1: #!/usr/bin/perl
2: # The LearningOnline Network with CAPA
3: # lonc maintains the connections to remote computers
4: #
5: # $Id: loncnew,v 1.29 2003/10/21 14:24:42 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 1.29 2003/10/21 14:24:42 foxr
49: # Fix little typo that may explain growth of connections
50: #
51: # Revision 1.28 2003/10/14 15:36:21 albertel
52: # - making it easier to run loncnew,
53: # /etc/init.d/loncontrol startnew
54: # /etc/init.d/loncontrol restartnew
55: # will now start loncnew in place of lonc
56: #
57: # Revision 1.27 2003/10/07 11:23:03 foxr
58: # Installed and tested code to process reinit in parent server.
59: #
60: # Revision 1.26 2003/09/30 11:11:17 foxr
61: # Add book-keeping hashes to support the re-init procedure.
62: #
63: # Revision 1.25 2003/09/23 11:22:14 foxr
64: # Tested ability to receive sigusr2 This is now logged and must be
65: # properly implemented as a re-read of hosts and re-init of appropriate
66: # children.
67: #
68: # Revision 1.24 2003/09/16 09:46:42 foxr
69: # Added skeletal infrastructure to support SIGUSR2 update hosts request.
70: #
71: # Revision 1.23 2003/09/15 09:24:49 foxr
72: # Add use strict and fix all the fallout from that.
73: #
74: # Revision 1.22 2003/09/02 10:34:47 foxr
75: # - Fix errors in host dead detection logic (too many cases where the
76: # retries left were not getting incremented or just not checked).
77: # - Added some additional status to the ps axuww display:
78: # o Remaining retries on a host.
79: # o >>> DEAD <<< indicator if I've given up on a host.
80: # - Tested the SIGHUP will reset the retries remaining count (thanks to
81: # the above status stuff, and get allow the loncnew to re-try again
82: # on the host (thanks to the log).
83: #
84: # Revision 1.21 2003/08/26 09:19:51 foxr
85: # How embarrassing... put in the SocketTimeout function in loncnew and forgot
86: # to actually hook it into the LondTransaction. Added this to MakeLondConnection
87: # where it belongs... hopefully transactions (not just connection attempts) will
88: # timeout more speedily than the socket errors will catch it.
89: #
90: # Revision 1.20 2003/08/25 18:48:11 albertel
91: # - fixing a forgotten ;
92: #
93: # Revision 1.19 2003/08/19 09:31:46 foxr
94: # Get socket directory from configuration rather than the old hard coded test
95: # way that I forgot to un-hard code.
96: #
97: # Revision 1.18 2003/08/06 09:52:29 foxr
98: # Also needed to remember to fail in-flight transactions if their sends fail.
99: #
100: # Revision 1.17 2003/08/03 00:44:31 foxr
101: # 1. Correct handling of connection failure: Assume it means the host is
102: # unreachable and fail all of the queued transactions. Note that the
103: # inflight transactions should fail on their own time due either to timeout
104: # or send/receive failures.
105: # 2. Correct handling of logs for forced death signals. Pull the signal
106: # from the event watcher.
107: #
108: # Revision 1.16 2003/07/29 02:33:05 foxr
109: # Add SIGINT processing to child processes to toggle annoying trace mode
110: # on/off.. will try to use this to isolate the compute boud process issue.
111: #
112: # Revision 1.15 2003/07/15 02:07:05 foxr
113: # Added code for lonc/lond transaction timeouts. Who knows if it works right.
114: # The intent is for a timeout to fail any transaction in progress and kill
115: # off the sockt that timed out.
116: #
117: # Revision 1.14 2003/07/03 02:10:18 foxr
118: # Get all of the signals to work correctly.
119: #
120: # Revision 1.13 2003/07/02 01:31:55 foxr
121: # Added kill -HUP logic (restart).
122: #
123: # Revision 1.11 2003/06/25 01:54:44 foxr
124: # Fix more problems with transaction failure.
125: #
126: # Revision 1.10 2003/06/24 02:46:04 foxr
127: # Put a limit on the number of times we'll retry a connection.
128: # Start getting the signal stuff put in as well...note that need to get signals
129: # going or else the client will permanently give up on dead servers.
130: #
131: # Revision 1.9 2003/06/13 02:38:43 foxr
132: # Add logging in 'expected format'
133: #
134: # Revision 1.8 2003/06/11 02:04:35 foxr
135: # Support delayed transactions... this is done uniformly by encapsulating
136: # transactions in an object ... a LondTransaction that is implemented by
137: # LondTransaction.pm
138: #
139: # Revision 1.7 2003/06/03 01:59:39 foxr
140: # complete coding to support deferred transactions.
141: #
142: #
143: use strict;
144: use lib "/home/httpd/lib/perl/";
145: use lib "/home/foxr/newloncapa/types";
146: use Event qw(:DEFAULT );
147: use POSIX qw(:signal_h);
148: use POSIX;
149: use IO::Socket;
150: use IO::Socket::INET;
151: use IO::Socket::UNIX;
152: use IO::File;
153: use IO::Handle;
154: use Socket;
155: use Crypt::IDEA;
156: use LONCAPA::Queue;
157: use LONCAPA::Stack;
158: use LONCAPA::LondConnection;
159: use LONCAPA::LondTransaction;
160: use LONCAPA::Configuration;
161: use LONCAPA::HashIterator;
162:
163:
164: #
165: # Disable all signals we might receive from outside for now.
166: #
167:
168:
169: # Read the httpd configuration file to get perl variables
170: # normally set in apache modules:
171:
172: my $perlvarref = LONCAPA::Configuration::read_conf('loncapa.conf');
173: my %perlvar = %{$perlvarref};
174:
175: #
176: # parent and shared variables.
177:
178: my %ChildHash; # by pid -> host.
179: my %HostToPid; # By host -> pid.
180: my %HostHash; # by loncapaname -> IP.
181:
182:
183: my $MaxConnectionCount = 10; # Will get from config later.
184: my $ClientConnection = 0; # Uniquifier for client events.
185:
186: my $DebugLevel = 0;
187: my $NextDebugLevel= 2; # So Sigint can toggle this.
188: my $IdleTimeout= 3600; # Wait an hour before pruning connections.
189:
190: #
191: # The variables below are only used by the child processes.
192: #
193: my $RemoteHost; # Name of host child is talking to.
194: my $UnixSocketDir= $perlvar{'lonSockDir'};
195: my $IdleConnections = Stack->new(); # Set of idle connections
196: my %ActiveConnections; # Connections to the remote lond.
197: my %ActiveTransactions; # LondTransactions in flight.
198: my %ActiveClients; # Serial numbers of active clients by socket.
199: my $WorkQueue = Queue->new(); # Queue of pending transactions.
200: my $ConnectionCount = 0;
201: my $IdleSeconds = 0; # Number of seconds idle.
202: my $Status = ""; # Current status string.
203: my $RecentLogEntry = "";
204: my $ConnectionRetries=5; # Number of connection retries allowed.
205: my $ConnectionRetriesLeft=5; # Number of connection retries remaining.
206:
207: #
208: # The hash below gives the HTML format for log messages
209: # given a severity.
