--- loncom/Attic/lonc 2001/03/15 20:25:20 1.15
+++ loncom/Attic/lonc 2002/03/20 03:44:11 1.34
@@ -5,6 +5,30 @@
# provides persistent TCP connections to the other servers in the network
# through multiplexed domain sockets
#
+# $Id: lonc,v 1.34 2002/03/20 03:44:11 foxr Exp $
+#
+# Copyright Michigan State University Board of Trustees
+#
+# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
+#
+# LON-CAPA is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# LON-CAPA is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with LON-CAPA; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+#
+# /home/httpd/html/adm/gpl.txt
+#
+# http://www.lon-capa.org/
+#
# PID in subdir logs/lonc.pid
# kill kills
# HUP restarts
@@ -15,9 +39,13 @@
# 2/8,7/25 Gerd Kortemeyer
# 12/05 Scott Harrison
# 12/05 Gerd Kortemeyer
+# YEAR=2001
# 01/10/01 Scott Harrison
-# 03/14/01,03/15 Gerd Kortemeyer
-#
+# 03/14/01,03/15,06/12,11/26,11/27,11/28 Gerd Kortemeyer
+# 12/20 Scott Harrison
+# YEAR=2002
+# 2/19/02,02/22/02,02/25/02 Gerd Kortemeyer
+# 3/07/02 Ron Fox
# based on nonforker from Perl Cookbook
# - server who multiplexes without forking
@@ -29,27 +57,22 @@ use Socket;
use Fcntl;
use Tie::RefHash;
use Crypt::IDEA;
+#use Net::Ping;
+use LWP::UserAgent();
-# grabs exception and records it to log before exiting
-sub catchexception {
- my ($signal)=@_;
- $SIG{'QUIT'}='DEFAULT';
- $SIG{__DIE__}='DEFAULT';
- &logthis("<font color=red>CRITICAL: "
- ."ABNORMAL EXIT. Child $$ for server $wasserver died through "
- ."\"$signal\" with this parameter->[$@]</font>");
- die($@);
-}
-
-$childmaxattempts=10;
+$status='';
+$lastlog='';
+$conserver='SHELL';
+$DEBUG = 0; # Set to 1 for annoyingly complete logs.
# -------------------------------- Set signal handlers to record abnormal exits
-$SIG{'QUIT'}=\&catchexception;
+&status("Init exception handlers");
+$SIG{QUIT}=\&catchexception;
$SIG{__DIE__}=\&catchexception;
# ------------------------------------ Read httpd access.conf and get variables
-
+&status("Read access.conf");
open (CONFIG,"/etc/httpd/conf/access.conf") || die "Can't read access.conf";
while ($configline=<CONFIG>) {
@@ -62,6 +85,7 @@ while ($configline=<CONFIG>) {
close(CONFIG);
# ----------------------------- Make sure this process is running from user=www
+&status("Check user ID");
my $wwwid=getpwnam('www');
if ($wwwid!=$<) {
$emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
@@ -89,8 +113,12 @@ open (CONFIG,"$perlvar{'lonTabDir'}/host
while ($configline=<CONFIG>) {
my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
chomp($ip);
- $hostip{$id}=$ip;
+ if ($ip) {
+ $hostip{$id}=$ip;
+ $hostname{$id}=$name;
+ }
}
+
close(CONFIG);
# -------------------------------------------------------- Routines for forking
@@ -102,96 +130,20 @@ close(CONFIG);
%childatt = (); # number of attempts to start server
# for ID
-sub REAPER { # takes care of dead children
- $SIG{CHLD} = \&REAPER;
- my $pid = wait;
- my $wasserver=$children{$pid};
- &logthis("<font color=red>CRITICAL: "
- ."Child $pid for server $wasserver died ($childatt{$wasserver})</font>");
- delete $children{$pid};
- delete $childpid{$wasserver};
- my $port = "$perlvar{'lonSockDir'}/$wasserver";
- unlink($port);
-}
-
-sub HUNTSMAN { # signal handler for SIGINT
- local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
- kill 'INT' => keys %children;
- my $execdir=$perlvar{'lonDaemons'};
- unlink("$execdir/logs/lonc.pid");
- &logthis("<font color=red>CRITICAL: Shutting down</font>");
