Re: pidfile_lock(3)

[Roy Marples <roy%marples.name@localhost>]

Lets go back to the original question.

On 20/03/2016 09:26, Michael van Elst wrote:
> roy%marples.name@localhost (Roy Marples) writes:
> 
>> So I've created pidfile_lock (patch attached) to address these problems.
> 
> Does it work on NFS root?

After taking on board what everyone has said, my considered answer is thus:

If it doesn't work on NFS and you care so much, please spend your time
fixing NFS rather than telling me about it (someone who doesn't care
about NFS) on an email thread that will soon be lost to the void.
As a first step,  I heartily recommend documenting any locking issues in
our man pages as a first step.

Now if NFS is not fixable (NFS is quite old so likely no-one here cares
enough to actually fix it but they surely care enough to moan about it)
I suggest we either not recommend /var/run on NFS and use tmpfs (as
Joerg suggested), have a daemon to handle it for us (as James suggested)
or give up on pidfiles completely * as I don't accept the possibility to
store and fetch inaccurate information.

* By this i mean in the application. pidfiles could be maintained by any
future rc(8) replacement. It can even handle processes crashing and
clean up the pidifle quite quickly by monitoring the pid in kqueue using
EVFILT_PROC.

Roy