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 #if defined(LIBC_SCCS) && !defined(lint) 35 /*static char *sccsid = "from: @(#)setenv.c 5.6 (Berkeley) 6/4/91";*/ 36 static char *rcsid = "$Id: setenv.c,v 1.6 1995/02/28 01:46:53 jtc Exp $"; 37 #endif /* LIBC_SCCS and not lint */ 38 39 #include <stdlib.h> 40 #include <string.h> 41 42 /* 43 * setenv -- 44 * Set the value of the environmental variable "name" to be 45 * "value". If rewrite is set, replace any current value. 46 */ 47 setenv(name, value, rewrite) 48 register const char *name; 49 register const char *value; 50 int rewrite; 51 { 52 extern char **environ; 53 static int alloced; /* if allocated space before */ 54 register char *C; 55 int l_value, offset; 56 char *__findenv(); 57 58 if (*value == '=') /* no `=' in value */ 59 ++value; 60 l_value = strlen(value); 61 if ((C = __findenv(name, &offset))) { /* find if already exists */ 62 if (!rewrite) 63 return (0); 64 if (strlen(C) >= l_value) { /* old larger; copy over */ 65 while (*C++ = *value++); 66 return (0); 67 } 68 } else { /* create new slot */ 69 register int cnt; 70 register char **P; 71 72 for (P = environ, cnt = 0; *P; ++P, ++cnt); 73 if (alloced) { /* just increase size */ 74 environ = (char **)realloc((char *)environ, 75 (size_t)(sizeof(char *) * (cnt + 2))); 76 if (!environ) 77 return (-1); 78 } 79 else { /* get new space */ 80 alloced = 1; /* copy old entries into it */ 81 P = (char **)malloc((size_t)(sizeof(char *) * 82 (cnt + 2))); 83 if (!P) 84 return (-1); 85 bcopy(environ, P, cnt * sizeof(char *)); 86 environ = P; 87 } 88 environ[cnt + 1] = NULL; 89 offset = cnt; 90 } 91 for (C = (char *)name; *C && *C != '='; ++C); /* no `=' in name */ 92 if (!(environ[offset] = /* name + `=' + value */ 93 malloc((size_t)((int)(C - name) + l_value + 2)))) 94 return (-1); 95 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 96 ; 97 for (*C++ = '='; *C++ = *value++; ) 98 ; 99 return (0); 100 } 101 102 /* 103 * unsetenv(name) -- 104 * Delete environmental variable "name". 105 */ 106 void 107 unsetenv(name) 108 const char *name; 109 { 110 extern char **environ; 111 register char **P; 112 int offset; 113 char *__findenv(); 114 115 while (__findenv(name, &offset)) /* if set multiple times */ 116 for (P = &environ[offset];; ++P) 117 if (!(*P = *(P + 1))) 118 break; 119 } 120