1 /* $OpenBSD: setenv.c,v 1.19 2016/09/21 04:38:56 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 35 static char **lastenv; /* last value of environ */ 36 37 /* 38 * putenv -- 39 * Add a name=value string directly to the environmental, replacing 40 * any current value. 41 */ 42 int 43 putenv(char *str) 44 { 45 char **P, *cp; 46 size_t cnt = 0; 47 int offset = 0; 48 49 for (cp = str; *cp && *cp != '='; ++cp) 50 ; 51 if (*cp != '=') { 52 errno = EINVAL; 53 return (-1); /* missing `=' in string */ 54 } 55 56 if (__findenv(str, (int)(cp - str), &offset) != NULL) { 57 environ[offset++] = str; 58 /* could be set multiple times */ 59 while (__findenv(str, (int)(cp - str), &offset)) { 60 for (P = &environ[offset];; ++P) 61 if (!(*P = *(P + 1))) 62 break; 63 } 64 return (0); 65 } 66 67 /* create new slot for string */ 68 if (environ != NULL) { 69 for (P = environ; *P != NULL; P++) 70 ; 71 cnt = P - environ; 72 } 73 P = reallocarray(lastenv, cnt + 2, sizeof(char *)); 74 if (!P) 75 return (-1); 76 if (lastenv != environ && environ != NULL) 77 memcpy(P, environ, cnt * sizeof(char *)); 78 lastenv = environ = P; 79 environ[cnt] = str; 80 environ[cnt + 1] = NULL; 81 return (0); 82 } 83 DEF_WEAK(putenv); 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 = 0; 128 129 if (environ != NULL) { 130 for (P = environ; *P != NULL; P++) 131 ; 132 cnt = P - environ; 133 } 134 P = reallocarray(lastenv, cnt + 2, sizeof(char *)); 135 if (!P) 136 return (-1); 137 if (lastenv != environ && environ != NULL) 138 memcpy(P, environ, cnt * sizeof(char *)); 139 lastenv = environ = P; 140 offset = cnt; 141 environ[cnt + 1] = NULL; 142 } 143 if (!(environ[offset] = /* name + `=' + value */ 144 malloc((int)(np - name) + l_value + 2))) 145 return (-1); 146 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 147 ; 148 for (*C++ = '='; (*C++ = *value++); ) 149 ; 150 return (0); 151 } 152 DEF_WEAK(setenv); 153 154 /* 155 * unsetenv(name) -- 156 * Delete environmental variable "name". 157 */ 158 int 159 unsetenv(const char *name) 160 { 161 char **P; 162 const char *np; 163 int offset = 0; 164 165 if (!name || !*name) { 166 errno = EINVAL; 167 return (-1); 168 } 169 for (np = name; *np && *np != '='; ++np) 170 ; 171 if (*np) { 172 errno = EINVAL; 173 return (-1); /* has `=' in name */ 174 } 175 176 /* could be set multiple times */ 177 while (__findenv(name, (int)(np - name), &offset)) { 178 for (P = &environ[offset];; ++P) 179 if (!(*P = *(P + 1))) 180 break; 181 } 182 return (0); 183 } 184 DEF_WEAK(unsetenv); 185