smart device name wrapper function rockstor#1206

Takes a device name, ie base device or partition and returns the
first match found in lsblk by way of finding the base device. This
leaves base devices as is and partition devices translated to their
base device which can help to provide better smart command
error reporting.

src/rockstor/system/smart.py

@@ -28,6 +28,7 @@
 
 SMART = '/usr/sbin/smartctl'
 CAT = '/usr/bin/cat'
+LSBLK = '/usr/bin/lsblk'
 # enables reading file dumps of smartctl output instead of running smartctl
 # currently hardwired to read from eg:- /root/smartdumps/smart-H--info.out
 # default setting = False
@@ -227,7 +228,7 @@ def test_logs(device, test_mode=TESTMODE):
     :return: test_d as a dictionary of summarized test
     """
     smart_command = [SMART, '-l', 'selftest', '-l', 'selective', '/dev/%s'
-                     % device]
+                     % get_base_device(device)]
     if not test_mode:
         o, e, rc = run_command(smart_command, throw=False)
     else:
@@ -341,3 +342,39 @@ def screen_return_codes(msg_on_hit, return_code_target, o, e, rc, command):
                  '%s error: %s' % (rc, command, o, e))
         logger.error(e_msg)
         raise CommandException(('%s' % command), o, e, rc)
+
+
+def get_base_device(device, test_mode=TESTMODE):
+    """
+    Helper function that returns the base device of a partition or if given
+    a base device then will return it as is;
+    ie
+    input sda3 output sda
+    input sda output sda
+    Works as a function of lsblk list order ie base devices first. So we return
+    the first start of line match to our supplied device name with the pattern
+    as the first element in lsblk's output and the match target as our device.
+    :param device: device name as per db entry, ie as returned from scan_disks
+    :return: base_dev: the root device ie device = sda3 base_dev = sda or None
+    if no lsblk entry was found to match.
+    """
+    base_dev = None
+    if not test_mode:
+        out, e, rc = run_command([LSBLK])
+    else:
+        out, e, rc = run_command([CAT, '/root/smartdumps/lsblk.out'])
+    # now examine the output from lsblk line by line
+    for line in out:
+        line_fields = line.split()
+        if len(line_fields) < 1:
+            # skip empty lines
+            logger.debug('get_base_device skipped an empty line')
+            continue
+        if re.match(line_fields[0], device):
+            # We have found a device string match to our device so
+            logger.debug('get_base_device found a match in lsblk out for '
+                         'device %s in line %s' % (device, line))
+            base_dev = line_fields[0]
+            break
+    # return base_dev which should now be None or first character matches
+    return base_dev