--- loncom/lond 1999/11/04 20:12:47 1.3
+++ loncom/lond 2002/03/03 19:49:00 1.74
@@ -1,9 +1,60 @@
#!/usr/bin/perl
# The LearningOnline Network
# lond "LON Daemon" Server (port "LOND" 5663)
+#
+# $Id: lond,v 1.74 2002/03/03 19:49:00 harris41 Exp $
+#
+# Copyright Michigan State University Board of Trustees
+#
+# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
+#
+# LON-CAPA is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# LON-CAPA is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with LON-CAPA; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+#
+# /home/httpd/html/adm/gpl.txt
+#
+# http://www.lon-capa.org/
+#
# 5/26/99,6/4,6/10,6/11,6/14,6/15,6/26,6/28,6/30,
# 7/8,7/9,7/10,7/12,7/17,7/19,9/21,
-# 10/7,10/8,10/9,10/11,10/13,10/15 Gerd Kortemeyer
+# 10/7,10/8,10/9,10/11,10/13,10/15,11/4,11/16,
+# 12/7,12/15,01/06,01/11,01/12,01/14,2/8,
+# 03/07,05/31 Gerd Kortemeyer
+# 06/26 Scott Harrison
+# 06/29,06/30,07/14,07/15,07/17,07/20,07/25,09/18 Gerd Kortemeyer
+# 12/05 Scott Harrison
+# 12/05,12/13,12/29 Gerd Kortemeyer
+# YEAR=2001
+# Jan 01 Scott Harrison
+# 02/12 Gerd Kortemeyer
+# 03/15 Scott Harrison
+# 03/24 Gerd Kortemeyer
+# 04/02 Scott Harrison
+# 05/11,05/28,08/30 Gerd Kortemeyer
+# 9/30,10/22,11/13,11/15,11/16 Scott Harrison
+# 11/26,11/27 Gerd Kortemeyer
+# 12/20 Scott Harrison
+# 12/22 Gerd Kortemeyer
+# YEAR=2002
+# 01/20/02,02/05 Gerd Kortemeyer
+# 02/05 Guy Albertelli
+# 02/07 Scott Harrison
+# 02/12 Gerd Kortemeyer
+# 02/19 Matthew Hall
+# 02/25 Gerd Kortemeyer
+###
+
# based on "Perl Cookbook" ISBN 1-56592-243-3
# preforker - server who forks first
# runs as a daemon
@@ -19,6 +70,34 @@ use Crypt::IDEA;
use LWP::UserAgent();
use GDBM_File;
use Authen::Krb4;
+use lib '/home/httpd/lib/perl/';
+use localauth;
+
+my $status='';
+my $lastlog='';
+
+# grabs exception and records it to log before exiting
+sub catchexception {
+ my ($error)=@_;
+ $SIG{'QUIT'}='DEFAULT';
+ $SIG{__DIE__}='DEFAULT';
+ &logthis("CRITICAL: "
+ ."ABNORMAL EXIT. Child $$ for server $wasserver died through "
+ ."a crash with this error msg->[$error]");
+ &logthis('Famous last words: '.$status.' - '.$lastlog);
+ if ($client) { print $client "error: $error\n"; }
+ $server->close();
+ die($error);
+}
+
+sub timeout {
+ &logthis("CRITICAL: TIME OUT ".$$."");
+ &catchexception('Timeout');
+}
+# -------------------------------- Set signal handlers to record abnormal exits
+
+$SIG{'QUIT'}=\&catchexception;
+$SIG{__DIE__}=\&catchexception;
# ------------------------------------ Read httpd access.conf and get variables
@@ -27,11 +106,33 @@ open (CONFIG,"/etc/httpd/conf/access.con
while ($configline=) {
if ($configline =~ /PerlSetVar/) {
my ($dummy,$varname,$varvalue)=split(/\s+/,$configline);
+ chomp($varvalue);
$perlvar{$varname}=$varvalue;
}
}
close(CONFIG);
+# ----------------------------- Make sure this process is running from user=www
+my $wwwid=getpwnam('www');
+if ($wwwid!=$<) {
+ $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
+ $subj="LON: $perlvar{'lonHostID'} User ID mismatch";
+ system("echo 'User ID mismatch. lond must be run as user www.' |\
+ mailto $emailto -s '$subj' > /dev/null");
+ exit 1;
+}
+
+# --------------------------------------------- Check if other instance running
+
+my $pidfile="$perlvar{'lonDaemons'}/logs/lond.pid";
+
+if (-e $pidfile) {
+ my $lfh=IO::File->new("$pidfile");
+ my $pide=<$lfh>;
+ chomp($pide);
+ if (kill 0 => $pide) { die "already running"; }
+}
+
$PREFORK=4; # number of children to maintain, at least four spare
# ------------------------------------------------------------- Read hosts file
@@ -40,7 +141,7 @@ open (CONFIG,"$perlvar{'lonTabDir'}/host
while ($configline=) {
my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
- chomp($ip);
+ chomp($ip); $ip=~s/\D+$//;
$hostid{$ip}=$id;
if ($id eq $perlvar{'lonHostID'}) { $thisserver=$name; }
$PREFORK++;
@@ -67,29 +168,61 @@ $children = 0; # cu
sub REAPER { # takes care of dead children
$SIG{CHLD} = \&REAPER;
my $pid = wait;
- $children --;
- &logthis("Child $pid died");
- delete $children{$pid};
+ if (defined($children{$pid})) {
+ &logthis("Child $pid died");
+ $children --;
+ delete $children{$pid};
+ } else {
+ &logthis("Unknown Child $pid died");
+ }
}
sub HUNTSMAN { # signal handler for SIGINT
local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
kill 'INT' => keys %children;
+ &logthis("Free socket: ".shutdown($server,2)); # free up socket
my $execdir=$perlvar{'lonDaemons'};
unlink("$execdir/logs/lond.pid");
- &logthis("Shutting down");
+ &logthis("CRITICAL: Shutting down");
exit; # clean up with dignity
}
sub HUPSMAN { # signal handler for SIGHUP
local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
