1: #!/usr/bin/perl
2: # The LearningOnline Network with CAPA
3: # lonc maintains the connections to remote computers
4: #
5: # $Id: loncnew,v 1.27 2003/10/07 11:23:03 foxr Exp $
6: #
7: # Copyright Michigan State University Board of Trustees
8: #
9: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
10: ## LON-CAPA is free software; you can redistribute it and/or modify
11: # it under the terms of the GNU General Public License as published by
12: # the Free Software Foundation; either version 2 of the License, or
13: # (at your option) any later version.
14: #
15: # LON-CAPA is distributed in the hope that it will be useful,
16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18: # GNU General Public License for more details.
19: #
20: # You should have received a copy of the GNU General Public License
21: # along with LON-CAPA; if not, write to the Free Software
22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23: #
24: # /home/httpd/html/adm/gpl.txt
25: #
26: # http://www.lon-capa.org/
27: #
28: #
29: # new lonc handles n request out bver m connections to londs.
30: # This module is based on the Event class.
31: # Development iterations:
32: # - Setup basic event loop. (done)
33: # - Add timer dispatch. (done)
34: # - Add ability to accept lonc UNIX domain sockets. (done)
35: # - Add ability to create/negotiate lond connections (done).
36: # - Add general logic for dispatching requests and timeouts. (done).
37: # - Add support for the lonc/lond requests. (done).
38: # - Add logging/status monitoring.
39: # - Add Signal handling - HUP restarts. USR1 status report.
40: # - Add Configuration file I/O (done).
41: # - Add management/status request interface.
42: # - Add deferred request capability. (done)
43: # - Detect transmission timeouts.
44: #
45:
46: # Change log:
47: # $Log: loncnew,v $
48: # Revision 1.27 2003/10/07 11:23:03 foxr
49: # Installed and tested code to process reinit in parent server.
50: #
51: # Revision 1.26 2003/09/30 11:11:17 foxr
52: # Add book-keeping hashes to support the re-init procedure.
53: #
54: # Revision 1.25 2003/09/23 11:22:14 foxr
55: # Tested ability to receive sigusr2 This is now logged and must be
56: # properly implemented as a re-read of hosts and re-init of appropriate
57: # children.
58: #
59: # Revision 1.24 2003/09/16 09:46:42 foxr
60: # Added skeletal infrastructure to support SIGUSR2 update hosts request.
61: #
62: # Revision 1.23 2003/09/15 09:24:49 foxr
63: # Add use strict and fix all the fallout from that.
64: #
65: # Revision 1.22 2003/09/02 10:34:47 foxr
66: # - Fix errors in host dead detection logic (too many cases where the
67: # retries left were not getting incremented or just not checked).
68: # - Added some additional status to the ps axuww display:
69: # o Remaining retries on a host.
70: # o >>> DEAD <<< indicator if I've given up on a host.
71: # - Tested the SIGHUP will reset the retries remaining count (thanks to
72: # the above status stuff, and get allow the loncnew to re-try again
73: # on the host (thanks to the log).
74: #
75: # Revision 1.21 2003/08/26 09:19:51 foxr
76: # How embarrassing... put in the SocketTimeout function in loncnew and forgot
77: # to actually hook it into the LondTransaction. Added this to MakeLondConnection
78: # where it belongs... hopefully transactions (not just connection attempts) will
79: # timeout more speedily than the socket errors will catch it.
80: #
81: # Revision 1.20 2003/08/25 18:48:11 albertel
82: # - fixing a forgotten ;
83: #
84: # Revision 1.19 2003/08/19 09:31:46 foxr
85: # Get socket directory from configuration rather than the old hard coded test
86: # way that I forgot to un-hard code.
87: #
88: # Revision 1.18 2003/08/06 09:52:29 foxr
89: # Also needed to remember to fail in-flight transactions if their sends fail.
90: #
91: # Revision 1.17 2003/08/03 00:44:31 foxr
92: # 1. Correct handling of connection failure: Assume it means the host is
93: # unreachable and fail all of the queued transactions. Note that the
94: # inflight transactions should fail on their own time due either to timeout
95: # or send/receive failures.
96: # 2. Correct handling of logs for forced death signals. Pull the signal
97: # from the event watcher.
98: #
99: # Revision 1.16 2003/07/29 02:33:05 foxr
100: # Add SIGINT processing to child processes to toggle annoying trace mode
101: # on/off.. will try to use this to isolate the compute boud process issue.
102: #
103: # Revision 1.15 2003/07/15 02:07:05 foxr
104: # Added code for lonc/lond transaction timeouts. Who knows if it works right.
105: # The intent is for a timeout to fail any transaction in progress and kill
106: # off the sockt that timed out.
107: #
108: # Revision 1.14 2003/07/03 02:10:18 foxr
109: # Get all of the signals to work correctly.
110: #
111: # Revision 1.13 2003/07/02 01:31:55 foxr
112: # Added kill -HUP logic (restart).
113: #
114: # Revision 1.11 2003/06/25 01:54:44 foxr
115: # Fix more problems with transaction failure.
116: #
117: # Revision 1.10 2003/06/24 02:46:04 foxr
118: # Put a limit on the number of times we'll retry a connection.
119: # Start getting the signal stuff put in as well...note that need to get signals
120: # going or else the client will permanently give up on dead servers.
121: #
122: # Revision 1.9 2003/06/13 02:38:43 foxr
123: # Add logging in 'expected format'
124: #
125: # Revision 1.8 2003/06/11 02:04:35 foxr
126: # Support delayed transactions... this is done uniformly by encapsulating
127: # transactions in an object ... a LondTransaction that is implemented by
128: # LondTransaction.pm
129: #
130: # Revision 1.7 2003/06/03 01:59:39 foxr
131: # complete coding to support deferred transactions.
132: #
133: #
134: use strict;
135: use lib "/home/httpd/lib/perl/";
136: use lib "/home/foxr/newloncapa/types";
137: use Event qw(:DEFAULT );
138: use POSIX qw(:signal_h);
139: use POSIX;
140: use IO::Socket;
141: use IO::Socket::INET;
142: use IO::Socket::UNIX;
143: use IO::File;
144: use IO::Handle;
145: use Socket;
146: use Crypt::IDEA;
147: use LONCAPA::Queue;
148: use LONCAPA::Stack;
149: use LONCAPA::LondConnection;
150: use LONCAPA::LondTransaction;
151: use LONCAPA::Configuration;
152: use LONCAPA::HashIterator;
153:
154:
155: #
156: # Disable all signals we might receive from outside for now.
157: #
158:
159:
160: # Read the httpd configuration file to get perl variables
161: # normally set in apache modules:
162:
163: my $perlvarref = LONCAPA::Configuration::read_conf('loncapa.conf');
164: my %perlvar = %{$perlvarref};
165:
166: #
167: # parent and shared variables.
168:
169: my %ChildHash; # by pid -> host.
170: my %HostToPid; # By host -> pid.
171: my %HostHash; # by loncapaname -> IP.
172:
173:
174: my $MaxConnectionCount = 10; # Will get from config later.
175: my $ClientConnection = 0; # Uniquifier for client events.
176:
177: my $DebugLevel = 0;
178: my $NextDebugLevel= 10; # So Sigint can toggle this.
179: my $IdleTimeout= 3600; # Wait an hour before pruning connections.
180:
181: #
182: # The variables below are only used by the child processes.
