File:
[LON-CAPA] /
loncom /
loncnew
Revision
1.109:
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Sun Jan 12 01:21:33 2020 UTC (4 years, 3 months ago) by
raeburn
Branches:
MAIN
CVS tags:
version_2_12_X,
HEAD
- Reverse change in rev. 1.102.
- the HostID of the peer is included in the string returned by:
$Transaction->getRequest().
- for a deferred transaction, the value of $Transaction->getClient() will
be undef.
1: #!/usr/bin/perl
2: # The LearningOnline Network with CAPA
3: # lonc maintains the connections to remote computers
4: #
5: # $Id: loncnew,v 1.109 2020/01/12 01:21:33 raeburn 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 over 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 %ChildKeyMode; # by pid -> keymode
78: my %listening_to; # Socket->host table for who the parent
79: # is listening to.
80: my %parent_dispatchers; # host-> listener watcher events.
81:
82: my %parent_handlers; # Parent signal handlers...
83:
84: my $MaxConnectionCount = 10; # Will get from config later.
85: my $ClientConnection = 0; # Uniquifier for client events.
86:
87: my $DebugLevel = 0;
88: my $NextDebugLevel= 2; # So Sigint can toggle this.
89: my $IdleTimeout= 5*60; # Seconds to wait prior to pruning connections.
90:
91: my $LogTransactions = 0; # When True, all transactions/replies get logged.
92: my $executable = $0; # Get the full path to me.
93:
94: #
95: # The variables below are only used by the child processes.
96: #
97: my $RemoteHost; # Hostname of host child is talking to.
98: my $RemoteHostId; # lonid of host child is talking to.
99: my $RemoteDefHostId; # default lonhostID of host child is talking to.
100: my $RemoteLoncapaRev; # LON-CAPA version of host child is talking to.
101: my @all_host_ids;
102: my $UnixSocketDir= $perlvar{'lonSockDir'};
103: my $IdleConnections = Stack->new(); # Set of idle connections
104: my %ActiveConnections; # Connections to the remote lond.
105: my %ActiveTransactions; # LondTransactions in flight.
106: my %ActiveClients; # Serial numbers of active clients by socket.
107: my $WorkQueue = Queue->new(); # Queue of pending transactions.
108: my $ConnectionCount = 0;
109: my $IdleSeconds = 0; # Number of seconds idle.
110: my $Status = ""; # Current status string.
111: my $RecentLogEntry = "";
112: my $ConnectionRetries=5; # Number of connection retries allowed.
113: my $ConnectionRetriesLeft=5; # Number of connection retries remaining.
114: my $LondVersion = "unknown"; # Version of lond we talk with.
115: my $KeyMode = ""; # e.g. ssl, local, insecure from last connect.
116: my $LondConnecting = 0; # True when a connection is being built.
117:
118:
119:
120: my $I_am_child = 0; # True if this is the child process.
121:
122: #
123: # The hash below gives the HTML format for log messages
124: # given a severity.
125: #
126: my %LogFormats;
127:
128: $LogFormats{"CRITICAL"} = "<font color='red'>CRITICAL: %s</font>";
129: $LogFormats{"SUCCESS"} = "<font color='green'>SUCCESS: %s</font>";
130: $LogFormats{"INFO"} = "<font color='yellow'>INFO: %s</font>";
131: $LogFormats{"WARNING"} = "<font color='blue'>WARNING: %s</font>";
132: $LogFormats{"DEFAULT"} = " %s ";
133:
134:
135: # UpdateStatus;
136: # Update the idle status display to show how many connections
137: # are left, retries and other stuff.
138: #
139: sub UpdateStatus {
140: if ($ConnectionRetriesLeft > 0) {
141: ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
142: ." Retries remaining: ".$ConnectionRetriesLeft
143: ." ($KeyMode)");
144: } else {
145: ShowStatus(GetServerHost()." >> DEAD <<");
146: }
147: }
148:
149:
150: =pod
151:
152: =head2 LogPerm
153:
154: Makes an entry into the permanent log file.
155:
156: =cut
157:
158: sub LogPerm {
159: my $message=shift;
160: my $execdir=$perlvar{'lonDaemons'};
161: my $now=time;
162: my $local=localtime($now);
163: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
164: chomp($message);
165: print $fh "$now:$message:$local\n";
166: }
167:
168: =pod
169:
170: =head2 Log
171:
172: Logs a message to the log file.
173: Parameters:
174:
175: =item severity
176:
177: One of CRITICAL, WARNING, INFO, SUCCESS used to select the
178: format string used to format the message. if the severity is
179: not a defined severity the Default format string is used.
180:
181: =item message
182:
183: The base message. In addtion to the format string, the message
184: will be appended to a string containing the name of our remote
185: host and the time will be formatted into the message.
186:
187: =cut
188:
189: sub Log {
190:
191: my ($severity, $message) = @_;
192:
193: if(!$LogFormats{$severity}) {
194: $severity = "DEFAULT";
195: }
196:
197: my $format = $LogFormats{$severity};
198:
199: # Put the window dressing in in front of the message format:
200:
201: my $now = time;
202: my $local = localtime($now);
203: my $finalformat = "$local ($$) [$RemoteHost] [$Status] ";
204: $finalformat = $finalformat.$format."\n";
205:
206: # open the file and put the result.
207:
208: my $execdir = $perlvar{'lonDaemons'};
209: my $fh = IO::File->new(">>$execdir/logs/lonc.log");
210: my $msg = sprintf($finalformat, $message);
211: $RecentLogEntry = $msg;
212: print $fh $msg;
213:
214:
215: }
216:
217:
218: =pod
219:
220: =head2 GetPeerName
221:
222: Returns the name of the host that a socket object is connected to.
223:
224: =cut
225:
226: sub GetPeername {
227:
228:
229: my ($connection, $AdrFamily) = @_;
230:
231: my $peer = $connection->peername();
232: my $peerport;
233: my $peerip;
234: if($AdrFamily == AF_INET) {
235: ($peerport, $peerip) = sockaddr_in($peer);
236: my $peername = gethostbyaddr($peerip, $AdrFamily);
237: return $peername;
238: } elsif ($AdrFamily == AF_UNIX) {
239: my $peerfile;
240: ($peerfile) = sockaddr_un($peer);
241: return $peerfile;
242: }
243: }
244: =pod
245:
246: =head2 Debug
247:
248: Invoked to issue a debug message.
249:
250: =cut
251:
252: sub Debug {
253:
254: my ($level, $message) = @_;
255:
256: if ($level <= $DebugLevel) {
257: Log("INFO", "-Debug- $message host = $RemoteHost");
258: }
259: }
260:
261: sub SocketDump {
262:
263: my ($level, $socket) = @_;
264:
265: if($level <= $DebugLevel) {
266: $socket->Dump(-1); # Ensure it will get dumped.
267: }
268: }
269:
270: =pod
271:
272: =head2 ShowStatus
273:
274: Place some text as our pid status.
275: and as what we return in a SIGUSR1
276:
277: =cut
278:
279: sub ShowStatus {
280: my $state = shift;
281: my $now = time;
282: my $local = localtime($now);
283: $Status = $local.": ".$state;
284: $0='lonc: '.$state.' '.$local;
285: }
286:
287: =pod
288:
289: =head2 SocketTimeout
290:
291: Called when an action on the socket times out. The socket is
292: destroyed and any active transaction is failed.
293:
294:
295: =cut
296:
297: sub SocketTimeout {
298: my $Socket = shift;
299: Log("WARNING", "A socket timeout was detected");
300: Debug(5, " SocketTimeout called: ");
301: $Socket->Dump(0);
302: if(exists($ActiveTransactions{$Socket})) {
303: FailTransaction($ActiveTransactions{$Socket});
304: }
305: KillSocket($Socket); # A transaction timeout also counts as
306: # a connection failure:
307: $ConnectionRetriesLeft--;
308: if($ConnectionRetriesLeft <= 0) {
309: Log("CRITICAL", "Host marked DEAD: ".GetServerHost());
310: $LondConnecting = 0;
311: }
312:
313: }
314:
315: #
316: # This function should be called by the child in all cases where it must
317: # exit. The child process must create a lock file for the AF_UNIX socket
318: # in order to prevent connection requests from lonnet in the time between
319: # process exit and the parent picking up the listen again.
320: #
321: # Parameters:
322: # exit_code - Exit status value, however see the next parameter.
323: # message - If this optional parameter is supplied, the exit
324: # is via a die with this message.
325: #
326: sub child_exit {
327: my ($exit_code, $message) = @_;
328:
329: # Regardless of how we exit, we may need to do the lock thing:
330:
331: #
332: # Create a lock file since there will be a time window
333: # between our exit and the parent's picking up the listen
334: # during which no listens will be done on the
335: # lonnet client socket.
336: #
337: my $lock_file = &GetLoncSocketPath().".lock";
338: open(LOCK,">$lock_file");
339: print LOCK "Contents not important";
340: close(LOCK);
341: unlink(&GetLoncSocketPath());
342:
343: if ($message) {
344: die($message);
345: } else {
346: exit($exit_code);
347: }
348: }
349: #----------------------------- Timer management ------------------------
350:
351: =pod
352:
353: =head2 Tick
354:
355: Invoked each timer tick.
356:
357: =cut
358:
359:
360: sub Tick {
361: my ($Event) = @_;
362: my $clock_watcher = $Event->w;
363:
364: my $client;
365: UpdateStatus();
366:
367: # Is it time to prune connection count:
368:
369:
370: if($IdleConnections->Count() &&
371: ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
372: $IdleSeconds++;
373: if($IdleSeconds > $IdleTimeout) { # Prune a connection...
374: my $Socket = $IdleConnections->pop();
375: KillSocket($Socket);
376: $IdleSeconds = 0; # Otherwise all connections get trimmed to fast.
377: UpdateStatus();
378: if(($ConnectionCount == 0)) {
379: &child_exit(0);
380:
381: }
382: }
383: } else {
384: $IdleSeconds = 0; # Reset idle count if not idle.
385: }
386: #
387: # For each inflight transaction, tick down its timeout counter.
