File:  [LON-CAPA] / loncom / lond
Revision 1.90: download - view: text, annotated - select for diffs
Tue Aug 13 00:37:18 2002 UTC (21 years, 7 months ago) by stredwic
Branches: MAIN
CVS tags: version_0_5_1, version_0_5, HEAD
First, added unescaping of $key in lond dump command.
Next, I added a new way to download student course data.  There are now
two functions for storing data, DownloadStudentCourseData and
DownloadStudentCourseDataSeparate.  These two functions base their running
on input parameters.  The option parameters are whether or not to check
the date for downloading, whether or not to store all the dumped data or
extract out the data you want, whether or not to display a status window.
The extracting data parameter will be best utilized if someone adds in the
ability to send a list of what parameters are desired and perhaps some simple
commands to affect how that data is processed, like tries, sum would
sum record the sum of all the tries for a student.  This is just an idea.

Currently, I have all the statistics modules using the extract ability.
This slightly increases in download time, but drastically reduces cache
size.  Possible ideas include pushing the extract to the lond side with a
list of parameter/commands, or even downloading everything to a temp cache,
then extract the necessary data into the cache then removing the temp
cache.  There are lots of other possibilities, which can change the download
time, cache size, and other factors.  Now, only loncoursedata handles the
downloading of data to a hash.

lonstudentassessment was changed slightly to remove ' ' as a link if the
student actually hadn't attempted the problem.

lonproblemanalysis was updated for the new str2hash type functions.  There
are a couple of (cludges/fixes) for it.  Depending on whether or not the
str2hash type functions are changed, these may or may not need to be
updated.

lonproblemstatistics was drastically overhauled.  Most of the processing
was removed.  Now, it just does its few statistics functions and outputs
the table.  Currently, I broke the graph, discussion column, and
discriminant factor columns.  These will be fixed on the next commit soon.
There is also no caching done.  This will also be remedied soon.  The
problem that will need attention with caching is to know when to update
the statistics cached data when a student's course data is updated.

Lastly, I plan to add perhaps a toggle legend display button, another graph
button(percentage correct), a button to send the CSV format(not just display),
and add a toggle button for sorting within a sequence and sorting all
the problems.

Also, I changed the look and feel to be the same as the class list page.
Also, the displaying of sequence headers and child sequences are not
working.  This will be fixed, but thought will be put into how best to
make it look and have a similiar fill for all the table combinations.

#!/usr/bin/perl
# The LearningOnline Network
# lond "LON Daemon" Server (port "LOND" 5663)
#
# $Id: lond,v 1.90 2002/08/13 00:37:18 stredwic 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/
#
# 5/26/99,6/4,6/10,6/11,6/14,6/15,6/26,6/28,6/30,
# 7/8,7/9,7/10,7/12,7/17,7/19,9/21,
# 10/7,10/8,10/9,10/11,10/13,10/15,11/4,11/16,
# 12/7,12/15,01/06,01/11,01/12,01/14,2/8,
# 03/07,05/31 Gerd Kortemeyer
# 06/26 Scott Harrison
# 06/29,06/30,07/14,07/15,07/17,07/20,07/25,09/18 Gerd Kortemeyer
# 12/05 Scott Harrison
# 12/05,12/13,12/29 Gerd Kortemeyer
# YEAR=2001
# Jan 01 Scott Harrison
# 02/12 Gerd Kortemeyer
# 03/15 Scott Harrison
# 03/24 Gerd Kortemeyer
# 04/02 Scott Harrison
# 05/11,05/28,08/30 Gerd Kortemeyer
# 9/30,10/22,11/13,11/15,11/16 Scott Harrison
# 11/26,11/27 Gerd Kortemeyer
# 12/20 Scott Harrison
# 12/22 Gerd Kortemeyer
# YEAR=2002
# 01/20/02,02/05 Gerd Kortemeyer
# 02/05 Guy Albertelli
# 02/07 Scott Harrison
# 02/12 Gerd Kortemeyer
# 02/19 Matthew Hall
# 02/25 Gerd Kortemeyer
# 05/11 Scott Harrison
###

# based on "Perl Cookbook" ISBN 1-56592-243-3
# preforker - server who forks first
# runs as a daemon
# HUPs
# uses IDEA encryption

use lib '/home/httpd/lib/perl/';
use LONCAPA::Configuration;

use IO::Socket;
use IO::File;
use Apache::File;
use Symbol;
use POSIX;
use Crypt::IDEA;
use LWP::UserAgent();
use GDBM_File;
use Authen::Krb4;
use lib '/home/httpd/lib/perl/';
use localauth;

my $DEBUG = 0;		       # Non zero to enable debug log entries.

my $status='';
my $lastlog='';

# grabs exception and records it to log before exiting
sub catchexception {
    my ($error)=@_;
    $SIG{'QUIT'}='DEFAULT';
    $SIG{__DIE__}='DEFAULT';
    &logthis("<font color=red>CRITICAL: "
     ."ABNORMAL EXIT. Child $$ for server $wasserver died through "
     ."a crash with this error msg->[$error]</font>");
    &logthis('Famous last words: '.$status.' - '.$lastlog);
    if ($client) { print $client "error: $error\n"; }
    $server->close();
    die($error);
}

sub timeout {
    &logthis("<font color=ref>CRITICAL: TIME OUT ".$$."</font>");
    &catchexception('Timeout');
}
# -------------------------------- Set signal handlers to record abnormal exits

$SIG{'QUIT'}=\&catchexception;
$SIG{__DIE__}=\&catchexception;

# ---------------------------------- Read loncapa_apache.conf and loncapa.conf
&status("Read loncapa_apache.conf and loncapa.conf");
my $perlvarref=LONCAPA::Configuration::read_conf('loncapa_apache.conf',
                                                 'loncapa.conf');
my %perlvar=%{$perlvarref};
undef $perlvarref;

# ----------------------------- 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.  lond must be run as user www.' |\
 mailto $emailto -s '$subj' > /dev/null");
   exit 1;
}

# --------------------------------------------- Check if other instance running

my $pidfile="$perlvar{'lonDaemons'}/logs/lond.pid";

if (-e $pidfile) {
   my $lfh=IO::File->new("$pidfile");
   my $pide=<$lfh>;
   chomp($pide);
   if (kill 0 => $pide) { die "already running"; }
}

$PREFORK=4; # number of children to maintain, at least four spare

# ------------------------------------------------------------- Read hosts file

open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";

while ($configline=<CONFIG>) {
    my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
    chomp($ip); $ip=~s/\D+$//;
    $hostid{$ip}=$id;
    if ($id eq $perlvar{'lonHostID'}) { $thisserver=$name; }
    $PREFORK++;
}
close(CONFIG);

# establish SERVER socket, bind and listen.
$server = IO::Socket::INET->new(LocalPort => $perlvar{'londPort'},
                                Type      => SOCK_STREAM,
                                Proto     => 'tcp',
                                Reuse     => 1,
                                Listen    => 10 )
  or die "making socket: $@\n";

