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 <err.h> 46 #include <limits.h> 47 #include <signal.h> 48 #include <stdlib.h> 49 #include <stdio.h> 50 #include <unistd.h> 51 52 #include "extern.h" 53 54 static u_char *remmap(u_char *, int, off_t); 55 static void segv_handler(int); 56 #define MMAP_CHUNK (8*1024*1024) 57 58 #define ROUNDPAGE(i) ((i) & ~pagemask) 59 60 void 61 c_regular(int fd1, const char *file1, off_t skip1, off_t len1, 62 int fd2, const char *file2, off_t skip2, off_t len2) 63 { 64 u_char ch, *p1, *p2, *m1, *m2, *e1, *e2; 65 off_t byte, length, line; 66 int dfound; 67 off_t pagemask, off1, off2; 68 size_t pagesize; 69 struct sigaction act, oact; 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 sigemptyset(&act.sa_mask); 82 act.sa_flags = SA_NODEFER; 83 act.sa_handler = segv_handler; 84 if (sigaction(SIGSEGV, &act, &oact)) 85 err(ERR_EXIT, "sigaction()"); 86 87 pagesize = getpagesize(); 88 pagemask = (off_t)pagesize - 1; 89 off1 = ROUNDPAGE(skip1); 90 off2 = ROUNDPAGE(skip2); 91 92 length = MIN(len1, len2); 93 94 if ((m1 = remmap(NULL, fd1, off1)) == NULL) { 95 c_special(fd1, file1, skip1, fd2, file2, skip2); 96 return; 97 } 98 99 if ((m2 = remmap(NULL, fd2, off2)) == NULL) { 100 munmap(m1, MMAP_CHUNK); 101 c_special(fd1, file1, skip1, fd2, file2, skip2); 102 return; 103 } 104 105 dfound = 0; 106 e1 = m1 + MMAP_CHUNK; 107 e2 = m2 + MMAP_CHUNK; 108 p1 = m1 + (skip1 - off1); 109 p2 = m2 + (skip2 - off2); 110 111 for (byte = line = 1; length--; ++byte) { 112 if ((ch = *p1) != *p2) { 113 if (xflag) { 114 dfound = 1; 115 (void)printf("%08llx %02x %02x\n", 116 (long long)byte - 1, ch, *p2); 117 } else if (lflag) { 118 dfound = 1; 119 (void)printf("%6lld %3o %3o\n", 120 (long long)byte, ch, *p2); 121 } else 122 diffmsg(file1, file2, byte, line); 123 /* NOTREACHED */ 124 } 125 if (ch == '\n') 126 ++line; 127 if (++p1 == e1) { 128 off1 += MMAP_CHUNK; 129 if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) { 130 munmap(m2, MMAP_CHUNK); 131 err(ERR_EXIT, "remmap %s", file1); 132 } 133 e1 = m1 + MMAP_CHUNK; 134 } 135 if (++p2 == e2) { 136 off2 += MMAP_CHUNK; 137 if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) { 138 munmap(m1, MMAP_CHUNK); 139 err(ERR_EXIT, "remmap %s", file2); 140 } 141 e2 = m2 + MMAP_CHUNK; 142 } 143 } 144 munmap(m1, MMAP_CHUNK); 145 munmap(m2, MMAP_CHUNK); 146 147 if (sigaction(SIGSEGV, &oact, NULL)) 148 err(ERR_EXIT, "sigaction()"); 149 150 if (len1 != len2) 151 eofmsg (len1 > len2 ? file2 : file1); 152 if (dfound) 153 exit(DIFF_EXIT); 154 } 155 156 static u_char * 157 remmap(u_char *mem, int fd, off_t offset) 158 { 159 if (mem != NULL) 160 munmap(mem, MMAP_CHUNK); 161 mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset); 162 if (mem == MAP_FAILED) 163 return (NULL); 164 madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL); 165 return (mem); 166 } 167 168 static void 169 segv_handler(int sig __unused) { 170 static const char msg[] = "cmp: Input/output error (caught SIGSEGV)\n"; 171 172 write(STDERR_FILENO, msg, sizeof(msg)); 173 _exit(EXIT_FAILURE); 174 } 175