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 #include <sys/cdefs.h>
33
34 __FBSDID("$FreeBSD$");
35
36 #ifdef lint
37 static const char sccsid[] = "@(#)fetch.c 8.1 (Berkeley) 6/6/93";
38 #endif
39
40 #include <sys/types.h>
41 #include <sys/sysctl.h>
42
43 #include <err.h>
44 #include <errno.h>
45 #include <stdlib.h>
46 #include <string.h>
47
48 #include "systat.h"
49 #include "extern.h"
50
51 int
kvm_ckread(void * a,void * b,int l)52 kvm_ckread(void *a, void *b, int l)
53 {
54 if (kvm_read(kd, (u_long)a, b, l) != l) {
55 if (verbose)
56 error("error reading kmem at %p", a);
57 return (0);
58 }
59 else
60 return (1);
61 }
62
63 void
getsysctl(const char * name,void * ptr,size_t len)64 getsysctl(const char *name, void *ptr, size_t len)
65 {
66 size_t nlen = len;
67
68 if (sysctlbyname(name, ptr, &nlen, NULL, 0) != 0) {
69 error("sysctl(%s...) failed: %s", name,
70 strerror(errno));
71 }
72 if (nlen != len) {
73 error("sysctl(%s...) expected %zu, got %zu", name, len, nlen);
74 }
75 }
76
77 /*
78 * Read sysctl data with variable size. Try some times (with increasing
79 * buffers), fail if still too small.
80 * This is needed sysctls with possibly raplidly increasing data sizes,
81 * but imposes little overhead in the case of constant sizes.
82 * Returns NULL on error, or a pointer to freshly malloc()'ed memory that holds
83 * the requested data.
84 * If szp is not NULL, the size of the returned data will be written into *szp.
85 */
86
87 /* Some defines: Number of tries. */
88 #define SD_NTRIES 10
89 /* Percent of over-allocation (initial) */
90 #define SD_MARGIN 10
91 /*
92 * Factor for over-allocation in percent (the margin is increased by this on
93 * any failed try).
94 */
95 #define SD_FACTOR 50
96 /* Maximum supported MIB depth */
97 #define SD_MAXMIB 16
98
99 char *
sysctl_dynread(const char * n,size_t * szp)100 sysctl_dynread(const char *n, size_t *szp)
101 {
102 char *rv = NULL;
103 int mib[SD_MAXMIB];
104 size_t mibsz = SD_MAXMIB;
105 size_t mrg = SD_MARGIN;
106 size_t sz;
107 int i;
108
109 /* cache the MIB */
110 if (sysctlnametomib(n, mib, &mibsz) == -1) {
111 if (errno == ENOMEM) {
112 error("XXX: SD_MAXMIB too small, please bump!");
113 }
114 return NULL;
115 }
116 for (i = 0; i < SD_NTRIES; i++) {
117 /* get needed buffer size */
118 if (sysctl(mib, mibsz, NULL, &sz, NULL, 0) == -1)
119 break;
120 sz += sz * mrg / 100;
121 if ((rv = (char *)malloc(sz)) == NULL) {
122 error("Out of memory!");
123 return NULL;
124 }
125 if (sysctl(mib, mibsz, rv, &sz, NULL, 0) == -1) {
126 free(rv);
127 rv = NULL;
128 if (errno == ENOMEM) {
129 mrg += mrg * SD_FACTOR / 100;
130 } else
131 break;
132 } else {
133 /* success */
134 if (szp != NULL)
135 *szp = sz;
136 break;
137 }
138 }
139
140 return rv;
141 }
142