# --------------------------------------------------------- Do global variables

# global variables

$MAX_CLIENTS_PER_CHILD  = 50;        # number of clients each child should 
                                    # process
%children               = ();       # keys are current child process IDs
$children               = 0;        # current number of children

sub REAPER {                        # takes care of dead children
    $SIG{CHLD} = \&REAPER;
    my $pid = wait;
    if (defined($children{$pid})) {
	&logthis("Child $pid died");
	$children --;
	delete $children{$pid};
    } else {
	&logthis("Unknown Child $pid died");
    }
}

sub HUNTSMAN {                      # signal handler for SIGINT
    local($SIG{CHLD}) = 'IGNORE';   # we're going to kill our children
    kill 'INT' => keys %children;
    &logthis("Free socket: ".shutdown($server,2)); # free up socket
    my $execdir=$perlvar{'lonDaemons'};
    unlink("$execdir/logs/lond.pid");
    &logthis("<font color=red>CRITICAL: Shutting down</font>");
    exit;                           # clean up with dignity
}

sub HUPSMAN {                      # signal handler for SIGHUP
    local($SIG{CHLD}) = 'IGNORE';  # we're going to kill our children
    kill 'INT' => keys %children;
    &logthis("Free socket: ".shutdown($server,2)); # free up socket
    &logthis("<font color=red>CRITICAL: Restarting</font>");
    unlink("$execdir/logs/lond.pid");
    my $execdir=$perlvar{'lonDaemons'};
    exec("$execdir/lond");         # here we go again
}

sub checkchildren {
    &initnewstatus();
    &logstatus();
    &logthis('Going to check on the children');
    $docdir=$perlvar{'lonDocRoot'};
    foreach (sort keys %children) {
	sleep 1;
        unless (kill 'USR1' => $_) {
	    &logthis ('Child '.$_.' is dead');
            &logstatus($$.' is dead');
        } 
    }
    sleep 5;
    foreach (sort keys %children) {
        unless (-e "$docdir/lon-status/londchld/$_.txt") {
	    &logthis('Child '.$_.' did not respond');
	    kill 9 => $_;
	    $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
	    $subj="LON: $perlvar{'lonHostID'} killed lond process $_";
	    my $result=`echo 'Killed lond process $_.' | mailto $emailto -s '$subj' > /dev/null`;
	    $execdir=$perlvar{'lonDaemons'};
	    $result=`/bin/cp $execdir/logs/lond.log $execdir/logs/lond.log.$_`
        }
    }
}

# --------------------------------------------------------------------- Logging

sub logthis {
    my $message=shift;
    my $execdir=$perlvar{'lonDaemons'};
    my $fh=IO::File->new(">>$execdir/logs/lond.log");
    my $now=time;
    my $local=localtime($now);
    $lastlog=$local.': '.$message;
    print $fh "$local ($$): $message\n";
}

# ------------------------- Conditional log if $DEBUG true.
sub Debug {
    my $message = shift;
    if($DEBUG) {
	&logthis($message);
    }
}
# ------------------------------------------------------------------ Log status

sub logstatus {
    my $docdir=$perlvar{'lonDocRoot'};
    {
    my $fh=IO::File->new(">>$docdir/lon-status/londstatus.txt");
    print $fh $$."\t".$status."\t".$lastlog."\n";
    $fh->close();
    }
    {
	my $fh=IO::File->new(">$docdir/lon-status/londchld/$$.txt");
        print $fh $status."\n".$lastlog."\n".time;
        $fh->close();
    }
}

sub initnewstatus {
    my $docdir=$perlvar{'lonDocRoot'};
    my $fh=IO::File->new(">$docdir/lon-status/londstatus.txt");
    my $now=time;
    my $local=localtime($now);
    print $fh "LOND status $local - parent $$\n\n";
    opendir(DIR,"$docdir/lon-status/londchld");
    while ($filename=readdir(DIR)) {
        unlink("$docdir/lon-status/londchld/$filename");
    }
    closedir(DIR);
}

# -------------------------------------------------------------- Status setting

sub status {
    my $what=shift;
    my $now=time;
    my $local=localtime($now);
    $status=$local.': '.$what;
}

# -------------------------------------------------------- Escape Special Chars

sub escape {
    my $str=shift;
    $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
    return $str;
}

# ----------------------------------------------------- Un-Escape Special Chars

sub unescape {
    my $str=shift;
    $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
    return $str;
}

# ----------------------------------------------------------- Send USR1 to lonc

sub reconlonc {
    my $peerfile=shift;
    &logthis("Trying to reconnect for $peerfile");
    my $loncfile="$perlvar{'lonDaemons'}/logs/lonc.pid";
    if (my $fh=IO::File->new("$loncfile")) {
	my $loncpid=<$fh>;
        chomp($loncpid);
        if (kill 0 => $loncpid) {
	    &logthis("lonc at pid $loncpid responding, sending USR1");
            kill USR1 => $loncpid;
            sleep 5;
            if (-e "$peerfile") { return; }
            &logthis("$peerfile still not there, give it another try");
            sleep 10;
            if (-e "$peerfile") { return; }
            &logthis(
 "<font color=blue>WARNING: $peerfile still not there, giving up</font>");
        } else {
	    &logthis(
              "<font color=red>CRITICAL: "
             ."lonc at pid $loncpid not responding, giving up</font>");
        }
    } else {
      &logthis('<font color=red>CRITICAL: lonc not running, giving up</font>');
    }
}

# -------------------------------------------------- Non-critical communication

sub subreply {
    my ($cmd,$server)=@_;
    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"; }
    return $answer;
}

sub reply {
  my ($cmd,$server)=@_;
  my $answer;
  if ($server ne $perlvar{'lonHostID'}) { 
    $answer=subreply($cmd,$server);
    if ($answer eq 'con_lost') {
	$answer=subreply("ping",$server);
        if ($answer ne $server) {
	    &logthis("sub reply: answer != server");
           &reconlonc("$perlvar{'lonSockDir'}/$server");
        }
        $answer=subreply($cmd,$server);
    }
  } else {
    $answer='self_reply';
  } 
  return $answer;
}

# -------------------------------------------------------------- Talk to lonsql

sub sqlreply {
    my ($cmd)=@_;
    my $answer=subsqlreply($cmd);
    if ($answer eq 'con_lost') { $answer=subsqlreply($cmd); }
    return $answer;
}

sub subsqlreply {
    my ($cmd)=@_;
    my $unixsock="mysqlsock";
    my $peerfile="$perlvar{'lonSockDir'}/$unixsock";
    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"; }
    return $answer;
}

# -------------------------------------------- Return path to profile directory

sub propath {
    my ($udom,$uname)=@_;
    $udom=~s/\W//g;
    $uname=~s/\W//g;
    my $subdir=$uname.'__';
    $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
    my $proname="$perlvar{'lonUsersDir'}/$udom/$subdir/$uname";
    return $proname;
} 

# --------------------------------------- Is this the home server of an author?

sub ishome {
    my $author=shift;
    $author=~s/\/home\/httpd\/html\/res\/([^\/]*)\/([^\/]*).*/$1\/$2/;
    my ($udom,$uname)=split(/\//,$author);
    my $proname=propath($udom,$uname);
    if (-e $proname) {
	return 'owner';
    } else {
        return 'not_owner';
    }
}

# ======================================================= Continue main program
# ---------------------------------------------------- Fork once 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

$execdir=$perlvar{'lonDaemons'};
open (PIDSAVE,">$execdir/logs/lond.pid");
print PIDSAVE "$$\n";
close(PIDSAVE);
&logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
&status('Starting');

# ------------------------------------------------------- Now we are on our own
    
# Fork off our children.
for (1 .. $PREFORK) {
    make_new_child();
}

# ----------------------------------------------------- Install signal handlers

&status('Forked children');

$SIG{CHLD} = \&REAPER;
$SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
$SIG{HUP}  = \&HUPSMAN;
$SIG{USR1} = \&checkchildren;

# And maintain the population.
while (1) {
    &status('Sleeping');
    sleep;                          # wait for a signal (i.e., child's death)
    &logthis('Woke up');
    &status('Woke up');
    for ($i = $children; $i < $PREFORK; $i++) {
        make_new_child();           # top up the child pool
    }
}

sub make_new_child {
    my $pid;
    my $cipher;
    my $sigset;
    &logthis("Attempting to start child");    
    # block signal for fork
    $sigset = POSIX::SigSet->new(SIGINT);
    sigprocmask(SIG_BLOCK, $sigset)
        or die "Can't block SIGINT for fork: $!\n";
    
    die "fork: $!" unless defined ($pid = fork);
    
    if ($pid) {
        # Parent records the child's birth and returns.
        sigprocmask(SIG_UNBLOCK, $sigset)
            or die "Can't unblock SIGINT for fork: $!\n";
        $children{$pid} = 1;
        $children++;
        &status('Started child '.$pid);
        return;
    } else {
        # Child can *not* return from this subroutine.
        $SIG{INT} = 'DEFAULT';      # make SIGINT kill us as it did before
        $SIG{USR1}= \&logstatus;
        $SIG{ALRM}= \&timeout;
        $lastlog='Forked ';
        $status='Forked';

