cmp.c revision 87241 
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#include <sys/cdefs.h>
35
36__FBSDID("$FreeBSD: head/usr.bin/cmp/cmp.c 87241 2001-12-02 23:29:26Z markm $");
37
38#ifndef lint
39static const char copyright[] =
40"@(#) Copyright (c) 1987, 1990, 1993, 1994\n\
41	The Regents of the University of California.  All rights reserved.\n";
42#endif
43
44#ifndef lint
45static const char sccsid[] = "@(#)cmp.c	8.3 (Berkeley) 4/2/94";
46#endif
47
48#include <sys/types.h>
49#include <sys/stat.h>
50
51#include <err.h>
52#include <fcntl.h>
53#include <stdio.h>
54#include <stdlib.h>
55#include <string.h>
56#include <unistd.h>
57
58#include "extern.h"
59
60int	lflag, sflag, xflag, zflag;
61
62static void usage __P((void));
63
64int
65main(argc, argv)
66	int argc;
67	char *argv[];
68{
69	struct stat sb1, sb2;
70	off_t skip1, skip2;
71	int ch, fd1, fd2, special;
72	const char *file1, *file2;
73
74	while ((ch = getopt(argc, argv, "-lsxz")) != -1)
75		switch (ch) {
76		case 'l':		/* print all differences */
77			lflag = 1;
78			break;
79		case 's':		/* silent run */
80			sflag = 1;
81			zflag = 1;
82			break;
83		case 'x':		/* hex output */
84			lflag = 1;
85			xflag = 1;
86			break;
87		case 'z':		/* compare size first */
88			zflag = 1;
89			break;
90		case '-':		/* stdin (must be after options) */
91			--optind;
92			goto endargs;
93		case '?':
94		default:
95			usage();
96		}
97endargs:
98	argv += optind;
99	argc -= optind;
100
101	if (lflag && sflag)
102		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
103
104	if (argc < 2 || argc > 4)
105		usage();
106
107	/* Backward compatibility -- handle "-" meaning stdin. */
108	special = 0;
109	if (strcmp(file1 = argv[0], "-") == 0) {
110		special = 1;
111		fd1 = 0;
112		file1 = "stdin";
113	}
114	else if ((fd1 = open(file1, O_RDONLY, 0)) < 0) {
115		if (!sflag)
116			err(ERR_EXIT, "%s", file1);
117		else
118			exit(1);
119	}
120	if (strcmp(file2 = argv[1], "-") == 0) {
121		if (special)
122			errx(ERR_EXIT,
123				"standard input may only be specified once");
124		special = 1;
125		fd2 = 0;
126		file2 = "stdin";
127	}
128	else if ((fd2 = open(file2, O_RDONLY, 0)) < 0) {
129		if (!sflag)
130			err(ERR_EXIT, "%s", file2);
131		else
132			exit(1);
133	}
134
135	skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
136	skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
137
138	if (!special) {
139		if (fstat(fd1, &sb1)) {
140			if (!sflag)
141				err(ERR_EXIT, "%s", file1);
142			else
143				exit(1);
144		}
145		if (!S_ISREG(sb1.st_mode))
146			special = 1;
147		else {
148			if (fstat(fd2, &sb2)) {
149				if (!sflag)
150					err(ERR_EXIT, "%s", file2);
151				else
152					exit(1);
153			}
154			if (!S_ISREG(sb2.st_mode))
155				special = 1;
156		}
157	}
158
159	if (special)
160		c_special(fd1, file1, skip1, fd2, file2, skip2);
161	else {
162		if (zflag && sb1.st_size != sb2.st_size) {
163			if (!sflag)
164				(void) printf("%s %s differ: size\n",
165				    file1, file2);
166			exit(DIFF_EXIT);
167		}
168		c_regular(fd1, file1, skip1, sb1.st_size,
169		    fd2, file2, skip2, sb2.st_size);
170	}
171	exit(0);
172}
173
174static void
175usage()
176{
177
178	(void)fprintf(stderr,
179	    "usage: cmp [-l | -s | -x] [-z] file1 file2 [skip1 [skip2]]\n");
180	exit(ERR_EXIT);
181}
182