1/***************************************************************************
2 * binoffset.c
3 * (C) 2002 Randy Dunlap <rdunlap@xenotime.net>
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
41char		*progname;
42char		*inputname;
43int		inputfd;
44unsigned int	bix;			/* buf index */
45unsigned char	patterns [PAT_SIZE] = {0}; /* byte-sized pattern array */
46int		pat_len;		/* actual number of pattern bytes */
47unsigned char	*madr;			/* mmap address */
48size_t		filesize;
49int		num_matches = 0;
50off_t		firstloc = 0;
51
52void 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
61void 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
84void 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
98size_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
106size_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
118int 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 */
164