xref: /freebsd/usr.bin/printenv/printenv.c (revision e796cc77c586c2955b2f3940dbf4991b31e8d289)
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 __FBSDID("$FreeBSD$");
46 
47 #include <sys/types.h>
48 
49 #include <capsicum_helpers.h>
50 #include <err.h>
51 #include <stdlib.h>
52 #include <stdio.h>
53 #include <string.h>
54 #include <unistd.h>
55 
56 void	usage(void);
57 extern char **environ;
58 
59 /*
60  * printenv
61  *
62  * Bill Joy, UCB
63  * February, 1979
64  */
65 int
66 main(int argc, char *argv[])
67 {
68 	char *cp, **ep;
69 	size_t len;
70 	int ch;
71 
72 	if (caph_limit_stdio() < 0 || (cap_enter() < 0 && errno != ENOSYS))
73 		err(1, "capsicum");
74 
75 	while ((ch = getopt(argc, argv, "")) != -1)
76 		switch(ch) {
77 		case '?':
78 		default:
79 			usage();
80 		}
81 	argc -= optind;
82 	argv += optind;
83 
84 	if (argc == 0) {
85 		for (ep = environ; *ep; ep++)
86 			(void)printf("%s\n", *ep);
87 		exit(0);
88 	}
89 	len = strlen(*argv);
90 	for (ep = environ; *ep; ep++)
91 		if (!memcmp(*ep, *argv, len)) {
92 			cp = *ep + len;
93 			if (*cp == '=') {
94 				(void)printf("%s\n", cp + 1);
95 				exit(0);
96 			}
97 		}
98 	exit(1);
99 }
100 
101 void
102 usage(void)
103 {
104 	(void)fprintf(stderr, "usage: printenv [name]\n");
105 	exit(1);
106 }
107