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-rw-r--r--python/vyos/utils/file.py171
1 files changed, 171 insertions, 0 deletions
diff --git a/python/vyos/utils/file.py b/python/vyos/utils/file.py
new file mode 100644
index 000000000..2560a35be
--- /dev/null
+++ b/python/vyos/utils/file.py
@@ -0,0 +1,171 @@
+# 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
+
+
+def read_file(fname, defaultonfailure=None):
+ """
+ read the content of a file, stripping any end characters (space, newlines)
+ should defaultonfailure be not None, it is returned on failure to read
+ """
+ try:
+ """ Read a file to string """
+ with open(fname, 'r') as f:
+ data = f.read().strip()
+ return data
+ except Exception as e:
+ if defaultonfailure is not None:
+ return defaultonfailure
+ raise e
+
+def write_file(fname, data, defaultonfailure=None, user=None, group=None, mode=None, append=False):
+ """
+ Write content of data to given fname, should defaultonfailure be not None,
+ it is returned on failure to read.
+
+ If directory of file is not present, it is auto-created.
+ """
+ dirname = os.path.dirname(fname)
+ if not os.path.isdir(dirname):
+ os.makedirs(dirname, mode=0o755, exist_ok=False)
+ chown(dirname, user, group)
+
+ try:
+ """ Write a file to string """
+ bytes = 0
+ with open(fname, 'w' if not append else 'a') as f:
+ bytes = f.write(data)
+ chown(fname, user, group)
+ chmod(fname, mode)
+ return bytes
+ except Exception as e:
+ if defaultonfailure is not None:
+ return defaultonfailure
+ raise e
+
+def read_json(fname, defaultonfailure=None):
+ """
+ read and json decode the content of a file
+ should defaultonfailure be not None, it is returned on failure to read
+ """
+ import json
+ try:
+ with open(fname, 'r') as f:
+ data = json.load(f)
+ return data
+ except Exception as e:
+ if defaultonfailure is not None:
+ return defaultonfailure
+ raise e
+
+def chown(path, user, group):
+ """ change file/directory owner """
+ from pwd import getpwnam
+ from grp import getgrnam
+
+ if user is None or group is None:
+ return False
+
+ # path may also be an open file descriptor
+ if not isinstance(path, int) and not os.path.exists(path):
+ return False
+
+ uid = getpwnam(user).pw_uid
+ gid = getgrnam(group).gr_gid
+ os.chown(path, uid, gid)
+ return True
+
+
+def chmod(path, bitmask):
+ # path may also be an open file descriptor
+ if not isinstance(path, int) and not os.path.exists(path):
+ return
+ if bitmask is None:
+ return
+ os.chmod(path, bitmask)
+
+
+def chmod_600(path):
+ """ Make file only read/writable by owner """
+ from stat import S_IRUSR, S_IWUSR
+
+ bitmask = S_IRUSR | S_IWUSR
+ chmod(path, bitmask)
+
+
+def chmod_750(path):
+ """ Make file/directory only executable to user and group """
+ from stat import S_IRUSR, S_IWUSR, S_IXUSR, S_IRGRP, S_IXGRP
+
+ bitmask = S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IXGRP
+ chmod(path, bitmask)
+
+
+def chmod_755(path):
+ """ Make file executable by all """
+ from stat import S_IRUSR, S_IWUSR, S_IXUSR, S_IRGRP, S_IXGRP, S_IROTH, S_IXOTH
+
+ bitmask = S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IXGRP | \
+ S_IROTH | S_IXOTH
+ chmod(path, bitmask)
+
+
+def makedir(path, user=None, group=None):
+ if os.path.exists(path):
+ return
+ os.makedirs(path, mode=0o755)
+ chown(path, user, group)
+
+def wait_for_inotify(file_path, pre_hook=None, event_type=None, timeout=None, sleep_interval=0.1):
+ """ Waits for an inotify event to occur """
+ if not os.path.dirname(file_path):
+ raise ValueError(
+ "File path {} does not have a directory part (required for inotify watching)".format(file_path))
+ if not os.path.basename(file_path):
+ raise ValueError(
+ "File path {} does not have a file part, do not know what to watch for".format(file_path))
+
+ from inotify.adapters import Inotify
+ from time import time
+ from time import sleep
+
+ time_start = time()
+
+ i = Inotify()
+ i.add_watch(os.path.dirname(file_path))
+
+ if pre_hook:
+ pre_hook()
+
+ for event in i.event_gen(yield_nones=True):
+ if (timeout is not None) and ((time() - time_start) > timeout):
+ # If the function didn't return until this point,
+ # the file failed to have been written to and closed within the timeout
+ raise OSError("Waiting for file {} to be written has failed".format(file_path))
+
+ # Most such events don't take much time, so it's better to check right away
+ # and sleep later.
+ if event is not None:
+ (_, type_names, path, filename) = event
+ if filename == os.path.basename(file_path):
+ if event_type in type_names:
+ return
+ sleep(sleep_interval)
+
+def wait_for_file_write_complete(file_path, pre_hook=None, timeout=None, sleep_interval=0.1):
+ """ Waits for a process to close a file after opening it in write mode. """
+ wait_for_inotify(file_path,
+ event_type='IN_CLOSE_WRITE', pre_hook=pre_hook, timeout=timeout, sleep_interval=sleep_interval)