cmp.c revision 331722 
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 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#ifndef lint
31static const char copyright[] =
32"@(#) Copyright (c) 1987, 1990, 1993, 1994\n\
33	The Regents of the University of California.  All rights reserved.\n";
34#endif
35
36#if 0
37#ifndef lint
38static char sccsid[] = "@(#)cmp.c	8.3 (Berkeley) 4/2/94";
39#endif
40#endif
41
42#include <sys/cdefs.h>
43__FBSDID("$FreeBSD: stable/11/usr.bin/cmp/cmp.c 331722 2018-03-29 02:50:57Z eadler $");
44
45#include <sys/types.h>
46#include <sys/stat.h>
47
48#include <err.h>
49#include <errno.h>
50#include <fcntl.h>
51#include <stdio.h>
52#include <stdlib.h>
53#include <string.h>
54#include <unistd.h>
55
56#include "extern.h"
57
58int	lflag, sflag, xflag, zflag;
59
60static void usage(void);
61
62int
63main(int argc, char *argv[])
64{
65	struct stat sb1, sb2;
66	off_t skip1, skip2;
67	int ch, fd1, fd2, oflag, special;
68	const char *file1, *file2;
69
70	oflag = O_RDONLY;
71	while ((ch = getopt(argc, argv, "hlsxz")) != -1)
72		switch (ch) {
73		case 'h':		/* Don't follow symlinks */
74			oflag |= O_NOFOLLOW;
75			break;
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 '?':
91		default:
92			usage();
93		}
94	argv += optind;
95	argc -= optind;
96
97	if (lflag && sflag)
98		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
99
100	if (argc < 2 || argc > 4)
101		usage();
102
103	/* Backward compatibility -- handle "-" meaning stdin. */
104	special = 0;
105	if (strcmp(file1 = argv[0], "-") == 0) {
106		special = 1;
107		fd1 = 0;
108		file1 = "stdin";
109	}
110	else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
111		if (!sflag)
112			err(ERR_EXIT, "%s", file1);
113		else
114			exit(ERR_EXIT);
115	}
116	if (strcmp(file2 = argv[1], "-") == 0) {
117		if (special)
118			errx(ERR_EXIT,
119				"standard input may only be specified once");
120		special = 1;
121		fd2 = 0;
122		file2 = "stdin";
123	}
124	else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
125		if (!sflag)
126			err(ERR_EXIT, "%s", file2);
127		else
128			exit(ERR_EXIT);
129	}
130
131	skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
132	skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
133
134	if (fd1 == -1) {
135		if (fd2 == -1) {
136			c_link(file1, skip1, file2, skip2);
137			exit(0);
138		} else if (!sflag)
139			errx(ERR_EXIT, "%s: Not a symbolic link", file2);
140		else
141			exit(ERR_EXIT);
142	} else if (fd2 == -1) {
143		if (!sflag)
144			errx(ERR_EXIT, "%s: Not a symbolic link", file1);
145		else
146			exit(ERR_EXIT);
147	}
148
149	if (!special) {
150		if (fstat(fd1, &sb1)) {
151			if (!sflag)
152				err(ERR_EXIT, "%s", file1);
153			else
154				exit(ERR_EXIT);
155		}
156		if (!S_ISREG(sb1.st_mode))
157			special = 1;
158		else {
159			if (fstat(fd2, &sb2)) {
160				if (!sflag)
161					err(ERR_EXIT, "%s", file2);
162				else
163					exit(ERR_EXIT);
164			}
165			if (!S_ISREG(sb2.st_mode))
166				special = 1;
167		}
168	}
169
170	if (special)
171		c_special(fd1, file1, skip1, fd2, file2, skip2);
172	else {
173		if (zflag && sb1.st_size != sb2.st_size) {
174			if (!sflag)
175				(void) printf("%s %s differ: size\n",
176				    file1, file2);
177			exit(DIFF_EXIT);
178		}
179		c_regular(fd1, file1, skip1, sb1.st_size,
180		    fd2, file2, skip2, sb2.st_size);
181	}
182	exit(0);
183}
184
185static void
186usage(void)
187{
188
189	(void)fprintf(stderr,
190	    "usage: cmp [-l | -s | -x] [-hz] file1 file2 [skip1 [skip2]]\n");
191	exit(ERR_EXIT);
192}
193