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Date: Tue, 21 Feb 2012 11:34:28 +0000
Message-ID: <CADSoG1vOz3agNFs2dG_u4D-Kw4PBv+YHdJUE_ziSUOCaqdo35g@mail.gmail.com>
Subject: Re: shared_info::init_obcaseinsensitive implemented incorrectly
From: Nick Lowe <nick DOT lowe AT gmail DOT com>
To: cygwin AT cygwin DOT com
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I really should subscribe to get individual messages and not just the
digest so that I can reply properly. Sorry!

> Just call NtOpenDirectoryObject on \\SYSTEMROOT, rather than NtOpenSymbolicLinkObject.

I would have thought that NtOpenSymbolicLinkObject would have been the
more correct approach as the object expected is a symbolic link. No?

>That's not an off-chance.  It works for all admin accounts.

Hmm, strange. Unless the query (0x1) symbolic link specific access
right is specified, I always get STATUS_ACCESS_DENIED. With it
specified, it succeeds as an administrator or fails otherwise.
(I have only tested this under 64-bit Windows 7.)

Regards,

Nick

On Tue, Feb 21, 2012 at 10:26 AM, Nick Lowe <nick DOT lowe AT gmail DOT com> wrote:
> I have just tested this and it works. It is faster, simpler and has
> less overheads than querying the registry for a potentially stale
> value.
>
> Just call NtOpenSymbolicLinkObject for \SYSTEMROOT with a
> DesiredAccess of 0 and no attributes flags in the OBJECT_ATTRIBUTES
> structure.
>
> This will fail with STATUS_ACCESS_DENIED if the system is running with
> case insensitivity and STATUS_OBJECT_NAME_NOT_FOUND if running with
> case sensitivity.
>
> For correctness, on the off chance that a successful NTSTATUS value is
> returned, the system is running with case insensitivity and the handle
> must be closed.
>
> Regards,
>
> Nick
>
> On Tue, Feb 21, 2012 at 9:52 AM, Nick Lowe <nick DOT lowe AT gmail DOT com> wrote:
>> OK, fair enough, it is an edge case... I am a stickler for correctness! :P
>>
>> Looking at previous threads though actually, I notice that the
>> following is documented by Microsoft regarding the obcaseinsensitive
>> value:
>>
>> "If this setting is enabled, case insensitivity is enforced for all
>> directory objects, symbolic links, and IO objects, including file
>> objects. Disabling this setting does not allow the Win32 subsystem to
>> become case sensitive."
>>
>> You could just get away with therefore, in theory, a call to
>> NtOpenSymbolicLinkObject for \SYSTEMROOT. If it fails because it
>> cannot be found, you know that the system is running with case
>> sensitivity, otherwise, it is case sensitive.
>>
>> Regards,
>>
>> Nick

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