xref: /freebsd/usr.bin/cmp/cmp.c (revision 5b31cc94b10d4bb7109c6b27940a0fc76a44a331)
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 #endif
40 
41 #include <sys/cdefs.h>
42 #include <sys/types.h>
43 #include <sys/stat.h>
44 
45 #include <capsicum_helpers.h>
46 #include <err.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <getopt.h>
50 #include <nl_types.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <unistd.h>
55 
56 #include <libutil.h>
57 
58 #include "extern.h"
59 
60 bool	bflag, lflag, sflag, xflag, zflag;
61 
62 static const struct option long_opts[] =
63 {
64 	{"print-bytes",	no_argument,		NULL, 'b'},
65 	{"ignore-initial", required_argument,	NULL, 'i'},
66 	{"verbose",	no_argument,		NULL, 'l'},
67 	{"bytes",	required_argument,	NULL, 'n'},
68 	{"silent",	no_argument,		NULL, 's'},
69 	{"quiet",	no_argument,		NULL, 's'},
70 	{NULL,		no_argument,		NULL, 0}
71 };
72 
73 #ifdef SIGINFO
74 volatile sig_atomic_t info;
75 
76 static void
77 siginfo(int signo)
78 {
79 
80 	info = signo;
81 }
82 #endif
83 
84 static void usage(void) __dead2;
85 
86 static bool
87 parse_iskipspec(char *spec, off_t *skip1, off_t *skip2)
88 {
89 	char *colon;
90 
91 	colon = strchr(spec, ':');
92 	if (colon != NULL)
93 		*colon++ = '\0';
94 
95 	if (expand_number(spec, skip1) < 0)
96 		return (false);
97 
98 	if (colon != NULL)
99 		return (expand_number(colon, skip2) == 0);
100 
101 	*skip2 = *skip1;
102 	return (true);
103 }
104 
105 int
106 main(int argc, char *argv[])
107 {
108 	struct stat sb1, sb2;
109 	off_t skip1, skip2, limit;
110 	int ch, fd1, fd2, oflag;
111 	bool special;
112 	const char *file1, *file2;
113 
114 	limit = skip1 = skip2 = 0;
115 	oflag = O_RDONLY;
116 	while ((ch = getopt_long(argc, argv, "+bhi:ln:sxz", long_opts, NULL)) != -1)
117 		switch (ch) {
118 		case 'b':		/* Print bytes */
119 			bflag = true;
120 			break;
121 		case 'h':		/* Don't follow symlinks */
122 			oflag |= O_NOFOLLOW;
123 			break;
124 		case 'i':
125 			if (!parse_iskipspec(optarg, &skip1, &skip2)) {
126 				fprintf(stderr,
127 				    "Invalid --ignore-initial: %s\n",
128 				    optarg);
129 				usage();
130 			}
131 			break;
132 		case 'l':		/* print all differences */
133 			lflag = true;
134 			break;
135 		case 'n':		/* Limit */
136 			if (expand_number(optarg, &limit) < 0 || limit < 0) {
137 				fprintf(stderr, "Invalid --bytes: %s\n",
138 				    optarg);
139 				usage();
140 			}
141 			break;
142 		case 's':		/* silent run */
143 			sflag = true;
144 			break;
145 		case 'x':		/* hex output */
146 			lflag = true;
147 			xflag = true;
148 			break;
149 		case 'z':		/* compare size first */
150 			zflag = true;
151 			break;
152 		case '?':
153 		default:
154 			usage();
155 		}
156 	argv += optind;
157 	argc -= optind;
158 
159 	if (lflag && sflag)
160 		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
161 
162 	if (argc < 2 || argc > 4)
163 		usage();
164 
165 	/* Don't limit rights on stdin since it may be one of the inputs. */
166 	if (caph_limit_stream(STDOUT_FILENO, CAPH_WRITE | CAPH_IGNORE_EBADF))
167 		err(ERR_EXIT, "unable to limit rights on stdout");
168 	if (caph_limit_stream(STDERR_FILENO, CAPH_WRITE | CAPH_IGNORE_EBADF))
169 		err(ERR_EXIT, "unable to limit rights on stderr");
170 
171 	/* Backward compatibility -- handle "-" meaning stdin. */
172 	special = false;
173 	if (strcmp(file1 = argv[0], "-") == 0) {
174 		special = true;
175 		fd1 = STDIN_FILENO;
176 		file1 = "stdin";
177 	} else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
178 		if (!sflag)
179 			err(ERR_EXIT, "%s", file1);
180 		else
181 			exit(ERR_EXIT);
182 	}
183 	if (strcmp(file2 = argv[1], "-") == 0) {
184 		if (special)
185 			errx(ERR_EXIT,
186 				"standard input may only be specified once");
187 		special = true;
188 		fd2 = STDIN_FILENO;
189 		file2 = "stdin";
190 	} else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
191 		if (!sflag)
192 			err(ERR_EXIT, "%s", file2);
193 		else
194 			exit(ERR_EXIT);
195 	}
196 
197 	if (argc > 2 && expand_number(argv[2], &skip1) < 0) {
198 		fprintf(stderr, "Invalid skip1: %s\n", argv[2]);
199 		usage();
200 	}
201 
202 	if (argc == 4 && expand_number(argv[3], &skip2) < 0) {
203 		fprintf(stderr, "Invalid skip2: %s\n", argv[3]);
204 		usage();
205 	}
206 
207 	if (sflag && skip1 == 0 && skip2 == 0)
208 		zflag = true;
209 
210 	if (fd1 == -1) {
211 		if (fd2 == -1) {
212 			c_link(file1, skip1, file2, skip2, limit);
213 			exit(0);
214 		} else if (!sflag)
215 			errx(ERR_EXIT, "%s: Not a symbolic link", file2);
216 		else
217 			exit(ERR_EXIT);
218 	} else if (fd2 == -1) {
219 		if (!sflag)
220 			errx(ERR_EXIT, "%s: Not a symbolic link", file1);
221 		else
222 			exit(ERR_EXIT);
223 	}
224 
225 	/* FD rights are limited in c_special() and c_regular(). */
226 	caph_cache_catpages();
227 
228 	if (!special) {
229 		if (fstat(fd1, &sb1)) {
230 			if (!sflag)
231 				err(ERR_EXIT, "%s", file1);
232 			else
233 				exit(ERR_EXIT);
234 		}
235 		if (!S_ISREG(sb1.st_mode))
236 			special = true;
237 		else {
238 			if (fstat(fd2, &sb2)) {
239 				if (!sflag)
240 					err(ERR_EXIT, "%s", file2);
241 				else
242 					exit(ERR_EXIT);
243 			}
244 			if (!S_ISREG(sb2.st_mode))
245 				special = true;
246 		}
247 	}
248 
249 #ifdef SIGINFO
250 	(void)signal(SIGINFO, siginfo);
251 #endif
252 	if (special)
253 		c_special(fd1, file1, skip1, fd2, file2, skip2, limit);
254 	else {
255 		if (zflag && sb1.st_size != sb2.st_size) {
256 			if (!sflag)
257 				(void) printf("%s %s differ: size\n",
258 				    file1, file2);
259 			exit(DIFF_EXIT);
260 		}
261 		c_regular(fd1, file1, skip1, sb1.st_size,
262 		    fd2, file2, skip2, sb2.st_size, limit);
263 	}
264 	exit(0);
265 }
266 
267 static void
268 usage(void)
269 {
270 
271 	(void)fprintf(stderr,
272 	    "usage: cmp [-l | -s | -x] [-hz] file1 file2 [skip1 [skip2]]\n");
273 	exit(ERR_EXIT);
274 }
275