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 1.39 2002/04/10 04:35:31 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: # or a signal (e.g. USR1 for restart).
180: # if a signal, the wait will fail
181: # This is ordinarily detected by
182: # checking for the existence of the
183: # pid index inthe children hash since
184: # the return value from a failed wait is -1
185: # which is an impossible PID.
186: &status("Woke up");
187: my $skipping='';
188:
189: if(exists($children{$deadpid})) {
190:
191: $thisserver = $children{$deadpid}; # Look name of dead guy's peer.
192:
193: delete($children{$deadpid}); # Get rid of dead hash entry.
194:
195: if($childatt{$thisserver} < $childmaxattempts) {
196: $childatt{$thisserver}++;
197: &logthis(
198: "<font color=yellow>INFO: Trying to reconnect for $thisserver "
199: ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
200: make_new_child($thisserver);
201:
202: }
203: else {
204: $skipping .= $thisserver.' ';
205: }
206: if($skipping) {
207: &logthis("<font color=blue>WARNING: Skipped $skipping</font>");
208:
209: }
210: }
211:
212: }
213:
214:
215:
216: sub make_new_child {
217:
218: $newserver=shift;
219: my $pid;
220: my $sigset;
221: &logthis("Attempting to start child for server $newserver");
222: # block signal for fork
223: $sigset = POSIX::SigSet->new(SIGINT);
224: sigprocmask(SIG_BLOCK, $sigset)
225: or die "Can't block SIGINT for fork: $!\n";
226:
227: die "fork: $!" unless defined ($pid = fork);
228:
229: if ($pid) {
230: # Parent records the child's birth and returns.
231: sigprocmask(SIG_UNBLOCK, $sigset)
232: or die "Can't unblock SIGINT for fork: $!\n";
233: $children{$pid} = $newserver;
234: $childpid{$newserver} = $pid;
235: return;
236: } else {
237: $conserver=$newserver;
238: # Child can *not* return from this subroutine.
239: $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
240: $SIG{USR1}= \&logstatus;
241:
242: # unblock signals
243: sigprocmask(SIG_UNBLOCK, $sigset)
244: or die "Can't unblock SIGINT for fork: $!\n";
245:
246: # ----------------------------- This is the modified main program of non-forker
247:
248: $port = "$perlvar{'lonSockDir'}/$conserver";
249:
250: unlink($port);
251:
252: # -------------------------------------------------------------- Open other end
253:
254: &openremote($conserver);
255: &logthis("<font color=green> Connection to $conserver open </font>");
256: # ----------------------------------------- We're online, send delayed messages
257: &status("Checking for delayed messages");
258:
259: my @allbuffered;
260: my $path="$perlvar{'lonSockDir'}/delayed";
261: opendir(DIRHANDLE,$path);
262: @allbuffered=grep /\.$conserver$/, readdir DIRHANDLE;
263: closedir(DIRHANDLE);
264: my $dfname;
265: foreach (@allbuffered) {
266: &status("Sending delayed: $_");
267: $dfname="$path/$_";
268: if($DEBUG) { &logthis('Sending '.$dfname); }
269: my $wcmd;
270: {
271: my $dfh=IO::File->new($dfname);
272: $cmd=<$dfh>;
273: }
274: chomp($cmd);
275: my $bcmd=$cmd;
276: if ($cmd =~ /^encrypt\:/) {
277: my $rcmd=$cmd;
278: $rcmd =~ s/^encrypt\://;
279: chomp($rcmd);
280: my $cmdlength=length($rcmd);
281: $rcmd.=" ";
282: my $encrequest='';
283: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
284: $encrequest.=
285: unpack("H16",$cipher->encrypt(substr($rcmd,$encidx,8)));
286: }
287: $cmd="enc:$cmdlength:$encrequest\n";
288: }
289: $answer = londtransaction($remotesock, $cmd, 60);
290: chomp($answer);
291:
292: if (($answer ne '') && ($@!~/timeout/)) {
293: unlink("$dfname");
294: &logthis("Delayed $cmd: >$answer<");
295: &logperm("S:$conserver:$bcmd");
296: }
297: }
298: if($DEBUG) { &logthis("<font color=green> Delayed transactions sent"); }
299:
300: # ------------------------------------------------------- Listen to UNIX socket
301: &status("Opening socket");
302: unless (
303: $server = IO::Socket::UNIX->new(Local => $port,
304: Type => SOCK_STREAM,
305: Listen => 10 )
306: ) {
307: my $st=120+int(rand(240));
308: &logthis(
309: "<font color=blue>WARNING: ".
