[DX010] fix possible cpld race access issue

device/celestica/x86_64-cel_seastone-r0/sonic_platform/component.py

@@ -51,21 +51,13 @@ def __get_bios_version(self):
         except Exception as e:
             return None
 
-    def get_register_value(self, register):
-        # Retrieves the cpld register value
-        with open(GETREG_PATH, 'w') as file:
-            file.write(register + '\n')
-        with open(GETREG_PATH, 'r') as file:
-            raw_data = file.readline()
-        return raw_data.strip()
-
     def __get_cpld_version(self):
         # Retrieves the CPLD firmware version
         cpld_version = dict()
         for cpld_name in CPLD_ADDR_MAPPING:
             try:
                 cpld_addr = CPLD_ADDR_MAPPING[cpld_name]
-                cpld_version_raw = self.get_register_value(cpld_addr)
+                cpld_version_raw = self._api_helper.get_cpld_reg_value(GETREG_PATH, cpld_addr)
                 cpld_version_str = "{}.{}".format(int(cpld_version_raw[2], 16), int(
                     cpld_version_raw[3], 16)) if cpld_version_raw is not None else 'None'
                 cpld_version[cpld_name] = cpld_version_str

device/celestica/x86_64-cel_seastone-r0/sonic_platform/helper.py

@@ -1,3 +1,4 @@
+import fcntl
 import os
 import struct
 import subprocess
@@ -74,9 +75,23 @@ def write_txt_file(self, file_path, value):
         return True
 
     def get_cpld_reg_value(self, getreg_path, register):
-        with open(getreg_path, 'w') as file:
+        file = open(getreg_path, 'w+')
+        # Acquire an exclusive lock on the file
+        fcntl.flock(file, fcntl.LOCK_EX)
+
+        try:
             file.write(register + '\n')
-        with open(getreg_path, 'r') as file:
-            result = file.readline()
+            file.flush()
+
+            # Seek to the beginning of the file
+            file.seek(0)
+
+            # Read the content of the file
+            result = file.readline().strip()
+        finally:
+            # Release the lock and close the file
+            fcntl.flock(file, fcntl.LOCK_UN)
+            file.close()
+
         return result