xref: /freebsd/usr.bin/cmp/cmp.c (revision d9a42747950146bf03cda7f6e25d219253f8a57a)
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 #ifndef lint
33 static 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
40 static char sccsid[] = "@(#)cmp.c	8.3 (Berkeley) 4/2/94";
41 #endif
42 #endif
43 
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
46 
47 #include <sys/types.h>
48 #include <sys/stat.h>
49 
50 #include <capsicum_helpers.h>
51 #include <err.h>
52 #include <errno.h>
53 #include <fcntl.h>
54 #include <getopt.h>
55 #include <nl_types.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <unistd.h>
60 
61 #include <libutil.h>
62 
63 #include "extern.h"
64 
65 bool	bflag, lflag, sflag, xflag, zflag;
66 
67 static const struct option long_opts[] =
68 {
69 	{"print-bytes",	no_argument,		NULL, 'b'},
70 	{"ignore-initial", required_argument,	NULL, 'i'},
71 	{"verbose",	no_argument,		NULL, 'l'},
72 	{"bytes",	required_argument,	NULL, 'n'},
73 	{"silent",	no_argument,		NULL, 's'},
74 	{"quiet",	no_argument,		NULL, 's'},
75 	{NULL,		no_argument,		NULL, 0}
76 };
77 
78 #ifdef SIGINFO
79 volatile sig_atomic_t info;
80 
81 static void
82 siginfo(int signo)
83 {
84 
85 	info = signo;
86 }
87 #endif
88 
89 static void usage(void);
90 
91 static bool
92 parse_iskipspec(char *spec, off_t *skip1, off_t *skip2)
93 {
94 	char *colon;
95 
96 	colon = strchr(spec, ':');
97 	if (colon != NULL)
98 		*colon++ = '\0';
99 
100 	if (expand_number(spec, skip1) < 0)
101 		return (false);
102 
103 	if (colon != NULL)
104 		return (expand_number(colon, skip2) == 0);
105 
106 	*skip2 = *skip1;
107 	return (true);
108 }
109 
110 int
111 main(int argc, char *argv[])
112 {
113 	struct stat sb1, sb2;
114 	off_t skip1, skip2, limit;
115 	int ch, fd1, fd2, oflag;
116 	bool special;
117 	const char *file1, *file2;
118 
119 	limit = skip1 = skip2 = 0;
120 	oflag = O_RDONLY;
121 	while ((ch = getopt_long(argc, argv, "+bhi:ln:sxz", long_opts, NULL)) != -1)
122 		switch (ch) {
123 		case 'b':		/* Print bytes */
124 			bflag = true;
125 			break;
126 		case 'h':		/* Don't follow symlinks */
127 			oflag |= O_NOFOLLOW;
128 			break;
129 		case 'i':
130 			if (!parse_iskipspec(optarg, &skip1, &skip2)) {
131 				fprintf(stderr,
132 				    "Invalid --ignore-initial: %s\n",
133 				    optarg);
134 				usage();
135 			}
136 			break;
137 		case 'l':		/* print all differences */
138 			lflag = true;
139 			break;
140 		case 'n':		/* Limit */
141 			if (expand_number(optarg, &limit) < 0 || limit < 0) {
142 				fprintf(stderr, "Invalid --bytes: %s\n",
143 				    optarg);
144 				usage();
145 			}
146 			break;
147 		case 's':		/* silent run */
148 			sflag = true;
149 			break;
150 		case 'x':		/* hex output */
151 			lflag = true;
152 			xflag = true;
153 			break;
154 		case 'z':		/* compare size first */
155 			zflag = true;
156 			break;
157 		case '?':
158 		default:
159 			usage();
160 		}
161 	argv += optind;
162 	argc -= optind;
163 
164 	if (lflag && sflag)
165 		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
