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-rw-r--r--python/vyos/utils/system.py82
1 files changed, 82 insertions, 0 deletions
diff --git a/python/vyos/utils/system.py b/python/vyos/utils/system.py
new file mode 100644
index 000000000..7102d5985
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+++ b/python/vyos/utils/system.py
@@ -0,0 +1,82 @@
+# 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/>.
+
+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