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