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 1.27 2002/02/19 21:49:12 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",20);
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: $hostname{$id}=$name;
165: }
166:
167: close(CONFIG);
168:
169: # -------------------------------------------------------- Routines for forking
170:
171: %children = (); # keys are current child process IDs,
172: # values are hosts
173: %childpid = (); # the other way around
174:
175: %childatt = (); # number of attempts to start server
176: # for ID
177:
178: sub REAPER { # takes care of dead children
179: $SIG{CHLD} = \&REAPER;
180: my $pid = wait;
181: my $wasserver=$children{$pid};
182: &logthis("<font color=red>CRITICAL: "
183: ."Child $pid for server $wasserver died ($childatt{$wasserver})</font>");
184: delete $children{$pid};
185: delete $childpid{$wasserver};
186: my $port = "$perlvar{'lonSockDir'}/$wasserver";
187: unlink($port);
188: }
189:
190: sub hangup {
191: foreach (keys %children) {
192: $wasserver=$children{$_};
193: &status("Closing $wasserver");
194: &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
195: &status("Kill PID $_ for $wasserver");
196: kill ('INT',$_);
197: }
198: }
199:
200: sub HUNTSMAN { # signal handler for SIGINT
201: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
202: &hangup();
203: my $execdir=$perlvar{'lonDaemons'};
204: unlink("$execdir/logs/lonc.pid");
205: &logthis("<font color=red>CRITICAL: Shutting down</font>");
206: exit; # clean up with dignity
207: }
208:
209: sub HUPSMAN { # signal handler for SIGHUP
210: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
211: &hangup();
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: %childatt=();
234: &checkchildren();
235: }
236:
237: # -------------------------------------------------- Non-critical communication
238: sub subreply {
239: my ($cmd,$server)=@_;
240: my $answer='';
241: if ($server ne $perlvar{'lonHostID'}) {
242: my $peerfile="$perlvar{'lonSockDir'}/$server";
243: my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
244: Type => SOCK_STREAM,
245: Timeout => 10)
246: or return "con_lost";
247:
248:
249: $SIG{ALRM}=sub { die "timeout" };
250: $SIG{__DIE__}='DEFAULT';
251: eval {
252: alarm(10);
253: print $sclient "$cmd\n";
254: $answer=<$sclient>;
255: chomp($answer);
256: alarm(0);
257: };
258: if ((!$answer) || ($@=~/timeout/)) { $answer="con_lost"; }
259: $SIG{ALRM}='DEFAULT';
260: $SIG{__DIE__}=\&catchexception;
261: } else { $answer='self_reply'; }
262: return $answer;
263: }
264:
265: # --------------------------------------------------------------------- Logging
266:
267: sub logthis {
268: my $message=shift;
269: my $execdir=$perlvar{'lonDaemons'};
270: my $fh=IO::File->new(">>$execdir/logs/lonc.log");
271: my $now=time;
272: my $local=localtime($now);
273: $lastlog=$local.': '.$message;
274: print $fh "$local ($$): $message\n";
275: }
276:
277:
278: sub logperm {
279: my $message=shift;
280: my $execdir=$perlvar{'lonDaemons'};
281: my $now=time;
282: my $local=localtime($now);
283: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
284: print $fh "$now:$message:$local\n";
285: }
286: # ------------------------------------------------------------------ Log status
287:
288: sub logstatus {
289: my $docdir=$perlvar{'lonDocRoot'};
