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: # PID in subdir logs/lonc.pid
9: # kill kills
10: # HUP restarts
11: # USR1 tries to open connections again
12:
13: # 6/4/99,6/5,6/7,6/8,6/9,6/10,6/11,6/12,7/14,7/19,
14: # 10/8,10/9,10/15,11/18,12/22,
15: # 2/8,7/25 Gerd Kortemeyer
16: # 12/05 Scott Harrison
17: # 12/05 Gerd Kortemeyer
18: # 01/10/01 Scott Harrison
19: # 03/14/01,03/15,06/12,11/26,11/27,11/28 Gerd Kortemeyer
20: #
21: # based on nonforker from Perl Cookbook
22: # - server who multiplexes without forking
23:
24: use POSIX;
25: use IO::Socket;
26: use IO::Select;
27: use IO::File;
28: use Socket;
29: use Fcntl;
30: use Tie::RefHash;
31: use Crypt::IDEA;
32:
33: my $status='';
34: my $lastlog='';
35:
36: # grabs exception and records it to log before exiting
37: sub catchexception {
38: my ($signal)=@_;
39: $SIG{'QUIT'}='DEFAULT';
40: $SIG{__DIE__}='DEFAULT';
41: &logthis("<font color=red>CRITICAL: "
42: ."ABNORMAL EXIT. Child $$ for server $wasserver died through "
43: ."\"$signal\" with this parameter->[$@]</font>");
44: die($@);
45: }
46:
47: $childmaxattempts=5;
48:
49: # -------------------------------- Set signal handlers to record abnormal exits
50:
51: $SIG{'QUIT'}=\&catchexception;
52: $SIG{__DIE__}=\&catchexception;
53:
54: # ------------------------------------ Read httpd access.conf and get variables
55:
56: open (CONFIG,"/etc/httpd/conf/access.conf") || die "Can't read access.conf";
57:
58: while ($configline=<CONFIG>) {
59: if ($configline =~ /PerlSetVar/) {
60: my ($dummy,$varname,$varvalue)=split(/\s+/,$configline);
61: chomp($varvalue);
62: $perlvar{$varname}=$varvalue;
63: }
64: }
65: close(CONFIG);
66:
67: # ----------------------------- Make sure this process is running from user=www
68: my $wwwid=getpwnam('www');
69: if ($wwwid!=$<) {
70: $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
71: $subj="LON: $perlvar{'lonHostID'} User ID mismatch";
72: system("echo 'User ID mismatch. lonc must be run as user www.' |\
73: mailto $emailto -s '$subj' > /dev/null");
74: exit 1;
75: }
76:
77: # --------------------------------------------- Check if other instance running
78:
79: my $pidfile="$perlvar{'lonDaemons'}/logs/lonc.pid";
80:
81: if (-e $pidfile) {
82: my $lfh=IO::File->new("$pidfile");
83: my $pide=<$lfh>;
84: chomp($pide);
85: if (kill 0 => $pide) { die "already running"; }
86: }
87:
88: # ------------------------------------------------------------- Read hosts file
89:
90: open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
91:
92: while ($configline=<CONFIG>) {
93: my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
94: chomp($ip);
95: $hostip{$id}=$ip;
96: }
97: close(CONFIG);
98:
99: # -------------------------------------------------------- Routines for forking
100:
101: %children = (); # keys are current child process IDs,
102: # values are hosts
103: %childpid = (); # the other way around
104:
105: %childatt = (); # number of attempts to start server
106: # for ID
107:
108: sub REAPER { # takes care of dead children
109: $SIG{CHLD} = \&REAPER;
110: my $pid = wait;
111: my $wasserver=$children{$pid};
112: &logthis("<font color=red>CRITICAL: "
113: ."Child $pid for server $wasserver died ($childatt{$wasserver})</font>");
114: delete $children{$pid};
115: delete $childpid{$wasserver};
116: my $port = "$perlvar{'lonSockDir'}/$wasserver";
117: unlink($port);
118: }
119:
120: sub HUNTSMAN { # signal handler for SIGINT
121: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
122: map {
123: $wasserver=$children{$_};
124: &status("Closing $wasserver");
125: &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
126: &status("Kill PID $_ for $wasserver");
127: kill ('INT',$_);
128: } keys %children;
129: my $execdir=$perlvar{'lonDaemons'};
130: unlink("$execdir/logs/lonc.pid");
131: &logthis("<font color=red>CRITICAL: Shutting down</font>");
132: exit; # clean up with dignity
133: }
134:
135: sub HUPSMAN { # signal handler for SIGHUP
136: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
137: map {
138: $wasserver=$children{$_};
139: &status("Closing $wasserver");
140: &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
141: &status("Kill PID $_ for $wasserver");
142: kill ('INT',$_);
143: } keys %children;
