DataSourceSmartOS: add locking of serial device.

cloud-init and mdata-get each have their own implementation of the
SmartOS metadata protocol.  If cloud-init and other services that call
mdata-get are run concurrently, crosstalk on the serial port can cause
them both to become confused.

This change makes it so that cloud-init uses the same cooperative
locking scheme that's used by mdata-get, thus preventing cross-talk
between mdata-get and cloud-init.

For testing, a VM running on a SmartOS host and pyserial are required.
If the tests are run on a platform other than SmartOS, those that use a
real serial port are skipped.  pyserial remains commented in
requirements.txt because most testers will not be running atop SmartOS.

LP: #1746605

0 files changed, 0 insertions, 0 deletions