183: #
184: my $RemoteHost; # Name of host child is talking to.
185: my $UnixSocketDir= $perlvar{'lonSockDir'};
186: my $IdleConnections = Stack->new(); # Set of idle connections
187: my %ActiveConnections; # Connections to the remote lond.
188: my %ActiveTransactions; # LondTransactions in flight.
189: my %ActiveClients; # Serial numbers of active clients by socket.
190: my $WorkQueue = Queue->new(); # Queue of pending transactions.
191: my $ConnectionCount = 0;
192: my $IdleSeconds = 0; # Number of seconds idle.
193: my $Status = ""; # Current status string.
194: my $RecentLogEntry = "";
195: my $ConnectionRetries=5; # Number of connection retries allowed.
196: my $ConnectionRetriesLeft=5; # Number of connection retries remaining.
197:
198: #
199: # The hash below gives the HTML format for log messages
200: # given a severity.
201: #
202: my %LogFormats;
203:
204: $LogFormats{"CRITICAL"} = "<font color=red>CRITICAL: %s</font>";
205: $LogFormats{"SUCCESS"} = "<font color=green>SUCCESS: %s</font>";
206: $LogFormats{"INFO"} = "<font color=yellow>INFO: %s</font>";
207: $LogFormats{"WARNING"} = "<font color=blue>WARNING: %s</font>";
208: $LogFormats{"DEFAULT"} = " %s ";
209:
210:
211:
212: =pod
213:
214: =head2 LogPerm
215:
216: Makes an entry into the permanent log file.
217:
218: =cut
219: sub LogPerm {
220: my $message=shift;
221: my $execdir=$perlvar{'lonDaemons'};
222: my $now=time;
223: my $local=localtime($now);
224: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
225: print $fh "$now:$message:$local\n";
226: }
227:
228: =pod
229:
230: =head2 Log
231:
232: Logs a message to the log file.
233: Parameters:
234:
235: =item severity
236:
237: One of CRITICAL, WARNING, INFO, SUCCESS used to select the
238: format string used to format the message. if the severity is
239: not a defined severity the Default format string is used.
240:
241: =item message
242:
243: The base message. In addtion to the format string, the message
244: will be appended to a string containing the name of our remote
245: host and the time will be formatted into the message.
246:
247: =cut
248:
249: sub Log {
250: my $severity = shift;
251: my $message = shift;
252:
253: if(!$LogFormats{$severity}) {
254: $severity = "DEFAULT";
255: }
256:
257: my $format = $LogFormats{$severity};
258:
259: # Put the window dressing in in front of the message format:
260:
261: my $now = time;
262: my $local = localtime($now);
263: my $finalformat = "$local ($$) [$RemoteHost] [$Status] ";
264: my $finalformat = $finalformat.$format."\n";
265:
266: # open the file and put the result.
267:
268: my $execdir = $perlvar{'lonDaemons'};
269: my $fh = IO::File->new(">>$execdir/logs/lonc.log");
270: my $msg = sprintf($finalformat, $message);
271: $RecentLogEntry = $msg;
272: print $fh $msg;
273:
274:
275: }
276:
277:
278: =pod
279:
280: =head2 GetPeerName
281:
282: Returns the name of the host that a socket object is connected to.
283:
284: =cut
285:
286: sub GetPeername {
287: my $connection = shift;
288: my $AdrFamily = shift;
289: my $peer = $connection->peername();
290: my $peerport;
291: my $peerip;
292: if($AdrFamily == AF_INET) {
293: ($peerport, $peerip) = sockaddr_in($peer);
294: my $peername = gethostbyaddr($peerip, $AdrFamily);
295: return $peername;
296: } elsif ($AdrFamily == AF_UNIX) {
297: my $peerfile;
298: ($peerfile) = sockaddr_un($peer);
299: return $peerfile;
300: }
301: }
302: #----------------------------- Timer management ------------------------
303: =pod
304:
305: =head2 Debug
306:
307: Invoked to issue a debug message.
308:
309: =cut
310:
311: sub Debug {
312: my $level = shift;
313: my $message = shift;
314: if ($level <= $DebugLevel) {
315: Log("INFO", "-Debug- $message host = $RemoteHost");
316: }
317: }
318:
319: sub SocketDump {
320: my $level = shift;
321: my $socket= shift;
322: if($level <= $DebugLevel) {
323: $socket->Dump();
324: }
325: }
326:
327: =pod
328:
329: =head2 ShowStatus
330:
331: Place some text as our pid status.
332: and as what we return in a SIGUSR1
333:
334: =cut
335: sub ShowStatus {
336: my $state = shift;
337: my $now = time;
338: my $local = localtime($now);
339: $Status = $local.": ".$state;
340: $0='lonc: '.$state.' '.$local;
341: }
342:
343: =pod
344:
345: =head 2 SocketTimeout
346:
347: Called when an action on the socket times out. The socket is
348: destroyed and any active transaction is failed.
349:
350:
351: =cut
352: sub SocketTimeout {
353: my $Socket = shift;
354:
355: KillSocket($Socket); # A transaction timeout also counts as
356: # a connection failure:
357: $ConnectionRetriesLeft--;
358: }
359:
360: =pod
361:
362: =head2 Tick
363:
364: Invoked each timer tick.
365:
366: =cut
367:
368:
369: sub Tick {
370: my $client;
371: if($ConnectionRetriesLeft > 0) {
372: ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
373: ." Retries remaining: ".$ConnectionRetriesLeft);
374: } else {
375: ShowStatus(GetServerHost()." >> DEAD <<");
376: }
377: # Is it time to prune connection count:
378:
379:
380: if($IdleConnections->Count() &&
381: ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
382: $IdleSeconds++;
383: if($IdleSeconds > $IdleTimeout) { # Prune a connection...
384: my $Socket = $IdleConnections->pop();
385: KillSocket($Socket);
386: }
387: } else {
388: $IdleSeconds = 0; # Reset idle count if not idle.
389: }
390: #
391: # For each inflight transaction, tick down its timeout counter.
392: #
393: foreach my $item (keys %ActiveTransactions) {
394: my $Socket = $ActiveTransactions{$item}->getServer();
395: $Socket->Tick();
396: }
397: # Do we have work in the queue, but no connections to service them?
398: # If so, try to make some new connections to get things going again.
399: #
400:
401: my $Requests = $WorkQueue->Count();
402: if (($ConnectionCount == 0) && ($Requests > 0)) {
403: if ($ConnectionRetriesLeft > 0) {
404: my $Connections = ($Requests <= $MaxConnectionCount) ?
405: $Requests : $MaxConnectionCount;
406: Debug(1,"Work but no connections, start ".$Connections." of them");
407: my $successCount = 0;
408: for (my $i =0; $i < $Connections; $i++) {
409: $successCount += MakeLondConnection();
410: }
411: if($successCount == 0) { # All connections failed:
412: Debug(1,"Work in queue failed to make any connectiouns\n");
413: EmptyQueue(); # Fail pending transactions with con_lost.
414: }
415: } else {
416: ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
417: Debug(1,"Work in queue, but gave up on connections..flushing\n");
418: EmptyQueue(); # Connections can't be established.
419: }
420:
421: }
422: }
423:
424: =pod
425:
426: =head2 SetupTimer
427:
428: Sets up a 1 per sec recurring timer event. The event handler is used to:
429:
430: =item
431:
432: Trigger timeouts on communications along active sockets.