388: #
389:
390: foreach my $item (keys %ActiveConnections) {
391: my $State = $ActiveConnections{$item}->data->GetState();
392: if ($State ne 'Idle') {
393: Debug(5,"Ticking Socket $State $item");
394: $ActiveConnections{$item}->data->Tick();
395: }
396: }
397: # Do we have work in the queue, but no connections to service them?
398: # If so, try to make some new connections to get things going again.
399: #
400: # Note this code is dead now...
401: #
402: my $Requests = $WorkQueue->Count();
403: if (($ConnectionCount == 0) && ($Requests > 0) && (!$LondConnecting)) {
404: if ($ConnectionRetriesLeft > 0) {
405: Debug(5,"Work but no connections, Make a new one");
406: my $success;
407: $success = &MakeLondConnection;
408: if($success == 0) { # All connections failed:
409: Debug(5,"Work in queue failed to make any connectiouns\n");
410: EmptyQueue(); # Fail pending transactions with con_lost.
411: CloseAllLondConnections(); # Should all be closed but....
412: }
413: } else {
414: $LondConnecting = 0;
415: ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
416: Debug(5,"Work in queue, but gave up on connections..flushing\n");
417: EmptyQueue(); # Connections can't be established.
418: CloseAllLondConnections(); # Should all already be closed but...
419: }
420:
421: }
422: if ($ConnectionCount == 0) {
423: $KeyMode = "";
424: $clock_watcher->cancel();
425: }
426: &UpdateStatus();
427: }
428:
429: =pod
430:
431: =head2 SetupTimer
432:
433: Sets up a 1 per sec recurring timer event. The event handler is used to:
434:
435: =item
436:
437: Trigger timeouts on communications along active sockets.
438:
439: =item
440:
441: Trigger disconnections of idle sockets.
442:
443: =cut
444:
445: sub SetupTimer {
446: Debug(6, "SetupTimer");
447: Event->timer(interval => 1, cb => \&Tick,
448: hard => 1);
449: }
450:
451: =pod
452:
453: =head2 ServerToIdle
454:
455: This function is called when a connection to the server is
456: ready for more work.
457:
458: If there is work in the Work queue the top element is dequeued
459: and the connection will start to work on it. If the work queue is
460: empty, the connection is pushed on the idle connection stack where
461: it will either get another work unit, or alternatively, if it sits there
462: long enough, it will be shut down and released.
463:
464: =cut
465:
466: sub ServerToIdle {
467: my $Socket = shift; # Get the socket.
468: $KeyMode = $Socket->{AuthenticationMode};
469: delete($ActiveTransactions{$Socket}); # Server has no transaction
470:
471: &Debug(5, "Server to idle");
472:
473: # If there's work to do, start the transaction:
474:
475: my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
476: if ($reqdata ne undef) {
477: Debug(5, "Queue gave request data: ".$reqdata->getRequest());
478: &StartRequest($Socket, $reqdata);
479:
480: } else {
481:
482: # There's no work waiting, so push the server to idle list.
483: &Debug(5, "No new work requests, server connection going idle");
484: $IdleConnections->push($Socket);
485: }
486: }
487:
488: =pod
489:
490: =head2 ClientWritable
491:
492: Event callback for when a client socket is writable.
493:
494: This callback is established when a transaction response is
495: available from lond. The response is forwarded to the unix socket
496: as it becomes writable in this sub.
497:
498: Parameters:
499:
500: =item Event
501:
502: The event that has been triggered. Event->w->data is
503: the data and Event->w->fd is the socket to write.
504:
505: =cut
506:
507: sub ClientWritable {
508: my $Event = shift;
509: my $Watcher = $Event->w;
510: if (!defined($Watcher)) {
511: &child_exit(-1,'No watcher for event in ClientWritable');
512: }
513: my $Data = $Watcher->data;
514: my $Socket = $Watcher->fd;
515:
516: # Try to send the data:
517:
518: &Debug(6, "ClientWritable writing".$Data);
519: &Debug(9, "Socket is: ".$Socket);
520:
521: if($Socket->connected) {
522: my $result = $Socket->send($Data, 0);
523:
524: # $result undefined: the write failed.
525: # otherwise $result is the number of bytes written.
526: # Remove that preceding string from the data.
527: # If the resulting data is empty, destroy the watcher
528: # and set up a read event handler to accept the next
529: # request.
530:
531: &Debug(9,"Send result is ".$result." Defined: ".defined($result));
532: if($result ne undef) {
533: &Debug(9, "send result was defined");
534: if($result == length($Data)) { # Entire string sent.
535: &Debug(9, "ClientWritable data all written");
536: $Watcher->cancel();
537: #
538: # Set up to read next request from socket:
539:
540: my $descr = sprintf("Connection to lonc client %d",
541: $ActiveClients{$Socket});
542: Event->io(cb => \&ClientRequest,
543: poll => 'r',
544: desc => $descr,
545: data => "",
546: fd => $Socket);
547:
548: } else { # Partial string sent.
549: $Watcher->data(substr($Data, $result));
550: if($result == 0) { # client hung up on us!!
551: # Log("INFO", "lonc pipe client hung up on us!");
552: $Watcher->cancel;
553: $Socket->shutdown(2);
554: $Socket->close();
555: }
556: }
557:
558: } else { # Error of some sort...
559:
560: # Some errnos are possible:
561: my $errno = $!;
562: if($errno == POSIX::EWOULDBLOCK ||
563: $errno == POSIX::EAGAIN ||
564: $errno == POSIX::EINTR) {
565: # No action taken...the socket will be writable firing the event again
566: # which will result in a retry of the write.
567: } else { # Unanticipated errno.
568: &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
569: $Watcher->cancel; # Stop the watcher.
570: $Socket->shutdown(2); # Kill connection
571: $Socket->close(); # Close the socket.
572: }
573:
574: }
575: } else {
576: $Watcher->cancel(); # A delayed request...just cancel.
577: return;
578: }
579: }
580:
581: =pod
582:
583: =head2 CompleteTransaction
584:
585: Called when the reply data has been received for a lond
586: transaction. The reply data must now be sent to the
587: ultimate client on the other end of the Unix socket. This is
588: done by setting up a writable event for the socket with the
589: data the reply data.
590:
591: Parameters:
592:
593: =item Socket
594:
595: Socket on which the lond transaction occurred. This is a
596: LondConnection. The data received are in the TransactionReply member.
597:
598: =item Transaction
599:
600: The transaction that is being completed.
601:
602: =cut
603:
604: sub CompleteTransaction {
605: &Debug(5,"Complete transaction");
606:
607: my ($Socket, $Transaction) = @_;
608:
609: if (!$Transaction->isDeferred()) { # Normal transaction
610: my $data = $Socket->GetReply(); # Data to send.
611: if($LogTransactions) {
612: Log("SUCCESS", "Reply from lond: '$data'");
613: }
614: StartClientReply($Transaction, $data);
615: } else { # Delete deferred transaction file.
616: Log("SUCCESS", "A delayed transaction was completed");
617: LogPerm("S:".$Transaction->getClient().":".$Transaction->getRequest());
618: unlink($Transaction->getFile());
619: }
620: }
621:
622: =pod
623:
624: =head1 StartClientReply
625:
626: Initiates a reply to a client where the reply data is a parameter.
627:
628: =head2 parameters:
629:
630: =item Transaction
631:
632: The transaction for which we are responding to the client.
633:
634: =item data
635:
636: The data to send to apache client.
637:
638: =cut
639:
640: sub StartClientReply {
641:
642: my ($Transaction, $data) = @_;
643:
644: my $Client = $Transaction->getClient();
645:
646: &Debug(8," Reply was: ".$data);
647: my $Serial = $ActiveClients{$Client};
648: my $desc = sprintf("Connection to lonc client %d",
649: $Serial);
650: Event->io(fd => $Client,
651: poll => "w",
652: desc => $desc,
653: cb => \&ClientWritable,
654: data => $data);
655: }
656:
657: =pod
658:
659: =head2 FailTransaction
660:
661: Finishes a transaction with failure because the associated lond socket
662: disconnected. There are two possibilities:
663: - The transaction is deferred: in which case we just quietly
664: delete the transaction since there is no client connection.
665: - The transaction is 'live' in which case we initiate the sending
666: of "con_lost" to the client.
667:
668: Deleting the transaction means killing it from the %ActiveTransactions hash.
669:
670: Parameters:
671:
672: =item client
673:
674: The LondTransaction we are failing.
675:
676: =cut
677:
678: sub FailTransaction {
679: my $transaction = shift;
680:
681: # If the socket is dead, that's already logged.
682:
683: if ($ConnectionRetriesLeft > 0) {
684: Log("WARNING", "Failing transaction "
685: .$transaction->getLoggableRequest());
686: }
687: Debug(1, "Failing transaction: ".$transaction->getLoggableRequest());
688: if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
689: my $client = $transaction->getClient();
690: Debug(1," Replying con_lost to ".$transaction->getRequest());
691: StartClientReply($transaction, "con_lost\n");
692: }
693:
694: }
695:
696: =pod
697:
698: =head1 EmptyQueue
699:
700: Fails all items in the work queue with con_lost.
701: Note that each item in the work queue is a transaction.
702:
703: =cut
704:
705: sub EmptyQueue {
706: $ConnectionRetriesLeft--; # Counts as connection failure too.
707: while($WorkQueue->Count()) {
708: my $request = $WorkQueue->dequeue(); # This is a transaction
709: FailTransaction($request);
710: }
711: }
712:
713: =pod
714:
715: =head2 CloseAllLondConnections
716:
717: Close all connections open on lond prior to exit e.g.
718:
719: =cut
720:
721: sub CloseAllLondConnections {
722: foreach my $Socket (keys %ActiveConnections) {
723: if(exists($ActiveTransactions{$Socket})) {
724: FailTransaction($ActiveTransactions{$Socket});
725: }
726: KillSocket($Socket);
727: }
728: }
729:
730: =pod
731:
732: =head2 KillSocket
733:
734: Destroys a socket. This function can be called either when a socket
735: has died of 'natural' causes or because a socket needs to be pruned due to
736: idleness. If the socket has died naturally, if there are no longer any
737: live connections a new connection is created (in case there are transactions
738: in the queue). If the socket has been pruned, it is never re-created.
739:
740: Parameters:
741:
742: =item Socket
743:
744: The socket to kill off.
745:
746: =item restart
747:
748: non-zero if we are allowed to create a new connection.
