1: #!/usr/bin/perl
2:
3: # The LearningOnline Network
4: # lonc - LON TCP-Client Domain-Socket-Server
5: # provides persistent TCP connections to the other servers in the network
6: # through multiplexed domain sockets
7: #
8: # $Id: lonc,v 1.22 2001/11/29 18:57:46 www Exp $
9: #
10: # Copyright Michigan State University Board of Trustees
11: #
12: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
13: #
14: # LON-CAPA is free software; you can redistribute it and/or modify
15: # it under the terms of the GNU General Public License as published by
16: # the Free Software Foundation; either version 2 of the License, or
17: # (at your option) any later version.
18: #
19: # LON-CAPA is distributed in the hope that it will be useful,
20: # but WITHOUT ANY WARRANTY; without even the implied warranty of
21: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22: # GNU General Public License for more details.
23: #
24: # You should have received a copy of the GNU General Public License
25: # along with LON-CAPA; if not, write to the Free Software
26: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
27: #
28: # /home/httpd/html/adm/gpl.txt
29: #
30: # http://www.lon-capa.org/
31: #
32: # PID in subdir logs/lonc.pid
33: # kill kills
34: # HUP restarts
35: # USR1 tries to open connections again
36:
37: # 6/4/99,6/5,6/7,6/8,6/9,6/10,6/11,6/12,7/14,7/19,
38: # 10/8,10/9,10/15,11/18,12/22,
39: # 2/8,7/25 Gerd Kortemeyer
40: # 12/05 Scott Harrison
41: # 12/05 Gerd Kortemeyer
42: # 01/10/01 Scott Harrison
43: # 03/14/01,03/15,06/12,11/26,11/27,11/28 Gerd Kortemeyer
44: #
45: # based on nonforker from Perl Cookbook
46: # - server who multiplexes without forking
47:
48: use POSIX;
49: use IO::Socket;
50: use IO::Select;
51: use IO::File;
52: use Socket;
53: use Fcntl;
54: use Tie::RefHash;
55: use Crypt::IDEA;
56:
57: my $status='';
58: my $lastlog='';
59:
60: # grabs exception and records it to log before exiting
61: sub catchexception {
62: my ($signal)=@_;
63: $SIG{'QUIT'}='DEFAULT';
64: $SIG{__DIE__}='DEFAULT';
65: &logthis("<font color=red>CRITICAL: "
66: ."ABNORMAL EXIT. Child $$ for server $wasserver died through "
67: ."\"$signal\" with this parameter->[$@]</font>");
68: die($@);
69: }
70:
71: $childmaxattempts=5;
72:
73: # -------------------------------- Set signal handlers to record abnormal exits
74:
75: $SIG{'QUIT'}=\&catchexception;
76: $SIG{__DIE__}=\&catchexception;
77:
78: # ------------------------------------ Read httpd access.conf and get variables
79:
80: open (CONFIG,"/etc/httpd/conf/access.conf") || die "Can't read access.conf";
81:
82: while ($configline=<CONFIG>) {
83: if ($configline =~ /PerlSetVar/) {
84: my ($dummy,$varname,$varvalue)=split(/\s+/,$configline);
85: chomp($varvalue);
86: $perlvar{$varname}=$varvalue;
87: }
88: }
89: close(CONFIG);
90:
91: # ----------------------------- Make sure this process is running from user=www
92: my $wwwid=getpwnam('www');
93: if ($wwwid!=$<) {
94: $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
95: $subj="LON: $perlvar{'lonHostID'} User ID mismatch";
96: system("echo 'User ID mismatch. lonc must be run as user www.' |\
97: mailto $emailto -s '$subj' > /dev/null");
98: exit 1;
99: }
100:
101: # --------------------------------------------- Check if other instance running
102:
103: my $pidfile="$perlvar{'lonDaemons'}/logs/lonc.pid";
104:
105: if (-e $pidfile) {
106: my $lfh=IO::File->new("$pidfile");
107: my $pide=<$lfh>;
108: chomp($pide);
109: if (kill 0 => $pide) { die "already running"; }
110: }
111:
