--- loncom/lonnet/perl/lonnet.pm	2018/08/07 17:12:25	1.1380
+++ loncom/lonnet/perl/lonnet.pm	2018/12/08 15:17:25	1.1394
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.1380 2018/08/07 17:12:25 raeburn Exp $
+# $Id: lonnet.pm,v 1.1394 2018/12/08 15:17:25 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -73,7 +73,7 @@ package Apache::lonnet;
 use strict;
 use HTTP::Date;
 use Image::Magick;
-
+use CGI::Cookie;
 
 use Encode;
 
@@ -230,12 +230,19 @@ sub get_server_distarch {
 }
 
 sub get_servercerts_info {
-    my ($lonhost,$context) = @_;
+    my ($lonhost,$hostname,$context) = @_;
+    return if ($lonhost eq '');
+    if ($hostname eq '') {
+        $hostname = &hostname($lonhost);
+    }
+    return if ($hostname eq '');
     my ($rep,$uselocal);
-    if (grep { $_ eq $lonhost } &current_machine_ids()) {
+    if ($context eq 'install') {
+        $uselocal = 1;
+    } elsif (grep { $_ eq $lonhost } &current_machine_ids()) {
         $uselocal = 1;
     }
-    if (($context ne 'cgi') && ($uselocal)) {
+    if (($context ne 'cgi') && ($context ne 'install') && ($uselocal)) {
         my $distro = (split(/\:/,&get_server_distarch($lonhost)))[0];
         if ($distro eq '') {
             $uselocal = 0;
@@ -250,16 +257,11 @@ sub get_servercerts_info {
         }
     }
     if ($uselocal) {
-        $rep = LONCAPA::Lond::server_certs(\%perlvar);
+        $rep = LONCAPA::Lond::server_certs(\%perlvar,$lonhost,$hostname);
     } else {
         $rep=&reply('servercerts',$lonhost);
     }
     my ($result,%returnhash);
-    if (defined($lonhost)) {
-        if (!defined(&hostname($lonhost))) {
-            return;
-        }
-    }
     if (($rep=~/^(refused|rejected|error)/) || ($rep eq 'con_lost') ||
         ($rep eq 'unknown_cmd')) {
         $result = $rep;
@@ -709,6 +711,7 @@ sub check_for_valid_session {
 
     if (!defined($disk_env{'user.name'})
 	|| !defined($disk_env{'user.domain'})) {
+        untie(%disk_env);
 	return undef;
     }
 
@@ -721,6 +724,7 @@ sub check_for_valid_session {
             $userhashref->{'ltiuri'} = $disk_env{'request.lti.uri'};
         }
     }
+    untie(%disk_env);
 
     return $handle;
 }
@@ -745,6 +749,37 @@ sub timed_flock {
     }
 }
 
+sub get_sessionfile_vars {
+    my ($handle,$lonidsdir,$storearr) = @_;
+    my %returnhash;
+    unless (ref($storearr) eq 'ARRAY') {
+        return %returnhash;
+    }
+    if (-l "$lonidsdir/$handle.id") {
+        my $link = readlink("$lonidsdir/$handle.id");
+        if ((-e $link) && ($link =~ m{^\Q$lonidsdir\E/(.+)\.id$})) {
+            $handle = $1;
+        }
+    }
+    if ((-e "$lonidsdir/$handle.id") &&
+        ($handle =~ /^($match_username)\_\d+\_($match_domain)\_(.+)$/)) {
+        my ($possuname,$possudom,$possuhome) = ($1,$2,$3);
+        if ((&domain($possudom) ne '') && (&homeserver($possuname,$possudom) eq $possuhome)) {
+            if (open(my $idf,'+<',"$lonidsdir/$handle.id")) {
+                flock($idf,LOCK_SH);
+                if (tie(my %disk_env,'GDBM_File',"$lonidsdir/$handle.id",
+                        &GDBM_READER(),0640)) {
+                    foreach my $item (@{$storearr}) {
+                        $returnhash{$item} = $disk_env{$item};
+                    }
+                    untie(%disk_env);
+                }
+            }
+        }
+    }
+    return %returnhash;
+}
+
 # ---------------------------------------------------------- Append Environment
 
