1 /* Copyright (C) 1992-2018 Free Software Foundation, Inc. 2 This file based on setenv.c in the GNU C Library. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Library General Public License as 6 published by the Free Software Foundation; either version 2 of the 7 License, or (at your option) any later version. 8 9 The GNU C Library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Library General Public License for more details. 13 14 You should have received a copy of the GNU Library General Public 15 License along with the GNU C Library; see the file COPYING.LIB. If not, 16 write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, 17 Boston, MA 02110-1301, USA. */ 18 19 20 /* 21 22 @deftypefn Supplemental int setenv (const char *@var{name}, @ 23 const char *@var{value}, int @var{overwrite}) 24 @deftypefnx Supplemental void unsetenv (const char *@var{name}) 25 26 @code{setenv} adds @var{name} to the environment with value 27 @var{value}. If the name was already present in the environment, 28 the new value will be stored only if @var{overwrite} is nonzero. 29 The companion @code{unsetenv} function removes @var{name} from the 30 environment. This implementation is not safe for multithreaded code. 31 32 @end deftypefn 33 34 */ 35 36 #if HAVE_CONFIG_H 37 # include <config.h> 38 #endif 39 40 #define setenv libiberty_setenv 41 #define unsetenv libiberty_unsetenv 42 43 #include "ansidecl.h" 44 #include <sys/types.h> /* For `size_t' */ 45 #include <stdio.h> /* For `NULL' */ 46 47 #include <errno.h> 48 #if !defined(errno) && !defined(HAVE_ERRNO_DECL) 49 extern int errno; 50 #endif 51 #define __set_errno(ev) ((errno) = (ev)) 52 53 #if HAVE_STDLIB_H 54 # include <stdlib.h> 55 #endif 56 #if HAVE_STRING_H 57 # include <string.h> 58 #endif 59 #if HAVE_UNISTD_H 60 # include <unistd.h> 61 #endif 62 63 #define __environ environ 64 #include "environ.h" 65 66 #undef setenv 67 #undef unsetenv 68 69 /* LOCK and UNLOCK are defined as no-ops. This makes the libiberty 70 * implementation MT-Unsafe. */ 71 #define LOCK 72 #define UNLOCK 73 74 /* Below this point, it's verbatim code from the glibc-2.0 implementation */ 75 76 /* If this variable is not a null pointer we allocated the current 77 environment. */ 78 static char **last_environ; 79 80 81 int 82 setenv (const char *name, const char *value, int replace) 83 { 84 register char **ep = 0; 85 register size_t size; 86 const size_t namelen = strlen (name); 87 const size_t vallen = strlen (value) + 1; 88 89 LOCK; 90 91 size = 0; 92 if (__environ != NULL) 93 { 94 for (ep = __environ; *ep != NULL; ++ep) 95 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=') 96 break; 97 else 98 ++size; 99 } 100 101 if (__environ == NULL || *ep == NULL) 102 { 103 char **new_environ; 104 if (__environ == last_environ && __environ != NULL) 105 /* We allocated this space; we can extend it. */ 106 new_environ = (char **) realloc (last_environ, 107 (size + 2) * sizeof (char *)); 108 else 109 new_environ = (char **) malloc ((size + 2) * sizeof (char *)); 110 111 if (new_environ == NULL) 112 { 113 UNLOCK; 114 return -1; 115 } 116 117 new_environ[size] = (char *) malloc (namelen + 1 + vallen); 118 if (new_environ[size] == NULL) 119 { 120 free ((char *) new_environ); 121 __set_errno (ENOMEM); 122 UNLOCK; 123 return -1; 124 } 125 126 if (__environ != last_environ) 127 memcpy ((char *) new_environ, (char *) __environ, 128 size * sizeof (char *)); 129 130 memcpy (new_environ[size], name, namelen); 131 new_environ[size][namelen] = '='; 132 memcpy (&new_environ[size][namelen + 1], value, vallen); 133 134 new_environ[size + 1] = NULL; 135 136 last_environ = __environ = new_environ; 137 } 138 else if (replace) 139 { 140 size_t len = strlen (*ep); 141 if (len + 1 < namelen + 1 + vallen) 142 { 143 /* The existing string is too short; malloc a new one. */ 144 char *new_string = (char *) malloc (namelen + 1 + vallen); 145 if (new_string == NULL) 146 { 147 UNLOCK; 148 return -1; 149 } 150 *ep = new_string; 151 } 152 memcpy (*ep, name, namelen); 153 (*ep)[namelen] = '='; 154 memcpy (&(*ep)[namelen + 1], value, vallen); 155 } 156 157 UNLOCK; 158 159 return 0; 160 } 161 162 void 163 unsetenv (const char *name) 164 { 165 const size_t len = strlen (name); 166 char **ep; 167 168 LOCK; 169 170 for (ep = __environ; *ep; ++ep) 171 if (!strncmp (*ep, name, len) && (*ep)[len] == '=') 172 { 173 /* Found it. Remove this pointer by moving later ones back. */ 174 char **dp = ep; 175 do 176 dp[0] = dp[1]; 177 while (*dp++); 178 /* Continue the loop in case NAME appears again. */ 179 } 180 181 UNLOCK; 182 } 183