Annotation of loncom/lonc, revision 1.31
1.1 albertel 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: #
1.31 ! harris41 8: # $Id: lonc,v 1.30 2002/02/25 20:43:15 www Exp $
1.22 www 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: #
1.1 albertel 32: # PID in subdir logs/lonc.pid
33: # kill kills
34: # HUP restarts
35: # USR1 tries to open connections again
36:
1.2 www 37: # 6/4/99,6/5,6/7,6/8,6/9,6/10,6/11,6/12,7/14,7/19,
1.5 www 38: # 10/8,10/9,10/15,11/18,12/22,
1.10 www 39: # 2/8,7/25 Gerd Kortemeyer
40: # 12/05 Scott Harrison
41: # 12/05 Gerd Kortemeyer
1.23 harris41 42: # YEAR=2001
1.14 www 43: # 01/10/01 Scott Harrison
1.21 www 44: # 03/14/01,03/15,06/12,11/26,11/27,11/28 Gerd Kortemeyer
1.23 harris41 45: # 12/20 Scott Harrison
1.26 www 46: # YEAR=2002
1.29 www 47: # 2/19/02,02/22/02,02/25/02 Gerd Kortemeyer
1.10 www 48: #
1.1 albertel 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;
1.26 www 60: use Net::Ping;
61: use LWP::UserAgent();
1.1 albertel 62:
1.30 www 63: $status='';
64: $lastlog='';
65: $conserver='SHELL';
1.26 www 66:
1.8 harris41 67: # -------------------------------- Set signal handlers to record abnormal exits
68:
1.29 www 69: &status("Init exception handlers");
1.26 www 70: $SIG{QUIT}=\&catchexception;
1.8 harris41 71: $SIG{__DIE__}=\&catchexception;
72:
1.1 albertel 73: # ------------------------------------ Read httpd access.conf and get variables
1.29 www 74: &status("Read access.conf");
1.11 harris41 75: open (CONFIG,"/etc/httpd/conf/access.conf") || die "Can't read access.conf";
1.1 albertel 76:
77: while ($configline=<CONFIG>) {
78: if ($configline =~ /PerlSetVar/) {
79: my ($dummy,$varname,$varvalue)=split(/\s+/,$configline);
1.4 www 80: chomp($varvalue);
1.1 albertel 81: $perlvar{$varname}=$varvalue;
82: }
83: }
84: close(CONFIG);
1.7 www 85:
1.13 harris41 86: # ----------------------------- Make sure this process is running from user=www
1.29 www 87: &status("Check user ID");
1.13 harris41 88: my $wwwid=getpwnam('www');
89: if ($wwwid!=$<) {
90: $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
91: $subj="LON: $perlvar{'lonHostID'} User ID mismatch";
1.14 www 92: system("echo 'User ID mismatch. lonc must be run as user www.' |\
1.13 harris41 93: mailto $emailto -s '$subj' > /dev/null");
94: exit 1;
95: }
96:
1.7 www 97: # --------------------------------------------- Check if other instance running
98:
99: my $pidfile="$perlvar{'lonDaemons'}/logs/lonc.pid";
100:
101: if (-e $pidfile) {
102: my $lfh=IO::File->new("$pidfile");
103: my $pide=<$lfh>;
104: chomp($pide);
1.11 harris41 105: if (kill 0 => $pide) { die "already running"; }
1.7 www 106: }
1.1 albertel 107:
108: # ------------------------------------------------------------- Read hosts file
109:
1.11 harris41 110: open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
1.1 albertel 111:
112: while ($configline=<CONFIG>) {
113: my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
114: chomp($ip);
1.28 www 115: if ($ip) {
116: $hostip{$id}=$ip;
117: $hostname{$id}=$name;
118: }
1.1 albertel 119: }
1.27 www 120:
1.1 albertel 121: close(CONFIG);
122:
123: # -------------------------------------------------------- Routines for forking
124:
125: %children = (); # keys are current child process IDs,
126: # values are hosts
127: %childpid = (); # the other way around
128:
129: %childatt = (); # number of attempts to start server
130: # for ID
