--- loncom/lonnet/perl/lonnet.pm	2018/07/04 16:58:29	1.1378
+++ loncom/lonnet/perl/lonnet.pm	2018/07/18 13:45:03	1.1379
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.1378 2018/07/04 16:58:29 raeburn Exp $
+# $Id: lonnet.pm,v 1.1379 2018/07/18 13:45:03 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -13519,15 +13519,17 @@ 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);
@@ -13535,19 +13537,33 @@ 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;
 }
 
@@ -13607,6 +13623,47 @@ 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 $msg;
+    if (ref($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'}";
+                        if (-e $dest) {
+                            &File::Copy::move($dest,"$dest.bak");
+                        }
+                        if (&File::Copy::move($tmpcrl,$dest)) {
+                            $msg = 'ok';
+                        }
+                    } else {
+                        unlink($tmpcrl);
+                    }
+                } else {
+                    unlink($tmpcrl);
+                }
+            } else {
+                unlink($tmpcrl);
+            }
+        }
+    }
+    return $msg;
+}
+
 # ------------------------------------------------------------ Read domain file
 {
     my $loaded;