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Daniel Zou e04803daec
Modify OpenSSL native library loading to accommodate GraalVM (#10395)
**Motivation:**

We are interested in building Netty libraries with Ahead-of-time compilation with GraalVM. We saw there was [prior work done on this](https://github.com/netty/netty/search?q=graalvm&unscoped_q=graalvm). We want to introduce a change which will unblock GraalVM support for applications using netty and `netty-tcnative`.

This solves the error [that some others encounter](https://github.com/oracle/graal/search?q=UnsatisfiedLinkError+sslOpCipherServerPreference&type=Issues):

```
Exception in thread "main" java.lang.UnsatisfiedLinkError: io.grpc.netty.shaded.io.netty.internal.tcnative.NativeStaticallyReferencedJniMethods.sslOpCipherServerPreference()I [symbol: Java_io_grpc_netty_shaded_io_netty_internal_tcnative_NativeStaticallyReferencedJniMethods_sslOpCipherServerPreference or Java_io_grpc_netty_shaded_io_netty_internal_tcnative_NativeStaticallyReferencedJniMethods_sslOpCipherServerPreference__]
```

**Modification:**

The root cause of the issue is that in the tcnative libraries, the [`SSL.java` class](783a8b6b69/openssl-dynamic/src/main/java/io/netty/internal/tcnative/SSL.java (L67)) references a native call in the static initialization of the class - the method `sslOpCipherServerPreference()` on line 67 is used to initialize the static variable. But you see that `OpenSsl` also uses[ `SSL.class` to check if `netty-tcnative` is on the classpath before loading the native library](cbe238a95b/handler/src/main/java/io/netty/handler/ssl/OpenSsl.java (L123)). 

So this is the problem because in ahead-of-time compilation, when it references the SSL class, it will try to load those static initializers and make the native library call, but it cannot do so because the native library has not been loaded yet since the `SSL` class is being referenced to check if the library should be loaded in the first place.

**Solution:** So the proposed solution here is to just choose a different class in the `tcnative` package which does not make a native library call during static initialization. I just chose `SSLContext` if this is OK.

This should have no negative effects other than unblocking the GraalVM use-case.

