bhyve: monitor: detect monitor exitHEADmain

Currently, sending SIGTERM to the bhyve process triggers ACPI poweroff
for a VM. However, when running bhyve in monitor mode (-M), there are
two processes: the monitor process and the actual VM process. Sending
SIGTERM to the VM process works as before -- it powers off the VM.
But sending SIGTERM to the monitor process just kills the monitor
process, leaving the stale VM process running.

Fix that by creating a pipe between these two processes. The child
process uses the pipe to detect when the monitor goes away, and exits
automatically.

MFC after:		2 weeks
Reviewed by:		markj
Sponsored by:		The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D58788

0 files changed, 0 insertions, 0 deletions