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Problem with DLL

mondixon (11)
Hi everyone, i have recently created dll file with plan to use InternetOpen in order to make simple web request but when i load it or start it with rundll32, nothing happens.

In case it's standalone exe file web request is made successfully. Also i should mention it doesnt even work when i try to execute it with CreateRemoteThread on DLL_PROCESS_ATTACH event.


Here is my code

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  #undef UNICODE
#include <windows.h>
#include <WinInet.h>

#define EXPORT extern "C" __declspec(dllexport)

EXPORT void RequestFunc()
{
	
	HINTERNET hSession = InternetOpen("MyAgent", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
	HINTERNET hConnect = InternetConnect(hSession, "www.google.com", INTERNET_DEFAULT_HTTP_PORT, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 1);
	HINTERNET hRequest = HttpOpenRequest(hConnect, "POST", "/test.txt", NULL, NULL, 0, 0, 1);
	HttpSendRequest(hRequest, 0, 0, 0, 0);

	InternetCloseHandle(hSession);
	InternetCloseHandle(hConnect);
	InternetCloseHandle(hRequest);

	
}


BOOL WINAPI DllMain(HMODULE hModule, DWORD  ul_reason_for_call, LPVOID lpReserved)
{
	switch (ul_reason_for_call)
	{
	case DLL_PROCESS_ATTACH:
	case DLL_THREAD_ATTACH:
	case DLL_THREAD_DETACH:
	case DLL_PROCESS_DETACH:
		break;
	}
	return TRUE;
}
Thomas1965 (4571)
Why don't you set a breakpoint at the beginning of RequestFunc() and step through it with the debugger and see what happens.
coder777 (8444)
Beside what Thomas1965 stated you should check the result of the functions whether they were successful or not. If not output somehow the error using GetLastError(). See:

https://docs.microsoft.com/en-us/windows/desktop/api/wininet/nf-wininet-internetopena
mondixon (11)
Debugger shows nothing, i put simple MessageBox and it display correctly but only in case when its before HttpSendRequest, if its after HttpSendRequest, nothing pops out.
mondixon (11)
I've tried something like this but neither of message boxes pops out, it fail at HttpSendRequest but nothing comes back.

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#undef UNICODE
#include <windows.h>
#include <WinInet.h>

#define EXPORT extern "C" __declspec(dllexport)

EXPORT void RequestFunc()
{
	
	/*
	HINTERNET hInternetOpen		= InternetOpen("HTTPGET", INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, 0);
	HINTERNET hInternetConnect  = InternetConnect(hInternetOpen, "www.rottentomatoes.com", INTERNET_DEFAULT_HTTP_PORT,NULL, NULL, INTERNET_SERVICE_HTTP, 0, 0);
	HINTERNET m_hRequest		= HttpOpenRequest(hInternetConnect,"GET","/index.jsp","HTTP/1.1",NULL, NULL,INTERNET_FLAG_RELOAD | INTERNET_FLAG_EXISTING_CONNECT, 0);
	*/
	MessageBoxA(0, "William", "Krauss", 0);

	// for clarity, error-checking has been removed
	HINTERNET hSession = InternetOpen("MyAgent", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
	HINTERNET hConnect = InternetConnect(hSession, "www.google.com", INTERNET_DEFAULT_HTTP_PORT, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 1);
	HINTERNET hRequest = HttpOpenRequest(hConnect, "POST", "/test.txt", NULL, NULL, 0, 0, 1);
	HttpSendRequest(hRequest, 0, 0, 0, 0);
	// close any valid internet-handles 

	InternetCloseHandle(hSession);
	InternetCloseHandle(hConnect);
	InternetCloseHandle(hRequest);
	/*
	InternetCloseHandle(hInternetOpen);
	InternetCloseHandle(hInternetConnect);
	InternetCloseHandle(m_hRequest);
	*/

	
}

DWORD WINAPI RequestThread() {

	

	// for clarity, error-checking has been removed
	HINTERNET hSession = InternetOpen("MyAgent", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
	
	HINTERNET hConnect = InternetConnect(hSession, "www.google.com", INTERNET_DEFAULT_HTTP_PORT, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 1);
	HINTERNET hRequest = HttpOpenRequest(hConnect, "POST", "/test.txt", NULL, NULL, 0, 0, 1);
	MessageBox(NULL, "TEST", "TEST", MB_OK);
	if (!HttpSendRequestA(hRequest, 0, 0, 0, 0)) {
		MessageBox(NULL, "FAIL", "FAIL", MB_OK);
	}
	else {
		MessageBox(NULL, "ALL OK", "OK", MB_OK);
	}
		

	
	// close any valid internet-handles 

	InternetCloseHandle(hSession);
	InternetCloseHandle(hConnect);
	InternetCloseHandle(hRequest);

	return 0;
}


BOOL WINAPI DllMain(HMODULE hModule, DWORD  ul_reason_for_call, LPVOID lpReserved)
{
	switch (ul_reason_for_call)
	{
	case DLL_PROCESS_ATTACH:
		CreateRemoteThread(NULL, NULL, RequestThread(), NULL, NULL, NULL, NULL);

	case DLL_THREAD_ATTACH:
	case DLL_THREAD_DETACH:
	case DLL_PROCESS_DETACH:
		break;
	}
	return TRUE;
}
coder777 (8444)
Again: I suggest to use GetLastError() possibly in conjunction with FormatMessage(...) in order to find out what is going wrong:

https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-formatmessage
mondixon (11)
Thank you problem is fixed.
Thomas1965 (4571)
What did you do?
Other people might have the same problem so it would be nice to share your solution
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