1: #!/usr/bin/perl
2: # The LearningOnline Network with CAPA
3: # lonc maintains the connections to remote computers
4: #
5: # $Id: loncnew,v 1.57.2.1 2005/01/19 21:38:25 albertel 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: use Fcntl qw(:flock);
65:
66:
67: # Read the httpd configuration file to get perl variables
68: # normally set in apache modules:
69:
70: my $perlvarref = LONCAPA::Configuration::read_conf('loncapa.conf');
71: my %perlvar = %{$perlvarref};
72:
73: #
74: # parent and shared variables.
75:
76: my %ChildHash; # by pid -> host.
77: my %HostToPid; # By host -> pid.
78: my %HostHash; # by loncapaname -> IP.
79:
80:
81: my $MaxConnectionCount = 10; # Will get from config later.
82: my $ClientConnection = 0; # Uniquifier for client events.
83:
84: my $DebugLevel = 0;
85: my $NextDebugLevel= 2; # So Sigint can toggle this.
86: my $IdleTimeout= 600; # Wait 10 minutes before pruning connections.
87:
88: my $LogTransactions = 0; # When True, all transactions/replies get logged.
89:
90: #
91: # The variables below are only used by the child processes.
92: #
93: my $RemoteHost; # Name of host child is talking to.
94: my $UnixSocketDir= $perlvar{'lonSockDir'};
95: my $IdleConnections = Stack->new(); # Set of idle connections
96: my %ActiveConnections; # Connections to the remote lond.
97: my %ActiveTransactions; # LondTransactions in flight.
98: my %ActiveClients; # Serial numbers of active clients by socket.
99: my $WorkQueue = Queue->new(); # Queue of pending transactions.
100: my $ConnectionCount = 0;
101: my $IdleSeconds = 0; # Number of seconds idle.
102: my $Status = ""; # Current status string.
103: my $RecentLogEntry = "";
104: my $ConnectionRetries=2; # Number of connection retries allowed.
105: my $ConnectionRetriesLeft=2; # Number of connection retries remaining.
106: my $LondVersion = "unknown"; # Version of lond we talk with.
107: my $KeyMode = ""; # e.g. ssl, local, insecure from last connect.
108: my $LondConnecting = 0; # True when a connection is being built.
109:
110: my $DieWhenIdle = 0; # When true children die when trimmed -> 0.
111:
112: #
113: # The hash below gives the HTML format for log messages
114: # given a severity.
115: #
116: my %LogFormats;
117:
118: $LogFormats{"CRITICAL"} = "<font color='red'>CRITICAL: %s</font>";
119: $LogFormats{"SUCCESS"} = "<font color='green'>SUCCESS: %s</font>";
120: $LogFormats{"INFO"} = "<font color='yellow'>INFO: %s</font>";
121: $LogFormats{"WARNING"} = "<font color='blue'>WARNING: %s</font>";
122: $LogFormats{"DEFAULT"} = " %s ";
123:
124:
125: # UpdateStatus;
126: # Update the idle status display to show how many connections
127: # are left, retries and other stuff.
128: #
129: sub UpdateStatus {
130: if ($ConnectionRetriesLeft > 0) {
131: ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
132: ." Retries remaining: ".$ConnectionRetriesLeft
133: ." ($KeyMode)");
134: } else {
135: ShowStatus(GetServerHost()." >> DEAD <<");
136: }
137: }
138:
139:
140: =pod
141:
142: =head2 LogPerm
143:
144: Makes an entry into the permanent log file.
145:
146: =cut
147: sub LogPerm {
148: my $message=shift;
149: my $execdir=$perlvar{'lonDaemons'};
150: my $now=time;
151: my $local=localtime($now);
152: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
153: print $fh "$now:$message:$local\n";
154: }
155:
156: =pod
157:
158: =head2 Log
159:
160: Logs a message to the log file.
161: Parameters:
162:
163: =item severity
164:
165: One of CRITICAL, WARNING, INFO, SUCCESS used to select the
166: format string used to format the message. if the severity is
167: not a defined severity the Default format string is used.
168:
169: =item message
170:
171: The base message. In addtion to the format string, the message
172: will be appended to a string containing the name of our remote
173: host and the time will be formatted into the message.
174:
175: =cut
176:
177: sub Log {
178:
179: my ($severity, $message) = @_;
180:
181: if(!$LogFormats{$severity}) {
182: $severity = "DEFAULT";
183: }
184:
185: my $format = $LogFormats{$severity};
186:
187: # Put the window dressing in in front of the message format:
188:
189: my $now = time;
190: my $local = localtime($now);
191: my $finalformat = "$local ($$) [$RemoteHost] [$Status] ";
192: my $finalformat = $finalformat.$format."\n";
193:
194: # open the file and put the result.
195:
196: my $execdir = $perlvar{'lonDaemons'};
197: my $fh = IO::File->new(">>$execdir/logs/lonc.log");
198: my $msg = sprintf($finalformat, $message);
199: $RecentLogEntry = $msg;
200: print $fh $msg;
201:
202:
203: }
204:
205:
206: =pod
207:
208: =head2 GetPeerName
209:
210: Returns the name of the host that a socket object is connected to.
211:
212: =cut
213:
214: sub GetPeername {
215:
216:
217: my ($connection, $AdrFamily) = @_;
218:
219: my $peer = $connection->peername();
220: my $peerport;
221: my $peerip;
222: if($AdrFamily == AF_INET) {
223: ($peerport, $peerip) = sockaddr_in($peer);
224: my $peername = gethostbyaddr($peerip, $AdrFamily);
225: return $peername;
226: } elsif ($AdrFamily == AF_UNIX) {
227: my $peerfile;
228: ($peerfile) = sockaddr_un($peer);
229: return $peerfile;
230: }
231: }
232: =pod
233:
234: =head2 Debug
235:
236: Invoked to issue a debug message.
237:
238: =cut
239:
240: sub Debug {
241:
242: my ($level, $message) = @_;
243:
244: if ($level <= $DebugLevel) {
245: Log("INFO", "-Debug- $message host = $RemoteHost");
246: }
247: }
248:
249: sub SocketDump {
250:
251: my ($level, $socket) = @_;
252:
253: if($level <= $DebugLevel) {
254: $socket->Dump(-1); # Ensure it will get dumped.
255: }
256: }
257:
258: =pod
259:
260: =head2 ShowStatus
261:
262: Place some text as our pid status.
263: and as what we return in a SIGUSR1
264:
265: =cut
266: sub ShowStatus {
267: my $state = shift;
268: my $now = time;
269: my $local = localtime($now);
270: $Status = $local.": ".$state;
271: $0='lonc: '.$state.' '.$local;
272: }
273:
274: =pod
275:
276: =head 2 SocketTimeout
277:
278: Called when an action on the socket times out. The socket is
279: destroyed and any active transaction is failed.
280:
281:
282: =cut
283: sub SocketTimeout {
284: my $Socket = shift;
285: Log("WARNING", "A socket timeout was detected");
286: Debug(5, " SocketTimeout called: ");
287: $Socket->Dump(0);
288: if(exists($ActiveTransactions{$Socket})) {
289: FailTransaction($ActiveTransactions{$Socket});
290: }
291: KillSocket($Socket); # A transaction timeout also counts as
292: # a connection failure:
293: $ConnectionRetriesLeft--;
294: if($ConnectionRetriesLeft <= 0) {
295: Log("CRITICAL", "Host marked DEAD: ".GetServerHost());
296: $LondConnecting = 0;
297: }
298:
299: }
300: #----------------------------- Timer management ------------------------
301:
302: =pod
303:
304: =head2 Tick
305:
306: Invoked each timer tick.
