RFR: 8297451: ProcessHandleImpl should assert privilege when modifying reaper thread

[Chris Hegarty]

On Wed, 23 Nov 2022 15:22:47 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> src/java.base/share/classes/jdk/internal/misc/InnocuousThread.java line 137:
>> 
>>> 135:     public static Thread newSystemThread(String name, Runnable target,
>>> 136:                                          long stackSize, int priority,
>>> 137:                                          boolean daemon) {
>> 
>> Thanks for adding this overload, I think that it will be useful for the future too.   ( it never seems to matter how many variants of these factories we have, we still need one more :-) )
>
> I would prefer to to avoid creating new factories when the desired function can be done on the resulting thread.
> Such as `setDaemon()` and `setName()`, etc.
> It does avoid the doPriv in this case, but is not necessary and when the security manager goes away, will leave around clutter (duplicated) functionality.

Looking beyond this specific change, there is a lot of potential use for this new factory elsewhere in the code. It also avoids similar bugs from possibly reoccurring (by having the setDaemon call inside the factory).

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PR: https://git.openjdk.org/jdk/pull/11309