elf2aout.c revision 330449 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2002 Jake Burkholder
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 * 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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: stable/11/usr.bin/elf2aout/elf2aout.c 330449 2018-03-05 07:26:05Z eadler $");
31
32#include <sys/types.h>
33#include <sys/elf64.h>
34#include <sys/endian.h>
35#include <sys/mman.h>
36#include <sys/stat.h>
37
38#include <err.h>
39#include <fcntl.h>
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43#include <unistd.h>
44
45#define	xe16toh(x)	((data == ELFDATA2MSB) ? be16toh(x) : le16toh(x))
46#define	xe32toh(x)	((data == ELFDATA2MSB) ? be32toh(x) : le32toh(x))
47#define	xe64toh(x)	((data == ELFDATA2MSB) ? be64toh(x) : le64toh(x))
48#define	htoxe32(x)	((data == ELFDATA2MSB) ? htobe32(x) : htole32(x))
49
50struct exec {
51	u_int32_t	a_magic;
52	u_int32_t	a_text;
53	u_int32_t	a_data;
54	u_int32_t	a_bss;
55	u_int32_t	a_syms;
56	u_int32_t	a_entry;
57	u_int32_t	a_trsize;
58	u_int32_t	a_drsize;
59};
60#define A_MAGIC 0x01030107
61
62static void usage(void);
63
64/*
65 * elf to a.out converter for freebsd/sparc64 bootblocks.
66 */
67int
68main(int ac, char **av)
69{
70	Elf64_Half phentsize;
71	Elf64_Half machine;
72	Elf64_Half phnum;
73	Elf64_Xword filesz;
74	Elf64_Xword memsz;
75	Elf64_Addr entry;
76	Elf64_Off offset;
77	Elf64_Off phoff;
78	Elf64_Word type;
79	unsigned char data;
80	struct stat sb;
81	struct exec a;
82	Elf64_Phdr *p;
83	Elf64_Ehdr *e;
84	void *v;
85	int efd;
86	int fd;
87	int c;
88	int i;
89
90	fd = STDIN_FILENO;
91	while ((c = getopt(ac, av, "o:")) != -1)
92		switch (c) {
93		case 'o':
94			if ((fd = open(optarg, O_CREAT|O_RDWR, 0644)) < 0)
95				err(1, "%s", optarg);
96			break;
97		case '?':
98		default:
99			usage();
100		}
101	ac -= optind;
102	av += optind;
103	if (ac == 0)
104		usage();
105
106	if ((efd = open(*av, O_RDONLY)) < 0 || fstat(efd, &sb) < 0)
107		err(1, NULL);
108	v = mmap(NULL, sb.st_size, PROT_READ, MAP_SHARED, efd, 0);
109	if ((e = v) == MAP_FAILED)
110		err(1, NULL);
111
112	if (!IS_ELF(*e))
113		errx(1, "not an elf file");
114	if (e->e_ident[EI_CLASS] != ELFCLASS64)
115		errx(1, "wrong class");
116	data = e->e_ident[EI_DATA];
117	if (data != ELFDATA2MSB && data != ELFDATA2LSB)
118		errx(1, "wrong data format");
119	if (e->e_ident[EI_VERSION] != EV_CURRENT)
120		errx(1, "wrong elf version");
121	machine = xe16toh(e->e_machine);
122	if (machine != EM_SPARCV9 && machine != EM_ALPHA)
123		errx(1, "wrong machine type");
124	phentsize = xe16toh(e->e_phentsize);
125	if (phentsize != sizeof(*p))
126		errx(1, "phdr size mismatch");
127
128	entry = xe64toh(e->e_entry);
129	phoff = xe64toh(e->e_phoff);
130	phnum = xe16toh(e->e_phnum);
131	p = (Elf64_Phdr *)((char *)e + phoff);
132	bzero(&a, sizeof(a));
133	for (i = 0; i < phnum; i++) {
134		type = xe32toh(p[i].p_type);
135		switch (type) {
136		case PT_LOAD:
137			if (a.a_magic != 0)
138				errx(1, "too many loadable segments");
139			filesz = xe64toh(p[i].p_filesz);
140			memsz = xe64toh(p[i].p_memsz);
141			offset = xe64toh(p[i].p_offset);
142			a.a_magic = htoxe32(A_MAGIC);
143			a.a_text = htoxe32(filesz);
144			a.a_bss = htoxe32(memsz - filesz);
145			a.a_entry = htoxe32(entry);
146			if (write(fd, &a, sizeof(a)) != sizeof(a) ||
147			    write(fd, (char *)e + offset, filesz) != (ssize_t)filesz)
148				err(1, NULL);
149			break;
150		default:
151			break;
152		}
153	}
154
155	return (0);
156}
157
158static void
159usage(void)
160{
161
162	fprintf(stderr, "usage: elf2aout [-o outfile] infile\n");
163	exit(1);
164}
165