1 /* 2 * Copyright (c) 1987 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifdef HAVE_CONFIG_H 35 # include "config.h" 36 #endif 37 #ifndef HAVE_SETENV 38 39 #if defined(LIBC_SCCS) && !defined(lint) 40 /*static char *sccsid = "from: @(#)setenv.c 5.6 (Berkeley) 6/4/91";*/ 41 static char *rcsid = "$Id: setenv.c,v 1.5 1996/09/04 22:10:42 sjg Exp $"; 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <stddef.h> 45 #include <stdlib.h> 46 #include <string.h> 47 48 /* 49 * __findenv -- 50 * Returns pointer to value associated with name, if any, else NULL. 51 * Sets offset to be the offset of the name/value combination in the 52 * environmental array, for use by setenv(3) and unsetenv(3). 53 * Explicitly removes '=' in argument name. 54 * 55 * This routine *should* be a static; don't use it. 56 */ 57 static char * 58 __findenv(name, offset) 59 register char *name; 60 int *offset; 61 { 62 extern char **environ; 63 register int len; 64 register char **P, *C; 65 66 for (C = name, len = 0; *C && *C != '='; ++C, ++len); 67 for (P = environ; *P; ++P) 68 if (!strncmp(*P, name, len)) 69 if (*(C = *P + len) == '=') { 70 *offset = P - environ; 71 return(++C); 72 } 73 return(NULL); 74 } 75 76 /* 77 * setenv -- 78 * Set the value of the environmental variable "name" to be 79 * "value". If rewrite is set, replace any current value. 80 */ 81 setenv(name, value, rewrite) 82 register const char *name; 83 register const char *value; 84 int rewrite; 85 { 86 extern char **environ; 87 static int alloced; /* if allocated space before */ 88 register char *C; 89 int l_value, offset; 90 char *__findenv(); 91 92 if (*value == '=') /* no `=' in value */ 93 ++value; 94 l_value = strlen(value); 95 if ((C = __findenv(name, &offset))) { /* find if already exists */ 96 if (!rewrite) 97 return (0); 98 if (strlen(C) >= l_value) { /* old larger; copy over */ 99 while (*C++ = *value++); 100 return (0); 101 } 102 } else { /* create new slot */ 103 register int cnt; 104 register char **P; 105 106 for (P = environ, cnt = 0; *P; ++P, ++cnt); 107 if (alloced) { /* just increase size */ 108 environ = (char **)realloc((char *)environ, 109 (size_t)(sizeof(char *) * (cnt + 2))); 110 if (!environ) 111 return (-1); 112 } 113 else { /* get new space */ 114 alloced = 1; /* copy old entries into it */ 115 P = (char **)malloc((size_t)(sizeof(char *) * 116 (cnt + 2))); 117 if (!P) 118 return (-1); 119 bcopy(environ, P, cnt * sizeof(char *)); 120 environ = P; 121 } 122 environ[cnt + 1] = NULL; 123 offset = cnt; 124 } 125 for (C = (char *)name; *C && *C != '='; ++C); /* no `=' in name */ 126 if (!(environ[offset] = /* name + `=' + value */ 127 malloc((size_t)((int)(C - name) + l_value + 2)))) 128 return (-1); 129 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 130 ; 131 for (*C++ = '='; *C++ = *value++; ) 132 ; 133 return (0); 134 } 135 136 /* 137 * unsetenv(name) -- 138 * Delete environmental variable "name". 139 */ 140 void 141 unsetenv(name) 142 const char *name; 143 { 144 extern char **environ; 145 register char **P; 146 int offset; 147 char *__findenv(); 148 149 while (__findenv(name, &offset)) /* if set multiple times */ 150 for (P = &environ[offset];; ++P) 151 if (!(*P = *(P + 1))) 152 break; 153 } 154 #endif 155