- exit; # clean up with dignity
-}
-
-sub HUPSMAN { # signal handler for SIGHUP
- local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
- kill 'INT' => keys %children;
- &logthis("<font color=red>CRITICAL: Restarting</font>");
- unlink("$execdir/logs/lonc.pid");
- my $execdir=$perlvar{'lonDaemons'};
- exec("$execdir/lonc"); # here we go again
-}
-
-sub USRMAN {
- &logthis("USR1: Trying to establish connections again");
- foreach $thisserver (keys %hostip) {
- $answer=subreply("ping",$thisserver);
- &logthis("USR1: Ping $thisserver "
- ."(pid >$childpid{$thisserver}<, $childatt{thisserver} attempts): "
- ." >$answer<");
- }
- %childatt=();
-}
-
-# -------------------------------------------------- Non-critical communication
-sub subreply {
- my ($cmd,$server)=@_;
- my $answer='';
- if ($server ne $perlvar{'lonHostID'}) {
- my $peerfile="$perlvar{'lonSockDir'}/$server";
- my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
- Type => SOCK_STREAM,
- Timeout => 10)
- or return "con_lost";
- print $sclient "$cmd\n";
- my $answer=<$sclient>;
- chomp($answer);
- if (!$answer) { $answer="con_lost"; }
- } else { $answer='self_reply'; }
- return $answer;
-}
-
-# --------------------------------------------------------------------- Logging
-
-sub logthis {
- my $message=shift;
- my $execdir=$perlvar{'lonDaemons'};
- my $fh=IO::File->new(">>$execdir/logs/lonc.log");
- my $now=time;
- my $local=localtime($now);
- print $fh "$local ($$): $message\n";
-}
-
-
-sub logperm {
- my $message=shift;
- my $execdir=$perlvar{'lonDaemons'};
- my $now=time;
- my $local=localtime($now);
- my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
- print $fh "$now:$message:$local\n";
-}
+$childmaxattempts=5;
# ---------------------------------------------------- Fork once and dissociate
-
+&status("Fork and dissociate");
$fpid=fork;
exit if $fpid;
die "Couldn't fork: $!" unless defined ($fpid);
POSIX::setsid() or die "Can't start new session: $!";
-# ------------------------------------------------------- Write our PID on disk
+$conserver='PARENT';
+# ------------------------------------------------------- Write our PID on disk
+&status("Write PID");
$execdir=$perlvar{'lonDaemons'};
open (PIDSAVE,">$execdir/logs/lonc.pid");
print PIDSAVE "$$\n";
@@ -204,42 +156,62 @@ $SIG{HUP}=$SIG{USR1}='IGNORE';
# Fork off our children, one for every server
+&status("Forking ...");
+
foreach $thisserver (keys %hostip) {
- make_new_child($thisserver);
+ #if (&online($hostname{$thisserver})) {
+ make_new_child($thisserver);
+ #}
}
&logthis("Done starting initial servers");
# ----------------------------------------------------- Install signal handlers
-$SIG{CHLD} = \&REAPER;
+
$SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
$SIG{HUP} = \&HUPSMAN;
$SIG{USR1} = \&USRMAN;
# And maintain the population.
while (1) {
- sleep; # wait for a signal (i.e., child's death)
+ my $deadpid = wait; # Wait for the next child to die.
# See who died and start new one
- foreach $thisserver (keys %hostip) {
- if (!$childpid{$thisserver}) {
- if ($childatt{$thisserver}<=$childmaxattempts) {
- $childatt{$thisserver}++;
- &logthis(
- "<font color=yellow>INFO: Trying to reconnect for $thisserver "
- ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
- make_new_child($thisserver);
- }
- }
+ &status("Woke up");
+ my $skipping='';
+
+ if(exists($children{$deadpid})) {
+
+ $thisserver = $children{$deadpid}; # Look name of dead guy's peer.
