1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1991, 1993, 1994
5 * The Regents of the University of California. 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 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * $FreeBSD: head/usr.bin/cmp/regular.c 223376 2011-06-21 20:44:06Z delphij $
32 *
33 * @(#)regular.c 8.3 (Berkeley) 4/2/94
34 */
35
36 #include <sys/param.h>
37 #include <sys/mman.h>
38 #include <sys/stat.h>
39
40 #include <err.h>
41 #include <limits.h>
42 #include <signal.h>
43 #include <stdlib.h>
44 #include <stdio.h>
45 #include <unistd.h>
46
47 #include "extern.h"
48
49 static u_char *remmap(u_char *, int, off_t);
50 static void segv_handler(int);
51 #define MMAP_CHUNK (8*1024*1024)
52
53 #define ROUNDPAGE(i) ((i) & ~pagemask)
54
55 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)56 c_regular(int fd1, const char *file1, off_t skip1, off_t len1,
57 int fd2, const char *file2, off_t skip2, off_t len2)
58 {
59 struct sigaction act, oact;
60 u_char ch, *p1, *p2, *m1, *m2, *e1, *e2;
61 off_t byte, length, line;
62 off_t pagemask, off1, off2;
63 size_t pagesize;
64 int dfound;
65
66 if (skip1 > len1)
67 eofmsg(file1);
68 len1 -= skip1;
69 if (skip2 > len2)
70 eofmsg(file2);
71 len2 -= skip2;
72
73 if (sflag && len1 != len2)
74 exit(DIFF_EXIT);
75
76 pagesize = getpagesize();
77 pagemask = (off_t)pagesize - 1;
78 off1 = ROUNDPAGE(skip1);
79 off2 = ROUNDPAGE(skip2);
80
81 length = MIN(len1, len2);
82
83 if ((m1 = remmap(NULL, fd1, off1)) == NULL) {
84 c_special(fd1, file1, skip1, fd2, file2, skip2);
85 return;
86 }
87
88 if ((m2 = remmap(NULL, fd2, off2)) == NULL) {
89 munmap(m1, MMAP_CHUNK);
90 c_special(fd1, file1, skip1, fd2, file2, skip2);
91 return;
92 }
93
94 sigemptyset(&act.sa_mask);
95 act.sa_flags = SA_NODEFER;
96 act.sa_handler = segv_handler;
97 if (sigaction(SIGSEGV, &act, &oact))
98 err(ERR_EXIT, "sigaction()");
99
100 dfound = 0;
101 e1 = m1 + MMAP_CHUNK;
102 e2 = m2 + MMAP_CHUNK;
103 p1 = m1 + (skip1 - off1);
104 p2 = m2 + (skip2 - off2);
105
106 for (byte = line = 1; length--; ++byte) {
107 if ((ch = *p1) != *p2) {
108 if (xflag) {
109 dfound = 1;
110 printf("%08jx %02x %02x\n",
111 (intmax_t)byte - 1, ch, *p2);
112 } else if (lflag) {
113 dfound = 1;
114 printf("%6jd %3o %3o\n",
115 (intmax_t)byte, ch, *p2);
116 } else
117 diffmsg(file1, file2, byte, line);
118 /* NOTREACHED */
119 }
120 if (ch == '\n')
121 ++line;
122 if (++p1 == e1) {
123 off1 += MMAP_CHUNK;
124 if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) {
125 munmap(m2, MMAP_CHUNK);
126 err(ERR_EXIT, "remmap %s", file1);
127 }
128 e1 = m1 + MMAP_CHUNK;
129 }
130 if (++p2 == e2) {
131 off2 += MMAP_CHUNK;
132 if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) {
133 munmap(m1, MMAP_CHUNK);
134 err(ERR_EXIT, "remmap %s", file2);
135 }
136 e2 = m2 + MMAP_CHUNK;
137 }
138 }
139 munmap(m1, MMAP_CHUNK);
140 munmap(m2, MMAP_CHUNK);
141
142 if (sigaction(SIGSEGV, &oact, NULL))
143 err(ERR_EXIT, "sigaction()");
144
145 if (len1 != len2)
146 eofmsg (len1 > len2 ? file2 : file1);
147 if (dfound)
148 exit(DIFF_EXIT);
149 }
150
151 static u_char *
remmap(u_char * mem,int fd,off_t offset)152 remmap(u_char *mem, int fd, off_t offset)
153 {
154 if (mem != NULL)
155 munmap(mem, MMAP_CHUNK);
156 mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset);
157 if (mem == MAP_FAILED)
158 return (NULL);
159 madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL);
160 return (mem);
161 }
162
163 static void
segv_handler(int sig __unused)164 segv_handler(int sig __unused) {
165 static const char msg[] = "cmp: Input/output error (caught SIGSEGV)\n";
166
167 write(STDERR_FILENO, msg, sizeof(msg));
168 _exit(EXIT_FAILURE);
169 }
170