290: my $fh=IO::File->new(">>$docdir/lon-status/loncstatus.txt");
291: print $fh $$."\t".$status."\t".$lastlog."\n";
292: }
293:
294: sub initnewstatus {
295: my $docdir=$perlvar{'lonDocRoot'};
296: my $fh=IO::File->new(">$docdir/lon-status/loncstatus.txt");
297: my $now=time;
298: my $local=localtime($now);
299: print $fh "LONC status $local - parent $$\n\n";
300: }
301:
302: # -------------------------------------------------------------- Status setting
303:
304: sub status {
305: my $what=shift;
306: my $now=time;
307: my $local=localtime($now);
308: $status=$local.': '.$what;
309: }
310:
311:
312: # ---------------------------------------------------- Fork once and dissociate
313:
314: $fpid=fork;
315: exit if $fpid;
316: die "Couldn't fork: $!" unless defined ($fpid);
317:
318: POSIX::setsid() or die "Can't start new session: $!";
319:
320: # ------------------------------------------------------- Write our PID on disk
321:
322: $execdir=$perlvar{'lonDaemons'};
323: open (PIDSAVE,">$execdir/logs/lonc.pid");
324: print PIDSAVE "$$\n";
325: close(PIDSAVE);
326: &logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
327:
328: # ----------------------------- Ignore signals generated during initial startup
329: $SIG{HUP}=$SIG{USR1}='IGNORE';
330: # ------------------------------------------------------- Now we are on our own
331:
332: # Fork off our children, one for every server
333:
334: &status("Forking ...");
335:
336: foreach $thisserver (keys %hostip) {
337: if (&online($hostname{$thisserver})) {
338: make_new_child($thisserver);
339: }
340: }
341:
342: &logthis("Done starting initial servers");
343: # ----------------------------------------------------- Install signal handlers
344:
345: $SIG{CHLD} = \&REAPER;
346: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
347: $SIG{HUP} = \&HUPSMAN;
348: $SIG{USR1} = \&USRMAN;
349:
350: # And maintain the population.
351: while (1) {
352: &status("Sleeping");
353: sleep; # wait for a signal (i.e., child's death)
354: # See who died and start new one
355: &status("Woke up");
356: foreach $thisserver (keys %hostip) {
357: if (!$childpid{$thisserver}) {
358: if (($childatt{$thisserver}<$childmaxattempts) &&
359: (&online($hostname{$thisserver}))) {
360: $childatt{$thisserver}++;
361: &logthis(
362: "<font color=yellow>INFO: Trying to reconnect for $thisserver "
363: ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
364: make_new_child($thisserver);
365: } else {
366: &logthis(
367: "<font color=yellow>INFO: Skipping $thisserver "
368: ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
369: }
370:
371: }
372: }
373: }
374:
375:
376: sub make_new_child {
377:
378: my $conserver=shift;
379: my $pid;
380: my $sigset;
381: &logthis("Attempting to start child for server $conserver");
382: # block signal for fork
383: $sigset = POSIX::SigSet->new(SIGINT);
384: sigprocmask(SIG_BLOCK, $sigset)
385: or die "Can't block SIGINT for fork: $!\n";
386:
387: die "fork: $!" unless defined ($pid = fork);
388:
389: if ($pid) {
390: # Parent records the child's birth and returns.
391: sigprocmask(SIG_UNBLOCK, $sigset)
392: or die "Can't unblock SIGINT for fork: $!\n";
393: $children{$pid} = $conserver;
394: $childpid{$conserver} = $pid;
395: return;
396: } else {
397: # Child can *not* return from this subroutine.
