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[LON-CAPA] /
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loncnew
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1.58:
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Wed Sep 22 10:34:44 2004 UTC (19 years, 7 months ago) by
foxr
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MAIN
CVS tags:
HEAD
Continue adding latent support for child exit when connection count
trimmed to zero: Allow default host for GetLoncSocketPath and
SetupLoncListener to be optionally parameterized with a loncapa
hostname. The actual server processes will typically not parameterize
these, but the parent/master will.
1: #!/usr/bin/perl
2: # The LearningOnline Network with CAPA
3: # lonc maintains the connections to remote computers
4: #
5: # $Id: loncnew,v 1.58 2004/09/22 10:34:44 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. (done)
39: # - Add Signal handling - HUP restarts. USR1 status report. (done)
40: # - Add Configuration file I/O (done).
41: # - Add management/status request interface. (done)
42: # - Add deferred request capability. (done)
43: # - Detect transmission timeouts. (done)
44: #
45:
46: use strict;
47: use lib "/home/httpd/lib/perl/";
48: use Event qw(:DEFAULT );
49: use POSIX qw(:signal_h);
50: use POSIX;
51: use IO::Socket;
52: use IO::Socket::INET;
53: use IO::Socket::UNIX;
54: use IO::File;
55: use IO::Handle;
56: use Socket;
57: use Crypt::IDEA;
58: use LONCAPA::Queue;
59: use LONCAPA::Stack;
60: use LONCAPA::LondConnection;
61: use LONCAPA::LondTransaction;
62: use LONCAPA::Configuration;
63: use LONCAPA::HashIterator;
64:
65:
66: # Read the httpd configuration file to get perl variables
67: # normally set in apache modules:
68:
69: my $perlvarref = LONCAPA::Configuration::read_conf('loncapa.conf');
70: my %perlvar = %{$perlvarref};
71:
72: #
73: # parent and shared variables.
74:
75: my %ChildHash; # by pid -> host.
76: my %HostToPid; # By host -> pid.
77: my %HostHash; # by loncapaname -> IP.
78:
79:
80: my $MaxConnectionCount = 10; # Will get from config later.
81: my $ClientConnection = 0; # Uniquifier for client events.
82:
83: my $DebugLevel = 0;
84: my $NextDebugLevel= 2; # So Sigint can toggle this.
85: my $IdleTimeout= 600; # Wait 10 minutes before pruning connections.
86:
87: my $LogTransactions = 0; # When True, all transactions/replies get logged.
88:
89: #
90: # The variables below are only used by the child processes.
91: #
92: my $RemoteHost; # Name of host child is talking to.
93: my $UnixSocketDir= $perlvar{'lonSockDir'};
94: my $IdleConnections = Stack->new(); # Set of idle connections
95: my %ActiveConnections; # Connections to the remote lond.
96: my %ActiveTransactions; # LondTransactions in flight.
97: my %ActiveClients; # Serial numbers of active clients by socket.
98: my $WorkQueue = Queue->new(); # Queue of pending transactions.
99: my $ConnectionCount = 0;
100: my $IdleSeconds = 0; # Number of seconds idle.
101: my $Status = ""; # Current status string.
102: my $RecentLogEntry = "";
103: my $ConnectionRetries=2; # Number of connection retries allowed.
104: my $ConnectionRetriesLeft=2; # Number of connection retries remaining.
105: my $LondVersion = "unknown"; # Version of lond we talk with.
106: my $KeyMode = ""; # e.g. ssl, local, insecure from last connect.
107: my $LondConnecting = 0; # True when a connection is being built.
108:
109: my $DieWhenIdle = 0; # When true children die when trimmed -> 0.
110:
111: #
112: # The hash below gives the HTML format for log messages
113: # given a severity.
114: #
115: my %LogFormats;
116:
117: $LogFormats{"CRITICAL"} = "<font color='red'>CRITICAL: %s</font>";
118: $LogFormats{"SUCCESS"} = "<font color='green'>SUCCESS: %s</font>";
119: $LogFormats{"INFO"} = "<font color='yellow'>INFO: %s</font>";
120: $LogFormats{"WARNING"} = "<font color='blue'>WARNING: %s</font>";
121: $LogFormats{"DEFAULT"} = " %s ";
122:
123:
124: # UpdateStatus;
125: # Update the idle status display to show how many connections
126: # are left, retries and other stuff.
127: #
128: sub UpdateStatus {
129: if ($ConnectionRetriesLeft > 0) {
130: ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
131: ." Retries remaining: ".$ConnectionRetriesLeft
132: ." ($KeyMode)");
133: } else {
134: ShowStatus(GetServerHost()." >> DEAD <<");
135: }
136: }
137:
138:
139: =pod
140:
141: =head2 LogPerm
142:
143: Makes an entry into the permanent log file.
144:
145: =cut
146: sub LogPerm {
147: my $message=shift;
148: my $execdir=$perlvar{'lonDaemons'};
149: my $now=time;
150: my $local=localtime($now);
151: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
152: print $fh "$now:$message:$local\n";
153: }
154:
155: =pod
156:
157: =head2 Log
158:
159: Logs a message to the log file.
160: Parameters:
161:
162: =item severity
163:
164: One of CRITICAL, WARNING, INFO, SUCCESS used to select the
165: format string used to format the message. if the severity is
166: not a defined severity the Default format string is used.
167:
168: =item message
169:
170: The base message. In addtion to the format string, the message
171: will be appended to a string containing the name of our remote
172: host and the time will be formatted into the message.
173:
174: =cut
175:
176: sub Log {
177:
178: my ($severity, $message) = @_;
179:
180: if(!$LogFormats{$severity}) {
181: $severity = "DEFAULT";
182: }
183:
184: my $format = $LogFormats{$severity};
185:
186: # Put the window dressing in in front of the message format:
187:
188: my $now = time;
189: my $local = localtime($now);
190: my $finalformat = "$local ($$) [$RemoteHost] [$Status] ";
191: my $finalformat = $finalformat.$format."\n";
192:
193: # open the file and put the result.
194:
195: my $execdir = $perlvar{'lonDaemons'};
196: my $fh = IO::File->new(">>$execdir/logs/lonc.log");
197: my $msg = sprintf($finalformat, $message);
198: $RecentLogEntry = $msg;
199: print $fh $msg;
200:
201:
202: }
203:
204:
205: =pod
206:
207: =head2 GetPeerName
208:
209: Returns the name of the host that a socket object is connected to.
210:
211: =cut
212:
213: sub GetPeername {
214:
215:
216: my ($connection, $AdrFamily) = @_;
217:
218: my $peer = $connection->peername();
219: my $peerport;
220: my $peerip;
221: if($AdrFamily == AF_INET) {
222: ($peerport, $peerip) = sockaddr_in($peer);
223: my $peername = gethostbyaddr($peerip, $AdrFamily);
224: return $peername;
225: } elsif ($AdrFamily == AF_UNIX) {
226: my $peerfile;
227: ($peerfile) = sockaddr_un($peer);
228: return $peerfile;
229: }
230: }
231: =pod
232:
233: =head2 Debug
234:
235: Invoked to issue a debug message.
236:
237: =cut
238:
239: sub Debug {
240:
241: my ($level, $message) = @_;
242:
243: if ($level <= $DebugLevel) {
244: Log("INFO", "-Debug- $message host = $RemoteHost");
245: }
246: }
247:
248: sub SocketDump {
249:
250: my ($level, $socket) = @_;
251:
252: if($level <= $DebugLevel) {
253: $socket->Dump(-1); # Ensure it will get dumped.
254: }
255: }
256:
257: =pod
258:
259: =head2 ShowStatus
260:
261: Place some text as our pid status.
