Re: [PATCH 20/22] Implement shmctl(2)

[Richard Henderson]

On 9/8/23 18:59, Karim Taha wrote:
> Richard Henderson <richard.henderson@linaro.org> wrote:
>
> > On 8/19/23 02:48, Karim Taha wrote:
> > > +    switch (cmd) {
> > > +    case IPC_STAT:
> > > +    case IPC_SET:
> > > +        if (target_to_host_shmid_ds(&dsarg, buff)) {
> > > +            return -TARGET_EFAULT;
> > > +        }
> > > +        ret = get_errno(shmctl(shmid, cmd, &dsarg));
> > > +        if (host_to_target_shmid_ds(buff, &dsarg)) {
> > > +            return -TARGET_EFAULT;
> > > +        }
> > > +        break;
> >
> > IPC_STAT treats buff as output, IPC_SET treats buff as input,
> > so these cases can't be combined.
> >
> >
> > r~
>
> I think they can be combined:
> 1- we marshal the struct `buff` from target to host
> 2- call `shmctl`
> 3- marshal the results back.

No.  For IPC_SET, the target page need not be writable, as you assume here.


r~