398: $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
399: $SIG{USR1}= \&logstatus;
400:
401: # unblock signals
402: sigprocmask(SIG_UNBLOCK, $sigset)
403: or die "Can't unblock SIGINT for fork: $!\n";
404:
405: # ----------------------------- This is the modified main program of non-forker
406:
407: $port = "$perlvar{'lonSockDir'}/$conserver";
408:
409: unlink($port);
410:
411: # ---------------------------------------------------- Client to network server
412:
413: &status("Opening TCP: $conserver");
414:
415: unless (
416: $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
417: PeerPort => $perlvar{'londPort'},
418: Proto => "tcp",
419: Type => SOCK_STREAM)
420: ) {
421: my $st=120+int(rand(240));
422: &logthis(
423: "<font color=blue>WARNING: Couldn't connect $conserver ($st secs): $@</font>");
424: sleep($st);
425: exit;
426: };
427: # ----------------------------------------------------------------- Init dialog
428:
429: &status("Init dialogue: $conserver");
430:
431: $SIG{ALRM}=sub { die "timeout" };
432: $SIG{__DIE__}='DEFAULT';
433: eval {
434: alarm(60);
435: print $remotesock "init\n";
436: $answer=<$remotesock>;
437: print $remotesock "$answer";
438: $answer=<$remotesock>;
439: chomp($answer);
440: alarm(0);
441: };
442: $SIG{ALRM}='DEFAULT';
443: $SIG{__DIE__}=\&catchexception;
444:
445: if ($@=~/timeout/) {
446: &logthis("Timed out during init: $conserver");
447: exit;
448: }
449:
450:
451: &logthis("Init reply for $conserver: >$answer<");
452: if ($answer ne 'ok') {
453: my $st=120+int(rand(240));
454: &logthis(
455: "<font color=blue>WARNING: Init failed $conserver ($st secs)</font>");
456: sleep($st);
457: exit;
458: }
459: sleep 5;
460: &status("Ponging $conserver");
461: print $remotesock "pong\n";
462: $answer=<$remotesock>;
463: chomp($answer);
464: &logthis("Pong reply for $conserver: >$answer<");
465: # ----------------------------------------------------------- Initialize cipher
466:
467: &status("Initialize cipher: $conserver");
468: print $remotesock "ekey\n";
469: my $buildkey=<$remotesock>;
470: my $key=$conserver.$perlvar{'lonHostID'};
471: $key=~tr/a-z/A-Z/;
472: $key=~tr/G-P/0-9/;
473: $key=~tr/Q-Z/0-9/;
474: $key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
475: $key=substr($key,0,32);
476: my $cipherkey=pack("H32",$key);
477: if ($cipher=new IDEA $cipherkey) {
478: &logthis("Secure connection initialized: $conserver");
479: } else {
480: my $st=120+int(rand(240));
481: &logthis(
482: "<font color=blue>WARNING: ".
483: "Could not establish secure connection, $conserver ($st secs)!</font>");
484: sleep($st);
485: exit;
486: }
487:
488: # ----------------------------------------- We're online, send delayed messages
489: &status("Checking for delayed messages");
490: my @allbuffered;
491: my $path="$perlvar{'lonSockDir'}/delayed";
492: opendir(DIRHANDLE,$path);
493: @allbuffered=grep /\.$conserver$/, readdir DIRHANDLE;
494: closedir(DIRHANDLE);
495: my $dfname;
496: foreach (@allbuffered) {
497: &status("Sending delayed $conserver $_");
498: $dfname="$path/$_";
499: &logthis($dfname);
500: my $wcmd;
501: {
502: my $dfh=IO::File->new($dfname);
503: $cmd=<$dfh>;
504: }
505: chomp($cmd);
506: my $bcmd=$cmd;
507: if ($cmd =~ /^encrypt\:/) {
508: my $rcmd=$cmd;
509: $rcmd =~ s/^encrypt\://;
510: chomp($rcmd);
511: my $cmdlength=length($rcmd);
512: $rcmd.=" ";
513: my $encrequest='';
514: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
515: $encrequest.=
516: unpack("H16",$cipher->encrypt(substr($rcmd,$encidx,8)));
517: }
518: $cmd="enc:$cmdlength:$encrequest\n";
519: }
520: $SIG{ALRM}=sub { die "timeout" };
521: $SIG{__DIE__}='DEFAULT';
522: eval {
523: alarm(60);
524: print $remotesock "$cmd\n";
525: $answer=<$remotesock>;
526: chomp($answer);
527: alarm(0);
528: };
529: $SIG{ALRM}='DEFAULT';
530: $SIG{__DIE__}=\&catchexception;
531:
532: if (($answer ne '') && ($@!~/timeout/)) {
533: unlink("$dfname");
534: &logthis("Delayed $cmd to $conserver: >$answer<");
535: &logperm("S:$conserver:$bcmd");
536: }
537: }
538:
539: # ------------------------------------------------------- Listen to UNIX socket
540: &status("Opening socket $conserver");
541: unless (
542: $server = IO::Socket::UNIX->new(Local => $port,
543: Type => SOCK_STREAM,
544: Listen => 10 )
545: ) {
546: my $st=120+int(rand(240));
547: &logthis(
548: "<font color=blue>WARNING: ".
