1: #!/usr/bin/perl
2: # The LearningOnline Network with CAPA
3: # lonc maintains the connections to remote computers
4: #
5: # $Id: loncnew,v 1.79 2007/03/28 00:14:15 albertel Exp $
6: #
7: # Copyright Michigan State University Board of Trustees
8: #
9: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
10: ## LON-CAPA is free software; you can redistribute it and/or modify
11: # it under the terms of the GNU General Public License as published by
12: # the Free Software Foundation; either version 2 of the License, or
13: # (at your option) any later version.
14: #
15: # LON-CAPA is distributed in the hope that it will be useful,
16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18: # GNU General Public License for more details.
19: #
20: # You should have received a copy of the GNU General Public License
21: # along with LON-CAPA; if not, write to the Free Software
22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23: #
24: # /home/httpd/html/adm/gpl.txt
25: #
26: # http://www.lon-capa.org/
27: #
28: #
29: # new lonc handles n request out bver m connections to londs.
30: # This module is based on the Event class.
31: # Development iterations:
32: # - Setup basic event loop. (done)
33: # - Add timer dispatch. (done)
34: # - Add ability to accept lonc UNIX domain sockets. (done)
35: # - Add ability to create/negotiate lond connections (done).
36: # - Add general logic for dispatching requests and timeouts. (done).
37: # - Add support for the lonc/lond requests. (done).
38: # - Add logging/status monitoring. (done)
39: # - Add Signal handling - HUP restarts. USR1 status report. (done)
40: # - Add Configuration file I/O (done).
41: # - Add management/status request interface. (done)
42: # - Add deferred request capability. (done)
43: # - Detect transmission timeouts. (done)
44: #
45:
46: use strict;
47: use lib "/home/httpd/lib/perl/";
48: use Event qw(:DEFAULT );
49: use POSIX qw(:signal_h);
50: use POSIX;
51: use IO::Socket;
52: use IO::Socket::INET;
53: use IO::Socket::UNIX;
54: use IO::File;
55: use IO::Handle;
56: use Socket;
57: use Crypt::IDEA;
58: use LONCAPA::Queue;
59: use LONCAPA::Stack;
60: use LONCAPA::LondConnection;
61: use LONCAPA::LondTransaction;
62: use LONCAPA::Configuration;
63: use LONCAPA::HashIterator;
64: use Fcntl qw(:flock);
65:
66:
67: # Read the httpd configuration file to get perl variables
68: # normally set in apache modules:
69:
70: my $perlvarref = LONCAPA::Configuration::read_conf('loncapa.conf');
71: my %perlvar = %{$perlvarref};
72:
73: #
74: # parent and shared variables.
75:
76: my %ChildHash; # by pid -> host.
77: my %HostToPid; # By host -> pid.
78: my %HostHash; # by loncapaname -> IP.
79: my %listening_to; # Socket->host table for who the parent
80: # is listening to.
81: my %parent_dispatchers; # host-> listener watcher events.
82:
83: my %parent_handlers; # Parent signal handlers...
84:
85: my $MaxConnectionCount = 10; # Will get from config later.
86: my $ClientConnection = 0; # Uniquifier for client events.
87:
88: my $DebugLevel = 0;
89: my $NextDebugLevel= 2; # So Sigint can toggle this.
90: my $IdleTimeout= 600; # Wait 10 minutes before pruning connections.
91:
92: my $LogTransactions = 0; # When True, all transactions/replies get logged.
93: my $executable = $0; # Get the full path to me.
94:
95: #
96: # The variables below are only used by the child processes.
97: #
98: my $RemoteHost; # Name of host child is talking to.
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 $DieWhenIdle = 1; # When true children die when trimmed -> 0.
118: my $hosts_tab = 0; # True if we are using a static hosts.tab
119: my $I_am_child = 0; # True if this is the child process.
120:
121: #
122: # The hash below gives the HTML format for log messages
123: # given a severity.
124: #
125: my %LogFormats;
126:
127: $LogFormats{"CRITICAL"} = "<font color='red'>CRITICAL: %s</font>";
128: $LogFormats{"SUCCESS"} = "<font color='green'>SUCCESS: %s</font>";
129: $LogFormats{"INFO"} = "<font color='yellow'>INFO: %s</font>";
130: $LogFormats{"WARNING"} = "<font color='blue'>WARNING: %s</font>";
131: $LogFormats{"DEFAULT"} = " %s ";
132:
133:
134: # UpdateStatus;
135: # Update the idle status display to show how many connections
136: # are left, retries and other stuff.
137: #
138: sub UpdateStatus {
139: if ($ConnectionRetriesLeft > 0) {
140: ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
141: ." Retries remaining: ".$ConnectionRetriesLeft
142: ." ($KeyMode)");
143: } else {
144: ShowStatus(GetServerHost()." >> DEAD <<");
145: }
146: }
147:
148:
149: =pod
150:
151: =head2 LogPerm
152:
153: Makes an entry into the permanent log file.
154:
155: =cut
156:
157: sub LogPerm {
158: my $message=shift;
159: my $execdir=$perlvar{'lonDaemons'};
160: my $now=time;
161: my $local=localtime($now);
162: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
163: print $fh "$now:$message:$local\n";
164: }
165:
166: =pod
167:
168: =head2 Log
169:
170: Logs a message to the log file.
171: Parameters:
172:
173: =item severity
174:
175: One of CRITICAL, WARNING, INFO, SUCCESS used to select the
176: format string used to format the message. if the severity is
177: not a defined severity the Default format string is used.
178:
179: =item message
180:
181: The base message. In addtion to the format string, the message
182: will be appended to a string containing the name of our remote
183: host and the time will be formatted into the message.
184:
185: =cut
186:
187: sub Log {
188:
189: my ($severity, $message) = @_;
190:
191: if(!$LogFormats{$severity}) {
192: $severity = "DEFAULT";
193: }
194:
195: my $format = $LogFormats{$severity};
196:
197: # Put the window dressing in in front of the message format:
198:
199: my $now = time;
200: my $local = localtime($now);
201: my $finalformat = "$local ($$) [$RemoteHost] [$Status] ";
202: $finalformat = $finalformat.$format."\n";
203:
204: # open the file and put the result.
205:
206: my $execdir = $perlvar{'lonDaemons'};
207: my $fh = IO::File->new(">>$execdir/logs/lonc.log");
208: my $msg = sprintf($finalformat, $message);
209: $RecentLogEntry = $msg;
210: print $fh $msg;
211:
212:
213: }
214:
215:
216: =pod
217:
218: =head2 GetPeerName
219:
220: Returns the name of the host that a socket object is connected to.
221:
222: =cut
223:
224: sub GetPeername {
225:
226:
227: my ($connection, $AdrFamily) = @_;
228:
229: my $peer = $connection->peername();
230: my $peerport;
231: my $peerip;
232: if($AdrFamily == AF_INET) {
233: ($peerport, $peerip) = sockaddr_in($peer);
234: my $peername = gethostbyaddr($peerip, $AdrFamily);
235: return $peername;
236: } elsif ($AdrFamily == AF_UNIX) {
237: my $peerfile;
238: ($peerfile) = sockaddr_un($peer);
239: return $peerfile;
240: }
241: }
242: =pod
243:
244: =head2 Debug
245:
246: Invoked to issue a debug message.
247:
248: =cut
249:
250: sub Debug {
251:
252: my ($level, $message) = @_;
253:
254: if ($level <= $DebugLevel) {
255: Log("INFO", "-Debug- $message host = $RemoteHost");
256: }
257: }
258:
259: sub SocketDump {
260:
261: my ($level, $socket) = @_;
262:
263: if($level <= $DebugLevel) {
264: $socket->Dump(-1); # Ensure it will get dumped.
265: }
266: }
267:
268: =pod
269:
270: =head2 ShowStatus
271:
272: Place some text as our pid status.
273: and as what we return in a SIGUSR1
274:
275: =cut
276:
277: sub ShowStatus {
278: my $state = shift;
279: my $now = time;
280: my $local = localtime($now);
281: $Status = $local.": ".$state;
282: $0='lonc: '.$state.' '.$local;
283: }
284:
285: =pod
286:
287: =head2 SocketTimeout
288:
289: Called when an action on the socket times out. The socket is
290: destroyed and any active transaction is failed.
291:
292:
293: =cut
294:
295: sub SocketTimeout {
296: my $Socket = shift;
297: Log("WARNING", "A socket timeout was detected");
298: Debug(5, " SocketTimeout called: ");
299: $Socket->Dump(0);
300: if(exists($ActiveTransactions{$Socket})) {
301: FailTransaction($ActiveTransactions{$Socket});
302: }
303: KillSocket($Socket); # A transaction timeout also counts as
304: # a connection failure:
305: $ConnectionRetriesLeft--;
306: if($ConnectionRetriesLeft <= 0) {
307: Log("CRITICAL", "Host marked DEAD: ".GetServerHost());
308: $LondConnecting = 0;
309: }
310:
311: }
312: #
313: # This function should be called by the child in all cases where it must
314: # exit. If the child process is running with the DieWhenIdle turned on
315: # it must create a lock file for the AF_UNIX socket in order to prevent
316: # connection requests from lonnet in the time between process exit
317: # and the parent picking up the listen again.
