1/*      $OpenBSD: cmp.c,v 1.19 2021/10/24 21:24:16 deraadt Exp $      */
2/*      $NetBSD: cmp.c,v 1.7 1995/09/08 03:22:56 tls Exp $      */
3
4/*
5 * Copyright (c) 1987, 1990, 1993, 1994
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include <sys/types.h>
34#include <sys/stat.h>
35
36#include <err.h>
37#include <errno.h>
38#include <fcntl.h>
39#include <limits.h>
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43#include <unistd.h>
44
45#include "extern.h"
46
47int	lflag, sflag;
48
49static off_t get_skip(const char *, const char *);
50static void __dead usage(void);
51
52int
53main(int argc, char *argv[])
54{
55	struct stat sb1, sb2;
56	off_t skip1, skip2;
57	int ch, fd1, fd2, special;
58	char *file1, *file2;
59
60	if (pledge("stdio rpath", NULL) == -1)
61		err(ERR_EXIT, "pledge");
62
63	while ((ch = getopt(argc, argv, "ls")) != -1)
64		switch (ch) {
65		case 'l':		/* print all differences */
66			lflag = 1;
67			break;
68		case 's':		/* silent run */
69			sflag = 1;
70			break;
71		default:
72			usage();
73		}
74
75	argv += optind;
76	argc -= optind;
77
78	if (lflag && sflag)
79		errx(ERR_EXIT, "only one of -l and -s may be specified");
80
81	if (argc < 2 || argc > 4)
82		usage();
83
84	/* Backward compatibility -- handle "-" meaning stdin. */
85	special = 0;
86	if (strcmp(file1 = argv[0], "-") == 0) {
87		special = 1;
88		fd1 = 0;
89		file1 = "stdin";
90	} else if ((fd1 = open(file1, O_RDONLY)) == -1)
91		fatal("%s", file1);
92	if (strcmp(file2 = argv[1], "-") == 0) {
93		if (special)
94			fatalx("standard input may only be specified once");
95		special = 1;
96		fd2 = 0;
97		file2 = "stdin";
98	} else if ((fd2 = open(file2, O_RDONLY)) == -1)
99		fatal("%s", file2);
100
101	if (pledge("stdio", NULL) == -1)
102		err(ERR_EXIT, "pledge");
103
104	skip1 = (argc > 2) ? get_skip(argv[2], "skip1") : 0;
105	skip2 = (argc == 4) ? get_skip(argv[3], "skip2") : 0;
106
107	if (!special) {
108		if (fstat(fd1, &sb1) == -1)
109			fatal("%s", file1);
110		if (!S_ISREG(sb1.st_mode))
111			special = 1;
112		else {
113			if (fstat(fd2, &sb2) == -1)
114				fatal("%s", file2);
115			if (!S_ISREG(sb2.st_mode))
116				special = 1;
117		}
118	}
119
120	if (special)
121		c_special(fd1, file1, skip1, fd2, file2, skip2);
122	else
123		c_regular(fd1, file1, skip1, sb1.st_size,
124		    fd2, file2, skip2, sb2.st_size);
125	return 0;
126}
127
128static off_t
129get_skip(const char *arg, const char *name)
130{
131	off_t skip;
132	char *ep;
133
134	errno = 0;
135	skip = strtoll(arg, &ep, 0);
136	if (arg[0] == '\0' || *ep != '\0')
137		fatalx("%s is invalid: %s", name, arg);
138	if (skip < 0)
139		fatalx("%s is too small: %s", name, arg);
140	if (skip == LLONG_MAX && errno == ERANGE)
141		fatalx("%s is too large: %s", name, arg);
142	return skip;
143}
144
145static void __dead
146usage(void)
147{
148
149	(void)fprintf(stderr,
150	    "usage: cmp [-l | -s] file1 file2 [skip1 [skip2]]\n");
151	exit(ERR_EXIT);
152}
153