File:  [LON-CAPA] / loncom / lond
Revision 1.165: download - view: text, annotated - select for diffs
Fri Dec 12 21:37:42 2003 UTC (20 years, 3 months ago) by albertel
Branches: MAIN
CVS tags: version_1_1_X, version_1_1_0, version_1_0_99_3, version_1_0_99_2, HEAD
- adding a smattering of status messages to see if I can figure out why lond wedges itself sometimes. (will be  going in 1.1)

#!/usr/bin/perl
# The LearningOnline Network
# lond "LON Daemon" Server (port "LOND" 5663)
#
# $Id: lond,v 1.165 2003/12/12 21:37:42 albertel 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/
#

use strict;
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 Authen::Krb5;
use lib '/home/httpd/lib/perl/';
use localauth;
use File::Copy;

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

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

my $VERSION='$Revision: 1.165 $'; #' stupid emacs
my $remoteVERSION;
my $currenthostid;
my $currentdomainid;

my $client;
my $clientip;
my $clientname;

my $server;
my $thisserver;

# 
#   Connection type is:
#      client                   - All client actions are allowed
#      manager                  - only management functions allowed.
#      both                     - Both management and client actions are allowed
#

my $ConnectionType;

my %hostid;
my %hostdom;
my %hostip;

my %managers;			# Ip -> manager names

my %perlvar;			# Will have the apache conf defined perl vars.

#
#  The array below are password error strings."
#
my $lastpwderror    = 13;		# Largest error number from lcpasswd.
my @passwderrors = ("ok",
		   "lcpasswd must be run as user 'www'",
		   "lcpasswd got incorrect number of arguments",
		   "lcpasswd did not get the right nubmer of input text lines",
		   "lcpasswd too many simultaneous pwd changes in progress",
		   "lcpasswd User does not exist.",
		   "lcpasswd Incorrect current passwd",
		   "lcpasswd Unable to su to root.",
		   "lcpasswd Cannot set new passwd.",
		   "lcpasswd Username has invalid characters",
		   "lcpasswd Invalid characters in password",
		    "11", "12",
		    "lcpasswd Password mismatch");


#  The array below are lcuseradd error strings.:

my $lastadderror = 13;
my @adderrors    = ("ok",
		    "User ID mismatch, lcuseradd must run as user www",
		    "lcuseradd Incorrect number of command line parameters must be 3",
		    "lcuseradd Incorrect number of stdinput lines, must be 3",
		    "lcuseradd Too many other simultaneous pwd changes in progress",
		    "lcuseradd User does not exist",
		    "lcuseradd Unable to make www member of users's group",
		    "lcuseradd Unable to su to root",
		    "lcuseradd Unable to set password",
		    "lcuseradd Usrname has invalid characters",
		    "lcuseradd Password has an invalid character",
		    "lcuseradd User already exists",
		    "lcuseradd Could not add user.",
		    "lcuseradd Password mismatch");


#
#   GetCertificate: Given a transaction that requires a certificate,
#   this function will extract the certificate from the transaction
#   request.  Note that at this point, the only concept of a certificate
#   is the hostname to which we are connected.
#
#   Parameter:
#      request   - The request sent by our client (this parameterization may
#                  need to change when we really use a certificate granting
#                  authority.
#
sub GetCertificate {
    my $request = shift;

    return $clientip;
}

#
#   Return true if client is a manager.
#
sub isManager {
    return (($ConnectionType eq "manager") || ($ConnectionType eq "both"));
}
#
#   Return tru if client can do client functions
#
sub isClient {
    return (($ConnectionType eq "client") || ($ConnectionType eq "both"));
}


#
#   ReadManagerTable: Reads in the current manager table. For now this is
#                     done on each manager authentication because:
#                     - These authentications are not frequent
#                     - This allows dynamic changes to the manager table
#                       without the need to signal to the lond.
#

sub ReadManagerTable {

    #   Clean out the old table first..

    foreach my $key (keys %managers) {
	delete $managers{$key};
    }

    my $tablename = $perlvar{'lonTabDir'}."/managers.tab";
    if (!open (MANAGERS, $tablename)) {
	logthis('<font color="red">No manager table.  Nobody can manage!!</font>');
	return;
    }
    while(my $host = <MANAGERS>) {
	chomp($host);
	if (!defined $hostip{$host}) { # This is a non cluster member

	    #  The entry is of the form:
	    #    cluname:hostname
	    #  cluname - A 'cluster hostname' is needed in order to negotiate
	    #            the host key.
	    #  hostname- The dns name of the host.
	    #
	    
	    my($cluname, $dnsname) = split(/:/, $host);
	    open(MGRPIPE, "/usr/bin/host $dnsname |") || die "Can't make host pipeline";
	    my $dnsinfo = <MGRPIPE>;
	    chomp $dnsinfo;
	    close MGRPIPE;
	    my($jname, $jhas, $jaddress, $hostip) = split(/ /, $dnsinfo);
	    $managers{$hostip} = $cluname;
	} else {
	    $managers{$hostip{$host}} = $host;  # Use info from cluster tab if clumemeber
	}
    }
}

#
#  ValidManager: Determines if a given certificate represents a valid manager.
#                in this primitive implementation, the 'certificate' is
#                just the connecting loncapa client name.  This is checked
#                against a valid client list in the configuration.
#
#                  
sub ValidManager {
    my $certificate = shift; 

    return isManager;
}
#
#  CopyFile:  Called as part of the process of installing a 
#             new configuration file.  This function copies an existing
#             file to a backup file.
# Parameters:
#     oldfile  - Name of the file to backup.
#     newfile  - Name of the backup file.
# Return:
#     0   - Failure (errno has failure reason).
#     1   - Success.
#
sub CopyFile {
    my $oldfile = shift;
    my $newfile = shift;

    #  The file must exist:

    if(-e $oldfile) {

	 # Read the old file.

	my $oldfh = IO::File->new("< $oldfile");
	if(!$oldfh) {
	    return 0;
	}
	my @contents = <$oldfh>;  # Suck in the entire file.

	# write the backup file:

	my $newfh = IO::File->new("> $newfile");
	if(!(defined $newfh)){
	    return 0;
	}
	my $lines = scalar @contents;
	for (my $i =0; $i < $lines; $i++) {
	    print $newfh ($contents[$i]);
	}

	$oldfh->close;
	$newfh->close;

	chmod(0660, $newfile);

	return 1;
	    
    } else {
	return 0;
    }
}
#
#  Host files are passed out with externally visible host IPs.
#  If, for example, we are behind a fire-wall or NAT host, our 
#  internally visible IP may be different than the externally
#  visible IP.  Therefore, we always adjust the contents of the
#  host file so that the entry for ME is the IP that we believe
#  we have.  At present, this is defined as the entry that
#  DNS has for us.  If by some chance we are not able to get a
#  DNS translation for us, then we assume that the host.tab file
#  is correct.  
#    BUGBUGBUG - in the future, we really should see if we can
#       easily query the interface(s) instead.
# Parameter(s):
#     contents    - The contents of the host.tab to check.
# Returns:
#     newcontents - The adjusted contents.
#
#
sub AdjustHostContents {
    my $contents  = shift;
    my $adjusted;
    my $me        = $perlvar{'lonHostID'};

    foreach my $line (split(/\n/,$contents)) {
	if(!(($line eq "") || ($line =~ /^ *\#/) || ($line =~ /^ *$/))) {
	    chomp($line);
	    my ($id,$domain,$role,$name,$ip,$maxcon,$idleto,$mincon)=split(/:/,$line);
	    if ($id eq $me) {
		open(PIPE, " /usr/bin/host $name |") || die "Cant' make host pipeline";
		my $hostinfo = <PIPE>;
		close PIPE;
		
		my ($hostname, $has, $address, $ipnew) = split(/ /,$hostinfo);
		&logthis('<font color="green">'.
			 "hostname = $hostname me = $me, name = $name   actual ip = $ipnew </font>");
		
		if ($hostname eq $name) { # Lookup succeeded..
		    &logthis('<font color="green"> look up ok <font>');
		    $ip = $ipnew;
		} else {
		    &logthis('<font color="green"> Lookup failed: '
			     .$hostname." ne $name </font>");
		}
		#  Reconstruct the host line and append to adjusted:
		
		my $newline = "$id:$domain:$role:$name:$ip";
		if($maxcon ne "") { # Not all hosts have loncnew tuning params
		    $newline .= ":$maxcon:$idleto:$mincon";
		}
		$adjusted .= $newline."\n";
		