kill 'INT' => keys %children;
- close($server); # free up socket
- &logthis("Restarting");
+ &logthis("Free socket: ".shutdown($server,2)); # free up socket
+ &logthis("CRITICAL: Restarting");
+ unlink("$execdir/logs/lond.pid");
my $execdir=$perlvar{'lonDaemons'};
exec("$execdir/lond"); # here we go again
}
+sub checkchildren {
+ &initnewstatus();
+ &logstatus();
+ &logthis('Going to check on the children');
+ $docdir=$perlvar{'lonDocRoot'};
+ foreach (sort keys %children) {
+ sleep 1;
+ unless (kill 'USR1' => $_) {
+ &logthis ('Child '.$_.' is dead');
+ &logstatus($$.' is dead');
+ }
+ }
+ sleep 5;
+ foreach (sort keys %children) {
+ unless (-e "$docdir/lon-status/londchld/$_.txt") {
+ &logthis('Child '.$_.' did not respond');
+ kill 9 => $_;
+ $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
+ $subj="LON: $perlvar{'lonHostID'} killed lond process $_";
+ my $result=`echo 'Killed lond process $_.' | mailto $emailto -s '$subj' > /dev/null`;
+ $execdir=$perlvar{'lonDaemons'};
+ $result=`/bin/cp $execdir/logs/lond.log $execdir/logs/lond.log.$_`
+ }
+ }
+}
+
# --------------------------------------------------------------------- Logging
sub logthis {
@@ -98,9 +231,64 @@ sub logthis {
my $fh=IO::File->new(">>$execdir/logs/lond.log");
my $now=time;
my $local=localtime($now);
+ $lastlog=$local.': '.$message;
print $fh "$local ($$): $message\n";
}
+# ------------------------------------------------------------------ Log status
+
+sub logstatus {
+ my $docdir=$perlvar{'lonDocRoot'};
+ {
+ my $fh=IO::File->new(">>$docdir/lon-status/londstatus.txt");
+ print $fh $$."\t".$status."\t".$lastlog."\n";
+ $fh->close();
+ }
+ {
+ my $fh=IO::File->new(">$docdir/lon-status/londchld/$$.txt");
+ print $fh $status."\n".$lastlog."\n".time;
+ $fh->close();
+ }
+}
+
+sub initnewstatus {
+ my $docdir=$perlvar{'lonDocRoot'};
+ my $fh=IO::File->new(">$docdir/lon-status/londstatus.txt");
+ my $now=time;
+ my $local=localtime($now);
+ print $fh "LOND status $local - parent $$\n\n";
+ opendir(DIR,"$docdir/lon-status/londchld");
+ while ($filename=readdir(DIR)) {
+ unlink("$docdir/lon-status/londchld/$filename");
+ }
+ closedir(DIR);
+}
+
+# -------------------------------------------------------------- Status setting
+
+sub status {
+ my $what=shift;
+ my $now=time;
+ my $local=localtime($now);
+ $status=$local.': '.$what;
+}
+
+# -------------------------------------------------------- Escape Special Chars
+
+sub escape {
+ my $str=shift;
+ $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
+ return $str;
+}
+
+# ----------------------------------------------------- Un-Escape Special Chars
+
+sub unescape {
+ my $str=shift;
+ $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
+ return $str;
+}
+
# ----------------------------------------------------------- Send USR1 to lonc
sub reconlonc {
@@ -118,16 +306,20 @@ sub reconlonc {
&logthis("$peerfile still not there, give it another try");
sleep 5;
if (-e "$peerfile") { return; }
- &logthis("$peerfile still not there, giving up");
+ &logthis(
+ "WARNING: $peerfile still not there, giving up");
} else {
- &logthis("lonc at pid $loncpid not responding, giving up");
+ &logthis(
+ "CRITICAL: "
+ ."lonc at pid $loncpid not responding, giving up");
}
} else {
- &logthis('lonc not running, giving up');
+ &logthis('CRITICAL: lonc not running, giving up');
}
}
# -------------------------------------------------- Non-critical communication
+
sub subreply {
my ($cmd,$server)=@_;
my $peerfile="$perlvar{'lonSockDir'}/$server";
@@ -160,18 +352,44 @@ sub 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;
+ 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/;
@@ -199,7 +417,8 @@ $execdir=$perlvar{'lonDaemons'};
open (PIDSAVE,">$execdir/logs/lond.pid");
print PIDSAVE "$$\n";
close(PIDSAVE);
-&logthis("Starting");
+&logthis("CRITICAL: ---------- Starting ----------");
+&status('Starting');
# ------------------------------------------------------- Now we are on our own
@@ -210,13 +429,19 @@ for (1 .. $PREFORK) {
# ----------------------------------------------------- Install signal handlers
+&status('Forked children');
+
$SIG{CHLD} = \&REAPER;
$SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
$SIG{HUP} = \&HUPSMAN;
+$SIG{USR1} = \&checkchildren;
# And maintain the population.
while (1) {
+ &status('Sleeping');
sleep; # wait for a signal (i.e., child's death)
+ &logthis('Woke up');
+ &status('Woke up');
for ($i = $children; $i < $PREFORK; $i++) {
make_new_child(); # top up the child pool
}
@@ -240,19 +465,27 @@ sub make_new_child {
or die "Can't unblock SIGINT for fork: $!\n";
$children{$pid} = 1;
$children++;
+ &status('Started child '.$pid);
return;
