chroot to build an embedded filesystem?

zephyr1256

I'm working on an embedded project, and I need to compile much of my filesystem for it with optimizations to reduce size and for a different architecture. I thought portage would be useful for this, I could just build the filesystem, and then hand pick the config files, binaries, and library files I need from this system to stick into a compressed file system. I thought I might make a directory for this, and extract a stage 3 tarball in the directory, to get the base filesystem, do a gentoo install, possibly skipping kernel compile, and emerging only the packages I need. Of course this would have more stuff than I really need, so after it is done, I would grab I needed to put in compressed filesystems to go on some floppies. I want to do this because I don't really want to rebuild my whole system to a lower common denominator in terms of architecture, and I don't have a free partition to install such a system anyway(well I could wipe my NTFS drive, which I never use except as storage for mp3s and the like, but I'd have to do a fair bit to back all that up.). I might do a kernel for it as well, but as I already have a bootdisk, I'm not sure yet if it will be needed.

So would this idea work? Any danger of messing my system(assuming I correctly chroot and env-update before starting to emerge stuff)?
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Pythonhead · Posted: Fri Jun 06, 2003 7:04 pm Post subject:

This sounds plausible to me. I had a functioning Red Hat system where I installed Gentoo using that method. I was running KDE and slowly but surely had Gentoo compiling away in a chroot environment. Worked like a charm.

dol-sen · Posted: Sat Jun 07, 2003 7:30 am Post subject:

I did that to make my gentoo firewall system on my new machine since the firewall will have minimal hard drive space (read not enough to install gentoo with). It works much faster that way. I just created its own directory (/home/firewall) and created a script to automate the chroot process. I do it in a su'd terminal window

aja · Posted: Sat Jun 07, 2003 7:43 am Post subject:

Are you sure you want to use Gentoo for an embedded device? It's a bit heavy for that application - I'd normally used a tuned-for-embedding kernel like ucLinux -> and I'm not sure what you get by chroot'ing - you wouldn't be able to run any programs (or a kernel) compiled for a different architecture, and compiling to support both architectures would defeat the purpose. I can't see it would be any less work than using a development directory and alien toolchain. Generally, embedded systems have very few applications installed -> why portage (particularly since the sources for many packages in portage won't work on alternate architectures) and not simply make files for code that is specifiec to your embedded architecture?

zephyr1256 · Posted: Sat Jun 07, 2003 1:58 pm Post subject:

guy · Apprentice Joined: 31 Mar 2003 Posts: 286 Location: USA

Why chroot and not just do something like ROOT="firewalldir" emerge stuff ?
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