freebsd-dev/lib/libkvm/kvm_getloadavg.c
Peter Wemm c4a7cdb3b6 Use kldsym(2) to lookup symbol values. This avoids the kvm_mkdb juggling
and is module aware.  Yes, this means that kvm_nlist(3) will find symbols
in loaded modules.  The emulation of the nlist struct is pretty crude but
seems to work well enough for all the users in the tree that I found.
1999-12-27 07:14:58 +00:00

111 lines
3.5 KiB
C

/*-
* Copyright (c) 1993
* 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)
#if 0
static char sccsid[] = "@(#)kvm_getloadavg.c 8.1 (Berkeley) 6/4/93";
#else
static const char rcsid[] =
"$FreeBSD$";
#endif
#endif /* LIBC_SCCS and not lint */
#include <sys/param.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <vm/vm_param.h>
#include <stdlib.h>
#include <fcntl.h>
#include <limits.h>
#include <nlist.h>
#include <kvm.h>
#include "kvm_private.h"
static struct nlist nl[] = {
{ "_averunnable" },
#define X_AVERUNNABLE 0
{ "_fscale" },
#define X_FSCALE 1
{ "" },
};
/*
* kvm_getloadavg() -- Get system load averages, from live or dead kernels.
*
* Put `nelem' samples into `loadavg' array.
* Return number of samples retrieved, or -1 on error.
*/
int
kvm_getloadavg(kd, loadavg, nelem)
kvm_t *kd;
double loadavg[];
int nelem;
{
struct loadavg loadinfo;
struct nlist *p;
int fscale, i;
if (ISALIVE(kd))
return (getloadavg(loadavg, nelem));
if (kvm_nlist(kd, nl) != 0) {
for (p = nl; p->n_type != 0; ++p);
_kvm_err(kd, kd->program,
"%s: no such symbol", p->n_name);
return (-1);
}
#define KREAD(kd, addr, obj) \
(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
if (KREAD(kd, nl[X_AVERUNNABLE].n_value, &loadinfo)) {
_kvm_err(kd, kd->program, "can't read averunnable");
return (-1);
}
/*
* Old kernels have fscale separately; if not found assume
* running new format.
*/
if (!KREAD(kd, nl[X_FSCALE].n_value, &fscale))
loadinfo.fscale = fscale;
nelem = MIN(nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
for (i = 0; i < nelem; i++)
loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
return (nelem);
}