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 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 (void)printf("%6lld %3o %3o\n", 131 (long long)byte, ch, *p2); 132 } else 133 diffmsg(file1, file2, byte, line); 134 /* NOTREACHED */ 135 } 136 if (ch == '\n') 137 ++line; 138 if (++p1 == e1) { 139 off1 += MMAP_CHUNK; 140 if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) { 141 munmap(m2, MMAP_CHUNK); 142 err(ERR_EXIT, "remmap %s", file1); 143 } 144 e1 = m1 + MMAP_CHUNK; 145 } 146 if (++p2 == e2) { 147 off2 += MMAP_CHUNK; 148 if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) { 149 munmap(m1, MMAP_CHUNK); 150 err(ERR_EXIT, "remmap %s", file2); 151 } 152 e2 = m2 + MMAP_CHUNK; 153 } 154 } 155 munmap(m1, MMAP_CHUNK); 156 munmap(m2, MMAP_CHUNK); 157 158 if (sigaction(SIGSEGV, &oact, NULL)) 159 err(ERR_EXIT, "sigaction()"); 160 161 if (len1 != len2) 162 eofmsg (len1 > len2 ? file2 : file1); 163 if (dfound) 164 exit(DIFF_EXIT); 165 } 166 167 static u_char * 168 remmap(u_char *mem, int fd, off_t offset) 169 { 170 if (mem != NULL) 171 munmap(mem, MMAP_CHUNK); 172 mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset); 173 if (mem == MAP_FAILED) 174 return (NULL); 175 madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL); 176 return (mem); 177 } 178 179 static void 180 segv_handler(int sig __unused) { 181 static const char msg[] = "cmp: Input/output error (caught SIGSEGV)\n"; 182 183 write(STDERR_FILENO, msg, sizeof(msg)); 184 _exit(EXIT_FAILURE); 185 } 186