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 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: $SIG{ALRM}=sub { die "timeout" };
186: $SIG{__DIE__}='DEFAULT';
187: eval {
188: alarm(10);
189: print $sclient "$cmd\n";
190: my $answer=<$sclient>;
191: chomp($answer);
192: alarm(0);
193: };
194: if ((!$answer) || ($@=~/timeout/)) { $answer="con_lost"; }
195: $SIG{ALRM}='DEFAULT';
196: $SIG{__DIE__}=\&catchexception;
197: } else { $answer='self_reply'; }
198: return $answer;
199: }
200:
201: # --------------------------------------------------------------------- Logging
202:
203: sub logthis {
204: my $message=shift;
205: my $execdir=$perlvar{'lonDaemons'};
206: my $fh=IO::File->new(">>$execdir/logs/lonc.log");
207: my $now=time;
208: my $local=localtime($now);
209: $lastlog=$local.': '.$message;
210: print $fh "$local ($$): $message\n";
211: }
212:
213:
214: sub logperm {
215: my $message=shift;
216: my $execdir=$perlvar{'lonDaemons'};
217: my $now=time;
218: my $local=localtime($now);
219: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
220: print $fh "$now:$message:$local\n";
221: }
222: # ------------------------------------------------------------------ Log status
223:
224: sub logstatus {
225: my $docdir=$perlvar{'lonDocRoot'};
226: my $fh=IO::File->new(">>$docdir/lon-status/loncstatus.txt");
227: print $fh $$."\t".$status."\t".$lastlog."\n";
228: }
229:
230: sub initnewstatus {
231: my $docdir=$perlvar{'lonDocRoot'};
232: my $fh=IO::File->new(">$docdir/lon-status/loncstatus.txt");
233: my $now=time;
234: my $local=localtime($now);
235: print $fh "LONC status $local - parent $$\n\n";
236: }
237:
238: # -------------------------------------------------------------- Status setting
239:
240: sub status {
241: my $what=shift;
242: my $now=time;
243: my $local=localtime($now);
244: $status=$local.': '.$what;
245: }
246:
247:
248: # ---------------------------------------------------- Fork once and dissociate
249:
250: $fpid=fork;
251: exit if $fpid;
252: die "Couldn't fork: $!" unless defined ($fpid);
253:
254: POSIX::setsid() or die "Can't start new session: $!";
255:
256: # ------------------------------------------------------- Write our PID on disk
257:
258: $execdir=$perlvar{'lonDaemons'};
259: open (PIDSAVE,">$execdir/logs/lonc.pid");
260: print PIDSAVE "$$\n";
261: close(PIDSAVE);
262: &logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
263:
264: # ----------------------------- Ignore signals generated during initial startup
265: $SIG{HUP}=$SIG{USR1}='IGNORE';
266: # ------------------------------------------------------- Now we are on our own
267:
268: # Fork off our children, one for every server
269:
270: &status("Forking ...");
271:
272: foreach $thisserver (keys %hostip) {
273: make_new_child($thisserver);
274: }
275:
276: &logthis("Done starting initial servers");
277: # ----------------------------------------------------- Install signal handlers
278:
279: $SIG{CHLD} = \&REAPER;
280: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
281: $SIG{HUP} = \&HUPSMAN;
282: $SIG{USR1} = \&USRMAN;
283:
284: # And maintain the population.
285: while (1) {
286: &status("Sleeping");
287: sleep; # wait for a signal (i.e., child's death)
288: # See who died and start new one
289: &status("Woke up");
290: foreach $thisserver (keys %hostip) {
291: if (!$childpid{$thisserver}) {
292: if ($childatt{$thisserver}<$childmaxattempts) {
293: $childatt{$thisserver}++;
294: &logthis(
295: "<font color=yellow>INFO: Trying to reconnect for $thisserver "
296: ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
297: make_new_child($thisserver);
298: }
299: }
300: }
301: }
302:
303:
304: sub make_new_child {
305:
306: my $conserver=shift;
307: my $pid;
308: my $sigset;
309: &logthis("Attempting to start child for server $conserver");
310: # block signal for fork
311: $sigset = POSIX::SigSet->new(SIGINT);
312: sigprocmask(SIG_BLOCK, $sigset)
313: or die "Can't block SIGINT for fork: $!\n";
314:
315: die "fork: $!" unless defined ($pid = fork);
316:
317: if ($pid) {
318: # Parent records the child's birth and returns.
319: sigprocmask(SIG_UNBLOCK, $sigset)
320: or die "Can't unblock SIGINT for fork: $!\n";
321: $children{$pid} = $conserver;
322: $childpid{$conserver} = $pid;
323: return;
324: } else {
325: # Child can *not* return from this subroutine.