131:
1.30 www 132: $childmaxattempts=5;
1.3 www 133:
1.1 albertel 134: # ---------------------------------------------------- Fork once and dissociate
1.29 www 135: &status("Fork and dissociate");
1.1 albertel 136: $fpid=fork;
137: exit if $fpid;
1.11 harris41 138: die "Couldn't fork: $!" unless defined ($fpid);
1.1 albertel 139:
1.11 harris41 140: POSIX::setsid() or die "Can't start new session: $!";
1.1 albertel 141:
1.30 www 142: $conserver='PARENT';
143:
1.1 albertel 144: # ------------------------------------------------------- Write our PID on disk
1.29 www 145: &status("Write PID");
1.1 albertel 146: $execdir=$perlvar{'lonDaemons'};
147: open (PIDSAVE,">$execdir/logs/lonc.pid");
148: print PIDSAVE "$$\n";
149: close(PIDSAVE);
1.5 www 150: &logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
1.1 albertel 151:
152: # ----------------------------- Ignore signals generated during initial startup
153: $SIG{HUP}=$SIG{USR1}='IGNORE';
154: # ------------------------------------------------------- Now we are on our own
155:
156: # Fork off our children, one for every server
157:
1.18 www 158: &status("Forking ...");
159:
1.1 albertel 160: foreach $thisserver (keys %hostip) {
1.26 www 161: if (&online($hostname{$thisserver})) {
162: make_new_child($thisserver);
163: }
1.1 albertel 164: }
165:
166: &logthis("Done starting initial servers");
167: # ----------------------------------------------------- Install signal handlers
168:
169: $SIG{CHLD} = \&REAPER;
170: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
171: $SIG{HUP} = \&HUPSMAN;
172: $SIG{USR1} = \&USRMAN;
173:
174: # And maintain the population.
175: while (1) {
1.18 www 176: &status("Sleeping");
1.1 albertel 177: sleep; # wait for a signal (i.e., child's death)
178: # See who died and start new one
1.18 www 179: &status("Woke up");
1.30 www 180: my $skipping='';
1.1 albertel 181: foreach $thisserver (keys %hostip) {
182: if (!$childpid{$thisserver}) {
1.26 www 183: if (($childatt{$thisserver}<$childmaxattempts) &&
184: (&online($hostname{$thisserver}))) {
1.6 www 185: $childatt{$thisserver}++;
1.5 www 186: &logthis(
187: "<font color=yellow>INFO: Trying to reconnect for $thisserver "
1.30 www 188: ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
1.1 albertel 189: make_new_child($thisserver);
1.26 www 190: } else {
1.30 www 191: $skipping.=$thisserver.' ';
1.26 www 192: }
193:
1.1 albertel 194: }
195: }
1.30 www 196: if ($skipping) {
197: &logthis("<font color=blue>WARNING: Skipped $skipping</font>");
198: }
1.1 albertel 199: }
200:
201:
202: sub make_new_child {
203:
1.30 www 204: $newserver=shift;
1.1 albertel 205: my $pid;
206: my $sigset;
1.30 www 207: &logthis("Attempting to start child for server $newserver");
1.1 albertel 208: # block signal for fork
209: $sigset = POSIX::SigSet->new(SIGINT);
210: sigprocmask(SIG_BLOCK, $sigset)
1.11 harris41 211: or die "Can't block SIGINT for fork: $!\n";
1.1 albertel 212:
1.11 harris41 213: die "fork: $!" unless defined ($pid = fork);
1.1 albertel 214:
215: if ($pid) {
216: # Parent records the child's birth and returns.
217: sigprocmask(SIG_UNBLOCK, $sigset)
1.11 harris41 218: or die "Can't unblock SIGINT for fork: $!\n";
1.30 www 219: $children{$pid} = $newserver;
1.1 albertel 220: $childpid{$conserver} = $pid;
221: return;
222: } else {
1.30 www 223: $conserver=$newserver;
1.1 albertel 224: # Child can *not* return from this subroutine.