310: "Can't make server socket ($st secs): .. exiting</font>");
311: sleep($st);
312: exit;
313: };
314:
315: # -----------------------------------------------------------------------------
316:
317: &logthis("<font color=green>$conserver online</font>");
318:
319: # -----------------------------------------------------------------------------
320: # begin with empty buffers
321: %inbuffer = ();
322: %outbuffer = ();
323: %ready = ();
324: %servers = (); # To be compatible with make filevector. indexed by
325: # File ids, values are sockets.
326: # note that the accept socket is omitted.
327:
328: tie %ready, 'Tie::RefHash';
329:
330: # nonblock($server);
331: # $select = IO::Select->new($server);
332:
333: # Main loop: check reads/accepts, check writes, check ready to process
334:
335: status("Main loop");
336: while (1) {
337: my $client;
338: my $rv;
339: my $data;
340:
341: my $infdset; # bit vec of fd's to select on input.
342:
343: my $outfdset; # Bit vec of fd's to select on output.
344:
345:
346: $infdset = MakeFileVector(\%servers);
347: $outfdset= MakeFileVector(\%outbuffer);
348: vec($infdset, $server->fileno, 1) = 1;
349: if($DEBUG) {
350: &logthis("Adding ".$server->fileno.
351: " to input select vector (listner)".
352: unpack("b*",$infdset)."\n");
353: }
354: DoSelect(\$infdset, \$outfdset); # Wait for input.
355: if($DEBUG) {
356: &logthis("Doselect completed!");
357: &logthis("ins = ".unpack("b*",$infdset)."\n");
358: &logthis("outs= ".unpack("b*",$outfdset)."\n");
359:
360: }
361:
362: # Checkfor new connections:
363: if (vec($infdset, $server->fileno, 1)) {
364: if($DEBUG) {
365: &logthis("New connection established");
366: }
367: # accept a new connection
368: &status("Accept new connection: $conserver");
369: $client = $server->accept();
370: if($DEBUG) {
371: &logthis("New client fd = ".$client->fileno."\n");
372: }
373: $servers{$client->fileno} = $client;
374: nonblock($client);
375: }
376: HandleInput($infdset, \%servers, \%inbuffer, \%outbuffer, \%ready);
377: HandleOutput($outfdset, \%servers, \%outbuffer, \%inbuffer,
378: \%ready);
379: # -------------------------------------------------------- Wow, connection lost
380:
381: }
382:
383: }
384: }
385:
386: # ------------------------------------------------------- End of make_new_child
387:
388:
389: #
390: # Make a vector of file descriptors to wait for in a select.
391: # parameters:
392: # \%fdhash -reference to a hash which has IO::Socket's as indices.
393: # We only care about the indices, not the values.
394: # A select vector is created from all indices of the hash.
395:
396: sub MakeFileVector
397: {
398: my $fdhash = shift;
399: my $selvar = "";
400:
401: foreach $socket (keys %$fdhash) {
402: if($DEBUG) {
403: &logthis("Adding ".$socket.
404: "to select vector. (client)\n");
405: }
406: vec($selvar, $socket, 1) = 1;
407: }
408: return $selvar;
409: }
410:
411:
412: #
413: # HandleOutput:
414: # Processes output on a buffered set of file descriptors which are
415: # ready to be read.
416: # Parameters:
417: # $selvector - Vector of file descriptors which are writable.
418: # \%sockets - Vector of socket references indexed by socket.
419: # \%buffers - Reference to a hash containing output buffers.
420: # Hashes are indexed by sockets. The file descriptors of some
421: # of those sockets will be present in $selvector.
422: # For each one of those, we will attempt to write the output
423: # buffer to the socket. Note that we will assume that
424: # the sockets are being run in non blocking mode.