	    } else {		# Not me, pass unmodified.
		$adjusted .= $line."\n";
	    }
	} else {                  # Blank or comment never re-written.
	    $adjusted .= $line."\n";	# Pass blanks and comments as is.
	}
    }
    return $adjusted;
}
#
#   InstallFile: Called to install an administrative file:
#       - The file is created with <name>.tmp
#       - The <name>.tmp file is then mv'd to <name>
#   This lugubrious procedure is done to ensure that we are never without
#   a valid, even if dated, version of the file regardless of who crashes
#   and when the crash occurs.
#
#  Parameters:
#       Name of the file
#       File Contents.
#  Return:
#      nonzero - success.
#      0       - failure and $! has an errno.
#
sub InstallFile {
    my $Filename = shift;
    my $Contents = shift;
    my $TempFile = $Filename.".tmp";

    #  Open the file for write:

    my $fh = IO::File->new("> $TempFile"); # Write to temp.
    if(!(defined $fh)) {
	&logthis('<font color="red"> Unable to create '.$TempFile."</font>");
	return 0;
    }
    #  write the contents of the file:

    print $fh ($Contents); 
    $fh->close;			# In case we ever have a filesystem w. locking

    chmod(0660, $TempFile);

    # Now we can move install the file in position.
    
    move($TempFile, $Filename);

    return 1;
}

#
#   PushFile:  Called to do an administrative push of a file.
#              - Ensure the file being pushed is one we support.
#              - Backup the old file to <filename.saved>
#              - Separate the contents of the new file out from the
#                rest of the request.
#              - Write the new file.
#  Parameter:
#     Request - The entire user request.  This consists of a : separated
#               string pushfile:tablename:contents.
#     NOTE:  The contents may have :'s in it as well making things a bit
#            more interesting... but not much.
#  Returns:
#     String to send to client ("ok" or "refused" if bad file).
#
sub PushFile {
    my $request = shift;    
    my ($command, $filename, $contents) = split(":", $request, 3);
    
    #  At this point in time, pushes for only the following tables are
    #  supported:
    #   hosts.tab  ($filename eq host).
    #   domain.tab ($filename eq domain).
    # Construct the destination filename or reject the request.
    #
    # lonManage is supposed to ensure this, however this session could be
    # part of some elaborate spoof that managed somehow to authenticate.
    #

    my $tablefile = $perlvar{'lonTabDir'}.'/'; # need to precede with dir.
    if ($filename eq "host") {
	$tablefile .= "hosts.tab";
    } elsif ($filename eq "domain") {
	$tablefile .= "domain.tab";
    } else {
	return "refused";
    }
    #
    # >copy< the old table to the backup table
    #        don't rename in case system crashes/reboots etc. in the time
    #        window between a rename and write.
    #
    my $backupfile = $tablefile;
    $backupfile    =~ s/\.tab$/.old/;
    if(!CopyFile($tablefile, $backupfile)) {
	&logthis('<font color="green"> CopyFile from '.$tablefile." to ".$backupfile." failed </font>");
	return "error:$!";
    }
    &logthis('<font color="green"> Pushfile: backed up '
	    .$tablefile." to $backupfile</font>");
    
    #  If the file being pushed is the host file, we adjust the entry for ourself so that the
    #  IP will be our current IP as looked up in dns.  Note this is only 99% good as it's possible
    #  to conceive of conditions where we don't have a DNS entry locally.  This is possible in a 
    #  network sense but it doesn't make much sense in a LonCAPA sense so we ignore (for now)
    #  that possibilty.

    if($filename eq "host") {
	$contents = AdjustHostContents($contents);
    }

    #  Install the new file:

    if(!InstallFile($tablefile, $contents)) {
	&logthis('<font color="red"> Pushfile: unable to install '
	 .$tablefile." $! </font>");
	return "error:$!";
    }
    else {
	&logthis('<font color="green"> Installed new '.$tablefile
		 ."</font>");

    }


    #  Indicate success:
 
    return "ok";

}

#
#  Called to re-init either lonc or lond.
#
#  Parameters:
#    request   - The full request by the client.  This is of the form
#                reinit:<process>  
#                where <process> is allowed to be either of 
#                lonc or lond
#
#  Returns:
#     The string to be sent back to the client either:
#   ok         - Everything worked just fine.
#   error:why  - There was a failure and why describes the reason.
#
#
sub ReinitProcess {
    my $request = shift;


    # separate the request (reinit) from the process identifier and
    # validate it producing the name of the .pid file for the process.
    #
    #
    my ($junk, $process) = split(":", $request);
    my $processpidfile = $perlvar{'lonDaemons'}.'/logs/';
    if($process eq 'lonc') {
	$processpidfile = $processpidfile."lonc.pid";
	if (!open(PIDFILE, "< $processpidfile")) {
	    return "error:Open failed for $processpidfile";
	}
	my $loncpid = <PIDFILE>;
	close(PIDFILE);
	logthis('<font color="red"> Reinitializing lonc pid='.$loncpid
		."</font>");
	kill("USR2", $loncpid);
    } elsif ($process eq 'lond') {
	logthis('<font color="red"> Reinitializing self (lond) </font>');
	&UpdateHosts;			# Lond is us!!
    } else {
	&logthis('<font color="yellow" Invalid reinit request for '.$process
		 ."</font>");
	return "error:Invalid process identifier $process";
    }
    return 'ok';
}

#
#  Convert an error return code from lcpasswd to a string value.
#
sub lcpasswdstrerror {
    my $ErrorCode = shift;
    if(($ErrorCode < 0) || ($ErrorCode > $lastpwderror)) {
	return "lcpasswd Unrecognized error return value ".$ErrorCode;
    } else {
	return $passwderrors[$ErrorCode];
    }
}

#
# Convert an error return code from lcuseradd to a string value:
#
sub lcuseraddstrerror {
    my $ErrorCode = shift;
    if(($ErrorCode < 0) || ($ErrorCode > $lastadderror)) {
	return "lcuseradd - Unrecognized error code: ".$ErrorCode;
    } else {
	return $adderrors[$ErrorCode];
    }
}

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

sub timeout {
    &status("Handling 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.conf and loncapa_apache.conf");
my $perlvarref=LONCAPA::Configuration::read_conf('loncapa.conf');
%perlvar=%{$perlvarref};
undef $perlvarref;

# ----------------------------- Make sure this process is running from user=www
my $wwwid=getpwnam('www');
if ($wwwid!=$<) {
   my $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
   my $subj="LON: $currenthostid 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"; }
}

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



# 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

my %children               = ();       # keys are current child process IDs
my $children               = 0;        # current number of children

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

sub HUNTSMAN {                      # signal handler for SIGINT
    &status("Killing children (INT)");
    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>");
    &status("Done killing children");
    exit;                           # clean up with dignity
}

