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 1.26 2002/02/19 21:12:22 www 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
48: #
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: my $status='';
64: my $lastlog='';
65:
66: # grabs exception and records it to log before exiting
67: sub catchexception {
68: my ($signal)=@_;
69: $SIG{'QUIT'}='DEFAULT';
70: $SIG{__DIE__}='DEFAULT';
71: &logthis("<font color=red>CRITICAL: "
72: ."ABNORMAL EXIT. Child $$ for server $wasserver died through "
73: ."\"$signal\" with this parameter->[$@]</font>");
74: die($@);
75: }
76:
77: $childmaxattempts=5;
78:
79: # -------------------------------------- Routines to see if other box available
80:
81: sub online {
82: my $host=shift;
83: my $p=Net::Ping->new("tcp",10);
84: my $online=$p->ping("$host");
85: $p->close();
86: undef ($p);
87: return $online;
88: }
89:
90: sub connected {
91: my ($local,$remote)=@_;
92: $local=~s/\W//g;
93: $remote=~s/\W//g;
94:
95: unless ($hostname{$local}) { return 'local_unknown'; }
96: unless ($hostname{$remote}) { return 'remote_unknown'; }
97:
98: unless (&online($hostname{$local})) { return 'local_offline'; }
99:
100: my $ua=new LWP::UserAgent;
101:
102: my $request=new HTTP::Request('GET',
103: "http://".$hostname{$local}.'/cgi-bin/ping.pl?'.$remote);
104:
105: my $response=$ua->request($request);
106:
107: unless ($response->is_success) { return 'local_error'; }
108:
109: my $reply=$response->content;
110: $reply=(split("\n",$reply))[0];
111: $reply=~s/\W//g;
112: if ($reply ne $remote) { return $reply; }
113: return 'ok';
114: }
115:
116:
117: # -------------------------------- Set signal handlers to record abnormal exits
118:
119: $SIG{QUIT}=\&catchexception;
120: $SIG{__DIE__}=\&catchexception;
121:
122: # ------------------------------------ Read httpd access.conf and get variables
123:
124: open (CONFIG,"/etc/httpd/conf/access.conf") || die "Can't read access.conf";
125:
126: while ($configline=<CONFIG>) {
127: if ($configline =~ /PerlSetVar/) {
128: my ($dummy,$varname,$varvalue)=split(/\s+/,$configline);
129: chomp($varvalue);
130: $perlvar{$varname}=$varvalue;
131: }
132: }
133: close(CONFIG);
134:
135: # ----------------------------- Make sure this process is running from user=www
136: my $wwwid=getpwnam('www');
137: if ($wwwid!=$<) {
138: $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
139: $subj="LON: $perlvar{'lonHostID'} User ID mismatch";
140: system("echo 'User ID mismatch. lonc must be run as user www.' |\
141: mailto $emailto -s '$subj' > /dev/null");
142: exit 1;
143: }
144:
145: # --------------------------------------------- Check if other instance running
146:
147: my $pidfile="$perlvar{'lonDaemons'}/logs/lonc.pid";
148:
149: if (-e $pidfile) {
150: my $lfh=IO::File->new("$pidfile");
151: my $pide=<$lfh>;
152: chomp($pide);
153: if (kill 0 => $pide) { die "already running"; }
154: }
155:
156: # ------------------------------------------------------------- Read hosts file
157:
158: open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
159:
160: while ($configline=<CONFIG>) {
161: my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
162: chomp($ip);
163: $hostip{$id}=$ip;
164: }
165: close(CONFIG);
166:
167: # -------------------------------------------------------- Routines for forking
168:
169: %children = (); # keys are current child process IDs,
170: # values are hosts
171: %childpid = (); # the other way around
172:
173: %childatt = (); # number of attempts to start server