433:
434: =item
435:
436: Trigger disconnections of idle sockets.
437:
438: =cut
439:
440: sub SetupTimer {
441: Debug(6, "SetupTimer");
442: Event->timer(interval => 1, debug => 1, cb => \&Tick );
443: }
444:
445: =pod
446:
447: =head2 ServerToIdle
448:
449: This function is called when a connection to the server is
450: ready for more work.
451:
452: If there is work in the Work queue the top element is dequeued
453: and the connection will start to work on it. If the work queue is
454: empty, the connection is pushed on the idle connection stack where
455: it will either get another work unit, or alternatively, if it sits there
456: long enough, it will be shut down and released.
457:
458: =cut
459:
460: sub ServerToIdle {
461: my $Socket = shift; # Get the socket.
462: delete($ActiveTransactions{$Socket}); # Server has no transaction
463:
464: &Debug(6, "Server to idle");
465:
466: # If there's work to do, start the transaction:
467:
468: my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
469: unless($reqdata eq undef) {
470: Debug(9, "Queue gave request data: ".$reqdata->getRequest());
471: &StartRequest($Socket, $reqdata);
472:
473: } else {
474:
475: # There's no work waiting, so push the server to idle list.
476: &Debug(8, "No new work requests, server connection going idle");
477: $IdleConnections->push($Socket);
478: }
479: }
480:
481: =pod
482:
483: =head2 ClientWritable
484:
485: Event callback for when a client socket is writable.
486:
487: This callback is established when a transaction reponse is
488: avaiable from lond. The response is forwarded to the unix socket
489: as it becomes writable in this sub.
490:
491: Parameters:
492:
493: =item Event
494:
495: The event that has been triggered. Event->w->data is
496: the data and Event->w->fd is the socket to write.
497:
498: =cut
499:
500: sub ClientWritable {
501: my $Event = shift;
502: my $Watcher = $Event->w;
503: my $Data = $Watcher->data;
504: my $Socket = $Watcher->fd;
505:
506: # Try to send the data:
507:
508: &Debug(6, "ClientWritable writing".$Data);
509: &Debug(9, "Socket is: ".$Socket);
510:
511: if($Socket->connected) {
512: my $result = $Socket->send($Data, 0);
513:
514: # $result undefined: the write failed.
515: # otherwise $result is the number of bytes written.
516: # Remove that preceding string from the data.
517: # If the resulting data is empty, destroy the watcher
518: # and set up a read event handler to accept the next
519: # request.
520:
521: &Debug(9,"Send result is ".$result." Defined: ".defined($result));
522: if(defined($result)) {
523: &Debug(9, "send result was defined");
524: if($result == length($Data)) { # Entire string sent.
525: &Debug(9, "ClientWritable data all written");
526: $Watcher->cancel();
527: #
528: # Set up to read next request from socket:
529:
530: my $descr = sprintf("Connection to lonc client %d",
531: $ActiveClients{$Socket});
532: Event->io(cb => \&ClientRequest,
533: poll => 'r',
534: desc => $descr,
535: data => "",
536: fd => $Socket);
537:
538: } else { # Partial string sent.
539: $Watcher->data(substr($Data, $result));
540: if($result == 0) { # client hung up on us!!
541: Log("INFO", "lonc pipe client hung up on us!");
542: $Watcher->cancel;
543: $Socket->shutdown(2);
544: $Socket->close();
545: }
546: }
547:
548: } else { # Error of some sort...
549:
550: # Some errnos are possible:
551: my $errno = $!;
552: if($errno == POSIX::EWOULDBLOCK ||
553: $errno == POSIX::EAGAIN ||
554: $errno == POSIX::EINTR) {
555: # No action taken?
556: } else { # Unanticipated errno.
557: &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
558: $Watcher->cancel; # Stop the watcher.
559: $Socket->shutdown(2); # Kill connection
560: $Socket->close(); # Close the socket.
561: }
562:
563: }
564: } else {
565: $Watcher->cancel(); # A delayed request...just cancel.
566: }
567: }
568:
569: =pod
570:
571: =head2 CompleteTransaction
572:
573: Called when the reply data has been received for a lond
574: transaction. The reply data must now be sent to the
575: ultimate client on the other end of the Unix socket. This is
576: done by setting up a writable event for the socket with the
577: data the reply data.
578:
579: Parameters:
580:
581: =item Socket
582:
583: Socket on which the lond transaction occured. This is a
584: LondConnection. The data received is in the TransactionReply member.
585:
586: =item Transaction
587:
588: The transaction that is being completed.
589:
590: =cut
591:
592: sub CompleteTransaction {
593: &Debug(6,"Complete transaction");
594: my $Socket = shift;
595: my $Transaction = shift;
596:
597: if (!$Transaction->isDeferred()) { # Normal transaction
598: my $data = $Socket->GetReply(); # Data to send.
599: StartClientReply($Transaction, $data);
600: } else { # Delete deferred transaction file.
601: Log("SUCCESS", "A delayed transaction was completed");
602: LogPerm("S:$Transaction->getClient() :".$Transaction->getRequest());
603: unlink $Transaction->getFile();
604: }
605: }
606: =pod
607: =head1 StartClientReply
608:
609: Initiates a reply to a client where the reply data is a parameter.
610:
611: =head2 parameters:
612:
613: =item Transaction
614:
615: The transaction for which we are responding to the client.
616:
617: =item data
618:
619: The data to send to apached client.
620:
621: =cut
622: sub StartClientReply {
623: my $Transaction = shift;
624: my $data = shift;
625:
626:
627: my $Client = $Transaction->getClient();
628:
629: &Debug(8," Reply was: ".$data);
630: my $Serial = $ActiveClients{$Client};
631: my $desc = sprintf("Connection to lonc client %d",
632:
633: $Serial);
634: Event->io(fd => $Client,
635: poll => "w",
636: desc => $desc,
637: cb => \&ClientWritable,
638: data => $data);
639: }
640: =pod
641: =head2 FailTransaction
642:
643: Finishes a transaction with failure because the associated lond socket
644: disconnected. There are two possibilities:
645: - The transaction is deferred: in which case we just quietly
646: delete the transaction since there is no client connection.
647: - The transaction is 'live' in which case we initiate the sending
648: of "con_lost" to the client.
649:
650: Deleting the transaction means killing it from the
651: %ActiveTransactions hash.
652:
653: Parameters:
654:
655: =item client
656:
657: The LondTransaction we are failing.
658:
659: =cut
660:
661: sub FailTransaction {
662: my $transaction = shift;
663: Log("WARNING", "Failing transaction ".$transaction->getRequest());
664: Debug(1, "Failing transaction: ".$transaction->getRequest());
665: if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
666: my $client = $transaction->getClient();
667: Debug(1," Replying con_lost to ".$transaction->getRequest());
668: StartClientReply($transaction, "con_lost\n");
669: }
670: if($ConnectionRetriesLeft <= 0) {
671: Log("CRITICAL", "Host marked dead: ".GetServerHost());
672: }
673:
674: }
675:
676: =pod
677: =head1 EmptyQueue
678:
679: Fails all items in the work queue with con_lost.
680: Note that each item in the work queue is a transaction.
681:
682: =cut
683: sub EmptyQueue {
684: $ConnectionRetriesLeft--; # Counts as connection failure too.
