1 /* $OpenBSD: setenv.c,v 1.13 2010/08/23 22:31:50 millert 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 for (np = name; *np && *np != '='; ++np) 98 ; 99 #ifdef notyet 100 if (*np) { 101 errno = EINVAL; 102 return (-1); /* has `=' in name */ 103 } 104 #endif 105 106 l_value = strlen(value); 107 if ((C = __findenv(name, (int)(np - name), &offset)) != NULL) { 108 int tmpoff = offset + 1; 109 if (!rewrite) 110 return (0); 111 #if 0 /* XXX - existing entry may not be writable */ 112 if (strlen(C) >= l_value) { /* old larger; copy over */ 113 while ((*C++ = *value++)) 114 ; 115 return (0); 116 } 117 #endif 118 /* could be set multiple times */ 119 while (__findenv(name, (int)(np - name), &tmpoff)) { 120 for (P = &environ[tmpoff];; ++P) 121 if (!(*P = *(P + 1))) 122 break; 123 } 124 } else { /* create new slot */ 125 size_t cnt; 126 127 for (P = environ; *P != NULL; P++) 128 ; 129 cnt = P - environ; 130 P = (char **)realloc(lastenv, sizeof(char *) * (cnt + 2)); 131 if (!P) 132 return (-1); 133 if (lastenv != environ) 134 memcpy(P, environ, cnt * sizeof(char *)); 135 lastenv = environ = P; 136 offset = cnt; 137 environ[cnt + 1] = NULL; 138 } 139 if (!(environ[offset] = /* name + `=' + value */ 140 malloc((size_t)((int)(np - name) + l_value + 2)))) 141 return (-1); 142 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 143 ; 144 for (*C++ = '='; (*C++ = *value++); ) 145 ; 146 return (0); 147 } 148 149 /* 150 * unsetenv(name) -- 151 * Delete environmental variable "name". 152 */ 153 int 154 unsetenv(const char *name) 155 { 156 char **P; 157 const char *np; 158 int offset = 0; 159 160 if (!name || !*name) { 161 errno = EINVAL; 162 return (-1); 163 } 164 for (np = name; *np && *np != '='; ++np) 165 ; 166 if (*np) { 167 errno = EINVAL; 168 return (-1); /* has `=' in name */ 169 } 170 171 /* could be set multiple times */ 172 while (__findenv(name, (int)(np - name), &offset)) { 173 for (P = &environ[offset];; ++P) 174 if (!(*P = *(P + 1))) 175 break; 176 } 177 return (0); 178 } 179