1: #!/usr/bin/perl
2:
3: # The LearningOnline Network
4: # lonc - LON TCP-Client Domain-Socket-Server
5: # provides persistent TCP connections to the other servers in the network
6: # through multiplexed domain sockets
7: #
8: # $Id: lonc,v 1.36 2002/03/27 04:07:02 foxr Exp $
9: #
10: # Copyright Michigan State University Board of Trustees
11: #
12: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
13: #
14: # LON-CAPA is free software; you can redistribute it and/or modify
15: # it under the terms of the GNU General Public License as published by
16: # the Free Software Foundation; either version 2 of the License, or
17: # (at your option) any later version.
18: #
19: # LON-CAPA is distributed in the hope that it will be useful,
20: # but WITHOUT ANY WARRANTY; without even the implied warranty of
21: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22: # GNU General Public License for more details.
23: #
24: # You should have received a copy of the GNU General Public License
25: # along with LON-CAPA; if not, write to the Free Software
26: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
27: #
28: # /home/httpd/html/adm/gpl.txt
29: #
30: # http://www.lon-capa.org/
31: #
32: # PID in subdir logs/lonc.pid
33: # kill kills
34: # HUP restarts
35: # USR1 tries to open connections again
36:
37: # 6/4/99,6/5,6/7,6/8,6/9,6/10,6/11,6/12,7/14,7/19,
38: # 10/8,10/9,10/15,11/18,12/22,
39: # 2/8,7/25 Gerd Kortemeyer
40: # 12/05 Scott Harrison
41: # 12/05 Gerd Kortemeyer
42: # YEAR=2001
43: # 01/10/01 Scott Harrison
44: # 03/14/01,03/15,06/12,11/26,11/27,11/28 Gerd Kortemeyer
45: # 12/20 Scott Harrison
46: # YEAR=2002
47: # 2/19/02,02/22/02,02/25/02 Gerd Kortemeyer
48: # 3/07/02 Ron Fox
49: # based on nonforker from Perl Cookbook
50: # - server who multiplexes without forking
51:
52: use POSIX;
53: use IO::Socket;
54: use IO::Select;
55: use IO::File;
56: use Socket;
57: use Fcntl;
58: use Tie::RefHash;
59: use Crypt::IDEA;
60: #use Net::Ping;
61: use LWP::UserAgent();
62:
63: $status='';
64: $lastlog='';
65: $conserver='SHELL';
66: $DEBUG = 0; # Set to 1 for annoyingly complete logs.
67:
68: # -------------------------------- Set signal handlers to record abnormal exits
69:
70: &status("Init exception handlers");
71: $SIG{QUIT}=\&catchexception;
72: $SIG{__DIE__}=\&catchexception;
73:
74: # ------------------------------------ Read httpd access.conf and get variables
75: &status("Read access.conf");
76: open (CONFIG,"/etc/httpd/conf/access.conf") || die "Can't read access.conf";
77:
78: while ($configline=<CONFIG>) {
79: if ($configline =~ /PerlSetVar/) {
80: my ($dummy,$varname,$varvalue)=split(/\s+/,$configline);
81: chomp($varvalue);
82: $perlvar{$varname}=$varvalue;
83: }
84: }
85: close(CONFIG);
86:
87: # ----------------------------- Make sure this process is running from user=www
88: &status("Check user ID");
89: my $wwwid=getpwnam('www');
90: if ($wwwid!=$<) {
91: $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
92: $subj="LON: $perlvar{'lonHostID'} User ID mismatch";
93: system("echo 'User ID mismatch. lonc must be run as user www.' |\
94: mailto $emailto -s '$subj' > /dev/null");
95: exit 1;
96: }
97:
98: # --------------------------------------------- Check if other instance running
99:
100: my $pidfile="$perlvar{'lonDaemons'}/logs/lonc.pid";
101:
102: if (-e $pidfile) {
103: my $lfh=IO::File->new("$pidfile");
104: my $pide=<$lfh>;
105: chomp($pide);
106: if (kill 0 => $pide) { die "already running"; }
107: }
108:
109: # ------------------------------------------------------------- Read hosts file
110:
111: open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
112:
113: while ($configline=<CONFIG>) {
114: my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
115: chomp($ip);
116: if ($ip) {
117: $hostip{$id}=$ip;
118: $hostname{$id}=$name;
119: }
120: }
121:
122: close(CONFIG);
123:
124: # -------------------------------------------------------- Routines for forking
125:
126: %children = (); # keys are current child process IDs,
127: # values are hosts
128: %childpid = (); # the other way around
129:
130: %childatt = (); # number of attempts to start server
131: # for ID
132:
133: $childmaxattempts=5;
134:
135: # ---------------------------------------------------- Fork once and dissociate
136: &status("Fork and dissociate");
137: $fpid=fork;
138: exit if $fpid;
139: die "Couldn't fork: $!" unless defined ($fpid);
140:
141: POSIX::setsid() or die "Can't start new session: $!";
142:
143: $conserver='PARENT';
144:
145: # ------------------------------------------------------- Write our PID on disk
146: &status("Write PID");
147: $execdir=$perlvar{'lonDaemons'};
148: open (PIDSAVE,">$execdir/logs/lonc.pid");
149: print PIDSAVE "$$\n";
150: close(PIDSAVE);
151: &logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
152:
153: # ----------------------------- Ignore signals generated during initial startup
154: $SIG{HUP}=$SIG{USR1}='IGNORE';
155: # ------------------------------------------------------- Now we are on our own
156:
157: # Fork off our children, one for every server
158:
159: &status("Forking ...");
160:
161: foreach $thisserver (keys %hostip) {
162: #if (&online($hostname{$thisserver})) {
163: make_new_child($thisserver);
164: #}
165: }
166:
167: &logthis("Done starting initial servers");
168: # ----------------------------------------------------- Install signal handlers
169:
170:
171: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
172: $SIG{HUP} = \&HUPSMAN;
173: $SIG{USR1} = \&USRMAN;
174:
175: # And maintain the population.