749:
750: =cut
751:
752: sub KillSocket {
753: my $Socket = shift;
754: my $restart = shift;
755:
756: Log("WARNING", "Shutting down a socket");
757: $Socket->Shutdown();
758:
759: # If the socket came from the active connection set,
760: # delete its transaction... note that FailTransaction should
761: # already have been called!!!
762: # otherwise it came from the idle set.
763: #
764:
765: if(exists($ActiveTransactions{$Socket})) {
766: delete ($ActiveTransactions{$Socket});
767: }
768: if(exists($ActiveConnections{$Socket})) {
769: $ActiveConnections{$Socket}->cancel;
770: delete($ActiveConnections{$Socket});
771: # Decrement ConnectionCount unless we will immediately
772: # re-connect (i.e., $restart is true), because this was
773: # a connection where the SSL channel for exchange of the
774: # shared key failed, and we may use an insecure channel.
775: unless ($restart) {
776: $ConnectionCount--;
777: }
778: if ($ConnectionCount < 0) { $ConnectionCount = 0; }
779: }
780: # If the connection count has gone to zero and there is work in the
781: # work queue, the work all gets failed with con_lost.
782: #
783:
784: if($ConnectionCount == 0) {
785: $LondConnecting = 0; # No connections so also not connecting.
786: EmptyQueue();
787: CloseAllLondConnections(); # Should all already be closed but...
788: &clear_childpid($$);
789: }
790: UpdateStatus();
791: }
792:
793: =pod
794:
795: =head2 LondReadable
796:
797: This function is called whenever a lond connection
798: is readable. The action is state dependent:
799:
800: =head3 State=Initialized
801:
802: We are waiting for the challenge, this is a no-op until the
803: state changes.
804:
805: =head3 State=Challenged
806:
807: The challenge has arrived we need to transition to Writable.
808: The connection must echo the challenge back.
809:
810: =head3 State=ChallengeReplied
811:
812: The challenge has been replied to. Then we are receiving the
813: 'ok' from the partner.
814:
815: =head3 State=ReadingVersionString
816:
817: We have requested the lond version and are reading the
818: version back. Upon completion, we'll store the version away
819: for future use(?).
820:
821: =head3 State=HostSet
822:
823: We have selected the domain name of our peer (multhomed hosts)
824: and are getting the reply (presumably ok) back.
825:
826: =head3 State=RequestingKey
827:
828: The ok has been received and we need to send the request for
829: an encryption key. Transition to writable for that.
830:
831: =head3 State=ReceivingKey
832:
833: The the key has been requested, now we are reading the new key.
834:
835: =head3 State=Idle
836:
837: The encryption key has been negotiated or we have finished
838: reading data from the a transaction. If the callback data have
839: a client as well as the socket information, then we are
840: doing a transaction and the data received are relayed to the client
841: before the socket is put on the idle list.
842:
843: =head3 State=SendingRequest
844:
845: I do not think this state can be received here, but if it is,
846: the appropriate thing to do is to transition to writable, and send
847: the request.
848:
849: =head3 State=ReceivingReply
850:
851: We finished sending the request to the server and now transition
852: to readable to receive the reply.
853:
854: The parameter to this function are:
855:
856: The event. Implicit in this is the watcher and its data. The data
857: contain at least the lond connection object and, if a
858: transaction is in progress, the socket attached to the local client.
859:
860: =cut
861:
862: sub LondReadable {
863:
864: my $Event = shift;
865: my $Watcher = $Event->w;
866: my $Socket = $Watcher->data;
867: my $client = undef;
868:
869: &Debug(6,"LondReadable called state = ".$Socket->GetState());
870:
871:
872: my $State = $Socket->GetState(); # All action depends on the state.
873:
874: SocketDump(6, $Socket);
875: my $status = $Socket->Readable();
876:
877: &Debug(2, "Socket->Readable returned: $status");
878:
879: if($status != 0) {
880: # bad return from socket read. Currently this means that
881: # The socket has become disconnected. We fail the transaction.
882:
883: Log("WARNING",
884: "Lond connection lost.");
885: my $state_on_exit = $Socket->GetState();
886: if(exists($ActiveTransactions{$Socket})) {
887: FailTransaction($ActiveTransactions{$Socket});
888: } else {
889: # Socket is connecting and failed... need to mark
890: # no longer connecting.
891: $LondConnecting = 0;
892: }
893: $Watcher->cancel();
894: if ($state_on_exit eq 'ReInitNoSSL') {
895: # SSL certificate verification failed, and insecure connection
896: # allowed. Send restart arg to KillSocket(), so EmptyQueue()
897: # is not called, as we still hope to process queued request.
898:
899: KillSocket($Socket,1);
900:
901: # Re-initiate creation of Lond Connection for use with queued
902: # request.
903:
904: ShowStatus("Connected to ".$RemoteHost);
905: Log("WARNING","No SSL channel (verification failed), will try with insecure channel");
906: &MakeLondConnection(1);
907:
908: } else {
909: KillSocket($Socket);
910: $ConnectionRetriesLeft--; # Counts as connection failure
911: }
912: return;
913: }
914: SocketDump(6,$Socket);
915:
916: $State = $Socket->GetState(); # Update in case of transition.
917: &Debug(6, "After read, state is ".$State);
918:
919: if($State eq "Initialized") {
920:
921:
922: } elsif ($State eq "ReInitNoSSL") {
923:
924: } elsif ($State eq "ChallengeReceived") {
925: # The challenge must be echoed back; The state machine
926: # in the connection takes care of setting that up. Just
927: # need to transition to writable:
928:
929: $Watcher->cb(\&LondWritable);
930: $Watcher->poll("w");
931:
932: } elsif ($State eq "ChallengeReplied") {
933:
934: } elsif ($State eq "RequestingVersion") {
935: # Need to ask for the version... that is writiability:
936:
937: $Watcher->cb(\&LondWritable);
938: $Watcher->poll("w");
939:
940: } elsif ($State eq "ReadingVersionString") {
941: # Read the rest of the version string...
942: } elsif ($State eq "SetHost") {
943: # Need to request the actual domain get set...
944:
945: $Watcher->cb(\&LondWritable);
946: $Watcher->poll("w");
947: } elsif ($State eq "HostSet") {
948: # Reading the 'ok' from the peer.
949:
950: } elsif ($State eq "RequestingKey") {
951: # The ok was received. Now we need to request the key
952: # That requires us to be writable:
953:
954: $Watcher->cb(\&LondWritable);
955: $Watcher->poll("w");
956:
957: } elsif ($State eq "ReceivingKey") {
958:
959: } elsif ($State eq "Idle") {
960:
961: if ($ConnectionCount == 1) {
962: # Write child Pid file to keep track of ssl and insecure
963: # connections
964:
965: &record_childpid($Socket);
966: }
967:
968: # This is as good a spot as any to get the peer version
969: # string:
970:
971: if($LondVersion eq "unknown") {
972: $LondVersion = $Socket->PeerVersion();
973: Log("INFO", "Connected to lond version: $LondVersion");
974: }
975: # If necessary, complete a transaction and then go into the
976: # idle queue.
977: # Note that a trasition to idle indicates a live lond
978: # on the other end so reset the connection retries.
979: #
980: $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
981: $Watcher->cancel();
982: if(exists($ActiveTransactions{$Socket})) {
983: Debug(5,"Completing transaction!!");
984: CompleteTransaction($Socket,
985: $ActiveTransactions{$Socket});
986: } else {
987: my $count = $Socket->GetClientData();
988: Log("SUCCESS", "Connection ".$count." to "
989: .$RemoteHost." now ready for action");
990: }
991: ServerToIdle($Socket); # Next work unit or idle.
992:
993: #
994: $LondConnecting = 0; # Best spot I can think of for this.
995: #
996:
997: } elsif ($State eq "SendingRequest") {
998: # We need to be writable for this and probably don't belong
999: # here inthe first place.
1000:
1001: Debug(6, "SendingRequest state encountered in readable");
1002: $Watcher->poll("w");
1003: $Watcher->cb(\&LondWritable);
1004:
1005: } elsif ($State eq "ReceivingReply") {
1006:
1007:
1008: } else {
1009: # Invalid state.
1010: Debug(4, "Invalid state in LondReadable");
1011: }
1012: }
1013:
1014: =pod
1015:
1016: =head2 LondWritable
1017:
1018: This function is called whenever a lond connection
1019: becomes writable while there is a writeable monitoring
1020: event. The action taken is very state dependent:
1021:
1022: =head3 State = Connected
1023:
1024: The connection is in the process of sending the 'init' hailing to the
1025: lond on the remote end. The Writable member of the connection object
1026: is called. On error, call ConnectionError to destroy the connection
1027: and remove it from the ActiveConnections hash.
1028:
1029: =head3 Initialized
1030:
1031: 'init' has been sent, writability monitoring is removed and
1032: readability monitoring is started with LondReadable as the callback.
1033:
1034: =head3 ChallengeReceived
1035:
1036: The connection has received the who are you challenge from the remote
1037: system, and is in the process of sending the challenge
1038: response. Writable is called.
1039:
1040: =head3 ChallengeReplied
1041:
1042: The connection has replied to the initial challenge The we switch to
1043: monitoring readability looking for the server to reply with 'ok'.
1044:
1045: =head3 RequestingKey
1046:
1047: The connection is in the process of requesting its encryption key.
1048: Writable is called.
1049:
1050: =head3 ReceivingKey
1051:
1052: The connection has sent the request for a key. Switch to readability
1053: monitoring to accept the key
1054:
1055: =head3 SendingRequest
1056:
1057: The connection is in the process of sending a request to the server.
1058: This request is part of a client transaction. All the states until
1059: now represent the client setup protocol. Writable is called.
1060:
1061: =head3 ReceivingReply
1062:
1063: The connection has sent a request. Now it must receive a reply.
1064: Readability monitoring is requested.
1065:
1066: This function is an event handler and therefore receives as
1067: a parameter the event that has fired. The data for the watcher
1068: of this event is a reference to a list of one or two elements,
1069: depending on state. The first (and possibly only) element is the
1070: socket. The second (present only if a request is in progress)
1071: is the socket on which to return a reply to the caller.
