brandelf.c revision 28620 
1/*-
2 * Copyright (c) 1996 S�ren Schmidt
3 * 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 *    in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software withough specific prior written permission
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 *  $Id: brandelf.c,v 1.7 1997/06/23 06:47:12 charnier Exp $
29 */
30
31#include <elf.h>
32#include <fcntl.h>
33#include <stdio.h>
34#include <stdlib.h>
35#include <string.h>
36#include <unistd.h>
37#include <err.h>
38
39static void usage __P((void));
40
41int
42main(int argc, char **argv)
43{
44
45	const char *type = "FreeBSD";
46	int retval = 0;
47	int ch, change = 0, verbose = 0;
48
49	while ((ch = getopt(argc, argv, "t:v")) != -1)
50		switch (ch) {
51		case 'v':
52			verbose = 1;
53			break;
54		case 't':
55			change = 1;
56			type = optarg;
57			break;
58		default:
59			usage();
60	}
61	argc -= optind;
62	argv += optind;
63	if (!argc)
64		errx(1, "no file(s) specified");
65	while (argc) {
66		int fd;
67		char buffer[EI_NIDENT];
68		char string[(EI_NIDENT-EI_BRAND)+1];
69
70		if ((fd = open(argv[0], change? O_RDWR: O_RDONLY, 0)) < 0) {
71			warn("error opening file %s", argv[0]);
72			retval = 1;
73			goto fail;
74
75		}
76		if (read(fd, buffer, EI_NIDENT) < EI_NIDENT) {
77			warnx("file '%s' too short", argv[0]);
78			retval = 1;
79			goto fail;
80		}
81		if (buffer[0] != ELFMAG0 || buffer[1] != ELFMAG1 ||
82		    buffer[2] != ELFMAG2 || buffer[3] != ELFMAG3) {
83			warnx("file '%s' is not ELF format", argv[0]);
84			retval = 1;
85			goto fail;
86		}
87		if (!change) {
88			bzero(string, sizeof(string));
89			strncpy(string, &buffer[EI_BRAND], EI_NIDENT-EI_BRAND);
90			if (strlen(string)) {
91				fprintf(stdout, "File '%s' is of brand '%s'.\n",
92					argv[0], string);
93			}
94			else
95				fprintf(stdout, "File '%s' has no branding.\n",
96					argv[0]);
97		}
98		else {
99			strncpy(&buffer[EI_BRAND], type, EI_NIDENT-EI_BRAND);
100			lseek(fd, 0, SEEK_SET);
101			if (write(fd, buffer, EI_NIDENT) != EI_NIDENT) {
102				warnx("error writing %s", argv[0]);
103				retval = 1;
104				goto fail;
105			}
106		}
107fail:
108		argc--;
109		argv++;
110	}
111
112	return retval;
113}
114
115static void
116usage()
117{
118	fprintf(stderr, "usage: brandelf [-t string] file ...\n");
119	exit(1);
120}
121