176: while (1) {
177: my $deadpid = wait; # Wait for the next child to die.
178: # See who died and start new one
179: &status("Woke up");
180: my $skipping='';
181:
182: if(exists($children{$deadpid})) {
183:
184: $thisserver = $children{$deadpid}; # Look name of dead guy's peer.
185:
186: delete($children{$deadpid}); # Get rid of dead hash entry.
187:
188: if($childatt{$thisserver} < $childmaxattempts) {
189: $childatt{$thisserver}++;
190: &logthis(
191: "<font color=yellow>INFO: Trying to reconnect for $thisserver "
192: ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
193: make_new_child($thisserver);
194:
195: }
196: else {
197: $skipping .= $thisserver.' ';
198: }
199: if($skipping) {
200: &logthis("<font color=blue>WARNING: Skipped $skipping</font>");
201:
202: }
203: }
204:
205: }
206:
207:
208:
209: sub make_new_child {
210:
211: $newserver=shift;
212: my $pid;
213: my $sigset;
214: &logthis("Attempting to start child for server $newserver");
215: # block signal for fork
216: $sigset = POSIX::SigSet->new(SIGINT);
217: sigprocmask(SIG_BLOCK, $sigset)
218: or die "Can't block SIGINT for fork: $!\n";
219:
220: die "fork: $!" unless defined ($pid = fork);
221:
222: if ($pid) {
223: # Parent records the child's birth and returns.
224: sigprocmask(SIG_UNBLOCK, $sigset)
225: or die "Can't unblock SIGINT for fork: $!\n";
226: $children{$pid} = $newserver;
227: $childpid{$newserver} = $pid;
228: return;
229: } else {
230: $conserver=$newserver;
231: # Child can *not* return from this subroutine.
232: $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
233: $SIG{USR1}= \&logstatus;
234:
235: # unblock signals
236: sigprocmask(SIG_UNBLOCK, $sigset)
237: or die "Can't unblock SIGINT for fork: $!\n";
238:
239: # ----------------------------- This is the modified main program of non-forker
240:
241: $port = "$perlvar{'lonSockDir'}/$conserver";
242:
243: unlink($port);
244:
245: # -------------------------------------------------------------- Open other end
246:
247: &openremote($conserver);
248: &logthis("<font color=green> Connection to $conserver open </font>");
249: # ----------------------------------------- We're online, send delayed messages
250: &status("Checking for delayed messages");
251:
252: my @allbuffered;
253: my $path="$perlvar{'lonSockDir'}/delayed";
254: opendir(DIRHANDLE,$path);
255: @allbuffered=grep /\.$conserver$/, readdir DIRHANDLE;
256: closedir(DIRHANDLE);
257: my $dfname;
258: foreach (@allbuffered) {
259: &status("Sending delayed: $_");
260: $dfname="$path/$_";
261: if($DEBUG) { &logthis('Sending '.$dfname); }
262: my $wcmd;
263: {
264: my $dfh=IO::File->new($dfname);
265: $cmd=<$dfh>;
266: }
267: chomp($cmd);
268: my $bcmd=$cmd;
269: if ($cmd =~ /^encrypt\:/) {
270: my $rcmd=$cmd;
271: $rcmd =~ s/^encrypt\://;
272: chomp($rcmd);
273: my $cmdlength=length($rcmd);
274: $rcmd.=" ";
275: my $encrequest='';
276: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
277: $encrequest.=
278: unpack("H16",$cipher->encrypt(substr($rcmd,$encidx,8)));
279: }
280: $cmd="enc:$cmdlength:$encrequest\n";
281: }
282: $answer = londtransaction($remotesock, $cmd, 60);
283: chomp($answer);
284:
285: if (($answer ne '') && ($@!~/timeout/)) {
286: unlink("$dfname");
287: &logthis("Delayed $cmd: >$answer<");
288: &logperm("S:$conserver:$bcmd");
289: }
290: }
291: if($DEBUG) { &logthis("<font color=green> Delayed transactions sent"); }
292:
293: # ------------------------------------------------------- Listen to UNIX socket
294: &status("Opening socket");
295: unless (
296: $server = IO::Socket::UNIX->new(Local => $port,
297: Type => SOCK_STREAM,
298: Listen => 10 )
299: ) {
300: my $st=120+int(rand(240));
301: &logthis(
302: "<font color=blue>WARNING: ".
303: "Can't make server socket ($st secs): .. exiting</font>");
304: sleep($st);
305: exit;
306: };
307:
308: # -----------------------------------------------------------------------------
309:
310: &logthis("<font color=green>$conserver online</font>");
311:
312: # -----------------------------------------------------------------------------
313: # begin with empty buffers
314: %inbuffer = ();
315: %outbuffer = ();
316: %ready = ();
317: %servers = (); # To be compatible with make filevector. indexed by
318: # File descriptors, values are file descriptors.
319: # note that the accept socket is omitted.
320:
321: tie %ready, 'Tie::RefHash';
322:
323: nonblock($server);
324: $select = IO::Select->new($server);
325:
326: # Main loop: check reads/accepts, check writes, check ready to process
327: while (1) {
328: my $client;
329: my $rv;
330: my $data;
331:
332: my $infdset; # bit vec of fd's to select on input.
333: my $inreadyset; # Bit vec of fd's ready for input.
334:
335: my $outfdset; # Bit vec of fd's to select on output.
336: my $outreadyset; # bit vec of fds ready for output.
337:
338:
339: $infdset = MakeFileVector(\%servers);
340: $outfdset= MakeFileVector(\%outbuffer);
341:
342: # check for new information on the connections we have
343: # anything to read or accept?
344:
345: foreach $client ($select->can_read(00.10)) {
346: if ($client == $server) {
347: # accept a new connection
348: &status("Accept new connection: $conserver");
349: $client = $server->accept();
350: $select->add($client);
351: nonblock($client);
352: } else {
353: # read data
354: $data = '';
355: $rv = $client->recv($data, POSIX::BUFSIZ, 0);
356:
357: unless (defined($rv) && length $data) {
358: # This would be the end of file, so close the client
359: delete $inbuffer{$client};
360: delete $outbuffer{$client};
361: delete $ready{$client};
362:
363: &status("Idle");
364: $select->remove($client);
365: close $client;
366: next;
367: }
368:
369: $inbuffer{$client} .= $data;
370:
371:
372: # test whether the data in the buffer or the data we
373: # just read means there is a complete request waiting
374: # to be fulfilled. If there is, set $ready{$client}
375: # to the requests waiting to be fulfilled.
376: while ($inbuffer{$client} =~ s/(.*\n)//) {
377: push( @{$ready{$client}}, $1 );
378: }
379: }
380: }
381:
382: # Any complete requests to process?
383: foreach $client (keys %ready) {
384: handle($client);
385: }
386:
387: # Buffers to flush?
388: foreach $client ($select->can_write(1)) {
389: # Skip this client if we have nothing to say
390: next unless exists $outbuffer{$client};
391:
392: $rv = $client->send($outbuffer{$client}, 0);
393:
394: unless ($outbuffer{$client} eq "con_lost\n") {
395: unless (defined $rv) {
396: # Whine, but move on.
397: &logthis("I was told I could write, but I can't.\n");
398: next;
399: }
400: $errno=$!;
401: if (($rv == length $outbuffer{$client}) ||
402: ($errno == POSIX::EWOULDBLOCK) || ($errno == 0)) {
403: substr($outbuffer{$client}, 0, $rv) = '';
404: delete $outbuffer{$client} unless length $outbuffer{$client};
405: } else {
406: # Couldn't write all the data, and it wasn't because
407: # it would have blocked. Shutdown and move on.
408:
409: &logthis("Dropping data with ".$errno.": ".
410: length($outbuffer{$client}).", $rv");
411:
412: delete $inbuffer{$client};
413: delete $outbuffer{$client};
414: delete $ready{$client};
415:
416: $select->remove($client);
417: close($client);
418: next;
419: }
420: } else {
421: # -------------------------------------------------------- Wow, connection lost
422: &logthis(
423: "<font color=red>CRITICAL: Closing connection</font>");
424: &status("Connection lost");
425: $remotesock->shutdown(2);
426: &logthis("Attempting to open new connection");
427: &openremote($conserver);
428: }
429: }
430:
431: }
432: }
433:
434: # ------------------------------------------------------- End of make_new_child
435:
436:
437: #
438: # Make a vector of file descriptors to wait for in a select.
