brandelf.c revision 76224 
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 * $FreeBSD: head/usr.bin/brandelf/brandelf.c 76224 2001-05-02 23:56:21Z obrien $
29 */
30
31#include <sys/types.h>
32#include <sys/elf_common.h>
33#include <fcntl.h>
34#include <stdio.h>
35#include <stdlib.h>
36#include <string.h>
37#include <unistd.h>
38#include <sys/errno.h>
39#include <err.h>
40
41static int elftype(const char *);
42static const char *iselftype(int);
43static void printelftypes(void);
44static void usage __P((void));
45
46struct ELFtypes {
47	const char *str;
48	int value;
49};
50/* XXX - any more types? */
51static struct ELFtypes elftypes[] = {
52	{ "FreeBSD",	ELFOSABI_FREEBSD },
53	{ "Linux",	ELFOSABI_LINUX },
54	{ "Solaris",	ELFOSABI_SOLARIS },
55	{ "SVR4",	ELFOSABI_SYSV }
56};
57
58int
59main(int argc, char **argv)
60{
61
62	const char *strtype = "FreeBSD";
63	int type = ELFOSABI_FREEBSD;
64	int retval = 0;
65	int ch, change = 0, verbose = 0, force = 0, listed = 0;
66
67	while ((ch = getopt(argc, argv, "f:lt:v")) != -1)
68		switch (ch) {
69		case 'f':
70			if (change)
71				errx(1, "f option incompatible with t option");
72			force = 1;
73			type = atoi(optarg);
74			if (errno == ERANGE || type < 0 || type > 255) {
75				warnx("invalid argument to option f: %s",
76				    optarg);
77				usage();
78			}
79			break;
80		case 'l':
81			printelftypes();
82			listed = 1;
83			break;
84		case 'v':
85			verbose = 1;
86			break;
87		case 't':
88			if (force)
89				errx(1, "t option incompatible with f option");
90			change = 1;
91			strtype = optarg;
92			break;
93		default:
94			usage();
95	}
96	argc -= optind;
97	argv += optind;
98	if (!argc) {
99		if (listed)
100			exit(0);
101		else {
102			warnx("no file(s) specified");
103			usage();
104		}
105	}
106
107	if (!force && (type = elftype(strtype)) == -1) {
108		warnx("invalid ELF type '%s'", strtype);
109		printelftypes();
110		usage();
111	}
112
113	while (argc) {
114		int fd;
115		char buffer[EI_NIDENT];
116
117		if ((fd = open(argv[0], change || force ? O_RDWR : O_RDONLY, 0)) < 0) {
118			warn("error opening file %s", argv[0]);
119			retval = 1;
120			goto fail;
121		}
122		if (read(fd, buffer, EI_NIDENT) < EI_NIDENT) {
123			warnx("file '%s' too short", argv[0]);
124			retval = 1;
125			goto fail;
126		}
127		if (buffer[0] != ELFMAG0 || buffer[1] != ELFMAG1 ||
128		    buffer[2] != ELFMAG2 || buffer[3] != ELFMAG3) {
129			warnx("file '%s' is not ELF format", argv[0]);
130			retval = 1;
131			goto fail;
132		}
133		if (!change && !force) {
134			fprintf(stdout,
135				"File '%s' is of brand '%s' (%u).\n",
136				argv[0], iselftype(buffer[EI_OSABI]),
137				buffer[EI_OSABI]);
138			if (!iselftype(type)) {
139				warnx("ELF ABI Brand '%u' is unknown",
140				      type);
141				printelftypes();
142			}
143		}
144		else {
145			buffer[EI_OSABI] = type;
146			lseek(fd, 0, SEEK_SET);
147			if (write(fd, buffer, EI_NIDENT) != EI_NIDENT) {
148				warn("error writing %s %d", argv[0], fd);
149				retval = 1;
150				goto fail;
151			}
152		}
153fail:
154		close(fd);
155		argc--;
156		argv++;
157	}
158
159	return retval;
160}
161
162static void
163usage()
164{
165fprintf(stderr, "usage: brandelf [-f ELF ABI number] [-v] [-l] [-t string] file ...\n");
166	exit(1);
167}
168
169static const char *
170iselftype(int elftype)
171{
172	int elfwalk;
173
174	for (elfwalk = 0;
175	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
176	     elfwalk++)
177		if (elftype == elftypes[elfwalk].value)
178			return elftypes[elfwalk].str;
179	return 0;
180}
181
182static int
183elftype(const char *elfstrtype)
184{
185	int elfwalk;
186
187	for (elfwalk = 0;
188	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
189	     elfwalk++)
190		if (strcmp(elfstrtype, elftypes[elfwalk].str) == 0)
191			return elftypes[elfwalk].value;
192	return -1;
193}
194
195static void
196printelftypes()
197{
198	int elfwalk;
199
200	fprintf(stderr, "known ELF types are: ");
201	for (elfwalk = 0;
202	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
203	     elfwalk++)
204		fprintf(stderr, "%s(%u) ", elftypes[elfwalk].str,
205			elftypes[elfwalk].value);
206	fprintf(stderr, "\n");
207}
208