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 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 { 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 %lu, got %lu", name, 72 (unsigned long)len, (unsigned long)nlen); 73 } 74 } 75 76 /* 77 * Read sysctl data with variable size. Try some times (with increasing 78 * buffers), fail if still too small. 79 * This is needed sysctls with possibly raplidly increasing data sizes, 80 * but imposes little overhead in the case of constant sizes. 81 * Returns NULL on error, or a pointer to freshly malloc()'ed memory that holds 82 * the requested data. 83 * If szp is not NULL, the size of the returned data will be written into *szp. 84 */ 85 86 /* Some defines: Number of tries. */ 87 #define SD_NTRIES 10 88 /* Percent of over-allocation (initial) */ 89 #define SD_MARGIN 10 90 /* 91 * Factor for over-allocation in percent (the margin is increased by this on 92 * any failed try). 93 */ 94 #define SD_FACTOR 50 95 /* Maximum supported MIB depth */ 96 #define SD_MAXMIB 16 97 98 char * 99 sysctl_dynread(const char *n, size_t *szp) 100 { 101 char *rv = NULL; 102 int mib[SD_MAXMIB]; 103 size_t mibsz = SD_MAXMIB; 104 size_t mrg = SD_MARGIN; 105 size_t sz; 106 int i; 107 108 /* cache the MIB */ 109 if (sysctlnametomib(n, mib, &mibsz) == -1) { 110 if (errno == ENOMEM) { 111 error("XXX: SD_MAXMIB too small, please bump!"); 112 } 113 return NULL; 114 } 115 for (i = 0; i < SD_NTRIES; i++) { 116 /* get needed buffer size */ 117 if (sysctl(mib, mibsz, NULL, &sz, NULL, 0) == -1) 118 break; 119 sz += sz * mrg / 100; 120 if ((rv = (char *)malloc(sz)) == NULL) { 121 error("Out of memory!"); 122 return NULL; 123 } 124 if (sysctl(mib, mibsz, rv, &sz, NULL, 0) == -1) { 125 free(rv); 126 rv = NULL; 127 if (errno == ENOMEM) { 128 mrg += mrg * SD_FACTOR / 100; 129 } else 130 break; 131 } else { 132 /* success */ 133 if (szp != NULL) 134 *szp = sz; 135 break; 136 } 137 } 138 139 return rv; 140 } 141