1 /* $NetBSD: setenv.c,v 1.29 2005/02/17 21:22:25 christos 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 1.29 2005/02/17 21:22:25 christos 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 "local.h" 48 #include "reentrant.h" 49 50 #ifdef __weak_alias 51 __weak_alias(setenv,_setenv) 52 #endif 53 54 #ifdef _REENTRANT 55 extern rwlock_t __environ_lock; 56 #endif 57 58 extern char **environ; 59 60 /* 61 * setenv -- 62 * Set the value of the environmental variable "name" to be 63 * "value". If rewrite is set, replace any current value. 64 */ 65 int 66 setenv(name, value, rewrite) 67 const char *name; 68 const char *value; 69 int rewrite; 70 { 71 static char **saveenv; /* copy of previously allocated space */ 72 char *c, **newenv; 73 const char *cc; 74 size_t l_value, size; 75 int offset; 76 77 _DIAGASSERT(name != NULL); 78 _DIAGASSERT(value != NULL); 79 80 if (*value == '=') /* no `=' in value */ 81 ++value; 82 l_value = strlen(value); 83 rwlock_wrlock(&__environ_lock); 84 /* find if already exists */ 85 if ((c = __findenv(name, &offset)) != NULL) { 86 if (!rewrite) 87 goto good; 88 if (strlen(c) >= l_value) /* old larger; copy over */ 89 goto copy; 90 } else { /* create new slot */ 91 size_t cnt; 92 93 for (cnt = 0; environ[cnt]; ++cnt) 94 continue; 95 size = (size_t)(sizeof(char *) * (cnt + 2)); 96 if (saveenv == environ) { /* just increase size */ 97 if ((newenv = realloc(saveenv, size)) == NULL) 98 goto bad; 99 saveenv = newenv; 100 } else { /* get new space */ 101 free(saveenv); 102 if ((saveenv = malloc(size)) == NULL) 103 goto bad; 104 (void)memcpy(saveenv, environ, cnt * sizeof(char *)); 105 } 106 environ = saveenv; 107 environ[cnt + 1] = NULL; 108 offset = (int)cnt; 109 } 110 for (cc = name; *cc && *cc != '='; ++cc) /* no `=' in name */ 111 continue; 112 size = cc - name; 113 /* name + `=' + value */ 114 if ((environ[offset] = malloc(size + l_value + 2)) == NULL) 115 goto bad; 116 c = environ[offset]; 117 (void)memcpy(c, name, size); 118 c += size; 119 *c++ = '='; 120 copy: 121 (void)memcpy(c, value, l_value + 1); 122 good: 123 rwlock_unlock(&__environ_lock); 124 return 0; 125 bad: 126 rwlock_unlock(&__environ_lock); 127 return -1; 128 } 129