xref: /netbsd-src/lib/libc/gen/getloadavg.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: getloadavg.c,v 1.13 2003/08/07 16:42:50 agc 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 1.13 2003/08/07 16:42:50 agc 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 }
85