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: if($DieWhenIdle) {
329: #
330: # Create a lock file since there will be a time window
331: # between our exit and the parent's picking up the listen
332: # during which no listens will be done on the
333: # lonnet client socket.
334: #
335: my $lock_file = &GetLoncSocketPath().".lock";
336: open(LOCK,">$lock_file");
337: print LOCK "Contents not important";
338: close(LOCK);
339: if ($hosts_tab) {
340: unlink(&GetLoncSocketPath());
341: }
342: exit(0);
343: }
344: # Now figure out how we exit:
345:
346: if($message) {
347: die $message;
348: } else {
349: exit($exit_code);
350: }
351: }
352: #----------------------------- Timer management ------------------------
353:
354: =pod
355:
356: =head2 Tick
357:
358: Invoked each timer tick.
359:
360: =cut
361:
362:
363: sub Tick {
364: my ($Event) = @_;
365: my $clock_watcher = $Event->w;
366:
367: my $client;
368: UpdateStatus();
369:
370: # Is it time to prune connection count:
371:
372:
373: if($IdleConnections->Count() &&
374: ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
375: $IdleSeconds++;
376: if($IdleSeconds > $IdleTimeout) { # Prune a connection...
377: my $Socket = $IdleConnections->pop();
378: KillSocket($Socket);
379: $IdleSeconds = 0; # Otherwise all connections get trimmed to fast.
380: UpdateStatus();
381: if(($ConnectionCount == 0) && $DieWhenIdle) {
382: &child_exit(0);
383:
384: }
385: }
386: } else {
387: $IdleSeconds = 0; # Reset idle count if not idle.
388: }
389: #
390: # For each inflight transaction, tick down its timeout counter.
391: #
392:
393: foreach my $item (keys %ActiveConnections) {
394: my $State = $ActiveConnections{$item}->data->GetState();
395: if ($State ne 'Idle') {
396: Debug(5,"Ticking Socket $State $item");
397: $ActiveConnections{$item}->data->Tick();
398: }
399: }
400: # Do we have work in the queue, but no connections to service them?
401: # If so, try to make some new connections to get things going again.
402: #
403: # Note this code is dead now...
404: #
405: my $Requests = $WorkQueue->Count();
406: if (($ConnectionCount == 0) && ($Requests > 0) && (!$LondConnecting)) {
407: if ($ConnectionRetriesLeft > 0) {
408: Debug(5,"Work but no connections, Make a new one");
409: my $success;
410: $success = &MakeLondConnection;
411: if($success == 0) { # All connections failed:
412: Debug(5,"Work in queue failed to make any connectiouns\n");
413: EmptyQueue(); # Fail pending transactions with con_lost.
414: CloseAllLondConnections(); # Should all be closed but....
415: }
416: } else {
417: $LondConnecting = 0;
418: ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
419: Debug(5,"Work in queue, but gave up on connections..flushing\n");
420: EmptyQueue(); # Connections can't be established.
421: CloseAllLondConnections(); # Should all already be closed but...
422: }
423:
424: }
425: if ($ConnectionCount == 0) {
426: $KeyMode = "";
427: $clock_watcher->cancel();
428: }
429: &UpdateStatus();
430: }
431:
432: =pod
433:
434: =head2 SetupTimer
435:
436: Sets up a 1 per sec recurring timer event. The event handler is used to:
437:
438: =item
439:
440: Trigger timeouts on communications along active sockets.
441:
442: =item
443:
444: Trigger disconnections of idle sockets.
445:
446: =cut
447:
448: sub SetupTimer {
449: Debug(6, "SetupTimer");
450: Event->timer(interval => 1, cb => \&Tick );
451: }
452:
453: =pod
454:
455: =head2 ServerToIdle
456:
457: This function is called when a connection to the server is
458: ready for more work.
459:
460: If there is work in the Work queue the top element is dequeued
461: and the connection will start to work on it. If the work queue is
462: empty, the connection is pushed on the idle connection stack where
463: it will either get another work unit, or alternatively, if it sits there
464: long enough, it will be shut down and released.
465:
466: =cut
467:
468: sub ServerToIdle {
469: my $Socket = shift; # Get the socket.
470: $KeyMode = $Socket->{AuthenticationMode};
471: delete($ActiveTransactions{$Socket}); # Server has no transaction
472:
473: &Debug(5, "Server to idle");
474:
475: # If there's work to do, start the transaction:
476:
477: my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
478: if ($reqdata ne undef) {
479: Debug(5, "Queue gave request data: ".$reqdata->getRequest());
480: &StartRequest($Socket, $reqdata);
481:
482: } else {
483:
484: # There's no work waiting, so push the server to idle list.
485: &Debug(5, "No new work requests, server connection going idle");
486: $IdleConnections->push($Socket);
487: }
488: }
489:
490: =pod
491:
492: =head2 ClientWritable
493:
494: Event callback for when a client socket is writable.
495:
496: This callback is established when a transaction reponse is
497: avaiable from lond. The response is forwarded to the unix socket
498: as it becomes writable in this sub.
499:
500: Parameters:
501:
502: =item Event
503:
504: The event that has been triggered. Event->w->data is
505: the data and Event->w->fd is the socket to write.
506:
507: =cut
508:
509: sub ClientWritable {
510: my $Event = shift;
511: my $Watcher = $Event->w;
512: my $Data = $Watcher->data;
513: my $Socket = $Watcher->fd;
514:
515: # Try to send the data:
516:
517: &Debug(6, "ClientWritable writing".$Data);
518: &Debug(9, "Socket is: ".$Socket);
519:
520: if($Socket->connected) {
521: my $result = $Socket->send($Data, 0);
522:
523: # $result undefined: the write failed.
524: # otherwise $result is the number of bytes written.
525: # Remove that preceding string from the data.
526: # If the resulting data is empty, destroy the watcher
527: # and set up a read event handler to accept the next
528: # request.
529:
530: &Debug(9,"Send result is ".$result." Defined: ".defined($result));
531: if($result ne undef) {
532: &Debug(9, "send result was defined");
533: if($result == length($Data)) { # Entire string sent.
534: &Debug(9, "ClientWritable data all written");
535: $Watcher->cancel();
536: #
537: # Set up to read next request from socket:
538:
539: my $descr = sprintf("Connection to lonc client %d",
540: $ActiveClients{$Socket});
541: Event->io(cb => \&ClientRequest,
542: poll => 'r',
543: desc => $descr,
544: data => "",
545: fd => $Socket);
546:
547: } else { # Partial string sent.
548: $Watcher->data(substr($Data, $result));
549: if($result == 0) { # client hung up on us!!
550: # Log("INFO", "lonc pipe client hung up on us!");
551: $Watcher->cancel;
552: $Socket->shutdown(2);
553: $Socket->close();
554: }
555: }
556:
557: } else { # Error of some sort...
558:
559: # Some errnos are possible:
560: my $errno = $!;
561: if($errno == POSIX::EWOULDBLOCK ||
562: $errno == POSIX::EAGAIN ||
563: $errno == POSIX::EINTR) {
564: # No action taken?
565: } else { # Unanticipated errno.
566: &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
567: $Watcher->cancel; # Stop the watcher.
568: $Socket->shutdown(2); # Kill connection
569: $Socket->close(); # Close the socket.
570: }
571:
572: }
573: } else {
574: $Watcher->cancel(); # A delayed request...just cancel.
575: }
576: }
577:
578: =pod
579:
580: =head2 CompleteTransaction
581:
582: Called when the reply data has been received for a lond
583: transaction. The reply data must now be sent to the
584: ultimate client on the other end of the Unix socket. This is
585: done by setting up a writable event for the socket with the
586: data the reply data.
587:
588: Parameters:
589:
590: =item Socket
591:
592: Socket on which the lond transaction occured. This is a
593: LondConnection. The data received is in the TransactionReply member.
594:
595: =item Transaction
596:
597: The transaction that is being completed.
598:
599: =cut
600:
601: sub CompleteTransaction {
602: &Debug(5,"Complete transaction");
603:
604: my ($Socket, $Transaction) = @_;
605:
606: if (!$Transaction->isDeferred()) { # Normal transaction
607: my $data = $Socket->GetReply(); # Data to send.
608: if($LogTransactions) {
609: Log("SUCCESS", "Reply from lond: '$data'");
610: }
611: StartClientReply($Transaction, $data);
612: } else { # Delete deferred transaction file.
613: Log("SUCCESS", "A delayed transaction was completed");
614: LogPerm("S:$Transaction->getClient() :".$Transaction->getRequest());
615: unlink $Transaction->getFile();
616: }
617: }
618:
619: =pod
620:
621: =head1 StartClientReply
622:
623: Initiates a reply to a client where the reply data is a parameter.
