bin/cmp/cmp.c

   1 /*      $OpenBSD: cmp.c,v 1.18 2018/03/05 16:57:37 cheloha Exp $      */
   2 /*      $NetBSD: cmp.c,v 1.7 1995/09/08 03:22:56 tls Exp $      */
   3
   4 /*
   5  * Copyright (c) 1987, 1990, 1993, 1994
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <sys/types.h>
  34 #include <sys/stat.h>
  35
  36 #include <err.h>
  37 #include <errno.h>
  38 #include <fcntl.h>
  39 #include <limits.h>
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <unistd.h>
  44
  45 #include "extern.h"
  46
  47 int     lflag, sflag;
  48
  49 static off_t get_skip(const char *, const char *);
  50 static void __dead 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, special;
  58         char *file1, *file2;
  59
  60         if (pledge("stdio rpath", NULL) == -1)
  61                 err(ERR_EXIT, "pledge");
  62
  63         while ((ch = getopt(argc, argv, "ls")) != -1)
  64                 switch (ch) {
  65                 case 'l':               /* print all differences */
  66                         lflag = 1;
  67                         break;
  68                 case 's':               /* silent run */
  69                         sflag = 1;
  70                         break;
  71                 default:
  72                         usage();
  73                 }
  74
  75         argv += optind;
  76         argc -= optind;
  77
  78         if (lflag && sflag)
  79                 errx(ERR_EXIT, "only one of -l and -s may be specified");
  80
  81         if (argc < 2 || argc > 4)
  82                 usage();
  83
  84         /* Backward compatibility -- handle "-" meaning stdin. */
  85         special = 0;
  86         if (strcmp(file1 = argv[0], "-") == 0) {
  87                 special = 1;
  88                 fd1 = 0;
  89                 file1 = "stdin";
  90         } else if ((fd1 = open(file1, O_RDONLY, 0)) == -1)
  91                 fatal("%s", file1);
  92         if (strcmp(file2 = argv[1], "-") == 0) {
  93                 if (special)
  94                         fatalx("standard input may only be specified once");
  95                 special = 1;
  96                 fd2 = 0;
  97                 file2 = "stdin";
  98         } else if ((fd2 = open(file2, O_RDONLY, 0)) == -1)
  99                 fatal("%s", file2);
 100
 101         if (pledge("stdio", NULL) == -1)
 102                 err(ERR_EXIT, "pledge");
 103
 104         skip1 = (argc > 2) ? get_skip(argv[2], "skip1") : 0;
 105         skip2 = (argc == 4) ? get_skip(argv[3], "skip2") : 0;
 106
 107         if (!special) {
 108                 if (fstat(fd1, &sb1) == -1)
 109                         fatal("%s", file1);
 110                 if (!S_ISREG(sb1.st_mode))
 111                         special = 1;
 112                 else {
 113                         if (fstat(fd2, &sb2) == -1)
 114                                 fatal("%s", file2);
 115                         if (!S_ISREG(sb2.st_mode))
 116                                 special = 1;
 117                 }
 118         }
 119
 120         if (special)
 121                 c_special(fd1, file1, skip1, fd2, file2, skip2);
 122         else
 123                 c_regular(fd1, file1, skip1, sb1.st_size,
 124                     fd2, file2, skip2, sb2.st_size);
 125         return 0;
 126 }
 127
 128 static off_t
 129 get_skip(const char *arg, const char *name)
 130 {
 131         off_t skip;
 132         char *ep;
 133
 134         errno = 0;
 135         skip = strtoll(arg, &ep, 0);
 136         if (arg[0] == '\0' || *ep != '\0')
 137                 fatalx("%s is invalid: %s", name, arg);
 138         if (skip < 0)
 139                 fatalx("%s is too small: %s", name, arg);
 140         if (skip == LLONG_MAX && errno == ERANGE)
 141                 fatalx("%s is too large: %s", name, arg);
 142         return skip;
 143 }
 144
 145 static void __dead
 146 usage(void)
 147 {
 148
 149         (void)fprintf(stderr,
 150             "usage: cmp [-l | -s] file1 file2 [skip1 [skip2]]\n");
 151         exit(ERR_EXIT);
 152 }