1 /*-
2 * Copyright (c) 1980, 1992, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <sys/cdefs.h>
31
32 __FBSDID("$FreeBSD$");
33
34 #ifdef lint
35 static const char sccsid[] = "@(#)fetch.c 8.1 (Berkeley) 6/6/93";
36 #endif
37
38 #include <sys/types.h>
39 #include <sys/sysctl.h>
40
41 #include <err.h>
42 #include <errno.h>
43 #include <stdlib.h>
44 #include <string.h>
45
46 #include "systat.h"
47 #include "extern.h"
48
49 int
kvm_ckread(void * a,void * b,int l)50 kvm_ckread(void *a, void *b, int l)
51 {
52 if (kvm_read(kd, (u_long)a, b, l) != l) {
53 if (verbose)
54 error("error reading kmem at %p", a);
55 return (0);
56 }
57 else
58 return (1);
59 }
60
getsysctl(const char * name,void * ptr,size_t len)61 void getsysctl(const char *name, void *ptr, size_t len)
62 {
63 size_t nlen = len;
64 if (sysctlbyname(name, ptr, &nlen, NULL, 0) != 0) {
65 error("sysctl(%s...) failed: %s", name,
66 strerror(errno));
67 }
68 if (nlen != len) {
69 error("sysctl(%s...) expected %lu, got %lu", name,
70 (unsigned long)len, (unsigned long)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