425: # \%inbufs - Reference to hash containing input buffers.
426: # \%readys - Reference to hash containing flags for items with complete
427: # requests.
428: #
429: sub HandleOutput
430: {
431: my $selvector = shift;
432: my $sockets = shift;
433: my $buffers = shift;
434: my $inbufs = shift;
435: my $readys = shift;
436: my $sock;
437:
438: if($DEBUG) {
439: &logthis("HandleOutput entered\n");
440: }
441:
442: foreach $sock (keys %$sockets) {
443: my $socket = $sockets->{$sock};
444: if(vec($selvector, $sock, 1)) { # $socket is writable.
445: if($DEBUG) {
446: &logthis("Sending $buffers->{$sock} \n");
447: }
448: my $rv = $socket->send($buffers->{$sock}, 0);
449: $errno = $!;
450: unless ($buffers->{$sock} eq "con_lost\n") {
451: unless (defined $rv) { # Write failed... could be EINTR
452: unless ($errno == POSIX::EINTR) {
453: &logthis("Write failed on writable socket");
454: } # EINTR is not an error .. just retry.
455: next;
456: }
457: if( ($rv == length $buffers->{$sock}) ||
458: ($errno == POSIX::EWOULDBLOCK) ||
459: ($errno == POSIX::EAGAIN) || # same as above.
460: ($errno == POSIX::EINTR) || # signal during IO
461: ($errno == 0)) {
462: substr($buffers->{$sock}, 0, $rv)=""; # delete written part
463: delete $buffers->{$sock} unless length $buffers->{$sock};
464: } else {
465: # For some reason the write failed with an error code
466: # we didn't look for. Shutdown the socket.
467: &logthis("Unable to write data with ".$errno.": ".
468: "Dropping data: ".length($buffers->{$sock}).
469: ", $rv");
470: #
471: # kill off the buffers in the hash:
472:
473: delete $buffers->{$sock};
474: delete $inbufs->{$sock};
475: delete $readys->{$sock};
476:
477: close($socket); # Close the client socket.
478: next;
479: }
480: } else { # Kludgy way to mark lond connection lost.
481: &logthis(
482: "<font color=red>CRITICAL lond connection lost</font>");
483: status("Connection lost");
484: $remotesock->shutdown(2);
485: &logthis("Attempting to open a new connection");
486: &openremote($conserver);
487: }
488:
489: }
490: }
491:
492: }
493: #
494: # HandleInput - Deals with input on client sockets.
495: # Each socket has an associated input buffer.
496: # For each readable socket, the currently available
497: # data is appended to this buffer.
498: # If necessary, the buffer is created.
499: # On various failures, we may shutdown the client.
500: # Parameters:
501: # $selvec - Vector of readable sockets.
502: # \%sockets - Refers to the Hash of sockets indexed by sockets.
503: # Each of these may or may not have it's fd bit set
504: # in the $selvec.
505: # \%ibufs - Refers to the hash of input buffers indexed by socket.
506: # \%obufs - Hash of output buffers indexed by socket.
507: # \%ready - Hash of ready flags indicating the existence of a completed
508: # Request.
509: sub HandleInput
510: {
511:
512: # Marshall the parameters. Note that the hashes are actually
513: # references not values.
514:
515: my $selvec = shift;
516: my $sockets = shift;
517: my $ibufs = shift;
518: my $obufs = shift;
519: my $ready = shift;
520: my $sock;
521:
522: if($DEBUG) {
523: &logthis("Entered HandleInput\n");
524: }
525: foreach $sock (keys %$sockets) {
526: my $socket = $sockets->{$sock};
527: if(vec($selvec, $sock, 1)) { # Socket which is readable.
528:
529: # Attempt to read the data and do error management.
530: my $data = '';
531: my $rv = $socket->recv($data, POSIX::BUFSIZ, 0);
532: if($DEBUG) {
533: &logthis("Received $data from socket");
534: }
535: unless (defined($rv) && length $data) {
536:
537: # Read an end of file.. this is a disconnect from the peer.
