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| 1 /* Copyright (C) 1992,1995-1999,2000-2002,2005-2008 Free Software Foundation, In
c. |
| 2 This file is part of the GNU C Library. |
| 3 |
| 4 This program is free software: you can redistribute it and/or modify |
| 5 it under the terms of the GNU General Public License as published by |
| 6 the Free Software Foundation; either version 3 of the License, or |
| 7 (at your option) any later version. |
| 8 |
| 9 This program 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 |
| 12 GNU General Public License for more details. |
| 13 |
| 14 You should have received a copy of the GNU General Public License |
| 15 along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 16 |
| 17 #include <config.h> |
| 18 |
| 19 /* Specification. */ |
| 20 #include <stdlib.h> |
| 21 |
| 22 #include <errno.h> |
| 23 #if !_LIBC |
| 24 # define __set_errno(ev) ((errno) = (ev)) |
| 25 #endif |
| 26 |
| 27 #include <string.h> |
| 28 #include <unistd.h> |
| 29 |
| 30 #if !_LIBC |
| 31 # define __environ environ |
| 32 #endif |
| 33 |
| 34 #if _LIBC |
| 35 /* This lock protects against simultaneous modifications of `environ'. */ |
| 36 # include <bits/libc-lock.h> |
| 37 __libc_lock_define_initialized (static, envlock) |
| 38 # define LOCK __libc_lock_lock (envlock) |
| 39 # define UNLOCK __libc_lock_unlock (envlock) |
| 40 #else |
| 41 # define LOCK |
| 42 # define UNLOCK |
| 43 #endif |
| 44 |
| 45 /* In the GNU C library we must keep the namespace clean. */ |
| 46 #ifdef _LIBC |
| 47 # define unsetenv __unsetenv |
| 48 #endif |
| 49 |
| 50 |
| 51 int |
| 52 unsetenv (const char *name) |
| 53 { |
| 54 size_t len; |
| 55 char **ep; |
| 56 |
| 57 if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) |
| 58 { |
| 59 __set_errno (EINVAL); |
| 60 return -1; |
| 61 } |
| 62 |
| 63 len = strlen (name); |
| 64 |
| 65 LOCK; |
| 66 |
| 67 ep = __environ; |
| 68 while (*ep != NULL) |
| 69 if (!strncmp (*ep, name, len) && (*ep)[len] == '=') |
| 70 { |
| 71 /* Found it. Remove this pointer by moving later ones back. */ |
| 72 char **dp = ep; |
| 73 |
| 74 do |
| 75 dp[0] = dp[1]; |
| 76 while (*dp++); |
| 77 /* Continue the loop in case NAME appears again. */ |
| 78 } |
| 79 else |
| 80 ++ep; |
| 81 |
| 82 UNLOCK; |
| 83 |
| 84 return 0; |
| 85 } |
| 86 |
| 87 #ifdef _LIBC |
| 88 # undef unsetenv |
| 89 weak_alias (__unsetenv, unsetenv) |
| 90 #endif |
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