Question

这是一个非常有趣的问题。在 native 代码打印其中的一些语句后，我得到了提到的异常。抛出的异常是：

hookThreadHandle is not NULL

hookThreadHandle is not NULL
Exception in thread "main" java.lang.UnsatisfiedLinkError: W:\elita\jnitesters\
workspace\c\MyHook\bin\Debug\MyHook.dll: A dynamic link library (DLL) initialization r
outine failed
    at java.lang.ClassLoader$NativeLibrary.load(Native Method)
    at java.lang.ClassLoader.loadLibrary0(Unknown Source)
    at java.lang.ClassLoader.loadLibrary(Unknown Source)
    at java.lang.Runtime.loadLibrary0(Unknown Source)
    at java.lang.System.loadLibrary(Unknown Source)
    at keylogger.TestKeys.main(TestKeys.java:12)

前两个语句hookThreadHandle is not NULL是初始化失败的dll语句！为什么在实际找到dll然后打印语句后抛出异常。？

什么是A dynamic link library (DLL) initialization routine failed例外？它意味着什么？

Java代码：

package keylogger;

public class TestKeys {
private static int i = 0;
private native void setWinHook();
private native void unregisterWinHook();

public static void main(String args[]) {

    //TestKeys o = new TestKeys();

    System.loadLibrary("MyHook"); // load the library that registers the hook


    Runnable r = new Runnable() {
        @Override
        public void run() {
            try {
                System.out.println("Sleeping for 10 seconds..");
                Thread.sleep(10000);
            }catch(Exception exc) {
                exc.printStackTrace();
            }
        }
    };
    new Thread(r,"new thread").start();       
 }
}

C代码：

#include <stdio.h>
#include <windows.h>
#include <w32api.h>
#include "keylogger_TestKeys.h"

static HHOOK handleKeyboardHook = NULL;
HINSTANCE hInst = NULL;
static DWORD hookThreadId = 0;
static HANDLE hookThreadHandle = NULL;
BOOL WINAPI installHook(HINSTANCE hinstDLL, DWORD fwdReason, LPVOID lpvReserved);

static LRESULT CALLBACK LowLevelKeyboardProc(int nCode, WPARAM wParam, LPARAM lParam) {

 printf("You pressed the key !\n");

 return CallNextHookEx(handleKeyboardHook, nCode, wParam, lParam);
}


BOOL WINAPI DllMain( HINSTANCE hinstDLL, DWORD fwdReason, LPVOID lpvReserved) {
  LPTHREAD_START_ROUTINE lpStartAddress = &installHook;
  hookThreadHandle = CreateThread(NULL, 0, lpStartAddress, NULL, 0, &hookThreadId);
  if(hookThreadHandle == NULL) {
    printf("\nhookThreadHandle is NULL\n");
  } else {
      printf("\nhookThreadHandle is not NULL\n");
   }
}

JNIEXPORT void JNICALL Java_keylogger_TestKeys_unregisterWinHook
 (JNIEnv *env, jobject obj) {
   if(handleKeyboardHook != NULL) {
     UnhookWindowsHookEx(handleKeyboardHook);
     printf("Keyboard hook successfully unregistered !");
   } else {
       printf("Coudn't Unhook the keyboard hook !");
     }
 }

BOOL WINAPI installHook(HINSTANCE hinstDLL, DWORD fwdReason, LPVOID lpvReserved) {

handleKeyboardHook = SetWindowsHookEx(WH_KEYBOARD_LL, LowLevelKeyboardProc, hinstDLL, 0);
MSG msg;

while(GetMessage(&msg, NULL, 0, 0))
{
  TranslateMessage(&msg);
  DispatchMessage(&msg);
}
return msg.wParam;

}

可能是什么原因？ Output on the CMD

Answer 1

DllMain应返回BOOL，表示它是否成功。来自MSDN：

当系统调用带有DllMain值的DLL_PROCESS_ATTACH函数时，如果成功则返回TRUE;如果初始化失败，则返回FALSE。如果在调用FALSE时返回值为DllMain，因为该流程使用LoadLibrary函数，LoadLibrary会返回NULL。（系统立即使用DLL_PROCESS_DETACH调用您的入口点函数并卸载DLL。）如果在进程初始化期间调用FALSE时返回值为DllMain，则进程将终止并显示错误。要获取扩展错误信息，请致电GetLastError。

您的函数缺少必要的return语句。

线程“main”中的异常java.lang.UnsatisfiedLinkError：动态链接库（DLL）初始化例程失败

1 个答案: