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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #if defined(LIBC_SCCS) && !defined(lint) 31 static char *rcsid = "$OpenBSD: setenv.c,v 1.8 2005/03/30 18:51:49 pat Exp $"; 32 #endif /* LIBC_SCCS and not lint */ 33 34 #include <stdlib.h> 35 #include <string.h> 36 37 char *__findenv(const char *name, int *offset); 38 39 extern char **environ; 40 41 /* 42 * setenv -- 43 * Set the value of the environmental variable "name" to be 44 * "value". If rewrite is set, replace any current value. 45 */ 46 int 47 setenv(const char *name, const char *value, int rewrite) 48 { 49 static char **lastenv; /* last value of environ */ 50 char *C; 51 int l_value, offset; 52 53 if (*value == '=') /* no `=' in value */ 54 ++value; 55 l_value = strlen(value); 56 if ((C = __findenv(name, &offset))) { /* find if already exists */ 57 if (!rewrite) 58 return (0); 59 if (strlen(C) >= l_value) { /* old larger; copy over */ 60 while ((*C++ = *value++)) 61 ; 62 return (0); 63 } 64 } else { /* create new slot */ 65 size_t cnt; 66 char **P; 67 68 for (P = environ; *P != NULL; P++) 69 ; 70 cnt = P - environ; 71 P = (char **)realloc(lastenv, sizeof(char *) * (cnt + 2)); 72 if (!P) 73 return (-1); 74 if (lastenv != environ) 75 memcpy(P, environ, cnt * sizeof(char *)); 76 lastenv = environ = P; 77 offset = cnt; 78 environ[cnt + 1] = NULL; 79 } 80 for (C = (char *)name; *C && *C != '='; ++C) 81 ; /* no `=' in name */ 82 if (!(environ[offset] = /* name + `=' + value */ 83 malloc((size_t)((int)(C - name) + l_value + 2)))) 84 return (-1); 85 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 86 ; 87 for (*C++ = '='; (*C++ = *value++); ) 88 ; 89 return (0); 90 } 91 92 /* 93 * unsetenv(name) -- 94 * Delete environmental variable "name". 95 */ 96 void 97 unsetenv(const char *name) 98 { 99 char **P; 100 int offset; 101 102 while (__findenv(name, &offset)) /* if set multiple times */ 103 for (P = &environ[offset];; ++P) 104 if (!(*P = *(P + 1))) 105 break; 106 } 107