Questions about com.sun.tools.attach implementation on windows

[Staffan Larsen]

Another suggestion for alternative implementation is to use window’s named pipes.

/Staffan

On 10 okt 2014, at 12:54, Thomas Stüfe <thomas.stuefe at gmail.com> wrote:

> Thanks for answering and clarifying the history! 
> 
> It seems after reading up on it, that kernel32.dll has a fixed base address and therefore is always loaded to the same base, system wide. If that is true, at least handing over addresses to GetProcAddress() etc from injector to target VM should always work.
> 
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> On Thu, Oct 9, 2014 at 2:19 PM, Alan Bateman <Alan.Bateman at oracle.com> wrote:
> On 09/10/2014 02:17, Thomas Stüfe wrote:
> 
> :
> 
> I would love to know why we do it this way. I am sure there is a valid reason for it. Maybe Backward compatibility?
> 
> This was a very typical way for debugging utilities to work at the time. It was never intended of course to be used to attach to non-HotSpot VMs and also pre-dates a lot of the security protections and other features that were subsequently introduced. One thing to know is there wasn't a strict requirement to be able to attach to JDKs running previous releases so if a new underlying mechanism is introduced then it shouldn't be a major compatibility issue. Also as the attach API is pluggable then it would be possible to have both old and new providers for a time for cases where it was really necessary to attach to older releases.
> 
> -Alan
> 

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