144: &logthis("<font color=red>CRITICAL: Restarting</font>");
145: unlink("$execdir/logs/lonc.pid");
146: my $execdir=$perlvar{'lonDaemons'};
147: exec("$execdir/lonc"); # here we go again
148: }
149:
150: sub checkchildren {
151: &initnewstatus();
152: &logstatus();
153: &logthis('Going to check on the children');
154: map {
155: sleep 1;
156: unless (kill 'USR1' => $_) {
157: &logthis ('Child '.$_.' is dead');
158: &logstatus($$.' is dead');
159: }
160: } sort keys %children;
161: }
162:
163: sub USRMAN {
164: &logthis("USR1: Trying to establish connections again");
165: foreach $thisserver (keys %hostip) {
166: $answer=subreply("ping",$thisserver);
167: &logthis("USR1: Ping $thisserver "
168: ."(pid >$childpid{$thisserver}<, $childatt{thisserver} attempts): "
169: ." >$answer<");
170: }
171: %childatt=();
172: &checkchildren();
173: }
174:
175: # -------------------------------------------------- Non-critical communication
176: sub subreply {
177: my ($cmd,$server)=@_;
178: my $answer='';
179: if ($server ne $perlvar{'lonHostID'}) {
180: my $peerfile="$perlvar{'lonSockDir'}/$server";
181: my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
182: Type => SOCK_STREAM,
183: Timeout => 10)
184: or return "con_lost";
185:
186:
187: $SIG{ALRM}=sub { die "timeout" };
188: $SIG{__DIE__}='DEFAULT';
189: eval {
190: alarm(10);
191: print $sclient "$cmd\n";
192: $answer=<$sclient>;
193: chomp($answer);
194: alarm(0);
195: };
196: if ((!$answer) || ($@=~/timeout/)) { $answer="con_lost"; }
197: $SIG{ALRM}='DEFAULT';
198: $SIG{__DIE__}=\&catchexception;
199: } else { $answer='self_reply'; }
200: return $answer;
201: }
202:
203: # --------------------------------------------------------------------- Logging
204:
205: sub logthis {
206: my $message=shift;
207: my $execdir=$perlvar{'lonDaemons'};
208: my $fh=IO::File->new(">>$execdir/logs/lonc.log");
209: my $now=time;
210: my $local=localtime($now);
211: $lastlog=$local.': '.$message;
212: print $fh "$local ($$): $message\n";
213: }
214:
215:
216: sub logperm {
217: my $message=shift;
218: my $execdir=$perlvar{'lonDaemons'};
219: my $now=time;
220: my $local=localtime($now);
221: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
222: print $fh "$now:$message:$local\n";
223: }
224: # ------------------------------------------------------------------ Log status
225:
226: sub logstatus {
227: my $docdir=$perlvar{'lonDocRoot'};
228: my $fh=IO::File->new(">>$docdir/lon-status/loncstatus.txt");
229: print $fh $$."\t".$status."\t".$lastlog."\n";
230: }
231:
232: sub initnewstatus {
233: my $docdir=$perlvar{'lonDocRoot'};
234: my $fh=IO::File->new(">$docdir/lon-status/loncstatus.txt");
235: my $now=time;
236: my $local=localtime($now);
237: print $fh "LONC status $local - parent $$\n\n";
238: }
239:
240: # -------------------------------------------------------------- Status setting
241:
242: sub status {
243: my $what=shift;
244: my $now=time;
245: my $local=localtime($now);
246: $status=$local.': '.$what;
247: }
248:
249:
250: # ---------------------------------------------------- Fork once and dissociate
251:
252: $fpid=fork;
253: exit if $fpid;
254: die "Couldn't fork: $!" unless defined ($fpid);
255:
256: POSIX::setsid() or die "Can't start new session: $!";
257:
258: # ------------------------------------------------------- Write our PID on disk
259:
260: $execdir=$perlvar{'lonDaemons'};
261: open (PIDSAVE,">$execdir/logs/lonc.pid");
262: print PIDSAVE "$$\n";
263: close(PIDSAVE);
264: &logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
265:
266: # ----------------------------- Ignore signals generated during initial startup
267: $SIG{HUP}=$SIG{USR1}='IGNORE';
268: # ------------------------------------------------------- Now we are on our own
269:
270: # Fork off our children, one for every server
271:
272: &status("Forking ...");
273:
274: foreach $thisserver (keys %hostip) {
275: make_new_child($thisserver);
276: }
277:
278: &logthis("Done starting initial servers");
279: # ----------------------------------------------------- Install signal handlers
280:
281: $SIG{CHLD} = \&REAPER;
282: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
283: $SIG{HUP} = \&HUPSMAN;
284: $SIG{USR1} = \&USRMAN;
285:
286: # And maintain the population.
