1 /* $OpenBSD: getenv.c,v 1.13 2024/07/10 14:17:58 jca 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
35 /*
36 * __findenv --
37 * Returns pointer to value associated with name, if any, else NULL.
38 * Starts searching within the environmental array at offset.
39 * Sets offset to be the offset of the name/value combination in the
40 * environmental array, for use by putenv(3), setenv(3) and unsetenv(3).
41 * Explicitly removes '=' in argument name.
42 */
43 char *
__findenv(const char * name,int len,int * offset)44 __findenv(const char *name, int len, int *offset)
45 {
46 int i;
47 const char *np;
48 char **p, *cp;
49
50 if (name == NULL || environ == NULL)
51 return (NULL);
52 for (p = environ + *offset; (cp = *p) != NULL; ++p) {
53 for (np = name, i = len; i && *cp; i--)
54 if (*cp++ != *np++)
55 break;
56 if (i == 0 && *cp++ == '=') {
57 *offset = p - environ;
58 return (cp);
59 }
60 }
61 return (NULL);
62 }
63
64 /*
65 * getenv --
66 * Returns ptr to value associated with name, if any, else NULL.
67 */
68 char *
getenv(const char * name)69 getenv(const char *name)
70 {
71 int offset = 0;
72 const char *np;
73
74 for (np = name; *np && *np != '='; ++np)
75 ;
76 return (__findenv(name, (int)(np - name), &offset));
77 }
78 DEF_STRONG(getenv);
79