scripts/binoffset.c

   1 /***************************************************************************
   2  * binoffset.c
   3  * (C) 2002 Randy Dunlap <rddunlap@osdl.org>
   4
   5 #   This program is free software; you can redistribute it and/or modify
   6 #   it under the terms of the GNU General Public License as published by
   7 #   the Free Software Foundation; either version 2 of the License, or
   8 #   (at your option) any later version.
   9 #
  10 #   This program is distributed in the hope that it will be useful,
  11 #   but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 #   GNU General Public License for more details.
  14 #
  15 #   You should have received a copy of the GNU General Public License
  16 #   along with this program; if not, write to the Free Software
  17 #   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18
  19 # binoffset.c:
  20 # - searches a (binary) file for a specified (binary) pattern
  21 # - returns the offset of the located pattern or ~0 if not found
  22 # - exits with exit status 0 normally or non-0 if pattern is not found
  23 #   or any other error occurs.
  24
  25 ****************************************************************/
  26
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <errno.h>
  31 #include <unistd.h>
  32 #include <fcntl.h>
  33 #include <sys/types.h>
  34 #include <sys/stat.h>
  35 #include <sys/mman.h>
  36
  37 #define VERSION         "0.1"
  38 #define BUF_SIZE        (16 * 1024)
  39 #define PAT_SIZE        100
  40
  41 char            *progname;
  42 char            *inputname;
  43 int             inputfd;
  44 unsigned int    bix;                    /* buf index */
  45 unsigned char   patterns [PAT_SIZE] = {0}; /* byte-sized pattern array */
  46 int             pat_len;                /* actual number of pattern bytes */
  47 unsigned char   *madr;                  /* mmap address */
  48 size_t          filesize;
  49 int             num_matches = 0;
  50 off_t           firstloc = 0;
  51
  52 void usage (void)
  53 {
  54         fprintf (stderr, "%s ver. %s\n", progname, VERSION);
  55         fprintf (stderr, "usage:  %s filename pattern_bytes\n",
  56                         progname);
  57         fprintf (stderr, "        [prints location of pattern_bytes in file]\n");
  58         exit (1);
  59 }
  60
  61 void get_pattern (int pat_count, char *pats [])
  62 {
  63         int ix, err, tmp;
  64
  65 #ifdef DEBUG
  66         fprintf (stderr,"get_pattern: count = %d\n", pat_count);
  67         for (ix = 0; ix < pat_count; ix++)
  68                 fprintf (stderr, "  pat # %d:  [%s]\n", ix, pats[ix]);
  69 #endif
  70
  71         for (ix = 0; ix < pat_count; ix++) {
  72                 tmp = 0;
  73                 err = sscanf (pats[ix], "%5i", &tmp);
  74                 if (err != 1 || tmp > 0xff) {
  75                         fprintf (stderr, "pattern or value error in pattern # %d [%s]\n",
  76                                         ix, pats[ix]);
  77                         usage ();
  78                 }
  79                 patterns [ix] = tmp;
  80         }
  81         pat_len = pat_count;
  82 }
  83
  84 void search_pattern (void)
  85 {
  86         for (bix = 0; bix < filesize; bix++) {
  87                 if (madr[bix] == patterns[0]) {
  88                         if (memcmp (&madr[bix], patterns, pat_len) == 0) {
  89                                 if (num_matches == 0)
  90                                         firstloc = bix;
  91                                 num_matches++;
  92                         }
  93                 }
  94         }
  95 }
  96
  97 #ifdef NOTDEF
  98 size_t get_filesize (int fd)
  99 {
 100         off_t end_off = lseek (fd, 0, SEEK_END);
 101         lseek (fd, 0, SEEK_SET);
 102         return (size_t) end_off;
 103 }
 104 #endif
 105
 106 size_t get_filesize (int fd)
 107 {
 108         int err;
 109         struct stat stat;
 110
 111         err = fstat (fd, &stat);
 112         fprintf (stderr, "filesize: %ld\n", err < 0 ? (long)err : stat.st_size);
 113         if (err < 0)
 114                 return err;
 115         return (size_t) stat.st_size;
 116 }
 117
 118 int main (int argc, char *argv [])
 119 {
 120         progname = argv[0];
 121
 122         if (argc < 3)
 123                 usage ();
 124
 125         get_pattern (argc - 2, argv + 2);
 126
 127         inputname = argv[1];
 128
 129         inputfd = open (inputname, O_RDONLY);
 130         if (inputfd == -1) {
 131                 fprintf (stderr, "%s: cannot open '%s'\n",
 132                                 progname, inputname);
 133                 exit (3);
 134         }
 135
 136         filesize = get_filesize (inputfd);
 137
 138         madr = mmap (0, filesize, PROT_READ, MAP_PRIVATE, inputfd, 0);
 139         if (madr == MAP_FAILED) {
 140                 fprintf (stderr, "mmap error = %d\n", errno);
 141                 close (inputfd);
 142                 exit (4);
 143         }
 144
 145         search_pattern ();
 146
 147         if (munmap (madr, filesize))
 148                 fprintf (stderr, "munmap error = %d\n", errno);
 149
 150         if (close (inputfd))
 151                 fprintf (stderr, "%s: error %d closing '%s'\n",
 152                                 progname, errno, inputname);
 153
 154         fprintf (stderr, "number of pattern matches = %d\n", num_matches);
 155         if (num_matches == 0)
 156                 firstloc = ~0;
 157         printf ("%ld\n", firstloc);
 158         fprintf (stderr, "%ld\n", firstloc);
 159
 160         exit (num_matches ? 0 : 2);
 161 }
 162
 163 /* end binoffset.c */