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
getsysctl(const char * name,void * ptr,size_t len)63 void getsysctl(const char *name, void *ptr, size_t len)
64 {
65 size_t nlen = len;
66 if (sysctlbyname(name, ptr, &nlen, NULL, 0) != 0) {
67 error("sysctl(%s...) failed: %s", name,
68 strerror(errno));
69 }
70 if (nlen != len) {
71 error("sysctl(%s...) expected %zu, got %zu", name, len, nlen);
72 }
73 }
74
75 /*
76 * Read sysctl data with variable size. Try some times (with increasing
77 * buffers), fail if still too small.
78 * This is needed sysctls with possibly raplidly increasing data sizes,
79 * but imposes little overhead in the case of constant sizes.
80 * Returns NULL on error, or a pointer to freshly malloc()'ed memory that holds
81 * the requested data.
82 * If szp is not NULL, the size of the returned data will be written into *szp.
83 */
84
85 /* Some defines: Number of tries. */
86 #define SD_NTRIES 10
87 /* Percent of over-allocation (initial) */
88 #define SD_MARGIN 10
89 /*
90 * Factor for over-allocation in percent (the margin is increased by this on
91 * any failed try).
92 */
93 #define SD_FACTOR 50
94 /* Maximum supported MIB depth */
95 #define SD_MAXMIB 16
96
97 char *
sysctl_dynread(const char * n,size_t * szp)98 sysctl_dynread(const char *n, size_t *szp)
99 {
100 char *rv = NULL;
101 int mib[SD_MAXMIB];
102 size_t mibsz = SD_MAXMIB;
103 size_t mrg = SD_MARGIN;
104 size_t sz;
105 int i;
106
107 /* cache the MIB */
108 if (sysctlnametomib(n, mib, &mibsz) == -1) {
109 if (errno == ENOMEM) {
110 error("XXX: SD_MAXMIB too small, please bump!");
111 }
112 return NULL;
113 }
114 for (i = 0; i < SD_NTRIES; i++) {
115 /* get needed buffer size */
116 if (sysctl(mib, mibsz, NULL, &sz, NULL, 0) == -1)
117 break;
118 sz += sz * mrg / 100;
119 if ((rv = (char *)malloc(sz)) == NULL) {
120 error("Out of memory!");
121 return NULL;
122 }
123 if (sysctl(mib, mibsz, rv, &sz, NULL, 0) == -1) {
124 free(rv);
125 rv = NULL;
126 if (errno == ENOMEM) {
127 mrg += mrg * SD_FACTOR / 100;
128 } else
129 break;
130 } else {
131 /* success */
132 if (szp != NULL)
133 *szp = sz;
134 break;
135 }
136 }
137
138 return rv;
139 }
140