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

#
#    Kill off hashes that describe the host table prior to re-reading it.
#    Hashes affected are:
#       %hostid, %hostdom %hostip
#
sub KillHostHashes {
    foreach my $key (keys %hostid) {
	delete $hostid{$key};
    }
    foreach my $key (keys %hostdom) {
	delete $hostdom{$key};
    }
    foreach my $key (keys %hostip) {
	delete $hostip{$key};
    }
}
#
#   Read in the host table from file and distribute it into the various hashes:
#
#    - %hostid  -  Indexed by IP, the loncapa hostname.
#    - %hostdom -  Indexed by  loncapa hostname, the domain.
#    - %hostip  -  Indexed by hostid, the Ip address of the host.
sub ReadHostTable {

    open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
    
    while (my $configline=<CONFIG>) {
	my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
	chomp($ip); $ip=~s/\D+$//;
	$hostid{$ip}=$id;
	$hostdom{$id}=$domain;
	$hostip{$id}=$ip;
	if ($id eq $perlvar{'lonHostID'}) { $thisserver=$name; }
    }
    close(CONFIG);
}
#
#  Reload the Apache daemon's state.
#  This is done by invoking /home/httpd/perl/apachereload
#  a setuid perl script that can be root for us to do this job.
#
sub ReloadApache {
    my $execdir = $perlvar{'lonDaemons'};
    my $script  = $execdir."/apachereload";
    system($script);
}

#
#   Called in response to a USR2 signal.
#   - Reread hosts.tab
#   - All children connected to hosts that were removed from hosts.tab
#     are killed via SIGINT
#   - All children connected to previously existing hosts are sent SIGUSR1
#   - Our internal hosts hash is updated to reflect the new contents of
#     hosts.tab causing connections from hosts added to hosts.tab to
#     now be honored.
#
sub UpdateHosts {
    &status("Reload hosts.tab");
    logthis('<font color="blue"> Updating connections </font>');
    #
    #  The %children hash has the set of IP's we currently have children
    #  on.  These need to be matched against records in the hosts.tab
    #  Any ip's no longer in the table get killed off they correspond to
    #  either dropped or changed hosts.  Note that the re-read of the table
    #  will take care of new and changed hosts as connections come into being.


    KillHostHashes;
    ReadHostTable;

    foreach my $child (keys %children) {
	my $childip = $children{$child};
	if(!$hostid{$childip}) {
	    logthis('<font color="blue"> UpdateHosts killing child '
		    ." $child for ip $childip </font>");
	    kill('INT', $child);
	} else {
	    logthis('<font color="green"> keeping child for ip '
		    ." $childip (pid=$child) </font>");
	}
    }
    ReloadApache;
    &status("Finished reloading hosts.tab");
}


sub checkchildren {
    &status("Checking on the children (sending signals)");
    &initnewstatus();
    &logstatus();
    &logthis('Going to check on the children');
    my $docdir=$perlvar{'lonDocRoot'};
    foreach (sort keys %children) {
	sleep 1;
        unless (kill 'USR1' => $_) {
	    &logthis ('Child '.$_.' is dead');
            &logstatus($$.' is dead');
        } 
    }
    sleep 5;
    $SIG{ALRM} = sub { die "timeout" };
    $SIG{__DIE__} = 'DEFAULT';
    &status("Checking on the children (waiting for reports)");
    foreach (sort keys %children) {
        unless (-e "$docdir/lon-status/londchld/$_.txt") {
          eval {
            alarm(300);
	    &logthis('Child '.$_.' did not respond');
	    kill 9 => $_;
	    #$emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
	    #$subj="LON: $currenthostid 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 $execdir/logs/lond.log.$_`;
	    alarm(0);
	  }
        }
    }
    $SIG{ALRM} = 'DEFAULT';
    $SIG{__DIE__} = \&catchexception;
    &status("Finished checking children");
}

# --------------------------------------------------------------------- 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);
    }
}

#
#   Sub to do replies to client.. this gives a hook for some
#   debug tracing too:
#  Parameters:
#     fd      - File open on client.
#     reply   - Text to send to client.
#     request - Original request from client.
#
sub Reply {
    my $fd      = shift;
    my $reply   = shift;
    my $request = shift;

    print $fd $reply;
    Debug("Request was $request  Reply was $reply");

}
# ------------------------------------------------------------------ Log status

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

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 (my $filename=readdir(DIR)) {
        unlink("$docdir/lon-status/londchld/$filename");
    }
    closedir(DIR);
}

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

sub status {
    my $what=shift;
    my $now=time;
    my $local=localtime($now);
    $status=$local.': '.$what;
    $0='lond: '.$what.' '.$local;
}

# -------------------------------------------------------- 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;
        } 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 $currenthostid) { 
    $answer=subreply($cmd,$server);
    if ($answer eq 'con_lost') {
	$answer=subreply("ping",$server);
        if ($answer ne $server) {
	    &logthis("sub reply: answer != server answer is $answer, server is $server");
           &reconlonc("$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

my $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

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



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


$SIG{CHLD} = \&REAPER;
$SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
$SIG{HUP}  = \&HUPSMAN;
$SIG{USR1} = \&checkchildren;
$SIG{USR2} = \&UpdateHosts;

#  Read the host hashes:

ReadHostTable;

# --------------------------------------------------------------
#   Accept connections.  When a connection comes in, it is validated
#   and if good, a child process is created to process transactions
#   along the connection.

while (1) {
    &status('Starting accept');
    $client = $server->accept() or next;
    &status('Accepted '.$client.' off to spawn');
    make_new_child($client);
    &status('Finished spawning');
}

sub make_new_child {
    my $pid;
    my $cipher;
    my $sigset;

    $client = shift;
    &status('Starting new child '.$client);
    &logthis('<font color="green"> Attempting to start child ('.$client.
	     ")</font>");    
    # 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);

    $client->sockopt(SO_KEEPALIVE, 1); # Enable monitoring of
	                               # connection liveness.

    #
    #  Figure out who we're talking to so we can record the peer in 
    #  the pid hash.
    #
    my $caller = getpeername($client);
    my ($port,$iaddr)=unpack_sockaddr_in($caller);
    $clientip=inet_ntoa($iaddr);
    
    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} = $clientip;
        $children++;
        &status('Started child '.$pid);
        return;
    } else {
        # Child can *not* return from this subroutine.
        $SIG{INT} = 'DEFAULT';      # make SIGINT kill us as it did before
        $SIG{CHLD} = 'DEFAULT'; #make this default so that pwauth returns 
                                #don't get intercepted
        $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";

        my $tmpsnum=0;
#---------------------------------------------------- kerberos 5 initialization
        &Authen::Krb5::init_context();
        &Authen::Krb5::init_ets();

	&status('Accepted connection');
# =============================================================================
            # do something with the connection
# -----------------------------------------------------------------------------
	# see if we know client and check for spoof IP by challenge

	ReadManagerTable;	# May also be a manager!!
	
	my $clientrec=($hostid{$clientip}     ne undef);
	my $ismanager=($managers{$clientip}    ne undef);
	$clientname  = "[unknonwn]";
	if($clientrec) {	# Establish client type.
	    $ConnectionType = "client";
	    $clientname = $hostid{$clientip};
	    if($ismanager) {
		$ConnectionType = "both";
	    }
	} else {
	    $ConnectionType = "manager";
	    $clientname = $managers{$clientip};
	}
	my $clientok;
	if ($clientrec || $ismanager) {
	    &status("Waiting for init from $clientip $clientname");
	    &logthis('<font color="yellow">INFO: Connection, '.
		     $clientip.
		  " ($clientname) connection type = $ConnectionType </font>" );
	    &status("Connecting $clientip  ($clientname))"); 
	    my $remotereq=<$client>;
	    $remotereq=~s/[^\w:]//g;
	    if ($remotereq =~ /^init/) {
		&sethost("sethost:$perlvar{'lonHostID'}");
		my $challenge="$$".time;
		print $client "$challenge\n";
		&status(
			"Waiting for challenge reply from $clientip ($clientname)"); 
		$remotereq=<$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
	    
