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 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: print $sclient "$cmd\n";
186: my $answer=<$sclient>;
187: chomp($answer);
188: if (!$answer) { $answer="con_lost"; }
189: } else { $answer='self_reply'; }
190: return $answer;
191: }
192:
193: # --------------------------------------------------------------------- Logging
194:
195: sub logthis {
196: my $message=shift;
197: my $execdir=$perlvar{'lonDaemons'};
198: my $fh=IO::File->new(">>$execdir/logs/lonc.log");
199: my $now=time;
200: my $local=localtime($now);
201: $lastlog=$local.': '.$message;
202: print $fh "$local ($$): $message\n";
203: }
204:
205:
206: sub logperm {
207: my $message=shift;
208: my $execdir=$perlvar{'lonDaemons'};
209: my $now=time;
210: my $local=localtime($now);
211: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
212: print $fh "$now:$message:$local\n";
213: }
214: # ------------------------------------------------------------------ Log status
215:
216: sub logstatus {
217: my $docdir=$perlvar{'lonDocRoot'};
218: my $fh=IO::File->new(">>$docdir/lon-status/loncstatus.txt");
219: print $fh $$."\t".$status."\t".$lastlog."\n";
220: }
221:
222: sub initnewstatus {
223: my $docdir=$perlvar{'lonDocRoot'};
224: my $fh=IO::File->new(">$docdir/lon-status/loncstatus.txt");
225: my $now=time;
226: my $local=localtime($now);
227: print $fh "LONC status $local - parent $$\n\n";
228: }
229:
230: # -------------------------------------------------------------- Status setting
231:
232: sub status {
233: my $what=shift;
234: my $now=time;
235: my $local=localtime($now);
236: $status=$local.': '.$what;
237: }
238:
239:
240: # ---------------------------------------------------- Fork once and dissociate
241:
242: $fpid=fork;
243: exit if $fpid;
244: die "Couldn't fork: $!" unless defined ($fpid);
245:
246: POSIX::setsid() or die "Can't start new session: $!";
247:
248: # ------------------------------------------------------- Write our PID on disk
249:
250: $execdir=$perlvar{'lonDaemons'};
251: open (PIDSAVE,">$execdir/logs/lonc.pid");
252: print PIDSAVE "$$\n";
253: close(PIDSAVE);
254: &logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
255:
256: # ----------------------------- Ignore signals generated during initial startup
257: $SIG{HUP}=$SIG{USR1}='IGNORE';
258: # ------------------------------------------------------- Now we are on our own
259:
260: # Fork off our children, one for every server
261:
262: &status("Forking ...");
263:
264: foreach $thisserver (keys %hostip) {
265: make_new_child($thisserver);
266: }
267:
268: &logthis("Done starting initial servers");
269: # ----------------------------------------------------- Install signal handlers
270:
271: $SIG{CHLD} = \&REAPER;
272: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
273: $SIG{HUP} = \&HUPSMAN;
274: $SIG{USR1} = \&USRMAN;
275:
276: # And maintain the population.
277: while (1) {
278: &status("Sleeping");
279: sleep; # wait for a signal (i.e., child's death)
280: # See who died and start new one
281: &status("Woke up");
282: foreach $thisserver (keys %hostip) {
283: if (!$childpid{$thisserver}) {
284: if ($childatt{$thisserver}<$childmaxattempts) {
285: $childatt{$thisserver}++;
286: &logthis(
287: "<font color=yellow>INFO: Trying to reconnect for $thisserver "
288: ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
289: make_new_child($thisserver);
290: }
291: }
292: }
293: }
294:
295:
296: sub make_new_child {
297:
298: my $conserver=shift;
299: my $pid;
300: my $sigset;
301: &logthis("Attempting to start child for server $conserver");
302: # block signal for fork
303: $sigset = POSIX::SigSet->new(SIGINT);
304: sigprocmask(SIG_BLOCK, $sigset)
305: or die "Can't block SIGINT for fork: $!\n";
306:
307: die "fork: $!" unless defined ($pid = fork);
308:
309: if ($pid) {
310: # Parent records the child's birth and returns.
311: sigprocmask(SIG_UNBLOCK, $sigset)
312: or die "Can't unblock SIGINT for fork: $!\n";
313: $children{$pid} = $conserver;
314: $childpid{$conserver} = $pid;
315: return;
316: } else {
317: # Child can *not* return from this subroutine.