624:
625: =head2 parameters:
626:
627: =item Transaction
628:
629: The transaction for which we are responding to the client.
630:
631: =item data
632:
633: The data to send to apached client.
634:
635: =cut
636:
637: sub StartClientReply {
638:
639: my ($Transaction, $data) = @_;
640:
641: my $Client = $Transaction->getClient();
642:
643: &Debug(8," Reply was: ".$data);
644: my $Serial = $ActiveClients{$Client};
645: my $desc = sprintf("Connection to lonc client %d",
646: $Serial);
647: Event->io(fd => $Client,
648: poll => "w",
649: desc => $desc,
650: cb => \&ClientWritable,
651: data => $data);
652: }
653:
654: =pod
655:
656: =head2 FailTransaction
657:
658: Finishes a transaction with failure because the associated lond socket
659: disconnected. There are two possibilities:
660: - The transaction is deferred: in which case we just quietly
661: delete the transaction since there is no client connection.
662: - The transaction is 'live' in which case we initiate the sending
663: of "con_lost" to the client.
664:
665: Deleting the transaction means killing it from the %ActiveTransactions hash.
666:
667: Parameters:
668:
669: =item client
670:
671: The LondTransaction we are failing.
672:
673:
674: =cut
675:
676: sub FailTransaction {
677: my $transaction = shift;
678:
679: # If the socket is dead, that's already logged.
680:
681: if ($ConnectionRetriesLeft > 0) {
682: Log("WARNING", "Failing transaction "
683: .$transaction->getLoggableRequest());
684: }
685: Debug(1, "Failing transaction: ".$transaction->getLoggableRequest());
686: if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
687: my $client = $transaction->getClient();
688: Debug(1," Replying con_lost to ".$transaction->getRequest());
689: StartClientReply($transaction, "con_lost\n");
690: }
691:
692: }
693:
694: =pod
695:
696: =head1 EmptyQueue
697:
698: Fails all items in the work queue with con_lost.
699: Note that each item in the work queue is a transaction.
700:
701: =cut
702:
703: sub EmptyQueue {
704: $ConnectionRetriesLeft--; # Counts as connection failure too.
705: while($WorkQueue->Count()) {
706: my $request = $WorkQueue->dequeue(); # This is a transaction
707: FailTransaction($request);
708: }
709: }
710:
711: =pod
712:
713: =head2 CloseAllLondConnections
714:
715: Close all connections open on lond prior to exit e.g.
716:
717: =cut
718:
719: sub CloseAllLondConnections {
720: foreach my $Socket (keys %ActiveConnections) {
721: if(exists($ActiveTransactions{$Socket})) {
722: FailTransaction($ActiveTransactions{$Socket});
723: }
724: KillSocket($Socket);
725: }
726: }
727:
728: =pod
729:
730: =head2 KillSocket
731:
732: Destroys a socket. This function can be called either when a socket
733: has died of 'natural' causes or because a socket needs to be pruned due to
734: idleness. If the socket has died naturally, if there are no longer any
735: live connections a new connection is created (in case there are transactions
736: in the queue). If the socket has been pruned, it is never re-created.
737:
738: Parameters:
739:
740: =item Socket
741:
742: The socket to kill off.
743:
744: =item Restart
745:
746: nonzero if we are allowed to create a new connection.
747:
748: =cut
749:
750: sub KillSocket {
751: my $Socket = shift;
752:
753: Log("WARNING", "Shutting down a socket");
754: $Socket->Shutdown();
755:
756: # If the socket came from the active connection set,
757: # delete its transaction... note that FailTransaction should
758: # already have been called!!!
759: # otherwise it came from the idle set.
760: #
761:
762: if(exists($ActiveTransactions{$Socket})) {
763: delete ($ActiveTransactions{$Socket});
764: }
765: if(exists($ActiveConnections{$Socket})) {
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: }
778:
779: =pod
780:
781: =head2 LondReadable
782:
783: This function is called whenever a lond connection
784: is readable. The action is state dependent:
785:
786: =head3 State=Initialized
787:
788: We''re waiting for the challenge, this is a no-op until the
789: state changes.
790:
791: =head3 State=Challenged
792:
793: The challenge has arrived we need to transition to Writable.
794: The connection must echo the challenge back.
795:
796: =head3 State=ChallengeReplied
797:
798: The challenge has been replied to. The we are receiveing the
799: 'ok' from the partner.
800:
801: =head3 State=ReadingVersionString
802:
803: We have requested the lond version and are reading the
804: version back. Upon completion, we'll store the version away
805: for future use(?).
806:
807: =head3 State=HostSet
808:
809: We have selected the domain name of our peer (multhomed hosts)
810: and are getting the reply (presumably ok) back.
811:
812: =head3 State=RequestingKey
813:
814: The ok has been received and we need to send the request for
815: an encryption key. Transition to writable for that.
816:
817: =head3 State=ReceivingKey
818:
819: The the key has been requested, now we are reading the new key.
820:
821: =head3 State=Idle
822:
823: The encryption key has been negotiated or we have finished
824: reading data from the a transaction. If the callback data has
825: a client as well as the socket iformation, then we are
826: doing a transaction and the data received is relayed to the client
827: before the socket is put on the idle list.
828:
829: =head3 State=SendingRequest
830:
831: I do not think this state can be received here, but if it is,
832: the appropriate thing to do is to transition to writable, and send
833: the request.
834:
835: =head3 State=ReceivingReply
836:
837: We finished sending the request to the server and now transition
838: to readable to receive the reply.
839:
840: The parameter to this function are:
841:
842: The event. Implicit in this is the watcher and its data. The data
843: contains at least the lond connection object and, if a
844: transaction is in progress, the socket attached to the local client.
845:
846: =cut
847:
848: sub LondReadable {
849:
850: my $Event = shift;
851: my $Watcher = $Event->w;
852: my $Socket = $Watcher->data;
853: my $client = undef;
854:
855: &Debug(6,"LondReadable called state = ".$Socket->GetState());
856:
857:
858: my $State = $Socket->GetState(); # All action depends on the state.
859:
860: SocketDump(6, $Socket);
861: my $status = $Socket->Readable();
862:
863: &Debug(2, "Socket->Readable returned: $status");
864:
865: if($status != 0) {
866: # bad return from socket read. Currently this means that
867: # The socket has become disconnected. We fail the transaction.
868:
869: Log("WARNING",
870: "Lond connection lost.");
871: if(exists($ActiveTransactions{$Socket})) {
872: FailTransaction($ActiveTransactions{$Socket});
873: } else {
874: # Socket is connecting and failed... need to mark
875: # no longer connecting.
876:
877: $LondConnecting = 0;
878: }
879: $Watcher->cancel();
880: KillSocket($Socket);
881: $ConnectionRetriesLeft--; # Counts as connection failure
882: return;
883: }
884: SocketDump(6,$Socket);
885:
886: $State = $Socket->GetState(); # Update in case of transition.
887: &Debug(6, "After read, state is ".$State);
888:
889: if($State eq "Initialized") {
890:
891:
892: } elsif ($State eq "ChallengeReceived") {
893: # The challenge must be echoed back; The state machine
894: # in the connection takes care of setting that up. Just
895: # need to transition to writable:
896:
897: $Watcher->cb(\&LondWritable);
898: $Watcher->poll("w");
899:
900: } elsif ($State eq "ChallengeReplied") {
901:
902: } elsif ($State eq "RequestingVersion") {
903: # Need to ask for the version... that is writiability:
904:
905: $Watcher->cb(\&LondWritable);
906: $Watcher->poll("w");
907:
908: } elsif ($State eq "ReadingVersionString") {
909: # Read the rest of the version string...
910: } elsif ($State eq "SetHost") {
911: # Need to request the actual domain get set...
912:
913: $Watcher->cb(\&LondWritable);
914: $Watcher->poll("w");
915: } elsif ($State eq "HostSet") {
916: # Reading the 'ok' from the peer.
917:
918: } elsif ($State eq "RequestingKey") {
919: # The ok was received. Now we need to request the key
920: # That requires us to be writable:
921:
922: $Watcher->cb(\&LondWritable);
923: $Watcher->poll("w");
924:
925: } elsif ($State eq "ReceivingKey") {
926:
927: } elsif ($State eq "Idle") {
928:
929: # This is as good a spot as any to get the peer version
930: # string:
931:
932: if($LondVersion eq "unknown") {
933: $LondVersion = $Socket->PeerVersion();
934: Log("INFO", "Connected to lond version: $LondVersion");
935: }
936: # If necessary, complete a transaction and then go into the
937: # idle queue.
938: # Note that a trasition to idle indicates a live lond
939: # on the other end so reset the connection retries.
940: #
941: $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
942: $Watcher->cancel();
943: if(exists($ActiveTransactions{$Socket})) {
944: Debug(5,"Completing transaction!!");
945: CompleteTransaction($Socket,
946: $ActiveTransactions{$Socket});
947: } else {
948: Log("SUCCESS", "Connection ".$ConnectionCount." to "
949: .$RemoteHost." now ready for action");
950: }
951: ServerToIdle($Socket); # Next work unit or idle.
