On Wed, 21 Feb 2024 21:16:46 GMT, Alex Menkov <amen...@openjdk.org> wrote:
>> VirtualMachine.loadAgentPath/loadAgentLibrary can fail with
>> AgentLoadException in 2 cases:
>> - attach listener returns error; in the case the exception is thrown from
>> HotSpotVirtualMachine.processCompletionStatus (called from
>> HotSpotVirtualMachine.execute);
>> - attach listener returns success, but reply does not contain Agent_onAttach
>> return code ("return code: %d" message).
>>
>> before jdk21 if attach listener fails to load required library, it returned
>> error (case 1)
>> from jdk21 attach listener always returns success (case 2)
>> Both cases are ok, but for 2nd case HotSpotVirtualMachine.loadAgentLibrary
>> read only single line of the response message, so exception message didn't
>> contain error details.
>>
>> The fix updates HotSpotVirtualMachine.loadAgentLibrary to read the whole
>> response message.
>> Walking through the code, fixed some other minor things in attach listener
>> and attach API implementation (commented in the code)
>>
>> Testing:
>> - test/jdk/com/sun/tools;
>> - tier1,tier2,tier5-svc
>
> src/hotspot/share/prims/jvmtiAgentList.cpp line 201:
>
>> 199:
>> 200: // Invokes Agent_OnAttach for agents loaded dynamically during runtime.
>> 201: jint JvmtiAgentList::load_agent(const char* agent_name, const char*
>> absParam,
>
> The method never returns error, dropped value return type
only 1 caller (load_agent() from attachListener) extract `absParam` from attach
command, other pass constants ("true" or "false")
Moved conversion from string to bool there.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/17954#discussion_r1498327164
