b38dea0597
Share Gaia assets and adapters, keep private profiles and development documents local, and update both public READMEs.
32 lines
1.6 KiB
Python
32 lines
1.6 KiB
Python
#!/usr/bin/env python3
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# SPDX-License-Identifier: MPL-2.0
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"""Read and validate both GPT copies on the inventoried 64 GB Sargo; no writes."""
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import base64,json,struct,zlib
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from pathlib import Path
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def read_gpt():
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result={}
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with open('/dev/mmcblk0','rb',buffering=0) as disk:
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for name,lba in [('primary',1),('secondary',122142719)]:
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disk.seek(lba*512);h=disk.read(512)
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assert h[:8]==b'EFI PART'
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length,crc=struct.unpack_from('<II',h,12)
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assert 92<=length<=512
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check=bytearray(h[:length]);check[16:20]=b'\0'*4
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assert zlib.crc32(check)==crc
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current,other,first,last=struct.unpack_from('<QQQQ',h,24)
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assert current==lba and {current,other}=={1,122142719}
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entries,count,size,crc=struct.unpack_from('<QIII',h,72)
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assert count==72 and size==128
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disk.seek(entries*512);table=disk.read(count*size)
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assert len(table)==count*size and zlib.crc32(table)==crc
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parts={}
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for i in range(count):
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e=table[i*size:(i+1)*size]
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label=e[56:128].decode('utf-16le').rstrip('\0')
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if label:parts[label]={'index':i+1,'attributes':struct.unpack_from('<Q',e,48)[0]}
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result[name]={'headerLba':lba,'entriesLba':entries,'header':base64.b64encode(h).decode(),'table':base64.b64encode(table).decode(),'partitions':parts}
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assert result['primary']['table']==result['secondary']['table']
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result['bootId']=Path('/proc/sys/kernel/random/boot_id').read_text().strip()
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return result
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print(json.dumps(read_gpt()))
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