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 #include <sys/param.h> 40 #include <sys/mman.h> 41 #include <sys/stat.h> 42 43 #include <capsicum_helpers.h> 44 #include <err.h> 45 #include <limits.h> 46 #include <signal.h> 47 #include <stdbool.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 int 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, off_t limit) 63 { 64 struct sigaction act, oact; 65 cap_rights_t rights; 66 u_char ch, *p1, *p2, *m1, *m2, *e1, *e2; 67 off_t byte, length, line; 68 off_t pagemask, off1, off2; 69 size_t pagesize; 70 int dfound; 71 72 if (skip1 > len1) { 73 eofmsg(file1); 74 return (DIFF_EXIT); 75 } 76 len1 -= skip1; 77 if (skip2 > len2) { 78 eofmsg(file2); 79 return (DIFF_EXIT); 80 } 81 len2 -= skip2; 82 83 if (sflag && len1 != len2) 84 return (DIFF_EXIT); 85 86 pagesize = getpagesize(); 87 pagemask = (off_t)pagesize - 1; 88 off1 = ROUNDPAGE(skip1); 89 off2 = ROUNDPAGE(skip2); 90 91 length = MIN(len1, len2); 92 if (limit > 0) 93 length = MIN(length, limit); 94 95 if ((m1 = remmap(NULL, fd1, off1)) == NULL) { 96 return (c_special(fd1, file1, skip1, fd2, file2, skip2, limit)); 97 } 98 99 if ((m2 = remmap(NULL, fd2, off2)) == NULL) { 100 munmap(m1, MMAP_CHUNK); 101 return (c_special(fd1, file1, skip1, fd2, file2, skip2, limit)); 102 } 103 104 if (caph_rights_limit(fd1, cap_rights_init(&rights, CAP_MMAP_R)) < 0) 105 err(1, "unable to limit rights for %s", file1); 106 if (caph_rights_limit(fd2, cap_rights_init(&rights, CAP_MMAP_R)) < 0) 107 err(1, "unable to limit rights for %s", file2); 108 if (caph_enter() < 0) 109 err(ERR_EXIT, "unable to enter capability mode"); 110 111 sigemptyset(&act.sa_mask); 112 act.sa_flags = SA_NODEFER; 113 act.sa_handler = segv_handler; 114 if (sigaction(SIGSEGV, &act, &oact)) 115 err(ERR_EXIT, "sigaction()"); 116 117 dfound = 0; 118 e1 = m1 + MMAP_CHUNK; 119 e2 = m2 + MMAP_CHUNK; 120 p1 = m1 + (skip1 - off1); 121 p2 = m2 + (skip2 - off2); 122 123 for (byte = line = 1; length--; ++byte) { 124 #ifdef SIGINFO 125 if (info) { 126 (void)fprintf(stderr, "%s %s char %zu line %zu\n", 127 file1, file2, (size_t)byte, (size_t)line); 128 info = 0; 129 } 130 #endif 131 if ((ch = *p1) != *p2) { 132 dfound = 1; 133 if (xflag) { 134 (void)printf("%08llx %02x %02x\n", 135 (long long)byte - 1, ch, *p2); 136 } else if (lflag) { 137 if (bflag) 138 (void)printf("%6lld %3o %c %3o %c\n", 139 (long long)byte, ch, ch, *p2, *p2); 140 else 141 (void)printf("%6lld %3o %3o\n", 142 (long long)byte, ch, *p2); 143 } else { 144 diffmsg(file1, file2, byte, line, ch, *p2); 145 return (DIFF_EXIT); 146 } 147 } 148 if (ch == '\n') 149 ++line; 150 if (++p1 == e1) { 151 off1 += MMAP_CHUNK; 152 if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) { 153 munmap(m2, MMAP_CHUNK); 154 err(ERR_EXIT, "remmap %s", file1); 155 } 156 e1 = m1 + MMAP_CHUNK; 157 } 158 if (++p2 == e2) { 159 off2 += MMAP_CHUNK; 160 if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) { 161 munmap(m1, MMAP_CHUNK); 162 err(ERR_EXIT, "remmap %s", file2); 163 } 164 e2 = m2 + MMAP_CHUNK; 165 } 166 } 167 munmap(m1, MMAP_CHUNK); 168 munmap(m2, MMAP_CHUNK); 169 170 if (sigaction(SIGSEGV, &oact, NULL)) 171 err(ERR_EXIT, "sigaction()"); 172 173 if (len1 != len2) { 174 eofmsg(len1 > len2 ? file2 : file1); 175 return (DIFF_EXIT); 176 } 177 return (dfound ? DIFF_EXIT : 0); 178 } 179 180 static u_char * 181 remmap(u_char *mem, int fd, off_t offset) 182 { 183 if (mem != NULL) 184 munmap(mem, MMAP_CHUNK); 185 mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset); 186 if (mem == MAP_FAILED) 187 return (NULL); 188 madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL); 189 return (mem); 190 } 191 192 static void 193 segv_handler(int sig __unused) { 194 static const char msg[] = "cmp: Input/output error (caught SIGSEGV)\n"; 195 196 write(STDERR_FILENO, msg, sizeof(msg)); 197 _exit(EXIT_FAILURE); 198 } 199