307:
308: =cut
309:
310:
311: sub Tick {
312: my ($Event) = @_;
313: my $clock_watcher = $Event->w;
314:
315: my $client;
316: UpdateStatus();
317:
318: # Is it time to prune connection count:
319:
320:
321: if($IdleConnections->Count() &&
322: ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
323: $IdleSeconds++;
324: if($IdleSeconds > $IdleTimeout) { # Prune a connection...
325: my $Socket = $IdleConnections->pop();
326: KillSocket($Socket);
327: $IdleSeconds = 0; # Otherwise all connections get trimmed to fast.
328: UpdateStatus();
329: if(($ConnectionCount == 0) && $DieWhenIdle) {
330: #
331: # Create a lock file since there will be a time window
332: # between our exit and the parent's picking up the listen
333: # during which no listens will be done on the
334: # lonnet client socket.
335: #
336: my $lock_file = GetLoncSocketPath().".lock";
337: open(LOCK,">$lock_file");
338: print LOCK "Contents not important";
339: close(LOCK);
340:
341: exit(0);
342: }
343: }
344: } else {
345: $IdleSeconds = 0; # Reset idle count if not idle.
346: }
347: #
348: # For each inflight transaction, tick down its timeout counter.
349: #
350:
351: foreach my $item (keys %ActiveConnections) {
352: my $State = $ActiveConnections{$item}->data->GetState();
353: if ($State ne 'Idle') {
354: Debug(5,"Ticking Socket $State $item");
355: $ActiveConnections{$item}->data->Tick();
356: }
357: }
358: # Do we have work in the queue, but no connections to service them?
359: # If so, try to make some new connections to get things going again.
360: #
361: # Note this code is dead now...
362: #
363: my $Requests = $WorkQueue->Count();
364: if (($ConnectionCount == 0) && ($Requests > 0) && (!$LondConnecting)) {
365: if ($ConnectionRetriesLeft > 0) {
366: Debug(5,"Work but no connections, Make a new one");
367: my $success;
368: $success = &MakeLondConnection;
369: if($success == 0) { # All connections failed:
370: Debug(5,"Work in queue failed to make any connectiouns\n");
371: EmptyQueue(); # Fail pending transactions with con_lost.
372: CloseAllLondConnections(); # Should all be closed but....
373: }
374: } else {
375: $LondConnecting = 0;
376: ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
377: Debug(5,"Work in queue, but gave up on connections..flushing\n");
378: EmptyQueue(); # Connections can't be established.
379: CloseAllLondConnections(); # Should all already be closed but...
380: }
381:
382: }
383: if ($ConnectionCount == 0) {
384: $KeyMode = "";
385: $clock_watcher->cancel();
386: }
387: &UpdateStatus();
388: }
389:
390: =pod
391:
392: =head2 SetupTimer
393:
394: Sets up a 1 per sec recurring timer event. The event handler is used to:
395:
396: =item
397:
398: Trigger timeouts on communications along active sockets.
399:
400: =item
401:
402: Trigger disconnections of idle sockets.
403:
404: =cut
405:
406: sub SetupTimer {
407: Debug(6, "SetupTimer");
408: Event->timer(interval => 1, cb => \&Tick );
409: }
410:
411: =pod
412:
413: =head2 ServerToIdle
414:
415: This function is called when a connection to the server is
416: ready for more work.
417:
418: If there is work in the Work queue the top element is dequeued
419: and the connection will start to work on it. If the work queue is
420: empty, the connection is pushed on the idle connection stack where
421: it will either get another work unit, or alternatively, if it sits there
422: long enough, it will be shut down and released.
423:
424: =cut
425:
426: sub ServerToIdle {
427: my $Socket = shift; # Get the socket.
428: $KeyMode = $Socket->{AuthenticationMode};
429: delete($ActiveTransactions{$Socket}); # Server has no transaction
430:
431: &Debug(5, "Server to idle");
432:
433: # If there's work to do, start the transaction:
434:
435: my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
436: if ($reqdata ne undef) {
437: Debug(5, "Queue gave request data: ".$reqdata->getRequest());
438: &StartRequest($Socket, $reqdata);
439:
440: } else {
441:
442: # There's no work waiting, so push the server to idle list.
443: &Debug(5, "No new work requests, server connection going idle");
444: $IdleConnections->push($Socket);
445: }
446: }
447:
448: =pod
449:
450: =head2 ClientWritable
451:
452: Event callback for when a client socket is writable.
453:
454: This callback is established when a transaction reponse is
455: avaiable from lond. The response is forwarded to the unix socket
456: as it becomes writable in this sub.
457:
458: Parameters:
459:
460: =item Event
461:
462: The event that has been triggered. Event->w->data is
463: the data and Event->w->fd is the socket to write.
464:
465: =cut
466:
467: sub ClientWritable {
468: my $Event = shift;
469: my $Watcher = $Event->w;
470: my $Data = $Watcher->data;
471: my $Socket = $Watcher->fd;
472:
473: # Try to send the data:
474:
475: &Debug(6, "ClientWritable writing".$Data);
476: &Debug(9, "Socket is: ".$Socket);
477:
478: if($Socket->connected) {
479: my $result = $Socket->send($Data, 0);
480:
481: # $result undefined: the write failed.
482: # otherwise $result is the number of bytes written.
483: # Remove that preceding string from the data.
484: # If the resulting data is empty, destroy the watcher
485: # and set up a read event handler to accept the next
486: # request.
487:
488: &Debug(9,"Send result is ".$result." Defined: ".defined($result));
489: if($result ne undef) {
490: &Debug(9, "send result was defined");
491: if($result == length($Data)) { # Entire string sent.
492: &Debug(9, "ClientWritable data all written");
493: $Watcher->cancel();
494: #
495: # Set up to read next request from socket:
496:
497: my $descr = sprintf("Connection to lonc client %d",
498: $ActiveClients{$Socket});
499: Event->io(cb => \&ClientRequest,
500: poll => 'r',
501: desc => $descr,
502: data => "",
503: fd => $Socket);
504:
505: } else { # Partial string sent.
506: $Watcher->data(substr($Data, $result));
507: if($result == 0) { # client hung up on us!!
508: # Log("INFO", "lonc pipe client hung up on us!");
509: $Watcher->cancel;
510: $Socket->shutdown(2);
511: $Socket->close();
512: }
513: }
514:
515: } else { # Error of some sort...
516:
517: # Some errnos are possible:
518: my $errno = $!;
519: if($errno == POSIX::EWOULDBLOCK ||
520: $errno == POSIX::EAGAIN ||
521: $errno == POSIX::EINTR) {
522: # No action taken?
523: } else { # Unanticipated errno.
524: &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
525: $Watcher->cancel; # Stop the watcher.
526: $Socket->shutdown(2); # Kill connection
527: $Socket->close(); # Close the socket.
528: }
529:
530: }
531: } else {
532: $Watcher->cancel(); # A delayed request...just cancel.
533: }
534: }
535:
536: =pod
537:
538: =head2 CompleteTransaction
539:
540: Called when the reply data has been received for a lond
541: transaction. The reply data must now be sent to the
542: ultimate client on the other end of the Unix socket. This is
543: done by setting up a writable event for the socket with the
544: data the reply data.
545:
546: Parameters:
547:
548: =item Socket
549:
550: Socket on which the lond transaction occured. This is a
551: LondConnection. The data received is in the TransactionReply member.
