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