1: #!/usr/bin/perl
2: # The LearningOnline Network with CAPA
3: # lonc maintains the connections to remote computers
4: #
5: # $Id: loncnew,v 1.92 2010/12/21 11:17:03 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 Fcntl qw(:flock);
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 %ChildPid; # by pid -> host.
76: my %ChildHost; # by host.
77: my %listening_to; # Socket->host table for who the parent
78: # is listening to.
79: my %parent_dispatchers; # host-> listener watcher events.
80:
81: my %parent_handlers; # Parent signal handlers...
82:
83: my $MaxConnectionCount = 10; # Will get from config later.
84: my $ClientConnection = 0; # Uniquifier for client events.
85:
86: my $DebugLevel = 0;
87: my $NextDebugLevel= 2; # So Sigint can toggle this.
88: my $IdleTimeout= 7200; # Wait two hours before pruning connections.
89:
90: my $LogTransactions = 0; # When True, all transactions/replies get logged.
91: my $executable = $0; # Get the full path to me.
92:
93: #
94: # The variables below are only used by the child processes.
95: #
96: my $RemoteHost; # Name of host child is talking to.
97: my $RemoteHostId; # default lonid of host child is talking to.
98: my @all_host_ids;
99: my $UnixSocketDir= $perlvar{'lonSockDir'};
100: my $IdleConnections = Stack->new(); # Set of idle connections
101: my %ActiveConnections; # Connections to the remote lond.
102: my %ActiveTransactions; # LondTransactions in flight.
103: my %ActiveClients; # Serial numbers of active clients by socket.
104: my $WorkQueue = Queue->new(); # Queue of pending transactions.
105: my $ConnectionCount = 0;
106: my $IdleSeconds = 0; # Number of seconds idle.
107: my $Status = ""; # Current status string.
108: my $RecentLogEntry = "";
109: my $ConnectionRetries=5; # Number of connection retries allowed.
110: my $ConnectionRetriesLeft=5; # Number of connection retries remaining.
111: my $LondVersion = "unknown"; # Version of lond we talk with.
112: my $KeyMode = ""; # e.g. ssl, local, insecure from last connect.
113: my $LondConnecting = 0; # True when a connection is being built.
114:
115:
116:
117: my $I_am_child = 0; # True if this is the child process.
118:
119: #
120: # The hash below gives the HTML format for log messages
121: # given a severity.
122: #
123: my %LogFormats;
124:
125: $LogFormats{"CRITICAL"} = "<font color='red'>CRITICAL: %s</font>";
126: $LogFormats{"SUCCESS"} = "<font color='green'>SUCCESS: %s</font>";
127: $LogFormats{"INFO"} = "<font color='yellow'>INFO: %s</font>";
128: $LogFormats{"WARNING"} = "<font color='blue'>WARNING: %s</font>";
129: $LogFormats{"DEFAULT"} = " %s ";
130:
131:
132: # UpdateStatus;
133: # Update the idle status display to show how many connections
134: # are left, retries and other stuff.
135: #
136: sub UpdateStatus {
137: if ($ConnectionRetriesLeft > 0) {
138: ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
139: ." Retries remaining: ".$ConnectionRetriesLeft
140: ." ($KeyMode)");
141: } else {
142: ShowStatus(GetServerHost()." >> DEAD <<");
143: }
144: }
145:
146:
147: =pod
148:
149: =head2 LogPerm
150:
151: Makes an entry into the permanent log file.
152:
153: =cut
154:
155: sub LogPerm {
156: my $message=shift;
157: my $execdir=$perlvar{'lonDaemons'};
158: my $now=time;
159: my $local=localtime($now);
160: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
161: chomp($message);
162: print $fh "$now:$message:$local\n";
163: }
164:
165: =pod
166:
167: =head2 Log
168:
169: Logs a message to the log file.
170: Parameters:
171:
172: =item severity
173:
174: One of CRITICAL, WARNING, INFO, SUCCESS used to select the
175: format string used to format the message. if the severity is
176: not a defined severity the Default format string is used.
177:
178: =item message
179:
180: The base message. In addtion to the format string, the message
181: will be appended to a string containing the name of our remote
182: host and the time will be formatted into the message.
183:
184: =cut
185:
186: sub Log {
187:
188: my ($severity, $message) = @_;
189:
190: if(!$LogFormats{$severity}) {
191: $severity = "DEFAULT";
192: }
193:
194: my $format = $LogFormats{$severity};
195:
196: # Put the window dressing in in front of the message format:
197:
198: my $now = time;
199: my $local = localtime($now);
200: my $finalformat = "$local ($$) [$RemoteHost] [$Status] ";
201: $finalformat = $finalformat.$format."\n";
202:
203: # open the file and put the result.
204:
205: my $execdir = $perlvar{'lonDaemons'};
206: my $fh = IO::File->new(">>$execdir/logs/lonc.log");
207: my $msg = sprintf($finalformat, $message);
208: $RecentLogEntry = $msg;
209: print $fh $msg;
210:
211:
212: }
213:
214:
215: =pod
216:
217: =head2 GetPeerName
218:
219: Returns the name of the host that a socket object is connected to.
220:
221: =cut
222:
223: sub GetPeername {
224:
225:
226: my ($connection, $AdrFamily) = @_;
227:
228: my $peer = $connection->peername();
229: my $peerport;
230: my $peerip;
231: if($AdrFamily == AF_INET) {
232: ($peerport, $peerip) = sockaddr_in($peer);
233: my $peername = gethostbyaddr($peerip, $AdrFamily);
234: return $peername;
235: } elsif ($AdrFamily == AF_UNIX) {
236: my $peerfile;
237: ($peerfile) = sockaddr_un($peer);
238: return $peerfile;
239: }
240: }
241: =pod
242:
243: =head2 Debug
244:
245: Invoked to issue a debug message.
246:
247: =cut
248:
249: sub Debug {
250:
251: my ($level, $message) = @_;
252:
253: if ($level <= $DebugLevel) {
254: Log("INFO", "-Debug- $message host = $RemoteHost");
255: }
256: }
257:
258: sub SocketDump {
259:
260: my ($level, $socket) = @_;
261:
262: if($level <= $DebugLevel) {
263: $socket->Dump(-1); # Ensure it will get dumped.
264: }
265: }
266:
267: =pod
268:
269: =head2 ShowStatus
270:
271: Place some text as our pid status.
272: and as what we return in a SIGUSR1
273:
274: =cut
275:
276: sub ShowStatus {
277: my $state = shift;
278: my $now = time;
279: my $local = localtime($now);
280: $Status = $local.": ".$state;
281: $0='lonc: '.$state.' '.$local;
282: }
283:
284: =pod
285:
286: =head2 SocketTimeout
287:
288: Called when an action on the socket times out. The socket is
289: destroyed and any active transaction is failed.
290:
291:
292: =cut
293:
294: sub SocketTimeout {
295: my $Socket = shift;
296: Log("WARNING", "A socket timeout was detected");
297: Debug(5, " SocketTimeout called: ");
298: $Socket->Dump(0);
299: if(exists($ActiveTransactions{$Socket})) {
300: FailTransaction($ActiveTransactions{$Socket});
301: }
302: KillSocket($Socket); # A transaction timeout also counts as
303: # a connection failure:
304: $ConnectionRetriesLeft--;
305: if($ConnectionRetriesLeft <= 0) {
306: Log("CRITICAL", "Host marked DEAD: ".GetServerHost());
307: $LondConnecting = 0;
308: }
309:
310: }
311:
312: #
313: # This function should be called by the child in all cases where it must
314: # exit. The child process must create a lock file for the AF_UNIX socket
315: # in order to prevent connection requests from lonnet in the time between
316: # process exit and the parent picking up the listen again.
317: #
318: # Parameters:
319: # exit_code - Exit status value, however see the next parameter.
320: # message - If this optional parameter is supplied, the exit
321: # is via a die with this message.
322: #
323: sub child_exit {
324: my ($exit_code, $message) = @_;
325:
326: # Regardless of how we exit, we may need to do the lock thing:
327:
328: #
329: # Create a lock file since there will be a time window
330: # between our exit and the parent's picking up the listen
331: # during which no listens will be done on the
332: # lonnet client socket.
333: #
334: my $lock_file = &GetLoncSocketPath().".lock";
335: open(LOCK,">$lock_file");
336: print LOCK "Contents not important";
337: close(LOCK);
338: unlink(&GetLoncSocketPath());
339:
340: if ($message) {
341: die($message);
342: } else {
343: exit($exit_code);
344: }
345: }
346: #----------------------------- Timer management ------------------------
347:
348: =pod
349:
350: =head2 Tick
351:
352: Invoked each timer tick.
353:
354: =cut
355:
356:
357: sub Tick {
358: my ($Event) = @_;
359: my $clock_watcher = $Event->w;
360:
361: my $client;
362: UpdateStatus();
363:
364: # Is it time to prune connection count:
365:
366:
367: if($IdleConnections->Count() &&
368: ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
369: $IdleSeconds++;
370: if($IdleSeconds > $IdleTimeout) { # Prune a connection...
371: my $Socket = $IdleConnections->pop();
372: KillSocket($Socket);
373: $IdleSeconds = 0; # Otherwise all connections get trimmed to fast.
374: UpdateStatus();
375: if(($ConnectionCount == 0)) {
376: &child_exit(0);
377:
378: }
379: }
380: } else {
381: $IdleSeconds = 0; # Reset idle count if not idle.
382: }
383: #
384: # For each inflight transaction, tick down its timeout counter.