        # unblock signals
        sigprocmask(SIG_UNBLOCK, $sigset)
            or die "Can't unblock SIGINT for fork: $!\n";

        $tmpsnum=0;
    
        # handle connections until we've reached $MAX_CLIENTS_PER_CHILD
        for ($i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
            &status('Idle, waiting for connection');
            $client = $server->accept()     or last;
            &status('Accepted connection');
# =============================================================================
            # do something with the connection
# -----------------------------------------------------------------------------
            # see if we know client and check for spoof IP by challenge
            my $caller=getpeername($client);
            my ($port,$iaddr)=unpack_sockaddr_in($caller);
            my $clientip=inet_ntoa($iaddr);
            my $clientrec=($hostid{$clientip} ne undef);
            &logthis(
"<font color=yellow>INFO: Connection $i, $clientip ($hostid{$clientip})</font>"
            );
            &status("Connecting $clientip ($hostid{$clientip})"); 
            my $clientok;
            if ($clientrec) {
	      &status("Waiting for init from $clientip ($hostid{$clientip})");
	      my $remotereq=<$client>;
              $remotereq=~s/\W//g;
              if ($remotereq eq 'init') {
		  my $challenge="$$".time;
                  print $client "$challenge\n";
                  &status(
           "Waiting for challenge reply from $clientip ($hostid{$clientip})"); 
                  $remotereq=<$client>;
                  $remotereq=~s/\W//g;
                  if ($challenge eq $remotereq) {
		      $clientok=1;
                      print $client "ok\n";
                  } else {
		      &logthis(
 "<font color=blue>WARNING: $clientip did not reply challenge</font>");
                      &status('No challenge reply '.$clientip);
                  }
              } else {
		  &logthis(
                    "<font color=blue>WARNING: "
                   ."$clientip failed to initialize: >$remotereq< </font>");
                  &status('No init '.$clientip);
              }
	    } else {
              &logthis(
 "<font color=blue>WARNING: Unknown client $clientip</font>");
              &status('Hung up on '.$clientip);
            }
            if ($clientok) {
# ---------------- New known client connecting, could mean machine online again

	      &reconlonc("$perlvar{'lonSockDir'}/$hostid{$clientip}");
              &logthis(
       "<font color=green>Established connection: $hostid{$clientip}</font>");
              &status('Will listen to '.$hostid{$clientip});
# ------------------------------------------------------------ Process requests
              while (my $userinput=<$client>) {
                chomp($userinput);
		Debug("Request = $userinput\n");
                &status('Processing '.$hostid{$clientip}.': '.$userinput);
                my $wasenc=0;
                alarm(120);
# ------------------------------------------------------------ See if encrypted
		if ($userinput =~ /^enc/) {
		  if ($cipher) {
                    my ($cmd,$cmdlength,$encinput)=split(/:/,$userinput);
		    $userinput='';
                    for (my $encidx=0;$encidx<length($encinput);$encidx+=16) {
                       $userinput.=
			   $cipher->decrypt(
                            pack("H16",substr($encinput,$encidx,16))
                           );
		    }
		    $userinput=substr($userinput,0,$cmdlength);
                    $wasenc=1;
		}
	      }
	  
