xref: /freebsd/usr.bin/cmp/cmp.c (revision a79b71281cd63ad7a6cc43a6d5673a2510b51630)
1 /*
2  * Copyright (c) 1987, 1990, 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * $FreeBSD$
34  *
35  */
36 
37 #ifndef lint
38 static const char copyright[] =
39 "@(#) Copyright (c) 1987, 1990, 1993, 1994\n\
40 	The Regents of the University of California.  All rights reserved.\n";
41 #endif /* not lint */
42 
43 #ifndef lint
44 static const char sccsid[] = "@(#)cmp.c	8.3 (Berkeley) 4/2/94";
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 
57 #include "extern.h"
58 
59 int	lflag, sflag, xflag;
60 
61 static void usage __P((void));
62 
63 int
64 main(argc, argv)
65 	int argc;
66 	char *argv[];
67 {
68 	struct stat sb1, sb2;
69 	off_t skip1, skip2;
70 	int ch, fd1, fd2, special;
71 	char *file1, *file2;
72 
73 	while ((ch = getopt(argc, argv, "-lsx")) != -1)
74 		switch (ch) {
75 		case 'l':		/* print all differences */
76 			lflag = 1;
77 			break;
78 		case 's':		/* silent run */
79 			sflag = 1;
80 			break;
81 		case 'x':		/* hex output */
82 			lflag = 1;
83 			xflag = 1;
84 			break;
85 		case '-':		/* stdin (must be after options) */
86 			--optind;
87 			goto endargs;
88 		case '?':
89 		default:
90 			usage();
91 		}
92 endargs:
93 	argv += optind;
94 	argc -= optind;
95 
96 	if (lflag && sflag)
97 		errx(ERR_EXIT, "only one of -l and -s may be specified");
98 
99 	if (argc < 2 || argc > 4)
100 		usage();
101 
102 	/* Backward compatibility -- handle "-" meaning stdin. */
103 	special = 0;
104 	if (strcmp(file1 = argv[0], "-") == 0) {
105 		special = 1;
106 		fd1 = 0;
107 		file1 = "stdin";
108 	}
109 	else if ((fd1 = open(file1, O_RDONLY, 0)) < 0) {
110 		if (!sflag)
111 			err(ERR_EXIT, "%s", file1);
112 		else
113 			exit(1);
114 	}
115 	if (strcmp(file2 = argv[1], "-") == 0) {
116 		if (special)
117 			errx(ERR_EXIT,
118 				"standard input may only be specified once");
119 		special = 1;
120 		fd2 = 0;
121 		file2 = "stdin";
122 	}
123 	else if ((fd2 = open(file2, O_RDONLY, 0)) < 0) {
124 		if (!sflag)
125 			err(ERR_EXIT, "%s", file2);
126 		else
127 			exit(1);
128 	}
129 
130 	skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
131 	skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
132 
133 	if (!special) {
134 		if (fstat(fd1, &sb1)) {
135 			if (!sflag)
136 				err(ERR_EXIT, "%s", file1);
137 			else
138 				exit(1);
139 		}
140 		if (!S_ISREG(sb1.st_mode))
141 			special = 1;
142 		else {
143 			if (fstat(fd2, &sb2)) {
144 				if (!sflag)
145 					err(ERR_EXIT, "%s", file2);
146 				else
147 					exit(1);
148 			}
149 			if (!S_ISREG(sb2.st_mode))
150 				special = 1;
151 		}
152 	}
153 
154 	if (special)
155 		c_special(fd1, file1, skip1, fd2, file2, skip2);
156 	else
157 		c_regular(fd1, file1, skip1, sb1.st_size,
158 		    fd2, file2, skip2, sb2.st_size);
159 	exit(0);
160 }
161 
162 static void
163 usage()
164 {
165 
166 	(void)fprintf(stderr,
167 	    "usage: cmp [-l | -s] file1 file2 [skip1 [skip2]]\n");
168 	exit(ERR_EXIT);
169 }
170