112: # ------------------------------------------------------------- Read hosts file
113:
114: open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
115:
116: while ($configline=<CONFIG>) {
117: my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
118: chomp($ip);
119: $hostip{$id}=$ip;
120: }
121: close(CONFIG);
122:
123: # -------------------------------------------------------- Routines for forking
124:
125: %children = (); # keys are current child process IDs,
126: # values are hosts
127: %childpid = (); # the other way around
128:
129: %childatt = (); # number of attempts to start server
130: # for ID
131:
132: sub REAPER { # takes care of dead children
133: $SIG{CHLD} = \&REAPER;
134: my $pid = wait;
135: my $wasserver=$children{$pid};
136: &logthis("<font color=red>CRITICAL: "
137: ."Child $pid for server $wasserver died ($childatt{$wasserver})</font>");
138: delete $children{$pid};
139: delete $childpid{$wasserver};
140: my $port = "$perlvar{'lonSockDir'}/$wasserver";
141: unlink($port);
142: }
143:
144: sub HUNTSMAN { # signal handler for SIGINT
145: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
146: map {
147: $wasserver=$children{$_};
148: &status("Closing $wasserver");
149: &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
150: &status("Kill PID $_ for $wasserver");
151: kill ('INT',$_);
152: } keys %children;
153: my $execdir=$perlvar{'lonDaemons'};
154: unlink("$execdir/logs/lonc.pid");
155: &logthis("<font color=red>CRITICAL: Shutting down</font>");
156: exit; # clean up with dignity
157: }
158:
159: sub HUPSMAN { # signal handler for SIGHUP
160: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
161: map {
162: $wasserver=$children{$_};
163: &status("Closing $wasserver");
164: &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
165: &status("Kill PID $_ for $wasserver");
166: kill ('INT',$_);
167: } keys %children;
168: &logthis("<font color=red>CRITICAL: Restarting</font>");
169: unlink("$execdir/logs/lonc.pid");
170: my $execdir=$perlvar{'lonDaemons'};
171: exec("$execdir/lonc"); # here we go again
172: }
173:
174: sub checkchildren {
175: &initnewstatus();
176: &logstatus();
177: &logthis('Going to check on the children');
178: map {
179: sleep 1;
180: unless (kill 'USR1' => $_) {
181: &logthis ('Child '.$_.' is dead');
182: &logstatus($$.' is dead');
183: }
184: } sort keys %children;
185: }
186:
187: sub USRMAN {
188: &logthis("USR1: Trying to establish connections again");
189: foreach $thisserver (keys %hostip) {
190: $answer=subreply("ping",$thisserver);
191: &logthis("USR1: Ping $thisserver "
192: ."(pid >$childpid{$thisserver}<, $childatt{thisserver} attempts): "
193: ." >$answer<");
194: }
195: %childatt=();
196: &checkchildren();
197: }
198:
199: # -------------------------------------------------- Non-critical communication
200: sub subreply {
201: my ($cmd,$server)=@_;
202: my $answer='';
203: if ($server ne $perlvar{'lonHostID'}) {
204: my $peerfile="$perlvar{'lonSockDir'}/$server";
205: my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
206: Type => SOCK_STREAM,
207: Timeout => 10)
208: or return "con_lost";
209:
210:
211: $SIG{ALRM}=sub { die "timeout" };
212: $SIG{__DIE__}='DEFAULT';
213: eval {
214: alarm(10);
215: print $sclient "$cmd\n";
216: $answer=<$sclient>;
217: chomp($answer);
218: alarm(0);
219: };
220: if ((!$answer) || ($@=~/timeout/)) { $answer="con_lost"; }
221: $SIG{ALRM}='DEFAULT';
222: $SIG{__DIE__}=\&catchexception;
223: } else { $answer='self_reply'; }
224: return $answer;
225: }
226:
227: # --------------------------------------------------------------------- Logging
