| 1 | /* Copyright (C) 1991, 1994, 1997-1998, 2000, 2003-2013 Free Software |
| 2 | Foundation, Inc. |
| 3 | |
| 4 | NOTE: The canonical source of this file is maintained with the GNU C |
| 5 | Library. Bugs can be reported to bug-glibc@prep.ai.mit.edu. |
| 6 | |
| 7 | This program is free software: you can redistribute it and/or modify it |
| 8 | under the terms of the GNU Lesser General Public License as published by the |
| 9 | Free Software Foundation; either version 3 of the License, or any |
| 10 | later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU Lesser General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU Lesser General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include <config.h> |
| 21 | |
| 22 | /* Specification. */ |
| 23 | #include <stdlib.h> |
| 24 | |
| 25 | #include <stddef.h> |
| 26 | |
| 27 | /* Include errno.h *after* sys/types.h to work around header problems |
| 28 | on AIX 3.2.5. */ |
| 29 | #include <errno.h> |
| 30 | #ifndef __set_errno |
| 31 | # define __set_errno(ev) ((errno) = (ev)) |
| 32 | #endif |
| 33 | |
| 34 | #include <string.h> |
| 35 | #include <unistd.h> |
| 36 | |
| 37 | #if _LIBC |
| 38 | # if HAVE_GNU_LD |
| 39 | # define environ __environ |
| 40 | # else |
| 41 | extern char **environ; |
| 42 | # endif |
| 43 | #endif |
| 44 | |
| 45 | #if _LIBC |
| 46 | /* This lock protects against simultaneous modifications of 'environ'. */ |
| 47 | # include <bits/libc-lock.h> |
| 48 | __libc_lock_define_initialized (static, envlock) |
| 49 | # define LOCK __libc_lock_lock (envlock) |
| 50 | # define UNLOCK __libc_lock_unlock (envlock) |
| 51 | #else |
| 52 | # define LOCK |
| 53 | # define UNLOCK |
| 54 | #endif |
| 55 | |
| 56 | static int |
| 57 | _unsetenv (const char *name) |
| 58 | { |
| 59 | size_t len; |
| 60 | char **ep; |
| 61 | |
| 62 | if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) |
| 63 | { |
| 64 | __set_errno (EINVAL); |
| 65 | return -1; |
| 66 | } |
| 67 | |
| 68 | len = strlen (name); |
| 69 | |
| 70 | LOCK; |
| 71 | |
| 72 | ep = environ; |
| 73 | while (*ep != NULL) |
| 74 | if (!strncmp (*ep, name, len) && (*ep)[len] == '=') |
| 75 | { |
| 76 | /* Found it. Remove this pointer by moving later ones back. */ |
| 77 | char **dp = ep; |
| 78 | |
| 79 | do |
| 80 | dp[0] = dp[1]; |
| 81 | while (*dp++); |
| 82 | /* Continue the loop in case NAME appears again. */ |
| 83 | } |
| 84 | else |
| 85 | ++ep; |
| 86 | |
| 87 | UNLOCK; |
| 88 | |
| 89 | return 0; |
| 90 | } |
| 91 | |
| 92 | |
| 93 | /* Put STRING, which is of the form "NAME=VALUE", in the environment. |
| 94 | If STRING contains no '=', then remove STRING from the environment. */ |
| 95 | int |
| 96 | putenv (char *string) |
| 97 | { |
| 98 | const char *const name_end = strchr (string, '='); |
| 99 | register size_t size; |
| 100 | register char **ep; |
| 101 | |
| 102 | if (name_end == NULL) |
| 103 | { |
| 104 | /* Remove the variable from the environment. */ |
| 105 | return _unsetenv (string); |
| 106 | } |
| 107 | |
| 108 | size = 0; |
| 109 | for (ep = environ; *ep != NULL; ++ep) |
| 110 | if (!strncmp (*ep, string, name_end - string) && |
| 111 | (*ep)[name_end - string] == '=') |
| 112 | break; |
| 113 | else |
| 114 | ++size; |
| 115 | |
| 116 | if (*ep == NULL) |
| 117 | { |
| 118 | #if HAVE__PUTENV |
| 119 | /* Rely on _putenv to allocate the new environment. If other |
| 120 | parts of the application use _putenv, the !HAVE__PUTENV code |
| 121 | would fight over who owns the environ vector, causing a crash. */ |
| 122 | if (name_end[1]) |
| 123 | return _putenv (string); |
| 124 | else |
| 125 | { |
| 126 | /* _putenv ("NAME=") unsets NAME, so invoke _putenv ("NAME=x") |
| 127 | to allocate the environ vector and then replace the new |
| 128 | entry with "NAME=". */ |
| 129 | int putenv_result, putenv_errno; |
| 130 | char *name_x = malloc (name_end - string + sizeof "=x"); |
| 131 | if (!name_x) |
| 132 | return -1; |
| 133 | memcpy (name_x, string, name_end - string + 1); |
| 134 | name_x[name_end - string + 1] = 'x'; |
| 135 | name_x[name_end - string + 2] = 0; |
| 136 | putenv_result = _putenv (name_x); |
| 137 | putenv_errno = errno; |
| 138 | for (ep = environ; *ep; ep++) |
| 139 | if (*ep == name_x) |
| 140 | { |
| 141 | *ep = string; |
| 142 | break; |
| 143 | } |
| 144 | free (name_x); |
| 145 | __set_errno (putenv_errno); |
| 146 | return putenv_result; |
| 147 | } |
| 148 | #else |
| 149 | static char **last_environ = NULL; |
| 150 | char **new_environ = (char **) malloc ((size + 2) * sizeof (char *)); |
| 151 | if (new_environ == NULL) |
| 152 | return -1; |
| 153 | (void) memcpy ((void *) new_environ, (void *) environ, |
| 154 | size * sizeof (char *)); |
| 155 | new_environ[size] = (char *) string; |
| 156 | new_environ[size + 1] = NULL; |
| 157 | free (last_environ); |
| 158 | last_environ = new_environ; |
| 159 | environ = new_environ; |
| 160 | #endif |
| 161 | } |
| 162 | else |
| 163 | *ep = string; |
| 164 | |
| 165 | return 0; |
| 166 | } |