injectcrypt.cpp

#include <iostream>

/*
 * Running on Linux:
 * LD_PRELOAD="libinjectcrypt.so" NecroDancer
 *
 * Running on OSX:
 * DYLD_INSERT_LIBRARIES=libinjectcrypt.dylib NecroDancer
 *
 * Running on Windows:
 * You need an external application to inject dll library
 * e.g https://github.com/Arvanaghi/Windows-DLL-Injector or CheatEngine
 */

void setup() {
    printf("HOOKED INTO GAME\n");
}

#ifdef _WIN32 // M$ Window$
    #include <windows.h>

    BOOL APIENTRY DllMain(HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserved) {
        if (ul_reason_for_call == DLL_PROCESS_ATTACH) {
            setup();
        }

        return TRUE;
    }
#else // Linux and OSX
    #include <dlfcn.h>
    #include <unistd.h>

    long int strtol(const char* str, char** endptr, int base) {
        static int (*original_strtol)(const char* str, char** endptr, int base) = nullptr;

        if (original_strtol == nullptr) {
            *(void **) (&original_strtol) = dlsym(RTLD_NEXT, "strtol");
            setup();
        }

        return original_strtol(str, endptr, base);
    }
#endif