439: # parameters:
440: # \%fdhash -reference to a hash which has IO::Socket's as indices.
441: # We only care about the indices, not the values.
442: # A select vector is created from all indices of the hash.
443:
444: sub MakeFileVector
445: {
446: my $fdhash = shift;
447: my $selvar = "";
448:
449: foreach $socket (keys %fdhash) {
450: vec($selvar, ($fdhash->{$socket})->fileno, 1) = 1;
451: }
452: return $selvar;
453: }
454:
455:
456: #
457: # HandleOutput:
458: # Processes output on a buffered set of file descriptors which are
459: # ready to be read.
460: # Parameters:
461: # $selvector - Vector of writable file descriptors which are writable.
462: # \%sockets - Vector of socket references indexed by socket.
463: # \%buffers - Reference to a hash containing output buffers.
464: # Hashes are indexed by sockets. The file descriptors of some
465: # of those sockets will be present in $selvector.
466: # For each one of those, we will attempt to write the output
467: # buffer to the socket. Note that we will assume that
468: # the sockets are being run in non blocking mode.
469: # \%inbufs - Reference to hash containing input buffers.
470: # \%readys - Reference to hash containing flags for items with complete
471: # requests.
472: #
473: sub HandleOutput
474: {
475: my $selvector = shift;
476: my $sockets = shift;
477: my $buffers = shift;
478: my $inbufs = shift;
479: my $readys = shift;
480:
481: foreach $sock (keys %buffers) {
482: my $socket = $sockets->{$sock};
483: if(vec($selvector, $$socket->fileno, 1)) { # $socket is writable.
484: my $rv = $$socket->send($buffers->{$sock}, 0);
485: $errno = $!;
486: unless ($buffers->{$sock} eq "con_lost\n") {
487: unless (defined $rv) { # Write failed... could be EINTR
488: unless ($errno == POSIX::EINTR) {
489: &logthis("Write failed on writable socket");
490: } # EINTR is not an error .. just retry.
491: next;
492: }
493: if( ($rv == length $buffers->{$sock}) ||
494: ($errno == POSIX::EWOULDBLOCK) ||
495: ($errno == POSIX::EAGAIN) || # same as above.
496: ($errno == POSIX::EINTR) || # signal during IO
497: ($errno == 0)) {
498: substr($buffers->{$sock}, 0, $rv)=""; # delete written part
499: delete $buffers->{$sock} unless length $buffers->{$sock};
500: } else {
501: # For some reason the write failed with an error code
502: # we didn't look for. Shutdown the socket.
503: &logthis("Unable to write data with ".$errno.": ".
504: "Dropping data: ".length($buffers->{$sock}).
505: ", $rv");
506: #
507: # kill off the buffers in the hash:
508:
509: delete $buffers->{$sock};
510: delete $inbufs->{$sock};
511: delete $readys->{$sock};
512:
513: close($$socket); # Close the client socket.
514: next;
515: }
516: } else { # Kludgy way to mark lond connection lost.
517: &logthis(
518: "<font color=red>CRITICAL lond connection lost</font>");
519: status("Connection lost");
520: $remotesock->shutdown(2);
521: &logthis("Attempting to open a new connection");
522: &openremot($conserver);
523: }
524:
525: }
526: }
527:
528: }
529: #
530: # HandleInput - Deals with input on client sockets.
531: # Each socket has an associated input buffer.
532: # For each readable socket, the currently available
533: # data is appended to this buffer.
534: # If necessary, the buffer is created.
535: # On various failures, we may shutdown the client.
536: # Parameters:
537: # $selvec - Vector of readable sockets.
538: # \%sockets - Refers to the Hash of sockets indexed by sockets.
539: # Each of these may or may not have it's fd bit set
540: # in the $selvec.
541: # \%ibufs - Refers to the hash of input buffers indexed by socket.
542: # \%obufs - Hash of output buffers indexed by socket.
543: # \%ready - Hash of ready flags indicating the existence of a completed
544: # Request.
545: sub HandleInput
546: {
547:
548: # Marshall the parameters. Note that the hashes are actually
549: # references not values.
550:
551: my $selvec = shift;
552: my $sockets = shift;
553: my $ibufs = shift;
554: my $obufs = shift;
555: my $ready = shift;
556:
557: foreach $sock (keys %sockets) {
558: my $socket = $sockets->{$sock};
559: if(vec($selvec, $$socket->fileno, 1)) { # Socket which is readable.
560:
561: # Attempt to read the data and do error management.
562: my $data = '';
563: my $rv = $$socket->recv($data, POSIX::BUFSIZ, 0);
564: unless (defined($rv) && length $data) {
565:
566: # Read an end of file.. this is a disconnect from the peer.
567:
568: delete $sockets->{$sock};
569: delete $ibufs->{$sock};
570: delete $obufs->{$sock};
571: delete $ready->{$sock};
572:
573: status("Idle");
574: close $$socket;
575: next;
576: }
577: # Append the read data to the input buffer. If the buffer
578: # now contains a \n the request is complete and we can
579: # mark this in the $ready hash (one request for each \n.)