552:
553: =item Transaction
554:
555: The transaction that is being completed.
556:
557: =cut
558:
559: sub CompleteTransaction {
560: &Debug(5,"Complete transaction");
561:
562: my ($Socket, $Transaction) = @_;
563:
564: if (!$Transaction->isDeferred()) { # Normal transaction
565: my $data = $Socket->GetReply(); # Data to send.
566: if($LogTransactions) {
567: Log("SUCCESS", "Reply from lond: '$data'");
568: }
569: StartClientReply($Transaction, $data);
570: } else { # Delete deferred transaction file.
571: Log("SUCCESS", "A delayed transaction was completed");
572: LogPerm("S:$Transaction->getClient() :".$Transaction->getRequest());
573: unlink $Transaction->getFile();
574: }
575: }
576:
577: =pod
578:
579: =head1 StartClientReply
580:
581: Initiates a reply to a client where the reply data is a parameter.
582:
583: =head2 parameters:
584:
585: =item Transaction
586:
587: The transaction for which we are responding to the client.
588:
589: =item data
590:
591: The data to send to apached client.
592:
593: =cut
594:
595: sub StartClientReply {
596:
597: my ($Transaction, $data) = @_;
598:
599: my $Client = $Transaction->getClient();
600:
601: &Debug(8," Reply was: ".$data);
602: my $Serial = $ActiveClients{$Client};
603: my $desc = sprintf("Connection to lonc client %d",
604: $Serial);
605: Event->io(fd => $Client,
606: poll => "w",
607: desc => $desc,
608: cb => \&ClientWritable,
609: data => $data);
610: }
611:
612: =pod
613:
614: =head2 FailTransaction
615:
616: Finishes a transaction with failure because the associated lond socket
617: disconnected. There are two possibilities:
618: - The transaction is deferred: in which case we just quietly
619: delete the transaction since there is no client connection.
620: - The transaction is 'live' in which case we initiate the sending
621: of "con_lost" to the client.
622:
623: Deleting the transaction means killing it from the %ActiveTransactions hash.
624:
625: Parameters:
626:
627: =item client
628:
629: The LondTransaction we are failing.
630:
631:
632: =cut
633:
634: sub FailTransaction {
635: my $transaction = shift;
636:
637: # If the socket is dead, that's already logged.
638:
639: if ($ConnectionRetriesLeft > 0) {
640: Log("WARNING", "Failing transaction "
641: .$transaction->getRequest());
642: }
643: Debug(1, "Failing transaction: ".$transaction->getRequest());
644: if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
645: my $client = $transaction->getClient();
646: Debug(1," Replying con_lost to ".$transaction->getRequest());
647: StartClientReply($transaction, "con_lost\n");
648: }
649:
650: }
651:
652: =pod
653: =head1 EmptyQueue
654:
655: Fails all items in the work queue with con_lost.
656: Note that each item in the work queue is a transaction.
657:
658: =cut
659: sub EmptyQueue {
660: $ConnectionRetriesLeft--; # Counts as connection failure too.
661: while($WorkQueue->Count()) {
662: my $request = $WorkQueue->dequeue(); # This is a transaction
663: FailTransaction($request);
664: }
665: }
666:
667: =pod
668:
669: =head2 CloseAllLondConnections
670:
671: Close all connections open on lond prior to exit e.g.
672:
673: =cut
674: sub CloseAllLondConnections {
675: foreach my $Socket (keys %ActiveConnections) {
676: if(exists($ActiveTransactions{$Socket})) {
677: FailTransaction($ActiveTransactions{$Socket});
678: }
679: KillSocket($Socket);
680: }
681: }
682: =cut
683:
684: =pod
685:
686: =head2 KillSocket
687:
688: Destroys a socket. This function can be called either when a socket
689: has died of 'natural' causes or because a socket needs to be pruned due to
690: idleness. If the socket has died naturally, if there are no longer any
691: live connections a new connection is created (in case there are transactions
692: in the queue). If the socket has been pruned, it is never re-created.
693:
694: Parameters:
695:
696: =item Socket
697:
698: The socket to kill off.
699:
700: =item Restart
701:
702: nonzero if we are allowed to create a new connection.
703:
704:
705: =cut
706: sub KillSocket {
707: my $Socket = shift;
708:
709: Log("WARNING", "Shutting down a socket");
710: $Socket->Shutdown();
711:
712: # If the socket came from the active connection set,
713: # delete its transaction... note that FailTransaction should
714: # already have been called!!!
715: # otherwise it came from the idle set.
716: #
717:
718: if(exists($ActiveTransactions{$Socket})) {
719: delete ($ActiveTransactions{$Socket});
720: }
721: if(exists($ActiveConnections{$Socket})) {
722: delete($ActiveConnections{$Socket});
723: $ConnectionCount--;
724: if ($ConnectionCount < 0) { $ConnectionCount = 0; }
725: }
726: # If the connection count has gone to zero and there is work in the
727: # work queue, the work all gets failed with con_lost.
728: #
729: if($ConnectionCount == 0) {
730: EmptyQueue();
731: CloseAllLondConnections; # Should all already be closed but...
732: }
733: }
734:
735: =pod
736:
737: =head2 LondReadable
738:
739: This function is called whenever a lond connection
740: is readable. The action is state dependent:
741:
742: =head3 State=Initialized
743:
744: We''re waiting for the challenge, this is a no-op until the
745: state changes.
746:
747: =head3 State=Challenged
748:
749: The challenge has arrived we need to transition to Writable.
750: The connection must echo the challenge back.
751:
752: =head3 State=ChallengeReplied
753:
754: The challenge has been replied to. The we are receiveing the
755: 'ok' from the partner.
756:
757: =head3 State=ReadingVersionString
758:
759: We have requested the lond version and are reading the
760: version back. Upon completion, we'll store the version away
761: for future use(?).
762:
763: =head3 State=HostSet
764:
765: We have selected the domain name of our peer (multhomed hosts)
766: and are getting the reply (presumably ok) back.
767:
768: =head3 State=RequestingKey
769:
770: The ok has been received and we need to send the request for
771: an encryption key. Transition to writable for that.
772:
773: =head3 State=ReceivingKey
774:
775: The the key has been requested, now we are reading the new key.
776:
777: =head3 State=Idle
778:
779: The encryption key has been negotiated or we have finished
780: reading data from the a transaction. If the callback data has
781: a client as well as the socket iformation, then we are
782: doing a transaction and the data received is relayed to the client
783: before the socket is put on the idle list.
784:
785: =head3 State=SendingRequest
786:
787: I do not think this state can be received here, but if it is,
788: the appropriate thing to do is to transition to writable, and send
789: the request.
790:
791: =head3 State=ReceivingReply
792:
793: We finished sending the request to the server and now transition
794: to readable to receive the reply.
795:
796: The parameter to this function are:
797:
798: The event. Implicit in this is the watcher and its data. The data
799: contains at least the lond connection object and, if a
800: transaction is in progress, the socket attached to the local client.
801:
802: =cut
803:
804: sub LondReadable {
805:
806: my $Event = shift;
807: my $Watcher = $Event->w;
808: my $Socket = $Watcher->data;
809: my $client = undef;
810:
811: &Debug(6,"LondReadable called state = ".$Socket->GetState());
812:
813:
814: my $State = $Socket->GetState(); # All action depends on the state.