} else {
# Child can *not* return from this subroutine.
$SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
-
+ $SIG{USR1}= \&logstatus;
+ $SIG{ALRM}= \&timeout;
+ $lastlog='Forked ';
+ $status='Forked';
+
# unblock signals
sigprocmask(SIG_UNBLOCK, $sigset)
or die "Can't unblock SIGINT for fork: $!\n";
+
+ $tmpsnum=0;
# handle connections until we've reached $MAX_CLIENTS_PER_CHILD
for ($i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
+ &status('Idle, waiting for connection');
$client = $server->accept() or last;
-
+ &status('Accepted connection');
# =============================================================================
# do something with the connection
# -----------------------------------------------------------------------------
@@ -261,35 +494,53 @@ sub make_new_child {
my ($port,$iaddr)=unpack_sockaddr_in($caller);
my $clientip=inet_ntoa($iaddr);
my $clientrec=($hostid{$clientip} ne undef);
- &logthis("Connect from $clientip ($hostid{$clientip})");
+ &logthis(
+"INFO: Connection $i, $clientip ($hostid{$clientip})"
+ );
+ &status("Connecting $clientip ($hostid{$clientip})");
my $clientok;
if ($clientrec) {
+ &status("Waiting for init from $clientip ($hostid{$clientip})");
my $remotereq=<$client>;
$remotereq=~s/\W//g;
if ($remotereq eq 'init') {
my $challenge="$$".time;
print $client "$challenge\n";
+ &status(
+ "Waiting for challenge reply from $clientip ($hostid{$clientip})");
$remotereq=<$client>;
$remotereq=~s/\W//g;
if ($challenge eq $remotereq) {
$clientok=1;
print $client "ok\n";
} else {
- &logthis("$clientip did not reply challenge");
+ &logthis(
+ "WARNING: $clientip did not reply challenge");
+ &status('No challenge reply '.$clientip);
}
} else {
- &logthis("$clientip failed to initialize: >$remotereq<");
+ &logthis(
+ "WARNING: "
+ ."$clientip failed to initialize: >$remotereq< ");
+ &status('No init '.$clientip);
}
} else {
- &logthis("Unknown client $clientip");
+ &logthis(
+ "WARNING: Unknown client $clientip");
+ &status('Hung up on '.$clientip);
}
if ($clientok) {
# ---------------- New known client connecting, could mean machine online again
&reconlonc("$perlvar{'lonSockDir'}/$hostid{$clientip}");
+ &logthis(
+ "Established connection: $hostid{$clientip}");
+ &status('Will listen to '.$hostid{$clientip});
# ------------------------------------------------------------ Process requests
while (my $userinput=<$client>) {
chomp($userinput);
+ &status('Processing '.$hostid{$clientip}.': '.$userinput);
my $wasenc=0;
+ alarm(120);
# ------------------------------------------------------------ See if encrypted
if ($userinput =~ /^enc/) {
if ($cipher) {
@@ -337,11 +588,34 @@ sub make_new_child {
$loadavg =~ s/\s.*//g;
my $loadpercent=100*$loadavg/$perlvar{'lonLoadLim'};
print $client "$loadpercent\n";
+# ----------------------------------------------------------------- currentauth
+ } elsif ($userinput =~ /^currentauth/) {
+ if ($wasenc==1) {
+ my ($cmd,$udom,$uname)=split(/:/,$userinput);
+ my $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 $availablecontent='';
+ if ($howpwd eq 'krb4') {
+ $availablecontent=$contentpwd;
+ }
+ print $client "$howpwd:$availablecontent\n";
+ } else {
+ print $client "unknown_user\n";
+ }
+ } else {
+ print $client "refused\n";
+ }
# ------------------------------------------------------------------------ auth
} elsif ($userinput =~ /^auth/) {
if ($wasenc==1) {
my ($cmd,$udom,$uname,$upass)=split(/:/,$userinput);
chomp($upass);
+ $upass=unescape($upass);
my $proname=propath($udom,$uname);
my $passfilename="$proname/passwd";
if (-e $passfilename) {
@@ -355,14 +629,30 @@ sub make_new_child {
(crypt($upass,$contentpwd) eq $contentpwd);
} elsif ($howpwd eq 'unix') {
$contentpwd=(getpwnam($uname))[1];
- $pwdcorrect=
- (crypt($upass,$contentpwd) eq $contentpwd);
+ my $pwauth_path="/usr/local/sbin/pwauth";
+ unless ($contentpwd eq 'x') {
+ $pwdcorrect=
+ (crypt($upass,$contentpwd) eq $contentpwd);
+ }
+ elsif (-e $pwauth_path) {
+ open PWAUTH, "|$pwauth_path" or
+ die "Cannot invoke authentication";
+ print PWAUTH "$uname\n$upass\n";
+ close PWAUTH;
+ $pwdcorrect=!$?;
+ }
} elsif ($howpwd eq 'krb4') {
+ $null=pack("C",0);
+ unless ($upass=~/$null/) {
$pwdcorrect=(
Authen::Krb4::get_pw_in_tkt($uname,"",
$contentpwd,'krbtgt',$contentpwd,1,
$upass) == 0);
- }
+ } else { $pwdcorrect=0; }
+ } elsif ($howpwd eq 'localauth') {
+ $pwdcorrect=&localauth::localauth($uname,$upass,
+ $contentpwd);
+ }
if ($pwdcorrect) {
print $client "authorized\n";
} else {
@@ -380,7 +670,10 @@ sub make_new_child {
my
($cmd,$udom,$uname,$upass,$npass)=split(/:/,$userinput);
chomp($npass);
- my $proname=propath($udom,$uname);
+ $upass=&unescape($upass);
+ $npass=&unescape($npass);
+ &logthis("Trying to change password for $uname");
+ my $proname=propath($udom,$uname);
my $passfilename="$proname/passwd";
if (-e $passfilename) {
my $realpasswd;
@@ -394,12 +687,43 @@ sub make_new_child {
$salt=substr($salt,6,2);
my $ncpass=crypt($npass,$salt);
{ my $pf = IO::File->new(">$passfilename");
- print $pf "internal:$ncpass\n";; }
+ print $pf "internal:$ncpass\n"; }
+ &logthis("Result of password change for $uname: pwchange_success");
print $client "ok\n";
} else {
print $client "non_authorized\n";
}
- } else {
+ } elsif ($howpwd eq 'unix') {
+ # Unix means we have to access /etc/password
+ # one way or another.
