brandelf.c revision 59342 
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 59342 2000-04-18 02:39:26Z obrien $
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 <sys/errno.h>
38#include <err.h>
39
40static int elftype(const char *);
41static const char *iselftype(int);
42static void printelftypes(void);
43static void usage __P((void));
44
45struct ELFtypes {
46	const char *str;
47	int value;
48};
49/* XXX - any more types? */
50static struct ELFtypes elftypes[] = {
51	{ "FreeBSD",	ELFOSABI_FREEBSD },
52	{ "SVR4",	ELFOSABI_SYSV },
53	{ "Linux",	ELFOSABI_LINUX }
54};
55
56int
57main(int argc, char **argv)
58{
59
60	const char *strtype = "FreeBSD";
61	int type = ELFOSABI_FREEBSD;
62	int retval = 0;
63	int ch, change = 0, verbose = 0, force = 0, listed = 0;
64
65	while ((ch = getopt(argc, argv, "f:lt:v")) != -1)
66		switch (ch) {
67		case 'f':
68			if (change)
69				errx(1, "f option incompatable with t option");
70			force = 1;
71			type = atoi(optarg);
72			if (errno == ERANGE || type < 0 || type > 255) {
73				warnx("invalid argument to option f: %s",
74				    optarg);
75				usage();
76			}
77			break;
78		case 'l':
79			printelftypes();
80			listed = 1;
81			break;
82		case 'v':
83			verbose = 1;
84			break;
85		case 't':
86			if (force)
87				errx(1, "t option incompatable with f option");
88			change = 1;
89			strtype = optarg;
90			break;
91		default:
92			usage();
93	}
94	argc -= optind;
95	argv += optind;
96	if (!argc) {
97		if (listed)
98			exit(0);
99		else {
100			warnx("no file(s) specified");
101			usage();
102		}
103	}
104
105	if (!force && (type = elftype(strtype)) == -1) {
106		warnx("invalid ELF type '%s'", strtype);
107		printelftypes();
108		usage();
109	}
110
111	while (argc) {
112		int fd;
113		char buffer[EI_NIDENT];
114
115		if ((fd = open(argv[0], change || force ? O_RDWR : O_RDONLY, 0)) < 0) {
116			warn("error opening file %s", argv[0]);
117			retval = 1;
118			goto fail;
119		}
120		if (read(fd, buffer, EI_NIDENT) < EI_NIDENT) {
121			warnx("file '%s' too short", argv[0]);
122			retval = 1;
123			goto fail;
124		}
125		if (buffer[0] != ELFMAG0 || buffer[1] != ELFMAG1 ||
126		    buffer[2] != ELFMAG2 || buffer[3] != ELFMAG3) {
127			warnx("file '%s' is not ELF format", argv[0]);
128			retval = 1;
129			goto fail;
130		}
131		if (!change && !force) {
132			fprintf(stdout,
133				"File '%s' is of brand '%s' (%u).\n",
134				argv[0], iselftype(buffer[EI_OSABI]),
135				buffer[EI_OSABI]);
136			if (!iselftype(type)) {
137				warnx("ELF ABI Brand '%u' is unknown",
138				      type);
139				printelftypes();
140			}
141		}
142		else {
143			buffer[EI_OSABI] = type;
144			lseek(fd, 0, SEEK_SET);
145			if (write(fd, buffer, EI_NIDENT) != EI_NIDENT) {
146				warn("error writing %s %d", argv[0], fd);
147				retval = 1;
148				goto fail;
149			}
150		}
151fail:
152		argc--;
153		argv++;
154	}
155
156	return retval;
157}
158
159static void
160usage()
161{
162fprintf(stderr, "usage: brandelf [-f ELF ABI number] [-v] [-l] [-t string] file ...\n");
163	exit(1);
164}
165
166static const char *
167iselftype(int elftype)
168{
169	int elfwalk;
170
171	for (elfwalk = 0;
172	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
173	     elfwalk++)
174		if (elftype == elftypes[elfwalk].value)
175			return elftypes[elfwalk].str;
176	return 0;
177}
178
179static int
180elftype(const char *elfstrtype)
181{
182	int elfwalk;
183
184	for (elfwalk = 0;
185	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
186	     elfwalk++)
187		if (strcmp(elfstrtype, elftypes[elfwalk].str) == 0)
188			return elftypes[elfwalk].value;
189	return -1;
190}
191
192static void
193printelftypes()
194{
195	int elfwalk;
196
197	fprintf(stderr, "known ELF types are: ");
198	for (elfwalk = 0;
199	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
200	     elfwalk++)
201		fprintf(stderr, "%s(%u) ", elftypes[elfwalk].str,
202			elftypes[elfwalk].value);
203	fprintf(stderr, "\n");
204}
205