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# Copyright 2023-2025 VyOS maintainers and contributors <maintainers@vyos.io>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library. If not, see <http://www.gnu.org/licenses/>.
# pylint: disable=import-outside-toplevel
from typing import IO
def commit_in_progress():
"""Not to be used in normal op mode scripts!"""
# The CStore backend locks the config by opening a file
# The file is not removed after commit, so just checking
# if it exists is insufficient, we need to know if it's open by anyone
# There are two ways to check if any other process keeps a file open.
# The first one is to try opening it and see if the OS objects.
# That's faster but prone to race conditions and can be intrusive.
# The other one is to actually check if any process keeps it open.
# It's non-intrusive but needs root permissions, else you can't check
# processes of other users.
#
# Since this will be used in scripts that modify the config outside of the CLI
# framework, those knowingly have root permissions.
# For everything else, we add a safeguard.
from psutil import process_iter
from psutil import NoSuchProcess
from getpass import getuser
from vyos.defaults import commit_lock
if getuser() != 'root':
raise OSError(
'This functions needs to be run as root to return correct results!'
)
for proc in process_iter():
try:
files = proc.open_files()
if files:
for f in files:
if f.path == commit_lock:
return True
except NoSuchProcess:
# Process died before we could examine it
pass
# Default case
return False
def wait_for_commit_lock():
"""Not to be used in normal op mode scripts!"""
from time import sleep
# Very synchronous approach to multiprocessing
while commit_in_progress():
sleep(1)
# For transitional compatibility with the legacy commit locking mechanism,
# we require a lockf/fcntl (POSIX-type) lock, hence the following in place
# of vyos.utils.locking
def acquire_commit_lock_file() -> tuple[IO, str]:
import fcntl
from pathlib import Path
from vyos.defaults import commit_lock
try:
# pylint: disable=consider-using-with
lock_fd = Path(commit_lock).open('w')
except IOError as e:
out = f'Critical error opening commit lock file {e}'
return None, out
try:
fcntl.lockf(lock_fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
return lock_fd, ''
except IOError:
out = 'Configuration system locked by another commit in progress'
lock_fd.close()
return None, out
def release_commit_lock_file(file_descr):
import fcntl
if file_descr is None:
return
fcntl.lockf(file_descr, fcntl.LOCK_UN)
file_descr.close()
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