	    foreach my $id (keys(%hostip)) {
		if ($hostip{$id} ne $clientip ||
		    $hostip{$currenthostid} eq $clientip) {
		    # no need to try to do recon's to myself
		    next;
		}
		&reconlonc("$perlvar{'lonSockDir'}/$id");
	    }
	    &logthis("<font color=green>Established connection: $clientname</font>");
	    &status('Will listen to '.$clientname);
# ------------------------------------------------------------ Process requests
	    while (my $userinput=<$client>) {
                chomp($userinput);
		Debug("Request = $userinput\n");
                &status('Processing '.$clientname.': '.$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/) {	# client only
		    if(isClient) {
			print $client "$currenthostid\n";
		    } else {
			Reply($client, "refused\n", $userinput);
		    }
# ------------------------------------------------------------------------ pong
		}elsif ($userinput =~ /^pong/) { # client only
		    if(isClient) {
			my $reply=&reply("ping",$clientname);
			print $client "$currenthostid:$reply\n"; 
		    } else {
			Reply($client, "refused\n", $userinput);
		    }
# ------------------------------------------------------------------------ ekey
		} elsif ($userinput =~ /^ekey/) { # ok for both clients & mgrs
		    my $buildkey=time.$$.int(rand 100000);
		    $buildkey=~tr/1-6/A-F/;
		    $buildkey=int(rand 100000).$buildkey.int(rand 100000);
		    my $key=$currenthostid.$clientname;
		    $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/) { # client only
		    if (isClient) {
			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";
		    } else {
			Reply($client, "refused\n", $userinput);
	       
		    }
# -------------------------------------------------------------------- userload
		} elsif ($userinput =~ /^userload/) { # client only
		    if(isClient) {
			my $userloadpercent=&userload();
			print $client "$userloadpercent\n";
		    } else {
			Reply($client, "refused\n", $userinput);
		     
		    }
#
#        Transactions requiring encryption:
#
# ----------------------------------------------------------------- currentauth
		} elsif ($userinput =~ /^currentauth/) {
		    if (($wasenc==1)  && isClient) { # Encoded & client only.
			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 {
			Reply($client, "refused\n", $userinput);
			
		    }
#--------------------------------------------------------------------- pushfile
		} elsif($userinput =~ /^pushfile/) {	# encoded & manager.
		    if(($wasenc == 1) && isManager) {
			my $cert = GetCertificate($userinput);
			if(ValidManager($cert)) {
			    my $reply = PushFile($userinput);
			    print $client "$reply\n";
			} else {
			    print $client "refused\n";
			} 
		    } else {
			Reply($client, "refused\n", $userinput);
			
		    }
#--------------------------------------------------------------------- reinit
		} elsif($userinput =~ /^reinit/) { # Encoded and manager
		    if (($wasenc == 1) && isManager) {
			my $cert = GetCertificate($userinput);
			if(ValidManager($cert)) {
			    chomp($userinput);
			    my $reply = ReinitProcess($userinput);
			    print $client  "$reply\n";
			} else {
			    print $client "refused\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);


		    }
# ------------------------------------------------------------------------ auth
		} elsif ($userinput =~ /^auth/) { # Encoded and client only.
		    if (($wasenc==1) && isClient) {
			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') {
				&Debug("Internal auth");
				$pwdcorrect=
				    (crypt($upass,$contentpwd) eq $contentpwd);
			    } elsif ($howpwd eq 'unix') {
				&Debug("Unix auth");
				if((getpwnam($uname))[1] eq "") { #no such user!
				    $pwdcorrect = 0;
				} else {
				    $contentpwd=(getpwnam($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') {
				my $null=pack("C",0);
				unless ($upass=~/$null/) {
				    my $krb4_error = &Authen::Krb4::get_pw_in_tkt
					($uname,"",$contentpwd,'krbtgt',
					 $contentpwd,1,$upass);
				    if (!$krb4_error) {
					$pwdcorrect = 1;
				    } else { 
					$pwdcorrect=0; 
					# log error if it is not a bad password
					if ($krb4_error != 62) {
					    &logthis('krb4:'.$uname.','.$contentpwd.','.
						     &Authen::Krb4::get_err_txt($Authen::Krb4::error));
					}
				    }
				}
			    } elsif ($howpwd eq 'krb5') {
				my $null=pack("C",0);
				unless ($upass=~/$null/) {
				    my $krbclient=&Authen::Krb5::parse_name($uname.'@'.$contentpwd);
				    my $krbservice="krbtgt/".$contentpwd."\@".$contentpwd;
				    my $krbserver=&Authen::Krb5::parse_name($krbservice);
				    my $credentials=&Authen::Krb5::cc_default();
				    $credentials->initialize($krbclient);
				    my $krbreturn = 
					&Authen::Krb5::get_in_tkt_with_password(
										$krbclient,$krbserver,$upass,$credentials);
#				  unless ($krbreturn) {
#				      &logthis("Krb5 Error: ".
#					       &Authen::Krb5::error());
#				  }
				    $pwdcorrect = ($krbreturn == 1);
				} 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 $client "unknown_user\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		       
		    }
# ---------------------------------------------------------------------- passwd
		} elsif ($userinput =~ /^passwd/) { # encoded and client
		    if (($wasenc==1) && isClient) {
			my 
			    ($cmd,$udom,$uname,$upass,$npass)=split(/:/,$userinput);
			chomp($npass);
			$upass=&unescape($upass);
			$npass=&unescape($npass);
			&Debug("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 ($howpwd eq 'internal') {
				&Debug("internal auth");
				if (crypt($upass,$contentpwd) eq $contentpwd) {
				    my $salt=time;
				    $salt=substr($salt,6,2);
				    my $ncpass=crypt($npass,$salt);
				    {
					my $pf;
					if ($pf = IO::File->new(">$passfilename")) {
					    print $pf "internal:$ncpass\n";
					    &logthis("Result of password change for $uname: pwchange_success");
					    print $client "ok\n";
					} else {
					    &logthis("Unable to open $uname passwd to change password");
					    print $client "non_authorized\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
				&Debug("auth is unix");
				$contentpwd=(getpwnam($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;
				    &Debug("exited pwauth with $? ($uname,$upass) ");
				    $pwdcorrect=($? == 0);
				}
				if ($pwdcorrect) {
				    my $execdir=$perlvar{'lonDaemons'};
				    &Debug("Opening lcpasswd pipeline");
				    my $pf = IO::File->new("|$execdir/lcpasswd > $perlvar{'lonDaemons'}/logs/lcpasswd.log");
				    print $pf "$uname\n$npass\n$npass\n";
				    close $pf;
				    my $err = $?;
				    my $result = ($err>0 ? 'pwchange_failure' 
						  : 'ok');
				    &logthis("Result of password change for $uname: ".
					     &lcpasswdstrerror($?));
				    print $client "$result\n";
				} else {
				    print $client "non_authorized\n";
				}
			    } else {
				print $client "auth_mode_error\n";
			    }  
			} else {
			    print $client "unknown_user\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		       
		    }
# -------------------------------------------------------------------- makeuser
		} elsif ($userinput =~ /^makeuser/) { # encoded and client.
		    &Debug("Make user received");
		    my $oldumask=umask(0077);
		    if (($wasenc==1) && isClient) {
			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 $currentdomainid) {
			    print $client "not_right_domain\n";
			} else {
			    my @fpparts=split(/\//,$proname);
			    my $fpnow=$fpparts[0].'/'.$fpparts[1].'/'.$fpparts[2];
			    my $fperror='';
			    for (my $i=3;$i<=$#fpparts;$i++) {
				$fpnow.='/'.$fpparts[$i]; 
				unless (-e $fpnow) {
				    unless (mkdir($fpnow,0777)) {
					$fperror="error: ".($!+0)
					    ." mkdir failed while attempting "
					    ."makeuser\n";
				    }
				}
			    }
			    unless ($fperror) {
				my $result=&make_passwd_file($uname, $umode,$npass,
							     $passfilename);
				print $client $result;
			    } else {
				print $client "$fperror\n";
			    }
			}
		    } else {
			Reply($client, "refused\n", $userinput);
	      