685: while($WorkQueue->Count()) {
686: my $request = $WorkQueue->dequeue(); # This is a transaction
687: FailTransaction($request);
688: }
689: }
690:
691: =pod
692:
693: =head2 CloseAllLondConnections
694:
695: Close all connections open on lond prior to exit e.g.
696:
697: =cut
698: sub CloseAllLondConnections {
699: foreach my $Socket (keys %ActiveConnections) {
700: KillSocket($Socket);
701: }
702: }
703: =cut
704:
705: =pod
706:
707: =head2 KillSocket
708:
709: Destroys a socket. This function can be called either when a socket
710: has died of 'natural' causes or because a socket needs to be pruned due to
711: idleness. If the socket has died naturally, if there are no longer any
712: live connections a new connection is created (in case there are transactions
713: in the queue). If the socket has been pruned, it is never re-created.
714:
715: Parameters:
716:
717: =item Socket
718:
719: The socket to kill off.
720:
721: =item Restart
722:
723: nonzero if we are allowed to create a new connection.
724:
725:
726: =cut
727: sub KillSocket {
728: my $Socket = shift;
729:
730: Log("WARNING", "Shutting down a socket");
731: $Socket->Shutdown();
732:
733: # If the socket came from the active connection set,
734: # delete its transaction... note that FailTransaction should
735: # already have been called!!!
736: # otherwise it came from the idle set.
737: #
738:
739: if(exists($ActiveTransactions{$Socket})) {
740: delete ($ActiveTransactions{$Socket});
741: }
742: if(exists($ActiveConnections{$Socket})) {
743: delete($ActiveConnections{$Socket});
744: }
745: $ConnectionCount--;
746:
747: # If the connection count has gone to zero and there is work in the
748: # work queue, the work all gets failed with con_lost.
749: #
750: if($ConnectionCount == 0) {
751: EmptyQueue();
752: }
753: }
754:
755: =pod
756:
757: =head2 LondReadable
758:
759: This function is called whenever a lond connection
760: is readable. The action is state dependent:
761:
762: =head3 State=Initialized
763:
764: We''re waiting for the challenge, this is a no-op until the
765: state changes.
766:
767: =head3 State=Challenged
768:
769: The challenge has arrived we need to transition to Writable.
770: The connection must echo the challenge back.
771:
772: =head3 State=ChallengeReplied
773:
774: The challenge has been replied to. The we are receiveing the
775: 'ok' from the partner.
776:
777: =head3 State=RequestingKey
778:
779: The ok has been received and we need to send the request for
780: an encryption key. Transition to writable for that.
781:
782: =head3 State=ReceivingKey
783:
784: The the key has been requested, now we are reading the new key.
785:
786: =head3 State=Idle
787:
788: The encryption key has been negotiated or we have finished
789: reading data from the a transaction. If the callback data has
790: a client as well as the socket iformation, then we are
791: doing a transaction and the data received is relayed to the client
792: before the socket is put on the idle list.
793:
794: =head3 State=SendingRequest
795:
796: I do not think this state can be received here, but if it is,
797: the appropriate thing to do is to transition to writable, and send
798: the request.
799:
800: =head3 State=ReceivingReply
801:
802: We finished sending the request to the server and now transition
803: to readable to receive the reply.
804:
805: The parameter to this function are:
806:
807: The event. Implicit in this is the watcher and its data. The data
808: contains at least the lond connection object and, if a
809: transaction is in progress, the socket attached to the local client.
810:
811: =cut
812:
813: sub LondReadable {
814:
815: my $Event = shift;
816: my $Watcher = $Event->w;
817: my $Socket = $Watcher->data;
818: my $client = undef;
819:
820: &Debug(6,"LondReadable called state = ".$Socket->GetState());
821:
822:
823: my $State = $Socket->GetState(); # All action depends on the state.
824:
825: SocketDump(6, $Socket);
826: my $status = $Socket->Readable();
827:
828: &Debug(2, "Socket->Readable returned: $status");
829:
830: if($status != 0) {
831: # bad return from socket read. Currently this means that
832: # The socket has become disconnected. We fail the transaction.
833:
834: Log("WARNING",
835: "Lond connection lost.");
836: if(exists($ActiveTransactions{$Socket})) {
837: FailTransaction($ActiveTransactions{$Socket});
838: }
839: $Watcher->cancel();
840: KillSocket($Socket);
841: $ConnectionRetriesLeft--; # Counts as connection failure
842: return;
843: }
844: SocketDump(6,$Socket);
845:
846: $State = $Socket->GetState(); # Update in case of transition.
847: &Debug(6, "After read, state is ".$State);
848:
849: if($State eq "Initialized") {
850:
851:
852: } elsif ($State eq "ChallengeReceived") {
853: # The challenge must be echoed back; The state machine
854: # in the connection takes care of setting that up. Just
855: # need to transition to writable:
856:
857: $Watcher->cb(\&LondWritable);
858: $Watcher->poll("w");
859:
860: } elsif ($State eq "ChallengeReplied") {
861:
862:
863: } elsif ($State eq "RequestingKey") {
864: # The ok was received. Now we need to request the key
865: # That requires us to be writable:
866:
867: $Watcher->cb(\&LondWritable);
868: $Watcher->poll("w");
869:
870: } elsif ($State eq "ReceivingKey") {
871:
872: } elsif ($State eq "Idle") {
873: # If necessary, complete a transaction and then go into the
874: # idle queue.
875: # Note that a trasition to idle indicates a live lond
876: # on the other end so reset the connection retries.
877: #
878: $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
879: $Watcher->cancel();
880: if(exists($ActiveTransactions{$Socket})) {
881: Debug(8,"Completing transaction!!");
882: CompleteTransaction($Socket,
883: $ActiveTransactions{$Socket});
884: } else {
885: Log("SUCCESS", "Connection ".$ConnectionCount." to "
886: .$RemoteHost." now ready for action");
887: }
888: ServerToIdle($Socket); # Next work unit or idle.
889:
890: } elsif ($State eq "SendingRequest") {
891: # We need to be writable for this and probably don't belong
892: # here inthe first place.
893:
894: Deubg(6, "SendingRequest state encountered in readable");
895: $Watcher->poll("w");
896: $Watcher->cb(\&LondWritable);
897:
898: } elsif ($State eq "ReceivingReply") {
899:
900:
901: } else {
902: # Invalid state.
903: Debug(4, "Invalid state in LondReadable");
904: }
905: }
906:
907: =pod
908:
909: =head2 LondWritable
910:
911: This function is called whenever a lond connection
912: becomes writable while there is a writeable monitoring
913: event. The action taken is very state dependent:
914:
915: =head3 State = Connected
916:
917: The connection is in the process of sending the 'init' hailing to the
918: lond on the remote end. The connection object''s Writable member is
919: called. On error, ConnectionError is called to destroy the connection
920: and remove it from the ActiveConnections hash
921:
922: =head3 Initialized
923:
924: 'init' has been sent, writability monitoring is removed and
925: readability monitoring is started with LondReadable as the callback.
926:
927: =head3 ChallengeReceived
928:
929: The connection has received the who are you challenge from the remote
930: system, and is in the process of sending the challenge
931: response. Writable is called.
932:
933: =head3 ChallengeReplied
934:
935: The connection has replied to the initial challenge The we switch to
936: monitoring readability looking for the server to reply with 'ok'.
