brandelf.c revision 145807 
1/*-
2 * Copyright (c) 2000, 2001 David O'Brien
3 * Copyright (c) 1996 S�ren Schmidt
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer
11 *    in this position and unchanged.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 *    derived from this software without specific prior written permission
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: head/usr.bin/brandelf/brandelf.c 145807 2005-05-02 17:19:33Z green $");
32
33#include <sys/types.h>
34#include <sys/elf_common.h>
35#include <sys/errno.h>
36#include <err.h>
37#include <fcntl.h>
38#include <stdio.h>
39#include <stdlib.h>
40#include <string.h>
41#include <unistd.h>
42
43static int elftype(const char *);
44static const char *iselftype(int);
45static void printelftypes(void);
46static void usage(void);
47
48struct ELFtypes {
49	const char *str;
50	int value;
51};
52/* XXX - any more types? */
53static struct ELFtypes elftypes[] = {
54	{ "FreeBSD",	ELFOSABI_FREEBSD },
55	{ "Linux",	ELFOSABI_LINUX },
56	{ "Solaris",	ELFOSABI_SOLARIS },
57	{ "SVR4",	ELFOSABI_SYSV }
58};
59
60int
61main(int argc, char **argv)
62{
63
64	const char *strtype = "FreeBSD";
65	int type = ELFOSABI_FREEBSD;
66	int retval = 0;
67	int ch, change = 0, verbose = 0, force = 0, listed = 0;
68
69	while ((ch = getopt(argc, argv, "f:lt:v")) != -1)
70		switch (ch) {
71		case 'f':
72			if (change)
73				errx(1, "f option incompatible with t option");
74			force = 1;
75			type = atoi(optarg);
76			if (errno == ERANGE || type < 0 || type > 255) {
77				warnx("invalid argument to option f: %s",
78				    optarg);
79				usage();
80			}
81			break;
82		case 'l':
83			printelftypes();
84			listed = 1;
85			break;
86		case 'v':
87			verbose = 1;
88			break;
89		case 't':
90			if (force)
91				errx(1, "t option incompatible with f option");
92			change = 1;
93			strtype = optarg;
94			break;
95		default:
96			usage();
97	}
98	argc -= optind;
99	argv += optind;
100	if (!argc) {
101		if (listed)
102			exit(0);
103		else {
104			warnx("no file(s) specified");
105			usage();
106		}
107	}
108
109	if (!force && (type = elftype(strtype)) == -1) {
110		warnx("invalid ELF type '%s'", strtype);
111		printelftypes();
112		usage();
113	}
114
115	while (argc) {
116		int fd;
117		char buffer[EI_NIDENT];
118
119		if ((fd = open(argv[0], change || force ? O_RDWR : O_RDONLY, 0)) < 0) {
120			warn("error opening file %s", argv[0]);
121			retval = 1;
122			goto fail;
123		}
124		if (read(fd, buffer, EI_NIDENT) < EI_NIDENT) {
125			warnx("file '%s' too short", argv[0]);
126			retval = 1;
127			goto fail;
128		}
129		if (buffer[0] != ELFMAG0 || buffer[1] != ELFMAG1 ||
130		    buffer[2] != ELFMAG2 || buffer[3] != ELFMAG3) {
131			warnx("file '%s' is not ELF format", argv[0]);
132			retval = 1;
133			goto fail;
134		}
135		if (!change && !force) {
136			fprintf(stdout,
137				"File '%s' is of brand '%s' (%u).\n",
138				argv[0], iselftype(buffer[EI_OSABI]),
139				buffer[EI_OSABI]);
140			if (!iselftype(type)) {
141				warnx("ELF ABI Brand '%u' is unknown",
142				      type);
143				printelftypes();
144			}
145		}
146		else {
147			buffer[EI_OSABI] = type;
148			lseek(fd, 0, SEEK_SET);
149			if (write(fd, buffer, EI_NIDENT) != EI_NIDENT) {
150				warn("error writing %s %d", argv[0], fd);
151				retval = 1;
152				goto fail;
153			}
154		}
155fail:
156		close(fd);
157		argc--;
158		argv++;
159	}
160
161	return retval;
162}
163
164static void
165usage(void)
166{
167fprintf(stderr, "usage: brandelf [-f ELF ABI number] [-v] [-l] [-t string] file ...\n");
168	exit(1);
169}
170
171static const char *
172iselftype(int etype)
173{
174	size_t elfwalk;
175
176	for (elfwalk = 0;
177	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
178	     elfwalk++)
179		if (etype == elftypes[elfwalk].value)
180			return elftypes[elfwalk].str;
181	return 0;
182}
183
184static int
185elftype(const char *elfstrtype)
186{
187	size_t elfwalk;
188
189	for (elfwalk = 0;
190	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
191	     elfwalk++)
192		if (strcasecmp(elfstrtype, elftypes[elfwalk].str) == 0)
193			return elftypes[elfwalk].value;
194	return -1;
195}
196
197static void
198printelftypes(void)
199{
200	size_t elfwalk;
201
202	fprintf(stderr, "known ELF types are: ");
203	for (elfwalk = 0;
204	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
205	     elfwalk++)
206		fprintf(stderr, "%s(%u) ", elftypes[elfwalk].str,
207			elftypes[elfwalk].value);
208	fprintf(stderr, "\n");
209}
210