93 lines
3.0 KiB
Python
93 lines
3.0 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (c) 2011 OpenStack, LLC.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import ConfigParser
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import os
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import string
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from nova.rootwrap import filters
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class NoFilterMatched(Exception):
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"""This exception is raised when no filter matched."""
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pass
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class FilterMatchNotExecutable(Exception):
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"""
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This exception is raised when a filter matched but no executable was
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found.
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"""
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def __init__(self, match=None, **kwargs):
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self.match = match
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def build_filter(class_name, *args):
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"""Returns a filter object of class class_name"""
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if not hasattr(filters, class_name):
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# TODO(ttx): Log the error (whenever nova-rootwrap has a log file)
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return None
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filterclass = getattr(filters, class_name)
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return filterclass(*args)
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def load_filters(filters_path):
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"""Load filters from a list of directories"""
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filterlist = []
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for filterdir in filters_path:
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if not os.path.isdir(filterdir):
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continue
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for filterfile in os.listdir(filterdir):
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filterconfig = ConfigParser.RawConfigParser()
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filterconfig.read(os.path.join(filterdir, filterfile))
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for (name, value) in filterconfig.items("Filters"):
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filterdefinition = [string.strip(s) for s in value.split(',')]
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newfilter = build_filter(*filterdefinition)
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if newfilter is None:
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continue
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filterlist.append(newfilter)
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return filterlist
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def match_filter(filters, userargs, exec_dirs=[]):
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"""
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Checks user command and arguments through command filters and
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returns the first matching filter.
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Raises NoFilterMatched if no filter matched.
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Raises FilterMatchNotExecutable if no executable was found for the
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best filter match.
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"""
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first_not_executable_filter = None
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for f in filters:
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if f.match(userargs):
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# Try other filters if executable is absent
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if not f.get_exec(exec_dirs=exec_dirs):
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if not first_not_executable_filter:
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first_not_executable_filter = f
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continue
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# Otherwise return matching filter for execution
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return f
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if first_not_executable_filter:
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# A filter matched, but no executable was found for it
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raise FilterMatchNotExecutable(match=first_not_executable_filter)
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# No filter matched
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raise NoFilterMatched()
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