[HACKERS] semaphore usage "port based"?

[Andrew Thompson]

On Mon, Apr 03, 2006 at 01:23:59AM -0300, Marc G. Fournier wrote:
> 
> taking it off of pgsql-hackers, so that we don't annoy them unnecessarily 
> ...
> 
> 'k, looking at the code, not that most of it doesn't go over my head ... 
> but ...
> 
> in kern/kern_jail.c, I can see the prison_check() call ... wouldn't one 
> want to make the change a bit further up?  say in kern_prot.c?  wouldn't 
> you want to change just cr_cansignal() to allow *just* for 'case 0', when 
> someone is just checking to see if a process is already running?  I 
> wouldn't want to be able to SIGKILL the process from a different jail, 
> mind you ... maybe move the check for SIG0 to just before the 
> prison_check, since, unless I'm missing something, other then determining 
> that a process is, in fact, running, SIG0 is a benign signal?
> 

I think the suggestion was to make this EPERM rather than ESRCH to make
postgres a bit happier, not remove the check entirely. Im not familiar
with that part of the kernel at all, so I cant say what the consequences
will be apart from the obvious information leak.


Andrew