xref: /freebsd/usr.bin/cmp/cmp.c (revision 0b87f79976047c8f4332bbf7dc03146f6b0de79f)
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 
34 #ifndef lint
35 static const char copyright[] =
36 "@(#) Copyright (c) 1987, 1990, 1993, 1994\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif
39 
40 #if 0
41 #ifndef lint
42 static char sccsid[] = "@(#)cmp.c	8.3 (Berkeley) 4/2/94";
43 #endif
44 #endif
45 
46 #include <sys/cdefs.h>
47 __FBSDID("$FreeBSD$");
48 
49 #include <sys/types.h>
50 #include <sys/stat.h>
51 
52 #include <err.h>
53 #include <fcntl.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58 
59 #include "extern.h"
60 
61 int	lflag, sflag, xflag, zflag;
62 
63 static void usage(void);
64 
65 int
66 main(argc, argv)
67 	int argc;
68 	char *argv[];
69 {
70 	struct stat sb1, sb2;
71 	off_t skip1, skip2;
72 	int ch, fd1, fd2, special;
73 	const char *file1, *file2;
74 
75 	while ((ch = getopt(argc, argv, "lsxz")) != -1)
76 		switch (ch) {
77 		case 'l':		/* print all differences */
78 			lflag = 1;
79 			break;
80 		case 's':		/* silent run */
81 			sflag = 1;
82 			zflag = 1;
83 			break;
84 		case 'x':		/* hex output */
85 			lflag = 1;
86 			xflag = 1;
87 			break;
88 		case 'z':		/* compare size first */
89 			zflag = 1;
90 			break;
91 		case '?':
92 		default:
93 			usage();
94 		}
95 	argv += optind;
96 	argc -= optind;
97 
98 	if (lflag && sflag)
99 		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
100 
101 	if (argc < 2 || argc > 4)
102 		usage();
103 
104 	/* Backward compatibility -- handle "-" meaning stdin. */
105 	special = 0;
106 	if (strcmp(file1 = argv[0], "-") == 0) {
107 		special = 1;
108 		fd1 = 0;
109 		file1 = "stdin";
110 	}
111 	else if ((fd1 = open(file1, O_RDONLY, 0)) < 0) {
112 		if (!sflag)
113 			err(ERR_EXIT, "%s", file1);
114 		else
115 			exit(ERR_EXIT);
116 	}
117 	if (strcmp(file2 = argv[1], "-") == 0) {
118 		if (special)
119 			errx(ERR_EXIT,
120 				"standard input may only be specified once");
121 		special = 1;
122 		fd2 = 0;
123 		file2 = "stdin";
124 	}
125 	else if ((fd2 = open(file2, O_RDONLY, 0)) < 0) {
126 		if (!sflag)
127 			err(ERR_EXIT, "%s", file2);
128 		else
129 			exit(ERR_EXIT);
130 	}
131 
132 	skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
133 	skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
134 
135 	if (!special) {
136 		if (fstat(fd1, &sb1)) {
137 			if (!sflag)
138 				err(ERR_EXIT, "%s", file1);
139 			else
140 				exit(ERR_EXIT);
141 		}
142 		if (!S_ISREG(sb1.st_mode))
143 			special = 1;
144 		else {
145 			if (fstat(fd2, &sb2)) {
146 				if (!sflag)
147 					err(ERR_EXIT, "%s", file2);
148 				else
149 					exit(ERR_EXIT);
150 			}
151 			if (!S_ISREG(sb2.st_mode))
152 				special = 1;
153 		}
154 	}
155 
156 	if (special)
157 		c_special(fd1, file1, skip1, fd2, file2, skip2);
158 	else {
159 		if (zflag && sb1.st_size != sb2.st_size) {
160 			if (!sflag)
161 				(void) printf("%s %s differ: size\n",
162 				    file1, file2);
163 			exit(DIFF_EXIT);
164 		}
165 		c_regular(fd1, file1, skip1, sb1.st_size,
166 		    fd2, file2, skip2, sb2.st_size);
167 	}
168 	exit(0);
169 }
170 
171 static void
172 usage()
173 {
174 
175 	(void)fprintf(stderr,
176 	    "usage: cmp [-l | -s | -x] [-z] file1 file2 [skip1 [skip2]]\n");
177 	exit(ERR_EXIT);
178 }
179