385: #
386:
387: foreach my $item (keys %ActiveConnections) {
388: my $State = $ActiveConnections{$item}->data->GetState();
389: if ($State ne 'Idle') {
390: Debug(5,"Ticking Socket $State $item");
391: $ActiveConnections{$item}->data->Tick();
392: }
393: }
394: # Do we have work in the queue, but no connections to service them?
395: # If so, try to make some new connections to get things going again.
396: #
397: # Note this code is dead now...
398: #
399: my $Requests = $WorkQueue->Count();
400: if (($ConnectionCount == 0) && ($Requests > 0) && (!$LondConnecting)) {
401: if ($ConnectionRetriesLeft > 0) {
402: Debug(5,"Work but no connections, Make a new one");
403: my $success;
404: $success = &MakeLondConnection;
405: if($success == 0) { # All connections failed:
406: Debug(5,"Work in queue failed to make any connectiouns\n");
407: EmptyQueue(); # Fail pending transactions with con_lost.
408: CloseAllLondConnections(); # Should all be closed but....
409: }
410: } else {
411: $LondConnecting = 0;
412: ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
413: Debug(5,"Work in queue, but gave up on connections..flushing\n");
414: EmptyQueue(); # Connections can't be established.
415: CloseAllLondConnections(); # Should all already be closed but...
416: }
417:
418: }
419: if ($ConnectionCount == 0) {
420: $KeyMode = "";
421: $clock_watcher->cancel();
422: }
423: &UpdateStatus();
424: }
425:
426: =pod
427:
428: =head2 SetupTimer
429:
430: Sets up a 1 per sec recurring timer event. The event handler is used to:
431:
432: =item
433:
434: Trigger timeouts on communications along active sockets.
435:
436: =item
437:
438: Trigger disconnections of idle sockets.
439:
440: =cut
441:
442: sub SetupTimer {
443: Debug(6, "SetupTimer");
444: Event->timer(interval => 1, cb => \&Tick,
445: hard => 1);
446: }
447:
448: =pod
449:
450: =head2 ServerToIdle
451:
452: This function is called when a connection to the server is
453: ready for more work.
454:
455: If there is work in the Work queue the top element is dequeued
456: and the connection will start to work on it. If the work queue is
457: empty, the connection is pushed on the idle connection stack where
458: it will either get another work unit, or alternatively, if it sits there
459: long enough, it will be shut down and released.
460:
461: =cut
462:
463: sub ServerToIdle {
464: my $Socket = shift; # Get the socket.
465: $KeyMode = $Socket->{AuthenticationMode};
466: delete($ActiveTransactions{$Socket}); # Server has no transaction
467:
468: &Debug(5, "Server to idle");
469:
470: # If there's work to do, start the transaction:
471:
472: my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
473: if ($reqdata ne undef) {
474: Debug(5, "Queue gave request data: ".$reqdata->getRequest());
475: &StartRequest($Socket, $reqdata);
476:
477: } else {
478:
479: # There's no work waiting, so push the server to idle list.
480: &Debug(5, "No new work requests, server connection going idle");
481: $IdleConnections->push($Socket);
482: }
483: }
484:
485: =pod
486:
487: =head2 ClientWritable
488:
489: Event callback for when a client socket is writable.
490:
491: This callback is established when a transaction reponse is
492: avaiable from lond. The response is forwarded to the unix socket
493: as it becomes writable in this sub.
494:
495: Parameters:
496:
497: =item Event
498:
499: The event that has been triggered. Event->w->data is
500: the data and Event->w->fd is the socket to write.
501:
502: =cut
503:
504: sub ClientWritable {
505: my $Event = shift;
506: my $Watcher = $Event->w;
507: if (!defined($Watcher)) {
508: &child_exit(-1,'No watcher for event in ClientWritable');
509: }
510: my $Data = $Watcher->data;
511: my $Socket = $Watcher->fd;
512:
513: # Try to send the data:
514:
515: &Debug(6, "ClientWritable writing".$Data);
516: &Debug(9, "Socket is: ".$Socket);
517:
518: if($Socket->connected) {
519: my $result = $Socket->send($Data, 0);
520:
521: # $result undefined: the write failed.
522: # otherwise $result is the number of bytes written.
523: # Remove that preceding string from the data.
524: # If the resulting data is empty, destroy the watcher
525: # and set up a read event handler to accept the next
526: # request.
527:
528: &Debug(9,"Send result is ".$result." Defined: ".defined($result));
529: if($result ne undef) {
530: &Debug(9, "send result was defined");
531: if($result == length($Data)) { # Entire string sent.
532: &Debug(9, "ClientWritable data all written");
533: $Watcher->cancel();
534: #
535: # Set up to read next request from socket:
536:
537: my $descr = sprintf("Connection to lonc client %d",
538: $ActiveClients{$Socket});
539: Event->io(cb => \&ClientRequest,
540: poll => 'r',
541: desc => $descr,
542: data => "",
543: fd => $Socket);
544:
545: } else { # Partial string sent.
546: $Watcher->data(substr($Data, $result));
547: if($result == 0) { # client hung up on us!!
548: # Log("INFO", "lonc pipe client hung up on us!");
549: $Watcher->cancel;
550: $Socket->shutdown(2);
551: $Socket->close();
552: }
553: }
554:
555: } else { # Error of some sort...
556:
557: # Some errnos are possible:
558: my $errno = $!;
559: if($errno == POSIX::EWOULDBLOCK ||
560: $errno == POSIX::EAGAIN ||
561: $errno == POSIX::EINTR) {
562: # No action taken?
563: } else { # Unanticipated errno.
564: &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
565: $Watcher->cancel; # Stop the watcher.
566: $Socket->shutdown(2); # Kill connection
567: $Socket->close(); # Close the socket.
568: }
569:
570: }
571: } else {
572: $Watcher->cancel(); # A delayed request...just cancel.
573: return;
574: }
575: }
576:
577: =pod
578:
579: =head2 CompleteTransaction
580:
581: Called when the reply data has been received for a lond
582: transaction. The reply data must now be sent to the
583: ultimate client on the other end of the Unix socket. This is
584: done by setting up a writable event for the socket with the
585: data the reply data.
586:
587: Parameters:
588:
589: =item Socket
590:
591: Socket on which the lond transaction occured. This is a
592: LondConnection. The data received is in the TransactionReply member.
593:
594: =item Transaction
595:
596: The transaction that is being completed.
597:
598: =cut
599:
600: sub CompleteTransaction {
601: &Debug(5,"Complete transaction");
602:
603: my ($Socket, $Transaction) = @_;
604:
605: if (!$Transaction->isDeferred()) { # Normal transaction
606: my $data = $Socket->GetReply(); # Data to send.
607: if($LogTransactions) {
608: Log("SUCCESS", "Reply from lond: '$data'");
609: }
610: StartClientReply($Transaction, $data);
611: } else { # Delete deferred transaction file.
612: Log("SUCCESS", "A delayed transaction was completed");
613: LogPerm("S:".$Transaction->getClient().":".$Transaction->getRequest());
614: unlink($Transaction->getFile());
615: }
616: }
617:
618: =pod
619:
620: =head1 StartClientReply
621:
622: Initiates a reply to a client where the reply data is a parameter.
623:
624: =head2 parameters:
625:
626: =item Transaction
627:
628: The transaction for which we are responding to the client.
629:
630: =item data
631:
632: The data to send to apached client.
633:
634: =cut
635:
636: sub StartClientReply {
637:
638: my ($Transaction, $data) = @_;
639:
640: my $Client = $Transaction->getClient();
641:
642: &Debug(8," Reply was: ".$data);
643: my $Serial = $ActiveClients{$Client};
644: my $desc = sprintf("Connection to lonc client %d",
645: $Serial);
646: Event->io(fd => $Client,
647: poll => "w",
648: desc => $desc,
649: cb => \&ClientWritable,
650: data => $data);
651: }
652:
653: =pod
654:
655: =head2 FailTransaction
656:
657: Finishes a transaction with failure because the associated lond socket
658: disconnected. There are two possibilities:
659: - The transaction is deferred: in which case we just quietly
660: delete the transaction since there is no client connection.
661: - The transaction is 'live' in which case we initiate the sending
662: of "con_lost" to the client.
663:
664: Deleting the transaction means killing it from the %ActiveTransactions hash.
665:
666: Parameters:
667:
668: =item client
669:
670: The LondTransaction we are failing.
671:
672:
673: =cut
674:
675: sub FailTransaction {
676: my $transaction = shift;
677:
678: # If the socket is dead, that's already logged.
679:
680: if ($ConnectionRetriesLeft > 0) {
681: Log("WARNING", "Failing transaction "
682: .$transaction->getLoggableRequest());
683: }
684: Debug(1, "Failing transaction: ".$transaction->getLoggableRequest());
685: if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
686: my $client = $transaction->getClient();
687: Debug(1," Replying con_lost to ".$transaction->getRequest());
688: StartClientReply($transaction, "con_lost\n");
689: }
690:
691: }
692:
693: =pod
694:
695: =head1 EmptyQueue
696:
697: Fails all items in the work queue with con_lost.
698: Note that each item in the work queue is a transaction.
699:
700: =cut
701:
702: sub EmptyQueue {
703: $ConnectionRetriesLeft--; # Counts as connection failure too.
704: while($WorkQueue->Count()) {
705: my $request = $WorkQueue->dequeue(); # This is a transaction
706: FailTransaction($request);
707: }
708: }
709:
710: =pod
711:
712: =head2 CloseAllLondConnections
713:
714: Close all connections open on lond prior to exit e.g.
