/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1980, 1992, 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. 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.
*/
#include <sys/types.h>
#include <sys/sysctl.h>
#include <err.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "systat.h"
#include "extern.h"
int
kvm_ckread(void *a, void *b, int l)
{
if (kvm_read(kd, (u_long)a, b, l) != l) {
if (verbose)
error("error reading kmem at %p", a);
return (0);
}
else
return (1);
}
void
getsysctl(const char *name, void *ptr, size_t len)
{
size_t nlen = len;
if (sysctlbyname(name, ptr, &nlen, NULL, 0) != 0) {
error("sysctl(%s...) failed: %s", name,
strerror(errno));
}
if (nlen != len) {
error("sysctl(%s...) expected %zu, got %zu", name, len, nlen);
}
}
/*
* Read sysctl data with variable size. Try some times (with increasing
* buffers), fail if still too small.
* This is needed sysctls with possibly raplidly increasing data sizes,
* but imposes little overhead in the case of constant sizes.
* Returns NULL on error, or a pointer to freshly malloc()'ed memory that holds
* the requested data.
* If szp is not NULL, the size of the returned data will be written into *szp.
*/
/* Some defines: Number of tries. */
#define SD_NTRIES 10
/* Percent of over-allocation (initial) */
#define SD_MARGIN 10
/*
* Factor for over-allocation in percent (the margin is increased by this on
* any failed try).
*/
#define SD_FACTOR 50
/* Maximum supported MIB depth */
#define SD_MAXMIB 16
char *
sysctl_dynread(const char *n, size_t *szp)
{
char *rv = NULL;
int mib[SD_MAXMIB];
size_t mibsz = SD_MAXMIB;
size_t mrg = SD_MARGIN;
size_t sz;
int i;
/* cache the MIB */
if (sysctlnametomib(n, mib, &mibsz) == -1) {
if (errno == ENOMEM) {
error("XXX: SD_MAXMIB too small, please bump!");
}
return NULL;
}
for (i = 0; i < SD_NTRIES; i++) {
/* get needed buffer size */
if (sysctl(mib, mibsz, NULL, &sz, NULL, 0) == -1)
break;
sz += sz * mrg / 100;
if ((rv = (char *)malloc(sz)) == NULL) {
error("Out of memory!");
return NULL;
}
if (sysctl(mib, mibsz, rv, &sz, NULL, 0) == -1) {
free(rv);
rv = NULL;
if (errno == ENOMEM) {
mrg += mrg * SD_FACTOR / 100;
} else
break;
} else {
/* success */
if (szp != NULL)
*szp = sz;
break;
}
}
return rv;
}
