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