174: # for ID
175:
176: sub REAPER { # takes care of dead children
177: $SIG{CHLD} = \&REAPER;
178: my $pid = wait;
179: my $wasserver=$children{$pid};
180: &logthis("<font color=red>CRITICAL: "
181: ."Child $pid for server $wasserver died ($childatt{$wasserver})</font>");
182: delete $children{$pid};
183: delete $childpid{$wasserver};
184: my $port = "$perlvar{'lonSockDir'}/$wasserver";
185: unlink($port);
186: }
187:
188: sub HUNTSMAN { # signal handler for SIGINT
189: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
190: foreach (keys %children) {
191: $wasserver=$children{$_};
192: &status("Closing $wasserver");
193: &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
194: &status("Kill PID $_ for $wasserver");
195: kill ('INT',$_);
196: }
197: my $execdir=$perlvar{'lonDaemons'};
198: unlink("$execdir/logs/lonc.pid");
199: &logthis("<font color=red>CRITICAL: Shutting down</font>");
200: exit; # clean up with dignity
201: }
202:
203: sub HUPSMAN { # signal handler for SIGHUP
204: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
205: foreach (keys %children) {
206: $wasserver=$children{$_};
207: &status("Closing $wasserver");
208: &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
209: &status("Kill PID $_ for $wasserver");
210: kill ('INT',$_);
211: }
212: &logthis("<font color=red>CRITICAL: Restarting</font>");
213: unlink("$execdir/logs/lonc.pid");
214: my $execdir=$perlvar{'lonDaemons'};
215: exec("$execdir/lonc"); # here we go again
216: }
217:
218: sub checkchildren {
219: &initnewstatus();
220: &logstatus();
221: &logthis('Going to check on the children');
222: foreach (sort keys %children) {
223: sleep 1;
224: unless (kill 'USR1' => $_) {
225: &logthis ('Child '.$_.' is dead');
226: &logstatus($$.' is dead');
227: }
228: }
229: }
230:
231: sub USRMAN {
232: &logthis("USR1: Trying to establish connections again");
233: foreach $thisserver (keys %hostip) {
234: $answer=subreply("ping",$thisserver);
235: &logthis("USR1: Ping $thisserver "
236: ."(pid >$childpid{$thisserver}<, $childatt{thisserver} attempts): "
237: ." >$answer<");
238: }
239: %childatt=();
240: &checkchildren();
241: }
242:
243: # -------------------------------------------------- Non-critical communication
244: sub subreply {
245: my ($cmd,$server)=@_;
246: my $answer='';
247: if ($server ne $perlvar{'lonHostID'}) {
248: my $peerfile="$perlvar{'lonSockDir'}/$server";
249: my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
250: Type => SOCK_STREAM,
251: Timeout => 10)
252: or return "con_lost";
253:
254:
255: $SIG{ALRM}=sub { die "timeout" };
256: $SIG{__DIE__}='DEFAULT';
257: eval {
258: alarm(10);
259: print $sclient "$cmd\n";
260: $answer=<$sclient>;
261: chomp($answer);
262: alarm(0);
263: };
264: if ((!$answer) || ($@=~/timeout/)) { $answer="con_lost"; }
265: $SIG{ALRM}='DEFAULT';
266: $SIG{__DIE__}=\&catchexception;
267: } else { $answer='self_reply'; }
268: return $answer;
269: }
270:
271: # --------------------------------------------------------------------- Logging
272:
273: sub logthis {
274: my $message=shift;
275: my $execdir=$perlvar{'lonDaemons'};
276: my $fh=IO::File->new(">>$execdir/logs/lonc.log");
277: my $now=time;
278: my $local=localtime($now);
279: $lastlog=$local.': '.$message;
280: print $fh "$local ($$): $message\n";
281: }
282:
283:
284: sub logperm {
285: my $message=shift;
286: my $execdir=$perlvar{'lonDaemons'};
287: my $now=time;
288: my $local=localtime($now);
289: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