937:
938: =head3 RequestingKey
939:
940: The connection is in the process of requesting its encryption key.
941: Writable is called.
942:
943: =head3 ReceivingKey
944:
945: The connection has sent the request for a key. Switch to readability
946: monitoring to accept the key
947:
948: =head3 SendingRequest
949:
950: The connection is in the process of sending a request to the server.
951: This request is part of a client transaction. All the states until
952: now represent the client setup protocol. Writable is called.
953:
954: =head3 ReceivingReply
955:
956: The connection has sent a request. Now it must receive a reply.
957: Readability monitoring is requested.
958:
959: This function is an event handler and therefore receives as
960: a parameter the event that has fired. The data for the watcher
961: of this event is a reference to a list of one or two elements,
962: depending on state. The first (and possibly only) element is the
963: socket. The second (present only if a request is in progress)
964: is the socket on which to return a reply to the caller.
965:
966: =cut
967:
968: sub LondWritable {
969: my $Event = shift;
970: my $Watcher = $Event->w;
971: my $Socket = $Watcher->data;
972: my $State = $Socket->GetState();
973:
974: Debug(6,"LondWritable State = ".$State."\n");
975:
976:
977: # Figure out what to do depending on the state of the socket:
978:
979:
980:
981:
982: SocketDump(6,$Socket);
983:
984: if ($State eq "Connected") {
985:
986: if ($Socket->Writable() != 0) {
987: # The write resulted in an error.
988: # We'll treat this as if the socket got disconnected:
989: Log("WARNING", "Connection to ".$RemoteHost.
990: " has been disconnected");
991: FailTransaction($ActiveTransactions{$Socket});
992: $Watcher->cancel();
993: KillSocket($Socket);
994: return;
995: }
996: # "init" is being sent...
997:
998:
999: } elsif ($State eq "Initialized") {
1000:
1001: # Now that init was sent, we switch
1002: # to watching for readability:
1003:
1004: $Watcher->cb(\&LondReadable);
1005: $Watcher->poll("r");
1006:
1007: } elsif ($State eq "ChallengeReceived") {
1008: # We received the challenge, now we
1009: # are echoing it back. This is a no-op,
1010: # we're waiting for the state to change
1011:
1012: if($Socket->Writable() != 0) {
1013:
1014: $Watcher->cancel();
1015: KillSocket($Socket);
1016: return;
1017: }
1018:
1019: } elsif ($State eq "ChallengeReplied") {
1020: # The echo was sent back, so we switch
1021: # to watching readability.
1022:
1023: $Watcher->cb(\&LondReadable);
1024: $Watcher->poll("r");
1025:
1026: } elsif ($State eq "RequestingKey") {
1027: # At this time we're requesting the key.
1028: # again, this is essentially a no-op.
1029: # we'll write the next chunk until the
1030: # state changes.
1031:
1032: if($Socket->Writable() != 0) {
1033: # Write resulted in an error.
1034:
1035: $Watcher->cancel();
1036: KillSocket($Socket);
1037: return;
1038:
1039: }
1040: } elsif ($State eq "ReceivingKey") {
1041: # Now we need to wait for the key
1042: # to come back from the peer:
1043:
1044: $Watcher->cb(\&LondReadable);
1045: $Watcher->poll("r");
1046:
1047: } elsif ($State eq "SendingRequest") {
1048: # At this time we are sending a request to the
1049: # peer... write the next chunk:
1050:
1051: if($Socket->Writable() != 0) {
1052:
1053: if(exists($ActiveTransactions{$Socket})) {
1054: Debug(3, "Lond connection lost, failing transactions");
1055: FailTransaction($ActiveTransactions{$Socket});
1056: }
1057: $Watcher->cancel();
1058: KillSocket($Socket);
1059: return;
1060:
1061: }
1062:
1063: } elsif ($State eq "ReceivingReply") {
1064: # The send has completed. Wait for the
1065: # data to come in for a reply.
1066: Debug(8,"Writable sent request/receiving reply");
1067: $Watcher->cb(\&LondReadable);
1068: $Watcher->poll("r");
1069:
1070: } else {
1071: # Control only passes here on an error:
1072: # the socket state does not match any
1073: # of the known states... so an error
1074: # must be logged.
1075:
1076: &Debug(4, "Invalid socket state ".$State."\n");
1077: }
1078:
1079: }
1080: =pod
1081:
1082: =cut
1083: sub QueueDelayed {
1084: Debug(3,"QueueDelayed called");
1085:
1086: my $path = "$perlvar{'lonSockDir'}/delayed";
1087:
1088: Debug(4, "Delayed path: ".$path);
1089: opendir(DIRHANDLE, $path);
1090:
1091: my @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
1092: closedir(DIRHANDLE);
1093: my $dfname;
1094: my $reqfile;
1095: foreach $dfname (sort @alldelayed) {
1096: $reqfile = "$path/$dfname";
1097: Debug(4, "queueing ".$reqfile);
1098: my $Handle = IO::File->new($reqfile);
1099: my $cmd = <$Handle>;
1100: chomp $cmd; # There may or may not be a newline...
1101: $cmd = $cmd."\n"; # now for sure there's exactly one newline.
1102: my $Transaction = LondTransaction->new($cmd);
1103: $Transaction->SetDeferred($reqfile);
1104: QueueTransaction($Transaction);
1105: }
1106:
1107: }
1108:
1109: =pod
1110:
1111: =head2 MakeLondConnection
1112:
1113: Create a new lond connection object, and start it towards its initial
1114: idleness. Once idle, it becomes elligible to receive transactions
1115: from the work queue. If the work queue is not empty when the
1116: connection is completed and becomes idle, it will dequeue an entry and
1117: start off on it.
1118:
1119: =cut
1120:
1121: sub MakeLondConnection {
1122: Debug(4,"MakeLondConnection to ".GetServerHost()." on port "
1123: .GetServerPort());
1124:
1125: my $Connection = LondConnection->new(&GetServerHost(),
1126: &GetServerPort());
1127:
1128: if($Connection == undef) { # Needs to be more robust later.
1129: Log("CRITICAL","Failed to make a connection with lond.");
1130: $ConnectionRetriesLeft--;
1131: return 0; # Failure.
1132: } else {
1133:
1134: # The connection needs to have writability
1135: # monitored in order to send the init sequence
1136: # that starts the whole authentication/key
1137: # exchange underway.
1138: #
1139: my $Socket = $Connection->GetSocket();
1140: if($Socket == undef) {
1141: die "did not get a socket from the connection";
1142: } else {
1143: &Debug(9,"MakeLondConnection got socket: ".$Socket);
1144: }
1145:
1146: $Connection->SetTimeoutCallback(\&SocketTimeout);
1147:
1148: my $event = Event->io(fd => $Socket,
1149: poll => 'w',
1150: cb => \&LondWritable,
1151: data => $Connection,
1152: desc => 'Connection to lond server');
1153: $ActiveConnections{$Connection} = $event;
1154:
1155: $ConnectionCount++;
1156: Debug(4, "Connection count = ".$ConnectionCount);
1157: if($ConnectionCount == 1) { # First Connection:
1158: QueueDelayed;
1159: }
1160: Log("SUCESS", "Created connection ".$ConnectionCount
1161: ." to host ".GetServerHost());
1162: return 1; # Return success.
