Re: Problems reading process vitals on FreeBSD when the monitored process is swapped out

[Rory Toma]

I suspect the fact that you can't get this info if you aren't root is 
security-related.

I'll look into it. I'm working on snmp stuff right now.

BTW, did we ever get a base OID?

On 2004-02-26 05:08:17 -0800 Christian Hopp 
<address@hidden> wrote:

> On Thu, 26 Feb 2004, Ralf Hack wrote:
>
> Hello!
>
> > I monitor an ssh tunnel and get the following message after several
> > hours. It appears that kvm_read fails reading the memory size once
> > the process is swapped out on the monitoring server (STAT
> > += W). Once I active the monitored process by simply using the
> > session, the problem disappears. Sorry, I do not know enough about
> > FreeBSD programming to offer a fix for this.
>
> (...)
>
> > I could track down the problem using gdb to line 376 in 
> > sysdep_FREEBSD.c
> >
> > Breakpoint 3, get_process_info_sysdep (p=0x808f4c0)
> >      at process/sysdep_FREEBSD.c:376
> > 376         return FALSE;
> > (gdb) c
> >
> >
> >    /* ----------------------------- MEMORY 
> > --------------------------------*/
> >    /* Got it from libgtop/sysdep/freebsd/procmem.c */
> >
> >    if (kvm_read (kvm_handle,
> > #if (__FreeBSD_version > 500000)
> >                  (unsigned long) &pinfo->ki_addr->p_limit,
> > #else
> >                  (unsigned long) pinfo [0].kp_proc.p_limit,
> > #endif
> >                  (char *) &plimit, sizeof (plimit)) != sizeof 
> > (plimit)) {
> >
> >      return FALSE;
> >
> >    }
>
> Yep, it has to be there!  It's really tricky.  If this kvm_read call
> fails, too less data is transmitted from the kernel (see man page or
> other implementations).  I am hesitant to guess the amount of memory
> at that point (e.g. 0), but it is the only solution I see at that
> point.
>
> I would love to have more docs about freebsd and kvm, but I haven't
> googled anything useful yet.  I have cursed about all this already a
> lot!
>
> Christian