225: $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
1.18 www 226: $SIG{USR1}= \&logstatus;
227:
1.1 albertel 228: # unblock signals
229: sigprocmask(SIG_UNBLOCK, $sigset)
1.11 harris41 230: or die "Can't unblock SIGINT for fork: $!\n";
1.1 albertel 231:
232: # ----------------------------- This is the modified main program of non-forker
233:
234: $port = "$perlvar{'lonSockDir'}/$conserver";
235:
236: unlink($port);
1.18 www 237:
1.29 www 238: # -------------------------------------------------------------- Open other end
1.1 albertel 239:
1.29 www 240: &openremote($conserver);
1.1 albertel 241:
1.3 www 242: # ----------------------------------------- We're online, send delayed messages
1.18 www 243: &status("Checking for delayed messages");
1.4 www 244: my @allbuffered;
1.3 www 245: my $path="$perlvar{'lonSockDir'}/delayed";
1.4 www 246: opendir(DIRHANDLE,$path);
247: @allbuffered=grep /\.$conserver$/, readdir DIRHANDLE;
248: closedir(DIRHANDLE);
1.3 www 249: my $dfname;
1.23 harris41 250: foreach (@allbuffered) {
1.30 www 251: &status("Sending delayed: $_");
1.4 www 252: $dfname="$path/$_";
1.29 www 253: &logthis('Sending '.$dfname);
1.3 www 254: my $wcmd;
255: {
256: my $dfh=IO::File->new($dfname);
1.4 www 257: $cmd=<$dfh>;
1.3 www 258: }
259: chomp($cmd);
260: my $bcmd=$cmd;
261: if ($cmd =~ /^encrypt\:/) {
262: my $rcmd=$cmd;
263: $rcmd =~ s/^encrypt\://;
264: chomp($rcmd);
265: my $cmdlength=length($rcmd);
266: $rcmd.=" ";
267: my $encrequest='';
268: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
269: $encrequest.=
270: unpack("H16",$cipher->encrypt(substr($rcmd,$encidx,8)));
271: }
272: $cmd="enc:$cmdlength:$encrequest\n";
273: }
1.20 www 274: $SIG{ALRM}=sub { die "timeout" };
275: $SIG{__DIE__}='DEFAULT';
276: eval {
277: alarm(60);
1.3 www 278: print $remotesock "$cmd\n";
279: $answer=<$remotesock>;
280: chomp($answer);
1.20 www 281: alarm(0);
282: };
283: $SIG{ALRM}='DEFAULT';
284: $SIG{__DIE__}=\&catchexception;
285:
286: if (($answer ne '') && ($@!~/timeout/)) {
1.3 www 287: unlink("$dfname");
1.30 www 288: &logthis("Delayed $cmd: >$answer<");
1.3 www 289: &logperm("S:$conserver:$bcmd");
290: }
1.23 harris41 291: }
1.1 albertel 292:
293: # ------------------------------------------------------- Listen to UNIX socket
1.30 www 294: &status("Opening socket");
1.1 albertel 295: unless (
296: $server = IO::Socket::UNIX->new(Local => $port,
297: Type => SOCK_STREAM,
298: Listen => 10 )
1.5 www 299: ) {
300: my $st=120+int(rand(240));
301: &logthis(
302: "<font color=blue>WARNING: ".
1.30 www 303: "Can't make server socket ($st secs): $@</font>");
1.5 www 304: sleep($st);
1.1 albertel 305: exit;
306: };
307:
308: # -----------------------------------------------------------------------------
309:
1.5 www 310: &logthis("<font color=green>$conserver online</font>");
311:
312: # -----------------------------------------------------------------------------
1.1 albertel 313: # begin with empty buffers
314: %inbuffer = ();
315: %outbuffer = ();
316: %ready = ();
317:
318: tie %ready, 'Tie::RefHash';
319:
320: nonblock($server);
321: $select = IO::Select->new($server);
322:
323: # Main loop: check reads/accepts, check writes, check ready to process
324: while (1) {
325: my $client;
326: my $rv;
327: my $data;
328:
329: # check for new information on the connections we have
330:
331: # anything to read or accept?
