44 lines
2.3 KiB
Python
44 lines
2.3 KiB
Python
# SPDX-License-Identifier: MPL-2.0
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"""Validate an inventoried, single-extent Sargo userdata mapping."""
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import re
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def mount_table(layout):
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device = layout.get('device')
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if device != '/dev/mmcblk0p72':
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raise ValueError('Expected Sargo userdata, not another partition')
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if not re.fullmatch(r'[0-9a-f]{64}', layout.get('firstMiBSha256', '')):
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raise ValueError('Missing userdata identity checksum')
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if layout.get('schema') == 2 and layout.get('table') == 'direct':
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if (layout.get('partitionLabel') != 'userdata' or
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layout.get('filesystem') != 'ext4' or
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layout.get('storage') != 'raw-userdata-ext4' or
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not re.fullmatch(r'[0-9]+:[0-9]+', layout.get('backingDevice', '')) or
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not re.fullmatch(r'[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}',
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layout.get('filesystemUuid', ''))):
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raise ValueError('Direct mapping requires inventoried raw ext4 userdata')
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size = int(layout.get('size', 0))
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if size <= 0 or size % 512:
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raise ValueError('Invalid direct userdata geometry')
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return None
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match = re.fullmatch(r'0 ([0-9]+) linear ([0-9]+:[0-9]+) ([0-9]+)',
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layout.get('table', ''))
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if not match:
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raise ValueError('Only a single linear extent is supported')
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sectors, backing, offset = int(match[1]), match[2], int(match[3])
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size = int(layout['size'])
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if size <= 0 or size % 512 or sectors <= 0 or offset < 2048:
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raise ValueError('Invalid userdata extent geometry')
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if (sectors + offset) * 512 > size:
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raise ValueError('Extent exceeds userdata')
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if layout.get('schema') == 2:
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if (layout.get('partitionLabel') != 'userdata' or
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layout.get('filesystem') != 'ext4' or
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layout.get('backingDevice') != backing):
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raise ValueError('Mapping must be ext4 on the inventoried userdata device')
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elif not (layout['table'] == '0 104448000 linear 259:40 329728'
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and size == 53648801280):
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raise ValueError('A new layout requires a schema 2 inventory')
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# Kernel major/minor numbers can change between boots. The partition path
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# is stable with this Sargo kernel, and its first MiB is checked before use.
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return f'0 {sectors} linear {device} {offset}'
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