On 24/03/2017 12:09, Andrew Dinn wrote:
:
I am unclear as to why you say there was never an intention to 'use the
attach API from regular applications or libraries'. Perhaps this was
just a bad design decision in the way VirtualMachine.attach or the
native code which underpins it was crafted. It's fairly clear that
having implemented this API in Java it would be open for use to load
into the current VM as well as into a foreign VM and it's hard top see
how the Genie is not out of the bottle by that point. You could, for
example, try to plug the gap by refusing to load an agent when the
target JVM is the requesting JVM. Of course, you could still then suffer
from cyclical loads via one or more intermediate JVMs so I don't think
that tactic constitutes a full remedy.
It was designed as an API for tools, that is why it was in tools.jar and
not the runtime/JRE. Tools or applications with tools.jar on the class
path could use it to load agents into the current running VM, that has
always been possible. It's futile (as I said) to try to prevent this on
the API side, it can only be disabled on the VM side.
-Alan.