1.16 www 332: foreach $client ($select->can_read(0.1)) {
1.1 albertel 333:
334: if ($client == $server) {
335: # accept a new connection
1.18 www 336: &status("Accept new connection: $conserver");
1.1 albertel 337: $client = $server->accept();
338: $select->add($client);
339: nonblock($client);
340: } else {
341: # read data
342: $data = '';
343: $rv = $client->recv($data, POSIX::BUFSIZ, 0);
344:
345: unless (defined($rv) && length $data) {
346: # This would be the end of file, so close the client
347: delete $inbuffer{$client};
348: delete $outbuffer{$client};
349: delete $ready{$client};
350:
1.30 www 351: &status("Idle");
1.1 albertel 352: $select->remove($client);
353: close $client;
354: next;
355: }
356:
357: $inbuffer{$client} .= $data;
358:
359: # test whether the data in the buffer or the data we
360: # just read means there is a complete request waiting
361: # to be fulfilled. If there is, set $ready{$client}
362: # to the requests waiting to be fulfilled.
363: while ($inbuffer{$client} =~ s/(.*\n)//) {
364: push( @{$ready{$client}}, $1 );
365: }
366: }
367: }
368:
369: # Any complete requests to process?
370: foreach $client (keys %ready) {
1.25 albertel 371: handle($client);
1.1 albertel 372: }
373:
374: # Buffers to flush?
375: foreach $client ($select->can_write(1)) {
376: # Skip this client if we have nothing to say
377: next unless exists $outbuffer{$client};
1.25 albertel 378:
1.1 albertel 379: $rv = $client->send($outbuffer{$client}, 0);
1.29 www 380:
1.30 www 381: unless ($outbuffer{$client} eq "con_lost\n") {
1.1 albertel 382: unless (defined $rv) {
383: # Whine, but move on.
1.15 www 384: &logthis("I was told I could write, but I can't.\n");
1.1 albertel 385: next;
386: }
1.15 www 387: $errno=$!;
1.1 albertel 388: if (($rv == length $outbuffer{$client}) ||
1.15 www 389: ($errno == POSIX::EWOULDBLOCK) || ($errno == 0)) {
1.1 albertel 390: substr($outbuffer{$client}, 0, $rv) = '';
391: delete $outbuffer{$client} unless length $outbuffer{$client};
392: } else {
393: # Couldn't write all the data, and it wasn't because
394: # it would have blocked. Shutdown and move on.
1.15 www 395:
396: &logthis("Dropping data with ".$errno.": ".
397: length($outbuffer{$client}).", $rv");
398:
1.1 albertel 399: delete $inbuffer{$client};
400: delete $outbuffer{$client};
401: delete $ready{$client};
402:
403: $select->remove($client);
404: close($client);
405: next;
406: }
1.29 www 407: } else {
408: # -------------------------------------------------------- Wow, connection lost
409: &logthis(
1.30 www 410: "<font color=red>CRITICAL: Closing connection</font>");
411: &status("Connection lost");
1.29 www 412: $remotesock->shutdown(2);
413: &logthis("Attempting to open new connection");
414: &openremote($conserver);
415: }
1.1 albertel 416: }
1.29 www 417:
1.1 albertel 418: }
419: }
1.25 albertel 420:
1.1 albertel 421: # ------------------------------------------------------- End of make_new_child
422:
423: # handle($socket) deals with all pending requests for $client
424: sub handle {
425: # requests are in $ready{$client}
426: # send output to $outbuffer{$client}
427: my $client = shift;
428: my $request;
429:
430: foreach $request (@{$ready{$client}}) {
431: # ============================================================= Process request
432: # $request is the text of the request
433: # put text of reply into $outbuffer{$client}
1.29 www 434: # ------------------------------------------------------------ Is this the end?
