xref: /netbsd-src/lib/libc/compat/stdlib/compat_unsetenv.c (revision da39824b722dbd84beb9a1ab7e8de6710cc44d4b)
1 /*	$NetBSD: compat_unsetenv.c,v 1.3 2010/11/14 18:11:42 tron 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[] = "from: @(#)setenv.c	8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: compat_unsetenv.c,v 1.3 2010/11/14 18:11:42 tron Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40 
41 #define __LIBC12_SOURCE__
42 #include "namespace.h"
43 
44 #include <assert.h>
45 #include <errno.h>
46 #include <stdlib.h>
47 #include <compat/include/stdlib.h>
48 #include <string.h>
49 #include <bitstring.h>
50 #include "reentrant.h"
51 #include "local.h"
52 
53 #ifdef __weak_alias
54 __weak_alias(unsetenv,_unsetenv)
55 #endif
56 
57 #include "env.h"
58 
59 __warn_references(unsetenv,
60     "warning: reference to compatibility unsetenv();"
61     " include <stdlib.h> for correct reference")
62 
63 /*
64  * unsetenv(name) --
65  *	Delete environmental variable "name".
66  */
67 void
68 unsetenv(const char *name)
69 {
70 	size_t l_name;
71 
72 	_DIAGASSERT(name != NULL);
73 
74 	l_name = strlen(name);
75 	if (__writelockenv()) {
76 		ssize_t offset;
77 
78 		while ((offset = __getenvslot(name, l_name, false)) != -1) {
79 			char **p;
80 			for (p = &environ[offset]; ; ++p) {
81 				if ((*p = *(p + 1)) == NULL)
82 					break;
83 			}
84 		}
85 		(void)__unlockenv();
86 	}
87 }
88