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
32 #if 0
33 #ifndef lint
34 static char sccsid[] = "@(#)regular.c 8.3 (Berkeley) 4/2/94";
35 #endif
36 #endif
37
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40
41 #include <sys/param.h>
42 #include <sys/mman.h>
43 #include <sys/stat.h>
44
45 #include <capsicum_helpers.h>
46 #include <err.h>
47 #include <limits.h>
48 #include <signal.h>
49 #include <stdlib.h>
50 #include <stdio.h>
51 #include <unistd.h>
52
53 #include "extern.h"
54
55 static u_char *remmap(u_char *, int, off_t);
56 static void segv_handler(int);
57 #define MMAP_CHUNK (8*1024*1024)
58
59 #define ROUNDPAGE(i) ((i) & ~pagemask)
60
61 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,off_t limit)62 c_regular(int fd1, const char *file1, off_t skip1, off_t len1,
63 int fd2, const char *file2, off_t skip2, off_t len2, off_t limit)
64 {
65 struct sigaction act, oact;
66 cap_rights_t rights;
67 u_char ch, *p1, *p2, *m1, *m2, *e1, *e2;
68 off_t byte, length, line;
69 off_t pagemask, off1, off2;
70 size_t pagesize;
71 int dfound;
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 if (limit > 0)
90 length = MIN(length, limit);
91
92 if ((m1 = remmap(NULL, fd1, off1)) == NULL) {
93 c_special(fd1, file1, skip1, fd2, file2, skip2, limit);
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, limit);
100 return;
101 }
102
103 if (caph_rights_limit(fd1, cap_rights_init(&rights, CAP_MMAP_R)) < 0)
104 err(1, "unable to limit rights for %s", file1);
105 if (caph_rights_limit(fd2, cap_rights_init(&rights, CAP_MMAP_R)) < 0)
106 err(1, "unable to limit rights for %s", file2);
107 if (caph_enter() < 0)
108 err(ERR_EXIT, "unable to enter capability mode");
109
110 sigemptyset(&act.sa_mask);
111 act.sa_flags = SA_NODEFER;
112 act.sa_handler = segv_handler;
113 if (sigaction(SIGSEGV, &act, &oact))
114 err(ERR_EXIT, "sigaction()");
115
116 dfound = 0;
117 e1 = m1 + MMAP_CHUNK;
118 e2 = m2 + MMAP_CHUNK;
119 p1 = m1 + (skip1 - off1);
120 p2 = m2 + (skip2 - off2);
121
122 for (byte = line = 1; length--; ++byte) {
123 if ((ch = *p1) != *p2) {
124 if (xflag) {
125 dfound = 1;
126 (void)printf("%08llx %02x %02x\n",
127 (long long)byte - 1, ch, *p2);
128 } else if (lflag) {
129 dfound = 1;
130 if (bflag)
131 (void)printf("%6lld %3o %c %3o %c\n",
132 (long long)byte, ch, ch, *p2, *p2);
133 else
134 (void)printf("%6lld %3o %3o\n",
135 (long long)byte, ch, *p2);
136 } else
137 diffmsg(file1, file2, byte, line, ch, *p2);
138 /* NOTREACHED */
139 }
140 if (ch == '\n')
141 ++line;
142 if (++p1 == e1) {
143 off1 += MMAP_CHUNK;
144 if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) {
145 munmap(m2, MMAP_CHUNK);
146 err(ERR_EXIT, "remmap %s", file1);
147 }
148 e1 = m1 + MMAP_CHUNK;
149 }
150 if (++p2 == e2) {
151 off2 += MMAP_CHUNK;
152 if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) {
153 munmap(m1, MMAP_CHUNK);
154 err(ERR_EXIT, "remmap %s", file2);
155 }
156 e2 = m2 + MMAP_CHUNK;
157 }
158 }
159 munmap(m1, MMAP_CHUNK);
160 munmap(m2, MMAP_CHUNK);
161
162 if (sigaction(SIGSEGV, &oact, NULL))
163 err(ERR_EXIT, "sigaction()");
164
165 if (len1 != len2)
166 eofmsg (len1 > len2 ? file2 : file1);
167 if (dfound)
168 exit(DIFF_EXIT);
169 }
170
171 static u_char *
remmap(u_char * mem,int fd,off_t offset)172 remmap(u_char *mem, int fd, off_t offset)
173 {
174 if (mem != NULL)
175 munmap(mem, MMAP_CHUNK);
176 mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset);
177 if (mem == MAP_FAILED)
178 return (NULL);
179 madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL);
180 return (mem);
181 }
182
183 static void
segv_handler(int sig __unused)184 segv_handler(int sig __unused) {
185 static const char msg[] = "cmp: Input/output error (caught SIGSEGV)\n";
186
187 write(STDERR_FILENO, msg, sizeof(msg));
188 _exit(EXIT_FAILURE);
189 }
190