435: if ($request eq "close_connection_exit\n") {
1.30 www 436: &status("Request close connection");
1.29 www 437: &logthis(
1.30 www 438: "<font color=red>CRITICAL: Request Close Connection</font>");
1.29 www 439: $remotesock->shutdown(2);
440: $server->close();
441: exit;
442: }
1.1 albertel 443: # -----------------------------------------------------------------------------
444: if ($request =~ /^encrypt\:/) {
445: my $cmd=$request;
446: $cmd =~ s/^encrypt\://;
447: chomp($cmd);
448: my $cmdlength=length($cmd);
449: $cmd.=" ";
450: my $encrequest='';
451: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
452: $encrequest.=
453: unpack("H16",$cipher->encrypt(substr($cmd,$encidx,8)));
454: }
455: $request="enc:$cmdlength:$encrequest\n";
456: }
1.19 www 457: # --------------------------------------------------------------- Main exchange
458: $SIG{ALRM}=sub { die "timeout" };
459: $SIG{__DIE__}='DEFAULT';
460: eval {
461: alarm(300);
1.30 www 462: &status("Sending: $request");
1.1 albertel 463: print $remotesock "$request";
1.18 www 464: &status("Waiting for reply from $conserver: $request");
1.1 albertel 465: $answer=<$remotesock>;
1.18 www 466: &status("Received reply: $request");
1.19 www 467: alarm(0);
468: };
469: if ($@=~/timeout/) {
470: $answer='';
471: &logthis(
1.30 www 472: "<font color=red>CRITICAL: Timeout: $request</font>");
1.19 www 473: }
474: $SIG{ALRM}='DEFAULT';
475: $SIG{__DIE__}=\&catchexception;
476:
477:
1.1 albertel 478: if ($answer) {
479: if ($answer =~ /^enc/) {
480: my ($cmd,$cmdlength,$encinput)=split(/:/,$answer);
481: chomp($encinput);
482: $answer='';
483: for (my $encidx=0;$encidx<length($encinput);$encidx+=16) {
484: $answer.=$cipher->decrypt(
485: pack("H16",substr($encinput,$encidx,16))
486: );
487: }
488: $answer=substr($answer,0,$cmdlength);
489: $answer.="\n";
490: }
491: $outbuffer{$client} .= $answer;
492: } else {
493: $outbuffer{$client} .= "con_lost\n";
494: }
495:
1.30 www 496: &status("Completed: $request");
497:
1.1 albertel 498: # ===================================================== Done processing request
499: }
500: delete $ready{$client};
501: # -------------------------------------------------------------- End non-forker
502: }
503: # ---------------------------------------------------------- End make_new_child
1.25 albertel 504: }
1.1 albertel 505:
506: # nonblock($socket) puts socket into nonblocking mode
507: sub nonblock {
508: my $socket = shift;
509: my $flags;
510:
511:
512: $flags = fcntl($socket, F_GETFL, 0)
1.11 harris41 513: or die "Can't get flags for socket: $!\n";
1.1 albertel 514: fcntl($socket, F_SETFL, $flags | O_NONBLOCK)
1.11 harris41 515: or die "Can't make socket nonblocking: $!\n";
1.29 www 516: }
517:
518:
519: sub openremote {
520: # ---------------------------------------------------- Client to network server
521:
522: my $conserver=shift;
523:
1.30 www 524: &status("Opening TCP");
1.29 www 525:
526: unless (
527: $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
528: PeerPort => $perlvar{'londPort'},
529: Proto => "tcp",
530: Type => SOCK_STREAM)
531: ) {
532: my $st=120+int(rand(240));
533: &logthis(
1.30 www 534: "<font color=blue>WARNING: Couldn't connect ($st secs): $@</font>");
1.29 www 535: sleep($st);
536: exit;
537: };
538: # ----------------------------------------------------------------- Init dialog
539:
540: &status("Init dialogue: $conserver");
541:
542: $SIG{ALRM}=sub { die "timeout" };
543: $SIG{__DIE__}='DEFAULT';
544: eval {
545: alarm(60);
546: print $remotesock "init\n";
547: $answer=<$remotesock>;
548: print $remotesock "$answer";
549: $answer=<$remotesock>;
550: chomp($answer);
551: alarm(0);
552: };
553: $SIG{ALRM}='DEFAULT';
554: $SIG{__DIE__}=\&catchexception;
555:
556: if ($@=~/timeout/) {
1.30 www 557: &logthis("Timed out during init");
1.29 www 558: exit;
559: }
560:
561: if ($answer ne 'ok') {
1.30 www 562: &logthis("Init reply: >$answer<");
1.29 www 563: my $st=120+int(rand(240));
564: &logthis(
1.30 www 565: "<font color=blue>WARNING: Init failed ($st secs)</font>");
1.29 www 566: sleep($st);
567: exit;
568: }
569:
570: sleep 5;
1.30 www 571: &status("Ponging");
1.29 www 572: print $remotesock "pong\n";
573: $answer=<$remotesock>;
574: chomp($answer);
1.30 www 575: if ($answer!~/^$conserver/) {
576: &logthis("Pong reply: >$answer<");
1.29 www 577: }
578: # ----------------------------------------------------------- Initialize cipher
579:
1.30 www 580: &status("Initialize cipher");
1.29 www 581: print $remotesock "ekey\n";
582: my $buildkey=<$remotesock>;
583: my $key=$conserver.$perlvar{'lonHostID'};
584: $key=~tr/a-z/A-Z/;
585: $key=~tr/G-P/0-9/;
586: $key=~tr/Q-Z/0-9/;
587: $key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
588: $key=substr($key,0,32);
589: my $cipherkey=pack("H32",$key);
590: if ($cipher=new IDEA $cipherkey) {
1.30 www 591: &logthis("Secure connection initialized");
1.29 www 592: } else {
593: my $st=120+int(rand(240));
594: &logthis(
595: "<font color=blue>WARNING: ".