+
+ delete($children{$deadpid}); # Get rid of dead hash entry.
+
+ if($childatt{$thisserver} < $childmaxattempts) {
+ $childatt{$thisserver}++;
+ &logthis(
+ "<font color=yellow>INFO: Trying to reconnect for $thisserver "
+ ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
+ make_new_child($thisserver);
+
+ }
+ else {
+ $skipping .= $thisserver.' ';
+ }
+ if($skipping) {
+ &logthis("<font color=blue>WARNING: Skipped $skipping</font>");
+
+ }
}
+
}
+
sub make_new_child {
- my $conserver=shift;
+ $newserver=shift;
my $pid;
my $sigset;
- &logthis("Attempting to start child for server $conserver");
+ &logthis("Attempting to start child for server $newserver");
# block signal for fork
$sigset = POSIX::SigSet->new(SIGINT);
sigprocmask(SIG_BLOCK, $sigset)
@@ -251,13 +223,15 @@ sub make_new_child {
# Parent records the child's birth and returns.
sigprocmask(SIG_UNBLOCK, $sigset)
or die "Can't unblock SIGINT for fork: $!\n";
- $children{$pid} = $conserver;
- $childpid{$conserver} = $pid;
+ $children{$pid} = $newserver;
+ $childpid{$newserver} = $pid;
return;
} else {
+ $conserver=$newserver;
# Child can *not* return from this subroutine.
$SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
-
+ $SIG{USR1}= \&logstatus;
+
# unblock signals
sigprocmask(SIG_UNBLOCK, $sigset)
or die "Can't unblock SIGINT for fork: $!\n";
@@ -267,54 +241,13 @@ sub make_new_child {
$port = "$perlvar{'lonSockDir'}/$conserver";
unlink($port);
-# ---------------------------------------------------- Client to network server
-unless (
- $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
- PeerPort => $perlvar{'londPort'},
- Proto => "tcp",
- Type => SOCK_STREAM)
- ) {
- my $st=120+int(rand(240));
- &logthis(
-"<font color=blue>WARNING: Couldn't connect $conserver ($st secs): $@</font>");
- sleep($st);
- exit;
- };
-# --------------------------------------- Send a ping to make other end do USR1
-print $remotesock "init\n";
-$answer=<$remotesock>;
-print $remotesock "$answer";
-$answer=<$remotesock>;
-chomp($answer);
-&logthis("Init reply for $conserver: >$answer<");
-sleep 5;
-print $remotesock "pong\n";
-$answer=<$remotesock>;
-chomp($answer);
-&logthis("Pong reply for $conserver: >$answer<");
-# ----------------------------------------------------------- Initialize cipher
-print $remotesock "ekey\n";
-my $buildkey=<$remotesock>;
-my $key=$conserver.$perlvar{'lonHostID'};
-$key=~tr/a-z/A-Z/;
-$key=~tr/G-P/0-9/;
-$key=~tr/Q-Z/0-9/;
-$key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
-$key=substr($key,0,32);
-my $cipherkey=pack("H32",$key);
-if ($cipher=new IDEA $cipherkey) {
- &logthis("Secure connection initialized: $conserver");
-} else {
- my $st=120+int(rand(240));
- &logthis(
- "<font color=blue>WARNING: ".
