cmp.c revision 149388 
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 149388 2005-08-23 13:13:13Z brian $");
48
49#include <sys/types.h>
50#include <sys/stat.h>
51
52#include <err.h>
53#include <errno.h>
54#include <fcntl.h>
55#include <stdio.h>
56#include <stdlib.h>
57#include <string.h>
58#include <unistd.h>
59
60#include "extern.h"
61
62int	lflag, sflag, xflag, zflag;
63
64static void usage(void);
65
66int
67main(int argc, char *argv[])
68{
69	struct stat sb1, sb2;
70	off_t skip1, skip2;
71	int ch, fd1, fd2, oflag, special;
72	const char *file1, *file2;
73
74	oflag = O_RDONLY;
75	while ((ch = getopt(argc, argv, "hlsxz")) != -1)
76		switch (ch) {
77		case 'h':		/* Don't follow symlinks */
78			oflag |= O_NOFOLLOW;
79			break;
80		case 'l':		/* print all differences */
81			lflag = 1;
82			break;
83		case 's':		/* silent run */
84			sflag = 1;
85			zflag = 1;
86			break;
87		case 'x':		/* hex output */
88			lflag = 1;
89			xflag = 1;
90			break;
91		case 'z':		/* compare size first */
92			zflag = 1;
93			break;
94		case '?':
95		default:
96			usage();
97		}
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, oflag, 0)) < 0 && errno != EMLINK) {
115		if (!sflag)
116			err(ERR_EXIT, "%s", file1);
117		else
118			exit(ERR_EXIT);
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, oflag, 0)) < 0 && errno != EMLINK) {
129		if (!sflag)
130			err(ERR_EXIT, "%s", file2);
131		else
132			exit(ERR_EXIT);
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 (fd1 == -1) {
139		if (fd2 == -1) {
140			c_link(file1, skip1, file2, skip2);
141			exit(0);
142		} else if (!sflag)
143			errx(ERR_EXIT, "%s: Not a symbolic link", file2);
144		else
145			exit(ERR_EXIT);
146	} else if (fd2 == -1) {
147		if (!sflag)
148			errx(ERR_EXIT, "%s: Not a symbolic link", file1);
149		else
150			exit(ERR_EXIT);
151	}
152
153	if (!special) {
154		if (fstat(fd1, &sb1)) {
155			if (!sflag)
156				err(ERR_EXIT, "%s", file1);
157			else
158				exit(ERR_EXIT);
159		}
160		if (!S_ISREG(sb1.st_mode))
161			special = 1;
162		else {
163			if (fstat(fd2, &sb2)) {
164				if (!sflag)
165					err(ERR_EXIT, "%s", file2);
166				else
167					exit(ERR_EXIT);
168			}
169			if (!S_ISREG(sb2.st_mode))
170				special = 1;
171		}
172	}
173
174	if (special)
175		c_special(fd1, file1, skip1, fd2, file2, skip2);
176	else {
177		if (zflag && sb1.st_size != sb2.st_size) {
178			if (!sflag)
179				(void) printf("%s %s differ: size\n",
180				    file1, file2);
181			exit(DIFF_EXIT);
182		}
183		c_regular(fd1, file1, skip1, sb1.st_size,
184		    fd2, file2, skip2, sb2.st_size);
185	}
186	exit(0);
187}
188
189static void
190usage(void)
191{
192
193	(void)fprintf(stderr,
194	    "usage: cmp [-l | -s | -x] [-hz] file1 file2 [skip1 [skip2]]\n");
195	exit(ERR_EXIT);
196}
197