715:
716: =cut
717:
718: sub CloseAllLondConnections {
719: foreach my $Socket (keys %ActiveConnections) {
720: if(exists($ActiveTransactions{$Socket})) {
721: FailTransaction($ActiveTransactions{$Socket});
722: }
723: KillSocket($Socket);
724: }
725: }
726:
727: =pod
728:
729: =head2 KillSocket
730:
731: Destroys a socket. This function can be called either when a socket
732: has died of 'natural' causes or because a socket needs to be pruned due to
733: idleness. If the socket has died naturally, if there are no longer any
734: live connections a new connection is created (in case there are transactions
735: in the queue). If the socket has been pruned, it is never re-created.
736:
737: Parameters:
738:
739: =item Socket
740:
741: The socket to kill off.
742:
743: =item Restart
744:
745: nonzero if we are allowed to create a new connection.
746:
747: =cut
748:
749: sub KillSocket {
750: my $Socket = shift;
751:
752: Log("WARNING", "Shutting down a socket");
753: $Socket->Shutdown();
754:
755: # If the socket came from the active connection set,
756: # delete its transaction... note that FailTransaction should
757: # already have been called!!!
758: # otherwise it came from the idle set.
759: #
760:
761: if(exists($ActiveTransactions{$Socket})) {
762: delete ($ActiveTransactions{$Socket});
763: }
764: if(exists($ActiveConnections{$Socket})) {
765: $ActiveConnections{$Socket}->cancel;
766: delete($ActiveConnections{$Socket});
767: $ConnectionCount--;
768: if ($ConnectionCount < 0) { $ConnectionCount = 0; }
769: }
770: # If the connection count has gone to zero and there is work in the
771: # work queue, the work all gets failed with con_lost.
772: #
773: if($ConnectionCount == 0) {
774: EmptyQueue();
775: CloseAllLondConnections; # Should all already be closed but...
776: }
777: UpdateStatus();
778: }
779:
780: =pod
781:
782: =head2 LondReadable
783:
784: This function is called whenever a lond connection
785: is readable. The action is state dependent:
786:
787: =head3 State=Initialized
788:
789: We''re waiting for the challenge, this is a no-op until the
790: state changes.
791:
792: =head3 State=Challenged
793:
794: The challenge has arrived we need to transition to Writable.
795: The connection must echo the challenge back.
796:
797: =head3 State=ChallengeReplied
798:
799: The challenge has been replied to. The we are receiveing the
800: 'ok' from the partner.
801:
802: =head3 State=ReadingVersionString
803:
804: We have requested the lond version and are reading the
805: version back. Upon completion, we'll store the version away
806: for future use(?).
807:
808: =head3 State=HostSet
809:
810: We have selected the domain name of our peer (multhomed hosts)
811: and are getting the reply (presumably ok) back.
812:
813: =head3 State=RequestingKey
814:
815: The ok has been received and we need to send the request for
816: an encryption key. Transition to writable for that.
817:
818: =head3 State=ReceivingKey
819:
820: The the key has been requested, now we are reading the new key.
821:
822: =head3 State=Idle
823:
824: The encryption key has been negotiated or we have finished
825: reading data from the a transaction. If the callback data has
826: a client as well as the socket iformation, then we are
827: doing a transaction and the data received is relayed to the client
828: before the socket is put on the idle list.
829:
830: =head3 State=SendingRequest
831:
832: I do not think this state can be received here, but if it is,
833: the appropriate thing to do is to transition to writable, and send
834: the request.
835:
836: =head3 State=ReceivingReply
837:
838: We finished sending the request to the server and now transition
839: to readable to receive the reply.
840:
841: The parameter to this function are:
842:
843: The event. Implicit in this is the watcher and its data. The data
844: contains at least the lond connection object and, if a
845: transaction is in progress, the socket attached to the local client.
846:
847: =cut
848:
849: sub LondReadable {
850:
851: my $Event = shift;
852: my $Watcher = $Event->w;
853: my $Socket = $Watcher->data;
854: my $client = undef;
855:
856: &Debug(6,"LondReadable called state = ".$Socket->GetState());
857:
858:
859: my $State = $Socket->GetState(); # All action depends on the state.
860:
861: SocketDump(6, $Socket);
862: my $status = $Socket->Readable();
863:
864: &Debug(2, "Socket->Readable returned: $status");
865:
866: if($status != 0) {
867: # bad return from socket read. Currently this means that
868: # The socket has become disconnected. We fail the transaction.
869:
870: Log("WARNING",
871: "Lond connection lost.");
872: if(exists($ActiveTransactions{$Socket})) {
873: FailTransaction($ActiveTransactions{$Socket});
874: } else {
875: # Socket is connecting and failed... need to mark
876: # no longer connecting.
877:
878: $LondConnecting = 0;
879: }
880: $Watcher->cancel();
881: KillSocket($Socket);
882: $ConnectionRetriesLeft--; # Counts as connection failure
883: return;
884: }
885: SocketDump(6,$Socket);
886:
887: $State = $Socket->GetState(); # Update in case of transition.
888: &Debug(6, "After read, state is ".$State);
889:
890: if($State eq "Initialized") {
891:
892:
893: } elsif ($State eq "ChallengeReceived") {
894: # The challenge must be echoed back; The state machine
895: # in the connection takes care of setting that up. Just
896: # need to transition to writable:
897:
898: $Watcher->cb(\&LondWritable);
899: $Watcher->poll("w");
900:
901: } elsif ($State eq "ChallengeReplied") {
902:
903: } elsif ($State eq "RequestingVersion") {
904: # Need to ask for the version... that is writiability:
905:
906: $Watcher->cb(\&LondWritable);
907: $Watcher->poll("w");
908:
909: } elsif ($State eq "ReadingVersionString") {
910: # Read the rest of the version string...
911: } elsif ($State eq "SetHost") {
912: # Need to request the actual domain get set...
913:
914: $Watcher->cb(\&LondWritable);
915: $Watcher->poll("w");
916: } elsif ($State eq "HostSet") {
917: # Reading the 'ok' from the peer.
918:
919: } elsif ($State eq "RequestingKey") {
920: # The ok was received. Now we need to request the key
921: # That requires us to be writable:
922:
923: $Watcher->cb(\&LondWritable);
924: $Watcher->poll("w");
925:
926: } elsif ($State eq "ReceivingKey") {
927:
928: } elsif ($State eq "Idle") {
929:
930: # This is as good a spot as any to get the peer version
931: # string:
932:
933: if($LondVersion eq "unknown") {
934: $LondVersion = $Socket->PeerVersion();
935: Log("INFO", "Connected to lond version: $LondVersion");
936: }
937: # If necessary, complete a transaction and then go into the
938: # idle queue.
939: # Note that a trasition to idle indicates a live lond
940: # on the other end so reset the connection retries.
941: #
942: $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
943: $Watcher->cancel();
944: if(exists($ActiveTransactions{$Socket})) {
945: Debug(5,"Completing transaction!!");
946: CompleteTransaction($Socket,
947: $ActiveTransactions{$Socket});
948: } else {
949: Log("SUCCESS", "Connection ".$ConnectionCount." to "
950: .$RemoteHost." now ready for action");
951: }
952: ServerToIdle($Socket); # Next work unit or idle.
953:
954: #
955: $LondConnecting = 0; # Best spot I can think of for this.
956: #
957:
958: } elsif ($State eq "SendingRequest") {
959: # We need to be writable for this and probably don't belong
960: # here inthe first place.
961:
962: Debug(6, "SendingRequest state encountered in readable");
963: $Watcher->poll("w");
964: $Watcher->cb(\&LondWritable);
965:
966: } elsif ($State eq "ReceivingReply") {
967:
968:
969: } else {
970: # Invalid state.
971: Debug(4, "Invalid state in LondReadable");
972: }
973: }
974:
975: =pod
976:
977: =head2 LondWritable
978:
979: This function is called whenever a lond connection
980: becomes writable while there is a writeable monitoring
981: event. The action taken is very state dependent:
982:
983: =head3 State = Connected
984:
985: The connection is in the process of sending the 'init' hailing to the
986: lond on the remote end. The connection object''s Writable member is
987: called. On error, ConnectionError is called to destroy the connection
988: and remove it from the ActiveConnections hash
989:
990: =head3 Initialized
991:
992: 'init' has been sent, writability monitoring is removed and
993: readability monitoring is started with LondReadable as the callback.
994:
995: =head3 ChallengeReceived
996:
997: The connection has received the who are you challenge from the remote
998: system, and is in the process of sending the challenge
999: response. Writable is called.
1000:
1001: =head3 ChallengeReplied
1002:
1003: The connection has replied to the initial challenge The we switch to
1004: monitoring readability looking for the server to reply with 'ok'.
1005:
1006: =head3 RequestingKey
1007:
1008: The connection is in the process of requesting its encryption key.
1009: Writable is called.
1010:
1011: =head3 ReceivingKey
1012:
1013: The connection has sent the request for a key. Switch to readability
1014: monitoring to accept the key
1015:
1016: =head3 SendingRequest
1017:
1018: The connection is in the process of sending a request to the server.
1019: This request is part of a client transaction. All the states until
1020: now represent the client setup protocol. Writable is called.
1021:
1022: =head3 ReceivingReply
1023:
1024: The connection has sent a request. Now it must receive a reply.
1025: Readability monitoring is requested.
1026:
1027: This function is an event handler and therefore receives as
1028: a parameter the event that has fired. The data for the watcher
1029: of this event is a reference to a list of one or two elements,
1030: depending on state. The first (and possibly only) element is the
1031: socket. The second (present only if a request is in progress)
1032: is the socket on which to return a reply to the caller.
