usr.bin/cmp/cmp.c

   1 /*
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 1987, 1990, 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  * $FreeBSD: head/usr.bin/cmp/cmp.c 216370 2010-12-11 08:32:16Z joel $
  32  *
  33  * @(#) Copyright (c) 1987, 1990, 1993, 1994 The Regents of the University of California.  All rights reserved.
  34  * @(#)cmp.c    8.3 (Berkeley) 4/2/94
  35  */
  36
  37 #include <sys/types.h>
  38 #include <sys/stat.h>
  39
  40 #include <err.h>
  41 #include <errno.h>
  42 #include <fcntl.h>
  43 #include <getopt.h>
  44 #include <nl_types.h>
  45 #include <stdbool.h>
  46 #include <stdio.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include <unistd.h>
  50
  51 #include "extern.h"
  52
  53 bool    lflag, sflag, xflag, zflag;
  54
  55 static const struct option long_opts[] =
  56 {
  57         {"verbose",     no_argument,            NULL, 'l'},
  58         {"silent",      no_argument,            NULL, 's'},
  59         {"quiet",       no_argument,            NULL, 's'},
  60         {NULL,          no_argument,            NULL, 0}
  61 };
  62
  63 static void usage(void);
  64
  65 int
  66 main(int argc, char *argv[])
  67 {
  68         struct stat sb1, sb2;
  69         off_t skip1, skip2;
  70         int ch, fd1, fd2, oflag;
  71         bool special;
  72         const char *file1, *file2;
  73
  74         oflag = O_RDONLY;
  75         while ((ch = getopt_long(argc, argv, "+hlsxz", long_opts, NULL)) != -1)
  76                 switch (ch) {
  77                 case 'h':               /* Don't follow symlinks */
  78                         oflag |= O_NOFOLLOW;
  79                         break;
  80                 case 'l':               /* print all differences */
  81                         lflag = true;
  82                         break;
  83                 case 's':               /* silent run */
  84                         sflag = true;
  85                         break;
  86                 case 'x':               /* hex output */
  87                         lflag = true;
  88                         xflag = true;
  89                         break;
  90                 case 'z':               /* compare size first */
  91                         zflag = true;
  92                         break;
  93                 case '?':
  94                 default:
  95                         usage();
  96                 }
  97         argv += optind;
  98         argc -= optind;
  99
 100         if (lflag && sflag)
 101                 errx(ERR_EXIT, "specifying -s with -l or -x is not permitted");
 102
 103         if (argc < 2 || argc > 4)
 104                 usage();
 105
 106         /* Backward compatibility -- handle "-" meaning stdin. */
 107         special = false;
 108         if (strcmp(file1 = argv[0], "-") == 0) {
 109                 special = true;
 110                 fd1 = STDIN_FILENO;
 111                 file1 = "stdin";
 112         } else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
 113                 if (!sflag)
 114                         err(ERR_EXIT, "%s", file1);
 115                 else
 116                         exit(ERR_EXIT);
 117         }
 118         if (strcmp(file2 = argv[1], "-") == 0) {
 119                 if (special)
 120                         errx(ERR_EXIT,
 121                                 "standard input may only be specified once");
 122                 special = true;
 123                 fd2 = STDIN_FILENO;
 124                 file2 = "stdin";
 125         } else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
 126                 if (!sflag)
 127                         err(ERR_EXIT, "%s", file2);
 128                 else
 129                         exit(ERR_EXIT);
 130         }
 131
 132         skip1 = argc > 2 ? strtol(argv[2], NULL, 0) : 0;
 133         skip2 = argc == 4 ? strtol(argv[3], NULL, 0) : 0;
 134
 135         if (sflag && skip1 == 0 && skip2 == 0)
 136                 zflag = true;
 137
 138         if (fd1 == -1) {
 139                 if (fd2 == -1) {
 140                         c_link(file1, skip1, file2, skip2);
 141                         exit(0);
 142                 } else if (!sflag)
 143                         errx(ERR_EXIT, "%s: Not a symbolic link", file2);
 144                 else
 145                         exit(ERR_EXIT);
 146         } else if (fd2 == -1) {
 147                 if (!sflag)
 148                         errx(ERR_EXIT, "%s: Not a symbolic link", file1);
 149                 else
 150                         exit(ERR_EXIT);
 151         }
 152
 153         if (!special) {
 154                 if (fstat(fd1, &sb1)) {
 155                         if (!sflag)
 156                                 err(ERR_EXIT, "%s", file1);
 157                         else
 158                                 exit(ERR_EXIT);
 159                 }
 160                 if (!S_ISREG(sb1.st_mode))
 161                         special = true;
 162                 else {
 163                         if (fstat(fd2, &sb2)) {
 164                                 if (!sflag)
 165                                         err(ERR_EXIT, "%s", file2);
 166                                 else
 167                                         exit(ERR_EXIT);
 168                         }
 169                         if (!S_ISREG(sb2.st_mode))
 170                                 special = true;
 171                 }
 172         }
 173
 174         if (special)
 175                 c_special(fd1, file1, skip1, fd2, file2, skip2);
 176         else {
 177                 if (zflag && sb1.st_size != sb2.st_size) {
 178                         if (!sflag)
 179                                 (void) printf("%s %s differ: size\n",
 180                                     file1, file2);
 181                         exit(DIFF_EXIT);
 182                 }
 183                 c_regular(fd1, file1, skip1, sb1.st_size,
 184                     fd2, file2, skip2, sb2.st_size);
 185         }
 186         exit(0);
 187 }
 188
 189 static void
 190 usage(void)
 191 {
 192
 193         (void)fprintf(stderr,
 194             "usage: cmp [-l | -s | -x] [-hz] file1 file2 [skip1 [skip2]]\n");
 195         exit(ERR_EXIT);
 196 }