326: $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
327: $SIG{USR1}= \&logstatus;
328:
329: # unblock signals
330: sigprocmask(SIG_UNBLOCK, $sigset)
331: or die "Can't unblock SIGINT for fork: $!\n";
332:
333: # ----------------------------- This is the modified main program of non-forker
334:
335: $port = "$perlvar{'lonSockDir'}/$conserver";
336:
337: unlink($port);
338:
339: # ---------------------------------------------------- Client to network server
340:
341: &status("Opening TCP: $conserver");
342:
343: unless (
344: $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
345: PeerPort => $perlvar{'londPort'},
346: Proto => "tcp",
347: Type => SOCK_STREAM)
348: ) {
349: my $st=120+int(rand(240));
350: &logthis(
351: "<font color=blue>WARNING: Couldn't connect $conserver ($st secs): $@</font>");
352: sleep($st);
353: exit;
354: };
355: # --------------------------------------- Send a ping to make other end do USR1
356:
357: &status("Init dialogue: $conserver");
358:
359: print $remotesock "init\n";
360: $answer=<$remotesock>;
361: print $remotesock "$answer";
362: $answer=<$remotesock>;
363: chomp($answer);
364: &logthis("Init reply for $conserver: >$answer<");
365: if ($answer ne 'ok') {
366: my $st=120+int(rand(240));
367: &logthis(
368: "<font color=blue>WARNING: Init failed $conserver ($st secs)</font>");
369: sleep($st);
370: exit;
371: }
372: sleep 5;
373: &status("Ponging $conserver");
374: print $remotesock "pong\n";
375: $answer=<$remotesock>;
376: chomp($answer);
377: &logthis("Pong reply for $conserver: >$answer<");
378: # ----------------------------------------------------------- Initialize cipher
379:
380: &status("Initialize cipher: $conserver");
381: print $remotesock "ekey\n";
382: my $buildkey=<$remotesock>;
383: my $key=$conserver.$perlvar{'lonHostID'};
384: $key=~tr/a-z/A-Z/;
385: $key=~tr/G-P/0-9/;
386: $key=~tr/Q-Z/0-9/;
387: $key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
388: $key=substr($key,0,32);
389: my $cipherkey=pack("H32",$key);
390: if ($cipher=new IDEA $cipherkey) {
391: &logthis("Secure connection initialized: $conserver");
392: } else {
393: my $st=120+int(rand(240));
394: &logthis(
395: "<font color=blue>WARNING: ".
396: "Could not establish secure connection, $conserver ($st secs)!</font>");
397: sleep($st);
398: exit;
399: }
400:
401: # ----------------------------------------- We're online, send delayed messages
402: &status("Checking for delayed messages");
403: my @allbuffered;
404: my $path="$perlvar{'lonSockDir'}/delayed";
405: opendir(DIRHANDLE,$path);
406: @allbuffered=grep /\.$conserver$/, readdir DIRHANDLE;
407: closedir(DIRHANDLE);
408: my $dfname;
409: map {
410: &status("Sending delayed $conserver $_");
411: $dfname="$path/$_";
412: &logthis($dfname);
413: my $wcmd;
414: {
415: my $dfh=IO::File->new($dfname);
416: $cmd=<$dfh>;
417: }
418: chomp($cmd);
419: my $bcmd=$cmd;
420: if ($cmd =~ /^encrypt\:/) {
421: my $rcmd=$cmd;
422: $rcmd =~ s/^encrypt\://;
423: chomp($rcmd);
424: my $cmdlength=length($rcmd);
425: $rcmd.=" ";
426: my $encrequest='';
427: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
428: $encrequest.=
429: unpack("H16",$cipher->encrypt(substr($rcmd,$encidx,8)));
430: }
431: $cmd="enc:$cmdlength:$encrequest\n";
432: }
433:
434: print $remotesock "$cmd\n";
435: $answer=<$remotesock>;
436: chomp($answer);
437: if ($answer ne '') {
438: unlink("$dfname");
439: &logthis("Delayed $cmd to $conserver: >$answer<");
440: &logperm("S:$conserver:$bcmd");
441: }
442: } @allbuffered;
443:
444: # ------------------------------------------------------- Listen to UNIX socket
445: &status("Opening socket $conserver");
446: unless (
447: $server = IO::Socket::UNIX->new(Local => $port,
448: Type => SOCK_STREAM,
449: Listen => 10 )
450: ) {
451: my $st=120+int(rand(240));
452: &logthis(
453: "<font color=blue>WARNING: ".
454: "Can't make server socket $conserver ($st secs): $@</font>");
455: sleep($st);
456: exit;
457: };
458:
459: # -----------------------------------------------------------------------------
460:
461: &logthis("<font color=green>$conserver online</font>");
462:
463: # -----------------------------------------------------------------------------
464: # begin with empty buffers
465: %inbuffer = ();
466: %outbuffer = ();
467: %ready = ();
468:
469: tie %ready, 'Tie::RefHash';
470:
471: nonblock($server);
472: $select = IO::Select->new($server);
473:
474: # Main loop: check reads/accepts, check writes, check ready to process
475: while (1) {
476: my $client;
477: my $rv;
478: my $data;
479:
480: # check for new information on the connections we have
481:
482: # anything to read or accept?