 sub appenv {
@@ -898,6 +933,7 @@ sub userload {
 	while ($filename=readdir(LONIDS)) {
 	    next if ($filename eq '.' || $filename eq '..');
 	    next if ($filename =~ /publicuser_\d+\.id/);
+            next if ($filename =~ /^[a-f0-9]+_linked\.id$/);
 	    my ($mtime)=(stat($perlvar{'lonIDsDir'}.'/'.$filename))[9];
 	    if ($curtime-$mtime < 1800) { $numusers++; }
 	}
@@ -1026,6 +1062,75 @@ sub find_existing_session {
     return;
 }
 
+# check if user's browser sent load balancer cookie and server still has session
+# and is not overloaded.
+sub check_for_balancer_cookie {
+    my ($r,$update_mtime) = @_;
+    my ($otherserver,$cookie);
+    my %cookies=CGI::Cookie->parse($r->header_in('Cookie'));
+    if (exists($cookies{'balanceID'})) {
+        my $balid = $cookies{'balanceID'};
+        $cookie=&LONCAPA::clean_handle($balid->value);
+        my $balancedir=$r->dir_config('lonBalanceDir');
+        if ((-d $balancedir) && (-e "$balancedir/$cookie.id")) {
+            if ($cookie =~ /^($match_domain)_($match_username)_[a-f0-9]+$/) {
+                my ($possudom,$possuname) = ($1,$2);
+                my $has_session = 0;
+                if ((&domain($possudom) ne '') &&
+                    (&homeserver($possuname,$possudom) ne 'no_host')) {
+                    my $try_server;
+                    my $opened = open(my $idf,'+<',"$balancedir/$cookie.id");
+                    if ($opened) {
+                        flock($idf,LOCK_SH);
+                        while (my $line = <$idf>) {
+                            chomp($line);
+                            if (&hostname($line) ne '') {
+                                $try_server = $line;
+                                last;
+                            }
+                        }
+                        close($idf);
+                        if (($try_server) &&
+                            (&has_user_session($try_server,$possudom,$possuname))) {
+                            my $lowest_load = 30000;
+                            ($otherserver,$lowest_load) =
+                                &compare_server_load($try_server,undef,$lowest_load);
+                            if ($otherserver ne '' && $lowest_load < 100) {
+                                $has_session = 1;
+                            } else {
+                                undef($otherserver);
+                            }
+                        }
+                    }
+                }
+                if ($has_session) {
+                    if ($update_mtime) {
+                        my $atime = my $mtime = time;
+                        utime($atime,$mtime,"$balancedir/$cookie.id");
+                    }
+                } else {
+                    unlink("$balancedir/$cookie.id");
+                }
+            }
+        }
+    }
+    return ($otherserver,$cookie);
+}
+
+sub delbalcookie {
+    my ($cookie,$balancer) =@_;
+    if ($cookie =~ /^($match_domain)\_($match_username)\_[a-f0-9]{32}$/) {
+        my ($udom,$uname) = ($1,$2);
+        my $uprimary_id = &domain($udom,'primary');
+        my $uintdom = &internet_dom($uprimary_id);
+        my $intdom = &internet_dom($balancer);
+        my $serverhomedom = &host_domain($balancer);
+        if (($uintdom ne '') && ($uintdom eq $intdom)) {
+            return &reply("delbalcookie:$cookie",$balancer);
+        }
+    }
+}
+
 # -------------------------------- ask if server already has a session for user
 sub has_user_session {
     my ($lonid,$udom,$uname) = @_;
@@ -1061,7 +1166,7 @@ sub choose_server {
             if (ref($balancers) eq 'HASH') {
                 next if (exists($balancers->{$lonhost}));
             }
-        }   
+        }
         my $loginvia;
         if ($checkloginvia) {
             $loginvia = $domconfhash{$udom.'.login.loginvia_'.$lonhost};
@@ -1363,7 +1468,7 @@ sub get_lonbalancer_config {
 sub check_loadbalancing {
     my ($uname,$udom,$caller) = @_;
     my ($is_balancer,$currtargets,$currrules,$dom_in_use,$homeintdom,
-        $rule_in_effect,$offloadto,$otherserver);
+        $rule_in_effect,$offloadto,$otherserver,$setcookie,$dom_balancers);
     my $lonhost = $perlvar{'lonHostID'};
     my @hosts = &current_machine_ids();
     my $uprimary_id = &Apache::lonnet::domain($udom,'primary');
@@ -1390,7 +1495,7 @@ sub check_loadbalancing {
         }
     }
     if (ref($result) eq 'HASH') {
-        ($is_balancer,$currtargets,$currrules) = 
+        ($is_balancer,$currtargets,$currrules,$setcookie,$dom_balancers) =
             &check_balancer_result($result,@hosts);
         if ($is_balancer) {
             if (ref($currrules) eq 'HASH') {
@@ -1451,7 +1556,7 @@ sub check_loadbalancing {
             }
         }
         if (ref($result) eq 'HASH') {
-            ($is_balancer,$currtargets,$currrules) = 
+            ($is_balancer,$currtargets,$currrules,$setcookie,$dom_balancers) =
                 &check_balancer_result($result,@hosts);
             if ($is_balancer) {
                 if (ref($currrules) eq 'HASH') {
@@ -1517,20 +1622,22 @@ sub check_loadbalancing {
                 $is_balancer = 0;
                 if ($uname ne '' && $udom ne '') {
                     if (($env{'user.name'} eq $uname) && ($env{'user.domain'} eq $udom)) {
-                    
-                        &appenv({'user.loadbalexempt'     => $lonhost,  
+                        &appenv({'user.loadbalexempt'     => $lonhost,
                                  'user.loadbalcheck.time' => time});
                     }
                 }
             }
         }
+        unless ($homeintdom) {
+            undef($setcookie);
+        }
     }
-    return ($is_balancer,$otherserver);
+    return ($is_balancer,$otherserver,$setcookie,$offloadto,$dom_balancers);
 }
 