1033:
1034: =cut
1035:
1036: sub LondWritable {
1037: my $Event = shift;
1038: my $Watcher = $Event->w;
1039: my $Socket = $Watcher->data;
1040: my $State = $Socket->GetState();
1041:
1042: Debug(6,"LondWritable State = ".$State."\n");
1043:
1044:
1045: # Figure out what to do depending on the state of the socket:
1046:
1047:
1048:
1049:
1050: SocketDump(6,$Socket);
1051:
1052: # If the socket is writable, we must always write.
1053: # Only by writing will we undergo state transitions.
1054: # Old logic wrote in state specific code below, however
1055: # That forces us at least through another invocation of
1056: # this function after writability is possible again.
1057: # This logic also factors out common code for handling
1058: # write failures... in all cases, write failures
1059: # Kill the socket.
1060: # This logic makes the branches of the >big< if below
1061: # so that the writing states are actually NO-OPs.
1062:
1063: if ($Socket->Writable() != 0) {
1064: # The write resulted in an error.
1065: # We'll treat this as if the socket got disconnected:
1066: Log("WARNING", "Connection to ".$RemoteHost.
1067: " has been disconnected");
1068: if(exists($ActiveTransactions{$Socket})) {
1069: FailTransaction($ActiveTransactions{$Socket});
1070: } else {
1071: # In the process of conneting, so need to turn that off.
1072:
1073: $LondConnecting = 0;
1074: }
1075: $Watcher->cancel();
1076: KillSocket($Socket);
1077: return;
1078: }
1079:
1080:
1081:
1082: if ($State eq "Connected") {
1083:
1084: # "init" is being sent...
1085:
1086: } elsif ($State eq "Initialized") {
1087:
1088: # Now that init was sent, we switch
1089: # to watching for readability:
1090:
1091: $Watcher->cb(\&LondReadable);
1092: $Watcher->poll("r");
1093:
1094: } elsif ($State eq "ChallengeReceived") {
1095: # We received the challenge, now we
1096: # are echoing it back. This is a no-op,
1097: # we're waiting for the state to change
1098:
1099: } elsif ($State eq "ChallengeReplied") {
1100: # The echo was sent back, so we switch
1101: # to watching readability.
1102:
1103: $Watcher->cb(\&LondReadable);
1104: $Watcher->poll("r");
1105: } elsif ($State eq "RequestingVersion") {
1106: # Sending the peer a version request...
1107:
1108: } elsif ($State eq "ReadingVersionString") {
1109: # Transition to read since we have sent the
1110: # version command and now just need to read the
1111: # version string from the peer:
1112:
1113: $Watcher->cb(\&LondReadable);
1114: $Watcher->poll("r");
1115:
1116: } elsif ($State eq "SetHost") {
1117: # Setting the remote domain...
1118:
1119: } elsif ($State eq "HostSet") {
1120: # Back to readable to get the ok.
1121:
1122: $Watcher->cb(\&LondReadable);
1123: $Watcher->poll("r");
1124:
1125:
1126: } elsif ($State eq "RequestingKey") {
1127: # At this time we're requesting the key.
1128: # again, this is essentially a no-op.
1129:
1130: } elsif ($State eq "ReceivingKey") {
1131: # Now we need to wait for the key
1132: # to come back from the peer:
1133:
1134: $Watcher->cb(\&LondReadable);
1135: $Watcher->poll("r");
1136:
1137: } elsif ($State eq "SendingRequest") {
1138:
1139: # At this time we are sending a request to the
1140: # peer... write the next chunk:
1141:
1142:
1143: } elsif ($State eq "ReceivingReply") {
1144: # The send has completed. Wait for the
1145: # data to come in for a reply.
1146: Debug(8,"Writable sent request/receiving reply");
1147: $Watcher->cb(\&LondReadable);
1148: $Watcher->poll("r");
1149:
1150: } else {
1151: # Control only passes here on an error:
1152: # the socket state does not match any
1153: # of the known states... so an error
1154: # must be logged.
1155:
1156: &Debug(4, "Invalid socket state ".$State."\n");
1157: }
1158:
1159: }
1160:
1161: =pod
1162:
1163: =cut
1164:
1165:
1166: sub QueueDelayed {
1167: Debug(3,"QueueDelayed called");
1168:
1169: my $path = "$perlvar{'lonSockDir'}/delayed";
1170:
1171: Debug(4, "Delayed path: ".$path);
1172: opendir(DIRHANDLE, $path);
1173:
1174: my $host_id_re = '(?:'.join('|',map {quotemeta($_)} (@all_host_ids)).')';
1175: my @alldelayed = grep(/\.$host_id_re$/, readdir(DIRHANDLE));
1176: closedir(DIRHANDLE);
1177: foreach my $dfname (sort(@alldelayed)) {
1178: my $reqfile = "$path/$dfname";
1179: my ($host_id) = ($dfname =~ /\.([^.]*)$/);
1180: Debug(4, "queueing ".$reqfile." for $host_id");
1181: my $Handle = IO::File->new($reqfile);
1182: my $cmd = <$Handle>;
1183: chomp $cmd; # There may or may not be a newline...
1184: $cmd = $cmd."\n"; # now for sure there's exactly one newline.
1185: my $Transaction = LondTransaction->new("sethost:$host_id:$cmd");
1186: $Transaction->SetDeferred($reqfile);
1187: QueueTransaction($Transaction);
1188: }
1189:
1190: }
1191:
1192: =pod
1193:
1194: =head2 MakeLondConnection
1195:
1196: Create a new lond connection object, and start it towards its initial
1197: idleness. Once idle, it becomes elligible to receive transactions
1198: from the work queue. If the work queue is not empty when the
1199: connection is completed and becomes idle, it will dequeue an entry and
1200: start off on it.
1201:
1202: =cut
1203:
1204: sub MakeLondConnection {
1205: Debug(4,"MakeLondConnection to ".GetServerHost()." on port "
1206: .GetServerPort());
1207:
1208: my $Connection = LondConnection->new(&GetServerHost(),
1209: &GetServerPort(),
1210: &GetHostId());
1211:
1212: if($Connection eq undef) {
1213: Log("CRITICAL","Failed to make a connection with lond.");
1214: $ConnectionRetriesLeft--;
1215: return 0; # Failure.
1216: } else {
1217:
1218: $LondConnecting = 1; # Connection in progress.
1219: # The connection needs to have writability
1220: # monitored in order to send the init sequence
1221: # that starts the whole authentication/key
1222: # exchange underway.
1223: #
1224: my $Socket = $Connection->GetSocket();
1225: if($Socket eq undef) {
1226: &child_exit(-1, "did not get a socket from the connection");
1227: } else {
1228: &Debug(9,"MakeLondConnection got socket: ".$Socket);
1229: }
1230:
1231: $Connection->SetTimeoutCallback(\&SocketTimeout);
1232:
1233: my $event = Event->io(fd => $Socket,
1234: poll => 'w',
1235: cb => \&LondWritable,
1236: data => $Connection,
1237: desc => 'Connection to lond server');
1238: $ActiveConnections{$Connection} = $event;
1239: if ($ConnectionCount == 0) {
1240: &SetupTimer; # Need to handle timeouts with connections...
1241: }
1242: $ConnectionCount++;
1243: Debug(4, "Connection count = ".$ConnectionCount);
1244: if($ConnectionCount == 1) { # First Connection:
1245: QueueDelayed;
1246: }
1247: Log("SUCESS", "Created connection ".$ConnectionCount
1248: ." to host ".GetServerHost());
1249: return 1; # Return success.
1250: }
1251:
1252: }
1253:
1254: =pod
1255:
1256: =head2 StartRequest
1257:
1258: Starts a lond request going on a specified lond connection.
1259: parameters are:
1260:
1261: =item $Lond
1262:
1263: Connection to the lond that will send the transaction and receive the
1264: reply.
1265:
1266: =item $Client
1267:
1268: Connection to the client that is making this request We got the
1269: request from this socket, and when the request has been relayed to
1270: lond and we get a reply back from lond it will get sent to this
1271: socket.
1272:
1273: =item $Request
1274:
1275: The text of the request to send.
1276:
1277: =cut
1278:
1279: sub StartRequest {
1280:
1281: my ($Lond, $Request) = @_;
1282:
1283: Debug(6, "StartRequest: ".$Request->getRequest());
1284:
1285: my $Socket = $Lond->GetSocket();
1286:
1287: $Request->Activate($Lond);
1288: $ActiveTransactions{$Lond} = $Request;
1289:
1290: $Lond->InitiateTransaction($Request->getRequest());
1291: my $event = Event->io(fd => $Socket,
1292: poll => "w",
1293: cb => \&LondWritable,
1294: data => $Lond,
1295: desc => "lond transaction connection");
1296: $ActiveConnections{$Lond} = $event;
1297: Debug(8," Start Request made watcher data with ".$event->data."\n");
1298: }
1299:
1300: =pod
1301:
1302: =head2 QueueTransaction
1303:
1304: If there is an idle lond connection, it is put to work doing this
1305: transaction. Otherwise, the transaction is placed in the work queue.
1306: If placed in the work queue and the maximum number of connections has
1307: not yet been created, a new connection will be started. Our goal is
1308: to eventually have a sufficient number of connections that the work
1309: queue will typically be empty. parameters are:
1310:
1311: =item Socket
1312:
1313: open on the lonc client.
1314:
1315: =item Request
1316:
1317: data to send to the lond.