262: and as what we return in a SIGUSR1
263:
264: =cut
265: sub ShowStatus {
266: my $state = shift;
267: my $now = time;
268: my $local = localtime($now);
269: $Status = $local.": ".$state;
270: $0='lonc: '.$state.' '.$local;
271: }
272:
273: =pod
274:
275: =head 2 SocketTimeout
276:
277: Called when an action on the socket times out. The socket is
278: destroyed and any active transaction is failed.
279:
280:
281: =cut
282: sub SocketTimeout {
283: my $Socket = shift;
284: Log("WARNING", "A socket timeout was detected");
285: Debug(5, " SocketTimeout called: ");
286: $Socket->Dump(0);
287: if(exists($ActiveTransactions{$Socket})) {
288: FailTransaction($ActiveTransactions{$Socket});
289: }
290: KillSocket($Socket); # A transaction timeout also counts as
291: # a connection failure:
292: $ConnectionRetriesLeft--;
293: if($ConnectionRetriesLeft <= 0) {
294: Log("CRITICAL", "Host marked DEAD: ".GetServerHost());
295: $LondConnecting = 0;
296: }
297:
298: }
299: #----------------------------- Timer management ------------------------
300:
301: =pod
302:
303: =head2 Tick
304:
305: Invoked each timer tick.
306:
307: =cut
308:
309:
310: sub Tick {
311: my ($Event) = @_;
312: my $clock_watcher = $Event->w;
313:
314: my $client;
315: UpdateStatus();
316:
317: # Is it time to prune connection count:
318:
319:
320: if($IdleConnections->Count() &&
321: ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
322: $IdleSeconds++;
323: if($IdleSeconds > $IdleTimeout) { # Prune a connection...
324: my $Socket = $IdleConnections->pop();
325: KillSocket($Socket);
326: $IdleSeconds = 0; # Otherwise all connections get trimmed to fast.
327: UpdateStatus();
328: if(($ConnectionCount == 0) && $DieWhenIdle) {
329: #
330: # Create a lock file since there will be a time window
331: # between our exit and the parent's picking up the listen
332: # during which no listens will be done on the
333: # lonnet client socket.
334: #
335: my $lock_file = GetLoncSocketPath().".lock";
336: open(LOCK,">$lock_file");
337: print LOCK "Contents not important";
338: close(LOCK);
339:
340: exit(0);
341: }
342: }
343: } else {
344: $IdleSeconds = 0; # Reset idle count if not idle.
345: }
346: #
347: # For each inflight transaction, tick down its timeout counter.
348: #
349:
350: foreach my $item (keys %ActiveConnections) {
351: my $State = $ActiveConnections{$item}->data->GetState();
352: if ($State ne 'Idle') {
353: Debug(5,"Ticking Socket $State $item");
354: $ActiveConnections{$item}->data->Tick();
355: }
356: }
357: # Do we have work in the queue, but no connections to service them?
358: # If so, try to make some new connections to get things going again.
359: #
360: # Note this code is dead now...
361: #
362: my $Requests = $WorkQueue->Count();
363: if (($ConnectionCount == 0) && ($Requests > 0) && (!$LondConnecting)) {
364: if ($ConnectionRetriesLeft > 0) {
365: Debug(5,"Work but no connections, Make a new one");
366: my $success;
367: $success = &MakeLondConnection;
368: if($success == 0) { # All connections failed:
369: Debug(5,"Work in queue failed to make any connectiouns\n");
370: EmptyQueue(); # Fail pending transactions with con_lost.
371: CloseAllLondConnections(); # Should all be closed but....
372: }
373: } else {
374: $LondConnecting = 0;
375: ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
376: Debug(5,"Work in queue, but gave up on connections..flushing\n");
377: EmptyQueue(); # Connections can't be established.
378: CloseAllLondConnections(); # Should all already be closed but...
379: }
380:
381: }
382: if ($ConnectionCount == 0) {
383: $KeyMode = "";
384: $clock_watcher->cancel();
385: }
386: }
387:
388: =pod
389:
390: =head2 SetupTimer
391:
392: Sets up a 1 per sec recurring timer event. The event handler is used to:
393:
394: =item
395:
396: Trigger timeouts on communications along active sockets.
397:
398: =item
399:
400: Trigger disconnections of idle sockets.
401:
402: =cut
403:
404: sub SetupTimer {
405: Debug(6, "SetupTimer");
406: Event->timer(interval => 1, cb => \&Tick );
407: }
408:
409: =pod
410:
411: =head2 ServerToIdle
412:
413: This function is called when a connection to the server is
414: ready for more work.
415:
416: If there is work in the Work queue the top element is dequeued
417: and the connection will start to work on it. If the work queue is
418: empty, the connection is pushed on the idle connection stack where
419: it will either get another work unit, or alternatively, if it sits there
420: long enough, it will be shut down and released.
421:
422: =cut
423:
424: sub ServerToIdle {
425: my $Socket = shift; # Get the socket.
426: $KeyMode = $Socket->{AuthenticationMode};
427: delete($ActiveTransactions{$Socket}); # Server has no transaction
428:
429: &Debug(5, "Server to idle");
430:
431: # If there's work to do, start the transaction:
432:
433: my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
434: if ($reqdata ne undef) {
435: Debug(5, "Queue gave request data: ".$reqdata->getRequest());
436: &StartRequest($Socket, $reqdata);
437:
438: } else {
439:
440: # There's no work waiting, so push the server to idle list.
441: &Debug(5, "No new work requests, server connection going idle");
442: $IdleConnections->push($Socket);
443: }
444: }
445:
446: =pod
447:
448: =head2 ClientWritable
449:
450: Event callback for when a client socket is writable.
451:
452: This callback is established when a transaction reponse is
453: avaiable from lond. The response is forwarded to the unix socket
454: as it becomes writable in this sub.
455:
456: Parameters:
457:
458: =item Event
459:
460: The event that has been triggered. Event->w->data is
461: the data and Event->w->fd is the socket to write.
462:
463: =cut
464:
465: sub ClientWritable {
466: my $Event = shift;
467: my $Watcher = $Event->w;
468: my $Data = $Watcher->data;
469: my $Socket = $Watcher->fd;
470:
471: # Try to send the data:
472:
473: &Debug(6, "ClientWritable writing".$Data);
474: &Debug(9, "Socket is: ".$Socket);
475:
476: if($Socket->connected) {
477: my $result = $Socket->send($Data, 0);
478:
479: # $result undefined: the write failed.
480: # otherwise $result is the number of bytes written.
481: # Remove that preceding string from the data.
482: # If the resulting data is empty, destroy the watcher
483: # and set up a read event handler to accept the next
484: # request.
485:
486: &Debug(9,"Send result is ".$result." Defined: ".defined($result));
487: if($result ne undef) {
488: &Debug(9, "send result was defined");
489: if($result == length($Data)) { # Entire string sent.
490: &Debug(9, "ClientWritable data all written");
491: $Watcher->cancel();
492: #
493: # Set up to read next request from socket:
494:
495: my $descr = sprintf("Connection to lonc client %d",
496: $ActiveClients{$Socket});
497: Event->io(cb => \&ClientRequest,
498: poll => 'r',
499: desc => $descr,
500: data => "",
501: fd => $Socket);
502:
503: } else { # Partial string sent.
504: $Watcher->data(substr($Data, $result));
505: if($result == 0) { # client hung up on us!!
506: # Log("INFO", "lonc pipe client hung up on us!");
507: $Watcher->cancel;
508: $Socket->shutdown(2);
509: $Socket->close();
510: }
511: }
512:
513: } else { # Error of some sort...
514:
515: # Some errnos are possible:
516: my $errno = $!;
517: if($errno == POSIX::EWOULDBLOCK ||
518: $errno == POSIX::EAGAIN ||
519: $errno == POSIX::EINTR) {
520: # No action taken?