952:
953: #
954: $LondConnecting = 0; # Best spot I can think of for this.
955: #
956:
957: } elsif ($State eq "SendingRequest") {
958: # We need to be writable for this and probably don't belong
959: # here inthe first place.
960:
961: Debug(6, "SendingRequest state encountered in readable");
962: $Watcher->poll("w");
963: $Watcher->cb(\&LondWritable);
964:
965: } elsif ($State eq "ReceivingReply") {
966:
967:
968: } else {
969: # Invalid state.
970: Debug(4, "Invalid state in LondReadable");
971: }
972: }
973:
974: =pod
975:
976: =head2 LondWritable
977:
978: This function is called whenever a lond connection
979: becomes writable while there is a writeable monitoring
980: event. The action taken is very state dependent:
981:
982: =head3 State = Connected
983:
984: The connection is in the process of sending the 'init' hailing to the
985: lond on the remote end. The connection object''s Writable member is
986: called. On error, ConnectionError is called to destroy the connection
987: and remove it from the ActiveConnections hash
988:
989: =head3 Initialized
990:
991: 'init' has been sent, writability monitoring is removed and
992: readability monitoring is started with LondReadable as the callback.
993:
994: =head3 ChallengeReceived
995:
996: The connection has received the who are you challenge from the remote
997: system, and is in the process of sending the challenge
998: response. Writable is called.
999:
1000: =head3 ChallengeReplied
1001:
1002: The connection has replied to the initial challenge The we switch to
1003: monitoring readability looking for the server to reply with 'ok'.
1004:
1005: =head3 RequestingKey
1006:
1007: The connection is in the process of requesting its encryption key.
1008: Writable is called.
1009:
1010: =head3 ReceivingKey
1011:
1012: The connection has sent the request for a key. Switch to readability
1013: monitoring to accept the key
1014:
1015: =head3 SendingRequest
1016:
1017: The connection is in the process of sending a request to the server.
1018: This request is part of a client transaction. All the states until
1019: now represent the client setup protocol. Writable is called.
1020:
1021: =head3 ReceivingReply
1022:
1023: The connection has sent a request. Now it must receive a reply.
1024: Readability monitoring is requested.
1025:
1026: This function is an event handler and therefore receives as
1027: a parameter the event that has fired. The data for the watcher
1028: of this event is a reference to a list of one or two elements,
1029: depending on state. The first (and possibly only) element is the
1030: socket. The second (present only if a request is in progress)
1031: is the socket on which to return a reply to the caller.
1032:
1033: =cut
1034:
1035: sub LondWritable {
1036: my $Event = shift;
1037: my $Watcher = $Event->w;
1038: my $Socket = $Watcher->data;
1039: my $State = $Socket->GetState();
1040:
1041: Debug(6,"LondWritable State = ".$State."\n");
1042:
1043:
1044: # Figure out what to do depending on the state of the socket:
1045:
1046:
1047:
1048:
1049: SocketDump(6,$Socket);
1050:
1051: # If the socket is writable, we must always write.
1052: # Only by writing will we undergo state transitions.
1053: # Old logic wrote in state specific code below, however
1054: # That forces us at least through another invocation of
1055: # this function after writability is possible again.
1056: # This logic also factors out common code for handling
1057: # write failures... in all cases, write failures
1058: # Kill the socket.
1059: # This logic makes the branches of the >big< if below
1060: # so that the writing states are actually NO-OPs.
1061:
1062: if ($Socket->Writable() != 0) {
1063: # The write resulted in an error.
1064: # We'll treat this as if the socket got disconnected:
1065: Log("WARNING", "Connection to ".$RemoteHost.
1066: " has been disconnected");
1067: if(exists($ActiveTransactions{$Socket})) {
1068: FailTransaction($ActiveTransactions{$Socket});
1069: } else {
1070: # In the process of conneting, so need to turn that off.
1071:
1072: $LondConnecting = 0;
1073: }
1074: $Watcher->cancel();
1075: KillSocket($Socket);
1076: return;
1077: }
1078:
1079:
1080:
1081: if ($State eq "Connected") {
1082:
1083: # "init" is being sent...
1084:
1085: } elsif ($State eq "Initialized") {
1086:
1087: # Now that init was sent, we switch
1088: # to watching for readability:
1089:
1090: $Watcher->cb(\&LondReadable);
1091: $Watcher->poll("r");
1092:
1093: } elsif ($State eq "ChallengeReceived") {
1094: # We received the challenge, now we
1095: # are echoing it back. This is a no-op,
1096: # we're waiting for the state to change
1097:
1098: } elsif ($State eq "ChallengeReplied") {
1099: # The echo was sent back, so we switch
1100: # to watching readability.
1101:
1102: $Watcher->cb(\&LondReadable);
1103: $Watcher->poll("r");
1104: } elsif ($State eq "RequestingVersion") {
1105: # Sending the peer a version request...
1106:
1107: } elsif ($State eq "ReadingVersionString") {
1108: # Transition to read since we have sent the
1109: # version command and now just need to read the
1110: # version string from the peer:
1111:
1112: $Watcher->cb(\&LondReadable);
1113: $Watcher->poll("r");
1114:
1115: } elsif ($State eq "SetHost") {
1116: # Setting the remote domain...
1117:
1118: } elsif ($State eq "HostSet") {
1119: # Back to readable to get the ok.
1120:
1121: $Watcher->cb(\&LondReadable);
1122: $Watcher->poll("r");
1123:
1124:
1125: } elsif ($State eq "RequestingKey") {
1126: # At this time we're requesting the key.
1127: # again, this is essentially a no-op.
1128:
1129: } elsif ($State eq "ReceivingKey") {
1130: # Now we need to wait for the key
1131: # to come back from the peer:
1132:
1133: $Watcher->cb(\&LondReadable);
1134: $Watcher->poll("r");
1135:
1136: } elsif ($State eq "SendingRequest") {
1137:
1138: # At this time we are sending a request to the
1139: # peer... write the next chunk:
1140:
1141:
1142: } elsif ($State eq "ReceivingReply") {
1143: # The send has completed. Wait for the
1144: # data to come in for a reply.
1145: Debug(8,"Writable sent request/receiving reply");
1146: $Watcher->cb(\&LondReadable);
1147: $Watcher->poll("r");
1148:
1149: } else {
1150: # Control only passes here on an error:
1151: # the socket state does not match any
1152: # of the known states... so an error
1153: # must be logged.
1154:
1155: &Debug(4, "Invalid socket state ".$State."\n");
1156: }
1157:
1158: }
1159: =pod
1160:
1161: =cut
1162:
1163: sub QueueDelayed {
1164: Debug(3,"QueueDelayed called");
1165:
1166: my $path = "$perlvar{'lonSockDir'}/delayed";
1167:
1168: Debug(4, "Delayed path: ".$path);
1169: opendir(DIRHANDLE, $path);
1170:
1171: my @all_host_ids;
1172: my $host_iterator = &LondConnection::GetHostIterator();
1173: while (!$host_iterator->end()) {
1174: my ($host_id,$host_name) = @{$host_iterator->get()}[0,3];
1175: if ($host_name eq $RemoteHost) {
1176: push(@all_host_ids, $host_id);
1177: }
1178: $host_iterator->next();
1179: }
1180: my $host_id_re = '(?:'.join('|',@all_host_ids).')';
1181: my @alldelayed = grep(/\.$host_id_re$/, readdir(DIRHANDLE));
1182: closedir(DIRHANDLE);
1183: foreach my $dfname (sort(@alldelayed)) {
1184: my $reqfile = "$path/$dfname";
1185: my ($host_id) = ($dfname =~ /\.([^.]*)$/);
1186: Debug(4, "queueing ".$reqfile." for $host_id");
1187: my $Handle = IO::File->new($reqfile);
1188: my $cmd = <$Handle>;
1189: chomp $cmd; # There may or may not be a newline...
1190: $cmd = $cmd."\n"; # now for sure there's exactly one newline.
1191: my $Transaction = LondTransaction->new("sethost:$host_id:$cmd");
1192: $Transaction->SetDeferred($reqfile);
1193: QueueTransaction($Transaction);
1194: }
1195:
1196: }
1197:
1198: =pod
1199:
1200: =head2 MakeLondConnection
1201:
1202: Create a new lond connection object, and start it towards its initial
1203: idleness. Once idle, it becomes elligible to receive transactions
1204: from the work queue. If the work queue is not empty when the
1205: connection is completed and becomes idle, it will dequeue an entry and
1206: start off on it.
1207:
1208: =cut
1209:
1210: sub MakeLondConnection {
1211: Debug(4,"MakeLondConnection to ".GetServerHost()." on port "
1212: .GetServerPort());
1213:
1214: my $Connection = LondConnection->new(&GetServerHost(),
1215: &GetServerPort());
1216:
1217: if($Connection eq undef) { # Needs to be more robust later.