+ # First: Make sure the current password is
+ # correct
+ $contentpwd=(getpwnam($uname))[1];
+ my $pwdcorrect = "0";
+ my $pwauth_path="/usr/local/sbin/pwauth";
+ unless ($contentpwd eq 'x') {
+ $pwdcorrect=
+ (crypt($upass,$contentpwd) eq $contentpwd);
+ } elsif (-e $pwauth_path) {
+ open PWAUTH, "|$pwauth_path" or
+ die "Cannot invoke authentication";
+ print PWAUTH "$uname\n$upass\n";
+ close PWAUTH;
+ $pwdcorrect=!$?;
+ }
+ if ($pwdcorrect) {
+ my $execdir=$perlvar{'lonDaemons'};
+ my $pf = IO::File->new("|$execdir/lcpasswd");
+ print $pf "$uname\n$npass\n$npass\n";
+ close $pf;
+ my $result = ($?>0 ? 'pwchange_failure'
+ : 'ok');
+ &logthis("Result of password change for $uname: $result");
+ print $client "$result\n";
+ } else {
+ print $client "non_authorized\n";
+ }
+ } else {
print $client "auth_mode_error\n";
}
} else {
@@ -408,6 +732,145 @@ sub make_new_child {
} else {
print $client "refused\n";
}
+# -------------------------------------------------------------------- makeuser
+ } elsif ($userinput =~ /^makeuser/) {
+ my $oldumask=umask(0077);
+ if ($wasenc==1) {
+ my
+ ($cmd,$udom,$uname,$umode,$npass)=split(/:/,$userinput);
+ chomp($npass);
+ $npass=&unescape($npass);
+ my $proname=propath($udom,$uname);
+ my $passfilename="$proname/passwd";
+ if (-e $passfilename) {
+ print $client "already_exists\n";
+ } elsif ($udom ne $perlvar{'lonDefDomain'}) {
+ print $client "not_right_domain\n";
+ } else {
+ @fpparts=split(/\//,$proname);
+ $fpnow=$fpparts[0].'/'.$fpparts[1].'/'.$fpparts[2];
+ $fperror='';
+ for ($i=3;$i<=$#fpparts;$i++) {
+ $fpnow.='/'.$fpparts[$i];
+ unless (-e $fpnow) {
+ unless (mkdir($fpnow,0777)) {
+ $fperror="error:$!";
+ }
+ }
+ }
+ unless ($fperror) {
+ if ($umode eq 'krb4') {
+ {
+ my $pf = IO::File->new(">$passfilename");
+ print $pf "krb4:$npass\n";
+ }
+ print $client "ok\n";
+ } elsif ($umode eq 'internal') {
+ my $salt=time;
+ $salt=substr($salt,6,2);
+ my $ncpass=crypt($npass,$salt);
+ {
+ my $pf = IO::File->new(">$passfilename");
+ print $pf "internal:$ncpass\n";
+ }
+ print $client "ok\n";
+ } elsif ($umode eq 'localauth') {
+ {
+ my $pf = IO::File->new(">$passfilename");
+ print $pf "localauth:$npass\n";
+ }
+ print $client "ok\n";
+ } elsif ($umode eq 'unix') {
+ {
+ my $execpath="$perlvar{'lonDaemons'}/".
+ "lcuseradd";
+ {
+ my $se = IO::File->new("|$execpath");
+ print $se "$uname\n";
+ print $se "$npass\n";
+ print $se "$npass\n";
+ }
+ my $pf = IO::File->new(">$passfilename");
+ print $pf "unix:\n";
+ }
+ print $client "ok\n";
+ } elsif ($umode eq 'none') {
+ {
+ my $pf = IO::File->new(">$passfilename");
+ print $pf "none:\n";
+ }
+ print $client "ok\n";
+ } else {
+ print $client "auth_mode_error\n";
+ }
+ } else {
+ print $client "$fperror\n";
+ }
+ }
+ } else {
+ print $client "refused\n";
+ }
+ umask($oldumask);
+# -------------------------------------------------------------- changeuserauth
+ } elsif ($userinput =~ /^changeuserauth/) {
+ if ($wasenc==1) {
+ my
+ ($cmd,$udom,$uname,$umode,$npass)=split(/:/,$userinput);
+ chomp($npass);
+ $npass=&unescape($npass);
+ my $proname=propath($udom,$uname);
+ my $passfilename="$proname/passwd";
+ if ($udom ne $perlvar{'lonDefDomain'}) {
+ print $client "not_right_domain\n";
+ } else {
+ if ($umode eq 'krb4') {
+ {
+ my $pf = IO::File->new(">$passfilename");
+ print $pf "krb4:$npass\n";
+ }
+ print $client "ok\n";
+ } elsif ($umode eq 'internal') {
+ my $salt=time;
+ $salt=substr($salt,6,2);
+ my $ncpass=crypt($npass,$salt);
+ {
+ my $pf = IO::File->new(">$passfilename");
+ print $pf "internal:$ncpass\n";
+ }
+ print $client "ok\n";
+ } elsif ($umode eq 'localauth') {
+ {
+ my $pf = IO::File->new(">$passfilename");
+ print $pf "localauth:$npass\n";
+ }
+ print $client "ok\n";
+ } elsif ($umode eq 'unix') {
+ {
+ my $execpath="$perlvar{'lonDaemons'}/".
