1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright 2020 Stefan Eßer <se@freebsd.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/param.h> 32 #include <sys/sysctl.h> 33 #include <sys/limits.h> 34 #include <stdlib.h> 35 #include <paths.h> 36 #include <libutil.h> 37 #include <unistd.h> 38 39 #ifndef _PATH_LOCALBASE 40 #define _PATH_LOCALBASE "/usr/local" 41 #endif 42 43 const char * 44 getlocalbase(void) 45 { 46 static const int localbase_oid[2] = {CTL_USER, USER_LOCALBASE}; 47 char *tmppath; 48 size_t tmplen; 49 static const char *localbase = NULL; 50 51 if (issetugid() == 0) { 52 tmppath = getenv("LOCALBASE"); 53 if (tmppath != NULL && tmppath[0] != '\0') 54 return (tmppath); 55 } 56 if (sysctl(localbase_oid, 2, NULL, &tmplen, NULL, 0) == 0 && 57 (tmppath = malloc(tmplen)) != NULL && 58 sysctl(localbase_oid, 2, tmppath, &tmplen, NULL, 0) == 0) { 59 /* 60 * Check for some other thread already having 61 * set localbase - this should use atomic ops. 62 * The amount of memory allocated above may leak, 63 * if a parallel update in another thread is not 64 * detected and the non-NULL pointer is overwritten. 65 */ 66 if (tmppath[0] != '\0' && 67 (volatile const char*)localbase == NULL) 68 localbase = tmppath; 69 else 70 free((void*)tmppath); 71 return (localbase); 72 } 73 return (_PATH_LOCALBASE); 74 } 75