xref: /openbsd-src/usr.bin/cmp/cmp.c (revision 898184e3e61f9129feb5978fad5a8c6865f00b92)
1 /*      $OpenBSD: cmp.c,v 1.12 2009/10/27 23:59:36 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 #include <sys/types.h>
34 #include <sys/stat.h>
35 
36 #include <err.h>
37 #include <fcntl.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42 #include <locale.h>
43 
44 #include "extern.h"
45 
46 int	lflag, sflag;
47 
48 static void usage(void);
49 
50 int
51 main(int argc, char *argv[])
52 {
53 	struct stat sb1, sb2;
54 	off_t skip1, skip2;
55 	int ch, fd1, fd2, special;
56 	char *file1, *file2;
57 
58 	setlocale(LC_ALL, "");
59 
60 	while ((ch = getopt(argc, argv, "ls")) != -1)
61 		switch (ch) {
62 		case 'l':		/* print all differences */
63 			lflag = 1;
64 			break;
65 		case 's':		/* silent run */
66 			sflag = 1;
67 			break;
68 		case '?':
69 		default:
70 			usage();
71 		}
72 
73 	argv += optind;
74 	argc -= optind;
75 
76 	if (lflag && sflag)
77 		errx(ERR_EXIT, "only one of -l and -s may be specified");
78 
79 	if (argc < 2 || argc > 4)
80 		usage();
81 
82 	/* Backward compatibility -- handle "-" meaning stdin. */
83 	special = 0;
84 	if (strcmp(file1 = argv[0], "-") == 0) {
85 		special = 1;
86 		fd1 = 0;
87 		file1 = "stdin";
88 	} else if ((fd1 = open(file1, O_RDONLY, 0)) < 0) {
89 		if (sflag)
90 			exit(ERR_EXIT);
91 		else
92 			err(ERR_EXIT, "%s", file1);
93 	}
94 	if (strcmp(file2 = argv[1], "-") == 0) {
95 		if (special) {
96 			if (sflag)
97 				exit(ERR_EXIT);
98 			else
99 				errx(ERR_EXIT,
100 					"standard input may only be specified once");
101 		}
102 		special = 1;
103 		fd2 = 0;
104 		file2 = "stdin";
105 	} else if ((fd2 = open(file2, O_RDONLY, 0)) < 0) {
106 		if (sflag)
107 			exit(ERR_EXIT);
108 		else
109 			err(ERR_EXIT, "%s", file2);
110 	}
111 
112 	skip1 = argc > 2 ? strtoq(argv[2], NULL, 0) : 0;
113 	skip2 = argc == 4 ? strtoq(argv[3], NULL, 0) : 0;
114 
115 	if (!special) {
116 		if (fstat(fd1, &sb1)) {
117 			if (sflag)
118 				exit(ERR_EXIT);
119 			else
120 				err(ERR_EXIT, "%s", file1);
121 		}
122 		if (!S_ISREG(sb1.st_mode))
123 			special = 1;
124 		else {
125 			if (fstat(fd2, &sb2)) {
126 				if (sflag)
127 					exit(ERR_EXIT);
128 				else
129 					err(ERR_EXIT, "%s", file2);
130 			}
131 			if (!S_ISREG(sb2.st_mode))
132 				special = 1;
133 		}
134 	}
135 
136 	if (special)
137 		c_special(fd1, file1, skip1, fd2, file2, skip2);
138 	else
139 		c_regular(fd1, file1, skip1, sb1.st_size,
140 		    fd2, file2, skip2, sb2.st_size);
141 	return 0;
142 }
143 
144 static void
145 usage(void)
146 {
147 
148 	(void)fprintf(stderr,
149 	    "usage: cmp [-l | -s] file1 file2 [skip1 [skip2]]\n");
150 	exit(ERR_EXIT);
151 }
152