T5195: vyos.util -> vyos.utils package refactoring (#2093)

* T5195: move run, cmd, call, rc_cmd helper to vyos.utils.process

* T5195: use read_file and write_file implementation from vyos.utils.file

Changed code automatically using:

find . -type f -not -path '*/\.*' -exec sed -i 's/^from vyos.util import read_file$/from vyos.utils.file import read_file/g' {} +
find . -type f -not -path '*/\.*' -exec sed -i 's/^from vyos.util import write_file$/from vyos.utils.file import write_file/g' {} +

* T5195: move chmod* helpers to vyos.utils.permission

* T5195: use colon_separated_to_dict from vyos.utils.dict

* T5195: move is_systemd_service_* to vyos.utils.process

* T5195: fix boot issues with missing imports

* T5195: move dict_search_* helpers to vyos.utils.dict

* T5195: move network helpers to vyos.utils.network

* T5195: move commit_* helpers to vyos.utils.commit

* T5195: move user I/O helpers to vyos.utils.io

1 files changed, 60 insertions, 0 deletions

diff --git a/python/vyos/utils/commit.py b/python/vyos/utils/commit.py
new file mode 100644
index 000000000..105aed8c2
--- /dev/null
+++ b/python/vyos/utils/commit.py
@@ -0,0 +1,60 @@
+# 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/>.
+
+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 as err:
+            # 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)