# ------------------------------------------------------------- Normal commands
# ------------------------------------------------------------------------ ping
		   if ($userinput =~ /^ping/) {
                       print $client "$perlvar{'lonHostID'}\n";
# ------------------------------------------------------------------------ pong
		   } elsif ($userinput =~ /^pong/) {
                       $reply=reply("ping",$hostid{$clientip});
                       print $client "$perlvar{'lonHostID'}:$reply\n"; 
# ------------------------------------------------------------------------ ekey
		   } elsif ($userinput =~ /^ekey/) {
                       my $buildkey=time.$$.int(rand 100000);
                       $buildkey=~tr/1-6/A-F/;
                       $buildkey=int(rand 100000).$buildkey.int(rand 100000);
                       my $key=$perlvar{'lonHostID'}.$hostid{$clientip};
                       $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);
                       $cipher=new IDEA $cipherkey;
                       print $client "$buildkey\n"; 
# ------------------------------------------------------------------------ load
		   } elsif ($userinput =~ /^load/) {
                       my $loadavg;
                       {
                          my $loadfile=IO::File->new('/proc/loadavg');
                          $loadavg=<$loadfile>;
                       }
                       $loadavg =~ s/\s.*//g;
                       my $loadpercent=100*$loadavg/$perlvar{'lonLoadLim'};
		       print $client "$loadpercent\n";
# ----------------------------------------------------------------- currentauth
		   } elsif ($userinput =~ /^currentauth/) {
		     if ($wasenc==1) {
                       my ($cmd,$udom,$uname)=split(/:/,$userinput);
		       my $result = GetAuthType($udom, $uname);
		       if($result eq "nouser") {
			   print $client "unknown_user\n";
		       }
		       else {
			   print $client "$result\n"
		       }
		     } else {
		       print $client "refused\n";
		     }
# ------------------------------------------------------------------------ auth
                   } elsif ($userinput =~ /^auth/) {
		     if ($wasenc==1) {
                       my ($cmd,$udom,$uname,$upass)=split(/:/,$userinput);
                       chomp($upass);
                       $upass=unescape($upass);
                       my $proname=propath($udom,$uname);
                       my $passfilename="$proname/passwd";
                       if (-e $passfilename) {
                          my $pf = IO::File->new($passfilename);
                          my $realpasswd=<$pf>;
                          chomp($realpasswd);
                          my ($howpwd,$contentpwd)=split(/:/,$realpasswd);
                          my $pwdcorrect=0;
                          if ($howpwd eq 'internal') {
			      $pwdcorrect=
				  (crypt($upass,$contentpwd) eq $contentpwd);
                          } elsif ($howpwd eq 'unix') {
                              $contentpwd=(getpwnam($uname))[1];
			      my $pwauth_path="/usr/local/sbin/pwauth";
			      unless ($contentpwd eq 'x') {
				  $pwdcorrect=
                                    (crypt($upass,$contentpwd) eq $contentpwd);
			      }
			      elsif (-e $pwauth_path) {
				  open PWAUTH, "|$pwauth_path" or
				      die "Cannot invoke authentication";
				  print PWAUTH "$uname\n$upass\n";
				  close PWAUTH;
				  $pwdcorrect=!$?;
			      }
                          } elsif ($howpwd eq 'krb4') {
                             $null=pack("C",0);
			     unless ($upass=~/$null/) {
                              $pwdcorrect=(
                                 Authen::Krb4::get_pw_in_tkt($uname,"",
                                        $contentpwd,'krbtgt',$contentpwd,1,
							     $upass) == 0);
			     } else { $pwdcorrect=0; }
                          } elsif ($howpwd eq 'localauth') {
			    $pwdcorrect=&localauth::localauth($uname,$upass,
							      $contentpwd);
			  }
                          if ($pwdcorrect) {
                             print $client "authorized\n";
                          } else {
                             print $client "non_authorized\n";
                          }  
		       } else {
                          print $client "unknown_user\n";
                       }
		     } else {
		       print $client "refused\n";
		     }
# ---------------------------------------------------------------------- passwd
                   } elsif ($userinput =~ /^passwd/) {
		     if ($wasenc==1) {
                       my 
                       ($cmd,$udom,$uname,$upass,$npass)=split(/:/,$userinput);
                       chomp($npass);
                       $upass=&unescape($upass);
                       $npass=&unescape($npass);
		       &logthis("Trying to change password for $uname");
		       my $proname=propath($udom,$uname);
                       my $passfilename="$proname/passwd";
                       if (-e $passfilename) {
			   my $realpasswd;
                          { my $pf = IO::File->new($passfilename);
			    $realpasswd=<$pf>; }
                          chomp($realpasswd);
                          my ($howpwd,$contentpwd)=split(/:/,$realpasswd);
                          if ($howpwd eq 'internal') {
			   if (crypt($upass,$contentpwd) eq $contentpwd) {
			     my $salt=time;
                             $salt=substr($salt,6,2);
			     my $ncpass=crypt($npass,$salt);
                             { my $pf = IO::File->new(">$passfilename");
 	  		       print $pf "internal:$ncpass\n"; }             
			     &logthis("Result of password change for $uname: pwchange_success");
                             print $client "ok\n";
                           } else {
                             print $client "non_authorized\n";
                           }
                          } elsif ($howpwd eq 'unix') {
			      # Unix means we have to access /etc/password
			      # one way or another.
			      # First: Make sure the current password is
			      #        correct
			      $contentpwd=(getpwnam($uname))[1];
			      my $pwdcorrect = "0";
			      my $pwauth_path="/usr/local/sbin/pwauth";
			      unless ($contentpwd eq 'x') {
				  $pwdcorrect=
                                    (crypt($upass,$contentpwd) eq $contentpwd);
			      } elsif (-e $pwauth_path) {
				  open PWAUTH, "|$pwauth_path" or
				      die "Cannot invoke authentication";
				  print PWAUTH "$uname\n$upass\n";
				  close PWAUTH;
				  $pwdcorrect=!$?;
			      }
			     if ($pwdcorrect) {
				 my $execdir=$perlvar{'lonDaemons'};
				 my $pf = IO::File->new("|$execdir/lcpasswd");
				 print $pf "$uname\n$npass\n$npass\n";
				 close $pf;
				 my $result = ($?>0 ? 'pwchange_failure' 
					       : 'ok');
				 &logthis("Result of password change for $uname: $result");
				 print $client "$result\n";
			     } else {
				 print $client "non_authorized\n";
			     }
			  } else {
                            print $client "auth_mode_error\n";
                          }  
		       } else {
                          print $client "unknown_user\n";
                       }
		     } else {
		       print $client "refused\n";
		     }
# -------------------------------------------------------------------- makeuser
                   } elsif ($userinput =~ /^makeuser/) {
		     Debug("Make user received");
    	             my $oldumask=umask(0077);
		     if ($wasenc==1) {
                       my 
                       ($cmd,$udom,$uname,$umode,$npass)=split(/:/,$userinput);
		       &Debug("cmd =".$cmd." $udom =".$udom.
				    " uname=".$uname);
                       chomp($npass);
                       $npass=&unescape($npass);
                       my $proname=propath($udom,$uname);
                       my $passfilename="$proname/passwd";
		       &Debug("Password file created will be:".
				    $passfilename);
                       if (-e $passfilename) {
			   print $client "already_exists\n";
                       } elsif ($udom ne $perlvar{'lonDefDomain'}) {
                           print $client "not_right_domain\n";
                       } else {
                           @fpparts=split(/\//,$proname);
                           $fpnow=$fpparts[0].'/'.$fpparts[1].'/'.$fpparts[2];
                           $fperror='';
                           for ($i=3;$i<=$#fpparts;$i++) {
                               $fpnow.='/'.$fpparts[$i]; 
                               unless (-e $fpnow) {
				   unless (mkdir($fpnow,0777)) {
                                      $fperror="error:$!";
                                   }
                               }
                           }
                           unless ($fperror) {
			     if ($umode eq 'krb4') {
                               { 
                                 my $pf = IO::File->new(">$passfilename");
 	  		         print $pf "krb4:$npass\n"; 
                               }             
                               print $client "ok\n";
                             } elsif ($umode eq 'internal') {
			       my $salt=time;
                               $salt=substr($salt,6,2);
			       my $ncpass=crypt($npass,$salt);
                               { 
				 &Debug("Creating internal auth");
				 my $pf = IO::File->new(">$passfilename");
 	  		         print $pf "internal:$ncpass\n"; 
                               }
                               print $client "ok\n";
			     } elsif ($umode eq 'localauth') {
			       {
				 my $pf = IO::File->new(">$passfilename");
  	  		         print $pf "localauth:$npass\n";
			       }
			       print $client "ok\n";
			     } elsif ($umode eq 'unix') {
			       {
				 my $execpath="$perlvar{'lonDaemons'}/".
				              "lcuseradd";
				 {
				     &Debug("Executing external: ".
						  $execpath);
				     my $se = IO::File->new("|$execpath");
				     print $se "$uname\n";
				     print $se "$npass\n";
				     print $se "$npass\n";
				 }
                                 my $pf = IO::File->new(">$passfilename");
 	  		         print $pf "unix:\n"; 
			       }
			       print $client "ok\n";
			     } elsif ($umode eq 'none') {
                               { 
                                 my $pf = IO::File->new(">$passfilename");
 	  		         print $pf "none:\n"; 
                               }             
                               print $client "ok\n";
                             } else {
                               print $client "auth_mode_error\n";
                             }  
                           } else {
                               print $client "$fperror\n";
                           }
                       }
		     } else {
		       print $client "refused\n";
		     }
		     umask($oldumask);
# -------------------------------------------------------------- changeuserauth
                   } elsif ($userinput =~ /^changeuserauth/) {
		       &Debug("Changing authorization");
		      if ($wasenc==1) {
                       my 
                       ($cmd,$udom,$uname,$umode,$npass)=split(/:/,$userinput);
                       chomp($npass);
		       &Debug("cmd = ".$cmd." domain= ".$udom.
			      "uname =".$uname." umode= ".$umode);
                       $npass=&unescape($npass);
                       my $proname=propath($udom,$uname);
                       my $passfilename="$proname/passwd";
		       if ($udom ne $perlvar{'lonDefDomain'}) {
                           print $client "not_right_domain\n";
                       } else {
			   if ($umode eq 'krb4') {
                               { 
				   my $pf = IO::File->new(">$passfilename");
				   print $pf "krb4:$npass\n"; 
                               }             
                               print $client "ok\n";
			   } elsif ($umode eq 'internal') {
			       my $salt=time;
                               $salt=substr($salt,6,2);
			       my $ncpass=crypt($npass,$salt);
                               { 
				   my $pf = IO::File->new(">$passfilename");
				   print $pf "internal:$ncpass\n"; 
                               }
                               print $client "ok\n";
			   } elsif ($umode eq 'localauth') {
			       {
				   my $pf = IO::File->new(">$passfilename");
				   print $pf "localauth:$npass\n";
			       }
			       print $client "ok\n";
			   } elsif ($umode eq 'unix') {
			       {
				   my $execpath="$perlvar{'lonDaemons'}/".
				       "lcuseradd";
				   {
				       my $se = IO::File->new("|$execpath");
				       print $se "$uname\n";
				       print $se "$npass\n";
				       print $se "$npass\n";
				   }
				   my $pf = IO::File->new(">$passfilename");
				   print $pf "unix:\n"; 
			       }
			       print $client "ok\n";
			   } elsif ($umode eq 'none') {
                               { 
				   my $pf = IO::File->new(">$passfilename");
				   print $pf "none:\n"; 
                               }             
                               print $client "ok\n";
			   } else {
                               print $client "auth_mode_error\n";
			   }  
                       }
		     } else {
		       print $client "refused\n";
		     }
# ------------------------------------------------------------------------ home
                   } elsif ($userinput =~ /^home/) {
                       my ($cmd,$udom,$uname)=split(/:/,$userinput);
                       chomp($uname);
                       my $proname=propath($udom,$uname);
                       if (-e $proname) {
                          print $client "found\n";
                       } else {
			  print $client "not_found\n";
                       }
# ---------------------------------------------------------------------- update
                   } elsif ($userinput =~ /^update/) {
                       my ($cmd,$fname)=split(/:/,$userinput);
                       my $ownership=ishome($fname);
                       if ($ownership eq 'not_owner') {
                        if (-e $fname) {
                          my ($dev,$ino,$mode,$nlink,
                              $uid,$gid,$rdev,$size,
                              $atime,$mtime,$ctime,
                              $blksize,$blocks)=stat($fname);
                          $now=time;
                          $since=$now-$atime;
                          if ($since>$perlvar{'lonExpire'}) {
                              $reply=
                                    reply("unsub:$fname","$hostid{$clientip}");
                              unlink("$fname");
                          } else {
			     my $transname="$fname.in.transfer";
                             my $remoteurl=
                                    reply("sub:$fname","$hostid{$clientip}");
                             my $response;
                              {
                             my $ua=new LWP::UserAgent;
                             my $request=new HTTP::Request('GET',"$remoteurl");
                             $response=$ua->request($request,$transname);
			      }
                             if ($response->is_error()) {
				 unlink($transname);
                                 my $message=$response->status_line;
                                 &logthis(
                                  "LWP GET: $message for $fname ($remoteurl)");
                             } else {
	                         if ($remoteurl!~/\.meta$/) {
                                  my $ua=new LWP::UserAgent;
                                  my $mrequest=
                                   new HTTP::Request('GET',$remoteurl.'.meta');
                                  my $mresponse=
                                   $ua->request($mrequest,$fname.'.meta');
                                  if ($mresponse->is_error()) {
		                    unlink($fname.'.meta');
                                  }
	                         }
                                 rename($transname,$fname);
			     }
                          }
                          print $client "ok\n";
                        } else {
                          print $client "not_found\n";
                        }
		       } else {
			print $client "rejected\n";
                       }
# -------------------------------------- fetch a user file from a remote server
                   } elsif ($userinput =~ /^fetchuserfile/) {
                      my ($cmd,$fname)=split(/:/,$userinput);
		      my ($udom,$uname,$ufile)=split(/\//,$fname);
                      my $udir=propath($udom,$uname).'/userfiles';
                      unless (-e $udir) { mkdir($udir,0770); }
                       if (-e $udir) {
                       $ufile=~s/^[\.\~]+//;
                       $ufile=~s/\///g;
                       my $transname=$udir.'/'.$ufile;
                       my $remoteurl='http://'.$clientip.'/userfiles/'.$fname;
                             my $response;
                              {
                             my $ua=new LWP::UserAgent;
                             my $request=new HTTP::Request('GET',"$remoteurl");
                             $response=$ua->request($request,$transname);
			      }
                             if ($response->is_error()) {
				 unlink($transname);
                                 my $message=$response->status_line;
                                 &logthis(
                                  "LWP GET: $message for $fname ($remoteurl)");
				 print $client "failed\n";
                             } else {
                                 print $client "ok\n";
                             }
                     } else {
                       print $client "not_home\n";
                     } 
# ------------------------------------------ authenticate access to a user file
                   } elsif ($userinput =~ /^tokenauthuserfile/) {
                       my ($cmd,$fname,$session)=split(/:/,$userinput);
                       chomp($session);
                       $reply='non_auth';
                       if (open(ENVIN,$perlvar{'lonIDsDir'}.'/'.
                                      $session.'.id')) {
                        while ($line=<ENVIN>) {
			   if ($line=~/userfile\.$fname\=/) { $reply='ok'; }
                        }
                        close(ENVIN);
                        print $client $reply."\n";
		       } else {
			print $client "invalid_token\n";
                       }
# ----------------------------------------------------------------- unsubscribe
                   } elsif ($userinput =~ /^unsub/) {
                       my ($cmd,$fname)=split(/:/,$userinput);
                       if (-e $fname) {
			   print $client &unsub($client,$fname,$clientip);
                       } else {
			   print $client "not_found\n";
                       }
# ------------------------------------------------------------------- subscribe
                   } elsif ($userinput =~ /^sub/) {
		       print $client &subscribe($userinput,$clientip);
# ------------------------------------------------------------------------- log
                   } elsif ($userinput =~ /^log/) {
                       my ($cmd,$udom,$uname,$what)=split(/:/,$userinput);
                       chomp($what);
                       my $proname=propath($udom,$uname);
                       my $now=time;
                       {
			 my $hfh;
			 if ($hfh=IO::File->new(">>$proname/activity.log")) { 
                            print $hfh "$now:$hostid{$clientip}:$what\n";
                            print $client "ok\n"; 
			} else {
                            print $client "error:$!\n";
		        }
		       }
# ------------------------------------------------------------------------- put
                   } elsif ($userinput =~ /^put/) {
                      my ($cmd,$udom,$uname,$namespace,$what)
                          =split(/:/,$userinput);
                      $namespace=~s/\//\_/g;
                      $namespace=~s/\W//g;
                      if ($namespace ne 'roles') {
                       chomp($what);
                       my $proname=propath($udom,$uname);
                       my $now=time;
                       unless ($namespace=~/^nohist\_/) {
			   my $hfh;
			   if (
                             $hfh=IO::File->new(">>$proname/$namespace.hist")
			       ) { print $hfh "P:$now:$what\n"; }
		       }
                       my @pairs=split(/\&/,$what);
      if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_WRCREAT,0640)) {
                           foreach $pair (@pairs) {
			       ($key,$value)=split(/=/,$pair);
                               $hash{$key}=$value;
                           }
			   if (untie(%hash)) {
                              print $client "ok\n";
                           } else {
                              print $client "error:$!\n";
                           }
                       } else {
                           print $client "error:$!\n";
                       }
		      } else {
                          print $client "refused\n";
                      }
# -------------------------------------------------------------------- rolesput
                   } elsif ($userinput =~ /^rolesput/) {
		       &Debug("rolesput");
		    if ($wasenc==1) {
                       my ($cmd,$exedom,$exeuser,$udom,$uname,$what)
                          =split(/:/,$userinput);
		       &Debug("cmd = ".$cmd." exedom= ".$exedom.
				    "user = ".$exeuser." udom=".$udom.
				    "what = ".$what);
                       my $namespace='roles';
                       chomp($what);
                       my $proname=propath($udom,$uname);
                       my $now=time;
                       {
			   my $hfh;
			   if (
                             $hfh=IO::File->new(">>$proname/$namespace.hist")
			       ) { 
                                  print $hfh "P:$now:$exedom:$exeuser:$what\n";
                                 }
		       }
                       my @pairs=split(/\&/,$what);
      if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_WRCREAT,0640)) {
                           foreach $pair (@pairs) {
			       ($key,$value)=split(/=/,$pair);
			       &ManagePermissions($key, $udom, $uname,
						  &GetAuthType( $udom, 
								$uname));
                               $hash{$key}=$value;
			       
