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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <sys/cdefs.h> 35 36 __FBSDID("$FreeBSD$"); 37 38 #ifdef lint 39 static const char sccsid[] = "@(#)fetch.c 8.1 (Berkeley) 6/6/93"; 40 #endif 41 42 #include <sys/types.h> 43 #include <sys/sysctl.h> 44 45 #include <err.h> 46 #include <errno.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "systat.h" 51 #include "extern.h" 52 53 int 54 kvm_ckread(void *a, void *b, int l) 55 { 56 if (kvm_read(kd, (u_long)a, b, l) != l) { 57 if (verbose) 58 error("error reading kmem at %p", a); 59 return (0); 60 } 61 else 62 return (1); 63 } 64 65 void getsysctl(const char *name, void *ptr, size_t len) 66 { 67 size_t nlen = len; 68 if (sysctlbyname(name, ptr, &nlen, NULL, 0) != 0) { 69 error("sysctl(%s...) failed: %s", name, 70 strerror(errno)); 71 } 72 if (nlen != len) { 73 error("sysctl(%s...) expected %lu, got %lu", name, 74 (unsigned long)len, (unsigned long)nlen); 75 } 76 } 77 78 /* 79 * Read sysctl data with variable size. Try some times (with increasing 80 * buffers), fail if still too small. 81 * This is needed sysctls with possibly raplidly increasing data sizes, 82 * but imposes little overhead in the case of constant sizes. 83 * Returns NULL on error, or a pointer to freshly malloc()'ed memory that holds 84 * the requested data. 85 * If szp is not NULL, the size of the returned data will be written into *szp. 86 */ 87 88 /* Some defines: Number of tries. */ 89 #define SD_NTRIES 10 90 /* Percent of over-allocation (initial) */ 91 #define SD_MARGIN 10 92 /* 93 * Factor for over-allocation in percent (the margin is increased by this on 94 * any failed try). 95 */ 96 #define SD_FACTOR 50 97 /* Maximum supported MIB depth */ 98 #define SD_MAXMIB 16 99 100 char * 101 sysctl_dynread(const char *n, size_t *szp) 102 { 103 char *rv = NULL; 104 int mib[SD_MAXMIB]; 105 size_t mibsz = SD_MAXMIB; 106 size_t mrg = SD_MARGIN; 107 size_t sz; 108 int i; 109 110 /* cache the MIB */ 111 if (sysctlnametomib(n, mib, &mibsz) == -1) { 112 if (errno == ENOMEM) { 113 error("XXX: SD_MAXMIB too small, please bump!"); 114 } 115 return NULL; 116 } 117 for (i = 0; i < SD_NTRIES; i++) { 118 /* get needed buffer size */ 119 if (sysctl(mib, mibsz, NULL, &sz, NULL, 0) == -1) 120 break; 121 sz += sz * mrg / 100; 122 if ((rv = (char *)malloc(sz)) == NULL) { 123 error("Out of memory!"); 124 return NULL; 125 } 126 if (sysctl(mib, mibsz, rv, &sz, NULL, 0) == -1) { 127 free(rv); 128 rv = NULL; 129 if (errno == ENOMEM) { 130 mrg += mrg * SD_FACTOR / 100; 131 } else 132 break; 133 } else { 134 /* success */ 135 if (szp != NULL) 136 *szp = sz; 137 break; 138 } 139 } 140 141 return rv; 142 } 143