- "Could not establish secure connection, $conserver ($st secs)!</font>");
- sleep($st);
- exit;
-}
+# -------------------------------------------------------------- Open other end
+&openremote($conserver);
+ &logthis("<font color=green> Connection to $conserver open </font>");
# ----------------------------------------- We're online, send delayed messages
+ &status("Checking for delayed messages");
my @allbuffered;
my $path="$perlvar{'lonSockDir'}/delayed";
@@ -322,9 +255,10 @@ if ($cipher=new IDEA $cipherkey) {
@allbuffered=grep /\.$conserver$/, readdir DIRHANDLE;
closedir(DIRHANDLE);
my $dfname;
- map {
+ foreach (@allbuffered) {
+ &status("Sending delayed: $_");
$dfname="$path/$_";
- &logthis($dfname);
+ if($DEBUG) { &logthis('Sending '.$dfname); }
my $wcmd;
{
my $dfh=IO::File->new($dfname);
@@ -345,18 +279,19 @@ if ($cipher=new IDEA $cipherkey) {
}
$cmd="enc:$cmdlength:$encrequest\n";
}
-
- print $remotesock "$cmd\n";
- $answer=<$remotesock>;
+ $answer = londtransaction($remotesock, $cmd, 60);
chomp($answer);
- if ($answer ne '') {
+
+ if (($answer ne '') && ($@!~/timeout/)) {
unlink("$dfname");
- &logthis("Delayed $cmd to $conserver: >$answer<");
+ &logthis("Delayed $cmd: >$answer<");
&logperm("S:$conserver:$bcmd");
}
- } @allbuffered;
+ }
+ if($DEBUG) { &logthis("<font color=green> Delayed transactions sent"); }
# ------------------------------------------------------- Listen to UNIX socket
+&status("Opening socket");
unless (
$server = IO::Socket::UNIX->new(Local => $port,
Type => SOCK_STREAM,
@@ -365,11 +300,11 @@ unless (
my $st=120+int(rand(240));
&logthis(
"<font color=blue>WARNING: ".
- "Can't make server socket $conserver ($st secs): $@</font>");
+ "Can't make server socket ($st secs): .. exiting</font>");
sleep($st);
exit;
};
-
+
# -----------------------------------------------------------------------------
&logthis("<font color=green>$conserver online</font>");
@@ -394,11 +329,11 @@ while (1) {
# check for new information on the connections we have
# anything to read or accept?
- foreach $client ($select->can_read(1)) {
+ foreach $client ($select->can_read(00.10)) {
if ($client == $server) {
# accept a new connection
-
+ &status("Accept new connection: $conserver");
$client = $server->accept();
$select->add($client);
nonblock($client);
@@ -413,6 +348,7 @@ while (1) {
delete $outbuffer{$client};
delete $ready{$client};
+ &status("Idle");
$select->remove($client);
close $client;
next;
@@ -420,6 +356,7 @@ while (1) {
$inbuffer{$client} .= $data;
+
# test whether the data in the buffer or the data we
# just read means there is a complete request waiting
# to be fulfilled. If there is, set $ready{$client}
@@ -429,18 +366,20 @@ while (1) {
}
}
}
-
+
# Any complete requests to process?
foreach $client (keys %ready) {
handle($client);
}
-
+
# Buffers to flush?
foreach $client ($select->can_write(1)) {
# Skip this client if we have nothing to say
next unless exists $outbuffer{$client};
$rv = $client->send($outbuffer{$client}, 0);
+
+ unless ($outbuffer{$client} eq "con_lost\n") {
unless (defined $rv) {
# Whine, but move on.
&logthis("I was told I could write, but I can't.\n");
@@ -466,7 +405,17 @@ while (1) {
close($client);
next;
}
+ } else {
+# -------------------------------------------------------- Wow, connection lost
+ &logthis(
+ "<font color=red>CRITICAL: Closing connection</font>");
+ &status("Connection lost");
+ $remotesock->shutdown(2);
+ &logthis("Attempting to open new connection");
+ &openremote($conserver);
+ }
}
+
}
}
@@ -478,11 +427,23 @@ sub handle {
# send output to $outbuffer{$client}
my $client = shift;
my $request;
-
foreach $request (@{$ready{$client}}) {
# ============================================================= Process request
# $request is the text of the request
# put text of reply into $outbuffer{$client}
+# ------------------------------------------------------------ Is this the end?
