freebsd-skq/usr.bin/systat/fetch.c
pfg 872b698bd4 General further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:49:47 +00:00

141 lines
3.9 KiB
C

/*-
* 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/cdefs.h>
__FBSDID("$FreeBSD$");
#ifdef lint
static const char sccsid[] = "@(#)fetch.c 8.1 (Berkeley) 6/6/93";
#endif
#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 %lu, got %lu", name,
(unsigned long)len, (unsigned long)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;
}