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      1 /*	$NetBSD: getenv.c,v 1.37 2022/02/11 21:36:46 rillig Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1987, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 #if 0
     35 static char sccsid[] = "@(#)getenv.c	8.1 (Berkeley) 6/4/93";
     36 #else
     37 __RCSID("$NetBSD: getenv.c,v 1.37 2022/02/11 21:36:46 rillig Exp $");
     38 #endif
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #include "namespace.h"
     42 #include <assert.h>
     43 #include <errno.h>
     44 #include <stdlib.h>
     45 #include <string.h>
     46 
     47 #include "env.h"
     48 #include "local.h"
     49 
     50 __weak_alias(getenv_r, _getenv_r)
     51 
     52 /*
     53  * getenv --
     54  *	Returns ptr to value associated with name, if any, else NULL.
     55  *	XXX: we cannot use getenv_r to implement this, because getenv()
     56  *	cannot use a shared buffer, because if it did, subsequent calls
     57  *	to getenv would trash previous results.
     58  */
     59 char *
     60 getenv(const char *name)
     61 {
     62 	size_t l_name;
     63 	char *result;
     64 
     65 	_DIAGASSERT(name != NULL);
     66 
     67 	l_name = __envvarnamelen(name, false);
     68 	if (l_name == 0)
     69 		return NULL;
     70 
     71 	result = NULL;
     72 	if (__readlockenv()) {
     73 		result = __findenvvar(name, l_name);
     74 		(void)__unlockenv();
     75 	}
     76 
     77 	return result;
     78 }
     79 
     80 int
     81 getenv_r(const char *name, char *buf, size_t len)
     82 {
     83 	size_t l_name;
     84 	int rv;
     85 
     86 	_DIAGASSERT(name != NULL);
     87 
     88 	l_name = __envvarnamelen(name, false);
     89 	if (l_name == 0) {
     90 		errno = ENOENT;
     91 		return -1;
     92 	}
     93 
     94 	rv = -1;
     95 	if (__readlockenv()) {
     96 		const char *value;
     97 
     98 		value = __findenvvar(name, l_name);
     99 		if (value != NULL) {
    100 			if (strlcpy(buf, value, len) < len) {
    101 				rv = 0;
    102 			} else {
    103 				errno = ERANGE;
    104 			}
    105 		} else {
    106 			errno = ENOENT;
    107 		}
    108 		(void)__unlockenv();
    109 	}
    110 
    111 	return rv;
    112 }
    113