228:
229: sub logthis {
230: my $message=shift;
231: my $execdir=$perlvar{'lonDaemons'};
232: my $fh=IO::File->new(">>$execdir/logs/lonc.log");
233: my $now=time;
234: my $local=localtime($now);
235: $lastlog=$local.': '.$message;
236: print $fh "$local ($$): $message\n";
237: }
238:
239:
240: sub logperm {
241: my $message=shift;
242: my $execdir=$perlvar{'lonDaemons'};
243: my $now=time;
244: my $local=localtime($now);
245: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
246: print $fh "$now:$message:$local\n";
247: }
248: # ------------------------------------------------------------------ Log status
249:
250: sub logstatus {
251: my $docdir=$perlvar{'lonDocRoot'};
252: my $fh=IO::File->new(">>$docdir/lon-status/loncstatus.txt");
253: print $fh $$."\t".$status."\t".$lastlog."\n";
254: }
255:
256: sub initnewstatus {
257: my $docdir=$perlvar{'lonDocRoot'};
258: my $fh=IO::File->new(">$docdir/lon-status/loncstatus.txt");
259: my $now=time;
260: my $local=localtime($now);
261: print $fh "LONC status $local - parent $$\n\n";
262: }
263:
264: # -------------------------------------------------------------- Status setting
265:
266: sub status {
267: my $what=shift;
268: my $now=time;
269: my $local=localtime($now);
270: $status=$local.': '.$what;
271: }
272:
273:
274: # ---------------------------------------------------- Fork once and dissociate
275:
276: $fpid=fork;
277: exit if $fpid;
278: die "Couldn't fork: $!" unless defined ($fpid);
279:
280: POSIX::setsid() or die "Can't start new session: $!";
281:
282: # ------------------------------------------------------- Write our PID on disk
283:
284: $execdir=$perlvar{'lonDaemons'};
285: open (PIDSAVE,">$execdir/logs/lonc.pid");
286: print PIDSAVE "$$\n";
287: close(PIDSAVE);
288: &logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
289:
290: # ----------------------------- Ignore signals generated during initial startup
291: $SIG{HUP}=$SIG{USR1}='IGNORE';
292: # ------------------------------------------------------- Now we are on our own
293:
294: # Fork off our children, one for every server
295:
296: &status("Forking ...");
297:
298: foreach $thisserver (keys %hostip) {
299: make_new_child($thisserver);
300: }
301:
302: &logthis("Done starting initial servers");
303: # ----------------------------------------------------- Install signal handlers
304:
305: $SIG{CHLD} = \&REAPER;
306: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
307: $SIG{HUP} = \&HUPSMAN;
308: $SIG{USR1} = \&USRMAN;
309:
310: # And maintain the population.
311: while (1) {
312: &status("Sleeping");
313: sleep; # wait for a signal (i.e., child's death)
314: # See who died and start new one
315: &status("Woke up");
316: foreach $thisserver (keys %hostip) {
317: if (!$childpid{$thisserver}) {
318: if ($childatt{$thisserver}<$childmaxattempts) {
319: $childatt{$thisserver}++;
320: &logthis(
321: "<font color=yellow>INFO: Trying to reconnect for $thisserver "
322: ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
323: make_new_child($thisserver);
324: }
325: }
326: }
327: }
328:
329:
330: sub make_new_child {
331:
332: my $conserver=shift;
333: my $pid;
334: my $sigset;
335: &logthis("Attempting to start child for server $conserver");
336: # block signal for fork
337: $sigset = POSIX::SigSet->new(SIGINT);
338: sigprocmask(SIG_BLOCK, $sigset)
339: or die "Can't block SIGINT for fork: $!\n";
340:
341: die "fork: $!" unless defined ($pid = fork);
342:
343: if ($pid) {
344: # Parent records the child's birth and returns.
