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

[David Holmes]

On Tue, 23 Sep 2025 16:57:34 GMT, Sergey Chernyshev <schernyshev at openjdk.org> wrote:

>> 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?

I would save it in a local in the constructor and pass it to `createAttachFile` rather than passing the pid.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25824#discussion_r2373540696