1 /* $NetBSD: setenv.c,v 1.38 2010/09/30 12:41:33 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 1.38 2010/09/30 12:41:33 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 #include "reentrant.h" 48 #include "local.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 /* 59 * setenv -- 60 * Set the value of the environmental variable "name" to be 61 * "value". If rewrite is set, replace any current value. 62 */ 63 int 64 setenv(const char *name, const char *value, int rewrite) 65 { 66 static char **saveenv; /* copy of previously allocated space */ 67 char *c, **newenv; 68 const char *cc; 69 size_t l_value, size; 70 int offset; 71 72 _DIAGASSERT(name != NULL); 73 _DIAGASSERT(value != NULL); 74 75 if (rwlock_wrlock(&__environ_lock) != 0) 76 return -1; 77 78 /* find if already exists */ 79 c = __findenv(name, &offset); 80 81 if (__allocenv(offset) == -1) 82 goto bad; 83 84 if (*value == '=') /* no `=' in value */ 85 ++value; 86 l_value = strlen(value); 87 88 if (c != NULL) { 89 if (!rewrite) 90 goto good; 91 if (strlen(c) >= l_value) /* old is enough; copy over */ 92 goto copy; 93 } else { /* create new slot */ 94 size = (size_t)(sizeof(char *) * (offset + 2)); 95 if (saveenv == environ) { /* just increase size */ 96 if ((newenv = realloc(saveenv, size)) == NULL) 97 goto bad; 98 saveenv = newenv; 99 } else { /* get new space */ 100 free(saveenv); 101 if ((saveenv = malloc(size)) == NULL) 102 goto bad; 103 (void)memcpy(saveenv, environ, size - sizeof(char *)); 104 } 105 environ = saveenv; 106 environ[offset + 1] = NULL; 107 } 108 for (cc = name; *cc && *cc != '='; ++cc) /* no `=' in name */ 109 continue; 110 size = cc - name; 111 /* name + `=' + value */ 112 if ((c = malloc(size + l_value + 2)) == NULL) 113 goto bad; 114 115 if (environ[offset] == __environ_malloced[offset]) 116 free(__environ_malloced[offset]); 117 118 environ[offset] = c; 119 __environ_malloced[offset] = c; 120 (void)memcpy(c, name, size); 121 c += size; 122 *c++ = '='; 123 124 copy: 125 (void)memcpy(c, value, l_value + 1); 126 good: 127 rwlock_unlock(&__environ_lock); 128 return 0; 129 bad: 130 rwlock_unlock(&__environ_lock); 131 return -1; 132 } 133