287: while (1) {
288: &status("Sleeping");
289: sleep; # wait for a signal (i.e., child's death)
290: # See who died and start new one
291: &status("Woke up");
292: foreach $thisserver (keys %hostip) {
293: if (!$childpid{$thisserver}) {
294: if ($childatt{$thisserver}<$childmaxattempts) {
295: $childatt{$thisserver}++;
296: &logthis(
297: "<font color=yellow>INFO: Trying to reconnect for $thisserver "
298: ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
299: make_new_child($thisserver);
300: }
301: }
302: }
303: }
304:
305:
306: sub make_new_child {
307:
308: my $conserver=shift;
309: my $pid;
310: my $sigset;
311: &logthis("Attempting to start child for server $conserver");
312: # block signal for fork
313: $sigset = POSIX::SigSet->new(SIGINT);
314: sigprocmask(SIG_BLOCK, $sigset)
315: or die "Can't block SIGINT for fork: $!\n";
316:
317: die "fork: $!" unless defined ($pid = fork);
318:
319: if ($pid) {
320: # Parent records the child's birth and returns.
321: sigprocmask(SIG_UNBLOCK, $sigset)
322: or die "Can't unblock SIGINT for fork: $!\n";
323: $children{$pid} = $conserver;
324: $childpid{$conserver} = $pid;
325: return;
326: } else {
327: # Child can *not* return from this subroutine.
328: $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
329: $SIG{USR1}= \&logstatus;
330:
331: # unblock signals
332: sigprocmask(SIG_UNBLOCK, $sigset)
333: or die "Can't unblock SIGINT for fork: $!\n";
334:
335: # ----------------------------- This is the modified main program of non-forker
336:
337: $port = "$perlvar{'lonSockDir'}/$conserver";
338:
339: unlink($port);
340:
341: # ---------------------------------------------------- Client to network server
342:
343: &status("Opening TCP: $conserver");
344:
345: unless (
346: $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
347: PeerPort => $perlvar{'londPort'},
348: Proto => "tcp",
349: Type => SOCK_STREAM)
350: ) {
351: my $st=120+int(rand(240));
352: &logthis(
353: "<font color=blue>WARNING: Couldn't connect $conserver ($st secs): $@</font>");
354: sleep($st);
355: exit;
356: };
357: # ----------------------------------------------------------------- Init dialog
358:
359: &status("Init dialogue: $conserver");
360:
361: $SIG{ALRM}=sub { die "timeout" };
362: $SIG{__DIE__}='DEFAULT';
363: eval {
364: alarm(60);
365: print $remotesock "init\n";
366: $answer=<$remotesock>;
367: print $remotesock "$answer";
368: $answer=<$remotesock>;
369: chomp($answer);
370: alarm(0);
371: };
372: $SIG{ALRM}='DEFAULT';
373: $SIG{__DIE__}=\&catchexception;
374:
375: if ($@=~/timeout/) {
376: &logthis("Timed out during init: $conserver");
377: exit;
378: }
379:
380:
381: &logthis("Init reply for $conserver: >$answer<");
382: if ($answer ne 'ok') {
383: my $st=120+int(rand(240));
384: &logthis(
385: "<font color=blue>WARNING: Init failed $conserver ($st secs)</font>");
386: sleep($st);
387: exit;
388: }
389: sleep 5;
390: &status("Ponging $conserver");
391: print $remotesock "pong\n";
392: $answer=<$remotesock>;
393: chomp($answer);
394: &logthis("Pong reply for $conserver: >$answer<");
395: # ----------------------------------------------------------- Initialize cipher
396:
397: &status("Initialize cipher: $conserver");
398: print $remotesock "ekey\n";
399: my $buildkey=<$remotesock>;
400: my $key=$conserver.$perlvar{'lonHostID'};
401: $key=~tr/a-z/A-Z/;
402: $key=~tr/G-P/0-9/;
403: $key=~tr/Q-Z/0-9/;
404: $key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
405: $key=substr($key,0,32);
406: my $cipherkey=pack("H32",$key);
407: if ($cipher=new IDEA $cipherkey) {
408: &logthis("Secure connection initialized: $conserver");
409: } else {
410: my $st=120+int(rand(240));
411: &logthis(
412: "<font color=blue>WARNING: ".