 sub check_balancer_result {
     my ($result,@hosts) = @_;
-    my ($is_balancer,$currtargets,$currrules);
+    my ($is_balancer,$currtargets,$currrules,$setcookie,$dom_balancers);
     if (ref($result) eq 'HASH') {
         if ($result->{'lonhost'} ne '') {
             my $currbalancer = $result->{'lonhost'};
@@ -1539,19 +1646,24 @@ sub check_balancer_result {
                 $currtargets = $result->{'targets'};
                 $currrules = $result->{'rules'};
             }
+            $dom_balancers = $currbalancer;
         } else {
-            foreach my $key (keys(%{$result})) {
-                if (($key ne '') && (grep(/^\Q$key\E$/,@hosts)) &&
-                    (ref($result->{$key}) eq 'HASH')) {
-                    $is_balancer = 1;
-                    $currrules = $result->{$key}{'rules'};
-                    $currtargets = $result->{$key}{'targets'};
-                    last;
+            if (keys(%{$result})) {
+                foreach my $key (keys(%{$result})) {
+                    if (($key ne '') && (grep(/^\Q$key\E$/,@hosts)) &&
+                        (ref($result->{$key}) eq 'HASH')) {
+                        $is_balancer = 1;
+                        $currrules = $result->{$key}{'rules'};
+                        $currtargets = $result->{$key}{'targets'};
+                        $setcookie = $result->{$key}{'cookie'};
+                        last;
+                    }
                 }
+                $dom_balancers = join(',',sort(keys(%{$result})));
             }
         }
     }
-    return ($is_balancer,$currtargets,$currrules);
+    return ($is_balancer,$currtargets,$currrules,$setcookie,$dom_balancers);
 }
 