580:
581: $ibufs->{$sock} .= $data;
582: while($ibufs->{$sock} =~ s/(.*\n)//) {
583: push(@{$ready->{$sock}}, $1);
584: }
585:
586: }
587: }
588: # Now handle any requests which are ready:
589:
590: foreach $client (keys %ready) {
591: handle($client);
592: }
593: }
594:
595: # DoSelect: does a select with no timeout. On signal (errno == EINTR),
596: # the select is retried until there are items in the returned
597: # vectors.
598: #
599: # Parameters:
600: # \$readvec - Reference to a vector of file descriptors to
601: # check for readability.
602: # \$writevec - Reference to a vector of file descriptors to check for
603: # writability.
604: # On exit, the referents are modified with vectors indicating which
605: # file handles are readable/writable.
606: #
607: sub DoSelect {
608: my $readvec = shift;
609: my $writevec= shift;
610: my $outs;
611: my $ins;
612:
613: while (1) {
614: my $nfds = select($outs = $$writevec, $ins = $$readvec, undef, undef);
615: if($nfound) {
616: $$readvec = $ins;
617: $$writevec = $outs;
618: return;
619: } else {
620: die "Select failed" unless $! == EINTR;
621: }
622: }
623: }
624:
625: # handle($socket) deals with all pending requests for $client
626: #
627: sub handle {
628: # requests are in $ready{$client}
629: # send output to $outbuffer{$client}
630: my $client = shift;
631: my $request;
632: foreach $request (@{$ready{$client}}) {
633: # ============================================================= Process request
634: # $request is the text of the request
635: # put text of reply into $outbuffer{$client}
636: # ------------------------------------------------------------ Is this the end?
637: chomp($request);
638: if($DEBUG) {
639: &logthis("<font color=green> Request $request processing starts</font>");
640: }
641: if ($request eq "close_connection_exit\n") {
642: &status("Request close connection");
643: &logthis(
644: "<font color=red>CRITICAL: Request Close Connection ... exiting</font>");
645: $remotesock->shutdown(2);
646: $server->close();
647: exit;
648: }
649: # -----------------------------------------------------------------------------
650: if ($request =~ /^encrypt\:/) {
651: my $cmd=$request;
652: $cmd =~ s/^encrypt\://;
653: chomp($cmd);
654: my $cmdlength=length($cmd);
655: $cmd.=" ";
656: my $encrequest='';
657: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
658: $encrequest.=
659: unpack("H16",$cipher->encrypt(substr($cmd,$encidx,8)));
660: }
661: $request="enc:$cmdlength:$encrequest";
662: }
663: # --------------------------------------------------------------- Main exchange
664: $answer = londtransaction($remotesock, $request, 300);
665:
666: if($DEBUG) {
667: &logthis("<font color=green> Request data exchange complete");
668: }
669: if ($@=~/timeout/) {
670: $answer='';
671: &logthis(
672: "<font color=red>CRITICAL: Timeout: $request</font>");
673: }
674:
675:
676: if ($answer) {
677: if ($answer =~ /^enc/) {
678: my ($cmd,$cmdlength,$encinput)=split(/:/,$answer);
679: chomp($encinput);
680: $answer='';
681: for (my $encidx=0;$encidx<length($encinput);$encidx+=16) {
682: $answer.=$cipher->decrypt(
683: pack("H16",substr($encinput,$encidx,16))
684: );
685: }
686: $answer=substr($answer,0,$cmdlength);
687: $answer.="\n";
688: }
689: if($DEBUG) {
690: &logthis("sending $answer to client\n");
691: }
692: $outbuffer{$client} .= $answer;
693: } else {
694: $outbuffer{$client} .= "con_lost\n";
695: }
696:
697: &status("Completed: $request");
698: if($DEBUG) {
699: &logthis("<font color=green> Request processing complete</font>");
700: }
701: # ===================================================== Done processing request
702: }
703: delete $ready{$client};
704: # -------------------------------------------------------------- End non-forker
705: if($DEBUG) {
706: &logthis("<font color=green> requests for child handled</font>");
707: }
708: }
709: # ---------------------------------------------------------- End make_new_child
710: }
711:
712: # nonblock($socket) puts socket into nonblocking mode
713: sub nonblock {
714: my $socket = shift;
715: my $flags;
716:
717:
