RFR: 8277489: Rewrite JAAS UnixLoginModule with FFM [v2]

[Shawn M Emery]

On Mon, 22 Dec 2025 14:42:42 GMT, Weijun Wang <weijun at openjdk.org> wrote:

>> Not generated.
>
> Thanks for the comments. I've pushed a new commit that removes all jextract-generated code and go fully manual. Is this better?
> 
> BTW, I haven't studied the use of `errorno` yet. Also, I have a TODO item at the beginning of `UnixLoginModule::login`. Please tell me your opinion on my concern.

Looks better, thank you.
Re: check for window platform earlier - yes, I think that this would be appropriate, but I haven't worked through how this would fallback to the existing windows implementation.
Re: other unix platforms - if FFM sysconf is implemented then allocation would not be left to chance on these systems.  Regarding the pwd structure - I would be very surprised if the core attributes would be any different.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28931#discussion_r2642289186