使用 JNA 调用 FFI 启动 EasyTier 然后收集网络信息时获得 null

[LinQingYuu]

我用 JNA 写了个包装器来调用 EasyTier

package io.github.linqingyuu.easytier.wrappers

import com.sun.jna.FunctionMapper
import com.sun.jna.Library
import com.sun.jna.Memory
import com.sun.jna.Native
import com.sun.jna.Pointer
import com.sun.jna.ptr.PointerByReference
import io.github.linqingyuu.easytier.wrappers.models.NetworkInfoKeyValuePair
import io.github.linqingyuu.easytier.wrappers.models.NetworkInformation
import io.github.linqingyuu.easytier.wrappers.models.WrapperException

class EasyTierWrapper(dllPath: String) : IEasyTierWrapper{
    val methodMapper = mapOf(
        Library.OPTION_FUNCTION_MAPPER to FunctionMapper{ _,method ->
            when(method.name){
                "parseConfig" -> "parse_config"
                "runNetworkInstance" -> "run_network_instance"
                "retainNetworkInstance" -> "retain_network_instance"
                "collectNetworkInfos" -> "collect_network_infos"
                "getErrorMsg" -> "get_error_msg"
                "freeString" -> "free_string"
                else -> method.name
            }
        })
    val wrapper: IEasyTierWrapper = Native.load(dllPath, IEasyTierWrapper::class.java,
        methodMapper
        )
        
    override fun parseConfig(config: String) = wrapper.parseConfig(config)
    override fun runNetworkInstance(config: String) = wrapper.runNetworkInstance(config)
    override fun retainNetworkInstance(names: Array<String>) = wrapper.retainNetworkInstance(names)
    override fun collectNetworkInfos(struct: Pointer, maxLength: Int) = wrapper.collectNetworkInfos(struct, maxLength)
    override fun getErrorMsg(msgString: PointerByReference) = wrapper.getErrorMsg(msgString)
    override fun freeString(string: Pointer) = wrapper.freeString(string)
    fun getLastError(): String{
        val message = PointerByReference()
        getErrorMsg(message)
        if(message.value == null) return ""
        return message.value.getString(0,"UTF-8")
    }
    fun getNetworkInformation(length: Int = 256):Array<NetworkInformation?> {
        try {
            val structSize = NetworkInfoKeyValuePair().size()
            val maxSize = (structSize * length)
            val memory = Memory(maxSize.toLong()) as Pointer
            val count = collectNetworkInfos(memory, maxSize)
            if (count < 0) throw WrapperException(getLastError())
            val structArray: Array<NetworkInformation?> = arrayOfNulls(length)
            val data = NetworkInfoKeyValuePair()
            for (i in 0 until count) {
                val structPtr = memory.share((i * structSize).toLong())
                data.useMemory(structPtr)
                data.read()
                structArray[i] = NetworkInformation(
                    data.key.getString(0, "UTF-8"),
                    data.value.getString(0, "UTF-8")
                )
                freeString(data.key)
                freeString(data.value)
            }
            return structArray
        }catch(ex: Exception){
            throw WrapperException(getLastError(), ex)
        }
    }
}

