cmp.c revision 330897 
1/*
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1987, 1990, 1993, 1994
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 4. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#ifndef lint
33static const char copyright[] =
34"@(#) Copyright (c) 1987, 1990, 1993, 1994\n\
35	The Regents of the University of California.  All rights reserved.\n";
36#endif
37
38#if 0
39#ifndef lint
40static char sccsid[] = "@(#)cmp.c	8.3 (Berkeley) 4/2/94";
41#endif
42#endif
43
44#include <sys/cdefs.h>
45__FBSDID("$FreeBSD: stable/11/usr.bin/cmp/cmp.c 330897 2018-03-14 03:19:51Z eadler $");
46
47#include <sys/types.h>
48#include <sys/stat.h>
49
50#include <err.h>
51#include <errno.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(void);
63
64int
65main(int argc, char *argv[])
66{
67	struct stat sb1, sb2;
68	off_t skip1, skip2;
69	int ch, fd1, fd2, oflag, special;
70	const char *file1, *file2;
71
72	oflag = O_RDONLY;
73	while ((ch = getopt(argc, argv, "hlsxz")) != -1)
74		switch (ch) {
75		case 'h':		/* Don't follow symlinks */
76			oflag |= O_NOFOLLOW;
77			break;
78		case 'l':		/* print all differences */
79			lflag = 1;
80			break;
81		case 's':		/* silent run */
82			sflag = 1;
83			zflag = 1;
84			break;
85		case 'x':		/* hex output */
86			lflag = 1;
87			xflag = 1;
88			break;
89		case 'z':		/* compare size first */
90			zflag = 1;
91			break;
92		case '?':
93		default:
94			usage();
95		}
96	argv += optind;
97	argc -= optind;
98
99	if (lflag && sflag)
100		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
101
102	if (argc < 2 || argc > 4)
103		usage();
104
105	/* Backward compatibility -- handle "-" meaning stdin. */
106	special = 0;
107	if (strcmp(file1 = argv[0], "-") == 0) {
108		special = 1;
109		fd1 = 0;
110		file1 = "stdin";
111	}
112	else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
113		if (!sflag)
114			err(ERR_EXIT, "%s", file1);
115		else
116			exit(ERR_EXIT);
117	}
118	if (strcmp(file2 = argv[1], "-") == 0) {
119		if (special)
120			errx(ERR_EXIT,
121				"standard input may only be specified once");
122		special = 1;
123		fd2 = 0;
124		file2 = "stdin";
125	}
126	else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
127		if (!sflag)
128			err(ERR_EXIT, "%s", file2);
129		else
130			exit(ERR_EXIT);
131	}
132
133	skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
134	skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
135
136	if (fd1 == -1) {
137		if (fd2 == -1) {
138			c_link(file1, skip1, file2, skip2);
139			exit(0);
140		} else if (!sflag)
141			errx(ERR_EXIT, "%s: Not a symbolic link", file2);
142		else
143			exit(ERR_EXIT);
144	} else if (fd2 == -1) {
145		if (!sflag)
146			errx(ERR_EXIT, "%s: Not a symbolic link", file1);
147		else
148			exit(ERR_EXIT);
149	}
150
151	if (!special) {
152		if (fstat(fd1, &sb1)) {
153			if (!sflag)
154				err(ERR_EXIT, "%s", file1);
155			else
156				exit(ERR_EXIT);
157		}
158		if (!S_ISREG(sb1.st_mode))
159			special = 1;
160		else {
161			if (fstat(fd2, &sb2)) {
162				if (!sflag)
163					err(ERR_EXIT, "%s", file2);
164				else
165					exit(ERR_EXIT);
166			}
167			if (!S_ISREG(sb2.st_mode))
168				special = 1;
169		}
170	}
171
172	if (special)
173		c_special(fd1, file1, skip1, fd2, file2, skip2);
174	else {
175		if (zflag && sb1.st_size != sb2.st_size) {
176			if (!sflag)
177				(void) printf("%s %s differ: size\n",
178				    file1, file2);
179			exit(DIFF_EXIT);
180		}
181		c_regular(fd1, file1, skip1, sb1.st_size,
182		    fd2, file2, skip2, sb2.st_size);
183	}
184	exit(0);
185}
186
187static void
188usage(void)
189{
190
191	(void)fprintf(stderr,
192	    "usage: cmp [-l | -s | -x] [-hz] file1 file2 [skip1 [skip2]]\n");
193	exit(ERR_EXIT);
194}
195