--- loncom/Attic/lonc	1999/10/13 17:48:51	1.1.1.1
+++ loncom/Attic/lonc	2002/02/19 21:12:22	1.26
@@ -5,12 +5,47 @@
 # provides persistent TCP connections to the other servers in the network
 # through multiplexed domain sockets
 #
+# $Id: lonc,v 1.26 2002/02/19 21:12:22 www 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
 # USR1 tries to open connections again
 
-# 6/4/99,6/5,6/7,6/8,6/9,6/10,6/11,6/12,7/14,7/19,10/8,10/9 Gerd Kortemeyer 
+# 6/4/99,6/5,6/7,6/8,6/9,6/10,6/11,6/12,7/14,7/19,
+# 10/8,10/9,10/15,11/18,12/22,
+# 2/8,7/25 Gerd Kortemeyer
+# 12/05 Scott Harrison
+# 12/05 Gerd Kortemeyer
+# YEAR=2001
+# 01/10/01 Scott Harrison
+# 03/14/01,03/15,06/12,11/26,11/27,11/28 Gerd Kortemeyer
+# 12/20 Scott Harrison
+# YEAR=2002
+# 2/19/02
+# 
 # based on nonforker from Perl Cookbook
 # - server who multiplexes without forking
 
@@ -22,6 +57,67 @@ use Socket;
 use Fcntl;
 use Tie::RefHash;
 use Crypt::IDEA;
+use Net::Ping;
+use LWP::UserAgent();
+
+my $status='';
+my $lastlog='';
+
+# grabs exception and records it to log before exiting
+sub catchexception {
+    my ($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=5;
+
+# -------------------------------------- Routines to see if other box available
+
+sub online {
+    my $host=shift;
+    my $p=Net::Ping->new("tcp",10);
+    my $online=$p->ping("$host");
+    $p->close();
+    undef ($p);
+    return $online;
+}
+
+sub connected {
+    my ($local,$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 $reply; }
+    return 'ok';
+}
+
+
+# -------------------------------- Set signal handlers to record abnormal exits
+
+$SIG{QUIT}=\&catchexception;
+$SIG{__DIE__}=\&catchexception;
 
 # ------------------------------------ Read httpd access.conf and get variables
 
@@ -30,11 +126,33 @@ open (CONFIG,"/etc/httpd/conf/access.con
 while ($configline=<CONFIG>) {
     if ($configline =~ /PerlSetVar/) {
 	my ($dummy,$varname,$varvalue)=split(/\s+/,$configline);
+        chomp($varvalue);
         $perlvar{$varname}=$varvalue;
     }
 }
 close(CONFIG);
 
+# ----------------------------- Make sure this process is running from user=www
+my $wwwid=getpwnam('www');
+if ($wwwid!=$<) {
+   $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
+   $subj="LON: $perlvar{'lonHostID'} User ID mismatch";
+   system("echo 'User ID mismatch.  lonc must be run as user www.' |\
+ mailto $emailto -s '$subj' > /dev/null");
+   exit 1;
+}
+
+# --------------------------------------------- Check if other instance running
+
+my $pidfile="$perlvar{'lonDaemons'}/logs/lonc.pid";
+
+if (-e $pidfile) {
+   my $lfh=IO::File->new("$pidfile");
+   my $pide=<$lfh>;
+   chomp($pide);
+   if (kill 0 => $pide) { die "already running"; }
+}
+
 # ------------------------------------------------------------- Read hosts file
 
 open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
@@ -59,7 +177,8 @@ sub REAPER {                        # ta
     $SIG{CHLD} = \&REAPER;
     my $pid = wait;
     my $wasserver=$children{$pid};
-    &logthis("Child $pid for server $wasserver died");
+    &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";
@@ -68,44 +187,83 @@ sub REAPER {                        # ta
 
