1 /* $OpenBSD: getloadavg.c,v 1.9 2020/10/12 22:08:33 deraadt Exp $ */
2 /*-
3 * Copyright (c) 1989, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <sys/time.h>
32 #include <sys/resource.h>
33 #include <sys/sysctl.h>
34
35 #include <stdlib.h>
36
37 #define MINIMUM(a, b) (((a) < (b)) ? (a) : (b))
38
39 /*
40 * getloadavg() -- Get system load averages.
41 *
42 * Put `nelem' samples into `loadavg' array.
43 * Return number of samples retrieved, or -1 on error.
44 */
45 int
getloadavg(double loadavg[],int nelem)46 getloadavg(double loadavg[], int nelem)
47 {
48 struct loadavg loadinfo;
49 const int mib[2] = { CTL_VM, VM_LOADAVG };
50 int i;
51 size_t size;
52
53 size = sizeof(loadinfo);
54 if (sysctl(mib, 2, &loadinfo, &size, NULL, 0) == -1)
55 return (-1);
56
57 nelem = MINIMUM(nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
58 for (i = 0; i < nelem; i++)
59 loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
60 return (nelem);
61 }
62