--- loncom/lonnet/perl/lonnet.pm	2017/12/29 23:51:50	1.1365
+++ loncom/lonnet/perl/lonnet.pm	2018/08/09 14:04:35	1.1381
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.1365 2017/12/29 23:51:50 raeburn Exp $
+# $Id: lonnet.pm,v 1.1381 2018/08/09 14:04:35 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -652,31 +652,39 @@ sub transfer_profile_to_env {
 sub check_for_valid_session {
     my ($r,$name,$userhashref,$domref) = @_;
     my %cookies=CGI::Cookie->parse($r->header_in('Cookie'));
-    my ($linkname,$pubname);
-    if ($name eq '') {
-        $name = 'lonID';
+    my ($lonidsdir,$linkname,$pubname,$secure,$lonid);
+    if ($name eq 'lonDAV') {
+        $lonidsdir=$r->dir_config('lonDAVsessDir');
+    } else {
+        $lonidsdir=$r->dir_config('lonIDsDir');
+        if ($name eq '') {
+            $name = 'lonID';
+        }
+    }
+    if ($name eq 'lonID') {
+        $secure = 'lonSID';
         $linkname = 'lonLinkID';
         $pubname = 'lonPubID';
-    }
-    my $lonid=$cookies{$name};
-    if (!$lonid) {
-        if (($name eq 'lonID') && ($ENV{'SERVER_PORT'} != 443) && ($linkname)) {
+        if (exists($cookies{$secure})) {
+            $lonid=$cookies{$secure};
+        } elsif (exists($cookies{$name})) {
+            $lonid=$cookies{$name};
+        } elsif (exists($cookies{$linkname})) {
             $lonid=$cookies{$linkname};
+        } elsif (exists($cookies{$pubname})) {
+            $lonid=$cookies{$pubname};
         }
-        if (!$lonid) {
-            if (($name eq 'lonID') && ($pubname)) {
-                $lonid=$cookies{$pubname};
-            }
-        }
+    } else {
+        $lonid=$cookies{$name};
     }
     return undef if (!$lonid);
 
     my $handle=&LONCAPA::clean_handle($lonid->value);
-    my $lonidsdir;
-    if ($name eq 'lonDAV') {
-        $lonidsdir=$r->dir_config('lonDAVsessDir');
-    } else {
-        $lonidsdir=$r->dir_config('lonIDsDir');
+    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/$handle.id") {
         if ((ref($domref)) && ($name eq 'lonID') && 
@@ -708,6 +716,10 @@ sub check_for_valid_session {
         $userhashref->{'name'} = $disk_env{'user.name'};
         $userhashref->{'domain'} = $disk_env{'user.domain'};
         $userhashref->{'lti'} = $disk_env{'request.lti.login'};
+        if ($userhashref->{'lti'}) {
+            $userhashref->{'ltitarget'} = $disk_env{'request.lti.target'};
+            $userhashref->{'ltiuri'} = $disk_env{'request.lti.uri'};
+        }
     }
 
     return $handle;
@@ -758,16 +770,19 @@ sub appenv {
                 $env{$key}=$newenv->{$key};
             }
         }
-        my $opened = open(my $env_file,'+<',$env{'user.environment'});
-        if ($opened
-	    && &timed_flock($env_file,LOCK_EX)
-	    &&
-	    tie(my %disk_env,'GDBM_File',$env{'user.environment'},
-	        (&GDBM_WRITER()|&GDBM_NOLOCK()),0640)) {
-	    while (my ($key,$value) = each(%{$newenv})) {
-	        $disk_env{$key} = $value;
-	    }
-	    untie(%disk_env);
+        my $lonids = $perlvar{'lonIDsDir'};
+        if ($env{'user.environment'} =~ m{^\Q$lonids/\E$match_username\_\d+\_$match_domain\_[\w\-.]+\.id$}) {
+            my $opened = open(my $env_file,'+<',$env{'user.environment'});
+            if ($opened
+	        && &timed_flock($env_file,LOCK_EX)
+	        &&
+	        tie(my %disk_env,'GDBM_File',$env{'user.environment'},
+	            (&GDBM_WRITER()|&GDBM_NOLOCK()),0640)) {
+	        while (my ($key,$value) = each(%{$newenv})) {
+	            $disk_env{$key} = $value;
+	        }
+	        untie(%disk_env);
+            }
         }
     }
     return 'ok';
@@ -7146,6 +7161,7 @@ sub usertools_access {
                       community  => 1,
                       textbook   => 1,
                       placement  => 1,
+                      lti        => 1,
                  );
     } elsif ($context eq 'requestauthor') {
         %tools = (
@@ -7342,25 +7358,29 @@ sub is_advanced_user {
 }
 