815:
816: SocketDump(6, $Socket);
817: my $status = $Socket->Readable();
818:
819: &Debug(2, "Socket->Readable returned: $status");
820:
821: if($status != 0) {
822: # bad return from socket read. Currently this means that
823: # The socket has become disconnected. We fail the transaction.
824:
825: Log("WARNING",
826: "Lond connection lost.");
827: if(exists($ActiveTransactions{$Socket})) {
828: FailTransaction($ActiveTransactions{$Socket});
829: } else {
830: # Socket is connecting and failed... need to mark
831: # no longer connecting.
832:
833: $LondConnecting = 0;
834: }
835: $Watcher->cancel();
836: KillSocket($Socket);
837: $ConnectionRetriesLeft--; # Counts as connection failure
838: return;
839: }
840: SocketDump(6,$Socket);
841:
842: $State = $Socket->GetState(); # Update in case of transition.
843: &Debug(6, "After read, state is ".$State);
844:
845: if($State eq "Initialized") {
846:
847:
848: } elsif ($State eq "ChallengeReceived") {
849: # The challenge must be echoed back; The state machine
850: # in the connection takes care of setting that up. Just
851: # need to transition to writable:
852:
853: $Watcher->cb(\&LondWritable);
854: $Watcher->poll("w");
855:
856: } elsif ($State eq "ChallengeReplied") {
857:
858: } elsif ($State eq "RequestingVersion") {
859: # Need to ask for the version... that is writiability:
860:
861: $Watcher->cb(\&LondWritable);
862: $Watcher->poll("w");
863:
864: } elsif ($State eq "ReadingVersionString") {
865: # Read the rest of the version string...
866: } elsif ($State eq "SetHost") {
867: # Need to request the actual domain get set...
868:
869: $Watcher->cb(\&LondWritable);
870: $Watcher->poll("w");
871: } elsif ($State eq "HostSet") {
872: # Reading the 'ok' from the peer.
873:
874: } elsif ($State eq "RequestingKey") {
875: # The ok was received. Now we need to request the key
876: # That requires us to be writable:
877:
878: $Watcher->cb(\&LondWritable);
879: $Watcher->poll("w");
880:
881: } elsif ($State eq "ReceivingKey") {
882:
883: } elsif ($State eq "Idle") {
884:
885: # This is as good a spot as any to get the peer version
886: # string:
887:
888: if($LondVersion eq "unknown") {
889: $LondVersion = $Socket->PeerVersion();
890: Log("INFO", "Connected to lond version: $LondVersion");
891: }
892: # If necessary, complete a transaction and then go into the
893: # idle queue.
894: # Note that a trasition to idle indicates a live lond
895: # on the other end so reset the connection retries.
896: #
897: $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
898: $Watcher->cancel();
899: if(exists($ActiveTransactions{$Socket})) {
900: Debug(5,"Completing transaction!!");
901: CompleteTransaction($Socket,
902: $ActiveTransactions{$Socket});
903: } else {
904: Log("SUCCESS", "Connection ".$ConnectionCount." to "
905: .$RemoteHost." now ready for action");
906: }
907: ServerToIdle($Socket); # Next work unit or idle.
908:
909: #
910: $LondConnecting = 0; # Best spot I can think of for this.
911: #
912:
913: } elsif ($State eq "SendingRequest") {
914: # We need to be writable for this and probably don't belong
915: # here inthe first place.
916:
917: Deubg(6, "SendingRequest state encountered in readable");
918: $Watcher->poll("w");
919: $Watcher->cb(\&LondWritable);
920:
921: } elsif ($State eq "ReceivingReply") {
922:
923:
924: } else {
925: # Invalid state.
926: Debug(4, "Invalid state in LondReadable");
927: }
928: }
929:
930: =pod
931:
932: =head2 LondWritable
933:
934: This function is called whenever a lond connection
935: becomes writable while there is a writeable monitoring
936: event. The action taken is very state dependent:
937:
938: =head3 State = Connected
939:
940: The connection is in the process of sending the 'init' hailing to the
941: lond on the remote end. The connection object''s Writable member is
942: called. On error, ConnectionError is called to destroy the connection
943: and remove it from the ActiveConnections hash
944:
945: =head3 Initialized
946:
947: 'init' has been sent, writability monitoring is removed and
948: readability monitoring is started with LondReadable as the callback.
949:
950: =head3 ChallengeReceived
951:
952: The connection has received the who are you challenge from the remote
953: system, and is in the process of sending the challenge
954: response. Writable is called.
955:
956: =head3 ChallengeReplied
957:
958: The connection has replied to the initial challenge The we switch to
959: monitoring readability looking for the server to reply with 'ok'.
960:
961: =head3 RequestingKey
962:
963: The connection is in the process of requesting its encryption key.
964: Writable is called.
965:
966: =head3 ReceivingKey
967:
968: The connection has sent the request for a key. Switch to readability
969: monitoring to accept the key
970:
971: =head3 SendingRequest
972:
973: The connection is in the process of sending a request to the server.
974: This request is part of a client transaction. All the states until
975: now represent the client setup protocol. Writable is called.
976:
977: =head3 ReceivingReply
978:
979: The connection has sent a request. Now it must receive a reply.
980: Readability monitoring is requested.
981:
982: This function is an event handler and therefore receives as
983: a parameter the event that has fired. The data for the watcher
984: of this event is a reference to a list of one or two elements,
985: depending on state. The first (and possibly only) element is the
986: socket. The second (present only if a request is in progress)
987: is the socket on which to return a reply to the caller.
988:
989: =cut
990:
991: sub LondWritable {
992: my $Event = shift;
993: my $Watcher = $Event->w;
994: my $Socket = $Watcher->data;
995: my $State = $Socket->GetState();
996:
997: Debug(6,"LondWritable State = ".$State."\n");
998:
999:
1000: # Figure out what to do depending on the state of the socket:
1001:
1002:
1003:
1004:
1005: SocketDump(6,$Socket);
1006:
1007: # If the socket is writable, we must always write.
1008: # Only by writing will we undergo state transitions.
1009: # Old logic wrote in state specific code below, however
1010: # That forces us at least through another invocation of
1011: # this function after writability is possible again.
1012: # This logic also factors out common code for handling
1013: # write failures... in all cases, write failures
1014: # Kill the socket.
1015: # This logic makes the branches of the >big< if below
1016: # so that the writing states are actually NO-OPs.
1017:
1018: if ($Socket->Writable() != 0) {
1019: # The write resulted in an error.
1020: # We'll treat this as if the socket got disconnected:
1021: Log("WARNING", "Connection to ".$RemoteHost.
1022: " has been disconnected");
1023: if(exists($ActiveTransactions{$Socket})) {
1024: FailTransaction($ActiveTransactions{$Socket});
1025: } else {
1026: # In the process of conneting, so need to turn that off.
1027:
1028: $LondConnecting = 0;
1029: }
1030: $Watcher->cancel();
1031: KillSocket($Socket);
1032: return;
1033: }
1034:
1035:
1036:
1037: if ($State eq "Connected") {
1038:
1039: # "init" is being sent...
1040:
1041: } elsif ($State eq "Initialized") {
1042:
1043: # Now that init was sent, we switch
1044: # to watching for readability:
1045:
1046: $Watcher->cb(\&LondReadable);
1047: $Watcher->poll("r");
1048:
1049: } elsif ($State eq "ChallengeReceived") {
1050: # We received the challenge, now we
1051: # are echoing it back. This is a no-op,
1052: # we're waiting for the state to change
1053:
1054: } elsif ($State eq "ChallengeReplied") {
1055: # The echo was sent back, so we switch
1056: # to watching readability.