1.30 www 596: "Could not establish secure connection ($st secs)!</font>");
1.29 www 597: sleep($st);
598: exit;
599: }
600:
1.8 harris41 601: }
1.30 www 602:
603:
604:
605: # grabs exception and records it to log before exiting
606: sub catchexception {
607: my ($signal)=@_;
608: $SIG{QUIT}='DEFAULT';
609: $SIG{__DIE__}='DEFAULT';
610: chomp($signal);
611: &logthis("<font color=red>CRITICAL: "
612: ."ABNORMAL EXIT. Child $$ for server [$wasserver] died through "
613: ."\"$signal\" with parameter [$@]</font>");
614: die($@);
615: }
616:
617: # -------------------------------------- Routines to see if other box available
618:
619: sub online {
620: my $host=shift;
621: &status("Pinging ".$host);
622: my $p=Net::Ping->new("tcp",20);
623: my $online=$p->ping("$host");
624: $p->close();
625: undef ($p);
626: return $online;
627: }
628:
629: sub connected {
630: my ($local,$remote)=@_;
631: &status("Checking connection $local to $remote");
632: $local=~s/\W//g;
633: $remote=~s/\W//g;
634:
635: unless ($hostname{$local}) { return 'local_unknown'; }
636: unless ($hostname{$remote}) { return 'remote_unknown'; }
637:
638: unless (&online($hostname{$local})) { return 'local_offline'; }
639:
640: my $ua=new LWP::UserAgent;
641:
642: my $request=new HTTP::Request('GET',
643: "http://".$hostname{$local}.'/cgi-bin/ping.pl?'.$remote);
644:
645: my $response=$ua->request($request);
646:
647: unless ($response->is_success) { return 'local_error'; }
648:
649: my $reply=$response->content;
650: $reply=(split("\n",$reply))[0];
651: $reply=~s/\W//g;
652: if ($reply ne $remote) { return $reply; }
653: return 'ok';
654: }
655:
656:
657: sub REAPER { # takes care of dead children
658: $SIG{CHLD} = \&REAPER;
659: my $pid = wait;
660: my $wasserver=$children{$pid};
661: &logthis("<font color=red>CRITICAL: "
662: ."Child $pid for server $wasserver died ($childatt{$wasserver})</font>");
663: delete $children{$pid};
664: delete $childpid{$wasserver};
665: my $port = "$perlvar{'lonSockDir'}/$wasserver";
666: unlink($port);
667: }
668:
669: sub hangup {
670: foreach (keys %children) {
671: $wasserver=$children{$_};
672: &status("Closing $wasserver");
673: &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
674: &status("Kill PID $_ for $wasserver");
675: kill ('INT',$_);
676: }
677: }
678:
679: sub HUNTSMAN { # signal handler for SIGINT
680: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
681: &hangup();
682: my $execdir=$perlvar{'lonDaemons'};
683: unlink("$execdir/logs/lonc.pid");
684: &logthis("<font color=red>CRITICAL: Shutting down</font>");
685: exit; # clean up with dignity
686: }
687:
688: sub HUPSMAN { # signal handler for SIGHUP
689: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
690: &hangup();
691: &logthis("<font color=red>CRITICAL: Restarting</font>");
692: unlink("$execdir/logs/lonc.pid");
693: my $execdir=$perlvar{'lonDaemons'};
694: exec("$execdir/lonc"); # here we go again
695: }
696:
697: sub checkchildren {
698: &initnewstatus();
699: &logstatus();
700: &logthis('Going to check on the children');
701: foreach (sort keys %children) {
