The vm_extra_pre_umount function in vmimage.subr served two purposes:
It removed /etc/resolv.conf and /qemu (if cross-building), and it
provided a function for cloudware to override in order to make cloud
specific changes to the filesystem before constructing a disk image.
This resulted in a number of bugs:
1. When cross-building, the emulator binary was left as /qemu in the
Azure, GCE, Openstack and Vagrant images.
2. The build host's resolv.conf was left as /etc/resolv.conf in the
basic-ci and basic-cloudinit images.
3. When building GCE images, a Google-specific resolv.conf file was
constructed, and then deleted before the disk image was created.
Move the bits needed for running code inside a VM staging directory
from vm_install_base into a new vm_emulation_setup routine, and move
the corresponding cleanup bits from vm_extra_pre_umount to a new
vm_emulation_cleanup routine.
Remove the /qemu and /etc/resolv.conf cleanups from the cloudware
configuration files (where they exist) since we will now be running
vm_emulation_cleanup to remove those even when vm_extra_pre_umount
has been overridden.
Override vm_emulation_cleanup in gce.conf since in that one case (and
*only* that one case) we don't want to clean up resolv.conf (since it
was constructed for the VM image rather than copied from the host).
releng/14.1 candidate.
MFC after: 1 week
Sponsored by: https://www.patreon.com/cperciva
copied from the build host. It is renamed to /etc/resolv.conf.bak
on boot, so never used anyway.
Noticed by: peter
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
