RFR: 8277489: Rewrite JAAS UnixLoginModule with FFM [v10]

[Weijun Wang]

On Wed, 21 Jan 2026 21:01:30 GMT, Weijun Wang <weijun at openjdk.org> wrote:

>> src/jdk.security.auth/share/classes/com/sun/security/auth/module/UnixSystem.java line 118:
>> 
>>> 116:             = LINKER.downcallHandle(SYMBOL_LOOKUP.findOrThrow(
>>> 117:                             OperatingSystem.isAix() ? "_posix_getpwuid_r" : "getpwuid_r"),
>>> 118:                     FunctionDescriptor.of(C_INT,
>> 
>> Indentation could be improved, here.
>
> Do you have a suggestion? I intentionally indented based on argument nesting. `FunctionDescriptor.of(...` is the 2nd argument of `downcallHandle` so I indented one level (8 spaces) to the method. `OperatingSystem.isAix()...` is argument of `findOrThrow` and `calling_convention_requires_int_as_long...` etc are arguments of `FunctionDescriptor.of` and they are indented one level further. IntelliJ IDEA unindents the `FunctionDescriptor.of(...)` block but I think that's misleading.

As for whether it's a better alternative of JNI, FFM is usually considered at least as fast as JNI. In this case, on my Mac, the FFM version is much much faster. I guess the main reason is while the C code is quite small it calls back to Java object manipulation too much.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28931#discussion_r2714356450