bug#63245: Potential regression: cp --preserve=mode or --preserve=all fails to copy files from subdirectory

[Schlomo Schapiro]

Hi Pádraig,

Wow, nice! That was really quick!

how would this patch get into the affected distros as a bugfix? Then it
would actually help me as I can't ship a patched coreutils with ReaR.

Kind regards,
Schlomo

On Wed, 3 May 2023 at 18:40, Pádraig Brady <P@draigbrady.com> wrote:

> On 03/05/2023 10:27, Schlomo Schapiro wrote:
> > Hello,
> >
> > I'm a maintainer of the Relax-and-Recover (
> https://relax-and-recover.org/)
> > Open Source project and think that I might have found a major regression
> in
> > cp, starting somewhere with version 9.
> >
> > Please see
> https://bugs.launchpad.net/ubuntu/+source/coreutils/+bug/2017414
> > and https://github.com/rear/rear/issues/2972 for how I found out about
> this.
> >
> > Problem:
> >
> > We use a cp call like the following to copy various files and directory
> > into a destination path with preserving the structure:
> >
> > cp --verbose -t DESTINATION -L --preserve=all --parents SOURCE...
> >
> > Over the last 10+ years that worked well on all Linux distros (ReaR is
> > build for and tested on nearly all distros), but I recently found out
> that
> > on Ubuntu 23.04 this fails like this:
> >
> > # rm -Rf /tmp/f && mkdir /tmp/f && cp --verbose -t /tmp/f -L
> --preserve=all
> > --parents /etc/apt/sources.list && echo yes ; ls -lR
> > /tmp/f/etc/apt/sources.list
> > /etc/apt/sources.list
> > /etc -> /tmp/f/etc
> > /etc/apt -> /tmp/f/etc/apt
> > '/etc/apt/sources.list' -> '/tmp/f/etc/apt/sources.list'
> > cp: ‘etc/apt’: No such file or directory
> > -rw-r--r-- 1 root root 2437 Apr 23 09:53 /etc/apt/sources.list
> > -rw-r--r-- 1 root root 2437 Apr 23 09:53 /tmp/f/etc/apt/sources.list
> > #
> >
> > Ubuntu 23.04 uses cp (GNU coreutils) 9.1
> >
> > On Ubuntu 22.04 there is cp (GNU coreutils) 8.32 and the same example
> works
> > as expected:
> >
> > # rm -Rf /tmp/f && mkdir /tmp/f && cp --verbose -t /tmp/f -L
> --preserve=all
> > --parents /etc/apt/sources.list && echo yes ; ls -lR
> > /tmp/f/etc/apt/sources.list /etc/apt/sources.list
> > /etc -> /tmp/f/etc
> > /etc/apt -> /tmp/f/etc/apt
> > '/etc/apt/sources.list' -> '/tmp/f/etc/apt/sources.list'
> > yes
> > -rw-r--r-- 1 root root 263 Mär 26 15:20 /etc/apt/sources.list
> > -rw-r--r-- 1 root root 263 Mär 26 15:20 /tmp/f/etc/apt/sources.list
> > #
> >
> > BTW, I checked also on many other distros that ReaR supports and all
> > distros with cp version 9.1 fail in the same way.
> >
> > Can you please have a look and advise how to proceed? We at the ReaR
> > project can of course change our code to use tar for example, but I won't
> > be surprised if other users will also meet this changed behaviour and
> maybe
> > it is indeed a bug.
>
> Looks like a bug indeed.
> The attached patch should address this in coreutils.
> Any deployments of coreutils 9.1-9.3 inclusive would need to apply this.
>
> thanks,
> Pádraig
>