[maemo-developers] New developer - lots of questions

[From: Igor Stoppa]

On Fri, 2007-11-16 at 15:11 -0500, ext maemo at bitblit.net wrote:
> On Fri, 16 Nov 2007, Igor Stoppa wrote:
> 
> > If disk space is not an issue for you
> 
> Nope, it isn't...
> 
> > , maybe you can do like me and use
> > a chrooted environment for each sdk (i use it because I have a full
> > 64bit system, but scratchbox is only 32 bit). I prefer this solution
> > since it makes it quite easy to experiment: install your chrooted
> > system, make a copy of it and feel free to trash it after experimenting.
> 
> My development is also pure 64bit :-)
> 
> So, do you install a 32bit distro + scratchbox inside the chroot or just 
> scratchbox? I already have a 32bit chroot installed already (mainly to run 
> 32bit plugins and codecs).
> 
> > The gotcha is that I have to do all the bindmounting that scratchbox
> > would do from the outside. Apparently doing a double bindmount from
> > chroot to sbox of a /dev or /proc directory doesn't work and at the
> > second step you end up with an empty directory.
> 
> Could you explain this a bit more?

ok,

*I have the chroot environment in /var/chroot/maemo : you can follow the
instructions from the official debian howto; i use sid

*I have inside the main directory of my user, a directory for the same
user to be bindmounted in the chrooted
environment: /home/igor/maemo_home_igor

*Inside that I have also a directory that is used as home for the
scratchbox user: /home/igor/maemo_home_igor/sbox_home

here is the relevant part of my fstab:

# maemo chroot
/sys    /var/chroot/maemo/sys  none bind      0       0
/tmp    /var/chroot/maemo/tmp  none bind      0       0
/dev    /var/chroot/maemo/dev  none bind      0       0      0       0
/dev/pts    /var/chroot/maemo/dev/pts  none bind      0       0
/dev/shm    /var/chroot/maemo/dev/shm  none bind      0       0
/proc   /var/chroot/maemo/proc none bind      0       0
/proc/sys/fs/binfmt_misc   /var/chroot/maemo/proc/sys/fs/binfmt_misc
none bind      0       0
/home/igor/maemo_home_igor /var/chroot/maemo/home/igor none bind     0
0
/home/igor/maemo_home_igor/sbox_home /var/chroot/maemo/scratchbox/users/igor/home/igor none bind    0    0
/var/chroot/maemo/scratchbox /var/chroot/maemo/scratchbox/users/igor/scratchbox none bind    0    0
/tmp /var/chroot/maemo/scratchbox/users/igor/tmp none bind    0    0
/proc /var/chroot/maemo/scratchbox/users/igor/proc none bind    0    0
/proc/sys/fs/binfmt_misc   /var/chroot/maemo/scratchbox/users/igor/proc/sys/fs/binfmt_misc none bind      0       0
/dev /var/chroot/maemo/scratchbox/users/igor/dev none bind    0    0
/dev/pts /var/chroot/maemo/scratchbox/users/igor/dev/pts none bind    0
0
/dev/shm /var/chroot/maemo/scratchbox/users/igor/dev/shm none bind    0
0
/sys /var/chroot/maemo/scratchbox/users/igor/sys none bind    0    0




I use this script to start everything:

#!/bin/bash
mount /var/chroot/maemo/sys
mount /var/chroot/maemo/tmp
mount /var/chroot/maemo/dev
mount /var/chroot/maemo/dev/pts
mount /var/chroot/maemo/dev/shm
mount /var/chroot/maemo/proc
mount /var/chroot/maemo/proc/sys/fs/binfmt_misc
mount /var/chroot/maemo/home/igor
mount /var/chroot/maemo/scratchbox/users/igor/home/igor
mount /var/chroot/maemo/scratchbox/users/igor/scratchbox
mount /var/chroot/maemo/scratchbox/users/igor/tmp
mount /var/chroot/maemo/scratchbox/users/igor/proc
mount /var/chroot/maemo/scratchbox/users/igor/proc/sys/fs/binfmt_misc
mount /var/chroot/maemo/scratchbox/users/igor/dev
mount /var/chroot/maemo/scratchbox/users/igor/dev/pts
mount /var/chroot/maemo/scratchbox/users/igor/dev/shm
mount /var/chroot/maemo/scratchbox/users/igor/sys

chroot /var/chroot/maemo /sb_run

umount /var/chroot/maemo/scratchbox/users/igor/sys
umount /var/chroot/maemo/scratchbox/users/igor/dev/shm
umount /var/chroot/maemo/scratchbox/users/igor/dev/pts
umount /var/chroot/maemo/scratchbox/users/igor/dev
umount /var/chroot/maemo/scratchbox/users/igor/proc/sys/fs/binfmt_misc
umount /var/chroot/maemo/scratchbox/users/igor/proc
umount /var/chroot/maemo/scratchbox/users/igor/tmp
umount /var/chroot/maemo/scratchbox/users/igor/scratchbox
umount /var/chroot/maemo/scratchbox/users/igor/home/igor
umount /var/chroot/maemo/home/igor
umount /var/chroot/maemo/proc/sys/fs/binfmt_misc
umount /var/chroot/maemo/proc
umount /var/chroot/maemo/dev/shm
umount /var/chroot/maemo/dev/pts
umount /var/chroot/maemo/dev
umount /var/chroot/maemo/tmp
umount /var/chroot/maemo/sys




*the sb_run script that is executed in the previous script lives
in /var/chroot/maemo and is the following:

#!/bin/bash
/scratchbox/sbin/register_misc_runner
sux - igor scratchbox
/scratchbox/sbin/register_misc_runner -d



Not exactly straightforward, but as I said I had some problem with
cascaded bindmounting and this in the end works for me; furthermore it
keeps the user data safe by removing all the bindomounts as soon as you
log out from scratchbox. As a nice sideeffect, the sbox daemon gets
killed as soon as you log out from the chroot. The combined effect of
these 2 features makes it safe to discard your scratchbox installation
without having to worry about wiping out data from your main user
directory.


However it was my first attempt at using scratchbox so maybe there are
simpler ways to achieve what i wanted.

-- 
Cheers, Igor

Igor Stoppa <igor.stoppa at nokia.com>
(Nokia Multimedia - CP - OSSO / Helsinki, Finland)