Jetty 12.1 brotli linking problem

[wendigo]

Jetty version(s)

12.1.0

Jetty Environment

Java version/vendor (use: java -version)

24.0.2

OS type/version

Linux

[root@presto-worker-1 /]# /lib64/libc.so.6
GNU C Library (GNU libc) stable release version 2.34.
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 11.5.0 20240719 (Red Hat 11.5.0-5).
libc ABIs: UNIQUE ABSOLUTE
For bug reporting instructions, please see:
<https://www.gnu.org/software/libc/bugs.html>.

Linux presto-worker-1 6.14.10-orbstack-00291-g1b252bd3edea #1 SMP Sat Jun  7 02:45:18 UTC 2025 aarch64 aarch64 aarch64 GNU/Linux

Description

Brotli linking exception prevents server startup (this could happen in cases like: dynamic library cannot be loaded from the location that is mounted with noexec or brotli is linked against newer libc). It should be possible to apply brotli and any other compression conditionally, if it's available. Right now since the static blocks are used to check for native library availability, it's not possible to correctly intercept linking exception without the usage of reflection.

How to reproduce?

[sbordet]

I think we are already doing this.

What exception do you get exactly?

[joakime]

@sbordet it was mentioned in #13493 (comment)

presto-worker-2     | Caused by: java.lang.ExceptionInInitializerError: Exception java.lang.UnsatisfiedLinkError: Failed to load Brotli native library [in thread "main"]
presto-worker-2     |   at com.aayushatharva.brotli4j.Brotli4jLoader.ensureAvailability(Brotli4jLoader.java:108)
presto-worker-2     |   at org.eclipse.jetty.compression.brotli.BrotliCompression.<clinit>(BrotliCompression.java:54)

[wendigo]

@sbordet nope, exception is raised once class is linked, so you can't catch it (it would be better to move ensureAvailability() from static {} to constructor so we can fallback and disable brotli if it cannot be linked (compressor is created once so it doesn't affect performance anyway)

[sbordet]

We should be using the ServiceLoader to load compression implementations, and we should be catching any exception if the service implementation cannot be allocated, and discard that implementation.

There could be a lot of Compressor instances, for example when each web application decides to use their own CompressionHandler, so any other solution that is not a class static block must use a class lock.

How do you link brotli?

[wendigo]

@sbordet I don't. You are using brotli4j library

[sbordet]

Then I don't understand how the exception escapes.
We have quite a few tests where Brotli is not available, and we don't see any ExceptionInInitializerError.

Do you have a reproducer that we can try?

[wendigo]

ensureAvailability() is called in the static block in the BrotliCompression class. That's why exception cannot be caught

[sbordet]

ensureAvailability() is called in the static block in the BrotliCompression class. That's why exception cannot be caught

I don't think this is correct.

When the ServiceLoader loads the class name from the service file, it then tries to load and instantiate the class, which perform class initialization.
The load/instantiate call site can easily try/catch any exception and move to the next service class.
This is what we do (or should be doing).

We need a reproducer.

[wendigo]

I'm adding compression to the server programatically so serviceloader doesn't apply here.

[wendigo]

https://github.com/airlift/airlift/pull/1522/files#diff-9d8d77e537a69837978a5cfc5be80e1140ed54ef4618a572b3e1ba6e4f1b9075R289

[sbordet]

We could add a static BrotliCompression.newInstance() that calls Brotli4jLoader.ensureAvailability(), and possibly throws.

Would that be ok for you?

[wendigo]

yeah! that would allow us to wrap it with try catch :)

[wendigo]

Client has the same issue while using ServiceLoader to discover compressions:

presto-master       | Caused by: java.lang.ExceptionInInitializerError: Exception java.lang.UnsatisfiedLinkError: Failed to load Brotli native library [in thread "main"]
presto-master       |   at com.aayushatharva.brotli4j.Brotli4jLoader.ensureAvailability(Brotli4jLoader.java:108)
presto-master       |   at org.eclipse.jetty.compression.brotli.BrotliCompression.<clinit>(BrotliCompression.java:54)
presto-master       |   at java.base/jdk.internal.misc.Unsafe.ensureClassInitialized0(Native Method)
presto-master       |   at java.base/jdk.internal.misc.Unsafe.ensureClassInitialized(Unsafe.java:1166)
presto-master       |   at java.base/jdk.internal.reflect.MethodHandleAccessorFactory.ensureClassInitialized(MethodHandleAccessorFactory.java:341)
presto-master       |   at java.base/jdk.internal.reflect.MethodHandleAccessorFactory.newConstructorAccessor(MethodHandleAccessorFactory.java:104)
presto-master       |   at java.base/jdk.internal.reflect.ReflectionFactory.newConstructorAccessor(ReflectionFactory.java:143)
presto-master       |   at java.base/java.lang.reflect.Constructor.acquireConstructorAccessor(Constructor.java:546)
presto-master       |   at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:496)
presto-master       |   at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:483)
presto-master       |   at java.base/java.util.ServiceLoader$ProviderImpl.newInstance(ServiceLoader.java:707)
presto-master       |   at java.base/java.util.ServiceLoader$ProviderImpl.get(ServiceLoader.java:672)
presto-master       |   at java.base/java.util.ServiceLoader$2.next(ServiceLoader.java:1256)
presto-master       |   at org.eclipse.jetty.util.ServiceLoaderSpliterator.tryAdvance(ServiceLoaderSpliterator.java:39)
presto-master       |   at java.base/java.util.Spliterator.forEachRemaining(Spliterator.java:332)
presto-master       |   at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:570)
presto-master       |   at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:560)
presto-master       |   at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:153)
presto-master       |   at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:176)
presto-master       |   at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:265)
presto-master       |   at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:636)
presto-master       |   at org.eclipse.jetty.client.HttpClient.doStart(HttpClient.java:243)