1 /* $OpenBSD: setenv.c,v 1.14 2012/09/23 16:08:04 jeremy Exp $ */ 2 /* 3 * Copyright (c) 1987 Regents of the University of California. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <errno.h> 32 #include <stdlib.h> 33 #include <string.h> 34 35 char *__findenv(const char *name, int len, int *offset); 36 37 extern char **environ; 38 static char **lastenv; /* last value of environ */ 39 40 /* 41 * putenv -- 42 * Add a name=value string directly to the environmental, replacing 43 * any current value. 44 */ 45 int 46 putenv(char *str) 47 { 48 char **P, *cp; 49 size_t cnt; 50 int offset = 0; 51 52 for (cp = str; *cp && *cp != '='; ++cp) 53 ; 54 if (*cp != '=') { 55 errno = EINVAL; 56 return (-1); /* missing `=' in string */ 57 } 58 59 if (__findenv(str, (int)(cp - str), &offset) != NULL) { 60 environ[offset++] = str; 61 /* could be set multiple times */ 62 while (__findenv(str, (int)(cp - str), &offset)) { 63 for (P = &environ[offset];; ++P) 64 if (!(*P = *(P + 1))) 65 break; 66 } 67 return (0); 68 } 69 70 /* create new slot for string */ 71 for (P = environ; *P != NULL; P++) 72 ; 73 cnt = P - environ; 74 P = (char **)realloc(lastenv, sizeof(char *) * (cnt + 2)); 75 if (!P) 76 return (-1); 77 if (lastenv != environ) 78 memcpy(P, environ, cnt * sizeof(char *)); 79 lastenv = environ = P; 80 environ[cnt] = str; 81 environ[cnt + 1] = NULL; 82 return (0); 83 } 84 85 /* 86 * setenv -- 87 * Set the value of the environmental variable "name" to be 88 * "value". If rewrite is set, replace any current value. 89 */ 90 int 91 setenv(const char *name, const char *value, int rewrite) 92 { 93 char *C, **P; 94 const char *np; 95 int l_value, offset = 0; 96 97 if (!name || !*name) { 98 errno = EINVAL; 99 return (-1); 100 } 101 for (np = name; *np && *np != '='; ++np) 102 ; 103 if (*np) { 104 errno = EINVAL; 105 return (-1); /* has `=' in name */ 106 } 107 108 l_value = strlen(value); 109 if ((C = __findenv(name, (int)(np - name), &offset)) != NULL) { 110 int tmpoff = offset + 1; 111 if (!rewrite) 112 return (0); 113 #if 0 /* XXX - existing entry may not be writable */ 114 if (strlen(C) >= l_value) { /* old larger; copy over */ 115 while ((*C++ = *value++)) 116 ; 117 return (0); 118 } 119 #endif 120 /* could be set multiple times */ 121 while (__findenv(name, (int)(np - name), &tmpoff)) { 122 for (P = &environ[tmpoff];; ++P) 123 if (!(*P = *(P + 1))) 124 break; 125 } 126 } else { /* create new slot */ 127 size_t cnt; 128 129 for (P = environ; *P != NULL; P++) 130 ; 131 cnt = P - environ; 132 P = (char **)realloc(lastenv, sizeof(char *) * (cnt + 2)); 133 if (!P) 134 return (-1); 135 if (lastenv != environ) 136 memcpy(P, environ, cnt * sizeof(char *)); 137 lastenv = environ = P; 138 offset = cnt; 139 environ[cnt + 1] = NULL; 140 } 141 if (!(environ[offset] = /* name + `=' + value */ 142 malloc((size_t)((int)(np - name) + l_value + 2)))) 143 return (-1); 144 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 145 ; 146 for (*C++ = '='; (*C++ = *value++); ) 147 ; 148 return (0); 149 } 150 151 /* 152 * unsetenv(name) -- 153 * Delete environmental variable "name". 154 */ 155 int 156 unsetenv(const char *name) 157 { 158 char **P; 159 const char *np; 160 int offset = 0; 161 162 if (!name || !*name) { 163 errno = EINVAL; 164 return (-1); 165 } 166 for (np = name; *np && *np != '='; ++np) 167 ; 168 if (*np) { 169 errno = EINVAL; 170 return (-1); /* has `=' in name */ 171 } 172 173 /* could be set multiple times */ 174 while (__findenv(name, (int)(np - name), &offset)) { 175 for (P = &environ[offset];; ++P) 176 if (!(*P = *(P + 1))) 177 break; 178 } 179 return (0); 180 } 181