[lug] Strange Ideas for Cross-Platform/Cross-Distribution Development

[Michael J. Hammel]

Buildroot does this by having host-tools for managing the target
rootfs.  You could probably build your own toolset and point them at
the target rootfs.  You may not even need chroot to do this, depending
on the tools.  In this scenario the Ubuntu rootfs is just a directory
tree managed by the host-tools.  You don't actually run anything in it.

Which tools you build/use depends on what you're trying to do.  I
imagine all that dpkg stuff, which Fedora has but I don't know how full
featured they are.

On Tue, 2018-06-12 at 19:09 +0000, stimits at comcast.net wrote:
> Hi,
>  
> This is more or less just for fun, but could end up being quite
> valuable. I am looking at an image of an Ubuntu file system in a
> subdirectory of a Fedora 27 installation. Not only is this root file
> system Ubuntu instead of Fedora, it is also 64-bit ARM (and the
> Fedora holding it is x86_64). I have a number of cross-compile tools,
> and typically this Ubuntu file system gets edited and then flashed to
> an embedded system.
>  
> The strangeness comes because I was thinking how cool it would be to
> chroot to that alternate root file system and to use "apt" and family
> (e.g., "apt-get") within that alternate root file system
> independently of what is on my Fedora host. Fedora actually has some
> cross-ubuntu apt tools, but they are designed to be some sort of
> bridge between RPM format and DEB format packages. I don't want to do
> that...I want this chroot to be purely within the alternate
> directory.
>  
> If I just chroot (or "systemd-nspawn") nothing will work at all
> because everything there is arm64. However, I suppose it might be
> possible to place the x86_64 versions of apt and apt-get and dpkg
> within that directory tree and use those while pretending arm64 is a
> foreign architecture. Has anyone here heard of any kind of HOWTO for
> this? Or perhaps suggestions on which Ubuntu packages I might have to
> copy from an Ubuntu x86_64 system to make this work chroot?
>  
> Thanks!
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