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      1 /*	$NetBSD: getloadavg.c,v 1.14 2012/03/13 21:13:36 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1989, 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[] = "@(#)getloadavg.c	8.1 (Berkeley) 6/4/93";
     36 #else
     37 __RCSID("$NetBSD: getloadavg.c,v 1.14 2012/03/13 21:13:36 christos Exp $");
     38 #endif
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #include "namespace.h"
     42 #include <sys/param.h>
     43 #include <sys/time.h>
     44 #include <sys/resource.h>
     45 #include <sys/sysctl.h>
     46 #include <uvm/uvm_param.h>
     47 
     48 #include <assert.h>
     49 #include <errno.h>
     50 #include <stdlib.h>
     51 
     52 #ifdef __weak_alias
     53 __weak_alias(getloadavg,_getloadavg)
     54 #endif
     55 
     56 /*
     57  * getloadavg() -- Get system load averages.
     58  *
     59  * Put `nelem' samples into `loadavg' array.
     60  * Return number of samples retrieved, or -1 on error.
     61  */
     62 int
     63 getloadavg(double loadavg[], int nelem)
     64 {
     65 	struct loadavg loadinfo;
     66 	static const int mib[] = { CTL_VM, VM_LOADAVG };
     67 	size_t size, i;
     68 
     69 	_DIAGASSERT(loadavg != NULL);
     70 	_DIAGASSERT(nelem >= 0);
     71 
     72 	size = sizeof(loadinfo);
     73 	if (sysctl(mib, (u_int)__arraycount(mib), &loadinfo, &size, NULL, 0)
     74 	    == -1)
     75 		return -1;
     76 
     77 	size = MIN((size_t)nelem, __arraycount(loadinfo.ldavg));
     78 	for (i = 0; i < size; i++)
     79 		loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
     80 	return nelem;
     81 }
     82