		    }
		    umask($oldumask);
# -------------------------------------------------------------- changeuserauth
		} elsif ($userinput =~ /^changeuserauth/) { # encoded & client
		    &Debug("Changing authorization");
		    if (($wasenc==1) && isClient) {
			my 
			    ($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 $currentdomainid) {
			    print $client "not_right_domain\n";
			} else {
			    my $result=&make_passwd_file($uname, $umode,$npass,
							 $passfilename);
			    print $client $result;
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		   
		    }
# ------------------------------------------------------------------------ home
		} elsif ($userinput =~ /^home/) { # client clear or encoded
		    if(isClient) {
			my ($cmd,$udom,$uname)=split(/:/,$userinput);
			chomp($uname);
			my $proname=propath($udom,$uname);
			if (-e $proname) {
			    print $client "found\n";
			} else {
			    print $client "not_found\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);

		    }
# ---------------------------------------------------------------------- update
		} elsif ($userinput =~ /^update/) { # client clear or encoded.
		    if(isClient) {
			my ($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);
				my $now=time;
				my $since=$now-$atime;
				if ($since>$perlvar{'lonExpire'}) {
				    my $reply=
					&reply("unsub:$fname","$clientname");
				    unlink("$fname");
				} else {
				    my $transname="$fname.in.transfer";
				    my $remoteurl=
					&reply("sub:$fname","$clientname");
				    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 $client "rejected\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);

		    }
# -------------------------------------- fetch a user file from a remote server
		} elsif ($userinput =~ /^fetchuserfile/) { # Client clear or enc.
		    if(isClient) {
			my ($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 $destname=$udir.'/'.$ufile;
			    my $transname=$udir.'/'.$ufile.'.in.transit';
			    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 $client "failed\n";
			    } else {
				if (!rename($transname,$destname)) {
				    &logthis("Unable to move $transname to $destname");
				    unlink($transname);
				    print $client "failed\n";
				} else {
				    print $client "ok\n";
				}
			    }
			} else {
			    print $client "not_home\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);

		    }
# ------------------------------------------ authenticate access to a user file
		} elsif ($userinput =~ /^tokenauthuserfile/) { # Client only
		    if(isClient) {
			my ($cmd,$fname,$session)=split(/:/,$userinput);
			chomp($session);
			my $reply='non_auth';
			if (open(ENVIN,$perlvar{'lonIDsDir'}.'/'.
				 $session.'.id')) {
			    while (my $line=<ENVIN>) {
				if ($line=~/userfile\.$fname\=/) { $reply='ok'; }
			    }
			    close(ENVIN);
			    print $client $reply."\n";
			} else {
			    print $client "invalid_token\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);

		    }
# ----------------------------------------------------------------- unsubscribe
		} elsif ($userinput =~ /^unsub/) {
		    if(isClient) {
			my ($cmd,$fname)=split(/:/,$userinput);
			if (-e $fname) {
			    print $client &unsub($client,$fname,$clientip);
			} else {
			    print $client "not_found\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);

		    }
# ------------------------------------------------------------------- subscribe
		} elsif ($userinput =~ /^sub/) {
		    if(isClient) {
			print $client &subscribe($userinput,$clientip);
		    } else {
			Reply($client, "refused\n", $userinput);

		    }
# ------------------------------------------------------------- current version
		} elsif ($userinput =~ /^currentversion/) {
		    if(isClient) {
			my ($cmd,$fname)=split(/:/,$userinput);
			print $client &currentversion($fname)."\n";
		    } else {
			Reply($client, "refused\n", $userinput);

		    }
# ------------------------------------------------------------------------- log
		} elsif ($userinput =~ /^log/) {
		    if(isClient) {
			my ($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:$clientname:$what\n";
				print $client "ok\n"; 
			    } else {
				print $client "error: ".($!+0)
				    ." IO::File->new Failed "
				    ."while attempting log\n";
			    }
			}
		    } else {
			Reply($client, "refused\n", $userinput);

		    }
# ------------------------------------------------------------------------- put
		} elsif ($userinput =~ /^put/) {
		    if(isClient) {
			my ($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);
			    my %hash;
			    if (tie(%hash,'GDBM_File',
				    "$proname/$namespace.db",
				    &GDBM_WRCREAT(),0640)) {
				foreach my $pair (@pairs) {
				    my ($key,$value)=split(/=/,$pair);
				    $hash{$key}=$value;
				}
				if (untie(%hash)) {
				    print $client "ok\n";
				} else {
				    print $client "error: ".($!+0)
					." untie(GDBM) failed ".
					"while attempting put\n";
				}
			    } else {
				print $client "error: ".($!)
				    ." tie(GDBM) Failed ".
				    "while attempting put\n";
			    }
			} else {
			    print $client "refused\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);

		    }
# ------------------------------------------------------------------- inc
		} elsif ($userinput =~ /^inc:/) {
		    if(isClient) {
			my ($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);
			    my %hash;
			    if (tie(%hash,'GDBM_File',
				    "$proname/$namespace.db",
				    &GDBM_WRCREAT(),0640)) {
				foreach my $pair (@pairs) {
				    my ($key,$value)=split(/=/,$pair);
                                    # We could check that we have a number...
                                    if (! defined($value) || $value eq '') {
                                        $value = 1;
                                    }
				    $hash{$key}+=$value;
				}
				if (untie(%hash)) {
				    print $client "ok\n";
				} else {
				    print $client "error: ".($!+0)
					." untie(GDBM) failed ".
					"while attempting put\n";
				}
			    } else {
				print $client "error: ".($!)
				    ." tie(GDBM) Failed ".
				    "while attempting put\n";
			    }
			} else {
			    print $client "refused\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);

		    }
# -------------------------------------------------------------------- rolesput
		} elsif ($userinput =~ /^rolesput/) {
		    if(isClient) {
			&Debug("rolesput");
			if ($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);
			    my %hash;
			    if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_WRCREAT(),0640)) {
				foreach my $pair (@pairs) {
				    my ($key,$value)=split(/=/,$pair);
				    &ManagePermissions($key, $udom, $uname,
						       &GetAuthType( $udom, 
								     $uname));
				    $hash{$key}=$value;
				}
				if (untie(%hash)) {
				    print $client "ok\n";
				} else {
				    print $client "error: ".($!+0)
					." untie(GDBM) Failed ".
					"while attempting rolesput\n";
				}
			    } else {
				print $client "error: ".($!+0)
				    ." tie(GDBM) Failed ".
				    "while attempting rolesput\n";
			    }
			} else {
			    print $client "refused\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		  
		    }
# -------------------------------------------------------------------- rolesdel
		} elsif ($userinput =~ /^rolesdel/) {
		    if(isClient) {
			&Debug("rolesdel");
			if ($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 $hfh "D:$now:$exedom:$exeuser:$what\n";
				}
			    }
			    my @rolekeys=split(/\&/,$what);
			    my %hash;
			    if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_WRCREAT(),0640)) {
				foreach my $key (@rolekeys) {
				    delete $hash{$key};
				}
				if (untie(%hash)) {
				    print $client "ok\n";
				} else {
				    print $client "error: ".($!+0)
					." untie(GDBM) Failed ".
					"while attempting rolesdel\n";
				}
			    } else {
				print $client "error: ".($!+0)
				    ." tie(GDBM) Failed ".
				    "while attempting rolesdel\n";
			    }
			} else {
			    print $client "refused\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		      
		    }
# ------------------------------------------------------------------------- get
		} elsif ($userinput =~ /^get/) {
		    if(isClient) {
			my ($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 $qresult='';
			my %hash;
			if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER(),0640)) {
			    for (my $i=0;$i<=$#queries;$i++) {
				$qresult.="$hash{$queries[$i]}&";
			    }
			    if (untie(%hash)) {
				$qresult=~s/\&$//;
				print $client "$qresult\n";
			    } else {
				print $client "error: ".($!+0)
				    ." untie(GDBM) Failed ".
				    "while attempting get\n";
			    }
			} else {
			    if ($!+0 == 2) {
				print $client "error:No such file or ".
				    "GDBM reported bad block error\n";
			    } else {
				print $client "error: ".($!+0)
				    ." tie(GDBM) Failed ".
				    "while attempting get\n";
			    }
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		       
		    }
# ------------------------------------------------------------------------ eget
		} elsif ($userinput =~ /^eget/) {
		    if (isClient) {
			my ($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 $qresult='';
			my %hash;
			if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER(),0640)) {
			    for (my $i=0;$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 $client "error: ".($!+0)
				    ." untie(GDBM) Failed ".
				    "while attempting eget\n";
			    }
			} else {
			    print $client "error: ".($!+0)
				." tie(GDBM) Failed ".
				"while attempting eget\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		    
		    }
# ------------------------------------------------------------------------- del
		} elsif ($userinput =~ /^del/) {
		    if(isClient) {
			my ($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);
			my %hash;
			if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_WRCREAT(),0640)) {
			    foreach my $key (@keys) {
				delete($hash{$key});
			    }
			    if (untie(%hash)) {
				print $client "ok\n";
			    } else {
				print $client "error: ".($!+0)
				    ." untie(GDBM) Failed ".
				    "while attempting del\n";
			    }
			} else {
			    print $client "error: ".($!+0)
				." tie(GDBM) Failed ".
				"while attempting del\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
			
