Annotation of loncom/lonmaxima, revision 1.44
1.1 www 1: #!/usr/bin/perl
2: #
3: # The LearningOnline Network with CAPA
4: # Connect to MAXIMA CAS
5: #
1.44 ! raeburn 6: # $Id: lonmaxima,v 1.43 2018/10/29 02:57:30 raeburn 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 $subj="LON: User ID mismatch";
1.43 raeburn 159: system("echo 'User ID mismatch. lonmaxima must be run as user www.' |".
1.44 ! raeburn 160: " mail -s '$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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