What does the 32-bit chroot actually do?[solved]

XenoTerraCide · Veteran Joined: 18 Jan 2004 Posts: 1418 Location: MI, USA

K here's the long and the short of ME. I've been running a 32-bit Gentoo system on an athlon-XP desktop for a while. I just bought an amd athlon 64 laptop. I'm planning on running a native 64 system. at least for now. I think I may need to do this 32-bit chroot thing at some point. I have how-to. but I'm not sure I understand exactly what I'm doing and what the implications of doing it is. I do understand what it's for. oh and say I want to install openoffice. is openoffice-bin a precompiled binary? and can someone point me to somewhere where I can learn to compile a 32bit firefox on this, sorry it's a lot of stuff I have to learn that I haven't yet. and I'd like a fully working system. so any other tips would help too.

Headrush · Posted: Sun Nov 27, 2005 7:43 pm Post subject:

There are no side effects of using a 32bit chroot.

Basically all a chroot is, is a new / location. Using that feature, we can make new directories that hold 32 bit binaries, libraries, etc.
Once in the chroot, the system cannot see directories outside of the chroot.
When in the 32bit chroot, you don't have to do anything special to compile 32 bit apps. If you follow the instructions/tutorials, your /etc/make.conf in the chroot will have applicable settings for a 32 bit CPU. You just emerge as normal.

Compiling any of the -bin packages, (firefox, openoffice), in a 32bit chroot is useless. Since the 64bit environment can run 32 bit binaries, you can run then there and they are the exact same. If you want to compile either of those from source, then you would have to do it in the 32 bit chroot.

I've found that with firefox-bin, openoffice-bin, and mplayer-bin, I don't have a need for a chroot anymore and have recently removed them.

xanas3712 · Guru Joined: 15 Oct 2004 Posts: 455

openoffice-bin is the binary. I would suggest just downloading firefox to get the 32 bit version rather than compiling it. It works fine that way and I can't see that any performance benefit in firefox is really gained from self compiling anyway. I'm using 64 bit 1.07 but downloaded the 32 bit rc2 of Firefox 1.5. It works well.

I had some problems with the 64 bit install a year ago and so started with a 32 bit install myself, which I'm not using at all now except as a chroot environment. It works very well for what you need it for. It basically will run applications requring x86-32 assembly (like emulators) and other such things.

I use a little script that does the following to get into my chroot environment

#!/bin/sh
mount -o bind /proc /mnt/gen32/proc
mount -o bind /dev /mnt/gen32/dev
mount -o bind /home /mnt/gen32/home
mount -o bind /mnt/cdrom /mnt/gen32/mnt/cdrom
mount -o bind /tmp /mnt/gen32/tmp
mount -o bind /boot /mnt/gen32/boot
mount -o bind / /mnt/gen32/mnt/gen64
xhost local:localhost
linux32 chroot /mnt/gen32 /bin/bash

XenoTerraCide · Veteran Joined: 18 Jan 2004 Posts: 1418 Location: MI, USA

ah ok. I guess the Open Office question really should be what's the difference between emerging openoffice and emerging openoffice-bin.

Headrush · Posted: Sun Nov 27, 2005 8:14 pm Post subject:

XenoTerraCide · Veteran Joined: 18 Jan 2004 Posts: 1418 Location: MI, USA

K thx.

fidel · Guru Joined: 16 Jul 2004 Posts: 407 Location: CH

Hi there! I am very new to chroot!... I found out that I am not able to linux32 chroot without root permissions... Therefore I always do:

whig · l33t Joined: 27 Nov 2004 Posts: 973 Location: New Zealand

I use sudo to let my user account access the 32 bit chroot. In one way this launches tabby (a program I wrote) and I can spawn all the 32 bit apps I like. For a look see http://www.rillion.net/tabby/index.html

whig · l33t Joined: 27 Nov 2004 Posts: 973 Location: New Zealand

PS here's a line from my /etc/sudoers

Headrush · Posted: Wed Nov 30, 2005 4:50 am Post subject:

Or use dchroot to all non-root users in a chroot.

You'll have to unmask it as it is ~x86 and ~amd64 but worked great when I used a 32 bit chroot.
I was even able to make menu entries and icons to start programs in the 32 bit chroot using dchroot. (no command line typing needed)

fidel · Guru Joined: 16 Jul 2004 Posts: 407 Location: CH

Thanks a lot! Great thing!.. just, dumb me doesn't really understand how to use dchroot.. :oops:

..
Since I want to chroot into a 32bit environment, how can I achieve to linux32 dchroot /gentoo32 /bin/bash..?? With this command I get:

fidel · Guru Joined: 16 Jul 2004 Posts: 407 Location: CH

really sorry to ask again!... I just don't get it to work! With tabby I see myself confronted with the same issues as before. I cannot have one command run an app in my 32bit chroot: If I want to add a new app in tabby, I need the same command line option to add an app... I need to change into my 32bit chroot first and can run a program THEN. I cannot enter a command line and let the program start from that command line...
Hard to explain!... well this doesn't work:

fidel · Guru Joined: 16 Jul 2004 Posts: 407 Location: CH

Dumb stupid me!... :oops:

sorry! of course I need to run tabby in my 32bit chroot environment!... :oops:

hmmmm!!... Really nice tool! Helps a lot! And really easy to configure!.. Concerning not needing to run chroot as root, I give up! Sad but oh well, I can live with chmod me:users every newly created file and so on.
Just wondering:

Headrush · Posted: Wed Nov 30, 2005 4:44 pm Post subject:

fidel · Guru Joined: 16 Jul 2004 Posts: 407 Location: CH

GREAT!!! THANKS!!!!

(...really didn't see this thread!... )

bakaohki · Posted: Sat Aug 19, 2006 8:38 pm Post subject:

I made a modified do_chroot.sh file, so one can use "./" in the parameters. It might be a bit complicated since I'm new to sed and friends...