xref: /freebsd/lib/libc/gen/getloadavg.c (revision 42c159fe388a3765f69860c84183700af37aca8a)
1 /*-
2  * Copyright (c) 1989, 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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)getloadavg.c	8.1 (Berkeley) 6/4/93";
36 #endif /* LIBC_SCCS and not lint */
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include <sys/param.h>
41 #include <sys/time.h>
42 #include <sys/resource.h>
43 #include <sys/sysctl.h>
44 #include <vm/vm_param.h>
45 
46 #include <stdlib.h>
47 
48 /*
49  * getloadavg() -- Get system load averages.
50  *
51  * Put `nelem' samples into `loadavg' array.
52  * Return number of samples retrieved, or -1 on error.
53  */
54 int
55 getloadavg(loadavg, nelem)
56 	double loadavg[];
57 	int nelem;
58 {
59 	struct loadavg loadinfo;
60 	int i, mib[2];
61 	size_t size;
62 
63 	mib[0] = CTL_VM;
64 	mib[1] = VM_LOADAVG;
65 	size = sizeof(loadinfo);
66 	if (sysctl(mib, 2, &loadinfo, &size, NULL, 0) < 0)
67 		return (-1);
68 
69 	nelem = MIN(nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
70 	for (i = 0; i < nelem; i++)
71 		loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
72 	return (nelem);
73 }
74