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 1.5 1993/10/15 01:26:44 jtc Exp $"; 37 #endif /* LIBC_SCCS and not lint */ 38 39 #include <stddef.h> 40 #include <stdlib.h> 41 #include <string.h> 42 43 /* 44 * setenv -- 45 * Set the value of the environmental variable "name" to be 46 * "value". If rewrite is set, replace any current value. 47 */ 48 setenv(name, value, rewrite) 49 register const char *name; 50 register const char *value; 51 int rewrite; 52 { 53 extern char **environ; 54 static int alloced; /* if allocated space before */ 55 register char *C; 56 int l_value, offset; 57 char *__findenv(); 58 59 if (*value == '=') /* no `=' in value */ 60 ++value; 61 l_value = strlen(value); 62 if ((C = __findenv(name, &offset))) { /* find if already exists */ 63 if (!rewrite) 64 return (0); 65 if (strlen(C) >= l_value) { /* old larger; copy over */ 66 while (*C++ = *value++); 67 return (0); 68 } 69 } else { /* create new slot */ 70 register int cnt; 71 register char **P; 72 73 for (P = environ, cnt = 0; *P; ++P, ++cnt); 74 if (alloced) { /* just increase size */ 75 environ = (char **)realloc((char *)environ, 76 (size_t)(sizeof(char *) * (cnt + 2))); 77 if (!environ) 78 return (-1); 79 } 80 else { /* get new space */ 81 alloced = 1; /* copy old entries into it */ 82 P = (char **)malloc((size_t)(sizeof(char *) * 83 (cnt + 2))); 84 if (!P) 85 return (-1); 86 bcopy(environ, P, cnt * sizeof(char *)); 87 environ = P; 88 } 89 environ[cnt + 1] = NULL; 90 offset = cnt; 91 } 92 for (C = (char *)name; *C && *C != '='; ++C); /* no `=' in name */ 93 if (!(environ[offset] = /* name + `=' + value */ 94 malloc((size_t)((int)(C - name) + l_value + 2)))) 95 return (-1); 96 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 97 ; 98 for (*C++ = '='; *C++ = *value++; ) 99 ; 100 return (0); 101 } 102 103 /* 104 * unsetenv(name) -- 105 * Delete environmental variable "name". 106 */ 107 void 108 unsetenv(name) 109 const char *name; 110 { 111 extern char **environ; 112 register char **P; 113 int offset; 114 char *__findenv(); 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