Fix extraction of long file names in Tar

PR:	15230
Submitted by:	J. David Beutel


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@275040 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/tar/TarInputStream.java

@@ -275,6 +275,12 @@ public class TarInputStream extends FilterInputStream {
                 longName.append(new String(buffer, 0, length));
             }
             getNextEntry();
+
+            // remove trailing null terminator
+            if (longName.length() > 0
+                && longName.charAt(longName.length() - 1) == 0) {
+                longName.deleteCharAt(longName.length() - 1);
+            }
             this.currEntry.setName(longName.toString());
         }
 

src/testcases/org/apache/tools/tar/TarRoundTripTest.java

@@ -0,0 +1,42 @@
+package org.apache.tools.tar;
+
+import java.io.IOException;
+import java.io.ByteArrayOutputStream;
+import junit.framework.TestCase;
+
+public class TarRoundTripTest extends TestCase {
+
+    private static final String LONG_NAME
+        = "this/path/name/contains/more/than/one/hundred/characters/in/order/"
+            + "to/test/the/GNU/long/file/name/capability/round/tripped";
+
+    public TarRoundTripTest(String name) {
+        super(name);
+    }
+
+    /**
+     * test round-tripping long (GNU) entries
+     */
+    public void testLongRoundTripping() throws IOException {
+        TarEntry original = new TarEntry(LONG_NAME);
+        assertEquals("over 100 chars", true, LONG_NAME.length() > 100);
+        assertEquals("original name", LONG_NAME, original.getName());
+
+
+        ByteArrayOutputStream buff = new ByteArrayOutputStream();
+        TarOutputStream tos = new TarOutputStream(buff);
+        tos.setLongFileMode(TarOutputStream.LONGFILE_GNU);
+        tos.putNextEntry(original);
+        tos.closeEntry();
+        tos.close();
+
+        TarInputStream tis
+            = new TarInputStream(new ByteArrayInputStream(buff.toByteArray()));
+        TarEntry tripped = tis.getNextEntry();
+        assertEquals("round-tripped name", LONG_NAME, tripped.getName());
+        assertNull("no more entries", tis.getNextEntry());
+        tis.close();
+    }
+}
+
+