318: $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
319: $SIG{USR1}= \&logstatus;
320:
321: # unblock signals
322: sigprocmask(SIG_UNBLOCK, $sigset)
323: or die "Can't unblock SIGINT for fork: $!\n";
324:
325: # ----------------------------- This is the modified main program of non-forker
326:
327: $port = "$perlvar{'lonSockDir'}/$conserver";
328:
329: unlink($port);
330:
331: # ---------------------------------------------------- Client to network server
332:
333: &status("Opening TCP: $conserver");
334:
335: unless (
336: $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
337: PeerPort => $perlvar{'londPort'},
338: Proto => "tcp",
339: Type => SOCK_STREAM)
340: ) {
341: my $st=120+int(rand(240));
342: &logthis(
343: "<font color=blue>WARNING: Couldn't connect $conserver ($st secs): $@</font>");
344: sleep($st);
345: exit;
346: };
347: # --------------------------------------- Send a ping to make other end do USR1
348:
349: &status("Init dialogue: $conserver");
350:
351: print $remotesock "init\n";
352: $answer=<$remotesock>;
353: print $remotesock "$answer";
354: $answer=<$remotesock>;
355: chomp($answer);
356: &logthis("Init reply for $conserver: >$answer<");
357: if ($answer ne 'ok') {
358: my $st=120+int(rand(240));
359: &logthis(
360: "<font color=blue>WARNING: Init failed $conserver ($st secs)</font>");
361: sleep($st);
362: exit;
363: }
364: sleep 5;
365: &status("Ponging $conserver");
366: print $remotesock "pong\n";
367: $answer=<$remotesock>;
368: chomp($answer);
369: &logthis("Pong reply for $conserver: >$answer<");
370: # ----------------------------------------------------------- Initialize cipher
371:
372: &status("Initialize cipher: $conserver");
373: print $remotesock "ekey\n";
374: my $buildkey=<$remotesock>;
375: my $key=$conserver.$perlvar{'lonHostID'};
376: $key=~tr/a-z/A-Z/;
377: $key=~tr/G-P/0-9/;
378: $key=~tr/Q-Z/0-9/;
379: $key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
380: $key=substr($key,0,32);
381: my $cipherkey=pack("H32",$key);
382: if ($cipher=new IDEA $cipherkey) {
383: &logthis("Secure connection initialized: $conserver");
384: } else {
385: my $st=120+int(rand(240));
386: &logthis(
387: "<font color=blue>WARNING: ".
388: "Could not establish secure connection, $conserver ($st secs)!</font>");
389: sleep($st);
390: exit;
391: }
392:
393: # ----------------------------------------- We're online, send delayed messages
394: &status("Checking for delayed messages");
395: my @allbuffered;
396: my $path="$perlvar{'lonSockDir'}/delayed";
397: opendir(DIRHANDLE,$path);
398: @allbuffered=grep /\.$conserver$/, readdir DIRHANDLE;
399: closedir(DIRHANDLE);
400: my $dfname;
401: map {
402: &status("Sending delayed $conserver $_");
403: $dfname="$path/$_";
404: &logthis($dfname);
405: my $wcmd;
406: {
407: my $dfh=IO::File->new($dfname);
408: $cmd=<$dfh>;
409: }
410: chomp($cmd);
411: my $bcmd=$cmd;
412: if ($cmd =~ /^encrypt\:/) {
413: my $rcmd=$cmd;
414: $rcmd =~ s/^encrypt\://;
415: chomp($rcmd);
416: my $cmdlength=length($rcmd);
417: $rcmd.=" ";
418: my $encrequest='';
419: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
420: $encrequest.=
421: unpack("H16",$cipher->encrypt(substr($rcmd,$encidx,8)));
422: }
423: $cmd="enc:$cmdlength:$encrequest\n";
424: }
425:
426: print $remotesock "$cmd\n";
427: $answer=<$remotesock>;
428: chomp($answer);
429: if ($answer ne '') {
430: unlink("$dfname");
431: &logthis("Delayed $cmd to $conserver: >$answer<");
432: &logperm("S:$conserver:$bcmd");
433: }
434: } @allbuffered;
435:
436: # ------------------------------------------------------- Listen to UNIX socket
437: &status("Opening socket $conserver");
438: unless (
439: $server = IO::Socket::UNIX->new(Local => $port,
440: Type => SOCK_STREAM,
441: Listen => 10 )
442: ) {
443: my $st=120+int(rand(240));
444: &logthis(
445: "<font color=blue>WARNING: ".
446: "Can't make server socket $conserver ($st secs): $@</font>");
447: sleep($st);
448: exit;
449: };
450:
451: # -----------------------------------------------------------------------------
452:
453: &logthis("<font color=green>$conserver online</font>");
454:
455: # -----------------------------------------------------------------------------
456: # begin with empty buffers
457: %inbuffer = ();
458: %outbuffer = ();
459: %ready = ();
460:
461: tie %ready, 'Tie::RefHash';
462:
463: nonblock($server);
464: $select = IO::Select->new($server);
465:
466: # Main loop: check reads/accepts, check writes, check ready to process
467: while (1) {
468: my $client;
469: my $rv;
470: my $data;
471:
472: # check for new information on the connections we have
473:
474: # anything to read or accept?
