mirror of
https://github.com/coreutils/coreutils.git
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98 lines
2.2 KiB
C
98 lines
2.2 KiB
C
/* Copyright (C) 1992,1995-1999,2000-2002,2005 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <errno.h>
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#if !_LIBC
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# if !defined errno && !defined HAVE_ERRNO_DECL
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extern int errno;
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# endif
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# define __set_errno(ev) ((errno) = (ev))
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#if !_LIBC
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# define __environ environ
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# ifndef HAVE_ENVIRON_DECL
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extern char **environ;
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# endif
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#endif
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#if _LIBC
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/* This lock protects against simultaneous modifications of `environ'. */
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# include <bits/libc-lock.h>
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__libc_lock_define_initialized (static, envlock)
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# define LOCK __libc_lock_lock (envlock)
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# define UNLOCK __libc_lock_unlock (envlock)
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#else
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# define LOCK
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# define UNLOCK
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#endif
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/* In the GNU C library we must keep the namespace clean. */
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#ifdef _LIBC
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# define unsetenv __unsetenv
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#endif
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int
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unsetenv (const char *name)
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{
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size_t len;
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char **ep;
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if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
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{
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__set_errno (EINVAL);
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return -1;
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}
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len = strlen (name);
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LOCK;
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ep = __environ;
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while (*ep != NULL)
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if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
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{
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/* Found it. Remove this pointer by moving later ones back. */
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char **dp = ep;
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do
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dp[0] = dp[1];
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while (*dp++);
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/* Continue the loop in case NAME appears again. */
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}
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else
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++ep;
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UNLOCK;
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return 0;
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}
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#ifdef _LIBC
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# undef unsetenv
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weak_alias (__unsetenv, unsetenv)
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#endif
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