RFR: 8304438: jcmd JVMTI.agent_load should obey EnableDynamicAgentLoading [v6]

[Alex Menkov]

On Fri, 2 Jun 2023 03:44:48 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> The VM option EnableDynamicAgentLoading was added in JDK 9, default true, to allow deployment to choose whether to allow agents to be loaded/started in the VM. The VM option does the right thing for tools using the Attach API but jcmd JVMTI.agent_load was missed. This should be fixed to disallow loading JVMTI agents when the EnableDynamicAgentLoading is false.
>> 
>> The CSR is:
>> [JDK-8309250](https://bugs.openjdk.org/browse/JDK-8309250): jcmd JVMTI.agent_load should obey EnableDynamicAgentLoading
>> 
>> Testing:
>>  - run new test `test/jdk/sun/tools/jcmd/TestJcmdNoAgentLoad.java`
>>  - TBD: submit mach5 tiers 1-5 to make sure no new regressions are introduced
>
> Serguei Spitsyn has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains six additional commits since the last revision:
> 
>  - Merge
>  - review: use output.shouldHaveExitValue(0) in the test
>  - review: use output.shouldContain()
>  - move check for EnableDynamicAgentLoading to invoke_Agent_OnAttach
>  - minor renaming in new test TestJcmdNoAgentLoad.java
>  - 8304438: jcmd JVMTI.agent_load should obey EnableDynamicAgentLoading

test/jdk/sun/tools/jcmd/TestJcmdNoAgentLoad.java line 42:

> 40:  * @library /test/lib
> 41:  *
> 42:  * @run main/othervm -XX:-EnableDynamicAgentLoading TestJcmdNoAgentLoad

The test verifies only one scenario. I think we need to test 3 scenarios:
- -XX:-EnableDynamicAgentLoading
- +XX:-EnableDynamicAgentLoading
- default (no EnableDynamicAgentLoading arg)

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PR Review Comment: https://git.openjdk.org/jdk/pull/14244#discussion_r1214741247