1 /* 2 * Copyright (c) 1997, by Sun Microsystems, Inc. 3 * All rights reserved. 4 */ 5 6 #if defined(LIBC_SCCS) && !defined(lint) 7 static char sccsid[] = "@(#)setenv.c 8.1 (Berkeley) 6/4/93"; 8 static char rcsid[] = "$Id: setenv.c,v 8.4 1997/04/24 22:00:38 vixie Exp $"; 9 #endif /* LIBC_SCCS and not lint */ 10 11 /* 12 * Copyright (c) 1987, 1993 13 * The Regents of the University of California. All rights reserved. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 3. All advertising materials mentioning features or use of this software 24 * must display the following acknowledgement: 25 * This product includes software developed by the University of 26 * California, Berkeley and its contributors. 27 * 4. Neither the name of the University nor the names of its contributors 28 * may be used to endorse or promote products derived from this software 29 * without specific prior written permission. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 32 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 33 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 34 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 35 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 39 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 40 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 41 * SUCH DAMAGE. 42 */ 43 44 45 #pragma ident "%Z%%M% %I% %E% SMI" 46 47 #include "port_before.h" 48 49 #include <stddef.h> 50 #include <stdlib.h> 51 #include <string.h> 52 53 #include "port_after.h" 54 55 #if !defined(NEED_SETENV) 56 int __bindcompat_setenv; 57 #else 58 59 extern char **environ; 60 61 static char *findenv(const char *name, int *offset); 62 63 /* 64 * setenv -- 65 * Set the value of the environmental variable "name" to be 66 * "value". If rewrite is set, replace any current value. 67 */ 68 setenv(const char *name, const char *value, int rewrite) { 69 extern char **environ; 70 static int alloced; /* if allocated space before */ 71 char *c; 72 int l_value, offset; 73 74 if (*value == '=') /* no `=' in value */ 75 ++value; 76 l_value = strlen(value); 77 if ((c = findenv(name, &offset))) { /* find if already exists */ 78 if (!rewrite) 79 return (0); 80 if (strlen(c) >= l_value) { /* old larger; copy over */ 81 while (*c++ = *value++); 82 return (0); 83 } 84 } else { /* create new slot */ 85 int cnt; 86 char **p; 87 88 for (p = environ, cnt = 0; *p; ++p, ++cnt); 89 if (alloced) { /* just increase size */ 90 environ = (char **)realloc((char *)environ, 91 (size_t)(sizeof(char *) * (cnt + 2))); 92 if (!environ) 93 return (-1); 94 } 95 else { /* get new space */ 96 alloced = 1; /* copy old entries into it */ 97 p = malloc((size_t)(sizeof(char *) * (cnt + 2))); 98 if (!p) 99 return (-1); 100 memcpy(p, environ, cnt * sizeof(char *)); 101 environ = p; 102 } 103 environ[cnt + 1] = NULL; 104 offset = cnt; 105 } 106 for (c = (char *)name; *c && *c != '='; ++c); /* no `=' in name */ 107 if (!(environ[offset] = /* name + `=' + value */ 108 malloc((size_t)((int)(c - name) + l_value + 2)))) 109 return (-1); 110 for (c = environ[offset]; (*c = *name++) && *c != '='; ++c); 111 for (*c++ = '='; *c++ = *value++;); 112 return (0); 113 } 114 115 /* 116 * unsetenv(name) -- 117 * Delete environmental variable "name". 118 */ 119 void 120 unsetenv(const char *name) { 121 char **p; 122 int offset; 123 124 while (findenv(name, &offset)) /* if set multiple times */ 125 for (p = &environ[offset];; ++p) 126 if (!(*p = *(p + 1))) 127 break; 128 } 129 130 /* 131 * findenv -- 132 * Returns pointer to value associated with name, if any, else NULL. 133 * Sets offset to be the offset of the name/value combination in the 134 * environmental array, for use by setenv(3) and unsetenv(3). 135 * Explicitly removes '=' in argument name. 136 * 137 * This routine *should* be a static; don't use it. 138 */ 139 static char * 140 findenv(const char *name, int *offset) { 141 const char *np; 142 char **p, *c; 143 int len; 144 145 if (name == NULL || environ == NULL) 146 return (NULL); 147 for (np = name; *np && *np != '='; ++np) 148 continue; 149 len = np - name; 150 for (p = environ; (c = *p) != NULL; ++p) 151 if (strncmp(c, name, len) == 0 && c[len] == '=') { 152 *offset = p - environ; 153 return (c + len + 1); 154 } 155 return (NULL); 156 } 157 #endif 158