Check the two files to ensure the present of Ethernet device and fix bug

client/site_tests/hardware_Components/hardware_Components.py

 # 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.
 
 import logging, os, pprint, re
 from autotest_lib.client.bin import test, utils
 from autotest_lib.client.common_lib import error
 
 
 class hardware_Components(test.test):
@@ skipping 78 matching lines @@
         return part_id
 
 
     def get_part_id_ethernet(self):
         """
           Returns a colon delimited string where the first section
           is the vendor id and the second section is the device id.
         """
         # Ethernet is optional so mark it as not present. A human
         # operator needs to decide if this is acceptable or not.
-        if not os.path.exists('/sys/class/net/eth0'):
-            return self._not_present
-        part_id = utils.read_one_line('/sys/class/net/eth0/device/device')
-        vendor_id = utils.read_one_line('/sys/class/net/eth0/device/vendor')
-        return "%s:%s" % (vendor_id.replace('0x',''), part_id.replace('0x',''))
+        vendor_file = '/sys/class/net/eth0/device/vendor'
+        part_file = '/sys/class/net/eth0/device/device'
+        if os.path.exists(part_file) and os.path.exists(vendor_file):
+          vendor_id = utils.read_one_line(vendor_file).replace('0x', '')
+          part_id = utils.read_one_line(part_file).replace('0x', '')
+          return "%s:%s" % (vendor_id, part_id)
+        else:
+          return self._not_present
 
 
     def get_part_id_flash_chip(self):
         # example output:
         #  Found chip "Winbond W25x16" (2048 KB, FWH) at physical address 0xfe
         parts = []
         lines = utils.system_output('flashrom', ignore_status=True).split('\n')
         for line in lines:
           match = re.search(r'Found chip "(.*)" .* at physical address ', line)
           if match:
@@ skipping 28 matching lines @@
         if not self._approved.has_key(cid):
             raise error.TestFail('%s missing from database' % cid)
 
         approved_devices = self._approved[cid]
         if '*' in approved_devices:
             self._system[cid] = [ '*' ]
             return
 
         for device in approved_devices:
             try:
-                utils.system(cmd % device)
-                self._system[cid] = [ device ]
-                return
+                output = utils.system_output(cmd % device)
+                # If it shows something, means found.
+                if output:
+                  self._system[cid] = [ device ]
+                  return
             except:
                 pass
         self._failures[cid] = [ 'No match' ]
 
 
     def get_vendor_id_touchpad(self):
         cmd = 'grep -i Touchpad /proc/bus/input/devices | sed s/.\*=//'
         part_id = utils.system_output(cmd).strip('"')
         return part_id
 
@@ skipping 33 matching lines @@
         for cid in self._usb_cids:
             self.check_approved_part_id_existence(cid, type='usb')
 
         logging.debug('System: %s', self.pformat(self._system))
 
         outdb = os.path.join(self.resultsdir, 'system_components')
         utils.open_write_close(outdb, self.pformat(self._system))
 
         if self._failures:
             raise error.TestFail(self.pformat(self._failures))