290: print $fh "$now:$message:$local\n";
291: }
292: # ------------------------------------------------------------------ Log status
293:
294: sub logstatus {
295: my $docdir=$perlvar{'lonDocRoot'};
296: my $fh=IO::File->new(">>$docdir/lon-status/loncstatus.txt");
297: print $fh $$."\t".$status."\t".$lastlog."\n";
298: }
299:
300: sub initnewstatus {
301: my $docdir=$perlvar{'lonDocRoot'};
302: my $fh=IO::File->new(">$docdir/lon-status/loncstatus.txt");
303: my $now=time;
304: my $local=localtime($now);
305: print $fh "LONC status $local - parent $$\n\n";
306: }
307:
308: # -------------------------------------------------------------- Status setting
309:
310: sub status {
311: my $what=shift;
312: my $now=time;
313: my $local=localtime($now);
314: $status=$local.': '.$what;
315: }
316:
317:
318: # ---------------------------------------------------- Fork once and dissociate
319:
320: $fpid=fork;
321: exit if $fpid;
322: die "Couldn't fork: $!" unless defined ($fpid);
323:
324: POSIX::setsid() or die "Can't start new session: $!";
325:
326: # ------------------------------------------------------- Write our PID on disk
327:
328: $execdir=$perlvar{'lonDaemons'};
329: open (PIDSAVE,">$execdir/logs/lonc.pid");
330: print PIDSAVE "$$\n";
331: close(PIDSAVE);
332: &logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
333:
334: # ----------------------------- Ignore signals generated during initial startup
335: $SIG{HUP}=$SIG{USR1}='IGNORE';
336: # ------------------------------------------------------- Now we are on our own
337:
338: # Fork off our children, one for every server
339:
340: &status("Forking ...");
341:
342: foreach $thisserver (keys %hostip) {
343: if (&online($hostname{$thisserver})) {
344: make_new_child($thisserver);
345: }
346: }
347:
348: &logthis("Done starting initial servers");
349: # ----------------------------------------------------- Install signal handlers
350:
351: $SIG{CHLD} = \&REAPER;
352: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
353: $SIG{HUP} = \&HUPSMAN;
354: $SIG{USR1} = \&USRMAN;
355:
356: # And maintain the population.
357: while (1) {
358: &status("Sleeping");
359: sleep; # wait for a signal (i.e., child's death)
360: # See who died and start new one
361: &status("Woke up");
362: foreach $thisserver (keys %hostip) {
363: if (!$childpid{$thisserver}) {
364: if (($childatt{$thisserver}<$childmaxattempts) &&
365: (&online($hostname{$thisserver}))) {
366: $childatt{$thisserver}++;
367: &logthis(
368: "<font color=yellow>INFO: Trying to reconnect for $thisserver "
369: ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
370: make_new_child($thisserver);
371: } else {
372: &logthis(
373: "<font color=yellow>INFO: Skipping $thisserver "
374: ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
375: }
376:
377: }
378: }
379: }
380:
381:
382: sub make_new_child {
383:
384: my $conserver=shift;
385: my $pid;
386: my $sigset;
387: &logthis("Attempting to start child for server $conserver");
388: # block signal for fork
389: $sigset = POSIX::SigSet->new(SIGINT);
390: sigprocmask(SIG_BLOCK, $sigset)
391: or die "Can't block SIGINT for fork: $!\n";
392:
393: die "fork: $!" unless defined ($pid = fork);
394:
395: if ($pid) {
396: # Parent records the child's birth and returns.
397: sigprocmask(SIG_UNBLOCK, $sigset)
398: or die "Can't unblock SIGINT for fork: $!\n";
399: $children{$pid} = $conserver;
400: $childpid{$conserver} = $pid;
401: return;
402: } else {
403: # Child can *not* return from this subroutine.
