xref: /netbsd/lib/libc/stdlib/putenv.c (revision 6550d01e)
1 /*	$NetBSD: putenv.c,v 1.19 2010/11/14 18:11:43 tron Exp $	*/
2 
3 /*-
4  * Copyright (c) 1988, 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[] = "@(#)putenv.c	8.2 (Berkeley) 3/27/94";
36 #else
37 __RCSID("$NetBSD: putenv.c,v 1.19 2010/11/14 18:11:43 tron Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40 
41 #include "namespace.h"
42 
43 #include <assert.h>
44 #include <errno.h>
45 #include <stdlib.h>
46 #include <string.h>
47 
48 #include "env.h"
49 #include "reentrant.h"
50 #include "local.h"
51 
52 #ifdef __weak_alias
53 __weak_alias(putenv,_putenv)
54 #endif
55 
56 int
57 putenv(char *str)
58 {
59 	size_t l_name;
60 	int rv;
61 
62 	_DIAGASSERT(str != NULL);
63 
64 	l_name = __envvarnamelen(str, true);
65 	if (l_name == 0) {
66 		errno = EINVAL;
67 		return -1;
68 	}
69 
70 	rv = -1;
71 	if (__writelockenv()) {
72 		ssize_t offset;
73 
74 		offset = __getenvslot(str, l_name, true);
75 		if (offset != -1) {
76 			if (environ[offset] != NULL)
77 				__freeenvvar(environ[offset]);
78 			environ[offset] = str;
79 
80 			rv = 0;
81 		}
82 
83 		(void)__unlockenv();
84 	}
85 
86 	return rv;
87 }
88