--- loncom/lond	2019/07/18 18:28:40	1.560
+++ loncom/lond	2020/03/30 11:04:03	1.561
@@ -2,7 +2,7 @@
 # The LearningOnline Network
 # lond "LON Daemon" Server (port "LOND" 5663)
 #
-# $Id: lond,v 1.560 2019/07/18 18:28:40 raeburn Exp $
+# $Id: lond,v 1.561 2020/03/30 11:04:03 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -65,7 +65,7 @@ my $DEBUG = 0;		       # Non zero to ena
 my $status='';
 my $lastlog='';
 
-my $VERSION='$Revision: 1.560 $'; #' stupid emacs
+my $VERSION='$Revision: 1.561 $'; #' stupid emacs
 my $remoteVERSION;
 my $currenthostid="default";
 my $currentdomainid;
@@ -220,6 +220,7 @@ my %trust = (
                courseidput => {remote => 1, domroles => 1, enroll => 1},
                courseidputhash => {remote => 1, domroles => 1, enroll => 1},
                courselastaccess => {remote => 1, domroles => 1, enroll => 1},
+               coursesessions => {institutiononly => 1},
                currentauth => {remote => 1, domroles => 1, enroll => 1},
                currentdump => {remote => 1, enroll => 1},
                currentversion => {remote=> 1, content => 1},
@@ -2443,7 +2444,7 @@ sub change_password_handler {
 	    my $result = &change_unix_password($uname, $npass);
             if ($result eq 'ok') {
                 &update_passwd_history($uname,$udom,$howpwd,$context);
-             }
+            }
 	    &logthis("Result of password change for $uname: ".
 		     $result);
 	    &Reply($client, \$result, $userinput);
@@ -4873,6 +4874,45 @@ sub course_lastaccess_handler {
 }
 &register_handler("courselastaccess",\&course_lastaccess_handler, 0, 1, 0);
 
+sub course_sessions_handler {
+    my ($cmd, $tail, $client) = @_;
+    my $userinput = "$cmd:$tail";
+    my ($cdom,$cnum,$lastactivity) = split(':',$tail);
+    my $dbsuffix = '_'.$cdom.'_'.$cnum.'.db';
+    my (%sessions,$qresult);
+    my $now=time;
+    if (opendir(DIR,$perlvar{'lonIDsDir'})) {
+        my $filename;
+        while ($filename=readdir(DIR)) {
+            next if ($filename=~/^\./);
+            next if ($filename=~/^publicuser_/);
+            next if ($filename=~/^[a-f0-9]+_(linked|lti_\d+)\.id$/);
+            if ($filename =~ /^($LONCAPA::match_user)_\d+_($LONCAPA::match_domain)_/) {
+                my ($uname,$udom) = ($1,$2);
+                next unless (-e "$perlvar{'lonDaemons'}/$uname$dbsuffix");
+                my $mtime = (stat("$perlvar{'lonIDsDir'}/$filename"))[9];
+                my $since=$now-$mtime;
+                if ($lastactivity < 0) {
+                    next if ($since <= $lastactivity);
+                } else {
+                    next if ($since > $lastactivity);
+                }
+                $sessions{$uname.':'.$udom} = $mtime;
+            }
+        }
+        closedir(DIR); 
+    }
+    foreach my $user (keys(%sessions)) {
+        $qresult.=&escape($user).'='.$sessions{$user}.'&';
+    }
+    if ($qresult) {
+        chop($qresult);
+    }
+    &Reply($client, \$qresult, $userinput);
+    return 1;
+}
+&register_handler("coursesessions",\&course_sessions_handler, 0, 1, 0);
+
 #
 # Puts an unencrypted entry in a namespace db file at the domain level 
 #