1057:
1058: $Watcher->cb(\&LondReadable);
1059: $Watcher->poll("r");
1060: } elsif ($State eq "RequestingVersion") {
1061: # Sending the peer a version request...
1062:
1063: } elsif ($State eq "ReadingVersionString") {
1064: # Transition to read since we have sent the
1065: # version command and now just need to read the
1066: # version string from the peer:
1067:
1068: $Watcher->cb(\&LondReadable);
1069: $Watcher->poll("r");
1070:
1071: } elsif ($State eq "SetHost") {
1072: # Setting the remote domain...
1073:
1074: } elsif ($State eq "HostSet") {
1075: # Back to readable to get the ok.
1076:
1077: $Watcher->cb(\&LondReadable);
1078: $Watcher->poll("r");
1079:
1080:
1081: } elsif ($State eq "RequestingKey") {
1082: # At this time we're requesting the key.
1083: # again, this is essentially a no-op.
1084:
1085: } elsif ($State eq "ReceivingKey") {
1086: # Now we need to wait for the key
1087: # to come back from the peer:
1088:
1089: $Watcher->cb(\&LondReadable);
1090: $Watcher->poll("r");
1091:
1092: } elsif ($State eq "SendingRequest") {
1093:
1094: # At this time we are sending a request to the
1095: # peer... write the next chunk:
1096:
1097:
1098: } elsif ($State eq "ReceivingReply") {
1099: # The send has completed. Wait for the
1100: # data to come in for a reply.
1101: Debug(8,"Writable sent request/receiving reply");
1102: $Watcher->cb(\&LondReadable);
1103: $Watcher->poll("r");
1104:
1105: } else {
1106: # Control only passes here on an error:
1107: # the socket state does not match any
1108: # of the known states... so an error
1109: # must be logged.
1110:
1111: &Debug(4, "Invalid socket state ".$State."\n");
1112: }
1113:
1114: }
1115: =pod
1116:
1117: =cut
1118: sub QueueDelayed {
1119: Debug(3,"QueueDelayed called");
1120:
1121: my $path = "$perlvar{'lonSockDir'}/delayed";
1122:
1123: Debug(4, "Delayed path: ".$path);
1124: opendir(DIRHANDLE, $path);
1125:
1126: my @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
1127: closedir(DIRHANDLE);
1128: my $dfname;
1129: my $reqfile;
1130: foreach $dfname (sort @alldelayed) {
1131: $reqfile = "$path/$dfname";
1132: Debug(4, "queueing ".$reqfile);
1133: my $Handle = IO::File->new($reqfile);
1134: my $cmd = <$Handle>;
1135: chomp $cmd; # There may or may not be a newline...
1136: $cmd = $cmd."\n"; # now for sure there's exactly one newline.
1137: my $Transaction = LondTransaction->new($cmd);
1138: $Transaction->SetDeferred($reqfile);
1139: QueueTransaction($Transaction);
1140: }
1141:
1142: }
1143:
1144: =pod
1145:
1146: =head2 MakeLondConnection
1147:
1148: Create a new lond connection object, and start it towards its initial
1149: idleness. Once idle, it becomes elligible to receive transactions
1150: from the work queue. If the work queue is not empty when the
1151: connection is completed and becomes idle, it will dequeue an entry and
1152: start off on it.
1153:
1154: =cut
1155:
1156: sub MakeLondConnection {
1157: Debug(4,"MakeLondConnection to ".GetServerHost()." on port "
1158: .GetServerPort());
1159:
1160: my $Connection = LondConnection->new(&GetServerHost(),
1161: &GetServerPort());
1162:
1163: if($Connection eq undef) { # Needs to be more robust later.
1164: Log("CRITICAL","Failed to make a connection with lond.");
1165: $ConnectionRetriesLeft--;
1166: return 0; # Failure.
1167: } else {
1168:
1169: # The connection needs to have writability
1170: # monitored in order to send the init sequence
1171: # that starts the whole authentication/key
1172: # exchange underway.
1173: #
1174: my $Socket = $Connection->GetSocket();
1175: if($Socket eq undef) {
1176: die "did not get a socket from the connection";
1177: } else {
1178: &Debug(9,"MakeLondConnection got socket: ".$Socket);
1179: }
1180:
1181: $Connection->SetTimeoutCallback(\&SocketTimeout);
1182:
1183: my $event = Event->io(fd => $Socket,
1184: poll => 'w',
1185: cb => \&LondWritable,
1186: data => $Connection,
1187: desc => 'Connection to lond server');
1188: $ActiveConnections{$Connection} = $event;
1189: if ($ConnectionCount == 0) {
1190: &SetupTimer; # Need to handle timeouts with connections...
1191: }
1192: $ConnectionCount++;
1193: Debug(4, "Connection count = ".$ConnectionCount);
1194: if($ConnectionCount == 1) { # First Connection:
1195: QueueDelayed;
1196: }
1197: Log("SUCESS", "Created connection ".$ConnectionCount
1198: ." to host ".GetServerHost());
1199: $LondConnecting = 1; # Connection in progress.
1200: return 1; # Return success.
1201: }
1202:
1203: }
1204:
1205: =pod
1206:
1207: =head2 StartRequest
1208:
1209: Starts a lond request going on a specified lond connection.
1210: parameters are:
1211:
1212: =item $Lond
1213:
1214: Connection to the lond that will send the transaction and receive the
1215: reply.
1216:
1217: =item $Client
1218:
1219: Connection to the client that is making this request We got the
1220: request from this socket, and when the request has been relayed to
1221: lond and we get a reply back from lond it will get sent to this
1222: socket.
1223:
1224: =item $Request
1225:
1226: The text of the request to send.
1227:
1228: =cut
1229:
1230: sub StartRequest {
1231:
1232: my ($Lond, $Request) = @_;
1233:
1234: Debug(6, "StartRequest: ".$Request->getRequest());
1235:
1236: my $Socket = $Lond->GetSocket();
1237:
1238: $Request->Activate($Lond);
1239: $ActiveTransactions{$Lond} = $Request;
1240:
1241: $Lond->InitiateTransaction($Request->getRequest());
1242: my $event = Event->io(fd => $Socket,
1243: poll => "w",
1244: cb => \&LondWritable,
1245: data => $Lond,
1246: desc => "lond transaction connection");
1247: $ActiveConnections{$Lond} = $event;
1248: Debug(8," Start Request made watcher data with ".$event->data."\n");
1249: }
1250:
1251: =pod
1252:
1253: =head2 QueueTransaction
1254:
1255: If there is an idle lond connection, it is put to work doing this
1256: transaction. Otherwise, the transaction is placed in the work queue.
1257: If placed in the work queue and the maximum number of connections has
1258: not yet been created, a new connection will be started. Our goal is
1259: to eventually have a sufficient number of connections that the work
1260: queue will typically be empty. parameters are:
1261:
1262: =item Socket
1263:
1264: open on the lonc client.
1265:
1266: =item Request
1267:
1268: data to send to the lond.
1269:
1270: =cut
1271:
1272: sub QueueTransaction {
1273:
1274: my $requestData = shift; # This is a LondTransaction.
1275: my $cmd = $requestData->getRequest();
1276:
1277: Debug(6,"QueueTransaction: ".$cmd);
1278:
1279: my $LondSocket = $IdleConnections->pop();
1280: if(!defined $LondSocket) { # Need to queue request.
