Need to try all paths listed by 'java.library.path' before throwing UnsatisfiedLinkError

[Sanne]

I believe this could be the fix for #438

The code in :

graal/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jdk/NativeLibrarySupport.java

Lines 91 to 95 in cbadcf6

	public void loadLibrary(String name, boolean isAbsolute) {
	if (paths == null) {
	String[] tokens = SubstrateUtil.split(System.getProperty("java.library.path", ""), File.pathSeparator);
	paths = Arrays.stream(tokens).map(t -> t.isEmpty() ? "." : t).toArray(String[]::new);
	}

is able to deal with the requirement to list multiple paths for the java.library.path system property, but then the code attempting to load the libraries is expecting to have "false" returned on failure from one path, so to try the next path.

However the failed attempt to load the library from the first path immediately causes an UnsatisfiedLinkError to be thrown, so the additional paths are never tested.

see also:

• Fix SSL on Mac OS X with GraalVM 1.0.0-rc14 quarkusio/quarkus#1674

I'd be happy to add an integration test, but I'm not familiar with how you might prefer something like this to be structured. If you could point me to something similar I'd be glad to learn and try putting one together.

Thanks

[AzeemJiva]

Did you run manual tests? Various permutations (single path exception thrown or not, multiple paths, etc)? Looks reasonable but question what happens if the last path in the list doesn't satisfy the linker?

[Sanne]

hi @AzeemJiva , yes I tested this with local builds and it fixes all our issues with loading libraries.

If no single path satisfies the loading, an UnsatisfiedLinkError is thrown: same semantics as previously.

[Sanne]

@AzeemJiva @cstancu could you please have a look?

This is a blocker to use SSL / https on Linux, we'd really hope to have it in a release soon.

[AzeemJiva]

LGTM, but I don't have merge permissions.

[peter-hofer]

Thank you for your submission.

[Sanne]

thanks all!