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

[Roger Riggs]

On Wed, 23 Nov 2022 08:38:02 GMT, Chris Hegarty <chegar at openjdk.org> wrote:

>> This commit guards thread modifications for the process reaper thread with doPrivileged.
>
> 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.

-------------

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