xref: /openbsd-src/usr.bin/cmp/cmp.c (revision a28daedfc357b214be5c701aa8ba8adb29a7f1c2)
1 /*      $OpenBSD: cmp.c,v 1.11 2003/06/10 22:20:45 deraadt Exp $      */
2 /*      $NetBSD: cmp.c,v 1.7 1995/09/08 03:22:56 tls Exp $      */
3 
4 /*
5  * Copyright (c) 1987, 1990, 1993, 1994
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 #ifndef lint
34 static char copyright[] =
35 "@(#) Copyright (c) 1987, 1990, 1993, 1994\n\
36 	The Regents of the University of California.  All rights reserved.\n";
37 #endif /* not lint */
38 
39 #ifndef lint
40 #if 0
41 static char sccsid[] = "@(#)cmp.c	8.3 (Berkeley) 4/2/94";
42 #else
43 static char rcsid[] = "$OpenBSD: cmp.c,v 1.11 2003/06/10 22:20:45 deraadt Exp $";
44 #endif
45 #endif /* not lint */
46 
47 #include <sys/types.h>
48 #include <sys/stat.h>
49 
50 #include <err.h>
51 #include <fcntl.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <unistd.h>
56 #include <locale.h>
57 
58 #include "extern.h"
59 
60 int	lflag, sflag;
61 
62 static void usage(void);
63 
64 int
65 main(int argc, char *argv[])
66 {
67 	struct stat sb1, sb2;
68 	off_t skip1, skip2;
69 	int ch, fd1, fd2, special;
70 	char *file1, *file2;
71 
72 	setlocale(LC_ALL, "");
73 
74 	while ((ch = getopt(argc, argv, "ls")) != -1)
75 		switch (ch) {
76 		case 'l':		/* print all differences */
77 			lflag = 1;
78 			break;
79 		case 's':		/* silent run */
80 			sflag = 1;
81 			break;
82 		case '?':
83 		default:
84 			usage();
85 		}
86 
87 	argv += optind;
88 	argc -= optind;
89 
90 	if (lflag && sflag)
91 		errx(ERR_EXIT, "only one of -l and -s may be specified");
92 
93 	if (argc < 2 || argc > 4)
94 		usage();
95 
96 	/* Backward compatibility -- handle "-" meaning stdin. */
97 	special = 0;
98 	if (strcmp(file1 = argv[0], "-") == 0) {
99 		special = 1;
100 		fd1 = 0;
101 		file1 = "stdin";
102 	} else if ((fd1 = open(file1, O_RDONLY, 0)) < 0) {
103 		if (sflag)
104 			exit(ERR_EXIT);
105 		else
106 			err(ERR_EXIT, "%s", file1);
107 	}
108 	if (strcmp(file2 = argv[1], "-") == 0) {
109 		if (special) {
110 			if (sflag)
111 				exit(ERR_EXIT);
112 			else
113 				errx(ERR_EXIT,
114 					"standard input may only be specified once");
115 		}
116 		special = 1;
117 		fd2 = 0;
118 		file2 = "stdin";
119 	} else if ((fd2 = open(file2, O_RDONLY, 0)) < 0) {
120 		if (sflag)
121 			exit(ERR_EXIT);
122 		else
123 			err(ERR_EXIT, "%s", file2);
124 	}
125 
126 	skip1 = argc > 2 ? strtoq(argv[2], NULL, 0) : 0;
127 	skip2 = argc == 4 ? strtoq(argv[3], NULL, 0) : 0;
128 
129 	if (!special) {
130 		if (fstat(fd1, &sb1)) {
131 			if (sflag)
132 				exit(ERR_EXIT);
133 			else
134 				err(ERR_EXIT, "%s", file1);
135 		}
136 		if (!S_ISREG(sb1.st_mode))
137 			special = 1;
138 		else {
139 			if (fstat(fd2, &sb2)) {
140 				if (sflag)
141 					exit(ERR_EXIT);
142 				else
143 					err(ERR_EXIT, "%s", file2);
144 			}
145 			if (!S_ISREG(sb2.st_mode))
146 				special = 1;
147 		}
148 	}
149 
150 	if (special)
151 		c_special(fd1, file1, skip1, fd2, file2, skip2);
152 	else
153 		c_regular(fd1, file1, skip1, sb1.st_size,
154 		    fd2, file2, skip2, sb2.st_size);
155 	return 0;
156 }
157 
158 static void
159 usage(void)
160 {
161 
162 	(void)fprintf(stderr,
163 	    "usage: cmp [-l | -s] file1 file2 [skip1 [skip2]]\n");
164 	exit(ERR_EXIT);
165 }
166