lib/libkvm/kvm_getloadavg.c

   1 /*      $NetBSD: kvm_getloadavg.c,v 1.11 2012/03/21 10:10:36 matt Exp $ */
   2
   3 /*-
   4  * Copyright (c) 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char sccsid[] = "@(#)kvm_getloadavg.c    8.1 (Berkeley) 6/4/93";
  36 #else
  37 __RCSID("$NetBSD: kvm_getloadavg.c,v 1.11 2012/03/21 10:10:36 matt Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include <sys/param.h>
  42 #include <sys/time.h>
  43 #include <sys/resource.h>
  44 #include <sys/lwp.h>
  45 #include <sys/proc.h>
  46 #include <sys/sysctl.h>
  47 #include <uvm/uvm_param.h>
  48
  49 #include <db.h>
  50 #include <fcntl.h>
  51 #include <limits.h>
  52 #include <nlist.h>
  53 #include <kvm.h>
  54 #include <stdlib.h>
  55
  56 #include "kvm_private.h"
  57
  58 static struct nlist nl[] = {
  59         { .n_name = "_averunnable" },
  60 #define X_AVERUNNABLE   0
  61         { .n_name = "_fscale" },
  62 #define X_FSCALE        1
  63         { .n_name = "" },
  64 };
  65
  66 /*
  67  * kvm_getloadavg() -- Get system load averages, from live or dead kernels.
  68  *
  69  * Put `nelem' samples into `loadavg' array.
  70  * Return number of samples retrieved, or -1 on error.
  71  */
  72 int
  73 kvm_getloadavg(kvm_t *kd, double loadavg[], int nelem)
  74 {
  75         struct loadavg loadinfo;
  76         struct nlist *p;
  77         int fscale, i;
  78
  79         if (ISALIVE(kd))
  80                 return (getloadavg(loadavg, nelem));
  81
  82         if (kvm_nlist(kd, nl) != 0) {
  83                 for (p = nl; p->n_type != 0; ++p);
  84                 _kvm_err(kd, kd->program,
  85                     "%s: no such symbol", p->n_name);
  86                 return (-1);
  87         }
  88
  89         if (KREAD(kd, nl[X_AVERUNNABLE].n_value, &loadinfo)) {
  90                 _kvm_err(kd, kd->program, "can't read averunnable");
  91                 return (-1);
  92         }
  93
  94         /*
  95          * Old kernels have fscale separately; if not found assume
  96          * running new format.
  97          */
  98         if (!KREAD(kd, nl[X_FSCALE].n_value, &fscale))
  99                 loadinfo.fscale = fscale;
 100
 101         nelem = MIN(nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
 102         for (i = 0; i < nelem; i++)
 103                 loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
 104         return (nelem);
 105 }