1/*-
2 * Copyright (c) 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 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: releng/10.3/lib/libkvm/kvm_getloadavg.c 217744 2011-01-23 11:08:28Z uqs $");
32
33#if defined(LIBC_SCCS) && !defined(lint)
34#if 0
35static char sccsid[] = "@(#)kvm_getloadavg.c	8.1 (Berkeley) 6/4/93";
36#endif
37#endif /* LIBC_SCCS and not lint */
38
39#include <sys/param.h>
40#include <sys/time.h>
41#include <sys/resource.h>
42
43#include <stdlib.h>
44#include <limits.h>
45#include <nlist.h>
46#include <kvm.h>
47
48#include "kvm_private.h"
49
50static struct nlist nl[] = {
51	{ .n_name = "_averunnable" },
52#define	X_AVERUNNABLE	0
53	{ .n_name = "_fscale" },
54#define	X_FSCALE	1
55	{ .n_name = "" },
56};
57
58/*
59 * kvm_getloadavg() -- Get system load averages, from live or dead kernels.
60 *
61 * Put `nelem' samples into `loadavg' array.
62 * Return number of samples retrieved, or -1 on error.
63 */
64int
65kvm_getloadavg(kvm_t *kd, double loadavg[], int nelem)
66{
67	struct loadavg loadinfo;
68	struct nlist *p;
69	int fscale, i;
70
71	if (ISALIVE(kd))
72		return (getloadavg(loadavg, nelem));
73
74	if (kvm_nlist(kd, nl) != 0) {
75		for (p = nl; p->n_type != 0; ++p);
76		_kvm_err(kd, kd->program,
77		    "%s: no such symbol", p->n_name);
78		return (-1);
79	}
80
81#define KREAD(kd, addr, obj) \
82	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
83	if (KREAD(kd, nl[X_AVERUNNABLE].n_value, &loadinfo)) {
84		_kvm_err(kd, kd->program, "can't read averunnable");
85		return (-1);
86	}
87
88	/*
89	 * Old kernels have fscale separately; if not found assume
90	 * running new format.
91	 */
92	if (!KREAD(kd, nl[X_FSCALE].n_value, &fscale))
93		loadinfo.fscale = fscale;
94
95	nelem = MIN(nelem, (int)(sizeof(loadinfo.ldavg) / sizeof(fixpt_t)));
96	for (i = 0; i < nelem; i++)
97		loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
98	return (nelem);
99}
100