Is fork() hook ever possible?
attilio at freebsd.org
Tue Sep 16 14:54:01 UTC 2008
2008/9/16, Andrey Chernov <ache at nagual.pp.ru>:
> On Tue, Sep 16, 2008 at 03:38:16PM +0100, Bob Bishop wrote:
> > Hi,
> > On 16 Sep 2008, at 15:03, Andrey Chernov wrote:
> > > I need some sort of fork() hook to detect that pid is changed to re-
> > > stir
> > > ar4random() after that (in the child), simple flag variable with
> > > child's pid is needed.
> > >
> > > Currently OpenBSD does almost that checking getpid() every time
> > > arc4random() called, but it is very slow way to use getpid() syscall
> > > repeatedly, about 12-15 times slower than just arc4random() without
> > > getpid().
> > >
> > > Any ideas?
> > How about something hacky using mmap()/minherit()?
> Could you please provide working low cost example to detect that we are in
> the child (pid changed or something else)? Calling getpid() as OpenBSD
> does definitely is very high cost. :(
An idea would be to implement a shared page between process and system
which exports such informations.
I'm sure we have a SoC project (2007) implementing this and perforce
branches for it, I'm just not sure how far it did end.
Peace can only be achieved by understanding - A. Einstein
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