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 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 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 * 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