Re: [musl] [PATCH] add check for pthread_attr_setschedparam().

[Rich Felker <dalias@libc.org>]

On Tue, Dec 24, 2024 at 10:03:01AM +0800, yan.li.cn@windriver.com wrote:
> From: Yan Li <yan.li.cn@windriver.com>
> 
> ---
>  src/thread/pthread_attr_setschedparam.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>  mode change 100644 => 100755 src/thread/pthread_attr_setschedparam.c
> 
> diff --git a/src/thread/pthread_attr_setschedparam.c b/src/thread/pthread_attr_setschedparam.c
> old mode 100644
> new mode 100755
> index d4c1204f..4e28415e
> --- a/src/thread/pthread_attr_setschedparam.c
> +++ b/src/thread/pthread_attr_setschedparam.c
> @@ -2,6 +2,13 @@
>  
>  int pthread_attr_setschedparam(pthread_attr_t *restrict a, const struct sched_param *restrict param)
>  {
> -	a->_a_prio = param->sched_priority;
> -	return 0;
> +    int min = sched_get_priority_min (a->_a_policy);
> +    int max = sched_get_priority_max (a->_a_policy);
> +
> +    if (min < 0 || max < 0 || param->sched_priority < min || param->sched_priority > max){
> +        return EINVAL;
> +    }
> +
> +    a->_a_prio = param->sched_priority;
> +    return 0;
>  }
> -- 
> 2.34.1

I don't see a good motivation for this change. The error conditions
are MAY FAIL, not SHALL FAIL, and checking for them incurs two useless
syscalls on every call to a function that's otherwise syscall-free.

Rich