kvm_getloadavg.c revision 17141 
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 * 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)
35static char sccsid[] = "@(#)kvm_getloadavg.c	8.1 (Berkeley) 6/4/93";
36#endif /* LIBC_SCCS and not lint */
37
38#include <sys/param.h>
39#include <sys/time.h>
40#include <sys/resource.h>
41#include <sys/proc.h>
42#include <sys/sysctl.h>
43#include <vm/vm_param.h>
44
45#include <stdlib.h>
46#include <db.h>
47#include <fcntl.h>
48#include <limits.h>
49#include <nlist.h>
50#include <kvm.h>
51
52#include "kvm_private.h"
53
54static struct nlist nl[] = {
55	{ "_averunnable" },
56#define	X_AVERUNNABLE	0
57	{ "_fscale" },
58#define	X_FSCALE	1
59	{ "" },
60};
61
62/*
63 * kvm_getloadavg() -- Get system load averages, from live or dead kernels.
64 *
65 * Put `nelem' samples into `loadavg' array.
66 * Return number of samples retrieved, or -1 on error.
67 */
68int
69kvm_getloadavg(kd, loadavg, nelem)
70	kvm_t *kd;
71	double loadavg[];
72	int nelem;
73{
74	struct loadavg loadinfo;
75	struct nlist *p;
76	int fscale, i;
77
78	if (ISALIVE(kd))
79		return (getloadavg(loadavg, nelem));
80
81	if (kvm_nlist(kd, nl) != 0) {
82		for (p = nl; p->n_type != 0; ++p);
83		_kvm_err(kd, kd->program,
84		    "%s: no such symbol", p->n_name);
85		return (-1);
86	}
87
88#define KREAD(kd, addr, obj) \
89	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
90	if (KREAD(kd, nl[X_AVERUNNABLE].n_value, &loadinfo)) {
91		_kvm_err(kd, kd->program, "can't read averunnable");
92		return (-1);
93	}
94
95	/*
96	 * Old kernels have fscale separately; if not found assume
97	 * running new format.
98	 */
99	if (!KREAD(kd, nl[X_FSCALE].n_value, &fscale))
100		loadinfo.fscale = fscale;
101
102	nelem = MIN(nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
103	for (i = 0; i < nelem; i++)
104		loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
105	return (nelem);
106}
107