1072:
1073: =cut
1074:
1075: sub LondWritable {
1076: my $Event = shift;
1077: my $Watcher = $Event->w;
1078: my $Socket = $Watcher->data;
1079: my $State = $Socket->GetState();
1080:
1081: Debug(6,"LondWritable State = ".$State."\n");
1082:
1083:
1084: # Figure out what to do depending on the state of the socket:
1085:
1086:
1087:
1088:
1089: SocketDump(6,$Socket);
1090:
1091: # If the socket is writable, we must always write.
1092: # Only by writing will we undergo state transitions.
1093: # Old logic wrote in state specific code below, however
1094: # That forces us at least through another invocation of
1095: # this function after writability is possible again.
1096: # This logic also factors out common code for handling
1097: # write failures... in all cases, write failures
1098: # Kill the socket.
1099: # This logic makes the branches of the >big< if below
1100: # so that the writing states are actually NO-OPs.
1101:
1102: if ($Socket->Writable() != 0) {
1103: # The write resulted in an error.
1104: # We'll treat this as if the socket got disconnected:
1105: Log("WARNING", "Connection to ".$RemoteHost.
1106: " has been disconnected");
1107: if(exists($ActiveTransactions{$Socket})) {
1108: FailTransaction($ActiveTransactions{$Socket});
1109: } else {
1110: # In the process of conneting, so need to turn that off.
1111:
1112: $LondConnecting = 0;
1113: }
1114: $Watcher->cancel();
1115: KillSocket($Socket);
1116: return;
1117: }
1118:
1119:
1120:
1121: if ($State eq "Connected") {
1122:
1123: # "init" is being sent...
1124:
1125: } elsif ($State eq "Initialized") {
1126:
1127: # Now that init was sent, we switch
1128: # to watching for readability:
1129:
1130: $Watcher->cb(\&LondReadable);
1131: $Watcher->poll("r");
1132:
1133: } elsif ($State eq "ReInitNoSSL") {
1134:
1135: } elsif ($State eq "ChallengeReceived") {
1136: # We received the challenge, now we
1137: # are echoing it back. This is a no-op,
1138: # we're waiting for the state to change
1139:
1140: } elsif ($State eq "ChallengeReplied") {
1141: # The echo was sent back, so we switch
1142: # to watching readability.
1143:
1144: $Watcher->cb(\&LondReadable);
1145: $Watcher->poll("r");
1146: } elsif ($State eq "RequestingVersion") {
1147: # Sending the peer a version request...
1148:
1149: } elsif ($State eq "ReadingVersionString") {
1150: # Transition to read since we have sent the
1151: # version command and now just need to read the
1152: # version string from the peer:
1153:
1154: $Watcher->cb(\&LondReadable);
1155: $Watcher->poll("r");
1156:
1157: } elsif ($State eq "SetHost") {
1158: # Setting the remote domain...
1159:
1160: } elsif ($State eq "HostSet") {
1161: # Back to readable to get the ok.
1162:
1163: $Watcher->cb(\&LondReadable);
1164: $Watcher->poll("r");
1165:
1166:
1167: } elsif ($State eq "RequestingKey") {
1168: # At this time we're requesting the key.
1169: # again, this is essentially a no-op.
1170:
1171: } elsif ($State eq "ReceivingKey") {
1172: # Now we need to wait for the key
1173: # to come back from the peer:
1174:
1175: $Watcher->cb(\&LondReadable);
1176: $Watcher->poll("r");
1177:
1178: } elsif ($State eq "SendingRequest") {
1179:
1180: # At this time we are sending a request to the
1181: # peer... write the next chunk:
1182:
1183:
1184: } elsif ($State eq "ReceivingReply") {
1185: # The send has completed. Wait for the
1186: # data to come in for a reply.
1187: Debug(8,"Writable sent request/receiving reply");
1188: $Watcher->cb(\&LondReadable);
1189: $Watcher->poll("r");
1190:
1191: } else {
1192: # Control only passes here on an error:
1193: # the socket state does not match any
1194: # of the known states... so an error
1195: # must be logged.
1196:
1197: &Debug(4, "Invalid socket state ".$State."\n");
1198: }
1199:
1200: }
1201:
1202: =pod
1203:
1204: =cut
1205:
1206:
1207: sub QueueDelayed {
1208: Debug(3,"QueueDelayed called");
1209:
1210: my $path = "$perlvar{'lonSockDir'}/delayed";
1211:
1212: Debug(4, "Delayed path: ".$path);
1213: opendir(DIRHANDLE, $path);
1214:
1215: my $host_id_re = '(?:'.join('|',map {quotemeta($_)} (@all_host_ids)).')';
1216: my @alldelayed = grep(/\.$host_id_re$/, readdir(DIRHANDLE));
1217: closedir(DIRHANDLE);
1218: foreach my $dfname (sort(@alldelayed)) {
1219: my $reqfile = "$path/$dfname";
1220: my ($host_id) = ($dfname =~ /\.([^.]*)$/);
1221: Debug(4, "queueing ".$reqfile." for $host_id");
1222: my $Handle = IO::File->new($reqfile);
1223: my $cmd = <$Handle>;
1224: chomp $cmd; # There may or may not be a newline...
1225: $cmd = $cmd."\n"; # now for sure there's exactly one newline.
1226: my $Transaction = LondTransaction->new("sethost:$host_id:$cmd");
1227: $Transaction->SetDeferred($reqfile);
1228: QueueTransaction($Transaction);
1229: }
1230:
1231: }
1232:
1233: =pod
1234:
1235: =head2 MakeLondConnection
1236:
1237: Create a new lond connection object, and start it towards its initial
1238: idleness. Once idle, it becomes eligible to receive transactions
1239: from the work queue. If the work queue is not empty when the
1240: connection is completed and becomes idle, it will dequeue an entry and
1241: start off on it.
1242:
1243: =cut
1244:
1245: sub MakeLondConnection {
1246: my ($restart) = @_;
1247: Debug(4,"MakeLondConnection to ".GetServerHost()." on port "
1248: .GetServerPort());
1249:
1250: my $Connection = LondConnection->new(&GetServerHost(),
1251: &GetServerPort(),
1252: &GetHostId(),
1253: &GetDefHostId(),
1254: &GetLoncapaRev());
1255:
1256: if($Connection eq undef) {
1257: Log("CRITICAL","Failed to make a connection with lond.");
1258: $ConnectionRetriesLeft--;
1259: return 0; # Failure.
1260: } else {
1261: $LondConnecting = 1; # Connection in progress.
1262: # The connection needs to have writability
1263: # monitored in order to send the init sequence
1264: # that starts the whole authentication/key
1265: # exchange underway.
1266: #
1267: my $Socket = $Connection->GetSocket();
1268: if($Socket eq undef) {
1269: &child_exit(-1, "did not get a socket from the connection");
1270: } else {
1271: &Debug(9,"MakeLondConnection got socket: ".$Socket);
1272: }
1273:
1274: $Connection->SetTimeoutCallback(\&SocketTimeout);
1275:
1276: my $event = Event->io(fd => $Socket,
1277: poll => 'w',
1278: cb => \&LondWritable,
1279: data => $Connection,
1280: desc => 'Connection to lond server');
1281: $ActiveConnections{$Connection} = $event;
1282: if ($ConnectionCount == 0) {
1283: &SetupTimer; # Need to handle timeouts with connections...
1284: }
1285: unless ($restart) {
1286: $ConnectionCount++;
1287: }
1288: $Connection->SetClientData($ConnectionCount);
1289: Debug(4, "Connection count = ".$ConnectionCount);
1290: if($ConnectionCount == 1) { # First Connection:
1291: QueueDelayed;
1292: }
1293: Log("SUCCESS", "Created connection ".$ConnectionCount
1294: ." to host ".GetServerHost());
1295: return 1; # Return success.
1296: }
1297:
1298: }
1299:
1300: =pod
1301:
1302: =head2 StartRequest
1303:
1304: Starts a lond request going on a specified lond connection.
1305: parameters are:
1306:
1307: =item $Lond
1308:
1309: Connection to the lond that will send the transaction and receive the
1310: reply.
1311:
1312: =item $Client
1313:
1314: Connection to the client that is making this request. We got the
1315: request from this socket, and when the request has been relayed to
1316: lond and we get a reply back from lond it will get sent to this
1317: socket.
1318:
1319: =item $Request
1320:
1321: The text of the request to send.
1322:
1323: =cut
1324:
1325: sub StartRequest {
1326:
1327: my ($Lond, $Request) = @_;
1328:
1329: Debug(6, "StartRequest: ".$Request->getRequest());
1330:
1331: my $Socket = $Lond->GetSocket();
1332:
1333: $Request->Activate($Lond);
1334: $ActiveTransactions{$Lond} = $Request;
1335:
1336: $Lond->InitiateTransaction($Request->getRequest());
1337: my $event = Event->io(fd => $Socket,
1338: poll => "w",
1339: cb => \&LondWritable,
1340: data => $Lond,
1341: desc => "lond transaction connection");
1342: $ActiveConnections{$Lond} = $event;
1343: Debug(8," Start Request made watcher data with ".$event->data."\n");
1344: }
1345:
1346: =pod
1347:
1348: =head2 QueueTransaction
1349:
1350: If there is an idle lond connection, it is put to work doing this
1351: transaction. Otherwise, the transaction is placed in the work queue.
1352: If placed in the work queue and the maximum number of connections has
1353: not yet been created, a new connection will be started. Our goal is
1354: to eventually have a sufficient number of connections that the work
1355: queue will typically be empty. parameters are:
1356:
1357: =item Socket
1358:
1359: open on the lonc client.
1360:
1361: =item Request
1362:
1363: data to send to the lond.
1364:
1365: =cut
1366:
1367: sub QueueTransaction {
1368:
1369: my $requestData = shift; # This is a LondTransaction.
1370: my $cmd = $requestData->getRequest();
1371:
1372: Debug(6,"QueueTransaction: ".$cmd);
1373:
1374: my $LondSocket = $IdleConnections->pop();
1375: if(!defined $LondSocket) { # Need to queue request.
