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      1 /*	$NetBSD: kvm_getloadavg.c,v 1.11 2012/03/21 10:10:36 matt 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. 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[] = "@(#)kvm_getloadavg.c	8.1 (Berkeley) 6/4/93";
     36 #else
     37 __RCSID("$NetBSD: kvm_getloadavg.c,v 1.11 2012/03/21 10:10:36 matt Exp $");
     38 #endif
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #include <sys/param.h>
     42 #include <sys/time.h>
     43 #include <sys/resource.h>
     44 #include <sys/lwp.h>
     45 #include <sys/proc.h>
     46 #include <sys/sysctl.h>
     47 #include <uvm/uvm_param.h>
     48 
     49 #include <db.h>
     50 #include <fcntl.h>
     51 #include <limits.h>
     52 #include <nlist.h>
     53 #include <kvm.h>
     54 #include <stdlib.h>
     55 
     56 #include "kvm_private.h"
     57 
     58 static struct nlist nl[] = {
     59 	{ .n_name = "_averunnable" },
     60 #define	X_AVERUNNABLE	0
     61 	{ .n_name = "_fscale" },
     62 #define	X_FSCALE	1
     63 	{ .n_name = "" },
     64 };
     65 
     66 /*
     67  * kvm_getloadavg() -- Get system load averages, from live or dead kernels.
     68  *
     69  * Put `nelem' samples into `loadavg' array.
     70  * Return number of samples retrieved, or -1 on error.
     71  */
     72 int
     73 kvm_getloadavg(kvm_t *kd, double loadavg[], int nelem)
     74 {
     75 	struct loadavg loadinfo;
     76 	struct nlist *p;
     77 	int fscale, i;
     78 
     79 	if (ISALIVE(kd))
     80 		return (getloadavg(loadavg, nelem));
     81 
     82 	if (kvm_nlist(kd, nl) != 0) {
     83 		for (p = nl; p->n_type != 0; ++p);
     84 		_kvm_err(kd, kd->program,
     85 		    "%s: no such symbol", p->n_name);
     86 		return (-1);
     87 	}
     88 
     89 	if (KREAD(kd, nl[X_AVERUNNABLE].n_value, &loadinfo)) {
     90 		_kvm_err(kd, kd->program, "can't read averunnable");
     91 		return (-1);
     92 	}
     93 
     94 	/*
     95 	 * Old kernels have fscale separately; if not found assume
     96 	 * running new format.
     97 	 */
     98 	if (!KREAD(kd, nl[X_FSCALE].n_value, &fscale))
     99 		loadinfo.fscale = fscale;
    100 
    101 	nelem = MIN(nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
    102 	for (i = 0; i < nelem; i++)
    103 		loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
    104 	return (nelem);
    105 }
    106