538:
539: delete $sockets->{$sock};
540: delete $ibufs->{$sock};
541: delete $obufs->{$sock};
542: delete $ready->{$sock};
543:
544: status("Idle");
545: close $socket;
546: next;
547: }
548: # Append the read data to the input buffer. If the buffer
549: # now contains a \n the request is complete and we can
550: # mark this in the $ready hash (one request for each \n.)
551:
552: $ibufs->{$sock} .= $data;
553: while($ibufs->{$sock} =~ s/(.*\n)//) {
554: push(@{$ready->{$sock}}, $1);
555: }
556:
557: }
558: }
559: # Now handle any requests which are ready:
560:
561: foreach $client (keys %ready) {
562: handle($client);
563: }
564: }
565:
566: # DoSelect: does a select with no timeout. On signal (errno == EINTR),
567: # the select is retried until there are items in the returned
568: # vectors.
569: #
570: # Parameters:
571: # \$readvec - Reference to a vector of file descriptors to
572: # check for readability.
573: # \$writevec - Reference to a vector of file descriptors to check for
574: # writability.
575: # On exit, the referents are modified with vectors indicating which
576: # file handles are readable/writable.
577: #
578: sub DoSelect {
579: my $readvec = shift;
580: my $writevec= shift;
581: my $outs;
582: my $ins;
583:
584: while (1) {
585: my $nfds = select( $ins = $$readvec, $outs = $$writevec, undef, undef);
586: if($nfds) {
587: if($DEBUG) {
588: &logthis("select exited with ".$nfds." fds\n");
589: &logthis("ins = ".unpack("b*",$ins).
590: " readvec = ".unpack("b*",$$readvec)."\n");
591: &logthis("outs = ".unpack("b*",$outs).
592: " writevec = ".unpack("b*",$$writevec)."\n");
593: }
594: $$readvec = $ins;
595: $$writevec = $outs;
596: return;
597: } else {
598: if($DEBUG) {
599: &logthis("Select exited with no bits set in mask\n");
600: }
601: die "Select failed" unless $! == EINTR;
602: }
603: }
604: }
605:
606: # handle($socket) deals with all pending requests for $client
607: #
608: sub handle {
609: # requests are in $ready{$client}
610: # send output to $outbuffer{$client}
611: my $client = shift;
612: my $request;
613: foreach $request (@{$ready{$client}}) {
614: # ============================================================= Process request
615: # $request is the text of the request
616: # put text of reply into $outbuffer{$client}
617: # ------------------------------------------------------------ Is this the end?
618: chomp($request);
619: if($DEBUG) {
620: &logthis("<font color=green> Request $request processing starts</font>");
621: }
622: if ($request eq "close_connection_exit\n") {
623: &status("Request close connection");
624: &logthis(
625: "<font color=red>CRITICAL: Request Close Connection ... exiting</font>");
626: $remotesock->shutdown(2);
627: $server->close();
628: exit;
629: }
630: # -----------------------------------------------------------------------------
631: if ($request =~ /^encrypt\:/) {
632: my $cmd=$request;
633: $cmd =~ s/^encrypt\://;
634: chomp($cmd);
635: my $cmdlength=length($cmd);
636: $cmd.=" ";
637: my $encrequest='';
638: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
639: $encrequest.=
640: unpack("H16",$cipher->encrypt(substr($cmd,$encidx,8)));
641: }
642: $request="enc:$cmdlength:$encrequest";
643: }
644: # --------------------------------------------------------------- Main exchange
645: $answer = londtransaction($remotesock, $request, 300);
646:
647: if($DEBUG) {
648: &logthis("<font color=green> Request data exchange complete");
649: }
650: if ($@=~/timeout/) {
651: $answer='';
652: &logthis(
