xref: /freebsd/lib/libc/gen/getloadavg.c (revision cab6a39d7b343596a5823e65c0f7b426551ec22d)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
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 __SCCSID("@(#)getloadavg.c	8.1 (Berkeley) 6/4/93");
34 __FBSDID("$FreeBSD$");
35 
36 #include <sys/param.h>
37 #include <sys/time.h>
38 #include <sys/resource.h>
39 #include <sys/sysctl.h>
40 #include <vm/vm_param.h>
41 
42 #include <stdlib.h>
43 
44 /*
45  * getloadavg() -- Get system load averages.
46  *
47  * Put `nelem' samples into `loadavg' array.
48  * Return number of samples retrieved, or -1 on error.
49  */
50 int
51 getloadavg(double loadavg[], int nelem)
52 {
53 	struct loadavg loadinfo;
54 	int i, mib[2];
55 	size_t size;
56 
57 	mib[0] = CTL_VM;
58 	mib[1] = VM_LOADAVG;
59 	size = sizeof(loadinfo);
60 	if (sysctl(mib, 2, &loadinfo, &size, NULL, 0) < 0)
61 		return (-1);
62 
63 	nelem = MIN(nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
64 	for (i = 0; i < nelem; i++)
65 		loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
66 	return (nelem);
67 }
68