+ chomp($request);
+ if($DEBUG) {
+ &logthis("<font color=green> Request $request processing starts</font>");
+ }
+ if ($request eq "close_connection_exit\n") {
+ &status("Request close connection");
+ &logthis(
+ "<font color=red>CRITICAL: Request Close Connection ... exiting</font>");
+ $remotesock->shutdown(2);
+ $server->close();
+ exit;
+ }
# -----------------------------------------------------------------------------
if ($request =~ /^encrypt\:/) {
my $cmd=$request;
@@ -495,10 +456,21 @@ sub handle {
$encrequest.=
unpack("H16",$cipher->encrypt(substr($cmd,$encidx,8)));
}
- $request="enc:$cmdlength:$encrequest\n";
+ $request="enc:$cmdlength:$encrequest";
}
- print $remotesock "$request";
- $answer=<$remotesock>;
+# --------------------------------------------------------------- Main exchange
+ $answer = londtransaction($remotesock, $request, 300);
+
+ if($DEBUG) {
+ &logthis("<font color=green> Request data exchange complete");
+ }
+ if ($@=~/timeout/) {
+ $answer='';
+ &logthis(
+ "<font color=red>CRITICAL: Timeout: $request</font>");
+ }
+
+
if ($answer) {
if ($answer =~ /^enc/) {
my ($cmd,$cmdlength,$encinput)=split(/:/,$answer);
@@ -512,15 +484,25 @@ sub handle {
$answer=substr($answer,0,$cmdlength);
$answer.="\n";
}
+ if($DEBUG) {
+ &logthis("sending $answer to client\n");
+ }
$outbuffer{$client} .= $answer;
} else {
$outbuffer{$client} .= "con_lost\n";
}
+ &status("Completed: $request");
+ if($DEBUG) {
+ &logthis("<font color=green> Request processing complete</font>");
+ }
# ===================================================== Done processing request
}
delete $ready{$client};
# -------------------------------------------------------------- End non-forker
+ if($DEBUG) {
+ &logthis("<font color=green> requests for child handled</font>");
+ }
}
# ---------------------------------------------------------- End make_new_child
}
@@ -537,3 +519,458 @@ sub nonblock {
or die "Can't make socket nonblocking: $!\n";
}
+
+sub openremote {
+# ---------------------------------------------------- Client to network server
+
+ my $conserver=shift;
+
+&status("Opening TCP");
+ my $st=120+int(rand(240)); # Sleep before opening:
+
+unless (
+ $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
+ PeerPort => $perlvar{'londPort'},
+ Proto => "tcp",
+ Type => SOCK_STREAM)
+ ) {
+
+ &logthis(
+"<font color=blue>WARNING: Couldn't connect to $conserver ($st secs): </font>");
+ sleep($st);
+ exit;
+ };
+# ----------------------------------------------------------------- Init dialog
+
+&logthis("<font color=green>INFO Connected to $conserver, initing </font>");
+&status("Init dialogue: $conserver");
+
+ $answer = londtransaction($remotesock, "init", 60);
+ chomp($answer);
+ $answer = londtransaction($remotesock, $answer, 60);
+ chomp($answer);
+
+ if ($@=~/timeout/) {
+ &logthis("Timed out during init.. exiting");
+ exit;
+ }
+
+if ($answer ne 'ok') {
+ &logthis("Init reply: >$answer<");
+ my $st=120+int(rand(240));
+ &logthis(
+"<font color=blue>WARNING: Init failed ($st secs)</font>");
+ sleep($st);
+ exit;
+}
+
+sleep 5;
+&status("Ponging");
+print $remotesock "pong\n";
+$answer=<$remotesock>;
+chomp($answer);
+if ($answer!~/^$conserver/) {
+ &logthis("Pong reply: >$answer<");
+}
+# ----------------------------------------------------------- Initialize cipher
+
+&status("Initialize cipher");
+print $remotesock "ekey\n";
+my $buildkey=<$remotesock>;
+my $key=$conserver.$perlvar{'lonHostID'};
+$key=~tr/a-z/A-Z/;
+$key=~tr/G-P/0-9/;
+$key=~tr/Q-Z/0-9/;
+$key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
+$key=substr($key,0,32);
+my $cipherkey=pack("H32",$key);
+if ($cipher=new IDEA $cipherkey) {
+ &logthis("Secure connection initialized");
+} else {
+ my $st=120+int(rand(240));
+ &logthis(
+ "<font color=blue>WARNING: ".