653: "<font color=red>CRITICAL: Timeout: $request</font>");
654: }
655:
656:
657: if ($answer) {
658: if ($answer =~ /^enc/) {
659: my ($cmd,$cmdlength,$encinput)=split(/:/,$answer);
660: chomp($encinput);
661: $answer='';
662: for (my $encidx=0;$encidx<length($encinput);$encidx+=16) {
663: $answer.=$cipher->decrypt(
664: pack("H16",substr($encinput,$encidx,16))
665: );
666: }
667: $answer=substr($answer,0,$cmdlength);
668: $answer.="\n";
669: }
670: if($DEBUG) {
671: &logthis("sending $answer to client\n");
672: }
673: $outbuffer{$client} .= $answer;
674: } else {
675: $outbuffer{$client} .= "con_lost\n";
676: }
677:
678: &status("Completed: $request");
679: if($DEBUG) {
680: &logthis("<font color=green> Request processing complete</font>");
681: }
682: # ===================================================== Done processing request
683: }
684: delete $ready{$client};
685: # -------------------------------------------------------------- End non-forker
686: if($DEBUG) {
687: &logthis("<font color=green> requests for child handled</font>");
688: }
689: }
690: # ---------------------------------------------------------- End make_new_child
691:
692: # nonblock($socket) puts socket into nonblocking mode
693: sub nonblock {
694: my $socket = shift;
695: my $flags;
696:
697:
698: $flags = fcntl($socket, F_GETFL, 0)
699: or die "Can't get flags for socket: $!\n";
700: fcntl($socket, F_SETFL, $flags | O_NONBLOCK)
701: or die "Can't make socket nonblocking: $!\n";
702: }
703:
704:
705: sub openremote {
706: # ---------------------------------------------------- Client to network server
707:
708: my $conserver=shift;
709:
710: &status("Opening TCP");
711: my $st=120+int(rand(240)); # Sleep before opening:
712:
713: unless (
714: $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
715: PeerPort => $perlvar{'londPort'},
716: Proto => "tcp",
717: Type => SOCK_STREAM)
718: ) {
719:
720: &logthis(
721: "<font color=blue>WARNING: Couldn't connect to $conserver ($st secs): </font>");
722: sleep($st);
723: exit;
724: };
725: # ----------------------------------------------------------------- Init dialog
726:
727: &logthis("<font color=green>INFO Connected to $conserver, initing </font>");
728: &status("Init dialogue: $conserver");
729:
730: $answer = londtransaction($remotesock, "init", 60);
731: chomp($answer);
732: $answer = londtransaction($remotesock, $answer, 60);
733: chomp($answer);
734:
735: if ($@=~/timeout/) {
736: &logthis("Timed out during init.. exiting");
737: exit;
738: }
739:
740: if ($answer ne 'ok') {
741: &logthis("Init reply: >$answer<");
742: my $st=120+int(rand(240));
743: &logthis(
744: "<font color=blue>WARNING: Init failed ($st secs)</font>");
745: sleep($st);
746: exit;
747: }
748:
749: sleep 5;
750: &status("Ponging");
751: print $remotesock "pong\n";
752: $answer=<$remotesock>;
753: chomp($answer);
754: if ($answer!~/^$conserver/) {
755: &logthis("Pong reply: >$answer<");
756: }
757: # ----------------------------------------------------------- Initialize cipher
758:
759: &status("Initialize cipher");
760: print $remotesock "ekey\n";
761: my $buildkey=<$remotesock>;
762: my $key=$conserver.$perlvar{'lonHostID'};
763: $key=~tr/a-z/A-Z/;
764: $key=~tr/G-P/0-9/;
765: $key=~tr/Q-Z/0-9/;
766: $key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
767: $key=substr($key,0,32);
768: my $cipherkey=pack("H32",$key);
769: if ($cipher=new IDEA $cipherkey) {
770: &logthis("Secure connection initialized");
771: } else {
772: my $st=120+int(rand(240));
773: &logthis(
774: "<font color=blue>WARNING: ".