521: } else { # Unanticipated errno.
522: &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
523: $Watcher->cancel; # Stop the watcher.
524: $Socket->shutdown(2); # Kill connection
525: $Socket->close(); # Close the socket.
526: }
527:
528: }
529: } else {
530: $Watcher->cancel(); # A delayed request...just cancel.
531: }
532: }
533:
534: =pod
535:
536: =head2 CompleteTransaction
537:
538: Called when the reply data has been received for a lond
539: transaction. The reply data must now be sent to the
540: ultimate client on the other end of the Unix socket. This is
541: done by setting up a writable event for the socket with the
542: data the reply data.
543:
544: Parameters:
545:
546: =item Socket
547:
548: Socket on which the lond transaction occured. This is a
549: LondConnection. The data received is in the TransactionReply member.
550:
551: =item Transaction
552:
553: The transaction that is being completed.
554:
555: =cut
556:
557: sub CompleteTransaction {
558: &Debug(5,"Complete transaction");
559:
560: my ($Socket, $Transaction) = @_;
561:
562: if (!$Transaction->isDeferred()) { # Normal transaction
563: my $data = $Socket->GetReply(); # Data to send.
564: if($LogTransactions) {
565: Log("SUCCESS", "Reply from lond: '$data'");
566: }
567: StartClientReply($Transaction, $data);
568: } else { # Delete deferred transaction file.
569: Log("SUCCESS", "A delayed transaction was completed");
570: LogPerm("S:$Transaction->getClient() :".$Transaction->getRequest());
571: unlink $Transaction->getFile();
572: }
573: }
574:
575: =pod
576:
577: =head1 StartClientReply
578:
579: Initiates a reply to a client where the reply data is a parameter.
580:
581: =head2 parameters:
582:
583: =item Transaction
584:
585: The transaction for which we are responding to the client.
586:
587: =item data
588:
589: The data to send to apached client.
590:
591: =cut
592:
593: sub StartClientReply {
594:
595: my ($Transaction, $data) = @_;
596:
597: my $Client = $Transaction->getClient();
598:
599: &Debug(8," Reply was: ".$data);
600: my $Serial = $ActiveClients{$Client};
601: my $desc = sprintf("Connection to lonc client %d",
602: $Serial);
603: Event->io(fd => $Client,
604: poll => "w",
605: desc => $desc,
606: cb => \&ClientWritable,
607: data => $data);
608: }
609:
610: =pod
611:
612: =head2 FailTransaction
613:
614: Finishes a transaction with failure because the associated lond socket
615: disconnected. There are two possibilities:
616: - The transaction is deferred: in which case we just quietly
617: delete the transaction since there is no client connection.
618: - The transaction is 'live' in which case we initiate the sending
619: of "con_lost" to the client.
620:
621: Deleting the transaction means killing it from the %ActiveTransactions hash.
622:
623: Parameters:
624:
625: =item client
626:
627: The LondTransaction we are failing.
628:
629:
630: =cut
631:
632: sub FailTransaction {
633: my $transaction = shift;
634:
635: # If the socket is dead, that's already logged.
636:
637: if ($ConnectionRetriesLeft > 0) {
638: Log("WARNING", "Failing transaction "
639: .$transaction->getRequest());
640: }
641: Debug(1, "Failing transaction: ".$transaction->getRequest());
642: if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
643: my $client = $transaction->getClient();
644: Debug(1," Replying con_lost to ".$transaction->getRequest());
645: StartClientReply($transaction, "con_lost\n");
646: }
647:
648: }
649:
650: =pod
651: =head1 EmptyQueue
652:
653: Fails all items in the work queue with con_lost.
654: Note that each item in the work queue is a transaction.
655:
656: =cut
657: sub EmptyQueue {
658: $ConnectionRetriesLeft--; # Counts as connection failure too.
659: while($WorkQueue->Count()) {
660: my $request = $WorkQueue->dequeue(); # This is a transaction
661: FailTransaction($request);
662: }
663: }
664:
665: =pod
666:
667: =head2 CloseAllLondConnections
668:
669: Close all connections open on lond prior to exit e.g.
670:
671: =cut
672: sub CloseAllLondConnections {
673: foreach my $Socket (keys %ActiveConnections) {
674: if(exists($ActiveTransactions{$Socket})) {
675: FailTransaction($ActiveTransactions{$Socket});
676: }
677: KillSocket($Socket);
678: }
679: }
680: =cut
681:
682: =pod
683:
684: =head2 KillSocket
685:
686: Destroys a socket. This function can be called either when a socket
687: has died of 'natural' causes or because a socket needs to be pruned due to
688: idleness. If the socket has died naturally, if there are no longer any
689: live connections a new connection is created (in case there are transactions
690: in the queue). If the socket has been pruned, it is never re-created.
691:
692: Parameters:
693:
694: =item Socket
695:
696: The socket to kill off.
697:
698: =item Restart
699:
700: nonzero if we are allowed to create a new connection.
701:
702:
703: =cut
704: sub KillSocket {
705: my $Socket = shift;
706:
707: Log("WARNING", "Shutting down a socket");
708: $Socket->Shutdown();
709:
710: # If the socket came from the active connection set,
711: # delete its transaction... note that FailTransaction should
712: # already have been called!!!
713: # otherwise it came from the idle set.
714: #
715:
716: if(exists($ActiveTransactions{$Socket})) {
717: delete ($ActiveTransactions{$Socket});
718: }
719: if(exists($ActiveConnections{$Socket})) {
720: delete($ActiveConnections{$Socket});
721: $ConnectionCount--;
722: if ($ConnectionCount < 0) { $ConnectionCount = 0; }
723: }
724: # If the connection count has gone to zero and there is work in the
725: # work queue, the work all gets failed with con_lost.
726: #
727: if($ConnectionCount == 0) {
728: EmptyQueue();
729: CloseAllLondConnections; # Should all already be closed but...
730: }
731: }
732:
733: =pod
734:
735: =head2 LondReadable
736:
737: This function is called whenever a lond connection
738: is readable. The action is state dependent:
739:
740: =head3 State=Initialized
741:
742: We''re waiting for the challenge, this is a no-op until the
743: state changes.
744:
745: =head3 State=Challenged
746:
747: The challenge has arrived we need to transition to Writable.
748: The connection must echo the challenge back.
749:
750: =head3 State=ChallengeReplied
751:
752: The challenge has been replied to. The we are receiveing the
753: 'ok' from the partner.
754:
755: =head3 State=ReadingVersionString
756:
757: We have requested the lond version and are reading the
758: version back. Upon completion, we'll store the version away
759: for future use(?).
760:
761: =head3 State=HostSet
762:
763: We have selected the domain name of our peer (multhomed hosts)
764: and are getting the reply (presumably ok) back.
765:
766: =head3 State=RequestingKey
767:
768: The ok has been received and we need to send the request for
769: an encryption key. Transition to writable for that.
770:
771: =head3 State=ReceivingKey
772:
773: The the key has been requested, now we are reading the new key.
774:
775: =head3 State=Idle
776:
777: The encryption key has been negotiated or we have finished
778: reading data from the a transaction. If the callback data has
779: a client as well as the socket iformation, then we are
780: doing a transaction and the data received is relayed to the client
781: before the socket is put on the idle list.
782:
783: =head3 State=SendingRequest
784:
785: I do not think this state can be received here, but if it is,
786: the appropriate thing to do is to transition to writable, and send
787: the request.
788:
789: =head3 State=ReceivingReply
790:
791: We finished sending the request to the server and now transition
792: to readable to receive the reply.