		    }
# ------------------------------------------------------------------------ keys
		} elsif ($userinput =~ /^keys/) {
		    if(isClient) {
			my ($cmd,$udom,$uname,$namespace)
			    =split(/:/,$userinput);
			$namespace=~s/\//\_/g;
			$namespace=~s/\W//g;
			my $proname=propath($udom,$uname);
			my $qresult='';
			my %hash;
			if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER(),0640)) {
			    foreach my $key (keys %hash) {
				$qresult.="$key&";
			    }
			    if (untie(%hash)) {
				$qresult=~s/\&$//;
				print $client "$qresult\n";
			    } else {
				print $client "error: ".($!+0)
				    ." untie(GDBM) Failed ".
				    "while attempting keys\n";
			    }
			} else {
			    print $client "error: ".($!+0)
				." tie(GDBM) Failed ".
				"while attempting keys\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		   
		    }
# ----------------------------------------------------------------- dumpcurrent
		} elsif ($userinput =~ /^currentdump/) {
		    if (isClient) {
			my ($cmd,$udom,$uname,$namespace)
			    =split(/:/,$userinput);
			$namespace=~s/\//\_/g;
			$namespace=~s/\W//g;
			my $qresult='';
			my $proname=propath($udom,$uname);
			my %hash;
			if (tie(%hash,'GDBM_File',
				"$proname/$namespace.db",
				&GDBM_READER(),0640)) {
			    # Structure of %data:
			    # $data{$symb}->{$parameter}=$value;
			    # $data{$symb}->{'v.'.$parameter}=$version;
			    # since $parameter will be unescaped, we do not
			    # have to worry about silly parameter names...
			    my %data = ();
			    while (my ($key,$value) = each(%hash)) {
				my ($v,$symb,$param) = split(/:/,$key);
				next if ($v eq 'version' || $symb eq 'keys');
				next if (exists($data{$symb}) && 
					 exists($data{$symb}->{$param}) &&
					 $data{$symb}->{'v.'.$param} > $v);
				$data{$symb}->{$param}=$value;
				$data{$symb}->{'v.'.$param}=$v;
			    }
			    if (untie(%hash)) {
				while (my ($symb,$param_hash) = each(%data)) {
				    while(my ($param,$value) = each (%$param_hash)){
					next if ($param =~ /^v\./);
					$qresult.=$symb.':'.$param.'='.$value.'&';
				    }
				}
				chop($qresult);
				print $client "$qresult\n";
			    } else {
				print $client "error: ".($!+0)
				    ." untie(GDBM) Failed ".
				    "while attempting currentdump\n";
			    }
			} else {
			    print $client "error: ".($!+0)
				." tie(GDBM) Failed ".
				"while attempting currentdump\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		    }
# ------------------------------------------------------------------------ dump
		} elsif ($userinput =~ /^dump/) {
		    if(isClient) {
			my ($cmd,$udom,$uname,$namespace,$regexp)
			    =split(/:/,$userinput);
			$namespace=~s/\//\_/g;
			$namespace=~s/\W//g;
			if (defined($regexp)) {
			    $regexp=&unescape($regexp);
			} else {
			    $regexp='.';
			}
			my $qresult='';
			my $proname=propath($udom,$uname);
			my %hash;
			if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER(),0640)) {
			       study($regexp);
			       while (my ($key,$value) = each(%hash)) {
				   if ($regexp eq '.') {
				       $qresult.=$key.'='.$value.'&';
				   } else {
				       my $unescapeKey = &unescape($key);
				       if (eval('$unescapeKey=~/$regexp/')) {
					   $qresult.="$key=$value&";
				       }
				   }
			       }
			       if (untie(%hash)) {
				   chop($qresult);
				   print $client "$qresult\n";
			       } else {
				   print $client "error: ".($!+0)
				       ." untie(GDBM) Failed ".
                                       "while attempting dump\n";
			       }
			   } else {
			       print $client "error: ".($!+0)
				   ." tie(GDBM) Failed ".
				   "while attempting dump\n";
			   }
		    } else {
			Reply($client, "refused\n", $userinput);
		 
		    }
# ----------------------------------------------------------------------- store
		} elsif ($userinput =~ /^store/) {
		    if(isClient) {
			my ($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(/\&/,$what);
			    my %hash;
			    if (tie(%hash,'GDBM_File',"$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 my $pair (@pairs) {
				    my ($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 $client "error: ".($!+0)
					." untie(GDBM) Failed ".
					"while attempting store\n";
				}
			    } else {
				print $client "error: ".($!+0)
				    ." tie(GDBM) Failed ".
				    "while attempting store\n";
			    }
			} else {
			    print $client "refused\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		     
		    }
# --------------------------------------------------------------------- restore
		} elsif ($userinput =~ /^restore/) {
		    if(isClient) {
			my ($cmd,$udom,$uname,$namespace,$rid)
			    =split(/:/,$userinput);
			$namespace=~s/\//\_/g;
			$namespace=~s/\W//g;
			chomp($rid);
			my $proname=propath($udom,$uname);
			my $qresult='';
			my %hash;
			if (tie(%hash,'GDBM_File',"$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 $client "error: ".($!+0)
				    ." untie(GDBM) Failed ".
				    "while attempting restore\n";
			    }
			} else {
			    print $client "error: ".($!+0)
				." tie(GDBM) Failed ".
				"while attempting restore\n";
			}
		    } else  {
			Reply($client, "refused\n", $userinput);
		       
		    }
# -------------------------------------------------------------------- chatsend
		} elsif ($userinput =~ /^chatsend/) {
		    if(isClient) {
			my ($cmd,$cdom,$cnum,$newpost)=split(/\:/,$userinput);
			&chatadd($cdom,$cnum,$newpost);
			print $client "ok\n";
		    } else {
			Reply($client, "refused\n", $userinput);
		      
		    }
# -------------------------------------------------------------------- chatretr
		} elsif ($userinput =~ /^chatretr/) {
		    if(isClient) {
			my 
			    ($cmd,$cdom,$cnum,$udom,$uname)=split(/\:/,$userinput);
			my $reply='';
			foreach (&getchat($cdom,$cnum,$udom,$uname)) {
			    $reply.=&escape($_).':';
			}
			$reply=~s/\:$//;
			print $client $reply."\n";
		    } else {
			Reply($client, "refused\n", $userinput);
		       
		    }
# ------------------------------------------------------------------- querysend
		} elsif ($userinput =~ /^querysend/) {
		    if(isClient) {
			my ($cmd,$query,
			    $arg1,$arg2,$arg3)=split(/\:/,$userinput);
			$query=~s/\n*$//g;
			print $client "".
			    sqlreply("$clientname\&$query".
				     "\&$arg1"."\&$arg2"."\&$arg3")."\n";
		    } else {
			Reply($client, "refused\n", $userinput);
		      
		    }
# ------------------------------------------------------------------ queryreply
		} elsif ($userinput =~ /^queryreply/) {
		    if(isClient) {
			my ($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 $client "error: ".($!+0)
				." IO::File->new Failed ".
				"while attempting queryreply\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		     
		    }
# ----------------------------------------------------------------- courseidput
		} elsif ($userinput =~ /^courseidput/) {
		    if(isClient) {
			my ($cmd,$udom,$what)=split(/:/,$userinput);
			chomp($what);
			$udom=~s/\W//g;
			my $proname=
			    "$perlvar{'lonUsersDir'}/$udom/nohist_courseids";
			my $now=time;
			my @pairs=split(/\&/,$what);
			my %hash;
			if (tie(%hash,'GDBM_File',"$proname.db",&GDBM_WRCREAT(),0640)) {
			    foreach my $pair (@pairs) {
				my ($key,$value)=split(/=/,$pair);
				$hash{$key}=$value.':'.$now;
			    }
			    if (untie(%hash)) {
				print $client "ok\n";
			    } else {
				print $client "error: ".($!+0)
				    ." untie(GDBM) Failed ".
				    "while attempting courseidput\n";
			    }
			} else {
			    print $client "error: ".($!+0)
				." tie(GDBM) Failed ".
				"while attempting courseidput\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		       
		    }
# ---------------------------------------------------------------- courseiddump
		} elsif ($userinput =~ /^courseiddump/) {
		    if(isClient) {
			my ($cmd,$udom,$since,$description)
			    =split(/:/,$userinput);
			if (defined($description)) {
			    $description=&unescape($description);
			} else {
			    $description='.';
			}
			unless (defined($since)) { $since=0; }
			my $qresult='';
			my $proname=
			    "$perlvar{'lonUsersDir'}/$udom/nohist_courseids";
			my %hash;
			if (tie(%hash,'GDBM_File',"$proname.db",&GDBM_READER(),0640)) {
			    while (my ($key,$value) = each(%hash)) {
				my ($descr,$lasttime)=split(/\:/,$value);
				if ($lasttime<$since) { next; }
				if ($description eq '.') {
				    $qresult.=$key.'='.$descr.'&';
				} else {
				    my $unescapeVal = &unescape($descr);
				    if (eval('$unescapeVal=~/$description/i')) {
					$qresult.="$key=$descr&";
				    }
				}
			    }
			    if (untie(%hash)) {
				chop($qresult);
				print $client "$qresult\n";
			    } else {
				print $client "error: ".($!+0)
				    ." untie(GDBM) Failed ".
				    "while attempting courseiddump\n";
			    }
			} else {
			    print $client "error: ".($!+0)
				." tie(GDBM) Failed ".
				"while attempting courseiddump\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		       
		    }
# ----------------------------------------------------------------------- idput
		} elsif ($userinput =~ /^idput/) {
		    if(isClient) {
			my ($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);
			my %hash;
			if (tie(%hash,'GDBM_File',"$proname.db",&GDBM_WRCREAT(),0640)) {
			    foreach my $pair (@pairs) {
				my ($key,$value)=split(/=/,$pair);
				$hash{$key}=$value;
			    }
			    if (untie(%hash)) {
				print $client "ok\n";
			    } else {
				print $client "error: ".($!+0)
				    ." untie(GDBM) Failed ".
				    "while attempting idput\n";
			    }
			} else {
			    print $client "error: ".($!+0)
				." tie(GDBM) Failed ".
				"while attempting idput\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		       
		    }
# ----------------------------------------------------------------------- idget
		} elsif ($userinput =~ /^idget/) {
		    if(isClient) {
			my ($cmd,$udom,$what)=split(/:/,$userinput);
			chomp($what);
			$udom=~s/\W//g;
			my $proname="$perlvar{'lonUsersDir'}/$udom/ids";
			my @queries=split(/\&/,$what);
			my $qresult='';
			my %hash;
			if (tie(%hash,'GDBM_File',"$proname.db",&GDBM_READER(),0640)) {
			    for (my $i=0;$i<=$#queries;$i++) {
				$qresult.="$hash{$queries[$i]}&";
			    }
			    if (untie(%hash)) {
				$qresult=~s/\&$//;
				print $client "$qresult\n";
			    } else {
				print $client "error: ".($!+0)
				    ." untie(GDBM) Failed ".
				    "while attempting idget\n";
			    }
			} else {
			    print $client "error: ".($!+0)
				." tie(GDBM) Failed ".
				"while attempting idget\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		       
		    }
# ---------------------------------------------------------------------- tmpput
		} elsif ($userinput =~ /^tmpput/) {
		    if(isClient) {
			my ($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 $client "error: ".($!+0)
				."IO::File->new Failed ".
				"while attempting tmpput\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		    
		    }
		    
# ---------------------------------------------------------------------- tmpget
		} elsif ($userinput =~ /^tmpget/) {
		    if(isClient) {
			my ($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 $client "error: ".($!+0)
				."IO::File->new Failed ".
				"while attempting tmpget\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		      
		    }
# ---------------------------------------------------------------------- tmpdel
		} elsif ($userinput =~ /^tmpdel/) {
		    if(isClient) {
			my ($cmd,$id)=split(/:/,$userinput);
			chomp($id);
			$id=~s/\W/\_/g;
			my $execdir=$perlvar{'lonDaemons'};
			if (unlink("$execdir/tmp/$id.tmp")) {
			    print $client "ok\n";
			} else {
			    print $client "error: ".($!+0)
				."Unlink tmp Failed ".
				"while attempting tmpdel\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		     
		    }
# -------------------------------------------------------------------------- ls
		} elsif ($userinput =~ /^ls/) {
		    if(isClient) {
			my ($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";
		    } else {
			Reply($client, "refused\n", $userinput);
		     
		    }
# ----------------------------------------------------------------- setannounce
		} elsif ($userinput =~ /^setannounce/) {
		    if (isClient) {
			my ($cmd,$announcement)=split(/:/,$userinput);
			chomp($announcement);
			$announcement=&unescape($announcement);
			if (my $store=IO::File->new('>'.$perlvar{'lonDocRoot'}.
						    '/announcement.txt')) {
			    print $store $announcement;
			    close $store;
			    print $client "ok\n";
			} else {
			    print $client "error: ".($!+0)."\n";
			}
		    } else {
			Reply($client, "refused\n", $userinput);
		       
		    }
# ------------------------------------------------------------------ Hanging up
		} elsif (($userinput =~ /^exit/) ||
			 ($userinput =~ /^init/)) { # no restrictions.
		    &logthis(
			     "Client $clientip ($clientname) hanging up: $userinput");
		    print $client "bye\n";
		    $client->shutdown(2);        # shutdown the socket forcibly.
		    $client->close();
		    last;

# ---------------------------------- set current host/domain
		} elsif ($userinput =~ /^sethost:/) {
		    if (isClient) {
			print $client &sethost($userinput)."\n";
		    } else {
			print $client "refused\n";
		    }
#---------------------------------- request file (?) version.
		} elsif ($userinput =~/^version:/) {
		    if (isClient) {
			print $client &version($userinput)."\n";
		    } else {
			print $client "refused\n";
		    }
# ------------------------------------------------------------- unknown command

		} else {
		    # unknown command
		    print $client "unknown_cmd\n";
		}
# -------------------------------------------------------------------- complete
		alarm(0);
		&status('Listening to '.$clientname);
	    }
# --------------------------------------------- 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 $clientip ($clientname)</font>");    
    