775: "Could not establish secure connection ($st secs)!</font>");
776: sleep($st);
777: exit;
778: }
779: &logthis("<font color=green> Remote open success </font>");
780: }
781:
782:
783:
784: # grabs exception and records it to log before exiting
785: sub catchexception {
786: my ($signal)=@_;
787: $SIG{QUIT}='DEFAULT';
788: $SIG{__DIE__}='DEFAULT';
789: chomp($signal);
790: &logthis("<font color=red>CRITICAL: "
791: ."ABNORMAL EXIT. Child $$ for server [$wasserver] died through "
792: ."\"$signal\" with parameter </font>");
793: die("Signal abend");
794: }
795:
796: # -------------------------------------- Routines to see if other box available
797:
798: #sub online {
799: # my $host=shift;
800: # &status("Pinging ".$host);
801: # my $p=Net::Ping->new("tcp",20);
802: # my $online=$p->ping("$host");
803: # $p->close();
804: # undef ($p);
805: # return $online;
806: #}
807:
808: sub connected {
809: my ($local,$remote)=@_;
810: &status("Checking connection $local to $remote");
811: $local=~s/\W//g;
812: $remote=~s/\W//g;
813:
814: unless ($hostname{$local}) { return 'local_unknown'; }
815: unless ($hostname{$remote}) { return 'remote_unknown'; }
816:
817: #unless (&online($hostname{$local})) { return 'local_offline'; }
818:
819: my $ua=new LWP::UserAgent;
820:
821: my $request=new HTTP::Request('GET',
822: "http://".$hostname{$local}.'/cgi-bin/ping.pl?'.$remote);
823:
824: my $response=$ua->request($request);
825:
826: unless ($response->is_success) { return 'local_error'; }
827:
828: my $reply=$response->content;
829: $reply=(split("\n",$reply))[0];
830: $reply=~s/\W//g;
831: if ($reply ne $remote) { return $reply; }
832: return 'ok';
833: }
834:
835:
836:
837: sub hangup {
838: foreach (keys %children) {
839: $wasserver=$children{$_};
840: &status("Closing $wasserver");
841: &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
842: &status("Kill PID $_ for $wasserver");
843: kill ('INT',$_);
844: }
845: }
846:
847: sub HUNTSMAN { # signal handler for SIGINT
848: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
849: &hangup();
850: my $execdir=$perlvar{'lonDaemons'};
851: unlink("$execdir/logs/lonc.pid");
852: &logthis("<font color=red>CRITICAL: Shutting down</font>");
853: exit; # clean up with dignity
854: }
855:
856: sub HUPSMAN { # signal handler for SIGHUP
857: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
858: &hangup();
859: &logthis("<font color=red>CRITICAL: Restarting</font>");
860: unlink("$execdir/logs/lonc.pid");
861: my $execdir=$perlvar{'lonDaemons'};
862: exec("$execdir/lonc"); # here we go again
863: }
864:
865: sub checkchildren {
866: &initnewstatus();
867: &logstatus();
868: &logthis('Going to check on the children');
869: foreach (sort keys %children) {
870: sleep 1;
871: unless (kill 'USR1' => $_) {
872: &logthis ('<font color=red>CRITICAL: Child '.$_.' is dead</font>');
873: &logstatus($$.' is dead');
874: }
875: }
876: }
877:
878: sub USRMAN {
879: &logthis("USR1: Trying to establish connections again");
880: #
881: # It is really important not to just clear the childatt hash or we will
882: # lose all memory of the children. What we really want to do is this:
883: # For each index where childatt is >= $childmaxattempts
884: # Zero the associated counter and do a make_child for the host.
885: # Regardles, the childatt entry is zeroed:
886: my $host;
887: foreach $host (keys %childatt) {
888: if ($childatt{$host} >= $childmaxattempts) {
889: $childatt{$host} = 0;
890: &logthis("<font color=green>INFO: Restarting child for server: "
891: .$host."</font>\n");
892: make_new_child($host);
893: }
894: else {
895: $childatt{$host} = 0;
896: }
897: }
898: &checkchildren(); # See if any children are still dead...
899: }
900:
901: # -------------------------------------------------- Non-critical communication
902: sub subreply {
903: my ($cmd,$server)=@_;
904: my $answer='';
905: if ($server ne $perlvar{'lonHostID'}) {
906: my $peerfile="$perlvar{'lonSockDir'}/$server";
907: my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
908: Type => SOCK_STREAM,
909: Timeout => 10)
910: or return "con_lost";
911:
912:
913: $answer = londtransaction($sclient, $cmd, 10);
914:
915: if ((!$answer) || ($@=~/timeout/)) { $answer="con_lost"; }
916: $SIG{ALRM}='DEFAULT';
917: $SIG{__DIE__}=\&catchexception;
918: } else { $answer='self_reply'; }
919: return $answer;
920: }
921:
922: # --------------------------------------------------------------------- Logging
923:
924: sub logthis {
925: my $message=shift;
926: my $execdir=$perlvar{'lonDaemons'};
927: my $fh=IO::File->new(">>$execdir/logs/lonc.log");
928: my $now=time;
929: my $local=localtime($now);
930: $lastlog=$local.': '.$message;
931: print $fh "$local ($$) [$conserver] [$status]: $message\n";
932: }
933:
934: #-------------------------------------- londtransaction:
935: #
936: # Performs a transaction with lond with timeout support.
