1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1980, 1992, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32
33
34#include <sys/types.h>
35#include <sys/sysctl.h>
36
37#include <err.h>
38#include <errno.h>
39#include <stdlib.h>
40#include <string.h>
41
42#include "systat.h"
43#include "extern.h"
44
45int
46kvm_ckread(void *a, void *b, int l)
47{
48	if (kvm_read(kd, (u_long)a, b, l) != l) {
49		if (verbose)
50			error("error reading kmem at %p", a);
51		return (0);
52	}
53	else
54		return (1);
55}
56
57void
58getsysctl(const char *name, void *ptr, size_t len)
59{
60	size_t nlen = len;
61
62	if (sysctlbyname(name, ptr, &nlen, NULL, 0) != 0) {
63		error("sysctl(%s...) failed: %s", name,
64		    strerror(errno));
65	}
66	if (nlen != len) {
67		error("sysctl(%s...) expected %zu, got %zu", name, len, nlen);
68	}
69}
70
71/*
72 * Read sysctl data with variable size. Try some times (with increasing
73 * buffers), fail if still too small.
74 * This is needed sysctls with possibly raplidly increasing data sizes,
75 * but imposes little overhead in the case of constant sizes.
76 * Returns NULL on error, or a pointer to freshly malloc()'ed memory that holds
77 * the requested data.
78 * If szp is not NULL, the size of the returned data will be written into *szp.
79 */
80
81/* Some defines: Number of tries. */
82#define SD_NTRIES  10
83/* Percent of over-allocation (initial) */
84#define SD_MARGIN  10
85/*
86 * Factor for over-allocation in percent (the margin is increased by this on
87 * any failed try).
88 */
89#define SD_FACTOR  50
90/* Maximum supported MIB depth */
91#define SD_MAXMIB  16
92
93char *
94sysctl_dynread(const char *n, size_t *szp)
95{
96	char   *rv = NULL;
97	int    mib[SD_MAXMIB];
98	size_t mibsz = SD_MAXMIB;
99	size_t mrg = SD_MARGIN;
100	size_t sz;
101	int i;
102
103	/* cache the MIB */
104	if (sysctlnametomib(n, mib, &mibsz) == -1) {
105		if (errno == ENOMEM) {
106			error("XXX: SD_MAXMIB too small, please bump!");
107		}
108		return NULL;
109	}
110	for (i = 0; i < SD_NTRIES; i++) {
111		/* get needed buffer size */
112		if (sysctl(mib, mibsz, NULL, &sz, NULL, 0) == -1)
113			break;
114		sz += sz * mrg / 100;
115		if ((rv = (char *)malloc(sz)) == NULL) {
116			error("Out of memory!");
117			return NULL;
118		}
119		if (sysctl(mib, mibsz, rv, &sz, NULL, 0) == -1) {
120			free(rv);
121			rv = NULL;
122			if (errno == ENOMEM) {
123				mrg += mrg * SD_FACTOR / 100;
124			} else
125				break;
126		} else {
127			/* success */
128			if (szp != NULL)
129				*szp = sz;
130			break;
131		}
132	}
133
134	return rv;
135}
136