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Compatibility improvements to reparse point handling.

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This commit is contained in:
Joe_Lowe
2017-06-14 13:01:28 -07:00
committed by Corinna Vinschen
parent ec86124748
commit 7a4e299a18
3 changed files with 87 additions and 36 deletions
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63
winsup/cygwin/fhandler_disk_file.cc
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@ -161,15 +161,19 @@ path_conv::isgood_inode (ino_t ino) const
return true;
}
/* Check reparse point for type. IO_REPARSE_TAG_MOUNT_POINT types are
either volume mount points, which are treated as directories, or they
are directory mount points, which are treated as symlinks.
IO_REPARSE_TAG_SYMLINK types are always symlinks. We don't know
anything about other reparse points, so they are treated as unknown. */
static inline uint8_t
readdir_check_reparse_point (POBJECT_ATTRIBUTES attr)
/* Check reparse point to determine if it should be treated as a posix symlink
or as a normal file/directory. Mount points are treated as normal directories
to match behavior of other systems. Unknown reparse tags are used for
things other than links (HSM, compression, dedup), and generally should be
treated as a normal file/directory. Native symlinks and mount points are
treated as posix symlinks, depending on the prefix of the target name.
This logic needs to agree with equivalent logic in path.cc
symlink_info::check_reparse_point() .
*/
static inline bool
readdir_check_reparse_point (POBJECT_ATTRIBUTES attr, bool remote)
{
uint8_t ret = DT_UNKNOWN;
bool ret = false;
IO_STATUS_BLOCK io;
HANDLE reph;
UNICODE_STRING subst;
@ -185,20 +189,29 @@ readdir_check_reparse_point (POBJECT_ATTRIBUTES attr)
&io, FSCTL_GET_REPARSE_POINT, NULL, 0,
(LPVOID) rp, MAXIMUM_REPARSE_DATA_BUFFER_SIZE)))
{
if (rp->ReparseTag == IO_REPARSE_TAG_MOUNT_POINT)
if (!remote && rp->ReparseTag == IO_REPARSE_TAG_MOUNT_POINT)
{
RtlInitCountedUnicodeString (&subst,
(WCHAR *)((char *)rp->MountPointReparseBuffer.PathBuffer
+ rp->MountPointReparseBuffer.SubstituteNameOffset),
rp->MountPointReparseBuffer.SubstituteNameLength);
/* Only volume mountpoints are treated as directories. */
if (RtlEqualUnicodePathPrefix (&subst, &ro_u_volume, TRUE))
ret = DT_DIR;
else
ret = DT_LNK;
if (check_reparse_point_target (&subst))
ret = true;
}
else if (rp->ReparseTag == IO_REPARSE_TAG_SYMLINK)
ret = DT_LNK;
{
if (rp->SymbolicLinkReparseBuffer.Flags & SYMLINK_FLAG_RELATIVE)
ret = true;
else
{
RtlInitCountedUnicodeString (&subst,
(WCHAR *)((char *)rp->SymbolicLinkReparseBuffer.PathBuffer
+ rp->SymbolicLinkReparseBuffer.SubstituteNameOffset),
rp->SymbolicLinkReparseBuffer.SubstituteNameLength);
if (check_reparse_point_target (&subst))
ret = true;
}
}
NtClose (reph);
}
}
@ -1995,8 +2008,7 @@ fhandler_disk_file::readdir_helper (DIR *dir, dirent *de, DWORD w32_err,
/* Set d_type if type can be determined from file attributes. For .lnk
symlinks, d_type will be reset below. Reparse points can be NTFS
symlinks, even if they have the FILE_ATTRIBUTE_DIRECTORY flag set. */
if (attr &&
!(attr & (~FILE_ATTRIBUTE_VALID_FLAGS | FILE_ATTRIBUTE_REPARSE_POINT)))
if (attr && !(attr & ~FILE_ATTRIBUTE_VALID_FLAGS))
{
if (attr & FILE_ATTRIBUTE_DIRECTORY)
de->d_type = DT_DIR;
@ -2005,19 +2017,22 @@ fhandler_disk_file::readdir_helper (DIR *dir, dirent *de, DWORD w32_err,
de->d_type = DT_REG;
}
/* Check for directory reparse point. These may be treated as a posix
symlink, or as mount point, so need to figure out whether to return
a directory or link type. In all cases, returning the INO of the
reparse point (not of the target) matches behavior of posix systems.
/* Check for reparse points that can be treated as posix symlinks.
Mountpoints and unknown or unhandled reparse points will be treated
as normal file/directory/unknown. In all cases, returning the INO of
the reparse point (not of the target) matches behavior of posix systems.
*/
if ((attr & (FILE_ATTRIBUTE_DIRECTORY | FILE_ATTRIBUTE_REPARSE_POINT))
== (FILE_ATTRIBUTE_DIRECTORY | FILE_ATTRIBUTE_REPARSE_POINT))
if (attr & FILE_ATTRIBUTE_REPARSE_POINT)
{
OBJECT_ATTRIBUTES oattr;
InitializeObjectAttributes (&oattr, fname, pc.objcaseinsensitive (),
get_handle (), NULL);
de->d_type = readdir_check_reparse_point (&oattr);
/* FUTURE: Ideally would know at this point if reparse point
is stored on a remote volume. Without this, may return DT_LNK
for remote names that end up lstat-ing as a normal directory. */
if (readdir_check_reparse_point (&oattr, false/*remote*/))
de->d_type = DT_LNK;
}
/* Check for Windows shortcut. If it's a Cygwin or U/WIN symlink, drop the