1376: Debug(5,"Must queue...");
1377: $WorkQueue->enqueue($requestData);
1378: Debug(5, "Queue Transaction startnew $ConnectionCount $LondConnecting");
1379: if(($ConnectionCount < $MaxConnectionCount) && (! $LondConnecting)) {
1380:
1381: if($ConnectionRetriesLeft > 0) {
1382: Debug(5,"Starting additional lond connection");
1383: if(&MakeLondConnection() == 0) {
1384: EmptyQueue(); # Fail transactions, can't make connection.
1385: CloseAllLondConnections; # Should all be closed but...
1386: }
1387: } else {
1388: ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
1389: $LondConnecting = 0;
1390: EmptyQueue(); # It's worse than that ... he's dead Jim.
1391: CloseAllLondConnections; # Should all be closed but..
1392: }
1393: }
1394: } else { # Can start the request:
1395: Debug(8,"Can start...");
1396: StartRequest($LondSocket, $requestData);
1397: }
1398: }
1399:
1400: #-------------------------- Lonc UNIX socket handling -------------------
1401: =pod
1402:
1403: =head2 ClientRequest
1404:
1405: Callback that is called when data can be read from the UNIX domain
1406: socket connecting us with an apache server process.
1407:
1408: =cut
1409:
1410: sub ClientRequest {
1411: Debug(6, "ClientRequest");
1412: my $event = shift;
1413: my $watcher = $event->w;
1414: my $socket = $watcher->fd;
1415: my $data = $watcher->data;
1416: my $thisread;
1417:
1418: Debug(9, " Watcher named: ".$watcher->desc);
1419:
1420: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1421: Debug(8, "rcv: data length = ".length($thisread)
1422: ." read =".$thisread);
1423: unless (defined $rv && length($thisread)) {
1424: # Likely eof on socket.
1425: Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
1426: close($socket);
1427: $watcher->cancel();
1428: delete($ActiveClients{$socket});
1429: return;
1430: }
1431: Debug(8,"Data: ".$data." this read: ".$thisread);
1432: $data = $data.$thisread; # Append new data.
1433: $watcher->data($data);
1434: if($data =~ /\n$/) { # Request entirely read.
1435: if ($data eq "close_connection_exit\n") {
1436: Log("CRITICAL",
1437: "Request Close Connection ... exiting");
1438: CloseAllLondConnections();
1439: exit;
1440: } elsif ($data eq "reset_retries\n") {
1441: Log("INFO", "Resetting Connection Retries.");
1442: $ConnectionRetriesLeft = $ConnectionRetries;
1443: &UpdateStatus();
1444: my $Transaction = LondTransaction->new($data);
1445: $Transaction->SetClient($socket);
1446: StartClientReply($Transaction, "ok\n");
1447: $watcher->cancel();
1448: return;
1449: }
1450: Debug(8, "Complete transaction received: ".$data);
1451: if ($LogTransactions) {
1452: Log("SUCCESS", "Transaction: '$data'"); # Transaction has \n.
1453: }
1454: my $Transaction = LondTransaction->new($data);
1455: $Transaction->SetClient($socket);
1456: QueueTransaction($Transaction);
1457: $watcher->cancel(); # Done looking for input data.
1458: }
1459:
1460: }
1461:
1462: #
1463: # Accept a connection request for a client (lonc child) and
1464: # start up an event watcher to keep an eye on input from that
1465: # Event. This can be called both from NewClient and from
1466: # ChildProcess.
1467: # Parameters:
1468: # $socket - The listener socket.
1469: # Returns:
1470: # NONE
1471: # Side Effects:
1472: # An event is made to watch the accepted connection.
1473: # Active clients hash is updated to reflect the new connection.
1474: # The client connection count is incremented.
1475: #
1476: sub accept_client {
1477: my ($socket) = @_;
1478:
1479: Debug(8, "Entering accept for lonc UNIX socket\n");
1480: my $connection = $socket->accept(); # Accept the client connection.
1481: Debug(8,"Connection request accepted from "
1482: .GetPeername($connection, AF_UNIX));
1483:
1484:
1485: my $description = sprintf("Connection to lonc client %d",
1486: $ClientConnection);
1487: Debug(9, "Creating event named: ".$description);
1488: Event->io(cb => \&ClientRequest,
1489: poll => 'r',
1490: desc => $description,
1491: data => "",
1492: fd => $connection);
1493: $ActiveClients{$connection} = $ClientConnection;
1494: $ClientConnection++;
1495: }
1496:
1497: =pod
1498:
1499: =head2 NewClient
1500:
1501: Callback that is called when a connection is received on the unix
1502: socket for a new client of lonc. The callback is parameterized by the
1503: event.. which is a-priori assumed to be an io event, and therefore has
1504: an fd member that is the Listener socket. We accept the connection
1505: and register a new event on the readability of that socket:
1506:
1507: =cut
1508:
1509: sub NewClient {
1510: Debug(6, "NewClient");
1511: my $event = shift; # Get the event parameters.
1512: my $watcher = $event->w;
1513: my $socket = $watcher->fd; # Get the event' socket.
1514:
1515: &accept_client($socket);
1516: }
1517:
1518: =pod
1519:
1520: =head2 GetLoncSocketPath
1521:
1522: Returns the name of the UNIX socket on which to listen for client
1523: connections.
1524:
1525: =head2 Parameters:
1526:
1527: host (optional) - Name of the host socket to return.. defaults to
1528: the return from GetServerHost().
1529:
1530: =cut
1531:
1532: sub GetLoncSocketPath {
1533:
1534: my $host = GetServerHost(); # Default host.
1535: if (@_) {
1536: ($host) = @_; # Override if supplied.
1537: }
1538: return $UnixSocketDir."/".$host;
1539: }
1540:
1541: =pod
1542:
1543: =head2 GetServerHost
1544:
1545: Returns the host whose lond we talk with.
1546:
1547: =cut
1548:
1549: sub GetServerHost {
1550: return $RemoteHost; # Setup by the fork.
1551: }
1552:
1553: =pod
1554:
1555: =head2 GetHostId
1556:
1557: Returns the hostid whose lond we talk with.
1558:
1559: =cut
1560:
1561: sub GetHostId {
1562: return $RemoteHostId; # Setup by the fork.
1563: }
1564:
1565: =pod
1566:
1567: =head2 GetDefHostId
1568:
1569: Returns the default hostid for the node whose lond we talk with.
1570:
1571: =cut
1572:
1573: sub GetDefHostId { # Setup by the fork.
1574: return $RemoteDefHostId;
1575: }
1576:
1577: =pod
1578:
1579: =head2 GetLoncapaRev
1580:
1581: Returns the LON-CAPA version for the node whose lond we talk with.
1582:
1583: =cut
1584:
1585: sub GetLoncapaRev {
1586: return $RemoteLoncapaRev; # Setup by the fork.
1587: }
1588:
1589: =pod
1590:
1591: =head2 GetServerPort
1592:
1593: Returns the lond port number.
1594:
1595: =cut
1596:
1597: sub GetServerPort {
1598: return $perlvar{londPort};
1599: }
1600:
1601: =pod
1602:
1603: =head2 SetupLoncListener
1604:
1605: Setup a lonc listener event. The event is called when the socket
1606: becomes readable.. that corresponds to the receipt of a new
1607: connection. The event handler established will accept the connection
1608: (creating a communications channel), that in turn will establish
1609: another event handler to subess requests.
1610:
1611: =head2 Parameters:
1612:
1613: host (optional) Name of the host to set up a unix socket to.
1614:
1615: =cut
1616:
1617: sub SetupLoncListener {
1618: my ($host,$SocketName) = @_;
1619: if (!$host) { $host = &GetServerHost(); }
1620: if (!$SocketName) { $SocketName = &GetLoncSocketPath($host); }
1621:
1622:
1623: unlink($SocketName);
1624:
1625: my $socket;
1626: unless ($socket =IO::Socket::UNIX->new(Local => $SocketName,
1627: Listen => 250,
1628: Type => SOCK_STREAM)) {
1629: if($I_am_child) {
1630: &child_exit(-1, "Failed to create a lonc listener socket");
1631: } else {
1632: die "Failed to create a lonc listner socket";
1633: }
1634: }
1635: return $socket;
1636: }
1637:
1638: #
1639: # Toggle transaction logging.
1640: # Implicit inputs:
1641: # LogTransactions
1642: # Implicit Outputs:
1643: # LogTransactions
1644: sub ToggleTransactionLogging {
1645: print STDERR "Toggle transaction logging...\n";
1646: if(!$LogTransactions) {
1647: $LogTransactions = 1;
1648: } else {
1649: $LogTransactions = 0;
1650: }
1651:
1652:
1653: Log("SUCCESS", "Toggled transaction logging: $LogTransactions \n");
1654: }
1655:
1656: =pod
1657:
1658: =head2 ChildStatus
1659:
1660: Child USR1 signal handler to report the most recent status
1661: into the status file.
1662:
1663: We also use this to reset the retries count in order to allow the
1664: client to retry connections with a previously dead server.
1665:
1666: =cut
1667:
1668: sub ChildStatus {
1669: my $event = shift;
1670: my $watcher = $event->w;
1671:
1672: Debug(2, "Reporting child status because : ".$watcher->data);
1673: my $docdir = $perlvar{'lonDocRoot'};
1674:
1675: open(LOG,">>$docdir/lon-status/loncstatus.txt");
1676: flock(LOG,LOCK_EX);
1677: print LOG $$."\t".$RemoteHost."\t".$Status."\t".
1678: $RecentLogEntry."\n";
1679: #
1680: # Write out information about each of the connections:
1681: #
1682: if ($DebugLevel > 2) {
1683: print LOG "Active connection statuses: \n";
1684: my $i = 1;
1685: print STDERR "================================= Socket Status Dump:\n";
1686: foreach my $item (keys %ActiveConnections) {
1687: my $Socket = $ActiveConnections{$item}->data;
1688: my $state = $Socket->GetState();
1689: print LOG "Connection $i State: $state\n";
1690: print STDERR "---------------------- Connection $i \n";
1691: $Socket->Dump(-1); # Ensure it gets dumped..
1692: $i++;
1693: }
1694: }
1695: flock(LOG,LOCK_UN);
1696: close(LOG);
1697: $ConnectionRetriesLeft = $ConnectionRetries;
1698: UpdateStatus();
1699: }
1700:
1701: =pod
1702:
1703: =head2 SignalledToDeath
1704:
1705: Called in response to a signal that causes a chid process to die.
