Re: unhare() interface design questions and man page

From: Linus Torvalds
Date: Wed Mar 01 2006 - 23:02:01 EST




On Thu, 2 Mar 2006, Michael Kerrisk wrote:
> > >>>>>
> > >>>>> That is, CLONE_FS, CLONE_FILES, and CLONE_VM *reverse* the
> > >>>>> effects of the clone() flags of the same name, but CLONE_NEWNS
> > >>>>> *has the same meaning* as the clone() flag of the same name.

Well, if this is the only problem, who cares? CLONE_NEWNS itself is
actually a reversal of clone flags: unlike the others, that tell to
_share_ things that normally aren't shared across a fork(), CLONE_NEWNS
does the opposite: it asks to unshare something that normally is shared.

So the fact that it then acts not as a reversal when doing "unshare()" is
actually consistent with the fact that it's a already a "unshare" event
for clone() itself.

> Do you have any further response on this point?
> (There was none in your last message?)

I personally don't think it's worth makign UNSHARE_NEWNS just because it's
a flag that acts differently from the other CLONE_xxx flags.

As to whether allow or not allow unknown unshare() flags, I don't think
it's a huge deal either way. Right now we don't check the flags to
"clone()" either, I think.

Linus
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