tegwick
c96b0c6d88
Assistant: codex Assistant-Model: gpt-6.1-sol Assistant-Session: 01a126e1-76f8-7643-8cf3-e93336539ade
95 lines
4.5 KiB
Python
95 lines
4.5 KiB
Python
"""Pre-open schema/integrity/count proof; stdlib only, never constructs Store."""
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import argparse
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from contextlib import closing
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import hashlib
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import os
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import re
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import stat
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import json
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from pathlib import Path
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import sqlite3
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def inspect_readonly(path, *, _closed_snapshot=False):
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path = Path(path)
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if not path.is_file() or path.is_symlink():
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raise ValueError('existing nonsymlink private database required')
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uri = path.resolve().as_uri() + '?mode=ro' + ('&immutable=1' if _closed_snapshot else '')
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# sqlite3.Connection context management ends transactions; it does not close.
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with closing(sqlite3.connect(uri, uri=True, timeout=5)) as db:
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db.execute('PRAGMA query_only=ON')
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db.execute('BEGIN')
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version = db.execute('PRAGMA user_version').fetchone()[0]
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if version != 5:
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raise ValueError('pre-open database is not schema5; refuse migration')
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if db.execute('PRAGMA integrity_check').fetchall() != [('ok',)]:
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raise ValueError('read-only integrity check refused')
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lifecycle = {name: db.execute('SELECT COUNT(*) FROM ' + table).fetchone()[0]
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for name, table in (('records', 'lifecycle_records'),
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('events', 'lifecycle_events'),
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('pending', 'lifecycle_pending'))}
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result = {'schema_version': version, 'lifecycle': lifecycle,
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'outbox': dict(db.execute('SELECT state,COUNT(*) FROM outbox GROUP BY state')),
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'submissions': dict(db.execute('SELECT state,COUNT(*) FROM submissions GROUP BY state')),
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'integrity': 'ok', 'read_only_pre_open': True, 'store_constructed': False}
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db.rollback()
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return result
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def inspect_closed_snapshot(path, expected_sha256):
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"""Only a privately retained, frozen main-file snapshot with no WAL frames.
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Caller must establish exclusive snapshot creation/admin exit/no writer, and
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supply the recorded frozen main digest. Never use for the live database.
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Immutable SQLite reads ignore stale SHM and never create/change sidecars.
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Existing sidecars remain custody evidence; nothing is deleted/checkpointed.
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"""
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path = Path(path)
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if re.fullmatch(r'[0-9a-f]{64}', expected_sha256) is None:
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raise ValueError('exact frozen snapshot digest required')
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def metadata(target):
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info = target.lstat()
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if not stat.S_ISREG(info.st_mode) or stat.S_IMODE(info.st_mode) != 0o600 or info.st_nlink != 1:
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raise ValueError('private single-link snapshot custody required')
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return info
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main = metadata(path)
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if not 0 < main.st_size <= 512 * 1024**2:
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raise ValueError('bounded frozen snapshot required')
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def sidecars():
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identities = {}
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for suffix in ('-wal', '-shm'):
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target = Path(str(path) + suffix)
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if os.path.lexists(target):
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info = metadata(target)
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if info.st_uid != main.st_uid or info.st_gid != main.st_gid:
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raise ValueError('snapshot sidecar custody changed')
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if suffix == '-wal' and info.st_size != 0:
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raise ValueError('snapshot has WAL frames; immutable read refused')
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identities[suffix] = (info.st_dev, info.st_ino, info.st_size, info.st_mtime_ns)
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return identities
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before_sidecars = sidecars()
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def digest():
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value = hashlib.sha256()
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with path.open('rb') as stream:
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for block in iter(lambda: stream.read(1024**2), b''):
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value.update(block)
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return value.hexdigest()
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if digest() != expected_sha256:
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raise ValueError('frozen main-file digest changed before inspection')
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proof = inspect_readonly(path, _closed_snapshot=True)
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after = metadata(path)
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if (after.st_dev, after.st_ino, after.st_uid, after.st_gid, after.st_size) != (main.st_dev, main.st_ino, main.st_uid, main.st_gid, main.st_size):
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raise ValueError('frozen main-file identity changed')
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if digest() != expected_sha256 or sidecars() != before_sidecars:
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raise ValueError('frozen snapshot changed during inspection')
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return proof
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if __name__ == '__main__':
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parser = argparse.ArgumentParser(description=__doc__)
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parser.add_argument('--db', type=Path, required=True)
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args = parser.parse_args()
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try:
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print(json.dumps(inspect_readonly(args.db), sort_keys=True))
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except Exception:
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raise SystemExit('read-only schema5/integrity/count gate refused; no Store/admin open') from None
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