210: #
211: my %LogFormats;
212:
213: $LogFormats{"CRITICAL"} = "<font color=red>CRITICAL: %s</font>";
214: $LogFormats{"SUCCESS"} = "<font color=green>SUCCESS: %s</font>";
215: $LogFormats{"INFO"} = "<font color=yellow>INFO: %s</font>";
216: $LogFormats{"WARNING"} = "<font color=blue>WARNING: %s</font>";
217: $LogFormats{"DEFAULT"} = " %s ";
218:
219:
220:
221: =pod
222:
223: =head2 LogPerm
224:
225: Makes an entry into the permanent log file.
226:
227: =cut
228: sub LogPerm {
229: my $message=shift;
230: my $execdir=$perlvar{'lonDaemons'};
231: my $now=time;
232: my $local=localtime($now);
233: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
234: print $fh "$now:$message:$local\n";
235: }
236:
237: =pod
238:
239: =head2 Log
240:
241: Logs a message to the log file.
242: Parameters:
243:
244: =item severity
245:
246: One of CRITICAL, WARNING, INFO, SUCCESS used to select the
247: format string used to format the message. if the severity is
248: not a defined severity the Default format string is used.
249:
250: =item message
251:
252: The base message. In addtion to the format string, the message
253: will be appended to a string containing the name of our remote
254: host and the time will be formatted into the message.
255:
256: =cut
257:
258: sub Log {
259: my $severity = shift;
260: my $message = shift;
261:
262: if(!$LogFormats{$severity}) {
263: $severity = "DEFAULT";
264: }
265:
266: my $format = $LogFormats{$severity};
267:
268: # Put the window dressing in in front of the message format:
269:
270: my $now = time;
271: my $local = localtime($now);
272: my $finalformat = "$local ($$) [$RemoteHost] [$Status] ";
273: my $finalformat = $finalformat.$format."\n";
274:
275: # open the file and put the result.
276:
277: my $execdir = $perlvar{'lonDaemons'};
278: my $fh = IO::File->new(">>$execdir/logs/lonc.log");
279: my $msg = sprintf($finalformat, $message);
280: $RecentLogEntry = $msg;
281: print $fh $msg;
282:
283:
284: }
285:
286:
287: =pod
288:
289: =head2 GetPeerName
290:
291: Returns the name of the host that a socket object is connected to.
292:
293: =cut
294:
295: sub GetPeername {
296: my $connection = shift;
297: my $AdrFamily = shift;
298: my $peer = $connection->peername();
299: my $peerport;
300: my $peerip;
301: if($AdrFamily == AF_INET) {
302: ($peerport, $peerip) = sockaddr_in($peer);
303: my $peername = gethostbyaddr($peerip, $AdrFamily);
304: return $peername;
305: } elsif ($AdrFamily == AF_UNIX) {
306: my $peerfile;
307: ($peerfile) = sockaddr_un($peer);
308: return $peerfile;
309: }
310: }
311: #----------------------------- Timer management ------------------------
312: =pod
313:
314: =head2 Debug
315:
316: Invoked to issue a debug message.
317:
318: =cut
319:
320: sub Debug {
321: my $level = shift;
322: my $message = shift;
323: if ($level <= $DebugLevel) {
324: Log("INFO", "-Debug- $message host = $RemoteHost");
325: }
326: }
327:
328: sub SocketDump {
329: my $level = shift;
330: my $socket= shift;
331: if($level <= $DebugLevel) {
332: $socket->Dump();
333: }
334: }
335:
336: =pod
337:
338: =head2 ShowStatus
339:
340: Place some text as our pid status.
341: and as what we return in a SIGUSR1
342:
343: =cut
344: sub ShowStatus {
345: my $state = shift;
346: my $now = time;
347: my $local = localtime($now);
348: $Status = $local.": ".$state;
349: $0='lonc: '.$state.' '.$local;
350: }
351:
352: =pod
353:
354: =head 2 SocketTimeout
355:
356: Called when an action on the socket times out. The socket is
357: destroyed and any active transaction is failed.
358:
359:
360: =cut
361: sub SocketTimeout {
362: my $Socket = shift;
363:
364: KillSocket($Socket); # A transaction timeout also counts as
365: # a connection failure:
366: $ConnectionRetriesLeft--;
367: }
368:
369: =pod
370:
371: =head2 Tick
372:
373: Invoked each timer tick.
374:
375: =cut
376:
377:
378: sub Tick {
379: my $client;
380: if($ConnectionRetriesLeft > 0) {
381: ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
382: ." Retries remaining: ".$ConnectionRetriesLeft);
383: } else {
384: ShowStatus(GetServerHost()." >> DEAD <<");
385: }
386: # Is it time to prune connection count:
387:
388:
389: if($IdleConnections->Count() &&
390: ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
391: $IdleSeconds++;
392: if($IdleSeconds > $IdleTimeout) { # Prune a connection...
393: my $Socket = $IdleConnections->pop();
394: KillSocket($Socket);
395: }
396: } else {
397: $IdleSeconds = 0; # Reset idle count if not idle.
398: }
399: #
400: # For each inflight transaction, tick down its timeout counter.
401: #
402: foreach my $item (keys %ActiveTransactions) {
403: my $Socket = $ActiveTransactions{$item}->getServer();
404: $Socket->Tick();
405: }
406: # Do we have work in the queue, but no connections to service them?
407: # If so, try to make some new connections to get things going again.
408: #
409:
410: my $Requests = $WorkQueue->Count();
411: if (($ConnectionCount == 0) && ($Requests > 0)) {
412: if ($ConnectionRetriesLeft > 0) {
413: my $Connections = ($Requests <= $MaxConnectionCount) ?
414: $Requests : $MaxConnectionCount;
415: Debug(5,"Work but no connections, start ".$Connections." of them");
416: my $successCount = 0;
417: for (my $i =0; $i < $Connections; $i++) {
418: $successCount += MakeLondConnection();
419: }
420: if($successCount == 0) { # All connections failed:
421: Debug(5,"Work in queue failed to make any connectiouns\n");
422: EmptyQueue(); # Fail pending transactions with con_lost.
423: }
424: } else {
425: ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
426: Debug(5,"Work in queue, but gave up on connections..flushing\n");
427: EmptyQueue(); # Connections can't be established.
428: }
429:
430: }
431: }
432:
433: =pod
434:
435: =head2 SetupTimer
436:
437: Sets up a 1 per sec recurring timer event. The event handler is used to:
438:
439: =item
440:
441: Trigger timeouts on communications along active sockets.
442:
443: =item
444:
445: Trigger disconnections of idle sockets.
446:
447: =cut
448:
449: sub SetupTimer {
450: Debug(6, "SetupTimer");
451: Event->timer(interval => 1, debug => 1, cb => \&Tick );
452: }
453:
454: =pod
455:
456: =head2 ServerToIdle
457:
458: This function is called when a connection to the server is
459: ready for more work.
460:
461: If there is work in the Work queue the top element is dequeued
462: and the connection will start to work on it. If the work queue is
463: empty, the connection is pushed on the idle connection stack where
464: it will either get another work unit, or alternatively, if it sits there
465: long enough, it will be shut down and released.
466:
467: =cut
468:
469: sub ServerToIdle {
470: my $Socket = shift; # Get the socket.
