[PATCH] An attempt to have an unlimitedly extendable sys_clone
xemul at openvz.org
Wed Jan 16 00:09:06 PST 2008
Daniel Hokka Zakrisson wrote:
> Pavel Emelyanov wrote:
>>>> +static struct long_clone_arg *get_long_clone_arg(int __user
>>>> + int size;
>>>> + struct long_clone_arg *carg;
>>>> + if (get_user(size, child_tidptr))
>>>> + return ERR_PTR(-EFAULT);
>>>> + if (size > sizeof(struct long_clone_arg))
>>>> + return ERR_PTR(-EINVAL);
>>> This means that software built against a newer kernel won't work on an
>>> older one. Surely that's not intended?
>> It is intended. If I ask an old kernel to clone the mq namespace, but
>> it doesn't support such, that I'd better like to get an -EINVAL error
>> rather than be silently held in an old global namespace.
> That rules out using the struct for things like child_tidptr, the desired
> pid for C/R, etc. I think the version Dave Hansen proposed would be
A new system call? Ok - what arguments should it take?
> better, or if it's really just for bits, use an array rather than a struct
> to make that obvious.
It's for anything you'd like to tell to clone(). In the nearest future - for
more bits to clone new namespaces. In the far future - for pid to create the
task with (for c/r jobs). In the the far-far future - for anything you will
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