--- loncom/auth/lonlogin.pm	2018/12/02 14:55:59	1.175
+++ loncom/auth/lonlogin.pm	2018/12/05 03:29:05	1.176
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Login Screen
 #
-# $Id: lonlogin.pm,v 1.175 2018/12/02 14:55:59 raeburn Exp $
+# $Id: lonlogin.pm,v 1.176 2018/12/05 03:29:05 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -37,7 +37,7 @@ use Apache::lonauth();
 use Apache::lonlocal;
 use Apache::migrateuser();
 use lib '/home/httpd/lib/perl/';
-use LONCAPA;
+use LONCAPA qw(:DEFAULT :match);
 use CGI::Cookie();
  
 sub handler {
@@ -47,7 +47,7 @@ sub handler {
 	(join('&',$ENV{'QUERY_STRING'},$env{'request.querystring'},
 	      $ENV{'REDIRECT_QUERY_STRING'}),
 	 ['interface','username','domain','firsturl','localpath','localres',
-	  'token','role','symb','iptoken']);
+	  'token','role','symb','iptoken','btoken']);
     if (!defined($env{'form.firsturl'})) {
         &Apache::lonacc::get_posted_cgi($r,['firsturl']);
     }
@@ -64,10 +64,10 @@ sub handler {
 
 # For "public user" - remove any exising "public" cookie, as user really wants to log-in
     my ($handle,$lonidsdir,$expirepub,$userdom);
+    $lonidsdir=$r->dir_config('lonIDsDir');
     unless ($r->header_only) {
         $handle = &Apache::lonnet::check_for_valid_session($r,'lonID',undef,\$userdom);
         if ($handle ne '') {
-            $lonidsdir=$r->dir_config('lonIDsDir');
             if ($handle=~/^publicuser\_/) {
                 unlink($r->dir_config('lonIDsDir')."/$handle.id");
                 undef($handle);
@@ -106,6 +106,7 @@ sub handler {
 	return OK;
     }
 
+    my $lonhost = $r->dir_config('lonHostID');
     $env{'form.firsturl'} =~ s/(`)/'/g;
 
 # Check if browser sent a LON-CAPA load balancer cookie (and this is a balancer)
@@ -120,6 +121,13 @@ sub handler {
             if ($env{'form.firsturl'} ne '') {
                 $dest = $env{'form.firsturl'};
             }
+            my %info = (
+                         balcookie => $lonhost.':'.$balancer_cookie,
+                       );
+            my $balancer_token = &Apache::lonnet::tmpput(\%info,$found_server);
+            if ($balancer_token) {
+                $dest .=  (($dest=~/\?/)?'&;':'?') . 'btoken='.$balancer_token;
+            }
             my $url = $protocol.'://'.$hostname.$dest;
             my $start_page =
                 &Apache::loncommon::start_page('Switching Server ...',undef,
@@ -131,6 +139,19 @@ sub handler {
     }
 
 #
+# Check if a LON-CAPA load balancer sent user here because user's browser sent
+# it a balancer cookie for an active session on this server.
+#
+
+    my $balcookie;
+    if ($env{'form.btoken'}) {
+        my %info = &Apache::lonnet::tmpget($env{'form.btoken'});
+        $balcookie = $info{'balcookie'};
+        &Apache::lonnet::tmpdel($env{'form.btoken'});
+        delete($env{'form.btoken'});
+    }
+
+#
 # If browser sent an old cookie for which the session file had been removed
 # check if configuration for user's domain has a portal URL set.  If so
 # switch user's log-in to the portal.
@@ -156,7 +177,7 @@ sub handler {
 	    &Apache::loncommon::end_page();
         my $dest = '/adm/roles';
         if ($env{'form.firsturl'} ne '') {
-            $dest = $env{'form.firsturl'}; 
+            $dest = $env{'form.firsturl'};
         }
 	$r->print(
                   $start_page
@@ -194,12 +215,11 @@ sub handler {
     my $iconpath= 
 	&Apache::loncommon::lonhttpdurl($r->dir_config('lonIconsURL'));
 
-    my $lonhost = $r->dir_config('lonHostID');
     my $domain = &Apache::lonnet::default_login_domain();
     my $defdom = $domain;
     if ($lonhost ne '') {
         unless ($sessiondata{'sessionserver'}) {
-            my $redirect = &check_loginvia($domain,$lonhost);
+            my $redirect = &check_loginvia($domain,$lonhost,$lonidsdir,$balcookie);
             if ($redirect) {
                 $r->print($redirect);
                 return OK;
@@ -707,8 +727,8 @@ ENDDOCUMENT
 }
 
 sub check_loginvia {
-    my ($domain,$lonhost) = @_;
-    if ($domain eq '' || $lonhost eq '') {
+    my ($domain,$lonhost,$lonidsdir,$balcookie) = @_;
+    if ($domain eq '' || $lonhost eq '' || $lonidsdir eq '') {
         return;
     }
     my %domconfhash = &Apache::loncommon::get_domainconf($domain);
@@ -737,6 +757,36 @@ sub check_loginvia {
             }
             if ($newhost ne $lonhost) {
                 if (&Apache::lonnet::hostname($newhost) ne '') {
+                    if ($balcookie) {
+                        my ($balancer,$cookie) = split(/:/,$balcookie);
+                        if ($cookie =~ /^($match_domain)_($match_username)_([a-f0-9]+)$/) {
+                            my ($udom,$uname,$cookieid) = ($1,$2,$3);
+                            unless (&Apache::lonnet::delbalcookie($cookie,$balancer) eq 'ok') {
+                                if ((-d $lonidsdir) && (opendir(my $dh,$lonidsdir))) {
+                                    while (my $filename=readdir($dh)) {
+                                        if ($filename=~/^(\Q$uname\E_\d+_\Q$udom\E_$match_lonid)\.id$/) {
+                                            my $handle = $1;
+                                            my %hash =
+                                                &Apache::lonnet::get_sessionfile_vars($handle,$lonidsdir,
+                                                                                     ['request.balancercookie',
+                                                                                      'user.linkedenv']);
+                                            if ($hash{'request.balancercookie'} eq "$balancer:$cookieid") {
+                                                if (unlink("$lonidsdir/$filename")) {
+                                                    if (($hash{'user.linkedenv'} =~ /^[a-f0-9]+_linked$/) &&
+                                                        (-l "$lonidsdir/$hash{'user.linkedenv'}.id") &&
+                                                        (readlink("$lonidsdir/$hash{'user.linkedenv'}.id") eq "$lonidsdir/$filename")) {
+                                                        unlink("$lonidsdir/$hash{'user.linkedenv'}.id");
+                                                    }
+                                                }
+                                            }
+                                            last;
+                                        }
+                                    }
+                                    closedir($dh);
+                                }
+                            }
+                        }
+                    }
                     $output = &redirect_page($newhost,$path);
                 }
             }