1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 1987 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1984 AT&T */ 28 /* All Rights Reserved */ 29 30 #pragma ident "%Z%%M% %I% %E% SMI" 31 32 /* LINTLIBRARY */ 33 /* putenv - change environment variables 34 * 35 * input - char *change = a pointer to a string of the form 36 * "name=value" 37 * 38 * output - 0, if successful 39 * 1, otherwise 40 */ 41 42 #include <stdio.h> 43 #include <stdlib.h> 44 45 extern char **environ; /* pointer to enviroment */ 46 static int reall; /* flag to reallocate space, if putenv is called 47 more than once */ 48 static int find(char *); 49 static int match(char *, char *); 50 51 int 52 putenv(char *change) 53 { 54 char **newenv; /* points to new environment */ 55 int which; /* index of variable to replace */ 56 57 if ((which = find(change)) < 0) { 58 /* if a new variable */ 59 /* which is negative of table size, so invert and 60 count new element */ 61 which = (-which) + 1; 62 if (reall) { 63 /* we have expanded environ before */ 64 newenv = (char **)realloc(environ, 65 which*sizeof(char *)); 66 if (newenv == NULL) return (-1); 67 /* now that we have space, change environ */ 68 environ = newenv; 69 } else { 70 /* environ points to the original space */ 71 reall++; 72 newenv = (char **)malloc(which*sizeof(char *)); 73 if (newenv == NULL) return (-1); 74 (void)memcpy((char *)newenv, (char *)environ, 75 (int)(which*sizeof(char *))); 76 environ = newenv; 77 } 78 environ[which-2] = change; 79 environ[which-1] = NULL; 80 } else { 81 /* we are replacing an old variable */ 82 environ[which] = change; 83 } 84 return (0); 85 } 86 87 /* find - find where s2 is in environ 88 * 89 * input - str = string of form name=value 90 * 91 * output - index of name in environ that matches "name" 92 * -size of table, if none exists 93 */ 94 static int 95 find(char *str) 96 { 97 int ct = 0; /* index into environ */ 98 99 while(environ[ct] != NULL) { 100 if (match(environ[ct], str) != 0) 101 return (ct); 102 ct++; 103 } 104 return (-(++ct)); 105 } 106 /* 107 * s1 is either name, or name=value 108 * s2 is name=value 109 * if names match, return value of 1, 110 * else return 0 111 */ 112 113 static int 114 match(char *s1, char *s2) 115 { 116 while(*s1 == *s2++) { 117 if (*s1 == '=') 118 return (1); 119 s1++; 120 } 121 return (0); 122 } 123