| 1 | /* Copyright (C) 1992,1995-1999,2000-2002,2005-2006 Free Software Foundation, Inc.
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| 2 | This file is part of the GNU C Library.
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| 3 |
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| 4 | This program is free software; you can redistribute it and/or modify
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| 5 | it under the terms of the GNU General Public License as published by
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| 6 | the Free Software Foundation; either version 2, or (at your option)
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| 7 | any later version.
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| 8 |
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| 9 | This program is distributed in the hope that it will be useful,
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 12 | GNU General Public License for more details.
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| 13 |
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| 14 | You should have received a copy of the GNU General Public License along
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| 15 | with this program; if not, write to the Free Software Foundation,
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| 16 | Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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| 17 |
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| 18 | #include <config.h>
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| 19 |
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| 20 | #include <errno.h>
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| 21 | #if !_LIBC
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| 22 | # define __set_errno(ev) ((errno) = (ev))
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| 23 | #endif
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| 24 |
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| 25 | #include <stdlib.h>
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| 26 | #include <string.h>
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| 27 | #include <unistd.h>
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| 28 |
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| 29 | #if !_LIBC
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| 30 | # define __environ environ
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| 31 | # ifndef HAVE_ENVIRON_DECL
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| 32 | extern char **environ;
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| 33 | # endif
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| 34 | #endif
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| 35 |
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| 36 | #if _LIBC
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| 37 | /* This lock protects against simultaneous modifications of `environ'. */
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| 38 | # include <bits/libc-lock.h>
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| 39 | __libc_lock_define_initialized (static, envlock)
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| 40 | # define LOCK __libc_lock_lock (envlock)
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| 41 | # define UNLOCK __libc_lock_unlock (envlock)
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| 42 | #else
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| 43 | # define LOCK
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| 44 | # define UNLOCK
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| 45 | #endif
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| 46 |
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| 47 | /* In the GNU C library we must keep the namespace clean. */
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| 48 | #ifdef _LIBC
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| 49 | # define unsetenv __unsetenv
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| 50 | #endif
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| 51 |
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| 52 |
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| 53 | int
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| 54 | unsetenv (const char *name)
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| 55 | {
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| 56 | size_t len;
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| 57 | char **ep;
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| 58 |
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| 59 | if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
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| 60 | {
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| 61 | __set_errno (EINVAL);
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| 62 | return -1;
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| 63 | }
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| 64 |
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| 65 | len = strlen (name);
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| 66 |
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| 67 | LOCK;
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| 68 |
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| 69 | ep = __environ;
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| 70 | while (*ep != NULL)
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| 71 | if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
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| 72 | {
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| 73 | /* Found it. Remove this pointer by moving later ones back. */
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| 74 | char **dp = ep;
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| 75 |
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| 76 | do
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| 77 | dp[0] = dp[1];
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| 78 | while (*dp++);
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| 79 | /* Continue the loop in case NAME appears again. */
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| 80 | }
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| 81 | else
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| 82 | ++ep;
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| 83 |
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| 84 | UNLOCK;
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| 85 |
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| 86 | return 0;
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| 87 | }
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| 88 |
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| 89 | #ifdef _LIBC
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| 90 | # undef unsetenv
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| 91 | weak_alias (__unsetenv, unsetenv)
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| 92 | #endif
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