702: sleep 1;
703: unless (kill 'USR1' => $_) {
704: &logthis ('<font color=red>CRITICAL: Child '.$_.' is dead</font>');
705: &logstatus($$.' is dead');
706: }
707: }
708: }
709:
710: sub USRMAN {
711: &logthis("USR1: Trying to establish connections again");
712: %childatt=();
713: &checkchildren();
714: }
715:
716: # -------------------------------------------------- Non-critical communication
717: sub subreply {
718: my ($cmd,$server)=@_;
719: my $answer='';
720: if ($server ne $perlvar{'lonHostID'}) {
721: my $peerfile="$perlvar{'lonSockDir'}/$server";
722: my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
723: Type => SOCK_STREAM,
724: Timeout => 10)
725: or return "con_lost";
726:
727:
728: $SIG{ALRM}=sub { die "timeout" };
729: $SIG{__DIE__}='DEFAULT';
730: eval {
731: alarm(10);
732: print $sclient "$cmd\n";
733: $answer=<$sclient>;
734: chomp($answer);
735: alarm(0);
736: };
737: if ((!$answer) || ($@=~/timeout/)) { $answer="con_lost"; }
738: $SIG{ALRM}='DEFAULT';
739: $SIG{__DIE__}=\&catchexception;
740: } else { $answer='self_reply'; }
741: return $answer;
742: }
743:
744: # --------------------------------------------------------------------- Logging
745:
746: sub logthis {
747: my $message=shift;
748: my $execdir=$perlvar{'lonDaemons'};
749: my $fh=IO::File->new(">>$execdir/logs/lonc.log");
750: my $now=time;
751: my $local=localtime($now);
752: $lastlog=$local.': '.$message;
753: print $fh "$local ($$) [$conserver] [$status]: $message\n";
754: }
755:
756:
757: sub logperm {
758: my $message=shift;
759: my $execdir=$perlvar{'lonDaemons'};
760: my $now=time;
761: my $local=localtime($now);
762: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
763: print $fh "$now:$message:$local\n";
764: }
765: # ------------------------------------------------------------------ Log status
766:
767: sub logstatus {
768: my $docdir=$perlvar{'lonDocRoot'};
769: my $fh=IO::File->new(">>$docdir/lon-status/loncstatus.txt");
770: print $fh $$."\t".$conserver."\t".$status."\t".$lastlog."\n";
771: }
772:
773: sub initnewstatus {
774: my $docdir=$perlvar{'lonDocRoot'};
775: my $fh=IO::File->new(">$docdir/lon-status/loncstatus.txt");
776: my $now=time;
777: my $local=localtime($now);
778: print $fh "LONC status $local - parent $$\n\n";
779: }
780:
781: # -------------------------------------------------------------- Status setting
782:
783: sub status {
784: my $what=shift;
785: my $now=time;
786: my $local=localtime($now);
787: $status=$local.': '.$what;
788: }
789:
790:
1.1 albertel 791:
1.23 harris41 792: # ----------------------------------- POD (plain old documentation, CPAN style)
793:
794: =head1 NAME
795:
796: lonc - LON TCP-MySQL-Server Daemon for handling database requests.
797:
798: =head1 SYNOPSIS
799:
1.31 ! harris41 800: Usage: B<lonc>
! 801:
1.23 harris41 802: Should only be run as user=www. This is a command-line script which
1.31 ! harris41 803: is invoked by B<loncron>. There is no expectation that a typical user
! 804: will manually start B<lonc> from the command-line. (In other words,
! 805: DO NOT START B<lonc> YOURSELF.)