471: delete($ActiveTransactions{$Socket}); # Server has no transaction
472:
473: &Debug(5, "Server to idle");
474:
475: # If there's work to do, start the transaction:
476:
477: my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
478: if ($reqdata ne undef) {
479: Debug(5, "Queue gave request data: ".$reqdata->getRequest());
480: &StartRequest($Socket, $reqdata);
481:
482: } else {
483:
484: # There's no work waiting, so push the server to idle list.
485: &Debug(5, "No new work requests, server connection going idle");
486: $IdleConnections->push($Socket);
487: }
488: }
489:
490: =pod
491:
492: =head2 ClientWritable
493:
494: Event callback for when a client socket is writable.
495:
496: This callback is established when a transaction reponse is
497: avaiable from lond. The response is forwarded to the unix socket
498: as it becomes writable in this sub.
499:
500: Parameters:
501:
502: =item Event
503:
504: The event that has been triggered. Event->w->data is
505: the data and Event->w->fd is the socket to write.
506:
507: =cut
508:
509: sub ClientWritable {
510: my $Event = shift;
511: my $Watcher = $Event->w;
512: my $Data = $Watcher->data;
513: my $Socket = $Watcher->fd;
514:
515: # Try to send the data:
516:
517: &Debug(6, "ClientWritable writing".$Data);
518: &Debug(9, "Socket is: ".$Socket);
519:
520: if($Socket->connected) {
521: my $result = $Socket->send($Data, 0);
522:
523: # $result undefined: the write failed.
524: # otherwise $result is the number of bytes written.
525: # Remove that preceding string from the data.
526: # If the resulting data is empty, destroy the watcher
527: # and set up a read event handler to accept the next
528: # request.
529:
530: &Debug(9,"Send result is ".$result." Defined: ".defined($result));
531: if($result ne undef) {
532: &Debug(9, "send result was defined");
533: if($result == length($Data)) { # Entire string sent.
534: &Debug(9, "ClientWritable data all written");
535: $Watcher->cancel();
536: #
537: # Set up to read next request from socket:
538:
539: my $descr = sprintf("Connection to lonc client %d",
540: $ActiveClients{$Socket});
541: Event->io(cb => \&ClientRequest,
542: poll => 'r',
543: desc => $descr,
544: data => "",
545: fd => $Socket);
546:
547: } else { # Partial string sent.
548: $Watcher->data(substr($Data, $result));
549: if($result == 0) { # client hung up on us!!
550: Log("INFO", "lonc pipe client hung up on us!");
551: $Watcher->cancel;
552: $Socket->shutdown(2);
553: $Socket->close();
554: }
555: }
556:
557: } else { # Error of some sort...
558:
559: # Some errnos are possible:
560: my $errno = $!;
561: if($errno == POSIX::EWOULDBLOCK ||
562: $errno == POSIX::EAGAIN ||
563: $errno == POSIX::EINTR) {
564: # No action taken?
565: } else { # Unanticipated errno.
566: &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
567: $Watcher->cancel; # Stop the watcher.
568: $Socket->shutdown(2); # Kill connection
569: $Socket->close(); # Close the socket.
570: }
571:
572: }
573: } else {
574: $Watcher->cancel(); # A delayed request...just cancel.
575: }
576: }
577:
578: =pod
579:
580: =head2 CompleteTransaction
581:
582: Called when the reply data has been received for a lond
583: transaction. The reply data must now be sent to the
584: ultimate client on the other end of the Unix socket. This is
585: done by setting up a writable event for the socket with the
586: data the reply data.
587:
588: Parameters:
589:
590: =item Socket
591:
592: Socket on which the lond transaction occured. This is a
593: LondConnection. The data received is in the TransactionReply member.
594:
595: =item Transaction
596:
597: The transaction that is being completed.
598:
599: =cut
600:
601: sub CompleteTransaction {
602: &Debug(5,"Complete transaction");
603: my $Socket = shift;
604: my $Transaction = shift;
605:
606: if (!$Transaction->isDeferred()) { # Normal transaction
607: my $data = $Socket->GetReply(); # Data to send.
608: StartClientReply($Transaction, $data);
609: } else { # Delete deferred transaction file.
610: Log("SUCCESS", "A delayed transaction was completed");
611: LogPerm("S:$Transaction->getClient() :".$Transaction->getRequest());
612: unlink $Transaction->getFile();
613: }
614: }
615: =pod
616: =head1 StartClientReply
617:
618: Initiates a reply to a client where the reply data is a parameter.
619:
620: =head2 parameters:
621:
622: =item Transaction
623:
624: The transaction for which we are responding to the client.
625:
626: =item data
627:
628: The data to send to apached client.
629:
630: =cut
631: sub StartClientReply {
632: my $Transaction = shift;
633: my $data = shift;
634:
635:
636: my $Client = $Transaction->getClient();
637:
638: &Debug(8," Reply was: ".$data);
639: my $Serial = $ActiveClients{$Client};
640: my $desc = sprintf("Connection to lonc client %d",
641: $Serial);
642: Event->io(fd => $Client,
643: poll => "w",
644: desc => $desc,
645: cb => \&ClientWritable,
646: data => $data);
647: }
648: =pod
649: =head2 FailTransaction
650:
651: Finishes a transaction with failure because the associated lond socket
652: disconnected. There are two possibilities:
653: - The transaction is deferred: in which case we just quietly
654: delete the transaction since there is no client connection.
655: - The transaction is 'live' in which case we initiate the sending
656: of "con_lost" to the client.
657:
658: Deleting the transaction means killing it from the
659: %ActiveTransactions hash.
660:
661: Parameters:
662:
663: =item client
664:
665: The LondTransaction we are failing.
666:
667: =cut
668:
669: sub FailTransaction {
670: my $transaction = shift;
671: Log("WARNING", "Failing transaction ".$transaction->getRequest());
672: Debug(5, "Failing transaction: ".$transaction->getRequest());
673: if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
674: my $client = $transaction->getClient();
675: Debug(5," Replying con_lost to ".$transaction->getRequest());
676: StartClientReply($transaction, "con_lost\n");
677: }
678: if($ConnectionRetriesLeft <= 0) {
679: Log("CRITICAL", "Host marked dead: ".GetServerHost());
680: }
681:
682: }
683:
684: =pod
685: =head1 EmptyQueue
686:
687: Fails all items in the work queue with con_lost.
688: Note that each item in the work queue is a transaction.
689:
690: =cut
691: sub EmptyQueue {
692: $ConnectionRetriesLeft--; # Counts as connection failure too.
693: while($WorkQueue->Count()) {
694: my $request = $WorkQueue->dequeue(); # This is a transaction
695: FailTransaction($request);
696: }
697: }
698:
699: =pod
700:
701: =head2 CloseAllLondConnections
702:
703: Close all connections open on lond prior to exit e.g.
704:
705: =cut
706: sub CloseAllLondConnections {
707: foreach my $Socket (keys %ActiveConnections) {
708: KillSocket($Socket);
709: }
710: }
711: =cut
712:
713: =pod
714:
715: =head2 KillSocket
716:
717: Destroys a socket. This function can be called either when a socket
718: has died of 'natural' causes or because a socket needs to be pruned due to
719: idleness. If the socket has died naturally, if there are no longer any
720: live connections a new connection is created (in case there are transactions
721: in the queue). If the socket has been pruned, it is never re-created.
