Introduce SAFT TPM testing support.

kernel_handler.py

 #!/usr/bin/python
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 '''A module containing kernel handler class used by SAFT.'''
 
 import re
 
 TMP_FILE_NAME = 'kernel_header_dump'
 MAIN_STORAGE_DEVICE = '/dev/sda'
 
     # Types of kernel modifications.
 KERNEL_BODY_MOD = 1
 KERNEL_VERSION_MOD = 2
 
+
+class KernelHandlerError(Exception):
+    pass
+
+
 class KernelHandler(object):
     '''An object to provide ChromeOS kernel related actions.
 
     Mostly it allows to corrupt and restore a particular kernel partition
     (designated by the partition name, A or B.
     '''
 
     # This value is used to alter contents of a byte in the appropriate kernel
     # image. First added to corrupt the image, then subtracted to restore the
     # image.
@@ skipping 72 matching lines @@
     def restore_kernel(self, section):
         '''Restore the previously corrupted kernel.'''
         self._modify_kernel(section.upper(), -self.DELTA)
 
     def get_version(self, section):
         '''Return version read from this section blob's header.'''
         return self.partition_map[section.upper()]['version']
 
     def set_version(self, section, version):
         '''Set version of this kernel blob and re-sign it.'''
+        if version < 0:
+            raise KernelHandlerError('Bad version value %d' % version)
         self._modify_kernel(section.upper(), version, KERNEL_VERSION_MOD)
 
     def init (self, chros_if):
         '''Initialize the kernel handler object.
 
         Input argument is a ChromeOS interface object reference.
         '''
         self.chros_if = chros_if
         self.dump_file_name = chros_if.state_dir_file(TMP_FILE_NAME)
         self._get_partition_map()