Re: [Qemu-devel] [PULL 00/24] Linux-user updates

[Joakim Tjernlund]

Peter Maydell <address@hidden> wrote on 2014/08/18 14:45:49:
> 
> On 18 August 2014 13:38, Joakim Tjernlund 
<address@hidden> wrote:
> > Peter Maydell <address@hidden> wrote on 2014/08/18 12:58:48:
> >> Well, binfmt-misc works fine for me as it is and presumably
> >> for most people or we'd have had more complaints. So
> >> breaking all those existing working setups is really something
> >> we should avoid as much as possible.
> >
> > How do you use it? With LXC booting a VM with traditional init?
> 
> No. Just a straightforward chroot environment with a
> statically linked qemu in it, and a binfmt_misc config like:
> 
> e104462:trusty:qemu$ cat /proc/sys/fs/binfmt_misc/qemu-arm
> enabled
> interpreter /usr/bin/qemu-arm-static

Where does -static come from? Is that the standard name a static qemu-user 
build gets?

> flags: OC
> offset 0
> magic 7f454c4601010100000000000000000002002800
> mask ffffffffffffff00fffffffffffffffffeffffff
> 
> This works fine for the things I try to run in the chroot
> (mostly test programs, also bash and basic command
> line utilities).

Using bash as a login shell one need one of(from bash man page):
 A  login shell is one whose first character of argument zero is a -, or
 one started with the --login option.

> 
> > There are complaints which dists had to solve because QEMU didn't. 
Usually
> > this is a separate static QEMU package/hack with a binfmt wrapper.
> > Gentoo used to have one but this got removed.
> 
> I'm sure there are cases which don't work; but we should try
> to find a way which allows us to make those work (with a
> recommended change to binfmt misc registration) which
> doesn't break the old configs in the process.

This was considered/discussed to some point and no-one could come up
with a better approach.

 Jocke