NetBSD/lib/libutil/getloadavg.c

94 lines
3.1 KiB
C

/*-
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getloadavg.c 6.2 (Berkeley) 6/29/90";
#endif /* LIBC_SCCS and not lint */
#include <sys/param.h>
#include <sys/types.h>
#include <sys/file.h>
#include <nlist.h>
static struct nlist nl[] = {
{ "_averunnable" },
#define X_AVERUNNABLE 0
{ "_fscale" },
#define X_FSCALE 1
{ "" },
};
/*
* getloadavg() -- Get system load averages.
*
* Put `nelem' samples into `loadavg' array.
* Return number of samples retrieved, or -1 on error.
*/
getloadavg(loadavg, nelem)
double loadavg[];
int nelem;
{
static int need_nlist = 1;
fixpt_t averunnable[3];
int fscale, kmemfd, i;
int alreadyopen;
if ((alreadyopen = kvm_openfiles(NULL, NULL, NULL)) == -1)
return (-1);
/*
* cache nlist
*/
if (need_nlist) {
if (kvm_nlist(nl) != 0)
goto bad;
need_nlist = 0;
}
if (kvm_read((off_t)nl[X_AVERUNNABLE].n_value, (char *)averunnable,
sizeof(averunnable)) != sizeof(averunnable))
goto bad;
if (kvm_read( (off_t)nl[X_FSCALE].n_value, (char *)&fscale,
sizeof(fscale)) != sizeof(fscale))
goto bad;
nelem = MIN(nelem, sizeof(averunnable) / sizeof(averunnable[0]));
for (i = 0; i < nelem; i++)
loadavg[i] = (double) averunnable[i] / fscale;
if (!alreadyopen)
kvm_close();
return (nelem);
bad:
if (!alreadyopen)
kvm_close();
return (-1);
}