feat(natsock): patch Netty's native epoll transport library by symbol

[kaahos]

What does this PR do?:

Extends native socket patching to detect Netty's native epoll transport library (libnetty_transport_native_epoll*.so) by exported symbol, so it can be patched even when it lives outside the JDK's lib directory and its filename is relocated under shading (e.g. grpc-netty-shaded).

Motivation:

Netty's native epoll transport bypasses the JDK's socket path, so socket-related events were missed for applications using it.

Additional Notes:

Detection matches on JNI_OnLoad_netty_transport_native_epoll / JNI_OnUnload_netty_transport_native_epoll symbol pairs rather than basename, mirroring the existing IBM JCL bridge all-or-nothing check.

How to test the change?:

New unit tests in nativeSocketInterposer_ut.cpp cover plain and shaded Netty native epoll libraries, plus rejection when only one of the two symbols is present.

For Datadog employees:

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  bewaire also runs automatically on every PR.
• This PR doesn't touch any of that.
• JIRA: [JIRA-XXXX]

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[dd-octo-sts]

CI Test Results

Run: #32473717914 | Commit: 7c8cc45 | Duration: 17m 16s (longest job)

✅ All 32 test jobs passed

Status Overview

JDK	glibc-aarch64/debug	glibc-amd64/debug	musl-aarch64/debug	musl-amd64/debug
8	-	✅	-	-
8-ibm	-	✅	-	-
8-j9	✅	✅	-	-
8-librca	-	-	✅	✅
8-orcl	-	✅	-	-
11	-	✅	-	-
11-j9	✅	✅	-	-
11-librca	-	-	✅	✅
17	✅	✅	-	-
17-graal	✅	✅	-	-
17-j9	✅	✅	-	-
17-librca	-	-	✅	✅
21	✅	✅	-	-
21-graal	✅	✅	-	-
21-librca	-	-	✅	✅
25	✅	✅	-	-
25-graal	✅	✅	-	-
25-librca	-	-	✅	✅

Legend: ✅ passed | ❌ failed | ⚪ skipped | 🚫 cancelled

Summary: Total: 32 | Passed: 32 | Failed: 0

---

Updated: 2026-08-21 11:11:36 UTC

[datadog-official]

🔄 Datadog auto-retried 2 jobs - 2 passed on retry

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 0bd231e | Docs | View more details | Give us feedback!}

[dd-octo-sts]

Scan-Build Report

User:	runner@runnervm76f27
Working Directory:	/home/runner/work/java-profiler/java-profiler/ddprof-lib/src/test/make
Command Line:	make -j4 all
Clang Version:	Ubuntu clang version 18.1.3 (1ubuntu1)
Date:	Fri Aug 21 10:42:24 2026

Bug Summary

Bug Type	Quantity	Display?
All Bugs	1
Logic error
Dereference of null pointer	1

Reports

Bug Group	Bug Type ▾	File	Function/Method	Line	Path Length
Logic error	Dereference of null pointer	profiler.h	findLibraryByAddress	638	28

[dd-octo-sts]

✅ All 40 integration tests passed

📊 Dashboard · 👷 Pipeline · 📦 0bd231e1

[dd-octo-sts]

Reliability & Chaos Results

✅ All reliability & chaos checks passed Pipeline: https://gitlab.ddbuild.io/DataDog/java-profiler/-/pipelines/132370831

[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 0bd231e185

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[chatgpt-codex-connector]

Handle Netty libraries that have already been unlinked

When the Netty transport was loaded before native-I/O profiling starts, this selector is never reached under Netty's default io.netty.native.deleteLibAfterLoading=true: the mapping name ends in (deleted), and patch_socket_functions() skips it when realpath(lib->name(), ...) fails at lines 833-835. This leaves the common already-loaded/restart case entirely unpatched; identify Netty from the in-memory CodeCache before requiring a resolvable filesystem path.

Useful? React with 👍 / 👎.

[chatgpt-codex-connector]

Avoid scanning every library's full symbol table

On each library refresh while native-I/O hooks are active, every resolved DSO reaches this check before any basename or JDK-directory filtering, while CodeCache::findSymbol() performs a linear scan over all _count symbols. Large libraries such as libjvm contain far more than 256 entries, so loading one new DSO now rescans the complete symbol tables of all previously loaded libraries even when Netty is absent; cheaply narrow candidates first or provide an indexed exact-symbol lookup.

AGENTS.md reference: AGENTS.md:L385-L386

Useful? React with 👍 / 👎.