[Devel] [RFC PATCH 0/5] Resend -v2 - Use procfs to change a syscall behavior
Eric W. Biederman
ebiederm at xmission.com
Wed Jul 9 19:14:37 PDT 2008
Alexey Dobriyan <adobriyan at gmail.com> writes:
> In case of ->did_exec the only clean interface I see is:
> tsk->did_exec = !!tsk_img->did_exec;
> It would be pretty silly to wrap this one line in a system call (two
> actually -- one in, one out), since you're going to restore some more
> fields of such variety anyway (like ->pdeath_signal).
There I agree the granularity seems small enough to be a major pain
for the implementation.
> Given the diversity of kernel internal data structures and all sorts of
> links between them, the only system call suitable is ioctl(2), not all
> this zoo of system calls proposed. They are all extendable and without
> rules, but ioctl(2) is also without rules.
At least for processes my gut reaction is to look at binary formats
and coredumps. Something with at least that large of a granularity seems
to make most sense.
> This is all said in assumption that serializing kernel-internal data for
> checkpoint/restart to userspace is acceptable for mainline.
> I don't think it is.
I don't believe that serializing kernel-internal data is acceptable
for mainline. I believe that serializing user-visible data is acceptable.
Note: user-visible data does not mean user-manipulatable data.
On a socket you may not save the skbs but you can save the pending packets
for example. Assuming the transition cost is not too high.
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