                           }
			   if (untie(%hash)) {
                              print $client "ok\n";
                           } else {
                              print $client "error:$!\n";
                           }
                       } else {
                           print $client "error:$!\n";
                       }
		      } else {
                          print $client "refused\n";
                      }
# ------------------------------------------------------------------------- get
                   } elsif ($userinput =~ /^get/) {
                       my ($cmd,$udom,$uname,$namespace,$what)
                          =split(/:/,$userinput);
                       $namespace=~s/\//\_/g;
                       $namespace=~s/\W//g;
                       chomp($what);
                       my @queries=split(/\&/,$what);
                       my $proname=propath($udom,$uname);
                       my $qresult='';
      if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER,0640)) {
                           for ($i=0;$i<=$#queries;$i++) {
                               $qresult.="$hash{$queries[$i]}&";
                           }
			   if (untie(%hash)) {
		              $qresult=~s/\&$//;
                              print $client "$qresult\n";
                           } else {
                              print $client "error:$!\n";
                           }
                       } else {
                           print $client "error:$!\n";
                       }
# ------------------------------------------------------------------------ eget
                   } elsif ($userinput =~ /^eget/) {
                       my ($cmd,$udom,$uname,$namespace,$what)
                          =split(/:/,$userinput);
                       $namespace=~s/\//\_/g;
                       $namespace=~s/\W//g;
                       chomp($what);
                       my @queries=split(/\&/,$what);
                       my $proname=propath($udom,$uname);
                       my $qresult='';
      if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER,0640)) {
                           for ($i=0;$i<=$#queries;$i++) {
                               $qresult.="$hash{$queries[$i]}&";
                           }
			   if (untie(%hash)) {
		              $qresult=~s/\&$//;
                              if ($cipher) {
                                my $cmdlength=length($qresult);
                                $qresult.="         ";
                                my $encqresult='';
                                for 
				(my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
                                 $encqresult.=
                                 unpack("H16",
                                 $cipher->encrypt(substr($qresult,$encidx,8)));
                                }
                                print $client "enc:$cmdlength:$encqresult\n";
			      } else {
			        print $client "error:no_key\n";
                              }
                           } else {
                              print $client "error:$!\n";
                           }
                       } else {
                           print $client "error:$!\n";
                       }
# ------------------------------------------------------------------------- del
                   } elsif ($userinput =~ /^del/) {
                       my ($cmd,$udom,$uname,$namespace,$what)
                          =split(/:/,$userinput);
                       $namespace=~s/\//\_/g;
                       $namespace=~s/\W//g;
                       chomp($what);
                       my $proname=propath($udom,$uname);
                       my $now=time;
                       unless ($namespace=~/^nohist\_/) {
			   my $hfh;
			   if (
                             $hfh=IO::File->new(">>$proname/$namespace.hist")
			       ) { print $hfh "D:$now:$what\n"; }
		       }
                       my @keys=split(/\&/,$what);
      if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_WRCREAT,0640)) {
                           foreach $key (@keys) {
                               delete($hash{$key});
                           }
			   if (untie(%hash)) {
                              print $client "ok\n";
                           } else {
                              print $client "error:$!\n";
                           }
                       } else {
                           print $client "error:$!\n";
                       }
# ------------------------------------------------------------------------ keys
                   } elsif ($userinput =~ /^keys/) {
                       my ($cmd,$udom,$uname,$namespace)
                          =split(/:/,$userinput);
                       $namespace=~s/\//\_/g;
                       $namespace=~s/\W//g;
                       my $proname=propath($udom,$uname);
                       my $qresult='';
      if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER,0640)) {
                           foreach $key (keys %hash) {
                               $qresult.="$key&";
                           }
			   if (untie(%hash)) {
		              $qresult=~s/\&$//;
                              print $client "$qresult\n";
                           } else {
                              print $client "error:$!\n";
                           }
                       } else {
                           print $client "error:$!\n";
                       }
# ------------------------------------------------------------------------ dump
                   } elsif ($userinput =~ /^dump/) {
                       my ($cmd,$udom,$uname,$namespace,$regexp)
                          =split(/:/,$userinput);
                       $namespace=~s/\//\_/g;
                       $namespace=~s/\W//g;
                       if (defined($regexp)) {
                          $regexp=&unescape($regexp);
		       } else {
                          $regexp='.';
		       }
                       my $proname=propath($udom,$uname);
                       my $qresult='';
      if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER,0640)) {
                           study($regexp);
                           foreach $key (keys %hash) {
                               my $unescapeKey = &unescape($key);
                               if (eval('$unescapeKey=~/$regexp/')) {
                                  $qresult.="$key=$hash{$key}&";
                              }
                           }
			   if (untie(%hash)) {
		              $qresult=~s/\&$//;
                              print $client "$qresult\n";
                           } else {
                              print $client "error:$!\n";
                           }
                       } else {
                           print $client "error:$!\n";
                       }
# ----------------------------------------------------------------------- store
                   } elsif ($userinput =~ /^store/) {
                      my ($cmd,$udom,$uname,$namespace,$rid,$what)
                          =split(/:/,$userinput);
                      $namespace=~s/\//\_/g;
                      $namespace=~s/\W//g;
                      if ($namespace ne 'roles') {
                       chomp($what);
                       my $proname=propath($udom,$uname);
                       my $now=time;
                       unless ($namespace=~/^nohist\_/) {
			   my $hfh;
			   if (
                             $hfh=IO::File->new(">>$proname/$namespace.hist")
			       ) { print $hfh "P:$now:$rid:$what\n"; }
		       }
                       my @pairs=split(/\&/,$what);
                         
