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