1706:
1707: =cut
1708:
1709:
1710: sub SignalledToDeath {
1711: my $event = shift;
1712: my $watcher= $event->w;
1713:
1714: Debug(2,"Signalled to death! via ".$watcher->data);
1715: my ($signal) = $watcher->data;
1716: chomp($signal);
1717: Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "
1718: ."died through "."\"$signal\"");
1719: #LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
1720: # ."\"$signal\"");
1721: &clear_childpid($$);
1722: exit 0;
1723:
1724: }
1725:
1726: =pod
1727:
1728: =head2 ToggleDebug
1729:
1730: This sub toggles trace debugging on and off.
1731:
1732: =cut
1733:
1734: sub ToggleDebug {
1735: my $Current = $DebugLevel;
1736: $DebugLevel = $NextDebugLevel;
1737: $NextDebugLevel = $Current;
1738:
1739: Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
1740:
1741: }
1742:
1743: =pod
1744:
1745: =head2 ChildProcess
1746:
1747: This sub implements a child process for a single lonc daemon.
1748: Optional parameter:
1749: $socket - if provided, this is a socket already open for listening
1750: on the client socket. Otherwise, a new listener is set up.
1751:
1752: =cut
1753:
1754: sub ChildProcess {
1755: # We've inherited all the
1756: # events of our parent and those have to be cancelled or else
1757: # all holy bloody chaos will result.. trust me, I already made
1758: # >that< mistake.
1759:
1760: my $host = GetServerHost();
1761: foreach my $listener (keys %parent_dispatchers) {
1762: my $watcher = $parent_dispatchers{$listener};
1763: my $s = $watcher->fd;
1764: if ($listener ne $host) { # Close everyone but me.
1765: Debug(5, "Closing listen socket for $listener");
1766: $s->close();
1767: }
1768: Debug(5, "Killing watcher for $listener");
1769:
1770: $watcher->cancel();
1771: delete($parent_dispatchers{$listener});
1772:
1773: }
1774:
1775: # kill off the parent's signal handlers too!
1776: #
1777:
1778: for my $handler (keys %parent_handlers) {
1779: my $watcher = $parent_handlers{$handler};
1780: $watcher->cancel();
1781: delete($parent_handlers{$handler});
1782: }
1783:
1784: $I_am_child = 1; # Seems like in spite of it all I may still getting
1785: # parent event dispatches.. flag I'm a child.
1786:
1787:
1788: #
1789: # Signals must be handled by the Event framework...
1790: #
1791:
1792: Event->signal(signal => "QUIT",
1793: cb => \&SignalledToDeath,
1794: data => "QUIT");
1795: Event->signal(signal => "HUP",
1796: cb => \&ChildStatus,
1797: data => "HUP");
1798: Event->signal(signal => "USR1",
1799: cb => \&ChildStatus,
1800: data => "USR1");
1801: Event->signal(signal => "USR2",
1802: cb => \&ToggleTransactionLogging);
1803: Event->signal(signal => "INT",
1804: cb => \&ToggleDebug,
1805: data => "INT");
1806:
1807: # Block the pipe signal we'll get when the socket disconnects. We detect
1808: # socket disconnection via send/receive failures. On disconnect, the
1809: # socket becomes readable .. which will force the disconnect detection.
1810:
1811: my $set = POSIX::SigSet->new(SIGPIPE);
1812: sigprocmask(SIG_BLOCK, $set);
1813:
1814: # Figure out if we got passed a socket or need to open one to listen for
1815: # client requests.
1816:
1817: my ($socket) = @_;
1818: if (!$socket) {
1819:
1820: $socket = SetupLoncListener();
1821: }
1822: # Establish an event to listen for client connection requests.
1823:
1824:
1825: Event->io(cb => \&NewClient,
1826: poll => 'r',
1827: desc => 'Lonc Listener Unix Socket',
1828: fd => $socket);
1829:
1830: $Event::DebugLevel = $DebugLevel;
1831:
1832: Debug(9, "Making initial lond connection for ".$RemoteHost);
1833:
1834: # Setup the initial server connection:
1835:
1836: # &MakeLondConnection(); // let first work request do it.
1837:
1838: # need to accept the connection since the event may not fire.
1839:
1840: &accept_client($socket);
1841:
1842: Debug(9,"Entering event loop");
1843: my $ret = Event::loop(); # Start the main event loop.
1844:
1845:
1846: &child_exit (-1,"Main event loop exited!!!");
1847: }
1848:
1849: # Create a new child for host passed in:
1850:
1851: sub CreateChild {
1852: my ($host, $hostid, $defhostid, $loncaparev) = @_;
1853:
1854: my $sigset = POSIX::SigSet->new(SIGINT);
1855: sigprocmask(SIG_BLOCK, $sigset);
1856: $RemoteHost = $host;
1857: ShowStatus('Parent keeping the flock'); # Update time in status message.
1858: Log("CRITICAL", "Forking server for ".$host);
1859: my $pid = fork;
1860: if($pid) { # Parent
1861: $RemoteHost = "Parent";
1862: $ChildPid{$pid} = $host;
1863: sigprocmask(SIG_UNBLOCK, $sigset);
1864: undef(@all_host_ids);
1865: } else { # child.
1866: $RemoteHostId = $hostid;
1867: $RemoteDefHostId = $defhostid;
1868: $RemoteLoncapaRev = $loncaparev;
1869: ShowStatus("Connected to ".$RemoteHost);
1870: $SIG{INT} = 'DEFAULT';
1871: sigprocmask(SIG_UNBLOCK, $sigset);
1872: &ChildProcess(); # Does not return.
1873: }
1874: }
1875:
1876: # parent_client_connection:
1877: # Event handler that processes client connections for the parent process.
1878: # This sub is called when the parent is listening on a socket and
1879: # a connection request arrives. We must:
1880: # Start a child process to accept the connection request.
1881: # Kill our listen on the socket.
1882: # Parameter:
1883: # event - The event object that was created to monitor this socket.
1884: # event->w->fd is the socket.
1885: # Returns:
1886: # NONE
1887: #
1888: sub parent_client_connection {
1889: if ($I_am_child) {
1890: # Should not get here, but seem to anyway:
1891: &Debug(5," Child caught parent client connection event!!");
1892: my ($event) = @_;
1893: my $watcher = $event->w;
1894: $watcher->cancel(); # Try to kill it off again!!
1895: } else {
1896: &Debug(9, "parent_client_connection");
1897: my ($event) = @_;
1898: my $watcher = $event->w;
1899: my $socket = $watcher->fd;
1900: my $connection = $socket->accept(); # Accept the client connection.
1901: Event->io(cb => \&get_remote_hostname,
1902: poll => 'r',
1903: data => "",
1904: fd => $connection);
1905: }
1906: }
1907:
1908: sub get_remote_hostname {
1909: my ($event) = @_;
1910: my $watcher = $event->w;
1911: my $socket = $watcher->fd;
1912:
1913: my $thisread;
1914: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1915: Debug(8, "rcv: data length = ".length($thisread)." read =".$thisread);
1916: if (!defined($rv) || length($thisread) == 0) {
1917: # Likely eof on socket.
1918: Debug(5,"Client Socket closed on lonc for p_c_c");
1919: close($socket);
1920: $watcher->cancel();
1921: return;
1922: }
1923:
1924: my $data = $watcher->data().$thisread;
1925: $watcher->data($data);
1926: if($data =~ /\n$/) { # Request entirely read.
1927: chomp($data);
1928: } else {
1929: return;
1930: }
1931:
1932: &Debug(5,"Creating child for $data (parent_client_connection)");
1933: (my $hostname,my $lonid,@all_host_ids) = split(':',$data);
1934: $ChildHost{$hostname}++;
1935: if ($ChildHost{$hostname} == 1) {
1936: &CreateChild($hostname,$lonid,$all_host_ids[-1]);
1937: } else {
1938: &Log('WARNING',"Request for a second child on $hostname");
1939: }
1940: # Clean up the listen since now the child takes over until it exits.
1941: $watcher->cancel(); # Nolonger listening to this event
1942: $socket->send("done\n");
1943: $socket->close();
1944: }
1945:
1946: # parent_listen:
1947: # Opens a socket and starts a listen for the parent process on a client UNIX
1948: # domain socket.
1949: #
1950: # This involves:
1951: # Creating a socket for listen.
1952: # Removing any socket lock file
1953: # Adding an event handler for this socket becoming readable
1954: # To the parent's event dispatcher.
1955: # Parameters:
1956: # loncapa_host - LonCAPA cluster name of the host represented by the client
1957: # socket.
1958: # Returns:
1959: # NONE
1960: #
1961: sub parent_listen {
1962: my ($loncapa_host) = @_;
1963: Debug(5, "parent_listen: $loncapa_host");
1964:
1965: my ($socket,$file);
1966: if (!$loncapa_host) {
1967: $loncapa_host = 'common_parent';
1968: $file = $perlvar{'lonSockCreate'};
1969: } else {
1970: $file = &GetLoncSocketPath($loncapa_host);
1971: }
1972: $socket = &SetupLoncListener($loncapa_host,$file);
1973:
1974: $listening_to{$socket} = $loncapa_host;
1975: if (!$socket) {
1976: die "Unable to create a listen socket for $loncapa_host";
1977: }
1978:
1979: my $lock_file = $file.".lock";
1980: unlink($lock_file); # No problem if it doesn't exist yet [startup e.g.]
1981:
1982: my $watcher =
1983: Event->io(cb => \&parent_client_connection,
1984: poll => 'r',
1985: desc => "Parent listener unix socket ($loncapa_host)",
1986: data => "",
1987: fd => $socket);
1988: $parent_dispatchers{$loncapa_host} = $watcher;
1989:
1990: }
1991:
1992: sub parent_clean_up {
1993: my ($loncapa_host) = @_;
1994: Debug(1, "parent_clean_up: $loncapa_host");
1995:
1996: my $socket_file = &GetLoncSocketPath($loncapa_host);
1997: unlink($socket_file); # No problem if it doesn't exist yet [startup e.g.]
1998: my $lock_file = $socket_file.".lock";
1999: unlink($lock_file); # No problem if it doesn't exist yet [startup e.g.]
