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 * 4. 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
30 #if 0
31 #ifndef lint
32 static char sccsid[] = "@(#)regular.c 8.3 (Berkeley) 4/2/94";
33 #endif
34 #endif
35
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38
39 #include <sys/param.h>
40 #include <sys/mman.h>
41 #include <sys/stat.h>
42
43 #include <err.h>
44 #include <limits.h>
45 #include <signal.h>
46 #include <stdlib.h>
47 #include <stdio.h>
48 #include <unistd.h>
49
50 #include "extern.h"
51
52 static u_char *remmap(u_char *, int, off_t);
53 static void segv_handler(int);
54 #define MMAP_CHUNK (8*1024*1024)
55
56 #define ROUNDPAGE(i) ((i) & ~pagemask)
57
58 void
c_regular(int fd1,const char * file1,off_t skip1,off_t len1,int fd2,const char * file2,off_t skip2,off_t len2)59 c_regular(int fd1, const char *file1, off_t skip1, off_t len1,
60 int fd2, const char *file2, off_t skip2, off_t len2)
61 {
62 u_char ch, *p1, *p2, *m1, *m2, *e1, *e2;
63 off_t byte, length, line;
64 int dfound;
65 off_t pagemask, off1, off2;
66 size_t pagesize;
67 struct sigaction act, oact;
68
69 if (skip1 > len1)
70 eofmsg(file1);
71 len1 -= skip1;
72 if (skip2 > len2)
73 eofmsg(file2);
74 len2 -= skip2;
75
76 if (sflag && len1 != len2)
77 exit(DIFF_EXIT);
78
79 sigemptyset(&act.sa_mask);
80 act.sa_flags = SA_NODEFER;
81 act.sa_handler = segv_handler;
82 if (sigaction(SIGSEGV, &act, &oact))
83 err(ERR_EXIT, "sigaction()");
84
85 pagesize = getpagesize();
86 pagemask = (off_t)pagesize - 1;
87 off1 = ROUNDPAGE(skip1);
88 off2 = ROUNDPAGE(skip2);
89
90 length = MIN(len1, len2);
91
92 if ((m1 = remmap(NULL, fd1, off1)) == NULL) {
93 c_special(fd1, file1, skip1, fd2, file2, skip2);
94 return;
95 }
96
97 if ((m2 = remmap(NULL, fd2, off2)) == NULL) {
98 munmap(m1, MMAP_CHUNK);
99 c_special(fd1, file1, skip1, fd2, file2, skip2);
100 return;
101 }
102
103 dfound = 0;
104 e1 = m1 + MMAP_CHUNK;
105 e2 = m2 + MMAP_CHUNK;
106 p1 = m1 + (skip1 - off1);
107 p2 = m2 + (skip2 - off2);
108
109 for (byte = line = 1; length--; ++byte) {
110 if ((ch = *p1) != *p2) {
111 if (xflag) {
112 dfound = 1;
113 (void)printf("%08llx %02x %02x\n",
114 (long long)byte - 1, ch, *p2);
115 } else if (lflag) {
116 dfound = 1;
117 (void)printf("%6lld %3o %3o\n",
118 (long long)byte, ch, *p2);
119 } else
120 diffmsg(file1, file2, byte, line);
121 /* NOTREACHED */
122 }
123 if (ch == '\n')
124 ++line;
125 if (++p1 == e1) {
126 off1 += MMAP_CHUNK;
127 if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) {
128 munmap(m2, MMAP_CHUNK);
129 err(ERR_EXIT, "remmap %s", file1);
130 }
131 e1 = m1 + MMAP_CHUNK;
132 }
133 if (++p2 == e2) {
134 off2 += MMAP_CHUNK;
135 if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) {
136 munmap(m1, MMAP_CHUNK);
137 err(ERR_EXIT, "remmap %s", file2);
138 }
139 e2 = m2 + MMAP_CHUNK;
140 }
141 }
142 munmap(m1, MMAP_CHUNK);
143 munmap(m2, MMAP_CHUNK);
144
145 if (sigaction(SIGSEGV, &oact, NULL))
146 err(ERR_EXIT, "sigaction()");
147
148 if (len1 != len2)
149 eofmsg (len1 > len2 ? file2 : file1);
150 if (dfound)
151 exit(DIFF_EXIT);
152 }
153
154 static u_char *
remmap(u_char * mem,int fd,off_t offset)155 remmap(u_char *mem, int fd, off_t offset)
156 {
157 if (mem != NULL)
158 munmap(mem, MMAP_CHUNK);
159 mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset);
160 if (mem == MAP_FAILED)
161 return (NULL);
162 madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL);
163 return (mem);
164 }
165
166 static void
segv_handler(int sig __unused)167 segv_handler(int sig __unused) {
168 static const char msg[] = "cmp: Input/output error (caught SIGSEGV)\n";
169
170 write(STDERR_FILENO, msg, sizeof(msg));
171 _exit(EXIT_FAILURE);
172 }
173