lib/libc/gen/getloadavg.c

   1 /*      $NetBSD: getloadavg.c,v 1.12 2002/11/11 16:58:42 thorpej Exp $  */
   2
   3 /*-
   4  * Copyright (c) 1989, 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[] = "@(#)getloadavg.c        8.1 (Berkeley) 6/4/93";
  36 #else
  37 __RCSID("$NetBSD: getloadavg.c,v 1.12 2002/11/11 16:58:42 thorpej Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42 #include <sys/param.h>
  43 #include <sys/time.h>
  44 #include <sys/resource.h>
  45 #include <sys/sysctl.h>
  46 #include <uvm/uvm_param.h>
  47
  48 #include <assert.h>
  49 #include <errno.h>
  50 #include <stdlib.h>
  51
  52 #ifdef __weak_alias
  53 __weak_alias(getloadavg,_getloadavg)
  54 #endif
  55
  56 /*
  57  * getloadavg() -- Get system load averages.
  58  *
  59  * Put `nelem' samples into `loadavg' array.
  60  * Return number of samples retrieved, or -1 on error.
  61  */
  62 int
  63 getloadavg(loadavg, nelem)
  64         double loadavg[];
  65         int nelem;
  66 {
  67         struct loadavg loadinfo;
  68         int i, mib[2];
  69         size_t size;
  70
  71         _DIAGASSERT(loadavg != NULL);
  72         _DIAGASSERT(nelem >= 0);
  73
  74         mib[0] = CTL_VM;
  75         mib[1] = VM_LOADAVG;
  76         size = sizeof(loadinfo);
  77         if (sysctl(mib, 2, &loadinfo, &size, NULL, 0) < 0)
  78                 return (-1);
  79
  80         nelem = MIN((size_t) nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
  81         for (i = 0; i < nelem; i++)
  82                 loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
  83         return (nelem);
  84 }