793:
794: The parameter to this function are:
795:
796: The event. Implicit in this is the watcher and its data. The data
797: contains at least the lond connection object and, if a
798: transaction is in progress, the socket attached to the local client.
799:
800: =cut
801:
802: sub LondReadable {
803:
804: my $Event = shift;
805: my $Watcher = $Event->w;
806: my $Socket = $Watcher->data;
807: my $client = undef;
808:
809: &Debug(6,"LondReadable called state = ".$Socket->GetState());
810:
811:
812: my $State = $Socket->GetState(); # All action depends on the state.
813:
814: SocketDump(6, $Socket);
815: my $status = $Socket->Readable();
816:
817: &Debug(2, "Socket->Readable returned: $status");
818:
819: if($status != 0) {
820: # bad return from socket read. Currently this means that
821: # The socket has become disconnected. We fail the transaction.
822:
823: Log("WARNING",
824: "Lond connection lost.");
825: if(exists($ActiveTransactions{$Socket})) {
826: FailTransaction($ActiveTransactions{$Socket});
827: } else {
828: # Socket is connecting and failed... need to mark
829: # no longer connecting.
830:
831: $LondConnecting = 0;
832: }
833: $Watcher->cancel();
834: KillSocket($Socket);
835: $ConnectionRetriesLeft--; # Counts as connection failure
836: return;
837: }
838: SocketDump(6,$Socket);
839:
840: $State = $Socket->GetState(); # Update in case of transition.
841: &Debug(6, "After read, state is ".$State);
842:
843: if($State eq "Initialized") {
844:
845:
846: } elsif ($State eq "ChallengeReceived") {
847: # The challenge must be echoed back; The state machine
848: # in the connection takes care of setting that up. Just
849: # need to transition to writable:
850:
851: $Watcher->cb(\&LondWritable);
852: $Watcher->poll("w");
853:
854: } elsif ($State eq "ChallengeReplied") {
855:
856: } elsif ($State eq "RequestingVersion") {
857: # Need to ask for the version... that is writiability:
858:
859: $Watcher->cb(\&LondWritable);
860: $Watcher->poll("w");
861:
862: } elsif ($State eq "ReadingVersionString") {
863: # Read the rest of the version string...
864: } elsif ($State eq "SetHost") {
865: # Need to request the actual domain get set...
866:
867: $Watcher->cb(\&LondWritable);
868: $Watcher->poll("w");
869: } elsif ($State eq "HostSet") {
870: # Reading the 'ok' from the peer.
871:
872: } elsif ($State eq "RequestingKey") {
873: # The ok was received. Now we need to request the key
874: # That requires us to be writable:
875:
876: $Watcher->cb(\&LondWritable);
877: $Watcher->poll("w");
878:
879: } elsif ($State eq "ReceivingKey") {
880:
881: } elsif ($State eq "Idle") {
882:
883: # This is as good a spot as any to get the peer version
884: # string:
885:
886: if($LondVersion eq "unknown") {
887: $LondVersion = $Socket->PeerVersion();
888: Log("INFO", "Connected to lond version: $LondVersion");
889: }
890: # If necessary, complete a transaction and then go into the
891: # idle queue.
892: # Note that a trasition to idle indicates a live lond
893: # on the other end so reset the connection retries.
894: #
895: $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
896: $Watcher->cancel();
897: if(exists($ActiveTransactions{$Socket})) {
898: Debug(5,"Completing transaction!!");
899: CompleteTransaction($Socket,
900: $ActiveTransactions{$Socket});
901: } else {
902: Log("SUCCESS", "Connection ".$ConnectionCount." to "
903: .$RemoteHost." now ready for action");
904: }
905: ServerToIdle($Socket); # Next work unit or idle.
906:
907: #
908: $LondConnecting = 0; # Best spot I can think of for this.
909: #
910:
911: } elsif ($State eq "SendingRequest") {
912: # We need to be writable for this and probably don't belong
913: # here inthe first place.
914:
915: Deubg(6, "SendingRequest state encountered in readable");
916: $Watcher->poll("w");
917: $Watcher->cb(\&LondWritable);
918:
919: } elsif ($State eq "ReceivingReply") {
920:
921:
922: } else {
923: # Invalid state.
924: Debug(4, "Invalid state in LondReadable");
925: }
926: }
927:
928: =pod
929:
930: =head2 LondWritable
931:
932: This function is called whenever a lond connection
933: becomes writable while there is a writeable monitoring
934: event. The action taken is very state dependent:
935:
936: =head3 State = Connected
937:
938: The connection is in the process of sending the 'init' hailing to the
939: lond on the remote end. The connection object''s Writable member is
940: called. On error, ConnectionError is called to destroy the connection
941: and remove it from the ActiveConnections hash
942:
943: =head3 Initialized
944:
945: 'init' has been sent, writability monitoring is removed and
946: readability monitoring is started with LondReadable as the callback.
947:
948: =head3 ChallengeReceived
949:
950: The connection has received the who are you challenge from the remote
951: system, and is in the process of sending the challenge
952: response. Writable is called.
953:
954: =head3 ChallengeReplied
955:
956: The connection has replied to the initial challenge The we switch to
957: monitoring readability looking for the server to reply with 'ok'.
958:
959: =head3 RequestingKey
960:
961: The connection is in the process of requesting its encryption key.
962: Writable is called.
963:
964: =head3 ReceivingKey
965:
966: The connection has sent the request for a key. Switch to readability
967: monitoring to accept the key
968:
969: =head3 SendingRequest
970:
971: The connection is in the process of sending a request to the server.
972: This request is part of a client transaction. All the states until
973: now represent the client setup protocol. Writable is called.
974:
975: =head3 ReceivingReply
976:
977: The connection has sent a request. Now it must receive a reply.
978: Readability monitoring is requested.
979:
980: This function is an event handler and therefore receives as
981: a parameter the event that has fired. The data for the watcher
982: of this event is a reference to a list of one or two elements,
983: depending on state. The first (and possibly only) element is the
984: socket. The second (present only if a request is in progress)
985: is the socket on which to return a reply to the caller.
986:
987: =cut
988:
989: sub LondWritable {
990: my $Event = shift;
991: my $Watcher = $Event->w;
992: my $Socket = $Watcher->data;
993: my $State = $Socket->GetState();
994:
995: Debug(6,"LondWritable State = ".$State."\n");
996:
997:
998: # Figure out what to do depending on the state of the socket:
999:
1000:
1001:
1002:
1003: SocketDump(6,$Socket);
1004:
1005: # If the socket is writable, we must always write.
1006: # Only by writing will we undergo state transitions.
1007: # Old logic wrote in state specific code below, however
1008: # That forces us at least through another invocation of
1009: # this function after writability is possible again.
1010: # This logic also factors out common code for handling
1011: # write failures... in all cases, write failures
1012: # Kill the socket.
1013: # This logic makes the branches of the >big< if below
1014: # so that the writing states are actually NO-OPs.
1015:
1016: if ($Socket->Writable() != 0) {
1017: # The write resulted in an error.
1018: # We'll treat this as if the socket got disconnected:
1019: Log("WARNING", "Connection to ".$RemoteHost.
1020: " has been disconnected");
1021: if(exists($ActiveTransactions{$Socket})) {
1022: FailTransaction($ActiveTransactions{$Socket});
1023: } else {
1024: # In the process of conneting, so need to turn that off.
1025:
1026: $LondConnecting = 0;
1027: }
1028: $Watcher->cancel();
1029: KillSocket($Socket);
1030: return;
1031: }
1032:
1033:
1034:
1035: if ($State eq "Connected") {
1036:
1037: # "init" is being sent...
