在嘗試訪問DLL函數時從JVM獲取EXCEPTION_ACCESS_VIOLATION

Question

我正在嘗試從我創建的自己的DLL文件訪問第三方DLL，但在使用JNI調用我自己的DLL時獲取JVM內存訪問沖突。

我試圖調用的第三方dll是cfint64.dll。 對於兼容性問題，我正在創建自己的dll來訪問第三方dll。

我不知道什么編譯器用於第三方cfint64.dll，但它應該是64位計算機。

在我這邊，這是我創建自己的DLL的方式：g ++ -I“％JAVA_HOME％\\ include”-I“％JAVA_HOME％\\ include \\ win32”-shared -o dll3minterface.dll DLL3MInterface.cpp

我知道第三方dll具有以下功能簽名：

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class dllCommunication */

#ifndef _Included_dllCommunication
#define _Included_dllCommunication
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     dllCommunication
 * Method:    nJavaInitInstance
 * Signature: (Ljava/lang/String;)I
 */
JNIEXPORT jint JNICALL Java_dllCommunication_nJavaInitInstance
  (JNIEnv *, jobject, jstring);



#ifdef __cplusplus
}
#endif
#endif

我創建的頭文件如下：

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_artificialmedgui_coderdx_DLL3MInterface */

#ifndef _Included_com_artificialmedgui_coderdx_DLL3MInterface
#define _Included_com_artificialmedgui_coderdx_DLL3MInterface
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     com_artificialmedgui_coderdx_DLL3MInterface
 * Method:    nJavaInitInstance
 * Signature: (Ljava/lang/String;)I
 */
JNIEXPORT jint JNICALL Java_com_artificialmedgui_coderdx_DLL3MInterface_nJavaInitInstance(JNIEnv *, jobject, jstring);

#ifdef __cplusplus
}
#endif
#endif

導致內存訪問沖突的.cpp文件如下所示。 請注意，導致錯誤的行是funcCall（inJNIStr）;. 如果我注釋掉這個函數調用，程序結束沒有錯誤。

#include <windows.h>
#include <jni.h>       // JNI header provided by JDK
#include <iostream>    // C++ standard IO header
#include "com_artificialmedgui_coderdx_DLL3MInterface.h"  // Generated
using namespace std;

typedef int (__stdcall* initInstanceFunc)(jstring);

JNIEXPORT jint JNICALL Java_com_artificialmedgui_coderdx_DLL3MInterface_nJavaInitInstance(JNIEnv *env, jobject, jstring inJNIStr) {
    // Step 1: Convert the JNI String (jstring) into C-String (char*)
   const char *inCStr = env->GetStringUTFChars(inJNIStr, NULL);



    HINSTANCE hGetProcIDDLL = LoadLibrary("C:\\workspace\\AMI3MDLLInterface\\resources\\cfint64.dll");

  if (!hGetProcIDDLL) {
    std::cout << "could not load the dynamic library" << std::endl;
    return EXIT_FAILURE;
  }
  else{
      std::cout << "Loaded cfint64.dll library!!!!" << std::endl;
  }

  // resolve function address here
  initInstanceFunc funcCall = (initInstanceFunc)GetProcAddress(hGetProcIDDLL, "Java_dllCommunication_nJavaInitInstance");
     if (*funcCall != NULL) {
      funcCall(inJNIStr);
  }
  else{
      std::cout << "Function is invalid" << std::endl;
  }


       return 1; //Testing
    }

我能夠加載第三方cfint64.dll，但在調用其中一個函數時，如funcCall（inJNIStr）; 它會拋出錯誤。
也許我在調用cfint64.dll函數時沒有從我的.cpp文件傳遞正確的String數據類型？ 我不是C ++程序員，所以任何想法都會引起問題。

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0000000000000000, pid=12276, tid=11080
#
# JRE version: Java(TM) SE Runtime Environment (10.0.1+10) (build 10.0.1+10)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (10.0.1+10, mixed mode, tiered, compressed oops, g1 gc, windows-amd64)
# Problematic frame:
# C  0x0000000000000000
#
# No core dump will be written. Minidumps are not enabled by default on client versions of Windows
#
# If you would like to submit a bug report, please visit:
#   http://bugreport.java.com/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
#

---------------  S U M M A R Y ------------

Command Line: com.artificialmedgui.coderdx.DLL3MInterface

Host: Intel(R) Core(TM) i7-4720HQ CPU @ 2.60GHz, 8 cores, 15G,  Windows 10 , 64 bit Build 17134 (10.0.17134.648)
Time: Sun Mar 24 14:15:30 2019 Eastern Daylight Time elapsed time: 1 seconds (0d 0h 0m 1s)

---------------  T H R E A D  ---------------

Current thread (0x000001421b910800):  JavaThread "main" [_thread_in_native, id=11080, stack(0x0000003371700000,0x0000003371800000)]

Stack: [0x0000003371700000,0x0000003371800000],  sp=0x00000033717ff258,  free space=1020k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)

Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
j  com.artificialmedgui.coderdx.DLL3MInterface.nJavaInitInstance(Ljava/lang/String;)I+0
j  com.artificialmedgui.coderdx.DLL3MInterface.main([Ljava/lang/String;)V+17
v  ~StubRoutines::call_stub

siginfo: EXCEPTION_ACCESS_VIOLATION (0xc0000005), data execution prevention violation at address 0x0000000000000000


Register to memory mapping:

RIP=0x0000000000000000 is an unknown value
RAX=0x00000006d0a4b6c0 is an oop
java.lang.String 
{0x00000006d0a4b6c0} - klass: 'java/lang/String'
RBX={method} {0x000001423eb204a8} 'nJavaInitInstance' '(Ljava/lang/String;)I' in 'com/artificialmedgui/coderdx/DLL3MInterface'
RCX=0x00000033717ff380 is pointing into the stack for thread: 0x000001421b910800
RDX=0x0000000000000002 is an unknown value
RSP=0x00000033717ff258 is pointing into the stack for thread: 0x000001421b910800
RBP=0x00000033717ff2d0 is pointing into the stack for thread: 0x000001421b910800
RSI=0x0000000000000002 is an unknown value
RDI=0x00000033717ff380 is pointing into the stack for thread: 0x000001421b910800
R8 =0x0000000000000000 is an unknown value
R9 =0x0000000000000000 is an unknown value
R10=0x0000000000000002 is an unknown value
R11=0x00000033717fef80 is pointing into the stack for thread: 0x000001421b910800
R12=0x0000000000000000 is an unknown value
R13={method} {0x000001423eb204a8} 'nJavaInitInstance' '(Ljava/lang/String;)I' in 'com/artificialmedgui/coderdx/DLL3MInterface'
R14=0x00000033717ff388 is pointing into the stack for thread: 0x000001421b910800
R15=0x000001421b910800 is a thread

Answer 1

我解決了這個問題。 也許我從一開始就沒有說清楚，但是我的JNI DLL正在調用另一個第三方JNI DLL。 因此，當您從Java代碼調用JNI DLL時，您只需要傳遞實際參數。 JVM Linker我想在調用實際的DLL函數時會添加其他參數。 無論如何，我只需要傳遞JVM鏈接器可能傳遞的這些附加參數。

要調用第二個JNI DLL函數：

Wrong:
typedef int (__stdcall* initInstanceFunc)(jstring);

Works:
typedef int (__stdcall* initInstanceFunc)(JNIEnv*,jobject,jstring);
...
funcCall(env,obj,inJNIStr);