1 /* $NetBSD: setenv.c,v 1.44 2015/01/20 18:31:25 christos 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[] = "@(#)setenv.c 8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: setenv.c,v 1.44 2015/01/20 18:31:25 christos 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 "local.h"
50
51 #ifdef __weak_alias
__weak_alias(setenv,_setenv)52 __weak_alias(setenv,_setenv)
53 #endif
54
55 /*
56 * setenv --
57 * Set the value of the environmental variable "name" to be
58 * "value". If rewrite is set, replace any current value.
59 */
60 int
61 setenv(const char *name, const char *value, int rewrite)
62 {
63 size_t l_name, l_value, length;
64 ssize_t offset;
65 char *envvar;
66
67 _DIAGASSERT(name != NULL);
68 _DIAGASSERT(value != NULL);
69
70 l_name = __envvarnamelen(name, false);
71 if (l_name == 0 || value == NULL) {
72 errno = EINVAL;
73 return -1;
74 }
75
76 if (!__writelockenv())
77 return -1;
78
79 /* Find slot in the enviroment. */
80 offset = __getenvslot(name, l_name, true);
81 if (offset == -1)
82 goto bad;
83
84 l_value = strlen(value);
85 length = l_name + l_value + 2;
86
87 /* Handle overwriting a current environt variable. */
88 envvar = environ[offset];
89 if (envvar != NULL) {
90 if (!rewrite)
91 goto good;
92 /*
93 * Check whether the buffer was allocated via setenv(3) and
94 * whether there is enough space. If so simply overwrite the
95 * existing value.
96 */
97 if (__canoverwriteenvvar(envvar, length)) {
98 envvar += l_name + 1;
99 goto copy;
100 }
101 }
102
103 /* Allocate memory for name + `=' + value + NUL. */
104 if ((envvar = __allocenvvar(length)) == NULL)
105 goto bad;
106
107 if (environ[offset] != NULL)
108 __freeenvvar(environ[offset]);
109
110 environ[offset] = envvar;
111
112 (void)memcpy(envvar, name, l_name);
113
114 envvar += l_name;
115 *envvar++ = '=';
116
117 copy:
118 (void)memcpy(envvar, value, l_value + 1);
119
120 good:
121 (void)__unlockenv();
122 return 0;
123
124 bad:
125 (void)__unlockenv();
126 return -1;
127 }
128