+ "lcuseradd";
+ {
+ my $se = IO::File->new("|$execpath");
+ print $se "$uname\n";
+ print $se "$npass\n";
+ print $se "$npass\n";
+ }
+ my $pf = IO::File->new(">$passfilename");
+ print $pf "unix:\n";
+ }
+ print $client "ok\n";
+ } elsif ($umode eq 'none') {
+ {
+ my $pf = IO::File->new(">$passfilename");
+ print $pf "none:\n";
+ }
+ print $client "ok\n";
+ } else {
+ print $client "auth_mode_error\n";
+ }
+ }
+ } else {
+ print $client "refused\n";
+ }
# ------------------------------------------------------------------------ home
} elsif ($userinput =~ /^home/) {
my ($cmd,$udom,$uname)=split(/:/,$userinput);
@@ -445,11 +908,21 @@ sub make_new_child {
$response=$ua->request($request,$transname);
}
if ($response->is_error()) {
- unline($transname);
+ 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);
}
}
@@ -478,41 +951,102 @@ sub make_new_child {
my $ownership=ishome($fname);
if ($ownership eq 'owner') {
if (-e $fname) {
+ if (-d $fname) {
+ print $client "directory\n";
+ } else {
$now=time;
{
- my $sh=IO::File->new(">$fname.$hostid{$clientip}");
- print $sh "$clientip:$now\n";
+ my $sh;
+ if ($sh=
+ IO::File->new(">$fname.$hostid{$clientip}")) {
+ print $sh "$clientip:$now\n";
+ }
}
+ unless ($fname=~/\.meta$/) {
+ unlink("$fname.meta.$hostid{$clientip}");
+ }
$fname=~s/\/home\/httpd\/html\/res/raw/;
$fname="http://$thisserver/".$fname;
print $client "$fname\n";
+ }
} else {
print $client "not_found\n";
}
} else {
print $client "rejected\n";
}
+# ------------------------------------------------------------------------- log
+ } elsif ($userinput =~ /^log/) {
+ my ($cmd,$udom,$uname,$what)=split(/:/,$userinput);
+ chomp($what);
+ my $proname=propath($udom,$uname);
+ my $now=time;
+ {
+ my $hfh;
+ if ($hfh=IO::File->new(">>$proname/activity.log")) {
+ print $hfh "$now:$hostid{$clientip}:$what\n";
+ print $client "ok\n";
+ } else {
+ print $client "error:$!\n";
+ }
+ }
# ------------------------------------------------------------------------- put
} elsif ($userinput =~ /^put/) {
- my ($cmd,$udom,$uname,$namespace,$what)
+ my ($cmd,$udom,$uname,$namespace,$what)
=split(/:/,$userinput);
- $namespace=~s/\W//g;
+ $namespace=~s/\//\_/g;
+ $namespace=~s/\W//g;
+ if ($namespace ne 'roles') {
chomp($what);
my $proname=propath($udom,$uname);
my $now=time;
- {
+ unless ($namespace=~/^nohist\_/) {
my $hfh;
if (
$hfh=IO::File->new(">>$proname/$namespace.hist")
) { print $hfh "P:$now:$what\n"; }
}
my @pairs=split(/\&/,$what);
- if (dbmopen(%hash,"$proname/$namespace.db",0644)) {
+ if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_WRCREAT,0640)) {
+ foreach $pair (@pairs) {
+ ($key,$value)=split(/=/,$pair);
+ $hash{$key}=$value;
+ }
+ if (untie(%hash)) {
+ print $client "ok\n";
+ } else {
+ print $client "error:$!\n";
+ }
+ } else {
+ print $client "error:$!\n";
+ }
+ } else {
+ print $client "refused\n";
+ }
+# -------------------------------------------------------------------- rolesput
+ } elsif ($userinput =~ /^rolesput/) {
+ if ($wasenc==1) {
+ my ($cmd,$exedom,$exeuser,$udom,$uname,$what)
+ =split(/:/,$userinput);
+ my $namespace='roles';
+ chomp($what);
+ my $proname=propath($udom,$uname);
+ my $now=time;
+ {
+ my $hfh;
+ if (
+ $hfh=IO::File->new(">>$proname/$namespace.hist")
+ ) {
+ print $hfh "P:$now:$exedom:$exeuser:$what\n";
+ }
+ }
+ my @pairs=split(/\&/,$what);
+ if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_WRCREAT,0640)) {
foreach $pair (@pairs) {
($key,$value)=split(/=/,$pair);
$hash{$key}=$value;
}
- if (dbmclose(%hash)) {
+ if (untie(%hash)) {
print $client "ok\n";
} else {
print $client "error:$!\n";
@@ -520,20 +1054,24 @@ sub make_new_child {
} else {
print $client "error:$!\n";
}
+ } else {
+ print $client "refused\n";
+ }
# ------------------------------------------------------------------------- get
} elsif ($userinput =~ /^get/) {
my ($cmd,$udom,$uname,$namespace,$what)
=split(/:/,$userinput);
+ $namespace=~s/\//\_/g;
$namespace=~s/\W//g;
chomp($what);
my @queries=split(/\&/,$what);
my $proname=propath($udom,$uname);
my $qresult='';
- if (dbmopen(%hash,"$proname/$namespace.db",0644)) {
+ if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER,0640)) {
for ($i=0;$i<=$#queries;$i++) {
$qresult.="$hash{$queries[$i]}&";
}
- if (dbmclose(%hash)) {
+ if (untie(%hash)) {
$qresult=~s/\&$//;
print $client "$qresult\n";
} else {
@@ -546,16 +1084,17 @@ sub make_new_child {
} elsif ($userinput =~ /^eget/) {
my ($cmd,$udom,$uname,$namespace,$what)
=split(/:/,$userinput);
+ $namespace=~s/\//\_/g;
$namespace=~s/\W//g;
chomp($what);
my @queries=split(/\&/,$what);
my $proname=propath($udom,$uname);
my $qresult='';
- if (dbmopen(%hash,"$proname/$namespace.db",0644)) {
