#include <windows.h>
#include <stdio.h>

#define log_info(msg, ...) printf("[*] " msg "\n", ##__VA_ARGS__)
#define log_err(msg, ...)  printf("[-] " msg "\n", ##__VA_ARGS__)
#define log_ok(msg, ...)   printf("[+] " msg "\n", ##__VA_ARGS__)

wchar_t dll_path[] = L"my-dll.dll";

int main(int argc, char **argv) {
	if (argc < 2) {
		log_err("Usage: %s <PID>", argv[0]);
		return -1;
	}

	DWORD pid = atoi(argv[1]);
	log_info("Using PID: %ld", pid);

	HANDLE process = OpenProcess(PROCESS_ALL_ACCESS, FALSE, pid);
	if (process == NULL) {
		log_err("Failed to open process handle: %ld", GetLastError());
		return -1;
	}
	log_ok("Sucessfully opened process handle");
	
	LPVOID buffer = VirtualAllocEx(process, NULL, sizeof(dll_path), (MEM_COMMIT | MEM_RESERVE), PAGE_READWRITE);
	if (buffer == NULL) {
		log_err("Failed to allocate buffer in process: %ld", GetLastError());
		CloseHandle(process);
		return -1;
	}
	log_ok("Successfully allocated a %lld byte buffer", sizeof(dll_path));

	WriteProcessMemory(process, buffer, dll_path, sizeof(dll_path), NULL);
	log_info("Wrote DLL path to buffer");
	
	HMODULE kernel32 = GetModuleHandleW(L"Kernel32");
	if (kernel32 == NULL) {
		log_err("Failed to open 'Kernel32' module: %ld", GetLastError());
		CloseHandle(process);
		return -1;
	}
	log_ok("Got ahdle to Kernel32.dll: 0x%p", kernel32);

	LPTHREAD_START_ROUTINE thread_callback = (LPTHREAD_START_ROUTINE)GetProcAddress(kernel32, "LoadLibraryW");
	log_info("Got address of LoadLibrary(): 0x%p", thread_callback);

	DWORD thread_id = 0;
	HANDLE thread = CreateRemoteThreadEx(process, NULL, 0, thread_callback, buffer, 0, 0, &thread_id);
	if (thread == NULL) {
		log_err("Failed to create thread: %ld", GetLastError());
		CloseHandle(process);
		return -1;
	}

	log_info("Waiting for thread to finish...");
	WaitForSingleObject(thread, INFINITE);
	log_info("Thread finished!");

	log_info("Cleaning up handles");
	CloseHandle(process);
	CloseHandle(thread);
	return 0;
}