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kvm_getloadavg.c revision 1.1 
      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)
     35 static 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 <db.h>
     46 #include <fcntl.h>
     47 #include <limits.h>
     48 #include <nlist.h>
     49 #include <kvm.h>
     50 
     51 #include "kvm_private.h"
     52 
     53 static struct nlist nl[] = {
     54 	{ "_averunnable" },
     55 #define	X_AVERUNNABLE	0
     56 	{ "_fscale" },
     57 #define	X_FSCALE	1
     58 	{ "" },
     59 };
     60 
     61 /*
     62  * kvm_getloadavg() -- Get system load averages, from live or dead kernels.
     63  *
     64  * Put `nelem' samples into `loadavg' array.
     65  * Return number of samples retrieved, or -1 on error.
     66  */
     67 int
     68 kvm_getloadavg(kd, loadavg, nelem)
     69 	kvm_t *kd;
     70 	double loadavg[];
     71 	int nelem;
     72 {
     73 	struct loadavg loadinfo;
     74 	struct nlist *p;
     75 	int fscale, i;
     76 
     77 	if (ISALIVE(kd))
     78 		return (getloadavg(loadavg, nelem));
     79 
     80 	if (kvm_nlist(kd, nl) != 0) {
     81 		for (p = nl; p->n_type != 0; ++p);
     82 		_kvm_err(kd, kd->program,
     83 		    "%s: no such symbol", p->n_name);
     84 		return (-1);
     85 	}
     86 
     87 #define KREAD(kd, addr, obj) \
     88 	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
     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