1 /* $OpenBSD: getenv.c,v 1.8 2005/08/08 08:05:36 espie Exp $ */
2 /*
3 * Copyright (c) 1987, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <stdlib.h>
32 #include <string.h>
33
34 char *__findenv(const char *name, int *offset);
35
36 /*
37 * __findenv --
38 * Returns pointer to value associated with name, if any, else NULL.
39 * Sets offset to be the offset of the name/value combination in the
40 * environmental array, for use by setenv(3) and unsetenv(3).
41 * Explicitly removes '=' in argument name.
42 *
43 * This routine *should* be a static; don't use it.
44 */
45 char *
__findenv(const char * name,int * offset)46 __findenv(const char *name, int *offset)
47 {
48 extern char **environ;
49 int len, i;
50 const char *np;
51 char **p, *cp;
52
53 if (name == NULL || environ == NULL)
54 return (NULL);
55 for (np = name; *np && *np != '='; ++np)
56 ;
57 len = np - name;
58 for (p = environ; (cp = *p) != NULL; ++p) {
59 for (np = name, i = len; i && *cp; i--)
60 if (*cp++ != *np++)
61 break;
62 if (i == 0 && *cp++ == '=') {
63 *offset = p - environ;
64 return (cp);
65 }
66 }
67 return (NULL);
68 }
69
70 /*
71 * getenv --
72 * Returns ptr to value associated with name, if any, else NULL.
73 */
74 char *
getenv(const char * name)75 getenv(const char *name)
76 {
77 int offset;
78
79 return (__findenv(name, &offset));
80 }
81