718: $flags = fcntl($socket, F_GETFL, 0)
719: or die "Can't get flags for socket: $!\n";
720: fcntl($socket, F_SETFL, $flags | O_NONBLOCK)
721: or die "Can't make socket nonblocking: $!\n";
722: }
723:
724:
725: sub openremote {
726: # ---------------------------------------------------- Client to network server
727:
728: my $conserver=shift;
729:
730: &status("Opening TCP");
731: my $st=120+int(rand(240)); # Sleep before opening:
732:
733: unless (
734: $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
735: PeerPort => $perlvar{'londPort'},
736: Proto => "tcp",
737: Type => SOCK_STREAM)
738: ) {
739:
740: &logthis(
741: "<font color=blue>WARNING: Couldn't connect to $conserver ($st secs): </font>");
742: sleep($st);
743: exit;
744: };
745: # ----------------------------------------------------------------- Init dialog
746:
747: &logthis("<font color=green>INFO Connected to $conserver, initing </font>");
748: &status("Init dialogue: $conserver");
749:
750: $answer = londtransaction($remotesock, "init", 60);
751: chomp($answer);
752: $answer = londtransaction($remotesock, $answer, 60);
753: chomp($answer);
754:
755: if ($@=~/timeout/) {
756: &logthis("Timed out during init.. exiting");
757: exit;
758: }
759:
760: if ($answer ne 'ok') {
761: &logthis("Init reply: >$answer<");
762: my $st=120+int(rand(240));
763: &logthis(
764: "<font color=blue>WARNING: Init failed ($st secs)</font>");
765: sleep($st);
766: exit;
767: }
768:
769: sleep 5;
770: &status("Ponging");
771: print $remotesock "pong\n";
772: $answer=<$remotesock>;
773: chomp($answer);
774: if ($answer!~/^$conserver/) {
775: &logthis("Pong reply: >$answer<");
776: }
777: # ----------------------------------------------------------- Initialize cipher
778:
779: &status("Initialize cipher");
780: print $remotesock "ekey\n";
781: my $buildkey=<$remotesock>;
782: my $key=$conserver.$perlvar{'lonHostID'};
783: $key=~tr/a-z/A-Z/;
784: $key=~tr/G-P/0-9/;
785: $key=~tr/Q-Z/0-9/;
786: $key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
787: $key=substr($key,0,32);
788: my $cipherkey=pack("H32",$key);
789: if ($cipher=new IDEA $cipherkey) {
790: &logthis("Secure connection initialized");
791: } else {
792: my $st=120+int(rand(240));
793: &logthis(
794: "<font color=blue>WARNING: ".
795: "Could not establish secure connection ($st secs)!</font>");
796: sleep($st);
797: exit;
798: }
799: &logthis("<font color=green> Remote open success </font>");
800: }
801:
802:
803:
804: # grabs exception and records it to log before exiting
805: sub catchexception {
806: my ($signal)=@_;
807: $SIG{QUIT}='DEFAULT';
808: $SIG{__DIE__}='DEFAULT';
809: chomp($signal);
810: &logthis("<font color=red>CRITICAL: "
811: ."ABNORMAL EXIT. Child $$ for server [$wasserver] died through "
812: ."\"$signal\" with parameter </font>");
813: die("Signal abend");
814: }
815:
816: # -------------------------------------- Routines to see if other box available
817:
818: #sub online {
819: # my $host=shift;
820: # &status("Pinging ".$host);
821: # my $p=Net::Ping->new("tcp",20);
822: # my $online=$p->ping("$host");
823: # $p->close();
824: # undef ($p);
825: # return $online;
826: #}
827:
828: sub connected {
829: my ($local,$remote)=@_;
830: &status("Checking connection $local to $remote");
831: $local=~s/\W//g;
832: $remote=~s/\W//g;
833:
834: unless ($hostname{$local}) { return 'local_unknown'; }
835: unless ($hostname{$remote}) { return 'remote_unknown'; }
836:
837: #unless (&online($hostname{$local})) { return 'local_offline'; }
838:
839: my $ua=new LWP::UserAgent;
840:
841: my $request=new HTTP::Request('GET',
842: "http://".$hostname{$local}.'/cgi-bin/ping.pl?'.$remote);
843:
844: my $response=$ua->request($request);
845:
846: unless ($response->is_success) { return 'local_error'; }
847:
848: my $reply=$response->content;
849: $reply=(split("\n",$reply))[0];
850: $reply=~s/\W//g;
851: if ($reply ne $remote) { return $reply; }
852: return 'ok';
853: }
854:
855:
856:
857: sub hangup {
858: foreach (keys %children) {
859: $wasserver=$children{$_};
860: &status("Closing $wasserver");
861: &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