**Result:**

It fixes the unsatisfied link error. It will fix error for future users; it is a common error people encounter.
2020-07-08 10:46:38 +02:00
.github Change the netty.io homepage scheme(http -> https) (#9344) 2019-07-09 21:09:42 +02:00
.mvn Use latest maven release (#9820) 2019-11-27 14:45:28 +01:00
all Include aarch64 packages in netty-bom (#10292) 2020-05-15 10:12:46 +02:00
bom Include aarch64 packages in netty-bom (#10292) 2020-05-15 10:12:46 +02:00
buffer Include more details if we throw an IllegalArgumentException because of overflow (#10330) 2020-06-02 10:07:50 +02:00
codec [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
codec-dns [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
codec-haproxy [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
codec-http Add option to HttpObjectDecoder to allow duplicate Content-Lengths (#10349) 2020-07-06 10:25:13 +02:00
codec-http2 Add detailed error message corresponding to the IndexOutOfBoundsException while calling getEntry(...) (#10386) 2020-07-06 10:19:22 +02:00
codec-memcache [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
codec-mqtt [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
codec-redis [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
codec-smtp [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
codec-socks [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
codec-stomp [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
codec-xml [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
common Do not report ReferenceCountedOpenSslClientContext$ExtendedTrustManagerVerifyCallback.verify as blocking call (#10387) 2020-07-06 09:08:44 +02:00
dev-tools [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
docker Update GraalVM with JDK 8 and add GraalVM with JDK 11 (#10333) 2020-06-02 11:52:55 +02:00
example Fix #10261 stomp can be chunked, so implement StompWebSocketFrameEncoder (#10274) 2020-06-04 19:14:13 +02:00
handler Modify OpenSSL native library loading to accommodate GraalVM (#10395) 2020-07-08 10:46:38 +02:00
handler-proxy [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
license Introduce MacOSDnsServerAddressStreamProvider which correctly detect all nameserver configuration on MacOS (#9161) 2019-10-28 15:02:45 +01:00
microbench [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
resolver [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
resolver-dns Fix possible StackOverflowError when try to resolve authorative names… (#10337) 2020-06-04 17:56:59 +02:00
resolver-dns-native-macos [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
tarball [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
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testsuite-shading [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
transport Expand ChannelPipeline javadocs to cover UnorderedThreadPoolEventExecutor (#10361) 2020-06-23 09:28:34 +02:00
transport-blockhound-tests Do not report ReferenceCountedOpenSslClientContext$ExtendedTrustManagerVerifyCallback.verify as blocking call (#10387) 2020-07-06 09:08:44 +02:00
transport-native-epoll [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
transport-native-kqueue [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
transport-native-unix-common [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
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transport-udt [maven-release-plugin] prepare for next development iteration 2020-05-13 06:00:23 +00:00
.fbprefs Updated Find Bugs configuration 2009-03-04 10:33:09 +00:00
.gitattributes Include mvn wrapper to make setup of development env easier 2018-01-26 08:13:17 +01:00
.gitignore Add vscode specific files / directory to .gitignore (#9652) 2019-10-10 09:35:08 +04:00
.lgtm.yml Enables lgtm.com to process this project and create a CodeQL database 2020-01-17 11:05:53 +01:00
CONTRIBUTING.md Change the netty.io homepage scheme(http -> https) (#9344) 2019-07-09 21:09:42 +02:00
LICENSE.txt Relicensed to Apache License v2 2009-08-28 07:15:49 +00:00
mvnw Include mvn wrapper to make setup of development env easier 2018-01-26 08:13:17 +01:00
mvnw.cmd Include mvn wrapper to make setup of development env easier 2018-01-26 08:13:17 +01:00
NOTICE.txt Introduce MacOSDnsServerAddressStreamProvider which correctly detect all nameserver configuration on MacOS (#9161) 2019-10-28 15:02:45 +01:00
pom.xml Update to netty-tcnative 2.0.31.Final and make SslErrorTest more robust (#10392) 2020-07-07 10:50:03 +02:00
README.md Change the netty.io homepage scheme(http -> https) (#9344) 2019-07-09 21:09:42 +02:00
run-example.sh Add DNS client examples for run-example.sh (#10283) 2020-05-14 12:10:32 +02:00

Netty Project

Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients.

How to build

For the detailed information about building and developing Netty, please visit the developer guide. This page only gives very basic information.

You require the following to build Netty:

Note that this is build-time requirement. JDK 5 (for 3.x) or 6 (for 4.0+) is enough to run your Netty-based application.

Branches to look

Development of all versions takes place in each branch whose name is identical to <majorVersion>.<minorVersion>. For example, the development of 3.9 and 4.0 resides in the branch '3.9' and the branch '4.0' respectively.

Usage with JDK 9

Netty can be used in modular JDK9 applications as a collection of automatic modules. The module names follow the reverse-DNS style, and are derived from subproject names rather than root packages due to historical reasons. They are listed below:

  • io.netty.all
  • io.netty.buffer
  • io.netty.codec
  • io.netty.codec.dns
  • io.netty.codec.haproxy
  • io.netty.codec.http
  • io.netty.codec.http2
  • io.netty.codec.memcache
  • io.netty.codec.mqtt
  • io.netty.codec.redis
  • io.netty.codec.smtp
  • io.netty.codec.socks
  • io.netty.codec.stomp
  • io.netty.codec.xml
  • io.netty.common
  • io.netty.handler
  • io.netty.handler.proxy
  • io.netty.resolver
  • io.netty.resolver.dns
  • io.netty.transport
  • io.netty.transport.epoll (native omitted - reserved keyword in Java)
  • io.netty.transport.kqueue (native omitted - reserved keyword in Java)
  • io.netty.transport.unix.common (native omitted - reserved keyword in Java)
  • io.netty.transport.rxtx
  • io.netty.transport.sctp
  • io.netty.transport.udt

Automatic modules do not provide any means to declare dependencies, so you need to list each used module separately in your module-info file.