When using "sh << EOF", what is between this line and EOF runs
with no attached terminal. But we need a terminal for running the
build. So we have to use "sh -c ". But then nesting of double
quotes, $, etc is too complicated. So run as root, and become back
user only when exec'ing. For some reason $@ does not work, so use
a variable set to $@.
Still WIP but some progress...
When moving a shell to a cgroup not associated with a session,
then subsequent calls to pam_systemd or pam_elogind create
a new session, and a new cgroup for that session, so that the
cgroup of the calling process is not used (this is a problem
with both systemd and elogind). For systemd, the problem can be
solved by passing --slice <user slice> to systemd-run. For elogind,
we need to first move the shell to a non session cgroup, then run
sudo so that a new session is created, then pass the cpuset to that
session's cgroup. Hopefully, if neither systemd nor elgind is used,
then the former solution should work (to be tested!!!).