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firestar5683
64 lines
2.0 KiB
Python
64 lines
2.0 KiB
Python
"""Bounded cleanup of entries in an already opened storage-owner directory."""
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import os
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import stat
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class DeletionLimit(Exception):
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pass
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def remove_entry(directory, name, budget, *, depth=0):
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if name in ('', '.', '..') or '/' in name or '\\' in name or '\0' in name:
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raise ValueError('Invalid stored artifact name')
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if budget[0] <= 0 or depth > 8:
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raise DeletionLimit('Stored artifact cleanup limit reached')
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budget[0] -= 1
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try:
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info = os.stat(name, dir_fd=directory, follow_symlinks=False)
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except FileNotFoundError:
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return
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if stat.S_ISDIR(info.st_mode):
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child = os.open(name, os.O_RDONLY | os.O_DIRECTORY | os.O_NOFOLLOW, dir_fd=directory)
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try:
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opened = os.fstat(child)
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if (opened.st_dev, opened.st_ino) != (info.st_dev, info.st_ino):
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raise OSError('Stored artifact changed')
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with os.scandir(child) as entries:
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for entry in entries:
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remove_entry(child, entry.name, budget, depth=depth + 1)
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os.fsync(child)
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finally:
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os.close(child)
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os.rmdir(name, dir_fd=directory)
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else:
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# Unlink a symlink itself, never its target; hard links likewise stay bounded.
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os.unlink(name, dir_fd=directory)
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def usage(directory, *, budget=None, depth=0):
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budget = [4096] if budget is None else budget
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total = 0
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incomplete = False
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with os.scandir(directory) as entries:
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for entry in entries:
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if entry.name == '.lock':
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continue
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if budget[0] <= 0 or depth > 8:
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return total, True
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budget[0] -= 1
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try:
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info = entry.stat(follow_symlinks=False)
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if stat.S_ISREG(info.st_mode):
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total += info.st_size
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elif stat.S_ISDIR(info.st_mode):
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child = os.open(entry.name, os.O_RDONLY | os.O_DIRECTORY | os.O_NOFOLLOW, dir_fd=directory)
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try:
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size, partial = usage(child, budget=budget, depth=depth + 1)
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total += size
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incomplete |= partial
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finally:
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os.close(child)
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except OSError:
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incomplete = True
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return total, incomplete
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