freebsd-dev/usr.bin/systat/fetch.c
Thomas Moestl 342e2faa09 Get rid of setgid kmem for systat, and while being there, fix some bugs
and compiler warnings.
The data for network statistics are still obtained via the kvm interface
if systat was started with the needed privileges, otherwise sysctls are
used. The reason for this is that with really many open sockets, the
sysctl method is probably slower, but it systat -netstat is probably not
really usable in either mode under these conditions.

Approved by:	rwatson
2001-03-23 03:58:25 +00:00

149 lines
4.1 KiB
C

/*-
* 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. 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.
*
* $FreeBSD$
*/
#ifndef lint
static char sccsid[] = "@(#)fetch.c 8.1 (Berkeley) 6/6/93";
#endif /* not lint */
#include <sys/types.h>
#include <sys/sysctl.h>
#include <errno.h>
#include <err.h>
#include <string.h>
#include <stdlib.h>
#include "systat.h"
#include "extern.h"
int
kvm_ckread(a, b, l)
void *a, *b;
int l;
{
if (kvm_read(kd, (u_long)a, b, l) != l) {
if (verbose)
error("error reading kmem at %x", a);
return (0);
}
else
return (1);
}
void getsysctl(name, ptr, len)
char *name;
void *ptr;
size_t len;
{
int err;
size_t nlen = len;
if ((err = sysctlbyname(name, ptr, &nlen, NULL, 0)) != 0) {
error("sysctl(%s...) failed: %s", name,
strerror(errno));
}
if (nlen != len) {
error("sysctl(%s...) expected %d, got %d", 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(n, szp)
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;
}