1281: Debug(5,"Must queue...");
1282: $WorkQueue->enqueue($requestData);
1283: Debug(5, "Queue Transaction startnew $ConnectionCount $LondConnecting");
1284: if(($ConnectionCount < $MaxConnectionCount) && (! $LondConnecting)) {
1285:
1286: if($ConnectionRetriesLeft > 0) {
1287: Debug(5,"Starting additional lond connection");
1288: if(&MakeLondConnection() == 0) {
1289: EmptyQueue(); # Fail transactions, can't make connection.
1290: CloseAllLondConnections; # Should all be closed but...
1291: }
1292: } else {
1293: ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
1294: $LondConnecting = 0;
1295: EmptyQueue(); # It's worse than that ... he's dead Jim.
1296: CloseAllLondConnections; # Should all be closed but..
1297: }
1298: }
1299: } else { # Can start the request:
1300: Debug(8,"Can start...");
1301: StartRequest($LondSocket, $requestData);
1302: }
1303: }
1304:
1305: #-------------------------- Lonc UNIX socket handling ---------------------
1306:
1307: =pod
1308:
1309: =head2 ClientRequest
1310: Callback that is called when data can be read from the UNIX domain
1311: socket connecting us with an apache server process.
1312:
1313: =cut
1314:
1315: sub ClientRequest {
1316: Debug(6, "ClientRequest");
1317: my $event = shift;
1318: my $watcher = $event->w;
1319: my $socket = $watcher->fd;
1320: my $data = $watcher->data;
1321: my $thisread;
1322:
1323: Debug(9, " Watcher named: ".$watcher->desc);
1324:
1325: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1326: Debug(8, "rcv: data length = ".length($thisread)
1327: ." read =".$thisread);
1328: unless (defined $rv && length($thisread)) {
1329: # Likely eof on socket.
1330: Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
1331: close($socket);
1332: $watcher->cancel();
1333: delete($ActiveClients{$socket});
1334: return;
1335: }
1336: Debug(8,"Data: ".$data." this read: ".$thisread);
1337: $data = $data.$thisread; # Append new data.
1338: $watcher->data($data);
1339: if($data =~ /\n$/) { # Request entirely read.
1340: if($data eq "close_connection_exit\n") {
1341: Log("CRITICAL",
1342: "Request Close Connection ... exiting");
1343: CloseAllLondConnections();
1344: exit;
1345: }
1346: Debug(8, "Complete transaction received: ".$data);
1347: if($LogTransactions) {
1348: Log("SUCCESS", "Transaction: '$data'"); # Transaction has \n.
1349: }
1350: my $Transaction = LondTransaction->new($data);
1351: $Transaction->SetClient($socket);
1352: QueueTransaction($Transaction);
1353: $watcher->cancel(); # Done looking for input data.
1354: }
1355:
1356: }
1357:
1358:
1359: =pod
1360:
1361: =head2 NewClient
1362:
1363: Callback that is called when a connection is received on the unix
1364: socket for a new client of lonc. The callback is parameterized by the
1365: event.. which is a-priori assumed to be an io event, and therefore has
1366: an fd member that is the Listener socket. We Accept the connection
1367: and register a new event on the readability of that socket:
1368:
1369: =cut
1370:
1371: sub NewClient {
1372: Debug(6, "NewClient");
1373: my $event = shift; # Get the event parameters.
1374: my $watcher = $event->w;
1375: my $socket = $watcher->fd; # Get the event' socket.
1376: my $connection = $socket->accept(); # Accept the client connection.
1377: Debug(8,"Connection request accepted from "
1378: .GetPeername($connection, AF_UNIX));
1379:
1380:
1381: my $description = sprintf("Connection to lonc client %d",
1382: $ClientConnection);
1383: Debug(9, "Creating event named: ".$description);
1384: Event->io(cb => \&ClientRequest,
1385: poll => 'r',
1386: desc => $description,
1387: data => "",
1388: fd => $connection);
1389: $ActiveClients{$connection} = $ClientConnection;
1390: $ClientConnection++;
1391: }
1392:
1393: =pod
1394:
1395: =head2 GetLoncSocketPath
1396:
1397: Returns the name of the UNIX socket on which to listen for client
1398: connections.
1399:
1400: =cut
1401:
1402: sub GetLoncSocketPath {
1403: return $UnixSocketDir."/".GetServerHost();
1404: }
1405:
1406: =pod
1407:
1408: =head2 GetServerHost
1409:
1410: Returns the host whose lond we talk with.
1411:
1412: =cut
1413:
1414: sub GetServerHost {
1415: return $RemoteHost; # Setup by the fork.
1416: }
1417:
1418: =pod
1419:
1420: =head2 GetServerPort
1421:
1422: Returns the lond port number.
1423:
1424: =cut
1425:
1426: sub GetServerPort {
1427: return $perlvar{londPort};
1428: }
1429:
1430: =pod
1431:
1432: =head2 SetupLoncListener
1433:
1434: Setup a lonc listener event. The event is called when the socket
1435: becomes readable.. that corresponds to the receipt of a new
1436: connection. The event handler established will accept the connection
1437: (creating a communcations channel), that int turn will establish
1438: another event handler to subess requests.
1439:
1440: =cut
1441:
1442: sub SetupLoncListener {
1443:
1444: my $socket;
1445: my $SocketName = GetLoncSocketPath();
1446: unlink($SocketName);
1447: unless ($socket =IO::Socket::UNIX->new(Local => $SocketName,
1448: Listen => 250,
1449: Type => SOCK_STREAM)) {
1450: die "Failed to create a lonc listner socket";
1451: }
1452: Event->io(cb => \&NewClient,
1453: poll => 'r',
1454: desc => 'Lonc listener Unix Socket',
1455: fd => $socket);
1456: }
1457:
1458: #
1459: # Toggle transaction logging.
1460: # Implicit inputs:
1461: # LogTransactions
1462: # Implicit Outputs:
1463: # LogTransactions
1464: sub ToggleTransactionLogging {
1465: print STDERR "Toggle transaction logging...\n";
1466: if(!$LogTransactions) {
1467: $LogTransactions = 1;
1468: } else {
1469: $LogTransactions = 0;
1470: }
1471:
1472:
1473: Log("SUCCESS", "Toggled transaction logging: $LogTransactions \n");
1474: }
1475:
1476: =pod
1477:
1478: =head2 ChildStatus
1479:
1480: Child USR1 signal handler to report the most recent status
1481: into the status file.
1482:
1483: We also use this to reset the retries count in order to allow the
1484: client to retry connections with a previously dead server.
1485: =cut
1486:
1487: sub ChildStatus {
1488: my $event = shift;
1489: my $watcher = $event->w;
1490:
1491: Debug(2, "Reporting child status because : ".$watcher->data);
1492: my $docdir = $perlvar{'lonDocRoot'};
1493:
1494: open(LOG,">>$docdir/lon-status/loncstatus.txt");
1495: flock(LOG,LOCK_EX);
1496: print LOG $$."\t".$RemoteHost."\t".$Status."\t".
1497: $RecentLogEntry."\n";
1498: #
1499: # Write out information about each of the connections:
1500: #
1501: if ($DebugLevel > 2) {
1502: print LOG "Active connection statuses: \n";
1503: my $i = 1;
1504: print STDERR "================================= Socket Status Dump:\n";
1505: foreach my $item (keys %ActiveConnections) {
1506: my $Socket = $ActiveConnections{$item}->data;
1507: my $state = $Socket->GetState();
1508: print LOG "Connection $i State: $state\n";
1509: print STDERR "---------------------- Connection $i \n";
1510: $Socket->Dump(-1); # Ensure it gets dumped..
