95 lines
2.7 KiB
Python
95 lines
2.7 KiB
Python
#!/usr/bin/python
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# Copyright 2016 Sam Yaple
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# Copied and licensed from https://github.com/SamYaple/osdk
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from hashlib import sha1
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from osdk import osdk
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from uuid import uuid4 as uuid
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def get_disk_size(device):
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with open(device, 'rb') as f:
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return f.seek(0, 2)
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def read_segments(f, lst, size, o):
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zero_hash = sha1(bytes([0] * size)).hexdigest()
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for segment in lst:
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f.seek(segment * size, 0)
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data = f.read(size)
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if not data:
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raise Exception('Failed to read data')
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sha1_hash = sha1(data)
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if sha1_hash.hexdigest() != zero_hash:
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meta = dict()
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meta['incremental'] = o.metadata['incremental']
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meta['base'] = len(o.metadata['bases']) - 1
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meta['encryption'] = 0
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meta['compression'] = 0
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meta['sha1_hash'] = sha1_hash.digest()
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o.segments[segment] = meta
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else:
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try:
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del o.segments[segment]
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except KeyError:
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pass
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def main():
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device = '/dev/loop0'
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old_manifest = 'manifest0.osdk'
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manifest = 'manifest0.osdk'
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manifest = 'manifest1.osdk'
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segment_size = 4 * 1024**2 # 4MiB
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size_of_disk = get_disk_size(device)
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num_of_sectors = int(size_of_disk / 512)
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num_of_segments = int(size_of_disk / segment_size)
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o = osdk(manifest)
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o.metadata['sectors'] = num_of_sectors
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new = True
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new = False
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existing = True
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existing_full = True
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existing_full = False
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if new:
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o.metadata['incremental'] = 0
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o.metadata['segment_size'] = segment_size
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o.metadata['bases'] = [uuid().bytes]
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segments_to_read = range(0, num_of_segments - 1)
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elif existing:
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o.read_manifest(old_manifest)
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o.metadata['incremental'] += 1
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segments_to_read = range(1, num_of_segments - 1)
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elif existing_full:
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o.read_manifest(old_manifest)
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o.metadata['incremental'] += 1
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segments_to_read = range(0, num_of_segments - 1)
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with open(device, 'rb+') as f:
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read_segments(f, segments_to_read, segment_size, o)
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o.write_manifest()
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if __name__ == '__main__':
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main()
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