xref: /openbsd-src/usr.bin/rev/rev.c (revision ac9b4aacc1da35008afea06a5d23c2f2dea9b93e)
1 /*	$OpenBSD: rev.c,v 1.10 2009/10/27 23:59:42 deraadt Exp $	*/
2 /*	$NetBSD: rev.c,v 1.5 1995/09/28 08:49:40 tls Exp $	*/
3 
4 /*-
5  * Copyright (c) 1987, 1992, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #include <sys/types.h>
34 
35 #include <err.h>
36 #include <errno.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <unistd.h>
41 
42 void usage(void);
43 
44 int
45 main(int argc, char *argv[])
46 {
47 	char *filename, *p, *t;
48 	FILE *fp;
49 	size_t len;
50 	int ch, rval;
51 
52 	while ((ch = getopt(argc, argv, "")) != -1)
53 		switch(ch) {
54 		case '?':
55 		default:
56 			usage();
57 		}
58 
59 	argc -= optind;
60 	argv += optind;
61 
62 	fp = stdin;
63 	filename = "stdin";
64 	rval = 0;
65 	do {
66 		if (*argv) {
67 			if ((fp = fopen(*argv, "r")) == NULL) {
68 				warn("%s", *argv);
69 				rval = 1;
70 				++argv;
71 				continue;
72 			}
73 			filename = *argv++;
74 		}
75 		while ((p = fgetln(fp, &len)) != NULL) {
76 			if (p[len - 1] == '\n')
77 				--len;
78 			for (t = p + len - 1; t >= p; --t)
79 				putchar(*t);
80 			putchar('\n');
81 		}
82 		if (ferror(fp)) {
83 			warn("%s", filename);
84 			rval = 1;
85 		}
86 		(void)fclose(fp);
87 	} while(*argv);
88 	exit(rval);
89 }
90 
91 void
92 usage(void)
93 {
94 	extern char *__progname;
95 
96 	(void)fprintf(stderr, "usage: %s [file ...]\n", __progname);
97 	exit(1);
98 }
99