+ "Could not establish secure connection ($st secs)!</font>");
+ sleep($st);
+ exit;
+}
+ &logthis("<font color=green> Remote open success </font>");
+}
+
+
+
+# grabs exception and records it to log before exiting
+sub catchexception {
+ my ($signal)=@_;
+ $SIG{QUIT}='DEFAULT';
+ $SIG{__DIE__}='DEFAULT';
+ chomp($signal);
+ &logthis("<font color=red>CRITICAL: "
+ ."ABNORMAL EXIT. Child $$ for server [$wasserver] died through "
+ ."\"$signal\" with parameter </font>");
+ die("Signal abend");
+}
+
+# -------------------------------------- Routines to see if other box available
+
+#sub online {
+# my $host=shift;
+# &status("Pinging ".$host);
+# my $p=Net::Ping->new("tcp",20);
+# my $online=$p->ping("$host");
+# $p->close();
+# undef ($p);
+# return $online;
+#}
+
+sub connected {
+ my ($local,$remote)=@_;
+ &status("Checking connection $local to $remote");
+ $local=~s/\W//g;
+ $remote=~s/\W//g;
+
+ unless ($hostname{$local}) { return 'local_unknown'; }
+ unless ($hostname{$remote}) { return 'remote_unknown'; }
+
+ #unless (&online($hostname{$local})) { return 'local_offline'; }
+
+ my $ua=new LWP::UserAgent;
+
+ my $request=new HTTP::Request('GET',
+ "http://".$hostname{$local}.'/cgi-bin/ping.pl?'.$remote);
+
+ my $response=$ua->request($request);
+
+ unless ($response->is_success) { return 'local_error'; }
+
+ my $reply=$response->content;
+ $reply=(split("\n",$reply))[0];
+ $reply=~s/\W//g;
+ if ($reply ne $remote) { return $reply; }
+ return 'ok';
+}
+
+
+
+sub hangup {
+ foreach (keys %children) {
+ $wasserver=$children{$_};
+ &status("Closing $wasserver");
+ &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
+ &status("Kill PID $_ for $wasserver");
+ kill ('INT',$_);
+ }
+}
+
+sub HUNTSMAN { # signal handler for SIGINT
+ local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
+ &hangup();
+ my $execdir=$perlvar{'lonDaemons'};
+ unlink("$execdir/logs/lonc.pid");
+ &logthis("<font color=red>CRITICAL: Shutting down</font>");
+ exit; # clean up with dignity
+}
+
+sub HUPSMAN { # signal handler for SIGHUP
+ local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
+ &hangup();
+ &logthis("<font color=red>CRITICAL: Restarting</font>");
+ unlink("$execdir/logs/lonc.pid");
+ my $execdir=$perlvar{'lonDaemons'};
+ exec("$execdir/lonc"); # here we go again
+}
+
+sub checkchildren {
+ &initnewstatus();
+ &logstatus();
+ &logthis('Going to check on the children');
+ foreach (sort keys %children) {
+ sleep 1;
+ unless (kill 'USR1' => $_) {
+ &logthis ('<font color=red>CRITICAL: Child '.$_.' is dead</font>');
+ &logstatus($$.' is dead');
+ }
+ }
+}
+
+sub USRMAN {
+ &logthis("USR1: Trying to establish connections again");
+ %childatt=();
+ &checkchildren();
+}
+
+# -------------------------------------------------- Non-critical communication
+sub subreply {
+ my ($cmd,$server)=@_;
+ my $answer='';
+ if ($server ne $perlvar{'lonHostID'}) {
+ my $peerfile="$perlvar{'lonSockDir'}/$server";
+ my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
+ Type => SOCK_STREAM,
+ Timeout => 10)
+ or return "con_lost";
+
+
+ $answer = londtransaction($sclient, $cmd, 10);
+
+ if ((!$answer) || ($@=~/timeout/)) { $answer="con_lost"; }
+ $SIG{ALRM}='DEFAULT';
+ $SIG{__DIE__}=\&catchexception;
+ } else { $answer='self_reply'; }
+ return $answer;
+}
+
+# --------------------------------------------------------------------- Logging
+
+sub logthis {
+ my $message=shift;
+ my $execdir=$perlvar{'lonDaemons'};
+ my $fh=IO::File->new(">>$execdir/logs/lonc.log");
+ my $now=time;
+ my $local=localtime($now);
+ $lastlog=$local.': '.$message;
+ print $fh "$local ($$) [$conserver] [$status]: $message\n";
+}
+
+#-------------------------------------- londtransaction:
+#
+# Performs a transaction with lond with timeout support.
