bpo-37834: Normalise handling of reparse points on Windows (GH-15231)

bpo-37834: Normalise handling of reparse points on Windows
* ntpath.realpath() and nt.stat() will traverse all supported reparse points (previously was mixed)
* nt.lstat() will let the OS traverse reparse points that are not name surrogates (previously would not traverse any reparse point)
* nt.[l]stat() will only set S_IFLNK for symlinks (previous behaviour)
* nt.readlink() will read destinations for symlinks and junction points only

bpo-1311: os.path.exists('nul') now returns True on Windows
* nt.stat('nul').st_mode is now S_IFCHR (previously was an error)
This commit is contained in:
Steve Dower 2019-08-21 15:27:33 -07:00 committed by GitHub
parent bcc446f525
commit df2d4a6f3d
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16 changed files with 477 additions and 240 deletions

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@ -878,7 +878,12 @@ _Py_attribute_data_to_stat(BY_HANDLE_FILE_INFORMATION *info, ULONG reparse_tag,
FILE_TIME_to_time_t_nsec(&info->ftLastAccessTime, &result->st_atime, &result->st_atime_nsec);
result->st_nlink = info->nNumberOfLinks;
result->st_ino = (((uint64_t)info->nFileIndexHigh) << 32) + info->nFileIndexLow;
if (reparse_tag == IO_REPARSE_TAG_SYMLINK) {
/* bpo-37834: Only actual symlinks set the S_IFLNK flag. But lstat() will
open other name surrogate reparse points without traversing them. To
detect/handle these, check st_file_attributes and st_reparse_tag. */
result->st_reparse_tag = reparse_tag;
if (info->dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT &&
reparse_tag == IO_REPARSE_TAG_SYMLINK) {
/* first clear the S_IFMT bits */
result->st_mode ^= (result->st_mode & S_IFMT);
/* now set the bits that make this a symlink */