1.23 harris41 806:
807: =head1 DESCRIPTION
808:
809: Provides persistent TCP connections to the other servers in the network
810: through multiplexed domain sockets
811:
1.31 ! harris41 812: B<lonc> forks off children processes that correspond to the other servers
! 813: in the network. Management of these processes can be done at the
! 814: parent process level or the child process level.
! 815:
! 816: B<logs/lonc.log> is the location of log messages.
! 817:
! 818: The process management is now explained in terms of linux shell commands,
! 819: subroutines internal to this code, and signal assignments:
! 820:
! 821: =over 4
! 822:
! 823: =item *
! 824:
! 825: PID is stored in B<logs/lonc.pid>
! 826:
! 827: This is the process id number of the parent B<lonc> process.
! 828:
! 829: =item *
! 830:
! 831: SIGTERM and SIGINT
! 832:
! 833: Parent signal assignment:
! 834: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
! 835:
! 836: Child signal assignment:
! 837: $SIG{INT} = 'DEFAULT'; (and SIGTERM is DEFAULT also)
! 838: (The child dies and a SIGALRM is sent to parent, awaking parent from slumber
! 839: to restart a new child.)
! 840:
! 841: Command-line invocations:
! 842: B<kill> B<-s> SIGTERM I<PID>
! 843: B<kill> B<-s> SIGINT I<PID>
! 844:
! 845: Subroutine B<HUNTSMAN>:
! 846: This is only invoked for the B<lonc> parent I<PID>.
! 847: This kills all the children, and then the parent.
! 848: The B<lonc.pid> file is cleared.
! 849:
! 850: =item *
! 851:
! 852: SIGHUP
! 853:
! 854: Current bug:
! 855: This signal can only be processed the first time
! 856: on the parent process. Subsequent SIGHUP signals
! 857: have no effect.
! 858:
! 859: Parent signal assignment:
! 860: $SIG{HUP} = \&HUPSMAN;
! 861:
! 862: Child signal assignment:
! 863: none (nothing happens)
! 864:
! 865: Command-line invocations:
! 866: B<kill> B<-s> SIGHUP I<PID>
! 867:
! 868: Subroutine B<HUPSMAN>:
! 869: This is only invoked for the B<lonc> parent I<PID>,
! 870: This kills all the children, and then the parent.
! 871: The B<lonc.pid> file is cleared.
! 872:
! 873: =item *
! 874:
! 875: SIGUSR1
! 876:
! 877: Parent signal assignment:
! 878: $SIG{USR1} = \&USRMAN;
! 879:
! 880: Child signal assignment:
! 881: $SIG{USR1}= \&logstatus;
! 882:
! 883: Command-line invocations:
! 884: B<kill> B<-s> SIGUSR1 I<PID>
! 885:
! 886: Subroutine B<USRMAN>:
! 887: When invoked for the B<lonc> parent I<PID>,
! 888: SIGUSR1 is sent to all the children, and the status of
! 889: each connection is logged.
! 890:
! 891: =item *
! 892:
! 893: SIGCHLD
! 894:
! 895: Parent signal assignment:
! 896: $SIG{CHLD} = \&REAPER;
! 897:
! 898: Child signal assignment:
! 899: none
! 900:
! 901: Command-line invocations:
! 902: B<kill> B<-s> SIGCHLD I<PID>
1.23 harris41 903:
1.31 ! harris41 904: Subroutine B<REAPER>:
! 905: This is only invoked for the B<lonc> parent I<PID>.
! 906: Information pertaining to the child is removed.
! 907: The socket port is cleaned up.
1.23 harris41 908:
1.31 ! harris41 909: =back
1.23 harris41 910:
911: =head1 PREREQUISITES
912:
913: POSIX
914: IO::Socket
915: IO::Select
916: IO::File
917: Socket
918: Fcntl
919: Tie::RefHash
920: Crypt::IDEA
921:
922: =head1 COREQUISITES
923:
924: =head1 OSNAMES
925:
926: linux
927:
928: =head1 SCRIPT CATEGORIES
929:
930: Server/Process
931:
932: =cut
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