345: sigprocmask(SIG_UNBLOCK, $sigset)
346: or die "Can't unblock SIGINT for fork: $!\n";
347: $children{$pid} = $conserver;
348: $childpid{$conserver} = $pid;
349: return;
350: } else {
351: # Child can *not* return from this subroutine.
352: $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
353: $SIG{USR1}= \&logstatus;
354:
355: # unblock signals
356: sigprocmask(SIG_UNBLOCK, $sigset)
357: or die "Can't unblock SIGINT for fork: $!\n";
358:
359: # ----------------------------- This is the modified main program of non-forker
360:
361: $port = "$perlvar{'lonSockDir'}/$conserver";
362:
363: unlink($port);
364:
365: # ---------------------------------------------------- Client to network server
366:
367: &status("Opening TCP: $conserver");
368:
369: unless (
370: $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
371: PeerPort => $perlvar{'londPort'},
372: Proto => "tcp",
373: Type => SOCK_STREAM)
374: ) {
375: my $st=120+int(rand(240));
376: &logthis(
377: "<font color=blue>WARNING: Couldn't connect $conserver ($st secs): $@</font>");
378: sleep($st);
379: exit;
380: };
381: # ----------------------------------------------------------------- Init dialog
382:
383: &status("Init dialogue: $conserver");
384:
385: $SIG{ALRM}=sub { die "timeout" };
386: $SIG{__DIE__}='DEFAULT';
387: eval {
388: alarm(60);
389: print $remotesock "init\n";
390: $answer=<$remotesock>;
391: print $remotesock "$answer";
392: $answer=<$remotesock>;
393: chomp($answer);
394: alarm(0);
395: };
396: $SIG{ALRM}='DEFAULT';
397: $SIG{__DIE__}=\&catchexception;
398:
399: if ($@=~/timeout/) {
400: &logthis("Timed out during init: $conserver");
401: exit;
402: }
403:
404:
405: &logthis("Init reply for $conserver: >$answer<");
406: if ($answer ne 'ok') {
407: my $st=120+int(rand(240));
408: &logthis(
409: "<font color=blue>WARNING: Init failed $conserver ($st secs)</font>");
410: sleep($st);
411: exit;
412: }
413: sleep 5;
414: &status("Ponging $conserver");
415: print $remotesock "pong\n";
416: $answer=<$remotesock>;
417: chomp($answer);
418: &logthis("Pong reply for $conserver: >$answer<");
419: # ----------------------------------------------------------- Initialize cipher
420:
421: &status("Initialize cipher: $conserver");
422: print $remotesock "ekey\n";
423: my $buildkey=<$remotesock>;
424: my $key=$conserver.$perlvar{'lonHostID'};
425: $key=~tr/a-z/A-Z/;
426: $key=~tr/G-P/0-9/;
427: $key=~tr/Q-Z/0-9/;
428: $key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
429: $key=substr($key,0,32);
430: my $cipherkey=pack("H32",$key);
431: if ($cipher=new IDEA $cipherkey) {
432: &logthis("Secure connection initialized: $conserver");
433: } else {
434: my $st=120+int(rand(240));
435: &logthis(
436: "<font color=blue>WARNING: ".