722:
723: Parameters:
724:
725: =item Socket
726:
727: The socket to kill off.
728:
729: =item Restart
730:
731: nonzero if we are allowed to create a new connection.
732:
733:
734: =cut
735: sub KillSocket {
736: my $Socket = shift;
737:
738: Log("WARNING", "Shutting down a socket");
739: $Socket->Shutdown();
740:
741: # If the socket came from the active connection set,
742: # delete its transaction... note that FailTransaction should
743: # already have been called!!!
744: # otherwise it came from the idle set.
745: #
746:
747: if(exists($ActiveTransactions{$Socket})) {
748: delete ($ActiveTransactions{$Socket});
749: }
750: if(exists($ActiveConnections{$Socket})) {
751: delete($ActiveConnections{$Socket});
752: }
753: $ConnectionCount--;
754:
755: # If the connection count has gone to zero and there is work in the
756: # work queue, the work all gets failed with con_lost.
757: #
758: if($ConnectionCount == 0) {
759: EmptyQueue();
760: }
761: }
762:
763: =pod
764:
765: =head2 LondReadable
766:
767: This function is called whenever a lond connection
768: is readable. The action is state dependent:
769:
770: =head3 State=Initialized
771:
772: We''re waiting for the challenge, this is a no-op until the
773: state changes.
774:
775: =head3 State=Challenged
776:
777: The challenge has arrived we need to transition to Writable.
778: The connection must echo the challenge back.
779:
780: =head3 State=ChallengeReplied
781:
782: The challenge has been replied to. The we are receiveing the
783: 'ok' from the partner.
784:
785: =head3 State=RequestingKey
786:
787: The ok has been received and we need to send the request for
788: an encryption key. Transition to writable for that.
789:
790: =head3 State=ReceivingKey
791:
792: The the key has been requested, now we are reading the new key.
793:
794: =head3 State=Idle
795:
796: The encryption key has been negotiated or we have finished
797: reading data from the a transaction. If the callback data has
798: a client as well as the socket iformation, then we are
799: doing a transaction and the data received is relayed to the client
800: before the socket is put on the idle list.
801:
802: =head3 State=SendingRequest
803:
804: I do not think this state can be received here, but if it is,
805: the appropriate thing to do is to transition to writable, and send
806: the request.
807:
808: =head3 State=ReceivingReply
809:
810: We finished sending the request to the server and now transition
811: to readable to receive the reply.
812:
813: The parameter to this function are:
814:
815: The event. Implicit in this is the watcher and its data. The data
816: contains at least the lond connection object and, if a
817: transaction is in progress, the socket attached to the local client.
818:
819: =cut
820:
821: sub LondReadable {
822:
823: my $Event = shift;
824: my $Watcher = $Event->w;
825: my $Socket = $Watcher->data;
826: my $client = undef;
827:
828: &Debug(6,"LondReadable called state = ".$Socket->GetState());
829:
830:
831: my $State = $Socket->GetState(); # All action depends on the state.
832:
833: SocketDump(6, $Socket);
834: my $status = $Socket->Readable();
835:
836: &Debug(2, "Socket->Readable returned: $status");
837:
838: if($status != 0) {
839: # bad return from socket read. Currently this means that
840: # The socket has become disconnected. We fail the transaction.
841:
842: Log("WARNING",
843: "Lond connection lost.");
844: if(exists($ActiveTransactions{$Socket})) {
845: FailTransaction($ActiveTransactions{$Socket});
846: }
847: $Watcher->cancel();
848: KillSocket($Socket);
849: $ConnectionRetriesLeft--; # Counts as connection failure
850: return;
851: }
852: SocketDump(6,$Socket);
853:
854: $State = $Socket->GetState(); # Update in case of transition.
855: &Debug(6, "After read, state is ".$State);
856:
857: if($State eq "Initialized") {
858:
859:
860: } elsif ($State eq "ChallengeReceived") {
861: # The challenge must be echoed back; The state machine
862: # in the connection takes care of setting that up. Just
863: # need to transition to writable:
864:
865: $Watcher->cb(\&LondWritable);
866: $Watcher->poll("w");
867:
868: } elsif ($State eq "ChallengeReplied") {
869:
870:
871: } elsif ($State eq "RequestingKey") {
872: # The ok was received. Now we need to request the key
873: # That requires us to be writable:
874:
875: $Watcher->cb(\&LondWritable);
876: $Watcher->poll("w");
877:
878: } elsif ($State eq "ReceivingKey") {
879:
880: } elsif ($State eq "Idle") {
881: # If necessary, complete a transaction and then go into the
882: # idle queue.
883: # Note that a trasition to idle indicates a live lond
884: # on the other end so reset the connection retries.
885: #
886: $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
887: $Watcher->cancel();
888: if(exists($ActiveTransactions{$Socket})) {
889: Debug(5,"Completing transaction!!");
890: CompleteTransaction($Socket,
891: $ActiveTransactions{$Socket});
892: } else {
893: Log("SUCCESS", "Connection ".$ConnectionCount." to "
894: .$RemoteHost." now ready for action");
895: }
896: ServerToIdle($Socket); # Next work unit or idle.
897:
898: } elsif ($State eq "SendingRequest") {
899: # We need to be writable for this and probably don't belong
900: # here inthe first place.
901:
902: Deubg(6, "SendingRequest state encountered in readable");
903: $Watcher->poll("w");
904: $Watcher->cb(\&LondWritable);
905:
906: } elsif ($State eq "ReceivingReply") {
907:
908:
909: } else {
910: # Invalid state.
911: Debug(4, "Invalid state in LondReadable");
912: }
913: }
914:
915: =pod
916:
917: =head2 LondWritable
918:
919: This function is called whenever a lond connection
920: becomes writable while there is a writeable monitoring
921: event. The action taken is very state dependent:
922:
923: =head3 State = Connected
924:
925: The connection is in the process of sending the 'init' hailing to the
926: lond on the remote end. The connection object''s Writable member is
927: called. On error, ConnectionError is called to destroy the connection
928: and remove it from the ActiveConnections hash
929:
930: =head3 Initialized
931:
932: 'init' has been sent, writability monitoring is removed and
933: readability monitoring is started with LondReadable as the callback.
934:
935: =head3 ChallengeReceived
936:
937: The connection has received the who are you challenge from the remote
938: system, and is in the process of sending the challenge
939: response. Writable is called.
940:
941: =head3 ChallengeReplied
942:
943: The connection has replied to the initial challenge The we switch to
944: monitoring readability looking for the server to reply with 'ok'.
945:
946: =head3 RequestingKey
947:
948: The connection is in the process of requesting its encryption key.
949: Writable is called.
950:
951: =head3 ReceivingKey
952:
953: The connection has sent the request for a key. Switch to readability
954: monitoring to accept the key
955:
956: =head3 SendingRequest
957:
958: The connection is in the process of sending a request to the server.
959: This request is part of a client transaction. All the states until
960: now represent the client setup protocol. Writable is called.
961:
962: =head3 ReceivingReply
963:
964: The connection has sent a request. Now it must receive a reply.