937: # result = londtransaction(socket,request,timeout)
938: #
939: sub londtransaction {
940: my ($socket, $request, $tmo) = @_;
941:
942: if($DEBUG) {
943: &logthis("londtransaction request: $request");
944: }
945:
946: # Set the signal handlers: ALRM for timeout and disble the others.
947:
948: $SIG{ALRM} = sub { die "timeout" };
949: $SIG{__DIE__} = 'DEFAULT';
950:
951: # Disable all but alarm so that only that can interupt the
952: # send /receive.
953: #
954: my $sigset = POSIX::SigSet->new(QUIT, USR1, HUP, INT, TERM);
955: my $priorsigs = POSIX::SigSet->new;
956: unless (defined sigprocmask(SIG_BLOCK, $sigset, $priorsigs)) {
957: &logthis("<font color=red> CRITICAL -- londtransaction ".
958: "failed to block signals </font>");
959: die "could not block signals in londtransaction";
960: }
961: $answer = '';
962: #
963: # Send request to lond.
964: #
965: eval {
966: alarm($tmo);
967: print $socket "$request\n";
968: alarm(0);
969: };
970: # If request didn't timeout, try for the response.
971: #
972:
973: if ($@!~/timeout/) {
974: eval {
975: alarm($tmo);
976: $answer = <$socket>;
977: if($DEBUG) {
978: &logthis("Received $answer in londtransaction");
979: }
980: alarm(0);
981: };
982: } else {
983: if($DEBUG) {
984: &logthis("Timeout on send in londtransaction");
985: }
986: }
987: if( ($@ =~ /timeout/) && ($DEBUG)) {
988: &logthis("Timeout on receive in londtransaction");
989: }
990: #
991: # Restore the initial sigmask set.
992: #
993: unless (defined sigprocmask(SIG_UNBLOCK, $priorsigs)) {
994: &logthis("<font color=red> CRITICAL -- londtransaction ".
995: "failed to re-enable signal processing. </font>");
996: die "londtransaction failed to re-enable signals";
997: }
998: #
999: # go back to the prior handler set.
1000: #
1001: $SIG{ALRM} = 'DEFAULT';
1002: $SIG{__DIE__} = \&cathcexception;
1003:
1004: # chomp $answer;
1005: if ($DEBUG) {
1006: &logthis("Returning $answer in londtransaction");
1007: }
1008: return $answer;
1009:
1010: }
1011:
1012: sub logperm {
1013: my $message=shift;
1014: my $execdir=$perlvar{'lonDaemons'};
1015: my $now=time;
1016: my $local=localtime($now);
1017: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
1018: print $fh "$now:$message:$local\n";
1019: }
1020: # ------------------------------------------------------------------ Log status
1021:
1022: sub logstatus {
1023: my $docdir=$perlvar{'lonDocRoot'};
1024: my $fh=IO::File->new(">>$docdir/lon-status/loncstatus.txt");
1025: print $fh $$."\t".$conserver."\t".$status."\t".$lastlog."\n";
1026: }
1027:
1028: sub initnewstatus {
1029: my $docdir=$perlvar{'lonDocRoot'};
1030: my $fh=IO::File->new(">$docdir/lon-status/loncstatus.txt");
1031: my $now=time;
1032: my $local=localtime($now);
1033: print $fh "LONC status $local - parent $$\n\n";
1034: }
1035:
1036: # -------------------------------------------------------------- Status setting
1037:
1038: sub status {
1039: my $what=shift;
1040: my $now=time;
1041: my $local=localtime($now);
1042: $status=$local.': '.$what;
1043: }
1044:
1045:
1046:
1047: # ----------------------------------- POD (plain old documentation, CPAN style)
1048:
1049: =head1 NAME
1050:
1051: lonc - LON TCP-MySQL-Server Daemon for handling database requests.
