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'''
Implements the base CFSNode class and a few inherited variants.
This file is part of RTSLib.
Copyright (c) 2011-2013 by Datera, Inc
Copyright (c) 2011-2014 by Red Hat, Inc.
Licensed under the Apache License, Version 2.0 (the "License"); you may
not use this file except in compliance with the License. You may obtain
a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations
under the License.
'''
import os
import stat
from .utils import fread, fwrite, RTSLibError, RTSLibNotInCFS
class CFSNode(object):
# Where is the configfs base LIO directory ?
configfs_dir = '/sys/kernel/config/target'
# CFSNode private stuff
def __init__(self):
self._path = self.configfs_dir
def __eq__(self, other):
return self._path == other._path
def __ne__(self, other):
return self._path != other._path
def _get_path(self):
return self._path
def _create_in_cfs_ine(self, mode):
'''
Creates the configFS node if it does not already exist, depending on
the mode.
any -> makes sure it exists, also works if the node already does exist
lookup -> make sure it does NOT exist
create -> create the node which must not exist beforehand
'''
if mode not in ['any', 'lookup', 'create']:
raise RTSLibError("Invalid mode: %s" % mode)
if self.exists and mode == 'create':
raise RTSLibError("This %s already exists in configFS"
% self.__class__.__name__)
elif not self.exists and mode == 'lookup':
raise RTSLibNotInCFS("No such %s in configfs: %s"
% (self.__class__.__name__, self.path))
if not self.exists:
try:
os.mkdir(self.path)
except:
raise RTSLibError("Could not create %s in configFS"
% self.__class__.__name__)
def _exists(self):
return os.path.isdir(self.path)
def _check_self(self):
if not self.exists:
raise RTSLibNotInCFS("This %s does not exist in configFS"
% self.__class__.__name__)
def _list_files(self, path, writable=None):
'''
List files under a path depending on their owner's write permissions.
@param path: The path under which the files are expected to be. If the
path itself is not a directory, an empty list will be returned.
@type path: str
@param writable: If None (default), returns all parameters, if True,
returns read-write parameters, if False, returns just the read-only
parameters.
@type writable: bool or None
@return: List of file names filtered according to their write perms.
'''
if not os.path.isdir(path):
return []
if writable is None:
names = os.listdir(path)
elif writable:
names = [name for name in os.listdir(path)
if (os.stat("%s/%s" % (path, name))[stat.ST_MODE] \
& stat.S_IWUSR)]
else:
names = [os.path.basename(name) for name in os.listdir(path)
if not (os.stat("%s/%s" % (path, name))[stat.ST_MODE] \
& stat.S_IWUSR)]
names.sort()
return names
# CFSNode public stuff
def list_parameters(self, writable=None):
'''
@param writable: If None (default), returns all parameters, if True,
returns read-write parameters, if False, returns just the read-only
parameters.
@type writable: bool or None
@return: The list of existing RFC-3720 parameter names.
'''
self._check_self()
path = "%s/param" % self.path
return self._list_files(path, writable)
def list_attributes(self, writable=None):
'''
@param writable: If None (default), returns all attributes, if True,
returns read-write attributes, if False, returns just the read-only
attributes.
@type writable: bool or None
@return: A list of existing attribute names as strings.
'''
self._check_self()
path = "%s/attrib" % self.path
return self._list_files(path, writable)
def set_attribute(self, attribute, value):
'''
Sets the value of a named attribute.
The attribute must exist in configFS.
@param attribute: The attribute's name. It is case-sensitive.
@type attribute: string
@param value: The attribute's value.
@type value: string
'''
self._check_self()
path = "%s/attrib/%s" % (self.path, str(attribute))
if not os.path.isfile(path):
raise RTSLibError("Cannot find attribute: %s"
% str(attribute))
else:
try:
fwrite(path, "%s" % str(value))
except Exception as e:
raise RTSLibError("Cannot set attribute %s: %s" % (attribute, e))
def get_attribute(self, attribute):
'''
@param attribute: The attribute's name. It is case-sensitive.
@return: The named attribute's value, as a string.
'''
self._check_self()
path = "%s/attrib/%s" % (self.path, str(attribute))
if not os.path.isfile(path):
raise RTSLibError("Cannot find attribute: %s" % attribute)
else:
return fread(path)
def set_parameter(self, parameter, value):
'''
Sets the value of a named RFC-3720 parameter.
The parameter must exist in configFS.
@param parameter: The RFC-3720 parameter's name. It is case-sensitive.
@type parameter: string
@param value: The parameter's value.
@type value: string
'''
self._check_self()
path = "%s/param/%s" % (self.path, str(parameter))
if not os.path.isfile(path):
raise RTSLibError("Cannot find parameter: %s" % parameter)
else:
try:
fwrite(path, "%s\n" % str(value))
except Exception as e:
raise RTSLibError("Cannot set parameter %s: %s" % (parameter, e))
def get_parameter(self, parameter):
'''
@param parameter: The RFC-3720 parameter's name. It is case-sensitive.
@type parameter: string
@return: The named parameter value as a string.
'''
self._check_self()
path = "%s/param/%s" % (self.path, str(parameter))
if not os.path.isfile(path):
raise RTSLibError("Cannot find RFC-3720 parameter: %s" % parameter)
else:
return fread(path)
def delete(self):
'''
If the underlying configFS object does not exist, this method does
nothing. If the underlying configFS object exists, this method attempts
to delete it.
'''
if self.exists:
os.rmdir(self.path)
path = property(_get_path,
doc="Get the configFS object path.")
exists = property(_exists,
doc="Is True as long as the underlying configFS object exists. " \
+ "If the underlying configFS objects gets deleted " \
+ "either by calling the delete() method, or by any " \
+ "other means, it will be False.")
def dump(self):
d = {}
attrs = {}
params = {}
for item in self.list_attributes(writable=True):
attrs[item] = int(self.get_attribute(item))
if attrs:
d['attributes'] = attrs
for item in self.list_parameters(writable=True):
params[item] = self.get_parameter(item)
if params:
d['parameters'] = params
return d
def _test():
import doctest
doctest.testmod()
if __name__ == "__main__":
_test()
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