1218: Log("CRITICAL","Failed to make a connection with lond.");
1219: $ConnectionRetriesLeft--;
1220: return 0; # Failure.
1221: } else {
1222:
1223: # The connection needs to have writability
1224: # monitored in order to send the init sequence
1225: # that starts the whole authentication/key
1226: # exchange underway.
1227: #
1228: my $Socket = $Connection->GetSocket();
1229: if($Socket eq undef) {
1230: &child_exit(-1, "did not get a socket from the connection");
1231: } else {
1232: &Debug(9,"MakeLondConnection got socket: ".$Socket);
1233: }
1234:
1235: $Connection->SetTimeoutCallback(\&SocketTimeout);
1236:
1237: my $event = Event->io(fd => $Socket,
1238: poll => 'w',
1239: cb => \&LondWritable,
1240: data => $Connection,
1241: desc => 'Connection to lond server');
1242: $ActiveConnections{$Connection} = $event;
1243: if ($ConnectionCount == 0) {
1244: &SetupTimer; # Need to handle timeouts with connections...
1245: }
1246: $ConnectionCount++;
1247: Debug(4, "Connection count = ".$ConnectionCount);
1248: if($ConnectionCount == 1) { # First Connection:
1249: QueueDelayed;
1250: }
1251: Log("SUCESS", "Created connection ".$ConnectionCount
1252: ." to host ".GetServerHost());
1253: $LondConnecting = 1; # Connection in progress.
1254: return 1; # Return success.
1255: }
1256:
1257: }
1258:
1259: =pod
1260:
1261: =head2 StartRequest
1262:
1263: Starts a lond request going on a specified lond connection.
1264: parameters are:
1265:
1266: =item $Lond
1267:
1268: Connection to the lond that will send the transaction and receive the
1269: reply.
1270:
1271: =item $Client
1272:
1273: Connection to the client that is making this request We got the
1274: request from this socket, and when the request has been relayed to
1275: lond and we get a reply back from lond it will get sent to this
1276: socket.
1277:
1278: =item $Request
1279:
1280: The text of the request to send.
1281:
1282: =cut
1283:
1284: sub StartRequest {
1285:
1286: my ($Lond, $Request) = @_;
1287:
1288: Debug(6, "StartRequest: ".$Request->getRequest());
1289:
1290: my $Socket = $Lond->GetSocket();
1291:
1292: $Request->Activate($Lond);
1293: $ActiveTransactions{$Lond} = $Request;
1294:
1295: $Lond->InitiateTransaction($Request->getRequest());
1296: my $event = Event->io(fd => $Socket,
1297: poll => "w",
1298: cb => \&LondWritable,
1299: data => $Lond,
1300: desc => "lond transaction connection");
1301: $ActiveConnections{$Lond} = $event;
1302: Debug(8," Start Request made watcher data with ".$event->data."\n");
1303: }
1304:
1305: =pod
1306:
1307: =head2 QueueTransaction
1308:
1309: If there is an idle lond connection, it is put to work doing this
1310: transaction. Otherwise, the transaction is placed in the work queue.
1311: If placed in the work queue and the maximum number of connections has
1312: not yet been created, a new connection will be started. Our goal is
1313: to eventually have a sufficient number of connections that the work
1314: queue will typically be empty. parameters are:
1315:
1316: =item Socket
1317:
1318: open on the lonc client.
1319:
1320: =item Request
1321:
1322: data to send to the lond.
1323:
1324: =cut
1325:
1326: sub QueueTransaction {
1327:
1328: my $requestData = shift; # This is a LondTransaction.
1329: my $cmd = $requestData->getRequest();
1330:
1331: Debug(6,"QueueTransaction: ".$cmd);
1332:
1333: my $LondSocket = $IdleConnections->pop();
1334: if(!defined $LondSocket) { # Need to queue request.
1335: Debug(5,"Must queue...");
1336: $WorkQueue->enqueue($requestData);
1337: Debug(5, "Queue Transaction startnew $ConnectionCount $LondConnecting");
1338: if(($ConnectionCount < $MaxConnectionCount) && (! $LondConnecting)) {
1339:
1340: if($ConnectionRetriesLeft > 0) {
1341: Debug(5,"Starting additional lond connection");
1342: if(&MakeLondConnection() == 0) {
1343: EmptyQueue(); # Fail transactions, can't make connection.
1344: CloseAllLondConnections; # Should all be closed but...
1345: }
1346: } else {
1347: ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
1348: $LondConnecting = 0;
1349: EmptyQueue(); # It's worse than that ... he's dead Jim.
1350: CloseAllLondConnections; # Should all be closed but..
1351: }
1352: }
1353: } else { # Can start the request:
1354: Debug(8,"Can start...");
1355: StartRequest($LondSocket, $requestData);
1356: }
1357: }
1358:
1359: #-------------------------- Lonc UNIX socket handling ---------------------
1360:
1361: =pod
1362:
1363: =head2 ClientRequest
1364: Callback that is called when data can be read from the UNIX domain
1365: socket connecting us with an apache server process.
1366:
1367: =cut
1368:
1369: sub ClientRequest {
1370: Debug(6, "ClientRequest");
1371: my $event = shift;
1372: my $watcher = $event->w;
1373: my $socket = $watcher->fd;
1374: my $data = $watcher->data;
1375: my $thisread;
1376:
1377: Debug(9, " Watcher named: ".$watcher->desc);
1378:
1379: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1380: Debug(8, "rcv: data length = ".length($thisread)
1381: ." read =".$thisread);
1382: unless (defined $rv && length($thisread)) {
1383: # Likely eof on socket.
1384: Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
1385: close($socket);
1386: $watcher->cancel();
1387: delete($ActiveClients{$socket});
1388: return;
1389: }
1390: Debug(8,"Data: ".$data." this read: ".$thisread);
1391: $data = $data.$thisread; # Append new data.
1392: $watcher->data($data);
1393: if($data =~ /\n$/) { # Request entirely read.
1394: if($data eq "close_connection_exit\n") {
1395: Log("CRITICAL",
1396: "Request Close Connection ... exiting");
1397: CloseAllLondConnections();
1398: exit;
1399: }
1400: Debug(8, "Complete transaction received: ".$data);
1401: if($LogTransactions) {
1402: Log("SUCCESS", "Transaction: '$data'"); # Transaction has \n.
1403: }
1404: my $Transaction = LondTransaction->new($data);
1405: $Transaction->SetClient($socket);
1406: QueueTransaction($Transaction);
1407: $watcher->cancel(); # Done looking for input data.
1408: }
1409:
1410: }
1411:
1412: #
1413: # Accept a connection request for a client (lonc child) and
1414: # start up an event watcher to keep an eye on input from that
1415: # Event. This can be called both from NewClient and from
1416: # ChildProcess if we are started in DieWhenIdle mode.
1417: # Parameters:
1418: # $socket - The listener socket.
1419: # Returns:
1420: # NONE
1421: # Side Effects:
1422: # An event is made to watch the accepted connection.
1423: # Active clients hash is updated to reflect the new connection.
1424: # The client connection count is incremented.
1425: #
1426: sub accept_client {
1427: my ($socket) = @_;
1428:
1429: Debug(8, "Entering accept for lonc UNIX socket\n");
1430: my $connection = $socket->accept(); # Accept the client connection.
1431: Debug(8,"Connection request accepted from "
1432: .GetPeername($connection, AF_UNIX));
1433:
1434:
1435: my $description = sprintf("Connection to lonc client %d",
1436: $ClientConnection);
1437: Debug(9, "Creating event named: ".$description);
1438: Event->io(cb => \&ClientRequest,
1439: poll => 'r',
1440: desc => $description,
1441: data => "",
1442: fd => $connection);
1443: $ActiveClients{$connection} = $ClientConnection;
1444: $ClientConnection++;
1445: }
1446:
1447: =pod
1448:
1449: =head2 NewClient
1450:
1451: Callback that is called when a connection is received on the unix
1452: socket for a new client of lonc. The callback is parameterized by the
1453: event.. which is a-priori assumed to be an io event, and therefore has
1454: an fd member that is the Listener socket. We Accept the connection
1455: and register a new event on the readability of that socket:
1456:
1457: =cut
1458:
1459: sub NewClient {
1460: Debug(6, "NewClient");
1461: my $event = shift; # Get the event parameters.
1462: my $watcher = $event->w;
1463: my $socket = $watcher->fd; # Get the event' socket.
1464:
1465: &accept_client($socket);
1466: }
1467:
1468: =pod
1469:
1470: =head2 GetLoncSocketPath
1471:
1472: Returns the name of the UNIX socket on which to listen for client
1473: connections.
1474:
1475: =head2 Parameters:
1476:
1477: host (optional) - Name of the host socket to return.. defaults to
1478: the return from GetServerHost().
1479:
1480: =cut
1481:
1482: sub GetLoncSocketPath {
1483:
1484: my $host = GetServerHost(); # Default host.
1485: if (@_) {
1486: ($host) = @_; # Override if supplied.
