1 /* $NetBSD: setenv.c,v 1.9 1997/07/13 20:16:56 christos 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 #include <sys/cdefs.h> 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char *sccsid = "from: @(#)setenv.c 5.6 (Berkeley) 6/4/91"; 40 #else 41 __RCSID("$NetBSD: setenv.c,v 1.9 1997/07/13 20:16:56 christos Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include <stdlib.h> 46 #include <string.h> 47 #include "local.h" 48 49 /* 50 * setenv -- 51 * Set the value of the environmental variable "name" to be 52 * "value". If rewrite is set, replace any current value. 53 */ 54 int 55 setenv(name, value, rewrite) 56 register const char *name; 57 register const char *value; 58 int rewrite; 59 { 60 extern char **environ; 61 static int alloced; /* if allocated space before */ 62 register char *C; 63 int l_value, offset; 64 65 if (*value == '=') /* no `=' in value */ 66 ++value; 67 l_value = strlen(value); 68 if ((C = __findenv(name, &offset))) { /* find if already exists */ 69 if (!rewrite) 70 return (0); 71 if (strlen(C) >= l_value) { /* old larger; copy over */ 72 while ((*C++ = *value++) != '\0'); 73 return (0); 74 } 75 } else { /* create new slot */ 76 register int cnt; 77 register char **P; 78 79 for (P = environ, cnt = 0; *P; ++P, ++cnt); 80 if (alloced) { /* just increase size */ 81 environ = (char **)realloc((char *)environ, 82 (size_t)(sizeof(char *) * (cnt + 2))); 83 if (!environ) 84 return (-1); 85 } 86 else { /* get new space */ 87 alloced = 1; /* copy old entries into it */ 88 P = (char **)malloc((size_t)(sizeof(char *) * 89 (cnt + 2))); 90 if (!P) 91 return (-1); 92 bcopy(environ, P, cnt * sizeof(char *)); 93 environ = P; 94 } 95 environ[cnt + 1] = NULL; 96 offset = cnt; 97 } 98 for (C = (char *)name; *C && *C != '='; ++C); /* no `=' in name */ 99 if (!(environ[offset] = /* name + `=' + value */ 100 malloc((size_t)((int)(C - name) + l_value + 2)))) 101 return (-1); 102 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 103 ; 104 for (*C++ = '='; (*C++ = *value++) != '\0'; ) 105 ; 106 return (0); 107 } 108 109 /* 110 * unsetenv(name) -- 111 * Delete environmental variable "name". 112 */ 113 void 114 unsetenv(name) 115 const char *name; 116 { 117 extern char **environ; 118 register char **P; 119 int offset; 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