1511: $i++;
1512: }
1513: }
1514: flock(LOG,LOCK_UN);
1515: close(LOG);
1516: $ConnectionRetriesLeft = $ConnectionRetries;
1517: }
1518:
1519: =pod
1520:
1521: =head2 SignalledToDeath
1522:
1523: Called in response to a signal that causes a chid process to die.
1524:
1525: =cut
1526:
1527:
1528: sub SignalledToDeath {
1529: my $event = shift;
1530: my $watcher= $event->w;
1531:
1532: Debug(2,"Signalled to death! via ".$watcher->data);
1533: my ($signal) = $watcher->data;
1534: chomp($signal);
1535: Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "
1536: ."died through "."\"$signal\"");
1537: LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
1538: ."\"$signal\"");
1539: exit 0;
1540:
1541: }
1542:
1543: =head2 ToggleDebug
1544:
1545: This sub toggles trace debugging on and off.
1546:
1547: =cut
1548:
1549: sub ToggleDebug {
1550: my $Current = $DebugLevel;
1551: $DebugLevel = $NextDebugLevel;
1552: $NextDebugLevel = $Current;
1553:
1554: Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
1555:
1556: }
1557:
1558: =head2 ChildProcess
1559:
1560: This sub implements a child process for a single lonc daemon.
1561:
1562: =cut
1563:
1564: sub ChildProcess {
1565:
1566:
1567: #
1568: # Signals must be handled by the Event framework...
1569: #
1570:
1571: Event->signal(signal => "QUIT",
1572: cb => \&SignalledToDeath,
1573: data => "QUIT");
1574: Event->signal(signal => "HUP",
1575: cb => \&ChildStatus,
1576: data => "HUP");
1577: Event->signal(signal => "USR1",
1578: cb => \&ChildStatus,
1579: data => "USR1");
1580: Event->signal(signal => "USR2",
1581: cb => \&ToggleTransactionLogging);
1582: Event->signal(signal => "INT",
1583: cb => \&ToggleDebug,
1584: data => "INT");
1585:
1586:
1587: SetupLoncListener();
1588:
1589: $Event::Debuglevel = $DebugLevel;
1590:
1591: Debug(9, "Making initial lond connection for ".$RemoteHost);
1592:
1593: # Setup the initial server connection:
1594:
1595: # &MakeLondConnection(); // let first work requirest do it.
1596:
1597:
1598: Debug(9,"Entering event loop");
1599: my $ret = Event::loop(); # Start the main event loop.
1600:
1601:
1602: die "Main event loop exited!!!";
1603: }
1604:
1605: # Create a new child for host passed in:
1606:
1607: sub CreateChild {
1608: my $host = shift;
1609:
1610: my $sigset = POSIX::SigSet->new(SIGINT);
1611: sigprocmask(SIG_BLOCK, $sigset);
1612: $RemoteHost = $host;
1613: Log("CRITICAL", "Forking server for ".$host);
1614: my $pid = fork;
1615: if($pid) { # Parent
1616: $RemoteHost = "Parent";
1617: $ChildHash{$pid} = $host;
1618: $HostToPid{$host}= $pid;
1619: sigprocmask(SIG_UNBLOCK, $sigset);
1620:
1621: } else { # child.
1622: ShowStatus("Connected to ".$RemoteHost);
1623: $SIG{INT} = 'DEFAULT';
1624: sigprocmask(SIG_UNBLOCK, $sigset);
1625: ChildProcess; # Does not return.
1626: }
1627:
1628: }
1629: #
1630: # Parent process logic pass 1:
1631: # For each entry in the hosts table, we will
1632: # fork off an instance of ChildProcess to service the transactions
1633: # to that host. Each pid will be entered in a global hash
1634: # with the value of the key, the host.
1635: # The parent will then enter a loop to wait for process exits.
1636: # Each exit gets logged and the child gets restarted.
1637: #
1638:
1639: #
1640: # Fork and start in new session so hang-up isn't going to
1641: # happen without intent.
1642: #
1643:
1644:
1645:
1646:
1647:
1648:
1649: ShowStatus("Forming new session");
1650: my $childpid = fork;
1651: if ($childpid != 0) {
1652: sleep 4; # Give child a chacne to break to
1653: exit 0; # a new sesion.
1654: }
1655: #
1656: # Write my pid into the pid file so I can be located
1657: #
1658:
1659: ShowStatus("Parent writing pid file:");
1660: my $execdir = $perlvar{'lonDaemons'};
1661: open (PIDSAVE, ">$execdir/logs/lonc.pid");
1662: print PIDSAVE "$$\n";
1663: close(PIDSAVE);
1664:
1665:
1666:
1667: if (POSIX::setsid() < 0) {
1668: print "Could not create new session\n";
1669: exit -1;
1670: }
1671:
1672: ShowStatus("Forking node servers");
1673:
1674: Log("CRITICAL", "--------------- Starting children ---------------");
1675:
1676: LondConnection::ReadConfig; # Read standard config files.
1677: my $HostIterator = LondConnection::GetHostIterator;
1678: while (! $HostIterator->end()) {
1679:
1680: my $hostentryref = $HostIterator->get();
1681: CreateChild($hostentryref->[0]);
1682: $HostHash{$hostentryref->[0]} = $hostentryref->[4];
1683: $HostIterator->next();
1684: }
1685: $RemoteHost = "Parent Server";
1686:
1687: # Maintain the population:
1688:
1689: ShowStatus("Parent keeping the flock");
1690:
1691: #
1692: # Set up parent signals:
1693: #
1694:
1695: $SIG{INT} = \&Terminate;
1696: $SIG{TERM} = \&Terminate;
1697: $SIG{HUP} = \&Restart;
1698: $SIG{USR1} = \&CheckKids;
1699: $SIG{USR2} = \&UpdateKids; # LonManage update request.
1700:
1701: while(1) {
1702: my $deadchild = wait();
1703: if(exists $ChildHash{$deadchild}) { # need to restart.
1704: my $deadhost = $ChildHash{$deadchild};
1705: delete($HostToPid{$deadhost});
1706: delete($ChildHash{$deadchild});
1707: Log("WARNING","Lost child pid= ".$deadchild.
1708: "Connected to host ".$deadhost);
1709: Log("INFO", "Restarting child procesing ".$deadhost);
1710: CreateChild($deadhost);
1711: }
1712: }
1713:
1714:
1715:
1716: =pod
1717:
1718: =head1 CheckKids
1719:
1720: Since kids do not die as easily in this implementation
1721: as the previous one, there is no need to restart the
1722: dead ones (all dead kids get restarted when they die!!)
1723: The only thing this function does is to pass USR1 to the
1724: kids so that they report their status.
1725:
1726: =cut
1727:
1728: sub CheckKids {
1729: Debug(2, "Checking status of children");
1730: my $docdir = $perlvar{'lonDocRoot'};
1731: my $fh = IO::File->new(">$docdir/lon-status/loncstatus.txt");
1732: my $now=time;
1733: my $local=localtime($now);
1734: print $fh "LONC status $local - parent $$ \n\n";
1735: foreach my $pid (keys %ChildHash) {
1736: Debug(2, "Sending USR1 -> $pid");
1737: kill 'USR1' => $pid; # Tell Child to report status.
1738: }
1739: }
1740:
1741: =pod
1742:
1743: =head1 UpdateKids
1744:
1745: parent's SIGUSR2 handler. This handler:
1746:
1747: =item
1748:
1749: Rereads the hosts file.
