--- loncom/auth/lonauth.pm	2003/09/20 17:44:22	1.57
+++ loncom/auth/lonauth.pm	2003/11/12 16:55:40	1.59
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # User Authentication Module
 #
-# $Id: lonauth.pm,v 1.57 2003/09/20 17:44:22 www Exp $
+# $Id: lonauth.pm,v 1.59 2003/11/12 16:55:40 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -191,6 +191,12 @@ Content-type: text/html
 Set-cookie: $cookie
 
 ENDHEADER
+    my %lt=&Apache::lonlocal::texthash(
+				       'wel' => 'Welcome',
+				       'mes' => 'Welcome to the Learning<i>Online</i> Network with CAPA. Please wait while your session is being set up',
+				       'pro' => 'Problems',
+				       'log' => 'loginproblems.html',
+				       );
     $r->print(<<ENDSUCCESS);
 <html>
 <head>
@@ -200,11 +206,9 @@ $startupremote
 $bodytag
 $setflags
 $windowinfo
-<h1>Welcome!</h1>
-Welcome to the Learning<i>Online</i> Network with CAPA.
-Please wait while your session
-is being set up.<p>
-<a href="/adm/loginproblems.html">Problems?</a></p>
+<h1>$lt{'wel'}</h1>
+$lt{'mes'}.<p>
+<a href="/adm/$lt{'log'}">$lt{'pro'}?</a></p>
 $maincall
 </body>
 </html>
@@ -273,6 +277,43 @@ sub handler {
 
     &Apache::lonlocal::get_language_handle($r);
 
+# -------------------------------- Prevent users from attempting to login twice
+    my %cookies=CGI::Cookie->parse($r->header_in('Cookie'));
+    my $lonid=$cookies{'lonID'};
+    my $cookie;
+    if ($lonid) {
+	my $handle=$lonid->value;
+        $handle=~s/\W//g;
+        my $lonidsdir=$r->dir_config('lonIDsDir');
+        if ((-e "$lonidsdir/$handle.id") && ($handle ne '')) {
+# Indeed, a valid token is found
+	    $r->send_cgi_header(<<ENDFHEADER);
+Content-type: text/html
+
+ENDFHEADER
+	    my $bodytag=&Apache::loncommon::bodytag('Already logged in');
+	    $r->print(<<ENDFAILED);
+<html>
+<head>
+<title>Already logged in</title>
+</head>
+<html>
+$bodytag
+<h1>You are already logged in</h1>
+<p>Please either <a href="/adm/roles">continue the current session</a> or
+<a href="/adm/logout">logout</a>.</p>
+<p>
+<a href="/adm/loginproblems.html">Problems?</a></p>
+</body>
+</html>
+ENDFAILED
+           return OK;
+	}
+    }
+
+# ---------------------------------------------------- No valid token, continue
+
+
     my $buffer;
     $r->read($buffer,$r->header_in('Content-length'),0);
     my @pairs=split(/&/,$buffer);
@@ -343,7 +384,8 @@ sub handler {
         return OK;
     }
 
-    if (($firsturl eq '') || ($firsturl eq '/adm/logout')) {
+    if (($firsturl eq '') || 
+	($firsturl=~/^\/adm\/(logout|remote)/)) {
 	$firsturl='/adm/roles';
     }
 