    if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_WRCREAT,0640)) {
                           my @previouskeys=split(/&/,$hash{"keys:$rid"});
                           my $key;
                           $hash{"version:$rid"}++;
                           my $version=$hash{"version:$rid"};
                           my $allkeys=''; 
                           foreach $pair (@pairs) {
			       ($key,$value)=split(/=/,$pair);
                               $allkeys.=$key.':';
                               $hash{"$version:$rid:$key"}=$value;
                           }
                           $hash{"$version:$rid:timestamp"}=$now;
                           $allkeys.='timestamp';
                           $hash{"$version:keys:$rid"}=$allkeys;
			   if (untie(%hash)) {
                              print $client "ok\n";
                           } else {
                              print $client "error:$!\n";
                           }
                       } else {
                           print $client "error:$!\n";
                       }
		      } else {
                          print $client "refused\n";
                      }
# --------------------------------------------------------------------- restore
                   } elsif ($userinput =~ /^restore/) {
                       my ($cmd,$udom,$uname,$namespace,$rid)
                          =split(/:/,$userinput);
                       $namespace=~s/\//\_/g;
                       $namespace=~s/\W//g;
                       chomp($rid);
                       my $proname=propath($udom,$uname);
                       my $qresult='';
      if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER,0640)) {
                	   my $version=$hash{"version:$rid"};
                           $qresult.="version=$version&";
                           my $scope;
                           for ($scope=1;$scope<=$version;$scope++) {
			      my $vkeys=$hash{"$scope:keys:$rid"};
                              my @keys=split(/:/,$vkeys);
                              my $key;
                              $qresult.="$scope:keys=$vkeys&";
                              foreach $key (@keys) {
	     $qresult.="$scope:$key=".$hash{"$scope:$rid:$key"}."&";
                              }                                  
                           }
			   if (untie(%hash)) {
		              $qresult=~s/\&$//;
                              print $client "$qresult\n";
                           } else {
                              print $client "error:$!\n";
                           }
                       } else {
                           print $client "error:$!\n";
                       }
# -------------------------------------------------------------------- chatsend
                   } elsif ($userinput =~ /^chatsend/) {
                       my ($cmd,$cdom,$cnum,$newpost)=split(/\:/,$userinput);
                       &chatadd($cdom,$cnum,$newpost);
                       print $client "ok\n";
# -------------------------------------------------------------------- chatretr
                   } elsif ($userinput =~ /^chatretr/) {
                       my ($cmd,$cdom,$cnum)=split(/\:/,$userinput);
                       my $reply='';
                       foreach (&getchat($cdom,$cnum)) {
			   $reply.=&escape($_).':';
                       }
                       $reply=~s/\:$//;
                       print $client $reply."\n";
# ------------------------------------------------------------------- querysend
                   } elsif ($userinput =~ /^querysend/) {
                       my ($cmd,$query,
			   $arg1,$arg2,$arg3)=split(/\:/,$userinput);
		       $query=~s/\n*$//g;
		       print $client "".
			       sqlreply("$hostid{$clientip}\&$query".
					"\&$arg1"."\&$arg2"."\&$arg3")."\n";
# ------------------------------------------------------------------ queryreply
                   } elsif ($userinput =~ /^queryreply/) {
                       my ($cmd,$id,$reply)=split(/:/,$userinput); 
		       my $store;
                       my $execdir=$perlvar{'lonDaemons'};
                       if ($store=IO::File->new(">$execdir/tmp/$id")) {
			   $reply=~s/\&/\n/g;
			   print $store $reply;
			   close $store;
			   my $store2=IO::File->new(">$execdir/tmp/$id.end");
			   print $store2 "done\n";
			   close $store2;
			   print $client "ok\n";
		       }
		       else {
			   print $client "error:$!\n";
		       }
# ----------------------------------------------------------------------- idput
                   } elsif ($userinput =~ /^idput/) {
                       my ($cmd,$udom,$what)=split(/:/,$userinput);
                       chomp($what);
                       $udom=~s/\W//g;
                       my $proname="$perlvar{'lonUsersDir'}/$udom/ids";
                       my $now=time;
                       {
			   my $hfh;
			   if (
                             $hfh=IO::File->new(">>$proname.hist")
			       ) { print $hfh "P:$now:$what\n"; }
		       }
                       my @pairs=split(/\&/,$what);
                 if (tie(%hash,'GDBM_File',"$proname.db",&GDBM_WRCREAT,0640)) {
                           foreach $pair (@pairs) {
			       ($key,$value)=split(/=/,$pair);
                               $hash{$key}=$value;
                           }
			   if (untie(%hash)) {
                              print $client "ok\n";
                           } else {
                              print $client "error:$!\n";
                           }
                       } else {
                           print $client "error:$!\n";
                       }
# ----------------------------------------------------------------------- idget
                   } elsif ($userinput =~ /^idget/) {
                       my ($cmd,$udom,$what)=split(/:/,$userinput);
                       chomp($what);
                       $udom=~s/\W//g;
                       my $proname="$perlvar{'lonUsersDir'}/$udom/ids";
                       my @queries=split(/\&/,$what);
                       my $qresult='';
                 if (tie(%hash,'GDBM_File',"$proname.db",&GDBM_READER,0640)) {
                           for ($i=0;$i<=$#queries;$i++) {
                               $qresult.="$hash{$queries[$i]}&";
                           }
			   if (untie(%hash)) {
		              $qresult=~s/\&$//;
                              print $client "$qresult\n";
                           } else {
                              print $client "error:$!\n";
                           }
                       } else {
                           print $client "error:$!\n";
                       }
# ---------------------------------------------------------------------- tmpput
                   } elsif ($userinput =~ /^tmpput/) {
                       my ($cmd,$what)=split(/:/,$userinput);
		       my $store;
                       $tmpsnum++;
                       my $id=$$.'_'.$clientip.'_'.$tmpsnum;
                       $id=~s/\W/\_/g;
                       $what=~s/\n//g;
                       my $execdir=$perlvar{'lonDaemons'};
                       if ($store=IO::File->new(">$execdir/tmp/$id.tmp")) {
			   print $store $what;
			   close $store;
			   print $client "$id\n";
		       }
		       else {
			   print $client "error:$!\n";
		       }

