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Revision 1.3, Sun Nov 14 18:11:42 2010 UTC (13 years, 4 months ago) by tron
Branch: MAIN
CVS Tags: yamt-pagecache-tag8, yamt-pagecache-base9, yamt-pagecache-base8, yamt-pagecache-base7, yamt-pagecache-base6, yamt-pagecache-base5, yamt-pagecache-base4, yamt-pagecache-base3, yamt-pagecache-base2, yamt-pagecache-base, yamt-pagecache, tls-maxphys-base, tls-maxphys, tls-earlyentropy-base, tls-earlyentropy, riastradh-xf86-video-intel-2-7-1-pre-2-21-15, riastradh-drm2-base3, riastradh-drm2-base2, riastradh-drm2-base1, riastradh-drm2-base, riastradh-drm2, netbsd-7-nhusb-base-20170116, netbsd-7-nhusb-base, netbsd-7-nhusb, netbsd-7-base, netbsd-7-2-RELEASE, netbsd-7-1-RELEASE, netbsd-7-1-RC2, netbsd-7-1-RC1, netbsd-7-1-2-RELEASE, netbsd-7-1-1-RELEASE, netbsd-7-1, netbsd-7-0-RELEASE, netbsd-7-0-RC3, netbsd-7-0-RC2, netbsd-7-0-RC1, netbsd-7-0-2-RELEASE, netbsd-7-0-1-RELEASE, netbsd-7-0, netbsd-7, netbsd-6-base, netbsd-6-1-RELEASE, netbsd-6-1-RC4, netbsd-6-1-RC3, netbsd-6-1-RC2, netbsd-6-1-RC1, netbsd-6-1-5-RELEASE, netbsd-6-1-4-RELEASE, netbsd-6-1-3-RELEASE, netbsd-6-1-2-RELEASE, netbsd-6-1-1-RELEASE, netbsd-6-1, netbsd-6-0-RELEASE, netbsd-6-0-RC2, netbsd-6-0-RC1, netbsd-6-0-6-RELEASE, netbsd-6-0-5-RELEASE, netbsd-6-0-4-RELEASE, netbsd-6-0-3-RELEASE, netbsd-6-0-2-RELEASE, netbsd-6-0-1-RELEASE, netbsd-6-0, netbsd-6, matt-nb6-plus-nbase, matt-nb6-plus-base, matt-nb6-plus, matt-mips64-premerge-20101231, cherry-xenmp-base, cherry-xenmp, bouyer-quota2-nbase, bouyer-quota2-base, bouyer-quota2, agc-symver-base, agc-symver
Changes since 1.2: +17 -15 lines

Improve and simplify implementation of *env(3) functions:
- Use RB tree to keep track of memory allocated via setenv(3) as
  suggested by Enami Tsugutomo in private e-mail.
  This simplifies the code a lot as we no longer need to keep the size
  of "environ" in sync with an array of allocated environment variables.
  It also makes it possible to free environment variables in unsetenv(3)
  if something has changed the order of the "environ" array.
- Fix a bug in getenv(3) and getenv_r(3) which would return bogus
  results e.g. for " getenv("A=B") " if an environment variable "A"
  with value "B=C" exists.
- Clean up the internal functions:
  - Don't expose the read/write lock for the environment to other parts
    of "libc". Provide locking functions instead.
  - Use "bool" to report success or failure.
  - Use "ssize_t" or "size_t" instead of "int" for indexes.
  - Provide internal functions with simpler interfaces e.g. don't
    combine return values and reference arguments.
  - Don't copy "environ" into an allocated block unless we really need
    to grow it.

Code reviewed by Joerg Sonnenberger and Christos Zoulas, tested by
Joerg Sonnenberger and me. These changes also fix problems in
zsh 4.3.* and pam_ssh according to Joerg.

/*	$NetBSD: compat_unsetenv.c,v 1.3 2010/11/14 18:11:42 tron Exp $	*/

/*
 * Copyright (c) 1987, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "from: @(#)setenv.c	8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: compat_unsetenv.c,v 1.3 2010/11/14 18:11:42 tron Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#define __LIBC12_SOURCE__
#include "namespace.h"

#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <compat/include/stdlib.h>
#include <string.h>
#include <bitstring.h>
#include "reentrant.h"
#include "local.h"

#ifdef __weak_alias
__weak_alias(unsetenv,_unsetenv)
#endif

#include "env.h"

__warn_references(unsetenv,
    "warning: reference to compatibility unsetenv();"
    " include <stdlib.h> for correct reference")

/*
 * unsetenv(name) --
 *	Delete environmental variable "name".
 */
void
unsetenv(const char *name)
{
	size_t l_name;

	_DIAGASSERT(name != NULL);

	l_name = strlen(name);
	if (__writelockenv()) {
		ssize_t offset;

		while ((offset = __getenvslot(name, l_name, false)) != -1) {
			char **p;		
			for (p = &environ[offset]; ; ++p) {
				if ((*p = *(p + 1)) == NULL)
					break;
			}
		}
		(void)__unlockenv();
	}
}