Issue #13772: In os.symlink() under Windows, do not try to guess the link

target's type (file or directory).  The detection was buggy and made the
call non-atomic (therefore prone to race conditions).
This commit is contained in:
Antoine Pitrou 2012-01-24 09:05:18 +01:00
commit 91ecea24f5
4 changed files with 14 additions and 19 deletions

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@ -2085,11 +2085,9 @@ Files and Directories
*target_is_directory*, which defaults to ``False``.
On Windows, a symlink represents a file or a directory, and does not morph to
the target dynamically. For this reason, when creating a symlink on Windows,
if the target is not already present, the symlink will default to being a
file symlink. If *target_is_directory* is set to ``True``, the symlink will
be created as a directory symlink. This parameter is ignored if the target
exists (and the symlink is created with the same type as the target).
the target dynamically. If *target_is_directory* is set to ``True``, the
symlink will be created as a directory symlink, otherwise as a file symlink
(the default).
Symbolic link support was introduced in Windows 6.0 (Vista). :func:`symlink`
will raise a :exc:`NotImplementedError` on Windows versions earlier than 6.0.
@ -2102,7 +2100,6 @@ Files and Directories
administrator level. Either obtaining the privilege or running your
application as an administrator are ways to successfully create symlinks.
:exc:`OSError` is raised when the function is called by an unprivileged
user.

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@ -500,7 +500,12 @@ class WalkTests(unittest.TestCase):
f.write("I'm " + path + " and proud of it. Blame test_os.\n")
f.close()
if support.can_symlink():
os.symlink(os.path.abspath(t2_path), link_path)
if os.name == 'nt':
def symlink_to_dir(src, dest):
os.symlink(src, dest, True)
else:
symlink_to_dir = os.symlink
symlink_to_dir(os.path.abspath(t2_path), link_path)
sub2_tree = (sub2_path, ["link"], ["tmp3"])
else:
sub2_tree = (sub2_path, [], ["tmp3"])
@ -1131,7 +1136,7 @@ class Win32SymlinkTests(unittest.TestCase):
os.remove(self.missing_link)
def test_directory_link(self):
os.symlink(self.dirlink_target, self.dirlink)
os.symlink(self.dirlink_target, self.dirlink, True)
self.assertTrue(os.path.exists(self.dirlink))
self.assertTrue(os.path.isdir(self.dirlink))
self.assertTrue(os.path.islink(self.dirlink))

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@ -458,6 +458,10 @@ Core and Builtins
Library
-------
- Issue #13772: In os.symlink() under Windows, do not try to guess the link
target's type (file or directory). The detection was buggy and made the
call non-atomic (therefore prone to race conditions).
- Issue #6631: Disallow relative file paths in urllib urlopen methods.
- Issue #13722: Avoid silencing ImportErrors when initializing the codecs

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@ -6551,7 +6551,6 @@ win_symlink(PyObject *self, PyObject *args, PyObject *kwargs)
wchar_t *wsrc, *wdest;
int target_is_directory = 0;
DWORD res;
WIN32_FILE_ATTRIBUTE_DATA src_info;
if (!check_CreateSymbolicLinkW())
{
@ -6581,16 +6580,6 @@ win_symlink(PyObject *self, PyObject *args, PyObject *kwargs)
if (wsrc == NULL)
goto error;
/* if src is a directory, ensure target_is_directory==1 */
if(
GetFileAttributesExW(
wsrc, GetFileExInfoStandard, &src_info
))
{
target_is_directory = target_is_directory ||
(src_info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY);
}
Py_BEGIN_ALLOW_THREADS
res = Py_CreateSymbolicLinkW(wdest, wsrc, target_is_directory);
Py_END_ALLOW_THREADS