Visible symlinks under Windows
jpeach at samba.org
Wed Feb 6 17:37:34 GMT 2008
On Feb 6, 2008, at 3:27 AM, Corinna Vinschen wrote:
> as Cygwin developer, it's sort of frustrating that there isn't a way
> identify symlinks on Samba shares from a Windows user space
> for what they really are.
> While most Windws applications have no idea how to handle symlinks,
> that's obviously not the case for a Linux emulator. However, right
> due to the fact that Cygwin has no idea how to create a symlink on a
> Samba share, it always creates fake symlinks on a Samba share which
> work in the Windws environment, and it only recognizes symlinks as
> or directories, depending on the target of the symlink.
The Apple and Linux SMB clients have a format of storing a symlink in
a file. If you used this format, then you would be able to
interoperate symlinks created by these clients.
see smbfs_windows_readlink() and smbfs_create_windows_symlink_data()
> If there would be a way to identify a symlink and to create real
> symlinks on a Samba share, Cygwin would happily handle them.
> So I'm wondering, is there any interest to implement another extension
> along the lines of the changes to the SMB_FS_OBJECTID_INFORMATION
> which would allow a "knowing" Win32 application to retrieve the actual
> symlink file information as well as allowing it to create real
> If so, the question is, how could that be done? I had the following
> We could fake an Extended Attribute which contain the symlink
> When requesting a symlink's file information, it could return an EA
> called, say, ".smb.symlink". The EA value consists of the relevant
> parts of the content of the stat buffer returned by lstat, plus the
> target path of the symlink in UNIX path notation.
> Creating a symlink could work by creating a simple file with an
> EA in the EA list, called, say, ".smb.symlink.create". The value is
> the target path in UNIX path notation. Given that ZwCreateFile (and
> SMB protocol counterpart) allows to define EAs at file creation time,
> creating a symlink would be a simple one step operation.
This is a nice idea.
The advantage of Minshall+French symlink format
- it is already supported by other SMB clients
- it doesn't require server changes
- it works on Windows and Samba volumes
The main disadvantage is that it doesn't address your goal of getting
resolving actual symlinks that are on the server.
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