128 lines
2.8 KiB
C
128 lines
2.8 KiB
C
/* Copyright (C) 1992, 1995-2002, 2005-2016 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 3 of the License, or
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(at your option) 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
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc
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optimizes away the name == NULL test below. */
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#define _GL_ARG_NONNULL(params)
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#include <config.h>
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/* Specification. */
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#include <stdlib.h>
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#include <errno.h>
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#if !_LIBC
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# define __set_errno(ev) ((errno) = (ev))
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#endif
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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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#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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#if _LIBC || !HAVE_UNSETENV
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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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#else /* HAVE_UNSETENV */
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# undef unsetenv
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# if !HAVE_DECL_UNSETENV
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# if VOID_UNSETENV
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extern void unsetenv (const char *);
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# else
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extern int unsetenv (const char *);
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# endif
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# endif
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/* Call the underlying unsetenv, in case there is hidden bookkeeping
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that needs updating beyond just modifying environ. */
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int
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rpl_unsetenv (const char *name)
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{
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int result = 0;
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if (!name || !*name || strchr (name, '='))
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{
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errno = EINVAL;
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return -1;
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}
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while (getenv (name))
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# if !VOID_UNSETENV
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result =
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# endif
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unsetenv (name);
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return result;
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}
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#endif /* HAVE_UNSETENV */
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