RFR: 8319589: Attach from root to a user java process not supported in Mac [v3]

[Sergey Chernyshev]

On Tue, 23 Sep 2025 02:43:45 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Sergey Chernyshev has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Apply suggestions from code review
>>   
>>   Co-authored-by: David Holmes <62092539+dholmes-ora at users.noreply.github.com>
>
> src/jdk.attach/macosx/classes/sun/tools/attach/VirtualMachineImpl.java line 49:
> 
>> 47:     // the latter can be changed by the user.
>> 48:     // Any changes to this needs to be synchronized with HotSpot.
>> 49:     private static final String tmpdir;
> 
> So we can't cache this any more?

Thanks David for pointing this out. A different instance with a different PID may have a different temp path, so the path should be specific to the instance. Since we don't need the path outside the constructor, I think we don't need to cache it. On the other hand I see that `getTempDirFromPid` is called twice, once for `.java_pid` and another time in `createAttachFile` when `.java_pid` doesn't exist. Would you suggest storing the path in a local variable in the constructor and then concatenating it with attach file name, or would a non-static member variable be more suitable for this?

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PR Review Comment: https://git.openjdk.org/jdk/pull/25824#discussion_r2372940682