RFR: JDK-8275703: System.loadLibrary fails on Big Sur for libraries hidden from filesystem

[Mandy Chung]

On Wed, 27 Oct 2021 02:51:24 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> On, macOS 11.x, system libraries are loaded from dynamic linker cache.  The libraries are no longer present on the filesystem.   `NativeLibraries::loadLibrary` checks for the file existence before calling `JVM_LoadLibrary`.   Such check no longer applies on Big Sur.   This proposes that on macOS >= 11, it will skip the file existence check and attempt to load a library for each path from java.library.path and system library path.
>
> src/java.base/macosx/classes/jdk/internal/loader/ClassLoaderHelper.java line 44:
> 
>> 42:             } catch (NumberFormatException e) {}
>> 43:         }
>> 44:         hasDynamicLoaderCache = major >= 11;
> 
> Hello Mandy,
> I'm not too familiar with MacOS versioning schemes. However, in this specific logic, if the `os.version` value doesn't contain a dot character, then the `major` is initialized to `11`, which would then evaluate this `hasDynamicLoaderCache` to `true`. That would mean if the `os.version` is (for example) `10`, then `hasDynamicLoaderCache` will be incorrectly set to `true` here, isn't it?

macOS product version contains 3 parts: major, minor, and patch version.  But it does not hurt  to handle the case where no dot exists in the string.


        int major = 11;
        int i = osVersion.indexOf('.');
        try {
            major = Integer.parseInt(i < 0 ? osVersion : osVersion.substring(0, i));
        } catch (NumberFormatException e) {}

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PR: https://git.openjdk.java.net/jdk/pull/6127