SF #857297 and 916874, improve handling of hard links when extracting

Lib/tarfile.py

@@ -1294,6 +1294,10 @@ class TarFile(object):
         else:
             tarinfo = self.getmember(member)
 
+        # Prepare the link target for makelink().
+        if tarinfo.islnk():
+            tarinfo._link_target = os.path.join(path, tarinfo.linkname)
+
         try:
             self._extract_member(tarinfo, os.path.join(path, tarinfo.name))
         except EnvironmentError, e:
@@ -1466,7 +1470,8 @@ class TarFile(object):
             if tarinfo.issym():
                 os.symlink(linkpath, targetpath)
             else:
-                os.link(linkpath, targetpath)
+                # See extract().
+                os.link(tarinfo._link_target, targetpath)
         except AttributeError:
             if tarinfo.issym():
                 linkpath = os.path.join(os.path.dirname(tarinfo.name),

Lib/test/test_tarfile.py

@@ -293,6 +293,24 @@ class WriteGNULongTest(unittest.TestCase):
         self._test(("longnam/" * 127) + "longname_",
                    ("longlnk/" * 127) + "longlink_")
 
+class ExtractHardlinkTest(BaseTest):
+
+    def test_hardlink(self):
+        """Test hardlink extraction (bug #857297)
+        """
+        # Prevent errors from being caught
+        self.tar.errorlevel = 1
+
+        self.tar.extract("0-REGTYPE", dirname())
+        try:
+            # Extract 1-LNKTYPE which is a hardlink to 0-REGTYPE
+            self.tar.extract("1-LNKTYPE", dirname())
+        except EnvironmentError, e:
+            import errno
+            if e.errno == errno.ENOENT:
+                self.fail("hardlink not extracted properly")
+
+
 # Gzip TestCases
 class ReadTestGzip(ReadTest):
     comp = "gz"
@@ -337,6 +355,9 @@ def test_main():
         WriteGNULongTest,
     ]
 
+    if hasattr(os, "link"):
+        tests.append(ExtractHardlinkTest)
+
     if gzip:
         tests.extend([
             ReadTestGzip, ReadStreamTestGzip,

Misc/NEWS

@@ -39,6 +39,9 @@ Extension modules
 Library
 -------
 
+- Bug #857297/Patch #916874.  Fix an error when extracting a hard link
+  from a tarfile.
+
 - Patch #846659.  Fix an error in tarfile.py when using
   GNU longname/longlink creation.