dll path injection. depends on LoadLibrary()

dllinject.c

#include <windows.h>
#include <tlhelp32.h>

DWORD getProcessID() {
  DWORD processID = 0;
  HANDLE snapHandle;
  PROCESSENTRY32 processEntry = {0};

  if( (snapHandle = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0)) == INVALID_HANDLE_VALUE ) {
    return 0;
  }

  processEntry.dwSize = sizeof(PROCESSENTRY32);
  Process32First(snapHandle, &processEntry);
  do {
    if ( strcmp(processEntry.szExeFile, "notepad.exe") == 0 ) {
      return processEntry.th32ProcessID;
    }
  } while (Process32Next(snapHandle,&processEntry));

  if ( snapHandle != INVALID_HANDLE_VALUE ) {
    CloseHandle(snapHandle);
  }

  return 0;
} 

int inject_DLL(const char* file_name, int PID)
{
    HANDLE h_process = OpenProcess(PROCESS_ALL_ACCESS, FALSE, PID);                   //retrieving a handle to the process

    char fullDLLPath[_MAX_PATH];                                                      //getting the full path of the dll file
    GetFullPathNameA(file_name, _MAX_PATH, fullDLLPath, NULL);

    LPVOID DLLPath_addr = VirtualAllocEx(h_process, NULL, _MAX_PATH,
                          MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);          //allocating memory in the target process
    WriteProcessMemory(h_process, DLLPath_addr, fullDLLPath,
                       strlen(fullDLLPath), NULL);                                    //writing the dll path to that memory

    LPVOID LoadLib_addr = GetProcAddress(GetModuleHandleA("Kernel32"),
                                         "LoadLibraryA");                             //getting LoadLibraryA address (same across
                                                                                      //all processes) to start execution at it
    HANDLE h_rThread = CreateRemoteThread(h_process, NULL, 0, 
                       (LPTHREAD_START_ROUTINE)LoadLib_addr, DLLPath_addr, 0, NULL);  //starting a remote execution thread at
    WaitForSingleObject(h_rThread, INFINITE);                                         //LoadLibraryA and passing the dll path as
                                                                                      //an argument then waiting for it to be finished
    DWORD exit_code;
    GetExitCodeThread(h_rThread, &exit_code);                                         //Retrieving the module handle returned by LoadLibraryA

    CloseHandle(h_rThread);                                                           //Freeing the thread handle and the memory
    VirtualFreeEx(h_process, DLLPath_addr, 0, MEM_RELEASE);                           //allocated for the DLL path

    return 0;
}

int main(){

inject_DLL("dll.dll", (int)getProcessID() );

    return 0;
}