1318:
1319: =cut
1320:
1321: sub QueueTransaction {
1322:
1323: my $requestData = shift; # This is a LondTransaction.
1324: my $cmd = $requestData->getRequest();
1325:
1326: Debug(6,"QueueTransaction: ".$cmd);
1327:
1328: my $LondSocket = $IdleConnections->pop();
1329: if(!defined $LondSocket) { # Need to queue request.
1330: Debug(5,"Must queue...");
1331: $WorkQueue->enqueue($requestData);
1332: Debug(5, "Queue Transaction startnew $ConnectionCount $LondConnecting");
1333: if(($ConnectionCount < $MaxConnectionCount) && (! $LondConnecting)) {
1334:
1335: if($ConnectionRetriesLeft > 0) {
1336: Debug(5,"Starting additional lond connection");
1337: if(&MakeLondConnection() == 0) {
1338: EmptyQueue(); # Fail transactions, can't make connection.
1339: CloseAllLondConnections; # Should all be closed but...
1340: }
1341: } else {
1342: ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
1343: $LondConnecting = 0;
1344: EmptyQueue(); # It's worse than that ... he's dead Jim.
1345: CloseAllLondConnections; # Should all be closed but..
1346: }
1347: }
1348: } else { # Can start the request:
1349: Debug(8,"Can start...");
1350: StartRequest($LondSocket, $requestData);
1351: }
1352: }
1353:
1354: #-------------------------- Lonc UNIX socket handling ---------------------
1355:
1356: =pod
1357:
1358: =head2 ClientRequest
1359: Callback that is called when data can be read from the UNIX domain
1360: socket connecting us with an apache server process.
1361:
1362: =cut
1363:
1364: sub ClientRequest {
1365: Debug(6, "ClientRequest");
1366: my $event = shift;
1367: my $watcher = $event->w;
1368: my $socket = $watcher->fd;
1369: my $data = $watcher->data;
1370: my $thisread;
1371:
1372: Debug(9, " Watcher named: ".$watcher->desc);
1373:
1374: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1375: Debug(8, "rcv: data length = ".length($thisread)
1376: ." read =".$thisread);
1377: unless (defined $rv && length($thisread)) {
1378: # Likely eof on socket.
1379: Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
1380: close($socket);
1381: $watcher->cancel();
1382: delete($ActiveClients{$socket});
1383: return;
1384: }
1385: Debug(8,"Data: ".$data." this read: ".$thisread);
1386: $data = $data.$thisread; # Append new data.
1387: $watcher->data($data);
1388: if($data =~ /\n$/) { # Request entirely read.
1389: if ($data eq "close_connection_exit\n") {
1390: Log("CRITICAL",
1391: "Request Close Connection ... exiting");
1392: CloseAllLondConnections();
1393: exit;
1394: } elsif ($data eq "reset_retries\n") {
1395: Log("INFO", "Resetting Connection Retries.");
1396: $ConnectionRetriesLeft = $ConnectionRetries;
1397: &UpdateStatus();
1398: my $Transaction = LondTransaction->new($data);
1399: $Transaction->SetClient($socket);
1400: StartClientReply($Transaction, "ok\n");
1401: $watcher->cancel();
1402: return;
1403: }
1404: Debug(8, "Complete transaction received: ".$data);
1405: if ($LogTransactions) {
1406: Log("SUCCESS", "Transaction: '$data'"); # Transaction has \n.
1407: }
1408: my $Transaction = LondTransaction->new($data);
1409: $Transaction->SetClient($socket);
1410: QueueTransaction($Transaction);
1411: $watcher->cancel(); # Done looking for input data.
1412: }
1413:
1414: }
1415:
1416: #
1417: # Accept a connection request for a client (lonc child) and
1418: # start up an event watcher to keep an eye on input from that
1419: # Event. This can be called both from NewClient and from
1420: # ChildProcess.
1421: # Parameters:
1422: # $socket - The listener socket.
1423: # Returns:
1424: # NONE
1425: # Side Effects:
1426: # An event is made to watch the accepted connection.
1427: # Active clients hash is updated to reflect the new connection.
1428: # The client connection count is incremented.
1429: #
1430: sub accept_client {
1431: my ($socket) = @_;
1432:
1433: Debug(8, "Entering accept for lonc UNIX socket\n");
1434: my $connection = $socket->accept(); # Accept the client connection.
1435: Debug(8,"Connection request accepted from "
1436: .GetPeername($connection, AF_UNIX));
1437:
1438:
1439: my $description = sprintf("Connection to lonc client %d",
1440: $ClientConnection);
1441: Debug(9, "Creating event named: ".$description);
1442: Event->io(cb => \&ClientRequest,
1443: poll => 'r',
1444: desc => $description,
1445: data => "",
1446: fd => $connection);
1447: $ActiveClients{$connection} = $ClientConnection;
1448: $ClientConnection++;
1449: }
1450:
1451: =pod
1452:
1453: =head2 NewClient
1454:
1455: Callback that is called when a connection is received on the unix
1456: socket for a new client of lonc. The callback is parameterized by the
1457: event.. which is a-priori assumed to be an io event, and therefore has
1458: an fd member that is the Listener socket. We Accept the connection
1459: and register a new event on the readability of that socket:
1460:
1461: =cut
1462:
1463: sub NewClient {
1464: Debug(6, "NewClient");
1465: my $event = shift; # Get the event parameters.
1466: my $watcher = $event->w;
1467: my $socket = $watcher->fd; # Get the event' socket.
1468:
1469: &accept_client($socket);
1470: }
1471:
1472: =pod
1473:
1474: =head2 GetLoncSocketPath
1475:
1476: Returns the name of the UNIX socket on which to listen for client
1477: connections.
1478:
1479: =head2 Parameters:
1480:
1481: host (optional) - Name of the host socket to return.. defaults to
1482: the return from GetServerHost().
1483:
1484: =cut
1485:
1486: sub GetLoncSocketPath {
1487:
1488: my $host = GetServerHost(); # Default host.
1489: if (@_) {
1490: ($host) = @_; # Override if supplied.
1491: }
1492: return $UnixSocketDir."/".$host;
1493: }
1494:
1495: =pod
1496:
1497: =head2 GetServerHost
1498:
1499: Returns the host whose lond we talk with.
1500:
1501: =cut
1502:
1503: sub GetServerHost {
1504: return $RemoteHost; # Setup by the fork.
1505: }
1506:
1507: =pod
1508:
1509: =head2 GetServerId
1510:
1511: Returns the hostid whose lond we talk with.
1512:
1513: =cut
1514:
1515: sub GetHostId {
1516: return $RemoteHostId; # Setup by the fork.
1517: }
1518:
1519: =pod
1520:
1521: =head2 GetServerPort
1522:
1523: Returns the lond port number.
1524:
1525: =cut
1526:
1527: sub GetServerPort {
1528: return $perlvar{londPort};
1529: }
1530:
1531: =pod
1532:
1533: =head2 SetupLoncListener
1534:
1535: Setup a lonc listener event. The event is called when the socket
1536: becomes readable.. that corresponds to the receipt of a new
1537: connection. The event handler established will accept the connection
1538: (creating a communcations channel), that int turn will establish
1539: another event handler to subess requests.
1540:
1541: =head2 Parameters:
1542:
1543: host (optional) Name of the host to set up a unix socket to.
1544:
1545: =cut
1546:
1547: sub SetupLoncListener {
1548: my ($host,$SocketName) = @_;
1549: if (!$host) { $host = &GetServerHost(); }
1550: if (!$SocketName) { $SocketName = &GetLoncSocketPath($host); }
1551:
1552:
1553: unlink($SocketName);
1554:
1555: my $socket;
1556: unless ($socket =IO::Socket::UNIX->new(Local => $SocketName,
1557: Listen => 250,
1558: Type => SOCK_STREAM)) {
1559: if($I_am_child) {
1560: &child_exit(-1, "Failed to create a lonc listener socket");
1561: } else {
1562: die "Failed to create a lonc listner socket";
1563: }
1564: }
1565: return $socket;
1566: }
1567:
1568: #
1569: # Toggle transaction logging.
1570: # Implicit inputs:
1571: # LogTransactions
1572: # Implicit Outputs:
1573: # LogTransactions
1574: sub ToggleTransactionLogging {
1575: print STDERR "Toggle transaction logging...\n";
1576: if(!$LogTransactions) {
1577: $LogTransactions = 1;
1578: } else {
1579: $LogTransactions = 0;
1580: }
1581:
1582:
1583: Log("SUCCESS", "Toggled transaction logging: $LogTransactions \n");
1584: }
1585:
1586: =pod
1587:
1588: =head2 ChildStatus
1589:
1590: Child USR1 signal handler to report the most recent status
1591: into the status file.
1592:
1593: We also use this to reset the retries count in order to allow the
1594: client to retry connections with a previously dead server.
1595:
1596: =cut
1597:
1598: sub ChildStatus {
1599: my $event = shift;
1600: my $watcher = $event->w;
1601:
1602: Debug(2, "Reporting child status because : ".$watcher->data);
1603: my $docdir = $perlvar{'lonDocRoot'};
1604:
1605: open(LOG,">>$docdir/lon-status/loncstatus.txt");
1606: flock(LOG,LOCK_EX);
1607: print LOG $$."\t".$RemoteHost."\t".$Status."\t".
1608: $RecentLogEntry."\n";
1609: #
1610: # Write out information about each of the connections:
1611: #
1612: if ($DebugLevel > 2) {
1613: print LOG "Active connection statuses: \n";
1614: my $i = 1;
1615: print STDERR "================================= Socket Status Dump:\n";
1616: foreach my $item (keys %ActiveConnections) {
1617: my $Socket = $ActiveConnections{$item}->data;
1618: my $state = $Socket->GetState();
1619: print LOG "Connection $i State: $state\n";
1620: print STDERR "---------------------- Connection $i \n";
1621: $Socket->Dump(-1); # Ensure it gets dumped..
1622: $i++;
1623: }
1624: }
1625: flock(LOG,LOCK_UN);
1626: close(LOG);
1627: $ConnectionRetriesLeft = $ConnectionRetries;
1628: UpdateStatus();
1629: }
1630:
1631: =pod
1632:
1633: =head2 SignalledToDeath
1634:
1635: Called in response to a signal that causes a chid process to die.
1636:
1637: =cut
1638:
1639:
1640: sub SignalledToDeath {
1641: my $event = shift;
1642: my $watcher= $event->w;
1643:
1644: Debug(2,"Signalled to death! via ".$watcher->data);
1645: my ($signal) = $watcher->data;
1646: chomp($signal);
1647: Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "
1648: ."died through "."\"$signal\"");
1649: #LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
1650: # ."\"$signal\"");
1651: exit 0;
1652:
1653: }
1654:
1655: =pod
1656:
1657: =head2 ToggleDebug
1658:
1659: This sub toggles trace debugging on and off.
1660:
1661: =cut
1662:
1663: sub ToggleDebug {
1664: my $Current = $DebugLevel;
1665: $DebugLevel = $NextDebugLevel;
1666: $NextDebugLevel = $Current;
1667:
1668: Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
1669:
1670: }
1671:
1672: =pod
1673:
1674: =head2 ChildProcess
1675:
1676: This sub implements a child process for a single lonc daemon.
1677: Optional parameter:
1678: $socket - if provided, this is a socket already open for listen
1679: on the client socket. Otherwise, a new listen is set up.
1680:
1681: =cut
1682:
1683: sub ChildProcess {
1684: # We've inherited all the
1685: # events of our parent and those have to be cancelled or else
1686: # all holy bloody chaos will result.. trust me, I already made
1687: # >that< mistake.
1688:
1689: my $host = GetServerHost();
1690: foreach my $listener (keys %parent_dispatchers) {
1691: my $watcher = $parent_dispatchers{$listener};
1692: my $s = $watcher->fd;
1693: if ($listener ne $host) { # Close everyone but me.
1694: Debug(5, "Closing listen socket for $listener");
1695: $s->close();
1696: }
1697: Debug(5, "Killing watcher for $listener");
1698:
1699: $watcher->cancel();
1700: delete($parent_dispatchers{$listener});
1701:
1702: }
1703:
1704: # kill off the parent's signal handlers too!
1705: #
1706:
1707: for my $handler (keys %parent_handlers) {
1708: my $watcher = $parent_handlers{$handler};
1709: $watcher->cancel();
1710: delete($parent_handlers{$handler});
1711: }
1712:
1713: $I_am_child = 1; # Seems like in spite of it all I may still getting
1714: # parent event dispatches.. flag I'm a child.
1715:
1716:
1717: #
1718: # Signals must be handled by the Event framework...
1719: #
1720:
1721: Event->signal(signal => "QUIT",
1722: cb => \&SignalledToDeath,
1723: data => "QUIT");
1724: Event->signal(signal => "HUP",
1725: cb => \&ChildStatus,
1726: data => "HUP");
1727: Event->signal(signal => "USR1",
1728: cb => \&ChildStatus,
1729: data => "USR1");
1730: Event->signal(signal => "USR2",
1731: cb => \&ToggleTransactionLogging);
1732: Event->signal(signal => "INT",
1733: cb => \&ToggleDebug,
1734: data => "INT");
1735:
1736: # Figure out if we got passed a socket or need to open one to listen for
1737: # client requests.
1738:
1739: my ($socket) = @_;
1740: if (!$socket) {
1741:
1742: $socket = SetupLoncListener();
1743: }
1744: # Establish an event to listen for client connection requests.
1745:
1746:
1747: Event->io(cb => \&NewClient,
1748: poll => 'r',
1749: desc => 'Lonc Listener Unix Socket',
1750: fd => $socket);
1751:
1752: $Event::DebugLevel = $DebugLevel;
1753:
1754: Debug(9, "Making initial lond connection for ".$RemoteHost);
1755:
1756: # Setup the initial server connection:
1757:
1758: # &MakeLondConnection(); // let first work request do it.
1759:
1760: # need to accept the connection since the event may not fire.
1761:
1762: &accept_client($socket);
1763:
1764: Debug(9,"Entering event loop");
1765: my $ret = Event::loop(); # Start the main event loop.
1766:
1767:
1768: &child_exit (-1,"Main event loop exited!!!");
1769: }
1770:
1771: # Create a new child for host passed in:
1772:
1773: sub CreateChild {
1774: my ($host, $hostid) = @_;
1775:
1776: my $sigset = POSIX::SigSet->new(SIGINT);
1777: sigprocmask(SIG_BLOCK, $sigset);
1778: $RemoteHost = $host;
1779: ShowStatus('Parent keeping the flock'); # Update time in status message.
1780: Log("CRITICAL", "Forking server for ".$host);
1781: my $pid = fork;
1782: if($pid) { # Parent
1783: $RemoteHost = "Parent";
1784: $ChildPid{$pid} = $host;
1785: sigprocmask(SIG_UNBLOCK, $sigset);
1786: undef(@all_host_ids);
1787: } else { # child.
1788: $RemoteHostId = $hostid;
1789: ShowStatus("Connected to ".$RemoteHost);
1790: $SIG{INT} = 'DEFAULT';
1791: sigprocmask(SIG_UNBLOCK, $sigset);
1792: &ChildProcess(); # Does not return.
1793: }
1794: }
1795:
1796: # parent_client_connection:
1797: # Event handler that processes client connections for the parent process.
1798: # This sub is called when the parent is listening on a socket and
1799: # a connection request arrives. We must:
1800: # Start a child process to accept the connection request.
1801: # Kill our listen on the socket.
1802: # Parameter:
1803: # event - The event object that was created to monitor this socket.
1804: # event->w->fd is the socket.
1805: # Returns:
1806: # NONE
1807: #
1808: sub parent_client_connection {
1809: if ($I_am_child) {
1810: # Should not get here, but seem to anyway:
1811: &Debug(5," Child caught parent client connection event!!");
1812: my ($event) = @_;
1813: my $watcher = $event->w;
1814: $watcher->cancel(); # Try to kill it off again!!
1815: } else {
1816: &Debug(9, "parent_client_connection");
1817: my ($event) = @_;
1818: my $watcher = $event->w;
1819: my $socket = $watcher->fd;
1820: my $connection = $socket->accept(); # Accept the client connection.
1821: Event->io(cb => \&get_remote_hostname,
1822: poll => 'r',
1823: data => "",
1824: fd => $connection);
1825: }
1826: }
1827:
1828: sub get_remote_hostname {
1829: my ($event) = @_;
1830: my $watcher = $event->w;
1831: my $socket = $watcher->fd;
1832:
1833: my $thisread;
1834: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1835: Debug(8, "rcv: data length = ".length($thisread)." read =".$thisread);
1836: if (!defined($rv) || length($thisread) == 0) {
1837: # Likely eof on socket.
1838: Debug(5,"Client Socket closed on lonc for p_c_c");
1839: close($socket);
1840: $watcher->cancel();
1841: return;
1842: }
1843:
1844: my $data = $watcher->data().$thisread;
1845: $watcher->data($data);
1846: if($data =~ /\n$/) { # Request entirely read.
1847: chomp($data);
1848: } else {
1849: return;
1850: }
1851:
1852: &Debug(5,"Creating child for $data (parent_client_connection)");
1853: (my $hostname,my $lonid,@all_host_ids) = split(':',$data);
1854: $ChildHost{$hostname}++;
1855: if ($ChildHost{$hostname} == 1) {
1856: &CreateChild($hostname,$lonid);
1857: } else {
1858: &Log('WARNING',"Request for a second child on $hostname");
1859: }
1860: # Clean up the listen since now the child takes over until it exits.
1861: $watcher->cancel(); # Nolonger listening to this event
1862: $socket->send("done\n");
1863: $socket->close();
1864: }
1865:
1866: # parent_listen:
1867: # Opens a socket and starts a listen for the parent process on a client UNIX
1868: # domain socket.
1869: #
1870: # This involves:
1871: # Creating a socket for listen.
1872: # Removing any socket lock file
1873: # Adding an event handler for this socket becoming readable
1874: # To the parent's event dispatcher.
1875: # Parameters:
1876: # loncapa_host - LonCAPA cluster name of the host represented by the client
1877: # socket.
1878: # Returns:
1879: # NONE
1880: #
1881: sub parent_listen {
1882: my ($loncapa_host) = @_;
1883: Debug(5, "parent_listen: $loncapa_host");
1884:
1885: my ($socket,$file);
1886: if (!$loncapa_host) {
1887: $loncapa_host = 'common_parent';
1888: $file = $perlvar{'lonSockCreate'};
1889: } else {
1890: $file = &GetLoncSocketPath($loncapa_host);
1891: }
1892: $socket = &SetupLoncListener($loncapa_host,$file);
1893:
1894: $listening_to{$socket} = $loncapa_host;
1895: if (!$socket) {
1896: die "Unable to create a listen socket for $loncapa_host";
1897: }
1898:
1899: my $lock_file = $file.".lock";
1900: unlink($lock_file); # No problem if it doesn't exist yet [startup e.g.]