1487: }
1488: return $UnixSocketDir."/".$host;
1489: }
1490:
1491: =pod
1492:
1493: =head2 GetServerHost
1494:
1495: Returns the host whose lond we talk with.
1496:
1497: =cut
1498:
1499: sub GetServerHost {
1500: return $RemoteHost; # Setup by the fork.
1501: }
1502:
1503: =pod
1504:
1505: =head2 GetServerPort
1506:
1507: Returns the lond port number.
1508:
1509: =cut
1510:
1511: sub GetServerPort {
1512: return $perlvar{londPort};
1513: }
1514:
1515: =pod
1516:
1517: =head2 SetupLoncListener
1518:
1519: Setup a lonc listener event. The event is called when the socket
1520: becomes readable.. that corresponds to the receipt of a new
1521: connection. The event handler established will accept the connection
1522: (creating a communcations channel), that int turn will establish
1523: another event handler to subess requests.
1524:
1525: =head2 Parameters:
1526:
1527: host (optional) Name of the host to set up a unix socket to.
1528:
1529: =cut
1530:
1531: sub SetupLoncListener {
1532: my ($host,$SocketName) = @_;
1533: if (!$host) { $host = &GetServerHost(); }
1534: if (!$SocketName) { $SocketName = &GetLoncSocketPath($host); }
1535:
1536:
1537: unlink($SocketName);
1538:
1539: my $socket;
1540: unless ($socket =IO::Socket::UNIX->new(Local => $SocketName,
1541: Listen => 250,
1542: Type => SOCK_STREAM)) {
1543: if($I_am_child) {
1544: &child_exit(-1, "Failed to create a lonc listener socket");
1545: } else {
1546: die "Failed to create a lonc listner socket";
1547: }
1548: }
1549: return $socket;
1550: }
1551:
1552: #
1553: # Toggle transaction logging.
1554: # Implicit inputs:
1555: # LogTransactions
1556: # Implicit Outputs:
1557: # LogTransactions
1558: sub ToggleTransactionLogging {
1559: print STDERR "Toggle transaction logging...\n";
1560: if(!$LogTransactions) {
1561: $LogTransactions = 1;
1562: } else {
1563: $LogTransactions = 0;
1564: }
1565:
1566:
1567: Log("SUCCESS", "Toggled transaction logging: $LogTransactions \n");
1568: }
1569:
1570: =pod
1571:
1572: =head2 ChildStatus
1573:
1574: Child USR1 signal handler to report the most recent status
1575: into the status file.
1576:
1577: We also use this to reset the retries count in order to allow the
1578: client to retry connections with a previously dead server.
1579:
1580: =cut
1581:
1582: sub ChildStatus {
1583: my $event = shift;
1584: my $watcher = $event->w;
1585:
1586: Debug(2, "Reporting child status because : ".$watcher->data);
1587: my $docdir = $perlvar{'lonDocRoot'};
1588:
1589: open(LOG,">>$docdir/lon-status/loncstatus.txt");
1590: flock(LOG,LOCK_EX);
1591: print LOG $$."\t".$RemoteHost."\t".$Status."\t".
1592: $RecentLogEntry."\n";
1593: #
1594: # Write out information about each of the connections:
1595: #
1596: if ($DebugLevel > 2) {
1597: print LOG "Active connection statuses: \n";
1598: my $i = 1;
1599: print STDERR "================================= Socket Status Dump:\n";
1600: foreach my $item (keys %ActiveConnections) {
1601: my $Socket = $ActiveConnections{$item}->data;
1602: my $state = $Socket->GetState();
1603: print LOG "Connection $i State: $state\n";
1604: print STDERR "---------------------- Connection $i \n";
1605: $Socket->Dump(-1); # Ensure it gets dumped..
1606: $i++;
1607: }
1608: }
1609: flock(LOG,LOCK_UN);
1610: close(LOG);
1611: $ConnectionRetriesLeft = $ConnectionRetries;
1612: UpdateStatus();
1613: }
1614:
1615: =pod
1616:
1617: =head2 SignalledToDeath
1618:
1619: Called in response to a signal that causes a chid process to die.
1620:
1621: =cut
1622:
1623:
1624: sub SignalledToDeath {
1625: my $event = shift;
1626: my $watcher= $event->w;
1627:
1628: Debug(2,"Signalled to death! via ".$watcher->data);
1629: my ($signal) = $watcher->data;
1630: chomp($signal);
1631: Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "
1632: ."died through "."\"$signal\"");
1633: #LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
1634: # ."\"$signal\"");
1635: exit 0;
1636:
1637: }
1638:
1639: =pod
1640:
1641: =head2 ToggleDebug
1642:
1643: This sub toggles trace debugging on and off.
1644:
1645: =cut
1646:
1647: sub ToggleDebug {
1648: my $Current = $DebugLevel;
1649: $DebugLevel = $NextDebugLevel;
1650: $NextDebugLevel = $Current;
1651:
1652: Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
1653:
1654: }
1655:
1656: =pod
1657:
1658: =head2 ChildProcess
1659:
1660: This sub implements a child process for a single lonc daemon.
1661: Optional parameter:
1662: $socket - if provided, this is a socket already open for listen
1663: on the client socket. Otherwise, a new listen is set up.
1664:
1665: =cut
1666:
1667: sub ChildProcess {
1668: # If we are in DieWhenIdle mode, we've inherited all the
1669: # events of our parent and those have to be cancelled or else
1670: # all holy bloody chaos will result.. trust me, I already made
1671: # >that< mistake.
1672:
1673: my $host = GetServerHost();
1674: foreach my $listener (keys %parent_dispatchers) {
1675: my $watcher = $parent_dispatchers{$listener};
1676: my $s = $watcher->fd;
1677: if ($listener ne $host) { # Close everyone but me.
1678: Debug(5, "Closing listen socket for $listener");
1679: $s->close();
1680: }
1681: Debug(5, "Killing watcher for $listener");
1682:
1683: $watcher->cancel();
1684: delete($parent_dispatchers{$listener});
1685:
1686: }
1687:
1688: # kill off the parent's signal handlers too!
1689: #
1690:
1691: for my $handler (keys %parent_handlers) {
1692: my $watcher = $parent_handlers{$handler};
1693: $watcher->cancel();
1694: delete($parent_handlers{$handler});
1695: }
1696:
1697: $I_am_child = 1; # Seems like in spite of it all I may still getting
1698: # parent event dispatches.. flag I'm a child.
1699:
1700:
1701: #
1702: # Signals must be handled by the Event framework...
1703: #
1704:
1705: Event->signal(signal => "QUIT",
1706: cb => \&SignalledToDeath,
1707: data => "QUIT");
1708: Event->signal(signal => "HUP",
1709: cb => \&ChildStatus,
1710: data => "HUP");
1711: Event->signal(signal => "USR1",
1712: cb => \&ChildStatus,
1713: data => "USR1");
1714: Event->signal(signal => "USR2",
1715: cb => \&ToggleTransactionLogging);
1716: Event->signal(signal => "INT",
1717: cb => \&ToggleDebug,
1718: data => "INT");
1719:
1720: # Figure out if we got passed a socket or need to open one to listen for
1721: # client requests.
1722:
1723: my ($socket) = @_;
1724: if (!$socket) {
1725:
1726: $socket = SetupLoncListener();
1727: }
1728: # Establish an event to listen for client connection requests.
1729:
1730:
1731: Event->io(cb => \&NewClient,
1732: poll => 'r',
1733: desc => 'Lonc Listener Unix Socket',
1734: fd => $socket);
1735:
1736: $Event::DebugLevel = $DebugLevel;
1737:
1738: Debug(9, "Making initial lond connection for ".$RemoteHost);
1739:
1740: # Setup the initial server connection:
1741:
1742: # &MakeLondConnection(); // let first work request do it.
1743:
1744: # If We are in diwhenidle, need to accept the connection since the
1745: # event may not fire.
1746:
1747: if ($DieWhenIdle) {
1748: &accept_client($socket);
1749: }
1750:
1751: Debug(9,"Entering event loop");
1752: my $ret = Event::loop(); # Start the main event loop.
1753:
1754:
1755: &child_exit (-1,"Main event loop exited!!!");
1756: }
1757:
1758: # Create a new child for host passed in:
1759:
1760: sub CreateChild {
1761: my ($host, $socket) = @_;
1762:
1763: my $sigset = POSIX::SigSet->new(SIGINT);
1764: sigprocmask(SIG_BLOCK, $sigset);
1765: $RemoteHost = $host;
1766: Log("CRITICAL", "Forking server for ".$host);
1767: my $pid = fork;
1768: if($pid) { # Parent
1769: $RemoteHost = "Parent";
1770: $ChildHash{$pid} = $host;
1771: $HostToPid{$host}= $pid;
1772: sigprocmask(SIG_UNBLOCK, $sigset);
1773:
1774: } else { # child.
1775: ShowStatus("Connected to ".$RemoteHost);
1776: $SIG{INT} = 'DEFAULT';
1777: sigprocmask(SIG_UNBLOCK, $sigset);
1778: if(defined $socket) {
1779: &ChildProcess($socket);
1780: } else {
1781: ChildProcess; # Does not return.
