httpd: check for null Subject in Transfer info

Motivation:

The httpd transfer collector classes periodically send
requests to the login broker.  Under certain conditions
it is possible for the reply to contain incomplete
information.  This is particularly true if the reply is sent
before login or file resolution has completed.

Since the TransferObserver and webadmin mapper classes attempt
to convert the Subject into a UserInfo object using the Subjects
methods, a NPE is generated if the Subject is null.

Modification:

Check for the null subject where UserInfo is set and
provide a UserInfo object with an empty constructor in
that case.

Result:

No NullPointerException.

Affects only master (changes introduced by 9258).

Target: master
Acked-by: Gerd

modules/dcache-vehicles/src/main/java/diskCacheV111/vehicles/IoDoorEntry.java

@@ -58,6 +58,13 @@ public String getStatus()
         return _status;
     }
 
+    /**
+     *  Under certain conditions it is possible to receive
+     *  transfer info sent before login has been performed
+     *  by the door.  It is thus possible that the Subject
+     *  also be <code>null</code>.
+     */
+    @Nullable
     public Subject getSubject()
     {
         return _subject;

modules/dcache-webadmin/src/main/java/org/dcache/webadmin/controller/util/BeanDataMapper.java

@@ -9,6 +9,7 @@
 import diskCacheV111.pools.PoolCostInfo.PoolQueueInfo;
 import diskCacheV111.services.space.LinkGroup;
 import diskCacheV111.services.space.Space;
+import diskCacheV111.util.UserInfo;
 import diskCacheV111.util.VOInfo;
 import diskCacheV111.vehicles.IoJobInfo;
 import diskCacheV111.vehicles.RestoreHandlerInfo;
@@ -126,7 +127,11 @@ public static ActiveTransfersBean moverModelToView(TransferCollector.Transfer tr
         ActiveTransfersBean bean = new ActiveTransfersBean();
         bean.setDomainName(transfer.door().getDomainName());
         bean.setCellName(transfer.door().getCellName());
-        bean.setSubject(transfer.session().getSubject());
+        if (transfer.session().getSubject() == null) {
+            bean.setUserInfo(new UserInfo());
+        } else {
+            bean.setSubject(transfer.session().getSubject());
+        }
         if (transfer.session().getPnfsId() == null) {
             bean.setPnfsId("");
         } else {

modules/dcache/src/main/java/diskCacheV111/cells/TransferObserverV1.java

@@ -19,9 +19,11 @@
 import java.util.Objects;
 import java.util.concurrent.ExecutionException;
 import java.util.stream.Collectors;
+import javax.security.auth.Subject;
 
 import diskCacheV111.util.HTMLBuilder;
 import diskCacheV111.util.TransferInfo;
+import diskCacheV111.util.UserInfo;
 import diskCacheV111.vehicles.IoDoorInfo;
 import diskCacheV111.vehicles.IoJobInfo;
 import dmg.cells.nucleus.CellAdapter;
@@ -167,7 +169,12 @@ public TransferBean(Transfer transfer, long now) {
             serialId = transfer.session().getSerialId();
             setProtocol(transfer.door().getProtocolFamily(),
                             transfer.door().getProtocolVersion());
-            setSubject(transfer.session().getSubject());
+            Subject subject = transfer.session().getSubject();
+            if (subject == null) {
+                setUserInfo(new UserInfo());
+            } else {
+                setSubject(subject);
+            }
             process = transfer.door().getProcess();
             pnfsId = Objects.toString(transfer.session().getPnfsId(), "");
             pool = Objects.toString(transfer.session().getPool(), "");

modules/dcache/src/main/java/diskCacheV111/util/UserInfo.java

@@ -62,9 +62,9 @@ LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import javax.security.auth.Subject;
 import java.io.Serializable;
 import java.util.NoSuchElementException;
+import javax.security.auth.Subject;
 
 import org.dcache.auth.FQAN;
 import org.dcache.auth.Subjects;