1163: }
1164:
1165: }
1166:
1167: =pod
1168:
1169: =head2 StartRequest
1170:
1171: Starts a lond request going on a specified lond connection.
1172: parameters are:
1173:
1174: =item $Lond
1175:
1176: Connection to the lond that will send the transaction and receive the
1177: reply.
1178:
1179: =item $Client
1180:
1181: Connection to the client that is making this request We got the
1182: request from this socket, and when the request has been relayed to
1183: lond and we get a reply back from lond it will get sent to this
1184: socket.
1185:
1186: =item $Request
1187:
1188: The text of the request to send.
1189:
1190: =cut
1191:
1192: sub StartRequest {
1193: my $Lond = shift;
1194: my $Request = shift; # This is a LondTransaction.
1195:
1196: Debug(6, "StartRequest: ".$Request->getRequest());
1197:
1198: my $Socket = $Lond->GetSocket();
1199:
1200: $Request->Activate($Lond);
1201: $ActiveTransactions{$Lond} = $Request;
1202:
1203: $Lond->InitiateTransaction($Request->getRequest());
1204: my $event = Event->io(fd => $Socket,
1205: poll => "w",
1206: cb => \&LondWritable,
1207: data => $Lond,
1208: desc => "lond transaction connection");
1209: $ActiveConnections{$Lond} = $event;
1210: Debug(8," Start Request made watcher data with ".$event->data."\n");
1211: }
1212:
1213: =pod
1214:
1215: =head2 QueueTransaction
1216:
1217: If there is an idle lond connection, it is put to work doing this
1218: transaction. Otherwise, the transaction is placed in the work queue.
1219: If placed in the work queue and the maximum number of connections has
1220: not yet been created, a new connection will be started. Our goal is
1221: to eventually have a sufficient number of connections that the work
1222: queue will typically be empty. parameters are:
1223:
1224: =item Socket
1225:
1226: open on the lonc client.
1227:
1228: =item Request
1229:
1230: data to send to the lond.
1231:
1232: =cut
1233:
1234: sub QueueTransaction {
1235:
1236: my $requestData = shift; # This is a LondTransaction.
1237: my $cmd = $requestData->getRequest();
1238:
1239: Debug(6,"QueueTransaction: ".$cmd);
1240:
1241: my $LondSocket = $IdleConnections->pop();
1242: if(!defined $LondSocket) { # Need to queue request.
1243: Debug(8,"Must queue...");
1244: $WorkQueue->enqueue($requestData);
1245: if($ConnectionCount < $MaxConnectionCount) {
1246: if($ConnectionRetriesLeft > 0) {
1247: Debug(4,"Starting additional lond connection");
1248: if(MakeLondConnection() == 0) {
1249: EmptyQueue(); # Fail transactions, can't make connection.
1250: }
1251: } else {
1252: ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
1253: EmptyQueue(); # It's worse than that ... he's dead Jim.
1254: }
1255: }
1256: } else { # Can start the request:
1257: Debug(8,"Can start...");
1258: StartRequest($LondSocket, $requestData);
1259: }
1260: }
1261:
1262: #-------------------------- Lonc UNIX socket handling ---------------------
1263:
1264: =pod
1265:
1266: =head2 ClientRequest
1267: Callback that is called when data can be read from the UNIX domain
1268: socket connecting us with an apache server process.
1269:
1270: =cut
1271:
1272: sub ClientRequest {
1273: Debug(6, "ClientRequest");
1274: my $event = shift;
1275: my $watcher = $event->w;
1276: my $socket = $watcher->fd;
1277: my $data = $watcher->data;
1278: my $thisread;
1279:
1280: Debug(9, " Watcher named: ".$watcher->desc);
1281:
1282: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1283: Debug(8, "rcv: data length = ".length($thisread)
1284: ." read =".$thisread);
1285: unless (defined $rv && length($thisread)) {
1286: # Likely eof on socket.
1287: Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
1288: close($socket);
1289: $watcher->cancel();
1290: delete($ActiveClients{$socket});
1291: return;
1292: }
1293: Debug(8,"Data: ".$data." this read: ".$thisread);
1294: $data = $data.$thisread; # Append new data.
1295: $watcher->data($data);
1296: if($data =~ /(.*\n)/) { # Request entirely read.
1297: if($data eq "close_connection_exit\n") {
1298: Log("CRITICAL",
1299: "Request Close Connection ... exiting");
1300: CloseAllLondConnections();
1301: exit;
1302: }
1303: Debug(8, "Complete transaction received: ".$data);
1304: my $Transaction = LondTransaction->new($data);
1305: $Transaction->SetClient($socket);
1306: QueueTransaction($Transaction);
1307: $watcher->cancel(); # Done looking for input data.
1308: }
1309:
1310: }
1311:
1312:
1313: =pod
1314:
1315: =head2 NewClient
1316:
1317: Callback that is called when a connection is received on the unix
1318: socket for a new client of lonc. The callback is parameterized by the
1319: event.. which is a-priori assumed to be an io event, and therefore has
1320: an fd member that is the Listener socket. We Accept the connection
1321: and register a new event on the readability of that socket:
1322:
1323: =cut
1324:
1325: sub NewClient {
1326: Debug(6, "NewClient");
1327: my $event = shift; # Get the event parameters.
1328: my $watcher = $event->w;
1329: my $socket = $watcher->fd; # Get the event' socket.
1330: my $connection = $socket->accept(); # Accept the client connection.
1331: Debug(8,"Connection request accepted from "
1332: .GetPeername($connection, AF_UNIX));
1333:
1334:
1335: my $description = sprintf("Connection to lonc client %d",
1336: $ClientConnection);
1337: Debug(9, "Creating event named: ".$description);
1338: Event->io(cb => \&ClientRequest,
1339: poll => 'r',
1340: desc => $description,
1341: data => "",
1342: fd => $connection);
1343: $ActiveClients{$connection} = $ClientConnection;
1344: $ClientConnection++;
1345: }
1346:
1347: =pod
1348:
1349: =head2 GetLoncSocketPath
1350:
1351: Returns the name of the UNIX socket on which to listen for client
1352: connections.
1353:
1354: =cut
1355:
1356: sub GetLoncSocketPath {
1357: return $UnixSocketDir."/".GetServerHost();
1358: }
1359:
1360: =pod
1361:
1362: =head2 GetServerHost
1363:
1364: Returns the host whose lond we talk with.
1365:
1366: =cut
1367:
1368: sub GetServerHost {
1369: return $RemoteHost; # Setup by the fork.
1370: }
1371:
1372: =pod
1373:
1374: =head2 GetServerPort
1375:
1376: Returns the lond port number.
1377:
1378: =cut
1379:
1380: sub GetServerPort {
1381: return $perlvar{londPort};
1382: }
1383:
1384: =pod
1385:
1386: =head2 SetupLoncListener
1387:
1388: Setup a lonc listener event. The event is called when the socket
1389: becomes readable.. that corresponds to the receipt of a new
1390: connection. The event handler established will accept the connection
1391: (creating a communcations channel), that int turn will establish
1392: another event handler to subess requests.