1782: }
1783: }
1784: }
1785:
1786: # parent_client_connection:
1787: # Event handler that processes client connections for the parent process.
1788: # This sub is called when the parent is listening on a socket and
1789: # a connection request arrives. We must:
1790: # Start a child process to accept the connection request.
1791: # Kill our listen on the socket.
1792: # Parameter:
1793: # event - The event object that was created to monitor this socket.
1794: # event->w->fd is the socket.
1795: # Returns:
1796: # NONE
1797: #
1798: sub parent_client_connection {
1799: if ($I_am_child) {
1800: # Should not get here, but seem to anyway:
1801: &Debug(5," Child caught parent client connection event!!");
1802: my ($event) = @_;
1803: my $watcher = $event->w;
1804: $watcher->cancel(); # Try to kill it off again!!
1805: } else {
1806: &Debug(9, "parent_client_connection");
1807: my ($event) = @_;
1808: my $watcher = $event->w;
1809: my $socket = $watcher->fd;
1810: if ($hosts_tab) {
1811:
1812: # Lookup the host associated with this socket:
1813:
1814: my $host = $listening_to{$socket};
1815:
1816: # Start the child:
1817:
1818:
1819:
1820: &Debug(9,"Creating child for $host (parent_client_connection)");
1821: &CreateChild($host, $socket);
1822:
1823: # Clean up the listen since now the child takes over until it exits.
1824:
1825: $watcher->cancel(); # Nolonger listening to this event
1826: delete($listening_to{$socket});
1827: delete($parent_dispatchers{$host});
1828: $socket->close();
1829:
1830: } else {
1831: my $connection = $socket->accept(); # Accept the client connection.
1832: Event->io(cb => \&get_remote_hostname,
1833: poll => 'r',
1834: data => "",
1835: fd => $connection);
1836: }
1837: }
1838: }
1839:
1840: sub get_remote_hostname {
1841: my ($event) = @_;
1842: my $watcher = $event->w;
1843: my $socket = $watcher->fd;
1844:
1845: my $thisread;
1846: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1847: Debug(8, "rcv: data length = ".length($thisread)." read =".$thisread);
1848: if (!defined($rv) || length($thisread) == 0) {
1849: # Likely eof on socket.
1850: Debug(5,"Client Socket closed on lonc for p_c_c");
1851: close($socket);
1852: $watcher->cancel();
1853: return;
1854: }
1855:
1856: my $data = $watcher->data().$thisread;
1857: $watcher->data($data);
1858: if($data =~ /\n$/) { # Request entirely read.
1859: chomp($data);
1860: } else {
1861: return;
1862: }
1863:
1864: &Debug(5,"Creating child for $data (parent_client_connection)");
1865: &CreateChild($data);
1866:
1867: # Clean up the listen since now the child takes over until it exits.
1868: $watcher->cancel(); # Nolonger listening to this event
1869: $socket->send("done\n");
1870: $socket->close();
1871: }
1872:
1873: # parent_listen:
1874: # Opens a socket and starts a listen for the parent process on a client UNIX
1875: # domain socket.
1876: #
1877: # This involves:
1878: # Creating a socket for listen.
1879: # Removing any socket lock file
1880: # Adding an event handler for this socket becoming readable
1881: # To the parent's event dispatcher.
1882: # Parameters:
1883: # loncapa_host - LonCAPA cluster name of the host represented by the client
1884: # socket.
1885: # Returns:
1886: # NONE
1887: #
1888: sub parent_listen {
1889: my ($loncapa_host) = @_;
1890: Debug(5, "parent_listen: $loncapa_host");
1891:
1892: my ($socket,$file);
1893: if (!$loncapa_host) {
1894: $loncapa_host = 'common_parent';
1895: $file = $perlvar{'lonSockCreate'};
1896: } else {
1897: $file = &GetLoncSocketPath($loncapa_host);
1898: }
1899: $socket = &SetupLoncListener($loncapa_host,$file);
1900:
1901: $listening_to{$socket} = $loncapa_host;
1902: if (!$socket) {
1903: die "Unable to create a listen socket for $loncapa_host";
1904: }
1905:
1906: my $lock_file = $file.".lock";
1907: unlink($lock_file); # No problem if it doesn't exist yet [startup e.g.]
1908:
1909: my $watcher =
1910: Event->io(cb => \&parent_client_connection,
1911: poll => 'r',
1912: desc => "Parent listener unix socket ($loncapa_host)",
1913: data => "",
1914: fd => $socket);
1915: $parent_dispatchers{$loncapa_host} = $watcher;
1916:
1917: }
1918:
1919: sub parent_clean_up {
1920: my ($loncapa_host) = @_;
1921: Debug(5, "parent_clean_up: $loncapa_host");
1922:
1923: my $socket_file = &GetLoncSocketPath($loncapa_host);
1924: unlink($socket_file); # No problem if it doesn't exist yet [startup e.g.]
1925: my $lock_file = $socket_file.".lock";
1926: unlink($lock_file); # No problem if it doesn't exist yet [startup e.g.]
1927: }
1928:
1929:
1930: # listen_on_all_unix_sockets:
1931: # This sub initiates a listen on all unix domain lonc client sockets.
1932: # This will be called in the case where we are trimming idle processes.
1933: # When idle processes are trimmed, loncnew starts up with no children,
1934: # and only spawns off children when a connection request occurs on the
1935: # client unix socket. The spawned child continues to run until it has
1936: # been idle a while at which point it eventually exits and once more
1937: # the parent picks up the listen.
1938: #
1939: # Parameters:
1940: # NONE
1941: # Implicit Inputs:
1942: # The configuration file that has been read in by LondConnection.
1943: # Returns:
1944: # NONE
1945: #
1946: sub listen_on_all_unix_sockets {
1947: Debug(5, "listen_on_all_unix_sockets");
1948: my $host_iterator = &LondConnection::GetHostIterator();
1949: while (!$host_iterator->end()) {
1950: my $host_entry_ref = $host_iterator->get();
1951: my $host_name = $host_entry_ref->[3];
1952: Debug(9, "Listen for $host_name");
1953: &parent_listen($host_name);
1954: $host_iterator->next();
1955: }
1956: }
1957:
1958: sub listen_on_common_socket {
1959: Debug(5, "listen_on_common_socket");
1960: &parent_listen();
1961: }
1962:
1963: # server_died is called whenever a child process exits.
1964: # Since this is dispatched via a signal, we must process all
1965: # dead children until there are no more left. The action
1966: # is to:
1967: # - Remove the child from the bookeeping hashes
1968: # - Re-establish a listen on the unix domain socket associated
1969: # with that host.
1970: # Parameters:
1971: # The event, but we don't actually care about it.
1972: sub server_died {
1973: &Debug(9, "server_died called...");
1974:
1975: while(1) { # Loop until waitpid nowait fails.
1976: my $pid = waitpid(-1, WNOHANG);
1977: if($pid <= 0) {
1978: return; # Nothing left to wait for.
1979: }
1980: # need the host to restart:
1981:
1982: my $host = $ChildHash{$pid};
1983: if($host) { # It's for real...
1984: &Debug(9, "Caught sigchild for $host");
1985: delete($ChildHash{$pid});
1986: delete($HostToPid{$host});
1987: if ($hosts_tab) {
1988: &parent_listen($host);
1989: } else {
1990: &parent_clean_up($host);
1991: }
1992:
1993: } else {
1994: &Debug(5, "Caught sigchild for pid not in hosts hash: $pid");
1995: }
1996: }
1997:
1998: }
1999:
2000: #
2001: # Parent process logic pass 1:
2002: # For each entry in the hosts table, we will
2003: # fork off an instance of ChildProcess to service the transactions
2004: # to that host. Each pid will be entered in a global hash
2005: # with the value of the key, the host.
2006: # The parent will then enter a loop to wait for process exits.
2007: # Each exit gets logged and the child gets restarted.
2008: #
2009:
2010: #
2011: # Fork and start in new session so hang-up isn't going to
2012: # happen without intent.
2013: #
2014:
2015:
2016:
2017:
2018:
2019:
2020: ShowStatus("Forming new session");
2021: my $childpid = fork;
2022: if ($childpid != 0) {
2023: sleep 4; # Give child a chacne to break to
2024: exit 0; # a new sesion.
2025: }
2026: #
2027: # Write my pid into the pid file so I can be located
2028: #
2029:
2030: ShowStatus("Parent writing pid file:");
2031: my $execdir = $perlvar{'lonDaemons'};
2032: open (PIDSAVE, ">$execdir/logs/lonc.pid");
2033: print PIDSAVE "$$\n";
2034: close(PIDSAVE);
2035:
2036:
2037:
2038: if (POSIX::setsid() < 0) {
2039: print "Could not create new session\n";
2040: exit -1;
2041: }
2042:
2043: ShowStatus("Forking node servers");
2044:
2045: Log("CRITICAL", "--------------- Starting children ---------------");
2046:
2047: LondConnection::ReadConfig; # Read standard config files.
