/*      $NetBSD: kvm_getloadavg.c,v 1.11 2012/03/21 10:10:36 matt Exp $ */

/*-
* Copyright (c) 1993
*      The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)kvm_getloadavg.c    8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: kvm_getloadavg.c,v 1.11 2012/03/21 10:10:36 matt Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/lwp.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <uvm/uvm_param.h>

#include <db.h>
#include <fcntl.h>
#include <limits.h>
#include <nlist.h>
#include <kvm.h>
#include <stdlib.h>

#include "kvm_private.h"

static struct nlist nl[] = {
       { .n_name = "_averunnable" },
#define X_AVERUNNABLE   0
       { .n_name = "_fscale" },
#define X_FSCALE        1
       { .n_name = "" },
};

/*
* kvm_getloadavg() -- Get system load averages, from live or dead kernels.
*
* Put `nelem' samples into `loadavg' array.
* Return number of samples retrieved, or -1 on error.
*/
int
kvm_getloadavg(kvm_t *kd, double loadavg[], int nelem)
{
       struct loadavg loadinfo;
       struct nlist *p;
       int fscale, i;

       if (ISALIVE(kd))
               return (getloadavg(loadavg, nelem));

       if (kvm_nlist(kd, nl) != 0) {
               for (p = nl; p->n_type != 0; ++p);
               _kvm_err(kd, kd->program,
                   "%s: no such symbol", p->n_name);
               return (-1);
       }

       if (KREAD(kd, nl[X_AVERUNNABLE].n_value, &loadinfo)) {
               _kvm_err(kd, kd->program, "can't read averunnable");
               return (-1);
       }

       /*
        * Old kernels have fscale separately; if not found assume
        * running new format.
        */
       if (!KREAD(kd, nl[X_FSCALE].n_value, &fscale))
               loadinfo.fscale = fscale;

       nelem = MIN(nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
       for (i = 0; i < nelem; i++)
               loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
       return (nelem);
}