1038:
1039: } elsif ($State eq "Initialized") {
1040:
1041: # Now that init was sent, we switch
1042: # to watching for readability:
1043:
1044: $Watcher->cb(\&LondReadable);
1045: $Watcher->poll("r");
1046:
1047: } elsif ($State eq "ChallengeReceived") {
1048: # We received the challenge, now we
1049: # are echoing it back. This is a no-op,
1050: # we're waiting for the state to change
1051:
1052: } elsif ($State eq "ChallengeReplied") {
1053: # The echo was sent back, so we switch
1054: # to watching readability.
1055:
1056: $Watcher->cb(\&LondReadable);
1057: $Watcher->poll("r");
1058: } elsif ($State eq "RequestingVersion") {
1059: # Sending the peer a version request...
1060:
1061: } elsif ($State eq "ReadingVersionString") {
1062: # Transition to read since we have sent the
1063: # version command and now just need to read the
1064: # version string from the peer:
1065:
1066: $Watcher->cb(\&LondReadable);
1067: $Watcher->poll("r");
1068:
1069: } elsif ($State eq "SetHost") {
1070: # Setting the remote domain...
1071:
1072: } elsif ($State eq "HostSet") {
1073: # Back to readable to get the ok.
1074:
1075: $Watcher->cb(\&LondReadable);
1076: $Watcher->poll("r");
1077:
1078:
1079: } elsif ($State eq "RequestingKey") {
1080: # At this time we're requesting the key.
1081: # again, this is essentially a no-op.
1082:
1083: } elsif ($State eq "ReceivingKey") {
1084: # Now we need to wait for the key
1085: # to come back from the peer:
1086:
1087: $Watcher->cb(\&LondReadable);
1088: $Watcher->poll("r");
1089:
1090: } elsif ($State eq "SendingRequest") {
1091:
1092: # At this time we are sending a request to the
1093: # peer... write the next chunk:
1094:
1095:
1096: } elsif ($State eq "ReceivingReply") {
1097: # The send has completed. Wait for the
1098: # data to come in for a reply.
1099: Debug(8,"Writable sent request/receiving reply");
1100: $Watcher->cb(\&LondReadable);
1101: $Watcher->poll("r");
1102:
1103: } else {
1104: # Control only passes here on an error:
1105: # the socket state does not match any
1106: # of the known states... so an error
1107: # must be logged.
1108:
1109: &Debug(4, "Invalid socket state ".$State."\n");
1110: }
1111:
1112: }
1113: =pod
1114:
1115: =cut
1116: sub QueueDelayed {
1117: Debug(3,"QueueDelayed called");
1118:
1119: my $path = "$perlvar{'lonSockDir'}/delayed";
1120:
1121: Debug(4, "Delayed path: ".$path);
1122: opendir(DIRHANDLE, $path);
1123:
1124: my @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
1125: closedir(DIRHANDLE);
1126: my $dfname;
1127: my $reqfile;
1128: foreach $dfname (sort @alldelayed) {
1129: $reqfile = "$path/$dfname";
1130: Debug(4, "queueing ".$reqfile);
1131: my $Handle = IO::File->new($reqfile);
1132: my $cmd = <$Handle>;
1133: chomp $cmd; # There may or may not be a newline...
1134: $cmd = $cmd."\n"; # now for sure there's exactly one newline.
1135: my $Transaction = LondTransaction->new($cmd);
1136: $Transaction->SetDeferred($reqfile);
1137: QueueTransaction($Transaction);
1138: }
1139:
1140: }
1141:
1142: =pod
1143:
1144: =head2 MakeLondConnection
1145:
1146: Create a new lond connection object, and start it towards its initial
1147: idleness. Once idle, it becomes elligible to receive transactions
1148: from the work queue. If the work queue is not empty when the
1149: connection is completed and becomes idle, it will dequeue an entry and
1150: start off on it.
1151:
1152: =cut
1153:
1154: sub MakeLondConnection {
1155: Debug(4,"MakeLondConnection to ".GetServerHost()." on port "
1156: .GetServerPort());
1157:
1158: my $Connection = LondConnection->new(&GetServerHost(),
1159: &GetServerPort());
1160:
1161: if($Connection eq undef) { # Needs to be more robust later.
1162: Log("CRITICAL","Failed to make a connection with lond.");
1163: $ConnectionRetriesLeft--;
1164: return 0; # Failure.
1165: } else {
1166:
1167: # The connection needs to have writability
1168: # monitored in order to send the init sequence
1169: # that starts the whole authentication/key
1170: # exchange underway.
1171: #
1172: my $Socket = $Connection->GetSocket();
1173: if($Socket eq undef) {
1174: die "did not get a socket from the connection";
1175: } else {
1176: &Debug(9,"MakeLondConnection got socket: ".$Socket);
1177: }
1178:
1179: $Connection->SetTimeoutCallback(\&SocketTimeout);
1180:
1181: my $event = Event->io(fd => $Socket,
1182: poll => 'w',
1183: cb => \&LondWritable,
1184: data => $Connection,
1185: desc => 'Connection to lond server');
1186: $ActiveConnections{$Connection} = $event;
1187: if ($ConnectionCount == 0) {
1188: &SetupTimer; # Need to handle timeouts with connections...
1189: }
1190: $ConnectionCount++;
1191: Debug(4, "Connection count = ".$ConnectionCount);
1192: if($ConnectionCount == 1) { # First Connection:
1193: QueueDelayed;
1194: }
1195: Log("SUCESS", "Created connection ".$ConnectionCount
1196: ." to host ".GetServerHost());
1197: $LondConnecting = 1; # Connection in progress.
1198: return 1; # Return success.
1199: }
1200:
1201: }
1202:
1203: =pod
1204:
1205: =head2 StartRequest
1206:
1207: Starts a lond request going on a specified lond connection.
1208: parameters are:
1209:
1210: =item $Lond
1211:
1212: Connection to the lond that will send the transaction and receive the
1213: reply.
1214:
1215: =item $Client
1216:
1217: Connection to the client that is making this request We got the
1218: request from this socket, and when the request has been relayed to
1219: lond and we get a reply back from lond it will get sent to this
1220: socket.
1221:
1222: =item $Request
1223:
1224: The text of the request to send.
1225:
1226: =cut
1227:
1228: sub StartRequest {
1229:
1230: my ($Lond, $Request) = @_;
1231:
1232: Debug(6, "StartRequest: ".$Request->getRequest());
1233:
1234: my $Socket = $Lond->GetSocket();
1235:
1236: $Request->Activate($Lond);
1237: $ActiveTransactions{$Lond} = $Request;
1238:
1239: $Lond->InitiateTransaction($Request->getRequest());
1240: my $event = Event->io(fd => $Socket,
1241: poll => "w",
1242: cb => \&LondWritable,
1243: data => $Lond,
1244: desc => "lond transaction connection");
1245: $ActiveConnections{$Lond} = $event;
1246: Debug(8," Start Request made watcher data with ".$event->data."\n");
1247: }
1248:
1249: =pod
1250:
1251: =head2 QueueTransaction
1252:
1253: If there is an idle lond connection, it is put to work doing this
1254: transaction. Otherwise, the transaction is placed in the work queue.
1255: If placed in the work queue and the maximum number of connections has
1256: not yet been created, a new connection will be started. Our goal is
1257: to eventually have a sufficient number of connections that the work
1258: queue will typically be empty. parameters are:
1259:
1260: =item Socket
1261:
1262: open on the lonc client.
1263:
1264: =item Request
1265:
1266: data to send to the lond.
1267:
1268: =cut
1269:
1270: sub QueueTransaction {
1271:
1272: my $requestData = shift; # This is a LondTransaction.
