xref: /freebsd/usr.bin/cmp/regular.c (revision 3ff369fed2a08f32dda232c10470b949bef9489f)
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
36 static char sccsid[] = "@(#)regular.c	8.3 (Berkeley) 4/2/94";
37 #endif
38 #endif
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
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 
56 static u_char *remmap(u_char *, int, off_t);
57 #define MMAP_CHUNK (8*1024*1024)
58 
59 #define ROUNDPAGE(i) ((i) & ~pagemask)
60 
61 void
62 c_regular(fd1, file1, skip1, len1, fd2, file2, skip2, len2)
63 	int fd1, fd2;
64 	const char *file1, *file2;
65 	off_t skip1, len1, skip2, len2;
66 {
67 	u_char ch, *p1, *p2, *m1, *m2, *e1, *e2;
68 	off_t byte, length, line;
69 	int dfound;
70 	off_t pagemask, off1, off2;
71 	size_t pagesize;
72 
73 	if (skip1 > len1)
74 		eofmsg(file1);
75 	len1 -= skip1;
76 	if (skip2 > len2)
77 		eofmsg(file2);
78 	len2 -= skip2;
79 
80 	if (sflag && len1 != len2)
81 		exit(DIFF_EXIT);
82 
83 	pagesize = getpagesize();
84 	pagemask = (off_t)pagesize - 1;
85 	off1 = ROUNDPAGE(skip1);
86 	off2 = ROUNDPAGE(skip2);
87 
88 	length = MIN(len1, len2);
89 
90 	if ((m1 = remmap(NULL, fd1, off1)) == NULL) {
91 		c_special(fd1, file1, skip1, fd2, file2, skip2);
92 		return;
93 	}
94 
95 	if ((m2 = remmap(NULL, fd2, off2)) == NULL) {
96 		munmap(m1, MMAP_CHUNK);
97 		c_special(fd1, file1, skip1, fd2, file2, skip2);
98 		return;
99 	}
100 
101 	dfound = 0;
102 	e1 = m1 + MMAP_CHUNK;
103 	e2 = m2 + MMAP_CHUNK;
104 	p1 = m1 + (skip1 - off1);
105 	p2 = m2 + (skip2 - off2);
106 
107 	for (byte = line = 1; length--; ++byte) {
108 		if ((ch = *p1) != *p2) {
109 			if (xflag) {
110 				dfound = 1;
111 				(void)printf("%08llx %02x %02x\n",
112 				    (long long)byte - 1, ch, *p2);
113 			} else if (lflag) {
114 				dfound = 1;
115 				(void)printf("%6lld %3o %3o\n",
116 				    (long long)byte, ch, *p2);
117 			} else
118 				diffmsg(file1, file2, byte, line);
119 				/* NOTREACHED */
120 		}
121 		if (ch == '\n')
122 			++line;
123 		if (++p1 == e1) {
124 			off1 += MMAP_CHUNK;
125 			if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) {
126 				munmap(m2, MMAP_CHUNK);
127 				err(ERR_EXIT, "remmap %s", file1);
128 			}
129 			e1 = m1 + MMAP_CHUNK;
130 		}
131 		if (++p2 == e2) {
132 			off2 += MMAP_CHUNK;
133 			if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) {
134 				munmap(m1, MMAP_CHUNK);
135 				err(ERR_EXIT, "remmap %s", file2);
136 			}
137 			e2 = m2 + MMAP_CHUNK;
138 		}
139 	}
140 	munmap(m1, MMAP_CHUNK);
141 	munmap(m2, MMAP_CHUNK);
142 
143 	if (len1 != len2)
144 		eofmsg (len1 > len2 ? file2 : file1);
145 	if (dfound)
146 		exit(DIFF_EXIT);
147 }
148 
149 static u_char *
150 remmap(mem, fd, offset)
151 	u_char  *mem;
152 	int     fd;
153 	off_t   offset;
154 {
155 	if (mem != NULL)
156 		munmap(mem, MMAP_CHUNK);
157 	mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset);
158 	if (mem == MAP_FAILED)
159 		return (NULL);
160 	madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL);
161 	return (mem);
162 }
163