/*      $NetBSD: printenv.c,v 1.12 2011/09/06 18:26:55 joerg Exp $      */

/*
* Copyright (c) 1987, 1993
*    The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1987, 1993\
The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
/*static char sccsid[] = "from: @(#)printenv.c  8.2 (Berkeley) 5/4/95";*/
__RCSID("$NetBSD: printenv.c,v 1.12 2011/09/06 18:26:55 joerg Exp $");
#endif /* not lint */

#include <sys/types.h>

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <err.h>

__dead static void usage(void);

/*
* printenv
*
* Bill Joy, UCB
* February, 1979
*/
int
main(int argc, char *argv[])
{
       extern char **environ;
       char *cp, **ep;
       size_t len;
       int ch;

       while ((ch = getopt(argc, argv, "")) != -1)
               switch(ch) {
               case '?':
               default:
                       usage();
               }
       argc -= optind;
       argv += optind;

       if (argc == 0) {
               for (ep = environ; *ep; ep++)
                       (void)printf("%s\n", *ep);
               exit(0);
       }
       if (argc != 1)
               usage();
       if (strchr(*argv, '=') != NULL)
               errx(1, "Invalid environment variable %s", *argv);
       len = strlen(*argv);
       for (ep = environ; *ep; ep++)
               if (!memcmp(*ep, *argv, len)) {
                       cp = *ep + len;
                       if (!*cp || *cp == '=') {
                               (void)printf("%s\n", *cp ? cp + 1 : cp);
                               exit(0);
                       }
               }
       exit(1);
}

static void
usage(void)
{
       (void)fprintf(stderr, "Usage: printenv [name]\n");
       exit(1);
}