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getenv.c revision 1.8 
      1 /*	$NetBSD: getenv.c,v 1.8 1997/07/13 20:16:41 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1987 Regents of the University of California.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char *sccsid = "from: @(#)getenv.c	5.8 (Berkeley) 2/23/91";
     40 #else
     41 __RCSID("$NetBSD: getenv.c,v 1.8 1997/07/13 20:16:41 christos Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include <stdlib.h>
     46 #include <string.h>
     47 #include "local.h"
     48 
     49 /*
     50  * getenv --
     51  *	Returns ptr to value associated with name, if any, else NULL.
     52  */
     53 char *
     54 getenv(name)
     55 	const char *name;
     56 {
     57 	int offset;
     58 
     59 	return(__findenv(name, &offset));
     60 }
     61 
     62 /*
     63  * __findenv --
     64  *	Returns pointer to value associated with name, if any, else NULL.
     65  *	Sets offset to be the offset of the name/value combination in the
     66  *	environmental array, for use by setenv(3) and unsetenv(3).
     67  *	Explicitly removes '=' in argument name.
     68  *
     69  *	This routine *should* be a static; don't use it.
     70  */
     71 char *
     72 __findenv(name, offset)
     73 	register const char *name;
     74 	int *offset;
     75 {
     76 	extern char **environ;
     77 	register int len;
     78 	register char **P, *C;
     79 	register const char *tmp;
     80 
     81 	for (tmp = name, len = 0; *tmp && *tmp != '='; ++tmp, ++len);
     82 	for (P = environ; *P; ++P)
     83 		if (!strncmp(*P, name, len))
     84 			if (*(C = *P + len) == '=') {
     85 				*offset = P - environ;
     86 				return(++C);
     87 			}
     88 	return(NULL);
     89 }
     90