437: "Could not establish secure connection, $conserver ($st secs)!</font>");
438: sleep($st);
439: exit;
440: }
441:
442: # ----------------------------------------- We're online, send delayed messages
443: &status("Checking for delayed messages");
444: my @allbuffered;
445: my $path="$perlvar{'lonSockDir'}/delayed";
446: opendir(DIRHANDLE,$path);
447: @allbuffered=grep /\.$conserver$/, readdir DIRHANDLE;
448: closedir(DIRHANDLE);
449: my $dfname;
450: map {
451: &status("Sending delayed $conserver $_");
452: $dfname="$path/$_";
453: &logthis($dfname);
454: my $wcmd;
455: {
456: my $dfh=IO::File->new($dfname);
457: $cmd=<$dfh>;
458: }
459: chomp($cmd);
460: my $bcmd=$cmd;
461: if ($cmd =~ /^encrypt\:/) {
462: my $rcmd=$cmd;
463: $rcmd =~ s/^encrypt\://;
464: chomp($rcmd);
465: my $cmdlength=length($rcmd);
466: $rcmd.=" ";
467: my $encrequest='';
468: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
469: $encrequest.=
470: unpack("H16",$cipher->encrypt(substr($rcmd,$encidx,8)));
471: }
472: $cmd="enc:$cmdlength:$encrequest\n";
473: }
474: $SIG{ALRM}=sub { die "timeout" };
475: $SIG{__DIE__}='DEFAULT';
476: eval {
477: alarm(60);
478: print $remotesock "$cmd\n";
479: $answer=<$remotesock>;
480: chomp($answer);
481: alarm(0);
482: };
483: $SIG{ALRM}='DEFAULT';
484: $SIG{__DIE__}=\&catchexception;
485:
486: if (($answer ne '') && ($@!~/timeout/)) {
487: unlink("$dfname");
488: &logthis("Delayed $cmd to $conserver: >$answer<");
489: &logperm("S:$conserver:$bcmd");
490: }
491: } @allbuffered;
492:
493: # ------------------------------------------------------- Listen to UNIX socket
494: &status("Opening socket $conserver");
495: unless (
496: $server = IO::Socket::UNIX->new(Local => $port,
497: Type => SOCK_STREAM,
498: Listen => 10 )
499: ) {
500: my $st=120+int(rand(240));
501: &logthis(
502: "<font color=blue>WARNING: ".
503: "Can't make server socket $conserver ($st secs): $@</font>");
504: sleep($st);
505: exit;
506: };
507:
508: # -----------------------------------------------------------------------------
509:
510: &logthis("<font color=green>$conserver online</font>");
511:
512: # -----------------------------------------------------------------------------
513: # begin with empty buffers
514: %inbuffer = ();
515: %outbuffer = ();
516: %ready = ();
517:
518: tie %ready, 'Tie::RefHash';
519:
520: nonblock($server);
521: $select = IO::Select->new($server);
522:
523: # Main loop: check reads/accepts, check writes, check ready to process
524: while (1) {
525: my $client;
526: my $rv;
527: my $data;
528:
529: # check for new information on the connections we have
530:
531: # anything to read or accept?
532: foreach $client ($select->can_read(0.1)) {
533:
534: if ($client == $server) {
535: # accept a new connection
536: &status("Accept new connection: $conserver");
537: $client = $server->accept();
538: $select->add($client);
539: nonblock($client);
540: } else {
541: # read data
542: $data = '';
543: $rv = $client->recv($data, POSIX::BUFSIZ, 0);
544:
545: unless (defined($rv) && length $data) {
546: # This would be the end of file, so close the client
547: delete $inbuffer{$client};
548: delete $outbuffer{$client};
549: delete $ready{$client};
550:
551: &status("Idle $conserver");
552: $select->remove($client);
553: close $client;
554: next;
555: }
556:
557: $inbuffer{$client} .= $data;
558:
559: # test whether the data in the buffer or the data we
560: # just read means there is a complete request waiting
561: # to be fulfilled. If there is, set $ready{$client}
562: # to the requests waiting to be fulfilled.
563: while ($inbuffer{$client} =~ s/(.*\n)//) {
564: push( @{$ready{$client}}, $1 );
565: }
566: }
567: }
568:
569: # Any complete requests to process?
570: foreach $client (keys %ready) {
571: handle($client);
572: }
573:
574: # Buffers to flush?
575: foreach $client ($select->can_write(1)) {
576: # Skip this client if we have nothing to say
577: next unless exists $outbuffer{$client};
578:
579: $rv = $client->send($outbuffer{$client}, 0);
580: unless (defined $rv) {
581: # Whine, but move on.
