Seeking developer to assist with adding OpenAFS Reparse Tag Support to Cygwin

[Corinna Vinschen]

On Feb 28 06:52, Jeffrey Altman wrote:
> On 2/28/2013 4:03 AM, Corinna Vinschen wrote:
> 
> > The core routine is symlink_info::check_reparse_point in path.cc.
> > 
> > Actually, Cygwin always opens files with FILE_OPEN_REPARSE_POINT
> > and then, if it *is* a reparse point, it reads the contents of the
> > reparse point and expects it to be of type IO_REPARSE_TAG_SYMLINK
> > or IO_REPARSE_TAG_MOUNT_POINT.  Those are handled as symlinks.
> > Other types are not recognized and the FILE_ATTRIBUTE_REPARSE_POINT
> > attribute is deleted from the DOS attributes.  The later file open
> > call in fhandler.cc will omit the FILE_OPEN_REPARSE_POINT flag from
> > the open flags, so it will open the file transparently via the
> > reparse redirector.
> > 
> > But there's a chance that this doesn't happen in all circumstances as
> > expected.  As a first cut, look for usage of FILE_OPEN_REPARSE_POINT and
> > the usage of the path_conv::is_rep_symlink method thoughout fhandler*.cc
> > and syscalls.cc.
> 
> Thank you Corinna.
> 
> In my initial e-mail I pointed to an MSDN document which describes the
> inconsistent behavior of the Win32 API with regards to reparse points.
> The key thing to take away from that is that regardless of what the
> application (in this case Cygwin) wants, FILE_OPEN_REPARSE_POINT will be
> included in the underlying CreateFile() call for operations such
> as
> 
>   GetFileAttributes[Ex]
>   GetFileSecurity
>   Directory enumeration

Did you look into the code?  Cygwin doesn't use WIn32 functions to
access the file system.  It uses the underlying native NT functions.

> but Cygwin lists it as:
> 
>   -rwxr-xr-x 1 jaltman None       63 Nov  1 01:27 ti.exe
> 
> where 63 bytes is the size of the reparse point data not the target.  If
> Cygwin is going to discard FILE_ATTRIBUTE_REPARSE_POINT, then it must
> also resolve the target attributes when collecting stat info.

http://cygwin.com/acronyms/#PTC


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat