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139 lines
3.9 KiB
C
139 lines
3.9 KiB
C
/*-
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* Copyright (c) 1980, 1992, 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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* 4. 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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#ifdef lint
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static const char sccsid[] = "@(#)fetch.c 8.1 (Berkeley) 6/6/93";
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#endif
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#include <sys/types.h>
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#include <sys/sysctl.h>
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#include <err.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include "systat.h"
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#include "extern.h"
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int
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kvm_ckread(void *a, void *b, int l)
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{
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if (kvm_read(kd, (u_long)a, b, l) != l) {
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if (verbose)
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error("error reading kmem at %p", a);
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return (0);
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}
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else
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return (1);
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}
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void getsysctl(const char *name, void *ptr, size_t len)
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{
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size_t nlen = len;
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if (sysctlbyname(name, ptr, &nlen, NULL, 0) != 0) {
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error("sysctl(%s...) failed: %s", name,
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strerror(errno));
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}
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if (nlen != len) {
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error("sysctl(%s...) expected %lu, got %lu", name,
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(unsigned long)len, (unsigned long)nlen);
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}
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}
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/*
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* Read sysctl data with variable size. Try some times (with increasing
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* buffers), fail if still too small.
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* This is needed sysctls with possibly raplidly increasing data sizes,
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* but imposes little overhead in the case of constant sizes.
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* Returns NULL on error, or a pointer to freshly malloc()'ed memory that holds
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* the requested data.
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* If szp is not NULL, the size of the returned data will be written into *szp.
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*/
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/* Some defines: Number of tries. */
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#define SD_NTRIES 10
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/* Percent of over-allocation (initial) */
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#define SD_MARGIN 10
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/*
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* Factor for over-allocation in percent (the margin is increased by this on
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* any failed try).
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*/
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#define SD_FACTOR 50
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/* Maximum supported MIB depth */
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#define SD_MAXMIB 16
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char *
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sysctl_dynread(const char *n, size_t *szp)
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{
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char *rv = NULL;
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int mib[SD_MAXMIB];
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size_t mibsz = SD_MAXMIB;
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size_t mrg = SD_MARGIN;
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size_t sz;
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int i;
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/* cache the MIB */
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if (sysctlnametomib(n, mib, &mibsz) == -1) {
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if (errno == ENOMEM) {
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error("XXX: SD_MAXMIB too small, please bump!");
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}
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return NULL;
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}
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for (i = 0; i < SD_NTRIES; i++) {
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/* get needed buffer size */
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if (sysctl(mib, mibsz, NULL, &sz, NULL, 0) == -1)
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break;
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sz += sz * mrg / 100;
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if ((rv = (char *)malloc(sz)) == NULL) {
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error("Out of memory!");
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return NULL;
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}
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if (sysctl(mib, mibsz, rv, &sz, NULL, 0) == -1) {
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free(rv);
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rv = NULL;
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if (errno == ENOMEM) {
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mrg += mrg * SD_FACTOR / 100;
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} else
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break;
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} else {
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/* success */
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if (szp != NULL)
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*szp = sz;
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break;
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}
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}
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return rv;
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}
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