107 lines
3.2 KiB
C
107 lines
3.2 KiB
C
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/* $NetBSD: unsetenv.c,v 1.10 2010/11/14 18:11:43 tron Exp $ */
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/*
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* Copyright (c) 1987, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "from: @(#)setenv.c 8.1 (Berkeley) 6/4/93";
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#else
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__RCSID("$NetBSD: unsetenv.c,v 1.10 2010/11/14 18:11:43 tron Exp $");
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#endif
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#endif /* LIBC_SCCS and not lint */
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#include "namespace.h"
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#include <assert.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <bitstring.h>
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#include "env.h"
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#include "reentrant.h"
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#include "local.h"
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/*
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* unsetenv(name) --
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* Delete environmental variable "name".
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*/
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int
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unsetenv(const char *name)
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{
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size_t l_name;
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ssize_t r_offset, w_offset;
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_DIAGASSERT(name != NULL);
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l_name = __envvarnamelen(name, false);
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if (l_name == 0) {
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errno = EINVAL;
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return -1;
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}
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if (!__writelockenv())
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return -1;
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/* Search for the given name in the environment. */
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r_offset = __getenvslot(name, l_name, false);
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if (r_offset == -1) {
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/* Not found. */
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(void)__unlockenv();
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return 0;
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}
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__freeenvvar(environ[r_offset]);
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/*
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* Remove all matches from the environment and free the associated
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* memory if possible.
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*/
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w_offset = r_offset;
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while (environ[++r_offset] != NULL) {
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if (strncmp(environ[r_offset], name, l_name) != 0 ||
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environ[r_offset][l_name] != '=') {
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/* Not a match, keep this entry. */
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environ[w_offset++] = environ[r_offset];
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} else {
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/* We found another match. */
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__freeenvvar(environ[r_offset]);
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}
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}
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/* Clear out remaining stale entries in the environment vector. */
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do {
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environ[w_offset++] = NULL;
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} while (w_offset < r_offset);
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(void)__unlockenv();
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return 0;
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}
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