cmp.c revision 1590
1/* 2 * Copyright (c) 1987, 1990, 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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#ifndef lint 35static char copyright[] = 36"@(#) Copyright (c) 1987, 1990, 1993, 1994\n\ 37 The Regents of the University of California. All rights reserved.\n"; 38#endif /* not lint */ 39 40#ifndef lint 41static char sccsid[] = "@(#)cmp.c 8.3 (Berkeley) 4/2/94"; 42#endif /* not lint */ 43 44#include <sys/types.h> 45#include <sys/stat.h> 46 47#include <err.h> 48#include <fcntl.h> 49#include <stdio.h> 50#include <stdlib.h> 51#include <string.h> 52#include <unistd.h> 53 54#include "extern.h" 55 56int lflag, sflag; 57 58static void usage __P((void)); 59 60int 61main(argc, argv) 62 int argc; 63 char *argv[]; 64{ 65 struct stat sb1, sb2; 66 off_t skip1, skip2; 67 int ch, fd1, fd2, special; 68 char *file1, *file2; 69 70 while ((ch = getopt(argc, argv, "-ls")) != EOF) 71 switch (ch) { 72 case 'l': /* print all differences */ 73 lflag = 1; 74 break; 75 case 's': /* silent run */ 76 sflag = 1; 77 break; 78 case '-': /* stdin (must be after options) */ 79 --optind; 80 goto endargs; 81 case '?': 82 default: 83 usage(); 84 } 85endargs: 86 argv += optind; 87 argc -= optind; 88 89 if (lflag && sflag) 90 errx(ERR_EXIT, "only one of -l and -s may be specified"); 91 92 if (argc < 2 || argc > 4) 93 usage(); 94 95 /* Backward compatibility -- handle "-" meaning stdin. */ 96 special = 0; 97 if (strcmp(file1 = argv[0], "-") == 0) { 98 special = 1; 99 fd1 = 0; 100 file1 = "stdin"; 101 } 102 else if ((fd1 = open(file1, O_RDONLY, 0)) < 0) 103 err(ERR_EXIT, "%s", file1); 104 if (strcmp(file2 = argv[1], "-") == 0) { 105 if (special) 106 errx(ERR_EXIT, 107 "standard input may only be specified once"); 108 special = 1; 109 fd2 = 0; 110 file2 = "stdin"; 111 } 112 else if ((fd2 = open(file2, O_RDONLY, 0)) < 0) 113 err(ERR_EXIT, "%s", file2); 114 115 skip1 = argc > 2 ? strtol(argv[2], NULL, 10) : 0; 116 skip2 = argc == 4 ? strtol(argv[3], NULL, 10) : 0; 117 118 if (!special) { 119 if (fstat(fd1, &sb1)) 120 err(ERR_EXIT, "%s", file1); 121 if (!S_ISREG(sb1.st_mode)) 122 special = 1; 123 else { 124 if (fstat(fd2, &sb2)) 125 err(ERR_EXIT, "%s", file2); 126 if (!S_ISREG(sb2.st_mode)) 127 special = 1; 128 } 129 } 130 131 if (special) 132 c_special(fd1, file1, skip1, fd2, file2, skip2); 133 else 134 c_regular(fd1, file1, skip1, sb1.st_size, 135 fd2, file2, skip2, sb2.st_size); 136 exit(0); 137} 138 139static void 140usage() 141{ 142 143 (void)fprintf(stderr, 144 "usage: cmp [-l | s] file1 file2 [skip1 [skip2]]\n"); 145 exit(ERR_EXIT); 146} 147