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 * 3. 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 * $FreeBSD: head/usr.bin/cmp/regular.c 223376 2011-06-21 20:44:06Z delphij $ 30 * 31 * @(#)regular.c 8.3 (Berkeley) 4/2/94 32 */ 33 34 #include <sys/param.h> 35 #include <sys/mman.h> 36 #include <sys/stat.h> 37 38 #include <err.h> 39 #include <limits.h> 40 #include <signal.h> 41 #include <stdlib.h> 42 #include <stdint.h> 43 #include <stdio.h> 44 #include <unistd.h> 45 46 #include "extern.h" 47 48 static u_char *remmap(u_char *, int, off_t); 49 static void segv_handler(int); 50 #define MMAP_CHUNK (8*1024*1024) 51 52 #define ROUNDPAGE(i) ((i) & ~pagemask) 53 54 void 55 c_regular(int fd1, const char *file1, off_t skip1, off_t len1, 56 int fd2, const char *file2, off_t skip2, off_t len2) 57 { 58 u_char ch, *p1, *p2, *m1, *m2, *e1, *e2; 59 off_t byte, length, line; 60 int dfound; 61 off_t pagemask, off1, off2; 62 size_t pagesize; 63 struct sigaction act, oact; 64 65 if (skip1 > len1) 66 eofmsg(file1); 67 len1 -= skip1; 68 if (skip2 > len2) 69 eofmsg(file2); 70 len2 -= skip2; 71 72 if (sflag && len1 != len2) 73 exit(DIFF_EXIT); 74 75 sigemptyset(&act.sa_mask); 76 act.sa_flags = SA_NODEFER; 77 act.sa_handler = segv_handler; 78 if (sigaction(SIGSEGV, &act, &oact)) 79 err(ERR_EXIT, "sigaction()"); 80 81 pagesize = getpagesize(); 82 pagemask = (off_t)pagesize - 1; 83 off1 = ROUNDPAGE(skip1); 84 off2 = ROUNDPAGE(skip2); 85 86 length = MIN(len1, len2); 87 88 if ((m1 = remmap(NULL, fd1, off1)) == NULL) { 89 c_special(fd1, file1, skip1, fd2, file2, skip2); 90 return; 91 } 92 93 if ((m2 = remmap(NULL, fd2, off2)) == NULL) { 94 munmap(m1, MMAP_CHUNK); 95 c_special(fd1, file1, skip1, fd2, file2, skip2); 96 return; 97 } 98 99 dfound = 0; 100 e1 = m1 + MMAP_CHUNK; 101 e2 = m2 + MMAP_CHUNK; 102 p1 = m1 + (skip1 - off1); 103 p2 = m2 + (skip2 - off2); 104 105 for (byte = line = 1; length--; ++byte) { 106 if ((ch = *p1) != *p2) { 107 if (xflag) { 108 dfound = 1; 109 printf("%08jx %02x %02x\n", 110 (intmax_t)byte - 1, ch, *p2); 111 } else if (lflag) { 112 dfound = 1; 113 printf("%6jd %3o %3o\n", 114 (intmax_t)byte, ch, *p2); 115 } else 116 diffmsg(file1, file2, byte, line); 117 /* NOTREACHED */ 118 } 119 if (ch == '\n') 120 ++line; 121 if (++p1 == e1) { 122 off1 += MMAP_CHUNK; 123 if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) { 124 munmap(m2, MMAP_CHUNK); 125 err(ERR_EXIT, "remmap %s", file1); 126 } 127 e1 = m1 + MMAP_CHUNK; 128 } 129 if (++p2 == e2) { 130 off2 += MMAP_CHUNK; 131 if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) { 132 munmap(m1, MMAP_CHUNK); 133 err(ERR_EXIT, "remmap %s", file2); 134 } 135 e2 = m2 + MMAP_CHUNK; 136 } 137 } 138 munmap(m1, MMAP_CHUNK); 139 munmap(m2, MMAP_CHUNK); 140 141 if (sigaction(SIGSEGV, &oact, NULL)) 142 err(ERR_EXIT, "sigaction()"); 143 144 if (len1 != len2) 145 eofmsg (len1 > len2 ? file2 : file1); 146 if (dfound) 147 exit(DIFF_EXIT); 148 } 149 150 static u_char * 151 remmap(u_char *mem, int fd, off_t offset) 152 { 153 if (mem != NULL) 154 munmap(mem, MMAP_CHUNK); 155 mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset); 156 if (mem == MAP_FAILED) 157 return (NULL); 158 madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL); 159 return (mem); 160 } 161 162 static void 163 segv_handler(int sig __unused) { 164 static const char msg[] = "cmp: Input/output error (caught SIGSEGV)\n"; 165 166 write(STDERR_FILENO, msg, sizeof(msg)); 167 _exit(EXIT_FAILURE); 168 } 169