 sub HUNTSMAN {                      # signal handler for SIGINT
     local($SIG{CHLD}) = 'IGNORE';   # we're going to kill our children
-    kill 'INT' => keys %children;
+    foreach (keys %children) {
+        $wasserver=$children{$_};
+        &status("Closing $wasserver");
+        &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
+        &status("Kill PID $_ for $wasserver");
+	kill ('INT',$_);
+    }
     my $execdir=$perlvar{'lonDaemons'};
     unlink("$execdir/logs/lonc.pid");
-    &logthis("Shutting down");
+    &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("Restarting");
+    foreach (keys %children) {
+        $wasserver=$children{$_};
+        &status("Closing $wasserver");
+        &logthis('Closing '.$wasserver.': '.&subreply('exit',$wasserver));
+        &status("Kill PID $_ for $wasserver");
+	kill ('INT',$_);
+    }
+    &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' => $_) {
+	    &logthis ('Child '.$_.' is dead');
+            &logstatus($$.' is dead');
+        } 
+    }
+}
+
 sub USRMAN {
-    %childatt=();
     &logthis("USR1: Trying to establish connections again");
     foreach $thisserver (keys %hostip) {
 	$answer=subreply("ping",$thisserver);
-        &logthis(
-          "USR1: Ping $thisserver (pid >$childpid{$thisserver}<): >$answer<");
+        &logthis("USR1: Ping $thisserver "
+        ."(pid >$childpid{$thisserver}<, $childatt{thisserver} attempts): "
+        ." >$answer<");
     }
+    %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";
-    print $sclient "$cmd\n";
-    my $answer=<$sclient>;
-    chomp($answer);
-    if (!$answer) { $answer="con_lost"; }
+
+
+    $SIG{ALRM}=sub { die "timeout" };
+    $SIG{__DIE__}='DEFAULT';
+    eval {
+     alarm(10);
+     print $sclient "$cmd\n";
+     $answer=<$sclient>;
+     chomp($answer);
+     alarm(0);
+    };
+    if ((!$answer) || ($@=~/timeout/)) { $answer="con_lost"; }
+    $SIG{ALRM}='DEFAULT';
+    $SIG{__DIE__}=\&catchexception;
  } else { $answer='self_reply'; }
  return $answer;
 }
@@ -118,9 +276,45 @@ sub logthis {
     my $fh=IO::File->new(">>$execdir/logs/lonc.log");
     my $now=time;
     my $local=localtime($now);
+    $lastlog=$local.': '.$message;
     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";
+}
+# ------------------------------------------------------------------ Log status
+
+sub logstatus {
+    my $docdir=$perlvar{'lonDocRoot'};
+    my $fh=IO::File->new(">>$docdir/lon-status/loncstatus.txt");
+    print $fh $$."\t".$status."\t".$lastlog."\n";
+}
+
+sub initnewstatus {
+    my $docdir=$perlvar{'lonDocRoot'};
+    my $fh=IO::File->new(">$docdir/lon-status/loncstatus.txt");
+    my $now=time;
+    my $local=localtime($now);
+    print $fh "LONC status $local - parent $$\n\n";
+}
+
+# -------------------------------------------------------------- Status setting
+
+sub status {
+    my $what=shift;
+    my $now=time;
+    my $local=localtime($now);
+    $status=$local.': '.$what;
+}
+
+
 # ---------------------------------------------------- Fork once and dissociate
 
 $fpid=fork;
@@ -135,7 +329,7 @@ $execdir=$perlvar{'lonDaemons'};
 open (PIDSAVE,">$execdir/logs/lonc.pid");
 print PIDSAVE "$$\n";
 close(PIDSAVE);
-&logthis("---------- Starting ----------");
+&logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
 
 # ----------------------------- Ignore signals generated during initial startup
 $SIG{HUP}=$SIG{USR1}='IGNORE';
@@ -143,8 +337,12 @@ $SIG{HUP}=$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");
@@ -157,14 +355,25 @@ $SIG{USR1} = \&USRMAN;
 
 # And maintain the population.
 while (1) {
+    &status("Sleeping");
     sleep;                          # wait for a signal (i.e., child's death)
                                     # See who died and start new one
+    &status("Woke up");
     foreach $thisserver (keys %hostip) {
         if (!$childpid{$thisserver}) {
-	    if ($childatt{$thisserver}<5) {
+	    if (($childatt{$thisserver}<$childmaxattempts) &&
+                (&online($hostname{$thisserver}))) {
+	       $childatt{$thisserver}++;
+               &logthis(
+   "<font color=yellow>INFO: Trying to reconnect for $thisserver "
+  ."($childatt{$thisserver} of $childmaxattempts attempts)</font>"); 
                make_new_child($thisserver);
-               $childatt{$thisserver}++;
-	    }
+	   } else {
+               &logthis(
+   "<font color=yellow>INFO: Skipping $thisserver "
+  ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");
+           } 
+               
         }       
     }
 }
@@ -193,7 +402,8 @@ sub make_new_child {
     } else {
         # 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";
@@ -203,28 +413,64 @@ sub make_new_child {
 $port = "$perlvar{'lonSockDir'}/$conserver";
 