166 
167 	if (argc < 2 || argc > 4)
168 		usage();
169 
170 	/* Don't limit rights on stdin since it may be one of the inputs. */
171 	if (caph_limit_stream(STDOUT_FILENO, CAPH_WRITE | CAPH_IGNORE_EBADF))
172 		err(ERR_EXIT, "unable to limit rights on stdout");
173 	if (caph_limit_stream(STDERR_FILENO, CAPH_WRITE | CAPH_IGNORE_EBADF))
174 		err(ERR_EXIT, "unable to limit rights on stderr");
175 
176 	/* Backward compatibility -- handle "-" meaning stdin. */
177 	special = false;
178 	if (strcmp(file1 = argv[0], "-") == 0) {
179 		special = true;
180 		fd1 = STDIN_FILENO;
181 		file1 = "stdin";
182 	} else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
183 		if (!sflag)
184 			err(ERR_EXIT, "%s", file1);
185 		else
186 			exit(ERR_EXIT);
187 	}
188 	if (strcmp(file2 = argv[1], "-") == 0) {
189 		if (special)
190 			errx(ERR_EXIT,
191 				"standard input may only be specified once");
192 		special = true;
193 		fd2 = STDIN_FILENO;
194 		file2 = "stdin";
195 	} else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
196 		if (!sflag)
197 			err(ERR_EXIT, "%s", file2);
198 		else
199 			exit(ERR_EXIT);
200 	}
201 
202 	if (argc > 2 && expand_number(argv[2], &skip1) < 0) {
203 		fprintf(stderr, "Invalid skip1: %s\n", argv[2]);
204 		usage();
205 	}
206 
207 	if (argc == 4 && expand_number(argv[3], &skip2) < 0) {
208 		fprintf(stderr, "Invalid skip2: %s\n", argv[3]);
209 		usage();
210 	}
211 
212 	if (sflag && skip1 == 0 && skip2 == 0)
213 		zflag = true;
214 
215 	if (fd1 == -1) {
216 		if (fd2 == -1) {
217 			c_link(file1, skip1, file2, skip2, limit);
218 			exit(0);
219 		} else if (!sflag)
220 			errx(ERR_EXIT, "%s: Not a symbolic link", file2);
221 		else
222 			exit(ERR_EXIT);
223 	} else if (fd2 == -1) {
224 		if (!sflag)
225 			errx(ERR_EXIT, "%s: Not a symbolic link", file1);
226 		else
227 			exit(ERR_EXIT);
228 	}
229 
230 	/* FD rights are limited in c_special() and c_regular(). */
231 	caph_cache_catpages();
232 
233 	if (!special) {
234 		if (fstat(fd1, &sb1)) {
235 			if (!sflag)
236 				err(ERR_EXIT, "%s", file1);
237 			else
238 				exit(ERR_EXIT);
239 		}
240 		if (!S_ISREG(sb1.st_mode))
241 			special = true;
242 		else {
243 			if (fstat(fd2, &sb2)) {
244 				if (!sflag)
245 					err(ERR_EXIT, "%s", file2);
246 				else
247 					exit(ERR_EXIT);
248 			}
249 			if (!S_ISREG(sb2.st_mode))
250 				special = true;
251 		}
252 	}
253 
254 #ifdef SIGINFO
255 	(void)signal(SIGINFO, siginfo);
256 #endif
257 	if (special)
258 		c_special(fd1, file1, skip1, fd2, file2, skip2, limit);
259 	else {
260 		if (zflag && sb1.st_size != sb2.st_size) {
261 			if (!sflag)
262 				(void) printf("%s %s differ: size\n",
263 				    file1, file2);
264 			exit(DIFF_EXIT);
265 		}
266 		c_regular(fd1, file1, skip1, sb1.st_size,
267 		    fd2, file2, skip2, sb2.st_size, limit);
268 	}
269 	exit(0);
270 }
271 
272 static void
273 usage(void)
274 {
275 
276 	(void)fprintf(stderr,
277 	    "usage: cmp [-l | -s | -x] [-hz] file1 file2 [skip1 [skip2]]\n");
278 	exit(ERR_EXIT);
279 }
280