483: foreach $client ($select->can_read(0.1)) {
484:
485: if ($client == $server) {
486: # accept a new connection
487: &status("Accept new connection: $conserver");
488: $client = $server->accept();
489: $select->add($client);
490: nonblock($client);
491: } else {
492: # read data
493: $data = '';
494: $rv = $client->recv($data, POSIX::BUFSIZ, 0);
495:
496: unless (defined($rv) && length $data) {
497: # This would be the end of file, so close the client
498: delete $inbuffer{$client};
499: delete $outbuffer{$client};
500: delete $ready{$client};
501:
502: &status("Idle $conserver");
503: $select->remove($client);
504: close $client;
505: next;
506: }
507:
508: $inbuffer{$client} .= $data;
509:
510: # test whether the data in the buffer or the data we
511: # just read means there is a complete request waiting
512: # to be fulfilled. If there is, set $ready{$client}
513: # to the requests waiting to be fulfilled.
514: while ($inbuffer{$client} =~ s/(.*\n)//) {
515: push( @{$ready{$client}}, $1 );
516: }
517: }
518: }
519:
520: # Any complete requests to process?
521: foreach $client (keys %ready) {
522: handle($client);
523: }
524:
525: # Buffers to flush?
526: foreach $client ($select->can_write(1)) {
527: # Skip this client if we have nothing to say
528: next unless exists $outbuffer{$client};
529:
530: $rv = $client->send($outbuffer{$client}, 0);
531: unless (defined $rv) {
532: # Whine, but move on.
533: &logthis("I was told I could write, but I can't.\n");
534: next;
535: }
536: $errno=$!;
537: if (($rv == length $outbuffer{$client}) ||
538: ($errno == POSIX::EWOULDBLOCK) || ($errno == 0)) {
539: substr($outbuffer{$client}, 0, $rv) = '';
540: delete $outbuffer{$client} unless length $outbuffer{$client};
541: } else {
542: # Couldn't write all the data, and it wasn't because
543: # it would have blocked. Shutdown and move on.
544:
545: &logthis("Dropping data with ".$errno.": ".
546: length($outbuffer{$client}).", $rv");
547:
548: delete $inbuffer{$client};
549: delete $outbuffer{$client};
550: delete $ready{$client};
551:
552: $select->remove($client);
553: close($client);
554: next;
555: }
556: }
557: }
558: }
559:
560: # ------------------------------------------------------- End of make_new_child
561:
562: # handle($socket) deals with all pending requests for $client
563: sub handle {
564: # requests are in $ready{$client}
565: # send output to $outbuffer{$client}
566: my $client = shift;
567: my $request;
568:
569: foreach $request (@{$ready{$client}}) {
570: # ============================================================= Process request
571: # $request is the text of the request
572: # put text of reply into $outbuffer{$client}
573: # -----------------------------------------------------------------------------
574: if ($request =~ /^encrypt\:/) {
575: my $cmd=$request;
576: $cmd =~ s/^encrypt\://;
577: chomp($cmd);
578: my $cmdlength=length($cmd);
579: $cmd.=" ";
580: my $encrequest='';
581: for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
582: $encrequest.=
583: unpack("H16",$cipher->encrypt(substr($cmd,$encidx,8)));
584: }
585: $request="enc:$cmdlength:$encrequest\n";
586: }
587: # --------------------------------------------------------------- Main exchange
588: $SIG{ALRM}=sub { die "timeout" };
589: $SIG{__DIE__}='DEFAULT';
590: eval {
591: alarm(300);
592: &status("Sending $conserver: $request");
593: print $remotesock "$request";
594: &status("Waiting for reply from $conserver: $request");
595: $answer=<$remotesock>;
596: &status("Received reply: $request");
597: alarm(0);
598: };
599: if ($@=~/timeout/) {
600: $answer='';
601: &logthis(
602: "<font color=red>CRITICAL: Timeout $conserver: $request</font>");
603: }
604: $SIG{ALRM}='DEFAULT';
605: $SIG{__DIE__}=\&catchexception;
606:
607:
608: if ($answer) {
609: if ($answer =~ /^enc/) {
610: my ($cmd,$cmdlength,$encinput)=split(/:/,$answer);
611: chomp($encinput);
612: $answer='';
613: for (my $encidx=0;$encidx<length($encinput);$encidx+=16) {
614: $answer.=$cipher->decrypt(
615: pack("H16",substr($encinput,$encidx,16))
616: );
617: }
618: $answer=substr($answer,0,$cmdlength);
619: $answer.="\n";
620: }
621: $outbuffer{$client} .= $answer;
622: } else {
623: $outbuffer{$client} .= "con_lost\n";
624: }
625:
626: # ===================================================== Done processing request
627: }
628: delete $ready{$client};
629: &status("Completed $conserver: $request");
630: # -------------------------------------------------------------- End non-forker
631: }
632: # ---------------------------------------------------------- End make_new_child
633: }
634:
635: # nonblock($socket) puts socket into nonblocking mode
636: sub nonblock {
637: my $socket = shift;
638: my $flags;
639:
640:
641: $flags = fcntl($socket, F_GETFL, 0)
642: or die "Can't get flags for socket: $!\n";
643: fcntl($socket, F_SETFL, $flags | O_NONBLOCK)
644: or die "Can't make socket nonblocking: $!\n";
645: }
646:
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