usr.bin/cmp/cmp.c

   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. 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/cmp.c 216370 2010-12-11 08:32:16Z joel $
  30  *
  31  * @(#) Copyright (c) 1987, 1990, 1993, 1994 The Regents of the University of California.  All rights reserved.
  32  * @(#)cmp.c    8.3 (Berkeley) 4/2/94
  33  */
  34
  35 #include <sys/types.h>
  36 #include <sys/stat.h>
  37
  38 #include <err.h>
  39 #include <errno.h>
  40 #include <fcntl.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include <unistd.h>
  45
  46 #include "extern.h"
  47
  48 int     lflag, sflag, xflag, zflag;
  49
  50 static void usage (void);
  51
  52 int
  53 main(int argc, char **argv)
  54 {
  55         struct stat sb1, sb2;
  56         off_t skip1, skip2;
  57         int ch, fd1, fd2, oflag, special;
  58         const char *file1, *file2;
  59
  60         oflag = O_RDONLY;
  61         while ((ch = getopt(argc, argv, "hlsxz")) != -1)
  62                 switch (ch) {
  63                 case 'h':               /* Don't follow symlinks */
  64                         oflag |= O_NOFOLLOW;
  65                         break;
  66                 case 'l':               /* print all differences */
  67                         lflag = 1;
  68                         break;
  69                 case 's':               /* silent run */
  70                         sflag = 1;
  71                         zflag = 1;
  72                         break;
  73                 case 'x':               /* hex output */
  74                         lflag = 1;
  75                         xflag = 1;
  76                         break;
  77                 case 'z':               /* compare size first */
  78                         zflag = 1;
  79                         break;
  80                 case '?':
  81                 default:
  82                         usage();
  83                 }
  84         argv += optind;
  85         argc -= optind;
  86
  87         if (lflag && sflag)
  88                 errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
  89
  90         if (argc < 2 || argc > 4)
  91                 usage();
  92
  93         /* Backward compatibility -- handle "-" meaning stdin. */
  94         special = 0;
  95         if (strcmp(file1 = argv[0], "-") == 0) {
  96                 special = 1;
  97                 fd1 = 0;
  98                 file1 = "stdin";
  99         }
 100         else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
 101                 if (!sflag)
 102                         err(ERR_EXIT, "%s", file1);
 103                 else
 104                         exit(ERR_EXIT);
 105         }
 106         if (strcmp(file2 = argv[1], "-") == 0) {
 107                 if (special)
 108                         errx(ERR_EXIT,
 109                                 "standard input may only be specified once");
 110                 special = 1;
 111                 fd2 = 0;
 112                 file2 = "stdin";
 113         }
 114         else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
 115                 if (!sflag)
 116                         err(ERR_EXIT, "%s", file2);
 117                 else
 118                         exit(ERR_EXIT);
 119         }
 120
 121         skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
 122         skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
 123
 124         if (fd1 == -1) {
 125                 if (fd2 == -1) {
 126                         c_link(file1, skip1, file2, skip2);
 127                         exit(0);
 128                 } else if (!sflag)
 129                         errx(ERR_EXIT, "%s: Not a symbolic link", file2);
 130                 else
 131                         exit(ERR_EXIT);
 132         } else if (fd2 == -1) {
 133                 if (!sflag)
 134                         errx(ERR_EXIT, "%s: Not a symbolic link", file1);
 135                 else
 136                         exit(ERR_EXIT);
 137         }
 138
 139         if (!special) {
 140                 if (fstat(fd1, &sb1)) {
 141                         if (!sflag)
 142                                 err(ERR_EXIT, "%s", file1);
 143                         else
 144                                 exit(ERR_EXIT);
 145                 }
 146                 if (!S_ISREG(sb1.st_mode))
 147                         special = 1;
 148                 else {
 149                         if (fstat(fd2, &sb2)) {
 150                                 if (!sflag)
 151                                         err(ERR_EXIT, "%s", file2);
 152                                 else
 153                                         exit(ERR_EXIT);
 154                         }
 155                         if (!S_ISREG(sb2.st_mode))
 156                                 special = 1;
 157                 }
 158         }
 159
 160         if (special)
 161                 c_special(fd1, file1, skip1, fd2, file2, skip2);
 162         else {
 163                 if (zflag && sb1.st_size != sb2.st_size) {
 164                         if (!sflag)
 165                                 (void) printf("%s %s differ: size\n",
 166                                     file1, file2);
 167                         exit(DIFF_EXIT);
 168                 }
 169                 c_regular(fd1, file1, skip1, sb1.st_size,
 170                     fd2, file2, skip2, sb2.st_size);
 171         }
 172         exit(0);
 173 }
 174
 175 static void
 176 usage(void)
 177 {
 178
 179         (void)fprintf(stderr,
 180             "usage: cmp [-l | -s | -x] [-hz] file1 file2 [skip1 [skip2]]\n");
 181         exit(ERR_EXIT);
 182 }