1393:
1394: =cut
1395:
1396: sub SetupLoncListener {
1397:
1398: my $socket;
1399: my $SocketName = GetLoncSocketPath();
1400: unlink($SocketName);
1401: unless ($socket =IO::Socket::UNIX->new(Local => $SocketName,
1402: Listen => 10,
1403: Type => SOCK_STREAM)) {
1404: die "Failed to create a lonc listner socket";
1405: }
1406: Event->io(cb => \&NewClient,
1407: poll => 'r',
1408: desc => 'Lonc listener Unix Socket',
1409: fd => $socket);
1410: }
1411:
1412: =pod
1413:
1414: =head2 ChildStatus
1415:
1416: Child USR1 signal handler to report the most recent status
1417: into the status file.
1418:
1419: We also use this to reset the retries count in order to allow the
1420: client to retry connections with a previously dead server.
1421: =cut
1422: sub ChildStatus {
1423: my $event = shift;
1424: my $watcher = $event->w;
1425:
1426: Debug(2, "Reporting child status because : ".$watcher->data);
1427: my $docdir = $perlvar{'lonDocRoot'};
1428: my $fh = IO::File->new(">>$docdir/lon-status/loncstatus.txt");
1429: print $fh $$."\t".$RemoteHost."\t".$Status."\t".
1430: $RecentLogEntry."\n";
1431: $ConnectionRetriesLeft = $ConnectionRetries;
1432: }
1433:
1434: =pod
1435:
1436: =head2 SignalledToDeath
1437:
1438: Called in response to a signal that causes a chid process to die.
1439:
1440: =cut
1441:
1442:
1443: sub SignalledToDeath {
1444: my $event = shift;
1445: my $watcher= $event->w;
1446:
1447: Debug(2,"Signalled to death! via ".$watcher->data);
1448: my ($signal) = $watcher->data;
1449: chomp($signal);
1450: Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "
1451: ."died through "."\"$signal\"");
1452: LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
1453: ."\"$signal\"");
1454: exit 0;
1455:
1456: }
1457:
1458: =head2 ToggleDebug
1459:
1460: This sub toggles trace debugging on and off.
1461:
1462: =cut
1463:
1464: sub ToggleDebug {
1465: my $Current = $DebugLevel;
1466: $DebugLevel = $NextDebugLevel;
1467: $NextDebugLevel = $Current;
1468:
1469: Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
1470:
1471: }
1472:
1473: =head2 ChildProcess
1474:
1475: This sub implements a child process for a single lonc daemon.
1476:
1477: =cut
1478:
1479: sub ChildProcess {
1480:
1481:
1482: #
1483: # Signals must be handled by the Event framework...
1484: #
1485:
1486: Event->signal(signal => "QUIT",
1487: cb => \&SignalledToDeath,
1488: data => "QUIT");
1489: Event->signal(signal => "HUP",
1490: cb => \&ChildStatus,
1491: data => "HUP");
1492: Event->signal(signal => "USR1",
1493: cb => \&ChildStatus,
1494: data => "USR1");
1495: Event->signal(signal => "INT",
1496: cb => \&ToggleDebug,
1497: data => "INT");
1498:
1499: SetupTimer();
1500:
1501: SetupLoncListener();
1502:
1503: $Event::Debuglevel = $DebugLevel;
1504:
1505: Debug(9, "Making initial lond connection for ".$RemoteHost);
1506:
1507: # Setup the initial server connection:
1508:
1509: # &MakeLondConnection(); // let first work requirest do it.
1510:
1511:
1512: Debug(9,"Entering event loop");
1513: my $ret = Event::loop(); # Start the main event loop.
1514:
1515:
1516: die "Main event loop exited!!!";
1517: }
1518:
1519: # Create a new child for host passed in:
1520:
1521: sub CreateChild {
1522: my $sigset = POSIX::SigSet->new(SIGINT);
1523: sigprocmask(SIG_BLOCK, $sigset);
1524: my $host = shift;
1525: $RemoteHost = $host;
1526: Log("CRITICAL", "Forking server for ".$host);
1527: my $pid = fork;
1528: if($pid) { # Parent
1529: $RemoteHost = "Parent";
1530: $ChildHash{$pid} = $host;
1531: $HostToPid{$host}= $pid;
1532: sigprocmask(SIG_UNBLOCK, $sigset);
1533:
1534: } else { # child.
1535: ShowStatus("Connected to ".$RemoteHost);
1536: $SIG{INT} = 'DEFAULT';
1537: sigprocmask(SIG_UNBLOCK, $sigset);
1538: ChildProcess; # Does not return.
1539: }
1540:
1541: }
1542: #
1543: # Parent process logic pass 1:
1544: # For each entry in the hosts table, we will
1545: # fork off an instance of ChildProcess to service the transactions
1546: # to that host. Each pid will be entered in a global hash
1547: # with the value of the key, the host.
1548: # The parent will then enter a loop to wait for process exits.
1549: # Each exit gets logged and the child gets restarted.
1550: #
1551:
1552: #
1553: # Fork and start in new session so hang-up isn't going to
1554: # happen without intent.
1555: #
1556:
1557:
1558:
1559:
1560:
1561:
1562: ShowStatus("Forming new session");
1563: my $childpid = fork;
1564: if ($childpid != 0) {
1565: sleep 4; # Give child a chacne to break to
1566: exit 0; # a new sesion.
1567: }
1568: #
1569: # Write my pid into the pid file so I can be located
1570: #
1571:
1572: ShowStatus("Parent writing pid file:");
1573: my $execdir = $perlvar{'lonDaemons'};
1574: open (PIDSAVE, ">$execdir/logs/lonc.pid");
1575: print PIDSAVE "$$\n";
1576: close(PIDSAVE);
1577:
1578:
1579:
1580: if (POSIX::setsid() < 0) {
1581: print "Could not create new session\n";
1582: exit -1;
1583: }
1584:
1585: ShowStatus("Forking node servers");
1586:
1587: Log("CRITICAL", "--------------- Starting children ---------------");
1588:
1589: my $HostIterator = LondConnection::GetHostIterator;
1590: while (! $HostIterator->end()) {
1591:
1592: my $hostentryref = $HostIterator->get();
1593: CreateChild($hostentryref->[0]);
1594: $HostHash{$hostentryref->[0]} = $hostentryref->[4];
1595: $HostIterator->next();
1596: }
1597: $RemoteHost = "Parent Server";
1598:
1599: # Maintain the population:
1600:
1601: ShowStatus("Parent keeping the flock");
1602:
1603: #
1604: # Set up parent signals:
1605: #
1606:
1607: $SIG{INT} = \&Terminate;
1608: $SIG{TERM} = \&Terminate;
1609: $SIG{HUP} = \&Restart;
1610: $SIG{USR1} = \&CheckKids;
1611: $SIG{USR2} = \&UpdateKids; # LonManage update request.
1612:
1613: while(1) {
1614: my $deadchild = wait();
1615: if(exists $ChildHash{$deadchild}) { # need to restart.
1616: my $deadhost = $ChildHash{$deadchild};
1617: delete($HostToPid{$deadhost});
1618: delete($ChildHash{$deadchild});
1619: Log("WARNING","Lost child pid= ".$deadchild.
1620: "Connected to host ".$deadhost);
1621: Log("INFO", "Restarting child procesing ".$deadhost);
1622: CreateChild($deadhost);
1623: }
1624: }
1625:
1626:
1627:
1628: =pod
1629:
1630: =head1 CheckKids
1631:
1632: Since kids do not die as easily in this implementation
1633: as the previous one, there is no need to restart the
1634: dead ones (all dead kids get restarted when they die!!)