 unlink($port);
+
 # ---------------------------------------------------- Client to network server
+
+&status("Opening TCP: $conserver");
+
 unless (
   $remotesock = IO::Socket::INET->new(PeerAddr => $hostip{$conserver},
                                       PeerPort => $perlvar{'londPort'},
                                       Proto    => "tcp",
                                       Type     => SOCK_STREAM)
-   ) { &logthis("Couldn't connect $conserver: $@");
-       sleep(5);
+   ) { 
+       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 "ping\n";
+# ----------------------------------------------------------------- Init dialog
+
+&status("Init dialogue: $conserver");
+
+     $SIG{ALRM}=sub { die "timeout" };
+     $SIG{__DIE__}='DEFAULT';
+     eval {
+         alarm(60);
+print $remotesock "init\n";
+$answer=<$remotesock>;
+print $remotesock "$answer";
 $answer=<$remotesock>;
 chomp($answer);
-&logthis("Ping reply for $conserver: >$answer<");
+          alarm(0);
+     };
+     $SIG{ALRM}='DEFAULT';
+     $SIG{__DIE__}=\&catchexception;
+ 
+     if ($@=~/timeout/) {
+	 &logthis("Timed out during init: $conserver");
+         exit;
+     }
+
+
+&logthis("Init reply for $conserver: >$answer<");
+if ($answer ne 'ok') {
+       my $st=120+int(rand(240));
+       &logthis(
+"<font color=blue>WARNING: Init failed $conserver ($st secs)</font>");
+       sleep($st);
+       exit; 
+}
 sleep 5;
+&status("Ponging $conserver");
 print $remotesock "pong\n";
 $answer=<$remotesock>;
 chomp($answer);
 &logthis("Pong reply for $conserver: >$answer<");
 # ----------------------------------------------------------- Initialize cipher
 
+&status("Initialize cipher: $conserver");
 print $remotesock "ekey\n";
 my $buildkey=<$remotesock>;
 my $key=$conserver.$perlvar{'lonHostID'};
@@ -235,24 +481,87 @@ $key=$key.$buildkey.$key.$buildkey.$key.
 $key=substr($key,0,32);
 my $cipherkey=pack("H32",$key);
 if ($cipher=new IDEA $cipherkey) {
-   &logthis("Secure connection inititalized: $conserver");
+   &logthis("Secure connection initialized: $conserver");
 } else {
-   &logthis("Error: Could not establish secure connection, $conserver!");
-}
-
+   my $st=120+int(rand(240));
+   &logthis(
+     "<font color=blue>WARNING: ".
+     "Could not establish secure connection, $conserver ($st secs)!</font>");
+   sleep($st);
+   exit;
+}
+
+# ----------------------------------------- We're online, send delayed messages
+    &status("Checking for delayed messages");
+    my @allbuffered;
+    my $path="$perlvar{'lonSockDir'}/delayed";
+    opendir(DIRHANDLE,$path);
+    @allbuffered=grep /\.$conserver$/, readdir DIRHANDLE;
+    closedir(DIRHANDLE);
+    my $dfname;
+    foreach (@allbuffered) {
+        &status("Sending delayed $conserver $_");
+        $dfname="$path/$_";
+        &logthis($dfname);
+        my $wcmd;
+        {
+         my $dfh=IO::File->new($dfname);
+         $cmd=<$dfh>;
+        }
+        chomp($cmd);
+        my $bcmd=$cmd;
+        if ($cmd =~ /^encrypt\:/) {
+	    my $rcmd=$cmd;
+            $rcmd =~ s/^encrypt\://;
+            chomp($rcmd);
+            my $cmdlength=length($rcmd);
+            $rcmd.="         ";
+            my $encrequest='';
+            for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
+                $encrequest.=
+                    unpack("H16",$cipher->encrypt(substr($rcmd,$encidx,8)));
+            }
+            $cmd="enc:$cmdlength:$encrequest\n";
+        }
+    $SIG{ALRM}=sub { die "timeout" };
+    $SIG{__DIE__}='DEFAULT';
+    eval {
+        alarm(60);
+        print $remotesock "$cmd\n";
+        $answer=<$remotesock>;
+	chomp($answer);
+        alarm(0);
+    };
+    $SIG{ALRM}='DEFAULT';
+    $SIG{__DIE__}=\&catchexception;
+
+        if (($answer ne '') && ($@!~/timeout/)) {
+	    unlink("$dfname");
+            &logthis("Delayed $cmd to $conserver: >$answer<");
+            &logperm("S:$conserver:$bcmd");
+        }        
+    }
 
