GeezerVison is showing github.com — gh-82367: Use `FindFirstFile` Win32 API in `ntpath.realpath()` by moonsikpark · Pull Request #110298 · python/cpython
gh-82367: Use FindFirstFile Win32 API in ntpath.realpath()
#110298
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@@ -377,7 +377,8 @@ the :mod:`glob` module.)
Return the canonical path of the specified filename, eliminating any symbolic
links encountered in the path (if they are supported by the operating
system).
system). On Windows, this function will also resolve MS-DOS (also called 8.3)
style names such as ``C:\\PROGRA~1`` to ``C:\\Program Files``.
If a path doesn't exist or a symlink loop is encountered, and *strict* is
``True``, :exc:`OSError` is raised. If *strict* is ``False``, the path is
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@@ -97,6 +97,9 @@ Other Language Changes
if supported.
(Contributed by Victor Stinner in :gh:`109649`.)
* :func:`os.path.realpath` now resolves MS-DOS style file names even if
the file is not accessible.
(Contributed by Moonsik Park in :gh:`82367`.)
New Modules
===========
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@@ -23,7 +23,6 @@
import genericpath
from genericpath import *
__all__ = ["normcase","isabs","join","splitdrive","splitroot","split","splitext",
"basename","dirname","commonprefix","getsize","getmtime",
"getatime","getctime", "islink","exists","lexists","isdir","isfile",
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@@ -601,7 +600,7 @@ def abspath(path):
return _abspath_fallback(path)
try:
from nt import _getfinalpathname, readlink as _nt_readlink
from nt import _findfirstfile, _getfinalpathname, readlink as _nt_readlink
except ImportError:
# realpath is a no-op on systems without _getfinalpathname support.
realpath = abspath
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@@ -688,10 +687,15 @@ def _getfinalpathname_nonstrict(path):
except OSError:
# If we fail to readlink(), let's keep traversing
pass
path, name = split(path)
# TODO (bpo-38186): Request the real file name from the directory
# entry using FindFirstFileW. For now, we will return the path
# as best we have it
# If we get these errors, try to get the real name of the file without accessing it.
if ex.winerror in (1, 5, 32, 50, 87, 1920, 1921):
try:
name = _findfirstfile(path)
path, _ = split(path)
except OSError:
path, name = split(path)
else:
path, name = split(path)
if path and not name:
return path + tail
tail = join(name, tail) if tail else name
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@@ -2,6 +2,7 @@
import ntpath
import os
import string
import subprocess
import sys
import unittest
import warnings
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@@ -637,6 +638,48 @@ def test_realpath_cwd(self):
with os_helper.change_cwd(test_dir_short):
self.assertPathEqual(test_file_long, ntpath.realpath("file.txt"))
@unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname')
def test_realpath_permission(self):
# Test whether python can resolve the real filename of a
# shortened file name even if it does not have permission to access it.
ABSTFN = ntpath.realpath(os_helper.TESTFN)
os_helper.unlink(ABSTFN)
os_helper.rmtree(ABSTFN)
os.mkdir(ABSTFN)
self.addCleanup(os_helper.rmtree, ABSTFN)
test_file = ntpath.join(ABSTFN, "LongFileName123.txt")
test_file_short = ntpath.join(ABSTFN, "LONGFI~1.TXT")
with open(test_file, "wb") as f:
f.write(b"content")
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# Automatic generation of short names may be disabled on
# NTFS volumes for the sake of performance.
# They're not supported at all on ReFS and exFAT.
subprocess.run(
# Try to set the short name manually.
['fsutil.exe', 'file', 'setShortName', test_file, 'LONGFI~1.TXT'],
creationflags=subprocess.DETACHED_PROCESS
)
try:
self.assertPathEqual(test_file, ntpath.realpath(test_file_short))
except AssertionError:
raise unittest.SkipTest('the filesystem seems to lack support for short filenames')
# Deny the right to [S]YNCHRONIZE on the file to
# force nt._getfinalpathname to fail with ERROR_ACCESS_DENIED.
p = subprocess.run(
['icacls.exe', test_file, '/deny', '*S-1-5-32-545:(S)'],
creationflags=subprocess.DETACHED_PROCESS
)
if p.returncode:
raise unittest.SkipTest('failed to deny access to the test file')
self.assertPathEqual(test_file, ntpath.realpath(test_file_short))
def test_expandvars(self):
with os_helper.EnvironmentVarGuard() as env:
env.clear()
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1 change: 1 addition & 0 deletions
1
Misc/ACKS
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@@ -1373,6 +1373,7 @@ Peter Parente
Alexandre Parenteau
Dan Parisien
HyeSoo Park
Moonsik Park
William Park
Claude Paroz
Heikki Partanen
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@@ -0,0 +1,2 @@
:func:`os.path.realpath` now resolves MS-DOS style file names even if
the file is not accessible. Patch by Moonsik Park.
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@@ -4809,6 +4809,37 @@ os__getfinalpathname_impl(PyObject *module, path_t *path)
return result;
}
/*[clinic input]
os._findfirstfile
path: path_t
/
A function to get the real file name without accessing the file in Windows.
[clinic start generated code]*/
static PyObject *
os__findfirstfile_impl(PyObject *module, path_t *path)
/*[clinic end generated code: output=106dd3f0779c83dd input=0734dff70f60e1a8]*/
{
PyObject *result;
HANDLE hFindFile;
WIN32_FIND_DATAW wFileData;
WCHAR *wRealFileName;
Py_BEGIN_ALLOW_THREADS
hFindFile = FindFirstFileW(path->wide, &wFileData);
Py_END_ALLOW_THREADS
if (hFindFile == INVALID_HANDLE_VALUE) {
path_error(path);
return NULL;
}
wRealFileName = wFileData.cFileName;
result = PyUnicode_FromWideChar(wRealFileName, wcslen(wRealFileName));
FindClose(hFindFile);
return result;
}
/*[clinic input]
os._getvolumepathname
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@@ -15961,6 +15992,7 @@ static PyMethodDef posix_methods[] = {
OS__GETFULLPATHNAME_METHODDEF
OS__GETDISKUSAGE_METHODDEF
OS__GETFINALPATHNAME_METHODDEF
OS__FINDFIRSTFILE_METHODDEF
OS__GETVOLUMEPATHNAME_METHODDEF
OS__PATH_SPLITROOT_METHODDEF
OS__PATH_NORMPATH_METHODDEF
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