1901:
1902: my $watcher =
1903: Event->io(cb => \&parent_client_connection,
1904: poll => 'r',
1905: desc => "Parent listener unix socket ($loncapa_host)",
1906: data => "",
1907: fd => $socket);
1908: $parent_dispatchers{$loncapa_host} = $watcher;
1909:
1910: }
1911:
1912: sub parent_clean_up {
1913: my ($loncapa_host) = @_;
1914: Debug(1, "parent_clean_up: $loncapa_host");
1915:
1916: my $socket_file = &GetLoncSocketPath($loncapa_host);
1917: unlink($socket_file); # No problem if it doesn't exist yet [startup e.g.]
1918: my $lock_file = $socket_file.".lock";
1919: unlink($lock_file); # No problem if it doesn't exist yet [startup e.g.]
1920: }
1921:
1922:
1923:
1924: # This sub initiates a listen on the common unix domain lonc client socket.
1925: # loncnew starts up with no children, and only spawns off children when a
1926: # connection request occurs on the common client unix socket. The spawned
1927: # child continues to run until it has been idle a while at which point it
1928: # eventually exits and once more the parent picks up the listen.
1929: #
1930: # Parameters:
1931: # NONE
1932: # Implicit Inputs:
1933: # The configuration file that has been read in by LondConnection.
1934: # Returns:
1935: # NONE
1936: #
1937: sub listen_on_common_socket {
1938: Debug(5, "listen_on_common_socket");
1939: &parent_listen();
1940: }
1941:
1942: # server_died is called whenever a child process exits.
1943: # Since this is dispatched via a signal, we must process all
1944: # dead children until there are no more left. The action
1945: # is to:
1946: # - Remove the child from the bookeeping hashes
1947: # - Re-establish a listen on the unix domain socket associated
1948: # with that host.
1949: # Parameters:
1950: # The event, but we don't actually care about it.
1951: sub server_died {
1952: &Debug(9, "server_died called...");
1953:
1954: while(1) { # Loop until waitpid nowait fails.
1955: my $pid = waitpid(-1, WNOHANG);
1956: if($pid <= 0) {
1957: return; # Nothing left to wait for.
1958: }
1959: # need the host to restart:
1960:
1961: my $host = $ChildPid{$pid};
1962: if($host) { # It's for real...
1963: &Debug(9, "Caught sigchild for $host");
1964: delete($ChildPid{$pid});
1965: delete($ChildHost{$host});
1966: &parent_clean_up($host);
1967:
1968: } else {
1969: &Debug(5, "Caught sigchild for pid not in hosts hash: $pid");
1970: }
1971: }
1972:
1973: }
1974:
1975: #
1976: # Parent process logic pass 1:
1977: # For each entry in the hosts table, we will
1978: # fork off an instance of ChildProcess to service the transactions
1979: # to that host. Each pid will be entered in a global hash
1980: # with the value of the key, the host.
1981: # The parent will then enter a loop to wait for process exits.
1982: # Each exit gets logged and the child gets restarted.
1983: #
1984:
1985: #
1986: # Fork and start in new session so hang-up isn't going to
1987: # happen without intent.
1988: #
1989:
1990:
1991:
1992:
1993:
1994:
1995: ShowStatus("Forming new session");
1996: my $childpid = fork;
1997: if ($childpid != 0) {
1998: sleep 4; # Give child a chacne to break to
1999: exit 0; # a new sesion.
2000: }
2001: #
2002: # Write my pid into the pid file so I can be located
2003: #
2004:
2005: ShowStatus("Parent writing pid file:");
2006: my $execdir = $perlvar{'lonDaemons'};
2007: open (PIDSAVE, ">$execdir/logs/lonc.pid");
2008: print PIDSAVE "$$\n";
2009: close(PIDSAVE);
2010:
2011:
2012:
2013: if (POSIX::setsid() < 0) {
2014: print "Could not create new session\n";
2015: exit -1;
2016: }
2017:
2018: ShowStatus("Forking node servers");
2019:
2020: Log("CRITICAL", "--------------- Starting children ---------------");
2021:
2022: LondConnection::ReadConfig; # Read standard config files.
2023:
2024: $RemoteHost = "[parent]";
2025: &listen_on_common_socket();
2026:
2027: $RemoteHost = "Parent Server";
2028:
2029: # Maintain the population:
2030:
2031: ShowStatus("Parent keeping the flock");
2032:
2033:
2034: # We need to setup a SIGChild event to handle the exit (natural or otherwise)
2035: # of the children.
2036:
2037: Event->signal(cb => \&server_died,
2038: desc => "Child exit handler",
2039: signal => "CHLD");
2040:
2041:
2042: # Set up all the other signals we set up.
2043:
2044: $parent_handlers{INT} = Event->signal(cb => \&Terminate,
2045: desc => "Parent INT handler",
2046: signal => "INT");
2047: $parent_handlers{TERM} = Event->signal(cb => \&Terminate,
2048: desc => "Parent TERM handler",
2049: signal => "TERM");
2050: $parent_handlers{HUP} = Event->signal(cb => \&KillThemAll,
2051: desc => "Parent HUP handler.",
2052: signal => "HUP");
2053: $parent_handlers{USR1} = Event->signal(cb => \&CheckKids,
2054: desc => "Parent USR1 handler",
2055: signal => "USR1");
2056: $parent_handlers{USR2} = Event->signal(cb => \&UpdateKids,
2057: desc => "Parent USR2 handler.",
2058: signal => "USR2");
2059:
2060: # Start procdesing events.
2061:
2062: $Event::DebugLevel = $DebugLevel;
2063: Debug(9, "Parent entering event loop");
2064: my $ret = Event::loop();
2065: die "Main Event loop exited: $ret";
2066:
2067: =pod
2068:
2069: =head1 CheckKids
2070:
2071: Since kids do not die as easily in this implementation
2072: as the previous one, there is no need to restart the
2073: dead ones (all dead kids get restarted when they die!!)
2074: The only thing this function does is to pass USR1 to the
2075: kids so that they report their status.
2076:
2077: =cut
2078:
2079: sub CheckKids {
2080: Debug(2, "Checking status of children");
2081: my $docdir = $perlvar{'lonDocRoot'};
2082: my $fh = IO::File->new(">$docdir/lon-status/loncstatus.txt");
2083: my $now=time;
2084: my $local=localtime($now);
2085: print $fh "LONC status $local - parent $$ \n\n";
2086: foreach my $host (keys %parent_dispatchers) {
2087: print $fh "LONC Parent process listening for $host\n";
2088: }
2089: foreach my $pid (keys %ChildPid) {
2090: Debug(2, "Sending USR1 -> $pid");
2091: kill 'USR1' => $pid; # Tell Child to report status.
2092: }
2093:
2094: }
2095:
2096: =pod
2097:
2098: =head1 UpdateKids
2099:
2100: parent's SIGUSR2 handler. This handler:
2101:
2102: =item
2103:
2104: Rereads the hosts file.
2105:
2106: =item
2107:
2108: Kills off (via sigint) children for hosts that have disappeared.
2109:
2110: =item
2111:
2112: QUITs children for hosts that already exist (this just forces a status display
2113: and resets the connection retry count for that host.
2114:
2115: =item
2116:
2117: Starts new children for hosts that have been added to the hosts.tab file since
2118: the start of the master program and maintains them.
2119:
2120: =cut
2121:
2122: sub UpdateKids {
2123:
2124: Log("INFO", "Updating connections via SIGUSR2");
2125:
2126: # I'm not sure what I was thinking in the first implementation.
2127: # someone will have to work hard to convince me the effect is any
2128: # different than Restart, especially now that we don't start up
2129: # per host servers automatically, may as well just restart.
2130: # The down side is transactions that are in flight will get timed out
2131: # (lost unless they are critical).
2132:
2133: &KillThemAll();
2134: }
2135:
2136:
2137: =pod
2138:
2139: =head1 Restart
2140:
2141: Signal handler for HUP... all children are killed and
2142: we self restart. This is an el-cheapo way to re read
2143: the config file.
2144:
2145: =cut
2146:
2147: sub Restart {
2148: &KillThemAll; # First kill all the children.
2149: Log("CRITICAL", "Restarting");
2150: my $execdir = $perlvar{'lonDaemons'};
2151: unlink("$execdir/logs/lonc.pid");
2152: exec("$executable");
2153: }
2154:
2155: =pod
2156:
2157: =head1 KillThemAll
2158:
2159: Signal handler that kills all children by sending them a
2160: SIGHUP. Responds to sigint and sigterm.
2161:
2162: =cut
2163:
2164: sub KillThemAll {
2165: Debug(2, "Kill them all!!");
2166:
2167: #local($SIG{CHLD}) = 'IGNORE';
2168: # Our children >will< die.
2169: # but we need to catch their death and cleanup after them in case this is
2170: # a restart set of kills
2171: my @allpids = keys(%ChildPid);
2172: foreach my $pid (@allpids) {
2173: my $serving = $ChildPid{$pid};
2174: ShowStatus("Nicely Killing lonc for $serving pid = $pid");
2175: Log("CRITICAL", "Nicely Killing lonc for $serving pid = $pid");
2176: kill 'QUIT' => $pid;
2177: }
2178: ShowStatus("Finished killing child processes off.");
2179: }
2180:
2181:
2182: #
2183: # Kill all children via KILL. Just in case the
2184: # first shot didn't get them.