549: "Can't make server socket $conserver ($st secs): $@</font>");
550: sleep($st);
551: exit;
552: };
553:
554: # -----------------------------------------------------------------------------
555:
556: &logthis("<font color=green>$conserver online</font>");
557:
558: # -----------------------------------------------------------------------------
559: # begin with empty buffers
560: %inbuffer = ();
561: %outbuffer = ();
562: %ready = ();
563:
564: tie %ready, 'Tie::RefHash';
565:
566: nonblock($server);
567: $select = IO::Select->new($server);
568:
569: # Main loop: check reads/accepts, check writes, check ready to process
570: while (1) {
571: my $client;
572: my $rv;
573: my $data;
574:
575: # check for new information on the connections we have
576:
577: # anything to read or accept?
578: foreach $client ($select->can_read(0.1)) {
579:
580: if ($client == $server) {
581: # accept a new connection
582: &status("Accept new connection: $conserver");
583: $client = $server->accept();
584: $select->add($client);
585: nonblock($client);
586: } else {
587: # read data
588: $data = '';
589: $rv = $client->recv($data, POSIX::BUFSIZ, 0);
590:
591: unless (defined($rv) && length $data) {
592: # This would be the end of file, so close the client
593: delete $inbuffer{$client};
594: delete $outbuffer{$client};
595: delete $ready{$client};
596:
597: &status("Idle $conserver");
598: $select->remove($client);
599: close $client;
600: next;
601: }
602:
603: $inbuffer{$client} .= $data;
604:
605: # test whether the data in the buffer or the data we
606: # just read means there is a complete request waiting
607: # to be fulfilled. If there is, set $ready{$client}
608: # to the requests waiting to be fulfilled.
609: while ($inbuffer{$client} =~ s/(.*\n)//) {
610: push( @{$ready{$client}}, $1 );
611: }
612: }
613: }
614:
615: # Any complete requests to process?
616: foreach $client (keys %ready) {
617: handle($client);
618: }
619:
620: # Buffers to flush?
621: foreach $client ($select->can_write(1)) {
622: # Skip this client if we have nothing to say
623: next unless exists $outbuffer{$client};
624:
625: $rv = $client->send($outbuffer{$client}, 0);
626: unless (defined $rv) {
627: # Whine, but move on.
628: &logthis("I was told I could write, but I can't.\n");
629: next;
630: }
631: $errno=$!;
632: if (($rv == length $outbuffer{$client}) ||
633: ($errno == POSIX::EWOULDBLOCK) || ($errno == 0)) {
634: substr($outbuffer{$client}, 0, $rv) = '';
635: delete $outbuffer{$client} unless length $outbuffer{$client};
636: } else {
637: # Couldn't write all the data, and it wasn't because
638: # it would have blocked. Shutdown and move on.
639:
640: &logthis("Dropping data with ".$errno.": ".
