brandelf.c revision 280917 
1/*-
2 * Copyright (c) 2008 Hyogeol Lee
3 * Copyright (c) 2000, 2001 David O'Brien
4 * Copyright (c) 1996 S�ren Schmidt
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer
12 *    in this position and unchanged.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include <sys/types.h>
32#include <sys/stat.h>
33#include <err.h>
34#include <errno.h>
35#include <fcntl.h>
36#include <gelf.h>
37#include <getopt.h>
38#include <libelf.h>
39#include <libelftc.h>
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43#include <unistd.h>
44
45#include "_elftc.h"
46
47ELFTC_VCSID("$Id: brandelf.c 3174 2015-03-27 17:13:41Z emaste $");
48
49static int elftype(const char *);
50static const char *iselftype(int);
51static void printelftypes(void);
52static void printversion(void);
53static void usage(void);
54
55struct ELFtypes {
56	const char *str;
57	int value;
58};
59/* XXX - any more types? */
60static struct ELFtypes elftypes[] = {
61	{ "86Open",	ELFOSABI_86OPEN },
62	{ "AIX",	ELFOSABI_AIX },
63	{ "ARM",	ELFOSABI_ARM },
64	{ "AROS",	ELFOSABI_AROS },
65	{ "FreeBSD",	ELFOSABI_FREEBSD },
66	{ "GNU",	ELFOSABI_GNU },
67	{ "HP/UX",	ELFOSABI_HPUX},
68	{ "Hurd",	ELFOSABI_HURD },
69	{ "IRIX",	ELFOSABI_IRIX },
70	{ "Linux",	ELFOSABI_GNU },
71	{ "Modesto",	ELFOSABI_MODESTO },
72	{ "NSK",	ELFOSABI_NSK },
73	{ "NetBSD",	ELFOSABI_NETBSD},
74	{ "None",	ELFOSABI_NONE},
75	{ "OpenBSD",	ELFOSABI_OPENBSD },
76	{ "OpenVMS",	ELFOSABI_OPENVMS },
77	{ "Standalone",	ELFOSABI_STANDALONE },
78	{ "SVR4",	ELFOSABI_NONE },
79	{ "Solaris",	ELFOSABI_SOLARIS },
80	{ "Tru64",	ELFOSABI_TRU64 }
81};
82
83static struct option brandelf_longopts[] = {
84	{ "help",	no_argument,	NULL,   'h' },
85	{ "version",	no_argument,	NULL, 	'V' },
86	{ NULL,		0,		NULL,	0   }
87};
88
89int
90main(int argc, char **argv)
91{
92	GElf_Ehdr ehdr;
93	Elf *elf;
94	Elf_Kind kind;
95	int type = ELFOSABI_NONE;
96	int retval = 0;
97	int ch, change = 0, force = 0, listed = 0;
98
99	if (elf_version(EV_CURRENT) == EV_NONE)
100		errx(EXIT_FAILURE, "elf_version error");
101
102	while ((ch = getopt_long(argc, argv, "Vf:hlt:v", brandelf_longopts,
103		NULL)) != -1)
104		switch (ch) {
105		case 'f':
106			if (change)
107				errx(EXIT_FAILURE, "ERROR: the -f option is "
108				    "incompatible with the -t option.");
109			force = 1;
110			type = atoi(optarg);
111			if (errno == ERANGE || type < 0 || type > 255) {
112				warnx("ERROR: invalid argument to option "
113				    "-f: %s", optarg);
114				usage();
115			}
116			break;
117		case 'h':
118			usage();
119			break;
120		case 'l':
121			printelftypes();
122			listed = 1;
123			break;
124		case 'v':
125			/* This flag is ignored. */
126			break;
127		case 't':
128			if (force)
129				errx(EXIT_FAILURE, "the -t option is "
130				    "incompatible with the -f option.");
131			if ((type = elftype(optarg)) == -1) {
132				warnx("ERROR: invalid ELF type '%s'", optarg);
133				usage();
134			}
135
136			change = 1;
137			break;
138		case 'V':
139			printversion();
140			break;
141		default:
142			usage();
143	}
144	argc -= optind;
145	argv += optind;
146	if (!argc) {
147		if (listed)
148			exit(0);
149		else {
150			warnx("no file(s) specified");
151			usage();
152		}
153	}
154
155	while (argc) {
156		int fd;
157
158		elf = NULL;
159
160		if ((fd = open(argv[0], (change || force) ? O_RDWR :
161		    O_RDONLY, 0)) < 0) {
162			warn("error opening file %s", argv[0]);
163			retval = 1;
164			goto fail;
165		}
166
