xref: /freebsd/usr.bin/cmp/cmp.c (revision 586f63035fbe5e45cfc971037fd76375661ece26)
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  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #ifndef lint
31 static const char copyright[] =
32 "@(#) Copyright (c) 1987, 1990, 1993, 1994\n\
33 	The Regents of the University of California.  All rights reserved.\n";
34 #endif
35 
36 #if 0
37 #ifndef lint
38 static char sccsid[] = "@(#)cmp.c	8.3 (Berkeley) 4/2/94";
39 #endif
40 #endif
41 
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
44 
45 #include <sys/types.h>
46 #include <sys/stat.h>
47 
48 #include <err.h>
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <unistd.h>
55 
56 #include "extern.h"
57 
58 int	lflag, sflag, xflag, zflag;
59 
60 static void usage(void);
61 
62 int
63 main(int argc, char *argv[])
64 {
65 	struct stat sb1, sb2;
66 	off_t skip1, skip2;
67 	int ch, fd1, fd2, oflag, special;
68 	const char *file1, *file2;
69 
70 	oflag = O_RDONLY;
71 	while ((ch = getopt(argc, argv, "hlsxz")) != -1)
72 		switch (ch) {
73 		case 'h':		/* Don't follow symlinks */
74 			oflag |= O_NOFOLLOW;
75 			break;
76 		case 'l':		/* print all differences */
77 			lflag = 1;
78 			break;
79 		case 's':		/* silent run */
80 			sflag = 1;
81 			zflag = 1;
82 			break;
83 		case 'x':		/* hex output */
84 			lflag = 1;
85 			xflag = 1;
86 			break;
87 		case 'z':		/* compare size first */
88 			zflag = 1;
89 			break;
90 		case '?':
91 		default:
92 			usage();
93 		}
94 	argv += optind;
95 	argc -= optind;
96 
97 	if (lflag && sflag)
98 		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
99 
100 	if (argc < 2 || argc > 4)
101 		usage();
102 
103 	/* Backward compatibility -- handle "-" meaning stdin. */
104 	special = 0;
105 	if (strcmp(file1 = argv[0], "-") == 0) {
106 		special = 1;
107 		fd1 = 0;
108 		file1 = "stdin";
109 	}
110 	else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
111 		if (!sflag)
112 			err(ERR_EXIT, "%s", file1);
113 		else
114 			exit(ERR_EXIT);
115 	}
116 	if (strcmp(file2 = argv[1], "-") == 0) {
117 		if (special)
118 			errx(ERR_EXIT,
119 				"standard input may only be specified once");
120 		special = 1;
121 		fd2 = 0;
122 		file2 = "stdin";
123 	}
124 	else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
125 		if (!sflag)
126 			err(ERR_EXIT, "%s", file2);
127 		else
128 			exit(ERR_EXIT);
129 	}
130 
131 	skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
132 	skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
133 
134 	if (fd1 == -1) {
135 		if (fd2 == -1) {
136 			c_link(file1, skip1, file2, skip2);
137 			exit(0);
138 		} else if (!sflag)
139 			errx(ERR_EXIT, "%s: Not a symbolic link", file2);
140 		else
141 			exit(ERR_EXIT);
142 	} else if (fd2 == -1) {
143 		if (!sflag)
144 			errx(ERR_EXIT, "%s: Not a symbolic link", file1);
145 		else
146 			exit(ERR_EXIT);
147 	}
148 
149 	if (!special) {
150 		if (fstat(fd1, &sb1)) {
151 			if (!sflag)
152 				err(ERR_EXIT, "%s", file1);
153 			else
154 				exit(ERR_EXIT);
155 		}
156 		if (!S_ISREG(sb1.st_mode))
157 			special = 1;
158 		else {
159 			if (fstat(fd2, &sb2)) {
160 				if (!sflag)
161 					err(ERR_EXIT, "%s", file2);
162 				else
163 					exit(ERR_EXIT);
164 			}
165 			if (!S_ISREG(sb2.st_mode))
166 				special = 1;
167 		}
168 	}
169 
170 	if (special)
171 		c_special(fd1, file1, skip1, fd2, file2, skip2);
172 	else {
173 		if (zflag && sb1.st_size != sb2.st_size) {
174 			if (!sflag)
175 				(void) printf("%s %s differ: size\n",
176 				    file1, file2);
177 			exit(DIFF_EXIT);
178 		}
179 		c_regular(fd1, file1, skip1, sb1.st_size,
180 		    fd2, file2, skip2, sb2.st_size);
181 	}
182 	exit(0);
183 }
184 
185 static void
186 usage(void)
187 {
188 
189 	(void)fprintf(stderr,
190 	    "usage: cmp [-l | -s | -x] [-hz] file1 file2 [skip1 [skip2]]\n");
191 	exit(ERR_EXIT);
192 }
193