2048: my $HostIterator = LondConnection::GetHostIterator;
2049:
2050: if ($DieWhenIdle) {
2051: $RemoteHost = "[parent]";
2052: if ($hosts_tab) {
2053: &listen_on_all_unix_sockets();
2054: } else {
2055: &listen_on_common_socket();
2056: }
2057: } else {
2058:
2059: while (! $HostIterator->end()) {
2060:
2061: my $hostentryref = $HostIterator->get();
2062: CreateChild($hostentryref->[0]);
2063: $HostHash{$hostentryref->[0]} = $hostentryref->[4];
2064: $HostIterator->next();
2065: }
2066: }
2067:
2068: $RemoteHost = "Parent Server";
2069:
2070: # Maintain the population:
2071:
2072: ShowStatus("Parent keeping the flock");
2073:
2074:
2075: if ($DieWhenIdle) {
2076: # We need to setup a SIGChild event to handle the exit (natural or otherwise)
2077: # of the children.
2078:
2079: Event->signal(cb => \&server_died,
2080: desc => "Child exit handler",
2081: signal => "CHLD");
2082:
2083:
2084: # Set up all the other signals we set up. We'll vector them off to the
2085: # same subs as we would for DieWhenIdle false and, if necessary, conditionalize
2086: # the code there.
2087:
2088: $parent_handlers{INT} = Event->signal(cb => \&Terminate,
2089: desc => "Parent INT handler",
2090: signal => "INT");
2091: $parent_handlers{TERM} = Event->signal(cb => \&Terminate,
2092: desc => "Parent TERM handler",
2093: signal => "TERM");
2094: if ($hosts_tab) {
2095: $parent_handlers{HUP} = Event->signal(cb => \&Restart,
2096: desc => "Parent HUP handler.",
2097: signal => "HUP");
2098: } else {
2099: $parent_handlers{HUP} = Event->signal(cb => \&KillThemAll,
2100: desc => "Parent HUP handler.",
2101: signal => "HUP");
2102: }
2103: $parent_handlers{USR1} = Event->signal(cb => \&CheckKids,
2104: desc => "Parent USR1 handler",
2105: signal => "USR1");
2106: $parent_handlers{USR2} = Event->signal(cb => \&UpdateKids,
2107: desc => "Parent USR2 handler.",
2108: signal => "USR2");
2109:
2110: # Start procdesing events.
2111:
2112: $Event::DebugLevel = $DebugLevel;
2113: Debug(9, "Parent entering event loop");
2114: my $ret = Event::loop();
2115: die "Main Event loop exited: $ret";
2116:
2117:
2118: } else {
2119: #
2120: # Set up parent signals:
2121: #
2122:
2123: $SIG{INT} = \&Terminate;
2124: $SIG{TERM} = \&Terminate;
2125: if ($hosts_tab) {
2126: $SIG{HUP} = \&Restart;
2127: } else {
2128: $SIG{HUP} = \&KillThemAll;
2129: }
2130: $SIG{USR1} = \&CheckKids;
2131: $SIG{USR2} = \&UpdateKids; # LonManage update request.
2132:
2133: while(1) {
2134: my $deadchild = wait();
2135: if(exists $ChildHash{$deadchild}) { # need to restart.
2136: my $deadhost = $ChildHash{$deadchild};
2137: delete($HostToPid{$deadhost});
2138: delete($ChildHash{$deadchild});
2139: Log("WARNING","Lost child pid= ".$deadchild.
2140: "Connected to host ".$deadhost);
2141: Log("INFO", "Restarting child procesing ".$deadhost);
2142: CreateChild($deadhost);
2143: }
2144: }
2145: }
2146:
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 %ChildHash) {
2171: Debug(2, "Sending USR1 -> $pid");
2172: kill 'USR1' => $pid; # Tell Child to report status.
2173: }
2174:
2175: }
2176:
2177: =pod
2178:
2179: =head1 UpdateKids
2180:
2181: parent's SIGUSR2 handler. This handler:
2182:
2183: =item
2184:
2185: Rereads the hosts file.
2186:
2187: =item
2188:
2189: Kills off (via sigint) children for hosts that have disappeared.
2190:
2191: =item
2192:
2193: QUITs children for hosts that already exist (this just forces a status display
2194: and resets the connection retry count for that host.
2195:
2196: =item
2197:
2198: Starts new children for hosts that have been added to the hosts.tab file since
2199: the start of the master program and maintains them.
2200:
2201: =cut
2202:
2203: sub UpdateKids {
2204:
2205: Log("INFO", "Updating connections via SIGUSR2");
2206:
2207: # I'm not sure what I was thinking in the first implementation.
2208: # someone will have to work hard to convince me the effect is any
2209: # different than Restart, especially now that we don't start up
2210: # per host servers automatically, may as well just restart.
2211: # The down side is transactions that are in flight will get timed out
2212: # (lost unless they are critical).
2213:
2214: if ($hosts_tab) {
2215: &Restart();
2216: } else {
2217: &KillThemAll();
2218: }
2219: }
2220:
2221:
2222: =pod
2223:
2224: =head1 Restart
2225:
2226: Signal handler for HUP... all children are killed and
2227: we self restart. This is an el-cheapo way to re read
2228: the config file.
2229:
2230: =cut
2231:
2232: sub Restart {
2233: &KillThemAll; # First kill all the children.
2234: Log("CRITICAL", "Restarting");
2235: my $execdir = $perlvar{'lonDaemons'};
2236: unlink("$execdir/logs/lonc.pid");
2237: exec("$executable");
2238: }
2239:
2240: =pod
2241:
2242: =head1 KillThemAll
2243:
2244: Signal handler that kills all children by sending them a
2245: SIGHUP. Responds to sigint and sigterm.
2246:
2247: =cut
2248:
2249: sub KillThemAll {
2250: Debug(2, "Kill them all!!");
2251: local($SIG{CHLD}) = 'IGNORE'; # Our children >will< die.
2252: foreach my $pid (keys %ChildHash) {
2253: my $serving = $ChildHash{$pid};
2254: ShowStatus("Nicely Killing lonc for $serving pid = $pid");
2255: Log("CRITICAL", "Nicely Killing lonc for $serving pid = $pid");
2256: kill 'QUIT' => $pid;
2257: }
2258: }
2259:
2260:
2261: #
2262: # Kill all children via KILL. Just in case the
2263: # first shot didn't get them.
2264:
2265: sub really_kill_them_all_dammit
2266: {
2267: Debug(2, "Kill them all Dammit");
2268: local($SIG{CHLD} = 'IGNORE'); # In case some purist reenabled them.
2269: foreach my $pid (keys %ChildHash) {
2270: my $serving = $ChildHash{$pid};
2271: &ShowStatus("Nastily killing lonc for $serving pid = $pid");
2272: Log("CRITICAL", "Nastily killing lonc for $serving pid = $pid");
2273: kill 'KILL' => $pid;
2274: delete($ChildHash{$pid});
2275: my $execdir = $perlvar{'lonDaemons'};
2276: unlink("$execdir/logs/lonc.pid");
2277: }
2278: }
2279:
2280: =pod
2281:
2282: =head1 Terminate
2283:
2284: Terminate the system.
2285:
2286: =cut
2287:
2288: sub Terminate {
2289: &Log("CRITICAL", "Asked to kill children.. first be nice...");
2290: &KillThemAll;
2291: #
2292: # By now they really should all be dead.. but just in case
2293: # send them all SIGKILL's after a bit of waiting:
2294:
2295: sleep(4);
2296: &Log("CRITICAL", "Now kill children nasty");
2297: &really_kill_them_all_dammit;
2298: Log("CRITICAL","Master process exiting");
2299: exit 0;
2300:
2301: }
2302: =pod
2303:
2304: =head1 Theory
2305:
2306: The event class is used to build this as a single process with an
2307: event driven model. The following events are handled:
2308:
2309: =item UNIX Socket connection Received
2310:
2311: =item Request data arrives on UNIX data transfer socket.
2312:
2313: =item lond connection becomes writable.
2314:
2315: =item timer fires at 1 second intervals.
2316:
2317: All sockets are run in non-blocking mode. Timeouts managed by the timer
2318: handler prevents hung connections.
2319:
2320: Key data structures:
2321:
2322: =item RequestQueue
2323:
2324: A queue of requests received from UNIX sockets that are
2325: waiting for a chance to be forwarded on a lond connection socket.
2326:
2327: =item ActiveConnections
2328:
2329: A hash of lond connections that have transactions in process that are
2330: available to be timed out.
2331:
2332: =item ActiveTransactions
2333:
2334: A hash indexed by lond connections that contain the client reply
2335: socket for each connection that has an active transaction on it.
2336:
2337: =item IdleConnections
2338:
2339: A hash of lond connections that have no work to do. These connections
2340: can be closed if they are idle for a long enough time.
2341:
2342: =cut
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