1/* $OpenBSD: setenv.c,v 1.16 2015/09/13 08:31:47 guenther 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 35extern char **environ; 36static char **lastenv; /* last value of environ */ 37 38/* 39 * putenv -- 40 * Add a name=value string directly to the environmental, replacing 41 * any current value. 42 */ 43int 44putenv(char *str) 45{ 46 char **P, *cp; 47 size_t cnt; 48 int offset = 0; 49 50 for (cp = str; *cp && *cp != '='; ++cp) 51 ; 52 if (*cp != '=') { 53 errno = EINVAL; 54 return (-1); /* missing `=' in string */ 55 } 56 57 if (__findenv(str, (int)(cp - str), &offset) != NULL) { 58 environ[offset++] = str; 59 /* could be set multiple times */ 60 while (__findenv(str, (int)(cp - str), &offset)) { 61 for (P = &environ[offset];; ++P) 62 if (!(*P = *(P + 1))) 63 break; 64 } 65 return (0); 66 } 67 68 /* create new slot for string */ 69 for (P = environ; *P != NULL; P++) 70 ; 71 cnt = P - environ; 72 P = reallocarray(lastenv, cnt + 2, sizeof(char *)); 73 if (!P) 74 return (-1); 75 if (lastenv != environ) 76 memcpy(P, environ, cnt * sizeof(char *)); 77 lastenv = environ = P; 78 environ[cnt] = str; 79 environ[cnt + 1] = NULL; 80 return (0); 81} 82DEF_WEAK(putenv); 83 84/* 85 * setenv -- 86 * Set the value of the environmental variable "name" to be 87 * "value". If rewrite is set, replace any current value. 88 */ 89int 90setenv(const char *name, const char *value, int rewrite) 91{ 92 char *C, **P; 93 const char *np; 94 int l_value, offset = 0; 95 96 if (!name || !*name) { 97 errno = EINVAL; 98 return (-1); 99 } 100 for (np = name; *np && *np != '='; ++np) 101 ; 102 if (*np) { 103 errno = EINVAL; 104 return (-1); /* has `=' in name */ 105 } 106 107 l_value = strlen(value); 108 if ((C = __findenv(name, (int)(np - name), &offset)) != NULL) { 109 int tmpoff = offset + 1; 110 if (!rewrite) 111 return (0); 112#if 0 /* XXX - existing entry may not be writable */ 113 if (strlen(C) >= l_value) { /* old larger; copy over */ 114 while ((*C++ = *value++)) 115 ; 116 return (0); 117 } 118#endif 119 /* could be set multiple times */ 120 while (__findenv(name, (int)(np - name), &tmpoff)) { 121 for (P = &environ[tmpoff];; ++P) 122 if (!(*P = *(P + 1))) 123 break; 124 } 125 } else { /* create new slot */ 126 size_t cnt; 127 128 for (P = environ; *P != NULL; P++) 129 ; 130 cnt = P - environ; 131 P = reallocarray(lastenv, cnt + 2, sizeof(char *)); 132 if (!P) 133 return (-1); 134 if (lastenv != environ) 135 memcpy(P, environ, cnt * sizeof(char *)); 136 lastenv = environ = P; 137 offset = cnt; 138 environ[cnt + 1] = NULL; 139 } 140 if (!(environ[offset] = /* name + `=' + value */ 141 malloc((size_t)((int)(np - name) + l_value + 2)))) 142 return (-1); 143 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 144 ; 145 for (*C++ = '='; (*C++ = *value++); ) 146 ; 147 return (0); 148} 149DEF_WEAK(setenv); 150 151/* 152 * unsetenv(name) -- 153 * Delete environmental variable "name". 154 */ 155int 156unsetenv(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} 181DEF_WEAK(unsetenv); 182