Re: Enquiry about building a new root file system

[Jean-Christian de Rivaz <jc@eclis.ch>]

Le 21. 08. 14 19:51, David Lechner a écrit :
> On 08/21/2014 09:50 AM, Jean-Christian de Rivaz wrote:
> > I just tested the first method on that page (Multistrap) and I 
> > suspect that the information need an update, because Lenny source 
> > don't exists anymore and Grip is now a dead end according to the 
> > EmDebian front page.
> > Generally, EmDebian is hard to follow because there is a lot of 
> > outdated information on the site and it's very difficult to sort 
> > between the obsolete/unusable and actual/tested information. I have 
> > read a lot of pages on the site and I am still lost on how is the 
> > best/recommended way to start a new cross embedded project based on 
> > Debian Jessie
> >
> > A possible way to improve the situation could be to define a popular 
> > use case, for example creating a complete armhf image on a amd64 host 
> > mixing standard package from the distribution and local package from 
> > cross-building, and to maintain a tested tutorial on how to do this 
> > from a clean system.
>
> I am working on a (just for fun) project to run jessie on the LEGO 
> MINDSTORMS EV3. We are using multistrap to create the root file 
> system. One of the most useful things I found was a script called 
> polystrap[1]. At that point in time, we were still using wheezy, but 
> have since move to jessie. We have evolved the polystrap script into a 
> tool we call brickstrap[2][3]. We've updated some stuff from polystrap 
> that is specific to jessie (like a new ssh host key type and systemd 
> stuff). Hopefully it is still extensible enough that it could be 
> useful to you. A couple of notes: we are using ubuntu trusty 64-bit 
> for our build system, however multistrap and libguesfs are both broken 
> at the moment, so we are hosting our own patched versions of these 
> tools. Also, you might check out josch's bootstrap.debian.net 
> project[4]. I don't know anything about it, but it is designed for 
> this sort of thing.
>
>
> [1]: 
> https://blog.mister-muffin.de/2014/01/11/why-do-i-need-superuser-privileges-when-i-just-want-to-write-to-a-regular-file/
> [2]: 
> https://github.com/ev3dev/ev3dev/wiki/Using-brickstrap-to-cross-compile-and-debug
> [3]: https://github.com/ev3dev/brickstrap
> [4]: https://blog.mister-muffin.de/category/debian/
Many thanks Davis for sharing all of this. I have found some of 
inspiring code in your work.

I am a bit confused about the call of all *.preinst scripts between the 
unpacking and the setting. As far as I understand the Debian Policy 
Manual, the *.preinst scripts are to be called before the unpacking, so 
this should be a task of multistrap but it don't seem to do that (at 
least in multistrap 2.1.20). Or maybe I misunderstand something.

I wonder why you don't use a local package to modify files like you 
wants. I suspect that this will simplify your tool and will allow 
modification on an upgrade of the system.

Anyway, brickstrap is very interesting to study a working example.