diff options
| -rw-r--r-- | Lib/test/test_os.py | 43 | ||||
| -rw-r--r-- | Misc/ACKS | 1 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Windows/2022-03-13-20-35-41.bpo-46785.Pnknyl.rst | 1 | ||||
| -rw-r--r-- | Modules/posixmodule.c | 12 |
4 files changed, 56 insertions, 1 deletions
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py index 7f7d14e..1243b57 100644 --- a/Lib/test/test_os.py +++ b/Lib/test/test_os.py @@ -23,6 +23,7 @@ import subprocess import sys import sysconfig import tempfile +import textwrap import threading import time import types @@ -2859,6 +2860,48 @@ class Win32NtTests(unittest.TestCase): self.assertEqual(0, handle_delta) + def test_stat_unlink_race(self): + # bpo-46785: the implementation of os.stat() falls back to reading + # the parent directory if CreateFileW() fails with a permission + # error. If reading the parent directory fails because the file or + # directory are subsequently unlinked, or because the volume or + # share are no longer available, then the original permission error + # should not be restored. + filename = os_helper.TESTFN + self.addCleanup(os_helper.unlink, filename) + deadline = time.time() + 5 + command = textwrap.dedent("""\ + import os + import sys + import time + + filename = sys.argv[1] + deadline = float(sys.argv[2]) + + while time.time() < deadline: + try: + with open(filename, "w") as f: + pass + except OSError: + pass + try: + os.remove(filename) + except OSError: + pass + """) + + with subprocess.Popen([sys.executable, '-c', command, filename, str(deadline)]) as proc: + while time.time() < deadline: + try: + os.stat(filename) + except FileNotFoundError as e: + assert e.winerror == 2 # ERROR_FILE_NOT_FOUND + try: + proc.wait(1) + except subprocess.TimeoutExpired: + proc.terminate() + + @os_helper.skip_unless_symlink class NonLocalSymlinkTests(unittest.TestCase): @@ -1694,6 +1694,7 @@ Anthony Starks David Steele Oliver Steele Greg Stein +Itai Steinherz Marek Stepniowski Baruch Sterin Chris Stern diff --git a/Misc/NEWS.d/next/Windows/2022-03-13-20-35-41.bpo-46785.Pnknyl.rst b/Misc/NEWS.d/next/Windows/2022-03-13-20-35-41.bpo-46785.Pnknyl.rst new file mode 100644 index 0000000..0a87abd --- /dev/null +++ b/Misc/NEWS.d/next/Windows/2022-03-13-20-35-41.bpo-46785.Pnknyl.rst @@ -0,0 +1 @@ +Fix race condition between :func:`os.stat` and unlinking a file on Windows, by using errors codes returned by ``FindFirstFileW()`` when appropriate in ``win32_xstat_impl``. diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c index 03de470..26c8e7b 100644 --- a/Modules/posixmodule.c +++ b/Modules/posixmodule.c @@ -1905,7 +1905,17 @@ win32_xstat_impl(const wchar_t *path, struct _Py_stat_struct *result, /* Try reading the parent directory. */ if (!attributes_from_dir(path, &fileInfo, &tagInfo.ReparseTag)) { /* Cannot read the parent directory. */ - SetLastError(error); + switch (GetLastError()) { + case ERROR_FILE_NOT_FOUND: /* File cannot be found */ + case ERROR_PATH_NOT_FOUND: /* File parent directory cannot be found */ + case ERROR_NOT_READY: /* Drive exists but unavailable */ + case ERROR_BAD_NET_NAME: /* Remote drive unavailable */ + break; + /* Restore the error from CreateFileW(). */ + default: + SetLastError(error); + } + return -1; } if (fileInfo.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) { |