965: Readability monitoring is requested.
966:
967: This function is an event handler and therefore receives as
968: a parameter the event that has fired. The data for the watcher
969: of this event is a reference to a list of one or two elements,
970: depending on state. The first (and possibly only) element is the
971: socket. The second (present only if a request is in progress)
972: is the socket on which to return a reply to the caller.
973:
974: =cut
975:
976: sub LondWritable {
977: my $Event = shift;
978: my $Watcher = $Event->w;
979: my $Socket = $Watcher->data;
980: my $State = $Socket->GetState();
981:
982: Debug(6,"LondWritable State = ".$State."\n");
983:
984:
985: # Figure out what to do depending on the state of the socket:
986:
987:
988:
989:
990: SocketDump(6,$Socket);
991:
992: if ($State eq "Connected") {
993:
994: if ($Socket->Writable() != 0) {
995: # The write resulted in an error.
996: # We'll treat this as if the socket got disconnected:
997: Log("WARNING", "Connection to ".$RemoteHost.
998: " has been disconnected");
999: FailTransaction($ActiveTransactions{$Socket});
1000: $Watcher->cancel();
1001: KillSocket($Socket);
1002: return;
1003: }
1004: # "init" is being sent...
1005:
1006:
1007: } elsif ($State eq "Initialized") {
1008:
1009: # Now that init was sent, we switch
1010: # to watching for readability:
1011:
1012: $Watcher->cb(\&LondReadable);
1013: $Watcher->poll("r");
1014:
1015: } elsif ($State eq "ChallengeReceived") {
1016: # We received the challenge, now we
1017: # are echoing it back. This is a no-op,
1018: # we're waiting for the state to change
1019:
1020: if($Socket->Writable() != 0) {
1021:
1022: $Watcher->cancel();
1023: KillSocket($Socket);
1024: return;
1025: }
1026:
1027: } elsif ($State eq "ChallengeReplied") {
1028: # The echo was sent back, so we switch
1029: # to watching readability.
1030:
1031: $Watcher->cb(\&LondReadable);
1032: $Watcher->poll("r");
1033:
1034: } elsif ($State eq "RequestingKey") {
1035: # At this time we're requesting the key.
1036: # again, this is essentially a no-op.
1037: # we'll write the next chunk until the
1038: # state changes.
1039:
1040: if($Socket->Writable() != 0) {
1041: # Write resulted in an error.
1042:
1043: $Watcher->cancel();
1044: KillSocket($Socket);
1045: return;
1046:
1047: }
1048: } elsif ($State eq "ReceivingKey") {
1049: # Now we need to wait for the key
1050: # to come back from the peer:
1051:
1052: $Watcher->cb(\&LondReadable);
1053: $Watcher->poll("r");
1054:
1055: } elsif ($State eq "SendingRequest") {
1056: # At this time we are sending a request to the
1057: # peer... write the next chunk:
1058:
1059: if($Socket->Writable() != 0) {
1060:
1061: if(exists($ActiveTransactions{$Socket})) {
1062: Debug(3, "Lond connection lost, failing transactions");
1063: FailTransaction($ActiveTransactions{$Socket});
1064: }
1065: $Watcher->cancel();
1066: KillSocket($Socket);
1067: return;
1068:
1069: }
1070:
1071: } elsif ($State eq "ReceivingReply") {
1072: # The send has completed. Wait for the
1073: # data to come in for a reply.
1074: Debug(8,"Writable sent request/receiving reply");
1075: $Watcher->cb(\&LondReadable);
1076: $Watcher->poll("r");
1077:
1078: } else {
1079: # Control only passes here on an error:
1080: # the socket state does not match any
1081: # of the known states... so an error
1082: # must be logged.
1083:
1084: &Debug(4, "Invalid socket state ".$State."\n");
1085: }
1086:
1087: }
1088: =pod
1089:
1090: =cut
1091: sub QueueDelayed {
1092: Debug(3,"QueueDelayed called");
1093:
1094: my $path = "$perlvar{'lonSockDir'}/delayed";
1095:
1096: Debug(4, "Delayed path: ".$path);
1097: opendir(DIRHANDLE, $path);
1098:
1099: my @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
1100: closedir(DIRHANDLE);
1101: my $dfname;
1102: my $reqfile;
1103: foreach $dfname (sort @alldelayed) {
1104: $reqfile = "$path/$dfname";
1105: Debug(4, "queueing ".$reqfile);
1106: my $Handle = IO::File->new($reqfile);
1107: my $cmd = <$Handle>;
1108: chomp $cmd; # There may or may not be a newline...
1109: $cmd = $cmd."\n"; # now for sure there's exactly one newline.
1110: my $Transaction = LondTransaction->new($cmd);
1111: $Transaction->SetDeferred($reqfile);
1112: QueueTransaction($Transaction);
1113: }
1114:
1115: }
1116:
1117: =pod
1118:
1119: =head2 MakeLondConnection
1120:
1121: Create a new lond connection object, and start it towards its initial
1122: idleness. Once idle, it becomes elligible to receive transactions
1123: from the work queue. If the work queue is not empty when the
1124: connection is completed and becomes idle, it will dequeue an entry and
1125: start off on it.
1126:
1127: =cut
1128:
1129: sub MakeLondConnection {
1130: Debug(4,"MakeLondConnection to ".GetServerHost()." on port "
1131: .GetServerPort());
1132:
1133: my $Connection = LondConnection->new(&GetServerHost(),
1134: &GetServerPort());
1135:
1136: if($Connection == undef) { # Needs to be more robust later.
1137: Log("CRITICAL","Failed to make a connection with lond.");
1138: $ConnectionRetriesLeft--;
1139: return 0; # Failure.
1140: } else {
1141:
1142: # The connection needs to have writability
1143: # monitored in order to send the init sequence
1144: # that starts the whole authentication/key
1145: # exchange underway.
1146: #
1147: my $Socket = $Connection->GetSocket();
1148: if($Socket == undef) {
1149: die "did not get a socket from the connection";
1150: } else {
1151: &Debug(9,"MakeLondConnection got socket: ".$Socket);
1152: }
1153:
1154: $Connection->SetTimeoutCallback(\&SocketTimeout);
1155:
1156: my $event = Event->io(fd => $Socket,
1157: poll => 'w',
1158: cb => \&LondWritable,
1159: data => $Connection,
1160: desc => 'Connection to lond server');
1161: $ActiveConnections{$Connection} = $event;
1162:
1163: $ConnectionCount++;
1164: Debug(4, "Connection count = ".$ConnectionCount);
1165: if($ConnectionCount == 1) { # First Connection:
1166: QueueDelayed;
1167: }
1168: Log("SUCESS", "Created connection ".$ConnectionCount
1169: ." to host ".GetServerHost());
1170: return 1; # Return success.
1171: }
1172:
1173: }
1174:
1175: =pod
1176:
1177: =head2 StartRequest
1178:
1179: Starts a lond request going on a specified lond connection.
1180: parameters are:
1181:
1182: =item $Lond
1183:
1184: Connection to the lond that will send the transaction and receive the
1185: reply.
1186:
1187: =item $Client
1188:
1189: Connection to the client that is making this request We got the
1190: request from this socket, and when the request has been relayed to
1191: lond and we get a reply back from lond it will get sent to this
1192: socket.