 sub check_can_request {
-    my ($dom,$can_request,$request_domains) = @_;
+    my ($dom,$can_request,$request_domains,$uname,$udom) = @_;
     my $canreq = 0;
+    if (($env{'user.name'} ne '') && ($env{'user.domain'} ne '')) {
+        $uname = $env{'user.name'};
+        $udom = $env{'user.domain'};
+    }
     my ($types,$typename) = &Apache::loncommon::course_types();
     my @options = ('approval','validate','autolimit');
     my $optregex = join('|',@options);
     if ((ref($can_request) eq 'HASH') && (ref($types) eq 'ARRAY')) {
         foreach my $type (@{$types}) {
-            if (&usertools_access($env{'user.name'},
-                                  $env{'user.domain'},
-                                  $type,undef,'requestcourses')) {
+            if (&usertools_access($uname,$udom,$type,undef,
+                                  'requestcourses')) {
                 $canreq ++;
                 if (ref($request_domains) eq 'HASH') {
-                    push(@{$request_domains->{$type}},$env{'user.domain'});
+                    push(@{$request_domains->{$type}},$udom);
                 }
-                if ($dom eq $env{'user.domain'}) {
+                if ($dom eq $udom) {
                     $can_request->{$type} = 1;
                 }
             }
-            if ($env{'environment.reqcrsotherdom.'.$type} ne '') {
+            if (($env{'user.name'} ne '') && ($env{'user.domain'} ne '') &&
+                ($env{'environment.reqcrsotherdom.'.$type} ne '')) {
                 my @curr = split(',',$env{'environment.reqcrsotherdom.'.$type});
                 if (@curr > 0) {
                     foreach my $item (@curr) {
@@ -7377,7 +7397,7 @@ sub check_can_request {
                             }
                         }
                     }
-                    unless($dom eq $env{'user.domain'}) {
+                    unless ($dom eq $env{'user.domain'}) {
                         $canreq ++;
                         if (grep(/^\Q$dom\E:($optregex)(=?\d*)$/,@curr)) {
                             $can_request->{$type} = 1;
@@ -8892,6 +8912,33 @@ sub auto_validate_class_sec {
     return $response;
 }
 
