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kvm_getloadavg.c revision 1.2 
      1 /*	$NetBSD: kvm_getloadavg.c,v 1.2 1996/03/18 22:33:31 thorpej Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #if defined(LIBC_SCCS) && !defined(lint)
     37 #if 0
     38 static char sccsid[] = "@(#)kvm_getloadavg.c	8.1 (Berkeley) 6/4/93";
     39 #else
     40 static char *rcsid = "$NetBSD: kvm_getloadavg.c,v 1.2 1996/03/18 22:33:31 thorpej Exp $";
     41 #endif
     42 #endif /* LIBC_SCCS and not lint */
     43 
     44 #include <sys/param.h>
     45 #include <sys/time.h>
     46 #include <sys/resource.h>
     47 #include <sys/proc.h>
     48 #include <sys/sysctl.h>
     49 #include <vm/vm_param.h>
     50 
     51 #include <db.h>
     52 #include <fcntl.h>
     53 #include <limits.h>
     54 #include <nlist.h>
     55 #include <kvm.h>
     56 
     57 #include "kvm_private.h"
     58 
     59 static struct nlist nl[] = {
     60 	{ "_averunnable" },
     61 #define	X_AVERUNNABLE	0
     62 	{ "_fscale" },
     63 #define	X_FSCALE	1
     64 	{ "" },
     65 };
     66 
     67 /*
     68  * kvm_getloadavg() -- Get system load averages, from live or dead kernels.
     69  *
     70  * Put `nelem' samples into `loadavg' array.
     71  * Return number of samples retrieved, or -1 on error.
     72  */
     73 int
     74 kvm_getloadavg(kd, loadavg, nelem)
     75 	kvm_t *kd;
     76 	double loadavg[];
     77 	int nelem;
     78 {
     79 	struct loadavg loadinfo;
     80 	struct nlist *p;
     81 	int fscale, i;
     82 
     83 	if (ISALIVE(kd))
     84 		return (getloadavg(loadavg, nelem));
     85 
     86 	if (kvm_nlist(kd, nl) != 0) {
     87 		for (p = nl; p->n_type != 0; ++p);
     88 		_kvm_err(kd, kd->program,
     89 		    "%s: no such symbol", p->n_name);
     90 		return (-1);
     91 	}
     92 
     93 #define KREAD(kd, addr, obj) \
     94 	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
     95 	if (KREAD(kd, nl[X_AVERUNNABLE].n_value, &loadinfo)) {
     96 		_kvm_err(kd, kd->program, "can't read averunnable");
     97 		return (-1);
     98 	}
     99 
    100 	/*
    101 	 * Old kernels have fscale separately; if not found assume
    102 	 * running new format.
    103 	 */
    104 	if (!KREAD(kd, nl[X_FSCALE].n_value, &fscale))
    105 		loadinfo.fscale = fscale;
    106 
    107 	nelem = MIN(nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
    108 	for (i = 0; i < nelem; i++)
    109 		loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
    110 	return (nelem);
    111 }
    112