862: &status("Kill PID $_ for $wasserver");
863: kill ('INT',$_);
864: }
865: }
866:
867: sub HUNTSMAN { # signal handler for SIGINT
868: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
869: &hangup();
870: my $execdir=$perlvar{'lonDaemons'};
871: unlink("$execdir/logs/lonc.pid");
872: &logthis("<font color=red>CRITICAL: Shutting down</font>");
873: exit; # clean up with dignity
874: }
875:
876: sub HUPSMAN { # signal handler for SIGHUP
877: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
878: &hangup();
879: &logthis("<font color=red>CRITICAL: Restarting</font>");
880: unlink("$execdir/logs/lonc.pid");
881: my $execdir=$perlvar{'lonDaemons'};
882: exec("$execdir/lonc"); # here we go again
883: }
884:
885: sub checkchildren {
886: &initnewstatus();
887: &logstatus();
888: &logthis('Going to check on the children');
889: foreach (sort keys %children) {
890: sleep 1;
891: unless (kill 'USR1' => $_) {
892: &logthis ('<font color=red>CRITICAL: Child '.$_.' is dead</font>');
893: &logstatus($$.' is dead');
894: }
895: }
896: }
897:
898: sub USRMAN {
899: &logthis("USR1: Trying to establish connections again");
900: %childatt=();
901: &checkchildren();
902: }
903:
904: # -------------------------------------------------- Non-critical communication
905: sub subreply {
906: my ($cmd,$server)=@_;
907: my $answer='';
908: if ($server ne $perlvar{'lonHostID'}) {
909: my $peerfile="$perlvar{'lonSockDir'}/$server";
910: my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
911: Type => SOCK_STREAM,
912: Timeout => 10)
913: or return "con_lost";
914:
915:
916: $answer = londtransaction($sclient, $cmd, 10);
917:
918: if ((!$answer) || ($@=~/timeout/)) { $answer="con_lost"; }
919: $SIG{ALRM}='DEFAULT';
920: $SIG{__DIE__}=\&catchexception;
921: } else { $answer='self_reply'; }
922: return $answer;
923: }
924:
925: # --------------------------------------------------------------------- Logging
926:
927: sub logthis {
928: my $message=shift;
929: my $execdir=$perlvar{'lonDaemons'};
930: my $fh=IO::File->new(">>$execdir/logs/lonc.log");
931: my $now=time;
932: my $local=localtime($now);
933: $lastlog=$local.': '.$message;
934: print $fh "$local ($$) [$conserver] [$status]: $message\n";
935: }
936:
937: #-------------------------------------- londtransaction:
938: #
939: # Performs a transaction with lond with timeout support.
940: # result = londtransaction(socket,request,timeout)
941: #
942: sub londtransaction {
943: my ($socket, $request, $tmo) = @_;
944:
945: if($DEBUG) {
946: &logthis("londtransaction request: $request");
947: }
948:
949: # Set the signal handlers: ALRM for timeout and disble the others.
950:
951: $SIG{ALRM} = sub { die "timeout" };
952: $SIG{__DIE__} = 'DEFAULT';
953:
954: # Disable all but alarm so that only that can interupt the
955: # send /receive.
956: #
957: my $sigset = POSIX::SigSet->new(QUIT, USR1, HUP, INT, TERM);
958: my $priorsigs = POSIX::SigSet->new;
959: unless (defined sigprocmask(SIG_BLOCK, $sigset, $priorsigs)) {
960: &logthis("<font color=red> CRITICAL -- londtransaction ".
961: "failed to block signals </font>");
962: die "could not block signals in londtransaction";
963: }
964: $answer = '';
965: #
966: # Send request to lond.
967: #
968: eval {
969: alarm($tmo);
970: print $socket "$request\n";
971: alarm(0);
972: };
973: # If request didn't timeout, try for the response.
974: #
975:
976: if ($@!~/timeout/) {
977: eval {
978: alarm($tmo);
979: $answer = <$socket>;
980: if($DEBUG) {
981: &logthis("Received $answer in londtransaction");
982: }
983: alarm(0);
984: };
985: } else {
986: if($DEBUG) {
987: &logthis("Timeout on send in londtransaction");
988: }
989: }
990: if( ($@ =~ /timeout/) && ($DEBUG)) {
991: &logthis("Timeout on receive in londtransaction");
992: }
993: #
994: # Restore the initial sigmask set.
995: #
996: unless (defined sigprocmask(SIG_UNBLOCK, $priorsigs)) {
997: &logthis("<font color=red> CRITICAL -- londtransaction ".
998: "failed to re-enable signal processing. </font>");
999: die "londtransaction failed to re-enable signals";
1000: }
1001: #
1002: # go back to the prior handler set.