+sub auto_validate_instclasses {
+    my ($cdom,$cnum,$owners,$classesref) = @_;
+    my ($homeserver,%validations);
+    $homeserver = &homeserver($cnum,$cdom);
+    unless ($homeserver eq 'no_host') {
+        my $ownerlist;
+        if (ref($owners) eq 'ARRAY') {
+            $ownerlist = join(',',@{$owners});
+        } else {
+            $ownerlist = $owners;
+        }
+        if (ref($classesref) eq 'HASH') {
+            my $classes = &freeze_escape($classesref);
+            my $response=&reply('autovalidateinstclasses:'.&escape($ownerlist).
+                                ':'.$cdom.':'.$classes,$homeserver);
+            unless ($response =~ /(con_lost|error|no_such_host|refused)/) {
+                my @items = split(/&/,$response);
+                foreach my $item (@items) {
+                    my ($key,$value) = split('=',$item);
+                    $validations{&unescape($key)} = &thaw_unescape($value);
+                }
+            }
+        }
+    }
+    return %validations;
+}
+
 sub auto_crsreq_update {
     my ($cdom,$cnum,$crstype,$action,$ownername,$ownerdomain,$fullname,$title,
         $code,$accessstart,$accessend,$inbound) = @_;
@@ -9251,7 +9298,7 @@ sub assignrole {
             }
             if ($refused) {
                 my ($cdom,$cnum) = ($cwosec =~ m{^/?($match_domain)/($match_courseid)$});
-                if (!$selfenroll && $context eq 'course') {
+                if (!$selfenroll && (($context eq 'course') || ($context eq 'ltienroll' && $env{'request.lti.login'}))) {
                     my %crsenv;
                     if ($role eq 'cc' || $role eq 'co') {
                         %crsenv = &userenvironment($cdom,$cnum,('internal.courseowner'));
@@ -9271,8 +9318,12 @@ sub assignrole {
                             }
                         }
                     }
-                } elsif (($selfenroll == 1) && ($role eq 'st') && ($udom eq $env{'user.domain'}) && ($uname eq $env{'user.name'})) {
-                    $refused = '';
+                } elsif (($selfenroll == 1) && ($udom eq $env{'user.domain'}) && ($uname eq $env{'user.name'})) {
+                    if ($role eq 'st') {
+                        $refused = '';
+                    } elsif (($context eq 'ltienroll') && ($env{'request.lti.login'})) {
+                        $refused = '';
+                    }
                 } elsif ($context eq 'requestcourses') {
                     my @possroles = ('st','ta','ep','in','cc','co');
                     if ((grep(/^\Q$role\E$/,@possroles)) && ($env{'user.name'} ne '' && $env{'user.domain'} ne '')) {
@@ -9538,10 +9589,14 @@ sub modifyuser {
     my $newuser;
     if ($uhome eq 'no_host') {
         $newuser = 1;
+        unless (($umode && ($upass ne '')) || ($umode eq 'localauth') ||
+                ($umode eq 'lti')) {
+            return 'error: more information needed to create new user';
+        }
     }
 # ----------------------------------------------------------------- Create User
     if (($uhome eq 'no_host') && 
-	(($umode && $upass) || ($umode eq 'localauth'))) {
+	(($umode && $upass) || ($umode eq 'localauth') || ($umode eq 'lti'))) {
         my $unhome='';
         if (defined($desiredhome) && &host_domain($desiredhome) eq $udom) { 
             $unhome = $desiredhome;
@@ -9986,12 +10041,25 @@ sub is_course {
     my ($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()) {
+        $iscourse = &Lond::is_course($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;
 }
 
@@ -11204,10 +11272,11 @@ sub get_numsuppfiles {
     unless (defined($cached)) {
         my $chome=&homeserver($cnum,$cdom);
         unless ($chome eq 'no_host') {
-            ($suppcount,my $errors) = (0,0);
+            ($suppcount,my $supptools,my $errors) = (0,0,0);
             my $suppmap = 'supplemental.sequence';
-            ($suppcount,$errors) = 
-                &Apache::loncommon::recurse_supplemental($cnum,$cdom,$suppmap,$suppcount,$errors);
+            ($suppcount,$supptools,$errors) =
+                &Apache::loncommon::recurse_supplemental($cnum,$cdom,$suppmap,$suppcount,
+                                                         $supptools,$errors);
         }
         &do_cache_new('suppcount',$hashid,$suppcount,600);
     }
@@ -11694,6 +11763,7 @@ sub add_prefix_and_part {
 
 my %metaentry;
 my %importedpartids;
+my %importedrespids;
 sub metadata {
     my ($uri,$what,$toolsymb,$liburi,$prefix,$depthcount)=@_;
     $uri=&declutter($uri);
@@ -11780,9 +11850,11 @@ sub metadata {
 
