1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause-FreeBSD 3 * 4 * Copyright (c) 2003 Poul-Henning Kamp 5 * 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. The names of the authors may not be used to endorse or promote 16 * products derived from this software without specific prior written 17 * permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 * $FreeBSD$ 32 */ 33 34 #include <sys/types.h> 35 #include <sys/sysctl.h> 36 #include <errno.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include "libgeom.h" 40 41 /* 42 * Amount of extra space we allocate to try and anticipate the size of 43 * confxml. 44 */ 45 #define GEOM_GETXML_SLACK 4096 46 47 /* 48 * Number of times to retry in the face of the size of confxml exceeding 49 * that of our buffer. 50 */ 51 #define GEOM_GETXML_RETRIES 4 52 53 char * 54 geom_getxml(void) 55 { 56 char *p; 57 size_t l = 0; 58 int mib[3]; 59 size_t sizep; 60 int retries; 61 62 sizep = sizeof(mib) / sizeof(*mib); 63 if (sysctlnametomib("kern.geom.confxml", mib, &sizep) != 0) 64 return (NULL); 65 if (sysctl(mib, sizep, NULL, &l, NULL, 0) != 0) 66 return (NULL); 67 l += GEOM_GETXML_SLACK; 68 69 for (retries = 0; retries < GEOM_GETXML_RETRIES; retries++) { 70 p = malloc(l); 71 if (p == NULL) 72 return (NULL); 73 if (sysctl(mib, sizep, p, &l, NULL, 0) == 0) 74 return (reallocf(p, strlen(p) + 1)); 75 76 free(p); 77 78 if (errno != ENOMEM) 79 return (NULL); 80 81 /* 82 * Our buffer wasn't big enough. Make it bigger and 83 * try again. 84 */ 85 l *= 2; 86 } 87 88 return (NULL); 89 } 90