+ if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER,0640)) {
for ($i=0;$i<=$#queries;$i++) {
$qresult.="$hash{$queries[$i]}&";
}
- if (dbmclose(%hash)) {
+ if (untie(%hash)) {
$qresult=~s/\&$//;
if ($cipher) {
my $cmdlength=length($qresult);
@@ -581,22 +1120,23 @@ sub make_new_child {
} elsif ($userinput =~ /^del/) {
my ($cmd,$udom,$uname,$namespace,$what)
=split(/:/,$userinput);
+ $namespace=~s/\//\_/g;
$namespace=~s/\W//g;
chomp($what);
my $proname=propath($udom,$uname);
my $now=time;
- {
+ unless ($namespace=~/^nohist\_/) {
my $hfh;
if (
$hfh=IO::File->new(">>$proname/$namespace.hist")
) { print $hfh "D:$now:$what\n"; }
}
my @keys=split(/\&/,$what);
- if (dbmopen(%hash,"$proname/$namespace.db",0644)) {
+ if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_WRCREAT,0640)) {
foreach $key (@keys) {
delete($hash{$key});
}
- if (dbmclose(%hash)) {
+ if (untie(%hash)) {
print $client "ok\n";
} else {
print $client "error:$!\n";
@@ -608,15 +1148,15 @@ sub make_new_child {
} elsif ($userinput =~ /^keys/) {
my ($cmd,$udom,$uname,$namespace)
=split(/:/,$userinput);
+ $namespace=~s/\//\_/g;
$namespace=~s/\W//g;
- chomp($namespace);
my $proname=propath($udom,$uname);
my $qresult='';
- if (dbmopen(%hash,"$proname/$namespace.db",0644)) {
+ if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER,0640)) {
foreach $key (keys %hash) {
$qresult.="$key&";
}
- if (dbmclose(%hash)) {
+ if (untie(%hash)) {
$qresult=~s/\&$//;
print $client "$qresult\n";
} else {
@@ -627,17 +1167,24 @@ sub make_new_child {
}
# ------------------------------------------------------------------------ dump
} elsif ($userinput =~ /^dump/) {
- my ($cmd,$udom,$uname,$namespace)
+ my ($cmd,$udom,$uname,$namespace,$regexp)
=split(/:/,$userinput);
+ $namespace=~s/\//\_/g;
$namespace=~s/\W//g;
- chomp($namespace);
+ if (defined($regexp)) {
+ $regexp=&unescape($regexp);
+ } else {
+ $regexp='.';
+ }
my $proname=propath($udom,$uname);
my $qresult='';
- if (dbmopen(%hash,"$proname/$namespace.db",0644)) {
+ if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER,0640)) {
foreach $key (keys %hash) {
- $qresult.="$key=$hash{$key}&";
+ if (eval('$key=~/$regexp/')) {
+ $qresult.="$key=$hash{$key}&";
+ }
}
- if (dbmclose(%hash)) {
+ if (untie(%hash)) {
$qresult=~s/\&$//;
print $client "$qresult\n";
} else {
@@ -646,6 +1193,111 @@ sub make_new_child {
} else {
print $client "error:$!\n";
}
+# ----------------------------------------------------------------------- store
+ } elsif ($userinput =~ /^store/) {
+ my ($cmd,$udom,$uname,$namespace,$rid,$what)
+ =split(/:/,$userinput);
+ $namespace=~s/\//\_/g;
+ $namespace=~s/\W//g;
+ if ($namespace ne 'roles') {
+ chomp($what);
+ my $proname=propath($udom,$uname);
+ my $now=time;
+ unless ($namespace=~/^nohist\_/) {
+ my $hfh;
+ if (
+ $hfh=IO::File->new(">>$proname/$namespace.hist")
+ ) { print $hfh "P:$now:$rid:$what\n"; }
+ }
+ my @pairs=split(/\&/,$what);
+
+ if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_WRCREAT,0640)) {
+ my @previouskeys=split(/&/,$hash{"keys:$rid"});
+ my $key;
+ $hash{"version:$rid"}++;
+ my $version=$hash{"version:$rid"};
+ my $allkeys='';
+ foreach $pair (@pairs) {
+ ($key,$value)=split(/=/,$pair);
+ $allkeys.=$key.':';
+ $hash{"$version:$rid:$key"}=$value;
+ }
+ $hash{"$version:$rid:timestamp"}=$now;
+ $allkeys.='timestamp';
+ $hash{"$version:keys:$rid"}=$allkeys;
+ if (untie(%hash)) {
+ print $client "ok\n";
+ } else {
+ print $client "error:$!\n";
+ }
+ } else {
+ print $client "error:$!\n";
+ }
+ } else {
+ print $client "refused\n";
+ }
+# --------------------------------------------------------------------- restore
+ } elsif ($userinput =~ /^restore/) {
+ my ($cmd,$udom,$uname,$namespace,$rid)
+ =split(/:/,$userinput);
+ $namespace=~s/\//\_/g;
+ $namespace=~s/\W//g;
+ chomp($rid);
+ my $proname=propath($udom,$uname);
+ my $qresult='';
+ if (tie(%hash,'GDBM_File',"$proname/$namespace.db",&GDBM_READER,0640)) {
+ my $version=$hash{"version:$rid"};
+ $qresult.="version=$version&";
+ my $scope;
+ for ($scope=1;$scope<=$version;$scope++) {
+ my $vkeys=$hash{"$scope:keys:$rid"};
+ my @keys=split(/:/,$vkeys);
+ my $key;
+ $qresult.="$scope:keys=$vkeys&";
+ foreach $key (@keys) {
+ $qresult.="$scope:$key=".$hash{"$scope:$rid:$key"}."&";
+ }
+ }
+ if (untie(%hash)) {
+ $qresult=~s/\&$//;
+ print $client "$qresult\n";
+ } else {
+ print $client "error:$!\n";
+ }
+ } else {
+ print $client "error:$!\n";
+ }
+# ------------------------------------------------------------------- querysend
+ } elsif ($userinput =~ /^querysend/) {
+ my ($cmd,$query,
+ $custom,$customshow)=split(/:/,$userinput);
+ $query=~s/\n*$//g;
+ unless ($custom or $customshow) {
+ print $client "".
