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

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fix possible cpld race access issue (#15371) Why I did it fix possible cpld race read issue between watchdog and reboot cause process How I did it Use fcntl.flock to limit parallel access to cpld sys file How to verify it It can be simulated and verified with following python script ``` python3 import fcntl import signal import threading exit_flag = False def get_cpld_reg_value(getreg_path, register): file = open(getreg_path, 'w+') # Acquire an exclusive lock on the file fcntl.flock(file, fcntl.LOCK_EX) try: file.write(register + '\n') 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 def cpld_read(thread_num, cpld_reg, expect_val): while not exit_flag: val = get_cpld_reg_value("/sys/devices/platform/dx010_cpld/getreg", cpld_reg) #print(f"Thread {thread_num}: get cpld reg {cpld_reg}, value {val}") if val != expect_val: print(f"Thread {thread_num}: get cpld reg {cpld_reg}, value {val}, expect_val {expect_val}") def signal_handler(sig, frame): global exit_flag print("Ctrl+C detected. Quitting...") exit_flag = True if __name__ == '__main__': # Register the signal handler for Ctrl+C signal.signal(signal.SIGINT, signal_handler) t1 = threading.Thread(target=cpld_read, args=(1, '0x103', '0x11',)) t2 = threading.Thread(target=cpld_read, args=(2, '0x141', '0x00',)) t1.start() t2.start() t1.join() t2.join() ```
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import fcntl
import os
import struct
import subprocess
from mmap import *
from sonic_py_common import device_info
HOST_CHK_CMD = ["docker"]
EMPTY_STRING = ""
class APIHelper():
def __init__(self):
(self.platform, self.hwsku) = device_info.get_platform_and_hwsku()
def is_host(self):
try:
subprocess.call(HOST_CHK_CMD, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
except FileNotFoundError:
return False
return True
def pci_get_value(self, resource, offset):
status = True
result = ""
try:
fd = os.open(resource, os.O_RDWR)
mm = mmap(fd, 0)
mm.seek(int(offset))
read_data_stream = mm.read(4)
result = struct.unpack('I', read_data_stream)
except:
status = False
return status, result
def run_command(self, cmd):
status = True
result = ""
try:
p = subprocess.Popen(
cmd, universal_newlines=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
raw_data, err = p.communicate()
if err == '':
result = raw_data.strip()
except:
status = False
return status, result
def read_txt_file(self, file_path):
try:
with open(file_path, 'r') as fd:
data = fd.read()
return data.strip()
except IOError:
pass
return None
def read_one_line_file(self, file_path):
try:
with open(file_path, 'r') as fd:
data = fd.readline()
return data.strip()
except IOError:
pass
return None
def write_txt_file(self, file_path, value):
try:
with open(file_path, 'w') as fd:
fd.write(str(value))
except Exception:
return False
return True
def get_cpld_reg_value(self, getreg_path, register):
fix possible cpld race access issue (#15371) Why I did it fix possible cpld race read issue between watchdog and reboot cause process How I did it Use fcntl.flock to limit parallel access to cpld sys file How to verify it It can be simulated and verified with following python script ``` python3 import fcntl import signal import threading exit_flag = False def get_cpld_reg_value(getreg_path, register): file = open(getreg_path, 'w+') # Acquire an exclusive lock on the file fcntl.flock(file, fcntl.LOCK_EX) try: file.write(register + '\n') 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 def cpld_read(thread_num, cpld_reg, expect_val): while not exit_flag: val = get_cpld_reg_value("/sys/devices/platform/dx010_cpld/getreg", cpld_reg) #print(f"Thread {thread_num}: get cpld reg {cpld_reg}, value {val}") if val != expect_val: print(f"Thread {thread_num}: get cpld reg {cpld_reg}, value {val}, expect_val {expect_val}") def signal_handler(sig, frame): global exit_flag print("Ctrl+C detected. Quitting...") exit_flag = True if __name__ == '__main__': # Register the signal handler for Ctrl+C signal.signal(signal.SIGINT, signal_handler) t1 = threading.Thread(target=cpld_read, args=(1, '0x103', '0x11',)) t2 = threading.Thread(target=cpld_read, args=(2, '0x141', '0x00',)) t1.start() t2.start() t1.join() t2.join() ```
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file = open(getreg_path, 'w+')
# Acquire an exclusive lock on the file
fcntl.flock(file, fcntl.LOCK_EX)
try:
file.write(register + '\n')
fix possible cpld race access issue (#15371) Why I did it fix possible cpld race read issue between watchdog and reboot cause process How I did it Use fcntl.flock to limit parallel access to cpld sys file How to verify it It can be simulated and verified with following python script ``` python3 import fcntl import signal import threading exit_flag = False def get_cpld_reg_value(getreg_path, register): file = open(getreg_path, 'w+') # Acquire an exclusive lock on the file fcntl.flock(file, fcntl.LOCK_EX) try: file.write(register + '\n') 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 def cpld_read(thread_num, cpld_reg, expect_val): while not exit_flag: val = get_cpld_reg_value("/sys/devices/platform/dx010_cpld/getreg", cpld_reg) #print(f"Thread {thread_num}: get cpld reg {cpld_reg}, value {val}") if val != expect_val: print(f"Thread {thread_num}: get cpld reg {cpld_reg}, value {val}, expect_val {expect_val}") def signal_handler(sig, frame): global exit_flag print("Ctrl+C detected. Quitting...") exit_flag = True if __name__ == '__main__': # Register the signal handler for Ctrl+C signal.signal(signal.SIGINT, signal_handler) t1 = threading.Thread(target=cpld_read, args=(1, '0x103', '0x11',)) t2 = threading.Thread(target=cpld_read, args=(2, '0x141', '0x00',)) t1.start() t2.start() t1.join() t2.join() ```
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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