1750:
1751: =item
1752:
1753: Kills off (via sigint) children for hosts that have disappeared.
1754:
1755: =item
1756:
1757: QUITs children for hosts that already exist (this just forces a status display
1758: and resets the connection retry count for that host.
1759:
1760: =item
1761:
1762: Starts new children for hosts that have been added to the hosts.tab file since
1763: the start of the master program and maintains them.
1764:
1765: =cut
1766:
1767: sub UpdateKids {
1768:
1769: Log("INFO", "Updating connections via SIGUSR2");
1770:
1771: # Just in case we need to kill our own lonc, we wait a few seconds to
1772: # give it a chance to receive and relay lond's response to the
1773: # re-init command.
1774: #
1775:
1776: sleep(2); # Wait a couple of seconds.
1777:
1778: my %hosts; # Indexed by loncapa hostname, value=ip.
1779:
1780: # Need to re-read the host table:
1781:
1782:
1783: LondConnection::ReadConfig();
1784: my $I = LondConnection::GetHostIterator;
1785: while (! $I->end()) {
1786: my $item = $I->get();
1787: $hosts{$item->[0]} = $item->[4];
1788: $I->next();
1789: }
1790:
1791: # The logic below is written for clarity not for efficiency.
1792: # Since I anticipate that this function is only rarely called, that's
1793: # appropriate. There are certainly ways to combine the loops below,
1794: # and anyone wishing to obscure the logic is welcome to go for it.
1795: # Note that we don't re-direct sigchild. Instead we do what's needed
1796: # to the data structures that keep track of children to ensure that
1797: # when sigchild is honored, no new child is born.
1798: #
1799:
1800: # For each existing child; if it's host doesn't exist, kill the child.
1801:
1802: foreach my $child (keys %ChildHash) {
1803: my $oldhost = $ChildHash{$child};
1804: if (!(exists $hosts{$oldhost})) {
1805: Log("CRITICAL", "Killing child for $oldhost host no longer exists");
1806: delete $ChildHash{$child};
1807: delete $HostToPid{$oldhost};
1808: kill 'QUIT' => $child;
1809: }
1810: }
1811: # For each remaining existing child; if it's host's ip has changed,
1812: # Restart the child on the new IP.
1813:
1814: foreach my $child (keys %ChildHash) {
1815: my $oldhost = $ChildHash{$child};
1816: my $oldip = $HostHash{$oldhost};
1817: if ($hosts{$oldhost} ne $oldip) {
1818:
1819: # kill the old child.
1820:
1821: Log("CRITICAL", "Killing child for $oldhost host ip has changed...");
1822: delete $ChildHash{$child};
1823: delete $HostToPid{$oldhost};
1824: kill 'QUIT' => $child;
1825:
1826: # Do the book-keeping needed to start a new child on the
1827: # new ip.
1828:
1829: $HostHash{$oldhost} = $hosts{$oldhost};
1830: CreateChild($oldhost);
1831: }
1832: }
1833: # Finally, for each new host, not in the host hash, create a
1834: # enter the host and create a new child.
1835: # Force a status display of any existing process.
1836:
1837: foreach my $host (keys %hosts) {
1838: if(!(exists $HostHash{$host})) {
1839: Log("INFO", "New host $host discovered in hosts.tab...");
1840: $HostHash{$host} = $hosts{$host};
1841: CreateChild($host);
1842: } else {
1843: kill 'HUP' => $HostToPid{$host}; # status display.
1844: }
1845: }
1846: }
1847:
1848:
1849: =pod
1850:
1851: =head1 Restart
1852:
1853: Signal handler for HUP... all children are killed and
1854: we self restart. This is an el-cheapo way to re read
1855: the config file.
1856:
1857: =cut
1858:
1859: sub Restart {
1860: &KillThemAll; # First kill all the children.
1861: Log("CRITICAL", "Restarting");
1862: my $execdir = $perlvar{'lonDaemons'};
1863: unlink("$execdir/logs/lonc.pid");
1864: exec("$execdir/loncnew");
1865: }
1866:
1867: =pod
1868:
1869: =head1 KillThemAll
1870:
1871: Signal handler that kills all children by sending them a
1872: SIGHUP. Responds to sigint and sigterm.
1873:
1874: =cut
1875:
1876: sub KillThemAll {
1877: Debug(2, "Kill them all!!");
1878: local($SIG{CHLD}) = 'IGNORE'; # Our children >will< die.
1879: foreach my $pid (keys %ChildHash) {
1880: my $serving = $ChildHash{$pid};
1881: ShowStatus("Nicely Killing lonc for $serving pid = $pid");
1882: Log("CRITICAL", "Nicely Killing lonc for $serving pid = $pid");
1883: kill 'QUIT' => $pid;
1884: }
1885:
1886:
1887: }
1888:
1889:
1890: #
1891: # Kill all children via KILL. Just in case the
1892: # first shot didn't get them.
1893:
1894: sub really_kill_them_all_dammit
1895: {
1896: Debug(2, "Kill them all Dammit");
1897: local($SIG{CHLD} = 'IGNORE'); # In case some purist reenabled them.
1898: foreach my $pid (keys %ChildHash) {
1899: my $serving = $ChildHash{$pid};
1900: &ShowStatus("Nastily killing lonc for $serving pid = $pid");
1901: Log("CRITICAL", "Nastily killing lonc for $serving pid = $pid");
1902: kill 'KILL' => $pid;
1903: delete($ChildHash{$pid});
1904: my $execdir = $perlvar{'lonDaemons'};
1905: unlink("$execdir/logs/lonc.pid");
1906: }
1907: }
1908: =pod
1909:
1910: =head1 Terminate
1911:
1912: Terminate the system.
1913:
1914: =cut
1915:
1916: sub Terminate {
1917: &Log("CRITICAL", "Asked to kill children.. first be nice...");
1918: &KillThemAll;
1919: #
1920: # By now they really should all be dead.. but just in case
1921: # send them all SIGKILL's after a bit of waiting:
1922:
1923: sleep(4);
1924: &Log("CRITICAL", "Now kill children nasty");
1925: &really_kill_them_all_dammit;
1926: Log("CRITICAL","Master process exiting");
1927: exit 0;
1928:
1929: }
1930: =pod
1931:
1932: =head1 Theory
1933:
1934: The event class is used to build this as a single process with an
1935: event driven model. The following events are handled:
1936:
1937: =item UNIX Socket connection Received
1938:
1939: =item Request data arrives on UNIX data transfer socket.
1940:
1941: =item lond connection becomes writable.
1942:
1943: =item timer fires at 1 second intervals.
1944:
1945: All sockets are run in non-blocking mode. Timeouts managed by the timer
1946: handler prevents hung connections.
1947:
1948: Key data structures:
1949:
1950: =item RequestQueue
1951:
1952: A queue of requests received from UNIX sockets that are
1953: waiting for a chance to be forwarded on a lond connection socket.
1954:
1955: =item ActiveConnections
1956:
1957: A hash of lond connections that have transactions in process that are
1958: available to be timed out.
1959:
1960: =item ActiveTransactions
1961:
1962: A hash indexed by lond connections that contain the client reply
1963: socket for each connection that has an active transaction on it.
1964:
1965: =item IdleConnections
1966:
1967: A hash of lond connections that have no work to do. These connections
1968: can be closed if they are idle for a long enough time.
1969:
1970: =cut
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>
![[BACK]](/icons/back.gif){kind=icon}
Return to loncnew CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [LON-CAPA] / loncom