Gentoo Archives: gentoo-alt

From: Piergiorgio Beruto <piergiorgio.beruto@×××××.com>
To: gentoo-alt@l.g.o
Subject: Re: [gentoo-alt] prefixed gentoo for cross-compile (question)
Date: Wed, 27 Apr 2011 11:29:56
In Reply to: Re: [gentoo-alt] prefixed gentoo for cross-compile (question) by Michael Haubenwallner
Hello Michael,

2011/4/27 Michael Haubenwallner <haubi@g.o>:
> Hi Piergiorgio, > > On 04/26/11 18:10, Piergiorgio Beruto wrote: >> Hi, >> I'm an embedded sw developer already used to gentoo and portage. > > Is your gentoo and portage usage already related to your embedded development?
Actually yes, I've been using Gentoo for several years for a wide range of applications (both for my company and on my own) like routers, L2 switches, servers, multimedia and desktop applications. In fact I love gentoo because of its fexibility, like many other users :-) Embedded development used to be a different kind of beast, but at company level the requirements for "big" embedded projects are the same as for traditional development and I think it's the time to enhance our ways of working to speed up our daily work and meet the requirements. This is why I think portage might be a good solution: in embedded development we're really missing a build system which allows you to pick up traditional open source packages and your own packages maximizing code reuse among projects. I believe portage has the degree of modularity required, and since it's open source is much easier to learn and to maintain.
> >> I am wondering whether gentoo prefix could help me in the following: I >> would like to use portage to cross compile some base linux packages >> plus some board specific applications for a different number of boards >> each requiring their own patches and packages, with a huge amount of >> code to be shared among them. > > Basically yes, ... > >> I was lookong at crossdev but > > ... however I've not seen anyone trying to make crossdev working in Prefix. > > But I fail to see a reason for crossdev not to work in Prefix, even if > I've not used crossdev myself. So IMO it just has To Be Done (tm).
Well, I've tried to have crossdev itself working in prefix and I succeeded, the big problem was to cross-build the glibc, then I didnt have the time to finish but maybe I could use some help?
> >> the big problem is that I CAN'T get >> administrative priviledges on the development machine, in fact each >> user at the moment builds the packages in their own home. > > This is one of the reasons Gentoo Prefix was born. > >> To be more precise I wish I could use portage installed in my home >> directory and have it use some cross-toolchain (either pre-built or >> built through portage) to actually download, patch, configure, build >> and install packages to some directory which will eventually be turned >> into a target filesystem someway. >> I've tried to use crossdev inside prefixed gentoo but failed to have >> it working and I'm not sure it's the correct approach anyway. > > The special use case for Prefix here IMO is the combination of > ROOT="/somewhere" with EPREFIX="" and non-Prefix profiles/keywords.
Yes, crossdev already uses the ROOT variable to specify the installation path, I'm not yet very familiar with prefix related variables so it might only be a matter of studying... For instance what you mean exactly by "non-Prefix profiles/keywords"?
> >> Have you guys any suggestion about my problem? That would save a lot >> of users to keep developing new build systems and re-inventing the >> wheel each time! Also they would never come to something as good and >> featured as portage. > > For what I can say if I were in your situation: > > First, I'd try crossdev on some (virtualized) vanilla Gentoo Linux > system, to see if crossdev /is/ the tool doing what I need, and to > see how it works.
Yes, I'm already a crossdev user and I actually think it could be the tool I am looking for, possibly with some tweaks.
> > Then I'd try to fix crossdev to work within Gentoo Prefix, trying > to get identical output as on the vanilla Gentoo Linux system.
That's the difficult part :)
> > But I also would expect lots of work, resulting in patches for crossdev, > ebuilds/eclasses, as well as (prefix-)portage.
That's what I am NOT familiar with, I am an experienced portage user but not (yet) a good portage developer. Maybe I could use a little help with this? Do you guys find this kind of development useful/challenging? In which case, have you got a rough idea about the effort in making a working prototype (your guess would be much better then mine)? Oh, one last thing: one of the big issues is about host machines... it would be nice if the prefixed Gentoo could be portable across different development machines / users. Do you think it's possible to have a prefixed gentoo "relocatable"? I mean, I setup my prefixed system, then i "tar cvj" the entire system then untar for a different user / different machine, "change some config files / environment variables" and have my prefixed system work without bootstrapping again? Thank you very much for your time and help, Regards, Piergiorgio
> > HTH, > /haubi/ > -- > Michael Haubenwallner > Gentoo on a different level > >


Subject Author
Re: [gentoo-alt] prefixed gentoo for cross-compile (question) Michael Haubenwallner <haubi@g.o>
Re: [gentoo-alt] prefixed gentoo for cross-compile (question) Ramon van Alteren <ramon@××××××××××.nl>