     {
 # Imported parts would go here
-        my %importedids=();
-        my @origfileimportpartids=();
+        my @origfiletagids=();
         my $importedparts=0;
+
+# Imported responseids would go here
+        my $importedresponses=0;
 #
 # Is this a recursive call for a library?
 #
@@ -11877,27 +11949,77 @@ sub metadata {
                         my $dir=$filename;
                         $dir=~s|[^/]*$||;
                         $location=&filelocation($dir,$location);
-                       
+
+                        my $importid=$token->[2]->{'id'};
                         my $importmode=$token->[2]->{'importmode'};
-                        if ($importmode eq 'problem') {
-# Import as problem/response
-                           $unikey=&add_prefix_and_part($prefix,$token->[2]->{'part'});
-                        } elsif ($importmode eq 'part') {
+#
+# Check metadata for imported file to
+# see if it contained response items
+#
+                        my ($origfile,@libfilekeys);
+                        my %currmetaentry = %metaentry;
+                        @libfilekeys = split(/,/,&metadata($location,'keys',undef,undef,undef,
+                                                           $depthcount+1));
+                        if (grep(/^responseorder$/,@libfilekeys)) {
+                            my $libresponseorder = &metadata($location,'responseorder',undef,undef,
+                                                             undef,$depthcount+1);
+                            if ($libresponseorder ne '') {
+                                if ($#origfiletagids<0) {
+                                    undef(%importedrespids);
+                                    undef(%importedpartids);
+                                }
+                                my @respids = split(/\s*,\s*/,$libresponseorder);
+                                if (@respids) {
+                                    $importedrespids{$importid} = join(',',map { $importid.'_'.$_ } @respids);
+                                }
+                                if ($importedrespids{$importid} ne '') {
+                                    $importedresponses = 1;
+# We need to get the original file and the imported file to get the response order correct
+# Load and inspect original file
+                                    if ($#origfiletagids<0) {
+                                        my $origfilelocation=$perlvar{'lonDocRoot'}.&clutter($uri);
+                                        $origfile=&getfile($origfilelocation);
+                                        @origfiletagids=($origfile=~/<((?:\w+)response|import|part)[^>]*id\s*=\s*[\"\']([^\"\']+)[\"\'][^>]*>/gs);
+                                    }
+                                }
+                            }
+                        }
+# Do not overwrite contents of %metaentry hash for resource itself with 
+# hash populated for imported library file
+                        %metaentry = %currmetaentry;
+                        undef(%currmetaentry);
+                        if ($importmode eq 'part') {
 # Import as part(s)
                            $importedparts=1;
 # We need to get the original file and the imported file to get the part order correct
 # Good news: we do not need to worry about nested libraries, since parts cannot be nested
-# Load and inspect original file
-                           if ($#origfileimportpartids<0) {
-                              undef(%importedpartids);
-                              my $origfilelocation=$perlvar{'lonDocRoot'}.&clutter($uri);
-                              my $origfile=&getfile($origfilelocation);
-                              @origfileimportpartids=($origfile=~/<(part|import)[^>]*id\s*=\s*[\"\']([^\"\']+)[\"\'][^>]*>/gs);
+# Load and inspect original file if we didn't do that already
+                           if ($#origfiletagids<0) {
+                               undef(%importedrespids);
+                               undef(%importedpartids);
+                               if ($origfile eq '') {
+                                   my $origfilelocation=$perlvar{'lonDocRoot'}.&clutter($uri);
+                                   $origfile=&getfile($origfilelocation);
+                                   @origfiletagids=($origfile=~/<(part|import)[^>]*id\s*=\s*[\"\']([^\"\']+)[\"\'][^>]*>/gs);
+                               }
+                           }
+                           my @impfilepartids;
+# If <partorder> tag is included in metadata for the imported file
+# get the parts in the imported file from that.
+                           if (grep(/^partorder$/,@libfilekeys)) {
+                               %currmetaentry = %metaentry;
+                               my $libpartorder = &metadata($location,'partorder',undef,undef,undef,
+                                                            $depthcount+1);
+                               %metaentry = %currmetaentry;
+                               undef(%currmetaentry);
+                               if ($libpartorder ne '') {
+                                   @impfilepartids=split(/\s*,\s*/,$libpartorder);
+                               }
+                           } else {
+# If no <partorder> tag available, load and inspect imported file
+                               my $impfile=&getfile($location);
+                               @impfilepartids=($impfile=~/<part[^>]*id\s*=\s*[\"\']([^\"\']+)[\"\'][^>]*>/gs);
                            }
-
-# Load and inspect imported file
-                           my $impfile=&getfile($location);
-                           my @impfilepartids=($impfile=~/<part[^>]*id\s*=\s*[\"\']([^\"\']+)[\"\'][^>]*>/gs);
                            if ($#impfilepartids>=0) {
 # This problem had parts
                                $importedpartids{$token->[2]->{'id'}}=join(',',@impfilepartids);
@@ -11908,13 +12030,28 @@ sub metadata {
                                $importedpartids{$token->[2]->{'id'}}=$token->[2]->{'id'};
                            }
                         } else {
+# Import as problem or as normal import
+                            $unikey=&add_prefix_and_part($prefix,$token->[2]->{'part'});
+                            unless ($importmode eq 'problem') {
 # Normal import
-                           $unikey=&add_prefix_and_part($prefix,$token->[2]->{'part'});
-                           if (defined($token->[2]->{'id'})) {
-                              $unikey.='_'.$token->[2]->{'id'};
-                           }
+                                if (defined($token->[2]->{'id'})) {
+                                    $unikey.='_'.$token->[2]->{'id'};
+                                }
+                            }
+# Check metadata for imported file to
+# see if it contained parts
+                            if (grep(/^partorder$/,@libfilekeys)) {
+                                %currmetaentry = %metaentry;
+                                my $libpartorder = &metadata($location,'partorder',undef,undef,undef,
+                                                             $depthcount+1);
+                                %metaentry = %currmetaentry;
+                                undef(%currmetaentry);
+                                if ($libpartorder ne '') {
+                                    $importedparts = 1;
+                                    $importedpartids{$token->[2]->{'id'}}=$libpartorder;
+                                }
+                            }
                         }
-
 			if ($depthcount<20) {
 			    my $metadata = 
 				&metadata($uri,'keys',$toolsymb,$location,$unikey,
@@ -11923,7 +12060,6 @@ sub metadata {
 				$metaentry{':'.$meta}=$metaentry{':'.$meta};
 				$metathesekeys{$meta}=1;
 			    }
-			
                         }
 		    } else {
 #
@@ -12006,26 +12142,57 @@ sub metadata {
 	    grep { ! $seen{$_} ++ } (split(',',$metaentry{':packages'}));
 	$metaentry{':packages'} = join(',',@uniq_packages);
 
