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 #endif 34 35 #include <sys/cdefs.h> 36 #include <sys/param.h> 37 #include <sys/mman.h> 38 #include <sys/stat.h> 39 40 #include <capsicum_helpers.h> 41 #include <err.h> 42 #include <limits.h> 43 #include <signal.h> 44 #include <stdlib.h> 45 #include <stdio.h> 46 #include <unistd.h> 47 48 #include "extern.h" 49 50 static u_char *remmap(u_char *, int, off_t); 51 static void segv_handler(int); 52 #define MMAP_CHUNK (8*1024*1024) 53 54 #define ROUNDPAGE(i) ((i) & ~pagemask) 55 56 void 57 c_regular(int fd1, const char *file1, off_t skip1, off_t len1, 58 int fd2, const char *file2, off_t skip2, off_t len2, off_t limit) 59 { 60 struct sigaction act, oact; 61 cap_rights_t rights; 62 u_char ch, *p1, *p2, *m1, *m2, *e1, *e2; 63 off_t byte, length, line; 64 off_t pagemask, off1, off2; 65 size_t pagesize; 66 int dfound; 67 68 if (skip1 > len1) 69 eofmsg(file1); 70 len1 -= skip1; 71 if (skip2 > len2) 72 eofmsg(file2); 73 len2 -= skip2; 74 75 if (sflag && len1 != len2) 76 exit(DIFF_EXIT); 77 78 pagesize = getpagesize(); 79 pagemask = (off_t)pagesize - 1; 80 off1 = ROUNDPAGE(skip1); 81 off2 = ROUNDPAGE(skip2); 82 83 length = MIN(len1, len2); 84 if (limit > 0) 85 length = MIN(length, limit); 86 87 if ((m1 = remmap(NULL, fd1, off1)) == NULL) { 88 c_special(fd1, file1, skip1, fd2, file2, skip2, limit); 89 return; 90 } 91 92 if ((m2 = remmap(NULL, fd2, off2)) == NULL) { 93 munmap(m1, MMAP_CHUNK); 94 c_special(fd1, file1, skip1, fd2, file2, skip2, limit); 95 return; 96 } 97 98 if (caph_rights_limit(fd1, cap_rights_init(&rights, CAP_MMAP_R)) < 0) 99 err(1, "unable to limit rights for %s", file1); 100 if (caph_rights_limit(fd2, cap_rights_init(&rights, CAP_MMAP_R)) < 0) 101 err(1, "unable to limit rights for %s", file2); 102 if (caph_enter() < 0) 103 err(ERR_EXIT, "unable to enter capability mode"); 104 105 sigemptyset(&act.sa_mask); 106 act.sa_flags = SA_NODEFER; 107 act.sa_handler = segv_handler; 108 if (sigaction(SIGSEGV, &act, &oact)) 109 err(ERR_EXIT, "sigaction()"); 110 111 dfound = 0; 112 e1 = m1 + MMAP_CHUNK; 113 e2 = m2 + MMAP_CHUNK; 114 p1 = m1 + (skip1 - off1); 115 p2 = m2 + (skip2 - off2); 116 117 for (byte = line = 1; length--; ++byte) { 118 #ifdef SIGINFO 119 if (info) { 120 (void)fprintf(stderr, "%s %s char %zu line %zu\n", 121 file1, file2, (size_t)byte, (size_t)line); 122 info = 0; 123 } 124 #endif 125 if ((ch = *p1) != *p2) { 126 if (xflag) { 127 dfound = 1; 128 (void)printf("%08llx %02x %02x\n", 129 (long long)byte - 1, ch, *p2); 130 } else if (lflag) { 131 dfound = 1; 132 if (bflag) 133 (void)printf("%6lld %3o %c %3o %c\n", 134 (long long)byte, ch, ch, *p2, *p2); 135 else 136 (void)printf("%6lld %3o %3o\n", 137 (long long)byte, ch, *p2); 138 } else 139 diffmsg(file1, file2, byte, line, ch, *p2); 140 /* NOTREACHED */ 141 } 142 if (ch == '\n') 143 ++line; 144 if (++p1 == e1) { 145 off1 += MMAP_CHUNK; 146 if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) { 147 munmap(m2, MMAP_CHUNK); 148 err(ERR_EXIT, "remmap %s", file1); 149 } 150 e1 = m1 + MMAP_CHUNK; 151 } 152 if (++p2 == e2) { 153 off2 += MMAP_CHUNK; 154 if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) { 155 munmap(m1, MMAP_CHUNK); 156 err(ERR_EXIT, "remmap %s", file2); 157 } 158 e2 = m2 + MMAP_CHUNK; 159 } 160 } 161 munmap(m1, MMAP_CHUNK); 162 munmap(m2, MMAP_CHUNK); 163 164 if (sigaction(SIGSEGV, &oact, NULL)) 165 err(ERR_EXIT, "sigaction()"); 166 167 if (len1 != len2) 168 eofmsg (len1 > len2 ? file2 : file1); 169 if (dfound) 170 exit(DIFF_EXIT); 171 } 172 173 static u_char * 174 remmap(u_char *mem, int fd, off_t offset) 175 { 176 if (mem != NULL) 177 munmap(mem, MMAP_CHUNK); 178 mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset); 179 if (mem == MAP_FAILED) 180 return (NULL); 181 madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL); 182 return (mem); 183 } 184 185 static void 186 segv_handler(int sig __unused) { 187 static const char msg[] = "cmp: Input/output error (caught SIGSEGV)\n"; 188 189 write(STDERR_FILENO, msg, sizeof(msg)); 190 _exit(EXIT_FAILURE); 191 } 192