1 /* $NetBSD: setenv.c,v 1.43 2010/11/14 18:11:43 tron 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 1.43 2010/11/14 18:11:43 tron 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 48 #include "env.h" 49 #include "reentrant.h" 50 #include "local.h" 51 52 #ifdef __weak_alias 53 __weak_alias(setenv,_setenv) 54 #endif 55 56 /* 57 * setenv -- 58 * Set the value of the environmental variable "name" to be 59 * "value". If rewrite is set, replace any current value. 60 */ 61 int 62 setenv(const char *name, const char *value, int rewrite) 63 { 64 size_t l_name, l_value, length; 65 ssize_t offset; 66 char *envvar; 67 68 _DIAGASSERT(name != NULL); 69 _DIAGASSERT(value != NULL); 70 71 l_name = __envvarnamelen(name, false); 72 if (l_name == 0 || value == NULL) { 73 errno = EINVAL; 74 return -1; 75 } 76 77 if (!__writelockenv()) 78 return -1; 79 80 /* Find slot in the enviroment. */ 81 offset = __getenvslot(name, l_name, true); 82 if (offset == -1) 83 goto bad; 84 85 l_value = strlen(value); 86 length = l_name + l_value + 2; 87 88 /* Handle overwriting a current environt variable. */ 89 envvar = environ[offset]; 90 if (envvar != NULL) { 91 if (!rewrite) 92 goto good; 93 /* 94 * Check whether the buffer was allocated via setenv(3) and 95 * whether there is enough space. If so simply overwrite the 96 * existing value. 97 */ 98 if (__canoverwriteenvvar(envvar, length)) { 99 envvar += l_name + 1; 100 goto copy; 101 } 102 } 103 104 /* Allocate memory for name + `=' + value + NUL. */ 105 if ((envvar = __allocenvvar(length)) == NULL) 106 goto bad; 107 108 if (environ[offset] != NULL) 109 __freeenvvar(environ[offset]); 110 111 environ[offset] = envvar; 112 113 (void)memcpy(envvar, name, l_name); 114 115 envvar += l_name; 116 *envvar++ = '='; 117 118 copy: 119 (void)memcpy(envvar, value, l_value + 1); 120 121 good: 122 (void)__unlockenv(); 123 return 0; 124 125 bad: 126 (void)__unlockenv(); 127 return -1; 128 } 129