641: length($outbuffer{$client}).", $rv");
642:
643: delete $inbuffer{$client};
644: delete $outbuffer{$client};
645: delete $ready{$client};
646:
647: $select->remove($client);
648: close($client);
649: next;
650: }
651: }
652: }
653: }
654:
655: # ------------------------------------------------------- End of make_new_child
656:
657: # handle($socket) deals with all pending requests for $client
658: sub handle {
659: # requests are in $ready{$client}
660: # send output to $outbuffer{$client}
661: my $client = shift;
662: my $request;
663:
664: foreach $request (@{$ready{$client}}) {
665: # ============================================================= Process request
666: # $request is the text of the request
667: # put text of reply into $outbuffer{$client}
668: # -----------------------------------------------------------------------------
669: if ($request =~ /^encrypt\:/) {
670: my $cmd=$request;
671: $cmd =~ s/^encrypt\://;
672: chomp($cmd);
673: my $cmdlength=length($cmd);
674: $cmd.=" ";
675: my $encrequest='';
676: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
677: $encrequest.=
678: unpack("H16",$cipher->encrypt(substr($cmd,$encidx,8)));
679: }
680: $request="enc:$cmdlength:$encrequest\n";
681: }
682: # --------------------------------------------------------------- Main exchange
683: $SIG{ALRM}=sub { die "timeout" };
684: $SIG{__DIE__}='DEFAULT';
685: eval {
686: alarm(300);
687: &status("Sending $conserver: $request");
688: print $remotesock "$request";
689: &status("Waiting for reply from $conserver: $request");
690: $answer=<$remotesock>;
691: &status("Received reply: $request");
692: alarm(0);
693: };
694: if ($@=~/timeout/) {
695: $answer='';
696: &logthis(
697: "<font color=red>CRITICAL: Timeout $conserver: $request</font>");
698: }
699: $SIG{ALRM}='DEFAULT';
700: $SIG{__DIE__}=\&catchexception;
701:
702:
703: if ($answer) {
704: if ($answer =~ /^enc/) {
705: my ($cmd,$cmdlength,$encinput)=split(/:/,$answer);
706: chomp($encinput);
707: $answer='';
708: for (my $encidx=0;$encidx<length($encinput);$encidx+=16) {
709: $answer.=$cipher->decrypt(
710: pack("H16",substr($encinput,$encidx,16))
711: );
712: }
713: $answer=substr($answer,0,$cmdlength);
714: $answer.="\n";
715: }
716: $outbuffer{$client} .= $answer;
717: } else {
718: $outbuffer{$client} .= "con_lost\n";
719: }
720:
721: # ===================================================== Done processing request
722: }
723: delete $ready{$client};
724: &status("Completed $conserver: $request");
725: # -------------------------------------------------------------- End non-forker
726: }
727: # ---------------------------------------------------------- End make_new_child
728: }
729:
730: # nonblock($socket) puts socket into nonblocking mode
731: sub nonblock {
732: my $socket = shift;
733: my $flags;
734:
735:
736: $flags = fcntl($socket, F_GETFL, 0)
737: or die "Can't get flags for socket: $!\n";
738: fcntl($socket, F_SETFL, $flags | O_NONBLOCK)
739: or die "Can't make socket nonblocking: $!\n";
740: }
741:
742: # ----------------------------------- POD (plain old documentation, CPAN style)
743:
744: =head1 NAME
745:
746: lonc - LON TCP-MySQL-Server Daemon for handling database requests.
747:
748: =head1 SYNOPSIS
749:
750: Should only be run as user=www. This is a command-line script which
751: is invoked by loncron.
752:
753: =head1 DESCRIPTION
754:
755: Provides persistent TCP connections to the other servers in the network
756: through multiplexed domain sockets
757:
758: PID in subdir logs/lonc.pid
759: kill kills
760: HUP restarts
761: USR1 tries to open connections again
762:
763: =head1 README
764:
765: Not yet written.
766:
767: =head1 PREREQUISITES
768:
769: POSIX
770: IO::Socket
771: IO::Select
772: IO::File
773: Socket
774: Fcntl
775: Tie::RefHash
776: Crypt::IDEA
777:
778: =head1 COREQUISITES
779:
780: =head1 OSNAMES
781:
782: linux
783:
784: =head1 SCRIPT CATEGORIES
785:
786: Server/Process
787:
788: =cut
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