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# Copyright 2023 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/>.
import os
from subprocess import run
def sysctl_read(name: str) -> str:
"""Read and return current value of sysctl() option
Args:
name (str): sysctl key name
Returns:
str: sysctl key value
"""
tmp = run(['sysctl', '-nb', name], capture_output=True)
return tmp.stdout.decode()
def sysctl_write(name: str, value: str | int) -> bool:
"""Change value via sysctl()
Args:
name (str): sysctl key name
value (str | int): sysctl key value
Returns:
bool: True if changed, False otherwise
"""
# convert other types to string before comparison
if not isinstance(value, str):
value = str(value)
# do not change anything if a value is already configured
if sysctl_read(name) == value:
return True
# return False if sysctl call failed
if run(['sysctl', '-wq', f'{name}={value}']).returncode != 0:
return False
# compare old and new values
# sysctl may apply value, but its actual value will be
# different from requested
if sysctl_read(name) == value:
return True
# False in other cases
return False
def sysctl_apply(sysctl_dict: dict[str, str], revert: bool = True) -> bool:
"""Apply sysctl values.
Args:
sysctl_dict (dict[str, str]): dictionary with sysctl keys with values
revert (bool, optional): Revert to original values if new were not
applied. Defaults to True.
Returns:
bool: True if all params configured properly, False in other cases
"""
# get current values
sysctl_original: dict[str, str] = {}
for key_name in sysctl_dict.keys():
sysctl_original[key_name] = sysctl_read(key_name)
# apply new values and revert in case one of them was not applied
for key_name, value in sysctl_dict.items():
if not sysctl_write(key_name, value):
if revert:
sysctl_apply(sysctl_original, revert=False)
return False
# everything applied
return True
def get_half_cpus():
""" return 1/2 of the numbers of available CPUs """
cpu = os.cpu_count()
if cpu > 1:
cpu /= 2
return int(cpu)
def find_device_file(device):
""" Recurively search /dev for the given device file and return its full path.
If no device file was found 'None' is returned """
from fnmatch import fnmatch
for root, dirs, files in os.walk('/dev'):
for basename in files:
if fnmatch(basename, device):
return os.path.join(root, basename)
return None
def load_as_module(name: str, path: str):
import importlib.util
spec = importlib.util.spec_from_file_location(name, path)
mod = importlib.util.module_from_spec(spec)
spec.loader.exec_module(mod)
return mod
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