On Fri, 6 Oct 2023 at 19:21, Amir Goldstein <amir73il@xxxxxxxxx> wrote:
>
> On Fri, Oct 6, 2023 at 7:42 PM Ryan Hendrickson
> > And there is the escaping that needs to happen for ':' and '\' when
> > parsing the path parameters (':' is only special syntax in lowerdir, but
> > the escaping logic seems to apply to upperdir and workdir as well, based
> > on my testing). Even using the new API, this is handled in the kernel.
> > We'd like to know if this escaping can be considered stable as well, and I
> > don't think that's a question for the libmount maintainer.
>
> Agree.
> Unlike the comma separated parameters list,
> upperdir,workdir,lowerdir are overlayfs specific format.
>
> ovl_unescape() (for upperdir/workdir) unescapes '\' characters.
> as does ovl_parse_param_split_lowerdirs().
> Not sure why this was needed for upperdir/workdir, but it It has
> been this way for a long time.
> I see no reason for it to change in the future.
Unescaping upperdir/workdir was the side effect of using a common
helper; it wasn't intentional, I think. The problem is that
unescaping breaks code that doesn't expect it, and filenames with
backslashes (and especially \\ or \: sequences) are very rare, so this
won't show up in testing.
At this point I'm not sure which is more likely to cause bugs: getting
rid of unescaping or leaving it alone.
One way out of this mess is to create explicit _unesc versions of these options.
Thanks,
Miklos
