cmp.c revision 97984 
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
35static 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
42static char sccsid[] = "@(#)cmp.c	8.3 (Berkeley) 4/2/94";
43#endif
44#endif
45
46#include <sys/cdefs.h>
47__FBSDID("$FreeBSD: head/usr.bin/cmp/cmp.c 97984 2002-06-07 02:30:56Z tjr $");
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
61int	lflag, sflag, xflag, zflag;
62
63static void usage(void);
64
65int
66main(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		}
98endargs:
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(ERR_EXIT);
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(ERR_EXIT);
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(ERR_EXIT);
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(ERR_EXIT);
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
175static void
176usage()
177{
178
179	(void)fprintf(stderr,
180	    "usage: cmp [-l | -s | -x] [-z] file1 file2 [skip1 [skip2]]\n");
181	exit(ERR_EXIT);
182}
183