2185:
2186: sub really_kill_them_all_dammit
2187: {
2188: Debug(2, "Kill them all Dammit");
2189: local($SIG{CHLD} = 'IGNORE'); # In case some purist reenabled them.
2190: foreach my $pid (keys %ChildPid) {
2191: my $serving = $ChildPid{$pid};
2192: &ShowStatus("Nastily killing lonc for $serving pid = $pid");
2193: Log("CRITICAL", "Nastily killing lonc for $serving pid = $pid");
2194: kill 'KILL' => $pid;
2195: delete($ChildPid{$pid});
2196: my $execdir = $perlvar{'lonDaemons'};
2197: unlink("$execdir/logs/lonc.pid");
2198: }
2199: }
2200:
2201: =pod
2202:
2203: =head1 Terminate
2204:
2205: Terminate the system.
2206:
2207: =cut
2208:
2209: sub Terminate {
2210: &Log("CRITICAL", "Asked to kill children.. first be nice...");
2211: &KillThemAll;
2212: #
2213: # By now they really should all be dead.. but just in case
2214: # send them all SIGKILL's after a bit of waiting:
2215:
2216: sleep(4);
2217: &Log("CRITICAL", "Now kill children nasty");
2218: &really_kill_them_all_dammit;
2219: Log("CRITICAL","Master process exiting");
2220: exit 0;
2221:
2222: }
2223:
2224: sub my_hostname {
2225: use Sys::Hostname;
2226: my $name = &hostname();
2227: &Debug(9,"Name is $name");
2228: return $name;
2229: }
2230:
2231: =pod
2232:
2233: =head1 Theory
2234:
2235: The event class is used to build this as a single process with an
2236: event driven model. The following events are handled:
2237:
2238: =item UNIX Socket connection Received
2239:
2240: =item Request data arrives on UNIX data transfer socket.
2241:
2242: =item lond connection becomes writable.
2243:
2244: =item timer fires at 1 second intervals.
2245:
2246: All sockets are run in non-blocking mode. Timeouts managed by the timer
2247: handler prevents hung connections.
2248:
2249: Key data structures:
2250:
2251: =item RequestQueue
2252:
2253: A queue of requests received from UNIX sockets that are
2254: waiting for a chance to be forwarded on a lond connection socket.
2255:
2256: =item ActiveConnections
2257:
2258: A hash of lond connections that have transactions in process that are
2259: available to be timed out.
2260:
2261: =item ActiveTransactions
2262:
2263: A hash indexed by lond connections that contain the client reply
2264: socket for each connection that has an active transaction on it.
2265:
2266: =item IdleConnections
2267:
2268: A hash of lond connections that have no work to do. These connections
2269: can be closed if they are idle for a long enough time.
2270:
2271: =cut
2272:
2273: =pod
2274:
2275: =head1 Log messages
2276:
2277: The following is a list of log messages that can appear in the
2278: lonc.log file. Each log file has a severity and a message.
2279:
2280: =over 2
2281:
2282: =item Warning A socket timeout was detected
2283:
2284: If there are pending transactions in the socket's queue,
2285: they are failed (saved if critical). If the connection
2286: retry count gets exceeded by this, the
2287: remote host is marked as dead.
2288: Called when timeouts occured during the connection and
2289: connection dialog with a remote host.
2290:
2291: =item Critical Host makred DEAD <hostname>
2292:
2293: The numer of retry counts for contacting a host was
2294: exceeded. The host is marked dead an no
2295: further attempts will be made by that child.
2296:
2297: =item Info lonc pipe client hung up on us
2298:
2299: Write to the client pipe indicated no data transferred
2300: Socket to remote host is shut down. Reply to the client
2301: is discarded. Note: This is commented out in &ClientWriteable
2302:
2303: =item Success Reply from lond: <data>
2304:
2305: Can be enabled for debugging by setting LogTransactions to nonzero.
2306: Indicates a successful transaction with lond, <data> is the data received
2307: from the remote lond.
2308:
2309: =item Success A delayed transaction was completed
2310:
2311: A transaction that must be reliable was executed and completed
2312: as lonc restarted. This is followed by a mesage of the form
2313:
2314: S: client-name : request
2315:
2316: =item WARNING Failing transaction <cmd>:<subcmd>
2317:
2318: Transaction failed on a socket, but the failure retry count for the remote
2319: node has not yet been exhausted (the node is not yet marked dead).
2320: cmd is the command, subcmd is the subcommand. This results from a con_lost
2321: when communicating with lond.
2322:
2323: =item WARNING Shutting down a socket
2324:
2325: Called when a socket is being closed to lond. This is emitted both when
2326: idle pruning is being done and when the socket has been disconnected by the remote.
2327:
2328: =item WARNING Lond connection lost.
2329:
2330: Called when a read from lond's socket failed indicating lond has closed the
2331: connection or died. This should be followed by one or more
2332:
2333: "WARNING Failing transaction..." msgs for each in-flight or queued transaction.
2334:
2335: =item INFO Connected to lond version: <version>
2336:
2337: When connection negotiation is complete, the lond version is requested and logged here.
2338:
2339: =item SUCCESS Connection n to host now ready for action
2340:
2341: Emitted when connection has been completed with lond. n is then number of
2342: concurrent connections and host, the host to which the connection has just
2343: been established.
2344:
2345: =item WARNING Connection to host has been disconnected
2346:
2347: Write to a lond resulted in failure status. Connection to lond is dropped.
2348:
2349: =item SUCCESS Created connection n to host host
2350:
2351: Initial connection request to host..(before negotiation).
2352:
2353: =item CRITICAL Request Close Connection ... exiting
2354:
2355: Client has sent "close_connection_exit" The loncnew server is exiting.
2356:
2357: =item INFO Resetting Connection Retries
2358:
2359: Client has sent "reset_retries" The lond connection retries are reset to zero for the
2360: corresponding lond.
2361:
2362: =item SUCCESS Transaction <data>
2363:
2364: Only emitted if the global variable $LogTransactions was set to true.
2365: A client has requested a lond transaction <data> is the contents of the request.
2366:
2367: =item SUCCESS Toggled transaction logging <LogTransactions>
2368:
2369: The state of the $LogTransactions global has been toggled, and its current value
2370: (after being toggled) is displayed. When non zero additional logging of transactions
2371: is enabled for debugging purposes. Transaction logging is toggled on receipt of a USR2
2372: signal.
2373:
2374: =item CRITICAL Abnormal exit. Child <pid> for <host> died thorugh signal.
2375:
2376: QUIT signal received. lonc child process is exiting.
2377:
2378: =item SUCCESS New debugging level for <RemoteHost> now <DebugLevel>
2379:
2380: Debugging toggled for the host loncnew is talking with.
2381: Currently debugging is a level based scheme with higher number
2382: conveying more information. The daemon starts out at
2383: DebugLevel 0 and can toggle back and forth between that and
2384: DebugLevel 2 These are controlled by
2385: the global variables $DebugLevel and $NextDebugLevel
2386: The debug level can go up to 9.
2387: SIGINT toggles the debug level. The higher the debug level the
2388: more debugging information is spewed. See the Debug
2389: sub in loncnew.
2390:
2391: =item CRITICAL Forking server for host
2392:
2393: A child is being created to service requests for the specified host.
2394:
2395:
2396: =item WARNING Request for a second child on hostname
2397:
2398: Somehow loncnew was asked to start a second child on a host that already had a child
2399: servicing it. This request is not honored, but themessage is emitted. This could happen
2400: due to a race condition. When a client attempts to contact loncnew for a new host, a child
2401: is forked off to handle the requests for that server. The parent then backs off the Unix
2402: domain socket leaving it for the child to service all requests. If in the time between
2403: creating the child, and backing off, a new connection request comes in to the unix domain
2404: socket, this could trigger (unlikely but remotely possible),.
2405:
2406: =item CRITICAL ------ Starting Children ----
2407:
2408: This message should probably be changed to "Entering event loop" as the loncnew only starts
2409: children as needed. This message is emitted as new events are established and
2410: the event processing loop is entered.
2411:
2412: =item INFO Updating connections via SIGUSR2
2413:
2414: SIGUSR2 received. The original code would kill all clients, re-read the host file,
2415: then restart children for each host. Now that childrean aree started on demand, this
2416: just kills all child processes and lets requests start them as needed again.
2417:
2418:
2419: =item CRITICAL Restarting
2420:
2421: SigHUP received. all the children are killed and the script exec's itself to start again.
2422:
2423: =item CRITICAL Nicely killing lonc for host pid = <pid>
2424:
2425: Attempting to kill the child that is serving the specified host (pid given) cleanly via
2426: SIGQUIT The child should handle that, clean up nicely and exit.
2427:
2428: =item CRITICAL Nastily killing lonc for host pid = <pid>
2429:
2430: The child specified did not die when requested via SIGQUIT. Therefore it is killed
2431: via SIGKILL.
2432:
2433: =item CRITICAL Asked to kill children.. first be nice..
2434:
2435: In the parent's INT handler. INT kills the child processes. This inidicate loncnew
2436: is about to attempt to kill all known children via SIGQUIT. This message should be followed
2437: by one "Nicely killing" message for each extant child.
2438:
2439: =item CRITICAL Now kill children nasty
2440:
2441: In the parent's INT handler. remaining children are about to be killed via
2442: SIGKILL. Should be followed by a Nastily killing... for each lonc child that
2443: refused to die.
2444:
2445: =item CRITICAL Master process exiting
2446:
2447: In the parent's INT handler. just prior to the exit 0 call.
2448:
2449: =back
2450:
2451: =cut
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