1 /* $NetBSD: confstr.c,v 1.13 2012/06/25 22:32:43 abs Exp $ */ 2 3 /*- 4 * Copyright (c) 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 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)confstr.c 8.1 (Berkeley) 6/4/93"; 36 #else 37 __RCSID("$NetBSD: confstr.c,v 1.13 2012/06/25 22:32:43 abs Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 #include <sys/param.h> 43 #include <sys/sysctl.h> 44 45 #include <errno.h> 46 #include <paths.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <unistd.h> 50 51 #ifdef __weak_alias 52 __weak_alias(confstr,_confstr) 53 #endif 54 55 size_t 56 confstr(int name, char *buf, size_t len) 57 { 58 size_t tlen; 59 int mib[2], sverrno; 60 char *p; 61 62 /* 63 * POSIX 1003.2 requires errors to return 0 -- 64 * that is *really* useful. 65 */ 66 switch (name) { 67 case _CS_PATH: 68 mib[0] = CTL_USER; 69 mib[1] = USER_CS_PATH; 70 if (sysctl(mib, 2, NULL, &tlen, NULL, 0) == -1) 71 return 0; 72 if (len != 0 && buf != NULL) { 73 if ((p = malloc(tlen)) == NULL) 74 return 0; 75 if (sysctl(mib, 2, p, &tlen, NULL, 0) == -1) { 76 sverrno = errno; 77 free(p); 78 errno = sverrno; 79 return 0; 80 } 81 /* 82 * POSIX 1003.2 requires partial return of 83 * the string -- that is even more useful. 84 */ 85 (void)strncpy(buf, p, len - 1); 86 buf[len - 1] = '\0'; 87 free(p); 88 } 89 return tlen + 1; 90 default: 91 errno = EINVAL; 92 return 0; 93 } 94 /* NOTREACHED */ 95 } 96