475: foreach $client ($select->can_read(0.1)) {
476:
477: if ($client == $server) {
478: # accept a new connection
479: &status("Accept new connection: $conserver");
480: $client = $server->accept();
481: $select->add($client);
482: nonblock($client);
483: } else {
484: # read data
485: $data = '';
486: $rv = $client->recv($data, POSIX::BUFSIZ, 0);
487:
488: unless (defined($rv) && length $data) {
489: # This would be the end of file, so close the client
490: delete $inbuffer{$client};
491: delete $outbuffer{$client};
492: delete $ready{$client};
493:
494: &status("Idle $conserver");
495: $select->remove($client);
496: close $client;
497: next;
498: }
499:
500: $inbuffer{$client} .= $data;
501:
502: # test whether the data in the buffer or the data we
503: # just read means there is a complete request waiting
504: # to be fulfilled. If there is, set $ready{$client}
505: # to the requests waiting to be fulfilled.
506: while ($inbuffer{$client} =~ s/(.*\n)//) {
507: push( @{$ready{$client}}, $1 );
508: }
509: }
510: }
511:
512: # Any complete requests to process?
513: foreach $client (keys %ready) {
514: handle($client);
515: }
516:
517: # Buffers to flush?
518: foreach $client ($select->can_write(1)) {
519: # Skip this client if we have nothing to say
520: next unless exists $outbuffer{$client};
521:
522: $rv = $client->send($outbuffer{$client}, 0);
523: unless (defined $rv) {
524: # Whine, but move on.
525: &logthis("I was told I could write, but I can't.\n");
526: next;
527: }
528: $errno=$!;
529: if (($rv == length $outbuffer{$client}) ||
530: ($errno == POSIX::EWOULDBLOCK) || ($errno == 0)) {
531: substr($outbuffer{$client}, 0, $rv) = '';
532: delete $outbuffer{$client} unless length $outbuffer{$client};
533: } else {
534: # Couldn't write all the data, and it wasn't because
535: # it would have blocked. Shutdown and move on.
536:
537: &logthis("Dropping data with ".$errno.": ".
538: length($outbuffer{$client}).", $rv");
539:
540: delete $inbuffer{$client};
541: delete $outbuffer{$client};
542: delete $ready{$client};
543:
544: $select->remove($client);
545: close($client);
546: next;
547: }
548: }
549: }
550: }
551:
552: # ------------------------------------------------------- End of make_new_child
553:
554: # handle($socket) deals with all pending requests for $client
555: sub handle {
556: # requests are in $ready{$client}
557: # send output to $outbuffer{$client}
558: my $client = shift;
559: my $request;
560:
561: foreach $request (@{$ready{$client}}) {
562: # ============================================================= Process request
563: # $request is the text of the request
564: # put text of reply into $outbuffer{$client}
565: # -----------------------------------------------------------------------------
566: if ($request =~ /^encrypt\:/) {
567: my $cmd=$request;
568: $cmd =~ s/^encrypt\://;
569: chomp($cmd);
570: my $cmdlength=length($cmd);
571: $cmd.=" ";
572: my $encrequest='';
573: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
574: $encrequest.=
575: unpack("H16",$cipher->encrypt(substr($cmd,$encidx,8)));
576: }
577: $request="enc:$cmdlength:$encrequest\n";
578: }
579: &status("Sending $conserver: $request");
580: print $remotesock "$request";
581: &status("Waiting for reply from $conserver: $request");
582: $answer=<$remotesock>;
583: &status("Received reply: $request");
584: if ($answer) {
585: if ($answer =~ /^enc/) {
586: my ($cmd,$cmdlength,$encinput)=split(/:/,$answer);
587: chomp($encinput);
588: $answer='';
589: for (my $encidx=0;$encidx<length($encinput);$encidx+=16) {
590: $answer.=$cipher->decrypt(
591: pack("H16",substr($encinput,$encidx,16))
592: );
593: }
594: $answer=substr($answer,0,$cmdlength);
595: $answer.="\n";
596: }
597: $outbuffer{$client} .= $answer;
598: } else {
599: $outbuffer{$client} .= "con_lost\n";
600: }
601:
602: # ===================================================== Done processing request
603: }
604: delete $ready{$client};
605: &status("Completed $conserver: $request");
606: # -------------------------------------------------------------- End non-forker
607: }
608: # ---------------------------------------------------------- End make_new_child
609: }
610:
611: # nonblock($socket) puts socket into nonblocking mode
612: sub nonblock {
613: my $socket = shift;
614: my $flags;
615:
616:
617: $flags = fcntl($socket, F_GETFL, 0)
618: or die "Can't get flags for socket: $!\n";
619: fcntl($socket, F_SETFL, $flags | O_NONBLOCK)
620: or die "Can't make socket nonblocking: $!\n";
621: }
622:
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