1052:
1053: =head1 SYNOPSIS
1054:
1055: Usage: B<lonc>
1056:
1057: Should only be run as user=www. This is a command-line script which
1058: is invoked by B<loncron>. There is no expectation that a typical user
1059: will manually start B<lonc> from the command-line. (In other words,
1060: DO NOT START B<lonc> YOURSELF.)
1061:
1062: =head1 DESCRIPTION
1063:
1064: Provides persistent TCP connections to the other servers in the network
1065: through multiplexed domain sockets
1066:
1067: B<lonc> forks off children processes that correspond to the other servers
1068: in the network. Management of these processes can be done at the
1069: parent process level or the child process level.
1070:
1071: After forking off the children, B<lonc> the B<parent>
1072: executes a main loop which simply waits for processes to exit.
1073: As a process exits, a new process managing a link to the same
1074: peer as the exiting process is created.
1075:
1076: B<logs/lonc.log> is the location of log messages.
1077:
1078: The process management is now explained in terms of linux shell commands,
1079: subroutines internal to this code, and signal assignments:
1080:
1081: =over 4
1082:
1083: =item *
1084:
1085: PID is stored in B<logs/lonc.pid>
1086:
1087: This is the process id number of the parent B<lonc> process.
1088:
1089: =item *
1090:
1091: SIGTERM and SIGINT
1092:
1093: Parent signal assignment:
1094: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
1095:
1096: Child signal assignment:
1097: $SIG{INT} = 'DEFAULT'; (and SIGTERM is DEFAULT also)
1098: (The child dies and a SIGALRM is sent to parent, awaking parent from slumber
1099: to restart a new child.)
1100:
1101: Command-line invocations:
1102: B<kill> B<-s> SIGTERM I<PID>
1103: B<kill> B<-s> SIGINT I<PID>
1104:
1105: Subroutine B<HUNTSMAN>:
1106: This is only invoked for the B<lonc> parent I<PID>.
1107: This kills all the children, and then the parent.
1108: The B<lonc.pid> file is cleared.
1109:
1110: =item *
1111:
1112: SIGHUP
1113:
1114: Current bug:
1115: This signal can only be processed the first time
1116: on the parent process. Subsequent SIGHUP signals
1117: have no effect.
1118:
1119: Parent signal assignment:
1120: $SIG{HUP} = \&HUPSMAN;
1121:
1122: Child signal assignment:
1123: none (nothing happens)
1124:
1125: Command-line invocations:
1126: B<kill> B<-s> SIGHUP I<PID>
1127:
1128: Subroutine B<HUPSMAN>:
1129: This is only invoked for the B<lonc> parent I<PID>,
1130: This kills all the children, and then the parent.
1131: The B<lonc.pid> file is cleared.
1132:
1133: =item *
1134:
1135: SIGUSR1
1136:
1137: Parent signal assignment:
1138: $SIG{USR1} = \&USRMAN;
1139:
1140: Child signal assignment:
1141: $SIG{USR1}= \&logstatus;
1142:
1143: Command-line invocations:
1144: B<kill> B<-s> SIGUSR1 I<PID>
1145:
1146: Subroutine B<USRMAN>:
1147: When invoked for the B<lonc> parent I<PID>,
1148: SIGUSR1 is sent to all the children, and the status of
1149: each connection is logged.
1150:
1151:
1152: =back
1153:
1154: =head1 PREREQUISITES
1155:
1156: POSIX
1157: IO::Socket
1158: IO::Select
1159: IO::File
1160: Socket
1161: Fcntl
1162: Tie::RefHash
1163: Crypt::IDEA
1164:
1165: =head1 COREQUISITES
1166:
1167: =head1 OSNAMES
1168:
1169: linux
1170:
1171: =head1 SCRIPT CATEGORIES
1172:
1173: Server/Process
1174:
1175: =cut
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