Reporting broken symlinks to clients

[Jeremy Allison]

On Thu, Jun 13, 2013 at 04:22:38PM -0700, Christof Schmitt wrote:
> I got asked if it would make sense to report broken symlinks to
> Windows clients. With the current code, the stat() call in
> smbd_dirptr_lanman2_mode_fn fails on the broken symlink and it is not
> reported in the directory listing to the client. This could be changed
> without too much effort, like this hack:
> 
> --- a/source3/smbd/trans2.c
> +++ b/source3/smbd/trans2.c
> @@ -1553,11 +1553,22 @@ static bool
> smbd_dirptr_lanman2_mode_fn(TALLOC_CTX *ctx,
>                    SMB_VFS_STAT(state->conn, smb_fname) != 0) {
>                 /* Needed to show the msdfs symlinks as
>                  * directories */
> +               int stat_errno = errno;
>  
>                 ms_dfs_link = check_msdfs_link(state->conn,
>                                                smb_fname->base_name,
>                                                &smb_fname->st);
> -               if (!ms_dfs_link) {
> +               if (!ms_dfs_link && stat_errno == ENOENT) {
> +                       /* Invalid link target, try to get lstat() data to show
> +                        * a dummy file */
> +                       if (SMB_VFS_LSTAT(state->conn, smb_fname) != 0) {
> +                               DEBUG(5,("smbd_dirptr_lanman2_mode_fn: "
> +                                        "Couldn't stat and lstat [%s] (%s)\n",
> +                                        smb_fname_str_dbg(smb_fname),
> +                                        strerror(errno)));
> +                               return false;
> +                       }
> +               } else if (!ms_dfs_link) {
>                         DEBUG(5,("smbd_dirptr_lanman2_mode_fn: "
>                                  "Couldn't stat [%s] (%s)\n",
>                                  smb_fname_str_dbg(smb_fname),
> 
> This could be useful in environments where the same directory is
> accessible to Windows clients and to Linux/Unix systems. When a
> broken symlink is created, the Windows clients would at least be able
> to see that there is a file.
> 
> Comments?

What is the goal of presenting the broken links to the Windows clients ?

I'm trying to understand the use case here.

Thanks,

Jeremy.