404: $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
405: $SIG{USR1}= \&logstatus;
406:
407: # unblock signals
408: sigprocmask(SIG_UNBLOCK, $sigset)
409: or die "Can't unblock SIGINT for fork: $!\n";
410:
411: # ----------------------------- This is the modified main program of non-forker
412:
413: $port = "$perlvar{'lonSockDir'}/$conserver";
414:
415: unlink($port);
416:
417: # ---------------------------------------------------- Client to network server
418:
419: &status("Opening TCP: $conserver");
420:
421: unless (
422: $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
423: PeerPort => $perlvar{'londPort'},
424: Proto => "tcp",
425: Type => SOCK_STREAM)
426: ) {
427: my $st=120+int(rand(240));
428: &logthis(
429: "<font color=blue>WARNING: Couldn't connect $conserver ($st secs): $@</font>");
430: sleep($st);
431: exit;
432: };
433: # ----------------------------------------------------------------- Init dialog
434:
435: &status("Init dialogue: $conserver");
436:
437: $SIG{ALRM}=sub { die "timeout" };
438: $SIG{__DIE__}='DEFAULT';
439: eval {
440: alarm(60);
441: print $remotesock "init\n";
442: $answer=<$remotesock>;
443: print $remotesock "$answer";
444: $answer=<$remotesock>;
445: chomp($answer);
446: alarm(0);
447: };
448: $SIG{ALRM}='DEFAULT';
449: $SIG{__DIE__}=\&catchexception;
450:
451: if ($@=~/timeout/) {
452: &logthis("Timed out during init: $conserver");
453: exit;
454: }
455:
456:
457: &logthis("Init reply for $conserver: >$answer<");
458: if ($answer ne 'ok') {
459: my $st=120+int(rand(240));
460: &logthis(
461: "<font color=blue>WARNING: Init failed $conserver ($st secs)</font>");
462: sleep($st);
463: exit;
464: }
465: sleep 5;
466: &status("Ponging $conserver");
467: print $remotesock "pong\n";
468: $answer=<$remotesock>;
469: chomp($answer);
470: &logthis("Pong reply for $conserver: >$answer<");
471: # ----------------------------------------------------------- Initialize cipher
472:
473: &status("Initialize cipher: $conserver");
474: print $remotesock "ekey\n";
475: my $buildkey=<$remotesock>;
476: my $key=$conserver.$perlvar{'lonHostID'};
477: $key=~tr/a-z/A-Z/;
478: $key=~tr/G-P/0-9/;
479: $key=~tr/Q-Z/0-9/;
480: $key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
481: $key=substr($key,0,32);
482: my $cipherkey=pack("H32",$key);
483: if ($cipher=new IDEA $cipherkey) {
484: &logthis("Secure connection initialized: $conserver");
485: } else {
486: my $st=120+int(rand(240));
487: &logthis(
488: "<font color=blue>WARNING: ".
489: "Could not establish secure connection, $conserver ($st secs)!</font>");
490: sleep($st);
491: exit;
492: }
493:
494: # ----------------------------------------- We're online, send delayed messages
495: &status("Checking for delayed messages");
496: my @allbuffered;
497: my $path="$perlvar{'lonSockDir'}/delayed";
498: opendir(DIRHANDLE,$path);
499: @allbuffered=grep /\.$conserver$/, readdir DIRHANDLE;
500: closedir(DIRHANDLE);
501: my $dfname;
502: foreach (@allbuffered) {
503: &status("Sending delayed $conserver $_");
504: $dfname="$path/$_";
505: &logthis($dfname);
506: my $wcmd;
507: {
508: my $dfh=IO::File->new($dfname);
509: $cmd=<$dfh>;
510: }
511: chomp($cmd);
512: my $bcmd=$cmd;
513: if ($cmd =~ /^encrypt\:/) {
514: my $rcmd=$cmd;
515: $rcmd =~ s/^encrypt\://;
516: chomp($rcmd);
517: my $cmdlength=length($rcmd);
518: $rcmd.=" ";
519: my $encrequest='';
520: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
521: $encrequest.=
522: unpack("H16",$cipher->encrypt(substr($rcmd,$encidx,8)));
523: }
524: $cmd="enc:$cmdlength:$encrequest\n";
525: }
526: $SIG{ALRM}=sub { die "timeout" };
527: $SIG{__DIE__}='DEFAULT';
528: eval {
529: alarm(60);
530: print $remotesock "$cmd\n";
531: $answer=<$remotesock>;
532: chomp($answer);
533: alarm(0);
534: };
535: $SIG{ALRM}='DEFAULT';
536: $SIG{__DIE__}=\&catchexception;
537:
538: if (($answer ne '') && ($@!~/timeout/)) {
539: unlink("$dfname");
540: &logthis("Delayed $cmd to $conserver: >$answer<");
541: &logperm("S:$conserver:$bcmd");
542: }
543: }
544:
545: # ------------------------------------------------------- Listen to UNIX socket
546: &status("Opening socket $conserver");
547: unless (
548: $server = IO::Socket::UNIX->new(Local => $port,
549: Type => SOCK_STREAM,
550: Listen => 10 )
551: ) {
552: my $st=120+int(rand(240));
553: &logthis(
554: "<font color=blue>WARNING: ".
555: "Can't make server socket $conserver ($st secs): $@</font>");
556: sleep($st);
557: exit;
558: };
559:
560: # -----------------------------------------------------------------------------
561:
562: &logthis("<font color=green>$conserver online</font>");
563:
564: # -----------------------------------------------------------------------------
565: # begin with empty buffers
566: %inbuffer = ();
567: %outbuffer = ();
568: %ready = ();
569:
570: tie %ready, 'Tie::RefHash';
571:
572: nonblock($server);
573: $select = IO::Select->new($server);
574:
575: # Main loop: check reads/accepts, check writes, check ready to process
576: while (1) {
577: my $client;
578: my $rv;
579: my $data;
580:
581: # check for new information on the connections we have
582:
583: # anything to read or accept?
584: foreach $client ($select->can_read(0.1)) {
585:
586: if ($client == $server) {
587: # accept a new connection
588: &status("Accept new connection: $conserver");
589: $client = $server->accept();
590: $select->add($client);
591: nonblock($client);
592: } else {
593: # read data
594: $data = '';
595: $rv = $client->recv($data, POSIX::BUFSIZ, 0);
596:
597: unless (defined($rv) && length $data) {
598: # This would be the end of file, so close the client
599: delete $inbuffer{$client};
600: delete $outbuffer{$client};
601: delete $ready{$client};
602:
603: &status("Idle $conserver");
604: $select->remove($client);
605: close $client;
606: next;
607: }
608:
609: $inbuffer{$client} .= $data;
610:
611: # test whether the data in the buffer or the data we
612: # just read means there is a complete request waiting
613: # to be fulfilled. If there is, set $ready{$client}
614: # to the requests waiting to be fulfilled.
615: while ($inbuffer{$client} =~ s/(.*\n)//) {
616: push( @{$ready{$client}}, $1 );
617: }
618: }
619: }
620:
621: # Any complete requests to process?
622: foreach $client (keys %ready) {
623: handle($client);
624: }
625:
626: # Buffers to flush?
627: foreach $client ($select->can_write(1)) {
628: # Skip this client if we have nothing to say
629: next unless exists $outbuffer{$client};
630:
631: $rv = $client->send($outbuffer{$client}, 0);
632: unless (defined $rv) {
633: # Whine, but move on.
634: &logthis("I was told I could write, but I can't.\n");
635: next;
636: }
637: $errno=$!;
638: if (($rv == length $outbuffer{$client}) ||
639: ($errno == POSIX::EWOULDBLOCK) || ($errno == 0)) {
640: substr($outbuffer{$client}, 0, $rv) = '';
641: delete $outbuffer{$client} unless length $outbuffer{$client};
642: } else {
643: # Couldn't write all the data, and it wasn't because
644: # it would have blocked. Shutdown and move on.
645:
646: &logthis("Dropping data with ".$errno.": ".
