RFR: 8229957: Harden pid verification in attach mechanism

[Severin Gehwolf]

On Tue, 2019-08-20 at 16:32 -0700, Leonid Mesnik wrote:
> Hi
> 
> Could you review following fix which add sanity check of pid value in 
> attach mechanism on *nix based platforms.
> 
> PID for java process is always positive on affected OS. Hotspot 
> internally uses signal (SIGQUIT) while attaching. So using negative 
> numbers as pid might cause very unexpected results and should be prevented.
> 
> webrev: http://cr.openjdk.java.net/~lmesnik/8229957/webrev.00/

This looks OK to me.

Thanks,
Severin