1273: my $cmd = $requestData->getRequest();
1274:
1275: Debug(6,"QueueTransaction: ".$cmd);
1276:
1277: my $LondSocket = $IdleConnections->pop();
1278: if(!defined $LondSocket) { # Need to queue request.
1279: Debug(5,"Must queue...");
1280: $WorkQueue->enqueue($requestData);
1281: Debug(5, "Queue Transaction startnew $ConnectionCount $LondConnecting");
1282: if(($ConnectionCount < $MaxConnectionCount) && (! $LondConnecting)) {
1283:
1284: if($ConnectionRetriesLeft > 0) {
1285: Debug(5,"Starting additional lond connection");
1286: if(&MakeLondConnection() == 0) {
1287: EmptyQueue(); # Fail transactions, can't make connection.
1288: CloseAllLondConnections; # Should all be closed but...
1289: }
1290: } else {
1291: ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
1292: $LondConnecting = 0;
1293: EmptyQueue(); # It's worse than that ... he's dead Jim.
1294: CloseAllLondConnections; # Should all be closed but..
1295: }
1296: }
1297: } else { # Can start the request:
1298: Debug(8,"Can start...");
1299: StartRequest($LondSocket, $requestData);
1300: }
1301: }
1302:
1303: #-------------------------- Lonc UNIX socket handling ---------------------
1304:
1305: =pod
1306:
1307: =head2 ClientRequest
1308: Callback that is called when data can be read from the UNIX domain
1309: socket connecting us with an apache server process.
1310:
1311: =cut
1312:
1313: sub ClientRequest {
1314: Debug(6, "ClientRequest");
1315: my $event = shift;
1316: my $watcher = $event->w;
1317: my $socket = $watcher->fd;
1318: my $data = $watcher->data;
1319: my $thisread;
1320:
1321: Debug(9, " Watcher named: ".$watcher->desc);
1322:
1323: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1324: Debug(8, "rcv: data length = ".length($thisread)
1325: ." read =".$thisread);
1326: unless (defined $rv && length($thisread)) {
1327: # Likely eof on socket.
1328: Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
1329: close($socket);
1330: $watcher->cancel();
1331: delete($ActiveClients{$socket});
1332: return;
1333: }
1334: Debug(8,"Data: ".$data." this read: ".$thisread);
1335: $data = $data.$thisread; # Append new data.
1336: $watcher->data($data);
1337: if($data =~ /\n$/) { # Request entirely read.
1338: if($data eq "close_connection_exit\n") {
1339: Log("CRITICAL",
1340: "Request Close Connection ... exiting");
1341: CloseAllLondConnections();
1342: exit;
1343: }
1344: Debug(8, "Complete transaction received: ".$data);
1345: if($LogTransactions) {
1346: Log("SUCCESS", "Transaction: '$data'"); # Transaction has \n.
1347: }
1348: my $Transaction = LondTransaction->new($data);
1349: $Transaction->SetClient($socket);
1350: QueueTransaction($Transaction);
1351: $watcher->cancel(); # Done looking for input data.
1352: }
1353:
1354: }
1355:
1356:
1357: =pod
1358:
1359: =head2 NewClient
1360:
1361: Callback that is called when a connection is received on the unix
1362: socket for a new client of lonc. The callback is parameterized by the
1363: event.. which is a-priori assumed to be an io event, and therefore has
1364: an fd member that is the Listener socket. We Accept the connection
1365: and register a new event on the readability of that socket:
1366:
1367: =cut
1368:
1369: sub NewClient {
1370: Debug(6, "NewClient");
1371: my $event = shift; # Get the event parameters.
1372: my $watcher = $event->w;
1373: my $socket = $watcher->fd; # Get the event' socket.
1374: my $connection = $socket->accept(); # Accept the client connection.
1375: Debug(8,"Connection request accepted from "
1376: .GetPeername($connection, AF_UNIX));
1377:
1378:
1379: my $description = sprintf("Connection to lonc client %d",
1380: $ClientConnection);
1381: Debug(9, "Creating event named: ".$description);
1382: Event->io(cb => \&ClientRequest,
1383: poll => 'r',
1384: desc => $description,
1385: data => "",
1386: fd => $connection);
1387: $ActiveClients{$connection} = $ClientConnection;
1388: $ClientConnection++;
1389: }
1390:
1391: =pod
1392:
1393: =head2 GetLoncSocketPath
1394:
1395: Returns the name of the UNIX socket on which to listen for client
1396: connections.
1397:
1398: =head2 Parameters:
1399:
1400: host (optional) - Name of the host socket to return.. defaults to
1401: the return from GetServerHost().
1402:
1403: =cut
1404:
1405: sub GetLoncSocketPath {
1406:
1407: my $host = GetServerHost(); # Default host.
1408: if (@_) {
1409: ($host) = @_; # Override if supplied.
1410: }
1411: return $UnixSocketDir."/".$host;
1412: }
1413:
1414: =pod
1415:
1416: =head2 GetServerHost
1417:
1418: Returns the host whose lond we talk with.
1419:
1420: =cut
1421:
1422: sub GetServerHost {
1423: return $RemoteHost; # Setup by the fork.
1424: }
1425:
1426: =pod
1427:
1428: =head2 GetServerPort
1429:
1430: Returns the lond port number.
1431:
1432: =cut
1433:
1434: sub GetServerPort {
1435: return $perlvar{londPort};
1436: }
1437:
1438: =pod
1439:
1440: =head2 SetupLoncListener
1441:
1442: Setup a lonc listener event. The event is called when the socket
1443: becomes readable.. that corresponds to the receipt of a new
1444: connection. The event handler established will accept the connection
1445: (creating a communcations channel), that int turn will establish
1446: another event handler to subess requests.
1447:
1448: =head2 Parameters:
1449:
1450: host (optional) Name of the host to set up a unix socket to.
1451:
1452: =cut
1453:
1454: sub SetupLoncListener {
1455:
1456: my $host = GetServerHost(); # Default host.
1457: if (@_) {
1458: ($host) = @_ # Override host with parameter.
1459: }
1460:
1461: my $socket;
1462: my $SocketName = GetLoncSocketPath($host);
1463: unlink($SocketName);
1464: unless ($socket =IO::Socket::UNIX->new(Local => $SocketName,
1465: Listen => 250,
1466: Type => SOCK_STREAM)) {
1467: die "Failed to create a lonc listner socket";
1468: }
1469: Event->io(cb => \&NewClient,
1470: poll => 'r',
1471: desc => 'Lonc listener Unix Socket',
1472: fd => $socket);
1473: }
1474:
1475: #
1476: # Toggle transaction logging.
1477: # Implicit inputs:
1478: # LogTransactions
1479: # Implicit Outputs:
1480: # LogTransactions
1481: sub ToggleTransactionLogging {
1482: print STDERR "Toggle transaction logging...\n";
1483: if(!$LogTransactions) {
1484: $LogTransactions = 1;
1485: } else {
1486: $LogTransactions = 0;
1487: }
1488:
1489:
1490: Log("SUCCESS", "Toggled transaction logging: $LogTransactions \n");
1491: }
1492:
1493: =pod
1494:
1495: =head2 ChildStatus
1496:
1497: Child USR1 signal handler to report the most recent status
1498: into the status file.
1499:
1500: We also use this to reset the retries count in order to allow the
1501: client to retry connections with a previously dead server.
1502: =cut
1503:
1504: sub ChildStatus {
1505: my $event = shift;
1506: my $watcher = $event->w;
1507:
1508: Debug(2, "Reporting child status because : ".$watcher->data);
1509: my $docdir = $perlvar{'lonDocRoot'};
1510: my $fh = IO::File->new(">>$docdir/lon-status/loncstatus.txt");
1511: print $fh $$."\t".$RemoteHost."\t".$Status."\t".
