1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2005 Brian Somers <brian@FreeBSD.org>
5 * 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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/types.h>
30#include <err.h>
31#include <limits.h>
32#include <stdbool.h>
33#include <stdio.h>
34#include <stdlib.h>
35#include <unistd.h>
36
37#include "extern.h"
38
39void
40c_link(const char *file1, off_t skip1, const char *file2, off_t skip2,
41    off_t limit)
42{
43	char buf1[PATH_MAX], *p1;
44	char buf2[PATH_MAX], *p2;
45	int dfound, len1, len2;
46	off_t byte;
47	u_char ch;
48
49	if ((len1 = readlink(file1, buf1, sizeof(buf1) - 1)) < 0) {
50		if (!sflag)
51			err(ERR_EXIT, "%s", file1);
52		else
53			exit(ERR_EXIT);
54	}
55
56	if ((len2 = readlink(file2, buf2, sizeof(buf2) - 1)) < 0) {
57		if (!sflag)
58			err(ERR_EXIT, "%s", file2);
59		else
60			exit(ERR_EXIT);
61	}
62
63	if (skip1 > len1)
64		skip1 = len1;
65	buf1[len1] = '\0';
66
67	if (skip2 > len2)
68		skip2 = len2;
69	buf2[len2] = '\0';
70
71	dfound = 0;
72	byte = 1;
73	for (p1 = buf1 + skip1, p2 = buf2 + skip2;
74	    *p1 && *p2 && (limit == 0 || byte <= limit); p1++, p2++) {
75		if ((ch = *p1) != *p2) {
76			if (xflag) {
77				dfound = 1;
78				(void)printf("%08llx %02x %02x\n",
79				    (long long)byte - 1, ch, *p2);
80			} else if (lflag) {
81				dfound = 1;
82				if (bflag)
83					(void)printf("%6lld %3o %c %3o %c\n",
84					    (long long)byte, ch, ch, *p2, *p2);
85				else
86					(void)printf("%6lld %3o %3o\n",
87					    (long long)byte, ch, *p2);
88			} else
89				diffmsg(file1, file2, byte, 1, ch, *p2);
90				/* NOTREACHED */
91		}
92		byte++;
93	}
94
95	if (*p1 || *p2)
96		eofmsg (*p1 ? file2 : file1);
97	if (dfound)
98		exit(DIFF_EXIT);
99}
100