regular.c revision 100815 
1/*-
2 * Copyright (c) 1991, 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#if 0
35#ifndef lint
36static char sccsid[] = "@(#)regular.c	8.3 (Berkeley) 4/2/94";
37#endif
38#endif
39
40#include <sys/cdefs.h>
41__FBSDID("$FreeBSD: head/usr.bin/cmp/regular.c 100815 2002-07-28 15:13:17Z dwmalone $");
42
43#include <sys/param.h>
44#include <sys/mman.h>
45#include <sys/stat.h>
46
47#include <err.h>
48#include <limits.h>
49#include <stdlib.h>
50#include <stdio.h>
51#include <string.h>
52#include <unistd.h>
53
54#include "extern.h"
55
56static u_char *remmap(u_char *, int, off_t);
57#define MMAP_CHUNK (8*1024*1024)
58
59#define ROUNDPAGE(i) ((i) & ~pagemask)
60
61void
62c_regular(int fd1, const char *file1, off_t skip1, off_t len1,
63    int fd2, const char *file2, off_t skip2, off_t len2)
64{
65	u_char ch, *p1, *p2, *m1, *m2, *e1, *e2;
66	off_t byte, length, line;
67	int dfound;
68	off_t pagemask, off1, off2;
69	size_t pagesize;
70
71	if (skip1 > len1)
72		eofmsg(file1);
73	len1 -= skip1;
74	if (skip2 > len2)
75		eofmsg(file2);
76	len2 -= skip2;
77
78	if (sflag && len1 != len2)
79		exit(DIFF_EXIT);
80
81	pagesize = getpagesize();
82	pagemask = (off_t)pagesize - 1;
83	off1 = ROUNDPAGE(skip1);
84	off2 = ROUNDPAGE(skip2);
85
86	length = MIN(len1, len2);
87
88	if ((m1 = remmap(NULL, fd1, off1)) == NULL) {
89		c_special(fd1, file1, skip1, fd2, file2, skip2);
90		return;
91	}
92
93	if ((m2 = remmap(NULL, fd2, off2)) == NULL) {
94		munmap(m1, MMAP_CHUNK);
95		c_special(fd1, file1, skip1, fd2, file2, skip2);
96		return;
97	}
98
99	dfound = 0;
100	e1 = m1 + MMAP_CHUNK;
101	e2 = m2 + MMAP_CHUNK;
102	p1 = m1 + (skip1 - off1);
103	p2 = m2 + (skip2 - off2);
104
105	for (byte = line = 1; length--; ++byte) {
106		if ((ch = *p1) != *p2) {
107			if (xflag) {
108				dfound = 1;
109				(void)printf("%08llx %02x %02x\n",
110				    (long long)byte - 1, ch, *p2);
111			} else if (lflag) {
112				dfound = 1;
113				(void)printf("%6lld %3o %3o\n",
114				    (long long)byte, ch, *p2);
115			} else
116				diffmsg(file1, file2, byte, line);
117				/* NOTREACHED */
118		}
119		if (ch == '\n')
120			++line;
121		if (++p1 == e1) {
122			off1 += MMAP_CHUNK;
123			if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) {
124				munmap(m2, MMAP_CHUNK);
125				err(ERR_EXIT, "remmap %s", file1);
126			}
127			e1 = m1 + MMAP_CHUNK;
128		}
129		if (++p2 == e2) {
130			off2 += MMAP_CHUNK;
131			if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) {
132				munmap(m1, MMAP_CHUNK);
133				err(ERR_EXIT, "remmap %s", file2);
134			}
135			e2 = m2 + MMAP_CHUNK;
136		}
137	}
138	munmap(m1, MMAP_CHUNK);
139	munmap(m2, MMAP_CHUNK);
140
141	if (len1 != len2)
142		eofmsg (len1 > len2 ? file2 : file1);
143	if (dfound)
144		exit(DIFF_EXIT);
145}
146
147static u_char *
148remmap(u_char *mem, int fd, off_t offset)
149{
150	if (mem != NULL)
151		munmap(mem, MMAP_CHUNK);
152	mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset);
153	if (mem == MAP_FAILED)
154		return (NULL);
155	madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL);
156	return (mem);
157}
158