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()
```
Signed-off-by: maipbui <maibui@microsoft.com>
Dependency: [PR (#12065)](https://github.com/sonic-net/sonic-buildimage/pull/12065) needs to merge first.
#### Why I did it
1. `eval()` - not secure against maliciously constructed input, can be dangerous if used to evaluate dynamic content. This may be a code injection vulnerability.
2. `subprocess()` - when using with `shell=True` is dangerous. Using subprocess function without a static string can lead to command injection.
3. `os` - not secure against maliciously constructed input and dangerous if used to evaluate dynamic content.
4. `is` operator - string comparison should not be used with reference equality.
5. `globals()` - extremely dangerous because it may allow an attacker to execute arbitrary code on the system
#### How I did it
1. `eval()` - use `literal_eval()`
2. `subprocess()` - use `shell=False` instead. use an array string. Ref: [https://semgrep.dev/docs/cheat-sheets/python-command-injection/#mitigation](https://semgrep.dev/docs/cheat-sheets/python-command-injection/#mitigation)
3. `os` - use with `subprocess`
4. `is` - replace by `==` operator for value equality
5. `globals()` - avoid the use of globals()
Submodule updates include the following commits:
* src/sonic-utilities 9dc58ea...f9eb739 (18):
> Remove unnecessary calls to str.encode() now that the package is Python 3; Fix deprecation warning (#1260)
> [generate_dump] Ignoring file/directory not found Errors (#1201)
> Fixed porstat rate and util issues (#1140)
> fix error: interface counters is mismatch after warm-reboot (#1099)
> Remove unnecessary calls to str.decode() now that the package is Python 3 (#1255)
> [acl-loader] Make list sorting compliant with Python 3 (#1257)
> Replace hard-coded fast-reboot with variable. And some typo corrections (#1254)
> [configlet][portconfig] Remove calls to dict.has_key() which is not available in Python 3 (#1247)
> Remove unnecessary conversions to list() and calls to dict.keys() (#1243)
> Clean up LGTM alerts (#1239)
> Add 'requests' as install dependency in setup.py (#1240)
> Convert to Python 3 (#1128)
> Fix mock SonicV2Connector in python3: use decode_responses mode so caller code will be the same as python2 (#1238)
> [tests] Do not trim from PATH if we did not append to it; Clean up/fix shebangs in scripts (#1233)
> Updates to bgp config and show commands with BGP_INTERNAL_NEIGHBOR table (#1224)
> [cli]: NAT show commands newline issue after migrated to Python3 (#1204)
> [doc]: Update Command-Reference.md (#1231)
> Added 'import sys' in feature.py file (#1232)
* src/sonic-py-swsssdk 9d9f0c6...1664be9 (2):
> Fix: no need to decode() after redis client scan, so it will work for both python2 and python3 (#96)
> FieldValueMap `contains`(`in`) will also work when migrated to libswsscommon(C++ with SWIG wrapper) (#94)
- Also fix Python 3-related issues:
- Use integer (floor) division in config_samples.py (sonic-config-engine)
- Replace print statement with print function in eeprom.py plugin for x86_64-kvm_x86_64-r0 platform
- Update all platform plugins to be compatible with both Python 2 and Python 3
- Remove shebangs from plugins files which are not intended to be executable
- Replace tabs with spaces in Python plugin files and fix alignment, because Python 3 is more strict
- Remove trailing whitespace from plugins files
As part of consolidating all common Python-based functionality into the new sonic-py-common package, this pull request:
1. Redirects all Python applications/scripts in sonic-buildimage repo which previously imported sonic_device_util or sonic_daemon_base to instead import sonic-py-common, which was added in https://github.com/Azure/sonic-buildimage/pull/5003
2. Replaces all calls to `sonic_device_util.get_platform_info()` to instead call `sonic_py_common.get_platform()` and removes any calls to `sonic_device_util.get_machine_info()` which are no longer necessary (i.e., those which were only used to pass the results to `sonic_device_util.get_platform_info()`.
3. Removes unused imports to the now-deprecated sonic-daemon-base package and sonic_device_util.py module
This is the next step toward resolving https://github.com/Azure/sonic-buildimage/issues/4999
Also reverted my previous change in which device_info.get_platform() would first try obtaining the platform ID string from Config DB and fall back to gathering it from machine.conf upon failure because this function is called by sonic-cfggen before the data is in the DB, in which case, the db_connect() call will hang indefinitely, which was not the behavior I expected. As of now, the function will always reference machine.conf.
