1: #!/usr/bin/perl
2: #
3: # The LearningOnline Network with CAPA
4: # Connect to R CAS
5: #
6: # $Id: lonr,v 1.11 2014/11/16 17:41:53 raeburn Exp $
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 $command ("library(phpSerialize);\n");
279: &getroutput($command);
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);
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 $digits = length($counter);
320: if ($digits > 10) {
321: $counter = 1;
322: }
323: my $expect=$counter;
324: print $command "print($expect,digits=$digits);\n";
325: while (1) {
326: my $output=&getroutput($command);
327: chomp($output);
328: if (($output=~/^\Q$expect\E/) || ($output=~/^Error\:/)) {
329: return;
330: }
331: }
332: }
333: }
334:
335: sub getroutput {
336: my ($command)=@_;
337: my $regexp = '>\s+$';
338: my $syntaxerr=0;
339: my $timeout = 20;
340: my (undef,$error,$matched,$output) =
341: $command->expect($timeout, -re => $regexp);
342: if ($matched eq 'Incorrect syntax:') {
343: $syntaxerr = 1;
344: if (wantarray) {
345: return ($matched,$syntaxerr);
346: } else {
347: return $matched;
348: }
349: }
350: if ($error) {
351: return 'Error: '.$error;
352: }
353:
354: #
355: # Extract data from lines returned by R:
356: # including: (a) indexed output, e.g., line starts with [1] etc. (index excluded)
357: # (b) support for legacy use of &cas("R") to retreve matrix and data.frame
358: # i.e., unserialized data, in which lines may begin [1,] or 1
359: # respectively. The approved method for retrieving these types of
360: # data is to use &cas_hashref(), which uses phpSerialize() to
361: # serialize the output (thereby eliminating the need for the second
362: # regexp in the "elsif" when looping over the lines of output.
363: # excluding: echo of actual (final) expression originally passed to R excluded by
364: # checking for trailing semicolon.
365: #
366:
367: my $realoutput='';
368: foreach my $line (split(/\n/,$output)) {
369: $line=~s/\s$//gs;
370: if ($line=~/^Error\:/) { $syntaxerr=1; next; }
371: if (my ($result)=($line=~/^\s*\[\d+\]\s*(.*)/)) {
372: $realoutput.=$result."\n";
373: } elsif (($line !~ /\;$/) && (my ($result)=($line=~/^(?:\[\d+\,\]|\d+)\s*(.*)/))) {
374: $realoutput.=$result."\n";
375: }
376: }
377: if (wantarray) {
378: return ($realoutput,$syntaxerr);
379: } else {
380: return $realoutput;
381: }
382: }
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