2000: }
2001:
2002:
2003:
2004: # This sub initiates a listen on the common unix domain lonc client socket.
2005: # loncnew starts up with no children, and only spawns off children when a
2006: # connection request occurs on the common client unix socket. The spawned
2007: # child continues to run until it has been idle a while at which point it
2008: # eventually exits and once more the parent picks up the listen.
2009: #
2010: # Parameters:
2011: # NONE
2012: # Implicit Inputs:
2013: # The configuration file that has been read in by LondConnection.
2014: # Returns:
2015: # NONE
2016: #
2017: sub listen_on_common_socket {
2018: Debug(5, "listen_on_common_socket");
2019: &parent_listen();
2020: }
2021:
2022: # server_died is called whenever a child process exits.
2023: # Since this is dispatched via a signal, we must process all
2024: # dead children until there are no more left. The action
2025: # is to:
2026: # - Remove the child from the bookeeping hashes
2027: # - Re-establish a listen on the unix domain socket associated
2028: # with that host.
2029: # Parameters:
2030: # The event, but we don't actually care about it.
2031: sub server_died {
2032: &Debug(9, "server_died called...");
2033:
2034: while(1) { # Loop until waitpid nowait fails.
2035: my $pid = waitpid(-1, WNOHANG);
2036: if($pid <= 0) {
2037: return; # Nothing left to wait for.
2038: }
2039: # need the host to restart:
2040:
2041: my $host = $ChildPid{$pid};
2042: if($host) { # It's for real...
2043: &Debug(9, "Caught sigchild for $host");
2044: &clear_childpid($pid);
2045: delete($ChildPid{$pid});
2046: delete($ChildHost{$host});
2047: &parent_clean_up($host);
2048:
2049: } else {
2050: &Debug(5, "Caught sigchild for pid not in hosts hash: $pid");
2051: }
2052: }
2053:
2054: }
2055:
2056: #
2057: # Parent process logic pass 1:
2058: # For each entry in the hosts table, we will
2059: # fork off an instance of ChildProcess to service the transactions
2060: # to that host. Each pid will be entered in a global hash
2061: # with the value of the key, the host.
2062: # The parent will then enter a loop to wait for process exits.
2063: # Each exit gets logged and the child gets restarted.
2064: #
2065:
2066: #
2067: # Fork and start in new session so hang-up isn't going to
2068: # happen without intent.
2069: #
2070:
2071:
2072:
2073:
2074:
2075:
2076: ShowStatus("Forming new session");
2077: my $childpid = fork;
2078: if ($childpid != 0) {
2079: sleep 4; # Give child a chacne to break to
2080: exit 0; # a new sesion.
2081: }
2082: #
2083: # Write my pid into the pid file so I can be located
2084: #
2085:
2086: ShowStatus("Parent writing pid file:");
2087: my $execdir = $perlvar{'lonDaemons'};
2088: open (PIDSAVE, ">$execdir/logs/lonc.pid");
2089: print PIDSAVE "$$\n";
2090: close(PIDSAVE);
2091:
2092:
2093:
2094: if (POSIX::setsid() < 0) {
2095: print "Could not create new session\n";
2096: exit -1;
2097: }
2098:
2099: ShowStatus("Forking node servers");
2100:
2101: Log("CRITICAL", "--------------- Starting children ---------------");
2102:
2103: LondConnection::ReadConfig; # Read standard config files.
2104:
2105: $RemoteHost = "[parent]";
2106: &listen_on_common_socket();
2107:
2108: $RemoteHost = "Parent Server";
2109:
2110: # Maintain the population:
2111:
2112: ShowStatus("Parent keeping the flock");
2113:
2114:
2115: # We need to setup a SIGChild event to handle the exit (natural or otherwise)
2116: # of the children.
2117:
2118: Event->signal(cb => \&server_died,
2119: desc => "Child exit handler",
2120: signal => "CHLD");
2121:
2122:
2123: # Set up all the other signals we set up.
2124:
2125: $parent_handlers{INT} = Event->signal(cb => \&Terminate,
2126: desc => "Parent INT handler",
2127: signal => "INT");
2128: $parent_handlers{TERM} = Event->signal(cb => \&Terminate,
2129: desc => "Parent TERM handler",
2130: signal => "TERM");
2131: $parent_handlers{HUP} = Event->signal(cb => \&KillThemAll,
2132: desc => "Parent HUP handler.",
2133: signal => "HUP");
2134: $parent_handlers{USR1} = Event->signal(cb => \&CheckKids,
2135: desc => "Parent USR1 handler",
2136: signal => "USR1");
2137: $parent_handlers{USR2} = Event->signal(cb => \&UpdateKids,
2138: desc => "Parent USR2 handler.",
2139: signal => "USR2");
2140:
2141: # Start procdesing events.
2142:
2143: $Event::DebugLevel = $DebugLevel;
2144: Debug(9, "Parent entering event loop");
2145: my $ret = Event::loop();
2146: die "Main Event loop exited: $ret";
2147:
2148: =pod
2149:
2150: =head1 CheckKids
2151:
2152: Since kids do not die as easily in this implementation
2153: as the previous one, there is no need to restart the
2154: dead ones (all dead kids get restarted when they die!!)
2155: The only thing this function does is to pass USR1 to the
2156: kids so that they report their status.
2157:
2158: =cut
2159:
2160: sub CheckKids {
2161: Debug(2, "Checking status of children");
2162: my $docdir = $perlvar{'lonDocRoot'};
2163: my $fh = IO::File->new(">$docdir/lon-status/loncstatus.txt");
2164: my $now=time;
2165: my $local=localtime($now);
2166: print $fh "LONC status $local - parent $$ \n\n";
2167: foreach my $host (keys %parent_dispatchers) {
2168: print $fh "LONC Parent process listening for $host\n";
2169: }
2170: foreach my $pid (keys %ChildPid) {
2171: Debug(2, "Sending USR1 -> $pid");
2172: kill 'USR1' => $pid; # Tell Child to report status.
2173: }
2174:
2175: }
2176:
2177: =pod
2178:
2179: =head1 UpdateKids
2180:
2181: parent's SIGUSR2 handler. This handler:
2182:
2183: =item
2184:
2185: Rereads the hosts file.
2186:
2187: =item
2188:
2189: Kills off (via sigint) children for hosts that have disappeared.
2190:
2191: =item
2192:
2193: QUITs children for hosts that already exist (this just forces a status display
2194: and resets the connection retry count for that host.
2195:
2196: =item
2197:
2198: Starts new children for hosts that have been added to the hosts.tab file since
2199: the start of the master program and maintains them.
2200:
2201: =cut
2202:
2203: sub UpdateKids {
2204:
2205: Log("INFO", "Updating connections via SIGUSR2");
2206:
2207: # I'm not sure what I was thinking in the first implementation.
2208: # someone will have to work hard to convince me the effect is any
2209: # different than Restart, especially now that we don't start up
2210: # per host servers automatically, may as well just restart.
2211: # The down side is transactions that are in flight will get timed out
2212: # (lost unless they are critical).
2213:
2214: &KillThemAll();
2215: LondConnection->ResetReadConfig();
2216: ShowStatus('Parent keeping the flock');
2217: }
2218:
2219:
2220: =pod
2221:
2222: =head1 Restart
2223:
2224: Signal handler for HUP... all children are killed and
2225: we self restart. This is an el-cheapo way to re-read
2226: the config file.
2227:
2228: =cut
2229:
2230: sub Restart {
2231: &KillThemAll; # First kill all the children.
2232: LondConnection->ResetReadConfig();
2233: Log("CRITICAL", "Restarting");
2234: my $execdir = $perlvar{'lonDaemons'};
2235: unlink("$execdir/logs/lonc.pid");
2236: exec("$executable");
2237: }
2238:
2239: =pod
2240:
2241: =head1 KillThemAll
2242:
2243: Signal handler that kills all children by sending them a
2244: SIGHUP. Responds to sigint and sigterm.
2245:
2246: =cut
2247:
2248: sub KillThemAll {
2249: Debug(2, "Kill them all!!");
2250:
2251: #local($SIG{CHLD}) = 'IGNORE';
2252: # Our children >will< die.
2253: # but we need to catch their death and cleanup after them in case this is
2254: # a restart set of kills
2255: my @allpids = keys(%ChildPid);
2256: foreach my $pid (@allpids) {
2257: my $serving = $ChildPid{$pid};
2258: ShowStatus("Nicely Killing lonc for $serving pid = $pid");
2259: Log("CRITICAL", "Nicely Killing lonc for $serving pid = $pid");
2260: kill 'QUIT' => $pid;
2261: &clear_childpid($pid);
2262: }
2263: ShowStatus("Finished killing child processes off.");
2264: }
2265:
2266:
2267: #
2268: # Kill all children via KILL. Just in case the
2269: # first shot didn't get them.
2270:
2271: sub really_kill_them_all_dammit
2272: {
2273: Debug(2, "Kill them all Dammit");
2274: local($SIG{CHLD} = 'IGNORE'); # In case some purist reenabled them.
2275: foreach my $pid (keys %ChildPid) {
2276: my $serving = $ChildPid{$pid};
2277: &ShowStatus("Nastily killing lonc for $serving pid = $pid");
2278: Log("CRITICAL", "Nastily killing lonc for $serving pid = $pid");
2279: kill 'KILL' => $pid;
2280: delete($ChildPid{$pid});
2281: delete($ChildKeyMode{$pid});
2282: my $execdir = $perlvar{'lonDaemons'};
2283: unlink("$execdir/logs/lonc.pid");
2284: }
2285: }
2286:
2287: =pod
2288:
2289: =head1 Terminate
2290:
2291: Terminate the system.