    
    # 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
    &logthis("ruequest is $request");
    if($request =~ /^(\/$domain\/_au)$/) { # It's an author rolesput...
	my $execdir = $perlvar{'lonDaemons'};
	my $userhome= "/home/$user" ;
	&logthis("system $execdir/lchtmldir $userhome $user $authtype");
	system("$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' or $authtype eq 'krb5') {
	    $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;
    my $sh;
    if ($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,$udom,$uname)=@_;
    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;
    }
    my @participants=();
    my $cutoff=time-60;
    if (tie(%hash,'GDBM_File',"$proname/nohist_inchatroom.db",
	    &GDBM_WRCREAT(),0640)) {
        $hash{$uname.':'.$udom}=time;
        foreach (sort keys %hash) {
	    if ($hash{$_}>$cutoff) {
		$participants[$#participants+1]='active_participant:'.$_;
            }
        }
        untie %hash;
    }
    return (@participants,@entries);
}

sub chatadd {
    my ($cdom,$cname,$newchat)=@_;
    my %hash;
    my $proname=&propath($cdom,$cname);
    my @entries=();
    my $time=time;
    if (tie(%hash,'GDBM_File',"$proname/nohist_chatroom.db",
	    &GDBM_WRCREAT(),0640)) {
	@entries=map { $_.':'.$hash{$_} } sort keys %hash;
	my ($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;
    }
    {
	my $hfh;
	if ($hfh=IO::File->new(">>$proname/chatroom.log")) { 
	    print $hfh "$time:".&unescape($newchat)."\n";
	}
    }
}

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

sub currentversion {
    my $fname=shift;
    my $version=-1;
    my $ulsdir='';
    if ($fname=~/^(.+)\/[^\/]+$/) {
       $ulsdir=$1;
    }
    my ($fnamere1,$fnamere2);
    # remove version if already specified
    $fname=~s/\.\d+\.(\w+(?:\.meta)*)$/\.$1/;
    # get the bits that go before and after the version number
    if ( $fname=~/^(.*\.)(\w+(?:\.meta)*)$/ ) {
	$fnamere1=$1;
	$fnamere2='.'.$2;
    }
    if (-e $fname) { $version=1; }
    if (-e $ulsdir) {
	if(-d $ulsdir) {
	    if (opendir(LSDIR,$ulsdir)) {
		my $ulsfn;
		while ($ulsfn=readdir(LSDIR)) {
# see if this is a regular file (ignore links produced earlier)
		    my $thisfile=$ulsdir.'/'.$ulsfn;
		    unless (-l $thisfile) {
			if ($thisfile=~/\Q$fnamere1\E(\d+)\Q$fnamere2\E$/) {
			    if ($1>$version) { $version=$1; }
			}
		    }
		}
		closedir(LSDIR);
		$version++;
	    }
	}
    }
    return $version;
}

sub thisversion {
    my $fname=shift;
    my $version=-1;
    if ($fname=~/\.(\d+)\.\w+(?:\.meta)*$/) {
	$version=$1;
    }
    return $version;
}

sub subscribe {
    my ($userinput,$clientip)=@_;
    my $result;
    my ($cmd,$fname)=split(/:/,$userinput);
    my $ownership=&ishome($fname);
    if ($ownership eq 'owner') {
# explitly asking for the current version?
        unless (-e $fname) {
            my $currentversion=&currentversion($fname);
	    if (&thisversion($fname)==$currentversion) {
                if ($fname=~/^(.+)\.\d+\.(\w+(?:\.meta)*)$/) {
		    my $root=$1;
                    my $extension=$2;
                    symlink($root.'.'.$extension,
                            $root.'.'.$currentversion.'.'.$extension);
                    unless ($extension=~/\.meta$/) {
                       symlink($root.'.'.$extension.'.meta',
                            $root.'.'.$currentversion.'.'.$extension.'.meta');
		    }
                }
            }
        }
	if (-e $fname) {
	    if (-d $fname) {
		$result="directory\n";
	    } else {
		if (-e "$fname.$clientname") {&unsub($fname,$clientip);}
		my $now=time;
		my $found=&addline($fname,$clientname,$clientip,
				   "$clientname:$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;
}

sub make_passwd_file {
    my ($uname, $umode,$npass,$passfilename)=@_;
    my $result="ok\n";
    if ($umode eq 'krb4' or $umode eq 'krb5') {
	{
	    my $pf = IO::File->new(">$passfilename");
	    print $pf "$umode:$npass\n";
	}
    } elsif ($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"; 
	}
    } elsif ($umode eq 'localauth') {
	{
	    my $pf = IO::File->new(">$passfilename");
	    print $pf "localauth:$npass\n";
	}
    } elsif ($umode eq 'unix') {
	{
	    my $execpath="$perlvar{'lonDaemons'}/"."lcuseradd";
	    {
		&Debug("Executing external: ".$execpath);
		&Debug("user  = ".$uname.", Password =". $npass);
		my $se = IO::File->new("|$execpath > $perlvar{'lonDaemons'}/logs/lcuseradd.log");
		print $se "$uname\n";
		print $se "$npass\n";
		print $se "$npass\n";
	    }
	    my $useraddok = $?;
	    if($useraddok > 0) {
		&logthis("Failed lcuseradd: ".&lcuseraddstrerror($useraddok));
	    }
	    my $pf = IO::File->new(">$passfilename");
	    print $pf "unix:\n";
	}
    } elsif ($umode eq 'none') {
	{
	    my $pf = IO::File->new(">$passfilename");
	    print $pf "none:\n";
	}
    } else {
	$result="auth_mode_error\n";
    }
    return $result;
}

sub sethost {
    my ($remotereq) = @_;
    my (undef,$hostid)=split(/:/,$remotereq);
    if (!defined($hostid)) { $hostid=$perlvar{'lonHostID'}; }
    if ($hostip{$perlvar{'lonHostID'}} eq $hostip{$hostid}) {
	$currenthostid=$hostid;
	$currentdomainid=$hostdom{$hostid};
	&logthis("Setting hostid to $hostid, and domain to $currentdomainid");
    } else {
	&logthis("Requested host id $hostid not an alias of ".
		 $perlvar{'lonHostID'}." refusing connection");
	return 'unable_to_set';
    }
    return 'ok';
}

sub version {
    my ($userinput)=@_;
    $remoteVERSION=(split(/:/,$userinput))[1];
    return "version:$VERSION";
}

#There is a copy of this in lonnet.pm
sub userload {
    my $numusers=0;
    {
	opendir(LONIDS,$perlvar{'lonIDsDir'});
	my $filename;
	my $curtime=time;
	while ($filename=readdir(LONIDS)) {
	    if ($filename eq '.' || $filename eq '..') {next;}
	    my ($mtime)=(stat($perlvar{'lonIDsDir'}.'/'.$filename))[9];
	    if ($curtime-$mtime < 1800) { $numusers++; }
	}
	closedir(LONIDS);
    }
    my $userloadpercent=0;
    my $maxuserload=$perlvar{'lonUserLoadLim'};
    if ($maxuserload) {
	$userloadpercent=100*$numusers/$maxuserload;
    }
    $userloadpercent=sprintf("%.2f",$userloadpercent);
    return $userloadpercent;
}

# ----------------------------------- 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 *

SIGUSR2

Parent Signal assignment:
    $SIG{USR2} = \&UpdateHosts

Child signal assignment:
    NONE


=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 pushtable

Pushes a file in /home/httpd/lonTab directory.  Currently limited to:
hosts.tab and domain.tab. The old file is copied to  *.tab.backup but
must be restored manually in case of a problem with the new table file.
pushtable requires that the request be encrypted and validated via
ValidateManager.  The form of the command is:
enc:pushtable tablename <tablecontents> \n
where pushtable, tablename and <tablecontents> will be encrypted, but \n is a 
cleartext newline.

=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
Authen::Krb5

=head1 COREQUISITES

=head1 OSNAMES

linux

=head1 SCRIPT CATEGORIES

Server/Process

=cut

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