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
45 int
kvm_ckread(void * a,void * b,int l)46 kvm_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
57 void
getsysctl(const char * name,void * ptr,size_t len)58 getsysctl(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
93 char *
sysctl_dynread(const char * n,size_t * szp)94 sysctl_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