随后本地建了个 EasyTier 的服务端，将 EasyTier 客户端配置为使用此服务器进行信息交换和中继

当我开始运行测试后，弹出了 Windows 防火墙告警（到目前为止一切都很正常）

随后调用 getNetworkInformation 函数后，控制台输出了异常信息并退出

Unexpected exception thrown.
org.gradle.internal.remote.internal.MessageIOException: Could not write '/127.0.0.1:56328'.
	at org.gradle.internal.remote.internal.inet.SocketConnection.flush(SocketConnection.java:142)
	at org.gradle.internal.remote.internal.hub.MessageHub$ConnectionDispatch.run(MessageHub.java:333)
	at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
	at org.gradle.internal.concurrent.AbstractManagedExecutor$1.run(AbstractManagedExecutor.java:48)
	at java.base@21.0.10/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
	at java.base@21.0.10/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
	at java.base@21.0.10/java.lang.Thread.run(Thread.java:1595)
Caused by: java.io.IOException: Connection reset by peer
	at java.base@21.0.10/sun.nio.ch.SocketDispatcher.write0(Native Method)
	at java.base@21.0.10/sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:54)
	at java.base@21.0.10/sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:137)
	at java.base@21.0.10/sun.nio.ch.IOUtil.write(IOUtil.java:81)
	at java.base@21.0.10/sun.nio.ch.IOUtil.write(IOUtil.java:58)
	at java.base@21.0.10/sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:542)
	at org.gradle.internal.remote.internal.inet.SocketConnection$SocketOutputStream.writeWithNonBlockingRetry(SocketConnection.java:282)
	at org.gradle.internal.remote.internal.inet.SocketConnection$SocketOutputStream.writeBufferToChannel(SocketConnection.java:269)

目测应该是 JVM 挂掉了，之前还有一个 Value can not NULL 的错误，不过我现在复现不出来

类定义和项目配置如下，配置项是从网页控制台生成的

https://gist.github.com/LinQingYuu/68b0bab9f52ab786a845e81fd0d3af9e

对 EasyTier 和 JVM P/Invoke 不太熟，写错了轻点喷

[KKRainbow]

感觉你发的这个错不是 et 报出来的，这个是全部的报错了么，控制台有没有其他包含 "easytier" 文本的错误打印。我猜测应该也是 et 某个地方实现有 bug，但是现在信息有点少不太好判断

[LinQingYuu]

感觉你发的这个错不是 et 报出来的，这个是全部的报错了么，控制台有没有其他包含 "easytier" 文本的错误打印。我猜测应该也是 et 某个地方实现有 bug，但是现在信息有点少不太好判断

getLastError 没有返回任何东西说是，但是从给的 count 上来看应该是成功了

由于 Gradle 有点破烂，只要 JVM 彻底死了就会抛这个错误而不是具体到哪里炸了，我也没招

Exception in thread "main" io.github.linqingyuu.easytier.wrappers.models.WrapperException: 
	at io.github.linqingyuu.easytier.wrappers.EasyTierWrapper.getNetworkInformation(EasyTierWrapper.kt:70)
	at io.github.linqingyuu.easytier.wrappers.EasyTierWrapper.getNetworkInformation$default(EasyTierWrapper.kt:48)
	at io.github.linqingyuu.easytier.wrappers.EasyTierWrapperKt.main(EasyTierWrapper.kt:115)
	at io.github.linqingyuu.easytier.wrappers.EasyTierWrapperKt.main(EasyTierWrapper.kt)
Caused by: java.lang.NullPointerException: NULL must not be null
	at io.github.linqingyuu.easytier.wrappers.models.NetworkInfoKeyValuePair.<init>(NetworkInfoKeyValuePair.kt:8)
	at io.github.linqingyuu.easytier.wrappers.EasyTierWrapper.getNetworkInformation(EasyTierWrapper.kt:50)
	... 3 more

对应的代码

fun getNetworkInformation(length: Int = 256):Array<NetworkInformation?> {
        try {
            val structSize = NetworkInfoKeyValuePair().size()
            val maxSize = (structSize * length)
            val memory = Memory(maxSize.toLong()) as Pointer
            val count = collectNetworkInfos(memory, maxSize)
            if (count < 0) throw WrapperException(getLastError())
            val structArray: Array<NetworkInformation?> = arrayOfNulls(length)
            val data = NetworkInfoKeyValuePair()
            for (i in 0 until count) {
                val structPtr = memory.share((i * structSize).toLong())
                data.useMemory(structPtr)
                data.read()
                structArray[i] = NetworkInformation(
                    data.key.getString(0, "UTF-8"),
                    data.value.getString(0, "UTF-8")
                )
                freeString(data.key)
                freeString(data.value)
            }
            return structArray
        }catch(ex: Exception){
            throw WrapperException(getLastError(), ex)
        }
    }

按照 C# 的示例写的

总不能给多少 length 返回多少吧