+# result = londtransaction(socket,request,timeout)
+#
+sub londtransaction {
+ my ($socket, $request, $tmo) = @_;
+
+ if($DEBUG) {
+ &logthis("londtransaction request: $request");
+ }
+
+ # Set the signal handlers: ALRM for timeout and disble the others.
+
+ $SIG{ALRM} = sub { die "timeout" };
+ $SIG{__DIE__} = 'DEFAULT';
+
+ # Disable all but alarm so that only that can interupt the
+ # send /receive.
+ #
+ my $sigset = POSIX::SigSet->new(QUIT, USR1, HUP, INT, TERM);
+ my $priorsigs = POSIX::SigSet->new;
+ unless (defined sigprocmask(SIG_BLOCK, $sigset, $priorsigs)) {
+ &logthis("<font color=red> CRITICAL -- londtransaction ".
+ "failed to block signals </font>");
+ die "could not block signals in londtransaction";
+ }
+ $answer = '';
+ #
+ # Send request to lond.
+ #
+ eval {
+ alarm($tmo);
+ print $socket "$request\n";
+ alarm(0);
+ };
+ # If request didn't timeout, try for the response.
+ #
+
+ if ($@!~/timeout/) {
+ eval {
+ alarm($tmo);
+ $answer = <$socket>;
+ if($DEBUG) {
+ &logthis("Received $answer in londtransaction");
+ }
+ alarm(0);
+ };
+ } else {
+ if($DEBUG) {
+ &logthis("Timeout on send in londtransaction");
+ }
+ }
+ if( ($@ =~ /timeout/) && ($DEBUG)) {
+ &logthis("Timeout on receive in londtransaction");
+ }
+ #
+ # Restore the initial sigmask set.
+ #
+ unless (defined sigprocmask(SIG_UNBLOCK, $priorsigs)) {
+ &logthis("<font color=red> CRITICAL -- londtransaction ".
+ "failed to re-enable signal processing. </font>");
+ die "londtransaction failed to re-enable signals";
+ }
+ #
+ # go back to the prior handler set.
+ #
+ $SIG{ALRM} = 'DEFAULT';
+ $SIG{__DIE__} = \&cathcexception;
+
+ # chomp $answer;
+ if ($DEBUG) {
+ &logthis("Returning $answer in londtransaction");
+ }
+ return $answer;
+
+}
+
+sub logperm {
+ my $message=shift;
+ my $execdir=$perlvar{'lonDaemons'};
+ my $now=time;
+ my $local=localtime($now);
+ my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
+ print $fh "$now:$message:$local\n";
+}
+# ------------------------------------------------------------------ Log status
+
+sub logstatus {
+ my $docdir=$perlvar{'lonDocRoot'};
+ my $fh=IO::File->new(">>$docdir/lon-status/loncstatus.txt");
+ print $fh $$."\t".$conserver."\t".$status."\t".$lastlog."\n";
+}
+
+sub initnewstatus {
+ my $docdir=$perlvar{'lonDocRoot'};
+ my $fh=IO::File->new(">$docdir/lon-status/loncstatus.txt");
+ my $now=time;
+ my $local=localtime($now);
+ print $fh "LONC status $local - parent $$\n\n";
+}
+
+# -------------------------------------------------------------- Status setting
+
+sub status {
+ my $what=shift;
+ my $now=time;
+ my $local=localtime($now);
+ $status=$local.': '.$what;
+}
+
+
+
+# ----------------------------------- POD (plain old documentation, CPAN style)
+
+=head1 NAME
+
+lonc - LON TCP-MySQL-Server Daemon for handling database requests.
