1 /* $OpenBSD: getenv.c,v 1.10 2010/08/23 22:31:50 millert 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 len, int *offset);
35
36 /*
37 * __findenv --
38 * Returns pointer to value associated with name, if any, else NULL.
39 * Starts searching within the environmental array at offset.
40 * Sets offset to be the offset of the name/value combination in the
41 * environmental array, for use by putenv(3), setenv(3) and unsetenv(3).
42 * Explicitly removes '=' in argument name.
43 *
44 * This routine *should* be a static; don't use it.
45 */
46 char *
__findenv(const char * name,int len,int * offset)47 __findenv(const char *name, int len, int *offset)
48 {
49 extern char **environ;
50 int i;
51 const char *np;
52 char **p, *cp;
53
54 if (name == NULL || environ == NULL)
55 return (NULL);
56 for (p = environ + *offset; (cp = *p) != NULL; ++p) {
57 for (np = name, i = len; i && *cp; i--)
58 if (*cp++ != *np++)
59 break;
60 if (i == 0 && *cp++ == '=') {
61 *offset = p - environ;
62 return (cp);
63 }
64 }
65 return (NULL);
66 }
67
68 /*
69 * getenv --
70 * Returns ptr to value associated with name, if any, else NULL.
71 */
72 char *
getenv(const char * name)73 getenv(const char *name)
74 {
75 int offset = 0;
76 const char *np;
77
78 for (np = name; *np && *np != '='; ++np)
79 ;
80 return (__findenv(name, (int)(np - name), &offset));
81 }
82