xref: /titanic_41/usr/src/lib/libbc/libc/gen/common/getenv.c (revision ae115bc77f6fcde83175c75b4206dc2e50747966)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*      Copyright (c) 1984 AT&T */
23 /*        All Rights Reserved   */
24 
25 #pragma ident	"%Z%%M%	%I%	%E% SMI"  /* from S5R2 1.2 */
26 
27 /*LINTLIBRARY*/
28 /*
29  *	getenv(name)
30  *	returns ptr to value associated with name, if any, else NULL
31  */
32 #define NULL	0
33 extern char **environ;
34 static char *nvmatch();
35 
36 char *
37 getenv(name)
38 register char *name;
39 {
40 	register char *v, **p=environ;
41 
42 	if(p == NULL)
43 		return(NULL);
44 	while(*p != NULL)
45 		if((v = nvmatch(name, *p++)) != NULL)
46 			return(v);
47 	return(NULL);
48 }
49 
50 /*
51  *	s1 is either name, or name=value
52  *	s2 is name=value
53  *	if names match, return value of s2, else NULL
54  *	used for environment searching: see getenv
55  */
56 
57 static char *
58 nvmatch(s1, s2)
59 register char *s1, *s2;
60 {
61 	while(*s1 == *s2++)
62 		if(*s1++ == '=')
63 			return(s2);
64 	if(*s1 == '\0' && *(s2-1) == '=')
65 		return(s2);
66 	return(NULL);
67 }
68