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 * 3. 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#include <sys/types.h>
33#include <sys/stat.h>
34
35#include <capsicum_helpers.h>
36#include <err.h>
37#include <errno.h>
38#include <fcntl.h>
39#include <getopt.h>
40#include <nl_types.h>
41#include <stdio.h>
42#include <stdlib.h>
43#include <string.h>
44#include <unistd.h>
45
46#include <libutil.h>
47
48#include "extern.h"
49
50bool	bflag, lflag, sflag, xflag, zflag;
51
52static const struct option long_opts[] =
53{
54	{"print-bytes",	no_argument,		NULL, 'b'},
55	{"ignore-initial", required_argument,	NULL, 'i'},
56	{"verbose",	no_argument,		NULL, 'l'},
57	{"bytes",	required_argument,	NULL, 'n'},
58	{"silent",	no_argument,		NULL, 's'},
59	{"quiet",	no_argument,		NULL, 's'},
60	{NULL,		no_argument,		NULL, 0}
61};
62
63#ifdef SIGINFO
64volatile sig_atomic_t info;
65
66static void
67siginfo(int signo)
68{
69
70	info = signo;
71}
72#endif
73
74static void usage(void) __dead2;
75
76static bool
77parse_iskipspec(char *spec, off_t *skip1, off_t *skip2)
78{
79	char *colon;
80
81	colon = strchr(spec, ':');
82	if (colon != NULL)
83		*colon++ = '\0';
84
85	if (expand_number(spec, skip1) < 0)
86		return (false);
87
88	if (colon != NULL)
89		return (expand_number(colon, skip2) == 0);
90
91	*skip2 = *skip1;
92	return (true);
93}
94
95int
96main(int argc, char *argv[])
97{
98	struct stat sb1, sb2;
99	off_t skip1, skip2, limit;
100	int ch, fd1, fd2, oflag;
101	bool special;
102	const char *file1, *file2;
103
104	limit = skip1 = skip2 = 0;
105	oflag = O_RDONLY;
106	while ((ch = getopt_long(argc, argv, "+bhi:ln:sxz", long_opts, NULL)) != -1)
107		switch (ch) {
108		case 'b':		/* Print bytes */
109			bflag = true;
110			break;
111		case 'h':		/* Don't follow symlinks */
112			oflag |= O_NOFOLLOW;
113			break;
114		case 'i':
115			if (!parse_iskipspec(optarg, &skip1, &skip2)) {
116				fprintf(stderr,
117				    "Invalid --ignore-initial: %s\n",
118				    optarg);
119				usage();
120			}
121			break;
122		case 'l':		/* print all differences */
123			lflag = true;
124			break;
125		case 'n':		/* Limit */
126			if (expand_number(optarg, &limit) < 0 || limit < 0) {
127				fprintf(stderr, "Invalid --bytes: %s\n",
128				    optarg);
129				usage();
130			}
131			break;
132		case 's':		/* silent run */
133			sflag = true;
134			break;
135		case 'x':		/* hex output */
136			lflag = true;
137			xflag = true;
138			break;
139		case 'z':		/* compare size first */
140			zflag = true;
141			break;
142		case '?':
143		default:
144			usage();
145		}
146	argv += optind;
147	argc -= optind;
148
149	if (lflag && sflag)
150		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
151
152	if (argc < 2 || argc > 4)
153		usage();
154
155	/* Don't limit rights on stdin since it may be one of the inputs. */
156	if (caph_limit_stream(STDOUT_FILENO, CAPH_WRITE | CAPH_IGNORE_EBADF))
157		err(ERR_EXIT, "unable to limit rights on stdout");
158	if (caph_limit_stream(STDERR_FILENO, CAPH_WRITE | CAPH_IGNORE_EBADF))
159		err(ERR_EXIT, "unable to limit rights on stderr");
160
161	/* Backward compatibility -- handle "-" meaning stdin. */
162	special = false;
163	if (strcmp(file1 = argv[0], "-") == 0) {
164		special = true;
165		fd1 = STDIN_FILENO;
166		file1 = "stdin";
167	} else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
168		if (!sflag)
169			err(ERR_EXIT, "%s", file1);
170		else
171			exit(ERR_EXIT);
172	}
173	if (strcmp(file2 = argv[1], "-") == 0) {
174		if (special)
175			errx(ERR_EXIT,
176				"standard input may only be specified once");
177		special = true;
178		fd2 = STDIN_FILENO;
179		file2 = "stdin";
180	} else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
181		if (!sflag)
182			err(ERR_EXIT, "%s", file2);
183		else
184			exit(ERR_EXIT);
185	}
186
187	if (argc > 2 && expand_number(argv[2], &skip1) < 0) {
188		fprintf(stderr, "Invalid skip1: %s\n", argv[2]);
189		usage();
190	}
191
192	if (argc == 4 && expand_number(argv[3], &skip2) < 0) {
193		fprintf(stderr, "Invalid skip2: %s\n", argv[3]);
194		usage();
195	}
196
197	if (sflag && skip1 == 0 && skip2 == 0)
198		zflag = true;
199
200	if (fd1 == -1) {
201		if (fd2 == -1) {
202			c_link(file1, skip1, file2, skip2, limit);
203			exit(0);
204		} else if (!sflag)
205			errx(ERR_EXIT, "%s: Not a symbolic link", file2);
206		else
207			exit(ERR_EXIT);
208	} else if (fd2 == -1) {
209		if (!sflag)
210			errx(ERR_EXIT, "%s: Not a symbolic link", file1);
211		else
212			exit(ERR_EXIT);
213	}
214
215	/* FD rights are limited in c_special() and c_regular(). */
216	caph_cache_catpages();
217
218	if (!special) {
219		if (fstat(fd1, &sb1)) {
220			if (!sflag)
221				err(ERR_EXIT, "%s", file1);
222			else
223				exit(ERR_EXIT);
224		}
225		if (!S_ISREG(sb1.st_mode))
226			special = true;
227		else {
228			if (fstat(fd2, &sb2)) {
229				if (!sflag)
230					err(ERR_EXIT, "%s", file2);
231				else
232					exit(ERR_EXIT);
233			}
234			if (!S_ISREG(sb2.st_mode))
235				special = true;
236		}
237	}
238
239#ifdef SIGINFO
240	(void)signal(SIGINFO, siginfo);
241#endif
242	if (special)
243		c_special(fd1, file1, skip1, fd2, file2, skip2, limit);
244	else {
245		if (zflag && sb1.st_size != sb2.st_size) {
246			if (!sflag)
247				(void) printf("%s %s differ: size\n",
248				    file1, file2);
249			exit(DIFF_EXIT);
250		}
251		c_regular(fd1, file1, skip1, sb1.st_size,
252		    fd2, file2, skip2, sb2.st_size, limit);
253	}
254	exit(0);
255}
256
257static void
258usage(void)
259{
260
261	(void)fprintf(stderr,
262	    "usage: cmp [-l | -s | -x] [-hz] file1 file2 [skip1 [skip2]]\n");
263	exit(ERR_EXIT);
264}
265