cmp.c revision 63843 
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: head/usr.bin/cmp/cmp.c 63843 2000-07-25 13:01:34Z sheldonh $
34 *
35 */
36
37#ifndef lint
38static 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
44static 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
59int	lflag, sflag, xflag, zflag;
60
61static void usage __P((void));
62
63int
64main(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, "-lsxz")) != -1)
74		switch (ch) {
75		case 'l':		/* print all differences */
76			lflag = 1;
77			break;
78		case 's':		/* silent run */
79			sflag = 1;
80			zflag = 1;
81			break;
82		case 'x':		/* hex output */
83			lflag = 1;
84			xflag = 1;
85			break;
86		case 'z':		/* compare size first */
87			zflag = 1;
88			break;
89		case '-':		/* stdin (must be after options) */
90			--optind;
91			goto endargs;
92		case '?':
93		default:
94			usage();
95		}
96endargs:
97	argv += optind;
98	argc -= optind;
99
100	if (lflag && sflag)
101		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
102
103	if (argc < 2 || argc > 4)
104		usage();
105
106	/* Backward compatibility -- handle "-" meaning stdin. */
107	special = 0;
108	if (strcmp(file1 = argv[0], "-") == 0) {
109		special = 1;
110		fd1 = 0;
111		file1 = "stdin";
112	}
113	else if ((fd1 = open(file1, O_RDONLY, 0)) < 0) {
114		if (!sflag)
115			err(ERR_EXIT, "%s", file1);
116		else
117			exit(1);
118	}
119	if (strcmp(file2 = argv[1], "-") == 0) {
120		if (special)
121			errx(ERR_EXIT,
122				"standard input may only be specified once");
123		special = 1;
124		fd2 = 0;
125		file2 = "stdin";
126	}
127	else if ((fd2 = open(file2, O_RDONLY, 0)) < 0) {
128		if (!sflag)
129			err(ERR_EXIT, "%s", file2);
130		else
131			exit(1);
132	}
133
134	skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
135	skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
136
137	if (!special) {
138		if (fstat(fd1, &sb1)) {
139			if (!sflag)
140				err(ERR_EXIT, "%s", file1);
141			else
142				exit(1);
143		}
144		if (!S_ISREG(sb1.st_mode))
145			special = 1;
146		else {
147			if (fstat(fd2, &sb2)) {
148				if (!sflag)
149					err(ERR_EXIT, "%s", file2);
150				else
151					exit(1);
152			}
153			if (!S_ISREG(sb2.st_mode))
154				special = 1;
155		}
156	}
157
158	if (special)
159		c_special(fd1, file1, skip1, fd2, file2, skip2);
160	else {
161		if (zflag && sb1.st_size != sb2.st_size) {
162			if (!sflag)
163				(void) printf("%s %s differ: size\n",
164				    file1, file2);
165			exit(DIFF_EXIT);
166		}
167		c_regular(fd1, file1, skip1, sb1.st_size,
168		    fd2, file2, skip2, sb2.st_size);
169	}
170	exit(0);
171}
172
173static void
174usage()
175{
176
177	(void)fprintf(stderr,
178	    "usage: cmp [-l | -s | -x] [-z] file1 file2 [skip1 [skip2]]\n");
179	exit(ERR_EXIT);
180}
181