-        if ($importedparts) {
+        if (($importedresponses) || ($importedparts)) {
+            if ($importedparts) {
 # We had imported parts and need to rebuild partorder
-           $metaentry{':partorder'}='';
-           $metathesekeys{'partorder'}=1;
-           for (my $index=0;$index<$#origfileimportpartids;$index+=2) {
-               if ($origfileimportpartids[$index] eq 'part') {
-# original part, part of the problem
-                  $metaentry{':partorder'}.=','.$origfileimportpartids[$index+1];
-               } else {
-# we have imported parts at this position
-                  $metaentry{':partorder'}.=','.$importedpartids{$origfileimportpartids[$index+1]};
-               }
-           }
-           $metaentry{':partorder'}=~s/^\,//;
+                $metaentry{':partorder'}='';
+                $metathesekeys{'partorder'}=1;
+            }
+            if ($importedresponses) {
+# We had imported responses and need to rebuil responseorder
+                $metaentry{':responseorder'}='';
+                $metathesekeys{'responseorder'}=1;
+            }
+            for (my $index=0;$index<$#origfiletagids;$index+=2) {
+                my $origid = $origfiletagids[$index+1];
+                if ($origfiletagids[$index] eq 'part') {
+# Original part, part of the problem
+                    if ($importedparts) {
+                        $metaentry{':partorder'}.=','.$origid;
+                    }
+                } elsif ($origfiletagids[$index] eq 'import') {
+                    if ($importedparts) {
+# We have imported parts at this position
+                        if ($importedpartids{$origid} ne '') {
+                            $metaentry{':partorder'}.=','.$importedpartids{$origid};
+                        }
+                    }
+                    if ($importedresponses) {
+# We have imported responses at this position
+                        if ($importedrespids{$origid} ne '') {
+                            $metaentry{':responseorder'}.=','.$importedrespids{$origid};
+                        }
+                    }
+                } else {
+# Original response item, part of the problem
+                    if ($importedresponses) {
+                        $metaentry{':responseorder'}.=','.$origid;
+                    }
+                }
+            }
+            if ($importedparts) {
+                $metaentry{':partorder'}=~s/^\,//;
+            }
+            if ($importedresponses) {
+                $metaentry{':responseorder'}=~s/^\,//;
+            }
         }
-
 	$metaentry{':keys'} = join(',',keys(%metathesekeys));
 	&metadata_generate_part0(\%metathesekeys,\%metaentry,$uri);
 	$metaentry{':allpossiblekeys'}=join(',',keys(%metathesekeys));
-	&do_cache_new('meta',$uri,\%metaentry,$cachetime);
+        unless ($liburi) {
+	    &do_cache_new('meta',$uri,\%metaentry,$cachetime);
+        }
 # this is the end of "was not already recently cached
     }
     return $metaentry{':'.$what};
@@ -13365,15 +13532,17 @@ sub get_dns {
     }
 
