RFR: JDK-8147388: Add diagnostic commands to attach JVMTI agent.

[Dmitry Samersoff]

Yasumasa,

diagnosticCommand.cpp:294

1. It's better to check _libpath.value() and write a message, that the
parameter is required.

2.  It might be better to avoid malloc here by pre-calcualting length of
required option length and than declare

char *new_options[new_options_len];

Otherwise looks good for me (I'll sponsor the push).

-Dmitry


On 2016-01-14 17:00, Yasumasa Suenaga wrote:
> Hi all,
> 
> We can use Attach API to attach JVMTI agent to live process.
> However, we have to write Java code for it.
> 
> If we can attach JVMTI agents through jcmd, it is very useful.
> So I want to add two new diagnostic commands:
> 
>  * JVMTI.agent_load: Load JVMTI native agent.
>  * JVMTI.javaagent_load: Load JVMTI java agent.
> 
> I maintain two JVMTI agents - HeapStats [1] and JLivePatcher [2].
> [1] is native agent, [2] is java agent.
> They provide a program for attaching to live process.
> 
> I guess that various JVMTI agents provide own attach mechanism like them.
> I think that we should provide general way to attach.
> 
> I've uploaded webrev. Could you review it?
>   http://cr.openjdk.java.net/~ysuenaga/JDK-8147388/webrev.00/
> 
> I'm jdk9 committer, however I cannot access JPRT.
> So I need a sponsor.
> 
> 
> Thanks,
> 
> Yasumasa
> 
> 
> [1] http://icedtea.classpath.org/wiki/HeapStats
> [2] https://github.com/YaSuenag/jlivepatcher  (in Japanese)
> 


-- 
Dmitry Samersoff
Oracle Java development team, Saint Petersburg, Russia
* I would love to change the world, but they won't give me the sources.