Re: [ros-svn] [hbirr] 17912: The share disposition isn't necessary for FILE_READ_ATTRIBUTES.

[Thomas Weidenmueller]

hbirr(a)svn.reactos.com wrote:
>   The share disposition isn't necessary for
> FILE_READ_ATTRIBUTES. 
Actually this prevents opening the file during the operation. A better
candidate for GetFileAttributesEx is NtQueryFullAttributesFile which
accepts a OBJECT_ATTRIBUTES structure instead of a handle, so there's no
need to even open the file at all.

Best Regards,

Thomas

[Hartmut Birr]

Thomas Weidenmueller wrote:

>  hbirr(a)svn.reactos.com wrote:
>   
>
> >  The share disposition isn't necessary for
> > FILE_READ_ATTRIBUTES.
> >     
> >  
> Actually this prevents opening the file during the operation. 
>  
Usually, it isn't possible. The share disposition is checked inside the
FSD with IoCheckShareAccess. IoCheckShareAccess can only return an
error, if one of  the attributes FILE_READ_DATA, FILE_EXECUTE,
FILE_WRITE_DATA, FILE_APPEND_DATA or DELETE is set and some other
conditions are TRUE. For the single attribute FILE_READ_ATTRIBUTES, the
share disposition has no effect and IoCheckShareAccess does always
return STATUS_SUCCESS.

>  A better
> candidate for GetFileAttributesEx is NtQueryFullAttributesFile 
>  
NtQueryFullAttributesFile does also set the share disposition, which isn't necessary.

- Hartmut