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 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 * 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 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