1 #if defined(LIBC_SCCS) && !defined(lint) 2 static const char sccsid[] = "@(#)setenv.c 8.1 (Berkeley) 6/4/93"; 3 static const char rcsid[] = "$Id: setenv.c,v 1.2 2005/04/27 04:56:11 sra Exp $"; 4 #endif /* LIBC_SCCS and not lint */ 5 6 /* 7 * Copyright (c) 1987, 1993 8 * The Regents of the University of California. All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include "port_before.h" 40 41 #include <stddef.h> 42 #include <stdlib.h> 43 #include <string.h> 44 45 #include "port_after.h" 46 47 #if !defined(NEED_SETENV) 48 int __bindcompat_setenv; 49 #else 50 51 extern char **environ; 52 53 static char *findenv(const char *name, int *offset); 54 55 /*% 56 * setenv -- 57 * Set the value of the environmental variable "name" to be 58 * "value". If rewrite is set, replace any current value. 59 */ 60 setenv(const char *name, const char *value, int rewrite) { 61 extern char **environ; 62 static int alloced; /*%< if allocated space before */ 63 char *c; 64 int l_value, offset; 65 66 if (*value == '=') /*%< no `=' in value */ 67 ++value; 68 l_value = strlen(value); 69 if ((c = findenv(name, &offset))) { /*%< find if already exists */ 70 if (!rewrite) 71 return (0); 72 if (strlen(c) >= l_value) { /*%< old larger; copy over */ 73 while (*c++ = *value++); 74 return (0); 75 } 76 } else { /*%< create new slot */ 77 int cnt; 78 char **p; 79 80 for (p = environ, cnt = 0; *p; ++p, ++cnt); 81 if (alloced) { /*%< just increase size */ 82 environ = (char **)realloc((char *)environ, 83 (size_t)(sizeof(char *) * (cnt + 2))); 84 if (!environ) 85 return (-1); 86 } 87 else { /*%< get new space */ 88 alloced = 1; /*%< copy old entries into it */ 89 p = malloc((size_t)(sizeof(char *) * (cnt + 2))); 90 if (!p) 91 return (-1); 92 memcpy(p, environ, cnt * sizeof(char *)); 93 environ = p; 94 } 95 environ[cnt + 1] = NULL; 96 offset = cnt; 97 } 98 for (c = (char *)name; *c && *c != '='; ++c); /*%< no `=' in name */ 99 if (!(environ[offset] = /*%< name + `=' + value */ 100 malloc((size_t)((int)(c - name) + l_value + 2)))) 101 return (-1); 102 for (c = environ[offset]; (*c = *name++) && *c != '='; ++c); 103 for (*c++ = '='; *c++ = *value++;); 104 return (0); 105 } 106 107 /*% 108 * unsetenv(name) -- 109 * Delete environmental variable "name". 110 */ 111 void 112 unsetenv(const char *name) { 113 char **p; 114 int offset; 115 116 while (findenv(name, &offset)) /*%< if set multiple times */ 117 for (p = &environ[offset];; ++p) 118 if (!(*p = *(p + 1))) 119 break; 120 } 121 122 /*% 123 * findenv -- 124 * Returns pointer to value associated with name, if any, else NULL. 125 * Sets offset to be the offset of the name/value combination in the 126 * environmental array, for use by setenv(3) and unsetenv(3). 127 * Explicitly removes '=' in argument name. 128 * 129 * This routine *should* be a static; don't use it. 130 */ 131 static char * 132 findenv(const char *name, int *offset) { 133 const char *np; 134 char **p, *c; 135 int len; 136 137 if (name == NULL || environ == NULL) 138 return (NULL); 139 for (np = name; *np && *np != '='; ++np) 140 continue; 141 len = np - name; 142 for (p = environ; (c = *p) != NULL; ++p) 143 if (strncmp(c, name, len) == 0 && c[len] == '=') { 144 *offset = p - environ; 145 return (c + len + 1); 146 } 147 return (NULL); 148 } 149 #endif 150 151 /*! \file */ 152