Re: [PATCH v1 2/2] signal: add procfd_signal() syscall

[Andy Lutomirski <luto@kernel.org>]

On Mon, Nov 19, 2018 at 4:33 PM Christian Brauner <christian@brauner.io> wrote:
>
> On Mon, Nov 19, 2018 at 04:27:49PM -0800, Andy Lutomirski wrote:
> > On Mon, Nov 19, 2018 at 3:07 PM Tycho Andersen <tycho@tycho.ws> wrote:
> > > > These tools also care about ioctls. Adding a system call is a pain,
> > > > but the solution is to make adding system calls less of a pain, not to
> > > > permanently make the Linux ABI worse.
> > >
> > > For user-defined values of "worse" :)
> > >
> >
> > I tend to agree with Tycho here.  But I'm wondering if it might be
> > worth considering a better ioctl.
> >
> > /me dons flame-proof hat
> >
> > We could do:
> >
> > long better_ioctl(int fd, u32 nr, const void *inbuf, size_t inlen,
> > const void *outbuf, size_t outlen);
>
> I'm the writer of this patch so take this with a grain of salt.
> I think it is a bad idea to stop this patch and force us to introduce a
> new type of ioctl().

I agree completely.

> An ioctl() is also not easy to use for this task because we want to add
> a siginfo_t argument which I actually think provides value and makes
> this interface more useful.
>

You could always have a struct procfd_kill and pass a pointer to
*that*.  But sure, it's ugly.