xref: /titanic_44/usr/src/lib/libbc/libc/gen/common/getenv.c (revision 7c478bd95313f5f23a4c958a745db2134aa03244)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*      Copyright (c) 1984 AT&T */
/*        All Rights Reserved   */

#pragma ident	"%Z%%M%	%I%	%E% SMI"  /* from S5R2 1.2 */

/*LINTLIBRARY*/
/*
 *	getenv(name)
 *	returns ptr to value associated with name, if any, else NULL
 */
#define NULL	0
extern char **environ;
static char *nvmatch();

char *
getenv(name)
register char *name;
{
	register char *v, **p=environ;

	if(p == NULL)
		return(NULL);
	while(*p != NULL)
		if((v = nvmatch(name, *p++)) != NULL)
			return(v);
	return(NULL);
}

/*
 *	s1 is either name, or name=value
 *	s2 is name=value
 *	if names match, return value of s2, else NULL
 *	used for environment searching: see getenv
 */

static char *
nvmatch(s1, s2)
register char *s1, *s2;
{
	while(*s1 == *s2++)
		if(*s1++ == '=')
			return(s2);
	if(*s1 == '\0' && *(s2-1) == '=')
		return(s2);
	return(NULL);
}