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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