647: length($outbuffer{$client}).", $rv");
648:
649: delete $inbuffer{$client};
650: delete $outbuffer{$client};
651: delete $ready{$client};
652:
653: $select->remove($client);
654: close($client);
655: next;
656: }
657: }
658: }
659: }
660:
661: # ------------------------------------------------------- End of make_new_child
662:
663: # handle($socket) deals with all pending requests for $client
664: sub handle {
665: # requests are in $ready{$client}
666: # send output to $outbuffer{$client}
667: my $client = shift;
668: my $request;
669:
670: foreach $request (@{$ready{$client}}) {
671: # ============================================================= Process request
672: # $request is the text of the request
673: # put text of reply into $outbuffer{$client}
674: # -----------------------------------------------------------------------------
675: if ($request =~ /^encrypt\:/) {
676: my $cmd=$request;
677: $cmd =~ s/^encrypt\://;
678: chomp($cmd);
679: my $cmdlength=length($cmd);
680: $cmd.=" ";
681: my $encrequest='';
682: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
683: $encrequest.=
684: unpack("H16",$cipher->encrypt(substr($cmd,$encidx,8)));
685: }
686: $request="enc:$cmdlength:$encrequest\n";
687: }
688: # --------------------------------------------------------------- Main exchange
689: $SIG{ALRM}=sub { die "timeout" };
690: $SIG{__DIE__}='DEFAULT';
691: eval {
692: alarm(300);
693: &status("Sending $conserver: $request");
694: print $remotesock "$request";
695: &status("Waiting for reply from $conserver: $request");
696: $answer=<$remotesock>;
697: &status("Received reply: $request");
698: alarm(0);
699: };
700: if ($@=~/timeout/) {
701: $answer='';
702: &logthis(
703: "<font color=red>CRITICAL: Timeout $conserver: $request</font>");
704: }
705: $SIG{ALRM}='DEFAULT';
706: $SIG{__DIE__}=\&catchexception;
707:
708:
709: if ($answer) {
710: if ($answer =~ /^enc/) {
711: my ($cmd,$cmdlength,$encinput)=split(/:/,$answer);
712: chomp($encinput);
713: $answer='';
714: for (my $encidx=0;$encidx<length($encinput);$encidx+=16) {
715: $answer.=$cipher->decrypt(
716: pack("H16",substr($encinput,$encidx,16))
717: );
718: }
719: $answer=substr($answer,0,$cmdlength);
720: $answer.="\n";
721: }
722: $outbuffer{$client} .= $answer;
723: } else {
724: $outbuffer{$client} .= "con_lost\n";
725: }
726:
727: # ===================================================== Done processing request
728: }
729: delete $ready{$client};
730: &status("Completed $conserver: $request");
731: # -------------------------------------------------------------- End non-forker
732: }
733: # ---------------------------------------------------------- End make_new_child
734: }
735:
736: # nonblock($socket) puts socket into nonblocking mode
737: sub nonblock {
738: my $socket = shift;
739: my $flags;
740:
741:
742: $flags = fcntl($socket, F_GETFL, 0)
743: or die "Can't get flags for socket: $!\n";
744: fcntl($socket, F_SETFL, $flags | O_NONBLOCK)
745: or die "Can't make socket nonblocking: $!\n";
746: }
747:
748: # ----------------------------------- POD (plain old documentation, CPAN style)
749:
750: =head1 NAME
751:
752: lonc - LON TCP-MySQL-Server Daemon for handling database requests.
753:
754: =head1 SYNOPSIS
755:
756: Should only be run as user=www. This is a command-line script which
757: is invoked by loncron.
758:
759: =head1 DESCRIPTION
760:
761: Provides persistent TCP connections to the other servers in the network
762: through multiplexed domain sockets
763:
764: PID in subdir logs/lonc.pid
765: kill kills
766: HUP restarts
767: USR1 tries to open connections again
768:
769: =head1 README
770:
771: Not yet written.
772:
773: =head1 PREREQUISITES
774:
775: POSIX
776: IO::Socket
777: IO::Select
778: IO::File
779: Socket
780: Fcntl
781: Tie::RefHash
782: Crypt::IDEA
783:
784: =head1 COREQUISITES
785:
786: =head1 OSNAMES
787:
788: linux
789:
790: =head1 SCRIPT CATEGORIES
791:
792: Server/Process
793:
794: =cut
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