xref: /openbsd-src/usr.bin/printenv/printenv.c (revision 0bd1216cbfac4316d823b5f086842b66ddea2018)
1 /*	$OpenBSD: printenv.c,v 1.8 2015/10/09 01:37:08 deraadt 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. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <stdio.h>
33 #include <string.h>
34 #include <stdlib.h>
35 #include <unistd.h>
36 #include <err.h>
37 
38 /*
39  * printenv
40  *
41  * Bill Joy, UCB
42  * February, 1979
43  */
44 int
main(int argc,char * argv[])45 main(int argc, char *argv[])
46 {
47 	extern char **environ;
48 	char *cp, **ep;
49 	int len;
50 
51 	if (pledge("stdio", NULL) == -1)
52 		err(1, "pledge");
53 
54 	if (argc < 2) {
55 		for (ep = environ; *ep; ep++)
56 			puts(*ep);
57 		exit(0);
58 	}
59 	len = strlen(*++argv);
60 	for (ep = environ; *ep; ep++)
61 		if (!strncmp(*ep, *argv, len)) {
62 			cp = *ep + len;
63 			if (!*cp || *cp == '=') {
64 				puts(*cp ? cp + 1 : cp);
65 				exit(0);
66 			}
67 		}
68 	exit(1);
69 }
70