+
+=head1 SYNOPSIS
+
+Usage: B<lonc>
+
+Should only be run as user=www. This is a command-line script which
+is invoked by B<loncron>. There is no expectation that a typical user
+will manually start B<lonc> from the command-line. (In other words,
+DO NOT START B<lonc> YOURSELF.)
+
+=head1 DESCRIPTION
+
+Provides persistent TCP connections to the other servers in the network
+through multiplexed domain sockets
+
+B<lonc> forks off children processes that correspond to the other servers
+in the network. Management of these processes can be done at the
+parent process level or the child process level.
+
+ After forking off the children, B<lonc> the B<parent>
+executes a main loop which simply waits for processes to exit.
+As a process exits, a new process managing a link to the same
+peer as the exiting process is created.
+
+B<logs/lonc.log> is the location of log messages.
+
+The process management is now explained in terms of linux shell commands,
+subroutines internal to this code, and signal assignments:
+
+=over 4
+
+=item *
+
+PID is stored in B<logs/lonc.pid>
+
+This is the process id number of the parent B<lonc> process.
+
+=item *
+
+SIGTERM and SIGINT
+
+Parent signal assignment:
+ $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
+
+Child signal assignment:
+ $SIG{INT} = 'DEFAULT'; (and SIGTERM is DEFAULT also)
+(The child dies and a SIGALRM is sent to parent, awaking parent from slumber
+ to restart a new child.)
+
+Command-line invocations:
+ B<kill> B<-s> SIGTERM I<PID>
+ B<kill> B<-s> SIGINT I<PID>
+
+Subroutine B<HUNTSMAN>:
+ This is only invoked for the B<lonc> parent I<PID>.
+This kills all the children, and then the parent.
+The B<lonc.pid> file is cleared.
+
+=item *
+
+SIGHUP
+
+Current bug:
+ This signal can only be processed the first time
+on the parent process. Subsequent SIGHUP signals
+have no effect.
+
+Parent signal assignment:
+ $SIG{HUP} = \&HUPSMAN;
+
+Child signal assignment:
+ none (nothing happens)
+
+Command-line invocations:
+ B<kill> B<-s> SIGHUP I<PID>
+
+Subroutine B<HUPSMAN>:
+ This is only invoked for the B<lonc> parent I<PID>,
+This kills all the children, and then the parent.
+The B<lonc.pid> file is cleared.
+
+=item *
+
+SIGUSR1
+
+Parent signal assignment:
+ $SIG{USR1} = \&USRMAN;
+
+Child signal assignment:
+ $SIG{USR1}= \&logstatus;
+
+Command-line invocations:
+ B<kill> B<-s> SIGUSR1 I<PID>
+
+Subroutine B<USRMAN>:
+ When invoked for the B<lonc> parent I<PID>,
+SIGUSR1 is sent to all the children, and the status of
+each connection is logged.
+
+
+=back
+
+=head1 PREREQUISITES
+
+POSIX
+IO::Socket
+IO::Select
+IO::File
+Socket
+Fcntl
+Tie::RefHash
+Crypt::IDEA
+
+=head1 COREQUISITES
+
+=head1 OSNAMES
+
+linux
+
+=head1 SCRIPT CATEGORIES
+
+Server/Process
+
+=cut