Re: Open master pty (/dev/ptmx) non blocking

[RVP <rvp%SDF.ORG@localhost>]

On Fri, 23 Sep 2022, David Holland wrote:

> While my inclination would be to make it work, until someone wants to
> figure out how to do that it seems straightforward to make O_NONBLOCK
> fail:
>
> Index: tty_ptm.c
> ===================================================================
> RCS file: /cvsroot/src/sys/kern/tty_ptm.c,v
> retrieving revision 1.43
> diff -u -p -r1.43 tty_ptm.c
> --- tty_ptm.c	29 Jun 2021 22:40:53 -0000	1.43
> +++ tty_ptm.c	23 Sep 2022 20:12:07 -0000
> @@ -338,6 +338,10 @@ ptmopen(dev_t dev, int flag, int mode, s
> 	dev_t ttydev;
> 	struct mount *mp;
>
> +	if (flag & O_NONBLOCK) {
> +		return EINVAL;
> +	}
> +

Or:
```
	if (flags & ~(O_RDWR | O_NOCTTY))
		return EINVAL;
```

-RVP