[PATCH 4/7] msvcrt: Use trampoline for _beginthreadex().

[Piotr Caban]

Hi Arek,

On 5/4/21 1:49 PM, Arkadiusz Hiler wrote:
> +/*********************************************************************
> + *		_beginthreadex_trampoline
> + */
> +static DWORD CALLBACK _beginthreadex_trampoline(LPVOID arg)
> +{
> +    unsigned int retval;
> +    _beginthread_trampoline_t local_trampoline;
> +    thread_data_t *data = msvcrt_get_thread_data();
> +
> +    memcpy(&local_trampoline, arg, sizeof(local_trampoline));
> +    data->handle = local_trampoline.thread;
> +    free(arg);
> +
> +    retval = local_trampoline.start_address_ex(local_trampoline.arglist);
> +    _endthreadex(retval);
> +}
Compilation warning:
warning: no return statement in function returning non-void

>   /*********************************************************************
>    *		_beginthreadex (MSVCRT.@)
>    */
> @@ -161,12 +180,35 @@ uintptr_t CDECL _beginthreadex(
>     unsigned int initflag,   /* [in] Initial state of new thread (0 for running or CREATE_SUSPEND for suspended) */
>     unsigned int *thrdaddr)  /* [out] Points to a 32-bit variable that receives the thread identifier */
>   {
> +  _beginthread_trampoline_t* trampoline;
> +  HANDLE thread;
> +
>     TRACE("(%p, %d, %p, %p, %d, %p)\n", security, stack_size, start_address, arglist, initflag, thrdaddr);
>   
> -  /* FIXME */
> -  return (uintptr_t)CreateThread(security, stack_size,
> -				     start_address, arglist,
> -				     initflag, thrdaddr);
> +  if(!start_address) {
> +      *_errno() = EINVAL;
> +      return -1;
> +  }
The function returns 0 in ucrtbase on invalid argument. I didn't test 
what version it changes in.

Thanks,
Piotr