# ---------------------------------------------------------------------- tmpget
                   } elsif ($userinput =~ /^tmpget/) {
                       my ($cmd,$id)=split(/:/,$userinput);
                       chomp($id);
                       $id=~s/\W/\_/g;
                       my $store;
                       my $execdir=$perlvar{'lonDaemons'};
                       if ($store=IO::File->new("$execdir/tmp/$id.tmp")) {
                           my $reply=<$store>;
			   print $client "$reply\n";
                           close $store;
		       }
		       else {
			   print $client "error:$!\n";
		       }

# -------------------------------------------------------------------------- ls
                   } elsif ($userinput =~ /^ls/) {
                       my ($cmd,$ulsdir)=split(/:/,$userinput);
                       my $ulsout='';
                       my $ulsfn;
                       if (-e $ulsdir) {
                           if(-d $ulsdir) {
                               if (opendir(LSDIR,$ulsdir)) {
                                   while ($ulsfn=readdir(LSDIR)) {
                                       my @ulsstats=stat($ulsdir.'/'.$ulsfn);
                                       $ulsout.=$ulsfn.'&'.
                                                join('&',@ulsstats).':';
                                   }
                                   closedir(LSDIR);
                               }
                           } else {
                               my @ulsstats=stat($ulsdir);
                               $ulsout.=$ulsfn.'&'.join('&',@ulsstats).':';
                           }
                       } else {
                          $ulsout='no_such_dir';
                       }
                       if ($ulsout eq '') { $ulsout='empty'; }
                       print $client "$ulsout\n";
# ------------------------------------------------------------------ Hanging up
                   } elsif (($userinput =~ /^exit/) ||
                            ($userinput =~ /^init/)) {
                       &logthis(
      "Client $clientip ($hostid{$clientip}) hanging up: $userinput");
                       print $client "bye\n";
                       $client->close();
		       last;
# ------------------------------------------------------------- unknown command
                   } else {
                       # unknown command
                       print $client "unknown_cmd\n";
                   }
# -------------------------------------------------------------------- complete
		   alarm(0);
                   &status('Listening to '.$hostid{$clientip});
	       }
# --------------------------------------------- client unknown or fishy, refuse
            } else {
	        print $client "refused\n";
                $client->close();
                &logthis("<font color=blue>WARNING: "
                ."Rejected client $clientip, closing connection</font>");
            }
	}              

# =============================================================================
       
	&logthis("<font color=red>CRITICAL: "
		 ."Disconnect from $clientip ($hostid{$clientip})</font>");    
        # tidy up gracefully and finish
    
        $server->close();

        # this exit is VERY important, otherwise the child will become
        # a producer of more and more children, forking yourself into
        # process death.
        exit;
    }
}


#
#   Checks to see if the input roleput request was to set
# an author role.  If so, invokes the lchtmldir script to set
# up a correct public_html 
# Parameters:
#    request   - The request sent to the rolesput subchunk.
#                We're looking for  /domain/_au
#    domain    - The domain in which the user is having roles doctored.
#    user      - Name of the user for which the role is being put.
#    authtype  - The authentication type associated with the user.
#
sub ManagePermissions
{
    my $request = shift;
    my $domain  = shift;
    my $user    = shift;
    my $authtype= shift;

    # See if the request is of the form /$domain/_au

    if($request =~ /^(\/$domain\/_au)$/) { # It's an author rolesput...
	my $execdir = $perlvar{'lonDaemons'};
	my $userhome= "/home/$user" ;
	Debug("system $execdir/lchtmldir $userhome $system $authtype");
	system("$execdir/lchtmldir $userhome $user $authtype");
    }
}
#
#   GetAuthType - Determines the authorization type of a user in a domain.

