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getenv.c revision 1.7 
      1 /*	$NetBSD: getenv.c,v 1.7 1996/12/20 20:32:54 cgd 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 #if defined(LIBC_SCCS) && !defined(lint)
     37 #if 0
     38 static char *sccsid = "from: @(#)getenv.c	5.8 (Berkeley) 2/23/91";
     39 #else
     40 static char *rcsid = "$NetBSD: getenv.c,v 1.7 1996/12/20 20:32:54 cgd Exp $";
     41 #endif
     42 #endif /* LIBC_SCCS and not lint */
     43 
     44 #include <stdlib.h>
     45 #include <string.h>
     46 
     47 /*
     48  * getenv --
     49  *	Returns ptr to value associated with name, if any, else NULL.
     50  */
     51 char *
     52 getenv(name)
     53 	const char *name;
     54 {
     55 	int offset;
     56 	char *__findenv();
     57 
     58 	return(__findenv(name, &offset));
     59 }
     60 
     61 /*
     62  * __findenv --
     63  *	Returns pointer to value associated with name, if any, else NULL.
     64  *	Sets offset to be the offset of the name/value combination in the
     65  *	environmental array, for use by setenv(3) and unsetenv(3).
     66  *	Explicitly removes '=' in argument name.
     67  *
     68  *	This routine *should* be a static; don't use it.
     69  */
     70 char *
     71 __findenv(name, offset)
     72 	register const char *name;
     73 	int *offset;
     74 {
     75 	extern char **environ;
     76 	register int len;
     77 	register char **P, *C;
     78 	register const char *tmp;
     79 
     80 	for (tmp = name, len = 0; *tmp && *tmp != '='; ++tmp, ++len);
     81 	for (P = environ; *P; ++P)
     82 		if (!strncmp(*P, name, len))
     83 			if (*(C = *P + len) == '=') {
     84 				*offset = P - environ;
     85 				return(++C);
     86 			}
     87 	return(NULL);
     88 }
     89