1 /* OPENBSD ORIGINAL: lib/libc/stdlib/setenv.c */ 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. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include "includes.h" 33 #if !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV) 34 35 #if defined(LIBC_SCCS) && !defined(lint) 36 static char *rcsid = "$OpenBSD: setenv.c,v 1.6 2003/06/02 20:18:38 millert Exp $"; 37 #endif /* LIBC_SCCS and not lint */ 38 39 #include <stdlib.h> 40 #include <string.h> 41 42 char *__findenv(const char *name, int *offset); 43 44 /* 45 * __findenv -- 46 * Returns pointer to value associated with name, if any, else NULL. 47 * Sets offset to be the offset of the name/value combination in the 48 * environmental array, for use by setenv(3) and unsetenv(3). 49 * Explicitly removes '=' in argument name. 50 * 51 * This routine *should* be a static; don't use it. 52 */ 53 char * 54 __findenv(name, offset) 55 register const char *name; 56 int *offset; 57 { 58 extern char **environ; 59 register int len, i; 60 register const char *np; 61 register char **p, *cp; 62 63 if (name == NULL || environ == NULL) 64 return (NULL); 65 for (np = name; *np && *np != '='; ++np) 66 ; 67 len = np - name; 68 for (p = environ; (cp = *p) != NULL; ++p) { 69 for (np = name, i = len; i && *cp; i--) 70 if (*cp++ != *np++) 71 break; 72 if (i == 0 && *cp++ == '=') { 73 *offset = p - environ; 74 return (cp); 75 } 76 } 77 return (NULL); 78 } 79 80 #ifndef HAVE_SETENV 81 /* 82 * setenv -- 83 * Set the value of the environmental variable "name" to be 84 * "value". If rewrite is set, replace any current value. 85 */ 86 int 87 setenv(name, value, rewrite) 88 register const char *name; 89 register const char *value; 90 int rewrite; 91 { 92 extern char **environ; 93 static int alloced; /* if allocated space before */ 94 register char *C; 95 int l_value, offset; 96 97 if (*value == '=') /* no `=' in value */ 98 ++value; 99 l_value = strlen(value); 100 if ((C = __findenv(name, &offset))) { /* find if already exists */ 101 if (!rewrite) 102 return (0); 103 if (strlen(C) >= l_value) { /* old larger; copy over */ 104 while ((*C++ = *value++)) 105 ; 106 return (0); 107 } 108 } else { /* create new slot */ 109 register int cnt; 110 register char **P; 111 112 for (P = environ, cnt = 0; *P; ++P, ++cnt); 113 if (alloced) { /* just increase size */ 114 P = (char **)realloc((void *)environ, 115 (size_t)(sizeof(char *) * (cnt + 2))); 116 if (!P) 117 return (-1); 118 environ = P; 119 } 120 else { /* get new space */ 121 alloced = 1; /* copy old entries into it */ 122 P = (char **)malloc((size_t)(sizeof(char *) * 123 (cnt + 2))); 124 if (!P) 125 return (-1); 126 memmove(P, environ, cnt * sizeof(char *)); 127 environ = P; 128 } 129 environ[cnt + 1] = NULL; 130 offset = cnt; 131 } 132 for (C = (char *)name; *C && *C != '='; ++C); /* no `=' in name */ 133 if (!(environ[offset] = /* name + `=' + value */ 134 malloc((size_t)((int)(C - name) + l_value + 2)))) 135 return (-1); 136 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 137 ; 138 for (*C++ = '='; (*C++ = *value++); ) 139 ; 140 return (0); 141 } 142 #endif /* HAVE_SETENV */ 143 144 #ifndef HAVE_UNSETENV 145 /* 146 * unsetenv(name) -- 147 * Delete environmental variable "name". 148 */ 149 void 150 unsetenv(name) 151 const char *name; 152 { 153 extern char **environ; 154 register char **P; 155 int offset; 156 char *__findenv(); 157 158 while (__findenv(name, &offset)) /* if set multiple times */ 159 for (P = &environ[offset];; ++P) 160 if (!(*P = *(P + 1))) 161 break; 162 } 163 #endif /* HAVE_UNSETENV */ 164 165 #endif /* !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV) */ 166