354:        if (my ($result)=($line=~/^\[\d+\,*\]\s*(.*)/)) { $realoutput.=$result."\n"; }
        !           355:     }
        !           356:     if (wantarray) {
        !           357:         return ($realoutput,$syntaxerr);
        !           358:     } else {
        !           359:         return $realoutput;
        !           360:     }
        !           361: }

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