1512: $RecentLogEntry."\n";
1513: #
1514: # Write out information about each of the connections:
1515: #
1516: if ($DebugLevel > 2) {
1517: print $fh "Active connection statuses: \n";
1518: my $i = 1;
1519: print STDERR "================================= Socket Status Dump:\n";
1520: foreach my $item (keys %ActiveConnections) {
1521: my $Socket = $ActiveConnections{$item}->data;
1522: my $state = $Socket->GetState();
1523: print $fh "Connection $i State: $state\n";
1524: print STDERR "---------------------- Connection $i \n";
1525: $Socket->Dump(-1); # Ensure it gets dumped..
1526: $i++;
1527: }
1528: }
1529: $ConnectionRetriesLeft = $ConnectionRetries;
1530: }
1531:
1532: =pod
1533:
1534: =head2 SignalledToDeath
1535:
1536: Called in response to a signal that causes a chid process to die.
1537:
1538: =cut
1539:
1540:
1541: sub SignalledToDeath {
1542: my $event = shift;
1543: my $watcher= $event->w;
1544:
1545: Debug(2,"Signalled to death! via ".$watcher->data);
1546: my ($signal) = $watcher->data;
1547: chomp($signal);
1548: Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "
1549: ."died through "."\"$signal\"");
1550: LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
1551: ."\"$signal\"");
1552: exit 0;
1553:
1554: }
1555:
1556: =head2 ToggleDebug
1557:
1558: This sub toggles trace debugging on and off.
1559:
1560: =cut
1561:
1562: sub ToggleDebug {
1563: my $Current = $DebugLevel;
1564: $DebugLevel = $NextDebugLevel;
1565: $NextDebugLevel = $Current;
1566:
1567: Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
1568:
1569: }
1570:
1571: =head2 ChildProcess
1572:
1573: This sub implements a child process for a single lonc daemon.
1574:
1575: =cut
1576:
1577: sub ChildProcess {
1578:
1579:
1580: #
1581: # Signals must be handled by the Event framework...
1582: #
1583:
1584: Event->signal(signal => "QUIT",
1585: cb => \&SignalledToDeath,
1586: data => "QUIT");
1587: Event->signal(signal => "HUP",
1588: cb => \&ChildStatus,
1589: data => "HUP");
1590: Event->signal(signal => "USR1",
1591: cb => \&ChildStatus,
1592: data => "USR1");
1593: Event->signal(signal => "USR2",
1594: cb => \&ToggleTransactionLogging);
1595: Event->signal(signal => "INT",
1596: cb => \&ToggleDebug,
1597: data => "INT");
1598:
1599:
1600: SetupLoncListener();
1601:
1602: $Event::Debuglevel = $DebugLevel;
1603:
1604: Debug(9, "Making initial lond connection for ".$RemoteHost);
1605:
1606: # Setup the initial server connection:
1607:
1608: # &MakeLondConnection(); // let first work requirest do it.
1609:
1610:
1611: Debug(9,"Entering event loop");
1612: my $ret = Event::loop(); # Start the main event loop.
1613:
1614:
1615: die "Main event loop exited!!!";
1616: }
1617:
1618: # Create a new child for host passed in:
1619:
1620: sub CreateChild {
1621: my $host = shift;
1622:
1623: my $sigset = POSIX::SigSet->new(SIGINT);
1624: sigprocmask(SIG_BLOCK, $sigset);
1625: $RemoteHost = $host;
1626: Log("CRITICAL", "Forking server for ".$host);
1627: my $pid = fork;
1628: if($pid) { # Parent
1629: $RemoteHost = "Parent";
1630: $ChildHash{$pid} = $host;
1631: $HostToPid{$host}= $pid;
1632: sigprocmask(SIG_UNBLOCK, $sigset);
1633:
1634: } else { # child.
1635: ShowStatus("Connected to ".$RemoteHost);
1636: $SIG{INT} = 'DEFAULT';
1637: sigprocmask(SIG_UNBLOCK, $sigset);
1638: ChildProcess; # Does not return.
1639: }
1640:
1641: }
1642: #
1643: # Parent process logic pass 1:
1644: # For each entry in the hosts table, we will
1645: # fork off an instance of ChildProcess to service the transactions
1646: # to that host. Each pid will be entered in a global hash
1647: # with the value of the key, the host.
1648: # The parent will then enter a loop to wait for process exits.
1649: # Each exit gets logged and the child gets restarted.
1650: #
1651:
1652: #
1653: # Fork and start in new session so hang-up isn't going to
1654: # happen without intent.
1655: #
1656:
1657:
1658:
1659:
1660:
1661:
1662: ShowStatus("Forming new session");
1663: my $childpid = fork;
1664: if ($childpid != 0) {
1665: sleep 4; # Give child a chacne to break to
1666: exit 0; # a new sesion.
1667: }
1668: #
1669: # Write my pid into the pid file so I can be located
1670: #
1671:
1672: ShowStatus("Parent writing pid file:");
1673: my $execdir = $perlvar{'lonDaemons'};
1674: open (PIDSAVE, ">$execdir/logs/lonc.pid");
1675: print PIDSAVE "$$\n";
1676: close(PIDSAVE);
1677:
1678:
1679:
1680: if (POSIX::setsid() < 0) {
1681: print "Could not create new session\n";
1682: exit -1;
1683: }
1684:
1685: ShowStatus("Forking node servers");
1686:
1687: Log("CRITICAL", "--------------- Starting children ---------------");
1688:
1689: LondConnection::ReadConfig; # Read standard config files.
1690: my $HostIterator = LondConnection::GetHostIterator;
1691: while (! $HostIterator->end()) {
1692:
1693: my $hostentryref = $HostIterator->get();
1694: CreateChild($hostentryref->[0]);
1695: $HostHash{$hostentryref->[0]} = $hostentryref->[4];
1696: $HostIterator->next();
1697: }
1698: $RemoteHost = "Parent Server";
1699:
1700: # Maintain the population:
1701:
1702: ShowStatus("Parent keeping the flock");
1703:
1704: #
1705: # Set up parent signals:
1706: #
1707:
1708: $SIG{INT} = \&Terminate;
1709: $SIG{TERM} = \&Terminate;
1710: $SIG{HUP} = \&Restart;
1711: $SIG{USR1} = \&CheckKids;
1712: $SIG{USR2} = \&UpdateKids; # LonManage update request.
1713:
1714: while(1) {
1715: my $deadchild = wait();
1716: if(exists $ChildHash{$deadchild}) { # need to restart.
1717: my $deadhost = $ChildHash{$deadchild};
1718: delete($HostToPid{$deadhost});
1719: delete($ChildHash{$deadchild});
1720: Log("WARNING","Lost child pid= ".$deadchild.
1721: "Connected to host ".$deadhost);
1722: Log("INFO", "Restarting child procesing ".$deadhost);
1723: CreateChild($deadhost);
1724: }
1725: }
1726:
1727:
1728:
1729: =pod
1730:
1731: =head1 CheckKids
1732:
1733: Since kids do not die as easily in this implementation
1734: as the previous one, there is no need to restart the
1735: dead ones (all dead kids get restarted when they die!!)
1736: The only thing this function does is to pass USR1 to the
1737: kids so that they report their status.
1738:
1739: =cut
1740:
1741: sub CheckKids {
1742: Debug(2, "Checking status of children");
1743: my $docdir = $perlvar{'lonDocRoot'};
1744: my $fh = IO::File->new(">$docdir/lon-status/loncstatus.txt");
1745: my $now=time;
1746: my $local=localtime($now);
1747: print $fh "LONC status $local - parent $$ \n\n";
1748: foreach my $pid (keys %ChildHash) {
1749: Debug(2, "Sending USR1 -> $pid");
1750: kill 'USR1' => $pid; # Tell Child to report status.
