fix side effects from seekability test on input file

Fixes Bug #1007093

Mixing use of os.lseek(fileno, 0, os.SEEK_SET) with
file.seek seems to cause problems when reading data
with file.read

Change-Id: Ia96ce9bbdc93a1a8c6169d85b99187f8cd7b2fdc

glance/common/client.py

@@ -566,7 +566,7 @@ def _seekable(self, body):
         #   cat /path/to/image | glance add ...
         # or where add command is launched via popen
         try:
-            os.lseek(body.fileno(), 0, os.SEEK_SET)
+            os.lseek(body.fileno(), 0, os.SEEK_CUR)
             return True
         except OSError as e:
             return (e.errno != errno.ESPIPE)

glance/tests/unit/test_clients.py

@@ -1882,6 +1882,31 @@ def add_image_with_image_data_as_file(self, sendfile):
         for k, v in fixture.items():
             self.assertEquals(v, new_meta[k])
 
+    def test_added_image_notdoubled(self):
+        """Tests contents of an added small seekable image, when using ssl"""
+        fixture = {'name': 'fake public image',
+                   'disk_format': 'vhd',
+                   'container_format': 'ovf'
+                  }
+
+        tmp_fp = tempfile.TemporaryFile('w+')
+        image_data_fixture = _gen_uuid()
+        tmp_fp.write(image_data_fixture)
+        tmp_fp.seek(0)
+
+        self.client.use_ssl = True
+        new_image = self.client.add_image(fixture, tmp_fp)
+        new_image_id = new_image['id']
+
+        tmp_fp.close()
+
+        new_meta, new_image_chunks = self.client.get_image(new_image_id)
+        new_image_data = ""
+        for chunk in new_image_chunks:
+            new_image_data += chunk
+
+        self.assertEquals(image_data_fixture, new_image_data)
+
     @test_utils.skip_if(not base_client.SENDFILE_SUPPORTED,
                         'sendfile not supported')
     def test_add_image_with_image_data_as_file_with_sendfile(self):