[buildd-tools-devel] Bug#679499: Bug#679499: Bug#679499: schroot: suspend fails from chroot

[Roger Leigh]

On Mon, Oct 15, 2012 at 12:16:16AM +0100, Roger Leigh wrote:
> This is quite an interesting problem, and will need a bit more
> investigation before I find a solution.
> 
> bash sets up its own process group on startup.  When you call
> "suspend", it signals the whole process group to stop.  But since
> schroot isn't in the same group, it's not suspended.  Ideally,
> you would only run a login shell with schroot, but we're not in
> an ideal world ;)

Just as another datapoint:
Try running

  ssh localhost -t bash

and then try suspend in the shell.  You'll notice that it behaves
identically to schroot.  The -t is to allocate a TTY, otherwise
you don't get any shell job control (or suspend).

It would be interesting to know how any other similar tools
behave.  su/sudo/chroot just exec their command after setting
things up, so there isn't a parent process waiting for a child.
So it's limited to programs which fork a shell and wait for it,
like schroot and ssh.


Regards,
Roger

-- 
  .''`.  Roger Leigh
 : :' :  Debian GNU/Linux    http://people.debian.org/~rleigh/
 `. `'   schroot and sbuild  http://alioth.debian.org/projects/buildd-tools
   `-    GPG Public Key      F33D 281D 470A B443 6756 147C 07B3 C8BC 4083 E800