xref: /freebsd/usr.bin/printenv/printenv.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1987, 1993
5  *	The Regents of the University of California.  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 #ifndef lint
33 static const char copyright[] =
34 "@(#) Copyright (c) 1987, 1993\n\
35 	The Regents of the University of California.  All rights reserved.\n";
36 #endif /* not lint */
37 
38 #if 0
39 #ifndef lint
40 static char sccsid[] = "@(#)printenv.c	8.2 (Berkeley) 5/4/95";
41 #endif /* not lint */
42 #endif
43 
44 #include <sys/cdefs.h>
45 #include <sys/types.h>
46 
47 #include <capsicum_helpers.h>
48 #include <err.h>
49 #include <stdlib.h>
50 #include <stdio.h>
51 #include <string.h>
52 #include <unistd.h>
53 
54 void	usage(void);
55 extern char **environ;
56 
57 /*
58  * printenv
59  *
60  * Bill Joy, UCB
61  * February, 1979
62  */
63 int
64 main(int argc, char *argv[])
65 {
66 	char *cp, **ep;
67 	size_t len;
68 	int ch;
69 
70 	if (caph_limit_stdio() < 0 || caph_enter() < 0)
71 		err(1, "capsicum");
72 
73 	while ((ch = getopt(argc, argv, "")) != -1)
74 		switch(ch) {
75 		case '?':
76 		default:
77 			usage();
78 		}
79 	argc -= optind;
80 	argv += optind;
81 
82 	if (argc == 0) {
83 		for (ep = environ; *ep; ep++)
84 			(void)printf("%s\n", *ep);
85 		exit(0);
86 	}
87 	len = strlen(*argv);
88 	for (ep = environ; *ep; ep++)
89 		if (!memcmp(*ep, *argv, len)) {
90 			cp = *ep + len;
91 			if (*cp == '=') {
92 				(void)printf("%s\n", cp + 1);
93 				exit(0);
94 			}
95 		}
96 	exit(1);
97 }
98 
99 void
100 usage(void)
101 {
102 	(void)fprintf(stderr, "usage: printenv [name]\n");
103 	exit(1);
104 }
105