ec7f56c1b2
During the creation of a disk image (e.g. for a VM), there is the need to create, setup, configure and afterwards detach some kind of storage where the newly installed OS can be copied to or directly installed in. This patch implements partitioning handling. Change-Id: I0ca6a4ae3a2684d473b44e5f332ee4225ee30f8c Signed-off-by: Andreas Florath <andreas@florath.net>
83 lines
2.6 KiB
Python
83 lines
2.6 KiB
Python
# Copyright 2016 Andreas Florath (andreas@florath.net)
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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 re
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SIZE_UNIT_SPECS = [
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["TiB", 1024**4],
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["GiB", 1024**3],
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["MiB", 1024**2],
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["KiB", 1024**1],
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["TB", 1000**4],
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["GB", 1000**3],
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["MB", 1000**2],
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["KB", 1000**1],
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["T", 1000**4],
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["G", 1000**3],
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["M", 1000**2],
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["K", 1000**1],
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["B", 1],
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["", 1], # No unit -> size is given in bytes
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]
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# Basic RE to check and split floats (without exponent)
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# and a given unit specification (which must be non-numerical).
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size_unit_spec_re = re.compile("^([\d\.]*) ?([a-zA-Z0-9_]*)$")
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def _split_size_unit_spec(size_unit_spec):
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"""Helper function to split unit specification into parts.
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The first part is the numeric part - the second one is the unit.
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"""
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match = size_unit_spec_re.match(size_unit_spec)
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if match is None:
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raise RuntimeError("Invalid size unit spec [%s]" % size_unit_spec)
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return match.group(1), match.group(2)
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def _get_unit_factor(unit_str):
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"""Helper function to get the unit factor.
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The given unit_str needs to be a string of the
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SIZE_UNIT_SPECS table.
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If the unit is not found, a runtime error is raised.
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"""
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for spec_key, spec_value in SIZE_UNIT_SPECS:
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if unit_str == spec_key:
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return spec_value
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raise RuntimeError("unit_str [%s] not known" % unit_str)
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def parse_abs_size_spec(size_spec):
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size_cnt_str, size_unit_str = _split_size_unit_spec(size_spec)
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unit_factor = _get_unit_factor(size_unit_str)
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return int(unit_factor * (
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float(size_cnt_str) if len(size_cnt_str) > 0 else 1))
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def parse_rel_size_spec(size_spec, abs_size):
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"""Parses size specifications - can be relative like 50%
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In addition to the absolute parsing also a relative
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parsing is done. If the size specification ends in '%',
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then the relative size of the given 'abs_size' is returned.
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"""
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if size_spec[-1] == '%':
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percent = float(size_spec[:-1])
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return True, int(abs_size * percent / 100.0)
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return False, parse_abs_size_spec(size_spec)
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