167		if ((elf = elf_begin(fd, (change || force) ? ELF_C_RDWR :
168		    ELF_C_READ, NULL)) == NULL) {
169			warnx("elf_begin failed: %s", elf_errmsg(-1));
170			retval = 1;
171			goto fail;
172		}
173
174		if ((kind = elf_kind(elf)) != ELF_K_ELF) {
175			if (kind == ELF_K_AR)
176				warnx("file '%s' is an archive.", argv[0]);
177			else
178				warnx("file '%s' is not an ELF file.",
179				    argv[0]);
180			retval = 1;
181			goto fail;
182		}
183
184		if (gelf_getehdr(elf, &ehdr) == NULL) {
185			warnx("gelf_getehdr: %s", elf_errmsg(-1));
186			retval = 1;
187			goto fail;
188		}
189
190		if (!change && !force) {
191			fprintf(stdout,
192			    "File '%s' is of brand '%s' (%u).\n",
193			    argv[0], iselftype(ehdr.e_ident[EI_OSABI]),
194			    ehdr.e_ident[EI_OSABI]);
195			if (!iselftype(type)) {
196				warnx("ELF ABI Brand '%u' is unknown",
197				      type);
198				printelftypes();
199			}
200		} else {
201
202			/*
203			 * Keep the existing layout of the ELF object.
204			 */
205			if (elf_flagelf(elf, ELF_C_SET, ELF_F_LAYOUT) == 0) {
206				warnx("elf_flagelf failed: %s",
207				    elf_errmsg(-1));
208				retval = 1;
209				goto fail;
210			}
211
212			/*
213			 * Update the ABI type.
214			 */
215			ehdr.e_ident[EI_OSABI] = type;
216			if (gelf_update_ehdr(elf, &ehdr) == 0) {
217				warnx("gelf_update_ehdr error: %s",
218				    elf_errmsg(-1));
219				retval = 1;
220				goto fail;
221			}
222
223			/*
224			 * Write back changes.
225			 */
226			if (elf_update(elf, ELF_C_WRITE) == -1) {
227				warnx("elf_update error: %s", elf_errmsg(-1));
228				retval = 1;
229				goto fail;
230			}
231		}
232fail:
233
234		if (elf)
235			elf_end(elf);
236
237		if (fd >= 0 && close(fd) == -1) {
238			warnx("%s: close error", argv[0]);
239			retval = 1;
240		}
241
242		argc--;
243		argv++;
244	}
245
246	return (retval);
247}
248
249#define	USAGE_MESSAGE	"\
250Usage: %s [options] file...\n\
251  Set or display the ABI field for an ELF object.\n\n\
252  Supported options are:\n\
253  -f NUM                    Set the ELF ABI to the number 'NUM'.\n\
254  -h | --help               Print a usage message and exit.\n\
255  -l                        List known ELF ABI names.\n\
256  -t ABI                    Set the ELF ABI to the value named by \"ABI\".\n\
257  -V | --version            Print a version identifier and exit.\n"
258
259static void
260usage(void)
261{
262	(void) fprintf(stderr, USAGE_MESSAGE, ELFTC_GETPROGNAME());
263	exit(1);
264}
265
266static void
267printversion(void)
268{
269	(void) printf("%s (%s)\n", ELFTC_GETPROGNAME(), elftc_version());
270	exit(0);
271}
272
273static const char *
274iselftype(int etype)
275{
276	size_t elfwalk;
277
278	for (elfwalk = 0;
279	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
280	     elfwalk++)
281		if (etype == elftypes[elfwalk].value)
282			return (elftypes[elfwalk].str);
283	return (0);
284}
285
286static int
287elftype(const char *elfstrtype)
288{
289	size_t elfwalk;
290
291	for (elfwalk = 0;
292	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
293	     elfwalk++)
294		if (strcasecmp(elfstrtype, elftypes[elfwalk].str) == 0)
295			return (elftypes[elfwalk].value);
296	return (-1);
297}
298
299static void
300printelftypes(void)
301{
302	size_t elfwalk;
303
304	(void) printf("Known ELF types are: ");
305	for (elfwalk = 0;
306	     elfwalk < sizeof(elftypes)/sizeof(elftypes[0]);
307	     elfwalk++)
308		(void) printf("%s(%u) ", elftypes[elfwalk].str,
309		    elftypes[elfwalk].value);
310	(void) printf("\n");
311}
312