xref: /freebsd/usr.bin/cmp/cmp.c (revision f1bb2cd2aa7488657658fbc09aae2ead579049ab)
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 '-':		/* stdin (must be after options) */
92 			--optind;
93 			goto endargs;
94 		case '?':
95 		default:
96 			usage();
97 		}
98 endargs:
99 	argv += optind;
100 	argc -= optind;
101 
102 	if (lflag && sflag)
103 		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
104 
105 	if (argc < 2 || argc > 4)
106 		usage();
107 
108 	/* Backward compatibility -- handle "-" meaning stdin. */
109 	special = 0;
110 	if (strcmp(file1 = argv[0], "-") == 0) {
111 		special = 1;
112 		fd1 = 0;
113 		file1 = "stdin";
114 	}
115 	else if ((fd1 = open(file1, O_RDONLY, 0)) < 0) {
116 		if (!sflag)
117 			err(ERR_EXIT, "%s", file1);
118 		else
119 			exit(1);
120 	}
121 	if (strcmp(file2 = argv[1], "-") == 0) {
122 		if (special)
123 			errx(ERR_EXIT,
124 				"standard input may only be specified once");
125 		special = 1;
126 		fd2 = 0;
127 		file2 = "stdin";
128 	}
129 	else if ((fd2 = open(file2, O_RDONLY, 0)) < 0) {
130 		if (!sflag)
131 			err(ERR_EXIT, "%s", file2);
132 		else
133 			exit(1);
134 	}
135 
136 	skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
137 	skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
138 
139 	if (!special) {
140 		if (fstat(fd1, &sb1)) {
141 			if (!sflag)
142 				err(ERR_EXIT, "%s", file1);
143 			else
144 				exit(1);
145 		}
146 		if (!S_ISREG(sb1.st_mode))
147 			special = 1;
148 		else {
149 			if (fstat(fd2, &sb2)) {
150 				if (!sflag)
151 					err(ERR_EXIT, "%s", file2);
152 				else
153 					exit(1);
154 			}
155 			if (!S_ISREG(sb2.st_mode))
156 				special = 1;
157 		}
158 	}
159 
160 	if (special)
161 		c_special(fd1, file1, skip1, fd2, file2, skip2);
162 	else {
163 		if (zflag && sb1.st_size != sb2.st_size) {
164 			if (!sflag)
165 				(void) printf("%s %s differ: size\n",
166 				    file1, file2);
167 			exit(DIFF_EXIT);
168 		}
169 		c_regular(fd1, file1, skip1, sb1.st_size,
170 		    fd2, file2, skip2, sb2.st_size);
171 	}
172 	exit(0);
173 }
174 
175 static void
176 usage()
177 {
178 
179 	(void)fprintf(stderr,
180 	    "usage: cmp [-l | -s | -x] [-z] file1 file2 [skip1 [skip2]]\n");
181 	exit(ERR_EXIT);
182 }
183