1 /* $NetBSD: setenv.c,v 1.8 1995/12/28 08:52:49 thorpej Exp $ */ 2 3 /* 4 * Copyright (c) 1987 Regents of the University of California. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char *sccsid = "from: @(#)setenv.c 5.6 (Berkeley) 6/4/91"; 39 #else 40 static char *rcsid = "$NetBSD: setenv.c,v 1.8 1995/12/28 08:52:49 thorpej Exp $"; 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <stdlib.h> 45 #include <string.h> 46 47 /* 48 * setenv -- 49 * Set the value of the environmental variable "name" to be 50 * "value". If rewrite is set, replace any current value. 51 */ 52 int 53 setenv(name, value, rewrite) 54 register const char *name; 55 register const char *value; 56 int rewrite; 57 { 58 extern char **environ; 59 static int alloced; /* if allocated space before */ 60 register char *C; 61 int l_value, offset; 62 char *__findenv(); 63 64 if (*value == '=') /* no `=' in value */ 65 ++value; 66 l_value = strlen(value); 67 if ((C = __findenv(name, &offset))) { /* find if already exists */ 68 if (!rewrite) 69 return (0); 70 if (strlen(C) >= l_value) { /* old larger; copy over */ 71 while (*C++ = *value++); 72 return (0); 73 } 74 } else { /* create new slot */ 75 register int cnt; 76 register char **P; 77 78 for (P = environ, cnt = 0; *P; ++P, ++cnt); 79 if (alloced) { /* just increase size */ 80 environ = (char **)realloc((char *)environ, 81 (size_t)(sizeof(char *) * (cnt + 2))); 82 if (!environ) 83 return (-1); 84 } 85 else { /* get new space */ 86 alloced = 1; /* copy old entries into it */ 87 P = (char **)malloc((size_t)(sizeof(char *) * 88 (cnt + 2))); 89 if (!P) 90 return (-1); 91 bcopy(environ, P, cnt * sizeof(char *)); 92 environ = P; 93 } 94 environ[cnt + 1] = NULL; 95 offset = cnt; 96 } 97 for (C = (char *)name; *C && *C != '='; ++C); /* no `=' in name */ 98 if (!(environ[offset] = /* name + `=' + value */ 99 malloc((size_t)((int)(C - name) + l_value + 2)))) 100 return (-1); 101 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 102 ; 103 for (*C++ = '='; *C++ = *value++; ) 104 ; 105 return (0); 106 } 107 108 /* 109 * unsetenv(name) -- 110 * Delete environmental variable "name". 111 */ 112 void 113 unsetenv(name) 114 const char *name; 115 { 116 extern char **environ; 117 register char **P; 118 int offset; 119 char *__findenv(); 120 121 while (__findenv(name, &offset)) /* if set multiple times */ 122 for (P = &environ[offset];; ++P) 123 if (!(*P = *(P + 1))) 124 break; 125 } 126