Fix kvm_getloadavg() to work correctly on vmcores for modern kernel versions. The kernels no longer include the `_fscale` symbol causing the kvm_nlist() invocation to fail. The code seemed to already assume that `_fscale` could be missing but the early kvm_nlist() result check has caused the function to fail if any symbol were missing. Modify it to only treat `_averunnable` as obligatory, and handle missing `_fscale` gracefully. Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D32884
102 lines
3.2 KiB
C
102 lines
3.2 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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__SCCSID("@(#)kvm_getloadavg.c 8.1 (Berkeley) 6/4/93");
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#include <sys/param.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <stdlib.h>
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#include <limits.h>
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#include <nlist.h>
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#include <kvm.h>
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#include "kvm_private.h"
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static struct nlist nl[] = {
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{ .n_name = "_averunnable" },
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#define X_AVERUNNABLE 0
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{ .n_name = "_fscale" },
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#define X_FSCALE 1
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{ .n_name = "" },
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};
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/*
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* kvm_getloadavg() -- Get system load averages, from live or dead kernels.
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*
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* Put `nelem' samples into `loadavg' array.
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* Return number of samples retrieved, or -1 on error.
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*/
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int
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kvm_getloadavg(kvm_t *kd, double loadavg[], int nelem)
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{
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struct loadavg loadinfo;
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int fscale, i;
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if (ISALIVE(kd))
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return (getloadavg(loadavg, nelem));
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if (!kd->arch->ka_native(kd)) {
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_kvm_err(kd, kd->program,
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"cannot read loadavg from non-native core");
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return (-1);
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}
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if (kvm_nlist(kd, nl) != 0 && nl[X_AVERUNNABLE].n_type == 0) {
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_kvm_err(kd, kd->program,
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"%s: no such symbol", nl[X_AVERUNNABLE].n_name);
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return (-1);
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}
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#define KREAD(kd, addr, obj) \
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(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
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if (KREAD(kd, nl[X_AVERUNNABLE].n_value, &loadinfo)) {
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_kvm_err(kd, kd->program, "can't read averunnable");
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return (-1);
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}
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/*
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* Old kernels have fscale separately; if not found assume
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* running new format.
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*/
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if (nl[X_FSCALE].n_type != 0 &&
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!KREAD(kd, nl[X_FSCALE].n_value, &fscale))
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loadinfo.fscale = fscale;
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nelem = MIN(nelem, (int)(sizeof(loadinfo.ldavg) / sizeof(fixpt_t)));
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for (i = 0; i < nelem; i++)
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loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
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return (nelem);
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}
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