1 /* $OpenBSD: setenv.c,v 1.20 2022/08/08 22:40:03 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 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 == str || *cp != '=') { 52 /* '=' is the first character of string or is missing. */ 53 errno = EINVAL; 54 return (-1); 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 if (environ != NULL) { 70 for (P = environ; *P != NULL; P++) 71 ; 72 cnt = P - environ; 73 } 74 P = reallocarray(lastenv, cnt + 2, sizeof(char *)); 75 if (!P) 76 return (-1); 77 if (lastenv != environ && environ != NULL) 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 DEF_WEAK(putenv); 85 86 /* 87 * setenv -- 88 * Set the value of the environmental variable "name" to be 89 * "value". If rewrite is set, replace any current value. 90 */ 91 int 92 setenv(const char *name, const char *value, int rewrite) 93 { 94 char *C, **P; 95 const char *np; 96 int l_value, offset = 0; 97 98 if (!name || !*name) { 99 errno = EINVAL; 100 return (-1); 101 } 102 for (np = name; *np && *np != '='; ++np) 103 ; 104 if (*np) { 105 errno = EINVAL; 106 return (-1); /* has `=' in name */ 107 } 108 109 l_value = strlen(value); 110 if ((C = __findenv(name, (int)(np - name), &offset)) != NULL) { 111 int tmpoff = offset + 1; 112 if (!rewrite) 113 return (0); 114 #if 0 /* XXX - existing entry may not be writable */ 115 if (strlen(C) >= l_value) { /* old larger; copy over */ 116 while ((*C++ = *value++)) 117 ; 118 return (0); 119 } 120 #endif 121 /* could be set multiple times */ 122 while (__findenv(name, (int)(np - name), &tmpoff)) { 123 for (P = &environ[tmpoff];; ++P) 124 if (!(*P = *(P + 1))) 125 break; 126 } 127 } else { /* create new slot */ 128 size_t cnt = 0; 129 130 if (environ != NULL) { 131 for (P = environ; *P != NULL; P++) 132 ; 133 cnt = P - environ; 134 } 135 P = reallocarray(lastenv, cnt + 2, sizeof(char *)); 136 if (!P) 137 return (-1); 138 if (lastenv != environ && environ != NULL) 139 memcpy(P, environ, cnt * sizeof(char *)); 140 lastenv = environ = P; 141 offset = cnt; 142 environ[cnt + 1] = NULL; 143 } 144 if (!(environ[offset] = /* name + `=' + value */ 145 malloc((int)(np - name) + l_value + 2))) 146 return (-1); 147 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) 148 ; 149 for (*C++ = '='; (*C++ = *value++); ) 150 ; 151 return (0); 152 } 153 DEF_WEAK(setenv); 154 155 /* 156 * unsetenv(name) -- 157 * Delete environmental variable "name". 158 */ 159 int 160 unsetenv(const char *name) 161 { 162 char **P; 163 const char *np; 164 int offset = 0; 165 166 if (!name || !*name) { 167 errno = EINVAL; 168 return (-1); 169 } 170 for (np = name; *np && *np != '='; ++np) 171 ; 172 if (*np) { 173 errno = EINVAL; 174 return (-1); /* has `=' in name */ 175 } 176 177 /* could be set multiple times */ 178 while (__findenv(name, (int)(np - name), &offset)) { 179 for (P = &environ[offset];; ++P) 180 if (!(*P = *(P + 1))) 181 break; 182 } 183 return (0); 184 } 185 DEF_WEAK(unsetenv); 186