xref: /freebsd/usr.bin/cmp/link.c (revision 41059135ce931c0f1014a999ffabc6bc470ce856)
1 /*-
2  * Copyright (c) 2005 Brian Somers <brian@FreeBSD.org>
3  * 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  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/types.h>
31 #include <err.h>
32 #include <limits.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <unistd.h>
36 
37 #include "extern.h"
38 
39 void
40 c_link(const char *file1, off_t skip1, const char *file2, off_t skip2)
41 {
42 	char buf1[PATH_MAX], *p1;
43 	char buf2[PATH_MAX], *p2;
44 	int dfound, len1, len2;
45 	off_t byte;
46 	u_char ch;
47 
48 	if ((len1 = readlink(file1, buf1, sizeof(buf1) - 1)) < 0) {
49 		if (!sflag)
50 			err(ERR_EXIT, "%s", file1);
51 		else
52 			exit(ERR_EXIT);
53 	}
54 
55 	if ((len2 = readlink(file2, buf2, sizeof(buf2) - 1)) < 0) {
56 		if (!sflag)
57 			err(ERR_EXIT, "%s", file2);
58 		else
59 			exit(ERR_EXIT);
60 	}
61 
62 	if (skip1 > len1)
63 		skip1 = len1;
64 	buf1[len1] = '\0';
65 
66 	if (skip2 > len2)
67 		skip2 = len2;
68 	buf2[len2] = '\0';
69 
70 	dfound = 0;
71 	byte = 1;
72 	for (p1 = buf1 + skip1, p2 = buf2 + skip2; *p1 && *p2; p1++, p2++) {
73 		if ((ch = *p1) != *p2) {
74 			if (xflag) {
75 				dfound = 1;
76 				(void)printf("%08llx %02x %02x\n",
77 				    (long long)byte - 1, ch, *p2);
78 			} else if (lflag) {
79 				dfound = 1;
80 				(void)printf("%6lld %3o %3o\n",
81 				    (long long)byte, ch, *p2);
82 			} else
83 				diffmsg(file1, file2, byte, 1);
84 				/* NOTREACHED */
85 		}
86 		byte++;
87 	}
88 
89 	if (*p1 || *p2)
90 		eofmsg (*p1 ? file2 : file1);
91 	if (dfound)
92 		exit(DIFF_EXIT);
93 }
94