582: &logthis("I was told I could write, but I can't.\n");
583: next;
584: }
585: $errno=$!;
586: if (($rv == length $outbuffer{$client}) ||
587: ($errno == POSIX::EWOULDBLOCK) || ($errno == 0)) {
588: substr($outbuffer{$client}, 0, $rv) = '';
589: delete $outbuffer{$client} unless length $outbuffer{$client};
590: } else {
591: # Couldn't write all the data, and it wasn't because
592: # it would have blocked. Shutdown and move on.
593:
594: &logthis("Dropping data with ".$errno.": ".
595: length($outbuffer{$client}).", $rv");
596:
597: delete $inbuffer{$client};
598: delete $outbuffer{$client};
599: delete $ready{$client};
600:
601: $select->remove($client);
602: close($client);
603: next;
604: }
605: }
606: }
607: }
608:
609: # ------------------------------------------------------- End of make_new_child
610:
611: # handle($socket) deals with all pending requests for $client
612: sub handle {
613: # requests are in $ready{$client}
614: # send output to $outbuffer{$client}
615: my $client = shift;
616: my $request;
617:
618: foreach $request (@{$ready{$client}}) {
619: # ============================================================= Process request
620: # $request is the text of the request
621: # put text of reply into $outbuffer{$client}
622: # -----------------------------------------------------------------------------
623: if ($request =~ /^encrypt\:/) {
624: my $cmd=$request;
625: $cmd =~ s/^encrypt\://;
626: chomp($cmd);
627: my $cmdlength=length($cmd);
628: $cmd.=" ";
629: my $encrequest='';
630: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
631: $encrequest.=
632: unpack("H16",$cipher->encrypt(substr($cmd,$encidx,8)));
633: }
634: $request="enc:$cmdlength:$encrequest\n";
635: }
636: # --------------------------------------------------------------- Main exchange
637: $SIG{ALRM}=sub { die "timeout" };
638: $SIG{__DIE__}='DEFAULT';
639: eval {
640: alarm(300);
641: &status("Sending $conserver: $request");
642: print $remotesock "$request";
643: &status("Waiting for reply from $conserver: $request");
644: $answer=<$remotesock>;
645: &status("Received reply: $request");
646: alarm(0);
647: };
648: if ($@=~/timeout/) {
649: $answer='';
650: &logthis(
651: "<font color=red>CRITICAL: Timeout $conserver: $request</font>");
652: }
653: $SIG{ALRM}='DEFAULT';
654: $SIG{__DIE__}=\&catchexception;
655:
656:
657: if ($answer) {
658: if ($answer =~ /^enc/) {
659: my ($cmd,$cmdlength,$encinput)=split(/:/,$answer);
660: chomp($encinput);
661: $answer='';
662: for (my $encidx=0;$encidx<length($encinput);$encidx+=16) {
663: $answer.=$cipher->decrypt(
664: pack("H16",substr($encinput,$encidx,16))
665: );
666: }
667: $answer=substr($answer,0,$cmdlength);
668: $answer.="\n";
669: }
670: $outbuffer{$client} .= $answer;
671: } else {
672: $outbuffer{$client} .= "con_lost\n";
673: }
674:
675: # ===================================================== Done processing request
676: }
677: delete $ready{$client};
678: &status("Completed $conserver: $request");
679: # -------------------------------------------------------------- End non-forker
680: }
681: # ---------------------------------------------------------- End make_new_child
682: }
683:
684: # nonblock($socket) puts socket into nonblocking mode
685: sub nonblock {
686: my $socket = shift;
687: my $flags;
688:
689:
690: $flags = fcntl($socket, F_GETFL, 0)
691: or die "Can't get flags for socket: $!\n";
692: fcntl($socket, F_SETFL, $flags | O_NONBLOCK)
693: or die "Can't make socket nonblocking: $!\n";
694: }
695:
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