On 2021-12-05 04:54, Takashi Yano wrote:
On Tue, 30 Nov 2021 19:04:57 +0200
Oskar Skog wrote:
vboxsharedfs file systems no longer work. Any attempt to access will
result in "too many levels of symbolic links".
This only affects the VirtualBox shared folder, the Samba share works
just fine.
....
I tested with VirtualBox version 6.1.30.
In 64bit Windows10, for vbox shared path, GetFinalPathNameByHandleW()
returns path with trailing '\'. As a result, RtlEqualUnicodeString()
fails and tries to resolve symlink repeatedly.
For example, RtlEqualUnicodeString() compares \??\UNC\VBoxSrv\tmp and
\??\UNC\VBoxSrv\tmp\, then it fails.
This does not happen in 32bit Windows10. It seems that UNC path is not
treated as a symlink in 32bit Windows10. I am not sure why.
Therefore, I have applied a patch which stops to treat UNC path as a
symlink for testing as follows.
diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc
index baf04ce89..31a96ca58 100644
--- a/winsup/cygwin/path.cc
+++ b/winsup/cygwin/path.cc
@@ -3490,6 +3490,9 @@ restart:
ret = GetFinalPathNameByHandleW (h, fpbuf, NT_MAX_PATH, 0);
if (ret)
{
+ if (wcsstr (fpbuf, L"\\\\?\\UNC\\") == fpbuf)
+ goto file_not_symlink;
+
UNICODE_STRING fpath;
RtlInitCountedUnicodeString (&fpath, fpbuf, ret * sizeof (WCHAR));
I have confirmed this patch fixes the issue. In addition, this patch
also resolves the issue:
https://cygwin.com/pipermail/cygwin/2021-December/250103.html
Is this the right thing?
I have tested the patch and it is now possible to access /cygdrive/z
again.
But if I create a symlink on that filesystem, it's not identified as a
symlink. Although, I don't know if this has ever worked as it is the
first time I've ever tested it, it probably hasn't ever worked (see
below).
user@DESKTOP-******* /cygdrive/z$ ln -s report.pdf test.pdf
user@DESKTOP-******* /cygdrive/z$ ls -l report.pdf test.pdf
-rw-r--r-- 1 user None 1454562 Nov 28 12:05 report.pdf
-rw-r--r-- 1 user None 34 Dec 5 16:36 test.pdf
user@DESKTOP-******* /cygdrive/z$ cat test.pdf
!<symlink>▒▒report.pdfuser@DESKTOP-******* /cygdrive/z$
I think it's because "special" attributes don't work on VirtualBox
shared folders, I can't hide files in Explorer either.
So I don't think the patch has caused any regression here.
The samba share (Y:) works, just as it did before, symlinks work too.
(Sorry about the previous mail, I apparently suck at email.)
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