 # ------------------------------------------------------- Listen to UNIX socket
+&status("Opening socket $conserver");
 unless (
   $server = IO::Socket::UNIX->new(Local  => $port,
                                   Type   => SOCK_STREAM,
                                   Listen => 10 )
-   ) { &logthis("Can't make server socket $conserver: $@");
-       sleep(5);
+   ) { 
+       my $st=120+int(rand(240));
+       &logthis(
+         "<font color=blue>WARNING: ".
+         "Can't make server socket $conserver ($st secs): $@</font>");
+       sleep($st);
        exit; 
      };
 
 # -----------------------------------------------------------------------------
 
+&logthis("<font color=green>$conserver online</font>");
+
+# -----------------------------------------------------------------------------
 # begin with empty buffers
 %inbuffer  = ();
 %outbuffer = ();
@@ -272,11 +581,11 @@ 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(0.1)) {
 
         if ($client == $server) {
             # accept a new connection
-
+            &status("Accept new connection: $conserver");
             $client = $server->accept();
             $select->add($client);
             nonblock($client);
@@ -291,6 +600,7 @@ while (1) {
                 delete $outbuffer{$client};
                 delete $ready{$client};
 
+                &status("Idle $conserver");
                 $select->remove($client);
                 close $client;
                 next;
@@ -321,16 +631,21 @@ while (1) {
         $rv = $client->send($outbuffer{$client}, 0);
         unless (defined $rv) {
             # Whine, but move on.
-            warn "I was told I could write, but I can't.\n";
+            &logthis("I was told I could write, but I can't.\n");
             next;
         }
+        $errno=$!;
         if (($rv == length $outbuffer{$client}) ||
-            ($! == POSIX::EWOULDBLOCK)) {
+            ($errno == POSIX::EWOULDBLOCK) || ($errno == 0)) {
             substr($outbuffer{$client}, 0, $rv) = '';
             delete $outbuffer{$client} unless length $outbuffer{$client};
         } else {
             # Couldn't write all the data, and it wasn't because
             # it would have blocked.  Shutdown and move on.
+
+	    &logthis("Dropping data with ".$errno.": ".
+                     length($outbuffer{$client}).", $rv");
+
             delete $inbuffer{$client};
             delete $outbuffer{$client};
             delete $ready{$client};
@@ -370,8 +685,27 @@ sub handle {
             }
             $request="enc:$cmdlength:$encrequest\n";
         }
+# --------------------------------------------------------------- Main exchange
+    $SIG{ALRM}=sub { die "timeout" };
+    $SIG{__DIE__}='DEFAULT';
+    eval {
+        alarm(300);
+        &status("Sending $conserver: $request");
         print $remotesock "$request";
+        &status("Waiting for reply from $conserver: $request");
         $answer=<$remotesock>;
+        &status("Received reply: $request");
+        alarm(0);
+    };
+    if ($@=~/timeout/) { 
+       $answer='';
+       &logthis(
+        "<font color=red>CRITICAL: Timeout $conserver: $request</font>");
+    }  
+    $SIG{ALRM}='DEFAULT';
+    $SIG{__DIE__}=\&catchexception;
+
+
         if ($answer) {
 	   if ($answer =~ /^enc/) {
                my ($cmd,$cmdlength,$encinput)=split(/:/,$answer);
@@ -393,6 +727,7 @@ sub handle {
 # ===================================================== Done processing request
     }
     delete $ready{$client};
+    &status("Completed $conserver: $request");
 # -------------------------------------------------------------- End non-forker
 }
 # ---------------------------------------------------------- End make_new_child
@@ -410,7 +745,50 @@ sub nonblock {
             or die "Can't make socket nonblocking: $!\n";
 }
 
+# ----------------------------------- POD (plain old documentation, CPAN style)
+
+=head1 NAME
+
+lonc - LON TCP-MySQL-Server Daemon for handling database requests.
+
+=head1 SYNOPSIS
+
+Should only be run as user=www.  This is a command-line script which
+is invoked by loncron.
+
+=head1 DESCRIPTION
+
+Provides persistent TCP connections to the other servers in the network
+through multiplexed domain sockets
+
+ PID in subdir logs/lonc.pid
+ kill kills
+ HUP restarts
+ USR1 tries to open connections again
+
+=head1 README
+
+Not yet written.
+
+=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