lib/libkvm/kvm_getloadavg.c

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