1193:
1194: =item $Request
1195:
1196: The text of the request to send.
1197:
1198: =cut
1199:
1200: sub StartRequest {
1201: my $Lond = shift;
1202: my $Request = shift; # This is a LondTransaction.
1203:
1204: Debug(6, "StartRequest: ".$Request->getRequest());
1205:
1206: my $Socket = $Lond->GetSocket();
1207:
1208: $Request->Activate($Lond);
1209: $ActiveTransactions{$Lond} = $Request;
1210:
1211: $Lond->InitiateTransaction($Request->getRequest());
1212: my $event = Event->io(fd => $Socket,
1213: poll => "w",
1214: cb => \&LondWritable,
1215: data => $Lond,
1216: desc => "lond transaction connection");
1217: $ActiveConnections{$Lond} = $event;
1218: Debug(8," Start Request made watcher data with ".$event->data."\n");
1219: }
1220:
1221: =pod
1222:
1223: =head2 QueueTransaction
1224:
1225: If there is an idle lond connection, it is put to work doing this
1226: transaction. Otherwise, the transaction is placed in the work queue.
1227: If placed in the work queue and the maximum number of connections has
1228: not yet been created, a new connection will be started. Our goal is
1229: to eventually have a sufficient number of connections that the work
1230: queue will typically be empty. parameters are:
1231:
1232: =item Socket
1233:
1234: open on the lonc client.
1235:
1236: =item Request
1237:
1238: data to send to the lond.
1239:
1240: =cut
1241:
1242: sub QueueTransaction {
1243:
1244: my $requestData = shift; # This is a LondTransaction.
1245: my $cmd = $requestData->getRequest();
1246:
1247: Debug(6,"QueueTransaction: ".$cmd);
1248:
1249: my $LondSocket = $IdleConnections->pop();
1250: if(!defined $LondSocket) { # Need to queue request.
1251: Debug(5,"Must queue...");
1252: $WorkQueue->enqueue($requestData);
1253: if($ConnectionCount < $MaxConnectionCount) {
1254: if($ConnectionRetriesLeft > 0) {
1255: Debug(5,"Starting additional lond connection");
1256: if(MakeLondConnection() == 0) {
1257: EmptyQueue(); # Fail transactions, can't make connection.
1258: }
1259: } else {
1260: ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
1261: EmptyQueue(); # It's worse than that ... he's dead Jim.
1262: }
1263: }
1264: } else { # Can start the request:
1265: Debug(8,"Can start...");
1266: StartRequest($LondSocket, $requestData);
1267: }
1268: }
1269:
1270: #-------------------------- Lonc UNIX socket handling ---------------------
1271:
1272: =pod
1273:
1274: =head2 ClientRequest
1275: Callback that is called when data can be read from the UNIX domain
1276: socket connecting us with an apache server process.
1277:
1278: =cut
1279:
1280: sub ClientRequest {
1281: Debug(6, "ClientRequest");
1282: my $event = shift;
1283: my $watcher = $event->w;
1284: my $socket = $watcher->fd;
1285: my $data = $watcher->data;
1286: my $thisread;
1287:
1288: Debug(9, " Watcher named: ".$watcher->desc);
1289:
1290: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1291: Debug(8, "rcv: data length = ".length($thisread)
1292: ." read =".$thisread);
1293: unless (defined $rv && length($thisread)) {
1294: # Likely eof on socket.
1295: Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
1296: close($socket);
1297: $watcher->cancel();
1298: delete($ActiveClients{$socket});
1299: return;
1300: }
1301: Debug(8,"Data: ".$data." this read: ".$thisread);
1302: $data = $data.$thisread; # Append new data.
1303: $watcher->data($data);
1304: if($data =~ /(.*\n)/) { # Request entirely read.
1305: if($data eq "close_connection_exit\n") {
1306: Log("CRITICAL",
1307: "Request Close Connection ... exiting");
1308: CloseAllLondConnections();
1309: exit;
1310: }
1311: Debug(8, "Complete transaction received: ".$data);
1312: my $Transaction = LondTransaction->new($data);
1313: $Transaction->SetClient($socket);
1314: QueueTransaction($Transaction);
1315: $watcher->cancel(); # Done looking for input data.
1316: }
1317:
1318: }
1319:
1320:
1321: =pod
1322:
1323: =head2 NewClient
1324:
1325: Callback that is called when a connection is received on the unix
1326: socket for a new client of lonc. The callback is parameterized by the
1327: event.. which is a-priori assumed to be an io event, and therefore has
1328: an fd member that is the Listener socket. We Accept the connection
1329: and register a new event on the readability of that socket:
1330:
1331: =cut
1332:
1333: sub NewClient {
1334: Debug(6, "NewClient");
1335: my $event = shift; # Get the event parameters.
1336: my $watcher = $event->w;
1337: my $socket = $watcher->fd; # Get the event' socket.
1338: my $connection = $socket->accept(); # Accept the client connection.
1339: Debug(8,"Connection request accepted from "
1340: .GetPeername($connection, AF_UNIX));
1341:
1342:
1343: my $description = sprintf("Connection to lonc client %d",
1344: $ClientConnection);
1345: Debug(9, "Creating event named: ".$description);
1346: Event->io(cb => \&ClientRequest,
1347: poll => 'r',
1348: desc => $description,
1349: data => "",
1350: fd => $connection);
1351: $ActiveClients{$connection} = $ClientConnection;
1352: $ClientConnection++;
1353: }
1354:
1355: =pod
1356:
1357: =head2 GetLoncSocketPath
1358:
1359: Returns the name of the UNIX socket on which to listen for client
1360: connections.
1361:
1362: =cut
1363:
1364: sub GetLoncSocketPath {
1365: return $UnixSocketDir."/".GetServerHost();
1366: }
1367:
1368: =pod
1369:
1370: =head2 GetServerHost
1371:
1372: Returns the host whose lond we talk with.
1373:
1374: =cut
1375:
1376: sub GetServerHost {
1377: return $RemoteHost; # Setup by the fork.
1378: }
1379:
1380: =pod
1381:
1382: =head2 GetServerPort
1383:
1384: Returns the lond port number.
1385:
1386: =cut
1387:
1388: sub GetServerPort {
1389: return $perlvar{londPort};
1390: }
1391:
1392: =pod
1393:
1394: =head2 SetupLoncListener
1395:
1396: Setup a lonc listener event. The event is called when the socket
1397: becomes readable.. that corresponds to the receipt of a new
1398: connection. The event handler established will accept the connection
1399: (creating a communcations channel), that int turn will establish
1400: another event handler to subess requests.
1401:
1402: =cut
1403:
1404: sub SetupLoncListener {
1405:
1406: my $socket;
1407: my $SocketName = GetLoncSocketPath();
1408: unlink($SocketName);
1409: unless ($socket =IO::Socket::UNIX->new(Local => $SocketName,
1410: Listen => 10,
1411: Type => SOCK_STREAM)) {
1412: die "Failed to create a lonc listner socket";
1413: }
1414: Event->io(cb => \&NewClient,
1415: poll => 'r',
1416: desc => 'Lonc listener Unix Socket',
1417: fd => $socket);
1418: }
1419:
1420: =pod
1421:
1422: =head2 ChildStatus
1423:
1424: Child USR1 signal handler to report the most recent status
1425: into the status file.
