Re: [PATCH 2/4] Add functions get_relative_cwd() and is_inside_dir()

> The function get_relative_cwd() works just as getcwd(), only that it
> takes an absolute path as additional parameter, returning the prefix
> of the current working directory relative to the given path.  If the
> cwd is no subdirectory of the given path, it returns NULL.
> ...
> +/*
> + * get_relative_cwd() gets the prefix of the current working directory
> + * relative to 'dir'.  If we are not inside 'dir', it returns NULL.
> + * As a convenience, it also returns NULL if 'dir' is already NULL.
> + */
> +char *get_relative_cwd(char *buffer, int size, const char *dir)
> +{
> +	char *cwd = buffer;
> +
> +	if (!dir || !getcwd(buffer, size))
> +		return NULL;