+ sqlreply("$hostid{$clientip}\&$query")."\n";
+ }
+ else {
+ print $client "".
+ sqlreply("$hostid{$clientip}\&$query".
+ "\&$custom"."\&$customshow")."\n";
+ }
+# ------------------------------------------------------------------ queryreply
+ } elsif ($userinput =~ /^queryreply/) {
+ my ($cmd,$id,$reply)=split(/:/,$userinput);
+ my $store;
+ my $execdir=$perlvar{'lonDaemons'};
+ if ($store=IO::File->new(">$execdir/tmp/$id")) {
+ $reply=~s/\&/\n/g;
+ print $store $reply;
+ close $store;
+ my $store2=IO::File->new(">$execdir/tmp/$id.end");
+ print $store2 "done\n";
+ close $store2;
+ print $client "ok\n";
+ }
+ else {
+ print $client "error:$!\n";
+ }
# ----------------------------------------------------------------------- idput
} elsif ($userinput =~ /^idput/) {
my ($cmd,$udom,$what)=split(/:/,$userinput);
@@ -660,12 +1312,12 @@ sub make_new_child {
) { print $hfh "P:$now:$what\n"; }
}
my @pairs=split(/\&/,$what);
- if (dbmopen(%hash,"$proname.db",0644)) {
+ if (tie(%hash,'GDBM_File',"$proname.db",&GDBM_WRCREAT,0640)) {
foreach $pair (@pairs) {
($key,$value)=split(/=/,$pair);
$hash{$key}=$value;
}
- if (dbmclose(%hash)) {
+ if (untie(%hash)) {
print $client "ok\n";
} else {
print $client "error:$!\n";
@@ -681,11 +1333,11 @@ sub make_new_child {
my $proname="$perlvar{'lonUsersDir'}/$udom/ids";
my @queries=split(/\&/,$what);
my $qresult='';
- if (dbmopen(%hash,"$proname.db",0644)) {
+ if (tie(%hash,'GDBM_File',"$proname.db",&GDBM_READER,0640)) {
for ($i=0;$i<=$#queries;$i++) {
$qresult.="$hash{$queries[$i]}&";
}
- if (dbmclose(%hash)) {
+ if (untie(%hash)) {
$qresult=~s/\&$//;
print $client "$qresult\n";
} else {
@@ -694,23 +1346,91 @@ sub make_new_child {
} else {
print $client "error:$!\n";
}
+# ---------------------------------------------------------------------- tmpput
+ } elsif ($userinput =~ /^tmpput/) {
+ my ($cmd,$what)=split(/:/,$userinput);
+ my $store;
+ $tmpsnum++;
+ my $id=$$.'_'.$clientip.'_'.$tmpsnum;
+ $id=~s/\W/\_/g;
+ $what=~s/\n//g;
+ my $execdir=$perlvar{'lonDaemons'};
+ if ($store=IO::File->new(">$execdir/tmp/$id.tmp")) {
+ print $store $what;
+ close $store;
+ print $client "$id\n";
+ }
+ else {
+ print $client "error:$!\n";
+ }
+
+# ---------------------------------------------------------------------- tmpget
+ } elsif ($userinput =~ /^tmpget/) {
+ my ($cmd,$id)=split(/:/,$userinput);
+ chomp($id);
+ $id=~s/\W/\_/g;
+ my $store;
+ my $execdir=$perlvar{'lonDaemons'};
+ if ($store=IO::File->new("$execdir/tmp/$id.tmp")) {
+ my $reply=<$store>;
+ print $client "$reply\n";
+ close $store;
+ }
+ else {
+ print $client "error:$!\n";
+ }
+
+# -------------------------------------------------------------------------- ls
+ } elsif ($userinput =~ /^ls/) {
+ my ($cmd,$ulsdir)=split(/:/,$userinput);
+ my $ulsout='';
+ my $ulsfn;
+ if (-e $ulsdir) {
+ if (opendir(LSDIR,$ulsdir)) {
+ while ($ulsfn=readdir(LSDIR)) {
+ my @ulsstats=stat($ulsdir.'/'.$ulsfn);
+ $ulsout.=$ulsfn.'&'.join('&',@ulsstats).':';
+ }
+ closedir(LSDIR);
+ }
+ } else {
+ $ulsout='no_such_dir';
+ }
+ if ($ulsout eq '') { $ulsout='empty'; }
+ print $client "$ulsout\n";
+# ------------------------------------------------------------------ Hanging up
+ } elsif (($userinput =~ /^exit/) ||
+ ($userinput =~ /^init/)) {
+ &logthis(
+ "Client $clientip ($hostid{$clientip}) hanging up: $userinput");
+ print $client "bye\n";
+ $client->close();
+ last;
# ------------------------------------------------------------- unknown command
} else {
# unknown command
print $client "unknown_cmd\n";
}
-# ------------------------------------------------------ client unknown, refuse
+# -------------------------------------------------------------------- complete
+ alarm(0);
+ &status('Listening to '.$hostid{$clientip});
}
+# --------------------------------------------- client unknown or fishy, refuse
} else {
print $client "refused\n";
- &logthis("Rejected client $clientip, closing connection");
+ $client->close();
+ &logthis("WARNING: "
+ ."Rejected client $clientip, closing connection");
}
- &logthis("Disconnect from $clientip ($hostid{$clientip})");
+ &logthis("CRITICAL: "
+ ."Disconnect from $clientip ($hostid{$clientip})");
# =============================================================================
}
# tidy up gracefully and finish
+ $server->close();
