HADOOP-18136. Verify FileUtils.unTar() handling of missing .tar files.

remove surplus params from tarhardened and update readme

Author: steveloughran

README.md

@@ -729,6 +729,36 @@ information to disable it if so.
 
 See [safeprefetch](src/main/site/safeprefetch.md)
 
+## Command `tarhardened`
+
+Verify the hadoop release has had its untar command hardened and will
+not evaluate commands passed in as filenames.
+
+```bash
+bin/hadoop jar $CLOUDSTORE tarhardened "file.tar; true"
+```
+
+*Bad*
+
+```
+Attempting to untar file with name "file.tar; true"
+untar operation reported success
+
+2023-01-27 16:42:35,931 [main] INFO  util.ExitUtil (ExitUtil.java:terminate(124)) - Exiting with status 0
+```
+
+Although the file doesn't exist, the bash "true" command was executed after the untar, so
+the operation was reported as a success.
+
+*Good*
+
+```
+2023-01-27 16:48:44,461 [main] INFO  util.ExitUtil (ExitUtil.java:terminate(210)) - Exiting with status -1: ExitCodeException exitCode=1: tar: Error opening archive: Failed to open 'file.tar; true'
+
+```
+
+The file `file.tar; true` was attempted to be opened; as it is not present the operation failed.
+Expect a stack trace in the report
 ## Command `tlsinfo`
 
 Print out tls information. The `storediag` command prints the same information;

src/main/java/org/apache/hadoop/fs/store/commands/TarHardened.java

@@ -28,9 +28,6 @@
 import org.apache.hadoop.fs.store.diag.DiagnosticsEntryPoint;
 import org.apache.hadoop.util.ToolRunner;
 
-import static org.apache.hadoop.fs.store.CommonParameters.DEFINE;
-import static org.apache.hadoop.fs.store.CommonParameters.VERBOSE;
-import static org.apache.hadoop.fs.store.CommonParameters.XMLFILE;
 import static org.apache.hadoop.fs.store.StoreExitCodes.E_USAGE;
 
 /**
@@ -42,14 +39,10 @@ public class TarHardened extends DiagnosticsEntryPoint {
   private static final Logger LOG = LoggerFactory.getLogger(TarHardened.class);
 
   public static final String USAGE
-      = "Usage: tarhardened [filename]\n"
-      + optusage(DEFINE, "key=value", "Define a property")
-      + optusage(XMLFILE, "file", "XML config file to load")
-      + optusage(VERBOSE, "verbose output");
+      = "Usage: tarhardened [filename]";
 
   public TarHardened() {
-    createCommandFormat(1, 1, VERBOSE);
-    addValueOptions(XMLFILE, DEFINE);
+    createCommandFormat(0, 1);
   }
 
   @Override