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      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