xref: /dragonfly/usr.bin/cmp/cmp.c (revision 6ca88057)
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. 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  * $FreeBSD: head/usr.bin/cmp/cmp.c 216370 2010-12-11 08:32:16Z joel $
30  *
31  * @(#) Copyright (c) 1987, 1990, 1993, 1994 The Regents of the University of California.  All rights reserved.
32  * @(#)cmp.c	8.3 (Berkeley) 4/2/94
33  */
34 
35 #include <sys/types.h>
36 #include <sys/stat.h>
37 
38 #include <err.h>
39 #include <errno.h>
40 #include <fcntl.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <unistd.h>
45 
46 #include "extern.h"
47 
48 int	lflag, sflag, xflag, zflag;
49 
50 static void usage (void);
51 
52 int
53 main(int argc, char **argv)
54 {
55 	struct stat sb1, sb2;
56 	off_t skip1, skip2;
57 	int ch, fd1, fd2, oflag, special;
58 	const char *file1, *file2;
59 
60 	oflag = O_RDONLY;
61 	while ((ch = getopt(argc, argv, "hlsxz")) != -1)
62 		switch (ch) {
63 		case 'h':		/* Don't follow symlinks */
64 			oflag |= O_NOFOLLOW;
65 			break;
66 		case 'l':		/* print all differences */
67 			lflag = 1;
68 			break;
69 		case 's':		/* silent run */
70 			sflag = 1;
71 			zflag = 1;
72 			break;
73 		case 'x':		/* hex output */
74 			lflag = 1;
75 			xflag = 1;
76 			break;
77 		case 'z':		/* compare size first */
78 			zflag = 1;
79 			break;
80 		case '?':
81 		default:
82 			usage();
83 		}
84 	argv += optind;
85 	argc -= optind;
86 
87 	if (lflag && sflag)
88 		errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
89 
90 	if (argc < 2 || argc > 4)
91 		usage();
92 
93 	/* Backward compatibility -- handle "-" meaning stdin. */
94 	special = 0;
95 	if (strcmp(file1 = argv[0], "-") == 0) {
96 		special = 1;
97 		fd1 = 0;
98 		file1 = "stdin";
99 	}
100 	else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
101 		if (!sflag)
102 			err(ERR_EXIT, "%s", file1);
103 		else
104 			exit(ERR_EXIT);
105 	}
106 	if (strcmp(file2 = argv[1], "-") == 0) {
107 		if (special)
108 			errx(ERR_EXIT,
109 				"standard input may only be specified once");
110 		special = 1;
111 		fd2 = 0;
112 		file2 = "stdin";
113 	}
114 	else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
115 		if (!sflag)
116 			err(ERR_EXIT, "%s", file2);
117 		else
118 			exit(ERR_EXIT);
119 	}
120 
121 	skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
122 	skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
123 
124 	if (fd1 == -1) {
125 		if (fd2 == -1) {
126 			c_link(file1, skip1, file2, skip2);
127 			exit(0);
128 		} else if (!sflag)
129 			errx(ERR_EXIT, "%s: Not a symbolic link", file2);
130 		else
131 			exit(ERR_EXIT);
132 	} else if (fd2 == -1) {
133 		if (!sflag)
134 			errx(ERR_EXIT, "%s: Not a symbolic link", file1);
135 		else
136 			exit(ERR_EXIT);
137 	}
138 
139 	if (!special) {
140 		if (fstat(fd1, &sb1)) {
141 			if (!sflag)
142 				err(ERR_EXIT, "%s", file1);
143 			else
144 				exit(ERR_EXIT);
145 		}
146 		if (!S_ISREG(sb1.st_mode))
147 			special = 1;
148 		else {
149 			if (fstat(fd2, &sb2)) {
150 				if (!sflag)
151 					err(ERR_EXIT, "%s", file2);
152 				else
153 					exit(ERR_EXIT);
154 			}
155 			if (!S_ISREG(sb2.st_mode))
156 				special = 1;
157 		}
158 	}
159 
160 	if (special)
161 		c_special(fd1, file1, skip1, fd2, file2, skip2);
162 	else {
163 		if (zflag && sb1.st_size != sb2.st_size) {
164 			if (!sflag)
165 				(void) printf("%s %s differ: size\n",
166 				    file1, file2);
167 			exit(DIFF_EXIT);
168 		}
169 		c_regular(fd1, file1, skip1, sb1.st_size,
170 		    fd2, file2, skip2, sb2.st_size);
171 	}
172 	exit(0);
173 }
174 
175 static void
176 usage(void)
177 {
178 
179 	(void)fprintf(stderr,
180 	    "usage: cmp [-l | -s | -x] [-hz] file1 file2 [skip1 [skip2]]\n");
181 	exit(ERR_EXIT);
182 }
183