--- loncom/auth/lonauth.pm	2000/11/10 10:08:24	1.17
+++ loncom/auth/lonauth.pm	2001/01/09 22:10:40	1.18
@@ -7,6 +7,7 @@
 
 package Apache::lonauth;
 
+use strict;
 use Apache::Constants qw(:common);
 use Apache::File;
 use CGI qw(:standard);
@@ -14,7 +15,7 @@ use CGI::Cookie();
 use Crypt::DES;
 use Apache::lonnet();
 use Apache::lonmenu();
-
+use Fcntl qw(:flock);
 # ------------------------------------------------------------ Successful login
 
 sub success {
@@ -88,6 +89,12 @@ sub success {
 
        {
 	    my $idf=Apache::File->new(">$lonids/$cookie.id");
+	    unless (flock($idf,LOCK_EX)) {
+	      &Apache::lonnet::logthis("<font color=blue>WARNING: ".
+				       'Could not obtain exclusive lock in lonauth: '.$!);
+	      $idf->close();
+	      return 'error: '.$!;
+	    }
             if ($userenv ne '') { print $idf "$userenv\n"; }
             print $idf "user.name=$username\n";
             print $idf "user.domain=$domain\n";
@@ -102,6 +109,7 @@ sub success {
             print $idf "request.role=cm\n";
             print $idf "request.host=$ENV{'HTTP_HOST'}\n"; 
             if ($userroles ne '') { print $idf "$userroles"; }
+	    $idf->close();
         }
 
 # -------------------------------------------------------------------- Log this