Eryk Sun added the comment:
Python 3's os.stat tries to open a handle for the file or directory in order to
call GetFileInformationByHandle. Opening a file handle via CreateFile requests
at least FILE_READ_ATTRIBUTES and SYNCHRONIZE access when it calls
NtCreateFile. If access is denied, os.stat is supposed to fall back on the
basic WIN32_FIND_DATA information from FindFirstFile. However, it's not working
as intended. For example:
>>> import os
>>> os.mkdir('test')
>>> os.system('icacls test /deny Users:(S,RA)')
processed file: test
Successfully processed 1 files; Failed processing 0 files
0
>>> os.stat('test')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
PermissionError: [WinError 5] Access is denied: 'test'
The problem is that it's mistakenly checking for ERROR_SHARING_VIOLATION
instead of ERROR_ACCESS_DENIED. Technically, getting a sharing violation should
be impossible here. That only applies to requesting execute (traverse), read
(list), write (add file), append (add subdirectory), or delete access for the
contents of the file or directory, not its metadata.
After modifying the code to instead check for ERROR_ACCESS_DENIED, os.stat
correctly falls back on using the file attributes from the WIN32_FIND_DATA:
>>> os.stat('test')
os.stat_result(st_mode=16895, st_ino=0, st_dev=0, st_nlink=0,
st_uid=0, st_gid=0, st_size=0, st_atime=1473589600,
st_mtime=1473589600, st_ctime=1473589600)
----------
nosy: +eryksun
title: py35 os.stat behavoir different than python 2.7 -> os.stat fails when
access is denied
versions: +Python 3.6
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Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue28075>
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