1426:
1427: We also use this to reset the retries count in order to allow the
1428: client to retry connections with a previously dead server.
1429: =cut
1430: sub ChildStatus {
1431: my $event = shift;
1432: my $watcher = $event->w;
1433:
1434: Debug(2, "Reporting child status because : ".$watcher->data);
1435: my $docdir = $perlvar{'lonDocRoot'};
1436: my $fh = IO::File->new(">>$docdir/lon-status/loncstatus.txt");
1437: print $fh $$."\t".$RemoteHost."\t".$Status."\t".
1438: $RecentLogEntry."\n";
1439: $ConnectionRetriesLeft = $ConnectionRetries;
1440: }
1441:
1442: =pod
1443:
1444: =head2 SignalledToDeath
1445:
1446: Called in response to a signal that causes a chid process to die.
1447:
1448: =cut
1449:
1450:
1451: sub SignalledToDeath {
1452: my $event = shift;
1453: my $watcher= $event->w;
1454:
1455: Debug(2,"Signalled to death! via ".$watcher->data);
1456: my ($signal) = $watcher->data;
1457: chomp($signal);
1458: Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "
1459: ."died through "."\"$signal\"");
1460: LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
1461: ."\"$signal\"");
1462: exit 0;
1463:
1464: }
1465:
1466: =head2 ToggleDebug
1467:
1468: This sub toggles trace debugging on and off.
1469:
1470: =cut
1471:
1472: sub ToggleDebug {
1473: my $Current = $DebugLevel;
1474: $DebugLevel = $NextDebugLevel;
1475: $NextDebugLevel = $Current;
1476:
1477: Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
1478:
1479: }
1480:
1481: =head2 ChildProcess
1482:
1483: This sub implements a child process for a single lonc daemon.
1484:
1485: =cut
1486:
1487: sub ChildProcess {
1488:
1489:
1490: #
1491: # Signals must be handled by the Event framework...
1492: #
1493:
1494: Event->signal(signal => "QUIT",
1495: cb => \&SignalledToDeath,
1496: data => "QUIT");
1497: Event->signal(signal => "HUP",
1498: cb => \&ChildStatus,
1499: data => "HUP");
1500: Event->signal(signal => "USR1",
1501: cb => \&ChildStatus,
1502: data => "USR1");
1503: Event->signal(signal => "INT",
1504: cb => \&ToggleDebug,
1505: data => "INT");
1506:
1507: SetupTimer();
1508:
1509: SetupLoncListener();
1510:
1511: $Event::Debuglevel = $DebugLevel;
1512:
1513: Debug(9, "Making initial lond connection for ".$RemoteHost);
1514:
1515: # Setup the initial server connection:
1516:
1517: # &MakeLondConnection(); // let first work requirest do it.
1518:
1519:
1520: Debug(9,"Entering event loop");
1521: my $ret = Event::loop(); # Start the main event loop.
1522:
1523:
1524: die "Main event loop exited!!!";
1525: }
1526:
1527: # Create a new child for host passed in:
1528:
1529: sub CreateChild {
1530: my $sigset = POSIX::SigSet->new(SIGINT);
1531: sigprocmask(SIG_BLOCK, $sigset);
1532: my $host = shift;
1533: $RemoteHost = $host;
1534: Log("CRITICAL", "Forking server for ".$host);
1535: my $pid = fork;
1536: if($pid) { # Parent
1537: $RemoteHost = "Parent";
1538: $ChildHash{$pid} = $host;
1539: $HostToPid{$host}= $pid;
1540: sigprocmask(SIG_UNBLOCK, $sigset);
1541:
1542: } else { # child.
1543: ShowStatus("Connected to ".$RemoteHost);
1544: $SIG{INT} = 'DEFAULT';
1545: sigprocmask(SIG_UNBLOCK, $sigset);
1546: ChildProcess; # Does not return.
1547: }
1548:
1549: }
1550: #
1551: # Parent process logic pass 1:
1552: # For each entry in the hosts table, we will
1553: # fork off an instance of ChildProcess to service the transactions
1554: # to that host. Each pid will be entered in a global hash
1555: # with the value of the key, the host.
1556: # The parent will then enter a loop to wait for process exits.
1557: # Each exit gets logged and the child gets restarted.
1558: #
1559:
1560: #
1561: # Fork and start in new session so hang-up isn't going to
1562: # happen without intent.
1563: #
1564:
1565:
1566:
1567:
1568:
1569:
1570: ShowStatus("Forming new session");
1571: my $childpid = fork;
1572: if ($childpid != 0) {
1573: sleep 4; # Give child a chacne to break to
1574: exit 0; # a new sesion.
1575: }
1576: #
1577: # Write my pid into the pid file so I can be located
1578: #
1579:
1580: ShowStatus("Parent writing pid file:");
1581: my $execdir = $perlvar{'lonDaemons'};
1582: open (PIDSAVE, ">$execdir/logs/lonc.pid");
1583: print PIDSAVE "$$\n";
1584: close(PIDSAVE);
1585:
1586:
1587:
1588: if (POSIX::setsid() < 0) {
1589: print "Could not create new session\n";
1590: exit -1;
1591: }
1592:
1593: ShowStatus("Forking node servers");
1594:
1595: Log("CRITICAL", "--------------- Starting children ---------------");
1596:
1597: my $HostIterator = LondConnection::GetHostIterator;
1598: while (! $HostIterator->end()) {
1599:
1600: my $hostentryref = $HostIterator->get();
1601: CreateChild($hostentryref->[0]);
1602: $HostHash{$hostentryref->[0]} = $hostentryref->[4];
1603: $HostIterator->next();
1604: }
1605: $RemoteHost = "Parent Server";
1606:
1607: # Maintain the population:
1608:
1609: ShowStatus("Parent keeping the flock");
1610:
1611: #
1612: # Set up parent signals:
1613: #
1614:
1615: $SIG{INT} = \&Terminate;
1616: $SIG{TERM} = \&Terminate;
1617: $SIG{HUP} = \&Restart;
1618: $SIG{USR1} = \&CheckKids;
1619: $SIG{USR2} = \&UpdateKids; # LonManage update request.
1620:
1621: while(1) {
1622: my $deadchild = wait();
1623: if(exists $ChildHash{$deadchild}) { # need to restart.
1624: my $deadhost = $ChildHash{$deadchild};
1625: delete($HostToPid{$deadhost});
1626: delete($ChildHash{$deadchild});
1627: Log("WARNING","Lost child pid= ".$deadchild.
1628: "Connected to host ".$deadhost);
1629: Log("INFO", "Restarting child procesing ".$deadhost);
1630: CreateChild($deadhost);
1631: }
1632: }
1633:
1634:
1635:
1636: =pod
1637:
1638: =head1 CheckKids
1639:
1640: Since kids do not die as easily in this implementation
1641: as the previous one, there is no need to restart the
1642: dead ones (all dead kids get restarted when they die!!)
1643: The only thing this function does is to pass USR1 to the
1644: kids so that they report their status.