413: "Could not establish secure connection, $conserver ($st secs)!</font>");
414: sleep($st);
415: exit;
416: }
417:
418: # ----------------------------------------- We're online, send delayed messages
419: &status("Checking for delayed messages");
420: my @allbuffered;
421: my $path="$perlvar{'lonSockDir'}/delayed";
422: opendir(DIRHANDLE,$path);
423: @allbuffered=grep /\.$conserver$/, readdir DIRHANDLE;
424: closedir(DIRHANDLE);
425: my $dfname;
426: map {
427: &status("Sending delayed $conserver $_");
428: $dfname="$path/$_";
429: &logthis($dfname);
430: my $wcmd;
431: {
432: my $dfh=IO::File->new($dfname);
433: $cmd=<$dfh>;
434: }
435: chomp($cmd);
436: my $bcmd=$cmd;
437: if ($cmd =~ /^encrypt\:/) {
438: my $rcmd=$cmd;
439: $rcmd =~ s/^encrypt\://;
440: chomp($rcmd);
441: my $cmdlength=length($rcmd);
442: $rcmd.=" ";
443: my $encrequest='';
444: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
445: $encrequest.=
446: unpack("H16",$cipher->encrypt(substr($rcmd,$encidx,8)));
447: }
448: $cmd="enc:$cmdlength:$encrequest\n";
449: }
450: $SIG{ALRM}=sub { die "timeout" };
451: $SIG{__DIE__}='DEFAULT';
452: eval {
453: alarm(60);
454: print $remotesock "$cmd\n";
455: $answer=<$remotesock>;
456: chomp($answer);
457: alarm(0);
458: };
459: $SIG{ALRM}='DEFAULT';
460: $SIG{__DIE__}=\&catchexception;
461:
462: if (($answer ne '') && ($@!~/timeout/)) {
463: unlink("$dfname");
464: &logthis("Delayed $cmd to $conserver: >$answer<");
465: &logperm("S:$conserver:$bcmd");
466: }
467: } @allbuffered;
468:
469: # ------------------------------------------------------- Listen to UNIX socket
470: &status("Opening socket $conserver");
471: unless (
472: $server = IO::Socket::UNIX->new(Local => $port,
473: Type => SOCK_STREAM,
474: Listen => 10 )
475: ) {
476: my $st=120+int(rand(240));
477: &logthis(
478: "<font color=blue>WARNING: ".
479: "Can't make server socket $conserver ($st secs): $@</font>");
480: sleep($st);
481: exit;
482: };
483:
484: # -----------------------------------------------------------------------------
485:
486: &logthis("<font color=green>$conserver online</font>");
487:
488: # -----------------------------------------------------------------------------
489: # begin with empty buffers
490: %inbuffer = ();
491: %outbuffer = ();
492: %ready = ();
493:
494: tie %ready, 'Tie::RefHash';
495:
496: nonblock($server);
497: $select = IO::Select->new($server);
498:
499: # Main loop: check reads/accepts, check writes, check ready to process
500: while (1) {
501: my $client;
502: my $rv;
503: my $data;
504:
505: # check for new information on the connections we have
506:
507: # anything to read or accept?
508: foreach $client ($select->can_read(0.1)) {
509:
510: if ($client == $server) {
511: # accept a new connection
512: &status("Accept new connection: $conserver");
513: $client = $server->accept();
514: $select->add($client);
515: nonblock($client);
516: } else {
517: # read data
518: $data = '';
519: $rv = $client->recv($data, POSIX::BUFSIZ, 0);
520:
521: unless (defined($rv) && length $data) {
522: # This would be the end of file, so close the client
523: delete $inbuffer{$client};
524: delete $outbuffer{$client};
525: delete $ready{$client};
526:
527: &status("Idle $conserver");
528: $select->remove($client);
529: close $client;
530: next;
531: }
532:
533: $inbuffer{$client} .= $data;
534:
535: # test whether the data in the buffer or the data we
536: # just read means there is a complete request waiting
537: # to be fulfilled. If there is, set $ready{$client}
538: # to the requests waiting to be fulfilled.