1003: #
1004: $SIG{ALRM} = 'DEFAULT';
1005: $SIG{__DIE__} = \&cathcexception;
1006:
1007: # chomp $answer;
1008: if ($DEBUG) {
1009: &logthis("Returning $answer in londtransaction");
1010: }
1011: return $answer;
1012:
1013: }
1014:
1015: sub logperm {
1016: my $message=shift;
1017: my $execdir=$perlvar{'lonDaemons'};
1018: my $now=time;
1019: my $local=localtime($now);
1020: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
1021: print $fh "$now:$message:$local\n";
1022: }
1023: # ------------------------------------------------------------------ Log status
1024:
1025: sub logstatus {
1026: my $docdir=$perlvar{'lonDocRoot'};
1027: my $fh=IO::File->new(">>$docdir/lon-status/loncstatus.txt");
1028: print $fh $$."\t".$conserver."\t".$status."\t".$lastlog."\n";
1029: }
1030:
1031: sub initnewstatus {
1032: my $docdir=$perlvar{'lonDocRoot'};
1033: my $fh=IO::File->new(">$docdir/lon-status/loncstatus.txt");
1034: my $now=time;
1035: my $local=localtime($now);
1036: print $fh "LONC status $local - parent $$\n\n";
1037: }
1038:
1039: # -------------------------------------------------------------- Status setting
1040:
1041: sub status {
1042: my $what=shift;
1043: my $now=time;
1044: my $local=localtime($now);
1045: $status=$local.': '.$what;
1046: }
1047:
1048:
1049:
1050: # ----------------------------------- POD (plain old documentation, CPAN style)
1051:
1052: =head1 NAME
1053:
1054: lonc - LON TCP-MySQL-Server Daemon for handling database requests.
1055:
1056: =head1 SYNOPSIS
1057:
1058: Usage: B<lonc>
1059:
1060: Should only be run as user=www. This is a command-line script which
1061: is invoked by B<loncron>. There is no expectation that a typical user
1062: will manually start B<lonc> from the command-line. (In other words,
1063: DO NOT START B<lonc> YOURSELF.)
1064:
1065: =head1 DESCRIPTION
1066:
1067: Provides persistent TCP connections to the other servers in the network
1068: through multiplexed domain sockets
1069:
1070: B<lonc> forks off children processes that correspond to the other servers
1071: in the network. Management of these processes can be done at the
1072: parent process level or the child process level.
1073:
1074: After forking off the children, B<lonc> the B<parent>
1075: executes a main loop which simply waits for processes to exit.
1076: As a process exits, a new process managing a link to the same
1077: peer as the exiting process is created.
1078:
1079: B<logs/lonc.log> is the location of log messages.
1080:
1081: The process management is now explained in terms of linux shell commands,
1082: subroutines internal to this code, and signal assignments:
1083:
1084: =over 4
1085:
1086: =item *
1087:
1088: PID is stored in B<logs/lonc.pid>
1089:
1090: This is the process id number of the parent B<lonc> process.
1091:
1092: =item *
1093:
1094: SIGTERM and SIGINT
1095:
1096: Parent signal assignment:
1097: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
1098:
1099: Child signal assignment:
1100: $SIG{INT} = 'DEFAULT'; (and SIGTERM is DEFAULT also)
1101: (The child dies and a SIGALRM is sent to parent, awaking parent from slumber
1102: to restart a new child.)
1103:
1104: Command-line invocations:
1105: B<kill> B<-s> SIGTERM I<PID>
1106: B<kill> B<-s> SIGINT I<PID>
1107:
1108: Subroutine B<HUNTSMAN>:
1109: This is only invoked for the B<lonc> parent I<PID>.
1110: This kills all the children, and then the parent.
1111: The B<lonc.pid> file is cleared.
1112:
1113: =item *
1114:
1115: SIGHUP
1116:
1117: Current bug:
1118: This signal can only be processed the first time
1119: on the parent process. Subsequent SIGHUP signals
1120: have no effect.
1121:
1122: Parent signal assignment:
1123: $SIG{HUP} = \&HUPSMAN;
1124:
1125: Child signal assignment:
1126: none (nothing happens)
1127:
1128: Command-line invocations:
1129: B<kill> B<-s> SIGHUP I<PID>
1130:
1131: Subroutine B<HUPSMAN>:
1132: This is only invoked for the B<lonc> parent I<PID>,
1133: This kills all the children, and then the parent.
1134: The B<lonc.pid> file is cleared.
1135:
1136: =item *
1137:
1138: SIGUSR1
1139:
1140: Parent signal assignment:
1141: $SIG{USR1} = \&USRMAN;
1142:
1143: Child signal assignment:
1144: $SIG{USR1}= \&logstatus;
1145:
1146: Command-line invocations:
1147: B<kill> B<-s> SIGUSR1 I<PID>
1148:
1149: Subroutine B<USRMAN>:
1150: When invoked for the B<lonc> parent I<PID>,
1151: SIGUSR1 is sent to all the children, and the status of
1152: each connection is logged.
1153:
1154:
1155: =back
1156:
1157: =head1 PREREQUISITES
1158:
1159: POSIX
1160: IO::Socket
1161: IO::Select
1162: IO::File
1163: Socket
1164: Fcntl
1165: Tie::RefHash
1166: Crypt::IDEA
1167:
1168: =head1 COREQUISITES
1169:
1170: =head1 OSNAMES
1171:
1172: linux
1173:
1174: =head1 SCRIPT CATEGORIES
1175:
1176: Server/Process
1177:
1178: =cut
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