#include <Windows.h>
#include <ktmw32.h>
#include <sddl.h>

#include <cstdio>

#pragma comment(lib, "ktmw32")

int main() {
  LSTATUS st;

  //
  // Create a transaction.
  //

  HANDLE hTrans = CreateTransaction(NULL, NULL, 0, 0, 0, 0, NULL);
  if (hTrans == INVALID_HANDLE_VALUE) {
    printf("CreateTransaction failed with error %u\n", GetLastError());
    return 1;
  }

  //
  // Create a HKLM\Software\Test key within the transaction.
  //

  HKEY hTestKey;
  st = RegCreateKeyTransactedA(HKEY_LOCAL_MACHINE,
                               "Software\\Test",
                               0,
                               NULL,
                               REG_OPTION_VOLATILE,
                               KEY_ALL_ACCESS,
                               NULL,
                               &hTestKey,
                               NULL,
                               hTrans,
                               NULL);

  if (st != ERROR_SUCCESS) {
    printf("RegCreateKeyTransactedA failed with error %d\n", st);
    return 1;
  }

  //
  // Set a new value in the transactionally created key.
  //

  st = RegSetValueExA(hTestKey, "Value", 0, REG_SZ, (const BYTE*)"SECRET", 6);

  if (st != ERROR_SUCCESS) {
    printf("RegSetValueExA failed with error %d\n", st);
    return 1;
  }

  //
  // Create another sub key.
  //

  HKEY hSubKey;
  st = RegCreateKeyTransactedA(hTestKey,
                               "SubKey",
                               0,
                               NULL,
                               REG_OPTION_VOLATILE,
                               KEY_ALL_ACCESS,
                               NULL,
                               &hSubKey,
                               NULL,
                               hTrans,
                               NULL);

  if (st != ERROR_SUCCESS) {
    printf("RegCreateKeyTransactedA failed with error %d\n", st);
    return 1;
  }

  //
  // Set a custom security descriptor on the parent key to only allow access to
  // administrators.
  //

  PSECURITY_DESCRIPTOR lpSecurityDescriptor;

  CONST WCHAR* szSD = L"D:PAI(A;CI;KA;;;BA)"; // Allow KEY_ALL_ACCESS for Administrators.

  if (!ConvertStringSecurityDescriptorToSecurityDescriptorW(szSD,
                                                            SDDL_REVISION_1,
                                                            &lpSecurityDescriptor,
                                                            NULL)) {
    printf("ConvertStringSecurityDescriptorToSecurityDescriptorW failed with "
           "error %u\n", GetLastError());
    return 1;
  }

  st = RegSetKeySecurity(hTestKey, DACL_SECURITY_INFORMATION, lpSecurityDescriptor);

  if (st != ERROR_SUCCESS) {
    printf("RegSetKeySecurity failed with error %d\n", st);
    return 1;
  }

  //
  // Commit the transaction.
  //

  if (!CommitTransaction(hTrans)) {
    printf("CommitTransaction failed with error %u\n", GetLastError());
    return 1;
  }

  RegCloseKey(hSubKey);
  RegCloseKey(hTestKey);
  CloseHandle(hTrans);

  return 0;
}