     my %alldns;
-    open(my $config,"<","$perlvar{'lonTabDir'}/hosts.tab");
-    foreach my $dns (<$config>) {
-	next if ($dns !~ /^\^(\S*)/x);
-        my $line = $1;
-        my ($host,$protocol) = split(/:/,$line);
-        if ($protocol ne 'https') {
-            $protocol = 'http';
+    if (open(my $config,"<","$perlvar{'lonTabDir'}/hosts.tab")) {
+        foreach my $dns (<$config>) {
+	    next if ($dns !~ /^\^(\S*)/x);
+            my $line = $1;
+            my ($host,$protocol) = split(/:/,$line);
+            if ($protocol ne 'https') {
+                $protocol = 'http';
+            }
+	    $alldns{$host} = $protocol;
         }
-	$alldns{$host} = $protocol;
+        close($config);
     }
     while (%alldns) {
 	my ($dns) = sort { $b cmp $a } keys(%alldns);
@@ -13381,19 +13550,33 @@ sub get_dns {
         my $response = &LONCAPA::LWPReq::makerequest('',$request,'',\%perlvar,30,0);
         delete($alldns{$dns});
 	next if ($response->is_error());
-	my @content = split("\n",$response->content);
-	unless ($nocache) {
-	    &do_cache_new('dns',$url,\@content,30*24*60*60);
-	}
-	&$func(\@content,$hashref);
-	return;
+        if ($url eq '/adm/dns/loncapaCRL') {
+            return &$func($response);
+        } else {
+	    my @content = split("\n",$response->content);
+	    unless ($nocache) {
+	        &do_cache_new('dns',$url,\@content,30*24*60*60);
+	    }
+	    &$func(\@content,$hashref);
+            return;
+        }
+    }
+    my $which = (split('/',$url,4))[3];
+    if ($which eq 'loncapaCRL') {
+        my $diskfile = "$perlvar{'lonCertificateDirectory'}/$perlvar{'lonnetCertRevocationList'}";
+        if (-e $diskfile) {
+            &logthis("unable to contact DNS, on disk file $diskfile not updated");
+        } else {
+            &logthis("unable to contact DNS, no on disk file $diskfile available");
+        }
+    } else {
+        &logthis("unable to contact DNS defaulting to on disk file dns_$which.tab\n");
+        if (open(my $config,"<","$perlvar{'lonTabDir'}/dns_$which.tab")) {
+            my @content = <$config>;
+            close($config);
+            &$func(\@content,$hashref);
+        }
     }
-    close($config);
-    my $which = (split('/',$url))[3];
-    &logthis("unable to contact DNS defaulting to on disk file dns_$which.tab\n");
-    open($config,"<","$perlvar{'lonTabDir'}/dns_$which.tab");
-    my @content = <$config>;
-    &$func(\@content,$hashref);
     return;
 }
 
