xref: /freebsd/usr.bin/cmp/cmp.c (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1)
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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 static const char copyright[] =
36 "@(#) Copyright (c) 1987, 1990, 1993, 1994\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif
39 
40 #if 0
41 #ifndef lint
42 static char sccsid[] = "@(#)cmp.c	8.3 (Berkeley) 4/2/94";
43 #endif
44 #endif
45 
46 #include <sys/cdefs.h>
47 __FBSDID("$FreeBSD$");
48 
49 #include <sys/types.h>
50 #include <sys/stat.h>
51 
52 #include <err.h>
53 #include <errno.h>
54 #include <fcntl.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59 
60 #include "extern.h"
61 
62 int	lflag, sflag, xflag, zflag;
63 
64 static void usage(void);
65 
66 int
67 main(int argc, char *argv[])
68 {
69 	struct stat sb1, sb2;
70 	off_t skip1, skip2;
71 	int ch, fd1, fd2, oflag, special;
72 	const char *file1, *file2;
73 
74 	oflag = O_RDONLY;
75 	while ((ch = getopt(argc, argv, "hlsxz")) != -1)
76 		switch (ch) {
77 		case 'h':		/* Don't follow symlinks */
78 			oflag |= O_NOFOLLOW;
79 			break;
80 		case 'l':		/* print all differences */
81 			lflag = 1;
82 			break;
83 		case 's':		/* silent run */
84 			sflag = 1;
85 			zflag = 1;
86 			break;
87 		case 'x':		/* hex output */
88 			lflag = 1;
89 			xflag = 1;
90 			break;
91 		case 'z':		/* compare size first */
92 			zflag = 1;
93 			break;
94 		case '?':
95 		default:
96 			usage();
97 		}
98 	argv += optind;
99 	argc -= optind;
100 
101 	if (lflag && sflag)
102 		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
103 
104 	if (argc < 2 || argc > 4)
105 		usage();
106 
107 	/* Backward compatibility -- handle "-" meaning stdin. */
108 	special = 0;
109 	if (strcmp(file1 = argv[0], "-") == 0) {
110 		special = 1;
111 		fd1 = 0;
112 		file1 = "stdin";
113 	}
114 	else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
115 		if (!sflag)
116 			err(ERR_EXIT, "%s", file1);
117 		else
118 			exit(ERR_EXIT);
119 	}
120 	if (strcmp(file2 = argv[1], "-") == 0) {
121 		if (special)
122 			errx(ERR_EXIT,
123 				"standard input may only be specified once");
124 		special = 1;
125 		fd2 = 0;
126 		file2 = "stdin";
127 	}
128 	else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
129 		if (!sflag)
130 			err(ERR_EXIT, "%s", file2);
131 		else
132 			exit(ERR_EXIT);
133 	}
134 
135 	skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
136 	skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
137 
138 	if (fd1 == -1) {
139 		if (fd2 == -1) {
140 			c_link(file1, skip1, file2, skip2);
141 			exit(0);
142 		} else if (!sflag)
143 			errx(ERR_EXIT, "%s: Not a symbolic link", file2);
144 		else
145 			exit(ERR_EXIT);
146 	} else if (fd2 == -1) {
147 		if (!sflag)
148 			errx(ERR_EXIT, "%s: Not a symbolic link", file1);
149 		else
150 			exit(ERR_EXIT);
151 	}
152 
153 	if (!special) {
154 		if (fstat(fd1, &sb1)) {
155 			if (!sflag)
156 				err(ERR_EXIT, "%s", file1);
157 			else
158 				exit(ERR_EXIT);
159 		}
160 		if (!S_ISREG(sb1.st_mode))
161 			special = 1;
162 		else {
163 			if (fstat(fd2, &sb2)) {
164 				if (!sflag)
165 					err(ERR_EXIT, "%s", file2);
166 				else
167 					exit(ERR_EXIT);
168 			}
169 			if (!S_ISREG(sb2.st_mode))
170 				special = 1;
171 		}
172 	}
173 
174 	if (special)
175 		c_special(fd1, file1, skip1, fd2, file2, skip2);
176 	else {
177 		if (zflag && sb1.st_size != sb2.st_size) {
178 			if (!sflag)
179 				(void) printf("%s %s differ: size\n",
180 				    file1, file2);
181 			exit(DIFF_EXIT);
182 		}
183 		c_regular(fd1, file1, skip1, sb1.st_size,
184 		    fd2, file2, skip2, sb2.st_size);
185 	}
186 	exit(0);
187 }
188 
189 static void
190 usage(void)
191 {
192 
193 	(void)fprintf(stderr,
194 	    "usage: cmp [-l | -s | -x] [-hz] file1 file2 [skip1 [skip2]]\n");
195 	exit(ERR_EXIT);
196 }
197