RFR: 8277489: Rewrite JAAS UnixLoginModule with FFM

[Weijun Wang]

On Mon, 22 Dec 2025 07:19:11 GMT, Shawn M Emery <duke at openjdk.org> wrote:

>> Rewrite the native calls with FFM.
>
> src/jdk.security.auth/share/classes/com/sun/security/auth/module/UnixSystem.java line 67:
> 
>> 65:             }
>> 66: 
>> 67:             var gs = scope.allocate(gid_t, groupnum);
> 
> Should this be the size of gid_t * groupnum as the first argument and the byte alignment as the second?

This is `MemorySegment allocate(MemoryLayout elementLayout, long count)` in `SegmentAllocator.java`.

> src/jdk.security.auth/share/classes/com/sun/security/auth/module/UnixSystem.java line 70:
> 
>> 68:             groupnum = getgroups(groupnum, gs);
>> 69:             if (groupnum == -1) {
>> 70:                 throw new RuntimeException("getgroups returns " + groupnum);
> 
> Not a must-have, but would be nice to have a FFM for `errno` to provide better diagnostics.

Yes.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28931#discussion_r2639978799
PR Review Comment: https://git.openjdk.org/jdk/pull/28931#discussion_r2639979845