Re: runsv and process groups

[Charlie Brady <charlieb-smarden-supervise@budge.apana.org.au>]

On Thu, 26 Aug 2004, Gerrit Pape wrote:

> On Thu, Aug 26, 2004 at 01:05:13PM -0400, Charlie Brady wrote:
> > On 26 Aug 2004, Clemens Fischer wrote:
> > > > it be easier for (nearly) everyone if runsv did it?
> > > for me this is about choice,
> > I don't see how your freedom would be curtailed if runsv's behaviour was a 
> > little different.
> Once setsid() is called there's no way back.

Sure, but if the process is still running root, it can send a signal to
its parent's process group.

> > I'm still curious about Gerrit's opinion. Is there a good reason why runsv 
> > doesn't put each run script in a new process group? [Other than the 
> > obvious reason that that would be different behavior to daemontools].
> 
> Hm, I'm not sure yet.  What do you think about runsvdir running runsv in
> a new process group, and not runsv the run script?

That'd satisfy my concern, which is that a buggy run script or daemon can
easily take down the whole system. That's certainly not the resiliency
which people are looking for when they use supervise/runit. Or at least, 
which I'm looking for.

I have more than an academic interest in this issue, since I've been 
bitten by it in the past.

---
Charlie