/*      $NetBSD: getenv.c,v 1.37 2022/02/11 21:36:46 rillig 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[] = "@(#)getenv.c    8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: getenv.c,v 1.37 2022/02/11 21:36:46 rillig Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>

#include "env.h"
#include "local.h"

__weak_alias(getenv_r, _getenv_r)

/*
* getenv --
*      Returns ptr to value associated with name, if any, else NULL.
*      XXX: we cannot use getenv_r to implement this, because getenv()
*      cannot use a shared buffer, because if it did, subsequent calls
*      to getenv would trash previous results.
*/
char *
getenv(const char *name)
{
       size_t l_name;
       char *result;

       _DIAGASSERT(name != NULL);

       l_name = __envvarnamelen(name, false);
       if (l_name == 0)
               return NULL;

       result = NULL;
       if (__readlockenv()) {
               result = __findenvvar(name, l_name);
               (void)__unlockenv();
       }

       return result;
}

int
getenv_r(const char *name, char *buf, size_t len)
{
       size_t l_name;
       int rv;

       _DIAGASSERT(name != NULL);

       l_name = __envvarnamelen(name, false);
       if (l_name == 0) {
               errno = ENOENT;
               return -1;
       }

       rv = -1;
       if (__readlockenv()) {
               const char *value;

               value = __findenvvar(name, l_name);
               if (value != NULL) {
                       if (strlcpy(buf, value, len) < len) {
                               rv = 0;
                       } else {
                               errno = ERANGE;
                       }
               } else {
                       errno = ENOENT;
               }
               (void)__unlockenv();
       }

       return rv;
}