+
# this exit is VERY important, otherwise the child will become
# a producer of more and more children, forking yourself into
# process death.
@@ -718,7 +1438,313 @@ sub make_new_child {
}
}
+# ----------------------------------- POD (plain old documentation, CPAN style)
+
+=head1 NAME
+
+lond - "LON Daemon" Server (port "LOND" 5663)
+
+=head1 SYNOPSIS
+
+Usage: B
+
+Should only be run as user=www. This is a command-line script which
+is invoked by B. There is no expectation that a typical user
+will manually start B from the command-line. (In other words,
+DO NOT START B YOURSELF.)
+
+=head1 DESCRIPTION
+
+There are two characteristics associated with the running of B,
+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
+
+Preforker - server who forks first. Runs as a daemon. HUPs.
+Uses IDEA encryption
+
+B 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 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
+
+This is the process id number of the parent B 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 B<-s> SIGTERM I
+ B B<-s> SIGINT I
+
+Subroutine B:
+ This is only invoked for the B parent I.
+This kills all the children, and then the parent.
+The B 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 B<-s> SIGHUP I
+
+Subroutine B:
+ This is only invoked for the B parent I,
+This kills all the children, and then the parent.
+The B file is cleared.
+
+=item *
+
+SIGUSR1
+
+Parent signal assignment:
+ $SIG{USR1} = \&USRMAN;
+
+Child signal assignment:
+ $SIG{USR1}= \&logstatus;
+
+Command-line invocations:
+ B B<-s> SIGUSR1 I
+
+Subroutine B:
+ When invoked for the B parent I,
+SIGUSR1 is sent to all the children, and the status of
+each connection is logged.
+
+=item *
+
+SIGCHLD
+
+Parent signal assignment:
+ $SIG{CHLD} = \&REAPER;
+
+Child signal assignment:
+ none
+
+Command-line invocations:
+ B B<-s> SIGCHLD I
+
+Subroutine B:
+ This is only invoked for the B parent I.
+Information pertaining to the child is removed.
+The socket port is cleaned up.
+
+=back
+
+B
+
+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
+
+=item put
+
+stores hash in namespace
+
+=item rolesput
+
+put a role into a user's environment
+
+=item get
+
+returns hash with keys from array
+reference filled in from namespace
+
+=item eget
+
+returns hash with keys from array
+reference filled in from namesp (encrypts the return communication)
+
+=item rolesget
+
+get a role from a user's environment
+
+=item del
+
+deletes keys out of array from namespace
+
+=item keys
+
+returns namespace keys
+
+=item dump
+
+dumps the complete (or key matching regexp) namespace into a hash
+
+=item store
+
+stores hash permanently
+for this url; hashref needs to be given and should be a \%hashname; the
+remaining args aren't required and if they aren't passed or are '' they will
+be derived from the ENV
+
+=item restore
+
+returns a hash for a given url
+
+=item querysend
+
+Tells client about the lonsql process that has been launched in response
+to a sent query.
+
+=item queryreply
+
+Accept information from lonsql and make appropriate storage in temporary
+file space.
+
+=item idput
+
+Defines usernames as corresponding to IDs. (These "IDs" are unique identifiers
+for each student, defined perhaps by the institutional Registrar.)
+
+=item idget
+
+Returns usernames corresponding to IDs. (These "IDs" are unique identifiers
+for each student, defined perhaps by the institutional Registrar.)
+
+=item tmpput
+
+Accept and store information in temporary space.
+
+=item tmpget
+
+Send along temporarily stored information.
+
+=item ls
+
+List part of a user's directory.
+
+=item Hanging up (exit or init)
+
+What to do when a client tells the server that they (the client)
+are leaving the network.
+
+=item unknown command
+
+If B is sent an unknown command (not in the list above),
+it replys to the client "unknown_cmd".
+
+=item UNKNOWN CLIENT
+
+If the anti-spoofing algorithm cannot verify the client,
+the client is rejected (with a "refused" message sent
+to the client, and the connection is closed.
+
+=back
+
+=head1 PREREQUISITES
+
+IO::Socket
+IO::File
+Apache::File
+Symbol
+POSIX
+Crypt::IDEA
+LWP::UserAgent()
+GDBM_File
+Authen::Krb4
+
+=head1 COREQUISITES
+
+=head1 OSNAMES
+linux
+=head1 SCRIPT CATEGORIES
+Server/Process
+=cut