1751: sleep 1; # Wait so file doesn't intermix.
1752: }
1753: }
1754:
1755: =pod
1756:
1757: =head1 UpdateKids
1758:
1759: parent's SIGUSR2 handler. This handler:
1760:
1761: =item
1762:
1763: Rereads the hosts file.
1764:
1765: =item
1766:
1767: Kills off (via sigint) children for hosts that have disappeared.
1768:
1769: =item
1770:
1771: QUITs children for hosts that already exist (this just forces a status display
1772: and resets the connection retry count for that host.
1773:
1774: =item
1775:
1776: Starts new children for hosts that have been added to the hosts.tab file since
1777: the start of the master program and maintains them.
1778:
1779: =cut
1780:
1781: sub UpdateKids {
1782:
1783: Log("INFO", "Updating connections via SIGUSR2");
1784:
1785: # Just in case we need to kill our own lonc, we wait a few seconds to
1786: # give it a chance to receive and relay lond's response to the
1787: # re-init command.
1788: #
1789:
1790: sleep(2); # Wait a couple of seconds.
1791:
1792: my %hosts; # Indexed by loncapa hostname, value=ip.
1793:
1794: # Need to re-read the host table:
1795:
1796:
1797: LondConnection::ReadConfig();
1798: my $I = LondConnection::GetHostIterator;
1799: while (! $I->end()) {
1800: my $item = $I->get();
1801: $hosts{$item->[0]} = $item->[4];
1802: $I->next();
1803: }
1804:
1805: # The logic below is written for clarity not for efficiency.
1806: # Since I anticipate that this function is only rarely called, that's
1807: # appropriate. There are certainly ways to combine the loops below,
1808: # and anyone wishing to obscure the logic is welcome to go for it.
1809: # Note that we don't re-direct sigchild. Instead we do what's needed
1810: # to the data structures that keep track of children to ensure that
1811: # when sigchild is honored, no new child is born.
1812: #
1813:
1814: # For each existing child; if it's host doesn't exist, kill the child.
1815:
1816: foreach my $child (keys %ChildHash) {
1817: my $oldhost = $ChildHash{$child};
1818: if (!(exists $hosts{$oldhost})) {
1819: Log("CRITICAL", "Killing child for $oldhost host no longer exists");
1820: delete $ChildHash{$child};
1821: delete $HostToPid{$oldhost};
1822: kill 'QUIT' => $child;
1823: }
1824: }
1825: # For each remaining existing child; if it's host's ip has changed,
1826: # Restart the child on the new IP.
1827:
1828: foreach my $child (keys %ChildHash) {
1829: my $oldhost = $ChildHash{$child};
1830: my $oldip = $HostHash{$oldhost};
1831: if ($hosts{$oldhost} ne $oldip) {
1832:
1833: # kill the old child.
1834:
1835: Log("CRITICAL", "Killing child for $oldhost host ip has changed...");
1836: delete $ChildHash{$child};
1837: delete $HostToPid{$oldhost};
1838: kill 'QUIT' => $child;
1839:
1840: # Do the book-keeping needed to start a new child on the
1841: # new ip.
1842:
1843: $HostHash{$oldhost} = $hosts{$oldhost};
1844: CreateChild($oldhost);
1845: }
1846: }
1847: # Finally, for each new host, not in the host hash, create a
1848: # enter the host and create a new child.
1849: # Force a status display of any existing process.
1850:
1851: foreach my $host (keys %hosts) {
1852: if(!(exists $HostHash{$host})) {
1853: Log("INFO", "New host $host discovered in hosts.tab...");
1854: $HostHash{$host} = $hosts{$host};
1855: CreateChild($host);
1856: } else {
1857: kill 'HUP' => $HostToPid{$host}; # status display.
1858: }
1859: }
1860: }
1861:
1862:
1863: =pod
1864:
1865: =head1 Restart
1866:
1867: Signal handler for HUP... all children are killed and
1868: we self restart. This is an el-cheapo way to re read
1869: the config file.
1870:
1871: =cut
1872:
1873: sub Restart {
1874: &KillThemAll; # First kill all the children.
1875: Log("CRITICAL", "Restarting");
1876: my $execdir = $perlvar{'lonDaemons'};
1877: unlink("$execdir/logs/lonc.pid");
1878: exec("$execdir/loncnew");
1879: }
1880:
1881: =pod
1882:
1883: =head1 KillThemAll
1884:
1885: Signal handler that kills all children by sending them a
1886: SIGHUP. Responds to sigint and sigterm.
1887:
1888: =cut
1889:
1890: sub KillThemAll {
1891: Debug(2, "Kill them all!!");
1892: local($SIG{CHLD}) = 'IGNORE'; # Our children >will< die.
1893: foreach my $pid (keys %ChildHash) {
1894: my $serving = $ChildHash{$pid};
1895: ShowStatus("Nicely Killing lonc for $serving pid = $pid");
1896: Log("CRITICAL", "Nicely Killing lonc for $serving pid = $pid");
1897: kill 'QUIT' => $pid;
1898: }
1899:
1900:
1901: }
1902:
1903:
1904: #
1905: # Kill all children via KILL. Just in case the
1906: # first shot didn't get them.
1907:
1908: sub really_kill_them_all_dammit
1909: {
1910: Debug(2, "Kill them all Dammit");
1911: local($SIG{CHLD} = 'IGNORE'); # In case some purist reenabled them.
1912: foreach my $pid (keys %ChildHash) {
1913: my $serving = $ChildHash{$pid};
1914: &ShowStatus("Nastily killing lonc for $serving pid = $pid");
1915: Log("CRITICAL", "Nastily killing lonc for $serving pid = $pid");
1916: kill 'KILL' => $pid;
1917: delete($ChildHash{$pid});
1918: my $execdir = $perlvar{'lonDaemons'};
1919: unlink("$execdir/logs/lonc.pid");
1920: }
1921: }
1922: =pod
1923:
1924: =head1 Terminate
1925:
1926: Terminate the system.
1927:
1928: =cut
1929:
1930: sub Terminate {
1931: &Log("CRITICAL", "Asked to kill children.. first be nice...");
1932: &KillThemAll;
1933: #
1934: # By now they really should all be dead.. but just in case
1935: # send them all SIGKILL's after a bit of waiting:
1936:
1937: sleep(4);
1938: &Log("CRITICAL", "Now kill children nasty");
1939: &really_kill_them_all_dammit;
1940: Log("CRITICAL","Master process exiting");
1941: exit 0;
1942:
1943: }
1944: =pod
1945:
1946: =head1 Theory
1947:
1948: The event class is used to build this as a single process with an
1949: event driven model. The following events are handled:
1950:
1951: =item UNIX Socket connection Received
1952:
1953: =item Request data arrives on UNIX data transfer socket.
1954:
1955: =item lond connection becomes writable.
1956:
1957: =item timer fires at 1 second intervals.
1958:
1959: All sockets are run in non-blocking mode. Timeouts managed by the timer
1960: handler prevents hung connections.
1961:
1962: Key data structures:
1963:
1964: =item RequestQueue
1965:
1966: A queue of requests received from UNIX sockets that are
1967: waiting for a chance to be forwarded on a lond connection socket.
1968:
1969: =item ActiveConnections
1970:
1971: A hash of lond connections that have transactions in process that are
1972: available to be timed out.
1973:
1974: =item ActiveTransactions
1975:
1976: A hash indexed by lond connections that contain the client reply
1977: socket for each connection that has an active transaction on it.
1978:
1979: =item IdleConnections
1980:
1981: A hash of lond connections that have no work to do. These connections
1982: can be closed if they are idle for a long enough time.
1983:
1984: =cut
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