 sub get_loadbalancer_targets {
@@ -3197,7 +3309,17 @@ sub ssi {
 
     $request->header(Cookie => $ENV{'HTTP_COOKIE'});
     my $lonhost = $perlvar{'lonHostID'};
-    my $response= &LONCAPA::LWPReq::makerequest($lonhost,$request,'',\%perlvar);
+    my $islocal;
+    if (($env{'request.course.id'}) &&
+        ($form{'grade_courseid'} eq $env{'request.course.id'}) &&
+        ($form{'grade_username'} ne '') && ($form{'grade_domain'} ne '') &&
+        ($form{'grade_symb'} ne '') &&
+        (&Apache::lonnet::allowed('mgr',$env{'request.course.id'}.
+                                 ($env{'request.course.sec'}?'/'.$env{'request.course.sec'}:'')))) {
+        $islocal = 1;
+    }
+    my $response= &LONCAPA::LWPReq::makerequest($lonhost,$request,'',\%perlvar,
+                                                '','','',$islocal);
 
     if (wantarray) {
 	return ($response->content, $response);
@@ -5231,7 +5353,12 @@ sub set_first_access {
     }
     $cachedkey='';
     my $firstaccess=&get_first_access($type,$symb,$map);
-    if (!$firstaccess) {
+    if ($firstaccess) {
+        &logthis("First access time already set ($firstaccess) when attempting ".
+                 "to set new value (type: $type, extent: $res) for $uname:$udom ".
+                 "in $courseid");
+        return 'already_set';
+    } else {
         my $start = time;
 	my $putres = &put('firstaccesstimes',{"$courseid\0$res"=>$start},
                           $udom,$uname);
@@ -5247,6 +5374,9 @@ sub set_first_access {
             if (($cachedtime) && (abs($start-$cachedtime) < 5)) {
                 $cachedtimes{"$courseid\0$res"} = $start;
             }
+        } elsif ($putres ne 'refused') {
+            &logthis("Result: $putres when attempting to set first access time ".
+                     "(type: $type, extent: $res) for $uname:$udom in $courseid");
         }
         return $putres;
     }
@@ -10041,12 +10171,25 @@ sub is_course {
     my ($cdom, $cnum) = scalar(@_) == 1 ? 
          ($_[0] =~ /^($match_domain)_($match_courseid)$/)  :  @_;
 
-    return unless $cdom and $cnum;
-
-    my %courses = &courseiddump($cdom, '.', 1, '.', '.', $cnum, undef, undef,
-        '.');
-
-    return unless(exists($courses{$cdom.'_'.$cnum}));
+    return unless (($cdom =~ /^$match_domain$/) && ($cnum =~ /^$match_courseid$/));
+    my $uhome=&homeserver($cnum,$cdom);
+    my $iscourse;
+    if (grep { $_ eq $uhome } current_machine_ids()) {
+        $iscourse = &LONCAPA::Lond::is_course($cdom,$cnum);
+    } else {
+        my $hashid = $cdom.':'.$cnum;
+        ($iscourse,my $cached) = &is_cached_new('iscourse',$hashid);
+        unless (defined($cached)) {
+            my %courses = &courseiddump($cdom, '.', 1, '.', '.',
+                                        $cnum,undef,undef,'.');
+            $iscourse = 0;
+            if (exists($courses{$cdom.'_'.$cnum})) {
+                $iscourse = 1;
+            }
+            &do_cache_new('iscourse',$hashid,$iscourse,3600);
+        }
+    }
+    return unless ($iscourse);
     return wantarray ? ($cdom, $cnum) : $cdom.'_'.$cnum;
 }