[sugar] Bitfrost compliance for Update.1

[Albert Cahalan]

Ivan Krstic writes:
> On Nov 2, 2007, at 12:02 PM, Michael Stone wrote:
>>> Can we create subdirectories within /tmp?
>>
>> I would really prefer it if you used $SUGAR_ACTIVITY_ROOT/tmp instead.
>
> I think Erik was in fact referring to the 'tmp' inside
> SUGAR_ACTIVITY_ROOT. Writes to the real /tmp are non-compliant
> and will fail.

This is a defect in the spec.

You can bind-mount right over top of /tmp, and also over
top of /var/tmp. You can split the namespace. You have
everything needed to do a per-activity private /tmp.

Having /tmp work like /tmp is one less obstacle to getting
things ported.

Remember that /var/tmp is preserved across reboots.
It lets apps recover from crashes and power loss.