539: while ($inbuffer{$client} =~ s/(.*\n)//) {
540: push( @{$ready{$client}}, $1 );
541: }
542: }
543: }
544:
545: # Any complete requests to process?
546: foreach $client (keys %ready) {
547: handle($client);
548: }
549:
550: # Buffers to flush?
551: foreach $client ($select->can_write(1)) {
552: # Skip this client if we have nothing to say
553: next unless exists $outbuffer{$client};
554:
555: $rv = $client->send($outbuffer{$client}, 0);
556: unless (defined $rv) {
557: # Whine, but move on.
558: &logthis("I was told I could write, but I can't.\n");
559: next;
560: }
561: $errno=$!;
562: if (($rv == length $outbuffer{$client}) ||
563: ($errno == POSIX::EWOULDBLOCK) || ($errno == 0)) {
564: substr($outbuffer{$client}, 0, $rv) = '';
565: delete $outbuffer{$client} unless length $outbuffer{$client};
566: } else {
567: # Couldn't write all the data, and it wasn't because
568: # it would have blocked. Shutdown and move on.
569:
570: &logthis("Dropping data with ".$errno.": ".
571: length($outbuffer{$client}).", $rv");
572:
573: delete $inbuffer{$client};
574: delete $outbuffer{$client};
575: delete $ready{$client};
576:
577: $select->remove($client);
578: close($client);
579: next;
580: }
581: }
582: }
583: }
584:
585: # ------------------------------------------------------- End of make_new_child
586:
587: # handle($socket) deals with all pending requests for $client
588: sub handle {
589: # requests are in $ready{$client}
590: # send output to $outbuffer{$client}
591: my $client = shift;
592: my $request;
593:
594: foreach $request (@{$ready{$client}}) {
595: # ============================================================= Process request
596: # $request is the text of the request
597: # put text of reply into $outbuffer{$client}
598: # -----------------------------------------------------------------------------
599: if ($request =~ /^encrypt\:/) {
600: my $cmd=$request;
601: $cmd =~ s/^encrypt\://;
602: chomp($cmd);
603: my $cmdlength=length($cmd);
604: $cmd.=" ";
605: my $encrequest='';
606: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
607: $encrequest.=
608: unpack("H16",$cipher->encrypt(substr($cmd,$encidx,8)));
609: }
610: $request="enc:$cmdlength:$encrequest\n";
611: }
612: # --------------------------------------------------------------- Main exchange
613: $SIG{ALRM}=sub { die "timeout" };
614: $SIG{__DIE__}='DEFAULT';
615: eval {
616: alarm(300);
617: &status("Sending $conserver: $request");
618: print $remotesock "$request";
619: &status("Waiting for reply from $conserver: $request");
620: $answer=<$remotesock>;
621: &status("Received reply: $request");
622: alarm(0);
623: };
624: if ($@=~/timeout/) {
625: $answer='';
626: &logthis(
627: "<font color=red>CRITICAL: Timeout $conserver: $request</font>");
628: }
629: $SIG{ALRM}='DEFAULT';
630: $SIG{__DIE__}=\&catchexception;
631:
632:
633: if ($answer) {
634: if ($answer =~ /^enc/) {
635: my ($cmd,$cmdlength,$encinput)=split(/:/,$answer);
636: chomp($encinput);
637: $answer='';
638: for (my $encidx=0;$encidx<length($encinput);$encidx+=16) {
639: $answer.=$cipher->decrypt(
640: pack("H16",substr($encinput,$encidx,16))
641: );
642: }
643: $answer=substr($answer,0,$cmdlength);
644: $answer.="\n";
645: }
646: $outbuffer{$client} .= $answer;
647: } else {
648: $outbuffer{$client} .= "con_lost\n";
649: }
650:
651: # ===================================================== Done processing request
652: }
653: delete $ready{$client};
654: &status("Completed $conserver: $request");
655: # -------------------------------------------------------------- End non-forker
656: }
657: # ---------------------------------------------------------- End make_new_child
658: }
659:
660: # nonblock($socket) puts socket into nonblocking mode
661: sub nonblock {
662: my $socket = shift;
663: my $flags;
664:
665:
666: $flags = fcntl($socket, F_GETFL, 0)
667: or die "Can't get flags for socket: $!\n";
668: fcntl($socket, F_SETFL, $flags | O_NONBLOCK)
669: or die "Can't make socket nonblocking: $!\n";
670: }
671:
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