[Python-checkins] bpo-37412: Fix os.getcwd() for long path on Windows (GH-14424) (GH-14451)
Victor Stinner
webhook-mailer at python.org
Fri Jun 28 12:23:11 EDT 2019
https://github.com/python/cpython/commit/68c1c398f3534af16309a86ab815b61d2487e6db
commit: 68c1c398f3534af16309a86ab815b61d2487e6db
branch: 3.8
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: Victor Stinner <vstinner at redhat.com>
date: 2019-06-28T18:23:06+02:00
summary:
bpo-37412: Fix os.getcwd() for long path on Windows (GH-14424) (GH-14451)
* Fix test for integer overflow.
* Add an unit test.
(cherry picked from commit ec3e20a2d1edddb0558f9d32e2b367904ccdde88)
Co-authored-by: Victor Stinner <vstinner at redhat.com>
files:
M Lib/test/test_os.py
M Modules/posixmodule.c
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index 18cd78b55f60..2e73906f93c3 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -22,6 +22,7 @@
import subprocess
import sys
import sysconfig
+import tempfile
import threading
import time
import unittest
@@ -87,6 +88,60 @@ def test_getcwd(self):
cwd = os.getcwd()
self.assertIsInstance(cwd, str)
+ def test_getcwd_long_path(self):
+ # bpo-37412: On Linux, PATH_MAX is usually around 4096 bytes. On
+ # Windows, MAX_PATH is defined as 260 characters, but Windows supports
+ # longer path if longer paths support is enabled. Internally, the os
+ # module uses MAXPATHLEN which is at least 1024.
+ #
+ # Use a directory name of 200 characters to fit into Windows MAX_PATH
+ # limit.
+ #
+ # On Windows, the test can stop when trying to create a path longer
+ # than MAX_PATH if long paths support is disabled:
+ # see RtlAreLongPathsEnabled().
+ min_len = 2000 # characters
+ dirlen = 200 # characters
+ dirname = 'python_test_dir_'
+ dirname = dirname + ('a' * (dirlen - len(dirname)))
+
+ with tempfile.TemporaryDirectory() as tmpdir:
+ with support.change_cwd(tmpdir):
+ path = tmpdir
+ expected = path
+
+ while True:
+ cwd = os.getcwd()
+ self.assertEqual(cwd, expected)
+
+ need = min_len - (len(cwd) + len(os.path.sep))
+ if need <= 0:
+ break
+ if len(dirname) > need and need > 0:
+ dirname = dirname[:need]
+
+ path = os.path.join(path, dirname)
+ try:
+ os.mkdir(path)
+ # On Windows, chdir() can fail
+ # even if mkdir() succeeded
+ os.chdir(path)
+ except FileNotFoundError:
+ # On Windows, catch ERROR_PATH_NOT_FOUND (3) and
+ # ERROR_FILENAME_EXCED_RANGE (206) errors
+ # ("The filename or extension is too long")
+ break
+ except OSError as exc:
+ if exc.errno == errno.ENAMETOOLONG:
+ break
+ else:
+ raise
+
+ expected = path
+
+ if support.verbose:
+ print(f"Tested current directory length: {len(cwd)}")
+
def test_getcwdb(self):
cwd = os.getcwdb()
self.assertIsInstance(cwd, bytes)
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 4301e876c7ce..bceee89917cb 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -3333,7 +3333,7 @@ posix_getcwd(int use_bytes)
terminating \0. If the buffer is too small, len includes
the space needed for the terminator. */
if (len >= Py_ARRAY_LENGTH(wbuf)) {
- if (len >= PY_SSIZE_T_MAX / sizeof(wchar_t)) {
+ if (len <= PY_SSIZE_T_MAX / sizeof(wchar_t)) {
wbuf2 = PyMem_RawMalloc(len * sizeof(wchar_t));
}
else {
More information about the Python-checkins
mailing list