1 /* $NetBSD: setenv.c,v 1.41 2010/10/16 11:23:41 njoly Exp $ */ 2 3 /* 4 * Copyright (c) 1987, 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[] = "@(#)setenv.c 8.1 (Berkeley) 6/4/93"; 36 #else 37 __RCSID("$NetBSD: setenv.c,v 1.41 2010/10/16 11:23:41 njoly Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 43 #include <assert.h> 44 #include <errno.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include "reentrant.h" 48 #include "local.h" 49 50 #ifdef __weak_alias 51 __weak_alias(setenv,_setenv) 52 #endif 53 54 /* 55 * setenv -- 56 * Set the value of the environmental variable "name" to be 57 * "value". If rewrite is set, replace any current value. 58 */ 59 int 60 setenv(const char *name, const char *value, int rewrite) 61 { 62 char *c; 63 size_t l_value, size; 64 int offset; 65 66 _DIAGASSERT(name != NULL); 67 _DIAGASSERT(value != NULL); 68 69 if (name == NULL || value == NULL) { 70 errno = EINVAL; 71 return -1; 72 } 73 74 size = strcspn(name, "="); 75 if (size == 0 || name[size] != '\0') { 76 errno = EINVAL; 77 return -1; 78 } 79 80 if (rwlock_wrlock(&__environ_lock) != 0) 81 return -1; 82 83 /* find if already exists */ 84 c = __findenv(name, &offset); 85 86 if (__allocenv(offset) == -1) 87 goto bad; 88 89 l_value = strlen(value); 90 91 if (c != NULL) { 92 if (!rewrite) 93 goto good; 94 /* 95 * Check whether the buffer was allocated via setenv(3) and 96 * whether there is enough space. If so simply overwrite the 97 * existing value. 98 */ 99 if (environ[offset] == __environ_malloced[offset] && 100 strlen(c) >= l_value) { 101 goto copy; 102 } 103 } 104 /* name + `=' + value */ 105 if ((c = malloc(size + l_value + 2)) == NULL) 106 goto bad; 107 108 if (environ[offset] == __environ_malloced[offset]) 109 free(__environ_malloced[offset]); 110 111 environ[offset] = c; 112 __environ_malloced[offset] = c; 113 (void)memcpy(c, name, size); 114 c += size; 115 *c++ = '='; 116 117 copy: 118 (void)memcpy(c, value, l_value + 1); 119 good: 120 rwlock_unlock(&__environ_lock); 121 return 0; 122 bad: 123 rwlock_unlock(&__environ_lock); 124 return -1; 125 } 126