@@ -13453,6 +13636,79 @@ sub fetch_dns_checksums {
     return \%checksums;
 }
 
+sub fetch_crl_pemfile {
+    return &get_dns("/adm/dns/loncapaCRL",\&save_crl_pem,1,1);
+}
+
+sub save_crl_pem {
+    my ($response) = @_;
+    my ($msg,$hadchanges);
+    if (ref($response)) {
+        my $now = time;
+        my $lonca = $perlvar{'lonCertificateDirectory'}.'/'.$perlvar{'lonnetCertificateAuthority'};
+        my $tmpcrl = $tmpdir.'/'.$perlvar{'lonnetCertRevocationList'}.'_'.$now.'.'.$$.'.tmp';
+        if (open(my $fh,'>',"$tmpcrl")) {
+            print $fh $response->content;
+            close($fh);
+            if (-e $lonca) {
+                if (open(PIPE,"openssl crl -in $tmpcrl -inform pem -CAfile $lonca -noout 2>&1 |")) {
+                    my $check = <PIPE>;
+                    close(PIPE);
+                    chomp($check);
+                    if ($check eq 'verify OK') {
+                        my $dest = "$perlvar{'lonCertificateDirectory'}/$perlvar{'lonnetCertRevocationList'}";
+                        my $backup;
+                        if (-e $dest) {
+                            if (&File::Copy::move($dest,"$dest.bak")) {
+                                $backup = 'ok';
+                            }
+                        }
+                        if (&File::Copy::move($tmpcrl,$dest)) {
+                            $msg = 'ok';
+                            if ($backup) {
+                                my (%oldnums,%newnums);
+                                if (open(PIPE, "openssl crl -inform PEM -text -noout -in $dest.bak |grep 'Serial Number' |")) {
+                                    while (<PIPE>) {
+                                        $oldnums{(split(/:/))[1]} = 1;
+                                    }
+                                    close(PIPE);
+                                }
+                                if (open(PIPE, "openssl crl -inform PEM -text -noout -in $dest |grep 'Serial Number' |")) {
+                                    while(<PIPE>) {
+                                        $newnums{(split(/:/))[1]} = 1;
+                                    }
+                                    close(PIPE);
+                                }
+                                foreach my $key (sort {$b <=> $a } (keys(%newnums))) {
+                                    unless (exists($oldnums{$key})) {
+                                        $hadchanges = 1;
+                                        last;
+                                    }
+                                }
+                                unless ($hadchanges) {
+                                    foreach my $key (sort {$b <=> $a } (keys(%oldnums))) {
+                                        unless (exists($newnums{$key})) {
+                                            $hadchanges = 1;
+                                            last;
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    } else {
+                        unlink($tmpcrl);
+                    }
+                } else {
+                    unlink($tmpcrl);
+                }
+            } else {
+                unlink($tmpcrl);
+            }
+        }
+    }
+    return ($msg,$hadchanges);
+}
+
 # ------------------------------------------------------------ Read domain file
 {
     my $loaded;
@@ -14748,7 +15004,9 @@ only used internally for recursive metad
 the toolsymb is only used where the uri is for an external tool (for which
 the uri as well as the symb are guaranteed to be unique).
 
-this function automatically caches all requests
+this function automatically caches all requests except any made recursively
+to retrieve a list of metadata keys for an imported library file ($liburi is 
+defined).
 
 =item *