#     Returns the authorization type or nouser if there is no such user.
#
sub GetAuthType 
{
    my $domain = shift;
    my $user   = shift;

    Debug("GetAuthType( $domain, $user ) \n");
    my $proname    = &propath($domain, $user); 
    my $passwdfile = "$proname/passwd";
    if( -e $passwdfile ) {
	my $pf = IO::File->new($passwdfile);
	my $realpassword = <$pf>;
	chomp($realpassword);
	Debug("Password info = $realpassword\n");
	my ($authtype, $contentpwd) = split(/:/, $realpassword);
	Debug("Authtype = $authtype, content = $contentpwd\n");
	my $availinfo = '';
	if($authtype eq 'krb4') {
	    $availinfo = $contentpwd;
	}

	return "$authtype:$availinfo";
    }
    else {
	Debug("Returning nouser");
	return "nouser";
    }
}

sub addline {
    my ($fname,$hostid,$ip,$newline)=@_;
    my $contents;
    my $found=0;
    my $expr='^'.$hostid.':'.$ip.':';
    $expr =~ s/\./\\\./g;
    if ($sh=IO::File->new("$fname.subscription")) {
	while (my $subline=<$sh>) {
	    if ($subline !~ /$expr/) {$contents.= $subline;} else {$found=1;}
	}
	$sh->close();
    }
    $sh=IO::File->new(">$fname.subscription");
    if ($contents) { print $sh $contents; }
    if ($newline) { print $sh $newline; }
    $sh->close();
    return $found;
}

sub getchat {
    my ($cdom,$cname)=@_;
    my %hash;
    my $proname=&propath($cdom,$cname);
    my @entries=();
    if (tie(%hash,'GDBM_File',"$proname/nohist_chatroom.db",
	    &GDBM_READER(),0640)) {
	@entries=map { $_.':'.$hash{$_} } sort keys %hash;
	untie %hash;
    }
    return @entries;
}

sub chatadd {
    my ($cdom,$cname,$newchat)=@_;
    my %hash;
    my $proname=&propath($cdom,$cname);
    my @entries=();
    if (tie(%hash,'GDBM_File',"$proname/nohist_chatroom.db",
	    &GDBM_WRCREAT(),0640)) {
	@entries=map { $_.':'.$hash{$_} } sort keys %hash;
	my $time=time;
	my ($lastid)=($entries[$#entries]=~/^(\w+)\:/);
	my ($thentime,$idnum)=split(/\_/,$lastid);
	my $newid=$time.'_000000';
	if ($thentime==$time) {
	    $idnum=~s/^0+//;
	    $idnum++;
	    $idnum=substr('000000'.$idnum,-6,6);
	    $newid=$time.'_'.$idnum;
	}
	$hash{$newid}=$newchat;
	my $expired=$time-3600;
	foreach (keys %hash) {
	    my ($thistime)=($_=~/(\d+)\_/);
	    if ($thistime<$expired) {
		delete $hash{$_};
	    }
	}
	untie %hash;
    }
}

sub unsub {
    my ($fname,$clientip)=@_;
    my $result;
    if (unlink("$fname.$hostid{$clientip}")) {
	$result="ok\n";
    } else {
	$result="not_subscribed\n";
    }
    if (-e "$fname.subscription") {
	my $found=&addline($fname,$hostid{$clientip},$clientip,'');
	if ($found) { $result="ok\n"; }
    } else {
	if ($result != "ok\n") { $result="not_subscribed\n"; }
    }
    return $result;
}

sub subscribe {
    my ($userinput,$clientip)=@_;
    my $result;
    my ($cmd,$fname)=split(/:/,$userinput);
    my $ownership=&ishome($fname);
    if ($ownership eq 'owner') {
	if (-e $fname) {
	    if (-d $fname) {
		$result="directory\n";
	    } else {
		if (-e "$fname.$hostid{$clientip}") {&unsub($fname,$clientip);}
		$now=time;
		my $found=&addline($fname,$hostid{$clientip},$clientip,
				   "$hostid{$clientip}:$clientip:$now\n");
		if ($found) { $result="$fname\n"; }
		# if they were subscribed to only meta data, delete that
                # subscription, when you subscribe to a file you also get
                # the metadata
		unless ($fname=~/\.meta$/) { &unsub("$fname.meta",$clientip); }
		$fname=~s/\/home\/httpd\/html\/res/raw/;
		$fname="http://$thisserver/".$fname;
		$result="$fname\n";
	    }
	} else {
	    $result="not_found\n";
	}
    } else {
	$result="rejected\n";
    }
    return $result;
}
# ----------------------------------- POD (plain old documentation, CPAN style)

=head1 NAME

lond - "LON Daemon" Server (port "LOND" 5663)

=head1 SYNOPSIS

Usage: B<lond>

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<lond> from the command-line.  (In other words,
DO NOT START B<lond> YOURSELF.)

=head1 DESCRIPTION

There are two characteristics associated with the running of B<lond>,
PROCESS MANAGEMENT (starting, stopping, handling child processes)
and SERVER-SIDE ACTIVITIES (password authentication, user creation,
subscriptions, etc).  These are described in two large
sections below.

B<PROCESS MANAGEMENT>

Preforker - server who forks first. Runs as a daemon. HUPs.
Uses IDEA encryption

B<lond> 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.

B<logs/lond.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/lond.pid>

This is the process id number of the parent B<lond> 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<lond> 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<lond> parent I<PID>,
This kills all the children, and then the parent.
The B<lond.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<lond> parent I<PID>,
SIGUSR1 is sent to all the children, and the status of
each connection is logged.

=item *

SIGCHLD

Parent signal assignment:
 $SIG{CHLD} = \&REAPER;

Child signal assignment:
 none

Command-line invocations:
 B<kill> B<-s> SIGCHLD I<PID>

Subroutine B<REAPER>:
 This is only invoked for the B<lond> parent I<PID>.
Information pertaining to the child is removed.
The socket port is cleaned up.

=back

B<SERVER-SIDE ACTIVITIES>

Server-side information can be accepted in an encrypted or non-encrypted
method.

=over 4

=item ping

Query a client in the hosts.tab table; "Are you there?"

=item pong

Respond to a ping query.

=item ekey

Read in encrypted key, make cipher.  Respond with a buildkey.

=item load

Respond with CPU load based on a computation upon /proc/loadavg.

=item currentauth

Reply with current authentication information (only over an
encrypted channel).

=item auth

Only over an encrypted channel, reply as to whether a user's
authentication information can be validated.

=item passwd

Allow for a password to be set.

=item makeuser

Make a user.

=item passwd

Allow for authentication mechanism and password to be changed.

=item home

Respond to a question "are you the home for a given user?"

=item update

Update contents of a subscribed resource.

=item unsubscribe

The server is unsubscribing from a resource.

=item subscribe

The server is subscribing to a resource.

=item log

Place in B<logs/lond.log>

=item put

stores hash in namespace

=item rolesput

put a role into a user's environment

=item get

returns hash with keys from array
reference filled in from namespace

=item eget

returns hash with keys from array
reference filled in from namesp (encrypts the return communication)

=item rolesget

get a role from a user's environment

=item del

deletes keys out of array from namespace

=item keys

returns namespace keys

=item dump

dumps the complete (or key matching regexp) namespace into a hash

=item store

stores hash permanently
for this url; hashref needs to be given and should be a \%hashname; the
remaining args aren't required and if they aren't passed or are '' they will
be derived from the ENV

=item restore

returns a hash for a given url

=item querysend

Tells client about the lonsql process that has been launched in response
to a sent query.

=item queryreply

Accept information from lonsql and make appropriate storage in temporary
file space.

=item idput

Defines usernames as corresponding to IDs.  (These "IDs" are unique identifiers
for each student, defined perhaps by the institutional Registrar.)

=item idget

Returns usernames corresponding to IDs.  (These "IDs" are unique identifiers
for each student, defined perhaps by the institutional Registrar.)

=item tmpput

Accept and store information in temporary space.

=item tmpget

Send along temporarily stored information.

=item ls

List part of a user's directory.

=item Hanging up (exit or init)

What to do when a client tells the server that they (the client)
are leaving the network.

=item unknown command

If B<lond> is sent an unknown command (not in the list above),
it replys to the client "unknown_cmd".

=item UNKNOWN CLIENT

If the anti-spoofing algorithm cannot verify the client,
the client is rejected (with a "refused" message sent
to the client, and the connection is closed.

=back

=head1 PREREQUISITES

IO::Socket
IO::File
Apache::File
Symbol
POSIX
Crypt::IDEA
LWP::UserAgent()
GDBM_File
Authen::Krb4

=head1 COREQUISITES

=head1 OSNAMES

linux

=head1 SCRIPT CATEGORIES

Server/Process

=cut

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