Re: [PATCH 02/18] mingw: implement `stat()` with symlink support

> From: Karsten Blees <blees@dcon.de>
> 
> With respect to symlinks, the current `mingw_stat()` implementation is
> almost identical to `mingw_lstat()`: except for the file type (`st_mode
> & S_IFMT`), it returns information about the link rather than the target.
> 
> Implement `mingw_stat()` by opening the file handle requesting minimal
> permissions, and then calling `GetFileInformationByHandle()` on it. This
> way, all links are resolved by the Windows file system layer.
> 
> If symlinks are disabled, use `mingw_lstat()` as before, but fail with
> `ELOOP` if a symlink would have to be resolved.

> 
> Signed-off-by: Karsten Blees <blees@dcon.de>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>  compat/mingw.c | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/compat/mingw.c b/compat/mingw.c
> index f5a0fe3325..59afd69686 100644
> --- a/compat/mingw.c
> +++ b/compat/mingw.c
> @@ -1026,9 +1026,26 @@ int mingw_lstat(const char *file_name, struct stat *buf)
>  {
>  	return do_lstat(0, file_name, buf);
>  }
> +
>  int mingw_stat(const char *file_name, struct stat *buf)
>  {
> -	return do_lstat(1, file_name, buf);
> +	wchar_t wfile_name[MAX_PATH];
> +	HANDLE hnd;
> +	int result;
> +
> +	/* open the file and let Windows resolve the links */
> +	if (xutftowcs_path(wfile_name, file_name) < 0)
> +		return -1;
> +	hnd = CreateFileW(wfile_name, 0,
> +			FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
> +			OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
> +	if (hnd == INVALID_HANDLE_VALUE) {
> +		errno = err_win_to_posix(GetLastError());
> +		return -1;
> +	}
> +	result = get_file_info_by_handle(hnd, buf);
> +	CloseHandle(hnd);
> +	return result;
>  }
>  
>  int mingw_fstat(int fd, struct stat *buf)