1635: The only thing this function does is to pass USR1 to the
1636: kids so that they report their status.
1637:
1638: =cut
1639:
1640: sub CheckKids {
1641: Debug(2, "Checking status of children");
1642: my $docdir = $perlvar{'lonDocRoot'};
1643: my $fh = IO::File->new(">$docdir/lon-status/loncstatus.txt");
1644: my $now=time;
1645: my $local=localtime($now);
1646: print $fh "LONC status $local - parent $$ \n\n";
1647: foreach my $pid (keys %ChildHash) {
1648: Debug(2, "Sending USR1 -> $pid");
1649: kill 'USR1' => $pid; # Tell Child to report status.
1650: sleep 1; # Wait so file doesn't intermix.
1651: }
1652: }
1653:
1654: =pod
1655:
1656: =head1 UpdateKids
1657:
1658: parent's SIGUSR2 handler. This handler:
1659:
1660: =item
1661:
1662: Rereads the hosts file.
1663:
1664: =item
1665:
1666: Kills off (via sigint) children for hosts that have disappeared.
1667:
1668: =item
1669:
1670: QUITs children for hosts that already exist (this just forces a status display
1671: and resets the connection retry count for that host.
1672:
1673: =item
1674:
1675: Starts new children for hosts that have been added to the hosts.tab file since
1676: the start of the master program and maintains them.
1677:
1678: =cut
1679:
1680: sub UpdateKids {
1681:
1682: Log("INFO", "Updating connections via SIGUSR2");
1683:
1684: # Just in case we need to kill our own lonc, we wait a few seconds to
1685: # give it a chance to receive and relay lond's response to the
1686: # re-init command.
1687: #
1688:
1689: sleep(2); # Wait a couple of seconds.
1690:
1691: my %hosts; # Indexed by loncapa hostname, value=ip.
1692:
1693: # Need to re-read the host table:
1694:
1695:
1696: LondConnection::ReadConfig();
1697: my $I = LondConnection::GetHostIterator;
1698: while (! $I->end()) {
1699: my $item = $I->get();
1700: $hosts{$item->[0]} = $item->[4];
1701: $I->next();
1702: }
1703:
1704: # The logic below is written for clarity not for efficiency.
1705: # Since I anticipate that this function is only rarely called, that's
1706: # appropriate. There are certainly ways to combine the loops below,
1707: # and anyone wishing to obscure the logic is welcome to go for it.
1708: # Note that we don't re-direct sigchild. Instead we do what's needed
1709: # to the data structures that keep track of children to ensure that
1710: # when sigchild is honored, no new child is born.
1711: #
1712:
1713: # For each existing child; if it's host doesn't exist, kill the child.
1714:
1715: foreach my $child (keys %ChildHash) {
1716: my $oldhost = $ChildHash{$child};
1717: if (!(exists $hosts{$oldhost})) {
1718: Log("CRITICAL", "Killing child for $oldhost host no longer exists");
1719: delete $ChildHash{$child};
1720: delete $HostToPid{$oldhost};
1721: kill 'QUIT' => $child;
1722: }
1723: }
1724: # For each remaining existing child; if it's host's ip has changed,
1725: # Restart the child on the new IP.
1726:
1727: foreach my $child (keys %ChildHash) {
1728: my $oldhost = $ChildHash{$child};
1729: my $oldip = $HostHash{$oldhost};
1730: if ($hosts{$oldhost} ne $oldip) {
1731:
1732: # kill the old child.
1733:
1734: Log("CRITICAL", "Killing child for $oldhost host ip has changed...");
1735: delete $ChildHash{$child};
1736: delete $HostToPid{$oldhost};
1737: kill 'QUIT' => $child;
1738:
1739: # Do the book-keeping needed to start a new child on the
1740: # new ip.
1741:
1742: $HostHash{$oldhost} = $hosts{$oldhost};
1743: CreateChild($oldhost);
1744: }
1745: }
1746: # Finally, for each new host, not in the host hash, create a
1747: # enter the host and create a new child.
1748: # Force a status display of any existing process.
1749:
1750: foreach my $host (keys %hosts) {
1751: if(!(exists $HostHash{$host})) {
1752: Log("INFO", "New host $host discovered in hosts.tab...");
1753: $HostHash{$host} = $hosts{$host};
1754: CreateChild($host);
1755: } else {
1756: kill 'HUP' => $HostToPid{$host}; # status display.
1757: }
1758: }
1759: }
1760:
1761:
1762: =pod
1763:
1764: =head1 Restart
1765:
1766: Signal handler for HUP... all children are killed and
1767: we self restart. This is an el-cheapo way to re read
1768: the config file.
1769:
1770: =cut
1771:
1772: sub Restart {
1773: &KillThemAll; # First kill all the children.
1774: Log("CRITICAL", "Restarting");
1775: my $execdir = $perlvar{'lonDaemons'};
1776: unlink("$execdir/logs/lonc.pid");
1777: exec("$execdir/lonc");
1778: }
1779:
1780: =pod
1781:
1782: =head1 KillThemAll
1783:
1784: Signal handler that kills all children by sending them a
1785: SIGHUP. Responds to sigint and sigterm.
1786:
1787: =cut
1788:
1789: sub KillThemAll {
1790: Debug(2, "Kill them all!!");
1791: local($SIG{CHLD}) = 'IGNORE'; # Our children >will< die.
1792: foreach my $pid (keys %ChildHash) {
1793: my $serving = $ChildHash{$pid};
1794: Debug(2, "Killing lonc for $serving pid = $pid");
1795: ShowStatus("Killing lonc for $serving pid = $pid");
1796: Log("CRITICAL", "Killing lonc for $serving pid = $pid");
1797: kill 'QUIT' => $pid;
1798: delete($ChildHash{$pid});
1799: }
1800: my $execdir = $perlvar{'lonDaemons'};
1801: unlink("$execdir/logs/lonc.pid");
1802:
1803: }
1804:
1805: =pod
1806:
1807: =head1 Terminate
1808:
1809: Terminate the system.
1810:
1811: =cut
1812:
1813: sub Terminate {
1814: KillThemAll;
1815: Log("CRITICAL","Master process exiting");
1816: exit 0;
1817:
1818: }
1819: =pod
1820:
1821: =head1 Theory
1822:
1823: The event class is used to build this as a single process with an
1824: event driven model. The following events are handled:
1825:
1826: =item UNIX Socket connection Received
1827:
1828: =item Request data arrives on UNIX data transfer socket.
1829:
1830: =item lond connection becomes writable.
1831:
1832: =item timer fires at 1 second intervals.
1833:
1834: All sockets are run in non-blocking mode. Timeouts managed by the timer
1835: handler prevents hung connections.
1836:
1837: Key data structures:
1838:
1839: =item RequestQueue
1840:
1841: A queue of requests received from UNIX sockets that are
1842: waiting for a chance to be forwarded on a lond connection socket.
1843:
1844: =item ActiveConnections
1845:
1846: A hash of lond connections that have transactions in process that are
1847: available to be timed out.
1848:
1849: =item ActiveTransactions
1850:
1851: A hash indexed by lond connections that contain the client reply
1852: socket for each connection that has an active transaction on it.
1853:
1854: =item IdleConnections
1855:
1856: A hash of lond connections that have no work to do. These connections
1857: can be closed if they are idle for a long enough time.
1858:
1859: =cut
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