1645:
1646: =cut
1647:
1648: sub CheckKids {
1649: Debug(2, "Checking status of children");
1650: my $docdir = $perlvar{'lonDocRoot'};
1651: my $fh = IO::File->new(">$docdir/lon-status/loncstatus.txt");
1652: my $now=time;
1653: my $local=localtime($now);
1654: print $fh "LONC status $local - parent $$ \n\n";
1655: foreach my $pid (keys %ChildHash) {
1656: Debug(2, "Sending USR1 -> $pid");
1657: kill 'USR1' => $pid; # Tell Child to report status.
1658: sleep 1; # Wait so file doesn't intermix.
1659: }
1660: }
1661:
1662: =pod
1663:
1664: =head1 UpdateKids
1665:
1666: parent's SIGUSR2 handler. This handler:
1667:
1668: =item
1669:
1670: Rereads the hosts file.
1671:
1672: =item
1673:
1674: Kills off (via sigint) children for hosts that have disappeared.
1675:
1676: =item
1677:
1678: QUITs children for hosts that already exist (this just forces a status display
1679: and resets the connection retry count for that host.
1680:
1681: =item
1682:
1683: Starts new children for hosts that have been added to the hosts.tab file since
1684: the start of the master program and maintains them.
1685:
1686: =cut
1687:
1688: sub UpdateKids {
1689:
1690: Log("INFO", "Updating connections via SIGUSR2");
1691:
1692: # Just in case we need to kill our own lonc, we wait a few seconds to
1693: # give it a chance to receive and relay lond's response to the
1694: # re-init command.
1695: #
1696:
1697: sleep(2); # Wait a couple of seconds.
1698:
1699: my %hosts; # Indexed by loncapa hostname, value=ip.
1700:
1701: # Need to re-read the host table:
1702:
1703:
1704: LondConnection::ReadConfig();
1705: my $I = LondConnection::GetHostIterator;
1706: while (! $I->end()) {
1707: my $item = $I->get();
1708: $hosts{$item->[0]} = $item->[4];
1709: $I->next();
1710: }
1711:
1712: # The logic below is written for clarity not for efficiency.
1713: # Since I anticipate that this function is only rarely called, that's
1714: # appropriate. There are certainly ways to combine the loops below,
1715: # and anyone wishing to obscure the logic is welcome to go for it.
1716: # Note that we don't re-direct sigchild. Instead we do what's needed
1717: # to the data structures that keep track of children to ensure that
1718: # when sigchild is honored, no new child is born.
1719: #
1720:
1721: # For each existing child; if it's host doesn't exist, kill the child.
1722:
1723: foreach my $child (keys %ChildHash) {
1724: my $oldhost = $ChildHash{$child};
1725: if (!(exists $hosts{$oldhost})) {
1726: Log("CRITICAL", "Killing child for $oldhost host no longer exists");
1727: delete $ChildHash{$child};
1728: delete $HostToPid{$oldhost};
1729: kill 'QUIT' => $child;
1730: }
1731: }
1732: # For each remaining existing child; if it's host's ip has changed,
1733: # Restart the child on the new IP.
1734:
1735: foreach my $child (keys %ChildHash) {
1736: my $oldhost = $ChildHash{$child};
1737: my $oldip = $HostHash{$oldhost};
1738: if ($hosts{$oldhost} ne $oldip) {
1739:
1740: # kill the old child.
1741:
1742: Log("CRITICAL", "Killing child for $oldhost host ip has changed...");
1743: delete $ChildHash{$child};
1744: delete $HostToPid{$oldhost};
1745: kill 'QUIT' => $child;
1746:
1747: # Do the book-keeping needed to start a new child on the
1748: # new ip.
1749:
1750: $HostHash{$oldhost} = $hosts{$oldhost};
1751: CreateChild($oldhost);
1752: }
1753: }
1754: # Finally, for each new host, not in the host hash, create a
1755: # enter the host and create a new child.
1756: # Force a status display of any existing process.
1757:
1758: foreach my $host (keys %hosts) {
1759: if(!(exists $HostHash{$host})) {
1760: Log("INFO", "New host $host discovered in hosts.tab...");
1761: $HostHash{$host} = $hosts{$host};
1762: CreateChild($host);
1763: } else {
1764: kill 'HUP' => $HostToPid{$host}; # status display.
1765: }
1766: }
1767: }
1768:
1769:
1770: =pod
1771:
1772: =head1 Restart
1773:
1774: Signal handler for HUP... all children are killed and
1775: we self restart. This is an el-cheapo way to re read
1776: the config file.
1777:
1778: =cut
1779:
1780: sub Restart {
1781: &KillThemAll; # First kill all the children.
1782: Log("CRITICAL", "Restarting");
1783: my $execdir = $perlvar{'lonDaemons'};
1784: unlink("$execdir/logs/lonc.pid");
1785: exec("$execdir/loncnew");
1786: }
1787:
1788: =pod
1789:
1790: =head1 KillThemAll
1791:
1792: Signal handler that kills all children by sending them a
1793: SIGHUP. Responds to sigint and sigterm.
1794:
1795: =cut
1796:
1797: sub KillThemAll {
1798: Debug(2, "Kill them all!!");
1799: local($SIG{CHLD}) = 'IGNORE'; # Our children >will< die.
1800: foreach my $pid (keys %ChildHash) {
1801: my $serving = $ChildHash{$pid};
1802: Debug(2, "Killing lonc for $serving pid = $pid");
1803: ShowStatus("Killing lonc for $serving pid = $pid");
1804: Log("CRITICAL", "Killing lonc for $serving pid = $pid");
1805: kill 'QUIT' => $pid;
1806: delete($ChildHash{$pid});
1807: }
1808: my $execdir = $perlvar{'lonDaemons'};
1809: unlink("$execdir/logs/lonc.pid");
1810:
1811: }
1812:
1813: =pod
1814:
1815: =head1 Terminate
1816:
1817: Terminate the system.
1818:
1819: =cut
1820:
1821: sub Terminate {
1822: KillThemAll;
1823: Log("CRITICAL","Master process exiting");
1824: exit 0;
1825:
1826: }
1827: =pod
1828:
1829: =head1 Theory
1830:
1831: The event class is used to build this as a single process with an
1832: event driven model. The following events are handled:
1833:
1834: =item UNIX Socket connection Received
1835:
1836: =item Request data arrives on UNIX data transfer socket.
1837:
1838: =item lond connection becomes writable.
1839:
1840: =item timer fires at 1 second intervals.
1841:
1842: All sockets are run in non-blocking mode. Timeouts managed by the timer
1843: handler prevents hung connections.
1844:
1845: Key data structures:
1846:
1847: =item RequestQueue
1848:
1849: A queue of requests received from UNIX sockets that are
1850: waiting for a chance to be forwarded on a lond connection socket.
1851:
1852: =item ActiveConnections
1853:
1854: A hash of lond connections that have transactions in process that are
1855: available to be timed out.
1856:
1857: =item ActiveTransactions
1858:
1859: A hash indexed by lond connections that contain the client reply
1860: socket for each connection that has an active transaction on it.
1861:
1862: =item IdleConnections
1863:
1864: A hash of lond connections that have no work to do. These connections
1865: can be closed if they are idle for a long enough time.
1866:
1867: =cut
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