2292:
2293: =cut
2294:
2295: sub Terminate {
2296: &Log("CRITICAL", "Asked to kill children.. first be nice...");
2297: &KillThemAll;
2298: #
2299: # By now they really should all be dead.. but just in case
2300: # send them all SIGKILL's after a bit of waiting:
2301:
2302: sleep(4);
2303: &Log("CRITICAL", "Now kill children nasty");
2304: &really_kill_them_all_dammit;
2305: Log("CRITICAL","Master process exiting");
2306: exit 0;
2307:
2308: }
2309:
2310: =pod
2311:
2312: =cut
2313:
2314: sub my_hostname {
2315: use Sys::Hostname::FQDN();
2316: my $name = Sys::Hostname::FQDN::fqdn();
2317: &Debug(9,"Name is $name");
2318: return $name;
2319: }
2320:
2321: sub record_childpid {
2322: my ($Socket) = @_;
2323: my $docdir = $perlvar{'lonDocRoot'};
2324: my $authmode = $Socket->GetKeyMode();
2325: my $peer = $Socket->PeerLoncapaHim();
2326: if (($authmode eq 'ssl') || ($authmode eq 'insecure')) {
2327: my $childpid = $$;
2328: if ($childpid) {
2329: unless (exists($ChildKeyMode{$childpid})) {
2330: $ChildKeyMode{$childpid} = $authmode;
2331: }
2332: if (-d "$docdir/lon-status/loncchld") {
2333: unless (-e "$docdir/lon-status/loncchld/$childpid") {
2334: if (open (my $pidfh,'>',"$docdir/lon-status/loncchld/$childpid")) {
2335: print $pidfh "$peer:$authmode\n";
2336: close($pidfh);
2337: }
2338: }
2339: }
2340: }
2341: }
2342: return;
2343: }
2344:
2345: sub clear_childpid {
2346: my ($childpid) = @_;
2347: my $docdir = $perlvar{'lonDocRoot'};
2348: if (-d "$docdir/lon-status/loncchld") {
2349: if ($childpid =~ /^\d+$/) {
2350: if (($ChildKeyMode{$childpid} eq 'insecure') ||
2351: ($ChildKeyMode{$childpid} eq 'ssl')) {
2352: if (-e "$docdir/lon-status/loncchld/$childpid") {
2353: unlink("$docdir/lon-status/loncchld/$childpid");
2354: }
2355: }
2356: }
2357: }
2358: if (exists($ChildKeyMode{$childpid})) {
2359: delete($ChildKeyMode{$childpid});
2360: }
2361: return;
2362: }
2363:
2364: =pod
2365:
2366: =head1 Theory
2367:
2368: The event class is used to build this as a single process with an
2369: event driven model. The following events are handled:
2370:
2371: =item UNIX Socket connection Received
2372:
2373: =item Request data arrives on UNIX data transfer socket.
2374:
2375: =item lond connection becomes writable.
2376:
2377: =item timer fires at 1 second intervals.
2378:
2379: All sockets are run in non-blocking mode. Timeouts managed by the timer
2380: handler prevents hung connections.
2381:
2382: Key data structures:
2383:
2384: =item RequestQueue
2385:
2386: A queue of requests received from UNIX sockets that are
2387: waiting for a chance to be forwarded on a lond connection socket.
2388:
2389: =item ActiveConnections
2390:
2391: A hash of lond connections that have transactions in process that are
2392: available to be timed out.
2393:
2394: =item ActiveTransactions
2395:
2396: A hash indexed by lond connections that contain the client reply
2397: socket for each connection that has an active transaction on it.
2398:
2399: =item IdleConnections
2400:
2401: A hash of lond connections that have no work to do. These connections
2402: can be closed if they are idle for a long enough time.
2403:
2404: =cut
2405:
2406: =pod
2407:
2408: =head1 Log messages
2409:
2410: The following is a list of log messages that can appear in the
2411: lonc.log file. Each log file has a severity and a message.
2412:
2413: =over 2
2414:
2415: =item Warning A socket timeout was detected
2416:
2417: If there are pending transactions in the socket's queue,
2418: they are failed (saved if critical). If the connection
2419: retry count gets exceeded by this, the
2420: remote host is marked as dead.
2421: Called when timeouts occurred during the connection and
2422: connection dialog with a remote host.
2423:
2424: =item Critical Host makred DEAD <hostname>
2425:
2426: The numer of retry counts for contacting a host was
2427: exceeded. The host is marked dead an no
2428: further attempts will be made by that child.
2429:
2430: =item Info lonc pipe client hung up on us
2431:
2432: Write to the client pipe indicated no data transferred
2433: Socket to remote host is shut down. Reply to the client
2434: is discarded. Note: This is commented out in &ClientWriteable
2435:
2436: =item Success Reply from lond: <data>
2437:
2438: Can be enabled for debugging by setting LogTransactions to nonzero.
2439: Indicates a successful transaction with lond, <data> is the data received
2440: from the remote lond.
2441:
2442: =item Success A delayed transaction was completed
2443:
2444: A transaction that must be reliable was executed and completed
2445: as lonc restarted. This is followed by a mesage of the form
2446:
2447: S: client-name : request
2448:
2449: =item WARNING Failing transaction <cmd>:<subcmd>
2450:
2451: Transaction failed on a socket, but the failure retry count for the remote
2452: node has not yet been exhausted (the node is not yet marked dead).
2453: cmd is the command, subcmd is the subcommand. This results from a con_lost
2454: when communicating with lond.
2455:
2456: =item WARNING Shutting down a socket
2457:
2458: Called when a socket is being closed to lond. This is emitted both when
2459: idle pruning is being done and when the socket has been disconnected by the remote.
2460:
2461: =item WARNING Lond connection lost.
2462:
2463: Called when a read from lond's socket failed indicating lond has closed the
2464: connection or died. This should be followed by one or more
2465:
2466: "WARNING Failing transaction..." msgs for each in-flight or queued transaction.
2467:
2468: =item WARNING No SSL channel (verification failed), will try with insecure channel.
2469:
2470: Called when promotion of a socket to SSL failed because SSL certificate verification failed.
2471: Domain configuration must also permit insecure channel use for key exchange. Connection
2472: negotiation will start again from the beginning, but with Authentication Mode not set to ssl.
2473:
2474: =item INFO Connected to lond version: <version>
2475:
2476: When connection negotiation is complete, the lond version is requested and logged here.
2477:
2478: =item SUCCESS Connection n to host now ready for action
2479:
2480: Emitted when connection has been completed with lond. n is then number of
2481: concurrent connections and host, the host to which the connection has just
2482: been established.
2483:
2484: =item WARNING Connection to host has been disconnected
2485:
2486: Write to a lond resulted in failure status. Connection to lond is dropped.
2487:
2488: =item SUCCESS Created connection n to host host
2489:
2490: Initial connection request to host..(before negotiation).
2491:
2492: =item CRITICAL Request Close Connection ... exiting
2493:
2494: Client has sent "close_connection_exit" The loncnew server is exiting.
2495:
2496: =item INFO Resetting Connection Retries
2497:
2498: Client has sent "reset_retries" The lond connection retries are reset to zero for the
2499: corresponding lond.
2500:
2501: =item SUCCESS Transaction <data>
2502:
2503: Only emitted if the global variable $LogTransactions was set to true.
2504: A client has requested a lond transaction <data> is the contents of the request.
2505:
2506: =item SUCCESS Toggled transaction logging <LogTransactions>
2507:
2508: The state of the $LogTransactions global has been toggled, and its current value
2509: (after being toggled) is displayed. When non zero additional logging of transactions
2510: is enabled for debugging purposes. Transaction logging is toggled on receipt of a USR2
2511: signal.
2512:
2513: =item CRITICAL Abnormal exit. Child <pid> for <host> died thorugh signal.
2514:
2515: QUIT signal received. lonc child process is exiting.
2516:
2517: =item SUCCESS New debugging level for <RemoteHost> now <DebugLevel>
2518:
2519: Debugging toggled for the host loncnew is talking with.
2520: Currently debugging is a level based scheme with higher number
2521: conveying more information. The daemon starts out at
2522: DebugLevel 0 and can toggle back and forth between that and
2523: DebugLevel 2 These are controlled by
2524: the global variables $DebugLevel and $NextDebugLevel
2525: The debug level can go up to 9.
2526: SIGINT toggles the debug level. The higher the debug level the
2527: more debugging information is spewed. See the Debug
2528: sub in loncnew.
2529:
2530: =item CRITICAL Forking server for host
2531:
2532: A child is being created to service requests for the specified host.
2533:
2534:
2535: =item WARNING Request for a second child on hostname
2536:
2537: Somehow loncnew was asked to start a second child on a host that already had a child
2538: servicing it. This request is not honored, but themessage is emitted. This could happen
2539: due to a race condition. When a client attempts to contact loncnew for a new host, a child
2540: is forked off to handle the requests for that server. The parent then backs off the Unix
2541: domain socket leaving it for the child to service all requests. If in the time between
2542: creating the child, and backing off, a new connection request comes in to the unix domain
2543: socket, this could trigger (unlikely but remotely possible),.
2544:
2545: =item CRITICAL ------ Starting Children ----
2546:
2547: This message should probably be changed to "Entering event loop" as the loncnew only starts
2548: children as needed. This message is emitted as new events are established and
2549: the event processing loop is entered.
2550:
2551: =item INFO Updating connections via SIGUSR2
2552:
2553: SIGUSR2 received. The original code would kill all clients, re-read the host file,
2554: then restart children for each host. Now that children are started on demand, this
2555: just kills all child processes and lets requests start them as needed again.
2556:
2557:
2558: =item CRITICAL Restarting
2559:
2560: SigHUP received. all the children are killed and the script exec's itself to start again.
2561:
2562: =item CRITICAL Nicely killing lonc for host pid = <pid>
2563:
2564: Attempting to kill the child that is serving the specified host (pid given) cleanly via
2565: SIGQUIT. The child should handle that, clean up nicely and exit.
2566:
2567: =item CRITICAL Nastily killing lonc for host pid = <pid>
2568:
2569: The child specified did not die when requested via SIGQUIT. Therefore it is killed
2570: via SIGKILL.
2571:
2572: =item CRITICAL Asked to kill children.. first be nice..
2573:
2574: In the parent's INT handler. INT kills the child processes. This inidicate loncnew
2575: is about to attempt to kill all known children via SIGQUIT. This message should be followed
2576: by one "Nicely killing" message for each extant child.
2577:
2578: =item CRITICAL Now kill children nasty
2579:
2580: In the parent's INT handler. remaining children are about to be killed via
2581: SIGKILL. Should be followed by a Nastily killing... for each lonc child that
2582: refused to die.
2583:
2584: =item CRITICAL Master process exiting
2585:
2586: In the parent's INT handler. just prior to the exit 0 call.
2587:
2588: =back
2589:
2590: =cut
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